2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /mpc5xx Files specific to Freescale MPC5xx CPUs
186 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
187 /mpc8xx Files specific to Freescale MPC8xx CPUs
188 /mpc8260 Files specific to Freescale MPC8260 CPUs
189 /mpc85xx Files specific to Freescale MPC85xx CPUs
190 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
191 /lib Architecture specific library files
192 /sh Files generic to SH architecture
193 /cpu CPU specific files
194 /sh2 Files specific to sh2 CPUs
195 /sh3 Files specific to sh3 CPUs
196 /sh4 Files specific to sh4 CPUs
197 /lib Architecture specific library files
198 /sparc Files generic to SPARC architecture
199 /cpu CPU specific files
200 /leon2 Files specific to Gaisler LEON2 SPARC CPU
201 /leon3 Files specific to Gaisler LEON3 SPARC CPU
202 /lib Architecture specific library files
203 /x86 Files generic to x86 architecture
204 /cpu CPU specific files
205 /lib Architecture specific library files
206 /api Machine/arch independent API for external apps
207 /board Board dependent files
208 /common Misc architecture independent functions
209 /disk Code for disk drive partition handling
210 /doc Documentation (don't expect too much)
211 /drivers Commonly used device drivers
212 /dts Contains Makefile for building internal U-Boot fdt.
213 /examples Example code for standalone applications, etc.
214 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
215 /include Header Files
216 /lib Files generic to all architectures
217 /libfdt Library files to support flattened device trees
218 /lzma Library files to support LZMA decompression
219 /lzo Library files to support LZO decompression
221 /post Power On Self Test
222 /spl Secondary Program Loader framework
223 /tools Tools to build S-Record or U-Boot images, etc.
225 Software Configuration:
226 =======================
228 Configuration is usually done using C preprocessor defines; the
229 rationale behind that is to avoid dead code whenever possible.
231 There are two classes of configuration variables:
233 * Configuration _OPTIONS_:
234 These are selectable by the user and have names beginning with
237 * Configuration _SETTINGS_:
238 These depend on the hardware etc. and should not be meddled with if
239 you don't know what you're doing; they have names beginning with
242 Later we will add a configuration tool - probably similar to or even
243 identical to what's used for the Linux kernel. Right now, we have to
244 do the configuration by hand, which means creating some symbolic
245 links and editing some configuration files. We use the TQM8xxL boards
249 Selection of Processor Architecture and Board Type:
250 ---------------------------------------------------
252 For all supported boards there are ready-to-use default
253 configurations available; just type "make <board_name>_defconfig".
255 Example: For a TQM823L module type:
258 make TQM823L_defconfig
260 For the Cogent platform, you need to specify the CPU type as well;
261 e.g. "make cogent_mpc8xx_defconfig". And also configure the cogent
262 directory according to the instructions in cogent/README.
268 U-Boot can be built natively to run on a Linux host using the 'sandbox'
269 board. This allows feature development which is not board- or architecture-
270 specific to be undertaken on a native platform. The sandbox is also used to
271 run some of U-Boot's tests.
273 See board/sandbox/README.sandbox for more details.
276 Board Initialisation Flow:
277 --------------------------
279 This is the intended start-up flow for boards. This should apply for both
280 SPL and U-Boot proper (i.e. they both follow the same rules). At present SPL
281 mostly uses a separate code path, but the funtion names and roles of each
282 function are the same. Some boards or architectures may not conform to this.
283 At least most ARM boards which use CONFIG_SPL_FRAMEWORK conform to this.
285 Execution starts with start.S with three functions called during init after
286 that. The purpose and limitations of each is described below.
289 - purpose: essential init to permit execution to reach board_init_f()
290 - no global_data or BSS
291 - there is no stack (ARMv7 may have one but it will soon be removed)
292 - must not set up SDRAM or use console
293 - must only do the bare minimum to allow execution to continue to
295 - this is almost never needed
296 - return normally from this function
299 - purpose: set up the machine ready for running board_init_r():
300 i.e. SDRAM and serial UART
301 - global_data is available
303 - BSS is not available, so you cannot use global/static variables,
304 only stack variables and global_data
306 Non-SPL-specific notes:
307 - dram_init() is called to set up DRAM. If already done in SPL this
311 - you can override the entire board_init_f() function with your own
313 - preloader_console_init() can be called here in extremis
314 - should set up SDRAM, and anything needed to make the UART work
315 - these is no need to clear BSS, it will be done by crt0.S
316 - must return normally from this function (don't call board_init_r()
319 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
320 this point the stack and global_data are relocated to below
321 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
325 - purpose: main execution, common code
326 - global_data is available
328 - BSS is available, all static/global variables can be used
329 - execution eventually continues to main_loop()
331 Non-SPL-specific notes:
332 - U-Boot is relocated to the top of memory and is now running from
336 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
337 CONFIG_SPL_STACK_R_ADDR points into SDRAM
338 - preloader_console_init() can be called here - typically this is
339 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
340 spl_board_init() function containing this call
341 - loads U-Boot or (in falcon mode) Linux
345 Configuration Options:
346 ----------------------
348 Configuration depends on the combination of board and CPU type; all
349 such information is kept in a configuration file
350 "include/configs/<board_name>.h".
352 Example: For a TQM823L module, all configuration settings are in
353 "include/configs/TQM823L.h".
356 Many of the options are named exactly as the corresponding Linux
357 kernel configuration options. The intention is to make it easier to
358 build a config tool - later.
361 The following options need to be configured:
363 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
365 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
367 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
368 Define exactly one, e.g. CONFIG_ATSTK1002
370 - CPU Module Type: (if CONFIG_COGENT is defined)
371 Define exactly one of
373 --- FIXME --- not tested yet:
374 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
375 CONFIG_CMA287_23, CONFIG_CMA287_50
377 - Motherboard Type: (if CONFIG_COGENT is defined)
378 Define exactly one of
379 CONFIG_CMA101, CONFIG_CMA102
381 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
382 Define one or more of
385 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
386 Define one or more of
387 CONFIG_LCD_HEARTBEAT - update a character position on
388 the LCD display every second with
391 - Marvell Family Member
392 CONFIG_SYS_MVFS - define it if you want to enable
393 multiple fs option at one time
394 for marvell soc family
396 - 8xx CPU Options: (if using an MPC8xx CPU)
397 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
398 get_gclk_freq() cannot work
399 e.g. if there is no 32KHz
400 reference PIT/RTC clock
401 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
404 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
405 CONFIG_SYS_8xx_CPUCLK_MIN
406 CONFIG_SYS_8xx_CPUCLK_MAX
407 CONFIG_8xx_CPUCLK_DEFAULT
408 See doc/README.MPC866
410 CONFIG_SYS_MEASURE_CPUCLK
412 Define this to measure the actual CPU clock instead
413 of relying on the correctness of the configured
414 values. Mostly useful for board bringup to make sure
415 the PLL is locked at the intended frequency. Note
416 that this requires a (stable) reference clock (32 kHz
417 RTC clock or CONFIG_SYS_8XX_XIN)
419 CONFIG_SYS_DELAYED_ICACHE
421 Define this option if you want to enable the
422 ICache only when Code runs from RAM.
427 Specifies that the core is a 64-bit PowerPC implementation (implements
428 the "64" category of the Power ISA). This is necessary for ePAPR
429 compliance, among other possible reasons.
431 CONFIG_SYS_FSL_TBCLK_DIV
433 Defines the core time base clock divider ratio compared to the
434 system clock. On most PQ3 devices this is 8, on newer QorIQ
435 devices it can be 16 or 32. The ratio varies from SoC to Soc.
437 CONFIG_SYS_FSL_PCIE_COMPAT
439 Defines the string to utilize when trying to match PCIe device
440 tree nodes for the given platform.
442 CONFIG_SYS_PPC_E500_DEBUG_TLB
444 Enables a temporary TLB entry to be used during boot to work
445 around limitations in e500v1 and e500v2 external debugger
446 support. This reduces the portions of the boot code where
447 breakpoints and single stepping do not work. The value of this
448 symbol should be set to the TLB1 entry to be used for this
451 CONFIG_SYS_FSL_ERRATUM_A004510
453 Enables a workaround for erratum A004510. If set,
454 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
455 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
457 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
458 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
460 Defines one or two SoC revisions (low 8 bits of SVR)
461 for which the A004510 workaround should be applied.
463 The rest of SVR is either not relevant to the decision
464 of whether the erratum is present (e.g. p2040 versus
465 p2041) or is implied by the build target, which controls
466 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
468 See Freescale App Note 4493 for more information about
471 CONFIG_A003399_NOR_WORKAROUND
472 Enables a workaround for IFC erratum A003399. It is only
473 required during NOR boot.
475 CONFIG_A008044_WORKAROUND
476 Enables a workaround for T1040/T1042 erratum A008044. It is only
477 required during NAND boot and valid for Rev 1.0 SoC revision
479 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
481 This is the value to write into CCSR offset 0x18600
482 according to the A004510 workaround.
484 CONFIG_SYS_FSL_DSP_DDR_ADDR
485 This value denotes start offset of DDR memory which is
486 connected exclusively to the DSP cores.
488 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
489 This value denotes start offset of M2 memory
490 which is directly connected to the DSP core.
492 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
493 This value denotes start offset of M3 memory which is directly
494 connected to the DSP core.
496 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
497 This value denotes start offset of DSP CCSR space.
499 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
500 Single Source Clock is clocking mode present in some of FSL SoC's.
501 In this mode, a single differential clock is used to supply
502 clocks to the sysclock, ddrclock and usbclock.
504 CONFIG_SYS_CPC_REINIT_F
505 This CONFIG is defined when the CPC is configured as SRAM at the
506 time of U-boot entry and is required to be re-initialized.
509 Indicates this SoC supports deep sleep feature. If deep sleep is
510 supported, core will start to execute uboot when wakes up.
512 - Generic CPU options:
513 CONFIG_SYS_GENERIC_GLOBAL_DATA
514 Defines global data is initialized in generic board board_init_f().
515 If this macro is defined, global data is created and cleared in
516 generic board board_init_f(). Without this macro, architecture/board
517 should initialize global data before calling board_init_f().
519 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
521 Defines the endianess of the CPU. Implementation of those
522 values is arch specific.
525 Freescale DDR driver in use. This type of DDR controller is
526 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
529 CONFIG_SYS_FSL_DDR_ADDR
530 Freescale DDR memory-mapped register base.
532 CONFIG_SYS_FSL_DDR_EMU
533 Specify emulator support for DDR. Some DDR features such as
534 deskew training are not available.
536 CONFIG_SYS_FSL_DDRC_GEN1
537 Freescale DDR1 controller.
539 CONFIG_SYS_FSL_DDRC_GEN2
540 Freescale DDR2 controller.
542 CONFIG_SYS_FSL_DDRC_GEN3
543 Freescale DDR3 controller.
545 CONFIG_SYS_FSL_DDRC_GEN4
546 Freescale DDR4 controller.
548 CONFIG_SYS_FSL_DDRC_ARM_GEN3
549 Freescale DDR3 controller for ARM-based SoCs.
552 Board config to use DDR1. It can be enabled for SoCs with
553 Freescale DDR1 or DDR2 controllers, depending on the board
557 Board config to use DDR2. It can be eanbeld for SoCs with
558 Freescale DDR2 or DDR3 controllers, depending on the board
562 Board config to use DDR3. It can be enabled for SoCs with
563 Freescale DDR3 or DDR3L controllers.
566 Board config to use DDR3L. It can be enabled for SoCs with
570 Board config to use DDR4. It can be enabled for SoCs with
573 CONFIG_SYS_FSL_IFC_BE
574 Defines the IFC controller register space as Big Endian
576 CONFIG_SYS_FSL_IFC_LE
577 Defines the IFC controller register space as Little Endian
579 CONFIG_SYS_FSL_PBL_PBI
580 It enables addition of RCW (Power on reset configuration) in built image.
581 Please refer doc/README.pblimage for more details
583 CONFIG_SYS_FSL_PBL_RCW
584 It adds PBI(pre-boot instructions) commands in u-boot build image.
585 PBI commands can be used to configure SoC before it starts the execution.
586 Please refer doc/README.pblimage for more details
589 It adds a target to create boot binary having SPL binary in PBI format
590 concatenated with u-boot binary.
592 CONFIG_SYS_FSL_DDR_BE
593 Defines the DDR controller register space as Big Endian
595 CONFIG_SYS_FSL_DDR_LE
596 Defines the DDR controller register space as Little Endian
598 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
599 Physical address from the view of DDR controllers. It is the
600 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
601 it could be different for ARM SoCs.
603 CONFIG_SYS_FSL_DDR_INTLV_256B
604 DDR controller interleaving on 256-byte. This is a special
605 interleaving mode, handled by Dickens for Freescale layerscape
608 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
609 Number of controllers used as main memory.
611 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
612 Number of controllers used for other than main memory.
614 CONFIG_SYS_FSL_SEC_BE
615 Defines the SEC controller register space as Big Endian
617 CONFIG_SYS_FSL_SEC_LE
618 Defines the SEC controller register space as Little Endian
620 - Intel Monahans options:
621 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
623 Defines the Monahans run mode to oscillator
624 ratio. Valid values are 8, 16, 24, 31. The core
625 frequency is this value multiplied by 13 MHz.
627 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
629 Defines the Monahans turbo mode to oscillator
630 ratio. Valid values are 1 (default if undefined) and
631 2. The core frequency as calculated above is multiplied
635 CONFIG_SYS_INIT_SP_OFFSET
637 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
638 pointer. This is needed for the temporary stack before
641 CONFIG_SYS_MIPS_CACHE_MODE
643 Cache operation mode for the MIPS CPU.
644 See also arch/mips/include/asm/mipsregs.h.
646 CONF_CM_CACHABLE_NO_WA
649 CONF_CM_CACHABLE_NONCOHERENT
653 CONF_CM_CACHABLE_ACCELERATED
655 CONFIG_SYS_XWAY_EBU_BOOTCFG
657 Special option for Lantiq XWAY SoCs for booting from NOR flash.
658 See also arch/mips/cpu/mips32/start.S.
660 CONFIG_XWAY_SWAP_BYTES
662 Enable compilation of tools/xway-swap-bytes needed for Lantiq
663 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
664 be swapped if a flash programmer is used.
667 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
669 Select high exception vectors of the ARM core, e.g., do not
670 clear the V bit of the c1 register of CP15.
672 CONFIG_SYS_THUMB_BUILD
674 Use this flag to build U-Boot using the Thumb instruction
675 set for ARM architectures. Thumb instruction set provides
676 better code density. For ARM architectures that support
677 Thumb2 this flag will result in Thumb2 code generated by
680 CONFIG_ARM_ERRATA_716044
681 CONFIG_ARM_ERRATA_742230
682 CONFIG_ARM_ERRATA_743622
683 CONFIG_ARM_ERRATA_751472
684 CONFIG_ARM_ERRATA_794072
685 CONFIG_ARM_ERRATA_761320
687 If set, the workarounds for these ARM errata are applied early
688 during U-Boot startup. Note that these options force the
689 workarounds to be applied; no CPU-type/version detection
690 exists, unlike the similar options in the Linux kernel. Do not
691 set these options unless they apply!
693 NOTE: The following can be machine specific errata. These
694 do have ability to provide rudimentary version and machine
695 specific checks, but expect no product checks.
696 CONFIG_ARM_ERRATA_454179
697 CONFIG_ARM_ERRATA_798870
700 CONFIG_TEGRA_SUPPORT_NON_SECURE
702 Support executing U-Boot in non-secure (NS) mode. Certain
703 impossible actions will be skipped if the CPU is in NS mode,
704 such as ARM architectural timer initialization.
707 Driver model is a new framework for devices in U-Boot
708 introduced in early 2014. U-Boot is being progressively
709 moved over to this. It offers a consistent device structure,
710 supports grouping devices into classes and has built-in
711 handling of platform data and device tree.
713 To enable transition to driver model in a relatively
714 painful fashion, each subsystem can be independently
715 switched between the legacy/ad-hoc approach and the new
716 driver model using the options below. Also, many uclass
717 interfaces include compatibility features which may be
718 removed once the conversion of that subsystem is complete.
719 As a result, the API provided by the subsystem may in fact
720 not change with driver model.
722 See doc/driver-model/README.txt for more information.
726 Enable driver model. This brings in the core support,
727 including scanning of platform data on start-up. If
728 CONFIG_OF_CONTROL is enabled, the device tree will be
729 scanned also when available.
733 Enable driver model test commands. These allow you to print
734 out the driver model tree and the uclasses.
738 Enable some demo devices and the 'demo' command. These are
739 really only useful for playing around while trying to
740 understand driver model in sandbox.
744 Enable driver model in SPL. You will need to provide a
745 suitable malloc() implementation. If you are not using the
746 full malloc() enabled by CONFIG_SYS_SPL_MALLOC_START,
747 consider using CONFIG_SYS_MALLOC_SIMPLE. In that case you
748 must provide CONFIG_SYS_MALLOC_F_LEN to set the size.
749 In most cases driver model will only allocate a few uclasses
750 and devices in SPL, so 1KB should be enable. See
751 CONFIG_SYS_MALLOC_F_LEN for more details on how to enable
756 Enable driver model for serial. This replaces
757 drivers/serial/serial.c with the serial uclass, which
758 implements serial_putc() etc. The uclass interface is
759 defined in include/serial.h.
763 Enable driver model for GPIO access. The standard GPIO
764 interface (gpio_get_value(), etc.) is then implemented by
765 the GPIO uclass. Drivers provide methods to query the
766 particular GPIOs that they provide. The uclass interface
767 is defined in include/asm-generic/gpio.h.
771 Enable driver model for SPI. The SPI slave interface
772 (spi_setup_slave(), spi_xfer(), etc.) is then implemented by
773 the SPI uclass. Drivers provide methods to access the SPI
774 buses that they control. The uclass interface is defined in
775 include/spi.h. The existing spi_slave structure is attached
776 as 'parent data' to every slave on each bus. Slaves
777 typically use driver-private data instead of extending the
782 Enable driver model for SPI flash. This SPI flash interface
783 (spi_flash_probe(), spi_flash_write(), etc.) is then
784 implemented by the SPI flash uclass. There is one standard
785 SPI flash driver which knows how to probe most chips
786 supported by U-Boot. The uclass interface is defined in
787 include/spi_flash.h, but is currently fully compatible
788 with the old interface to avoid confusion and duplication
789 during the transition parent. SPI and SPI flash must be
790 enabled together (it is not possible to use driver model
791 for one and not the other).
795 Enable driver model for the Chrome OS EC interface. This
796 allows the cros_ec SPI driver to operate with CONFIG_DM_SPI
797 but otherwise makes few changes. Since cros_ec also supports
798 I2C and LPC (which don't support driver model yet), a full
799 conversion is not yet possible.
802 ** Code size options: The following options are enabled by
803 default except in SPL. Enable them explicitly to get these
808 Enable the dm_warn() function. This can use up quite a bit
809 of space for its strings.
813 Enable registering a serial device with the stdio library.
815 CONFIG_DM_DEVICE_REMOVE
817 Enable removing of devices.
819 - Linux Kernel Interface:
822 U-Boot stores all clock information in Hz
823 internally. For binary compatibility with older Linux
824 kernels (which expect the clocks passed in the
825 bd_info data to be in MHz) the environment variable
826 "clocks_in_mhz" can be defined so that U-Boot
827 converts clock data to MHZ before passing it to the
829 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
830 "clocks_in_mhz=1" is automatically included in the
833 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
835 When transferring memsize parameter to Linux, some versions
836 expect it to be in bytes, others in MB.
837 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
841 New kernel versions are expecting firmware settings to be
842 passed using flattened device trees (based on open firmware
846 * New libfdt-based support
847 * Adds the "fdt" command
848 * The bootm command automatically updates the fdt
850 OF_CPU - The proper name of the cpus node (only required for
851 MPC512X and MPC5xxx based boards).
852 OF_SOC - The proper name of the soc node (only required for
853 MPC512X and MPC5xxx based boards).
854 OF_TBCLK - The timebase frequency.
855 OF_STDOUT_PATH - The path to the console device
857 boards with QUICC Engines require OF_QE to set UCC MAC
860 CONFIG_OF_BOARD_SETUP
862 Board code has addition modification that it wants to make
863 to the flat device tree before handing it off to the kernel
865 CONFIG_OF_SYSTEM_SETUP
867 Other code has addition modification that it wants to make
868 to the flat device tree before handing it off to the kernel.
869 This causes ft_system_setup() to be called before booting
874 This define fills in the correct boot CPU in the boot
875 param header, the default value is zero if undefined.
879 U-Boot can detect if an IDE device is present or not.
880 If not, and this new config option is activated, U-Boot
881 removes the ATA node from the DTS before booting Linux,
882 so the Linux IDE driver does not probe the device and
883 crash. This is needed for buggy hardware (uc101) where
884 no pull down resistor is connected to the signal IDE5V_DD7.
886 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
888 This setting is mandatory for all boards that have only one
889 machine type and must be used to specify the machine type
890 number as it appears in the ARM machine registry
891 (see http://www.arm.linux.org.uk/developer/machines/).
892 Only boards that have multiple machine types supported
893 in a single configuration file and the machine type is
894 runtime discoverable, do not have to use this setting.
896 - vxWorks boot parameters:
898 bootvx constructs a valid bootline using the following
899 environments variables: bootfile, ipaddr, serverip, hostname.
900 It loads the vxWorks image pointed bootfile.
902 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
903 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
904 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
905 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
907 CONFIG_SYS_VXWORKS_ADD_PARAMS
909 Add it at the end of the bootline. E.g "u=username pw=secret"
911 Note: If a "bootargs" environment is defined, it will overwride
912 the defaults discussed just above.
914 - Cache Configuration:
915 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
916 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
917 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
919 - Cache Configuration for ARM:
920 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
922 CONFIG_SYS_PL310_BASE - Physical base address of PL310
923 controller register space
928 Define this if you want support for Amba PrimeCell PL010 UARTs.
932 Define this if you want support for Amba PrimeCell PL011 UARTs.
936 If you have Amba PrimeCell PL011 UARTs, set this variable to
937 the clock speed of the UARTs.
941 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
942 define this to a list of base addresses for each (supported)
943 port. See e.g. include/configs/versatile.h
945 CONFIG_PL011_SERIAL_RLCR
947 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
948 have separate receive and transmit line control registers. Set
949 this variable to initialize the extra register.
951 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
953 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
954 boot loader that has already initialized the UART. Define this
955 variable to flush the UART at init time.
957 CONFIG_SERIAL_HW_FLOW_CONTROL
959 Define this variable to enable hw flow control in serial driver.
960 Current user of this option is drivers/serial/nsl16550.c driver
963 Depending on board, define exactly one serial port
964 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
965 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
966 console by defining CONFIG_8xx_CONS_NONE
968 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
969 port routines must be defined elsewhere
970 (i.e. serial_init(), serial_getc(), ...)
973 Enables console device for a color framebuffer. Needs following
974 defines (cf. smiLynxEM, i8042)
975 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
977 VIDEO_HW_RECTFILL graphic chip supports
980 VIDEO_HW_BITBLT graphic chip supports
981 bit-blit (cf. smiLynxEM)
982 VIDEO_VISIBLE_COLS visible pixel columns
984 VIDEO_VISIBLE_ROWS visible pixel rows
985 VIDEO_PIXEL_SIZE bytes per pixel
986 VIDEO_DATA_FORMAT graphic data format
987 (0-5, cf. cfb_console.c)
988 VIDEO_FB_ADRS framebuffer address
989 VIDEO_KBD_INIT_FCT keyboard int fct
990 (i.e. i8042_kbd_init())
991 VIDEO_TSTC_FCT test char fct
993 VIDEO_GETC_FCT get char fct
995 CONFIG_CONSOLE_CURSOR cursor drawing on/off
996 (requires blink timer
998 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
999 CONFIG_CONSOLE_TIME display time/date info in
1001 (requires CONFIG_CMD_DATE)
1002 CONFIG_VIDEO_LOGO display Linux logo in
1004 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
1005 linux_logo.h for logo.
1006 Requires CONFIG_VIDEO_LOGO
1007 CONFIG_CONSOLE_EXTRA_INFO
1008 additional board info beside
1011 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
1012 a limited number of ANSI escape sequences (cursor control,
1013 erase functions and limited graphics rendition control).
1015 When CONFIG_CFB_CONSOLE is defined, video console is
1016 default i/o. Serial console can be forced with
1017 environment 'console=serial'.
1019 When CONFIG_SILENT_CONSOLE is defined, all console
1020 messages (by U-Boot and Linux!) can be silenced with
1021 the "silent" environment variable. See
1022 doc/README.silent for more information.
1024 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
1026 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
1030 CONFIG_BAUDRATE - in bps
1031 Select one of the baudrates listed in
1032 CONFIG_SYS_BAUDRATE_TABLE, see below.
1033 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
1035 - Console Rx buffer length
1036 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
1037 the maximum receive buffer length for the SMC.
1038 This option is actual only for 82xx and 8xx possible.
1039 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
1040 must be defined, to setup the maximum idle timeout for
1043 - Pre-Console Buffer:
1044 Prior to the console being initialised (i.e. serial UART
1045 initialised etc) all console output is silently discarded.
1046 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
1047 buffer any console messages prior to the console being
1048 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
1049 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
1050 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
1051 bytes are output before the console is initialised, the
1052 earlier bytes are discarded.
1054 'Sane' compilers will generate smaller code if
1055 CONFIG_PRE_CON_BUF_SZ is a power of 2
1057 - Safe printf() functions
1058 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
1059 the printf() functions. These are defined in
1060 include/vsprintf.h and include snprintf(), vsnprintf() and
1061 so on. Code size increase is approximately 300-500 bytes.
1062 If this option is not given then these functions will
1063 silently discard their buffer size argument - this means
1064 you are not getting any overflow checking in this case.
1066 - Boot Delay: CONFIG_BOOTDELAY - in seconds
1067 Delay before automatically booting the default image;
1068 set to -1 to disable autoboot.
1069 set to -2 to autoboot with no delay and not check for abort
1070 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
1072 See doc/README.autoboot for these options that
1073 work with CONFIG_BOOTDELAY. None are required.
1074 CONFIG_BOOT_RETRY_TIME
1075 CONFIG_BOOT_RETRY_MIN
1076 CONFIG_AUTOBOOT_KEYED
1077 CONFIG_AUTOBOOT_PROMPT
1078 CONFIG_AUTOBOOT_DELAY_STR
1079 CONFIG_AUTOBOOT_STOP_STR
1080 CONFIG_AUTOBOOT_DELAY_STR2
1081 CONFIG_AUTOBOOT_STOP_STR2
1082 CONFIG_ZERO_BOOTDELAY_CHECK
1083 CONFIG_RESET_TO_RETRY
1087 Only needed when CONFIG_BOOTDELAY is enabled;
1088 define a command string that is automatically executed
1089 when no character is read on the console interface
1090 within "Boot Delay" after reset.
1093 This can be used to pass arguments to the bootm
1094 command. The value of CONFIG_BOOTARGS goes into the
1095 environment value "bootargs".
1097 CONFIG_RAMBOOT and CONFIG_NFSBOOT
1098 The value of these goes into the environment as
1099 "ramboot" and "nfsboot" respectively, and can be used
1100 as a convenience, when switching between booting from
1104 CONFIG_BOOTCOUNT_LIMIT
1105 Implements a mechanism for detecting a repeating reboot
1107 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
1109 CONFIG_BOOTCOUNT_ENV
1110 If no softreset save registers are found on the hardware
1111 "bootcount" is stored in the environment. To prevent a
1112 saveenv on all reboots, the environment variable
1113 "upgrade_available" is used. If "upgrade_available" is
1114 0, "bootcount" is always 0, if "upgrade_available" is
1115 1 "bootcount" is incremented in the environment.
1116 So the Userspace Applikation must set the "upgrade_available"
1117 and "bootcount" variable to 0, if a boot was successfully.
1119 - Pre-Boot Commands:
1122 When this option is #defined, the existence of the
1123 environment variable "preboot" will be checked
1124 immediately before starting the CONFIG_BOOTDELAY
1125 countdown and/or running the auto-boot command resp.
1126 entering interactive mode.
1128 This feature is especially useful when "preboot" is
1129 automatically generated or modified. For an example
1130 see the LWMON board specific code: here "preboot" is
1131 modified when the user holds down a certain
1132 combination of keys on the (special) keyboard when
1135 - Serial Download Echo Mode:
1137 If defined to 1, all characters received during a
1138 serial download (using the "loads" command) are
1139 echoed back. This might be needed by some terminal
1140 emulations (like "cu"), but may as well just take
1141 time on others. This setting #define's the initial
1142 value of the "loads_echo" environment variable.
1144 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
1145 CONFIG_KGDB_BAUDRATE
1146 Select one of the baudrates listed in
1147 CONFIG_SYS_BAUDRATE_TABLE, see below.
1149 - Monitor Functions:
1150 Monitor commands can be included or excluded
1151 from the build by using the #include files
1152 <config_cmd_all.h> and #undef'ing unwanted
1153 commands, or using <config_cmd_default.h>
1154 and augmenting with additional #define's
1155 for wanted commands.
1157 The default command configuration includes all commands
1158 except those marked below with a "*".
1160 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
1161 CONFIG_CMD_ASKENV * ask for env variable
1162 CONFIG_CMD_BDI bdinfo
1163 CONFIG_CMD_BEDBUG * Include BedBug Debugger
1164 CONFIG_CMD_BMP * BMP support
1165 CONFIG_CMD_BSP * Board specific commands
1166 CONFIG_CMD_BOOTD bootd
1167 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
1168 CONFIG_CMD_CACHE * icache, dcache
1169 CONFIG_CMD_CLK * clock command support
1170 CONFIG_CMD_CONSOLE coninfo
1171 CONFIG_CMD_CRC32 * crc32
1172 CONFIG_CMD_DATE * support for RTC, date/time...
1173 CONFIG_CMD_DHCP * DHCP support
1174 CONFIG_CMD_DIAG * Diagnostics
1175 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
1176 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
1177 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
1178 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
1179 CONFIG_CMD_DTT * Digital Therm and Thermostat
1180 CONFIG_CMD_ECHO echo arguments
1181 CONFIG_CMD_EDITENV edit env variable
1182 CONFIG_CMD_EEPROM * EEPROM read/write support
1183 CONFIG_CMD_ELF * bootelf, bootvx
1184 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
1185 CONFIG_CMD_ENV_FLAGS * display details about env flags
1186 CONFIG_CMD_ENV_EXISTS * check existence of env variable
1187 CONFIG_CMD_EXPORTENV * export the environment
1188 CONFIG_CMD_EXT2 * ext2 command support
1189 CONFIG_CMD_EXT4 * ext4 command support
1190 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
1191 that work for multiple fs types
1192 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
1193 CONFIG_CMD_SAVEENV saveenv
1194 CONFIG_CMD_FDC * Floppy Disk Support
1195 CONFIG_CMD_FAT * FAT command support
1196 CONFIG_CMD_FLASH flinfo, erase, protect
1197 CONFIG_CMD_FPGA FPGA device initialization support
1198 CONFIG_CMD_FUSE * Device fuse support
1199 CONFIG_CMD_GETTIME * Get time since boot
1200 CONFIG_CMD_GO * the 'go' command (exec code)
1201 CONFIG_CMD_GREPENV * search environment
1202 CONFIG_CMD_HASH * calculate hash / digest
1203 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
1204 CONFIG_CMD_I2C * I2C serial bus support
1205 CONFIG_CMD_IDE * IDE harddisk support
1206 CONFIG_CMD_IMI iminfo
1207 CONFIG_CMD_IMLS List all images found in NOR flash
1208 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1209 CONFIG_CMD_IMMAP * IMMR dump support
1210 CONFIG_CMD_IOTRACE * I/O tracing for debugging
1211 CONFIG_CMD_IMPORTENV * import an environment
1212 CONFIG_CMD_INI * import data from an ini file into the env
1213 CONFIG_CMD_IRQ * irqinfo
1214 CONFIG_CMD_ITEST Integer/string test of 2 values
1215 CONFIG_CMD_JFFS2 * JFFS2 Support
1216 CONFIG_CMD_KGDB * kgdb
1217 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1218 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1220 CONFIG_CMD_LOADB loadb
1221 CONFIG_CMD_LOADS loads
1222 CONFIG_CMD_MD5SUM * print md5 message digest
1223 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1224 CONFIG_CMD_MEMINFO * Display detailed memory information
1225 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1227 CONFIG_CMD_MEMTEST * mtest
1228 CONFIG_CMD_MISC Misc functions like sleep etc
1229 CONFIG_CMD_MMC * MMC memory mapped support
1230 CONFIG_CMD_MII * MII utility commands
1231 CONFIG_CMD_MTDPARTS * MTD partition support
1232 CONFIG_CMD_NAND * NAND support
1233 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1234 CONFIG_CMD_NFS NFS support
1235 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1236 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1237 CONFIG_CMD_PCI * pciinfo
1238 CONFIG_CMD_PCMCIA * PCMCIA support
1239 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1241 CONFIG_CMD_PORTIO * Port I/O
1242 CONFIG_CMD_READ * Read raw data from partition
1243 CONFIG_CMD_REGINFO * Register dump
1244 CONFIG_CMD_RUN run command in env variable
1245 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1246 CONFIG_CMD_SAVES * save S record dump
1247 CONFIG_CMD_SCSI * SCSI Support
1248 CONFIG_CMD_SDRAM * print SDRAM configuration information
1249 (requires CONFIG_CMD_I2C)
1250 CONFIG_CMD_SETGETDCR Support for DCR Register access
1252 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1253 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1254 (requires CONFIG_CMD_MEMORY)
1255 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1256 CONFIG_CMD_SOURCE "source" command Support
1257 CONFIG_CMD_SPI * SPI serial bus support
1258 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1259 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1260 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1261 CONFIG_CMD_TIMER * access to the system tick timer
1262 CONFIG_CMD_USB * USB support
1263 CONFIG_CMD_CDP * Cisco Discover Protocol support
1264 CONFIG_CMD_MFSL * Microblaze FSL support
1265 CONFIG_CMD_XIMG Load part of Multi Image
1266 CONFIG_CMD_UUID * Generate random UUID or GUID string
1268 EXAMPLE: If you want all functions except of network
1269 support you can write:
1271 #include "config_cmd_all.h"
1272 #undef CONFIG_CMD_NET
1275 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1277 Note: Don't enable the "icache" and "dcache" commands
1278 (configuration option CONFIG_CMD_CACHE) unless you know
1279 what you (and your U-Boot users) are doing. Data
1280 cache cannot be enabled on systems like the 8xx or
1281 8260 (where accesses to the IMMR region must be
1282 uncached), and it cannot be disabled on all other
1283 systems where we (mis-) use the data cache to hold an
1284 initial stack and some data.
1287 XXX - this list needs to get updated!
1289 - Regular expression support:
1291 If this variable is defined, U-Boot is linked against
1292 the SLRE (Super Light Regular Expression) library,
1293 which adds regex support to some commands, as for
1294 example "env grep" and "setexpr".
1298 If this variable is defined, U-Boot will use a device tree
1299 to configure its devices, instead of relying on statically
1300 compiled #defines in the board file. This option is
1301 experimental and only available on a few boards. The device
1302 tree is available in the global data as gd->fdt_blob.
1304 U-Boot needs to get its device tree from somewhere. This can
1305 be done using one of the two options below:
1308 If this variable is defined, U-Boot will embed a device tree
1309 binary in its image. This device tree file should be in the
1310 board directory and called <soc>-<board>.dts. The binary file
1311 is then picked up in board_init_f() and made available through
1312 the global data structure as gd->blob.
1315 If this variable is defined, U-Boot will build a device tree
1316 binary. It will be called u-boot.dtb. Architecture-specific
1317 code will locate it at run-time. Generally this works by:
1319 cat u-boot.bin u-boot.dtb >image.bin
1321 and in fact, U-Boot does this for you, creating a file called
1322 u-boot-dtb.bin which is useful in the common case. You can
1323 still use the individual files if you need something more
1328 If this variable is defined, it enables watchdog
1329 support for the SoC. There must be support in the SoC
1330 specific code for a watchdog. For the 8xx and 8260
1331 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1332 register. When supported for a specific SoC is
1333 available, then no further board specific code should
1334 be needed to use it.
1337 When using a watchdog circuitry external to the used
1338 SoC, then define this variable and provide board
1339 specific code for the "hw_watchdog_reset" function.
1341 CONFIG_AT91_HW_WDT_TIMEOUT
1342 specify the timeout in seconds. default 2 seconds.
1345 CONFIG_VERSION_VARIABLE
1346 If this variable is defined, an environment variable
1347 named "ver" is created by U-Boot showing the U-Boot
1348 version as printed by the "version" command.
1349 Any change to this variable will be reverted at the
1354 When CONFIG_CMD_DATE is selected, the type of the RTC
1355 has to be selected, too. Define exactly one of the
1358 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1359 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1360 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1361 CONFIG_RTC_MC146818 - use MC146818 RTC
1362 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1363 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1364 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1365 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1366 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1367 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1368 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1369 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1370 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1373 Note that if the RTC uses I2C, then the I2C interface
1374 must also be configured. See I2C Support, below.
1377 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1379 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1380 chip-ngpio pairs that tell the PCA953X driver the number of
1381 pins supported by a particular chip.
1383 Note that if the GPIO device uses I2C, then the I2C interface
1384 must also be configured. See I2C Support, below.
1387 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1388 accesses and can checksum them or write a list of them out
1389 to memory. See the 'iotrace' command for details. This is
1390 useful for testing device drivers since it can confirm that
1391 the driver behaves the same way before and after a code
1392 change. Currently this is supported on sandbox and arm. To
1393 add support for your architecture, add '#include <iotrace.h>'
1394 to the bottom of arch/<arch>/include/asm/io.h and test.
1396 Example output from the 'iotrace stats' command is below.
1397 Note that if the trace buffer is exhausted, the checksum will
1398 still continue to operate.
1401 Start: 10000000 (buffer start address)
1402 Size: 00010000 (buffer size)
1403 Offset: 00000120 (current buffer offset)
1404 Output: 10000120 (start + offset)
1405 Count: 00000018 (number of trace records)
1406 CRC32: 9526fb66 (CRC32 of all trace records)
1408 - Timestamp Support:
1410 When CONFIG_TIMESTAMP is selected, the timestamp
1411 (date and time) of an image is printed by image
1412 commands like bootm or iminfo. This option is
1413 automatically enabled when you select CONFIG_CMD_DATE .
1415 - Partition Labels (disklabels) Supported:
1416 Zero or more of the following:
1417 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1418 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1419 Intel architecture, USB sticks, etc.
1420 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1421 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1422 bootloader. Note 2TB partition limit; see
1424 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1426 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1427 CONFIG_CMD_SCSI) you must configure support for at
1428 least one non-MTD partition type as well.
1431 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1432 board configurations files but used nowhere!
1434 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1435 be performed by calling the function
1436 ide_set_reset(int reset)
1437 which has to be defined in a board specific file
1442 Set this to enable ATAPI support.
1447 Set this to enable support for disks larger than 137GB
1448 Also look at CONFIG_SYS_64BIT_LBA.
1449 Whithout these , LBA48 support uses 32bit variables and will 'only'
1450 support disks up to 2.1TB.
1452 CONFIG_SYS_64BIT_LBA:
1453 When enabled, makes the IDE subsystem use 64bit sector addresses.
1457 At the moment only there is only support for the
1458 SYM53C8XX SCSI controller; define
1459 CONFIG_SCSI_SYM53C8XX to enable it.
1461 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1462 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1463 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1464 maximum numbers of LUNs, SCSI ID's and target
1466 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1468 The environment variable 'scsidevs' is set to the number of
1469 SCSI devices found during the last scan.
1471 - NETWORK Support (PCI):
1473 Support for Intel 8254x/8257x gigabit chips.
1476 Utility code for direct access to the SPI bus on Intel 8257x.
1477 This does not do anything useful unless you set at least one
1478 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1480 CONFIG_E1000_SPI_GENERIC
1481 Allow generic access to the SPI bus on the Intel 8257x, for
1482 example with the "sspi" command.
1485 Management command for E1000 devices. When used on devices
1486 with SPI support you can reprogram the EEPROM from U-Boot.
1488 CONFIG_E1000_FALLBACK_MAC
1489 default MAC for empty EEPROM after production.
1492 Support for Intel 82557/82559/82559ER chips.
1493 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1494 write routine for first time initialisation.
1497 Support for Digital 2114x chips.
1498 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1499 modem chip initialisation (KS8761/QS6611).
1502 Support for National dp83815 chips.
1505 Support for National dp8382[01] gigabit chips.
1507 - NETWORK Support (other):
1509 CONFIG_DRIVER_AT91EMAC
1510 Support for AT91RM9200 EMAC.
1513 Define this to use reduced MII inteface
1515 CONFIG_DRIVER_AT91EMAC_QUIET
1516 If this defined, the driver is quiet.
1517 The driver doen't show link status messages.
1519 CONFIG_CALXEDA_XGMAC
1520 Support for the Calxeda XGMAC device
1523 Support for SMSC's LAN91C96 chips.
1525 CONFIG_LAN91C96_BASE
1526 Define this to hold the physical address
1527 of the LAN91C96's I/O space
1529 CONFIG_LAN91C96_USE_32_BIT
1530 Define this to enable 32 bit addressing
1533 Support for SMSC's LAN91C111 chip
1535 CONFIG_SMC91111_BASE
1536 Define this to hold the physical address
1537 of the device (I/O space)
1539 CONFIG_SMC_USE_32_BIT
1540 Define this if data bus is 32 bits
1542 CONFIG_SMC_USE_IOFUNCS
1543 Define this to use i/o functions instead of macros
1544 (some hardware wont work with macros)
1546 CONFIG_DRIVER_TI_EMAC
1547 Support for davinci emac
1549 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1550 Define this if you have more then 3 PHYs.
1553 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1555 CONFIG_FTGMAC100_EGIGA
1556 Define this to use GE link update with gigabit PHY.
1557 Define this if FTGMAC100 is connected to gigabit PHY.
1558 If your system has 10/100 PHY only, it might not occur
1559 wrong behavior. Because PHY usually return timeout or
1560 useless data when polling gigabit status and gigabit
1561 control registers. This behavior won't affect the
1562 correctnessof 10/100 link speed update.
1565 Support for SMSC's LAN911x and LAN921x chips
1568 Define this to hold the physical address
1569 of the device (I/O space)
1571 CONFIG_SMC911X_32_BIT
1572 Define this if data bus is 32 bits
1574 CONFIG_SMC911X_16_BIT
1575 Define this if data bus is 16 bits. If your processor
1576 automatically converts one 32 bit word to two 16 bit
1577 words you may also try CONFIG_SMC911X_32_BIT.
1580 Support for Renesas on-chip Ethernet controller
1582 CONFIG_SH_ETHER_USE_PORT
1583 Define the number of ports to be used
1585 CONFIG_SH_ETHER_PHY_ADDR
1586 Define the ETH PHY's address
1588 CONFIG_SH_ETHER_CACHE_WRITEBACK
1589 If this option is set, the driver enables cache flush.
1593 Support for PWM modul on the imx6.
1597 Support TPM devices.
1600 Support for i2c bus TPM devices. Only one device
1601 per system is supported at this time.
1603 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1604 Define the the i2c bus number for the TPM device
1606 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1607 Define the TPM's address on the i2c bus
1609 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1610 Define the burst count bytes upper limit
1612 CONFIG_TPM_ATMEL_TWI
1613 Support for Atmel TWI TPM device. Requires I2C support.
1616 Support for generic parallel port TPM devices. Only one device
1617 per system is supported at this time.
1619 CONFIG_TPM_TIS_BASE_ADDRESS
1620 Base address where the generic TPM device is mapped
1621 to. Contemporary x86 systems usually map it at
1625 Add tpm monitor functions.
1626 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1627 provides monitor access to authorized functions.
1630 Define this to enable the TPM support library which provides
1631 functional interfaces to some TPM commands.
1632 Requires support for a TPM device.
1634 CONFIG_TPM_AUTH_SESSIONS
1635 Define this to enable authorized functions in the TPM library.
1636 Requires CONFIG_TPM and CONFIG_SHA1.
1639 At the moment only the UHCI host controller is
1640 supported (PIP405, MIP405, MPC5200); define
1641 CONFIG_USB_UHCI to enable it.
1642 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1643 and define CONFIG_USB_STORAGE to enable the USB
1646 Supported are USB Keyboards and USB Floppy drives
1648 MPC5200 USB requires additional defines:
1650 for 528 MHz Clock: 0x0001bbbb
1654 for differential drivers: 0x00001000
1655 for single ended drivers: 0x00005000
1656 for differential drivers on PSC3: 0x00000100
1657 for single ended drivers on PSC3: 0x00004100
1658 CONFIG_SYS_USB_EVENT_POLL
1659 May be defined to allow interrupt polling
1660 instead of using asynchronous interrupts
1662 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1663 txfilltuning field in the EHCI controller on reset.
1665 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1666 HW module registers.
1669 Define the below if you wish to use the USB console.
1670 Once firmware is rebuilt from a serial console issue the
1671 command "setenv stdin usbtty; setenv stdout usbtty" and
1672 attach your USB cable. The Unix command "dmesg" should print
1673 it has found a new device. The environment variable usbtty
1674 can be set to gserial or cdc_acm to enable your device to
1675 appear to a USB host as a Linux gserial device or a
1676 Common Device Class Abstract Control Model serial device.
1677 If you select usbtty = gserial you should be able to enumerate
1679 # modprobe usbserial vendor=0xVendorID product=0xProductID
1680 else if using cdc_acm, simply setting the environment
1681 variable usbtty to be cdc_acm should suffice. The following
1682 might be defined in YourBoardName.h
1685 Define this to build a UDC device
1688 Define this to have a tty type of device available to
1689 talk to the UDC device
1692 Define this to enable the high speed support for usb
1693 device and usbtty. If this feature is enabled, a routine
1694 int is_usbd_high_speed(void)
1695 also needs to be defined by the driver to dynamically poll
1696 whether the enumeration has succeded at high speed or full
1699 CONFIG_SYS_CONSOLE_IS_IN_ENV
1700 Define this if you want stdin, stdout &/or stderr to
1704 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1705 Derive USB clock from external clock "blah"
1706 - CONFIG_SYS_USB_EXTC_CLK 0x02
1708 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1709 Derive USB clock from brgclk
1710 - CONFIG_SYS_USB_BRG_CLK 0x04
1712 If you have a USB-IF assigned VendorID then you may wish to
1713 define your own vendor specific values either in BoardName.h
1714 or directly in usbd_vendor_info.h. If you don't define
1715 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1716 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1717 should pretend to be a Linux device to it's target host.
1719 CONFIG_USBD_MANUFACTURER
1720 Define this string as the name of your company for
1721 - CONFIG_USBD_MANUFACTURER "my company"
1723 CONFIG_USBD_PRODUCT_NAME
1724 Define this string as the name of your product
1725 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1727 CONFIG_USBD_VENDORID
1728 Define this as your assigned Vendor ID from the USB
1729 Implementors Forum. This *must* be a genuine Vendor ID
1730 to avoid polluting the USB namespace.
1731 - CONFIG_USBD_VENDORID 0xFFFF
1733 CONFIG_USBD_PRODUCTID
1734 Define this as the unique Product ID
1736 - CONFIG_USBD_PRODUCTID 0xFFFF
1738 - ULPI Layer Support:
1739 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1740 the generic ULPI layer. The generic layer accesses the ULPI PHY
1741 via the platform viewport, so you need both the genric layer and
1742 the viewport enabled. Currently only Chipidea/ARC based
1743 viewport is supported.
1744 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1745 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1746 If your ULPI phy needs a different reference clock than the
1747 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1748 the appropriate value in Hz.
1751 The MMC controller on the Intel PXA is supported. To
1752 enable this define CONFIG_MMC. The MMC can be
1753 accessed from the boot prompt by mapping the device
1754 to physical memory similar to flash. Command line is
1755 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1756 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1759 Support for Renesas on-chip MMCIF controller
1761 CONFIG_SH_MMCIF_ADDR
1762 Define the base address of MMCIF registers
1765 Define the clock frequency for MMCIF
1768 Enable the generic MMC driver
1770 CONFIG_SUPPORT_EMMC_BOOT
1771 Enable some additional features of the eMMC boot partitions.
1773 CONFIG_SUPPORT_EMMC_RPMB
1774 Enable the commands for reading, writing and programming the
1775 key for the Replay Protection Memory Block partition in eMMC.
1777 - USB Device Firmware Update (DFU) class support:
1779 This enables the USB portion of the DFU USB class
1782 This enables the command "dfu" which is used to have
1783 U-Boot create a DFU class device via USB. This command
1784 requires that the "dfu_alt_info" environment variable be
1785 set and define the alt settings to expose to the host.
1788 This enables support for exposing (e)MMC devices via DFU.
1791 This enables support for exposing NAND devices via DFU.
1794 This enables support for exposing RAM via DFU.
1795 Note: DFU spec refer to non-volatile memory usage, but
1796 allow usages beyond the scope of spec - here RAM usage,
1797 one that would help mostly the developer.
1799 CONFIG_SYS_DFU_DATA_BUF_SIZE
1800 Dfu transfer uses a buffer before writing data to the
1801 raw storage device. Make the size (in bytes) of this buffer
1802 configurable. The size of this buffer is also configurable
1803 through the "dfu_bufsiz" environment variable.
1805 CONFIG_SYS_DFU_MAX_FILE_SIZE
1806 When updating files rather than the raw storage device,
1807 we use a static buffer to copy the file into and then write
1808 the buffer once we've been given the whole file. Define
1809 this to the maximum filesize (in bytes) for the buffer.
1810 Default is 4 MiB if undefined.
1812 DFU_DEFAULT_POLL_TIMEOUT
1813 Poll timeout [ms], is the timeout a device can send to the
1814 host. The host must wait for this timeout before sending
1815 a subsequent DFU_GET_STATUS request to the device.
1817 DFU_MANIFEST_POLL_TIMEOUT
1818 Poll timeout [ms], which the device sends to the host when
1819 entering dfuMANIFEST state. Host waits this timeout, before
1820 sending again an USB request to the device.
1822 - USB Device Android Fastboot support:
1824 This enables the command "fastboot" which enables the Android
1825 fastboot mode for the platform's USB device. Fastboot is a USB
1826 protocol for downloading images, flashing and device control
1827 used on Android devices.
1828 See doc/README.android-fastboot for more information.
1830 CONFIG_ANDROID_BOOT_IMAGE
1831 This enables support for booting images which use the Android
1832 image format header.
1834 CONFIG_USB_FASTBOOT_BUF_ADDR
1835 The fastboot protocol requires a large memory buffer for
1836 downloads. Define this to the starting RAM address to use for
1839 CONFIG_USB_FASTBOOT_BUF_SIZE
1840 The fastboot protocol requires a large memory buffer for
1841 downloads. This buffer should be as large as possible for a
1842 platform. Define this to the size available RAM for fastboot.
1844 CONFIG_FASTBOOT_FLASH
1845 The fastboot protocol includes a "flash" command for writing
1846 the downloaded image to a non-volatile storage device. Define
1847 this to enable the "fastboot flash" command.
1849 CONFIG_FASTBOOT_FLASH_MMC_DEV
1850 The fastboot "flash" command requires additional information
1851 regarding the non-volatile storage device. Define this to
1852 the eMMC device that fastboot should use to store the image.
1854 CONFIG_FASTBOOT_GPT_NAME
1855 The fastboot "flash" command supports writing the downloaded
1856 image to the Protective MBR and the Primary GUID Partition
1857 Table. (Additionally, this downloaded image is post-processed
1858 to generate and write the Backup GUID Partition Table.)
1859 This occurs when the specified "partition name" on the
1860 "fastboot flash" command line matches this value.
1861 Default is GPT_ENTRY_NAME (currently "gpt") if undefined.
1863 - Journaling Flash filesystem support:
1864 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1865 CONFIG_JFFS2_NAND_DEV
1866 Define these for a default partition on a NAND device
1868 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1869 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1870 Define these for a default partition on a NOR device
1872 CONFIG_SYS_JFFS_CUSTOM_PART
1873 Define this to create an own partition. You have to provide a
1874 function struct part_info* jffs2_part_info(int part_num)
1876 If you define only one JFFS2 partition you may also want to
1877 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1878 to disable the command chpart. This is the default when you
1879 have not defined a custom partition
1881 - FAT(File Allocation Table) filesystem write function support:
1884 Define this to enable support for saving memory data as a
1885 file in FAT formatted partition.
1887 This will also enable the command "fatwrite" enabling the
1888 user to write files to FAT.
1890 CBFS (Coreboot Filesystem) support
1893 Define this to enable support for reading from a Coreboot
1894 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1897 - FAT(File Allocation Table) filesystem cluster size:
1898 CONFIG_FS_FAT_MAX_CLUSTSIZE
1900 Define the max cluster size for fat operations else
1901 a default value of 65536 will be defined.
1906 Define this to enable standard (PC-Style) keyboard
1910 Standard PC keyboard driver with US (is default) and
1911 GERMAN key layout (switch via environment 'keymap=de') support.
1912 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1913 for cfb_console. Supports cursor blinking.
1916 Enables a Chrome OS keyboard using the CROS_EC interface.
1917 This uses CROS_EC to communicate with a second microcontroller
1918 which provides key scans on request.
1923 Define this to enable video support (for output to
1926 CONFIG_VIDEO_CT69000
1928 Enable Chips & Technologies 69000 Video chip
1930 CONFIG_VIDEO_SMI_LYNXEM
1931 Enable Silicon Motion SMI 712/710/810 Video chip. The
1932 video output is selected via environment 'videoout'
1933 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1936 For the CT69000 and SMI_LYNXEM drivers, videomode is
1937 selected via environment 'videomode'. Two different ways
1939 - "videomode=num" 'num' is a standard LiLo mode numbers.
1940 Following standard modes are supported (* is default):
1942 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1943 -------------+---------------------------------------------
1944 8 bits | 0x301* 0x303 0x305 0x161 0x307
1945 15 bits | 0x310 0x313 0x316 0x162 0x319
1946 16 bits | 0x311 0x314 0x317 0x163 0x31A
1947 24 bits | 0x312 0x315 0x318 ? 0x31B
1948 -------------+---------------------------------------------
1949 (i.e. setenv videomode 317; saveenv; reset;)
1951 - "videomode=bootargs" all the video parameters are parsed
1952 from the bootargs. (See drivers/video/videomodes.c)
1955 CONFIG_VIDEO_SED13806
1956 Enable Epson SED13806 driver. This driver supports 8bpp
1957 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1958 or CONFIG_VIDEO_SED13806_16BPP
1961 Enable the Freescale DIU video driver. Reference boards for
1962 SOCs that have a DIU should define this macro to enable DIU
1963 support, and should also define these other macros:
1969 CONFIG_VIDEO_SW_CURSOR
1970 CONFIG_VGA_AS_SINGLE_DEVICE
1972 CONFIG_VIDEO_BMP_LOGO
1974 The DIU driver will look for the 'video-mode' environment
1975 variable, and if defined, enable the DIU as a console during
1976 boot. See the documentation file README.video for a
1977 description of this variable.
1981 Enable the VGA video / BIOS for x86. The alternative if you
1982 are using coreboot is to use the coreboot frame buffer
1989 Define this to enable a custom keyboard support.
1990 This simply calls drv_keyboard_init() which must be
1991 defined in your board-specific files.
1992 The only board using this so far is RBC823.
1994 - LCD Support: CONFIG_LCD
1996 Define this to enable LCD support (for output to LCD
1997 display); also select one of the supported displays
1998 by defining one of these:
2002 HITACHI TX09D70VM1CCA, 3.5", 240x320.
2004 CONFIG_NEC_NL6448AC33:
2006 NEC NL6448AC33-18. Active, color, single scan.
2008 CONFIG_NEC_NL6448BC20
2010 NEC NL6448BC20-08. 6.5", 640x480.
2011 Active, color, single scan.
2013 CONFIG_NEC_NL6448BC33_54
2015 NEC NL6448BC33-54. 10.4", 640x480.
2016 Active, color, single scan.
2020 Sharp 320x240. Active, color, single scan.
2021 It isn't 16x9, and I am not sure what it is.
2023 CONFIG_SHARP_LQ64D341
2025 Sharp LQ64D341 display, 640x480.
2026 Active, color, single scan.
2030 HLD1045 display, 640x480.
2031 Active, color, single scan.
2035 Optrex CBL50840-2 NF-FW 99 22 M5
2037 Hitachi LMG6912RPFC-00T
2041 320x240. Black & white.
2043 Normally display is black on white background; define
2044 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
2046 CONFIG_LCD_ALIGNMENT
2048 Normally the LCD is page-aligned (typically 4KB). If this is
2049 defined then the LCD will be aligned to this value instead.
2050 For ARM it is sometimes useful to use MMU_SECTION_SIZE
2051 here, since it is cheaper to change data cache settings on
2052 a per-section basis.
2054 CONFIG_CONSOLE_SCROLL_LINES
2056 When the console need to be scrolled, this is the number of
2057 lines to scroll by. It defaults to 1. Increasing this makes
2058 the console jump but can help speed up operation when scrolling
2063 Support drawing of RLE8-compressed bitmaps on the LCD.
2067 Enables an 'i2c edid' command which can read EDID
2068 information over I2C from an attached LCD display.
2070 - Splash Screen Support: CONFIG_SPLASH_SCREEN
2072 If this option is set, the environment is checked for
2073 a variable "splashimage". If found, the usual display
2074 of logo, copyright and system information on the LCD
2075 is suppressed and the BMP image at the address
2076 specified in "splashimage" is loaded instead. The
2077 console is redirected to the "nulldev", too. This
2078 allows for a "silent" boot where a splash screen is
2079 loaded very quickly after power-on.
2081 CONFIG_SPLASHIMAGE_GUARD
2083 If this option is set, then U-Boot will prevent the environment
2084 variable "splashimage" from being set to a problematic address
2085 (see README.displaying-bmps).
2086 This option is useful for targets where, due to alignment
2087 restrictions, an improperly aligned BMP image will cause a data
2088 abort. If you think you will not have problems with unaligned
2089 accesses (for example because your toolchain prevents them)
2090 there is no need to set this option.
2092 CONFIG_SPLASH_SCREEN_ALIGN
2094 If this option is set the splash image can be freely positioned
2095 on the screen. Environment variable "splashpos" specifies the
2096 position as "x,y". If a positive number is given it is used as
2097 number of pixel from left/top. If a negative number is given it
2098 is used as number of pixel from right/bottom. You can also
2099 specify 'm' for centering the image.
2102 setenv splashpos m,m
2103 => image at center of screen
2105 setenv splashpos 30,20
2106 => image at x = 30 and y = 20
2108 setenv splashpos -10,m
2109 => vertically centered image
2110 at x = dspWidth - bmpWidth - 9
2112 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
2114 If this option is set, additionally to standard BMP
2115 images, gzipped BMP images can be displayed via the
2116 splashscreen support or the bmp command.
2118 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
2120 If this option is set, 8-bit RLE compressed BMP images
2121 can be displayed via the splashscreen support or the
2124 - Do compressing for memory range:
2127 If this option is set, it would use zlib deflate method
2128 to compress the specified memory at its best effort.
2130 - Compression support:
2133 Enabled by default to support gzip compressed images.
2137 If this option is set, support for bzip2 compressed
2138 images is included. If not, only uncompressed and gzip
2139 compressed images are supported.
2141 NOTE: the bzip2 algorithm requires a lot of RAM, so
2142 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
2147 If this option is set, support for lzma compressed
2150 Note: The LZMA algorithm adds between 2 and 4KB of code and it
2151 requires an amount of dynamic memory that is given by the
2154 (1846 + 768 << (lc + lp)) * sizeof(uint16)
2156 Where lc and lp stand for, respectively, Literal context bits
2157 and Literal pos bits.
2159 This value is upper-bounded by 14MB in the worst case. Anyway,
2160 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
2161 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
2162 a very small buffer.
2164 Use the lzmainfo tool to determinate the lc and lp values and
2165 then calculate the amount of needed dynamic memory (ensuring
2166 the appropriate CONFIG_SYS_MALLOC_LEN value).
2170 If this option is set, support for LZO compressed images
2176 The address of PHY on MII bus.
2178 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
2180 The clock frequency of the MII bus
2184 If this option is set, support for speed/duplex
2185 detection of gigabit PHY is included.
2187 CONFIG_PHY_RESET_DELAY
2189 Some PHY like Intel LXT971A need extra delay after
2190 reset before any MII register access is possible.
2191 For such PHY, set this option to the usec delay
2192 required. (minimum 300usec for LXT971A)
2194 CONFIG_PHY_CMD_DELAY (ppc4xx)
2196 Some PHY like Intel LXT971A need extra delay after
2197 command issued before MII status register can be read
2207 Define a default value for Ethernet address to use
2208 for the respective Ethernet interface, in case this
2209 is not determined automatically.
2214 Define a default value for the IP address to use for
2215 the default Ethernet interface, in case this is not
2216 determined through e.g. bootp.
2217 (Environment variable "ipaddr")
2219 - Server IP address:
2222 Defines a default value for the IP address of a TFTP
2223 server to contact when using the "tftboot" command.
2224 (Environment variable "serverip")
2226 CONFIG_KEEP_SERVERADDR
2228 Keeps the server's MAC address, in the env 'serveraddr'
2229 for passing to bootargs (like Linux's netconsole option)
2231 - Gateway IP address:
2234 Defines a default value for the IP address of the
2235 default router where packets to other networks are
2237 (Environment variable "gatewayip")
2242 Defines a default value for the subnet mask (or
2243 routing prefix) which is used to determine if an IP
2244 address belongs to the local subnet or needs to be
2245 forwarded through a router.
2246 (Environment variable "netmask")
2248 - Multicast TFTP Mode:
2251 Defines whether you want to support multicast TFTP as per
2252 rfc-2090; for example to work with atftp. Lets lots of targets
2253 tftp down the same boot image concurrently. Note: the Ethernet
2254 driver in use must provide a function: mcast() to join/leave a
2257 - BOOTP Recovery Mode:
2258 CONFIG_BOOTP_RANDOM_DELAY
2260 If you have many targets in a network that try to
2261 boot using BOOTP, you may want to avoid that all
2262 systems send out BOOTP requests at precisely the same
2263 moment (which would happen for instance at recovery
2264 from a power failure, when all systems will try to
2265 boot, thus flooding the BOOTP server. Defining
2266 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2267 inserted before sending out BOOTP requests. The
2268 following delays are inserted then:
2270 1st BOOTP request: delay 0 ... 1 sec
2271 2nd BOOTP request: delay 0 ... 2 sec
2272 3rd BOOTP request: delay 0 ... 4 sec
2274 BOOTP requests: delay 0 ... 8 sec
2276 CONFIG_BOOTP_ID_CACHE_SIZE
2278 BOOTP packets are uniquely identified using a 32-bit ID. The
2279 server will copy the ID from client requests to responses and
2280 U-Boot will use this to determine if it is the destination of
2281 an incoming response. Some servers will check that addresses
2282 aren't in use before handing them out (usually using an ARP
2283 ping) and therefore take up to a few hundred milliseconds to
2284 respond. Network congestion may also influence the time it
2285 takes for a response to make it back to the client. If that
2286 time is too long, U-Boot will retransmit requests. In order
2287 to allow earlier responses to still be accepted after these
2288 retransmissions, U-Boot's BOOTP client keeps a small cache of
2289 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2290 cache. The default is to keep IDs for up to four outstanding
2291 requests. Increasing this will allow U-Boot to accept offers
2292 from a BOOTP client in networks with unusually high latency.
2294 - DHCP Advanced Options:
2295 You can fine tune the DHCP functionality by defining
2296 CONFIG_BOOTP_* symbols:
2298 CONFIG_BOOTP_SUBNETMASK
2299 CONFIG_BOOTP_GATEWAY
2300 CONFIG_BOOTP_HOSTNAME
2301 CONFIG_BOOTP_NISDOMAIN
2302 CONFIG_BOOTP_BOOTPATH
2303 CONFIG_BOOTP_BOOTFILESIZE
2306 CONFIG_BOOTP_SEND_HOSTNAME
2307 CONFIG_BOOTP_NTPSERVER
2308 CONFIG_BOOTP_TIMEOFFSET
2309 CONFIG_BOOTP_VENDOREX
2310 CONFIG_BOOTP_MAY_FAIL
2312 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2313 environment variable, not the BOOTP server.
2315 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2316 after the configured retry count, the call will fail
2317 instead of starting over. This can be used to fail over
2318 to Link-local IP address configuration if the DHCP server
2321 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2322 serverip from a DHCP server, it is possible that more
2323 than one DNS serverip is offered to the client.
2324 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2325 serverip will be stored in the additional environment
2326 variable "dnsip2". The first DNS serverip is always
2327 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2330 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2331 to do a dynamic update of a DNS server. To do this, they
2332 need the hostname of the DHCP requester.
2333 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2334 of the "hostname" environment variable is passed as
2335 option 12 to the DHCP server.
2337 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2339 A 32bit value in microseconds for a delay between
2340 receiving a "DHCP Offer" and sending the "DHCP Request".
2341 This fixes a problem with certain DHCP servers that don't
2342 respond 100% of the time to a "DHCP request". E.g. On an
2343 AT91RM9200 processor running at 180MHz, this delay needed
2344 to be *at least* 15,000 usec before a Windows Server 2003
2345 DHCP server would reply 100% of the time. I recommend at
2346 least 50,000 usec to be safe. The alternative is to hope
2347 that one of the retries will be successful but note that
2348 the DHCP timeout and retry process takes a longer than
2351 - Link-local IP address negotiation:
2352 Negotiate with other link-local clients on the local network
2353 for an address that doesn't require explicit configuration.
2354 This is especially useful if a DHCP server cannot be guaranteed
2355 to exist in all environments that the device must operate.
2357 See doc/README.link-local for more information.
2360 CONFIG_CDP_DEVICE_ID
2362 The device id used in CDP trigger frames.
2364 CONFIG_CDP_DEVICE_ID_PREFIX
2366 A two character string which is prefixed to the MAC address
2371 A printf format string which contains the ascii name of
2372 the port. Normally is set to "eth%d" which sets
2373 eth0 for the first Ethernet, eth1 for the second etc.
2375 CONFIG_CDP_CAPABILITIES
2377 A 32bit integer which indicates the device capabilities;
2378 0x00000010 for a normal host which does not forwards.
2382 An ascii string containing the version of the software.
2386 An ascii string containing the name of the platform.
2390 A 32bit integer sent on the trigger.
2392 CONFIG_CDP_POWER_CONSUMPTION
2394 A 16bit integer containing the power consumption of the
2395 device in .1 of milliwatts.
2397 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2399 A byte containing the id of the VLAN.
2401 - Status LED: CONFIG_STATUS_LED
2403 Several configurations allow to display the current
2404 status using a LED. For instance, the LED will blink
2405 fast while running U-Boot code, stop blinking as
2406 soon as a reply to a BOOTP request was received, and
2407 start blinking slow once the Linux kernel is running
2408 (supported by a status LED driver in the Linux
2409 kernel). Defining CONFIG_STATUS_LED enables this
2415 The status LED can be connected to a GPIO pin.
2416 In such cases, the gpio_led driver can be used as a
2417 status LED backend implementation. Define CONFIG_GPIO_LED
2418 to include the gpio_led driver in the U-Boot binary.
2420 CONFIG_GPIO_LED_INVERTED_TABLE
2421 Some GPIO connected LEDs may have inverted polarity in which
2422 case the GPIO high value corresponds to LED off state and
2423 GPIO low value corresponds to LED on state.
2424 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2425 with a list of GPIO LEDs that have inverted polarity.
2427 - CAN Support: CONFIG_CAN_DRIVER
2429 Defining CONFIG_CAN_DRIVER enables CAN driver support
2430 on those systems that support this (optional)
2431 feature, like the TQM8xxL modules.
2433 - I2C Support: CONFIG_SYS_I2C
2435 This enable the NEW i2c subsystem, and will allow you to use
2436 i2c commands at the u-boot command line (as long as you set
2437 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2438 based realtime clock chips or other i2c devices. See
2439 common/cmd_i2c.c for a description of the command line
2442 ported i2c driver to the new framework:
2443 - drivers/i2c/soft_i2c.c:
2444 - activate first bus with CONFIG_SYS_I2C_SOFT define
2445 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2446 for defining speed and slave address
2447 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2448 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2449 for defining speed and slave address
2450 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2451 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2452 for defining speed and slave address
2453 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2454 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2455 for defining speed and slave address
2457 - drivers/i2c/fsl_i2c.c:
2458 - activate i2c driver with CONFIG_SYS_I2C_FSL
2459 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2460 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2461 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2463 - If your board supports a second fsl i2c bus, define
2464 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2465 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2466 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2469 - drivers/i2c/tegra_i2c.c:
2470 - activate this driver with CONFIG_SYS_I2C_TEGRA
2471 - This driver adds 4 i2c buses with a fix speed from
2472 100000 and the slave addr 0!
2474 - drivers/i2c/ppc4xx_i2c.c
2475 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2476 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2477 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2479 - drivers/i2c/i2c_mxc.c
2480 - activate this driver with CONFIG_SYS_I2C_MXC
2481 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2482 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2483 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2484 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2485 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2486 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2487 If those defines are not set, default value is 100000
2488 for speed, and 0 for slave.
2490 - drivers/i2c/rcar_i2c.c:
2491 - activate this driver with CONFIG_SYS_I2C_RCAR
2492 - This driver adds 4 i2c buses
2494 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2495 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2496 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2497 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2498 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2499 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2500 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2501 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2502 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2504 - drivers/i2c/sh_i2c.c:
2505 - activate this driver with CONFIG_SYS_I2C_SH
2506 - This driver adds from 2 to 5 i2c buses
2508 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2509 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2510 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2511 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2512 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2513 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2514 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2515 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2516 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2517 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2518 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2519 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2520 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2522 - drivers/i2c/omap24xx_i2c.c
2523 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2524 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2525 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2526 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2527 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2528 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2529 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2530 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2531 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2532 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2533 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2535 - drivers/i2c/zynq_i2c.c
2536 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2537 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2538 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2540 - drivers/i2c/s3c24x0_i2c.c:
2541 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2542 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2543 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2544 with a fix speed from 100000 and the slave addr 0!
2546 - drivers/i2c/ihs_i2c.c
2547 - activate this driver with CONFIG_SYS_I2C_IHS
2548 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2549 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2550 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2551 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2552 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2553 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2554 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2555 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2556 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2557 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2558 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2559 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2563 CONFIG_SYS_NUM_I2C_BUSES
2564 Hold the number of i2c buses you want to use. If you
2565 don't use/have i2c muxes on your i2c bus, this
2566 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2569 CONFIG_SYS_I2C_DIRECT_BUS
2570 define this, if you don't use i2c muxes on your hardware.
2571 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2574 CONFIG_SYS_I2C_MAX_HOPS
2575 define how many muxes are maximal consecutively connected
2576 on one i2c bus. If you not use i2c muxes, omit this
2579 CONFIG_SYS_I2C_BUSES
2580 hold a list of buses you want to use, only used if
2581 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2582 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2583 CONFIG_SYS_NUM_I2C_BUSES = 9:
2585 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2586 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2587 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2588 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2589 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2590 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2591 {1, {I2C_NULL_HOP}}, \
2592 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2593 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2597 bus 0 on adapter 0 without a mux
2598 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2599 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2600 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2601 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2602 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2603 bus 6 on adapter 1 without a mux
2604 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2605 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2607 If you do not have i2c muxes on your board, omit this define.
2609 - Legacy I2C Support: CONFIG_HARD_I2C
2611 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2612 provides the following compelling advantages:
2614 - more than one i2c adapter is usable
2615 - approved multibus support
2616 - better i2c mux support
2618 ** Please consider updating your I2C driver now. **
2620 These enable legacy I2C serial bus commands. Defining
2621 CONFIG_HARD_I2C will include the appropriate I2C driver
2622 for the selected CPU.
2624 This will allow you to use i2c commands at the u-boot
2625 command line (as long as you set CONFIG_CMD_I2C in
2626 CONFIG_COMMANDS) and communicate with i2c based realtime
2627 clock chips. See common/cmd_i2c.c for a description of the
2628 command line interface.
2630 CONFIG_HARD_I2C selects a hardware I2C controller.
2632 There are several other quantities that must also be
2633 defined when you define CONFIG_HARD_I2C.
2635 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2636 to be the frequency (in Hz) at which you wish your i2c bus
2637 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2638 the CPU's i2c node address).
2640 Now, the u-boot i2c code for the mpc8xx
2641 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2642 and so its address should therefore be cleared to 0 (See,
2643 eg, MPC823e User's Manual p.16-473). So, set
2644 CONFIG_SYS_I2C_SLAVE to 0.
2646 CONFIG_SYS_I2C_INIT_MPC5XXX
2648 When a board is reset during an i2c bus transfer
2649 chips might think that the current transfer is still
2650 in progress. Reset the slave devices by sending start
2651 commands until the slave device responds.
2653 That's all that's required for CONFIG_HARD_I2C.
2655 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2656 then the following macros need to be defined (examples are
2657 from include/configs/lwmon.h):
2661 (Optional). Any commands necessary to enable the I2C
2662 controller or configure ports.
2664 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2668 (Only for MPC8260 CPU). The I/O port to use (the code
2669 assumes both bits are on the same port). Valid values
2670 are 0..3 for ports A..D.
2674 The code necessary to make the I2C data line active
2675 (driven). If the data line is open collector, this
2678 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2682 The code necessary to make the I2C data line tri-stated
2683 (inactive). If the data line is open collector, this
2686 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2690 Code that returns true if the I2C data line is high,
2693 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2697 If <bit> is true, sets the I2C data line high. If it
2698 is false, it clears it (low).
2700 eg: #define I2C_SDA(bit) \
2701 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2702 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2706 If <bit> is true, sets the I2C clock line high. If it
2707 is false, it clears it (low).
2709 eg: #define I2C_SCL(bit) \
2710 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2711 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2715 This delay is invoked four times per clock cycle so this
2716 controls the rate of data transfer. The data rate thus
2717 is 1 / (I2C_DELAY * 4). Often defined to be something
2720 #define I2C_DELAY udelay(2)
2722 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2724 If your arch supports the generic GPIO framework (asm/gpio.h),
2725 then you may alternatively define the two GPIOs that are to be
2726 used as SCL / SDA. Any of the previous I2C_xxx macros will
2727 have GPIO-based defaults assigned to them as appropriate.
2729 You should define these to the GPIO value as given directly to
2730 the generic GPIO functions.
2732 CONFIG_SYS_I2C_INIT_BOARD
2734 When a board is reset during an i2c bus transfer
2735 chips might think that the current transfer is still
2736 in progress. On some boards it is possible to access
2737 the i2c SCLK line directly, either by using the
2738 processor pin as a GPIO or by having a second pin
2739 connected to the bus. If this option is defined a
2740 custom i2c_init_board() routine in boards/xxx/board.c
2741 is run early in the boot sequence.
2743 CONFIG_SYS_I2C_BOARD_LATE_INIT
2745 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2746 defined a custom i2c_board_late_init() routine in
2747 boards/xxx/board.c is run AFTER the operations in i2c_init()
2748 is completed. This callpoint can be used to unreset i2c bus
2749 using CPU i2c controller register accesses for CPUs whose i2c
2750 controller provide such a method. It is called at the end of
2751 i2c_init() to allow i2c_init operations to setup the i2c bus
2752 controller on the CPU (e.g. setting bus speed & slave address).
2754 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2756 This option enables configuration of bi_iic_fast[] flags
2757 in u-boot bd_info structure based on u-boot environment
2758 variable "i2cfast". (see also i2cfast)
2760 CONFIG_I2C_MULTI_BUS
2762 This option allows the use of multiple I2C buses, each of which
2763 must have a controller. At any point in time, only one bus is
2764 active. To switch to a different bus, use the 'i2c dev' command.
2765 Note that bus numbering is zero-based.
2767 CONFIG_SYS_I2C_NOPROBES
2769 This option specifies a list of I2C devices that will be skipped
2770 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2771 is set, specify a list of bus-device pairs. Otherwise, specify
2772 a 1D array of device addresses
2775 #undef CONFIG_I2C_MULTI_BUS
2776 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2778 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2780 #define CONFIG_I2C_MULTI_BUS
2781 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2783 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2785 CONFIG_SYS_SPD_BUS_NUM
2787 If defined, then this indicates the I2C bus number for DDR SPD.
2788 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2790 CONFIG_SYS_RTC_BUS_NUM
2792 If defined, then this indicates the I2C bus number for the RTC.
2793 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2795 CONFIG_SYS_DTT_BUS_NUM
2797 If defined, then this indicates the I2C bus number for the DTT.
2798 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2800 CONFIG_SYS_I2C_DTT_ADDR:
2802 If defined, specifies the I2C address of the DTT device.
2803 If not defined, then U-Boot uses predefined value for
2804 specified DTT device.
2806 CONFIG_SOFT_I2C_READ_REPEATED_START
2808 defining this will force the i2c_read() function in
2809 the soft_i2c driver to perform an I2C repeated start
2810 between writing the address pointer and reading the
2811 data. If this define is omitted the default behaviour
2812 of doing a stop-start sequence will be used. Most I2C
2813 devices can use either method, but some require one or
2816 - SPI Support: CONFIG_SPI
2818 Enables SPI driver (so far only tested with
2819 SPI EEPROM, also an instance works with Crystal A/D and
2820 D/As on the SACSng board)
2824 Enables the driver for SPI controller on SuperH. Currently
2825 only SH7757 is supported.
2829 Enables extended (16-bit) SPI EEPROM addressing.
2830 (symmetrical to CONFIG_I2C_X)
2834 Enables a software (bit-bang) SPI driver rather than
2835 using hardware support. This is a general purpose
2836 driver that only requires three general I/O port pins
2837 (two outputs, one input) to function. If this is
2838 defined, the board configuration must define several
2839 SPI configuration items (port pins to use, etc). For
2840 an example, see include/configs/sacsng.h.
2844 Enables a hardware SPI driver for general-purpose reads
2845 and writes. As with CONFIG_SOFT_SPI, the board configuration
2846 must define a list of chip-select function pointers.
2847 Currently supported on some MPC8xxx processors. For an
2848 example, see include/configs/mpc8349emds.h.
2852 Enables the driver for the SPI controllers on i.MX and MXC
2853 SoCs. Currently i.MX31/35/51 are supported.
2855 CONFIG_SYS_SPI_MXC_WAIT
2856 Timeout for waiting until spi transfer completed.
2857 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2859 - FPGA Support: CONFIG_FPGA
2861 Enables FPGA subsystem.
2863 CONFIG_FPGA_<vendor>
2865 Enables support for specific chip vendors.
2868 CONFIG_FPGA_<family>
2870 Enables support for FPGA family.
2871 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2875 Specify the number of FPGA devices to support.
2877 CONFIG_CMD_FPGA_LOADMK
2879 Enable support for fpga loadmk command
2881 CONFIG_CMD_FPGA_LOADP
2883 Enable support for fpga loadp command - load partial bitstream
2885 CONFIG_CMD_FPGA_LOADBP
2887 Enable support for fpga loadbp command - load partial bitstream
2890 CONFIG_SYS_FPGA_PROG_FEEDBACK
2892 Enable printing of hash marks during FPGA configuration.
2894 CONFIG_SYS_FPGA_CHECK_BUSY
2896 Enable checks on FPGA configuration interface busy
2897 status by the configuration function. This option
2898 will require a board or device specific function to
2903 If defined, a function that provides delays in the FPGA
2904 configuration driver.
2906 CONFIG_SYS_FPGA_CHECK_CTRLC
2907 Allow Control-C to interrupt FPGA configuration
2909 CONFIG_SYS_FPGA_CHECK_ERROR
2911 Check for configuration errors during FPGA bitfile
2912 loading. For example, abort during Virtex II
2913 configuration if the INIT_B line goes low (which
2914 indicated a CRC error).
2916 CONFIG_SYS_FPGA_WAIT_INIT
2918 Maximum time to wait for the INIT_B line to de-assert
2919 after PROB_B has been de-asserted during a Virtex II
2920 FPGA configuration sequence. The default time is 500
2923 CONFIG_SYS_FPGA_WAIT_BUSY
2925 Maximum time to wait for BUSY to de-assert during
2926 Virtex II FPGA configuration. The default is 5 ms.
2928 CONFIG_SYS_FPGA_WAIT_CONFIG
2930 Time to wait after FPGA configuration. The default is
2933 - Configuration Management:
2936 Some SoCs need special image types (e.g. U-Boot binary
2937 with a special header) as build targets. By defining
2938 CONFIG_BUILD_TARGET in the SoC / board header, this
2939 special image will be automatically built upon calling
2944 If defined, this string will be added to the U-Boot
2945 version information (U_BOOT_VERSION)
2947 - Vendor Parameter Protection:
2949 U-Boot considers the values of the environment
2950 variables "serial#" (Board Serial Number) and
2951 "ethaddr" (Ethernet Address) to be parameters that
2952 are set once by the board vendor / manufacturer, and
2953 protects these variables from casual modification by
2954 the user. Once set, these variables are read-only,
2955 and write or delete attempts are rejected. You can
2956 change this behaviour:
2958 If CONFIG_ENV_OVERWRITE is #defined in your config
2959 file, the write protection for vendor parameters is
2960 completely disabled. Anybody can change or delete
2963 Alternatively, if you #define _both_ CONFIG_ETHADDR
2964 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2965 Ethernet address is installed in the environment,
2966 which can be changed exactly ONCE by the user. [The
2967 serial# is unaffected by this, i. e. it remains
2970 The same can be accomplished in a more flexible way
2971 for any variable by configuring the type of access
2972 to allow for those variables in the ".flags" variable
2973 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2978 Define this variable to enable the reservation of
2979 "protected RAM", i. e. RAM which is not overwritten
2980 by U-Boot. Define CONFIG_PRAM to hold the number of
2981 kB you want to reserve for pRAM. You can overwrite
2982 this default value by defining an environment
2983 variable "pram" to the number of kB you want to
2984 reserve. Note that the board info structure will
2985 still show the full amount of RAM. If pRAM is
2986 reserved, a new environment variable "mem" will
2987 automatically be defined to hold the amount of
2988 remaining RAM in a form that can be passed as boot
2989 argument to Linux, for instance like that:
2991 setenv bootargs ... mem=\${mem}
2994 This way you can tell Linux not to use this memory,
2995 either, which results in a memory region that will
2996 not be affected by reboots.
2998 *WARNING* If your board configuration uses automatic
2999 detection of the RAM size, you must make sure that
3000 this memory test is non-destructive. So far, the
3001 following board configurations are known to be
3004 IVMS8, IVML24, SPD8xx, TQM8xxL,
3005 HERMES, IP860, RPXlite, LWMON,
3008 - Access to physical memory region (> 4GB)
3009 Some basic support is provided for operations on memory not
3010 normally accessible to U-Boot - e.g. some architectures
3011 support access to more than 4GB of memory on 32-bit
3012 machines using physical address extension or similar.
3013 Define CONFIG_PHYSMEM to access this basic support, which
3014 currently only supports clearing the memory.
3019 Define this variable to stop the system in case of a
3020 fatal error, so that you have to reset it manually.
3021 This is probably NOT a good idea for an embedded
3022 system where you want the system to reboot
3023 automatically as fast as possible, but it may be
3024 useful during development since you can try to debug
3025 the conditions that lead to the situation.
3027 CONFIG_NET_RETRY_COUNT
3029 This variable defines the number of retries for
3030 network operations like ARP, RARP, TFTP, or BOOTP
3031 before giving up the operation. If not defined, a
3032 default value of 5 is used.
3036 Timeout waiting for an ARP reply in milliseconds.
3040 Timeout in milliseconds used in NFS protocol.
3041 If you encounter "ERROR: Cannot umount" in nfs command,
3042 try longer timeout such as
3043 #define CONFIG_NFS_TIMEOUT 10000UL
3045 - Command Interpreter:
3046 CONFIG_AUTO_COMPLETE
3048 Enable auto completion of commands using TAB.
3050 CONFIG_SYS_PROMPT_HUSH_PS2
3052 This defines the secondary prompt string, which is
3053 printed when the command interpreter needs more input
3054 to complete a command. Usually "> ".
3058 In the current implementation, the local variables
3059 space and global environment variables space are
3060 separated. Local variables are those you define by
3061 simply typing `name=value'. To access a local
3062 variable later on, you have write `$name' or
3063 `${name}'; to execute the contents of a variable
3064 directly type `$name' at the command prompt.
3066 Global environment variables are those you use
3067 setenv/printenv to work with. To run a command stored
3068 in such a variable, you need to use the run command,
3069 and you must not use the '$' sign to access them.
3071 To store commands and special characters in a
3072 variable, please use double quotation marks
3073 surrounding the whole text of the variable, instead
3074 of the backslashes before semicolons and special
3077 - Command Line Editing and History:
3078 CONFIG_CMDLINE_EDITING
3080 Enable editing and History functions for interactive
3081 command line input operations
3083 - Default Environment:
3084 CONFIG_EXTRA_ENV_SETTINGS
3086 Define this to contain any number of null terminated
3087 strings (variable = value pairs) that will be part of
3088 the default environment compiled into the boot image.
3090 For example, place something like this in your
3091 board's config file:
3093 #define CONFIG_EXTRA_ENV_SETTINGS \
3097 Warning: This method is based on knowledge about the
3098 internal format how the environment is stored by the
3099 U-Boot code. This is NOT an official, exported
3100 interface! Although it is unlikely that this format
3101 will change soon, there is no guarantee either.
3102 You better know what you are doing here.
3104 Note: overly (ab)use of the default environment is
3105 discouraged. Make sure to check other ways to preset
3106 the environment like the "source" command or the
3109 CONFIG_ENV_VARS_UBOOT_CONFIG
3111 Define this in order to add variables describing the
3112 U-Boot build configuration to the default environment.
3113 These will be named arch, cpu, board, vendor, and soc.
3115 Enabling this option will cause the following to be defined:
3123 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
3125 Define this in order to add variables describing certain
3126 run-time determined information about the hardware to the
3127 environment. These will be named board_name, board_rev.
3129 CONFIG_DELAY_ENVIRONMENT
3131 Normally the environment is loaded when the board is
3132 initialised so that it is available to U-Boot. This inhibits
3133 that so that the environment is not available until
3134 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
3135 this is instead controlled by the value of
3136 /config/load-environment.
3138 - DataFlash Support:
3139 CONFIG_HAS_DATAFLASH
3141 Defining this option enables DataFlash features and
3142 allows to read/write in Dataflash via the standard
3145 - Serial Flash support
3148 Defining this option enables SPI flash commands
3149 'sf probe/read/write/erase/update'.
3151 Usage requires an initial 'probe' to define the serial
3152 flash parameters, followed by read/write/erase/update
3155 The following defaults may be provided by the platform
3156 to handle the common case when only a single serial
3157 flash is present on the system.
3159 CONFIG_SF_DEFAULT_BUS Bus identifier
3160 CONFIG_SF_DEFAULT_CS Chip-select
3161 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
3162 CONFIG_SF_DEFAULT_SPEED in Hz
3166 Define this option to include a destructive SPI flash
3169 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
3171 Define this option to use the Bank addr/Extended addr
3172 support on SPI flashes which has size > 16Mbytes.
3174 CONFIG_SF_DUAL_FLASH Dual flash memories
3176 Define this option to use dual flash support where two flash
3177 memories can be connected with a given cs line.
3178 Currently Xilinx Zynq qspi supports these type of connections.
3180 CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
3181 enable the W#/Vpp signal to disable writing to the status
3182 register on ST MICRON flashes like the N25Q128.
3183 The status register write enable/disable bit, combined with
3184 the W#/VPP signal provides hardware data protection for the
3185 device as follows: When the enable/disable bit is set to 1,
3186 and the W#/VPP signal is driven LOW, the status register
3187 nonvolatile bits become read-only and the WRITE STATUS REGISTER
3188 operation will not execute. The only way to exit this
3189 hardware-protected mode is to drive W#/VPP HIGH.
3191 - SystemACE Support:
3194 Adding this option adds support for Xilinx SystemACE
3195 chips attached via some sort of local bus. The address
3196 of the chip must also be defined in the
3197 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
3199 #define CONFIG_SYSTEMACE
3200 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
3202 When SystemACE support is added, the "ace" device type
3203 becomes available to the fat commands, i.e. fatls.
3205 - TFTP Fixed UDP Port:
3208 If this is defined, the environment variable tftpsrcp
3209 is used to supply the TFTP UDP source port value.
3210 If tftpsrcp isn't defined, the normal pseudo-random port
3211 number generator is used.
3213 Also, the environment variable tftpdstp is used to supply
3214 the TFTP UDP destination port value. If tftpdstp isn't
3215 defined, the normal port 69 is used.
3217 The purpose for tftpsrcp is to allow a TFTP server to
3218 blindly start the TFTP transfer using the pre-configured
3219 target IP address and UDP port. This has the effect of
3220 "punching through" the (Windows XP) firewall, allowing
3221 the remainder of the TFTP transfer to proceed normally.
3222 A better solution is to properly configure the firewall,
3223 but sometimes that is not allowed.
3228 This enables a generic 'hash' command which can produce
3229 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3233 Enable the hash verify command (hash -v). This adds to code
3236 CONFIG_SHA1 - This option enables support of hashing using SHA1
3237 algorithm. The hash is calculated in software.
3238 CONFIG_SHA256 - This option enables support of hashing using
3239 SHA256 algorithm. The hash is calculated in software.
3240 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3241 for SHA1/SHA256 hashing.
3242 This affects the 'hash' command and also the
3243 hash_lookup_algo() function.
3244 CONFIG_SHA_PROG_HW_ACCEL - This option enables
3245 hardware-acceleration for SHA1/SHA256 progressive hashing.
3246 Data can be streamed in a block at a time and the hashing
3247 is performed in hardware.
3249 Note: There is also a sha1sum command, which should perhaps
3250 be deprecated in favour of 'hash sha1'.
3252 - Freescale i.MX specific commands:
3253 CONFIG_CMD_HDMIDETECT
3254 This enables 'hdmidet' command which returns true if an
3255 HDMI monitor is detected. This command is i.MX 6 specific.
3258 This enables the 'bmode' (bootmode) command for forcing
3259 a boot from specific media.
3261 This is useful for forcing the ROM's usb downloader to
3262 activate upon a watchdog reset which is nice when iterating
3263 on U-Boot. Using the reset button or running bmode normal
3264 will set it back to normal. This command currently
3265 supports i.MX53 and i.MX6.
3270 This enables the RSA algorithm used for FIT image verification
3271 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
3273 The Modular Exponentiation algorithm in RSA is implemented using
3274 driver model. So CONFIG_DM needs to be enabled by default for this
3275 library to function.
3277 The signing part is build into mkimage regardless of this
3278 option. The software based modular exponentiation is built into
3279 mkimage irrespective of this option.
3281 - bootcount support:
3282 CONFIG_BOOTCOUNT_LIMIT
3284 This enables the bootcounter support, see:
3285 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3288 enable special bootcounter support on at91sam9xe based boards.
3290 enable special bootcounter support on blackfin based boards.
3292 enable special bootcounter support on da850 based boards.
3293 CONFIG_BOOTCOUNT_RAM
3294 enable support for the bootcounter in RAM
3295 CONFIG_BOOTCOUNT_I2C
3296 enable support for the bootcounter on an i2c (like RTC) device.
3297 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3298 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3300 CONFIG_BOOTCOUNT_ALEN = address len
3302 - Show boot progress:
3303 CONFIG_SHOW_BOOT_PROGRESS
3305 Defining this option allows to add some board-
3306 specific code (calling a user-provided function
3307 "show_boot_progress(int)") that enables you to show
3308 the system's boot progress on some display (for
3309 example, some LED's) on your board. At the moment,
3310 the following checkpoints are implemented:
3312 - Detailed boot stage timing
3314 Define this option to get detailed timing of each stage
3315 of the boot process.
3317 CONFIG_BOOTSTAGE_USER_COUNT
3318 This is the number of available user bootstage records.
3319 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3320 a new ID will be allocated from this stash. If you exceed
3321 the limit, recording will stop.
3323 CONFIG_BOOTSTAGE_REPORT
3324 Define this to print a report before boot, similar to this:
3326 Timer summary in microseconds:
3329 3,575,678 3,575,678 board_init_f start
3330 3,575,695 17 arch_cpu_init A9
3331 3,575,777 82 arch_cpu_init done
3332 3,659,598 83,821 board_init_r start
3333 3,910,375 250,777 main_loop
3334 29,916,167 26,005,792 bootm_start
3335 30,361,327 445,160 start_kernel
3337 CONFIG_CMD_BOOTSTAGE
3338 Add a 'bootstage' command which supports printing a report
3339 and un/stashing of bootstage data.
3341 CONFIG_BOOTSTAGE_FDT
3342 Stash the bootstage information in the FDT. A root 'bootstage'
3343 node is created with each bootstage id as a child. Each child
3344 has a 'name' property and either 'mark' containing the
3345 mark time in microsecond, or 'accum' containing the
3346 accumulated time for that bootstage id in microseconds.
3351 name = "board_init_f";
3360 Code in the Linux kernel can find this in /proc/devicetree.
3362 Legacy uImage format:
3365 1 common/cmd_bootm.c before attempting to boot an image
3366 -1 common/cmd_bootm.c Image header has bad magic number
3367 2 common/cmd_bootm.c Image header has correct magic number
3368 -2 common/cmd_bootm.c Image header has bad checksum
3369 3 common/cmd_bootm.c Image header has correct checksum
3370 -3 common/cmd_bootm.c Image data has bad checksum
3371 4 common/cmd_bootm.c Image data has correct checksum
3372 -4 common/cmd_bootm.c Image is for unsupported architecture
3373 5 common/cmd_bootm.c Architecture check OK
3374 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3375 6 common/cmd_bootm.c Image Type check OK
3376 -6 common/cmd_bootm.c gunzip uncompression error
3377 -7 common/cmd_bootm.c Unimplemented compression type
3378 7 common/cmd_bootm.c Uncompression OK
3379 8 common/cmd_bootm.c No uncompress/copy overwrite error
3380 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3382 9 common/image.c Start initial ramdisk verification
3383 -10 common/image.c Ramdisk header has bad magic number
3384 -11 common/image.c Ramdisk header has bad checksum
3385 10 common/image.c Ramdisk header is OK
3386 -12 common/image.c Ramdisk data has bad checksum
3387 11 common/image.c Ramdisk data has correct checksum
3388 12 common/image.c Ramdisk verification complete, start loading
3389 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3390 13 common/image.c Start multifile image verification
3391 14 common/image.c No initial ramdisk, no multifile, continue.
3393 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3395 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3396 -31 post/post.c POST test failed, detected by post_output_backlog()
3397 -32 post/post.c POST test failed, detected by post_run_single()
3399 34 common/cmd_doc.c before loading a Image from a DOC device
3400 -35 common/cmd_doc.c Bad usage of "doc" command
3401 35 common/cmd_doc.c correct usage of "doc" command
3402 -36 common/cmd_doc.c No boot device
3403 36 common/cmd_doc.c correct boot device
3404 -37 common/cmd_doc.c Unknown Chip ID on boot device
3405 37 common/cmd_doc.c correct chip ID found, device available
3406 -38 common/cmd_doc.c Read Error on boot device
3407 38 common/cmd_doc.c reading Image header from DOC device OK
3408 -39 common/cmd_doc.c Image header has bad magic number
3409 39 common/cmd_doc.c Image header has correct magic number
3410 -40 common/cmd_doc.c Error reading Image from DOC device
3411 40 common/cmd_doc.c Image header has correct magic number
3412 41 common/cmd_ide.c before loading a Image from a IDE device
3413 -42 common/cmd_ide.c Bad usage of "ide" command
3414 42 common/cmd_ide.c correct usage of "ide" command
3415 -43 common/cmd_ide.c No boot device
3416 43 common/cmd_ide.c boot device found
3417 -44 common/cmd_ide.c Device not available
3418 44 common/cmd_ide.c Device available
3419 -45 common/cmd_ide.c wrong partition selected
3420 45 common/cmd_ide.c partition selected
3421 -46 common/cmd_ide.c Unknown partition table
3422 46 common/cmd_ide.c valid partition table found
3423 -47 common/cmd_ide.c Invalid partition type
3424 47 common/cmd_ide.c correct partition type
3425 -48 common/cmd_ide.c Error reading Image Header on boot device
3426 48 common/cmd_ide.c reading Image Header from IDE device OK
3427 -49 common/cmd_ide.c Image header has bad magic number
3428 49 common/cmd_ide.c Image header has correct magic number
3429 -50 common/cmd_ide.c Image header has bad checksum
3430 50 common/cmd_ide.c Image header has correct checksum
3431 -51 common/cmd_ide.c Error reading Image from IDE device
3432 51 common/cmd_ide.c reading Image from IDE device OK
3433 52 common/cmd_nand.c before loading a Image from a NAND device
3434 -53 common/cmd_nand.c Bad usage of "nand" command
3435 53 common/cmd_nand.c correct usage of "nand" command
3436 -54 common/cmd_nand.c No boot device
3437 54 common/cmd_nand.c boot device found
3438 -55 common/cmd_nand.c Unknown Chip ID on boot device
3439 55 common/cmd_nand.c correct chip ID found, device available
3440 -56 common/cmd_nand.c Error reading Image Header on boot device
3441 56 common/cmd_nand.c reading Image Header from NAND device OK
3442 -57 common/cmd_nand.c Image header has bad magic number
3443 57 common/cmd_nand.c Image header has correct magic number
3444 -58 common/cmd_nand.c Error reading Image from NAND device
3445 58 common/cmd_nand.c reading Image from NAND device OK
3447 -60 common/env_common.c Environment has a bad CRC, using default
3449 64 net/eth.c starting with Ethernet configuration.
3450 -64 net/eth.c no Ethernet found.
3451 65 net/eth.c Ethernet found.
3453 -80 common/cmd_net.c usage wrong
3454 80 common/cmd_net.c before calling NetLoop()
3455 -81 common/cmd_net.c some error in NetLoop() occurred
3456 81 common/cmd_net.c NetLoop() back without error
3457 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3458 82 common/cmd_net.c trying automatic boot
3459 83 common/cmd_net.c running "source" command
3460 -83 common/cmd_net.c some error in automatic boot or "source" command
3461 84 common/cmd_net.c end without errors
3466 100 common/cmd_bootm.c Kernel FIT Image has correct format
3467 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3468 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3469 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3470 102 common/cmd_bootm.c Kernel unit name specified
3471 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3472 103 common/cmd_bootm.c Found configuration node
3473 104 common/cmd_bootm.c Got kernel subimage node offset
3474 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3475 105 common/cmd_bootm.c Kernel subimage hash verification OK
3476 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3477 106 common/cmd_bootm.c Architecture check OK
3478 -106 common/cmd_bootm.c Kernel subimage has wrong type
3479 107 common/cmd_bootm.c Kernel subimage type OK
3480 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3481 108 common/cmd_bootm.c Got kernel subimage data/size
3482 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3483 -109 common/cmd_bootm.c Can't get kernel subimage type
3484 -110 common/cmd_bootm.c Can't get kernel subimage comp
3485 -111 common/cmd_bootm.c Can't get kernel subimage os
3486 -112 common/cmd_bootm.c Can't get kernel subimage load address
3487 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3489 120 common/image.c Start initial ramdisk verification
3490 -120 common/image.c Ramdisk FIT image has incorrect format
3491 121 common/image.c Ramdisk FIT image has correct format
3492 122 common/image.c No ramdisk subimage unit name, using configuration
3493 -122 common/image.c Can't get configuration for ramdisk subimage
3494 123 common/image.c Ramdisk unit name specified
3495 -124 common/image.c Can't get ramdisk subimage node offset
3496 125 common/image.c Got ramdisk subimage node offset
3497 -125 common/image.c Ramdisk subimage hash verification failed
3498 126 common/image.c Ramdisk subimage hash verification OK
3499 -126 common/image.c Ramdisk subimage for unsupported architecture
3500 127 common/image.c Architecture check OK
3501 -127 common/image.c Can't get ramdisk subimage data/size
3502 128 common/image.c Got ramdisk subimage data/size
3503 129 common/image.c Can't get ramdisk load address
3504 -129 common/image.c Got ramdisk load address
3506 -130 common/cmd_doc.c Incorrect FIT image format
3507 131 common/cmd_doc.c FIT image format OK
3509 -140 common/cmd_ide.c Incorrect FIT image format
3510 141 common/cmd_ide.c FIT image format OK
3512 -150 common/cmd_nand.c Incorrect FIT image format
3513 151 common/cmd_nand.c FIT image format OK
3515 - legacy image format:
3516 CONFIG_IMAGE_FORMAT_LEGACY
3517 enables the legacy image format support in U-Boot.
3520 enabled if CONFIG_FIT_SIGNATURE is not defined.
3522 CONFIG_DISABLE_IMAGE_LEGACY
3523 disable the legacy image format
3525 This define is introduced, as the legacy image format is
3526 enabled per default for backward compatibility.
3528 - FIT image support:
3530 Enable support for the FIT uImage format.
3532 CONFIG_FIT_BEST_MATCH
3533 When no configuration is explicitly selected, default to the
3534 one whose fdt's compatibility field best matches that of
3535 U-Boot itself. A match is considered "best" if it matches the
3536 most specific compatibility entry of U-Boot's fdt's root node.
3537 The order of entries in the configuration's fdt is ignored.
3539 CONFIG_FIT_SIGNATURE
3540 This option enables signature verification of FIT uImages,
3541 using a hash signed and verified using RSA. If
3542 CONFIG_SHA_PROG_HW_ACCEL is defined, i.e support for progressive
3543 hashing is available using hardware, RSA library will use it.
3544 See doc/uImage.FIT/signature.txt for more details.
3546 WARNING: When relying on signed FIT images with required
3547 signature check the legacy image format is default
3548 disabled. If a board need legacy image format support
3549 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3551 CONFIG_FIT_DISABLE_SHA256
3552 Supporting SHA256 hashes has quite an impact on binary size.
3553 For constrained systems sha256 hash support can be disabled
3556 - Standalone program support:
3557 CONFIG_STANDALONE_LOAD_ADDR
3559 This option defines a board specific value for the
3560 address where standalone program gets loaded, thus
3561 overwriting the architecture dependent default
3564 - Frame Buffer Address:
3567 Define CONFIG_FB_ADDR if you want to use specific
3568 address for frame buffer. This is typically the case
3569 when using a graphics controller has separate video
3570 memory. U-Boot will then place the frame buffer at
3571 the given address instead of dynamically reserving it
3572 in system RAM by calling lcd_setmem(), which grabs
3573 the memory for the frame buffer depending on the
3574 configured panel size.
3576 Please see board_init_f function.
3578 - Automatic software updates via TFTP server
3580 CONFIG_UPDATE_TFTP_CNT_MAX
3581 CONFIG_UPDATE_TFTP_MSEC_MAX
3583 These options enable and control the auto-update feature;
3584 for a more detailed description refer to doc/README.update.
3586 - MTD Support (mtdparts command, UBI support)
3589 Adds the MTD device infrastructure from the Linux kernel.
3590 Needed for mtdparts command support.
3592 CONFIG_MTD_PARTITIONS
3594 Adds the MTD partitioning infrastructure from the Linux
3595 kernel. Needed for UBI support.
3597 CONFIG_MTD_NAND_VERIFY_WRITE
3598 verify if the written data is correct reread.
3603 Adds commands for interacting with MTD partitions formatted
3604 with the UBI flash translation layer
3606 Requires also defining CONFIG_RBTREE
3608 CONFIG_UBI_SILENCE_MSG
3610 Make the verbose messages from UBI stop printing. This leaves
3611 warnings and errors enabled.
3614 CONFIG_MTD_UBI_WL_THRESHOLD
3615 This parameter defines the maximum difference between the highest
3616 erase counter value and the lowest erase counter value of eraseblocks
3617 of UBI devices. When this threshold is exceeded, UBI starts performing
3618 wear leveling by means of moving data from eraseblock with low erase
3619 counter to eraseblocks with high erase counter.
3621 The default value should be OK for SLC NAND flashes, NOR flashes and
3622 other flashes which have eraseblock life-cycle 100000 or more.
3623 However, in case of MLC NAND flashes which typically have eraseblock
3624 life-cycle less than 10000, the threshold should be lessened (e.g.,
3625 to 128 or 256, although it does not have to be power of 2).
3629 CONFIG_MTD_UBI_BEB_LIMIT
3630 This option specifies the maximum bad physical eraseblocks UBI
3631 expects on the MTD device (per 1024 eraseblocks). If the
3632 underlying flash does not admit of bad eraseblocks (e.g. NOR
3633 flash), this value is ignored.
3635 NAND datasheets often specify the minimum and maximum NVM
3636 (Number of Valid Blocks) for the flashes' endurance lifetime.
3637 The maximum expected bad eraseblocks per 1024 eraseblocks
3638 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3639 which gives 20 for most NANDs (MaxNVB is basically the total
3640 count of eraseblocks on the chip).
3642 To put it differently, if this value is 20, UBI will try to
3643 reserve about 1.9% of physical eraseblocks for bad blocks
3644 handling. And that will be 1.9% of eraseblocks on the entire
3645 NAND chip, not just the MTD partition UBI attaches. This means
3646 that if you have, say, a NAND flash chip admits maximum 40 bad
3647 eraseblocks, and it is split on two MTD partitions of the same
3648 size, UBI will reserve 40 eraseblocks when attaching a
3653 CONFIG_MTD_UBI_FASTMAP
3654 Fastmap is a mechanism which allows attaching an UBI device
3655 in nearly constant time. Instead of scanning the whole MTD device it
3656 only has to locate a checkpoint (called fastmap) on the device.
3657 The on-flash fastmap contains all information needed to attach
3658 the device. Using fastmap makes only sense on large devices where
3659 attaching by scanning takes long. UBI will not automatically install
3660 a fastmap on old images, but you can set the UBI parameter
3661 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3662 that fastmap-enabled images are still usable with UBI implementations
3663 without fastmap support. On typical flash devices the whole fastmap
3664 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3666 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3667 Set this parameter to enable fastmap automatically on images
3674 Adds commands for interacting with UBI volumes formatted as
3675 UBIFS. UBIFS is read-only in u-boot.
3677 Requires UBI support as well as CONFIG_LZO
3679 CONFIG_UBIFS_SILENCE_MSG
3681 Make the verbose messages from UBIFS stop printing. This leaves
3682 warnings and errors enabled.
3686 Enable building of SPL globally.
3689 LDSCRIPT for linking the SPL binary.
3691 CONFIG_SPL_MAX_FOOTPRINT
3692 Maximum size in memory allocated to the SPL, BSS included.
3693 When defined, the linker checks that the actual memory
3694 used by SPL from _start to __bss_end does not exceed it.
3695 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3696 must not be both defined at the same time.
3699 Maximum size of the SPL image (text, data, rodata, and
3700 linker lists sections), BSS excluded.
3701 When defined, the linker checks that the actual size does
3704 CONFIG_SPL_TEXT_BASE
3705 TEXT_BASE for linking the SPL binary.
3707 CONFIG_SPL_RELOC_TEXT_BASE
3708 Address to relocate to. If unspecified, this is equal to
3709 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3711 CONFIG_SPL_BSS_START_ADDR
3712 Link address for the BSS within the SPL binary.
3714 CONFIG_SPL_BSS_MAX_SIZE
3715 Maximum size in memory allocated to the SPL BSS.
3716 When defined, the linker checks that the actual memory used
3717 by SPL from __bss_start to __bss_end does not exceed it.
3718 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3719 must not be both defined at the same time.
3722 Adress of the start of the stack SPL will use
3724 CONFIG_SPL_RELOC_STACK
3725 Adress of the start of the stack SPL will use after
3726 relocation. If unspecified, this is equal to
3729 CONFIG_SYS_SPL_MALLOC_START
3730 Starting address of the malloc pool used in SPL.
3732 CONFIG_SYS_SPL_MALLOC_SIZE
3733 The size of the malloc pool used in SPL.
3735 CONFIG_SPL_FRAMEWORK
3736 Enable the SPL framework under common/. This framework
3737 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3738 NAND loading of the Linux Kernel.
3741 Enable booting directly to an OS from SPL.
3742 See also: doc/README.falcon
3744 CONFIG_SPL_DISPLAY_PRINT
3745 For ARM, enable an optional function to print more information
3746 about the running system.
3748 CONFIG_SPL_INIT_MINIMAL
3749 Arch init code should be built for a very small image
3751 CONFIG_SPL_LIBCOMMON_SUPPORT
3752 Support for common/libcommon.o in SPL binary
3754 CONFIG_SPL_LIBDISK_SUPPORT
3755 Support for disk/libdisk.o in SPL binary
3757 CONFIG_SPL_I2C_SUPPORT
3758 Support for drivers/i2c/libi2c.o in SPL binary
3760 CONFIG_SPL_GPIO_SUPPORT
3761 Support for drivers/gpio/libgpio.o in SPL binary
3763 CONFIG_SPL_MMC_SUPPORT
3764 Support for drivers/mmc/libmmc.o in SPL binary
3766 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3767 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3768 Address and partition on the MMC to load U-Boot from
3769 when the MMC is being used in raw mode.
3771 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3772 Partition on the MMC to load U-Boot from when the MMC is being
3775 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3776 Sector to load kernel uImage from when MMC is being
3777 used in raw mode (for Falcon mode)
3779 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3780 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3781 Sector and number of sectors to load kernel argument
3782 parameters from when MMC is being used in raw mode
3785 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3786 Partition on the MMC to load U-Boot from when the MMC is being
3789 CONFIG_SPL_FAT_SUPPORT
3790 Support for fs/fat/libfat.o in SPL binary
3792 CONFIG_SPL_EXT_SUPPORT
3793 Support for EXT filesystem in SPL binary
3795 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3796 Filename to read to load U-Boot when reading from filesystem
3798 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3799 Filename to read to load kernel uImage when reading
3800 from filesystem (for Falcon mode)
3802 CONFIG_SPL_FS_LOAD_ARGS_NAME
3803 Filename to read to load kernel argument parameters
3804 when reading from filesystem (for Falcon mode)
3806 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3807 Set this for NAND SPL on PPC mpc83xx targets, so that
3808 start.S waits for the rest of the SPL to load before
3809 continuing (the hardware starts execution after just
3810 loading the first page rather than the full 4K).
3812 CONFIG_SPL_SKIP_RELOCATE
3813 Avoid SPL relocation
3815 CONFIG_SPL_NAND_BASE
3816 Include nand_base.c in the SPL. Requires
3817 CONFIG_SPL_NAND_DRIVERS.
3819 CONFIG_SPL_NAND_DRIVERS
3820 SPL uses normal NAND drivers, not minimal drivers.
3823 Include standard software ECC in the SPL
3825 CONFIG_SPL_NAND_SIMPLE
3826 Support for NAND boot using simple NAND drivers that
3827 expose the cmd_ctrl() interface.
3829 CONFIG_SPL_MTD_SUPPORT
3830 Support for the MTD subsystem within SPL. Useful for
3831 environment on NAND support within SPL.
3833 CONFIG_SPL_NAND_RAW_ONLY
3834 Support to boot only raw u-boot.bin images. Use this only
3835 if you need to save space.
3837 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3838 Set for the SPL on PPC mpc8xxx targets, support for
3839 drivers/ddr/fsl/libddr.o in SPL binary.
3841 CONFIG_SPL_COMMON_INIT_DDR
3842 Set for common ddr init with serial presence detect in
3845 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3846 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3847 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3848 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3849 CONFIG_SYS_NAND_ECCBYTES
3850 Defines the size and behavior of the NAND that SPL uses
3853 CONFIG_SPL_NAND_BOOT
3854 Add support NAND boot
3856 CONFIG_SYS_NAND_U_BOOT_OFFS
3857 Location in NAND to read U-Boot from
3859 CONFIG_SYS_NAND_U_BOOT_DST
3860 Location in memory to load U-Boot to
3862 CONFIG_SYS_NAND_U_BOOT_SIZE
3863 Size of image to load
3865 CONFIG_SYS_NAND_U_BOOT_START
3866 Entry point in loaded image to jump to
3868 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3869 Define this if you need to first read the OOB and then the
3870 data. This is used, for example, on davinci platforms.
3872 CONFIG_SPL_OMAP3_ID_NAND
3873 Support for an OMAP3-specific set of functions to return the
3874 ID and MFR of the first attached NAND chip, if present.
3876 CONFIG_SPL_SERIAL_SUPPORT
3877 Support for drivers/serial/libserial.o in SPL binary
3879 CONFIG_SPL_SPI_FLASH_SUPPORT
3880 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3882 CONFIG_SPL_SPI_SUPPORT
3883 Support for drivers/spi/libspi.o in SPL binary
3885 CONFIG_SPL_RAM_DEVICE
3886 Support for running image already present in ram, in SPL binary
3888 CONFIG_SPL_LIBGENERIC_SUPPORT
3889 Support for lib/libgeneric.o in SPL binary
3891 CONFIG_SPL_ENV_SUPPORT
3892 Support for the environment operating in SPL binary
3894 CONFIG_SPL_NET_SUPPORT
3895 Support for the net/libnet.o in SPL binary.
3896 It conflicts with SPL env from storage medium specified by
3897 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3900 Image offset to which the SPL should be padded before appending
3901 the SPL payload. By default, this is defined as
3902 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3903 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3904 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3907 Final target image containing SPL and payload. Some SPLs
3908 use an arch-specific makefile fragment instead, for
3909 example if more than one image needs to be produced.
3911 CONFIG_FIT_SPL_PRINT
3912 Printing information about a FIT image adds quite a bit of
3913 code to SPL. So this is normally disabled in SPL. Use this
3914 option to re-enable it. This will affect the output of the
3915 bootm command when booting a FIT image.
3919 Enable building of TPL globally.
3922 Image offset to which the TPL should be padded before appending
3923 the TPL payload. By default, this is defined as
3924 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3925 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3926 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3931 [so far only for SMDK2400 boards]
3933 - Modem support enable:
3934 CONFIG_MODEM_SUPPORT
3936 - RTS/CTS Flow control enable:
3939 - Modem debug support:
3940 CONFIG_MODEM_SUPPORT_DEBUG
3942 Enables debugging stuff (char screen[1024], dbg())
3943 for modem support. Useful only with BDI2000.
3945 - Interrupt support (PPC):
3947 There are common interrupt_init() and timer_interrupt()
3948 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3949 for CPU specific initialization. interrupt_init_cpu()
3950 should set decrementer_count to appropriate value. If
3951 CPU resets decrementer automatically after interrupt
3952 (ppc4xx) it should set decrementer_count to zero.
3953 timer_interrupt() calls timer_interrupt_cpu() for CPU
3954 specific handling. If board has watchdog / status_led
3955 / other_activity_monitor it works automatically from
3956 general timer_interrupt().
3960 In the target system modem support is enabled when a
3961 specific key (key combination) is pressed during
3962 power-on. Otherwise U-Boot will boot normally
3963 (autoboot). The key_pressed() function is called from
3964 board_init(). Currently key_pressed() is a dummy
3965 function, returning 1 and thus enabling modem
3968 If there are no modem init strings in the
3969 environment, U-Boot proceed to autoboot; the
3970 previous output (banner, info printfs) will be
3973 See also: doc/README.Modem
3975 Board initialization settings:
3976 ------------------------------
3978 During Initialization u-boot calls a number of board specific functions
3979 to allow the preparation of board specific prerequisites, e.g. pin setup
3980 before drivers are initialized. To enable these callbacks the
3981 following configuration macros have to be defined. Currently this is
3982 architecture specific, so please check arch/your_architecture/lib/board.c
3983 typically in board_init_f() and board_init_r().
3985 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3986 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3987 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3988 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3990 Configuration Settings:
3991 -----------------------
3993 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3994 Optionally it can be defined to support 64-bit memory commands.
3996 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3997 undefine this when you're short of memory.
3999 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
4000 width of the commands listed in the 'help' command output.
4002 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
4003 prompt for user input.
4005 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
4007 - CONFIG_SYS_PBSIZE: Buffer size for Console output
4009 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
4011 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
4012 the application (usually a Linux kernel) when it is
4015 - CONFIG_SYS_BAUDRATE_TABLE:
4016 List of legal baudrate settings for this board.
4018 - CONFIG_SYS_CONSOLE_INFO_QUIET
4019 Suppress display of console information at boot.
4021 - CONFIG_SYS_CONSOLE_IS_IN_ENV
4022 If the board specific function
4023 extern int overwrite_console (void);
4024 returns 1, the stdin, stderr and stdout are switched to the
4025 serial port, else the settings in the environment are used.
4027 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
4028 Enable the call to overwrite_console().
4030 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
4031 Enable overwrite of previous console environment settings.
4033 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
4034 Begin and End addresses of the area used by the
4037 - CONFIG_SYS_ALT_MEMTEST:
4038 Enable an alternate, more extensive memory test.
4040 - CONFIG_SYS_MEMTEST_SCRATCH:
4041 Scratch address used by the alternate memory test
4042 You only need to set this if address zero isn't writeable
4044 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
4045 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
4046 this specified memory area will get subtracted from the top
4047 (end) of RAM and won't get "touched" at all by U-Boot. By
4048 fixing up gd->ram_size the Linux kernel should gets passed
4049 the now "corrected" memory size and won't touch it either.
4050 This should work for arch/ppc and arch/powerpc. Only Linux
4051 board ports in arch/powerpc with bootwrapper support that
4052 recalculate the memory size from the SDRAM controller setup
4053 will have to get fixed in Linux additionally.
4055 This option can be used as a workaround for the 440EPx/GRx
4056 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
4059 WARNING: Please make sure that this value is a multiple of
4060 the Linux page size (normally 4k). If this is not the case,
4061 then the end address of the Linux memory will be located at a
4062 non page size aligned address and this could cause major
4065 - CONFIG_SYS_LOADS_BAUD_CHANGE:
4066 Enable temporary baudrate change while serial download
4068 - CONFIG_SYS_SDRAM_BASE:
4069 Physical start address of SDRAM. _Must_ be 0 here.
4071 - CONFIG_SYS_MBIO_BASE:
4072 Physical start address of Motherboard I/O (if using a
4075 - CONFIG_SYS_FLASH_BASE:
4076 Physical start address of Flash memory.
4078 - CONFIG_SYS_MONITOR_BASE:
4079 Physical start address of boot monitor code (set by
4080 make config files to be same as the text base address
4081 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
4082 CONFIG_SYS_FLASH_BASE when booting from flash.
4084 - CONFIG_SYS_MONITOR_LEN:
4085 Size of memory reserved for monitor code, used to
4086 determine _at_compile_time_ (!) if the environment is
4087 embedded within the U-Boot image, or in a separate
4090 - CONFIG_SYS_MALLOC_LEN:
4091 Size of DRAM reserved for malloc() use.
4093 - CONFIG_SYS_MALLOC_F_LEN
4094 Size of the malloc() pool for use before relocation. If
4095 this is defined, then a very simple malloc() implementation
4096 will become available before relocation. The address is just
4097 below the global data, and the stack is moved down to make
4100 This feature allocates regions with increasing addresses
4101 within the region. calloc() is supported, but realloc()
4102 is not available. free() is supported but does nothing.
4103 The memory will be freed (or in fact just forgotten) when
4104 U-Boot relocates itself.
4106 Pre-relocation malloc() is only supported on ARM and sandbox
4107 at present but is fairly easy to enable for other archs.
4109 - CONFIG_SYS_MALLOC_SIMPLE
4110 Provides a simple and small malloc() and calloc() for those
4111 boards which do not use the full malloc in SPL (which is
4112 enabled with CONFIG_SYS_SPL_MALLOC_START).
4114 - CONFIG_SYS_NONCACHED_MEMORY:
4115 Size of non-cached memory area. This area of memory will be
4116 typically located right below the malloc() area and mapped
4117 uncached in the MMU. This is useful for drivers that would
4118 otherwise require a lot of explicit cache maintenance. For
4119 some drivers it's also impossible to properly maintain the
4120 cache. For example if the regions that need to be flushed
4121 are not a multiple of the cache-line size, *and* padding
4122 cannot be allocated between the regions to align them (i.e.
4123 if the HW requires a contiguous array of regions, and the
4124 size of each region is not cache-aligned), then a flush of
4125 one region may result in overwriting data that hardware has
4126 written to another region in the same cache-line. This can
4127 happen for example in network drivers where descriptors for
4128 buffers are typically smaller than the CPU cache-line (e.g.
4129 16 bytes vs. 32 or 64 bytes).
4131 Non-cached memory is only supported on 32-bit ARM at present.
4133 - CONFIG_SYS_BOOTM_LEN:
4134 Normally compressed uImages are limited to an
4135 uncompressed size of 8 MBytes. If this is not enough,
4136 you can define CONFIG_SYS_BOOTM_LEN in your board config file
4137 to adjust this setting to your needs.
4139 - CONFIG_SYS_BOOTMAPSZ:
4140 Maximum size of memory mapped by the startup code of
4141 the Linux kernel; all data that must be processed by
4142 the Linux kernel (bd_info, boot arguments, FDT blob if
4143 used) must be put below this limit, unless "bootm_low"
4144 environment variable is defined and non-zero. In such case
4145 all data for the Linux kernel must be between "bootm_low"
4146 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
4147 variable "bootm_mapsize" will override the value of
4148 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
4149 then the value in "bootm_size" will be used instead.
4151 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
4152 Enable initrd_high functionality. If defined then the
4153 initrd_high feature is enabled and the bootm ramdisk subcommand
4156 - CONFIG_SYS_BOOT_GET_CMDLINE:
4157 Enables allocating and saving kernel cmdline in space between
4158 "bootm_low" and "bootm_low" + BOOTMAPSZ.
4160 - CONFIG_SYS_BOOT_GET_KBD:
4161 Enables allocating and saving a kernel copy of the bd_info in
4162 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
4164 - CONFIG_SYS_MAX_FLASH_BANKS:
4165 Max number of Flash memory banks
4167 - CONFIG_SYS_MAX_FLASH_SECT:
4168 Max number of sectors on a Flash chip
4170 - CONFIG_SYS_FLASH_ERASE_TOUT:
4171 Timeout for Flash erase operations (in ms)
4173 - CONFIG_SYS_FLASH_WRITE_TOUT:
4174 Timeout for Flash write operations (in ms)
4176 - CONFIG_SYS_FLASH_LOCK_TOUT
4177 Timeout for Flash set sector lock bit operation (in ms)
4179 - CONFIG_SYS_FLASH_UNLOCK_TOUT
4180 Timeout for Flash clear lock bits operation (in ms)
4182 - CONFIG_SYS_FLASH_PROTECTION
4183 If defined, hardware flash sectors protection is used
4184 instead of U-Boot software protection.
4186 - CONFIG_SYS_DIRECT_FLASH_TFTP:
4188 Enable TFTP transfers directly to flash memory;
4189 without this option such a download has to be
4190 performed in two steps: (1) download to RAM, and (2)
4191 copy from RAM to flash.
4193 The two-step approach is usually more reliable, since
4194 you can check if the download worked before you erase
4195 the flash, but in some situations (when system RAM is
4196 too limited to allow for a temporary copy of the
4197 downloaded image) this option may be very useful.
4199 - CONFIG_SYS_FLASH_CFI:
4200 Define if the flash driver uses extra elements in the
4201 common flash structure for storing flash geometry.
4203 - CONFIG_FLASH_CFI_DRIVER
4204 This option also enables the building of the cfi_flash driver
4205 in the drivers directory
4207 - CONFIG_FLASH_CFI_MTD
4208 This option enables the building of the cfi_mtd driver
4209 in the drivers directory. The driver exports CFI flash
4212 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
4213 Use buffered writes to flash.
4215 - CONFIG_FLASH_SPANSION_S29WS_N
4216 s29ws-n MirrorBit flash has non-standard addresses for buffered
4219 - CONFIG_SYS_FLASH_QUIET_TEST
4220 If this option is defined, the common CFI flash doesn't
4221 print it's warning upon not recognized FLASH banks. This
4222 is useful, if some of the configured banks are only
4223 optionally available.
4225 - CONFIG_FLASH_SHOW_PROGRESS
4226 If defined (must be an integer), print out countdown
4227 digits and dots. Recommended value: 45 (9..1) for 80
4228 column displays, 15 (3..1) for 40 column displays.
4230 - CONFIG_FLASH_VERIFY
4231 If defined, the content of the flash (destination) is compared
4232 against the source after the write operation. An error message
4233 will be printed when the contents are not identical.
4234 Please note that this option is useless in nearly all cases,
4235 since such flash programming errors usually are detected earlier
4236 while unprotecting/erasing/programming. Please only enable
4237 this option if you really know what you are doing.
4239 - CONFIG_SYS_RX_ETH_BUFFER:
4240 Defines the number of Ethernet receive buffers. On some
4241 Ethernet controllers it is recommended to set this value
4242 to 8 or even higher (EEPRO100 or 405 EMAC), since all
4243 buffers can be full shortly after enabling the interface
4244 on high Ethernet traffic.
4245 Defaults to 4 if not defined.
4247 - CONFIG_ENV_MAX_ENTRIES
4249 Maximum number of entries in the hash table that is used
4250 internally to store the environment settings. The default
4251 setting is supposed to be generous and should work in most
4252 cases. This setting can be used to tune behaviour; see
4253 lib/hashtable.c for details.
4255 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4256 - CONFIG_ENV_FLAGS_LIST_STATIC
4257 Enable validation of the values given to environment variables when
4258 calling env set. Variables can be restricted to only decimal,
4259 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
4260 the variables can also be restricted to IP address or MAC address.
4262 The format of the list is:
4263 type_attribute = [s|d|x|b|i|m]
4264 access_attribute = [a|r|o|c]
4265 attributes = type_attribute[access_attribute]
4266 entry = variable_name[:attributes]
4269 The type attributes are:
4270 s - String (default)
4273 b - Boolean ([1yYtT|0nNfF])
4277 The access attributes are:
4283 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4284 Define this to a list (string) to define the ".flags"
4285 environment variable in the default or embedded environment.
4287 - CONFIG_ENV_FLAGS_LIST_STATIC
4288 Define this to a list (string) to define validation that
4289 should be done if an entry is not found in the ".flags"
4290 environment variable. To override a setting in the static
4291 list, simply add an entry for the same variable name to the
4294 - CONFIG_ENV_ACCESS_IGNORE_FORCE
4295 If defined, don't allow the -f switch to env set override variable
4298 - CONFIG_SYS_GENERIC_BOARD
4299 This selects the architecture-generic board system instead of the
4300 architecture-specific board files. It is intended to move boards
4301 to this new framework over time. Defining this will disable the
4302 arch/foo/lib/board.c file and use common/board_f.c and
4303 common/board_r.c instead. To use this option your architecture
4304 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
4305 its config.mk file). If you find problems enabling this option on
4306 your board please report the problem and send patches!
4308 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
4309 This is set by OMAP boards for the max time that reset should
4310 be asserted. See doc/README.omap-reset-time for details on how
4311 the value can be calculated on a given board.
4314 If stdint.h is available with your toolchain you can define this
4315 option to enable it. You can provide option 'USE_STDINT=1' when
4316 building U-Boot to enable this.
4318 The following definitions that deal with the placement and management
4319 of environment data (variable area); in general, we support the
4320 following configurations:
4322 - CONFIG_BUILD_ENVCRC:
4324 Builds up envcrc with the target environment so that external utils
4325 may easily extract it and embed it in final U-Boot images.
4327 - CONFIG_ENV_IS_IN_FLASH:
4329 Define this if the environment is in flash memory.
4331 a) The environment occupies one whole flash sector, which is
4332 "embedded" in the text segment with the U-Boot code. This
4333 happens usually with "bottom boot sector" or "top boot
4334 sector" type flash chips, which have several smaller
4335 sectors at the start or the end. For instance, such a
4336 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4337 such a case you would place the environment in one of the
4338 4 kB sectors - with U-Boot code before and after it. With
4339 "top boot sector" type flash chips, you would put the
4340 environment in one of the last sectors, leaving a gap
4341 between U-Boot and the environment.
4343 - CONFIG_ENV_OFFSET:
4345 Offset of environment data (variable area) to the
4346 beginning of flash memory; for instance, with bottom boot
4347 type flash chips the second sector can be used: the offset
4348 for this sector is given here.
4350 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4354 This is just another way to specify the start address of
4355 the flash sector containing the environment (instead of
4358 - CONFIG_ENV_SECT_SIZE:
4360 Size of the sector containing the environment.
4363 b) Sometimes flash chips have few, equal sized, BIG sectors.
4364 In such a case you don't want to spend a whole sector for
4369 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4370 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4371 of this flash sector for the environment. This saves
4372 memory for the RAM copy of the environment.
4374 It may also save flash memory if you decide to use this
4375 when your environment is "embedded" within U-Boot code,
4376 since then the remainder of the flash sector could be used
4377 for U-Boot code. It should be pointed out that this is
4378 STRONGLY DISCOURAGED from a robustness point of view:
4379 updating the environment in flash makes it always
4380 necessary to erase the WHOLE sector. If something goes
4381 wrong before the contents has been restored from a copy in
4382 RAM, your target system will be dead.
4384 - CONFIG_ENV_ADDR_REDUND
4385 CONFIG_ENV_SIZE_REDUND
4387 These settings describe a second storage area used to hold
4388 a redundant copy of the environment data, so that there is
4389 a valid backup copy in case there is a power failure during
4390 a "saveenv" operation.
4392 BE CAREFUL! Any changes to the flash layout, and some changes to the
4393 source code will make it necessary to adapt <board>/u-boot.lds*
4397 - CONFIG_ENV_IS_IN_NVRAM:
4399 Define this if you have some non-volatile memory device
4400 (NVRAM, battery buffered SRAM) which you want to use for the
4406 These two #defines are used to determine the memory area you
4407 want to use for environment. It is assumed that this memory
4408 can just be read and written to, without any special
4411 BE CAREFUL! The first access to the environment happens quite early
4412 in U-Boot initialization (when we try to get the setting of for the
4413 console baudrate). You *MUST* have mapped your NVRAM area then, or
4416 Please note that even with NVRAM we still use a copy of the
4417 environment in RAM: we could work on NVRAM directly, but we want to
4418 keep settings there always unmodified except somebody uses "saveenv"
4419 to save the current settings.
4422 - CONFIG_ENV_IS_IN_EEPROM:
4424 Use this if you have an EEPROM or similar serial access
4425 device and a driver for it.
4427 - CONFIG_ENV_OFFSET:
4430 These two #defines specify the offset and size of the
4431 environment area within the total memory of your EEPROM.
4433 - CONFIG_SYS_I2C_EEPROM_ADDR:
4434 If defined, specified the chip address of the EEPROM device.
4435 The default address is zero.
4437 - CONFIG_SYS_I2C_EEPROM_BUS:
4438 If defined, specified the i2c bus of the EEPROM device.
4440 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4441 If defined, the number of bits used to address bytes in a
4442 single page in the EEPROM device. A 64 byte page, for example
4443 would require six bits.
4445 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4446 If defined, the number of milliseconds to delay between
4447 page writes. The default is zero milliseconds.
4449 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4450 The length in bytes of the EEPROM memory array address. Note
4451 that this is NOT the chip address length!
4453 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4454 EEPROM chips that implement "address overflow" are ones
4455 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4456 address and the extra bits end up in the "chip address" bit
4457 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4460 Note that we consider the length of the address field to
4461 still be one byte because the extra address bits are hidden
4462 in the chip address.
4464 - CONFIG_SYS_EEPROM_SIZE:
4465 The size in bytes of the EEPROM device.
4467 - CONFIG_ENV_EEPROM_IS_ON_I2C
4468 define this, if you have I2C and SPI activated, and your
4469 EEPROM, which holds the environment, is on the I2C bus.
4471 - CONFIG_I2C_ENV_EEPROM_BUS
4472 if you have an Environment on an EEPROM reached over
4473 I2C muxes, you can define here, how to reach this
4474 EEPROM. For example:
4476 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4478 EEPROM which holds the environment, is reached over
4479 a pca9547 i2c mux with address 0x70, channel 3.
4481 - CONFIG_ENV_IS_IN_DATAFLASH:
4483 Define this if you have a DataFlash memory device which you
4484 want to use for the environment.
4486 - CONFIG_ENV_OFFSET:
4490 These three #defines specify the offset and size of the
4491 environment area within the total memory of your DataFlash placed
4492 at the specified address.
4494 - CONFIG_ENV_IS_IN_SPI_FLASH:
4496 Define this if you have a SPI Flash memory device which you
4497 want to use for the environment.
4499 - CONFIG_ENV_OFFSET:
4502 These two #defines specify the offset and size of the
4503 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4504 aligned to an erase sector boundary.
4506 - CONFIG_ENV_SECT_SIZE:
4508 Define the SPI flash's sector size.
4510 - CONFIG_ENV_OFFSET_REDUND (optional):
4512 This setting describes a second storage area of CONFIG_ENV_SIZE
4513 size used to hold a redundant copy of the environment data, so
4514 that there is a valid backup copy in case there is a power failure
4515 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4516 aligned to an erase sector boundary.
4518 - CONFIG_ENV_SPI_BUS (optional):
4519 - CONFIG_ENV_SPI_CS (optional):
4521 Define the SPI bus and chip select. If not defined they will be 0.
4523 - CONFIG_ENV_SPI_MAX_HZ (optional):
4525 Define the SPI max work clock. If not defined then use 1MHz.
4527 - CONFIG_ENV_SPI_MODE (optional):
4529 Define the SPI work mode. If not defined then use SPI_MODE_3.
4531 - CONFIG_ENV_IS_IN_REMOTE:
4533 Define this if you have a remote memory space which you
4534 want to use for the local device's environment.
4539 These two #defines specify the address and size of the
4540 environment area within the remote memory space. The
4541 local device can get the environment from remote memory
4542 space by SRIO or PCIE links.
4544 BE CAREFUL! For some special cases, the local device can not use
4545 "saveenv" command. For example, the local device will get the
4546 environment stored in a remote NOR flash by SRIO or PCIE link,
4547 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4549 - CONFIG_ENV_IS_IN_NAND:
4551 Define this if you have a NAND device which you want to use
4552 for the environment.
4554 - CONFIG_ENV_OFFSET:
4557 These two #defines specify the offset and size of the environment
4558 area within the first NAND device. CONFIG_ENV_OFFSET must be
4559 aligned to an erase block boundary.
4561 - CONFIG_ENV_OFFSET_REDUND (optional):
4563 This setting describes a second storage area of CONFIG_ENV_SIZE
4564 size used to hold a redundant copy of the environment data, so
4565 that there is a valid backup copy in case there is a power failure
4566 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4567 aligned to an erase block boundary.
4569 - CONFIG_ENV_RANGE (optional):
4571 Specifies the length of the region in which the environment
4572 can be written. This should be a multiple of the NAND device's
4573 block size. Specifying a range with more erase blocks than
4574 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4575 the range to be avoided.
4577 - CONFIG_ENV_OFFSET_OOB (optional):
4579 Enables support for dynamically retrieving the offset of the
4580 environment from block zero's out-of-band data. The
4581 "nand env.oob" command can be used to record this offset.
4582 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4583 using CONFIG_ENV_OFFSET_OOB.
4585 - CONFIG_NAND_ENV_DST
4587 Defines address in RAM to which the nand_spl code should copy the
4588 environment. If redundant environment is used, it will be copied to
4589 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4591 - CONFIG_ENV_IS_IN_UBI:
4593 Define this if you have an UBI volume that you want to use for the
4594 environment. This has the benefit of wear-leveling the environment
4595 accesses, which is important on NAND.
4597 - CONFIG_ENV_UBI_PART:
4599 Define this to a string that is the mtd partition containing the UBI.
4601 - CONFIG_ENV_UBI_VOLUME:
4603 Define this to the name of the volume that you want to store the
4606 - CONFIG_ENV_UBI_VOLUME_REDUND:
4608 Define this to the name of another volume to store a second copy of
4609 the environment in. This will enable redundant environments in UBI.
4610 It is assumed that both volumes are in the same MTD partition.
4612 - CONFIG_UBI_SILENCE_MSG
4613 - CONFIG_UBIFS_SILENCE_MSG
4615 You will probably want to define these to avoid a really noisy system
4616 when storing the env in UBI.
4618 - CONFIG_ENV_IS_IN_FAT:
4619 Define this if you want to use the FAT file system for the environment.
4621 - FAT_ENV_INTERFACE:
4623 Define this to a string that is the name of the block device.
4625 - FAT_ENV_DEV_AND_PART:
4627 Define this to a string to specify the partition of the device. It can
4630 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4631 - "D:P": device D partition P. Error occurs if device D has no
4634 - "D" or "D:": device D partition 1 if device D has partition
4635 table, or the whole device D if has no partition
4637 - "D:auto": first partition in device D with bootable flag set.
4638 If none, first valid partition in device D. If no
4639 partition table then means device D.
4643 It's a string of the FAT file name. This file use to store the
4647 This should be defined. Otherwise it cannot save the environment file.
4649 - CONFIG_ENV_IS_IN_MMC:
4651 Define this if you have an MMC device which you want to use for the
4654 - CONFIG_SYS_MMC_ENV_DEV:
4656 Specifies which MMC device the environment is stored in.
4658 - CONFIG_SYS_MMC_ENV_PART (optional):
4660 Specifies which MMC partition the environment is stored in. If not
4661 set, defaults to partition 0, the user area. Common values might be
4662 1 (first MMC boot partition), 2 (second MMC boot partition).
4664 - CONFIG_ENV_OFFSET:
4667 These two #defines specify the offset and size of the environment
4668 area within the specified MMC device.
4670 If offset is positive (the usual case), it is treated as relative to
4671 the start of the MMC partition. If offset is negative, it is treated
4672 as relative to the end of the MMC partition. This can be useful if
4673 your board may be fitted with different MMC devices, which have
4674 different sizes for the MMC partitions, and you always want the
4675 environment placed at the very end of the partition, to leave the
4676 maximum possible space before it, to store other data.
4678 These two values are in units of bytes, but must be aligned to an
4679 MMC sector boundary.
4681 - CONFIG_ENV_OFFSET_REDUND (optional):
4683 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4684 hold a redundant copy of the environment data. This provides a
4685 valid backup copy in case the other copy is corrupted, e.g. due
4686 to a power failure during a "saveenv" operation.
4688 This value may also be positive or negative; this is handled in the
4689 same way as CONFIG_ENV_OFFSET.
4691 This value is also in units of bytes, but must also be aligned to
4692 an MMC sector boundary.
4694 - CONFIG_ENV_SIZE_REDUND (optional):
4696 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4697 set. If this value is set, it must be set to the same value as
4700 - CONFIG_SYS_SPI_INIT_OFFSET
4702 Defines offset to the initial SPI buffer area in DPRAM. The
4703 area is used at an early stage (ROM part) if the environment
4704 is configured to reside in the SPI EEPROM: We need a 520 byte
4705 scratch DPRAM area. It is used between the two initialization
4706 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4707 to be a good choice since it makes it far enough from the
4708 start of the data area as well as from the stack pointer.
4710 Please note that the environment is read-only until the monitor
4711 has been relocated to RAM and a RAM copy of the environment has been
4712 created; also, when using EEPROM you will have to use getenv_f()
4713 until then to read environment variables.
4715 The environment is protected by a CRC32 checksum. Before the monitor
4716 is relocated into RAM, as a result of a bad CRC you will be working
4717 with the compiled-in default environment - *silently*!!! [This is
4718 necessary, because the first environment variable we need is the
4719 "baudrate" setting for the console - if we have a bad CRC, we don't
4720 have any device yet where we could complain.]
4722 Note: once the monitor has been relocated, then it will complain if
4723 the default environment is used; a new CRC is computed as soon as you
4724 use the "saveenv" command to store a valid environment.
4726 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4727 Echo the inverted Ethernet link state to the fault LED.
4729 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4730 also needs to be defined.
4732 - CONFIG_SYS_FAULT_MII_ADDR:
4733 MII address of the PHY to check for the Ethernet link state.
4735 - CONFIG_NS16550_MIN_FUNCTIONS:
4736 Define this if you desire to only have use of the NS16550_init
4737 and NS16550_putc functions for the serial driver located at
4738 drivers/serial/ns16550.c. This option is useful for saving
4739 space for already greatly restricted images, including but not
4740 limited to NAND_SPL configurations.
4742 - CONFIG_DISPLAY_BOARDINFO
4743 Display information about the board that U-Boot is running on
4744 when U-Boot starts up. The board function checkboard() is called
4747 - CONFIG_DISPLAY_BOARDINFO_LATE
4748 Similar to the previous option, but display this information
4749 later, once stdio is running and output goes to the LCD, if
4752 - CONFIG_BOARD_SIZE_LIMIT:
4753 Maximum size of the U-Boot image. When defined, the
4754 build system checks that the actual size does not
4757 Low Level (hardware related) configuration options:
4758 ---------------------------------------------------
4760 - CONFIG_SYS_CACHELINE_SIZE:
4761 Cache Line Size of the CPU.
4763 - CONFIG_SYS_DEFAULT_IMMR:
4764 Default address of the IMMR after system reset.
4766 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4767 and RPXsuper) to be able to adjust the position of
4768 the IMMR register after a reset.
4770 - CONFIG_SYS_CCSRBAR_DEFAULT:
4771 Default (power-on reset) physical address of CCSR on Freescale
4774 - CONFIG_SYS_CCSRBAR:
4775 Virtual address of CCSR. On a 32-bit build, this is typically
4776 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4778 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4779 for cross-platform code that uses that macro instead.
4781 - CONFIG_SYS_CCSRBAR_PHYS:
4782 Physical address of CCSR. CCSR can be relocated to a new
4783 physical address, if desired. In this case, this macro should
4784 be set to that address. Otherwise, it should be set to the
4785 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4786 is typically relocated on 36-bit builds. It is recommended
4787 that this macro be defined via the _HIGH and _LOW macros:
4789 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4790 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4792 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4793 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4794 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4795 used in assembly code, so it must not contain typecasts or
4796 integer size suffixes (e.g. "ULL").
4798 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4799 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4800 used in assembly code, so it must not contain typecasts or
4801 integer size suffixes (e.g. "ULL").
4803 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4804 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4805 forced to a value that ensures that CCSR is not relocated.
4807 - Floppy Disk Support:
4808 CONFIG_SYS_FDC_DRIVE_NUMBER
4810 the default drive number (default value 0)
4812 CONFIG_SYS_ISA_IO_STRIDE
4814 defines the spacing between FDC chipset registers
4817 CONFIG_SYS_ISA_IO_OFFSET
4819 defines the offset of register from address. It
4820 depends on which part of the data bus is connected to
4821 the FDC chipset. (default value 0)
4823 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4824 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4827 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4828 fdc_hw_init() is called at the beginning of the FDC
4829 setup. fdc_hw_init() must be provided by the board
4830 source code. It is used to make hardware-dependent
4834 Most IDE controllers were designed to be connected with PCI
4835 interface. Only few of them were designed for AHB interface.
4836 When software is doing ATA command and data transfer to
4837 IDE devices through IDE-AHB controller, some additional
4838 registers accessing to these kind of IDE-AHB controller
4841 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4842 DO NOT CHANGE unless you know exactly what you're
4843 doing! (11-4) [MPC8xx/82xx systems only]
4845 - CONFIG_SYS_INIT_RAM_ADDR:
4847 Start address of memory area that can be used for
4848 initial data and stack; please note that this must be
4849 writable memory that is working WITHOUT special
4850 initialization, i. e. you CANNOT use normal RAM which
4851 will become available only after programming the
4852 memory controller and running certain initialization
4855 U-Boot uses the following memory types:
4856 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4857 - MPC824X: data cache
4858 - PPC4xx: data cache
4860 - CONFIG_SYS_GBL_DATA_OFFSET:
4862 Offset of the initial data structure in the memory
4863 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4864 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4865 data is located at the end of the available space
4866 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4867 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4868 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4869 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4872 On the MPC824X (or other systems that use the data
4873 cache for initial memory) the address chosen for
4874 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4875 point to an otherwise UNUSED address space between
4876 the top of RAM and the start of the PCI space.
4878 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4880 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4882 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4884 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4886 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4888 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4890 - CONFIG_SYS_OR_TIMING_SDRAM:
4893 - CONFIG_SYS_MAMR_PTA:
4894 periodic timer for refresh
4896 - CONFIG_SYS_DER: Debug Event Register (37-47)
4898 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4899 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4900 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4901 CONFIG_SYS_BR1_PRELIM:
4902 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4904 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4905 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4906 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4907 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4909 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4910 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4911 Machine Mode Register and Memory Periodic Timer
4912 Prescaler definitions (SDRAM timing)
4914 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4915 enable I2C microcode relocation patch (MPC8xx);
4916 define relocation offset in DPRAM [DSP2]
4918 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4919 enable SMC microcode relocation patch (MPC8xx);
4920 define relocation offset in DPRAM [SMC1]
4922 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4923 enable SPI microcode relocation patch (MPC8xx);
4924 define relocation offset in DPRAM [SCC4]
4926 - CONFIG_SYS_USE_OSCCLK:
4927 Use OSCM clock mode on MBX8xx board. Be careful,
4928 wrong setting might damage your board. Read
4929 doc/README.MBX before setting this variable!
4931 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4932 Offset of the bootmode word in DPRAM used by post
4933 (Power On Self Tests). This definition overrides
4934 #define'd default value in commproc.h resp.
4937 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4938 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4939 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4940 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4941 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4942 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4943 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4944 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4945 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4947 - CONFIG_PCI_DISABLE_PCIE:
4948 Disable PCI-Express on systems where it is supported but not
4951 - CONFIG_PCI_ENUM_ONLY
4952 Only scan through and get the devices on the buses.
4953 Don't do any setup work, presumably because someone or
4954 something has already done it, and we don't need to do it
4955 a second time. Useful for platforms that are pre-booted
4956 by coreboot or similar.
4958 - CONFIG_PCI_INDIRECT_BRIDGE:
4959 Enable support for indirect PCI bridges.
4962 Chip has SRIO or not
4965 Board has SRIO 1 port available
4968 Board has SRIO 2 port available
4970 - CONFIG_SRIO_PCIE_BOOT_MASTER
4971 Board can support master function for Boot from SRIO and PCIE
4973 - CONFIG_SYS_SRIOn_MEM_VIRT:
4974 Virtual Address of SRIO port 'n' memory region
4976 - CONFIG_SYS_SRIOn_MEM_PHYS:
4977 Physical Address of SRIO port 'n' memory region
4979 - CONFIG_SYS_SRIOn_MEM_SIZE:
4980 Size of SRIO port 'n' memory region
4982 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4983 Defined to tell the NAND controller that the NAND chip is using
4985 Not all NAND drivers use this symbol.
4986 Example of drivers that use it:
4987 - drivers/mtd/nand/ndfc.c
4988 - drivers/mtd/nand/mxc_nand.c
4990 - CONFIG_SYS_NDFC_EBC0_CFG
4991 Sets the EBC0_CFG register for the NDFC. If not defined
4992 a default value will be used.
4995 Get DDR timing information from an I2C EEPROM. Common
4996 with pluggable memory modules such as SODIMMs
4999 I2C address of the SPD EEPROM
5001 - CONFIG_SYS_SPD_BUS_NUM
5002 If SPD EEPROM is on an I2C bus other than the first
5003 one, specify here. Note that the value must resolve
5004 to something your driver can deal with.
5006 - CONFIG_SYS_DDR_RAW_TIMING
5007 Get DDR timing information from other than SPD. Common with
5008 soldered DDR chips onboard without SPD. DDR raw timing
5009 parameters are extracted from datasheet and hard-coded into
5010 header files or board specific files.
5012 - CONFIG_FSL_DDR_INTERACTIVE
5013 Enable interactive DDR debugging. See doc/README.fsl-ddr.
5015 - CONFIG_FSL_DDR_SYNC_REFRESH
5016 Enable sync of refresh for multiple controllers.
5018 - CONFIG_SYS_83XX_DDR_USES_CS0
5019 Only for 83xx systems. If specified, then DDR should
5020 be configured using CS0 and CS1 instead of CS2 and CS3.
5022 - CONFIG_ETHER_ON_FEC[12]
5023 Define to enable FEC[12] on a 8xx series processor.
5025 - CONFIG_FEC[12]_PHY
5026 Define to the hardcoded PHY address which corresponds
5027 to the given FEC; i. e.
5028 #define CONFIG_FEC1_PHY 4
5029 means that the PHY with address 4 is connected to FEC1
5031 When set to -1, means to probe for first available.
5033 - CONFIG_FEC[12]_PHY_NORXERR
5034 The PHY does not have a RXERR line (RMII only).
5035 (so program the FEC to ignore it).
5038 Enable RMII mode for all FECs.
5039 Note that this is a global option, we can't
5040 have one FEC in standard MII mode and another in RMII mode.
5042 - CONFIG_CRC32_VERIFY
5043 Add a verify option to the crc32 command.
5046 => crc32 -v <address> <count> <crc32>
5048 Where address/count indicate a memory area
5049 and crc32 is the correct crc32 which the
5053 Add the "loopw" memory command. This only takes effect if
5054 the memory commands are activated globally (CONFIG_CMD_MEM).
5057 Add the "mdc" and "mwc" memory commands. These are cyclic
5062 This command will print 4 bytes (10,11,12,13) each 500 ms.
5064 => mwc.l 100 12345678 10
5065 This command will write 12345678 to address 100 all 10 ms.
5067 This only takes effect if the memory commands are activated
5068 globally (CONFIG_CMD_MEM).
5070 - CONFIG_SKIP_LOWLEVEL_INIT
5071 [ARM, NDS32, MIPS only] If this variable is defined, then certain
5072 low level initializations (like setting up the memory
5073 controller) are omitted and/or U-Boot does not
5074 relocate itself into RAM.
5076 Normally this variable MUST NOT be defined. The only
5077 exception is when U-Boot is loaded (to RAM) by some
5078 other boot loader or by a debugger which performs
5079 these initializations itself.
5082 Modifies the behaviour of start.S when compiling a loader
5083 that is executed before the actual U-Boot. E.g. when
5084 compiling a NAND SPL.
5087 Modifies the behaviour of start.S when compiling a loader
5088 that is executed after the SPL and before the actual U-Boot.
5089 It is loaded by the SPL.
5091 - CONFIG_SYS_MPC85XX_NO_RESETVEC
5092 Only for 85xx systems. If this variable is specified, the section
5093 .resetvec is not kept and the section .bootpg is placed in the
5094 previous 4k of the .text section.
5096 - CONFIG_ARCH_MAP_SYSMEM
5097 Generally U-Boot (and in particular the md command) uses
5098 effective address. It is therefore not necessary to regard
5099 U-Boot address as virtual addresses that need to be translated
5100 to physical addresses. However, sandbox requires this, since
5101 it maintains its own little RAM buffer which contains all
5102 addressable memory. This option causes some memory accesses
5103 to be mapped through map_sysmem() / unmap_sysmem().
5105 - CONFIG_USE_ARCH_MEMCPY
5106 CONFIG_USE_ARCH_MEMSET
5107 If these options are used a optimized version of memcpy/memset will
5108 be used if available. These functions may be faster under some
5109 conditions but may increase the binary size.
5111 - CONFIG_X86_RESET_VECTOR
5112 If defined, the x86 reset vector code is included. This is not
5113 needed when U-Boot is running from Coreboot.
5116 Defines the MPU clock speed (in MHz).
5118 NOTE : currently only supported on AM335x platforms.
5120 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
5121 Enables the RTC32K OSC on AM33xx based plattforms
5123 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
5124 Option to disable subpage write in NAND driver
5125 driver that uses this:
5126 drivers/mtd/nand/davinci_nand.c
5128 Freescale QE/FMAN Firmware Support:
5129 -----------------------------------
5131 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
5132 loading of "firmware", which is encoded in the QE firmware binary format.
5133 This firmware often needs to be loaded during U-Boot booting, so macros
5134 are used to identify the storage device (NOR flash, SPI, etc) and the address
5137 - CONFIG_SYS_FMAN_FW_ADDR
5138 The address in the storage device where the FMAN microcode is located. The
5139 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5142 - CONFIG_SYS_QE_FW_ADDR
5143 The address in the storage device where the QE microcode is located. The
5144 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5147 - CONFIG_SYS_QE_FMAN_FW_LENGTH
5148 The maximum possible size of the firmware. The firmware binary format
5149 has a field that specifies the actual size of the firmware, but it
5150 might not be possible to read any part of the firmware unless some
5151 local storage is allocated to hold the entire firmware first.
5153 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
5154 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
5155 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
5156 virtual address in NOR flash.
5158 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
5159 Specifies that QE/FMAN firmware is located in NAND flash.
5160 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
5162 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
5163 Specifies that QE/FMAN firmware is located on the primary SD/MMC
5164 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5166 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
5167 Specifies that QE/FMAN firmware is located on the primary SPI
5168 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5170 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
5171 Specifies that QE/FMAN firmware is located in the remote (master)
5172 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
5173 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
5174 window->master inbound window->master LAW->the ucode address in
5175 master's memory space.
5177 Freescale Layerscape Management Complex Firmware Support:
5178 ---------------------------------------------------------
5179 The Freescale Layerscape Management Complex (MC) supports the loading of
5181 This firmware often needs to be loaded during U-Boot booting, so macros
5182 are used to identify the storage device (NOR flash, SPI, etc) and the address
5185 - CONFIG_FSL_MC_ENET
5186 Enable the MC driver for Layerscape SoCs.
5188 - CONFIG_SYS_LS_MC_FW_ADDR
5189 The address in the storage device where the firmware is located. The
5190 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
5193 - CONFIG_SYS_LS_MC_FW_LENGTH
5194 The maximum possible size of the firmware. The firmware binary format
5195 has a field that specifies the actual size of the firmware, but it
5196 might not be possible to read any part of the firmware unless some
5197 local storage is allocated to hold the entire firmware first.
5199 - CONFIG_SYS_LS_MC_FW_IN_NOR
5200 Specifies that MC firmware is located in NOR flash, mapped as
5201 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
5202 virtual address in NOR flash.
5204 Building the Software:
5205 ======================
5207 Building U-Boot has been tested in several native build environments
5208 and in many different cross environments. Of course we cannot support
5209 all possibly existing versions of cross development tools in all
5210 (potentially obsolete) versions. In case of tool chain problems we
5211 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
5212 which is extensively used to build and test U-Boot.
5214 If you are not using a native environment, it is assumed that you
5215 have GNU cross compiling tools available in your path. In this case,
5216 you must set the environment variable CROSS_COMPILE in your shell.
5217 Note that no changes to the Makefile or any other source files are
5218 necessary. For example using the ELDK on a 4xx CPU, please enter:
5220 $ CROSS_COMPILE=ppc_4xx-
5221 $ export CROSS_COMPILE
5223 Note: If you wish to generate Windows versions of the utilities in
5224 the tools directory you can use the MinGW toolchain
5225 (http://www.mingw.org). Set your HOST tools to the MinGW
5226 toolchain and execute 'make tools'. For example:
5228 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
5230 Binaries such as tools/mkimage.exe will be created which can
5231 be executed on computers running Windows.
5233 U-Boot is intended to be simple to build. After installing the
5234 sources you must configure U-Boot for one specific board type. This
5239 where "NAME_defconfig" is the name of one of the existing configu-
5240 rations; see boards.cfg for supported names.
5242 Note: for some board special configuration names may exist; check if
5243 additional information is available from the board vendor; for
5244 instance, the TQM823L systems are available without (standard)
5245 or with LCD support. You can select such additional "features"
5246 when choosing the configuration, i. e.
5248 make TQM823L_defconfig
5249 - will configure for a plain TQM823L, i. e. no LCD support
5251 make TQM823L_LCD_defconfig
5252 - will configure for a TQM823L with U-Boot console on LCD
5257 Finally, type "make all", and you should get some working U-Boot
5258 images ready for download to / installation on your system:
5260 - "u-boot.bin" is a raw binary image
5261 - "u-boot" is an image in ELF binary format
5262 - "u-boot.srec" is in Motorola S-Record format
5264 By default the build is performed locally and the objects are saved
5265 in the source directory. One of the two methods can be used to change
5266 this behavior and build U-Boot to some external directory:
5268 1. Add O= to the make command line invocations:
5270 make O=/tmp/build distclean
5271 make O=/tmp/build NAME_defconfig
5272 make O=/tmp/build all
5274 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
5276 export KBUILD_OUTPUT=/tmp/build
5281 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
5285 Please be aware that the Makefiles assume you are using GNU make, so
5286 for instance on NetBSD you might need to use "gmake" instead of
5290 If the system board that you have is not listed, then you will need
5291 to port U-Boot to your hardware platform. To do this, follow these
5294 1. Add a new configuration option for your board to the toplevel
5295 "boards.cfg" file, using the existing entries as examples.
5296 Follow the instructions there to keep the boards in order.
5297 2. Create a new directory to hold your board specific code. Add any
5298 files you need. In your board directory, you will need at least
5299 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
5300 3. Create a new configuration file "include/configs/<board>.h" for
5302 3. If you're porting U-Boot to a new CPU, then also create a new
5303 directory to hold your CPU specific code. Add any files you need.
5304 4. Run "make <board>_defconfig" with your new name.
5305 5. Type "make", and you should get a working "u-boot.srec" file
5306 to be installed on your target system.
5307 6. Debug and solve any problems that might arise.
5308 [Of course, this last step is much harder than it sounds.]
5311 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5312 ==============================================================
5314 If you have modified U-Boot sources (for instance added a new board
5315 or support for new devices, a new CPU, etc.) you are expected to
5316 provide feedback to the other developers. The feedback normally takes
5317 the form of a "patch", i. e. a context diff against a certain (latest
5318 official or latest in the git repository) version of U-Boot sources.
5320 But before you submit such a patch, please verify that your modifi-
5321 cation did not break existing code. At least make sure that *ALL* of
5322 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5323 just run the "MAKEALL" script, which will configure and build U-Boot
5324 for ALL supported system. Be warned, this will take a while. You can
5325 select which (cross) compiler to use by passing a `CROSS_COMPILE'
5326 environment variable to the script, i. e. to use the ELDK cross tools
5329 CROSS_COMPILE=ppc_8xx- MAKEALL
5331 or to build on a native PowerPC system you can type
5333 CROSS_COMPILE=' ' MAKEALL
5335 When using the MAKEALL script, the default behaviour is to build
5336 U-Boot in the source directory. This location can be changed by
5337 setting the BUILD_DIR environment variable. Also, for each target
5338 built, the MAKEALL script saves two log files (<target>.ERR and
5339 <target>.MAKEALL) in the <source dir>/LOG directory. This default
5340 location can be changed by setting the MAKEALL_LOGDIR environment
5341 variable. For example:
5343 export BUILD_DIR=/tmp/build
5344 export MAKEALL_LOGDIR=/tmp/log
5345 CROSS_COMPILE=ppc_8xx- MAKEALL
5347 With the above settings build objects are saved in the /tmp/build,
5348 log files are saved in the /tmp/log and the source tree remains clean
5349 during the whole build process.
5352 See also "U-Boot Porting Guide" below.
5355 Monitor Commands - Overview:
5356 ============================
5358 go - start application at address 'addr'
5359 run - run commands in an environment variable
5360 bootm - boot application image from memory
5361 bootp - boot image via network using BootP/TFTP protocol
5362 bootz - boot zImage from memory
5363 tftpboot- boot image via network using TFTP protocol
5364 and env variables "ipaddr" and "serverip"
5365 (and eventually "gatewayip")
5366 tftpput - upload a file via network using TFTP protocol
5367 rarpboot- boot image via network using RARP/TFTP protocol
5368 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5369 loads - load S-Record file over serial line
5370 loadb - load binary file over serial line (kermit mode)
5372 mm - memory modify (auto-incrementing)
5373 nm - memory modify (constant address)
5374 mw - memory write (fill)
5376 cmp - memory compare
5377 crc32 - checksum calculation
5378 i2c - I2C sub-system
5379 sspi - SPI utility commands
5380 base - print or set address offset
5381 printenv- print environment variables
5382 setenv - set environment variables
5383 saveenv - save environment variables to persistent storage
5384 protect - enable or disable FLASH write protection
5385 erase - erase FLASH memory
5386 flinfo - print FLASH memory information
5387 nand - NAND memory operations (see doc/README.nand)
5388 bdinfo - print Board Info structure
5389 iminfo - print header information for application image
5390 coninfo - print console devices and informations
5391 ide - IDE sub-system
5392 loop - infinite loop on address range
5393 loopw - infinite write loop on address range
5394 mtest - simple RAM test
5395 icache - enable or disable instruction cache
5396 dcache - enable or disable data cache
5397 reset - Perform RESET of the CPU
5398 echo - echo args to console
5399 version - print monitor version
5400 help - print online help
5401 ? - alias for 'help'
5404 Monitor Commands - Detailed Description:
5405 ========================================
5409 For now: just type "help <command>".
5412 Environment Variables:
5413 ======================
5415 U-Boot supports user configuration using Environment Variables which
5416 can be made persistent by saving to Flash memory.
5418 Environment Variables are set using "setenv", printed using
5419 "printenv", and saved to Flash using "saveenv". Using "setenv"
5420 without a value can be used to delete a variable from the
5421 environment. As long as you don't save the environment you are
5422 working with an in-memory copy. In case the Flash area containing the
5423 environment is erased by accident, a default environment is provided.
5425 Some configuration options can be set using Environment Variables.
5427 List of environment variables (most likely not complete):
5429 baudrate - see CONFIG_BAUDRATE
5431 bootdelay - see CONFIG_BOOTDELAY
5433 bootcmd - see CONFIG_BOOTCOMMAND
5435 bootargs - Boot arguments when booting an RTOS image
5437 bootfile - Name of the image to load with TFTP
5439 bootm_low - Memory range available for image processing in the bootm
5440 command can be restricted. This variable is given as
5441 a hexadecimal number and defines lowest address allowed
5442 for use by the bootm command. See also "bootm_size"
5443 environment variable. Address defined by "bootm_low" is
5444 also the base of the initial memory mapping for the Linux
5445 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5448 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5449 This variable is given as a hexadecimal number and it
5450 defines the size of the memory region starting at base
5451 address bootm_low that is accessible by the Linux kernel
5452 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5453 as the default value if it is defined, and bootm_size is
5456 bootm_size - Memory range available for image processing in the bootm
5457 command can be restricted. This variable is given as
5458 a hexadecimal number and defines the size of the region
5459 allowed for use by the bootm command. See also "bootm_low"
5460 environment variable.
5462 updatefile - Location of the software update file on a TFTP server, used
5463 by the automatic software update feature. Please refer to
5464 documentation in doc/README.update for more details.
5466 autoload - if set to "no" (any string beginning with 'n'),
5467 "bootp" will just load perform a lookup of the
5468 configuration from the BOOTP server, but not try to
5469 load any image using TFTP
5471 autostart - if set to "yes", an image loaded using the "bootp",
5472 "rarpboot", "tftpboot" or "diskboot" commands will
5473 be automatically started (by internally calling
5476 If set to "no", a standalone image passed to the
5477 "bootm" command will be copied to the load address
5478 (and eventually uncompressed), but NOT be started.
5479 This can be used to load and uncompress arbitrary
5482 fdt_high - if set this restricts the maximum address that the
5483 flattened device tree will be copied into upon boot.
5484 For example, if you have a system with 1 GB memory
5485 at physical address 0x10000000, while Linux kernel
5486 only recognizes the first 704 MB as low memory, you
5487 may need to set fdt_high as 0x3C000000 to have the
5488 device tree blob be copied to the maximum address
5489 of the 704 MB low memory, so that Linux kernel can
5490 access it during the boot procedure.
5492 If this is set to the special value 0xFFFFFFFF then
5493 the fdt will not be copied at all on boot. For this
5494 to work it must reside in writable memory, have
5495 sufficient padding on the end of it for u-boot to
5496 add the information it needs into it, and the memory
5497 must be accessible by the kernel.
5499 fdtcontroladdr- if set this is the address of the control flattened
5500 device tree used by U-Boot when CONFIG_OF_CONTROL is
5503 i2cfast - (PPC405GP|PPC405EP only)
5504 if set to 'y' configures Linux I2C driver for fast
5505 mode (400kHZ). This environment variable is used in
5506 initialization code. So, for changes to be effective
5507 it must be saved and board must be reset.
5509 initrd_high - restrict positioning of initrd images:
5510 If this variable is not set, initrd images will be
5511 copied to the highest possible address in RAM; this
5512 is usually what you want since it allows for
5513 maximum initrd size. If for some reason you want to
5514 make sure that the initrd image is loaded below the
5515 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5516 variable to a value of "no" or "off" or "0".
5517 Alternatively, you can set it to a maximum upper
5518 address to use (U-Boot will still check that it
5519 does not overwrite the U-Boot stack and data).
5521 For instance, when you have a system with 16 MB
5522 RAM, and want to reserve 4 MB from use by Linux,
5523 you can do this by adding "mem=12M" to the value of
5524 the "bootargs" variable. However, now you must make
5525 sure that the initrd image is placed in the first
5526 12 MB as well - this can be done with
5528 setenv initrd_high 00c00000
5530 If you set initrd_high to 0xFFFFFFFF, this is an
5531 indication to U-Boot that all addresses are legal
5532 for the Linux kernel, including addresses in flash
5533 memory. In this case U-Boot will NOT COPY the
5534 ramdisk at all. This may be useful to reduce the
5535 boot time on your system, but requires that this
5536 feature is supported by your Linux kernel.
5538 ipaddr - IP address; needed for tftpboot command
5540 loadaddr - Default load address for commands like "bootp",
5541 "rarpboot", "tftpboot", "loadb" or "diskboot"
5543 loads_echo - see CONFIG_LOADS_ECHO
5545 serverip - TFTP server IP address; needed for tftpboot command
5547 bootretry - see CONFIG_BOOT_RETRY_TIME
5549 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5551 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5553 ethprime - controls which interface is used first.
5555 ethact - controls which interface is currently active.
5556 For example you can do the following
5558 => setenv ethact FEC
5559 => ping 192.168.0.1 # traffic sent on FEC
5560 => setenv ethact SCC
5561 => ping 10.0.0.1 # traffic sent on SCC
5563 ethrotate - When set to "no" U-Boot does not go through all
5564 available network interfaces.
5565 It just stays at the currently selected interface.
5567 netretry - When set to "no" each network operation will
5568 either succeed or fail without retrying.
5569 When set to "once" the network operation will
5570 fail when all the available network interfaces
5571 are tried once without success.
5572 Useful on scripts which control the retry operation
5575 npe_ucode - set load address for the NPE microcode
5577 silent_linux - If set then Linux will be told to boot silently, by
5578 changing the console to be empty. If "yes" it will be
5579 made silent. If "no" it will not be made silent. If
5580 unset, then it will be made silent if the U-Boot console
5583 tftpsrcport - If this is set, the value is used for TFTP's
5586 tftpdstport - If this is set, the value is used for TFTP's UDP
5587 destination port instead of the Well Know Port 69.
5589 tftpblocksize - Block size to use for TFTP transfers; if not set,
5590 we use the TFTP server's default block size
5592 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5593 seconds, minimum value is 1000 = 1 second). Defines
5594 when a packet is considered to be lost so it has to
5595 be retransmitted. The default is 5000 = 5 seconds.
5596 Lowering this value may make downloads succeed
5597 faster in networks with high packet loss rates or
5598 with unreliable TFTP servers.
5600 vlan - When set to a value < 4095 the traffic over
5601 Ethernet is encapsulated/received over 802.1q
5604 The following image location variables contain the location of images
5605 used in booting. The "Image" column gives the role of the image and is
5606 not an environment variable name. The other columns are environment
5607 variable names. "File Name" gives the name of the file on a TFTP
5608 server, "RAM Address" gives the location in RAM the image will be
5609 loaded to, and "Flash Location" gives the image's address in NOR
5610 flash or offset in NAND flash.
5612 *Note* - these variables don't have to be defined for all boards, some
5613 boards currenlty use other variables for these purposes, and some
5614 boards use these variables for other purposes.
5616 Image File Name RAM Address Flash Location
5617 ----- --------- ----------- --------------
5618 u-boot u-boot u-boot_addr_r u-boot_addr
5619 Linux kernel bootfile kernel_addr_r kernel_addr
5620 device tree blob fdtfile fdt_addr_r fdt_addr
5621 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5623 The following environment variables may be used and automatically
5624 updated by the network boot commands ("bootp" and "rarpboot"),
5625 depending the information provided by your boot server:
5627 bootfile - see above
5628 dnsip - IP address of your Domain Name Server
5629 dnsip2 - IP address of your secondary Domain Name Server
5630 gatewayip - IP address of the Gateway (Router) to use
5631 hostname - Target hostname
5633 netmask - Subnet Mask
5634 rootpath - Pathname of the root filesystem on the NFS server
5635 serverip - see above
5638 There are two special Environment Variables:
5640 serial# - contains hardware identification information such
5641 as type string and/or serial number
5642 ethaddr - Ethernet address
5644 These variables can be set only once (usually during manufacturing of
5645 the board). U-Boot refuses to delete or overwrite these variables
5646 once they have been set once.
5649 Further special Environment Variables:
5651 ver - Contains the U-Boot version string as printed
5652 with the "version" command. This variable is
5653 readonly (see CONFIG_VERSION_VARIABLE).
5656 Please note that changes to some configuration parameters may take
5657 only effect after the next boot (yes, that's just like Windoze :-).
5660 Callback functions for environment variables:
5661 ---------------------------------------------
5663 For some environment variables, the behavior of u-boot needs to change
5664 when their values are changed. This functionality allows functions to
5665 be associated with arbitrary variables. On creation, overwrite, or
5666 deletion, the callback will provide the opportunity for some side
5667 effect to happen or for the change to be rejected.
5669 The callbacks are named and associated with a function using the
5670 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5672 These callbacks are associated with variables in one of two ways. The
5673 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5674 in the board configuration to a string that defines a list of
5675 associations. The list must be in the following format:
5677 entry = variable_name[:callback_name]
5680 If the callback name is not specified, then the callback is deleted.
5681 Spaces are also allowed anywhere in the list.
5683 Callbacks can also be associated by defining the ".callbacks" variable
5684 with the same list format above. Any association in ".callbacks" will
5685 override any association in the static list. You can define
5686 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5687 ".callbacks" environment variable in the default or embedded environment.
5690 Command Line Parsing:
5691 =====================
5693 There are two different command line parsers available with U-Boot:
5694 the old "simple" one, and the much more powerful "hush" shell:
5696 Old, simple command line parser:
5697 --------------------------------
5699 - supports environment variables (through setenv / saveenv commands)
5700 - several commands on one line, separated by ';'
5701 - variable substitution using "... ${name} ..." syntax
5702 - special characters ('$', ';') can be escaped by prefixing with '\',
5704 setenv bootcmd bootm \${address}
5705 - You can also escape text by enclosing in single apostrophes, for example:
5706 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5711 - similar to Bourne shell, with control structures like
5712 if...then...else...fi, for...do...done; while...do...done,
5713 until...do...done, ...
5714 - supports environment ("global") variables (through setenv / saveenv
5715 commands) and local shell variables (through standard shell syntax
5716 "name=value"); only environment variables can be used with "run"
5722 (1) If a command line (or an environment variable executed by a "run"
5723 command) contains several commands separated by semicolon, and
5724 one of these commands fails, then the remaining commands will be
5727 (2) If you execute several variables with one call to run (i. e.
5728 calling run with a list of variables as arguments), any failing
5729 command will cause "run" to terminate, i. e. the remaining
5730 variables are not executed.
5732 Note for Redundant Ethernet Interfaces:
5733 =======================================
5735 Some boards come with redundant Ethernet interfaces; U-Boot supports
5736 such configurations and is capable of automatic selection of a
5737 "working" interface when needed. MAC assignment works as follows:
5739 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5740 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5741 "eth1addr" (=>eth1), "eth2addr", ...
5743 If the network interface stores some valid MAC address (for instance
5744 in SROM), this is used as default address if there is NO correspon-
5745 ding setting in the environment; if the corresponding environment
5746 variable is set, this overrides the settings in the card; that means:
5748 o If the SROM has a valid MAC address, and there is no address in the
5749 environment, the SROM's address is used.
5751 o If there is no valid address in the SROM, and a definition in the
5752 environment exists, then the value from the environment variable is
5755 o If both the SROM and the environment contain a MAC address, and
5756 both addresses are the same, this MAC address is used.
5758 o If both the SROM and the environment contain a MAC address, and the
5759 addresses differ, the value from the environment is used and a
5762 o If neither SROM nor the environment contain a MAC address, an error
5765 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5766 will be programmed into hardware as part of the initialization process. This
5767 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5768 The naming convention is as follows:
5769 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5774 U-Boot is capable of booting (and performing other auxiliary operations on)
5775 images in two formats:
5777 New uImage format (FIT)
5778 -----------------------
5780 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5781 to Flattened Device Tree). It allows the use of images with multiple
5782 components (several kernels, ramdisks, etc.), with contents protected by
5783 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5789 Old image format is based on binary files which can be basically anything,
5790 preceded by a special header; see the definitions in include/image.h for
5791 details; basically, the header defines the following image properties:
5793 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5794 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5795 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5796 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5798 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5799 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5800 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5801 * Compression Type (uncompressed, gzip, bzip2)
5807 The header is marked by a special Magic Number, and both the header
5808 and the data portions of the image are secured against corruption by
5815 Although U-Boot should support any OS or standalone application
5816 easily, the main focus has always been on Linux during the design of
5819 U-Boot includes many features that so far have been part of some
5820 special "boot loader" code within the Linux kernel. Also, any
5821 "initrd" images to be used are no longer part of one big Linux image;
5822 instead, kernel and "initrd" are separate images. This implementation
5823 serves several purposes:
5825 - the same features can be used for other OS or standalone
5826 applications (for instance: using compressed images to reduce the
5827 Flash memory footprint)
5829 - it becomes much easier to port new Linux kernel versions because
5830 lots of low-level, hardware dependent stuff are done by U-Boot
5832 - the same Linux kernel image can now be used with different "initrd"
5833 images; of course this also means that different kernel images can
5834 be run with the same "initrd". This makes testing easier (you don't
5835 have to build a new "zImage.initrd" Linux image when you just
5836 change a file in your "initrd"). Also, a field-upgrade of the
5837 software is easier now.
5843 Porting Linux to U-Boot based systems:
5844 ---------------------------------------
5846 U-Boot cannot save you from doing all the necessary modifications to
5847 configure the Linux device drivers for use with your target hardware
5848 (no, we don't intend to provide a full virtual machine interface to
5851 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5853 Just make sure your machine specific header file (for instance
5854 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5855 Information structure as we define in include/asm-<arch>/u-boot.h,
5856 and make sure that your definition of IMAP_ADDR uses the same value
5857 as your U-Boot configuration in CONFIG_SYS_IMMR.
5859 Note that U-Boot now has a driver model, a unified model for drivers.
5860 If you are adding a new driver, plumb it into driver model. If there
5861 is no uclass available, you are encouraged to create one. See
5865 Configuring the Linux kernel:
5866 -----------------------------
5868 No specific requirements for U-Boot. Make sure you have some root
5869 device (initial ramdisk, NFS) for your target system.
5872 Building a Linux Image:
5873 -----------------------
5875 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5876 not used. If you use recent kernel source, a new build target
5877 "uImage" will exist which automatically builds an image usable by
5878 U-Boot. Most older kernels also have support for a "pImage" target,
5879 which was introduced for our predecessor project PPCBoot and uses a
5880 100% compatible format.
5884 make TQM850L_defconfig
5889 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5890 encapsulate a compressed Linux kernel image with header information,
5891 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5893 * build a standard "vmlinux" kernel image (in ELF binary format):
5895 * convert the kernel into a raw binary image:
5897 ${CROSS_COMPILE}-objcopy -O binary \
5898 -R .note -R .comment \
5899 -S vmlinux linux.bin
5901 * compress the binary image:
5905 * package compressed binary image for U-Boot:
5907 mkimage -A ppc -O linux -T kernel -C gzip \
5908 -a 0 -e 0 -n "Linux Kernel Image" \
5909 -d linux.bin.gz uImage
5912 The "mkimage" tool can also be used to create ramdisk images for use
5913 with U-Boot, either separated from the Linux kernel image, or
5914 combined into one file. "mkimage" encapsulates the images with a 64
5915 byte header containing information about target architecture,
5916 operating system, image type, compression method, entry points, time
5917 stamp, CRC32 checksums, etc.
5919 "mkimage" can be called in two ways: to verify existing images and
5920 print the header information, or to build new images.
5922 In the first form (with "-l" option) mkimage lists the information
5923 contained in the header of an existing U-Boot image; this includes
5924 checksum verification:
5926 tools/mkimage -l image
5927 -l ==> list image header information
5929 The second form (with "-d" option) is used to build a U-Boot image
5930 from a "data file" which is used as image payload:
5932 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5933 -n name -d data_file image
5934 -A ==> set architecture to 'arch'
5935 -O ==> set operating system to 'os'
5936 -T ==> set image type to 'type'
5937 -C ==> set compression type 'comp'
5938 -a ==> set load address to 'addr' (hex)
5939 -e ==> set entry point to 'ep' (hex)
5940 -n ==> set image name to 'name'
5941 -d ==> use image data from 'datafile'
5943 Right now, all Linux kernels for PowerPC systems use the same load
5944 address (0x00000000), but the entry point address depends on the
5947 - 2.2.x kernels have the entry point at 0x0000000C,
5948 - 2.3.x and later kernels have the entry point at 0x00000000.
5950 So a typical call to build a U-Boot image would read:
5952 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5953 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5954 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5955 > examples/uImage.TQM850L
5956 Image Name: 2.4.4 kernel for TQM850L
5957 Created: Wed Jul 19 02:34:59 2000
5958 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5959 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5960 Load Address: 0x00000000
5961 Entry Point: 0x00000000
5963 To verify the contents of the image (or check for corruption):
5965 -> tools/mkimage -l examples/uImage.TQM850L
5966 Image Name: 2.4.4 kernel for TQM850L
5967 Created: Wed Jul 19 02:34:59 2000
5968 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5969 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5970 Load Address: 0x00000000
5971 Entry Point: 0x00000000
5973 NOTE: for embedded systems where boot time is critical you can trade
5974 speed for memory and install an UNCOMPRESSED image instead: this
5975 needs more space in Flash, but boots much faster since it does not
5976 need to be uncompressed:
5978 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5979 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5980 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5981 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5982 > examples/uImage.TQM850L-uncompressed
5983 Image Name: 2.4.4 kernel for TQM850L
5984 Created: Wed Jul 19 02:34:59 2000
5985 Image Type: PowerPC Linux Kernel Image (uncompressed)
5986 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5987 Load Address: 0x00000000
5988 Entry Point: 0x00000000
5991 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5992 when your kernel is intended to use an initial ramdisk:
5994 -> tools/mkimage -n 'Simple Ramdisk Image' \
5995 > -A ppc -O linux -T ramdisk -C gzip \
5996 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5997 Image Name: Simple Ramdisk Image
5998 Created: Wed Jan 12 14:01:50 2000
5999 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6000 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
6001 Load Address: 0x00000000
6002 Entry Point: 0x00000000
6004 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
6005 option performs the converse operation of the mkimage's second form (the "-d"
6006 option). Given an image built by mkimage, the dumpimage extracts a "data file"
6009 tools/dumpimage -i image -T type -p position data_file
6010 -i ==> extract from the 'image' a specific 'data_file'
6011 -T ==> set image type to 'type'
6012 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
6015 Installing a Linux Image:
6016 -------------------------
6018 To downloading a U-Boot image over the serial (console) interface,
6019 you must convert the image to S-Record format:
6021 objcopy -I binary -O srec examples/image examples/image.srec
6023 The 'objcopy' does not understand the information in the U-Boot
6024 image header, so the resulting S-Record file will be relative to
6025 address 0x00000000. To load it to a given address, you need to
6026 specify the target address as 'offset' parameter with the 'loads'
6029 Example: install the image to address 0x40100000 (which on the
6030 TQM8xxL is in the first Flash bank):
6032 => erase 40100000 401FFFFF
6038 ## Ready for S-Record download ...
6039 ~>examples/image.srec
6040 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
6042 15989 15990 15991 15992
6043 [file transfer complete]
6045 ## Start Addr = 0x00000000
6048 You can check the success of the download using the 'iminfo' command;
6049 this includes a checksum verification so you can be sure no data
6050 corruption happened:
6054 ## Checking Image at 40100000 ...
6055 Image Name: 2.2.13 for initrd on TQM850L
6056 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6057 Data Size: 335725 Bytes = 327 kB = 0 MB
6058 Load Address: 00000000
6059 Entry Point: 0000000c
6060 Verifying Checksum ... OK
6066 The "bootm" command is used to boot an application that is stored in
6067 memory (RAM or Flash). In case of a Linux kernel image, the contents
6068 of the "bootargs" environment variable is passed to the kernel as
6069 parameters. You can check and modify this variable using the
6070 "printenv" and "setenv" commands:
6073 => printenv bootargs
6074 bootargs=root=/dev/ram
6076 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6078 => printenv bootargs
6079 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6082 ## Booting Linux kernel at 40020000 ...
6083 Image Name: 2.2.13 for NFS on TQM850L
6084 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6085 Data Size: 381681 Bytes = 372 kB = 0 MB
6086 Load Address: 00000000
6087 Entry Point: 0000000c
6088 Verifying Checksum ... OK
6089 Uncompressing Kernel Image ... OK
6090 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
6091 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
6092 time_init: decrementer frequency = 187500000/60
6093 Calibrating delay loop... 49.77 BogoMIPS
6094 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
6097 If you want to boot a Linux kernel with initial RAM disk, you pass
6098 the memory addresses of both the kernel and the initrd image (PPBCOOT
6099 format!) to the "bootm" command:
6101 => imi 40100000 40200000
6103 ## Checking Image at 40100000 ...
6104 Image Name: 2.2.13 for initrd on TQM850L
6105 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6106 Data Size: 335725 Bytes = 327 kB = 0 MB
6107 Load Address: 00000000
6108 Entry Point: 0000000c
6109 Verifying Checksum ... OK
6111 ## Checking Image at 40200000 ...
6112 Image Name: Simple Ramdisk Image
6113 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6114 Data Size: 566530 Bytes = 553 kB = 0 MB
6115 Load Address: 00000000
6116 Entry Point: 00000000
6117 Verifying Checksum ... OK
6119 => bootm 40100000 40200000
6120 ## Booting Linux kernel at 40100000 ...
6121 Image Name: 2.2.13 for initrd on TQM850L
6122 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6123 Data Size: 335725 Bytes = 327 kB = 0 MB
6124 Load Address: 00000000
6125 Entry Point: 0000000c
6126 Verifying Checksum ... OK
6127 Uncompressing Kernel Image ... OK
6128 ## Loading RAMDisk Image at 40200000 ...
6129 Image Name: Simple Ramdisk Image
6130 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6131 Data Size: 566530 Bytes = 553 kB = 0 MB
6132 Load Address: 00000000
6133 Entry Point: 00000000
6134 Verifying Checksum ... OK
6135 Loading Ramdisk ... OK
6136 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
6137 Boot arguments: root=/dev/ram
6138 time_init: decrementer frequency = 187500000/60
6139 Calibrating delay loop... 49.77 BogoMIPS
6141 RAMDISK: Compressed image found at block 0
6142 VFS: Mounted root (ext2 filesystem).
6146 Boot Linux and pass a flat device tree:
6149 First, U-Boot must be compiled with the appropriate defines. See the section
6150 titled "Linux Kernel Interface" above for a more in depth explanation. The
6151 following is an example of how to start a kernel and pass an updated
6157 oft=oftrees/mpc8540ads.dtb
6158 => tftp $oftaddr $oft
6159 Speed: 1000, full duplex
6161 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
6162 Filename 'oftrees/mpc8540ads.dtb'.
6163 Load address: 0x300000
6166 Bytes transferred = 4106 (100a hex)
6167 => tftp $loadaddr $bootfile
6168 Speed: 1000, full duplex
6170 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
6172 Load address: 0x200000
6173 Loading:############
6175 Bytes transferred = 1029407 (fb51f hex)
6180 => bootm $loadaddr - $oftaddr
6181 ## Booting image at 00200000 ...
6182 Image Name: Linux-2.6.17-dirty
6183 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6184 Data Size: 1029343 Bytes = 1005.2 kB
6185 Load Address: 00000000
6186 Entry Point: 00000000
6187 Verifying Checksum ... OK
6188 Uncompressing Kernel Image ... OK
6189 Booting using flat device tree at 0x300000
6190 Using MPC85xx ADS machine description
6191 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
6195 More About U-Boot Image Types:
6196 ------------------------------
6198 U-Boot supports the following image types:
6200 "Standalone Programs" are directly runnable in the environment
6201 provided by U-Boot; it is expected that (if they behave
6202 well) you can continue to work in U-Boot after return from
6203 the Standalone Program.
6204 "OS Kernel Images" are usually images of some Embedded OS which
6205 will take over control completely. Usually these programs
6206 will install their own set of exception handlers, device
6207 drivers, set up the MMU, etc. - this means, that you cannot
6208 expect to re-enter U-Boot except by resetting the CPU.
6209 "RAMDisk Images" are more or less just data blocks, and their
6210 parameters (address, size) are passed to an OS kernel that is
6212 "Multi-File Images" contain several images, typically an OS
6213 (Linux) kernel image and one or more data images like
6214 RAMDisks. This construct is useful for instance when you want
6215 to boot over the network using BOOTP etc., where the boot
6216 server provides just a single image file, but you want to get
6217 for instance an OS kernel and a RAMDisk image.
6219 "Multi-File Images" start with a list of image sizes, each
6220 image size (in bytes) specified by an "uint32_t" in network
6221 byte order. This list is terminated by an "(uint32_t)0".
6222 Immediately after the terminating 0 follow the images, one by
6223 one, all aligned on "uint32_t" boundaries (size rounded up to
6224 a multiple of 4 bytes).
6226 "Firmware Images" are binary images containing firmware (like
6227 U-Boot or FPGA images) which usually will be programmed to
6230 "Script files" are command sequences that will be executed by
6231 U-Boot's command interpreter; this feature is especially
6232 useful when you configure U-Boot to use a real shell (hush)
6233 as command interpreter.
6235 Booting the Linux zImage:
6236 -------------------------
6238 On some platforms, it's possible to boot Linux zImage. This is done
6239 using the "bootz" command. The syntax of "bootz" command is the same
6240 as the syntax of "bootm" command.
6242 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
6243 kernel with raw initrd images. The syntax is slightly different, the
6244 address of the initrd must be augmented by it's size, in the following
6245 format: "<initrd addres>:<initrd size>".
6251 One of the features of U-Boot is that you can dynamically load and
6252 run "standalone" applications, which can use some resources of
6253 U-Boot like console I/O functions or interrupt services.
6255 Two simple examples are included with the sources:
6260 'examples/hello_world.c' contains a small "Hello World" Demo
6261 application; it is automatically compiled when you build U-Boot.
6262 It's configured to run at address 0x00040004, so you can play with it
6266 ## Ready for S-Record download ...
6267 ~>examples/hello_world.srec
6268 1 2 3 4 5 6 7 8 9 10 11 ...
6269 [file transfer complete]
6271 ## Start Addr = 0x00040004
6273 => go 40004 Hello World! This is a test.
6274 ## Starting application at 0x00040004 ...
6285 Hit any key to exit ...
6287 ## Application terminated, rc = 0x0
6289 Another example, which demonstrates how to register a CPM interrupt
6290 handler with the U-Boot code, can be found in 'examples/timer.c'.
6291 Here, a CPM timer is set up to generate an interrupt every second.
6292 The interrupt service routine is trivial, just printing a '.'
6293 character, but this is just a demo program. The application can be
6294 controlled by the following keys:
6296 ? - print current values og the CPM Timer registers
6297 b - enable interrupts and start timer
6298 e - stop timer and disable interrupts
6299 q - quit application
6302 ## Ready for S-Record download ...
6303 ~>examples/timer.srec
6304 1 2 3 4 5 6 7 8 9 10 11 ...
6305 [file transfer complete]
6307 ## Start Addr = 0x00040004
6310 ## Starting application at 0x00040004 ...
6313 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6316 [q, b, e, ?] Set interval 1000000 us
6319 [q, b, e, ?] ........
6320 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6323 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6326 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6329 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6331 [q, b, e, ?] ...Stopping timer
6333 [q, b, e, ?] ## Application terminated, rc = 0x0
6339 Over time, many people have reported problems when trying to use the
6340 "minicom" terminal emulation program for serial download. I (wd)
6341 consider minicom to be broken, and recommend not to use it. Under
6342 Unix, I recommend to use C-Kermit for general purpose use (and
6343 especially for kermit binary protocol download ("loadb" command), and
6344 use "cu" for S-Record download ("loads" command). See
6345 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6346 for help with kermit.
6349 Nevertheless, if you absolutely want to use it try adding this
6350 configuration to your "File transfer protocols" section:
6352 Name Program Name U/D FullScr IO-Red. Multi
6353 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6354 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6360 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6361 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6363 Building requires a cross environment; it is known to work on
6364 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6365 need gmake since the Makefiles are not compatible with BSD make).
6366 Note that the cross-powerpc package does not install include files;
6367 attempting to build U-Boot will fail because <machine/ansi.h> is
6368 missing. This file has to be installed and patched manually:
6370 # cd /usr/pkg/cross/powerpc-netbsd/include
6372 # ln -s powerpc machine
6373 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6374 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6376 Native builds *don't* work due to incompatibilities between native
6377 and U-Boot include files.
6379 Booting assumes that (the first part of) the image booted is a
6380 stage-2 loader which in turn loads and then invokes the kernel
6381 proper. Loader sources will eventually appear in the NetBSD source
6382 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6383 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6386 Implementation Internals:
6387 =========================
6389 The following is not intended to be a complete description of every
6390 implementation detail. However, it should help to understand the
6391 inner workings of U-Boot and make it easier to port it to custom
6395 Initial Stack, Global Data:
6396 ---------------------------
6398 The implementation of U-Boot is complicated by the fact that U-Boot
6399 starts running out of ROM (flash memory), usually without access to
6400 system RAM (because the memory controller is not initialized yet).
6401 This means that we don't have writable Data or BSS segments, and BSS
6402 is not initialized as zero. To be able to get a C environment working
6403 at all, we have to allocate at least a minimal stack. Implementation
6404 options for this are defined and restricted by the CPU used: Some CPU
6405 models provide on-chip memory (like the IMMR area on MPC8xx and
6406 MPC826x processors), on others (parts of) the data cache can be
6407 locked as (mis-) used as memory, etc.
6409 Chris Hallinan posted a good summary of these issues to the
6410 U-Boot mailing list:
6412 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6413 From: "Chris Hallinan" <clh@net1plus.com>
6414 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6417 Correct me if I'm wrong, folks, but the way I understand it
6418 is this: Using DCACHE as initial RAM for Stack, etc, does not
6419 require any physical RAM backing up the cache. The cleverness
6420 is that the cache is being used as a temporary supply of
6421 necessary storage before the SDRAM controller is setup. It's
6422 beyond the scope of this list to explain the details, but you
6423 can see how this works by studying the cache architecture and
6424 operation in the architecture and processor-specific manuals.
6426 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6427 is another option for the system designer to use as an
6428 initial stack/RAM area prior to SDRAM being available. Either
6429 option should work for you. Using CS 4 should be fine if your
6430 board designers haven't used it for something that would
6431 cause you grief during the initial boot! It is frequently not
6434 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6435 with your processor/board/system design. The default value
6436 you will find in any recent u-boot distribution in
6437 walnut.h should work for you. I'd set it to a value larger
6438 than your SDRAM module. If you have a 64MB SDRAM module, set
6439 it above 400_0000. Just make sure your board has no resources
6440 that are supposed to respond to that address! That code in
6441 start.S has been around a while and should work as is when
6442 you get the config right.
6447 It is essential to remember this, since it has some impact on the C
6448 code for the initialization procedures:
6450 * Initialized global data (data segment) is read-only. Do not attempt
6453 * Do not use any uninitialized global data (or implicitly initialized
6454 as zero data - BSS segment) at all - this is undefined, initiali-
6455 zation is performed later (when relocating to RAM).
6457 * Stack space is very limited. Avoid big data buffers or things like
6460 Having only the stack as writable memory limits means we cannot use
6461 normal global data to share information between the code. But it
6462 turned out that the implementation of U-Boot can be greatly
6463 simplified by making a global data structure (gd_t) available to all
6464 functions. We could pass a pointer to this data as argument to _all_
6465 functions, but this would bloat the code. Instead we use a feature of
6466 the GCC compiler (Global Register Variables) to share the data: we
6467 place a pointer (gd) to the global data into a register which we
6468 reserve for this purpose.
6470 When choosing a register for such a purpose we are restricted by the
6471 relevant (E)ABI specifications for the current architecture, and by
6472 GCC's implementation.
6474 For PowerPC, the following registers have specific use:
6476 R2: reserved for system use
6477 R3-R4: parameter passing and return values
6478 R5-R10: parameter passing
6479 R13: small data area pointer
6483 (U-Boot also uses R12 as internal GOT pointer. r12
6484 is a volatile register so r12 needs to be reset when
6485 going back and forth between asm and C)
6487 ==> U-Boot will use R2 to hold a pointer to the global data
6489 Note: on PPC, we could use a static initializer (since the
6490 address of the global data structure is known at compile time),
6491 but it turned out that reserving a register results in somewhat
6492 smaller code - although the code savings are not that big (on
6493 average for all boards 752 bytes for the whole U-Boot image,
6494 624 text + 127 data).
6496 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6497 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6499 ==> U-Boot will use P3 to hold a pointer to the global data
6501 On ARM, the following registers are used:
6503 R0: function argument word/integer result
6504 R1-R3: function argument word
6505 R9: platform specific
6506 R10: stack limit (used only if stack checking is enabled)
6507 R11: argument (frame) pointer
6508 R12: temporary workspace
6511 R15: program counter
6513 ==> U-Boot will use R9 to hold a pointer to the global data
6515 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6517 On Nios II, the ABI is documented here:
6518 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6520 ==> U-Boot will use gp to hold a pointer to the global data
6522 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6523 to access small data sections, so gp is free.
6525 On NDS32, the following registers are used:
6527 R0-R1: argument/return
6529 R15: temporary register for assembler
6530 R16: trampoline register
6531 R28: frame pointer (FP)
6532 R29: global pointer (GP)
6533 R30: link register (LP)
6534 R31: stack pointer (SP)
6535 PC: program counter (PC)
6537 ==> U-Boot will use R10 to hold a pointer to the global data
6539 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6540 or current versions of GCC may "optimize" the code too much.
6545 U-Boot runs in system state and uses physical addresses, i.e. the
6546 MMU is not used either for address mapping nor for memory protection.
6548 The available memory is mapped to fixed addresses using the memory
6549 controller. In this process, a contiguous block is formed for each
6550 memory type (Flash, SDRAM, SRAM), even when it consists of several
6551 physical memory banks.
6553 U-Boot is installed in the first 128 kB of the first Flash bank (on
6554 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6555 booting and sizing and initializing DRAM, the code relocates itself
6556 to the upper end of DRAM. Immediately below the U-Boot code some
6557 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6558 configuration setting]. Below that, a structure with global Board
6559 Info data is placed, followed by the stack (growing downward).
6561 Additionally, some exception handler code is copied to the low 8 kB
6562 of DRAM (0x00000000 ... 0x00001FFF).
6564 So a typical memory configuration with 16 MB of DRAM could look like
6567 0x0000 0000 Exception Vector code
6570 0x0000 2000 Free for Application Use
6576 0x00FB FF20 Monitor Stack (Growing downward)
6577 0x00FB FFAC Board Info Data and permanent copy of global data
6578 0x00FC 0000 Malloc Arena
6581 0x00FE 0000 RAM Copy of Monitor Code
6582 ... eventually: LCD or video framebuffer
6583 ... eventually: pRAM (Protected RAM - unchanged by reset)
6584 0x00FF FFFF [End of RAM]
6587 System Initialization:
6588 ----------------------
6590 In the reset configuration, U-Boot starts at the reset entry point
6591 (on most PowerPC systems at address 0x00000100). Because of the reset
6592 configuration for CS0# this is a mirror of the on board Flash memory.
6593 To be able to re-map memory U-Boot then jumps to its link address.
6594 To be able to implement the initialization code in C, a (small!)
6595 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6596 which provide such a feature like MPC8xx or MPC8260), or in a locked
6597 part of the data cache. After that, U-Boot initializes the CPU core,
6598 the caches and the SIU.
6600 Next, all (potentially) available memory banks are mapped using a
6601 preliminary mapping. For example, we put them on 512 MB boundaries
6602 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6603 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6604 programmed for SDRAM access. Using the temporary configuration, a
6605 simple memory test is run that determines the size of the SDRAM
6608 When there is more than one SDRAM bank, and the banks are of
6609 different size, the largest is mapped first. For equal size, the first
6610 bank (CS2#) is mapped first. The first mapping is always for address
6611 0x00000000, with any additional banks following immediately to create
6612 contiguous memory starting from 0.
6614 Then, the monitor installs itself at the upper end of the SDRAM area
6615 and allocates memory for use by malloc() and for the global Board
6616 Info data; also, the exception vector code is copied to the low RAM
6617 pages, and the final stack is set up.
6619 Only after this relocation will you have a "normal" C environment;
6620 until that you are restricted in several ways, mostly because you are
6621 running from ROM, and because the code will have to be relocated to a
6625 U-Boot Porting Guide:
6626 ----------------------
6628 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6632 int main(int argc, char *argv[])
6634 sighandler_t no_more_time;
6636 signal(SIGALRM, no_more_time);
6637 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6639 if (available_money > available_manpower) {
6640 Pay consultant to port U-Boot;
6644 Download latest U-Boot source;
6646 Subscribe to u-boot mailing list;
6649 email("Hi, I am new to U-Boot, how do I get started?");
6652 Read the README file in the top level directory;
6653 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6654 Read applicable doc/*.README;
6655 Read the source, Luke;
6656 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6659 if (available_money > toLocalCurrency ($2500))
6662 Add a lot of aggravation and time;
6664 if (a similar board exists) { /* hopefully... */
6665 cp -a board/<similar> board/<myboard>
6666 cp include/configs/<similar>.h include/configs/<myboard>.h
6668 Create your own board support subdirectory;
6669 Create your own board include/configs/<myboard>.h file;
6671 Edit new board/<myboard> files
6672 Edit new include/configs/<myboard>.h
6677 Add / modify source code;
6681 email("Hi, I am having problems...");
6683 Send patch file to the U-Boot email list;
6684 if (reasonable critiques)
6685 Incorporate improvements from email list code review;
6687 Defend code as written;
6693 void no_more_time (int sig)
6702 All contributions to U-Boot should conform to the Linux kernel
6703 coding style; see the file "Documentation/CodingStyle" and the script
6704 "scripts/Lindent" in your Linux kernel source directory.
6706 Source files originating from a different project (for example the
6707 MTD subsystem) are generally exempt from these guidelines and are not
6708 reformatted to ease subsequent migration to newer versions of those
6711 Please note that U-Boot is implemented in C (and to some small parts in
6712 Assembler); no C++ is used, so please do not use C++ style comments (//)
6715 Please also stick to the following formatting rules:
6716 - remove any trailing white space
6717 - use TAB characters for indentation and vertical alignment, not spaces
6718 - make sure NOT to use DOS '\r\n' line feeds
6719 - do not add more than 2 consecutive empty lines to source files
6720 - do not add trailing empty lines to source files
6722 Submissions which do not conform to the standards may be returned
6723 with a request to reformat the changes.
6729 Since the number of patches for U-Boot is growing, we need to
6730 establish some rules. Submissions which do not conform to these rules
6731 may be rejected, even when they contain important and valuable stuff.
6733 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6735 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6736 see http://lists.denx.de/mailman/listinfo/u-boot
6738 When you send a patch, please include the following information with
6741 * For bug fixes: a description of the bug and how your patch fixes
6742 this bug. Please try to include a way of demonstrating that the
6743 patch actually fixes something.
6745 * For new features: a description of the feature and your
6748 * A CHANGELOG entry as plaintext (separate from the patch)
6750 * For major contributions, your entry to the CREDITS file
6752 * When you add support for a new board, don't forget to add a
6753 maintainer e-mail address to the boards.cfg file, too.
6755 * If your patch adds new configuration options, don't forget to
6756 document these in the README file.
6758 * The patch itself. If you are using git (which is *strongly*
6759 recommended) you can easily generate the patch using the
6760 "git format-patch". If you then use "git send-email" to send it to
6761 the U-Boot mailing list, you will avoid most of the common problems
6762 with some other mail clients.
6764 If you cannot use git, use "diff -purN OLD NEW". If your version of
6765 diff does not support these options, then get the latest version of
6768 The current directory when running this command shall be the parent
6769 directory of the U-Boot source tree (i. e. please make sure that
6770 your patch includes sufficient directory information for the
6773 We prefer patches as plain text. MIME attachments are discouraged,
6774 and compressed attachments must not be used.
6776 * If one logical set of modifications affects or creates several
6777 files, all these changes shall be submitted in a SINGLE patch file.
6779 * Changesets that contain different, unrelated modifications shall be
6780 submitted as SEPARATE patches, one patch per changeset.
6785 * Before sending the patch, run the MAKEALL script on your patched
6786 source tree and make sure that no errors or warnings are reported
6787 for any of the boards.
6789 * Keep your modifications to the necessary minimum: A patch
6790 containing several unrelated changes or arbitrary reformats will be
6791 returned with a request to re-formatting / split it.
6793 * If you modify existing code, make sure that your new code does not
6794 add to the memory footprint of the code ;-) Small is beautiful!
6795 When adding new features, these should compile conditionally only
6796 (using #ifdef), and the resulting code with the new feature
6797 disabled must not need more memory than the old code without your
6800 * Remember that there is a size limit of 100 kB per message on the
6801 u-boot mailing list. Bigger patches will be moderated. If they are
6802 reasonable and not too big, they will be acknowledged. But patches
6803 bigger than the size limit should be avoided.