2 # (C) Copyright 2000 - 2013
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
186 /mpc5xx Files specific to Freescale MPC5xx CPUs
187 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
188 /mpc8xx Files specific to Freescale MPC8xx CPUs
189 /mpc824x Files specific to Freescale MPC824x CPUs
190 /mpc8260 Files specific to Freescale MPC8260 CPUs
191 /mpc85xx Files specific to Freescale MPC85xx CPUs
192 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
193 /lib Architecture specific library files
194 /sh Files generic to SH architecture
195 /cpu CPU specific files
196 /sh2 Files specific to sh2 CPUs
197 /sh3 Files specific to sh3 CPUs
198 /sh4 Files specific to sh4 CPUs
199 /lib Architecture specific library files
200 /sparc Files generic to SPARC architecture
201 /cpu CPU specific files
202 /leon2 Files specific to Gaisler LEON2 SPARC CPU
203 /leon3 Files specific to Gaisler LEON3 SPARC CPU
204 /lib Architecture specific library files
205 /x86 Files generic to x86 architecture
206 /cpu CPU specific files
207 /lib Architecture specific library files
208 /api Machine/arch independent API for external apps
209 /board Board dependent files
210 /common Misc architecture independent functions
211 /disk Code for disk drive partition handling
212 /doc Documentation (don't expect too much)
213 /drivers Commonly used device drivers
214 /dts Contains Makefile for building internal U-Boot fdt.
215 /examples Example code for standalone applications, etc.
216 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
217 /include Header Files
218 /lib Files generic to all architectures
219 /libfdt Library files to support flattened device trees
220 /lzma Library files to support LZMA decompression
221 /lzo Library files to support LZO decompression
223 /post Power On Self Test
224 /spl Secondary Program Loader framework
225 /tools Tools to build S-Record or U-Boot images, etc.
227 Software Configuration:
228 =======================
230 Configuration is usually done using C preprocessor defines; the
231 rationale behind that is to avoid dead code whenever possible.
233 There are two classes of configuration variables:
235 * Configuration _OPTIONS_:
236 These are selectable by the user and have names beginning with
239 * Configuration _SETTINGS_:
240 These depend on the hardware etc. and should not be meddled with if
241 you don't know what you're doing; they have names beginning with
244 Later we will add a configuration tool - probably similar to or even
245 identical to what's used for the Linux kernel. Right now, we have to
246 do the configuration by hand, which means creating some symbolic
247 links and editing some configuration files. We use the TQM8xxL boards
251 Selection of Processor Architecture and Board Type:
252 ---------------------------------------------------
254 For all supported boards there are ready-to-use default
255 configurations available; just type "make <board_name>_defconfig".
257 Example: For a TQM823L module type:
260 make TQM823L_defconfig
262 For the Cogent platform, you need to specify the CPU type as well;
263 e.g. "make cogent_mpc8xx_defconfig". And also configure the cogent
264 directory according to the instructions in cogent/README.
270 U-Boot can be built natively to run on a Linux host using the 'sandbox'
271 board. This allows feature development which is not board- or architecture-
272 specific to be undertaken on a native platform. The sandbox is also used to
273 run some of U-Boot's tests.
275 See board/sandbox/README.sandbox for more details.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Marvell Family Member
325 CONFIG_SYS_MVFS - define it if you want to enable
326 multiple fs option at one time
327 for marvell soc family
329 - MPC824X Family Member (if CONFIG_MPC824X is defined)
330 Define exactly one of
331 CONFIG_MPC8240, CONFIG_MPC8245
333 - 8xx CPU Options: (if using an MPC8xx CPU)
334 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
335 get_gclk_freq() cannot work
336 e.g. if there is no 32KHz
337 reference PIT/RTC clock
338 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
341 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
342 CONFIG_SYS_8xx_CPUCLK_MIN
343 CONFIG_SYS_8xx_CPUCLK_MAX
344 CONFIG_8xx_CPUCLK_DEFAULT
345 See doc/README.MPC866
347 CONFIG_SYS_MEASURE_CPUCLK
349 Define this to measure the actual CPU clock instead
350 of relying on the correctness of the configured
351 values. Mostly useful for board bringup to make sure
352 the PLL is locked at the intended frequency. Note
353 that this requires a (stable) reference clock (32 kHz
354 RTC clock or CONFIG_SYS_8XX_XIN)
356 CONFIG_SYS_DELAYED_ICACHE
358 Define this option if you want to enable the
359 ICache only when Code runs from RAM.
364 Specifies that the core is a 64-bit PowerPC implementation (implements
365 the "64" category of the Power ISA). This is necessary for ePAPR
366 compliance, among other possible reasons.
368 CONFIG_SYS_FSL_TBCLK_DIV
370 Defines the core time base clock divider ratio compared to the
371 system clock. On most PQ3 devices this is 8, on newer QorIQ
372 devices it can be 16 or 32. The ratio varies from SoC to Soc.
374 CONFIG_SYS_FSL_PCIE_COMPAT
376 Defines the string to utilize when trying to match PCIe device
377 tree nodes for the given platform.
379 CONFIG_SYS_PPC_E500_DEBUG_TLB
381 Enables a temporary TLB entry to be used during boot to work
382 around limitations in e500v1 and e500v2 external debugger
383 support. This reduces the portions of the boot code where
384 breakpoints and single stepping do not work. The value of this
385 symbol should be set to the TLB1 entry to be used for this
388 CONFIG_SYS_FSL_ERRATUM_A004510
390 Enables a workaround for erratum A004510. If set,
391 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
392 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
394 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
395 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
397 Defines one or two SoC revisions (low 8 bits of SVR)
398 for which the A004510 workaround should be applied.
400 The rest of SVR is either not relevant to the decision
401 of whether the erratum is present (e.g. p2040 versus
402 p2041) or is implied by the build target, which controls
403 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
405 See Freescale App Note 4493 for more information about
408 CONFIG_A003399_NOR_WORKAROUND
409 Enables a workaround for IFC erratum A003399. It is only
410 requred during NOR boot.
412 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
414 This is the value to write into CCSR offset 0x18600
415 according to the A004510 workaround.
417 CONFIG_SYS_FSL_DSP_DDR_ADDR
418 This value denotes start offset of DDR memory which is
419 connected exclusively to the DSP cores.
421 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
422 This value denotes start offset of M2 memory
423 which is directly connected to the DSP core.
425 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
426 This value denotes start offset of M3 memory which is directly
427 connected to the DSP core.
429 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
430 This value denotes start offset of DSP CCSR space.
432 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
433 Single Source Clock is clocking mode present in some of FSL SoC's.
434 In this mode, a single differential clock is used to supply
435 clocks to the sysclock, ddrclock and usbclock.
437 CONFIG_SYS_CPC_REINIT_F
438 This CONFIG is defined when the CPC is configured as SRAM at the
439 time of U-boot entry and is required to be re-initialized.
442 Inidcates this SoC supports deep sleep feature. If deep sleep is
443 supported, core will start to execute uboot when wakes up.
445 - Generic CPU options:
446 CONFIG_SYS_GENERIC_GLOBAL_DATA
447 Defines global data is initialized in generic board board_init_f().
448 If this macro is defined, global data is created and cleared in
449 generic board board_init_f(). Without this macro, architecture/board
450 should initialize global data before calling board_init_f().
452 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
454 Defines the endianess of the CPU. Implementation of those
455 values is arch specific.
458 Freescale DDR driver in use. This type of DDR controller is
459 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
462 CONFIG_SYS_FSL_DDR_ADDR
463 Freescale DDR memory-mapped register base.
465 CONFIG_SYS_FSL_DDR_EMU
466 Specify emulator support for DDR. Some DDR features such as
467 deskew training are not available.
469 CONFIG_SYS_FSL_DDRC_GEN1
470 Freescale DDR1 controller.
472 CONFIG_SYS_FSL_DDRC_GEN2
473 Freescale DDR2 controller.
475 CONFIG_SYS_FSL_DDRC_GEN3
476 Freescale DDR3 controller.
478 CONFIG_SYS_FSL_DDRC_GEN4
479 Freescale DDR4 controller.
481 CONFIG_SYS_FSL_DDRC_ARM_GEN3
482 Freescale DDR3 controller for ARM-based SoCs.
485 Board config to use DDR1. It can be enabled for SoCs with
486 Freescale DDR1 or DDR2 controllers, depending on the board
490 Board config to use DDR2. It can be eanbeld for SoCs with
491 Freescale DDR2 or DDR3 controllers, depending on the board
495 Board config to use DDR3. It can be enabled for SoCs with
496 Freescale DDR3 or DDR3L controllers.
499 Board config to use DDR3L. It can be enabled for SoCs with
503 Board config to use DDR4. It can be enabled for SoCs with
506 CONFIG_SYS_FSL_IFC_BE
507 Defines the IFC controller register space as Big Endian
509 CONFIG_SYS_FSL_IFC_LE
510 Defines the IFC controller register space as Little Endian
512 CONFIG_SYS_FSL_PBL_PBI
513 It enables addition of RCW (Power on reset configuration) in built image.
514 Please refer doc/README.pblimage for more details
516 CONFIG_SYS_FSL_PBL_RCW
517 It adds PBI(pre-boot instructions) commands in u-boot build image.
518 PBI commands can be used to configure SoC before it starts the execution.
519 Please refer doc/README.pblimage for more details
522 It adds a target to create boot binary having SPL binary in PBI format
523 concatenated with u-boot binary.
525 CONFIG_SYS_FSL_DDR_BE
526 Defines the DDR controller register space as Big Endian
528 CONFIG_SYS_FSL_DDR_LE
529 Defines the DDR controller register space as Little Endian
531 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
532 Physical address from the view of DDR controllers. It is the
533 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
534 it could be different for ARM SoCs.
536 CONFIG_SYS_FSL_DDR_INTLV_256B
537 DDR controller interleaving on 256-byte. This is a special
538 interleaving mode, handled by Dickens for Freescale layerscape
541 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
542 Number of controllers used as main memory.
544 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
545 Number of controllers used for other than main memory.
547 CONFIG_SYS_FSL_SEC_BE
548 Defines the SEC controller register space as Big Endian
550 CONFIG_SYS_FSL_SEC_LE
551 Defines the SEC controller register space as Little Endian
553 - Intel Monahans options:
554 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
556 Defines the Monahans run mode to oscillator
557 ratio. Valid values are 8, 16, 24, 31. The core
558 frequency is this value multiplied by 13 MHz.
560 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
562 Defines the Monahans turbo mode to oscillator
563 ratio. Valid values are 1 (default if undefined) and
564 2. The core frequency as calculated above is multiplied
568 CONFIG_SYS_INIT_SP_OFFSET
570 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
571 pointer. This is needed for the temporary stack before
574 CONFIG_SYS_MIPS_CACHE_MODE
576 Cache operation mode for the MIPS CPU.
577 See also arch/mips/include/asm/mipsregs.h.
579 CONF_CM_CACHABLE_NO_WA
582 CONF_CM_CACHABLE_NONCOHERENT
586 CONF_CM_CACHABLE_ACCELERATED
588 CONFIG_SYS_XWAY_EBU_BOOTCFG
590 Special option for Lantiq XWAY SoCs for booting from NOR flash.
591 See also arch/mips/cpu/mips32/start.S.
593 CONFIG_XWAY_SWAP_BYTES
595 Enable compilation of tools/xway-swap-bytes needed for Lantiq
596 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
597 be swapped if a flash programmer is used.
600 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
602 Select high exception vectors of the ARM core, e.g., do not
603 clear the V bit of the c1 register of CP15.
605 CONFIG_SYS_THUMB_BUILD
607 Use this flag to build U-Boot using the Thumb instruction
608 set for ARM architectures. Thumb instruction set provides
609 better code density. For ARM architectures that support
610 Thumb2 this flag will result in Thumb2 code generated by
613 CONFIG_ARM_ERRATA_716044
614 CONFIG_ARM_ERRATA_742230
615 CONFIG_ARM_ERRATA_743622
616 CONFIG_ARM_ERRATA_751472
617 CONFIG_ARM_ERRATA_794072
618 CONFIG_ARM_ERRATA_761320
620 If set, the workarounds for these ARM errata are applied early
621 during U-Boot startup. Note that these options force the
622 workarounds to be applied; no CPU-type/version detection
623 exists, unlike the similar options in the Linux kernel. Do not
624 set these options unless they apply!
629 The frequency of the timer returned by get_timer().
630 get_timer() must operate in milliseconds and this CONFIG
631 option must be set to 1000.
633 - Linux Kernel Interface:
636 U-Boot stores all clock information in Hz
637 internally. For binary compatibility with older Linux
638 kernels (which expect the clocks passed in the
639 bd_info data to be in MHz) the environment variable
640 "clocks_in_mhz" can be defined so that U-Boot
641 converts clock data to MHZ before passing it to the
643 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
644 "clocks_in_mhz=1" is automatically included in the
647 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
649 When transferring memsize parameter to linux, some versions
650 expect it to be in bytes, others in MB.
651 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
655 New kernel versions are expecting firmware settings to be
656 passed using flattened device trees (based on open firmware
660 * New libfdt-based support
661 * Adds the "fdt" command
662 * The bootm command automatically updates the fdt
664 OF_CPU - The proper name of the cpus node (only required for
665 MPC512X and MPC5xxx based boards).
666 OF_SOC - The proper name of the soc node (only required for
667 MPC512X and MPC5xxx based boards).
668 OF_TBCLK - The timebase frequency.
669 OF_STDOUT_PATH - The path to the console device
671 boards with QUICC Engines require OF_QE to set UCC MAC
674 CONFIG_OF_BOARD_SETUP
676 Board code has addition modification that it wants to make
677 to the flat device tree before handing it off to the kernel
681 This define fills in the correct boot CPU in the boot
682 param header, the default value is zero if undefined.
686 U-Boot can detect if an IDE device is present or not.
687 If not, and this new config option is activated, U-Boot
688 removes the ATA node from the DTS before booting Linux,
689 so the Linux IDE driver does not probe the device and
690 crash. This is needed for buggy hardware (uc101) where
691 no pull down resistor is connected to the signal IDE5V_DD7.
693 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
695 This setting is mandatory for all boards that have only one
696 machine type and must be used to specify the machine type
697 number as it appears in the ARM machine registry
698 (see http://www.arm.linux.org.uk/developer/machines/).
699 Only boards that have multiple machine types supported
700 in a single configuration file and the machine type is
701 runtime discoverable, do not have to use this setting.
703 - vxWorks boot parameters:
705 bootvx constructs a valid bootline using the following
706 environments variables: bootfile, ipaddr, serverip, hostname.
707 It loads the vxWorks image pointed bootfile.
709 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
710 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
711 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
712 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
714 CONFIG_SYS_VXWORKS_ADD_PARAMS
716 Add it at the end of the bootline. E.g "u=username pw=secret"
718 Note: If a "bootargs" environment is defined, it will overwride
719 the defaults discussed just above.
721 - Cache Configuration:
722 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
723 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
724 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
726 - Cache Configuration for ARM:
727 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
729 CONFIG_SYS_PL310_BASE - Physical base address of PL310
730 controller register space
735 Define this if you want support for Amba PrimeCell PL010 UARTs.
739 Define this if you want support for Amba PrimeCell PL011 UARTs.
743 If you have Amba PrimeCell PL011 UARTs, set this variable to
744 the clock speed of the UARTs.
748 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
749 define this to a list of base addresses for each (supported)
750 port. See e.g. include/configs/versatile.h
752 CONFIG_PL011_SERIAL_RLCR
754 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
755 have separate receive and transmit line control registers. Set
756 this variable to initialize the extra register.
758 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
760 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
761 boot loader that has already initialized the UART. Define this
762 variable to flush the UART at init time.
764 CONFIG_SERIAL_HW_FLOW_CONTROL
766 Define this variable to enable hw flow control in serial driver.
767 Current user of this option is drivers/serial/nsl16550.c driver
770 Depending on board, define exactly one serial port
771 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
772 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
773 console by defining CONFIG_8xx_CONS_NONE
775 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
776 port routines must be defined elsewhere
777 (i.e. serial_init(), serial_getc(), ...)
780 Enables console device for a color framebuffer. Needs following
781 defines (cf. smiLynxEM, i8042)
782 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
784 VIDEO_HW_RECTFILL graphic chip supports
787 VIDEO_HW_BITBLT graphic chip supports
788 bit-blit (cf. smiLynxEM)
789 VIDEO_VISIBLE_COLS visible pixel columns
791 VIDEO_VISIBLE_ROWS visible pixel rows
792 VIDEO_PIXEL_SIZE bytes per pixel
793 VIDEO_DATA_FORMAT graphic data format
794 (0-5, cf. cfb_console.c)
795 VIDEO_FB_ADRS framebuffer address
796 VIDEO_KBD_INIT_FCT keyboard int fct
797 (i.e. i8042_kbd_init())
798 VIDEO_TSTC_FCT test char fct
800 VIDEO_GETC_FCT get char fct
802 CONFIG_CONSOLE_CURSOR cursor drawing on/off
803 (requires blink timer
805 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
806 CONFIG_CONSOLE_TIME display time/date info in
808 (requires CONFIG_CMD_DATE)
809 CONFIG_VIDEO_LOGO display Linux logo in
811 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
812 linux_logo.h for logo.
813 Requires CONFIG_VIDEO_LOGO
814 CONFIG_CONSOLE_EXTRA_INFO
815 additional board info beside
818 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
819 a limited number of ANSI escape sequences (cursor control,
820 erase functions and limited graphics rendition control).
822 When CONFIG_CFB_CONSOLE is defined, video console is
823 default i/o. Serial console can be forced with
824 environment 'console=serial'.
826 When CONFIG_SILENT_CONSOLE is defined, all console
827 messages (by U-Boot and Linux!) can be silenced with
828 the "silent" environment variable. See
829 doc/README.silent for more information.
831 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
833 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
837 CONFIG_BAUDRATE - in bps
838 Select one of the baudrates listed in
839 CONFIG_SYS_BAUDRATE_TABLE, see below.
840 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
842 - Console Rx buffer length
843 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
844 the maximum receive buffer length for the SMC.
845 This option is actual only for 82xx and 8xx possible.
846 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
847 must be defined, to setup the maximum idle timeout for
850 - Pre-Console Buffer:
851 Prior to the console being initialised (i.e. serial UART
852 initialised etc) all console output is silently discarded.
853 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
854 buffer any console messages prior to the console being
855 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
856 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
857 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
858 bytes are output before the console is initialised, the
859 earlier bytes are discarded.
861 'Sane' compilers will generate smaller code if
862 CONFIG_PRE_CON_BUF_SZ is a power of 2
864 - Safe printf() functions
865 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
866 the printf() functions. These are defined in
867 include/vsprintf.h and include snprintf(), vsnprintf() and
868 so on. Code size increase is approximately 300-500 bytes.
869 If this option is not given then these functions will
870 silently discard their buffer size argument - this means
871 you are not getting any overflow checking in this case.
873 - Boot Delay: CONFIG_BOOTDELAY - in seconds
874 Delay before automatically booting the default image;
875 set to -1 to disable autoboot.
876 set to -2 to autoboot with no delay and not check for abort
877 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
879 See doc/README.autoboot for these options that
880 work with CONFIG_BOOTDELAY. None are required.
881 CONFIG_BOOT_RETRY_TIME
882 CONFIG_BOOT_RETRY_MIN
883 CONFIG_AUTOBOOT_KEYED
884 CONFIG_AUTOBOOT_PROMPT
885 CONFIG_AUTOBOOT_DELAY_STR
886 CONFIG_AUTOBOOT_STOP_STR
887 CONFIG_AUTOBOOT_DELAY_STR2
888 CONFIG_AUTOBOOT_STOP_STR2
889 CONFIG_ZERO_BOOTDELAY_CHECK
890 CONFIG_RESET_TO_RETRY
894 Only needed when CONFIG_BOOTDELAY is enabled;
895 define a command string that is automatically executed
896 when no character is read on the console interface
897 within "Boot Delay" after reset.
900 This can be used to pass arguments to the bootm
901 command. The value of CONFIG_BOOTARGS goes into the
902 environment value "bootargs".
904 CONFIG_RAMBOOT and CONFIG_NFSBOOT
905 The value of these goes into the environment as
906 "ramboot" and "nfsboot" respectively, and can be used
907 as a convenience, when switching between booting from
911 CONFIG_BOOTCOUNT_LIMIT
912 Implements a mechanism for detecting a repeating reboot
914 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
917 If no softreset save registers are found on the hardware
918 "bootcount" is stored in the environment. To prevent a
919 saveenv on all reboots, the environment variable
920 "upgrade_available" is used. If "upgrade_available" is
921 0, "bootcount" is always 0, if "upgrade_available" is
922 1 "bootcount" is incremented in the environment.
923 So the Userspace Applikation must set the "upgrade_available"
924 and "bootcount" variable to 0, if a boot was successfully.
929 When this option is #defined, the existence of the
930 environment variable "preboot" will be checked
931 immediately before starting the CONFIG_BOOTDELAY
932 countdown and/or running the auto-boot command resp.
933 entering interactive mode.
935 This feature is especially useful when "preboot" is
936 automatically generated or modified. For an example
937 see the LWMON board specific code: here "preboot" is
938 modified when the user holds down a certain
939 combination of keys on the (special) keyboard when
942 - Serial Download Echo Mode:
944 If defined to 1, all characters received during a
945 serial download (using the "loads" command) are
946 echoed back. This might be needed by some terminal
947 emulations (like "cu"), but may as well just take
948 time on others. This setting #define's the initial
949 value of the "loads_echo" environment variable.
951 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
953 Select one of the baudrates listed in
954 CONFIG_SYS_BAUDRATE_TABLE, see below.
957 Monitor commands can be included or excluded
958 from the build by using the #include files
959 <config_cmd_all.h> and #undef'ing unwanted
960 commands, or using <config_cmd_default.h>
961 and augmenting with additional #define's
964 The default command configuration includes all commands
965 except those marked below with a "*".
967 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
968 CONFIG_CMD_ASKENV * ask for env variable
969 CONFIG_CMD_BDI bdinfo
970 CONFIG_CMD_BEDBUG * Include BedBug Debugger
971 CONFIG_CMD_BMP * BMP support
972 CONFIG_CMD_BSP * Board specific commands
973 CONFIG_CMD_BOOTD bootd
974 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
975 CONFIG_CMD_CACHE * icache, dcache
976 CONFIG_CMD_CLK * clock command support
977 CONFIG_CMD_CONSOLE coninfo
978 CONFIG_CMD_CRC32 * crc32
979 CONFIG_CMD_DATE * support for RTC, date/time...
980 CONFIG_CMD_DHCP * DHCP support
981 CONFIG_CMD_DIAG * Diagnostics
982 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
983 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
984 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
985 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
986 CONFIG_CMD_DTT * Digital Therm and Thermostat
987 CONFIG_CMD_ECHO echo arguments
988 CONFIG_CMD_EDITENV edit env variable
989 CONFIG_CMD_EEPROM * EEPROM read/write support
990 CONFIG_CMD_ELF * bootelf, bootvx
991 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
992 CONFIG_CMD_ENV_FLAGS * display details about env flags
993 CONFIG_CMD_ENV_EXISTS * check existence of env variable
994 CONFIG_CMD_EXPORTENV * export the environment
995 CONFIG_CMD_EXT2 * ext2 command support
996 CONFIG_CMD_EXT4 * ext4 command support
997 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
998 that work for multiple fs types
999 CONFIG_CMD_SAVEENV saveenv
1000 CONFIG_CMD_FDC * Floppy Disk Support
1001 CONFIG_CMD_FAT * FAT command support
1002 CONFIG_CMD_FLASH flinfo, erase, protect
1003 CONFIG_CMD_FPGA FPGA device initialization support
1004 CONFIG_CMD_FUSE * Device fuse support
1005 CONFIG_CMD_GETTIME * Get time since boot
1006 CONFIG_CMD_GO * the 'go' command (exec code)
1007 CONFIG_CMD_GREPENV * search environment
1008 CONFIG_CMD_HASH * calculate hash / digest
1009 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
1010 CONFIG_CMD_I2C * I2C serial bus support
1011 CONFIG_CMD_IDE * IDE harddisk support
1012 CONFIG_CMD_IMI iminfo
1013 CONFIG_CMD_IMLS List all images found in NOR flash
1014 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1015 CONFIG_CMD_IMMAP * IMMR dump support
1016 CONFIG_CMD_IOTRACE * I/O tracing for debugging
1017 CONFIG_CMD_IMPORTENV * import an environment
1018 CONFIG_CMD_INI * import data from an ini file into the env
1019 CONFIG_CMD_IRQ * irqinfo
1020 CONFIG_CMD_ITEST Integer/string test of 2 values
1021 CONFIG_CMD_JFFS2 * JFFS2 Support
1022 CONFIG_CMD_KGDB * kgdb
1023 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1024 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1026 CONFIG_CMD_LOADB loadb
1027 CONFIG_CMD_LOADS loads
1028 CONFIG_CMD_MD5SUM * print md5 message digest
1029 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1030 CONFIG_CMD_MEMINFO * Display detailed memory information
1031 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1033 CONFIG_CMD_MEMTEST * mtest
1034 CONFIG_CMD_MISC Misc functions like sleep etc
1035 CONFIG_CMD_MMC * MMC memory mapped support
1036 CONFIG_CMD_MII * MII utility commands
1037 CONFIG_CMD_MTDPARTS * MTD partition support
1038 CONFIG_CMD_NAND * NAND support
1039 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1040 CONFIG_CMD_NFS NFS support
1041 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1042 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1043 CONFIG_CMD_PCI * pciinfo
1044 CONFIG_CMD_PCMCIA * PCMCIA support
1045 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1047 CONFIG_CMD_PORTIO * Port I/O
1048 CONFIG_CMD_READ * Read raw data from partition
1049 CONFIG_CMD_REGINFO * Register dump
1050 CONFIG_CMD_RUN run command in env variable
1051 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1052 CONFIG_CMD_SAVES * save S record dump
1053 CONFIG_CMD_SCSI * SCSI Support
1054 CONFIG_CMD_SDRAM * print SDRAM configuration information
1055 (requires CONFIG_CMD_I2C)
1056 CONFIG_CMD_SETGETDCR Support for DCR Register access
1058 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1059 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1060 (requires CONFIG_CMD_MEMORY)
1061 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1062 CONFIG_CMD_SOURCE "source" command Support
1063 CONFIG_CMD_SPI * SPI serial bus support
1064 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1065 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1066 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1067 CONFIG_CMD_TIMER * access to the system tick timer
1068 CONFIG_CMD_USB * USB support
1069 CONFIG_CMD_CDP * Cisco Discover Protocol support
1070 CONFIG_CMD_MFSL * Microblaze FSL support
1071 CONFIG_CMD_XIMG Load part of Multi Image
1072 CONFIG_CMD_UUID * Generate random UUID or GUID string
1074 EXAMPLE: If you want all functions except of network
1075 support you can write:
1077 #include "config_cmd_all.h"
1078 #undef CONFIG_CMD_NET
1081 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1083 Note: Don't enable the "icache" and "dcache" commands
1084 (configuration option CONFIG_CMD_CACHE) unless you know
1085 what you (and your U-Boot users) are doing. Data
1086 cache cannot be enabled on systems like the 8xx or
1087 8260 (where accesses to the IMMR region must be
1088 uncached), and it cannot be disabled on all other
1089 systems where we (mis-) use the data cache to hold an
1090 initial stack and some data.
1093 XXX - this list needs to get updated!
1095 - Regular expression support:
1097 If this variable is defined, U-Boot is linked against
1098 the SLRE (Super Light Regular Expression) library,
1099 which adds regex support to some commands, as for
1100 example "env grep" and "setexpr".
1104 If this variable is defined, U-Boot will use a device tree
1105 to configure its devices, instead of relying on statically
1106 compiled #defines in the board file. This option is
1107 experimental and only available on a few boards. The device
1108 tree is available in the global data as gd->fdt_blob.
1110 U-Boot needs to get its device tree from somewhere. This can
1111 be done using one of the two options below:
1114 If this variable is defined, U-Boot will embed a device tree
1115 binary in its image. This device tree file should be in the
1116 board directory and called <soc>-<board>.dts. The binary file
1117 is then picked up in board_init_f() and made available through
1118 the global data structure as gd->blob.
1121 If this variable is defined, U-Boot will build a device tree
1122 binary. It will be called u-boot.dtb. Architecture-specific
1123 code will locate it at run-time. Generally this works by:
1125 cat u-boot.bin u-boot.dtb >image.bin
1127 and in fact, U-Boot does this for you, creating a file called
1128 u-boot-dtb.bin which is useful in the common case. You can
1129 still use the individual files if you need something more
1134 If this variable is defined, it enables watchdog
1135 support for the SoC. There must be support in the SoC
1136 specific code for a watchdog. For the 8xx and 8260
1137 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1138 register. When supported for a specific SoC is
1139 available, then no further board specific code should
1140 be needed to use it.
1143 When using a watchdog circuitry external to the used
1144 SoC, then define this variable and provide board
1145 specific code for the "hw_watchdog_reset" function.
1148 CONFIG_VERSION_VARIABLE
1149 If this variable is defined, an environment variable
1150 named "ver" is created by U-Boot showing the U-Boot
1151 version as printed by the "version" command.
1152 Any change to this variable will be reverted at the
1157 When CONFIG_CMD_DATE is selected, the type of the RTC
1158 has to be selected, too. Define exactly one of the
1161 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1162 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1163 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1164 CONFIG_RTC_MC146818 - use MC146818 RTC
1165 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1166 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1167 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1168 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1169 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1170 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1171 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1172 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1173 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1176 Note that if the RTC uses I2C, then the I2C interface
1177 must also be configured. See I2C Support, below.
1180 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1182 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1183 chip-ngpio pairs that tell the PCA953X driver the number of
1184 pins supported by a particular chip.
1186 Note that if the GPIO device uses I2C, then the I2C interface
1187 must also be configured. See I2C Support, below.
1190 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1191 accesses and can checksum them or write a list of them out
1192 to memory. See the 'iotrace' command for details. This is
1193 useful for testing device drivers since it can confirm that
1194 the driver behaves the same way before and after a code
1195 change. Currently this is supported on sandbox and arm. To
1196 add support for your architecture, add '#include <iotrace.h>'
1197 to the bottom of arch/<arch>/include/asm/io.h and test.
1199 Example output from the 'iotrace stats' command is below.
1200 Note that if the trace buffer is exhausted, the checksum will
1201 still continue to operate.
1204 Start: 10000000 (buffer start address)
1205 Size: 00010000 (buffer size)
1206 Offset: 00000120 (current buffer offset)
1207 Output: 10000120 (start + offset)
1208 Count: 00000018 (number of trace records)
1209 CRC32: 9526fb66 (CRC32 of all trace records)
1211 - Timestamp Support:
1213 When CONFIG_TIMESTAMP is selected, the timestamp
1214 (date and time) of an image is printed by image
1215 commands like bootm or iminfo. This option is
1216 automatically enabled when you select CONFIG_CMD_DATE .
1218 - Partition Labels (disklabels) Supported:
1219 Zero or more of the following:
1220 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1221 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1222 Intel architecture, USB sticks, etc.
1223 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1224 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1225 bootloader. Note 2TB partition limit; see
1227 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1229 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1230 CONFIG_CMD_SCSI) you must configure support for at
1231 least one non-MTD partition type as well.
1234 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1235 board configurations files but used nowhere!
1237 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1238 be performed by calling the function
1239 ide_set_reset(int reset)
1240 which has to be defined in a board specific file
1245 Set this to enable ATAPI support.
1250 Set this to enable support for disks larger than 137GB
1251 Also look at CONFIG_SYS_64BIT_LBA.
1252 Whithout these , LBA48 support uses 32bit variables and will 'only'
1253 support disks up to 2.1TB.
1255 CONFIG_SYS_64BIT_LBA:
1256 When enabled, makes the IDE subsystem use 64bit sector addresses.
1260 At the moment only there is only support for the
1261 SYM53C8XX SCSI controller; define
1262 CONFIG_SCSI_SYM53C8XX to enable it.
1264 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1265 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1266 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1267 maximum numbers of LUNs, SCSI ID's and target
1269 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1271 The environment variable 'scsidevs' is set to the number of
1272 SCSI devices found during the last scan.
1274 - NETWORK Support (PCI):
1276 Support for Intel 8254x/8257x gigabit chips.
1279 Utility code for direct access to the SPI bus on Intel 8257x.
1280 This does not do anything useful unless you set at least one
1281 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1283 CONFIG_E1000_SPI_GENERIC
1284 Allow generic access to the SPI bus on the Intel 8257x, for
1285 example with the "sspi" command.
1288 Management command for E1000 devices. When used on devices
1289 with SPI support you can reprogram the EEPROM from U-Boot.
1291 CONFIG_E1000_FALLBACK_MAC
1292 default MAC for empty EEPROM after production.
1295 Support for Intel 82557/82559/82559ER chips.
1296 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1297 write routine for first time initialisation.
1300 Support for Digital 2114x chips.
1301 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1302 modem chip initialisation (KS8761/QS6611).
1305 Support for National dp83815 chips.
1308 Support for National dp8382[01] gigabit chips.
1310 - NETWORK Support (other):
1312 CONFIG_DRIVER_AT91EMAC
1313 Support for AT91RM9200 EMAC.
1316 Define this to use reduced MII inteface
1318 CONFIG_DRIVER_AT91EMAC_QUIET
1319 If this defined, the driver is quiet.
1320 The driver doen't show link status messages.
1322 CONFIG_CALXEDA_XGMAC
1323 Support for the Calxeda XGMAC device
1326 Support for SMSC's LAN91C96 chips.
1328 CONFIG_LAN91C96_BASE
1329 Define this to hold the physical address
1330 of the LAN91C96's I/O space
1332 CONFIG_LAN91C96_USE_32_BIT
1333 Define this to enable 32 bit addressing
1336 Support for SMSC's LAN91C111 chip
1338 CONFIG_SMC91111_BASE
1339 Define this to hold the physical address
1340 of the device (I/O space)
1342 CONFIG_SMC_USE_32_BIT
1343 Define this if data bus is 32 bits
1345 CONFIG_SMC_USE_IOFUNCS
1346 Define this to use i/o functions instead of macros
1347 (some hardware wont work with macros)
1349 CONFIG_DRIVER_TI_EMAC
1350 Support for davinci emac
1352 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1353 Define this if you have more then 3 PHYs.
1356 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1358 CONFIG_FTGMAC100_EGIGA
1359 Define this to use GE link update with gigabit PHY.
1360 Define this if FTGMAC100 is connected to gigabit PHY.
1361 If your system has 10/100 PHY only, it might not occur
1362 wrong behavior. Because PHY usually return timeout or
1363 useless data when polling gigabit status and gigabit
1364 control registers. This behavior won't affect the
1365 correctnessof 10/100 link speed update.
1368 Support for SMSC's LAN911x and LAN921x chips
1371 Define this to hold the physical address
1372 of the device (I/O space)
1374 CONFIG_SMC911X_32_BIT
1375 Define this if data bus is 32 bits
1377 CONFIG_SMC911X_16_BIT
1378 Define this if data bus is 16 bits. If your processor
1379 automatically converts one 32 bit word to two 16 bit
1380 words you may also try CONFIG_SMC911X_32_BIT.
1383 Support for Renesas on-chip Ethernet controller
1385 CONFIG_SH_ETHER_USE_PORT
1386 Define the number of ports to be used
1388 CONFIG_SH_ETHER_PHY_ADDR
1389 Define the ETH PHY's address
1391 CONFIG_SH_ETHER_CACHE_WRITEBACK
1392 If this option is set, the driver enables cache flush.
1396 Support for PWM modul on the imx6.
1400 Support TPM devices.
1403 Support for i2c bus TPM devices. Only one device
1404 per system is supported at this time.
1406 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1407 Define the the i2c bus number for the TPM device
1409 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1410 Define the TPM's address on the i2c bus
1412 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1413 Define the burst count bytes upper limit
1415 CONFIG_TPM_ATMEL_TWI
1416 Support for Atmel TWI TPM device. Requires I2C support.
1419 Support for generic parallel port TPM devices. Only one device
1420 per system is supported at this time.
1422 CONFIG_TPM_TIS_BASE_ADDRESS
1423 Base address where the generic TPM device is mapped
1424 to. Contemporary x86 systems usually map it at
1428 Add tpm monitor functions.
1429 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1430 provides monitor access to authorized functions.
1433 Define this to enable the TPM support library which provides
1434 functional interfaces to some TPM commands.
1435 Requires support for a TPM device.
1437 CONFIG_TPM_AUTH_SESSIONS
1438 Define this to enable authorized functions in the TPM library.
1439 Requires CONFIG_TPM and CONFIG_SHA1.
1442 At the moment only the UHCI host controller is
1443 supported (PIP405, MIP405, MPC5200); define
1444 CONFIG_USB_UHCI to enable it.
1445 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1446 and define CONFIG_USB_STORAGE to enable the USB
1449 Supported are USB Keyboards and USB Floppy drives
1451 MPC5200 USB requires additional defines:
1453 for 528 MHz Clock: 0x0001bbbb
1457 for differential drivers: 0x00001000
1458 for single ended drivers: 0x00005000
1459 for differential drivers on PSC3: 0x00000100
1460 for single ended drivers on PSC3: 0x00004100
1461 CONFIG_SYS_USB_EVENT_POLL
1462 May be defined to allow interrupt polling
1463 instead of using asynchronous interrupts
1465 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1466 txfilltuning field in the EHCI controller on reset.
1469 Define the below if you wish to use the USB console.
1470 Once firmware is rebuilt from a serial console issue the
1471 command "setenv stdin usbtty; setenv stdout usbtty" and
1472 attach your USB cable. The Unix command "dmesg" should print
1473 it has found a new device. The environment variable usbtty
1474 can be set to gserial or cdc_acm to enable your device to
1475 appear to a USB host as a Linux gserial device or a
1476 Common Device Class Abstract Control Model serial device.
1477 If you select usbtty = gserial you should be able to enumerate
1479 # modprobe usbserial vendor=0xVendorID product=0xProductID
1480 else if using cdc_acm, simply setting the environment
1481 variable usbtty to be cdc_acm should suffice. The following
1482 might be defined in YourBoardName.h
1485 Define this to build a UDC device
1488 Define this to have a tty type of device available to
1489 talk to the UDC device
1492 Define this to enable the high speed support for usb
1493 device and usbtty. If this feature is enabled, a routine
1494 int is_usbd_high_speed(void)
1495 also needs to be defined by the driver to dynamically poll
1496 whether the enumeration has succeded at high speed or full
1499 CONFIG_SYS_CONSOLE_IS_IN_ENV
1500 Define this if you want stdin, stdout &/or stderr to
1504 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1505 Derive USB clock from external clock "blah"
1506 - CONFIG_SYS_USB_EXTC_CLK 0x02
1508 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1509 Derive USB clock from brgclk
1510 - CONFIG_SYS_USB_BRG_CLK 0x04
1512 If you have a USB-IF assigned VendorID then you may wish to
1513 define your own vendor specific values either in BoardName.h
1514 or directly in usbd_vendor_info.h. If you don't define
1515 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1516 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1517 should pretend to be a Linux device to it's target host.
1519 CONFIG_USBD_MANUFACTURER
1520 Define this string as the name of your company for
1521 - CONFIG_USBD_MANUFACTURER "my company"
1523 CONFIG_USBD_PRODUCT_NAME
1524 Define this string as the name of your product
1525 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1527 CONFIG_USBD_VENDORID
1528 Define this as your assigned Vendor ID from the USB
1529 Implementors Forum. This *must* be a genuine Vendor ID
1530 to avoid polluting the USB namespace.
1531 - CONFIG_USBD_VENDORID 0xFFFF
1533 CONFIG_USBD_PRODUCTID
1534 Define this as the unique Product ID
1536 - CONFIG_USBD_PRODUCTID 0xFFFF
1538 - ULPI Layer Support:
1539 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1540 the generic ULPI layer. The generic layer accesses the ULPI PHY
1541 via the platform viewport, so you need both the genric layer and
1542 the viewport enabled. Currently only Chipidea/ARC based
1543 viewport is supported.
1544 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1545 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1546 If your ULPI phy needs a different reference clock than the
1547 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1548 the appropriate value in Hz.
1551 The MMC controller on the Intel PXA is supported. To
1552 enable this define CONFIG_MMC. The MMC can be
1553 accessed from the boot prompt by mapping the device
1554 to physical memory similar to flash. Command line is
1555 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1556 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1559 Support for Renesas on-chip MMCIF controller
1561 CONFIG_SH_MMCIF_ADDR
1562 Define the base address of MMCIF registers
1565 Define the clock frequency for MMCIF
1568 Enable the generic MMC driver
1570 CONFIG_SUPPORT_EMMC_BOOT
1571 Enable some additional features of the eMMC boot partitions.
1573 CONFIG_SUPPORT_EMMC_RPMB
1574 Enable the commands for reading, writing and programming the
1575 key for the Replay Protection Memory Block partition in eMMC.
1577 - USB Device Firmware Update (DFU) class support:
1579 This enables the USB portion of the DFU USB class
1582 This enables the command "dfu" which is used to have
1583 U-Boot create a DFU class device via USB. This command
1584 requires that the "dfu_alt_info" environment variable be
1585 set and define the alt settings to expose to the host.
1588 This enables support for exposing (e)MMC devices via DFU.
1591 This enables support for exposing NAND devices via DFU.
1594 This enables support for exposing RAM via DFU.
1595 Note: DFU spec refer to non-volatile memory usage, but
1596 allow usages beyond the scope of spec - here RAM usage,
1597 one that would help mostly the developer.
1599 CONFIG_SYS_DFU_DATA_BUF_SIZE
1600 Dfu transfer uses a buffer before writing data to the
1601 raw storage device. Make the size (in bytes) of this buffer
1602 configurable. The size of this buffer is also configurable
1603 through the "dfu_bufsiz" environment variable.
1605 CONFIG_SYS_DFU_MAX_FILE_SIZE
1606 When updating files rather than the raw storage device,
1607 we use a static buffer to copy the file into and then write
1608 the buffer once we've been given the whole file. Define
1609 this to the maximum filesize (in bytes) for the buffer.
1610 Default is 4 MiB if undefined.
1612 DFU_DEFAULT_POLL_TIMEOUT
1613 Poll timeout [ms], is the timeout a device can send to the
1614 host. The host must wait for this timeout before sending
1615 a subsequent DFU_GET_STATUS request to the device.
1617 DFU_MANIFEST_POLL_TIMEOUT
1618 Poll timeout [ms], which the device sends to the host when
1619 entering dfuMANIFEST state. Host waits this timeout, before
1620 sending again an USB request to the device.
1622 - USB Device Android Fastboot support:
1624 This enables the command "fastboot" which enables the Android
1625 fastboot mode for the platform's USB device. Fastboot is a USB
1626 protocol for downloading images, flashing and device control
1627 used on Android devices.
1628 See doc/README.android-fastboot for more information.
1630 CONFIG_ANDROID_BOOT_IMAGE
1631 This enables support for booting images which use the Android
1632 image format header.
1634 CONFIG_USB_FASTBOOT_BUF_ADDR
1635 The fastboot protocol requires a large memory buffer for
1636 downloads. Define this to the starting RAM address to use for
1639 CONFIG_USB_FASTBOOT_BUF_SIZE
1640 The fastboot protocol requires a large memory buffer for
1641 downloads. This buffer should be as large as possible for a
1642 platform. Define this to the size available RAM for fastboot.
1644 CONFIG_FASTBOOT_FLASH
1645 The fastboot protocol includes a "flash" command for writing
1646 the downloaded image to a non-volatile storage device. Define
1647 this to enable the "fastboot flash" command.
1649 CONFIG_FASTBOOT_FLASH_MMC_DEV
1650 The fastboot "flash" command requires additional information
1651 regarding the non-volatile storage device. Define this to
1652 the eMMC device that fastboot should use to store the image.
1654 - Journaling Flash filesystem support:
1655 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1656 CONFIG_JFFS2_NAND_DEV
1657 Define these for a default partition on a NAND device
1659 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1660 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1661 Define these for a default partition on a NOR device
1663 CONFIG_SYS_JFFS_CUSTOM_PART
1664 Define this to create an own partition. You have to provide a
1665 function struct part_info* jffs2_part_info(int part_num)
1667 If you define only one JFFS2 partition you may also want to
1668 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1669 to disable the command chpart. This is the default when you
1670 have not defined a custom partition
1672 - FAT(File Allocation Table) filesystem write function support:
1675 Define this to enable support for saving memory data as a
1676 file in FAT formatted partition.
1678 This will also enable the command "fatwrite" enabling the
1679 user to write files to FAT.
1681 CBFS (Coreboot Filesystem) support
1684 Define this to enable support for reading from a Coreboot
1685 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1688 - FAT(File Allocation Table) filesystem cluster size:
1689 CONFIG_FS_FAT_MAX_CLUSTSIZE
1691 Define the max cluster size for fat operations else
1692 a default value of 65536 will be defined.
1697 Define this to enable standard (PC-Style) keyboard
1701 Standard PC keyboard driver with US (is default) and
1702 GERMAN key layout (switch via environment 'keymap=de') support.
1703 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1704 for cfb_console. Supports cursor blinking.
1707 Enables a Chrome OS keyboard using the CROS_EC interface.
1708 This uses CROS_EC to communicate with a second microcontroller
1709 which provides key scans on request.
1714 Define this to enable video support (for output to
1717 CONFIG_VIDEO_CT69000
1719 Enable Chips & Technologies 69000 Video chip
1721 CONFIG_VIDEO_SMI_LYNXEM
1722 Enable Silicon Motion SMI 712/710/810 Video chip. The
1723 video output is selected via environment 'videoout'
1724 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1727 For the CT69000 and SMI_LYNXEM drivers, videomode is
1728 selected via environment 'videomode'. Two different ways
1730 - "videomode=num" 'num' is a standard LiLo mode numbers.
1731 Following standard modes are supported (* is default):
1733 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1734 -------------+---------------------------------------------
1735 8 bits | 0x301* 0x303 0x305 0x161 0x307
1736 15 bits | 0x310 0x313 0x316 0x162 0x319
1737 16 bits | 0x311 0x314 0x317 0x163 0x31A
1738 24 bits | 0x312 0x315 0x318 ? 0x31B
1739 -------------+---------------------------------------------
1740 (i.e. setenv videomode 317; saveenv; reset;)
1742 - "videomode=bootargs" all the video parameters are parsed
1743 from the bootargs. (See drivers/video/videomodes.c)
1746 CONFIG_VIDEO_SED13806
1747 Enable Epson SED13806 driver. This driver supports 8bpp
1748 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1749 or CONFIG_VIDEO_SED13806_16BPP
1752 Enable the Freescale DIU video driver. Reference boards for
1753 SOCs that have a DIU should define this macro to enable DIU
1754 support, and should also define these other macros:
1760 CONFIG_VIDEO_SW_CURSOR
1761 CONFIG_VGA_AS_SINGLE_DEVICE
1763 CONFIG_VIDEO_BMP_LOGO
1765 The DIU driver will look for the 'video-mode' environment
1766 variable, and if defined, enable the DIU as a console during
1767 boot. See the documentation file README.video for a
1768 description of this variable.
1772 Enable the VGA video / BIOS for x86. The alternative if you
1773 are using coreboot is to use the coreboot frame buffer
1780 Define this to enable a custom keyboard support.
1781 This simply calls drv_keyboard_init() which must be
1782 defined in your board-specific files.
1783 The only board using this so far is RBC823.
1785 - LCD Support: CONFIG_LCD
1787 Define this to enable LCD support (for output to LCD
1788 display); also select one of the supported displays
1789 by defining one of these:
1793 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1795 CONFIG_NEC_NL6448AC33:
1797 NEC NL6448AC33-18. Active, color, single scan.
1799 CONFIG_NEC_NL6448BC20
1801 NEC NL6448BC20-08. 6.5", 640x480.
1802 Active, color, single scan.
1804 CONFIG_NEC_NL6448BC33_54
1806 NEC NL6448BC33-54. 10.4", 640x480.
1807 Active, color, single scan.
1811 Sharp 320x240. Active, color, single scan.
1812 It isn't 16x9, and I am not sure what it is.
1814 CONFIG_SHARP_LQ64D341
1816 Sharp LQ64D341 display, 640x480.
1817 Active, color, single scan.
1821 HLD1045 display, 640x480.
1822 Active, color, single scan.
1826 Optrex CBL50840-2 NF-FW 99 22 M5
1828 Hitachi LMG6912RPFC-00T
1832 320x240. Black & white.
1834 Normally display is black on white background; define
1835 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1837 CONFIG_LCD_ALIGNMENT
1839 Normally the LCD is page-aligned (tyically 4KB). If this is
1840 defined then the LCD will be aligned to this value instead.
1841 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1842 here, since it is cheaper to change data cache settings on
1843 a per-section basis.
1845 CONFIG_CONSOLE_SCROLL_LINES
1847 When the console need to be scrolled, this is the number of
1848 lines to scroll by. It defaults to 1. Increasing this makes
1849 the console jump but can help speed up operation when scrolling
1854 Support drawing of RLE8-compressed bitmaps on the LCD.
1858 Enables an 'i2c edid' command which can read EDID
1859 information over I2C from an attached LCD display.
1861 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1863 If this option is set, the environment is checked for
1864 a variable "splashimage". If found, the usual display
1865 of logo, copyright and system information on the LCD
1866 is suppressed and the BMP image at the address
1867 specified in "splashimage" is loaded instead. The
1868 console is redirected to the "nulldev", too. This
1869 allows for a "silent" boot where a splash screen is
1870 loaded very quickly after power-on.
1872 CONFIG_SPLASHIMAGE_GUARD
1874 If this option is set, then U-Boot will prevent the environment
1875 variable "splashimage" from being set to a problematic address
1876 (see README.displaying-bmps).
1877 This option is useful for targets where, due to alignment
1878 restrictions, an improperly aligned BMP image will cause a data
1879 abort. If you think you will not have problems with unaligned
1880 accesses (for example because your toolchain prevents them)
1881 there is no need to set this option.
1883 CONFIG_SPLASH_SCREEN_ALIGN
1885 If this option is set the splash image can be freely positioned
1886 on the screen. Environment variable "splashpos" specifies the
1887 position as "x,y". If a positive number is given it is used as
1888 number of pixel from left/top. If a negative number is given it
1889 is used as number of pixel from right/bottom. You can also
1890 specify 'm' for centering the image.
1893 setenv splashpos m,m
1894 => image at center of screen
1896 setenv splashpos 30,20
1897 => image at x = 30 and y = 20
1899 setenv splashpos -10,m
1900 => vertically centered image
1901 at x = dspWidth - bmpWidth - 9
1903 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1905 If this option is set, additionally to standard BMP
1906 images, gzipped BMP images can be displayed via the
1907 splashscreen support or the bmp command.
1909 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1911 If this option is set, 8-bit RLE compressed BMP images
1912 can be displayed via the splashscreen support or the
1915 - Do compresssing for memory range:
1918 If this option is set, it would use zlib deflate method
1919 to compress the specified memory at its best effort.
1921 - Compression support:
1924 Enabled by default to support gzip compressed images.
1928 If this option is set, support for bzip2 compressed
1929 images is included. If not, only uncompressed and gzip
1930 compressed images are supported.
1932 NOTE: the bzip2 algorithm requires a lot of RAM, so
1933 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1938 If this option is set, support for lzma compressed
1941 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1942 requires an amount of dynamic memory that is given by the
1945 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1947 Where lc and lp stand for, respectively, Literal context bits
1948 and Literal pos bits.
1950 This value is upper-bounded by 14MB in the worst case. Anyway,
1951 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1952 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1953 a very small buffer.
1955 Use the lzmainfo tool to determinate the lc and lp values and
1956 then calculate the amount of needed dynamic memory (ensuring
1957 the appropriate CONFIG_SYS_MALLOC_LEN value).
1961 If this option is set, support for LZO compressed images
1967 The address of PHY on MII bus.
1969 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1971 The clock frequency of the MII bus
1975 If this option is set, support for speed/duplex
1976 detection of gigabit PHY is included.
1978 CONFIG_PHY_RESET_DELAY
1980 Some PHY like Intel LXT971A need extra delay after
1981 reset before any MII register access is possible.
1982 For such PHY, set this option to the usec delay
1983 required. (minimum 300usec for LXT971A)
1985 CONFIG_PHY_CMD_DELAY (ppc4xx)
1987 Some PHY like Intel LXT971A need extra delay after
1988 command issued before MII status register can be read
1998 Define a default value for Ethernet address to use
1999 for the respective Ethernet interface, in case this
2000 is not determined automatically.
2005 Define a default value for the IP address to use for
2006 the default Ethernet interface, in case this is not
2007 determined through e.g. bootp.
2008 (Environment variable "ipaddr")
2010 - Server IP address:
2013 Defines a default value for the IP address of a TFTP
2014 server to contact when using the "tftboot" command.
2015 (Environment variable "serverip")
2017 CONFIG_KEEP_SERVERADDR
2019 Keeps the server's MAC address, in the env 'serveraddr'
2020 for passing to bootargs (like Linux's netconsole option)
2022 - Gateway IP address:
2025 Defines a default value for the IP address of the
2026 default router where packets to other networks are
2028 (Environment variable "gatewayip")
2033 Defines a default value for the subnet mask (or
2034 routing prefix) which is used to determine if an IP
2035 address belongs to the local subnet or needs to be
2036 forwarded through a router.
2037 (Environment variable "netmask")
2039 - Multicast TFTP Mode:
2042 Defines whether you want to support multicast TFTP as per
2043 rfc-2090; for example to work with atftp. Lets lots of targets
2044 tftp down the same boot image concurrently. Note: the Ethernet
2045 driver in use must provide a function: mcast() to join/leave a
2048 - BOOTP Recovery Mode:
2049 CONFIG_BOOTP_RANDOM_DELAY
2051 If you have many targets in a network that try to
2052 boot using BOOTP, you may want to avoid that all
2053 systems send out BOOTP requests at precisely the same
2054 moment (which would happen for instance at recovery
2055 from a power failure, when all systems will try to
2056 boot, thus flooding the BOOTP server. Defining
2057 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2058 inserted before sending out BOOTP requests. The
2059 following delays are inserted then:
2061 1st BOOTP request: delay 0 ... 1 sec
2062 2nd BOOTP request: delay 0 ... 2 sec
2063 3rd BOOTP request: delay 0 ... 4 sec
2065 BOOTP requests: delay 0 ... 8 sec
2067 CONFIG_BOOTP_ID_CACHE_SIZE
2069 BOOTP packets are uniquely identified using a 32-bit ID. The
2070 server will copy the ID from client requests to responses and
2071 U-Boot will use this to determine if it is the destination of
2072 an incoming response. Some servers will check that addresses
2073 aren't in use before handing them out (usually using an ARP
2074 ping) and therefore take up to a few hundred milliseconds to
2075 respond. Network congestion may also influence the time it
2076 takes for a response to make it back to the client. If that
2077 time is too long, U-Boot will retransmit requests. In order
2078 to allow earlier responses to still be accepted after these
2079 retransmissions, U-Boot's BOOTP client keeps a small cache of
2080 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2081 cache. The default is to keep IDs for up to four outstanding
2082 requests. Increasing this will allow U-Boot to accept offers
2083 from a BOOTP client in networks with unusually high latency.
2085 - DHCP Advanced Options:
2086 You can fine tune the DHCP functionality by defining
2087 CONFIG_BOOTP_* symbols:
2089 CONFIG_BOOTP_SUBNETMASK
2090 CONFIG_BOOTP_GATEWAY
2091 CONFIG_BOOTP_HOSTNAME
2092 CONFIG_BOOTP_NISDOMAIN
2093 CONFIG_BOOTP_BOOTPATH
2094 CONFIG_BOOTP_BOOTFILESIZE
2097 CONFIG_BOOTP_SEND_HOSTNAME
2098 CONFIG_BOOTP_NTPSERVER
2099 CONFIG_BOOTP_TIMEOFFSET
2100 CONFIG_BOOTP_VENDOREX
2101 CONFIG_BOOTP_MAY_FAIL
2103 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2104 environment variable, not the BOOTP server.
2106 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2107 after the configured retry count, the call will fail
2108 instead of starting over. This can be used to fail over
2109 to Link-local IP address configuration if the DHCP server
2112 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2113 serverip from a DHCP server, it is possible that more
2114 than one DNS serverip is offered to the client.
2115 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2116 serverip will be stored in the additional environment
2117 variable "dnsip2". The first DNS serverip is always
2118 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2121 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2122 to do a dynamic update of a DNS server. To do this, they
2123 need the hostname of the DHCP requester.
2124 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2125 of the "hostname" environment variable is passed as
2126 option 12 to the DHCP server.
2128 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2130 A 32bit value in microseconds for a delay between
2131 receiving a "DHCP Offer" and sending the "DHCP Request".
2132 This fixes a problem with certain DHCP servers that don't
2133 respond 100% of the time to a "DHCP request". E.g. On an
2134 AT91RM9200 processor running at 180MHz, this delay needed
2135 to be *at least* 15,000 usec before a Windows Server 2003
2136 DHCP server would reply 100% of the time. I recommend at
2137 least 50,000 usec to be safe. The alternative is to hope
2138 that one of the retries will be successful but note that
2139 the DHCP timeout and retry process takes a longer than
2142 - Link-local IP address negotiation:
2143 Negotiate with other link-local clients on the local network
2144 for an address that doesn't require explicit configuration.
2145 This is especially useful if a DHCP server cannot be guaranteed
2146 to exist in all environments that the device must operate.
2148 See doc/README.link-local for more information.
2151 CONFIG_CDP_DEVICE_ID
2153 The device id used in CDP trigger frames.
2155 CONFIG_CDP_DEVICE_ID_PREFIX
2157 A two character string which is prefixed to the MAC address
2162 A printf format string which contains the ascii name of
2163 the port. Normally is set to "eth%d" which sets
2164 eth0 for the first Ethernet, eth1 for the second etc.
2166 CONFIG_CDP_CAPABILITIES
2168 A 32bit integer which indicates the device capabilities;
2169 0x00000010 for a normal host which does not forwards.
2173 An ascii string containing the version of the software.
2177 An ascii string containing the name of the platform.
2181 A 32bit integer sent on the trigger.
2183 CONFIG_CDP_POWER_CONSUMPTION
2185 A 16bit integer containing the power consumption of the
2186 device in .1 of milliwatts.
2188 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2190 A byte containing the id of the VLAN.
2192 - Status LED: CONFIG_STATUS_LED
2194 Several configurations allow to display the current
2195 status using a LED. For instance, the LED will blink
2196 fast while running U-Boot code, stop blinking as
2197 soon as a reply to a BOOTP request was received, and
2198 start blinking slow once the Linux kernel is running
2199 (supported by a status LED driver in the Linux
2200 kernel). Defining CONFIG_STATUS_LED enables this
2206 The status LED can be connected to a GPIO pin.
2207 In such cases, the gpio_led driver can be used as a
2208 status LED backend implementation. Define CONFIG_GPIO_LED
2209 to include the gpio_led driver in the U-Boot binary.
2211 CONFIG_GPIO_LED_INVERTED_TABLE
2212 Some GPIO connected LEDs may have inverted polarity in which
2213 case the GPIO high value corresponds to LED off state and
2214 GPIO low value corresponds to LED on state.
2215 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2216 with a list of GPIO LEDs that have inverted polarity.
2218 - CAN Support: CONFIG_CAN_DRIVER
2220 Defining CONFIG_CAN_DRIVER enables CAN driver support
2221 on those systems that support this (optional)
2222 feature, like the TQM8xxL modules.
2224 - I2C Support: CONFIG_SYS_I2C
2226 This enable the NEW i2c subsystem, and will allow you to use
2227 i2c commands at the u-boot command line (as long as you set
2228 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2229 based realtime clock chips or other i2c devices. See
2230 common/cmd_i2c.c for a description of the command line
2233 ported i2c driver to the new framework:
2234 - drivers/i2c/soft_i2c.c:
2235 - activate first bus with CONFIG_SYS_I2C_SOFT define
2236 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2237 for defining speed and slave address
2238 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2239 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2240 for defining speed and slave address
2241 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2242 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2243 for defining speed and slave address
2244 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2245 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2246 for defining speed and slave address
2248 - drivers/i2c/fsl_i2c.c:
2249 - activate i2c driver with CONFIG_SYS_I2C_FSL
2250 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2251 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2252 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2254 - If your board supports a second fsl i2c bus, define
2255 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2256 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2257 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2260 - drivers/i2c/tegra_i2c.c:
2261 - activate this driver with CONFIG_SYS_I2C_TEGRA
2262 - This driver adds 4 i2c buses with a fix speed from
2263 100000 and the slave addr 0!
2265 - drivers/i2c/ppc4xx_i2c.c
2266 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2267 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2268 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2270 - drivers/i2c/i2c_mxc.c
2271 - activate this driver with CONFIG_SYS_I2C_MXC
2272 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2273 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2274 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2275 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2276 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2277 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2278 If thoses defines are not set, default value is 100000
2279 for speed, and 0 for slave.
2281 - drivers/i2c/rcar_i2c.c:
2282 - activate this driver with CONFIG_SYS_I2C_RCAR
2283 - This driver adds 4 i2c buses
2285 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2286 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2287 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2288 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2289 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2290 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2291 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2292 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2293 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2295 - drivers/i2c/sh_i2c.c:
2296 - activate this driver with CONFIG_SYS_I2C_SH
2297 - This driver adds from 2 to 5 i2c buses
2299 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2300 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2301 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2302 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2303 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2304 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2305 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2306 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2307 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2308 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2309 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2310 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2311 - CONFIF_SYS_I2C_SH_NUM_CONTROLLERS for nummber of i2c buses
2313 - drivers/i2c/omap24xx_i2c.c
2314 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2315 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2316 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2317 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2318 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2319 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2320 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2321 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2322 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2323 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2324 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2326 - drivers/i2c/zynq_i2c.c
2327 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2328 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2329 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2331 - drivers/i2c/s3c24x0_i2c.c:
2332 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2333 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2334 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2335 with a fix speed from 100000 and the slave addr 0!
2337 - drivers/i2c/ihs_i2c.c
2338 - activate this driver with CONFIG_SYS_I2C_IHS
2339 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2340 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2341 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2342 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2343 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2344 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2345 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2346 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2347 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2348 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2349 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2350 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2354 CONFIG_SYS_NUM_I2C_BUSES
2355 Hold the number of i2c busses you want to use. If you
2356 don't use/have i2c muxes on your i2c bus, this
2357 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2360 CONFIG_SYS_I2C_DIRECT_BUS
2361 define this, if you don't use i2c muxes on your hardware.
2362 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2365 CONFIG_SYS_I2C_MAX_HOPS
2366 define how many muxes are maximal consecutively connected
2367 on one i2c bus. If you not use i2c muxes, omit this
2370 CONFIG_SYS_I2C_BUSES
2371 hold a list of busses you want to use, only used if
2372 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2373 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2374 CONFIG_SYS_NUM_I2C_BUSES = 9:
2376 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2377 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2378 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2379 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2380 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2381 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2382 {1, {I2C_NULL_HOP}}, \
2383 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2384 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2388 bus 0 on adapter 0 without a mux
2389 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2390 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2391 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2392 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2393 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2394 bus 6 on adapter 1 without a mux
2395 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2396 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2398 If you do not have i2c muxes on your board, omit this define.
2400 - Legacy I2C Support: CONFIG_HARD_I2C
2402 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2403 provides the following compelling advantages:
2405 - more than one i2c adapter is usable
2406 - approved multibus support
2407 - better i2c mux support
2409 ** Please consider updating your I2C driver now. **
2411 These enable legacy I2C serial bus commands. Defining
2412 CONFIG_HARD_I2C will include the appropriate I2C driver
2413 for the selected CPU.
2415 This will allow you to use i2c commands at the u-boot
2416 command line (as long as you set CONFIG_CMD_I2C in
2417 CONFIG_COMMANDS) and communicate with i2c based realtime
2418 clock chips. See common/cmd_i2c.c for a description of the
2419 command line interface.
2421 CONFIG_HARD_I2C selects a hardware I2C controller.
2423 There are several other quantities that must also be
2424 defined when you define CONFIG_HARD_I2C.
2426 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2427 to be the frequency (in Hz) at which you wish your i2c bus
2428 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2429 the CPU's i2c node address).
2431 Now, the u-boot i2c code for the mpc8xx
2432 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2433 and so its address should therefore be cleared to 0 (See,
2434 eg, MPC823e User's Manual p.16-473). So, set
2435 CONFIG_SYS_I2C_SLAVE to 0.
2437 CONFIG_SYS_I2C_INIT_MPC5XXX
2439 When a board is reset during an i2c bus transfer
2440 chips might think that the current transfer is still
2441 in progress. Reset the slave devices by sending start
2442 commands until the slave device responds.
2444 That's all that's required for CONFIG_HARD_I2C.
2446 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2447 then the following macros need to be defined (examples are
2448 from include/configs/lwmon.h):
2452 (Optional). Any commands necessary to enable the I2C
2453 controller or configure ports.
2455 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2459 (Only for MPC8260 CPU). The I/O port to use (the code
2460 assumes both bits are on the same port). Valid values
2461 are 0..3 for ports A..D.
2465 The code necessary to make the I2C data line active
2466 (driven). If the data line is open collector, this
2469 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2473 The code necessary to make the I2C data line tri-stated
2474 (inactive). If the data line is open collector, this
2477 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2481 Code that returns true if the I2C data line is high,
2484 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2488 If <bit> is true, sets the I2C data line high. If it
2489 is false, it clears it (low).
2491 eg: #define I2C_SDA(bit) \
2492 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2493 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2497 If <bit> is true, sets the I2C clock line high. If it
2498 is false, it clears it (low).
2500 eg: #define I2C_SCL(bit) \
2501 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2502 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2506 This delay is invoked four times per clock cycle so this
2507 controls the rate of data transfer. The data rate thus
2508 is 1 / (I2C_DELAY * 4). Often defined to be something
2511 #define I2C_DELAY udelay(2)
2513 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2515 If your arch supports the generic GPIO framework (asm/gpio.h),
2516 then you may alternatively define the two GPIOs that are to be
2517 used as SCL / SDA. Any of the previous I2C_xxx macros will
2518 have GPIO-based defaults assigned to them as appropriate.
2520 You should define these to the GPIO value as given directly to
2521 the generic GPIO functions.
2523 CONFIG_SYS_I2C_INIT_BOARD
2525 When a board is reset during an i2c bus transfer
2526 chips might think that the current transfer is still
2527 in progress. On some boards it is possible to access
2528 the i2c SCLK line directly, either by using the
2529 processor pin as a GPIO or by having a second pin
2530 connected to the bus. If this option is defined a
2531 custom i2c_init_board() routine in boards/xxx/board.c
2532 is run early in the boot sequence.
2534 CONFIG_SYS_I2C_BOARD_LATE_INIT
2536 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2537 defined a custom i2c_board_late_init() routine in
2538 boards/xxx/board.c is run AFTER the operations in i2c_init()
2539 is completed. This callpoint can be used to unreset i2c bus
2540 using CPU i2c controller register accesses for CPUs whose i2c
2541 controller provide such a method. It is called at the end of
2542 i2c_init() to allow i2c_init operations to setup the i2c bus
2543 controller on the CPU (e.g. setting bus speed & slave address).
2545 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2547 This option enables configuration of bi_iic_fast[] flags
2548 in u-boot bd_info structure based on u-boot environment
2549 variable "i2cfast". (see also i2cfast)
2551 CONFIG_I2C_MULTI_BUS
2553 This option allows the use of multiple I2C buses, each of which
2554 must have a controller. At any point in time, only one bus is
2555 active. To switch to a different bus, use the 'i2c dev' command.
2556 Note that bus numbering is zero-based.
2558 CONFIG_SYS_I2C_NOPROBES
2560 This option specifies a list of I2C devices that will be skipped
2561 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2562 is set, specify a list of bus-device pairs. Otherwise, specify
2563 a 1D array of device addresses
2566 #undef CONFIG_I2C_MULTI_BUS
2567 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2569 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2571 #define CONFIG_I2C_MULTI_BUS
2572 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2574 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2576 CONFIG_SYS_SPD_BUS_NUM
2578 If defined, then this indicates the I2C bus number for DDR SPD.
2579 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2581 CONFIG_SYS_RTC_BUS_NUM
2583 If defined, then this indicates the I2C bus number for the RTC.
2584 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2586 CONFIG_SYS_DTT_BUS_NUM
2588 If defined, then this indicates the I2C bus number for the DTT.
2589 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2591 CONFIG_SYS_I2C_DTT_ADDR:
2593 If defined, specifies the I2C address of the DTT device.
2594 If not defined, then U-Boot uses predefined value for
2595 specified DTT device.
2597 CONFIG_SOFT_I2C_READ_REPEATED_START
2599 defining this will force the i2c_read() function in
2600 the soft_i2c driver to perform an I2C repeated start
2601 between writing the address pointer and reading the
2602 data. If this define is omitted the default behaviour
2603 of doing a stop-start sequence will be used. Most I2C
2604 devices can use either method, but some require one or
2607 - SPI Support: CONFIG_SPI
2609 Enables SPI driver (so far only tested with
2610 SPI EEPROM, also an instance works with Crystal A/D and
2611 D/As on the SACSng board)
2615 Enables the driver for SPI controller on SuperH. Currently
2616 only SH7757 is supported.
2620 Enables extended (16-bit) SPI EEPROM addressing.
2621 (symmetrical to CONFIG_I2C_X)
2625 Enables a software (bit-bang) SPI driver rather than
2626 using hardware support. This is a general purpose
2627 driver that only requires three general I/O port pins
2628 (two outputs, one input) to function. If this is
2629 defined, the board configuration must define several
2630 SPI configuration items (port pins to use, etc). For
2631 an example, see include/configs/sacsng.h.
2635 Enables a hardware SPI driver for general-purpose reads
2636 and writes. As with CONFIG_SOFT_SPI, the board configuration
2637 must define a list of chip-select function pointers.
2638 Currently supported on some MPC8xxx processors. For an
2639 example, see include/configs/mpc8349emds.h.
2643 Enables the driver for the SPI controllers on i.MX and MXC
2644 SoCs. Currently i.MX31/35/51 are supported.
2646 CONFIG_SYS_SPI_MXC_WAIT
2647 Timeout for waiting until spi transfer completed.
2648 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2650 - FPGA Support: CONFIG_FPGA
2652 Enables FPGA subsystem.
2654 CONFIG_FPGA_<vendor>
2656 Enables support for specific chip vendors.
2659 CONFIG_FPGA_<family>
2661 Enables support for FPGA family.
2662 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2666 Specify the number of FPGA devices to support.
2668 CONFIG_CMD_FPGA_LOADMK
2670 Enable support for fpga loadmk command
2672 CONFIG_CMD_FPGA_LOADP
2674 Enable support for fpga loadp command - load partial bitstream
2676 CONFIG_CMD_FPGA_LOADBP
2678 Enable support for fpga loadbp command - load partial bitstream
2681 CONFIG_SYS_FPGA_PROG_FEEDBACK
2683 Enable printing of hash marks during FPGA configuration.
2685 CONFIG_SYS_FPGA_CHECK_BUSY
2687 Enable checks on FPGA configuration interface busy
2688 status by the configuration function. This option
2689 will require a board or device specific function to
2694 If defined, a function that provides delays in the FPGA
2695 configuration driver.
2697 CONFIG_SYS_FPGA_CHECK_CTRLC
2698 Allow Control-C to interrupt FPGA configuration
2700 CONFIG_SYS_FPGA_CHECK_ERROR
2702 Check for configuration errors during FPGA bitfile
2703 loading. For example, abort during Virtex II
2704 configuration if the INIT_B line goes low (which
2705 indicated a CRC error).
2707 CONFIG_SYS_FPGA_WAIT_INIT
2709 Maximum time to wait for the INIT_B line to deassert
2710 after PROB_B has been deasserted during a Virtex II
2711 FPGA configuration sequence. The default time is 500
2714 CONFIG_SYS_FPGA_WAIT_BUSY
2716 Maximum time to wait for BUSY to deassert during
2717 Virtex II FPGA configuration. The default is 5 ms.
2719 CONFIG_SYS_FPGA_WAIT_CONFIG
2721 Time to wait after FPGA configuration. The default is
2724 - Configuration Management:
2727 If defined, this string will be added to the U-Boot
2728 version information (U_BOOT_VERSION)
2730 - Vendor Parameter Protection:
2732 U-Boot considers the values of the environment
2733 variables "serial#" (Board Serial Number) and
2734 "ethaddr" (Ethernet Address) to be parameters that
2735 are set once by the board vendor / manufacturer, and
2736 protects these variables from casual modification by
2737 the user. Once set, these variables are read-only,
2738 and write or delete attempts are rejected. You can
2739 change this behaviour:
2741 If CONFIG_ENV_OVERWRITE is #defined in your config
2742 file, the write protection for vendor parameters is
2743 completely disabled. Anybody can change or delete
2746 Alternatively, if you #define _both_ CONFIG_ETHADDR
2747 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2748 Ethernet address is installed in the environment,
2749 which can be changed exactly ONCE by the user. [The
2750 serial# is unaffected by this, i. e. it remains
2753 The same can be accomplished in a more flexible way
2754 for any variable by configuring the type of access
2755 to allow for those variables in the ".flags" variable
2756 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2761 Define this variable to enable the reservation of
2762 "protected RAM", i. e. RAM which is not overwritten
2763 by U-Boot. Define CONFIG_PRAM to hold the number of
2764 kB you want to reserve for pRAM. You can overwrite
2765 this default value by defining an environment
2766 variable "pram" to the number of kB you want to
2767 reserve. Note that the board info structure will
2768 still show the full amount of RAM. If pRAM is
2769 reserved, a new environment variable "mem" will
2770 automatically be defined to hold the amount of
2771 remaining RAM in a form that can be passed as boot
2772 argument to Linux, for instance like that:
2774 setenv bootargs ... mem=\${mem}
2777 This way you can tell Linux not to use this memory,
2778 either, which results in a memory region that will
2779 not be affected by reboots.
2781 *WARNING* If your board configuration uses automatic
2782 detection of the RAM size, you must make sure that
2783 this memory test is non-destructive. So far, the
2784 following board configurations are known to be
2787 IVMS8, IVML24, SPD8xx, TQM8xxL,
2788 HERMES, IP860, RPXlite, LWMON,
2791 - Access to physical memory region (> 4GB)
2792 Some basic support is provided for operations on memory not
2793 normally accessible to U-Boot - e.g. some architectures
2794 support access to more than 4GB of memory on 32-bit
2795 machines using physical address extension or similar.
2796 Define CONFIG_PHYSMEM to access this basic support, which
2797 currently only supports clearing the memory.
2802 Define this variable to stop the system in case of a
2803 fatal error, so that you have to reset it manually.
2804 This is probably NOT a good idea for an embedded
2805 system where you want the system to reboot
2806 automatically as fast as possible, but it may be
2807 useful during development since you can try to debug
2808 the conditions that lead to the situation.
2810 CONFIG_NET_RETRY_COUNT
2812 This variable defines the number of retries for
2813 network operations like ARP, RARP, TFTP, or BOOTP
2814 before giving up the operation. If not defined, a
2815 default value of 5 is used.
2819 Timeout waiting for an ARP reply in milliseconds.
2823 Timeout in milliseconds used in NFS protocol.
2824 If you encounter "ERROR: Cannot umount" in nfs command,
2825 try longer timeout such as
2826 #define CONFIG_NFS_TIMEOUT 10000UL
2828 - Command Interpreter:
2829 CONFIG_AUTO_COMPLETE
2831 Enable auto completion of commands using TAB.
2833 CONFIG_SYS_HUSH_PARSER
2835 Define this variable to enable the "hush" shell (from
2836 Busybox) as command line interpreter, thus enabling
2837 powerful command line syntax like
2838 if...then...else...fi conditionals or `&&' and '||'
2839 constructs ("shell scripts").
2841 If undefined, you get the old, much simpler behaviour
2842 with a somewhat smaller memory footprint.
2845 CONFIG_SYS_PROMPT_HUSH_PS2
2847 This defines the secondary prompt string, which is
2848 printed when the command interpreter needs more input
2849 to complete a command. Usually "> ".
2853 In the current implementation, the local variables
2854 space and global environment variables space are
2855 separated. Local variables are those you define by
2856 simply typing `name=value'. To access a local
2857 variable later on, you have write `$name' or
2858 `${name}'; to execute the contents of a variable
2859 directly type `$name' at the command prompt.
2861 Global environment variables are those you use
2862 setenv/printenv to work with. To run a command stored
2863 in such a variable, you need to use the run command,
2864 and you must not use the '$' sign to access them.
2866 To store commands and special characters in a
2867 variable, please use double quotation marks
2868 surrounding the whole text of the variable, instead
2869 of the backslashes before semicolons and special
2872 - Commandline Editing and History:
2873 CONFIG_CMDLINE_EDITING
2875 Enable editing and History functions for interactive
2876 commandline input operations
2878 - Default Environment:
2879 CONFIG_EXTRA_ENV_SETTINGS
2881 Define this to contain any number of null terminated
2882 strings (variable = value pairs) that will be part of
2883 the default environment compiled into the boot image.
2885 For example, place something like this in your
2886 board's config file:
2888 #define CONFIG_EXTRA_ENV_SETTINGS \
2892 Warning: This method is based on knowledge about the
2893 internal format how the environment is stored by the
2894 U-Boot code. This is NOT an official, exported
2895 interface! Although it is unlikely that this format
2896 will change soon, there is no guarantee either.
2897 You better know what you are doing here.
2899 Note: overly (ab)use of the default environment is
2900 discouraged. Make sure to check other ways to preset
2901 the environment like the "source" command or the
2904 CONFIG_ENV_VARS_UBOOT_CONFIG
2906 Define this in order to add variables describing the
2907 U-Boot build configuration to the default environment.
2908 These will be named arch, cpu, board, vendor, and soc.
2910 Enabling this option will cause the following to be defined:
2918 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2920 Define this in order to add variables describing certain
2921 run-time determined information about the hardware to the
2922 environment. These will be named board_name, board_rev.
2924 CONFIG_DELAY_ENVIRONMENT
2926 Normally the environment is loaded when the board is
2927 intialised so that it is available to U-Boot. This inhibits
2928 that so that the environment is not available until
2929 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2930 this is instead controlled by the value of
2931 /config/load-environment.
2933 - DataFlash Support:
2934 CONFIG_HAS_DATAFLASH
2936 Defining this option enables DataFlash features and
2937 allows to read/write in Dataflash via the standard
2940 - Serial Flash support
2943 Defining this option enables SPI flash commands
2944 'sf probe/read/write/erase/update'.
2946 Usage requires an initial 'probe' to define the serial
2947 flash parameters, followed by read/write/erase/update
2950 The following defaults may be provided by the platform
2951 to handle the common case when only a single serial
2952 flash is present on the system.
2954 CONFIG_SF_DEFAULT_BUS Bus identifier
2955 CONFIG_SF_DEFAULT_CS Chip-select
2956 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2957 CONFIG_SF_DEFAULT_SPEED in Hz
2961 Define this option to include a destructive SPI flash
2964 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2966 Define this option to use the Bank addr/Extended addr
2967 support on SPI flashes which has size > 16Mbytes.
2969 CONFIG_SF_DUAL_FLASH Dual flash memories
2971 Define this option to use dual flash support where two flash
2972 memories can be connected with a given cs line.
2973 currently Xilinx Zynq qspi support these type of connections.
2975 CONFIG_SYS_SPI_ST_ENABLE_WP_PIN
2976 enable the W#/Vpp signal to disable writing to the status
2977 register on ST MICRON flashes like the N25Q128.
2978 The status register write enable/disable bit, combined with
2979 the W#/VPP signal provides hardware data protection for the
2980 device as follows: When the enable/disable bit is set to 1,
2981 and the W#/VPP signal is driven LOW, the status register
2982 nonvolatile bits become read-only and the WRITE STATUS REGISTER
2983 operation will not execute. The only way to exit this
2984 hardware-protected mode is to drive W#/VPP HIGH.
2986 - SystemACE Support:
2989 Adding this option adds support for Xilinx SystemACE
2990 chips attached via some sort of local bus. The address
2991 of the chip must also be defined in the
2992 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2994 #define CONFIG_SYSTEMACE
2995 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2997 When SystemACE support is added, the "ace" device type
2998 becomes available to the fat commands, i.e. fatls.
3000 - TFTP Fixed UDP Port:
3003 If this is defined, the environment variable tftpsrcp
3004 is used to supply the TFTP UDP source port value.
3005 If tftpsrcp isn't defined, the normal pseudo-random port
3006 number generator is used.
3008 Also, the environment variable tftpdstp is used to supply
3009 the TFTP UDP destination port value. If tftpdstp isn't
3010 defined, the normal port 69 is used.
3012 The purpose for tftpsrcp is to allow a TFTP server to
3013 blindly start the TFTP transfer using the pre-configured
3014 target IP address and UDP port. This has the effect of
3015 "punching through" the (Windows XP) firewall, allowing
3016 the remainder of the TFTP transfer to proceed normally.
3017 A better solution is to properly configure the firewall,
3018 but sometimes that is not allowed.
3023 This enables a generic 'hash' command which can produce
3024 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3028 Enable the hash verify command (hash -v). This adds to code
3031 CONFIG_SHA1 - support SHA1 hashing
3032 CONFIG_SHA256 - support SHA256 hashing
3034 Note: There is also a sha1sum command, which should perhaps
3035 be deprecated in favour of 'hash sha1'.
3037 - Freescale i.MX specific commands:
3038 CONFIG_CMD_HDMIDETECT
3039 This enables 'hdmidet' command which returns true if an
3040 HDMI monitor is detected. This command is i.MX 6 specific.
3043 This enables the 'bmode' (bootmode) command for forcing
3044 a boot from specific media.
3046 This is useful for forcing the ROM's usb downloader to
3047 activate upon a watchdog reset which is nice when iterating
3048 on U-Boot. Using the reset button or running bmode normal
3049 will set it back to normal. This command currently
3050 supports i.MX53 and i.MX6.
3055 This enables the RSA algorithm used for FIT image verification
3056 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
3058 The signing part is build into mkimage regardless of this
3061 - bootcount support:
3062 CONFIG_BOOTCOUNT_LIMIT
3064 This enables the bootcounter support, see:
3065 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3068 enable special bootcounter support on at91sam9xe based boards.
3070 enable special bootcounter support on blackfin based boards.
3072 enable special bootcounter support on da850 based boards.
3073 CONFIG_BOOTCOUNT_RAM
3074 enable support for the bootcounter in RAM
3075 CONFIG_BOOTCOUNT_I2C
3076 enable support for the bootcounter on an i2c (like RTC) device.
3077 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3078 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3080 CONFIG_BOOTCOUNT_ALEN = address len
3082 - Show boot progress:
3083 CONFIG_SHOW_BOOT_PROGRESS
3085 Defining this option allows to add some board-
3086 specific code (calling a user-provided function
3087 "show_boot_progress(int)") that enables you to show
3088 the system's boot progress on some display (for
3089 example, some LED's) on your board. At the moment,
3090 the following checkpoints are implemented:
3092 - Detailed boot stage timing
3094 Define this option to get detailed timing of each stage
3095 of the boot process.
3097 CONFIG_BOOTSTAGE_USER_COUNT
3098 This is the number of available user bootstage records.
3099 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
3100 a new ID will be allocated from this stash. If you exceed
3101 the limit, recording will stop.
3103 CONFIG_BOOTSTAGE_REPORT
3104 Define this to print a report before boot, similar to this:
3106 Timer summary in microseconds:
3109 3,575,678 3,575,678 board_init_f start
3110 3,575,695 17 arch_cpu_init A9
3111 3,575,777 82 arch_cpu_init done
3112 3,659,598 83,821 board_init_r start
3113 3,910,375 250,777 main_loop
3114 29,916,167 26,005,792 bootm_start
3115 30,361,327 445,160 start_kernel
3117 CONFIG_CMD_BOOTSTAGE
3118 Add a 'bootstage' command which supports printing a report
3119 and un/stashing of bootstage data.
3121 CONFIG_BOOTSTAGE_FDT
3122 Stash the bootstage information in the FDT. A root 'bootstage'
3123 node is created with each bootstage id as a child. Each child
3124 has a 'name' property and either 'mark' containing the
3125 mark time in microsecond, or 'accum' containing the
3126 accumulated time for that bootstage id in microseconds.
3131 name = "board_init_f";
3140 Code in the Linux kernel can find this in /proc/devicetree.
3142 Legacy uImage format:
3145 1 common/cmd_bootm.c before attempting to boot an image
3146 -1 common/cmd_bootm.c Image header has bad magic number
3147 2 common/cmd_bootm.c Image header has correct magic number
3148 -2 common/cmd_bootm.c Image header has bad checksum
3149 3 common/cmd_bootm.c Image header has correct checksum
3150 -3 common/cmd_bootm.c Image data has bad checksum
3151 4 common/cmd_bootm.c Image data has correct checksum
3152 -4 common/cmd_bootm.c Image is for unsupported architecture
3153 5 common/cmd_bootm.c Architecture check OK
3154 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3155 6 common/cmd_bootm.c Image Type check OK
3156 -6 common/cmd_bootm.c gunzip uncompression error
3157 -7 common/cmd_bootm.c Unimplemented compression type
3158 7 common/cmd_bootm.c Uncompression OK
3159 8 common/cmd_bootm.c No uncompress/copy overwrite error
3160 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3162 9 common/image.c Start initial ramdisk verification
3163 -10 common/image.c Ramdisk header has bad magic number
3164 -11 common/image.c Ramdisk header has bad checksum
3165 10 common/image.c Ramdisk header is OK
3166 -12 common/image.c Ramdisk data has bad checksum
3167 11 common/image.c Ramdisk data has correct checksum
3168 12 common/image.c Ramdisk verification complete, start loading
3169 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3170 13 common/image.c Start multifile image verification
3171 14 common/image.c No initial ramdisk, no multifile, continue.
3173 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3175 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3176 -31 post/post.c POST test failed, detected by post_output_backlog()
3177 -32 post/post.c POST test failed, detected by post_run_single()
3179 34 common/cmd_doc.c before loading a Image from a DOC device
3180 -35 common/cmd_doc.c Bad usage of "doc" command
3181 35 common/cmd_doc.c correct usage of "doc" command
3182 -36 common/cmd_doc.c No boot device
3183 36 common/cmd_doc.c correct boot device
3184 -37 common/cmd_doc.c Unknown Chip ID on boot device
3185 37 common/cmd_doc.c correct chip ID found, device available
3186 -38 common/cmd_doc.c Read Error on boot device
3187 38 common/cmd_doc.c reading Image header from DOC device OK
3188 -39 common/cmd_doc.c Image header has bad magic number
3189 39 common/cmd_doc.c Image header has correct magic number
3190 -40 common/cmd_doc.c Error reading Image from DOC device
3191 40 common/cmd_doc.c Image header has correct magic number
3192 41 common/cmd_ide.c before loading a Image from a IDE device
3193 -42 common/cmd_ide.c Bad usage of "ide" command
3194 42 common/cmd_ide.c correct usage of "ide" command
3195 -43 common/cmd_ide.c No boot device
3196 43 common/cmd_ide.c boot device found
3197 -44 common/cmd_ide.c Device not available
3198 44 common/cmd_ide.c Device available
3199 -45 common/cmd_ide.c wrong partition selected
3200 45 common/cmd_ide.c partition selected
3201 -46 common/cmd_ide.c Unknown partition table
3202 46 common/cmd_ide.c valid partition table found
3203 -47 common/cmd_ide.c Invalid partition type
3204 47 common/cmd_ide.c correct partition type
3205 -48 common/cmd_ide.c Error reading Image Header on boot device
3206 48 common/cmd_ide.c reading Image Header from IDE device OK
3207 -49 common/cmd_ide.c Image header has bad magic number
3208 49 common/cmd_ide.c Image header has correct magic number
3209 -50 common/cmd_ide.c Image header has bad checksum
3210 50 common/cmd_ide.c Image header has correct checksum
3211 -51 common/cmd_ide.c Error reading Image from IDE device
3212 51 common/cmd_ide.c reading Image from IDE device OK
3213 52 common/cmd_nand.c before loading a Image from a NAND device
3214 -53 common/cmd_nand.c Bad usage of "nand" command
3215 53 common/cmd_nand.c correct usage of "nand" command
3216 -54 common/cmd_nand.c No boot device
3217 54 common/cmd_nand.c boot device found
3218 -55 common/cmd_nand.c Unknown Chip ID on boot device
3219 55 common/cmd_nand.c correct chip ID found, device available
3220 -56 common/cmd_nand.c Error reading Image Header on boot device
3221 56 common/cmd_nand.c reading Image Header from NAND device OK
3222 -57 common/cmd_nand.c Image header has bad magic number
3223 57 common/cmd_nand.c Image header has correct magic number
3224 -58 common/cmd_nand.c Error reading Image from NAND device
3225 58 common/cmd_nand.c reading Image from NAND device OK
3227 -60 common/env_common.c Environment has a bad CRC, using default
3229 64 net/eth.c starting with Ethernet configuration.
3230 -64 net/eth.c no Ethernet found.
3231 65 net/eth.c Ethernet found.
3233 -80 common/cmd_net.c usage wrong
3234 80 common/cmd_net.c before calling NetLoop()
3235 -81 common/cmd_net.c some error in NetLoop() occurred
3236 81 common/cmd_net.c NetLoop() back without error
3237 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3238 82 common/cmd_net.c trying automatic boot
3239 83 common/cmd_net.c running "source" command
3240 -83 common/cmd_net.c some error in automatic boot or "source" command
3241 84 common/cmd_net.c end without errors
3246 100 common/cmd_bootm.c Kernel FIT Image has correct format
3247 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3248 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3249 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3250 102 common/cmd_bootm.c Kernel unit name specified
3251 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3252 103 common/cmd_bootm.c Found configuration node
3253 104 common/cmd_bootm.c Got kernel subimage node offset
3254 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3255 105 common/cmd_bootm.c Kernel subimage hash verification OK
3256 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3257 106 common/cmd_bootm.c Architecture check OK
3258 -106 common/cmd_bootm.c Kernel subimage has wrong type
3259 107 common/cmd_bootm.c Kernel subimage type OK
3260 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3261 108 common/cmd_bootm.c Got kernel subimage data/size
3262 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3263 -109 common/cmd_bootm.c Can't get kernel subimage type
3264 -110 common/cmd_bootm.c Can't get kernel subimage comp
3265 -111 common/cmd_bootm.c Can't get kernel subimage os
3266 -112 common/cmd_bootm.c Can't get kernel subimage load address
3267 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3269 120 common/image.c Start initial ramdisk verification
3270 -120 common/image.c Ramdisk FIT image has incorrect format
3271 121 common/image.c Ramdisk FIT image has correct format
3272 122 common/image.c No ramdisk subimage unit name, using configuration
3273 -122 common/image.c Can't get configuration for ramdisk subimage
3274 123 common/image.c Ramdisk unit name specified
3275 -124 common/image.c Can't get ramdisk subimage node offset
3276 125 common/image.c Got ramdisk subimage node offset
3277 -125 common/image.c Ramdisk subimage hash verification failed
3278 126 common/image.c Ramdisk subimage hash verification OK
3279 -126 common/image.c Ramdisk subimage for unsupported architecture
3280 127 common/image.c Architecture check OK
3281 -127 common/image.c Can't get ramdisk subimage data/size
3282 128 common/image.c Got ramdisk subimage data/size
3283 129 common/image.c Can't get ramdisk load address
3284 -129 common/image.c Got ramdisk load address
3286 -130 common/cmd_doc.c Incorrect FIT image format
3287 131 common/cmd_doc.c FIT image format OK
3289 -140 common/cmd_ide.c Incorrect FIT image format
3290 141 common/cmd_ide.c FIT image format OK
3292 -150 common/cmd_nand.c Incorrect FIT image format
3293 151 common/cmd_nand.c FIT image format OK
3295 - legacy image format:
3296 CONFIG_IMAGE_FORMAT_LEGACY
3297 enables the legacy image format support in U-Boot.
3300 enabled if CONFIG_FIT_SIGNATURE is not defined.
3302 CONFIG_DISABLE_IMAGE_LEGACY
3303 disable the legacy image format
3305 This define is introduced, as the legacy image format is
3306 enabled per default for backward compatibility.
3308 - FIT image support:
3310 Enable support for the FIT uImage format.
3312 CONFIG_FIT_BEST_MATCH
3313 When no configuration is explicitly selected, default to the
3314 one whose fdt's compatibility field best matches that of
3315 U-Boot itself. A match is considered "best" if it matches the
3316 most specific compatibility entry of U-Boot's fdt's root node.
3317 The order of entries in the configuration's fdt is ignored.
3319 CONFIG_FIT_SIGNATURE
3320 This option enables signature verification of FIT uImages,
3321 using a hash signed and verified using RSA. See
3322 doc/uImage.FIT/signature.txt for more details.
3324 WARNING: When relying on signed FIT images with required
3325 signature check the legacy image format is default
3326 disabled. If a board need legacy image format support
3327 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3329 CONFIG_FIT_DISABLE_SHA256
3330 Supporting SHA256 hashes has quite an impact on binary size.
3331 For constrained systems sha256 hash support can be disabled
3334 - Standalone program support:
3335 CONFIG_STANDALONE_LOAD_ADDR
3337 This option defines a board specific value for the
3338 address where standalone program gets loaded, thus
3339 overwriting the architecture dependent default
3342 - Frame Buffer Address:
3345 Define CONFIG_FB_ADDR if you want to use specific
3346 address for frame buffer. This is typically the case
3347 when using a graphics controller has separate video
3348 memory. U-Boot will then place the frame buffer at
3349 the given address instead of dynamically reserving it
3350 in system RAM by calling lcd_setmem(), which grabs
3351 the memory for the frame buffer depending on the
3352 configured panel size.
3354 Please see board_init_f function.
3356 - Automatic software updates via TFTP server
3358 CONFIG_UPDATE_TFTP_CNT_MAX
3359 CONFIG_UPDATE_TFTP_MSEC_MAX
3361 These options enable and control the auto-update feature;
3362 for a more detailed description refer to doc/README.update.
3364 - MTD Support (mtdparts command, UBI support)
3367 Adds the MTD device infrastructure from the Linux kernel.
3368 Needed for mtdparts command support.
3370 CONFIG_MTD_PARTITIONS
3372 Adds the MTD partitioning infrastructure from the Linux
3373 kernel. Needed for UBI support.
3375 CONFIG_MTD_NAND_VERIFY_WRITE
3376 verify if the written data is correct reread.
3381 Adds commands for interacting with MTD partitions formatted
3382 with the UBI flash translation layer
3384 Requires also defining CONFIG_RBTREE
3386 CONFIG_UBI_SILENCE_MSG
3388 Make the verbose messages from UBI stop printing. This leaves
3389 warnings and errors enabled.
3392 CONFIG_MTD_UBI_WL_THRESHOLD
3393 This parameter defines the maximum difference between the highest
3394 erase counter value and the lowest erase counter value of eraseblocks
3395 of UBI devices. When this threshold is exceeded, UBI starts performing
3396 wear leveling by means of moving data from eraseblock with low erase
3397 counter to eraseblocks with high erase counter.
3399 The default value should be OK for SLC NAND flashes, NOR flashes and
3400 other flashes which have eraseblock life-cycle 100000 or more.
3401 However, in case of MLC NAND flashes which typically have eraseblock
3402 life-cycle less than 10000, the threshold should be lessened (e.g.,
3403 to 128 or 256, although it does not have to be power of 2).
3407 CONFIG_MTD_UBI_BEB_LIMIT
3408 This option specifies the maximum bad physical eraseblocks UBI
3409 expects on the MTD device (per 1024 eraseblocks). If the
3410 underlying flash does not admit of bad eraseblocks (e.g. NOR
3411 flash), this value is ignored.
3413 NAND datasheets often specify the minimum and maximum NVM
3414 (Number of Valid Blocks) for the flashes' endurance lifetime.
3415 The maximum expected bad eraseblocks per 1024 eraseblocks
3416 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3417 which gives 20 for most NANDs (MaxNVB is basically the total
3418 count of eraseblocks on the chip).
3420 To put it differently, if this value is 20, UBI will try to
3421 reserve about 1.9% of physical eraseblocks for bad blocks
3422 handling. And that will be 1.9% of eraseblocks on the entire
3423 NAND chip, not just the MTD partition UBI attaches. This means
3424 that if you have, say, a NAND flash chip admits maximum 40 bad
3425 eraseblocks, and it is split on two MTD partitions of the same
3426 size, UBI will reserve 40 eraseblocks when attaching a
3431 CONFIG_MTD_UBI_FASTMAP
3432 Fastmap is a mechanism which allows attaching an UBI device
3433 in nearly constant time. Instead of scanning the whole MTD device it
3434 only has to locate a checkpoint (called fastmap) on the device.
3435 The on-flash fastmap contains all information needed to attach
3436 the device. Using fastmap makes only sense on large devices where
3437 attaching by scanning takes long. UBI will not automatically install
3438 a fastmap on old images, but you can set the UBI parameter
3439 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3440 that fastmap-enabled images are still usable with UBI implementations
3441 without fastmap support. On typical flash devices the whole fastmap
3442 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3444 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3445 Set this parameter to enable fastmap automatically on images
3452 Adds commands for interacting with UBI volumes formatted as
3453 UBIFS. UBIFS is read-only in u-boot.
3455 Requires UBI support as well as CONFIG_LZO
3457 CONFIG_UBIFS_SILENCE_MSG
3459 Make the verbose messages from UBIFS stop printing. This leaves
3460 warnings and errors enabled.
3464 Enable building of SPL globally.
3467 LDSCRIPT for linking the SPL binary.
3469 CONFIG_SPL_MAX_FOOTPRINT
3470 Maximum size in memory allocated to the SPL, BSS included.
3471 When defined, the linker checks that the actual memory
3472 used by SPL from _start to __bss_end does not exceed it.
3473 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3474 must not be both defined at the same time.
3477 Maximum size of the SPL image (text, data, rodata, and
3478 linker lists sections), BSS excluded.
3479 When defined, the linker checks that the actual size does
3482 CONFIG_SPL_TEXT_BASE
3483 TEXT_BASE for linking the SPL binary.
3485 CONFIG_SPL_RELOC_TEXT_BASE
3486 Address to relocate to. If unspecified, this is equal to
3487 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3489 CONFIG_SPL_BSS_START_ADDR
3490 Link address for the BSS within the SPL binary.
3492 CONFIG_SPL_BSS_MAX_SIZE
3493 Maximum size in memory allocated to the SPL BSS.
3494 When defined, the linker checks that the actual memory used
3495 by SPL from __bss_start to __bss_end does not exceed it.
3496 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3497 must not be both defined at the same time.
3500 Adress of the start of the stack SPL will use
3502 CONFIG_SPL_RELOC_STACK
3503 Adress of the start of the stack SPL will use after
3504 relocation. If unspecified, this is equal to
3507 CONFIG_SYS_SPL_MALLOC_START
3508 Starting address of the malloc pool used in SPL.
3510 CONFIG_SYS_SPL_MALLOC_SIZE
3511 The size of the malloc pool used in SPL.
3513 CONFIG_SPL_FRAMEWORK
3514 Enable the SPL framework under common/. This framework
3515 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3516 NAND loading of the Linux Kernel.
3519 Enable booting directly to an OS from SPL.
3520 See also: doc/README.falcon
3522 CONFIG_SPL_DISPLAY_PRINT
3523 For ARM, enable an optional function to print more information
3524 about the running system.
3526 CONFIG_SPL_INIT_MINIMAL
3527 Arch init code should be built for a very small image
3529 CONFIG_SPL_LIBCOMMON_SUPPORT
3530 Support for common/libcommon.o in SPL binary
3532 CONFIG_SPL_LIBDISK_SUPPORT
3533 Support for disk/libdisk.o in SPL binary
3535 CONFIG_SPL_I2C_SUPPORT
3536 Support for drivers/i2c/libi2c.o in SPL binary
3538 CONFIG_SPL_GPIO_SUPPORT
3539 Support for drivers/gpio/libgpio.o in SPL binary
3541 CONFIG_SPL_MMC_SUPPORT
3542 Support for drivers/mmc/libmmc.o in SPL binary
3544 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3545 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3546 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3547 Address, size and partition on the MMC to load U-Boot from
3548 when the MMC is being used in raw mode.
3550 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3551 Sector to load kernel uImage from when MMC is being
3552 used in raw mode (for Falcon mode)
3554 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3555 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3556 Sector and number of sectors to load kernel argument
3557 parameters from when MMC is being used in raw mode
3560 CONFIG_SPL_FAT_SUPPORT
3561 Support for fs/fat/libfat.o in SPL binary
3563 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3564 Filename to read to load U-Boot when reading from FAT
3566 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3567 Filename to read to load kernel uImage when reading
3568 from FAT (for Falcon mode)
3570 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3571 Filename to read to load kernel argument parameters
3572 when reading from FAT (for Falcon mode)
3574 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3575 Set this for NAND SPL on PPC mpc83xx targets, so that
3576 start.S waits for the rest of the SPL to load before
3577 continuing (the hardware starts execution after just
3578 loading the first page rather than the full 4K).
3580 CONFIG_SPL_SKIP_RELOCATE
3581 Avoid SPL relocation
3583 CONFIG_SPL_NAND_BASE
3584 Include nand_base.c in the SPL. Requires
3585 CONFIG_SPL_NAND_DRIVERS.
3587 CONFIG_SPL_NAND_DRIVERS
3588 SPL uses normal NAND drivers, not minimal drivers.
3591 Include standard software ECC in the SPL
3593 CONFIG_SPL_NAND_SIMPLE
3594 Support for NAND boot using simple NAND drivers that
3595 expose the cmd_ctrl() interface.
3597 CONFIG_SPL_MTD_SUPPORT
3598 Support for the MTD subsystem within SPL. Useful for
3599 environment on NAND support within SPL.
3601 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3602 Set for the SPL on PPC mpc8xxx targets, support for
3603 drivers/ddr/fsl/libddr.o in SPL binary.
3605 CONFIG_SPL_COMMON_INIT_DDR
3606 Set for common ddr init with serial presence detect in
3609 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3610 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3611 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3612 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3613 CONFIG_SYS_NAND_ECCBYTES
3614 Defines the size and behavior of the NAND that SPL uses
3617 CONFIG_SPL_NAND_BOOT
3618 Add support NAND boot
3620 CONFIG_SYS_NAND_U_BOOT_OFFS
3621 Location in NAND to read U-Boot from
3623 CONFIG_SYS_NAND_U_BOOT_DST
3624 Location in memory to load U-Boot to
3626 CONFIG_SYS_NAND_U_BOOT_SIZE
3627 Size of image to load
3629 CONFIG_SYS_NAND_U_BOOT_START
3630 Entry point in loaded image to jump to
3632 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3633 Define this if you need to first read the OOB and then the
3634 data. This is used for example on davinci plattforms.
3636 CONFIG_SPL_OMAP3_ID_NAND
3637 Support for an OMAP3-specific set of functions to return the
3638 ID and MFR of the first attached NAND chip, if present.
3640 CONFIG_SPL_SERIAL_SUPPORT
3641 Support for drivers/serial/libserial.o in SPL binary
3643 CONFIG_SPL_SPI_FLASH_SUPPORT
3644 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3646 CONFIG_SPL_SPI_SUPPORT
3647 Support for drivers/spi/libspi.o in SPL binary
3649 CONFIG_SPL_RAM_DEVICE
3650 Support for running image already present in ram, in SPL binary
3652 CONFIG_SPL_LIBGENERIC_SUPPORT
3653 Support for lib/libgeneric.o in SPL binary
3655 CONFIG_SPL_ENV_SUPPORT
3656 Support for the environment operating in SPL binary
3658 CONFIG_SPL_NET_SUPPORT
3659 Support for the net/libnet.o in SPL binary.
3660 It conflicts with SPL env from storage medium specified by
3661 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3664 Image offset to which the SPL should be padded before appending
3665 the SPL payload. By default, this is defined as
3666 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3667 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3668 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3671 Final target image containing SPL and payload. Some SPLs
3672 use an arch-specific makefile fragment instead, for
3673 example if more than one image needs to be produced.
3675 CONFIG_FIT_SPL_PRINT
3676 Printing information about a FIT image adds quite a bit of
3677 code to SPL. So this is normally disabled in SPL. Use this
3678 option to re-enable it. This will affect the output of the
3679 bootm command when booting a FIT image.
3683 Enable building of TPL globally.
3686 Image offset to which the TPL should be padded before appending
3687 the TPL payload. By default, this is defined as
3688 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3689 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3690 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3695 [so far only for SMDK2400 boards]
3697 - Modem support enable:
3698 CONFIG_MODEM_SUPPORT
3700 - RTS/CTS Flow control enable:
3703 - Modem debug support:
3704 CONFIG_MODEM_SUPPORT_DEBUG
3706 Enables debugging stuff (char screen[1024], dbg())
3707 for modem support. Useful only with BDI2000.
3709 - Interrupt support (PPC):
3711 There are common interrupt_init() and timer_interrupt()
3712 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3713 for CPU specific initialization. interrupt_init_cpu()
3714 should set decrementer_count to appropriate value. If
3715 CPU resets decrementer automatically after interrupt
3716 (ppc4xx) it should set decrementer_count to zero.
3717 timer_interrupt() calls timer_interrupt_cpu() for CPU
3718 specific handling. If board has watchdog / status_led
3719 / other_activity_monitor it works automatically from
3720 general timer_interrupt().
3724 In the target system modem support is enabled when a
3725 specific key (key combination) is pressed during
3726 power-on. Otherwise U-Boot will boot normally
3727 (autoboot). The key_pressed() function is called from
3728 board_init(). Currently key_pressed() is a dummy
3729 function, returning 1 and thus enabling modem
3732 If there are no modem init strings in the
3733 environment, U-Boot proceed to autoboot; the
3734 previous output (banner, info printfs) will be
3737 See also: doc/README.Modem
3739 Board initialization settings:
3740 ------------------------------
3742 During Initialization u-boot calls a number of board specific functions
3743 to allow the preparation of board specific prerequisites, e.g. pin setup
3744 before drivers are initialized. To enable these callbacks the
3745 following configuration macros have to be defined. Currently this is
3746 architecture specific, so please check arch/your_architecture/lib/board.c
3747 typically in board_init_f() and board_init_r().
3749 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3750 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3751 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3752 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3754 Configuration Settings:
3755 -----------------------
3757 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3758 Optionally it can be defined to support 64-bit memory commands.
3760 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3761 undefine this when you're short of memory.
3763 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3764 width of the commands listed in the 'help' command output.
3766 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3767 prompt for user input.
3769 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3771 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3773 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3775 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3776 the application (usually a Linux kernel) when it is
3779 - CONFIG_SYS_BAUDRATE_TABLE:
3780 List of legal baudrate settings for this board.
3782 - CONFIG_SYS_CONSOLE_INFO_QUIET
3783 Suppress display of console information at boot.
3785 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3786 If the board specific function
3787 extern int overwrite_console (void);
3788 returns 1, the stdin, stderr and stdout are switched to the
3789 serial port, else the settings in the environment are used.
3791 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3792 Enable the call to overwrite_console().
3794 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3795 Enable overwrite of previous console environment settings.
3797 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3798 Begin and End addresses of the area used by the
3801 - CONFIG_SYS_ALT_MEMTEST:
3802 Enable an alternate, more extensive memory test.
3804 - CONFIG_SYS_MEMTEST_SCRATCH:
3805 Scratch address used by the alternate memory test
3806 You only need to set this if address zero isn't writeable
3808 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3809 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3810 this specified memory area will get subtracted from the top
3811 (end) of RAM and won't get "touched" at all by U-Boot. By
3812 fixing up gd->ram_size the Linux kernel should gets passed
3813 the now "corrected" memory size and won't touch it either.
3814 This should work for arch/ppc and arch/powerpc. Only Linux
3815 board ports in arch/powerpc with bootwrapper support that
3816 recalculate the memory size from the SDRAM controller setup
3817 will have to get fixed in Linux additionally.
3819 This option can be used as a workaround for the 440EPx/GRx
3820 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3823 WARNING: Please make sure that this value is a multiple of
3824 the Linux page size (normally 4k). If this is not the case,
3825 then the end address of the Linux memory will be located at a
3826 non page size aligned address and this could cause major
3829 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3830 Enable temporary baudrate change while serial download
3832 - CONFIG_SYS_SDRAM_BASE:
3833 Physical start address of SDRAM. _Must_ be 0 here.
3835 - CONFIG_SYS_MBIO_BASE:
3836 Physical start address of Motherboard I/O (if using a
3839 - CONFIG_SYS_FLASH_BASE:
3840 Physical start address of Flash memory.
3842 - CONFIG_SYS_MONITOR_BASE:
3843 Physical start address of boot monitor code (set by
3844 make config files to be same as the text base address
3845 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3846 CONFIG_SYS_FLASH_BASE when booting from flash.
3848 - CONFIG_SYS_MONITOR_LEN:
3849 Size of memory reserved for monitor code, used to
3850 determine _at_compile_time_ (!) if the environment is
3851 embedded within the U-Boot image, or in a separate
3854 - CONFIG_SYS_MALLOC_LEN:
3855 Size of DRAM reserved for malloc() use.
3857 - CONFIG_SYS_MALLOC_F_LEN
3858 Size of the malloc() pool for use before relocation. If
3859 this is defined, then a very simple malloc() implementation
3860 will become available before relocation. The address is just
3861 below the global data, and the stack is moved down to make
3864 This feature allocates regions with increasing addresses
3865 within the region. calloc() is supported, but realloc()
3866 is not available. free() is supported but does nothing.
3867 The memory will be freed (or in fact just forgotton) when
3868 U-Boot relocates itself.
3870 Pre-relocation malloc() is only supported on ARM and sandbox
3871 at present but is fairly easy to enable for other archs.
3873 - CONFIG_SYS_BOOTM_LEN:
3874 Normally compressed uImages are limited to an
3875 uncompressed size of 8 MBytes. If this is not enough,
3876 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3877 to adjust this setting to your needs.
3879 - CONFIG_SYS_BOOTMAPSZ:
3880 Maximum size of memory mapped by the startup code of
3881 the Linux kernel; all data that must be processed by
3882 the Linux kernel (bd_info, boot arguments, FDT blob if
3883 used) must be put below this limit, unless "bootm_low"
3884 environment variable is defined and non-zero. In such case
3885 all data for the Linux kernel must be between "bootm_low"
3886 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3887 variable "bootm_mapsize" will override the value of
3888 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3889 then the value in "bootm_size" will be used instead.
3891 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3892 Enable initrd_high functionality. If defined then the
3893 initrd_high feature is enabled and the bootm ramdisk subcommand
3896 - CONFIG_SYS_BOOT_GET_CMDLINE:
3897 Enables allocating and saving kernel cmdline in space between
3898 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3900 - CONFIG_SYS_BOOT_GET_KBD:
3901 Enables allocating and saving a kernel copy of the bd_info in
3902 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3904 - CONFIG_SYS_MAX_FLASH_BANKS:
3905 Max number of Flash memory banks
3907 - CONFIG_SYS_MAX_FLASH_SECT:
3908 Max number of sectors on a Flash chip
3910 - CONFIG_SYS_FLASH_ERASE_TOUT:
3911 Timeout for Flash erase operations (in ms)
3913 - CONFIG_SYS_FLASH_WRITE_TOUT:
3914 Timeout for Flash write operations (in ms)
3916 - CONFIG_SYS_FLASH_LOCK_TOUT
3917 Timeout for Flash set sector lock bit operation (in ms)
3919 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3920 Timeout for Flash clear lock bits operation (in ms)
3922 - CONFIG_SYS_FLASH_PROTECTION
3923 If defined, hardware flash sectors protection is used
3924 instead of U-Boot software protection.
3926 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3928 Enable TFTP transfers directly to flash memory;
3929 without this option such a download has to be
3930 performed in two steps: (1) download to RAM, and (2)
3931 copy from RAM to flash.
3933 The two-step approach is usually more reliable, since
3934 you can check if the download worked before you erase
3935 the flash, but in some situations (when system RAM is
3936 too limited to allow for a temporary copy of the
3937 downloaded image) this option may be very useful.
3939 - CONFIG_SYS_FLASH_CFI:
3940 Define if the flash driver uses extra elements in the
3941 common flash structure for storing flash geometry.
3943 - CONFIG_FLASH_CFI_DRIVER
3944 This option also enables the building of the cfi_flash driver
3945 in the drivers directory
3947 - CONFIG_FLASH_CFI_MTD
3948 This option enables the building of the cfi_mtd driver
3949 in the drivers directory. The driver exports CFI flash
3952 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3953 Use buffered writes to flash.
3955 - CONFIG_FLASH_SPANSION_S29WS_N
3956 s29ws-n MirrorBit flash has non-standard addresses for buffered
3959 - CONFIG_SYS_FLASH_QUIET_TEST
3960 If this option is defined, the common CFI flash doesn't
3961 print it's warning upon not recognized FLASH banks. This
3962 is useful, if some of the configured banks are only
3963 optionally available.
3965 - CONFIG_FLASH_SHOW_PROGRESS
3966 If defined (must be an integer), print out countdown
3967 digits and dots. Recommended value: 45 (9..1) for 80
3968 column displays, 15 (3..1) for 40 column displays.
3970 - CONFIG_FLASH_VERIFY
3971 If defined, the content of the flash (destination) is compared
3972 against the source after the write operation. An error message
3973 will be printed when the contents are not identical.
3974 Please note that this option is useless in nearly all cases,
3975 since such flash programming errors usually are detected earlier
3976 while unprotecting/erasing/programming. Please only enable
3977 this option if you really know what you are doing.
3979 - CONFIG_SYS_RX_ETH_BUFFER:
3980 Defines the number of Ethernet receive buffers. On some
3981 Ethernet controllers it is recommended to set this value
3982 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3983 buffers can be full shortly after enabling the interface
3984 on high Ethernet traffic.
3985 Defaults to 4 if not defined.
3987 - CONFIG_ENV_MAX_ENTRIES
3989 Maximum number of entries in the hash table that is used
3990 internally to store the environment settings. The default
3991 setting is supposed to be generous and should work in most
3992 cases. This setting can be used to tune behaviour; see
3993 lib/hashtable.c for details.
3995 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3996 - CONFIG_ENV_FLAGS_LIST_STATIC
3997 Enable validation of the values given to environment variables when
3998 calling env set. Variables can be restricted to only decimal,
3999 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
4000 the variables can also be restricted to IP address or MAC address.
4002 The format of the list is:
4003 type_attribute = [s|d|x|b|i|m]
4004 access_atribute = [a|r|o|c]
4005 attributes = type_attribute[access_atribute]
4006 entry = variable_name[:attributes]
4009 The type attributes are:
4010 s - String (default)
4013 b - Boolean ([1yYtT|0nNfF])
4017 The access attributes are:
4023 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4024 Define this to a list (string) to define the ".flags"
4025 envirnoment variable in the default or embedded environment.
4027 - CONFIG_ENV_FLAGS_LIST_STATIC
4028 Define this to a list (string) to define validation that
4029 should be done if an entry is not found in the ".flags"
4030 environment variable. To override a setting in the static
4031 list, simply add an entry for the same variable name to the
4034 - CONFIG_ENV_ACCESS_IGNORE_FORCE
4035 If defined, don't allow the -f switch to env set override variable
4038 - CONFIG_SYS_GENERIC_BOARD
4039 This selects the architecture-generic board system instead of the
4040 architecture-specific board files. It is intended to move boards
4041 to this new framework over time. Defining this will disable the
4042 arch/foo/lib/board.c file and use common/board_f.c and
4043 common/board_r.c instead. To use this option your architecture
4044 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
4045 its config.mk file). If you find problems enabling this option on
4046 your board please report the problem and send patches!
4048 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
4049 This is set by OMAP boards for the max time that reset should
4050 be asserted. See doc/README.omap-reset-time for details on how
4051 the value can be calulated on a given board.
4053 The following definitions that deal with the placement and management
4054 of environment data (variable area); in general, we support the
4055 following configurations:
4057 - CONFIG_BUILD_ENVCRC:
4059 Builds up envcrc with the target environment so that external utils
4060 may easily extract it and embed it in final U-Boot images.
4062 - CONFIG_ENV_IS_IN_FLASH:
4064 Define this if the environment is in flash memory.
4066 a) The environment occupies one whole flash sector, which is
4067 "embedded" in the text segment with the U-Boot code. This
4068 happens usually with "bottom boot sector" or "top boot
4069 sector" type flash chips, which have several smaller
4070 sectors at the start or the end. For instance, such a
4071 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4072 such a case you would place the environment in one of the
4073 4 kB sectors - with U-Boot code before and after it. With
4074 "top boot sector" type flash chips, you would put the
4075 environment in one of the last sectors, leaving a gap
4076 between U-Boot and the environment.
4078 - CONFIG_ENV_OFFSET:
4080 Offset of environment data (variable area) to the
4081 beginning of flash memory; for instance, with bottom boot
4082 type flash chips the second sector can be used: the offset
4083 for this sector is given here.
4085 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4089 This is just another way to specify the start address of
4090 the flash sector containing the environment (instead of
4093 - CONFIG_ENV_SECT_SIZE:
4095 Size of the sector containing the environment.
4098 b) Sometimes flash chips have few, equal sized, BIG sectors.
4099 In such a case you don't want to spend a whole sector for
4104 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4105 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4106 of this flash sector for the environment. This saves
4107 memory for the RAM copy of the environment.
4109 It may also save flash memory if you decide to use this
4110 when your environment is "embedded" within U-Boot code,
4111 since then the remainder of the flash sector could be used
4112 for U-Boot code. It should be pointed out that this is
4113 STRONGLY DISCOURAGED from a robustness point of view:
4114 updating the environment in flash makes it always
4115 necessary to erase the WHOLE sector. If something goes
4116 wrong before the contents has been restored from a copy in
4117 RAM, your target system will be dead.
4119 - CONFIG_ENV_ADDR_REDUND
4120 CONFIG_ENV_SIZE_REDUND
4122 These settings describe a second storage area used to hold
4123 a redundant copy of the environment data, so that there is
4124 a valid backup copy in case there is a power failure during
4125 a "saveenv" operation.
4127 BE CAREFUL! Any changes to the flash layout, and some changes to the
4128 source code will make it necessary to adapt <board>/u-boot.lds*
4132 - CONFIG_ENV_IS_IN_NVRAM:
4134 Define this if you have some non-volatile memory device
4135 (NVRAM, battery buffered SRAM) which you want to use for the
4141 These two #defines are used to determine the memory area you
4142 want to use for environment. It is assumed that this memory
4143 can just be read and written to, without any special
4146 BE CAREFUL! The first access to the environment happens quite early
4147 in U-Boot initalization (when we try to get the setting of for the
4148 console baudrate). You *MUST* have mapped your NVRAM area then, or
4151 Please note that even with NVRAM we still use a copy of the
4152 environment in RAM: we could work on NVRAM directly, but we want to
4153 keep settings there always unmodified except somebody uses "saveenv"
4154 to save the current settings.
4157 - CONFIG_ENV_IS_IN_EEPROM:
4159 Use this if you have an EEPROM or similar serial access
4160 device and a driver for it.
4162 - CONFIG_ENV_OFFSET:
4165 These two #defines specify the offset and size of the
4166 environment area within the total memory of your EEPROM.
4168 - CONFIG_SYS_I2C_EEPROM_ADDR:
4169 If defined, specified the chip address of the EEPROM device.
4170 The default address is zero.
4172 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4173 If defined, the number of bits used to address bytes in a
4174 single page in the EEPROM device. A 64 byte page, for example
4175 would require six bits.
4177 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4178 If defined, the number of milliseconds to delay between
4179 page writes. The default is zero milliseconds.
4181 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4182 The length in bytes of the EEPROM memory array address. Note
4183 that this is NOT the chip address length!
4185 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4186 EEPROM chips that implement "address overflow" are ones
4187 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4188 address and the extra bits end up in the "chip address" bit
4189 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4192 Note that we consider the length of the address field to
4193 still be one byte because the extra address bits are hidden
4194 in the chip address.
4196 - CONFIG_SYS_EEPROM_SIZE:
4197 The size in bytes of the EEPROM device.
4199 - CONFIG_ENV_EEPROM_IS_ON_I2C
4200 define this, if you have I2C and SPI activated, and your
4201 EEPROM, which holds the environment, is on the I2C bus.
4203 - CONFIG_I2C_ENV_EEPROM_BUS
4204 if you have an Environment on an EEPROM reached over
4205 I2C muxes, you can define here, how to reach this
4206 EEPROM. For example:
4208 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4210 EEPROM which holds the environment, is reached over
4211 a pca9547 i2c mux with address 0x70, channel 3.
4213 - CONFIG_ENV_IS_IN_DATAFLASH:
4215 Define this if you have a DataFlash memory device which you
4216 want to use for the environment.
4218 - CONFIG_ENV_OFFSET:
4222 These three #defines specify the offset and size of the
4223 environment area within the total memory of your DataFlash placed
4224 at the specified address.
4226 - CONFIG_ENV_IS_IN_SPI_FLASH:
4228 Define this if you have a SPI Flash memory device which you
4229 want to use for the environment.
4231 - CONFIG_ENV_OFFSET:
4234 These two #defines specify the offset and size of the
4235 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4236 aligned to an erase sector boundary.
4238 - CONFIG_ENV_SECT_SIZE:
4240 Define the SPI flash's sector size.
4242 - CONFIG_ENV_OFFSET_REDUND (optional):
4244 This setting describes a second storage area of CONFIG_ENV_SIZE
4245 size used to hold a redundant copy of the environment data, so
4246 that there is a valid backup copy in case there is a power failure
4247 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4248 aligned to an erase sector boundary.
4250 - CONFIG_ENV_SPI_BUS (optional):
4251 - CONFIG_ENV_SPI_CS (optional):
4253 Define the SPI bus and chip select. If not defined they will be 0.
4255 - CONFIG_ENV_SPI_MAX_HZ (optional):
4257 Define the SPI max work clock. If not defined then use 1MHz.
4259 - CONFIG_ENV_SPI_MODE (optional):
4261 Define the SPI work mode. If not defined then use SPI_MODE_3.
4263 - CONFIG_ENV_IS_IN_REMOTE:
4265 Define this if you have a remote memory space which you
4266 want to use for the local device's environment.
4271 These two #defines specify the address and size of the
4272 environment area within the remote memory space. The
4273 local device can get the environment from remote memory
4274 space by SRIO or PCIE links.
4276 BE CAREFUL! For some special cases, the local device can not use
4277 "saveenv" command. For example, the local device will get the
4278 environment stored in a remote NOR flash by SRIO or PCIE link,
4279 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4281 - CONFIG_ENV_IS_IN_NAND:
4283 Define this if you have a NAND device which you want to use
4284 for the environment.
4286 - CONFIG_ENV_OFFSET:
4289 These two #defines specify the offset and size of the environment
4290 area within the first NAND device. CONFIG_ENV_OFFSET must be
4291 aligned to an erase block boundary.
4293 - CONFIG_ENV_OFFSET_REDUND (optional):
4295 This setting describes a second storage area of CONFIG_ENV_SIZE
4296 size used to hold a redundant copy of the environment data, so
4297 that there is a valid backup copy in case there is a power failure
4298 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4299 aligned to an erase block boundary.
4301 - CONFIG_ENV_RANGE (optional):
4303 Specifies the length of the region in which the environment
4304 can be written. This should be a multiple of the NAND device's
4305 block size. Specifying a range with more erase blocks than
4306 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4307 the range to be avoided.
4309 - CONFIG_ENV_OFFSET_OOB (optional):
4311 Enables support for dynamically retrieving the offset of the
4312 environment from block zero's out-of-band data. The
4313 "nand env.oob" command can be used to record this offset.
4314 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4315 using CONFIG_ENV_OFFSET_OOB.
4317 - CONFIG_NAND_ENV_DST
4319 Defines address in RAM to which the nand_spl code should copy the
4320 environment. If redundant environment is used, it will be copied to
4321 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4323 - CONFIG_ENV_IS_IN_UBI:
4325 Define this if you have an UBI volume that you want to use for the
4326 environment. This has the benefit of wear-leveling the environment
4327 accesses, which is important on NAND.
4329 - CONFIG_ENV_UBI_PART:
4331 Define this to a string that is the mtd partition containing the UBI.
4333 - CONFIG_ENV_UBI_VOLUME:
4335 Define this to the name of the volume that you want to store the
4338 - CONFIG_ENV_UBI_VOLUME_REDUND:
4340 Define this to the name of another volume to store a second copy of
4341 the environment in. This will enable redundant environments in UBI.
4342 It is assumed that both volumes are in the same MTD partition.
4344 - CONFIG_UBI_SILENCE_MSG
4345 - CONFIG_UBIFS_SILENCE_MSG
4347 You will probably want to define these to avoid a really noisy system
4348 when storing the env in UBI.
4350 - CONFIG_ENV_IS_IN_FAT:
4351 Define this if you want to use the FAT file system for the environment.
4353 - FAT_ENV_INTERFACE:
4355 Define this to a string that is the name of the block device.
4357 - FAT_ENV_DEV_AND_PART:
4359 Define this to a string to specify the partition of the device. It can
4362 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4363 - "D:P": device D partition P. Error occurs if device D has no
4366 - "D" or "D:": device D partition 1 if device D has partition
4367 table, or the whole device D if has no partition
4369 - "D:auto": first partition in device D with bootable flag set.
4370 If none, first valid paratition in device D. If no
4371 partition table then means device D.
4375 It's a string of the FAT file name. This file use to store the
4379 This should be defined. Otherwise it cannot save the envrionment file.
4381 - CONFIG_ENV_IS_IN_MMC:
4383 Define this if you have an MMC device which you want to use for the
4386 - CONFIG_SYS_MMC_ENV_DEV:
4388 Specifies which MMC device the environment is stored in.
4390 - CONFIG_SYS_MMC_ENV_PART (optional):
4392 Specifies which MMC partition the environment is stored in. If not
4393 set, defaults to partition 0, the user area. Common values might be
4394 1 (first MMC boot partition), 2 (second MMC boot partition).
4396 - CONFIG_ENV_OFFSET:
4399 These two #defines specify the offset and size of the environment
4400 area within the specified MMC device.
4402 If offset is positive (the usual case), it is treated as relative to
4403 the start of the MMC partition. If offset is negative, it is treated
4404 as relative to the end of the MMC partition. This can be useful if
4405 your board may be fitted with different MMC devices, which have
4406 different sizes for the MMC partitions, and you always want the
4407 environment placed at the very end of the partition, to leave the
4408 maximum possible space before it, to store other data.
4410 These two values are in units of bytes, but must be aligned to an
4411 MMC sector boundary.
4413 - CONFIG_ENV_OFFSET_REDUND (optional):
4415 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4416 hold a redundant copy of the environment data. This provides a
4417 valid backup copy in case the other copy is corrupted, e.g. due
4418 to a power failure during a "saveenv" operation.
4420 This value may also be positive or negative; this is handled in the
4421 same way as CONFIG_ENV_OFFSET.
4423 This value is also in units of bytes, but must also be aligned to
4424 an MMC sector boundary.
4426 - CONFIG_ENV_SIZE_REDUND (optional):
4428 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4429 set. If this value is set, it must be set to the same value as
4432 - CONFIG_SYS_SPI_INIT_OFFSET
4434 Defines offset to the initial SPI buffer area in DPRAM. The
4435 area is used at an early stage (ROM part) if the environment
4436 is configured to reside in the SPI EEPROM: We need a 520 byte
4437 scratch DPRAM area. It is used between the two initialization
4438 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4439 to be a good choice since it makes it far enough from the
4440 start of the data area as well as from the stack pointer.
4442 Please note that the environment is read-only until the monitor
4443 has been relocated to RAM and a RAM copy of the environment has been
4444 created; also, when using EEPROM you will have to use getenv_f()
4445 until then to read environment variables.
4447 The environment is protected by a CRC32 checksum. Before the monitor
4448 is relocated into RAM, as a result of a bad CRC you will be working
4449 with the compiled-in default environment - *silently*!!! [This is
4450 necessary, because the first environment variable we need is the
4451 "baudrate" setting for the console - if we have a bad CRC, we don't
4452 have any device yet where we could complain.]
4454 Note: once the monitor has been relocated, then it will complain if
4455 the default environment is used; a new CRC is computed as soon as you
4456 use the "saveenv" command to store a valid environment.
4458 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4459 Echo the inverted Ethernet link state to the fault LED.
4461 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4462 also needs to be defined.
4464 - CONFIG_SYS_FAULT_MII_ADDR:
4465 MII address of the PHY to check for the Ethernet link state.
4467 - CONFIG_NS16550_MIN_FUNCTIONS:
4468 Define this if you desire to only have use of the NS16550_init
4469 and NS16550_putc functions for the serial driver located at
4470 drivers/serial/ns16550.c. This option is useful for saving
4471 space for already greatly restricted images, including but not
4472 limited to NAND_SPL configurations.
4474 - CONFIG_DISPLAY_BOARDINFO
4475 Display information about the board that U-Boot is running on
4476 when U-Boot starts up. The board function checkboard() is called
4479 - CONFIG_DISPLAY_BOARDINFO_LATE
4480 Similar to the previous option, but display this information
4481 later, once stdio is running and output goes to the LCD, if
4484 - CONFIG_BOARD_SIZE_LIMIT:
4485 Maximum size of the U-Boot image. When defined, the
4486 build system checks that the actual size does not
4489 Low Level (hardware related) configuration options:
4490 ---------------------------------------------------
4492 - CONFIG_SYS_CACHELINE_SIZE:
4493 Cache Line Size of the CPU.
4495 - CONFIG_SYS_DEFAULT_IMMR:
4496 Default address of the IMMR after system reset.
4498 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4499 and RPXsuper) to be able to adjust the position of
4500 the IMMR register after a reset.
4502 - CONFIG_SYS_CCSRBAR_DEFAULT:
4503 Default (power-on reset) physical address of CCSR on Freescale
4506 - CONFIG_SYS_CCSRBAR:
4507 Virtual address of CCSR. On a 32-bit build, this is typically
4508 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4510 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4511 for cross-platform code that uses that macro instead.
4513 - CONFIG_SYS_CCSRBAR_PHYS:
4514 Physical address of CCSR. CCSR can be relocated to a new
4515 physical address, if desired. In this case, this macro should
4516 be set to that address. Otherwise, it should be set to the
4517 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4518 is typically relocated on 36-bit builds. It is recommended
4519 that this macro be defined via the _HIGH and _LOW macros:
4521 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4522 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4524 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4525 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4526 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4527 used in assembly code, so it must not contain typecasts or
4528 integer size suffixes (e.g. "ULL").
4530 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4531 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4532 used in assembly code, so it must not contain typecasts or
4533 integer size suffixes (e.g. "ULL").
4535 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4536 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4537 forced to a value that ensures that CCSR is not relocated.
4539 - Floppy Disk Support:
4540 CONFIG_SYS_FDC_DRIVE_NUMBER
4542 the default drive number (default value 0)
4544 CONFIG_SYS_ISA_IO_STRIDE
4546 defines the spacing between FDC chipset registers
4549 CONFIG_SYS_ISA_IO_OFFSET
4551 defines the offset of register from address. It
4552 depends on which part of the data bus is connected to
4553 the FDC chipset. (default value 0)
4555 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4556 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4559 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4560 fdc_hw_init() is called at the beginning of the FDC
4561 setup. fdc_hw_init() must be provided by the board
4562 source code. It is used to make hardware dependant
4566 Most IDE controllers were designed to be connected with PCI
4567 interface. Only few of them were designed for AHB interface.
4568 When software is doing ATA command and data transfer to
4569 IDE devices through IDE-AHB controller, some additional
4570 registers accessing to these kind of IDE-AHB controller
4573 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4574 DO NOT CHANGE unless you know exactly what you're
4575 doing! (11-4) [MPC8xx/82xx systems only]
4577 - CONFIG_SYS_INIT_RAM_ADDR:
4579 Start address of memory area that can be used for
4580 initial data and stack; please note that this must be
4581 writable memory that is working WITHOUT special
4582 initialization, i. e. you CANNOT use normal RAM which
4583 will become available only after programming the
4584 memory controller and running certain initialization
4587 U-Boot uses the following memory types:
4588 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4589 - MPC824X: data cache
4590 - PPC4xx: data cache
4592 - CONFIG_SYS_GBL_DATA_OFFSET:
4594 Offset of the initial data structure in the memory
4595 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4596 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4597 data is located at the end of the available space
4598 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4599 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4600 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4601 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4604 On the MPC824X (or other systems that use the data
4605 cache for initial memory) the address chosen for
4606 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4607 point to an otherwise UNUSED address space between
4608 the top of RAM and the start of the PCI space.
4610 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4612 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4614 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4616 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4618 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4620 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4622 - CONFIG_SYS_OR_TIMING_SDRAM:
4625 - CONFIG_SYS_MAMR_PTA:
4626 periodic timer for refresh
4628 - CONFIG_SYS_DER: Debug Event Register (37-47)
4630 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4631 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4632 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4633 CONFIG_SYS_BR1_PRELIM:
4634 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4636 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4637 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4638 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4639 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4641 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4642 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4643 Machine Mode Register and Memory Periodic Timer
4644 Prescaler definitions (SDRAM timing)
4646 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4647 enable I2C microcode relocation patch (MPC8xx);
4648 define relocation offset in DPRAM [DSP2]
4650 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4651 enable SMC microcode relocation patch (MPC8xx);
4652 define relocation offset in DPRAM [SMC1]
4654 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4655 enable SPI microcode relocation patch (MPC8xx);
4656 define relocation offset in DPRAM [SCC4]
4658 - CONFIG_SYS_USE_OSCCLK:
4659 Use OSCM clock mode on MBX8xx board. Be careful,
4660 wrong setting might damage your board. Read
4661 doc/README.MBX before setting this variable!
4663 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4664 Offset of the bootmode word in DPRAM used by post
4665 (Power On Self Tests). This definition overrides
4666 #define'd default value in commproc.h resp.
4669 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4670 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4671 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4672 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4673 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4674 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4675 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4676 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4677 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4679 - CONFIG_PCI_DISABLE_PCIE:
4680 Disable PCI-Express on systems where it is supported but not
4683 - CONFIG_PCI_ENUM_ONLY
4684 Only scan through and get the devices on the busses.
4685 Don't do any setup work, presumably because someone or
4686 something has already done it, and we don't need to do it
4687 a second time. Useful for platforms that are pre-booted
4688 by coreboot or similar.
4690 - CONFIG_PCI_INDIRECT_BRIDGE:
4691 Enable support for indirect PCI bridges.
4694 Chip has SRIO or not
4697 Board has SRIO 1 port available
4700 Board has SRIO 2 port available
4702 - CONFIG_SRIO_PCIE_BOOT_MASTER
4703 Board can support master function for Boot from SRIO and PCIE
4705 - CONFIG_SYS_SRIOn_MEM_VIRT:
4706 Virtual Address of SRIO port 'n' memory region
4708 - CONFIG_SYS_SRIOn_MEM_PHYS:
4709 Physical Address of SRIO port 'n' memory region
4711 - CONFIG_SYS_SRIOn_MEM_SIZE:
4712 Size of SRIO port 'n' memory region
4714 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4715 Defined to tell the NAND controller that the NAND chip is using
4717 Not all NAND drivers use this symbol.
4718 Example of drivers that use it:
4719 - drivers/mtd/nand/ndfc.c
4720 - drivers/mtd/nand/mxc_nand.c
4722 - CONFIG_SYS_NDFC_EBC0_CFG
4723 Sets the EBC0_CFG register for the NDFC. If not defined
4724 a default value will be used.
4727 Get DDR timing information from an I2C EEPROM. Common
4728 with pluggable memory modules such as SODIMMs
4731 I2C address of the SPD EEPROM
4733 - CONFIG_SYS_SPD_BUS_NUM
4734 If SPD EEPROM is on an I2C bus other than the first
4735 one, specify here. Note that the value must resolve
4736 to something your driver can deal with.
4738 - CONFIG_SYS_DDR_RAW_TIMING
4739 Get DDR timing information from other than SPD. Common with
4740 soldered DDR chips onboard without SPD. DDR raw timing
4741 parameters are extracted from datasheet and hard-coded into
4742 header files or board specific files.
4744 - CONFIG_FSL_DDR_INTERACTIVE
4745 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4747 - CONFIG_SYS_83XX_DDR_USES_CS0
4748 Only for 83xx systems. If specified, then DDR should
4749 be configured using CS0 and CS1 instead of CS2 and CS3.
4751 - CONFIG_ETHER_ON_FEC[12]
4752 Define to enable FEC[12] on a 8xx series processor.
4754 - CONFIG_FEC[12]_PHY
4755 Define to the hardcoded PHY address which corresponds
4756 to the given FEC; i. e.
4757 #define CONFIG_FEC1_PHY 4
4758 means that the PHY with address 4 is connected to FEC1
4760 When set to -1, means to probe for first available.
4762 - CONFIG_FEC[12]_PHY_NORXERR
4763 The PHY does not have a RXERR line (RMII only).
4764 (so program the FEC to ignore it).
4767 Enable RMII mode for all FECs.
4768 Note that this is a global option, we can't
4769 have one FEC in standard MII mode and another in RMII mode.
4771 - CONFIG_CRC32_VERIFY
4772 Add a verify option to the crc32 command.
4775 => crc32 -v <address> <count> <crc32>
4777 Where address/count indicate a memory area
4778 and crc32 is the correct crc32 which the
4782 Add the "loopw" memory command. This only takes effect if
4783 the memory commands are activated globally (CONFIG_CMD_MEM).
4786 Add the "mdc" and "mwc" memory commands. These are cyclic
4791 This command will print 4 bytes (10,11,12,13) each 500 ms.
4793 => mwc.l 100 12345678 10
4794 This command will write 12345678 to address 100 all 10 ms.
4796 This only takes effect if the memory commands are activated
4797 globally (CONFIG_CMD_MEM).
4799 - CONFIG_SKIP_LOWLEVEL_INIT
4800 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4801 low level initializations (like setting up the memory
4802 controller) are omitted and/or U-Boot does not
4803 relocate itself into RAM.
4805 Normally this variable MUST NOT be defined. The only
4806 exception is when U-Boot is loaded (to RAM) by some
4807 other boot loader or by a debugger which performs
4808 these initializations itself.
4811 Modifies the behaviour of start.S when compiling a loader
4812 that is executed before the actual U-Boot. E.g. when
4813 compiling a NAND SPL.
4816 Modifies the behaviour of start.S when compiling a loader
4817 that is executed after the SPL and before the actual U-Boot.
4818 It is loaded by the SPL.
4820 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4821 Only for 85xx systems. If this variable is specified, the section
4822 .resetvec is not kept and the section .bootpg is placed in the
4823 previous 4k of the .text section.
4825 - CONFIG_ARCH_MAP_SYSMEM
4826 Generally U-Boot (and in particular the md command) uses
4827 effective address. It is therefore not necessary to regard
4828 U-Boot address as virtual addresses that need to be translated
4829 to physical addresses. However, sandbox requires this, since
4830 it maintains its own little RAM buffer which contains all
4831 addressable memory. This option causes some memory accesses
4832 to be mapped through map_sysmem() / unmap_sysmem().
4834 - CONFIG_USE_ARCH_MEMCPY
4835 CONFIG_USE_ARCH_MEMSET
4836 If these options are used a optimized version of memcpy/memset will
4837 be used if available. These functions may be faster under some
4838 conditions but may increase the binary size.
4840 - CONFIG_X86_RESET_VECTOR
4841 If defined, the x86 reset vector code is included. This is not
4842 needed when U-Boot is running from Coreboot.
4845 Defines the MPU clock speed (in MHz).
4847 NOTE : currently only supported on AM335x platforms.
4849 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4850 Enables the RTC32K OSC on AM33xx based plattforms
4852 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4853 Option to disable subpage write in NAND driver
4854 driver that uses this:
4855 drivers/mtd/nand/davinci_nand.c
4857 Freescale QE/FMAN Firmware Support:
4858 -----------------------------------
4860 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4861 loading of "firmware", which is encoded in the QE firmware binary format.
4862 This firmware often needs to be loaded during U-Boot booting, so macros
4863 are used to identify the storage device (NOR flash, SPI, etc) and the address
4866 - CONFIG_SYS_FMAN_FW_ADDR
4867 The address in the storage device where the FMAN microcode is located. The
4868 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4871 - CONFIG_SYS_QE_FW_ADDR
4872 The address in the storage device where the QE microcode is located. The
4873 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4876 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4877 The maximum possible size of the firmware. The firmware binary format
4878 has a field that specifies the actual size of the firmware, but it
4879 might not be possible to read any part of the firmware unless some
4880 local storage is allocated to hold the entire firmware first.
4882 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4883 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4884 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4885 virtual address in NOR flash.
4887 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4888 Specifies that QE/FMAN firmware is located in NAND flash.
4889 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4891 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4892 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4893 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4895 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4896 Specifies that QE/FMAN firmware is located on the primary SPI
4897 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4899 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4900 Specifies that QE/FMAN firmware is located in the remote (master)
4901 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4902 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4903 window->master inbound window->master LAW->the ucode address in
4904 master's memory space.
4906 Freescale Layerscape Management Complex Firmware Support:
4907 ---------------------------------------------------------
4908 The Freescale Layerscape Management Complex (MC) supports the loading of
4910 This firmware often needs to be loaded during U-Boot booting, so macros
4911 are used to identify the storage device (NOR flash, SPI, etc) and the address
4914 - CONFIG_FSL_MC_ENET
4915 Enable the MC driver for Layerscape SoCs.
4917 - CONFIG_SYS_LS_MC_FW_ADDR
4918 The address in the storage device where the firmware is located. The
4919 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
4922 - CONFIG_SYS_LS_MC_FW_LENGTH
4923 The maximum possible size of the firmware. The firmware binary format
4924 has a field that specifies the actual size of the firmware, but it
4925 might not be possible to read any part of the firmware unless some
4926 local storage is allocated to hold the entire firmware first.
4928 - CONFIG_SYS_LS_MC_FW_IN_NOR
4929 Specifies that MC firmware is located in NOR flash, mapped as
4930 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
4931 virtual address in NOR flash.
4933 Building the Software:
4934 ======================
4936 Building U-Boot has been tested in several native build environments
4937 and in many different cross environments. Of course we cannot support
4938 all possibly existing versions of cross development tools in all
4939 (potentially obsolete) versions. In case of tool chain problems we
4940 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4941 which is extensively used to build and test U-Boot.
4943 If you are not using a native environment, it is assumed that you
4944 have GNU cross compiling tools available in your path. In this case,
4945 you must set the environment variable CROSS_COMPILE in your shell.
4946 Note that no changes to the Makefile or any other source files are
4947 necessary. For example using the ELDK on a 4xx CPU, please enter:
4949 $ CROSS_COMPILE=ppc_4xx-
4950 $ export CROSS_COMPILE
4952 Note: If you wish to generate Windows versions of the utilities in
4953 the tools directory you can use the MinGW toolchain
4954 (http://www.mingw.org). Set your HOST tools to the MinGW
4955 toolchain and execute 'make tools'. For example:
4957 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4959 Binaries such as tools/mkimage.exe will be created which can
4960 be executed on computers running Windows.
4962 U-Boot is intended to be simple to build. After installing the
4963 sources you must configure U-Boot for one specific board type. This
4968 where "NAME_defconfig" is the name of one of the existing configu-
4969 rations; see boards.cfg for supported names.
4971 Note: for some board special configuration names may exist; check if
4972 additional information is available from the board vendor; for
4973 instance, the TQM823L systems are available without (standard)
4974 or with LCD support. You can select such additional "features"
4975 when choosing the configuration, i. e.
4977 make TQM823L_defconfig
4978 - will configure for a plain TQM823L, i. e. no LCD support
4980 make TQM823L_LCD_defconfig
4981 - will configure for a TQM823L with U-Boot console on LCD
4986 Finally, type "make all", and you should get some working U-Boot
4987 images ready for download to / installation on your system:
4989 - "u-boot.bin" is a raw binary image
4990 - "u-boot" is an image in ELF binary format
4991 - "u-boot.srec" is in Motorola S-Record format
4993 By default the build is performed locally and the objects are saved
4994 in the source directory. One of the two methods can be used to change
4995 this behavior and build U-Boot to some external directory:
4997 1. Add O= to the make command line invocations:
4999 make O=/tmp/build distclean
5000 make O=/tmp/build NAME_defconfig
5001 make O=/tmp/build all
5003 2. Set environment variable BUILD_DIR to point to the desired location:
5005 export BUILD_DIR=/tmp/build
5010 Note that the command line "O=" setting overrides the BUILD_DIR environment
5014 Please be aware that the Makefiles assume you are using GNU make, so
5015 for instance on NetBSD you might need to use "gmake" instead of
5019 If the system board that you have is not listed, then you will need
5020 to port U-Boot to your hardware platform. To do this, follow these
5023 1. Add a new configuration option for your board to the toplevel
5024 "boards.cfg" file, using the existing entries as examples.
5025 Follow the instructions there to keep the boards in order.
5026 2. Create a new directory to hold your board specific code. Add any
5027 files you need. In your board directory, you will need at least
5028 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
5029 3. Create a new configuration file "include/configs/<board>.h" for
5031 3. If you're porting U-Boot to a new CPU, then also create a new
5032 directory to hold your CPU specific code. Add any files you need.
5033 4. Run "make <board>_defconfig" with your new name.
5034 5. Type "make", and you should get a working "u-boot.srec" file
5035 to be installed on your target system.
5036 6. Debug and solve any problems that might arise.
5037 [Of course, this last step is much harder than it sounds.]
5040 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5041 ==============================================================
5043 If you have modified U-Boot sources (for instance added a new board
5044 or support for new devices, a new CPU, etc.) you are expected to
5045 provide feedback to the other developers. The feedback normally takes
5046 the form of a "patch", i. e. a context diff against a certain (latest
5047 official or latest in the git repository) version of U-Boot sources.
5049 But before you submit such a patch, please verify that your modifi-
5050 cation did not break existing code. At least make sure that *ALL* of
5051 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5052 just run the "MAKEALL" script, which will configure and build U-Boot
5053 for ALL supported system. Be warned, this will take a while. You can
5054 select which (cross) compiler to use by passing a `CROSS_COMPILE'
5055 environment variable to the script, i. e. to use the ELDK cross tools
5058 CROSS_COMPILE=ppc_8xx- MAKEALL
5060 or to build on a native PowerPC system you can type
5062 CROSS_COMPILE=' ' MAKEALL
5064 When using the MAKEALL script, the default behaviour is to build
5065 U-Boot in the source directory. This location can be changed by
5066 setting the BUILD_DIR environment variable. Also, for each target
5067 built, the MAKEALL script saves two log files (<target>.ERR and
5068 <target>.MAKEALL) in the <source dir>/LOG directory. This default
5069 location can be changed by setting the MAKEALL_LOGDIR environment
5070 variable. For example:
5072 export BUILD_DIR=/tmp/build
5073 export MAKEALL_LOGDIR=/tmp/log
5074 CROSS_COMPILE=ppc_8xx- MAKEALL
5076 With the above settings build objects are saved in the /tmp/build,
5077 log files are saved in the /tmp/log and the source tree remains clean
5078 during the whole build process.
5081 See also "U-Boot Porting Guide" below.
5084 Monitor Commands - Overview:
5085 ============================
5087 go - start application at address 'addr'
5088 run - run commands in an environment variable
5089 bootm - boot application image from memory
5090 bootp - boot image via network using BootP/TFTP protocol
5091 bootz - boot zImage from memory
5092 tftpboot- boot image via network using TFTP protocol
5093 and env variables "ipaddr" and "serverip"
5094 (and eventually "gatewayip")
5095 tftpput - upload a file via network using TFTP protocol
5096 rarpboot- boot image via network using RARP/TFTP protocol
5097 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5098 loads - load S-Record file over serial line
5099 loadb - load binary file over serial line (kermit mode)
5101 mm - memory modify (auto-incrementing)
5102 nm - memory modify (constant address)
5103 mw - memory write (fill)
5105 cmp - memory compare
5106 crc32 - checksum calculation
5107 i2c - I2C sub-system
5108 sspi - SPI utility commands
5109 base - print or set address offset
5110 printenv- print environment variables
5111 setenv - set environment variables
5112 saveenv - save environment variables to persistent storage
5113 protect - enable or disable FLASH write protection
5114 erase - erase FLASH memory
5115 flinfo - print FLASH memory information
5116 nand - NAND memory operations (see doc/README.nand)
5117 bdinfo - print Board Info structure
5118 iminfo - print header information for application image
5119 coninfo - print console devices and informations
5120 ide - IDE sub-system
5121 loop - infinite loop on address range
5122 loopw - infinite write loop on address range
5123 mtest - simple RAM test
5124 icache - enable or disable instruction cache
5125 dcache - enable or disable data cache
5126 reset - Perform RESET of the CPU
5127 echo - echo args to console
5128 version - print monitor version
5129 help - print online help
5130 ? - alias for 'help'
5133 Monitor Commands - Detailed Description:
5134 ========================================
5138 For now: just type "help <command>".
5141 Environment Variables:
5142 ======================
5144 U-Boot supports user configuration using Environment Variables which
5145 can be made persistent by saving to Flash memory.
5147 Environment Variables are set using "setenv", printed using
5148 "printenv", and saved to Flash using "saveenv". Using "setenv"
5149 without a value can be used to delete a variable from the
5150 environment. As long as you don't save the environment you are
5151 working with an in-memory copy. In case the Flash area containing the
5152 environment is erased by accident, a default environment is provided.
5154 Some configuration options can be set using Environment Variables.
5156 List of environment variables (most likely not complete):
5158 baudrate - see CONFIG_BAUDRATE
5160 bootdelay - see CONFIG_BOOTDELAY
5162 bootcmd - see CONFIG_BOOTCOMMAND
5164 bootargs - Boot arguments when booting an RTOS image
5166 bootfile - Name of the image to load with TFTP
5168 bootm_low - Memory range available for image processing in the bootm
5169 command can be restricted. This variable is given as
5170 a hexadecimal number and defines lowest address allowed
5171 for use by the bootm command. See also "bootm_size"
5172 environment variable. Address defined by "bootm_low" is
5173 also the base of the initial memory mapping for the Linux
5174 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5177 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5178 This variable is given as a hexadecimal number and it
5179 defines the size of the memory region starting at base
5180 address bootm_low that is accessible by the Linux kernel
5181 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5182 as the default value if it is defined, and bootm_size is
5185 bootm_size - Memory range available for image processing in the bootm
5186 command can be restricted. This variable is given as
5187 a hexadecimal number and defines the size of the region
5188 allowed for use by the bootm command. See also "bootm_low"
5189 environment variable.
5191 updatefile - Location of the software update file on a TFTP server, used
5192 by the automatic software update feature. Please refer to
5193 documentation in doc/README.update for more details.
5195 autoload - if set to "no" (any string beginning with 'n'),
5196 "bootp" will just load perform a lookup of the
5197 configuration from the BOOTP server, but not try to
5198 load any image using TFTP
5200 autostart - if set to "yes", an image loaded using the "bootp",
5201 "rarpboot", "tftpboot" or "diskboot" commands will
5202 be automatically started (by internally calling
5205 If set to "no", a standalone image passed to the
5206 "bootm" command will be copied to the load address
5207 (and eventually uncompressed), but NOT be started.
5208 This can be used to load and uncompress arbitrary
5211 fdt_high - if set this restricts the maximum address that the
5212 flattened device tree will be copied into upon boot.
5213 For example, if you have a system with 1 GB memory
5214 at physical address 0x10000000, while Linux kernel
5215 only recognizes the first 704 MB as low memory, you
5216 may need to set fdt_high as 0x3C000000 to have the
5217 device tree blob be copied to the maximum address
5218 of the 704 MB low memory, so that Linux kernel can
5219 access it during the boot procedure.
5221 If this is set to the special value 0xFFFFFFFF then
5222 the fdt will not be copied at all on boot. For this
5223 to work it must reside in writable memory, have
5224 sufficient padding on the end of it for u-boot to
5225 add the information it needs into it, and the memory
5226 must be accessible by the kernel.
5228 fdtcontroladdr- if set this is the address of the control flattened
5229 device tree used by U-Boot when CONFIG_OF_CONTROL is
5232 i2cfast - (PPC405GP|PPC405EP only)
5233 if set to 'y' configures Linux I2C driver for fast
5234 mode (400kHZ). This environment variable is used in
5235 initialization code. So, for changes to be effective
5236 it must be saved and board must be reset.
5238 initrd_high - restrict positioning of initrd images:
5239 If this variable is not set, initrd images will be
5240 copied to the highest possible address in RAM; this
5241 is usually what you want since it allows for
5242 maximum initrd size. If for some reason you want to
5243 make sure that the initrd image is loaded below the
5244 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5245 variable to a value of "no" or "off" or "0".
5246 Alternatively, you can set it to a maximum upper
5247 address to use (U-Boot will still check that it
5248 does not overwrite the U-Boot stack and data).
5250 For instance, when you have a system with 16 MB
5251 RAM, and want to reserve 4 MB from use by Linux,
5252 you can do this by adding "mem=12M" to the value of
5253 the "bootargs" variable. However, now you must make
5254 sure that the initrd image is placed in the first
5255 12 MB as well - this can be done with
5257 setenv initrd_high 00c00000
5259 If you set initrd_high to 0xFFFFFFFF, this is an
5260 indication to U-Boot that all addresses are legal
5261 for the Linux kernel, including addresses in flash
5262 memory. In this case U-Boot will NOT COPY the
5263 ramdisk at all. This may be useful to reduce the
5264 boot time on your system, but requires that this
5265 feature is supported by your Linux kernel.
5267 ipaddr - IP address; needed for tftpboot command
5269 loadaddr - Default load address for commands like "bootp",
5270 "rarpboot", "tftpboot", "loadb" or "diskboot"
5272 loads_echo - see CONFIG_LOADS_ECHO
5274 serverip - TFTP server IP address; needed for tftpboot command
5276 bootretry - see CONFIG_BOOT_RETRY_TIME
5278 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5280 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5282 ethprime - controls which interface is used first.
5284 ethact - controls which interface is currently active.
5285 For example you can do the following
5287 => setenv ethact FEC
5288 => ping 192.168.0.1 # traffic sent on FEC
5289 => setenv ethact SCC
5290 => ping 10.0.0.1 # traffic sent on SCC
5292 ethrotate - When set to "no" U-Boot does not go through all
5293 available network interfaces.
5294 It just stays at the currently selected interface.
5296 netretry - When set to "no" each network operation will
5297 either succeed or fail without retrying.
5298 When set to "once" the network operation will
5299 fail when all the available network interfaces
5300 are tried once without success.
5301 Useful on scripts which control the retry operation
5304 npe_ucode - set load address for the NPE microcode
5306 silent_linux - If set then linux will be told to boot silently, by
5307 changing the console to be empty. If "yes" it will be
5308 made silent. If "no" it will not be made silent. If
5309 unset, then it will be made silent if the U-Boot console
5312 tftpsrcport - If this is set, the value is used for TFTP's
5315 tftpdstport - If this is set, the value is used for TFTP's UDP
5316 destination port instead of the Well Know Port 69.
5318 tftpblocksize - Block size to use for TFTP transfers; if not set,
5319 we use the TFTP server's default block size
5321 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5322 seconds, minimum value is 1000 = 1 second). Defines
5323 when a packet is considered to be lost so it has to
5324 be retransmitted. The default is 5000 = 5 seconds.
5325 Lowering this value may make downloads succeed
5326 faster in networks with high packet loss rates or
5327 with unreliable TFTP servers.
5329 vlan - When set to a value < 4095 the traffic over
5330 Ethernet is encapsulated/received over 802.1q
5333 The following image location variables contain the location of images
5334 used in booting. The "Image" column gives the role of the image and is
5335 not an environment variable name. The other columns are environment
5336 variable names. "File Name" gives the name of the file on a TFTP
5337 server, "RAM Address" gives the location in RAM the image will be
5338 loaded to, and "Flash Location" gives the image's address in NOR
5339 flash or offset in NAND flash.
5341 *Note* - these variables don't have to be defined for all boards, some
5342 boards currenlty use other variables for these purposes, and some
5343 boards use these variables for other purposes.
5345 Image File Name RAM Address Flash Location
5346 ----- --------- ----------- --------------
5347 u-boot u-boot u-boot_addr_r u-boot_addr
5348 Linux kernel bootfile kernel_addr_r kernel_addr
5349 device tree blob fdtfile fdt_addr_r fdt_addr
5350 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5352 The following environment variables may be used and automatically
5353 updated by the network boot commands ("bootp" and "rarpboot"),
5354 depending the information provided by your boot server:
5356 bootfile - see above
5357 dnsip - IP address of your Domain Name Server
5358 dnsip2 - IP address of your secondary Domain Name Server
5359 gatewayip - IP address of the Gateway (Router) to use
5360 hostname - Target hostname
5362 netmask - Subnet Mask
5363 rootpath - Pathname of the root filesystem on the NFS server
5364 serverip - see above
5367 There are two special Environment Variables:
5369 serial# - contains hardware identification information such
5370 as type string and/or serial number
5371 ethaddr - Ethernet address
5373 These variables can be set only once (usually during manufacturing of
5374 the board). U-Boot refuses to delete or overwrite these variables
5375 once they have been set once.
5378 Further special Environment Variables:
5380 ver - Contains the U-Boot version string as printed
5381 with the "version" command. This variable is
5382 readonly (see CONFIG_VERSION_VARIABLE).
5385 Please note that changes to some configuration parameters may take
5386 only effect after the next boot (yes, that's just like Windoze :-).
5389 Callback functions for environment variables:
5390 ---------------------------------------------
5392 For some environment variables, the behavior of u-boot needs to change
5393 when their values are changed. This functionailty allows functions to
5394 be associated with arbitrary variables. On creation, overwrite, or
5395 deletion, the callback will provide the opportunity for some side
5396 effect to happen or for the change to be rejected.
5398 The callbacks are named and associated with a function using the
5399 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5401 These callbacks are associated with variables in one of two ways. The
5402 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5403 in the board configuration to a string that defines a list of
5404 associations. The list must be in the following format:
5406 entry = variable_name[:callback_name]
5409 If the callback name is not specified, then the callback is deleted.
5410 Spaces are also allowed anywhere in the list.
5412 Callbacks can also be associated by defining the ".callbacks" variable
5413 with the same list format above. Any association in ".callbacks" will
5414 override any association in the static list. You can define
5415 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5416 ".callbacks" envirnoment variable in the default or embedded environment.
5419 Command Line Parsing:
5420 =====================
5422 There are two different command line parsers available with U-Boot:
5423 the old "simple" one, and the much more powerful "hush" shell:
5425 Old, simple command line parser:
5426 --------------------------------
5428 - supports environment variables (through setenv / saveenv commands)
5429 - several commands on one line, separated by ';'
5430 - variable substitution using "... ${name} ..." syntax
5431 - special characters ('$', ';') can be escaped by prefixing with '\',
5433 setenv bootcmd bootm \${address}
5434 - You can also escape text by enclosing in single apostrophes, for example:
5435 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5440 - similar to Bourne shell, with control structures like
5441 if...then...else...fi, for...do...done; while...do...done,
5442 until...do...done, ...
5443 - supports environment ("global") variables (through setenv / saveenv
5444 commands) and local shell variables (through standard shell syntax
5445 "name=value"); only environment variables can be used with "run"
5451 (1) If a command line (or an environment variable executed by a "run"
5452 command) contains several commands separated by semicolon, and
5453 one of these commands fails, then the remaining commands will be
5456 (2) If you execute several variables with one call to run (i. e.
5457 calling run with a list of variables as arguments), any failing
5458 command will cause "run" to terminate, i. e. the remaining
5459 variables are not executed.
5461 Note for Redundant Ethernet Interfaces:
5462 =======================================
5464 Some boards come with redundant Ethernet interfaces; U-Boot supports
5465 such configurations and is capable of automatic selection of a
5466 "working" interface when needed. MAC assignment works as follows:
5468 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5469 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5470 "eth1addr" (=>eth1), "eth2addr", ...
5472 If the network interface stores some valid MAC address (for instance
5473 in SROM), this is used as default address if there is NO correspon-
5474 ding setting in the environment; if the corresponding environment
5475 variable is set, this overrides the settings in the card; that means:
5477 o If the SROM has a valid MAC address, and there is no address in the
5478 environment, the SROM's address is used.
5480 o If there is no valid address in the SROM, and a definition in the
5481 environment exists, then the value from the environment variable is
5484 o If both the SROM and the environment contain a MAC address, and
5485 both addresses are the same, this MAC address is used.
5487 o If both the SROM and the environment contain a MAC address, and the
5488 addresses differ, the value from the environment is used and a
5491 o If neither SROM nor the environment contain a MAC address, an error
5494 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5495 will be programmed into hardware as part of the initialization process. This
5496 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5497 The naming convention is as follows:
5498 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5503 U-Boot is capable of booting (and performing other auxiliary operations on)
5504 images in two formats:
5506 New uImage format (FIT)
5507 -----------------------
5509 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5510 to Flattened Device Tree). It allows the use of images with multiple
5511 components (several kernels, ramdisks, etc.), with contents protected by
5512 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5518 Old image format is based on binary files which can be basically anything,
5519 preceded by a special header; see the definitions in include/image.h for
5520 details; basically, the header defines the following image properties:
5522 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5523 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5524 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5525 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5527 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5528 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5529 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5530 * Compression Type (uncompressed, gzip, bzip2)
5536 The header is marked by a special Magic Number, and both the header
5537 and the data portions of the image are secured against corruption by
5544 Although U-Boot should support any OS or standalone application
5545 easily, the main focus has always been on Linux during the design of
5548 U-Boot includes many features that so far have been part of some
5549 special "boot loader" code within the Linux kernel. Also, any
5550 "initrd" images to be used are no longer part of one big Linux image;
5551 instead, kernel and "initrd" are separate images. This implementation
5552 serves several purposes:
5554 - the same features can be used for other OS or standalone
5555 applications (for instance: using compressed images to reduce the
5556 Flash memory footprint)
5558 - it becomes much easier to port new Linux kernel versions because
5559 lots of low-level, hardware dependent stuff are done by U-Boot
5561 - the same Linux kernel image can now be used with different "initrd"
5562 images; of course this also means that different kernel images can
5563 be run with the same "initrd". This makes testing easier (you don't
5564 have to build a new "zImage.initrd" Linux image when you just
5565 change a file in your "initrd"). Also, a field-upgrade of the
5566 software is easier now.
5572 Porting Linux to U-Boot based systems:
5573 ---------------------------------------
5575 U-Boot cannot save you from doing all the necessary modifications to
5576 configure the Linux device drivers for use with your target hardware
5577 (no, we don't intend to provide a full virtual machine interface to
5580 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5582 Just make sure your machine specific header file (for instance
5583 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5584 Information structure as we define in include/asm-<arch>/u-boot.h,
5585 and make sure that your definition of IMAP_ADDR uses the same value
5586 as your U-Boot configuration in CONFIG_SYS_IMMR.
5588 Note that U-Boot now has a driver model, a unified model for drivers.
5589 If you are adding a new driver, plumb it into driver model. If there
5590 is no uclass available, you are encouraged to create one. See
5594 Configuring the Linux kernel:
5595 -----------------------------
5597 No specific requirements for U-Boot. Make sure you have some root
5598 device (initial ramdisk, NFS) for your target system.
5601 Building a Linux Image:
5602 -----------------------
5604 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5605 not used. If you use recent kernel source, a new build target
5606 "uImage" will exist which automatically builds an image usable by
5607 U-Boot. Most older kernels also have support for a "pImage" target,
5608 which was introduced for our predecessor project PPCBoot and uses a
5609 100% compatible format.
5613 make TQM850L_defconfig
5618 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5619 encapsulate a compressed Linux kernel image with header information,
5620 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5622 * build a standard "vmlinux" kernel image (in ELF binary format):
5624 * convert the kernel into a raw binary image:
5626 ${CROSS_COMPILE}-objcopy -O binary \
5627 -R .note -R .comment \
5628 -S vmlinux linux.bin
5630 * compress the binary image:
5634 * package compressed binary image for U-Boot:
5636 mkimage -A ppc -O linux -T kernel -C gzip \
5637 -a 0 -e 0 -n "Linux Kernel Image" \
5638 -d linux.bin.gz uImage
5641 The "mkimage" tool can also be used to create ramdisk images for use
5642 with U-Boot, either separated from the Linux kernel image, or
5643 combined into one file. "mkimage" encapsulates the images with a 64
5644 byte header containing information about target architecture,
5645 operating system, image type, compression method, entry points, time
5646 stamp, CRC32 checksums, etc.
5648 "mkimage" can be called in two ways: to verify existing images and
5649 print the header information, or to build new images.
5651 In the first form (with "-l" option) mkimage lists the information
5652 contained in the header of an existing U-Boot image; this includes
5653 checksum verification:
5655 tools/mkimage -l image
5656 -l ==> list image header information
5658 The second form (with "-d" option) is used to build a U-Boot image
5659 from a "data file" which is used as image payload:
5661 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5662 -n name -d data_file image
5663 -A ==> set architecture to 'arch'
5664 -O ==> set operating system to 'os'
5665 -T ==> set image type to 'type'
5666 -C ==> set compression type 'comp'
5667 -a ==> set load address to 'addr' (hex)
5668 -e ==> set entry point to 'ep' (hex)
5669 -n ==> set image name to 'name'
5670 -d ==> use image data from 'datafile'
5672 Right now, all Linux kernels for PowerPC systems use the same load
5673 address (0x00000000), but the entry point address depends on the
5676 - 2.2.x kernels have the entry point at 0x0000000C,
5677 - 2.3.x and later kernels have the entry point at 0x00000000.
5679 So a typical call to build a U-Boot image would read:
5681 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5682 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5683 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5684 > examples/uImage.TQM850L
5685 Image Name: 2.4.4 kernel for TQM850L
5686 Created: Wed Jul 19 02:34:59 2000
5687 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5688 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5689 Load Address: 0x00000000
5690 Entry Point: 0x00000000
5692 To verify the contents of the image (or check for corruption):
5694 -> tools/mkimage -l examples/uImage.TQM850L
5695 Image Name: 2.4.4 kernel for TQM850L
5696 Created: Wed Jul 19 02:34:59 2000
5697 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5698 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5699 Load Address: 0x00000000
5700 Entry Point: 0x00000000
5702 NOTE: for embedded systems where boot time is critical you can trade
5703 speed for memory and install an UNCOMPRESSED image instead: this
5704 needs more space in Flash, but boots much faster since it does not
5705 need to be uncompressed:
5707 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5708 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5709 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5710 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5711 > examples/uImage.TQM850L-uncompressed
5712 Image Name: 2.4.4 kernel for TQM850L
5713 Created: Wed Jul 19 02:34:59 2000
5714 Image Type: PowerPC Linux Kernel Image (uncompressed)
5715 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5716 Load Address: 0x00000000
5717 Entry Point: 0x00000000
5720 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5721 when your kernel is intended to use an initial ramdisk:
5723 -> tools/mkimage -n 'Simple Ramdisk Image' \
5724 > -A ppc -O linux -T ramdisk -C gzip \
5725 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5726 Image Name: Simple Ramdisk Image
5727 Created: Wed Jan 12 14:01:50 2000
5728 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5729 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5730 Load Address: 0x00000000
5731 Entry Point: 0x00000000
5733 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5734 option performs the converse operation of the mkimage's second form (the "-d"
5735 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5738 tools/dumpimage -i image -p position data_file
5739 -i ==> extract from the 'image' a specific 'data_file', \
5740 indexed by 'position'
5743 Installing a Linux Image:
5744 -------------------------
5746 To downloading a U-Boot image over the serial (console) interface,
5747 you must convert the image to S-Record format:
5749 objcopy -I binary -O srec examples/image examples/image.srec
5751 The 'objcopy' does not understand the information in the U-Boot
5752 image header, so the resulting S-Record file will be relative to
5753 address 0x00000000. To load it to a given address, you need to
5754 specify the target address as 'offset' parameter with the 'loads'
5757 Example: install the image to address 0x40100000 (which on the
5758 TQM8xxL is in the first Flash bank):
5760 => erase 40100000 401FFFFF
5766 ## Ready for S-Record download ...
5767 ~>examples/image.srec
5768 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5770 15989 15990 15991 15992
5771 [file transfer complete]
5773 ## Start Addr = 0x00000000
5776 You can check the success of the download using the 'iminfo' command;
5777 this includes a checksum verification so you can be sure no data
5778 corruption happened:
5782 ## Checking Image at 40100000 ...
5783 Image Name: 2.2.13 for initrd on TQM850L
5784 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5785 Data Size: 335725 Bytes = 327 kB = 0 MB
5786 Load Address: 00000000
5787 Entry Point: 0000000c
5788 Verifying Checksum ... OK
5794 The "bootm" command is used to boot an application that is stored in
5795 memory (RAM or Flash). In case of a Linux kernel image, the contents
5796 of the "bootargs" environment variable is passed to the kernel as
5797 parameters. You can check and modify this variable using the
5798 "printenv" and "setenv" commands:
5801 => printenv bootargs
5802 bootargs=root=/dev/ram
5804 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5806 => printenv bootargs
5807 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5810 ## Booting Linux kernel at 40020000 ...
5811 Image Name: 2.2.13 for NFS on TQM850L
5812 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5813 Data Size: 381681 Bytes = 372 kB = 0 MB
5814 Load Address: 00000000
5815 Entry Point: 0000000c
5816 Verifying Checksum ... OK
5817 Uncompressing Kernel Image ... OK
5818 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
5819 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5820 time_init: decrementer frequency = 187500000/60
5821 Calibrating delay loop... 49.77 BogoMIPS
5822 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5825 If you want to boot a Linux kernel with initial RAM disk, you pass
5826 the memory addresses of both the kernel and the initrd image (PPBCOOT
5827 format!) to the "bootm" command:
5829 => imi 40100000 40200000
5831 ## Checking Image at 40100000 ...
5832 Image Name: 2.2.13 for initrd on TQM850L
5833 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5834 Data Size: 335725 Bytes = 327 kB = 0 MB
5835 Load Address: 00000000
5836 Entry Point: 0000000c
5837 Verifying Checksum ... OK
5839 ## Checking Image at 40200000 ...
5840 Image Name: Simple Ramdisk Image
5841 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5842 Data Size: 566530 Bytes = 553 kB = 0 MB
5843 Load Address: 00000000
5844 Entry Point: 00000000
5845 Verifying Checksum ... OK
5847 => bootm 40100000 40200000
5848 ## Booting Linux kernel at 40100000 ...
5849 Image Name: 2.2.13 for initrd on TQM850L
5850 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5851 Data Size: 335725 Bytes = 327 kB = 0 MB
5852 Load Address: 00000000
5853 Entry Point: 0000000c
5854 Verifying Checksum ... OK
5855 Uncompressing Kernel Image ... OK
5856 ## Loading RAMDisk Image at 40200000 ...
5857 Image Name: Simple Ramdisk Image
5858 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5859 Data Size: 566530 Bytes = 553 kB = 0 MB
5860 Load Address: 00000000
5861 Entry Point: 00000000
5862 Verifying Checksum ... OK
5863 Loading Ramdisk ... OK
5864 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
5865 Boot arguments: root=/dev/ram
5866 time_init: decrementer frequency = 187500000/60
5867 Calibrating delay loop... 49.77 BogoMIPS
5869 RAMDISK: Compressed image found at block 0
5870 VFS: Mounted root (ext2 filesystem).
5874 Boot Linux and pass a flat device tree:
5877 First, U-Boot must be compiled with the appropriate defines. See the section
5878 titled "Linux Kernel Interface" above for a more in depth explanation. The
5879 following is an example of how to start a kernel and pass an updated
5885 oft=oftrees/mpc8540ads.dtb
5886 => tftp $oftaddr $oft
5887 Speed: 1000, full duplex
5889 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5890 Filename 'oftrees/mpc8540ads.dtb'.
5891 Load address: 0x300000
5894 Bytes transferred = 4106 (100a hex)
5895 => tftp $loadaddr $bootfile
5896 Speed: 1000, full duplex
5898 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5900 Load address: 0x200000
5901 Loading:############
5903 Bytes transferred = 1029407 (fb51f hex)
5908 => bootm $loadaddr - $oftaddr
5909 ## Booting image at 00200000 ...
5910 Image Name: Linux-2.6.17-dirty
5911 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5912 Data Size: 1029343 Bytes = 1005.2 kB
5913 Load Address: 00000000
5914 Entry Point: 00000000
5915 Verifying Checksum ... OK
5916 Uncompressing Kernel Image ... OK
5917 Booting using flat device tree at 0x300000
5918 Using MPC85xx ADS machine description
5919 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5923 More About U-Boot Image Types:
5924 ------------------------------
5926 U-Boot supports the following image types:
5928 "Standalone Programs" are directly runnable in the environment
5929 provided by U-Boot; it is expected that (if they behave
5930 well) you can continue to work in U-Boot after return from
5931 the Standalone Program.
5932 "OS Kernel Images" are usually images of some Embedded OS which
5933 will take over control completely. Usually these programs
5934 will install their own set of exception handlers, device
5935 drivers, set up the MMU, etc. - this means, that you cannot
5936 expect to re-enter U-Boot except by resetting the CPU.
5937 "RAMDisk Images" are more or less just data blocks, and their
5938 parameters (address, size) are passed to an OS kernel that is
5940 "Multi-File Images" contain several images, typically an OS
5941 (Linux) kernel image and one or more data images like
5942 RAMDisks. This construct is useful for instance when you want
5943 to boot over the network using BOOTP etc., where the boot
5944 server provides just a single image file, but you want to get
5945 for instance an OS kernel and a RAMDisk image.
5947 "Multi-File Images" start with a list of image sizes, each
5948 image size (in bytes) specified by an "uint32_t" in network
5949 byte order. This list is terminated by an "(uint32_t)0".
5950 Immediately after the terminating 0 follow the images, one by
5951 one, all aligned on "uint32_t" boundaries (size rounded up to
5952 a multiple of 4 bytes).
5954 "Firmware Images" are binary images containing firmware (like
5955 U-Boot or FPGA images) which usually will be programmed to
5958 "Script files" are command sequences that will be executed by
5959 U-Boot's command interpreter; this feature is especially
5960 useful when you configure U-Boot to use a real shell (hush)
5961 as command interpreter.
5963 Booting the Linux zImage:
5964 -------------------------
5966 On some platforms, it's possible to boot Linux zImage. This is done
5967 using the "bootz" command. The syntax of "bootz" command is the same
5968 as the syntax of "bootm" command.
5970 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5971 kernel with raw initrd images. The syntax is slightly different, the
5972 address of the initrd must be augmented by it's size, in the following
5973 format: "<initrd addres>:<initrd size>".
5979 One of the features of U-Boot is that you can dynamically load and
5980 run "standalone" applications, which can use some resources of
5981 U-Boot like console I/O functions or interrupt services.
5983 Two simple examples are included with the sources:
5988 'examples/hello_world.c' contains a small "Hello World" Demo
5989 application; it is automatically compiled when you build U-Boot.
5990 It's configured to run at address 0x00040004, so you can play with it
5994 ## Ready for S-Record download ...
5995 ~>examples/hello_world.srec
5996 1 2 3 4 5 6 7 8 9 10 11 ...
5997 [file transfer complete]
5999 ## Start Addr = 0x00040004
6001 => go 40004 Hello World! This is a test.
6002 ## Starting application at 0x00040004 ...
6013 Hit any key to exit ...
6015 ## Application terminated, rc = 0x0
6017 Another example, which demonstrates how to register a CPM interrupt
6018 handler with the U-Boot code, can be found in 'examples/timer.c'.
6019 Here, a CPM timer is set up to generate an interrupt every second.
6020 The interrupt service routine is trivial, just printing a '.'
6021 character, but this is just a demo program. The application can be
6022 controlled by the following keys:
6024 ? - print current values og the CPM Timer registers
6025 b - enable interrupts and start timer
6026 e - stop timer and disable interrupts
6027 q - quit application
6030 ## Ready for S-Record download ...
6031 ~>examples/timer.srec
6032 1 2 3 4 5 6 7 8 9 10 11 ...
6033 [file transfer complete]
6035 ## Start Addr = 0x00040004
6038 ## Starting application at 0x00040004 ...
6041 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6044 [q, b, e, ?] Set interval 1000000 us
6047 [q, b, e, ?] ........
6048 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6051 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6054 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6057 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6059 [q, b, e, ?] ...Stopping timer
6061 [q, b, e, ?] ## Application terminated, rc = 0x0
6067 Over time, many people have reported problems when trying to use the
6068 "minicom" terminal emulation program for serial download. I (wd)
6069 consider minicom to be broken, and recommend not to use it. Under
6070 Unix, I recommend to use C-Kermit for general purpose use (and
6071 especially for kermit binary protocol download ("loadb" command), and
6072 use "cu" for S-Record download ("loads" command). See
6073 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6074 for help with kermit.
6077 Nevertheless, if you absolutely want to use it try adding this
6078 configuration to your "File transfer protocols" section:
6080 Name Program Name U/D FullScr IO-Red. Multi
6081 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6082 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6088 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6089 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6091 Building requires a cross environment; it is known to work on
6092 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6093 need gmake since the Makefiles are not compatible with BSD make).
6094 Note that the cross-powerpc package does not install include files;
6095 attempting to build U-Boot will fail because <machine/ansi.h> is
6096 missing. This file has to be installed and patched manually:
6098 # cd /usr/pkg/cross/powerpc-netbsd/include
6100 # ln -s powerpc machine
6101 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6102 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6104 Native builds *don't* work due to incompatibilities between native
6105 and U-Boot include files.
6107 Booting assumes that (the first part of) the image booted is a
6108 stage-2 loader which in turn loads and then invokes the kernel
6109 proper. Loader sources will eventually appear in the NetBSD source
6110 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6111 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6114 Implementation Internals:
6115 =========================
6117 The following is not intended to be a complete description of every
6118 implementation detail. However, it should help to understand the
6119 inner workings of U-Boot and make it easier to port it to custom
6123 Initial Stack, Global Data:
6124 ---------------------------
6126 The implementation of U-Boot is complicated by the fact that U-Boot
6127 starts running out of ROM (flash memory), usually without access to
6128 system RAM (because the memory controller is not initialized yet).
6129 This means that we don't have writable Data or BSS segments, and BSS
6130 is not initialized as zero. To be able to get a C environment working
6131 at all, we have to allocate at least a minimal stack. Implementation
6132 options for this are defined and restricted by the CPU used: Some CPU
6133 models provide on-chip memory (like the IMMR area on MPC8xx and
6134 MPC826x processors), on others (parts of) the data cache can be
6135 locked as (mis-) used as memory, etc.
6137 Chris Hallinan posted a good summary of these issues to the
6138 U-Boot mailing list:
6140 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6142 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6145 Correct me if I'm wrong, folks, but the way I understand it
6146 is this: Using DCACHE as initial RAM for Stack, etc, does not
6147 require any physical RAM backing up the cache. The cleverness
6148 is that the cache is being used as a temporary supply of
6149 necessary storage before the SDRAM controller is setup. It's
6150 beyond the scope of this list to explain the details, but you
6151 can see how this works by studying the cache architecture and
6152 operation in the architecture and processor-specific manuals.
6154 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6155 is another option for the system designer to use as an
6156 initial stack/RAM area prior to SDRAM being available. Either
6157 option should work for you. Using CS 4 should be fine if your
6158 board designers haven't used it for something that would
6159 cause you grief during the initial boot! It is frequently not
6162 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6163 with your processor/board/system design. The default value
6164 you will find in any recent u-boot distribution in
6165 walnut.h should work for you. I'd set it to a value larger
6166 than your SDRAM module. If you have a 64MB SDRAM module, set
6167 it above 400_0000. Just make sure your board has no resources
6168 that are supposed to respond to that address! That code in
6169 start.S has been around a while and should work as is when
6170 you get the config right.
6175 It is essential to remember this, since it has some impact on the C
6176 code for the initialization procedures:
6178 * Initialized global data (data segment) is read-only. Do not attempt
6181 * Do not use any uninitialized global data (or implicitely initialized
6182 as zero data - BSS segment) at all - this is undefined, initiali-
6183 zation is performed later (when relocating to RAM).
6185 * Stack space is very limited. Avoid big data buffers or things like
6188 Having only the stack as writable memory limits means we cannot use
6189 normal global data to share information beween the code. But it
6190 turned out that the implementation of U-Boot can be greatly
6191 simplified by making a global data structure (gd_t) available to all
6192 functions. We could pass a pointer to this data as argument to _all_
6193 functions, but this would bloat the code. Instead we use a feature of
6194 the GCC compiler (Global Register Variables) to share the data: we
6195 place a pointer (gd) to the global data into a register which we
6196 reserve for this purpose.
6198 When choosing a register for such a purpose we are restricted by the
6199 relevant (E)ABI specifications for the current architecture, and by
6200 GCC's implementation.
6202 For PowerPC, the following registers have specific use:
6204 R2: reserved for system use
6205 R3-R4: parameter passing and return values
6206 R5-R10: parameter passing
6207 R13: small data area pointer
6211 (U-Boot also uses R12 as internal GOT pointer. r12
6212 is a volatile register so r12 needs to be reset when
6213 going back and forth between asm and C)
6215 ==> U-Boot will use R2 to hold a pointer to the global data
6217 Note: on PPC, we could use a static initializer (since the
6218 address of the global data structure is known at compile time),
6219 but it turned out that reserving a register results in somewhat
6220 smaller code - although the code savings are not that big (on
6221 average for all boards 752 bytes for the whole U-Boot image,
6222 624 text + 127 data).
6224 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6225 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6227 ==> U-Boot will use P3 to hold a pointer to the global data
6229 On ARM, the following registers are used:
6231 R0: function argument word/integer result
6232 R1-R3: function argument word
6233 R9: platform specific
6234 R10: stack limit (used only if stack checking is enabled)
6235 R11: argument (frame) pointer
6236 R12: temporary workspace
6239 R15: program counter
6241 ==> U-Boot will use R9 to hold a pointer to the global data
6243 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6245 On Nios II, the ABI is documented here:
6246 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6248 ==> U-Boot will use gp to hold a pointer to the global data
6250 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6251 to access small data sections, so gp is free.
6253 On NDS32, the following registers are used:
6255 R0-R1: argument/return
6257 R15: temporary register for assembler
6258 R16: trampoline register
6259 R28: frame pointer (FP)
6260 R29: global pointer (GP)
6261 R30: link register (LP)
6262 R31: stack pointer (SP)
6263 PC: program counter (PC)
6265 ==> U-Boot will use R10 to hold a pointer to the global data
6267 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6268 or current versions of GCC may "optimize" the code too much.
6273 U-Boot runs in system state and uses physical addresses, i.e. the
6274 MMU is not used either for address mapping nor for memory protection.
6276 The available memory is mapped to fixed addresses using the memory
6277 controller. In this process, a contiguous block is formed for each
6278 memory type (Flash, SDRAM, SRAM), even when it consists of several
6279 physical memory banks.
6281 U-Boot is installed in the first 128 kB of the first Flash bank (on
6282 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6283 booting and sizing and initializing DRAM, the code relocates itself
6284 to the upper end of DRAM. Immediately below the U-Boot code some
6285 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6286 configuration setting]. Below that, a structure with global Board
6287 Info data is placed, followed by the stack (growing downward).
6289 Additionally, some exception handler code is copied to the low 8 kB
6290 of DRAM (0x00000000 ... 0x00001FFF).
6292 So a typical memory configuration with 16 MB of DRAM could look like
6295 0x0000 0000 Exception Vector code
6298 0x0000 2000 Free for Application Use
6304 0x00FB FF20 Monitor Stack (Growing downward)
6305 0x00FB FFAC Board Info Data and permanent copy of global data
6306 0x00FC 0000 Malloc Arena
6309 0x00FE 0000 RAM Copy of Monitor Code
6310 ... eventually: LCD or video framebuffer
6311 ... eventually: pRAM (Protected RAM - unchanged by reset)
6312 0x00FF FFFF [End of RAM]
6315 System Initialization:
6316 ----------------------
6318 In the reset configuration, U-Boot starts at the reset entry point
6319 (on most PowerPC systems at address 0x00000100). Because of the reset
6320 configuration for CS0# this is a mirror of the onboard Flash memory.
6321 To be able to re-map memory U-Boot then jumps to its link address.
6322 To be able to implement the initialization code in C, a (small!)
6323 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6324 which provide such a feature like MPC8xx or MPC8260), or in a locked
6325 part of the data cache. After that, U-Boot initializes the CPU core,
6326 the caches and the SIU.
6328 Next, all (potentially) available memory banks are mapped using a
6329 preliminary mapping. For example, we put them on 512 MB boundaries
6330 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6331 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6332 programmed for SDRAM access. Using the temporary configuration, a
6333 simple memory test is run that determines the size of the SDRAM
6336 When there is more than one SDRAM bank, and the banks are of
6337 different size, the largest is mapped first. For equal size, the first
6338 bank (CS2#) is mapped first. The first mapping is always for address
6339 0x00000000, with any additional banks following immediately to create
6340 contiguous memory starting from 0.
6342 Then, the monitor installs itself at the upper end of the SDRAM area
6343 and allocates memory for use by malloc() and for the global Board
6344 Info data; also, the exception vector code is copied to the low RAM
6345 pages, and the final stack is set up.
6347 Only after this relocation will you have a "normal" C environment;
6348 until that you are restricted in several ways, mostly because you are
6349 running from ROM, and because the code will have to be relocated to a
6353 U-Boot Porting Guide:
6354 ----------------------
6356 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6360 int main(int argc, char *argv[])
6362 sighandler_t no_more_time;
6364 signal(SIGALRM, no_more_time);
6365 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6367 if (available_money > available_manpower) {
6368 Pay consultant to port U-Boot;
6372 Download latest U-Boot source;
6374 Subscribe to u-boot mailing list;
6377 email("Hi, I am new to U-Boot, how do I get started?");
6380 Read the README file in the top level directory;
6381 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6382 Read applicable doc/*.README;
6383 Read the source, Luke;
6384 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6387 if (available_money > toLocalCurrency ($2500))
6390 Add a lot of aggravation and time;
6392 if (a similar board exists) { /* hopefully... */
6393 cp -a board/<similar> board/<myboard>
6394 cp include/configs/<similar>.h include/configs/<myboard>.h
6396 Create your own board support subdirectory;
6397 Create your own board include/configs/<myboard>.h file;
6399 Edit new board/<myboard> files
6400 Edit new include/configs/<myboard>.h
6405 Add / modify source code;
6409 email("Hi, I am having problems...");
6411 Send patch file to the U-Boot email list;
6412 if (reasonable critiques)
6413 Incorporate improvements from email list code review;
6415 Defend code as written;
6421 void no_more_time (int sig)
6430 All contributions to U-Boot should conform to the Linux kernel
6431 coding style; see the file "Documentation/CodingStyle" and the script
6432 "scripts/Lindent" in your Linux kernel source directory.
6434 Source files originating from a different project (for example the
6435 MTD subsystem) are generally exempt from these guidelines and are not
6436 reformated to ease subsequent migration to newer versions of those
6439 Please note that U-Boot is implemented in C (and to some small parts in
6440 Assembler); no C++ is used, so please do not use C++ style comments (//)
6443 Please also stick to the following formatting rules:
6444 - remove any trailing white space
6445 - use TAB characters for indentation and vertical alignment, not spaces
6446 - make sure NOT to use DOS '\r\n' line feeds
6447 - do not add more than 2 consecutive empty lines to source files
6448 - do not add trailing empty lines to source files
6450 Submissions which do not conform to the standards may be returned
6451 with a request to reformat the changes.
6457 Since the number of patches for U-Boot is growing, we need to
6458 establish some rules. Submissions which do not conform to these rules
6459 may be rejected, even when they contain important and valuable stuff.
6461 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6464 see http://lists.denx.de/mailman/listinfo/u-boot
6466 When you send a patch, please include the following information with
6469 * For bug fixes: a description of the bug and how your patch fixes
6470 this bug. Please try to include a way of demonstrating that the
6471 patch actually fixes something.
6473 * For new features: a description of the feature and your
6476 * A CHANGELOG entry as plaintext (separate from the patch)
6478 * For major contributions, your entry to the CREDITS file
6480 * When you add support for a new board, don't forget to add a
6481 maintainer e-mail address to the boards.cfg file, too.
6483 * If your patch adds new configuration options, don't forget to
6484 document these in the README file.
6486 * The patch itself. If you are using git (which is *strongly*
6487 recommended) you can easily generate the patch using the
6488 "git format-patch". If you then use "git send-email" to send it to
6489 the U-Boot mailing list, you will avoid most of the common problems
6490 with some other mail clients.
6492 If you cannot use git, use "diff -purN OLD NEW". If your version of
6493 diff does not support these options, then get the latest version of
6496 The current directory when running this command shall be the parent
6497 directory of the U-Boot source tree (i. e. please make sure that
6498 your patch includes sufficient directory information for the
6501 We prefer patches as plain text. MIME attachments are discouraged,
6502 and compressed attachments must not be used.
6504 * If one logical set of modifications affects or creates several
6505 files, all these changes shall be submitted in a SINGLE patch file.
6507 * Changesets that contain different, unrelated modifications shall be
6508 submitted as SEPARATE patches, one patch per changeset.
6513 * Before sending the patch, run the MAKEALL script on your patched
6514 source tree and make sure that no errors or warnings are reported
6515 for any of the boards.
6517 * Keep your modifications to the necessary minimum: A patch
6518 containing several unrelated changes or arbitrary reformats will be
6519 returned with a request to re-formatting / split it.
6521 * If you modify existing code, make sure that your new code does not
6522 add to the memory footprint of the code ;-) Small is beautiful!
6523 When adding new features, these should compile conditionally only
6524 (using #ifdef), and the resulting code with the new feature
6525 disabled must not need more memory than the old code without your
6528 * Remember that there is a size limit of 100 kB per message on the
6529 u-boot mailing list. Bigger patches will be moderated. If they are
6530 reasonable and not too big, they will be acknowledged. But patches
6531 bigger than the size limit should be avoided.
projects / u-boot.git / blob