2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG and CREDITS files to find out
38 who contributed the specific port. The boards.cfg file lists board
41 Note: There is no CHANGELOG file in the actual U-Boot source tree;
42 it can be created dynamically from the Git log using:
50 In case you have questions about, problems with or contributions for
51 U-Boot you should send a message to the U-Boot mailing list at
52 <u-boot@lists.denx.de>. There is also an archive of previous traffic
53 on the mailing list - please search the archive before asking FAQ's.
54 Please see http://lists.denx.de/pipermail/u-boot and
55 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
58 Where to get source code:
59 =========================
61 The U-Boot source code is maintained in the git repository at
62 git://www.denx.de/git/u-boot.git ; you can browse it online at
63 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
65 The "snapshot" links on this page allow you to download tarballs of
66 any version you might be interested in. Official releases are also
67 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
70 Pre-built (and tested) images are available from
71 ftp://ftp.denx.de/pub/u-boot/images/
77 - start from 8xxrom sources
78 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
80 - make it easier to add custom boards
81 - make it possible to add other [PowerPC] CPUs
82 - extend functions, especially:
83 * Provide extended interface to Linux boot loader
86 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
87 - create ARMBoot project (http://sourceforge.net/projects/armboot)
88 - add other CPU families (starting with ARM)
89 - create U-Boot project (http://sourceforge.net/projects/u-boot)
90 - current project page: see http://www.denx.de/wiki/U-Boot
96 The "official" name of this project is "Das U-Boot". The spelling
97 "U-Boot" shall be used in all written text (documentation, comments
98 in source files etc.). Example:
100 This is the README file for the U-Boot project.
102 File names etc. shall be based on the string "u-boot". Examples:
104 include/asm-ppc/u-boot.h
106 #include <asm/u-boot.h>
108 Variable names, preprocessor constants etc. shall be either based on
109 the string "u_boot" or on "U_BOOT". Example:
111 U_BOOT_VERSION u_boot_logo
112 IH_OS_U_BOOT u_boot_hush_start
118 Starting with the release in October 2008, the names of the releases
119 were changed from numerical release numbers without deeper meaning
120 into a time stamp based numbering. Regular releases are identified by
121 names consisting of the calendar year and month of the release date.
122 Additional fields (if present) indicate release candidates or bug fix
123 releases in "stable" maintenance trees.
126 U-Boot v2009.11 - Release November 2009
127 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
128 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
134 /arch Architecture specific files
135 /arc Files generic to ARC architecture
136 /cpu CPU specific files
137 /arc700 Files specific to ARC 700 CPUs
138 /lib Architecture specific library files
139 /arm Files generic to ARM architecture
140 /cpu CPU specific files
141 /arm720t Files specific to ARM 720 CPUs
142 /arm920t Files specific to ARM 920 CPUs
143 /at91 Files specific to Atmel AT91RM9200 CPU
144 /imx Files specific to Freescale MC9328 i.MX CPUs
145 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
146 /arm926ejs Files specific to ARM 926 CPUs
147 /arm1136 Files specific to ARM 1136 CPUs
148 /pxa Files specific to Intel XScale PXA CPUs
149 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
150 /lib Architecture specific library files
151 /avr32 Files generic to AVR32 architecture
152 /cpu CPU specific files
153 /lib Architecture specific library files
154 /blackfin Files generic to Analog Devices Blackfin architecture
155 /cpu CPU specific files
156 /lib Architecture specific library files
157 /m68k Files generic to m68k architecture
158 /cpu CPU specific files
159 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
160 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
161 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
162 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
163 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
164 /lib Architecture specific library files
165 /microblaze Files generic to microblaze architecture
166 /cpu CPU specific files
167 /lib Architecture specific library files
168 /mips Files generic to MIPS architecture
169 /cpu CPU specific files
170 /mips32 Files specific to MIPS32 CPUs
171 /mips64 Files specific to MIPS64 CPUs
172 /lib Architecture specific library files
173 /nds32 Files generic to NDS32 architecture
174 /cpu CPU specific files
175 /n1213 Files specific to Andes Technology N1213 CPUs
176 /lib Architecture specific library files
177 /nios2 Files generic to Altera NIOS2 architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /openrisc Files generic to OpenRISC architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /powerpc Files generic to PowerPC architecture
184 /cpu CPU specific files
185 /mpc5xx Files specific to Freescale MPC5xx CPUs
186 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
187 /mpc8xx Files specific to Freescale MPC8xx CPUs
188 /mpc8260 Files specific to Freescale MPC8260 CPUs
189 /mpc85xx Files specific to Freescale MPC85xx CPUs
190 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
191 /lib Architecture specific library files
192 /sh Files generic to SH architecture
193 /cpu CPU specific files
194 /sh2 Files specific to sh2 CPUs
195 /sh3 Files specific to sh3 CPUs
196 /sh4 Files specific to sh4 CPUs
197 /lib Architecture specific library files
198 /sparc Files generic to SPARC architecture
199 /cpu CPU specific files
200 /leon2 Files specific to Gaisler LEON2 SPARC CPU
201 /leon3 Files specific to Gaisler LEON3 SPARC CPU
202 /lib Architecture specific library files
203 /x86 Files generic to x86 architecture
204 /cpu CPU specific files
205 /lib Architecture specific library files
206 /api Machine/arch independent API for external apps
207 /board Board dependent files
208 /common Misc architecture independent functions
209 /disk Code for disk drive partition handling
210 /doc Documentation (don't expect too much)
211 /drivers Commonly used device drivers
212 /dts Contains Makefile for building internal U-Boot fdt.
213 /examples Example code for standalone applications, etc.
214 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
215 /include Header Files
216 /lib Files generic to all architectures
217 /libfdt Library files to support flattened device trees
218 /lzma Library files to support LZMA decompression
219 /lzo Library files to support LZO decompression
221 /post Power On Self Test
222 /spl Secondary Program Loader framework
223 /tools Tools to build S-Record or U-Boot images, etc.
225 Software Configuration:
226 =======================
228 Configuration is usually done using C preprocessor defines; the
229 rationale behind that is to avoid dead code whenever possible.
231 There are two classes of configuration variables:
233 * Configuration _OPTIONS_:
234 These are selectable by the user and have names beginning with
237 * Configuration _SETTINGS_:
238 These depend on the hardware etc. and should not be meddled with if
239 you don't know what you're doing; they have names beginning with
242 Later we will add a configuration tool - probably similar to or even
243 identical to what's used for the Linux kernel. Right now, we have to
244 do the configuration by hand, which means creating some symbolic
245 links and editing some configuration files. We use the TQM8xxL boards
249 Selection of Processor Architecture and Board Type:
250 ---------------------------------------------------
252 For all supported boards there are ready-to-use default
253 configurations available; just type "make <board_name>_defconfig".
255 Example: For a TQM823L module type:
258 make TQM823L_defconfig
260 For the Cogent platform, you need to specify the CPU type as well;
261 e.g. "make cogent_mpc8xx_defconfig". And also configure the cogent
262 directory according to the instructions in cogent/README.
268 U-Boot can be built natively to run on a Linux host using the 'sandbox'
269 board. This allows feature development which is not board- or architecture-
270 specific to be undertaken on a native platform. The sandbox is also used to
271 run some of U-Boot's tests.
273 See board/sandbox/README.sandbox for more details.
276 Board Initialisation Flow:
277 --------------------------
279 This is the intended start-up flow for boards. This should apply for both
280 SPL and U-Boot proper (i.e. they both follow the same rules). At present SPL
281 mostly uses a separate code path, but the funtion names and roles of each
282 function are the same. Some boards or architectures may not conform to this.
283 At least most ARM boards which use CONFIG_SPL_FRAMEWORK conform to this.
285 Execution starts with start.S with three functions called during init after
286 that. The purpose and limitations of each is described below.
289 - purpose: essential init to permit execution to reach board_init_f()
290 - no global_data or BSS
291 - there is no stack (ARMv7 may have one but it will soon be removed)
292 - must not set up SDRAM or use console
293 - must only do the bare minimum to allow execution to continue to
295 - this is almost never needed
296 - return normally from this function
299 - purpose: set up the machine ready for running board_init_r():
300 i.e. SDRAM and serial UART
301 - global_data is available
303 - BSS is not available, so you cannot use global/static variables,
304 only stack variables and global_data
306 Non-SPL-specific notes:
307 - dram_init() is called to set up DRAM. If already done in SPL this
311 - you can override the entire board_init_f() function with your own
313 - preloader_console_init() can be called here in extremis
314 - should set up SDRAM, and anything needed to make the UART work
315 - these is no need to clear BSS, it will be done by crt0.S
316 - must return normally from this function (don't call board_init_r()
319 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
320 this point the stack and global_data are relocated to below
321 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
325 - purpose: main execution, common code
326 - global_data is available
328 - BSS is available, all static/global variables can be used
329 - execution eventually continues to main_loop()
331 Non-SPL-specific notes:
332 - U-Boot is relocated to the top of memory and is now running from
336 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
337 CONFIG_SPL_STACK_R_ADDR points into SDRAM
338 - preloader_console_init() can be called here - typically this is
339 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
340 spl_board_init() function containing this call
341 - loads U-Boot or (in falcon mode) Linux
345 Configuration Options:
346 ----------------------
348 Configuration depends on the combination of board and CPU type; all
349 such information is kept in a configuration file
350 "include/configs/<board_name>.h".
352 Example: For a TQM823L module, all configuration settings are in
353 "include/configs/TQM823L.h".
356 Many of the options are named exactly as the corresponding Linux
357 kernel configuration options. The intention is to make it easier to
358 build a config tool - later.
361 The following options need to be configured:
363 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
365 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
367 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
368 Define exactly one, e.g. CONFIG_ATSTK1002
370 - CPU Module Type: (if CONFIG_COGENT is defined)
371 Define exactly one of
373 --- FIXME --- not tested yet:
374 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
375 CONFIG_CMA287_23, CONFIG_CMA287_50
377 - Motherboard Type: (if CONFIG_COGENT is defined)
378 Define exactly one of
379 CONFIG_CMA101, CONFIG_CMA102
381 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
382 Define one or more of
385 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
386 Define one or more of
387 CONFIG_LCD_HEARTBEAT - update a character position on
388 the LCD display every second with
391 - Marvell Family Member
392 CONFIG_SYS_MVFS - define it if you want to enable
393 multiple fs option at one time
394 for marvell soc family
396 - 8xx CPU Options: (if using an MPC8xx CPU)
397 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
398 get_gclk_freq() cannot work
399 e.g. if there is no 32KHz
400 reference PIT/RTC clock
401 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
404 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
405 CONFIG_SYS_8xx_CPUCLK_MIN
406 CONFIG_SYS_8xx_CPUCLK_MAX
407 CONFIG_8xx_CPUCLK_DEFAULT
408 See doc/README.MPC866
410 CONFIG_SYS_MEASURE_CPUCLK
412 Define this to measure the actual CPU clock instead
413 of relying on the correctness of the configured
414 values. Mostly useful for board bringup to make sure
415 the PLL is locked at the intended frequency. Note
416 that this requires a (stable) reference clock (32 kHz
417 RTC clock or CONFIG_SYS_8XX_XIN)
419 CONFIG_SYS_DELAYED_ICACHE
421 Define this option if you want to enable the
422 ICache only when Code runs from RAM.
427 Specifies that the core is a 64-bit PowerPC implementation (implements
428 the "64" category of the Power ISA). This is necessary for ePAPR
429 compliance, among other possible reasons.
431 CONFIG_SYS_FSL_TBCLK_DIV
433 Defines the core time base clock divider ratio compared to the
434 system clock. On most PQ3 devices this is 8, on newer QorIQ
435 devices it can be 16 or 32. The ratio varies from SoC to Soc.
437 CONFIG_SYS_FSL_PCIE_COMPAT
439 Defines the string to utilize when trying to match PCIe device
440 tree nodes for the given platform.
442 CONFIG_SYS_PPC_E500_DEBUG_TLB
444 Enables a temporary TLB entry to be used during boot to work
445 around limitations in e500v1 and e500v2 external debugger
446 support. This reduces the portions of the boot code where
447 breakpoints and single stepping do not work. The value of this
448 symbol should be set to the TLB1 entry to be used for this
451 CONFIG_SYS_FSL_ERRATUM_A004510
453 Enables a workaround for erratum A004510. If set,
454 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
455 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
457 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
458 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
460 Defines one or two SoC revisions (low 8 bits of SVR)
461 for which the A004510 workaround should be applied.
463 The rest of SVR is either not relevant to the decision
464 of whether the erratum is present (e.g. p2040 versus
465 p2041) or is implied by the build target, which controls
466 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
468 See Freescale App Note 4493 for more information about
471 CONFIG_A003399_NOR_WORKAROUND
472 Enables a workaround for IFC erratum A003399. It is only
473 required during NOR boot.
475 CONFIG_A008044_WORKAROUND
476 Enables a workaround for T1040/T1042 erratum A008044. It is only
477 required during NAND boot and valid for Rev 1.0 SoC revision
479 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
481 This is the value to write into CCSR offset 0x18600
482 according to the A004510 workaround.
484 CONFIG_SYS_FSL_DSP_DDR_ADDR
485 This value denotes start offset of DDR memory which is
486 connected exclusively to the DSP cores.
488 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
489 This value denotes start offset of M2 memory
490 which is directly connected to the DSP core.
492 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
493 This value denotes start offset of M3 memory which is directly
494 connected to the DSP core.
496 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
497 This value denotes start offset of DSP CCSR space.
499 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
500 Single Source Clock is clocking mode present in some of FSL SoC's.
501 In this mode, a single differential clock is used to supply
502 clocks to the sysclock, ddrclock and usbclock.
504 CONFIG_SYS_CPC_REINIT_F
505 This CONFIG is defined when the CPC is configured as SRAM at the
506 time of U-boot entry and is required to be re-initialized.
509 Indicates this SoC supports deep sleep feature. If deep sleep is
510 supported, core will start to execute uboot when wakes up.
512 - Generic CPU options:
513 CONFIG_SYS_GENERIC_GLOBAL_DATA
514 Defines global data is initialized in generic board board_init_f().
515 If this macro is defined, global data is created and cleared in
516 generic board board_init_f(). Without this macro, architecture/board
517 should initialize global data before calling board_init_f().
519 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
521 Defines the endianess of the CPU. Implementation of those
522 values is arch specific.
525 Freescale DDR driver in use. This type of DDR controller is
526 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
529 CONFIG_SYS_FSL_DDR_ADDR
530 Freescale DDR memory-mapped register base.
532 CONFIG_SYS_FSL_DDR_EMU
533 Specify emulator support for DDR. Some DDR features such as
534 deskew training are not available.
536 CONFIG_SYS_FSL_DDRC_GEN1
537 Freescale DDR1 controller.
539 CONFIG_SYS_FSL_DDRC_GEN2
540 Freescale DDR2 controller.
542 CONFIG_SYS_FSL_DDRC_GEN3
543 Freescale DDR3 controller.
545 CONFIG_SYS_FSL_DDRC_GEN4
546 Freescale DDR4 controller.
548 CONFIG_SYS_FSL_DDRC_ARM_GEN3
549 Freescale DDR3 controller for ARM-based SoCs.
552 Board config to use DDR1. It can be enabled for SoCs with
553 Freescale DDR1 or DDR2 controllers, depending on the board
557 Board config to use DDR2. It can be eanbeld for SoCs with
558 Freescale DDR2 or DDR3 controllers, depending on the board
562 Board config to use DDR3. It can be enabled for SoCs with
563 Freescale DDR3 or DDR3L controllers.
566 Board config to use DDR3L. It can be enabled for SoCs with
570 Board config to use DDR4. It can be enabled for SoCs with
573 CONFIG_SYS_FSL_IFC_BE
574 Defines the IFC controller register space as Big Endian
576 CONFIG_SYS_FSL_IFC_LE
577 Defines the IFC controller register space as Little Endian
579 CONFIG_SYS_FSL_PBL_PBI
580 It enables addition of RCW (Power on reset configuration) in built image.
581 Please refer doc/README.pblimage for more details
583 CONFIG_SYS_FSL_PBL_RCW
584 It adds PBI(pre-boot instructions) commands in u-boot build image.
585 PBI commands can be used to configure SoC before it starts the execution.
586 Please refer doc/README.pblimage for more details
589 It adds a target to create boot binary having SPL binary in PBI format
590 concatenated with u-boot binary.
592 CONFIG_SYS_FSL_DDR_BE
593 Defines the DDR controller register space as Big Endian
595 CONFIG_SYS_FSL_DDR_LE
596 Defines the DDR controller register space as Little Endian
598 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
599 Physical address from the view of DDR controllers. It is the
600 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
601 it could be different for ARM SoCs.
603 CONFIG_SYS_FSL_DDR_INTLV_256B
604 DDR controller interleaving on 256-byte. This is a special
605 interleaving mode, handled by Dickens for Freescale layerscape
608 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
609 Number of controllers used as main memory.
611 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
612 Number of controllers used for other than main memory.
614 CONFIG_SYS_FSL_SEC_BE
615 Defines the SEC controller register space as Big Endian
617 CONFIG_SYS_FSL_SEC_LE
618 Defines the SEC controller register space as Little Endian
620 - Intel Monahans options:
621 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
623 Defines the Monahans run mode to oscillator
624 ratio. Valid values are 8, 16, 24, 31. The core
625 frequency is this value multiplied by 13 MHz.
627 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
629 Defines the Monahans turbo mode to oscillator
630 ratio. Valid values are 1 (default if undefined) and
631 2. The core frequency as calculated above is multiplied
635 CONFIG_SYS_INIT_SP_OFFSET
637 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
638 pointer. This is needed for the temporary stack before
641 CONFIG_SYS_MIPS_CACHE_MODE
643 Cache operation mode for the MIPS CPU.
644 See also arch/mips/include/asm/mipsregs.h.
646 CONF_CM_CACHABLE_NO_WA
649 CONF_CM_CACHABLE_NONCOHERENT
653 CONF_CM_CACHABLE_ACCELERATED
655 CONFIG_SYS_XWAY_EBU_BOOTCFG
657 Special option for Lantiq XWAY SoCs for booting from NOR flash.
658 See also arch/mips/cpu/mips32/start.S.
660 CONFIG_XWAY_SWAP_BYTES
662 Enable compilation of tools/xway-swap-bytes needed for Lantiq
663 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
664 be swapped if a flash programmer is used.
667 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
669 Select high exception vectors of the ARM core, e.g., do not
670 clear the V bit of the c1 register of CP15.
672 CONFIG_SYS_THUMB_BUILD
674 Use this flag to build U-Boot using the Thumb instruction
675 set for ARM architectures. Thumb instruction set provides
676 better code density. For ARM architectures that support
677 Thumb2 this flag will result in Thumb2 code generated by
680 CONFIG_ARM_ERRATA_716044
681 CONFIG_ARM_ERRATA_742230
682 CONFIG_ARM_ERRATA_743622
683 CONFIG_ARM_ERRATA_751472
684 CONFIG_ARM_ERRATA_761320
685 CONFIG_ARM_ERRATA_773022
686 CONFIG_ARM_ERRATA_774769
687 CONFIG_ARM_ERRATA_794072
689 If set, the workarounds for these ARM errata are applied early
690 during U-Boot startup. Note that these options force the
691 workarounds to be applied; no CPU-type/version detection
692 exists, unlike the similar options in the Linux kernel. Do not
693 set these options unless they apply!
696 Generic timer clock source frequency.
698 COUNTER_FREQUENCY_REAL
699 Generic timer clock source frequency if the real clock is
700 different from COUNTER_FREQUENCY, and can only be determined
703 NOTE: The following can be machine specific errata. These
704 do have ability to provide rudimentary version and machine
705 specific checks, but expect no product checks.
706 CONFIG_ARM_ERRATA_430973
707 CONFIG_ARM_ERRATA_454179
708 CONFIG_ARM_ERRATA_621766
709 CONFIG_ARM_ERRATA_798870
710 CONFIG_ARM_ERRATA_801819
713 CONFIG_TEGRA_SUPPORT_NON_SECURE
715 Support executing U-Boot in non-secure (NS) mode. Certain
716 impossible actions will be skipped if the CPU is in NS mode,
717 such as ARM architectural timer initialization.
719 - Linux Kernel Interface:
722 U-Boot stores all clock information in Hz
723 internally. For binary compatibility with older Linux
724 kernels (which expect the clocks passed in the
725 bd_info data to be in MHz) the environment variable
726 "clocks_in_mhz" can be defined so that U-Boot
727 converts clock data to MHZ before passing it to the
729 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
730 "clocks_in_mhz=1" is automatically included in the
733 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
735 When transferring memsize parameter to Linux, some versions
736 expect it to be in bytes, others in MB.
737 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
741 New kernel versions are expecting firmware settings to be
742 passed using flattened device trees (based on open firmware
746 * New libfdt-based support
747 * Adds the "fdt" command
748 * The bootm command automatically updates the fdt
750 OF_CPU - The proper name of the cpus node (only required for
751 MPC512X and MPC5xxx based boards).
752 OF_SOC - The proper name of the soc node (only required for
753 MPC512X and MPC5xxx based boards).
754 OF_TBCLK - The timebase frequency.
755 OF_STDOUT_PATH - The path to the console device
757 boards with QUICC Engines require OF_QE to set UCC MAC
760 CONFIG_OF_BOARD_SETUP
762 Board code has addition modification that it wants to make
763 to the flat device tree before handing it off to the kernel
765 CONFIG_OF_SYSTEM_SETUP
767 Other code has addition modification that it wants to make
768 to the flat device tree before handing it off to the kernel.
769 This causes ft_system_setup() to be called before booting
774 This define fills in the correct boot CPU in the boot
775 param header, the default value is zero if undefined.
779 U-Boot can detect if an IDE device is present or not.
780 If not, and this new config option is activated, U-Boot
781 removes the ATA node from the DTS before booting Linux,
782 so the Linux IDE driver does not probe the device and
783 crash. This is needed for buggy hardware (uc101) where
784 no pull down resistor is connected to the signal IDE5V_DD7.
786 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
788 This setting is mandatory for all boards that have only one
789 machine type and must be used to specify the machine type
790 number as it appears in the ARM machine registry
791 (see http://www.arm.linux.org.uk/developer/machines/).
792 Only boards that have multiple machine types supported
793 in a single configuration file and the machine type is
794 runtime discoverable, do not have to use this setting.
796 - vxWorks boot parameters:
798 bootvx constructs a valid bootline using the following
799 environments variables: bootdev, bootfile, ipaddr, netmask,
800 serverip, gatewayip, hostname, othbootargs.
801 It loads the vxWorks image pointed bootfile.
803 Note: If a "bootargs" environment is defined, it will overwride
804 the defaults discussed just above.
806 - Cache Configuration:
807 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
808 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
809 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
811 - Cache Configuration for ARM:
812 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
814 CONFIG_SYS_PL310_BASE - Physical base address of PL310
815 controller register space
820 Define this if you want support for Amba PrimeCell PL010 UARTs.
824 Define this if you want support for Amba PrimeCell PL011 UARTs.
828 If you have Amba PrimeCell PL011 UARTs, set this variable to
829 the clock speed of the UARTs.
833 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
834 define this to a list of base addresses for each (supported)
835 port. See e.g. include/configs/versatile.h
837 CONFIG_SERIAL_HW_FLOW_CONTROL
839 Define this variable to enable hw flow control in serial driver.
840 Current user of this option is drivers/serial/nsl16550.c driver
843 Depending on board, define exactly one serial port
844 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
845 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
846 console by defining CONFIG_8xx_CONS_NONE
848 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
849 port routines must be defined elsewhere
850 (i.e. serial_init(), serial_getc(), ...)
853 Enables console device for a color framebuffer. Needs following
854 defines (cf. smiLynxEM, i8042)
855 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
857 VIDEO_HW_RECTFILL graphic chip supports
860 VIDEO_HW_BITBLT graphic chip supports
861 bit-blit (cf. smiLynxEM)
862 VIDEO_VISIBLE_COLS visible pixel columns
864 VIDEO_VISIBLE_ROWS visible pixel rows
865 VIDEO_PIXEL_SIZE bytes per pixel
866 VIDEO_DATA_FORMAT graphic data format
867 (0-5, cf. cfb_console.c)
868 VIDEO_FB_ADRS framebuffer address
869 VIDEO_KBD_INIT_FCT keyboard int fct
870 (i.e. i8042_kbd_init())
871 VIDEO_TSTC_FCT test char fct
873 VIDEO_GETC_FCT get char fct
875 CONFIG_CONSOLE_CURSOR cursor drawing on/off
876 (requires blink timer
878 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
879 CONFIG_CONSOLE_TIME display time/date info in
881 (requires CONFIG_CMD_DATE)
882 CONFIG_VIDEO_LOGO display Linux logo in
884 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
885 linux_logo.h for logo.
886 Requires CONFIG_VIDEO_LOGO
887 CONFIG_CONSOLE_EXTRA_INFO
888 additional board info beside
891 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
892 a limited number of ANSI escape sequences (cursor control,
893 erase functions and limited graphics rendition control).
895 When CONFIG_CFB_CONSOLE is defined, video console is
896 default i/o. Serial console can be forced with
897 environment 'console=serial'.
899 When CONFIG_SILENT_CONSOLE is defined, all console
900 messages (by U-Boot and Linux!) can be silenced with
901 the "silent" environment variable. See
902 doc/README.silent for more information.
904 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
906 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
910 CONFIG_BAUDRATE - in bps
911 Select one of the baudrates listed in
912 CONFIG_SYS_BAUDRATE_TABLE, see below.
913 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
915 - Console Rx buffer length
916 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
917 the maximum receive buffer length for the SMC.
918 This option is actual only for 82xx and 8xx possible.
919 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
920 must be defined, to setup the maximum idle timeout for
923 - Pre-Console Buffer:
924 Prior to the console being initialised (i.e. serial UART
925 initialised etc) all console output is silently discarded.
926 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
927 buffer any console messages prior to the console being
928 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
929 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
930 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
931 bytes are output before the console is initialised, the
932 earlier bytes are discarded.
934 Note that when printing the buffer a copy is made on the
935 stack so CONFIG_PRE_CON_BUF_SZ must fit on the stack.
937 'Sane' compilers will generate smaller code if
938 CONFIG_PRE_CON_BUF_SZ is a power of 2
940 - Safe printf() functions
941 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
942 the printf() functions. These are defined in
943 include/vsprintf.h and include snprintf(), vsnprintf() and
944 so on. Code size increase is approximately 300-500 bytes.
945 If this option is not given then these functions will
946 silently discard their buffer size argument - this means
947 you are not getting any overflow checking in this case.
949 - Boot Delay: CONFIG_BOOTDELAY - in seconds
950 Delay before automatically booting the default image;
951 set to -1 to disable autoboot.
952 set to -2 to autoboot with no delay and not check for abort
953 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
955 See doc/README.autoboot for these options that
956 work with CONFIG_BOOTDELAY. None are required.
957 CONFIG_BOOT_RETRY_TIME
958 CONFIG_BOOT_RETRY_MIN
959 CONFIG_AUTOBOOT_KEYED
960 CONFIG_AUTOBOOT_PROMPT
961 CONFIG_AUTOBOOT_DELAY_STR
962 CONFIG_AUTOBOOT_STOP_STR
963 CONFIG_ZERO_BOOTDELAY_CHECK
964 CONFIG_RESET_TO_RETRY
968 Only needed when CONFIG_BOOTDELAY is enabled;
969 define a command string that is automatically executed
970 when no character is read on the console interface
971 within "Boot Delay" after reset.
974 This can be used to pass arguments to the bootm
975 command. The value of CONFIG_BOOTARGS goes into the
976 environment value "bootargs".
978 CONFIG_RAMBOOT and CONFIG_NFSBOOT
979 The value of these goes into the environment as
980 "ramboot" and "nfsboot" respectively, and can be used
981 as a convenience, when switching between booting from
985 CONFIG_BOOTCOUNT_LIMIT
986 Implements a mechanism for detecting a repeating reboot
988 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
991 If no softreset save registers are found on the hardware
992 "bootcount" is stored in the environment. To prevent a
993 saveenv on all reboots, the environment variable
994 "upgrade_available" is used. If "upgrade_available" is
995 0, "bootcount" is always 0, if "upgrade_available" is
996 1 "bootcount" is incremented in the environment.
997 So the Userspace Applikation must set the "upgrade_available"
998 and "bootcount" variable to 0, if a boot was successfully.
1000 - Pre-Boot Commands:
1003 When this option is #defined, the existence of the
1004 environment variable "preboot" will be checked
1005 immediately before starting the CONFIG_BOOTDELAY
1006 countdown and/or running the auto-boot command resp.
1007 entering interactive mode.
1009 This feature is especially useful when "preboot" is
1010 automatically generated or modified. For an example
1011 see the LWMON board specific code: here "preboot" is
1012 modified when the user holds down a certain
1013 combination of keys on the (special) keyboard when
1016 - Serial Download Echo Mode:
1018 If defined to 1, all characters received during a
1019 serial download (using the "loads" command) are
1020 echoed back. This might be needed by some terminal
1021 emulations (like "cu"), but may as well just take
1022 time on others. This setting #define's the initial
1023 value of the "loads_echo" environment variable.
1025 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
1026 CONFIG_KGDB_BAUDRATE
1027 Select one of the baudrates listed in
1028 CONFIG_SYS_BAUDRATE_TABLE, see below.
1030 - Monitor Functions:
1031 Monitor commands can be included or excluded
1032 from the build by using the #include files
1033 <config_cmd_all.h> and #undef'ing unwanted
1034 commands, or adding #define's for wanted commands.
1036 The default command configuration includes all commands
1037 except those marked below with a "*".
1039 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
1040 CONFIG_CMD_ASKENV * ask for env variable
1041 CONFIG_CMD_BDI bdinfo
1042 CONFIG_CMD_BEDBUG * Include BedBug Debugger
1043 CONFIG_CMD_BMP * BMP support
1044 CONFIG_CMD_BSP * Board specific commands
1045 CONFIG_CMD_BOOTD bootd
1046 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
1047 CONFIG_CMD_CACHE * icache, dcache
1048 CONFIG_CMD_CLK * clock command support
1049 CONFIG_CMD_CONSOLE coninfo
1050 CONFIG_CMD_CRC32 * crc32
1051 CONFIG_CMD_DATE * support for RTC, date/time...
1052 CONFIG_CMD_DHCP * DHCP support
1053 CONFIG_CMD_DIAG * Diagnostics
1054 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
1055 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
1056 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
1057 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
1058 CONFIG_CMD_DTT * Digital Therm and Thermostat
1059 CONFIG_CMD_ECHO echo arguments
1060 CONFIG_CMD_EDITENV edit env variable
1061 CONFIG_CMD_EEPROM * EEPROM read/write support
1062 CONFIG_CMD_ELF * bootelf, bootvx
1063 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
1064 CONFIG_CMD_ENV_FLAGS * display details about env flags
1065 CONFIG_CMD_ENV_EXISTS * check existence of env variable
1066 CONFIG_CMD_EXPORTENV * export the environment
1067 CONFIG_CMD_EXT2 * ext2 command support
1068 CONFIG_CMD_EXT4 * ext4 command support
1069 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
1070 that work for multiple fs types
1071 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
1072 CONFIG_CMD_SAVEENV saveenv
1073 CONFIG_CMD_FDC * Floppy Disk Support
1074 CONFIG_CMD_FAT * FAT command support
1075 CONFIG_CMD_FLASH flinfo, erase, protect
1076 CONFIG_CMD_FPGA FPGA device initialization support
1077 CONFIG_CMD_FUSE * Device fuse support
1078 CONFIG_CMD_GETTIME * Get time since boot
1079 CONFIG_CMD_GO * the 'go' command (exec code)
1080 CONFIG_CMD_GREPENV * search environment
1081 CONFIG_CMD_HASH * calculate hash / digest
1082 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
1083 CONFIG_CMD_I2C * I2C serial bus support
1084 CONFIG_CMD_IDE * IDE harddisk support
1085 CONFIG_CMD_IMI iminfo
1086 CONFIG_CMD_IMLS List all images found in NOR flash
1087 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1088 CONFIG_CMD_IMMAP * IMMR dump support
1089 CONFIG_CMD_IOTRACE * I/O tracing for debugging
1090 CONFIG_CMD_IMPORTENV * import an environment
1091 CONFIG_CMD_INI * import data from an ini file into the env
1092 CONFIG_CMD_IRQ * irqinfo
1093 CONFIG_CMD_ITEST Integer/string test of 2 values
1094 CONFIG_CMD_JFFS2 * JFFS2 Support
1095 CONFIG_CMD_KGDB * kgdb
1096 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1097 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1099 CONFIG_CMD_LOADB loadb
1100 CONFIG_CMD_LOADS loads
1101 CONFIG_CMD_MD5SUM * print md5 message digest
1102 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1103 CONFIG_CMD_MEMINFO * Display detailed memory information
1104 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1106 CONFIG_CMD_MEMTEST * mtest
1107 CONFIG_CMD_MISC Misc functions like sleep etc
1108 CONFIG_CMD_MMC * MMC memory mapped support
1109 CONFIG_CMD_MII * MII utility commands
1110 CONFIG_CMD_MTDPARTS * MTD partition support
1111 CONFIG_CMD_NAND * NAND support
1112 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1113 CONFIG_CMD_NFS NFS support
1114 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1115 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1116 CONFIG_CMD_PCI * pciinfo
1117 CONFIG_CMD_PCMCIA * PCMCIA support
1118 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1120 CONFIG_CMD_PORTIO * Port I/O
1121 CONFIG_CMD_READ * Read raw data from partition
1122 CONFIG_CMD_REGINFO * Register dump
1123 CONFIG_CMD_RUN run command in env variable
1124 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1125 CONFIG_CMD_SAVES * save S record dump
1126 CONFIG_CMD_SCSI * SCSI Support
1127 CONFIG_CMD_SDRAM * print SDRAM configuration information
1128 (requires CONFIG_CMD_I2C)
1129 CONFIG_CMD_SETGETDCR Support for DCR Register access
1131 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1132 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1133 (requires CONFIG_CMD_MEMORY)
1134 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1135 CONFIG_CMD_SOURCE "source" command Support
1136 CONFIG_CMD_SPI * SPI serial bus support
1137 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1138 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1139 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1140 CONFIG_CMD_TIMER * access to the system tick timer
1141 CONFIG_CMD_USB * USB support
1142 CONFIG_CMD_CDP * Cisco Discover Protocol support
1143 CONFIG_CMD_MFSL * Microblaze FSL support
1144 CONFIG_CMD_XIMG Load part of Multi Image
1145 CONFIG_CMD_UUID * Generate random UUID or GUID string
1147 EXAMPLE: If you want all functions except of network
1148 support you can write:
1150 #include "config_cmd_all.h"
1151 #undef CONFIG_CMD_NET
1154 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1156 Note: Don't enable the "icache" and "dcache" commands
1157 (configuration option CONFIG_CMD_CACHE) unless you know
1158 what you (and your U-Boot users) are doing. Data
1159 cache cannot be enabled on systems like the 8xx or
1160 8260 (where accesses to the IMMR region must be
1161 uncached), and it cannot be disabled on all other
1162 systems where we (mis-) use the data cache to hold an
1163 initial stack and some data.
1166 XXX - this list needs to get updated!
1168 - Regular expression support:
1170 If this variable is defined, U-Boot is linked against
1171 the SLRE (Super Light Regular Expression) library,
1172 which adds regex support to some commands, as for
1173 example "env grep" and "setexpr".
1177 If this variable is defined, U-Boot will use a device tree
1178 to configure its devices, instead of relying on statically
1179 compiled #defines in the board file. This option is
1180 experimental and only available on a few boards. The device
1181 tree is available in the global data as gd->fdt_blob.
1183 U-Boot needs to get its device tree from somewhere. This can
1184 be done using one of the two options below:
1187 If this variable is defined, U-Boot will embed a device tree
1188 binary in its image. This device tree file should be in the
1189 board directory and called <soc>-<board>.dts. The binary file
1190 is then picked up in board_init_f() and made available through
1191 the global data structure as gd->blob.
1194 If this variable is defined, U-Boot will build a device tree
1195 binary. It will be called u-boot.dtb. Architecture-specific
1196 code will locate it at run-time. Generally this works by:
1198 cat u-boot.bin u-boot.dtb >image.bin
1200 and in fact, U-Boot does this for you, creating a file called
1201 u-boot-dtb.bin which is useful in the common case. You can
1202 still use the individual files if you need something more
1207 If this variable is defined, it enables watchdog
1208 support for the SoC. There must be support in the SoC
1209 specific code for a watchdog. For the 8xx and 8260
1210 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1211 register. When supported for a specific SoC is
1212 available, then no further board specific code should
1213 be needed to use it.
1216 When using a watchdog circuitry external to the used
1217 SoC, then define this variable and provide board
1218 specific code for the "hw_watchdog_reset" function.
1220 CONFIG_AT91_HW_WDT_TIMEOUT
1221 specify the timeout in seconds. default 2 seconds.
1224 CONFIG_VERSION_VARIABLE
1225 If this variable is defined, an environment variable
1226 named "ver" is created by U-Boot showing the U-Boot
1227 version as printed by the "version" command.
1228 Any change to this variable will be reverted at the
1233 When CONFIG_CMD_DATE is selected, the type of the RTC
1234 has to be selected, too. Define exactly one of the
1237 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1238 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1239 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1240 CONFIG_RTC_MC146818 - use MC146818 RTC
1241 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1242 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1243 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1244 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1245 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1246 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1247 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1248 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1249 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1252 Note that if the RTC uses I2C, then the I2C interface
1253 must also be configured. See I2C Support, below.
1256 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1258 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1259 chip-ngpio pairs that tell the PCA953X driver the number of
1260 pins supported by a particular chip.
1262 Note that if the GPIO device uses I2C, then the I2C interface
1263 must also be configured. See I2C Support, below.
1266 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1267 accesses and can checksum them or write a list of them out
1268 to memory. See the 'iotrace' command for details. This is
1269 useful for testing device drivers since it can confirm that
1270 the driver behaves the same way before and after a code
1271 change. Currently this is supported on sandbox and arm. To
1272 add support for your architecture, add '#include <iotrace.h>'
1273 to the bottom of arch/<arch>/include/asm/io.h and test.
1275 Example output from the 'iotrace stats' command is below.
1276 Note that if the trace buffer is exhausted, the checksum will
1277 still continue to operate.
1280 Start: 10000000 (buffer start address)
1281 Size: 00010000 (buffer size)
1282 Offset: 00000120 (current buffer offset)
1283 Output: 10000120 (start + offset)
1284 Count: 00000018 (number of trace records)
1285 CRC32: 9526fb66 (CRC32 of all trace records)
1287 - Timestamp Support:
1289 When CONFIG_TIMESTAMP is selected, the timestamp
1290 (date and time) of an image is printed by image
1291 commands like bootm or iminfo. This option is
1292 automatically enabled when you select CONFIG_CMD_DATE .
1294 - Partition Labels (disklabels) Supported:
1295 Zero or more of the following:
1296 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1297 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1298 Intel architecture, USB sticks, etc.
1299 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1300 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1301 bootloader. Note 2TB partition limit; see
1303 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1305 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1306 CONFIG_CMD_SCSI) you must configure support for at
1307 least one non-MTD partition type as well.
1310 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1311 board configurations files but used nowhere!
1313 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1314 be performed by calling the function
1315 ide_set_reset(int reset)
1316 which has to be defined in a board specific file
1321 Set this to enable ATAPI support.
1326 Set this to enable support for disks larger than 137GB
1327 Also look at CONFIG_SYS_64BIT_LBA.
1328 Whithout these , LBA48 support uses 32bit variables and will 'only'
1329 support disks up to 2.1TB.
1331 CONFIG_SYS_64BIT_LBA:
1332 When enabled, makes the IDE subsystem use 64bit sector addresses.
1336 At the moment only there is only support for the
1337 SYM53C8XX SCSI controller; define
1338 CONFIG_SCSI_SYM53C8XX to enable it.
1340 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1341 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1342 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1343 maximum numbers of LUNs, SCSI ID's and target
1345 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1347 The environment variable 'scsidevs' is set to the number of
1348 SCSI devices found during the last scan.
1350 - NETWORK Support (PCI):
1352 Support for Intel 8254x/8257x gigabit chips.
1355 Utility code for direct access to the SPI bus on Intel 8257x.
1356 This does not do anything useful unless you set at least one
1357 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1359 CONFIG_E1000_SPI_GENERIC
1360 Allow generic access to the SPI bus on the Intel 8257x, for
1361 example with the "sspi" command.
1364 Management command for E1000 devices. When used on devices
1365 with SPI support you can reprogram the EEPROM from U-Boot.
1368 Support for Intel 82557/82559/82559ER chips.
1369 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1370 write routine for first time initialisation.
1373 Support for Digital 2114x chips.
1374 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1375 modem chip initialisation (KS8761/QS6611).
1378 Support for National dp83815 chips.
1381 Support for National dp8382[01] gigabit chips.
1383 - NETWORK Support (other):
1385 CONFIG_DRIVER_AT91EMAC
1386 Support for AT91RM9200 EMAC.
1389 Define this to use reduced MII inteface
1391 CONFIG_DRIVER_AT91EMAC_QUIET
1392 If this defined, the driver is quiet.
1393 The driver doen't show link status messages.
1395 CONFIG_CALXEDA_XGMAC
1396 Support for the Calxeda XGMAC device
1399 Support for SMSC's LAN91C96 chips.
1401 CONFIG_LAN91C96_BASE
1402 Define this to hold the physical address
1403 of the LAN91C96's I/O space
1405 CONFIG_LAN91C96_USE_32_BIT
1406 Define this to enable 32 bit addressing
1409 Support for SMSC's LAN91C111 chip
1411 CONFIG_SMC91111_BASE
1412 Define this to hold the physical address
1413 of the device (I/O space)
1415 CONFIG_SMC_USE_32_BIT
1416 Define this if data bus is 32 bits
1418 CONFIG_SMC_USE_IOFUNCS
1419 Define this to use i/o functions instead of macros
1420 (some hardware wont work with macros)
1422 CONFIG_DRIVER_TI_EMAC
1423 Support for davinci emac
1425 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1426 Define this if you have more then 3 PHYs.
1429 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1431 CONFIG_FTGMAC100_EGIGA
1432 Define this to use GE link update with gigabit PHY.
1433 Define this if FTGMAC100 is connected to gigabit PHY.
1434 If your system has 10/100 PHY only, it might not occur
1435 wrong behavior. Because PHY usually return timeout or
1436 useless data when polling gigabit status and gigabit
1437 control registers. This behavior won't affect the
1438 correctnessof 10/100 link speed update.
1441 Support for SMSC's LAN911x and LAN921x chips
1444 Define this to hold the physical address
1445 of the device (I/O space)
1447 CONFIG_SMC911X_32_BIT
1448 Define this if data bus is 32 bits
1450 CONFIG_SMC911X_16_BIT
1451 Define this if data bus is 16 bits. If your processor
1452 automatically converts one 32 bit word to two 16 bit
1453 words you may also try CONFIG_SMC911X_32_BIT.
1456 Support for Renesas on-chip Ethernet controller
1458 CONFIG_SH_ETHER_USE_PORT
1459 Define the number of ports to be used
1461 CONFIG_SH_ETHER_PHY_ADDR
1462 Define the ETH PHY's address
1464 CONFIG_SH_ETHER_CACHE_WRITEBACK
1465 If this option is set, the driver enables cache flush.
1469 Support for PWM modul on the imx6.
1473 Support TPM devices.
1475 CONFIG_TPM_TIS_INFINEON
1476 Support for Infineon i2c bus TPM devices. Only one device
1477 per system is supported at this time.
1479 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1480 Define the burst count bytes upper limit
1482 CONFIG_TPM_ATMEL_TWI
1483 Support for Atmel TWI TPM device. Requires I2C support.
1486 Support for generic parallel port TPM devices. Only one device
1487 per system is supported at this time.
1489 CONFIG_TPM_TIS_BASE_ADDRESS
1490 Base address where the generic TPM device is mapped
1491 to. Contemporary x86 systems usually map it at
1495 Add tpm monitor functions.
1496 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1497 provides monitor access to authorized functions.
1500 Define this to enable the TPM support library which provides
1501 functional interfaces to some TPM commands.
1502 Requires support for a TPM device.
1504 CONFIG_TPM_AUTH_SESSIONS
1505 Define this to enable authorized functions in the TPM library.
1506 Requires CONFIG_TPM and CONFIG_SHA1.
1509 At the moment only the UHCI host controller is
1510 supported (PIP405, MIP405, MPC5200); define
1511 CONFIG_USB_UHCI to enable it.
1512 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1513 and define CONFIG_USB_STORAGE to enable the USB
1516 Supported are USB Keyboards and USB Floppy drives
1518 MPC5200 USB requires additional defines:
1520 for 528 MHz Clock: 0x0001bbbb
1524 for differential drivers: 0x00001000
1525 for single ended drivers: 0x00005000
1526 for differential drivers on PSC3: 0x00000100
1527 for single ended drivers on PSC3: 0x00004100
1528 CONFIG_SYS_USB_EVENT_POLL
1529 May be defined to allow interrupt polling
1530 instead of using asynchronous interrupts
1532 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1533 txfilltuning field in the EHCI controller on reset.
1535 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1536 HW module registers.
1539 Define the below if you wish to use the USB console.
1540 Once firmware is rebuilt from a serial console issue the
1541 command "setenv stdin usbtty; setenv stdout usbtty" and
1542 attach your USB cable. The Unix command "dmesg" should print
1543 it has found a new device. The environment variable usbtty
1544 can be set to gserial or cdc_acm to enable your device to
1545 appear to a USB host as a Linux gserial device or a
1546 Common Device Class Abstract Control Model serial device.
1547 If you select usbtty = gserial you should be able to enumerate
1549 # modprobe usbserial vendor=0xVendorID product=0xProductID
1550 else if using cdc_acm, simply setting the environment
1551 variable usbtty to be cdc_acm should suffice. The following
1552 might be defined in YourBoardName.h
1555 Define this to build a UDC device
1558 Define this to have a tty type of device available to
1559 talk to the UDC device
1562 Define this to enable the high speed support for usb
1563 device and usbtty. If this feature is enabled, a routine
1564 int is_usbd_high_speed(void)
1565 also needs to be defined by the driver to dynamically poll
1566 whether the enumeration has succeded at high speed or full
1569 CONFIG_SYS_CONSOLE_IS_IN_ENV
1570 Define this if you want stdin, stdout &/or stderr to
1574 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1575 Derive USB clock from external clock "blah"
1576 - CONFIG_SYS_USB_EXTC_CLK 0x02
1578 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1579 Derive USB clock from brgclk
1580 - CONFIG_SYS_USB_BRG_CLK 0x04
1582 If you have a USB-IF assigned VendorID then you may wish to
1583 define your own vendor specific values either in BoardName.h
1584 or directly in usbd_vendor_info.h. If you don't define
1585 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1586 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1587 should pretend to be a Linux device to it's target host.
1589 CONFIG_USBD_MANUFACTURER
1590 Define this string as the name of your company for
1591 - CONFIG_USBD_MANUFACTURER "my company"
1593 CONFIG_USBD_PRODUCT_NAME
1594 Define this string as the name of your product
1595 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1597 CONFIG_USBD_VENDORID
1598 Define this as your assigned Vendor ID from the USB
1599 Implementors Forum. This *must* be a genuine Vendor ID
1600 to avoid polluting the USB namespace.
1601 - CONFIG_USBD_VENDORID 0xFFFF
1603 CONFIG_USBD_PRODUCTID
1604 Define this as the unique Product ID
1606 - CONFIG_USBD_PRODUCTID 0xFFFF
1608 - ULPI Layer Support:
1609 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1610 the generic ULPI layer. The generic layer accesses the ULPI PHY
1611 via the platform viewport, so you need both the genric layer and
1612 the viewport enabled. Currently only Chipidea/ARC based
1613 viewport is supported.
1614 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1615 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1616 If your ULPI phy needs a different reference clock than the
1617 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1618 the appropriate value in Hz.
1621 The MMC controller on the Intel PXA is supported. To
1622 enable this define CONFIG_MMC. The MMC can be
1623 accessed from the boot prompt by mapping the device
1624 to physical memory similar to flash. Command line is
1625 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1626 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1629 Support for Renesas on-chip MMCIF controller
1631 CONFIG_SH_MMCIF_ADDR
1632 Define the base address of MMCIF registers
1635 Define the clock frequency for MMCIF
1638 Enable the generic MMC driver
1640 CONFIG_SUPPORT_EMMC_BOOT
1641 Enable some additional features of the eMMC boot partitions.
1643 CONFIG_SUPPORT_EMMC_RPMB
1644 Enable the commands for reading, writing and programming the
1645 key for the Replay Protection Memory Block partition in eMMC.
1647 - USB Device Firmware Update (DFU) class support:
1648 CONFIG_USB_FUNCTION_DFU
1649 This enables the USB portion of the DFU USB class
1652 This enables the command "dfu" which is used to have
1653 U-Boot create a DFU class device via USB. This command
1654 requires that the "dfu_alt_info" environment variable be
1655 set and define the alt settings to expose to the host.
1658 This enables support for exposing (e)MMC devices via DFU.
1661 This enables support for exposing NAND devices via DFU.
1664 This enables support for exposing RAM via DFU.
1665 Note: DFU spec refer to non-volatile memory usage, but
1666 allow usages beyond the scope of spec - here RAM usage,
1667 one that would help mostly the developer.
1669 CONFIG_SYS_DFU_DATA_BUF_SIZE
1670 Dfu transfer uses a buffer before writing data to the
1671 raw storage device. Make the size (in bytes) of this buffer
1672 configurable. The size of this buffer is also configurable
1673 through the "dfu_bufsiz" environment variable.
1675 CONFIG_SYS_DFU_MAX_FILE_SIZE
1676 When updating files rather than the raw storage device,
1677 we use a static buffer to copy the file into and then write
1678 the buffer once we've been given the whole file. Define
1679 this to the maximum filesize (in bytes) for the buffer.
1680 Default is 4 MiB if undefined.
1682 DFU_DEFAULT_POLL_TIMEOUT
1683 Poll timeout [ms], is the timeout a device can send to the
1684 host. The host must wait for this timeout before sending
1685 a subsequent DFU_GET_STATUS request to the device.
1687 DFU_MANIFEST_POLL_TIMEOUT
1688 Poll timeout [ms], which the device sends to the host when
1689 entering dfuMANIFEST state. Host waits this timeout, before
1690 sending again an USB request to the device.
1692 - USB Device Android Fastboot support:
1693 CONFIG_USB_FUNCTION_FASTBOOT
1694 This enables the USB part of the fastboot gadget
1697 This enables the command "fastboot" which enables the Android
1698 fastboot mode for the platform's USB device. Fastboot is a USB
1699 protocol for downloading images, flashing and device control
1700 used on Android devices.
1701 See doc/README.android-fastboot for more information.
1703 CONFIG_ANDROID_BOOT_IMAGE
1704 This enables support for booting images which use the Android
1705 image format header.
1707 CONFIG_FASTBOOT_BUF_ADDR
1708 The fastboot protocol requires a large memory buffer for
1709 downloads. Define this to the starting RAM address to use for
1712 CONFIG_FASTBOOT_BUF_SIZE
1713 The fastboot protocol requires a large memory buffer for
1714 downloads. This buffer should be as large as possible for a
1715 platform. Define this to the size available RAM for fastboot.
1717 CONFIG_FASTBOOT_FLASH
1718 The fastboot protocol includes a "flash" command for writing
1719 the downloaded image to a non-volatile storage device. Define
1720 this to enable the "fastboot flash" command.
1722 CONFIG_FASTBOOT_FLASH_MMC_DEV
1723 The fastboot "flash" command requires additional information
1724 regarding the non-volatile storage device. Define this to
1725 the eMMC device that fastboot should use to store the image.
1727 CONFIG_FASTBOOT_GPT_NAME
1728 The fastboot "flash" command supports writing the downloaded
1729 image to the Protective MBR and the Primary GUID Partition
1730 Table. (Additionally, this downloaded image is post-processed
1731 to generate and write the Backup GUID Partition Table.)
1732 This occurs when the specified "partition name" on the
1733 "fastboot flash" command line matches this value.
1734 Default is GPT_ENTRY_NAME (currently "gpt") if undefined.
1736 - Journaling Flash filesystem support:
1737 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1738 CONFIG_JFFS2_NAND_DEV
1739 Define these for a default partition on a NAND device
1741 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1742 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1743 Define these for a default partition on a NOR device
1745 CONFIG_SYS_JFFS_CUSTOM_PART
1746 Define this to create an own partition. You have to provide a
1747 function struct part_info* jffs2_part_info(int part_num)
1749 If you define only one JFFS2 partition you may also want to
1750 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1751 to disable the command chpart. This is the default when you
1752 have not defined a custom partition
1754 - FAT(File Allocation Table) filesystem write function support:
1757 Define this to enable support for saving memory data as a
1758 file in FAT formatted partition.
1760 This will also enable the command "fatwrite" enabling the
1761 user to write files to FAT.
1763 CBFS (Coreboot Filesystem) support
1766 Define this to enable support for reading from a Coreboot
1767 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1770 - FAT(File Allocation Table) filesystem cluster size:
1771 CONFIG_FS_FAT_MAX_CLUSTSIZE
1773 Define the max cluster size for fat operations else
1774 a default value of 65536 will be defined.
1779 Define this to enable standard (PC-Style) keyboard
1783 Standard PC keyboard driver with US (is default) and
1784 GERMAN key layout (switch via environment 'keymap=de') support.
1785 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1786 for cfb_console. Supports cursor blinking.
1791 Define this to enable video support (for output to
1794 CONFIG_VIDEO_CT69000
1796 Enable Chips & Technologies 69000 Video chip
1798 CONFIG_VIDEO_SMI_LYNXEM
1799 Enable Silicon Motion SMI 712/710/810 Video chip. The
1800 video output is selected via environment 'videoout'
1801 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1804 For the CT69000 and SMI_LYNXEM drivers, videomode is
1805 selected via environment 'videomode'. Two different ways
1807 - "videomode=num" 'num' is a standard LiLo mode numbers.
1808 Following standard modes are supported (* is default):
1810 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1811 -------------+---------------------------------------------
1812 8 bits | 0x301* 0x303 0x305 0x161 0x307
1813 15 bits | 0x310 0x313 0x316 0x162 0x319
1814 16 bits | 0x311 0x314 0x317 0x163 0x31A
1815 24 bits | 0x312 0x315 0x318 ? 0x31B
1816 -------------+---------------------------------------------
1817 (i.e. setenv videomode 317; saveenv; reset;)
1819 - "videomode=bootargs" all the video parameters are parsed
1820 from the bootargs. (See drivers/video/videomodes.c)
1823 CONFIG_VIDEO_SED13806
1824 Enable Epson SED13806 driver. This driver supports 8bpp
1825 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1826 or CONFIG_VIDEO_SED13806_16BPP
1829 Enable the Freescale DIU video driver. Reference boards for
1830 SOCs that have a DIU should define this macro to enable DIU
1831 support, and should also define these other macros:
1837 CONFIG_VIDEO_SW_CURSOR
1838 CONFIG_VGA_AS_SINGLE_DEVICE
1840 CONFIG_VIDEO_BMP_LOGO
1842 The DIU driver will look for the 'video-mode' environment
1843 variable, and if defined, enable the DIU as a console during
1844 boot. See the documentation file README.video for a
1845 description of this variable.
1851 Define this to enable a custom keyboard support.
1852 This simply calls drv_keyboard_init() which must be
1853 defined in your board-specific files.
1854 The only board using this so far is RBC823.
1856 - LCD Support: CONFIG_LCD
1858 Define this to enable LCD support (for output to LCD
1859 display); also select one of the supported displays
1860 by defining one of these:
1864 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1866 CONFIG_NEC_NL6448AC33:
1868 NEC NL6448AC33-18. Active, color, single scan.
1870 CONFIG_NEC_NL6448BC20
1872 NEC NL6448BC20-08. 6.5", 640x480.
1873 Active, color, single scan.
1875 CONFIG_NEC_NL6448BC33_54
1877 NEC NL6448BC33-54. 10.4", 640x480.
1878 Active, color, single scan.
1882 Sharp 320x240. Active, color, single scan.
1883 It isn't 16x9, and I am not sure what it is.
1885 CONFIG_SHARP_LQ64D341
1887 Sharp LQ64D341 display, 640x480.
1888 Active, color, single scan.
1892 HLD1045 display, 640x480.
1893 Active, color, single scan.
1897 Optrex CBL50840-2 NF-FW 99 22 M5
1899 Hitachi LMG6912RPFC-00T
1903 320x240. Black & white.
1905 Normally display is black on white background; define
1906 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1908 CONFIG_LCD_ALIGNMENT
1910 Normally the LCD is page-aligned (typically 4KB). If this is
1911 defined then the LCD will be aligned to this value instead.
1912 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1913 here, since it is cheaper to change data cache settings on
1914 a per-section basis.
1916 CONFIG_CONSOLE_SCROLL_LINES
1918 When the console need to be scrolled, this is the number of
1919 lines to scroll by. It defaults to 1. Increasing this makes
1920 the console jump but can help speed up operation when scrolling
1925 Sometimes, for example if the display is mounted in portrait
1926 mode or even if it's mounted landscape but rotated by 180degree,
1927 we need to rotate our content of the display relative to the
1928 framebuffer, so that user can read the messages which are
1930 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1931 initialized with a given rotation from "vl_rot" out of
1932 "vidinfo_t" which is provided by the board specific code.
1933 The value for vl_rot is coded as following (matching to
1934 fbcon=rotate:<n> linux-kernel commandline):
1935 0 = no rotation respectively 0 degree
1936 1 = 90 degree rotation
1937 2 = 180 degree rotation
1938 3 = 270 degree rotation
1940 If CONFIG_LCD_ROTATION is not defined, the console will be
1941 initialized with 0degree rotation.
1945 Support drawing of RLE8-compressed bitmaps on the LCD.
1949 Enables an 'i2c edid' command which can read EDID
1950 information over I2C from an attached LCD display.
1952 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1954 If this option is set, the environment is checked for
1955 a variable "splashimage". If found, the usual display
1956 of logo, copyright and system information on the LCD
1957 is suppressed and the BMP image at the address
1958 specified in "splashimage" is loaded instead. The
1959 console is redirected to the "nulldev", too. This
1960 allows for a "silent" boot where a splash screen is
1961 loaded very quickly after power-on.
1963 CONFIG_SPLASHIMAGE_GUARD
1965 If this option is set, then U-Boot will prevent the environment
1966 variable "splashimage" from being set to a problematic address
1967 (see README.displaying-bmps).
1968 This option is useful for targets where, due to alignment
1969 restrictions, an improperly aligned BMP image will cause a data
1970 abort. If you think you will not have problems with unaligned
1971 accesses (for example because your toolchain prevents them)
1972 there is no need to set this option.
1974 CONFIG_SPLASH_SCREEN_ALIGN
1976 If this option is set the splash image can be freely positioned
1977 on the screen. Environment variable "splashpos" specifies the
1978 position as "x,y". If a positive number is given it is used as
1979 number of pixel from left/top. If a negative number is given it
1980 is used as number of pixel from right/bottom. You can also
1981 specify 'm' for centering the image.
1984 setenv splashpos m,m
1985 => image at center of screen
1987 setenv splashpos 30,20
1988 => image at x = 30 and y = 20
1990 setenv splashpos -10,m
1991 => vertically centered image
1992 at x = dspWidth - bmpWidth - 9
1994 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1996 If this option is set, additionally to standard BMP
1997 images, gzipped BMP images can be displayed via the
1998 splashscreen support or the bmp command.
2000 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
2002 If this option is set, 8-bit RLE compressed BMP images
2003 can be displayed via the splashscreen support or the
2006 - Do compressing for memory range:
2009 If this option is set, it would use zlib deflate method
2010 to compress the specified memory at its best effort.
2012 - Compression support:
2015 Enabled by default to support gzip compressed images.
2019 If this option is set, support for bzip2 compressed
2020 images is included. If not, only uncompressed and gzip
2021 compressed images are supported.
2023 NOTE: the bzip2 algorithm requires a lot of RAM, so
2024 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
2029 If this option is set, support for lzma compressed
2032 Note: The LZMA algorithm adds between 2 and 4KB of code and it
2033 requires an amount of dynamic memory that is given by the
2036 (1846 + 768 << (lc + lp)) * sizeof(uint16)
2038 Where lc and lp stand for, respectively, Literal context bits
2039 and Literal pos bits.
2041 This value is upper-bounded by 14MB in the worst case. Anyway,
2042 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
2043 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
2044 a very small buffer.
2046 Use the lzmainfo tool to determinate the lc and lp values and
2047 then calculate the amount of needed dynamic memory (ensuring
2048 the appropriate CONFIG_SYS_MALLOC_LEN value).
2052 If this option is set, support for LZO compressed images
2058 The address of PHY on MII bus.
2060 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
2062 The clock frequency of the MII bus
2066 If this option is set, support for speed/duplex
2067 detection of gigabit PHY is included.
2069 CONFIG_PHY_RESET_DELAY
2071 Some PHY like Intel LXT971A need extra delay after
2072 reset before any MII register access is possible.
2073 For such PHY, set this option to the usec delay
2074 required. (minimum 300usec for LXT971A)
2076 CONFIG_PHY_CMD_DELAY (ppc4xx)
2078 Some PHY like Intel LXT971A need extra delay after
2079 command issued before MII status register can be read
2084 Define a default value for the IP address to use for
2085 the default Ethernet interface, in case this is not
2086 determined through e.g. bootp.
2087 (Environment variable "ipaddr")
2089 - Server IP address:
2092 Defines a default value for the IP address of a TFTP
2093 server to contact when using the "tftboot" command.
2094 (Environment variable "serverip")
2096 CONFIG_KEEP_SERVERADDR
2098 Keeps the server's MAC address, in the env 'serveraddr'
2099 for passing to bootargs (like Linux's netconsole option)
2101 - Gateway IP address:
2104 Defines a default value for the IP address of the
2105 default router where packets to other networks are
2107 (Environment variable "gatewayip")
2112 Defines a default value for the subnet mask (or
2113 routing prefix) which is used to determine if an IP
2114 address belongs to the local subnet or needs to be
2115 forwarded through a router.
2116 (Environment variable "netmask")
2118 - Multicast TFTP Mode:
2121 Defines whether you want to support multicast TFTP as per
2122 rfc-2090; for example to work with atftp. Lets lots of targets
2123 tftp down the same boot image concurrently. Note: the Ethernet
2124 driver in use must provide a function: mcast() to join/leave a
2127 - BOOTP Recovery Mode:
2128 CONFIG_BOOTP_RANDOM_DELAY
2130 If you have many targets in a network that try to
2131 boot using BOOTP, you may want to avoid that all
2132 systems send out BOOTP requests at precisely the same
2133 moment (which would happen for instance at recovery
2134 from a power failure, when all systems will try to
2135 boot, thus flooding the BOOTP server. Defining
2136 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2137 inserted before sending out BOOTP requests. The
2138 following delays are inserted then:
2140 1st BOOTP request: delay 0 ... 1 sec
2141 2nd BOOTP request: delay 0 ... 2 sec
2142 3rd BOOTP request: delay 0 ... 4 sec
2144 BOOTP requests: delay 0 ... 8 sec
2146 CONFIG_BOOTP_ID_CACHE_SIZE
2148 BOOTP packets are uniquely identified using a 32-bit ID. The
2149 server will copy the ID from client requests to responses and
2150 U-Boot will use this to determine if it is the destination of
2151 an incoming response. Some servers will check that addresses
2152 aren't in use before handing them out (usually using an ARP
2153 ping) and therefore take up to a few hundred milliseconds to
2154 respond. Network congestion may also influence the time it
2155 takes for a response to make it back to the client. If that
2156 time is too long, U-Boot will retransmit requests. In order
2157 to allow earlier responses to still be accepted after these
2158 retransmissions, U-Boot's BOOTP client keeps a small cache of
2159 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2160 cache. The default is to keep IDs for up to four outstanding
2161 requests. Increasing this will allow U-Boot to accept offers
2162 from a BOOTP client in networks with unusually high latency.
2164 - DHCP Advanced Options:
2165 You can fine tune the DHCP functionality by defining
2166 CONFIG_BOOTP_* symbols:
2168 CONFIG_BOOTP_SUBNETMASK
2169 CONFIG_BOOTP_GATEWAY
2170 CONFIG_BOOTP_HOSTNAME
2171 CONFIG_BOOTP_NISDOMAIN
2172 CONFIG_BOOTP_BOOTPATH
2173 CONFIG_BOOTP_BOOTFILESIZE
2176 CONFIG_BOOTP_SEND_HOSTNAME
2177 CONFIG_BOOTP_NTPSERVER
2178 CONFIG_BOOTP_TIMEOFFSET
2179 CONFIG_BOOTP_VENDOREX
2180 CONFIG_BOOTP_MAY_FAIL
2182 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2183 environment variable, not the BOOTP server.
2185 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2186 after the configured retry count, the call will fail
2187 instead of starting over. This can be used to fail over
2188 to Link-local IP address configuration if the DHCP server
2191 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2192 serverip from a DHCP server, it is possible that more
2193 than one DNS serverip is offered to the client.
2194 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2195 serverip will be stored in the additional environment
2196 variable "dnsip2". The first DNS serverip is always
2197 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2200 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2201 to do a dynamic update of a DNS server. To do this, they
2202 need the hostname of the DHCP requester.
2203 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2204 of the "hostname" environment variable is passed as
2205 option 12 to the DHCP server.
2207 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2209 A 32bit value in microseconds for a delay between
2210 receiving a "DHCP Offer" and sending the "DHCP Request".
2211 This fixes a problem with certain DHCP servers that don't
2212 respond 100% of the time to a "DHCP request". E.g. On an
2213 AT91RM9200 processor running at 180MHz, this delay needed
2214 to be *at least* 15,000 usec before a Windows Server 2003
2215 DHCP server would reply 100% of the time. I recommend at
2216 least 50,000 usec to be safe. The alternative is to hope
2217 that one of the retries will be successful but note that
2218 the DHCP timeout and retry process takes a longer than
2221 - Link-local IP address negotiation:
2222 Negotiate with other link-local clients on the local network
2223 for an address that doesn't require explicit configuration.
2224 This is especially useful if a DHCP server cannot be guaranteed
2225 to exist in all environments that the device must operate.
2227 See doc/README.link-local for more information.
2230 CONFIG_CDP_DEVICE_ID
2232 The device id used in CDP trigger frames.
2234 CONFIG_CDP_DEVICE_ID_PREFIX
2236 A two character string which is prefixed to the MAC address
2241 A printf format string which contains the ascii name of
2242 the port. Normally is set to "eth%d" which sets
2243 eth0 for the first Ethernet, eth1 for the second etc.
2245 CONFIG_CDP_CAPABILITIES
2247 A 32bit integer which indicates the device capabilities;
2248 0x00000010 for a normal host which does not forwards.
2252 An ascii string containing the version of the software.
2256 An ascii string containing the name of the platform.
2260 A 32bit integer sent on the trigger.
2262 CONFIG_CDP_POWER_CONSUMPTION
2264 A 16bit integer containing the power consumption of the
2265 device in .1 of milliwatts.
2267 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2269 A byte containing the id of the VLAN.
2271 - Status LED: CONFIG_STATUS_LED
2273 Several configurations allow to display the current
2274 status using a LED. For instance, the LED will blink
2275 fast while running U-Boot code, stop blinking as
2276 soon as a reply to a BOOTP request was received, and
2277 start blinking slow once the Linux kernel is running
2278 (supported by a status LED driver in the Linux
2279 kernel). Defining CONFIG_STATUS_LED enables this
2285 The status LED can be connected to a GPIO pin.
2286 In such cases, the gpio_led driver can be used as a
2287 status LED backend implementation. Define CONFIG_GPIO_LED
2288 to include the gpio_led driver in the U-Boot binary.
2290 CONFIG_GPIO_LED_INVERTED_TABLE
2291 Some GPIO connected LEDs may have inverted polarity in which
2292 case the GPIO high value corresponds to LED off state and
2293 GPIO low value corresponds to LED on state.
2294 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2295 with a list of GPIO LEDs that have inverted polarity.
2297 - CAN Support: CONFIG_CAN_DRIVER
2299 Defining CONFIG_CAN_DRIVER enables CAN driver support
2300 on those systems that support this (optional)
2301 feature, like the TQM8xxL modules.
2303 - I2C Support: CONFIG_SYS_I2C
2305 This enable the NEW i2c subsystem, and will allow you to use
2306 i2c commands at the u-boot command line (as long as you set
2307 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2308 based realtime clock chips or other i2c devices. See
2309 common/cmd_i2c.c for a description of the command line
2312 ported i2c driver to the new framework:
2313 - drivers/i2c/soft_i2c.c:
2314 - activate first bus with CONFIG_SYS_I2C_SOFT define
2315 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2316 for defining speed and slave address
2317 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2318 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2319 for defining speed and slave address
2320 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2321 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2322 for defining speed and slave address
2323 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2324 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2325 for defining speed and slave address
2327 - drivers/i2c/fsl_i2c.c:
2328 - activate i2c driver with CONFIG_SYS_I2C_FSL
2329 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2330 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2331 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2333 - If your board supports a second fsl i2c bus, define
2334 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2335 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2336 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2339 - drivers/i2c/tegra_i2c.c:
2340 - activate this driver with CONFIG_SYS_I2C_TEGRA
2341 - This driver adds 4 i2c buses with a fix speed from
2342 100000 and the slave addr 0!
2344 - drivers/i2c/ppc4xx_i2c.c
2345 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2346 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2347 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2349 - drivers/i2c/i2c_mxc.c
2350 - activate this driver with CONFIG_SYS_I2C_MXC
2351 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2352 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2353 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2354 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2355 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2356 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2357 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2358 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2359 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2360 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2361 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2362 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2363 If those defines are not set, default value is 100000
2364 for speed, and 0 for slave.
2366 - drivers/i2c/rcar_i2c.c:
2367 - activate this driver with CONFIG_SYS_I2C_RCAR
2368 - This driver adds 4 i2c buses
2370 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2371 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2372 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2373 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2374 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2375 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2376 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2377 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2378 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2380 - drivers/i2c/sh_i2c.c:
2381 - activate this driver with CONFIG_SYS_I2C_SH
2382 - This driver adds from 2 to 5 i2c buses
2384 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2385 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2386 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2387 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2388 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2389 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2390 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2391 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2392 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2393 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2394 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2395 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2396 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2398 - drivers/i2c/omap24xx_i2c.c
2399 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2400 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2401 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2402 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2403 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2404 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2405 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2406 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2407 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2408 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2409 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2411 - drivers/i2c/zynq_i2c.c
2412 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2413 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2414 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2416 - drivers/i2c/s3c24x0_i2c.c:
2417 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2418 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2419 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2420 with a fix speed from 100000 and the slave addr 0!
2422 - drivers/i2c/ihs_i2c.c
2423 - activate this driver with CONFIG_SYS_I2C_IHS
2424 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2425 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2426 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2427 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2428 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2429 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2430 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2431 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2432 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2433 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2434 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2435 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2436 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2437 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2438 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2439 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2440 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2441 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2442 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2443 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2444 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2448 CONFIG_SYS_NUM_I2C_BUSES
2449 Hold the number of i2c buses you want to use. If you
2450 don't use/have i2c muxes on your i2c bus, this
2451 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2454 CONFIG_SYS_I2C_DIRECT_BUS
2455 define this, if you don't use i2c muxes on your hardware.
2456 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2459 CONFIG_SYS_I2C_MAX_HOPS
2460 define how many muxes are maximal consecutively connected
2461 on one i2c bus. If you not use i2c muxes, omit this
2464 CONFIG_SYS_I2C_BUSES
2465 hold a list of buses you want to use, only used if
2466 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2467 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2468 CONFIG_SYS_NUM_I2C_BUSES = 9:
2470 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2471 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2472 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2473 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2474 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2475 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2476 {1, {I2C_NULL_HOP}}, \
2477 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2478 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2482 bus 0 on adapter 0 without a mux
2483 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2484 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2485 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2486 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2487 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2488 bus 6 on adapter 1 without a mux
2489 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2490 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2492 If you do not have i2c muxes on your board, omit this define.
2494 - Legacy I2C Support: CONFIG_HARD_I2C
2496 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2497 provides the following compelling advantages:
2499 - more than one i2c adapter is usable
2500 - approved multibus support
2501 - better i2c mux support
2503 ** Please consider updating your I2C driver now. **
2505 These enable legacy I2C serial bus commands. Defining
2506 CONFIG_HARD_I2C will include the appropriate I2C driver
2507 for the selected CPU.
2509 This will allow you to use i2c commands at the u-boot
2510 command line (as long as you set CONFIG_CMD_I2C in
2511 CONFIG_COMMANDS) and communicate with i2c based realtime
2512 clock chips. See common/cmd_i2c.c for a description of the
2513 command line interface.
2515 CONFIG_HARD_I2C selects a hardware I2C controller.
2517 There are several other quantities that must also be
2518 defined when you define CONFIG_HARD_I2C.
2520 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2521 to be the frequency (in Hz) at which you wish your i2c bus
2522 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2523 the CPU's i2c node address).
2525 Now, the u-boot i2c code for the mpc8xx
2526 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2527 and so its address should therefore be cleared to 0 (See,
2528 eg, MPC823e User's Manual p.16-473). So, set
2529 CONFIG_SYS_I2C_SLAVE to 0.
2531 CONFIG_SYS_I2C_INIT_MPC5XXX
2533 When a board is reset during an i2c bus transfer
2534 chips might think that the current transfer is still
2535 in progress. Reset the slave devices by sending start
2536 commands until the slave device responds.
2538 That's all that's required for CONFIG_HARD_I2C.
2540 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2541 then the following macros need to be defined (examples are
2542 from include/configs/lwmon.h):
2546 (Optional). Any commands necessary to enable the I2C
2547 controller or configure ports.
2549 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2553 (Only for MPC8260 CPU). The I/O port to use (the code
2554 assumes both bits are on the same port). Valid values
2555 are 0..3 for ports A..D.
2559 The code necessary to make the I2C data line active
2560 (driven). If the data line is open collector, this
2563 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2567 The code necessary to make the I2C data line tri-stated
2568 (inactive). If the data line is open collector, this
2571 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2575 Code that returns true if the I2C data line is high,
2578 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2582 If <bit> is true, sets the I2C data line high. If it
2583 is false, it clears it (low).
2585 eg: #define I2C_SDA(bit) \
2586 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2587 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2591 If <bit> is true, sets the I2C clock line high. If it
2592 is false, it clears it (low).
2594 eg: #define I2C_SCL(bit) \
2595 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2596 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2600 This delay is invoked four times per clock cycle so this
2601 controls the rate of data transfer. The data rate thus
2602 is 1 / (I2C_DELAY * 4). Often defined to be something
2605 #define I2C_DELAY udelay(2)
2607 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2609 If your arch supports the generic GPIO framework (asm/gpio.h),
2610 then you may alternatively define the two GPIOs that are to be
2611 used as SCL / SDA. Any of the previous I2C_xxx macros will
2612 have GPIO-based defaults assigned to them as appropriate.
2614 You should define these to the GPIO value as given directly to
2615 the generic GPIO functions.
2617 CONFIG_SYS_I2C_INIT_BOARD
2619 When a board is reset during an i2c bus transfer
2620 chips might think that the current transfer is still
2621 in progress. On some boards it is possible to access
2622 the i2c SCLK line directly, either by using the
2623 processor pin as a GPIO or by having a second pin
2624 connected to the bus. If this option is defined a
2625 custom i2c_init_board() routine in boards/xxx/board.c
2626 is run early in the boot sequence.
2628 CONFIG_SYS_I2C_BOARD_LATE_INIT
2630 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2631 defined a custom i2c_board_late_init() routine in
2632 boards/xxx/board.c is run AFTER the operations in i2c_init()
2633 is completed. This callpoint can be used to unreset i2c bus
2634 using CPU i2c controller register accesses for CPUs whose i2c
2635 controller provide such a method. It is called at the end of
2636 i2c_init() to allow i2c_init operations to setup the i2c bus
2637 controller on the CPU (e.g. setting bus speed & slave address).
2639 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2641 This option enables configuration of bi_iic_fast[] flags
2642 in u-boot bd_info structure based on u-boot environment
2643 variable "i2cfast". (see also i2cfast)
2645 CONFIG_I2C_MULTI_BUS
2647 This option allows the use of multiple I2C buses, each of which
2648 must have a controller. At any point in time, only one bus is
2649 active. To switch to a different bus, use the 'i2c dev' command.
2650 Note that bus numbering is zero-based.
2652 CONFIG_SYS_I2C_NOPROBES
2654 This option specifies a list of I2C devices that will be skipped
2655 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2656 is set, specify a list of bus-device pairs. Otherwise, specify
2657 a 1D array of device addresses
2660 #undef CONFIG_I2C_MULTI_BUS
2661 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2663 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2665 #define CONFIG_I2C_MULTI_BUS
2666 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2668 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2670 CONFIG_SYS_SPD_BUS_NUM
2672 If defined, then this indicates the I2C bus number for DDR SPD.
2673 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2675 CONFIG_SYS_RTC_BUS_NUM
2677 If defined, then this indicates the I2C bus number for the RTC.
2678 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2680 CONFIG_SYS_DTT_BUS_NUM
2682 If defined, then this indicates the I2C bus number for the DTT.
2683 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2685 CONFIG_SYS_I2C_DTT_ADDR:
2687 If defined, specifies the I2C address of the DTT device.
2688 If not defined, then U-Boot uses predefined value for
2689 specified DTT device.
2691 CONFIG_SOFT_I2C_READ_REPEATED_START
2693 defining this will force the i2c_read() function in
2694 the soft_i2c driver to perform an I2C repeated start
2695 between writing the address pointer and reading the
2696 data. If this define is omitted the default behaviour
2697 of doing a stop-start sequence will be used. Most I2C
2698 devices can use either method, but some require one or
2701 - SPI Support: CONFIG_SPI
2703 Enables SPI driver (so far only tested with
2704 SPI EEPROM, also an instance works with Crystal A/D and
2705 D/As on the SACSng board)
2709 Enables the driver for SPI controller on SuperH. Currently
2710 only SH7757 is supported.
2714 Enables extended (16-bit) SPI EEPROM addressing.
2715 (symmetrical to CONFIG_I2C_X)
2719 Enables a software (bit-bang) SPI driver rather than
2720 using hardware support. This is a general purpose
2721 driver that only requires three general I/O port pins
2722 (two outputs, one input) to function. If this is
2723 defined, the board configuration must define several
2724 SPI configuration items (port pins to use, etc). For
2725 an example, see include/configs/sacsng.h.
2729 Enables a hardware SPI driver for general-purpose reads
2730 and writes. As with CONFIG_SOFT_SPI, the board configuration
2731 must define a list of chip-select function pointers.
2732 Currently supported on some MPC8xxx processors. For an
2733 example, see include/configs/mpc8349emds.h.
2737 Enables the driver for the SPI controllers on i.MX and MXC
2738 SoCs. Currently i.MX31/35/51 are supported.
2740 CONFIG_SYS_SPI_MXC_WAIT
2741 Timeout for waiting until spi transfer completed.
2742 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2744 - FPGA Support: CONFIG_FPGA
2746 Enables FPGA subsystem.
2748 CONFIG_FPGA_<vendor>
2750 Enables support for specific chip vendors.
2753 CONFIG_FPGA_<family>
2755 Enables support for FPGA family.
2756 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2760 Specify the number of FPGA devices to support.
2762 CONFIG_CMD_FPGA_LOADMK
2764 Enable support for fpga loadmk command
2766 CONFIG_CMD_FPGA_LOADP
2768 Enable support for fpga loadp command - load partial bitstream
2770 CONFIG_CMD_FPGA_LOADBP
2772 Enable support for fpga loadbp command - load partial bitstream
2775 CONFIG_SYS_FPGA_PROG_FEEDBACK
2777 Enable printing of hash marks during FPGA configuration.
2779 CONFIG_SYS_FPGA_CHECK_BUSY
2781 Enable checks on FPGA configuration interface busy
2782 status by the configuration function. This option
2783 will require a board or device specific function to
2788 If defined, a function that provides delays in the FPGA
2789 configuration driver.
2791 CONFIG_SYS_FPGA_CHECK_CTRLC
2792 Allow Control-C to interrupt FPGA configuration
2794 CONFIG_SYS_FPGA_CHECK_ERROR
2796 Check for configuration errors during FPGA bitfile
2797 loading. For example, abort during Virtex II
2798 configuration if the INIT_B line goes low (which
2799 indicated a CRC error).
2801 CONFIG_SYS_FPGA_WAIT_INIT
2803 Maximum time to wait for the INIT_B line to de-assert
2804 after PROB_B has been de-asserted during a Virtex II
2805 FPGA configuration sequence. The default time is 500
2808 CONFIG_SYS_FPGA_WAIT_BUSY
2810 Maximum time to wait for BUSY to de-assert during
2811 Virtex II FPGA configuration. The default is 5 ms.
2813 CONFIG_SYS_FPGA_WAIT_CONFIG
2815 Time to wait after FPGA configuration. The default is
2818 - Configuration Management:
2821 Some SoCs need special image types (e.g. U-Boot binary
2822 with a special header) as build targets. By defining
2823 CONFIG_BUILD_TARGET in the SoC / board header, this
2824 special image will be automatically built upon calling
2829 If defined, this string will be added to the U-Boot
2830 version information (U_BOOT_VERSION)
2832 - Vendor Parameter Protection:
2834 U-Boot considers the values of the environment
2835 variables "serial#" (Board Serial Number) and
2836 "ethaddr" (Ethernet Address) to be parameters that
2837 are set once by the board vendor / manufacturer, and
2838 protects these variables from casual modification by
2839 the user. Once set, these variables are read-only,
2840 and write or delete attempts are rejected. You can
2841 change this behaviour:
2843 If CONFIG_ENV_OVERWRITE is #defined in your config
2844 file, the write protection for vendor parameters is
2845 completely disabled. Anybody can change or delete
2848 Alternatively, if you define _both_ an ethaddr in the
2849 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2850 Ethernet address is installed in the environment,
2851 which can be changed exactly ONCE by the user. [The
2852 serial# is unaffected by this, i. e. it remains
2855 The same can be accomplished in a more flexible way
2856 for any variable by configuring the type of access
2857 to allow for those variables in the ".flags" variable
2858 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2863 Define this variable to enable the reservation of
2864 "protected RAM", i. e. RAM which is not overwritten
2865 by U-Boot. Define CONFIG_PRAM to hold the number of
2866 kB you want to reserve for pRAM. You can overwrite
2867 this default value by defining an environment
2868 variable "pram" to the number of kB you want to
2869 reserve. Note that the board info structure will
2870 still show the full amount of RAM. If pRAM is
2871 reserved, a new environment variable "mem" will
2872 automatically be defined to hold the amount of
2873 remaining RAM in a form that can be passed as boot
2874 argument to Linux, for instance like that:
2876 setenv bootargs ... mem=\${mem}
2879 This way you can tell Linux not to use this memory,
2880 either, which results in a memory region that will
2881 not be affected by reboots.
2883 *WARNING* If your board configuration uses automatic
2884 detection of the RAM size, you must make sure that
2885 this memory test is non-destructive. So far, the
2886 following board configurations are known to be
2889 IVMS8, IVML24, SPD8xx, TQM8xxL,
2890 HERMES, IP860, RPXlite, LWMON,
2893 - Access to physical memory region (> 4GB)
2894 Some basic support is provided for operations on memory not
2895 normally accessible to U-Boot - e.g. some architectures
2896 support access to more than 4GB of memory on 32-bit
2897 machines using physical address extension or similar.
2898 Define CONFIG_PHYSMEM to access this basic support, which
2899 currently only supports clearing the memory.
2904 Define this variable to stop the system in case of a
2905 fatal error, so that you have to reset it manually.
2906 This is probably NOT a good idea for an embedded
2907 system where you want the system to reboot
2908 automatically as fast as possible, but it may be
2909 useful during development since you can try to debug
2910 the conditions that lead to the situation.
2912 CONFIG_NET_RETRY_COUNT
2914 This variable defines the number of retries for
2915 network operations like ARP, RARP, TFTP, or BOOTP
2916 before giving up the operation. If not defined, a
2917 default value of 5 is used.
2921 Timeout waiting for an ARP reply in milliseconds.
2925 Timeout in milliseconds used in NFS protocol.
2926 If you encounter "ERROR: Cannot umount" in nfs command,
2927 try longer timeout such as
2928 #define CONFIG_NFS_TIMEOUT 10000UL
2930 - Command Interpreter:
2931 CONFIG_AUTO_COMPLETE
2933 Enable auto completion of commands using TAB.
2935 CONFIG_SYS_PROMPT_HUSH_PS2
2937 This defines the secondary prompt string, which is
2938 printed when the command interpreter needs more input
2939 to complete a command. Usually "> ".
2943 In the current implementation, the local variables
2944 space and global environment variables space are
2945 separated. Local variables are those you define by
2946 simply typing `name=value'. To access a local
2947 variable later on, you have write `$name' or
2948 `${name}'; to execute the contents of a variable
2949 directly type `$name' at the command prompt.
2951 Global environment variables are those you use
2952 setenv/printenv to work with. To run a command stored
2953 in such a variable, you need to use the run command,
2954 and you must not use the '$' sign to access them.
2956 To store commands and special characters in a
2957 variable, please use double quotation marks
2958 surrounding the whole text of the variable, instead
2959 of the backslashes before semicolons and special
2962 - Command Line Editing and History:
2963 CONFIG_CMDLINE_EDITING
2965 Enable editing and History functions for interactive
2966 command line input operations
2968 - Default Environment:
2969 CONFIG_EXTRA_ENV_SETTINGS
2971 Define this to contain any number of null terminated
2972 strings (variable = value pairs) that will be part of
2973 the default environment compiled into the boot image.
2975 For example, place something like this in your
2976 board's config file:
2978 #define CONFIG_EXTRA_ENV_SETTINGS \
2982 Warning: This method is based on knowledge about the
2983 internal format how the environment is stored by the
2984 U-Boot code. This is NOT an official, exported
2985 interface! Although it is unlikely that this format
2986 will change soon, there is no guarantee either.
2987 You better know what you are doing here.
2989 Note: overly (ab)use of the default environment is
2990 discouraged. Make sure to check other ways to preset
2991 the environment like the "source" command or the
2994 CONFIG_ENV_VARS_UBOOT_CONFIG
2996 Define this in order to add variables describing the
2997 U-Boot build configuration to the default environment.
2998 These will be named arch, cpu, board, vendor, and soc.
3000 Enabling this option will cause the following to be defined:
3008 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
3010 Define this in order to add variables describing certain
3011 run-time determined information about the hardware to the
3012 environment. These will be named board_name, board_rev.
3014 CONFIG_DELAY_ENVIRONMENT
3016 Normally the environment is loaded when the board is
3017 initialised so that it is available to U-Boot. This inhibits
3018 that so that the environment is not available until
3019 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
3020 this is instead controlled by the value of
3021 /config/load-environment.
3023 - Parallel Flash support:
3026 Traditionally U-boot was run on systems with parallel NOR
3027 flash. This option is used to disable support for parallel NOR
3028 flash. This option should be defined if the board does not have
3031 If this option is not defined one of the generic flash drivers
3032 (e.g. CONFIG_FLASH_CFI_DRIVER or CONFIG_ST_SMI) must be
3033 selected or the board must provide an implementation of the
3034 flash API (see include/flash.h).
3036 - DataFlash Support:
3037 CONFIG_HAS_DATAFLASH
3039 Defining this option enables DataFlash features and
3040 allows to read/write in Dataflash via the standard
3043 - Serial Flash support
3046 Defining this option enables SPI flash commands
3047 'sf probe/read/write/erase/update'.
3049 Usage requires an initial 'probe' to define the serial
3050 flash parameters, followed by read/write/erase/update
3053 The following defaults may be provided by the platform
3054 to handle the common case when only a single serial
3055 flash is present on the system.
3057 CONFIG_SF_DEFAULT_BUS Bus identifier
3058 CONFIG_SF_DEFAULT_CS Chip-select
3059 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
3060 CONFIG_SF_DEFAULT_SPEED in Hz
3064 Define this option to include a destructive SPI flash
3067 CONFIG_SF_DUAL_FLASH Dual flash memories
3069 Define this option to use dual flash support where two flash
3070 memories can be connected with a given cs line.
3071 Currently Xilinx Zynq qspi supports these type of connections.
3073 - SystemACE Support:
3076 Adding this option adds support for Xilinx SystemACE
3077 chips attached via some sort of local bus. The address
3078 of the chip must also be defined in the
3079 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
3081 #define CONFIG_SYSTEMACE
3082 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
3084 When SystemACE support is added, the "ace" device type
3085 becomes available to the fat commands, i.e. fatls.
3087 - TFTP Fixed UDP Port:
3090 If this is defined, the environment variable tftpsrcp
3091 is used to supply the TFTP UDP source port value.
3092 If tftpsrcp isn't defined, the normal pseudo-random port
3093 number generator is used.
3095 Also, the environment variable tftpdstp is used to supply
3096 the TFTP UDP destination port value. If tftpdstp isn't
3097 defined, the normal port 69 is used.
3099 The purpose for tftpsrcp is to allow a TFTP server to
3100 blindly start the TFTP transfer using the pre-configured
3101 target IP address and UDP port. This has the effect of
3102 "punching through" the (Windows XP) firewall, allowing
3103 the remainder of the TFTP transfer to proceed normally.
3104 A better solution is to properly configure the firewall,
3105 but sometimes that is not allowed.
3110 This enables a generic 'hash' command which can produce
3111 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3115 Enable the hash verify command (hash -v). This adds to code
3118 CONFIG_SHA1 - This option enables support of hashing using SHA1
3119 algorithm. The hash is calculated in software.
3120 CONFIG_SHA256 - This option enables support of hashing using
3121 SHA256 algorithm. The hash is calculated in software.
3122 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3123 for SHA1/SHA256 hashing.
3124 This affects the 'hash' command and also the
3125 hash_lookup_algo() function.
3126 CONFIG_SHA_PROG_HW_ACCEL - This option enables
3127 hardware-acceleration for SHA1/SHA256 progressive hashing.
3128 Data can be streamed in a block at a time and the hashing
3129 is performed in hardware.
3131 Note: There is also a sha1sum command, which should perhaps
3132 be deprecated in favour of 'hash sha1'.
3134 - Freescale i.MX specific commands:
3135 CONFIG_CMD_HDMIDETECT
3136 This enables 'hdmidet' command which returns true if an
3137 HDMI monitor is detected. This command is i.MX 6 specific.
3140 This enables the 'bmode' (bootmode) command for forcing
3141 a boot from specific media.
3143 This is useful for forcing the ROM's usb downloader to
3144 activate upon a watchdog reset which is nice when iterating
3145 on U-Boot. Using the reset button or running bmode normal
3146 will set it back to normal. This command currently
3147 supports i.MX53 and i.MX6.
3152 This enables the RSA algorithm used for FIT image verification
3153 in U-Boot. See doc/uImage.FIT/signature.txt for more information.
3155 The Modular Exponentiation algorithm in RSA is implemented using
3156 driver model. So CONFIG_DM needs to be enabled by default for this
3157 library to function.
3159 The signing part is build into mkimage regardless of this
3160 option. The software based modular exponentiation is built into
3161 mkimage irrespective of this option.
3163 - bootcount support:
3164 CONFIG_BOOTCOUNT_LIMIT
3166 This enables the bootcounter support, see:
3167 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3170 enable special bootcounter support on at91sam9xe based boards.
3172 enable special bootcounter support on blackfin based boards.
3174 enable special bootcounter support on da850 based boards.
3175 CONFIG_BOOTCOUNT_RAM
3176 enable support for the bootcounter in RAM
3177 CONFIG_BOOTCOUNT_I2C
3178 enable support for the bootcounter on an i2c (like RTC) device.
3179 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3180 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3182 CONFIG_BOOTCOUNT_ALEN = address len
3184 - Show boot progress:
3185 CONFIG_SHOW_BOOT_PROGRESS
3187 Defining this option allows to add some board-
3188 specific code (calling a user-provided function
3189 "show_boot_progress(int)") that enables you to show
3190 the system's boot progress on some display (for
3191 example, some LED's) on your board. At the moment,
3192 the following checkpoints are implemented:
3195 Legacy uImage format:
3198 1 common/cmd_bootm.c before attempting to boot an image
3199 -1 common/cmd_bootm.c Image header has bad magic number
3200 2 common/cmd_bootm.c Image header has correct magic number
3201 -2 common/cmd_bootm.c Image header has bad checksum
3202 3 common/cmd_bootm.c Image header has correct checksum
3203 -3 common/cmd_bootm.c Image data has bad checksum
3204 4 common/cmd_bootm.c Image data has correct checksum
3205 -4 common/cmd_bootm.c Image is for unsupported architecture
3206 5 common/cmd_bootm.c Architecture check OK
3207 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3208 6 common/cmd_bootm.c Image Type check OK
3209 -6 common/cmd_bootm.c gunzip uncompression error
3210 -7 common/cmd_bootm.c Unimplemented compression type
3211 7 common/cmd_bootm.c Uncompression OK
3212 8 common/cmd_bootm.c No uncompress/copy overwrite error
3213 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3215 9 common/image.c Start initial ramdisk verification
3216 -10 common/image.c Ramdisk header has bad magic number
3217 -11 common/image.c Ramdisk header has bad checksum
3218 10 common/image.c Ramdisk header is OK
3219 -12 common/image.c Ramdisk data has bad checksum
3220 11 common/image.c Ramdisk data has correct checksum
3221 12 common/image.c Ramdisk verification complete, start loading
3222 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3223 13 common/image.c Start multifile image verification
3224 14 common/image.c No initial ramdisk, no multifile, continue.
3226 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3228 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3229 -31 post/post.c POST test failed, detected by post_output_backlog()
3230 -32 post/post.c POST test failed, detected by post_run_single()
3232 34 common/cmd_doc.c before loading a Image from a DOC device
3233 -35 common/cmd_doc.c Bad usage of "doc" command
3234 35 common/cmd_doc.c correct usage of "doc" command
3235 -36 common/cmd_doc.c No boot device
3236 36 common/cmd_doc.c correct boot device
3237 -37 common/cmd_doc.c Unknown Chip ID on boot device
3238 37 common/cmd_doc.c correct chip ID found, device available
3239 -38 common/cmd_doc.c Read Error on boot device
3240 38 common/cmd_doc.c reading Image header from DOC device OK
3241 -39 common/cmd_doc.c Image header has bad magic number
3242 39 common/cmd_doc.c Image header has correct magic number
3243 -40 common/cmd_doc.c Error reading Image from DOC device
3244 40 common/cmd_doc.c Image header has correct magic number
3245 41 common/cmd_ide.c before loading a Image from a IDE device
3246 -42 common/cmd_ide.c Bad usage of "ide" command
3247 42 common/cmd_ide.c correct usage of "ide" command
3248 -43 common/cmd_ide.c No boot device
3249 43 common/cmd_ide.c boot device found
3250 -44 common/cmd_ide.c Device not available
3251 44 common/cmd_ide.c Device available
3252 -45 common/cmd_ide.c wrong partition selected
3253 45 common/cmd_ide.c partition selected
3254 -46 common/cmd_ide.c Unknown partition table
3255 46 common/cmd_ide.c valid partition table found
3256 -47 common/cmd_ide.c Invalid partition type
3257 47 common/cmd_ide.c correct partition type
3258 -48 common/cmd_ide.c Error reading Image Header on boot device
3259 48 common/cmd_ide.c reading Image Header from IDE device OK
3260 -49 common/cmd_ide.c Image header has bad magic number
3261 49 common/cmd_ide.c Image header has correct magic number
3262 -50 common/cmd_ide.c Image header has bad checksum
3263 50 common/cmd_ide.c Image header has correct checksum
3264 -51 common/cmd_ide.c Error reading Image from IDE device
3265 51 common/cmd_ide.c reading Image from IDE device OK
3266 52 common/cmd_nand.c before loading a Image from a NAND device
3267 -53 common/cmd_nand.c Bad usage of "nand" command
3268 53 common/cmd_nand.c correct usage of "nand" command
3269 -54 common/cmd_nand.c No boot device
3270 54 common/cmd_nand.c boot device found
3271 -55 common/cmd_nand.c Unknown Chip ID on boot device
3272 55 common/cmd_nand.c correct chip ID found, device available
3273 -56 common/cmd_nand.c Error reading Image Header on boot device
3274 56 common/cmd_nand.c reading Image Header from NAND device OK
3275 -57 common/cmd_nand.c Image header has bad magic number
3276 57 common/cmd_nand.c Image header has correct magic number
3277 -58 common/cmd_nand.c Error reading Image from NAND device
3278 58 common/cmd_nand.c reading Image from NAND device OK
3280 -60 common/env_common.c Environment has a bad CRC, using default
3282 64 net/eth.c starting with Ethernet configuration.
3283 -64 net/eth.c no Ethernet found.
3284 65 net/eth.c Ethernet found.
3286 -80 common/cmd_net.c usage wrong
3287 80 common/cmd_net.c before calling net_loop()
3288 -81 common/cmd_net.c some error in net_loop() occurred
3289 81 common/cmd_net.c net_loop() back without error
3290 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3291 82 common/cmd_net.c trying automatic boot
3292 83 common/cmd_net.c running "source" command
3293 -83 common/cmd_net.c some error in automatic boot or "source" command
3294 84 common/cmd_net.c end without errors
3299 100 common/cmd_bootm.c Kernel FIT Image has correct format
3300 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3301 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3302 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3303 102 common/cmd_bootm.c Kernel unit name specified
3304 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3305 103 common/cmd_bootm.c Found configuration node
3306 104 common/cmd_bootm.c Got kernel subimage node offset
3307 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3308 105 common/cmd_bootm.c Kernel subimage hash verification OK
3309 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3310 106 common/cmd_bootm.c Architecture check OK
3311 -106 common/cmd_bootm.c Kernel subimage has wrong type
3312 107 common/cmd_bootm.c Kernel subimage type OK
3313 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3314 108 common/cmd_bootm.c Got kernel subimage data/size
3315 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3316 -109 common/cmd_bootm.c Can't get kernel subimage type
3317 -110 common/cmd_bootm.c Can't get kernel subimage comp
3318 -111 common/cmd_bootm.c Can't get kernel subimage os
3319 -112 common/cmd_bootm.c Can't get kernel subimage load address
3320 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3322 120 common/image.c Start initial ramdisk verification
3323 -120 common/image.c Ramdisk FIT image has incorrect format
3324 121 common/image.c Ramdisk FIT image has correct format
3325 122 common/image.c No ramdisk subimage unit name, using configuration
3326 -122 common/image.c Can't get configuration for ramdisk subimage
3327 123 common/image.c Ramdisk unit name specified
3328 -124 common/image.c Can't get ramdisk subimage node offset
3329 125 common/image.c Got ramdisk subimage node offset
3330 -125 common/image.c Ramdisk subimage hash verification failed
3331 126 common/image.c Ramdisk subimage hash verification OK
3332 -126 common/image.c Ramdisk subimage for unsupported architecture
3333 127 common/image.c Architecture check OK
3334 -127 common/image.c Can't get ramdisk subimage data/size
3335 128 common/image.c Got ramdisk subimage data/size
3336 129 common/image.c Can't get ramdisk load address
3337 -129 common/image.c Got ramdisk load address
3339 -130 common/cmd_doc.c Incorrect FIT image format
3340 131 common/cmd_doc.c FIT image format OK
3342 -140 common/cmd_ide.c Incorrect FIT image format
3343 141 common/cmd_ide.c FIT image format OK
3345 -150 common/cmd_nand.c Incorrect FIT image format
3346 151 common/cmd_nand.c FIT image format OK
3348 - legacy image format:
3349 CONFIG_IMAGE_FORMAT_LEGACY
3350 enables the legacy image format support in U-Boot.
3353 enabled if CONFIG_FIT_SIGNATURE is not defined.
3355 CONFIG_DISABLE_IMAGE_LEGACY
3356 disable the legacy image format
3358 This define is introduced, as the legacy image format is
3359 enabled per default for backward compatibility.
3361 - FIT image support:
3363 Enable support for the FIT uImage format.
3365 CONFIG_FIT_BEST_MATCH
3366 When no configuration is explicitly selected, default to the
3367 one whose fdt's compatibility field best matches that of
3368 U-Boot itself. A match is considered "best" if it matches the
3369 most specific compatibility entry of U-Boot's fdt's root node.
3370 The order of entries in the configuration's fdt is ignored.
3372 CONFIG_FIT_SIGNATURE
3373 This option enables signature verification of FIT uImages,
3374 using a hash signed and verified using RSA. If
3375 CONFIG_SHA_PROG_HW_ACCEL is defined, i.e support for progressive
3376 hashing is available using hardware, RSA library will use it.
3377 See doc/uImage.FIT/signature.txt for more details.
3379 WARNING: When relying on signed FIT images with required
3380 signature check the legacy image format is default
3381 disabled. If a board need legacy image format support
3382 enable this through CONFIG_IMAGE_FORMAT_LEGACY
3384 CONFIG_FIT_DISABLE_SHA256
3385 Supporting SHA256 hashes has quite an impact on binary size.
3386 For constrained systems sha256 hash support can be disabled
3389 - Standalone program support:
3390 CONFIG_STANDALONE_LOAD_ADDR
3392 This option defines a board specific value for the
3393 address where standalone program gets loaded, thus
3394 overwriting the architecture dependent default
3397 - Frame Buffer Address:
3400 Define CONFIG_FB_ADDR if you want to use specific
3401 address for frame buffer. This is typically the case
3402 when using a graphics controller has separate video
3403 memory. U-Boot will then place the frame buffer at
3404 the given address instead of dynamically reserving it
3405 in system RAM by calling lcd_setmem(), which grabs
3406 the memory for the frame buffer depending on the
3407 configured panel size.
3409 Please see board_init_f function.
3411 - Automatic software updates via TFTP server
3413 CONFIG_UPDATE_TFTP_CNT_MAX
3414 CONFIG_UPDATE_TFTP_MSEC_MAX
3416 These options enable and control the auto-update feature;
3417 for a more detailed description refer to doc/README.update.
3419 - MTD Support (mtdparts command, UBI support)
3422 Adds the MTD device infrastructure from the Linux kernel.
3423 Needed for mtdparts command support.
3425 CONFIG_MTD_PARTITIONS
3427 Adds the MTD partitioning infrastructure from the Linux
3428 kernel. Needed for UBI support.
3433 Adds commands for interacting with MTD partitions formatted
3434 with the UBI flash translation layer
3436 Requires also defining CONFIG_RBTREE
3438 CONFIG_UBI_SILENCE_MSG
3440 Make the verbose messages from UBI stop printing. This leaves
3441 warnings and errors enabled.
3444 CONFIG_MTD_UBI_WL_THRESHOLD
3445 This parameter defines the maximum difference between the highest
3446 erase counter value and the lowest erase counter value of eraseblocks
3447 of UBI devices. When this threshold is exceeded, UBI starts performing
3448 wear leveling by means of moving data from eraseblock with low erase
3449 counter to eraseblocks with high erase counter.
3451 The default value should be OK for SLC NAND flashes, NOR flashes and
3452 other flashes which have eraseblock life-cycle 100000 or more.
3453 However, in case of MLC NAND flashes which typically have eraseblock
3454 life-cycle less than 10000, the threshold should be lessened (e.g.,
3455 to 128 or 256, although it does not have to be power of 2).
3459 CONFIG_MTD_UBI_BEB_LIMIT
3460 This option specifies the maximum bad physical eraseblocks UBI
3461 expects on the MTD device (per 1024 eraseblocks). If the
3462 underlying flash does not admit of bad eraseblocks (e.g. NOR
3463 flash), this value is ignored.
3465 NAND datasheets often specify the minimum and maximum NVM
3466 (Number of Valid Blocks) for the flashes' endurance lifetime.
3467 The maximum expected bad eraseblocks per 1024 eraseblocks
3468 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3469 which gives 20 for most NANDs (MaxNVB is basically the total
3470 count of eraseblocks on the chip).
3472 To put it differently, if this value is 20, UBI will try to
3473 reserve about 1.9% of physical eraseblocks for bad blocks
3474 handling. And that will be 1.9% of eraseblocks on the entire
3475 NAND chip, not just the MTD partition UBI attaches. This means
3476 that if you have, say, a NAND flash chip admits maximum 40 bad
3477 eraseblocks, and it is split on two MTD partitions of the same
3478 size, UBI will reserve 40 eraseblocks when attaching a
3483 CONFIG_MTD_UBI_FASTMAP
3484 Fastmap is a mechanism which allows attaching an UBI device
3485 in nearly constant time. Instead of scanning the whole MTD device it
3486 only has to locate a checkpoint (called fastmap) on the device.
3487 The on-flash fastmap contains all information needed to attach
3488 the device. Using fastmap makes only sense on large devices where
3489 attaching by scanning takes long. UBI will not automatically install
3490 a fastmap on old images, but you can set the UBI parameter
3491 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3492 that fastmap-enabled images are still usable with UBI implementations
3493 without fastmap support. On typical flash devices the whole fastmap
3494 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3496 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3497 Set this parameter to enable fastmap automatically on images
3501 CONFIG_MTD_UBI_FM_DEBUG
3502 Enable UBI fastmap debug
3508 Adds commands for interacting with UBI volumes formatted as
3509 UBIFS. UBIFS is read-only in u-boot.
3511 Requires UBI support as well as CONFIG_LZO
3513 CONFIG_UBIFS_SILENCE_MSG
3515 Make the verbose messages from UBIFS stop printing. This leaves
3516 warnings and errors enabled.
3520 Enable building of SPL globally.
3523 LDSCRIPT for linking the SPL binary.
3525 CONFIG_SPL_MAX_FOOTPRINT
3526 Maximum size in memory allocated to the SPL, BSS included.
3527 When defined, the linker checks that the actual memory
3528 used by SPL from _start to __bss_end does not exceed it.
3529 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3530 must not be both defined at the same time.
3533 Maximum size of the SPL image (text, data, rodata, and
3534 linker lists sections), BSS excluded.
3535 When defined, the linker checks that the actual size does
3538 CONFIG_SPL_TEXT_BASE
3539 TEXT_BASE for linking the SPL binary.
3541 CONFIG_SPL_RELOC_TEXT_BASE
3542 Address to relocate to. If unspecified, this is equal to
3543 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3545 CONFIG_SPL_BSS_START_ADDR
3546 Link address for the BSS within the SPL binary.
3548 CONFIG_SPL_BSS_MAX_SIZE
3549 Maximum size in memory allocated to the SPL BSS.
3550 When defined, the linker checks that the actual memory used
3551 by SPL from __bss_start to __bss_end does not exceed it.
3552 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3553 must not be both defined at the same time.
3556 Adress of the start of the stack SPL will use
3558 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3559 When defined, SPL will panic() if the image it has
3560 loaded does not have a signature.
3561 Defining this is useful when code which loads images
3562 in SPL cannot guarantee that absolutely all read errors
3564 An example is the LPC32XX MLC NAND driver, which will
3565 consider that a completely unreadable NAND block is bad,
3566 and thus should be skipped silently.
3568 CONFIG_SPL_RELOC_STACK
3569 Adress of the start of the stack SPL will use after
3570 relocation. If unspecified, this is equal to
3573 CONFIG_SYS_SPL_MALLOC_START
3574 Starting address of the malloc pool used in SPL.
3575 When this option is set the full malloc is used in SPL and
3576 it is set up by spl_init() and before that, the simple malloc()
3577 can be used if CONFIG_SYS_MALLOC_F is defined.
3579 CONFIG_SYS_SPL_MALLOC_SIZE
3580 The size of the malloc pool used in SPL.
3582 CONFIG_SPL_FRAMEWORK
3583 Enable the SPL framework under common/. This framework
3584 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3585 NAND loading of the Linux Kernel.
3588 Enable booting directly to an OS from SPL.
3589 See also: doc/README.falcon
3591 CONFIG_SPL_DISPLAY_PRINT
3592 For ARM, enable an optional function to print more information
3593 about the running system.
3595 CONFIG_SPL_INIT_MINIMAL
3596 Arch init code should be built for a very small image
3598 CONFIG_SPL_LIBCOMMON_SUPPORT
3599 Support for common/libcommon.o in SPL binary
3601 CONFIG_SPL_LIBDISK_SUPPORT
3602 Support for disk/libdisk.o in SPL binary
3604 CONFIG_SPL_I2C_SUPPORT
3605 Support for drivers/i2c/libi2c.o in SPL binary
3607 CONFIG_SPL_GPIO_SUPPORT
3608 Support for drivers/gpio/libgpio.o in SPL binary
3610 CONFIG_SPL_MMC_SUPPORT
3611 Support for drivers/mmc/libmmc.o in SPL binary
3613 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3614 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3615 Address and partition on the MMC to load U-Boot from
3616 when the MMC is being used in raw mode.
3618 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3619 Partition on the MMC to load U-Boot from when the MMC is being
3622 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3623 Sector to load kernel uImage from when MMC is being
3624 used in raw mode (for Falcon mode)
3626 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3627 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3628 Sector and number of sectors to load kernel argument
3629 parameters from when MMC is being used in raw mode
3632 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3633 Partition on the MMC to load U-Boot from when the MMC is being
3636 CONFIG_SPL_FAT_SUPPORT
3637 Support for fs/fat/libfat.o in SPL binary
3639 CONFIG_SPL_EXT_SUPPORT
3640 Support for EXT filesystem in SPL binary
3642 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3643 Filename to read to load U-Boot when reading from filesystem
3645 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3646 Filename to read to load kernel uImage when reading
3647 from filesystem (for Falcon mode)
3649 CONFIG_SPL_FS_LOAD_ARGS_NAME
3650 Filename to read to load kernel argument parameters
3651 when reading from filesystem (for Falcon mode)
3653 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3654 Set this for NAND SPL on PPC mpc83xx targets, so that
3655 start.S waits for the rest of the SPL to load before
3656 continuing (the hardware starts execution after just
3657 loading the first page rather than the full 4K).
3659 CONFIG_SPL_SKIP_RELOCATE
3660 Avoid SPL relocation
3662 CONFIG_SPL_NAND_BASE
3663 Include nand_base.c in the SPL. Requires
3664 CONFIG_SPL_NAND_DRIVERS.
3666 CONFIG_SPL_NAND_DRIVERS
3667 SPL uses normal NAND drivers, not minimal drivers.
3670 Include standard software ECC in the SPL
3672 CONFIG_SPL_NAND_SIMPLE
3673 Support for NAND boot using simple NAND drivers that
3674 expose the cmd_ctrl() interface.
3676 CONFIG_SPL_MTD_SUPPORT
3677 Support for the MTD subsystem within SPL. Useful for
3678 environment on NAND support within SPL.
3680 CONFIG_SPL_NAND_RAW_ONLY
3681 Support to boot only raw u-boot.bin images. Use this only
3682 if you need to save space.
3684 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT
3685 Set for the SPL on PPC mpc8xxx targets, support for
3686 drivers/ddr/fsl/libddr.o in SPL binary.
3688 CONFIG_SPL_COMMON_INIT_DDR
3689 Set for common ddr init with serial presence detect in
3692 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3693 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3694 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3695 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3696 CONFIG_SYS_NAND_ECCBYTES
3697 Defines the size and behavior of the NAND that SPL uses
3700 CONFIG_SPL_NAND_BOOT
3701 Add support NAND boot
3703 CONFIG_SYS_NAND_U_BOOT_OFFS
3704 Location in NAND to read U-Boot from
3706 CONFIG_SYS_NAND_U_BOOT_DST
3707 Location in memory to load U-Boot to
3709 CONFIG_SYS_NAND_U_BOOT_SIZE
3710 Size of image to load
3712 CONFIG_SYS_NAND_U_BOOT_START
3713 Entry point in loaded image to jump to
3715 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3716 Define this if you need to first read the OOB and then the
3717 data. This is used, for example, on davinci platforms.
3719 CONFIG_SPL_OMAP3_ID_NAND
3720 Support for an OMAP3-specific set of functions to return the
3721 ID and MFR of the first attached NAND chip, if present.
3723 CONFIG_SPL_SERIAL_SUPPORT
3724 Support for drivers/serial/libserial.o in SPL binary
3726 CONFIG_SPL_SPI_FLASH_SUPPORT
3727 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3729 CONFIG_SPL_SPI_SUPPORT
3730 Support for drivers/spi/libspi.o in SPL binary
3732 CONFIG_SPL_RAM_DEVICE
3733 Support for running image already present in ram, in SPL binary
3735 CONFIG_SPL_LIBGENERIC_SUPPORT
3736 Support for lib/libgeneric.o in SPL binary
3738 CONFIG_SPL_ENV_SUPPORT
3739 Support for the environment operating in SPL binary
3741 CONFIG_SPL_NET_SUPPORT
3742 Support for the net/libnet.o in SPL binary.
3743 It conflicts with SPL env from storage medium specified by
3744 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3747 Image offset to which the SPL should be padded before appending
3748 the SPL payload. By default, this is defined as
3749 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3750 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3751 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3754 Final target image containing SPL and payload. Some SPLs
3755 use an arch-specific makefile fragment instead, for
3756 example if more than one image needs to be produced.
3758 CONFIG_FIT_SPL_PRINT
3759 Printing information about a FIT image adds quite a bit of
3760 code to SPL. So this is normally disabled in SPL. Use this
3761 option to re-enable it. This will affect the output of the
3762 bootm command when booting a FIT image.
3766 Enable building of TPL globally.
3769 Image offset to which the TPL should be padded before appending
3770 the TPL payload. By default, this is defined as
3771 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3772 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3773 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3778 [so far only for SMDK2400 boards]
3780 - Modem support enable:
3781 CONFIG_MODEM_SUPPORT
3783 - RTS/CTS Flow control enable:
3786 - Modem debug support:
3787 CONFIG_MODEM_SUPPORT_DEBUG
3789 Enables debugging stuff (char screen[1024], dbg())
3790 for modem support. Useful only with BDI2000.
3792 - Interrupt support (PPC):
3794 There are common interrupt_init() and timer_interrupt()
3795 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3796 for CPU specific initialization. interrupt_init_cpu()
3797 should set decrementer_count to appropriate value. If
3798 CPU resets decrementer automatically after interrupt
3799 (ppc4xx) it should set decrementer_count to zero.
3800 timer_interrupt() calls timer_interrupt_cpu() for CPU
3801 specific handling. If board has watchdog / status_led
3802 / other_activity_monitor it works automatically from
3803 general timer_interrupt().
3807 In the target system modem support is enabled when a
3808 specific key (key combination) is pressed during
3809 power-on. Otherwise U-Boot will boot normally
3810 (autoboot). The key_pressed() function is called from
3811 board_init(). Currently key_pressed() is a dummy
3812 function, returning 1 and thus enabling modem
3815 If there are no modem init strings in the
3816 environment, U-Boot proceed to autoboot; the
3817 previous output (banner, info printfs) will be
3820 See also: doc/README.Modem
3822 Board initialization settings:
3823 ------------------------------
3825 During Initialization u-boot calls a number of board specific functions
3826 to allow the preparation of board specific prerequisites, e.g. pin setup
3827 before drivers are initialized. To enable these callbacks the
3828 following configuration macros have to be defined. Currently this is
3829 architecture specific, so please check arch/your_architecture/lib/board.c
3830 typically in board_init_f() and board_init_r().
3832 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3833 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3834 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3835 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3837 Configuration Settings:
3838 -----------------------
3840 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3841 Optionally it can be defined to support 64-bit memory commands.
3843 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3844 undefine this when you're short of memory.
3846 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3847 width of the commands listed in the 'help' command output.
3849 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3850 prompt for user input.
3852 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3854 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3856 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3858 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3859 the application (usually a Linux kernel) when it is
3862 - CONFIG_SYS_BAUDRATE_TABLE:
3863 List of legal baudrate settings for this board.
3865 - CONFIG_SYS_CONSOLE_INFO_QUIET
3866 Suppress display of console information at boot.
3868 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3869 If the board specific function
3870 extern int overwrite_console (void);
3871 returns 1, the stdin, stderr and stdout are switched to the
3872 serial port, else the settings in the environment are used.
3874 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3875 Enable the call to overwrite_console().
3877 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3878 Enable overwrite of previous console environment settings.
3880 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3881 Begin and End addresses of the area used by the
3884 - CONFIG_SYS_ALT_MEMTEST:
3885 Enable an alternate, more extensive memory test.
3887 - CONFIG_SYS_MEMTEST_SCRATCH:
3888 Scratch address used by the alternate memory test
3889 You only need to set this if address zero isn't writeable
3891 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3892 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3893 this specified memory area will get subtracted from the top
3894 (end) of RAM and won't get "touched" at all by U-Boot. By
3895 fixing up gd->ram_size the Linux kernel should gets passed
3896 the now "corrected" memory size and won't touch it either.
3897 This should work for arch/ppc and arch/powerpc. Only Linux
3898 board ports in arch/powerpc with bootwrapper support that
3899 recalculate the memory size from the SDRAM controller setup
3900 will have to get fixed in Linux additionally.
3902 This option can be used as a workaround for the 440EPx/GRx
3903 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3906 WARNING: Please make sure that this value is a multiple of
3907 the Linux page size (normally 4k). If this is not the case,
3908 then the end address of the Linux memory will be located at a
3909 non page size aligned address and this could cause major
3912 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3913 Enable temporary baudrate change while serial download
3915 - CONFIG_SYS_SDRAM_BASE:
3916 Physical start address of SDRAM. _Must_ be 0 here.
3918 - CONFIG_SYS_MBIO_BASE:
3919 Physical start address of Motherboard I/O (if using a
3922 - CONFIG_SYS_FLASH_BASE:
3923 Physical start address of Flash memory.
3925 - CONFIG_SYS_MONITOR_BASE:
3926 Physical start address of boot monitor code (set by
3927 make config files to be same as the text base address
3928 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3929 CONFIG_SYS_FLASH_BASE when booting from flash.
3931 - CONFIG_SYS_MONITOR_LEN:
3932 Size of memory reserved for monitor code, used to
3933 determine _at_compile_time_ (!) if the environment is
3934 embedded within the U-Boot image, or in a separate
3937 - CONFIG_SYS_MALLOC_LEN:
3938 Size of DRAM reserved for malloc() use.
3940 - CONFIG_SYS_MALLOC_F_LEN
3941 Size of the malloc() pool for use before relocation. If
3942 this is defined, then a very simple malloc() implementation
3943 will become available before relocation. The address is just
3944 below the global data, and the stack is moved down to make
3947 This feature allocates regions with increasing addresses
3948 within the region. calloc() is supported, but realloc()
3949 is not available. free() is supported but does nothing.
3950 The memory will be freed (or in fact just forgotten) when
3951 U-Boot relocates itself.
3953 Pre-relocation malloc() is only supported on ARM and sandbox
3954 at present but is fairly easy to enable for other archs.
3956 - CONFIG_SYS_MALLOC_SIMPLE
3957 Provides a simple and small malloc() and calloc() for those
3958 boards which do not use the full malloc in SPL (which is
3959 enabled with CONFIG_SYS_SPL_MALLOC_START).
3961 - CONFIG_SYS_NONCACHED_MEMORY:
3962 Size of non-cached memory area. This area of memory will be
3963 typically located right below the malloc() area and mapped
3964 uncached in the MMU. This is useful for drivers that would
3965 otherwise require a lot of explicit cache maintenance. For
3966 some drivers it's also impossible to properly maintain the
3967 cache. For example if the regions that need to be flushed
3968 are not a multiple of the cache-line size, *and* padding
3969 cannot be allocated between the regions to align them (i.e.
3970 if the HW requires a contiguous array of regions, and the
3971 size of each region is not cache-aligned), then a flush of
3972 one region may result in overwriting data that hardware has
3973 written to another region in the same cache-line. This can
3974 happen for example in network drivers where descriptors for
3975 buffers are typically smaller than the CPU cache-line (e.g.
3976 16 bytes vs. 32 or 64 bytes).
3978 Non-cached memory is only supported on 32-bit ARM at present.
3980 - CONFIG_SYS_BOOTM_LEN:
3981 Normally compressed uImages are limited to an
3982 uncompressed size of 8 MBytes. If this is not enough,
3983 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3984 to adjust this setting to your needs.
3986 - CONFIG_SYS_BOOTMAPSZ:
3987 Maximum size of memory mapped by the startup code of
3988 the Linux kernel; all data that must be processed by
3989 the Linux kernel (bd_info, boot arguments, FDT blob if
3990 used) must be put below this limit, unless "bootm_low"
3991 environment variable is defined and non-zero. In such case
3992 all data for the Linux kernel must be between "bootm_low"
3993 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3994 variable "bootm_mapsize" will override the value of
3995 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3996 then the value in "bootm_size" will be used instead.
3998 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3999 Enable initrd_high functionality. If defined then the
4000 initrd_high feature is enabled and the bootm ramdisk subcommand
4003 - CONFIG_SYS_BOOT_GET_CMDLINE:
4004 Enables allocating and saving kernel cmdline in space between
4005 "bootm_low" and "bootm_low" + BOOTMAPSZ.
4007 - CONFIG_SYS_BOOT_GET_KBD:
4008 Enables allocating and saving a kernel copy of the bd_info in
4009 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
4011 - CONFIG_SYS_MAX_FLASH_BANKS:
4012 Max number of Flash memory banks
4014 - CONFIG_SYS_MAX_FLASH_SECT:
4015 Max number of sectors on a Flash chip
4017 - CONFIG_SYS_FLASH_ERASE_TOUT:
4018 Timeout for Flash erase operations (in ms)
4020 - CONFIG_SYS_FLASH_WRITE_TOUT:
4021 Timeout for Flash write operations (in ms)
4023 - CONFIG_SYS_FLASH_LOCK_TOUT
4024 Timeout for Flash set sector lock bit operation (in ms)
4026 - CONFIG_SYS_FLASH_UNLOCK_TOUT
4027 Timeout for Flash clear lock bits operation (in ms)
4029 - CONFIG_SYS_FLASH_PROTECTION
4030 If defined, hardware flash sectors protection is used
4031 instead of U-Boot software protection.
4033 - CONFIG_SYS_DIRECT_FLASH_TFTP:
4035 Enable TFTP transfers directly to flash memory;
4036 without this option such a download has to be
4037 performed in two steps: (1) download to RAM, and (2)
4038 copy from RAM to flash.
4040 The two-step approach is usually more reliable, since
4041 you can check if the download worked before you erase
4042 the flash, but in some situations (when system RAM is
4043 too limited to allow for a temporary copy of the
4044 downloaded image) this option may be very useful.
4046 - CONFIG_SYS_FLASH_CFI:
4047 Define if the flash driver uses extra elements in the
4048 common flash structure for storing flash geometry.
4050 - CONFIG_FLASH_CFI_DRIVER
4051 This option also enables the building of the cfi_flash driver
4052 in the drivers directory
4054 - CONFIG_FLASH_CFI_MTD
4055 This option enables the building of the cfi_mtd driver
4056 in the drivers directory. The driver exports CFI flash
4059 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
4060 Use buffered writes to flash.
4062 - CONFIG_FLASH_SPANSION_S29WS_N
4063 s29ws-n MirrorBit flash has non-standard addresses for buffered
4066 - CONFIG_SYS_FLASH_QUIET_TEST
4067 If this option is defined, the common CFI flash doesn't
4068 print it's warning upon not recognized FLASH banks. This
4069 is useful, if some of the configured banks are only
4070 optionally available.
4072 - CONFIG_FLASH_SHOW_PROGRESS
4073 If defined (must be an integer), print out countdown
4074 digits and dots. Recommended value: 45 (9..1) for 80
4075 column displays, 15 (3..1) for 40 column displays.
4077 - CONFIG_FLASH_VERIFY
4078 If defined, the content of the flash (destination) is compared
4079 against the source after the write operation. An error message
4080 will be printed when the contents are not identical.
4081 Please note that this option is useless in nearly all cases,
4082 since such flash programming errors usually are detected earlier
4083 while unprotecting/erasing/programming. Please only enable
4084 this option if you really know what you are doing.
4086 - CONFIG_SYS_RX_ETH_BUFFER:
4087 Defines the number of Ethernet receive buffers. On some
4088 Ethernet controllers it is recommended to set this value
4089 to 8 or even higher (EEPRO100 or 405 EMAC), since all
4090 buffers can be full shortly after enabling the interface
4091 on high Ethernet traffic.
4092 Defaults to 4 if not defined.
4094 - CONFIG_ENV_MAX_ENTRIES
4096 Maximum number of entries in the hash table that is used
4097 internally to store the environment settings. The default
4098 setting is supposed to be generous and should work in most
4099 cases. This setting can be used to tune behaviour; see
4100 lib/hashtable.c for details.
4102 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4103 - CONFIG_ENV_FLAGS_LIST_STATIC
4104 Enable validation of the values given to environment variables when
4105 calling env set. Variables can be restricted to only decimal,
4106 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
4107 the variables can also be restricted to IP address or MAC address.
4109 The format of the list is:
4110 type_attribute = [s|d|x|b|i|m]
4111 access_attribute = [a|r|o|c]
4112 attributes = type_attribute[access_attribute]
4113 entry = variable_name[:attributes]
4116 The type attributes are:
4117 s - String (default)
4120 b - Boolean ([1yYtT|0nNfF])
4124 The access attributes are:
4130 - CONFIG_ENV_FLAGS_LIST_DEFAULT
4131 Define this to a list (string) to define the ".flags"
4132 environment variable in the default or embedded environment.
4134 - CONFIG_ENV_FLAGS_LIST_STATIC
4135 Define this to a list (string) to define validation that
4136 should be done if an entry is not found in the ".flags"
4137 environment variable. To override a setting in the static
4138 list, simply add an entry for the same variable name to the
4141 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4142 regular expression. This allows multiple variables to define the same
4143 flags without explicitly listing them for each variable.
4145 - CONFIG_ENV_ACCESS_IGNORE_FORCE
4146 If defined, don't allow the -f switch to env set override variable
4149 - CONFIG_SYS_GENERIC_BOARD
4150 This selects the architecture-generic board system instead of the
4151 architecture-specific board files. It is intended to move boards
4152 to this new framework over time. Defining this will disable the
4153 arch/foo/lib/board.c file and use common/board_f.c and
4154 common/board_r.c instead. To use this option your architecture
4155 must support it (i.e. must select HAVE_GENERIC_BOARD in arch/Kconfig).
4156 If you find problems enabling this option on your board please report
4157 the problem and send patches!
4159 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
4160 This is set by OMAP boards for the max time that reset should
4161 be asserted. See doc/README.omap-reset-time for details on how
4162 the value can be calculated on a given board.
4165 If stdint.h is available with your toolchain you can define this
4166 option to enable it. You can provide option 'USE_STDINT=1' when
4167 building U-Boot to enable this.
4169 The following definitions that deal with the placement and management
4170 of environment data (variable area); in general, we support the
4171 following configurations:
4173 - CONFIG_BUILD_ENVCRC:
4175 Builds up envcrc with the target environment so that external utils
4176 may easily extract it and embed it in final U-Boot images.
4178 - CONFIG_ENV_IS_IN_FLASH:
4180 Define this if the environment is in flash memory.
4182 a) The environment occupies one whole flash sector, which is
4183 "embedded" in the text segment with the U-Boot code. This
4184 happens usually with "bottom boot sector" or "top boot
4185 sector" type flash chips, which have several smaller
4186 sectors at the start or the end. For instance, such a
4187 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4188 such a case you would place the environment in one of the
4189 4 kB sectors - with U-Boot code before and after it. With
4190 "top boot sector" type flash chips, you would put the
4191 environment in one of the last sectors, leaving a gap
4192 between U-Boot and the environment.
4194 - CONFIG_ENV_OFFSET:
4196 Offset of environment data (variable area) to the
4197 beginning of flash memory; for instance, with bottom boot
4198 type flash chips the second sector can be used: the offset
4199 for this sector is given here.
4201 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4205 This is just another way to specify the start address of
4206 the flash sector containing the environment (instead of
4209 - CONFIG_ENV_SECT_SIZE:
4211 Size of the sector containing the environment.
4214 b) Sometimes flash chips have few, equal sized, BIG sectors.
4215 In such a case you don't want to spend a whole sector for
4220 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4221 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4222 of this flash sector for the environment. This saves
4223 memory for the RAM copy of the environment.
4225 It may also save flash memory if you decide to use this
4226 when your environment is "embedded" within U-Boot code,
4227 since then the remainder of the flash sector could be used
4228 for U-Boot code. It should be pointed out that this is
4229 STRONGLY DISCOURAGED from a robustness point of view:
4230 updating the environment in flash makes it always
4231 necessary to erase the WHOLE sector. If something goes
4232 wrong before the contents has been restored from a copy in
4233 RAM, your target system will be dead.
4235 - CONFIG_ENV_ADDR_REDUND
4236 CONFIG_ENV_SIZE_REDUND
4238 These settings describe a second storage area used to hold
4239 a redundant copy of the environment data, so that there is
4240 a valid backup copy in case there is a power failure during
4241 a "saveenv" operation.
4243 BE CAREFUL! Any changes to the flash layout, and some changes to the
4244 source code will make it necessary to adapt <board>/u-boot.lds*
4248 - CONFIG_ENV_IS_IN_NVRAM:
4250 Define this if you have some non-volatile memory device
4251 (NVRAM, battery buffered SRAM) which you want to use for the
4257 These two #defines are used to determine the memory area you
4258 want to use for environment. It is assumed that this memory
4259 can just be read and written to, without any special
4262 BE CAREFUL! The first access to the environment happens quite early
4263 in U-Boot initialization (when we try to get the setting of for the
4264 console baudrate). You *MUST* have mapped your NVRAM area then, or
4267 Please note that even with NVRAM we still use a copy of the
4268 environment in RAM: we could work on NVRAM directly, but we want to
4269 keep settings there always unmodified except somebody uses "saveenv"
4270 to save the current settings.
4273 - CONFIG_ENV_IS_IN_EEPROM:
4275 Use this if you have an EEPROM or similar serial access
4276 device and a driver for it.
4278 - CONFIG_ENV_OFFSET:
4281 These two #defines specify the offset and size of the
4282 environment area within the total memory of your EEPROM.
4284 - CONFIG_SYS_I2C_EEPROM_ADDR:
4285 If defined, specified the chip address of the EEPROM device.
4286 The default address is zero.
4288 - CONFIG_SYS_I2C_EEPROM_BUS:
4289 If defined, specified the i2c bus of the EEPROM device.
4291 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4292 If defined, the number of bits used to address bytes in a
4293 single page in the EEPROM device. A 64 byte page, for example
4294 would require six bits.
4296 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4297 If defined, the number of milliseconds to delay between
4298 page writes. The default is zero milliseconds.
4300 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4301 The length in bytes of the EEPROM memory array address. Note
4302 that this is NOT the chip address length!
4304 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4305 EEPROM chips that implement "address overflow" are ones
4306 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4307 address and the extra bits end up in the "chip address" bit
4308 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4311 Note that we consider the length of the address field to
4312 still be one byte because the extra address bits are hidden
4313 in the chip address.
4315 - CONFIG_SYS_EEPROM_SIZE:
4316 The size in bytes of the EEPROM device.
4318 - CONFIG_ENV_EEPROM_IS_ON_I2C
4319 define this, if you have I2C and SPI activated, and your
4320 EEPROM, which holds the environment, is on the I2C bus.
4322 - CONFIG_I2C_ENV_EEPROM_BUS
4323 if you have an Environment on an EEPROM reached over
4324 I2C muxes, you can define here, how to reach this
4325 EEPROM. For example:
4327 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4329 EEPROM which holds the environment, is reached over
4330 a pca9547 i2c mux with address 0x70, channel 3.
4332 - CONFIG_ENV_IS_IN_DATAFLASH:
4334 Define this if you have a DataFlash memory device which you
4335 want to use for the environment.
4337 - CONFIG_ENV_OFFSET:
4341 These three #defines specify the offset and size of the
4342 environment area within the total memory of your DataFlash placed
4343 at the specified address.
4345 - CONFIG_ENV_IS_IN_SPI_FLASH:
4347 Define this if you have a SPI Flash memory device which you
4348 want to use for the environment.
4350 - CONFIG_ENV_OFFSET:
4353 These two #defines specify the offset and size of the
4354 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4355 aligned to an erase sector boundary.
4357 - CONFIG_ENV_SECT_SIZE:
4359 Define the SPI flash's sector size.
4361 - CONFIG_ENV_OFFSET_REDUND (optional):
4363 This setting describes a second storage area of CONFIG_ENV_SIZE
4364 size used to hold a redundant copy of the environment data, so
4365 that there is a valid backup copy in case there is a power failure
4366 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4367 aligned to an erase sector boundary.
4369 - CONFIG_ENV_SPI_BUS (optional):
4370 - CONFIG_ENV_SPI_CS (optional):
4372 Define the SPI bus and chip select. If not defined they will be 0.
4374 - CONFIG_ENV_SPI_MAX_HZ (optional):
4376 Define the SPI max work clock. If not defined then use 1MHz.
4378 - CONFIG_ENV_SPI_MODE (optional):
4380 Define the SPI work mode. If not defined then use SPI_MODE_3.
4382 - CONFIG_ENV_IS_IN_REMOTE:
4384 Define this if you have a remote memory space which you
4385 want to use for the local device's environment.
4390 These two #defines specify the address and size of the
4391 environment area within the remote memory space. The
4392 local device can get the environment from remote memory
4393 space by SRIO or PCIE links.
4395 BE CAREFUL! For some special cases, the local device can not use
4396 "saveenv" command. For example, the local device will get the
4397 environment stored in a remote NOR flash by SRIO or PCIE link,
4398 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4400 - CONFIG_ENV_IS_IN_NAND:
4402 Define this if you have a NAND device which you want to use
4403 for the environment.
4405 - CONFIG_ENV_OFFSET:
4408 These two #defines specify the offset and size of the environment
4409 area within the first NAND device. CONFIG_ENV_OFFSET must be
4410 aligned to an erase block boundary.
4412 - CONFIG_ENV_OFFSET_REDUND (optional):
4414 This setting describes a second storage area of CONFIG_ENV_SIZE
4415 size used to hold a redundant copy of the environment data, so
4416 that there is a valid backup copy in case there is a power failure
4417 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4418 aligned to an erase block boundary.
4420 - CONFIG_ENV_RANGE (optional):
4422 Specifies the length of the region in which the environment
4423 can be written. This should be a multiple of the NAND device's
4424 block size. Specifying a range with more erase blocks than
4425 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4426 the range to be avoided.
4428 - CONFIG_ENV_OFFSET_OOB (optional):
4430 Enables support for dynamically retrieving the offset of the
4431 environment from block zero's out-of-band data. The
4432 "nand env.oob" command can be used to record this offset.
4433 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4434 using CONFIG_ENV_OFFSET_OOB.
4436 - CONFIG_NAND_ENV_DST
4438 Defines address in RAM to which the nand_spl code should copy the
4439 environment. If redundant environment is used, it will be copied to
4440 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4442 - CONFIG_ENV_IS_IN_UBI:
4444 Define this if you have an UBI volume that you want to use for the
4445 environment. This has the benefit of wear-leveling the environment
4446 accesses, which is important on NAND.
4448 - CONFIG_ENV_UBI_PART:
4450 Define this to a string that is the mtd partition containing the UBI.
4452 - CONFIG_ENV_UBI_VOLUME:
4454 Define this to the name of the volume that you want to store the
4457 - CONFIG_ENV_UBI_VOLUME_REDUND:
4459 Define this to the name of another volume to store a second copy of
4460 the environment in. This will enable redundant environments in UBI.
4461 It is assumed that both volumes are in the same MTD partition.
4463 - CONFIG_UBI_SILENCE_MSG
4464 - CONFIG_UBIFS_SILENCE_MSG
4466 You will probably want to define these to avoid a really noisy system
4467 when storing the env in UBI.
4469 - CONFIG_ENV_IS_IN_FAT:
4470 Define this if you want to use the FAT file system for the environment.
4472 - FAT_ENV_INTERFACE:
4474 Define this to a string that is the name of the block device.
4476 - FAT_ENV_DEV_AND_PART:
4478 Define this to a string to specify the partition of the device. It can
4481 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4482 - "D:P": device D partition P. Error occurs if device D has no
4485 - "D" or "D:": device D partition 1 if device D has partition
4486 table, or the whole device D if has no partition
4488 - "D:auto": first partition in device D with bootable flag set.
4489 If none, first valid partition in device D. If no
4490 partition table then means device D.
4494 It's a string of the FAT file name. This file use to store the
4498 This should be defined. Otherwise it cannot save the environment file.
4500 - CONFIG_ENV_IS_IN_MMC:
4502 Define this if you have an MMC device which you want to use for the
4505 - CONFIG_SYS_MMC_ENV_DEV:
4507 Specifies which MMC device the environment is stored in.
4509 - CONFIG_SYS_MMC_ENV_PART (optional):
4511 Specifies which MMC partition the environment is stored in. If not
4512 set, defaults to partition 0, the user area. Common values might be
4513 1 (first MMC boot partition), 2 (second MMC boot partition).
4515 - CONFIG_ENV_OFFSET:
4518 These two #defines specify the offset and size of the environment
4519 area within the specified MMC device.
4521 If offset is positive (the usual case), it is treated as relative to
4522 the start of the MMC partition. If offset is negative, it is treated
4523 as relative to the end of the MMC partition. This can be useful if
4524 your board may be fitted with different MMC devices, which have
4525 different sizes for the MMC partitions, and you always want the
4526 environment placed at the very end of the partition, to leave the
4527 maximum possible space before it, to store other data.
4529 These two values are in units of bytes, but must be aligned to an
4530 MMC sector boundary.
4532 - CONFIG_ENV_OFFSET_REDUND (optional):
4534 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4535 hold a redundant copy of the environment data. This provides a
4536 valid backup copy in case the other copy is corrupted, e.g. due
4537 to a power failure during a "saveenv" operation.
4539 This value may also be positive or negative; this is handled in the
4540 same way as CONFIG_ENV_OFFSET.
4542 This value is also in units of bytes, but must also be aligned to
4543 an MMC sector boundary.
4545 - CONFIG_ENV_SIZE_REDUND (optional):
4547 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4548 set. If this value is set, it must be set to the same value as
4551 - CONFIG_SYS_SPI_INIT_OFFSET
4553 Defines offset to the initial SPI buffer area in DPRAM. The
4554 area is used at an early stage (ROM part) if the environment
4555 is configured to reside in the SPI EEPROM: We need a 520 byte
4556 scratch DPRAM area. It is used between the two initialization
4557 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4558 to be a good choice since it makes it far enough from the
4559 start of the data area as well as from the stack pointer.
4561 Please note that the environment is read-only until the monitor
4562 has been relocated to RAM and a RAM copy of the environment has been
4563 created; also, when using EEPROM you will have to use getenv_f()
4564 until then to read environment variables.
4566 The environment is protected by a CRC32 checksum. Before the monitor
4567 is relocated into RAM, as a result of a bad CRC you will be working
4568 with the compiled-in default environment - *silently*!!! [This is
4569 necessary, because the first environment variable we need is the
4570 "baudrate" setting for the console - if we have a bad CRC, we don't
4571 have any device yet where we could complain.]
4573 Note: once the monitor has been relocated, then it will complain if
4574 the default environment is used; a new CRC is computed as soon as you
4575 use the "saveenv" command to store a valid environment.
4577 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4578 Echo the inverted Ethernet link state to the fault LED.
4580 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4581 also needs to be defined.
4583 - CONFIG_SYS_FAULT_MII_ADDR:
4584 MII address of the PHY to check for the Ethernet link state.
4586 - CONFIG_NS16550_MIN_FUNCTIONS:
4587 Define this if you desire to only have use of the NS16550_init
4588 and NS16550_putc functions for the serial driver located at
4589 drivers/serial/ns16550.c. This option is useful for saving
4590 space for already greatly restricted images, including but not
4591 limited to NAND_SPL configurations.
4593 - CONFIG_DISPLAY_BOARDINFO
4594 Display information about the board that U-Boot is running on
4595 when U-Boot starts up. The board function checkboard() is called
4598 - CONFIG_DISPLAY_BOARDINFO_LATE
4599 Similar to the previous option, but display this information
4600 later, once stdio is running and output goes to the LCD, if
4603 - CONFIG_BOARD_SIZE_LIMIT:
4604 Maximum size of the U-Boot image. When defined, the
4605 build system checks that the actual size does not
4608 Low Level (hardware related) configuration options:
4609 ---------------------------------------------------
4611 - CONFIG_SYS_CACHELINE_SIZE:
4612 Cache Line Size of the CPU.
4614 - CONFIG_SYS_DEFAULT_IMMR:
4615 Default address of the IMMR after system reset.
4617 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4618 and RPXsuper) to be able to adjust the position of
4619 the IMMR register after a reset.
4621 - CONFIG_SYS_CCSRBAR_DEFAULT:
4622 Default (power-on reset) physical address of CCSR on Freescale
4625 - CONFIG_SYS_CCSRBAR:
4626 Virtual address of CCSR. On a 32-bit build, this is typically
4627 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4629 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4630 for cross-platform code that uses that macro instead.
4632 - CONFIG_SYS_CCSRBAR_PHYS:
4633 Physical address of CCSR. CCSR can be relocated to a new
4634 physical address, if desired. In this case, this macro should
4635 be set to that address. Otherwise, it should be set to the
4636 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4637 is typically relocated on 36-bit builds. It is recommended
4638 that this macro be defined via the _HIGH and _LOW macros:
4640 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4641 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4643 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4644 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4645 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4646 used in assembly code, so it must not contain typecasts or
4647 integer size suffixes (e.g. "ULL").
4649 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4650 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4651 used in assembly code, so it must not contain typecasts or
4652 integer size suffixes (e.g. "ULL").
4654 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4655 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4656 forced to a value that ensures that CCSR is not relocated.
4658 - Floppy Disk Support:
4659 CONFIG_SYS_FDC_DRIVE_NUMBER
4661 the default drive number (default value 0)
4663 CONFIG_SYS_ISA_IO_STRIDE
4665 defines the spacing between FDC chipset registers
4668 CONFIG_SYS_ISA_IO_OFFSET
4670 defines the offset of register from address. It
4671 depends on which part of the data bus is connected to
4672 the FDC chipset. (default value 0)
4674 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4675 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4678 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4679 fdc_hw_init() is called at the beginning of the FDC
4680 setup. fdc_hw_init() must be provided by the board
4681 source code. It is used to make hardware-dependent
4685 Most IDE controllers were designed to be connected with PCI
4686 interface. Only few of them were designed for AHB interface.
4687 When software is doing ATA command and data transfer to
4688 IDE devices through IDE-AHB controller, some additional
4689 registers accessing to these kind of IDE-AHB controller
4692 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4693 DO NOT CHANGE unless you know exactly what you're
4694 doing! (11-4) [MPC8xx/82xx systems only]
4696 - CONFIG_SYS_INIT_RAM_ADDR:
4698 Start address of memory area that can be used for
4699 initial data and stack; please note that this must be
4700 writable memory that is working WITHOUT special
4701 initialization, i. e. you CANNOT use normal RAM which
4702 will become available only after programming the
4703 memory controller and running certain initialization
4706 U-Boot uses the following memory types:
4707 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4708 - MPC824X: data cache
4709 - PPC4xx: data cache
4711 - CONFIG_SYS_GBL_DATA_OFFSET:
4713 Offset of the initial data structure in the memory
4714 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4715 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4716 data is located at the end of the available space
4717 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4718 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4719 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4720 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4723 On the MPC824X (or other systems that use the data
4724 cache for initial memory) the address chosen for
4725 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4726 point to an otherwise UNUSED address space between
4727 the top of RAM and the start of the PCI space.
4729 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4731 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4733 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4735 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4737 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4739 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4741 - CONFIG_SYS_OR_TIMING_SDRAM:
4744 - CONFIG_SYS_MAMR_PTA:
4745 periodic timer for refresh
4747 - CONFIG_SYS_DER: Debug Event Register (37-47)
4749 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4750 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4751 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4752 CONFIG_SYS_BR1_PRELIM:
4753 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4755 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4756 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4757 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4758 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4760 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4761 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4762 Machine Mode Register and Memory Periodic Timer
4763 Prescaler definitions (SDRAM timing)
4765 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4766 enable I2C microcode relocation patch (MPC8xx);
4767 define relocation offset in DPRAM [DSP2]
4769 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4770 enable SMC microcode relocation patch (MPC8xx);
4771 define relocation offset in DPRAM [SMC1]
4773 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4774 enable SPI microcode relocation patch (MPC8xx);
4775 define relocation offset in DPRAM [SCC4]
4777 - CONFIG_SYS_USE_OSCCLK:
4778 Use OSCM clock mode on MBX8xx board. Be careful,
4779 wrong setting might damage your board. Read
4780 doc/README.MBX before setting this variable!
4782 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4783 Offset of the bootmode word in DPRAM used by post
4784 (Power On Self Tests). This definition overrides
4785 #define'd default value in commproc.h resp.
4788 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4789 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4790 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4791 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4792 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4793 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4794 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4795 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4796 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4798 - CONFIG_PCI_DISABLE_PCIE:
4799 Disable PCI-Express on systems where it is supported but not
4802 - CONFIG_PCI_ENUM_ONLY
4803 Only scan through and get the devices on the buses.
4804 Don't do any setup work, presumably because someone or
4805 something has already done it, and we don't need to do it
4806 a second time. Useful for platforms that are pre-booted
4807 by coreboot or similar.
4809 - CONFIG_PCI_INDIRECT_BRIDGE:
4810 Enable support for indirect PCI bridges.
4813 Chip has SRIO or not
4816 Board has SRIO 1 port available
4819 Board has SRIO 2 port available
4821 - CONFIG_SRIO_PCIE_BOOT_MASTER
4822 Board can support master function for Boot from SRIO and PCIE
4824 - CONFIG_SYS_SRIOn_MEM_VIRT:
4825 Virtual Address of SRIO port 'n' memory region
4827 - CONFIG_SYS_SRIOn_MEM_PHYS:
4828 Physical Address of SRIO port 'n' memory region
4830 - CONFIG_SYS_SRIOn_MEM_SIZE:
4831 Size of SRIO port 'n' memory region
4833 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4834 Defined to tell the NAND controller that the NAND chip is using
4836 Not all NAND drivers use this symbol.
4837 Example of drivers that use it:
4838 - drivers/mtd/nand/ndfc.c
4839 - drivers/mtd/nand/mxc_nand.c
4841 - CONFIG_SYS_NDFC_EBC0_CFG
4842 Sets the EBC0_CFG register for the NDFC. If not defined
4843 a default value will be used.
4846 Get DDR timing information from an I2C EEPROM. Common
4847 with pluggable memory modules such as SODIMMs
4850 I2C address of the SPD EEPROM
4852 - CONFIG_SYS_SPD_BUS_NUM
4853 If SPD EEPROM is on an I2C bus other than the first
4854 one, specify here. Note that the value must resolve
4855 to something your driver can deal with.
4857 - CONFIG_SYS_DDR_RAW_TIMING
4858 Get DDR timing information from other than SPD. Common with
4859 soldered DDR chips onboard without SPD. DDR raw timing
4860 parameters are extracted from datasheet and hard-coded into
4861 header files or board specific files.
4863 - CONFIG_FSL_DDR_INTERACTIVE
4864 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4866 - CONFIG_FSL_DDR_SYNC_REFRESH
4867 Enable sync of refresh for multiple controllers.
4869 - CONFIG_FSL_DDR_BIST
4870 Enable built-in memory test for Freescale DDR controllers.
4872 - CONFIG_SYS_83XX_DDR_USES_CS0
4873 Only for 83xx systems. If specified, then DDR should
4874 be configured using CS0 and CS1 instead of CS2 and CS3.
4876 - CONFIG_ETHER_ON_FEC[12]
4877 Define to enable FEC[12] on a 8xx series processor.
4879 - CONFIG_FEC[12]_PHY
4880 Define to the hardcoded PHY address which corresponds
4881 to the given FEC; i. e.
4882 #define CONFIG_FEC1_PHY 4
4883 means that the PHY with address 4 is connected to FEC1
4885 When set to -1, means to probe for first available.
4887 - CONFIG_FEC[12]_PHY_NORXERR
4888 The PHY does not have a RXERR line (RMII only).
4889 (so program the FEC to ignore it).
4892 Enable RMII mode for all FECs.
4893 Note that this is a global option, we can't
4894 have one FEC in standard MII mode and another in RMII mode.
4896 - CONFIG_CRC32_VERIFY
4897 Add a verify option to the crc32 command.
4900 => crc32 -v <address> <count> <crc32>
4902 Where address/count indicate a memory area
4903 and crc32 is the correct crc32 which the
4907 Add the "loopw" memory command. This only takes effect if
4908 the memory commands are activated globally (CONFIG_CMD_MEM).
4911 Add the "mdc" and "mwc" memory commands. These are cyclic
4916 This command will print 4 bytes (10,11,12,13) each 500 ms.
4918 => mwc.l 100 12345678 10
4919 This command will write 12345678 to address 100 all 10 ms.
4921 This only takes effect if the memory commands are activated
4922 globally (CONFIG_CMD_MEM).
4924 - CONFIG_SKIP_LOWLEVEL_INIT
4925 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4926 low level initializations (like setting up the memory
4927 controller) are omitted and/or U-Boot does not
4928 relocate itself into RAM.
4930 Normally this variable MUST NOT be defined. The only
4931 exception is when U-Boot is loaded (to RAM) by some
4932 other boot loader or by a debugger which performs
4933 these initializations itself.
4936 Modifies the behaviour of start.S when compiling a loader
4937 that is executed before the actual U-Boot. E.g. when
4938 compiling a NAND SPL.
4941 Modifies the behaviour of start.S when compiling a loader
4942 that is executed after the SPL and before the actual U-Boot.
4943 It is loaded by the SPL.
4945 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4946 Only for 85xx systems. If this variable is specified, the section
4947 .resetvec is not kept and the section .bootpg is placed in the
4948 previous 4k of the .text section.
4950 - CONFIG_ARCH_MAP_SYSMEM
4951 Generally U-Boot (and in particular the md command) uses
4952 effective address. It is therefore not necessary to regard
4953 U-Boot address as virtual addresses that need to be translated
4954 to physical addresses. However, sandbox requires this, since
4955 it maintains its own little RAM buffer which contains all
4956 addressable memory. This option causes some memory accesses
4957 to be mapped through map_sysmem() / unmap_sysmem().
4959 - CONFIG_USE_ARCH_MEMCPY
4960 CONFIG_USE_ARCH_MEMSET
4961 If these options are used a optimized version of memcpy/memset will
4962 be used if available. These functions may be faster under some
4963 conditions but may increase the binary size.
4965 - CONFIG_X86_RESET_VECTOR
4966 If defined, the x86 reset vector code is included. This is not
4967 needed when U-Boot is running from Coreboot.
4970 Defines the MPU clock speed (in MHz).
4972 NOTE : currently only supported on AM335x platforms.
4974 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4975 Enables the RTC32K OSC on AM33xx based plattforms
4977 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4978 Option to disable subpage write in NAND driver
4979 driver that uses this:
4980 drivers/mtd/nand/davinci_nand.c
4982 Freescale QE/FMAN Firmware Support:
4983 -----------------------------------
4985 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4986 loading of "firmware", which is encoded in the QE firmware binary format.
4987 This firmware often needs to be loaded during U-Boot booting, so macros
4988 are used to identify the storage device (NOR flash, SPI, etc) and the address
4991 - CONFIG_SYS_FMAN_FW_ADDR
4992 The address in the storage device where the FMAN microcode is located. The
4993 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4996 - CONFIG_SYS_QE_FW_ADDR
4997 The address in the storage device where the QE microcode is located. The
4998 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
5001 - CONFIG_SYS_QE_FMAN_FW_LENGTH
5002 The maximum possible size of the firmware. The firmware binary format
5003 has a field that specifies the actual size of the firmware, but it
5004 might not be possible to read any part of the firmware unless some
5005 local storage is allocated to hold the entire firmware first.
5007 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
5008 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
5009 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
5010 virtual address in NOR flash.
5012 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
5013 Specifies that QE/FMAN firmware is located in NAND flash.
5014 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
5016 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
5017 Specifies that QE/FMAN firmware is located on the primary SD/MMC
5018 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5020 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
5021 Specifies that QE/FMAN firmware is located on the primary SPI
5022 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
5024 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
5025 Specifies that QE/FMAN firmware is located in the remote (master)
5026 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
5027 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
5028 window->master inbound window->master LAW->the ucode address in
5029 master's memory space.
5031 Freescale Layerscape Management Complex Firmware Support:
5032 ---------------------------------------------------------
5033 The Freescale Layerscape Management Complex (MC) supports the loading of
5035 This firmware often needs to be loaded during U-Boot booting, so macros
5036 are used to identify the storage device (NOR flash, SPI, etc) and the address
5039 - CONFIG_FSL_MC_ENET
5040 Enable the MC driver for Layerscape SoCs.
5042 - CONFIG_SYS_LS_MC_FW_ADDR
5043 The address in the storage device where the firmware is located. The
5044 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
5047 - CONFIG_SYS_LS_MC_FW_LENGTH
5048 The maximum possible size of the firmware. The firmware binary format
5049 has a field that specifies the actual size of the firmware, but it
5050 might not be possible to read any part of the firmware unless some
5051 local storage is allocated to hold the entire firmware first.
5053 - CONFIG_SYS_LS_MC_FW_IN_NOR
5054 Specifies that MC firmware is located in NOR flash, mapped as
5055 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
5056 virtual address in NOR flash.
5058 Freescale Layerscape Debug Server Support:
5059 -------------------------------------------
5060 The Freescale Layerscape Debug Server Support supports the loading of
5061 "Debug Server firmware" and triggering SP boot-rom.
5062 This firmware often needs to be loaded during U-Boot booting.
5064 - CONFIG_FSL_DEBUG_SERVER
5065 Enable the Debug Server for Layerscape SoCs.
5067 - CONFIG_SYS_DEBUG_SERVER_DRAM_BLOCK_MIN_SIZE
5068 Define minimum DDR size required for debug server image
5070 - CONFIG_SYS_MEM_TOP_HIDE_MIN
5071 Define minimum DDR size to be hided from top of the DDR memory
5076 In order to achieve reproducible builds, timestamps used in the U-Boot build
5077 process have to be set to a fixed value.
5079 This is done using the SOURCE_DATE_EPOCH environment variable.
5080 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
5081 option for U-Boot or an environment variable in U-Boot.
5083 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
5085 Building the Software:
5086 ======================
5088 Building U-Boot has been tested in several native build environments
5089 and in many different cross environments. Of course we cannot support
5090 all possibly existing versions of cross development tools in all
5091 (potentially obsolete) versions. In case of tool chain problems we
5092 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
5093 which is extensively used to build and test U-Boot.
5095 If you are not using a native environment, it is assumed that you
5096 have GNU cross compiling tools available in your path. In this case,
5097 you must set the environment variable CROSS_COMPILE in your shell.
5098 Note that no changes to the Makefile or any other source files are
5099 necessary. For example using the ELDK on a 4xx CPU, please enter:
5101 $ CROSS_COMPILE=ppc_4xx-
5102 $ export CROSS_COMPILE
5104 Note: If you wish to generate Windows versions of the utilities in
5105 the tools directory you can use the MinGW toolchain
5106 (http://www.mingw.org). Set your HOST tools to the MinGW
5107 toolchain and execute 'make tools'. For example:
5109 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
5111 Binaries such as tools/mkimage.exe will be created which can
5112 be executed on computers running Windows.
5114 U-Boot is intended to be simple to build. After installing the
5115 sources you must configure U-Boot for one specific board type. This
5120 where "NAME_defconfig" is the name of one of the existing configu-
5121 rations; see boards.cfg for supported names.
5123 Note: for some board special configuration names may exist; check if
5124 additional information is available from the board vendor; for
5125 instance, the TQM823L systems are available without (standard)
5126 or with LCD support. You can select such additional "features"
5127 when choosing the configuration, i. e.
5129 make TQM823L_defconfig
5130 - will configure for a plain TQM823L, i. e. no LCD support
5132 make TQM823L_LCD_defconfig
5133 - will configure for a TQM823L with U-Boot console on LCD
5138 Finally, type "make all", and you should get some working U-Boot
5139 images ready for download to / installation on your system:
5141 - "u-boot.bin" is a raw binary image
5142 - "u-boot" is an image in ELF binary format
5143 - "u-boot.srec" is in Motorola S-Record format
5145 By default the build is performed locally and the objects are saved
5146 in the source directory. One of the two methods can be used to change
5147 this behavior and build U-Boot to some external directory:
5149 1. Add O= to the make command line invocations:
5151 make O=/tmp/build distclean
5152 make O=/tmp/build NAME_defconfig
5153 make O=/tmp/build all
5155 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
5157 export KBUILD_OUTPUT=/tmp/build
5162 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
5166 Please be aware that the Makefiles assume you are using GNU make, so
5167 for instance on NetBSD you might need to use "gmake" instead of
5171 If the system board that you have is not listed, then you will need
5172 to port U-Boot to your hardware platform. To do this, follow these
5175 1. Add a new configuration option for your board to the toplevel
5176 "boards.cfg" file, using the existing entries as examples.
5177 Follow the instructions there to keep the boards in order.
5178 2. Create a new directory to hold your board specific code. Add any
5179 files you need. In your board directory, you will need at least
5180 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
5181 3. Create a new configuration file "include/configs/<board>.h" for
5183 3. If you're porting U-Boot to a new CPU, then also create a new
5184 directory to hold your CPU specific code. Add any files you need.
5185 4. Run "make <board>_defconfig" with your new name.
5186 5. Type "make", and you should get a working "u-boot.srec" file
5187 to be installed on your target system.
5188 6. Debug and solve any problems that might arise.
5189 [Of course, this last step is much harder than it sounds.]
5192 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5193 ==============================================================
5195 If you have modified U-Boot sources (for instance added a new board
5196 or support for new devices, a new CPU, etc.) you are expected to
5197 provide feedback to the other developers. The feedback normally takes
5198 the form of a "patch", i. e. a context diff against a certain (latest
5199 official or latest in the git repository) version of U-Boot sources.
5201 But before you submit such a patch, please verify that your modifi-
5202 cation did not break existing code. At least make sure that *ALL* of
5203 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5204 just run the "MAKEALL" script, which will configure and build U-Boot
5205 for ALL supported system. Be warned, this will take a while. You can
5206 select which (cross) compiler to use by passing a `CROSS_COMPILE'
5207 environment variable to the script, i. e. to use the ELDK cross tools
5210 CROSS_COMPILE=ppc_8xx- MAKEALL
5212 or to build on a native PowerPC system you can type
5214 CROSS_COMPILE=' ' MAKEALL
5216 When using the MAKEALL script, the default behaviour is to build
5217 U-Boot in the source directory. This location can be changed by
5218 setting the BUILD_DIR environment variable. Also, for each target
5219 built, the MAKEALL script saves two log files (<target>.ERR and
5220 <target>.MAKEALL) in the <source dir>/LOG directory. This default
5221 location can be changed by setting the MAKEALL_LOGDIR environment
5222 variable. For example:
5224 export BUILD_DIR=/tmp/build
5225 export MAKEALL_LOGDIR=/tmp/log
5226 CROSS_COMPILE=ppc_8xx- MAKEALL
5228 With the above settings build objects are saved in the /tmp/build,
5229 log files are saved in the /tmp/log and the source tree remains clean
5230 during the whole build process.
5233 See also "U-Boot Porting Guide" below.
5236 Monitor Commands - Overview:
5237 ============================
5239 go - start application at address 'addr'
5240 run - run commands in an environment variable
5241 bootm - boot application image from memory
5242 bootp - boot image via network using BootP/TFTP protocol
5243 bootz - boot zImage from memory
5244 tftpboot- boot image via network using TFTP protocol
5245 and env variables "ipaddr" and "serverip"
5246 (and eventually "gatewayip")
5247 tftpput - upload a file via network using TFTP protocol
5248 rarpboot- boot image via network using RARP/TFTP protocol
5249 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5250 loads - load S-Record file over serial line
5251 loadb - load binary file over serial line (kermit mode)
5253 mm - memory modify (auto-incrementing)
5254 nm - memory modify (constant address)
5255 mw - memory write (fill)
5257 cmp - memory compare
5258 crc32 - checksum calculation
5259 i2c - I2C sub-system
5260 sspi - SPI utility commands
5261 base - print or set address offset
5262 printenv- print environment variables
5263 setenv - set environment variables
5264 saveenv - save environment variables to persistent storage
5265 protect - enable or disable FLASH write protection
5266 erase - erase FLASH memory
5267 flinfo - print FLASH memory information
5268 nand - NAND memory operations (see doc/README.nand)
5269 bdinfo - print Board Info structure
5270 iminfo - print header information for application image
5271 coninfo - print console devices and informations
5272 ide - IDE sub-system
5273 loop - infinite loop on address range
5274 loopw - infinite write loop on address range
5275 mtest - simple RAM test
5276 icache - enable or disable instruction cache
5277 dcache - enable or disable data cache
5278 reset - Perform RESET of the CPU
5279 echo - echo args to console
5280 version - print monitor version
5281 help - print online help
5282 ? - alias for 'help'
5285 Monitor Commands - Detailed Description:
5286 ========================================
5290 For now: just type "help <command>".
5293 Environment Variables:
5294 ======================
5296 U-Boot supports user configuration using Environment Variables which
5297 can be made persistent by saving to Flash memory.
5299 Environment Variables are set using "setenv", printed using
5300 "printenv", and saved to Flash using "saveenv". Using "setenv"
5301 without a value can be used to delete a variable from the
5302 environment. As long as you don't save the environment you are
5303 working with an in-memory copy. In case the Flash area containing the
5304 environment is erased by accident, a default environment is provided.
5306 Some configuration options can be set using Environment Variables.
5308 List of environment variables (most likely not complete):
5310 baudrate - see CONFIG_BAUDRATE
5312 bootdelay - see CONFIG_BOOTDELAY
5314 bootcmd - see CONFIG_BOOTCOMMAND
5316 bootargs - Boot arguments when booting an RTOS image
5318 bootfile - Name of the image to load with TFTP
5320 bootm_low - Memory range available for image processing in the bootm
5321 command can be restricted. This variable is given as
5322 a hexadecimal number and defines lowest address allowed
5323 for use by the bootm command. See also "bootm_size"
5324 environment variable. Address defined by "bootm_low" is
5325 also the base of the initial memory mapping for the Linux
5326 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5329 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5330 This variable is given as a hexadecimal number and it
5331 defines the size of the memory region starting at base
5332 address bootm_low that is accessible by the Linux kernel
5333 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5334 as the default value if it is defined, and bootm_size is
5337 bootm_size - Memory range available for image processing in the bootm
5338 command can be restricted. This variable is given as
5339 a hexadecimal number and defines the size of the region
5340 allowed for use by the bootm command. See also "bootm_low"
5341 environment variable.
5343 updatefile - Location of the software update file on a TFTP server, used
5344 by the automatic software update feature. Please refer to
5345 documentation in doc/README.update for more details.
5347 autoload - if set to "no" (any string beginning with 'n'),
5348 "bootp" will just load perform a lookup of the
5349 configuration from the BOOTP server, but not try to
5350 load any image using TFTP
5352 autostart - if set to "yes", an image loaded using the "bootp",
5353 "rarpboot", "tftpboot" or "diskboot" commands will
5354 be automatically started (by internally calling
5357 If set to "no", a standalone image passed to the
5358 "bootm" command will be copied to the load address
5359 (and eventually uncompressed), but NOT be started.
5360 This can be used to load and uncompress arbitrary
5363 fdt_high - if set this restricts the maximum address that the
5364 flattened device tree will be copied into upon boot.
5365 For example, if you have a system with 1 GB memory
5366 at physical address 0x10000000, while Linux kernel
5367 only recognizes the first 704 MB as low memory, you
5368 may need to set fdt_high as 0x3C000000 to have the
5369 device tree blob be copied to the maximum address
5370 of the 704 MB low memory, so that Linux kernel can
5371 access it during the boot procedure.
5373 If this is set to the special value 0xFFFFFFFF then
5374 the fdt will not be copied at all on boot. For this
5375 to work it must reside in writable memory, have
5376 sufficient padding on the end of it for u-boot to
5377 add the information it needs into it, and the memory
5378 must be accessible by the kernel.
5380 fdtcontroladdr- if set this is the address of the control flattened
5381 device tree used by U-Boot when CONFIG_OF_CONTROL is
5384 i2cfast - (PPC405GP|PPC405EP only)
5385 if set to 'y' configures Linux I2C driver for fast
5386 mode (400kHZ). This environment variable is used in
5387 initialization code. So, for changes to be effective
5388 it must be saved and board must be reset.
5390 initrd_high - restrict positioning of initrd images:
5391 If this variable is not set, initrd images will be
5392 copied to the highest possible address in RAM; this
5393 is usually what you want since it allows for
5394 maximum initrd size. If for some reason you want to
5395 make sure that the initrd image is loaded below the
5396 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5397 variable to a value of "no" or "off" or "0".
5398 Alternatively, you can set it to a maximum upper
5399 address to use (U-Boot will still check that it
5400 does not overwrite the U-Boot stack and data).
5402 For instance, when you have a system with 16 MB
5403 RAM, and want to reserve 4 MB from use by Linux,
5404 you can do this by adding "mem=12M" to the value of
5405 the "bootargs" variable. However, now you must make
5406 sure that the initrd image is placed in the first
5407 12 MB as well - this can be done with
5409 setenv initrd_high 00c00000
5411 If you set initrd_high to 0xFFFFFFFF, this is an
5412 indication to U-Boot that all addresses are legal
5413 for the Linux kernel, including addresses in flash
5414 memory. In this case U-Boot will NOT COPY the
5415 ramdisk at all. This may be useful to reduce the
5416 boot time on your system, but requires that this
5417 feature is supported by your Linux kernel.
5419 ipaddr - IP address; needed for tftpboot command
5421 loadaddr - Default load address for commands like "bootp",
5422 "rarpboot", "tftpboot", "loadb" or "diskboot"
5424 loads_echo - see CONFIG_LOADS_ECHO
5426 serverip - TFTP server IP address; needed for tftpboot command
5428 bootretry - see CONFIG_BOOT_RETRY_TIME
5430 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5432 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5434 ethprime - controls which interface is used first.
5436 ethact - controls which interface is currently active.
5437 For example you can do the following
5439 => setenv ethact FEC
5440 => ping 192.168.0.1 # traffic sent on FEC
5441 => setenv ethact SCC
5442 => ping 10.0.0.1 # traffic sent on SCC
5444 ethrotate - When set to "no" U-Boot does not go through all
5445 available network interfaces.
5446 It just stays at the currently selected interface.
5448 netretry - When set to "no" each network operation will
5449 either succeed or fail without retrying.
5450 When set to "once" the network operation will
5451 fail when all the available network interfaces
5452 are tried once without success.
5453 Useful on scripts which control the retry operation
5456 npe_ucode - set load address for the NPE microcode
5458 silent_linux - If set then Linux will be told to boot silently, by
5459 changing the console to be empty. If "yes" it will be
5460 made silent. If "no" it will not be made silent. If
5461 unset, then it will be made silent if the U-Boot console
5464 tftpsrcp - If this is set, the value is used for TFTP's
5467 tftpdstp - If this is set, the value is used for TFTP's UDP
5468 destination port instead of the Well Know Port 69.
5470 tftpblocksize - Block size to use for TFTP transfers; if not set,
5471 we use the TFTP server's default block size
5473 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5474 seconds, minimum value is 1000 = 1 second). Defines
5475 when a packet is considered to be lost so it has to
5476 be retransmitted. The default is 5000 = 5 seconds.
5477 Lowering this value may make downloads succeed
5478 faster in networks with high packet loss rates or
5479 with unreliable TFTP servers.
5481 tftptimeoutcountmax - maximum count of TFTP timeouts (no
5482 unit, minimum value = 0). Defines how many timeouts
5483 can happen during a single file transfer before that
5484 transfer is aborted. The default is 10, and 0 means
5485 'no timeouts allowed'. Increasing this value may help
5486 downloads succeed with high packet loss rates, or with
5487 unreliable TFTP servers or client hardware.
5489 vlan - When set to a value < 4095 the traffic over
5490 Ethernet is encapsulated/received over 802.1q
5493 The following image location variables contain the location of images
5494 used in booting. The "Image" column gives the role of the image and is
5495 not an environment variable name. The other columns are environment
5496 variable names. "File Name" gives the name of the file on a TFTP
5497 server, "RAM Address" gives the location in RAM the image will be
5498 loaded to, and "Flash Location" gives the image's address in NOR
5499 flash or offset in NAND flash.
5501 *Note* - these variables don't have to be defined for all boards, some
5502 boards currently use other variables for these purposes, and some
5503 boards use these variables for other purposes.
5505 Image File Name RAM Address Flash Location
5506 ----- --------- ----------- --------------
5507 u-boot u-boot u-boot_addr_r u-boot_addr
5508 Linux kernel bootfile kernel_addr_r kernel_addr
5509 device tree blob fdtfile fdt_addr_r fdt_addr
5510 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5512 The following environment variables may be used and automatically
5513 updated by the network boot commands ("bootp" and "rarpboot"),
5514 depending the information provided by your boot server:
5516 bootfile - see above
5517 dnsip - IP address of your Domain Name Server
5518 dnsip2 - IP address of your secondary Domain Name Server
5519 gatewayip - IP address of the Gateway (Router) to use
5520 hostname - Target hostname
5522 netmask - Subnet Mask
5523 rootpath - Pathname of the root filesystem on the NFS server
5524 serverip - see above
5527 There are two special Environment Variables:
5529 serial# - contains hardware identification information such
5530 as type string and/or serial number
5531 ethaddr - Ethernet address
5533 These variables can be set only once (usually during manufacturing of
5534 the board). U-Boot refuses to delete or overwrite these variables
5535 once they have been set once.
5538 Further special Environment Variables:
5540 ver - Contains the U-Boot version string as printed
5541 with the "version" command. This variable is
5542 readonly (see CONFIG_VERSION_VARIABLE).
5545 Please note that changes to some configuration parameters may take
5546 only effect after the next boot (yes, that's just like Windoze :-).
5549 Callback functions for environment variables:
5550 ---------------------------------------------
5552 For some environment variables, the behavior of u-boot needs to change
5553 when their values are changed. This functionality allows functions to
5554 be associated with arbitrary variables. On creation, overwrite, or
5555 deletion, the callback will provide the opportunity for some side
5556 effect to happen or for the change to be rejected.
5558 The callbacks are named and associated with a function using the
5559 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5561 These callbacks are associated with variables in one of two ways. The
5562 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5563 in the board configuration to a string that defines a list of
5564 associations. The list must be in the following format:
5566 entry = variable_name[:callback_name]
5569 If the callback name is not specified, then the callback is deleted.
5570 Spaces are also allowed anywhere in the list.
5572 Callbacks can also be associated by defining the ".callbacks" variable
5573 with the same list format above. Any association in ".callbacks" will
5574 override any association in the static list. You can define
5575 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5576 ".callbacks" environment variable in the default or embedded environment.
5578 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5579 regular expression. This allows multiple variables to be connected to
5580 the same callback without explicitly listing them all out.
5583 Command Line Parsing:
5584 =====================
5586 There are two different command line parsers available with U-Boot:
5587 the old "simple" one, and the much more powerful "hush" shell:
5589 Old, simple command line parser:
5590 --------------------------------
5592 - supports environment variables (through setenv / saveenv commands)
5593 - several commands on one line, separated by ';'
5594 - variable substitution using "... ${name} ..." syntax
5595 - special characters ('$', ';') can be escaped by prefixing with '\',
5597 setenv bootcmd bootm \${address}
5598 - You can also escape text by enclosing in single apostrophes, for example:
5599 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5604 - similar to Bourne shell, with control structures like
5605 if...then...else...fi, for...do...done; while...do...done,
5606 until...do...done, ...
5607 - supports environment ("global") variables (through setenv / saveenv
5608 commands) and local shell variables (through standard shell syntax
5609 "name=value"); only environment variables can be used with "run"
5615 (1) If a command line (or an environment variable executed by a "run"
5616 command) contains several commands separated by semicolon, and
5617 one of these commands fails, then the remaining commands will be
5620 (2) If you execute several variables with one call to run (i. e.
5621 calling run with a list of variables as arguments), any failing
5622 command will cause "run" to terminate, i. e. the remaining
5623 variables are not executed.
5625 Note for Redundant Ethernet Interfaces:
5626 =======================================
5628 Some boards come with redundant Ethernet interfaces; U-Boot supports
5629 such configurations and is capable of automatic selection of a
5630 "working" interface when needed. MAC assignment works as follows:
5632 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5633 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5634 "eth1addr" (=>eth1), "eth2addr", ...
5636 If the network interface stores some valid MAC address (for instance
5637 in SROM), this is used as default address if there is NO correspon-
5638 ding setting in the environment; if the corresponding environment
5639 variable is set, this overrides the settings in the card; that means:
5641 o If the SROM has a valid MAC address, and there is no address in the
5642 environment, the SROM's address is used.
5644 o If there is no valid address in the SROM, and a definition in the
5645 environment exists, then the value from the environment variable is
5648 o If both the SROM and the environment contain a MAC address, and
5649 both addresses are the same, this MAC address is used.
5651 o If both the SROM and the environment contain a MAC address, and the
5652 addresses differ, the value from the environment is used and a
5655 o If neither SROM nor the environment contain a MAC address, an error
5656 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5657 a random, locally-assigned MAC is used.
5659 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5660 will be programmed into hardware as part of the initialization process. This
5661 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5662 The naming convention is as follows:
5663 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5668 U-Boot is capable of booting (and performing other auxiliary operations on)
5669 images in two formats:
5671 New uImage format (FIT)
5672 -----------------------
5674 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5675 to Flattened Device Tree). It allows the use of images with multiple
5676 components (several kernels, ramdisks, etc.), with contents protected by
5677 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5683 Old image format is based on binary files which can be basically anything,
5684 preceded by a special header; see the definitions in include/image.h for
5685 details; basically, the header defines the following image properties:
5687 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5688 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5689 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5690 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5692 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5693 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5694 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5695 * Compression Type (uncompressed, gzip, bzip2)
5701 The header is marked by a special Magic Number, and both the header
5702 and the data portions of the image are secured against corruption by
5709 Although U-Boot should support any OS or standalone application
5710 easily, the main focus has always been on Linux during the design of
5713 U-Boot includes many features that so far have been part of some
5714 special "boot loader" code within the Linux kernel. Also, any
5715 "initrd" images to be used are no longer part of one big Linux image;
5716 instead, kernel and "initrd" are separate images. This implementation
5717 serves several purposes:
5719 - the same features can be used for other OS or standalone
5720 applications (for instance: using compressed images to reduce the
5721 Flash memory footprint)
5723 - it becomes much easier to port new Linux kernel versions because
5724 lots of low-level, hardware dependent stuff are done by U-Boot
5726 - the same Linux kernel image can now be used with different "initrd"
5727 images; of course this also means that different kernel images can
5728 be run with the same "initrd". This makes testing easier (you don't
5729 have to build a new "zImage.initrd" Linux image when you just
5730 change a file in your "initrd"). Also, a field-upgrade of the
5731 software is easier now.
5737 Porting Linux to U-Boot based systems:
5738 ---------------------------------------
5740 U-Boot cannot save you from doing all the necessary modifications to
5741 configure the Linux device drivers for use with your target hardware
5742 (no, we don't intend to provide a full virtual machine interface to
5745 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5747 Just make sure your machine specific header file (for instance
5748 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5749 Information structure as we define in include/asm-<arch>/u-boot.h,
5750 and make sure that your definition of IMAP_ADDR uses the same value
5751 as your U-Boot configuration in CONFIG_SYS_IMMR.
5753 Note that U-Boot now has a driver model, a unified model for drivers.
5754 If you are adding a new driver, plumb it into driver model. If there
5755 is no uclass available, you are encouraged to create one. See
5759 Configuring the Linux kernel:
5760 -----------------------------
5762 No specific requirements for U-Boot. Make sure you have some root
5763 device (initial ramdisk, NFS) for your target system.
5766 Building a Linux Image:
5767 -----------------------
5769 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5770 not used. If you use recent kernel source, a new build target
5771 "uImage" will exist which automatically builds an image usable by
5772 U-Boot. Most older kernels also have support for a "pImage" target,
5773 which was introduced for our predecessor project PPCBoot and uses a
5774 100% compatible format.
5778 make TQM850L_defconfig
5783 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5784 encapsulate a compressed Linux kernel image with header information,
5785 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5787 * build a standard "vmlinux" kernel image (in ELF binary format):
5789 * convert the kernel into a raw binary image:
5791 ${CROSS_COMPILE}-objcopy -O binary \
5792 -R .note -R .comment \
5793 -S vmlinux linux.bin
5795 * compress the binary image:
5799 * package compressed binary image for U-Boot:
5801 mkimage -A ppc -O linux -T kernel -C gzip \
5802 -a 0 -e 0 -n "Linux Kernel Image" \
5803 -d linux.bin.gz uImage
5806 The "mkimage" tool can also be used to create ramdisk images for use
5807 with U-Boot, either separated from the Linux kernel image, or
5808 combined into one file. "mkimage" encapsulates the images with a 64
5809 byte header containing information about target architecture,
5810 operating system, image type, compression method, entry points, time
5811 stamp, CRC32 checksums, etc.
5813 "mkimage" can be called in two ways: to verify existing images and
5814 print the header information, or to build new images.
5816 In the first form (with "-l" option) mkimage lists the information
5817 contained in the header of an existing U-Boot image; this includes
5818 checksum verification:
5820 tools/mkimage -l image
5821 -l ==> list image header information
5823 The second form (with "-d" option) is used to build a U-Boot image
5824 from a "data file" which is used as image payload:
5826 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5827 -n name -d data_file image
5828 -A ==> set architecture to 'arch'
5829 -O ==> set operating system to 'os'
5830 -T ==> set image type to 'type'
5831 -C ==> set compression type 'comp'
5832 -a ==> set load address to 'addr' (hex)
5833 -e ==> set entry point to 'ep' (hex)
5834 -n ==> set image name to 'name'
5835 -d ==> use image data from 'datafile'
5837 Right now, all Linux kernels for PowerPC systems use the same load
5838 address (0x00000000), but the entry point address depends on the
5841 - 2.2.x kernels have the entry point at 0x0000000C,
5842 - 2.3.x and later kernels have the entry point at 0x00000000.
5844 So a typical call to build a U-Boot image would read:
5846 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5847 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5848 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5849 > examples/uImage.TQM850L
5850 Image Name: 2.4.4 kernel for TQM850L
5851 Created: Wed Jul 19 02:34:59 2000
5852 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5853 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5854 Load Address: 0x00000000
5855 Entry Point: 0x00000000
5857 To verify the contents of the image (or check for corruption):
5859 -> tools/mkimage -l examples/uImage.TQM850L
5860 Image Name: 2.4.4 kernel for TQM850L
5861 Created: Wed Jul 19 02:34:59 2000
5862 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5863 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5864 Load Address: 0x00000000
5865 Entry Point: 0x00000000
5867 NOTE: for embedded systems where boot time is critical you can trade
5868 speed for memory and install an UNCOMPRESSED image instead: this
5869 needs more space in Flash, but boots much faster since it does not
5870 need to be uncompressed:
5872 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5873 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5874 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5875 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5876 > examples/uImage.TQM850L-uncompressed
5877 Image Name: 2.4.4 kernel for TQM850L
5878 Created: Wed Jul 19 02:34:59 2000
5879 Image Type: PowerPC Linux Kernel Image (uncompressed)
5880 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5881 Load Address: 0x00000000
5882 Entry Point: 0x00000000
5885 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5886 when your kernel is intended to use an initial ramdisk:
5888 -> tools/mkimage -n 'Simple Ramdisk Image' \
5889 > -A ppc -O linux -T ramdisk -C gzip \
5890 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5891 Image Name: Simple Ramdisk Image
5892 Created: Wed Jan 12 14:01:50 2000
5893 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5894 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5895 Load Address: 0x00000000
5896 Entry Point: 0x00000000
5898 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5899 option performs the converse operation of the mkimage's second form (the "-d"
5900 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5903 tools/dumpimage -i image -T type -p position data_file
5904 -i ==> extract from the 'image' a specific 'data_file'
5905 -T ==> set image type to 'type'
5906 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5909 Installing a Linux Image:
5910 -------------------------
5912 To downloading a U-Boot image over the serial (console) interface,
5913 you must convert the image to S-Record format:
5915 objcopy -I binary -O srec examples/image examples/image.srec
5917 The 'objcopy' does not understand the information in the U-Boot
5918 image header, so the resulting S-Record file will be relative to
5919 address 0x00000000. To load it to a given address, you need to
5920 specify the target address as 'offset' parameter with the 'loads'
5923 Example: install the image to address 0x40100000 (which on the
5924 TQM8xxL is in the first Flash bank):
5926 => erase 40100000 401FFFFF
5932 ## Ready for S-Record download ...
5933 ~>examples/image.srec
5934 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5936 15989 15990 15991 15992
5937 [file transfer complete]
5939 ## Start Addr = 0x00000000
5942 You can check the success of the download using the 'iminfo' command;
5943 this includes a checksum verification so you can be sure no data
5944 corruption happened:
5948 ## Checking Image at 40100000 ...
5949 Image Name: 2.2.13 for initrd on TQM850L
5950 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5951 Data Size: 335725 Bytes = 327 kB = 0 MB
5952 Load Address: 00000000
5953 Entry Point: 0000000c
5954 Verifying Checksum ... OK
5960 The "bootm" command is used to boot an application that is stored in
5961 memory (RAM or Flash). In case of a Linux kernel image, the contents
5962 of the "bootargs" environment variable is passed to the kernel as
5963 parameters. You can check and modify this variable using the
5964 "printenv" and "setenv" commands:
5967 => printenv bootargs
5968 bootargs=root=/dev/ram
5970 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5972 => printenv bootargs
5973 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5976 ## Booting Linux kernel at 40020000 ...
5977 Image Name: 2.2.13 for NFS on TQM850L
5978 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5979 Data Size: 381681 Bytes = 372 kB = 0 MB
5980 Load Address: 00000000
5981 Entry Point: 0000000c
5982 Verifying Checksum ... OK
5983 Uncompressing Kernel Image ... OK
5984 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
5985 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5986 time_init: decrementer frequency = 187500000/60
5987 Calibrating delay loop... 49.77 BogoMIPS
5988 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5991 If you want to boot a Linux kernel with initial RAM disk, you pass
5992 the memory addresses of both the kernel and the initrd image (PPBCOOT
5993 format!) to the "bootm" command:
5995 => imi 40100000 40200000
5997 ## Checking Image at 40100000 ...
5998 Image Name: 2.2.13 for initrd on TQM850L
5999 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6000 Data Size: 335725 Bytes = 327 kB = 0 MB
6001 Load Address: 00000000
6002 Entry Point: 0000000c
6003 Verifying Checksum ... OK
6005 ## Checking Image at 40200000 ...
6006 Image Name: Simple Ramdisk Image
6007 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6008 Data Size: 566530 Bytes = 553 kB = 0 MB
6009 Load Address: 00000000
6010 Entry Point: 00000000
6011 Verifying Checksum ... OK
6013 => bootm 40100000 40200000
6014 ## Booting Linux kernel at 40100000 ...
6015 Image Name: 2.2.13 for initrd on TQM850L
6016 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6017 Data Size: 335725 Bytes = 327 kB = 0 MB
6018 Load Address: 00000000
6019 Entry Point: 0000000c
6020 Verifying Checksum ... OK
6021 Uncompressing Kernel Image ... OK
6022 ## Loading RAMDisk Image at 40200000 ...
6023 Image Name: Simple Ramdisk Image
6024 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
6025 Data Size: 566530 Bytes = 553 kB = 0 MB
6026 Load Address: 00000000
6027 Entry Point: 00000000
6028 Verifying Checksum ... OK
6029 Loading Ramdisk ... OK
6030 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
6031 Boot arguments: root=/dev/ram
6032 time_init: decrementer frequency = 187500000/60
6033 Calibrating delay loop... 49.77 BogoMIPS
6035 RAMDISK: Compressed image found at block 0
6036 VFS: Mounted root (ext2 filesystem).
6040 Boot Linux and pass a flat device tree:
6043 First, U-Boot must be compiled with the appropriate defines. See the section
6044 titled "Linux Kernel Interface" above for a more in depth explanation. The
6045 following is an example of how to start a kernel and pass an updated
6051 oft=oftrees/mpc8540ads.dtb
6052 => tftp $oftaddr $oft
6053 Speed: 1000, full duplex
6055 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
6056 Filename 'oftrees/mpc8540ads.dtb'.
6057 Load address: 0x300000
6060 Bytes transferred = 4106 (100a hex)
6061 => tftp $loadaddr $bootfile
6062 Speed: 1000, full duplex
6064 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
6066 Load address: 0x200000
6067 Loading:############
6069 Bytes transferred = 1029407 (fb51f hex)
6074 => bootm $loadaddr - $oftaddr
6075 ## Booting image at 00200000 ...
6076 Image Name: Linux-2.6.17-dirty
6077 Image Type: PowerPC Linux Kernel Image (gzip compressed)
6078 Data Size: 1029343 Bytes = 1005.2 kB
6079 Load Address: 00000000
6080 Entry Point: 00000000
6081 Verifying Checksum ... OK
6082 Uncompressing Kernel Image ... OK
6083 Booting using flat device tree at 0x300000
6084 Using MPC85xx ADS machine description
6085 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
6089 More About U-Boot Image Types:
6090 ------------------------------
6092 U-Boot supports the following image types:
6094 "Standalone Programs" are directly runnable in the environment
6095 provided by U-Boot; it is expected that (if they behave
6096 well) you can continue to work in U-Boot after return from
6097 the Standalone Program.
6098 "OS Kernel Images" are usually images of some Embedded OS which
6099 will take over control completely. Usually these programs
6100 will install their own set of exception handlers, device
6101 drivers, set up the MMU, etc. - this means, that you cannot
6102 expect to re-enter U-Boot except by resetting the CPU.
6103 "RAMDisk Images" are more or less just data blocks, and their
6104 parameters (address, size) are passed to an OS kernel that is
6106 "Multi-File Images" contain several images, typically an OS
6107 (Linux) kernel image and one or more data images like
6108 RAMDisks. This construct is useful for instance when you want
6109 to boot over the network using BOOTP etc., where the boot
6110 server provides just a single image file, but you want to get
6111 for instance an OS kernel and a RAMDisk image.
6113 "Multi-File Images" start with a list of image sizes, each
6114 image size (in bytes) specified by an "uint32_t" in network
6115 byte order. This list is terminated by an "(uint32_t)0".
6116 Immediately after the terminating 0 follow the images, one by
6117 one, all aligned on "uint32_t" boundaries (size rounded up to
6118 a multiple of 4 bytes).
6120 "Firmware Images" are binary images containing firmware (like
6121 U-Boot or FPGA images) which usually will be programmed to
6124 "Script files" are command sequences that will be executed by
6125 U-Boot's command interpreter; this feature is especially
6126 useful when you configure U-Boot to use a real shell (hush)
6127 as command interpreter.
6129 Booting the Linux zImage:
6130 -------------------------
6132 On some platforms, it's possible to boot Linux zImage. This is done
6133 using the "bootz" command. The syntax of "bootz" command is the same
6134 as the syntax of "bootm" command.
6136 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
6137 kernel with raw initrd images. The syntax is slightly different, the
6138 address of the initrd must be augmented by it's size, in the following
6139 format: "<initrd addres>:<initrd size>".
6145 One of the features of U-Boot is that you can dynamically load and
6146 run "standalone" applications, which can use some resources of
6147 U-Boot like console I/O functions or interrupt services.
6149 Two simple examples are included with the sources:
6154 'examples/hello_world.c' contains a small "Hello World" Demo
6155 application; it is automatically compiled when you build U-Boot.
6156 It's configured to run at address 0x00040004, so you can play with it
6160 ## Ready for S-Record download ...
6161 ~>examples/hello_world.srec
6162 1 2 3 4 5 6 7 8 9 10 11 ...
6163 [file transfer complete]
6165 ## Start Addr = 0x00040004
6167 => go 40004 Hello World! This is a test.
6168 ## Starting application at 0x00040004 ...
6179 Hit any key to exit ...
6181 ## Application terminated, rc = 0x0
6183 Another example, which demonstrates how to register a CPM interrupt
6184 handler with the U-Boot code, can be found in 'examples/timer.c'.
6185 Here, a CPM timer is set up to generate an interrupt every second.
6186 The interrupt service routine is trivial, just printing a '.'
6187 character, but this is just a demo program. The application can be
6188 controlled by the following keys:
6190 ? - print current values og the CPM Timer registers
6191 b - enable interrupts and start timer
6192 e - stop timer and disable interrupts
6193 q - quit application
6196 ## Ready for S-Record download ...
6197 ~>examples/timer.srec
6198 1 2 3 4 5 6 7 8 9 10 11 ...
6199 [file transfer complete]
6201 ## Start Addr = 0x00040004
6204 ## Starting application at 0x00040004 ...
6207 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6210 [q, b, e, ?] Set interval 1000000 us
6213 [q, b, e, ?] ........
6214 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6217 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6220 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6223 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6225 [q, b, e, ?] ...Stopping timer
6227 [q, b, e, ?] ## Application terminated, rc = 0x0
6233 Over time, many people have reported problems when trying to use the
6234 "minicom" terminal emulation program for serial download. I (wd)
6235 consider minicom to be broken, and recommend not to use it. Under
6236 Unix, I recommend to use C-Kermit for general purpose use (and
6237 especially for kermit binary protocol download ("loadb" command), and
6238 use "cu" for S-Record download ("loads" command). See
6239 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6240 for help with kermit.
6243 Nevertheless, if you absolutely want to use it try adding this
6244 configuration to your "File transfer protocols" section:
6246 Name Program Name U/D FullScr IO-Red. Multi
6247 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6248 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6254 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6255 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6257 Building requires a cross environment; it is known to work on
6258 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6259 need gmake since the Makefiles are not compatible with BSD make).
6260 Note that the cross-powerpc package does not install include files;
6261 attempting to build U-Boot will fail because <machine/ansi.h> is
6262 missing. This file has to be installed and patched manually:
6264 # cd /usr/pkg/cross/powerpc-netbsd/include
6266 # ln -s powerpc machine
6267 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6268 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6270 Native builds *don't* work due to incompatibilities between native
6271 and U-Boot include files.
6273 Booting assumes that (the first part of) the image booted is a
6274 stage-2 loader which in turn loads and then invokes the kernel
6275 proper. Loader sources will eventually appear in the NetBSD source
6276 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6277 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6280 Implementation Internals:
6281 =========================
6283 The following is not intended to be a complete description of every
6284 implementation detail. However, it should help to understand the
6285 inner workings of U-Boot and make it easier to port it to custom
6289 Initial Stack, Global Data:
6290 ---------------------------
6292 The implementation of U-Boot is complicated by the fact that U-Boot
6293 starts running out of ROM (flash memory), usually without access to
6294 system RAM (because the memory controller is not initialized yet).
6295 This means that we don't have writable Data or BSS segments, and BSS
6296 is not initialized as zero. To be able to get a C environment working
6297 at all, we have to allocate at least a minimal stack. Implementation
6298 options for this are defined and restricted by the CPU used: Some CPU
6299 models provide on-chip memory (like the IMMR area on MPC8xx and
6300 MPC826x processors), on others (parts of) the data cache can be
6301 locked as (mis-) used as memory, etc.
6303 Chris Hallinan posted a good summary of these issues to the
6304 U-Boot mailing list:
6306 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6307 From: "Chris Hallinan" <clh@net1plus.com>
6308 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6311 Correct me if I'm wrong, folks, but the way I understand it
6312 is this: Using DCACHE as initial RAM for Stack, etc, does not
6313 require any physical RAM backing up the cache. The cleverness
6314 is that the cache is being used as a temporary supply of
6315 necessary storage before the SDRAM controller is setup. It's
6316 beyond the scope of this list to explain the details, but you
6317 can see how this works by studying the cache architecture and
6318 operation in the architecture and processor-specific manuals.
6320 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6321 is another option for the system designer to use as an
6322 initial stack/RAM area prior to SDRAM being available. Either
6323 option should work for you. Using CS 4 should be fine if your
6324 board designers haven't used it for something that would
6325 cause you grief during the initial boot! It is frequently not
6328 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6329 with your processor/board/system design. The default value
6330 you will find in any recent u-boot distribution in
6331 walnut.h should work for you. I'd set it to a value larger
6332 than your SDRAM module. If you have a 64MB SDRAM module, set
6333 it above 400_0000. Just make sure your board has no resources
6334 that are supposed to respond to that address! That code in
6335 start.S has been around a while and should work as is when
6336 you get the config right.
6341 It is essential to remember this, since it has some impact on the C
6342 code for the initialization procedures:
6344 * Initialized global data (data segment) is read-only. Do not attempt
6347 * Do not use any uninitialized global data (or implicitly initialized
6348 as zero data - BSS segment) at all - this is undefined, initiali-
6349 zation is performed later (when relocating to RAM).
6351 * Stack space is very limited. Avoid big data buffers or things like
6354 Having only the stack as writable memory limits means we cannot use
6355 normal global data to share information between the code. But it
6356 turned out that the implementation of U-Boot can be greatly
6357 simplified by making a global data structure (gd_t) available to all
6358 functions. We could pass a pointer to this data as argument to _all_
6359 functions, but this would bloat the code. Instead we use a feature of
6360 the GCC compiler (Global Register Variables) to share the data: we
6361 place a pointer (gd) to the global data into a register which we
6362 reserve for this purpose.
6364 When choosing a register for such a purpose we are restricted by the
6365 relevant (E)ABI specifications for the current architecture, and by
6366 GCC's implementation.
6368 For PowerPC, the following registers have specific use:
6370 R2: reserved for system use
6371 R3-R4: parameter passing and return values
6372 R5-R10: parameter passing
6373 R13: small data area pointer
6377 (U-Boot also uses R12 as internal GOT pointer. r12
6378 is a volatile register so r12 needs to be reset when
6379 going back and forth between asm and C)
6381 ==> U-Boot will use R2 to hold a pointer to the global data
6383 Note: on PPC, we could use a static initializer (since the
6384 address of the global data structure is known at compile time),
6385 but it turned out that reserving a register results in somewhat
6386 smaller code - although the code savings are not that big (on
6387 average for all boards 752 bytes for the whole U-Boot image,
6388 624 text + 127 data).
6390 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6391 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6393 ==> U-Boot will use P3 to hold a pointer to the global data
6395 On ARM, the following registers are used:
6397 R0: function argument word/integer result
6398 R1-R3: function argument word
6399 R9: platform specific
6400 R10: stack limit (used only if stack checking is enabled)
6401 R11: argument (frame) pointer
6402 R12: temporary workspace
6405 R15: program counter
6407 ==> U-Boot will use R9 to hold a pointer to the global data
6409 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6411 On Nios II, the ABI is documented here:
6412 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6414 ==> U-Boot will use gp to hold a pointer to the global data
6416 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6417 to access small data sections, so gp is free.
6419 On NDS32, the following registers are used:
6421 R0-R1: argument/return
6423 R15: temporary register for assembler
6424 R16: trampoline register
6425 R28: frame pointer (FP)
6426 R29: global pointer (GP)
6427 R30: link register (LP)
6428 R31: stack pointer (SP)
6429 PC: program counter (PC)
6431 ==> U-Boot will use R10 to hold a pointer to the global data
6433 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6434 or current versions of GCC may "optimize" the code too much.
6439 U-Boot runs in system state and uses physical addresses, i.e. the
6440 MMU is not used either for address mapping nor for memory protection.
6442 The available memory is mapped to fixed addresses using the memory
6443 controller. In this process, a contiguous block is formed for each
6444 memory type (Flash, SDRAM, SRAM), even when it consists of several
6445 physical memory banks.
6447 U-Boot is installed in the first 128 kB of the first Flash bank (on
6448 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6449 booting and sizing and initializing DRAM, the code relocates itself
6450 to the upper end of DRAM. Immediately below the U-Boot code some
6451 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6452 configuration setting]. Below that, a structure with global Board
6453 Info data is placed, followed by the stack (growing downward).
6455 Additionally, some exception handler code is copied to the low 8 kB
6456 of DRAM (0x00000000 ... 0x00001FFF).
6458 So a typical memory configuration with 16 MB of DRAM could look like
6461 0x0000 0000 Exception Vector code
6464 0x0000 2000 Free for Application Use
6470 0x00FB FF20 Monitor Stack (Growing downward)
6471 0x00FB FFAC Board Info Data and permanent copy of global data
6472 0x00FC 0000 Malloc Arena
6475 0x00FE 0000 RAM Copy of Monitor Code
6476 ... eventually: LCD or video framebuffer
6477 ... eventually: pRAM (Protected RAM - unchanged by reset)
6478 0x00FF FFFF [End of RAM]
6481 System Initialization:
6482 ----------------------
6484 In the reset configuration, U-Boot starts at the reset entry point
6485 (on most PowerPC systems at address 0x00000100). Because of the reset
6486 configuration for CS0# this is a mirror of the on board Flash memory.
6487 To be able to re-map memory U-Boot then jumps to its link address.
6488 To be able to implement the initialization code in C, a (small!)
6489 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6490 which provide such a feature like MPC8xx or MPC8260), or in a locked
6491 part of the data cache. After that, U-Boot initializes the CPU core,
6492 the caches and the SIU.
6494 Next, all (potentially) available memory banks are mapped using a
6495 preliminary mapping. For example, we put them on 512 MB boundaries
6496 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6497 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6498 programmed for SDRAM access. Using the temporary configuration, a
6499 simple memory test is run that determines the size of the SDRAM
6502 When there is more than one SDRAM bank, and the banks are of
6503 different size, the largest is mapped first. For equal size, the first
6504 bank (CS2#) is mapped first. The first mapping is always for address
6505 0x00000000, with any additional banks following immediately to create
6506 contiguous memory starting from 0.
6508 Then, the monitor installs itself at the upper end of the SDRAM area
6509 and allocates memory for use by malloc() and for the global Board
6510 Info data; also, the exception vector code is copied to the low RAM
6511 pages, and the final stack is set up.
6513 Only after this relocation will you have a "normal" C environment;
6514 until that you are restricted in several ways, mostly because you are
6515 running from ROM, and because the code will have to be relocated to a
6519 U-Boot Porting Guide:
6520 ----------------------
6522 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6526 int main(int argc, char *argv[])
6528 sighandler_t no_more_time;
6530 signal(SIGALRM, no_more_time);
6531 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6533 if (available_money > available_manpower) {
6534 Pay consultant to port U-Boot;
6538 Download latest U-Boot source;
6540 Subscribe to u-boot mailing list;
6543 email("Hi, I am new to U-Boot, how do I get started?");
6546 Read the README file in the top level directory;
6547 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6548 Read applicable doc/*.README;
6549 Read the source, Luke;
6550 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6553 if (available_money > toLocalCurrency ($2500))
6556 Add a lot of aggravation and time;
6558 if (a similar board exists) { /* hopefully... */
6559 cp -a board/<similar> board/<myboard>
6560 cp include/configs/<similar>.h include/configs/<myboard>.h
6562 Create your own board support subdirectory;
6563 Create your own board include/configs/<myboard>.h file;
6565 Edit new board/<myboard> files
6566 Edit new include/configs/<myboard>.h
6571 Add / modify source code;
6575 email("Hi, I am having problems...");
6577 Send patch file to the U-Boot email list;
6578 if (reasonable critiques)
6579 Incorporate improvements from email list code review;
6581 Defend code as written;
6587 void no_more_time (int sig)
6596 All contributions to U-Boot should conform to the Linux kernel
6597 coding style; see the file "Documentation/CodingStyle" and the script
6598 "scripts/Lindent" in your Linux kernel source directory.
6600 Source files originating from a different project (for example the
6601 MTD subsystem) are generally exempt from these guidelines and are not
6602 reformatted to ease subsequent migration to newer versions of those
6605 Please note that U-Boot is implemented in C (and to some small parts in
6606 Assembler); no C++ is used, so please do not use C++ style comments (//)
6609 Please also stick to the following formatting rules:
6610 - remove any trailing white space
6611 - use TAB characters for indentation and vertical alignment, not spaces
6612 - make sure NOT to use DOS '\r\n' line feeds
6613 - do not add more than 2 consecutive empty lines to source files
6614 - do not add trailing empty lines to source files
6616 Submissions which do not conform to the standards may be returned
6617 with a request to reformat the changes.
6623 Since the number of patches for U-Boot is growing, we need to
6624 establish some rules. Submissions which do not conform to these rules
6625 may be rejected, even when they contain important and valuable stuff.
6627 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6629 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6630 see http://lists.denx.de/mailman/listinfo/u-boot
6632 When you send a patch, please include the following information with
6635 * For bug fixes: a description of the bug and how your patch fixes
6636 this bug. Please try to include a way of demonstrating that the
6637 patch actually fixes something.
6639 * For new features: a description of the feature and your
6642 * A CHANGELOG entry as plaintext (separate from the patch)
6644 * For major contributions, your entry to the CREDITS file
6646 * When you add support for a new board, don't forget to add a
6647 maintainer e-mail address to the boards.cfg file, too.
6649 * If your patch adds new configuration options, don't forget to
6650 document these in the README file.
6652 * The patch itself. If you are using git (which is *strongly*
6653 recommended) you can easily generate the patch using the
6654 "git format-patch". If you then use "git send-email" to send it to
6655 the U-Boot mailing list, you will avoid most of the common problems
6656 with some other mail clients.
6658 If you cannot use git, use "diff -purN OLD NEW". If your version of
6659 diff does not support these options, then get the latest version of
6662 The current directory when running this command shall be the parent
6663 directory of the U-Boot source tree (i. e. please make sure that
6664 your patch includes sufficient directory information for the
6667 We prefer patches as plain text. MIME attachments are discouraged,
6668 and compressed attachments must not be used.
6670 * If one logical set of modifications affects or creates several
6671 files, all these changes shall be submitted in a SINGLE patch file.
6673 * Changesets that contain different, unrelated modifications shall be
6674 submitted as SEPARATE patches, one patch per changeset.
6679 * Before sending the patch, run the MAKEALL script on your patched
6680 source tree and make sure that no errors or warnings are reported
6681 for any of the boards.
6683 * Keep your modifications to the necessary minimum: A patch
6684 containing several unrelated changes or arbitrary reformats will be
6685 returned with a request to re-formatting / split it.
6687 * If you modify existing code, make sure that your new code does not
6688 add to the memory footprint of the code ;-) Small is beautiful!
6689 When adding new features, these should compile conditionally only
6690 (using #ifdef), and the resulting code with the new feature
6691 disabled must not need more memory than the old code without your
6694 * Remember that there is a size limit of 100 kB per message on the
6695 u-boot mailing list. Bigger patches will be moderated. If they are
6696 reasonable and not too big, they will be acknowledged. But patches
6697 bigger than the size limit should be avoided.