2 # (C) Copyright 2000 - 2012
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
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 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 CONFIG_ARM_ERRATA_716044
489 CONFIG_ARM_ERRATA_742230
490 CONFIG_ARM_ERRATA_743622
491 CONFIG_ARM_ERRATA_751472
493 If set, the workarounds for these ARM errata are applied early
494 during U-Boot startup. Note that these options force the
495 workarounds to be applied; no CPU-type/version detection
496 exists, unlike the similar options in the Linux kernel. Do not
497 set these options unless they apply!
502 The frequency of the timer returned by get_timer().
503 get_timer() must operate in milliseconds and this CONFIG
504 option must be set to 1000.
506 - Linux Kernel Interface:
509 U-Boot stores all clock information in Hz
510 internally. For binary compatibility with older Linux
511 kernels (which expect the clocks passed in the
512 bd_info data to be in MHz) the environment variable
513 "clocks_in_mhz" can be defined so that U-Boot
514 converts clock data to MHZ before passing it to the
516 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
517 "clocks_in_mhz=1" is automatically included in the
520 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
522 When transferring memsize parameter to linux, some versions
523 expect it to be in bytes, others in MB.
524 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
528 New kernel versions are expecting firmware settings to be
529 passed using flattened device trees (based on open firmware
533 * New libfdt-based support
534 * Adds the "fdt" command
535 * The bootm command automatically updates the fdt
537 OF_CPU - The proper name of the cpus node (only required for
538 MPC512X and MPC5xxx based boards).
539 OF_SOC - The proper name of the soc node (only required for
540 MPC512X and MPC5xxx based boards).
541 OF_TBCLK - The timebase frequency.
542 OF_STDOUT_PATH - The path to the console device
544 boards with QUICC Engines require OF_QE to set UCC MAC
547 CONFIG_OF_BOARD_SETUP
549 Board code has addition modification that it wants to make
550 to the flat device tree before handing it off to the kernel
554 This define fills in the correct boot CPU in the boot
555 param header, the default value is zero if undefined.
559 U-Boot can detect if an IDE device is present or not.
560 If not, and this new config option is activated, U-Boot
561 removes the ATA node from the DTS before booting Linux,
562 so the Linux IDE driver does not probe the device and
563 crash. This is needed for buggy hardware (uc101) where
564 no pull down resistor is connected to the signal IDE5V_DD7.
566 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
568 This setting is mandatory for all boards that have only one
569 machine type and must be used to specify the machine type
570 number as it appears in the ARM machine registry
571 (see http://www.arm.linux.org.uk/developer/machines/).
572 Only boards that have multiple machine types supported
573 in a single configuration file and the machine type is
574 runtime discoverable, do not have to use this setting.
576 - vxWorks boot parameters:
578 bootvx constructs a valid bootline using the following
579 environments variables: bootfile, ipaddr, serverip, hostname.
580 It loads the vxWorks image pointed bootfile.
582 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
583 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
584 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
585 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
587 CONFIG_SYS_VXWORKS_ADD_PARAMS
589 Add it at the end of the bootline. E.g "u=username pw=secret"
591 Note: If a "bootargs" environment is defined, it will overwride
592 the defaults discussed just above.
594 - Cache Configuration:
595 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
596 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
597 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
599 - Cache Configuration for ARM:
600 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
602 CONFIG_SYS_PL310_BASE - Physical base address of PL310
603 controller register space
608 Define this if you want support for Amba PrimeCell PL010 UARTs.
612 Define this if you want support for Amba PrimeCell PL011 UARTs.
616 If you have Amba PrimeCell PL011 UARTs, set this variable to
617 the clock speed of the UARTs.
621 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
622 define this to a list of base addresses for each (supported)
623 port. See e.g. include/configs/versatile.h
625 CONFIG_PL011_SERIAL_RLCR
627 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
628 have separate receive and transmit line control registers. Set
629 this variable to initialize the extra register.
631 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
633 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
634 boot loader that has already initialized the UART. Define this
635 variable to flush the UART at init time.
637 CONFIG_SYS_NS16550_BROKEN_TEMT
639 16550 UART set the Transmitter Empty (TEMT) Bit when all output
640 has finished and the transmitter is totally empty. U-Boot waits
641 for this bit to be set to initialize the serial console. On some
642 broken platforms this bit is not set in SPL making U-Boot to
643 hang while waiting for TEMT. Define this option to avoid it.
647 Depending on board, define exactly one serial port
648 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
649 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
650 console by defining CONFIG_8xx_CONS_NONE
652 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
653 port routines must be defined elsewhere
654 (i.e. serial_init(), serial_getc(), ...)
657 Enables console device for a color framebuffer. Needs following
658 defines (cf. smiLynxEM, i8042)
659 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
661 VIDEO_HW_RECTFILL graphic chip supports
664 VIDEO_HW_BITBLT graphic chip supports
665 bit-blit (cf. smiLynxEM)
666 VIDEO_VISIBLE_COLS visible pixel columns
668 VIDEO_VISIBLE_ROWS visible pixel rows
669 VIDEO_PIXEL_SIZE bytes per pixel
670 VIDEO_DATA_FORMAT graphic data format
671 (0-5, cf. cfb_console.c)
672 VIDEO_FB_ADRS framebuffer address
673 VIDEO_KBD_INIT_FCT keyboard int fct
674 (i.e. i8042_kbd_init())
675 VIDEO_TSTC_FCT test char fct
677 VIDEO_GETC_FCT get char fct
679 CONFIG_CONSOLE_CURSOR cursor drawing on/off
680 (requires blink timer
682 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
683 CONFIG_CONSOLE_TIME display time/date info in
685 (requires CONFIG_CMD_DATE)
686 CONFIG_VIDEO_LOGO display Linux logo in
688 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
689 linux_logo.h for logo.
690 Requires CONFIG_VIDEO_LOGO
691 CONFIG_CONSOLE_EXTRA_INFO
692 additional board info beside
695 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
696 a limited number of ANSI escape sequences (cursor control,
697 erase functions and limited graphics rendition control).
699 When CONFIG_CFB_CONSOLE is defined, video console is
700 default i/o. Serial console can be forced with
701 environment 'console=serial'.
703 When CONFIG_SILENT_CONSOLE is defined, all console
704 messages (by U-Boot and Linux!) can be silenced with
705 the "silent" environment variable. See
706 doc/README.silent for more information.
709 CONFIG_BAUDRATE - in bps
710 Select one of the baudrates listed in
711 CONFIG_SYS_BAUDRATE_TABLE, see below.
712 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
714 - Console Rx buffer length
715 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
716 the maximum receive buffer length for the SMC.
717 This option is actual only for 82xx and 8xx possible.
718 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
719 must be defined, to setup the maximum idle timeout for
722 - Pre-Console Buffer:
723 Prior to the console being initialised (i.e. serial UART
724 initialised etc) all console output is silently discarded.
725 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
726 buffer any console messages prior to the console being
727 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
728 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
729 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
730 bytes are output before the console is initialised, the
731 earlier bytes are discarded.
733 'Sane' compilers will generate smaller code if
734 CONFIG_PRE_CON_BUF_SZ is a power of 2
736 - Safe printf() functions
737 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
738 the printf() functions. These are defined in
739 include/vsprintf.h and include snprintf(), vsnprintf() and
740 so on. Code size increase is approximately 300-500 bytes.
741 If this option is not given then these functions will
742 silently discard their buffer size argument - this means
743 you are not getting any overflow checking in this case.
745 - Boot Delay: CONFIG_BOOTDELAY - in seconds
746 Delay before automatically booting the default image;
747 set to -1 to disable autoboot.
748 set to -2 to autoboot with no delay and not check for abort
749 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
751 See doc/README.autoboot for these options that
752 work with CONFIG_BOOTDELAY. None are required.
753 CONFIG_BOOT_RETRY_TIME
754 CONFIG_BOOT_RETRY_MIN
755 CONFIG_AUTOBOOT_KEYED
756 CONFIG_AUTOBOOT_PROMPT
757 CONFIG_AUTOBOOT_DELAY_STR
758 CONFIG_AUTOBOOT_STOP_STR
759 CONFIG_AUTOBOOT_DELAY_STR2
760 CONFIG_AUTOBOOT_STOP_STR2
761 CONFIG_ZERO_BOOTDELAY_CHECK
762 CONFIG_RESET_TO_RETRY
766 Only needed when CONFIG_BOOTDELAY is enabled;
767 define a command string that is automatically executed
768 when no character is read on the console interface
769 within "Boot Delay" after reset.
772 This can be used to pass arguments to the bootm
773 command. The value of CONFIG_BOOTARGS goes into the
774 environment value "bootargs".
776 CONFIG_RAMBOOT and CONFIG_NFSBOOT
777 The value of these goes into the environment as
778 "ramboot" and "nfsboot" respectively, and can be used
779 as a convenience, when switching between booting from
785 When this option is #defined, the existence of the
786 environment variable "preboot" will be checked
787 immediately before starting the CONFIG_BOOTDELAY
788 countdown and/or running the auto-boot command resp.
789 entering interactive mode.
791 This feature is especially useful when "preboot" is
792 automatically generated or modified. For an example
793 see the LWMON board specific code: here "preboot" is
794 modified when the user holds down a certain
795 combination of keys on the (special) keyboard when
798 - Serial Download Echo Mode:
800 If defined to 1, all characters received during a
801 serial download (using the "loads" command) are
802 echoed back. This might be needed by some terminal
803 emulations (like "cu"), but may as well just take
804 time on others. This setting #define's the initial
805 value of the "loads_echo" environment variable.
807 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
809 Select one of the baudrates listed in
810 CONFIG_SYS_BAUDRATE_TABLE, see below.
813 Monitor commands can be included or excluded
814 from the build by using the #include files
815 <config_cmd_all.h> and #undef'ing unwanted
816 commands, or using <config_cmd_default.h>
817 and augmenting with additional #define's
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_ASKENV * ask for env variable
824 CONFIG_CMD_BDI bdinfo
825 CONFIG_CMD_BEDBUG * Include BedBug Debugger
826 CONFIG_CMD_BMP * BMP support
827 CONFIG_CMD_BSP * Board specific commands
828 CONFIG_CMD_BOOTD bootd
829 CONFIG_CMD_CACHE * icache, dcache
830 CONFIG_CMD_CONSOLE coninfo
831 CONFIG_CMD_CRC32 * crc32
832 CONFIG_CMD_DATE * support for RTC, date/time...
833 CONFIG_CMD_DHCP * DHCP support
834 CONFIG_CMD_DIAG * Diagnostics
835 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
836 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
837 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
838 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
839 CONFIG_CMD_DTT * Digital Therm and Thermostat
840 CONFIG_CMD_ECHO echo arguments
841 CONFIG_CMD_EDITENV edit env variable
842 CONFIG_CMD_EEPROM * EEPROM read/write support
843 CONFIG_CMD_ELF * bootelf, bootvx
844 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
845 CONFIG_CMD_ENV_FLAGS * display details about env flags
846 CONFIG_CMD_EXPORTENV * export the environment
847 CONFIG_CMD_EXT2 * ext2 command support
848 CONFIG_CMD_EXT4 * ext4 command support
849 CONFIG_CMD_SAVEENV saveenv
850 CONFIG_CMD_FDC * Floppy Disk Support
851 CONFIG_CMD_FAT * FAT command support
852 CONFIG_CMD_FDOS * Dos diskette Support
853 CONFIG_CMD_FLASH flinfo, erase, protect
854 CONFIG_CMD_FPGA FPGA device initialization support
855 CONFIG_CMD_GETTIME * Get time since boot
856 CONFIG_CMD_GO * the 'go' command (exec code)
857 CONFIG_CMD_GREPENV * search environment
858 CONFIG_CMD_HASH * calculate hash / digest
859 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
860 CONFIG_CMD_I2C * I2C serial bus support
861 CONFIG_CMD_IDE * IDE harddisk support
862 CONFIG_CMD_IMI iminfo
863 CONFIG_CMD_IMLS List all images found in NOR flash
864 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
865 CONFIG_CMD_IMMAP * IMMR dump support
866 CONFIG_CMD_IMPORTENV * import an environment
867 CONFIG_CMD_INI * import data from an ini file into the env
868 CONFIG_CMD_IRQ * irqinfo
869 CONFIG_CMD_ITEST Integer/string test of 2 values
870 CONFIG_CMD_JFFS2 * JFFS2 Support
871 CONFIG_CMD_KGDB * kgdb
872 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
873 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
875 CONFIG_CMD_LOADB loadb
876 CONFIG_CMD_LOADS loads
877 CONFIG_CMD_MD5SUM print md5 message digest
878 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
879 CONFIG_CMD_MEMINFO * Display detailed memory information
880 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
882 CONFIG_CMD_MEMTEST mtest
883 CONFIG_CMD_MISC Misc functions like sleep etc
884 CONFIG_CMD_MMC * MMC memory mapped support
885 CONFIG_CMD_MII * MII utility commands
886 CONFIG_CMD_MTDPARTS * MTD partition support
887 CONFIG_CMD_NAND * NAND support
888 CONFIG_CMD_NET bootp, tftpboot, rarpboot
889 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
890 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
891 CONFIG_CMD_PCI * pciinfo
892 CONFIG_CMD_PCMCIA * PCMCIA support
893 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
895 CONFIG_CMD_PORTIO * Port I/O
896 CONFIG_CMD_READ * Read raw data from partition
897 CONFIG_CMD_REGINFO * Register dump
898 CONFIG_CMD_RUN run command in env variable
899 CONFIG_CMD_SANDBOX * sb command to access sandbox features
900 CONFIG_CMD_SAVES * save S record dump
901 CONFIG_CMD_SCSI * SCSI Support
902 CONFIG_CMD_SDRAM * print SDRAM configuration information
903 (requires CONFIG_CMD_I2C)
904 CONFIG_CMD_SETGETDCR Support for DCR Register access
906 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
907 CONFIG_CMD_SHA1SUM print sha1 memory digest
908 (requires CONFIG_CMD_MEMORY)
909 CONFIG_CMD_SOURCE "source" command Support
910 CONFIG_CMD_SPI * SPI serial bus support
911 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
912 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
913 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
914 CONFIG_CMD_TIMER * access to the system tick timer
915 CONFIG_CMD_USB * USB support
916 CONFIG_CMD_CDP * Cisco Discover Protocol support
917 CONFIG_CMD_MFSL * Microblaze FSL support
920 EXAMPLE: If you want all functions except of network
921 support you can write:
923 #include "config_cmd_all.h"
924 #undef CONFIG_CMD_NET
927 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
929 Note: Don't enable the "icache" and "dcache" commands
930 (configuration option CONFIG_CMD_CACHE) unless you know
931 what you (and your U-Boot users) are doing. Data
932 cache cannot be enabled on systems like the 8xx or
933 8260 (where accesses to the IMMR region must be
934 uncached), and it cannot be disabled on all other
935 systems where we (mis-) use the data cache to hold an
936 initial stack and some data.
939 XXX - this list needs to get updated!
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.
1212 CONFIG_GENERIC_LPC_TPM
1213 Support for generic parallel port TPM devices. Only one device
1214 per system is supported at this time.
1216 CONFIG_TPM_TIS_BASE_ADDRESS
1217 Base address where the generic TPM device is mapped
1218 to. Contemporary x86 systems usually map it at
1222 At the moment only the UHCI host controller is
1223 supported (PIP405, MIP405, MPC5200); define
1224 CONFIG_USB_UHCI to enable it.
1225 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1226 and define CONFIG_USB_STORAGE to enable the USB
1229 Supported are USB Keyboards and USB Floppy drives
1231 MPC5200 USB requires additional defines:
1233 for 528 MHz Clock: 0x0001bbbb
1237 for differential drivers: 0x00001000
1238 for single ended drivers: 0x00005000
1239 for differential drivers on PSC3: 0x00000100
1240 for single ended drivers on PSC3: 0x00004100
1241 CONFIG_SYS_USB_EVENT_POLL
1242 May be defined to allow interrupt polling
1243 instead of using asynchronous interrupts
1245 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1246 txfilltuning field in the EHCI controller on reset.
1249 Define the below if you wish to use the USB console.
1250 Once firmware is rebuilt from a serial console issue the
1251 command "setenv stdin usbtty; setenv stdout usbtty" and
1252 attach your USB cable. The Unix command "dmesg" should print
1253 it has found a new device. The environment variable usbtty
1254 can be set to gserial or cdc_acm to enable your device to
1255 appear to a USB host as a Linux gserial device or a
1256 Common Device Class Abstract Control Model serial device.
1257 If you select usbtty = gserial you should be able to enumerate
1259 # modprobe usbserial vendor=0xVendorID product=0xProductID
1260 else if using cdc_acm, simply setting the environment
1261 variable usbtty to be cdc_acm should suffice. The following
1262 might be defined in YourBoardName.h
1265 Define this to build a UDC device
1268 Define this to have a tty type of device available to
1269 talk to the UDC device
1272 Define this to enable the high speed support for usb
1273 device and usbtty. If this feature is enabled, a routine
1274 int is_usbd_high_speed(void)
1275 also needs to be defined by the driver to dynamically poll
1276 whether the enumeration has succeded at high speed or full
1279 CONFIG_SYS_CONSOLE_IS_IN_ENV
1280 Define this if you want stdin, stdout &/or stderr to
1284 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1285 Derive USB clock from external clock "blah"
1286 - CONFIG_SYS_USB_EXTC_CLK 0x02
1288 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1289 Derive USB clock from brgclk
1290 - CONFIG_SYS_USB_BRG_CLK 0x04
1292 If you have a USB-IF assigned VendorID then you may wish to
1293 define your own vendor specific values either in BoardName.h
1294 or directly in usbd_vendor_info.h. If you don't define
1295 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1296 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1297 should pretend to be a Linux device to it's target host.
1299 CONFIG_USBD_MANUFACTURER
1300 Define this string as the name of your company for
1301 - CONFIG_USBD_MANUFACTURER "my company"
1303 CONFIG_USBD_PRODUCT_NAME
1304 Define this string as the name of your product
1305 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1307 CONFIG_USBD_VENDORID
1308 Define this as your assigned Vendor ID from the USB
1309 Implementors Forum. This *must* be a genuine Vendor ID
1310 to avoid polluting the USB namespace.
1311 - CONFIG_USBD_VENDORID 0xFFFF
1313 CONFIG_USBD_PRODUCTID
1314 Define this as the unique Product ID
1316 - CONFIG_USBD_PRODUCTID 0xFFFF
1318 - ULPI Layer Support:
1319 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1320 the generic ULPI layer. The generic layer accesses the ULPI PHY
1321 via the platform viewport, so you need both the genric layer and
1322 the viewport enabled. Currently only Chipidea/ARC based
1323 viewport is supported.
1324 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1325 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1326 If your ULPI phy needs a different reference clock than the
1327 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1328 the appropriate value in Hz.
1331 The MMC controller on the Intel PXA is supported. To
1332 enable this define CONFIG_MMC. The MMC can be
1333 accessed from the boot prompt by mapping the device
1334 to physical memory similar to flash. Command line is
1335 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1336 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1339 Support for Renesas on-chip MMCIF controller
1341 CONFIG_SH_MMCIF_ADDR
1342 Define the base address of MMCIF registers
1345 Define the clock frequency for MMCIF
1347 - USB Device Firmware Update (DFU) class support:
1349 This enables the USB portion of the DFU USB class
1352 This enables the command "dfu" which is used to have
1353 U-Boot create a DFU class device via USB. This command
1354 requires that the "dfu_alt_info" environment variable be
1355 set and define the alt settings to expose to the host.
1358 This enables support for exposing (e)MMC devices via DFU.
1360 CONFIG_SYS_DFU_MAX_FILE_SIZE
1361 When updating files rather than the raw storage device,
1362 we use a static buffer to copy the file into and then write
1363 the buffer once we've been given the whole file. Define
1364 this to the maximum filesize (in bytes) for the buffer.
1365 Default is 4 MiB if undefined.
1367 - Journaling Flash filesystem support:
1368 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1369 CONFIG_JFFS2_NAND_DEV
1370 Define these for a default partition on a NAND device
1372 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1373 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1374 Define these for a default partition on a NOR device
1376 CONFIG_SYS_JFFS_CUSTOM_PART
1377 Define this to create an own partition. You have to provide a
1378 function struct part_info* jffs2_part_info(int part_num)
1380 If you define only one JFFS2 partition you may also want to
1381 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1382 to disable the command chpart. This is the default when you
1383 have not defined a custom partition
1385 - FAT(File Allocation Table) filesystem write function support:
1388 Define this to enable support for saving memory data as a
1389 file in FAT formatted partition.
1391 This will also enable the command "fatwrite" enabling the
1392 user to write files to FAT.
1394 CBFS (Coreboot Filesystem) support
1397 Define this to enable support for reading from a Coreboot
1398 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1404 Define this to enable standard (PC-Style) keyboard
1408 Standard PC keyboard driver with US (is default) and
1409 GERMAN key layout (switch via environment 'keymap=de') support.
1410 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1411 for cfb_console. Supports cursor blinking.
1416 Define this to enable video support (for output to
1419 CONFIG_VIDEO_CT69000
1421 Enable Chips & Technologies 69000 Video chip
1423 CONFIG_VIDEO_SMI_LYNXEM
1424 Enable Silicon Motion SMI 712/710/810 Video chip. The
1425 video output is selected via environment 'videoout'
1426 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1429 For the CT69000 and SMI_LYNXEM drivers, videomode is
1430 selected via environment 'videomode'. Two different ways
1432 - "videomode=num" 'num' is a standard LiLo mode numbers.
1433 Following standard modes are supported (* is default):
1435 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1436 -------------+---------------------------------------------
1437 8 bits | 0x301* 0x303 0x305 0x161 0x307
1438 15 bits | 0x310 0x313 0x316 0x162 0x319
1439 16 bits | 0x311 0x314 0x317 0x163 0x31A
1440 24 bits | 0x312 0x315 0x318 ? 0x31B
1441 -------------+---------------------------------------------
1442 (i.e. setenv videomode 317; saveenv; reset;)
1444 - "videomode=bootargs" all the video parameters are parsed
1445 from the bootargs. (See drivers/video/videomodes.c)
1448 CONFIG_VIDEO_SED13806
1449 Enable Epson SED13806 driver. This driver supports 8bpp
1450 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1451 or CONFIG_VIDEO_SED13806_16BPP
1454 Enable the Freescale DIU video driver. Reference boards for
1455 SOCs that have a DIU should define this macro to enable DIU
1456 support, and should also define these other macros:
1462 CONFIG_VIDEO_SW_CURSOR
1463 CONFIG_VGA_AS_SINGLE_DEVICE
1465 CONFIG_VIDEO_BMP_LOGO
1467 The DIU driver will look for the 'video-mode' environment
1468 variable, and if defined, enable the DIU as a console during
1469 boot. See the documentation file README.video for a
1470 description of this variable.
1474 Enable the VGA video / BIOS for x86. The alternative if you
1475 are using coreboot is to use the coreboot frame buffer
1482 Define this to enable a custom keyboard support.
1483 This simply calls drv_keyboard_init() which must be
1484 defined in your board-specific files.
1485 The only board using this so far is RBC823.
1487 - LCD Support: CONFIG_LCD
1489 Define this to enable LCD support (for output to LCD
1490 display); also select one of the supported displays
1491 by defining one of these:
1495 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1497 CONFIG_NEC_NL6448AC33:
1499 NEC NL6448AC33-18. Active, color, single scan.
1501 CONFIG_NEC_NL6448BC20
1503 NEC NL6448BC20-08. 6.5", 640x480.
1504 Active, color, single scan.
1506 CONFIG_NEC_NL6448BC33_54
1508 NEC NL6448BC33-54. 10.4", 640x480.
1509 Active, color, single scan.
1513 Sharp 320x240. Active, color, single scan.
1514 It isn't 16x9, and I am not sure what it is.
1516 CONFIG_SHARP_LQ64D341
1518 Sharp LQ64D341 display, 640x480.
1519 Active, color, single scan.
1523 HLD1045 display, 640x480.
1524 Active, color, single scan.
1528 Optrex CBL50840-2 NF-FW 99 22 M5
1530 Hitachi LMG6912RPFC-00T
1534 320x240. Black & white.
1536 Normally display is black on white background; define
1537 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1539 CONFIG_LCD_ALIGNMENT
1541 Normally the LCD is page-aligned (tyically 4KB). If this is
1542 defined then the LCD will be aligned to this value instead.
1543 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1544 here, since it is cheaper to change data cache settings on
1545 a per-section basis.
1547 CONFIG_CONSOLE_SCROLL_LINES
1549 When the console need to be scrolled, this is the number of
1550 lines to scroll by. It defaults to 1. Increasing this makes
1551 the console jump but can help speed up operation when scrolling
1556 Support drawing of RLE8-compressed bitmaps on the LCD.
1560 Enables an 'i2c edid' command which can read EDID
1561 information over I2C from an attached LCD display.
1563 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1565 If this option is set, the environment is checked for
1566 a variable "splashimage". If found, the usual display
1567 of logo, copyright and system information on the LCD
1568 is suppressed and the BMP image at the address
1569 specified in "splashimage" is loaded instead. The
1570 console is redirected to the "nulldev", too. This
1571 allows for a "silent" boot where a splash screen is
1572 loaded very quickly after power-on.
1574 CONFIG_SPLASHIMAGE_GUARD
1576 If this option is set, then U-Boot will prevent the environment
1577 variable "splashimage" from being set to a problematic address
1578 (see README.displaying-bmps and README.arm-unaligned-accesses).
1579 This option is useful for targets where, due to alignment
1580 restrictions, an improperly aligned BMP image will cause a data
1581 abort. If you think you will not have problems with unaligned
1582 accesses (for example because your toolchain prevents them)
1583 there is no need to set this option.
1585 CONFIG_SPLASH_SCREEN_ALIGN
1587 If this option is set the splash image can be freely positioned
1588 on the screen. Environment variable "splashpos" specifies the
1589 position as "x,y". If a positive number is given it is used as
1590 number of pixel from left/top. If a negative number is given it
1591 is used as number of pixel from right/bottom. You can also
1592 specify 'm' for centering the image.
1595 setenv splashpos m,m
1596 => image at center of screen
1598 setenv splashpos 30,20
1599 => image at x = 30 and y = 20
1601 setenv splashpos -10,m
1602 => vertically centered image
1603 at x = dspWidth - bmpWidth - 9
1605 CONFIG_SPLASH_SCREEN_PREPARE
1607 If this option is set then the board_splash_screen_prepare()
1608 function, which must be defined in your code, is called as part
1609 of the splash screen display sequence. It gives the board an
1610 opportunity to prepare the splash image data before it is
1611 processed and sent to the frame buffer by U-Boot.
1613 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1615 If this option is set, additionally to standard BMP
1616 images, gzipped BMP images can be displayed via the
1617 splashscreen support or the bmp command.
1619 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1621 If this option is set, 8-bit RLE compressed BMP images
1622 can be displayed via the splashscreen support or the
1625 - Do compresssing for memory range:
1628 If this option is set, it would use zlib deflate method
1629 to compress the specified memory at its best effort.
1631 - Compression support:
1634 If this option is set, support for bzip2 compressed
1635 images is included. If not, only uncompressed and gzip
1636 compressed images are supported.
1638 NOTE: the bzip2 algorithm requires a lot of RAM, so
1639 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1644 If this option is set, support for lzma compressed
1647 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1648 requires an amount of dynamic memory that is given by the
1651 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1653 Where lc and lp stand for, respectively, Literal context bits
1654 and Literal pos bits.
1656 This value is upper-bounded by 14MB in the worst case. Anyway,
1657 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1658 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1659 a very small buffer.
1661 Use the lzmainfo tool to determinate the lc and lp values and
1662 then calculate the amount of needed dynamic memory (ensuring
1663 the appropriate CONFIG_SYS_MALLOC_LEN value).
1668 The address of PHY on MII bus.
1670 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1672 The clock frequency of the MII bus
1676 If this option is set, support for speed/duplex
1677 detection of gigabit PHY is included.
1679 CONFIG_PHY_RESET_DELAY
1681 Some PHY like Intel LXT971A need extra delay after
1682 reset before any MII register access is possible.
1683 For such PHY, set this option to the usec delay
1684 required. (minimum 300usec for LXT971A)
1686 CONFIG_PHY_CMD_DELAY (ppc4xx)
1688 Some PHY like Intel LXT971A need extra delay after
1689 command issued before MII status register can be read
1699 Define a default value for Ethernet address to use
1700 for the respective Ethernet interface, in case this
1701 is not determined automatically.
1706 Define a default value for the IP address to use for
1707 the default Ethernet interface, in case this is not
1708 determined through e.g. bootp.
1709 (Environment variable "ipaddr")
1711 - Server IP address:
1714 Defines a default value for the IP address of a TFTP
1715 server to contact when using the "tftboot" command.
1716 (Environment variable "serverip")
1718 CONFIG_KEEP_SERVERADDR
1720 Keeps the server's MAC address, in the env 'serveraddr'
1721 for passing to bootargs (like Linux's netconsole option)
1723 - Gateway IP address:
1726 Defines a default value for the IP address of the
1727 default router where packets to other networks are
1729 (Environment variable "gatewayip")
1734 Defines a default value for the subnet mask (or
1735 routing prefix) which is used to determine if an IP
1736 address belongs to the local subnet or needs to be
1737 forwarded through a router.
1738 (Environment variable "netmask")
1740 - Multicast TFTP Mode:
1743 Defines whether you want to support multicast TFTP as per
1744 rfc-2090; for example to work with atftp. Lets lots of targets
1745 tftp down the same boot image concurrently. Note: the Ethernet
1746 driver in use must provide a function: mcast() to join/leave a
1749 - BOOTP Recovery Mode:
1750 CONFIG_BOOTP_RANDOM_DELAY
1752 If you have many targets in a network that try to
1753 boot using BOOTP, you may want to avoid that all
1754 systems send out BOOTP requests at precisely the same
1755 moment (which would happen for instance at recovery
1756 from a power failure, when all systems will try to
1757 boot, thus flooding the BOOTP server. Defining
1758 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1759 inserted before sending out BOOTP requests. The
1760 following delays are inserted then:
1762 1st BOOTP request: delay 0 ... 1 sec
1763 2nd BOOTP request: delay 0 ... 2 sec
1764 3rd BOOTP request: delay 0 ... 4 sec
1766 BOOTP requests: delay 0 ... 8 sec
1768 - DHCP Advanced Options:
1769 You can fine tune the DHCP functionality by defining
1770 CONFIG_BOOTP_* symbols:
1772 CONFIG_BOOTP_SUBNETMASK
1773 CONFIG_BOOTP_GATEWAY
1774 CONFIG_BOOTP_HOSTNAME
1775 CONFIG_BOOTP_NISDOMAIN
1776 CONFIG_BOOTP_BOOTPATH
1777 CONFIG_BOOTP_BOOTFILESIZE
1780 CONFIG_BOOTP_SEND_HOSTNAME
1781 CONFIG_BOOTP_NTPSERVER
1782 CONFIG_BOOTP_TIMEOFFSET
1783 CONFIG_BOOTP_VENDOREX
1784 CONFIG_BOOTP_MAY_FAIL
1786 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1787 environment variable, not the BOOTP server.
1789 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1790 after the configured retry count, the call will fail
1791 instead of starting over. This can be used to fail over
1792 to Link-local IP address configuration if the DHCP server
1795 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1796 serverip from a DHCP server, it is possible that more
1797 than one DNS serverip is offered to the client.
1798 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1799 serverip will be stored in the additional environment
1800 variable "dnsip2". The first DNS serverip is always
1801 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1804 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1805 to do a dynamic update of a DNS server. To do this, they
1806 need the hostname of the DHCP requester.
1807 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1808 of the "hostname" environment variable is passed as
1809 option 12 to the DHCP server.
1811 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1813 A 32bit value in microseconds for a delay between
1814 receiving a "DHCP Offer" and sending the "DHCP Request".
1815 This fixes a problem with certain DHCP servers that don't
1816 respond 100% of the time to a "DHCP request". E.g. On an
1817 AT91RM9200 processor running at 180MHz, this delay needed
1818 to be *at least* 15,000 usec before a Windows Server 2003
1819 DHCP server would reply 100% of the time. I recommend at
1820 least 50,000 usec to be safe. The alternative is to hope
1821 that one of the retries will be successful but note that
1822 the DHCP timeout and retry process takes a longer than
1825 - Link-local IP address negotiation:
1826 Negotiate with other link-local clients on the local network
1827 for an address that doesn't require explicit configuration.
1828 This is especially useful if a DHCP server cannot be guaranteed
1829 to exist in all environments that the device must operate.
1831 See doc/README.link-local for more information.
1834 CONFIG_CDP_DEVICE_ID
1836 The device id used in CDP trigger frames.
1838 CONFIG_CDP_DEVICE_ID_PREFIX
1840 A two character string which is prefixed to the MAC address
1845 A printf format string which contains the ascii name of
1846 the port. Normally is set to "eth%d" which sets
1847 eth0 for the first Ethernet, eth1 for the second etc.
1849 CONFIG_CDP_CAPABILITIES
1851 A 32bit integer which indicates the device capabilities;
1852 0x00000010 for a normal host which does not forwards.
1856 An ascii string containing the version of the software.
1860 An ascii string containing the name of the platform.
1864 A 32bit integer sent on the trigger.
1866 CONFIG_CDP_POWER_CONSUMPTION
1868 A 16bit integer containing the power consumption of the
1869 device in .1 of milliwatts.
1871 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1873 A byte containing the id of the VLAN.
1875 - Status LED: CONFIG_STATUS_LED
1877 Several configurations allow to display the current
1878 status using a LED. For instance, the LED will blink
1879 fast while running U-Boot code, stop blinking as
1880 soon as a reply to a BOOTP request was received, and
1881 start blinking slow once the Linux kernel is running
1882 (supported by a status LED driver in the Linux
1883 kernel). Defining CONFIG_STATUS_LED enables this
1886 - CAN Support: CONFIG_CAN_DRIVER
1888 Defining CONFIG_CAN_DRIVER enables CAN driver support
1889 on those systems that support this (optional)
1890 feature, like the TQM8xxL modules.
1892 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1894 These enable I2C serial bus commands. Defining either of
1895 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1896 include the appropriate I2C driver for the selected CPU.
1898 This will allow you to use i2c commands at the u-boot
1899 command line (as long as you set CONFIG_CMD_I2C in
1900 CONFIG_COMMANDS) and communicate with i2c based realtime
1901 clock chips. See common/cmd_i2c.c for a description of the
1902 command line interface.
1904 CONFIG_HARD_I2C selects a hardware I2C controller.
1906 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1907 bit-banging) driver instead of CPM or similar hardware
1910 There are several other quantities that must also be
1911 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1913 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1914 to be the frequency (in Hz) at which you wish your i2c bus
1915 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1916 the CPU's i2c node address).
1918 Now, the u-boot i2c code for the mpc8xx
1919 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1920 and so its address should therefore be cleared to 0 (See,
1921 eg, MPC823e User's Manual p.16-473). So, set
1922 CONFIG_SYS_I2C_SLAVE to 0.
1924 CONFIG_SYS_I2C_INIT_MPC5XXX
1926 When a board is reset during an i2c bus transfer
1927 chips might think that the current transfer is still
1928 in progress. Reset the slave devices by sending start
1929 commands until the slave device responds.
1931 That's all that's required for CONFIG_HARD_I2C.
1933 If you use the software i2c interface (CONFIG_SOFT_I2C)
1934 then the following macros need to be defined (examples are
1935 from include/configs/lwmon.h):
1939 (Optional). Any commands necessary to enable the I2C
1940 controller or configure ports.
1942 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1946 (Only for MPC8260 CPU). The I/O port to use (the code
1947 assumes both bits are on the same port). Valid values
1948 are 0..3 for ports A..D.
1952 The code necessary to make the I2C data line active
1953 (driven). If the data line is open collector, this
1956 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1960 The code necessary to make the I2C data line tri-stated
1961 (inactive). If the data line is open collector, this
1964 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1968 Code that returns true if the I2C data line is high,
1971 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1975 If <bit> is true, sets the I2C data line high. If it
1976 is false, it clears it (low).
1978 eg: #define I2C_SDA(bit) \
1979 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1980 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1984 If <bit> is true, sets the I2C clock line high. If it
1985 is false, it clears it (low).
1987 eg: #define I2C_SCL(bit) \
1988 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1989 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1993 This delay is invoked four times per clock cycle so this
1994 controls the rate of data transfer. The data rate thus
1995 is 1 / (I2C_DELAY * 4). Often defined to be something
1998 #define I2C_DELAY udelay(2)
2000 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2002 If your arch supports the generic GPIO framework (asm/gpio.h),
2003 then you may alternatively define the two GPIOs that are to be
2004 used as SCL / SDA. Any of the previous I2C_xxx macros will
2005 have GPIO-based defaults assigned to them as appropriate.
2007 You should define these to the GPIO value as given directly to
2008 the generic GPIO functions.
2010 CONFIG_SYS_I2C_INIT_BOARD
2012 When a board is reset during an i2c bus transfer
2013 chips might think that the current transfer is still
2014 in progress. On some boards it is possible to access
2015 the i2c SCLK line directly, either by using the
2016 processor pin as a GPIO or by having a second pin
2017 connected to the bus. If this option is defined a
2018 custom i2c_init_board() routine in boards/xxx/board.c
2019 is run early in the boot sequence.
2021 CONFIG_SYS_I2C_BOARD_LATE_INIT
2023 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2024 defined a custom i2c_board_late_init() routine in
2025 boards/xxx/board.c is run AFTER the operations in i2c_init()
2026 is completed. This callpoint can be used to unreset i2c bus
2027 using CPU i2c controller register accesses for CPUs whose i2c
2028 controller provide such a method. It is called at the end of
2029 i2c_init() to allow i2c_init operations to setup the i2c bus
2030 controller on the CPU (e.g. setting bus speed & slave address).
2032 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2034 This option enables configuration of bi_iic_fast[] flags
2035 in u-boot bd_info structure based on u-boot environment
2036 variable "i2cfast". (see also i2cfast)
2038 CONFIG_I2C_MULTI_BUS
2040 This option allows the use of multiple I2C buses, each of which
2041 must have a controller. At any point in time, only one bus is
2042 active. To switch to a different bus, use the 'i2c dev' command.
2043 Note that bus numbering is zero-based.
2045 CONFIG_SYS_I2C_NOPROBES
2047 This option specifies a list of I2C devices that will be skipped
2048 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2049 is set, specify a list of bus-device pairs. Otherwise, specify
2050 a 1D array of device addresses
2053 #undef CONFIG_I2C_MULTI_BUS
2054 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2056 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2058 #define CONFIG_I2C_MULTI_BUS
2059 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2061 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2063 CONFIG_SYS_SPD_BUS_NUM
2065 If defined, then this indicates the I2C bus number for DDR SPD.
2066 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2068 CONFIG_SYS_RTC_BUS_NUM
2070 If defined, then this indicates the I2C bus number for the RTC.
2071 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2073 CONFIG_SYS_DTT_BUS_NUM
2075 If defined, then this indicates the I2C bus number for the DTT.
2076 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2078 CONFIG_SYS_I2C_DTT_ADDR:
2080 If defined, specifies the I2C address of the DTT device.
2081 If not defined, then U-Boot uses predefined value for
2082 specified DTT device.
2086 Define this option if you want to use Freescale's I2C driver in
2087 drivers/i2c/fsl_i2c.c.
2091 Define this option if you have I2C devices reached over 1 .. n
2092 I2C Muxes like the pca9544a. This option addes a new I2C
2093 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2094 new I2C Bus to the existing I2C Busses. If you select the
2095 new Bus with "i2c dev", u-bbot sends first the commandos for
2096 the muxes to activate this new "bus".
2098 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2102 Adding a new I2C Bus reached over 2 pca9544a muxes
2103 The First mux with address 70 and channel 6
2104 The Second mux with address 71 and channel 4
2106 => i2c bus pca9544a:70:6:pca9544a:71:4
2108 Use the "i2c bus" command without parameter, to get a list
2109 of I2C Busses with muxes:
2112 Busses reached over muxes:
2114 reached over Mux(es):
2117 reached over Mux(es):
2122 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2123 u-boot first sends the command to the mux@70 to enable
2124 channel 6, and then the command to the mux@71 to enable
2127 After that, you can use the "normal" i2c commands as
2128 usual to communicate with your I2C devices behind
2131 This option is actually implemented for the bitbanging
2132 algorithm in common/soft_i2c.c and for the Hardware I2C
2133 Bus on the MPC8260. But it should be not so difficult
2134 to add this option to other architectures.
2136 CONFIG_SOFT_I2C_READ_REPEATED_START
2138 defining this will force the i2c_read() function in
2139 the soft_i2c driver to perform an I2C repeated start
2140 between writing the address pointer and reading the
2141 data. If this define is omitted the default behaviour
2142 of doing a stop-start sequence will be used. Most I2C
2143 devices can use either method, but some require one or
2146 - SPI Support: CONFIG_SPI
2148 Enables SPI driver (so far only tested with
2149 SPI EEPROM, also an instance works with Crystal A/D and
2150 D/As on the SACSng board)
2154 Enables the driver for SPI controller on SuperH. Currently
2155 only SH7757 is supported.
2159 Enables extended (16-bit) SPI EEPROM addressing.
2160 (symmetrical to CONFIG_I2C_X)
2164 Enables a software (bit-bang) SPI driver rather than
2165 using hardware support. This is a general purpose
2166 driver that only requires three general I/O port pins
2167 (two outputs, one input) to function. If this is
2168 defined, the board configuration must define several
2169 SPI configuration items (port pins to use, etc). For
2170 an example, see include/configs/sacsng.h.
2174 Enables a hardware SPI driver for general-purpose reads
2175 and writes. As with CONFIG_SOFT_SPI, the board configuration
2176 must define a list of chip-select function pointers.
2177 Currently supported on some MPC8xxx processors. For an
2178 example, see include/configs/mpc8349emds.h.
2182 Enables the driver for the SPI controllers on i.MX and MXC
2183 SoCs. Currently i.MX31/35/51 are supported.
2185 - FPGA Support: CONFIG_FPGA
2187 Enables FPGA subsystem.
2189 CONFIG_FPGA_<vendor>
2191 Enables support for specific chip vendors.
2194 CONFIG_FPGA_<family>
2196 Enables support for FPGA family.
2197 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2201 Specify the number of FPGA devices to support.
2203 CONFIG_SYS_FPGA_PROG_FEEDBACK
2205 Enable printing of hash marks during FPGA configuration.
2207 CONFIG_SYS_FPGA_CHECK_BUSY
2209 Enable checks on FPGA configuration interface busy
2210 status by the configuration function. This option
2211 will require a board or device specific function to
2216 If defined, a function that provides delays in the FPGA
2217 configuration driver.
2219 CONFIG_SYS_FPGA_CHECK_CTRLC
2220 Allow Control-C to interrupt FPGA configuration
2222 CONFIG_SYS_FPGA_CHECK_ERROR
2224 Check for configuration errors during FPGA bitfile
2225 loading. For example, abort during Virtex II
2226 configuration if the INIT_B line goes low (which
2227 indicated a CRC error).
2229 CONFIG_SYS_FPGA_WAIT_INIT
2231 Maximum time to wait for the INIT_B line to deassert
2232 after PROB_B has been deasserted during a Virtex II
2233 FPGA configuration sequence. The default time is 500
2236 CONFIG_SYS_FPGA_WAIT_BUSY
2238 Maximum time to wait for BUSY to deassert during
2239 Virtex II FPGA configuration. The default is 5 ms.
2241 CONFIG_SYS_FPGA_WAIT_CONFIG
2243 Time to wait after FPGA configuration. The default is
2246 - Configuration Management:
2249 If defined, this string will be added to the U-Boot
2250 version information (U_BOOT_VERSION)
2252 - Vendor Parameter Protection:
2254 U-Boot considers the values of the environment
2255 variables "serial#" (Board Serial Number) and
2256 "ethaddr" (Ethernet Address) to be parameters that
2257 are set once by the board vendor / manufacturer, and
2258 protects these variables from casual modification by
2259 the user. Once set, these variables are read-only,
2260 and write or delete attempts are rejected. You can
2261 change this behaviour:
2263 If CONFIG_ENV_OVERWRITE is #defined in your config
2264 file, the write protection for vendor parameters is
2265 completely disabled. Anybody can change or delete
2268 Alternatively, if you #define _both_ CONFIG_ETHADDR
2269 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2270 Ethernet address is installed in the environment,
2271 which can be changed exactly ONCE by the user. [The
2272 serial# is unaffected by this, i. e. it remains
2275 The same can be accomplished in a more flexible way
2276 for any variable by configuring the type of access
2277 to allow for those variables in the ".flags" variable
2278 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2283 Define this variable to enable the reservation of
2284 "protected RAM", i. e. RAM which is not overwritten
2285 by U-Boot. Define CONFIG_PRAM to hold the number of
2286 kB you want to reserve for pRAM. You can overwrite
2287 this default value by defining an environment
2288 variable "pram" to the number of kB you want to
2289 reserve. Note that the board info structure will
2290 still show the full amount of RAM. If pRAM is
2291 reserved, a new environment variable "mem" will
2292 automatically be defined to hold the amount of
2293 remaining RAM in a form that can be passed as boot
2294 argument to Linux, for instance like that:
2296 setenv bootargs ... mem=\${mem}
2299 This way you can tell Linux not to use this memory,
2300 either, which results in a memory region that will
2301 not be affected by reboots.
2303 *WARNING* If your board configuration uses automatic
2304 detection of the RAM size, you must make sure that
2305 this memory test is non-destructive. So far, the
2306 following board configurations are known to be
2309 IVMS8, IVML24, SPD8xx, TQM8xxL,
2310 HERMES, IP860, RPXlite, LWMON,
2313 - Access to physical memory region (> 4GB)
2314 Some basic support is provided for operations on memory not
2315 normally accessible to U-Boot - e.g. some architectures
2316 support access to more than 4GB of memory on 32-bit
2317 machines using physical address extension or similar.
2318 Define CONFIG_PHYSMEM to access this basic support, which
2319 currently only supports clearing the memory.
2324 Define this variable to stop the system in case of a
2325 fatal error, so that you have to reset it manually.
2326 This is probably NOT a good idea for an embedded
2327 system where you want the system to reboot
2328 automatically as fast as possible, but it may be
2329 useful during development since you can try to debug
2330 the conditions that lead to the situation.
2332 CONFIG_NET_RETRY_COUNT
2334 This variable defines the number of retries for
2335 network operations like ARP, RARP, TFTP, or BOOTP
2336 before giving up the operation. If not defined, a
2337 default value of 5 is used.
2341 Timeout waiting for an ARP reply in milliseconds.
2345 Timeout in milliseconds used in NFS protocol.
2346 If you encounter "ERROR: Cannot umount" in nfs command,
2347 try longer timeout such as
2348 #define CONFIG_NFS_TIMEOUT 10000UL
2350 - Command Interpreter:
2351 CONFIG_AUTO_COMPLETE
2353 Enable auto completion of commands using TAB.
2355 Note that this feature has NOT been implemented yet
2356 for the "hush" shell.
2359 CONFIG_SYS_HUSH_PARSER
2361 Define this variable to enable the "hush" shell (from
2362 Busybox) as command line interpreter, thus enabling
2363 powerful command line syntax like
2364 if...then...else...fi conditionals or `&&' and '||'
2365 constructs ("shell scripts").
2367 If undefined, you get the old, much simpler behaviour
2368 with a somewhat smaller memory footprint.
2371 CONFIG_SYS_PROMPT_HUSH_PS2
2373 This defines the secondary prompt string, which is
2374 printed when the command interpreter needs more input
2375 to complete a command. Usually "> ".
2379 In the current implementation, the local variables
2380 space and global environment variables space are
2381 separated. Local variables are those you define by
2382 simply typing `name=value'. To access a local
2383 variable later on, you have write `$name' or
2384 `${name}'; to execute the contents of a variable
2385 directly type `$name' at the command prompt.
2387 Global environment variables are those you use
2388 setenv/printenv to work with. To run a command stored
2389 in such a variable, you need to use the run command,
2390 and you must not use the '$' sign to access them.
2392 To store commands and special characters in a
2393 variable, please use double quotation marks
2394 surrounding the whole text of the variable, instead
2395 of the backslashes before semicolons and special
2398 - Commandline Editing and History:
2399 CONFIG_CMDLINE_EDITING
2401 Enable editing and History functions for interactive
2402 commandline input operations
2404 - Default Environment:
2405 CONFIG_EXTRA_ENV_SETTINGS
2407 Define this to contain any number of null terminated
2408 strings (variable = value pairs) that will be part of
2409 the default environment compiled into the boot image.
2411 For example, place something like this in your
2412 board's config file:
2414 #define CONFIG_EXTRA_ENV_SETTINGS \
2418 Warning: This method is based on knowledge about the
2419 internal format how the environment is stored by the
2420 U-Boot code. This is NOT an official, exported
2421 interface! Although it is unlikely that this format
2422 will change soon, there is no guarantee either.
2423 You better know what you are doing here.
2425 Note: overly (ab)use of the default environment is
2426 discouraged. Make sure to check other ways to preset
2427 the environment like the "source" command or the
2430 CONFIG_ENV_VARS_UBOOT_CONFIG
2432 Define this in order to add variables describing the
2433 U-Boot build configuration to the default environment.
2434 These will be named arch, cpu, board, vendor, and soc.
2436 Enabling this option will cause the following to be defined:
2444 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2446 Define this in order to add variables describing certain
2447 run-time determined information about the hardware to the
2448 environment. These will be named board_name, board_rev.
2450 CONFIG_DELAY_ENVIRONMENT
2452 Normally the environment is loaded when the board is
2453 intialised so that it is available to U-Boot. This inhibits
2454 that so that the environment is not available until
2455 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2456 this is instead controlled by the value of
2457 /config/load-environment.
2459 - DataFlash Support:
2460 CONFIG_HAS_DATAFLASH
2462 Defining this option enables DataFlash features and
2463 allows to read/write in Dataflash via the standard
2466 - Serial Flash support
2469 Defining this option enables SPI flash commands
2470 'sf probe/read/write/erase/update'.
2472 Usage requires an initial 'probe' to define the serial
2473 flash parameters, followed by read/write/erase/update
2476 The following defaults may be provided by the platform
2477 to handle the common case when only a single serial
2478 flash is present on the system.
2480 CONFIG_SF_DEFAULT_BUS Bus identifier
2481 CONFIG_SF_DEFAULT_CS Chip-select
2482 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2483 CONFIG_SF_DEFAULT_SPEED in Hz
2487 Define this option to include a destructive SPI flash
2490 - SystemACE Support:
2493 Adding this option adds support for Xilinx SystemACE
2494 chips attached via some sort of local bus. The address
2495 of the chip must also be defined in the
2496 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2498 #define CONFIG_SYSTEMACE
2499 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2501 When SystemACE support is added, the "ace" device type
2502 becomes available to the fat commands, i.e. fatls.
2504 - TFTP Fixed UDP Port:
2507 If this is defined, the environment variable tftpsrcp
2508 is used to supply the TFTP UDP source port value.
2509 If tftpsrcp isn't defined, the normal pseudo-random port
2510 number generator is used.
2512 Also, the environment variable tftpdstp is used to supply
2513 the TFTP UDP destination port value. If tftpdstp isn't
2514 defined, the normal port 69 is used.
2516 The purpose for tftpsrcp is to allow a TFTP server to
2517 blindly start the TFTP transfer using the pre-configured
2518 target IP address and UDP port. This has the effect of
2519 "punching through" the (Windows XP) firewall, allowing
2520 the remainder of the TFTP transfer to proceed normally.
2521 A better solution is to properly configure the firewall,
2522 but sometimes that is not allowed.
2527 This enables a generic 'hash' command which can produce
2528 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2532 Enable the hash verify command (hash -v). This adds to code
2535 CONFIG_SHA1 - support SHA1 hashing
2536 CONFIG_SHA256 - support SHA256 hashing
2538 Note: There is also a sha1sum command, which should perhaps
2539 be deprecated in favour of 'hash sha1'.
2541 - Show boot progress:
2542 CONFIG_SHOW_BOOT_PROGRESS
2544 Defining this option allows to add some board-
2545 specific code (calling a user-provided function
2546 "show_boot_progress(int)") that enables you to show
2547 the system's boot progress on some display (for
2548 example, some LED's) on your board. At the moment,
2549 the following checkpoints are implemented:
2551 - Detailed boot stage timing
2553 Define this option to get detailed timing of each stage
2554 of the boot process.
2556 CONFIG_BOOTSTAGE_USER_COUNT
2557 This is the number of available user bootstage records.
2558 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2559 a new ID will be allocated from this stash. If you exceed
2560 the limit, recording will stop.
2562 CONFIG_BOOTSTAGE_REPORT
2563 Define this to print a report before boot, similar to this:
2565 Timer summary in microseconds:
2568 3,575,678 3,575,678 board_init_f start
2569 3,575,695 17 arch_cpu_init A9
2570 3,575,777 82 arch_cpu_init done
2571 3,659,598 83,821 board_init_r start
2572 3,910,375 250,777 main_loop
2573 29,916,167 26,005,792 bootm_start
2574 30,361,327 445,160 start_kernel
2576 CONFIG_CMD_BOOTSTAGE
2577 Add a 'bootstage' command which supports printing a report
2578 and un/stashing of bootstage data.
2580 CONFIG_BOOTSTAGE_FDT
2581 Stash the bootstage information in the FDT. A root 'bootstage'
2582 node is created with each bootstage id as a child. Each child
2583 has a 'name' property and either 'mark' containing the
2584 mark time in microsecond, or 'accum' containing the
2585 accumulated time for that bootstage id in microseconds.
2590 name = "board_init_f";
2599 Code in the Linux kernel can find this in /proc/devicetree.
2601 Legacy uImage format:
2604 1 common/cmd_bootm.c before attempting to boot an image
2605 -1 common/cmd_bootm.c Image header has bad magic number
2606 2 common/cmd_bootm.c Image header has correct magic number
2607 -2 common/cmd_bootm.c Image header has bad checksum
2608 3 common/cmd_bootm.c Image header has correct checksum
2609 -3 common/cmd_bootm.c Image data has bad checksum
2610 4 common/cmd_bootm.c Image data has correct checksum
2611 -4 common/cmd_bootm.c Image is for unsupported architecture
2612 5 common/cmd_bootm.c Architecture check OK
2613 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2614 6 common/cmd_bootm.c Image Type check OK
2615 -6 common/cmd_bootm.c gunzip uncompression error
2616 -7 common/cmd_bootm.c Unimplemented compression type
2617 7 common/cmd_bootm.c Uncompression OK
2618 8 common/cmd_bootm.c No uncompress/copy overwrite error
2619 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2621 9 common/image.c Start initial ramdisk verification
2622 -10 common/image.c Ramdisk header has bad magic number
2623 -11 common/image.c Ramdisk header has bad checksum
2624 10 common/image.c Ramdisk header is OK
2625 -12 common/image.c Ramdisk data has bad checksum
2626 11 common/image.c Ramdisk data has correct checksum
2627 12 common/image.c Ramdisk verification complete, start loading
2628 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2629 13 common/image.c Start multifile image verification
2630 14 common/image.c No initial ramdisk, no multifile, continue.
2632 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2634 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2635 -31 post/post.c POST test failed, detected by post_output_backlog()
2636 -32 post/post.c POST test failed, detected by post_run_single()
2638 34 common/cmd_doc.c before loading a Image from a DOC device
2639 -35 common/cmd_doc.c Bad usage of "doc" command
2640 35 common/cmd_doc.c correct usage of "doc" command
2641 -36 common/cmd_doc.c No boot device
2642 36 common/cmd_doc.c correct boot device
2643 -37 common/cmd_doc.c Unknown Chip ID on boot device
2644 37 common/cmd_doc.c correct chip ID found, device available
2645 -38 common/cmd_doc.c Read Error on boot device
2646 38 common/cmd_doc.c reading Image header from DOC device OK
2647 -39 common/cmd_doc.c Image header has bad magic number
2648 39 common/cmd_doc.c Image header has correct magic number
2649 -40 common/cmd_doc.c Error reading Image from DOC device
2650 40 common/cmd_doc.c Image header has correct magic number
2651 41 common/cmd_ide.c before loading a Image from a IDE device
2652 -42 common/cmd_ide.c Bad usage of "ide" command
2653 42 common/cmd_ide.c correct usage of "ide" command
2654 -43 common/cmd_ide.c No boot device
2655 43 common/cmd_ide.c boot device found
2656 -44 common/cmd_ide.c Device not available
2657 44 common/cmd_ide.c Device available
2658 -45 common/cmd_ide.c wrong partition selected
2659 45 common/cmd_ide.c partition selected
2660 -46 common/cmd_ide.c Unknown partition table
2661 46 common/cmd_ide.c valid partition table found
2662 -47 common/cmd_ide.c Invalid partition type
2663 47 common/cmd_ide.c correct partition type
2664 -48 common/cmd_ide.c Error reading Image Header on boot device
2665 48 common/cmd_ide.c reading Image Header from IDE device OK
2666 -49 common/cmd_ide.c Image header has bad magic number
2667 49 common/cmd_ide.c Image header has correct magic number
2668 -50 common/cmd_ide.c Image header has bad checksum
2669 50 common/cmd_ide.c Image header has correct checksum
2670 -51 common/cmd_ide.c Error reading Image from IDE device
2671 51 common/cmd_ide.c reading Image from IDE device OK
2672 52 common/cmd_nand.c before loading a Image from a NAND device
2673 -53 common/cmd_nand.c Bad usage of "nand" command
2674 53 common/cmd_nand.c correct usage of "nand" command
2675 -54 common/cmd_nand.c No boot device
2676 54 common/cmd_nand.c boot device found
2677 -55 common/cmd_nand.c Unknown Chip ID on boot device
2678 55 common/cmd_nand.c correct chip ID found, device available
2679 -56 common/cmd_nand.c Error reading Image Header on boot device
2680 56 common/cmd_nand.c reading Image Header from NAND device OK
2681 -57 common/cmd_nand.c Image header has bad magic number
2682 57 common/cmd_nand.c Image header has correct magic number
2683 -58 common/cmd_nand.c Error reading Image from NAND device
2684 58 common/cmd_nand.c reading Image from NAND device OK
2686 -60 common/env_common.c Environment has a bad CRC, using default
2688 64 net/eth.c starting with Ethernet configuration.
2689 -64 net/eth.c no Ethernet found.
2690 65 net/eth.c Ethernet found.
2692 -80 common/cmd_net.c usage wrong
2693 80 common/cmd_net.c before calling NetLoop()
2694 -81 common/cmd_net.c some error in NetLoop() occurred
2695 81 common/cmd_net.c NetLoop() back without error
2696 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2697 82 common/cmd_net.c trying automatic boot
2698 83 common/cmd_net.c running "source" command
2699 -83 common/cmd_net.c some error in automatic boot or "source" command
2700 84 common/cmd_net.c end without errors
2705 100 common/cmd_bootm.c Kernel FIT Image has correct format
2706 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2707 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2708 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2709 102 common/cmd_bootm.c Kernel unit name specified
2710 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2711 103 common/cmd_bootm.c Found configuration node
2712 104 common/cmd_bootm.c Got kernel subimage node offset
2713 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2714 105 common/cmd_bootm.c Kernel subimage hash verification OK
2715 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2716 106 common/cmd_bootm.c Architecture check OK
2717 -106 common/cmd_bootm.c Kernel subimage has wrong type
2718 107 common/cmd_bootm.c Kernel subimage type OK
2719 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2720 108 common/cmd_bootm.c Got kernel subimage data/size
2721 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2722 -109 common/cmd_bootm.c Can't get kernel subimage type
2723 -110 common/cmd_bootm.c Can't get kernel subimage comp
2724 -111 common/cmd_bootm.c Can't get kernel subimage os
2725 -112 common/cmd_bootm.c Can't get kernel subimage load address
2726 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2728 120 common/image.c Start initial ramdisk verification
2729 -120 common/image.c Ramdisk FIT image has incorrect format
2730 121 common/image.c Ramdisk FIT image has correct format
2731 122 common/image.c No ramdisk subimage unit name, using configuration
2732 -122 common/image.c Can't get configuration for ramdisk subimage
2733 123 common/image.c Ramdisk unit name specified
2734 -124 common/image.c Can't get ramdisk subimage node offset
2735 125 common/image.c Got ramdisk subimage node offset
2736 -125 common/image.c Ramdisk subimage hash verification failed
2737 126 common/image.c Ramdisk subimage hash verification OK
2738 -126 common/image.c Ramdisk subimage for unsupported architecture
2739 127 common/image.c Architecture check OK
2740 -127 common/image.c Can't get ramdisk subimage data/size
2741 128 common/image.c Got ramdisk subimage data/size
2742 129 common/image.c Can't get ramdisk load address
2743 -129 common/image.c Got ramdisk load address
2745 -130 common/cmd_doc.c Incorrect FIT image format
2746 131 common/cmd_doc.c FIT image format OK
2748 -140 common/cmd_ide.c Incorrect FIT image format
2749 141 common/cmd_ide.c FIT image format OK
2751 -150 common/cmd_nand.c Incorrect FIT image format
2752 151 common/cmd_nand.c FIT image format OK
2754 - FIT image support:
2756 Enable support for the FIT uImage format.
2758 CONFIG_FIT_BEST_MATCH
2759 When no configuration is explicitly selected, default to the
2760 one whose fdt's compatibility field best matches that of
2761 U-Boot itself. A match is considered "best" if it matches the
2762 most specific compatibility entry of U-Boot's fdt's root node.
2763 The order of entries in the configuration's fdt is ignored.
2765 - Standalone program support:
2766 CONFIG_STANDALONE_LOAD_ADDR
2768 This option defines a board specific value for the
2769 address where standalone program gets loaded, thus
2770 overwriting the architecture dependent default
2773 - Frame Buffer Address:
2776 Define CONFIG_FB_ADDR if you want to use specific
2777 address for frame buffer. This is typically the case
2778 when using a graphics controller has separate video
2779 memory. U-Boot will then place the frame buffer at
2780 the given address instead of dynamically reserving it
2781 in system RAM by calling lcd_setmem(), which grabs
2782 the memory for the frame buffer depending on the
2783 configured panel size.
2785 Please see board_init_f function.
2787 - Automatic software updates via TFTP server
2789 CONFIG_UPDATE_TFTP_CNT_MAX
2790 CONFIG_UPDATE_TFTP_MSEC_MAX
2792 These options enable and control the auto-update feature;
2793 for a more detailed description refer to doc/README.update.
2795 - MTD Support (mtdparts command, UBI support)
2798 Adds the MTD device infrastructure from the Linux kernel.
2799 Needed for mtdparts command support.
2801 CONFIG_MTD_PARTITIONS
2803 Adds the MTD partitioning infrastructure from the Linux
2804 kernel. Needed for UBI support.
2808 Enable building of SPL globally.
2811 LDSCRIPT for linking the SPL binary.
2814 Maximum binary size (text, data and rodata) of the SPL binary.
2816 CONFIG_SPL_TEXT_BASE
2817 TEXT_BASE for linking the SPL binary.
2819 CONFIG_SPL_RELOC_TEXT_BASE
2820 Address to relocate to. If unspecified, this is equal to
2821 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2823 CONFIG_SPL_BSS_START_ADDR
2824 Link address for the BSS within the SPL binary.
2826 CONFIG_SPL_BSS_MAX_SIZE
2827 Maximum binary size of the BSS section of the SPL binary.
2830 Adress of the start of the stack SPL will use
2832 CONFIG_SPL_RELOC_STACK
2833 Adress of the start of the stack SPL will use after
2834 relocation. If unspecified, this is equal to
2837 CONFIG_SYS_SPL_MALLOC_START
2838 Starting address of the malloc pool used in SPL.
2840 CONFIG_SYS_SPL_MALLOC_SIZE
2841 The size of the malloc pool used in SPL.
2843 CONFIG_SPL_FRAMEWORK
2844 Enable the SPL framework under common/. This framework
2845 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2846 NAND loading of the Linux Kernel.
2848 CONFIG_SPL_DISPLAY_PRINT
2849 For ARM, enable an optional function to print more information
2850 about the running system.
2852 CONFIG_SPL_INIT_MINIMAL
2853 Arch init code should be built for a very small image
2855 CONFIG_SPL_LIBCOMMON_SUPPORT
2856 Support for common/libcommon.o in SPL binary
2858 CONFIG_SPL_LIBDISK_SUPPORT
2859 Support for disk/libdisk.o in SPL binary
2861 CONFIG_SPL_I2C_SUPPORT
2862 Support for drivers/i2c/libi2c.o in SPL binary
2864 CONFIG_SPL_GPIO_SUPPORT
2865 Support for drivers/gpio/libgpio.o in SPL binary
2867 CONFIG_SPL_MMC_SUPPORT
2868 Support for drivers/mmc/libmmc.o in SPL binary
2870 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2871 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2872 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2873 Address, size and partition on the MMC to load U-Boot from
2874 when the MMC is being used in raw mode.
2876 CONFIG_SPL_FAT_SUPPORT
2877 Support for fs/fat/libfat.o in SPL binary
2879 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2880 Filename to read to load U-Boot when reading from FAT
2882 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2883 Set this for NAND SPL on PPC mpc83xx targets, so that
2884 start.S waits for the rest of the SPL to load before
2885 continuing (the hardware starts execution after just
2886 loading the first page rather than the full 4K).
2888 CONFIG_SPL_NAND_BASE
2889 Include nand_base.c in the SPL. Requires
2890 CONFIG_SPL_NAND_DRIVERS.
2892 CONFIG_SPL_NAND_DRIVERS
2893 SPL uses normal NAND drivers, not minimal drivers.
2896 Include standard software ECC in the SPL
2898 CONFIG_SPL_NAND_SIMPLE
2899 Support for NAND boot using simple NAND drivers that
2900 expose the cmd_ctrl() interface.
2902 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2903 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2904 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2905 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2906 CONFIG_SYS_NAND_ECCBYTES
2907 Defines the size and behavior of the NAND that SPL uses
2910 CONFIG_SYS_NAND_U_BOOT_OFFS
2911 Location in NAND to read U-Boot from
2913 CONFIG_SYS_NAND_U_BOOT_DST
2914 Location in memory to load U-Boot to
2916 CONFIG_SYS_NAND_U_BOOT_SIZE
2917 Size of image to load
2919 CONFIG_SYS_NAND_U_BOOT_START
2920 Entry point in loaded image to jump to
2922 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2923 Define this if you need to first read the OOB and then the
2924 data. This is used for example on davinci plattforms.
2926 CONFIG_SPL_OMAP3_ID_NAND
2927 Support for an OMAP3-specific set of functions to return the
2928 ID and MFR of the first attached NAND chip, if present.
2930 CONFIG_SPL_SERIAL_SUPPORT
2931 Support for drivers/serial/libserial.o in SPL binary
2933 CONFIG_SPL_SPI_FLASH_SUPPORT
2934 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2936 CONFIG_SPL_SPI_SUPPORT
2937 Support for drivers/spi/libspi.o in SPL binary
2939 CONFIG_SPL_RAM_DEVICE
2940 Support for running image already present in ram, in SPL binary
2942 CONFIG_SPL_LIBGENERIC_SUPPORT
2943 Support for lib/libgeneric.o in SPL binary
2946 Linker address to which the SPL should be padded before
2947 appending the SPL payload.
2950 Final target image containing SPL and payload. Some SPLs
2951 use an arch-specific makefile fragment instead, for
2952 example if more than one image needs to be produced.
2957 [so far only for SMDK2400 boards]
2959 - Modem support enable:
2960 CONFIG_MODEM_SUPPORT
2962 - RTS/CTS Flow control enable:
2965 - Modem debug support:
2966 CONFIG_MODEM_SUPPORT_DEBUG
2968 Enables debugging stuff (char screen[1024], dbg())
2969 for modem support. Useful only with BDI2000.
2971 - Interrupt support (PPC):
2973 There are common interrupt_init() and timer_interrupt()
2974 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2975 for CPU specific initialization. interrupt_init_cpu()
2976 should set decrementer_count to appropriate value. If
2977 CPU resets decrementer automatically after interrupt
2978 (ppc4xx) it should set decrementer_count to zero.
2979 timer_interrupt() calls timer_interrupt_cpu() for CPU
2980 specific handling. If board has watchdog / status_led
2981 / other_activity_monitor it works automatically from
2982 general timer_interrupt().
2986 In the target system modem support is enabled when a
2987 specific key (key combination) is pressed during
2988 power-on. Otherwise U-Boot will boot normally
2989 (autoboot). The key_pressed() function is called from
2990 board_init(). Currently key_pressed() is a dummy
2991 function, returning 1 and thus enabling modem
2994 If there are no modem init strings in the
2995 environment, U-Boot proceed to autoboot; the
2996 previous output (banner, info printfs) will be
2999 See also: doc/README.Modem
3001 Board initialization settings:
3002 ------------------------------
3004 During Initialization u-boot calls a number of board specific functions
3005 to allow the preparation of board specific prerequisites, e.g. pin setup
3006 before drivers are initialized. To enable these callbacks the
3007 following configuration macros have to be defined. Currently this is
3008 architecture specific, so please check arch/your_architecture/lib/board.c
3009 typically in board_init_f() and board_init_r().
3011 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3012 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3013 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3014 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3016 Configuration Settings:
3017 -----------------------
3019 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3020 undefine this when you're short of memory.
3022 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3023 width of the commands listed in the 'help' command output.
3025 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3026 prompt for user input.
3028 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3030 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3032 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3034 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3035 the application (usually a Linux kernel) when it is
3038 - CONFIG_SYS_BAUDRATE_TABLE:
3039 List of legal baudrate settings for this board.
3041 - CONFIG_SYS_CONSOLE_INFO_QUIET
3042 Suppress display of console information at boot.
3044 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3045 If the board specific function
3046 extern int overwrite_console (void);
3047 returns 1, the stdin, stderr and stdout are switched to the
3048 serial port, else the settings in the environment are used.
3050 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3051 Enable the call to overwrite_console().
3053 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3054 Enable overwrite of previous console environment settings.
3056 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3057 Begin and End addresses of the area used by the
3060 - CONFIG_SYS_ALT_MEMTEST:
3061 Enable an alternate, more extensive memory test.
3063 - CONFIG_SYS_MEMTEST_SCRATCH:
3064 Scratch address used by the alternate memory test
3065 You only need to set this if address zero isn't writeable
3067 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3068 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3069 this specified memory area will get subtracted from the top
3070 (end) of RAM and won't get "touched" at all by U-Boot. By
3071 fixing up gd->ram_size the Linux kernel should gets passed
3072 the now "corrected" memory size and won't touch it either.
3073 This should work for arch/ppc and arch/powerpc. Only Linux
3074 board ports in arch/powerpc with bootwrapper support that
3075 recalculate the memory size from the SDRAM controller setup
3076 will have to get fixed in Linux additionally.
3078 This option can be used as a workaround for the 440EPx/GRx
3079 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3082 WARNING: Please make sure that this value is a multiple of
3083 the Linux page size (normally 4k). If this is not the case,
3084 then the end address of the Linux memory will be located at a
3085 non page size aligned address and this could cause major
3088 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3089 Enable temporary baudrate change while serial download
3091 - CONFIG_SYS_SDRAM_BASE:
3092 Physical start address of SDRAM. _Must_ be 0 here.
3094 - CONFIG_SYS_MBIO_BASE:
3095 Physical start address of Motherboard I/O (if using a
3098 - CONFIG_SYS_FLASH_BASE:
3099 Physical start address of Flash memory.
3101 - CONFIG_SYS_MONITOR_BASE:
3102 Physical start address of boot monitor code (set by
3103 make config files to be same as the text base address
3104 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3105 CONFIG_SYS_FLASH_BASE when booting from flash.
3107 - CONFIG_SYS_MONITOR_LEN:
3108 Size of memory reserved for monitor code, used to
3109 determine _at_compile_time_ (!) if the environment is
3110 embedded within the U-Boot image, or in a separate
3113 - CONFIG_SYS_MALLOC_LEN:
3114 Size of DRAM reserved for malloc() use.
3116 - CONFIG_SYS_BOOTM_LEN:
3117 Normally compressed uImages are limited to an
3118 uncompressed size of 8 MBytes. If this is not enough,
3119 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3120 to adjust this setting to your needs.
3122 - CONFIG_SYS_BOOTMAPSZ:
3123 Maximum size of memory mapped by the startup code of
3124 the Linux kernel; all data that must be processed by
3125 the Linux kernel (bd_info, boot arguments, FDT blob if
3126 used) must be put below this limit, unless "bootm_low"
3127 enviroment variable is defined and non-zero. In such case
3128 all data for the Linux kernel must be between "bootm_low"
3129 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3130 variable "bootm_mapsize" will override the value of
3131 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3132 then the value in "bootm_size" will be used instead.
3134 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3135 Enable initrd_high functionality. If defined then the
3136 initrd_high feature is enabled and the bootm ramdisk subcommand
3139 - CONFIG_SYS_BOOT_GET_CMDLINE:
3140 Enables allocating and saving kernel cmdline in space between
3141 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3143 - CONFIG_SYS_BOOT_GET_KBD:
3144 Enables allocating and saving a kernel copy of the bd_info in
3145 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3147 - CONFIG_SYS_MAX_FLASH_BANKS:
3148 Max number of Flash memory banks
3150 - CONFIG_SYS_MAX_FLASH_SECT:
3151 Max number of sectors on a Flash chip
3153 - CONFIG_SYS_FLASH_ERASE_TOUT:
3154 Timeout for Flash erase operations (in ms)
3156 - CONFIG_SYS_FLASH_WRITE_TOUT:
3157 Timeout for Flash write operations (in ms)
3159 - CONFIG_SYS_FLASH_LOCK_TOUT
3160 Timeout for Flash set sector lock bit operation (in ms)
3162 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3163 Timeout for Flash clear lock bits operation (in ms)
3165 - CONFIG_SYS_FLASH_PROTECTION
3166 If defined, hardware flash sectors protection is used
3167 instead of U-Boot software protection.
3169 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3171 Enable TFTP transfers directly to flash memory;
3172 without this option such a download has to be
3173 performed in two steps: (1) download to RAM, and (2)
3174 copy from RAM to flash.
3176 The two-step approach is usually more reliable, since
3177 you can check if the download worked before you erase
3178 the flash, but in some situations (when system RAM is
3179 too limited to allow for a temporary copy of the
3180 downloaded image) this option may be very useful.
3182 - CONFIG_SYS_FLASH_CFI:
3183 Define if the flash driver uses extra elements in the
3184 common flash structure for storing flash geometry.
3186 - CONFIG_FLASH_CFI_DRIVER
3187 This option also enables the building of the cfi_flash driver
3188 in the drivers directory
3190 - CONFIG_FLASH_CFI_MTD
3191 This option enables the building of the cfi_mtd driver
3192 in the drivers directory. The driver exports CFI flash
3195 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3196 Use buffered writes to flash.
3198 - CONFIG_FLASH_SPANSION_S29WS_N
3199 s29ws-n MirrorBit flash has non-standard addresses for buffered
3202 - CONFIG_SYS_FLASH_QUIET_TEST
3203 If this option is defined, the common CFI flash doesn't
3204 print it's warning upon not recognized FLASH banks. This
3205 is useful, if some of the configured banks are only
3206 optionally available.
3208 - CONFIG_FLASH_SHOW_PROGRESS
3209 If defined (must be an integer), print out countdown
3210 digits and dots. Recommended value: 45 (9..1) for 80
3211 column displays, 15 (3..1) for 40 column displays.
3213 - CONFIG_SYS_RX_ETH_BUFFER:
3214 Defines the number of Ethernet receive buffers. On some
3215 Ethernet controllers it is recommended to set this value
3216 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3217 buffers can be full shortly after enabling the interface
3218 on high Ethernet traffic.
3219 Defaults to 4 if not defined.
3221 - CONFIG_ENV_MAX_ENTRIES
3223 Maximum number of entries in the hash table that is used
3224 internally to store the environment settings. The default
3225 setting is supposed to be generous and should work in most
3226 cases. This setting can be used to tune behaviour; see
3227 lib/hashtable.c for details.
3229 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3230 - CONFIG_ENV_FLAGS_LIST_STATIC
3231 Enable validation of the values given to enviroment variables when
3232 calling env set. Variables can be restricted to only decimal,
3233 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3234 the variables can also be restricted to IP address or MAC address.
3236 The format of the list is:
3237 type_attribute = [s|d|x|b|i|m]
3238 access_atribute = [a|r|o|c]
3239 attributes = type_attribute[access_atribute]
3240 entry = variable_name[:attributes]
3243 The type attributes are:
3244 s - String (default)
3247 b - Boolean ([1yYtT|0nNfF])
3251 The access attributes are:
3257 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3258 Define this to a list (string) to define the ".flags"
3259 envirnoment variable in the default or embedded environment.
3261 - CONFIG_ENV_FLAGS_LIST_STATIC
3262 Define this to a list (string) to define validation that
3263 should be done if an entry is not found in the ".flags"
3264 environment variable. To override a setting in the static
3265 list, simply add an entry for the same variable name to the
3268 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3269 If defined, don't allow the -f switch to env set override variable
3272 - CONFIG_SYS_GENERIC_BOARD
3273 This selects the architecture-generic board system instead of the
3274 architecture-specific board files. It is intended to move boards
3275 to this new framework over time. Defining this will disable the
3276 arch/foo/lib/board.c file and use common/board_f.c and
3277 common/board_r.c instead. To use this option your architecture
3278 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3279 its config.mk file). If you find problems enabling this option on
3280 your board please report the problem and send patches!
3282 - CONFIG_SYS_SYM_OFFSETS
3283 This is set by architectures that use offsets for link symbols
3284 instead of absolute values. So bss_start is obtained using an
3285 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3286 directly. You should not need to touch this setting.
3289 The following definitions that deal with the placement and management
3290 of environment data (variable area); in general, we support the
3291 following configurations:
3293 - CONFIG_BUILD_ENVCRC:
3295 Builds up envcrc with the target environment so that external utils
3296 may easily extract it and embed it in final U-Boot images.
3298 - CONFIG_ENV_IS_IN_FLASH:
3300 Define this if the environment is in flash memory.
3302 a) The environment occupies one whole flash sector, which is
3303 "embedded" in the text segment with the U-Boot code. This
3304 happens usually with "bottom boot sector" or "top boot
3305 sector" type flash chips, which have several smaller
3306 sectors at the start or the end. For instance, such a
3307 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3308 such a case you would place the environment in one of the
3309 4 kB sectors - with U-Boot code before and after it. With
3310 "top boot sector" type flash chips, you would put the
3311 environment in one of the last sectors, leaving a gap
3312 between U-Boot and the environment.
3314 - CONFIG_ENV_OFFSET:
3316 Offset of environment data (variable area) to the
3317 beginning of flash memory; for instance, with bottom boot
3318 type flash chips the second sector can be used: the offset
3319 for this sector is given here.
3321 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3325 This is just another way to specify the start address of
3326 the flash sector containing the environment (instead of
3329 - CONFIG_ENV_SECT_SIZE:
3331 Size of the sector containing the environment.
3334 b) Sometimes flash chips have few, equal sized, BIG sectors.
3335 In such a case you don't want to spend a whole sector for
3340 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3341 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3342 of this flash sector for the environment. This saves
3343 memory for the RAM copy of the environment.
3345 It may also save flash memory if you decide to use this
3346 when your environment is "embedded" within U-Boot code,
3347 since then the remainder of the flash sector could be used
3348 for U-Boot code. It should be pointed out that this is
3349 STRONGLY DISCOURAGED from a robustness point of view:
3350 updating the environment in flash makes it always
3351 necessary to erase the WHOLE sector. If something goes
3352 wrong before the contents has been restored from a copy in
3353 RAM, your target system will be dead.
3355 - CONFIG_ENV_ADDR_REDUND
3356 CONFIG_ENV_SIZE_REDUND
3358 These settings describe a second storage area used to hold
3359 a redundant copy of the environment data, so that there is
3360 a valid backup copy in case there is a power failure during
3361 a "saveenv" operation.
3363 BE CAREFUL! Any changes to the flash layout, and some changes to the
3364 source code will make it necessary to adapt <board>/u-boot.lds*
3368 - CONFIG_ENV_IS_IN_NVRAM:
3370 Define this if you have some non-volatile memory device
3371 (NVRAM, battery buffered SRAM) which you want to use for the
3377 These two #defines are used to determine the memory area you
3378 want to use for environment. It is assumed that this memory
3379 can just be read and written to, without any special
3382 BE CAREFUL! The first access to the environment happens quite early
3383 in U-Boot initalization (when we try to get the setting of for the
3384 console baudrate). You *MUST* have mapped your NVRAM area then, or
3387 Please note that even with NVRAM we still use a copy of the
3388 environment in RAM: we could work on NVRAM directly, but we want to
3389 keep settings there always unmodified except somebody uses "saveenv"
3390 to save the current settings.
3393 - CONFIG_ENV_IS_IN_EEPROM:
3395 Use this if you have an EEPROM or similar serial access
3396 device and a driver for it.
3398 - CONFIG_ENV_OFFSET:
3401 These two #defines specify the offset and size of the
3402 environment area within the total memory of your EEPROM.
3404 - CONFIG_SYS_I2C_EEPROM_ADDR:
3405 If defined, specified the chip address of the EEPROM device.
3406 The default address is zero.
3408 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3409 If defined, the number of bits used to address bytes in a
3410 single page in the EEPROM device. A 64 byte page, for example
3411 would require six bits.
3413 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3414 If defined, the number of milliseconds to delay between
3415 page writes. The default is zero milliseconds.
3417 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3418 The length in bytes of the EEPROM memory array address. Note
3419 that this is NOT the chip address length!
3421 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3422 EEPROM chips that implement "address overflow" are ones
3423 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3424 address and the extra bits end up in the "chip address" bit
3425 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3428 Note that we consider the length of the address field to
3429 still be one byte because the extra address bits are hidden
3430 in the chip address.
3432 - CONFIG_SYS_EEPROM_SIZE:
3433 The size in bytes of the EEPROM device.
3435 - CONFIG_ENV_EEPROM_IS_ON_I2C
3436 define this, if you have I2C and SPI activated, and your
3437 EEPROM, which holds the environment, is on the I2C bus.
3439 - CONFIG_I2C_ENV_EEPROM_BUS
3440 if you have an Environment on an EEPROM reached over
3441 I2C muxes, you can define here, how to reach this
3442 EEPROM. For example:
3444 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3446 EEPROM which holds the environment, is reached over
3447 a pca9547 i2c mux with address 0x70, channel 3.
3449 - CONFIG_ENV_IS_IN_DATAFLASH:
3451 Define this if you have a DataFlash memory device which you
3452 want to use for the environment.
3454 - CONFIG_ENV_OFFSET:
3458 These three #defines specify the offset and size of the
3459 environment area within the total memory of your DataFlash placed
3460 at the specified address.
3462 - CONFIG_ENV_IS_IN_REMOTE:
3464 Define this if you have a remote memory space which you
3465 want to use for the local device's environment.
3470 These two #defines specify the address and size of the
3471 environment area within the remote memory space. The
3472 local device can get the environment from remote memory
3473 space by SRIO or PCIE links.
3475 BE CAREFUL! For some special cases, the local device can not use
3476 "saveenv" command. For example, the local device will get the
3477 environment stored in a remote NOR flash by SRIO or PCIE link,
3478 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3480 - CONFIG_ENV_IS_IN_NAND:
3482 Define this if you have a NAND device which you want to use
3483 for the environment.
3485 - CONFIG_ENV_OFFSET:
3488 These two #defines specify the offset and size of the environment
3489 area within the first NAND device. CONFIG_ENV_OFFSET must be
3490 aligned to an erase block boundary.
3492 - CONFIG_ENV_OFFSET_REDUND (optional):
3494 This setting describes a second storage area of CONFIG_ENV_SIZE
3495 size used to hold a redundant copy of the environment data, so
3496 that there is a valid backup copy in case there is a power failure
3497 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3498 aligned to an erase block boundary.
3500 - CONFIG_ENV_RANGE (optional):
3502 Specifies the length of the region in which the environment
3503 can be written. This should be a multiple of the NAND device's
3504 block size. Specifying a range with more erase blocks than
3505 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3506 the range to be avoided.
3508 - CONFIG_ENV_OFFSET_OOB (optional):
3510 Enables support for dynamically retrieving the offset of the
3511 environment from block zero's out-of-band data. The
3512 "nand env.oob" command can be used to record this offset.
3513 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3514 using CONFIG_ENV_OFFSET_OOB.
3516 - CONFIG_NAND_ENV_DST
3518 Defines address in RAM to which the nand_spl code should copy the
3519 environment. If redundant environment is used, it will be copied to
3520 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3522 - CONFIG_SYS_SPI_INIT_OFFSET
3524 Defines offset to the initial SPI buffer area in DPRAM. The
3525 area is used at an early stage (ROM part) if the environment
3526 is configured to reside in the SPI EEPROM: We need a 520 byte
3527 scratch DPRAM area. It is used between the two initialization
3528 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3529 to be a good choice since it makes it far enough from the
3530 start of the data area as well as from the stack pointer.
3532 Please note that the environment is read-only until the monitor
3533 has been relocated to RAM and a RAM copy of the environment has been
3534 created; also, when using EEPROM you will have to use getenv_f()
3535 until then to read environment variables.
3537 The environment is protected by a CRC32 checksum. Before the monitor
3538 is relocated into RAM, as a result of a bad CRC you will be working
3539 with the compiled-in default environment - *silently*!!! [This is
3540 necessary, because the first environment variable we need is the
3541 "baudrate" setting for the console - if we have a bad CRC, we don't
3542 have any device yet where we could complain.]
3544 Note: once the monitor has been relocated, then it will complain if
3545 the default environment is used; a new CRC is computed as soon as you
3546 use the "saveenv" command to store a valid environment.
3548 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3549 Echo the inverted Ethernet link state to the fault LED.
3551 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3552 also needs to be defined.
3554 - CONFIG_SYS_FAULT_MII_ADDR:
3555 MII address of the PHY to check for the Ethernet link state.
3557 - CONFIG_NS16550_MIN_FUNCTIONS:
3558 Define this if you desire to only have use of the NS16550_init
3559 and NS16550_putc functions for the serial driver located at
3560 drivers/serial/ns16550.c. This option is useful for saving
3561 space for already greatly restricted images, including but not
3562 limited to NAND_SPL configurations.
3564 - CONFIG_DISPLAY_BOARDINFO
3565 Display information about the board that U-Boot is running on
3566 when U-Boot starts up. The board function checkboard() is called
3569 - CONFIG_DISPLAY_BOARDINFO_LATE
3570 Similar to the previous option, but display this information
3571 later, once stdio is running and output goes to the LCD, if
3574 Low Level (hardware related) configuration options:
3575 ---------------------------------------------------
3577 - CONFIG_SYS_CACHELINE_SIZE:
3578 Cache Line Size of the CPU.
3580 - CONFIG_SYS_DEFAULT_IMMR:
3581 Default address of the IMMR after system reset.
3583 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3584 and RPXsuper) to be able to adjust the position of
3585 the IMMR register after a reset.
3587 - CONFIG_SYS_CCSRBAR_DEFAULT:
3588 Default (power-on reset) physical address of CCSR on Freescale
3591 - CONFIG_SYS_CCSRBAR:
3592 Virtual address of CCSR. On a 32-bit build, this is typically
3593 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3595 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3596 for cross-platform code that uses that macro instead.
3598 - CONFIG_SYS_CCSRBAR_PHYS:
3599 Physical address of CCSR. CCSR can be relocated to a new
3600 physical address, if desired. In this case, this macro should
3601 be set to that address. Otherwise, it should be set to the
3602 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3603 is typically relocated on 36-bit builds. It is recommended
3604 that this macro be defined via the _HIGH and _LOW macros:
3606 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3607 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3609 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3610 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3611 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3612 used in assembly code, so it must not contain typecasts or
3613 integer size suffixes (e.g. "ULL").
3615 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3616 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3617 used in assembly code, so it must not contain typecasts or
3618 integer size suffixes (e.g. "ULL").
3620 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3621 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3622 forced to a value that ensures that CCSR is not relocated.
3624 - Floppy Disk Support:
3625 CONFIG_SYS_FDC_DRIVE_NUMBER
3627 the default drive number (default value 0)
3629 CONFIG_SYS_ISA_IO_STRIDE
3631 defines the spacing between FDC chipset registers
3634 CONFIG_SYS_ISA_IO_OFFSET
3636 defines the offset of register from address. It
3637 depends on which part of the data bus is connected to
3638 the FDC chipset. (default value 0)
3640 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3641 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3644 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3645 fdc_hw_init() is called at the beginning of the FDC
3646 setup. fdc_hw_init() must be provided by the board
3647 source code. It is used to make hardware dependant
3651 Most IDE controllers were designed to be connected with PCI
3652 interface. Only few of them were designed for AHB interface.
3653 When software is doing ATA command and data transfer to
3654 IDE devices through IDE-AHB controller, some additional
3655 registers accessing to these kind of IDE-AHB controller
3658 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3659 DO NOT CHANGE unless you know exactly what you're
3660 doing! (11-4) [MPC8xx/82xx systems only]
3662 - CONFIG_SYS_INIT_RAM_ADDR:
3664 Start address of memory area that can be used for
3665 initial data and stack; please note that this must be
3666 writable memory that is working WITHOUT special
3667 initialization, i. e. you CANNOT use normal RAM which
3668 will become available only after programming the
3669 memory controller and running certain initialization
3672 U-Boot uses the following memory types:
3673 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3674 - MPC824X: data cache
3675 - PPC4xx: data cache
3677 - CONFIG_SYS_GBL_DATA_OFFSET:
3679 Offset of the initial data structure in the memory
3680 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3681 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3682 data is located at the end of the available space
3683 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3684 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3685 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3686 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3689 On the MPC824X (or other systems that use the data
3690 cache for initial memory) the address chosen for
3691 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3692 point to an otherwise UNUSED address space between
3693 the top of RAM and the start of the PCI space.
3695 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3697 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3699 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3701 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3703 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3705 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3707 - CONFIG_SYS_OR_TIMING_SDRAM:
3710 - CONFIG_SYS_MAMR_PTA:
3711 periodic timer for refresh
3713 - CONFIG_SYS_DER: Debug Event Register (37-47)
3715 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3716 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3717 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3718 CONFIG_SYS_BR1_PRELIM:
3719 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3721 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3722 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3723 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3724 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3726 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3727 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3728 Machine Mode Register and Memory Periodic Timer
3729 Prescaler definitions (SDRAM timing)
3731 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3732 enable I2C microcode relocation patch (MPC8xx);
3733 define relocation offset in DPRAM [DSP2]
3735 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3736 enable SMC microcode relocation patch (MPC8xx);
3737 define relocation offset in DPRAM [SMC1]
3739 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3740 enable SPI microcode relocation patch (MPC8xx);
3741 define relocation offset in DPRAM [SCC4]
3743 - CONFIG_SYS_USE_OSCCLK:
3744 Use OSCM clock mode on MBX8xx board. Be careful,
3745 wrong setting might damage your board. Read
3746 doc/README.MBX before setting this variable!
3748 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3749 Offset of the bootmode word in DPRAM used by post
3750 (Power On Self Tests). This definition overrides
3751 #define'd default value in commproc.h resp.
3754 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3755 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3756 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3757 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3758 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3759 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3760 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3761 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3762 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3764 - CONFIG_PCI_DISABLE_PCIE:
3765 Disable PCI-Express on systems where it is supported but not
3768 - CONFIG_PCI_ENUM_ONLY
3769 Only scan through and get the devices on the busses.
3770 Don't do any setup work, presumably because someone or
3771 something has already done it, and we don't need to do it
3772 a second time. Useful for platforms that are pre-booted
3773 by coreboot or similar.
3776 Chip has SRIO or not
3779 Board has SRIO 1 port available
3782 Board has SRIO 2 port available
3784 - CONFIG_SYS_SRIOn_MEM_VIRT:
3785 Virtual Address of SRIO port 'n' memory region
3787 - CONFIG_SYS_SRIOn_MEM_PHYS:
3788 Physical Address of SRIO port 'n' memory region
3790 - CONFIG_SYS_SRIOn_MEM_SIZE:
3791 Size of SRIO port 'n' memory region
3793 - CONFIG_SYS_NDFC_16
3794 Defined to tell the NDFC that the NAND chip is using a
3797 - CONFIG_SYS_NDFC_EBC0_CFG
3798 Sets the EBC0_CFG register for the NDFC. If not defined
3799 a default value will be used.
3802 Get DDR timing information from an I2C EEPROM. Common
3803 with pluggable memory modules such as SODIMMs
3806 I2C address of the SPD EEPROM
3808 - CONFIG_SYS_SPD_BUS_NUM
3809 If SPD EEPROM is on an I2C bus other than the first
3810 one, specify here. Note that the value must resolve
3811 to something your driver can deal with.
3813 - CONFIG_SYS_DDR_RAW_TIMING
3814 Get DDR timing information from other than SPD. Common with
3815 soldered DDR chips onboard without SPD. DDR raw timing
3816 parameters are extracted from datasheet and hard-coded into
3817 header files or board specific files.
3819 - CONFIG_FSL_DDR_INTERACTIVE
3820 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3822 - CONFIG_SYS_83XX_DDR_USES_CS0
3823 Only for 83xx systems. If specified, then DDR should
3824 be configured using CS0 and CS1 instead of CS2 and CS3.
3826 - CONFIG_ETHER_ON_FEC[12]
3827 Define to enable FEC[12] on a 8xx series processor.
3829 - CONFIG_FEC[12]_PHY
3830 Define to the hardcoded PHY address which corresponds
3831 to the given FEC; i. e.
3832 #define CONFIG_FEC1_PHY 4
3833 means that the PHY with address 4 is connected to FEC1
3835 When set to -1, means to probe for first available.
3837 - CONFIG_FEC[12]_PHY_NORXERR
3838 The PHY does not have a RXERR line (RMII only).
3839 (so program the FEC to ignore it).
3842 Enable RMII mode for all FECs.
3843 Note that this is a global option, we can't
3844 have one FEC in standard MII mode and another in RMII mode.
3846 - CONFIG_CRC32_VERIFY
3847 Add a verify option to the crc32 command.
3850 => crc32 -v <address> <count> <crc32>
3852 Where address/count indicate a memory area
3853 and crc32 is the correct crc32 which the
3857 Add the "loopw" memory command. This only takes effect if
3858 the memory commands are activated globally (CONFIG_CMD_MEM).
3861 Add the "mdc" and "mwc" memory commands. These are cyclic
3866 This command will print 4 bytes (10,11,12,13) each 500 ms.
3868 => mwc.l 100 12345678 10
3869 This command will write 12345678 to address 100 all 10 ms.
3871 This only takes effect if the memory commands are activated
3872 globally (CONFIG_CMD_MEM).
3874 - CONFIG_SKIP_LOWLEVEL_INIT
3875 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3876 low level initializations (like setting up the memory
3877 controller) are omitted and/or U-Boot does not
3878 relocate itself into RAM.
3880 Normally this variable MUST NOT be defined. The only
3881 exception is when U-Boot is loaded (to RAM) by some
3882 other boot loader or by a debugger which performs
3883 these initializations itself.
3886 Modifies the behaviour of start.S when compiling a loader
3887 that is executed before the actual U-Boot. E.g. when
3888 compiling a NAND SPL.
3890 - CONFIG_ARCH_MAP_SYSMEM
3891 Generally U-Boot (and in particular the md command) uses
3892 effective address. It is therefore not necessary to regard
3893 U-Boot address as virtual addresses that need to be translated
3894 to physical addresses. However, sandbox requires this, since
3895 it maintains its own little RAM buffer which contains all
3896 addressable memory. This option causes some memory accesses
3897 to be mapped through map_sysmem() / unmap_sysmem().
3899 - CONFIG_USE_ARCH_MEMCPY
3900 CONFIG_USE_ARCH_MEMSET
3901 If these options are used a optimized version of memcpy/memset will
3902 be used if available. These functions may be faster under some
3903 conditions but may increase the binary size.
3905 - CONFIG_X86_RESET_VECTOR
3906 If defined, the x86 reset vector code is included. This is not
3907 needed when U-Boot is running from Coreboot.
3910 Defines the MPU clock speed (in MHz).
3912 NOTE : currently only supported on AM335x platforms.
3914 Freescale QE/FMAN Firmware Support:
3915 -----------------------------------
3917 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3918 loading of "firmware", which is encoded in the QE firmware binary format.
3919 This firmware often needs to be loaded during U-Boot booting, so macros
3920 are used to identify the storage device (NOR flash, SPI, etc) and the address
3923 - CONFIG_SYS_QE_FMAN_FW_ADDR
3924 The address in the storage device where the firmware is located. The
3925 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3928 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3929 The maximum possible size of the firmware. The firmware binary format
3930 has a field that specifies the actual size of the firmware, but it
3931 might not be possible to read any part of the firmware unless some
3932 local storage is allocated to hold the entire firmware first.
3934 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3935 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3936 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3937 virtual address in NOR flash.
3939 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3940 Specifies that QE/FMAN firmware is located in NAND flash.
3941 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3943 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3944 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3945 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3947 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3948 Specifies that QE/FMAN firmware is located on the primary SPI
3949 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3951 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3952 Specifies that QE/FMAN firmware is located in the remote (master)
3953 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3954 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3955 window->master inbound window->master LAW->the ucode address in
3956 master's memory space.
3958 Building the Software:
3959 ======================
3961 Building U-Boot has been tested in several native build environments
3962 and in many different cross environments. Of course we cannot support
3963 all possibly existing versions of cross development tools in all
3964 (potentially obsolete) versions. In case of tool chain problems we
3965 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3966 which is extensively used to build and test U-Boot.
3968 If you are not using a native environment, it is assumed that you
3969 have GNU cross compiling tools available in your path. In this case,
3970 you must set the environment variable CROSS_COMPILE in your shell.
3971 Note that no changes to the Makefile or any other source files are
3972 necessary. For example using the ELDK on a 4xx CPU, please enter:
3974 $ CROSS_COMPILE=ppc_4xx-
3975 $ export CROSS_COMPILE
3977 Note: If you wish to generate Windows versions of the utilities in
3978 the tools directory you can use the MinGW toolchain
3979 (http://www.mingw.org). Set your HOST tools to the MinGW
3980 toolchain and execute 'make tools'. For example:
3982 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3984 Binaries such as tools/mkimage.exe will be created which can
3985 be executed on computers running Windows.
3987 U-Boot is intended to be simple to build. After installing the
3988 sources you must configure U-Boot for one specific board type. This
3993 where "NAME_config" is the name of one of the existing configu-
3994 rations; see boards.cfg for supported names.
3996 Note: for some board special configuration names may exist; check if
3997 additional information is available from the board vendor; for
3998 instance, the TQM823L systems are available without (standard)
3999 or with LCD support. You can select such additional "features"
4000 when choosing the configuration, i. e.
4003 - will configure for a plain TQM823L, i. e. no LCD support
4005 make TQM823L_LCD_config
4006 - will configure for a TQM823L with U-Boot console on LCD
4011 Finally, type "make all", and you should get some working U-Boot
4012 images ready for download to / installation on your system:
4014 - "u-boot.bin" is a raw binary image
4015 - "u-boot" is an image in ELF binary format
4016 - "u-boot.srec" is in Motorola S-Record format
4018 By default the build is performed locally and the objects are saved
4019 in the source directory. One of the two methods can be used to change
4020 this behavior and build U-Boot to some external directory:
4022 1. Add O= to the make command line invocations:
4024 make O=/tmp/build distclean
4025 make O=/tmp/build NAME_config
4026 make O=/tmp/build all
4028 2. Set environment variable BUILD_DIR to point to the desired location:
4030 export BUILD_DIR=/tmp/build
4035 Note that the command line "O=" setting overrides the BUILD_DIR environment
4039 Please be aware that the Makefiles assume you are using GNU make, so
4040 for instance on NetBSD you might need to use "gmake" instead of
4044 If the system board that you have is not listed, then you will need
4045 to port U-Boot to your hardware platform. To do this, follow these
4048 1. Add a new configuration option for your board to the toplevel
4049 "boards.cfg" file, using the existing entries as examples.
4050 Follow the instructions there to keep the boards in order.
4051 2. Create a new directory to hold your board specific code. Add any
4052 files you need. In your board directory, you will need at least
4053 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4054 3. Create a new configuration file "include/configs/<board>.h" for
4056 3. If you're porting U-Boot to a new CPU, then also create a new
4057 directory to hold your CPU specific code. Add any files you need.
4058 4. Run "make <board>_config" with your new name.
4059 5. Type "make", and you should get a working "u-boot.srec" file
4060 to be installed on your target system.
4061 6. Debug and solve any problems that might arise.
4062 [Of course, this last step is much harder than it sounds.]
4065 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4066 ==============================================================
4068 If you have modified U-Boot sources (for instance added a new board
4069 or support for new devices, a new CPU, etc.) you are expected to
4070 provide feedback to the other developers. The feedback normally takes
4071 the form of a "patch", i. e. a context diff against a certain (latest
4072 official or latest in the git repository) version of U-Boot sources.
4074 But before you submit such a patch, please verify that your modifi-
4075 cation did not break existing code. At least make sure that *ALL* of
4076 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4077 just run the "MAKEALL" script, which will configure and build U-Boot
4078 for ALL supported system. Be warned, this will take a while. You can
4079 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4080 environment variable to the script, i. e. to use the ELDK cross tools
4083 CROSS_COMPILE=ppc_8xx- MAKEALL
4085 or to build on a native PowerPC system you can type
4087 CROSS_COMPILE=' ' MAKEALL
4089 When using the MAKEALL script, the default behaviour is to build
4090 U-Boot in the source directory. This location can be changed by
4091 setting the BUILD_DIR environment variable. Also, for each target
4092 built, the MAKEALL script saves two log files (<target>.ERR and
4093 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4094 location can be changed by setting the MAKEALL_LOGDIR environment
4095 variable. For example:
4097 export BUILD_DIR=/tmp/build
4098 export MAKEALL_LOGDIR=/tmp/log
4099 CROSS_COMPILE=ppc_8xx- MAKEALL
4101 With the above settings build objects are saved in the /tmp/build,
4102 log files are saved in the /tmp/log and the source tree remains clean
4103 during the whole build process.
4106 See also "U-Boot Porting Guide" below.
4109 Monitor Commands - Overview:
4110 ============================
4112 go - start application at address 'addr'
4113 run - run commands in an environment variable
4114 bootm - boot application image from memory
4115 bootp - boot image via network using BootP/TFTP protocol
4116 bootz - boot zImage from memory
4117 tftpboot- boot image via network using TFTP protocol
4118 and env variables "ipaddr" and "serverip"
4119 (and eventually "gatewayip")
4120 tftpput - upload a file via network using TFTP protocol
4121 rarpboot- boot image via network using RARP/TFTP protocol
4122 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4123 loads - load S-Record file over serial line
4124 loadb - load binary file over serial line (kermit mode)
4126 mm - memory modify (auto-incrementing)
4127 nm - memory modify (constant address)
4128 mw - memory write (fill)
4130 cmp - memory compare
4131 crc32 - checksum calculation
4132 i2c - I2C sub-system
4133 sspi - SPI utility commands
4134 base - print or set address offset
4135 printenv- print environment variables
4136 setenv - set environment variables
4137 saveenv - save environment variables to persistent storage
4138 protect - enable or disable FLASH write protection
4139 erase - erase FLASH memory
4140 flinfo - print FLASH memory information
4141 nand - NAND memory operations (see doc/README.nand)
4142 bdinfo - print Board Info structure
4143 iminfo - print header information for application image
4144 coninfo - print console devices and informations
4145 ide - IDE sub-system
4146 loop - infinite loop on address range
4147 loopw - infinite write loop on address range
4148 mtest - simple RAM test
4149 icache - enable or disable instruction cache
4150 dcache - enable or disable data cache
4151 reset - Perform RESET of the CPU
4152 echo - echo args to console
4153 version - print monitor version
4154 help - print online help
4155 ? - alias for 'help'
4158 Monitor Commands - Detailed Description:
4159 ========================================
4163 For now: just type "help <command>".
4166 Environment Variables:
4167 ======================
4169 U-Boot supports user configuration using Environment Variables which
4170 can be made persistent by saving to Flash memory.
4172 Environment Variables are set using "setenv", printed using
4173 "printenv", and saved to Flash using "saveenv". Using "setenv"
4174 without a value can be used to delete a variable from the
4175 environment. As long as you don't save the environment you are
4176 working with an in-memory copy. In case the Flash area containing the
4177 environment is erased by accident, a default environment is provided.
4179 Some configuration options can be set using Environment Variables.
4181 List of environment variables (most likely not complete):
4183 baudrate - see CONFIG_BAUDRATE
4185 bootdelay - see CONFIG_BOOTDELAY
4187 bootcmd - see CONFIG_BOOTCOMMAND
4189 bootargs - Boot arguments when booting an RTOS image
4191 bootfile - Name of the image to load with TFTP
4193 bootm_low - Memory range available for image processing in the bootm
4194 command can be restricted. This variable is given as
4195 a hexadecimal number and defines lowest address allowed
4196 for use by the bootm command. See also "bootm_size"
4197 environment variable. Address defined by "bootm_low" is
4198 also the base of the initial memory mapping for the Linux
4199 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4202 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4203 This variable is given as a hexadecimal number and it
4204 defines the size of the memory region starting at base
4205 address bootm_low that is accessible by the Linux kernel
4206 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4207 as the default value if it is defined, and bootm_size is
4210 bootm_size - Memory range available for image processing in the bootm
4211 command can be restricted. This variable is given as
4212 a hexadecimal number and defines the size of the region
4213 allowed for use by the bootm command. See also "bootm_low"
4214 environment variable.
4216 updatefile - Location of the software update file on a TFTP server, used
4217 by the automatic software update feature. Please refer to
4218 documentation in doc/README.update for more details.
4220 autoload - if set to "no" (any string beginning with 'n'),
4221 "bootp" will just load perform a lookup of the
4222 configuration from the BOOTP server, but not try to
4223 load any image using TFTP
4225 autostart - if set to "yes", an image loaded using the "bootp",
4226 "rarpboot", "tftpboot" or "diskboot" commands will
4227 be automatically started (by internally calling
4230 If set to "no", a standalone image passed to the
4231 "bootm" command will be copied to the load address
4232 (and eventually uncompressed), but NOT be started.
4233 This can be used to load and uncompress arbitrary
4236 fdt_high - if set this restricts the maximum address that the
4237 flattened device tree will be copied into upon boot.
4238 For example, if you have a system with 1 GB memory
4239 at physical address 0x10000000, while Linux kernel
4240 only recognizes the first 704 MB as low memory, you
4241 may need to set fdt_high as 0x3C000000 to have the
4242 device tree blob be copied to the maximum address
4243 of the 704 MB low memory, so that Linux kernel can
4244 access it during the boot procedure.
4246 If this is set to the special value 0xFFFFFFFF then
4247 the fdt will not be copied at all on boot. For this
4248 to work it must reside in writable memory, have
4249 sufficient padding on the end of it for u-boot to
4250 add the information it needs into it, and the memory
4251 must be accessible by the kernel.
4253 fdtcontroladdr- if set this is the address of the control flattened
4254 device tree used by U-Boot when CONFIG_OF_CONTROL is
4257 i2cfast - (PPC405GP|PPC405EP only)
4258 if set to 'y' configures Linux I2C driver for fast
4259 mode (400kHZ). This environment variable is used in
4260 initialization code. So, for changes to be effective
4261 it must be saved and board must be reset.
4263 initrd_high - restrict positioning of initrd images:
4264 If this variable is not set, initrd images will be
4265 copied to the highest possible address in RAM; this
4266 is usually what you want since it allows for
4267 maximum initrd size. If for some reason you want to
4268 make sure that the initrd image is loaded below the
4269 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4270 variable to a value of "no" or "off" or "0".
4271 Alternatively, you can set it to a maximum upper
4272 address to use (U-Boot will still check that it
4273 does not overwrite the U-Boot stack and data).
4275 For instance, when you have a system with 16 MB
4276 RAM, and want to reserve 4 MB from use by Linux,
4277 you can do this by adding "mem=12M" to the value of
4278 the "bootargs" variable. However, now you must make
4279 sure that the initrd image is placed in the first
4280 12 MB as well - this can be done with
4282 setenv initrd_high 00c00000
4284 If you set initrd_high to 0xFFFFFFFF, this is an
4285 indication to U-Boot that all addresses are legal
4286 for the Linux kernel, including addresses in flash
4287 memory. In this case U-Boot will NOT COPY the
4288 ramdisk at all. This may be useful to reduce the
4289 boot time on your system, but requires that this
4290 feature is supported by your Linux kernel.
4292 ipaddr - IP address; needed for tftpboot command
4294 loadaddr - Default load address for commands like "bootp",
4295 "rarpboot", "tftpboot", "loadb" or "diskboot"
4297 loads_echo - see CONFIG_LOADS_ECHO
4299 serverip - TFTP server IP address; needed for tftpboot command
4301 bootretry - see CONFIG_BOOT_RETRY_TIME
4303 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4305 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4307 ethprime - controls which interface is used first.
4309 ethact - controls which interface is currently active.
4310 For example you can do the following
4312 => setenv ethact FEC
4313 => ping 192.168.0.1 # traffic sent on FEC
4314 => setenv ethact SCC
4315 => ping 10.0.0.1 # traffic sent on SCC
4317 ethrotate - When set to "no" U-Boot does not go through all
4318 available network interfaces.
4319 It just stays at the currently selected interface.
4321 netretry - When set to "no" each network operation will
4322 either succeed or fail without retrying.
4323 When set to "once" the network operation will
4324 fail when all the available network interfaces
4325 are tried once without success.
4326 Useful on scripts which control the retry operation
4329 npe_ucode - set load address for the NPE microcode
4331 tftpsrcport - If this is set, the value is used for TFTP's
4334 tftpdstport - If this is set, the value is used for TFTP's UDP
4335 destination port instead of the Well Know Port 69.
4337 tftpblocksize - Block size to use for TFTP transfers; if not set,
4338 we use the TFTP server's default block size
4340 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4341 seconds, minimum value is 1000 = 1 second). Defines
4342 when a packet is considered to be lost so it has to
4343 be retransmitted. The default is 5000 = 5 seconds.
4344 Lowering this value may make downloads succeed
4345 faster in networks with high packet loss rates or
4346 with unreliable TFTP servers.
4348 vlan - When set to a value < 4095 the traffic over
4349 Ethernet is encapsulated/received over 802.1q
4352 The following image location variables contain the location of images
4353 used in booting. The "Image" column gives the role of the image and is
4354 not an environment variable name. The other columns are environment
4355 variable names. "File Name" gives the name of the file on a TFTP
4356 server, "RAM Address" gives the location in RAM the image will be
4357 loaded to, and "Flash Location" gives the image's address in NOR
4358 flash or offset in NAND flash.
4360 *Note* - these variables don't have to be defined for all boards, some
4361 boards currenlty use other variables for these purposes, and some
4362 boards use these variables for other purposes.
4364 Image File Name RAM Address Flash Location
4365 ----- --------- ----------- --------------
4366 u-boot u-boot u-boot_addr_r u-boot_addr
4367 Linux kernel bootfile kernel_addr_r kernel_addr
4368 device tree blob fdtfile fdt_addr_r fdt_addr
4369 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4371 The following environment variables may be used and automatically
4372 updated by the network boot commands ("bootp" and "rarpboot"),
4373 depending the information provided by your boot server:
4375 bootfile - see above
4376 dnsip - IP address of your Domain Name Server
4377 dnsip2 - IP address of your secondary Domain Name Server
4378 gatewayip - IP address of the Gateway (Router) to use
4379 hostname - Target hostname
4381 netmask - Subnet Mask
4382 rootpath - Pathname of the root filesystem on the NFS server
4383 serverip - see above
4386 There are two special Environment Variables:
4388 serial# - contains hardware identification information such
4389 as type string and/or serial number
4390 ethaddr - Ethernet address
4392 These variables can be set only once (usually during manufacturing of
4393 the board). U-Boot refuses to delete or overwrite these variables
4394 once they have been set once.
4397 Further special Environment Variables:
4399 ver - Contains the U-Boot version string as printed
4400 with the "version" command. This variable is
4401 readonly (see CONFIG_VERSION_VARIABLE).
4404 Please note that changes to some configuration parameters may take
4405 only effect after the next boot (yes, that's just like Windoze :-).
4408 Callback functions for environment variables:
4409 ---------------------------------------------
4411 For some environment variables, the behavior of u-boot needs to change
4412 when their values are changed. This functionailty allows functions to
4413 be associated with arbitrary variables. On creation, overwrite, or
4414 deletion, the callback will provide the opportunity for some side
4415 effect to happen or for the change to be rejected.
4417 The callbacks are named and associated with a function using the
4418 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4420 These callbacks are associated with variables in one of two ways. The
4421 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4422 in the board configuration to a string that defines a list of
4423 associations. The list must be in the following format:
4425 entry = variable_name[:callback_name]
4428 If the callback name is not specified, then the callback is deleted.
4429 Spaces are also allowed anywhere in the list.
4431 Callbacks can also be associated by defining the ".callbacks" variable
4432 with the same list format above. Any association in ".callbacks" will
4433 override any association in the static list. You can define
4434 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4435 ".callbacks" envirnoment variable in the default or embedded environment.
4438 Command Line Parsing:
4439 =====================
4441 There are two different command line parsers available with U-Boot:
4442 the old "simple" one, and the much more powerful "hush" shell:
4444 Old, simple command line parser:
4445 --------------------------------
4447 - supports environment variables (through setenv / saveenv commands)
4448 - several commands on one line, separated by ';'
4449 - variable substitution using "... ${name} ..." syntax
4450 - special characters ('$', ';') can be escaped by prefixing with '\',
4452 setenv bootcmd bootm \${address}
4453 - You can also escape text by enclosing in single apostrophes, for example:
4454 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4459 - similar to Bourne shell, with control structures like
4460 if...then...else...fi, for...do...done; while...do...done,
4461 until...do...done, ...
4462 - supports environment ("global") variables (through setenv / saveenv
4463 commands) and local shell variables (through standard shell syntax
4464 "name=value"); only environment variables can be used with "run"
4470 (1) If a command line (or an environment variable executed by a "run"
4471 command) contains several commands separated by semicolon, and
4472 one of these commands fails, then the remaining commands will be
4475 (2) If you execute several variables with one call to run (i. e.
4476 calling run with a list of variables as arguments), any failing
4477 command will cause "run" to terminate, i. e. the remaining
4478 variables are not executed.
4480 Note for Redundant Ethernet Interfaces:
4481 =======================================
4483 Some boards come with redundant Ethernet interfaces; U-Boot supports
4484 such configurations and is capable of automatic selection of a
4485 "working" interface when needed. MAC assignment works as follows:
4487 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4488 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4489 "eth1addr" (=>eth1), "eth2addr", ...
4491 If the network interface stores some valid MAC address (for instance
4492 in SROM), this is used as default address if there is NO correspon-
4493 ding setting in the environment; if the corresponding environment
4494 variable is set, this overrides the settings in the card; that means:
4496 o If the SROM has a valid MAC address, and there is no address in the
4497 environment, the SROM's address is used.
4499 o If there is no valid address in the SROM, and a definition in the
4500 environment exists, then the value from the environment variable is
4503 o If both the SROM and the environment contain a MAC address, and
4504 both addresses are the same, this MAC address is used.
4506 o If both the SROM and the environment contain a MAC address, and the
4507 addresses differ, the value from the environment is used and a
4510 o If neither SROM nor the environment contain a MAC address, an error
4513 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4514 will be programmed into hardware as part of the initialization process. This
4515 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4516 The naming convention is as follows:
4517 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4522 U-Boot is capable of booting (and performing other auxiliary operations on)
4523 images in two formats:
4525 New uImage format (FIT)
4526 -----------------------
4528 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4529 to Flattened Device Tree). It allows the use of images with multiple
4530 components (several kernels, ramdisks, etc.), with contents protected by
4531 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4537 Old image format is based on binary files which can be basically anything,
4538 preceded by a special header; see the definitions in include/image.h for
4539 details; basically, the header defines the following image properties:
4541 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4542 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4543 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4544 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4546 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4547 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4548 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4549 * Compression Type (uncompressed, gzip, bzip2)
4555 The header is marked by a special Magic Number, and both the header
4556 and the data portions of the image are secured against corruption by
4563 Although U-Boot should support any OS or standalone application
4564 easily, the main focus has always been on Linux during the design of
4567 U-Boot includes many features that so far have been part of some
4568 special "boot loader" code within the Linux kernel. Also, any
4569 "initrd" images to be used are no longer part of one big Linux image;
4570 instead, kernel and "initrd" are separate images. This implementation
4571 serves several purposes:
4573 - the same features can be used for other OS or standalone
4574 applications (for instance: using compressed images to reduce the
4575 Flash memory footprint)
4577 - it becomes much easier to port new Linux kernel versions because
4578 lots of low-level, hardware dependent stuff are done by U-Boot
4580 - the same Linux kernel image can now be used with different "initrd"
4581 images; of course this also means that different kernel images can
4582 be run with the same "initrd". This makes testing easier (you don't
4583 have to build a new "zImage.initrd" Linux image when you just
4584 change a file in your "initrd"). Also, a field-upgrade of the
4585 software is easier now.
4591 Porting Linux to U-Boot based systems:
4592 ---------------------------------------
4594 U-Boot cannot save you from doing all the necessary modifications to
4595 configure the Linux device drivers for use with your target hardware
4596 (no, we don't intend to provide a full virtual machine interface to
4599 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4601 Just make sure your machine specific header file (for instance
4602 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4603 Information structure as we define in include/asm-<arch>/u-boot.h,
4604 and make sure that your definition of IMAP_ADDR uses the same value
4605 as your U-Boot configuration in CONFIG_SYS_IMMR.
4608 Configuring the Linux kernel:
4609 -----------------------------
4611 No specific requirements for U-Boot. Make sure you have some root
4612 device (initial ramdisk, NFS) for your target system.
4615 Building a Linux Image:
4616 -----------------------
4618 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4619 not used. If you use recent kernel source, a new build target
4620 "uImage" will exist which automatically builds an image usable by
4621 U-Boot. Most older kernels also have support for a "pImage" target,
4622 which was introduced for our predecessor project PPCBoot and uses a
4623 100% compatible format.
4632 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4633 encapsulate a compressed Linux kernel image with header information,
4634 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4636 * build a standard "vmlinux" kernel image (in ELF binary format):
4638 * convert the kernel into a raw binary image:
4640 ${CROSS_COMPILE}-objcopy -O binary \
4641 -R .note -R .comment \
4642 -S vmlinux linux.bin
4644 * compress the binary image:
4648 * package compressed binary image for U-Boot:
4650 mkimage -A ppc -O linux -T kernel -C gzip \
4651 -a 0 -e 0 -n "Linux Kernel Image" \
4652 -d linux.bin.gz uImage
4655 The "mkimage" tool can also be used to create ramdisk images for use
4656 with U-Boot, either separated from the Linux kernel image, or
4657 combined into one file. "mkimage" encapsulates the images with a 64
4658 byte header containing information about target architecture,
4659 operating system, image type, compression method, entry points, time
4660 stamp, CRC32 checksums, etc.
4662 "mkimage" can be called in two ways: to verify existing images and
4663 print the header information, or to build new images.
4665 In the first form (with "-l" option) mkimage lists the information
4666 contained in the header of an existing U-Boot image; this includes
4667 checksum verification:
4669 tools/mkimage -l image
4670 -l ==> list image header information
4672 The second form (with "-d" option) is used to build a U-Boot image
4673 from a "data file" which is used as image payload:
4675 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4676 -n name -d data_file image
4677 -A ==> set architecture to 'arch'
4678 -O ==> set operating system to 'os'
4679 -T ==> set image type to 'type'
4680 -C ==> set compression type 'comp'
4681 -a ==> set load address to 'addr' (hex)
4682 -e ==> set entry point to 'ep' (hex)
4683 -n ==> set image name to 'name'
4684 -d ==> use image data from 'datafile'
4686 Right now, all Linux kernels for PowerPC systems use the same load
4687 address (0x00000000), but the entry point address depends on the
4690 - 2.2.x kernels have the entry point at 0x0000000C,
4691 - 2.3.x and later kernels have the entry point at 0x00000000.
4693 So a typical call to build a U-Boot image would read:
4695 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4696 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4697 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4698 > examples/uImage.TQM850L
4699 Image Name: 2.4.4 kernel for TQM850L
4700 Created: Wed Jul 19 02:34:59 2000
4701 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4702 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4703 Load Address: 0x00000000
4704 Entry Point: 0x00000000
4706 To verify the contents of the image (or check for corruption):
4708 -> tools/mkimage -l examples/uImage.TQM850L
4709 Image Name: 2.4.4 kernel for TQM850L
4710 Created: Wed Jul 19 02:34:59 2000
4711 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4712 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4713 Load Address: 0x00000000
4714 Entry Point: 0x00000000
4716 NOTE: for embedded systems where boot time is critical you can trade
4717 speed for memory and install an UNCOMPRESSED image instead: this
4718 needs more space in Flash, but boots much faster since it does not
4719 need to be uncompressed:
4721 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4722 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4723 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4724 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4725 > examples/uImage.TQM850L-uncompressed
4726 Image Name: 2.4.4 kernel for TQM850L
4727 Created: Wed Jul 19 02:34:59 2000
4728 Image Type: PowerPC Linux Kernel Image (uncompressed)
4729 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4730 Load Address: 0x00000000
4731 Entry Point: 0x00000000
4734 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4735 when your kernel is intended to use an initial ramdisk:
4737 -> tools/mkimage -n 'Simple Ramdisk Image' \
4738 > -A ppc -O linux -T ramdisk -C gzip \
4739 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4740 Image Name: Simple Ramdisk Image
4741 Created: Wed Jan 12 14:01:50 2000
4742 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4743 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4744 Load Address: 0x00000000
4745 Entry Point: 0x00000000
4748 Installing a Linux Image:
4749 -------------------------
4751 To downloading a U-Boot image over the serial (console) interface,
4752 you must convert the image to S-Record format:
4754 objcopy -I binary -O srec examples/image examples/image.srec
4756 The 'objcopy' does not understand the information in the U-Boot
4757 image header, so the resulting S-Record file will be relative to
4758 address 0x00000000. To load it to a given address, you need to
4759 specify the target address as 'offset' parameter with the 'loads'
4762 Example: install the image to address 0x40100000 (which on the
4763 TQM8xxL is in the first Flash bank):
4765 => erase 40100000 401FFFFF
4771 ## Ready for S-Record download ...
4772 ~>examples/image.srec
4773 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4775 15989 15990 15991 15992
4776 [file transfer complete]
4778 ## Start Addr = 0x00000000
4781 You can check the success of the download using the 'iminfo' command;
4782 this includes a checksum verification so you can be sure no data
4783 corruption happened:
4787 ## Checking Image at 40100000 ...
4788 Image Name: 2.2.13 for initrd on TQM850L
4789 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4790 Data Size: 335725 Bytes = 327 kB = 0 MB
4791 Load Address: 00000000
4792 Entry Point: 0000000c
4793 Verifying Checksum ... OK
4799 The "bootm" command is used to boot an application that is stored in
4800 memory (RAM or Flash). In case of a Linux kernel image, the contents
4801 of the "bootargs" environment variable is passed to the kernel as
4802 parameters. You can check and modify this variable using the
4803 "printenv" and "setenv" commands:
4806 => printenv bootargs
4807 bootargs=root=/dev/ram
4809 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4811 => printenv bootargs
4812 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4815 ## Booting Linux kernel at 40020000 ...
4816 Image Name: 2.2.13 for NFS on TQM850L
4817 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4818 Data Size: 381681 Bytes = 372 kB = 0 MB
4819 Load Address: 00000000
4820 Entry Point: 0000000c
4821 Verifying Checksum ... OK
4822 Uncompressing Kernel Image ... OK
4823 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
4824 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4825 time_init: decrementer frequency = 187500000/60
4826 Calibrating delay loop... 49.77 BogoMIPS
4827 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4830 If you want to boot a Linux kernel with initial RAM disk, you pass
4831 the memory addresses of both the kernel and the initrd image (PPBCOOT
4832 format!) to the "bootm" command:
4834 => imi 40100000 40200000
4836 ## Checking Image at 40100000 ...
4837 Image Name: 2.2.13 for initrd on TQM850L
4838 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4839 Data Size: 335725 Bytes = 327 kB = 0 MB
4840 Load Address: 00000000
4841 Entry Point: 0000000c
4842 Verifying Checksum ... OK
4844 ## Checking Image at 40200000 ...
4845 Image Name: Simple Ramdisk Image
4846 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4847 Data Size: 566530 Bytes = 553 kB = 0 MB
4848 Load Address: 00000000
4849 Entry Point: 00000000
4850 Verifying Checksum ... OK
4852 => bootm 40100000 40200000
4853 ## Booting Linux kernel at 40100000 ...
4854 Image Name: 2.2.13 for initrd on TQM850L
4855 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4856 Data Size: 335725 Bytes = 327 kB = 0 MB
4857 Load Address: 00000000
4858 Entry Point: 0000000c
4859 Verifying Checksum ... OK
4860 Uncompressing Kernel Image ... OK
4861 ## Loading RAMDisk Image at 40200000 ...
4862 Image Name: Simple Ramdisk Image
4863 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4864 Data Size: 566530 Bytes = 553 kB = 0 MB
4865 Load Address: 00000000
4866 Entry Point: 00000000
4867 Verifying Checksum ... OK
4868 Loading Ramdisk ... OK
4869 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
4870 Boot arguments: root=/dev/ram
4871 time_init: decrementer frequency = 187500000/60
4872 Calibrating delay loop... 49.77 BogoMIPS
4874 RAMDISK: Compressed image found at block 0
4875 VFS: Mounted root (ext2 filesystem).
4879 Boot Linux and pass a flat device tree:
4882 First, U-Boot must be compiled with the appropriate defines. See the section
4883 titled "Linux Kernel Interface" above for a more in depth explanation. The
4884 following is an example of how to start a kernel and pass an updated
4890 oft=oftrees/mpc8540ads.dtb
4891 => tftp $oftaddr $oft
4892 Speed: 1000, full duplex
4894 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4895 Filename 'oftrees/mpc8540ads.dtb'.
4896 Load address: 0x300000
4899 Bytes transferred = 4106 (100a hex)
4900 => tftp $loadaddr $bootfile
4901 Speed: 1000, full duplex
4903 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4905 Load address: 0x200000
4906 Loading:############
4908 Bytes transferred = 1029407 (fb51f hex)
4913 => bootm $loadaddr - $oftaddr
4914 ## Booting image at 00200000 ...
4915 Image Name: Linux-2.6.17-dirty
4916 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4917 Data Size: 1029343 Bytes = 1005.2 kB
4918 Load Address: 00000000
4919 Entry Point: 00000000
4920 Verifying Checksum ... OK
4921 Uncompressing Kernel Image ... OK
4922 Booting using flat device tree at 0x300000
4923 Using MPC85xx ADS machine description
4924 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4928 More About U-Boot Image Types:
4929 ------------------------------
4931 U-Boot supports the following image types:
4933 "Standalone Programs" are directly runnable in the environment
4934 provided by U-Boot; it is expected that (if they behave
4935 well) you can continue to work in U-Boot after return from
4936 the Standalone Program.
4937 "OS Kernel Images" are usually images of some Embedded OS which
4938 will take over control completely. Usually these programs
4939 will install their own set of exception handlers, device
4940 drivers, set up the MMU, etc. - this means, that you cannot
4941 expect to re-enter U-Boot except by resetting the CPU.
4942 "RAMDisk Images" are more or less just data blocks, and their
4943 parameters (address, size) are passed to an OS kernel that is
4945 "Multi-File Images" contain several images, typically an OS
4946 (Linux) kernel image and one or more data images like
4947 RAMDisks. This construct is useful for instance when you want
4948 to boot over the network using BOOTP etc., where the boot
4949 server provides just a single image file, but you want to get
4950 for instance an OS kernel and a RAMDisk image.
4952 "Multi-File Images" start with a list of image sizes, each
4953 image size (in bytes) specified by an "uint32_t" in network
4954 byte order. This list is terminated by an "(uint32_t)0".
4955 Immediately after the terminating 0 follow the images, one by
4956 one, all aligned on "uint32_t" boundaries (size rounded up to
4957 a multiple of 4 bytes).
4959 "Firmware Images" are binary images containing firmware (like
4960 U-Boot or FPGA images) which usually will be programmed to
4963 "Script files" are command sequences that will be executed by
4964 U-Boot's command interpreter; this feature is especially
4965 useful when you configure U-Boot to use a real shell (hush)
4966 as command interpreter.
4968 Booting the Linux zImage:
4969 -------------------------
4971 On some platforms, it's possible to boot Linux zImage. This is done
4972 using the "bootz" command. The syntax of "bootz" command is the same
4973 as the syntax of "bootm" command.
4975 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4976 kernel with raw initrd images. The syntax is slightly different, the
4977 address of the initrd must be augmented by it's size, in the following
4978 format: "<initrd addres>:<initrd size>".
4984 One of the features of U-Boot is that you can dynamically load and
4985 run "standalone" applications, which can use some resources of
4986 U-Boot like console I/O functions or interrupt services.
4988 Two simple examples are included with the sources:
4993 'examples/hello_world.c' contains a small "Hello World" Demo
4994 application; it is automatically compiled when you build U-Boot.
4995 It's configured to run at address 0x00040004, so you can play with it
4999 ## Ready for S-Record download ...
5000 ~>examples/hello_world.srec
5001 1 2 3 4 5 6 7 8 9 10 11 ...
5002 [file transfer complete]
5004 ## Start Addr = 0x00040004
5006 => go 40004 Hello World! This is a test.
5007 ## Starting application at 0x00040004 ...
5018 Hit any key to exit ...
5020 ## Application terminated, rc = 0x0
5022 Another example, which demonstrates how to register a CPM interrupt
5023 handler with the U-Boot code, can be found in 'examples/timer.c'.
5024 Here, a CPM timer is set up to generate an interrupt every second.
5025 The interrupt service routine is trivial, just printing a '.'
5026 character, but this is just a demo program. The application can be
5027 controlled by the following keys:
5029 ? - print current values og the CPM Timer registers
5030 b - enable interrupts and start timer
5031 e - stop timer and disable interrupts
5032 q - quit application
5035 ## Ready for S-Record download ...
5036 ~>examples/timer.srec
5037 1 2 3 4 5 6 7 8 9 10 11 ...
5038 [file transfer complete]
5040 ## Start Addr = 0x00040004
5043 ## Starting application at 0x00040004 ...
5046 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5049 [q, b, e, ?] Set interval 1000000 us
5052 [q, b, e, ?] ........
5053 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5056 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5059 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5062 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5064 [q, b, e, ?] ...Stopping timer
5066 [q, b, e, ?] ## Application terminated, rc = 0x0
5072 Over time, many people have reported problems when trying to use the
5073 "minicom" terminal emulation program for serial download. I (wd)
5074 consider minicom to be broken, and recommend not to use it. Under
5075 Unix, I recommend to use C-Kermit for general purpose use (and
5076 especially for kermit binary protocol download ("loadb" command), and
5077 use "cu" for S-Record download ("loads" command). See
5078 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5079 for help with kermit.
5082 Nevertheless, if you absolutely want to use it try adding this
5083 configuration to your "File transfer protocols" section:
5085 Name Program Name U/D FullScr IO-Red. Multi
5086 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5087 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5093 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5094 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5096 Building requires a cross environment; it is known to work on
5097 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5098 need gmake since the Makefiles are not compatible with BSD make).
5099 Note that the cross-powerpc package does not install include files;
5100 attempting to build U-Boot will fail because <machine/ansi.h> is
5101 missing. This file has to be installed and patched manually:
5103 # cd /usr/pkg/cross/powerpc-netbsd/include
5105 # ln -s powerpc machine
5106 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5107 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5109 Native builds *don't* work due to incompatibilities between native
5110 and U-Boot include files.
5112 Booting assumes that (the first part of) the image booted is a
5113 stage-2 loader which in turn loads and then invokes the kernel
5114 proper. Loader sources will eventually appear in the NetBSD source
5115 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5116 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5119 Implementation Internals:
5120 =========================
5122 The following is not intended to be a complete description of every
5123 implementation detail. However, it should help to understand the
5124 inner workings of U-Boot and make it easier to port it to custom
5128 Initial Stack, Global Data:
5129 ---------------------------
5131 The implementation of U-Boot is complicated by the fact that U-Boot
5132 starts running out of ROM (flash memory), usually without access to
5133 system RAM (because the memory controller is not initialized yet).
5134 This means that we don't have writable Data or BSS segments, and BSS
5135 is not initialized as zero. To be able to get a C environment working
5136 at all, we have to allocate at least a minimal stack. Implementation
5137 options for this are defined and restricted by the CPU used: Some CPU
5138 models provide on-chip memory (like the IMMR area on MPC8xx and
5139 MPC826x processors), on others (parts of) the data cache can be
5140 locked as (mis-) used as memory, etc.
5142 Chris Hallinan posted a good summary of these issues to the
5143 U-Boot mailing list:
5145 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5147 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5150 Correct me if I'm wrong, folks, but the way I understand it
5151 is this: Using DCACHE as initial RAM for Stack, etc, does not
5152 require any physical RAM backing up the cache. The cleverness
5153 is that the cache is being used as a temporary supply of
5154 necessary storage before the SDRAM controller is setup. It's
5155 beyond the scope of this list to explain the details, but you
5156 can see how this works by studying the cache architecture and
5157 operation in the architecture and processor-specific manuals.
5159 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5160 is another option for the system designer to use as an
5161 initial stack/RAM area prior to SDRAM being available. Either
5162 option should work for you. Using CS 4 should be fine if your
5163 board designers haven't used it for something that would
5164 cause you grief during the initial boot! It is frequently not
5167 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5168 with your processor/board/system design. The default value
5169 you will find in any recent u-boot distribution in
5170 walnut.h should work for you. I'd set it to a value larger
5171 than your SDRAM module. If you have a 64MB SDRAM module, set
5172 it above 400_0000. Just make sure your board has no resources
5173 that are supposed to respond to that address! That code in
5174 start.S has been around a while and should work as is when
5175 you get the config right.
5180 It is essential to remember this, since it has some impact on the C
5181 code for the initialization procedures:
5183 * Initialized global data (data segment) is read-only. Do not attempt
5186 * Do not use any uninitialized global data (or implicitely initialized
5187 as zero data - BSS segment) at all - this is undefined, initiali-
5188 zation is performed later (when relocating to RAM).
5190 * Stack space is very limited. Avoid big data buffers or things like
5193 Having only the stack as writable memory limits means we cannot use
5194 normal global data to share information beween the code. But it
5195 turned out that the implementation of U-Boot can be greatly
5196 simplified by making a global data structure (gd_t) available to all
5197 functions. We could pass a pointer to this data as argument to _all_
5198 functions, but this would bloat the code. Instead we use a feature of
5199 the GCC compiler (Global Register Variables) to share the data: we
5200 place a pointer (gd) to the global data into a register which we
5201 reserve for this purpose.
5203 When choosing a register for such a purpose we are restricted by the
5204 relevant (E)ABI specifications for the current architecture, and by
5205 GCC's implementation.
5207 For PowerPC, the following registers have specific use:
5209 R2: reserved for system use
5210 R3-R4: parameter passing and return values
5211 R5-R10: parameter passing
5212 R13: small data area pointer
5216 (U-Boot also uses R12 as internal GOT pointer. r12
5217 is a volatile register so r12 needs to be reset when
5218 going back and forth between asm and C)
5220 ==> U-Boot will use R2 to hold a pointer to the global data
5222 Note: on PPC, we could use a static initializer (since the
5223 address of the global data structure is known at compile time),
5224 but it turned out that reserving a register results in somewhat
5225 smaller code - although the code savings are not that big (on
5226 average for all boards 752 bytes for the whole U-Boot image,
5227 624 text + 127 data).
5229 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5230 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5232 ==> U-Boot will use P3 to hold a pointer to the global data
5234 On ARM, the following registers are used:
5236 R0: function argument word/integer result
5237 R1-R3: function argument word
5239 R10: stack limit (used only if stack checking if enabled)
5240 R11: argument (frame) pointer
5241 R12: temporary workspace
5244 R15: program counter
5246 ==> U-Boot will use R8 to hold a pointer to the global data
5248 On Nios II, the ABI is documented here:
5249 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5251 ==> U-Boot will use gp to hold a pointer to the global data
5253 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5254 to access small data sections, so gp is free.
5256 On NDS32, the following registers are used:
5258 R0-R1: argument/return
5260 R15: temporary register for assembler
5261 R16: trampoline register
5262 R28: frame pointer (FP)
5263 R29: global pointer (GP)
5264 R30: link register (LP)
5265 R31: stack pointer (SP)
5266 PC: program counter (PC)
5268 ==> U-Boot will use R10 to hold a pointer to the global data
5270 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5271 or current versions of GCC may "optimize" the code too much.
5276 U-Boot runs in system state and uses physical addresses, i.e. the
5277 MMU is not used either for address mapping nor for memory protection.
5279 The available memory is mapped to fixed addresses using the memory
5280 controller. In this process, a contiguous block is formed for each
5281 memory type (Flash, SDRAM, SRAM), even when it consists of several
5282 physical memory banks.
5284 U-Boot is installed in the first 128 kB of the first Flash bank (on
5285 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5286 booting and sizing and initializing DRAM, the code relocates itself
5287 to the upper end of DRAM. Immediately below the U-Boot code some
5288 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5289 configuration setting]. Below that, a structure with global Board
5290 Info data is placed, followed by the stack (growing downward).
5292 Additionally, some exception handler code is copied to the low 8 kB
5293 of DRAM (0x00000000 ... 0x00001FFF).
5295 So a typical memory configuration with 16 MB of DRAM could look like
5298 0x0000 0000 Exception Vector code
5301 0x0000 2000 Free for Application Use
5307 0x00FB FF20 Monitor Stack (Growing downward)
5308 0x00FB FFAC Board Info Data and permanent copy of global data
5309 0x00FC 0000 Malloc Arena
5312 0x00FE 0000 RAM Copy of Monitor Code
5313 ... eventually: LCD or video framebuffer
5314 ... eventually: pRAM (Protected RAM - unchanged by reset)
5315 0x00FF FFFF [End of RAM]
5318 System Initialization:
5319 ----------------------
5321 In the reset configuration, U-Boot starts at the reset entry point
5322 (on most PowerPC systems at address 0x00000100). Because of the reset
5323 configuration for CS0# this is a mirror of the onboard Flash memory.
5324 To be able to re-map memory U-Boot then jumps to its link address.
5325 To be able to implement the initialization code in C, a (small!)
5326 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5327 which provide such a feature like MPC8xx or MPC8260), or in a locked
5328 part of the data cache. After that, U-Boot initializes the CPU core,
5329 the caches and the SIU.
5331 Next, all (potentially) available memory banks are mapped using a
5332 preliminary mapping. For example, we put them on 512 MB boundaries
5333 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5334 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5335 programmed for SDRAM access. Using the temporary configuration, a
5336 simple memory test is run that determines the size of the SDRAM
5339 When there is more than one SDRAM bank, and the banks are of
5340 different size, the largest is mapped first. For equal size, the first
5341 bank (CS2#) is mapped first. The first mapping is always for address
5342 0x00000000, with any additional banks following immediately to create
5343 contiguous memory starting from 0.
5345 Then, the monitor installs itself at the upper end of the SDRAM area
5346 and allocates memory for use by malloc() and for the global Board
5347 Info data; also, the exception vector code is copied to the low RAM
5348 pages, and the final stack is set up.
5350 Only after this relocation will you have a "normal" C environment;
5351 until that you are restricted in several ways, mostly because you are
5352 running from ROM, and because the code will have to be relocated to a
5356 U-Boot Porting Guide:
5357 ----------------------
5359 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5363 int main(int argc, char *argv[])
5365 sighandler_t no_more_time;
5367 signal(SIGALRM, no_more_time);
5368 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5370 if (available_money > available_manpower) {
5371 Pay consultant to port U-Boot;
5375 Download latest U-Boot source;
5377 Subscribe to u-boot mailing list;
5380 email("Hi, I am new to U-Boot, how do I get started?");
5383 Read the README file in the top level directory;
5384 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5385 Read applicable doc/*.README;
5386 Read the source, Luke;
5387 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5390 if (available_money > toLocalCurrency ($2500))
5393 Add a lot of aggravation and time;
5395 if (a similar board exists) { /* hopefully... */
5396 cp -a board/<similar> board/<myboard>
5397 cp include/configs/<similar>.h include/configs/<myboard>.h
5399 Create your own board support subdirectory;
5400 Create your own board include/configs/<myboard>.h file;
5402 Edit new board/<myboard> files
5403 Edit new include/configs/<myboard>.h
5408 Add / modify source code;
5412 email("Hi, I am having problems...");
5414 Send patch file to the U-Boot email list;
5415 if (reasonable critiques)
5416 Incorporate improvements from email list code review;
5418 Defend code as written;
5424 void no_more_time (int sig)
5433 All contributions to U-Boot should conform to the Linux kernel
5434 coding style; see the file "Documentation/CodingStyle" and the script
5435 "scripts/Lindent" in your Linux kernel source directory.
5437 Source files originating from a different project (for example the
5438 MTD subsystem) are generally exempt from these guidelines and are not
5439 reformated to ease subsequent migration to newer versions of those
5442 Please note that U-Boot is implemented in C (and to some small parts in
5443 Assembler); no C++ is used, so please do not use C++ style comments (//)
5446 Please also stick to the following formatting rules:
5447 - remove any trailing white space
5448 - use TAB characters for indentation and vertical alignment, not spaces
5449 - make sure NOT to use DOS '\r\n' line feeds
5450 - do not add more than 2 consecutive empty lines to source files
5451 - do not add trailing empty lines to source files
5453 Submissions which do not conform to the standards may be returned
5454 with a request to reformat the changes.
5460 Since the number of patches for U-Boot is growing, we need to
5461 establish some rules. Submissions which do not conform to these rules
5462 may be rejected, even when they contain important and valuable stuff.
5464 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5467 see http://lists.denx.de/mailman/listinfo/u-boot
5469 When you send a patch, please include the following information with
5472 * For bug fixes: a description of the bug and how your patch fixes
5473 this bug. Please try to include a way of demonstrating that the
5474 patch actually fixes something.
5476 * For new features: a description of the feature and your
5479 * A CHANGELOG entry as plaintext (separate from the patch)
5481 * For major contributions, your entry to the CREDITS file
5483 * When you add support for a new board, don't forget to add this
5484 board to the MAINTAINERS file, too.
5486 * If your patch adds new configuration options, don't forget to
5487 document these in the README file.
5489 * The patch itself. If you are using git (which is *strongly*
5490 recommended) you can easily generate the patch using the
5491 "git format-patch". If you then use "git send-email" to send it to
5492 the U-Boot mailing list, you will avoid most of the common problems
5493 with some other mail clients.
5495 If you cannot use git, use "diff -purN OLD NEW". If your version of
5496 diff does not support these options, then get the latest version of
5499 The current directory when running this command shall be the parent
5500 directory of the U-Boot source tree (i. e. please make sure that
5501 your patch includes sufficient directory information for the
5504 We prefer patches as plain text. MIME attachments are discouraged,
5505 and compressed attachments must not be used.
5507 * If one logical set of modifications affects or creates several
5508 files, all these changes shall be submitted in a SINGLE patch file.
5510 * Changesets that contain different, unrelated modifications shall be
5511 submitted as SEPARATE patches, one patch per changeset.
5516 * Before sending the patch, run the MAKEALL script on your patched
5517 source tree and make sure that no errors or warnings are reported
5518 for any of the boards.
5520 * Keep your modifications to the necessary minimum: A patch
5521 containing several unrelated changes or arbitrary reformats will be
5522 returned with a request to re-formatting / split it.
5524 * If you modify existing code, make sure that your new code does not
5525 add to the memory footprint of the code ;-) Small is beautiful!
5526 When adding new features, these should compile conditionally only
5527 (using #ifdef), and the resulting code with the new feature
5528 disabled must not need more memory than the old code without your
5531 * Remember that there is a size limit of 100 kB per message on the
5532 u-boot mailing list. Bigger patches will be moderated. If they are
5533 reasonable and not too big, they will be acknowledged. But patches
5534 bigger than the size limit should be avoided.
projects / J-u-boot.git / blob