2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /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_742230
489 CONFIG_ARM_ERRATA_743622
490 CONFIG_ARM_ERRATA_751472
492 If set, the workarounds for these ARM errata are applied early
493 during U-Boot startup. Note that these options force the
494 workarounds to be applied; no CPU-type/version detection
495 exists, unlike the similar options in the Linux kernel. Do not
496 set these options unless they apply!
498 - Linux Kernel Interface:
501 U-Boot stores all clock information in Hz
502 internally. For binary compatibility with older Linux
503 kernels (which expect the clocks passed in the
504 bd_info data to be in MHz) the environment variable
505 "clocks_in_mhz" can be defined so that U-Boot
506 converts clock data to MHZ before passing it to the
508 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
509 "clocks_in_mhz=1" is automatically included in the
512 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
514 When transferring memsize parameter to linux, some versions
515 expect it to be in bytes, others in MB.
516 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
520 New kernel versions are expecting firmware settings to be
521 passed using flattened device trees (based on open firmware
525 * New libfdt-based support
526 * Adds the "fdt" command
527 * The bootm command automatically updates the fdt
529 OF_CPU - The proper name of the cpus node (only required for
530 MPC512X and MPC5xxx based boards).
531 OF_SOC - The proper name of the soc node (only required for
532 MPC512X and MPC5xxx based boards).
533 OF_TBCLK - The timebase frequency.
534 OF_STDOUT_PATH - The path to the console device
536 boards with QUICC Engines require OF_QE to set UCC MAC
539 CONFIG_OF_BOARD_SETUP
541 Board code has addition modification that it wants to make
542 to the flat device tree before handing it off to the kernel
546 This define fills in the correct boot CPU in the boot
547 param header, the default value is zero if undefined.
551 U-Boot can detect if an IDE device is present or not.
552 If not, and this new config option is activated, U-Boot
553 removes the ATA node from the DTS before booting Linux,
554 so the Linux IDE driver does not probe the device and
555 crash. This is needed for buggy hardware (uc101) where
556 no pull down resistor is connected to the signal IDE5V_DD7.
558 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
560 This setting is mandatory for all boards that have only one
561 machine type and must be used to specify the machine type
562 number as it appears in the ARM machine registry
563 (see http://www.arm.linux.org.uk/developer/machines/).
564 Only boards that have multiple machine types supported
565 in a single configuration file and the machine type is
566 runtime discoverable, do not have to use this setting.
568 - vxWorks boot parameters:
570 bootvx constructs a valid bootline using the following
571 environments variables: bootfile, ipaddr, serverip, hostname.
572 It loads the vxWorks image pointed bootfile.
574 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
575 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
576 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
577 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
579 CONFIG_SYS_VXWORKS_ADD_PARAMS
581 Add it at the end of the bootline. E.g "u=username pw=secret"
583 Note: If a "bootargs" environment is defined, it will overwride
584 the defaults discussed just above.
586 - Cache Configuration:
587 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
588 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
589 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
591 - Cache Configuration for ARM:
592 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
594 CONFIG_SYS_PL310_BASE - Physical base address of PL310
595 controller register space
600 Define this if you want support for Amba PrimeCell PL010 UARTs.
604 Define this if you want support for Amba PrimeCell PL011 UARTs.
608 If you have Amba PrimeCell PL011 UARTs, set this variable to
609 the clock speed of the UARTs.
613 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
614 define this to a list of base addresses for each (supported)
615 port. See e.g. include/configs/versatile.h
617 CONFIG_PL011_SERIAL_RLCR
619 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
620 have separate receive and transmit line control registers. Set
621 this variable to initialize the extra register.
623 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
625 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
626 boot loader that has already initialized the UART. Define this
627 variable to flush the UART at init time.
629 CONFIG_SYS_NS16550_BROKEN_TEMT
631 16550 UART set the Transmitter Empty (TEMT) Bit when all output
632 has finished and the transmitter is totally empty. U-Boot waits
633 for this bit to be set to initialize the serial console. On some
634 broken platforms this bit is not set in SPL making U-Boot to
635 hang while waiting for TEMT. Define this option to avoid it.
639 Depending on board, define exactly one serial port
640 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
641 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
642 console by defining CONFIG_8xx_CONS_NONE
644 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
645 port routines must be defined elsewhere
646 (i.e. serial_init(), serial_getc(), ...)
649 Enables console device for a color framebuffer. Needs following
650 defines (cf. smiLynxEM, i8042)
651 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
653 VIDEO_HW_RECTFILL graphic chip supports
656 VIDEO_HW_BITBLT graphic chip supports
657 bit-blit (cf. smiLynxEM)
658 VIDEO_VISIBLE_COLS visible pixel columns
660 VIDEO_VISIBLE_ROWS visible pixel rows
661 VIDEO_PIXEL_SIZE bytes per pixel
662 VIDEO_DATA_FORMAT graphic data format
663 (0-5, cf. cfb_console.c)
664 VIDEO_FB_ADRS framebuffer address
665 VIDEO_KBD_INIT_FCT keyboard int fct
666 (i.e. i8042_kbd_init())
667 VIDEO_TSTC_FCT test char fct
669 VIDEO_GETC_FCT get char fct
671 CONFIG_CONSOLE_CURSOR cursor drawing on/off
672 (requires blink timer
674 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
675 CONFIG_CONSOLE_TIME display time/date info in
677 (requires CONFIG_CMD_DATE)
678 CONFIG_VIDEO_LOGO display Linux logo in
680 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
681 linux_logo.h for logo.
682 Requires CONFIG_VIDEO_LOGO
683 CONFIG_CONSOLE_EXTRA_INFO
684 additional board info beside
687 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
688 a limited number of ANSI escape sequences (cursor control,
689 erase functions and limited graphics rendition control).
691 When CONFIG_CFB_CONSOLE is defined, video console is
692 default i/o. Serial console can be forced with
693 environment 'console=serial'.
695 When CONFIG_SILENT_CONSOLE is defined, all console
696 messages (by U-Boot and Linux!) can be silenced with
697 the "silent" environment variable. See
698 doc/README.silent for more information.
701 CONFIG_BAUDRATE - in bps
702 Select one of the baudrates listed in
703 CONFIG_SYS_BAUDRATE_TABLE, see below.
704 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
706 - Console Rx buffer length
707 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
708 the maximum receive buffer length for the SMC.
709 This option is actual only for 82xx and 8xx possible.
710 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
711 must be defined, to setup the maximum idle timeout for
714 - Pre-Console Buffer:
715 Prior to the console being initialised (i.e. serial UART
716 initialised etc) all console output is silently discarded.
717 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
718 buffer any console messages prior to the console being
719 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
720 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
721 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
722 bytes are output before the console is initialised, the
723 earlier bytes are discarded.
725 'Sane' compilers will generate smaller code if
726 CONFIG_PRE_CON_BUF_SZ is a power of 2
728 - Safe printf() functions
729 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
730 the printf() functions. These are defined in
731 include/vsprintf.h and include snprintf(), vsnprintf() and
732 so on. Code size increase is approximately 300-500 bytes.
733 If this option is not given then these functions will
734 silently discard their buffer size argument - this means
735 you are not getting any overflow checking in this case.
737 - Boot Delay: CONFIG_BOOTDELAY - in seconds
738 Delay before automatically booting the default image;
739 set to -1 to disable autoboot.
740 set to -2 to autoboot with no delay and not check for abort
741 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
743 See doc/README.autoboot for these options that
744 work with CONFIG_BOOTDELAY. None are required.
745 CONFIG_BOOT_RETRY_TIME
746 CONFIG_BOOT_RETRY_MIN
747 CONFIG_AUTOBOOT_KEYED
748 CONFIG_AUTOBOOT_PROMPT
749 CONFIG_AUTOBOOT_DELAY_STR
750 CONFIG_AUTOBOOT_STOP_STR
751 CONFIG_AUTOBOOT_DELAY_STR2
752 CONFIG_AUTOBOOT_STOP_STR2
753 CONFIG_ZERO_BOOTDELAY_CHECK
754 CONFIG_RESET_TO_RETRY
758 Only needed when CONFIG_BOOTDELAY is enabled;
759 define a command string that is automatically executed
760 when no character is read on the console interface
761 within "Boot Delay" after reset.
764 This can be used to pass arguments to the bootm
765 command. The value of CONFIG_BOOTARGS goes into the
766 environment value "bootargs".
768 CONFIG_RAMBOOT and CONFIG_NFSBOOT
769 The value of these goes into the environment as
770 "ramboot" and "nfsboot" respectively, and can be used
771 as a convenience, when switching between booting from
777 When this option is #defined, the existence of the
778 environment variable "preboot" will be checked
779 immediately before starting the CONFIG_BOOTDELAY
780 countdown and/or running the auto-boot command resp.
781 entering interactive mode.
783 This feature is especially useful when "preboot" is
784 automatically generated or modified. For an example
785 see the LWMON board specific code: here "preboot" is
786 modified when the user holds down a certain
787 combination of keys on the (special) keyboard when
790 - Serial Download Echo Mode:
792 If defined to 1, all characters received during a
793 serial download (using the "loads" command) are
794 echoed back. This might be needed by some terminal
795 emulations (like "cu"), but may as well just take
796 time on others. This setting #define's the initial
797 value of the "loads_echo" environment variable.
799 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
801 Select one of the baudrates listed in
802 CONFIG_SYS_BAUDRATE_TABLE, see below.
805 Monitor commands can be included or excluded
806 from the build by using the #include files
807 <config_cmd_all.h> and #undef'ing unwanted
808 commands, or using <config_cmd_default.h>
809 and augmenting with additional #define's
812 The default command configuration includes all commands
813 except those marked below with a "*".
815 CONFIG_CMD_ASKENV * ask for env variable
816 CONFIG_CMD_BDI bdinfo
817 CONFIG_CMD_BEDBUG * Include BedBug Debugger
818 CONFIG_CMD_BMP * BMP support
819 CONFIG_CMD_BSP * Board specific commands
820 CONFIG_CMD_BOOTD bootd
821 CONFIG_CMD_CACHE * icache, dcache
822 CONFIG_CMD_CONSOLE coninfo
823 CONFIG_CMD_CRC32 * crc32
824 CONFIG_CMD_DATE * support for RTC, date/time...
825 CONFIG_CMD_DHCP * DHCP support
826 CONFIG_CMD_DIAG * Diagnostics
827 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
828 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
829 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
830 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
831 CONFIG_CMD_DTT * Digital Therm and Thermostat
832 CONFIG_CMD_ECHO echo arguments
833 CONFIG_CMD_EDITENV edit env variable
834 CONFIG_CMD_EEPROM * EEPROM read/write support
835 CONFIG_CMD_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
837 CONFIG_CMD_ENV_FLAGS * display details about env flags
838 CONFIG_CMD_EXPORTENV * export the environment
839 CONFIG_CMD_EXT2 * ext2 command support
840 CONFIG_CMD_EXT4 * ext4 command support
841 CONFIG_CMD_SAVEENV saveenv
842 CONFIG_CMD_FDC * Floppy Disk Support
843 CONFIG_CMD_FAT * FAT command support
844 CONFIG_CMD_FDOS * Dos diskette Support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GETTIME * Get time since boot
848 CONFIG_CMD_GO * the 'go' command (exec code)
849 CONFIG_CMD_GREPENV * search environment
850 CONFIG_CMD_HASH * calculate hash / digest
851 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
852 CONFIG_CMD_I2C * I2C serial bus support
853 CONFIG_CMD_IDE * IDE harddisk support
854 CONFIG_CMD_IMI iminfo
855 CONFIG_CMD_IMLS List all images found in NOR flash
856 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
857 CONFIG_CMD_IMMAP * IMMR dump support
858 CONFIG_CMD_IMPORTENV * import an environment
859 CONFIG_CMD_INI * import data from an ini file into the env
860 CONFIG_CMD_IRQ * irqinfo
861 CONFIG_CMD_ITEST Integer/string test of 2 values
862 CONFIG_CMD_JFFS2 * JFFS2 Support
863 CONFIG_CMD_KGDB * kgdb
864 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
865 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
867 CONFIG_CMD_LOADB loadb
868 CONFIG_CMD_LOADS loads
869 CONFIG_CMD_MD5SUM print md5 message digest
870 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
871 CONFIG_CMD_MEMINFO * Display detailed memory information
872 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
874 CONFIG_CMD_MISC Misc functions like sleep etc
875 CONFIG_CMD_MMC * MMC memory mapped support
876 CONFIG_CMD_MII * MII utility commands
877 CONFIG_CMD_MTDPARTS * MTD partition support
878 CONFIG_CMD_NAND * NAND support
879 CONFIG_CMD_NET bootp, tftpboot, rarpboot
880 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
881 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
882 CONFIG_CMD_PCI * pciinfo
883 CONFIG_CMD_PCMCIA * PCMCIA support
884 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
886 CONFIG_CMD_PORTIO * Port I/O
887 CONFIG_CMD_READ * Read raw data from partition
888 CONFIG_CMD_REGINFO * Register dump
889 CONFIG_CMD_RUN run command in env variable
890 CONFIG_CMD_SANDBOX * sb command to access sandbox features
891 CONFIG_CMD_SAVES * save S record dump
892 CONFIG_CMD_SCSI * SCSI Support
893 CONFIG_CMD_SDRAM * print SDRAM configuration information
894 (requires CONFIG_CMD_I2C)
895 CONFIG_CMD_SETGETDCR Support for DCR Register access
897 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
898 CONFIG_CMD_SHA1SUM print sha1 memory digest
899 (requires CONFIG_CMD_MEMORY)
900 CONFIG_CMD_SOURCE "source" command Support
901 CONFIG_CMD_SPI * SPI serial bus support
902 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
903 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
904 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
905 CONFIG_CMD_TIMER * access to the system tick timer
906 CONFIG_CMD_USB * USB support
907 CONFIG_CMD_CDP * Cisco Discover Protocol support
908 CONFIG_CMD_MFSL * Microblaze FSL support
911 EXAMPLE: If you want all functions except of network
912 support you can write:
914 #include "config_cmd_all.h"
915 #undef CONFIG_CMD_NET
918 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
920 Note: Don't enable the "icache" and "dcache" commands
921 (configuration option CONFIG_CMD_CACHE) unless you know
922 what you (and your U-Boot users) are doing. Data
923 cache cannot be enabled on systems like the 8xx or
924 8260 (where accesses to the IMMR region must be
925 uncached), and it cannot be disabled on all other
926 systems where we (mis-) use the data cache to hold an
927 initial stack and some data.
930 XXX - this list needs to get updated!
934 If this variable is defined, U-Boot will use a device tree
935 to configure its devices, instead of relying on statically
936 compiled #defines in the board file. This option is
937 experimental and only available on a few boards. The device
938 tree is available in the global data as gd->fdt_blob.
940 U-Boot needs to get its device tree from somewhere. This can
941 be done using one of the two options below:
944 If this variable is defined, U-Boot will embed a device tree
945 binary in its image. This device tree file should be in the
946 board directory and called <soc>-<board>.dts. The binary file
947 is then picked up in board_init_f() and made available through
948 the global data structure as gd->blob.
951 If this variable is defined, U-Boot will build a device tree
952 binary. It will be called u-boot.dtb. Architecture-specific
953 code will locate it at run-time. Generally this works by:
955 cat u-boot.bin u-boot.dtb >image.bin
957 and in fact, U-Boot does this for you, creating a file called
958 u-boot-dtb.bin which is useful in the common case. You can
959 still use the individual files if you need something more
964 If this variable is defined, it enables watchdog
965 support for the SoC. There must be support in the SoC
966 specific code for a watchdog. For the 8xx and 8260
967 CPUs, the SIU Watchdog feature is enabled in the SYPCR
968 register. When supported for a specific SoC is
969 available, then no further board specific code should
973 When using a watchdog circuitry external to the used
974 SoC, then define this variable and provide board
975 specific code for the "hw_watchdog_reset" function.
978 CONFIG_VERSION_VARIABLE
979 If this variable is defined, an environment variable
980 named "ver" is created by U-Boot showing the U-Boot
981 version as printed by the "version" command.
982 Any change to this variable will be reverted at the
987 When CONFIG_CMD_DATE is selected, the type of the RTC
988 has to be selected, too. Define exactly one of the
991 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
992 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
993 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
994 CONFIG_RTC_MC146818 - use MC146818 RTC
995 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
996 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
997 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
998 CONFIG_RTC_DS164x - use Dallas DS164x RTC
999 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1000 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1001 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1002 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1005 Note that if the RTC uses I2C, then the I2C interface
1006 must also be configured. See I2C Support, below.
1009 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1010 CONFIG_PCA953X_INFO - enable pca953x info command
1012 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1013 chip-ngpio pairs that tell the PCA953X driver the number of
1014 pins supported by a particular chip.
1016 Note that if the GPIO device uses I2C, then the I2C interface
1017 must also be configured. See I2C Support, below.
1019 - Timestamp Support:
1021 When CONFIG_TIMESTAMP is selected, the timestamp
1022 (date and time) of an image is printed by image
1023 commands like bootm or iminfo. This option is
1024 automatically enabled when you select CONFIG_CMD_DATE .
1026 - Partition Labels (disklabels) Supported:
1027 Zero or more of the following:
1028 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1029 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1030 Intel architecture, USB sticks, etc.
1031 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1032 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1033 bootloader. Note 2TB partition limit; see
1035 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1037 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1038 CONFIG_CMD_SCSI) you must configure support for at
1039 least one non-MTD partition type as well.
1042 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1043 board configurations files but used nowhere!
1045 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1046 be performed by calling the function
1047 ide_set_reset(int reset)
1048 which has to be defined in a board specific file
1053 Set this to enable ATAPI support.
1058 Set this to enable support for disks larger than 137GB
1059 Also look at CONFIG_SYS_64BIT_LBA.
1060 Whithout these , LBA48 support uses 32bit variables and will 'only'
1061 support disks up to 2.1TB.
1063 CONFIG_SYS_64BIT_LBA:
1064 When enabled, makes the IDE subsystem use 64bit sector addresses.
1068 At the moment only there is only support for the
1069 SYM53C8XX SCSI controller; define
1070 CONFIG_SCSI_SYM53C8XX to enable it.
1072 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1073 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1074 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1075 maximum numbers of LUNs, SCSI ID's and target
1077 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1079 The environment variable 'scsidevs' is set to the number of
1080 SCSI devices found during the last scan.
1082 - NETWORK Support (PCI):
1084 Support for Intel 8254x/8257x gigabit chips.
1087 Utility code for direct access to the SPI bus on Intel 8257x.
1088 This does not do anything useful unless you set at least one
1089 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1091 CONFIG_E1000_SPI_GENERIC
1092 Allow generic access to the SPI bus on the Intel 8257x, for
1093 example with the "sspi" command.
1096 Management command for E1000 devices. When used on devices
1097 with SPI support you can reprogram the EEPROM from U-Boot.
1099 CONFIG_E1000_FALLBACK_MAC
1100 default MAC for empty EEPROM after production.
1103 Support for Intel 82557/82559/82559ER chips.
1104 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1105 write routine for first time initialisation.
1108 Support for Digital 2114x chips.
1109 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1110 modem chip initialisation (KS8761/QS6611).
1113 Support for National dp83815 chips.
1116 Support for National dp8382[01] gigabit chips.
1118 - NETWORK Support (other):
1120 CONFIG_DRIVER_AT91EMAC
1121 Support for AT91RM9200 EMAC.
1124 Define this to use reduced MII inteface
1126 CONFIG_DRIVER_AT91EMAC_QUIET
1127 If this defined, the driver is quiet.
1128 The driver doen't show link status messages.
1130 CONFIG_CALXEDA_XGMAC
1131 Support for the Calxeda XGMAC device
1134 Support for SMSC's LAN91C96 chips.
1136 CONFIG_LAN91C96_BASE
1137 Define this to hold the physical address
1138 of the LAN91C96's I/O space
1140 CONFIG_LAN91C96_USE_32_BIT
1141 Define this to enable 32 bit addressing
1144 Support for SMSC's LAN91C111 chip
1146 CONFIG_SMC91111_BASE
1147 Define this to hold the physical address
1148 of the device (I/O space)
1150 CONFIG_SMC_USE_32_BIT
1151 Define this if data bus is 32 bits
1153 CONFIG_SMC_USE_IOFUNCS
1154 Define this to use i/o functions instead of macros
1155 (some hardware wont work with macros)
1157 CONFIG_DRIVER_TI_EMAC
1158 Support for davinci emac
1160 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1161 Define this if you have more then 3 PHYs.
1164 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1166 CONFIG_FTGMAC100_EGIGA
1167 Define this to use GE link update with gigabit PHY.
1168 Define this if FTGMAC100 is connected to gigabit PHY.
1169 If your system has 10/100 PHY only, it might not occur
1170 wrong behavior. Because PHY usually return timeout or
1171 useless data when polling gigabit status and gigabit
1172 control registers. This behavior won't affect the
1173 correctnessof 10/100 link speed update.
1176 Support for SMSC's LAN911x and LAN921x chips
1179 Define this to hold the physical address
1180 of the device (I/O space)
1182 CONFIG_SMC911X_32_BIT
1183 Define this if data bus is 32 bits
1185 CONFIG_SMC911X_16_BIT
1186 Define this if data bus is 16 bits. If your processor
1187 automatically converts one 32 bit word to two 16 bit
1188 words you may also try CONFIG_SMC911X_32_BIT.
1191 Support for Renesas on-chip Ethernet controller
1193 CONFIG_SH_ETHER_USE_PORT
1194 Define the number of ports to be used
1196 CONFIG_SH_ETHER_PHY_ADDR
1197 Define the ETH PHY's address
1199 CONFIG_SH_ETHER_CACHE_WRITEBACK
1200 If this option is set, the driver enables cache flush.
1203 CONFIG_GENERIC_LPC_TPM
1204 Support for generic parallel port TPM devices. Only one device
1205 per system is supported at this time.
1207 CONFIG_TPM_TIS_BASE_ADDRESS
1208 Base address where the generic TPM device is mapped
1209 to. Contemporary x86 systems usually map it at
1213 At the moment only the UHCI host controller is
1214 supported (PIP405, MIP405, MPC5200); define
1215 CONFIG_USB_UHCI to enable it.
1216 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1217 and define CONFIG_USB_STORAGE to enable the USB
1220 Supported are USB Keyboards and USB Floppy drives
1222 MPC5200 USB requires additional defines:
1224 for 528 MHz Clock: 0x0001bbbb
1228 for differential drivers: 0x00001000
1229 for single ended drivers: 0x00005000
1230 for differential drivers on PSC3: 0x00000100
1231 for single ended drivers on PSC3: 0x00004100
1232 CONFIG_SYS_USB_EVENT_POLL
1233 May be defined to allow interrupt polling
1234 instead of using asynchronous interrupts
1236 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1237 txfilltuning field in the EHCI controller on reset.
1240 Define the below if you wish to use the USB console.
1241 Once firmware is rebuilt from a serial console issue the
1242 command "setenv stdin usbtty; setenv stdout usbtty" and
1243 attach your USB cable. The Unix command "dmesg" should print
1244 it has found a new device. The environment variable usbtty
1245 can be set to gserial or cdc_acm to enable your device to
1246 appear to a USB host as a Linux gserial device or a
1247 Common Device Class Abstract Control Model serial device.
1248 If you select usbtty = gserial you should be able to enumerate
1250 # modprobe usbserial vendor=0xVendorID product=0xProductID
1251 else if using cdc_acm, simply setting the environment
1252 variable usbtty to be cdc_acm should suffice. The following
1253 might be defined in YourBoardName.h
1256 Define this to build a UDC device
1259 Define this to have a tty type of device available to
1260 talk to the UDC device
1263 Define this to enable the high speed support for usb
1264 device and usbtty. If this feature is enabled, a routine
1265 int is_usbd_high_speed(void)
1266 also needs to be defined by the driver to dynamically poll
1267 whether the enumeration has succeded at high speed or full
1270 CONFIG_SYS_CONSOLE_IS_IN_ENV
1271 Define this if you want stdin, stdout &/or stderr to
1275 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1276 Derive USB clock from external clock "blah"
1277 - CONFIG_SYS_USB_EXTC_CLK 0x02
1279 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1280 Derive USB clock from brgclk
1281 - CONFIG_SYS_USB_BRG_CLK 0x04
1283 If you have a USB-IF assigned VendorID then you may wish to
1284 define your own vendor specific values either in BoardName.h
1285 or directly in usbd_vendor_info.h. If you don't define
1286 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1287 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1288 should pretend to be a Linux device to it's target host.
1290 CONFIG_USBD_MANUFACTURER
1291 Define this string as the name of your company for
1292 - CONFIG_USBD_MANUFACTURER "my company"
1294 CONFIG_USBD_PRODUCT_NAME
1295 Define this string as the name of your product
1296 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1298 CONFIG_USBD_VENDORID
1299 Define this as your assigned Vendor ID from the USB
1300 Implementors Forum. This *must* be a genuine Vendor ID
1301 to avoid polluting the USB namespace.
1302 - CONFIG_USBD_VENDORID 0xFFFF
1304 CONFIG_USBD_PRODUCTID
1305 Define this as the unique Product ID
1307 - CONFIG_USBD_PRODUCTID 0xFFFF
1309 - ULPI Layer Support:
1310 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1311 the generic ULPI layer. The generic layer accesses the ULPI PHY
1312 via the platform viewport, so you need both the genric layer and
1313 the viewport enabled. Currently only Chipidea/ARC based
1314 viewport is supported.
1315 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1316 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1317 If your ULPI phy needs a different reference clock than the
1318 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1319 the appropriate value in Hz.
1322 The MMC controller on the Intel PXA is supported. To
1323 enable this define CONFIG_MMC. The MMC can be
1324 accessed from the boot prompt by mapping the device
1325 to physical memory similar to flash. Command line is
1326 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1327 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1330 Support for Renesas on-chip MMCIF controller
1332 CONFIG_SH_MMCIF_ADDR
1333 Define the base address of MMCIF registers
1336 Define the clock frequency for MMCIF
1338 - Journaling Flash filesystem support:
1339 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1340 CONFIG_JFFS2_NAND_DEV
1341 Define these for a default partition on a NAND device
1343 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1344 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1345 Define these for a default partition on a NOR device
1347 CONFIG_SYS_JFFS_CUSTOM_PART
1348 Define this to create an own partition. You have to provide a
1349 function struct part_info* jffs2_part_info(int part_num)
1351 If you define only one JFFS2 partition you may also want to
1352 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1353 to disable the command chpart. This is the default when you
1354 have not defined a custom partition
1356 - FAT(File Allocation Table) filesystem write function support:
1359 Define this to enable support for saving memory data as a
1360 file in FAT formatted partition.
1362 This will also enable the command "fatwrite" enabling the
1363 user to write files to FAT.
1365 CBFS (Coreboot Filesystem) support
1368 Define this to enable support for reading from a Coreboot
1369 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1375 Define this to enable standard (PC-Style) keyboard
1379 Standard PC keyboard driver with US (is default) and
1380 GERMAN key layout (switch via environment 'keymap=de') support.
1381 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1382 for cfb_console. Supports cursor blinking.
1387 Define this to enable video support (for output to
1390 CONFIG_VIDEO_CT69000
1392 Enable Chips & Technologies 69000 Video chip
1394 CONFIG_VIDEO_SMI_LYNXEM
1395 Enable Silicon Motion SMI 712/710/810 Video chip. The
1396 video output is selected via environment 'videoout'
1397 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1400 For the CT69000 and SMI_LYNXEM drivers, videomode is
1401 selected via environment 'videomode'. Two different ways
1403 - "videomode=num" 'num' is a standard LiLo mode numbers.
1404 Following standard modes are supported (* is default):
1406 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1407 -------------+---------------------------------------------
1408 8 bits | 0x301* 0x303 0x305 0x161 0x307
1409 15 bits | 0x310 0x313 0x316 0x162 0x319
1410 16 bits | 0x311 0x314 0x317 0x163 0x31A
1411 24 bits | 0x312 0x315 0x318 ? 0x31B
1412 -------------+---------------------------------------------
1413 (i.e. setenv videomode 317; saveenv; reset;)
1415 - "videomode=bootargs" all the video parameters are parsed
1416 from the bootargs. (See drivers/video/videomodes.c)
1419 CONFIG_VIDEO_SED13806
1420 Enable Epson SED13806 driver. This driver supports 8bpp
1421 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1422 or CONFIG_VIDEO_SED13806_16BPP
1425 Enable the Freescale DIU video driver. Reference boards for
1426 SOCs that have a DIU should define this macro to enable DIU
1427 support, and should also define these other macros:
1433 CONFIG_VIDEO_SW_CURSOR
1434 CONFIG_VGA_AS_SINGLE_DEVICE
1436 CONFIG_VIDEO_BMP_LOGO
1438 The DIU driver will look for the 'video-mode' environment
1439 variable, and if defined, enable the DIU as a console during
1440 boot. See the documentation file README.video for a
1441 description of this variable.
1445 Enable the VGA video / BIOS for x86. The alternative if you
1446 are using coreboot is to use the coreboot frame buffer
1453 Define this to enable a custom keyboard support.
1454 This simply calls drv_keyboard_init() which must be
1455 defined in your board-specific files.
1456 The only board using this so far is RBC823.
1458 - LCD Support: CONFIG_LCD
1460 Define this to enable LCD support (for output to LCD
1461 display); also select one of the supported displays
1462 by defining one of these:
1466 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1468 CONFIG_NEC_NL6448AC33:
1470 NEC NL6448AC33-18. Active, color, single scan.
1472 CONFIG_NEC_NL6448BC20
1474 NEC NL6448BC20-08. 6.5", 640x480.
1475 Active, color, single scan.
1477 CONFIG_NEC_NL6448BC33_54
1479 NEC NL6448BC33-54. 10.4", 640x480.
1480 Active, color, single scan.
1484 Sharp 320x240. Active, color, single scan.
1485 It isn't 16x9, and I am not sure what it is.
1487 CONFIG_SHARP_LQ64D341
1489 Sharp LQ64D341 display, 640x480.
1490 Active, color, single scan.
1494 HLD1045 display, 640x480.
1495 Active, color, single scan.
1499 Optrex CBL50840-2 NF-FW 99 22 M5
1501 Hitachi LMG6912RPFC-00T
1505 320x240. Black & white.
1507 Normally display is black on white background; define
1508 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1510 CONFIG_LCD_ALIGNMENT
1512 Normally the LCD is page-aligned (tyically 4KB). If this is
1513 defined then the LCD will be aligned to this value instead.
1514 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1515 here, since it is cheaper to change data cache settings on
1516 a per-section basis.
1518 CONFIG_CONSOLE_SCROLL_LINES
1520 When the console need to be scrolled, this is the number of
1521 lines to scroll by. It defaults to 1. Increasing this makes
1522 the console jump but can help speed up operation when scrolling
1527 Support drawing of RLE8-compressed bitmaps on the LCD.
1531 Enables an 'i2c edid' command which can read EDID
1532 information over I2C from an attached LCD display.
1534 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1536 If this option is set, the environment is checked for
1537 a variable "splashimage". If found, the usual display
1538 of logo, copyright and system information on the LCD
1539 is suppressed and the BMP image at the address
1540 specified in "splashimage" is loaded instead. The
1541 console is redirected to the "nulldev", too. This
1542 allows for a "silent" boot where a splash screen is
1543 loaded very quickly after power-on.
1545 CONFIG_SPLASHIMAGE_GUARD
1547 If this option is set, then U-Boot will prevent the environment
1548 variable "splashimage" from being set to a problematic address
1549 (see README.displaying-bmps and README.arm-unaligned-accesses).
1550 This option is useful for targets where, due to alignment
1551 restrictions, an improperly aligned BMP image will cause a data
1552 abort. If you think you will not have problems with unaligned
1553 accesses (for example because your toolchain prevents them)
1554 there is no need to set this option.
1556 CONFIG_SPLASH_SCREEN_ALIGN
1558 If this option is set the splash image can be freely positioned
1559 on the screen. Environment variable "splashpos" specifies the
1560 position as "x,y". If a positive number is given it is used as
1561 number of pixel from left/top. If a negative number is given it
1562 is used as number of pixel from right/bottom. You can also
1563 specify 'm' for centering the image.
1566 setenv splashpos m,m
1567 => image at center of screen
1569 setenv splashpos 30,20
1570 => image at x = 30 and y = 20
1572 setenv splashpos -10,m
1573 => vertically centered image
1574 at x = dspWidth - bmpWidth - 9
1576 CONFIG_SPLASH_SCREEN_PREPARE
1578 If this option is set then the board_splash_screen_prepare()
1579 function, which must be defined in your code, is called as part
1580 of the splash screen display sequence. It gives the board an
1581 opportunity to prepare the splash image data before it is
1582 processed and sent to the frame buffer by U-Boot.
1584 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1586 If this option is set, additionally to standard BMP
1587 images, gzipped BMP images can be displayed via the
1588 splashscreen support or the bmp command.
1590 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1592 If this option is set, 8-bit RLE compressed BMP images
1593 can be displayed via the splashscreen support or the
1596 - Do compresssing for memory range:
1599 If this option is set, it would use zlib deflate method
1600 to compress the specified memory at its best effort.
1602 - Compression support:
1605 If this option is set, support for bzip2 compressed
1606 images is included. If not, only uncompressed and gzip
1607 compressed images are supported.
1609 NOTE: the bzip2 algorithm requires a lot of RAM, so
1610 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1615 If this option is set, support for lzma compressed
1618 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1619 requires an amount of dynamic memory that is given by the
1622 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1624 Where lc and lp stand for, respectively, Literal context bits
1625 and Literal pos bits.
1627 This value is upper-bounded by 14MB in the worst case. Anyway,
1628 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1629 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1630 a very small buffer.
1632 Use the lzmainfo tool to determinate the lc and lp values and
1633 then calculate the amount of needed dynamic memory (ensuring
1634 the appropriate CONFIG_SYS_MALLOC_LEN value).
1639 The address of PHY on MII bus.
1641 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1643 The clock frequency of the MII bus
1647 If this option is set, support for speed/duplex
1648 detection of gigabit PHY is included.
1650 CONFIG_PHY_RESET_DELAY
1652 Some PHY like Intel LXT971A need extra delay after
1653 reset before any MII register access is possible.
1654 For such PHY, set this option to the usec delay
1655 required. (minimum 300usec for LXT971A)
1657 CONFIG_PHY_CMD_DELAY (ppc4xx)
1659 Some PHY like Intel LXT971A need extra delay after
1660 command issued before MII status register can be read
1670 Define a default value for Ethernet address to use
1671 for the respective Ethernet interface, in case this
1672 is not determined automatically.
1677 Define a default value for the IP address to use for
1678 the default Ethernet interface, in case this is not
1679 determined through e.g. bootp.
1680 (Environment variable "ipaddr")
1682 - Server IP address:
1685 Defines a default value for the IP address of a TFTP
1686 server to contact when using the "tftboot" command.
1687 (Environment variable "serverip")
1689 CONFIG_KEEP_SERVERADDR
1691 Keeps the server's MAC address, in the env 'serveraddr'
1692 for passing to bootargs (like Linux's netconsole option)
1694 - Gateway IP address:
1697 Defines a default value for the IP address of the
1698 default router where packets to other networks are
1700 (Environment variable "gatewayip")
1705 Defines a default value for the subnet mask (or
1706 routing prefix) which is used to determine if an IP
1707 address belongs to the local subnet or needs to be
1708 forwarded through a router.
1709 (Environment variable "netmask")
1711 - Multicast TFTP Mode:
1714 Defines whether you want to support multicast TFTP as per
1715 rfc-2090; for example to work with atftp. Lets lots of targets
1716 tftp down the same boot image concurrently. Note: the Ethernet
1717 driver in use must provide a function: mcast() to join/leave a
1720 - BOOTP Recovery Mode:
1721 CONFIG_BOOTP_RANDOM_DELAY
1723 If you have many targets in a network that try to
1724 boot using BOOTP, you may want to avoid that all
1725 systems send out BOOTP requests at precisely the same
1726 moment (which would happen for instance at recovery
1727 from a power failure, when all systems will try to
1728 boot, thus flooding the BOOTP server. Defining
1729 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1730 inserted before sending out BOOTP requests. The
1731 following delays are inserted then:
1733 1st BOOTP request: delay 0 ... 1 sec
1734 2nd BOOTP request: delay 0 ... 2 sec
1735 3rd BOOTP request: delay 0 ... 4 sec
1737 BOOTP requests: delay 0 ... 8 sec
1739 - DHCP Advanced Options:
1740 You can fine tune the DHCP functionality by defining
1741 CONFIG_BOOTP_* symbols:
1743 CONFIG_BOOTP_SUBNETMASK
1744 CONFIG_BOOTP_GATEWAY
1745 CONFIG_BOOTP_HOSTNAME
1746 CONFIG_BOOTP_NISDOMAIN
1747 CONFIG_BOOTP_BOOTPATH
1748 CONFIG_BOOTP_BOOTFILESIZE
1751 CONFIG_BOOTP_SEND_HOSTNAME
1752 CONFIG_BOOTP_NTPSERVER
1753 CONFIG_BOOTP_TIMEOFFSET
1754 CONFIG_BOOTP_VENDOREX
1755 CONFIG_BOOTP_MAY_FAIL
1757 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1758 environment variable, not the BOOTP server.
1760 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1761 after the configured retry count, the call will fail
1762 instead of starting over. This can be used to fail over
1763 to Link-local IP address configuration if the DHCP server
1766 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1767 serverip from a DHCP server, it is possible that more
1768 than one DNS serverip is offered to the client.
1769 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1770 serverip will be stored in the additional environment
1771 variable "dnsip2". The first DNS serverip is always
1772 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1775 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1776 to do a dynamic update of a DNS server. To do this, they
1777 need the hostname of the DHCP requester.
1778 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1779 of the "hostname" environment variable is passed as
1780 option 12 to the DHCP server.
1782 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1784 A 32bit value in microseconds for a delay between
1785 receiving a "DHCP Offer" and sending the "DHCP Request".
1786 This fixes a problem with certain DHCP servers that don't
1787 respond 100% of the time to a "DHCP request". E.g. On an
1788 AT91RM9200 processor running at 180MHz, this delay needed
1789 to be *at least* 15,000 usec before a Windows Server 2003
1790 DHCP server would reply 100% of the time. I recommend at
1791 least 50,000 usec to be safe. The alternative is to hope
1792 that one of the retries will be successful but note that
1793 the DHCP timeout and retry process takes a longer than
1796 - Link-local IP address negotiation:
1797 Negotiate with other link-local clients on the local network
1798 for an address that doesn't require explicit configuration.
1799 This is especially useful if a DHCP server cannot be guaranteed
1800 to exist in all environments that the device must operate.
1802 See doc/README.link-local for more information.
1805 CONFIG_CDP_DEVICE_ID
1807 The device id used in CDP trigger frames.
1809 CONFIG_CDP_DEVICE_ID_PREFIX
1811 A two character string which is prefixed to the MAC address
1816 A printf format string which contains the ascii name of
1817 the port. Normally is set to "eth%d" which sets
1818 eth0 for the first Ethernet, eth1 for the second etc.
1820 CONFIG_CDP_CAPABILITIES
1822 A 32bit integer which indicates the device capabilities;
1823 0x00000010 for a normal host which does not forwards.
1827 An ascii string containing the version of the software.
1831 An ascii string containing the name of the platform.
1835 A 32bit integer sent on the trigger.
1837 CONFIG_CDP_POWER_CONSUMPTION
1839 A 16bit integer containing the power consumption of the
1840 device in .1 of milliwatts.
1842 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1844 A byte containing the id of the VLAN.
1846 - Status LED: CONFIG_STATUS_LED
1848 Several configurations allow to display the current
1849 status using a LED. For instance, the LED will blink
1850 fast while running U-Boot code, stop blinking as
1851 soon as a reply to a BOOTP request was received, and
1852 start blinking slow once the Linux kernel is running
1853 (supported by a status LED driver in the Linux
1854 kernel). Defining CONFIG_STATUS_LED enables this
1857 - CAN Support: CONFIG_CAN_DRIVER
1859 Defining CONFIG_CAN_DRIVER enables CAN driver support
1860 on those systems that support this (optional)
1861 feature, like the TQM8xxL modules.
1863 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1865 These enable I2C serial bus commands. Defining either of
1866 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1867 include the appropriate I2C driver for the selected CPU.
1869 This will allow you to use i2c commands at the u-boot
1870 command line (as long as you set CONFIG_CMD_I2C in
1871 CONFIG_COMMANDS) and communicate with i2c based realtime
1872 clock chips. See common/cmd_i2c.c for a description of the
1873 command line interface.
1875 CONFIG_HARD_I2C selects a hardware I2C controller.
1877 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1878 bit-banging) driver instead of CPM or similar hardware
1881 There are several other quantities that must also be
1882 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1884 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1885 to be the frequency (in Hz) at which you wish your i2c bus
1886 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1887 the CPU's i2c node address).
1889 Now, the u-boot i2c code for the mpc8xx
1890 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1891 and so its address should therefore be cleared to 0 (See,
1892 eg, MPC823e User's Manual p.16-473). So, set
1893 CONFIG_SYS_I2C_SLAVE to 0.
1895 CONFIG_SYS_I2C_INIT_MPC5XXX
1897 When a board is reset during an i2c bus transfer
1898 chips might think that the current transfer is still
1899 in progress. Reset the slave devices by sending start
1900 commands until the slave device responds.
1902 That's all that's required for CONFIG_HARD_I2C.
1904 If you use the software i2c interface (CONFIG_SOFT_I2C)
1905 then the following macros need to be defined (examples are
1906 from include/configs/lwmon.h):
1910 (Optional). Any commands necessary to enable the I2C
1911 controller or configure ports.
1913 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1917 (Only for MPC8260 CPU). The I/O port to use (the code
1918 assumes both bits are on the same port). Valid values
1919 are 0..3 for ports A..D.
1923 The code necessary to make the I2C data line active
1924 (driven). If the data line is open collector, this
1927 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1931 The code necessary to make the I2C data line tri-stated
1932 (inactive). If the data line is open collector, this
1935 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1939 Code that returns TRUE if the I2C data line is high,
1942 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1946 If <bit> is TRUE, sets the I2C data line high. If it
1947 is FALSE, it clears it (low).
1949 eg: #define I2C_SDA(bit) \
1950 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1951 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1955 If <bit> is TRUE, sets the I2C clock line high. If it
1956 is FALSE, it clears it (low).
1958 eg: #define I2C_SCL(bit) \
1959 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1960 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1964 This delay is invoked four times per clock cycle so this
1965 controls the rate of data transfer. The data rate thus
1966 is 1 / (I2C_DELAY * 4). Often defined to be something
1969 #define I2C_DELAY udelay(2)
1971 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1973 If your arch supports the generic GPIO framework (asm/gpio.h),
1974 then you may alternatively define the two GPIOs that are to be
1975 used as SCL / SDA. Any of the previous I2C_xxx macros will
1976 have GPIO-based defaults assigned to them as appropriate.
1978 You should define these to the GPIO value as given directly to
1979 the generic GPIO functions.
1981 CONFIG_SYS_I2C_INIT_BOARD
1983 When a board is reset during an i2c bus transfer
1984 chips might think that the current transfer is still
1985 in progress. On some boards it is possible to access
1986 the i2c SCLK line directly, either by using the
1987 processor pin as a GPIO or by having a second pin
1988 connected to the bus. If this option is defined a
1989 custom i2c_init_board() routine in boards/xxx/board.c
1990 is run early in the boot sequence.
1992 CONFIG_SYS_I2C_BOARD_LATE_INIT
1994 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1995 defined a custom i2c_board_late_init() routine in
1996 boards/xxx/board.c is run AFTER the operations in i2c_init()
1997 is completed. This callpoint can be used to unreset i2c bus
1998 using CPU i2c controller register accesses for CPUs whose i2c
1999 controller provide such a method. It is called at the end of
2000 i2c_init() to allow i2c_init operations to setup the i2c bus
2001 controller on the CPU (e.g. setting bus speed & slave address).
2003 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2005 This option enables configuration of bi_iic_fast[] flags
2006 in u-boot bd_info structure based on u-boot environment
2007 variable "i2cfast". (see also i2cfast)
2009 CONFIG_I2C_MULTI_BUS
2011 This option allows the use of multiple I2C buses, each of which
2012 must have a controller. At any point in time, only one bus is
2013 active. To switch to a different bus, use the 'i2c dev' command.
2014 Note that bus numbering is zero-based.
2016 CONFIG_SYS_I2C_NOPROBES
2018 This option specifies a list of I2C devices that will be skipped
2019 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2020 is set, specify a list of bus-device pairs. Otherwise, specify
2021 a 1D array of device addresses
2024 #undef CONFIG_I2C_MULTI_BUS
2025 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2027 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2029 #define CONFIG_I2C_MULTI_BUS
2030 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2032 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2034 CONFIG_SYS_SPD_BUS_NUM
2036 If defined, then this indicates the I2C bus number for DDR SPD.
2037 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2039 CONFIG_SYS_RTC_BUS_NUM
2041 If defined, then this indicates the I2C bus number for the RTC.
2042 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2044 CONFIG_SYS_DTT_BUS_NUM
2046 If defined, then this indicates the I2C bus number for the DTT.
2047 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2049 CONFIG_SYS_I2C_DTT_ADDR:
2051 If defined, specifies the I2C address of the DTT device.
2052 If not defined, then U-Boot uses predefined value for
2053 specified DTT device.
2057 Define this option if you want to use Freescale's I2C driver in
2058 drivers/i2c/fsl_i2c.c.
2062 Define this option if you have I2C devices reached over 1 .. n
2063 I2C Muxes like the pca9544a. This option addes a new I2C
2064 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2065 new I2C Bus to the existing I2C Busses. If you select the
2066 new Bus with "i2c dev", u-bbot sends first the commandos for
2067 the muxes to activate this new "bus".
2069 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2073 Adding a new I2C Bus reached over 2 pca9544a muxes
2074 The First mux with address 70 and channel 6
2075 The Second mux with address 71 and channel 4
2077 => i2c bus pca9544a:70:6:pca9544a:71:4
2079 Use the "i2c bus" command without parameter, to get a list
2080 of I2C Busses with muxes:
2083 Busses reached over muxes:
2085 reached over Mux(es):
2088 reached over Mux(es):
2093 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2094 u-boot first sends the command to the mux@70 to enable
2095 channel 6, and then the command to the mux@71 to enable
2098 After that, you can use the "normal" i2c commands as
2099 usual to communicate with your I2C devices behind
2102 This option is actually implemented for the bitbanging
2103 algorithm in common/soft_i2c.c and for the Hardware I2C
2104 Bus on the MPC8260. But it should be not so difficult
2105 to add this option to other architectures.
2107 CONFIG_SOFT_I2C_READ_REPEATED_START
2109 defining this will force the i2c_read() function in
2110 the soft_i2c driver to perform an I2C repeated start
2111 between writing the address pointer and reading the
2112 data. If this define is omitted the default behaviour
2113 of doing a stop-start sequence will be used. Most I2C
2114 devices can use either method, but some require one or
2117 - SPI Support: CONFIG_SPI
2119 Enables SPI driver (so far only tested with
2120 SPI EEPROM, also an instance works with Crystal A/D and
2121 D/As on the SACSng board)
2125 Enables the driver for SPI controller on SuperH. Currently
2126 only SH7757 is supported.
2130 Enables extended (16-bit) SPI EEPROM addressing.
2131 (symmetrical to CONFIG_I2C_X)
2135 Enables a software (bit-bang) SPI driver rather than
2136 using hardware support. This is a general purpose
2137 driver that only requires three general I/O port pins
2138 (two outputs, one input) to function. If this is
2139 defined, the board configuration must define several
2140 SPI configuration items (port pins to use, etc). For
2141 an example, see include/configs/sacsng.h.
2145 Enables a hardware SPI driver for general-purpose reads
2146 and writes. As with CONFIG_SOFT_SPI, the board configuration
2147 must define a list of chip-select function pointers.
2148 Currently supported on some MPC8xxx processors. For an
2149 example, see include/configs/mpc8349emds.h.
2153 Enables the driver for the SPI controllers on i.MX and MXC
2154 SoCs. Currently i.MX31/35/51 are supported.
2156 - FPGA Support: CONFIG_FPGA
2158 Enables FPGA subsystem.
2160 CONFIG_FPGA_<vendor>
2162 Enables support for specific chip vendors.
2165 CONFIG_FPGA_<family>
2167 Enables support for FPGA family.
2168 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2172 Specify the number of FPGA devices to support.
2174 CONFIG_SYS_FPGA_PROG_FEEDBACK
2176 Enable printing of hash marks during FPGA configuration.
2178 CONFIG_SYS_FPGA_CHECK_BUSY
2180 Enable checks on FPGA configuration interface busy
2181 status by the configuration function. This option
2182 will require a board or device specific function to
2187 If defined, a function that provides delays in the FPGA
2188 configuration driver.
2190 CONFIG_SYS_FPGA_CHECK_CTRLC
2191 Allow Control-C to interrupt FPGA configuration
2193 CONFIG_SYS_FPGA_CHECK_ERROR
2195 Check for configuration errors during FPGA bitfile
2196 loading. For example, abort during Virtex II
2197 configuration if the INIT_B line goes low (which
2198 indicated a CRC error).
2200 CONFIG_SYS_FPGA_WAIT_INIT
2202 Maximum time to wait for the INIT_B line to deassert
2203 after PROB_B has been deasserted during a Virtex II
2204 FPGA configuration sequence. The default time is 500
2207 CONFIG_SYS_FPGA_WAIT_BUSY
2209 Maximum time to wait for BUSY to deassert during
2210 Virtex II FPGA configuration. The default is 5 ms.
2212 CONFIG_SYS_FPGA_WAIT_CONFIG
2214 Time to wait after FPGA configuration. The default is
2217 - Configuration Management:
2220 If defined, this string will be added to the U-Boot
2221 version information (U_BOOT_VERSION)
2223 - Vendor Parameter Protection:
2225 U-Boot considers the values of the environment
2226 variables "serial#" (Board Serial Number) and
2227 "ethaddr" (Ethernet Address) to be parameters that
2228 are set once by the board vendor / manufacturer, and
2229 protects these variables from casual modification by
2230 the user. Once set, these variables are read-only,
2231 and write or delete attempts are rejected. You can
2232 change this behaviour:
2234 If CONFIG_ENV_OVERWRITE is #defined in your config
2235 file, the write protection for vendor parameters is
2236 completely disabled. Anybody can change or delete
2239 Alternatively, if you #define _both_ CONFIG_ETHADDR
2240 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2241 Ethernet address is installed in the environment,
2242 which can be changed exactly ONCE by the user. [The
2243 serial# is unaffected by this, i. e. it remains
2246 The same can be accomplished in a more flexible way
2247 for any variable by configuring the type of access
2248 to allow for those variables in the ".flags" variable
2249 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2254 Define this variable to enable the reservation of
2255 "protected RAM", i. e. RAM which is not overwritten
2256 by U-Boot. Define CONFIG_PRAM to hold the number of
2257 kB you want to reserve for pRAM. You can overwrite
2258 this default value by defining an environment
2259 variable "pram" to the number of kB you want to
2260 reserve. Note that the board info structure will
2261 still show the full amount of RAM. If pRAM is
2262 reserved, a new environment variable "mem" will
2263 automatically be defined to hold the amount of
2264 remaining RAM in a form that can be passed as boot
2265 argument to Linux, for instance like that:
2267 setenv bootargs ... mem=\${mem}
2270 This way you can tell Linux not to use this memory,
2271 either, which results in a memory region that will
2272 not be affected by reboots.
2274 *WARNING* If your board configuration uses automatic
2275 detection of the RAM size, you must make sure that
2276 this memory test is non-destructive. So far, the
2277 following board configurations are known to be
2280 IVMS8, IVML24, SPD8xx, TQM8xxL,
2281 HERMES, IP860, RPXlite, LWMON,
2284 - Access to physical memory region (> 4GB)
2285 Some basic support is provided for operations on memory not
2286 normally accessible to U-Boot - e.g. some architectures
2287 support access to more than 4GB of memory on 32-bit
2288 machines using physical address extension or similar.
2289 Define CONFIG_PHYSMEM to access this basic support, which
2290 currently only supports clearing the memory.
2295 Define this variable to stop the system in case of a
2296 fatal error, so that you have to reset it manually.
2297 This is probably NOT a good idea for an embedded
2298 system where you want the system to reboot
2299 automatically as fast as possible, but it may be
2300 useful during development since you can try to debug
2301 the conditions that lead to the situation.
2303 CONFIG_NET_RETRY_COUNT
2305 This variable defines the number of retries for
2306 network operations like ARP, RARP, TFTP, or BOOTP
2307 before giving up the operation. If not defined, a
2308 default value of 5 is used.
2312 Timeout waiting for an ARP reply in milliseconds.
2316 Timeout in milliseconds used in NFS protocol.
2317 If you encounter "ERROR: Cannot umount" in nfs command,
2318 try longer timeout such as
2319 #define CONFIG_NFS_TIMEOUT 10000UL
2321 - Command Interpreter:
2322 CONFIG_AUTO_COMPLETE
2324 Enable auto completion of commands using TAB.
2326 Note that this feature has NOT been implemented yet
2327 for the "hush" shell.
2330 CONFIG_SYS_HUSH_PARSER
2332 Define this variable to enable the "hush" shell (from
2333 Busybox) as command line interpreter, thus enabling
2334 powerful command line syntax like
2335 if...then...else...fi conditionals or `&&' and '||'
2336 constructs ("shell scripts").
2338 If undefined, you get the old, much simpler behaviour
2339 with a somewhat smaller memory footprint.
2342 CONFIG_SYS_PROMPT_HUSH_PS2
2344 This defines the secondary prompt string, which is
2345 printed when the command interpreter needs more input
2346 to complete a command. Usually "> ".
2350 In the current implementation, the local variables
2351 space and global environment variables space are
2352 separated. Local variables are those you define by
2353 simply typing `name=value'. To access a local
2354 variable later on, you have write `$name' or
2355 `${name}'; to execute the contents of a variable
2356 directly type `$name' at the command prompt.
2358 Global environment variables are those you use
2359 setenv/printenv to work with. To run a command stored
2360 in such a variable, you need to use the run command,
2361 and you must not use the '$' sign to access them.
2363 To store commands and special characters in a
2364 variable, please use double quotation marks
2365 surrounding the whole text of the variable, instead
2366 of the backslashes before semicolons and special
2369 - Commandline Editing and History:
2370 CONFIG_CMDLINE_EDITING
2372 Enable editing and History functions for interactive
2373 commandline input operations
2375 - Default Environment:
2376 CONFIG_EXTRA_ENV_SETTINGS
2378 Define this to contain any number of null terminated
2379 strings (variable = value pairs) that will be part of
2380 the default environment compiled into the boot image.
2382 For example, place something like this in your
2383 board's config file:
2385 #define CONFIG_EXTRA_ENV_SETTINGS \
2389 Warning: This method is based on knowledge about the
2390 internal format how the environment is stored by the
2391 U-Boot code. This is NOT an official, exported
2392 interface! Although it is unlikely that this format
2393 will change soon, there is no guarantee either.
2394 You better know what you are doing here.
2396 Note: overly (ab)use of the default environment is
2397 discouraged. Make sure to check other ways to preset
2398 the environment like the "source" command or the
2401 CONFIG_ENV_VARS_UBOOT_CONFIG
2403 Define this in order to add variables describing the
2404 U-Boot build configuration to the default environment.
2405 These will be named arch, cpu, board, vendor, and soc.
2407 Enabling this option will cause the following to be defined:
2415 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2417 Define this in order to add variables describing certain
2418 run-time determined information about the hardware to the
2419 environment. These will be named board_name, board_rev.
2421 CONFIG_DELAY_ENVIRONMENT
2423 Normally the environment is loaded when the board is
2424 intialised so that it is available to U-Boot. This inhibits
2425 that so that the environment is not available until
2426 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2427 this is instead controlled by the value of
2428 /config/load-environment.
2430 - DataFlash Support:
2431 CONFIG_HAS_DATAFLASH
2433 Defining this option enables DataFlash features and
2434 allows to read/write in Dataflash via the standard
2437 - Serial Flash support
2440 Defining this option enables SPI flash commands
2441 'sf probe/read/write/erase/update'.
2443 Usage requires an initial 'probe' to define the serial
2444 flash parameters, followed by read/write/erase/update
2447 The following defaults may be provided by the platform
2448 to handle the common case when only a single serial
2449 flash is present on the system.
2451 CONFIG_SF_DEFAULT_BUS Bus identifier
2452 CONFIG_SF_DEFAULT_CS Chip-select
2453 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2454 CONFIG_SF_DEFAULT_SPEED in Hz
2458 Define this option to include a destructive SPI flash
2461 - SystemACE Support:
2464 Adding this option adds support for Xilinx SystemACE
2465 chips attached via some sort of local bus. The address
2466 of the chip must also be defined in the
2467 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2469 #define CONFIG_SYSTEMACE
2470 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2472 When SystemACE support is added, the "ace" device type
2473 becomes available to the fat commands, i.e. fatls.
2475 - TFTP Fixed UDP Port:
2478 If this is defined, the environment variable tftpsrcp
2479 is used to supply the TFTP UDP source port value.
2480 If tftpsrcp isn't defined, the normal pseudo-random port
2481 number generator is used.
2483 Also, the environment variable tftpdstp is used to supply
2484 the TFTP UDP destination port value. If tftpdstp isn't
2485 defined, the normal port 69 is used.
2487 The purpose for tftpsrcp is to allow a TFTP server to
2488 blindly start the TFTP transfer using the pre-configured
2489 target IP address and UDP port. This has the effect of
2490 "punching through" the (Windows XP) firewall, allowing
2491 the remainder of the TFTP transfer to proceed normally.
2492 A better solution is to properly configure the firewall,
2493 but sometimes that is not allowed.
2498 This enables a generic 'hash' command which can produce
2499 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2503 Enable the hash verify command (hash -v). This adds to code
2506 CONFIG_SHA1 - support SHA1 hashing
2507 CONFIG_SHA256 - support SHA256 hashing
2509 Note: There is also a sha1sum command, which should perhaps
2510 be deprecated in favour of 'hash sha1'.
2512 - Show boot progress:
2513 CONFIG_SHOW_BOOT_PROGRESS
2515 Defining this option allows to add some board-
2516 specific code (calling a user-provided function
2517 "show_boot_progress(int)") that enables you to show
2518 the system's boot progress on some display (for
2519 example, some LED's) on your board. At the moment,
2520 the following checkpoints are implemented:
2522 - Detailed boot stage timing
2524 Define this option to get detailed timing of each stage
2525 of the boot process.
2527 CONFIG_BOOTSTAGE_USER_COUNT
2528 This is the number of available user bootstage records.
2529 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2530 a new ID will be allocated from this stash. If you exceed
2531 the limit, recording will stop.
2533 CONFIG_BOOTSTAGE_REPORT
2534 Define this to print a report before boot, similar to this:
2536 Timer summary in microseconds:
2539 3,575,678 3,575,678 board_init_f start
2540 3,575,695 17 arch_cpu_init A9
2541 3,575,777 82 arch_cpu_init done
2542 3,659,598 83,821 board_init_r start
2543 3,910,375 250,777 main_loop
2544 29,916,167 26,005,792 bootm_start
2545 30,361,327 445,160 start_kernel
2547 CONFIG_CMD_BOOTSTAGE
2548 Add a 'bootstage' command which supports printing a report
2549 and un/stashing of bootstage data.
2551 CONFIG_BOOTSTAGE_FDT
2552 Stash the bootstage information in the FDT. A root 'bootstage'
2553 node is created with each bootstage id as a child. Each child
2554 has a 'name' property and either 'mark' containing the
2555 mark time in microsecond, or 'accum' containing the
2556 accumulated time for that bootstage id in microseconds.
2561 name = "board_init_f";
2570 Code in the Linux kernel can find this in /proc/devicetree.
2572 Legacy uImage format:
2575 1 common/cmd_bootm.c before attempting to boot an image
2576 -1 common/cmd_bootm.c Image header has bad magic number
2577 2 common/cmd_bootm.c Image header has correct magic number
2578 -2 common/cmd_bootm.c Image header has bad checksum
2579 3 common/cmd_bootm.c Image header has correct checksum
2580 -3 common/cmd_bootm.c Image data has bad checksum
2581 4 common/cmd_bootm.c Image data has correct checksum
2582 -4 common/cmd_bootm.c Image is for unsupported architecture
2583 5 common/cmd_bootm.c Architecture check OK
2584 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2585 6 common/cmd_bootm.c Image Type check OK
2586 -6 common/cmd_bootm.c gunzip uncompression error
2587 -7 common/cmd_bootm.c Unimplemented compression type
2588 7 common/cmd_bootm.c Uncompression OK
2589 8 common/cmd_bootm.c No uncompress/copy overwrite error
2590 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2592 9 common/image.c Start initial ramdisk verification
2593 -10 common/image.c Ramdisk header has bad magic number
2594 -11 common/image.c Ramdisk header has bad checksum
2595 10 common/image.c Ramdisk header is OK
2596 -12 common/image.c Ramdisk data has bad checksum
2597 11 common/image.c Ramdisk data has correct checksum
2598 12 common/image.c Ramdisk verification complete, start loading
2599 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2600 13 common/image.c Start multifile image verification
2601 14 common/image.c No initial ramdisk, no multifile, continue.
2603 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2605 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2606 -31 post/post.c POST test failed, detected by post_output_backlog()
2607 -32 post/post.c POST test failed, detected by post_run_single()
2609 34 common/cmd_doc.c before loading a Image from a DOC device
2610 -35 common/cmd_doc.c Bad usage of "doc" command
2611 35 common/cmd_doc.c correct usage of "doc" command
2612 -36 common/cmd_doc.c No boot device
2613 36 common/cmd_doc.c correct boot device
2614 -37 common/cmd_doc.c Unknown Chip ID on boot device
2615 37 common/cmd_doc.c correct chip ID found, device available
2616 -38 common/cmd_doc.c Read Error on boot device
2617 38 common/cmd_doc.c reading Image header from DOC device OK
2618 -39 common/cmd_doc.c Image header has bad magic number
2619 39 common/cmd_doc.c Image header has correct magic number
2620 -40 common/cmd_doc.c Error reading Image from DOC device
2621 40 common/cmd_doc.c Image header has correct magic number
2622 41 common/cmd_ide.c before loading a Image from a IDE device
2623 -42 common/cmd_ide.c Bad usage of "ide" command
2624 42 common/cmd_ide.c correct usage of "ide" command
2625 -43 common/cmd_ide.c No boot device
2626 43 common/cmd_ide.c boot device found
2627 -44 common/cmd_ide.c Device not available
2628 44 common/cmd_ide.c Device available
2629 -45 common/cmd_ide.c wrong partition selected
2630 45 common/cmd_ide.c partition selected
2631 -46 common/cmd_ide.c Unknown partition table
2632 46 common/cmd_ide.c valid partition table found
2633 -47 common/cmd_ide.c Invalid partition type
2634 47 common/cmd_ide.c correct partition type
2635 -48 common/cmd_ide.c Error reading Image Header on boot device
2636 48 common/cmd_ide.c reading Image Header from IDE device OK
2637 -49 common/cmd_ide.c Image header has bad magic number
2638 49 common/cmd_ide.c Image header has correct magic number
2639 -50 common/cmd_ide.c Image header has bad checksum
2640 50 common/cmd_ide.c Image header has correct checksum
2641 -51 common/cmd_ide.c Error reading Image from IDE device
2642 51 common/cmd_ide.c reading Image from IDE device OK
2643 52 common/cmd_nand.c before loading a Image from a NAND device
2644 -53 common/cmd_nand.c Bad usage of "nand" command
2645 53 common/cmd_nand.c correct usage of "nand" command
2646 -54 common/cmd_nand.c No boot device
2647 54 common/cmd_nand.c boot device found
2648 -55 common/cmd_nand.c Unknown Chip ID on boot device
2649 55 common/cmd_nand.c correct chip ID found, device available
2650 -56 common/cmd_nand.c Error reading Image Header on boot device
2651 56 common/cmd_nand.c reading Image Header from NAND device OK
2652 -57 common/cmd_nand.c Image header has bad magic number
2653 57 common/cmd_nand.c Image header has correct magic number
2654 -58 common/cmd_nand.c Error reading Image from NAND device
2655 58 common/cmd_nand.c reading Image from NAND device OK
2657 -60 common/env_common.c Environment has a bad CRC, using default
2659 64 net/eth.c starting with Ethernet configuration.
2660 -64 net/eth.c no Ethernet found.
2661 65 net/eth.c Ethernet found.
2663 -80 common/cmd_net.c usage wrong
2664 80 common/cmd_net.c before calling NetLoop()
2665 -81 common/cmd_net.c some error in NetLoop() occurred
2666 81 common/cmd_net.c NetLoop() back without error
2667 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2668 82 common/cmd_net.c trying automatic boot
2669 83 common/cmd_net.c running "source" command
2670 -83 common/cmd_net.c some error in automatic boot or "source" command
2671 84 common/cmd_net.c end without errors
2676 100 common/cmd_bootm.c Kernel FIT Image has correct format
2677 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2678 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2679 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2680 102 common/cmd_bootm.c Kernel unit name specified
2681 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2682 103 common/cmd_bootm.c Found configuration node
2683 104 common/cmd_bootm.c Got kernel subimage node offset
2684 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2685 105 common/cmd_bootm.c Kernel subimage hash verification OK
2686 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2687 106 common/cmd_bootm.c Architecture check OK
2688 -106 common/cmd_bootm.c Kernel subimage has wrong type
2689 107 common/cmd_bootm.c Kernel subimage type OK
2690 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2691 108 common/cmd_bootm.c Got kernel subimage data/size
2692 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2693 -109 common/cmd_bootm.c Can't get kernel subimage type
2694 -110 common/cmd_bootm.c Can't get kernel subimage comp
2695 -111 common/cmd_bootm.c Can't get kernel subimage os
2696 -112 common/cmd_bootm.c Can't get kernel subimage load address
2697 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2699 120 common/image.c Start initial ramdisk verification
2700 -120 common/image.c Ramdisk FIT image has incorrect format
2701 121 common/image.c Ramdisk FIT image has correct format
2702 122 common/image.c No ramdisk subimage unit name, using configuration
2703 -122 common/image.c Can't get configuration for ramdisk subimage
2704 123 common/image.c Ramdisk unit name specified
2705 -124 common/image.c Can't get ramdisk subimage node offset
2706 125 common/image.c Got ramdisk subimage node offset
2707 -125 common/image.c Ramdisk subimage hash verification failed
2708 126 common/image.c Ramdisk subimage hash verification OK
2709 -126 common/image.c Ramdisk subimage for unsupported architecture
2710 127 common/image.c Architecture check OK
2711 -127 common/image.c Can't get ramdisk subimage data/size
2712 128 common/image.c Got ramdisk subimage data/size
2713 129 common/image.c Can't get ramdisk load address
2714 -129 common/image.c Got ramdisk load address
2716 -130 common/cmd_doc.c Incorrect FIT image format
2717 131 common/cmd_doc.c FIT image format OK
2719 -140 common/cmd_ide.c Incorrect FIT image format
2720 141 common/cmd_ide.c FIT image format OK
2722 -150 common/cmd_nand.c Incorrect FIT image format
2723 151 common/cmd_nand.c FIT image format OK
2725 - FIT image support:
2727 Enable support for the FIT uImage format.
2729 CONFIG_FIT_BEST_MATCH
2730 When no configuration is explicitly selected, default to the
2731 one whose fdt's compatibility field best matches that of
2732 U-Boot itself. A match is considered "best" if it matches the
2733 most specific compatibility entry of U-Boot's fdt's root node.
2734 The order of entries in the configuration's fdt is ignored.
2736 - Standalone program support:
2737 CONFIG_STANDALONE_LOAD_ADDR
2739 This option defines a board specific value for the
2740 address where standalone program gets loaded, thus
2741 overwriting the architecture dependent default
2744 - Frame Buffer Address:
2747 Define CONFIG_FB_ADDR if you want to use specific
2748 address for frame buffer. This is typically the case
2749 when using a graphics controller has separate video
2750 memory. U-Boot will then place the frame buffer at
2751 the given address instead of dynamically reserving it
2752 in system RAM by calling lcd_setmem(), which grabs
2753 the memory for the frame buffer depending on the
2754 configured panel size.
2756 Please see board_init_f function.
2758 - Automatic software updates via TFTP server
2760 CONFIG_UPDATE_TFTP_CNT_MAX
2761 CONFIG_UPDATE_TFTP_MSEC_MAX
2763 These options enable and control the auto-update feature;
2764 for a more detailed description refer to doc/README.update.
2766 - MTD Support (mtdparts command, UBI support)
2769 Adds the MTD device infrastructure from the Linux kernel.
2770 Needed for mtdparts command support.
2772 CONFIG_MTD_PARTITIONS
2774 Adds the MTD partitioning infrastructure from the Linux
2775 kernel. Needed for UBI support.
2779 Enable building of SPL globally.
2782 LDSCRIPT for linking the SPL binary.
2785 Maximum binary size (text, data and rodata) of the SPL binary.
2787 CONFIG_SPL_TEXT_BASE
2788 TEXT_BASE for linking the SPL binary.
2790 CONFIG_SPL_RELOC_TEXT_BASE
2791 Address to relocate to. If unspecified, this is equal to
2792 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2794 CONFIG_SPL_BSS_START_ADDR
2795 Link address for the BSS within the SPL binary.
2797 CONFIG_SPL_BSS_MAX_SIZE
2798 Maximum binary size of the BSS section of the SPL binary.
2801 Adress of the start of the stack SPL will use
2803 CONFIG_SPL_RELOC_STACK
2804 Adress of the start of the stack SPL will use after
2805 relocation. If unspecified, this is equal to
2808 CONFIG_SYS_SPL_MALLOC_START
2809 Starting address of the malloc pool used in SPL.
2811 CONFIG_SYS_SPL_MALLOC_SIZE
2812 The size of the malloc pool used in SPL.
2814 CONFIG_SPL_FRAMEWORK
2815 Enable the SPL framework under common/. This framework
2816 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2817 NAND loading of the Linux Kernel.
2819 CONFIG_SPL_DISPLAY_PRINT
2820 For ARM, enable an optional function to print more information
2821 about the running system.
2823 CONFIG_SPL_INIT_MINIMAL
2824 Arch init code should be built for a very small image
2826 CONFIG_SPL_LIBCOMMON_SUPPORT
2827 Support for common/libcommon.o in SPL binary
2829 CONFIG_SPL_LIBDISK_SUPPORT
2830 Support for disk/libdisk.o in SPL binary
2832 CONFIG_SPL_I2C_SUPPORT
2833 Support for drivers/i2c/libi2c.o in SPL binary
2835 CONFIG_SPL_GPIO_SUPPORT
2836 Support for drivers/gpio/libgpio.o in SPL binary
2838 CONFIG_SPL_MMC_SUPPORT
2839 Support for drivers/mmc/libmmc.o in SPL binary
2841 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2842 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2843 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2844 Address, size and partition on the MMC to load U-Boot from
2845 when the MMC is being used in raw mode.
2847 CONFIG_SPL_FAT_SUPPORT
2848 Support for fs/fat/libfat.o in SPL binary
2850 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2851 Filename to read to load U-Boot when reading from FAT
2853 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2854 Set this for NAND SPL on PPC mpc83xx targets, so that
2855 start.S waits for the rest of the SPL to load before
2856 continuing (the hardware starts execution after just
2857 loading the first page rather than the full 4K).
2859 CONFIG_SPL_NAND_BASE
2860 Include nand_base.c in the SPL. Requires
2861 CONFIG_SPL_NAND_DRIVERS.
2863 CONFIG_SPL_NAND_DRIVERS
2864 SPL uses normal NAND drivers, not minimal drivers.
2867 Include standard software ECC in the SPL
2869 CONFIG_SPL_NAND_SIMPLE
2870 Support for NAND boot using simple NAND drivers that
2871 expose the cmd_ctrl() interface.
2873 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2874 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2875 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2876 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2877 CONFIG_SYS_NAND_ECCBYTES
2878 Defines the size and behavior of the NAND that SPL uses
2881 CONFIG_SYS_NAND_U_BOOT_OFFS
2882 Location in NAND to read U-Boot from
2884 CONFIG_SYS_NAND_U_BOOT_DST
2885 Location in memory to load U-Boot to
2887 CONFIG_SYS_NAND_U_BOOT_SIZE
2888 Size of image to load
2890 CONFIG_SYS_NAND_U_BOOT_START
2891 Entry point in loaded image to jump to
2893 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2894 Define this if you need to first read the OOB and then the
2895 data. This is used for example on davinci plattforms.
2897 CONFIG_SPL_OMAP3_ID_NAND
2898 Support for an OMAP3-specific set of functions to return the
2899 ID and MFR of the first attached NAND chip, if present.
2901 CONFIG_SPL_SERIAL_SUPPORT
2902 Support for drivers/serial/libserial.o in SPL binary
2904 CONFIG_SPL_SPI_FLASH_SUPPORT
2905 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2907 CONFIG_SPL_SPI_SUPPORT
2908 Support for drivers/spi/libspi.o in SPL binary
2910 CONFIG_SPL_RAM_DEVICE
2911 Support for running image already present in ram, in SPL binary
2913 CONFIG_SPL_LIBGENERIC_SUPPORT
2914 Support for lib/libgeneric.o in SPL binary
2917 Linker address to which the SPL should be padded before
2918 appending the SPL payload.
2921 Final target image containing SPL and payload. Some SPLs
2922 use an arch-specific makefile fragment instead, for
2923 example if more than one image needs to be produced.
2928 [so far only for SMDK2400 boards]
2930 - Modem support enable:
2931 CONFIG_MODEM_SUPPORT
2933 - RTS/CTS Flow control enable:
2936 - Modem debug support:
2937 CONFIG_MODEM_SUPPORT_DEBUG
2939 Enables debugging stuff (char screen[1024], dbg())
2940 for modem support. Useful only with BDI2000.
2942 - Interrupt support (PPC):
2944 There are common interrupt_init() and timer_interrupt()
2945 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2946 for CPU specific initialization. interrupt_init_cpu()
2947 should set decrementer_count to appropriate value. If
2948 CPU resets decrementer automatically after interrupt
2949 (ppc4xx) it should set decrementer_count to zero.
2950 timer_interrupt() calls timer_interrupt_cpu() for CPU
2951 specific handling. If board has watchdog / status_led
2952 / other_activity_monitor it works automatically from
2953 general timer_interrupt().
2957 In the target system modem support is enabled when a
2958 specific key (key combination) is pressed during
2959 power-on. Otherwise U-Boot will boot normally
2960 (autoboot). The key_pressed() function is called from
2961 board_init(). Currently key_pressed() is a dummy
2962 function, returning 1 and thus enabling modem
2965 If there are no modem init strings in the
2966 environment, U-Boot proceed to autoboot; the
2967 previous output (banner, info printfs) will be
2970 See also: doc/README.Modem
2972 Board initialization settings:
2973 ------------------------------
2975 During Initialization u-boot calls a number of board specific functions
2976 to allow the preparation of board specific prerequisites, e.g. pin setup
2977 before drivers are initialized. To enable these callbacks the
2978 following configuration macros have to be defined. Currently this is
2979 architecture specific, so please check arch/your_architecture/lib/board.c
2980 typically in board_init_f() and board_init_r().
2982 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2983 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2984 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2985 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2987 Configuration Settings:
2988 -----------------------
2990 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2991 undefine this when you're short of memory.
2993 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2994 width of the commands listed in the 'help' command output.
2996 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2997 prompt for user input.
2999 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3001 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3003 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3005 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3006 the application (usually a Linux kernel) when it is
3009 - CONFIG_SYS_BAUDRATE_TABLE:
3010 List of legal baudrate settings for this board.
3012 - CONFIG_SYS_CONSOLE_INFO_QUIET
3013 Suppress display of console information at boot.
3015 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3016 If the board specific function
3017 extern int overwrite_console (void);
3018 returns 1, the stdin, stderr and stdout are switched to the
3019 serial port, else the settings in the environment are used.
3021 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3022 Enable the call to overwrite_console().
3024 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3025 Enable overwrite of previous console environment settings.
3027 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3028 Begin and End addresses of the area used by the
3031 - CONFIG_SYS_ALT_MEMTEST:
3032 Enable an alternate, more extensive memory test.
3034 - CONFIG_SYS_MEMTEST_SCRATCH:
3035 Scratch address used by the alternate memory test
3036 You only need to set this if address zero isn't writeable
3038 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3039 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3040 this specified memory area will get subtracted from the top
3041 (end) of RAM and won't get "touched" at all by U-Boot. By
3042 fixing up gd->ram_size the Linux kernel should gets passed
3043 the now "corrected" memory size and won't touch it either.
3044 This should work for arch/ppc and arch/powerpc. Only Linux
3045 board ports in arch/powerpc with bootwrapper support that
3046 recalculate the memory size from the SDRAM controller setup
3047 will have to get fixed in Linux additionally.
3049 This option can be used as a workaround for the 440EPx/GRx
3050 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3053 WARNING: Please make sure that this value is a multiple of
3054 the Linux page size (normally 4k). If this is not the case,
3055 then the end address of the Linux memory will be located at a
3056 non page size aligned address and this could cause major
3059 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3060 Enable temporary baudrate change while serial download
3062 - CONFIG_SYS_SDRAM_BASE:
3063 Physical start address of SDRAM. _Must_ be 0 here.
3065 - CONFIG_SYS_MBIO_BASE:
3066 Physical start address of Motherboard I/O (if using a
3069 - CONFIG_SYS_FLASH_BASE:
3070 Physical start address of Flash memory.
3072 - CONFIG_SYS_MONITOR_BASE:
3073 Physical start address of boot monitor code (set by
3074 make config files to be same as the text base address
3075 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3076 CONFIG_SYS_FLASH_BASE when booting from flash.
3078 - CONFIG_SYS_MONITOR_LEN:
3079 Size of memory reserved for monitor code, used to
3080 determine _at_compile_time_ (!) if the environment is
3081 embedded within the U-Boot image, or in a separate
3084 - CONFIG_SYS_MALLOC_LEN:
3085 Size of DRAM reserved for malloc() use.
3087 - CONFIG_SYS_BOOTM_LEN:
3088 Normally compressed uImages are limited to an
3089 uncompressed size of 8 MBytes. If this is not enough,
3090 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3091 to adjust this setting to your needs.
3093 - CONFIG_SYS_BOOTMAPSZ:
3094 Maximum size of memory mapped by the startup code of
3095 the Linux kernel; all data that must be processed by
3096 the Linux kernel (bd_info, boot arguments, FDT blob if
3097 used) must be put below this limit, unless "bootm_low"
3098 enviroment variable is defined and non-zero. In such case
3099 all data for the Linux kernel must be between "bootm_low"
3100 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3101 variable "bootm_mapsize" will override the value of
3102 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3103 then the value in "bootm_size" will be used instead.
3105 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3106 Enable initrd_high functionality. If defined then the
3107 initrd_high feature is enabled and the bootm ramdisk subcommand
3110 - CONFIG_SYS_BOOT_GET_CMDLINE:
3111 Enables allocating and saving kernel cmdline in space between
3112 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3114 - CONFIG_SYS_BOOT_GET_KBD:
3115 Enables allocating and saving a kernel copy of the bd_info in
3116 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3118 - CONFIG_SYS_MAX_FLASH_BANKS:
3119 Max number of Flash memory banks
3121 - CONFIG_SYS_MAX_FLASH_SECT:
3122 Max number of sectors on a Flash chip
3124 - CONFIG_SYS_FLASH_ERASE_TOUT:
3125 Timeout for Flash erase operations (in ms)
3127 - CONFIG_SYS_FLASH_WRITE_TOUT:
3128 Timeout for Flash write operations (in ms)
3130 - CONFIG_SYS_FLASH_LOCK_TOUT
3131 Timeout for Flash set sector lock bit operation (in ms)
3133 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3134 Timeout for Flash clear lock bits operation (in ms)
3136 - CONFIG_SYS_FLASH_PROTECTION
3137 If defined, hardware flash sectors protection is used
3138 instead of U-Boot software protection.
3140 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3142 Enable TFTP transfers directly to flash memory;
3143 without this option such a download has to be
3144 performed in two steps: (1) download to RAM, and (2)
3145 copy from RAM to flash.
3147 The two-step approach is usually more reliable, since
3148 you can check if the download worked before you erase
3149 the flash, but in some situations (when system RAM is
3150 too limited to allow for a temporary copy of the
3151 downloaded image) this option may be very useful.
3153 - CONFIG_SYS_FLASH_CFI:
3154 Define if the flash driver uses extra elements in the
3155 common flash structure for storing flash geometry.
3157 - CONFIG_FLASH_CFI_DRIVER
3158 This option also enables the building of the cfi_flash driver
3159 in the drivers directory
3161 - CONFIG_FLASH_CFI_MTD
3162 This option enables the building of the cfi_mtd driver
3163 in the drivers directory. The driver exports CFI flash
3166 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3167 Use buffered writes to flash.
3169 - CONFIG_FLASH_SPANSION_S29WS_N
3170 s29ws-n MirrorBit flash has non-standard addresses for buffered
3173 - CONFIG_SYS_FLASH_QUIET_TEST
3174 If this option is defined, the common CFI flash doesn't
3175 print it's warning upon not recognized FLASH banks. This
3176 is useful, if some of the configured banks are only
3177 optionally available.
3179 - CONFIG_FLASH_SHOW_PROGRESS
3180 If defined (must be an integer), print out countdown
3181 digits and dots. Recommended value: 45 (9..1) for 80
3182 column displays, 15 (3..1) for 40 column displays.
3184 - CONFIG_SYS_RX_ETH_BUFFER:
3185 Defines the number of Ethernet receive buffers. On some
3186 Ethernet controllers it is recommended to set this value
3187 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3188 buffers can be full shortly after enabling the interface
3189 on high Ethernet traffic.
3190 Defaults to 4 if not defined.
3192 - CONFIG_ENV_MAX_ENTRIES
3194 Maximum number of entries in the hash table that is used
3195 internally to store the environment settings. The default
3196 setting is supposed to be generous and should work in most
3197 cases. This setting can be used to tune behaviour; see
3198 lib/hashtable.c for details.
3200 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3201 - CONFIG_ENV_FLAGS_LIST_STATIC
3202 Enable validation of the values given to enviroment variables when
3203 calling env set. Variables can be restricted to only decimal,
3204 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3205 the variables can also be restricted to IP address or MAC address.
3207 The format of the list is:
3208 type_attribute = [s|d|x|b|i|m]
3209 access_atribute = [a|r|o|c]
3210 attributes = type_attribute[access_atribute]
3211 entry = variable_name[:attributes]
3214 The type attributes are:
3215 s - String (default)
3218 b - Boolean ([1yYtT|0nNfF])
3222 The access attributes are:
3228 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3229 Define this to a list (string) to define the ".flags"
3230 envirnoment variable in the default or embedded environment.
3232 - CONFIG_ENV_FLAGS_LIST_STATIC
3233 Define this to a list (string) to define validation that
3234 should be done if an entry is not found in the ".flags"
3235 environment variable. To override a setting in the static
3236 list, simply add an entry for the same variable name to the
3239 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3240 If defined, don't allow the -f switch to env set override variable
3243 The following definitions that deal with the placement and management
3244 of environment data (variable area); in general, we support the
3245 following configurations:
3247 - CONFIG_BUILD_ENVCRC:
3249 Builds up envcrc with the target environment so that external utils
3250 may easily extract it and embed it in final U-Boot images.
3252 - CONFIG_ENV_IS_IN_FLASH:
3254 Define this if the environment is in flash memory.
3256 a) The environment occupies one whole flash sector, which is
3257 "embedded" in the text segment with the U-Boot code. This
3258 happens usually with "bottom boot sector" or "top boot
3259 sector" type flash chips, which have several smaller
3260 sectors at the start or the end. For instance, such a
3261 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3262 such a case you would place the environment in one of the
3263 4 kB sectors - with U-Boot code before and after it. With
3264 "top boot sector" type flash chips, you would put the
3265 environment in one of the last sectors, leaving a gap
3266 between U-Boot and the environment.
3268 - CONFIG_ENV_OFFSET:
3270 Offset of environment data (variable area) to the
3271 beginning of flash memory; for instance, with bottom boot
3272 type flash chips the second sector can be used: the offset
3273 for this sector is given here.
3275 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3279 This is just another way to specify the start address of
3280 the flash sector containing the environment (instead of
3283 - CONFIG_ENV_SECT_SIZE:
3285 Size of the sector containing the environment.
3288 b) Sometimes flash chips have few, equal sized, BIG sectors.
3289 In such a case you don't want to spend a whole sector for
3294 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3295 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3296 of this flash sector for the environment. This saves
3297 memory for the RAM copy of the environment.
3299 It may also save flash memory if you decide to use this
3300 when your environment is "embedded" within U-Boot code,
3301 since then the remainder of the flash sector could be used
3302 for U-Boot code. It should be pointed out that this is
3303 STRONGLY DISCOURAGED from a robustness point of view:
3304 updating the environment in flash makes it always
3305 necessary to erase the WHOLE sector. If something goes
3306 wrong before the contents has been restored from a copy in
3307 RAM, your target system will be dead.
3309 - CONFIG_ENV_ADDR_REDUND
3310 CONFIG_ENV_SIZE_REDUND
3312 These settings describe a second storage area used to hold
3313 a redundant copy of the environment data, so that there is
3314 a valid backup copy in case there is a power failure during
3315 a "saveenv" operation.
3317 BE CAREFUL! Any changes to the flash layout, and some changes to the
3318 source code will make it necessary to adapt <board>/u-boot.lds*
3322 - CONFIG_ENV_IS_IN_NVRAM:
3324 Define this if you have some non-volatile memory device
3325 (NVRAM, battery buffered SRAM) which you want to use for the
3331 These two #defines are used to determine the memory area you
3332 want to use for environment. It is assumed that this memory
3333 can just be read and written to, without any special
3336 BE CAREFUL! The first access to the environment happens quite early
3337 in U-Boot initalization (when we try to get the setting of for the
3338 console baudrate). You *MUST* have mapped your NVRAM area then, or
3341 Please note that even with NVRAM we still use a copy of the
3342 environment in RAM: we could work on NVRAM directly, but we want to
3343 keep settings there always unmodified except somebody uses "saveenv"
3344 to save the current settings.
3347 - CONFIG_ENV_IS_IN_EEPROM:
3349 Use this if you have an EEPROM or similar serial access
3350 device and a driver for it.
3352 - CONFIG_ENV_OFFSET:
3355 These two #defines specify the offset and size of the
3356 environment area within the total memory of your EEPROM.
3358 - CONFIG_SYS_I2C_EEPROM_ADDR:
3359 If defined, specified the chip address of the EEPROM device.
3360 The default address is zero.
3362 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3363 If defined, the number of bits used to address bytes in a
3364 single page in the EEPROM device. A 64 byte page, for example
3365 would require six bits.
3367 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3368 If defined, the number of milliseconds to delay between
3369 page writes. The default is zero milliseconds.
3371 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3372 The length in bytes of the EEPROM memory array address. Note
3373 that this is NOT the chip address length!
3375 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3376 EEPROM chips that implement "address overflow" are ones
3377 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3378 address and the extra bits end up in the "chip address" bit
3379 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3382 Note that we consider the length of the address field to
3383 still be one byte because the extra address bits are hidden
3384 in the chip address.
3386 - CONFIG_SYS_EEPROM_SIZE:
3387 The size in bytes of the EEPROM device.
3389 - CONFIG_ENV_EEPROM_IS_ON_I2C
3390 define this, if you have I2C and SPI activated, and your
3391 EEPROM, which holds the environment, is on the I2C bus.
3393 - CONFIG_I2C_ENV_EEPROM_BUS
3394 if you have an Environment on an EEPROM reached over
3395 I2C muxes, you can define here, how to reach this
3396 EEPROM. For example:
3398 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3400 EEPROM which holds the environment, is reached over
3401 a pca9547 i2c mux with address 0x70, channel 3.
3403 - CONFIG_ENV_IS_IN_DATAFLASH:
3405 Define this if you have a DataFlash memory device which you
3406 want to use for the environment.
3408 - CONFIG_ENV_OFFSET:
3412 These three #defines specify the offset and size of the
3413 environment area within the total memory of your DataFlash placed
3414 at the specified address.
3416 - CONFIG_ENV_IS_IN_REMOTE:
3418 Define this if you have a remote memory space which you
3419 want to use for the local device's environment.
3424 These two #defines specify the address and size of the
3425 environment area within the remote memory space. The
3426 local device can get the environment from remote memory
3427 space by SRIO or PCIE links.
3429 BE CAREFUL! For some special cases, the local device can not use
3430 "saveenv" command. For example, the local device will get the
3431 environment stored in a remote NOR flash by SRIO or PCIE link,
3432 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3434 - CONFIG_ENV_IS_IN_NAND:
3436 Define this if you have a NAND device which you want to use
3437 for the environment.
3439 - CONFIG_ENV_OFFSET:
3442 These two #defines specify the offset and size of the environment
3443 area within the first NAND device. CONFIG_ENV_OFFSET must be
3444 aligned to an erase block boundary.
3446 - CONFIG_ENV_OFFSET_REDUND (optional):
3448 This setting describes a second storage area of CONFIG_ENV_SIZE
3449 size used to hold a redundant copy of the environment data, so
3450 that there is a valid backup copy in case there is a power failure
3451 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3452 aligned to an erase block boundary.
3454 - CONFIG_ENV_RANGE (optional):
3456 Specifies the length of the region in which the environment
3457 can be written. This should be a multiple of the NAND device's
3458 block size. Specifying a range with more erase blocks than
3459 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3460 the range to be avoided.
3462 - CONFIG_ENV_OFFSET_OOB (optional):
3464 Enables support for dynamically retrieving the offset of the
3465 environment from block zero's out-of-band data. The
3466 "nand env.oob" command can be used to record this offset.
3467 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3468 using CONFIG_ENV_OFFSET_OOB.
3470 - CONFIG_NAND_ENV_DST
3472 Defines address in RAM to which the nand_spl code should copy the
3473 environment. If redundant environment is used, it will be copied to
3474 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3476 - CONFIG_SYS_SPI_INIT_OFFSET
3478 Defines offset to the initial SPI buffer area in DPRAM. The
3479 area is used at an early stage (ROM part) if the environment
3480 is configured to reside in the SPI EEPROM: We need a 520 byte
3481 scratch DPRAM area. It is used between the two initialization
3482 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3483 to be a good choice since it makes it far enough from the
3484 start of the data area as well as from the stack pointer.
3486 Please note that the environment is read-only until the monitor
3487 has been relocated to RAM and a RAM copy of the environment has been
3488 created; also, when using EEPROM you will have to use getenv_f()
3489 until then to read environment variables.
3491 The environment is protected by a CRC32 checksum. Before the monitor
3492 is relocated into RAM, as a result of a bad CRC you will be working
3493 with the compiled-in default environment - *silently*!!! [This is
3494 necessary, because the first environment variable we need is the
3495 "baudrate" setting for the console - if we have a bad CRC, we don't
3496 have any device yet where we could complain.]
3498 Note: once the monitor has been relocated, then it will complain if
3499 the default environment is used; a new CRC is computed as soon as you
3500 use the "saveenv" command to store a valid environment.
3502 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3503 Echo the inverted Ethernet link state to the fault LED.
3505 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3506 also needs to be defined.
3508 - CONFIG_SYS_FAULT_MII_ADDR:
3509 MII address of the PHY to check for the Ethernet link state.
3511 - CONFIG_NS16550_MIN_FUNCTIONS:
3512 Define this if you desire to only have use of the NS16550_init
3513 and NS16550_putc functions for the serial driver located at
3514 drivers/serial/ns16550.c. This option is useful for saving
3515 space for already greatly restricted images, including but not
3516 limited to NAND_SPL configurations.
3518 - CONFIG_DISPLAY_BOARDINFO
3519 Display information about the board that U-Boot is running on
3520 when U-Boot starts up. The board function checkboard() is called
3523 - CONFIG_DISPLAY_BOARDINFO_LATE
3524 Similar to the previous option, but display this information
3525 later, once stdio is running and output goes to the LCD, if
3528 Low Level (hardware related) configuration options:
3529 ---------------------------------------------------
3531 - CONFIG_SYS_CACHELINE_SIZE:
3532 Cache Line Size of the CPU.
3534 - CONFIG_SYS_DEFAULT_IMMR:
3535 Default address of the IMMR after system reset.
3537 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3538 and RPXsuper) to be able to adjust the position of
3539 the IMMR register after a reset.
3541 - CONFIG_SYS_CCSRBAR_DEFAULT:
3542 Default (power-on reset) physical address of CCSR on Freescale
3545 - CONFIG_SYS_CCSRBAR:
3546 Virtual address of CCSR. On a 32-bit build, this is typically
3547 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3549 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3550 for cross-platform code that uses that macro instead.
3552 - CONFIG_SYS_CCSRBAR_PHYS:
3553 Physical address of CCSR. CCSR can be relocated to a new
3554 physical address, if desired. In this case, this macro should
3555 be set to that address. Otherwise, it should be set to the
3556 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3557 is typically relocated on 36-bit builds. It is recommended
3558 that this macro be defined via the _HIGH and _LOW macros:
3560 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3561 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3563 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3564 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3565 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3566 used in assembly code, so it must not contain typecasts or
3567 integer size suffixes (e.g. "ULL").
3569 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3570 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3571 used in assembly code, so it must not contain typecasts or
3572 integer size suffixes (e.g. "ULL").
3574 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3575 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3576 forced to a value that ensures that CCSR is not relocated.
3578 - Floppy Disk Support:
3579 CONFIG_SYS_FDC_DRIVE_NUMBER
3581 the default drive number (default value 0)
3583 CONFIG_SYS_ISA_IO_STRIDE
3585 defines the spacing between FDC chipset registers
3588 CONFIG_SYS_ISA_IO_OFFSET
3590 defines the offset of register from address. It
3591 depends on which part of the data bus is connected to
3592 the FDC chipset. (default value 0)
3594 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3595 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3598 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3599 fdc_hw_init() is called at the beginning of the FDC
3600 setup. fdc_hw_init() must be provided by the board
3601 source code. It is used to make hardware dependant
3605 Most IDE controllers were designed to be connected with PCI
3606 interface. Only few of them were designed for AHB interface.
3607 When software is doing ATA command and data transfer to
3608 IDE devices through IDE-AHB controller, some additional
3609 registers accessing to these kind of IDE-AHB controller
3612 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3613 DO NOT CHANGE unless you know exactly what you're
3614 doing! (11-4) [MPC8xx/82xx systems only]
3616 - CONFIG_SYS_INIT_RAM_ADDR:
3618 Start address of memory area that can be used for
3619 initial data and stack; please note that this must be
3620 writable memory that is working WITHOUT special
3621 initialization, i. e. you CANNOT use normal RAM which
3622 will become available only after programming the
3623 memory controller and running certain initialization
3626 U-Boot uses the following memory types:
3627 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3628 - MPC824X: data cache
3629 - PPC4xx: data cache
3631 - CONFIG_SYS_GBL_DATA_OFFSET:
3633 Offset of the initial data structure in the memory
3634 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3635 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3636 data is located at the end of the available space
3637 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3638 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3639 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3640 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3643 On the MPC824X (or other systems that use the data
3644 cache for initial memory) the address chosen for
3645 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3646 point to an otherwise UNUSED address space between
3647 the top of RAM and the start of the PCI space.
3649 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3651 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3653 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3655 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3657 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3659 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3661 - CONFIG_SYS_OR_TIMING_SDRAM:
3664 - CONFIG_SYS_MAMR_PTA:
3665 periodic timer for refresh
3667 - CONFIG_SYS_DER: Debug Event Register (37-47)
3669 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3670 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3671 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3672 CONFIG_SYS_BR1_PRELIM:
3673 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3675 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3676 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3677 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3678 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3680 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3681 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3682 Machine Mode Register and Memory Periodic Timer
3683 Prescaler definitions (SDRAM timing)
3685 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3686 enable I2C microcode relocation patch (MPC8xx);
3687 define relocation offset in DPRAM [DSP2]
3689 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3690 enable SMC microcode relocation patch (MPC8xx);
3691 define relocation offset in DPRAM [SMC1]
3693 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3694 enable SPI microcode relocation patch (MPC8xx);
3695 define relocation offset in DPRAM [SCC4]
3697 - CONFIG_SYS_USE_OSCCLK:
3698 Use OSCM clock mode on MBX8xx board. Be careful,
3699 wrong setting might damage your board. Read
3700 doc/README.MBX before setting this variable!
3702 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3703 Offset of the bootmode word in DPRAM used by post
3704 (Power On Self Tests). This definition overrides
3705 #define'd default value in commproc.h resp.
3708 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3709 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3710 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3711 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3712 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3713 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3714 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3715 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3716 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3718 - CONFIG_PCI_DISABLE_PCIE:
3719 Disable PCI-Express on systems where it is supported but not
3722 - CONFIG_PCI_ENUM_ONLY
3723 Only scan through and get the devices on the busses.
3724 Don't do any setup work, presumably because someone or
3725 something has already done it, and we don't need to do it
3726 a second time. Useful for platforms that are pre-booted
3727 by coreboot or similar.
3730 Chip has SRIO or not
3733 Board has SRIO 1 port available
3736 Board has SRIO 2 port available
3738 - CONFIG_SYS_SRIOn_MEM_VIRT:
3739 Virtual Address of SRIO port 'n' memory region
3741 - CONFIG_SYS_SRIOn_MEM_PHYS:
3742 Physical Address of SRIO port 'n' memory region
3744 - CONFIG_SYS_SRIOn_MEM_SIZE:
3745 Size of SRIO port 'n' memory region
3747 - CONFIG_SYS_NDFC_16
3748 Defined to tell the NDFC that the NAND chip is using a
3751 - CONFIG_SYS_NDFC_EBC0_CFG
3752 Sets the EBC0_CFG register for the NDFC. If not defined
3753 a default value will be used.
3756 Get DDR timing information from an I2C EEPROM. Common
3757 with pluggable memory modules such as SODIMMs
3760 I2C address of the SPD EEPROM
3762 - CONFIG_SYS_SPD_BUS_NUM
3763 If SPD EEPROM is on an I2C bus other than the first
3764 one, specify here. Note that the value must resolve
3765 to something your driver can deal with.
3767 - CONFIG_SYS_DDR_RAW_TIMING
3768 Get DDR timing information from other than SPD. Common with
3769 soldered DDR chips onboard without SPD. DDR raw timing
3770 parameters are extracted from datasheet and hard-coded into
3771 header files or board specific files.
3773 - CONFIG_FSL_DDR_INTERACTIVE
3774 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3776 - CONFIG_SYS_83XX_DDR_USES_CS0
3777 Only for 83xx systems. If specified, then DDR should
3778 be configured using CS0 and CS1 instead of CS2 and CS3.
3780 - CONFIG_ETHER_ON_FEC[12]
3781 Define to enable FEC[12] on a 8xx series processor.
3783 - CONFIG_FEC[12]_PHY
3784 Define to the hardcoded PHY address which corresponds
3785 to the given FEC; i. e.
3786 #define CONFIG_FEC1_PHY 4
3787 means that the PHY with address 4 is connected to FEC1
3789 When set to -1, means to probe for first available.
3791 - CONFIG_FEC[12]_PHY_NORXERR
3792 The PHY does not have a RXERR line (RMII only).
3793 (so program the FEC to ignore it).
3796 Enable RMII mode for all FECs.
3797 Note that this is a global option, we can't
3798 have one FEC in standard MII mode and another in RMII mode.
3800 - CONFIG_CRC32_VERIFY
3801 Add a verify option to the crc32 command.
3804 => crc32 -v <address> <count> <crc32>
3806 Where address/count indicate a memory area
3807 and crc32 is the correct crc32 which the
3811 Add the "loopw" memory command. This only takes effect if
3812 the memory commands are activated globally (CONFIG_CMD_MEM).
3815 Add the "mdc" and "mwc" memory commands. These are cyclic
3820 This command will print 4 bytes (10,11,12,13) each 500 ms.
3822 => mwc.l 100 12345678 10
3823 This command will write 12345678 to address 100 all 10 ms.
3825 This only takes effect if the memory commands are activated
3826 globally (CONFIG_CMD_MEM).
3828 - CONFIG_SKIP_LOWLEVEL_INIT
3829 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3830 low level initializations (like setting up the memory
3831 controller) are omitted and/or U-Boot does not
3832 relocate itself into RAM.
3834 Normally this variable MUST NOT be defined. The only
3835 exception is when U-Boot is loaded (to RAM) by some
3836 other boot loader or by a debugger which performs
3837 these initializations itself.
3840 Modifies the behaviour of start.S when compiling a loader
3841 that is executed before the actual U-Boot. E.g. when
3842 compiling a NAND SPL.
3844 - CONFIG_ARCH_MAP_SYSMEM
3845 Generally U-Boot (and in particular the md command) uses
3846 effective address. It is therefore not necessary to regard
3847 U-Boot address as virtual addresses that need to be translated
3848 to physical addresses. However, sandbox requires this, since
3849 it maintains its own little RAM buffer which contains all
3850 addressable memory. This option causes some memory accesses
3851 to be mapped through map_sysmem() / unmap_sysmem().
3853 - CONFIG_USE_ARCH_MEMCPY
3854 CONFIG_USE_ARCH_MEMSET
3855 If these options are used a optimized version of memcpy/memset will
3856 be used if available. These functions may be faster under some
3857 conditions but may increase the binary size.
3859 - CONFIG_X86_RESET_VECTOR
3860 If defined, the x86 reset vector code is included. This is not
3861 needed when U-Boot is running from Coreboot.
3864 Freescale QE/FMAN Firmware Support:
3865 -----------------------------------
3867 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3868 loading of "firmware", which is encoded in the QE firmware binary format.
3869 This firmware often needs to be loaded during U-Boot booting, so macros
3870 are used to identify the storage device (NOR flash, SPI, etc) and the address
3873 - CONFIG_SYS_QE_FMAN_FW_ADDR
3874 The address in the storage device where the firmware is located. The
3875 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3878 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3879 The maximum possible size of the firmware. The firmware binary format
3880 has a field that specifies the actual size of the firmware, but it
3881 might not be possible to read any part of the firmware unless some
3882 local storage is allocated to hold the entire firmware first.
3884 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3885 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3886 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3887 virtual address in NOR flash.
3889 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3890 Specifies that QE/FMAN firmware is located in NAND flash.
3891 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3893 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3894 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3895 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3897 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3898 Specifies that QE/FMAN firmware is located on the primary SPI
3899 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3901 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3902 Specifies that QE/FMAN firmware is located in the remote (master)
3903 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3904 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3905 window->master inbound window->master LAW->the ucode address in
3906 master's memory space.
3908 Building the Software:
3909 ======================
3911 Building U-Boot has been tested in several native build environments
3912 and in many different cross environments. Of course we cannot support
3913 all possibly existing versions of cross development tools in all
3914 (potentially obsolete) versions. In case of tool chain problems we
3915 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3916 which is extensively used to build and test U-Boot.
3918 If you are not using a native environment, it is assumed that you
3919 have GNU cross compiling tools available in your path. In this case,
3920 you must set the environment variable CROSS_COMPILE in your shell.
3921 Note that no changes to the Makefile or any other source files are
3922 necessary. For example using the ELDK on a 4xx CPU, please enter:
3924 $ CROSS_COMPILE=ppc_4xx-
3925 $ export CROSS_COMPILE
3927 Note: If you wish to generate Windows versions of the utilities in
3928 the tools directory you can use the MinGW toolchain
3929 (http://www.mingw.org). Set your HOST tools to the MinGW
3930 toolchain and execute 'make tools'. For example:
3932 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3934 Binaries such as tools/mkimage.exe will be created which can
3935 be executed on computers running Windows.
3937 U-Boot is intended to be simple to build. After installing the
3938 sources you must configure U-Boot for one specific board type. This
3943 where "NAME_config" is the name of one of the existing configu-
3944 rations; see boards.cfg for supported names.
3946 Note: for some board special configuration names may exist; check if
3947 additional information is available from the board vendor; for
3948 instance, the TQM823L systems are available without (standard)
3949 or with LCD support. You can select such additional "features"
3950 when choosing the configuration, i. e.
3953 - will configure for a plain TQM823L, i. e. no LCD support
3955 make TQM823L_LCD_config
3956 - will configure for a TQM823L with U-Boot console on LCD
3961 Finally, type "make all", and you should get some working U-Boot
3962 images ready for download to / installation on your system:
3964 - "u-boot.bin" is a raw binary image
3965 - "u-boot" is an image in ELF binary format
3966 - "u-boot.srec" is in Motorola S-Record format
3968 By default the build is performed locally and the objects are saved
3969 in the source directory. One of the two methods can be used to change
3970 this behavior and build U-Boot to some external directory:
3972 1. Add O= to the make command line invocations:
3974 make O=/tmp/build distclean
3975 make O=/tmp/build NAME_config
3976 make O=/tmp/build all
3978 2. Set environment variable BUILD_DIR to point to the desired location:
3980 export BUILD_DIR=/tmp/build
3985 Note that the command line "O=" setting overrides the BUILD_DIR environment
3989 Please be aware that the Makefiles assume you are using GNU make, so
3990 for instance on NetBSD you might need to use "gmake" instead of
3994 If the system board that you have is not listed, then you will need
3995 to port U-Boot to your hardware platform. To do this, follow these
3998 1. Add a new configuration option for your board to the toplevel
3999 "boards.cfg" file, using the existing entries as examples.
4000 Follow the instructions there to keep the boards in order.
4001 2. Create a new directory to hold your board specific code. Add any
4002 files you need. In your board directory, you will need at least
4003 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4004 3. Create a new configuration file "include/configs/<board>.h" for
4006 3. If you're porting U-Boot to a new CPU, then also create a new
4007 directory to hold your CPU specific code. Add any files you need.
4008 4. Run "make <board>_config" with your new name.
4009 5. Type "make", and you should get a working "u-boot.srec" file
4010 to be installed on your target system.
4011 6. Debug and solve any problems that might arise.
4012 [Of course, this last step is much harder than it sounds.]
4015 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4016 ==============================================================
4018 If you have modified U-Boot sources (for instance added a new board
4019 or support for new devices, a new CPU, etc.) you are expected to
4020 provide feedback to the other developers. The feedback normally takes
4021 the form of a "patch", i. e. a context diff against a certain (latest
4022 official or latest in the git repository) version of U-Boot sources.
4024 But before you submit such a patch, please verify that your modifi-
4025 cation did not break existing code. At least make sure that *ALL* of
4026 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4027 just run the "MAKEALL" script, which will configure and build U-Boot
4028 for ALL supported system. Be warned, this will take a while. You can
4029 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4030 environment variable to the script, i. e. to use the ELDK cross tools
4033 CROSS_COMPILE=ppc_8xx- MAKEALL
4035 or to build on a native PowerPC system you can type
4037 CROSS_COMPILE=' ' MAKEALL
4039 When using the MAKEALL script, the default behaviour is to build
4040 U-Boot in the source directory. This location can be changed by
4041 setting the BUILD_DIR environment variable. Also, for each target
4042 built, the MAKEALL script saves two log files (<target>.ERR and
4043 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4044 location can be changed by setting the MAKEALL_LOGDIR environment
4045 variable. For example:
4047 export BUILD_DIR=/tmp/build
4048 export MAKEALL_LOGDIR=/tmp/log
4049 CROSS_COMPILE=ppc_8xx- MAKEALL
4051 With the above settings build objects are saved in the /tmp/build,
4052 log files are saved in the /tmp/log and the source tree remains clean
4053 during the whole build process.
4056 See also "U-Boot Porting Guide" below.
4059 Monitor Commands - Overview:
4060 ============================
4062 go - start application at address 'addr'
4063 run - run commands in an environment variable
4064 bootm - boot application image from memory
4065 bootp - boot image via network using BootP/TFTP protocol
4066 bootz - boot zImage from memory
4067 tftpboot- boot image via network using TFTP protocol
4068 and env variables "ipaddr" and "serverip"
4069 (and eventually "gatewayip")
4070 tftpput - upload a file via network using TFTP protocol
4071 rarpboot- boot image via network using RARP/TFTP protocol
4072 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4073 loads - load S-Record file over serial line
4074 loadb - load binary file over serial line (kermit mode)
4076 mm - memory modify (auto-incrementing)
4077 nm - memory modify (constant address)
4078 mw - memory write (fill)
4080 cmp - memory compare
4081 crc32 - checksum calculation
4082 i2c - I2C sub-system
4083 sspi - SPI utility commands
4084 base - print or set address offset
4085 printenv- print environment variables
4086 setenv - set environment variables
4087 saveenv - save environment variables to persistent storage
4088 protect - enable or disable FLASH write protection
4089 erase - erase FLASH memory
4090 flinfo - print FLASH memory information
4091 nand - NAND memory operations (see doc/README.nand)
4092 bdinfo - print Board Info structure
4093 iminfo - print header information for application image
4094 coninfo - print console devices and informations
4095 ide - IDE sub-system
4096 loop - infinite loop on address range
4097 loopw - infinite write loop on address range
4098 mtest - simple RAM test
4099 icache - enable or disable instruction cache
4100 dcache - enable or disable data cache
4101 reset - Perform RESET of the CPU
4102 echo - echo args to console
4103 version - print monitor version
4104 help - print online help
4105 ? - alias for 'help'
4108 Monitor Commands - Detailed Description:
4109 ========================================
4113 For now: just type "help <command>".
4116 Environment Variables:
4117 ======================
4119 U-Boot supports user configuration using Environment Variables which
4120 can be made persistent by saving to Flash memory.
4122 Environment Variables are set using "setenv", printed using
4123 "printenv", and saved to Flash using "saveenv". Using "setenv"
4124 without a value can be used to delete a variable from the
4125 environment. As long as you don't save the environment you are
4126 working with an in-memory copy. In case the Flash area containing the
4127 environment is erased by accident, a default environment is provided.
4129 Some configuration options can be set using Environment Variables.
4131 List of environment variables (most likely not complete):
4133 baudrate - see CONFIG_BAUDRATE
4135 bootdelay - see CONFIG_BOOTDELAY
4137 bootcmd - see CONFIG_BOOTCOMMAND
4139 bootargs - Boot arguments when booting an RTOS image
4141 bootfile - Name of the image to load with TFTP
4143 bootm_low - Memory range available for image processing in the bootm
4144 command can be restricted. This variable is given as
4145 a hexadecimal number and defines lowest address allowed
4146 for use by the bootm command. See also "bootm_size"
4147 environment variable. Address defined by "bootm_low" is
4148 also the base of the initial memory mapping for the Linux
4149 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4152 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4153 This variable is given as a hexadecimal number and it
4154 defines the size of the memory region starting at base
4155 address bootm_low that is accessible by the Linux kernel
4156 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4157 as the default value if it is defined, and bootm_size is
4160 bootm_size - Memory range available for image processing in the bootm
4161 command can be restricted. This variable is given as
4162 a hexadecimal number and defines the size of the region
4163 allowed for use by the bootm command. See also "bootm_low"
4164 environment variable.
4166 updatefile - Location of the software update file on a TFTP server, used
4167 by the automatic software update feature. Please refer to
4168 documentation in doc/README.update for more details.
4170 autoload - if set to "no" (any string beginning with 'n'),
4171 "bootp" will just load perform a lookup of the
4172 configuration from the BOOTP server, but not try to
4173 load any image using TFTP
4175 autostart - if set to "yes", an image loaded using the "bootp",
4176 "rarpboot", "tftpboot" or "diskboot" commands will
4177 be automatically started (by internally calling
4180 If set to "no", a standalone image passed to the
4181 "bootm" command will be copied to the load address
4182 (and eventually uncompressed), but NOT be started.
4183 This can be used to load and uncompress arbitrary
4186 fdt_high - if set this restricts the maximum address that the
4187 flattened device tree will be copied into upon boot.
4188 For example, if you have a system with 1 GB memory
4189 at physical address 0x10000000, while Linux kernel
4190 only recognizes the first 704 MB as low memory, you
4191 may need to set fdt_high as 0x3C000000 to have the
4192 device tree blob be copied to the maximum address
4193 of the 704 MB low memory, so that Linux kernel can
4194 access it during the boot procedure.
4196 If this is set to the special value 0xFFFFFFFF then
4197 the fdt will not be copied at all on boot. For this
4198 to work it must reside in writable memory, have
4199 sufficient padding on the end of it for u-boot to
4200 add the information it needs into it, and the memory
4201 must be accessible by the kernel.
4203 fdtcontroladdr- if set this is the address of the control flattened
4204 device tree used by U-Boot when CONFIG_OF_CONTROL is
4207 i2cfast - (PPC405GP|PPC405EP only)
4208 if set to 'y' configures Linux I2C driver for fast
4209 mode (400kHZ). This environment variable is used in
4210 initialization code. So, for changes to be effective
4211 it must be saved and board must be reset.
4213 initrd_high - restrict positioning of initrd images:
4214 If this variable is not set, initrd images will be
4215 copied to the highest possible address in RAM; this
4216 is usually what you want since it allows for
4217 maximum initrd size. If for some reason you want to
4218 make sure that the initrd image is loaded below the
4219 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4220 variable to a value of "no" or "off" or "0".
4221 Alternatively, you can set it to a maximum upper
4222 address to use (U-Boot will still check that it
4223 does not overwrite the U-Boot stack and data).
4225 For instance, when you have a system with 16 MB
4226 RAM, and want to reserve 4 MB from use by Linux,
4227 you can do this by adding "mem=12M" to the value of
4228 the "bootargs" variable. However, now you must make
4229 sure that the initrd image is placed in the first
4230 12 MB as well - this can be done with
4232 setenv initrd_high 00c00000
4234 If you set initrd_high to 0xFFFFFFFF, this is an
4235 indication to U-Boot that all addresses are legal
4236 for the Linux kernel, including addresses in flash
4237 memory. In this case U-Boot will NOT COPY the
4238 ramdisk at all. This may be useful to reduce the
4239 boot time on your system, but requires that this
4240 feature is supported by your Linux kernel.
4242 ipaddr - IP address; needed for tftpboot command
4244 loadaddr - Default load address for commands like "bootp",
4245 "rarpboot", "tftpboot", "loadb" or "diskboot"
4247 loads_echo - see CONFIG_LOADS_ECHO
4249 serverip - TFTP server IP address; needed for tftpboot command
4251 bootretry - see CONFIG_BOOT_RETRY_TIME
4253 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4255 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4257 ethprime - controls which interface is used first.
4259 ethact - controls which interface is currently active.
4260 For example you can do the following
4262 => setenv ethact FEC
4263 => ping 192.168.0.1 # traffic sent on FEC
4264 => setenv ethact SCC
4265 => ping 10.0.0.1 # traffic sent on SCC
4267 ethrotate - When set to "no" U-Boot does not go through all
4268 available network interfaces.
4269 It just stays at the currently selected interface.
4271 netretry - When set to "no" each network operation will
4272 either succeed or fail without retrying.
4273 When set to "once" the network operation will
4274 fail when all the available network interfaces
4275 are tried once without success.
4276 Useful on scripts which control the retry operation
4279 npe_ucode - set load address for the NPE microcode
4281 tftpsrcport - If this is set, the value is used for TFTP's
4284 tftpdstport - If this is set, the value is used for TFTP's UDP
4285 destination port instead of the Well Know Port 69.
4287 tftpblocksize - Block size to use for TFTP transfers; if not set,
4288 we use the TFTP server's default block size
4290 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4291 seconds, minimum value is 1000 = 1 second). Defines
4292 when a packet is considered to be lost so it has to
4293 be retransmitted. The default is 5000 = 5 seconds.
4294 Lowering this value may make downloads succeed
4295 faster in networks with high packet loss rates or
4296 with unreliable TFTP servers.
4298 vlan - When set to a value < 4095 the traffic over
4299 Ethernet is encapsulated/received over 802.1q
4302 The following image location variables contain the location of images
4303 used in booting. The "Image" column gives the role of the image and is
4304 not an environment variable name. The other columns are environment
4305 variable names. "File Name" gives the name of the file on a TFTP
4306 server, "RAM Address" gives the location in RAM the image will be
4307 loaded to, and "Flash Location" gives the image's address in NOR
4308 flash or offset in NAND flash.
4310 *Note* - these variables don't have to be defined for all boards, some
4311 boards currenlty use other variables for these purposes, and some
4312 boards use these variables for other purposes.
4314 Image File Name RAM Address Flash Location
4315 ----- --------- ----------- --------------
4316 u-boot u-boot u-boot_addr_r u-boot_addr
4317 Linux kernel bootfile kernel_addr_r kernel_addr
4318 device tree blob fdtfile fdt_addr_r fdt_addr
4319 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4321 The following environment variables may be used and automatically
4322 updated by the network boot commands ("bootp" and "rarpboot"),
4323 depending the information provided by your boot server:
4325 bootfile - see above
4326 dnsip - IP address of your Domain Name Server
4327 dnsip2 - IP address of your secondary Domain Name Server
4328 gatewayip - IP address of the Gateway (Router) to use
4329 hostname - Target hostname
4331 netmask - Subnet Mask
4332 rootpath - Pathname of the root filesystem on the NFS server
4333 serverip - see above
4336 There are two special Environment Variables:
4338 serial# - contains hardware identification information such
4339 as type string and/or serial number
4340 ethaddr - Ethernet address
4342 These variables can be set only once (usually during manufacturing of
4343 the board). U-Boot refuses to delete or overwrite these variables
4344 once they have been set once.
4347 Further special Environment Variables:
4349 ver - Contains the U-Boot version string as printed
4350 with the "version" command. This variable is
4351 readonly (see CONFIG_VERSION_VARIABLE).
4354 Please note that changes to some configuration parameters may take
4355 only effect after the next boot (yes, that's just like Windoze :-).
4358 Callback functions for environment variables:
4359 ---------------------------------------------
4361 For some environment variables, the behavior of u-boot needs to change
4362 when their values are changed. This functionailty allows functions to
4363 be associated with arbitrary variables. On creation, overwrite, or
4364 deletion, the callback will provide the opportunity for some side
4365 effect to happen or for the change to be rejected.
4367 The callbacks are named and associated with a function using the
4368 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4370 These callbacks are associated with variables in one of two ways. The
4371 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4372 in the board configuration to a string that defines a list of
4373 associations. The list must be in the following format:
4375 entry = variable_name[:callback_name]
4378 If the callback name is not specified, then the callback is deleted.
4379 Spaces are also allowed anywhere in the list.
4381 Callbacks can also be associated by defining the ".callbacks" variable
4382 with the same list format above. Any association in ".callbacks" will
4383 override any association in the static list. You can define
4384 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4385 ".callbacks" envirnoment variable in the default or embedded environment.
4388 Command Line Parsing:
4389 =====================
4391 There are two different command line parsers available with U-Boot:
4392 the old "simple" one, and the much more powerful "hush" shell:
4394 Old, simple command line parser:
4395 --------------------------------
4397 - supports environment variables (through setenv / saveenv commands)
4398 - several commands on one line, separated by ';'
4399 - variable substitution using "... ${name} ..." syntax
4400 - special characters ('$', ';') can be escaped by prefixing with '\',
4402 setenv bootcmd bootm \${address}
4403 - You can also escape text by enclosing in single apostrophes, for example:
4404 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4409 - similar to Bourne shell, with control structures like
4410 if...then...else...fi, for...do...done; while...do...done,
4411 until...do...done, ...
4412 - supports environment ("global") variables (through setenv / saveenv
4413 commands) and local shell variables (through standard shell syntax
4414 "name=value"); only environment variables can be used with "run"
4420 (1) If a command line (or an environment variable executed by a "run"
4421 command) contains several commands separated by semicolon, and
4422 one of these commands fails, then the remaining commands will be
4425 (2) If you execute several variables with one call to run (i. e.
4426 calling run with a list of variables as arguments), any failing
4427 command will cause "run" to terminate, i. e. the remaining
4428 variables are not executed.
4430 Note for Redundant Ethernet Interfaces:
4431 =======================================
4433 Some boards come with redundant Ethernet interfaces; U-Boot supports
4434 such configurations and is capable of automatic selection of a
4435 "working" interface when needed. MAC assignment works as follows:
4437 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4438 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4439 "eth1addr" (=>eth1), "eth2addr", ...
4441 If the network interface stores some valid MAC address (for instance
4442 in SROM), this is used as default address if there is NO correspon-
4443 ding setting in the environment; if the corresponding environment
4444 variable is set, this overrides the settings in the card; that means:
4446 o If the SROM has a valid MAC address, and there is no address in the
4447 environment, the SROM's address is used.
4449 o If there is no valid address in the SROM, and a definition in the
4450 environment exists, then the value from the environment variable is
4453 o If both the SROM and the environment contain a MAC address, and
4454 both addresses are the same, this MAC address is used.
4456 o If both the SROM and the environment contain a MAC address, and the
4457 addresses differ, the value from the environment is used and a
4460 o If neither SROM nor the environment contain a MAC address, an error
4463 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4464 will be programmed into hardware as part of the initialization process. This
4465 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4466 The naming convention is as follows:
4467 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4472 U-Boot is capable of booting (and performing other auxiliary operations on)
4473 images in two formats:
4475 New uImage format (FIT)
4476 -----------------------
4478 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4479 to Flattened Device Tree). It allows the use of images with multiple
4480 components (several kernels, ramdisks, etc.), with contents protected by
4481 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4487 Old image format is based on binary files which can be basically anything,
4488 preceded by a special header; see the definitions in include/image.h for
4489 details; basically, the header defines the following image properties:
4491 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4492 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4493 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4494 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4496 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4497 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4498 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4499 * Compression Type (uncompressed, gzip, bzip2)
4505 The header is marked by a special Magic Number, and both the header
4506 and the data portions of the image are secured against corruption by
4513 Although U-Boot should support any OS or standalone application
4514 easily, the main focus has always been on Linux during the design of
4517 U-Boot includes many features that so far have been part of some
4518 special "boot loader" code within the Linux kernel. Also, any
4519 "initrd" images to be used are no longer part of one big Linux image;
4520 instead, kernel and "initrd" are separate images. This implementation
4521 serves several purposes:
4523 - the same features can be used for other OS or standalone
4524 applications (for instance: using compressed images to reduce the
4525 Flash memory footprint)
4527 - it becomes much easier to port new Linux kernel versions because
4528 lots of low-level, hardware dependent stuff are done by U-Boot
4530 - the same Linux kernel image can now be used with different "initrd"
4531 images; of course this also means that different kernel images can
4532 be run with the same "initrd". This makes testing easier (you don't
4533 have to build a new "zImage.initrd" Linux image when you just
4534 change a file in your "initrd"). Also, a field-upgrade of the
4535 software is easier now.
4541 Porting Linux to U-Boot based systems:
4542 ---------------------------------------
4544 U-Boot cannot save you from doing all the necessary modifications to
4545 configure the Linux device drivers for use with your target hardware
4546 (no, we don't intend to provide a full virtual machine interface to
4549 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4551 Just make sure your machine specific header file (for instance
4552 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4553 Information structure as we define in include/asm-<arch>/u-boot.h,
4554 and make sure that your definition of IMAP_ADDR uses the same value
4555 as your U-Boot configuration in CONFIG_SYS_IMMR.
4558 Configuring the Linux kernel:
4559 -----------------------------
4561 No specific requirements for U-Boot. Make sure you have some root
4562 device (initial ramdisk, NFS) for your target system.
4565 Building a Linux Image:
4566 -----------------------
4568 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4569 not used. If you use recent kernel source, a new build target
4570 "uImage" will exist which automatically builds an image usable by
4571 U-Boot. Most older kernels also have support for a "pImage" target,
4572 which was introduced for our predecessor project PPCBoot and uses a
4573 100% compatible format.
4582 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4583 encapsulate a compressed Linux kernel image with header information,
4584 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4586 * build a standard "vmlinux" kernel image (in ELF binary format):
4588 * convert the kernel into a raw binary image:
4590 ${CROSS_COMPILE}-objcopy -O binary \
4591 -R .note -R .comment \
4592 -S vmlinux linux.bin
4594 * compress the binary image:
4598 * package compressed binary image for U-Boot:
4600 mkimage -A ppc -O linux -T kernel -C gzip \
4601 -a 0 -e 0 -n "Linux Kernel Image" \
4602 -d linux.bin.gz uImage
4605 The "mkimage" tool can also be used to create ramdisk images for use
4606 with U-Boot, either separated from the Linux kernel image, or
4607 combined into one file. "mkimage" encapsulates the images with a 64
4608 byte header containing information about target architecture,
4609 operating system, image type, compression method, entry points, time
4610 stamp, CRC32 checksums, etc.
4612 "mkimage" can be called in two ways: to verify existing images and
4613 print the header information, or to build new images.
4615 In the first form (with "-l" option) mkimage lists the information
4616 contained in the header of an existing U-Boot image; this includes
4617 checksum verification:
4619 tools/mkimage -l image
4620 -l ==> list image header information
4622 The second form (with "-d" option) is used to build a U-Boot image
4623 from a "data file" which is used as image payload:
4625 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4626 -n name -d data_file image
4627 -A ==> set architecture to 'arch'
4628 -O ==> set operating system to 'os'
4629 -T ==> set image type to 'type'
4630 -C ==> set compression type 'comp'
4631 -a ==> set load address to 'addr' (hex)
4632 -e ==> set entry point to 'ep' (hex)
4633 -n ==> set image name to 'name'
4634 -d ==> use image data from 'datafile'
4636 Right now, all Linux kernels for PowerPC systems use the same load
4637 address (0x00000000), but the entry point address depends on the
4640 - 2.2.x kernels have the entry point at 0x0000000C,
4641 - 2.3.x and later kernels have the entry point at 0x00000000.
4643 So a typical call to build a U-Boot image would read:
4645 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4646 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4647 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4648 > examples/uImage.TQM850L
4649 Image Name: 2.4.4 kernel for TQM850L
4650 Created: Wed Jul 19 02:34:59 2000
4651 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4652 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4653 Load Address: 0x00000000
4654 Entry Point: 0x00000000
4656 To verify the contents of the image (or check for corruption):
4658 -> tools/mkimage -l examples/uImage.TQM850L
4659 Image Name: 2.4.4 kernel for TQM850L
4660 Created: Wed Jul 19 02:34:59 2000
4661 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4662 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4663 Load Address: 0x00000000
4664 Entry Point: 0x00000000
4666 NOTE: for embedded systems where boot time is critical you can trade
4667 speed for memory and install an UNCOMPRESSED image instead: this
4668 needs more space in Flash, but boots much faster since it does not
4669 need to be uncompressed:
4671 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4672 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4673 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4674 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4675 > examples/uImage.TQM850L-uncompressed
4676 Image Name: 2.4.4 kernel for TQM850L
4677 Created: Wed Jul 19 02:34:59 2000
4678 Image Type: PowerPC Linux Kernel Image (uncompressed)
4679 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4680 Load Address: 0x00000000
4681 Entry Point: 0x00000000
4684 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4685 when your kernel is intended to use an initial ramdisk:
4687 -> tools/mkimage -n 'Simple Ramdisk Image' \
4688 > -A ppc -O linux -T ramdisk -C gzip \
4689 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4690 Image Name: Simple Ramdisk Image
4691 Created: Wed Jan 12 14:01:50 2000
4692 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4693 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4694 Load Address: 0x00000000
4695 Entry Point: 0x00000000
4698 Installing a Linux Image:
4699 -------------------------
4701 To downloading a U-Boot image over the serial (console) interface,
4702 you must convert the image to S-Record format:
4704 objcopy -I binary -O srec examples/image examples/image.srec
4706 The 'objcopy' does not understand the information in the U-Boot
4707 image header, so the resulting S-Record file will be relative to
4708 address 0x00000000. To load it to a given address, you need to
4709 specify the target address as 'offset' parameter with the 'loads'
4712 Example: install the image to address 0x40100000 (which on the
4713 TQM8xxL is in the first Flash bank):
4715 => erase 40100000 401FFFFF
4721 ## Ready for S-Record download ...
4722 ~>examples/image.srec
4723 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4725 15989 15990 15991 15992
4726 [file transfer complete]
4728 ## Start Addr = 0x00000000
4731 You can check the success of the download using the 'iminfo' command;
4732 this includes a checksum verification so you can be sure no data
4733 corruption happened:
4737 ## Checking Image at 40100000 ...
4738 Image Name: 2.2.13 for initrd on TQM850L
4739 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4740 Data Size: 335725 Bytes = 327 kB = 0 MB
4741 Load Address: 00000000
4742 Entry Point: 0000000c
4743 Verifying Checksum ... OK
4749 The "bootm" command is used to boot an application that is stored in
4750 memory (RAM or Flash). In case of a Linux kernel image, the contents
4751 of the "bootargs" environment variable is passed to the kernel as
4752 parameters. You can check and modify this variable using the
4753 "printenv" and "setenv" commands:
4756 => printenv bootargs
4757 bootargs=root=/dev/ram
4759 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4761 => printenv bootargs
4762 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4765 ## Booting Linux kernel at 40020000 ...
4766 Image Name: 2.2.13 for NFS on TQM850L
4767 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4768 Data Size: 381681 Bytes = 372 kB = 0 MB
4769 Load Address: 00000000
4770 Entry Point: 0000000c
4771 Verifying Checksum ... OK
4772 Uncompressing Kernel Image ... OK
4773 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
4774 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4775 time_init: decrementer frequency = 187500000/60
4776 Calibrating delay loop... 49.77 BogoMIPS
4777 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4780 If you want to boot a Linux kernel with initial RAM disk, you pass
4781 the memory addresses of both the kernel and the initrd image (PPBCOOT
4782 format!) to the "bootm" command:
4784 => imi 40100000 40200000
4786 ## Checking Image at 40100000 ...
4787 Image Name: 2.2.13 for initrd on TQM850L
4788 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4789 Data Size: 335725 Bytes = 327 kB = 0 MB
4790 Load Address: 00000000
4791 Entry Point: 0000000c
4792 Verifying Checksum ... OK
4794 ## Checking Image at 40200000 ...
4795 Image Name: Simple Ramdisk Image
4796 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4797 Data Size: 566530 Bytes = 553 kB = 0 MB
4798 Load Address: 00000000
4799 Entry Point: 00000000
4800 Verifying Checksum ... OK
4802 => bootm 40100000 40200000
4803 ## Booting Linux kernel at 40100000 ...
4804 Image Name: 2.2.13 for initrd on TQM850L
4805 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4806 Data Size: 335725 Bytes = 327 kB = 0 MB
4807 Load Address: 00000000
4808 Entry Point: 0000000c
4809 Verifying Checksum ... OK
4810 Uncompressing Kernel Image ... OK
4811 ## Loading RAMDisk Image at 40200000 ...
4812 Image Name: Simple Ramdisk Image
4813 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4814 Data Size: 566530 Bytes = 553 kB = 0 MB
4815 Load Address: 00000000
4816 Entry Point: 00000000
4817 Verifying Checksum ... OK
4818 Loading Ramdisk ... OK
4819 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
4820 Boot arguments: root=/dev/ram
4821 time_init: decrementer frequency = 187500000/60
4822 Calibrating delay loop... 49.77 BogoMIPS
4824 RAMDISK: Compressed image found at block 0
4825 VFS: Mounted root (ext2 filesystem).
4829 Boot Linux and pass a flat device tree:
4832 First, U-Boot must be compiled with the appropriate defines. See the section
4833 titled "Linux Kernel Interface" above for a more in depth explanation. The
4834 following is an example of how to start a kernel and pass an updated
4840 oft=oftrees/mpc8540ads.dtb
4841 => tftp $oftaddr $oft
4842 Speed: 1000, full duplex
4844 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4845 Filename 'oftrees/mpc8540ads.dtb'.
4846 Load address: 0x300000
4849 Bytes transferred = 4106 (100a hex)
4850 => tftp $loadaddr $bootfile
4851 Speed: 1000, full duplex
4853 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4855 Load address: 0x200000
4856 Loading:############
4858 Bytes transferred = 1029407 (fb51f hex)
4863 => bootm $loadaddr - $oftaddr
4864 ## Booting image at 00200000 ...
4865 Image Name: Linux-2.6.17-dirty
4866 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4867 Data Size: 1029343 Bytes = 1005.2 kB
4868 Load Address: 00000000
4869 Entry Point: 00000000
4870 Verifying Checksum ... OK
4871 Uncompressing Kernel Image ... OK
4872 Booting using flat device tree at 0x300000
4873 Using MPC85xx ADS machine description
4874 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4878 More About U-Boot Image Types:
4879 ------------------------------
4881 U-Boot supports the following image types:
4883 "Standalone Programs" are directly runnable in the environment
4884 provided by U-Boot; it is expected that (if they behave
4885 well) you can continue to work in U-Boot after return from
4886 the Standalone Program.
4887 "OS Kernel Images" are usually images of some Embedded OS which
4888 will take over control completely. Usually these programs
4889 will install their own set of exception handlers, device
4890 drivers, set up the MMU, etc. - this means, that you cannot
4891 expect to re-enter U-Boot except by resetting the CPU.
4892 "RAMDisk Images" are more or less just data blocks, and their
4893 parameters (address, size) are passed to an OS kernel that is
4895 "Multi-File Images" contain several images, typically an OS
4896 (Linux) kernel image and one or more data images like
4897 RAMDisks. This construct is useful for instance when you want
4898 to boot over the network using BOOTP etc., where the boot
4899 server provides just a single image file, but you want to get
4900 for instance an OS kernel and a RAMDisk image.
4902 "Multi-File Images" start with a list of image sizes, each
4903 image size (in bytes) specified by an "uint32_t" in network
4904 byte order. This list is terminated by an "(uint32_t)0".
4905 Immediately after the terminating 0 follow the images, one by
4906 one, all aligned on "uint32_t" boundaries (size rounded up to
4907 a multiple of 4 bytes).
4909 "Firmware Images" are binary images containing firmware (like
4910 U-Boot or FPGA images) which usually will be programmed to
4913 "Script files" are command sequences that will be executed by
4914 U-Boot's command interpreter; this feature is especially
4915 useful when you configure U-Boot to use a real shell (hush)
4916 as command interpreter.
4918 Booting the Linux zImage:
4919 -------------------------
4921 On some platforms, it's possible to boot Linux zImage. This is done
4922 using the "bootz" command. The syntax of "bootz" command is the same
4923 as the syntax of "bootm" command.
4925 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4926 kernel with raw initrd images. The syntax is slightly different, the
4927 address of the initrd must be augmented by it's size, in the following
4928 format: "<initrd addres>:<initrd size>".
4934 One of the features of U-Boot is that you can dynamically load and
4935 run "standalone" applications, which can use some resources of
4936 U-Boot like console I/O functions or interrupt services.
4938 Two simple examples are included with the sources:
4943 'examples/hello_world.c' contains a small "Hello World" Demo
4944 application; it is automatically compiled when you build U-Boot.
4945 It's configured to run at address 0x00040004, so you can play with it
4949 ## Ready for S-Record download ...
4950 ~>examples/hello_world.srec
4951 1 2 3 4 5 6 7 8 9 10 11 ...
4952 [file transfer complete]
4954 ## Start Addr = 0x00040004
4956 => go 40004 Hello World! This is a test.
4957 ## Starting application at 0x00040004 ...
4968 Hit any key to exit ...
4970 ## Application terminated, rc = 0x0
4972 Another example, which demonstrates how to register a CPM interrupt
4973 handler with the U-Boot code, can be found in 'examples/timer.c'.
4974 Here, a CPM timer is set up to generate an interrupt every second.
4975 The interrupt service routine is trivial, just printing a '.'
4976 character, but this is just a demo program. The application can be
4977 controlled by the following keys:
4979 ? - print current values og the CPM Timer registers
4980 b - enable interrupts and start timer
4981 e - stop timer and disable interrupts
4982 q - quit application
4985 ## Ready for S-Record download ...
4986 ~>examples/timer.srec
4987 1 2 3 4 5 6 7 8 9 10 11 ...
4988 [file transfer complete]
4990 ## Start Addr = 0x00040004
4993 ## Starting application at 0x00040004 ...
4996 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4999 [q, b, e, ?] Set interval 1000000 us
5002 [q, b, e, ?] ........
5003 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5006 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5009 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5012 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5014 [q, b, e, ?] ...Stopping timer
5016 [q, b, e, ?] ## Application terminated, rc = 0x0
5022 Over time, many people have reported problems when trying to use the
5023 "minicom" terminal emulation program for serial download. I (wd)
5024 consider minicom to be broken, and recommend not to use it. Under
5025 Unix, I recommend to use C-Kermit for general purpose use (and
5026 especially for kermit binary protocol download ("loadb" command), and
5027 use "cu" for S-Record download ("loads" command). See
5028 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5029 for help with kermit.
5032 Nevertheless, if you absolutely want to use it try adding this
5033 configuration to your "File transfer protocols" section:
5035 Name Program Name U/D FullScr IO-Red. Multi
5036 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5037 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5043 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5044 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5046 Building requires a cross environment; it is known to work on
5047 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5048 need gmake since the Makefiles are not compatible with BSD make).
5049 Note that the cross-powerpc package does not install include files;
5050 attempting to build U-Boot will fail because <machine/ansi.h> is
5051 missing. This file has to be installed and patched manually:
5053 # cd /usr/pkg/cross/powerpc-netbsd/include
5055 # ln -s powerpc machine
5056 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5057 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5059 Native builds *don't* work due to incompatibilities between native
5060 and U-Boot include files.
5062 Booting assumes that (the first part of) the image booted is a
5063 stage-2 loader which in turn loads and then invokes the kernel
5064 proper. Loader sources will eventually appear in the NetBSD source
5065 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5066 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5069 Implementation Internals:
5070 =========================
5072 The following is not intended to be a complete description of every
5073 implementation detail. However, it should help to understand the
5074 inner workings of U-Boot and make it easier to port it to custom
5078 Initial Stack, Global Data:
5079 ---------------------------
5081 The implementation of U-Boot is complicated by the fact that U-Boot
5082 starts running out of ROM (flash memory), usually without access to
5083 system RAM (because the memory controller is not initialized yet).
5084 This means that we don't have writable Data or BSS segments, and BSS
5085 is not initialized as zero. To be able to get a C environment working
5086 at all, we have to allocate at least a minimal stack. Implementation
5087 options for this are defined and restricted by the CPU used: Some CPU
5088 models provide on-chip memory (like the IMMR area on MPC8xx and
5089 MPC826x processors), on others (parts of) the data cache can be
5090 locked as (mis-) used as memory, etc.
5092 Chris Hallinan posted a good summary of these issues to the
5093 U-Boot mailing list:
5095 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5096 From: "Chris Hallinan" <clh@net1plus.com>
5097 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5100 Correct me if I'm wrong, folks, but the way I understand it
5101 is this: Using DCACHE as initial RAM for Stack, etc, does not
5102 require any physical RAM backing up the cache. The cleverness
5103 is that the cache is being used as a temporary supply of
5104 necessary storage before the SDRAM controller is setup. It's
5105 beyond the scope of this list to explain the details, but you
5106 can see how this works by studying the cache architecture and
5107 operation in the architecture and processor-specific manuals.
5109 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5110 is another option for the system designer to use as an
5111 initial stack/RAM area prior to SDRAM being available. Either
5112 option should work for you. Using CS 4 should be fine if your
5113 board designers haven't used it for something that would
5114 cause you grief during the initial boot! It is frequently not
5117 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5118 with your processor/board/system design. The default value
5119 you will find in any recent u-boot distribution in
5120 walnut.h should work for you. I'd set it to a value larger
5121 than your SDRAM module. If you have a 64MB SDRAM module, set
5122 it above 400_0000. Just make sure your board has no resources
5123 that are supposed to respond to that address! That code in
5124 start.S has been around a while and should work as is when
5125 you get the config right.
5130 It is essential to remember this, since it has some impact on the C
5131 code for the initialization procedures:
5133 * Initialized global data (data segment) is read-only. Do not attempt
5136 * Do not use any uninitialized global data (or implicitely initialized
5137 as zero data - BSS segment) at all - this is undefined, initiali-
5138 zation is performed later (when relocating to RAM).
5140 * Stack space is very limited. Avoid big data buffers or things like
5143 Having only the stack as writable memory limits means we cannot use
5144 normal global data to share information beween the code. But it
5145 turned out that the implementation of U-Boot can be greatly
5146 simplified by making a global data structure (gd_t) available to all
5147 functions. We could pass a pointer to this data as argument to _all_
5148 functions, but this would bloat the code. Instead we use a feature of
5149 the GCC compiler (Global Register Variables) to share the data: we
5150 place a pointer (gd) to the global data into a register which we
5151 reserve for this purpose.
5153 When choosing a register for such a purpose we are restricted by the
5154 relevant (E)ABI specifications for the current architecture, and by
5155 GCC's implementation.
5157 For PowerPC, the following registers have specific use:
5159 R2: reserved for system use
5160 R3-R4: parameter passing and return values
5161 R5-R10: parameter passing
5162 R13: small data area pointer
5166 (U-Boot also uses R12 as internal GOT pointer. r12
5167 is a volatile register so r12 needs to be reset when
5168 going back and forth between asm and C)
5170 ==> U-Boot will use R2 to hold a pointer to the global data
5172 Note: on PPC, we could use a static initializer (since the
5173 address of the global data structure is known at compile time),
5174 but it turned out that reserving a register results in somewhat
5175 smaller code - although the code savings are not that big (on
5176 average for all boards 752 bytes for the whole U-Boot image,
5177 624 text + 127 data).
5179 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5180 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5182 ==> U-Boot will use P3 to hold a pointer to the global data
5184 On ARM, the following registers are used:
5186 R0: function argument word/integer result
5187 R1-R3: function argument word
5189 R10: stack limit (used only if stack checking if enabled)
5190 R11: argument (frame) pointer
5191 R12: temporary workspace
5194 R15: program counter
5196 ==> U-Boot will use R8 to hold a pointer to the global data
5198 On Nios II, the ABI is documented here:
5199 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5201 ==> U-Boot will use gp to hold a pointer to the global data
5203 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5204 to access small data sections, so gp is free.
5206 On NDS32, the following registers are used:
5208 R0-R1: argument/return
5210 R15: temporary register for assembler
5211 R16: trampoline register
5212 R28: frame pointer (FP)
5213 R29: global pointer (GP)
5214 R30: link register (LP)
5215 R31: stack pointer (SP)
5216 PC: program counter (PC)
5218 ==> U-Boot will use R10 to hold a pointer to the global data
5220 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5221 or current versions of GCC may "optimize" the code too much.
5226 U-Boot runs in system state and uses physical addresses, i.e. the
5227 MMU is not used either for address mapping nor for memory protection.
5229 The available memory is mapped to fixed addresses using the memory
5230 controller. In this process, a contiguous block is formed for each
5231 memory type (Flash, SDRAM, SRAM), even when it consists of several
5232 physical memory banks.
5234 U-Boot is installed in the first 128 kB of the first Flash bank (on
5235 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5236 booting and sizing and initializing DRAM, the code relocates itself
5237 to the upper end of DRAM. Immediately below the U-Boot code some
5238 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5239 configuration setting]. Below that, a structure with global Board
5240 Info data is placed, followed by the stack (growing downward).
5242 Additionally, some exception handler code is copied to the low 8 kB
5243 of DRAM (0x00000000 ... 0x00001FFF).
5245 So a typical memory configuration with 16 MB of DRAM could look like
5248 0x0000 0000 Exception Vector code
5251 0x0000 2000 Free for Application Use
5257 0x00FB FF20 Monitor Stack (Growing downward)
5258 0x00FB FFAC Board Info Data and permanent copy of global data
5259 0x00FC 0000 Malloc Arena
5262 0x00FE 0000 RAM Copy of Monitor Code
5263 ... eventually: LCD or video framebuffer
5264 ... eventually: pRAM (Protected RAM - unchanged by reset)
5265 0x00FF FFFF [End of RAM]
5268 System Initialization:
5269 ----------------------
5271 In the reset configuration, U-Boot starts at the reset entry point
5272 (on most PowerPC systems at address 0x00000100). Because of the reset
5273 configuration for CS0# this is a mirror of the onboard Flash memory.
5274 To be able to re-map memory U-Boot then jumps to its link address.
5275 To be able to implement the initialization code in C, a (small!)
5276 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5277 which provide such a feature like MPC8xx or MPC8260), or in a locked
5278 part of the data cache. After that, U-Boot initializes the CPU core,
5279 the caches and the SIU.
5281 Next, all (potentially) available memory banks are mapped using a
5282 preliminary mapping. For example, we put them on 512 MB boundaries
5283 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5284 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5285 programmed for SDRAM access. Using the temporary configuration, a
5286 simple memory test is run that determines the size of the SDRAM
5289 When there is more than one SDRAM bank, and the banks are of
5290 different size, the largest is mapped first. For equal size, the first
5291 bank (CS2#) is mapped first. The first mapping is always for address
5292 0x00000000, with any additional banks following immediately to create
5293 contiguous memory starting from 0.
5295 Then, the monitor installs itself at the upper end of the SDRAM area
5296 and allocates memory for use by malloc() and for the global Board
5297 Info data; also, the exception vector code is copied to the low RAM
5298 pages, and the final stack is set up.
5300 Only after this relocation will you have a "normal" C environment;
5301 until that you are restricted in several ways, mostly because you are
5302 running from ROM, and because the code will have to be relocated to a
5306 U-Boot Porting Guide:
5307 ----------------------
5309 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5313 int main(int argc, char *argv[])
5315 sighandler_t no_more_time;
5317 signal(SIGALRM, no_more_time);
5318 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5320 if (available_money > available_manpower) {
5321 Pay consultant to port U-Boot;
5325 Download latest U-Boot source;
5327 Subscribe to u-boot mailing list;
5330 email("Hi, I am new to U-Boot, how do I get started?");
5333 Read the README file in the top level directory;
5334 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5335 Read applicable doc/*.README;
5336 Read the source, Luke;
5337 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5340 if (available_money > toLocalCurrency ($2500))
5343 Add a lot of aggravation and time;
5345 if (a similar board exists) { /* hopefully... */
5346 cp -a board/<similar> board/<myboard>
5347 cp include/configs/<similar>.h include/configs/<myboard>.h
5349 Create your own board support subdirectory;
5350 Create your own board include/configs/<myboard>.h file;
5352 Edit new board/<myboard> files
5353 Edit new include/configs/<myboard>.h
5358 Add / modify source code;
5362 email("Hi, I am having problems...");
5364 Send patch file to the U-Boot email list;
5365 if (reasonable critiques)
5366 Incorporate improvements from email list code review;
5368 Defend code as written;
5374 void no_more_time (int sig)
5383 All contributions to U-Boot should conform to the Linux kernel
5384 coding style; see the file "Documentation/CodingStyle" and the script
5385 "scripts/Lindent" in your Linux kernel source directory.
5387 Source files originating from a different project (for example the
5388 MTD subsystem) are generally exempt from these guidelines and are not
5389 reformated to ease subsequent migration to newer versions of those
5392 Please note that U-Boot is implemented in C (and to some small parts in
5393 Assembler); no C++ is used, so please do not use C++ style comments (//)
5396 Please also stick to the following formatting rules:
5397 - remove any trailing white space
5398 - use TAB characters for indentation and vertical alignment, not spaces
5399 - make sure NOT to use DOS '\r\n' line feeds
5400 - do not add more than 2 consecutive empty lines to source files
5401 - do not add trailing empty lines to source files
5403 Submissions which do not conform to the standards may be returned
5404 with a request to reformat the changes.
5410 Since the number of patches for U-Boot is growing, we need to
5411 establish some rules. Submissions which do not conform to these rules
5412 may be rejected, even when they contain important and valuable stuff.
5414 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5416 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5417 see http://lists.denx.de/mailman/listinfo/u-boot
5419 When you send a patch, please include the following information with
5422 * For bug fixes: a description of the bug and how your patch fixes
5423 this bug. Please try to include a way of demonstrating that the
5424 patch actually fixes something.
5426 * For new features: a description of the feature and your
5429 * A CHANGELOG entry as plaintext (separate from the patch)
5431 * For major contributions, your entry to the CREDITS file
5433 * When you add support for a new board, don't forget to add this
5434 board to the MAINTAINERS file, too.
5436 * If your patch adds new configuration options, don't forget to
5437 document these in the README file.
5439 * The patch itself. If you are using git (which is *strongly*
5440 recommended) you can easily generate the patch using the
5441 "git format-patch". If you then use "git send-email" to send it to
5442 the U-Boot mailing list, you will avoid most of the common problems
5443 with some other mail clients.
5445 If you cannot use git, use "diff -purN OLD NEW". If your version of
5446 diff does not support these options, then get the latest version of
5449 The current directory when running this command shall be the parent
5450 directory of the U-Boot source tree (i. e. please make sure that
5451 your patch includes sufficient directory information for the
5454 We prefer patches as plain text. MIME attachments are discouraged,
5455 and compressed attachments must not be used.
5457 * If one logical set of modifications affects or creates several
5458 files, all these changes shall be submitted in a SINGLE patch file.
5460 * Changesets that contain different, unrelated modifications shall be
5461 submitted as SEPARATE patches, one patch per changeset.
5466 * Before sending the patch, run the MAKEALL script on your patched
5467 source tree and make sure that no errors or warnings are reported
5468 for any of the boards.
5470 * Keep your modifications to the necessary minimum: A patch
5471 containing several unrelated changes or arbitrary reformats will be
5472 returned with a request to re-formatting / split it.
5474 * If you modify existing code, make sure that your new code does not
5475 add to the memory footprint of the code ;-) Small is beautiful!
5476 When adding new features, these should compile conditionally only
5477 (using #ifdef), and the resulting code with the new feature
5478 disabled must not need more memory than the old code without your
5481 * Remember that there is a size limit of 100 kB per message on the
5482 u-boot mailing list. Bigger patches will be moderated. If they are
5483 reasonable and not too big, they will be acknowledged. But patches
5484 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob