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_SPLASH_SCREEN_ALIGN
1535 If this option is set the splash image can be freely positioned
1536 on the screen. Environment variable "splashpos" specifies the
1537 position as "x,y". If a positive number is given it is used as
1538 number of pixel from left/top. If a negative number is given it
1539 is used as number of pixel from right/bottom. You can also
1540 specify 'm' for centering the image.
1543 setenv splashpos m,m
1544 => image at center of screen
1546 setenv splashpos 30,20
1547 => image at x = 30 and y = 20
1549 setenv splashpos -10,m
1550 => vertically centered image
1551 at x = dspWidth - bmpWidth - 9
1553 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1555 If this option is set, additionally to standard BMP
1556 images, gzipped BMP images can be displayed via the
1557 splashscreen support or the bmp command.
1559 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1561 If this option is set, 8-bit RLE compressed BMP images
1562 can be displayed via the splashscreen support or the
1565 - Do compresssing for memory range:
1568 If this option is set, it would use zlib deflate method
1569 to compress the specified memory at its best effort.
1571 - Compression support:
1574 If this option is set, support for bzip2 compressed
1575 images is included. If not, only uncompressed and gzip
1576 compressed images are supported.
1578 NOTE: the bzip2 algorithm requires a lot of RAM, so
1579 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1584 If this option is set, support for lzma compressed
1587 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1588 requires an amount of dynamic memory that is given by the
1591 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1593 Where lc and lp stand for, respectively, Literal context bits
1594 and Literal pos bits.
1596 This value is upper-bounded by 14MB in the worst case. Anyway,
1597 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1598 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1599 a very small buffer.
1601 Use the lzmainfo tool to determinate the lc and lp values and
1602 then calculate the amount of needed dynamic memory (ensuring
1603 the appropriate CONFIG_SYS_MALLOC_LEN value).
1608 The address of PHY on MII bus.
1610 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1612 The clock frequency of the MII bus
1616 If this option is set, support for speed/duplex
1617 detection of gigabit PHY is included.
1619 CONFIG_PHY_RESET_DELAY
1621 Some PHY like Intel LXT971A need extra delay after
1622 reset before any MII register access is possible.
1623 For such PHY, set this option to the usec delay
1624 required. (minimum 300usec for LXT971A)
1626 CONFIG_PHY_CMD_DELAY (ppc4xx)
1628 Some PHY like Intel LXT971A need extra delay after
1629 command issued before MII status register can be read
1639 Define a default value for Ethernet address to use
1640 for the respective Ethernet interface, in case this
1641 is not determined automatically.
1646 Define a default value for the IP address to use for
1647 the default Ethernet interface, in case this is not
1648 determined through e.g. bootp.
1649 (Environment variable "ipaddr")
1651 - Server IP address:
1654 Defines a default value for the IP address of a TFTP
1655 server to contact when using the "tftboot" command.
1656 (Environment variable "serverip")
1658 CONFIG_KEEP_SERVERADDR
1660 Keeps the server's MAC address, in the env 'serveraddr'
1661 for passing to bootargs (like Linux's netconsole option)
1663 - Gateway IP address:
1666 Defines a default value for the IP address of the
1667 default router where packets to other networks are
1669 (Environment variable "gatewayip")
1674 Defines a default value for the subnet mask (or
1675 routing prefix) which is used to determine if an IP
1676 address belongs to the local subnet or needs to be
1677 forwarded through a router.
1678 (Environment variable "netmask")
1680 - Multicast TFTP Mode:
1683 Defines whether you want to support multicast TFTP as per
1684 rfc-2090; for example to work with atftp. Lets lots of targets
1685 tftp down the same boot image concurrently. Note: the Ethernet
1686 driver in use must provide a function: mcast() to join/leave a
1689 - BOOTP Recovery Mode:
1690 CONFIG_BOOTP_RANDOM_DELAY
1692 If you have many targets in a network that try to
1693 boot using BOOTP, you may want to avoid that all
1694 systems send out BOOTP requests at precisely the same
1695 moment (which would happen for instance at recovery
1696 from a power failure, when all systems will try to
1697 boot, thus flooding the BOOTP server. Defining
1698 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1699 inserted before sending out BOOTP requests. The
1700 following delays are inserted then:
1702 1st BOOTP request: delay 0 ... 1 sec
1703 2nd BOOTP request: delay 0 ... 2 sec
1704 3rd BOOTP request: delay 0 ... 4 sec
1706 BOOTP requests: delay 0 ... 8 sec
1708 - DHCP Advanced Options:
1709 You can fine tune the DHCP functionality by defining
1710 CONFIG_BOOTP_* symbols:
1712 CONFIG_BOOTP_SUBNETMASK
1713 CONFIG_BOOTP_GATEWAY
1714 CONFIG_BOOTP_HOSTNAME
1715 CONFIG_BOOTP_NISDOMAIN
1716 CONFIG_BOOTP_BOOTPATH
1717 CONFIG_BOOTP_BOOTFILESIZE
1720 CONFIG_BOOTP_SEND_HOSTNAME
1721 CONFIG_BOOTP_NTPSERVER
1722 CONFIG_BOOTP_TIMEOFFSET
1723 CONFIG_BOOTP_VENDOREX
1724 CONFIG_BOOTP_MAY_FAIL
1726 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1727 environment variable, not the BOOTP server.
1729 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1730 after the configured retry count, the call will fail
1731 instead of starting over. This can be used to fail over
1732 to Link-local IP address configuration if the DHCP server
1735 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1736 serverip from a DHCP server, it is possible that more
1737 than one DNS serverip is offered to the client.
1738 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1739 serverip will be stored in the additional environment
1740 variable "dnsip2". The first DNS serverip is always
1741 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1744 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1745 to do a dynamic update of a DNS server. To do this, they
1746 need the hostname of the DHCP requester.
1747 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1748 of the "hostname" environment variable is passed as
1749 option 12 to the DHCP server.
1751 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1753 A 32bit value in microseconds for a delay between
1754 receiving a "DHCP Offer" and sending the "DHCP Request".
1755 This fixes a problem with certain DHCP servers that don't
1756 respond 100% of the time to a "DHCP request". E.g. On an
1757 AT91RM9200 processor running at 180MHz, this delay needed
1758 to be *at least* 15,000 usec before a Windows Server 2003
1759 DHCP server would reply 100% of the time. I recommend at
1760 least 50,000 usec to be safe. The alternative is to hope
1761 that one of the retries will be successful but note that
1762 the DHCP timeout and retry process takes a longer than
1765 - Link-local IP address negotiation:
1766 Negotiate with other link-local clients on the local network
1767 for an address that doesn't require explicit configuration.
1768 This is especially useful if a DHCP server cannot be guaranteed
1769 to exist in all environments that the device must operate.
1771 See doc/README.link-local for more information.
1774 CONFIG_CDP_DEVICE_ID
1776 The device id used in CDP trigger frames.
1778 CONFIG_CDP_DEVICE_ID_PREFIX
1780 A two character string which is prefixed to the MAC address
1785 A printf format string which contains the ascii name of
1786 the port. Normally is set to "eth%d" which sets
1787 eth0 for the first Ethernet, eth1 for the second etc.
1789 CONFIG_CDP_CAPABILITIES
1791 A 32bit integer which indicates the device capabilities;
1792 0x00000010 for a normal host which does not forwards.
1796 An ascii string containing the version of the software.
1800 An ascii string containing the name of the platform.
1804 A 32bit integer sent on the trigger.
1806 CONFIG_CDP_POWER_CONSUMPTION
1808 A 16bit integer containing the power consumption of the
1809 device in .1 of milliwatts.
1811 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1813 A byte containing the id of the VLAN.
1815 - Status LED: CONFIG_STATUS_LED
1817 Several configurations allow to display the current
1818 status using a LED. For instance, the LED will blink
1819 fast while running U-Boot code, stop blinking as
1820 soon as a reply to a BOOTP request was received, and
1821 start blinking slow once the Linux kernel is running
1822 (supported by a status LED driver in the Linux
1823 kernel). Defining CONFIG_STATUS_LED enables this
1826 - CAN Support: CONFIG_CAN_DRIVER
1828 Defining CONFIG_CAN_DRIVER enables CAN driver support
1829 on those systems that support this (optional)
1830 feature, like the TQM8xxL modules.
1832 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1834 These enable I2C serial bus commands. Defining either of
1835 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1836 include the appropriate I2C driver for the selected CPU.
1838 This will allow you to use i2c commands at the u-boot
1839 command line (as long as you set CONFIG_CMD_I2C in
1840 CONFIG_COMMANDS) and communicate with i2c based realtime
1841 clock chips. See common/cmd_i2c.c for a description of the
1842 command line interface.
1844 CONFIG_HARD_I2C selects a hardware I2C controller.
1846 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1847 bit-banging) driver instead of CPM or similar hardware
1850 There are several other quantities that must also be
1851 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1853 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1854 to be the frequency (in Hz) at which you wish your i2c bus
1855 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1856 the CPU's i2c node address).
1858 Now, the u-boot i2c code for the mpc8xx
1859 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1860 and so its address should therefore be cleared to 0 (See,
1861 eg, MPC823e User's Manual p.16-473). So, set
1862 CONFIG_SYS_I2C_SLAVE to 0.
1864 CONFIG_SYS_I2C_INIT_MPC5XXX
1866 When a board is reset during an i2c bus transfer
1867 chips might think that the current transfer is still
1868 in progress. Reset the slave devices by sending start
1869 commands until the slave device responds.
1871 That's all that's required for CONFIG_HARD_I2C.
1873 If you use the software i2c interface (CONFIG_SOFT_I2C)
1874 then the following macros need to be defined (examples are
1875 from include/configs/lwmon.h):
1879 (Optional). Any commands necessary to enable the I2C
1880 controller or configure ports.
1882 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1886 (Only for MPC8260 CPU). The I/O port to use (the code
1887 assumes both bits are on the same port). Valid values
1888 are 0..3 for ports A..D.
1892 The code necessary to make the I2C data line active
1893 (driven). If the data line is open collector, this
1896 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1900 The code necessary to make the I2C data line tri-stated
1901 (inactive). If the data line is open collector, this
1904 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1908 Code that returns TRUE if the I2C data line is high,
1911 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1915 If <bit> is TRUE, sets the I2C data line high. If it
1916 is FALSE, it clears it (low).
1918 eg: #define I2C_SDA(bit) \
1919 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1920 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1924 If <bit> is TRUE, sets the I2C clock line high. If it
1925 is FALSE, it clears it (low).
1927 eg: #define I2C_SCL(bit) \
1928 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1929 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1933 This delay is invoked four times per clock cycle so this
1934 controls the rate of data transfer. The data rate thus
1935 is 1 / (I2C_DELAY * 4). Often defined to be something
1938 #define I2C_DELAY udelay(2)
1940 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1942 If your arch supports the generic GPIO framework (asm/gpio.h),
1943 then you may alternatively define the two GPIOs that are to be
1944 used as SCL / SDA. Any of the previous I2C_xxx macros will
1945 have GPIO-based defaults assigned to them as appropriate.
1947 You should define these to the GPIO value as given directly to
1948 the generic GPIO functions.
1950 CONFIG_SYS_I2C_INIT_BOARD
1952 When a board is reset during an i2c bus transfer
1953 chips might think that the current transfer is still
1954 in progress. On some boards it is possible to access
1955 the i2c SCLK line directly, either by using the
1956 processor pin as a GPIO or by having a second pin
1957 connected to the bus. If this option is defined a
1958 custom i2c_init_board() routine in boards/xxx/board.c
1959 is run early in the boot sequence.
1961 CONFIG_SYS_I2C_BOARD_LATE_INIT
1963 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1964 defined a custom i2c_board_late_init() routine in
1965 boards/xxx/board.c is run AFTER the operations in i2c_init()
1966 is completed. This callpoint can be used to unreset i2c bus
1967 using CPU i2c controller register accesses for CPUs whose i2c
1968 controller provide such a method. It is called at the end of
1969 i2c_init() to allow i2c_init operations to setup the i2c bus
1970 controller on the CPU (e.g. setting bus speed & slave address).
1972 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1974 This option enables configuration of bi_iic_fast[] flags
1975 in u-boot bd_info structure based on u-boot environment
1976 variable "i2cfast". (see also i2cfast)
1978 CONFIG_I2C_MULTI_BUS
1980 This option allows the use of multiple I2C buses, each of which
1981 must have a controller. At any point in time, only one bus is
1982 active. To switch to a different bus, use the 'i2c dev' command.
1983 Note that bus numbering is zero-based.
1985 CONFIG_SYS_I2C_NOPROBES
1987 This option specifies a list of I2C devices that will be skipped
1988 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1989 is set, specify a list of bus-device pairs. Otherwise, specify
1990 a 1D array of device addresses
1993 #undef CONFIG_I2C_MULTI_BUS
1994 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1996 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1998 #define CONFIG_I2C_MULTI_BUS
1999 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2001 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2003 CONFIG_SYS_SPD_BUS_NUM
2005 If defined, then this indicates the I2C bus number for DDR SPD.
2006 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2008 CONFIG_SYS_RTC_BUS_NUM
2010 If defined, then this indicates the I2C bus number for the RTC.
2011 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2013 CONFIG_SYS_DTT_BUS_NUM
2015 If defined, then this indicates the I2C bus number for the DTT.
2016 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2018 CONFIG_SYS_I2C_DTT_ADDR:
2020 If defined, specifies the I2C address of the DTT device.
2021 If not defined, then U-Boot uses predefined value for
2022 specified DTT device.
2026 Define this option if you want to use Freescale's I2C driver in
2027 drivers/i2c/fsl_i2c.c.
2031 Define this option if you have I2C devices reached over 1 .. n
2032 I2C Muxes like the pca9544a. This option addes a new I2C
2033 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2034 new I2C Bus to the existing I2C Busses. If you select the
2035 new Bus with "i2c dev", u-bbot sends first the commandos for
2036 the muxes to activate this new "bus".
2038 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2042 Adding a new I2C Bus reached over 2 pca9544a muxes
2043 The First mux with address 70 and channel 6
2044 The Second mux with address 71 and channel 4
2046 => i2c bus pca9544a:70:6:pca9544a:71:4
2048 Use the "i2c bus" command without parameter, to get a list
2049 of I2C Busses with muxes:
2052 Busses reached over muxes:
2054 reached over Mux(es):
2057 reached over Mux(es):
2062 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2063 u-boot first sends the command to the mux@70 to enable
2064 channel 6, and then the command to the mux@71 to enable
2067 After that, you can use the "normal" i2c commands as
2068 usual to communicate with your I2C devices behind
2071 This option is actually implemented for the bitbanging
2072 algorithm in common/soft_i2c.c and for the Hardware I2C
2073 Bus on the MPC8260. But it should be not so difficult
2074 to add this option to other architectures.
2076 CONFIG_SOFT_I2C_READ_REPEATED_START
2078 defining this will force the i2c_read() function in
2079 the soft_i2c driver to perform an I2C repeated start
2080 between writing the address pointer and reading the
2081 data. If this define is omitted the default behaviour
2082 of doing a stop-start sequence will be used. Most I2C
2083 devices can use either method, but some require one or
2086 - SPI Support: CONFIG_SPI
2088 Enables SPI driver (so far only tested with
2089 SPI EEPROM, also an instance works with Crystal A/D and
2090 D/As on the SACSng board)
2094 Enables the driver for SPI controller on SuperH. Currently
2095 only SH7757 is supported.
2099 Enables extended (16-bit) SPI EEPROM addressing.
2100 (symmetrical to CONFIG_I2C_X)
2104 Enables a software (bit-bang) SPI driver rather than
2105 using hardware support. This is a general purpose
2106 driver that only requires three general I/O port pins
2107 (two outputs, one input) to function. If this is
2108 defined, the board configuration must define several
2109 SPI configuration items (port pins to use, etc). For
2110 an example, see include/configs/sacsng.h.
2114 Enables a hardware SPI driver for general-purpose reads
2115 and writes. As with CONFIG_SOFT_SPI, the board configuration
2116 must define a list of chip-select function pointers.
2117 Currently supported on some MPC8xxx processors. For an
2118 example, see include/configs/mpc8349emds.h.
2122 Enables the driver for the SPI controllers on i.MX and MXC
2123 SoCs. Currently i.MX31/35/51 are supported.
2125 - FPGA Support: CONFIG_FPGA
2127 Enables FPGA subsystem.
2129 CONFIG_FPGA_<vendor>
2131 Enables support for specific chip vendors.
2134 CONFIG_FPGA_<family>
2136 Enables support for FPGA family.
2137 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2141 Specify the number of FPGA devices to support.
2143 CONFIG_SYS_FPGA_PROG_FEEDBACK
2145 Enable printing of hash marks during FPGA configuration.
2147 CONFIG_SYS_FPGA_CHECK_BUSY
2149 Enable checks on FPGA configuration interface busy
2150 status by the configuration function. This option
2151 will require a board or device specific function to
2156 If defined, a function that provides delays in the FPGA
2157 configuration driver.
2159 CONFIG_SYS_FPGA_CHECK_CTRLC
2160 Allow Control-C to interrupt FPGA configuration
2162 CONFIG_SYS_FPGA_CHECK_ERROR
2164 Check for configuration errors during FPGA bitfile
2165 loading. For example, abort during Virtex II
2166 configuration if the INIT_B line goes low (which
2167 indicated a CRC error).
2169 CONFIG_SYS_FPGA_WAIT_INIT
2171 Maximum time to wait for the INIT_B line to deassert
2172 after PROB_B has been deasserted during a Virtex II
2173 FPGA configuration sequence. The default time is 500
2176 CONFIG_SYS_FPGA_WAIT_BUSY
2178 Maximum time to wait for BUSY to deassert during
2179 Virtex II FPGA configuration. The default is 5 ms.
2181 CONFIG_SYS_FPGA_WAIT_CONFIG
2183 Time to wait after FPGA configuration. The default is
2186 - Configuration Management:
2189 If defined, this string will be added to the U-Boot
2190 version information (U_BOOT_VERSION)
2192 - Vendor Parameter Protection:
2194 U-Boot considers the values of the environment
2195 variables "serial#" (Board Serial Number) and
2196 "ethaddr" (Ethernet Address) to be parameters that
2197 are set once by the board vendor / manufacturer, and
2198 protects these variables from casual modification by
2199 the user. Once set, these variables are read-only,
2200 and write or delete attempts are rejected. You can
2201 change this behaviour:
2203 If CONFIG_ENV_OVERWRITE is #defined in your config
2204 file, the write protection for vendor parameters is
2205 completely disabled. Anybody can change or delete
2208 Alternatively, if you #define _both_ CONFIG_ETHADDR
2209 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2210 Ethernet address is installed in the environment,
2211 which can be changed exactly ONCE by the user. [The
2212 serial# is unaffected by this, i. e. it remains
2215 The same can be accomplished in a more flexible way
2216 for any variable by configuring the type of access
2217 to allow for those variables in the ".flags" variable
2218 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2223 Define this variable to enable the reservation of
2224 "protected RAM", i. e. RAM which is not overwritten
2225 by U-Boot. Define CONFIG_PRAM to hold the number of
2226 kB you want to reserve for pRAM. You can overwrite
2227 this default value by defining an environment
2228 variable "pram" to the number of kB you want to
2229 reserve. Note that the board info structure will
2230 still show the full amount of RAM. If pRAM is
2231 reserved, a new environment variable "mem" will
2232 automatically be defined to hold the amount of
2233 remaining RAM in a form that can be passed as boot
2234 argument to Linux, for instance like that:
2236 setenv bootargs ... mem=\${mem}
2239 This way you can tell Linux not to use this memory,
2240 either, which results in a memory region that will
2241 not be affected by reboots.
2243 *WARNING* If your board configuration uses automatic
2244 detection of the RAM size, you must make sure that
2245 this memory test is non-destructive. So far, the
2246 following board configurations are known to be
2249 IVMS8, IVML24, SPD8xx, TQM8xxL,
2250 HERMES, IP860, RPXlite, LWMON,
2253 - Access to physical memory region (> 4GB)
2254 Some basic support is provided for operations on memory not
2255 normally accessible to U-Boot - e.g. some architectures
2256 support access to more than 4GB of memory on 32-bit
2257 machines using physical address extension or similar.
2258 Define CONFIG_PHYSMEM to access this basic support, which
2259 currently only supports clearing the memory.
2264 Define this variable to stop the system in case of a
2265 fatal error, so that you have to reset it manually.
2266 This is probably NOT a good idea for an embedded
2267 system where you want the system to reboot
2268 automatically as fast as possible, but it may be
2269 useful during development since you can try to debug
2270 the conditions that lead to the situation.
2272 CONFIG_NET_RETRY_COUNT
2274 This variable defines the number of retries for
2275 network operations like ARP, RARP, TFTP, or BOOTP
2276 before giving up the operation. If not defined, a
2277 default value of 5 is used.
2281 Timeout waiting for an ARP reply in milliseconds.
2285 Timeout in milliseconds used in NFS protocol.
2286 If you encounter "ERROR: Cannot umount" in nfs command,
2287 try longer timeout such as
2288 #define CONFIG_NFS_TIMEOUT 10000UL
2290 - Command Interpreter:
2291 CONFIG_AUTO_COMPLETE
2293 Enable auto completion of commands using TAB.
2295 Note that this feature has NOT been implemented yet
2296 for the "hush" shell.
2299 CONFIG_SYS_HUSH_PARSER
2301 Define this variable to enable the "hush" shell (from
2302 Busybox) as command line interpreter, thus enabling
2303 powerful command line syntax like
2304 if...then...else...fi conditionals or `&&' and '||'
2305 constructs ("shell scripts").
2307 If undefined, you get the old, much simpler behaviour
2308 with a somewhat smaller memory footprint.
2311 CONFIG_SYS_PROMPT_HUSH_PS2
2313 This defines the secondary prompt string, which is
2314 printed when the command interpreter needs more input
2315 to complete a command. Usually "> ".
2319 In the current implementation, the local variables
2320 space and global environment variables space are
2321 separated. Local variables are those you define by
2322 simply typing `name=value'. To access a local
2323 variable later on, you have write `$name' or
2324 `${name}'; to execute the contents of a variable
2325 directly type `$name' at the command prompt.
2327 Global environment variables are those you use
2328 setenv/printenv to work with. To run a command stored
2329 in such a variable, you need to use the run command,
2330 and you must not use the '$' sign to access them.
2332 To store commands and special characters in a
2333 variable, please use double quotation marks
2334 surrounding the whole text of the variable, instead
2335 of the backslashes before semicolons and special
2338 - Commandline Editing and History:
2339 CONFIG_CMDLINE_EDITING
2341 Enable editing and History functions for interactive
2342 commandline input operations
2344 - Default Environment:
2345 CONFIG_EXTRA_ENV_SETTINGS
2347 Define this to contain any number of null terminated
2348 strings (variable = value pairs) that will be part of
2349 the default environment compiled into the boot image.
2351 For example, place something like this in your
2352 board's config file:
2354 #define CONFIG_EXTRA_ENV_SETTINGS \
2358 Warning: This method is based on knowledge about the
2359 internal format how the environment is stored by the
2360 U-Boot code. This is NOT an official, exported
2361 interface! Although it is unlikely that this format
2362 will change soon, there is no guarantee either.
2363 You better know what you are doing here.
2365 Note: overly (ab)use of the default environment is
2366 discouraged. Make sure to check other ways to preset
2367 the environment like the "source" command or the
2370 CONFIG_ENV_VARS_UBOOT_CONFIG
2372 Define this in order to add variables describing the
2373 U-Boot build configuration to the default environment.
2374 These will be named arch, cpu, board, vendor, and soc.
2376 Enabling this option will cause the following to be defined:
2384 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2386 Define this in order to add variables describing certain
2387 run-time determined information about the hardware to the
2388 environment. These will be named board_name, board_rev.
2390 CONFIG_DELAY_ENVIRONMENT
2392 Normally the environment is loaded when the board is
2393 intialised so that it is available to U-Boot. This inhibits
2394 that so that the environment is not available until
2395 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2396 this is instead controlled by the value of
2397 /config/load-environment.
2399 - DataFlash Support:
2400 CONFIG_HAS_DATAFLASH
2402 Defining this option enables DataFlash features and
2403 allows to read/write in Dataflash via the standard
2406 - Serial Flash support
2409 Defining this option enables SPI flash commands
2410 'sf probe/read/write/erase/update'.
2412 Usage requires an initial 'probe' to define the serial
2413 flash parameters, followed by read/write/erase/update
2416 The following defaults may be provided by the platform
2417 to handle the common case when only a single serial
2418 flash is present on the system.
2420 CONFIG_SF_DEFAULT_BUS Bus identifier
2421 CONFIG_SF_DEFAULT_CS Chip-select
2422 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2423 CONFIG_SF_DEFAULT_SPEED in Hz
2427 Define this option to include a destructive SPI flash
2430 - SystemACE Support:
2433 Adding this option adds support for Xilinx SystemACE
2434 chips attached via some sort of local bus. The address
2435 of the chip must also be defined in the
2436 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2438 #define CONFIG_SYSTEMACE
2439 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2441 When SystemACE support is added, the "ace" device type
2442 becomes available to the fat commands, i.e. fatls.
2444 - TFTP Fixed UDP Port:
2447 If this is defined, the environment variable tftpsrcp
2448 is used to supply the TFTP UDP source port value.
2449 If tftpsrcp isn't defined, the normal pseudo-random port
2450 number generator is used.
2452 Also, the environment variable tftpdstp is used to supply
2453 the TFTP UDP destination port value. If tftpdstp isn't
2454 defined, the normal port 69 is used.
2456 The purpose for tftpsrcp is to allow a TFTP server to
2457 blindly start the TFTP transfer using the pre-configured
2458 target IP address and UDP port. This has the effect of
2459 "punching through" the (Windows XP) firewall, allowing
2460 the remainder of the TFTP transfer to proceed normally.
2461 A better solution is to properly configure the firewall,
2462 but sometimes that is not allowed.
2467 This enables a generic 'hash' command which can produce
2468 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2472 Enable the hash verify command (hash -v). This adds to code
2475 CONFIG_SHA1 - support SHA1 hashing
2476 CONFIG_SHA256 - support SHA256 hashing
2478 Note: There is also a sha1sum command, which should perhaps
2479 be deprecated in favour of 'hash sha1'.
2481 - Show boot progress:
2482 CONFIG_SHOW_BOOT_PROGRESS
2484 Defining this option allows to add some board-
2485 specific code (calling a user-provided function
2486 "show_boot_progress(int)") that enables you to show
2487 the system's boot progress on some display (for
2488 example, some LED's) on your board. At the moment,
2489 the following checkpoints are implemented:
2491 - Detailed boot stage timing
2493 Define this option to get detailed timing of each stage
2494 of the boot process.
2496 CONFIG_BOOTSTAGE_USER_COUNT
2497 This is the number of available user bootstage records.
2498 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2499 a new ID will be allocated from this stash. If you exceed
2500 the limit, recording will stop.
2502 CONFIG_BOOTSTAGE_REPORT
2503 Define this to print a report before boot, similar to this:
2505 Timer summary in microseconds:
2508 3,575,678 3,575,678 board_init_f start
2509 3,575,695 17 arch_cpu_init A9
2510 3,575,777 82 arch_cpu_init done
2511 3,659,598 83,821 board_init_r start
2512 3,910,375 250,777 main_loop
2513 29,916,167 26,005,792 bootm_start
2514 30,361,327 445,160 start_kernel
2516 CONFIG_CMD_BOOTSTAGE
2517 Add a 'bootstage' command which supports printing a report
2518 and un/stashing of bootstage data.
2520 CONFIG_BOOTSTAGE_FDT
2521 Stash the bootstage information in the FDT. A root 'bootstage'
2522 node is created with each bootstage id as a child. Each child
2523 has a 'name' property and either 'mark' containing the
2524 mark time in microsecond, or 'accum' containing the
2525 accumulated time for that bootstage id in microseconds.
2530 name = "board_init_f";
2539 Code in the Linux kernel can find this in /proc/devicetree.
2541 Legacy uImage format:
2544 1 common/cmd_bootm.c before attempting to boot an image
2545 -1 common/cmd_bootm.c Image header has bad magic number
2546 2 common/cmd_bootm.c Image header has correct magic number
2547 -2 common/cmd_bootm.c Image header has bad checksum
2548 3 common/cmd_bootm.c Image header has correct checksum
2549 -3 common/cmd_bootm.c Image data has bad checksum
2550 4 common/cmd_bootm.c Image data has correct checksum
2551 -4 common/cmd_bootm.c Image is for unsupported architecture
2552 5 common/cmd_bootm.c Architecture check OK
2553 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2554 6 common/cmd_bootm.c Image Type check OK
2555 -6 common/cmd_bootm.c gunzip uncompression error
2556 -7 common/cmd_bootm.c Unimplemented compression type
2557 7 common/cmd_bootm.c Uncompression OK
2558 8 common/cmd_bootm.c No uncompress/copy overwrite error
2559 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2561 9 common/image.c Start initial ramdisk verification
2562 -10 common/image.c Ramdisk header has bad magic number
2563 -11 common/image.c Ramdisk header has bad checksum
2564 10 common/image.c Ramdisk header is OK
2565 -12 common/image.c Ramdisk data has bad checksum
2566 11 common/image.c Ramdisk data has correct checksum
2567 12 common/image.c Ramdisk verification complete, start loading
2568 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2569 13 common/image.c Start multifile image verification
2570 14 common/image.c No initial ramdisk, no multifile, continue.
2572 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2574 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2575 -31 post/post.c POST test failed, detected by post_output_backlog()
2576 -32 post/post.c POST test failed, detected by post_run_single()
2578 34 common/cmd_doc.c before loading a Image from a DOC device
2579 -35 common/cmd_doc.c Bad usage of "doc" command
2580 35 common/cmd_doc.c correct usage of "doc" command
2581 -36 common/cmd_doc.c No boot device
2582 36 common/cmd_doc.c correct boot device
2583 -37 common/cmd_doc.c Unknown Chip ID on boot device
2584 37 common/cmd_doc.c correct chip ID found, device available
2585 -38 common/cmd_doc.c Read Error on boot device
2586 38 common/cmd_doc.c reading Image header from DOC device OK
2587 -39 common/cmd_doc.c Image header has bad magic number
2588 39 common/cmd_doc.c Image header has correct magic number
2589 -40 common/cmd_doc.c Error reading Image from DOC device
2590 40 common/cmd_doc.c Image header has correct magic number
2591 41 common/cmd_ide.c before loading a Image from a IDE device
2592 -42 common/cmd_ide.c Bad usage of "ide" command
2593 42 common/cmd_ide.c correct usage of "ide" command
2594 -43 common/cmd_ide.c No boot device
2595 43 common/cmd_ide.c boot device found
2596 -44 common/cmd_ide.c Device not available
2597 44 common/cmd_ide.c Device available
2598 -45 common/cmd_ide.c wrong partition selected
2599 45 common/cmd_ide.c partition selected
2600 -46 common/cmd_ide.c Unknown partition table
2601 46 common/cmd_ide.c valid partition table found
2602 -47 common/cmd_ide.c Invalid partition type
2603 47 common/cmd_ide.c correct partition type
2604 -48 common/cmd_ide.c Error reading Image Header on boot device
2605 48 common/cmd_ide.c reading Image Header from IDE device OK
2606 -49 common/cmd_ide.c Image header has bad magic number
2607 49 common/cmd_ide.c Image header has correct magic number
2608 -50 common/cmd_ide.c Image header has bad checksum
2609 50 common/cmd_ide.c Image header has correct checksum
2610 -51 common/cmd_ide.c Error reading Image from IDE device
2611 51 common/cmd_ide.c reading Image from IDE device OK
2612 52 common/cmd_nand.c before loading a Image from a NAND device
2613 -53 common/cmd_nand.c Bad usage of "nand" command
2614 53 common/cmd_nand.c correct usage of "nand" command
2615 -54 common/cmd_nand.c No boot device
2616 54 common/cmd_nand.c boot device found
2617 -55 common/cmd_nand.c Unknown Chip ID on boot device
2618 55 common/cmd_nand.c correct chip ID found, device available
2619 -56 common/cmd_nand.c Error reading Image Header on boot device
2620 56 common/cmd_nand.c reading Image Header from NAND device OK
2621 -57 common/cmd_nand.c Image header has bad magic number
2622 57 common/cmd_nand.c Image header has correct magic number
2623 -58 common/cmd_nand.c Error reading Image from NAND device
2624 58 common/cmd_nand.c reading Image from NAND device OK
2626 -60 common/env_common.c Environment has a bad CRC, using default
2628 64 net/eth.c starting with Ethernet configuration.
2629 -64 net/eth.c no Ethernet found.
2630 65 net/eth.c Ethernet found.
2632 -80 common/cmd_net.c usage wrong
2633 80 common/cmd_net.c before calling NetLoop()
2634 -81 common/cmd_net.c some error in NetLoop() occurred
2635 81 common/cmd_net.c NetLoop() back without error
2636 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2637 82 common/cmd_net.c trying automatic boot
2638 83 common/cmd_net.c running "source" command
2639 -83 common/cmd_net.c some error in automatic boot or "source" command
2640 84 common/cmd_net.c end without errors
2645 100 common/cmd_bootm.c Kernel FIT Image has correct format
2646 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2647 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2648 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2649 102 common/cmd_bootm.c Kernel unit name specified
2650 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2651 103 common/cmd_bootm.c Found configuration node
2652 104 common/cmd_bootm.c Got kernel subimage node offset
2653 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2654 105 common/cmd_bootm.c Kernel subimage hash verification OK
2655 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2656 106 common/cmd_bootm.c Architecture check OK
2657 -106 common/cmd_bootm.c Kernel subimage has wrong type
2658 107 common/cmd_bootm.c Kernel subimage type OK
2659 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2660 108 common/cmd_bootm.c Got kernel subimage data/size
2661 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2662 -109 common/cmd_bootm.c Can't get kernel subimage type
2663 -110 common/cmd_bootm.c Can't get kernel subimage comp
2664 -111 common/cmd_bootm.c Can't get kernel subimage os
2665 -112 common/cmd_bootm.c Can't get kernel subimage load address
2666 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2668 120 common/image.c Start initial ramdisk verification
2669 -120 common/image.c Ramdisk FIT image has incorrect format
2670 121 common/image.c Ramdisk FIT image has correct format
2671 122 common/image.c No ramdisk subimage unit name, using configuration
2672 -122 common/image.c Can't get configuration for ramdisk subimage
2673 123 common/image.c Ramdisk unit name specified
2674 -124 common/image.c Can't get ramdisk subimage node offset
2675 125 common/image.c Got ramdisk subimage node offset
2676 -125 common/image.c Ramdisk subimage hash verification failed
2677 126 common/image.c Ramdisk subimage hash verification OK
2678 -126 common/image.c Ramdisk subimage for unsupported architecture
2679 127 common/image.c Architecture check OK
2680 -127 common/image.c Can't get ramdisk subimage data/size
2681 128 common/image.c Got ramdisk subimage data/size
2682 129 common/image.c Can't get ramdisk load address
2683 -129 common/image.c Got ramdisk load address
2685 -130 common/cmd_doc.c Incorrect FIT image format
2686 131 common/cmd_doc.c FIT image format OK
2688 -140 common/cmd_ide.c Incorrect FIT image format
2689 141 common/cmd_ide.c FIT image format OK
2691 -150 common/cmd_nand.c Incorrect FIT image format
2692 151 common/cmd_nand.c FIT image format OK
2694 - FIT image support:
2696 Enable support for the FIT uImage format.
2698 CONFIG_FIT_BEST_MATCH
2699 When no configuration is explicitly selected, default to the
2700 one whose fdt's compatibility field best matches that of
2701 U-Boot itself. A match is considered "best" if it matches the
2702 most specific compatibility entry of U-Boot's fdt's root node.
2703 The order of entries in the configuration's fdt is ignored.
2705 - Standalone program support:
2706 CONFIG_STANDALONE_LOAD_ADDR
2708 This option defines a board specific value for the
2709 address where standalone program gets loaded, thus
2710 overwriting the architecture dependent default
2713 - Frame Buffer Address:
2716 Define CONFIG_FB_ADDR if you want to use specific
2717 address for frame buffer. This is typically the case
2718 when using a graphics controller has separate video
2719 memory. U-Boot will then place the frame buffer at
2720 the given address instead of dynamically reserving it
2721 in system RAM by calling lcd_setmem(), which grabs
2722 the memory for the frame buffer depending on the
2723 configured panel size.
2725 Please see board_init_f function.
2727 - Automatic software updates via TFTP server
2729 CONFIG_UPDATE_TFTP_CNT_MAX
2730 CONFIG_UPDATE_TFTP_MSEC_MAX
2732 These options enable and control the auto-update feature;
2733 for a more detailed description refer to doc/README.update.
2735 - MTD Support (mtdparts command, UBI support)
2738 Adds the MTD device infrastructure from the Linux kernel.
2739 Needed for mtdparts command support.
2741 CONFIG_MTD_PARTITIONS
2743 Adds the MTD partitioning infrastructure from the Linux
2744 kernel. Needed for UBI support.
2748 Enable building of SPL globally.
2751 LDSCRIPT for linking the SPL binary.
2754 Maximum binary size (text, data and rodata) of the SPL binary.
2756 CONFIG_SPL_TEXT_BASE
2757 TEXT_BASE for linking the SPL binary.
2759 CONFIG_SPL_RELOC_TEXT_BASE
2760 Address to relocate to. If unspecified, this is equal to
2761 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2763 CONFIG_SPL_BSS_START_ADDR
2764 Link address for the BSS within the SPL binary.
2766 CONFIG_SPL_BSS_MAX_SIZE
2767 Maximum binary size of the BSS section of the SPL binary.
2770 Adress of the start of the stack SPL will use
2772 CONFIG_SPL_RELOC_STACK
2773 Adress of the start of the stack SPL will use after
2774 relocation. If unspecified, this is equal to
2777 CONFIG_SYS_SPL_MALLOC_START
2778 Starting address of the malloc pool used in SPL.
2780 CONFIG_SYS_SPL_MALLOC_SIZE
2781 The size of the malloc pool used in SPL.
2783 CONFIG_SPL_FRAMEWORK
2784 Enable the SPL framework under common/. This framework
2785 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2786 NAND loading of the Linux Kernel.
2788 CONFIG_SPL_DISPLAY_PRINT
2789 For ARM, enable an optional function to print more information
2790 about the running system.
2792 CONFIG_SPL_INIT_MINIMAL
2793 Arch init code should be built for a very small image
2795 CONFIG_SPL_LIBCOMMON_SUPPORT
2796 Support for common/libcommon.o in SPL binary
2798 CONFIG_SPL_LIBDISK_SUPPORT
2799 Support for disk/libdisk.o in SPL binary
2801 CONFIG_SPL_I2C_SUPPORT
2802 Support for drivers/i2c/libi2c.o in SPL binary
2804 CONFIG_SPL_GPIO_SUPPORT
2805 Support for drivers/gpio/libgpio.o in SPL binary
2807 CONFIG_SPL_MMC_SUPPORT
2808 Support for drivers/mmc/libmmc.o in SPL binary
2810 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2811 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2812 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2813 Address, size and partition on the MMC to load U-Boot from
2814 when the MMC is being used in raw mode.
2816 CONFIG_SPL_FAT_SUPPORT
2817 Support for fs/fat/libfat.o in SPL binary
2819 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2820 Filename to read to load U-Boot when reading from FAT
2822 CONFIG_SPL_NAND_BASE
2823 Include nand_base.c in the SPL. Requires
2824 CONFIG_SPL_NAND_DRIVERS.
2826 CONFIG_SPL_NAND_DRIVERS
2827 SPL uses normal NAND drivers, not minimal drivers.
2830 Include standard software ECC in the SPL
2832 CONFIG_SPL_NAND_SIMPLE
2833 Support for NAND boot using simple NAND drivers that
2834 expose the cmd_ctrl() interface.
2836 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2837 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2838 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2839 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2840 CONFIG_SYS_NAND_ECCBYTES
2841 Defines the size and behavior of the NAND that SPL uses
2844 CONFIG_SYS_NAND_U_BOOT_OFFS
2845 Location in NAND to read U-Boot from
2847 CONFIG_SYS_NAND_U_BOOT_DST
2848 Location in memory to load U-Boot to
2850 CONFIG_SYS_NAND_U_BOOT_SIZE
2851 Size of image to load
2853 CONFIG_SYS_NAND_U_BOOT_START
2854 Entry point in loaded image to jump to
2856 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2857 Define this if you need to first read the OOB and then the
2858 data. This is used for example on davinci plattforms.
2860 CONFIG_SPL_OMAP3_ID_NAND
2861 Support for an OMAP3-specific set of functions to return the
2862 ID and MFR of the first attached NAND chip, if present.
2864 CONFIG_SPL_SERIAL_SUPPORT
2865 Support for drivers/serial/libserial.o in SPL binary
2867 CONFIG_SPL_SPI_FLASH_SUPPORT
2868 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2870 CONFIG_SPL_SPI_SUPPORT
2871 Support for drivers/spi/libspi.o in SPL binary
2873 CONFIG_SPL_RAM_DEVICE
2874 Support for running image already present in ram, in SPL binary
2876 CONFIG_SPL_LIBGENERIC_SUPPORT
2877 Support for lib/libgeneric.o in SPL binary
2880 Final target image containing SPL and payload. Some SPLs
2881 use an arch-specific makefile fragment instead, for
2882 example if more than one image needs to be produced.
2887 [so far only for SMDK2400 boards]
2889 - Modem support enable:
2890 CONFIG_MODEM_SUPPORT
2892 - RTS/CTS Flow control enable:
2895 - Modem debug support:
2896 CONFIG_MODEM_SUPPORT_DEBUG
2898 Enables debugging stuff (char screen[1024], dbg())
2899 for modem support. Useful only with BDI2000.
2901 - Interrupt support (PPC):
2903 There are common interrupt_init() and timer_interrupt()
2904 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2905 for CPU specific initialization. interrupt_init_cpu()
2906 should set decrementer_count to appropriate value. If
2907 CPU resets decrementer automatically after interrupt
2908 (ppc4xx) it should set decrementer_count to zero.
2909 timer_interrupt() calls timer_interrupt_cpu() for CPU
2910 specific handling. If board has watchdog / status_led
2911 / other_activity_monitor it works automatically from
2912 general timer_interrupt().
2916 In the target system modem support is enabled when a
2917 specific key (key combination) is pressed during
2918 power-on. Otherwise U-Boot will boot normally
2919 (autoboot). The key_pressed() function is called from
2920 board_init(). Currently key_pressed() is a dummy
2921 function, returning 1 and thus enabling modem
2924 If there are no modem init strings in the
2925 environment, U-Boot proceed to autoboot; the
2926 previous output (banner, info printfs) will be
2929 See also: doc/README.Modem
2931 Board initialization settings:
2932 ------------------------------
2934 During Initialization u-boot calls a number of board specific functions
2935 to allow the preparation of board specific prerequisites, e.g. pin setup
2936 before drivers are initialized. To enable these callbacks the
2937 following configuration macros have to be defined. Currently this is
2938 architecture specific, so please check arch/your_architecture/lib/board.c
2939 typically in board_init_f() and board_init_r().
2941 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2942 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2943 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2944 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2946 Configuration Settings:
2947 -----------------------
2949 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2950 undefine this when you're short of memory.
2952 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2953 width of the commands listed in the 'help' command output.
2955 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2956 prompt for user input.
2958 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2960 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2962 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2964 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2965 the application (usually a Linux kernel) when it is
2968 - CONFIG_SYS_BAUDRATE_TABLE:
2969 List of legal baudrate settings for this board.
2971 - CONFIG_SYS_CONSOLE_INFO_QUIET
2972 Suppress display of console information at boot.
2974 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2975 If the board specific function
2976 extern int overwrite_console (void);
2977 returns 1, the stdin, stderr and stdout are switched to the
2978 serial port, else the settings in the environment are used.
2980 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2981 Enable the call to overwrite_console().
2983 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2984 Enable overwrite of previous console environment settings.
2986 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2987 Begin and End addresses of the area used by the
2990 - CONFIG_SYS_ALT_MEMTEST:
2991 Enable an alternate, more extensive memory test.
2993 - CONFIG_SYS_MEMTEST_SCRATCH:
2994 Scratch address used by the alternate memory test
2995 You only need to set this if address zero isn't writeable
2997 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2998 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2999 this specified memory area will get subtracted from the top
3000 (end) of RAM and won't get "touched" at all by U-Boot. By
3001 fixing up gd->ram_size the Linux kernel should gets passed
3002 the now "corrected" memory size and won't touch it either.
3003 This should work for arch/ppc and arch/powerpc. Only Linux
3004 board ports in arch/powerpc with bootwrapper support that
3005 recalculate the memory size from the SDRAM controller setup
3006 will have to get fixed in Linux additionally.
3008 This option can be used as a workaround for the 440EPx/GRx
3009 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3012 WARNING: Please make sure that this value is a multiple of
3013 the Linux page size (normally 4k). If this is not the case,
3014 then the end address of the Linux memory will be located at a
3015 non page size aligned address and this could cause major
3018 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3019 Enable temporary baudrate change while serial download
3021 - CONFIG_SYS_SDRAM_BASE:
3022 Physical start address of SDRAM. _Must_ be 0 here.
3024 - CONFIG_SYS_MBIO_BASE:
3025 Physical start address of Motherboard I/O (if using a
3028 - CONFIG_SYS_FLASH_BASE:
3029 Physical start address of Flash memory.
3031 - CONFIG_SYS_MONITOR_BASE:
3032 Physical start address of boot monitor code (set by
3033 make config files to be same as the text base address
3034 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3035 CONFIG_SYS_FLASH_BASE when booting from flash.
3037 - CONFIG_SYS_MONITOR_LEN:
3038 Size of memory reserved for monitor code, used to
3039 determine _at_compile_time_ (!) if the environment is
3040 embedded within the U-Boot image, or in a separate
3043 - CONFIG_SYS_MALLOC_LEN:
3044 Size of DRAM reserved for malloc() use.
3046 - CONFIG_SYS_BOOTM_LEN:
3047 Normally compressed uImages are limited to an
3048 uncompressed size of 8 MBytes. If this is not enough,
3049 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3050 to adjust this setting to your needs.
3052 - CONFIG_SYS_BOOTMAPSZ:
3053 Maximum size of memory mapped by the startup code of
3054 the Linux kernel; all data that must be processed by
3055 the Linux kernel (bd_info, boot arguments, FDT blob if
3056 used) must be put below this limit, unless "bootm_low"
3057 enviroment variable is defined and non-zero. In such case
3058 all data for the Linux kernel must be between "bootm_low"
3059 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3060 variable "bootm_mapsize" will override the value of
3061 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3062 then the value in "bootm_size" will be used instead.
3064 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3065 Enable initrd_high functionality. If defined then the
3066 initrd_high feature is enabled and the bootm ramdisk subcommand
3069 - CONFIG_SYS_BOOT_GET_CMDLINE:
3070 Enables allocating and saving kernel cmdline in space between
3071 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3073 - CONFIG_SYS_BOOT_GET_KBD:
3074 Enables allocating and saving a kernel copy of the bd_info in
3075 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3077 - CONFIG_SYS_MAX_FLASH_BANKS:
3078 Max number of Flash memory banks
3080 - CONFIG_SYS_MAX_FLASH_SECT:
3081 Max number of sectors on a Flash chip
3083 - CONFIG_SYS_FLASH_ERASE_TOUT:
3084 Timeout for Flash erase operations (in ms)
3086 - CONFIG_SYS_FLASH_WRITE_TOUT:
3087 Timeout for Flash write operations (in ms)
3089 - CONFIG_SYS_FLASH_LOCK_TOUT
3090 Timeout for Flash set sector lock bit operation (in ms)
3092 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3093 Timeout for Flash clear lock bits operation (in ms)
3095 - CONFIG_SYS_FLASH_PROTECTION
3096 If defined, hardware flash sectors protection is used
3097 instead of U-Boot software protection.
3099 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3101 Enable TFTP transfers directly to flash memory;
3102 without this option such a download has to be
3103 performed in two steps: (1) download to RAM, and (2)
3104 copy from RAM to flash.
3106 The two-step approach is usually more reliable, since
3107 you can check if the download worked before you erase
3108 the flash, but in some situations (when system RAM is
3109 too limited to allow for a temporary copy of the
3110 downloaded image) this option may be very useful.
3112 - CONFIG_SYS_FLASH_CFI:
3113 Define if the flash driver uses extra elements in the
3114 common flash structure for storing flash geometry.
3116 - CONFIG_FLASH_CFI_DRIVER
3117 This option also enables the building of the cfi_flash driver
3118 in the drivers directory
3120 - CONFIG_FLASH_CFI_MTD
3121 This option enables the building of the cfi_mtd driver
3122 in the drivers directory. The driver exports CFI flash
3125 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3126 Use buffered writes to flash.
3128 - CONFIG_FLASH_SPANSION_S29WS_N
3129 s29ws-n MirrorBit flash has non-standard addresses for buffered
3132 - CONFIG_SYS_FLASH_QUIET_TEST
3133 If this option is defined, the common CFI flash doesn't
3134 print it's warning upon not recognized FLASH banks. This
3135 is useful, if some of the configured banks are only
3136 optionally available.
3138 - CONFIG_FLASH_SHOW_PROGRESS
3139 If defined (must be an integer), print out countdown
3140 digits and dots. Recommended value: 45 (9..1) for 80
3141 column displays, 15 (3..1) for 40 column displays.
3143 - CONFIG_SYS_RX_ETH_BUFFER:
3144 Defines the number of Ethernet receive buffers. On some
3145 Ethernet controllers it is recommended to set this value
3146 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3147 buffers can be full shortly after enabling the interface
3148 on high Ethernet traffic.
3149 Defaults to 4 if not defined.
3151 - CONFIG_ENV_MAX_ENTRIES
3153 Maximum number of entries in the hash table that is used
3154 internally to store the environment settings. The default
3155 setting is supposed to be generous and should work in most
3156 cases. This setting can be used to tune behaviour; see
3157 lib/hashtable.c for details.
3159 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3160 - CONFIG_ENV_FLAGS_LIST_STATIC
3161 Enable validation of the values given to enviroment variables when
3162 calling env set. Variables can be restricted to only decimal,
3163 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3164 the variables can also be restricted to IP address or MAC address.
3166 The format of the list is:
3167 type_attribute = [s|d|x|b|i|m]
3168 access_atribute = [a|r|o|c]
3169 attributes = type_attribute[access_atribute]
3170 entry = variable_name[:attributes]
3173 The type attributes are:
3174 s - String (default)
3177 b - Boolean ([1yYtT|0nNfF])
3181 The access attributes are:
3187 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3188 Define this to a list (string) to define the ".flags"
3189 envirnoment variable in the default or embedded environment.
3191 - CONFIG_ENV_FLAGS_LIST_STATIC
3192 Define this to a list (string) to define validation that
3193 should be done if an entry is not found in the ".flags"
3194 environment variable. To override a setting in the static
3195 list, simply add an entry for the same variable name to the
3198 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3199 If defined, don't allow the -f switch to env set override variable
3202 The following definitions that deal with the placement and management
3203 of environment data (variable area); in general, we support the
3204 following configurations:
3206 - CONFIG_BUILD_ENVCRC:
3208 Builds up envcrc with the target environment so that external utils
3209 may easily extract it and embed it in final U-Boot images.
3211 - CONFIG_ENV_IS_IN_FLASH:
3213 Define this if the environment is in flash memory.
3215 a) The environment occupies one whole flash sector, which is
3216 "embedded" in the text segment with the U-Boot code. This
3217 happens usually with "bottom boot sector" or "top boot
3218 sector" type flash chips, which have several smaller
3219 sectors at the start or the end. For instance, such a
3220 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3221 such a case you would place the environment in one of the
3222 4 kB sectors - with U-Boot code before and after it. With
3223 "top boot sector" type flash chips, you would put the
3224 environment in one of the last sectors, leaving a gap
3225 between U-Boot and the environment.
3227 - CONFIG_ENV_OFFSET:
3229 Offset of environment data (variable area) to the
3230 beginning of flash memory; for instance, with bottom boot
3231 type flash chips the second sector can be used: the offset
3232 for this sector is given here.
3234 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3238 This is just another way to specify the start address of
3239 the flash sector containing the environment (instead of
3242 - CONFIG_ENV_SECT_SIZE:
3244 Size of the sector containing the environment.
3247 b) Sometimes flash chips have few, equal sized, BIG sectors.
3248 In such a case you don't want to spend a whole sector for
3253 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3254 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3255 of this flash sector for the environment. This saves
3256 memory for the RAM copy of the environment.
3258 It may also save flash memory if you decide to use this
3259 when your environment is "embedded" within U-Boot code,
3260 since then the remainder of the flash sector could be used
3261 for U-Boot code. It should be pointed out that this is
3262 STRONGLY DISCOURAGED from a robustness point of view:
3263 updating the environment in flash makes it always
3264 necessary to erase the WHOLE sector. If something goes
3265 wrong before the contents has been restored from a copy in
3266 RAM, your target system will be dead.
3268 - CONFIG_ENV_ADDR_REDUND
3269 CONFIG_ENV_SIZE_REDUND
3271 These settings describe a second storage area used to hold
3272 a redundant copy of the environment data, so that there is
3273 a valid backup copy in case there is a power failure during
3274 a "saveenv" operation.
3276 BE CAREFUL! Any changes to the flash layout, and some changes to the
3277 source code will make it necessary to adapt <board>/u-boot.lds*
3281 - CONFIG_ENV_IS_IN_NVRAM:
3283 Define this if you have some non-volatile memory device
3284 (NVRAM, battery buffered SRAM) which you want to use for the
3290 These two #defines are used to determine the memory area you
3291 want to use for environment. It is assumed that this memory
3292 can just be read and written to, without any special
3295 BE CAREFUL! The first access to the environment happens quite early
3296 in U-Boot initalization (when we try to get the setting of for the
3297 console baudrate). You *MUST* have mapped your NVRAM area then, or
3300 Please note that even with NVRAM we still use a copy of the
3301 environment in RAM: we could work on NVRAM directly, but we want to
3302 keep settings there always unmodified except somebody uses "saveenv"
3303 to save the current settings.
3306 - CONFIG_ENV_IS_IN_EEPROM:
3308 Use this if you have an EEPROM or similar serial access
3309 device and a driver for it.
3311 - CONFIG_ENV_OFFSET:
3314 These two #defines specify the offset and size of the
3315 environment area within the total memory of your EEPROM.
3317 - CONFIG_SYS_I2C_EEPROM_ADDR:
3318 If defined, specified the chip address of the EEPROM device.
3319 The default address is zero.
3321 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3322 If defined, the number of bits used to address bytes in a
3323 single page in the EEPROM device. A 64 byte page, for example
3324 would require six bits.
3326 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3327 If defined, the number of milliseconds to delay between
3328 page writes. The default is zero milliseconds.
3330 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3331 The length in bytes of the EEPROM memory array address. Note
3332 that this is NOT the chip address length!
3334 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3335 EEPROM chips that implement "address overflow" are ones
3336 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3337 address and the extra bits end up in the "chip address" bit
3338 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3341 Note that we consider the length of the address field to
3342 still be one byte because the extra address bits are hidden
3343 in the chip address.
3345 - CONFIG_SYS_EEPROM_SIZE:
3346 The size in bytes of the EEPROM device.
3348 - CONFIG_ENV_EEPROM_IS_ON_I2C
3349 define this, if you have I2C and SPI activated, and your
3350 EEPROM, which holds the environment, is on the I2C bus.
3352 - CONFIG_I2C_ENV_EEPROM_BUS
3353 if you have an Environment on an EEPROM reached over
3354 I2C muxes, you can define here, how to reach this
3355 EEPROM. For example:
3357 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3359 EEPROM which holds the environment, is reached over
3360 a pca9547 i2c mux with address 0x70, channel 3.
3362 - CONFIG_ENV_IS_IN_DATAFLASH:
3364 Define this if you have a DataFlash memory device which you
3365 want to use for the environment.
3367 - CONFIG_ENV_OFFSET:
3371 These three #defines specify the offset and size of the
3372 environment area within the total memory of your DataFlash placed
3373 at the specified address.
3375 - CONFIG_ENV_IS_IN_REMOTE:
3377 Define this if you have a remote memory space which you
3378 want to use for the local device's environment.
3383 These two #defines specify the address and size of the
3384 environment area within the remote memory space. The
3385 local device can get the environment from remote memory
3386 space by SRIO or PCIE links.
3388 BE CAREFUL! For some special cases, the local device can not use
3389 "saveenv" command. For example, the local device will get the
3390 environment stored in a remote NOR flash by SRIO or PCIE link,
3391 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3393 - CONFIG_ENV_IS_IN_NAND:
3395 Define this if you have a NAND device which you want to use
3396 for the environment.
3398 - CONFIG_ENV_OFFSET:
3401 These two #defines specify the offset and size of the environment
3402 area within the first NAND device. CONFIG_ENV_OFFSET must be
3403 aligned to an erase block boundary.
3405 - CONFIG_ENV_OFFSET_REDUND (optional):
3407 This setting describes a second storage area of CONFIG_ENV_SIZE
3408 size used to hold a redundant copy of the environment data, so
3409 that there is a valid backup copy in case there is a power failure
3410 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3411 aligned to an erase block boundary.
3413 - CONFIG_ENV_RANGE (optional):
3415 Specifies the length of the region in which the environment
3416 can be written. This should be a multiple of the NAND device's
3417 block size. Specifying a range with more erase blocks than
3418 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3419 the range to be avoided.
3421 - CONFIG_ENV_OFFSET_OOB (optional):
3423 Enables support for dynamically retrieving the offset of the
3424 environment from block zero's out-of-band data. The
3425 "nand env.oob" command can be used to record this offset.
3426 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3427 using CONFIG_ENV_OFFSET_OOB.
3429 - CONFIG_NAND_ENV_DST
3431 Defines address in RAM to which the nand_spl code should copy the
3432 environment. If redundant environment is used, it will be copied to
3433 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3435 - CONFIG_SYS_SPI_INIT_OFFSET
3437 Defines offset to the initial SPI buffer area in DPRAM. The
3438 area is used at an early stage (ROM part) if the environment
3439 is configured to reside in the SPI EEPROM: We need a 520 byte
3440 scratch DPRAM area. It is used between the two initialization
3441 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3442 to be a good choice since it makes it far enough from the
3443 start of the data area as well as from the stack pointer.
3445 Please note that the environment is read-only until the monitor
3446 has been relocated to RAM and a RAM copy of the environment has been
3447 created; also, when using EEPROM you will have to use getenv_f()
3448 until then to read environment variables.
3450 The environment is protected by a CRC32 checksum. Before the monitor
3451 is relocated into RAM, as a result of a bad CRC you will be working
3452 with the compiled-in default environment - *silently*!!! [This is
3453 necessary, because the first environment variable we need is the
3454 "baudrate" setting for the console - if we have a bad CRC, we don't
3455 have any device yet where we could complain.]
3457 Note: once the monitor has been relocated, then it will complain if
3458 the default environment is used; a new CRC is computed as soon as you
3459 use the "saveenv" command to store a valid environment.
3461 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3462 Echo the inverted Ethernet link state to the fault LED.
3464 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3465 also needs to be defined.
3467 - CONFIG_SYS_FAULT_MII_ADDR:
3468 MII address of the PHY to check for the Ethernet link state.
3470 - CONFIG_NS16550_MIN_FUNCTIONS:
3471 Define this if you desire to only have use of the NS16550_init
3472 and NS16550_putc functions for the serial driver located at
3473 drivers/serial/ns16550.c. This option is useful for saving
3474 space for already greatly restricted images, including but not
3475 limited to NAND_SPL configurations.
3477 - CONFIG_DISPLAY_BOARDINFO
3478 Display information about the board that U-Boot is running on
3479 when U-Boot starts up. The board function checkboard() is called
3482 - CONFIG_DISPLAY_BOARDINFO_LATE
3483 Similar to the previous option, but display this information
3484 later, once stdio is running and output goes to the LCD, if
3487 Low Level (hardware related) configuration options:
3488 ---------------------------------------------------
3490 - CONFIG_SYS_CACHELINE_SIZE:
3491 Cache Line Size of the CPU.
3493 - CONFIG_SYS_DEFAULT_IMMR:
3494 Default address of the IMMR after system reset.
3496 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3497 and RPXsuper) to be able to adjust the position of
3498 the IMMR register after a reset.
3500 - CONFIG_SYS_CCSRBAR_DEFAULT:
3501 Default (power-on reset) physical address of CCSR on Freescale
3504 - CONFIG_SYS_CCSRBAR:
3505 Virtual address of CCSR. On a 32-bit build, this is typically
3506 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3508 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3509 for cross-platform code that uses that macro instead.
3511 - CONFIG_SYS_CCSRBAR_PHYS:
3512 Physical address of CCSR. CCSR can be relocated to a new
3513 physical address, if desired. In this case, this macro should
3514 be set to that address. Otherwise, it should be set to the
3515 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3516 is typically relocated on 36-bit builds. It is recommended
3517 that this macro be defined via the _HIGH and _LOW macros:
3519 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3520 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3522 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3523 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3524 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3525 used in assembly code, so it must not contain typecasts or
3526 integer size suffixes (e.g. "ULL").
3528 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3529 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3530 used in assembly code, so it must not contain typecasts or
3531 integer size suffixes (e.g. "ULL").
3533 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3534 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3535 forced to a value that ensures that CCSR is not relocated.
3537 - Floppy Disk Support:
3538 CONFIG_SYS_FDC_DRIVE_NUMBER
3540 the default drive number (default value 0)
3542 CONFIG_SYS_ISA_IO_STRIDE
3544 defines the spacing between FDC chipset registers
3547 CONFIG_SYS_ISA_IO_OFFSET
3549 defines the offset of register from address. It
3550 depends on which part of the data bus is connected to
3551 the FDC chipset. (default value 0)
3553 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3554 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3557 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3558 fdc_hw_init() is called at the beginning of the FDC
3559 setup. fdc_hw_init() must be provided by the board
3560 source code. It is used to make hardware dependant
3564 Most IDE controllers were designed to be connected with PCI
3565 interface. Only few of them were designed for AHB interface.
3566 When software is doing ATA command and data transfer to
3567 IDE devices through IDE-AHB controller, some additional
3568 registers accessing to these kind of IDE-AHB controller
3571 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3572 DO NOT CHANGE unless you know exactly what you're
3573 doing! (11-4) [MPC8xx/82xx systems only]
3575 - CONFIG_SYS_INIT_RAM_ADDR:
3577 Start address of memory area that can be used for
3578 initial data and stack; please note that this must be
3579 writable memory that is working WITHOUT special
3580 initialization, i. e. you CANNOT use normal RAM which
3581 will become available only after programming the
3582 memory controller and running certain initialization
3585 U-Boot uses the following memory types:
3586 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3587 - MPC824X: data cache
3588 - PPC4xx: data cache
3590 - CONFIG_SYS_GBL_DATA_OFFSET:
3592 Offset of the initial data structure in the memory
3593 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3594 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3595 data is located at the end of the available space
3596 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3597 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3598 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3599 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3602 On the MPC824X (or other systems that use the data
3603 cache for initial memory) the address chosen for
3604 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3605 point to an otherwise UNUSED address space between
3606 the top of RAM and the start of the PCI space.
3608 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3610 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3612 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3614 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3616 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3618 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3620 - CONFIG_SYS_OR_TIMING_SDRAM:
3623 - CONFIG_SYS_MAMR_PTA:
3624 periodic timer for refresh
3626 - CONFIG_SYS_DER: Debug Event Register (37-47)
3628 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3629 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3630 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3631 CONFIG_SYS_BR1_PRELIM:
3632 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3634 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3635 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3636 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3637 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3639 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3640 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3641 Machine Mode Register and Memory Periodic Timer
3642 Prescaler definitions (SDRAM timing)
3644 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3645 enable I2C microcode relocation patch (MPC8xx);
3646 define relocation offset in DPRAM [DSP2]
3648 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3649 enable SMC microcode relocation patch (MPC8xx);
3650 define relocation offset in DPRAM [SMC1]
3652 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3653 enable SPI microcode relocation patch (MPC8xx);
3654 define relocation offset in DPRAM [SCC4]
3656 - CONFIG_SYS_USE_OSCCLK:
3657 Use OSCM clock mode on MBX8xx board. Be careful,
3658 wrong setting might damage your board. Read
3659 doc/README.MBX before setting this variable!
3661 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3662 Offset of the bootmode word in DPRAM used by post
3663 (Power On Self Tests). This definition overrides
3664 #define'd default value in commproc.h resp.
3667 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3668 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3669 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3670 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3671 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3672 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3673 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3674 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3675 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3677 - CONFIG_PCI_DISABLE_PCIE:
3678 Disable PCI-Express on systems where it is supported but not
3681 - CONFIG_PCI_ENUM_ONLY
3682 Only scan through and get the devices on the busses.
3683 Don't do any setup work, presumably because someone or
3684 something has already done it, and we don't need to do it
3685 a second time. Useful for platforms that are pre-booted
3686 by coreboot or similar.
3689 Chip has SRIO or not
3692 Board has SRIO 1 port available
3695 Board has SRIO 2 port available
3697 - CONFIG_SYS_SRIOn_MEM_VIRT:
3698 Virtual Address of SRIO port 'n' memory region
3700 - CONFIG_SYS_SRIOn_MEM_PHYS:
3701 Physical Address of SRIO port 'n' memory region
3703 - CONFIG_SYS_SRIOn_MEM_SIZE:
3704 Size of SRIO port 'n' memory region
3706 - CONFIG_SYS_NDFC_16
3707 Defined to tell the NDFC that the NAND chip is using a
3710 - CONFIG_SYS_NDFC_EBC0_CFG
3711 Sets the EBC0_CFG register for the NDFC. If not defined
3712 a default value will be used.
3715 Get DDR timing information from an I2C EEPROM. Common
3716 with pluggable memory modules such as SODIMMs
3719 I2C address of the SPD EEPROM
3721 - CONFIG_SYS_SPD_BUS_NUM
3722 If SPD EEPROM is on an I2C bus other than the first
3723 one, specify here. Note that the value must resolve
3724 to something your driver can deal with.
3726 - CONFIG_SYS_DDR_RAW_TIMING
3727 Get DDR timing information from other than SPD. Common with
3728 soldered DDR chips onboard without SPD. DDR raw timing
3729 parameters are extracted from datasheet and hard-coded into
3730 header files or board specific files.
3732 - CONFIG_FSL_DDR_INTERACTIVE
3733 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3735 - CONFIG_SYS_83XX_DDR_USES_CS0
3736 Only for 83xx systems. If specified, then DDR should
3737 be configured using CS0 and CS1 instead of CS2 and CS3.
3739 - CONFIG_ETHER_ON_FEC[12]
3740 Define to enable FEC[12] on a 8xx series processor.
3742 - CONFIG_FEC[12]_PHY
3743 Define to the hardcoded PHY address which corresponds
3744 to the given FEC; i. e.
3745 #define CONFIG_FEC1_PHY 4
3746 means that the PHY with address 4 is connected to FEC1
3748 When set to -1, means to probe for first available.
3750 - CONFIG_FEC[12]_PHY_NORXERR
3751 The PHY does not have a RXERR line (RMII only).
3752 (so program the FEC to ignore it).
3755 Enable RMII mode for all FECs.
3756 Note that this is a global option, we can't
3757 have one FEC in standard MII mode and another in RMII mode.
3759 - CONFIG_CRC32_VERIFY
3760 Add a verify option to the crc32 command.
3763 => crc32 -v <address> <count> <crc32>
3765 Where address/count indicate a memory area
3766 and crc32 is the correct crc32 which the
3770 Add the "loopw" memory command. This only takes effect if
3771 the memory commands are activated globally (CONFIG_CMD_MEM).
3774 Add the "mdc" and "mwc" memory commands. These are cyclic
3779 This command will print 4 bytes (10,11,12,13) each 500 ms.
3781 => mwc.l 100 12345678 10
3782 This command will write 12345678 to address 100 all 10 ms.
3784 This only takes effect if the memory commands are activated
3785 globally (CONFIG_CMD_MEM).
3787 - CONFIG_SKIP_LOWLEVEL_INIT
3788 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3789 low level initializations (like setting up the memory
3790 controller) are omitted and/or U-Boot does not
3791 relocate itself into RAM.
3793 Normally this variable MUST NOT be defined. The only
3794 exception is when U-Boot is loaded (to RAM) by some
3795 other boot loader or by a debugger which performs
3796 these initializations itself.
3799 Modifies the behaviour of start.S when compiling a loader
3800 that is executed before the actual U-Boot. E.g. when
3801 compiling a NAND SPL.
3803 - CONFIG_USE_ARCH_MEMCPY
3804 CONFIG_USE_ARCH_MEMSET
3805 If these options are used a optimized version of memcpy/memset will
3806 be used if available. These functions may be faster under some
3807 conditions but may increase the binary size.
3809 - CONFIG_X86_NO_RESET_VECTOR
3810 If defined, the x86 reset vector code is excluded. You will need
3811 to do this when U-Boot is running from Coreboot.
3813 - CONFIG_X86_NO_REAL_MODE
3814 If defined, x86 real mode code is omitted. This assumes a
3815 32-bit environment where such code is not needed. You will
3816 need to do this when U-Boot is running from Coreboot.
3819 Freescale QE/FMAN Firmware Support:
3820 -----------------------------------
3822 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3823 loading of "firmware", which is encoded in the QE firmware binary format.
3824 This firmware often needs to be loaded during U-Boot booting, so macros
3825 are used to identify the storage device (NOR flash, SPI, etc) and the address
3828 - CONFIG_SYS_QE_FMAN_FW_ADDR
3829 The address in the storage device where the firmware is located. The
3830 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3833 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3834 The maximum possible size of the firmware. The firmware binary format
3835 has a field that specifies the actual size of the firmware, but it
3836 might not be possible to read any part of the firmware unless some
3837 local storage is allocated to hold the entire firmware first.
3839 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3840 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3841 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3842 virtual address in NOR flash.
3844 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3845 Specifies that QE/FMAN firmware is located in NAND flash.
3846 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3848 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3849 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3850 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3852 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3853 Specifies that QE/FMAN firmware is located on the primary SPI
3854 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3856 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3857 Specifies that QE/FMAN firmware is located in the remote (master)
3858 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3859 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3860 window->master inbound window->master LAW->the ucode address in
3861 master's memory space.
3863 Building the Software:
3864 ======================
3866 Building U-Boot has been tested in several native build environments
3867 and in many different cross environments. Of course we cannot support
3868 all possibly existing versions of cross development tools in all
3869 (potentially obsolete) versions. In case of tool chain problems we
3870 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3871 which is extensively used to build and test U-Boot.
3873 If you are not using a native environment, it is assumed that you
3874 have GNU cross compiling tools available in your path. In this case,
3875 you must set the environment variable CROSS_COMPILE in your shell.
3876 Note that no changes to the Makefile or any other source files are
3877 necessary. For example using the ELDK on a 4xx CPU, please enter:
3879 $ CROSS_COMPILE=ppc_4xx-
3880 $ export CROSS_COMPILE
3882 Note: If you wish to generate Windows versions of the utilities in
3883 the tools directory you can use the MinGW toolchain
3884 (http://www.mingw.org). Set your HOST tools to the MinGW
3885 toolchain and execute 'make tools'. For example:
3887 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3889 Binaries such as tools/mkimage.exe will be created which can
3890 be executed on computers running Windows.
3892 U-Boot is intended to be simple to build. After installing the
3893 sources you must configure U-Boot for one specific board type. This
3898 where "NAME_config" is the name of one of the existing configu-
3899 rations; see boards.cfg for supported names.
3901 Note: for some board special configuration names may exist; check if
3902 additional information is available from the board vendor; for
3903 instance, the TQM823L systems are available without (standard)
3904 or with LCD support. You can select such additional "features"
3905 when choosing the configuration, i. e.
3908 - will configure for a plain TQM823L, i. e. no LCD support
3910 make TQM823L_LCD_config
3911 - will configure for a TQM823L with U-Boot console on LCD
3916 Finally, type "make all", and you should get some working U-Boot
3917 images ready for download to / installation on your system:
3919 - "u-boot.bin" is a raw binary image
3920 - "u-boot" is an image in ELF binary format
3921 - "u-boot.srec" is in Motorola S-Record format
3923 By default the build is performed locally and the objects are saved
3924 in the source directory. One of the two methods can be used to change
3925 this behavior and build U-Boot to some external directory:
3927 1. Add O= to the make command line invocations:
3929 make O=/tmp/build distclean
3930 make O=/tmp/build NAME_config
3931 make O=/tmp/build all
3933 2. Set environment variable BUILD_DIR to point to the desired location:
3935 export BUILD_DIR=/tmp/build
3940 Note that the command line "O=" setting overrides the BUILD_DIR environment
3944 Please be aware that the Makefiles assume you are using GNU make, so
3945 for instance on NetBSD you might need to use "gmake" instead of
3949 If the system board that you have is not listed, then you will need
3950 to port U-Boot to your hardware platform. To do this, follow these
3953 1. Add a new configuration option for your board to the toplevel
3954 "boards.cfg" file, using the existing entries as examples.
3955 Follow the instructions there to keep the boards in order.
3956 2. Create a new directory to hold your board specific code. Add any
3957 files you need. In your board directory, you will need at least
3958 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3959 3. Create a new configuration file "include/configs/<board>.h" for
3961 3. If you're porting U-Boot to a new CPU, then also create a new
3962 directory to hold your CPU specific code. Add any files you need.
3963 4. Run "make <board>_config" with your new name.
3964 5. Type "make", and you should get a working "u-boot.srec" file
3965 to be installed on your target system.
3966 6. Debug and solve any problems that might arise.
3967 [Of course, this last step is much harder than it sounds.]
3970 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3971 ==============================================================
3973 If you have modified U-Boot sources (for instance added a new board
3974 or support for new devices, a new CPU, etc.) you are expected to
3975 provide feedback to the other developers. The feedback normally takes
3976 the form of a "patch", i. e. a context diff against a certain (latest
3977 official or latest in the git repository) version of U-Boot sources.
3979 But before you submit such a patch, please verify that your modifi-
3980 cation did not break existing code. At least make sure that *ALL* of
3981 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3982 just run the "MAKEALL" script, which will configure and build U-Boot
3983 for ALL supported system. Be warned, this will take a while. You can
3984 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3985 environment variable to the script, i. e. to use the ELDK cross tools
3988 CROSS_COMPILE=ppc_8xx- MAKEALL
3990 or to build on a native PowerPC system you can type
3992 CROSS_COMPILE=' ' MAKEALL
3994 When using the MAKEALL script, the default behaviour is to build
3995 U-Boot in the source directory. This location can be changed by
3996 setting the BUILD_DIR environment variable. Also, for each target
3997 built, the MAKEALL script saves two log files (<target>.ERR and
3998 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3999 location can be changed by setting the MAKEALL_LOGDIR environment
4000 variable. For example:
4002 export BUILD_DIR=/tmp/build
4003 export MAKEALL_LOGDIR=/tmp/log
4004 CROSS_COMPILE=ppc_8xx- MAKEALL
4006 With the above settings build objects are saved in the /tmp/build,
4007 log files are saved in the /tmp/log and the source tree remains clean
4008 during the whole build process.
4011 See also "U-Boot Porting Guide" below.
4014 Monitor Commands - Overview:
4015 ============================
4017 go - start application at address 'addr'
4018 run - run commands in an environment variable
4019 bootm - boot application image from memory
4020 bootp - boot image via network using BootP/TFTP protocol
4021 bootz - boot zImage from memory
4022 tftpboot- boot image via network using TFTP protocol
4023 and env variables "ipaddr" and "serverip"
4024 (and eventually "gatewayip")
4025 tftpput - upload a file via network using TFTP protocol
4026 rarpboot- boot image via network using RARP/TFTP protocol
4027 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4028 loads - load S-Record file over serial line
4029 loadb - load binary file over serial line (kermit mode)
4031 mm - memory modify (auto-incrementing)
4032 nm - memory modify (constant address)
4033 mw - memory write (fill)
4035 cmp - memory compare
4036 crc32 - checksum calculation
4037 i2c - I2C sub-system
4038 sspi - SPI utility commands
4039 base - print or set address offset
4040 printenv- print environment variables
4041 setenv - set environment variables
4042 saveenv - save environment variables to persistent storage
4043 protect - enable or disable FLASH write protection
4044 erase - erase FLASH memory
4045 flinfo - print FLASH memory information
4046 nand - NAND memory operations (see doc/README.nand)
4047 bdinfo - print Board Info structure
4048 iminfo - print header information for application image
4049 coninfo - print console devices and informations
4050 ide - IDE sub-system
4051 loop - infinite loop on address range
4052 loopw - infinite write loop on address range
4053 mtest - simple RAM test
4054 icache - enable or disable instruction cache
4055 dcache - enable or disable data cache
4056 reset - Perform RESET of the CPU
4057 echo - echo args to console
4058 version - print monitor version
4059 help - print online help
4060 ? - alias for 'help'
4063 Monitor Commands - Detailed Description:
4064 ========================================
4068 For now: just type "help <command>".
4071 Environment Variables:
4072 ======================
4074 U-Boot supports user configuration using Environment Variables which
4075 can be made persistent by saving to Flash memory.
4077 Environment Variables are set using "setenv", printed using
4078 "printenv", and saved to Flash using "saveenv". Using "setenv"
4079 without a value can be used to delete a variable from the
4080 environment. As long as you don't save the environment you are
4081 working with an in-memory copy. In case the Flash area containing the
4082 environment is erased by accident, a default environment is provided.
4084 Some configuration options can be set using Environment Variables.
4086 List of environment variables (most likely not complete):
4088 baudrate - see CONFIG_BAUDRATE
4090 bootdelay - see CONFIG_BOOTDELAY
4092 bootcmd - see CONFIG_BOOTCOMMAND
4094 bootargs - Boot arguments when booting an RTOS image
4096 bootfile - Name of the image to load with TFTP
4098 bootm_low - Memory range available for image processing in the bootm
4099 command can be restricted. This variable is given as
4100 a hexadecimal number and defines lowest address allowed
4101 for use by the bootm command. See also "bootm_size"
4102 environment variable. Address defined by "bootm_low" is
4103 also the base of the initial memory mapping for the Linux
4104 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4107 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4108 This variable is given as a hexadecimal number and it
4109 defines the size of the memory region starting at base
4110 address bootm_low that is accessible by the Linux kernel
4111 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4112 as the default value if it is defined, and bootm_size is
4115 bootm_size - Memory range available for image processing in the bootm
4116 command can be restricted. This variable is given as
4117 a hexadecimal number and defines the size of the region
4118 allowed for use by the bootm command. See also "bootm_low"
4119 environment variable.
4121 updatefile - Location of the software update file on a TFTP server, used
4122 by the automatic software update feature. Please refer to
4123 documentation in doc/README.update for more details.
4125 autoload - if set to "no" (any string beginning with 'n'),
4126 "bootp" will just load perform a lookup of the
4127 configuration from the BOOTP server, but not try to
4128 load any image using TFTP
4130 autostart - if set to "yes", an image loaded using the "bootp",
4131 "rarpboot", "tftpboot" or "diskboot" commands will
4132 be automatically started (by internally calling
4135 If set to "no", a standalone image passed to the
4136 "bootm" command will be copied to the load address
4137 (and eventually uncompressed), but NOT be started.
4138 This can be used to load and uncompress arbitrary
4141 fdt_high - if set this restricts the maximum address that the
4142 flattened device tree will be copied into upon boot.
4143 For example, if you have a system with 1 GB memory
4144 at physical address 0x10000000, while Linux kernel
4145 only recognizes the first 704 MB as low memory, you
4146 may need to set fdt_high as 0x3C000000 to have the
4147 device tree blob be copied to the maximum address
4148 of the 704 MB low memory, so that Linux kernel can
4149 access it during the boot procedure.
4151 If this is set to the special value 0xFFFFFFFF then
4152 the fdt will not be copied at all on boot. For this
4153 to work it must reside in writable memory, have
4154 sufficient padding on the end of it for u-boot to
4155 add the information it needs into it, and the memory
4156 must be accessible by the kernel.
4158 fdtcontroladdr- if set this is the address of the control flattened
4159 device tree used by U-Boot when CONFIG_OF_CONTROL is
4162 i2cfast - (PPC405GP|PPC405EP only)
4163 if set to 'y' configures Linux I2C driver for fast
4164 mode (400kHZ). This environment variable is used in
4165 initialization code. So, for changes to be effective
4166 it must be saved and board must be reset.
4168 initrd_high - restrict positioning of initrd images:
4169 If this variable is not set, initrd images will be
4170 copied to the highest possible address in RAM; this
4171 is usually what you want since it allows for
4172 maximum initrd size. If for some reason you want to
4173 make sure that the initrd image is loaded below the
4174 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4175 variable to a value of "no" or "off" or "0".
4176 Alternatively, you can set it to a maximum upper
4177 address to use (U-Boot will still check that it
4178 does not overwrite the U-Boot stack and data).
4180 For instance, when you have a system with 16 MB
4181 RAM, and want to reserve 4 MB from use by Linux,
4182 you can do this by adding "mem=12M" to the value of
4183 the "bootargs" variable. However, now you must make
4184 sure that the initrd image is placed in the first
4185 12 MB as well - this can be done with
4187 setenv initrd_high 00c00000
4189 If you set initrd_high to 0xFFFFFFFF, this is an
4190 indication to U-Boot that all addresses are legal
4191 for the Linux kernel, including addresses in flash
4192 memory. In this case U-Boot will NOT COPY the
4193 ramdisk at all. This may be useful to reduce the
4194 boot time on your system, but requires that this
4195 feature is supported by your Linux kernel.
4197 ipaddr - IP address; needed for tftpboot command
4199 loadaddr - Default load address for commands like "bootp",
4200 "rarpboot", "tftpboot", "loadb" or "diskboot"
4202 loads_echo - see CONFIG_LOADS_ECHO
4204 serverip - TFTP server IP address; needed for tftpboot command
4206 bootretry - see CONFIG_BOOT_RETRY_TIME
4208 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4210 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4212 ethprime - controls which interface is used first.
4214 ethact - controls which interface is currently active.
4215 For example you can do the following
4217 => setenv ethact FEC
4218 => ping 192.168.0.1 # traffic sent on FEC
4219 => setenv ethact SCC
4220 => ping 10.0.0.1 # traffic sent on SCC
4222 ethrotate - When set to "no" U-Boot does not go through all
4223 available network interfaces.
4224 It just stays at the currently selected interface.
4226 netretry - When set to "no" each network operation will
4227 either succeed or fail without retrying.
4228 When set to "once" the network operation will
4229 fail when all the available network interfaces
4230 are tried once without success.
4231 Useful on scripts which control the retry operation
4234 npe_ucode - set load address for the NPE microcode
4236 tftpsrcport - If this is set, the value is used for TFTP's
4239 tftpdstport - If this is set, the value is used for TFTP's UDP
4240 destination port instead of the Well Know Port 69.
4242 tftpblocksize - Block size to use for TFTP transfers; if not set,
4243 we use the TFTP server's default block size
4245 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4246 seconds, minimum value is 1000 = 1 second). Defines
4247 when a packet is considered to be lost so it has to
4248 be retransmitted. The default is 5000 = 5 seconds.
4249 Lowering this value may make downloads succeed
4250 faster in networks with high packet loss rates or
4251 with unreliable TFTP servers.
4253 vlan - When set to a value < 4095 the traffic over
4254 Ethernet is encapsulated/received over 802.1q
4257 The following image location variables contain the location of images
4258 used in booting. The "Image" column gives the role of the image and is
4259 not an environment variable name. The other columns are environment
4260 variable names. "File Name" gives the name of the file on a TFTP
4261 server, "RAM Address" gives the location in RAM the image will be
4262 loaded to, and "Flash Location" gives the image's address in NOR
4263 flash or offset in NAND flash.
4265 *Note* - these variables don't have to be defined for all boards, some
4266 boards currenlty use other variables for these purposes, and some
4267 boards use these variables for other purposes.
4269 Image File Name RAM Address Flash Location
4270 ----- --------- ----------- --------------
4271 u-boot u-boot u-boot_addr_r u-boot_addr
4272 Linux kernel bootfile kernel_addr_r kernel_addr
4273 device tree blob fdtfile fdt_addr_r fdt_addr
4274 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4276 The following environment variables may be used and automatically
4277 updated by the network boot commands ("bootp" and "rarpboot"),
4278 depending the information provided by your boot server:
4280 bootfile - see above
4281 dnsip - IP address of your Domain Name Server
4282 dnsip2 - IP address of your secondary Domain Name Server
4283 gatewayip - IP address of the Gateway (Router) to use
4284 hostname - Target hostname
4286 netmask - Subnet Mask
4287 rootpath - Pathname of the root filesystem on the NFS server
4288 serverip - see above
4291 There are two special Environment Variables:
4293 serial# - contains hardware identification information such
4294 as type string and/or serial number
4295 ethaddr - Ethernet address
4297 These variables can be set only once (usually during manufacturing of
4298 the board). U-Boot refuses to delete or overwrite these variables
4299 once they have been set once.
4302 Further special Environment Variables:
4304 ver - Contains the U-Boot version string as printed
4305 with the "version" command. This variable is
4306 readonly (see CONFIG_VERSION_VARIABLE).
4309 Please note that changes to some configuration parameters may take
4310 only effect after the next boot (yes, that's just like Windoze :-).
4313 Callback functions for environment variables:
4314 ---------------------------------------------
4316 For some environment variables, the behavior of u-boot needs to change
4317 when their values are changed. This functionailty allows functions to
4318 be associated with arbitrary variables. On creation, overwrite, or
4319 deletion, the callback will provide the opportunity for some side
4320 effect to happen or for the change to be rejected.
4322 The callbacks are named and associated with a function using the
4323 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4325 These callbacks are associated with variables in one of two ways. The
4326 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4327 in the board configuration to a string that defines a list of
4328 associations. The list must be in the following format:
4330 entry = variable_name[:callback_name]
4333 If the callback name is not specified, then the callback is deleted.
4334 Spaces are also allowed anywhere in the list.
4336 Callbacks can also be associated by defining the ".callbacks" variable
4337 with the same list format above. Any association in ".callbacks" will
4338 override any association in the static list. You can define
4339 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4340 ".callbacks" envirnoment variable in the default or embedded environment.
4343 Command Line Parsing:
4344 =====================
4346 There are two different command line parsers available with U-Boot:
4347 the old "simple" one, and the much more powerful "hush" shell:
4349 Old, simple command line parser:
4350 --------------------------------
4352 - supports environment variables (through setenv / saveenv commands)
4353 - several commands on one line, separated by ';'
4354 - variable substitution using "... ${name} ..." syntax
4355 - special characters ('$', ';') can be escaped by prefixing with '\',
4357 setenv bootcmd bootm \${address}
4358 - You can also escape text by enclosing in single apostrophes, for example:
4359 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4364 - similar to Bourne shell, with control structures like
4365 if...then...else...fi, for...do...done; while...do...done,
4366 until...do...done, ...
4367 - supports environment ("global") variables (through setenv / saveenv
4368 commands) and local shell variables (through standard shell syntax
4369 "name=value"); only environment variables can be used with "run"
4375 (1) If a command line (or an environment variable executed by a "run"
4376 command) contains several commands separated by semicolon, and
4377 one of these commands fails, then the remaining commands will be
4380 (2) If you execute several variables with one call to run (i. e.
4381 calling run with a list of variables as arguments), any failing
4382 command will cause "run" to terminate, i. e. the remaining
4383 variables are not executed.
4385 Note for Redundant Ethernet Interfaces:
4386 =======================================
4388 Some boards come with redundant Ethernet interfaces; U-Boot supports
4389 such configurations and is capable of automatic selection of a
4390 "working" interface when needed. MAC assignment works as follows:
4392 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4393 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4394 "eth1addr" (=>eth1), "eth2addr", ...
4396 If the network interface stores some valid MAC address (for instance
4397 in SROM), this is used as default address if there is NO correspon-
4398 ding setting in the environment; if the corresponding environment
4399 variable is set, this overrides the settings in the card; that means:
4401 o If the SROM has a valid MAC address, and there is no address in the
4402 environment, the SROM's address is used.
4404 o If there is no valid address in the SROM, and a definition in the
4405 environment exists, then the value from the environment variable is
4408 o If both the SROM and the environment contain a MAC address, and
4409 both addresses are the same, this MAC address is used.
4411 o If both the SROM and the environment contain a MAC address, and the
4412 addresses differ, the value from the environment is used and a
4415 o If neither SROM nor the environment contain a MAC address, an error
4418 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4419 will be programmed into hardware as part of the initialization process. This
4420 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4421 The naming convention is as follows:
4422 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4427 U-Boot is capable of booting (and performing other auxiliary operations on)
4428 images in two formats:
4430 New uImage format (FIT)
4431 -----------------------
4433 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4434 to Flattened Device Tree). It allows the use of images with multiple
4435 components (several kernels, ramdisks, etc.), with contents protected by
4436 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4442 Old image format is based on binary files which can be basically anything,
4443 preceded by a special header; see the definitions in include/image.h for
4444 details; basically, the header defines the following image properties:
4446 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4447 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4448 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4449 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4451 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4452 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4453 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4454 * Compression Type (uncompressed, gzip, bzip2)
4460 The header is marked by a special Magic Number, and both the header
4461 and the data portions of the image are secured against corruption by
4468 Although U-Boot should support any OS or standalone application
4469 easily, the main focus has always been on Linux during the design of
4472 U-Boot includes many features that so far have been part of some
4473 special "boot loader" code within the Linux kernel. Also, any
4474 "initrd" images to be used are no longer part of one big Linux image;
4475 instead, kernel and "initrd" are separate images. This implementation
4476 serves several purposes:
4478 - the same features can be used for other OS or standalone
4479 applications (for instance: using compressed images to reduce the
4480 Flash memory footprint)
4482 - it becomes much easier to port new Linux kernel versions because
4483 lots of low-level, hardware dependent stuff are done by U-Boot
4485 - the same Linux kernel image can now be used with different "initrd"
4486 images; of course this also means that different kernel images can
4487 be run with the same "initrd". This makes testing easier (you don't
4488 have to build a new "zImage.initrd" Linux image when you just
4489 change a file in your "initrd"). Also, a field-upgrade of the
4490 software is easier now.
4496 Porting Linux to U-Boot based systems:
4497 ---------------------------------------
4499 U-Boot cannot save you from doing all the necessary modifications to
4500 configure the Linux device drivers for use with your target hardware
4501 (no, we don't intend to provide a full virtual machine interface to
4504 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4506 Just make sure your machine specific header file (for instance
4507 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4508 Information structure as we define in include/asm-<arch>/u-boot.h,
4509 and make sure that your definition of IMAP_ADDR uses the same value
4510 as your U-Boot configuration in CONFIG_SYS_IMMR.
4513 Configuring the Linux kernel:
4514 -----------------------------
4516 No specific requirements for U-Boot. Make sure you have some root
4517 device (initial ramdisk, NFS) for your target system.
4520 Building a Linux Image:
4521 -----------------------
4523 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4524 not used. If you use recent kernel source, a new build target
4525 "uImage" will exist which automatically builds an image usable by
4526 U-Boot. Most older kernels also have support for a "pImage" target,
4527 which was introduced for our predecessor project PPCBoot and uses a
4528 100% compatible format.
4537 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4538 encapsulate a compressed Linux kernel image with header information,
4539 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4541 * build a standard "vmlinux" kernel image (in ELF binary format):
4543 * convert the kernel into a raw binary image:
4545 ${CROSS_COMPILE}-objcopy -O binary \
4546 -R .note -R .comment \
4547 -S vmlinux linux.bin
4549 * compress the binary image:
4553 * package compressed binary image for U-Boot:
4555 mkimage -A ppc -O linux -T kernel -C gzip \
4556 -a 0 -e 0 -n "Linux Kernel Image" \
4557 -d linux.bin.gz uImage
4560 The "mkimage" tool can also be used to create ramdisk images for use
4561 with U-Boot, either separated from the Linux kernel image, or
4562 combined into one file. "mkimage" encapsulates the images with a 64
4563 byte header containing information about target architecture,
4564 operating system, image type, compression method, entry points, time
4565 stamp, CRC32 checksums, etc.
4567 "mkimage" can be called in two ways: to verify existing images and
4568 print the header information, or to build new images.
4570 In the first form (with "-l" option) mkimage lists the information
4571 contained in the header of an existing U-Boot image; this includes
4572 checksum verification:
4574 tools/mkimage -l image
4575 -l ==> list image header information
4577 The second form (with "-d" option) is used to build a U-Boot image
4578 from a "data file" which is used as image payload:
4580 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4581 -n name -d data_file image
4582 -A ==> set architecture to 'arch'
4583 -O ==> set operating system to 'os'
4584 -T ==> set image type to 'type'
4585 -C ==> set compression type 'comp'
4586 -a ==> set load address to 'addr' (hex)
4587 -e ==> set entry point to 'ep' (hex)
4588 -n ==> set image name to 'name'
4589 -d ==> use image data from 'datafile'
4591 Right now, all Linux kernels for PowerPC systems use the same load
4592 address (0x00000000), but the entry point address depends on the
4595 - 2.2.x kernels have the entry point at 0x0000000C,
4596 - 2.3.x and later kernels have the entry point at 0x00000000.
4598 So a typical call to build a U-Boot image would read:
4600 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4601 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4602 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4603 > examples/uImage.TQM850L
4604 Image Name: 2.4.4 kernel for TQM850L
4605 Created: Wed Jul 19 02:34:59 2000
4606 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4607 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4608 Load Address: 0x00000000
4609 Entry Point: 0x00000000
4611 To verify the contents of the image (or check for corruption):
4613 -> tools/mkimage -l examples/uImage.TQM850L
4614 Image Name: 2.4.4 kernel for TQM850L
4615 Created: Wed Jul 19 02:34:59 2000
4616 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4617 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4618 Load Address: 0x00000000
4619 Entry Point: 0x00000000
4621 NOTE: for embedded systems where boot time is critical you can trade
4622 speed for memory and install an UNCOMPRESSED image instead: this
4623 needs more space in Flash, but boots much faster since it does not
4624 need to be uncompressed:
4626 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4627 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4628 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4629 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4630 > examples/uImage.TQM850L-uncompressed
4631 Image Name: 2.4.4 kernel for TQM850L
4632 Created: Wed Jul 19 02:34:59 2000
4633 Image Type: PowerPC Linux Kernel Image (uncompressed)
4634 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4635 Load Address: 0x00000000
4636 Entry Point: 0x00000000
4639 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4640 when your kernel is intended to use an initial ramdisk:
4642 -> tools/mkimage -n 'Simple Ramdisk Image' \
4643 > -A ppc -O linux -T ramdisk -C gzip \
4644 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4645 Image Name: Simple Ramdisk Image
4646 Created: Wed Jan 12 14:01:50 2000
4647 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4648 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4649 Load Address: 0x00000000
4650 Entry Point: 0x00000000
4653 Installing a Linux Image:
4654 -------------------------
4656 To downloading a U-Boot image over the serial (console) interface,
4657 you must convert the image to S-Record format:
4659 objcopy -I binary -O srec examples/image examples/image.srec
4661 The 'objcopy' does not understand the information in the U-Boot
4662 image header, so the resulting S-Record file will be relative to
4663 address 0x00000000. To load it to a given address, you need to
4664 specify the target address as 'offset' parameter with the 'loads'
4667 Example: install the image to address 0x40100000 (which on the
4668 TQM8xxL is in the first Flash bank):
4670 => erase 40100000 401FFFFF
4676 ## Ready for S-Record download ...
4677 ~>examples/image.srec
4678 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4680 15989 15990 15991 15992
4681 [file transfer complete]
4683 ## Start Addr = 0x00000000
4686 You can check the success of the download using the 'iminfo' command;
4687 this includes a checksum verification so you can be sure no data
4688 corruption happened:
4692 ## Checking Image at 40100000 ...
4693 Image Name: 2.2.13 for initrd on TQM850L
4694 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4695 Data Size: 335725 Bytes = 327 kB = 0 MB
4696 Load Address: 00000000
4697 Entry Point: 0000000c
4698 Verifying Checksum ... OK
4704 The "bootm" command is used to boot an application that is stored in
4705 memory (RAM or Flash). In case of a Linux kernel image, the contents
4706 of the "bootargs" environment variable is passed to the kernel as
4707 parameters. You can check and modify this variable using the
4708 "printenv" and "setenv" commands:
4711 => printenv bootargs
4712 bootargs=root=/dev/ram
4714 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4716 => printenv bootargs
4717 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4720 ## Booting Linux kernel at 40020000 ...
4721 Image Name: 2.2.13 for NFS on TQM850L
4722 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4723 Data Size: 381681 Bytes = 372 kB = 0 MB
4724 Load Address: 00000000
4725 Entry Point: 0000000c
4726 Verifying Checksum ... OK
4727 Uncompressing Kernel Image ... OK
4728 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
4729 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4730 time_init: decrementer frequency = 187500000/60
4731 Calibrating delay loop... 49.77 BogoMIPS
4732 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4735 If you want to boot a Linux kernel with initial RAM disk, you pass
4736 the memory addresses of both the kernel and the initrd image (PPBCOOT
4737 format!) to the "bootm" command:
4739 => imi 40100000 40200000
4741 ## Checking Image at 40100000 ...
4742 Image Name: 2.2.13 for initrd on TQM850L
4743 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4744 Data Size: 335725 Bytes = 327 kB = 0 MB
4745 Load Address: 00000000
4746 Entry Point: 0000000c
4747 Verifying Checksum ... OK
4749 ## Checking Image at 40200000 ...
4750 Image Name: Simple Ramdisk Image
4751 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4752 Data Size: 566530 Bytes = 553 kB = 0 MB
4753 Load Address: 00000000
4754 Entry Point: 00000000
4755 Verifying Checksum ... OK
4757 => bootm 40100000 40200000
4758 ## Booting Linux kernel at 40100000 ...
4759 Image Name: 2.2.13 for initrd on TQM850L
4760 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4761 Data Size: 335725 Bytes = 327 kB = 0 MB
4762 Load Address: 00000000
4763 Entry Point: 0000000c
4764 Verifying Checksum ... OK
4765 Uncompressing Kernel Image ... OK
4766 ## Loading RAMDisk Image at 40200000 ...
4767 Image Name: Simple Ramdisk Image
4768 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4769 Data Size: 566530 Bytes = 553 kB = 0 MB
4770 Load Address: 00000000
4771 Entry Point: 00000000
4772 Verifying Checksum ... OK
4773 Loading Ramdisk ... OK
4774 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
4775 Boot arguments: root=/dev/ram
4776 time_init: decrementer frequency = 187500000/60
4777 Calibrating delay loop... 49.77 BogoMIPS
4779 RAMDISK: Compressed image found at block 0
4780 VFS: Mounted root (ext2 filesystem).
4784 Boot Linux and pass a flat device tree:
4787 First, U-Boot must be compiled with the appropriate defines. See the section
4788 titled "Linux Kernel Interface" above for a more in depth explanation. The
4789 following is an example of how to start a kernel and pass an updated
4795 oft=oftrees/mpc8540ads.dtb
4796 => tftp $oftaddr $oft
4797 Speed: 1000, full duplex
4799 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4800 Filename 'oftrees/mpc8540ads.dtb'.
4801 Load address: 0x300000
4804 Bytes transferred = 4106 (100a hex)
4805 => tftp $loadaddr $bootfile
4806 Speed: 1000, full duplex
4808 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4810 Load address: 0x200000
4811 Loading:############
4813 Bytes transferred = 1029407 (fb51f hex)
4818 => bootm $loadaddr - $oftaddr
4819 ## Booting image at 00200000 ...
4820 Image Name: Linux-2.6.17-dirty
4821 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4822 Data Size: 1029343 Bytes = 1005.2 kB
4823 Load Address: 00000000
4824 Entry Point: 00000000
4825 Verifying Checksum ... OK
4826 Uncompressing Kernel Image ... OK
4827 Booting using flat device tree at 0x300000
4828 Using MPC85xx ADS machine description
4829 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4833 More About U-Boot Image Types:
4834 ------------------------------
4836 U-Boot supports the following image types:
4838 "Standalone Programs" are directly runnable in the environment
4839 provided by U-Boot; it is expected that (if they behave
4840 well) you can continue to work in U-Boot after return from
4841 the Standalone Program.
4842 "OS Kernel Images" are usually images of some Embedded OS which
4843 will take over control completely. Usually these programs
4844 will install their own set of exception handlers, device
4845 drivers, set up the MMU, etc. - this means, that you cannot
4846 expect to re-enter U-Boot except by resetting the CPU.
4847 "RAMDisk Images" are more or less just data blocks, and their
4848 parameters (address, size) are passed to an OS kernel that is
4850 "Multi-File Images" contain several images, typically an OS
4851 (Linux) kernel image and one or more data images like
4852 RAMDisks. This construct is useful for instance when you want
4853 to boot over the network using BOOTP etc., where the boot
4854 server provides just a single image file, but you want to get
4855 for instance an OS kernel and a RAMDisk image.
4857 "Multi-File Images" start with a list of image sizes, each
4858 image size (in bytes) specified by an "uint32_t" in network
4859 byte order. This list is terminated by an "(uint32_t)0".
4860 Immediately after the terminating 0 follow the images, one by
4861 one, all aligned on "uint32_t" boundaries (size rounded up to
4862 a multiple of 4 bytes).
4864 "Firmware Images" are binary images containing firmware (like
4865 U-Boot or FPGA images) which usually will be programmed to
4868 "Script files" are command sequences that will be executed by
4869 U-Boot's command interpreter; this feature is especially
4870 useful when you configure U-Boot to use a real shell (hush)
4871 as command interpreter.
4873 Booting the Linux zImage:
4874 -------------------------
4876 On some platforms, it's possible to boot Linux zImage. This is done
4877 using the "bootz" command. The syntax of "bootz" command is the same
4878 as the syntax of "bootm" command.
4880 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4881 kernel with raw initrd images. The syntax is slightly different, the
4882 address of the initrd must be augmented by it's size, in the following
4883 format: "<initrd addres>:<initrd size>".
4889 One of the features of U-Boot is that you can dynamically load and
4890 run "standalone" applications, which can use some resources of
4891 U-Boot like console I/O functions or interrupt services.
4893 Two simple examples are included with the sources:
4898 'examples/hello_world.c' contains a small "Hello World" Demo
4899 application; it is automatically compiled when you build U-Boot.
4900 It's configured to run at address 0x00040004, so you can play with it
4904 ## Ready for S-Record download ...
4905 ~>examples/hello_world.srec
4906 1 2 3 4 5 6 7 8 9 10 11 ...
4907 [file transfer complete]
4909 ## Start Addr = 0x00040004
4911 => go 40004 Hello World! This is a test.
4912 ## Starting application at 0x00040004 ...
4923 Hit any key to exit ...
4925 ## Application terminated, rc = 0x0
4927 Another example, which demonstrates how to register a CPM interrupt
4928 handler with the U-Boot code, can be found in 'examples/timer.c'.
4929 Here, a CPM timer is set up to generate an interrupt every second.
4930 The interrupt service routine is trivial, just printing a '.'
4931 character, but this is just a demo program. The application can be
4932 controlled by the following keys:
4934 ? - print current values og the CPM Timer registers
4935 b - enable interrupts and start timer
4936 e - stop timer and disable interrupts
4937 q - quit application
4940 ## Ready for S-Record download ...
4941 ~>examples/timer.srec
4942 1 2 3 4 5 6 7 8 9 10 11 ...
4943 [file transfer complete]
4945 ## Start Addr = 0x00040004
4948 ## Starting application at 0x00040004 ...
4951 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4954 [q, b, e, ?] Set interval 1000000 us
4957 [q, b, e, ?] ........
4958 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4961 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4964 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4967 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4969 [q, b, e, ?] ...Stopping timer
4971 [q, b, e, ?] ## Application terminated, rc = 0x0
4977 Over time, many people have reported problems when trying to use the
4978 "minicom" terminal emulation program for serial download. I (wd)
4979 consider minicom to be broken, and recommend not to use it. Under
4980 Unix, I recommend to use C-Kermit for general purpose use (and
4981 especially for kermit binary protocol download ("loadb" command), and
4982 use "cu" for S-Record download ("loads" command). See
4983 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4984 for help with kermit.
4987 Nevertheless, if you absolutely want to use it try adding this
4988 configuration to your "File transfer protocols" section:
4990 Name Program Name U/D FullScr IO-Red. Multi
4991 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4992 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4998 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4999 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5001 Building requires a cross environment; it is known to work on
5002 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5003 need gmake since the Makefiles are not compatible with BSD make).
5004 Note that the cross-powerpc package does not install include files;
5005 attempting to build U-Boot will fail because <machine/ansi.h> is
5006 missing. This file has to be installed and patched manually:
5008 # cd /usr/pkg/cross/powerpc-netbsd/include
5010 # ln -s powerpc machine
5011 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5012 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5014 Native builds *don't* work due to incompatibilities between native
5015 and U-Boot include files.
5017 Booting assumes that (the first part of) the image booted is a
5018 stage-2 loader which in turn loads and then invokes the kernel
5019 proper. Loader sources will eventually appear in the NetBSD source
5020 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5021 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5024 Implementation Internals:
5025 =========================
5027 The following is not intended to be a complete description of every
5028 implementation detail. However, it should help to understand the
5029 inner workings of U-Boot and make it easier to port it to custom
5033 Initial Stack, Global Data:
5034 ---------------------------
5036 The implementation of U-Boot is complicated by the fact that U-Boot
5037 starts running out of ROM (flash memory), usually without access to
5038 system RAM (because the memory controller is not initialized yet).
5039 This means that we don't have writable Data or BSS segments, and BSS
5040 is not initialized as zero. To be able to get a C environment working
5041 at all, we have to allocate at least a minimal stack. Implementation
5042 options for this are defined and restricted by the CPU used: Some CPU
5043 models provide on-chip memory (like the IMMR area on MPC8xx and
5044 MPC826x processors), on others (parts of) the data cache can be
5045 locked as (mis-) used as memory, etc.
5047 Chris Hallinan posted a good summary of these issues to the
5048 U-Boot mailing list:
5050 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5051 From: "Chris Hallinan" <clh@net1plus.com>
5052 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5055 Correct me if I'm wrong, folks, but the way I understand it
5056 is this: Using DCACHE as initial RAM for Stack, etc, does not
5057 require any physical RAM backing up the cache. The cleverness
5058 is that the cache is being used as a temporary supply of
5059 necessary storage before the SDRAM controller is setup. It's
5060 beyond the scope of this list to explain the details, but you
5061 can see how this works by studying the cache architecture and
5062 operation in the architecture and processor-specific manuals.
5064 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5065 is another option for the system designer to use as an
5066 initial stack/RAM area prior to SDRAM being available. Either
5067 option should work for you. Using CS 4 should be fine if your
5068 board designers haven't used it for something that would
5069 cause you grief during the initial boot! It is frequently not
5072 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5073 with your processor/board/system design. The default value
5074 you will find in any recent u-boot distribution in
5075 walnut.h should work for you. I'd set it to a value larger
5076 than your SDRAM module. If you have a 64MB SDRAM module, set
5077 it above 400_0000. Just make sure your board has no resources
5078 that are supposed to respond to that address! That code in
5079 start.S has been around a while and should work as is when
5080 you get the config right.
5085 It is essential to remember this, since it has some impact on the C
5086 code for the initialization procedures:
5088 * Initialized global data (data segment) is read-only. Do not attempt
5091 * Do not use any uninitialized global data (or implicitely initialized
5092 as zero data - BSS segment) at all - this is undefined, initiali-
5093 zation is performed later (when relocating to RAM).
5095 * Stack space is very limited. Avoid big data buffers or things like
5098 Having only the stack as writable memory limits means we cannot use
5099 normal global data to share information beween the code. But it
5100 turned out that the implementation of U-Boot can be greatly
5101 simplified by making a global data structure (gd_t) available to all
5102 functions. We could pass a pointer to this data as argument to _all_
5103 functions, but this would bloat the code. Instead we use a feature of
5104 the GCC compiler (Global Register Variables) to share the data: we
5105 place a pointer (gd) to the global data into a register which we
5106 reserve for this purpose.
5108 When choosing a register for such a purpose we are restricted by the
5109 relevant (E)ABI specifications for the current architecture, and by
5110 GCC's implementation.
5112 For PowerPC, the following registers have specific use:
5114 R2: reserved for system use
5115 R3-R4: parameter passing and return values
5116 R5-R10: parameter passing
5117 R13: small data area pointer
5121 (U-Boot also uses R12 as internal GOT pointer. r12
5122 is a volatile register so r12 needs to be reset when
5123 going back and forth between asm and C)
5125 ==> U-Boot will use R2 to hold a pointer to the global data
5127 Note: on PPC, we could use a static initializer (since the
5128 address of the global data structure is known at compile time),
5129 but it turned out that reserving a register results in somewhat
5130 smaller code - although the code savings are not that big (on
5131 average for all boards 752 bytes for the whole U-Boot image,
5132 624 text + 127 data).
5134 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5135 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5137 ==> U-Boot will use P3 to hold a pointer to the global data
5139 On ARM, the following registers are used:
5141 R0: function argument word/integer result
5142 R1-R3: function argument word
5144 R10: stack limit (used only if stack checking if enabled)
5145 R11: argument (frame) pointer
5146 R12: temporary workspace
5149 R15: program counter
5151 ==> U-Boot will use R8 to hold a pointer to the global data
5153 On Nios II, the ABI is documented here:
5154 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5156 ==> U-Boot will use gp to hold a pointer to the global data
5158 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5159 to access small data sections, so gp is free.
5161 On NDS32, the following registers are used:
5163 R0-R1: argument/return
5165 R15: temporary register for assembler
5166 R16: trampoline register
5167 R28: frame pointer (FP)
5168 R29: global pointer (GP)
5169 R30: link register (LP)
5170 R31: stack pointer (SP)
5171 PC: program counter (PC)
5173 ==> U-Boot will use R10 to hold a pointer to the global data
5175 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5176 or current versions of GCC may "optimize" the code too much.
5181 U-Boot runs in system state and uses physical addresses, i.e. the
5182 MMU is not used either for address mapping nor for memory protection.
5184 The available memory is mapped to fixed addresses using the memory
5185 controller. In this process, a contiguous block is formed for each
5186 memory type (Flash, SDRAM, SRAM), even when it consists of several
5187 physical memory banks.
5189 U-Boot is installed in the first 128 kB of the first Flash bank (on
5190 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5191 booting and sizing and initializing DRAM, the code relocates itself
5192 to the upper end of DRAM. Immediately below the U-Boot code some
5193 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5194 configuration setting]. Below that, a structure with global Board
5195 Info data is placed, followed by the stack (growing downward).
5197 Additionally, some exception handler code is copied to the low 8 kB
5198 of DRAM (0x00000000 ... 0x00001FFF).
5200 So a typical memory configuration with 16 MB of DRAM could look like
5203 0x0000 0000 Exception Vector code
5206 0x0000 2000 Free for Application Use
5212 0x00FB FF20 Monitor Stack (Growing downward)
5213 0x00FB FFAC Board Info Data and permanent copy of global data
5214 0x00FC 0000 Malloc Arena
5217 0x00FE 0000 RAM Copy of Monitor Code
5218 ... eventually: LCD or video framebuffer
5219 ... eventually: pRAM (Protected RAM - unchanged by reset)
5220 0x00FF FFFF [End of RAM]
5223 System Initialization:
5224 ----------------------
5226 In the reset configuration, U-Boot starts at the reset entry point
5227 (on most PowerPC systems at address 0x00000100). Because of the reset
5228 configuration for CS0# this is a mirror of the onboard Flash memory.
5229 To be able to re-map memory U-Boot then jumps to its link address.
5230 To be able to implement the initialization code in C, a (small!)
5231 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5232 which provide such a feature like MPC8xx or MPC8260), or in a locked
5233 part of the data cache. After that, U-Boot initializes the CPU core,
5234 the caches and the SIU.
5236 Next, all (potentially) available memory banks are mapped using a
5237 preliminary mapping. For example, we put them on 512 MB boundaries
5238 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5239 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5240 programmed for SDRAM access. Using the temporary configuration, a
5241 simple memory test is run that determines the size of the SDRAM
5244 When there is more than one SDRAM bank, and the banks are of
5245 different size, the largest is mapped first. For equal size, the first
5246 bank (CS2#) is mapped first. The first mapping is always for address
5247 0x00000000, with any additional banks following immediately to create
5248 contiguous memory starting from 0.
5250 Then, the monitor installs itself at the upper end of the SDRAM area
5251 and allocates memory for use by malloc() and for the global Board
5252 Info data; also, the exception vector code is copied to the low RAM
5253 pages, and the final stack is set up.
5255 Only after this relocation will you have a "normal" C environment;
5256 until that you are restricted in several ways, mostly because you are
5257 running from ROM, and because the code will have to be relocated to a
5261 U-Boot Porting Guide:
5262 ----------------------
5264 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5268 int main(int argc, char *argv[])
5270 sighandler_t no_more_time;
5272 signal(SIGALRM, no_more_time);
5273 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5275 if (available_money > available_manpower) {
5276 Pay consultant to port U-Boot;
5280 Download latest U-Boot source;
5282 Subscribe to u-boot mailing list;
5285 email("Hi, I am new to U-Boot, how do I get started?");
5288 Read the README file in the top level directory;
5289 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5290 Read applicable doc/*.README;
5291 Read the source, Luke;
5292 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5295 if (available_money > toLocalCurrency ($2500))
5298 Add a lot of aggravation and time;
5300 if (a similar board exists) { /* hopefully... */
5301 cp -a board/<similar> board/<myboard>
5302 cp include/configs/<similar>.h include/configs/<myboard>.h
5304 Create your own board support subdirectory;
5305 Create your own board include/configs/<myboard>.h file;
5307 Edit new board/<myboard> files
5308 Edit new include/configs/<myboard>.h
5313 Add / modify source code;
5317 email("Hi, I am having problems...");
5319 Send patch file to the U-Boot email list;
5320 if (reasonable critiques)
5321 Incorporate improvements from email list code review;
5323 Defend code as written;
5329 void no_more_time (int sig)
5338 All contributions to U-Boot should conform to the Linux kernel
5339 coding style; see the file "Documentation/CodingStyle" and the script
5340 "scripts/Lindent" in your Linux kernel source directory.
5342 Source files originating from a different project (for example the
5343 MTD subsystem) are generally exempt from these guidelines and are not
5344 reformated to ease subsequent migration to newer versions of those
5347 Please note that U-Boot is implemented in C (and to some small parts in
5348 Assembler); no C++ is used, so please do not use C++ style comments (//)
5351 Please also stick to the following formatting rules:
5352 - remove any trailing white space
5353 - use TAB characters for indentation and vertical alignment, not spaces
5354 - make sure NOT to use DOS '\r\n' line feeds
5355 - do not add more than 2 consecutive empty lines to source files
5356 - do not add trailing empty lines to source files
5358 Submissions which do not conform to the standards may be returned
5359 with a request to reformat the changes.
5365 Since the number of patches for U-Boot is growing, we need to
5366 establish some rules. Submissions which do not conform to these rules
5367 may be rejected, even when they contain important and valuable stuff.
5369 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5371 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5372 see http://lists.denx.de/mailman/listinfo/u-boot
5374 When you send a patch, please include the following information with
5377 * For bug fixes: a description of the bug and how your patch fixes
5378 this bug. Please try to include a way of demonstrating that the
5379 patch actually fixes something.
5381 * For new features: a description of the feature and your
5384 * A CHANGELOG entry as plaintext (separate from the patch)
5386 * For major contributions, your entry to the CREDITS file
5388 * When you add support for a new board, don't forget to add this
5389 board to the MAINTAINERS file, too.
5391 * If your patch adds new configuration options, don't forget to
5392 document these in the README file.
5394 * The patch itself. If you are using git (which is *strongly*
5395 recommended) you can easily generate the patch using the
5396 "git format-patch". If you then use "git send-email" to send it to
5397 the U-Boot mailing list, you will avoid most of the common problems
5398 with some other mail clients.
5400 If you cannot use git, use "diff -purN OLD NEW". If your version of
5401 diff does not support these options, then get the latest version of
5404 The current directory when running this command shall be the parent
5405 directory of the U-Boot source tree (i. e. please make sure that
5406 your patch includes sufficient directory information for the
5409 We prefer patches as plain text. MIME attachments are discouraged,
5410 and compressed attachments must not be used.
5412 * If one logical set of modifications affects or creates several
5413 files, all these changes shall be submitted in a SINGLE patch file.
5415 * Changesets that contain different, unrelated modifications shall be
5416 submitted as SEPARATE patches, one patch per changeset.
5421 * Before sending the patch, run the MAKEALL script on your patched
5422 source tree and make sure that no errors or warnings are reported
5423 for any of the boards.
5425 * Keep your modifications to the necessary minimum: A patch
5426 containing several unrelated changes or arbitrary reformats will be
5427 returned with a request to re-formatting / split it.
5429 * If you modify existing code, make sure that your new code does not
5430 add to the memory footprint of the code ;-) Small is beautiful!
5431 When adding new features, these should compile conditionally only
5432 (using #ifdef), and the resulting code with the new feature
5433 disabled must not need more memory than the old code without your
5436 * Remember that there is a size limit of 100 kB per message on the
5437 u-boot mailing list. Bigger patches will be moderated. If they are
5438 reasonable and not too big, they will be acknowledged. But patches
5439 bigger than the size limit should be avoided.
projects / oweals / u-boot.git / blob