2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc824x Files specific to Freescale MPC824x CPUs
205 /mpc8260 Files specific to Freescale MPC8260 CPUs
206 /mpc85xx Files specific to Freescale MPC85xx CPUs
207 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
208 /lib Architecture specific library files
209 /sh Files generic to SH architecture
210 /cpu CPU specific files
211 /sh2 Files specific to sh2 CPUs
212 /sh3 Files specific to sh3 CPUs
213 /sh4 Files specific to sh4 CPUs
214 /lib Architecture specific library files
215 /sparc Files generic to SPARC architecture
216 /cpu CPU specific files
217 /leon2 Files specific to Gaisler LEON2 SPARC CPU
218 /leon3 Files specific to Gaisler LEON3 SPARC CPU
219 /lib Architecture specific library files
220 /api Machine/arch independent API for external apps
221 /board Board dependent files
222 /common Misc architecture independent functions
223 /disk Code for disk drive partition handling
224 /doc Documentation (don't expect too much)
225 /drivers Commonly used device drivers
226 /examples Example code for standalone applications, etc.
227 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
228 /include Header Files
229 /lib Files generic to all architectures
230 /libfdt Library files to support flattened device trees
231 /lzma Library files to support LZMA decompression
232 /lzo Library files to support LZO decompression
234 /post Power On Self Test
235 /rtc Real Time Clock drivers
236 /tools Tools to build S-Record or U-Boot images, etc.
238 Software Configuration:
239 =======================
241 Configuration is usually done using C preprocessor defines; the
242 rationale behind that is to avoid dead code whenever possible.
244 There are two classes of configuration variables:
246 * Configuration _OPTIONS_:
247 These are selectable by the user and have names beginning with
250 * Configuration _SETTINGS_:
251 These depend on the hardware etc. and should not be meddled with if
252 you don't know what you're doing; they have names beginning with
255 Later we will add a configuration tool - probably similar to or even
256 identical to what's used for the Linux kernel. Right now, we have to
257 do the configuration by hand, which means creating some symbolic
258 links and editing some configuration files. We use the TQM8xxL boards
262 Selection of Processor Architecture and Board Type:
263 ---------------------------------------------------
265 For all supported boards there are ready-to-use default
266 configurations available; just type "make <board_name>_config".
268 Example: For a TQM823L module type:
273 For the Cogent platform, you need to specify the CPU type as well;
274 e.g. "make cogent_mpc8xx_config". And also configure the cogent
275 directory according to the instructions in cogent/README.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Board flavour: (if CONFIG_MPC8260ADS is defined)
327 CONFIG_SYS_8260ADS - original MPC8260ADS
328 CONFIG_SYS_8266ADS - MPC8266ADS
329 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
330 CONFIG_SYS_8272ADS - MPC8272ADS
332 - Marvell Family Member
333 CONFIG_SYS_MVFS - define it if you want to enable
334 multiple fs option at one time
335 for marvell soc family
337 - MPC824X Family Member (if CONFIG_MPC824X is defined)
338 Define exactly one of
339 CONFIG_MPC8240, CONFIG_MPC8245
341 - 8xx CPU Options: (if using an MPC8xx CPU)
342 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
343 get_gclk_freq() cannot work
344 e.g. if there is no 32KHz
345 reference PIT/RTC clock
346 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
349 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
350 CONFIG_SYS_8xx_CPUCLK_MIN
351 CONFIG_SYS_8xx_CPUCLK_MAX
352 CONFIG_8xx_CPUCLK_DEFAULT
353 See doc/README.MPC866
355 CONFIG_SYS_MEASURE_CPUCLK
357 Define this to measure the actual CPU clock instead
358 of relying on the correctness of the configured
359 values. Mostly useful for board bringup to make sure
360 the PLL is locked at the intended frequency. Note
361 that this requires a (stable) reference clock (32 kHz
362 RTC clock or CONFIG_SYS_8XX_XIN)
364 CONFIG_SYS_DELAYED_ICACHE
366 Define this option if you want to enable the
367 ICache only when Code runs from RAM.
372 Specifies that the core is a 64-bit PowerPC implementation (implements
373 the "64" category of the Power ISA). This is necessary for ePAPR
374 compliance, among other possible reasons.
376 CONFIG_SYS_FSL_TBCLK_DIV
378 Defines the core time base clock divider ratio compared to the
379 system clock. On most PQ3 devices this is 8, on newer QorIQ
380 devices it can be 16 or 32. The ratio varies from SoC to Soc.
382 CONFIG_SYS_FSL_PCIE_COMPAT
384 Defines the string to utilize when trying to match PCIe device
385 tree nodes for the given platform.
387 CONFIG_SYS_PPC_E500_DEBUG_TLB
389 Enables a temporary TLB entry to be used during boot to work
390 around limitations in e500v1 and e500v2 external debugger
391 support. This reduces the portions of the boot code where
392 breakpoints and single stepping do not work. The value of this
393 symbol should be set to the TLB1 entry to be used for this
396 CONFIG_SYS_FSL_ERRATUM_A004510
398 Enables a workaround for erratum A004510. If set,
399 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
400 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
402 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
405 Defines one or two SoC revisions (low 8 bits of SVR)
406 for which the A004510 workaround should be applied.
408 The rest of SVR is either not relevant to the decision
409 of whether the erratum is present (e.g. p2040 versus
410 p2041) or is implied by the build target, which controls
411 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
413 See Freescale App Note 4493 for more information about
416 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
418 This is the value to write into CCSR offset 0x18600
419 according to the A004510 workaround.
421 - Generic CPU options:
422 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
424 Defines the endianess of the CPU. Implementation of those
425 values is arch specific.
427 - Intel Monahans options:
428 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
430 Defines the Monahans run mode to oscillator
431 ratio. Valid values are 8, 16, 24, 31. The core
432 frequency is this value multiplied by 13 MHz.
434 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
436 Defines the Monahans turbo mode to oscillator
437 ratio. Valid values are 1 (default if undefined) and
438 2. The core frequency as calculated above is multiplied
442 CONFIG_SYS_INIT_SP_OFFSET
444 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
445 pointer. This is needed for the temporary stack before
448 CONFIG_SYS_MIPS_CACHE_MODE
450 Cache operation mode for the MIPS CPU.
451 See also arch/mips/include/asm/mipsregs.h.
453 CONF_CM_CACHABLE_NO_WA
456 CONF_CM_CACHABLE_NONCOHERENT
460 CONF_CM_CACHABLE_ACCELERATED
462 CONFIG_SYS_XWAY_EBU_BOOTCFG
464 Special option for Lantiq XWAY SoCs for booting from NOR flash.
465 See also arch/mips/cpu/mips32/start.S.
467 CONFIG_XWAY_SWAP_BYTES
469 Enable compilation of tools/xway-swap-bytes needed for Lantiq
470 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
471 be swapped if a flash programmer is used.
474 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
476 Select high exception vectors of the ARM core, e.g., do not
477 clear the V bit of the c1 register of CP15.
479 CONFIG_SYS_THUMB_BUILD
481 Use this flag to build U-Boot using the Thumb instruction
482 set for ARM architectures. Thumb instruction set provides
483 better code density. For ARM architectures that support
484 Thumb2 this flag will result in Thumb2 code generated by
487 CONFIG_ARM_ERRATA_716044
488 CONFIG_ARM_ERRATA_742230
489 CONFIG_ARM_ERRATA_743622
490 CONFIG_ARM_ERRATA_751472
492 If set, the workarounds for these ARM errata are applied early
493 during U-Boot startup. Note that these options force the
494 workarounds to be applied; no CPU-type/version detection
495 exists, unlike the similar options in the Linux kernel. Do not
496 set these options unless they apply!
501 The frequency of the timer returned by get_timer().
502 get_timer() must operate in milliseconds and this CONFIG
503 option must be set to 1000.
505 - Linux Kernel Interface:
508 U-Boot stores all clock information in Hz
509 internally. For binary compatibility with older Linux
510 kernels (which expect the clocks passed in the
511 bd_info data to be in MHz) the environment variable
512 "clocks_in_mhz" can be defined so that U-Boot
513 converts clock data to MHZ before passing it to the
515 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
516 "clocks_in_mhz=1" is automatically included in the
519 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
521 When transferring memsize parameter to linux, some versions
522 expect it to be in bytes, others in MB.
523 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
527 New kernel versions are expecting firmware settings to be
528 passed using flattened device trees (based on open firmware
532 * New libfdt-based support
533 * Adds the "fdt" command
534 * The bootm command automatically updates the fdt
536 OF_CPU - The proper name of the cpus node (only required for
537 MPC512X and MPC5xxx based boards).
538 OF_SOC - The proper name of the soc node (only required for
539 MPC512X and MPC5xxx based boards).
540 OF_TBCLK - The timebase frequency.
541 OF_STDOUT_PATH - The path to the console device
543 boards with QUICC Engines require OF_QE to set UCC MAC
546 CONFIG_OF_BOARD_SETUP
548 Board code has addition modification that it wants to make
549 to the flat device tree before handing it off to the kernel
553 This define fills in the correct boot CPU in the boot
554 param header, the default value is zero if undefined.
558 U-Boot can detect if an IDE device is present or not.
559 If not, and this new config option is activated, U-Boot
560 removes the ATA node from the DTS before booting Linux,
561 so the Linux IDE driver does not probe the device and
562 crash. This is needed for buggy hardware (uc101) where
563 no pull down resistor is connected to the signal IDE5V_DD7.
565 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
567 This setting is mandatory for all boards that have only one
568 machine type and must be used to specify the machine type
569 number as it appears in the ARM machine registry
570 (see http://www.arm.linux.org.uk/developer/machines/).
571 Only boards that have multiple machine types supported
572 in a single configuration file and the machine type is
573 runtime discoverable, do not have to use this setting.
575 - vxWorks boot parameters:
577 bootvx constructs a valid bootline using the following
578 environments variables: bootfile, ipaddr, serverip, hostname.
579 It loads the vxWorks image pointed bootfile.
581 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
582 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
583 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
584 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
586 CONFIG_SYS_VXWORKS_ADD_PARAMS
588 Add it at the end of the bootline. E.g "u=username pw=secret"
590 Note: If a "bootargs" environment is defined, it will overwride
591 the defaults discussed just above.
593 - Cache Configuration:
594 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
595 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
596 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
598 - Cache Configuration for ARM:
599 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
601 CONFIG_SYS_PL310_BASE - Physical base address of PL310
602 controller register space
607 Define this if you want support for Amba PrimeCell PL010 UARTs.
611 Define this if you want support for Amba PrimeCell PL011 UARTs.
615 If you have Amba PrimeCell PL011 UARTs, set this variable to
616 the clock speed of the UARTs.
620 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
621 define this to a list of base addresses for each (supported)
622 port. See e.g. include/configs/versatile.h
624 CONFIG_PL011_SERIAL_RLCR
626 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
627 have separate receive and transmit line control registers. Set
628 this variable to initialize the extra register.
630 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
632 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
633 boot loader that has already initialized the UART. Define this
634 variable to flush the UART at init time.
638 Depending on board, define exactly one serial port
639 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
640 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
641 console by defining CONFIG_8xx_CONS_NONE
643 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
644 port routines must be defined elsewhere
645 (i.e. serial_init(), serial_getc(), ...)
648 Enables console device for a color framebuffer. Needs following
649 defines (cf. smiLynxEM, i8042)
650 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
652 VIDEO_HW_RECTFILL graphic chip supports
655 VIDEO_HW_BITBLT graphic chip supports
656 bit-blit (cf. smiLynxEM)
657 VIDEO_VISIBLE_COLS visible pixel columns
659 VIDEO_VISIBLE_ROWS visible pixel rows
660 VIDEO_PIXEL_SIZE bytes per pixel
661 VIDEO_DATA_FORMAT graphic data format
662 (0-5, cf. cfb_console.c)
663 VIDEO_FB_ADRS framebuffer address
664 VIDEO_KBD_INIT_FCT keyboard int fct
665 (i.e. i8042_kbd_init())
666 VIDEO_TSTC_FCT test char fct
668 VIDEO_GETC_FCT get char fct
670 CONFIG_CONSOLE_CURSOR cursor drawing on/off
671 (requires blink timer
673 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
674 CONFIG_CONSOLE_TIME display time/date info in
676 (requires CONFIG_CMD_DATE)
677 CONFIG_VIDEO_LOGO display Linux logo in
679 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
680 linux_logo.h for logo.
681 Requires CONFIG_VIDEO_LOGO
682 CONFIG_CONSOLE_EXTRA_INFO
683 additional board info beside
686 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
687 a limited number of ANSI escape sequences (cursor control,
688 erase functions and limited graphics rendition control).
690 When CONFIG_CFB_CONSOLE is defined, video console is
691 default i/o. Serial console can be forced with
692 environment 'console=serial'.
694 When CONFIG_SILENT_CONSOLE is defined, all console
695 messages (by U-Boot and Linux!) can be silenced with
696 the "silent" environment variable. See
697 doc/README.silent for more information.
700 CONFIG_BAUDRATE - in bps
701 Select one of the baudrates listed in
702 CONFIG_SYS_BAUDRATE_TABLE, see below.
703 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
705 - Console Rx buffer length
706 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
707 the maximum receive buffer length for the SMC.
708 This option is actual only for 82xx and 8xx possible.
709 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
710 must be defined, to setup the maximum idle timeout for
713 - Pre-Console Buffer:
714 Prior to the console being initialised (i.e. serial UART
715 initialised etc) all console output is silently discarded.
716 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
717 buffer any console messages prior to the console being
718 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
719 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
720 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
721 bytes are output before the console is initialised, the
722 earlier bytes are discarded.
724 'Sane' compilers will generate smaller code if
725 CONFIG_PRE_CON_BUF_SZ is a power of 2
727 - Safe printf() functions
728 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
729 the printf() functions. These are defined in
730 include/vsprintf.h and include snprintf(), vsnprintf() and
731 so on. Code size increase is approximately 300-500 bytes.
732 If this option is not given then these functions will
733 silently discard their buffer size argument - this means
734 you are not getting any overflow checking in this case.
736 - Boot Delay: CONFIG_BOOTDELAY - in seconds
737 Delay before automatically booting the default image;
738 set to -1 to disable autoboot.
739 set to -2 to autoboot with no delay and not check for abort
740 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
742 See doc/README.autoboot for these options that
743 work with CONFIG_BOOTDELAY. None are required.
744 CONFIG_BOOT_RETRY_TIME
745 CONFIG_BOOT_RETRY_MIN
746 CONFIG_AUTOBOOT_KEYED
747 CONFIG_AUTOBOOT_PROMPT
748 CONFIG_AUTOBOOT_DELAY_STR
749 CONFIG_AUTOBOOT_STOP_STR
750 CONFIG_AUTOBOOT_DELAY_STR2
751 CONFIG_AUTOBOOT_STOP_STR2
752 CONFIG_ZERO_BOOTDELAY_CHECK
753 CONFIG_RESET_TO_RETRY
757 Only needed when CONFIG_BOOTDELAY is enabled;
758 define a command string that is automatically executed
759 when no character is read on the console interface
760 within "Boot Delay" after reset.
763 This can be used to pass arguments to the bootm
764 command. The value of CONFIG_BOOTARGS goes into the
765 environment value "bootargs".
767 CONFIG_RAMBOOT and CONFIG_NFSBOOT
768 The value of these goes into the environment as
769 "ramboot" and "nfsboot" respectively, and can be used
770 as a convenience, when switching between booting from
776 When this option is #defined, the existence of the
777 environment variable "preboot" will be checked
778 immediately before starting the CONFIG_BOOTDELAY
779 countdown and/or running the auto-boot command resp.
780 entering interactive mode.
782 This feature is especially useful when "preboot" is
783 automatically generated or modified. For an example
784 see the LWMON board specific code: here "preboot" is
785 modified when the user holds down a certain
786 combination of keys on the (special) keyboard when
789 - Serial Download Echo Mode:
791 If defined to 1, all characters received during a
792 serial download (using the "loads" command) are
793 echoed back. This might be needed by some terminal
794 emulations (like "cu"), but may as well just take
795 time on others. This setting #define's the initial
796 value of the "loads_echo" environment variable.
798 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
800 Select one of the baudrates listed in
801 CONFIG_SYS_BAUDRATE_TABLE, see below.
804 Monitor commands can be included or excluded
805 from the build by using the #include files
806 <config_cmd_all.h> and #undef'ing unwanted
807 commands, or using <config_cmd_default.h>
808 and augmenting with additional #define's
811 The default command configuration includes all commands
812 except those marked below with a "*".
814 CONFIG_CMD_ASKENV * ask for env variable
815 CONFIG_CMD_BDI bdinfo
816 CONFIG_CMD_BEDBUG * Include BedBug Debugger
817 CONFIG_CMD_BMP * BMP support
818 CONFIG_CMD_BSP * Board specific commands
819 CONFIG_CMD_BOOTD bootd
820 CONFIG_CMD_CACHE * icache, dcache
821 CONFIG_CMD_CONSOLE coninfo
822 CONFIG_CMD_CRC32 * crc32
823 CONFIG_CMD_DATE * support for RTC, date/time...
824 CONFIG_CMD_DHCP * DHCP support
825 CONFIG_CMD_DIAG * Diagnostics
826 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
827 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
828 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
829 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
830 CONFIG_CMD_DTT * Digital Therm and Thermostat
831 CONFIG_CMD_ECHO echo arguments
832 CONFIG_CMD_EDITENV edit env variable
833 CONFIG_CMD_EEPROM * EEPROM read/write support
834 CONFIG_CMD_ELF * bootelf, bootvx
835 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
836 CONFIG_CMD_ENV_FLAGS * display details about env flags
837 CONFIG_CMD_EXPORTENV * export the environment
838 CONFIG_CMD_EXT2 * ext2 command support
839 CONFIG_CMD_EXT4 * ext4 command support
840 CONFIG_CMD_SAVEENV saveenv
841 CONFIG_CMD_FDC * Floppy Disk Support
842 CONFIG_CMD_FAT * FAT command support
843 CONFIG_CMD_FDOS * Dos diskette Support
844 CONFIG_CMD_FLASH flinfo, erase, protect
845 CONFIG_CMD_FPGA FPGA device initialization support
846 CONFIG_CMD_FUSE Device fuse support
847 CONFIG_CMD_GETTIME * Get time since boot
848 CONFIG_CMD_GO * the 'go' command (exec code)
849 CONFIG_CMD_GREPENV * search environment
850 CONFIG_CMD_HASH * calculate hash / digest
851 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
852 CONFIG_CMD_I2C * I2C serial bus support
853 CONFIG_CMD_IDE * IDE harddisk support
854 CONFIG_CMD_IMI iminfo
855 CONFIG_CMD_IMLS List all images found in NOR flash
856 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
857 CONFIG_CMD_IMMAP * IMMR dump support
858 CONFIG_CMD_IMPORTENV * import an environment
859 CONFIG_CMD_INI * import data from an ini file into the env
860 CONFIG_CMD_IRQ * irqinfo
861 CONFIG_CMD_ITEST Integer/string test of 2 values
862 CONFIG_CMD_JFFS2 * JFFS2 Support
863 CONFIG_CMD_KGDB * kgdb
864 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
865 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
867 CONFIG_CMD_LOADB loadb
868 CONFIG_CMD_LOADS loads
869 CONFIG_CMD_MD5SUM print md5 message digest
870 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
871 CONFIG_CMD_MEMINFO * Display detailed memory information
872 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
874 CONFIG_CMD_MEMTEST mtest
875 CONFIG_CMD_MISC Misc functions like sleep etc
876 CONFIG_CMD_MMC * MMC memory mapped support
877 CONFIG_CMD_MII * MII utility commands
878 CONFIG_CMD_MTDPARTS * MTD partition support
879 CONFIG_CMD_NAND * NAND support
880 CONFIG_CMD_NET bootp, tftpboot, rarpboot
881 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
882 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
883 CONFIG_CMD_PCI * pciinfo
884 CONFIG_CMD_PCMCIA * PCMCIA support
885 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
887 CONFIG_CMD_PORTIO * Port I/O
888 CONFIG_CMD_READ * Read raw data from partition
889 CONFIG_CMD_REGINFO * Register dump
890 CONFIG_CMD_RUN run command in env variable
891 CONFIG_CMD_SANDBOX * sb command to access sandbox features
892 CONFIG_CMD_SAVES * save S record dump
893 CONFIG_CMD_SCSI * SCSI Support
894 CONFIG_CMD_SDRAM * print SDRAM configuration information
895 (requires CONFIG_CMD_I2C)
896 CONFIG_CMD_SETGETDCR Support for DCR Register access
898 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
899 CONFIG_CMD_SHA1SUM print sha1 memory digest
900 (requires CONFIG_CMD_MEMORY)
901 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
902 CONFIG_CMD_SOURCE "source" command Support
903 CONFIG_CMD_SPI * SPI serial bus support
904 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
905 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
906 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
907 CONFIG_CMD_TIMER * access to the system tick timer
908 CONFIG_CMD_USB * USB support
909 CONFIG_CMD_CDP * Cisco Discover Protocol support
910 CONFIG_CMD_MFSL * Microblaze FSL support
913 EXAMPLE: If you want all functions except of network
914 support you can write:
916 #include "config_cmd_all.h"
917 #undef CONFIG_CMD_NET
920 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
922 Note: Don't enable the "icache" and "dcache" commands
923 (configuration option CONFIG_CMD_CACHE) unless you know
924 what you (and your U-Boot users) are doing. Data
925 cache cannot be enabled on systems like the 8xx or
926 8260 (where accesses to the IMMR region must be
927 uncached), and it cannot be disabled on all other
928 systems where we (mis-) use the data cache to hold an
929 initial stack and some data.
932 XXX - this list needs to get updated!
934 - Regular expression support:
936 If this variable is defined, U-Boot is linked against
937 the SLRE (Super Light Regular Expression) library,
938 which adds regex support to some commands, as for
939 example "env grep" and "setexpr".
943 If this variable is defined, U-Boot will use a device tree
944 to configure its devices, instead of relying on statically
945 compiled #defines in the board file. This option is
946 experimental and only available on a few boards. The device
947 tree is available in the global data as gd->fdt_blob.
949 U-Boot needs to get its device tree from somewhere. This can
950 be done using one of the two options below:
953 If this variable is defined, U-Boot will embed a device tree
954 binary in its image. This device tree file should be in the
955 board directory and called <soc>-<board>.dts. The binary file
956 is then picked up in board_init_f() and made available through
957 the global data structure as gd->blob.
960 If this variable is defined, U-Boot will build a device tree
961 binary. It will be called u-boot.dtb. Architecture-specific
962 code will locate it at run-time. Generally this works by:
964 cat u-boot.bin u-boot.dtb >image.bin
966 and in fact, U-Boot does this for you, creating a file called
967 u-boot-dtb.bin which is useful in the common case. You can
968 still use the individual files if you need something more
973 If this variable is defined, it enables watchdog
974 support for the SoC. There must be support in the SoC
975 specific code for a watchdog. For the 8xx and 8260
976 CPUs, the SIU Watchdog feature is enabled in the SYPCR
977 register. When supported for a specific SoC is
978 available, then no further board specific code should
982 When using a watchdog circuitry external to the used
983 SoC, then define this variable and provide board
984 specific code for the "hw_watchdog_reset" function.
987 CONFIG_VERSION_VARIABLE
988 If this variable is defined, an environment variable
989 named "ver" is created by U-Boot showing the U-Boot
990 version as printed by the "version" command.
991 Any change to this variable will be reverted at the
996 When CONFIG_CMD_DATE is selected, the type of the RTC
997 has to be selected, too. Define exactly one of the
1000 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1001 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1002 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1003 CONFIG_RTC_MC146818 - use MC146818 RTC
1004 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1005 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1006 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1007 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1008 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1009 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1010 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1011 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1014 Note that if the RTC uses I2C, then the I2C interface
1015 must also be configured. See I2C Support, below.
1018 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1019 CONFIG_PCA953X_INFO - enable pca953x info command
1021 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1022 chip-ngpio pairs that tell the PCA953X driver the number of
1023 pins supported by a particular chip.
1025 Note that if the GPIO device uses I2C, then the I2C interface
1026 must also be configured. See I2C Support, below.
1028 - Timestamp Support:
1030 When CONFIG_TIMESTAMP is selected, the timestamp
1031 (date and time) of an image is printed by image
1032 commands like bootm or iminfo. This option is
1033 automatically enabled when you select CONFIG_CMD_DATE .
1035 - Partition Labels (disklabels) Supported:
1036 Zero or more of the following:
1037 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1038 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1039 Intel architecture, USB sticks, etc.
1040 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1041 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1042 bootloader. Note 2TB partition limit; see
1044 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1046 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1047 CONFIG_CMD_SCSI) you must configure support for at
1048 least one non-MTD partition type as well.
1051 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1052 board configurations files but used nowhere!
1054 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1055 be performed by calling the function
1056 ide_set_reset(int reset)
1057 which has to be defined in a board specific file
1062 Set this to enable ATAPI support.
1067 Set this to enable support for disks larger than 137GB
1068 Also look at CONFIG_SYS_64BIT_LBA.
1069 Whithout these , LBA48 support uses 32bit variables and will 'only'
1070 support disks up to 2.1TB.
1072 CONFIG_SYS_64BIT_LBA:
1073 When enabled, makes the IDE subsystem use 64bit sector addresses.
1077 At the moment only there is only support for the
1078 SYM53C8XX SCSI controller; define
1079 CONFIG_SCSI_SYM53C8XX to enable it.
1081 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1082 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1083 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1084 maximum numbers of LUNs, SCSI ID's and target
1086 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1088 The environment variable 'scsidevs' is set to the number of
1089 SCSI devices found during the last scan.
1091 - NETWORK Support (PCI):
1093 Support for Intel 8254x/8257x gigabit chips.
1096 Utility code for direct access to the SPI bus on Intel 8257x.
1097 This does not do anything useful unless you set at least one
1098 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1100 CONFIG_E1000_SPI_GENERIC
1101 Allow generic access to the SPI bus on the Intel 8257x, for
1102 example with the "sspi" command.
1105 Management command for E1000 devices. When used on devices
1106 with SPI support you can reprogram the EEPROM from U-Boot.
1108 CONFIG_E1000_FALLBACK_MAC
1109 default MAC for empty EEPROM after production.
1112 Support for Intel 82557/82559/82559ER chips.
1113 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1114 write routine for first time initialisation.
1117 Support for Digital 2114x chips.
1118 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1119 modem chip initialisation (KS8761/QS6611).
1122 Support for National dp83815 chips.
1125 Support for National dp8382[01] gigabit chips.
1127 - NETWORK Support (other):
1129 CONFIG_DRIVER_AT91EMAC
1130 Support for AT91RM9200 EMAC.
1133 Define this to use reduced MII inteface
1135 CONFIG_DRIVER_AT91EMAC_QUIET
1136 If this defined, the driver is quiet.
1137 The driver doen't show link status messages.
1139 CONFIG_CALXEDA_XGMAC
1140 Support for the Calxeda XGMAC device
1143 Support for SMSC's LAN91C96 chips.
1145 CONFIG_LAN91C96_BASE
1146 Define this to hold the physical address
1147 of the LAN91C96's I/O space
1149 CONFIG_LAN91C96_USE_32_BIT
1150 Define this to enable 32 bit addressing
1153 Support for SMSC's LAN91C111 chip
1155 CONFIG_SMC91111_BASE
1156 Define this to hold the physical address
1157 of the device (I/O space)
1159 CONFIG_SMC_USE_32_BIT
1160 Define this if data bus is 32 bits
1162 CONFIG_SMC_USE_IOFUNCS
1163 Define this to use i/o functions instead of macros
1164 (some hardware wont work with macros)
1166 CONFIG_DRIVER_TI_EMAC
1167 Support for davinci emac
1169 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1170 Define this if you have more then 3 PHYs.
1173 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1175 CONFIG_FTGMAC100_EGIGA
1176 Define this to use GE link update with gigabit PHY.
1177 Define this if FTGMAC100 is connected to gigabit PHY.
1178 If your system has 10/100 PHY only, it might not occur
1179 wrong behavior. Because PHY usually return timeout or
1180 useless data when polling gigabit status and gigabit
1181 control registers. This behavior won't affect the
1182 correctnessof 10/100 link speed update.
1185 Support for SMSC's LAN911x and LAN921x chips
1188 Define this to hold the physical address
1189 of the device (I/O space)
1191 CONFIG_SMC911X_32_BIT
1192 Define this if data bus is 32 bits
1194 CONFIG_SMC911X_16_BIT
1195 Define this if data bus is 16 bits. If your processor
1196 automatically converts one 32 bit word to two 16 bit
1197 words you may also try CONFIG_SMC911X_32_BIT.
1200 Support for Renesas on-chip Ethernet controller
1202 CONFIG_SH_ETHER_USE_PORT
1203 Define the number of ports to be used
1205 CONFIG_SH_ETHER_PHY_ADDR
1206 Define the ETH PHY's address
1208 CONFIG_SH_ETHER_CACHE_WRITEBACK
1209 If this option is set, the driver enables cache flush.
1213 Support TPM devices.
1216 Support for i2c bus TPM devices. Only one device
1217 per system is supported at this time.
1219 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1220 Define the the i2c bus number for the TPM device
1222 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1223 Define the TPM's address on the i2c bus
1225 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1226 Define the burst count bytes upper limit
1229 Support for generic parallel port TPM devices. Only one device
1230 per system is supported at this time.
1232 CONFIG_TPM_TIS_BASE_ADDRESS
1233 Base address where the generic TPM device is mapped
1234 to. Contemporary x86 systems usually map it at
1238 At the moment only the UHCI host controller is
1239 supported (PIP405, MIP405, MPC5200); define
1240 CONFIG_USB_UHCI to enable it.
1241 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1242 and define CONFIG_USB_STORAGE to enable the USB
1245 Supported are USB Keyboards and USB Floppy drives
1247 MPC5200 USB requires additional defines:
1249 for 528 MHz Clock: 0x0001bbbb
1253 for differential drivers: 0x00001000
1254 for single ended drivers: 0x00005000
1255 for differential drivers on PSC3: 0x00000100
1256 for single ended drivers on PSC3: 0x00004100
1257 CONFIG_SYS_USB_EVENT_POLL
1258 May be defined to allow interrupt polling
1259 instead of using asynchronous interrupts
1261 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1262 txfilltuning field in the EHCI controller on reset.
1265 Define the below if you wish to use the USB console.
1266 Once firmware is rebuilt from a serial console issue the
1267 command "setenv stdin usbtty; setenv stdout usbtty" and
1268 attach your USB cable. The Unix command "dmesg" should print
1269 it has found a new device. The environment variable usbtty
1270 can be set to gserial or cdc_acm to enable your device to
1271 appear to a USB host as a Linux gserial device or a
1272 Common Device Class Abstract Control Model serial device.
1273 If you select usbtty = gserial you should be able to enumerate
1275 # modprobe usbserial vendor=0xVendorID product=0xProductID
1276 else if using cdc_acm, simply setting the environment
1277 variable usbtty to be cdc_acm should suffice. The following
1278 might be defined in YourBoardName.h
1281 Define this to build a UDC device
1284 Define this to have a tty type of device available to
1285 talk to the UDC device
1288 Define this to enable the high speed support for usb
1289 device and usbtty. If this feature is enabled, a routine
1290 int is_usbd_high_speed(void)
1291 also needs to be defined by the driver to dynamically poll
1292 whether the enumeration has succeded at high speed or full
1295 CONFIG_SYS_CONSOLE_IS_IN_ENV
1296 Define this if you want stdin, stdout &/or stderr to
1300 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1301 Derive USB clock from external clock "blah"
1302 - CONFIG_SYS_USB_EXTC_CLK 0x02
1304 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1305 Derive USB clock from brgclk
1306 - CONFIG_SYS_USB_BRG_CLK 0x04
1308 If you have a USB-IF assigned VendorID then you may wish to
1309 define your own vendor specific values either in BoardName.h
1310 or directly in usbd_vendor_info.h. If you don't define
1311 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1312 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1313 should pretend to be a Linux device to it's target host.
1315 CONFIG_USBD_MANUFACTURER
1316 Define this string as the name of your company for
1317 - CONFIG_USBD_MANUFACTURER "my company"
1319 CONFIG_USBD_PRODUCT_NAME
1320 Define this string as the name of your product
1321 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1323 CONFIG_USBD_VENDORID
1324 Define this as your assigned Vendor ID from the USB
1325 Implementors Forum. This *must* be a genuine Vendor ID
1326 to avoid polluting the USB namespace.
1327 - CONFIG_USBD_VENDORID 0xFFFF
1329 CONFIG_USBD_PRODUCTID
1330 Define this as the unique Product ID
1332 - CONFIG_USBD_PRODUCTID 0xFFFF
1334 - ULPI Layer Support:
1335 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1336 the generic ULPI layer. The generic layer accesses the ULPI PHY
1337 via the platform viewport, so you need both the genric layer and
1338 the viewport enabled. Currently only Chipidea/ARC based
1339 viewport is supported.
1340 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1341 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1342 If your ULPI phy needs a different reference clock than the
1343 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1344 the appropriate value in Hz.
1347 The MMC controller on the Intel PXA is supported. To
1348 enable this define CONFIG_MMC. The MMC can be
1349 accessed from the boot prompt by mapping the device
1350 to physical memory similar to flash. Command line is
1351 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1352 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1355 Support for Renesas on-chip MMCIF controller
1357 CONFIG_SH_MMCIF_ADDR
1358 Define the base address of MMCIF registers
1361 Define the clock frequency for MMCIF
1363 - USB Device Firmware Update (DFU) class support:
1365 This enables the USB portion of the DFU USB class
1368 This enables the command "dfu" which is used to have
1369 U-Boot create a DFU class device via USB. This command
1370 requires that the "dfu_alt_info" environment variable be
1371 set and define the alt settings to expose to the host.
1374 This enables support for exposing (e)MMC devices via DFU.
1377 This enables support for exposing NAND devices via DFU.
1379 CONFIG_SYS_DFU_MAX_FILE_SIZE
1380 When updating files rather than the raw storage device,
1381 we use a static buffer to copy the file into and then write
1382 the buffer once we've been given the whole file. Define
1383 this to the maximum filesize (in bytes) for the buffer.
1384 Default is 4 MiB if undefined.
1386 - Journaling Flash filesystem support:
1387 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1388 CONFIG_JFFS2_NAND_DEV
1389 Define these for a default partition on a NAND device
1391 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1392 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1393 Define these for a default partition on a NOR device
1395 CONFIG_SYS_JFFS_CUSTOM_PART
1396 Define this to create an own partition. You have to provide a
1397 function struct part_info* jffs2_part_info(int part_num)
1399 If you define only one JFFS2 partition you may also want to
1400 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1401 to disable the command chpart. This is the default when you
1402 have not defined a custom partition
1404 - FAT(File Allocation Table) filesystem write function support:
1407 Define this to enable support for saving memory data as a
1408 file in FAT formatted partition.
1410 This will also enable the command "fatwrite" enabling the
1411 user to write files to FAT.
1413 CBFS (Coreboot Filesystem) support
1416 Define this to enable support for reading from a Coreboot
1417 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1423 Define this to enable standard (PC-Style) keyboard
1427 Standard PC keyboard driver with US (is default) and
1428 GERMAN key layout (switch via environment 'keymap=de') support.
1429 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1430 for cfb_console. Supports cursor blinking.
1435 Define this to enable video support (for output to
1438 CONFIG_VIDEO_CT69000
1440 Enable Chips & Technologies 69000 Video chip
1442 CONFIG_VIDEO_SMI_LYNXEM
1443 Enable Silicon Motion SMI 712/710/810 Video chip. The
1444 video output is selected via environment 'videoout'
1445 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1448 For the CT69000 and SMI_LYNXEM drivers, videomode is
1449 selected via environment 'videomode'. Two different ways
1451 - "videomode=num" 'num' is a standard LiLo mode numbers.
1452 Following standard modes are supported (* is default):
1454 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1455 -------------+---------------------------------------------
1456 8 bits | 0x301* 0x303 0x305 0x161 0x307
1457 15 bits | 0x310 0x313 0x316 0x162 0x319
1458 16 bits | 0x311 0x314 0x317 0x163 0x31A
1459 24 bits | 0x312 0x315 0x318 ? 0x31B
1460 -------------+---------------------------------------------
1461 (i.e. setenv videomode 317; saveenv; reset;)
1463 - "videomode=bootargs" all the video parameters are parsed
1464 from the bootargs. (See drivers/video/videomodes.c)
1467 CONFIG_VIDEO_SED13806
1468 Enable Epson SED13806 driver. This driver supports 8bpp
1469 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1470 or CONFIG_VIDEO_SED13806_16BPP
1473 Enable the Freescale DIU video driver. Reference boards for
1474 SOCs that have a DIU should define this macro to enable DIU
1475 support, and should also define these other macros:
1481 CONFIG_VIDEO_SW_CURSOR
1482 CONFIG_VGA_AS_SINGLE_DEVICE
1484 CONFIG_VIDEO_BMP_LOGO
1486 The DIU driver will look for the 'video-mode' environment
1487 variable, and if defined, enable the DIU as a console during
1488 boot. See the documentation file README.video for a
1489 description of this variable.
1493 Enable the VGA video / BIOS for x86. The alternative if you
1494 are using coreboot is to use the coreboot frame buffer
1501 Define this to enable a custom keyboard support.
1502 This simply calls drv_keyboard_init() which must be
1503 defined in your board-specific files.
1504 The only board using this so far is RBC823.
1506 - LCD Support: CONFIG_LCD
1508 Define this to enable LCD support (for output to LCD
1509 display); also select one of the supported displays
1510 by defining one of these:
1514 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1516 CONFIG_NEC_NL6448AC33:
1518 NEC NL6448AC33-18. Active, color, single scan.
1520 CONFIG_NEC_NL6448BC20
1522 NEC NL6448BC20-08. 6.5", 640x480.
1523 Active, color, single scan.
1525 CONFIG_NEC_NL6448BC33_54
1527 NEC NL6448BC33-54. 10.4", 640x480.
1528 Active, color, single scan.
1532 Sharp 320x240. Active, color, single scan.
1533 It isn't 16x9, and I am not sure what it is.
1535 CONFIG_SHARP_LQ64D341
1537 Sharp LQ64D341 display, 640x480.
1538 Active, color, single scan.
1542 HLD1045 display, 640x480.
1543 Active, color, single scan.
1547 Optrex CBL50840-2 NF-FW 99 22 M5
1549 Hitachi LMG6912RPFC-00T
1553 320x240. Black & white.
1555 Normally display is black on white background; define
1556 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1558 CONFIG_LCD_ALIGNMENT
1560 Normally the LCD is page-aligned (tyically 4KB). If this is
1561 defined then the LCD will be aligned to this value instead.
1562 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1563 here, since it is cheaper to change data cache settings on
1564 a per-section basis.
1566 CONFIG_CONSOLE_SCROLL_LINES
1568 When the console need to be scrolled, this is the number of
1569 lines to scroll by. It defaults to 1. Increasing this makes
1570 the console jump but can help speed up operation when scrolling
1575 Support drawing of RLE8-compressed bitmaps on the LCD.
1579 Enables an 'i2c edid' command which can read EDID
1580 information over I2C from an attached LCD display.
1582 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1584 If this option is set, the environment is checked for
1585 a variable "splashimage". If found, the usual display
1586 of logo, copyright and system information on the LCD
1587 is suppressed and the BMP image at the address
1588 specified in "splashimage" is loaded instead. The
1589 console is redirected to the "nulldev", too. This
1590 allows for a "silent" boot where a splash screen is
1591 loaded very quickly after power-on.
1593 CONFIG_SPLASHIMAGE_GUARD
1595 If this option is set, then U-Boot will prevent the environment
1596 variable "splashimage" from being set to a problematic address
1597 (see README.displaying-bmps and README.arm-unaligned-accesses).
1598 This option is useful for targets where, due to alignment
1599 restrictions, an improperly aligned BMP image will cause a data
1600 abort. If you think you will not have problems with unaligned
1601 accesses (for example because your toolchain prevents them)
1602 there is no need to set this option.
1604 CONFIG_SPLASH_SCREEN_ALIGN
1606 If this option is set the splash image can be freely positioned
1607 on the screen. Environment variable "splashpos" specifies the
1608 position as "x,y". If a positive number is given it is used as
1609 number of pixel from left/top. If a negative number is given it
1610 is used as number of pixel from right/bottom. You can also
1611 specify 'm' for centering the image.
1614 setenv splashpos m,m
1615 => image at center of screen
1617 setenv splashpos 30,20
1618 => image at x = 30 and y = 20
1620 setenv splashpos -10,m
1621 => vertically centered image
1622 at x = dspWidth - bmpWidth - 9
1624 CONFIG_SPLASH_SCREEN_PREPARE
1626 If this option is set then the board_splash_screen_prepare()
1627 function, which must be defined in your code, is called as part
1628 of the splash screen display sequence. It gives the board an
1629 opportunity to prepare the splash image data before it is
1630 processed and sent to the frame buffer by U-Boot.
1632 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1634 If this option is set, additionally to standard BMP
1635 images, gzipped BMP images can be displayed via the
1636 splashscreen support or the bmp command.
1638 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1640 If this option is set, 8-bit RLE compressed BMP images
1641 can be displayed via the splashscreen support or the
1644 - Do compresssing for memory range:
1647 If this option is set, it would use zlib deflate method
1648 to compress the specified memory at its best effort.
1650 - Compression support:
1653 If this option is set, support for bzip2 compressed
1654 images is included. If not, only uncompressed and gzip
1655 compressed images are supported.
1657 NOTE: the bzip2 algorithm requires a lot of RAM, so
1658 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1663 If this option is set, support for lzma compressed
1666 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1667 requires an amount of dynamic memory that is given by the
1670 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1672 Where lc and lp stand for, respectively, Literal context bits
1673 and Literal pos bits.
1675 This value is upper-bounded by 14MB in the worst case. Anyway,
1676 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1677 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1678 a very small buffer.
1680 Use the lzmainfo tool to determinate the lc and lp values and
1681 then calculate the amount of needed dynamic memory (ensuring
1682 the appropriate CONFIG_SYS_MALLOC_LEN value).
1687 The address of PHY on MII bus.
1689 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1691 The clock frequency of the MII bus
1695 If this option is set, support for speed/duplex
1696 detection of gigabit PHY is included.
1698 CONFIG_PHY_RESET_DELAY
1700 Some PHY like Intel LXT971A need extra delay after
1701 reset before any MII register access is possible.
1702 For such PHY, set this option to the usec delay
1703 required. (minimum 300usec for LXT971A)
1705 CONFIG_PHY_CMD_DELAY (ppc4xx)
1707 Some PHY like Intel LXT971A need extra delay after
1708 command issued before MII status register can be read
1718 Define a default value for Ethernet address to use
1719 for the respective Ethernet interface, in case this
1720 is not determined automatically.
1725 Define a default value for the IP address to use for
1726 the default Ethernet interface, in case this is not
1727 determined through e.g. bootp.
1728 (Environment variable "ipaddr")
1730 - Server IP address:
1733 Defines a default value for the IP address of a TFTP
1734 server to contact when using the "tftboot" command.
1735 (Environment variable "serverip")
1737 CONFIG_KEEP_SERVERADDR
1739 Keeps the server's MAC address, in the env 'serveraddr'
1740 for passing to bootargs (like Linux's netconsole option)
1742 - Gateway IP address:
1745 Defines a default value for the IP address of the
1746 default router where packets to other networks are
1748 (Environment variable "gatewayip")
1753 Defines a default value for the subnet mask (or
1754 routing prefix) which is used to determine if an IP
1755 address belongs to the local subnet or needs to be
1756 forwarded through a router.
1757 (Environment variable "netmask")
1759 - Multicast TFTP Mode:
1762 Defines whether you want to support multicast TFTP as per
1763 rfc-2090; for example to work with atftp. Lets lots of targets
1764 tftp down the same boot image concurrently. Note: the Ethernet
1765 driver in use must provide a function: mcast() to join/leave a
1768 - BOOTP Recovery Mode:
1769 CONFIG_BOOTP_RANDOM_DELAY
1771 If you have many targets in a network that try to
1772 boot using BOOTP, you may want to avoid that all
1773 systems send out BOOTP requests at precisely the same
1774 moment (which would happen for instance at recovery
1775 from a power failure, when all systems will try to
1776 boot, thus flooding the BOOTP server. Defining
1777 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1778 inserted before sending out BOOTP requests. The
1779 following delays are inserted then:
1781 1st BOOTP request: delay 0 ... 1 sec
1782 2nd BOOTP request: delay 0 ... 2 sec
1783 3rd BOOTP request: delay 0 ... 4 sec
1785 BOOTP requests: delay 0 ... 8 sec
1787 - DHCP Advanced Options:
1788 You can fine tune the DHCP functionality by defining
1789 CONFIG_BOOTP_* symbols:
1791 CONFIG_BOOTP_SUBNETMASK
1792 CONFIG_BOOTP_GATEWAY
1793 CONFIG_BOOTP_HOSTNAME
1794 CONFIG_BOOTP_NISDOMAIN
1795 CONFIG_BOOTP_BOOTPATH
1796 CONFIG_BOOTP_BOOTFILESIZE
1799 CONFIG_BOOTP_SEND_HOSTNAME
1800 CONFIG_BOOTP_NTPSERVER
1801 CONFIG_BOOTP_TIMEOFFSET
1802 CONFIG_BOOTP_VENDOREX
1803 CONFIG_BOOTP_MAY_FAIL
1805 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1806 environment variable, not the BOOTP server.
1808 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1809 after the configured retry count, the call will fail
1810 instead of starting over. This can be used to fail over
1811 to Link-local IP address configuration if the DHCP server
1814 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1815 serverip from a DHCP server, it is possible that more
1816 than one DNS serverip is offered to the client.
1817 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1818 serverip will be stored in the additional environment
1819 variable "dnsip2". The first DNS serverip is always
1820 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1823 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1824 to do a dynamic update of a DNS server. To do this, they
1825 need the hostname of the DHCP requester.
1826 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1827 of the "hostname" environment variable is passed as
1828 option 12 to the DHCP server.
1830 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1832 A 32bit value in microseconds for a delay between
1833 receiving a "DHCP Offer" and sending the "DHCP Request".
1834 This fixes a problem with certain DHCP servers that don't
1835 respond 100% of the time to a "DHCP request". E.g. On an
1836 AT91RM9200 processor running at 180MHz, this delay needed
1837 to be *at least* 15,000 usec before a Windows Server 2003
1838 DHCP server would reply 100% of the time. I recommend at
1839 least 50,000 usec to be safe. The alternative is to hope
1840 that one of the retries will be successful but note that
1841 the DHCP timeout and retry process takes a longer than
1844 - Link-local IP address negotiation:
1845 Negotiate with other link-local clients on the local network
1846 for an address that doesn't require explicit configuration.
1847 This is especially useful if a DHCP server cannot be guaranteed
1848 to exist in all environments that the device must operate.
1850 See doc/README.link-local for more information.
1853 CONFIG_CDP_DEVICE_ID
1855 The device id used in CDP trigger frames.
1857 CONFIG_CDP_DEVICE_ID_PREFIX
1859 A two character string which is prefixed to the MAC address
1864 A printf format string which contains the ascii name of
1865 the port. Normally is set to "eth%d" which sets
1866 eth0 for the first Ethernet, eth1 for the second etc.
1868 CONFIG_CDP_CAPABILITIES
1870 A 32bit integer which indicates the device capabilities;
1871 0x00000010 for a normal host which does not forwards.
1875 An ascii string containing the version of the software.
1879 An ascii string containing the name of the platform.
1883 A 32bit integer sent on the trigger.
1885 CONFIG_CDP_POWER_CONSUMPTION
1887 A 16bit integer containing the power consumption of the
1888 device in .1 of milliwatts.
1890 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1892 A byte containing the id of the VLAN.
1894 - Status LED: CONFIG_STATUS_LED
1896 Several configurations allow to display the current
1897 status using a LED. For instance, the LED will blink
1898 fast while running U-Boot code, stop blinking as
1899 soon as a reply to a BOOTP request was received, and
1900 start blinking slow once the Linux kernel is running
1901 (supported by a status LED driver in the Linux
1902 kernel). Defining CONFIG_STATUS_LED enables this
1905 - CAN Support: CONFIG_CAN_DRIVER
1907 Defining CONFIG_CAN_DRIVER enables CAN driver support
1908 on those systems that support this (optional)
1909 feature, like the TQM8xxL modules.
1911 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1913 These enable I2C serial bus commands. Defining either of
1914 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1915 include the appropriate I2C driver for the selected CPU.
1917 This will allow you to use i2c commands at the u-boot
1918 command line (as long as you set CONFIG_CMD_I2C in
1919 CONFIG_COMMANDS) and communicate with i2c based realtime
1920 clock chips. See common/cmd_i2c.c for a description of the
1921 command line interface.
1923 CONFIG_HARD_I2C selects a hardware I2C controller.
1925 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1926 bit-banging) driver instead of CPM or similar hardware
1929 There are several other quantities that must also be
1930 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1932 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1933 to be the frequency (in Hz) at which you wish your i2c bus
1934 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1935 the CPU's i2c node address).
1937 Now, the u-boot i2c code for the mpc8xx
1938 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1939 and so its address should therefore be cleared to 0 (See,
1940 eg, MPC823e User's Manual p.16-473). So, set
1941 CONFIG_SYS_I2C_SLAVE to 0.
1943 CONFIG_SYS_I2C_INIT_MPC5XXX
1945 When a board is reset during an i2c bus transfer
1946 chips might think that the current transfer is still
1947 in progress. Reset the slave devices by sending start
1948 commands until the slave device responds.
1950 That's all that's required for CONFIG_HARD_I2C.
1952 If you use the software i2c interface (CONFIG_SOFT_I2C)
1953 then the following macros need to be defined (examples are
1954 from include/configs/lwmon.h):
1958 (Optional). Any commands necessary to enable the I2C
1959 controller or configure ports.
1961 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1965 (Only for MPC8260 CPU). The I/O port to use (the code
1966 assumes both bits are on the same port). Valid values
1967 are 0..3 for ports A..D.
1971 The code necessary to make the I2C data line active
1972 (driven). If the data line is open collector, this
1975 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1979 The code necessary to make the I2C data line tri-stated
1980 (inactive). If the data line is open collector, this
1983 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1987 Code that returns true if the I2C data line is high,
1990 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1994 If <bit> is true, sets the I2C data line high. If it
1995 is false, it clears it (low).
1997 eg: #define I2C_SDA(bit) \
1998 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1999 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2003 If <bit> is true, sets the I2C clock line high. If it
2004 is false, it clears it (low).
2006 eg: #define I2C_SCL(bit) \
2007 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2008 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2012 This delay is invoked four times per clock cycle so this
2013 controls the rate of data transfer. The data rate thus
2014 is 1 / (I2C_DELAY * 4). Often defined to be something
2017 #define I2C_DELAY udelay(2)
2019 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2021 If your arch supports the generic GPIO framework (asm/gpio.h),
2022 then you may alternatively define the two GPIOs that are to be
2023 used as SCL / SDA. Any of the previous I2C_xxx macros will
2024 have GPIO-based defaults assigned to them as appropriate.
2026 You should define these to the GPIO value as given directly to
2027 the generic GPIO functions.
2029 CONFIG_SYS_I2C_INIT_BOARD
2031 When a board is reset during an i2c bus transfer
2032 chips might think that the current transfer is still
2033 in progress. On some boards it is possible to access
2034 the i2c SCLK line directly, either by using the
2035 processor pin as a GPIO or by having a second pin
2036 connected to the bus. If this option is defined a
2037 custom i2c_init_board() routine in boards/xxx/board.c
2038 is run early in the boot sequence.
2040 CONFIG_SYS_I2C_BOARD_LATE_INIT
2042 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2043 defined a custom i2c_board_late_init() routine in
2044 boards/xxx/board.c is run AFTER the operations in i2c_init()
2045 is completed. This callpoint can be used to unreset i2c bus
2046 using CPU i2c controller register accesses for CPUs whose i2c
2047 controller provide such a method. It is called at the end of
2048 i2c_init() to allow i2c_init operations to setup the i2c bus
2049 controller on the CPU (e.g. setting bus speed & slave address).
2051 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2053 This option enables configuration of bi_iic_fast[] flags
2054 in u-boot bd_info structure based on u-boot environment
2055 variable "i2cfast". (see also i2cfast)
2057 CONFIG_I2C_MULTI_BUS
2059 This option allows the use of multiple I2C buses, each of which
2060 must have a controller. At any point in time, only one bus is
2061 active. To switch to a different bus, use the 'i2c dev' command.
2062 Note that bus numbering is zero-based.
2064 CONFIG_SYS_I2C_NOPROBES
2066 This option specifies a list of I2C devices that will be skipped
2067 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2068 is set, specify a list of bus-device pairs. Otherwise, specify
2069 a 1D array of device addresses
2072 #undef CONFIG_I2C_MULTI_BUS
2073 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2075 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2077 #define CONFIG_I2C_MULTI_BUS
2078 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2080 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2082 CONFIG_SYS_SPD_BUS_NUM
2084 If defined, then this indicates the I2C bus number for DDR SPD.
2085 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2087 CONFIG_SYS_RTC_BUS_NUM
2089 If defined, then this indicates the I2C bus number for the RTC.
2090 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2092 CONFIG_SYS_DTT_BUS_NUM
2094 If defined, then this indicates the I2C bus number for the DTT.
2095 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2097 CONFIG_SYS_I2C_DTT_ADDR:
2099 If defined, specifies the I2C address of the DTT device.
2100 If not defined, then U-Boot uses predefined value for
2101 specified DTT device.
2105 Define this option if you want to use Freescale's I2C driver in
2106 drivers/i2c/fsl_i2c.c.
2110 Define this option if you have I2C devices reached over 1 .. n
2111 I2C Muxes like the pca9544a. This option addes a new I2C
2112 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2113 new I2C Bus to the existing I2C Busses. If you select the
2114 new Bus with "i2c dev", u-bbot sends first the commandos for
2115 the muxes to activate this new "bus".
2117 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2121 Adding a new I2C Bus reached over 2 pca9544a muxes
2122 The First mux with address 70 and channel 6
2123 The Second mux with address 71 and channel 4
2125 => i2c bus pca9544a:70:6:pca9544a:71:4
2127 Use the "i2c bus" command without parameter, to get a list
2128 of I2C Busses with muxes:
2131 Busses reached over muxes:
2133 reached over Mux(es):
2136 reached over Mux(es):
2141 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2142 u-boot first sends the command to the mux@70 to enable
2143 channel 6, and then the command to the mux@71 to enable
2146 After that, you can use the "normal" i2c commands as
2147 usual to communicate with your I2C devices behind
2150 This option is actually implemented for the bitbanging
2151 algorithm in common/soft_i2c.c and for the Hardware I2C
2152 Bus on the MPC8260. But it should be not so difficult
2153 to add this option to other architectures.
2155 CONFIG_SOFT_I2C_READ_REPEATED_START
2157 defining this will force the i2c_read() function in
2158 the soft_i2c driver to perform an I2C repeated start
2159 between writing the address pointer and reading the
2160 data. If this define is omitted the default behaviour
2161 of doing a stop-start sequence will be used. Most I2C
2162 devices can use either method, but some require one or
2165 - SPI Support: CONFIG_SPI
2167 Enables SPI driver (so far only tested with
2168 SPI EEPROM, also an instance works with Crystal A/D and
2169 D/As on the SACSng board)
2173 Enables the driver for SPI controller on SuperH. Currently
2174 only SH7757 is supported.
2178 Enables extended (16-bit) SPI EEPROM addressing.
2179 (symmetrical to CONFIG_I2C_X)
2183 Enables a software (bit-bang) SPI driver rather than
2184 using hardware support. This is a general purpose
2185 driver that only requires three general I/O port pins
2186 (two outputs, one input) to function. If this is
2187 defined, the board configuration must define several
2188 SPI configuration items (port pins to use, etc). For
2189 an example, see include/configs/sacsng.h.
2193 Enables a hardware SPI driver for general-purpose reads
2194 and writes. As with CONFIG_SOFT_SPI, the board configuration
2195 must define a list of chip-select function pointers.
2196 Currently supported on some MPC8xxx processors. For an
2197 example, see include/configs/mpc8349emds.h.
2201 Enables the driver for the SPI controllers on i.MX and MXC
2202 SoCs. Currently i.MX31/35/51 are supported.
2204 - FPGA Support: CONFIG_FPGA
2206 Enables FPGA subsystem.
2208 CONFIG_FPGA_<vendor>
2210 Enables support for specific chip vendors.
2213 CONFIG_FPGA_<family>
2215 Enables support for FPGA family.
2216 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2220 Specify the number of FPGA devices to support.
2222 CONFIG_SYS_FPGA_PROG_FEEDBACK
2224 Enable printing of hash marks during FPGA configuration.
2226 CONFIG_SYS_FPGA_CHECK_BUSY
2228 Enable checks on FPGA configuration interface busy
2229 status by the configuration function. This option
2230 will require a board or device specific function to
2235 If defined, a function that provides delays in the FPGA
2236 configuration driver.
2238 CONFIG_SYS_FPGA_CHECK_CTRLC
2239 Allow Control-C to interrupt FPGA configuration
2241 CONFIG_SYS_FPGA_CHECK_ERROR
2243 Check for configuration errors during FPGA bitfile
2244 loading. For example, abort during Virtex II
2245 configuration if the INIT_B line goes low (which
2246 indicated a CRC error).
2248 CONFIG_SYS_FPGA_WAIT_INIT
2250 Maximum time to wait for the INIT_B line to deassert
2251 after PROB_B has been deasserted during a Virtex II
2252 FPGA configuration sequence. The default time is 500
2255 CONFIG_SYS_FPGA_WAIT_BUSY
2257 Maximum time to wait for BUSY to deassert during
2258 Virtex II FPGA configuration. The default is 5 ms.
2260 CONFIG_SYS_FPGA_WAIT_CONFIG
2262 Time to wait after FPGA configuration. The default is
2265 - Configuration Management:
2268 If defined, this string will be added to the U-Boot
2269 version information (U_BOOT_VERSION)
2271 - Vendor Parameter Protection:
2273 U-Boot considers the values of the environment
2274 variables "serial#" (Board Serial Number) and
2275 "ethaddr" (Ethernet Address) to be parameters that
2276 are set once by the board vendor / manufacturer, and
2277 protects these variables from casual modification by
2278 the user. Once set, these variables are read-only,
2279 and write or delete attempts are rejected. You can
2280 change this behaviour:
2282 If CONFIG_ENV_OVERWRITE is #defined in your config
2283 file, the write protection for vendor parameters is
2284 completely disabled. Anybody can change or delete
2287 Alternatively, if you #define _both_ CONFIG_ETHADDR
2288 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2289 Ethernet address is installed in the environment,
2290 which can be changed exactly ONCE by the user. [The
2291 serial# is unaffected by this, i. e. it remains
2294 The same can be accomplished in a more flexible way
2295 for any variable by configuring the type of access
2296 to allow for those variables in the ".flags" variable
2297 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2302 Define this variable to enable the reservation of
2303 "protected RAM", i. e. RAM which is not overwritten
2304 by U-Boot. Define CONFIG_PRAM to hold the number of
2305 kB you want to reserve for pRAM. You can overwrite
2306 this default value by defining an environment
2307 variable "pram" to the number of kB you want to
2308 reserve. Note that the board info structure will
2309 still show the full amount of RAM. If pRAM is
2310 reserved, a new environment variable "mem" will
2311 automatically be defined to hold the amount of
2312 remaining RAM in a form that can be passed as boot
2313 argument to Linux, for instance like that:
2315 setenv bootargs ... mem=\${mem}
2318 This way you can tell Linux not to use this memory,
2319 either, which results in a memory region that will
2320 not be affected by reboots.
2322 *WARNING* If your board configuration uses automatic
2323 detection of the RAM size, you must make sure that
2324 this memory test is non-destructive. So far, the
2325 following board configurations are known to be
2328 IVMS8, IVML24, SPD8xx, TQM8xxL,
2329 HERMES, IP860, RPXlite, LWMON,
2332 - Access to physical memory region (> 4GB)
2333 Some basic support is provided for operations on memory not
2334 normally accessible to U-Boot - e.g. some architectures
2335 support access to more than 4GB of memory on 32-bit
2336 machines using physical address extension or similar.
2337 Define CONFIG_PHYSMEM to access this basic support, which
2338 currently only supports clearing the memory.
2343 Define this variable to stop the system in case of a
2344 fatal error, so that you have to reset it manually.
2345 This is probably NOT a good idea for an embedded
2346 system where you want the system to reboot
2347 automatically as fast as possible, but it may be
2348 useful during development since you can try to debug
2349 the conditions that lead to the situation.
2351 CONFIG_NET_RETRY_COUNT
2353 This variable defines the number of retries for
2354 network operations like ARP, RARP, TFTP, or BOOTP
2355 before giving up the operation. If not defined, a
2356 default value of 5 is used.
2360 Timeout waiting for an ARP reply in milliseconds.
2364 Timeout in milliseconds used in NFS protocol.
2365 If you encounter "ERROR: Cannot umount" in nfs command,
2366 try longer timeout such as
2367 #define CONFIG_NFS_TIMEOUT 10000UL
2369 - Command Interpreter:
2370 CONFIG_AUTO_COMPLETE
2372 Enable auto completion of commands using TAB.
2374 Note that this feature has NOT been implemented yet
2375 for the "hush" shell.
2378 CONFIG_SYS_HUSH_PARSER
2380 Define this variable to enable the "hush" shell (from
2381 Busybox) as command line interpreter, thus enabling
2382 powerful command line syntax like
2383 if...then...else...fi conditionals or `&&' and '||'
2384 constructs ("shell scripts").
2386 If undefined, you get the old, much simpler behaviour
2387 with a somewhat smaller memory footprint.
2390 CONFIG_SYS_PROMPT_HUSH_PS2
2392 This defines the secondary prompt string, which is
2393 printed when the command interpreter needs more input
2394 to complete a command. Usually "> ".
2398 In the current implementation, the local variables
2399 space and global environment variables space are
2400 separated. Local variables are those you define by
2401 simply typing `name=value'. To access a local
2402 variable later on, you have write `$name' or
2403 `${name}'; to execute the contents of a variable
2404 directly type `$name' at the command prompt.
2406 Global environment variables are those you use
2407 setenv/printenv to work with. To run a command stored
2408 in such a variable, you need to use the run command,
2409 and you must not use the '$' sign to access them.
2411 To store commands and special characters in a
2412 variable, please use double quotation marks
2413 surrounding the whole text of the variable, instead
2414 of the backslashes before semicolons and special
2417 - Commandline Editing and History:
2418 CONFIG_CMDLINE_EDITING
2420 Enable editing and History functions for interactive
2421 commandline input operations
2423 - Default Environment:
2424 CONFIG_EXTRA_ENV_SETTINGS
2426 Define this to contain any number of null terminated
2427 strings (variable = value pairs) that will be part of
2428 the default environment compiled into the boot image.
2430 For example, place something like this in your
2431 board's config file:
2433 #define CONFIG_EXTRA_ENV_SETTINGS \
2437 Warning: This method is based on knowledge about the
2438 internal format how the environment is stored by the
2439 U-Boot code. This is NOT an official, exported
2440 interface! Although it is unlikely that this format
2441 will change soon, there is no guarantee either.
2442 You better know what you are doing here.
2444 Note: overly (ab)use of the default environment is
2445 discouraged. Make sure to check other ways to preset
2446 the environment like the "source" command or the
2449 CONFIG_ENV_VARS_UBOOT_CONFIG
2451 Define this in order to add variables describing the
2452 U-Boot build configuration to the default environment.
2453 These will be named arch, cpu, board, vendor, and soc.
2455 Enabling this option will cause the following to be defined:
2463 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2465 Define this in order to add variables describing certain
2466 run-time determined information about the hardware to the
2467 environment. These will be named board_name, board_rev.
2469 CONFIG_DELAY_ENVIRONMENT
2471 Normally the environment is loaded when the board is
2472 intialised so that it is available to U-Boot. This inhibits
2473 that so that the environment is not available until
2474 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2475 this is instead controlled by the value of
2476 /config/load-environment.
2478 - DataFlash Support:
2479 CONFIG_HAS_DATAFLASH
2481 Defining this option enables DataFlash features and
2482 allows to read/write in Dataflash via the standard
2485 - Serial Flash support
2488 Defining this option enables SPI flash commands
2489 'sf probe/read/write/erase/update'.
2491 Usage requires an initial 'probe' to define the serial
2492 flash parameters, followed by read/write/erase/update
2495 The following defaults may be provided by the platform
2496 to handle the common case when only a single serial
2497 flash is present on the system.
2499 CONFIG_SF_DEFAULT_BUS Bus identifier
2500 CONFIG_SF_DEFAULT_CS Chip-select
2501 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2502 CONFIG_SF_DEFAULT_SPEED in Hz
2506 Define this option to include a destructive SPI flash
2509 - SystemACE Support:
2512 Adding this option adds support for Xilinx SystemACE
2513 chips attached via some sort of local bus. The address
2514 of the chip must also be defined in the
2515 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2517 #define CONFIG_SYSTEMACE
2518 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2520 When SystemACE support is added, the "ace" device type
2521 becomes available to the fat commands, i.e. fatls.
2523 - TFTP Fixed UDP Port:
2526 If this is defined, the environment variable tftpsrcp
2527 is used to supply the TFTP UDP source port value.
2528 If tftpsrcp isn't defined, the normal pseudo-random port
2529 number generator is used.
2531 Also, the environment variable tftpdstp is used to supply
2532 the TFTP UDP destination port value. If tftpdstp isn't
2533 defined, the normal port 69 is used.
2535 The purpose for tftpsrcp is to allow a TFTP server to
2536 blindly start the TFTP transfer using the pre-configured
2537 target IP address and UDP port. This has the effect of
2538 "punching through" the (Windows XP) firewall, allowing
2539 the remainder of the TFTP transfer to proceed normally.
2540 A better solution is to properly configure the firewall,
2541 but sometimes that is not allowed.
2546 This enables a generic 'hash' command which can produce
2547 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2551 Enable the hash verify command (hash -v). This adds to code
2554 CONFIG_SHA1 - support SHA1 hashing
2555 CONFIG_SHA256 - support SHA256 hashing
2557 Note: There is also a sha1sum command, which should perhaps
2558 be deprecated in favour of 'hash sha1'.
2560 - Show boot progress:
2561 CONFIG_SHOW_BOOT_PROGRESS
2563 Defining this option allows to add some board-
2564 specific code (calling a user-provided function
2565 "show_boot_progress(int)") that enables you to show
2566 the system's boot progress on some display (for
2567 example, some LED's) on your board. At the moment,
2568 the following checkpoints are implemented:
2570 - Detailed boot stage timing
2572 Define this option to get detailed timing of each stage
2573 of the boot process.
2575 CONFIG_BOOTSTAGE_USER_COUNT
2576 This is the number of available user bootstage records.
2577 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2578 a new ID will be allocated from this stash. If you exceed
2579 the limit, recording will stop.
2581 CONFIG_BOOTSTAGE_REPORT
2582 Define this to print a report before boot, similar to this:
2584 Timer summary in microseconds:
2587 3,575,678 3,575,678 board_init_f start
2588 3,575,695 17 arch_cpu_init A9
2589 3,575,777 82 arch_cpu_init done
2590 3,659,598 83,821 board_init_r start
2591 3,910,375 250,777 main_loop
2592 29,916,167 26,005,792 bootm_start
2593 30,361,327 445,160 start_kernel
2595 CONFIG_CMD_BOOTSTAGE
2596 Add a 'bootstage' command which supports printing a report
2597 and un/stashing of bootstage data.
2599 CONFIG_BOOTSTAGE_FDT
2600 Stash the bootstage information in the FDT. A root 'bootstage'
2601 node is created with each bootstage id as a child. Each child
2602 has a 'name' property and either 'mark' containing the
2603 mark time in microsecond, or 'accum' containing the
2604 accumulated time for that bootstage id in microseconds.
2609 name = "board_init_f";
2618 Code in the Linux kernel can find this in /proc/devicetree.
2620 Legacy uImage format:
2623 1 common/cmd_bootm.c before attempting to boot an image
2624 -1 common/cmd_bootm.c Image header has bad magic number
2625 2 common/cmd_bootm.c Image header has correct magic number
2626 -2 common/cmd_bootm.c Image header has bad checksum
2627 3 common/cmd_bootm.c Image header has correct checksum
2628 -3 common/cmd_bootm.c Image data has bad checksum
2629 4 common/cmd_bootm.c Image data has correct checksum
2630 -4 common/cmd_bootm.c Image is for unsupported architecture
2631 5 common/cmd_bootm.c Architecture check OK
2632 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2633 6 common/cmd_bootm.c Image Type check OK
2634 -6 common/cmd_bootm.c gunzip uncompression error
2635 -7 common/cmd_bootm.c Unimplemented compression type
2636 7 common/cmd_bootm.c Uncompression OK
2637 8 common/cmd_bootm.c No uncompress/copy overwrite error
2638 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2640 9 common/image.c Start initial ramdisk verification
2641 -10 common/image.c Ramdisk header has bad magic number
2642 -11 common/image.c Ramdisk header has bad checksum
2643 10 common/image.c Ramdisk header is OK
2644 -12 common/image.c Ramdisk data has bad checksum
2645 11 common/image.c Ramdisk data has correct checksum
2646 12 common/image.c Ramdisk verification complete, start loading
2647 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2648 13 common/image.c Start multifile image verification
2649 14 common/image.c No initial ramdisk, no multifile, continue.
2651 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2653 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2654 -31 post/post.c POST test failed, detected by post_output_backlog()
2655 -32 post/post.c POST test failed, detected by post_run_single()
2657 34 common/cmd_doc.c before loading a Image from a DOC device
2658 -35 common/cmd_doc.c Bad usage of "doc" command
2659 35 common/cmd_doc.c correct usage of "doc" command
2660 -36 common/cmd_doc.c No boot device
2661 36 common/cmd_doc.c correct boot device
2662 -37 common/cmd_doc.c Unknown Chip ID on boot device
2663 37 common/cmd_doc.c correct chip ID found, device available
2664 -38 common/cmd_doc.c Read Error on boot device
2665 38 common/cmd_doc.c reading Image header from DOC device OK
2666 -39 common/cmd_doc.c Image header has bad magic number
2667 39 common/cmd_doc.c Image header has correct magic number
2668 -40 common/cmd_doc.c Error reading Image from DOC device
2669 40 common/cmd_doc.c Image header has correct magic number
2670 41 common/cmd_ide.c before loading a Image from a IDE device
2671 -42 common/cmd_ide.c Bad usage of "ide" command
2672 42 common/cmd_ide.c correct usage of "ide" command
2673 -43 common/cmd_ide.c No boot device
2674 43 common/cmd_ide.c boot device found
2675 -44 common/cmd_ide.c Device not available
2676 44 common/cmd_ide.c Device available
2677 -45 common/cmd_ide.c wrong partition selected
2678 45 common/cmd_ide.c partition selected
2679 -46 common/cmd_ide.c Unknown partition table
2680 46 common/cmd_ide.c valid partition table found
2681 -47 common/cmd_ide.c Invalid partition type
2682 47 common/cmd_ide.c correct partition type
2683 -48 common/cmd_ide.c Error reading Image Header on boot device
2684 48 common/cmd_ide.c reading Image Header from IDE device OK
2685 -49 common/cmd_ide.c Image header has bad magic number
2686 49 common/cmd_ide.c Image header has correct magic number
2687 -50 common/cmd_ide.c Image header has bad checksum
2688 50 common/cmd_ide.c Image header has correct checksum
2689 -51 common/cmd_ide.c Error reading Image from IDE device
2690 51 common/cmd_ide.c reading Image from IDE device OK
2691 52 common/cmd_nand.c before loading a Image from a NAND device
2692 -53 common/cmd_nand.c Bad usage of "nand" command
2693 53 common/cmd_nand.c correct usage of "nand" command
2694 -54 common/cmd_nand.c No boot device
2695 54 common/cmd_nand.c boot device found
2696 -55 common/cmd_nand.c Unknown Chip ID on boot device
2697 55 common/cmd_nand.c correct chip ID found, device available
2698 -56 common/cmd_nand.c Error reading Image Header on boot device
2699 56 common/cmd_nand.c reading Image Header from NAND device OK
2700 -57 common/cmd_nand.c Image header has bad magic number
2701 57 common/cmd_nand.c Image header has correct magic number
2702 -58 common/cmd_nand.c Error reading Image from NAND device
2703 58 common/cmd_nand.c reading Image from NAND device OK
2705 -60 common/env_common.c Environment has a bad CRC, using default
2707 64 net/eth.c starting with Ethernet configuration.
2708 -64 net/eth.c no Ethernet found.
2709 65 net/eth.c Ethernet found.
2711 -80 common/cmd_net.c usage wrong
2712 80 common/cmd_net.c before calling NetLoop()
2713 -81 common/cmd_net.c some error in NetLoop() occurred
2714 81 common/cmd_net.c NetLoop() back without error
2715 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2716 82 common/cmd_net.c trying automatic boot
2717 83 common/cmd_net.c running "source" command
2718 -83 common/cmd_net.c some error in automatic boot or "source" command
2719 84 common/cmd_net.c end without errors
2724 100 common/cmd_bootm.c Kernel FIT Image has correct format
2725 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2726 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2727 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2728 102 common/cmd_bootm.c Kernel unit name specified
2729 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2730 103 common/cmd_bootm.c Found configuration node
2731 104 common/cmd_bootm.c Got kernel subimage node offset
2732 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2733 105 common/cmd_bootm.c Kernel subimage hash verification OK
2734 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2735 106 common/cmd_bootm.c Architecture check OK
2736 -106 common/cmd_bootm.c Kernel subimage has wrong type
2737 107 common/cmd_bootm.c Kernel subimage type OK
2738 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2739 108 common/cmd_bootm.c Got kernel subimage data/size
2740 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2741 -109 common/cmd_bootm.c Can't get kernel subimage type
2742 -110 common/cmd_bootm.c Can't get kernel subimage comp
2743 -111 common/cmd_bootm.c Can't get kernel subimage os
2744 -112 common/cmd_bootm.c Can't get kernel subimage load address
2745 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2747 120 common/image.c Start initial ramdisk verification
2748 -120 common/image.c Ramdisk FIT image has incorrect format
2749 121 common/image.c Ramdisk FIT image has correct format
2750 122 common/image.c No ramdisk subimage unit name, using configuration
2751 -122 common/image.c Can't get configuration for ramdisk subimage
2752 123 common/image.c Ramdisk unit name specified
2753 -124 common/image.c Can't get ramdisk subimage node offset
2754 125 common/image.c Got ramdisk subimage node offset
2755 -125 common/image.c Ramdisk subimage hash verification failed
2756 126 common/image.c Ramdisk subimage hash verification OK
2757 -126 common/image.c Ramdisk subimage for unsupported architecture
2758 127 common/image.c Architecture check OK
2759 -127 common/image.c Can't get ramdisk subimage data/size
2760 128 common/image.c Got ramdisk subimage data/size
2761 129 common/image.c Can't get ramdisk load address
2762 -129 common/image.c Got ramdisk load address
2764 -130 common/cmd_doc.c Incorrect FIT image format
2765 131 common/cmd_doc.c FIT image format OK
2767 -140 common/cmd_ide.c Incorrect FIT image format
2768 141 common/cmd_ide.c FIT image format OK
2770 -150 common/cmd_nand.c Incorrect FIT image format
2771 151 common/cmd_nand.c FIT image format OK
2773 - FIT image support:
2775 Enable support for the FIT uImage format.
2777 CONFIG_FIT_BEST_MATCH
2778 When no configuration is explicitly selected, default to the
2779 one whose fdt's compatibility field best matches that of
2780 U-Boot itself. A match is considered "best" if it matches the
2781 most specific compatibility entry of U-Boot's fdt's root node.
2782 The order of entries in the configuration's fdt is ignored.
2784 - Standalone program support:
2785 CONFIG_STANDALONE_LOAD_ADDR
2787 This option defines a board specific value for the
2788 address where standalone program gets loaded, thus
2789 overwriting the architecture dependent default
2792 - Frame Buffer Address:
2795 Define CONFIG_FB_ADDR if you want to use specific
2796 address for frame buffer. This is typically the case
2797 when using a graphics controller has separate video
2798 memory. U-Boot will then place the frame buffer at
2799 the given address instead of dynamically reserving it
2800 in system RAM by calling lcd_setmem(), which grabs
2801 the memory for the frame buffer depending on the
2802 configured panel size.
2804 Please see board_init_f function.
2806 - Automatic software updates via TFTP server
2808 CONFIG_UPDATE_TFTP_CNT_MAX
2809 CONFIG_UPDATE_TFTP_MSEC_MAX
2811 These options enable and control the auto-update feature;
2812 for a more detailed description refer to doc/README.update.
2814 - MTD Support (mtdparts command, UBI support)
2817 Adds the MTD device infrastructure from the Linux kernel.
2818 Needed for mtdparts command support.
2820 CONFIG_MTD_PARTITIONS
2822 Adds the MTD partitioning infrastructure from the Linux
2823 kernel. Needed for UBI support.
2828 Adds commands for interacting with MTD partitions formatted
2829 with the UBI flash translation layer
2831 Requires also defining CONFIG_RBTREE
2833 CONFIG_UBI_SILENCE_MSG
2835 Make the verbose messages from UBI stop printing. This leaves
2836 warnings and errors enabled.
2841 Adds commands for interacting with UBI volumes formatted as
2842 UBIFS. UBIFS is read-only in u-boot.
2844 Requires UBI support as well as CONFIG_LZO
2846 CONFIG_UBIFS_SILENCE_MSG
2848 Make the verbose messages from UBIFS stop printing. This leaves
2849 warnings and errors enabled.
2853 Enable building of SPL globally.
2856 LDSCRIPT for linking the SPL binary.
2858 CONFIG_SPL_MAX_FOOTPRINT
2859 Maximum size in memory allocated to the SPL, BSS included.
2860 When defined, the linker checks that the actual memory
2861 used by SPL from _start to __bss_end does not exceed it.
2862 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2863 must not be both defined at the same time.
2866 Maximum size of the SPL image (text, data, rodata, and
2867 linker lists sections), BSS excluded.
2868 When defined, the linker checks that the actual size does
2871 CONFIG_SPL_TEXT_BASE
2872 TEXT_BASE for linking the SPL binary.
2874 CONFIG_SPL_RELOC_TEXT_BASE
2875 Address to relocate to. If unspecified, this is equal to
2876 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2878 CONFIG_SPL_BSS_START_ADDR
2879 Link address for the BSS within the SPL binary.
2881 CONFIG_SPL_BSS_MAX_SIZE
2882 Maximum size in memory allocated to the SPL BSS.
2883 When defined, the linker checks that the actual memory used
2884 by SPL from __bss_start to __bss_end does not exceed it.
2885 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2886 must not be both defined at the same time.
2889 Adress of the start of the stack SPL will use
2891 CONFIG_SPL_RELOC_STACK
2892 Adress of the start of the stack SPL will use after
2893 relocation. If unspecified, this is equal to
2896 CONFIG_SYS_SPL_MALLOC_START
2897 Starting address of the malloc pool used in SPL.
2899 CONFIG_SYS_SPL_MALLOC_SIZE
2900 The size of the malloc pool used in SPL.
2902 CONFIG_SPL_FRAMEWORK
2903 Enable the SPL framework under common/. This framework
2904 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2905 NAND loading of the Linux Kernel.
2907 CONFIG_SPL_DISPLAY_PRINT
2908 For ARM, enable an optional function to print more information
2909 about the running system.
2911 CONFIG_SPL_INIT_MINIMAL
2912 Arch init code should be built for a very small image
2914 CONFIG_SPL_LIBCOMMON_SUPPORT
2915 Support for common/libcommon.o in SPL binary
2917 CONFIG_SPL_LIBDISK_SUPPORT
2918 Support for disk/libdisk.o in SPL binary
2920 CONFIG_SPL_I2C_SUPPORT
2921 Support for drivers/i2c/libi2c.o in SPL binary
2923 CONFIG_SPL_GPIO_SUPPORT
2924 Support for drivers/gpio/libgpio.o in SPL binary
2926 CONFIG_SPL_MMC_SUPPORT
2927 Support for drivers/mmc/libmmc.o in SPL binary
2929 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2930 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2931 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2932 Address, size and partition on the MMC to load U-Boot from
2933 when the MMC is being used in raw mode.
2935 CONFIG_SPL_FAT_SUPPORT
2936 Support for fs/fat/libfat.o in SPL binary
2938 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2939 Filename to read to load U-Boot when reading from FAT
2941 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2942 Set this for NAND SPL on PPC mpc83xx targets, so that
2943 start.S waits for the rest of the SPL to load before
2944 continuing (the hardware starts execution after just
2945 loading the first page rather than the full 4K).
2947 CONFIG_SPL_NAND_BASE
2948 Include nand_base.c in the SPL. Requires
2949 CONFIG_SPL_NAND_DRIVERS.
2951 CONFIG_SPL_NAND_DRIVERS
2952 SPL uses normal NAND drivers, not minimal drivers.
2955 Include standard software ECC in the SPL
2957 CONFIG_SPL_NAND_SIMPLE
2958 Support for NAND boot using simple NAND drivers that
2959 expose the cmd_ctrl() interface.
2961 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2962 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2963 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2964 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2965 CONFIG_SYS_NAND_ECCBYTES
2966 Defines the size and behavior of the NAND that SPL uses
2969 CONFIG_SYS_NAND_U_BOOT_OFFS
2970 Location in NAND to read U-Boot from
2972 CONFIG_SYS_NAND_U_BOOT_DST
2973 Location in memory to load U-Boot to
2975 CONFIG_SYS_NAND_U_BOOT_SIZE
2976 Size of image to load
2978 CONFIG_SYS_NAND_U_BOOT_START
2979 Entry point in loaded image to jump to
2981 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2982 Define this if you need to first read the OOB and then the
2983 data. This is used for example on davinci plattforms.
2985 CONFIG_SPL_OMAP3_ID_NAND
2986 Support for an OMAP3-specific set of functions to return the
2987 ID and MFR of the first attached NAND chip, if present.
2989 CONFIG_SPL_SERIAL_SUPPORT
2990 Support for drivers/serial/libserial.o in SPL binary
2992 CONFIG_SPL_SPI_FLASH_SUPPORT
2993 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2995 CONFIG_SPL_SPI_SUPPORT
2996 Support for drivers/spi/libspi.o in SPL binary
2998 CONFIG_SPL_RAM_DEVICE
2999 Support for running image already present in ram, in SPL binary
3001 CONFIG_SPL_LIBGENERIC_SUPPORT
3002 Support for lib/libgeneric.o in SPL binary
3005 Image offset to which the SPL should be padded before appending
3006 the SPL payload. By default, this is defined as
3007 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3008 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3009 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3012 Final target image containing SPL and payload. Some SPLs
3013 use an arch-specific makefile fragment instead, for
3014 example if more than one image needs to be produced.
3016 CONFIG_FIT_SPL_PRINT
3017 Printing information about a FIT image adds quite a bit of
3018 code to SPL. So this is normally disabled in SPL. Use this
3019 option to re-enable it. This will affect the output of the
3020 bootm command when booting a FIT image.
3025 [so far only for SMDK2400 boards]
3027 - Modem support enable:
3028 CONFIG_MODEM_SUPPORT
3030 - RTS/CTS Flow control enable:
3033 - Modem debug support:
3034 CONFIG_MODEM_SUPPORT_DEBUG
3036 Enables debugging stuff (char screen[1024], dbg())
3037 for modem support. Useful only with BDI2000.
3039 - Interrupt support (PPC):
3041 There are common interrupt_init() and timer_interrupt()
3042 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3043 for CPU specific initialization. interrupt_init_cpu()
3044 should set decrementer_count to appropriate value. If
3045 CPU resets decrementer automatically after interrupt
3046 (ppc4xx) it should set decrementer_count to zero.
3047 timer_interrupt() calls timer_interrupt_cpu() for CPU
3048 specific handling. If board has watchdog / status_led
3049 / other_activity_monitor it works automatically from
3050 general timer_interrupt().
3054 In the target system modem support is enabled when a
3055 specific key (key combination) is pressed during
3056 power-on. Otherwise U-Boot will boot normally
3057 (autoboot). The key_pressed() function is called from
3058 board_init(). Currently key_pressed() is a dummy
3059 function, returning 1 and thus enabling modem
3062 If there are no modem init strings in the
3063 environment, U-Boot proceed to autoboot; the
3064 previous output (banner, info printfs) will be
3067 See also: doc/README.Modem
3069 Board initialization settings:
3070 ------------------------------
3072 During Initialization u-boot calls a number of board specific functions
3073 to allow the preparation of board specific prerequisites, e.g. pin setup
3074 before drivers are initialized. To enable these callbacks the
3075 following configuration macros have to be defined. Currently this is
3076 architecture specific, so please check arch/your_architecture/lib/board.c
3077 typically in board_init_f() and board_init_r().
3079 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3080 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3081 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3082 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3084 Configuration Settings:
3085 -----------------------
3087 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3088 undefine this when you're short of memory.
3090 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3091 width of the commands listed in the 'help' command output.
3093 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3094 prompt for user input.
3096 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3098 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3100 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3102 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3103 the application (usually a Linux kernel) when it is
3106 - CONFIG_SYS_BAUDRATE_TABLE:
3107 List of legal baudrate settings for this board.
3109 - CONFIG_SYS_CONSOLE_INFO_QUIET
3110 Suppress display of console information at boot.
3112 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3113 If the board specific function
3114 extern int overwrite_console (void);
3115 returns 1, the stdin, stderr and stdout are switched to the
3116 serial port, else the settings in the environment are used.
3118 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3119 Enable the call to overwrite_console().
3121 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3122 Enable overwrite of previous console environment settings.
3124 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3125 Begin and End addresses of the area used by the
3128 - CONFIG_SYS_ALT_MEMTEST:
3129 Enable an alternate, more extensive memory test.
3131 - CONFIG_SYS_MEMTEST_SCRATCH:
3132 Scratch address used by the alternate memory test
3133 You only need to set this if address zero isn't writeable
3135 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3136 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3137 this specified memory area will get subtracted from the top
3138 (end) of RAM and won't get "touched" at all by U-Boot. By
3139 fixing up gd->ram_size the Linux kernel should gets passed
3140 the now "corrected" memory size and won't touch it either.
3141 This should work for arch/ppc and arch/powerpc. Only Linux
3142 board ports in arch/powerpc with bootwrapper support that
3143 recalculate the memory size from the SDRAM controller setup
3144 will have to get fixed in Linux additionally.
3146 This option can be used as a workaround for the 440EPx/GRx
3147 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3150 WARNING: Please make sure that this value is a multiple of
3151 the Linux page size (normally 4k). If this is not the case,
3152 then the end address of the Linux memory will be located at a
3153 non page size aligned address and this could cause major
3156 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3157 Enable temporary baudrate change while serial download
3159 - CONFIG_SYS_SDRAM_BASE:
3160 Physical start address of SDRAM. _Must_ be 0 here.
3162 - CONFIG_SYS_MBIO_BASE:
3163 Physical start address of Motherboard I/O (if using a
3166 - CONFIG_SYS_FLASH_BASE:
3167 Physical start address of Flash memory.
3169 - CONFIG_SYS_MONITOR_BASE:
3170 Physical start address of boot monitor code (set by
3171 make config files to be same as the text base address
3172 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3173 CONFIG_SYS_FLASH_BASE when booting from flash.
3175 - CONFIG_SYS_MONITOR_LEN:
3176 Size of memory reserved for monitor code, used to
3177 determine _at_compile_time_ (!) if the environment is
3178 embedded within the U-Boot image, or in a separate
3181 - CONFIG_SYS_MALLOC_LEN:
3182 Size of DRAM reserved for malloc() use.
3184 - CONFIG_SYS_BOOTM_LEN:
3185 Normally compressed uImages are limited to an
3186 uncompressed size of 8 MBytes. If this is not enough,
3187 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3188 to adjust this setting to your needs.
3190 - CONFIG_SYS_BOOTMAPSZ:
3191 Maximum size of memory mapped by the startup code of
3192 the Linux kernel; all data that must be processed by
3193 the Linux kernel (bd_info, boot arguments, FDT blob if
3194 used) must be put below this limit, unless "bootm_low"
3195 enviroment variable is defined and non-zero. In such case
3196 all data for the Linux kernel must be between "bootm_low"
3197 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3198 variable "bootm_mapsize" will override the value of
3199 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3200 then the value in "bootm_size" will be used instead.
3202 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3203 Enable initrd_high functionality. If defined then the
3204 initrd_high feature is enabled and the bootm ramdisk subcommand
3207 - CONFIG_SYS_BOOT_GET_CMDLINE:
3208 Enables allocating and saving kernel cmdline in space between
3209 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3211 - CONFIG_SYS_BOOT_GET_KBD:
3212 Enables allocating and saving a kernel copy of the bd_info in
3213 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3215 - CONFIG_SYS_MAX_FLASH_BANKS:
3216 Max number of Flash memory banks
3218 - CONFIG_SYS_MAX_FLASH_SECT:
3219 Max number of sectors on a Flash chip
3221 - CONFIG_SYS_FLASH_ERASE_TOUT:
3222 Timeout for Flash erase operations (in ms)
3224 - CONFIG_SYS_FLASH_WRITE_TOUT:
3225 Timeout for Flash write operations (in ms)
3227 - CONFIG_SYS_FLASH_LOCK_TOUT
3228 Timeout for Flash set sector lock bit operation (in ms)
3230 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3231 Timeout for Flash clear lock bits operation (in ms)
3233 - CONFIG_SYS_FLASH_PROTECTION
3234 If defined, hardware flash sectors protection is used
3235 instead of U-Boot software protection.
3237 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3239 Enable TFTP transfers directly to flash memory;
3240 without this option such a download has to be
3241 performed in two steps: (1) download to RAM, and (2)
3242 copy from RAM to flash.
3244 The two-step approach is usually more reliable, since
3245 you can check if the download worked before you erase
3246 the flash, but in some situations (when system RAM is
3247 too limited to allow for a temporary copy of the
3248 downloaded image) this option may be very useful.
3250 - CONFIG_SYS_FLASH_CFI:
3251 Define if the flash driver uses extra elements in the
3252 common flash structure for storing flash geometry.
3254 - CONFIG_FLASH_CFI_DRIVER
3255 This option also enables the building of the cfi_flash driver
3256 in the drivers directory
3258 - CONFIG_FLASH_CFI_MTD
3259 This option enables the building of the cfi_mtd driver
3260 in the drivers directory. The driver exports CFI flash
3263 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3264 Use buffered writes to flash.
3266 - CONFIG_FLASH_SPANSION_S29WS_N
3267 s29ws-n MirrorBit flash has non-standard addresses for buffered
3270 - CONFIG_SYS_FLASH_QUIET_TEST
3271 If this option is defined, the common CFI flash doesn't
3272 print it's warning upon not recognized FLASH banks. This
3273 is useful, if some of the configured banks are only
3274 optionally available.
3276 - CONFIG_FLASH_SHOW_PROGRESS
3277 If defined (must be an integer), print out countdown
3278 digits and dots. Recommended value: 45 (9..1) for 80
3279 column displays, 15 (3..1) for 40 column displays.
3281 - CONFIG_FLASH_VERIFY
3282 If defined, the content of the flash (destination) is compared
3283 against the source after the write operation. An error message
3284 will be printed when the contents are not identical.
3285 Please note that this option is useless in nearly all cases,
3286 since such flash programming errors usually are detected earlier
3287 while unprotecting/erasing/programming. Please only enable
3288 this option if you really know what you are doing.
3290 - CONFIG_SYS_RX_ETH_BUFFER:
3291 Defines the number of Ethernet receive buffers. On some
3292 Ethernet controllers it is recommended to set this value
3293 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3294 buffers can be full shortly after enabling the interface
3295 on high Ethernet traffic.
3296 Defaults to 4 if not defined.
3298 - CONFIG_ENV_MAX_ENTRIES
3300 Maximum number of entries in the hash table that is used
3301 internally to store the environment settings. The default
3302 setting is supposed to be generous and should work in most
3303 cases. This setting can be used to tune behaviour; see
3304 lib/hashtable.c for details.
3306 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3307 - CONFIG_ENV_FLAGS_LIST_STATIC
3308 Enable validation of the values given to enviroment variables when
3309 calling env set. Variables can be restricted to only decimal,
3310 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3311 the variables can also be restricted to IP address or MAC address.
3313 The format of the list is:
3314 type_attribute = [s|d|x|b|i|m]
3315 access_atribute = [a|r|o|c]
3316 attributes = type_attribute[access_atribute]
3317 entry = variable_name[:attributes]
3320 The type attributes are:
3321 s - String (default)
3324 b - Boolean ([1yYtT|0nNfF])
3328 The access attributes are:
3334 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3335 Define this to a list (string) to define the ".flags"
3336 envirnoment variable in the default or embedded environment.
3338 - CONFIG_ENV_FLAGS_LIST_STATIC
3339 Define this to a list (string) to define validation that
3340 should be done if an entry is not found in the ".flags"
3341 environment variable. To override a setting in the static
3342 list, simply add an entry for the same variable name to the
3345 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3346 If defined, don't allow the -f switch to env set override variable
3349 - CONFIG_SYS_GENERIC_BOARD
3350 This selects the architecture-generic board system instead of the
3351 architecture-specific board files. It is intended to move boards
3352 to this new framework over time. Defining this will disable the
3353 arch/foo/lib/board.c file and use common/board_f.c and
3354 common/board_r.c instead. To use this option your architecture
3355 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3356 its config.mk file). If you find problems enabling this option on
3357 your board please report the problem and send patches!
3359 - CONFIG_SYS_SYM_OFFSETS
3360 This is set by architectures that use offsets for link symbols
3361 instead of absolute values. So bss_start is obtained using an
3362 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3363 directly. You should not need to touch this setting.
3365 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3366 This is set by OMAP boards for the max time that reset should
3367 be asserted. See doc/README.omap-reset-time for details on how
3368 the value can be calulated on a given board.
3370 The following definitions that deal with the placement and management
3371 of environment data (variable area); in general, we support the
3372 following configurations:
3374 - CONFIG_BUILD_ENVCRC:
3376 Builds up envcrc with the target environment so that external utils
3377 may easily extract it and embed it in final U-Boot images.
3379 - CONFIG_ENV_IS_IN_FLASH:
3381 Define this if the environment is in flash memory.
3383 a) The environment occupies one whole flash sector, which is
3384 "embedded" in the text segment with the U-Boot code. This
3385 happens usually with "bottom boot sector" or "top boot
3386 sector" type flash chips, which have several smaller
3387 sectors at the start or the end. For instance, such a
3388 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3389 such a case you would place the environment in one of the
3390 4 kB sectors - with U-Boot code before and after it. With
3391 "top boot sector" type flash chips, you would put the
3392 environment in one of the last sectors, leaving a gap
3393 between U-Boot and the environment.
3395 - CONFIG_ENV_OFFSET:
3397 Offset of environment data (variable area) to the
3398 beginning of flash memory; for instance, with bottom boot
3399 type flash chips the second sector can be used: the offset
3400 for this sector is given here.
3402 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3406 This is just another way to specify the start address of
3407 the flash sector containing the environment (instead of
3410 - CONFIG_ENV_SECT_SIZE:
3412 Size of the sector containing the environment.
3415 b) Sometimes flash chips have few, equal sized, BIG sectors.
3416 In such a case you don't want to spend a whole sector for
3421 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3422 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3423 of this flash sector for the environment. This saves
3424 memory for the RAM copy of the environment.
3426 It may also save flash memory if you decide to use this
3427 when your environment is "embedded" within U-Boot code,
3428 since then the remainder of the flash sector could be used
3429 for U-Boot code. It should be pointed out that this is
3430 STRONGLY DISCOURAGED from a robustness point of view:
3431 updating the environment in flash makes it always
3432 necessary to erase the WHOLE sector. If something goes
3433 wrong before the contents has been restored from a copy in
3434 RAM, your target system will be dead.
3436 - CONFIG_ENV_ADDR_REDUND
3437 CONFIG_ENV_SIZE_REDUND
3439 These settings describe a second storage area used to hold
3440 a redundant copy of the environment data, so that there is
3441 a valid backup copy in case there is a power failure during
3442 a "saveenv" operation.
3444 BE CAREFUL! Any changes to the flash layout, and some changes to the
3445 source code will make it necessary to adapt <board>/u-boot.lds*
3449 - CONFIG_ENV_IS_IN_NVRAM:
3451 Define this if you have some non-volatile memory device
3452 (NVRAM, battery buffered SRAM) which you want to use for the
3458 These two #defines are used to determine the memory area you
3459 want to use for environment. It is assumed that this memory
3460 can just be read and written to, without any special
3463 BE CAREFUL! The first access to the environment happens quite early
3464 in U-Boot initalization (when we try to get the setting of for the
3465 console baudrate). You *MUST* have mapped your NVRAM area then, or
3468 Please note that even with NVRAM we still use a copy of the
3469 environment in RAM: we could work on NVRAM directly, but we want to
3470 keep settings there always unmodified except somebody uses "saveenv"
3471 to save the current settings.
3474 - CONFIG_ENV_IS_IN_EEPROM:
3476 Use this if you have an EEPROM or similar serial access
3477 device and a driver for it.
3479 - CONFIG_ENV_OFFSET:
3482 These two #defines specify the offset and size of the
3483 environment area within the total memory of your EEPROM.
3485 - CONFIG_SYS_I2C_EEPROM_ADDR:
3486 If defined, specified the chip address of the EEPROM device.
3487 The default address is zero.
3489 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3490 If defined, the number of bits used to address bytes in a
3491 single page in the EEPROM device. A 64 byte page, for example
3492 would require six bits.
3494 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3495 If defined, the number of milliseconds to delay between
3496 page writes. The default is zero milliseconds.
3498 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3499 The length in bytes of the EEPROM memory array address. Note
3500 that this is NOT the chip address length!
3502 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3503 EEPROM chips that implement "address overflow" are ones
3504 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3505 address and the extra bits end up in the "chip address" bit
3506 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3509 Note that we consider the length of the address field to
3510 still be one byte because the extra address bits are hidden
3511 in the chip address.
3513 - CONFIG_SYS_EEPROM_SIZE:
3514 The size in bytes of the EEPROM device.
3516 - CONFIG_ENV_EEPROM_IS_ON_I2C
3517 define this, if you have I2C and SPI activated, and your
3518 EEPROM, which holds the environment, is on the I2C bus.
3520 - CONFIG_I2C_ENV_EEPROM_BUS
3521 if you have an Environment on an EEPROM reached over
3522 I2C muxes, you can define here, how to reach this
3523 EEPROM. For example:
3525 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3527 EEPROM which holds the environment, is reached over
3528 a pca9547 i2c mux with address 0x70, channel 3.
3530 - CONFIG_ENV_IS_IN_DATAFLASH:
3532 Define this if you have a DataFlash memory device which you
3533 want to use for the environment.
3535 - CONFIG_ENV_OFFSET:
3539 These three #defines specify the offset and size of the
3540 environment area within the total memory of your DataFlash placed
3541 at the specified address.
3543 - CONFIG_ENV_IS_IN_REMOTE:
3545 Define this if you have a remote memory space which you
3546 want to use for the local device's environment.
3551 These two #defines specify the address and size of the
3552 environment area within the remote memory space. The
3553 local device can get the environment from remote memory
3554 space by SRIO or PCIE links.
3556 BE CAREFUL! For some special cases, the local device can not use
3557 "saveenv" command. For example, the local device will get the
3558 environment stored in a remote NOR flash by SRIO or PCIE link,
3559 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3561 - CONFIG_ENV_IS_IN_NAND:
3563 Define this if you have a NAND device which you want to use
3564 for the environment.
3566 - CONFIG_ENV_OFFSET:
3569 These two #defines specify the offset and size of the environment
3570 area within the first NAND device. CONFIG_ENV_OFFSET must be
3571 aligned to an erase block boundary.
3573 - CONFIG_ENV_OFFSET_REDUND (optional):
3575 This setting describes a second storage area of CONFIG_ENV_SIZE
3576 size used to hold a redundant copy of the environment data, so
3577 that there is a valid backup copy in case there is a power failure
3578 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3579 aligned to an erase block boundary.
3581 - CONFIG_ENV_RANGE (optional):
3583 Specifies the length of the region in which the environment
3584 can be written. This should be a multiple of the NAND device's
3585 block size. Specifying a range with more erase blocks than
3586 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3587 the range to be avoided.
3589 - CONFIG_ENV_OFFSET_OOB (optional):
3591 Enables support for dynamically retrieving the offset of the
3592 environment from block zero's out-of-band data. The
3593 "nand env.oob" command can be used to record this offset.
3594 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3595 using CONFIG_ENV_OFFSET_OOB.
3597 - CONFIG_NAND_ENV_DST
3599 Defines address in RAM to which the nand_spl code should copy the
3600 environment. If redundant environment is used, it will be copied to
3601 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3603 - CONFIG_ENV_IS_IN_UBI:
3605 Define this if you have an UBI volume that you want to use for the
3606 environment. This has the benefit of wear-leveling the environment
3607 accesses, which is important on NAND.
3609 - CONFIG_ENV_UBI_PART:
3611 Define this to a string that is the mtd partition containing the UBI.
3613 - CONFIG_ENV_UBI_VOLUME:
3615 Define this to the name of the volume that you want to store the
3618 - CONFIG_ENV_UBI_VOLUME_REDUND:
3620 Define this to the name of another volume to store a second copy of
3621 the environment in. This will enable redundant environments in UBI.
3622 It is assumed that both volumes are in the same MTD partition.
3624 - CONFIG_UBI_SILENCE_MSG
3625 - CONFIG_UBIFS_SILENCE_MSG
3627 You will probably want to define these to avoid a really noisy system
3628 when storing the env in UBI.
3630 - CONFIG_SYS_SPI_INIT_OFFSET
3632 Defines offset to the initial SPI buffer area in DPRAM. The
3633 area is used at an early stage (ROM part) if the environment
3634 is configured to reside in the SPI EEPROM: We need a 520 byte
3635 scratch DPRAM area. It is used between the two initialization
3636 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3637 to be a good choice since it makes it far enough from the
3638 start of the data area as well as from the stack pointer.
3640 Please note that the environment is read-only until the monitor
3641 has been relocated to RAM and a RAM copy of the environment has been
3642 created; also, when using EEPROM you will have to use getenv_f()
3643 until then to read environment variables.
3645 The environment is protected by a CRC32 checksum. Before the monitor
3646 is relocated into RAM, as a result of a bad CRC you will be working
3647 with the compiled-in default environment - *silently*!!! [This is
3648 necessary, because the first environment variable we need is the
3649 "baudrate" setting for the console - if we have a bad CRC, we don't
3650 have any device yet where we could complain.]
3652 Note: once the monitor has been relocated, then it will complain if
3653 the default environment is used; a new CRC is computed as soon as you
3654 use the "saveenv" command to store a valid environment.
3656 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3657 Echo the inverted Ethernet link state to the fault LED.
3659 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3660 also needs to be defined.
3662 - CONFIG_SYS_FAULT_MII_ADDR:
3663 MII address of the PHY to check for the Ethernet link state.
3665 - CONFIG_NS16550_MIN_FUNCTIONS:
3666 Define this if you desire to only have use of the NS16550_init
3667 and NS16550_putc functions for the serial driver located at
3668 drivers/serial/ns16550.c. This option is useful for saving
3669 space for already greatly restricted images, including but not
3670 limited to NAND_SPL configurations.
3672 - CONFIG_DISPLAY_BOARDINFO
3673 Display information about the board that U-Boot is running on
3674 when U-Boot starts up. The board function checkboard() is called
3677 - CONFIG_DISPLAY_BOARDINFO_LATE
3678 Similar to the previous option, but display this information
3679 later, once stdio is running and output goes to the LCD, if
3682 Low Level (hardware related) configuration options:
3683 ---------------------------------------------------
3685 - CONFIG_SYS_CACHELINE_SIZE:
3686 Cache Line Size of the CPU.
3688 - CONFIG_SYS_DEFAULT_IMMR:
3689 Default address of the IMMR after system reset.
3691 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3692 and RPXsuper) to be able to adjust the position of
3693 the IMMR register after a reset.
3695 - CONFIG_SYS_CCSRBAR_DEFAULT:
3696 Default (power-on reset) physical address of CCSR on Freescale
3699 - CONFIG_SYS_CCSRBAR:
3700 Virtual address of CCSR. On a 32-bit build, this is typically
3701 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3703 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3704 for cross-platform code that uses that macro instead.
3706 - CONFIG_SYS_CCSRBAR_PHYS:
3707 Physical address of CCSR. CCSR can be relocated to a new
3708 physical address, if desired. In this case, this macro should
3709 be set to that address. Otherwise, it should be set to the
3710 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3711 is typically relocated on 36-bit builds. It is recommended
3712 that this macro be defined via the _HIGH and _LOW macros:
3714 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3715 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3717 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3718 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3719 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3720 used in assembly code, so it must not contain typecasts or
3721 integer size suffixes (e.g. "ULL").
3723 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3724 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3725 used in assembly code, so it must not contain typecasts or
3726 integer size suffixes (e.g. "ULL").
3728 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3729 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3730 forced to a value that ensures that CCSR is not relocated.
3732 - Floppy Disk Support:
3733 CONFIG_SYS_FDC_DRIVE_NUMBER
3735 the default drive number (default value 0)
3737 CONFIG_SYS_ISA_IO_STRIDE
3739 defines the spacing between FDC chipset registers
3742 CONFIG_SYS_ISA_IO_OFFSET
3744 defines the offset of register from address. It
3745 depends on which part of the data bus is connected to
3746 the FDC chipset. (default value 0)
3748 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3749 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3752 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3753 fdc_hw_init() is called at the beginning of the FDC
3754 setup. fdc_hw_init() must be provided by the board
3755 source code. It is used to make hardware dependant
3759 Most IDE controllers were designed to be connected with PCI
3760 interface. Only few of them were designed for AHB interface.
3761 When software is doing ATA command and data transfer to
3762 IDE devices through IDE-AHB controller, some additional
3763 registers accessing to these kind of IDE-AHB controller
3766 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3767 DO NOT CHANGE unless you know exactly what you're
3768 doing! (11-4) [MPC8xx/82xx systems only]
3770 - CONFIG_SYS_INIT_RAM_ADDR:
3772 Start address of memory area that can be used for
3773 initial data and stack; please note that this must be
3774 writable memory that is working WITHOUT special
3775 initialization, i. e. you CANNOT use normal RAM which
3776 will become available only after programming the
3777 memory controller and running certain initialization
3780 U-Boot uses the following memory types:
3781 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3782 - MPC824X: data cache
3783 - PPC4xx: data cache
3785 - CONFIG_SYS_GBL_DATA_OFFSET:
3787 Offset of the initial data structure in the memory
3788 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3789 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3790 data is located at the end of the available space
3791 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3792 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3793 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3794 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3797 On the MPC824X (or other systems that use the data
3798 cache for initial memory) the address chosen for
3799 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3800 point to an otherwise UNUSED address space between
3801 the top of RAM and the start of the PCI space.
3803 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3805 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3807 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3809 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3811 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3813 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3815 - CONFIG_SYS_OR_TIMING_SDRAM:
3818 - CONFIG_SYS_MAMR_PTA:
3819 periodic timer for refresh
3821 - CONFIG_SYS_DER: Debug Event Register (37-47)
3823 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3824 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3825 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3826 CONFIG_SYS_BR1_PRELIM:
3827 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3829 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3830 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3831 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3832 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3834 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3835 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3836 Machine Mode Register and Memory Periodic Timer
3837 Prescaler definitions (SDRAM timing)
3839 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3840 enable I2C microcode relocation patch (MPC8xx);
3841 define relocation offset in DPRAM [DSP2]
3843 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3844 enable SMC microcode relocation patch (MPC8xx);
3845 define relocation offset in DPRAM [SMC1]
3847 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3848 enable SPI microcode relocation patch (MPC8xx);
3849 define relocation offset in DPRAM [SCC4]
3851 - CONFIG_SYS_USE_OSCCLK:
3852 Use OSCM clock mode on MBX8xx board. Be careful,
3853 wrong setting might damage your board. Read
3854 doc/README.MBX before setting this variable!
3856 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3857 Offset of the bootmode word in DPRAM used by post
3858 (Power On Self Tests). This definition overrides
3859 #define'd default value in commproc.h resp.
3862 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3863 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3864 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3865 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3866 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3867 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3868 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3869 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3870 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3872 - CONFIG_PCI_DISABLE_PCIE:
3873 Disable PCI-Express on systems where it is supported but not
3876 - CONFIG_PCI_ENUM_ONLY
3877 Only scan through and get the devices on the busses.
3878 Don't do any setup work, presumably because someone or
3879 something has already done it, and we don't need to do it
3880 a second time. Useful for platforms that are pre-booted
3881 by coreboot or similar.
3884 Chip has SRIO or not
3887 Board has SRIO 1 port available
3890 Board has SRIO 2 port available
3892 - CONFIG_SYS_SRIOn_MEM_VIRT:
3893 Virtual Address of SRIO port 'n' memory region
3895 - CONFIG_SYS_SRIOn_MEM_PHYS:
3896 Physical Address of SRIO port 'n' memory region
3898 - CONFIG_SYS_SRIOn_MEM_SIZE:
3899 Size of SRIO port 'n' memory region
3901 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3902 Defined to tell the NAND controller that the NAND chip is using
3904 Not all NAND drivers use this symbol.
3905 Example of drivers that use it:
3906 - drivers/mtd/nand/ndfc.c
3907 - drivers/mtd/nand/mxc_nand.c
3909 - CONFIG_SYS_NDFC_EBC0_CFG
3910 Sets the EBC0_CFG register for the NDFC. If not defined
3911 a default value will be used.
3914 Get DDR timing information from an I2C EEPROM. Common
3915 with pluggable memory modules such as SODIMMs
3918 I2C address of the SPD EEPROM
3920 - CONFIG_SYS_SPD_BUS_NUM
3921 If SPD EEPROM is on an I2C bus other than the first
3922 one, specify here. Note that the value must resolve
3923 to something your driver can deal with.
3925 - CONFIG_SYS_DDR_RAW_TIMING
3926 Get DDR timing information from other than SPD. Common with
3927 soldered DDR chips onboard without SPD. DDR raw timing
3928 parameters are extracted from datasheet and hard-coded into
3929 header files or board specific files.
3931 - CONFIG_FSL_DDR_INTERACTIVE
3932 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3934 - CONFIG_SYS_83XX_DDR_USES_CS0
3935 Only for 83xx systems. If specified, then DDR should
3936 be configured using CS0 and CS1 instead of CS2 and CS3.
3938 - CONFIG_ETHER_ON_FEC[12]
3939 Define to enable FEC[12] on a 8xx series processor.
3941 - CONFIG_FEC[12]_PHY
3942 Define to the hardcoded PHY address which corresponds
3943 to the given FEC; i. e.
3944 #define CONFIG_FEC1_PHY 4
3945 means that the PHY with address 4 is connected to FEC1
3947 When set to -1, means to probe for first available.
3949 - CONFIG_FEC[12]_PHY_NORXERR
3950 The PHY does not have a RXERR line (RMII only).
3951 (so program the FEC to ignore it).
3954 Enable RMII mode for all FECs.
3955 Note that this is a global option, we can't
3956 have one FEC in standard MII mode and another in RMII mode.
3958 - CONFIG_CRC32_VERIFY
3959 Add a verify option to the crc32 command.
3962 => crc32 -v <address> <count> <crc32>
3964 Where address/count indicate a memory area
3965 and crc32 is the correct crc32 which the
3969 Add the "loopw" memory command. This only takes effect if
3970 the memory commands are activated globally (CONFIG_CMD_MEM).
3973 Add the "mdc" and "mwc" memory commands. These are cyclic
3978 This command will print 4 bytes (10,11,12,13) each 500 ms.
3980 => mwc.l 100 12345678 10
3981 This command will write 12345678 to address 100 all 10 ms.
3983 This only takes effect if the memory commands are activated
3984 globally (CONFIG_CMD_MEM).
3986 - CONFIG_SKIP_LOWLEVEL_INIT
3987 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3988 low level initializations (like setting up the memory
3989 controller) are omitted and/or U-Boot does not
3990 relocate itself into RAM.
3992 Normally this variable MUST NOT be defined. The only
3993 exception is when U-Boot is loaded (to RAM) by some
3994 other boot loader or by a debugger which performs
3995 these initializations itself.
3998 Modifies the behaviour of start.S when compiling a loader
3999 that is executed before the actual U-Boot. E.g. when
4000 compiling a NAND SPL.
4002 - CONFIG_ARCH_MAP_SYSMEM
4003 Generally U-Boot (and in particular the md command) uses
4004 effective address. It is therefore not necessary to regard
4005 U-Boot address as virtual addresses that need to be translated
4006 to physical addresses. However, sandbox requires this, since
4007 it maintains its own little RAM buffer which contains all
4008 addressable memory. This option causes some memory accesses
4009 to be mapped through map_sysmem() / unmap_sysmem().
4011 - CONFIG_USE_ARCH_MEMCPY
4012 CONFIG_USE_ARCH_MEMSET
4013 If these options are used a optimized version of memcpy/memset will
4014 be used if available. These functions may be faster under some
4015 conditions but may increase the binary size.
4017 - CONFIG_X86_RESET_VECTOR
4018 If defined, the x86 reset vector code is included. This is not
4019 needed when U-Boot is running from Coreboot.
4022 Defines the MPU clock speed (in MHz).
4024 NOTE : currently only supported on AM335x platforms.
4026 Freescale QE/FMAN Firmware Support:
4027 -----------------------------------
4029 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4030 loading of "firmware", which is encoded in the QE firmware binary format.
4031 This firmware often needs to be loaded during U-Boot booting, so macros
4032 are used to identify the storage device (NOR flash, SPI, etc) and the address
4035 - CONFIG_SYS_QE_FMAN_FW_ADDR
4036 The address in the storage device where the firmware is located. The
4037 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4040 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4041 The maximum possible size of the firmware. The firmware binary format
4042 has a field that specifies the actual size of the firmware, but it
4043 might not be possible to read any part of the firmware unless some
4044 local storage is allocated to hold the entire firmware first.
4046 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4047 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4048 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4049 virtual address in NOR flash.
4051 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4052 Specifies that QE/FMAN firmware is located in NAND flash.
4053 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4055 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4056 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4057 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4059 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4060 Specifies that QE/FMAN firmware is located on the primary SPI
4061 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4063 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4064 Specifies that QE/FMAN firmware is located in the remote (master)
4065 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4066 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4067 window->master inbound window->master LAW->the ucode address in
4068 master's memory space.
4070 Building the Software:
4071 ======================
4073 Building U-Boot has been tested in several native build environments
4074 and in many different cross environments. Of course we cannot support
4075 all possibly existing versions of cross development tools in all
4076 (potentially obsolete) versions. In case of tool chain problems we
4077 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4078 which is extensively used to build and test U-Boot.
4080 If you are not using a native environment, it is assumed that you
4081 have GNU cross compiling tools available in your path. In this case,
4082 you must set the environment variable CROSS_COMPILE in your shell.
4083 Note that no changes to the Makefile or any other source files are
4084 necessary. For example using the ELDK on a 4xx CPU, please enter:
4086 $ CROSS_COMPILE=ppc_4xx-
4087 $ export CROSS_COMPILE
4089 Note: If you wish to generate Windows versions of the utilities in
4090 the tools directory you can use the MinGW toolchain
4091 (http://www.mingw.org). Set your HOST tools to the MinGW
4092 toolchain and execute 'make tools'. For example:
4094 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4096 Binaries such as tools/mkimage.exe will be created which can
4097 be executed on computers running Windows.
4099 U-Boot is intended to be simple to build. After installing the
4100 sources you must configure U-Boot for one specific board type. This
4105 where "NAME_config" is the name of one of the existing configu-
4106 rations; see boards.cfg for supported names.
4108 Note: for some board special configuration names may exist; check if
4109 additional information is available from the board vendor; for
4110 instance, the TQM823L systems are available without (standard)
4111 or with LCD support. You can select such additional "features"
4112 when choosing the configuration, i. e.
4115 - will configure for a plain TQM823L, i. e. no LCD support
4117 make TQM823L_LCD_config
4118 - will configure for a TQM823L with U-Boot console on LCD
4123 Finally, type "make all", and you should get some working U-Boot
4124 images ready for download to / installation on your system:
4126 - "u-boot.bin" is a raw binary image
4127 - "u-boot" is an image in ELF binary format
4128 - "u-boot.srec" is in Motorola S-Record format
4130 By default the build is performed locally and the objects are saved
4131 in the source directory. One of the two methods can be used to change
4132 this behavior and build U-Boot to some external directory:
4134 1. Add O= to the make command line invocations:
4136 make O=/tmp/build distclean
4137 make O=/tmp/build NAME_config
4138 make O=/tmp/build all
4140 2. Set environment variable BUILD_DIR to point to the desired location:
4142 export BUILD_DIR=/tmp/build
4147 Note that the command line "O=" setting overrides the BUILD_DIR environment
4151 Please be aware that the Makefiles assume you are using GNU make, so
4152 for instance on NetBSD you might need to use "gmake" instead of
4156 If the system board that you have is not listed, then you will need
4157 to port U-Boot to your hardware platform. To do this, follow these
4160 1. Add a new configuration option for your board to the toplevel
4161 "boards.cfg" file, using the existing entries as examples.
4162 Follow the instructions there to keep the boards in order.
4163 2. Create a new directory to hold your board specific code. Add any
4164 files you need. In your board directory, you will need at least
4165 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4166 3. Create a new configuration file "include/configs/<board>.h" for
4168 3. If you're porting U-Boot to a new CPU, then also create a new
4169 directory to hold your CPU specific code. Add any files you need.
4170 4. Run "make <board>_config" with your new name.
4171 5. Type "make", and you should get a working "u-boot.srec" file
4172 to be installed on your target system.
4173 6. Debug and solve any problems that might arise.
4174 [Of course, this last step is much harder than it sounds.]
4177 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4178 ==============================================================
4180 If you have modified U-Boot sources (for instance added a new board
4181 or support for new devices, a new CPU, etc.) you are expected to
4182 provide feedback to the other developers. The feedback normally takes
4183 the form of a "patch", i. e. a context diff against a certain (latest
4184 official or latest in the git repository) version of U-Boot sources.
4186 But before you submit such a patch, please verify that your modifi-
4187 cation did not break existing code. At least make sure that *ALL* of
4188 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4189 just run the "MAKEALL" script, which will configure and build U-Boot
4190 for ALL supported system. Be warned, this will take a while. You can
4191 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4192 environment variable to the script, i. e. to use the ELDK cross tools
4195 CROSS_COMPILE=ppc_8xx- MAKEALL
4197 or to build on a native PowerPC system you can type
4199 CROSS_COMPILE=' ' MAKEALL
4201 When using the MAKEALL script, the default behaviour is to build
4202 U-Boot in the source directory. This location can be changed by
4203 setting the BUILD_DIR environment variable. Also, for each target
4204 built, the MAKEALL script saves two log files (<target>.ERR and
4205 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4206 location can be changed by setting the MAKEALL_LOGDIR environment
4207 variable. For example:
4209 export BUILD_DIR=/tmp/build
4210 export MAKEALL_LOGDIR=/tmp/log
4211 CROSS_COMPILE=ppc_8xx- MAKEALL
4213 With the above settings build objects are saved in the /tmp/build,
4214 log files are saved in the /tmp/log and the source tree remains clean
4215 during the whole build process.
4218 See also "U-Boot Porting Guide" below.
4221 Monitor Commands - Overview:
4222 ============================
4224 go - start application at address 'addr'
4225 run - run commands in an environment variable
4226 bootm - boot application image from memory
4227 bootp - boot image via network using BootP/TFTP protocol
4228 bootz - boot zImage from memory
4229 tftpboot- boot image via network using TFTP protocol
4230 and env variables "ipaddr" and "serverip"
4231 (and eventually "gatewayip")
4232 tftpput - upload a file via network using TFTP protocol
4233 rarpboot- boot image via network using RARP/TFTP protocol
4234 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4235 loads - load S-Record file over serial line
4236 loadb - load binary file over serial line (kermit mode)
4238 mm - memory modify (auto-incrementing)
4239 nm - memory modify (constant address)
4240 mw - memory write (fill)
4242 cmp - memory compare
4243 crc32 - checksum calculation
4244 i2c - I2C sub-system
4245 sspi - SPI utility commands
4246 base - print or set address offset
4247 printenv- print environment variables
4248 setenv - set environment variables
4249 saveenv - save environment variables to persistent storage
4250 protect - enable or disable FLASH write protection
4251 erase - erase FLASH memory
4252 flinfo - print FLASH memory information
4253 nand - NAND memory operations (see doc/README.nand)
4254 bdinfo - print Board Info structure
4255 iminfo - print header information for application image
4256 coninfo - print console devices and informations
4257 ide - IDE sub-system
4258 loop - infinite loop on address range
4259 loopw - infinite write loop on address range
4260 mtest - simple RAM test
4261 icache - enable or disable instruction cache
4262 dcache - enable or disable data cache
4263 reset - Perform RESET of the CPU
4264 echo - echo args to console
4265 version - print monitor version
4266 help - print online help
4267 ? - alias for 'help'
4270 Monitor Commands - Detailed Description:
4271 ========================================
4275 For now: just type "help <command>".
4278 Environment Variables:
4279 ======================
4281 U-Boot supports user configuration using Environment Variables which
4282 can be made persistent by saving to Flash memory.
4284 Environment Variables are set using "setenv", printed using
4285 "printenv", and saved to Flash using "saveenv". Using "setenv"
4286 without a value can be used to delete a variable from the
4287 environment. As long as you don't save the environment you are
4288 working with an in-memory copy. In case the Flash area containing the
4289 environment is erased by accident, a default environment is provided.
4291 Some configuration options can be set using Environment Variables.
4293 List of environment variables (most likely not complete):
4295 baudrate - see CONFIG_BAUDRATE
4297 bootdelay - see CONFIG_BOOTDELAY
4299 bootcmd - see CONFIG_BOOTCOMMAND
4301 bootargs - Boot arguments when booting an RTOS image
4303 bootfile - Name of the image to load with TFTP
4305 bootm_low - Memory range available for image processing in the bootm
4306 command can be restricted. This variable is given as
4307 a hexadecimal number and defines lowest address allowed
4308 for use by the bootm command. See also "bootm_size"
4309 environment variable. Address defined by "bootm_low" is
4310 also the base of the initial memory mapping for the Linux
4311 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4314 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4315 This variable is given as a hexadecimal number and it
4316 defines the size of the memory region starting at base
4317 address bootm_low that is accessible by the Linux kernel
4318 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4319 as the default value if it is defined, and bootm_size is
4322 bootm_size - Memory range available for image processing in the bootm
4323 command can be restricted. This variable is given as
4324 a hexadecimal number and defines the size of the region
4325 allowed for use by the bootm command. See also "bootm_low"
4326 environment variable.
4328 updatefile - Location of the software update file on a TFTP server, used
4329 by the automatic software update feature. Please refer to
4330 documentation in doc/README.update for more details.
4332 autoload - if set to "no" (any string beginning with 'n'),
4333 "bootp" will just load perform a lookup of the
4334 configuration from the BOOTP server, but not try to
4335 load any image using TFTP
4337 autostart - if set to "yes", an image loaded using the "bootp",
4338 "rarpboot", "tftpboot" or "diskboot" commands will
4339 be automatically started (by internally calling
4342 If set to "no", a standalone image passed to the
4343 "bootm" command will be copied to the load address
4344 (and eventually uncompressed), but NOT be started.
4345 This can be used to load and uncompress arbitrary
4348 fdt_high - if set this restricts the maximum address that the
4349 flattened device tree will be copied into upon boot.
4350 For example, if you have a system with 1 GB memory
4351 at physical address 0x10000000, while Linux kernel
4352 only recognizes the first 704 MB as low memory, you
4353 may need to set fdt_high as 0x3C000000 to have the
4354 device tree blob be copied to the maximum address
4355 of the 704 MB low memory, so that Linux kernel can
4356 access it during the boot procedure.
4358 If this is set to the special value 0xFFFFFFFF then
4359 the fdt will not be copied at all on boot. For this
4360 to work it must reside in writable memory, have
4361 sufficient padding on the end of it for u-boot to
4362 add the information it needs into it, and the memory
4363 must be accessible by the kernel.
4365 fdtcontroladdr- if set this is the address of the control flattened
4366 device tree used by U-Boot when CONFIG_OF_CONTROL is
4369 i2cfast - (PPC405GP|PPC405EP only)
4370 if set to 'y' configures Linux I2C driver for fast
4371 mode (400kHZ). This environment variable is used in
4372 initialization code. So, for changes to be effective
4373 it must be saved and board must be reset.
4375 initrd_high - restrict positioning of initrd images:
4376 If this variable is not set, initrd images will be
4377 copied to the highest possible address in RAM; this
4378 is usually what you want since it allows for
4379 maximum initrd size. If for some reason you want to
4380 make sure that the initrd image is loaded below the
4381 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4382 variable to a value of "no" or "off" or "0".
4383 Alternatively, you can set it to a maximum upper
4384 address to use (U-Boot will still check that it
4385 does not overwrite the U-Boot stack and data).
4387 For instance, when you have a system with 16 MB
4388 RAM, and want to reserve 4 MB from use by Linux,
4389 you can do this by adding "mem=12M" to the value of
4390 the "bootargs" variable. However, now you must make
4391 sure that the initrd image is placed in the first
4392 12 MB as well - this can be done with
4394 setenv initrd_high 00c00000
4396 If you set initrd_high to 0xFFFFFFFF, this is an
4397 indication to U-Boot that all addresses are legal
4398 for the Linux kernel, including addresses in flash
4399 memory. In this case U-Boot will NOT COPY the
4400 ramdisk at all. This may be useful to reduce the
4401 boot time on your system, but requires that this
4402 feature is supported by your Linux kernel.
4404 ipaddr - IP address; needed for tftpboot command
4406 loadaddr - Default load address for commands like "bootp",
4407 "rarpboot", "tftpboot", "loadb" or "diskboot"
4409 loads_echo - see CONFIG_LOADS_ECHO
4411 serverip - TFTP server IP address; needed for tftpboot command
4413 bootretry - see CONFIG_BOOT_RETRY_TIME
4415 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4417 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4419 ethprime - controls which interface is used first.
4421 ethact - controls which interface is currently active.
4422 For example you can do the following
4424 => setenv ethact FEC
4425 => ping 192.168.0.1 # traffic sent on FEC
4426 => setenv ethact SCC
4427 => ping 10.0.0.1 # traffic sent on SCC
4429 ethrotate - When set to "no" U-Boot does not go through all
4430 available network interfaces.
4431 It just stays at the currently selected interface.
4433 netretry - When set to "no" each network operation will
4434 either succeed or fail without retrying.
4435 When set to "once" the network operation will
4436 fail when all the available network interfaces
4437 are tried once without success.
4438 Useful on scripts which control the retry operation
4441 npe_ucode - set load address for the NPE microcode
4443 tftpsrcport - If this is set, the value is used for TFTP's
4446 tftpdstport - If this is set, the value is used for TFTP's UDP
4447 destination port instead of the Well Know Port 69.
4449 tftpblocksize - Block size to use for TFTP transfers; if not set,
4450 we use the TFTP server's default block size
4452 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4453 seconds, minimum value is 1000 = 1 second). Defines
4454 when a packet is considered to be lost so it has to
4455 be retransmitted. The default is 5000 = 5 seconds.
4456 Lowering this value may make downloads succeed
4457 faster in networks with high packet loss rates or
4458 with unreliable TFTP servers.
4460 vlan - When set to a value < 4095 the traffic over
4461 Ethernet is encapsulated/received over 802.1q
4464 The following image location variables contain the location of images
4465 used in booting. The "Image" column gives the role of the image and is
4466 not an environment variable name. The other columns are environment
4467 variable names. "File Name" gives the name of the file on a TFTP
4468 server, "RAM Address" gives the location in RAM the image will be
4469 loaded to, and "Flash Location" gives the image's address in NOR
4470 flash or offset in NAND flash.
4472 *Note* - these variables don't have to be defined for all boards, some
4473 boards currenlty use other variables for these purposes, and some
4474 boards use these variables for other purposes.
4476 Image File Name RAM Address Flash Location
4477 ----- --------- ----------- --------------
4478 u-boot u-boot u-boot_addr_r u-boot_addr
4479 Linux kernel bootfile kernel_addr_r kernel_addr
4480 device tree blob fdtfile fdt_addr_r fdt_addr
4481 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4483 The following environment variables may be used and automatically
4484 updated by the network boot commands ("bootp" and "rarpboot"),
4485 depending the information provided by your boot server:
4487 bootfile - see above
4488 dnsip - IP address of your Domain Name Server
4489 dnsip2 - IP address of your secondary Domain Name Server
4490 gatewayip - IP address of the Gateway (Router) to use
4491 hostname - Target hostname
4493 netmask - Subnet Mask
4494 rootpath - Pathname of the root filesystem on the NFS server
4495 serverip - see above
4498 There are two special Environment Variables:
4500 serial# - contains hardware identification information such
4501 as type string and/or serial number
4502 ethaddr - Ethernet address
4504 These variables can be set only once (usually during manufacturing of
4505 the board). U-Boot refuses to delete or overwrite these variables
4506 once they have been set once.
4509 Further special Environment Variables:
4511 ver - Contains the U-Boot version string as printed
4512 with the "version" command. This variable is
4513 readonly (see CONFIG_VERSION_VARIABLE).
4516 Please note that changes to some configuration parameters may take
4517 only effect after the next boot (yes, that's just like Windoze :-).
4520 Callback functions for environment variables:
4521 ---------------------------------------------
4523 For some environment variables, the behavior of u-boot needs to change
4524 when their values are changed. This functionailty allows functions to
4525 be associated with arbitrary variables. On creation, overwrite, or
4526 deletion, the callback will provide the opportunity for some side
4527 effect to happen or for the change to be rejected.
4529 The callbacks are named and associated with a function using the
4530 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4532 These callbacks are associated with variables in one of two ways. The
4533 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4534 in the board configuration to a string that defines a list of
4535 associations. The list must be in the following format:
4537 entry = variable_name[:callback_name]
4540 If the callback name is not specified, then the callback is deleted.
4541 Spaces are also allowed anywhere in the list.
4543 Callbacks can also be associated by defining the ".callbacks" variable
4544 with the same list format above. Any association in ".callbacks" will
4545 override any association in the static list. You can define
4546 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4547 ".callbacks" envirnoment variable in the default or embedded environment.
4550 Command Line Parsing:
4551 =====================
4553 There are two different command line parsers available with U-Boot:
4554 the old "simple" one, and the much more powerful "hush" shell:
4556 Old, simple command line parser:
4557 --------------------------------
4559 - supports environment variables (through setenv / saveenv commands)
4560 - several commands on one line, separated by ';'
4561 - variable substitution using "... ${name} ..." syntax
4562 - special characters ('$', ';') can be escaped by prefixing with '\',
4564 setenv bootcmd bootm \${address}
4565 - You can also escape text by enclosing in single apostrophes, for example:
4566 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4571 - similar to Bourne shell, with control structures like
4572 if...then...else...fi, for...do...done; while...do...done,
4573 until...do...done, ...
4574 - supports environment ("global") variables (through setenv / saveenv
4575 commands) and local shell variables (through standard shell syntax
4576 "name=value"); only environment variables can be used with "run"
4582 (1) If a command line (or an environment variable executed by a "run"
4583 command) contains several commands separated by semicolon, and
4584 one of these commands fails, then the remaining commands will be
4587 (2) If you execute several variables with one call to run (i. e.
4588 calling run with a list of variables as arguments), any failing
4589 command will cause "run" to terminate, i. e. the remaining
4590 variables are not executed.
4592 Note for Redundant Ethernet Interfaces:
4593 =======================================
4595 Some boards come with redundant Ethernet interfaces; U-Boot supports
4596 such configurations and is capable of automatic selection of a
4597 "working" interface when needed. MAC assignment works as follows:
4599 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4600 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4601 "eth1addr" (=>eth1), "eth2addr", ...
4603 If the network interface stores some valid MAC address (for instance
4604 in SROM), this is used as default address if there is NO correspon-
4605 ding setting in the environment; if the corresponding environment
4606 variable is set, this overrides the settings in the card; that means:
4608 o If the SROM has a valid MAC address, and there is no address in the
4609 environment, the SROM's address is used.
4611 o If there is no valid address in the SROM, and a definition in the
4612 environment exists, then the value from the environment variable is
4615 o If both the SROM and the environment contain a MAC address, and
4616 both addresses are the same, this MAC address is used.
4618 o If both the SROM and the environment contain a MAC address, and the
4619 addresses differ, the value from the environment is used and a
4622 o If neither SROM nor the environment contain a MAC address, an error
4625 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4626 will be programmed into hardware as part of the initialization process. This
4627 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4628 The naming convention is as follows:
4629 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4634 U-Boot is capable of booting (and performing other auxiliary operations on)
4635 images in two formats:
4637 New uImage format (FIT)
4638 -----------------------
4640 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4641 to Flattened Device Tree). It allows the use of images with multiple
4642 components (several kernels, ramdisks, etc.), with contents protected by
4643 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4649 Old image format is based on binary files which can be basically anything,
4650 preceded by a special header; see the definitions in include/image.h for
4651 details; basically, the header defines the following image properties:
4653 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4654 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4655 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4656 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4658 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4659 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4660 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4661 * Compression Type (uncompressed, gzip, bzip2)
4667 The header is marked by a special Magic Number, and both the header
4668 and the data portions of the image are secured against corruption by
4675 Although U-Boot should support any OS or standalone application
4676 easily, the main focus has always been on Linux during the design of
4679 U-Boot includes many features that so far have been part of some
4680 special "boot loader" code within the Linux kernel. Also, any
4681 "initrd" images to be used are no longer part of one big Linux image;
4682 instead, kernel and "initrd" are separate images. This implementation
4683 serves several purposes:
4685 - the same features can be used for other OS or standalone
4686 applications (for instance: using compressed images to reduce the
4687 Flash memory footprint)
4689 - it becomes much easier to port new Linux kernel versions because
4690 lots of low-level, hardware dependent stuff are done by U-Boot
4692 - the same Linux kernel image can now be used with different "initrd"
4693 images; of course this also means that different kernel images can
4694 be run with the same "initrd". This makes testing easier (you don't
4695 have to build a new "zImage.initrd" Linux image when you just
4696 change a file in your "initrd"). Also, a field-upgrade of the
4697 software is easier now.
4703 Porting Linux to U-Boot based systems:
4704 ---------------------------------------
4706 U-Boot cannot save you from doing all the necessary modifications to
4707 configure the Linux device drivers for use with your target hardware
4708 (no, we don't intend to provide a full virtual machine interface to
4711 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4713 Just make sure your machine specific header file (for instance
4714 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4715 Information structure as we define in include/asm-<arch>/u-boot.h,
4716 and make sure that your definition of IMAP_ADDR uses the same value
4717 as your U-Boot configuration in CONFIG_SYS_IMMR.
4720 Configuring the Linux kernel:
4721 -----------------------------
4723 No specific requirements for U-Boot. Make sure you have some root
4724 device (initial ramdisk, NFS) for your target system.
4727 Building a Linux Image:
4728 -----------------------
4730 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4731 not used. If you use recent kernel source, a new build target
4732 "uImage" will exist which automatically builds an image usable by
4733 U-Boot. Most older kernels also have support for a "pImage" target,
4734 which was introduced for our predecessor project PPCBoot and uses a
4735 100% compatible format.
4744 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4745 encapsulate a compressed Linux kernel image with header information,
4746 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4748 * build a standard "vmlinux" kernel image (in ELF binary format):
4750 * convert the kernel into a raw binary image:
4752 ${CROSS_COMPILE}-objcopy -O binary \
4753 -R .note -R .comment \
4754 -S vmlinux linux.bin
4756 * compress the binary image:
4760 * package compressed binary image for U-Boot:
4762 mkimage -A ppc -O linux -T kernel -C gzip \
4763 -a 0 -e 0 -n "Linux Kernel Image" \
4764 -d linux.bin.gz uImage
4767 The "mkimage" tool can also be used to create ramdisk images for use
4768 with U-Boot, either separated from the Linux kernel image, or
4769 combined into one file. "mkimage" encapsulates the images with a 64
4770 byte header containing information about target architecture,
4771 operating system, image type, compression method, entry points, time
4772 stamp, CRC32 checksums, etc.
4774 "mkimage" can be called in two ways: to verify existing images and
4775 print the header information, or to build new images.
4777 In the first form (with "-l" option) mkimage lists the information
4778 contained in the header of an existing U-Boot image; this includes
4779 checksum verification:
4781 tools/mkimage -l image
4782 -l ==> list image header information
4784 The second form (with "-d" option) is used to build a U-Boot image
4785 from a "data file" which is used as image payload:
4787 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4788 -n name -d data_file image
4789 -A ==> set architecture to 'arch'
4790 -O ==> set operating system to 'os'
4791 -T ==> set image type to 'type'
4792 -C ==> set compression type 'comp'
4793 -a ==> set load address to 'addr' (hex)
4794 -e ==> set entry point to 'ep' (hex)
4795 -n ==> set image name to 'name'
4796 -d ==> use image data from 'datafile'
4798 Right now, all Linux kernels for PowerPC systems use the same load
4799 address (0x00000000), but the entry point address depends on the
4802 - 2.2.x kernels have the entry point at 0x0000000C,
4803 - 2.3.x and later kernels have the entry point at 0x00000000.
4805 So a typical call to build a U-Boot image would read:
4807 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4808 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4809 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4810 > examples/uImage.TQM850L
4811 Image Name: 2.4.4 kernel for TQM850L
4812 Created: Wed Jul 19 02:34:59 2000
4813 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4814 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4815 Load Address: 0x00000000
4816 Entry Point: 0x00000000
4818 To verify the contents of the image (or check for corruption):
4820 -> tools/mkimage -l examples/uImage.TQM850L
4821 Image Name: 2.4.4 kernel for TQM850L
4822 Created: Wed Jul 19 02:34:59 2000
4823 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4824 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4825 Load Address: 0x00000000
4826 Entry Point: 0x00000000
4828 NOTE: for embedded systems where boot time is critical you can trade
4829 speed for memory and install an UNCOMPRESSED image instead: this
4830 needs more space in Flash, but boots much faster since it does not
4831 need to be uncompressed:
4833 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4834 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4835 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4836 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4837 > examples/uImage.TQM850L-uncompressed
4838 Image Name: 2.4.4 kernel for TQM850L
4839 Created: Wed Jul 19 02:34:59 2000
4840 Image Type: PowerPC Linux Kernel Image (uncompressed)
4841 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4842 Load Address: 0x00000000
4843 Entry Point: 0x00000000
4846 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4847 when your kernel is intended to use an initial ramdisk:
4849 -> tools/mkimage -n 'Simple Ramdisk Image' \
4850 > -A ppc -O linux -T ramdisk -C gzip \
4851 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4852 Image Name: Simple Ramdisk Image
4853 Created: Wed Jan 12 14:01:50 2000
4854 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4855 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4856 Load Address: 0x00000000
4857 Entry Point: 0x00000000
4860 Installing a Linux Image:
4861 -------------------------
4863 To downloading a U-Boot image over the serial (console) interface,
4864 you must convert the image to S-Record format:
4866 objcopy -I binary -O srec examples/image examples/image.srec
4868 The 'objcopy' does not understand the information in the U-Boot
4869 image header, so the resulting S-Record file will be relative to
4870 address 0x00000000. To load it to a given address, you need to
4871 specify the target address as 'offset' parameter with the 'loads'
4874 Example: install the image to address 0x40100000 (which on the
4875 TQM8xxL is in the first Flash bank):
4877 => erase 40100000 401FFFFF
4883 ## Ready for S-Record download ...
4884 ~>examples/image.srec
4885 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4887 15989 15990 15991 15992
4888 [file transfer complete]
4890 ## Start Addr = 0x00000000
4893 You can check the success of the download using the 'iminfo' command;
4894 this includes a checksum verification so you can be sure no data
4895 corruption happened:
4899 ## Checking Image at 40100000 ...
4900 Image Name: 2.2.13 for initrd on TQM850L
4901 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4902 Data Size: 335725 Bytes = 327 kB = 0 MB
4903 Load Address: 00000000
4904 Entry Point: 0000000c
4905 Verifying Checksum ... OK
4911 The "bootm" command is used to boot an application that is stored in
4912 memory (RAM or Flash). In case of a Linux kernel image, the contents
4913 of the "bootargs" environment variable is passed to the kernel as
4914 parameters. You can check and modify this variable using the
4915 "printenv" and "setenv" commands:
4918 => printenv bootargs
4919 bootargs=root=/dev/ram
4921 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4923 => printenv bootargs
4924 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4927 ## Booting Linux kernel at 40020000 ...
4928 Image Name: 2.2.13 for NFS on TQM850L
4929 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4930 Data Size: 381681 Bytes = 372 kB = 0 MB
4931 Load Address: 00000000
4932 Entry Point: 0000000c
4933 Verifying Checksum ... OK
4934 Uncompressing Kernel Image ... OK
4935 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
4936 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4937 time_init: decrementer frequency = 187500000/60
4938 Calibrating delay loop... 49.77 BogoMIPS
4939 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4942 If you want to boot a Linux kernel with initial RAM disk, you pass
4943 the memory addresses of both the kernel and the initrd image (PPBCOOT
4944 format!) to the "bootm" command:
4946 => imi 40100000 40200000
4948 ## Checking Image at 40100000 ...
4949 Image Name: 2.2.13 for initrd on TQM850L
4950 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4951 Data Size: 335725 Bytes = 327 kB = 0 MB
4952 Load Address: 00000000
4953 Entry Point: 0000000c
4954 Verifying Checksum ... OK
4956 ## Checking Image at 40200000 ...
4957 Image Name: Simple Ramdisk Image
4958 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4959 Data Size: 566530 Bytes = 553 kB = 0 MB
4960 Load Address: 00000000
4961 Entry Point: 00000000
4962 Verifying Checksum ... OK
4964 => bootm 40100000 40200000
4965 ## Booting Linux kernel at 40100000 ...
4966 Image Name: 2.2.13 for initrd on TQM850L
4967 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4968 Data Size: 335725 Bytes = 327 kB = 0 MB
4969 Load Address: 00000000
4970 Entry Point: 0000000c
4971 Verifying Checksum ... OK
4972 Uncompressing Kernel Image ... OK
4973 ## Loading RAMDisk Image at 40200000 ...
4974 Image Name: Simple Ramdisk Image
4975 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4976 Data Size: 566530 Bytes = 553 kB = 0 MB
4977 Load Address: 00000000
4978 Entry Point: 00000000
4979 Verifying Checksum ... OK
4980 Loading Ramdisk ... OK
4981 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
4982 Boot arguments: root=/dev/ram
4983 time_init: decrementer frequency = 187500000/60
4984 Calibrating delay loop... 49.77 BogoMIPS
4986 RAMDISK: Compressed image found at block 0
4987 VFS: Mounted root (ext2 filesystem).
4991 Boot Linux and pass a flat device tree:
4994 First, U-Boot must be compiled with the appropriate defines. See the section
4995 titled "Linux Kernel Interface" above for a more in depth explanation. The
4996 following is an example of how to start a kernel and pass an updated
5002 oft=oftrees/mpc8540ads.dtb
5003 => tftp $oftaddr $oft
5004 Speed: 1000, full duplex
5006 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5007 Filename 'oftrees/mpc8540ads.dtb'.
5008 Load address: 0x300000
5011 Bytes transferred = 4106 (100a hex)
5012 => tftp $loadaddr $bootfile
5013 Speed: 1000, full duplex
5015 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5017 Load address: 0x200000
5018 Loading:############
5020 Bytes transferred = 1029407 (fb51f hex)
5025 => bootm $loadaddr - $oftaddr
5026 ## Booting image at 00200000 ...
5027 Image Name: Linux-2.6.17-dirty
5028 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5029 Data Size: 1029343 Bytes = 1005.2 kB
5030 Load Address: 00000000
5031 Entry Point: 00000000
5032 Verifying Checksum ... OK
5033 Uncompressing Kernel Image ... OK
5034 Booting using flat device tree at 0x300000
5035 Using MPC85xx ADS machine description
5036 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5040 More About U-Boot Image Types:
5041 ------------------------------
5043 U-Boot supports the following image types:
5045 "Standalone Programs" are directly runnable in the environment
5046 provided by U-Boot; it is expected that (if they behave
5047 well) you can continue to work in U-Boot after return from
5048 the Standalone Program.
5049 "OS Kernel Images" are usually images of some Embedded OS which
5050 will take over control completely. Usually these programs
5051 will install their own set of exception handlers, device
5052 drivers, set up the MMU, etc. - this means, that you cannot
5053 expect to re-enter U-Boot except by resetting the CPU.
5054 "RAMDisk Images" are more or less just data blocks, and their
5055 parameters (address, size) are passed to an OS kernel that is
5057 "Multi-File Images" contain several images, typically an OS
5058 (Linux) kernel image and one or more data images like
5059 RAMDisks. This construct is useful for instance when you want
5060 to boot over the network using BOOTP etc., where the boot
5061 server provides just a single image file, but you want to get
5062 for instance an OS kernel and a RAMDisk image.
5064 "Multi-File Images" start with a list of image sizes, each
5065 image size (in bytes) specified by an "uint32_t" in network
5066 byte order. This list is terminated by an "(uint32_t)0".
5067 Immediately after the terminating 0 follow the images, one by
5068 one, all aligned on "uint32_t" boundaries (size rounded up to
5069 a multiple of 4 bytes).
5071 "Firmware Images" are binary images containing firmware (like
5072 U-Boot or FPGA images) which usually will be programmed to
5075 "Script files" are command sequences that will be executed by
5076 U-Boot's command interpreter; this feature is especially
5077 useful when you configure U-Boot to use a real shell (hush)
5078 as command interpreter.
5080 Booting the Linux zImage:
5081 -------------------------
5083 On some platforms, it's possible to boot Linux zImage. This is done
5084 using the "bootz" command. The syntax of "bootz" command is the same
5085 as the syntax of "bootm" command.
5087 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5088 kernel with raw initrd images. The syntax is slightly different, the
5089 address of the initrd must be augmented by it's size, in the following
5090 format: "<initrd addres>:<initrd size>".
5096 One of the features of U-Boot is that you can dynamically load and
5097 run "standalone" applications, which can use some resources of
5098 U-Boot like console I/O functions or interrupt services.
5100 Two simple examples are included with the sources:
5105 'examples/hello_world.c' contains a small "Hello World" Demo
5106 application; it is automatically compiled when you build U-Boot.
5107 It's configured to run at address 0x00040004, so you can play with it
5111 ## Ready for S-Record download ...
5112 ~>examples/hello_world.srec
5113 1 2 3 4 5 6 7 8 9 10 11 ...
5114 [file transfer complete]
5116 ## Start Addr = 0x00040004
5118 => go 40004 Hello World! This is a test.
5119 ## Starting application at 0x00040004 ...
5130 Hit any key to exit ...
5132 ## Application terminated, rc = 0x0
5134 Another example, which demonstrates how to register a CPM interrupt
5135 handler with the U-Boot code, can be found in 'examples/timer.c'.
5136 Here, a CPM timer is set up to generate an interrupt every second.
5137 The interrupt service routine is trivial, just printing a '.'
5138 character, but this is just a demo program. The application can be
5139 controlled by the following keys:
5141 ? - print current values og the CPM Timer registers
5142 b - enable interrupts and start timer
5143 e - stop timer and disable interrupts
5144 q - quit application
5147 ## Ready for S-Record download ...
5148 ~>examples/timer.srec
5149 1 2 3 4 5 6 7 8 9 10 11 ...
5150 [file transfer complete]
5152 ## Start Addr = 0x00040004
5155 ## Starting application at 0x00040004 ...
5158 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5161 [q, b, e, ?] Set interval 1000000 us
5164 [q, b, e, ?] ........
5165 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5168 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5171 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5174 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5176 [q, b, e, ?] ...Stopping timer
5178 [q, b, e, ?] ## Application terminated, rc = 0x0
5184 Over time, many people have reported problems when trying to use the
5185 "minicom" terminal emulation program for serial download. I (wd)
5186 consider minicom to be broken, and recommend not to use it. Under
5187 Unix, I recommend to use C-Kermit for general purpose use (and
5188 especially for kermit binary protocol download ("loadb" command), and
5189 use "cu" for S-Record download ("loads" command). See
5190 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5191 for help with kermit.
5194 Nevertheless, if you absolutely want to use it try adding this
5195 configuration to your "File transfer protocols" section:
5197 Name Program Name U/D FullScr IO-Red. Multi
5198 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5199 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5205 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5206 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5208 Building requires a cross environment; it is known to work on
5209 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5210 need gmake since the Makefiles are not compatible with BSD make).
5211 Note that the cross-powerpc package does not install include files;
5212 attempting to build U-Boot will fail because <machine/ansi.h> is
5213 missing. This file has to be installed and patched manually:
5215 # cd /usr/pkg/cross/powerpc-netbsd/include
5217 # ln -s powerpc machine
5218 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5219 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5221 Native builds *don't* work due to incompatibilities between native
5222 and U-Boot include files.
5224 Booting assumes that (the first part of) the image booted is a
5225 stage-2 loader which in turn loads and then invokes the kernel
5226 proper. Loader sources will eventually appear in the NetBSD source
5227 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5228 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5231 Implementation Internals:
5232 =========================
5234 The following is not intended to be a complete description of every
5235 implementation detail. However, it should help to understand the
5236 inner workings of U-Boot and make it easier to port it to custom
5240 Initial Stack, Global Data:
5241 ---------------------------
5243 The implementation of U-Boot is complicated by the fact that U-Boot
5244 starts running out of ROM (flash memory), usually without access to
5245 system RAM (because the memory controller is not initialized yet).
5246 This means that we don't have writable Data or BSS segments, and BSS
5247 is not initialized as zero. To be able to get a C environment working
5248 at all, we have to allocate at least a minimal stack. Implementation
5249 options for this are defined and restricted by the CPU used: Some CPU
5250 models provide on-chip memory (like the IMMR area on MPC8xx and
5251 MPC826x processors), on others (parts of) the data cache can be
5252 locked as (mis-) used as memory, etc.
5254 Chris Hallinan posted a good summary of these issues to the
5255 U-Boot mailing list:
5257 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5258 From: "Chris Hallinan" <clh@net1plus.com>
5259 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5262 Correct me if I'm wrong, folks, but the way I understand it
5263 is this: Using DCACHE as initial RAM for Stack, etc, does not
5264 require any physical RAM backing up the cache. The cleverness
5265 is that the cache is being used as a temporary supply of
5266 necessary storage before the SDRAM controller is setup. It's
5267 beyond the scope of this list to explain the details, but you
5268 can see how this works by studying the cache architecture and
5269 operation in the architecture and processor-specific manuals.
5271 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5272 is another option for the system designer to use as an
5273 initial stack/RAM area prior to SDRAM being available. Either
5274 option should work for you. Using CS 4 should be fine if your
5275 board designers haven't used it for something that would
5276 cause you grief during the initial boot! It is frequently not
5279 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5280 with your processor/board/system design. The default value
5281 you will find in any recent u-boot distribution in
5282 walnut.h should work for you. I'd set it to a value larger
5283 than your SDRAM module. If you have a 64MB SDRAM module, set
5284 it above 400_0000. Just make sure your board has no resources
5285 that are supposed to respond to that address! That code in
5286 start.S has been around a while and should work as is when
5287 you get the config right.
5292 It is essential to remember this, since it has some impact on the C
5293 code for the initialization procedures:
5295 * Initialized global data (data segment) is read-only. Do not attempt
5298 * Do not use any uninitialized global data (or implicitely initialized
5299 as zero data - BSS segment) at all - this is undefined, initiali-
5300 zation is performed later (when relocating to RAM).
5302 * Stack space is very limited. Avoid big data buffers or things like
5305 Having only the stack as writable memory limits means we cannot use
5306 normal global data to share information beween the code. But it
5307 turned out that the implementation of U-Boot can be greatly
5308 simplified by making a global data structure (gd_t) available to all
5309 functions. We could pass a pointer to this data as argument to _all_
5310 functions, but this would bloat the code. Instead we use a feature of
5311 the GCC compiler (Global Register Variables) to share the data: we
5312 place a pointer (gd) to the global data into a register which we
5313 reserve for this purpose.
5315 When choosing a register for such a purpose we are restricted by the
5316 relevant (E)ABI specifications for the current architecture, and by
5317 GCC's implementation.
5319 For PowerPC, the following registers have specific use:
5321 R2: reserved for system use
5322 R3-R4: parameter passing and return values
5323 R5-R10: parameter passing
5324 R13: small data area pointer
5328 (U-Boot also uses R12 as internal GOT pointer. r12
5329 is a volatile register so r12 needs to be reset when
5330 going back and forth between asm and C)
5332 ==> U-Boot will use R2 to hold a pointer to the global data
5334 Note: on PPC, we could use a static initializer (since the
5335 address of the global data structure is known at compile time),
5336 but it turned out that reserving a register results in somewhat
5337 smaller code - although the code savings are not that big (on
5338 average for all boards 752 bytes for the whole U-Boot image,
5339 624 text + 127 data).
5341 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5342 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5344 ==> U-Boot will use P3 to hold a pointer to the global data
5346 On ARM, the following registers are used:
5348 R0: function argument word/integer result
5349 R1-R3: function argument word
5351 R10: stack limit (used only if stack checking if enabled)
5352 R11: argument (frame) pointer
5353 R12: temporary workspace
5356 R15: program counter
5358 ==> U-Boot will use R8 to hold a pointer to the global data
5360 On Nios II, the ABI is documented here:
5361 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5363 ==> U-Boot will use gp to hold a pointer to the global data
5365 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5366 to access small data sections, so gp is free.
5368 On NDS32, the following registers are used:
5370 R0-R1: argument/return
5372 R15: temporary register for assembler
5373 R16: trampoline register
5374 R28: frame pointer (FP)
5375 R29: global pointer (GP)
5376 R30: link register (LP)
5377 R31: stack pointer (SP)
5378 PC: program counter (PC)
5380 ==> U-Boot will use R10 to hold a pointer to the global data
5382 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5383 or current versions of GCC may "optimize" the code too much.
5388 U-Boot runs in system state and uses physical addresses, i.e. the
5389 MMU is not used either for address mapping nor for memory protection.
5391 The available memory is mapped to fixed addresses using the memory
5392 controller. In this process, a contiguous block is formed for each
5393 memory type (Flash, SDRAM, SRAM), even when it consists of several
5394 physical memory banks.
5396 U-Boot is installed in the first 128 kB of the first Flash bank (on
5397 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5398 booting and sizing and initializing DRAM, the code relocates itself
5399 to the upper end of DRAM. Immediately below the U-Boot code some
5400 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5401 configuration setting]. Below that, a structure with global Board
5402 Info data is placed, followed by the stack (growing downward).
5404 Additionally, some exception handler code is copied to the low 8 kB
5405 of DRAM (0x00000000 ... 0x00001FFF).
5407 So a typical memory configuration with 16 MB of DRAM could look like
5410 0x0000 0000 Exception Vector code
5413 0x0000 2000 Free for Application Use
5419 0x00FB FF20 Monitor Stack (Growing downward)
5420 0x00FB FFAC Board Info Data and permanent copy of global data
5421 0x00FC 0000 Malloc Arena
5424 0x00FE 0000 RAM Copy of Monitor Code
5425 ... eventually: LCD or video framebuffer
5426 ... eventually: pRAM (Protected RAM - unchanged by reset)
5427 0x00FF FFFF [End of RAM]
5430 System Initialization:
5431 ----------------------
5433 In the reset configuration, U-Boot starts at the reset entry point
5434 (on most PowerPC systems at address 0x00000100). Because of the reset
5435 configuration for CS0# this is a mirror of the onboard Flash memory.
5436 To be able to re-map memory U-Boot then jumps to its link address.
5437 To be able to implement the initialization code in C, a (small!)
5438 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5439 which provide such a feature like MPC8xx or MPC8260), or in a locked
5440 part of the data cache. After that, U-Boot initializes the CPU core,
5441 the caches and the SIU.
5443 Next, all (potentially) available memory banks are mapped using a
5444 preliminary mapping. For example, we put them on 512 MB boundaries
5445 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5446 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5447 programmed for SDRAM access. Using the temporary configuration, a
5448 simple memory test is run that determines the size of the SDRAM
5451 When there is more than one SDRAM bank, and the banks are of
5452 different size, the largest is mapped first. For equal size, the first
5453 bank (CS2#) is mapped first. The first mapping is always for address
5454 0x00000000, with any additional banks following immediately to create
5455 contiguous memory starting from 0.
5457 Then, the monitor installs itself at the upper end of the SDRAM area
5458 and allocates memory for use by malloc() and for the global Board
5459 Info data; also, the exception vector code is copied to the low RAM
5460 pages, and the final stack is set up.
5462 Only after this relocation will you have a "normal" C environment;
5463 until that you are restricted in several ways, mostly because you are
5464 running from ROM, and because the code will have to be relocated to a
5468 U-Boot Porting Guide:
5469 ----------------------
5471 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5475 int main(int argc, char *argv[])
5477 sighandler_t no_more_time;
5479 signal(SIGALRM, no_more_time);
5480 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5482 if (available_money > available_manpower) {
5483 Pay consultant to port U-Boot;
5487 Download latest U-Boot source;
5489 Subscribe to u-boot mailing list;
5492 email("Hi, I am new to U-Boot, how do I get started?");
5495 Read the README file in the top level directory;
5496 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5497 Read applicable doc/*.README;
5498 Read the source, Luke;
5499 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5502 if (available_money > toLocalCurrency ($2500))
5505 Add a lot of aggravation and time;
5507 if (a similar board exists) { /* hopefully... */
5508 cp -a board/<similar> board/<myboard>
5509 cp include/configs/<similar>.h include/configs/<myboard>.h
5511 Create your own board support subdirectory;
5512 Create your own board include/configs/<myboard>.h file;
5514 Edit new board/<myboard> files
5515 Edit new include/configs/<myboard>.h
5520 Add / modify source code;
5524 email("Hi, I am having problems...");
5526 Send patch file to the U-Boot email list;
5527 if (reasonable critiques)
5528 Incorporate improvements from email list code review;
5530 Defend code as written;
5536 void no_more_time (int sig)
5545 All contributions to U-Boot should conform to the Linux kernel
5546 coding style; see the file "Documentation/CodingStyle" and the script
5547 "scripts/Lindent" in your Linux kernel source directory.
5549 Source files originating from a different project (for example the
5550 MTD subsystem) are generally exempt from these guidelines and are not
5551 reformated to ease subsequent migration to newer versions of those
5554 Please note that U-Boot is implemented in C (and to some small parts in
5555 Assembler); no C++ is used, so please do not use C++ style comments (//)
5558 Please also stick to the following formatting rules:
5559 - remove any trailing white space
5560 - use TAB characters for indentation and vertical alignment, not spaces
5561 - make sure NOT to use DOS '\r\n' line feeds
5562 - do not add more than 2 consecutive empty lines to source files
5563 - do not add trailing empty lines to source files
5565 Submissions which do not conform to the standards may be returned
5566 with a request to reformat the changes.
5572 Since the number of patches for U-Boot is growing, we need to
5573 establish some rules. Submissions which do not conform to these rules
5574 may be rejected, even when they contain important and valuable stuff.
5576 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5578 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5579 see http://lists.denx.de/mailman/listinfo/u-boot
5581 When you send a patch, please include the following information with
5584 * For bug fixes: a description of the bug and how your patch fixes
5585 this bug. Please try to include a way of demonstrating that the
5586 patch actually fixes something.
5588 * For new features: a description of the feature and your
5591 * A CHANGELOG entry as plaintext (separate from the patch)
5593 * For major contributions, your entry to the CREDITS file
5595 * When you add support for a new board, don't forget to add this
5596 board to the MAINTAINERS file, too.
5598 * If your patch adds new configuration options, don't forget to
5599 document these in the README file.
5601 * The patch itself. If you are using git (which is *strongly*
5602 recommended) you can easily generate the patch using the
5603 "git format-patch". If you then use "git send-email" to send it to
5604 the U-Boot mailing list, you will avoid most of the common problems
5605 with some other mail clients.
5607 If you cannot use git, use "diff -purN OLD NEW". If your version of
5608 diff does not support these options, then get the latest version of
5611 The current directory when running this command shall be the parent
5612 directory of the U-Boot source tree (i. e. please make sure that
5613 your patch includes sufficient directory information for the
5616 We prefer patches as plain text. MIME attachments are discouraged,
5617 and compressed attachments must not be used.
5619 * If one logical set of modifications affects or creates several
5620 files, all these changes shall be submitted in a SINGLE patch file.
5622 * Changesets that contain different, unrelated modifications shall be
5623 submitted as SEPARATE patches, one patch per changeset.
5628 * Before sending the patch, run the MAKEALL script on your patched
5629 source tree and make sure that no errors or warnings are reported
5630 for any of the boards.
5632 * Keep your modifications to the necessary minimum: A patch
5633 containing several unrelated changes or arbitrary reformats will be
5634 returned with a request to re-formatting / split it.
5636 * If you modify existing code, make sure that your new code does not
5637 add to the memory footprint of the code ;-) Small is beautiful!
5638 When adding new features, these should compile conditionally only
5639 (using #ifdef), and the resulting code with the new feature
5640 disabled must not need more memory than the old code without your
5643 * Remember that there is a size limit of 100 kB per message on the
5644 u-boot mailing list. Bigger patches will be moderated. If they are
5645 reasonable and not too big, they will be acknowledged. But patches
5646 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob