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 - Linux Kernel Interface:
491 U-Boot stores all clock information in Hz
492 internally. For binary compatibility with older Linux
493 kernels (which expect the clocks passed in the
494 bd_info data to be in MHz) the environment variable
495 "clocks_in_mhz" can be defined so that U-Boot
496 converts clock data to MHZ before passing it to the
498 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
499 "clocks_in_mhz=1" is automatically included in the
502 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
504 When transferring memsize parameter to linux, some versions
505 expect it to be in bytes, others in MB.
506 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
510 New kernel versions are expecting firmware settings to be
511 passed using flattened device trees (based on open firmware
515 * New libfdt-based support
516 * Adds the "fdt" command
517 * The bootm command automatically updates the fdt
519 OF_CPU - The proper name of the cpus node (only required for
520 MPC512X and MPC5xxx based boards).
521 OF_SOC - The proper name of the soc node (only required for
522 MPC512X and MPC5xxx based boards).
523 OF_TBCLK - The timebase frequency.
524 OF_STDOUT_PATH - The path to the console device
526 boards with QUICC Engines require OF_QE to set UCC MAC
529 CONFIG_OF_BOARD_SETUP
531 Board code has addition modification that it wants to make
532 to the flat device tree before handing it off to the kernel
536 This define fills in the correct boot CPU in the boot
537 param header, the default value is zero if undefined.
541 U-Boot can detect if an IDE device is present or not.
542 If not, and this new config option is activated, U-Boot
543 removes the ATA node from the DTS before booting Linux,
544 so the Linux IDE driver does not probe the device and
545 crash. This is needed for buggy hardware (uc101) where
546 no pull down resistor is connected to the signal IDE5V_DD7.
548 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
550 This setting is mandatory for all boards that have only one
551 machine type and must be used to specify the machine type
552 number as it appears in the ARM machine registry
553 (see http://www.arm.linux.org.uk/developer/machines/).
554 Only boards that have multiple machine types supported
555 in a single configuration file and the machine type is
556 runtime discoverable, do not have to use this setting.
558 - vxWorks boot parameters:
560 bootvx constructs a valid bootline using the following
561 environments variables: bootfile, ipaddr, serverip, hostname.
562 It loads the vxWorks image pointed bootfile.
564 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
565 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
566 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
567 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
569 CONFIG_SYS_VXWORKS_ADD_PARAMS
571 Add it at the end of the bootline. E.g "u=username pw=secret"
573 Note: If a "bootargs" environment is defined, it will overwride
574 the defaults discussed just above.
576 - Cache Configuration:
577 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
578 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
579 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
581 - Cache Configuration for ARM:
582 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
584 CONFIG_SYS_PL310_BASE - Physical base address of PL310
585 controller register space
590 Define this if you want support for Amba PrimeCell PL010 UARTs.
594 Define this if you want support for Amba PrimeCell PL011 UARTs.
598 If you have Amba PrimeCell PL011 UARTs, set this variable to
599 the clock speed of the UARTs.
603 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
604 define this to a list of base addresses for each (supported)
605 port. See e.g. include/configs/versatile.h
607 CONFIG_PL011_SERIAL_RLCR
609 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
610 have separate receive and transmit line control registers. Set
611 this variable to initialize the extra register.
613 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
615 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
616 boot loader that has already initialized the UART. Define this
617 variable to flush the UART at init time.
619 CONFIG_SYS_NS16550_BROKEN_TEMT
621 16550 UART set the Transmitter Empty (TEMT) Bit when all output
622 has finished and the transmitter is totally empty. U-Boot waits
623 for this bit to be set to initialize the serial console. On some
624 broken platforms this bit is not set in SPL making U-Boot to
625 hang while waiting for TEMT. Define this option to avoid it.
629 Depending on board, define exactly one serial port
630 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
631 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
632 console by defining CONFIG_8xx_CONS_NONE
634 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
635 port routines must be defined elsewhere
636 (i.e. serial_init(), serial_getc(), ...)
639 Enables console device for a color framebuffer. Needs following
640 defines (cf. smiLynxEM, i8042)
641 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
643 VIDEO_HW_RECTFILL graphic chip supports
646 VIDEO_HW_BITBLT graphic chip supports
647 bit-blit (cf. smiLynxEM)
648 VIDEO_VISIBLE_COLS visible pixel columns
650 VIDEO_VISIBLE_ROWS visible pixel rows
651 VIDEO_PIXEL_SIZE bytes per pixel
652 VIDEO_DATA_FORMAT graphic data format
653 (0-5, cf. cfb_console.c)
654 VIDEO_FB_ADRS framebuffer address
655 VIDEO_KBD_INIT_FCT keyboard int fct
656 (i.e. i8042_kbd_init())
657 VIDEO_TSTC_FCT test char fct
659 VIDEO_GETC_FCT get char fct
661 CONFIG_CONSOLE_CURSOR cursor drawing on/off
662 (requires blink timer
664 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
665 CONFIG_CONSOLE_TIME display time/date info in
667 (requires CONFIG_CMD_DATE)
668 CONFIG_VIDEO_LOGO display Linux logo in
670 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
671 linux_logo.h for logo.
672 Requires CONFIG_VIDEO_LOGO
673 CONFIG_CONSOLE_EXTRA_INFO
674 additional board info beside
677 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
678 a limited number of ANSI escape sequences (cursor control,
679 erase functions and limited graphics rendition control).
681 When CONFIG_CFB_CONSOLE is defined, video console is
682 default i/o. Serial console can be forced with
683 environment 'console=serial'.
685 When CONFIG_SILENT_CONSOLE is defined, all console
686 messages (by U-Boot and Linux!) can be silenced with
687 the "silent" environment variable. See
688 doc/README.silent for more information.
691 CONFIG_BAUDRATE - in bps
692 Select one of the baudrates listed in
693 CONFIG_SYS_BAUDRATE_TABLE, see below.
694 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
696 - Console Rx buffer length
697 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
698 the maximum receive buffer length for the SMC.
699 This option is actual only for 82xx and 8xx possible.
700 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
701 must be defined, to setup the maximum idle timeout for
704 - Pre-Console Buffer:
705 Prior to the console being initialised (i.e. serial UART
706 initialised etc) all console output is silently discarded.
707 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
708 buffer any console messages prior to the console being
709 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
710 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
711 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
712 bytes are output before the console is initialised, the
713 earlier bytes are discarded.
715 'Sane' compilers will generate smaller code if
716 CONFIG_PRE_CON_BUF_SZ is a power of 2
718 - Safe printf() functions
719 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
720 the printf() functions. These are defined in
721 include/vsprintf.h and include snprintf(), vsnprintf() and
722 so on. Code size increase is approximately 300-500 bytes.
723 If this option is not given then these functions will
724 silently discard their buffer size argument - this means
725 you are not getting any overflow checking in this case.
727 - Boot Delay: CONFIG_BOOTDELAY - in seconds
728 Delay before automatically booting the default image;
729 set to -1 to disable autoboot.
730 set to -2 to autoboot with no delay and not check for abort
731 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
733 See doc/README.autoboot for these options that
734 work with CONFIG_BOOTDELAY. None are required.
735 CONFIG_BOOT_RETRY_TIME
736 CONFIG_BOOT_RETRY_MIN
737 CONFIG_AUTOBOOT_KEYED
738 CONFIG_AUTOBOOT_PROMPT
739 CONFIG_AUTOBOOT_DELAY_STR
740 CONFIG_AUTOBOOT_STOP_STR
741 CONFIG_AUTOBOOT_DELAY_STR2
742 CONFIG_AUTOBOOT_STOP_STR2
743 CONFIG_ZERO_BOOTDELAY_CHECK
744 CONFIG_RESET_TO_RETRY
748 Only needed when CONFIG_BOOTDELAY is enabled;
749 define a command string that is automatically executed
750 when no character is read on the console interface
751 within "Boot Delay" after reset.
754 This can be used to pass arguments to the bootm
755 command. The value of CONFIG_BOOTARGS goes into the
756 environment value "bootargs".
758 CONFIG_RAMBOOT and CONFIG_NFSBOOT
759 The value of these goes into the environment as
760 "ramboot" and "nfsboot" respectively, and can be used
761 as a convenience, when switching between booting from
767 When this option is #defined, the existence of the
768 environment variable "preboot" will be checked
769 immediately before starting the CONFIG_BOOTDELAY
770 countdown and/or running the auto-boot command resp.
771 entering interactive mode.
773 This feature is especially useful when "preboot" is
774 automatically generated or modified. For an example
775 see the LWMON board specific code: here "preboot" is
776 modified when the user holds down a certain
777 combination of keys on the (special) keyboard when
780 - Serial Download Echo Mode:
782 If defined to 1, all characters received during a
783 serial download (using the "loads" command) are
784 echoed back. This might be needed by some terminal
785 emulations (like "cu"), but may as well just take
786 time on others. This setting #define's the initial
787 value of the "loads_echo" environment variable.
789 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
791 Select one of the baudrates listed in
792 CONFIG_SYS_BAUDRATE_TABLE, see below.
795 Monitor commands can be included or excluded
796 from the build by using the #include files
797 <config_cmd_all.h> and #undef'ing unwanted
798 commands, or using <config_cmd_default.h>
799 and augmenting with additional #define's
802 The default command configuration includes all commands
803 except those marked below with a "*".
805 CONFIG_CMD_ASKENV * ask for env variable
806 CONFIG_CMD_BDI bdinfo
807 CONFIG_CMD_BEDBUG * Include BedBug Debugger
808 CONFIG_CMD_BMP * BMP support
809 CONFIG_CMD_BSP * Board specific commands
810 CONFIG_CMD_BOOTD bootd
811 CONFIG_CMD_CACHE * icache, dcache
812 CONFIG_CMD_CONSOLE coninfo
813 CONFIG_CMD_CRC32 * crc32
814 CONFIG_CMD_DATE * support for RTC, date/time...
815 CONFIG_CMD_DHCP * DHCP support
816 CONFIG_CMD_DIAG * Diagnostics
817 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
818 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
819 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
820 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
821 CONFIG_CMD_DTT * Digital Therm and Thermostat
822 CONFIG_CMD_ECHO echo arguments
823 CONFIG_CMD_EDITENV edit env variable
824 CONFIG_CMD_EEPROM * EEPROM read/write support
825 CONFIG_CMD_ELF * bootelf, bootvx
826 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
827 CONFIG_CMD_ENV_FLAGS * display details about env flags
828 CONFIG_CMD_EXPORTENV * export the environment
829 CONFIG_CMD_EXT2 * ext2 command support
830 CONFIG_CMD_EXT4 * ext4 command support
831 CONFIG_CMD_SAVEENV saveenv
832 CONFIG_CMD_FDC * Floppy Disk Support
833 CONFIG_CMD_FAT * FAT command support
834 CONFIG_CMD_FDOS * Dos diskette Support
835 CONFIG_CMD_FLASH flinfo, erase, protect
836 CONFIG_CMD_FPGA FPGA device initialization support
837 CONFIG_CMD_GETTIME * Get time since boot
838 CONFIG_CMD_GO * the 'go' command (exec code)
839 CONFIG_CMD_GREPENV * search environment
840 CONFIG_CMD_HASH * calculate hash / digest
841 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
842 CONFIG_CMD_I2C * I2C serial bus support
843 CONFIG_CMD_IDE * IDE harddisk support
844 CONFIG_CMD_IMI iminfo
845 CONFIG_CMD_IMLS List all found images
846 CONFIG_CMD_IMMAP * IMMR dump support
847 CONFIG_CMD_IMPORTENV * import an environment
848 CONFIG_CMD_INI * import data from an ini file into the env
849 CONFIG_CMD_IRQ * irqinfo
850 CONFIG_CMD_ITEST Integer/string test of 2 values
851 CONFIG_CMD_JFFS2 * JFFS2 Support
852 CONFIG_CMD_KGDB * kgdb
853 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
854 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
856 CONFIG_CMD_LOADB loadb
857 CONFIG_CMD_LOADS loads
858 CONFIG_CMD_MD5SUM print md5 message digest
859 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
860 CONFIG_CMD_MEMINFO * Display detailed memory information
861 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
863 CONFIG_CMD_MISC Misc functions like sleep etc
864 CONFIG_CMD_MMC * MMC memory mapped support
865 CONFIG_CMD_MII * MII utility commands
866 CONFIG_CMD_MTDPARTS * MTD partition support
867 CONFIG_CMD_NAND * NAND support
868 CONFIG_CMD_NET bootp, tftpboot, rarpboot
869 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
870 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
871 CONFIG_CMD_PCI * pciinfo
872 CONFIG_CMD_PCMCIA * PCMCIA support
873 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
875 CONFIG_CMD_PORTIO * Port I/O
876 CONFIG_CMD_READ * Read raw data from partition
877 CONFIG_CMD_REGINFO * Register dump
878 CONFIG_CMD_RUN run command in env variable
879 CONFIG_CMD_SAVES * save S record dump
880 CONFIG_CMD_SCSI * SCSI Support
881 CONFIG_CMD_SDRAM * print SDRAM configuration information
882 (requires CONFIG_CMD_I2C)
883 CONFIG_CMD_SETGETDCR Support for DCR Register access
885 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
886 CONFIG_CMD_SHA1SUM print sha1 memory digest
887 (requires CONFIG_CMD_MEMORY)
888 CONFIG_CMD_SOURCE "source" command Support
889 CONFIG_CMD_SPI * SPI serial bus support
890 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
891 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
892 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
893 CONFIG_CMD_TIMER * access to the system tick timer
894 CONFIG_CMD_USB * USB support
895 CONFIG_CMD_CDP * Cisco Discover Protocol support
896 CONFIG_CMD_MFSL * Microblaze FSL support
899 EXAMPLE: If you want all functions except of network
900 support you can write:
902 #include "config_cmd_all.h"
903 #undef CONFIG_CMD_NET
906 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
908 Note: Don't enable the "icache" and "dcache" commands
909 (configuration option CONFIG_CMD_CACHE) unless you know
910 what you (and your U-Boot users) are doing. Data
911 cache cannot be enabled on systems like the 8xx or
912 8260 (where accesses to the IMMR region must be
913 uncached), and it cannot be disabled on all other
914 systems where we (mis-) use the data cache to hold an
915 initial stack and some data.
918 XXX - this list needs to get updated!
922 If this variable is defined, U-Boot will use a device tree
923 to configure its devices, instead of relying on statically
924 compiled #defines in the board file. This option is
925 experimental and only available on a few boards. The device
926 tree is available in the global data as gd->fdt_blob.
928 U-Boot needs to get its device tree from somewhere. This can
929 be done using one of the two options below:
932 If this variable is defined, U-Boot will embed a device tree
933 binary in its image. This device tree file should be in the
934 board directory and called <soc>-<board>.dts. The binary file
935 is then picked up in board_init_f() and made available through
936 the global data structure as gd->blob.
939 If this variable is defined, U-Boot will build a device tree
940 binary. It will be called u-boot.dtb. Architecture-specific
941 code will locate it at run-time. Generally this works by:
943 cat u-boot.bin u-boot.dtb >image.bin
945 and in fact, U-Boot does this for you, creating a file called
946 u-boot-dtb.bin which is useful in the common case. You can
947 still use the individual files if you need something more
952 If this variable is defined, it enables watchdog
953 support for the SoC. There must be support in the SoC
954 specific code for a watchdog. For the 8xx and 8260
955 CPUs, the SIU Watchdog feature is enabled in the SYPCR
956 register. When supported for a specific SoC is
957 available, then no further board specific code should
961 When using a watchdog circuitry external to the used
962 SoC, then define this variable and provide board
963 specific code for the "hw_watchdog_reset" function.
966 CONFIG_VERSION_VARIABLE
967 If this variable is defined, an environment variable
968 named "ver" is created by U-Boot showing the U-Boot
969 version as printed by the "version" command.
970 Any change to this variable will be reverted at the
975 When CONFIG_CMD_DATE is selected, the type of the RTC
976 has to be selected, too. Define exactly one of the
979 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
980 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
981 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
982 CONFIG_RTC_MC146818 - use MC146818 RTC
983 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
984 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
985 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
986 CONFIG_RTC_DS164x - use Dallas DS164x RTC
987 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
988 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
989 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
990 CONFIG_SYS_RV3029_TCR - enable trickle charger on
993 Note that if the RTC uses I2C, then the I2C interface
994 must also be configured. See I2C Support, below.
997 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
998 CONFIG_PCA953X_INFO - enable pca953x info command
1000 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1001 chip-ngpio pairs that tell the PCA953X driver the number of
1002 pins supported by a particular chip.
1004 Note that if the GPIO device uses I2C, then the I2C interface
1005 must also be configured. See I2C Support, below.
1007 - Timestamp Support:
1009 When CONFIG_TIMESTAMP is selected, the timestamp
1010 (date and time) of an image is printed by image
1011 commands like bootm or iminfo. This option is
1012 automatically enabled when you select CONFIG_CMD_DATE .
1014 - Partition Labels (disklabels) Supported:
1015 Zero or more of the following:
1016 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1017 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1018 Intel architecture, USB sticks, etc.
1019 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1020 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1021 bootloader. Note 2TB partition limit; see
1023 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1025 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1026 CONFIG_CMD_SCSI) you must configure support for at
1027 least one non-MTD partition type as well.
1030 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1031 board configurations files but used nowhere!
1033 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1034 be performed by calling the function
1035 ide_set_reset(int reset)
1036 which has to be defined in a board specific file
1041 Set this to enable ATAPI support.
1046 Set this to enable support for disks larger than 137GB
1047 Also look at CONFIG_SYS_64BIT_LBA.
1048 Whithout these , LBA48 support uses 32bit variables and will 'only'
1049 support disks up to 2.1TB.
1051 CONFIG_SYS_64BIT_LBA:
1052 When enabled, makes the IDE subsystem use 64bit sector addresses.
1056 At the moment only there is only support for the
1057 SYM53C8XX SCSI controller; define
1058 CONFIG_SCSI_SYM53C8XX to enable it.
1060 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1061 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1062 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1063 maximum numbers of LUNs, SCSI ID's and target
1065 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1067 The environment variable 'scsidevs' is set to the number of
1068 SCSI devices found during the last scan.
1070 - NETWORK Support (PCI):
1072 Support for Intel 8254x/8257x gigabit chips.
1075 Utility code for direct access to the SPI bus on Intel 8257x.
1076 This does not do anything useful unless you set at least one
1077 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1079 CONFIG_E1000_SPI_GENERIC
1080 Allow generic access to the SPI bus on the Intel 8257x, for
1081 example with the "sspi" command.
1084 Management command for E1000 devices. When used on devices
1085 with SPI support you can reprogram the EEPROM from U-Boot.
1087 CONFIG_E1000_FALLBACK_MAC
1088 default MAC for empty EEPROM after production.
1091 Support for Intel 82557/82559/82559ER chips.
1092 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1093 write routine for first time initialisation.
1096 Support for Digital 2114x chips.
1097 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1098 modem chip initialisation (KS8761/QS6611).
1101 Support for National dp83815 chips.
1104 Support for National dp8382[01] gigabit chips.
1106 - NETWORK Support (other):
1108 CONFIG_DRIVER_AT91EMAC
1109 Support for AT91RM9200 EMAC.
1112 Define this to use reduced MII inteface
1114 CONFIG_DRIVER_AT91EMAC_QUIET
1115 If this defined, the driver is quiet.
1116 The driver doen't show link status messages.
1118 CONFIG_CALXEDA_XGMAC
1119 Support for the Calxeda XGMAC device
1122 Support for SMSC's LAN91C96 chips.
1124 CONFIG_LAN91C96_BASE
1125 Define this to hold the physical address
1126 of the LAN91C96's I/O space
1128 CONFIG_LAN91C96_USE_32_BIT
1129 Define this to enable 32 bit addressing
1132 Support for SMSC's LAN91C111 chip
1134 CONFIG_SMC91111_BASE
1135 Define this to hold the physical address
1136 of the device (I/O space)
1138 CONFIG_SMC_USE_32_BIT
1139 Define this if data bus is 32 bits
1141 CONFIG_SMC_USE_IOFUNCS
1142 Define this to use i/o functions instead of macros
1143 (some hardware wont work with macros)
1145 CONFIG_DRIVER_TI_EMAC
1146 Support for davinci emac
1148 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1149 Define this if you have more then 3 PHYs.
1152 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1154 CONFIG_FTGMAC100_EGIGA
1155 Define this to use GE link update with gigabit PHY.
1156 Define this if FTGMAC100 is connected to gigabit PHY.
1157 If your system has 10/100 PHY only, it might not occur
1158 wrong behavior. Because PHY usually return timeout or
1159 useless data when polling gigabit status and gigabit
1160 control registers. This behavior won't affect the
1161 correctnessof 10/100 link speed update.
1164 Support for SMSC's LAN911x and LAN921x chips
1167 Define this to hold the physical address
1168 of the device (I/O space)
1170 CONFIG_SMC911X_32_BIT
1171 Define this if data bus is 32 bits
1173 CONFIG_SMC911X_16_BIT
1174 Define this if data bus is 16 bits. If your processor
1175 automatically converts one 32 bit word to two 16 bit
1176 words you may also try CONFIG_SMC911X_32_BIT.
1179 Support for Renesas on-chip Ethernet controller
1181 CONFIG_SH_ETHER_USE_PORT
1182 Define the number of ports to be used
1184 CONFIG_SH_ETHER_PHY_ADDR
1185 Define the ETH PHY's address
1187 CONFIG_SH_ETHER_CACHE_WRITEBACK
1188 If this option is set, the driver enables cache flush.
1191 CONFIG_GENERIC_LPC_TPM
1192 Support for generic parallel port TPM devices. Only one device
1193 per system is supported at this time.
1195 CONFIG_TPM_TIS_BASE_ADDRESS
1196 Base address where the generic TPM device is mapped
1197 to. Contemporary x86 systems usually map it at
1201 At the moment only the UHCI host controller is
1202 supported (PIP405, MIP405, MPC5200); define
1203 CONFIG_USB_UHCI to enable it.
1204 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1205 and define CONFIG_USB_STORAGE to enable the USB
1208 Supported are USB Keyboards and USB Floppy drives
1210 MPC5200 USB requires additional defines:
1212 for 528 MHz Clock: 0x0001bbbb
1216 for differential drivers: 0x00001000
1217 for single ended drivers: 0x00005000
1218 for differential drivers on PSC3: 0x00000100
1219 for single ended drivers on PSC3: 0x00004100
1220 CONFIG_SYS_USB_EVENT_POLL
1221 May be defined to allow interrupt polling
1222 instead of using asynchronous interrupts
1224 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1225 txfilltuning field in the EHCI controller on reset.
1228 Define the below if you wish to use the USB console.
1229 Once firmware is rebuilt from a serial console issue the
1230 command "setenv stdin usbtty; setenv stdout usbtty" and
1231 attach your USB cable. The Unix command "dmesg" should print
1232 it has found a new device. The environment variable usbtty
1233 can be set to gserial or cdc_acm to enable your device to
1234 appear to a USB host as a Linux gserial device or a
1235 Common Device Class Abstract Control Model serial device.
1236 If you select usbtty = gserial you should be able to enumerate
1238 # modprobe usbserial vendor=0xVendorID product=0xProductID
1239 else if using cdc_acm, simply setting the environment
1240 variable usbtty to be cdc_acm should suffice. The following
1241 might be defined in YourBoardName.h
1244 Define this to build a UDC device
1247 Define this to have a tty type of device available to
1248 talk to the UDC device
1251 Define this to enable the high speed support for usb
1252 device and usbtty. If this feature is enabled, a routine
1253 int is_usbd_high_speed(void)
1254 also needs to be defined by the driver to dynamically poll
1255 whether the enumeration has succeded at high speed or full
1258 CONFIG_SYS_CONSOLE_IS_IN_ENV
1259 Define this if you want stdin, stdout &/or stderr to
1263 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1264 Derive USB clock from external clock "blah"
1265 - CONFIG_SYS_USB_EXTC_CLK 0x02
1267 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1268 Derive USB clock from brgclk
1269 - CONFIG_SYS_USB_BRG_CLK 0x04
1271 If you have a USB-IF assigned VendorID then you may wish to
1272 define your own vendor specific values either in BoardName.h
1273 or directly in usbd_vendor_info.h. If you don't define
1274 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1275 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1276 should pretend to be a Linux device to it's target host.
1278 CONFIG_USBD_MANUFACTURER
1279 Define this string as the name of your company for
1280 - CONFIG_USBD_MANUFACTURER "my company"
1282 CONFIG_USBD_PRODUCT_NAME
1283 Define this string as the name of your product
1284 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1286 CONFIG_USBD_VENDORID
1287 Define this as your assigned Vendor ID from the USB
1288 Implementors Forum. This *must* be a genuine Vendor ID
1289 to avoid polluting the USB namespace.
1290 - CONFIG_USBD_VENDORID 0xFFFF
1292 CONFIG_USBD_PRODUCTID
1293 Define this as the unique Product ID
1295 - CONFIG_USBD_PRODUCTID 0xFFFF
1297 - ULPI Layer Support:
1298 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1299 the generic ULPI layer. The generic layer accesses the ULPI PHY
1300 via the platform viewport, so you need both the genric layer and
1301 the viewport enabled. Currently only Chipidea/ARC based
1302 viewport is supported.
1303 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1304 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1305 If your ULPI phy needs a different reference clock than the
1306 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1307 the appropriate value in Hz.
1310 The MMC controller on the Intel PXA is supported. To
1311 enable this define CONFIG_MMC. The MMC can be
1312 accessed from the boot prompt by mapping the device
1313 to physical memory similar to flash. Command line is
1314 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1315 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1318 Support for Renesas on-chip MMCIF controller
1320 CONFIG_SH_MMCIF_ADDR
1321 Define the base address of MMCIF registers
1324 Define the clock frequency for MMCIF
1326 - Journaling Flash filesystem support:
1327 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1328 CONFIG_JFFS2_NAND_DEV
1329 Define these for a default partition on a NAND device
1331 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1332 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1333 Define these for a default partition on a NOR device
1335 CONFIG_SYS_JFFS_CUSTOM_PART
1336 Define this to create an own partition. You have to provide a
1337 function struct part_info* jffs2_part_info(int part_num)
1339 If you define only one JFFS2 partition you may also want to
1340 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1341 to disable the command chpart. This is the default when you
1342 have not defined a custom partition
1344 - FAT(File Allocation Table) filesystem write function support:
1347 Define this to enable support for saving memory data as a
1348 file in FAT formatted partition.
1350 This will also enable the command "fatwrite" enabling the
1351 user to write files to FAT.
1353 CBFS (Coreboot Filesystem) support
1356 Define this to enable support for reading from a Coreboot
1357 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1363 Define this to enable standard (PC-Style) keyboard
1367 Standard PC keyboard driver with US (is default) and
1368 GERMAN key layout (switch via environment 'keymap=de') support.
1369 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1370 for cfb_console. Supports cursor blinking.
1375 Define this to enable video support (for output to
1378 CONFIG_VIDEO_CT69000
1380 Enable Chips & Technologies 69000 Video chip
1382 CONFIG_VIDEO_SMI_LYNXEM
1383 Enable Silicon Motion SMI 712/710/810 Video chip. The
1384 video output is selected via environment 'videoout'
1385 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1388 For the CT69000 and SMI_LYNXEM drivers, videomode is
1389 selected via environment 'videomode'. Two different ways
1391 - "videomode=num" 'num' is a standard LiLo mode numbers.
1392 Following standard modes are supported (* is default):
1394 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1395 -------------+---------------------------------------------
1396 8 bits | 0x301* 0x303 0x305 0x161 0x307
1397 15 bits | 0x310 0x313 0x316 0x162 0x319
1398 16 bits | 0x311 0x314 0x317 0x163 0x31A
1399 24 bits | 0x312 0x315 0x318 ? 0x31B
1400 -------------+---------------------------------------------
1401 (i.e. setenv videomode 317; saveenv; reset;)
1403 - "videomode=bootargs" all the video parameters are parsed
1404 from the bootargs. (See drivers/video/videomodes.c)
1407 CONFIG_VIDEO_SED13806
1408 Enable Epson SED13806 driver. This driver supports 8bpp
1409 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1410 or CONFIG_VIDEO_SED13806_16BPP
1413 Enable the Freescale DIU video driver. Reference boards for
1414 SOCs that have a DIU should define this macro to enable DIU
1415 support, and should also define these other macros:
1421 CONFIG_VIDEO_SW_CURSOR
1422 CONFIG_VGA_AS_SINGLE_DEVICE
1424 CONFIG_VIDEO_BMP_LOGO
1426 The DIU driver will look for the 'video-mode' environment
1427 variable, and if defined, enable the DIU as a console during
1428 boot. See the documentation file README.video for a
1429 description of this variable.
1433 Enable the VGA video / BIOS for x86. The alternative if you
1434 are using coreboot is to use the coreboot frame buffer
1441 Define this to enable a custom keyboard support.
1442 This simply calls drv_keyboard_init() which must be
1443 defined in your board-specific files.
1444 The only board using this so far is RBC823.
1446 - LCD Support: CONFIG_LCD
1448 Define this to enable LCD support (for output to LCD
1449 display); also select one of the supported displays
1450 by defining one of these:
1454 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1456 CONFIG_NEC_NL6448AC33:
1458 NEC NL6448AC33-18. Active, color, single scan.
1460 CONFIG_NEC_NL6448BC20
1462 NEC NL6448BC20-08. 6.5", 640x480.
1463 Active, color, single scan.
1465 CONFIG_NEC_NL6448BC33_54
1467 NEC NL6448BC33-54. 10.4", 640x480.
1468 Active, color, single scan.
1472 Sharp 320x240. Active, color, single scan.
1473 It isn't 16x9, and I am not sure what it is.
1475 CONFIG_SHARP_LQ64D341
1477 Sharp LQ64D341 display, 640x480.
1478 Active, color, single scan.
1482 HLD1045 display, 640x480.
1483 Active, color, single scan.
1487 Optrex CBL50840-2 NF-FW 99 22 M5
1489 Hitachi LMG6912RPFC-00T
1493 320x240. Black & white.
1495 Normally display is black on white background; define
1496 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1498 CONFIG_LCD_ALIGNMENT
1500 Normally the LCD is page-aligned (tyically 4KB). If this is
1501 defined then the LCD will be aligned to this value instead.
1502 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1503 here, since it is cheaper to change data cache settings on
1504 a per-section basis.
1506 CONFIG_CONSOLE_SCROLL_LINES
1508 When the console need to be scrolled, this is the number of
1509 lines to scroll by. It defaults to 1. Increasing this makes
1510 the console jump but can help speed up operation when scrolling
1515 Support drawing of RLE8-compressed bitmaps on the LCD.
1519 Enables an 'i2c edid' command which can read EDID
1520 information over I2C from an attached LCD display.
1522 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1524 If this option is set, the environment is checked for
1525 a variable "splashimage". If found, the usual display
1526 of logo, copyright and system information on the LCD
1527 is suppressed and the BMP image at the address
1528 specified in "splashimage" is loaded instead. The
1529 console is redirected to the "nulldev", too. This
1530 allows for a "silent" boot where a splash screen is
1531 loaded very quickly after power-on.
1533 CONFIG_SPLASHIMAGE_GUARD
1535 If this option is set, then U-Boot will prevent the environment
1536 variable "splashimage" from being set to a problematic address
1537 (see README.displaying-bmps and README.arm-unaligned-accesses).
1538 This option is useful for targets where, due to alignment
1539 restrictions, an improperly aligned BMP image will cause a data
1540 abort. If you think you will not have problems with unaligned
1541 accesses (for example because your toolchain prevents them)
1542 there is no need to set this option.
1544 CONFIG_SPLASH_SCREEN_ALIGN
1546 If this option is set the splash image can be freely positioned
1547 on the screen. Environment variable "splashpos" specifies the
1548 position as "x,y". If a positive number is given it is used as
1549 number of pixel from left/top. If a negative number is given it
1550 is used as number of pixel from right/bottom. You can also
1551 specify 'm' for centering the image.
1554 setenv splashpos m,m
1555 => image at center of screen
1557 setenv splashpos 30,20
1558 => image at x = 30 and y = 20
1560 setenv splashpos -10,m
1561 => vertically centered image
1562 at x = dspWidth - bmpWidth - 9
1564 CONFIG_SPLASH_SCREEN_PREPARE
1566 If this option is set then the board_splash_screen_prepare()
1567 function, which must be defined in your code, is called as part
1568 of the splash screen display sequence. It gives the board an
1569 opportunity to prepare the splash image data before it is
1570 processed and sent to the frame buffer by U-Boot.
1572 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1574 If this option is set, additionally to standard BMP
1575 images, gzipped BMP images can be displayed via the
1576 splashscreen support or the bmp command.
1578 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1580 If this option is set, 8-bit RLE compressed BMP images
1581 can be displayed via the splashscreen support or the
1584 - Do compresssing for memory range:
1587 If this option is set, it would use zlib deflate method
1588 to compress the specified memory at its best effort.
1590 - Compression support:
1593 If this option is set, support for bzip2 compressed
1594 images is included. If not, only uncompressed and gzip
1595 compressed images are supported.
1597 NOTE: the bzip2 algorithm requires a lot of RAM, so
1598 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1603 If this option is set, support for lzma compressed
1606 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1607 requires an amount of dynamic memory that is given by the
1610 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1612 Where lc and lp stand for, respectively, Literal context bits
1613 and Literal pos bits.
1615 This value is upper-bounded by 14MB in the worst case. Anyway,
1616 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1617 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1618 a very small buffer.
1620 Use the lzmainfo tool to determinate the lc and lp values and
1621 then calculate the amount of needed dynamic memory (ensuring
1622 the appropriate CONFIG_SYS_MALLOC_LEN value).
1627 The address of PHY on MII bus.
1629 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1631 The clock frequency of the MII bus
1635 If this option is set, support for speed/duplex
1636 detection of gigabit PHY is included.
1638 CONFIG_PHY_RESET_DELAY
1640 Some PHY like Intel LXT971A need extra delay after
1641 reset before any MII register access is possible.
1642 For such PHY, set this option to the usec delay
1643 required. (minimum 300usec for LXT971A)
1645 CONFIG_PHY_CMD_DELAY (ppc4xx)
1647 Some PHY like Intel LXT971A need extra delay after
1648 command issued before MII status register can be read
1658 Define a default value for Ethernet address to use
1659 for the respective Ethernet interface, in case this
1660 is not determined automatically.
1665 Define a default value for the IP address to use for
1666 the default Ethernet interface, in case this is not
1667 determined through e.g. bootp.
1668 (Environment variable "ipaddr")
1670 - Server IP address:
1673 Defines a default value for the IP address of a TFTP
1674 server to contact when using the "tftboot" command.
1675 (Environment variable "serverip")
1677 CONFIG_KEEP_SERVERADDR
1679 Keeps the server's MAC address, in the env 'serveraddr'
1680 for passing to bootargs (like Linux's netconsole option)
1682 - Gateway IP address:
1685 Defines a default value for the IP address of the
1686 default router where packets to other networks are
1688 (Environment variable "gatewayip")
1693 Defines a default value for the subnet mask (or
1694 routing prefix) which is used to determine if an IP
1695 address belongs to the local subnet or needs to be
1696 forwarded through a router.
1697 (Environment variable "netmask")
1699 - Multicast TFTP Mode:
1702 Defines whether you want to support multicast TFTP as per
1703 rfc-2090; for example to work with atftp. Lets lots of targets
1704 tftp down the same boot image concurrently. Note: the Ethernet
1705 driver in use must provide a function: mcast() to join/leave a
1708 - BOOTP Recovery Mode:
1709 CONFIG_BOOTP_RANDOM_DELAY
1711 If you have many targets in a network that try to
1712 boot using BOOTP, you may want to avoid that all
1713 systems send out BOOTP requests at precisely the same
1714 moment (which would happen for instance at recovery
1715 from a power failure, when all systems will try to
1716 boot, thus flooding the BOOTP server. Defining
1717 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1718 inserted before sending out BOOTP requests. The
1719 following delays are inserted then:
1721 1st BOOTP request: delay 0 ... 1 sec
1722 2nd BOOTP request: delay 0 ... 2 sec
1723 3rd BOOTP request: delay 0 ... 4 sec
1725 BOOTP requests: delay 0 ... 8 sec
1727 - DHCP Advanced Options:
1728 You can fine tune the DHCP functionality by defining
1729 CONFIG_BOOTP_* symbols:
1731 CONFIG_BOOTP_SUBNETMASK
1732 CONFIG_BOOTP_GATEWAY
1733 CONFIG_BOOTP_HOSTNAME
1734 CONFIG_BOOTP_NISDOMAIN
1735 CONFIG_BOOTP_BOOTPATH
1736 CONFIG_BOOTP_BOOTFILESIZE
1739 CONFIG_BOOTP_SEND_HOSTNAME
1740 CONFIG_BOOTP_NTPSERVER
1741 CONFIG_BOOTP_TIMEOFFSET
1742 CONFIG_BOOTP_VENDOREX
1743 CONFIG_BOOTP_MAY_FAIL
1745 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1746 environment variable, not the BOOTP server.
1748 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1749 after the configured retry count, the call will fail
1750 instead of starting over. This can be used to fail over
1751 to Link-local IP address configuration if the DHCP server
1754 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1755 serverip from a DHCP server, it is possible that more
1756 than one DNS serverip is offered to the client.
1757 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1758 serverip will be stored in the additional environment
1759 variable "dnsip2". The first DNS serverip is always
1760 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1763 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1764 to do a dynamic update of a DNS server. To do this, they
1765 need the hostname of the DHCP requester.
1766 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1767 of the "hostname" environment variable is passed as
1768 option 12 to the DHCP server.
1770 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1772 A 32bit value in microseconds for a delay between
1773 receiving a "DHCP Offer" and sending the "DHCP Request".
1774 This fixes a problem with certain DHCP servers that don't
1775 respond 100% of the time to a "DHCP request". E.g. On an
1776 AT91RM9200 processor running at 180MHz, this delay needed
1777 to be *at least* 15,000 usec before a Windows Server 2003
1778 DHCP server would reply 100% of the time. I recommend at
1779 least 50,000 usec to be safe. The alternative is to hope
1780 that one of the retries will be successful but note that
1781 the DHCP timeout and retry process takes a longer than
1784 - Link-local IP address negotiation:
1785 Negotiate with other link-local clients on the local network
1786 for an address that doesn't require explicit configuration.
1787 This is especially useful if a DHCP server cannot be guaranteed
1788 to exist in all environments that the device must operate.
1790 See doc/README.link-local for more information.
1793 CONFIG_CDP_DEVICE_ID
1795 The device id used in CDP trigger frames.
1797 CONFIG_CDP_DEVICE_ID_PREFIX
1799 A two character string which is prefixed to the MAC address
1804 A printf format string which contains the ascii name of
1805 the port. Normally is set to "eth%d" which sets
1806 eth0 for the first Ethernet, eth1 for the second etc.
1808 CONFIG_CDP_CAPABILITIES
1810 A 32bit integer which indicates the device capabilities;
1811 0x00000010 for a normal host which does not forwards.
1815 An ascii string containing the version of the software.
1819 An ascii string containing the name of the platform.
1823 A 32bit integer sent on the trigger.
1825 CONFIG_CDP_POWER_CONSUMPTION
1827 A 16bit integer containing the power consumption of the
1828 device in .1 of milliwatts.
1830 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1832 A byte containing the id of the VLAN.
1834 - Status LED: CONFIG_STATUS_LED
1836 Several configurations allow to display the current
1837 status using a LED. For instance, the LED will blink
1838 fast while running U-Boot code, stop blinking as
1839 soon as a reply to a BOOTP request was received, and
1840 start blinking slow once the Linux kernel is running
1841 (supported by a status LED driver in the Linux
1842 kernel). Defining CONFIG_STATUS_LED enables this
1845 - CAN Support: CONFIG_CAN_DRIVER
1847 Defining CONFIG_CAN_DRIVER enables CAN driver support
1848 on those systems that support this (optional)
1849 feature, like the TQM8xxL modules.
1851 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1853 These enable I2C serial bus commands. Defining either of
1854 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1855 include the appropriate I2C driver for the selected CPU.
1857 This will allow you to use i2c commands at the u-boot
1858 command line (as long as you set CONFIG_CMD_I2C in
1859 CONFIG_COMMANDS) and communicate with i2c based realtime
1860 clock chips. See common/cmd_i2c.c for a description of the
1861 command line interface.
1863 CONFIG_HARD_I2C selects a hardware I2C controller.
1865 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1866 bit-banging) driver instead of CPM or similar hardware
1869 There are several other quantities that must also be
1870 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1872 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1873 to be the frequency (in Hz) at which you wish your i2c bus
1874 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1875 the CPU's i2c node address).
1877 Now, the u-boot i2c code for the mpc8xx
1878 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1879 and so its address should therefore be cleared to 0 (See,
1880 eg, MPC823e User's Manual p.16-473). So, set
1881 CONFIG_SYS_I2C_SLAVE to 0.
1883 CONFIG_SYS_I2C_INIT_MPC5XXX
1885 When a board is reset during an i2c bus transfer
1886 chips might think that the current transfer is still
1887 in progress. Reset the slave devices by sending start
1888 commands until the slave device responds.
1890 That's all that's required for CONFIG_HARD_I2C.
1892 If you use the software i2c interface (CONFIG_SOFT_I2C)
1893 then the following macros need to be defined (examples are
1894 from include/configs/lwmon.h):
1898 (Optional). Any commands necessary to enable the I2C
1899 controller or configure ports.
1901 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1905 (Only for MPC8260 CPU). The I/O port to use (the code
1906 assumes both bits are on the same port). Valid values
1907 are 0..3 for ports A..D.
1911 The code necessary to make the I2C data line active
1912 (driven). If the data line is open collector, this
1915 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1919 The code necessary to make the I2C data line tri-stated
1920 (inactive). If the data line is open collector, this
1923 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1927 Code that returns TRUE if the I2C data line is high,
1930 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1934 If <bit> is TRUE, sets the I2C data line high. If it
1935 is FALSE, it clears it (low).
1937 eg: #define I2C_SDA(bit) \
1938 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1939 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1943 If <bit> is TRUE, sets the I2C clock line high. If it
1944 is FALSE, it clears it (low).
1946 eg: #define I2C_SCL(bit) \
1947 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1948 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1952 This delay is invoked four times per clock cycle so this
1953 controls the rate of data transfer. The data rate thus
1954 is 1 / (I2C_DELAY * 4). Often defined to be something
1957 #define I2C_DELAY udelay(2)
1959 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1961 If your arch supports the generic GPIO framework (asm/gpio.h),
1962 then you may alternatively define the two GPIOs that are to be
1963 used as SCL / SDA. Any of the previous I2C_xxx macros will
1964 have GPIO-based defaults assigned to them as appropriate.
1966 You should define these to the GPIO value as given directly to
1967 the generic GPIO functions.
1969 CONFIG_SYS_I2C_INIT_BOARD
1971 When a board is reset during an i2c bus transfer
1972 chips might think that the current transfer is still
1973 in progress. On some boards it is possible to access
1974 the i2c SCLK line directly, either by using the
1975 processor pin as a GPIO or by having a second pin
1976 connected to the bus. If this option is defined a
1977 custom i2c_init_board() routine in boards/xxx/board.c
1978 is run early in the boot sequence.
1980 CONFIG_SYS_I2C_BOARD_LATE_INIT
1982 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1983 defined a custom i2c_board_late_init() routine in
1984 boards/xxx/board.c is run AFTER the operations in i2c_init()
1985 is completed. This callpoint can be used to unreset i2c bus
1986 using CPU i2c controller register accesses for CPUs whose i2c
1987 controller provide such a method. It is called at the end of
1988 i2c_init() to allow i2c_init operations to setup the i2c bus
1989 controller on the CPU (e.g. setting bus speed & slave address).
1991 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1993 This option enables configuration of bi_iic_fast[] flags
1994 in u-boot bd_info structure based on u-boot environment
1995 variable "i2cfast". (see also i2cfast)
1997 CONFIG_I2C_MULTI_BUS
1999 This option allows the use of multiple I2C buses, each of which
2000 must have a controller. At any point in time, only one bus is
2001 active. To switch to a different bus, use the 'i2c dev' command.
2002 Note that bus numbering is zero-based.
2004 CONFIG_SYS_I2C_NOPROBES
2006 This option specifies a list of I2C devices that will be skipped
2007 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2008 is set, specify a list of bus-device pairs. Otherwise, specify
2009 a 1D array of device addresses
2012 #undef CONFIG_I2C_MULTI_BUS
2013 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2015 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2017 #define CONFIG_I2C_MULTI_BUS
2018 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2020 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2022 CONFIG_SYS_SPD_BUS_NUM
2024 If defined, then this indicates the I2C bus number for DDR SPD.
2025 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2027 CONFIG_SYS_RTC_BUS_NUM
2029 If defined, then this indicates the I2C bus number for the RTC.
2030 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2032 CONFIG_SYS_DTT_BUS_NUM
2034 If defined, then this indicates the I2C bus number for the DTT.
2035 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2037 CONFIG_SYS_I2C_DTT_ADDR:
2039 If defined, specifies the I2C address of the DTT device.
2040 If not defined, then U-Boot uses predefined value for
2041 specified DTT device.
2045 Define this option if you want to use Freescale's I2C driver in
2046 drivers/i2c/fsl_i2c.c.
2050 Define this option if you have I2C devices reached over 1 .. n
2051 I2C Muxes like the pca9544a. This option addes a new I2C
2052 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2053 new I2C Bus to the existing I2C Busses. If you select the
2054 new Bus with "i2c dev", u-bbot sends first the commandos for
2055 the muxes to activate this new "bus".
2057 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2061 Adding a new I2C Bus reached over 2 pca9544a muxes
2062 The First mux with address 70 and channel 6
2063 The Second mux with address 71 and channel 4
2065 => i2c bus pca9544a:70:6:pca9544a:71:4
2067 Use the "i2c bus" command without parameter, to get a list
2068 of I2C Busses with muxes:
2071 Busses reached over muxes:
2073 reached over Mux(es):
2076 reached over Mux(es):
2081 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2082 u-boot first sends the command to the mux@70 to enable
2083 channel 6, and then the command to the mux@71 to enable
2086 After that, you can use the "normal" i2c commands as
2087 usual to communicate with your I2C devices behind
2090 This option is actually implemented for the bitbanging
2091 algorithm in common/soft_i2c.c and for the Hardware I2C
2092 Bus on the MPC8260. But it should be not so difficult
2093 to add this option to other architectures.
2095 CONFIG_SOFT_I2C_READ_REPEATED_START
2097 defining this will force the i2c_read() function in
2098 the soft_i2c driver to perform an I2C repeated start
2099 between writing the address pointer and reading the
2100 data. If this define is omitted the default behaviour
2101 of doing a stop-start sequence will be used. Most I2C
2102 devices can use either method, but some require one or
2105 - SPI Support: CONFIG_SPI
2107 Enables SPI driver (so far only tested with
2108 SPI EEPROM, also an instance works with Crystal A/D and
2109 D/As on the SACSng board)
2113 Enables the driver for SPI controller on SuperH. Currently
2114 only SH7757 is supported.
2118 Enables extended (16-bit) SPI EEPROM addressing.
2119 (symmetrical to CONFIG_I2C_X)
2123 Enables a software (bit-bang) SPI driver rather than
2124 using hardware support. This is a general purpose
2125 driver that only requires three general I/O port pins
2126 (two outputs, one input) to function. If this is
2127 defined, the board configuration must define several
2128 SPI configuration items (port pins to use, etc). For
2129 an example, see include/configs/sacsng.h.
2133 Enables a hardware SPI driver for general-purpose reads
2134 and writes. As with CONFIG_SOFT_SPI, the board configuration
2135 must define a list of chip-select function pointers.
2136 Currently supported on some MPC8xxx processors. For an
2137 example, see include/configs/mpc8349emds.h.
2141 Enables the driver for the SPI controllers on i.MX and MXC
2142 SoCs. Currently i.MX31/35/51 are supported.
2144 - FPGA Support: CONFIG_FPGA
2146 Enables FPGA subsystem.
2148 CONFIG_FPGA_<vendor>
2150 Enables support for specific chip vendors.
2153 CONFIG_FPGA_<family>
2155 Enables support for FPGA family.
2156 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2160 Specify the number of FPGA devices to support.
2162 CONFIG_SYS_FPGA_PROG_FEEDBACK
2164 Enable printing of hash marks during FPGA configuration.
2166 CONFIG_SYS_FPGA_CHECK_BUSY
2168 Enable checks on FPGA configuration interface busy
2169 status by the configuration function. This option
2170 will require a board or device specific function to
2175 If defined, a function that provides delays in the FPGA
2176 configuration driver.
2178 CONFIG_SYS_FPGA_CHECK_CTRLC
2179 Allow Control-C to interrupt FPGA configuration
2181 CONFIG_SYS_FPGA_CHECK_ERROR
2183 Check for configuration errors during FPGA bitfile
2184 loading. For example, abort during Virtex II
2185 configuration if the INIT_B line goes low (which
2186 indicated a CRC error).
2188 CONFIG_SYS_FPGA_WAIT_INIT
2190 Maximum time to wait for the INIT_B line to deassert
2191 after PROB_B has been deasserted during a Virtex II
2192 FPGA configuration sequence. The default time is 500
2195 CONFIG_SYS_FPGA_WAIT_BUSY
2197 Maximum time to wait for BUSY to deassert during
2198 Virtex II FPGA configuration. The default is 5 ms.
2200 CONFIG_SYS_FPGA_WAIT_CONFIG
2202 Time to wait after FPGA configuration. The default is
2205 - Configuration Management:
2208 If defined, this string will be added to the U-Boot
2209 version information (U_BOOT_VERSION)
2211 - Vendor Parameter Protection:
2213 U-Boot considers the values of the environment
2214 variables "serial#" (Board Serial Number) and
2215 "ethaddr" (Ethernet Address) to be parameters that
2216 are set once by the board vendor / manufacturer, and
2217 protects these variables from casual modification by
2218 the user. Once set, these variables are read-only,
2219 and write or delete attempts are rejected. You can
2220 change this behaviour:
2222 If CONFIG_ENV_OVERWRITE is #defined in your config
2223 file, the write protection for vendor parameters is
2224 completely disabled. Anybody can change or delete
2227 Alternatively, if you #define _both_ CONFIG_ETHADDR
2228 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2229 Ethernet address is installed in the environment,
2230 which can be changed exactly ONCE by the user. [The
2231 serial# is unaffected by this, i. e. it remains
2234 The same can be accomplished in a more flexible way
2235 for any variable by configuring the type of access
2236 to allow for those variables in the ".flags" variable
2237 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2242 Define this variable to enable the reservation of
2243 "protected RAM", i. e. RAM which is not overwritten
2244 by U-Boot. Define CONFIG_PRAM to hold the number of
2245 kB you want to reserve for pRAM. You can overwrite
2246 this default value by defining an environment
2247 variable "pram" to the number of kB you want to
2248 reserve. Note that the board info structure will
2249 still show the full amount of RAM. If pRAM is
2250 reserved, a new environment variable "mem" will
2251 automatically be defined to hold the amount of
2252 remaining RAM in a form that can be passed as boot
2253 argument to Linux, for instance like that:
2255 setenv bootargs ... mem=\${mem}
2258 This way you can tell Linux not to use this memory,
2259 either, which results in a memory region that will
2260 not be affected by reboots.
2262 *WARNING* If your board configuration uses automatic
2263 detection of the RAM size, you must make sure that
2264 this memory test is non-destructive. So far, the
2265 following board configurations are known to be
2268 IVMS8, IVML24, SPD8xx, TQM8xxL,
2269 HERMES, IP860, RPXlite, LWMON,
2272 - Access to physical memory region (> 4GB)
2273 Some basic support is provided for operations on memory not
2274 normally accessible to U-Boot - e.g. some architectures
2275 support access to more than 4GB of memory on 32-bit
2276 machines using physical address extension or similar.
2277 Define CONFIG_PHYSMEM to access this basic support, which
2278 currently only supports clearing the memory.
2283 Define this variable to stop the system in case of a
2284 fatal error, so that you have to reset it manually.
2285 This is probably NOT a good idea for an embedded
2286 system where you want the system to reboot
2287 automatically as fast as possible, but it may be
2288 useful during development since you can try to debug
2289 the conditions that lead to the situation.
2291 CONFIG_NET_RETRY_COUNT
2293 This variable defines the number of retries for
2294 network operations like ARP, RARP, TFTP, or BOOTP
2295 before giving up the operation. If not defined, a
2296 default value of 5 is used.
2300 Timeout waiting for an ARP reply in milliseconds.
2304 Timeout in milliseconds used in NFS protocol.
2305 If you encounter "ERROR: Cannot umount" in nfs command,
2306 try longer timeout such as
2307 #define CONFIG_NFS_TIMEOUT 10000UL
2309 - Command Interpreter:
2310 CONFIG_AUTO_COMPLETE
2312 Enable auto completion of commands using TAB.
2314 Note that this feature has NOT been implemented yet
2315 for the "hush" shell.
2318 CONFIG_SYS_HUSH_PARSER
2320 Define this variable to enable the "hush" shell (from
2321 Busybox) as command line interpreter, thus enabling
2322 powerful command line syntax like
2323 if...then...else...fi conditionals or `&&' and '||'
2324 constructs ("shell scripts").
2326 If undefined, you get the old, much simpler behaviour
2327 with a somewhat smaller memory footprint.
2330 CONFIG_SYS_PROMPT_HUSH_PS2
2332 This defines the secondary prompt string, which is
2333 printed when the command interpreter needs more input
2334 to complete a command. Usually "> ".
2338 In the current implementation, the local variables
2339 space and global environment variables space are
2340 separated. Local variables are those you define by
2341 simply typing `name=value'. To access a local
2342 variable later on, you have write `$name' or
2343 `${name}'; to execute the contents of a variable
2344 directly type `$name' at the command prompt.
2346 Global environment variables are those you use
2347 setenv/printenv to work with. To run a command stored
2348 in such a variable, you need to use the run command,
2349 and you must not use the '$' sign to access them.
2351 To store commands and special characters in a
2352 variable, please use double quotation marks
2353 surrounding the whole text of the variable, instead
2354 of the backslashes before semicolons and special
2357 - Commandline Editing and History:
2358 CONFIG_CMDLINE_EDITING
2360 Enable editing and History functions for interactive
2361 commandline input operations
2363 - Default Environment:
2364 CONFIG_EXTRA_ENV_SETTINGS
2366 Define this to contain any number of null terminated
2367 strings (variable = value pairs) that will be part of
2368 the default environment compiled into the boot image.
2370 For example, place something like this in your
2371 board's config file:
2373 #define CONFIG_EXTRA_ENV_SETTINGS \
2377 Warning: This method is based on knowledge about the
2378 internal format how the environment is stored by the
2379 U-Boot code. This is NOT an official, exported
2380 interface! Although it is unlikely that this format
2381 will change soon, there is no guarantee either.
2382 You better know what you are doing here.
2384 Note: overly (ab)use of the default environment is
2385 discouraged. Make sure to check other ways to preset
2386 the environment like the "source" command or the
2389 CONFIG_ENV_VARS_UBOOT_CONFIG
2391 Define this in order to add variables describing the
2392 U-Boot build configuration to the default environment.
2393 These will be named arch, cpu, board, vendor, and soc.
2395 Enabling this option will cause the following to be defined:
2403 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2405 Define this in order to add variables describing certain
2406 run-time determined information about the hardware to the
2407 environment. These will be named board_name, board_rev.
2409 CONFIG_DELAY_ENVIRONMENT
2411 Normally the environment is loaded when the board is
2412 intialised so that it is available to U-Boot. This inhibits
2413 that so that the environment is not available until
2414 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2415 this is instead controlled by the value of
2416 /config/load-environment.
2418 - DataFlash Support:
2419 CONFIG_HAS_DATAFLASH
2421 Defining this option enables DataFlash features and
2422 allows to read/write in Dataflash via the standard
2425 - Serial Flash support
2428 Defining this option enables SPI flash commands
2429 'sf probe/read/write/erase/update'.
2431 Usage requires an initial 'probe' to define the serial
2432 flash parameters, followed by read/write/erase/update
2435 The following defaults may be provided by the platform
2436 to handle the common case when only a single serial
2437 flash is present on the system.
2439 CONFIG_SF_DEFAULT_BUS Bus identifier
2440 CONFIG_SF_DEFAULT_CS Chip-select
2441 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2442 CONFIG_SF_DEFAULT_SPEED in Hz
2446 Define this option to include a destructive SPI flash
2449 - SystemACE Support:
2452 Adding this option adds support for Xilinx SystemACE
2453 chips attached via some sort of local bus. The address
2454 of the chip must also be defined in the
2455 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2457 #define CONFIG_SYSTEMACE
2458 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2460 When SystemACE support is added, the "ace" device type
2461 becomes available to the fat commands, i.e. fatls.
2463 - TFTP Fixed UDP Port:
2466 If this is defined, the environment variable tftpsrcp
2467 is used to supply the TFTP UDP source port value.
2468 If tftpsrcp isn't defined, the normal pseudo-random port
2469 number generator is used.
2471 Also, the environment variable tftpdstp is used to supply
2472 the TFTP UDP destination port value. If tftpdstp isn't
2473 defined, the normal port 69 is used.
2475 The purpose for tftpsrcp is to allow a TFTP server to
2476 blindly start the TFTP transfer using the pre-configured
2477 target IP address and UDP port. This has the effect of
2478 "punching through" the (Windows XP) firewall, allowing
2479 the remainder of the TFTP transfer to proceed normally.
2480 A better solution is to properly configure the firewall,
2481 but sometimes that is not allowed.
2486 This enables a generic 'hash' command which can produce
2487 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2491 Enable the hash verify command (hash -v). This adds to code
2494 CONFIG_SHA1 - support SHA1 hashing
2495 CONFIG_SHA256 - support SHA256 hashing
2497 Note: There is also a sha1sum command, which should perhaps
2498 be deprecated in favour of 'hash sha1'.
2500 - Show boot progress:
2501 CONFIG_SHOW_BOOT_PROGRESS
2503 Defining this option allows to add some board-
2504 specific code (calling a user-provided function
2505 "show_boot_progress(int)") that enables you to show
2506 the system's boot progress on some display (for
2507 example, some LED's) on your board. At the moment,
2508 the following checkpoints are implemented:
2510 - Detailed boot stage timing
2512 Define this option to get detailed timing of each stage
2513 of the boot process.
2515 CONFIG_BOOTSTAGE_USER_COUNT
2516 This is the number of available user bootstage records.
2517 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2518 a new ID will be allocated from this stash. If you exceed
2519 the limit, recording will stop.
2521 CONFIG_BOOTSTAGE_REPORT
2522 Define this to print a report before boot, similar to this:
2524 Timer summary in microseconds:
2527 3,575,678 3,575,678 board_init_f start
2528 3,575,695 17 arch_cpu_init A9
2529 3,575,777 82 arch_cpu_init done
2530 3,659,598 83,821 board_init_r start
2531 3,910,375 250,777 main_loop
2532 29,916,167 26,005,792 bootm_start
2533 30,361,327 445,160 start_kernel
2535 CONFIG_CMD_BOOTSTAGE
2536 Add a 'bootstage' command which supports printing a report
2537 and un/stashing of bootstage data.
2539 CONFIG_BOOTSTAGE_FDT
2540 Stash the bootstage information in the FDT. A root 'bootstage'
2541 node is created with each bootstage id as a child. Each child
2542 has a 'name' property and either 'mark' containing the
2543 mark time in microsecond, or 'accum' containing the
2544 accumulated time for that bootstage id in microseconds.
2549 name = "board_init_f";
2558 Code in the Linux kernel can find this in /proc/devicetree.
2560 Legacy uImage format:
2563 1 common/cmd_bootm.c before attempting to boot an image
2564 -1 common/cmd_bootm.c Image header has bad magic number
2565 2 common/cmd_bootm.c Image header has correct magic number
2566 -2 common/cmd_bootm.c Image header has bad checksum
2567 3 common/cmd_bootm.c Image header has correct checksum
2568 -3 common/cmd_bootm.c Image data has bad checksum
2569 4 common/cmd_bootm.c Image data has correct checksum
2570 -4 common/cmd_bootm.c Image is for unsupported architecture
2571 5 common/cmd_bootm.c Architecture check OK
2572 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2573 6 common/cmd_bootm.c Image Type check OK
2574 -6 common/cmd_bootm.c gunzip uncompression error
2575 -7 common/cmd_bootm.c Unimplemented compression type
2576 7 common/cmd_bootm.c Uncompression OK
2577 8 common/cmd_bootm.c No uncompress/copy overwrite error
2578 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2580 9 common/image.c Start initial ramdisk verification
2581 -10 common/image.c Ramdisk header has bad magic number
2582 -11 common/image.c Ramdisk header has bad checksum
2583 10 common/image.c Ramdisk header is OK
2584 -12 common/image.c Ramdisk data has bad checksum
2585 11 common/image.c Ramdisk data has correct checksum
2586 12 common/image.c Ramdisk verification complete, start loading
2587 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2588 13 common/image.c Start multifile image verification
2589 14 common/image.c No initial ramdisk, no multifile, continue.
2591 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2593 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2594 -31 post/post.c POST test failed, detected by post_output_backlog()
2595 -32 post/post.c POST test failed, detected by post_run_single()
2597 34 common/cmd_doc.c before loading a Image from a DOC device
2598 -35 common/cmd_doc.c Bad usage of "doc" command
2599 35 common/cmd_doc.c correct usage of "doc" command
2600 -36 common/cmd_doc.c No boot device
2601 36 common/cmd_doc.c correct boot device
2602 -37 common/cmd_doc.c Unknown Chip ID on boot device
2603 37 common/cmd_doc.c correct chip ID found, device available
2604 -38 common/cmd_doc.c Read Error on boot device
2605 38 common/cmd_doc.c reading Image header from DOC device OK
2606 -39 common/cmd_doc.c Image header has bad magic number
2607 39 common/cmd_doc.c Image header has correct magic number
2608 -40 common/cmd_doc.c Error reading Image from DOC device
2609 40 common/cmd_doc.c Image header has correct magic number
2610 41 common/cmd_ide.c before loading a Image from a IDE device
2611 -42 common/cmd_ide.c Bad usage of "ide" command
2612 42 common/cmd_ide.c correct usage of "ide" command
2613 -43 common/cmd_ide.c No boot device
2614 43 common/cmd_ide.c boot device found
2615 -44 common/cmd_ide.c Device not available
2616 44 common/cmd_ide.c Device available
2617 -45 common/cmd_ide.c wrong partition selected
2618 45 common/cmd_ide.c partition selected
2619 -46 common/cmd_ide.c Unknown partition table
2620 46 common/cmd_ide.c valid partition table found
2621 -47 common/cmd_ide.c Invalid partition type
2622 47 common/cmd_ide.c correct partition type
2623 -48 common/cmd_ide.c Error reading Image Header on boot device
2624 48 common/cmd_ide.c reading Image Header from IDE device OK
2625 -49 common/cmd_ide.c Image header has bad magic number
2626 49 common/cmd_ide.c Image header has correct magic number
2627 -50 common/cmd_ide.c Image header has bad checksum
2628 50 common/cmd_ide.c Image header has correct checksum
2629 -51 common/cmd_ide.c Error reading Image from IDE device
2630 51 common/cmd_ide.c reading Image from IDE device OK
2631 52 common/cmd_nand.c before loading a Image from a NAND device
2632 -53 common/cmd_nand.c Bad usage of "nand" command
2633 53 common/cmd_nand.c correct usage of "nand" command
2634 -54 common/cmd_nand.c No boot device
2635 54 common/cmd_nand.c boot device found
2636 -55 common/cmd_nand.c Unknown Chip ID on boot device
2637 55 common/cmd_nand.c correct chip ID found, device available
2638 -56 common/cmd_nand.c Error reading Image Header on boot device
2639 56 common/cmd_nand.c reading Image Header from NAND device OK
2640 -57 common/cmd_nand.c Image header has bad magic number
2641 57 common/cmd_nand.c Image header has correct magic number
2642 -58 common/cmd_nand.c Error reading Image from NAND device
2643 58 common/cmd_nand.c reading Image from NAND device OK
2645 -60 common/env_common.c Environment has a bad CRC, using default
2647 64 net/eth.c starting with Ethernet configuration.
2648 -64 net/eth.c no Ethernet found.
2649 65 net/eth.c Ethernet found.
2651 -80 common/cmd_net.c usage wrong
2652 80 common/cmd_net.c before calling NetLoop()
2653 -81 common/cmd_net.c some error in NetLoop() occurred
2654 81 common/cmd_net.c NetLoop() back without error
2655 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2656 82 common/cmd_net.c trying automatic boot
2657 83 common/cmd_net.c running "source" command
2658 -83 common/cmd_net.c some error in automatic boot or "source" command
2659 84 common/cmd_net.c end without errors
2664 100 common/cmd_bootm.c Kernel FIT Image has correct format
2665 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2666 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2667 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2668 102 common/cmd_bootm.c Kernel unit name specified
2669 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2670 103 common/cmd_bootm.c Found configuration node
2671 104 common/cmd_bootm.c Got kernel subimage node offset
2672 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2673 105 common/cmd_bootm.c Kernel subimage hash verification OK
2674 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2675 106 common/cmd_bootm.c Architecture check OK
2676 -106 common/cmd_bootm.c Kernel subimage has wrong type
2677 107 common/cmd_bootm.c Kernel subimage type OK
2678 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2679 108 common/cmd_bootm.c Got kernel subimage data/size
2680 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2681 -109 common/cmd_bootm.c Can't get kernel subimage type
2682 -110 common/cmd_bootm.c Can't get kernel subimage comp
2683 -111 common/cmd_bootm.c Can't get kernel subimage os
2684 -112 common/cmd_bootm.c Can't get kernel subimage load address
2685 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2687 120 common/image.c Start initial ramdisk verification
2688 -120 common/image.c Ramdisk FIT image has incorrect format
2689 121 common/image.c Ramdisk FIT image has correct format
2690 122 common/image.c No ramdisk subimage unit name, using configuration
2691 -122 common/image.c Can't get configuration for ramdisk subimage
2692 123 common/image.c Ramdisk unit name specified
2693 -124 common/image.c Can't get ramdisk subimage node offset
2694 125 common/image.c Got ramdisk subimage node offset
2695 -125 common/image.c Ramdisk subimage hash verification failed
2696 126 common/image.c Ramdisk subimage hash verification OK
2697 -126 common/image.c Ramdisk subimage for unsupported architecture
2698 127 common/image.c Architecture check OK
2699 -127 common/image.c Can't get ramdisk subimage data/size
2700 128 common/image.c Got ramdisk subimage data/size
2701 129 common/image.c Can't get ramdisk load address
2702 -129 common/image.c Got ramdisk load address
2704 -130 common/cmd_doc.c Incorrect FIT image format
2705 131 common/cmd_doc.c FIT image format OK
2707 -140 common/cmd_ide.c Incorrect FIT image format
2708 141 common/cmd_ide.c FIT image format OK
2710 -150 common/cmd_nand.c Incorrect FIT image format
2711 151 common/cmd_nand.c FIT image format OK
2713 - FIT image support:
2715 Enable support for the FIT uImage format.
2717 CONFIG_FIT_BEST_MATCH
2718 When no configuration is explicitly selected, default to the
2719 one whose fdt's compatibility field best matches that of
2720 U-Boot itself. A match is considered "best" if it matches the
2721 most specific compatibility entry of U-Boot's fdt's root node.
2722 The order of entries in the configuration's fdt is ignored.
2724 - Standalone program support:
2725 CONFIG_STANDALONE_LOAD_ADDR
2727 This option defines a board specific value for the
2728 address where standalone program gets loaded, thus
2729 overwriting the architecture dependent default
2732 - Frame Buffer Address:
2735 Define CONFIG_FB_ADDR if you want to use specific
2736 address for frame buffer. This is typically the case
2737 when using a graphics controller has separate video
2738 memory. U-Boot will then place the frame buffer at
2739 the given address instead of dynamically reserving it
2740 in system RAM by calling lcd_setmem(), which grabs
2741 the memory for the frame buffer depending on the
2742 configured panel size.
2744 Please see board_init_f function.
2746 - Automatic software updates via TFTP server
2748 CONFIG_UPDATE_TFTP_CNT_MAX
2749 CONFIG_UPDATE_TFTP_MSEC_MAX
2751 These options enable and control the auto-update feature;
2752 for a more detailed description refer to doc/README.update.
2754 - MTD Support (mtdparts command, UBI support)
2757 Adds the MTD device infrastructure from the Linux kernel.
2758 Needed for mtdparts command support.
2760 CONFIG_MTD_PARTITIONS
2762 Adds the MTD partitioning infrastructure from the Linux
2763 kernel. Needed for UBI support.
2767 Enable building of SPL globally.
2770 LDSCRIPT for linking the SPL binary.
2773 Maximum binary size (text, data and rodata) of the SPL binary.
2775 CONFIG_SPL_TEXT_BASE
2776 TEXT_BASE for linking the SPL binary.
2778 CONFIG_SPL_RELOC_TEXT_BASE
2779 Address to relocate to. If unspecified, this is equal to
2780 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2782 CONFIG_SPL_BSS_START_ADDR
2783 Link address for the BSS within the SPL binary.
2785 CONFIG_SPL_BSS_MAX_SIZE
2786 Maximum binary size of the BSS section of the SPL binary.
2789 Adress of the start of the stack SPL will use
2791 CONFIG_SPL_RELOC_STACK
2792 Adress of the start of the stack SPL will use after
2793 relocation. If unspecified, this is equal to
2796 CONFIG_SYS_SPL_MALLOC_START
2797 Starting address of the malloc pool used in SPL.
2799 CONFIG_SYS_SPL_MALLOC_SIZE
2800 The size of the malloc pool used in SPL.
2802 CONFIG_SPL_FRAMEWORK
2803 Enable the SPL framework under common/. This framework
2804 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2805 NAND loading of the Linux Kernel.
2807 CONFIG_SPL_DISPLAY_PRINT
2808 For ARM, enable an optional function to print more information
2809 about the running system.
2811 CONFIG_SPL_INIT_MINIMAL
2812 Arch init code should be built for a very small image
2814 CONFIG_SPL_LIBCOMMON_SUPPORT
2815 Support for common/libcommon.o in SPL binary
2817 CONFIG_SPL_LIBDISK_SUPPORT
2818 Support for disk/libdisk.o in SPL binary
2820 CONFIG_SPL_I2C_SUPPORT
2821 Support for drivers/i2c/libi2c.o in SPL binary
2823 CONFIG_SPL_GPIO_SUPPORT
2824 Support for drivers/gpio/libgpio.o in SPL binary
2826 CONFIG_SPL_MMC_SUPPORT
2827 Support for drivers/mmc/libmmc.o in SPL binary
2829 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2830 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2831 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2832 Address, size and partition on the MMC to load U-Boot from
2833 when the MMC is being used in raw mode.
2835 CONFIG_SPL_FAT_SUPPORT
2836 Support for fs/fat/libfat.o in SPL binary
2838 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2839 Filename to read to load U-Boot when reading from FAT
2841 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2842 Set this for NAND SPL on PPC mpc83xx targets, so that
2843 start.S waits for the rest of the SPL to load before
2844 continuing (the hardware starts execution after just
2845 loading the first page rather than the full 4K).
2847 CONFIG_SPL_NAND_BASE
2848 Include nand_base.c in the SPL. Requires
2849 CONFIG_SPL_NAND_DRIVERS.
2851 CONFIG_SPL_NAND_DRIVERS
2852 SPL uses normal NAND drivers, not minimal drivers.
2855 Include standard software ECC in the SPL
2857 CONFIG_SPL_NAND_SIMPLE
2858 Support for NAND boot using simple NAND drivers that
2859 expose the cmd_ctrl() interface.
2861 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2862 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2863 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2864 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2865 CONFIG_SYS_NAND_ECCBYTES
2866 Defines the size and behavior of the NAND that SPL uses
2869 CONFIG_SYS_NAND_U_BOOT_OFFS
2870 Location in NAND to read U-Boot from
2872 CONFIG_SYS_NAND_U_BOOT_DST
2873 Location in memory to load U-Boot to
2875 CONFIG_SYS_NAND_U_BOOT_SIZE
2876 Size of image to load
2878 CONFIG_SYS_NAND_U_BOOT_START
2879 Entry point in loaded image to jump to
2881 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2882 Define this if you need to first read the OOB and then the
2883 data. This is used for example on davinci plattforms.
2885 CONFIG_SPL_OMAP3_ID_NAND
2886 Support for an OMAP3-specific set of functions to return the
2887 ID and MFR of the first attached NAND chip, if present.
2889 CONFIG_SPL_SERIAL_SUPPORT
2890 Support for drivers/serial/libserial.o in SPL binary
2892 CONFIG_SPL_SPI_FLASH_SUPPORT
2893 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2895 CONFIG_SPL_SPI_SUPPORT
2896 Support for drivers/spi/libspi.o in SPL binary
2898 CONFIG_SPL_RAM_DEVICE
2899 Support for running image already present in ram, in SPL binary
2901 CONFIG_SPL_LIBGENERIC_SUPPORT
2902 Support for lib/libgeneric.o in SPL binary
2905 Linker address to which the SPL should be padded before
2906 appending the SPL payload.
2909 Final target image containing SPL and payload. Some SPLs
2910 use an arch-specific makefile fragment instead, for
2911 example if more than one image needs to be produced.
2916 [so far only for SMDK2400 boards]
2918 - Modem support enable:
2919 CONFIG_MODEM_SUPPORT
2921 - RTS/CTS Flow control enable:
2924 - Modem debug support:
2925 CONFIG_MODEM_SUPPORT_DEBUG
2927 Enables debugging stuff (char screen[1024], dbg())
2928 for modem support. Useful only with BDI2000.
2930 - Interrupt support (PPC):
2932 There are common interrupt_init() and timer_interrupt()
2933 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2934 for CPU specific initialization. interrupt_init_cpu()
2935 should set decrementer_count to appropriate value. If
2936 CPU resets decrementer automatically after interrupt
2937 (ppc4xx) it should set decrementer_count to zero.
2938 timer_interrupt() calls timer_interrupt_cpu() for CPU
2939 specific handling. If board has watchdog / status_led
2940 / other_activity_monitor it works automatically from
2941 general timer_interrupt().
2945 In the target system modem support is enabled when a
2946 specific key (key combination) is pressed during
2947 power-on. Otherwise U-Boot will boot normally
2948 (autoboot). The key_pressed() function is called from
2949 board_init(). Currently key_pressed() is a dummy
2950 function, returning 1 and thus enabling modem
2953 If there are no modem init strings in the
2954 environment, U-Boot proceed to autoboot; the
2955 previous output (banner, info printfs) will be
2958 See also: doc/README.Modem
2960 Board initialization settings:
2961 ------------------------------
2963 During Initialization u-boot calls a number of board specific functions
2964 to allow the preparation of board specific prerequisites, e.g. pin setup
2965 before drivers are initialized. To enable these callbacks the
2966 following configuration macros have to be defined. Currently this is
2967 architecture specific, so please check arch/your_architecture/lib/board.c
2968 typically in board_init_f() and board_init_r().
2970 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2971 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2972 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2973 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2975 Configuration Settings:
2976 -----------------------
2978 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2979 undefine this when you're short of memory.
2981 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2982 width of the commands listed in the 'help' command output.
2984 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2985 prompt for user input.
2987 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2989 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2991 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2993 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2994 the application (usually a Linux kernel) when it is
2997 - CONFIG_SYS_BAUDRATE_TABLE:
2998 List of legal baudrate settings for this board.
3000 - CONFIG_SYS_CONSOLE_INFO_QUIET
3001 Suppress display of console information at boot.
3003 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3004 If the board specific function
3005 extern int overwrite_console (void);
3006 returns 1, the stdin, stderr and stdout are switched to the
3007 serial port, else the settings in the environment are used.
3009 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3010 Enable the call to overwrite_console().
3012 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3013 Enable overwrite of previous console environment settings.
3015 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3016 Begin and End addresses of the area used by the
3019 - CONFIG_SYS_ALT_MEMTEST:
3020 Enable an alternate, more extensive memory test.
3022 - CONFIG_SYS_MEMTEST_SCRATCH:
3023 Scratch address used by the alternate memory test
3024 You only need to set this if address zero isn't writeable
3026 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3027 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3028 this specified memory area will get subtracted from the top
3029 (end) of RAM and won't get "touched" at all by U-Boot. By
3030 fixing up gd->ram_size the Linux kernel should gets passed
3031 the now "corrected" memory size and won't touch it either.
3032 This should work for arch/ppc and arch/powerpc. Only Linux
3033 board ports in arch/powerpc with bootwrapper support that
3034 recalculate the memory size from the SDRAM controller setup
3035 will have to get fixed in Linux additionally.
3037 This option can be used as a workaround for the 440EPx/GRx
3038 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3041 WARNING: Please make sure that this value is a multiple of
3042 the Linux page size (normally 4k). If this is not the case,
3043 then the end address of the Linux memory will be located at a
3044 non page size aligned address and this could cause major
3047 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3048 Enable temporary baudrate change while serial download
3050 - CONFIG_SYS_SDRAM_BASE:
3051 Physical start address of SDRAM. _Must_ be 0 here.
3053 - CONFIG_SYS_MBIO_BASE:
3054 Physical start address of Motherboard I/O (if using a
3057 - CONFIG_SYS_FLASH_BASE:
3058 Physical start address of Flash memory.
3060 - CONFIG_SYS_MONITOR_BASE:
3061 Physical start address of boot monitor code (set by
3062 make config files to be same as the text base address
3063 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3064 CONFIG_SYS_FLASH_BASE when booting from flash.
3066 - CONFIG_SYS_MONITOR_LEN:
3067 Size of memory reserved for monitor code, used to
3068 determine _at_compile_time_ (!) if the environment is
3069 embedded within the U-Boot image, or in a separate
3072 - CONFIG_SYS_MALLOC_LEN:
3073 Size of DRAM reserved for malloc() use.
3075 - CONFIG_SYS_BOOTM_LEN:
3076 Normally compressed uImages are limited to an
3077 uncompressed size of 8 MBytes. If this is not enough,
3078 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3079 to adjust this setting to your needs.
3081 - CONFIG_SYS_BOOTMAPSZ:
3082 Maximum size of memory mapped by the startup code of
3083 the Linux kernel; all data that must be processed by
3084 the Linux kernel (bd_info, boot arguments, FDT blob if
3085 used) must be put below this limit, unless "bootm_low"
3086 enviroment variable is defined and non-zero. In such case
3087 all data for the Linux kernel must be between "bootm_low"
3088 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3089 variable "bootm_mapsize" will override the value of
3090 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3091 then the value in "bootm_size" will be used instead.
3093 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3094 Enable initrd_high functionality. If defined then the
3095 initrd_high feature is enabled and the bootm ramdisk subcommand
3098 - CONFIG_SYS_BOOT_GET_CMDLINE:
3099 Enables allocating and saving kernel cmdline in space between
3100 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3102 - CONFIG_SYS_BOOT_GET_KBD:
3103 Enables allocating and saving a kernel copy of the bd_info in
3104 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3106 - CONFIG_SYS_MAX_FLASH_BANKS:
3107 Max number of Flash memory banks
3109 - CONFIG_SYS_MAX_FLASH_SECT:
3110 Max number of sectors on a Flash chip
3112 - CONFIG_SYS_FLASH_ERASE_TOUT:
3113 Timeout for Flash erase operations (in ms)
3115 - CONFIG_SYS_FLASH_WRITE_TOUT:
3116 Timeout for Flash write operations (in ms)
3118 - CONFIG_SYS_FLASH_LOCK_TOUT
3119 Timeout for Flash set sector lock bit operation (in ms)
3121 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3122 Timeout for Flash clear lock bits operation (in ms)
3124 - CONFIG_SYS_FLASH_PROTECTION
3125 If defined, hardware flash sectors protection is used
3126 instead of U-Boot software protection.
3128 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3130 Enable TFTP transfers directly to flash memory;
3131 without this option such a download has to be
3132 performed in two steps: (1) download to RAM, and (2)
3133 copy from RAM to flash.
3135 The two-step approach is usually more reliable, since
3136 you can check if the download worked before you erase
3137 the flash, but in some situations (when system RAM is
3138 too limited to allow for a temporary copy of the
3139 downloaded image) this option may be very useful.
3141 - CONFIG_SYS_FLASH_CFI:
3142 Define if the flash driver uses extra elements in the
3143 common flash structure for storing flash geometry.
3145 - CONFIG_FLASH_CFI_DRIVER
3146 This option also enables the building of the cfi_flash driver
3147 in the drivers directory
3149 - CONFIG_FLASH_CFI_MTD
3150 This option enables the building of the cfi_mtd driver
3151 in the drivers directory. The driver exports CFI flash
3154 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3155 Use buffered writes to flash.
3157 - CONFIG_FLASH_SPANSION_S29WS_N
3158 s29ws-n MirrorBit flash has non-standard addresses for buffered
3161 - CONFIG_SYS_FLASH_QUIET_TEST
3162 If this option is defined, the common CFI flash doesn't
3163 print it's warning upon not recognized FLASH banks. This
3164 is useful, if some of the configured banks are only
3165 optionally available.
3167 - CONFIG_FLASH_SHOW_PROGRESS
3168 If defined (must be an integer), print out countdown
3169 digits and dots. Recommended value: 45 (9..1) for 80
3170 column displays, 15 (3..1) for 40 column displays.
3172 - CONFIG_SYS_RX_ETH_BUFFER:
3173 Defines the number of Ethernet receive buffers. On some
3174 Ethernet controllers it is recommended to set this value
3175 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3176 buffers can be full shortly after enabling the interface
3177 on high Ethernet traffic.
3178 Defaults to 4 if not defined.
3180 - CONFIG_ENV_MAX_ENTRIES
3182 Maximum number of entries in the hash table that is used
3183 internally to store the environment settings. The default
3184 setting is supposed to be generous and should work in most
3185 cases. This setting can be used to tune behaviour; see
3186 lib/hashtable.c for details.
3188 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3189 - CONFIG_ENV_FLAGS_LIST_STATIC
3190 Enable validation of the values given to enviroment variables when
3191 calling env set. Variables can be restricted to only decimal,
3192 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3193 the variables can also be restricted to IP address or MAC address.
3195 The format of the list is:
3196 type_attribute = [s|d|x|b|i|m]
3197 access_atribute = [a|r|o|c]
3198 attributes = type_attribute[access_atribute]
3199 entry = variable_name[:attributes]
3202 The type attributes are:
3203 s - String (default)
3206 b - Boolean ([1yYtT|0nNfF])
3210 The access attributes are:
3216 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3217 Define this to a list (string) to define the ".flags"
3218 envirnoment variable in the default or embedded environment.
3220 - CONFIG_ENV_FLAGS_LIST_STATIC
3221 Define this to a list (string) to define validation that
3222 should be done if an entry is not found in the ".flags"
3223 environment variable. To override a setting in the static
3224 list, simply add an entry for the same variable name to the
3227 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3228 If defined, don't allow the -f switch to env set override variable
3231 The following definitions that deal with the placement and management
3232 of environment data (variable area); in general, we support the
3233 following configurations:
3235 - CONFIG_BUILD_ENVCRC:
3237 Builds up envcrc with the target environment so that external utils
3238 may easily extract it and embed it in final U-Boot images.
3240 - CONFIG_ENV_IS_IN_FLASH:
3242 Define this if the environment is in flash memory.
3244 a) The environment occupies one whole flash sector, which is
3245 "embedded" in the text segment with the U-Boot code. This
3246 happens usually with "bottom boot sector" or "top boot
3247 sector" type flash chips, which have several smaller
3248 sectors at the start or the end. For instance, such a
3249 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3250 such a case you would place the environment in one of the
3251 4 kB sectors - with U-Boot code before and after it. With
3252 "top boot sector" type flash chips, you would put the
3253 environment in one of the last sectors, leaving a gap
3254 between U-Boot and the environment.
3256 - CONFIG_ENV_OFFSET:
3258 Offset of environment data (variable area) to the
3259 beginning of flash memory; for instance, with bottom boot
3260 type flash chips the second sector can be used: the offset
3261 for this sector is given here.
3263 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3267 This is just another way to specify the start address of
3268 the flash sector containing the environment (instead of
3271 - CONFIG_ENV_SECT_SIZE:
3273 Size of the sector containing the environment.
3276 b) Sometimes flash chips have few, equal sized, BIG sectors.
3277 In such a case you don't want to spend a whole sector for
3282 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3283 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3284 of this flash sector for the environment. This saves
3285 memory for the RAM copy of the environment.
3287 It may also save flash memory if you decide to use this
3288 when your environment is "embedded" within U-Boot code,
3289 since then the remainder of the flash sector could be used
3290 for U-Boot code. It should be pointed out that this is
3291 STRONGLY DISCOURAGED from a robustness point of view:
3292 updating the environment in flash makes it always
3293 necessary to erase the WHOLE sector. If something goes
3294 wrong before the contents has been restored from a copy in
3295 RAM, your target system will be dead.
3297 - CONFIG_ENV_ADDR_REDUND
3298 CONFIG_ENV_SIZE_REDUND
3300 These settings describe a second storage area used to hold
3301 a redundant copy of the environment data, so that there is
3302 a valid backup copy in case there is a power failure during
3303 a "saveenv" operation.
3305 BE CAREFUL! Any changes to the flash layout, and some changes to the
3306 source code will make it necessary to adapt <board>/u-boot.lds*
3310 - CONFIG_ENV_IS_IN_NVRAM:
3312 Define this if you have some non-volatile memory device
3313 (NVRAM, battery buffered SRAM) which you want to use for the
3319 These two #defines are used to determine the memory area you
3320 want to use for environment. It is assumed that this memory
3321 can just be read and written to, without any special
3324 BE CAREFUL! The first access to the environment happens quite early
3325 in U-Boot initalization (when we try to get the setting of for the
3326 console baudrate). You *MUST* have mapped your NVRAM area then, or
3329 Please note that even with NVRAM we still use a copy of the
3330 environment in RAM: we could work on NVRAM directly, but we want to
3331 keep settings there always unmodified except somebody uses "saveenv"
3332 to save the current settings.
3335 - CONFIG_ENV_IS_IN_EEPROM:
3337 Use this if you have an EEPROM or similar serial access
3338 device and a driver for it.
3340 - CONFIG_ENV_OFFSET:
3343 These two #defines specify the offset and size of the
3344 environment area within the total memory of your EEPROM.
3346 - CONFIG_SYS_I2C_EEPROM_ADDR:
3347 If defined, specified the chip address of the EEPROM device.
3348 The default address is zero.
3350 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3351 If defined, the number of bits used to address bytes in a
3352 single page in the EEPROM device. A 64 byte page, for example
3353 would require six bits.
3355 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3356 If defined, the number of milliseconds to delay between
3357 page writes. The default is zero milliseconds.
3359 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3360 The length in bytes of the EEPROM memory array address. Note
3361 that this is NOT the chip address length!
3363 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3364 EEPROM chips that implement "address overflow" are ones
3365 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3366 address and the extra bits end up in the "chip address" bit
3367 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3370 Note that we consider the length of the address field to
3371 still be one byte because the extra address bits are hidden
3372 in the chip address.
3374 - CONFIG_SYS_EEPROM_SIZE:
3375 The size in bytes of the EEPROM device.
3377 - CONFIG_ENV_EEPROM_IS_ON_I2C
3378 define this, if you have I2C and SPI activated, and your
3379 EEPROM, which holds the environment, is on the I2C bus.
3381 - CONFIG_I2C_ENV_EEPROM_BUS
3382 if you have an Environment on an EEPROM reached over
3383 I2C muxes, you can define here, how to reach this
3384 EEPROM. For example:
3386 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3388 EEPROM which holds the environment, is reached over
3389 a pca9547 i2c mux with address 0x70, channel 3.
3391 - CONFIG_ENV_IS_IN_DATAFLASH:
3393 Define this if you have a DataFlash memory device which you
3394 want to use for the environment.
3396 - CONFIG_ENV_OFFSET:
3400 These three #defines specify the offset and size of the
3401 environment area within the total memory of your DataFlash placed
3402 at the specified address.
3404 - CONFIG_ENV_IS_IN_REMOTE:
3406 Define this if you have a remote memory space which you
3407 want to use for the local device's environment.
3412 These two #defines specify the address and size of the
3413 environment area within the remote memory space. The
3414 local device can get the environment from remote memory
3415 space by SRIO or PCIE links.
3417 BE CAREFUL! For some special cases, the local device can not use
3418 "saveenv" command. For example, the local device will get the
3419 environment stored in a remote NOR flash by SRIO or PCIE link,
3420 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3422 - CONFIG_ENV_IS_IN_NAND:
3424 Define this if you have a NAND device which you want to use
3425 for the environment.
3427 - CONFIG_ENV_OFFSET:
3430 These two #defines specify the offset and size of the environment
3431 area within the first NAND device. CONFIG_ENV_OFFSET must be
3432 aligned to an erase block boundary.
3434 - CONFIG_ENV_OFFSET_REDUND (optional):
3436 This setting describes a second storage area of CONFIG_ENV_SIZE
3437 size used to hold a redundant copy of the environment data, so
3438 that there is a valid backup copy in case there is a power failure
3439 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3440 aligned to an erase block boundary.
3442 - CONFIG_ENV_RANGE (optional):
3444 Specifies the length of the region in which the environment
3445 can be written. This should be a multiple of the NAND device's
3446 block size. Specifying a range with more erase blocks than
3447 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3448 the range to be avoided.
3450 - CONFIG_ENV_OFFSET_OOB (optional):
3452 Enables support for dynamically retrieving the offset of the
3453 environment from block zero's out-of-band data. The
3454 "nand env.oob" command can be used to record this offset.
3455 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3456 using CONFIG_ENV_OFFSET_OOB.
3458 - CONFIG_NAND_ENV_DST
3460 Defines address in RAM to which the nand_spl code should copy the
3461 environment. If redundant environment is used, it will be copied to
3462 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3464 - CONFIG_SYS_SPI_INIT_OFFSET
3466 Defines offset to the initial SPI buffer area in DPRAM. The
3467 area is used at an early stage (ROM part) if the environment
3468 is configured to reside in the SPI EEPROM: We need a 520 byte
3469 scratch DPRAM area. It is used between the two initialization
3470 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3471 to be a good choice since it makes it far enough from the
3472 start of the data area as well as from the stack pointer.
3474 Please note that the environment is read-only until the monitor
3475 has been relocated to RAM and a RAM copy of the environment has been
3476 created; also, when using EEPROM you will have to use getenv_f()
3477 until then to read environment variables.
3479 The environment is protected by a CRC32 checksum. Before the monitor
3480 is relocated into RAM, as a result of a bad CRC you will be working
3481 with the compiled-in default environment - *silently*!!! [This is
3482 necessary, because the first environment variable we need is the
3483 "baudrate" setting for the console - if we have a bad CRC, we don't
3484 have any device yet where we could complain.]
3486 Note: once the monitor has been relocated, then it will complain if
3487 the default environment is used; a new CRC is computed as soon as you
3488 use the "saveenv" command to store a valid environment.
3490 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3491 Echo the inverted Ethernet link state to the fault LED.
3493 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3494 also needs to be defined.
3496 - CONFIG_SYS_FAULT_MII_ADDR:
3497 MII address of the PHY to check for the Ethernet link state.
3499 - CONFIG_NS16550_MIN_FUNCTIONS:
3500 Define this if you desire to only have use of the NS16550_init
3501 and NS16550_putc functions for the serial driver located at
3502 drivers/serial/ns16550.c. This option is useful for saving
3503 space for already greatly restricted images, including but not
3504 limited to NAND_SPL configurations.
3506 - CONFIG_DISPLAY_BOARDINFO
3507 Display information about the board that U-Boot is running on
3508 when U-Boot starts up. The board function checkboard() is called
3511 - CONFIG_DISPLAY_BOARDINFO_LATE
3512 Similar to the previous option, but display this information
3513 later, once stdio is running and output goes to the LCD, if
3516 Low Level (hardware related) configuration options:
3517 ---------------------------------------------------
3519 - CONFIG_SYS_CACHELINE_SIZE:
3520 Cache Line Size of the CPU.
3522 - CONFIG_SYS_DEFAULT_IMMR:
3523 Default address of the IMMR after system reset.
3525 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3526 and RPXsuper) to be able to adjust the position of
3527 the IMMR register after a reset.
3529 - CONFIG_SYS_CCSRBAR_DEFAULT:
3530 Default (power-on reset) physical address of CCSR on Freescale
3533 - CONFIG_SYS_CCSRBAR:
3534 Virtual address of CCSR. On a 32-bit build, this is typically
3535 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3537 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3538 for cross-platform code that uses that macro instead.
3540 - CONFIG_SYS_CCSRBAR_PHYS:
3541 Physical address of CCSR. CCSR can be relocated to a new
3542 physical address, if desired. In this case, this macro should
3543 be set to that address. Otherwise, it should be set to the
3544 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3545 is typically relocated on 36-bit builds. It is recommended
3546 that this macro be defined via the _HIGH and _LOW macros:
3548 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3549 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3551 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3552 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3553 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3554 used in assembly code, so it must not contain typecasts or
3555 integer size suffixes (e.g. "ULL").
3557 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3558 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3559 used in assembly code, so it must not contain typecasts or
3560 integer size suffixes (e.g. "ULL").
3562 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3563 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3564 forced to a value that ensures that CCSR is not relocated.
3566 - Floppy Disk Support:
3567 CONFIG_SYS_FDC_DRIVE_NUMBER
3569 the default drive number (default value 0)
3571 CONFIG_SYS_ISA_IO_STRIDE
3573 defines the spacing between FDC chipset registers
3576 CONFIG_SYS_ISA_IO_OFFSET
3578 defines the offset of register from address. It
3579 depends on which part of the data bus is connected to
3580 the FDC chipset. (default value 0)
3582 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3583 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3586 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3587 fdc_hw_init() is called at the beginning of the FDC
3588 setup. fdc_hw_init() must be provided by the board
3589 source code. It is used to make hardware dependant
3593 Most IDE controllers were designed to be connected with PCI
3594 interface. Only few of them were designed for AHB interface.
3595 When software is doing ATA command and data transfer to
3596 IDE devices through IDE-AHB controller, some additional
3597 registers accessing to these kind of IDE-AHB controller
3600 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3601 DO NOT CHANGE unless you know exactly what you're
3602 doing! (11-4) [MPC8xx/82xx systems only]
3604 - CONFIG_SYS_INIT_RAM_ADDR:
3606 Start address of memory area that can be used for
3607 initial data and stack; please note that this must be
3608 writable memory that is working WITHOUT special
3609 initialization, i. e. you CANNOT use normal RAM which
3610 will become available only after programming the
3611 memory controller and running certain initialization
3614 U-Boot uses the following memory types:
3615 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3616 - MPC824X: data cache
3617 - PPC4xx: data cache
3619 - CONFIG_SYS_GBL_DATA_OFFSET:
3621 Offset of the initial data structure in the memory
3622 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3623 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3624 data is located at the end of the available space
3625 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3626 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3627 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3628 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3631 On the MPC824X (or other systems that use the data
3632 cache for initial memory) the address chosen for
3633 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3634 point to an otherwise UNUSED address space between
3635 the top of RAM and the start of the PCI space.
3637 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3639 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3641 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3643 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3645 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3647 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3649 - CONFIG_SYS_OR_TIMING_SDRAM:
3652 - CONFIG_SYS_MAMR_PTA:
3653 periodic timer for refresh
3655 - CONFIG_SYS_DER: Debug Event Register (37-47)
3657 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3658 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3659 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3660 CONFIG_SYS_BR1_PRELIM:
3661 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3663 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3664 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3665 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3666 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3668 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3669 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3670 Machine Mode Register and Memory Periodic Timer
3671 Prescaler definitions (SDRAM timing)
3673 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3674 enable I2C microcode relocation patch (MPC8xx);
3675 define relocation offset in DPRAM [DSP2]
3677 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3678 enable SMC microcode relocation patch (MPC8xx);
3679 define relocation offset in DPRAM [SMC1]
3681 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3682 enable SPI microcode relocation patch (MPC8xx);
3683 define relocation offset in DPRAM [SCC4]
3685 - CONFIG_SYS_USE_OSCCLK:
3686 Use OSCM clock mode on MBX8xx board. Be careful,
3687 wrong setting might damage your board. Read
3688 doc/README.MBX before setting this variable!
3690 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3691 Offset of the bootmode word in DPRAM used by post
3692 (Power On Self Tests). This definition overrides
3693 #define'd default value in commproc.h resp.
3696 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3697 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3698 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3699 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3700 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3701 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3702 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3703 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3704 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3706 - CONFIG_PCI_DISABLE_PCIE:
3707 Disable PCI-Express on systems where it is supported but not
3710 - CONFIG_PCI_ENUM_ONLY
3711 Only scan through and get the devices on the busses.
3712 Don't do any setup work, presumably because someone or
3713 something has already done it, and we don't need to do it
3714 a second time. Useful for platforms that are pre-booted
3715 by coreboot or similar.
3718 Chip has SRIO or not
3721 Board has SRIO 1 port available
3724 Board has SRIO 2 port available
3726 - CONFIG_SYS_SRIOn_MEM_VIRT:
3727 Virtual Address of SRIO port 'n' memory region
3729 - CONFIG_SYS_SRIOn_MEM_PHYS:
3730 Physical Address of SRIO port 'n' memory region
3732 - CONFIG_SYS_SRIOn_MEM_SIZE:
3733 Size of SRIO port 'n' memory region
3735 - CONFIG_SYS_NDFC_16
3736 Defined to tell the NDFC that the NAND chip is using a
3739 - CONFIG_SYS_NDFC_EBC0_CFG
3740 Sets the EBC0_CFG register for the NDFC. If not defined
3741 a default value will be used.
3744 Get DDR timing information from an I2C EEPROM. Common
3745 with pluggable memory modules such as SODIMMs
3748 I2C address of the SPD EEPROM
3750 - CONFIG_SYS_SPD_BUS_NUM
3751 If SPD EEPROM is on an I2C bus other than the first
3752 one, specify here. Note that the value must resolve
3753 to something your driver can deal with.
3755 - CONFIG_SYS_DDR_RAW_TIMING
3756 Get DDR timing information from other than SPD. Common with
3757 soldered DDR chips onboard without SPD. DDR raw timing
3758 parameters are extracted from datasheet and hard-coded into
3759 header files or board specific files.
3761 - CONFIG_FSL_DDR_INTERACTIVE
3762 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3764 - CONFIG_SYS_83XX_DDR_USES_CS0
3765 Only for 83xx systems. If specified, then DDR should
3766 be configured using CS0 and CS1 instead of CS2 and CS3.
3768 - CONFIG_ETHER_ON_FEC[12]
3769 Define to enable FEC[12] on a 8xx series processor.
3771 - CONFIG_FEC[12]_PHY
3772 Define to the hardcoded PHY address which corresponds
3773 to the given FEC; i. e.
3774 #define CONFIG_FEC1_PHY 4
3775 means that the PHY with address 4 is connected to FEC1
3777 When set to -1, means to probe for first available.
3779 - CONFIG_FEC[12]_PHY_NORXERR
3780 The PHY does not have a RXERR line (RMII only).
3781 (so program the FEC to ignore it).
3784 Enable RMII mode for all FECs.
3785 Note that this is a global option, we can't
3786 have one FEC in standard MII mode and another in RMII mode.
3788 - CONFIG_CRC32_VERIFY
3789 Add a verify option to the crc32 command.
3792 => crc32 -v <address> <count> <crc32>
3794 Where address/count indicate a memory area
3795 and crc32 is the correct crc32 which the
3799 Add the "loopw" memory command. This only takes effect if
3800 the memory commands are activated globally (CONFIG_CMD_MEM).
3803 Add the "mdc" and "mwc" memory commands. These are cyclic
3808 This command will print 4 bytes (10,11,12,13) each 500 ms.
3810 => mwc.l 100 12345678 10
3811 This command will write 12345678 to address 100 all 10 ms.
3813 This only takes effect if the memory commands are activated
3814 globally (CONFIG_CMD_MEM).
3816 - CONFIG_SKIP_LOWLEVEL_INIT
3817 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3818 low level initializations (like setting up the memory
3819 controller) are omitted and/or U-Boot does not
3820 relocate itself into RAM.
3822 Normally this variable MUST NOT be defined. The only
3823 exception is when U-Boot is loaded (to RAM) by some
3824 other boot loader or by a debugger which performs
3825 these initializations itself.
3828 Modifies the behaviour of start.S when compiling a loader
3829 that is executed before the actual U-Boot. E.g. when
3830 compiling a NAND SPL.
3832 - CONFIG_USE_ARCH_MEMCPY
3833 CONFIG_USE_ARCH_MEMSET
3834 If these options are used a optimized version of memcpy/memset will
3835 be used if available. These functions may be faster under some
3836 conditions but may increase the binary size.
3838 - CONFIG_X86_RESET_VECTOR
3839 If defined, the x86 reset vector code is included. This is not
3840 needed when U-Boot is running from Coreboot.
3843 Freescale QE/FMAN Firmware Support:
3844 -----------------------------------
3846 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3847 loading of "firmware", which is encoded in the QE firmware binary format.
3848 This firmware often needs to be loaded during U-Boot booting, so macros
3849 are used to identify the storage device (NOR flash, SPI, etc) and the address
3852 - CONFIG_SYS_QE_FMAN_FW_ADDR
3853 The address in the storage device where the firmware is located. The
3854 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3857 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3858 The maximum possible size of the firmware. The firmware binary format
3859 has a field that specifies the actual size of the firmware, but it
3860 might not be possible to read any part of the firmware unless some
3861 local storage is allocated to hold the entire firmware first.
3863 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3864 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3865 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3866 virtual address in NOR flash.
3868 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3869 Specifies that QE/FMAN firmware is located in NAND flash.
3870 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3872 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3873 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3874 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3876 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3877 Specifies that QE/FMAN firmware is located on the primary SPI
3878 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3880 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3881 Specifies that QE/FMAN firmware is located in the remote (master)
3882 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3883 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3884 window->master inbound window->master LAW->the ucode address in
3885 master's memory space.
3887 Building the Software:
3888 ======================
3890 Building U-Boot has been tested in several native build environments
3891 and in many different cross environments. Of course we cannot support
3892 all possibly existing versions of cross development tools in all
3893 (potentially obsolete) versions. In case of tool chain problems we
3894 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3895 which is extensively used to build and test U-Boot.
3897 If you are not using a native environment, it is assumed that you
3898 have GNU cross compiling tools available in your path. In this case,
3899 you must set the environment variable CROSS_COMPILE in your shell.
3900 Note that no changes to the Makefile or any other source files are
3901 necessary. For example using the ELDK on a 4xx CPU, please enter:
3903 $ CROSS_COMPILE=ppc_4xx-
3904 $ export CROSS_COMPILE
3906 Note: If you wish to generate Windows versions of the utilities in
3907 the tools directory you can use the MinGW toolchain
3908 (http://www.mingw.org). Set your HOST tools to the MinGW
3909 toolchain and execute 'make tools'. For example:
3911 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3913 Binaries such as tools/mkimage.exe will be created which can
3914 be executed on computers running Windows.
3916 U-Boot is intended to be simple to build. After installing the
3917 sources you must configure U-Boot for one specific board type. This
3922 where "NAME_config" is the name of one of the existing configu-
3923 rations; see boards.cfg for supported names.
3925 Note: for some board special configuration names may exist; check if
3926 additional information is available from the board vendor; for
3927 instance, the TQM823L systems are available without (standard)
3928 or with LCD support. You can select such additional "features"
3929 when choosing the configuration, i. e.
3932 - will configure for a plain TQM823L, i. e. no LCD support
3934 make TQM823L_LCD_config
3935 - will configure for a TQM823L with U-Boot console on LCD
3940 Finally, type "make all", and you should get some working U-Boot
3941 images ready for download to / installation on your system:
3943 - "u-boot.bin" is a raw binary image
3944 - "u-boot" is an image in ELF binary format
3945 - "u-boot.srec" is in Motorola S-Record format
3947 By default the build is performed locally and the objects are saved
3948 in the source directory. One of the two methods can be used to change
3949 this behavior and build U-Boot to some external directory:
3951 1. Add O= to the make command line invocations:
3953 make O=/tmp/build distclean
3954 make O=/tmp/build NAME_config
3955 make O=/tmp/build all
3957 2. Set environment variable BUILD_DIR to point to the desired location:
3959 export BUILD_DIR=/tmp/build
3964 Note that the command line "O=" setting overrides the BUILD_DIR environment
3968 Please be aware that the Makefiles assume you are using GNU make, so
3969 for instance on NetBSD you might need to use "gmake" instead of
3973 If the system board that you have is not listed, then you will need
3974 to port U-Boot to your hardware platform. To do this, follow these
3977 1. Add a new configuration option for your board to the toplevel
3978 "boards.cfg" file, using the existing entries as examples.
3979 Follow the instructions there to keep the boards in order.
3980 2. Create a new directory to hold your board specific code. Add any
3981 files you need. In your board directory, you will need at least
3982 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3983 3. Create a new configuration file "include/configs/<board>.h" for
3985 3. If you're porting U-Boot to a new CPU, then also create a new
3986 directory to hold your CPU specific code. Add any files you need.
3987 4. Run "make <board>_config" with your new name.
3988 5. Type "make", and you should get a working "u-boot.srec" file
3989 to be installed on your target system.
3990 6. Debug and solve any problems that might arise.
3991 [Of course, this last step is much harder than it sounds.]
3994 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3995 ==============================================================
3997 If you have modified U-Boot sources (for instance added a new board
3998 or support for new devices, a new CPU, etc.) you are expected to
3999 provide feedback to the other developers. The feedback normally takes
4000 the form of a "patch", i. e. a context diff against a certain (latest
4001 official or latest in the git repository) version of U-Boot sources.
4003 But before you submit such a patch, please verify that your modifi-
4004 cation did not break existing code. At least make sure that *ALL* of
4005 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4006 just run the "MAKEALL" script, which will configure and build U-Boot
4007 for ALL supported system. Be warned, this will take a while. You can
4008 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4009 environment variable to the script, i. e. to use the ELDK cross tools
4012 CROSS_COMPILE=ppc_8xx- MAKEALL
4014 or to build on a native PowerPC system you can type
4016 CROSS_COMPILE=' ' MAKEALL
4018 When using the MAKEALL script, the default behaviour is to build
4019 U-Boot in the source directory. This location can be changed by
4020 setting the BUILD_DIR environment variable. Also, for each target
4021 built, the MAKEALL script saves two log files (<target>.ERR and
4022 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4023 location can be changed by setting the MAKEALL_LOGDIR environment
4024 variable. For example:
4026 export BUILD_DIR=/tmp/build
4027 export MAKEALL_LOGDIR=/tmp/log
4028 CROSS_COMPILE=ppc_8xx- MAKEALL
4030 With the above settings build objects are saved in the /tmp/build,
4031 log files are saved in the /tmp/log and the source tree remains clean
4032 during the whole build process.
4035 See also "U-Boot Porting Guide" below.
4038 Monitor Commands - Overview:
4039 ============================
4041 go - start application at address 'addr'
4042 run - run commands in an environment variable
4043 bootm - boot application image from memory
4044 bootp - boot image via network using BootP/TFTP protocol
4045 bootz - boot zImage from memory
4046 tftpboot- boot image via network using TFTP protocol
4047 and env variables "ipaddr" and "serverip"
4048 (and eventually "gatewayip")
4049 tftpput - upload a file via network using TFTP protocol
4050 rarpboot- boot image via network using RARP/TFTP protocol
4051 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4052 loads - load S-Record file over serial line
4053 loadb - load binary file over serial line (kermit mode)
4055 mm - memory modify (auto-incrementing)
4056 nm - memory modify (constant address)
4057 mw - memory write (fill)
4059 cmp - memory compare
4060 crc32 - checksum calculation
4061 i2c - I2C sub-system
4062 sspi - SPI utility commands
4063 base - print or set address offset
4064 printenv- print environment variables
4065 setenv - set environment variables
4066 saveenv - save environment variables to persistent storage
4067 protect - enable or disable FLASH write protection
4068 erase - erase FLASH memory
4069 flinfo - print FLASH memory information
4070 nand - NAND memory operations (see doc/README.nand)
4071 bdinfo - print Board Info structure
4072 iminfo - print header information for application image
4073 coninfo - print console devices and informations
4074 ide - IDE sub-system
4075 loop - infinite loop on address range
4076 loopw - infinite write loop on address range
4077 mtest - simple RAM test
4078 icache - enable or disable instruction cache
4079 dcache - enable or disable data cache
4080 reset - Perform RESET of the CPU
4081 echo - echo args to console
4082 version - print monitor version
4083 help - print online help
4084 ? - alias for 'help'
4087 Monitor Commands - Detailed Description:
4088 ========================================
4092 For now: just type "help <command>".
4095 Environment Variables:
4096 ======================
4098 U-Boot supports user configuration using Environment Variables which
4099 can be made persistent by saving to Flash memory.
4101 Environment Variables are set using "setenv", printed using
4102 "printenv", and saved to Flash using "saveenv". Using "setenv"
4103 without a value can be used to delete a variable from the
4104 environment. As long as you don't save the environment you are
4105 working with an in-memory copy. In case the Flash area containing the
4106 environment is erased by accident, a default environment is provided.
4108 Some configuration options can be set using Environment Variables.
4110 List of environment variables (most likely not complete):
4112 baudrate - see CONFIG_BAUDRATE
4114 bootdelay - see CONFIG_BOOTDELAY
4116 bootcmd - see CONFIG_BOOTCOMMAND
4118 bootargs - Boot arguments when booting an RTOS image
4120 bootfile - Name of the image to load with TFTP
4122 bootm_low - Memory range available for image processing in the bootm
4123 command can be restricted. This variable is given as
4124 a hexadecimal number and defines lowest address allowed
4125 for use by the bootm command. See also "bootm_size"
4126 environment variable. Address defined by "bootm_low" is
4127 also the base of the initial memory mapping for the Linux
4128 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4131 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4132 This variable is given as a hexadecimal number and it
4133 defines the size of the memory region starting at base
4134 address bootm_low that is accessible by the Linux kernel
4135 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4136 as the default value if it is defined, and bootm_size is
4139 bootm_size - Memory range available for image processing in the bootm
4140 command can be restricted. This variable is given as
4141 a hexadecimal number and defines the size of the region
4142 allowed for use by the bootm command. See also "bootm_low"
4143 environment variable.
4145 updatefile - Location of the software update file on a TFTP server, used
4146 by the automatic software update feature. Please refer to
4147 documentation in doc/README.update for more details.
4149 autoload - if set to "no" (any string beginning with 'n'),
4150 "bootp" will just load perform a lookup of the
4151 configuration from the BOOTP server, but not try to
4152 load any image using TFTP
4154 autostart - if set to "yes", an image loaded using the "bootp",
4155 "rarpboot", "tftpboot" or "diskboot" commands will
4156 be automatically started (by internally calling
4159 If set to "no", a standalone image passed to the
4160 "bootm" command will be copied to the load address
4161 (and eventually uncompressed), but NOT be started.
4162 This can be used to load and uncompress arbitrary
4165 fdt_high - if set this restricts the maximum address that the
4166 flattened device tree will be copied into upon boot.
4167 For example, if you have a system with 1 GB memory
4168 at physical address 0x10000000, while Linux kernel
4169 only recognizes the first 704 MB as low memory, you
4170 may need to set fdt_high as 0x3C000000 to have the
4171 device tree blob be copied to the maximum address
4172 of the 704 MB low memory, so that Linux kernel can
4173 access it during the boot procedure.
4175 If this is set to the special value 0xFFFFFFFF then
4176 the fdt will not be copied at all on boot. For this
4177 to work it must reside in writable memory, have
4178 sufficient padding on the end of it for u-boot to
4179 add the information it needs into it, and the memory
4180 must be accessible by the kernel.
4182 fdtcontroladdr- if set this is the address of the control flattened
4183 device tree used by U-Boot when CONFIG_OF_CONTROL is
4186 i2cfast - (PPC405GP|PPC405EP only)
4187 if set to 'y' configures Linux I2C driver for fast
4188 mode (400kHZ). This environment variable is used in
4189 initialization code. So, for changes to be effective
4190 it must be saved and board must be reset.
4192 initrd_high - restrict positioning of initrd images:
4193 If this variable is not set, initrd images will be
4194 copied to the highest possible address in RAM; this
4195 is usually what you want since it allows for
4196 maximum initrd size. If for some reason you want to
4197 make sure that the initrd image is loaded below the
4198 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4199 variable to a value of "no" or "off" or "0".
4200 Alternatively, you can set it to a maximum upper
4201 address to use (U-Boot will still check that it
4202 does not overwrite the U-Boot stack and data).
4204 For instance, when you have a system with 16 MB
4205 RAM, and want to reserve 4 MB from use by Linux,
4206 you can do this by adding "mem=12M" to the value of
4207 the "bootargs" variable. However, now you must make
4208 sure that the initrd image is placed in the first
4209 12 MB as well - this can be done with
4211 setenv initrd_high 00c00000
4213 If you set initrd_high to 0xFFFFFFFF, this is an
4214 indication to U-Boot that all addresses are legal
4215 for the Linux kernel, including addresses in flash
4216 memory. In this case U-Boot will NOT COPY the
4217 ramdisk at all. This may be useful to reduce the
4218 boot time on your system, but requires that this
4219 feature is supported by your Linux kernel.
4221 ipaddr - IP address; needed for tftpboot command
4223 loadaddr - Default load address for commands like "bootp",
4224 "rarpboot", "tftpboot", "loadb" or "diskboot"
4226 loads_echo - see CONFIG_LOADS_ECHO
4228 serverip - TFTP server IP address; needed for tftpboot command
4230 bootretry - see CONFIG_BOOT_RETRY_TIME
4232 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4234 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4236 ethprime - controls which interface is used first.
4238 ethact - controls which interface is currently active.
4239 For example you can do the following
4241 => setenv ethact FEC
4242 => ping 192.168.0.1 # traffic sent on FEC
4243 => setenv ethact SCC
4244 => ping 10.0.0.1 # traffic sent on SCC
4246 ethrotate - When set to "no" U-Boot does not go through all
4247 available network interfaces.
4248 It just stays at the currently selected interface.
4250 netretry - When set to "no" each network operation will
4251 either succeed or fail without retrying.
4252 When set to "once" the network operation will
4253 fail when all the available network interfaces
4254 are tried once without success.
4255 Useful on scripts which control the retry operation
4258 npe_ucode - set load address for the NPE microcode
4260 tftpsrcport - If this is set, the value is used for TFTP's
4263 tftpdstport - If this is set, the value is used for TFTP's UDP
4264 destination port instead of the Well Know Port 69.
4266 tftpblocksize - Block size to use for TFTP transfers; if not set,
4267 we use the TFTP server's default block size
4269 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4270 seconds, minimum value is 1000 = 1 second). Defines
4271 when a packet is considered to be lost so it has to
4272 be retransmitted. The default is 5000 = 5 seconds.
4273 Lowering this value may make downloads succeed
4274 faster in networks with high packet loss rates or
4275 with unreliable TFTP servers.
4277 vlan - When set to a value < 4095 the traffic over
4278 Ethernet is encapsulated/received over 802.1q
4281 The following image location variables contain the location of images
4282 used in booting. The "Image" column gives the role of the image and is
4283 not an environment variable name. The other columns are environment
4284 variable names. "File Name" gives the name of the file on a TFTP
4285 server, "RAM Address" gives the location in RAM the image will be
4286 loaded to, and "Flash Location" gives the image's address in NOR
4287 flash or offset in NAND flash.
4289 *Note* - these variables don't have to be defined for all boards, some
4290 boards currenlty use other variables for these purposes, and some
4291 boards use these variables for other purposes.
4293 Image File Name RAM Address Flash Location
4294 ----- --------- ----------- --------------
4295 u-boot u-boot u-boot_addr_r u-boot_addr
4296 Linux kernel bootfile kernel_addr_r kernel_addr
4297 device tree blob fdtfile fdt_addr_r fdt_addr
4298 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4300 The following environment variables may be used and automatically
4301 updated by the network boot commands ("bootp" and "rarpboot"),
4302 depending the information provided by your boot server:
4304 bootfile - see above
4305 dnsip - IP address of your Domain Name Server
4306 dnsip2 - IP address of your secondary Domain Name Server
4307 gatewayip - IP address of the Gateway (Router) to use
4308 hostname - Target hostname
4310 netmask - Subnet Mask
4311 rootpath - Pathname of the root filesystem on the NFS server
4312 serverip - see above
4315 There are two special Environment Variables:
4317 serial# - contains hardware identification information such
4318 as type string and/or serial number
4319 ethaddr - Ethernet address
4321 These variables can be set only once (usually during manufacturing of
4322 the board). U-Boot refuses to delete or overwrite these variables
4323 once they have been set once.
4326 Further special Environment Variables:
4328 ver - Contains the U-Boot version string as printed
4329 with the "version" command. This variable is
4330 readonly (see CONFIG_VERSION_VARIABLE).
4333 Please note that changes to some configuration parameters may take
4334 only effect after the next boot (yes, that's just like Windoze :-).
4337 Callback functions for environment variables:
4338 ---------------------------------------------
4340 For some environment variables, the behavior of u-boot needs to change
4341 when their values are changed. This functionailty allows functions to
4342 be associated with arbitrary variables. On creation, overwrite, or
4343 deletion, the callback will provide the opportunity for some side
4344 effect to happen or for the change to be rejected.
4346 The callbacks are named and associated with a function using the
4347 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4349 These callbacks are associated with variables in one of two ways. The
4350 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4351 in the board configuration to a string that defines a list of
4352 associations. The list must be in the following format:
4354 entry = variable_name[:callback_name]
4357 If the callback name is not specified, then the callback is deleted.
4358 Spaces are also allowed anywhere in the list.
4360 Callbacks can also be associated by defining the ".callbacks" variable
4361 with the same list format above. Any association in ".callbacks" will
4362 override any association in the static list. You can define
4363 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4364 ".callbacks" envirnoment variable in the default or embedded environment.
4367 Command Line Parsing:
4368 =====================
4370 There are two different command line parsers available with U-Boot:
4371 the old "simple" one, and the much more powerful "hush" shell:
4373 Old, simple command line parser:
4374 --------------------------------
4376 - supports environment variables (through setenv / saveenv commands)
4377 - several commands on one line, separated by ';'
4378 - variable substitution using "... ${name} ..." syntax
4379 - special characters ('$', ';') can be escaped by prefixing with '\',
4381 setenv bootcmd bootm \${address}
4382 - You can also escape text by enclosing in single apostrophes, for example:
4383 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4388 - similar to Bourne shell, with control structures like
4389 if...then...else...fi, for...do...done; while...do...done,
4390 until...do...done, ...
4391 - supports environment ("global") variables (through setenv / saveenv
4392 commands) and local shell variables (through standard shell syntax
4393 "name=value"); only environment variables can be used with "run"
4399 (1) If a command line (or an environment variable executed by a "run"
4400 command) contains several commands separated by semicolon, and
4401 one of these commands fails, then the remaining commands will be
4404 (2) If you execute several variables with one call to run (i. e.
4405 calling run with a list of variables as arguments), any failing
4406 command will cause "run" to terminate, i. e. the remaining
4407 variables are not executed.
4409 Note for Redundant Ethernet Interfaces:
4410 =======================================
4412 Some boards come with redundant Ethernet interfaces; U-Boot supports
4413 such configurations and is capable of automatic selection of a
4414 "working" interface when needed. MAC assignment works as follows:
4416 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4417 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4418 "eth1addr" (=>eth1), "eth2addr", ...
4420 If the network interface stores some valid MAC address (for instance
4421 in SROM), this is used as default address if there is NO correspon-
4422 ding setting in the environment; if the corresponding environment
4423 variable is set, this overrides the settings in the card; that means:
4425 o If the SROM has a valid MAC address, and there is no address in the
4426 environment, the SROM's address is used.
4428 o If there is no valid address in the SROM, and a definition in the
4429 environment exists, then the value from the environment variable is
4432 o If both the SROM and the environment contain a MAC address, and
4433 both addresses are the same, this MAC address is used.
4435 o If both the SROM and the environment contain a MAC address, and the
4436 addresses differ, the value from the environment is used and a
4439 o If neither SROM nor the environment contain a MAC address, an error
4442 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4443 will be programmed into hardware as part of the initialization process. This
4444 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4445 The naming convention is as follows:
4446 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4451 U-Boot is capable of booting (and performing other auxiliary operations on)
4452 images in two formats:
4454 New uImage format (FIT)
4455 -----------------------
4457 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4458 to Flattened Device Tree). It allows the use of images with multiple
4459 components (several kernels, ramdisks, etc.), with contents protected by
4460 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4466 Old image format is based on binary files which can be basically anything,
4467 preceded by a special header; see the definitions in include/image.h for
4468 details; basically, the header defines the following image properties:
4470 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4471 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4472 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4473 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4475 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4476 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4477 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4478 * Compression Type (uncompressed, gzip, bzip2)
4484 The header is marked by a special Magic Number, and both the header
4485 and the data portions of the image are secured against corruption by
4492 Although U-Boot should support any OS or standalone application
4493 easily, the main focus has always been on Linux during the design of
4496 U-Boot includes many features that so far have been part of some
4497 special "boot loader" code within the Linux kernel. Also, any
4498 "initrd" images to be used are no longer part of one big Linux image;
4499 instead, kernel and "initrd" are separate images. This implementation
4500 serves several purposes:
4502 - the same features can be used for other OS or standalone
4503 applications (for instance: using compressed images to reduce the
4504 Flash memory footprint)
4506 - it becomes much easier to port new Linux kernel versions because
4507 lots of low-level, hardware dependent stuff are done by U-Boot
4509 - the same Linux kernel image can now be used with different "initrd"
4510 images; of course this also means that different kernel images can
4511 be run with the same "initrd". This makes testing easier (you don't
4512 have to build a new "zImage.initrd" Linux image when you just
4513 change a file in your "initrd"). Also, a field-upgrade of the
4514 software is easier now.
4520 Porting Linux to U-Boot based systems:
4521 ---------------------------------------
4523 U-Boot cannot save you from doing all the necessary modifications to
4524 configure the Linux device drivers for use with your target hardware
4525 (no, we don't intend to provide a full virtual machine interface to
4528 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4530 Just make sure your machine specific header file (for instance
4531 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4532 Information structure as we define in include/asm-<arch>/u-boot.h,
4533 and make sure that your definition of IMAP_ADDR uses the same value
4534 as your U-Boot configuration in CONFIG_SYS_IMMR.
4537 Configuring the Linux kernel:
4538 -----------------------------
4540 No specific requirements for U-Boot. Make sure you have some root
4541 device (initial ramdisk, NFS) for your target system.
4544 Building a Linux Image:
4545 -----------------------
4547 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4548 not used. If you use recent kernel source, a new build target
4549 "uImage" will exist which automatically builds an image usable by
4550 U-Boot. Most older kernels also have support for a "pImage" target,
4551 which was introduced for our predecessor project PPCBoot and uses a
4552 100% compatible format.
4561 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4562 encapsulate a compressed Linux kernel image with header information,
4563 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4565 * build a standard "vmlinux" kernel image (in ELF binary format):
4567 * convert the kernel into a raw binary image:
4569 ${CROSS_COMPILE}-objcopy -O binary \
4570 -R .note -R .comment \
4571 -S vmlinux linux.bin
4573 * compress the binary image:
4577 * package compressed binary image for U-Boot:
4579 mkimage -A ppc -O linux -T kernel -C gzip \
4580 -a 0 -e 0 -n "Linux Kernel Image" \
4581 -d linux.bin.gz uImage
4584 The "mkimage" tool can also be used to create ramdisk images for use
4585 with U-Boot, either separated from the Linux kernel image, or
4586 combined into one file. "mkimage" encapsulates the images with a 64
4587 byte header containing information about target architecture,
4588 operating system, image type, compression method, entry points, time
4589 stamp, CRC32 checksums, etc.
4591 "mkimage" can be called in two ways: to verify existing images and
4592 print the header information, or to build new images.
4594 In the first form (with "-l" option) mkimage lists the information
4595 contained in the header of an existing U-Boot image; this includes
4596 checksum verification:
4598 tools/mkimage -l image
4599 -l ==> list image header information
4601 The second form (with "-d" option) is used to build a U-Boot image
4602 from a "data file" which is used as image payload:
4604 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4605 -n name -d data_file image
4606 -A ==> set architecture to 'arch'
4607 -O ==> set operating system to 'os'
4608 -T ==> set image type to 'type'
4609 -C ==> set compression type 'comp'
4610 -a ==> set load address to 'addr' (hex)
4611 -e ==> set entry point to 'ep' (hex)
4612 -n ==> set image name to 'name'
4613 -d ==> use image data from 'datafile'
4615 Right now, all Linux kernels for PowerPC systems use the same load
4616 address (0x00000000), but the entry point address depends on the
4619 - 2.2.x kernels have the entry point at 0x0000000C,
4620 - 2.3.x and later kernels have the entry point at 0x00000000.
4622 So a typical call to build a U-Boot image would read:
4624 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4625 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4626 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4627 > examples/uImage.TQM850L
4628 Image Name: 2.4.4 kernel for TQM850L
4629 Created: Wed Jul 19 02:34:59 2000
4630 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4631 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4632 Load Address: 0x00000000
4633 Entry Point: 0x00000000
4635 To verify the contents of the image (or check for corruption):
4637 -> tools/mkimage -l examples/uImage.TQM850L
4638 Image Name: 2.4.4 kernel for TQM850L
4639 Created: Wed Jul 19 02:34:59 2000
4640 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4641 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4642 Load Address: 0x00000000
4643 Entry Point: 0x00000000
4645 NOTE: for embedded systems where boot time is critical you can trade
4646 speed for memory and install an UNCOMPRESSED image instead: this
4647 needs more space in Flash, but boots much faster since it does not
4648 need to be uncompressed:
4650 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4651 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4652 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4653 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4654 > examples/uImage.TQM850L-uncompressed
4655 Image Name: 2.4.4 kernel for TQM850L
4656 Created: Wed Jul 19 02:34:59 2000
4657 Image Type: PowerPC Linux Kernel Image (uncompressed)
4658 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4659 Load Address: 0x00000000
4660 Entry Point: 0x00000000
4663 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4664 when your kernel is intended to use an initial ramdisk:
4666 -> tools/mkimage -n 'Simple Ramdisk Image' \
4667 > -A ppc -O linux -T ramdisk -C gzip \
4668 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4669 Image Name: Simple Ramdisk Image
4670 Created: Wed Jan 12 14:01:50 2000
4671 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4672 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4673 Load Address: 0x00000000
4674 Entry Point: 0x00000000
4677 Installing a Linux Image:
4678 -------------------------
4680 To downloading a U-Boot image over the serial (console) interface,
4681 you must convert the image to S-Record format:
4683 objcopy -I binary -O srec examples/image examples/image.srec
4685 The 'objcopy' does not understand the information in the U-Boot
4686 image header, so the resulting S-Record file will be relative to
4687 address 0x00000000. To load it to a given address, you need to
4688 specify the target address as 'offset' parameter with the 'loads'
4691 Example: install the image to address 0x40100000 (which on the
4692 TQM8xxL is in the first Flash bank):
4694 => erase 40100000 401FFFFF
4700 ## Ready for S-Record download ...
4701 ~>examples/image.srec
4702 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4704 15989 15990 15991 15992
4705 [file transfer complete]
4707 ## Start Addr = 0x00000000
4710 You can check the success of the download using the 'iminfo' command;
4711 this includes a checksum verification so you can be sure no data
4712 corruption happened:
4716 ## Checking Image at 40100000 ...
4717 Image Name: 2.2.13 for initrd on TQM850L
4718 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4719 Data Size: 335725 Bytes = 327 kB = 0 MB
4720 Load Address: 00000000
4721 Entry Point: 0000000c
4722 Verifying Checksum ... OK
4728 The "bootm" command is used to boot an application that is stored in
4729 memory (RAM or Flash). In case of a Linux kernel image, the contents
4730 of the "bootargs" environment variable is passed to the kernel as
4731 parameters. You can check and modify this variable using the
4732 "printenv" and "setenv" commands:
4735 => printenv bootargs
4736 bootargs=root=/dev/ram
4738 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4740 => printenv bootargs
4741 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4744 ## Booting Linux kernel at 40020000 ...
4745 Image Name: 2.2.13 for NFS on TQM850L
4746 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4747 Data Size: 381681 Bytes = 372 kB = 0 MB
4748 Load Address: 00000000
4749 Entry Point: 0000000c
4750 Verifying Checksum ... OK
4751 Uncompressing Kernel Image ... OK
4752 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
4753 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4754 time_init: decrementer frequency = 187500000/60
4755 Calibrating delay loop... 49.77 BogoMIPS
4756 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4759 If you want to boot a Linux kernel with initial RAM disk, you pass
4760 the memory addresses of both the kernel and the initrd image (PPBCOOT
4761 format!) to the "bootm" command:
4763 => imi 40100000 40200000
4765 ## Checking Image at 40100000 ...
4766 Image Name: 2.2.13 for initrd on TQM850L
4767 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4768 Data Size: 335725 Bytes = 327 kB = 0 MB
4769 Load Address: 00000000
4770 Entry Point: 0000000c
4771 Verifying Checksum ... OK
4773 ## Checking Image at 40200000 ...
4774 Image Name: Simple Ramdisk Image
4775 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4776 Data Size: 566530 Bytes = 553 kB = 0 MB
4777 Load Address: 00000000
4778 Entry Point: 00000000
4779 Verifying Checksum ... OK
4781 => bootm 40100000 40200000
4782 ## Booting Linux kernel at 40100000 ...
4783 Image Name: 2.2.13 for initrd on TQM850L
4784 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4785 Data Size: 335725 Bytes = 327 kB = 0 MB
4786 Load Address: 00000000
4787 Entry Point: 0000000c
4788 Verifying Checksum ... OK
4789 Uncompressing Kernel Image ... OK
4790 ## Loading RAMDisk Image at 40200000 ...
4791 Image Name: Simple Ramdisk Image
4792 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4793 Data Size: 566530 Bytes = 553 kB = 0 MB
4794 Load Address: 00000000
4795 Entry Point: 00000000
4796 Verifying Checksum ... OK
4797 Loading Ramdisk ... OK
4798 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
4799 Boot arguments: root=/dev/ram
4800 time_init: decrementer frequency = 187500000/60
4801 Calibrating delay loop... 49.77 BogoMIPS
4803 RAMDISK: Compressed image found at block 0
4804 VFS: Mounted root (ext2 filesystem).
4808 Boot Linux and pass a flat device tree:
4811 First, U-Boot must be compiled with the appropriate defines. See the section
4812 titled "Linux Kernel Interface" above for a more in depth explanation. The
4813 following is an example of how to start a kernel and pass an updated
4819 oft=oftrees/mpc8540ads.dtb
4820 => tftp $oftaddr $oft
4821 Speed: 1000, full duplex
4823 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4824 Filename 'oftrees/mpc8540ads.dtb'.
4825 Load address: 0x300000
4828 Bytes transferred = 4106 (100a hex)
4829 => tftp $loadaddr $bootfile
4830 Speed: 1000, full duplex
4832 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4834 Load address: 0x200000
4835 Loading:############
4837 Bytes transferred = 1029407 (fb51f hex)
4842 => bootm $loadaddr - $oftaddr
4843 ## Booting image at 00200000 ...
4844 Image Name: Linux-2.6.17-dirty
4845 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4846 Data Size: 1029343 Bytes = 1005.2 kB
4847 Load Address: 00000000
4848 Entry Point: 00000000
4849 Verifying Checksum ... OK
4850 Uncompressing Kernel Image ... OK
4851 Booting using flat device tree at 0x300000
4852 Using MPC85xx ADS machine description
4853 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4857 More About U-Boot Image Types:
4858 ------------------------------
4860 U-Boot supports the following image types:
4862 "Standalone Programs" are directly runnable in the environment
4863 provided by U-Boot; it is expected that (if they behave
4864 well) you can continue to work in U-Boot after return from
4865 the Standalone Program.
4866 "OS Kernel Images" are usually images of some Embedded OS which
4867 will take over control completely. Usually these programs
4868 will install their own set of exception handlers, device
4869 drivers, set up the MMU, etc. - this means, that you cannot
4870 expect to re-enter U-Boot except by resetting the CPU.
4871 "RAMDisk Images" are more or less just data blocks, and their
4872 parameters (address, size) are passed to an OS kernel that is
4874 "Multi-File Images" contain several images, typically an OS
4875 (Linux) kernel image and one or more data images like
4876 RAMDisks. This construct is useful for instance when you want
4877 to boot over the network using BOOTP etc., where the boot
4878 server provides just a single image file, but you want to get
4879 for instance an OS kernel and a RAMDisk image.
4881 "Multi-File Images" start with a list of image sizes, each
4882 image size (in bytes) specified by an "uint32_t" in network
4883 byte order. This list is terminated by an "(uint32_t)0".
4884 Immediately after the terminating 0 follow the images, one by
4885 one, all aligned on "uint32_t" boundaries (size rounded up to
4886 a multiple of 4 bytes).
4888 "Firmware Images" are binary images containing firmware (like
4889 U-Boot or FPGA images) which usually will be programmed to
4892 "Script files" are command sequences that will be executed by
4893 U-Boot's command interpreter; this feature is especially
4894 useful when you configure U-Boot to use a real shell (hush)
4895 as command interpreter.
4897 Booting the Linux zImage:
4898 -------------------------
4900 On some platforms, it's possible to boot Linux zImage. This is done
4901 using the "bootz" command. The syntax of "bootz" command is the same
4902 as the syntax of "bootm" command.
4904 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4905 kernel with raw initrd images. The syntax is slightly different, the
4906 address of the initrd must be augmented by it's size, in the following
4907 format: "<initrd addres>:<initrd size>".
4913 One of the features of U-Boot is that you can dynamically load and
4914 run "standalone" applications, which can use some resources of
4915 U-Boot like console I/O functions or interrupt services.
4917 Two simple examples are included with the sources:
4922 'examples/hello_world.c' contains a small "Hello World" Demo
4923 application; it is automatically compiled when you build U-Boot.
4924 It's configured to run at address 0x00040004, so you can play with it
4928 ## Ready for S-Record download ...
4929 ~>examples/hello_world.srec
4930 1 2 3 4 5 6 7 8 9 10 11 ...
4931 [file transfer complete]
4933 ## Start Addr = 0x00040004
4935 => go 40004 Hello World! This is a test.
4936 ## Starting application at 0x00040004 ...
4947 Hit any key to exit ...
4949 ## Application terminated, rc = 0x0
4951 Another example, which demonstrates how to register a CPM interrupt
4952 handler with the U-Boot code, can be found in 'examples/timer.c'.
4953 Here, a CPM timer is set up to generate an interrupt every second.
4954 The interrupt service routine is trivial, just printing a '.'
4955 character, but this is just a demo program. The application can be
4956 controlled by the following keys:
4958 ? - print current values og the CPM Timer registers
4959 b - enable interrupts and start timer
4960 e - stop timer and disable interrupts
4961 q - quit application
4964 ## Ready for S-Record download ...
4965 ~>examples/timer.srec
4966 1 2 3 4 5 6 7 8 9 10 11 ...
4967 [file transfer complete]
4969 ## Start Addr = 0x00040004
4972 ## Starting application at 0x00040004 ...
4975 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4978 [q, b, e, ?] Set interval 1000000 us
4981 [q, b, e, ?] ........
4982 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4985 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4988 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4991 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4993 [q, b, e, ?] ...Stopping timer
4995 [q, b, e, ?] ## Application terminated, rc = 0x0
5001 Over time, many people have reported problems when trying to use the
5002 "minicom" terminal emulation program for serial download. I (wd)
5003 consider minicom to be broken, and recommend not to use it. Under
5004 Unix, I recommend to use C-Kermit for general purpose use (and
5005 especially for kermit binary protocol download ("loadb" command), and
5006 use "cu" for S-Record download ("loads" command). See
5007 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5008 for help with kermit.
5011 Nevertheless, if you absolutely want to use it try adding this
5012 configuration to your "File transfer protocols" section:
5014 Name Program Name U/D FullScr IO-Red. Multi
5015 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5016 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5022 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5023 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5025 Building requires a cross environment; it is known to work on
5026 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5027 need gmake since the Makefiles are not compatible with BSD make).
5028 Note that the cross-powerpc package does not install include files;
5029 attempting to build U-Boot will fail because <machine/ansi.h> is
5030 missing. This file has to be installed and patched manually:
5032 # cd /usr/pkg/cross/powerpc-netbsd/include
5034 # ln -s powerpc machine
5035 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5036 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5038 Native builds *don't* work due to incompatibilities between native
5039 and U-Boot include files.
5041 Booting assumes that (the first part of) the image booted is a
5042 stage-2 loader which in turn loads and then invokes the kernel
5043 proper. Loader sources will eventually appear in the NetBSD source
5044 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5045 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5048 Implementation Internals:
5049 =========================
5051 The following is not intended to be a complete description of every
5052 implementation detail. However, it should help to understand the
5053 inner workings of U-Boot and make it easier to port it to custom
5057 Initial Stack, Global Data:
5058 ---------------------------
5060 The implementation of U-Boot is complicated by the fact that U-Boot
5061 starts running out of ROM (flash memory), usually without access to
5062 system RAM (because the memory controller is not initialized yet).
5063 This means that we don't have writable Data or BSS segments, and BSS
5064 is not initialized as zero. To be able to get a C environment working
5065 at all, we have to allocate at least a minimal stack. Implementation
5066 options for this are defined and restricted by the CPU used: Some CPU
5067 models provide on-chip memory (like the IMMR area on MPC8xx and
5068 MPC826x processors), on others (parts of) the data cache can be
5069 locked as (mis-) used as memory, etc.
5071 Chris Hallinan posted a good summary of these issues to the
5072 U-Boot mailing list:
5074 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5075 From: "Chris Hallinan" <clh@net1plus.com>
5076 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5079 Correct me if I'm wrong, folks, but the way I understand it
5080 is this: Using DCACHE as initial RAM for Stack, etc, does not
5081 require any physical RAM backing up the cache. The cleverness
5082 is that the cache is being used as a temporary supply of
5083 necessary storage before the SDRAM controller is setup. It's
5084 beyond the scope of this list to explain the details, but you
5085 can see how this works by studying the cache architecture and
5086 operation in the architecture and processor-specific manuals.
5088 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5089 is another option for the system designer to use as an
5090 initial stack/RAM area prior to SDRAM being available. Either
5091 option should work for you. Using CS 4 should be fine if your
5092 board designers haven't used it for something that would
5093 cause you grief during the initial boot! It is frequently not
5096 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5097 with your processor/board/system design. The default value
5098 you will find in any recent u-boot distribution in
5099 walnut.h should work for you. I'd set it to a value larger
5100 than your SDRAM module. If you have a 64MB SDRAM module, set
5101 it above 400_0000. Just make sure your board has no resources
5102 that are supposed to respond to that address! That code in
5103 start.S has been around a while and should work as is when
5104 you get the config right.
5109 It is essential to remember this, since it has some impact on the C
5110 code for the initialization procedures:
5112 * Initialized global data (data segment) is read-only. Do not attempt
5115 * Do not use any uninitialized global data (or implicitely initialized
5116 as zero data - BSS segment) at all - this is undefined, initiali-
5117 zation is performed later (when relocating to RAM).
5119 * Stack space is very limited. Avoid big data buffers or things like
5122 Having only the stack as writable memory limits means we cannot use
5123 normal global data to share information beween the code. But it
5124 turned out that the implementation of U-Boot can be greatly
5125 simplified by making a global data structure (gd_t) available to all
5126 functions. We could pass a pointer to this data as argument to _all_
5127 functions, but this would bloat the code. Instead we use a feature of
5128 the GCC compiler (Global Register Variables) to share the data: we
5129 place a pointer (gd) to the global data into a register which we
5130 reserve for this purpose.
5132 When choosing a register for such a purpose we are restricted by the
5133 relevant (E)ABI specifications for the current architecture, and by
5134 GCC's implementation.
5136 For PowerPC, the following registers have specific use:
5138 R2: reserved for system use
5139 R3-R4: parameter passing and return values
5140 R5-R10: parameter passing
5141 R13: small data area pointer
5145 (U-Boot also uses R12 as internal GOT pointer. r12
5146 is a volatile register so r12 needs to be reset when
5147 going back and forth between asm and C)
5149 ==> U-Boot will use R2 to hold a pointer to the global data
5151 Note: on PPC, we could use a static initializer (since the
5152 address of the global data structure is known at compile time),
5153 but it turned out that reserving a register results in somewhat
5154 smaller code - although the code savings are not that big (on
5155 average for all boards 752 bytes for the whole U-Boot image,
5156 624 text + 127 data).
5158 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5159 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5161 ==> U-Boot will use P3 to hold a pointer to the global data
5163 On ARM, the following registers are used:
5165 R0: function argument word/integer result
5166 R1-R3: function argument word
5168 R10: stack limit (used only if stack checking if enabled)
5169 R11: argument (frame) pointer
5170 R12: temporary workspace
5173 R15: program counter
5175 ==> U-Boot will use R8 to hold a pointer to the global data
5177 On Nios II, the ABI is documented here:
5178 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5180 ==> U-Boot will use gp to hold a pointer to the global data
5182 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5183 to access small data sections, so gp is free.
5185 On NDS32, the following registers are used:
5187 R0-R1: argument/return
5189 R15: temporary register for assembler
5190 R16: trampoline register
5191 R28: frame pointer (FP)
5192 R29: global pointer (GP)
5193 R30: link register (LP)
5194 R31: stack pointer (SP)
5195 PC: program counter (PC)
5197 ==> U-Boot will use R10 to hold a pointer to the global data
5199 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5200 or current versions of GCC may "optimize" the code too much.
5205 U-Boot runs in system state and uses physical addresses, i.e. the
5206 MMU is not used either for address mapping nor for memory protection.
5208 The available memory is mapped to fixed addresses using the memory
5209 controller. In this process, a contiguous block is formed for each
5210 memory type (Flash, SDRAM, SRAM), even when it consists of several
5211 physical memory banks.
5213 U-Boot is installed in the first 128 kB of the first Flash bank (on
5214 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5215 booting and sizing and initializing DRAM, the code relocates itself
5216 to the upper end of DRAM. Immediately below the U-Boot code some
5217 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5218 configuration setting]. Below that, a structure with global Board
5219 Info data is placed, followed by the stack (growing downward).
5221 Additionally, some exception handler code is copied to the low 8 kB
5222 of DRAM (0x00000000 ... 0x00001FFF).
5224 So a typical memory configuration with 16 MB of DRAM could look like
5227 0x0000 0000 Exception Vector code
5230 0x0000 2000 Free for Application Use
5236 0x00FB FF20 Monitor Stack (Growing downward)
5237 0x00FB FFAC Board Info Data and permanent copy of global data
5238 0x00FC 0000 Malloc Arena
5241 0x00FE 0000 RAM Copy of Monitor Code
5242 ... eventually: LCD or video framebuffer
5243 ... eventually: pRAM (Protected RAM - unchanged by reset)
5244 0x00FF FFFF [End of RAM]
5247 System Initialization:
5248 ----------------------
5250 In the reset configuration, U-Boot starts at the reset entry point
5251 (on most PowerPC systems at address 0x00000100). Because of the reset
5252 configuration for CS0# this is a mirror of the onboard Flash memory.
5253 To be able to re-map memory U-Boot then jumps to its link address.
5254 To be able to implement the initialization code in C, a (small!)
5255 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5256 which provide such a feature like MPC8xx or MPC8260), or in a locked
5257 part of the data cache. After that, U-Boot initializes the CPU core,
5258 the caches and the SIU.
5260 Next, all (potentially) available memory banks are mapped using a
5261 preliminary mapping. For example, we put them on 512 MB boundaries
5262 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5263 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5264 programmed for SDRAM access. Using the temporary configuration, a
5265 simple memory test is run that determines the size of the SDRAM
5268 When there is more than one SDRAM bank, and the banks are of
5269 different size, the largest is mapped first. For equal size, the first
5270 bank (CS2#) is mapped first. The first mapping is always for address
5271 0x00000000, with any additional banks following immediately to create
5272 contiguous memory starting from 0.
5274 Then, the monitor installs itself at the upper end of the SDRAM area
5275 and allocates memory for use by malloc() and for the global Board
5276 Info data; also, the exception vector code is copied to the low RAM
5277 pages, and the final stack is set up.
5279 Only after this relocation will you have a "normal" C environment;
5280 until that you are restricted in several ways, mostly because you are
5281 running from ROM, and because the code will have to be relocated to a
5285 U-Boot Porting Guide:
5286 ----------------------
5288 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5292 int main(int argc, char *argv[])
5294 sighandler_t no_more_time;
5296 signal(SIGALRM, no_more_time);
5297 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5299 if (available_money > available_manpower) {
5300 Pay consultant to port U-Boot;
5304 Download latest U-Boot source;
5306 Subscribe to u-boot mailing list;
5309 email("Hi, I am new to U-Boot, how do I get started?");
5312 Read the README file in the top level directory;
5313 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5314 Read applicable doc/*.README;
5315 Read the source, Luke;
5316 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5319 if (available_money > toLocalCurrency ($2500))
5322 Add a lot of aggravation and time;
5324 if (a similar board exists) { /* hopefully... */
5325 cp -a board/<similar> board/<myboard>
5326 cp include/configs/<similar>.h include/configs/<myboard>.h
5328 Create your own board support subdirectory;
5329 Create your own board include/configs/<myboard>.h file;
5331 Edit new board/<myboard> files
5332 Edit new include/configs/<myboard>.h
5337 Add / modify source code;
5341 email("Hi, I am having problems...");
5343 Send patch file to the U-Boot email list;
5344 if (reasonable critiques)
5345 Incorporate improvements from email list code review;
5347 Defend code as written;
5353 void no_more_time (int sig)
5362 All contributions to U-Boot should conform to the Linux kernel
5363 coding style; see the file "Documentation/CodingStyle" and the script
5364 "scripts/Lindent" in your Linux kernel source directory.
5366 Source files originating from a different project (for example the
5367 MTD subsystem) are generally exempt from these guidelines and are not
5368 reformated to ease subsequent migration to newer versions of those
5371 Please note that U-Boot is implemented in C (and to some small parts in
5372 Assembler); no C++ is used, so please do not use C++ style comments (//)
5375 Please also stick to the following formatting rules:
5376 - remove any trailing white space
5377 - use TAB characters for indentation and vertical alignment, not spaces
5378 - make sure NOT to use DOS '\r\n' line feeds
5379 - do not add more than 2 consecutive empty lines to source files
5380 - do not add trailing empty lines to source files
5382 Submissions which do not conform to the standards may be returned
5383 with a request to reformat the changes.
5389 Since the number of patches for U-Boot is growing, we need to
5390 establish some rules. Submissions which do not conform to these rules
5391 may be rejected, even when they contain important and valuable stuff.
5393 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5395 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5396 see http://lists.denx.de/mailman/listinfo/u-boot
5398 When you send a patch, please include the following information with
5401 * For bug fixes: a description of the bug and how your patch fixes
5402 this bug. Please try to include a way of demonstrating that the
5403 patch actually fixes something.
5405 * For new features: a description of the feature and your
5408 * A CHANGELOG entry as plaintext (separate from the patch)
5410 * For major contributions, your entry to the CREDITS file
5412 * When you add support for a new board, don't forget to add this
5413 board to the MAINTAINERS file, too.
5415 * If your patch adds new configuration options, don't forget to
5416 document these in the README file.
5418 * The patch itself. If you are using git (which is *strongly*
5419 recommended) you can easily generate the patch using the
5420 "git format-patch". If you then use "git send-email" to send it to
5421 the U-Boot mailing list, you will avoid most of the common problems
5422 with some other mail clients.
5424 If you cannot use git, use "diff -purN OLD NEW". If your version of
5425 diff does not support these options, then get the latest version of
5428 The current directory when running this command shall be the parent
5429 directory of the U-Boot source tree (i. e. please make sure that
5430 your patch includes sufficient directory information for the
5433 We prefer patches as plain text. MIME attachments are discouraged,
5434 and compressed attachments must not be used.
5436 * If one logical set of modifications affects or creates several
5437 files, all these changes shall be submitted in a SINGLE patch file.
5439 * Changesets that contain different, unrelated modifications shall be
5440 submitted as SEPARATE patches, one patch per changeset.
5445 * Before sending the patch, run the MAKEALL script on your patched
5446 source tree and make sure that no errors or warnings are reported
5447 for any of the boards.
5449 * Keep your modifications to the necessary minimum: A patch
5450 containing several unrelated changes or arbitrary reformats will be
5451 returned with a request to re-formatting / split it.
5453 * If you modify existing code, make sure that your new code does not
5454 add to the memory footprint of the code ;-) Small is beautiful!
5455 When adding new features, these should compile conditionally only
5456 (using #ifdef), and the resulting code with the new feature
5457 disabled must not need more memory than the old code without your
5460 * Remember that there is a size limit of 100 kB per message on the
5461 u-boot mailing list. Bigger patches will be moderated. If they are
5462 reasonable and not too big, they will be acknowledged. But patches
5463 bigger than the size limit should be avoided.