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 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
317 The following options need to be configured:
319 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
321 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
323 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
324 Define exactly one, e.g. CONFIG_ATSTK1002
326 - Marvell Family Member
327 CONFIG_SYS_MVFS - define it if you want to enable
328 multiple fs option at one time
329 for marvell soc family
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
362 Specifies that the core is a 64-bit PowerPC implementation (implements
363 the "64" category of the Power ISA). This is necessary for ePAPR
364 compliance, among other possible reasons.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_FSL_ERRATUM_A004510
379 Enables a workaround for erratum A004510. If set,
380 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
381 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
383 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
386 Defines one or two SoC revisions (low 8 bits of SVR)
387 for which the A004510 workaround should be applied.
389 The rest of SVR is either not relevant to the decision
390 of whether the erratum is present (e.g. p2040 versus
391 p2041) or is implied by the build target, which controls
392 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
394 See Freescale App Note 4493 for more information about
397 CONFIG_A003399_NOR_WORKAROUND
398 Enables a workaround for IFC erratum A003399. It is only
399 required during NOR boot.
401 CONFIG_A008044_WORKAROUND
402 Enables a workaround for T1040/T1042 erratum A008044. It is only
403 required during NAND boot and valid for Rev 1.0 SoC revision
405 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407 This is the value to write into CCSR offset 0x18600
408 according to the A004510 workaround.
410 CONFIG_SYS_FSL_DSP_DDR_ADDR
411 This value denotes start offset of DDR memory which is
412 connected exclusively to the DSP cores.
414 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
415 This value denotes start offset of M2 memory
416 which is directly connected to the DSP core.
418 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
419 This value denotes start offset of M3 memory which is directly
420 connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
423 This value denotes start offset of DSP CCSR space.
425 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
426 Single Source Clock is clocking mode present in some of FSL SoC's.
427 In this mode, a single differential clock is used to supply
428 clocks to the sysclock, ddrclock and usbclock.
430 CONFIG_SYS_CPC_REINIT_F
431 This CONFIG is defined when the CPC is configured as SRAM at the
432 time of U-Boot entry and is required to be re-initialized.
435 Indicates this SoC supports deep sleep feature. If deep sleep is
436 supported, core will start to execute uboot when wakes up.
438 - Generic CPU options:
439 CONFIG_SYS_GENERIC_GLOBAL_DATA
440 Defines global data is initialized in generic board board_init_f().
441 If this macro is defined, global data is created and cleared in
442 generic board board_init_f(). Without this macro, architecture/board
443 should initialize global data before calling board_init_f().
445 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
447 Defines the endianess of the CPU. Implementation of those
448 values is arch specific.
451 Freescale DDR driver in use. This type of DDR controller is
452 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
455 CONFIG_SYS_FSL_DDR_ADDR
456 Freescale DDR memory-mapped register base.
458 CONFIG_SYS_FSL_DDR_EMU
459 Specify emulator support for DDR. Some DDR features such as
460 deskew training are not available.
462 CONFIG_SYS_FSL_DDRC_GEN1
463 Freescale DDR1 controller.
465 CONFIG_SYS_FSL_DDRC_GEN2
466 Freescale DDR2 controller.
468 CONFIG_SYS_FSL_DDRC_GEN3
469 Freescale DDR3 controller.
471 CONFIG_SYS_FSL_DDRC_GEN4
472 Freescale DDR4 controller.
474 CONFIG_SYS_FSL_DDRC_ARM_GEN3
475 Freescale DDR3 controller for ARM-based SoCs.
478 Board config to use DDR1. It can be enabled for SoCs with
479 Freescale DDR1 or DDR2 controllers, depending on the board
483 Board config to use DDR2. It can be enabled for SoCs with
484 Freescale DDR2 or DDR3 controllers, depending on the board
488 Board config to use DDR3. It can be enabled for SoCs with
489 Freescale DDR3 or DDR3L controllers.
492 Board config to use DDR3L. It can be enabled for SoCs with
496 Board config to use DDR4. It can be enabled for SoCs with
499 CONFIG_SYS_FSL_IFC_BE
500 Defines the IFC controller register space as Big Endian
502 CONFIG_SYS_FSL_IFC_LE
503 Defines the IFC controller register space as Little Endian
505 CONFIG_SYS_FSL_IFC_CLK_DIV
506 Defines divider of platform clock(clock input to IFC controller).
508 CONFIG_SYS_FSL_LBC_CLK_DIV
509 Defines divider of platform clock(clock input to eLBC controller).
511 CONFIG_SYS_FSL_PBL_PBI
512 It enables addition of RCW (Power on reset configuration) in built image.
513 Please refer doc/README.pblimage for more details
515 CONFIG_SYS_FSL_PBL_RCW
516 It adds PBI(pre-boot instructions) commands in u-boot build image.
517 PBI commands can be used to configure SoC before it starts the execution.
518 Please refer doc/README.pblimage for more details
521 It adds a target to create boot binary having SPL binary in PBI format
522 concatenated with u-boot binary.
524 CONFIG_SYS_FSL_DDR_BE
525 Defines the DDR controller register space as Big Endian
527 CONFIG_SYS_FSL_DDR_LE
528 Defines the DDR controller register space as Little Endian
530 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
531 Physical address from the view of DDR controllers. It is the
532 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
533 it could be different for ARM SoCs.
535 CONFIG_SYS_FSL_DDR_INTLV_256B
536 DDR controller interleaving on 256-byte. This is a special
537 interleaving mode, handled by Dickens for Freescale layerscape
540 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
541 Number of controllers used as main memory.
543 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
544 Number of controllers used for other than main memory.
546 CONFIG_SYS_FSL_HAS_DP_DDR
547 Defines the SoC has DP-DDR used for DPAA.
549 CONFIG_SYS_FSL_SEC_BE
550 Defines the SEC controller register space as Big Endian
552 CONFIG_SYS_FSL_SEC_LE
553 Defines the SEC controller register space as Little Endian
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
594 Generic timer clock source frequency.
596 COUNTER_FREQUENCY_REAL
597 Generic timer clock source frequency if the real clock is
598 different from COUNTER_FREQUENCY, and can only be determined
602 CONFIG_TEGRA_SUPPORT_NON_SECURE
604 Support executing U-Boot in non-secure (NS) mode. Certain
605 impossible actions will be skipped if the CPU is in NS mode,
606 such as ARM architectural timer initialization.
608 - Linux Kernel Interface:
611 U-Boot stores all clock information in Hz
612 internally. For binary compatibility with older Linux
613 kernels (which expect the clocks passed in the
614 bd_info data to be in MHz) the environment variable
615 "clocks_in_mhz" can be defined so that U-Boot
616 converts clock data to MHZ before passing it to the
618 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
619 "clocks_in_mhz=1" is automatically included in the
622 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
624 When transferring memsize parameter to Linux, some versions
625 expect it to be in bytes, others in MB.
626 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
630 New kernel versions are expecting firmware settings to be
631 passed using flattened device trees (based on open firmware
635 * New libfdt-based support
636 * Adds the "fdt" command
637 * The bootm command automatically updates the fdt
639 OF_CPU - The proper name of the cpus node (only required for
640 MPC512X and MPC5xxx based boards).
641 OF_SOC - The proper name of the soc node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_TBCLK - The timebase frequency.
644 OF_STDOUT_PATH - The path to the console device
646 boards with QUICC Engines require OF_QE to set UCC MAC
649 CONFIG_OF_BOARD_SETUP
651 Board code has addition modification that it wants to make
652 to the flat device tree before handing it off to the kernel
654 CONFIG_OF_SYSTEM_SETUP
656 Other code has addition modification that it wants to make
657 to the flat device tree before handing it off to the kernel.
658 This causes ft_system_setup() to be called before booting
663 U-Boot can detect if an IDE device is present or not.
664 If not, and this new config option is activated, U-Boot
665 removes the ATA node from the DTS before booting Linux,
666 so the Linux IDE driver does not probe the device and
667 crash. This is needed for buggy hardware (uc101) where
668 no pull down resistor is connected to the signal IDE5V_DD7.
670 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
672 This setting is mandatory for all boards that have only one
673 machine type and must be used to specify the machine type
674 number as it appears in the ARM machine registry
675 (see http://www.arm.linux.org.uk/developer/machines/).
676 Only boards that have multiple machine types supported
677 in a single configuration file and the machine type is
678 runtime discoverable, do not have to use this setting.
680 - vxWorks boot parameters:
682 bootvx constructs a valid bootline using the following
683 environments variables: bootdev, bootfile, ipaddr, netmask,
684 serverip, gatewayip, hostname, othbootargs.
685 It loads the vxWorks image pointed bootfile.
687 Note: If a "bootargs" environment is defined, it will overwride
688 the defaults discussed just above.
690 - Cache Configuration:
691 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
692 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
693 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
695 - Cache Configuration for ARM:
696 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
698 CONFIG_SYS_PL310_BASE - Physical base address of PL310
699 controller register space
704 Define this if you want support for Amba PrimeCell PL010 UARTs.
708 Define this if you want support for Amba PrimeCell PL011 UARTs.
712 If you have Amba PrimeCell PL011 UARTs, set this variable to
713 the clock speed of the UARTs.
717 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
718 define this to a list of base addresses for each (supported)
719 port. See e.g. include/configs/versatile.h
721 CONFIG_SERIAL_HW_FLOW_CONTROL
723 Define this variable to enable hw flow control in serial driver.
724 Current user of this option is drivers/serial/nsl16550.c driver
727 Depending on board, define exactly one serial port
728 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
729 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
730 console by defining CONFIG_8xx_CONS_NONE
732 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
733 port routines must be defined elsewhere
734 (i.e. serial_init(), serial_getc(), ...)
737 CONFIG_BAUDRATE - in bps
738 Select one of the baudrates listed in
739 CONFIG_SYS_BAUDRATE_TABLE, see below.
740 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
742 - Console Rx buffer length
743 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
744 the maximum receive buffer length for the SMC.
745 This option is actual only for 82xx and 8xx possible.
746 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
747 must be defined, to setup the maximum idle timeout for
752 Only needed when CONFIG_BOOTDELAY is enabled;
753 define a command string that is automatically executed
754 when no character is read on the console interface
755 within "Boot Delay" after reset.
758 This can be used to pass arguments to the bootm
759 command. The value of CONFIG_BOOTARGS goes into the
760 environment value "bootargs".
762 CONFIG_RAMBOOT and CONFIG_NFSBOOT
763 The value of these goes into the environment as
764 "ramboot" and "nfsboot" respectively, and can be used
765 as a convenience, when switching between booting from
769 CONFIG_BOOTCOUNT_LIMIT
770 Implements a mechanism for detecting a repeating reboot
772 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
775 If no softreset save registers are found on the hardware
776 "bootcount" is stored in the environment. To prevent a
777 saveenv on all reboots, the environment variable
778 "upgrade_available" is used. If "upgrade_available" is
779 0, "bootcount" is always 0, if "upgrade_available" is
780 1 "bootcount" is incremented in the environment.
781 So the Userspace Applikation must set the "upgrade_available"
782 and "bootcount" variable to 0, if a boot was successfully.
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or adding #define's for wanted commands.
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
824 CONFIG_CMD_ASKENV * ask for env variable
825 CONFIG_CMD_BDI bdinfo
826 CONFIG_CMD_BOOTD bootd
827 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
828 CONFIG_CMD_CACHE * icache, dcache
829 CONFIG_CMD_CONSOLE coninfo
830 CONFIG_CMD_CRC32 * crc32
831 CONFIG_CMD_DHCP * DHCP support
832 CONFIG_CMD_DIAG * Diagnostics
833 CONFIG_CMD_DTT * Digital Therm and Thermostat
834 CONFIG_CMD_ECHO echo arguments
835 CONFIG_CMD_EDITENV edit env variable
836 CONFIG_CMD_EEPROM * EEPROM read/write support
837 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
838 CONFIG_CMD_ELF * bootelf, bootvx
839 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
840 CONFIG_CMD_ENV_FLAGS * display details about env flags
841 CONFIG_CMD_ENV_EXISTS * check existence of env variable
842 CONFIG_CMD_EXPORTENV * export the environment
843 CONFIG_CMD_EXT2 * ext2 command support
844 CONFIG_CMD_EXT4 * ext4 command support
845 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
846 that work for multiple fs types
847 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
848 CONFIG_CMD_SAVEENV saveenv
849 CONFIG_CMD_FDC * Floppy Disk Support
850 CONFIG_CMD_FAT * FAT command support
851 CONFIG_CMD_FLASH flinfo, erase, protect
852 CONFIG_CMD_FPGA FPGA device initialization support
853 CONFIG_CMD_FUSE * Device fuse support
854 CONFIG_CMD_GETTIME * Get time since boot
855 CONFIG_CMD_GO * the 'go' command (exec code)
856 CONFIG_CMD_GREPENV * search environment
857 CONFIG_CMD_HASH * calculate hash / digest
858 CONFIG_CMD_I2C * I2C serial bus support
859 CONFIG_CMD_IDE * IDE harddisk support
860 CONFIG_CMD_IMI iminfo
861 CONFIG_CMD_IMLS List all images found in NOR flash
862 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
863 CONFIG_CMD_IMMAP * IMMR dump support
864 CONFIG_CMD_IOTRACE * I/O tracing for debugging
865 CONFIG_CMD_IMPORTENV * import an environment
866 CONFIG_CMD_INI * import data from an ini file into the env
867 CONFIG_CMD_IRQ * irqinfo
868 CONFIG_CMD_ITEST Integer/string test of 2 values
869 CONFIG_CMD_JFFS2 * JFFS2 Support
870 CONFIG_CMD_KGDB * kgdb
871 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
872 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
874 CONFIG_CMD_LOADB loadb
875 CONFIG_CMD_LOADS loads
876 CONFIG_CMD_MD5SUM * print md5 message digest
877 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
878 CONFIG_CMD_MEMINFO * Display detailed memory information
879 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
881 CONFIG_CMD_MEMTEST * mtest
882 CONFIG_CMD_MISC Misc functions like sleep etc
883 CONFIG_CMD_MMC * MMC memory mapped support
884 CONFIG_CMD_MII * MII utility commands
885 CONFIG_CMD_MTDPARTS * MTD partition support
886 CONFIG_CMD_NAND * NAND support
887 CONFIG_CMD_NET bootp, tftpboot, rarpboot
888 CONFIG_CMD_NFS NFS support
889 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
890 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
891 CONFIG_CMD_PCI * pciinfo
892 CONFIG_CMD_PCMCIA * PCMCIA support
893 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
895 CONFIG_CMD_PORTIO * Port I/O
896 CONFIG_CMD_READ * Read raw data from partition
897 CONFIG_CMD_REGINFO * Register dump
898 CONFIG_CMD_RUN run command in env variable
899 CONFIG_CMD_SANDBOX * sb command to access sandbox features
900 CONFIG_CMD_SAVES * save S record dump
901 CONFIG_SCSI * SCSI Support
902 CONFIG_CMD_SDRAM * print SDRAM configuration information
903 (requires CONFIG_CMD_I2C)
904 CONFIG_CMD_SETGETDCR Support for DCR Register access
906 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
907 CONFIG_CMD_SHA1SUM * print sha1 memory digest
908 (requires CONFIG_CMD_MEMORY)
909 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
910 CONFIG_CMD_SOURCE "source" command Support
911 CONFIG_CMD_SPI * SPI serial bus support
912 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
913 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
914 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
915 CONFIG_CMD_TIMER * access to the system tick timer
916 CONFIG_CMD_USB * USB support
917 CONFIG_CMD_CDP * Cisco Discover Protocol support
918 CONFIG_CMD_MFSL * Microblaze FSL support
919 CONFIG_CMD_XIMG Load part of Multi Image
920 CONFIG_CMD_UUID * Generate random UUID or GUID string
922 EXAMPLE: If you want all functions except of network
923 support you can write:
925 #include "config_cmd_all.h"
926 #undef CONFIG_CMD_NET
929 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
931 Note: Don't enable the "icache" and "dcache" commands
932 (configuration option CONFIG_CMD_CACHE) unless you know
933 what you (and your U-Boot users) are doing. Data
934 cache cannot be enabled on systems like the 8xx or
935 8260 (where accesses to the IMMR region must be
936 uncached), and it cannot be disabled on all other
937 systems where we (mis-) use the data cache to hold an
938 initial stack and some data.
941 XXX - this list needs to get updated!
943 - Removal of commands
944 If no commands are needed to boot, you can disable
945 CONFIG_CMDLINE to remove them. In this case, the command line
946 will not be available, and when U-Boot wants to execute the
947 boot command (on start-up) it will call board_run_command()
948 instead. This can reduce image size significantly for very
949 simple boot procedures.
951 - Regular expression support:
953 If this variable is defined, U-Boot is linked against
954 the SLRE (Super Light Regular Expression) library,
955 which adds regex support to some commands, as for
956 example "env grep" and "setexpr".
960 If this variable is defined, U-Boot will use a device tree
961 to configure its devices, instead of relying on statically
962 compiled #defines in the board file. This option is
963 experimental and only available on a few boards. The device
964 tree is available in the global data as gd->fdt_blob.
966 U-Boot needs to get its device tree from somewhere. This can
967 be done using one of the three options below:
970 If this variable is defined, U-Boot will embed a device tree
971 binary in its image. This device tree file should be in the
972 board directory and called <soc>-<board>.dts. The binary file
973 is then picked up in board_init_f() and made available through
974 the global data structure as gd->blob.
977 If this variable is defined, U-Boot will build a device tree
978 binary. It will be called u-boot.dtb. Architecture-specific
979 code will locate it at run-time. Generally this works by:
981 cat u-boot.bin u-boot.dtb >image.bin
983 and in fact, U-Boot does this for you, creating a file called
984 u-boot-dtb.bin which is useful in the common case. You can
985 still use the individual files if you need something more
989 If this variable is defined, U-Boot will use the device tree
990 provided by the board at runtime instead of embedding one with
991 the image. Only boards defining board_fdt_blob_setup() support
992 this option (see include/fdtdec.h file).
996 If this variable is defined, it enables watchdog
997 support for the SoC. There must be support in the SoC
998 specific code for a watchdog. For the 8xx and 8260
999 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1000 register. When supported for a specific SoC is
1001 available, then no further board specific code should
1002 be needed to use it.
1005 When using a watchdog circuitry external to the used
1006 SoC, then define this variable and provide board
1007 specific code for the "hw_watchdog_reset" function.
1009 CONFIG_AT91_HW_WDT_TIMEOUT
1010 specify the timeout in seconds. default 2 seconds.
1013 CONFIG_VERSION_VARIABLE
1014 If this variable is defined, an environment variable
1015 named "ver" is created by U-Boot showing the U-Boot
1016 version as printed by the "version" command.
1017 Any change to this variable will be reverted at the
1022 When CONFIG_CMD_DATE is selected, the type of the RTC
1023 has to be selected, too. Define exactly one of the
1026 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1027 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1028 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1029 CONFIG_RTC_MC146818 - use MC146818 RTC
1030 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1031 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1032 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1033 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1034 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1035 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1036 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1037 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1038 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1041 Note that if the RTC uses I2C, then the I2C interface
1042 must also be configured. See I2C Support, below.
1045 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1047 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1048 chip-ngpio pairs that tell the PCA953X driver the number of
1049 pins supported by a particular chip.
1051 Note that if the GPIO device uses I2C, then the I2C interface
1052 must also be configured. See I2C Support, below.
1055 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1056 accesses and can checksum them or write a list of them out
1057 to memory. See the 'iotrace' command for details. This is
1058 useful for testing device drivers since it can confirm that
1059 the driver behaves the same way before and after a code
1060 change. Currently this is supported on sandbox and arm. To
1061 add support for your architecture, add '#include <iotrace.h>'
1062 to the bottom of arch/<arch>/include/asm/io.h and test.
1064 Example output from the 'iotrace stats' command is below.
1065 Note that if the trace buffer is exhausted, the checksum will
1066 still continue to operate.
1069 Start: 10000000 (buffer start address)
1070 Size: 00010000 (buffer size)
1071 Offset: 00000120 (current buffer offset)
1072 Output: 10000120 (start + offset)
1073 Count: 00000018 (number of trace records)
1074 CRC32: 9526fb66 (CRC32 of all trace records)
1076 - Timestamp Support:
1078 When CONFIG_TIMESTAMP is selected, the timestamp
1079 (date and time) of an image is printed by image
1080 commands like bootm or iminfo. This option is
1081 automatically enabled when you select CONFIG_CMD_DATE .
1083 - Partition Labels (disklabels) Supported:
1084 Zero or more of the following:
1085 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1086 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1087 Intel architecture, USB sticks, etc.
1088 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1089 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1090 bootloader. Note 2TB partition limit; see
1092 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1094 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1095 CONFIG_SCSI) you must configure support for at
1096 least one non-MTD partition type as well.
1099 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1100 board configurations files but used nowhere!
1102 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1103 be performed by calling the function
1104 ide_set_reset(int reset)
1105 which has to be defined in a board specific file
1110 Set this to enable ATAPI support.
1115 Set this to enable support for disks larger than 137GB
1116 Also look at CONFIG_SYS_64BIT_LBA.
1117 Whithout these , LBA48 support uses 32bit variables and will 'only'
1118 support disks up to 2.1TB.
1120 CONFIG_SYS_64BIT_LBA:
1121 When enabled, makes the IDE subsystem use 64bit sector addresses.
1125 At the moment only there is only support for the
1126 SYM53C8XX SCSI controller; define
1127 CONFIG_SCSI_SYM53C8XX to enable it.
1129 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1130 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1131 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1132 maximum numbers of LUNs, SCSI ID's and target
1134 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1136 The environment variable 'scsidevs' is set to the number of
1137 SCSI devices found during the last scan.
1139 - NETWORK Support (PCI):
1141 Support for Intel 8254x/8257x gigabit chips.
1144 Utility code for direct access to the SPI bus on Intel 8257x.
1145 This does not do anything useful unless you set at least one
1146 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1148 CONFIG_E1000_SPI_GENERIC
1149 Allow generic access to the SPI bus on the Intel 8257x, for
1150 example with the "sspi" command.
1153 Management command for E1000 devices. When used on devices
1154 with SPI support you can reprogram the EEPROM from U-Boot.
1157 Support for Intel 82557/82559/82559ER chips.
1158 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1159 write routine for first time initialisation.
1162 Support for Digital 2114x chips.
1163 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1164 modem chip initialisation (KS8761/QS6611).
1167 Support for National dp83815 chips.
1170 Support for National dp8382[01] gigabit chips.
1172 - NETWORK Support (other):
1174 CONFIG_DRIVER_AT91EMAC
1175 Support for AT91RM9200 EMAC.
1178 Define this to use reduced MII inteface
1180 CONFIG_DRIVER_AT91EMAC_QUIET
1181 If this defined, the driver is quiet.
1182 The driver doen't show link status messages.
1184 CONFIG_CALXEDA_XGMAC
1185 Support for the Calxeda XGMAC device
1188 Support for SMSC's LAN91C96 chips.
1190 CONFIG_LAN91C96_USE_32_BIT
1191 Define this to enable 32 bit addressing
1194 Support for SMSC's LAN91C111 chip
1196 CONFIG_SMC91111_BASE
1197 Define this to hold the physical address
1198 of the device (I/O space)
1200 CONFIG_SMC_USE_32_BIT
1201 Define this if data bus is 32 bits
1203 CONFIG_SMC_USE_IOFUNCS
1204 Define this to use i/o functions instead of macros
1205 (some hardware wont work with macros)
1207 CONFIG_DRIVER_TI_EMAC
1208 Support for davinci emac
1210 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1211 Define this if you have more then 3 PHYs.
1214 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1216 CONFIG_FTGMAC100_EGIGA
1217 Define this to use GE link update with gigabit PHY.
1218 Define this if FTGMAC100 is connected to gigabit PHY.
1219 If your system has 10/100 PHY only, it might not occur
1220 wrong behavior. Because PHY usually return timeout or
1221 useless data when polling gigabit status and gigabit
1222 control registers. This behavior won't affect the
1223 correctnessof 10/100 link speed update.
1226 Support for SMSC's LAN911x and LAN921x chips
1229 Define this to hold the physical address
1230 of the device (I/O space)
1232 CONFIG_SMC911X_32_BIT
1233 Define this if data bus is 32 bits
1235 CONFIG_SMC911X_16_BIT
1236 Define this if data bus is 16 bits. If your processor
1237 automatically converts one 32 bit word to two 16 bit
1238 words you may also try CONFIG_SMC911X_32_BIT.
1241 Support for Renesas on-chip Ethernet controller
1243 CONFIG_SH_ETHER_USE_PORT
1244 Define the number of ports to be used
1246 CONFIG_SH_ETHER_PHY_ADDR
1247 Define the ETH PHY's address
1249 CONFIG_SH_ETHER_CACHE_WRITEBACK
1250 If this option is set, the driver enables cache flush.
1254 Support for PWM module on the imx6.
1258 Support TPM devices.
1260 CONFIG_TPM_TIS_INFINEON
1261 Support for Infineon i2c bus TPM devices. Only one device
1262 per system is supported at this time.
1264 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1265 Define the burst count bytes upper limit
1268 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1270 CONFIG_TPM_ST33ZP24_I2C
1271 Support for STMicroelectronics ST33ZP24 I2C devices.
1272 Requires TPM_ST33ZP24 and I2C.
1274 CONFIG_TPM_ST33ZP24_SPI
1275 Support for STMicroelectronics ST33ZP24 SPI devices.
1276 Requires TPM_ST33ZP24 and SPI.
1278 CONFIG_TPM_ATMEL_TWI
1279 Support for Atmel TWI TPM device. Requires I2C support.
1282 Support for generic parallel port TPM devices. Only one device
1283 per system is supported at this time.
1285 CONFIG_TPM_TIS_BASE_ADDRESS
1286 Base address where the generic TPM device is mapped
1287 to. Contemporary x86 systems usually map it at
1291 Add tpm monitor functions.
1292 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1293 provides monitor access to authorized functions.
1296 Define this to enable the TPM support library which provides
1297 functional interfaces to some TPM commands.
1298 Requires support for a TPM device.
1300 CONFIG_TPM_AUTH_SESSIONS
1301 Define this to enable authorized functions in the TPM library.
1302 Requires CONFIG_TPM and CONFIG_SHA1.
1305 At the moment only the UHCI host controller is
1306 supported (PIP405, MIP405, MPC5200); define
1307 CONFIG_USB_UHCI to enable it.
1308 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1309 and define CONFIG_USB_STORAGE to enable the USB
1312 Supported are USB Keyboards and USB Floppy drives
1314 MPC5200 USB requires additional defines:
1316 for 528 MHz Clock: 0x0001bbbb
1320 for differential drivers: 0x00001000
1321 for single ended drivers: 0x00005000
1322 for differential drivers on PSC3: 0x00000100
1323 for single ended drivers on PSC3: 0x00004100
1324 CONFIG_SYS_USB_EVENT_POLL
1325 May be defined to allow interrupt polling
1326 instead of using asynchronous interrupts
1328 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1329 txfilltuning field in the EHCI controller on reset.
1331 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1332 HW module registers.
1335 Define the below if you wish to use the USB console.
1336 Once firmware is rebuilt from a serial console issue the
1337 command "setenv stdin usbtty; setenv stdout usbtty" and
1338 attach your USB cable. The Unix command "dmesg" should print
1339 it has found a new device. The environment variable usbtty
1340 can be set to gserial or cdc_acm to enable your device to
1341 appear to a USB host as a Linux gserial device or a
1342 Common Device Class Abstract Control Model serial device.
1343 If you select usbtty = gserial you should be able to enumerate
1345 # modprobe usbserial vendor=0xVendorID product=0xProductID
1346 else if using cdc_acm, simply setting the environment
1347 variable usbtty to be cdc_acm should suffice. The following
1348 might be defined in YourBoardName.h
1351 Define this to build a UDC device
1354 Define this to have a tty type of device available to
1355 talk to the UDC device
1358 Define this to enable the high speed support for usb
1359 device and usbtty. If this feature is enabled, a routine
1360 int is_usbd_high_speed(void)
1361 also needs to be defined by the driver to dynamically poll
1362 whether the enumeration has succeded at high speed or full
1365 CONFIG_SYS_CONSOLE_IS_IN_ENV
1366 Define this if you want stdin, stdout &/or stderr to
1370 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1371 Derive USB clock from external clock "blah"
1372 - CONFIG_SYS_USB_EXTC_CLK 0x02
1374 If you have a USB-IF assigned VendorID then you may wish to
1375 define your own vendor specific values either in BoardName.h
1376 or directly in usbd_vendor_info.h. If you don't define
1377 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1378 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1379 should pretend to be a Linux device to it's target host.
1381 CONFIG_USBD_MANUFACTURER
1382 Define this string as the name of your company for
1383 - CONFIG_USBD_MANUFACTURER "my company"
1385 CONFIG_USBD_PRODUCT_NAME
1386 Define this string as the name of your product
1387 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1389 CONFIG_USBD_VENDORID
1390 Define this as your assigned Vendor ID from the USB
1391 Implementors Forum. This *must* be a genuine Vendor ID
1392 to avoid polluting the USB namespace.
1393 - CONFIG_USBD_VENDORID 0xFFFF
1395 CONFIG_USBD_PRODUCTID
1396 Define this as the unique Product ID
1398 - CONFIG_USBD_PRODUCTID 0xFFFF
1400 - ULPI Layer Support:
1401 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1402 the generic ULPI layer. The generic layer accesses the ULPI PHY
1403 via the platform viewport, so you need both the genric layer and
1404 the viewport enabled. Currently only Chipidea/ARC based
1405 viewport is supported.
1406 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1407 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1408 If your ULPI phy needs a different reference clock than the
1409 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1410 the appropriate value in Hz.
1413 The MMC controller on the Intel PXA is supported. To
1414 enable this define CONFIG_MMC. The MMC can be
1415 accessed from the boot prompt by mapping the device
1416 to physical memory similar to flash. Command line is
1417 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1418 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1421 Support for Renesas on-chip MMCIF controller
1423 CONFIG_SH_MMCIF_ADDR
1424 Define the base address of MMCIF registers
1427 Define the clock frequency for MMCIF
1429 CONFIG_SUPPORT_EMMC_BOOT
1430 Enable some additional features of the eMMC boot partitions.
1432 CONFIG_SUPPORT_EMMC_RPMB
1433 Enable the commands for reading, writing and programming the
1434 key for the Replay Protection Memory Block partition in eMMC.
1436 - USB Device Firmware Update (DFU) class support:
1437 CONFIG_USB_FUNCTION_DFU
1438 This enables the USB portion of the DFU USB class
1441 This enables the command "dfu" which is used to have
1442 U-Boot create a DFU class device via USB. This command
1443 requires that the "dfu_alt_info" environment variable be
1444 set and define the alt settings to expose to the host.
1447 This enables support for exposing (e)MMC devices via DFU.
1450 This enables support for exposing NAND devices via DFU.
1453 This enables support for exposing RAM via DFU.
1454 Note: DFU spec refer to non-volatile memory usage, but
1455 allow usages beyond the scope of spec - here RAM usage,
1456 one that would help mostly the developer.
1458 CONFIG_SYS_DFU_DATA_BUF_SIZE
1459 Dfu transfer uses a buffer before writing data to the
1460 raw storage device. Make the size (in bytes) of this buffer
1461 configurable. The size of this buffer is also configurable
1462 through the "dfu_bufsiz" environment variable.
1464 CONFIG_SYS_DFU_MAX_FILE_SIZE
1465 When updating files rather than the raw storage device,
1466 we use a static buffer to copy the file into and then write
1467 the buffer once we've been given the whole file. Define
1468 this to the maximum filesize (in bytes) for the buffer.
1469 Default is 4 MiB if undefined.
1471 DFU_DEFAULT_POLL_TIMEOUT
1472 Poll timeout [ms], is the timeout a device can send to the
1473 host. The host must wait for this timeout before sending
1474 a subsequent DFU_GET_STATUS request to the device.
1476 DFU_MANIFEST_POLL_TIMEOUT
1477 Poll timeout [ms], which the device sends to the host when
1478 entering dfuMANIFEST state. Host waits this timeout, before
1479 sending again an USB request to the device.
1481 - USB Device Android Fastboot support:
1482 CONFIG_USB_FUNCTION_FASTBOOT
1483 This enables the USB part of the fastboot gadget
1486 This enables the command "fastboot" which enables the Android
1487 fastboot mode for the platform's USB device. Fastboot is a USB
1488 protocol for downloading images, flashing and device control
1489 used on Android devices.
1490 See doc/README.android-fastboot for more information.
1492 CONFIG_ANDROID_BOOT_IMAGE
1493 This enables support for booting images which use the Android
1494 image format header.
1496 CONFIG_FASTBOOT_BUF_ADDR
1497 The fastboot protocol requires a large memory buffer for
1498 downloads. Define this to the starting RAM address to use for
1501 CONFIG_FASTBOOT_BUF_SIZE
1502 The fastboot protocol requires a large memory buffer for
1503 downloads. This buffer should be as large as possible for a
1504 platform. Define this to the size available RAM for fastboot.
1506 CONFIG_FASTBOOT_FLASH
1507 The fastboot protocol includes a "flash" command for writing
1508 the downloaded image to a non-volatile storage device. Define
1509 this to enable the "fastboot flash" command.
1511 CONFIG_FASTBOOT_FLASH_MMC_DEV
1512 The fastboot "flash" command requires additional information
1513 regarding the non-volatile storage device. Define this to
1514 the eMMC device that fastboot should use to store the image.
1516 CONFIG_FASTBOOT_GPT_NAME
1517 The fastboot "flash" command supports writing the downloaded
1518 image to the Protective MBR and the Primary GUID Partition
1519 Table. (Additionally, this downloaded image is post-processed
1520 to generate and write the Backup GUID Partition Table.)
1521 This occurs when the specified "partition name" on the
1522 "fastboot flash" command line matches this value.
1523 The default is "gpt" if undefined.
1525 CONFIG_FASTBOOT_MBR_NAME
1526 The fastboot "flash" command supports writing the downloaded
1528 This occurs when the "partition name" specified on the
1529 "fastboot flash" command line matches this value.
1530 If not defined the default value "mbr" is used.
1532 - Journaling Flash filesystem support:
1534 Define these for a default partition on a NAND device
1536 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1537 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1538 Define these for a default partition on a NOR device
1540 - FAT(File Allocation Table) filesystem write function support:
1543 Define this to enable support for saving memory data as a
1544 file in FAT formatted partition.
1546 This will also enable the command "fatwrite" enabling the
1547 user to write files to FAT.
1549 - FAT(File Allocation Table) filesystem cluster size:
1550 CONFIG_FS_FAT_MAX_CLUSTSIZE
1552 Define the max cluster size for fat operations else
1553 a default value of 65536 will be defined.
1556 See Kconfig help for available keyboard drivers.
1560 Define this to enable a custom keyboard support.
1561 This simply calls drv_keyboard_init() which must be
1562 defined in your board-specific files. This option is deprecated
1563 and is only used by novena. For new boards, use driver model
1568 Enable the Freescale DIU video driver. Reference boards for
1569 SOCs that have a DIU should define this macro to enable DIU
1570 support, and should also define these other macros:
1575 CONFIG_VIDEO_SW_CURSOR
1576 CONFIG_VGA_AS_SINGLE_DEVICE
1578 CONFIG_VIDEO_BMP_LOGO
1580 The DIU driver will look for the 'video-mode' environment
1581 variable, and if defined, enable the DIU as a console during
1582 boot. See the documentation file doc/README.video for a
1583 description of this variable.
1585 - LCD Support: CONFIG_LCD
1587 Define this to enable LCD support (for output to LCD
1588 display); also select one of the supported displays
1589 by defining one of these:
1593 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1595 CONFIG_NEC_NL6448AC33:
1597 NEC NL6448AC33-18. Active, color, single scan.
1599 CONFIG_NEC_NL6448BC20
1601 NEC NL6448BC20-08. 6.5", 640x480.
1602 Active, color, single scan.
1604 CONFIG_NEC_NL6448BC33_54
1606 NEC NL6448BC33-54. 10.4", 640x480.
1607 Active, color, single scan.
1611 Sharp 320x240. Active, color, single scan.
1612 It isn't 16x9, and I am not sure what it is.
1614 CONFIG_SHARP_LQ64D341
1616 Sharp LQ64D341 display, 640x480.
1617 Active, color, single scan.
1621 HLD1045 display, 640x480.
1622 Active, color, single scan.
1626 Optrex CBL50840-2 NF-FW 99 22 M5
1628 Hitachi LMG6912RPFC-00T
1632 320x240. Black & white.
1634 CONFIG_LCD_ALIGNMENT
1636 Normally the LCD is page-aligned (typically 4KB). If this is
1637 defined then the LCD will be aligned to this value instead.
1638 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1639 here, since it is cheaper to change data cache settings on
1640 a per-section basis.
1645 Sometimes, for example if the display is mounted in portrait
1646 mode or even if it's mounted landscape but rotated by 180degree,
1647 we need to rotate our content of the display relative to the
1648 framebuffer, so that user can read the messages which are
1650 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1651 initialized with a given rotation from "vl_rot" out of
1652 "vidinfo_t" which is provided by the board specific code.
1653 The value for vl_rot is coded as following (matching to
1654 fbcon=rotate:<n> linux-kernel commandline):
1655 0 = no rotation respectively 0 degree
1656 1 = 90 degree rotation
1657 2 = 180 degree rotation
1658 3 = 270 degree rotation
1660 If CONFIG_LCD_ROTATION is not defined, the console will be
1661 initialized with 0degree rotation.
1665 Support drawing of RLE8-compressed bitmaps on the LCD.
1669 Enables an 'i2c edid' command which can read EDID
1670 information over I2C from an attached LCD display.
1672 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1674 If this option is set, the environment is checked for
1675 a variable "splashimage". If found, the usual display
1676 of logo, copyright and system information on the LCD
1677 is suppressed and the BMP image at the address
1678 specified in "splashimage" is loaded instead. The
1679 console is redirected to the "nulldev", too. This
1680 allows for a "silent" boot where a splash screen is
1681 loaded very quickly after power-on.
1683 CONFIG_SPLASHIMAGE_GUARD
1685 If this option is set, then U-Boot will prevent the environment
1686 variable "splashimage" from being set to a problematic address
1687 (see doc/README.displaying-bmps).
1688 This option is useful for targets where, due to alignment
1689 restrictions, an improperly aligned BMP image will cause a data
1690 abort. If you think you will not have problems with unaligned
1691 accesses (for example because your toolchain prevents them)
1692 there is no need to set this option.
1694 CONFIG_SPLASH_SCREEN_ALIGN
1696 If this option is set the splash image can be freely positioned
1697 on the screen. Environment variable "splashpos" specifies the
1698 position as "x,y". If a positive number is given it is used as
1699 number of pixel from left/top. If a negative number is given it
1700 is used as number of pixel from right/bottom. You can also
1701 specify 'm' for centering the image.
1704 setenv splashpos m,m
1705 => image at center of screen
1707 setenv splashpos 30,20
1708 => image at x = 30 and y = 20
1710 setenv splashpos -10,m
1711 => vertically centered image
1712 at x = dspWidth - bmpWidth - 9
1714 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1716 If this option is set, additionally to standard BMP
1717 images, gzipped BMP images can be displayed via the
1718 splashscreen support or the bmp command.
1720 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1722 If this option is set, 8-bit RLE compressed BMP images
1723 can be displayed via the splashscreen support or the
1726 - Compression support:
1729 Enabled by default to support gzip compressed images.
1733 If this option is set, support for bzip2 compressed
1734 images is included. If not, only uncompressed and gzip
1735 compressed images are supported.
1737 NOTE: the bzip2 algorithm requires a lot of RAM, so
1738 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1743 If this option is set, support for lzma compressed
1746 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1747 requires an amount of dynamic memory that is given by the
1750 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1752 Where lc and lp stand for, respectively, Literal context bits
1753 and Literal pos bits.
1755 This value is upper-bounded by 14MB in the worst case. Anyway,
1756 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1757 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1758 a very small buffer.
1760 Use the lzmainfo tool to determinate the lc and lp values and
1761 then calculate the amount of needed dynamic memory (ensuring
1762 the appropriate CONFIG_SYS_MALLOC_LEN value).
1766 If this option is set, support for LZO compressed images
1772 The address of PHY on MII bus.
1774 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1776 The clock frequency of the MII bus
1780 If this option is set, support for speed/duplex
1781 detection of gigabit PHY is included.
1783 CONFIG_PHY_RESET_DELAY
1785 Some PHY like Intel LXT971A need extra delay after
1786 reset before any MII register access is possible.
1787 For such PHY, set this option to the usec delay
1788 required. (minimum 300usec for LXT971A)
1790 CONFIG_PHY_CMD_DELAY (ppc4xx)
1792 Some PHY like Intel LXT971A need extra delay after
1793 command issued before MII status register can be read
1798 Define a default value for the IP address to use for
1799 the default Ethernet interface, in case this is not
1800 determined through e.g. bootp.
1801 (Environment variable "ipaddr")
1803 - Server IP address:
1806 Defines a default value for the IP address of a TFTP
1807 server to contact when using the "tftboot" command.
1808 (Environment variable "serverip")
1810 CONFIG_KEEP_SERVERADDR
1812 Keeps the server's MAC address, in the env 'serveraddr'
1813 for passing to bootargs (like Linux's netconsole option)
1815 - Gateway IP address:
1818 Defines a default value for the IP address of the
1819 default router where packets to other networks are
1821 (Environment variable "gatewayip")
1826 Defines a default value for the subnet mask (or
1827 routing prefix) which is used to determine if an IP
1828 address belongs to the local subnet or needs to be
1829 forwarded through a router.
1830 (Environment variable "netmask")
1832 - Multicast TFTP Mode:
1835 Defines whether you want to support multicast TFTP as per
1836 rfc-2090; for example to work with atftp. Lets lots of targets
1837 tftp down the same boot image concurrently. Note: the Ethernet
1838 driver in use must provide a function: mcast() to join/leave a
1841 - BOOTP Recovery Mode:
1842 CONFIG_BOOTP_RANDOM_DELAY
1844 If you have many targets in a network that try to
1845 boot using BOOTP, you may want to avoid that all
1846 systems send out BOOTP requests at precisely the same
1847 moment (which would happen for instance at recovery
1848 from a power failure, when all systems will try to
1849 boot, thus flooding the BOOTP server. Defining
1850 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1851 inserted before sending out BOOTP requests. The
1852 following delays are inserted then:
1854 1st BOOTP request: delay 0 ... 1 sec
1855 2nd BOOTP request: delay 0 ... 2 sec
1856 3rd BOOTP request: delay 0 ... 4 sec
1858 BOOTP requests: delay 0 ... 8 sec
1860 CONFIG_BOOTP_ID_CACHE_SIZE
1862 BOOTP packets are uniquely identified using a 32-bit ID. The
1863 server will copy the ID from client requests to responses and
1864 U-Boot will use this to determine if it is the destination of
1865 an incoming response. Some servers will check that addresses
1866 aren't in use before handing them out (usually using an ARP
1867 ping) and therefore take up to a few hundred milliseconds to
1868 respond. Network congestion may also influence the time it
1869 takes for a response to make it back to the client. If that
1870 time is too long, U-Boot will retransmit requests. In order
1871 to allow earlier responses to still be accepted after these
1872 retransmissions, U-Boot's BOOTP client keeps a small cache of
1873 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1874 cache. The default is to keep IDs for up to four outstanding
1875 requests. Increasing this will allow U-Boot to accept offers
1876 from a BOOTP client in networks with unusually high latency.
1878 - DHCP Advanced Options:
1879 You can fine tune the DHCP functionality by defining
1880 CONFIG_BOOTP_* symbols:
1882 CONFIG_BOOTP_SUBNETMASK
1883 CONFIG_BOOTP_GATEWAY
1884 CONFIG_BOOTP_HOSTNAME
1885 CONFIG_BOOTP_NISDOMAIN
1886 CONFIG_BOOTP_BOOTPATH
1887 CONFIG_BOOTP_BOOTFILESIZE
1890 CONFIG_BOOTP_SEND_HOSTNAME
1891 CONFIG_BOOTP_NTPSERVER
1892 CONFIG_BOOTP_TIMEOFFSET
1893 CONFIG_BOOTP_VENDOREX
1894 CONFIG_BOOTP_MAY_FAIL
1896 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1897 environment variable, not the BOOTP server.
1899 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1900 after the configured retry count, the call will fail
1901 instead of starting over. This can be used to fail over
1902 to Link-local IP address configuration if the DHCP server
1905 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1906 serverip from a DHCP server, it is possible that more
1907 than one DNS serverip is offered to the client.
1908 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1909 serverip will be stored in the additional environment
1910 variable "dnsip2". The first DNS serverip is always
1911 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1914 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1915 to do a dynamic update of a DNS server. To do this, they
1916 need the hostname of the DHCP requester.
1917 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1918 of the "hostname" environment variable is passed as
1919 option 12 to the DHCP server.
1921 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1923 A 32bit value in microseconds for a delay between
1924 receiving a "DHCP Offer" and sending the "DHCP Request".
1925 This fixes a problem with certain DHCP servers that don't
1926 respond 100% of the time to a "DHCP request". E.g. On an
1927 AT91RM9200 processor running at 180MHz, this delay needed
1928 to be *at least* 15,000 usec before a Windows Server 2003
1929 DHCP server would reply 100% of the time. I recommend at
1930 least 50,000 usec to be safe. The alternative is to hope
1931 that one of the retries will be successful but note that
1932 the DHCP timeout and retry process takes a longer than
1935 - Link-local IP address negotiation:
1936 Negotiate with other link-local clients on the local network
1937 for an address that doesn't require explicit configuration.
1938 This is especially useful if a DHCP server cannot be guaranteed
1939 to exist in all environments that the device must operate.
1941 See doc/README.link-local for more information.
1944 CONFIG_CDP_DEVICE_ID
1946 The device id used in CDP trigger frames.
1948 CONFIG_CDP_DEVICE_ID_PREFIX
1950 A two character string which is prefixed to the MAC address
1955 A printf format string which contains the ascii name of
1956 the port. Normally is set to "eth%d" which sets
1957 eth0 for the first Ethernet, eth1 for the second etc.
1959 CONFIG_CDP_CAPABILITIES
1961 A 32bit integer which indicates the device capabilities;
1962 0x00000010 for a normal host which does not forwards.
1966 An ascii string containing the version of the software.
1970 An ascii string containing the name of the platform.
1974 A 32bit integer sent on the trigger.
1976 CONFIG_CDP_POWER_CONSUMPTION
1978 A 16bit integer containing the power consumption of the
1979 device in .1 of milliwatts.
1981 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1983 A byte containing the id of the VLAN.
1985 - Status LED: CONFIG_LED_STATUS
1987 Several configurations allow to display the current
1988 status using a LED. For instance, the LED will blink
1989 fast while running U-Boot code, stop blinking as
1990 soon as a reply to a BOOTP request was received, and
1991 start blinking slow once the Linux kernel is running
1992 (supported by a status LED driver in the Linux
1993 kernel). Defining CONFIG_LED_STATUS enables this
1998 CONFIG_LED_STATUS_GPIO
1999 The status LED can be connected to a GPIO pin.
2000 In such cases, the gpio_led driver can be used as a
2001 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2002 to include the gpio_led driver in the U-Boot binary.
2004 CONFIG_GPIO_LED_INVERTED_TABLE
2005 Some GPIO connected LEDs may have inverted polarity in which
2006 case the GPIO high value corresponds to LED off state and
2007 GPIO low value corresponds to LED on state.
2008 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2009 with a list of GPIO LEDs that have inverted polarity.
2011 - CAN Support: CONFIG_CAN_DRIVER
2013 Defining CONFIG_CAN_DRIVER enables CAN driver support
2014 on those systems that support this (optional)
2015 feature, like the TQM8xxL modules.
2017 - I2C Support: CONFIG_SYS_I2C
2019 This enable the NEW i2c subsystem, and will allow you to use
2020 i2c commands at the u-boot command line (as long as you set
2021 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2022 based realtime clock chips or other i2c devices. See
2023 common/cmd_i2c.c for a description of the command line
2026 ported i2c driver to the new framework:
2027 - drivers/i2c/soft_i2c.c:
2028 - activate first bus with CONFIG_SYS_I2C_SOFT define
2029 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2030 for defining speed and slave address
2031 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2032 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2033 for defining speed and slave address
2034 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2035 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2036 for defining speed and slave address
2037 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2038 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2039 for defining speed and slave address
2041 - drivers/i2c/fsl_i2c.c:
2042 - activate i2c driver with CONFIG_SYS_I2C_FSL
2043 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2044 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2045 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2047 - If your board supports a second fsl i2c bus, define
2048 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2049 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2050 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2053 - drivers/i2c/tegra_i2c.c:
2054 - activate this driver with CONFIG_SYS_I2C_TEGRA
2055 - This driver adds 4 i2c buses with a fix speed from
2056 100000 and the slave addr 0!
2058 - drivers/i2c/ppc4xx_i2c.c
2059 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2060 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2061 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2063 - drivers/i2c/i2c_mxc.c
2064 - activate this driver with CONFIG_SYS_I2C_MXC
2065 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2066 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2067 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2068 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2069 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2070 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2071 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2072 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2073 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2074 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2075 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2076 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2077 If those defines are not set, default value is 100000
2078 for speed, and 0 for slave.
2080 - drivers/i2c/rcar_i2c.c:
2081 - activate this driver with CONFIG_SYS_I2C_RCAR
2082 - This driver adds 4 i2c buses
2084 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2085 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2086 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2087 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2088 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2089 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2090 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2091 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2092 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2094 - drivers/i2c/sh_i2c.c:
2095 - activate this driver with CONFIG_SYS_I2C_SH
2096 - This driver adds from 2 to 5 i2c buses
2098 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2099 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2100 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2101 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2102 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2103 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2104 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2105 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2106 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2107 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2108 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2110 - drivers/i2c/omap24xx_i2c.c
2111 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2112 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2113 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2114 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2115 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2116 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2117 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2118 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2119 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2120 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2121 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2123 - drivers/i2c/zynq_i2c.c
2124 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2125 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2126 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2128 - drivers/i2c/s3c24x0_i2c.c:
2129 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2130 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2131 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2132 with a fix speed from 100000 and the slave addr 0!
2134 - drivers/i2c/ihs_i2c.c
2135 - activate this driver with CONFIG_SYS_I2C_IHS
2136 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2137 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2138 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2139 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2140 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2141 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2142 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2143 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2144 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2145 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2146 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2147 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2148 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2149 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2150 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2151 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2152 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2153 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2154 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2155 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2156 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2160 CONFIG_SYS_NUM_I2C_BUSES
2161 Hold the number of i2c buses you want to use.
2163 CONFIG_SYS_I2C_DIRECT_BUS
2164 define this, if you don't use i2c muxes on your hardware.
2165 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2168 CONFIG_SYS_I2C_MAX_HOPS
2169 define how many muxes are maximal consecutively connected
2170 on one i2c bus. If you not use i2c muxes, omit this
2173 CONFIG_SYS_I2C_BUSES
2174 hold a list of buses you want to use, only used if
2175 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2176 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2177 CONFIG_SYS_NUM_I2C_BUSES = 9:
2179 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2180 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2181 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2182 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2183 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2184 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2185 {1, {I2C_NULL_HOP}}, \
2186 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2187 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2191 bus 0 on adapter 0 without a mux
2192 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2193 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2194 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2195 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2196 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2197 bus 6 on adapter 1 without a mux
2198 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2199 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2201 If you do not have i2c muxes on your board, omit this define.
2203 - Legacy I2C Support:
2204 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2205 then the following macros need to be defined (examples are
2206 from include/configs/lwmon.h):
2210 (Optional). Any commands necessary to enable the I2C
2211 controller or configure ports.
2213 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2217 (Only for MPC8260 CPU). The I/O port to use (the code
2218 assumes both bits are on the same port). Valid values
2219 are 0..3 for ports A..D.
2223 The code necessary to make the I2C data line active
2224 (driven). If the data line is open collector, this
2227 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2231 The code necessary to make the I2C data line tri-stated
2232 (inactive). If the data line is open collector, this
2235 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2239 Code that returns true if the I2C data line is high,
2242 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2246 If <bit> is true, sets the I2C data line high. If it
2247 is false, it clears it (low).
2249 eg: #define I2C_SDA(bit) \
2250 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2251 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2255 If <bit> is true, sets the I2C clock line high. If it
2256 is false, it clears it (low).
2258 eg: #define I2C_SCL(bit) \
2259 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2260 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2264 This delay is invoked four times per clock cycle so this
2265 controls the rate of data transfer. The data rate thus
2266 is 1 / (I2C_DELAY * 4). Often defined to be something
2269 #define I2C_DELAY udelay(2)
2271 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2273 If your arch supports the generic GPIO framework (asm/gpio.h),
2274 then you may alternatively define the two GPIOs that are to be
2275 used as SCL / SDA. Any of the previous I2C_xxx macros will
2276 have GPIO-based defaults assigned to them as appropriate.
2278 You should define these to the GPIO value as given directly to
2279 the generic GPIO functions.
2281 CONFIG_SYS_I2C_INIT_BOARD
2283 When a board is reset during an i2c bus transfer
2284 chips might think that the current transfer is still
2285 in progress. On some boards it is possible to access
2286 the i2c SCLK line directly, either by using the
2287 processor pin as a GPIO or by having a second pin
2288 connected to the bus. If this option is defined a
2289 custom i2c_init_board() routine in boards/xxx/board.c
2290 is run early in the boot sequence.
2292 CONFIG_I2C_MULTI_BUS
2294 This option allows the use of multiple I2C buses, each of which
2295 must have a controller. At any point in time, only one bus is
2296 active. To switch to a different bus, use the 'i2c dev' command.
2297 Note that bus numbering is zero-based.
2299 CONFIG_SYS_I2C_NOPROBES
2301 This option specifies a list of I2C devices that will be skipped
2302 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2303 is set, specify a list of bus-device pairs. Otherwise, specify
2304 a 1D array of device addresses
2307 #undef CONFIG_I2C_MULTI_BUS
2308 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2310 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2312 #define CONFIG_I2C_MULTI_BUS
2313 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2315 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2317 CONFIG_SYS_SPD_BUS_NUM
2319 If defined, then this indicates the I2C bus number for DDR SPD.
2320 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2322 CONFIG_SYS_RTC_BUS_NUM
2324 If defined, then this indicates the I2C bus number for the RTC.
2325 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2327 CONFIG_SYS_DTT_BUS_NUM
2329 If defined, then this indicates the I2C bus number for the DTT.
2330 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2332 CONFIG_SOFT_I2C_READ_REPEATED_START
2334 defining this will force the i2c_read() function in
2335 the soft_i2c driver to perform an I2C repeated start
2336 between writing the address pointer and reading the
2337 data. If this define is omitted the default behaviour
2338 of doing a stop-start sequence will be used. Most I2C
2339 devices can use either method, but some require one or
2342 - SPI Support: CONFIG_SPI
2344 Enables SPI driver (so far only tested with
2345 SPI EEPROM, also an instance works with Crystal A/D and
2346 D/As on the SACSng board)
2350 Enables the driver for SPI controller on SuperH. Currently
2351 only SH7757 is supported.
2355 Enables a software (bit-bang) SPI driver rather than
2356 using hardware support. This is a general purpose
2357 driver that only requires three general I/O port pins
2358 (two outputs, one input) to function. If this is
2359 defined, the board configuration must define several
2360 SPI configuration items (port pins to use, etc). For
2361 an example, see include/configs/sacsng.h.
2365 Enables a hardware SPI driver for general-purpose reads
2366 and writes. As with CONFIG_SOFT_SPI, the board configuration
2367 must define a list of chip-select function pointers.
2368 Currently supported on some MPC8xxx processors. For an
2369 example, see include/configs/mpc8349emds.h.
2373 Enables the driver for the SPI controllers on i.MX and MXC
2374 SoCs. Currently i.MX31/35/51 are supported.
2376 CONFIG_SYS_SPI_MXC_WAIT
2377 Timeout for waiting until spi transfer completed.
2378 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2380 - FPGA Support: CONFIG_FPGA
2382 Enables FPGA subsystem.
2384 CONFIG_FPGA_<vendor>
2386 Enables support for specific chip vendors.
2389 CONFIG_FPGA_<family>
2391 Enables support for FPGA family.
2392 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2396 Specify the number of FPGA devices to support.
2398 CONFIG_CMD_FPGA_LOADMK
2400 Enable support for fpga loadmk command
2402 CONFIG_CMD_FPGA_LOADP
2404 Enable support for fpga loadp command - load partial bitstream
2406 CONFIG_CMD_FPGA_LOADBP
2408 Enable support for fpga loadbp command - load partial bitstream
2411 CONFIG_SYS_FPGA_PROG_FEEDBACK
2413 Enable printing of hash marks during FPGA configuration.
2415 CONFIG_SYS_FPGA_CHECK_BUSY
2417 Enable checks on FPGA configuration interface busy
2418 status by the configuration function. This option
2419 will require a board or device specific function to
2424 If defined, a function that provides delays in the FPGA
2425 configuration driver.
2427 CONFIG_SYS_FPGA_CHECK_CTRLC
2428 Allow Control-C to interrupt FPGA configuration
2430 CONFIG_SYS_FPGA_CHECK_ERROR
2432 Check for configuration errors during FPGA bitfile
2433 loading. For example, abort during Virtex II
2434 configuration if the INIT_B line goes low (which
2435 indicated a CRC error).
2437 CONFIG_SYS_FPGA_WAIT_INIT
2439 Maximum time to wait for the INIT_B line to de-assert
2440 after PROB_B has been de-asserted during a Virtex II
2441 FPGA configuration sequence. The default time is 500
2444 CONFIG_SYS_FPGA_WAIT_BUSY
2446 Maximum time to wait for BUSY to de-assert during
2447 Virtex II FPGA configuration. The default is 5 ms.
2449 CONFIG_SYS_FPGA_WAIT_CONFIG
2451 Time to wait after FPGA configuration. The default is
2454 - Configuration Management:
2457 Some SoCs need special image types (e.g. U-Boot binary
2458 with a special header) as build targets. By defining
2459 CONFIG_BUILD_TARGET in the SoC / board header, this
2460 special image will be automatically built upon calling
2465 If defined, this string will be added to the U-Boot
2466 version information (U_BOOT_VERSION)
2468 - Vendor Parameter Protection:
2470 U-Boot considers the values of the environment
2471 variables "serial#" (Board Serial Number) and
2472 "ethaddr" (Ethernet Address) to be parameters that
2473 are set once by the board vendor / manufacturer, and
2474 protects these variables from casual modification by
2475 the user. Once set, these variables are read-only,
2476 and write or delete attempts are rejected. You can
2477 change this behaviour:
2479 If CONFIG_ENV_OVERWRITE is #defined in your config
2480 file, the write protection for vendor parameters is
2481 completely disabled. Anybody can change or delete
2484 Alternatively, if you define _both_ an ethaddr in the
2485 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2486 Ethernet address is installed in the environment,
2487 which can be changed exactly ONCE by the user. [The
2488 serial# is unaffected by this, i. e. it remains
2491 The same can be accomplished in a more flexible way
2492 for any variable by configuring the type of access
2493 to allow for those variables in the ".flags" variable
2494 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2499 Define this variable to enable the reservation of
2500 "protected RAM", i. e. RAM which is not overwritten
2501 by U-Boot. Define CONFIG_PRAM to hold the number of
2502 kB you want to reserve for pRAM. You can overwrite
2503 this default value by defining an environment
2504 variable "pram" to the number of kB you want to
2505 reserve. Note that the board info structure will
2506 still show the full amount of RAM. If pRAM is
2507 reserved, a new environment variable "mem" will
2508 automatically be defined to hold the amount of
2509 remaining RAM in a form that can be passed as boot
2510 argument to Linux, for instance like that:
2512 setenv bootargs ... mem=\${mem}
2515 This way you can tell Linux not to use this memory,
2516 either, which results in a memory region that will
2517 not be affected by reboots.
2519 *WARNING* If your board configuration uses automatic
2520 detection of the RAM size, you must make sure that
2521 this memory test is non-destructive. So far, the
2522 following board configurations are known to be
2525 IVMS8, IVML24, SPD8xx, TQM8xxL,
2526 HERMES, IP860, RPXlite, LWMON,
2529 - Access to physical memory region (> 4GB)
2530 Some basic support is provided for operations on memory not
2531 normally accessible to U-Boot - e.g. some architectures
2532 support access to more than 4GB of memory on 32-bit
2533 machines using physical address extension or similar.
2534 Define CONFIG_PHYSMEM to access this basic support, which
2535 currently only supports clearing the memory.
2540 Define this variable to stop the system in case of a
2541 fatal error, so that you have to reset it manually.
2542 This is probably NOT a good idea for an embedded
2543 system where you want the system to reboot
2544 automatically as fast as possible, but it may be
2545 useful during development since you can try to debug
2546 the conditions that lead to the situation.
2548 CONFIG_NET_RETRY_COUNT
2550 This variable defines the number of retries for
2551 network operations like ARP, RARP, TFTP, or BOOTP
2552 before giving up the operation. If not defined, a
2553 default value of 5 is used.
2557 Timeout waiting for an ARP reply in milliseconds.
2561 Timeout in milliseconds used in NFS protocol.
2562 If you encounter "ERROR: Cannot umount" in nfs command,
2563 try longer timeout such as
2564 #define CONFIG_NFS_TIMEOUT 10000UL
2566 - Command Interpreter:
2567 CONFIG_AUTO_COMPLETE
2569 Enable auto completion of commands using TAB.
2571 CONFIG_SYS_PROMPT_HUSH_PS2
2573 This defines the secondary prompt string, which is
2574 printed when the command interpreter needs more input
2575 to complete a command. Usually "> ".
2579 In the current implementation, the local variables
2580 space and global environment variables space are
2581 separated. Local variables are those you define by
2582 simply typing `name=value'. To access a local
2583 variable later on, you have write `$name' or
2584 `${name}'; to execute the contents of a variable
2585 directly type `$name' at the command prompt.
2587 Global environment variables are those you use
2588 setenv/printenv to work with. To run a command stored
2589 in such a variable, you need to use the run command,
2590 and you must not use the '$' sign to access them.
2592 To store commands and special characters in a
2593 variable, please use double quotation marks
2594 surrounding the whole text of the variable, instead
2595 of the backslashes before semicolons and special
2598 - Command Line Editing and History:
2599 CONFIG_CMDLINE_EDITING
2601 Enable editing and History functions for interactive
2602 command line input operations
2604 - Command Line PS1/PS2 support:
2605 CONFIG_CMDLINE_PS_SUPPORT
2607 Enable support for changing the command prompt string
2608 at run-time. Only static string is supported so far.
2609 The string is obtained from environment variables PS1
2612 - Default Environment:
2613 CONFIG_EXTRA_ENV_SETTINGS
2615 Define this to contain any number of null terminated
2616 strings (variable = value pairs) that will be part of
2617 the default environment compiled into the boot image.
2619 For example, place something like this in your
2620 board's config file:
2622 #define CONFIG_EXTRA_ENV_SETTINGS \
2626 Warning: This method is based on knowledge about the
2627 internal format how the environment is stored by the
2628 U-Boot code. This is NOT an official, exported
2629 interface! Although it is unlikely that this format
2630 will change soon, there is no guarantee either.
2631 You better know what you are doing here.
2633 Note: overly (ab)use of the default environment is
2634 discouraged. Make sure to check other ways to preset
2635 the environment like the "source" command or the
2638 CONFIG_ENV_VARS_UBOOT_CONFIG
2640 Define this in order to add variables describing the
2641 U-Boot build configuration to the default environment.
2642 These will be named arch, cpu, board, vendor, and soc.
2644 Enabling this option will cause the following to be defined:
2652 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2654 Define this in order to add variables describing certain
2655 run-time determined information about the hardware to the
2656 environment. These will be named board_name, board_rev.
2658 CONFIG_DELAY_ENVIRONMENT
2660 Normally the environment is loaded when the board is
2661 initialised so that it is available to U-Boot. This inhibits
2662 that so that the environment is not available until
2663 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2664 this is instead controlled by the value of
2665 /config/load-environment.
2667 - DataFlash Support:
2668 CONFIG_HAS_DATAFLASH
2670 Defining this option enables DataFlash features and
2671 allows to read/write in Dataflash via the standard
2674 - Serial Flash support
2677 Defining this option enables SPI flash commands
2678 'sf probe/read/write/erase/update'.
2680 Usage requires an initial 'probe' to define the serial
2681 flash parameters, followed by read/write/erase/update
2684 The following defaults may be provided by the platform
2685 to handle the common case when only a single serial
2686 flash is present on the system.
2688 CONFIG_SF_DEFAULT_BUS Bus identifier
2689 CONFIG_SF_DEFAULT_CS Chip-select
2690 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2691 CONFIG_SF_DEFAULT_SPEED in Hz
2695 Define this option to include a destructive SPI flash
2698 CONFIG_SF_DUAL_FLASH Dual flash memories
2700 Define this option to use dual flash support where two flash
2701 memories can be connected with a given cs line.
2702 Currently Xilinx Zynq qspi supports these type of connections.
2704 - SystemACE Support:
2707 Adding this option adds support for Xilinx SystemACE
2708 chips attached via some sort of local bus. The address
2709 of the chip must also be defined in the
2710 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2712 #define CONFIG_SYSTEMACE
2713 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2715 When SystemACE support is added, the "ace" device type
2716 becomes available to the fat commands, i.e. fatls.
2718 - TFTP Fixed UDP Port:
2721 If this is defined, the environment variable tftpsrcp
2722 is used to supply the TFTP UDP source port value.
2723 If tftpsrcp isn't defined, the normal pseudo-random port
2724 number generator is used.
2726 Also, the environment variable tftpdstp is used to supply
2727 the TFTP UDP destination port value. If tftpdstp isn't
2728 defined, the normal port 69 is used.
2730 The purpose for tftpsrcp is to allow a TFTP server to
2731 blindly start the TFTP transfer using the pre-configured
2732 target IP address and UDP port. This has the effect of
2733 "punching through" the (Windows XP) firewall, allowing
2734 the remainder of the TFTP transfer to proceed normally.
2735 A better solution is to properly configure the firewall,
2736 but sometimes that is not allowed.
2741 This enables a generic 'hash' command which can produce
2742 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2746 Enable the hash verify command (hash -v). This adds to code
2749 Note: There is also a sha1sum command, which should perhaps
2750 be deprecated in favour of 'hash sha1'.
2752 - Freescale i.MX specific commands:
2753 CONFIG_CMD_HDMIDETECT
2754 This enables 'hdmidet' command which returns true if an
2755 HDMI monitor is detected. This command is i.MX 6 specific.
2757 - bootcount support:
2758 CONFIG_BOOTCOUNT_LIMIT
2760 This enables the bootcounter support, see:
2761 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2764 enable special bootcounter support on at91sam9xe based boards.
2766 enable special bootcounter support on da850 based boards.
2767 CONFIG_BOOTCOUNT_RAM
2768 enable support for the bootcounter in RAM
2769 CONFIG_BOOTCOUNT_I2C
2770 enable support for the bootcounter on an i2c (like RTC) device.
2771 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2772 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2774 CONFIG_BOOTCOUNT_ALEN = address len
2776 - Show boot progress:
2777 CONFIG_SHOW_BOOT_PROGRESS
2779 Defining this option allows to add some board-
2780 specific code (calling a user-provided function
2781 "show_boot_progress(int)") that enables you to show
2782 the system's boot progress on some display (for
2783 example, some LED's) on your board. At the moment,
2784 the following checkpoints are implemented:
2787 Legacy uImage format:
2790 1 common/cmd_bootm.c before attempting to boot an image
2791 -1 common/cmd_bootm.c Image header has bad magic number
2792 2 common/cmd_bootm.c Image header has correct magic number
2793 -2 common/cmd_bootm.c Image header has bad checksum
2794 3 common/cmd_bootm.c Image header has correct checksum
2795 -3 common/cmd_bootm.c Image data has bad checksum
2796 4 common/cmd_bootm.c Image data has correct checksum
2797 -4 common/cmd_bootm.c Image is for unsupported architecture
2798 5 common/cmd_bootm.c Architecture check OK
2799 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2800 6 common/cmd_bootm.c Image Type check OK
2801 -6 common/cmd_bootm.c gunzip uncompression error
2802 -7 common/cmd_bootm.c Unimplemented compression type
2803 7 common/cmd_bootm.c Uncompression OK
2804 8 common/cmd_bootm.c No uncompress/copy overwrite error
2805 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2807 9 common/image.c Start initial ramdisk verification
2808 -10 common/image.c Ramdisk header has bad magic number
2809 -11 common/image.c Ramdisk header has bad checksum
2810 10 common/image.c Ramdisk header is OK
2811 -12 common/image.c Ramdisk data has bad checksum
2812 11 common/image.c Ramdisk data has correct checksum
2813 12 common/image.c Ramdisk verification complete, start loading
2814 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2815 13 common/image.c Start multifile image verification
2816 14 common/image.c No initial ramdisk, no multifile, continue.
2818 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2820 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2821 -31 post/post.c POST test failed, detected by post_output_backlog()
2822 -32 post/post.c POST test failed, detected by post_run_single()
2824 34 common/cmd_doc.c before loading a Image from a DOC device
2825 -35 common/cmd_doc.c Bad usage of "doc" command
2826 35 common/cmd_doc.c correct usage of "doc" command
2827 -36 common/cmd_doc.c No boot device
2828 36 common/cmd_doc.c correct boot device
2829 -37 common/cmd_doc.c Unknown Chip ID on boot device
2830 37 common/cmd_doc.c correct chip ID found, device available
2831 -38 common/cmd_doc.c Read Error on boot device
2832 38 common/cmd_doc.c reading Image header from DOC device OK
2833 -39 common/cmd_doc.c Image header has bad magic number
2834 39 common/cmd_doc.c Image header has correct magic number
2835 -40 common/cmd_doc.c Error reading Image from DOC device
2836 40 common/cmd_doc.c Image header has correct magic number
2837 41 common/cmd_ide.c before loading a Image from a IDE device
2838 -42 common/cmd_ide.c Bad usage of "ide" command
2839 42 common/cmd_ide.c correct usage of "ide" command
2840 -43 common/cmd_ide.c No boot device
2841 43 common/cmd_ide.c boot device found
2842 -44 common/cmd_ide.c Device not available
2843 44 common/cmd_ide.c Device available
2844 -45 common/cmd_ide.c wrong partition selected
2845 45 common/cmd_ide.c partition selected
2846 -46 common/cmd_ide.c Unknown partition table
2847 46 common/cmd_ide.c valid partition table found
2848 -47 common/cmd_ide.c Invalid partition type
2849 47 common/cmd_ide.c correct partition type
2850 -48 common/cmd_ide.c Error reading Image Header on boot device
2851 48 common/cmd_ide.c reading Image Header from IDE device OK
2852 -49 common/cmd_ide.c Image header has bad magic number
2853 49 common/cmd_ide.c Image header has correct magic number
2854 -50 common/cmd_ide.c Image header has bad checksum
2855 50 common/cmd_ide.c Image header has correct checksum
2856 -51 common/cmd_ide.c Error reading Image from IDE device
2857 51 common/cmd_ide.c reading Image from IDE device OK
2858 52 common/cmd_nand.c before loading a Image from a NAND device
2859 -53 common/cmd_nand.c Bad usage of "nand" command
2860 53 common/cmd_nand.c correct usage of "nand" command
2861 -54 common/cmd_nand.c No boot device
2862 54 common/cmd_nand.c boot device found
2863 -55 common/cmd_nand.c Unknown Chip ID on boot device
2864 55 common/cmd_nand.c correct chip ID found, device available
2865 -56 common/cmd_nand.c Error reading Image Header on boot device
2866 56 common/cmd_nand.c reading Image Header from NAND device OK
2867 -57 common/cmd_nand.c Image header has bad magic number
2868 57 common/cmd_nand.c Image header has correct magic number
2869 -58 common/cmd_nand.c Error reading Image from NAND device
2870 58 common/cmd_nand.c reading Image from NAND device OK
2872 -60 common/env_common.c Environment has a bad CRC, using default
2874 64 net/eth.c starting with Ethernet configuration.
2875 -64 net/eth.c no Ethernet found.
2876 65 net/eth.c Ethernet found.
2878 -80 common/cmd_net.c usage wrong
2879 80 common/cmd_net.c before calling net_loop()
2880 -81 common/cmd_net.c some error in net_loop() occurred
2881 81 common/cmd_net.c net_loop() back without error
2882 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2883 82 common/cmd_net.c trying automatic boot
2884 83 common/cmd_net.c running "source" command
2885 -83 common/cmd_net.c some error in automatic boot or "source" command
2886 84 common/cmd_net.c end without errors
2891 100 common/cmd_bootm.c Kernel FIT Image has correct format
2892 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2893 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2894 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2895 102 common/cmd_bootm.c Kernel unit name specified
2896 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2897 103 common/cmd_bootm.c Found configuration node
2898 104 common/cmd_bootm.c Got kernel subimage node offset
2899 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2900 105 common/cmd_bootm.c Kernel subimage hash verification OK
2901 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2902 106 common/cmd_bootm.c Architecture check OK
2903 -106 common/cmd_bootm.c Kernel subimage has wrong type
2904 107 common/cmd_bootm.c Kernel subimage type OK
2905 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2906 108 common/cmd_bootm.c Got kernel subimage data/size
2907 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2908 -109 common/cmd_bootm.c Can't get kernel subimage type
2909 -110 common/cmd_bootm.c Can't get kernel subimage comp
2910 -111 common/cmd_bootm.c Can't get kernel subimage os
2911 -112 common/cmd_bootm.c Can't get kernel subimage load address
2912 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2914 120 common/image.c Start initial ramdisk verification
2915 -120 common/image.c Ramdisk FIT image has incorrect format
2916 121 common/image.c Ramdisk FIT image has correct format
2917 122 common/image.c No ramdisk subimage unit name, using configuration
2918 -122 common/image.c Can't get configuration for ramdisk subimage
2919 123 common/image.c Ramdisk unit name specified
2920 -124 common/image.c Can't get ramdisk subimage node offset
2921 125 common/image.c Got ramdisk subimage node offset
2922 -125 common/image.c Ramdisk subimage hash verification failed
2923 126 common/image.c Ramdisk subimage hash verification OK
2924 -126 common/image.c Ramdisk subimage for unsupported architecture
2925 127 common/image.c Architecture check OK
2926 -127 common/image.c Can't get ramdisk subimage data/size
2927 128 common/image.c Got ramdisk subimage data/size
2928 129 common/image.c Can't get ramdisk load address
2929 -129 common/image.c Got ramdisk load address
2931 -130 common/cmd_doc.c Incorrect FIT image format
2932 131 common/cmd_doc.c FIT image format OK
2934 -140 common/cmd_ide.c Incorrect FIT image format
2935 141 common/cmd_ide.c FIT image format OK
2937 -150 common/cmd_nand.c Incorrect FIT image format
2938 151 common/cmd_nand.c FIT image format OK
2940 - legacy image format:
2941 CONFIG_IMAGE_FORMAT_LEGACY
2942 enables the legacy image format support in U-Boot.
2945 enabled if CONFIG_FIT_SIGNATURE is not defined.
2947 CONFIG_DISABLE_IMAGE_LEGACY
2948 disable the legacy image format
2950 This define is introduced, as the legacy image format is
2951 enabled per default for backward compatibility.
2953 - Standalone program support:
2954 CONFIG_STANDALONE_LOAD_ADDR
2956 This option defines a board specific value for the
2957 address where standalone program gets loaded, thus
2958 overwriting the architecture dependent default
2961 - Frame Buffer Address:
2964 Define CONFIG_FB_ADDR if you want to use specific
2965 address for frame buffer. This is typically the case
2966 when using a graphics controller has separate video
2967 memory. U-Boot will then place the frame buffer at
2968 the given address instead of dynamically reserving it
2969 in system RAM by calling lcd_setmem(), which grabs
2970 the memory for the frame buffer depending on the
2971 configured panel size.
2973 Please see board_init_f function.
2975 - Automatic software updates via TFTP server
2977 CONFIG_UPDATE_TFTP_CNT_MAX
2978 CONFIG_UPDATE_TFTP_MSEC_MAX
2980 These options enable and control the auto-update feature;
2981 for a more detailed description refer to doc/README.update.
2983 - MTD Support (mtdparts command, UBI support)
2986 Adds the MTD device infrastructure from the Linux kernel.
2987 Needed for mtdparts command support.
2989 CONFIG_MTD_PARTITIONS
2991 Adds the MTD partitioning infrastructure from the Linux
2992 kernel. Needed for UBI support.
2997 Adds commands for interacting with MTD partitions formatted
2998 with the UBI flash translation layer
3000 Requires also defining CONFIG_RBTREE
3002 CONFIG_UBI_SILENCE_MSG
3004 Make the verbose messages from UBI stop printing. This leaves
3005 warnings and errors enabled.
3008 CONFIG_MTD_UBI_WL_THRESHOLD
3009 This parameter defines the maximum difference between the highest
3010 erase counter value and the lowest erase counter value of eraseblocks
3011 of UBI devices. When this threshold is exceeded, UBI starts performing
3012 wear leveling by means of moving data from eraseblock with low erase
3013 counter to eraseblocks with high erase counter.
3015 The default value should be OK for SLC NAND flashes, NOR flashes and
3016 other flashes which have eraseblock life-cycle 100000 or more.
3017 However, in case of MLC NAND flashes which typically have eraseblock
3018 life-cycle less than 10000, the threshold should be lessened (e.g.,
3019 to 128 or 256, although it does not have to be power of 2).
3023 CONFIG_MTD_UBI_BEB_LIMIT
3024 This option specifies the maximum bad physical eraseblocks UBI
3025 expects on the MTD device (per 1024 eraseblocks). If the
3026 underlying flash does not admit of bad eraseblocks (e.g. NOR
3027 flash), this value is ignored.
3029 NAND datasheets often specify the minimum and maximum NVM
3030 (Number of Valid Blocks) for the flashes' endurance lifetime.
3031 The maximum expected bad eraseblocks per 1024 eraseblocks
3032 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3033 which gives 20 for most NANDs (MaxNVB is basically the total
3034 count of eraseblocks on the chip).
3036 To put it differently, if this value is 20, UBI will try to
3037 reserve about 1.9% of physical eraseblocks for bad blocks
3038 handling. And that will be 1.9% of eraseblocks on the entire
3039 NAND chip, not just the MTD partition UBI attaches. This means
3040 that if you have, say, a NAND flash chip admits maximum 40 bad
3041 eraseblocks, and it is split on two MTD partitions of the same
3042 size, UBI will reserve 40 eraseblocks when attaching a
3047 CONFIG_MTD_UBI_FASTMAP
3048 Fastmap is a mechanism which allows attaching an UBI device
3049 in nearly constant time. Instead of scanning the whole MTD device it
3050 only has to locate a checkpoint (called fastmap) on the device.
3051 The on-flash fastmap contains all information needed to attach
3052 the device. Using fastmap makes only sense on large devices where
3053 attaching by scanning takes long. UBI will not automatically install
3054 a fastmap on old images, but you can set the UBI parameter
3055 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3056 that fastmap-enabled images are still usable with UBI implementations
3057 without fastmap support. On typical flash devices the whole fastmap
3058 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3060 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3061 Set this parameter to enable fastmap automatically on images
3065 CONFIG_MTD_UBI_FM_DEBUG
3066 Enable UBI fastmap debug
3072 Adds commands for interacting with UBI volumes formatted as
3073 UBIFS. UBIFS is read-only in u-boot.
3075 Requires UBI support as well as CONFIG_LZO
3077 CONFIG_UBIFS_SILENCE_MSG
3079 Make the verbose messages from UBIFS stop printing. This leaves
3080 warnings and errors enabled.
3084 Enable building of SPL globally.
3087 LDSCRIPT for linking the SPL binary.
3089 CONFIG_SPL_MAX_FOOTPRINT
3090 Maximum size in memory allocated to the SPL, BSS included.
3091 When defined, the linker checks that the actual memory
3092 used by SPL from _start to __bss_end does not exceed it.
3093 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3094 must not be both defined at the same time.
3097 Maximum size of the SPL image (text, data, rodata, and
3098 linker lists sections), BSS excluded.
3099 When defined, the linker checks that the actual size does
3102 CONFIG_SPL_TEXT_BASE
3103 TEXT_BASE for linking the SPL binary.
3105 CONFIG_SPL_RELOC_TEXT_BASE
3106 Address to relocate to. If unspecified, this is equal to
3107 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3109 CONFIG_SPL_BSS_START_ADDR
3110 Link address for the BSS within the SPL binary.
3112 CONFIG_SPL_BSS_MAX_SIZE
3113 Maximum size in memory allocated to the SPL BSS.
3114 When defined, the linker checks that the actual memory used
3115 by SPL from __bss_start to __bss_end does not exceed it.
3116 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3117 must not be both defined at the same time.
3120 Adress of the start of the stack SPL will use
3122 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3123 When defined, SPL will panic() if the image it has
3124 loaded does not have a signature.
3125 Defining this is useful when code which loads images
3126 in SPL cannot guarantee that absolutely all read errors
3128 An example is the LPC32XX MLC NAND driver, which will
3129 consider that a completely unreadable NAND block is bad,
3130 and thus should be skipped silently.
3132 CONFIG_SPL_RELOC_STACK
3133 Adress of the start of the stack SPL will use after
3134 relocation. If unspecified, this is equal to
3137 CONFIG_SYS_SPL_MALLOC_START
3138 Starting address of the malloc pool used in SPL.
3139 When this option is set the full malloc is used in SPL and
3140 it is set up by spl_init() and before that, the simple malloc()
3141 can be used if CONFIG_SYS_MALLOC_F is defined.
3143 CONFIG_SYS_SPL_MALLOC_SIZE
3144 The size of the malloc pool used in SPL.
3146 CONFIG_SPL_FRAMEWORK
3147 Enable the SPL framework under common/. This framework
3148 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3149 NAND loading of the Linux Kernel.
3152 Enable booting directly to an OS from SPL.
3153 See also: doc/README.falcon
3155 CONFIG_SPL_DISPLAY_PRINT
3156 For ARM, enable an optional function to print more information
3157 about the running system.
3159 CONFIG_SPL_INIT_MINIMAL
3160 Arch init code should be built for a very small image
3162 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3163 Partition on the MMC to load U-Boot from when the MMC is being
3166 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3167 Sector to load kernel uImage from when MMC is being
3168 used in raw mode (for Falcon mode)
3170 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3171 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3172 Sector and number of sectors to load kernel argument
3173 parameters from when MMC is being used in raw mode
3176 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3177 Partition on the MMC to load U-Boot from when the MMC is being
3180 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3181 Filename to read to load U-Boot when reading from filesystem
3183 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3184 Filename to read to load kernel uImage when reading
3185 from filesystem (for Falcon mode)
3187 CONFIG_SPL_FS_LOAD_ARGS_NAME
3188 Filename to read to load kernel argument parameters
3189 when reading from filesystem (for Falcon mode)
3191 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3192 Set this for NAND SPL on PPC mpc83xx targets, so that
3193 start.S waits for the rest of the SPL to load before
3194 continuing (the hardware starts execution after just
3195 loading the first page rather than the full 4K).
3197 CONFIG_SPL_SKIP_RELOCATE
3198 Avoid SPL relocation
3200 CONFIG_SPL_NAND_BASE
3201 Include nand_base.c in the SPL. Requires
3202 CONFIG_SPL_NAND_DRIVERS.
3204 CONFIG_SPL_NAND_DRIVERS
3205 SPL uses normal NAND drivers, not minimal drivers.
3208 Include standard software ECC in the SPL
3210 CONFIG_SPL_NAND_SIMPLE
3211 Support for NAND boot using simple NAND drivers that
3212 expose the cmd_ctrl() interface.
3215 Support for a lightweight UBI (fastmap) scanner and
3218 CONFIG_SPL_NAND_RAW_ONLY
3219 Support to boot only raw u-boot.bin images. Use this only
3220 if you need to save space.
3222 CONFIG_SPL_COMMON_INIT_DDR
3223 Set for common ddr init with serial presence detect in
3226 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3227 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3228 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3229 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3230 CONFIG_SYS_NAND_ECCBYTES
3231 Defines the size and behavior of the NAND that SPL uses
3234 CONFIG_SPL_NAND_BOOT
3235 Add support NAND boot
3237 CONFIG_SYS_NAND_U_BOOT_OFFS
3238 Location in NAND to read U-Boot from
3240 CONFIG_SYS_NAND_U_BOOT_DST
3241 Location in memory to load U-Boot to
3243 CONFIG_SYS_NAND_U_BOOT_SIZE
3244 Size of image to load
3246 CONFIG_SYS_NAND_U_BOOT_START
3247 Entry point in loaded image to jump to
3249 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3250 Define this if you need to first read the OOB and then the
3251 data. This is used, for example, on davinci platforms.
3253 CONFIG_SPL_OMAP3_ID_NAND
3254 Support for an OMAP3-specific set of functions to return the
3255 ID and MFR of the first attached NAND chip, if present.
3257 CONFIG_SPL_RAM_DEVICE
3258 Support for running image already present in ram, in SPL binary
3261 Image offset to which the SPL should be padded before appending
3262 the SPL payload. By default, this is defined as
3263 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3264 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3265 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3268 Final target image containing SPL and payload. Some SPLs
3269 use an arch-specific makefile fragment instead, for
3270 example if more than one image needs to be produced.
3272 CONFIG_FIT_SPL_PRINT
3273 Printing information about a FIT image adds quite a bit of
3274 code to SPL. So this is normally disabled in SPL. Use this
3275 option to re-enable it. This will affect the output of the
3276 bootm command when booting a FIT image.
3280 Enable building of TPL globally.
3283 Image offset to which the TPL should be padded before appending
3284 the TPL payload. By default, this is defined as
3285 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3286 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3287 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3289 - Interrupt support (PPC):
3291 There are common interrupt_init() and timer_interrupt()
3292 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3293 for CPU specific initialization. interrupt_init_cpu()
3294 should set decrementer_count to appropriate value. If
3295 CPU resets decrementer automatically after interrupt
3296 (ppc4xx) it should set decrementer_count to zero.
3297 timer_interrupt() calls timer_interrupt_cpu() for CPU
3298 specific handling. If board has watchdog / status_led
3299 / other_activity_monitor it works automatically from
3300 general timer_interrupt().
3303 Board initialization settings:
3304 ------------------------------
3306 During Initialization u-boot calls a number of board specific functions
3307 to allow the preparation of board specific prerequisites, e.g. pin setup
3308 before drivers are initialized. To enable these callbacks the
3309 following configuration macros have to be defined. Currently this is
3310 architecture specific, so please check arch/your_architecture/lib/board.c
3311 typically in board_init_f() and board_init_r().
3313 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3314 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3315 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3316 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3318 Configuration Settings:
3319 -----------------------
3321 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3322 Optionally it can be defined to support 64-bit memory commands.
3324 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3325 undefine this when you're short of memory.
3327 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3328 width of the commands listed in the 'help' command output.
3330 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3331 prompt for user input.
3333 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3335 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3337 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3339 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3340 the application (usually a Linux kernel) when it is
3343 - CONFIG_SYS_BAUDRATE_TABLE:
3344 List of legal baudrate settings for this board.
3346 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3347 Begin and End addresses of the area used by the
3350 - CONFIG_SYS_ALT_MEMTEST:
3351 Enable an alternate, more extensive memory test.
3353 - CONFIG_SYS_MEMTEST_SCRATCH:
3354 Scratch address used by the alternate memory test
3355 You only need to set this if address zero isn't writeable
3357 - CONFIG_SYS_MEM_RESERVE_SECURE
3358 Only implemented for ARMv8 for now.
3359 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3360 is substracted from total RAM and won't be reported to OS.
3361 This memory can be used as secure memory. A variable
3362 gd->arch.secure_ram is used to track the location. In systems
3363 the RAM base is not zero, or RAM is divided into banks,
3364 this variable needs to be recalcuated to get the address.
3366 - CONFIG_SYS_MEM_TOP_HIDE:
3367 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3368 this specified memory area will get subtracted from the top
3369 (end) of RAM and won't get "touched" at all by U-Boot. By
3370 fixing up gd->ram_size the Linux kernel should gets passed
3371 the now "corrected" memory size and won't touch it either.
3372 This should work for arch/ppc and arch/powerpc. Only Linux
3373 board ports in arch/powerpc with bootwrapper support that
3374 recalculate the memory size from the SDRAM controller setup
3375 will have to get fixed in Linux additionally.
3377 This option can be used as a workaround for the 440EPx/GRx
3378 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3381 WARNING: Please make sure that this value is a multiple of
3382 the Linux page size (normally 4k). If this is not the case,
3383 then the end address of the Linux memory will be located at a
3384 non page size aligned address and this could cause major
3387 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3388 Enable temporary baudrate change while serial download
3390 - CONFIG_SYS_SDRAM_BASE:
3391 Physical start address of SDRAM. _Must_ be 0 here.
3393 - CONFIG_SYS_FLASH_BASE:
3394 Physical start address of Flash memory.
3396 - CONFIG_SYS_MONITOR_BASE:
3397 Physical start address of boot monitor code (set by
3398 make config files to be same as the text base address
3399 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3400 CONFIG_SYS_FLASH_BASE when booting from flash.
3402 - CONFIG_SYS_MONITOR_LEN:
3403 Size of memory reserved for monitor code, used to
3404 determine _at_compile_time_ (!) if the environment is
3405 embedded within the U-Boot image, or in a separate
3408 - CONFIG_SYS_MALLOC_LEN:
3409 Size of DRAM reserved for malloc() use.
3411 - CONFIG_SYS_MALLOC_F_LEN
3412 Size of the malloc() pool for use before relocation. If
3413 this is defined, then a very simple malloc() implementation
3414 will become available before relocation. The address is just
3415 below the global data, and the stack is moved down to make
3418 This feature allocates regions with increasing addresses
3419 within the region. calloc() is supported, but realloc()
3420 is not available. free() is supported but does nothing.
3421 The memory will be freed (or in fact just forgotten) when
3422 U-Boot relocates itself.
3424 - CONFIG_SYS_MALLOC_SIMPLE
3425 Provides a simple and small malloc() and calloc() for those
3426 boards which do not use the full malloc in SPL (which is
3427 enabled with CONFIG_SYS_SPL_MALLOC_START).
3429 - CONFIG_SYS_NONCACHED_MEMORY:
3430 Size of non-cached memory area. This area of memory will be
3431 typically located right below the malloc() area and mapped
3432 uncached in the MMU. This is useful for drivers that would
3433 otherwise require a lot of explicit cache maintenance. For
3434 some drivers it's also impossible to properly maintain the
3435 cache. For example if the regions that need to be flushed
3436 are not a multiple of the cache-line size, *and* padding
3437 cannot be allocated between the regions to align them (i.e.
3438 if the HW requires a contiguous array of regions, and the
3439 size of each region is not cache-aligned), then a flush of
3440 one region may result in overwriting data that hardware has
3441 written to another region in the same cache-line. This can
3442 happen for example in network drivers where descriptors for
3443 buffers are typically smaller than the CPU cache-line (e.g.
3444 16 bytes vs. 32 or 64 bytes).
3446 Non-cached memory is only supported on 32-bit ARM at present.
3448 - CONFIG_SYS_BOOTM_LEN:
3449 Normally compressed uImages are limited to an
3450 uncompressed size of 8 MBytes. If this is not enough,
3451 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3452 to adjust this setting to your needs.
3454 - CONFIG_SYS_BOOTMAPSZ:
3455 Maximum size of memory mapped by the startup code of
3456 the Linux kernel; all data that must be processed by
3457 the Linux kernel (bd_info, boot arguments, FDT blob if
3458 used) must be put below this limit, unless "bootm_low"
3459 environment variable is defined and non-zero. In such case
3460 all data for the Linux kernel must be between "bootm_low"
3461 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3462 variable "bootm_mapsize" will override the value of
3463 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3464 then the value in "bootm_size" will be used instead.
3466 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3467 Enable initrd_high functionality. If defined then the
3468 initrd_high feature is enabled and the bootm ramdisk subcommand
3471 - CONFIG_SYS_BOOT_GET_CMDLINE:
3472 Enables allocating and saving kernel cmdline in space between
3473 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3475 - CONFIG_SYS_BOOT_GET_KBD:
3476 Enables allocating and saving a kernel copy of the bd_info in
3477 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3479 - CONFIG_SYS_MAX_FLASH_BANKS:
3480 Max number of Flash memory banks
3482 - CONFIG_SYS_MAX_FLASH_SECT:
3483 Max number of sectors on a Flash chip
3485 - CONFIG_SYS_FLASH_ERASE_TOUT:
3486 Timeout for Flash erase operations (in ms)
3488 - CONFIG_SYS_FLASH_WRITE_TOUT:
3489 Timeout for Flash write operations (in ms)
3491 - CONFIG_SYS_FLASH_LOCK_TOUT
3492 Timeout for Flash set sector lock bit operation (in ms)
3494 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3495 Timeout for Flash clear lock bits operation (in ms)
3497 - CONFIG_SYS_FLASH_PROTECTION
3498 If defined, hardware flash sectors protection is used
3499 instead of U-Boot software protection.
3501 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3503 Enable TFTP transfers directly to flash memory;
3504 without this option such a download has to be
3505 performed in two steps: (1) download to RAM, and (2)
3506 copy from RAM to flash.
3508 The two-step approach is usually more reliable, since
3509 you can check if the download worked before you erase
3510 the flash, but in some situations (when system RAM is
3511 too limited to allow for a temporary copy of the
3512 downloaded image) this option may be very useful.
3514 - CONFIG_SYS_FLASH_CFI:
3515 Define if the flash driver uses extra elements in the
3516 common flash structure for storing flash geometry.
3518 - CONFIG_FLASH_CFI_DRIVER
3519 This option also enables the building of the cfi_flash driver
3520 in the drivers directory
3522 - CONFIG_FLASH_CFI_MTD
3523 This option enables the building of the cfi_mtd driver
3524 in the drivers directory. The driver exports CFI flash
3527 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3528 Use buffered writes to flash.
3530 - CONFIG_FLASH_SPANSION_S29WS_N
3531 s29ws-n MirrorBit flash has non-standard addresses for buffered
3534 - CONFIG_SYS_FLASH_QUIET_TEST
3535 If this option is defined, the common CFI flash doesn't
3536 print it's warning upon not recognized FLASH banks. This
3537 is useful, if some of the configured banks are only
3538 optionally available.
3540 - CONFIG_FLASH_SHOW_PROGRESS
3541 If defined (must be an integer), print out countdown
3542 digits and dots. Recommended value: 45 (9..1) for 80
3543 column displays, 15 (3..1) for 40 column displays.
3545 - CONFIG_FLASH_VERIFY
3546 If defined, the content of the flash (destination) is compared
3547 against the source after the write operation. An error message
3548 will be printed when the contents are not identical.
3549 Please note that this option is useless in nearly all cases,
3550 since such flash programming errors usually are detected earlier
3551 while unprotecting/erasing/programming. Please only enable
3552 this option if you really know what you are doing.
3554 - CONFIG_SYS_RX_ETH_BUFFER:
3555 Defines the number of Ethernet receive buffers. On some
3556 Ethernet controllers it is recommended to set this value
3557 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3558 buffers can be full shortly after enabling the interface
3559 on high Ethernet traffic.
3560 Defaults to 4 if not defined.
3562 - CONFIG_ENV_MAX_ENTRIES
3564 Maximum number of entries in the hash table that is used
3565 internally to store the environment settings. The default
3566 setting is supposed to be generous and should work in most
3567 cases. This setting can be used to tune behaviour; see
3568 lib/hashtable.c for details.
3570 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3571 - CONFIG_ENV_FLAGS_LIST_STATIC
3572 Enable validation of the values given to environment variables when
3573 calling env set. Variables can be restricted to only decimal,
3574 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3575 the variables can also be restricted to IP address or MAC address.
3577 The format of the list is:
3578 type_attribute = [s|d|x|b|i|m]
3579 access_attribute = [a|r|o|c]
3580 attributes = type_attribute[access_attribute]
3581 entry = variable_name[:attributes]
3584 The type attributes are:
3585 s - String (default)
3588 b - Boolean ([1yYtT|0nNfF])
3592 The access attributes are:
3598 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3599 Define this to a list (string) to define the ".flags"
3600 environment variable in the default or embedded environment.
3602 - CONFIG_ENV_FLAGS_LIST_STATIC
3603 Define this to a list (string) to define validation that
3604 should be done if an entry is not found in the ".flags"
3605 environment variable. To override a setting in the static
3606 list, simply add an entry for the same variable name to the
3609 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3610 regular expression. This allows multiple variables to define the same
3611 flags without explicitly listing them for each variable.
3613 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3614 If defined, don't allow the -f switch to env set override variable
3618 If stdint.h is available with your toolchain you can define this
3619 option to enable it. You can provide option 'USE_STDINT=1' when
3620 building U-Boot to enable this.
3622 The following definitions that deal with the placement and management
3623 of environment data (variable area); in general, we support the
3624 following configurations:
3626 - CONFIG_BUILD_ENVCRC:
3628 Builds up envcrc with the target environment so that external utils
3629 may easily extract it and embed it in final U-Boot images.
3631 - CONFIG_ENV_IS_IN_FLASH:
3633 Define this if the environment is in flash memory.
3635 a) The environment occupies one whole flash sector, which is
3636 "embedded" in the text segment with the U-Boot code. This
3637 happens usually with "bottom boot sector" or "top boot
3638 sector" type flash chips, which have several smaller
3639 sectors at the start or the end. For instance, such a
3640 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3641 such a case you would place the environment in one of the
3642 4 kB sectors - with U-Boot code before and after it. With
3643 "top boot sector" type flash chips, you would put the
3644 environment in one of the last sectors, leaving a gap
3645 between U-Boot and the environment.
3647 - CONFIG_ENV_OFFSET:
3649 Offset of environment data (variable area) to the
3650 beginning of flash memory; for instance, with bottom boot
3651 type flash chips the second sector can be used: the offset
3652 for this sector is given here.
3654 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3658 This is just another way to specify the start address of
3659 the flash sector containing the environment (instead of
3662 - CONFIG_ENV_SECT_SIZE:
3664 Size of the sector containing the environment.
3667 b) Sometimes flash chips have few, equal sized, BIG sectors.
3668 In such a case you don't want to spend a whole sector for
3673 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3674 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3675 of this flash sector for the environment. This saves
3676 memory for the RAM copy of the environment.
3678 It may also save flash memory if you decide to use this
3679 when your environment is "embedded" within U-Boot code,
3680 since then the remainder of the flash sector could be used
3681 for U-Boot code. It should be pointed out that this is
3682 STRONGLY DISCOURAGED from a robustness point of view:
3683 updating the environment in flash makes it always
3684 necessary to erase the WHOLE sector. If something goes
3685 wrong before the contents has been restored from a copy in
3686 RAM, your target system will be dead.
3688 - CONFIG_ENV_ADDR_REDUND
3689 CONFIG_ENV_SIZE_REDUND
3691 These settings describe a second storage area used to hold
3692 a redundant copy of the environment data, so that there is
3693 a valid backup copy in case there is a power failure during
3694 a "saveenv" operation.
3696 BE CAREFUL! Any changes to the flash layout, and some changes to the
3697 source code will make it necessary to adapt <board>/u-boot.lds*
3701 - CONFIG_ENV_IS_IN_NVRAM:
3703 Define this if you have some non-volatile memory device
3704 (NVRAM, battery buffered SRAM) which you want to use for the
3710 These two #defines are used to determine the memory area you
3711 want to use for environment. It is assumed that this memory
3712 can just be read and written to, without any special
3715 BE CAREFUL! The first access to the environment happens quite early
3716 in U-Boot initialization (when we try to get the setting of for the
3717 console baudrate). You *MUST* have mapped your NVRAM area then, or
3720 Please note that even with NVRAM we still use a copy of the
3721 environment in RAM: we could work on NVRAM directly, but we want to
3722 keep settings there always unmodified except somebody uses "saveenv"
3723 to save the current settings.
3726 - CONFIG_ENV_IS_IN_EEPROM:
3728 Use this if you have an EEPROM or similar serial access
3729 device and a driver for it.
3731 - CONFIG_ENV_OFFSET:
3734 These two #defines specify the offset and size of the
3735 environment area within the total memory of your EEPROM.
3737 - CONFIG_SYS_I2C_EEPROM_ADDR:
3738 If defined, specified the chip address of the EEPROM device.
3739 The default address is zero.
3741 - CONFIG_SYS_I2C_EEPROM_BUS:
3742 If defined, specified the i2c bus of the EEPROM device.
3744 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3745 If defined, the number of bits used to address bytes in a
3746 single page in the EEPROM device. A 64 byte page, for example
3747 would require six bits.
3749 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3750 If defined, the number of milliseconds to delay between
3751 page writes. The default is zero milliseconds.
3753 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3754 The length in bytes of the EEPROM memory array address. Note
3755 that this is NOT the chip address length!
3757 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3758 EEPROM chips that implement "address overflow" are ones
3759 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3760 address and the extra bits end up in the "chip address" bit
3761 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3764 Note that we consider the length of the address field to
3765 still be one byte because the extra address bits are hidden
3766 in the chip address.
3768 - CONFIG_SYS_EEPROM_SIZE:
3769 The size in bytes of the EEPROM device.
3771 - CONFIG_ENV_EEPROM_IS_ON_I2C
3772 define this, if you have I2C and SPI activated, and your
3773 EEPROM, which holds the environment, is on the I2C bus.
3775 - CONFIG_I2C_ENV_EEPROM_BUS
3776 if you have an Environment on an EEPROM reached over
3777 I2C muxes, you can define here, how to reach this
3778 EEPROM. For example:
3780 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3782 EEPROM which holds the environment, is reached over
3783 a pca9547 i2c mux with address 0x70, channel 3.
3785 - CONFIG_ENV_IS_IN_DATAFLASH:
3787 Define this if you have a DataFlash memory device which you
3788 want to use for the environment.
3790 - CONFIG_ENV_OFFSET:
3794 These three #defines specify the offset and size of the
3795 environment area within the total memory of your DataFlash placed
3796 at the specified address.
3798 - CONFIG_ENV_IS_IN_SPI_FLASH:
3800 Define this if you have a SPI Flash memory device which you
3801 want to use for the environment.
3803 - CONFIG_ENV_OFFSET:
3806 These two #defines specify the offset and size of the
3807 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3808 aligned to an erase sector boundary.
3810 - CONFIG_ENV_SECT_SIZE:
3812 Define the SPI flash's sector size.
3814 - CONFIG_ENV_OFFSET_REDUND (optional):
3816 This setting describes a second storage area of CONFIG_ENV_SIZE
3817 size used to hold a redundant copy of the environment data, so
3818 that there is a valid backup copy in case there is a power failure
3819 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3820 aligned to an erase sector boundary.
3822 - CONFIG_ENV_SPI_BUS (optional):
3823 - CONFIG_ENV_SPI_CS (optional):
3825 Define the SPI bus and chip select. If not defined they will be 0.
3827 - CONFIG_ENV_SPI_MAX_HZ (optional):
3829 Define the SPI max work clock. If not defined then use 1MHz.
3831 - CONFIG_ENV_SPI_MODE (optional):
3833 Define the SPI work mode. If not defined then use SPI_MODE_3.
3835 - CONFIG_ENV_IS_IN_REMOTE:
3837 Define this if you have a remote memory space which you
3838 want to use for the local device's environment.
3843 These two #defines specify the address and size of the
3844 environment area within the remote memory space. The
3845 local device can get the environment from remote memory
3846 space by SRIO or PCIE links.
3848 BE CAREFUL! For some special cases, the local device can not use
3849 "saveenv" command. For example, the local device will get the
3850 environment stored in a remote NOR flash by SRIO or PCIE link,
3851 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3853 - CONFIG_ENV_IS_IN_NAND:
3855 Define this if you have a NAND device which you want to use
3856 for the environment.
3858 - CONFIG_ENV_OFFSET:
3861 These two #defines specify the offset and size of the environment
3862 area within the first NAND device. CONFIG_ENV_OFFSET must be
3863 aligned to an erase block boundary.
3865 - CONFIG_ENV_OFFSET_REDUND (optional):
3867 This setting describes a second storage area of CONFIG_ENV_SIZE
3868 size used to hold a redundant copy of the environment data, so
3869 that there is a valid backup copy in case there is a power failure
3870 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3871 aligned to an erase block boundary.
3873 - CONFIG_ENV_RANGE (optional):
3875 Specifies the length of the region in which the environment
3876 can be written. This should be a multiple of the NAND device's
3877 block size. Specifying a range with more erase blocks than
3878 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3879 the range to be avoided.
3881 - CONFIG_ENV_OFFSET_OOB (optional):
3883 Enables support for dynamically retrieving the offset of the
3884 environment from block zero's out-of-band data. The
3885 "nand env.oob" command can be used to record this offset.
3886 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3887 using CONFIG_ENV_OFFSET_OOB.
3889 - CONFIG_NAND_ENV_DST
3891 Defines address in RAM to which the nand_spl code should copy the
3892 environment. If redundant environment is used, it will be copied to
3893 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3895 - CONFIG_ENV_IS_IN_UBI:
3897 Define this if you have an UBI volume that you want to use for the
3898 environment. This has the benefit of wear-leveling the environment
3899 accesses, which is important on NAND.
3901 - CONFIG_ENV_UBI_PART:
3903 Define this to a string that is the mtd partition containing the UBI.
3905 - CONFIG_ENV_UBI_VOLUME:
3907 Define this to the name of the volume that you want to store the
3910 - CONFIG_ENV_UBI_VOLUME_REDUND:
3912 Define this to the name of another volume to store a second copy of
3913 the environment in. This will enable redundant environments in UBI.
3914 It is assumed that both volumes are in the same MTD partition.
3916 - CONFIG_UBI_SILENCE_MSG
3917 - CONFIG_UBIFS_SILENCE_MSG
3919 You will probably want to define these to avoid a really noisy system
3920 when storing the env in UBI.
3922 - CONFIG_ENV_IS_IN_FAT:
3923 Define this if you want to use the FAT file system for the environment.
3925 - FAT_ENV_INTERFACE:
3927 Define this to a string that is the name of the block device.
3929 - FAT_ENV_DEVICE_AND_PART:
3931 Define this to a string to specify the partition of the device. It can
3934 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3935 - "D:P": device D partition P. Error occurs if device D has no
3938 - "D" or "D:": device D partition 1 if device D has partition
3939 table, or the whole device D if has no partition
3941 - "D:auto": first partition in device D with bootable flag set.
3942 If none, first valid partition in device D. If no
3943 partition table then means device D.
3947 It's a string of the FAT file name. This file use to store the
3951 This should be defined. Otherwise it cannot save the environment file.
3953 - CONFIG_ENV_IS_IN_MMC:
3955 Define this if you have an MMC device which you want to use for the
3958 - CONFIG_SYS_MMC_ENV_DEV:
3960 Specifies which MMC device the environment is stored in.
3962 - CONFIG_SYS_MMC_ENV_PART (optional):
3964 Specifies which MMC partition the environment is stored in. If not
3965 set, defaults to partition 0, the user area. Common values might be
3966 1 (first MMC boot partition), 2 (second MMC boot partition).
3968 - CONFIG_ENV_OFFSET:
3971 These two #defines specify the offset and size of the environment
3972 area within the specified MMC device.
3974 If offset is positive (the usual case), it is treated as relative to
3975 the start of the MMC partition. If offset is negative, it is treated
3976 as relative to the end of the MMC partition. This can be useful if
3977 your board may be fitted with different MMC devices, which have
3978 different sizes for the MMC partitions, and you always want the
3979 environment placed at the very end of the partition, to leave the
3980 maximum possible space before it, to store other data.
3982 These two values are in units of bytes, but must be aligned to an
3983 MMC sector boundary.
3985 - CONFIG_ENV_OFFSET_REDUND (optional):
3987 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3988 hold a redundant copy of the environment data. This provides a
3989 valid backup copy in case the other copy is corrupted, e.g. due
3990 to a power failure during a "saveenv" operation.
3992 This value may also be positive or negative; this is handled in the
3993 same way as CONFIG_ENV_OFFSET.
3995 This value is also in units of bytes, but must also be aligned to
3996 an MMC sector boundary.
3998 - CONFIG_ENV_SIZE_REDUND (optional):
4000 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4001 set. If this value is set, it must be set to the same value as
4004 - CONFIG_SYS_SPI_INIT_OFFSET
4006 Defines offset to the initial SPI buffer area in DPRAM. The
4007 area is used at an early stage (ROM part) if the environment
4008 is configured to reside in the SPI EEPROM: We need a 520 byte
4009 scratch DPRAM area. It is used between the two initialization
4010 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4011 to be a good choice since it makes it far enough from the
4012 start of the data area as well as from the stack pointer.
4014 Please note that the environment is read-only until the monitor
4015 has been relocated to RAM and a RAM copy of the environment has been
4016 created; also, when using EEPROM you will have to use getenv_f()
4017 until then to read environment variables.
4019 The environment is protected by a CRC32 checksum. Before the monitor
4020 is relocated into RAM, as a result of a bad CRC you will be working
4021 with the compiled-in default environment - *silently*!!! [This is
4022 necessary, because the first environment variable we need is the
4023 "baudrate" setting for the console - if we have a bad CRC, we don't
4024 have any device yet where we could complain.]
4026 Note: once the monitor has been relocated, then it will complain if
4027 the default environment is used; a new CRC is computed as soon as you
4028 use the "saveenv" command to store a valid environment.
4030 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4031 Echo the inverted Ethernet link state to the fault LED.
4033 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4034 also needs to be defined.
4036 - CONFIG_SYS_FAULT_MII_ADDR:
4037 MII address of the PHY to check for the Ethernet link state.
4039 - CONFIG_NS16550_MIN_FUNCTIONS:
4040 Define this if you desire to only have use of the NS16550_init
4041 and NS16550_putc functions for the serial driver located at
4042 drivers/serial/ns16550.c. This option is useful for saving
4043 space for already greatly restricted images, including but not
4044 limited to NAND_SPL configurations.
4046 - CONFIG_DISPLAY_BOARDINFO
4047 Display information about the board that U-Boot is running on
4048 when U-Boot starts up. The board function checkboard() is called
4051 - CONFIG_DISPLAY_BOARDINFO_LATE
4052 Similar to the previous option, but display this information
4053 later, once stdio is running and output goes to the LCD, if
4056 - CONFIG_BOARD_SIZE_LIMIT:
4057 Maximum size of the U-Boot image. When defined, the
4058 build system checks that the actual size does not
4061 Low Level (hardware related) configuration options:
4062 ---------------------------------------------------
4064 - CONFIG_SYS_CACHELINE_SIZE:
4065 Cache Line Size of the CPU.
4067 - CONFIG_SYS_DEFAULT_IMMR:
4068 Default address of the IMMR after system reset.
4070 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4071 and RPXsuper) to be able to adjust the position of
4072 the IMMR register after a reset.
4074 - CONFIG_SYS_CCSRBAR_DEFAULT:
4075 Default (power-on reset) physical address of CCSR on Freescale
4078 - CONFIG_SYS_CCSRBAR:
4079 Virtual address of CCSR. On a 32-bit build, this is typically
4080 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4082 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4083 for cross-platform code that uses that macro instead.
4085 - CONFIG_SYS_CCSRBAR_PHYS:
4086 Physical address of CCSR. CCSR can be relocated to a new
4087 physical address, if desired. In this case, this macro should
4088 be set to that address. Otherwise, it should be set to the
4089 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4090 is typically relocated on 36-bit builds. It is recommended
4091 that this macro be defined via the _HIGH and _LOW macros:
4093 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4094 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4096 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4097 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4098 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4099 used in assembly code, so it must not contain typecasts or
4100 integer size suffixes (e.g. "ULL").
4102 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4103 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4104 used in assembly code, so it must not contain typecasts or
4105 integer size suffixes (e.g. "ULL").
4107 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4108 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4109 forced to a value that ensures that CCSR is not relocated.
4111 - Floppy Disk Support:
4112 CONFIG_SYS_FDC_DRIVE_NUMBER
4114 the default drive number (default value 0)
4116 CONFIG_SYS_ISA_IO_STRIDE
4118 defines the spacing between FDC chipset registers
4121 CONFIG_SYS_ISA_IO_OFFSET
4123 defines the offset of register from address. It
4124 depends on which part of the data bus is connected to
4125 the FDC chipset. (default value 0)
4127 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4128 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4131 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4132 fdc_hw_init() is called at the beginning of the FDC
4133 setup. fdc_hw_init() must be provided by the board
4134 source code. It is used to make hardware-dependent
4138 Most IDE controllers were designed to be connected with PCI
4139 interface. Only few of them were designed for AHB interface.
4140 When software is doing ATA command and data transfer to
4141 IDE devices through IDE-AHB controller, some additional
4142 registers accessing to these kind of IDE-AHB controller
4145 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4146 DO NOT CHANGE unless you know exactly what you're
4147 doing! (11-4) [MPC8xx/82xx systems only]
4149 - CONFIG_SYS_INIT_RAM_ADDR:
4151 Start address of memory area that can be used for
4152 initial data and stack; please note that this must be
4153 writable memory that is working WITHOUT special
4154 initialization, i. e. you CANNOT use normal RAM which
4155 will become available only after programming the
4156 memory controller and running certain initialization
4159 U-Boot uses the following memory types:
4160 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4161 - MPC824X: data cache
4162 - PPC4xx: data cache
4164 - CONFIG_SYS_GBL_DATA_OFFSET:
4166 Offset of the initial data structure in the memory
4167 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4168 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4169 data is located at the end of the available space
4170 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4171 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4172 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4173 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4176 On the MPC824X (or other systems that use the data
4177 cache for initial memory) the address chosen for
4178 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4179 point to an otherwise UNUSED address space between
4180 the top of RAM and the start of the PCI space.
4182 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4184 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4186 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4188 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4190 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4192 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4194 - CONFIG_SYS_OR_TIMING_SDRAM:
4197 - CONFIG_SYS_MAMR_PTA:
4198 periodic timer for refresh
4200 - CONFIG_SYS_DER: Debug Event Register (37-47)
4202 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4203 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4204 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4205 CONFIG_SYS_BR1_PRELIM:
4206 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4208 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4209 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4210 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4211 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4213 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4214 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4215 Machine Mode Register and Memory Periodic Timer
4216 Prescaler definitions (SDRAM timing)
4218 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4219 enable I2C microcode relocation patch (MPC8xx);
4220 define relocation offset in DPRAM [DSP2]
4222 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4223 enable SMC microcode relocation patch (MPC8xx);
4224 define relocation offset in DPRAM [SMC1]
4226 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4227 enable SPI microcode relocation patch (MPC8xx);
4228 define relocation offset in DPRAM [SCC4]
4230 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4231 Offset of the bootmode word in DPRAM used by post
4232 (Power On Self Tests). This definition overrides
4233 #define'd default value in commproc.h resp.
4236 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4237 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4238 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4239 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4240 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4241 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4242 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4243 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4244 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4246 - CONFIG_PCI_DISABLE_PCIE:
4247 Disable PCI-Express on systems where it is supported but not
4250 - CONFIG_PCI_ENUM_ONLY
4251 Only scan through and get the devices on the buses.
4252 Don't do any setup work, presumably because someone or
4253 something has already done it, and we don't need to do it
4254 a second time. Useful for platforms that are pre-booted
4255 by coreboot or similar.
4257 - CONFIG_PCI_INDIRECT_BRIDGE:
4258 Enable support for indirect PCI bridges.
4261 Chip has SRIO or not
4264 Board has SRIO 1 port available
4267 Board has SRIO 2 port available
4269 - CONFIG_SRIO_PCIE_BOOT_MASTER
4270 Board can support master function for Boot from SRIO and PCIE
4272 - CONFIG_SYS_SRIOn_MEM_VIRT:
4273 Virtual Address of SRIO port 'n' memory region
4275 - CONFIG_SYS_SRIOn_MEM_PHYS:
4276 Physical Address of SRIO port 'n' memory region
4278 - CONFIG_SYS_SRIOn_MEM_SIZE:
4279 Size of SRIO port 'n' memory region
4281 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4282 Defined to tell the NAND controller that the NAND chip is using
4284 Not all NAND drivers use this symbol.
4285 Example of drivers that use it:
4286 - drivers/mtd/nand/ndfc.c
4287 - drivers/mtd/nand/mxc_nand.c
4289 - CONFIG_SYS_NDFC_EBC0_CFG
4290 Sets the EBC0_CFG register for the NDFC. If not defined
4291 a default value will be used.
4294 Get DDR timing information from an I2C EEPROM. Common
4295 with pluggable memory modules such as SODIMMs
4298 I2C address of the SPD EEPROM
4300 - CONFIG_SYS_SPD_BUS_NUM
4301 If SPD EEPROM is on an I2C bus other than the first
4302 one, specify here. Note that the value must resolve
4303 to something your driver can deal with.
4305 - CONFIG_SYS_DDR_RAW_TIMING
4306 Get DDR timing information from other than SPD. Common with
4307 soldered DDR chips onboard without SPD. DDR raw timing
4308 parameters are extracted from datasheet and hard-coded into
4309 header files or board specific files.
4311 - CONFIG_FSL_DDR_INTERACTIVE
4312 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4314 - CONFIG_FSL_DDR_SYNC_REFRESH
4315 Enable sync of refresh for multiple controllers.
4317 - CONFIG_FSL_DDR_BIST
4318 Enable built-in memory test for Freescale DDR controllers.
4320 - CONFIG_SYS_83XX_DDR_USES_CS0
4321 Only for 83xx systems. If specified, then DDR should
4322 be configured using CS0 and CS1 instead of CS2 and CS3.
4324 - CONFIG_ETHER_ON_FEC[12]
4325 Define to enable FEC[12] on a 8xx series processor.
4327 - CONFIG_FEC[12]_PHY
4328 Define to the hardcoded PHY address which corresponds
4329 to the given FEC; i. e.
4330 #define CONFIG_FEC1_PHY 4
4331 means that the PHY with address 4 is connected to FEC1
4333 When set to -1, means to probe for first available.
4335 - CONFIG_FEC[12]_PHY_NORXERR
4336 The PHY does not have a RXERR line (RMII only).
4337 (so program the FEC to ignore it).
4340 Enable RMII mode for all FECs.
4341 Note that this is a global option, we can't
4342 have one FEC in standard MII mode and another in RMII mode.
4344 - CONFIG_CRC32_VERIFY
4345 Add a verify option to the crc32 command.
4348 => crc32 -v <address> <count> <crc32>
4350 Where address/count indicate a memory area
4351 and crc32 is the correct crc32 which the
4355 Add the "loopw" memory command. This only takes effect if
4356 the memory commands are activated globally (CONFIG_CMD_MEM).
4359 Add the "mdc" and "mwc" memory commands. These are cyclic
4364 This command will print 4 bytes (10,11,12,13) each 500 ms.
4366 => mwc.l 100 12345678 10
4367 This command will write 12345678 to address 100 all 10 ms.
4369 This only takes effect if the memory commands are activated
4370 globally (CONFIG_CMD_MEM).
4372 - CONFIG_SKIP_LOWLEVEL_INIT
4373 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4374 low level initializations (like setting up the memory
4375 controller) are omitted and/or U-Boot does not
4376 relocate itself into RAM.
4378 Normally this variable MUST NOT be defined. The only
4379 exception is when U-Boot is loaded (to RAM) by some
4380 other boot loader or by a debugger which performs
4381 these initializations itself.
4383 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4384 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4385 to be skipped. The normal CP15 init (such as enabling the
4386 instruction cache) is still performed.
4389 Modifies the behaviour of start.S when compiling a loader
4390 that is executed before the actual U-Boot. E.g. when
4391 compiling a NAND SPL.
4394 Modifies the behaviour of start.S when compiling a loader
4395 that is executed after the SPL and before the actual U-Boot.
4396 It is loaded by the SPL.
4398 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4399 Only for 85xx systems. If this variable is specified, the section
4400 .resetvec is not kept and the section .bootpg is placed in the
4401 previous 4k of the .text section.
4403 - CONFIG_ARCH_MAP_SYSMEM
4404 Generally U-Boot (and in particular the md command) uses
4405 effective address. It is therefore not necessary to regard
4406 U-Boot address as virtual addresses that need to be translated
4407 to physical addresses. However, sandbox requires this, since
4408 it maintains its own little RAM buffer which contains all
4409 addressable memory. This option causes some memory accesses
4410 to be mapped through map_sysmem() / unmap_sysmem().
4412 - CONFIG_X86_RESET_VECTOR
4413 If defined, the x86 reset vector code is included. This is not
4414 needed when U-Boot is running from Coreboot.
4416 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4417 Enables the RTC32K OSC on AM33xx based plattforms
4419 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4420 Option to disable subpage write in NAND driver
4421 driver that uses this:
4422 drivers/mtd/nand/davinci_nand.c
4424 Freescale QE/FMAN Firmware Support:
4425 -----------------------------------
4427 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4428 loading of "firmware", which is encoded in the QE firmware binary format.
4429 This firmware often needs to be loaded during U-Boot booting, so macros
4430 are used to identify the storage device (NOR flash, SPI, etc) and the address
4433 - CONFIG_SYS_FMAN_FW_ADDR
4434 The address in the storage device where the FMAN microcode is located. The
4435 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4438 - CONFIG_SYS_QE_FW_ADDR
4439 The address in the storage device where the QE microcode is located. The
4440 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4443 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4444 The maximum possible size of the firmware. The firmware binary format
4445 has a field that specifies the actual size of the firmware, but it
4446 might not be possible to read any part of the firmware unless some
4447 local storage is allocated to hold the entire firmware first.
4449 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4450 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4451 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4452 virtual address in NOR flash.
4454 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4455 Specifies that QE/FMAN firmware is located in NAND flash.
4456 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4458 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4459 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4460 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4462 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4463 Specifies that QE/FMAN firmware is located in the remote (master)
4464 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4465 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4466 window->master inbound window->master LAW->the ucode address in
4467 master's memory space.
4469 Freescale Layerscape Management Complex Firmware Support:
4470 ---------------------------------------------------------
4471 The Freescale Layerscape Management Complex (MC) supports the loading of
4473 This firmware often needs to be loaded during U-Boot booting, so macros
4474 are used to identify the storage device (NOR flash, SPI, etc) and the address
4477 - CONFIG_FSL_MC_ENET
4478 Enable the MC driver for Layerscape SoCs.
4480 Freescale Layerscape Debug Server Support:
4481 -------------------------------------------
4482 The Freescale Layerscape Debug Server Support supports the loading of
4483 "Debug Server firmware" and triggering SP boot-rom.
4484 This firmware often needs to be loaded during U-Boot booting.
4486 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4487 Define alignment of reserved memory MC requires
4492 In order to achieve reproducible builds, timestamps used in the U-Boot build
4493 process have to be set to a fixed value.
4495 This is done using the SOURCE_DATE_EPOCH environment variable.
4496 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4497 option for U-Boot or an environment variable in U-Boot.
4499 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4501 Building the Software:
4502 ======================
4504 Building U-Boot has been tested in several native build environments
4505 and in many different cross environments. Of course we cannot support
4506 all possibly existing versions of cross development tools in all
4507 (potentially obsolete) versions. In case of tool chain problems we
4508 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4509 which is extensively used to build and test U-Boot.
4511 If you are not using a native environment, it is assumed that you
4512 have GNU cross compiling tools available in your path. In this case,
4513 you must set the environment variable CROSS_COMPILE in your shell.
4514 Note that no changes to the Makefile or any other source files are
4515 necessary. For example using the ELDK on a 4xx CPU, please enter:
4517 $ CROSS_COMPILE=ppc_4xx-
4518 $ export CROSS_COMPILE
4520 Note: If you wish to generate Windows versions of the utilities in
4521 the tools directory you can use the MinGW toolchain
4522 (http://www.mingw.org). Set your HOST tools to the MinGW
4523 toolchain and execute 'make tools'. For example:
4525 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4527 Binaries such as tools/mkimage.exe will be created which can
4528 be executed on computers running Windows.
4530 U-Boot is intended to be simple to build. After installing the
4531 sources you must configure U-Boot for one specific board type. This
4536 where "NAME_defconfig" is the name of one of the existing configu-
4537 rations; see boards.cfg for supported names.
4539 Note: for some board special configuration names may exist; check if
4540 additional information is available from the board vendor; for
4541 instance, the TQM823L systems are available without (standard)
4542 or with LCD support. You can select such additional "features"
4543 when choosing the configuration, i. e.
4545 make TQM823L_defconfig
4546 - will configure for a plain TQM823L, i. e. no LCD support
4548 make TQM823L_LCD_defconfig
4549 - will configure for a TQM823L with U-Boot console on LCD
4554 Finally, type "make all", and you should get some working U-Boot
4555 images ready for download to / installation on your system:
4557 - "u-boot.bin" is a raw binary image
4558 - "u-boot" is an image in ELF binary format
4559 - "u-boot.srec" is in Motorola S-Record format
4561 By default the build is performed locally and the objects are saved
4562 in the source directory. One of the two methods can be used to change
4563 this behavior and build U-Boot to some external directory:
4565 1. Add O= to the make command line invocations:
4567 make O=/tmp/build distclean
4568 make O=/tmp/build NAME_defconfig
4569 make O=/tmp/build all
4571 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4573 export KBUILD_OUTPUT=/tmp/build
4578 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4582 Please be aware that the Makefiles assume you are using GNU make, so
4583 for instance on NetBSD you might need to use "gmake" instead of
4587 If the system board that you have is not listed, then you will need
4588 to port U-Boot to your hardware platform. To do this, follow these
4591 1. Create a new directory to hold your board specific code. Add any
4592 files you need. In your board directory, you will need at least
4593 the "Makefile" and a "<board>.c".
4594 2. Create a new configuration file "include/configs/<board>.h" for
4596 3. If you're porting U-Boot to a new CPU, then also create a new
4597 directory to hold your CPU specific code. Add any files you need.
4598 4. Run "make <board>_defconfig" with your new name.
4599 5. Type "make", and you should get a working "u-boot.srec" file
4600 to be installed on your target system.
4601 6. Debug and solve any problems that might arise.
4602 [Of course, this last step is much harder than it sounds.]
4605 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4606 ==============================================================
4608 If you have modified U-Boot sources (for instance added a new board
4609 or support for new devices, a new CPU, etc.) you are expected to
4610 provide feedback to the other developers. The feedback normally takes
4611 the form of a "patch", i. e. a context diff against a certain (latest
4612 official or latest in the git repository) version of U-Boot sources.
4614 But before you submit such a patch, please verify that your modifi-
4615 cation did not break existing code. At least make sure that *ALL* of
4616 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4617 just run the buildman script (tools/buildman/buildman), which will
4618 configure and build U-Boot for ALL supported system. Be warned, this
4619 will take a while. Please see the buildman README, or run 'buildman -H'
4623 See also "U-Boot Porting Guide" below.
4626 Monitor Commands - Overview:
4627 ============================
4629 go - start application at address 'addr'
4630 run - run commands in an environment variable
4631 bootm - boot application image from memory
4632 bootp - boot image via network using BootP/TFTP protocol
4633 bootz - boot zImage from memory
4634 tftpboot- boot image via network using TFTP protocol
4635 and env variables "ipaddr" and "serverip"
4636 (and eventually "gatewayip")
4637 tftpput - upload a file via network using TFTP protocol
4638 rarpboot- boot image via network using RARP/TFTP protocol
4639 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4640 loads - load S-Record file over serial line
4641 loadb - load binary file over serial line (kermit mode)
4643 mm - memory modify (auto-incrementing)
4644 nm - memory modify (constant address)
4645 mw - memory write (fill)
4647 cmp - memory compare
4648 crc32 - checksum calculation
4649 i2c - I2C sub-system
4650 sspi - SPI utility commands
4651 base - print or set address offset
4652 printenv- print environment variables
4653 setenv - set environment variables
4654 saveenv - save environment variables to persistent storage
4655 protect - enable or disable FLASH write protection
4656 erase - erase FLASH memory
4657 flinfo - print FLASH memory information
4658 nand - NAND memory operations (see doc/README.nand)
4659 bdinfo - print Board Info structure
4660 iminfo - print header information for application image
4661 coninfo - print console devices and informations
4662 ide - IDE sub-system
4663 loop - infinite loop on address range
4664 loopw - infinite write loop on address range
4665 mtest - simple RAM test
4666 icache - enable or disable instruction cache
4667 dcache - enable or disable data cache
4668 reset - Perform RESET of the CPU
4669 echo - echo args to console
4670 version - print monitor version
4671 help - print online help
4672 ? - alias for 'help'
4675 Monitor Commands - Detailed Description:
4676 ========================================
4680 For now: just type "help <command>".
4683 Environment Variables:
4684 ======================
4686 U-Boot supports user configuration using Environment Variables which
4687 can be made persistent by saving to Flash memory.
4689 Environment Variables are set using "setenv", printed using
4690 "printenv", and saved to Flash using "saveenv". Using "setenv"
4691 without a value can be used to delete a variable from the
4692 environment. As long as you don't save the environment you are
4693 working with an in-memory copy. In case the Flash area containing the
4694 environment is erased by accident, a default environment is provided.
4696 Some configuration options can be set using Environment Variables.
4698 List of environment variables (most likely not complete):
4700 baudrate - see CONFIG_BAUDRATE
4702 bootdelay - see CONFIG_BOOTDELAY
4704 bootcmd - see CONFIG_BOOTCOMMAND
4706 bootargs - Boot arguments when booting an RTOS image
4708 bootfile - Name of the image to load with TFTP
4710 bootm_low - Memory range available for image processing in the bootm
4711 command can be restricted. This variable is given as
4712 a hexadecimal number and defines lowest address allowed
4713 for use by the bootm command. See also "bootm_size"
4714 environment variable. Address defined by "bootm_low" is
4715 also the base of the initial memory mapping for the Linux
4716 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4719 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4720 This variable is given as a hexadecimal number and it
4721 defines the size of the memory region starting at base
4722 address bootm_low that is accessible by the Linux kernel
4723 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4724 as the default value if it is defined, and bootm_size is
4727 bootm_size - Memory range available for image processing in the bootm
4728 command can be restricted. This variable is given as
4729 a hexadecimal number and defines the size of the region
4730 allowed for use by the bootm command. See also "bootm_low"
4731 environment variable.
4733 updatefile - Location of the software update file on a TFTP server, used
4734 by the automatic software update feature. Please refer to
4735 documentation in doc/README.update for more details.
4737 autoload - if set to "no" (any string beginning with 'n'),
4738 "bootp" will just load perform a lookup of the
4739 configuration from the BOOTP server, but not try to
4740 load any image using TFTP
4742 autostart - if set to "yes", an image loaded using the "bootp",
4743 "rarpboot", "tftpboot" or "diskboot" commands will
4744 be automatically started (by internally calling
4747 If set to "no", a standalone image passed to the
4748 "bootm" command will be copied to the load address
4749 (and eventually uncompressed), but NOT be started.
4750 This can be used to load and uncompress arbitrary
4753 fdt_high - if set this restricts the maximum address that the
4754 flattened device tree will be copied into upon boot.
4755 For example, if you have a system with 1 GB memory
4756 at physical address 0x10000000, while Linux kernel
4757 only recognizes the first 704 MB as low memory, you
4758 may need to set fdt_high as 0x3C000000 to have the
4759 device tree blob be copied to the maximum address
4760 of the 704 MB low memory, so that Linux kernel can
4761 access it during the boot procedure.
4763 If this is set to the special value 0xFFFFFFFF then
4764 the fdt will not be copied at all on boot. For this
4765 to work it must reside in writable memory, have
4766 sufficient padding on the end of it for u-boot to
4767 add the information it needs into it, and the memory
4768 must be accessible by the kernel.
4770 fdtcontroladdr- if set this is the address of the control flattened
4771 device tree used by U-Boot when CONFIG_OF_CONTROL is
4774 i2cfast - (PPC405GP|PPC405EP only)
4775 if set to 'y' configures Linux I2C driver for fast
4776 mode (400kHZ). This environment variable is used in
4777 initialization code. So, for changes to be effective
4778 it must be saved and board must be reset.
4780 initrd_high - restrict positioning of initrd images:
4781 If this variable is not set, initrd images will be
4782 copied to the highest possible address in RAM; this
4783 is usually what you want since it allows for
4784 maximum initrd size. If for some reason you want to
4785 make sure that the initrd image is loaded below the
4786 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4787 variable to a value of "no" or "off" or "0".
4788 Alternatively, you can set it to a maximum upper
4789 address to use (U-Boot will still check that it
4790 does not overwrite the U-Boot stack and data).
4792 For instance, when you have a system with 16 MB
4793 RAM, and want to reserve 4 MB from use by Linux,
4794 you can do this by adding "mem=12M" to the value of
4795 the "bootargs" variable. However, now you must make
4796 sure that the initrd image is placed in the first
4797 12 MB as well - this can be done with
4799 setenv initrd_high 00c00000
4801 If you set initrd_high to 0xFFFFFFFF, this is an
4802 indication to U-Boot that all addresses are legal
4803 for the Linux kernel, including addresses in flash
4804 memory. In this case U-Boot will NOT COPY the
4805 ramdisk at all. This may be useful to reduce the
4806 boot time on your system, but requires that this
4807 feature is supported by your Linux kernel.
4809 ipaddr - IP address; needed for tftpboot command
4811 loadaddr - Default load address for commands like "bootp",
4812 "rarpboot", "tftpboot", "loadb" or "diskboot"
4814 loads_echo - see CONFIG_LOADS_ECHO
4816 serverip - TFTP server IP address; needed for tftpboot command
4818 bootretry - see CONFIG_BOOT_RETRY_TIME
4820 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4822 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4824 ethprime - controls which interface is used first.
4826 ethact - controls which interface is currently active.
4827 For example you can do the following
4829 => setenv ethact FEC
4830 => ping 192.168.0.1 # traffic sent on FEC
4831 => setenv ethact SCC
4832 => ping 10.0.0.1 # traffic sent on SCC
4834 ethrotate - When set to "no" U-Boot does not go through all
4835 available network interfaces.
4836 It just stays at the currently selected interface.
4838 netretry - When set to "no" each network operation will
4839 either succeed or fail without retrying.
4840 When set to "once" the network operation will
4841 fail when all the available network interfaces
4842 are tried once without success.
4843 Useful on scripts which control the retry operation
4846 npe_ucode - set load address for the NPE microcode
4848 silent_linux - If set then Linux will be told to boot silently, by
4849 changing the console to be empty. If "yes" it will be
4850 made silent. If "no" it will not be made silent. If
4851 unset, then it will be made silent if the U-Boot console
4854 tftpsrcp - If this is set, the value is used for TFTP's
4857 tftpdstp - If this is set, the value is used for TFTP's UDP
4858 destination port instead of the Well Know Port 69.
4860 tftpblocksize - Block size to use for TFTP transfers; if not set,
4861 we use the TFTP server's default block size
4863 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4864 seconds, minimum value is 1000 = 1 second). Defines
4865 when a packet is considered to be lost so it has to
4866 be retransmitted. The default is 5000 = 5 seconds.
4867 Lowering this value may make downloads succeed
4868 faster in networks with high packet loss rates or
4869 with unreliable TFTP servers.
4871 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4872 unit, minimum value = 0). Defines how many timeouts
4873 can happen during a single file transfer before that
4874 transfer is aborted. The default is 10, and 0 means
4875 'no timeouts allowed'. Increasing this value may help
4876 downloads succeed with high packet loss rates, or with
4877 unreliable TFTP servers or client hardware.
4879 vlan - When set to a value < 4095 the traffic over
4880 Ethernet is encapsulated/received over 802.1q
4883 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4884 Unsigned value, in milliseconds. If not set, the period will
4885 be either the default (28000), or a value based on
4886 CONFIG_NET_RETRY_COUNT, if defined. This value has
4887 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4889 The following image location variables contain the location of images
4890 used in booting. The "Image" column gives the role of the image and is
4891 not an environment variable name. The other columns are environment
4892 variable names. "File Name" gives the name of the file on a TFTP
4893 server, "RAM Address" gives the location in RAM the image will be
4894 loaded to, and "Flash Location" gives the image's address in NOR
4895 flash or offset in NAND flash.
4897 *Note* - these variables don't have to be defined for all boards, some
4898 boards currently use other variables for these purposes, and some
4899 boards use these variables for other purposes.
4901 Image File Name RAM Address Flash Location
4902 ----- --------- ----------- --------------
4903 u-boot u-boot u-boot_addr_r u-boot_addr
4904 Linux kernel bootfile kernel_addr_r kernel_addr
4905 device tree blob fdtfile fdt_addr_r fdt_addr
4906 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4908 The following environment variables may be used and automatically
4909 updated by the network boot commands ("bootp" and "rarpboot"),
4910 depending the information provided by your boot server:
4912 bootfile - see above
4913 dnsip - IP address of your Domain Name Server
4914 dnsip2 - IP address of your secondary Domain Name Server
4915 gatewayip - IP address of the Gateway (Router) to use
4916 hostname - Target hostname
4918 netmask - Subnet Mask
4919 rootpath - Pathname of the root filesystem on the NFS server
4920 serverip - see above
4923 There are two special Environment Variables:
4925 serial# - contains hardware identification information such
4926 as type string and/or serial number
4927 ethaddr - Ethernet address
4929 These variables can be set only once (usually during manufacturing of
4930 the board). U-Boot refuses to delete or overwrite these variables
4931 once they have been set once.
4934 Further special Environment Variables:
4936 ver - Contains the U-Boot version string as printed
4937 with the "version" command. This variable is
4938 readonly (see CONFIG_VERSION_VARIABLE).
4941 Please note that changes to some configuration parameters may take
4942 only effect after the next boot (yes, that's just like Windoze :-).
4945 Callback functions for environment variables:
4946 ---------------------------------------------
4948 For some environment variables, the behavior of u-boot needs to change
4949 when their values are changed. This functionality allows functions to
4950 be associated with arbitrary variables. On creation, overwrite, or
4951 deletion, the callback will provide the opportunity for some side
4952 effect to happen or for the change to be rejected.
4954 The callbacks are named and associated with a function using the
4955 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4957 These callbacks are associated with variables in one of two ways. The
4958 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4959 in the board configuration to a string that defines a list of
4960 associations. The list must be in the following format:
4962 entry = variable_name[:callback_name]
4965 If the callback name is not specified, then the callback is deleted.
4966 Spaces are also allowed anywhere in the list.
4968 Callbacks can also be associated by defining the ".callbacks" variable
4969 with the same list format above. Any association in ".callbacks" will
4970 override any association in the static list. You can define
4971 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4972 ".callbacks" environment variable in the default or embedded environment.
4974 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4975 regular expression. This allows multiple variables to be connected to
4976 the same callback without explicitly listing them all out.
4979 Command Line Parsing:
4980 =====================
4982 There are two different command line parsers available with U-Boot:
4983 the old "simple" one, and the much more powerful "hush" shell:
4985 Old, simple command line parser:
4986 --------------------------------
4988 - supports environment variables (through setenv / saveenv commands)
4989 - several commands on one line, separated by ';'
4990 - variable substitution using "... ${name} ..." syntax
4991 - special characters ('$', ';') can be escaped by prefixing with '\',
4993 setenv bootcmd bootm \${address}
4994 - You can also escape text by enclosing in single apostrophes, for example:
4995 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5000 - similar to Bourne shell, with control structures like
5001 if...then...else...fi, for...do...done; while...do...done,
5002 until...do...done, ...
5003 - supports environment ("global") variables (through setenv / saveenv
5004 commands) and local shell variables (through standard shell syntax
5005 "name=value"); only environment variables can be used with "run"
5011 (1) If a command line (or an environment variable executed by a "run"
5012 command) contains several commands separated by semicolon, and
5013 one of these commands fails, then the remaining commands will be
5016 (2) If you execute several variables with one call to run (i. e.
5017 calling run with a list of variables as arguments), any failing
5018 command will cause "run" to terminate, i. e. the remaining
5019 variables are not executed.
5021 Note for Redundant Ethernet Interfaces:
5022 =======================================
5024 Some boards come with redundant Ethernet interfaces; U-Boot supports
5025 such configurations and is capable of automatic selection of a
5026 "working" interface when needed. MAC assignment works as follows:
5028 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5029 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5030 "eth1addr" (=>eth1), "eth2addr", ...
5032 If the network interface stores some valid MAC address (for instance
5033 in SROM), this is used as default address if there is NO correspon-
5034 ding setting in the environment; if the corresponding environment
5035 variable is set, this overrides the settings in the card; that means:
5037 o If the SROM has a valid MAC address, and there is no address in the
5038 environment, the SROM's address is used.
5040 o If there is no valid address in the SROM, and a definition in the
5041 environment exists, then the value from the environment variable is
5044 o If both the SROM and the environment contain a MAC address, and
5045 both addresses are the same, this MAC address is used.
5047 o If both the SROM and the environment contain a MAC address, and the
5048 addresses differ, the value from the environment is used and a
5051 o If neither SROM nor the environment contain a MAC address, an error
5052 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5053 a random, locally-assigned MAC is used.
5055 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5056 will be programmed into hardware as part of the initialization process. This
5057 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5058 The naming convention is as follows:
5059 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5064 U-Boot is capable of booting (and performing other auxiliary operations on)
5065 images in two formats:
5067 New uImage format (FIT)
5068 -----------------------
5070 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5071 to Flattened Device Tree). It allows the use of images with multiple
5072 components (several kernels, ramdisks, etc.), with contents protected by
5073 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5079 Old image format is based on binary files which can be basically anything,
5080 preceded by a special header; see the definitions in include/image.h for
5081 details; basically, the header defines the following image properties:
5083 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5084 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5085 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5086 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5088 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5089 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5090 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5091 * Compression Type (uncompressed, gzip, bzip2)
5097 The header is marked by a special Magic Number, and both the header
5098 and the data portions of the image are secured against corruption by
5105 Although U-Boot should support any OS or standalone application
5106 easily, the main focus has always been on Linux during the design of
5109 U-Boot includes many features that so far have been part of some
5110 special "boot loader" code within the Linux kernel. Also, any
5111 "initrd" images to be used are no longer part of one big Linux image;
5112 instead, kernel and "initrd" are separate images. This implementation
5113 serves several purposes:
5115 - the same features can be used for other OS or standalone
5116 applications (for instance: using compressed images to reduce the
5117 Flash memory footprint)
5119 - it becomes much easier to port new Linux kernel versions because
5120 lots of low-level, hardware dependent stuff are done by U-Boot
5122 - the same Linux kernel image can now be used with different "initrd"
5123 images; of course this also means that different kernel images can
5124 be run with the same "initrd". This makes testing easier (you don't
5125 have to build a new "zImage.initrd" Linux image when you just
5126 change a file in your "initrd"). Also, a field-upgrade of the
5127 software is easier now.
5133 Porting Linux to U-Boot based systems:
5134 ---------------------------------------
5136 U-Boot cannot save you from doing all the necessary modifications to
5137 configure the Linux device drivers for use with your target hardware
5138 (no, we don't intend to provide a full virtual machine interface to
5141 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5143 Just make sure your machine specific header file (for instance
5144 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5145 Information structure as we define in include/asm-<arch>/u-boot.h,
5146 and make sure that your definition of IMAP_ADDR uses the same value
5147 as your U-Boot configuration in CONFIG_SYS_IMMR.
5149 Note that U-Boot now has a driver model, a unified model for drivers.
5150 If you are adding a new driver, plumb it into driver model. If there
5151 is no uclass available, you are encouraged to create one. See
5155 Configuring the Linux kernel:
5156 -----------------------------
5158 No specific requirements for U-Boot. Make sure you have some root
5159 device (initial ramdisk, NFS) for your target system.
5162 Building a Linux Image:
5163 -----------------------
5165 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5166 not used. If you use recent kernel source, a new build target
5167 "uImage" will exist which automatically builds an image usable by
5168 U-Boot. Most older kernels also have support for a "pImage" target,
5169 which was introduced for our predecessor project PPCBoot and uses a
5170 100% compatible format.
5174 make TQM850L_defconfig
5179 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5180 encapsulate a compressed Linux kernel image with header information,
5181 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5183 * build a standard "vmlinux" kernel image (in ELF binary format):
5185 * convert the kernel into a raw binary image:
5187 ${CROSS_COMPILE}-objcopy -O binary \
5188 -R .note -R .comment \
5189 -S vmlinux linux.bin
5191 * compress the binary image:
5195 * package compressed binary image for U-Boot:
5197 mkimage -A ppc -O linux -T kernel -C gzip \
5198 -a 0 -e 0 -n "Linux Kernel Image" \
5199 -d linux.bin.gz uImage
5202 The "mkimage" tool can also be used to create ramdisk images for use
5203 with U-Boot, either separated from the Linux kernel image, or
5204 combined into one file. "mkimage" encapsulates the images with a 64
5205 byte header containing information about target architecture,
5206 operating system, image type, compression method, entry points, time
5207 stamp, CRC32 checksums, etc.
5209 "mkimage" can be called in two ways: to verify existing images and
5210 print the header information, or to build new images.
5212 In the first form (with "-l" option) mkimage lists the information
5213 contained in the header of an existing U-Boot image; this includes
5214 checksum verification:
5216 tools/mkimage -l image
5217 -l ==> list image header information
5219 The second form (with "-d" option) is used to build a U-Boot image
5220 from a "data file" which is used as image payload:
5222 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5223 -n name -d data_file image
5224 -A ==> set architecture to 'arch'
5225 -O ==> set operating system to 'os'
5226 -T ==> set image type to 'type'
5227 -C ==> set compression type 'comp'
5228 -a ==> set load address to 'addr' (hex)
5229 -e ==> set entry point to 'ep' (hex)
5230 -n ==> set image name to 'name'
5231 -d ==> use image data from 'datafile'
5233 Right now, all Linux kernels for PowerPC systems use the same load
5234 address (0x00000000), but the entry point address depends on the
5237 - 2.2.x kernels have the entry point at 0x0000000C,
5238 - 2.3.x and later kernels have the entry point at 0x00000000.
5240 So a typical call to build a U-Boot image would read:
5242 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5243 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5244 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5245 > examples/uImage.TQM850L
5246 Image Name: 2.4.4 kernel for TQM850L
5247 Created: Wed Jul 19 02:34:59 2000
5248 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5249 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5250 Load Address: 0x00000000
5251 Entry Point: 0x00000000
5253 To verify the contents of the image (or check for corruption):
5255 -> tools/mkimage -l examples/uImage.TQM850L
5256 Image Name: 2.4.4 kernel for TQM850L
5257 Created: Wed Jul 19 02:34:59 2000
5258 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5259 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5260 Load Address: 0x00000000
5261 Entry Point: 0x00000000
5263 NOTE: for embedded systems where boot time is critical you can trade
5264 speed for memory and install an UNCOMPRESSED image instead: this
5265 needs more space in Flash, but boots much faster since it does not
5266 need to be uncompressed:
5268 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5269 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5270 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5271 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5272 > examples/uImage.TQM850L-uncompressed
5273 Image Name: 2.4.4 kernel for TQM850L
5274 Created: Wed Jul 19 02:34:59 2000
5275 Image Type: PowerPC Linux Kernel Image (uncompressed)
5276 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5277 Load Address: 0x00000000
5278 Entry Point: 0x00000000
5281 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5282 when your kernel is intended to use an initial ramdisk:
5284 -> tools/mkimage -n 'Simple Ramdisk Image' \
5285 > -A ppc -O linux -T ramdisk -C gzip \
5286 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5287 Image Name: Simple Ramdisk Image
5288 Created: Wed Jan 12 14:01:50 2000
5289 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5290 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5291 Load Address: 0x00000000
5292 Entry Point: 0x00000000
5294 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5295 option performs the converse operation of the mkimage's second form (the "-d"
5296 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5299 tools/dumpimage -i image -T type -p position data_file
5300 -i ==> extract from the 'image' a specific 'data_file'
5301 -T ==> set image type to 'type'
5302 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5305 Installing a Linux Image:
5306 -------------------------
5308 To downloading a U-Boot image over the serial (console) interface,
5309 you must convert the image to S-Record format:
5311 objcopy -I binary -O srec examples/image examples/image.srec
5313 The 'objcopy' does not understand the information in the U-Boot
5314 image header, so the resulting S-Record file will be relative to
5315 address 0x00000000. To load it to a given address, you need to
5316 specify the target address as 'offset' parameter with the 'loads'
5319 Example: install the image to address 0x40100000 (which on the
5320 TQM8xxL is in the first Flash bank):
5322 => erase 40100000 401FFFFF
5328 ## Ready for S-Record download ...
5329 ~>examples/image.srec
5330 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5332 15989 15990 15991 15992
5333 [file transfer complete]
5335 ## Start Addr = 0x00000000
5338 You can check the success of the download using the 'iminfo' command;
5339 this includes a checksum verification so you can be sure no data
5340 corruption happened:
5344 ## Checking Image at 40100000 ...
5345 Image Name: 2.2.13 for initrd on TQM850L
5346 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5347 Data Size: 335725 Bytes = 327 kB = 0 MB
5348 Load Address: 00000000
5349 Entry Point: 0000000c
5350 Verifying Checksum ... OK
5356 The "bootm" command is used to boot an application that is stored in
5357 memory (RAM or Flash). In case of a Linux kernel image, the contents
5358 of the "bootargs" environment variable is passed to the kernel as
5359 parameters. You can check and modify this variable using the
5360 "printenv" and "setenv" commands:
5363 => printenv bootargs
5364 bootargs=root=/dev/ram
5366 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5368 => printenv bootargs
5369 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5372 ## Booting Linux kernel at 40020000 ...
5373 Image Name: 2.2.13 for NFS on TQM850L
5374 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5375 Data Size: 381681 Bytes = 372 kB = 0 MB
5376 Load Address: 00000000
5377 Entry Point: 0000000c
5378 Verifying Checksum ... OK
5379 Uncompressing Kernel Image ... OK
5380 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
5381 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5382 time_init: decrementer frequency = 187500000/60
5383 Calibrating delay loop... 49.77 BogoMIPS
5384 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5387 If you want to boot a Linux kernel with initial RAM disk, you pass
5388 the memory addresses of both the kernel and the initrd image (PPBCOOT
5389 format!) to the "bootm" command:
5391 => imi 40100000 40200000
5393 ## Checking Image at 40100000 ...
5394 Image Name: 2.2.13 for initrd on TQM850L
5395 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5396 Data Size: 335725 Bytes = 327 kB = 0 MB
5397 Load Address: 00000000
5398 Entry Point: 0000000c
5399 Verifying Checksum ... OK
5401 ## Checking Image at 40200000 ...
5402 Image Name: Simple Ramdisk Image
5403 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5404 Data Size: 566530 Bytes = 553 kB = 0 MB
5405 Load Address: 00000000
5406 Entry Point: 00000000
5407 Verifying Checksum ... OK
5409 => bootm 40100000 40200000
5410 ## Booting Linux kernel at 40100000 ...
5411 Image Name: 2.2.13 for initrd on TQM850L
5412 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5413 Data Size: 335725 Bytes = 327 kB = 0 MB
5414 Load Address: 00000000
5415 Entry Point: 0000000c
5416 Verifying Checksum ... OK
5417 Uncompressing Kernel Image ... OK
5418 ## Loading RAMDisk Image at 40200000 ...
5419 Image Name: Simple Ramdisk Image
5420 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5421 Data Size: 566530 Bytes = 553 kB = 0 MB
5422 Load Address: 00000000
5423 Entry Point: 00000000
5424 Verifying Checksum ... OK
5425 Loading Ramdisk ... OK
5426 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
5427 Boot arguments: root=/dev/ram
5428 time_init: decrementer frequency = 187500000/60
5429 Calibrating delay loop... 49.77 BogoMIPS
5431 RAMDISK: Compressed image found at block 0
5432 VFS: Mounted root (ext2 filesystem).
5436 Boot Linux and pass a flat device tree:
5439 First, U-Boot must be compiled with the appropriate defines. See the section
5440 titled "Linux Kernel Interface" above for a more in depth explanation. The
5441 following is an example of how to start a kernel and pass an updated
5447 oft=oftrees/mpc8540ads.dtb
5448 => tftp $oftaddr $oft
5449 Speed: 1000, full duplex
5451 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5452 Filename 'oftrees/mpc8540ads.dtb'.
5453 Load address: 0x300000
5456 Bytes transferred = 4106 (100a hex)
5457 => tftp $loadaddr $bootfile
5458 Speed: 1000, full duplex
5460 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5462 Load address: 0x200000
5463 Loading:############
5465 Bytes transferred = 1029407 (fb51f hex)
5470 => bootm $loadaddr - $oftaddr
5471 ## Booting image at 00200000 ...
5472 Image Name: Linux-2.6.17-dirty
5473 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5474 Data Size: 1029343 Bytes = 1005.2 kB
5475 Load Address: 00000000
5476 Entry Point: 00000000
5477 Verifying Checksum ... OK
5478 Uncompressing Kernel Image ... OK
5479 Booting using flat device tree at 0x300000
5480 Using MPC85xx ADS machine description
5481 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5485 More About U-Boot Image Types:
5486 ------------------------------
5488 U-Boot supports the following image types:
5490 "Standalone Programs" are directly runnable in the environment
5491 provided by U-Boot; it is expected that (if they behave
5492 well) you can continue to work in U-Boot after return from
5493 the Standalone Program.
5494 "OS Kernel Images" are usually images of some Embedded OS which
5495 will take over control completely. Usually these programs
5496 will install their own set of exception handlers, device
5497 drivers, set up the MMU, etc. - this means, that you cannot
5498 expect to re-enter U-Boot except by resetting the CPU.
5499 "RAMDisk Images" are more or less just data blocks, and their
5500 parameters (address, size) are passed to an OS kernel that is
5502 "Multi-File Images" contain several images, typically an OS
5503 (Linux) kernel image and one or more data images like
5504 RAMDisks. This construct is useful for instance when you want
5505 to boot over the network using BOOTP etc., where the boot
5506 server provides just a single image file, but you want to get
5507 for instance an OS kernel and a RAMDisk image.
5509 "Multi-File Images" start with a list of image sizes, each
5510 image size (in bytes) specified by an "uint32_t" in network
5511 byte order. This list is terminated by an "(uint32_t)0".
5512 Immediately after the terminating 0 follow the images, one by
5513 one, all aligned on "uint32_t" boundaries (size rounded up to
5514 a multiple of 4 bytes).
5516 "Firmware Images" are binary images containing firmware (like
5517 U-Boot or FPGA images) which usually will be programmed to
5520 "Script files" are command sequences that will be executed by
5521 U-Boot's command interpreter; this feature is especially
5522 useful when you configure U-Boot to use a real shell (hush)
5523 as command interpreter.
5525 Booting the Linux zImage:
5526 -------------------------
5528 On some platforms, it's possible to boot Linux zImage. This is done
5529 using the "bootz" command. The syntax of "bootz" command is the same
5530 as the syntax of "bootm" command.
5532 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5533 kernel with raw initrd images. The syntax is slightly different, the
5534 address of the initrd must be augmented by it's size, in the following
5535 format: "<initrd addres>:<initrd size>".
5541 One of the features of U-Boot is that you can dynamically load and
5542 run "standalone" applications, which can use some resources of
5543 U-Boot like console I/O functions or interrupt services.
5545 Two simple examples are included with the sources:
5550 'examples/hello_world.c' contains a small "Hello World" Demo
5551 application; it is automatically compiled when you build U-Boot.
5552 It's configured to run at address 0x00040004, so you can play with it
5556 ## Ready for S-Record download ...
5557 ~>examples/hello_world.srec
5558 1 2 3 4 5 6 7 8 9 10 11 ...
5559 [file transfer complete]
5561 ## Start Addr = 0x00040004
5563 => go 40004 Hello World! This is a test.
5564 ## Starting application at 0x00040004 ...
5575 Hit any key to exit ...
5577 ## Application terminated, rc = 0x0
5579 Another example, which demonstrates how to register a CPM interrupt
5580 handler with the U-Boot code, can be found in 'examples/timer.c'.
5581 Here, a CPM timer is set up to generate an interrupt every second.
5582 The interrupt service routine is trivial, just printing a '.'
5583 character, but this is just a demo program. The application can be
5584 controlled by the following keys:
5586 ? - print current values og the CPM Timer registers
5587 b - enable interrupts and start timer
5588 e - stop timer and disable interrupts
5589 q - quit application
5592 ## Ready for S-Record download ...
5593 ~>examples/timer.srec
5594 1 2 3 4 5 6 7 8 9 10 11 ...
5595 [file transfer complete]
5597 ## Start Addr = 0x00040004
5600 ## Starting application at 0x00040004 ...
5603 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5606 [q, b, e, ?] Set interval 1000000 us
5609 [q, b, e, ?] ........
5610 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5613 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5616 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5619 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5621 [q, b, e, ?] ...Stopping timer
5623 [q, b, e, ?] ## Application terminated, rc = 0x0
5629 Over time, many people have reported problems when trying to use the
5630 "minicom" terminal emulation program for serial download. I (wd)
5631 consider minicom to be broken, and recommend not to use it. Under
5632 Unix, I recommend to use C-Kermit for general purpose use (and
5633 especially for kermit binary protocol download ("loadb" command), and
5634 use "cu" for S-Record download ("loads" command). See
5635 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5636 for help with kermit.
5639 Nevertheless, if you absolutely want to use it try adding this
5640 configuration to your "File transfer protocols" section:
5642 Name Program Name U/D FullScr IO-Red. Multi
5643 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5644 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5650 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5651 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5653 Building requires a cross environment; it is known to work on
5654 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5655 need gmake since the Makefiles are not compatible with BSD make).
5656 Note that the cross-powerpc package does not install include files;
5657 attempting to build U-Boot will fail because <machine/ansi.h> is
5658 missing. This file has to be installed and patched manually:
5660 # cd /usr/pkg/cross/powerpc-netbsd/include
5662 # ln -s powerpc machine
5663 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5664 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5666 Native builds *don't* work due to incompatibilities between native
5667 and U-Boot include files.
5669 Booting assumes that (the first part of) the image booted is a
5670 stage-2 loader which in turn loads and then invokes the kernel
5671 proper. Loader sources will eventually appear in the NetBSD source
5672 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5673 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5676 Implementation Internals:
5677 =========================
5679 The following is not intended to be a complete description of every
5680 implementation detail. However, it should help to understand the
5681 inner workings of U-Boot and make it easier to port it to custom
5685 Initial Stack, Global Data:
5686 ---------------------------
5688 The implementation of U-Boot is complicated by the fact that U-Boot
5689 starts running out of ROM (flash memory), usually without access to
5690 system RAM (because the memory controller is not initialized yet).
5691 This means that we don't have writable Data or BSS segments, and BSS
5692 is not initialized as zero. To be able to get a C environment working
5693 at all, we have to allocate at least a minimal stack. Implementation
5694 options for this are defined and restricted by the CPU used: Some CPU
5695 models provide on-chip memory (like the IMMR area on MPC8xx and
5696 MPC826x processors), on others (parts of) the data cache can be
5697 locked as (mis-) used as memory, etc.
5699 Chris Hallinan posted a good summary of these issues to the
5700 U-Boot mailing list:
5702 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5703 From: "Chris Hallinan" <clh@net1plus.com>
5704 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5707 Correct me if I'm wrong, folks, but the way I understand it
5708 is this: Using DCACHE as initial RAM for Stack, etc, does not
5709 require any physical RAM backing up the cache. The cleverness
5710 is that the cache is being used as a temporary supply of
5711 necessary storage before the SDRAM controller is setup. It's
5712 beyond the scope of this list to explain the details, but you
5713 can see how this works by studying the cache architecture and
5714 operation in the architecture and processor-specific manuals.
5716 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5717 is another option for the system designer to use as an
5718 initial stack/RAM area prior to SDRAM being available. Either
5719 option should work for you. Using CS 4 should be fine if your
5720 board designers haven't used it for something that would
5721 cause you grief during the initial boot! It is frequently not
5724 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5725 with your processor/board/system design. The default value
5726 you will find in any recent u-boot distribution in
5727 walnut.h should work for you. I'd set it to a value larger
5728 than your SDRAM module. If you have a 64MB SDRAM module, set
5729 it above 400_0000. Just make sure your board has no resources
5730 that are supposed to respond to that address! That code in
5731 start.S has been around a while and should work as is when
5732 you get the config right.
5737 It is essential to remember this, since it has some impact on the C
5738 code for the initialization procedures:
5740 * Initialized global data (data segment) is read-only. Do not attempt
5743 * Do not use any uninitialized global data (or implicitly initialized
5744 as zero data - BSS segment) at all - this is undefined, initiali-
5745 zation is performed later (when relocating to RAM).
5747 * Stack space is very limited. Avoid big data buffers or things like
5750 Having only the stack as writable memory limits means we cannot use
5751 normal global data to share information between the code. But it
5752 turned out that the implementation of U-Boot can be greatly
5753 simplified by making a global data structure (gd_t) available to all
5754 functions. We could pass a pointer to this data as argument to _all_
5755 functions, but this would bloat the code. Instead we use a feature of
5756 the GCC compiler (Global Register Variables) to share the data: we
5757 place a pointer (gd) to the global data into a register which we
5758 reserve for this purpose.
5760 When choosing a register for such a purpose we are restricted by the
5761 relevant (E)ABI specifications for the current architecture, and by
5762 GCC's implementation.
5764 For PowerPC, the following registers have specific use:
5766 R2: reserved for system use
5767 R3-R4: parameter passing and return values
5768 R5-R10: parameter passing
5769 R13: small data area pointer
5773 (U-Boot also uses R12 as internal GOT pointer. r12
5774 is a volatile register so r12 needs to be reset when
5775 going back and forth between asm and C)
5777 ==> U-Boot will use R2 to hold a pointer to the global data
5779 Note: on PPC, we could use a static initializer (since the
5780 address of the global data structure is known at compile time),
5781 but it turned out that reserving a register results in somewhat
5782 smaller code - although the code savings are not that big (on
5783 average for all boards 752 bytes for the whole U-Boot image,
5784 624 text + 127 data).
5786 On ARM, the following registers are used:
5788 R0: function argument word/integer result
5789 R1-R3: function argument word
5790 R9: platform specific
5791 R10: stack limit (used only if stack checking is enabled)
5792 R11: argument (frame) pointer
5793 R12: temporary workspace
5796 R15: program counter
5798 ==> U-Boot will use R9 to hold a pointer to the global data
5800 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5802 On Nios II, the ABI is documented here:
5803 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5805 ==> U-Boot will use gp to hold a pointer to the global data
5807 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5808 to access small data sections, so gp is free.
5810 On NDS32, the following registers are used:
5812 R0-R1: argument/return
5814 R15: temporary register for assembler
5815 R16: trampoline register
5816 R28: frame pointer (FP)
5817 R29: global pointer (GP)
5818 R30: link register (LP)
5819 R31: stack pointer (SP)
5820 PC: program counter (PC)
5822 ==> U-Boot will use R10 to hold a pointer to the global data
5824 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5825 or current versions of GCC may "optimize" the code too much.
5830 U-Boot runs in system state and uses physical addresses, i.e. the
5831 MMU is not used either for address mapping nor for memory protection.
5833 The available memory is mapped to fixed addresses using the memory
5834 controller. In this process, a contiguous block is formed for each
5835 memory type (Flash, SDRAM, SRAM), even when it consists of several
5836 physical memory banks.
5838 U-Boot is installed in the first 128 kB of the first Flash bank (on
5839 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5840 booting and sizing and initializing DRAM, the code relocates itself
5841 to the upper end of DRAM. Immediately below the U-Boot code some
5842 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5843 configuration setting]. Below that, a structure with global Board
5844 Info data is placed, followed by the stack (growing downward).
5846 Additionally, some exception handler code is copied to the low 8 kB
5847 of DRAM (0x00000000 ... 0x00001FFF).
5849 So a typical memory configuration with 16 MB of DRAM could look like
5852 0x0000 0000 Exception Vector code
5855 0x0000 2000 Free for Application Use
5861 0x00FB FF20 Monitor Stack (Growing downward)
5862 0x00FB FFAC Board Info Data and permanent copy of global data
5863 0x00FC 0000 Malloc Arena
5866 0x00FE 0000 RAM Copy of Monitor Code
5867 ... eventually: LCD or video framebuffer
5868 ... eventually: pRAM (Protected RAM - unchanged by reset)
5869 0x00FF FFFF [End of RAM]
5872 System Initialization:
5873 ----------------------
5875 In the reset configuration, U-Boot starts at the reset entry point
5876 (on most PowerPC systems at address 0x00000100). Because of the reset
5877 configuration for CS0# this is a mirror of the on board Flash memory.
5878 To be able to re-map memory U-Boot then jumps to its link address.
5879 To be able to implement the initialization code in C, a (small!)
5880 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5881 which provide such a feature like MPC8xx or MPC8260), or in a locked
5882 part of the data cache. After that, U-Boot initializes the CPU core,
5883 the caches and the SIU.
5885 Next, all (potentially) available memory banks are mapped using a
5886 preliminary mapping. For example, we put them on 512 MB boundaries
5887 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5888 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5889 programmed for SDRAM access. Using the temporary configuration, a
5890 simple memory test is run that determines the size of the SDRAM
5893 When there is more than one SDRAM bank, and the banks are of
5894 different size, the largest is mapped first. For equal size, the first
5895 bank (CS2#) is mapped first. The first mapping is always for address
5896 0x00000000, with any additional banks following immediately to create
5897 contiguous memory starting from 0.
5899 Then, the monitor installs itself at the upper end of the SDRAM area
5900 and allocates memory for use by malloc() and for the global Board
5901 Info data; also, the exception vector code is copied to the low RAM
5902 pages, and the final stack is set up.
5904 Only after this relocation will you have a "normal" C environment;
5905 until that you are restricted in several ways, mostly because you are
5906 running from ROM, and because the code will have to be relocated to a
5910 U-Boot Porting Guide:
5911 ----------------------
5913 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5917 int main(int argc, char *argv[])
5919 sighandler_t no_more_time;
5921 signal(SIGALRM, no_more_time);
5922 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5924 if (available_money > available_manpower) {
5925 Pay consultant to port U-Boot;
5929 Download latest U-Boot source;
5931 Subscribe to u-boot mailing list;
5934 email("Hi, I am new to U-Boot, how do I get started?");
5937 Read the README file in the top level directory;
5938 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5939 Read applicable doc/*.README;
5940 Read the source, Luke;
5941 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5944 if (available_money > toLocalCurrency ($2500))
5947 Add a lot of aggravation and time;
5949 if (a similar board exists) { /* hopefully... */
5950 cp -a board/<similar> board/<myboard>
5951 cp include/configs/<similar>.h include/configs/<myboard>.h
5953 Create your own board support subdirectory;
5954 Create your own board include/configs/<myboard>.h file;
5956 Edit new board/<myboard> files
5957 Edit new include/configs/<myboard>.h
5962 Add / modify source code;
5966 email("Hi, I am having problems...");
5968 Send patch file to the U-Boot email list;
5969 if (reasonable critiques)
5970 Incorporate improvements from email list code review;
5972 Defend code as written;
5978 void no_more_time (int sig)
5987 All contributions to U-Boot should conform to the Linux kernel
5988 coding style; see the file "Documentation/CodingStyle" and the script
5989 "scripts/Lindent" in your Linux kernel source directory.
5991 Source files originating from a different project (for example the
5992 MTD subsystem) are generally exempt from these guidelines and are not
5993 reformatted to ease subsequent migration to newer versions of those
5996 Please note that U-Boot is implemented in C (and to some small parts in
5997 Assembler); no C++ is used, so please do not use C++ style comments (//)
6000 Please also stick to the following formatting rules:
6001 - remove any trailing white space
6002 - use TAB characters for indentation and vertical alignment, not spaces
6003 - make sure NOT to use DOS '\r\n' line feeds
6004 - do not add more than 2 consecutive empty lines to source files
6005 - do not add trailing empty lines to source files
6007 Submissions which do not conform to the standards may be returned
6008 with a request to reformat the changes.
6014 Since the number of patches for U-Boot is growing, we need to
6015 establish some rules. Submissions which do not conform to these rules
6016 may be rejected, even when they contain important and valuable stuff.
6018 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6020 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6021 see http://lists.denx.de/mailman/listinfo/u-boot
6023 When you send a patch, please include the following information with
6026 * For bug fixes: a description of the bug and how your patch fixes
6027 this bug. Please try to include a way of demonstrating that the
6028 patch actually fixes something.
6030 * For new features: a description of the feature and your
6033 * A CHANGELOG entry as plaintext (separate from the patch)
6035 * For major contributions, add a MAINTAINERS file with your
6036 information and associated file and directory references.
6038 * When you add support for a new board, don't forget to add a
6039 maintainer e-mail address to the boards.cfg file, too.
6041 * If your patch adds new configuration options, don't forget to
6042 document these in the README file.
6044 * The patch itself. If you are using git (which is *strongly*
6045 recommended) you can easily generate the patch using the
6046 "git format-patch". If you then use "git send-email" to send it to
6047 the U-Boot mailing list, you will avoid most of the common problems
6048 with some other mail clients.
6050 If you cannot use git, use "diff -purN OLD NEW". If your version of
6051 diff does not support these options, then get the latest version of
6054 The current directory when running this command shall be the parent
6055 directory of the U-Boot source tree (i. e. please make sure that
6056 your patch includes sufficient directory information for the
6059 We prefer patches as plain text. MIME attachments are discouraged,
6060 and compressed attachments must not be used.
6062 * If one logical set of modifications affects or creates several
6063 files, all these changes shall be submitted in a SINGLE patch file.
6065 * Changesets that contain different, unrelated modifications shall be
6066 submitted as SEPARATE patches, one patch per changeset.
6071 * Before sending the patch, run the buildman script on your patched
6072 source tree and make sure that no errors or warnings are reported
6073 for any of the boards.
6075 * Keep your modifications to the necessary minimum: A patch
6076 containing several unrelated changes or arbitrary reformats will be
6077 returned with a request to re-formatting / split it.
6079 * If you modify existing code, make sure that your new code does not
6080 add to the memory footprint of the code ;-) Small is beautiful!
6081 When adding new features, these should compile conditionally only
6082 (using #ifdef), and the resulting code with the new feature
6083 disabled must not need more memory than the old code without your
6086 * Remember that there is a size limit of 100 kB per message on the
6087 u-boot mailing list. Bigger patches will be moderated. If they are
6088 reasonable and not too big, they will be acknowledged. But patches
6089 bigger than the size limit should be avoided.