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 file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /avr32 Files generic to AVR32 architecture
140 /blackfin Files generic to Analog Devices Blackfin architecture
141 /m68k Files generic to m68k architecture
142 /microblaze Files generic to microblaze architecture
143 /mips Files generic to MIPS architecture
144 /nds32 Files generic to NDS32 architecture
145 /nios2 Files generic to Altera NIOS2 architecture
146 /openrisc Files generic to OpenRISC architecture
147 /powerpc Files generic to PowerPC architecture
148 /sandbox Files generic to HW-independent "sandbox"
149 /sh Files generic to SH architecture
150 /sparc Files generic to SPARC architecture
151 /x86 Files generic to x86 architecture
152 /api Machine/arch independent API for external apps
153 /board Board dependent files
154 /cmd U-Boot commands functions
155 /common Misc architecture independent functions
156 /configs Board default configuration files
157 /disk Code for disk drive partition handling
158 /doc Documentation (don't expect too much)
159 /drivers Commonly used device drivers
160 /dts Contains Makefile for building internal U-Boot fdt.
161 /examples Example code for standalone applications, etc.
162 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
163 /include Header Files
164 /lib Library routines generic to all architectures
165 /Licenses Various license files
167 /post Power On Self Test
168 /scripts Various build scripts and Makefiles
169 /test Various unit test files
170 /tools Tools to build S-Record or U-Boot images, etc.
172 Software Configuration:
173 =======================
175 Configuration is usually done using C preprocessor defines; the
176 rationale behind that is to avoid dead code whenever possible.
178 There are two classes of configuration variables:
180 * Configuration _OPTIONS_:
181 These are selectable by the user and have names beginning with
184 * Configuration _SETTINGS_:
185 These depend on the hardware etc. and should not be meddled with if
186 you don't know what you're doing; they have names beginning with
189 Previously, all configuration was done by hand, which involved creating
190 symbolic links and editing configuration files manually. More recently,
191 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
192 allowing you to use the "make menuconfig" command to configure your
196 Selection of Processor Architecture and Board Type:
197 ---------------------------------------------------
199 For all supported boards there are ready-to-use default
200 configurations available; just type "make <board_name>_defconfig".
202 Example: For a TQM823L module type:
205 make TQM823L_defconfig
207 Note: If you're looking for the default configuration file for a board
208 you're sure used to be there but is now missing, check the file
209 doc/README.scrapyard for a list of no longer supported boards.
214 U-Boot can be built natively to run on a Linux host using the 'sandbox'
215 board. This allows feature development which is not board- or architecture-
216 specific to be undertaken on a native platform. The sandbox is also used to
217 run some of U-Boot's tests.
219 See board/sandbox/README.sandbox for more details.
222 Board Initialisation Flow:
223 --------------------------
225 This is the intended start-up flow for boards. This should apply for both
226 SPL and U-Boot proper (i.e. they both follow the same rules).
228 Note: "SPL" stands for "Secondary Program Loader," which is explained in
229 more detail later in this file.
231 At present, SPL mostly uses a separate code path, but the function names
232 and roles of each function are the same. Some boards or architectures
233 may not conform to this. At least most ARM boards which use
234 CONFIG_SPL_FRAMEWORK conform to this.
236 Execution typically starts with an architecture-specific (and possibly
237 CPU-specific) start.S file, such as:
239 - arch/arm/cpu/armv7/start.S
240 - arch/powerpc/cpu/mpc83xx/start.S
241 - arch/mips/cpu/start.S
243 and so on. From there, three functions are called; the purpose and
244 limitations of each of these functions are described below.
247 - purpose: essential init to permit execution to reach board_init_f()
248 - no global_data or BSS
249 - there is no stack (ARMv7 may have one but it will soon be removed)
250 - must not set up SDRAM or use console
251 - must only do the bare minimum to allow execution to continue to
253 - this is almost never needed
254 - return normally from this function
257 - purpose: set up the machine ready for running board_init_r():
258 i.e. SDRAM and serial UART
259 - global_data is available
261 - BSS is not available, so you cannot use global/static variables,
262 only stack variables and global_data
264 Non-SPL-specific notes:
265 - dram_init() is called to set up DRAM. If already done in SPL this
269 - you can override the entire board_init_f() function with your own
271 - preloader_console_init() can be called here in extremis
272 - should set up SDRAM, and anything needed to make the UART work
273 - these is no need to clear BSS, it will be done by crt0.S
274 - must return normally from this function (don't call board_init_r()
277 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
278 this point the stack and global_data are relocated to below
279 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
283 - purpose: main execution, common code
284 - global_data is available
286 - BSS is available, all static/global variables can be used
287 - execution eventually continues to main_loop()
289 Non-SPL-specific notes:
290 - U-Boot is relocated to the top of memory and is now running from
294 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
295 CONFIG_SPL_STACK_R_ADDR points into SDRAM
296 - preloader_console_init() can be called here - typically this is
297 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
298 spl_board_init() function containing this call
299 - loads U-Boot or (in falcon mode) Linux
303 Configuration Options:
304 ----------------------
306 Configuration depends on the combination of board and CPU type; all
307 such information is kept in a configuration file
308 "include/configs/<board_name>.h".
310 Example: For a TQM823L module, all configuration settings are in
311 "include/configs/TQM823L.h".
314 Many of the options are named exactly as the corresponding Linux
315 kernel configuration options. The intention is to make it easier to
316 build a config tool - later.
319 The following options need to be configured:
321 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
323 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
325 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
326 Define exactly one, e.g. CONFIG_ATSTK1002
328 - Marvell Family Member
329 CONFIG_SYS_MVFS - define it if you want to enable
330 multiple fs option at one time
331 for marvell soc family
333 - 8xx CPU Options: (if using an MPC8xx CPU)
334 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
335 get_gclk_freq() cannot work
336 e.g. if there is no 32KHz
337 reference PIT/RTC clock
338 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
341 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342 CONFIG_SYS_8xx_CPUCLK_MIN
343 CONFIG_SYS_8xx_CPUCLK_MAX
344 CONFIG_8xx_CPUCLK_DEFAULT
345 See doc/README.MPC866
347 CONFIG_SYS_MEASURE_CPUCLK
349 Define this to measure the actual CPU clock instead
350 of relying on the correctness of the configured
351 values. Mostly useful for board bringup to make sure
352 the PLL is locked at the intended frequency. Note
353 that this requires a (stable) reference clock (32 kHz
354 RTC clock or CONFIG_SYS_8XX_XIN)
356 CONFIG_SYS_DELAYED_ICACHE
358 Define this option if you want to enable the
359 ICache only when Code runs from RAM.
364 Specifies that the core is a 64-bit PowerPC implementation (implements
365 the "64" category of the Power ISA). This is necessary for ePAPR
366 compliance, among other possible reasons.
368 CONFIG_SYS_FSL_TBCLK_DIV
370 Defines the core time base clock divider ratio compared to the
371 system clock. On most PQ3 devices this is 8, on newer QorIQ
372 devices it can be 16 or 32. The ratio varies from SoC to Soc.
374 CONFIG_SYS_FSL_PCIE_COMPAT
376 Defines the string to utilize when trying to match PCIe device
377 tree nodes for the given platform.
379 CONFIG_SYS_FSL_ERRATUM_A004510
381 Enables a workaround for erratum A004510. If set,
382 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
383 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
385 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
386 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
388 Defines one or two SoC revisions (low 8 bits of SVR)
389 for which the A004510 workaround should be applied.
391 The rest of SVR is either not relevant to the decision
392 of whether the erratum is present (e.g. p2040 versus
393 p2041) or is implied by the build target, which controls
394 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
396 See Freescale App Note 4493 for more information about
399 CONFIG_A003399_NOR_WORKAROUND
400 Enables a workaround for IFC erratum A003399. It is only
401 required during NOR boot.
403 CONFIG_A008044_WORKAROUND
404 Enables a workaround for T1040/T1042 erratum A008044. It is only
405 required during NAND boot and valid for Rev 1.0 SoC revision
407 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
409 This is the value to write into CCSR offset 0x18600
410 according to the A004510 workaround.
412 CONFIG_SYS_FSL_DSP_DDR_ADDR
413 This value denotes start offset of DDR memory which is
414 connected exclusively to the DSP cores.
416 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
417 This value denotes start offset of M2 memory
418 which is directly connected to the DSP core.
420 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
421 This value denotes start offset of M3 memory which is directly
422 connected to the DSP core.
424 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
425 This value denotes start offset of DSP CCSR space.
427 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
428 Single Source Clock is clocking mode present in some of FSL SoC's.
429 In this mode, a single differential clock is used to supply
430 clocks to the sysclock, ddrclock and usbclock.
432 CONFIG_SYS_CPC_REINIT_F
433 This CONFIG is defined when the CPC is configured as SRAM at the
434 time of U-Boot entry and is required to be re-initialized.
437 Indicates this SoC supports deep sleep feature. If deep sleep is
438 supported, core will start to execute uboot when wakes up.
440 - Generic CPU options:
441 CONFIG_SYS_GENERIC_GLOBAL_DATA
442 Defines global data is initialized in generic board board_init_f().
443 If this macro is defined, global data is created and cleared in
444 generic board board_init_f(). Without this macro, architecture/board
445 should initialize global data before calling board_init_f().
447 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
449 Defines the endianess of the CPU. Implementation of those
450 values is arch specific.
453 Freescale DDR driver in use. This type of DDR controller is
454 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
457 CONFIG_SYS_FSL_DDR_ADDR
458 Freescale DDR memory-mapped register base.
460 CONFIG_SYS_FSL_DDR_EMU
461 Specify emulator support for DDR. Some DDR features such as
462 deskew training are not available.
464 CONFIG_SYS_FSL_DDRC_GEN1
465 Freescale DDR1 controller.
467 CONFIG_SYS_FSL_DDRC_GEN2
468 Freescale DDR2 controller.
470 CONFIG_SYS_FSL_DDRC_GEN3
471 Freescale DDR3 controller.
473 CONFIG_SYS_FSL_DDRC_GEN4
474 Freescale DDR4 controller.
476 CONFIG_SYS_FSL_DDRC_ARM_GEN3
477 Freescale DDR3 controller for ARM-based SoCs.
480 Board config to use DDR1. It can be enabled for SoCs with
481 Freescale DDR1 or DDR2 controllers, depending on the board
485 Board config to use DDR2. It can be enabled for SoCs with
486 Freescale DDR2 or DDR3 controllers, depending on the board
490 Board config to use DDR3. It can be enabled for SoCs with
491 Freescale DDR3 or DDR3L controllers.
494 Board config to use DDR3L. It can be enabled for SoCs with
498 Board config to use DDR4. It can be enabled for SoCs with
501 CONFIG_SYS_FSL_IFC_BE
502 Defines the IFC controller register space as Big Endian
504 CONFIG_SYS_FSL_IFC_LE
505 Defines the IFC controller register space as Little Endian
507 CONFIG_SYS_FSL_IFC_CLK_DIV
508 Defines divider of platform clock(clock input to IFC controller).
510 CONFIG_SYS_FSL_LBC_CLK_DIV
511 Defines divider of platform clock(clock input to eLBC controller).
513 CONFIG_SYS_FSL_PBL_PBI
514 It enables addition of RCW (Power on reset configuration) in built image.
515 Please refer doc/README.pblimage for more details
517 CONFIG_SYS_FSL_PBL_RCW
518 It adds PBI(pre-boot instructions) commands in u-boot build image.
519 PBI commands can be used to configure SoC before it starts the execution.
520 Please refer doc/README.pblimage for more details
523 It adds a target to create boot binary having SPL binary in PBI format
524 concatenated with u-boot binary.
526 CONFIG_SYS_FSL_DDR_BE
527 Defines the DDR controller register space as Big Endian
529 CONFIG_SYS_FSL_DDR_LE
530 Defines the DDR controller register space as Little Endian
532 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
533 Physical address from the view of DDR controllers. It is the
534 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
535 it could be different for ARM SoCs.
537 CONFIG_SYS_FSL_DDR_INTLV_256B
538 DDR controller interleaving on 256-byte. This is a special
539 interleaving mode, handled by Dickens for Freescale layerscape
542 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
543 Number of controllers used as main memory.
545 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
546 Number of controllers used for other than main memory.
548 CONFIG_SYS_FSL_HAS_DP_DDR
549 Defines the SoC has DP-DDR used for DPAA.
551 CONFIG_SYS_FSL_SEC_BE
552 Defines the SEC controller register space as Big Endian
554 CONFIG_SYS_FSL_SEC_LE
555 Defines the SEC controller register space as Little Endian
558 CONFIG_SYS_INIT_SP_OFFSET
560 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
561 pointer. This is needed for the temporary stack before
564 CONFIG_SYS_MIPS_CACHE_MODE
566 Cache operation mode for the MIPS CPU.
567 See also arch/mips/include/asm/mipsregs.h.
569 CONF_CM_CACHABLE_NO_WA
572 CONF_CM_CACHABLE_NONCOHERENT
576 CONF_CM_CACHABLE_ACCELERATED
578 CONFIG_SYS_XWAY_EBU_BOOTCFG
580 Special option for Lantiq XWAY SoCs for booting from NOR flash.
581 See also arch/mips/cpu/mips32/start.S.
583 CONFIG_XWAY_SWAP_BYTES
585 Enable compilation of tools/xway-swap-bytes needed for Lantiq
586 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
587 be swapped if a flash programmer is used.
590 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
592 Select high exception vectors of the ARM core, e.g., do not
593 clear the V bit of the c1 register of CP15.
596 Generic timer clock source frequency.
598 COUNTER_FREQUENCY_REAL
599 Generic timer clock source frequency if the real clock is
600 different from COUNTER_FREQUENCY, and can only be determined
604 CONFIG_TEGRA_SUPPORT_NON_SECURE
606 Support executing U-Boot in non-secure (NS) mode. Certain
607 impossible actions will be skipped if the CPU is in NS mode,
608 such as ARM architectural timer initialization.
610 - Linux Kernel Interface:
613 U-Boot stores all clock information in Hz
614 internally. For binary compatibility with older Linux
615 kernels (which expect the clocks passed in the
616 bd_info data to be in MHz) the environment variable
617 "clocks_in_mhz" can be defined so that U-Boot
618 converts clock data to MHZ before passing it to the
620 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
621 "clocks_in_mhz=1" is automatically included in the
624 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
626 When transferring memsize parameter to Linux, some versions
627 expect it to be in bytes, others in MB.
628 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
632 New kernel versions are expecting firmware settings to be
633 passed using flattened device trees (based on open firmware
637 * New libfdt-based support
638 * Adds the "fdt" command
639 * The bootm command automatically updates the fdt
641 OF_CPU - The proper name of the cpus node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_SOC - The proper name of the soc node (only required for
644 MPC512X and MPC5xxx based boards).
645 OF_TBCLK - The timebase frequency.
646 OF_STDOUT_PATH - The path to the console device
648 boards with QUICC Engines require OF_QE to set UCC MAC
651 CONFIG_OF_BOARD_SETUP
653 Board code has addition modification that it wants to make
654 to the flat device tree before handing it off to the kernel
656 CONFIG_OF_SYSTEM_SETUP
658 Other code has addition modification that it wants to make
659 to the flat device tree before handing it off to the kernel.
660 This causes ft_system_setup() to be called before booting
665 U-Boot can detect if an IDE device is present or not.
666 If not, and this new config option is activated, U-Boot
667 removes the ATA node from the DTS before booting Linux,
668 so the Linux IDE driver does not probe the device and
669 crash. This is needed for buggy hardware (uc101) where
670 no pull down resistor is connected to the signal IDE5V_DD7.
672 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
674 This setting is mandatory for all boards that have only one
675 machine type and must be used to specify the machine type
676 number as it appears in the ARM machine registry
677 (see http://www.arm.linux.org.uk/developer/machines/).
678 Only boards that have multiple machine types supported
679 in a single configuration file and the machine type is
680 runtime discoverable, do not have to use this setting.
682 - vxWorks boot parameters:
684 bootvx constructs a valid bootline using the following
685 environments variables: bootdev, bootfile, ipaddr, netmask,
686 serverip, gatewayip, hostname, othbootargs.
687 It loads the vxWorks image pointed bootfile.
689 Note: If a "bootargs" environment is defined, it will overwride
690 the defaults discussed just above.
692 - Cache Configuration:
693 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
694 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
695 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
697 - Cache Configuration for ARM:
698 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
700 CONFIG_SYS_PL310_BASE - Physical base address of PL310
701 controller register space
706 Define this if you want support for Amba PrimeCell PL010 UARTs.
710 Define this if you want support for Amba PrimeCell PL011 UARTs.
714 If you have Amba PrimeCell PL011 UARTs, set this variable to
715 the clock speed of the UARTs.
719 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
720 define this to a list of base addresses for each (supported)
721 port. See e.g. include/configs/versatile.h
723 CONFIG_SERIAL_HW_FLOW_CONTROL
725 Define this variable to enable hw flow control in serial driver.
726 Current user of this option is drivers/serial/nsl16550.c driver
729 Depending on board, define exactly one serial port
730 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
731 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
732 console by defining CONFIG_8xx_CONS_NONE
734 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
735 port routines must be defined elsewhere
736 (i.e. serial_init(), serial_getc(), ...)
739 CONFIG_BAUDRATE - in bps
740 Select one of the baudrates listed in
741 CONFIG_SYS_BAUDRATE_TABLE, see below.
742 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
744 - Console Rx buffer length
745 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
746 the maximum receive buffer length for the SMC.
747 This option is actual only for 82xx and 8xx possible.
748 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
749 must be defined, to setup the maximum idle timeout for
754 Only needed when CONFIG_BOOTDELAY is enabled;
755 define a command string that is automatically executed
756 when no character is read on the console interface
757 within "Boot Delay" after reset.
760 This can be used to pass arguments to the bootm
761 command. The value of CONFIG_BOOTARGS goes into the
762 environment value "bootargs".
764 CONFIG_RAMBOOT and CONFIG_NFSBOOT
765 The value of these goes into the environment as
766 "ramboot" and "nfsboot" respectively, and can be used
767 as a convenience, when switching between booting from
771 CONFIG_BOOTCOUNT_LIMIT
772 Implements a mechanism for detecting a repeating reboot
774 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
777 If no softreset save registers are found on the hardware
778 "bootcount" is stored in the environment. To prevent a
779 saveenv on all reboots, the environment variable
780 "upgrade_available" is used. If "upgrade_available" is
781 0, "bootcount" is always 0, if "upgrade_available" is
782 1 "bootcount" is incremented in the environment.
783 So the Userspace Applikation must set the "upgrade_available"
784 and "bootcount" variable to 0, if a boot was successfully.
789 When this option is #defined, the existence of the
790 environment variable "preboot" will be checked
791 immediately before starting the CONFIG_BOOTDELAY
792 countdown and/or running the auto-boot command resp.
793 entering interactive mode.
795 This feature is especially useful when "preboot" is
796 automatically generated or modified. For an example
797 see the LWMON board specific code: here "preboot" is
798 modified when the user holds down a certain
799 combination of keys on the (special) keyboard when
802 - Serial Download Echo Mode:
804 If defined to 1, all characters received during a
805 serial download (using the "loads" command) are
806 echoed back. This might be needed by some terminal
807 emulations (like "cu"), but may as well just take
808 time on others. This setting #define's the initial
809 value of the "loads_echo" environment variable.
811 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
813 Select one of the baudrates listed in
814 CONFIG_SYS_BAUDRATE_TABLE, see below.
817 Monitor commands can be included or excluded
818 from the build by using the #include files
819 <config_cmd_all.h> and #undef'ing unwanted
820 commands, or adding #define's for wanted commands.
822 The default command configuration includes all commands
823 except those marked below with a "*".
825 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
826 CONFIG_CMD_ASKENV * ask for env variable
827 CONFIG_CMD_BDI bdinfo
828 CONFIG_CMD_BEDBUG * Include BedBug Debugger
829 CONFIG_CMD_BMP * BMP support
830 CONFIG_CMD_BSP * Board specific commands
831 CONFIG_CMD_BOOTD bootd
832 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
833 CONFIG_CMD_CACHE * icache, dcache
834 CONFIG_CMD_CLK * clock command support
835 CONFIG_CMD_CONSOLE coninfo
836 CONFIG_CMD_CRC32 * crc32
837 CONFIG_CMD_DATE * support for RTC, date/time...
838 CONFIG_CMD_DHCP * DHCP support
839 CONFIG_CMD_DIAG * Diagnostics
840 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
841 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
842 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
843 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
844 CONFIG_CMD_DTT * Digital Therm and Thermostat
845 CONFIG_CMD_ECHO echo arguments
846 CONFIG_CMD_EDITENV edit env variable
847 CONFIG_CMD_EEPROM * EEPROM read/write support
848 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
849 CONFIG_CMD_ELF * bootelf, bootvx
850 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
851 CONFIG_CMD_ENV_FLAGS * display details about env flags
852 CONFIG_CMD_ENV_EXISTS * check existence of env variable
853 CONFIG_CMD_EXPORTENV * export the environment
854 CONFIG_CMD_EXT2 * ext2 command support
855 CONFIG_CMD_EXT4 * ext4 command support
856 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
857 that work for multiple fs types
858 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
859 CONFIG_CMD_SAVEENV saveenv
860 CONFIG_CMD_FDC * Floppy Disk Support
861 CONFIG_CMD_FAT * FAT command support
862 CONFIG_CMD_FLASH flinfo, erase, protect
863 CONFIG_CMD_FPGA FPGA device initialization support
864 CONFIG_CMD_FUSE * Device fuse support
865 CONFIG_CMD_GETTIME * Get time since boot
866 CONFIG_CMD_GO * the 'go' command (exec code)
867 CONFIG_CMD_GREPENV * search environment
868 CONFIG_CMD_HASH * calculate hash / digest
869 CONFIG_CMD_I2C * I2C serial bus support
870 CONFIG_CMD_IDE * IDE harddisk support
871 CONFIG_CMD_IMI iminfo
872 CONFIG_CMD_IMLS List all images found in NOR flash
873 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
874 CONFIG_CMD_IMMAP * IMMR dump support
875 CONFIG_CMD_IOTRACE * I/O tracing for debugging
876 CONFIG_CMD_IMPORTENV * import an environment
877 CONFIG_CMD_INI * import data from an ini file into the env
878 CONFIG_CMD_IRQ * irqinfo
879 CONFIG_CMD_ITEST Integer/string test of 2 values
880 CONFIG_CMD_JFFS2 * JFFS2 Support
881 CONFIG_CMD_KGDB * kgdb
882 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
883 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
885 CONFIG_CMD_LOADB loadb
886 CONFIG_CMD_LOADS loads
887 CONFIG_CMD_MD5SUM * print md5 message digest
888 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
889 CONFIG_CMD_MEMINFO * Display detailed memory information
890 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
892 CONFIG_CMD_MEMTEST * mtest
893 CONFIG_CMD_MISC Misc functions like sleep etc
894 CONFIG_CMD_MMC * MMC memory mapped support
895 CONFIG_CMD_MII * MII utility commands
896 CONFIG_CMD_MTDPARTS * MTD partition support
897 CONFIG_CMD_NAND * NAND support
898 CONFIG_CMD_NET bootp, tftpboot, rarpboot
899 CONFIG_CMD_NFS NFS support
900 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
901 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
902 CONFIG_CMD_PCI * pciinfo
903 CONFIG_CMD_PCMCIA * PCMCIA support
904 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
906 CONFIG_CMD_PORTIO * Port I/O
907 CONFIG_CMD_READ * Read raw data from partition
908 CONFIG_CMD_REGINFO * Register dump
909 CONFIG_CMD_RUN run command in env variable
910 CONFIG_CMD_SANDBOX * sb command to access sandbox features
911 CONFIG_CMD_SAVES * save S record dump
912 CONFIG_SCSI * SCSI Support
913 CONFIG_CMD_SDRAM * print SDRAM configuration information
914 (requires CONFIG_CMD_I2C)
915 CONFIG_CMD_SETGETDCR Support for DCR Register access
917 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
918 CONFIG_CMD_SHA1SUM * print sha1 memory digest
919 (requires CONFIG_CMD_MEMORY)
920 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
921 CONFIG_CMD_SOURCE "source" command Support
922 CONFIG_CMD_SPI * SPI serial bus support
923 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
924 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
925 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
926 CONFIG_CMD_TIMER * access to the system tick timer
927 CONFIG_CMD_USB * USB support
928 CONFIG_CMD_CDP * Cisco Discover Protocol support
929 CONFIG_CMD_MFSL * Microblaze FSL support
930 CONFIG_CMD_XIMG Load part of Multi Image
931 CONFIG_CMD_UUID * Generate random UUID or GUID string
933 EXAMPLE: If you want all functions except of network
934 support you can write:
936 #include "config_cmd_all.h"
937 #undef CONFIG_CMD_NET
940 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
942 Note: Don't enable the "icache" and "dcache" commands
943 (configuration option CONFIG_CMD_CACHE) unless you know
944 what you (and your U-Boot users) are doing. Data
945 cache cannot be enabled on systems like the 8xx or
946 8260 (where accesses to the IMMR region must be
947 uncached), and it cannot be disabled on all other
948 systems where we (mis-) use the data cache to hold an
949 initial stack and some data.
952 XXX - this list needs to get updated!
954 - Removal of commands
955 If no commands are needed to boot, you can disable
956 CONFIG_CMDLINE to remove them. In this case, the command line
957 will not be available, and when U-Boot wants to execute the
958 boot command (on start-up) it will call board_run_command()
959 instead. This can reduce image size significantly for very
960 simple boot procedures.
962 - Regular expression support:
964 If this variable is defined, U-Boot is linked against
965 the SLRE (Super Light Regular Expression) library,
966 which adds regex support to some commands, as for
967 example "env grep" and "setexpr".
971 If this variable is defined, U-Boot will use a device tree
972 to configure its devices, instead of relying on statically
973 compiled #defines in the board file. This option is
974 experimental and only available on a few boards. The device
975 tree is available in the global data as gd->fdt_blob.
977 U-Boot needs to get its device tree from somewhere. This can
978 be done using one of the two options below:
981 If this variable is defined, U-Boot will embed a device tree
982 binary in its image. This device tree file should be in the
983 board directory and called <soc>-<board>.dts. The binary file
984 is then picked up in board_init_f() and made available through
985 the global data structure as gd->blob.
988 If this variable is defined, U-Boot will build a device tree
989 binary. It will be called u-boot.dtb. Architecture-specific
990 code will locate it at run-time. Generally this works by:
992 cat u-boot.bin u-boot.dtb >image.bin
994 and in fact, U-Boot does this for you, creating a file called
995 u-boot-dtb.bin which is useful in the common case. You can
996 still use the individual files if you need something more
1001 If this variable is defined, it enables watchdog
1002 support for the SoC. There must be support in the SoC
1003 specific code for a watchdog. For the 8xx and 8260
1004 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1005 register. When supported for a specific SoC is
1006 available, then no further board specific code should
1007 be needed to use it.
1010 When using a watchdog circuitry external to the used
1011 SoC, then define this variable and provide board
1012 specific code for the "hw_watchdog_reset" function.
1014 CONFIG_AT91_HW_WDT_TIMEOUT
1015 specify the timeout in seconds. default 2 seconds.
1018 CONFIG_VERSION_VARIABLE
1019 If this variable is defined, an environment variable
1020 named "ver" is created by U-Boot showing the U-Boot
1021 version as printed by the "version" command.
1022 Any change to this variable will be reverted at the
1027 When CONFIG_CMD_DATE is selected, the type of the RTC
1028 has to be selected, too. Define exactly one of the
1031 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1032 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1033 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1034 CONFIG_RTC_MC146818 - use MC146818 RTC
1035 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1036 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1037 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1038 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1039 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1040 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1041 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1042 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1043 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1046 Note that if the RTC uses I2C, then the I2C interface
1047 must also be configured. See I2C Support, below.
1050 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1052 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1053 chip-ngpio pairs that tell the PCA953X driver the number of
1054 pins supported by a particular chip.
1056 Note that if the GPIO device uses I2C, then the I2C interface
1057 must also be configured. See I2C Support, below.
1060 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1061 accesses and can checksum them or write a list of them out
1062 to memory. See the 'iotrace' command for details. This is
1063 useful for testing device drivers since it can confirm that
1064 the driver behaves the same way before and after a code
1065 change. Currently this is supported on sandbox and arm. To
1066 add support for your architecture, add '#include <iotrace.h>'
1067 to the bottom of arch/<arch>/include/asm/io.h and test.
1069 Example output from the 'iotrace stats' command is below.
1070 Note that if the trace buffer is exhausted, the checksum will
1071 still continue to operate.
1074 Start: 10000000 (buffer start address)
1075 Size: 00010000 (buffer size)
1076 Offset: 00000120 (current buffer offset)
1077 Output: 10000120 (start + offset)
1078 Count: 00000018 (number of trace records)
1079 CRC32: 9526fb66 (CRC32 of all trace records)
1081 - Timestamp Support:
1083 When CONFIG_TIMESTAMP is selected, the timestamp
1084 (date and time) of an image is printed by image
1085 commands like bootm or iminfo. This option is
1086 automatically enabled when you select CONFIG_CMD_DATE .
1088 - Partition Labels (disklabels) Supported:
1089 Zero or more of the following:
1090 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1091 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1092 Intel architecture, USB sticks, etc.
1093 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1094 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1095 bootloader. Note 2TB partition limit; see
1097 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1099 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1100 CONFIG_SCSI) you must configure support for at
1101 least one non-MTD partition type as well.
1104 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1105 board configurations files but used nowhere!
1107 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1108 be performed by calling the function
1109 ide_set_reset(int reset)
1110 which has to be defined in a board specific file
1115 Set this to enable ATAPI support.
1120 Set this to enable support for disks larger than 137GB
1121 Also look at CONFIG_SYS_64BIT_LBA.
1122 Whithout these , LBA48 support uses 32bit variables and will 'only'
1123 support disks up to 2.1TB.
1125 CONFIG_SYS_64BIT_LBA:
1126 When enabled, makes the IDE subsystem use 64bit sector addresses.
1130 At the moment only there is only support for the
1131 SYM53C8XX SCSI controller; define
1132 CONFIG_SCSI_SYM53C8XX to enable it.
1134 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1135 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1136 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1137 maximum numbers of LUNs, SCSI ID's and target
1139 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1141 The environment variable 'scsidevs' is set to the number of
1142 SCSI devices found during the last scan.
1144 - NETWORK Support (PCI):
1146 Support for Intel 8254x/8257x gigabit chips.
1149 Utility code for direct access to the SPI bus on Intel 8257x.
1150 This does not do anything useful unless you set at least one
1151 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1153 CONFIG_E1000_SPI_GENERIC
1154 Allow generic access to the SPI bus on the Intel 8257x, for
1155 example with the "sspi" command.
1158 Management command for E1000 devices. When used on devices
1159 with SPI support you can reprogram the EEPROM from U-Boot.
1162 Support for Intel 82557/82559/82559ER chips.
1163 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1164 write routine for first time initialisation.
1167 Support for Digital 2114x chips.
1168 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1169 modem chip initialisation (KS8761/QS6611).
1172 Support for National dp83815 chips.
1175 Support for National dp8382[01] gigabit chips.
1177 - NETWORK Support (other):
1179 CONFIG_DRIVER_AT91EMAC
1180 Support for AT91RM9200 EMAC.
1183 Define this to use reduced MII inteface
1185 CONFIG_DRIVER_AT91EMAC_QUIET
1186 If this defined, the driver is quiet.
1187 The driver doen't show link status messages.
1189 CONFIG_CALXEDA_XGMAC
1190 Support for the Calxeda XGMAC device
1193 Support for SMSC's LAN91C96 chips.
1195 CONFIG_LAN91C96_USE_32_BIT
1196 Define this to enable 32 bit addressing
1199 Support for SMSC's LAN91C111 chip
1201 CONFIG_SMC91111_BASE
1202 Define this to hold the physical address
1203 of the device (I/O space)
1205 CONFIG_SMC_USE_32_BIT
1206 Define this if data bus is 32 bits
1208 CONFIG_SMC_USE_IOFUNCS
1209 Define this to use i/o functions instead of macros
1210 (some hardware wont work with macros)
1212 CONFIG_DRIVER_TI_EMAC
1213 Support for davinci emac
1215 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1216 Define this if you have more then 3 PHYs.
1219 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1221 CONFIG_FTGMAC100_EGIGA
1222 Define this to use GE link update with gigabit PHY.
1223 Define this if FTGMAC100 is connected to gigabit PHY.
1224 If your system has 10/100 PHY only, it might not occur
1225 wrong behavior. Because PHY usually return timeout or
1226 useless data when polling gigabit status and gigabit
1227 control registers. This behavior won't affect the
1228 correctnessof 10/100 link speed update.
1231 Support for SMSC's LAN911x and LAN921x chips
1234 Define this to hold the physical address
1235 of the device (I/O space)
1237 CONFIG_SMC911X_32_BIT
1238 Define this if data bus is 32 bits
1240 CONFIG_SMC911X_16_BIT
1241 Define this if data bus is 16 bits. If your processor
1242 automatically converts one 32 bit word to two 16 bit
1243 words you may also try CONFIG_SMC911X_32_BIT.
1246 Support for Renesas on-chip Ethernet controller
1248 CONFIG_SH_ETHER_USE_PORT
1249 Define the number of ports to be used
1251 CONFIG_SH_ETHER_PHY_ADDR
1252 Define the ETH PHY's address
1254 CONFIG_SH_ETHER_CACHE_WRITEBACK
1255 If this option is set, the driver enables cache flush.
1259 Support for PWM module on the imx6.
1263 Support TPM devices.
1265 CONFIG_TPM_TIS_INFINEON
1266 Support for Infineon i2c bus TPM devices. Only one device
1267 per system is supported at this time.
1269 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1270 Define the burst count bytes upper limit
1273 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1275 CONFIG_TPM_ST33ZP24_I2C
1276 Support for STMicroelectronics ST33ZP24 I2C devices.
1277 Requires TPM_ST33ZP24 and I2C.
1279 CONFIG_TPM_ST33ZP24_SPI
1280 Support for STMicroelectronics ST33ZP24 SPI devices.
1281 Requires TPM_ST33ZP24 and SPI.
1283 CONFIG_TPM_ATMEL_TWI
1284 Support for Atmel TWI TPM device. Requires I2C support.
1287 Support for generic parallel port TPM devices. Only one device
1288 per system is supported at this time.
1290 CONFIG_TPM_TIS_BASE_ADDRESS
1291 Base address where the generic TPM device is mapped
1292 to. Contemporary x86 systems usually map it at
1296 Add tpm monitor functions.
1297 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1298 provides monitor access to authorized functions.
1301 Define this to enable the TPM support library which provides
1302 functional interfaces to some TPM commands.
1303 Requires support for a TPM device.
1305 CONFIG_TPM_AUTH_SESSIONS
1306 Define this to enable authorized functions in the TPM library.
1307 Requires CONFIG_TPM and CONFIG_SHA1.
1310 At the moment only the UHCI host controller is
1311 supported (PIP405, MIP405, MPC5200); define
1312 CONFIG_USB_UHCI to enable it.
1313 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1314 and define CONFIG_USB_STORAGE to enable the USB
1317 Supported are USB Keyboards and USB Floppy drives
1319 MPC5200 USB requires additional defines:
1321 for 528 MHz Clock: 0x0001bbbb
1325 for differential drivers: 0x00001000
1326 for single ended drivers: 0x00005000
1327 for differential drivers on PSC3: 0x00000100
1328 for single ended drivers on PSC3: 0x00004100
1329 CONFIG_SYS_USB_EVENT_POLL
1330 May be defined to allow interrupt polling
1331 instead of using asynchronous interrupts
1333 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1334 txfilltuning field in the EHCI controller on reset.
1336 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1337 HW module registers.
1340 Define the below if you wish to use the USB console.
1341 Once firmware is rebuilt from a serial console issue the
1342 command "setenv stdin usbtty; setenv stdout usbtty" and
1343 attach your USB cable. The Unix command "dmesg" should print
1344 it has found a new device. The environment variable usbtty
1345 can be set to gserial or cdc_acm to enable your device to
1346 appear to a USB host as a Linux gserial device or a
1347 Common Device Class Abstract Control Model serial device.
1348 If you select usbtty = gserial you should be able to enumerate
1350 # modprobe usbserial vendor=0xVendorID product=0xProductID
1351 else if using cdc_acm, simply setting the environment
1352 variable usbtty to be cdc_acm should suffice. The following
1353 might be defined in YourBoardName.h
1356 Define this to build a UDC device
1359 Define this to have a tty type of device available to
1360 talk to the UDC device
1363 Define this to enable the high speed support for usb
1364 device and usbtty. If this feature is enabled, a routine
1365 int is_usbd_high_speed(void)
1366 also needs to be defined by the driver to dynamically poll
1367 whether the enumeration has succeded at high speed or full
1370 CONFIG_SYS_CONSOLE_IS_IN_ENV
1371 Define this if you want stdin, stdout &/or stderr to
1375 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1376 Derive USB clock from external clock "blah"
1377 - CONFIG_SYS_USB_EXTC_CLK 0x02
1379 If you have a USB-IF assigned VendorID then you may wish to
1380 define your own vendor specific values either in BoardName.h
1381 or directly in usbd_vendor_info.h. If you don't define
1382 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1383 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1384 should pretend to be a Linux device to it's target host.
1386 CONFIG_USBD_MANUFACTURER
1387 Define this string as the name of your company for
1388 - CONFIG_USBD_MANUFACTURER "my company"
1390 CONFIG_USBD_PRODUCT_NAME
1391 Define this string as the name of your product
1392 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1394 CONFIG_USBD_VENDORID
1395 Define this as your assigned Vendor ID from the USB
1396 Implementors Forum. This *must* be a genuine Vendor ID
1397 to avoid polluting the USB namespace.
1398 - CONFIG_USBD_VENDORID 0xFFFF
1400 CONFIG_USBD_PRODUCTID
1401 Define this as the unique Product ID
1403 - CONFIG_USBD_PRODUCTID 0xFFFF
1405 - ULPI Layer Support:
1406 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1407 the generic ULPI layer. The generic layer accesses the ULPI PHY
1408 via the platform viewport, so you need both the genric layer and
1409 the viewport enabled. Currently only Chipidea/ARC based
1410 viewport is supported.
1411 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1412 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1413 If your ULPI phy needs a different reference clock than the
1414 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1415 the appropriate value in Hz.
1418 The MMC controller on the Intel PXA is supported. To
1419 enable this define CONFIG_MMC. The MMC can be
1420 accessed from the boot prompt by mapping the device
1421 to physical memory similar to flash. Command line is
1422 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1423 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1426 Support for Renesas on-chip MMCIF controller
1428 CONFIG_SH_MMCIF_ADDR
1429 Define the base address of MMCIF registers
1432 Define the clock frequency for MMCIF
1434 CONFIG_SUPPORT_EMMC_BOOT
1435 Enable some additional features of the eMMC boot partitions.
1437 CONFIG_SUPPORT_EMMC_RPMB
1438 Enable the commands for reading, writing and programming the
1439 key for the Replay Protection Memory Block partition in eMMC.
1441 - USB Device Firmware Update (DFU) class support:
1442 CONFIG_USB_FUNCTION_DFU
1443 This enables the USB portion of the DFU USB class
1446 This enables the command "dfu" which is used to have
1447 U-Boot create a DFU class device via USB. This command
1448 requires that the "dfu_alt_info" environment variable be
1449 set and define the alt settings to expose to the host.
1452 This enables support for exposing (e)MMC devices via DFU.
1455 This enables support for exposing NAND devices via DFU.
1458 This enables support for exposing RAM via DFU.
1459 Note: DFU spec refer to non-volatile memory usage, but
1460 allow usages beyond the scope of spec - here RAM usage,
1461 one that would help mostly the developer.
1463 CONFIG_SYS_DFU_DATA_BUF_SIZE
1464 Dfu transfer uses a buffer before writing data to the
1465 raw storage device. Make the size (in bytes) of this buffer
1466 configurable. The size of this buffer is also configurable
1467 through the "dfu_bufsiz" environment variable.
1469 CONFIG_SYS_DFU_MAX_FILE_SIZE
1470 When updating files rather than the raw storage device,
1471 we use a static buffer to copy the file into and then write
1472 the buffer once we've been given the whole file. Define
1473 this to the maximum filesize (in bytes) for the buffer.
1474 Default is 4 MiB if undefined.
1476 DFU_DEFAULT_POLL_TIMEOUT
1477 Poll timeout [ms], is the timeout a device can send to the
1478 host. The host must wait for this timeout before sending
1479 a subsequent DFU_GET_STATUS request to the device.
1481 DFU_MANIFEST_POLL_TIMEOUT
1482 Poll timeout [ms], which the device sends to the host when
1483 entering dfuMANIFEST state. Host waits this timeout, before
1484 sending again an USB request to the device.
1486 - USB Device Android Fastboot support:
1487 CONFIG_USB_FUNCTION_FASTBOOT
1488 This enables the USB part of the fastboot gadget
1491 This enables the command "fastboot" which enables the Android
1492 fastboot mode for the platform's USB device. Fastboot is a USB
1493 protocol for downloading images, flashing and device control
1494 used on Android devices.
1495 See doc/README.android-fastboot for more information.
1497 CONFIG_ANDROID_BOOT_IMAGE
1498 This enables support for booting images which use the Android
1499 image format header.
1501 CONFIG_FASTBOOT_BUF_ADDR
1502 The fastboot protocol requires a large memory buffer for
1503 downloads. Define this to the starting RAM address to use for
1506 CONFIG_FASTBOOT_BUF_SIZE
1507 The fastboot protocol requires a large memory buffer for
1508 downloads. This buffer should be as large as possible for a
1509 platform. Define this to the size available RAM for fastboot.
1511 CONFIG_FASTBOOT_FLASH
1512 The fastboot protocol includes a "flash" command for writing
1513 the downloaded image to a non-volatile storage device. Define
1514 this to enable the "fastboot flash" command.
1516 CONFIG_FASTBOOT_FLASH_MMC_DEV
1517 The fastboot "flash" command requires additional information
1518 regarding the non-volatile storage device. Define this to
1519 the eMMC device that fastboot should use to store the image.
1521 CONFIG_FASTBOOT_GPT_NAME
1522 The fastboot "flash" command supports writing the downloaded
1523 image to the Protective MBR and the Primary GUID Partition
1524 Table. (Additionally, this downloaded image is post-processed
1525 to generate and write the Backup GUID Partition Table.)
1526 This occurs when the specified "partition name" on the
1527 "fastboot flash" command line matches this value.
1528 The default is "gpt" if undefined.
1530 CONFIG_FASTBOOT_MBR_NAME
1531 The fastboot "flash" command supports writing the downloaded
1533 This occurs when the "partition name" specified on the
1534 "fastboot flash" command line matches this value.
1535 If not defined the default value "mbr" is used.
1537 - Journaling Flash filesystem support:
1539 Define these for a default partition on a NAND device
1541 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1542 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1543 Define these for a default partition on a NOR device
1545 - FAT(File Allocation Table) filesystem write function support:
1548 Define this to enable support for saving memory data as a
1549 file in FAT formatted partition.
1551 This will also enable the command "fatwrite" enabling the
1552 user to write files to FAT.
1554 - CBFS (Coreboot Filesystem) support:
1557 Define this to enable support for reading from a Coreboot
1558 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1561 - FAT(File Allocation Table) filesystem cluster size:
1562 CONFIG_FS_FAT_MAX_CLUSTSIZE
1564 Define the max cluster size for fat operations else
1565 a default value of 65536 will be defined.
1568 See Kconfig help for available keyboard drivers.
1572 Define this to enable a custom keyboard support.
1573 This simply calls drv_keyboard_init() which must be
1574 defined in your board-specific files. This option is deprecated
1575 and is only used by novena. For new boards, use driver model
1580 Enable the Freescale DIU video driver. Reference boards for
1581 SOCs that have a DIU should define this macro to enable DIU
1582 support, and should also define these other macros:
1588 CONFIG_VIDEO_SW_CURSOR
1589 CONFIG_VGA_AS_SINGLE_DEVICE
1591 CONFIG_VIDEO_BMP_LOGO
1593 The DIU driver will look for the 'video-mode' environment
1594 variable, and if defined, enable the DIU as a console during
1595 boot. See the documentation file doc/README.video for a
1596 description of this variable.
1598 - LCD Support: CONFIG_LCD
1600 Define this to enable LCD support (for output to LCD
1601 display); also select one of the supported displays
1602 by defining one of these:
1606 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1608 CONFIG_NEC_NL6448AC33:
1610 NEC NL6448AC33-18. Active, color, single scan.
1612 CONFIG_NEC_NL6448BC20
1614 NEC NL6448BC20-08. 6.5", 640x480.
1615 Active, color, single scan.
1617 CONFIG_NEC_NL6448BC33_54
1619 NEC NL6448BC33-54. 10.4", 640x480.
1620 Active, color, single scan.
1624 Sharp 320x240. Active, color, single scan.
1625 It isn't 16x9, and I am not sure what it is.
1627 CONFIG_SHARP_LQ64D341
1629 Sharp LQ64D341 display, 640x480.
1630 Active, color, single scan.
1634 HLD1045 display, 640x480.
1635 Active, color, single scan.
1639 Optrex CBL50840-2 NF-FW 99 22 M5
1641 Hitachi LMG6912RPFC-00T
1645 320x240. Black & white.
1647 Normally display is black on white background; define
1648 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1650 CONFIG_LCD_ALIGNMENT
1652 Normally the LCD is page-aligned (typically 4KB). If this is
1653 defined then the LCD will be aligned to this value instead.
1654 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1655 here, since it is cheaper to change data cache settings on
1656 a per-section basis.
1661 Sometimes, for example if the display is mounted in portrait
1662 mode or even if it's mounted landscape but rotated by 180degree,
1663 we need to rotate our content of the display relative to the
1664 framebuffer, so that user can read the messages which are
1666 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1667 initialized with a given rotation from "vl_rot" out of
1668 "vidinfo_t" which is provided by the board specific code.
1669 The value for vl_rot is coded as following (matching to
1670 fbcon=rotate:<n> linux-kernel commandline):
1671 0 = no rotation respectively 0 degree
1672 1 = 90 degree rotation
1673 2 = 180 degree rotation
1674 3 = 270 degree rotation
1676 If CONFIG_LCD_ROTATION is not defined, the console will be
1677 initialized with 0degree rotation.
1681 Support drawing of RLE8-compressed bitmaps on the LCD.
1685 Enables an 'i2c edid' command which can read EDID
1686 information over I2C from an attached LCD display.
1688 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1690 If this option is set, the environment is checked for
1691 a variable "splashimage". If found, the usual display
1692 of logo, copyright and system information on the LCD
1693 is suppressed and the BMP image at the address
1694 specified in "splashimage" is loaded instead. The
1695 console is redirected to the "nulldev", too. This
1696 allows for a "silent" boot where a splash screen is
1697 loaded very quickly after power-on.
1699 CONFIG_SPLASHIMAGE_GUARD
1701 If this option is set, then U-Boot will prevent the environment
1702 variable "splashimage" from being set to a problematic address
1703 (see doc/README.displaying-bmps).
1704 This option is useful for targets where, due to alignment
1705 restrictions, an improperly aligned BMP image will cause a data
1706 abort. If you think you will not have problems with unaligned
1707 accesses (for example because your toolchain prevents them)
1708 there is no need to set this option.
1710 CONFIG_SPLASH_SCREEN_ALIGN
1712 If this option is set the splash image can be freely positioned
1713 on the screen. Environment variable "splashpos" specifies the
1714 position as "x,y". If a positive number is given it is used as
1715 number of pixel from left/top. If a negative number is given it
1716 is used as number of pixel from right/bottom. You can also
1717 specify 'm' for centering the image.
1720 setenv splashpos m,m
1721 => image at center of screen
1723 setenv splashpos 30,20
1724 => image at x = 30 and y = 20
1726 setenv splashpos -10,m
1727 => vertically centered image
1728 at x = dspWidth - bmpWidth - 9
1730 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1732 If this option is set, additionally to standard BMP
1733 images, gzipped BMP images can be displayed via the
1734 splashscreen support or the bmp command.
1736 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1738 If this option is set, 8-bit RLE compressed BMP images
1739 can be displayed via the splashscreen support or the
1742 - Compression support:
1745 Enabled by default to support gzip compressed images.
1749 If this option is set, support for bzip2 compressed
1750 images is included. If not, only uncompressed and gzip
1751 compressed images are supported.
1753 NOTE: the bzip2 algorithm requires a lot of RAM, so
1754 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1759 If this option is set, support for lzma compressed
1762 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1763 requires an amount of dynamic memory that is given by the
1766 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1768 Where lc and lp stand for, respectively, Literal context bits
1769 and Literal pos bits.
1771 This value is upper-bounded by 14MB in the worst case. Anyway,
1772 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1773 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1774 a very small buffer.
1776 Use the lzmainfo tool to determinate the lc and lp values and
1777 then calculate the amount of needed dynamic memory (ensuring
1778 the appropriate CONFIG_SYS_MALLOC_LEN value).
1782 If this option is set, support for LZO compressed images
1788 The address of PHY on MII bus.
1790 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1792 The clock frequency of the MII bus
1796 If this option is set, support for speed/duplex
1797 detection of gigabit PHY is included.
1799 CONFIG_PHY_RESET_DELAY
1801 Some PHY like Intel LXT971A need extra delay after
1802 reset before any MII register access is possible.
1803 For such PHY, set this option to the usec delay
1804 required. (minimum 300usec for LXT971A)
1806 CONFIG_PHY_CMD_DELAY (ppc4xx)
1808 Some PHY like Intel LXT971A need extra delay after
1809 command issued before MII status register can be read
1814 Define a default value for the IP address to use for
1815 the default Ethernet interface, in case this is not
1816 determined through e.g. bootp.
1817 (Environment variable "ipaddr")
1819 - Server IP address:
1822 Defines a default value for the IP address of a TFTP
1823 server to contact when using the "tftboot" command.
1824 (Environment variable "serverip")
1826 CONFIG_KEEP_SERVERADDR
1828 Keeps the server's MAC address, in the env 'serveraddr'
1829 for passing to bootargs (like Linux's netconsole option)
1831 - Gateway IP address:
1834 Defines a default value for the IP address of the
1835 default router where packets to other networks are
1837 (Environment variable "gatewayip")
1842 Defines a default value for the subnet mask (or
1843 routing prefix) which is used to determine if an IP
1844 address belongs to the local subnet or needs to be
1845 forwarded through a router.
1846 (Environment variable "netmask")
1848 - Multicast TFTP Mode:
1851 Defines whether you want to support multicast TFTP as per
1852 rfc-2090; for example to work with atftp. Lets lots of targets
1853 tftp down the same boot image concurrently. Note: the Ethernet
1854 driver in use must provide a function: mcast() to join/leave a
1857 - BOOTP Recovery Mode:
1858 CONFIG_BOOTP_RANDOM_DELAY
1860 If you have many targets in a network that try to
1861 boot using BOOTP, you may want to avoid that all
1862 systems send out BOOTP requests at precisely the same
1863 moment (which would happen for instance at recovery
1864 from a power failure, when all systems will try to
1865 boot, thus flooding the BOOTP server. Defining
1866 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1867 inserted before sending out BOOTP requests. The
1868 following delays are inserted then:
1870 1st BOOTP request: delay 0 ... 1 sec
1871 2nd BOOTP request: delay 0 ... 2 sec
1872 3rd BOOTP request: delay 0 ... 4 sec
1874 BOOTP requests: delay 0 ... 8 sec
1876 CONFIG_BOOTP_ID_CACHE_SIZE
1878 BOOTP packets are uniquely identified using a 32-bit ID. The
1879 server will copy the ID from client requests to responses and
1880 U-Boot will use this to determine if it is the destination of
1881 an incoming response. Some servers will check that addresses
1882 aren't in use before handing them out (usually using an ARP
1883 ping) and therefore take up to a few hundred milliseconds to
1884 respond. Network congestion may also influence the time it
1885 takes for a response to make it back to the client. If that
1886 time is too long, U-Boot will retransmit requests. In order
1887 to allow earlier responses to still be accepted after these
1888 retransmissions, U-Boot's BOOTP client keeps a small cache of
1889 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1890 cache. The default is to keep IDs for up to four outstanding
1891 requests. Increasing this will allow U-Boot to accept offers
1892 from a BOOTP client in networks with unusually high latency.
1894 - DHCP Advanced Options:
1895 You can fine tune the DHCP functionality by defining
1896 CONFIG_BOOTP_* symbols:
1898 CONFIG_BOOTP_SUBNETMASK
1899 CONFIG_BOOTP_GATEWAY
1900 CONFIG_BOOTP_HOSTNAME
1901 CONFIG_BOOTP_NISDOMAIN
1902 CONFIG_BOOTP_BOOTPATH
1903 CONFIG_BOOTP_BOOTFILESIZE
1906 CONFIG_BOOTP_SEND_HOSTNAME
1907 CONFIG_BOOTP_NTPSERVER
1908 CONFIG_BOOTP_TIMEOFFSET
1909 CONFIG_BOOTP_VENDOREX
1910 CONFIG_BOOTP_MAY_FAIL
1912 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1913 environment variable, not the BOOTP server.
1915 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1916 after the configured retry count, the call will fail
1917 instead of starting over. This can be used to fail over
1918 to Link-local IP address configuration if the DHCP server
1921 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1922 serverip from a DHCP server, it is possible that more
1923 than one DNS serverip is offered to the client.
1924 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1925 serverip will be stored in the additional environment
1926 variable "dnsip2". The first DNS serverip is always
1927 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1930 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1931 to do a dynamic update of a DNS server. To do this, they
1932 need the hostname of the DHCP requester.
1933 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1934 of the "hostname" environment variable is passed as
1935 option 12 to the DHCP server.
1937 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1939 A 32bit value in microseconds for a delay between
1940 receiving a "DHCP Offer" and sending the "DHCP Request".
1941 This fixes a problem with certain DHCP servers that don't
1942 respond 100% of the time to a "DHCP request". E.g. On an
1943 AT91RM9200 processor running at 180MHz, this delay needed
1944 to be *at least* 15,000 usec before a Windows Server 2003
1945 DHCP server would reply 100% of the time. I recommend at
1946 least 50,000 usec to be safe. The alternative is to hope
1947 that one of the retries will be successful but note that
1948 the DHCP timeout and retry process takes a longer than
1951 - Link-local IP address negotiation:
1952 Negotiate with other link-local clients on the local network
1953 for an address that doesn't require explicit configuration.
1954 This is especially useful if a DHCP server cannot be guaranteed
1955 to exist in all environments that the device must operate.
1957 See doc/README.link-local for more information.
1960 CONFIG_CDP_DEVICE_ID
1962 The device id used in CDP trigger frames.
1964 CONFIG_CDP_DEVICE_ID_PREFIX
1966 A two character string which is prefixed to the MAC address
1971 A printf format string which contains the ascii name of
1972 the port. Normally is set to "eth%d" which sets
1973 eth0 for the first Ethernet, eth1 for the second etc.
1975 CONFIG_CDP_CAPABILITIES
1977 A 32bit integer which indicates the device capabilities;
1978 0x00000010 for a normal host which does not forwards.
1982 An ascii string containing the version of the software.
1986 An ascii string containing the name of the platform.
1990 A 32bit integer sent on the trigger.
1992 CONFIG_CDP_POWER_CONSUMPTION
1994 A 16bit integer containing the power consumption of the
1995 device in .1 of milliwatts.
1997 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1999 A byte containing the id of the VLAN.
2001 - Status LED: CONFIG_LED_STATUS
2003 Several configurations allow to display the current
2004 status using a LED. For instance, the LED will blink
2005 fast while running U-Boot code, stop blinking as
2006 soon as a reply to a BOOTP request was received, and
2007 start blinking slow once the Linux kernel is running
2008 (supported by a status LED driver in the Linux
2009 kernel). Defining CONFIG_LED_STATUS enables this
2014 CONFIG_LED_STATUS_GPIO
2015 The status LED can be connected to a GPIO pin.
2016 In such cases, the gpio_led driver can be used as a
2017 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2018 to include the gpio_led driver in the U-Boot binary.
2020 CONFIG_GPIO_LED_INVERTED_TABLE
2021 Some GPIO connected LEDs may have inverted polarity in which
2022 case the GPIO high value corresponds to LED off state and
2023 GPIO low value corresponds to LED on state.
2024 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2025 with a list of GPIO LEDs that have inverted polarity.
2027 - CAN Support: CONFIG_CAN_DRIVER
2029 Defining CONFIG_CAN_DRIVER enables CAN driver support
2030 on those systems that support this (optional)
2031 feature, like the TQM8xxL modules.
2033 - I2C Support: CONFIG_SYS_I2C
2035 This enable the NEW i2c subsystem, and will allow you to use
2036 i2c commands at the u-boot command line (as long as you set
2037 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2038 based realtime clock chips or other i2c devices. See
2039 common/cmd_i2c.c for a description of the command line
2042 ported i2c driver to the new framework:
2043 - drivers/i2c/soft_i2c.c:
2044 - activate first bus with CONFIG_SYS_I2C_SOFT define
2045 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2046 for defining speed and slave address
2047 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2048 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2049 for defining speed and slave address
2050 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2051 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2052 for defining speed and slave address
2053 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2054 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2055 for defining speed and slave address
2057 - drivers/i2c/fsl_i2c.c:
2058 - activate i2c driver with CONFIG_SYS_I2C_FSL
2059 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2060 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2061 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2063 - If your board supports a second fsl i2c bus, define
2064 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2065 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2066 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2069 - drivers/i2c/tegra_i2c.c:
2070 - activate this driver with CONFIG_SYS_I2C_TEGRA
2071 - This driver adds 4 i2c buses with a fix speed from
2072 100000 and the slave addr 0!
2074 - drivers/i2c/ppc4xx_i2c.c
2075 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2076 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2077 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2079 - drivers/i2c/i2c_mxc.c
2080 - activate this driver with CONFIG_SYS_I2C_MXC
2081 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2082 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2083 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2084 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2085 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2086 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2087 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2088 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2089 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2090 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2091 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2092 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2093 If those defines are not set, default value is 100000
2094 for speed, and 0 for slave.
2096 - drivers/i2c/rcar_i2c.c:
2097 - activate this driver with CONFIG_SYS_I2C_RCAR
2098 - This driver adds 4 i2c buses
2100 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2101 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2102 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2103 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2104 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2105 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2106 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2107 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2108 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2110 - drivers/i2c/sh_i2c.c:
2111 - activate this driver with CONFIG_SYS_I2C_SH
2112 - This driver adds from 2 to 5 i2c buses
2114 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2115 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2116 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2117 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2118 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2119 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2120 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2121 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2122 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2123 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2124 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2126 - drivers/i2c/omap24xx_i2c.c
2127 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2128 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2129 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2130 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2131 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2132 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2133 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2134 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2135 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2136 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2137 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2139 - drivers/i2c/zynq_i2c.c
2140 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2141 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2142 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2144 - drivers/i2c/s3c24x0_i2c.c:
2145 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2146 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2147 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2148 with a fix speed from 100000 and the slave addr 0!
2150 - drivers/i2c/ihs_i2c.c
2151 - activate this driver with CONFIG_SYS_I2C_IHS
2152 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2153 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2154 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2155 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2156 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2157 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2158 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2159 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2160 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2161 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2162 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2163 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2164 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2165 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2166 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2167 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2168 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2169 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2170 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2171 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2172 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2176 CONFIG_SYS_NUM_I2C_BUSES
2177 Hold the number of i2c buses you want to use.
2179 CONFIG_SYS_I2C_DIRECT_BUS
2180 define this, if you don't use i2c muxes on your hardware.
2181 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2184 CONFIG_SYS_I2C_MAX_HOPS
2185 define how many muxes are maximal consecutively connected
2186 on one i2c bus. If you not use i2c muxes, omit this
2189 CONFIG_SYS_I2C_BUSES
2190 hold a list of buses you want to use, only used if
2191 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2192 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2193 CONFIG_SYS_NUM_I2C_BUSES = 9:
2195 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2196 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2197 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2198 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2199 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2200 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2201 {1, {I2C_NULL_HOP}}, \
2202 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2203 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2207 bus 0 on adapter 0 without a mux
2208 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2209 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2210 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2211 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2212 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2213 bus 6 on adapter 1 without a mux
2214 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2215 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2217 If you do not have i2c muxes on your board, omit this define.
2219 - Legacy I2C Support: CONFIG_HARD_I2C
2221 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2222 provides the following compelling advantages:
2224 - more than one i2c adapter is usable
2225 - approved multibus support
2226 - better i2c mux support
2228 ** Please consider updating your I2C driver now. **
2230 These enable legacy I2C serial bus commands. Defining
2231 CONFIG_HARD_I2C will include the appropriate I2C driver
2232 for the selected CPU.
2234 This will allow you to use i2c commands at the u-boot
2235 command line (as long as you set CONFIG_CMD_I2C in
2236 CONFIG_COMMANDS) and communicate with i2c based realtime
2237 clock chips. See common/cmd_i2c.c for a description of the
2238 command line interface.
2240 CONFIG_HARD_I2C selects a hardware I2C controller.
2242 There are several other quantities that must also be
2243 defined when you define CONFIG_HARD_I2C.
2245 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2246 to be the frequency (in Hz) at which you wish your i2c bus
2247 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2248 the CPU's i2c node address).
2250 Now, the u-boot i2c code for the mpc8xx
2251 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2252 and so its address should therefore be cleared to 0 (See,
2253 eg, MPC823e User's Manual p.16-473). So, set
2254 CONFIG_SYS_I2C_SLAVE to 0.
2256 CONFIG_SYS_I2C_INIT_MPC5XXX
2258 When a board is reset during an i2c bus transfer
2259 chips might think that the current transfer is still
2260 in progress. Reset the slave devices by sending start
2261 commands until the slave device responds.
2263 That's all that's required for CONFIG_HARD_I2C.
2265 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2266 then the following macros need to be defined (examples are
2267 from include/configs/lwmon.h):
2271 (Optional). Any commands necessary to enable the I2C
2272 controller or configure ports.
2274 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2278 (Only for MPC8260 CPU). The I/O port to use (the code
2279 assumes both bits are on the same port). Valid values
2280 are 0..3 for ports A..D.
2284 The code necessary to make the I2C data line active
2285 (driven). If the data line is open collector, this
2288 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2292 The code necessary to make the I2C data line tri-stated
2293 (inactive). If the data line is open collector, this
2296 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2300 Code that returns true if the I2C data line is high,
2303 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2307 If <bit> is true, sets the I2C data line high. If it
2308 is false, it clears it (low).
2310 eg: #define I2C_SDA(bit) \
2311 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2312 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2316 If <bit> is true, sets the I2C clock line high. If it
2317 is false, it clears it (low).
2319 eg: #define I2C_SCL(bit) \
2320 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2321 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2325 This delay is invoked four times per clock cycle so this
2326 controls the rate of data transfer. The data rate thus
2327 is 1 / (I2C_DELAY * 4). Often defined to be something
2330 #define I2C_DELAY udelay(2)
2332 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2334 If your arch supports the generic GPIO framework (asm/gpio.h),
2335 then you may alternatively define the two GPIOs that are to be
2336 used as SCL / SDA. Any of the previous I2C_xxx macros will
2337 have GPIO-based defaults assigned to them as appropriate.
2339 You should define these to the GPIO value as given directly to
2340 the generic GPIO functions.
2342 CONFIG_SYS_I2C_INIT_BOARD
2344 When a board is reset during an i2c bus transfer
2345 chips might think that the current transfer is still
2346 in progress. On some boards it is possible to access
2347 the i2c SCLK line directly, either by using the
2348 processor pin as a GPIO or by having a second pin
2349 connected to the bus. If this option is defined a
2350 custom i2c_init_board() routine in boards/xxx/board.c
2351 is run early in the boot sequence.
2353 CONFIG_SYS_I2C_BOARD_LATE_INIT
2355 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2356 defined a custom i2c_board_late_init() routine in
2357 boards/xxx/board.c is run AFTER the operations in i2c_init()
2358 is completed. This callpoint can be used to unreset i2c bus
2359 using CPU i2c controller register accesses for CPUs whose i2c
2360 controller provide such a method. It is called at the end of
2361 i2c_init() to allow i2c_init operations to setup the i2c bus
2362 controller on the CPU (e.g. setting bus speed & slave address).
2364 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2366 This option enables configuration of bi_iic_fast[] flags
2367 in u-boot bd_info structure based on u-boot environment
2368 variable "i2cfast". (see also i2cfast)
2370 CONFIG_I2C_MULTI_BUS
2372 This option allows the use of multiple I2C buses, each of which
2373 must have a controller. At any point in time, only one bus is
2374 active. To switch to a different bus, use the 'i2c dev' command.
2375 Note that bus numbering is zero-based.
2377 CONFIG_SYS_I2C_NOPROBES
2379 This option specifies a list of I2C devices that will be skipped
2380 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2381 is set, specify a list of bus-device pairs. Otherwise, specify
2382 a 1D array of device addresses
2385 #undef CONFIG_I2C_MULTI_BUS
2386 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2388 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2390 #define CONFIG_I2C_MULTI_BUS
2391 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2393 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2395 CONFIG_SYS_SPD_BUS_NUM
2397 If defined, then this indicates the I2C bus number for DDR SPD.
2398 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2400 CONFIG_SYS_RTC_BUS_NUM
2402 If defined, then this indicates the I2C bus number for the RTC.
2403 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2405 CONFIG_SYS_DTT_BUS_NUM
2407 If defined, then this indicates the I2C bus number for the DTT.
2408 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2410 CONFIG_SYS_I2C_DTT_ADDR:
2412 If defined, specifies the I2C address of the DTT device.
2413 If not defined, then U-Boot uses predefined value for
2414 specified DTT device.
2416 CONFIG_SOFT_I2C_READ_REPEATED_START
2418 defining this will force the i2c_read() function in
2419 the soft_i2c driver to perform an I2C repeated start
2420 between writing the address pointer and reading the
2421 data. If this define is omitted the default behaviour
2422 of doing a stop-start sequence will be used. Most I2C
2423 devices can use either method, but some require one or
2426 - SPI Support: CONFIG_SPI
2428 Enables SPI driver (so far only tested with
2429 SPI EEPROM, also an instance works with Crystal A/D and
2430 D/As on the SACSng board)
2434 Enables the driver for SPI controller on SuperH. Currently
2435 only SH7757 is supported.
2439 Enables a software (bit-bang) SPI driver rather than
2440 using hardware support. This is a general purpose
2441 driver that only requires three general I/O port pins
2442 (two outputs, one input) to function. If this is
2443 defined, the board configuration must define several
2444 SPI configuration items (port pins to use, etc). For
2445 an example, see include/configs/sacsng.h.
2449 Enables a hardware SPI driver for general-purpose reads
2450 and writes. As with CONFIG_SOFT_SPI, the board configuration
2451 must define a list of chip-select function pointers.
2452 Currently supported on some MPC8xxx processors. For an
2453 example, see include/configs/mpc8349emds.h.
2457 Enables the driver for the SPI controllers on i.MX and MXC
2458 SoCs. Currently i.MX31/35/51 are supported.
2460 CONFIG_SYS_SPI_MXC_WAIT
2461 Timeout for waiting until spi transfer completed.
2462 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2464 - FPGA Support: CONFIG_FPGA
2466 Enables FPGA subsystem.
2468 CONFIG_FPGA_<vendor>
2470 Enables support for specific chip vendors.
2473 CONFIG_FPGA_<family>
2475 Enables support for FPGA family.
2476 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2480 Specify the number of FPGA devices to support.
2482 CONFIG_CMD_FPGA_LOADMK
2484 Enable support for fpga loadmk command
2486 CONFIG_CMD_FPGA_LOADP
2488 Enable support for fpga loadp command - load partial bitstream
2490 CONFIG_CMD_FPGA_LOADBP
2492 Enable support for fpga loadbp command - load partial bitstream
2495 CONFIG_SYS_FPGA_PROG_FEEDBACK
2497 Enable printing of hash marks during FPGA configuration.
2499 CONFIG_SYS_FPGA_CHECK_BUSY
2501 Enable checks on FPGA configuration interface busy
2502 status by the configuration function. This option
2503 will require a board or device specific function to
2508 If defined, a function that provides delays in the FPGA
2509 configuration driver.
2511 CONFIG_SYS_FPGA_CHECK_CTRLC
2512 Allow Control-C to interrupt FPGA configuration
2514 CONFIG_SYS_FPGA_CHECK_ERROR
2516 Check for configuration errors during FPGA bitfile
2517 loading. For example, abort during Virtex II
2518 configuration if the INIT_B line goes low (which
2519 indicated a CRC error).
2521 CONFIG_SYS_FPGA_WAIT_INIT
2523 Maximum time to wait for the INIT_B line to de-assert
2524 after PROB_B has been de-asserted during a Virtex II
2525 FPGA configuration sequence. The default time is 500
2528 CONFIG_SYS_FPGA_WAIT_BUSY
2530 Maximum time to wait for BUSY to de-assert during
2531 Virtex II FPGA configuration. The default is 5 ms.
2533 CONFIG_SYS_FPGA_WAIT_CONFIG
2535 Time to wait after FPGA configuration. The default is
2538 - Configuration Management:
2541 Some SoCs need special image types (e.g. U-Boot binary
2542 with a special header) as build targets. By defining
2543 CONFIG_BUILD_TARGET in the SoC / board header, this
2544 special image will be automatically built upon calling
2549 If defined, this string will be added to the U-Boot
2550 version information (U_BOOT_VERSION)
2552 - Vendor Parameter Protection:
2554 U-Boot considers the values of the environment
2555 variables "serial#" (Board Serial Number) and
2556 "ethaddr" (Ethernet Address) to be parameters that
2557 are set once by the board vendor / manufacturer, and
2558 protects these variables from casual modification by
2559 the user. Once set, these variables are read-only,
2560 and write or delete attempts are rejected. You can
2561 change this behaviour:
2563 If CONFIG_ENV_OVERWRITE is #defined in your config
2564 file, the write protection for vendor parameters is
2565 completely disabled. Anybody can change or delete
2568 Alternatively, if you define _both_ an ethaddr in the
2569 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2570 Ethernet address is installed in the environment,
2571 which can be changed exactly ONCE by the user. [The
2572 serial# is unaffected by this, i. e. it remains
2575 The same can be accomplished in a more flexible way
2576 for any variable by configuring the type of access
2577 to allow for those variables in the ".flags" variable
2578 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2583 Define this variable to enable the reservation of
2584 "protected RAM", i. e. RAM which is not overwritten
2585 by U-Boot. Define CONFIG_PRAM to hold the number of
2586 kB you want to reserve for pRAM. You can overwrite
2587 this default value by defining an environment
2588 variable "pram" to the number of kB you want to
2589 reserve. Note that the board info structure will
2590 still show the full amount of RAM. If pRAM is
2591 reserved, a new environment variable "mem" will
2592 automatically be defined to hold the amount of
2593 remaining RAM in a form that can be passed as boot
2594 argument to Linux, for instance like that:
2596 setenv bootargs ... mem=\${mem}
2599 This way you can tell Linux not to use this memory,
2600 either, which results in a memory region that will
2601 not be affected by reboots.
2603 *WARNING* If your board configuration uses automatic
2604 detection of the RAM size, you must make sure that
2605 this memory test is non-destructive. So far, the
2606 following board configurations are known to be
2609 IVMS8, IVML24, SPD8xx, TQM8xxL,
2610 HERMES, IP860, RPXlite, LWMON,
2613 - Access to physical memory region (> 4GB)
2614 Some basic support is provided for operations on memory not
2615 normally accessible to U-Boot - e.g. some architectures
2616 support access to more than 4GB of memory on 32-bit
2617 machines using physical address extension or similar.
2618 Define CONFIG_PHYSMEM to access this basic support, which
2619 currently only supports clearing the memory.
2624 Define this variable to stop the system in case of a
2625 fatal error, so that you have to reset it manually.
2626 This is probably NOT a good idea for an embedded
2627 system where you want the system to reboot
2628 automatically as fast as possible, but it may be
2629 useful during development since you can try to debug
2630 the conditions that lead to the situation.
2632 CONFIG_NET_RETRY_COUNT
2634 This variable defines the number of retries for
2635 network operations like ARP, RARP, TFTP, or BOOTP
2636 before giving up the operation. If not defined, a
2637 default value of 5 is used.
2641 Timeout waiting for an ARP reply in milliseconds.
2645 Timeout in milliseconds used in NFS protocol.
2646 If you encounter "ERROR: Cannot umount" in nfs command,
2647 try longer timeout such as
2648 #define CONFIG_NFS_TIMEOUT 10000UL
2650 - Command Interpreter:
2651 CONFIG_AUTO_COMPLETE
2653 Enable auto completion of commands using TAB.
2655 CONFIG_SYS_PROMPT_HUSH_PS2
2657 This defines the secondary prompt string, which is
2658 printed when the command interpreter needs more input
2659 to complete a command. Usually "> ".
2663 In the current implementation, the local variables
2664 space and global environment variables space are
2665 separated. Local variables are those you define by
2666 simply typing `name=value'. To access a local
2667 variable later on, you have write `$name' or
2668 `${name}'; to execute the contents of a variable
2669 directly type `$name' at the command prompt.
2671 Global environment variables are those you use
2672 setenv/printenv to work with. To run a command stored
2673 in such a variable, you need to use the run command,
2674 and you must not use the '$' sign to access them.
2676 To store commands and special characters in a
2677 variable, please use double quotation marks
2678 surrounding the whole text of the variable, instead
2679 of the backslashes before semicolons and special
2682 - Command Line Editing and History:
2683 CONFIG_CMDLINE_EDITING
2685 Enable editing and History functions for interactive
2686 command line input operations
2688 - Command Line PS1/PS2 support:
2689 CONFIG_CMDLINE_PS_SUPPORT
2691 Enable support for changing the command prompt string
2692 at run-time. Only static string is supported so far.
2693 The string is obtained from environment variables PS1
2696 - Default Environment:
2697 CONFIG_EXTRA_ENV_SETTINGS
2699 Define this to contain any number of null terminated
2700 strings (variable = value pairs) that will be part of
2701 the default environment compiled into the boot image.
2703 For example, place something like this in your
2704 board's config file:
2706 #define CONFIG_EXTRA_ENV_SETTINGS \
2710 Warning: This method is based on knowledge about the
2711 internal format how the environment is stored by the
2712 U-Boot code. This is NOT an official, exported
2713 interface! Although it is unlikely that this format
2714 will change soon, there is no guarantee either.
2715 You better know what you are doing here.
2717 Note: overly (ab)use of the default environment is
2718 discouraged. Make sure to check other ways to preset
2719 the environment like the "source" command or the
2722 CONFIG_ENV_VARS_UBOOT_CONFIG
2724 Define this in order to add variables describing the
2725 U-Boot build configuration to the default environment.
2726 These will be named arch, cpu, board, vendor, and soc.
2728 Enabling this option will cause the following to be defined:
2736 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2738 Define this in order to add variables describing certain
2739 run-time determined information about the hardware to the
2740 environment. These will be named board_name, board_rev.
2742 CONFIG_DELAY_ENVIRONMENT
2744 Normally the environment is loaded when the board is
2745 initialised so that it is available to U-Boot. This inhibits
2746 that so that the environment is not available until
2747 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2748 this is instead controlled by the value of
2749 /config/load-environment.
2751 - DataFlash Support:
2752 CONFIG_HAS_DATAFLASH
2754 Defining this option enables DataFlash features and
2755 allows to read/write in Dataflash via the standard
2758 - Serial Flash support
2761 Defining this option enables SPI flash commands
2762 'sf probe/read/write/erase/update'.
2764 Usage requires an initial 'probe' to define the serial
2765 flash parameters, followed by read/write/erase/update
2768 The following defaults may be provided by the platform
2769 to handle the common case when only a single serial
2770 flash is present on the system.
2772 CONFIG_SF_DEFAULT_BUS Bus identifier
2773 CONFIG_SF_DEFAULT_CS Chip-select
2774 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2775 CONFIG_SF_DEFAULT_SPEED in Hz
2779 Define this option to include a destructive SPI flash
2782 CONFIG_SF_DUAL_FLASH Dual flash memories
2784 Define this option to use dual flash support where two flash
2785 memories can be connected with a given cs line.
2786 Currently Xilinx Zynq qspi supports these type of connections.
2788 - SystemACE Support:
2791 Adding this option adds support for Xilinx SystemACE
2792 chips attached via some sort of local bus. The address
2793 of the chip must also be defined in the
2794 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2796 #define CONFIG_SYSTEMACE
2797 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2799 When SystemACE support is added, the "ace" device type
2800 becomes available to the fat commands, i.e. fatls.
2802 - TFTP Fixed UDP Port:
2805 If this is defined, the environment variable tftpsrcp
2806 is used to supply the TFTP UDP source port value.
2807 If tftpsrcp isn't defined, the normal pseudo-random port
2808 number generator is used.
2810 Also, the environment variable tftpdstp is used to supply
2811 the TFTP UDP destination port value. If tftpdstp isn't
2812 defined, the normal port 69 is used.
2814 The purpose for tftpsrcp is to allow a TFTP server to
2815 blindly start the TFTP transfer using the pre-configured
2816 target IP address and UDP port. This has the effect of
2817 "punching through" the (Windows XP) firewall, allowing
2818 the remainder of the TFTP transfer to proceed normally.
2819 A better solution is to properly configure the firewall,
2820 but sometimes that is not allowed.
2825 This enables a generic 'hash' command which can produce
2826 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2830 Enable the hash verify command (hash -v). This adds to code
2833 CONFIG_SHA1 - This option enables support of hashing using SHA1
2834 algorithm. The hash is calculated in software.
2835 CONFIG_SHA256 - This option enables support of hashing using
2836 SHA256 algorithm. The hash is calculated in software.
2837 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2838 for SHA1/SHA256 hashing.
2839 This affects the 'hash' command and also the
2840 hash_lookup_algo() function.
2841 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2842 hardware-acceleration for SHA1/SHA256 progressive hashing.
2843 Data can be streamed in a block at a time and the hashing
2844 is performed in hardware.
2846 Note: There is also a sha1sum command, which should perhaps
2847 be deprecated in favour of 'hash sha1'.
2849 - Freescale i.MX specific commands:
2850 CONFIG_CMD_HDMIDETECT
2851 This enables 'hdmidet' command which returns true if an
2852 HDMI monitor is detected. This command is i.MX 6 specific.
2855 This enables the 'bmode' (bootmode) command for forcing
2856 a boot from specific media.
2858 This is useful for forcing the ROM's usb downloader to
2859 activate upon a watchdog reset which is nice when iterating
2860 on U-Boot. Using the reset button or running bmode normal
2861 will set it back to normal. This command currently
2862 supports i.MX53 and i.MX6.
2864 - bootcount support:
2865 CONFIG_BOOTCOUNT_LIMIT
2867 This enables the bootcounter support, see:
2868 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2871 enable special bootcounter support on at91sam9xe based boards.
2873 enable special bootcounter support on blackfin based boards.
2875 enable special bootcounter support on da850 based boards.
2876 CONFIG_BOOTCOUNT_RAM
2877 enable support for the bootcounter in RAM
2878 CONFIG_BOOTCOUNT_I2C
2879 enable support for the bootcounter on an i2c (like RTC) device.
2880 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2881 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2883 CONFIG_BOOTCOUNT_ALEN = address len
2885 - Show boot progress:
2886 CONFIG_SHOW_BOOT_PROGRESS
2888 Defining this option allows to add some board-
2889 specific code (calling a user-provided function
2890 "show_boot_progress(int)") that enables you to show
2891 the system's boot progress on some display (for
2892 example, some LED's) on your board. At the moment,
2893 the following checkpoints are implemented:
2896 Legacy uImage format:
2899 1 common/cmd_bootm.c before attempting to boot an image
2900 -1 common/cmd_bootm.c Image header has bad magic number
2901 2 common/cmd_bootm.c Image header has correct magic number
2902 -2 common/cmd_bootm.c Image header has bad checksum
2903 3 common/cmd_bootm.c Image header has correct checksum
2904 -3 common/cmd_bootm.c Image data has bad checksum
2905 4 common/cmd_bootm.c Image data has correct checksum
2906 -4 common/cmd_bootm.c Image is for unsupported architecture
2907 5 common/cmd_bootm.c Architecture check OK
2908 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2909 6 common/cmd_bootm.c Image Type check OK
2910 -6 common/cmd_bootm.c gunzip uncompression error
2911 -7 common/cmd_bootm.c Unimplemented compression type
2912 7 common/cmd_bootm.c Uncompression OK
2913 8 common/cmd_bootm.c No uncompress/copy overwrite error
2914 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2916 9 common/image.c Start initial ramdisk verification
2917 -10 common/image.c Ramdisk header has bad magic number
2918 -11 common/image.c Ramdisk header has bad checksum
2919 10 common/image.c Ramdisk header is OK
2920 -12 common/image.c Ramdisk data has bad checksum
2921 11 common/image.c Ramdisk data has correct checksum
2922 12 common/image.c Ramdisk verification complete, start loading
2923 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2924 13 common/image.c Start multifile image verification
2925 14 common/image.c No initial ramdisk, no multifile, continue.
2927 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2929 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2930 -31 post/post.c POST test failed, detected by post_output_backlog()
2931 -32 post/post.c POST test failed, detected by post_run_single()
2933 34 common/cmd_doc.c before loading a Image from a DOC device
2934 -35 common/cmd_doc.c Bad usage of "doc" command
2935 35 common/cmd_doc.c correct usage of "doc" command
2936 -36 common/cmd_doc.c No boot device
2937 36 common/cmd_doc.c correct boot device
2938 -37 common/cmd_doc.c Unknown Chip ID on boot device
2939 37 common/cmd_doc.c correct chip ID found, device available
2940 -38 common/cmd_doc.c Read Error on boot device
2941 38 common/cmd_doc.c reading Image header from DOC device OK
2942 -39 common/cmd_doc.c Image header has bad magic number
2943 39 common/cmd_doc.c Image header has correct magic number
2944 -40 common/cmd_doc.c Error reading Image from DOC device
2945 40 common/cmd_doc.c Image header has correct magic number
2946 41 common/cmd_ide.c before loading a Image from a IDE device
2947 -42 common/cmd_ide.c Bad usage of "ide" command
2948 42 common/cmd_ide.c correct usage of "ide" command
2949 -43 common/cmd_ide.c No boot device
2950 43 common/cmd_ide.c boot device found
2951 -44 common/cmd_ide.c Device not available
2952 44 common/cmd_ide.c Device available
2953 -45 common/cmd_ide.c wrong partition selected
2954 45 common/cmd_ide.c partition selected
2955 -46 common/cmd_ide.c Unknown partition table
2956 46 common/cmd_ide.c valid partition table found
2957 -47 common/cmd_ide.c Invalid partition type
2958 47 common/cmd_ide.c correct partition type
2959 -48 common/cmd_ide.c Error reading Image Header on boot device
2960 48 common/cmd_ide.c reading Image Header from IDE device OK
2961 -49 common/cmd_ide.c Image header has bad magic number
2962 49 common/cmd_ide.c Image header has correct magic number
2963 -50 common/cmd_ide.c Image header has bad checksum
2964 50 common/cmd_ide.c Image header has correct checksum
2965 -51 common/cmd_ide.c Error reading Image from IDE device
2966 51 common/cmd_ide.c reading Image from IDE device OK
2967 52 common/cmd_nand.c before loading a Image from a NAND device
2968 -53 common/cmd_nand.c Bad usage of "nand" command
2969 53 common/cmd_nand.c correct usage of "nand" command
2970 -54 common/cmd_nand.c No boot device
2971 54 common/cmd_nand.c boot device found
2972 -55 common/cmd_nand.c Unknown Chip ID on boot device
2973 55 common/cmd_nand.c correct chip ID found, device available
2974 -56 common/cmd_nand.c Error reading Image Header on boot device
2975 56 common/cmd_nand.c reading Image Header from NAND device OK
2976 -57 common/cmd_nand.c Image header has bad magic number
2977 57 common/cmd_nand.c Image header has correct magic number
2978 -58 common/cmd_nand.c Error reading Image from NAND device
2979 58 common/cmd_nand.c reading Image from NAND device OK
2981 -60 common/env_common.c Environment has a bad CRC, using default
2983 64 net/eth.c starting with Ethernet configuration.
2984 -64 net/eth.c no Ethernet found.
2985 65 net/eth.c Ethernet found.
2987 -80 common/cmd_net.c usage wrong
2988 80 common/cmd_net.c before calling net_loop()
2989 -81 common/cmd_net.c some error in net_loop() occurred
2990 81 common/cmd_net.c net_loop() back without error
2991 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2992 82 common/cmd_net.c trying automatic boot
2993 83 common/cmd_net.c running "source" command
2994 -83 common/cmd_net.c some error in automatic boot or "source" command
2995 84 common/cmd_net.c end without errors
3000 100 common/cmd_bootm.c Kernel FIT Image has correct format
3001 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3002 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3003 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3004 102 common/cmd_bootm.c Kernel unit name specified
3005 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3006 103 common/cmd_bootm.c Found configuration node
3007 104 common/cmd_bootm.c Got kernel subimage node offset
3008 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3009 105 common/cmd_bootm.c Kernel subimage hash verification OK
3010 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3011 106 common/cmd_bootm.c Architecture check OK
3012 -106 common/cmd_bootm.c Kernel subimage has wrong type
3013 107 common/cmd_bootm.c Kernel subimage type OK
3014 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3015 108 common/cmd_bootm.c Got kernel subimage data/size
3016 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3017 -109 common/cmd_bootm.c Can't get kernel subimage type
3018 -110 common/cmd_bootm.c Can't get kernel subimage comp
3019 -111 common/cmd_bootm.c Can't get kernel subimage os
3020 -112 common/cmd_bootm.c Can't get kernel subimage load address
3021 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3023 120 common/image.c Start initial ramdisk verification
3024 -120 common/image.c Ramdisk FIT image has incorrect format
3025 121 common/image.c Ramdisk FIT image has correct format
3026 122 common/image.c No ramdisk subimage unit name, using configuration
3027 -122 common/image.c Can't get configuration for ramdisk subimage
3028 123 common/image.c Ramdisk unit name specified
3029 -124 common/image.c Can't get ramdisk subimage node offset
3030 125 common/image.c Got ramdisk subimage node offset
3031 -125 common/image.c Ramdisk subimage hash verification failed
3032 126 common/image.c Ramdisk subimage hash verification OK
3033 -126 common/image.c Ramdisk subimage for unsupported architecture
3034 127 common/image.c Architecture check OK
3035 -127 common/image.c Can't get ramdisk subimage data/size
3036 128 common/image.c Got ramdisk subimage data/size
3037 129 common/image.c Can't get ramdisk load address
3038 -129 common/image.c Got ramdisk load address
3040 -130 common/cmd_doc.c Incorrect FIT image format
3041 131 common/cmd_doc.c FIT image format OK
3043 -140 common/cmd_ide.c Incorrect FIT image format
3044 141 common/cmd_ide.c FIT image format OK
3046 -150 common/cmd_nand.c Incorrect FIT image format
3047 151 common/cmd_nand.c FIT image format OK
3049 - legacy image format:
3050 CONFIG_IMAGE_FORMAT_LEGACY
3051 enables the legacy image format support in U-Boot.
3054 enabled if CONFIG_FIT_SIGNATURE is not defined.
3056 CONFIG_DISABLE_IMAGE_LEGACY
3057 disable the legacy image format
3059 This define is introduced, as the legacy image format is
3060 enabled per default for backward compatibility.
3062 - FIT image support:
3063 CONFIG_FIT_DISABLE_SHA256
3064 Supporting SHA256 hashes has quite an impact on binary size.
3065 For constrained systems sha256 hash support can be disabled
3068 TODO(sjg@chromium.org): Adjust this option to be positive,
3069 and move it to Kconfig
3071 - Standalone program support:
3072 CONFIG_STANDALONE_LOAD_ADDR
3074 This option defines a board specific value for the
3075 address where standalone program gets loaded, thus
3076 overwriting the architecture dependent default
3079 - Frame Buffer Address:
3082 Define CONFIG_FB_ADDR if you want to use specific
3083 address for frame buffer. This is typically the case
3084 when using a graphics controller has separate video
3085 memory. U-Boot will then place the frame buffer at
3086 the given address instead of dynamically reserving it
3087 in system RAM by calling lcd_setmem(), which grabs
3088 the memory for the frame buffer depending on the
3089 configured panel size.
3091 Please see board_init_f function.
3093 - Automatic software updates via TFTP server
3095 CONFIG_UPDATE_TFTP_CNT_MAX
3096 CONFIG_UPDATE_TFTP_MSEC_MAX
3098 These options enable and control the auto-update feature;
3099 for a more detailed description refer to doc/README.update.
3101 - MTD Support (mtdparts command, UBI support)
3104 Adds the MTD device infrastructure from the Linux kernel.
3105 Needed for mtdparts command support.
3107 CONFIG_MTD_PARTITIONS
3109 Adds the MTD partitioning infrastructure from the Linux
3110 kernel. Needed for UBI support.
3115 Adds commands for interacting with MTD partitions formatted
3116 with the UBI flash translation layer
3118 Requires also defining CONFIG_RBTREE
3120 CONFIG_UBI_SILENCE_MSG
3122 Make the verbose messages from UBI stop printing. This leaves
3123 warnings and errors enabled.
3126 CONFIG_MTD_UBI_WL_THRESHOLD
3127 This parameter defines the maximum difference between the highest
3128 erase counter value and the lowest erase counter value of eraseblocks
3129 of UBI devices. When this threshold is exceeded, UBI starts performing
3130 wear leveling by means of moving data from eraseblock with low erase
3131 counter to eraseblocks with high erase counter.
3133 The default value should be OK for SLC NAND flashes, NOR flashes and
3134 other flashes which have eraseblock life-cycle 100000 or more.
3135 However, in case of MLC NAND flashes which typically have eraseblock
3136 life-cycle less than 10000, the threshold should be lessened (e.g.,
3137 to 128 or 256, although it does not have to be power of 2).
3141 CONFIG_MTD_UBI_BEB_LIMIT
3142 This option specifies the maximum bad physical eraseblocks UBI
3143 expects on the MTD device (per 1024 eraseblocks). If the
3144 underlying flash does not admit of bad eraseblocks (e.g. NOR
3145 flash), this value is ignored.
3147 NAND datasheets often specify the minimum and maximum NVM
3148 (Number of Valid Blocks) for the flashes' endurance lifetime.
3149 The maximum expected bad eraseblocks per 1024 eraseblocks
3150 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3151 which gives 20 for most NANDs (MaxNVB is basically the total
3152 count of eraseblocks on the chip).
3154 To put it differently, if this value is 20, UBI will try to
3155 reserve about 1.9% of physical eraseblocks for bad blocks
3156 handling. And that will be 1.9% of eraseblocks on the entire
3157 NAND chip, not just the MTD partition UBI attaches. This means
3158 that if you have, say, a NAND flash chip admits maximum 40 bad
3159 eraseblocks, and it is split on two MTD partitions of the same
3160 size, UBI will reserve 40 eraseblocks when attaching a
3165 CONFIG_MTD_UBI_FASTMAP
3166 Fastmap is a mechanism which allows attaching an UBI device
3167 in nearly constant time. Instead of scanning the whole MTD device it
3168 only has to locate a checkpoint (called fastmap) on the device.
3169 The on-flash fastmap contains all information needed to attach
3170 the device. Using fastmap makes only sense on large devices where
3171 attaching by scanning takes long. UBI will not automatically install
3172 a fastmap on old images, but you can set the UBI parameter
3173 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3174 that fastmap-enabled images are still usable with UBI implementations
3175 without fastmap support. On typical flash devices the whole fastmap
3176 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3178 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3179 Set this parameter to enable fastmap automatically on images
3183 CONFIG_MTD_UBI_FM_DEBUG
3184 Enable UBI fastmap debug
3190 Adds commands for interacting with UBI volumes formatted as
3191 UBIFS. UBIFS is read-only in u-boot.
3193 Requires UBI support as well as CONFIG_LZO
3195 CONFIG_UBIFS_SILENCE_MSG
3197 Make the verbose messages from UBIFS stop printing. This leaves
3198 warnings and errors enabled.
3202 Enable building of SPL globally.
3205 LDSCRIPT for linking the SPL binary.
3207 CONFIG_SPL_MAX_FOOTPRINT
3208 Maximum size in memory allocated to the SPL, BSS included.
3209 When defined, the linker checks that the actual memory
3210 used by SPL from _start to __bss_end does not exceed it.
3211 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3212 must not be both defined at the same time.
3215 Maximum size of the SPL image (text, data, rodata, and
3216 linker lists sections), BSS excluded.
3217 When defined, the linker checks that the actual size does
3220 CONFIG_SPL_TEXT_BASE
3221 TEXT_BASE for linking the SPL binary.
3223 CONFIG_SPL_RELOC_TEXT_BASE
3224 Address to relocate to. If unspecified, this is equal to
3225 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3227 CONFIG_SPL_BSS_START_ADDR
3228 Link address for the BSS within the SPL binary.
3230 CONFIG_SPL_BSS_MAX_SIZE
3231 Maximum size in memory allocated to the SPL BSS.
3232 When defined, the linker checks that the actual memory used
3233 by SPL from __bss_start to __bss_end does not exceed it.
3234 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3235 must not be both defined at the same time.
3238 Adress of the start of the stack SPL will use
3240 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3241 When defined, SPL will panic() if the image it has
3242 loaded does not have a signature.
3243 Defining this is useful when code which loads images
3244 in SPL cannot guarantee that absolutely all read errors
3246 An example is the LPC32XX MLC NAND driver, which will
3247 consider that a completely unreadable NAND block is bad,
3248 and thus should be skipped silently.
3250 CONFIG_SPL_RELOC_STACK
3251 Adress of the start of the stack SPL will use after
3252 relocation. If unspecified, this is equal to
3255 CONFIG_SYS_SPL_MALLOC_START
3256 Starting address of the malloc pool used in SPL.
3257 When this option is set the full malloc is used in SPL and
3258 it is set up by spl_init() and before that, the simple malloc()
3259 can be used if CONFIG_SYS_MALLOC_F is defined.
3261 CONFIG_SYS_SPL_MALLOC_SIZE
3262 The size of the malloc pool used in SPL.
3264 CONFIG_SPL_FRAMEWORK
3265 Enable the SPL framework under common/. This framework
3266 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3267 NAND loading of the Linux Kernel.
3270 Enable booting directly to an OS from SPL.
3271 See also: doc/README.falcon
3273 CONFIG_SPL_DISPLAY_PRINT
3274 For ARM, enable an optional function to print more information
3275 about the running system.
3277 CONFIG_SPL_INIT_MINIMAL
3278 Arch init code should be built for a very small image
3280 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3281 Partition on the MMC to load U-Boot from when the MMC is being
3284 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3285 Sector to load kernel uImage from when MMC is being
3286 used in raw mode (for Falcon mode)
3288 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3289 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3290 Sector and number of sectors to load kernel argument
3291 parameters from when MMC is being used in raw mode
3294 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3295 Partition on the MMC to load U-Boot from when the MMC is being
3298 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3299 Filename to read to load U-Boot when reading from filesystem
3301 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3302 Filename to read to load kernel uImage when reading
3303 from filesystem (for Falcon mode)
3305 CONFIG_SPL_FS_LOAD_ARGS_NAME
3306 Filename to read to load kernel argument parameters
3307 when reading from filesystem (for Falcon mode)
3309 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3310 Set this for NAND SPL on PPC mpc83xx targets, so that
3311 start.S waits for the rest of the SPL to load before
3312 continuing (the hardware starts execution after just
3313 loading the first page rather than the full 4K).
3315 CONFIG_SPL_SKIP_RELOCATE
3316 Avoid SPL relocation
3318 CONFIG_SPL_NAND_BASE
3319 Include nand_base.c in the SPL. Requires
3320 CONFIG_SPL_NAND_DRIVERS.
3322 CONFIG_SPL_NAND_DRIVERS
3323 SPL uses normal NAND drivers, not minimal drivers.
3326 Include standard software ECC in the SPL
3328 CONFIG_SPL_NAND_SIMPLE
3329 Support for NAND boot using simple NAND drivers that
3330 expose the cmd_ctrl() interface.
3333 Support for a lightweight UBI (fastmap) scanner and
3336 CONFIG_SPL_NAND_RAW_ONLY
3337 Support to boot only raw u-boot.bin images. Use this only
3338 if you need to save space.
3340 CONFIG_SPL_COMMON_INIT_DDR
3341 Set for common ddr init with serial presence detect in
3344 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3345 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3346 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3347 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3348 CONFIG_SYS_NAND_ECCBYTES
3349 Defines the size and behavior of the NAND that SPL uses
3352 CONFIG_SPL_NAND_BOOT
3353 Add support NAND boot
3355 CONFIG_SYS_NAND_U_BOOT_OFFS
3356 Location in NAND to read U-Boot from
3358 CONFIG_SYS_NAND_U_BOOT_DST
3359 Location in memory to load U-Boot to
3361 CONFIG_SYS_NAND_U_BOOT_SIZE
3362 Size of image to load
3364 CONFIG_SYS_NAND_U_BOOT_START
3365 Entry point in loaded image to jump to
3367 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3368 Define this if you need to first read the OOB and then the
3369 data. This is used, for example, on davinci platforms.
3371 CONFIG_SPL_OMAP3_ID_NAND
3372 Support for an OMAP3-specific set of functions to return the
3373 ID and MFR of the first attached NAND chip, if present.
3375 CONFIG_SPL_RAM_DEVICE
3376 Support for running image already present in ram, in SPL binary
3379 Image offset to which the SPL should be padded before appending
3380 the SPL payload. By default, this is defined as
3381 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3382 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3383 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3386 Final target image containing SPL and payload. Some SPLs
3387 use an arch-specific makefile fragment instead, for
3388 example if more than one image needs to be produced.
3390 CONFIG_FIT_SPL_PRINT
3391 Printing information about a FIT image adds quite a bit of
3392 code to SPL. So this is normally disabled in SPL. Use this
3393 option to re-enable it. This will affect the output of the
3394 bootm command when booting a FIT image.
3398 Enable building of TPL globally.
3401 Image offset to which the TPL should be padded before appending
3402 the TPL payload. By default, this is defined as
3403 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3404 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3405 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3407 - Interrupt support (PPC):
3409 There are common interrupt_init() and timer_interrupt()
3410 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3411 for CPU specific initialization. interrupt_init_cpu()
3412 should set decrementer_count to appropriate value. If
3413 CPU resets decrementer automatically after interrupt
3414 (ppc4xx) it should set decrementer_count to zero.
3415 timer_interrupt() calls timer_interrupt_cpu() for CPU
3416 specific handling. If board has watchdog / status_led
3417 / other_activity_monitor it works automatically from
3418 general timer_interrupt().
3421 Board initialization settings:
3422 ------------------------------
3424 During Initialization u-boot calls a number of board specific functions
3425 to allow the preparation of board specific prerequisites, e.g. pin setup
3426 before drivers are initialized. To enable these callbacks the
3427 following configuration macros have to be defined. Currently this is
3428 architecture specific, so please check arch/your_architecture/lib/board.c
3429 typically in board_init_f() and board_init_r().
3431 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3432 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3433 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3434 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3436 Configuration Settings:
3437 -----------------------
3439 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3440 Optionally it can be defined to support 64-bit memory commands.
3442 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3443 undefine this when you're short of memory.
3445 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3446 width of the commands listed in the 'help' command output.
3448 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3449 prompt for user input.
3451 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3453 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3455 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3457 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3458 the application (usually a Linux kernel) when it is
3461 - CONFIG_SYS_BAUDRATE_TABLE:
3462 List of legal baudrate settings for this board.
3464 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3465 Begin and End addresses of the area used by the
3468 - CONFIG_SYS_ALT_MEMTEST:
3469 Enable an alternate, more extensive memory test.
3471 - CONFIG_SYS_MEMTEST_SCRATCH:
3472 Scratch address used by the alternate memory test
3473 You only need to set this if address zero isn't writeable
3475 - CONFIG_SYS_MEM_RESERVE_SECURE
3476 Only implemented for ARMv8 for now.
3477 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3478 is substracted from total RAM and won't be reported to OS.
3479 This memory can be used as secure memory. A variable
3480 gd->arch.secure_ram is used to track the location. In systems
3481 the RAM base is not zero, or RAM is divided into banks,
3482 this variable needs to be recalcuated to get the address.
3484 - CONFIG_SYS_MEM_TOP_HIDE:
3485 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3486 this specified memory area will get subtracted from the top
3487 (end) of RAM and won't get "touched" at all by U-Boot. By
3488 fixing up gd->ram_size the Linux kernel should gets passed
3489 the now "corrected" memory size and won't touch it either.
3490 This should work for arch/ppc and arch/powerpc. Only Linux
3491 board ports in arch/powerpc with bootwrapper support that
3492 recalculate the memory size from the SDRAM controller setup
3493 will have to get fixed in Linux additionally.
3495 This option can be used as a workaround for the 440EPx/GRx
3496 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3499 WARNING: Please make sure that this value is a multiple of
3500 the Linux page size (normally 4k). If this is not the case,
3501 then the end address of the Linux memory will be located at a
3502 non page size aligned address and this could cause major
3505 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3506 Enable temporary baudrate change while serial download
3508 - CONFIG_SYS_SDRAM_BASE:
3509 Physical start address of SDRAM. _Must_ be 0 here.
3511 - CONFIG_SYS_FLASH_BASE:
3512 Physical start address of Flash memory.
3514 - CONFIG_SYS_MONITOR_BASE:
3515 Physical start address of boot monitor code (set by
3516 make config files to be same as the text base address
3517 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3518 CONFIG_SYS_FLASH_BASE when booting from flash.
3520 - CONFIG_SYS_MONITOR_LEN:
3521 Size of memory reserved for monitor code, used to
3522 determine _at_compile_time_ (!) if the environment is
3523 embedded within the U-Boot image, or in a separate
3526 - CONFIG_SYS_MALLOC_LEN:
3527 Size of DRAM reserved for malloc() use.
3529 - CONFIG_SYS_MALLOC_F_LEN
3530 Size of the malloc() pool for use before relocation. If
3531 this is defined, then a very simple malloc() implementation
3532 will become available before relocation. The address is just
3533 below the global data, and the stack is moved down to make
3536 This feature allocates regions with increasing addresses
3537 within the region. calloc() is supported, but realloc()
3538 is not available. free() is supported but does nothing.
3539 The memory will be freed (or in fact just forgotten) when
3540 U-Boot relocates itself.
3542 - CONFIG_SYS_MALLOC_SIMPLE
3543 Provides a simple and small malloc() and calloc() for those
3544 boards which do not use the full malloc in SPL (which is
3545 enabled with CONFIG_SYS_SPL_MALLOC_START).
3547 - CONFIG_SYS_NONCACHED_MEMORY:
3548 Size of non-cached memory area. This area of memory will be
3549 typically located right below the malloc() area and mapped
3550 uncached in the MMU. This is useful for drivers that would
3551 otherwise require a lot of explicit cache maintenance. For
3552 some drivers it's also impossible to properly maintain the
3553 cache. For example if the regions that need to be flushed
3554 are not a multiple of the cache-line size, *and* padding
3555 cannot be allocated between the regions to align them (i.e.
3556 if the HW requires a contiguous array of regions, and the
3557 size of each region is not cache-aligned), then a flush of
3558 one region may result in overwriting data that hardware has
3559 written to another region in the same cache-line. This can
3560 happen for example in network drivers where descriptors for
3561 buffers are typically smaller than the CPU cache-line (e.g.
3562 16 bytes vs. 32 or 64 bytes).
3564 Non-cached memory is only supported on 32-bit ARM at present.
3566 - CONFIG_SYS_BOOTM_LEN:
3567 Normally compressed uImages are limited to an
3568 uncompressed size of 8 MBytes. If this is not enough,
3569 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3570 to adjust this setting to your needs.
3572 - CONFIG_SYS_BOOTMAPSZ:
3573 Maximum size of memory mapped by the startup code of
3574 the Linux kernel; all data that must be processed by
3575 the Linux kernel (bd_info, boot arguments, FDT blob if
3576 used) must be put below this limit, unless "bootm_low"
3577 environment variable is defined and non-zero. In such case
3578 all data for the Linux kernel must be between "bootm_low"
3579 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3580 variable "bootm_mapsize" will override the value of
3581 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3582 then the value in "bootm_size" will be used instead.
3584 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3585 Enable initrd_high functionality. If defined then the
3586 initrd_high feature is enabled and the bootm ramdisk subcommand
3589 - CONFIG_SYS_BOOT_GET_CMDLINE:
3590 Enables allocating and saving kernel cmdline in space between
3591 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3593 - CONFIG_SYS_BOOT_GET_KBD:
3594 Enables allocating and saving a kernel copy of the bd_info in
3595 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3597 - CONFIG_SYS_MAX_FLASH_BANKS:
3598 Max number of Flash memory banks
3600 - CONFIG_SYS_MAX_FLASH_SECT:
3601 Max number of sectors on a Flash chip
3603 - CONFIG_SYS_FLASH_ERASE_TOUT:
3604 Timeout for Flash erase operations (in ms)
3606 - CONFIG_SYS_FLASH_WRITE_TOUT:
3607 Timeout for Flash write operations (in ms)
3609 - CONFIG_SYS_FLASH_LOCK_TOUT
3610 Timeout for Flash set sector lock bit operation (in ms)
3612 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3613 Timeout for Flash clear lock bits operation (in ms)
3615 - CONFIG_SYS_FLASH_PROTECTION
3616 If defined, hardware flash sectors protection is used
3617 instead of U-Boot software protection.
3619 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3621 Enable TFTP transfers directly to flash memory;
3622 without this option such a download has to be
3623 performed in two steps: (1) download to RAM, and (2)
3624 copy from RAM to flash.
3626 The two-step approach is usually more reliable, since
3627 you can check if the download worked before you erase
3628 the flash, but in some situations (when system RAM is
3629 too limited to allow for a temporary copy of the
3630 downloaded image) this option may be very useful.
3632 - CONFIG_SYS_FLASH_CFI:
3633 Define if the flash driver uses extra elements in the
3634 common flash structure for storing flash geometry.
3636 - CONFIG_FLASH_CFI_DRIVER
3637 This option also enables the building of the cfi_flash driver
3638 in the drivers directory
3640 - CONFIG_FLASH_CFI_MTD
3641 This option enables the building of the cfi_mtd driver
3642 in the drivers directory. The driver exports CFI flash
3645 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3646 Use buffered writes to flash.
3648 - CONFIG_FLASH_SPANSION_S29WS_N
3649 s29ws-n MirrorBit flash has non-standard addresses for buffered
3652 - CONFIG_SYS_FLASH_QUIET_TEST
3653 If this option is defined, the common CFI flash doesn't
3654 print it's warning upon not recognized FLASH banks. This
3655 is useful, if some of the configured banks are only
3656 optionally available.
3658 - CONFIG_FLASH_SHOW_PROGRESS
3659 If defined (must be an integer), print out countdown
3660 digits and dots. Recommended value: 45 (9..1) for 80
3661 column displays, 15 (3..1) for 40 column displays.
3663 - CONFIG_FLASH_VERIFY
3664 If defined, the content of the flash (destination) is compared
3665 against the source after the write operation. An error message
3666 will be printed when the contents are not identical.
3667 Please note that this option is useless in nearly all cases,
3668 since such flash programming errors usually are detected earlier
3669 while unprotecting/erasing/programming. Please only enable
3670 this option if you really know what you are doing.
3672 - CONFIG_SYS_RX_ETH_BUFFER:
3673 Defines the number of Ethernet receive buffers. On some
3674 Ethernet controllers it is recommended to set this value
3675 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3676 buffers can be full shortly after enabling the interface
3677 on high Ethernet traffic.
3678 Defaults to 4 if not defined.
3680 - CONFIG_ENV_MAX_ENTRIES
3682 Maximum number of entries in the hash table that is used
3683 internally to store the environment settings. The default
3684 setting is supposed to be generous and should work in most
3685 cases. This setting can be used to tune behaviour; see
3686 lib/hashtable.c for details.
3688 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3689 - CONFIG_ENV_FLAGS_LIST_STATIC
3690 Enable validation of the values given to environment variables when
3691 calling env set. Variables can be restricted to only decimal,
3692 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3693 the variables can also be restricted to IP address or MAC address.
3695 The format of the list is:
3696 type_attribute = [s|d|x|b|i|m]
3697 access_attribute = [a|r|o|c]
3698 attributes = type_attribute[access_attribute]
3699 entry = variable_name[:attributes]
3702 The type attributes are:
3703 s - String (default)
3706 b - Boolean ([1yYtT|0nNfF])
3710 The access attributes are:
3716 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3717 Define this to a list (string) to define the ".flags"
3718 environment variable in the default or embedded environment.
3720 - CONFIG_ENV_FLAGS_LIST_STATIC
3721 Define this to a list (string) to define validation that
3722 should be done if an entry is not found in the ".flags"
3723 environment variable. To override a setting in the static
3724 list, simply add an entry for the same variable name to the
3727 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3728 regular expression. This allows multiple variables to define the same
3729 flags without explicitly listing them for each variable.
3731 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3732 If defined, don't allow the -f switch to env set override variable
3735 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3736 This is set by OMAP boards for the max time that reset should
3737 be asserted. See doc/README.omap-reset-time for details on how
3738 the value can be calculated on a given board.
3741 If stdint.h is available with your toolchain you can define this
3742 option to enable it. You can provide option 'USE_STDINT=1' when
3743 building U-Boot to enable this.
3745 The following definitions that deal with the placement and management
3746 of environment data (variable area); in general, we support the
3747 following configurations:
3749 - CONFIG_BUILD_ENVCRC:
3751 Builds up envcrc with the target environment so that external utils
3752 may easily extract it and embed it in final U-Boot images.
3754 - CONFIG_ENV_IS_IN_FLASH:
3756 Define this if the environment is in flash memory.
3758 a) The environment occupies one whole flash sector, which is
3759 "embedded" in the text segment with the U-Boot code. This
3760 happens usually with "bottom boot sector" or "top boot
3761 sector" type flash chips, which have several smaller
3762 sectors at the start or the end. For instance, such a
3763 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3764 such a case you would place the environment in one of the
3765 4 kB sectors - with U-Boot code before and after it. With
3766 "top boot sector" type flash chips, you would put the
3767 environment in one of the last sectors, leaving a gap
3768 between U-Boot and the environment.
3770 - CONFIG_ENV_OFFSET:
3772 Offset of environment data (variable area) to the
3773 beginning of flash memory; for instance, with bottom boot
3774 type flash chips the second sector can be used: the offset
3775 for this sector is given here.
3777 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3781 This is just another way to specify the start address of
3782 the flash sector containing the environment (instead of
3785 - CONFIG_ENV_SECT_SIZE:
3787 Size of the sector containing the environment.
3790 b) Sometimes flash chips have few, equal sized, BIG sectors.
3791 In such a case you don't want to spend a whole sector for
3796 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3797 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3798 of this flash sector for the environment. This saves
3799 memory for the RAM copy of the environment.
3801 It may also save flash memory if you decide to use this
3802 when your environment is "embedded" within U-Boot code,
3803 since then the remainder of the flash sector could be used
3804 for U-Boot code. It should be pointed out that this is
3805 STRONGLY DISCOURAGED from a robustness point of view:
3806 updating the environment in flash makes it always
3807 necessary to erase the WHOLE sector. If something goes
3808 wrong before the contents has been restored from a copy in
3809 RAM, your target system will be dead.
3811 - CONFIG_ENV_ADDR_REDUND
3812 CONFIG_ENV_SIZE_REDUND
3814 These settings describe a second storage area used to hold
3815 a redundant copy of the environment data, so that there is
3816 a valid backup copy in case there is a power failure during
3817 a "saveenv" operation.
3819 BE CAREFUL! Any changes to the flash layout, and some changes to the
3820 source code will make it necessary to adapt <board>/u-boot.lds*
3824 - CONFIG_ENV_IS_IN_NVRAM:
3826 Define this if you have some non-volatile memory device
3827 (NVRAM, battery buffered SRAM) which you want to use for the
3833 These two #defines are used to determine the memory area you
3834 want to use for environment. It is assumed that this memory
3835 can just be read and written to, without any special
3838 BE CAREFUL! The first access to the environment happens quite early
3839 in U-Boot initialization (when we try to get the setting of for the
3840 console baudrate). You *MUST* have mapped your NVRAM area then, or
3843 Please note that even with NVRAM we still use a copy of the
3844 environment in RAM: we could work on NVRAM directly, but we want to
3845 keep settings there always unmodified except somebody uses "saveenv"
3846 to save the current settings.
3849 - CONFIG_ENV_IS_IN_EEPROM:
3851 Use this if you have an EEPROM or similar serial access
3852 device and a driver for it.
3854 - CONFIG_ENV_OFFSET:
3857 These two #defines specify the offset and size of the
3858 environment area within the total memory of your EEPROM.
3860 - CONFIG_SYS_I2C_EEPROM_ADDR:
3861 If defined, specified the chip address of the EEPROM device.
3862 The default address is zero.
3864 - CONFIG_SYS_I2C_EEPROM_BUS:
3865 If defined, specified the i2c bus of the EEPROM device.
3867 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3868 If defined, the number of bits used to address bytes in a
3869 single page in the EEPROM device. A 64 byte page, for example
3870 would require six bits.
3872 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3873 If defined, the number of milliseconds to delay between
3874 page writes. The default is zero milliseconds.
3876 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3877 The length in bytes of the EEPROM memory array address. Note
3878 that this is NOT the chip address length!
3880 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3881 EEPROM chips that implement "address overflow" are ones
3882 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3883 address and the extra bits end up in the "chip address" bit
3884 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3887 Note that we consider the length of the address field to
3888 still be one byte because the extra address bits are hidden
3889 in the chip address.
3891 - CONFIG_SYS_EEPROM_SIZE:
3892 The size in bytes of the EEPROM device.
3894 - CONFIG_ENV_EEPROM_IS_ON_I2C
3895 define this, if you have I2C and SPI activated, and your
3896 EEPROM, which holds the environment, is on the I2C bus.
3898 - CONFIG_I2C_ENV_EEPROM_BUS
3899 if you have an Environment on an EEPROM reached over
3900 I2C muxes, you can define here, how to reach this
3901 EEPROM. For example:
3903 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3905 EEPROM which holds the environment, is reached over
3906 a pca9547 i2c mux with address 0x70, channel 3.
3908 - CONFIG_ENV_IS_IN_DATAFLASH:
3910 Define this if you have a DataFlash memory device which you
3911 want to use for the environment.
3913 - CONFIG_ENV_OFFSET:
3917 These three #defines specify the offset and size of the
3918 environment area within the total memory of your DataFlash placed
3919 at the specified address.
3921 - CONFIG_ENV_IS_IN_SPI_FLASH:
3923 Define this if you have a SPI Flash memory device which you
3924 want to use for the environment.
3926 - CONFIG_ENV_OFFSET:
3929 These two #defines specify the offset and size of the
3930 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3931 aligned to an erase sector boundary.
3933 - CONFIG_ENV_SECT_SIZE:
3935 Define the SPI flash's sector size.
3937 - CONFIG_ENV_OFFSET_REDUND (optional):
3939 This setting describes a second storage area of CONFIG_ENV_SIZE
3940 size used to hold a redundant copy of the environment data, so
3941 that there is a valid backup copy in case there is a power failure
3942 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3943 aligned to an erase sector boundary.
3945 - CONFIG_ENV_SPI_BUS (optional):
3946 - CONFIG_ENV_SPI_CS (optional):
3948 Define the SPI bus and chip select. If not defined they will be 0.
3950 - CONFIG_ENV_SPI_MAX_HZ (optional):
3952 Define the SPI max work clock. If not defined then use 1MHz.
3954 - CONFIG_ENV_SPI_MODE (optional):
3956 Define the SPI work mode. If not defined then use SPI_MODE_3.
3958 - CONFIG_ENV_IS_IN_REMOTE:
3960 Define this if you have a remote memory space which you
3961 want to use for the local device's environment.
3966 These two #defines specify the address and size of the
3967 environment area within the remote memory space. The
3968 local device can get the environment from remote memory
3969 space by SRIO or PCIE links.
3971 BE CAREFUL! For some special cases, the local device can not use
3972 "saveenv" command. For example, the local device will get the
3973 environment stored in a remote NOR flash by SRIO or PCIE link,
3974 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3976 - CONFIG_ENV_IS_IN_NAND:
3978 Define this if you have a NAND device which you want to use
3979 for the environment.
3981 - CONFIG_ENV_OFFSET:
3984 These two #defines specify the offset and size of the environment
3985 area within the first NAND device. CONFIG_ENV_OFFSET must be
3986 aligned to an erase block boundary.
3988 - CONFIG_ENV_OFFSET_REDUND (optional):
3990 This setting describes a second storage area of CONFIG_ENV_SIZE
3991 size used to hold a redundant copy of the environment data, so
3992 that there is a valid backup copy in case there is a power failure
3993 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3994 aligned to an erase block boundary.
3996 - CONFIG_ENV_RANGE (optional):
3998 Specifies the length of the region in which the environment
3999 can be written. This should be a multiple of the NAND device's
4000 block size. Specifying a range with more erase blocks than
4001 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4002 the range to be avoided.
4004 - CONFIG_ENV_OFFSET_OOB (optional):
4006 Enables support for dynamically retrieving the offset of the
4007 environment from block zero's out-of-band data. The
4008 "nand env.oob" command can be used to record this offset.
4009 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4010 using CONFIG_ENV_OFFSET_OOB.
4012 - CONFIG_NAND_ENV_DST
4014 Defines address in RAM to which the nand_spl code should copy the
4015 environment. If redundant environment is used, it will be copied to
4016 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4018 - CONFIG_ENV_IS_IN_UBI:
4020 Define this if you have an UBI volume that you want to use for the
4021 environment. This has the benefit of wear-leveling the environment
4022 accesses, which is important on NAND.
4024 - CONFIG_ENV_UBI_PART:
4026 Define this to a string that is the mtd partition containing the UBI.
4028 - CONFIG_ENV_UBI_VOLUME:
4030 Define this to the name of the volume that you want to store the
4033 - CONFIG_ENV_UBI_VOLUME_REDUND:
4035 Define this to the name of another volume to store a second copy of
4036 the environment in. This will enable redundant environments in UBI.
4037 It is assumed that both volumes are in the same MTD partition.
4039 - CONFIG_UBI_SILENCE_MSG
4040 - CONFIG_UBIFS_SILENCE_MSG
4042 You will probably want to define these to avoid a really noisy system
4043 when storing the env in UBI.
4045 - CONFIG_ENV_IS_IN_FAT:
4046 Define this if you want to use the FAT file system for the environment.
4048 - FAT_ENV_INTERFACE:
4050 Define this to a string that is the name of the block device.
4052 - FAT_ENV_DEVICE_AND_PART:
4054 Define this to a string to specify the partition of the device. It can
4057 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4058 - "D:P": device D partition P. Error occurs if device D has no
4061 - "D" or "D:": device D partition 1 if device D has partition
4062 table, or the whole device D if has no partition
4064 - "D:auto": first partition in device D with bootable flag set.
4065 If none, first valid partition in device D. If no
4066 partition table then means device D.
4070 It's a string of the FAT file name. This file use to store the
4074 This should be defined. Otherwise it cannot save the environment file.
4076 - CONFIG_ENV_IS_IN_MMC:
4078 Define this if you have an MMC device which you want to use for the
4081 - CONFIG_SYS_MMC_ENV_DEV:
4083 Specifies which MMC device the environment is stored in.
4085 - CONFIG_SYS_MMC_ENV_PART (optional):
4087 Specifies which MMC partition the environment is stored in. If not
4088 set, defaults to partition 0, the user area. Common values might be
4089 1 (first MMC boot partition), 2 (second MMC boot partition).
4091 - CONFIG_ENV_OFFSET:
4094 These two #defines specify the offset and size of the environment
4095 area within the specified MMC device.
4097 If offset is positive (the usual case), it is treated as relative to
4098 the start of the MMC partition. If offset is negative, it is treated
4099 as relative to the end of the MMC partition. This can be useful if
4100 your board may be fitted with different MMC devices, which have
4101 different sizes for the MMC partitions, and you always want the
4102 environment placed at the very end of the partition, to leave the
4103 maximum possible space before it, to store other data.
4105 These two values are in units of bytes, but must be aligned to an
4106 MMC sector boundary.
4108 - CONFIG_ENV_OFFSET_REDUND (optional):
4110 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4111 hold a redundant copy of the environment data. This provides a
4112 valid backup copy in case the other copy is corrupted, e.g. due
4113 to a power failure during a "saveenv" operation.
4115 This value may also be positive or negative; this is handled in the
4116 same way as CONFIG_ENV_OFFSET.
4118 This value is also in units of bytes, but must also be aligned to
4119 an MMC sector boundary.
4121 - CONFIG_ENV_SIZE_REDUND (optional):
4123 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4124 set. If this value is set, it must be set to the same value as
4127 - CONFIG_SYS_SPI_INIT_OFFSET
4129 Defines offset to the initial SPI buffer area in DPRAM. The
4130 area is used at an early stage (ROM part) if the environment
4131 is configured to reside in the SPI EEPROM: We need a 520 byte
4132 scratch DPRAM area. It is used between the two initialization
4133 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4134 to be a good choice since it makes it far enough from the
4135 start of the data area as well as from the stack pointer.
4137 Please note that the environment is read-only until the monitor
4138 has been relocated to RAM and a RAM copy of the environment has been
4139 created; also, when using EEPROM you will have to use getenv_f()
4140 until then to read environment variables.
4142 The environment is protected by a CRC32 checksum. Before the monitor
4143 is relocated into RAM, as a result of a bad CRC you will be working
4144 with the compiled-in default environment - *silently*!!! [This is
4145 necessary, because the first environment variable we need is the
4146 "baudrate" setting for the console - if we have a bad CRC, we don't
4147 have any device yet where we could complain.]
4149 Note: once the monitor has been relocated, then it will complain if
4150 the default environment is used; a new CRC is computed as soon as you
4151 use the "saveenv" command to store a valid environment.
4153 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4154 Echo the inverted Ethernet link state to the fault LED.
4156 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4157 also needs to be defined.
4159 - CONFIG_SYS_FAULT_MII_ADDR:
4160 MII address of the PHY to check for the Ethernet link state.
4162 - CONFIG_NS16550_MIN_FUNCTIONS:
4163 Define this if you desire to only have use of the NS16550_init
4164 and NS16550_putc functions for the serial driver located at
4165 drivers/serial/ns16550.c. This option is useful for saving
4166 space for already greatly restricted images, including but not
4167 limited to NAND_SPL configurations.
4169 - CONFIG_DISPLAY_BOARDINFO
4170 Display information about the board that U-Boot is running on
4171 when U-Boot starts up. The board function checkboard() is called
4174 - CONFIG_DISPLAY_BOARDINFO_LATE
4175 Similar to the previous option, but display this information
4176 later, once stdio is running and output goes to the LCD, if
4179 - CONFIG_BOARD_SIZE_LIMIT:
4180 Maximum size of the U-Boot image. When defined, the
4181 build system checks that the actual size does not
4184 Low Level (hardware related) configuration options:
4185 ---------------------------------------------------
4187 - CONFIG_SYS_CACHELINE_SIZE:
4188 Cache Line Size of the CPU.
4190 - CONFIG_SYS_DEFAULT_IMMR:
4191 Default address of the IMMR after system reset.
4193 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4194 and RPXsuper) to be able to adjust the position of
4195 the IMMR register after a reset.
4197 - CONFIG_SYS_CCSRBAR_DEFAULT:
4198 Default (power-on reset) physical address of CCSR on Freescale
4201 - CONFIG_SYS_CCSRBAR:
4202 Virtual address of CCSR. On a 32-bit build, this is typically
4203 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4205 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4206 for cross-platform code that uses that macro instead.
4208 - CONFIG_SYS_CCSRBAR_PHYS:
4209 Physical address of CCSR. CCSR can be relocated to a new
4210 physical address, if desired. In this case, this macro should
4211 be set to that address. Otherwise, it should be set to the
4212 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4213 is typically relocated on 36-bit builds. It is recommended
4214 that this macro be defined via the _HIGH and _LOW macros:
4216 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4217 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4219 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4220 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4221 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4222 used in assembly code, so it must not contain typecasts or
4223 integer size suffixes (e.g. "ULL").
4225 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4226 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4227 used in assembly code, so it must not contain typecasts or
4228 integer size suffixes (e.g. "ULL").
4230 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4231 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4232 forced to a value that ensures that CCSR is not relocated.
4234 - Floppy Disk Support:
4235 CONFIG_SYS_FDC_DRIVE_NUMBER
4237 the default drive number (default value 0)
4239 CONFIG_SYS_ISA_IO_STRIDE
4241 defines the spacing between FDC chipset registers
4244 CONFIG_SYS_ISA_IO_OFFSET
4246 defines the offset of register from address. It
4247 depends on which part of the data bus is connected to
4248 the FDC chipset. (default value 0)
4250 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4251 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4254 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4255 fdc_hw_init() is called at the beginning of the FDC
4256 setup. fdc_hw_init() must be provided by the board
4257 source code. It is used to make hardware-dependent
4261 Most IDE controllers were designed to be connected with PCI
4262 interface. Only few of them were designed for AHB interface.
4263 When software is doing ATA command and data transfer to
4264 IDE devices through IDE-AHB controller, some additional
4265 registers accessing to these kind of IDE-AHB controller
4268 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4269 DO NOT CHANGE unless you know exactly what you're
4270 doing! (11-4) [MPC8xx/82xx systems only]
4272 - CONFIG_SYS_INIT_RAM_ADDR:
4274 Start address of memory area that can be used for
4275 initial data and stack; please note that this must be
4276 writable memory that is working WITHOUT special
4277 initialization, i. e. you CANNOT use normal RAM which
4278 will become available only after programming the
4279 memory controller and running certain initialization
4282 U-Boot uses the following memory types:
4283 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4284 - MPC824X: data cache
4285 - PPC4xx: data cache
4287 - CONFIG_SYS_GBL_DATA_OFFSET:
4289 Offset of the initial data structure in the memory
4290 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4291 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4292 data is located at the end of the available space
4293 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4294 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4295 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4296 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4299 On the MPC824X (or other systems that use the data
4300 cache for initial memory) the address chosen for
4301 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4302 point to an otherwise UNUSED address space between
4303 the top of RAM and the start of the PCI space.
4305 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4307 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4309 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4311 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4313 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4315 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4317 - CONFIG_SYS_OR_TIMING_SDRAM:
4320 - CONFIG_SYS_MAMR_PTA:
4321 periodic timer for refresh
4323 - CONFIG_SYS_DER: Debug Event Register (37-47)
4325 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4326 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4327 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4328 CONFIG_SYS_BR1_PRELIM:
4329 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4331 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4332 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4333 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4334 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4336 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4337 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4338 Machine Mode Register and Memory Periodic Timer
4339 Prescaler definitions (SDRAM timing)
4341 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4342 enable I2C microcode relocation patch (MPC8xx);
4343 define relocation offset in DPRAM [DSP2]
4345 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4346 enable SMC microcode relocation patch (MPC8xx);
4347 define relocation offset in DPRAM [SMC1]
4349 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4350 enable SPI microcode relocation patch (MPC8xx);
4351 define relocation offset in DPRAM [SCC4]
4353 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4354 Offset of the bootmode word in DPRAM used by post
4355 (Power On Self Tests). This definition overrides
4356 #define'd default value in commproc.h resp.
4359 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4360 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4361 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4362 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4363 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4364 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4365 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4366 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4367 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4369 - CONFIG_PCI_DISABLE_PCIE:
4370 Disable PCI-Express on systems where it is supported but not
4373 - CONFIG_PCI_ENUM_ONLY
4374 Only scan through and get the devices on the buses.
4375 Don't do any setup work, presumably because someone or
4376 something has already done it, and we don't need to do it
4377 a second time. Useful for platforms that are pre-booted
4378 by coreboot or similar.
4380 - CONFIG_PCI_INDIRECT_BRIDGE:
4381 Enable support for indirect PCI bridges.
4384 Chip has SRIO or not
4387 Board has SRIO 1 port available
4390 Board has SRIO 2 port available
4392 - CONFIG_SRIO_PCIE_BOOT_MASTER
4393 Board can support master function for Boot from SRIO and PCIE
4395 - CONFIG_SYS_SRIOn_MEM_VIRT:
4396 Virtual Address of SRIO port 'n' memory region
4398 - CONFIG_SYS_SRIOn_MEM_PHYS:
4399 Physical Address of SRIO port 'n' memory region
4401 - CONFIG_SYS_SRIOn_MEM_SIZE:
4402 Size of SRIO port 'n' memory region
4404 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4405 Defined to tell the NAND controller that the NAND chip is using
4407 Not all NAND drivers use this symbol.
4408 Example of drivers that use it:
4409 - drivers/mtd/nand/ndfc.c
4410 - drivers/mtd/nand/mxc_nand.c
4412 - CONFIG_SYS_NDFC_EBC0_CFG
4413 Sets the EBC0_CFG register for the NDFC. If not defined
4414 a default value will be used.
4417 Get DDR timing information from an I2C EEPROM. Common
4418 with pluggable memory modules such as SODIMMs
4421 I2C address of the SPD EEPROM
4423 - CONFIG_SYS_SPD_BUS_NUM
4424 If SPD EEPROM is on an I2C bus other than the first
4425 one, specify here. Note that the value must resolve
4426 to something your driver can deal with.
4428 - CONFIG_SYS_DDR_RAW_TIMING
4429 Get DDR timing information from other than SPD. Common with
4430 soldered DDR chips onboard without SPD. DDR raw timing
4431 parameters are extracted from datasheet and hard-coded into
4432 header files or board specific files.
4434 - CONFIG_FSL_DDR_INTERACTIVE
4435 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4437 - CONFIG_FSL_DDR_SYNC_REFRESH
4438 Enable sync of refresh for multiple controllers.
4440 - CONFIG_FSL_DDR_BIST
4441 Enable built-in memory test for Freescale DDR controllers.
4443 - CONFIG_SYS_83XX_DDR_USES_CS0
4444 Only for 83xx systems. If specified, then DDR should
4445 be configured using CS0 and CS1 instead of CS2 and CS3.
4447 - CONFIG_ETHER_ON_FEC[12]
4448 Define to enable FEC[12] on a 8xx series processor.
4450 - CONFIG_FEC[12]_PHY
4451 Define to the hardcoded PHY address which corresponds
4452 to the given FEC; i. e.
4453 #define CONFIG_FEC1_PHY 4
4454 means that the PHY with address 4 is connected to FEC1
4456 When set to -1, means to probe for first available.
4458 - CONFIG_FEC[12]_PHY_NORXERR
4459 The PHY does not have a RXERR line (RMII only).
4460 (so program the FEC to ignore it).
4463 Enable RMII mode for all FECs.
4464 Note that this is a global option, we can't
4465 have one FEC in standard MII mode and another in RMII mode.
4467 - CONFIG_CRC32_VERIFY
4468 Add a verify option to the crc32 command.
4471 => crc32 -v <address> <count> <crc32>
4473 Where address/count indicate a memory area
4474 and crc32 is the correct crc32 which the
4478 Add the "loopw" memory command. This only takes effect if
4479 the memory commands are activated globally (CONFIG_CMD_MEM).
4482 Add the "mdc" and "mwc" memory commands. These are cyclic
4487 This command will print 4 bytes (10,11,12,13) each 500 ms.
4489 => mwc.l 100 12345678 10
4490 This command will write 12345678 to address 100 all 10 ms.
4492 This only takes effect if the memory commands are activated
4493 globally (CONFIG_CMD_MEM).
4495 - CONFIG_SKIP_LOWLEVEL_INIT
4496 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4497 low level initializations (like setting up the memory
4498 controller) are omitted and/or U-Boot does not
4499 relocate itself into RAM.
4501 Normally this variable MUST NOT be defined. The only
4502 exception is when U-Boot is loaded (to RAM) by some
4503 other boot loader or by a debugger which performs
4504 these initializations itself.
4506 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4507 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4508 to be skipped. The normal CP15 init (such as enabling the
4509 instruction cache) is still performed.
4512 Modifies the behaviour of start.S when compiling a loader
4513 that is executed before the actual U-Boot. E.g. when
4514 compiling a NAND SPL.
4517 Modifies the behaviour of start.S when compiling a loader
4518 that is executed after the SPL and before the actual U-Boot.
4519 It is loaded by the SPL.
4521 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4522 Only for 85xx systems. If this variable is specified, the section
4523 .resetvec is not kept and the section .bootpg is placed in the
4524 previous 4k of the .text section.
4526 - CONFIG_ARCH_MAP_SYSMEM
4527 Generally U-Boot (and in particular the md command) uses
4528 effective address. It is therefore not necessary to regard
4529 U-Boot address as virtual addresses that need to be translated
4530 to physical addresses. However, sandbox requires this, since
4531 it maintains its own little RAM buffer which contains all
4532 addressable memory. This option causes some memory accesses
4533 to be mapped through map_sysmem() / unmap_sysmem().
4535 - CONFIG_X86_RESET_VECTOR
4536 If defined, the x86 reset vector code is included. This is not
4537 needed when U-Boot is running from Coreboot.
4540 Defines the MPU clock speed (in MHz).
4542 NOTE : currently only supported on AM335x platforms.
4544 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4545 Enables the RTC32K OSC on AM33xx based plattforms
4547 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4548 Option to disable subpage write in NAND driver
4549 driver that uses this:
4550 drivers/mtd/nand/davinci_nand.c
4552 Freescale QE/FMAN Firmware Support:
4553 -----------------------------------
4555 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4556 loading of "firmware", which is encoded in the QE firmware binary format.
4557 This firmware often needs to be loaded during U-Boot booting, so macros
4558 are used to identify the storage device (NOR flash, SPI, etc) and the address
4561 - CONFIG_SYS_FMAN_FW_ADDR
4562 The address in the storage device where the FMAN microcode is located. The
4563 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4566 - CONFIG_SYS_QE_FW_ADDR
4567 The address in the storage device where the QE microcode is located. The
4568 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4571 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4572 The maximum possible size of the firmware. The firmware binary format
4573 has a field that specifies the actual size of the firmware, but it
4574 might not be possible to read any part of the firmware unless some
4575 local storage is allocated to hold the entire firmware first.
4577 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4578 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4579 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4580 virtual address in NOR flash.
4582 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4583 Specifies that QE/FMAN firmware is located in NAND flash.
4584 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4586 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4587 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4588 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4590 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4591 Specifies that QE/FMAN firmware is located in the remote (master)
4592 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4593 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4594 window->master inbound window->master LAW->the ucode address in
4595 master's memory space.
4597 Freescale Layerscape Management Complex Firmware Support:
4598 ---------------------------------------------------------
4599 The Freescale Layerscape Management Complex (MC) supports the loading of
4601 This firmware often needs to be loaded during U-Boot booting, so macros
4602 are used to identify the storage device (NOR flash, SPI, etc) and the address
4605 - CONFIG_FSL_MC_ENET
4606 Enable the MC driver for Layerscape SoCs.
4608 Freescale Layerscape Debug Server Support:
4609 -------------------------------------------
4610 The Freescale Layerscape Debug Server Support supports the loading of
4611 "Debug Server firmware" and triggering SP boot-rom.
4612 This firmware often needs to be loaded during U-Boot booting.
4614 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4615 Define alignment of reserved memory MC requires
4620 In order to achieve reproducible builds, timestamps used in the U-Boot build
4621 process have to be set to a fixed value.
4623 This is done using the SOURCE_DATE_EPOCH environment variable.
4624 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4625 option for U-Boot or an environment variable in U-Boot.
4627 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4629 Building the Software:
4630 ======================
4632 Building U-Boot has been tested in several native build environments
4633 and in many different cross environments. Of course we cannot support
4634 all possibly existing versions of cross development tools in all
4635 (potentially obsolete) versions. In case of tool chain problems we
4636 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4637 which is extensively used to build and test U-Boot.
4639 If you are not using a native environment, it is assumed that you
4640 have GNU cross compiling tools available in your path. In this case,
4641 you must set the environment variable CROSS_COMPILE in your shell.
4642 Note that no changes to the Makefile or any other source files are
4643 necessary. For example using the ELDK on a 4xx CPU, please enter:
4645 $ CROSS_COMPILE=ppc_4xx-
4646 $ export CROSS_COMPILE
4648 Note: If you wish to generate Windows versions of the utilities in
4649 the tools directory you can use the MinGW toolchain
4650 (http://www.mingw.org). Set your HOST tools to the MinGW
4651 toolchain and execute 'make tools'. For example:
4653 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4655 Binaries such as tools/mkimage.exe will be created which can
4656 be executed on computers running Windows.
4658 U-Boot is intended to be simple to build. After installing the
4659 sources you must configure U-Boot for one specific board type. This
4664 where "NAME_defconfig" is the name of one of the existing configu-
4665 rations; see boards.cfg for supported names.
4667 Note: for some board special configuration names may exist; check if
4668 additional information is available from the board vendor; for
4669 instance, the TQM823L systems are available without (standard)
4670 or with LCD support. You can select such additional "features"
4671 when choosing the configuration, i. e.
4673 make TQM823L_defconfig
4674 - will configure for a plain TQM823L, i. e. no LCD support
4676 make TQM823L_LCD_defconfig
4677 - will configure for a TQM823L with U-Boot console on LCD
4682 Finally, type "make all", and you should get some working U-Boot
4683 images ready for download to / installation on your system:
4685 - "u-boot.bin" is a raw binary image
4686 - "u-boot" is an image in ELF binary format
4687 - "u-boot.srec" is in Motorola S-Record format
4689 By default the build is performed locally and the objects are saved
4690 in the source directory. One of the two methods can be used to change
4691 this behavior and build U-Boot to some external directory:
4693 1. Add O= to the make command line invocations:
4695 make O=/tmp/build distclean
4696 make O=/tmp/build NAME_defconfig
4697 make O=/tmp/build all
4699 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4701 export KBUILD_OUTPUT=/tmp/build
4706 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4710 Please be aware that the Makefiles assume you are using GNU make, so
4711 for instance on NetBSD you might need to use "gmake" instead of
4715 If the system board that you have is not listed, then you will need
4716 to port U-Boot to your hardware platform. To do this, follow these
4719 1. Create a new directory to hold your board specific code. Add any
4720 files you need. In your board directory, you will need at least
4721 the "Makefile" and a "<board>.c".
4722 2. Create a new configuration file "include/configs/<board>.h" for
4724 3. If you're porting U-Boot to a new CPU, then also create a new
4725 directory to hold your CPU specific code. Add any files you need.
4726 4. Run "make <board>_defconfig" with your new name.
4727 5. Type "make", and you should get a working "u-boot.srec" file
4728 to be installed on your target system.
4729 6. Debug and solve any problems that might arise.
4730 [Of course, this last step is much harder than it sounds.]
4733 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4734 ==============================================================
4736 If you have modified U-Boot sources (for instance added a new board
4737 or support for new devices, a new CPU, etc.) you are expected to
4738 provide feedback to the other developers. The feedback normally takes
4739 the form of a "patch", i. e. a context diff against a certain (latest
4740 official or latest in the git repository) version of U-Boot sources.
4742 But before you submit such a patch, please verify that your modifi-
4743 cation did not break existing code. At least make sure that *ALL* of
4744 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4745 just run the buildman script (tools/buildman/buildman), which will
4746 configure and build U-Boot for ALL supported system. Be warned, this
4747 will take a while. Please see the buildman README, or run 'buildman -H'
4751 See also "U-Boot Porting Guide" below.
4754 Monitor Commands - Overview:
4755 ============================
4757 go - start application at address 'addr'
4758 run - run commands in an environment variable
4759 bootm - boot application image from memory
4760 bootp - boot image via network using BootP/TFTP protocol
4761 bootz - boot zImage from memory
4762 tftpboot- boot image via network using TFTP protocol
4763 and env variables "ipaddr" and "serverip"
4764 (and eventually "gatewayip")
4765 tftpput - upload a file via network using TFTP protocol
4766 rarpboot- boot image via network using RARP/TFTP protocol
4767 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4768 loads - load S-Record file over serial line
4769 loadb - load binary file over serial line (kermit mode)
4771 mm - memory modify (auto-incrementing)
4772 nm - memory modify (constant address)
4773 mw - memory write (fill)
4775 cmp - memory compare
4776 crc32 - checksum calculation
4777 i2c - I2C sub-system
4778 sspi - SPI utility commands
4779 base - print or set address offset
4780 printenv- print environment variables
4781 setenv - set environment variables
4782 saveenv - save environment variables to persistent storage
4783 protect - enable or disable FLASH write protection
4784 erase - erase FLASH memory
4785 flinfo - print FLASH memory information
4786 nand - NAND memory operations (see doc/README.nand)
4787 bdinfo - print Board Info structure
4788 iminfo - print header information for application image
4789 coninfo - print console devices and informations
4790 ide - IDE sub-system
4791 loop - infinite loop on address range
4792 loopw - infinite write loop on address range
4793 mtest - simple RAM test
4794 icache - enable or disable instruction cache
4795 dcache - enable or disable data cache
4796 reset - Perform RESET of the CPU
4797 echo - echo args to console
4798 version - print monitor version
4799 help - print online help
4800 ? - alias for 'help'
4803 Monitor Commands - Detailed Description:
4804 ========================================
4808 For now: just type "help <command>".
4811 Environment Variables:
4812 ======================
4814 U-Boot supports user configuration using Environment Variables which
4815 can be made persistent by saving to Flash memory.
4817 Environment Variables are set using "setenv", printed using
4818 "printenv", and saved to Flash using "saveenv". Using "setenv"
4819 without a value can be used to delete a variable from the
4820 environment. As long as you don't save the environment you are
4821 working with an in-memory copy. In case the Flash area containing the
4822 environment is erased by accident, a default environment is provided.
4824 Some configuration options can be set using Environment Variables.
4826 List of environment variables (most likely not complete):
4828 baudrate - see CONFIG_BAUDRATE
4830 bootdelay - see CONFIG_BOOTDELAY
4832 bootcmd - see CONFIG_BOOTCOMMAND
4834 bootargs - Boot arguments when booting an RTOS image
4836 bootfile - Name of the image to load with TFTP
4838 bootm_low - Memory range available for image processing in the bootm
4839 command can be restricted. This variable is given as
4840 a hexadecimal number and defines lowest address allowed
4841 for use by the bootm command. See also "bootm_size"
4842 environment variable. Address defined by "bootm_low" is
4843 also the base of the initial memory mapping for the Linux
4844 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4847 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4848 This variable is given as a hexadecimal number and it
4849 defines the size of the memory region starting at base
4850 address bootm_low that is accessible by the Linux kernel
4851 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4852 as the default value if it is defined, and bootm_size is
4855 bootm_size - Memory range available for image processing in the bootm
4856 command can be restricted. This variable is given as
4857 a hexadecimal number and defines the size of the region
4858 allowed for use by the bootm command. See also "bootm_low"
4859 environment variable.
4861 updatefile - Location of the software update file on a TFTP server, used
4862 by the automatic software update feature. Please refer to
4863 documentation in doc/README.update for more details.
4865 autoload - if set to "no" (any string beginning with 'n'),
4866 "bootp" will just load perform a lookup of the
4867 configuration from the BOOTP server, but not try to
4868 load any image using TFTP
4870 autostart - if set to "yes", an image loaded using the "bootp",
4871 "rarpboot", "tftpboot" or "diskboot" commands will
4872 be automatically started (by internally calling
4875 If set to "no", a standalone image passed to the
4876 "bootm" command will be copied to the load address
4877 (and eventually uncompressed), but NOT be started.
4878 This can be used to load and uncompress arbitrary
4881 fdt_high - if set this restricts the maximum address that the
4882 flattened device tree will be copied into upon boot.
4883 For example, if you have a system with 1 GB memory
4884 at physical address 0x10000000, while Linux kernel
4885 only recognizes the first 704 MB as low memory, you
4886 may need to set fdt_high as 0x3C000000 to have the
4887 device tree blob be copied to the maximum address
4888 of the 704 MB low memory, so that Linux kernel can
4889 access it during the boot procedure.
4891 If this is set to the special value 0xFFFFFFFF then
4892 the fdt will not be copied at all on boot. For this
4893 to work it must reside in writable memory, have
4894 sufficient padding on the end of it for u-boot to
4895 add the information it needs into it, and the memory
4896 must be accessible by the kernel.
4898 fdtcontroladdr- if set this is the address of the control flattened
4899 device tree used by U-Boot when CONFIG_OF_CONTROL is
4902 i2cfast - (PPC405GP|PPC405EP only)
4903 if set to 'y' configures Linux I2C driver for fast
4904 mode (400kHZ). This environment variable is used in
4905 initialization code. So, for changes to be effective
4906 it must be saved and board must be reset.
4908 initrd_high - restrict positioning of initrd images:
4909 If this variable is not set, initrd images will be
4910 copied to the highest possible address in RAM; this
4911 is usually what you want since it allows for
4912 maximum initrd size. If for some reason you want to
4913 make sure that the initrd image is loaded below the
4914 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4915 variable to a value of "no" or "off" or "0".
4916 Alternatively, you can set it to a maximum upper
4917 address to use (U-Boot will still check that it
4918 does not overwrite the U-Boot stack and data).
4920 For instance, when you have a system with 16 MB
4921 RAM, and want to reserve 4 MB from use by Linux,
4922 you can do this by adding "mem=12M" to the value of
4923 the "bootargs" variable. However, now you must make
4924 sure that the initrd image is placed in the first
4925 12 MB as well - this can be done with
4927 setenv initrd_high 00c00000
4929 If you set initrd_high to 0xFFFFFFFF, this is an
4930 indication to U-Boot that all addresses are legal
4931 for the Linux kernel, including addresses in flash
4932 memory. In this case U-Boot will NOT COPY the
4933 ramdisk at all. This may be useful to reduce the
4934 boot time on your system, but requires that this
4935 feature is supported by your Linux kernel.
4937 ipaddr - IP address; needed for tftpboot command
4939 loadaddr - Default load address for commands like "bootp",
4940 "rarpboot", "tftpboot", "loadb" or "diskboot"
4942 loads_echo - see CONFIG_LOADS_ECHO
4944 serverip - TFTP server IP address; needed for tftpboot command
4946 bootretry - see CONFIG_BOOT_RETRY_TIME
4948 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4950 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4952 ethprime - controls which interface is used first.
4954 ethact - controls which interface is currently active.
4955 For example you can do the following
4957 => setenv ethact FEC
4958 => ping 192.168.0.1 # traffic sent on FEC
4959 => setenv ethact SCC
4960 => ping 10.0.0.1 # traffic sent on SCC
4962 ethrotate - When set to "no" U-Boot does not go through all
4963 available network interfaces.
4964 It just stays at the currently selected interface.
4966 netretry - When set to "no" each network operation will
4967 either succeed or fail without retrying.
4968 When set to "once" the network operation will
4969 fail when all the available network interfaces
4970 are tried once without success.
4971 Useful on scripts which control the retry operation
4974 npe_ucode - set load address for the NPE microcode
4976 silent_linux - If set then Linux will be told to boot silently, by
4977 changing the console to be empty. If "yes" it will be
4978 made silent. If "no" it will not be made silent. If
4979 unset, then it will be made silent if the U-Boot console
4982 tftpsrcp - If this is set, the value is used for TFTP's
4985 tftpdstp - If this is set, the value is used for TFTP's UDP
4986 destination port instead of the Well Know Port 69.
4988 tftpblocksize - Block size to use for TFTP transfers; if not set,
4989 we use the TFTP server's default block size
4991 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4992 seconds, minimum value is 1000 = 1 second). Defines
4993 when a packet is considered to be lost so it has to
4994 be retransmitted. The default is 5000 = 5 seconds.
4995 Lowering this value may make downloads succeed
4996 faster in networks with high packet loss rates or
4997 with unreliable TFTP servers.
4999 tftptimeoutcountmax - maximum count of TFTP timeouts (no
5000 unit, minimum value = 0). Defines how many timeouts
5001 can happen during a single file transfer before that
5002 transfer is aborted. The default is 10, and 0 means
5003 'no timeouts allowed'. Increasing this value may help
5004 downloads succeed with high packet loss rates, or with
5005 unreliable TFTP servers or client hardware.
5007 vlan - When set to a value < 4095 the traffic over
5008 Ethernet is encapsulated/received over 802.1q
5011 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5012 Unsigned value, in milliseconds. If not set, the period will
5013 be either the default (28000), or a value based on
5014 CONFIG_NET_RETRY_COUNT, if defined. This value has
5015 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5017 The following image location variables contain the location of images
5018 used in booting. The "Image" column gives the role of the image and is
5019 not an environment variable name. The other columns are environment
5020 variable names. "File Name" gives the name of the file on a TFTP
5021 server, "RAM Address" gives the location in RAM the image will be
5022 loaded to, and "Flash Location" gives the image's address in NOR
5023 flash or offset in NAND flash.
5025 *Note* - these variables don't have to be defined for all boards, some
5026 boards currently use other variables for these purposes, and some
5027 boards use these variables for other purposes.
5029 Image File Name RAM Address Flash Location
5030 ----- --------- ----------- --------------
5031 u-boot u-boot u-boot_addr_r u-boot_addr
5032 Linux kernel bootfile kernel_addr_r kernel_addr
5033 device tree blob fdtfile fdt_addr_r fdt_addr
5034 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5036 The following environment variables may be used and automatically
5037 updated by the network boot commands ("bootp" and "rarpboot"),
5038 depending the information provided by your boot server:
5040 bootfile - see above
5041 dnsip - IP address of your Domain Name Server
5042 dnsip2 - IP address of your secondary Domain Name Server
5043 gatewayip - IP address of the Gateway (Router) to use
5044 hostname - Target hostname
5046 netmask - Subnet Mask
5047 rootpath - Pathname of the root filesystem on the NFS server
5048 serverip - see above
5051 There are two special Environment Variables:
5053 serial# - contains hardware identification information such
5054 as type string and/or serial number
5055 ethaddr - Ethernet address
5057 These variables can be set only once (usually during manufacturing of
5058 the board). U-Boot refuses to delete or overwrite these variables
5059 once they have been set once.
5062 Further special Environment Variables:
5064 ver - Contains the U-Boot version string as printed
5065 with the "version" command. This variable is
5066 readonly (see CONFIG_VERSION_VARIABLE).
5069 Please note that changes to some configuration parameters may take
5070 only effect after the next boot (yes, that's just like Windoze :-).
5073 Callback functions for environment variables:
5074 ---------------------------------------------
5076 For some environment variables, the behavior of u-boot needs to change
5077 when their values are changed. This functionality allows functions to
5078 be associated with arbitrary variables. On creation, overwrite, or
5079 deletion, the callback will provide the opportunity for some side
5080 effect to happen or for the change to be rejected.
5082 The callbacks are named and associated with a function using the
5083 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5085 These callbacks are associated with variables in one of two ways. The
5086 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5087 in the board configuration to a string that defines a list of
5088 associations. The list must be in the following format:
5090 entry = variable_name[:callback_name]
5093 If the callback name is not specified, then the callback is deleted.
5094 Spaces are also allowed anywhere in the list.
5096 Callbacks can also be associated by defining the ".callbacks" variable
5097 with the same list format above. Any association in ".callbacks" will
5098 override any association in the static list. You can define
5099 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5100 ".callbacks" environment variable in the default or embedded environment.
5102 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5103 regular expression. This allows multiple variables to be connected to
5104 the same callback without explicitly listing them all out.
5107 Command Line Parsing:
5108 =====================
5110 There are two different command line parsers available with U-Boot:
5111 the old "simple" one, and the much more powerful "hush" shell:
5113 Old, simple command line parser:
5114 --------------------------------
5116 - supports environment variables (through setenv / saveenv commands)
5117 - several commands on one line, separated by ';'
5118 - variable substitution using "... ${name} ..." syntax
5119 - special characters ('$', ';') can be escaped by prefixing with '\',
5121 setenv bootcmd bootm \${address}
5122 - You can also escape text by enclosing in single apostrophes, for example:
5123 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5128 - similar to Bourne shell, with control structures like
5129 if...then...else...fi, for...do...done; while...do...done,
5130 until...do...done, ...
5131 - supports environment ("global") variables (through setenv / saveenv
5132 commands) and local shell variables (through standard shell syntax
5133 "name=value"); only environment variables can be used with "run"
5139 (1) If a command line (or an environment variable executed by a "run"
5140 command) contains several commands separated by semicolon, and
5141 one of these commands fails, then the remaining commands will be
5144 (2) If you execute several variables with one call to run (i. e.
5145 calling run with a list of variables as arguments), any failing
5146 command will cause "run" to terminate, i. e. the remaining
5147 variables are not executed.
5149 Note for Redundant Ethernet Interfaces:
5150 =======================================
5152 Some boards come with redundant Ethernet interfaces; U-Boot supports
5153 such configurations and is capable of automatic selection of a
5154 "working" interface when needed. MAC assignment works as follows:
5156 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5157 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5158 "eth1addr" (=>eth1), "eth2addr", ...
5160 If the network interface stores some valid MAC address (for instance
5161 in SROM), this is used as default address if there is NO correspon-
5162 ding setting in the environment; if the corresponding environment
5163 variable is set, this overrides the settings in the card; that means:
5165 o If the SROM has a valid MAC address, and there is no address in the
5166 environment, the SROM's address is used.
5168 o If there is no valid address in the SROM, and a definition in the
5169 environment exists, then the value from the environment variable is
5172 o If both the SROM and the environment contain a MAC address, and
5173 both addresses are the same, this MAC address is used.
5175 o If both the SROM and the environment contain a MAC address, and the
5176 addresses differ, the value from the environment is used and a
5179 o If neither SROM nor the environment contain a MAC address, an error
5180 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5181 a random, locally-assigned MAC is used.
5183 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5184 will be programmed into hardware as part of the initialization process. This
5185 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5186 The naming convention is as follows:
5187 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5192 U-Boot is capable of booting (and performing other auxiliary operations on)
5193 images in two formats:
5195 New uImage format (FIT)
5196 -----------------------
5198 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5199 to Flattened Device Tree). It allows the use of images with multiple
5200 components (several kernels, ramdisks, etc.), with contents protected by
5201 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5207 Old image format is based on binary files which can be basically anything,
5208 preceded by a special header; see the definitions in include/image.h for
5209 details; basically, the header defines the following image properties:
5211 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5212 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5213 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5214 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5216 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5217 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5218 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5219 * Compression Type (uncompressed, gzip, bzip2)
5225 The header is marked by a special Magic Number, and both the header
5226 and the data portions of the image are secured against corruption by
5233 Although U-Boot should support any OS or standalone application
5234 easily, the main focus has always been on Linux during the design of
5237 U-Boot includes many features that so far have been part of some
5238 special "boot loader" code within the Linux kernel. Also, any
5239 "initrd" images to be used are no longer part of one big Linux image;
5240 instead, kernel and "initrd" are separate images. This implementation
5241 serves several purposes:
5243 - the same features can be used for other OS or standalone
5244 applications (for instance: using compressed images to reduce the
5245 Flash memory footprint)
5247 - it becomes much easier to port new Linux kernel versions because
5248 lots of low-level, hardware dependent stuff are done by U-Boot
5250 - the same Linux kernel image can now be used with different "initrd"
5251 images; of course this also means that different kernel images can
5252 be run with the same "initrd". This makes testing easier (you don't
5253 have to build a new "zImage.initrd" Linux image when you just
5254 change a file in your "initrd"). Also, a field-upgrade of the
5255 software is easier now.
5261 Porting Linux to U-Boot based systems:
5262 ---------------------------------------
5264 U-Boot cannot save you from doing all the necessary modifications to
5265 configure the Linux device drivers for use with your target hardware
5266 (no, we don't intend to provide a full virtual machine interface to
5269 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5271 Just make sure your machine specific header file (for instance
5272 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5273 Information structure as we define in include/asm-<arch>/u-boot.h,
5274 and make sure that your definition of IMAP_ADDR uses the same value
5275 as your U-Boot configuration in CONFIG_SYS_IMMR.
5277 Note that U-Boot now has a driver model, a unified model for drivers.
5278 If you are adding a new driver, plumb it into driver model. If there
5279 is no uclass available, you are encouraged to create one. See
5283 Configuring the Linux kernel:
5284 -----------------------------
5286 No specific requirements for U-Boot. Make sure you have some root
5287 device (initial ramdisk, NFS) for your target system.
5290 Building a Linux Image:
5291 -----------------------
5293 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5294 not used. If you use recent kernel source, a new build target
5295 "uImage" will exist which automatically builds an image usable by
5296 U-Boot. Most older kernels also have support for a "pImage" target,
5297 which was introduced for our predecessor project PPCBoot and uses a
5298 100% compatible format.
5302 make TQM850L_defconfig
5307 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5308 encapsulate a compressed Linux kernel image with header information,
5309 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5311 * build a standard "vmlinux" kernel image (in ELF binary format):
5313 * convert the kernel into a raw binary image:
5315 ${CROSS_COMPILE}-objcopy -O binary \
5316 -R .note -R .comment \
5317 -S vmlinux linux.bin
5319 * compress the binary image:
5323 * package compressed binary image for U-Boot:
5325 mkimage -A ppc -O linux -T kernel -C gzip \
5326 -a 0 -e 0 -n "Linux Kernel Image" \
5327 -d linux.bin.gz uImage
5330 The "mkimage" tool can also be used to create ramdisk images for use
5331 with U-Boot, either separated from the Linux kernel image, or
5332 combined into one file. "mkimage" encapsulates the images with a 64
5333 byte header containing information about target architecture,
5334 operating system, image type, compression method, entry points, time
5335 stamp, CRC32 checksums, etc.
5337 "mkimage" can be called in two ways: to verify existing images and
5338 print the header information, or to build new images.
5340 In the first form (with "-l" option) mkimage lists the information
5341 contained in the header of an existing U-Boot image; this includes
5342 checksum verification:
5344 tools/mkimage -l image
5345 -l ==> list image header information
5347 The second form (with "-d" option) is used to build a U-Boot image
5348 from a "data file" which is used as image payload:
5350 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5351 -n name -d data_file image
5352 -A ==> set architecture to 'arch'
5353 -O ==> set operating system to 'os'
5354 -T ==> set image type to 'type'
5355 -C ==> set compression type 'comp'
5356 -a ==> set load address to 'addr' (hex)
5357 -e ==> set entry point to 'ep' (hex)
5358 -n ==> set image name to 'name'
5359 -d ==> use image data from 'datafile'
5361 Right now, all Linux kernels for PowerPC systems use the same load
5362 address (0x00000000), but the entry point address depends on the
5365 - 2.2.x kernels have the entry point at 0x0000000C,
5366 - 2.3.x and later kernels have the entry point at 0x00000000.
5368 So a typical call to build a U-Boot image would read:
5370 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5371 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5372 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5373 > examples/uImage.TQM850L
5374 Image Name: 2.4.4 kernel for TQM850L
5375 Created: Wed Jul 19 02:34:59 2000
5376 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5377 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5378 Load Address: 0x00000000
5379 Entry Point: 0x00000000
5381 To verify the contents of the image (or check for corruption):
5383 -> tools/mkimage -l examples/uImage.TQM850L
5384 Image Name: 2.4.4 kernel for TQM850L
5385 Created: Wed Jul 19 02:34:59 2000
5386 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5387 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5388 Load Address: 0x00000000
5389 Entry Point: 0x00000000
5391 NOTE: for embedded systems where boot time is critical you can trade
5392 speed for memory and install an UNCOMPRESSED image instead: this
5393 needs more space in Flash, but boots much faster since it does not
5394 need to be uncompressed:
5396 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5397 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5398 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5399 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5400 > examples/uImage.TQM850L-uncompressed
5401 Image Name: 2.4.4 kernel for TQM850L
5402 Created: Wed Jul 19 02:34:59 2000
5403 Image Type: PowerPC Linux Kernel Image (uncompressed)
5404 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5405 Load Address: 0x00000000
5406 Entry Point: 0x00000000
5409 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5410 when your kernel is intended to use an initial ramdisk:
5412 -> tools/mkimage -n 'Simple Ramdisk Image' \
5413 > -A ppc -O linux -T ramdisk -C gzip \
5414 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5415 Image Name: Simple Ramdisk Image
5416 Created: Wed Jan 12 14:01:50 2000
5417 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5418 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5419 Load Address: 0x00000000
5420 Entry Point: 0x00000000
5422 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5423 option performs the converse operation of the mkimage's second form (the "-d"
5424 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5427 tools/dumpimage -i image -T type -p position data_file
5428 -i ==> extract from the 'image' a specific 'data_file'
5429 -T ==> set image type to 'type'
5430 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5433 Installing a Linux Image:
5434 -------------------------
5436 To downloading a U-Boot image over the serial (console) interface,
5437 you must convert the image to S-Record format:
5439 objcopy -I binary -O srec examples/image examples/image.srec
5441 The 'objcopy' does not understand the information in the U-Boot
5442 image header, so the resulting S-Record file will be relative to
5443 address 0x00000000. To load it to a given address, you need to
5444 specify the target address as 'offset' parameter with the 'loads'
5447 Example: install the image to address 0x40100000 (which on the
5448 TQM8xxL is in the first Flash bank):
5450 => erase 40100000 401FFFFF
5456 ## Ready for S-Record download ...
5457 ~>examples/image.srec
5458 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5460 15989 15990 15991 15992
5461 [file transfer complete]
5463 ## Start Addr = 0x00000000
5466 You can check the success of the download using the 'iminfo' command;
5467 this includes a checksum verification so you can be sure no data
5468 corruption happened:
5472 ## Checking Image at 40100000 ...
5473 Image Name: 2.2.13 for initrd on TQM850L
5474 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5475 Data Size: 335725 Bytes = 327 kB = 0 MB
5476 Load Address: 00000000
5477 Entry Point: 0000000c
5478 Verifying Checksum ... OK
5484 The "bootm" command is used to boot an application that is stored in
5485 memory (RAM or Flash). In case of a Linux kernel image, the contents
5486 of the "bootargs" environment variable is passed to the kernel as
5487 parameters. You can check and modify this variable using the
5488 "printenv" and "setenv" commands:
5491 => printenv bootargs
5492 bootargs=root=/dev/ram
5494 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5496 => printenv bootargs
5497 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5500 ## Booting Linux kernel at 40020000 ...
5501 Image Name: 2.2.13 for NFS on TQM850L
5502 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5503 Data Size: 381681 Bytes = 372 kB = 0 MB
5504 Load Address: 00000000
5505 Entry Point: 0000000c
5506 Verifying Checksum ... OK
5507 Uncompressing Kernel Image ... OK
5508 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
5509 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5510 time_init: decrementer frequency = 187500000/60
5511 Calibrating delay loop... 49.77 BogoMIPS
5512 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5515 If you want to boot a Linux kernel with initial RAM disk, you pass
5516 the memory addresses of both the kernel and the initrd image (PPBCOOT
5517 format!) to the "bootm" command:
5519 => imi 40100000 40200000
5521 ## Checking Image at 40100000 ...
5522 Image Name: 2.2.13 for initrd on TQM850L
5523 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5524 Data Size: 335725 Bytes = 327 kB = 0 MB
5525 Load Address: 00000000
5526 Entry Point: 0000000c
5527 Verifying Checksum ... OK
5529 ## Checking Image at 40200000 ...
5530 Image Name: Simple Ramdisk Image
5531 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5532 Data Size: 566530 Bytes = 553 kB = 0 MB
5533 Load Address: 00000000
5534 Entry Point: 00000000
5535 Verifying Checksum ... OK
5537 => bootm 40100000 40200000
5538 ## Booting Linux kernel at 40100000 ...
5539 Image Name: 2.2.13 for initrd on TQM850L
5540 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5541 Data Size: 335725 Bytes = 327 kB = 0 MB
5542 Load Address: 00000000
5543 Entry Point: 0000000c
5544 Verifying Checksum ... OK
5545 Uncompressing Kernel Image ... OK
5546 ## Loading RAMDisk Image at 40200000 ...
5547 Image Name: Simple Ramdisk Image
5548 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5549 Data Size: 566530 Bytes = 553 kB = 0 MB
5550 Load Address: 00000000
5551 Entry Point: 00000000
5552 Verifying Checksum ... OK
5553 Loading Ramdisk ... OK
5554 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
5555 Boot arguments: root=/dev/ram
5556 time_init: decrementer frequency = 187500000/60
5557 Calibrating delay loop... 49.77 BogoMIPS
5559 RAMDISK: Compressed image found at block 0
5560 VFS: Mounted root (ext2 filesystem).
5564 Boot Linux and pass a flat device tree:
5567 First, U-Boot must be compiled with the appropriate defines. See the section
5568 titled "Linux Kernel Interface" above for a more in depth explanation. The
5569 following is an example of how to start a kernel and pass an updated
5575 oft=oftrees/mpc8540ads.dtb
5576 => tftp $oftaddr $oft
5577 Speed: 1000, full duplex
5579 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5580 Filename 'oftrees/mpc8540ads.dtb'.
5581 Load address: 0x300000
5584 Bytes transferred = 4106 (100a hex)
5585 => tftp $loadaddr $bootfile
5586 Speed: 1000, full duplex
5588 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5590 Load address: 0x200000
5591 Loading:############
5593 Bytes transferred = 1029407 (fb51f hex)
5598 => bootm $loadaddr - $oftaddr
5599 ## Booting image at 00200000 ...
5600 Image Name: Linux-2.6.17-dirty
5601 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5602 Data Size: 1029343 Bytes = 1005.2 kB
5603 Load Address: 00000000
5604 Entry Point: 00000000
5605 Verifying Checksum ... OK
5606 Uncompressing Kernel Image ... OK
5607 Booting using flat device tree at 0x300000
5608 Using MPC85xx ADS machine description
5609 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5613 More About U-Boot Image Types:
5614 ------------------------------
5616 U-Boot supports the following image types:
5618 "Standalone Programs" are directly runnable in the environment
5619 provided by U-Boot; it is expected that (if they behave
5620 well) you can continue to work in U-Boot after return from
5621 the Standalone Program.
5622 "OS Kernel Images" are usually images of some Embedded OS which
5623 will take over control completely. Usually these programs
5624 will install their own set of exception handlers, device
5625 drivers, set up the MMU, etc. - this means, that you cannot
5626 expect to re-enter U-Boot except by resetting the CPU.
5627 "RAMDisk Images" are more or less just data blocks, and their
5628 parameters (address, size) are passed to an OS kernel that is
5630 "Multi-File Images" contain several images, typically an OS
5631 (Linux) kernel image and one or more data images like
5632 RAMDisks. This construct is useful for instance when you want
5633 to boot over the network using BOOTP etc., where the boot
5634 server provides just a single image file, but you want to get
5635 for instance an OS kernel and a RAMDisk image.
5637 "Multi-File Images" start with a list of image sizes, each
5638 image size (in bytes) specified by an "uint32_t" in network
5639 byte order. This list is terminated by an "(uint32_t)0".
5640 Immediately after the terminating 0 follow the images, one by
5641 one, all aligned on "uint32_t" boundaries (size rounded up to
5642 a multiple of 4 bytes).
5644 "Firmware Images" are binary images containing firmware (like
5645 U-Boot or FPGA images) which usually will be programmed to
5648 "Script files" are command sequences that will be executed by
5649 U-Boot's command interpreter; this feature is especially
5650 useful when you configure U-Boot to use a real shell (hush)
5651 as command interpreter.
5653 Booting the Linux zImage:
5654 -------------------------
5656 On some platforms, it's possible to boot Linux zImage. This is done
5657 using the "bootz" command. The syntax of "bootz" command is the same
5658 as the syntax of "bootm" command.
5660 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5661 kernel with raw initrd images. The syntax is slightly different, the
5662 address of the initrd must be augmented by it's size, in the following
5663 format: "<initrd addres>:<initrd size>".
5669 One of the features of U-Boot is that you can dynamically load and
5670 run "standalone" applications, which can use some resources of
5671 U-Boot like console I/O functions or interrupt services.
5673 Two simple examples are included with the sources:
5678 'examples/hello_world.c' contains a small "Hello World" Demo
5679 application; it is automatically compiled when you build U-Boot.
5680 It's configured to run at address 0x00040004, so you can play with it
5684 ## Ready for S-Record download ...
5685 ~>examples/hello_world.srec
5686 1 2 3 4 5 6 7 8 9 10 11 ...
5687 [file transfer complete]
5689 ## Start Addr = 0x00040004
5691 => go 40004 Hello World! This is a test.
5692 ## Starting application at 0x00040004 ...
5703 Hit any key to exit ...
5705 ## Application terminated, rc = 0x0
5707 Another example, which demonstrates how to register a CPM interrupt
5708 handler with the U-Boot code, can be found in 'examples/timer.c'.
5709 Here, a CPM timer is set up to generate an interrupt every second.
5710 The interrupt service routine is trivial, just printing a '.'
5711 character, but this is just a demo program. The application can be
5712 controlled by the following keys:
5714 ? - print current values og the CPM Timer registers
5715 b - enable interrupts and start timer
5716 e - stop timer and disable interrupts
5717 q - quit application
5720 ## Ready for S-Record download ...
5721 ~>examples/timer.srec
5722 1 2 3 4 5 6 7 8 9 10 11 ...
5723 [file transfer complete]
5725 ## Start Addr = 0x00040004
5728 ## Starting application at 0x00040004 ...
5731 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5734 [q, b, e, ?] Set interval 1000000 us
5737 [q, b, e, ?] ........
5738 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5741 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5744 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5747 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5749 [q, b, e, ?] ...Stopping timer
5751 [q, b, e, ?] ## Application terminated, rc = 0x0
5757 Over time, many people have reported problems when trying to use the
5758 "minicom" terminal emulation program for serial download. I (wd)
5759 consider minicom to be broken, and recommend not to use it. Under
5760 Unix, I recommend to use C-Kermit for general purpose use (and
5761 especially for kermit binary protocol download ("loadb" command), and
5762 use "cu" for S-Record download ("loads" command). See
5763 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5764 for help with kermit.
5767 Nevertheless, if you absolutely want to use it try adding this
5768 configuration to your "File transfer protocols" section:
5770 Name Program Name U/D FullScr IO-Red. Multi
5771 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5772 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5778 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5779 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5781 Building requires a cross environment; it is known to work on
5782 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5783 need gmake since the Makefiles are not compatible with BSD make).
5784 Note that the cross-powerpc package does not install include files;
5785 attempting to build U-Boot will fail because <machine/ansi.h> is
5786 missing. This file has to be installed and patched manually:
5788 # cd /usr/pkg/cross/powerpc-netbsd/include
5790 # ln -s powerpc machine
5791 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5792 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5794 Native builds *don't* work due to incompatibilities between native
5795 and U-Boot include files.
5797 Booting assumes that (the first part of) the image booted is a
5798 stage-2 loader which in turn loads and then invokes the kernel
5799 proper. Loader sources will eventually appear in the NetBSD source
5800 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5801 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5804 Implementation Internals:
5805 =========================
5807 The following is not intended to be a complete description of every
5808 implementation detail. However, it should help to understand the
5809 inner workings of U-Boot and make it easier to port it to custom
5813 Initial Stack, Global Data:
5814 ---------------------------
5816 The implementation of U-Boot is complicated by the fact that U-Boot
5817 starts running out of ROM (flash memory), usually without access to
5818 system RAM (because the memory controller is not initialized yet).
5819 This means that we don't have writable Data or BSS segments, and BSS
5820 is not initialized as zero. To be able to get a C environment working
5821 at all, we have to allocate at least a minimal stack. Implementation
5822 options for this are defined and restricted by the CPU used: Some CPU
5823 models provide on-chip memory (like the IMMR area on MPC8xx and
5824 MPC826x processors), on others (parts of) the data cache can be
5825 locked as (mis-) used as memory, etc.
5827 Chris Hallinan posted a good summary of these issues to the
5828 U-Boot mailing list:
5830 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5831 From: "Chris Hallinan" <clh@net1plus.com>
5832 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5835 Correct me if I'm wrong, folks, but the way I understand it
5836 is this: Using DCACHE as initial RAM for Stack, etc, does not
5837 require any physical RAM backing up the cache. The cleverness
5838 is that the cache is being used as a temporary supply of
5839 necessary storage before the SDRAM controller is setup. It's
5840 beyond the scope of this list to explain the details, but you
5841 can see how this works by studying the cache architecture and
5842 operation in the architecture and processor-specific manuals.
5844 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5845 is another option for the system designer to use as an
5846 initial stack/RAM area prior to SDRAM being available. Either
5847 option should work for you. Using CS 4 should be fine if your
5848 board designers haven't used it for something that would
5849 cause you grief during the initial boot! It is frequently not
5852 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5853 with your processor/board/system design. The default value
5854 you will find in any recent u-boot distribution in
5855 walnut.h should work for you. I'd set it to a value larger
5856 than your SDRAM module. If you have a 64MB SDRAM module, set
5857 it above 400_0000. Just make sure your board has no resources
5858 that are supposed to respond to that address! That code in
5859 start.S has been around a while and should work as is when
5860 you get the config right.
5865 It is essential to remember this, since it has some impact on the C
5866 code for the initialization procedures:
5868 * Initialized global data (data segment) is read-only. Do not attempt
5871 * Do not use any uninitialized global data (or implicitly initialized
5872 as zero data - BSS segment) at all - this is undefined, initiali-
5873 zation is performed later (when relocating to RAM).
5875 * Stack space is very limited. Avoid big data buffers or things like
5878 Having only the stack as writable memory limits means we cannot use
5879 normal global data to share information between the code. But it
5880 turned out that the implementation of U-Boot can be greatly
5881 simplified by making a global data structure (gd_t) available to all
5882 functions. We could pass a pointer to this data as argument to _all_
5883 functions, but this would bloat the code. Instead we use a feature of
5884 the GCC compiler (Global Register Variables) to share the data: we
5885 place a pointer (gd) to the global data into a register which we
5886 reserve for this purpose.
5888 When choosing a register for such a purpose we are restricted by the
5889 relevant (E)ABI specifications for the current architecture, and by
5890 GCC's implementation.
5892 For PowerPC, the following registers have specific use:
5894 R2: reserved for system use
5895 R3-R4: parameter passing and return values
5896 R5-R10: parameter passing
5897 R13: small data area pointer
5901 (U-Boot also uses R12 as internal GOT pointer. r12
5902 is a volatile register so r12 needs to be reset when
5903 going back and forth between asm and C)
5905 ==> U-Boot will use R2 to hold a pointer to the global data
5907 Note: on PPC, we could use a static initializer (since the
5908 address of the global data structure is known at compile time),
5909 but it turned out that reserving a register results in somewhat
5910 smaller code - although the code savings are not that big (on
5911 average for all boards 752 bytes for the whole U-Boot image,
5912 624 text + 127 data).
5914 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5915 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5917 ==> U-Boot will use P3 to hold a pointer to the global data
5919 On ARM, the following registers are used:
5921 R0: function argument word/integer result
5922 R1-R3: function argument word
5923 R9: platform specific
5924 R10: stack limit (used only if stack checking is enabled)
5925 R11: argument (frame) pointer
5926 R12: temporary workspace
5929 R15: program counter
5931 ==> U-Boot will use R9 to hold a pointer to the global data
5933 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5935 On Nios II, the ABI is documented here:
5936 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5938 ==> U-Boot will use gp to hold a pointer to the global data
5940 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5941 to access small data sections, so gp is free.
5943 On NDS32, the following registers are used:
5945 R0-R1: argument/return
5947 R15: temporary register for assembler
5948 R16: trampoline register
5949 R28: frame pointer (FP)
5950 R29: global pointer (GP)
5951 R30: link register (LP)
5952 R31: stack pointer (SP)
5953 PC: program counter (PC)
5955 ==> U-Boot will use R10 to hold a pointer to the global data
5957 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5958 or current versions of GCC may "optimize" the code too much.
5963 U-Boot runs in system state and uses physical addresses, i.e. the
5964 MMU is not used either for address mapping nor for memory protection.
5966 The available memory is mapped to fixed addresses using the memory
5967 controller. In this process, a contiguous block is formed for each
5968 memory type (Flash, SDRAM, SRAM), even when it consists of several
5969 physical memory banks.
5971 U-Boot is installed in the first 128 kB of the first Flash bank (on
5972 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5973 booting and sizing and initializing DRAM, the code relocates itself
5974 to the upper end of DRAM. Immediately below the U-Boot code some
5975 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5976 configuration setting]. Below that, a structure with global Board
5977 Info data is placed, followed by the stack (growing downward).
5979 Additionally, some exception handler code is copied to the low 8 kB
5980 of DRAM (0x00000000 ... 0x00001FFF).
5982 So a typical memory configuration with 16 MB of DRAM could look like
5985 0x0000 0000 Exception Vector code
5988 0x0000 2000 Free for Application Use
5994 0x00FB FF20 Monitor Stack (Growing downward)
5995 0x00FB FFAC Board Info Data and permanent copy of global data
5996 0x00FC 0000 Malloc Arena
5999 0x00FE 0000 RAM Copy of Monitor Code
6000 ... eventually: LCD or video framebuffer
6001 ... eventually: pRAM (Protected RAM - unchanged by reset)
6002 0x00FF FFFF [End of RAM]
6005 System Initialization:
6006 ----------------------
6008 In the reset configuration, U-Boot starts at the reset entry point
6009 (on most PowerPC systems at address 0x00000100). Because of the reset
6010 configuration for CS0# this is a mirror of the on board Flash memory.
6011 To be able to re-map memory U-Boot then jumps to its link address.
6012 To be able to implement the initialization code in C, a (small!)
6013 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6014 which provide such a feature like MPC8xx or MPC8260), or in a locked
6015 part of the data cache. After that, U-Boot initializes the CPU core,
6016 the caches and the SIU.
6018 Next, all (potentially) available memory banks are mapped using a
6019 preliminary mapping. For example, we put them on 512 MB boundaries
6020 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6021 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6022 programmed for SDRAM access. Using the temporary configuration, a
6023 simple memory test is run that determines the size of the SDRAM
6026 When there is more than one SDRAM bank, and the banks are of
6027 different size, the largest is mapped first. For equal size, the first
6028 bank (CS2#) is mapped first. The first mapping is always for address
6029 0x00000000, with any additional banks following immediately to create
6030 contiguous memory starting from 0.
6032 Then, the monitor installs itself at the upper end of the SDRAM area
6033 and allocates memory for use by malloc() and for the global Board
6034 Info data; also, the exception vector code is copied to the low RAM
6035 pages, and the final stack is set up.
6037 Only after this relocation will you have a "normal" C environment;
6038 until that you are restricted in several ways, mostly because you are
6039 running from ROM, and because the code will have to be relocated to a
6043 U-Boot Porting Guide:
6044 ----------------------
6046 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6050 int main(int argc, char *argv[])
6052 sighandler_t no_more_time;
6054 signal(SIGALRM, no_more_time);
6055 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6057 if (available_money > available_manpower) {
6058 Pay consultant to port U-Boot;
6062 Download latest U-Boot source;
6064 Subscribe to u-boot mailing list;
6067 email("Hi, I am new to U-Boot, how do I get started?");
6070 Read the README file in the top level directory;
6071 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6072 Read applicable doc/*.README;
6073 Read the source, Luke;
6074 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6077 if (available_money > toLocalCurrency ($2500))
6080 Add a lot of aggravation and time;
6082 if (a similar board exists) { /* hopefully... */
6083 cp -a board/<similar> board/<myboard>
6084 cp include/configs/<similar>.h include/configs/<myboard>.h
6086 Create your own board support subdirectory;
6087 Create your own board include/configs/<myboard>.h file;
6089 Edit new board/<myboard> files
6090 Edit new include/configs/<myboard>.h
6095 Add / modify source code;
6099 email("Hi, I am having problems...");
6101 Send patch file to the U-Boot email list;
6102 if (reasonable critiques)
6103 Incorporate improvements from email list code review;
6105 Defend code as written;
6111 void no_more_time (int sig)
6120 All contributions to U-Boot should conform to the Linux kernel
6121 coding style; see the file "Documentation/CodingStyle" and the script
6122 "scripts/Lindent" in your Linux kernel source directory.
6124 Source files originating from a different project (for example the
6125 MTD subsystem) are generally exempt from these guidelines and are not
6126 reformatted to ease subsequent migration to newer versions of those
6129 Please note that U-Boot is implemented in C (and to some small parts in
6130 Assembler); no C++ is used, so please do not use C++ style comments (//)
6133 Please also stick to the following formatting rules:
6134 - remove any trailing white space
6135 - use TAB characters for indentation and vertical alignment, not spaces
6136 - make sure NOT to use DOS '\r\n' line feeds
6137 - do not add more than 2 consecutive empty lines to source files
6138 - do not add trailing empty lines to source files
6140 Submissions which do not conform to the standards may be returned
6141 with a request to reformat the changes.
6147 Since the number of patches for U-Boot is growing, we need to
6148 establish some rules. Submissions which do not conform to these rules
6149 may be rejected, even when they contain important and valuable stuff.
6151 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6153 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6154 see http://lists.denx.de/mailman/listinfo/u-boot
6156 When you send a patch, please include the following information with
6159 * For bug fixes: a description of the bug and how your patch fixes
6160 this bug. Please try to include a way of demonstrating that the
6161 patch actually fixes something.
6163 * For new features: a description of the feature and your
6166 * A CHANGELOG entry as plaintext (separate from the patch)
6168 * For major contributions, add a MAINTAINERS file with your
6169 information and associated file and directory references.
6171 * When you add support for a new board, don't forget to add a
6172 maintainer e-mail address to the boards.cfg file, too.
6174 * If your patch adds new configuration options, don't forget to
6175 document these in the README file.
6177 * The patch itself. If you are using git (which is *strongly*
6178 recommended) you can easily generate the patch using the
6179 "git format-patch". If you then use "git send-email" to send it to
6180 the U-Boot mailing list, you will avoid most of the common problems
6181 with some other mail clients.
6183 If you cannot use git, use "diff -purN OLD NEW". If your version of
6184 diff does not support these options, then get the latest version of
6187 The current directory when running this command shall be the parent
6188 directory of the U-Boot source tree (i. e. please make sure that
6189 your patch includes sufficient directory information for the
6192 We prefer patches as plain text. MIME attachments are discouraged,
6193 and compressed attachments must not be used.
6195 * If one logical set of modifications affects or creates several
6196 files, all these changes shall be submitted in a SINGLE patch file.
6198 * Changesets that contain different, unrelated modifications shall be
6199 submitted as SEPARATE patches, one patch per changeset.
6204 * Before sending the patch, run the buildman script on your patched
6205 source tree and make sure that no errors or warnings are reported
6206 for any of the boards.
6208 * Keep your modifications to the necessary minimum: A patch
6209 containing several unrelated changes or arbitrary reformats will be
6210 returned with a request to re-formatting / split it.
6212 * If you modify existing code, make sure that your new code does not
6213 add to the memory footprint of the code ;-) Small is beautiful!
6214 When adding new features, these should compile conditionally only
6215 (using #ifdef), and the resulting code with the new feature
6216 disabled must not need more memory than the old code without your
6219 * Remember that there is a size limit of 100 kB per message on the
6220 u-boot mailing list. Bigger patches will be moderated. If they are
6221 reasonable and not too big, they will be acknowledged. But patches
6222 bigger than the size limit should be avoided.
projects / u-boot / blob