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.
621 Depending on board, define exactly one serial port
622 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
623 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
624 console by defining CONFIG_8xx_CONS_NONE
626 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
627 port routines must be defined elsewhere
628 (i.e. serial_init(), serial_getc(), ...)
631 Enables console device for a color framebuffer. Needs following
632 defines (cf. smiLynxEM, i8042)
633 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
635 VIDEO_HW_RECTFILL graphic chip supports
638 VIDEO_HW_BITBLT graphic chip supports
639 bit-blit (cf. smiLynxEM)
640 VIDEO_VISIBLE_COLS visible pixel columns
642 VIDEO_VISIBLE_ROWS visible pixel rows
643 VIDEO_PIXEL_SIZE bytes per pixel
644 VIDEO_DATA_FORMAT graphic data format
645 (0-5, cf. cfb_console.c)
646 VIDEO_FB_ADRS framebuffer address
647 VIDEO_KBD_INIT_FCT keyboard int fct
648 (i.e. i8042_kbd_init())
649 VIDEO_TSTC_FCT test char fct
651 VIDEO_GETC_FCT get char fct
653 CONFIG_CONSOLE_CURSOR cursor drawing on/off
654 (requires blink timer
656 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
657 CONFIG_CONSOLE_TIME display time/date info in
659 (requires CONFIG_CMD_DATE)
660 CONFIG_VIDEO_LOGO display Linux logo in
662 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
663 linux_logo.h for logo.
664 Requires CONFIG_VIDEO_LOGO
665 CONFIG_CONSOLE_EXTRA_INFO
666 additional board info beside
669 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
670 a limited number of ANSI escape sequences (cursor control,
671 erase functions and limited graphics rendition control).
673 When CONFIG_CFB_CONSOLE is defined, video console is
674 default i/o. Serial console can be forced with
675 environment 'console=serial'.
677 When CONFIG_SILENT_CONSOLE is defined, all console
678 messages (by U-Boot and Linux!) can be silenced with
679 the "silent" environment variable. See
680 doc/README.silent for more information.
683 CONFIG_BAUDRATE - in bps
684 Select one of the baudrates listed in
685 CONFIG_SYS_BAUDRATE_TABLE, see below.
686 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
688 - Console Rx buffer length
689 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
690 the maximum receive buffer length for the SMC.
691 This option is actual only for 82xx and 8xx possible.
692 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
693 must be defined, to setup the maximum idle timeout for
696 - Pre-Console Buffer:
697 Prior to the console being initialised (i.e. serial UART
698 initialised etc) all console output is silently discarded.
699 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
700 buffer any console messages prior to the console being
701 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
702 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
703 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
704 bytes are output before the console is initialised, the
705 earlier bytes are discarded.
707 'Sane' compilers will generate smaller code if
708 CONFIG_PRE_CON_BUF_SZ is a power of 2
710 - Safe printf() functions
711 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
712 the printf() functions. These are defined in
713 include/vsprintf.h and include snprintf(), vsnprintf() and
714 so on. Code size increase is approximately 300-500 bytes.
715 If this option is not given then these functions will
716 silently discard their buffer size argument - this means
717 you are not getting any overflow checking in this case.
719 - Boot Delay: CONFIG_BOOTDELAY - in seconds
720 Delay before automatically booting the default image;
721 set to -1 to disable autoboot.
722 set to -2 to autoboot with no delay and not check for abort
723 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
725 See doc/README.autoboot for these options that
726 work with CONFIG_BOOTDELAY. None are required.
727 CONFIG_BOOT_RETRY_TIME
728 CONFIG_BOOT_RETRY_MIN
729 CONFIG_AUTOBOOT_KEYED
730 CONFIG_AUTOBOOT_PROMPT
731 CONFIG_AUTOBOOT_DELAY_STR
732 CONFIG_AUTOBOOT_STOP_STR
733 CONFIG_AUTOBOOT_DELAY_STR2
734 CONFIG_AUTOBOOT_STOP_STR2
735 CONFIG_ZERO_BOOTDELAY_CHECK
736 CONFIG_RESET_TO_RETRY
740 Only needed when CONFIG_BOOTDELAY is enabled;
741 define a command string that is automatically executed
742 when no character is read on the console interface
743 within "Boot Delay" after reset.
746 This can be used to pass arguments to the bootm
747 command. The value of CONFIG_BOOTARGS goes into the
748 environment value "bootargs".
750 CONFIG_RAMBOOT and CONFIG_NFSBOOT
751 The value of these goes into the environment as
752 "ramboot" and "nfsboot" respectively, and can be used
753 as a convenience, when switching between booting from
759 When this option is #defined, the existence of the
760 environment variable "preboot" will be checked
761 immediately before starting the CONFIG_BOOTDELAY
762 countdown and/or running the auto-boot command resp.
763 entering interactive mode.
765 This feature is especially useful when "preboot" is
766 automatically generated or modified. For an example
767 see the LWMON board specific code: here "preboot" is
768 modified when the user holds down a certain
769 combination of keys on the (special) keyboard when
772 - Serial Download Echo Mode:
774 If defined to 1, all characters received during a
775 serial download (using the "loads" command) are
776 echoed back. This might be needed by some terminal
777 emulations (like "cu"), but may as well just take
778 time on others. This setting #define's the initial
779 value of the "loads_echo" environment variable.
781 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
783 Select one of the baudrates listed in
784 CONFIG_SYS_BAUDRATE_TABLE, see below.
787 Monitor commands can be included or excluded
788 from the build by using the #include files
789 <config_cmd_all.h> and #undef'ing unwanted
790 commands, or using <config_cmd_default.h>
791 and augmenting with additional #define's
794 The default command configuration includes all commands
795 except those marked below with a "*".
797 CONFIG_CMD_ASKENV * ask for env variable
798 CONFIG_CMD_BDI bdinfo
799 CONFIG_CMD_BEDBUG * Include BedBug Debugger
800 CONFIG_CMD_BMP * BMP support
801 CONFIG_CMD_BSP * Board specific commands
802 CONFIG_CMD_BOOTD bootd
803 CONFIG_CMD_CACHE * icache, dcache
804 CONFIG_CMD_CONSOLE coninfo
805 CONFIG_CMD_CRC32 * crc32
806 CONFIG_CMD_DATE * support for RTC, date/time...
807 CONFIG_CMD_DHCP * DHCP support
808 CONFIG_CMD_DIAG * Diagnostics
809 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
810 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
811 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
812 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
813 CONFIG_CMD_DTT * Digital Therm and Thermostat
814 CONFIG_CMD_ECHO echo arguments
815 CONFIG_CMD_EDITENV edit env variable
816 CONFIG_CMD_EEPROM * EEPROM read/write support
817 CONFIG_CMD_ELF * bootelf, bootvx
818 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
819 CONFIG_CMD_ENV_FLAGS * display details about env flags
820 CONFIG_CMD_EXPORTENV * export the environment
821 CONFIG_CMD_EXT2 * ext2 command support
822 CONFIG_CMD_EXT4 * ext4 command support
823 CONFIG_CMD_SAVEENV saveenv
824 CONFIG_CMD_FDC * Floppy Disk Support
825 CONFIG_CMD_FAT * FAT command support
826 CONFIG_CMD_FDOS * Dos diskette Support
827 CONFIG_CMD_FLASH flinfo, erase, protect
828 CONFIG_CMD_FPGA FPGA device initialization support
829 CONFIG_CMD_GETTIME * Get time since boot
830 CONFIG_CMD_GO * the 'go' command (exec code)
831 CONFIG_CMD_GREPENV * search environment
832 CONFIG_CMD_HASH * calculate hash / digest
833 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
834 CONFIG_CMD_I2C * I2C serial bus support
835 CONFIG_CMD_IDE * IDE harddisk support
836 CONFIG_CMD_IMI iminfo
837 CONFIG_CMD_IMLS List all found images
838 CONFIG_CMD_IMMAP * IMMR dump support
839 CONFIG_CMD_IMPORTENV * import an environment
840 CONFIG_CMD_INI * import data from an ini file into the env
841 CONFIG_CMD_IRQ * irqinfo
842 CONFIG_CMD_ITEST Integer/string test of 2 values
843 CONFIG_CMD_JFFS2 * JFFS2 Support
844 CONFIG_CMD_KGDB * kgdb
845 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
846 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
848 CONFIG_CMD_LOADB loadb
849 CONFIG_CMD_LOADS loads
850 CONFIG_CMD_MD5SUM print md5 message digest
851 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
852 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
854 CONFIG_CMD_MISC Misc functions like sleep etc
855 CONFIG_CMD_MMC * MMC memory mapped support
856 CONFIG_CMD_MII * MII utility commands
857 CONFIG_CMD_MTDPARTS * MTD partition support
858 CONFIG_CMD_NAND * NAND support
859 CONFIG_CMD_NET bootp, tftpboot, rarpboot
860 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
861 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
862 CONFIG_CMD_PCI * pciinfo
863 CONFIG_CMD_PCMCIA * PCMCIA support
864 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
866 CONFIG_CMD_PORTIO * Port I/O
867 CONFIG_CMD_READ * Read raw data from partition
868 CONFIG_CMD_REGINFO * Register dump
869 CONFIG_CMD_RUN run command in env variable
870 CONFIG_CMD_SAVES * save S record dump
871 CONFIG_CMD_SCSI * SCSI Support
872 CONFIG_CMD_SDRAM * print SDRAM configuration information
873 (requires CONFIG_CMD_I2C)
874 CONFIG_CMD_SETGETDCR Support for DCR Register access
876 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
877 CONFIG_CMD_SHA1SUM print sha1 memory digest
878 (requires CONFIG_CMD_MEMORY)
879 CONFIG_CMD_SOURCE "source" command Support
880 CONFIG_CMD_SPI * SPI serial bus support
881 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
882 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
883 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
884 CONFIG_CMD_TIMER * access to the system tick timer
885 CONFIG_CMD_USB * USB support
886 CONFIG_CMD_CDP * Cisco Discover Protocol support
887 CONFIG_CMD_MFSL * Microblaze FSL support
890 EXAMPLE: If you want all functions except of network
891 support you can write:
893 #include "config_cmd_all.h"
894 #undef CONFIG_CMD_NET
897 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
899 Note: Don't enable the "icache" and "dcache" commands
900 (configuration option CONFIG_CMD_CACHE) unless you know
901 what you (and your U-Boot users) are doing. Data
902 cache cannot be enabled on systems like the 8xx or
903 8260 (where accesses to the IMMR region must be
904 uncached), and it cannot be disabled on all other
905 systems where we (mis-) use the data cache to hold an
906 initial stack and some data.
909 XXX - this list needs to get updated!
913 If this variable is defined, U-Boot will use a device tree
914 to configure its devices, instead of relying on statically
915 compiled #defines in the board file. This option is
916 experimental and only available on a few boards. The device
917 tree is available in the global data as gd->fdt_blob.
919 U-Boot needs to get its device tree from somewhere. This can
920 be done using one of the two options below:
923 If this variable is defined, U-Boot will embed a device tree
924 binary in its image. This device tree file should be in the
925 board directory and called <soc>-<board>.dts. The binary file
926 is then picked up in board_init_f() and made available through
927 the global data structure as gd->blob.
930 If this variable is defined, U-Boot will build a device tree
931 binary. It will be called u-boot.dtb. Architecture-specific
932 code will locate it at run-time. Generally this works by:
934 cat u-boot.bin u-boot.dtb >image.bin
936 and in fact, U-Boot does this for you, creating a file called
937 u-boot-dtb.bin which is useful in the common case. You can
938 still use the individual files if you need something more
943 If this variable is defined, it enables watchdog
944 support for the SoC. There must be support in the SoC
945 specific code for a watchdog. For the 8xx and 8260
946 CPUs, the SIU Watchdog feature is enabled in the SYPCR
947 register. When supported for a specific SoC is
948 available, then no further board specific code should
952 When using a watchdog circuitry external to the used
953 SoC, then define this variable and provide board
954 specific code for the "hw_watchdog_reset" function.
957 CONFIG_VERSION_VARIABLE
958 If this variable is defined, an environment variable
959 named "ver" is created by U-Boot showing the U-Boot
960 version as printed by the "version" command.
961 Any change to this variable will be reverted at the
966 When CONFIG_CMD_DATE is selected, the type of the RTC
967 has to be selected, too. Define exactly one of the
970 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
971 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
972 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
973 CONFIG_RTC_MC146818 - use MC146818 RTC
974 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
975 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
976 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
977 CONFIG_RTC_DS164x - use Dallas DS164x RTC
978 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
979 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
980 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
981 CONFIG_SYS_RV3029_TCR - enable trickle charger on
984 Note that if the RTC uses I2C, then the I2C interface
985 must also be configured. See I2C Support, below.
988 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
989 CONFIG_PCA953X_INFO - enable pca953x info command
991 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
992 chip-ngpio pairs that tell the PCA953X driver the number of
993 pins supported by a particular chip.
995 Note that if the GPIO device uses I2C, then the I2C interface
996 must also be configured. See I2C Support, below.
1000 When CONFIG_TIMESTAMP is selected, the timestamp
1001 (date and time) of an image is printed by image
1002 commands like bootm or iminfo. This option is
1003 automatically enabled when you select CONFIG_CMD_DATE .
1005 - Partition Labels (disklabels) Supported:
1006 Zero or more of the following:
1007 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1008 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1009 Intel architecture, USB sticks, etc.
1010 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1011 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1012 bootloader. Note 2TB partition limit; see
1014 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1016 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1017 CONFIG_CMD_SCSI) you must configure support for at
1018 least one non-MTD partition type as well.
1021 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1022 board configurations files but used nowhere!
1024 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1025 be performed by calling the function
1026 ide_set_reset(int reset)
1027 which has to be defined in a board specific file
1032 Set this to enable ATAPI support.
1037 Set this to enable support for disks larger than 137GB
1038 Also look at CONFIG_SYS_64BIT_LBA.
1039 Whithout these , LBA48 support uses 32bit variables and will 'only'
1040 support disks up to 2.1TB.
1042 CONFIG_SYS_64BIT_LBA:
1043 When enabled, makes the IDE subsystem use 64bit sector addresses.
1047 At the moment only there is only support for the
1048 SYM53C8XX SCSI controller; define
1049 CONFIG_SCSI_SYM53C8XX to enable it.
1051 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1052 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1053 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1054 maximum numbers of LUNs, SCSI ID's and target
1056 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1058 The environment variable 'scsidevs' is set to the number of
1059 SCSI devices found during the last scan.
1061 - NETWORK Support (PCI):
1063 Support for Intel 8254x/8257x gigabit chips.
1066 Utility code for direct access to the SPI bus on Intel 8257x.
1067 This does not do anything useful unless you set at least one
1068 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1070 CONFIG_E1000_SPI_GENERIC
1071 Allow generic access to the SPI bus on the Intel 8257x, for
1072 example with the "sspi" command.
1075 Management command for E1000 devices. When used on devices
1076 with SPI support you can reprogram the EEPROM from U-Boot.
1078 CONFIG_E1000_FALLBACK_MAC
1079 default MAC for empty EEPROM after production.
1082 Support for Intel 82557/82559/82559ER chips.
1083 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1084 write routine for first time initialisation.
1087 Support for Digital 2114x chips.
1088 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1089 modem chip initialisation (KS8761/QS6611).
1092 Support for National dp83815 chips.
1095 Support for National dp8382[01] gigabit chips.
1097 - NETWORK Support (other):
1099 CONFIG_DRIVER_AT91EMAC
1100 Support for AT91RM9200 EMAC.
1103 Define this to use reduced MII inteface
1105 CONFIG_DRIVER_AT91EMAC_QUIET
1106 If this defined, the driver is quiet.
1107 The driver doen't show link status messages.
1109 CONFIG_CALXEDA_XGMAC
1110 Support for the Calxeda XGMAC device
1113 Support for SMSC's LAN91C96 chips.
1115 CONFIG_LAN91C96_BASE
1116 Define this to hold the physical address
1117 of the LAN91C96's I/O space
1119 CONFIG_LAN91C96_USE_32_BIT
1120 Define this to enable 32 bit addressing
1123 Support for SMSC's LAN91C111 chip
1125 CONFIG_SMC91111_BASE
1126 Define this to hold the physical address
1127 of the device (I/O space)
1129 CONFIG_SMC_USE_32_BIT
1130 Define this if data bus is 32 bits
1132 CONFIG_SMC_USE_IOFUNCS
1133 Define this to use i/o functions instead of macros
1134 (some hardware wont work with macros)
1136 CONFIG_DRIVER_TI_EMAC
1137 Support for davinci emac
1139 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1140 Define this if you have more then 3 PHYs.
1143 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1145 CONFIG_FTGMAC100_EGIGA
1146 Define this to use GE link update with gigabit PHY.
1147 Define this if FTGMAC100 is connected to gigabit PHY.
1148 If your system has 10/100 PHY only, it might not occur
1149 wrong behavior. Because PHY usually return timeout or
1150 useless data when polling gigabit status and gigabit
1151 control registers. This behavior won't affect the
1152 correctnessof 10/100 link speed update.
1155 Support for SMSC's LAN911x and LAN921x chips
1158 Define this to hold the physical address
1159 of the device (I/O space)
1161 CONFIG_SMC911X_32_BIT
1162 Define this if data bus is 32 bits
1164 CONFIG_SMC911X_16_BIT
1165 Define this if data bus is 16 bits. If your processor
1166 automatically converts one 32 bit word to two 16 bit
1167 words you may also try CONFIG_SMC911X_32_BIT.
1170 Support for Renesas on-chip Ethernet controller
1172 CONFIG_SH_ETHER_USE_PORT
1173 Define the number of ports to be used
1175 CONFIG_SH_ETHER_PHY_ADDR
1176 Define the ETH PHY's address
1178 CONFIG_SH_ETHER_CACHE_WRITEBACK
1179 If this option is set, the driver enables cache flush.
1182 CONFIG_GENERIC_LPC_TPM
1183 Support for generic parallel port TPM devices. Only one device
1184 per system is supported at this time.
1186 CONFIG_TPM_TIS_BASE_ADDRESS
1187 Base address where the generic TPM device is mapped
1188 to. Contemporary x86 systems usually map it at
1192 At the moment only the UHCI host controller is
1193 supported (PIP405, MIP405, MPC5200); define
1194 CONFIG_USB_UHCI to enable it.
1195 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1196 and define CONFIG_USB_STORAGE to enable the USB
1199 Supported are USB Keyboards and USB Floppy drives
1201 MPC5200 USB requires additional defines:
1203 for 528 MHz Clock: 0x0001bbbb
1207 for differential drivers: 0x00001000
1208 for single ended drivers: 0x00005000
1209 for differential drivers on PSC3: 0x00000100
1210 for single ended drivers on PSC3: 0x00004100
1211 CONFIG_SYS_USB_EVENT_POLL
1212 May be defined to allow interrupt polling
1213 instead of using asynchronous interrupts
1215 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1216 txfilltuning field in the EHCI controller on reset.
1219 Define the below if you wish to use the USB console.
1220 Once firmware is rebuilt from a serial console issue the
1221 command "setenv stdin usbtty; setenv stdout usbtty" and
1222 attach your USB cable. The Unix command "dmesg" should print
1223 it has found a new device. The environment variable usbtty
1224 can be set to gserial or cdc_acm to enable your device to
1225 appear to a USB host as a Linux gserial device or a
1226 Common Device Class Abstract Control Model serial device.
1227 If you select usbtty = gserial you should be able to enumerate
1229 # modprobe usbserial vendor=0xVendorID product=0xProductID
1230 else if using cdc_acm, simply setting the environment
1231 variable usbtty to be cdc_acm should suffice. The following
1232 might be defined in YourBoardName.h
1235 Define this to build a UDC device
1238 Define this to have a tty type of device available to
1239 talk to the UDC device
1242 Define this to enable the high speed support for usb
1243 device and usbtty. If this feature is enabled, a routine
1244 int is_usbd_high_speed(void)
1245 also needs to be defined by the driver to dynamically poll
1246 whether the enumeration has succeded at high speed or full
1249 CONFIG_SYS_CONSOLE_IS_IN_ENV
1250 Define this if you want stdin, stdout &/or stderr to
1254 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1255 Derive USB clock from external clock "blah"
1256 - CONFIG_SYS_USB_EXTC_CLK 0x02
1258 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1259 Derive USB clock from brgclk
1260 - CONFIG_SYS_USB_BRG_CLK 0x04
1262 If you have a USB-IF assigned VendorID then you may wish to
1263 define your own vendor specific values either in BoardName.h
1264 or directly in usbd_vendor_info.h. If you don't define
1265 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1266 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1267 should pretend to be a Linux device to it's target host.
1269 CONFIG_USBD_MANUFACTURER
1270 Define this string as the name of your company for
1271 - CONFIG_USBD_MANUFACTURER "my company"
1273 CONFIG_USBD_PRODUCT_NAME
1274 Define this string as the name of your product
1275 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1277 CONFIG_USBD_VENDORID
1278 Define this as your assigned Vendor ID from the USB
1279 Implementors Forum. This *must* be a genuine Vendor ID
1280 to avoid polluting the USB namespace.
1281 - CONFIG_USBD_VENDORID 0xFFFF
1283 CONFIG_USBD_PRODUCTID
1284 Define this as the unique Product ID
1286 - CONFIG_USBD_PRODUCTID 0xFFFF
1288 - ULPI Layer Support:
1289 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1290 the generic ULPI layer. The generic layer accesses the ULPI PHY
1291 via the platform viewport, so you need both the genric layer and
1292 the viewport enabled. Currently only Chipidea/ARC based
1293 viewport is supported.
1294 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1295 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1296 If your ULPI phy needs a different reference clock than the
1297 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1298 the appropriate value in Hz.
1301 The MMC controller on the Intel PXA is supported. To
1302 enable this define CONFIG_MMC. The MMC can be
1303 accessed from the boot prompt by mapping the device
1304 to physical memory similar to flash. Command line is
1305 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1306 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1309 Support for Renesas on-chip MMCIF controller
1311 CONFIG_SH_MMCIF_ADDR
1312 Define the base address of MMCIF registers
1315 Define the clock frequency for MMCIF
1317 - Journaling Flash filesystem support:
1318 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1319 CONFIG_JFFS2_NAND_DEV
1320 Define these for a default partition on a NAND device
1322 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1323 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1324 Define these for a default partition on a NOR device
1326 CONFIG_SYS_JFFS_CUSTOM_PART
1327 Define this to create an own partition. You have to provide a
1328 function struct part_info* jffs2_part_info(int part_num)
1330 If you define only one JFFS2 partition you may also want to
1331 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1332 to disable the command chpart. This is the default when you
1333 have not defined a custom partition
1335 - FAT(File Allocation Table) filesystem write function support:
1338 Define this to enable support for saving memory data as a
1339 file in FAT formatted partition.
1341 This will also enable the command "fatwrite" enabling the
1342 user to write files to FAT.
1344 CBFS (Coreboot Filesystem) support
1347 Define this to enable support for reading from a Coreboot
1348 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1354 Define this to enable standard (PC-Style) keyboard
1358 Standard PC keyboard driver with US (is default) and
1359 GERMAN key layout (switch via environment 'keymap=de') support.
1360 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1361 for cfb_console. Supports cursor blinking.
1366 Define this to enable video support (for output to
1369 CONFIG_VIDEO_CT69000
1371 Enable Chips & Technologies 69000 Video chip
1373 CONFIG_VIDEO_SMI_LYNXEM
1374 Enable Silicon Motion SMI 712/710/810 Video chip. The
1375 video output is selected via environment 'videoout'
1376 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1379 For the CT69000 and SMI_LYNXEM drivers, videomode is
1380 selected via environment 'videomode'. Two different ways
1382 - "videomode=num" 'num' is a standard LiLo mode numbers.
1383 Following standard modes are supported (* is default):
1385 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1386 -------------+---------------------------------------------
1387 8 bits | 0x301* 0x303 0x305 0x161 0x307
1388 15 bits | 0x310 0x313 0x316 0x162 0x319
1389 16 bits | 0x311 0x314 0x317 0x163 0x31A
1390 24 bits | 0x312 0x315 0x318 ? 0x31B
1391 -------------+---------------------------------------------
1392 (i.e. setenv videomode 317; saveenv; reset;)
1394 - "videomode=bootargs" all the video parameters are parsed
1395 from the bootargs. (See drivers/video/videomodes.c)
1398 CONFIG_VIDEO_SED13806
1399 Enable Epson SED13806 driver. This driver supports 8bpp
1400 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1401 or CONFIG_VIDEO_SED13806_16BPP
1404 Enable the Freescale DIU video driver. Reference boards for
1405 SOCs that have a DIU should define this macro to enable DIU
1406 support, and should also define these other macros:
1412 CONFIG_VIDEO_SW_CURSOR
1413 CONFIG_VGA_AS_SINGLE_DEVICE
1415 CONFIG_VIDEO_BMP_LOGO
1417 The DIU driver will look for the 'video-mode' environment
1418 variable, and if defined, enable the DIU as a console during
1419 boot. See the documentation file README.video for a
1420 description of this variable.
1424 Enable the VGA video / BIOS for x86. The alternative if you
1425 are using coreboot is to use the coreboot frame buffer
1432 Define this to enable a custom keyboard support.
1433 This simply calls drv_keyboard_init() which must be
1434 defined in your board-specific files.
1435 The only board using this so far is RBC823.
1437 - LCD Support: CONFIG_LCD
1439 Define this to enable LCD support (for output to LCD
1440 display); also select one of the supported displays
1441 by defining one of these:
1445 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1447 CONFIG_NEC_NL6448AC33:
1449 NEC NL6448AC33-18. Active, color, single scan.
1451 CONFIG_NEC_NL6448BC20
1453 NEC NL6448BC20-08. 6.5", 640x480.
1454 Active, color, single scan.
1456 CONFIG_NEC_NL6448BC33_54
1458 NEC NL6448BC33-54. 10.4", 640x480.
1459 Active, color, single scan.
1463 Sharp 320x240. Active, color, single scan.
1464 It isn't 16x9, and I am not sure what it is.
1466 CONFIG_SHARP_LQ64D341
1468 Sharp LQ64D341 display, 640x480.
1469 Active, color, single scan.
1473 HLD1045 display, 640x480.
1474 Active, color, single scan.
1478 Optrex CBL50840-2 NF-FW 99 22 M5
1480 Hitachi LMG6912RPFC-00T
1484 320x240. Black & white.
1486 Normally display is black on white background; define
1487 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1491 Support drawing of RLE8-compressed bitmaps on the LCD.
1495 Enables an 'i2c edid' command which can read EDID
1496 information over I2C from an attached LCD display.
1499 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1501 If this option is set, the environment is checked for
1502 a variable "splashimage". If found, the usual display
1503 of logo, copyright and system information on the LCD
1504 is suppressed and the BMP image at the address
1505 specified in "splashimage" is loaded instead. The
1506 console is redirected to the "nulldev", too. This
1507 allows for a "silent" boot where a splash screen is
1508 loaded very quickly after power-on.
1510 CONFIG_SPLASH_SCREEN_ALIGN
1512 If this option is set the splash image can be freely positioned
1513 on the screen. Environment variable "splashpos" specifies the
1514 position as "x,y". If a positive number is given it is used as
1515 number of pixel from left/top. If a negative number is given it
1516 is used as number of pixel from right/bottom. You can also
1517 specify 'm' for centering the image.
1520 setenv splashpos m,m
1521 => image at center of screen
1523 setenv splashpos 30,20
1524 => image at x = 30 and y = 20
1526 setenv splashpos -10,m
1527 => vertically centered image
1528 at x = dspWidth - bmpWidth - 9
1530 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1532 If this option is set, additionally to standard BMP
1533 images, gzipped BMP images can be displayed via the
1534 splashscreen support or the bmp command.
1536 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1538 If this option is set, 8-bit RLE compressed BMP images
1539 can be displayed via the splashscreen support or the
1542 - Do compresssing for memory range:
1545 If this option is set, it would use zlib deflate method
1546 to compress the specified memory at its best effort.
1548 - Compression support:
1551 If this option is set, support for bzip2 compressed
1552 images is included. If not, only uncompressed and gzip
1553 compressed images are supported.
1555 NOTE: the bzip2 algorithm requires a lot of RAM, so
1556 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1561 If this option is set, support for lzma compressed
1564 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1565 requires an amount of dynamic memory that is given by the
1568 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1570 Where lc and lp stand for, respectively, Literal context bits
1571 and Literal pos bits.
1573 This value is upper-bounded by 14MB in the worst case. Anyway,
1574 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1575 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1576 a very small buffer.
1578 Use the lzmainfo tool to determinate the lc and lp values and
1579 then calculate the amount of needed dynamic memory (ensuring
1580 the appropriate CONFIG_SYS_MALLOC_LEN value).
1585 The address of PHY on MII bus.
1587 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1589 The clock frequency of the MII bus
1593 If this option is set, support for speed/duplex
1594 detection of gigabit PHY is included.
1596 CONFIG_PHY_RESET_DELAY
1598 Some PHY like Intel LXT971A need extra delay after
1599 reset before any MII register access is possible.
1600 For such PHY, set this option to the usec delay
1601 required. (minimum 300usec for LXT971A)
1603 CONFIG_PHY_CMD_DELAY (ppc4xx)
1605 Some PHY like Intel LXT971A need extra delay after
1606 command issued before MII status register can be read
1616 Define a default value for Ethernet address to use
1617 for the respective Ethernet interface, in case this
1618 is not determined automatically.
1623 Define a default value for the IP address to use for
1624 the default Ethernet interface, in case this is not
1625 determined through e.g. bootp.
1626 (Environment variable "ipaddr")
1628 - Server IP address:
1631 Defines a default value for the IP address of a TFTP
1632 server to contact when using the "tftboot" command.
1633 (Environment variable "serverip")
1635 CONFIG_KEEP_SERVERADDR
1637 Keeps the server's MAC address, in the env 'serveraddr'
1638 for passing to bootargs (like Linux's netconsole option)
1640 - Gateway IP address:
1643 Defines a default value for the IP address of the
1644 default router where packets to other networks are
1646 (Environment variable "gatewayip")
1651 Defines a default value for the subnet mask (or
1652 routing prefix) which is used to determine if an IP
1653 address belongs to the local subnet or needs to be
1654 forwarded through a router.
1655 (Environment variable "netmask")
1657 - Multicast TFTP Mode:
1660 Defines whether you want to support multicast TFTP as per
1661 rfc-2090; for example to work with atftp. Lets lots of targets
1662 tftp down the same boot image concurrently. Note: the Ethernet
1663 driver in use must provide a function: mcast() to join/leave a
1666 - BOOTP Recovery Mode:
1667 CONFIG_BOOTP_RANDOM_DELAY
1669 If you have many targets in a network that try to
1670 boot using BOOTP, you may want to avoid that all
1671 systems send out BOOTP requests at precisely the same
1672 moment (which would happen for instance at recovery
1673 from a power failure, when all systems will try to
1674 boot, thus flooding the BOOTP server. Defining
1675 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1676 inserted before sending out BOOTP requests. The
1677 following delays are inserted then:
1679 1st BOOTP request: delay 0 ... 1 sec
1680 2nd BOOTP request: delay 0 ... 2 sec
1681 3rd BOOTP request: delay 0 ... 4 sec
1683 BOOTP requests: delay 0 ... 8 sec
1685 - DHCP Advanced Options:
1686 You can fine tune the DHCP functionality by defining
1687 CONFIG_BOOTP_* symbols:
1689 CONFIG_BOOTP_SUBNETMASK
1690 CONFIG_BOOTP_GATEWAY
1691 CONFIG_BOOTP_HOSTNAME
1692 CONFIG_BOOTP_NISDOMAIN
1693 CONFIG_BOOTP_BOOTPATH
1694 CONFIG_BOOTP_BOOTFILESIZE
1697 CONFIG_BOOTP_SEND_HOSTNAME
1698 CONFIG_BOOTP_NTPSERVER
1699 CONFIG_BOOTP_TIMEOFFSET
1700 CONFIG_BOOTP_VENDOREX
1701 CONFIG_BOOTP_MAY_FAIL
1703 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1704 environment variable, not the BOOTP server.
1706 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1707 after the configured retry count, the call will fail
1708 instead of starting over. This can be used to fail over
1709 to Link-local IP address configuration if the DHCP server
1712 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1713 serverip from a DHCP server, it is possible that more
1714 than one DNS serverip is offered to the client.
1715 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1716 serverip will be stored in the additional environment
1717 variable "dnsip2". The first DNS serverip is always
1718 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1721 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1722 to do a dynamic update of a DNS server. To do this, they
1723 need the hostname of the DHCP requester.
1724 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1725 of the "hostname" environment variable is passed as
1726 option 12 to the DHCP server.
1728 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1730 A 32bit value in microseconds for a delay between
1731 receiving a "DHCP Offer" and sending the "DHCP Request".
1732 This fixes a problem with certain DHCP servers that don't
1733 respond 100% of the time to a "DHCP request". E.g. On an
1734 AT91RM9200 processor running at 180MHz, this delay needed
1735 to be *at least* 15,000 usec before a Windows Server 2003
1736 DHCP server would reply 100% of the time. I recommend at
1737 least 50,000 usec to be safe. The alternative is to hope
1738 that one of the retries will be successful but note that
1739 the DHCP timeout and retry process takes a longer than
1742 - Link-local IP address negotiation:
1743 Negotiate with other link-local clients on the local network
1744 for an address that doesn't require explicit configuration.
1745 This is especially useful if a DHCP server cannot be guaranteed
1746 to exist in all environments that the device must operate.
1748 See doc/README.link-local for more information.
1751 CONFIG_CDP_DEVICE_ID
1753 The device id used in CDP trigger frames.
1755 CONFIG_CDP_DEVICE_ID_PREFIX
1757 A two character string which is prefixed to the MAC address
1762 A printf format string which contains the ascii name of
1763 the port. Normally is set to "eth%d" which sets
1764 eth0 for the first Ethernet, eth1 for the second etc.
1766 CONFIG_CDP_CAPABILITIES
1768 A 32bit integer which indicates the device capabilities;
1769 0x00000010 for a normal host which does not forwards.
1773 An ascii string containing the version of the software.
1777 An ascii string containing the name of the platform.
1781 A 32bit integer sent on the trigger.
1783 CONFIG_CDP_POWER_CONSUMPTION
1785 A 16bit integer containing the power consumption of the
1786 device in .1 of milliwatts.
1788 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1790 A byte containing the id of the VLAN.
1792 - Status LED: CONFIG_STATUS_LED
1794 Several configurations allow to display the current
1795 status using a LED. For instance, the LED will blink
1796 fast while running U-Boot code, stop blinking as
1797 soon as a reply to a BOOTP request was received, and
1798 start blinking slow once the Linux kernel is running
1799 (supported by a status LED driver in the Linux
1800 kernel). Defining CONFIG_STATUS_LED enables this
1803 - CAN Support: CONFIG_CAN_DRIVER
1805 Defining CONFIG_CAN_DRIVER enables CAN driver support
1806 on those systems that support this (optional)
1807 feature, like the TQM8xxL modules.
1809 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1811 These enable I2C serial bus commands. Defining either of
1812 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1813 include the appropriate I2C driver for the selected CPU.
1815 This will allow you to use i2c commands at the u-boot
1816 command line (as long as you set CONFIG_CMD_I2C in
1817 CONFIG_COMMANDS) and communicate with i2c based realtime
1818 clock chips. See common/cmd_i2c.c for a description of the
1819 command line interface.
1821 CONFIG_HARD_I2C selects a hardware I2C controller.
1823 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1824 bit-banging) driver instead of CPM or similar hardware
1827 There are several other quantities that must also be
1828 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1830 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1831 to be the frequency (in Hz) at which you wish your i2c bus
1832 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1833 the CPU's i2c node address).
1835 Now, the u-boot i2c code for the mpc8xx
1836 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1837 and so its address should therefore be cleared to 0 (See,
1838 eg, MPC823e User's Manual p.16-473). So, set
1839 CONFIG_SYS_I2C_SLAVE to 0.
1841 CONFIG_SYS_I2C_INIT_MPC5XXX
1843 When a board is reset during an i2c bus transfer
1844 chips might think that the current transfer is still
1845 in progress. Reset the slave devices by sending start
1846 commands until the slave device responds.
1848 That's all that's required for CONFIG_HARD_I2C.
1850 If you use the software i2c interface (CONFIG_SOFT_I2C)
1851 then the following macros need to be defined (examples are
1852 from include/configs/lwmon.h):
1856 (Optional). Any commands necessary to enable the I2C
1857 controller or configure ports.
1859 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1863 (Only for MPC8260 CPU). The I/O port to use (the code
1864 assumes both bits are on the same port). Valid values
1865 are 0..3 for ports A..D.
1869 The code necessary to make the I2C data line active
1870 (driven). If the data line is open collector, this
1873 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1877 The code necessary to make the I2C data line tri-stated
1878 (inactive). If the data line is open collector, this
1881 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1885 Code that returns TRUE if the I2C data line is high,
1888 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1892 If <bit> is TRUE, sets the I2C data line high. If it
1893 is FALSE, it clears it (low).
1895 eg: #define I2C_SDA(bit) \
1896 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1897 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1901 If <bit> is TRUE, sets the I2C clock line high. If it
1902 is FALSE, it clears it (low).
1904 eg: #define I2C_SCL(bit) \
1905 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1906 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1910 This delay is invoked four times per clock cycle so this
1911 controls the rate of data transfer. The data rate thus
1912 is 1 / (I2C_DELAY * 4). Often defined to be something
1915 #define I2C_DELAY udelay(2)
1917 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1919 If your arch supports the generic GPIO framework (asm/gpio.h),
1920 then you may alternatively define the two GPIOs that are to be
1921 used as SCL / SDA. Any of the previous I2C_xxx macros will
1922 have GPIO-based defaults assigned to them as appropriate.
1924 You should define these to the GPIO value as given directly to
1925 the generic GPIO functions.
1927 CONFIG_SYS_I2C_INIT_BOARD
1929 When a board is reset during an i2c bus transfer
1930 chips might think that the current transfer is still
1931 in progress. On some boards it is possible to access
1932 the i2c SCLK line directly, either by using the
1933 processor pin as a GPIO or by having a second pin
1934 connected to the bus. If this option is defined a
1935 custom i2c_init_board() routine in boards/xxx/board.c
1936 is run early in the boot sequence.
1938 CONFIG_SYS_I2C_BOARD_LATE_INIT
1940 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1941 defined a custom i2c_board_late_init() routine in
1942 boards/xxx/board.c is run AFTER the operations in i2c_init()
1943 is completed. This callpoint can be used to unreset i2c bus
1944 using CPU i2c controller register accesses for CPUs whose i2c
1945 controller provide such a method. It is called at the end of
1946 i2c_init() to allow i2c_init operations to setup the i2c bus
1947 controller on the CPU (e.g. setting bus speed & slave address).
1949 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1951 This option enables configuration of bi_iic_fast[] flags
1952 in u-boot bd_info structure based on u-boot environment
1953 variable "i2cfast". (see also i2cfast)
1955 CONFIG_I2C_MULTI_BUS
1957 This option allows the use of multiple I2C buses, each of which
1958 must have a controller. At any point in time, only one bus is
1959 active. To switch to a different bus, use the 'i2c dev' command.
1960 Note that bus numbering is zero-based.
1962 CONFIG_SYS_I2C_NOPROBES
1964 This option specifies a list of I2C devices that will be skipped
1965 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1966 is set, specify a list of bus-device pairs. Otherwise, specify
1967 a 1D array of device addresses
1970 #undef CONFIG_I2C_MULTI_BUS
1971 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1973 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1975 #define CONFIG_I2C_MULTI_BUS
1976 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1978 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1980 CONFIG_SYS_SPD_BUS_NUM
1982 If defined, then this indicates the I2C bus number for DDR SPD.
1983 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1985 CONFIG_SYS_RTC_BUS_NUM
1987 If defined, then this indicates the I2C bus number for the RTC.
1988 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1990 CONFIG_SYS_DTT_BUS_NUM
1992 If defined, then this indicates the I2C bus number for the DTT.
1993 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1995 CONFIG_SYS_I2C_DTT_ADDR:
1997 If defined, specifies the I2C address of the DTT device.
1998 If not defined, then U-Boot uses predefined value for
1999 specified DTT device.
2003 Define this option if you want to use Freescale's I2C driver in
2004 drivers/i2c/fsl_i2c.c.
2008 Define this option if you have I2C devices reached over 1 .. n
2009 I2C Muxes like the pca9544a. This option addes a new I2C
2010 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2011 new I2C Bus to the existing I2C Busses. If you select the
2012 new Bus with "i2c dev", u-bbot sends first the commandos for
2013 the muxes to activate this new "bus".
2015 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2019 Adding a new I2C Bus reached over 2 pca9544a muxes
2020 The First mux with address 70 and channel 6
2021 The Second mux with address 71 and channel 4
2023 => i2c bus pca9544a:70:6:pca9544a:71:4
2025 Use the "i2c bus" command without parameter, to get a list
2026 of I2C Busses with muxes:
2029 Busses reached over muxes:
2031 reached over Mux(es):
2034 reached over Mux(es):
2039 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2040 u-boot first sends the command to the mux@70 to enable
2041 channel 6, and then the command to the mux@71 to enable
2044 After that, you can use the "normal" i2c commands as
2045 usual to communicate with your I2C devices behind
2048 This option is actually implemented for the bitbanging
2049 algorithm in common/soft_i2c.c and for the Hardware I2C
2050 Bus on the MPC8260. But it should be not so difficult
2051 to add this option to other architectures.
2053 CONFIG_SOFT_I2C_READ_REPEATED_START
2055 defining this will force the i2c_read() function in
2056 the soft_i2c driver to perform an I2C repeated start
2057 between writing the address pointer and reading the
2058 data. If this define is omitted the default behaviour
2059 of doing a stop-start sequence will be used. Most I2C
2060 devices can use either method, but some require one or
2063 - SPI Support: CONFIG_SPI
2065 Enables SPI driver (so far only tested with
2066 SPI EEPROM, also an instance works with Crystal A/D and
2067 D/As on the SACSng board)
2071 Enables the driver for SPI controller on SuperH. Currently
2072 only SH7757 is supported.
2076 Enables extended (16-bit) SPI EEPROM addressing.
2077 (symmetrical to CONFIG_I2C_X)
2081 Enables a software (bit-bang) SPI driver rather than
2082 using hardware support. This is a general purpose
2083 driver that only requires three general I/O port pins
2084 (two outputs, one input) to function. If this is
2085 defined, the board configuration must define several
2086 SPI configuration items (port pins to use, etc). For
2087 an example, see include/configs/sacsng.h.
2091 Enables a hardware SPI driver for general-purpose reads
2092 and writes. As with CONFIG_SOFT_SPI, the board configuration
2093 must define a list of chip-select function pointers.
2094 Currently supported on some MPC8xxx processors. For an
2095 example, see include/configs/mpc8349emds.h.
2099 Enables the driver for the SPI controllers on i.MX and MXC
2100 SoCs. Currently i.MX31/35/51 are supported.
2102 - FPGA Support: CONFIG_FPGA
2104 Enables FPGA subsystem.
2106 CONFIG_FPGA_<vendor>
2108 Enables support for specific chip vendors.
2111 CONFIG_FPGA_<family>
2113 Enables support for FPGA family.
2114 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2118 Specify the number of FPGA devices to support.
2120 CONFIG_SYS_FPGA_PROG_FEEDBACK
2122 Enable printing of hash marks during FPGA configuration.
2124 CONFIG_SYS_FPGA_CHECK_BUSY
2126 Enable checks on FPGA configuration interface busy
2127 status by the configuration function. This option
2128 will require a board or device specific function to
2133 If defined, a function that provides delays in the FPGA
2134 configuration driver.
2136 CONFIG_SYS_FPGA_CHECK_CTRLC
2137 Allow Control-C to interrupt FPGA configuration
2139 CONFIG_SYS_FPGA_CHECK_ERROR
2141 Check for configuration errors during FPGA bitfile
2142 loading. For example, abort during Virtex II
2143 configuration if the INIT_B line goes low (which
2144 indicated a CRC error).
2146 CONFIG_SYS_FPGA_WAIT_INIT
2148 Maximum time to wait for the INIT_B line to deassert
2149 after PROB_B has been deasserted during a Virtex II
2150 FPGA configuration sequence. The default time is 500
2153 CONFIG_SYS_FPGA_WAIT_BUSY
2155 Maximum time to wait for BUSY to deassert during
2156 Virtex II FPGA configuration. The default is 5 ms.
2158 CONFIG_SYS_FPGA_WAIT_CONFIG
2160 Time to wait after FPGA configuration. The default is
2163 - Configuration Management:
2166 If defined, this string will be added to the U-Boot
2167 version information (U_BOOT_VERSION)
2169 - Vendor Parameter Protection:
2171 U-Boot considers the values of the environment
2172 variables "serial#" (Board Serial Number) and
2173 "ethaddr" (Ethernet Address) to be parameters that
2174 are set once by the board vendor / manufacturer, and
2175 protects these variables from casual modification by
2176 the user. Once set, these variables are read-only,
2177 and write or delete attempts are rejected. You can
2178 change this behaviour:
2180 If CONFIG_ENV_OVERWRITE is #defined in your config
2181 file, the write protection for vendor parameters is
2182 completely disabled. Anybody can change or delete
2185 Alternatively, if you #define _both_ CONFIG_ETHADDR
2186 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2187 Ethernet address is installed in the environment,
2188 which can be changed exactly ONCE by the user. [The
2189 serial# is unaffected by this, i. e. it remains
2192 The same can be accomplished in a more flexible way
2193 for any variable by configuring the type of access
2194 to allow for those variables in the ".flags" variable
2195 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2200 Define this variable to enable the reservation of
2201 "protected RAM", i. e. RAM which is not overwritten
2202 by U-Boot. Define CONFIG_PRAM to hold the number of
2203 kB you want to reserve for pRAM. You can overwrite
2204 this default value by defining an environment
2205 variable "pram" to the number of kB you want to
2206 reserve. Note that the board info structure will
2207 still show the full amount of RAM. If pRAM is
2208 reserved, a new environment variable "mem" will
2209 automatically be defined to hold the amount of
2210 remaining RAM in a form that can be passed as boot
2211 argument to Linux, for instance like that:
2213 setenv bootargs ... mem=\${mem}
2216 This way you can tell Linux not to use this memory,
2217 either, which results in a memory region that will
2218 not be affected by reboots.
2220 *WARNING* If your board configuration uses automatic
2221 detection of the RAM size, you must make sure that
2222 this memory test is non-destructive. So far, the
2223 following board configurations are known to be
2226 IVMS8, IVML24, SPD8xx, TQM8xxL,
2227 HERMES, IP860, RPXlite, LWMON,
2230 - Access to physical memory region (> 4GB)
2231 Some basic support is provided for operations on memory not
2232 normally accessible to U-Boot - e.g. some architectures
2233 support access to more than 4GB of memory on 32-bit
2234 machines using physical address extension or similar.
2235 Define CONFIG_PHYSMEM to access this basic support, which
2236 currently only supports clearing the memory.
2241 Define this variable to stop the system in case of a
2242 fatal error, so that you have to reset it manually.
2243 This is probably NOT a good idea for an embedded
2244 system where you want the system to reboot
2245 automatically as fast as possible, but it may be
2246 useful during development since you can try to debug
2247 the conditions that lead to the situation.
2249 CONFIG_NET_RETRY_COUNT
2251 This variable defines the number of retries for
2252 network operations like ARP, RARP, TFTP, or BOOTP
2253 before giving up the operation. If not defined, a
2254 default value of 5 is used.
2258 Timeout waiting for an ARP reply in milliseconds.
2262 Timeout in milliseconds used in NFS protocol.
2263 If you encounter "ERROR: Cannot umount" in nfs command,
2264 try longer timeout such as
2265 #define CONFIG_NFS_TIMEOUT 10000UL
2267 - Command Interpreter:
2268 CONFIG_AUTO_COMPLETE
2270 Enable auto completion of commands using TAB.
2272 Note that this feature has NOT been implemented yet
2273 for the "hush" shell.
2276 CONFIG_SYS_HUSH_PARSER
2278 Define this variable to enable the "hush" shell (from
2279 Busybox) as command line interpreter, thus enabling
2280 powerful command line syntax like
2281 if...then...else...fi conditionals or `&&' and '||'
2282 constructs ("shell scripts").
2284 If undefined, you get the old, much simpler behaviour
2285 with a somewhat smaller memory footprint.
2288 CONFIG_SYS_PROMPT_HUSH_PS2
2290 This defines the secondary prompt string, which is
2291 printed when the command interpreter needs more input
2292 to complete a command. Usually "> ".
2296 In the current implementation, the local variables
2297 space and global environment variables space are
2298 separated. Local variables are those you define by
2299 simply typing `name=value'. To access a local
2300 variable later on, you have write `$name' or
2301 `${name}'; to execute the contents of a variable
2302 directly type `$name' at the command prompt.
2304 Global environment variables are those you use
2305 setenv/printenv to work with. To run a command stored
2306 in such a variable, you need to use the run command,
2307 and you must not use the '$' sign to access them.
2309 To store commands and special characters in a
2310 variable, please use double quotation marks
2311 surrounding the whole text of the variable, instead
2312 of the backslashes before semicolons and special
2315 - Commandline Editing and History:
2316 CONFIG_CMDLINE_EDITING
2318 Enable editing and History functions for interactive
2319 commandline input operations
2321 - Default Environment:
2322 CONFIG_EXTRA_ENV_SETTINGS
2324 Define this to contain any number of null terminated
2325 strings (variable = value pairs) that will be part of
2326 the default environment compiled into the boot image.
2328 For example, place something like this in your
2329 board's config file:
2331 #define CONFIG_EXTRA_ENV_SETTINGS \
2335 Warning: This method is based on knowledge about the
2336 internal format how the environment is stored by the
2337 U-Boot code. This is NOT an official, exported
2338 interface! Although it is unlikely that this format
2339 will change soon, there is no guarantee either.
2340 You better know what you are doing here.
2342 Note: overly (ab)use of the default environment is
2343 discouraged. Make sure to check other ways to preset
2344 the environment like the "source" command or the
2347 CONFIG_ENV_VARS_UBOOT_CONFIG
2349 Define this in order to add variables describing the
2350 U-Boot build configuration to the default environment.
2351 These will be named arch, cpu, board, vendor, and soc.
2353 Enabling this option will cause the following to be defined:
2361 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2363 Define this in order to add variables describing certain
2364 run-time determined information about the hardware to the
2365 environment. These will be named board_name, board_rev.
2367 - DataFlash Support:
2368 CONFIG_HAS_DATAFLASH
2370 Defining this option enables DataFlash features and
2371 allows to read/write in Dataflash via the standard
2374 - Serial Flash support
2377 Defining this option enables SPI flash commands
2378 'sf probe/read/write/erase/update'.
2380 Usage requires an initial 'probe' to define the serial
2381 flash parameters, followed by read/write/erase/update
2384 The following defaults may be provided by the platform
2385 to handle the common case when only a single serial
2386 flash is present on the system.
2388 CONFIG_SF_DEFAULT_BUS Bus identifier
2389 CONFIG_SF_DEFAULT_CS Chip-select
2390 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2391 CONFIG_SF_DEFAULT_SPEED in Hz
2393 - SystemACE Support:
2396 Adding this option adds support for Xilinx SystemACE
2397 chips attached via some sort of local bus. The address
2398 of the chip must also be defined in the
2399 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2401 #define CONFIG_SYSTEMACE
2402 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2404 When SystemACE support is added, the "ace" device type
2405 becomes available to the fat commands, i.e. fatls.
2407 - TFTP Fixed UDP Port:
2410 If this is defined, the environment variable tftpsrcp
2411 is used to supply the TFTP UDP source port value.
2412 If tftpsrcp isn't defined, the normal pseudo-random port
2413 number generator is used.
2415 Also, the environment variable tftpdstp is used to supply
2416 the TFTP UDP destination port value. If tftpdstp isn't
2417 defined, the normal port 69 is used.
2419 The purpose for tftpsrcp is to allow a TFTP server to
2420 blindly start the TFTP transfer using the pre-configured
2421 target IP address and UDP port. This has the effect of
2422 "punching through" the (Windows XP) firewall, allowing
2423 the remainder of the TFTP transfer to proceed normally.
2424 A better solution is to properly configure the firewall,
2425 but sometimes that is not allowed.
2430 This enables a generic 'hash' command which can produce
2431 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2435 Enable the hash verify command (hash -v). This adds to code
2438 CONFIG_SHA1 - support SHA1 hashing
2439 CONFIG_SHA256 - support SHA256 hashing
2441 Note: There is also a sha1sum command, which should perhaps
2442 be deprecated in favour of 'hash sha1'.
2444 - Show boot progress:
2445 CONFIG_SHOW_BOOT_PROGRESS
2447 Defining this option allows to add some board-
2448 specific code (calling a user-provided function
2449 "show_boot_progress(int)") that enables you to show
2450 the system's boot progress on some display (for
2451 example, some LED's) on your board. At the moment,
2452 the following checkpoints are implemented:
2454 - Detailed boot stage timing
2456 Define this option to get detailed timing of each stage
2457 of the boot process.
2459 CONFIG_BOOTSTAGE_USER_COUNT
2460 This is the number of available user bootstage records.
2461 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2462 a new ID will be allocated from this stash. If you exceed
2463 the limit, recording will stop.
2465 CONFIG_BOOTSTAGE_REPORT
2466 Define this to print a report before boot, similar to this:
2468 Timer summary in microseconds:
2471 3,575,678 3,575,678 board_init_f start
2472 3,575,695 17 arch_cpu_init A9
2473 3,575,777 82 arch_cpu_init done
2474 3,659,598 83,821 board_init_r start
2475 3,910,375 250,777 main_loop
2476 29,916,167 26,005,792 bootm_start
2477 30,361,327 445,160 start_kernel
2479 CONFIG_CMD_BOOTSTAGE
2480 Add a 'bootstage' command which supports printing a report
2481 and un/stashing of bootstage data.
2483 CONFIG_BOOTSTAGE_FDT
2484 Stash the bootstage information in the FDT. A root 'bootstage'
2485 node is created with each bootstage id as a child. Each child
2486 has a 'name' property and either 'mark' containing the
2487 mark time in microsecond, or 'accum' containing the
2488 accumulated time for that bootstage id in microseconds.
2493 name = "board_init_f";
2502 Code in the Linux kernel can find this in /proc/devicetree.
2504 Legacy uImage format:
2507 1 common/cmd_bootm.c before attempting to boot an image
2508 -1 common/cmd_bootm.c Image header has bad magic number
2509 2 common/cmd_bootm.c Image header has correct magic number
2510 -2 common/cmd_bootm.c Image header has bad checksum
2511 3 common/cmd_bootm.c Image header has correct checksum
2512 -3 common/cmd_bootm.c Image data has bad checksum
2513 4 common/cmd_bootm.c Image data has correct checksum
2514 -4 common/cmd_bootm.c Image is for unsupported architecture
2515 5 common/cmd_bootm.c Architecture check OK
2516 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2517 6 common/cmd_bootm.c Image Type check OK
2518 -6 common/cmd_bootm.c gunzip uncompression error
2519 -7 common/cmd_bootm.c Unimplemented compression type
2520 7 common/cmd_bootm.c Uncompression OK
2521 8 common/cmd_bootm.c No uncompress/copy overwrite error
2522 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2524 9 common/image.c Start initial ramdisk verification
2525 -10 common/image.c Ramdisk header has bad magic number
2526 -11 common/image.c Ramdisk header has bad checksum
2527 10 common/image.c Ramdisk header is OK
2528 -12 common/image.c Ramdisk data has bad checksum
2529 11 common/image.c Ramdisk data has correct checksum
2530 12 common/image.c Ramdisk verification complete, start loading
2531 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2532 13 common/image.c Start multifile image verification
2533 14 common/image.c No initial ramdisk, no multifile, continue.
2535 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2537 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2538 -31 post/post.c POST test failed, detected by post_output_backlog()
2539 -32 post/post.c POST test failed, detected by post_run_single()
2541 34 common/cmd_doc.c before loading a Image from a DOC device
2542 -35 common/cmd_doc.c Bad usage of "doc" command
2543 35 common/cmd_doc.c correct usage of "doc" command
2544 -36 common/cmd_doc.c No boot device
2545 36 common/cmd_doc.c correct boot device
2546 -37 common/cmd_doc.c Unknown Chip ID on boot device
2547 37 common/cmd_doc.c correct chip ID found, device available
2548 -38 common/cmd_doc.c Read Error on boot device
2549 38 common/cmd_doc.c reading Image header from DOC device OK
2550 -39 common/cmd_doc.c Image header has bad magic number
2551 39 common/cmd_doc.c Image header has correct magic number
2552 -40 common/cmd_doc.c Error reading Image from DOC device
2553 40 common/cmd_doc.c Image header has correct magic number
2554 41 common/cmd_ide.c before loading a Image from a IDE device
2555 -42 common/cmd_ide.c Bad usage of "ide" command
2556 42 common/cmd_ide.c correct usage of "ide" command
2557 -43 common/cmd_ide.c No boot device
2558 43 common/cmd_ide.c boot device found
2559 -44 common/cmd_ide.c Device not available
2560 44 common/cmd_ide.c Device available
2561 -45 common/cmd_ide.c wrong partition selected
2562 45 common/cmd_ide.c partition selected
2563 -46 common/cmd_ide.c Unknown partition table
2564 46 common/cmd_ide.c valid partition table found
2565 -47 common/cmd_ide.c Invalid partition type
2566 47 common/cmd_ide.c correct partition type
2567 -48 common/cmd_ide.c Error reading Image Header on boot device
2568 48 common/cmd_ide.c reading Image Header from IDE device OK
2569 -49 common/cmd_ide.c Image header has bad magic number
2570 49 common/cmd_ide.c Image header has correct magic number
2571 -50 common/cmd_ide.c Image header has bad checksum
2572 50 common/cmd_ide.c Image header has correct checksum
2573 -51 common/cmd_ide.c Error reading Image from IDE device
2574 51 common/cmd_ide.c reading Image from IDE device OK
2575 52 common/cmd_nand.c before loading a Image from a NAND device
2576 -53 common/cmd_nand.c Bad usage of "nand" command
2577 53 common/cmd_nand.c correct usage of "nand" command
2578 -54 common/cmd_nand.c No boot device
2579 54 common/cmd_nand.c boot device found
2580 -55 common/cmd_nand.c Unknown Chip ID on boot device
2581 55 common/cmd_nand.c correct chip ID found, device available
2582 -56 common/cmd_nand.c Error reading Image Header on boot device
2583 56 common/cmd_nand.c reading Image Header from NAND device OK
2584 -57 common/cmd_nand.c Image header has bad magic number
2585 57 common/cmd_nand.c Image header has correct magic number
2586 -58 common/cmd_nand.c Error reading Image from NAND device
2587 58 common/cmd_nand.c reading Image from NAND device OK
2589 -60 common/env_common.c Environment has a bad CRC, using default
2591 64 net/eth.c starting with Ethernet configuration.
2592 -64 net/eth.c no Ethernet found.
2593 65 net/eth.c Ethernet found.
2595 -80 common/cmd_net.c usage wrong
2596 80 common/cmd_net.c before calling NetLoop()
2597 -81 common/cmd_net.c some error in NetLoop() occurred
2598 81 common/cmd_net.c NetLoop() back without error
2599 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2600 82 common/cmd_net.c trying automatic boot
2601 83 common/cmd_net.c running "source" command
2602 -83 common/cmd_net.c some error in automatic boot or "source" command
2603 84 common/cmd_net.c end without errors
2608 100 common/cmd_bootm.c Kernel FIT Image has correct format
2609 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2610 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2611 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2612 102 common/cmd_bootm.c Kernel unit name specified
2613 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2614 103 common/cmd_bootm.c Found configuration node
2615 104 common/cmd_bootm.c Got kernel subimage node offset
2616 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2617 105 common/cmd_bootm.c Kernel subimage hash verification OK
2618 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2619 106 common/cmd_bootm.c Architecture check OK
2620 -106 common/cmd_bootm.c Kernel subimage has wrong type
2621 107 common/cmd_bootm.c Kernel subimage type OK
2622 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2623 108 common/cmd_bootm.c Got kernel subimage data/size
2624 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2625 -109 common/cmd_bootm.c Can't get kernel subimage type
2626 -110 common/cmd_bootm.c Can't get kernel subimage comp
2627 -111 common/cmd_bootm.c Can't get kernel subimage os
2628 -112 common/cmd_bootm.c Can't get kernel subimage load address
2629 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2631 120 common/image.c Start initial ramdisk verification
2632 -120 common/image.c Ramdisk FIT image has incorrect format
2633 121 common/image.c Ramdisk FIT image has correct format
2634 122 common/image.c No ramdisk subimage unit name, using configuration
2635 -122 common/image.c Can't get configuration for ramdisk subimage
2636 123 common/image.c Ramdisk unit name specified
2637 -124 common/image.c Can't get ramdisk subimage node offset
2638 125 common/image.c Got ramdisk subimage node offset
2639 -125 common/image.c Ramdisk subimage hash verification failed
2640 126 common/image.c Ramdisk subimage hash verification OK
2641 -126 common/image.c Ramdisk subimage for unsupported architecture
2642 127 common/image.c Architecture check OK
2643 -127 common/image.c Can't get ramdisk subimage data/size
2644 128 common/image.c Got ramdisk subimage data/size
2645 129 common/image.c Can't get ramdisk load address
2646 -129 common/image.c Got ramdisk load address
2648 -130 common/cmd_doc.c Incorrect FIT image format
2649 131 common/cmd_doc.c FIT image format OK
2651 -140 common/cmd_ide.c Incorrect FIT image format
2652 141 common/cmd_ide.c FIT image format OK
2654 -150 common/cmd_nand.c Incorrect FIT image format
2655 151 common/cmd_nand.c FIT image format OK
2657 - FIT image support:
2659 Enable support for the FIT uImage format.
2661 CONFIG_FIT_BEST_MATCH
2662 When no configuration is explicitly selected, default to the
2663 one whose fdt's compatibility field best matches that of
2664 U-Boot itself. A match is considered "best" if it matches the
2665 most specific compatibility entry of U-Boot's fdt's root node.
2666 The order of entries in the configuration's fdt is ignored.
2668 - Standalone program support:
2669 CONFIG_STANDALONE_LOAD_ADDR
2671 This option defines a board specific value for the
2672 address where standalone program gets loaded, thus
2673 overwriting the architecture dependent default
2676 - Frame Buffer Address:
2679 Define CONFIG_FB_ADDR if you want to use specific
2680 address for frame buffer.
2681 Then system will reserve the frame buffer address to
2682 defined address instead of lcd_setmem (this function
2683 grabs the memory for frame buffer by panel's size).
2685 Please see board_init_f function.
2687 - Automatic software updates via TFTP server
2689 CONFIG_UPDATE_TFTP_CNT_MAX
2690 CONFIG_UPDATE_TFTP_MSEC_MAX
2692 These options enable and control the auto-update feature;
2693 for a more detailed description refer to doc/README.update.
2695 - MTD Support (mtdparts command, UBI support)
2698 Adds the MTD device infrastructure from the Linux kernel.
2699 Needed for mtdparts command support.
2701 CONFIG_MTD_PARTITIONS
2703 Adds the MTD partitioning infrastructure from the Linux
2704 kernel. Needed for UBI support.
2708 Enable building of SPL globally.
2711 LDSCRIPT for linking the SPL binary.
2714 Maximum binary size (text, data and rodata) of the SPL binary.
2716 CONFIG_SPL_TEXT_BASE
2717 TEXT_BASE for linking the SPL binary.
2719 CONFIG_SPL_RELOC_TEXT_BASE
2720 Address to relocate to. If unspecified, this is equal to
2721 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2723 CONFIG_SPL_BSS_START_ADDR
2724 Link address for the BSS within the SPL binary.
2726 CONFIG_SPL_BSS_MAX_SIZE
2727 Maximum binary size of the BSS section of the SPL binary.
2730 Adress of the start of the stack SPL will use
2732 CONFIG_SPL_RELOC_STACK
2733 Adress of the start of the stack SPL will use after
2734 relocation. If unspecified, this is equal to
2737 CONFIG_SYS_SPL_MALLOC_START
2738 Starting address of the malloc pool used in SPL.
2740 CONFIG_SYS_SPL_MALLOC_SIZE
2741 The size of the malloc pool used in SPL.
2743 CONFIG_SPL_FRAMEWORK
2744 Enable the SPL framework under common/. This framework
2745 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2746 NAND loading of the Linux Kernel.
2748 CONFIG_SPL_DISPLAY_PRINT
2749 For ARM, enable an optional function to print more information
2750 about the running system.
2752 CONFIG_SPL_INIT_MINIMAL
2753 Arch init code should be built for a very small image
2755 CONFIG_SPL_LIBCOMMON_SUPPORT
2756 Support for common/libcommon.o in SPL binary
2758 CONFIG_SPL_LIBDISK_SUPPORT
2759 Support for disk/libdisk.o in SPL binary
2761 CONFIG_SPL_I2C_SUPPORT
2762 Support for drivers/i2c/libi2c.o in SPL binary
2764 CONFIG_SPL_GPIO_SUPPORT
2765 Support for drivers/gpio/libgpio.o in SPL binary
2767 CONFIG_SPL_MMC_SUPPORT
2768 Support for drivers/mmc/libmmc.o in SPL binary
2770 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2771 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2772 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2773 Address, size and partition on the MMC to load U-Boot from
2774 when the MMC is being used in raw mode.
2776 CONFIG_SPL_FAT_SUPPORT
2777 Support for fs/fat/libfat.o in SPL binary
2779 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2780 Filename to read to load U-Boot when reading from FAT
2782 CONFIG_SPL_NAND_BASE
2783 Include nand_base.c in the SPL. Requires
2784 CONFIG_SPL_NAND_DRIVERS.
2786 CONFIG_SPL_NAND_DRIVERS
2787 SPL uses normal NAND drivers, not minimal drivers.
2790 Include standard software ECC in the SPL
2792 CONFIG_SPL_NAND_SIMPLE
2793 Support for NAND boot using simple NAND drivers that
2794 expose the cmd_ctrl() interface.
2796 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2797 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2798 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2799 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2800 CONFIG_SYS_NAND_ECCBYTES
2801 Defines the size and behavior of the NAND that SPL uses
2804 CONFIG_SYS_NAND_U_BOOT_OFFS
2805 Location in NAND to read U-Boot from
2807 CONFIG_SYS_NAND_U_BOOT_DST
2808 Location in memory to load U-Boot to
2810 CONFIG_SYS_NAND_U_BOOT_SIZE
2811 Size of image to load
2813 CONFIG_SYS_NAND_U_BOOT_START
2814 Entry point in loaded image to jump to
2816 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2817 Define this if you need to first read the OOB and then the
2818 data. This is used for example on davinci plattforms.
2820 CONFIG_SPL_OMAP3_ID_NAND
2821 Support for an OMAP3-specific set of functions to return the
2822 ID and MFR of the first attached NAND chip, if present.
2824 CONFIG_SPL_SERIAL_SUPPORT
2825 Support for drivers/serial/libserial.o in SPL binary
2827 CONFIG_SPL_SPI_FLASH_SUPPORT
2828 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2830 CONFIG_SPL_SPI_SUPPORT
2831 Support for drivers/spi/libspi.o in SPL binary
2833 CONFIG_SPL_RAM_DEVICE
2834 Support for running image already present in ram, in SPL binary
2836 CONFIG_SPL_LIBGENERIC_SUPPORT
2837 Support for lib/libgeneric.o in SPL binary
2840 Final target image containing SPL and payload. Some SPLs
2841 use an arch-specific makefile fragment instead, for
2842 example if more than one image needs to be produced.
2847 [so far only for SMDK2400 boards]
2849 - Modem support enable:
2850 CONFIG_MODEM_SUPPORT
2852 - RTS/CTS Flow control enable:
2855 - Modem debug support:
2856 CONFIG_MODEM_SUPPORT_DEBUG
2858 Enables debugging stuff (char screen[1024], dbg())
2859 for modem support. Useful only with BDI2000.
2861 - Interrupt support (PPC):
2863 There are common interrupt_init() and timer_interrupt()
2864 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2865 for CPU specific initialization. interrupt_init_cpu()
2866 should set decrementer_count to appropriate value. If
2867 CPU resets decrementer automatically after interrupt
2868 (ppc4xx) it should set decrementer_count to zero.
2869 timer_interrupt() calls timer_interrupt_cpu() for CPU
2870 specific handling. If board has watchdog / status_led
2871 / other_activity_monitor it works automatically from
2872 general timer_interrupt().
2876 In the target system modem support is enabled when a
2877 specific key (key combination) is pressed during
2878 power-on. Otherwise U-Boot will boot normally
2879 (autoboot). The key_pressed() function is called from
2880 board_init(). Currently key_pressed() is a dummy
2881 function, returning 1 and thus enabling modem
2884 If there are no modem init strings in the
2885 environment, U-Boot proceed to autoboot; the
2886 previous output (banner, info printfs) will be
2889 See also: doc/README.Modem
2891 Board initialization settings:
2892 ------------------------------
2894 During Initialization u-boot calls a number of board specific functions
2895 to allow the preparation of board specific prerequisites, e.g. pin setup
2896 before drivers are initialized. To enable these callbacks the
2897 following configuration macros have to be defined. Currently this is
2898 architecture specific, so please check arch/your_architecture/lib/board.c
2899 typically in board_init_f() and board_init_r().
2901 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2902 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2903 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2904 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2906 Configuration Settings:
2907 -----------------------
2909 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2910 undefine this when you're short of memory.
2912 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2913 width of the commands listed in the 'help' command output.
2915 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2916 prompt for user input.
2918 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2920 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2922 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2924 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2925 the application (usually a Linux kernel) when it is
2928 - CONFIG_SYS_BAUDRATE_TABLE:
2929 List of legal baudrate settings for this board.
2931 - CONFIG_SYS_CONSOLE_INFO_QUIET
2932 Suppress display of console information at boot.
2934 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2935 If the board specific function
2936 extern int overwrite_console (void);
2937 returns 1, the stdin, stderr and stdout are switched to the
2938 serial port, else the settings in the environment are used.
2940 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2941 Enable the call to overwrite_console().
2943 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2944 Enable overwrite of previous console environment settings.
2946 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2947 Begin and End addresses of the area used by the
2950 - CONFIG_SYS_ALT_MEMTEST:
2951 Enable an alternate, more extensive memory test.
2953 - CONFIG_SYS_MEMTEST_SCRATCH:
2954 Scratch address used by the alternate memory test
2955 You only need to set this if address zero isn't writeable
2957 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2958 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2959 this specified memory area will get subtracted from the top
2960 (end) of RAM and won't get "touched" at all by U-Boot. By
2961 fixing up gd->ram_size the Linux kernel should gets passed
2962 the now "corrected" memory size and won't touch it either.
2963 This should work for arch/ppc and arch/powerpc. Only Linux
2964 board ports in arch/powerpc with bootwrapper support that
2965 recalculate the memory size from the SDRAM controller setup
2966 will have to get fixed in Linux additionally.
2968 This option can be used as a workaround for the 440EPx/GRx
2969 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2972 WARNING: Please make sure that this value is a multiple of
2973 the Linux page size (normally 4k). If this is not the case,
2974 then the end address of the Linux memory will be located at a
2975 non page size aligned address and this could cause major
2978 - CONFIG_SYS_TFTP_LOADADDR:
2979 Default load address for network file downloads
2981 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2982 Enable temporary baudrate change while serial download
2984 - CONFIG_SYS_SDRAM_BASE:
2985 Physical start address of SDRAM. _Must_ be 0 here.
2987 - CONFIG_SYS_MBIO_BASE:
2988 Physical start address of Motherboard I/O (if using a
2991 - CONFIG_SYS_FLASH_BASE:
2992 Physical start address of Flash memory.
2994 - CONFIG_SYS_MONITOR_BASE:
2995 Physical start address of boot monitor code (set by
2996 make config files to be same as the text base address
2997 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2998 CONFIG_SYS_FLASH_BASE when booting from flash.
3000 - CONFIG_SYS_MONITOR_LEN:
3001 Size of memory reserved for monitor code, used to
3002 determine _at_compile_time_ (!) if the environment is
3003 embedded within the U-Boot image, or in a separate
3006 - CONFIG_SYS_MALLOC_LEN:
3007 Size of DRAM reserved for malloc() use.
3009 - CONFIG_SYS_BOOTM_LEN:
3010 Normally compressed uImages are limited to an
3011 uncompressed size of 8 MBytes. If this is not enough,
3012 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3013 to adjust this setting to your needs.
3015 - CONFIG_SYS_BOOTMAPSZ:
3016 Maximum size of memory mapped by the startup code of
3017 the Linux kernel; all data that must be processed by
3018 the Linux kernel (bd_info, boot arguments, FDT blob if
3019 used) must be put below this limit, unless "bootm_low"
3020 enviroment variable is defined and non-zero. In such case
3021 all data for the Linux kernel must be between "bootm_low"
3022 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3023 variable "bootm_mapsize" will override the value of
3024 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3025 then the value in "bootm_size" will be used instead.
3027 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3028 Enable initrd_high functionality. If defined then the
3029 initrd_high feature is enabled and the bootm ramdisk subcommand
3032 - CONFIG_SYS_BOOT_GET_CMDLINE:
3033 Enables allocating and saving kernel cmdline in space between
3034 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3036 - CONFIG_SYS_BOOT_GET_KBD:
3037 Enables allocating and saving a kernel copy of the bd_info in
3038 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3040 - CONFIG_SYS_MAX_FLASH_BANKS:
3041 Max number of Flash memory banks
3043 - CONFIG_SYS_MAX_FLASH_SECT:
3044 Max number of sectors on a Flash chip
3046 - CONFIG_SYS_FLASH_ERASE_TOUT:
3047 Timeout for Flash erase operations (in ms)
3049 - CONFIG_SYS_FLASH_WRITE_TOUT:
3050 Timeout for Flash write operations (in ms)
3052 - CONFIG_SYS_FLASH_LOCK_TOUT
3053 Timeout for Flash set sector lock bit operation (in ms)
3055 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3056 Timeout for Flash clear lock bits operation (in ms)
3058 - CONFIG_SYS_FLASH_PROTECTION
3059 If defined, hardware flash sectors protection is used
3060 instead of U-Boot software protection.
3062 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3064 Enable TFTP transfers directly to flash memory;
3065 without this option such a download has to be
3066 performed in two steps: (1) download to RAM, and (2)
3067 copy from RAM to flash.
3069 The two-step approach is usually more reliable, since
3070 you can check if the download worked before you erase
3071 the flash, but in some situations (when system RAM is
3072 too limited to allow for a temporary copy of the
3073 downloaded image) this option may be very useful.
3075 - CONFIG_SYS_FLASH_CFI:
3076 Define if the flash driver uses extra elements in the
3077 common flash structure for storing flash geometry.
3079 - CONFIG_FLASH_CFI_DRIVER
3080 This option also enables the building of the cfi_flash driver
3081 in the drivers directory
3083 - CONFIG_FLASH_CFI_MTD
3084 This option enables the building of the cfi_mtd driver
3085 in the drivers directory. The driver exports CFI flash
3088 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3089 Use buffered writes to flash.
3091 - CONFIG_FLASH_SPANSION_S29WS_N
3092 s29ws-n MirrorBit flash has non-standard addresses for buffered
3095 - CONFIG_SYS_FLASH_QUIET_TEST
3096 If this option is defined, the common CFI flash doesn't
3097 print it's warning upon not recognized FLASH banks. This
3098 is useful, if some of the configured banks are only
3099 optionally available.
3101 - CONFIG_FLASH_SHOW_PROGRESS
3102 If defined (must be an integer), print out countdown
3103 digits and dots. Recommended value: 45 (9..1) for 80
3104 column displays, 15 (3..1) for 40 column displays.
3106 - CONFIG_SYS_RX_ETH_BUFFER:
3107 Defines the number of Ethernet receive buffers. On some
3108 Ethernet controllers it is recommended to set this value
3109 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3110 buffers can be full shortly after enabling the interface
3111 on high Ethernet traffic.
3112 Defaults to 4 if not defined.
3114 - CONFIG_ENV_MAX_ENTRIES
3116 Maximum number of entries in the hash table that is used
3117 internally to store the environment settings. The default
3118 setting is supposed to be generous and should work in most
3119 cases. This setting can be used to tune behaviour; see
3120 lib/hashtable.c for details.
3122 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3123 - CONFIG_ENV_FLAGS_LIST_STATIC
3124 Enable validation of the values given to enviroment variables when
3125 calling env set. Variables can be restricted to only decimal,
3126 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3127 the variables can also be restricted to IP address or MAC address.
3129 The format of the list is:
3130 type_attribute = [s|d|x|b|i|m]
3131 attributes = type_attribute
3132 entry = variable_name[:attributes]
3135 The type attributes are:
3136 s - String (default)
3139 b - Boolean ([1yYtT|0nNfF])
3143 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3144 Define this to a list (string) to define the ".flags"
3145 envirnoment variable in the default or embedded environment.
3147 - CONFIG_ENV_FLAGS_LIST_STATIC
3148 Define this to a list (string) to define validation that
3149 should be done if an entry is not found in the ".flags"
3150 environment variable. To override a setting in the static
3151 list, simply add an entry for the same variable name to the
3154 The following definitions that deal with the placement and management
3155 of environment data (variable area); in general, we support the
3156 following configurations:
3158 - CONFIG_BUILD_ENVCRC:
3160 Builds up envcrc with the target environment so that external utils
3161 may easily extract it and embed it in final U-Boot images.
3163 - CONFIG_ENV_IS_IN_FLASH:
3165 Define this if the environment is in flash memory.
3167 a) The environment occupies one whole flash sector, which is
3168 "embedded" in the text segment with the U-Boot code. This
3169 happens usually with "bottom boot sector" or "top boot
3170 sector" type flash chips, which have several smaller
3171 sectors at the start or the end. For instance, such a
3172 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3173 such a case you would place the environment in one of the
3174 4 kB sectors - with U-Boot code before and after it. With
3175 "top boot sector" type flash chips, you would put the
3176 environment in one of the last sectors, leaving a gap
3177 between U-Boot and the environment.
3179 - CONFIG_ENV_OFFSET:
3181 Offset of environment data (variable area) to the
3182 beginning of flash memory; for instance, with bottom boot
3183 type flash chips the second sector can be used: the offset
3184 for this sector is given here.
3186 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3190 This is just another way to specify the start address of
3191 the flash sector containing the environment (instead of
3194 - CONFIG_ENV_SECT_SIZE:
3196 Size of the sector containing the environment.
3199 b) Sometimes flash chips have few, equal sized, BIG sectors.
3200 In such a case you don't want to spend a whole sector for
3205 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3206 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3207 of this flash sector for the environment. This saves
3208 memory for the RAM copy of the environment.
3210 It may also save flash memory if you decide to use this
3211 when your environment is "embedded" within U-Boot code,
3212 since then the remainder of the flash sector could be used
3213 for U-Boot code. It should be pointed out that this is
3214 STRONGLY DISCOURAGED from a robustness point of view:
3215 updating the environment in flash makes it always
3216 necessary to erase the WHOLE sector. If something goes
3217 wrong before the contents has been restored from a copy in
3218 RAM, your target system will be dead.
3220 - CONFIG_ENV_ADDR_REDUND
3221 CONFIG_ENV_SIZE_REDUND
3223 These settings describe a second storage area used to hold
3224 a redundant copy of the environment data, so that there is
3225 a valid backup copy in case there is a power failure during
3226 a "saveenv" operation.
3228 BE CAREFUL! Any changes to the flash layout, and some changes to the
3229 source code will make it necessary to adapt <board>/u-boot.lds*
3233 - CONFIG_ENV_IS_IN_NVRAM:
3235 Define this if you have some non-volatile memory device
3236 (NVRAM, battery buffered SRAM) which you want to use for the
3242 These two #defines are used to determine the memory area you
3243 want to use for environment. It is assumed that this memory
3244 can just be read and written to, without any special
3247 BE CAREFUL! The first access to the environment happens quite early
3248 in U-Boot initalization (when we try to get the setting of for the
3249 console baudrate). You *MUST* have mapped your NVRAM area then, or
3252 Please note that even with NVRAM we still use a copy of the
3253 environment in RAM: we could work on NVRAM directly, but we want to
3254 keep settings there always unmodified except somebody uses "saveenv"
3255 to save the current settings.
3258 - CONFIG_ENV_IS_IN_EEPROM:
3260 Use this if you have an EEPROM or similar serial access
3261 device and a driver for it.
3263 - CONFIG_ENV_OFFSET:
3266 These two #defines specify the offset and size of the
3267 environment area within the total memory of your EEPROM.
3269 - CONFIG_SYS_I2C_EEPROM_ADDR:
3270 If defined, specified the chip address of the EEPROM device.
3271 The default address is zero.
3273 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3274 If defined, the number of bits used to address bytes in a
3275 single page in the EEPROM device. A 64 byte page, for example
3276 would require six bits.
3278 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3279 If defined, the number of milliseconds to delay between
3280 page writes. The default is zero milliseconds.
3282 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3283 The length in bytes of the EEPROM memory array address. Note
3284 that this is NOT the chip address length!
3286 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3287 EEPROM chips that implement "address overflow" are ones
3288 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3289 address and the extra bits end up in the "chip address" bit
3290 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3293 Note that we consider the length of the address field to
3294 still be one byte because the extra address bits are hidden
3295 in the chip address.
3297 - CONFIG_SYS_EEPROM_SIZE:
3298 The size in bytes of the EEPROM device.
3300 - CONFIG_ENV_EEPROM_IS_ON_I2C
3301 define this, if you have I2C and SPI activated, and your
3302 EEPROM, which holds the environment, is on the I2C bus.
3304 - CONFIG_I2C_ENV_EEPROM_BUS
3305 if you have an Environment on an EEPROM reached over
3306 I2C muxes, you can define here, how to reach this
3307 EEPROM. For example:
3309 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3311 EEPROM which holds the environment, is reached over
3312 a pca9547 i2c mux with address 0x70, channel 3.
3314 - CONFIG_ENV_IS_IN_DATAFLASH:
3316 Define this if you have a DataFlash memory device which you
3317 want to use for the environment.
3319 - CONFIG_ENV_OFFSET:
3323 These three #defines specify the offset and size of the
3324 environment area within the total memory of your DataFlash placed
3325 at the specified address.
3327 - CONFIG_ENV_IS_IN_REMOTE:
3329 Define this if you have a remote memory space which you
3330 want to use for the local device's environment.
3335 These two #defines specify the address and size of the
3336 environment area within the remote memory space. The
3337 local device can get the environment from remote memory
3338 space by SRIO or PCIE links.
3340 BE CAREFUL! For some special cases, the local device can not use
3341 "saveenv" command. For example, the local device will get the
3342 environment stored in a remote NOR flash by SRIO or PCIE link,
3343 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3345 - CONFIG_ENV_IS_IN_NAND:
3347 Define this if you have a NAND device which you want to use
3348 for the environment.
3350 - CONFIG_ENV_OFFSET:
3353 These two #defines specify the offset and size of the environment
3354 area within the first NAND device. CONFIG_ENV_OFFSET must be
3355 aligned to an erase block boundary.
3357 - CONFIG_ENV_OFFSET_REDUND (optional):
3359 This setting describes a second storage area of CONFIG_ENV_SIZE
3360 size used to hold a redundant copy of the environment data, so
3361 that there is a valid backup copy in case there is a power failure
3362 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3363 aligned to an erase block boundary.
3365 - CONFIG_ENV_RANGE (optional):
3367 Specifies the length of the region in which the environment
3368 can be written. This should be a multiple of the NAND device's
3369 block size. Specifying a range with more erase blocks than
3370 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3371 the range to be avoided.
3373 - CONFIG_ENV_OFFSET_OOB (optional):
3375 Enables support for dynamically retrieving the offset of the
3376 environment from block zero's out-of-band data. The
3377 "nand env.oob" command can be used to record this offset.
3378 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3379 using CONFIG_ENV_OFFSET_OOB.
3381 - CONFIG_NAND_ENV_DST
3383 Defines address in RAM to which the nand_spl code should copy the
3384 environment. If redundant environment is used, it will be copied to
3385 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3387 - CONFIG_SYS_SPI_INIT_OFFSET
3389 Defines offset to the initial SPI buffer area in DPRAM. The
3390 area is used at an early stage (ROM part) if the environment
3391 is configured to reside in the SPI EEPROM: We need a 520 byte
3392 scratch DPRAM area. It is used between the two initialization
3393 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3394 to be a good choice since it makes it far enough from the
3395 start of the data area as well as from the stack pointer.
3397 Please note that the environment is read-only until the monitor
3398 has been relocated to RAM and a RAM copy of the environment has been
3399 created; also, when using EEPROM you will have to use getenv_f()
3400 until then to read environment variables.
3402 The environment is protected by a CRC32 checksum. Before the monitor
3403 is relocated into RAM, as a result of a bad CRC you will be working
3404 with the compiled-in default environment - *silently*!!! [This is
3405 necessary, because the first environment variable we need is the
3406 "baudrate" setting for the console - if we have a bad CRC, we don't
3407 have any device yet where we could complain.]
3409 Note: once the monitor has been relocated, then it will complain if
3410 the default environment is used; a new CRC is computed as soon as you
3411 use the "saveenv" command to store a valid environment.
3413 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3414 Echo the inverted Ethernet link state to the fault LED.
3416 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3417 also needs to be defined.
3419 - CONFIG_SYS_FAULT_MII_ADDR:
3420 MII address of the PHY to check for the Ethernet link state.
3422 - CONFIG_NS16550_MIN_FUNCTIONS:
3423 Define this if you desire to only have use of the NS16550_init
3424 and NS16550_putc functions for the serial driver located at
3425 drivers/serial/ns16550.c. This option is useful for saving
3426 space for already greatly restricted images, including but not
3427 limited to NAND_SPL configurations.
3429 Low Level (hardware related) configuration options:
3430 ---------------------------------------------------
3432 - CONFIG_SYS_CACHELINE_SIZE:
3433 Cache Line Size of the CPU.
3435 - CONFIG_SYS_DEFAULT_IMMR:
3436 Default address of the IMMR after system reset.
3438 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3439 and RPXsuper) to be able to adjust the position of
3440 the IMMR register after a reset.
3442 - CONFIG_SYS_CCSRBAR_DEFAULT:
3443 Default (power-on reset) physical address of CCSR on Freescale
3446 - CONFIG_SYS_CCSRBAR:
3447 Virtual address of CCSR. On a 32-bit build, this is typically
3448 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3450 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3451 for cross-platform code that uses that macro instead.
3453 - CONFIG_SYS_CCSRBAR_PHYS:
3454 Physical address of CCSR. CCSR can be relocated to a new
3455 physical address, if desired. In this case, this macro should
3456 be set to that address. Otherwise, it should be set to the
3457 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3458 is typically relocated on 36-bit builds. It is recommended
3459 that this macro be defined via the _HIGH and _LOW macros:
3461 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3462 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3464 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3465 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3466 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3467 used in assembly code, so it must not contain typecasts or
3468 integer size suffixes (e.g. "ULL").
3470 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3471 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3472 used in assembly code, so it must not contain typecasts or
3473 integer size suffixes (e.g. "ULL").
3475 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3476 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3477 forced to a value that ensures that CCSR is not relocated.
3479 - Floppy Disk Support:
3480 CONFIG_SYS_FDC_DRIVE_NUMBER
3482 the default drive number (default value 0)
3484 CONFIG_SYS_ISA_IO_STRIDE
3486 defines the spacing between FDC chipset registers
3489 CONFIG_SYS_ISA_IO_OFFSET
3491 defines the offset of register from address. It
3492 depends on which part of the data bus is connected to
3493 the FDC chipset. (default value 0)
3495 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3496 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3499 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3500 fdc_hw_init() is called at the beginning of the FDC
3501 setup. fdc_hw_init() must be provided by the board
3502 source code. It is used to make hardware dependant
3506 Most IDE controllers were designed to be connected with PCI
3507 interface. Only few of them were designed for AHB interface.
3508 When software is doing ATA command and data transfer to
3509 IDE devices through IDE-AHB controller, some additional
3510 registers accessing to these kind of IDE-AHB controller
3513 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3514 DO NOT CHANGE unless you know exactly what you're
3515 doing! (11-4) [MPC8xx/82xx systems only]
3517 - CONFIG_SYS_INIT_RAM_ADDR:
3519 Start address of memory area that can be used for
3520 initial data and stack; please note that this must be
3521 writable memory that is working WITHOUT special
3522 initialization, i. e. you CANNOT use normal RAM which
3523 will become available only after programming the
3524 memory controller and running certain initialization
3527 U-Boot uses the following memory types:
3528 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3529 - MPC824X: data cache
3530 - PPC4xx: data cache
3532 - CONFIG_SYS_GBL_DATA_OFFSET:
3534 Offset of the initial data structure in the memory
3535 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3536 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3537 data is located at the end of the available space
3538 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3539 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3540 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3541 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3544 On the MPC824X (or other systems that use the data
3545 cache for initial memory) the address chosen for
3546 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3547 point to an otherwise UNUSED address space between
3548 the top of RAM and the start of the PCI space.
3550 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3552 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3554 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3556 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3558 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3560 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3562 - CONFIG_SYS_OR_TIMING_SDRAM:
3565 - CONFIG_SYS_MAMR_PTA:
3566 periodic timer for refresh
3568 - CONFIG_SYS_DER: Debug Event Register (37-47)
3570 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3571 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3572 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3573 CONFIG_SYS_BR1_PRELIM:
3574 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3576 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3577 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3578 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3579 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3581 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3582 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3583 Machine Mode Register and Memory Periodic Timer
3584 Prescaler definitions (SDRAM timing)
3586 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3587 enable I2C microcode relocation patch (MPC8xx);
3588 define relocation offset in DPRAM [DSP2]
3590 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3591 enable SMC microcode relocation patch (MPC8xx);
3592 define relocation offset in DPRAM [SMC1]
3594 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3595 enable SPI microcode relocation patch (MPC8xx);
3596 define relocation offset in DPRAM [SCC4]
3598 - CONFIG_SYS_USE_OSCCLK:
3599 Use OSCM clock mode on MBX8xx board. Be careful,
3600 wrong setting might damage your board. Read
3601 doc/README.MBX before setting this variable!
3603 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3604 Offset of the bootmode word in DPRAM used by post
3605 (Power On Self Tests). This definition overrides
3606 #define'd default value in commproc.h resp.
3609 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3610 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3611 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3612 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3613 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3614 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3615 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3616 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3617 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3619 - CONFIG_PCI_DISABLE_PCIE:
3620 Disable PCI-Express on systems where it is supported but not
3623 - CONFIG_PCI_ENUM_ONLY
3624 Only scan through and get the devices on the busses.
3625 Don't do any setup work, presumably because someone or
3626 something has already done it, and we don't need to do it
3627 a second time. Useful for platforms that are pre-booted
3628 by coreboot or similar.
3631 Chip has SRIO or not
3634 Board has SRIO 1 port available
3637 Board has SRIO 2 port available
3639 - CONFIG_SYS_SRIOn_MEM_VIRT:
3640 Virtual Address of SRIO port 'n' memory region
3642 - CONFIG_SYS_SRIOn_MEM_PHYS:
3643 Physical Address of SRIO port 'n' memory region
3645 - CONFIG_SYS_SRIOn_MEM_SIZE:
3646 Size of SRIO port 'n' memory region
3648 - CONFIG_SYS_NDFC_16
3649 Defined to tell the NDFC that the NAND chip is using a
3652 - CONFIG_SYS_NDFC_EBC0_CFG
3653 Sets the EBC0_CFG register for the NDFC. If not defined
3654 a default value will be used.
3657 Get DDR timing information from an I2C EEPROM. Common
3658 with pluggable memory modules such as SODIMMs
3661 I2C address of the SPD EEPROM
3663 - CONFIG_SYS_SPD_BUS_NUM
3664 If SPD EEPROM is on an I2C bus other than the first
3665 one, specify here. Note that the value must resolve
3666 to something your driver can deal with.
3668 - CONFIG_SYS_DDR_RAW_TIMING
3669 Get DDR timing information from other than SPD. Common with
3670 soldered DDR chips onboard without SPD. DDR raw timing
3671 parameters are extracted from datasheet and hard-coded into
3672 header files or board specific files.
3674 - CONFIG_FSL_DDR_INTERACTIVE
3675 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3677 - CONFIG_SYS_83XX_DDR_USES_CS0
3678 Only for 83xx systems. If specified, then DDR should
3679 be configured using CS0 and CS1 instead of CS2 and CS3.
3681 - CONFIG_ETHER_ON_FEC[12]
3682 Define to enable FEC[12] on a 8xx series processor.
3684 - CONFIG_FEC[12]_PHY
3685 Define to the hardcoded PHY address which corresponds
3686 to the given FEC; i. e.
3687 #define CONFIG_FEC1_PHY 4
3688 means that the PHY with address 4 is connected to FEC1
3690 When set to -1, means to probe for first available.
3692 - CONFIG_FEC[12]_PHY_NORXERR
3693 The PHY does not have a RXERR line (RMII only).
3694 (so program the FEC to ignore it).
3697 Enable RMII mode for all FECs.
3698 Note that this is a global option, we can't
3699 have one FEC in standard MII mode and another in RMII mode.
3701 - CONFIG_CRC32_VERIFY
3702 Add a verify option to the crc32 command.
3705 => crc32 -v <address> <count> <crc32>
3707 Where address/count indicate a memory area
3708 and crc32 is the correct crc32 which the
3712 Add the "loopw" memory command. This only takes effect if
3713 the memory commands are activated globally (CONFIG_CMD_MEM).
3716 Add the "mdc" and "mwc" memory commands. These are cyclic
3721 This command will print 4 bytes (10,11,12,13) each 500 ms.
3723 => mwc.l 100 12345678 10
3724 This command will write 12345678 to address 100 all 10 ms.
3726 This only takes effect if the memory commands are activated
3727 globally (CONFIG_CMD_MEM).
3729 - CONFIG_SKIP_LOWLEVEL_INIT
3730 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3731 low level initializations (like setting up the memory
3732 controller) are omitted and/or U-Boot does not
3733 relocate itself into RAM.
3735 Normally this variable MUST NOT be defined. The only
3736 exception is when U-Boot is loaded (to RAM) by some
3737 other boot loader or by a debugger which performs
3738 these initializations itself.
3741 Modifies the behaviour of start.S when compiling a loader
3742 that is executed before the actual U-Boot. E.g. when
3743 compiling a NAND SPL.
3745 - CONFIG_USE_ARCH_MEMCPY
3746 CONFIG_USE_ARCH_MEMSET
3747 If these options are used a optimized version of memcpy/memset will
3748 be used if available. These functions may be faster under some
3749 conditions but may increase the binary size.
3751 - CONFIG_X86_NO_RESET_VECTOR
3752 If defined, the x86 reset vector code is excluded. You will need
3753 to do this when U-Boot is running from Coreboot.
3755 - CONFIG_X86_NO_REAL_MODE
3756 If defined, x86 real mode code is omitted. This assumes a
3757 32-bit environment where such code is not needed. You will
3758 need to do this when U-Boot is running from Coreboot.
3761 Freescale QE/FMAN Firmware Support:
3762 -----------------------------------
3764 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3765 loading of "firmware", which is encoded in the QE firmware binary format.
3766 This firmware often needs to be loaded during U-Boot booting, so macros
3767 are used to identify the storage device (NOR flash, SPI, etc) and the address
3770 - CONFIG_SYS_QE_FMAN_FW_ADDR
3771 The address in the storage device where the firmware is located. The
3772 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3775 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3776 The maximum possible size of the firmware. The firmware binary format
3777 has a field that specifies the actual size of the firmware, but it
3778 might not be possible to read any part of the firmware unless some
3779 local storage is allocated to hold the entire firmware first.
3781 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3782 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3783 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3784 virtual address in NOR flash.
3786 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3787 Specifies that QE/FMAN firmware is located in NAND flash.
3788 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3790 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3791 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3792 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3794 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3795 Specifies that QE/FMAN firmware is located on the primary SPI
3796 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3798 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3799 Specifies that QE/FMAN firmware is located in the remote (master)
3800 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3801 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3802 window->master inbound window->master LAW->the ucode address in
3803 master's memory space.
3805 Building the Software:
3806 ======================
3808 Building U-Boot has been tested in several native build environments
3809 and in many different cross environments. Of course we cannot support
3810 all possibly existing versions of cross development tools in all
3811 (potentially obsolete) versions. In case of tool chain problems we
3812 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3813 which is extensively used to build and test U-Boot.
3815 If you are not using a native environment, it is assumed that you
3816 have GNU cross compiling tools available in your path. In this case,
3817 you must set the environment variable CROSS_COMPILE in your shell.
3818 Note that no changes to the Makefile or any other source files are
3819 necessary. For example using the ELDK on a 4xx CPU, please enter:
3821 $ CROSS_COMPILE=ppc_4xx-
3822 $ export CROSS_COMPILE
3824 Note: If you wish to generate Windows versions of the utilities in
3825 the tools directory you can use the MinGW toolchain
3826 (http://www.mingw.org). Set your HOST tools to the MinGW
3827 toolchain and execute 'make tools'. For example:
3829 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3831 Binaries such as tools/mkimage.exe will be created which can
3832 be executed on computers running Windows.
3834 U-Boot is intended to be simple to build. After installing the
3835 sources you must configure U-Boot for one specific board type. This
3840 where "NAME_config" is the name of one of the existing configu-
3841 rations; see boards.cfg for supported names.
3843 Note: for some board special configuration names may exist; check if
3844 additional information is available from the board vendor; for
3845 instance, the TQM823L systems are available without (standard)
3846 or with LCD support. You can select such additional "features"
3847 when choosing the configuration, i. e.
3850 - will configure for a plain TQM823L, i. e. no LCD support
3852 make TQM823L_LCD_config
3853 - will configure for a TQM823L with U-Boot console on LCD
3858 Finally, type "make all", and you should get some working U-Boot
3859 images ready for download to / installation on your system:
3861 - "u-boot.bin" is a raw binary image
3862 - "u-boot" is an image in ELF binary format
3863 - "u-boot.srec" is in Motorola S-Record format
3865 By default the build is performed locally and the objects are saved
3866 in the source directory. One of the two methods can be used to change
3867 this behavior and build U-Boot to some external directory:
3869 1. Add O= to the make command line invocations:
3871 make O=/tmp/build distclean
3872 make O=/tmp/build NAME_config
3873 make O=/tmp/build all
3875 2. Set environment variable BUILD_DIR to point to the desired location:
3877 export BUILD_DIR=/tmp/build
3882 Note that the command line "O=" setting overrides the BUILD_DIR environment
3886 Please be aware that the Makefiles assume you are using GNU make, so
3887 for instance on NetBSD you might need to use "gmake" instead of
3891 If the system board that you have is not listed, then you will need
3892 to port U-Boot to your hardware platform. To do this, follow these
3895 1. Add a new configuration option for your board to the toplevel
3896 "boards.cfg" file, using the existing entries as examples.
3897 Follow the instructions there to keep the boards in order.
3898 2. Create a new directory to hold your board specific code. Add any
3899 files you need. In your board directory, you will need at least
3900 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3901 3. Create a new configuration file "include/configs/<board>.h" for
3903 3. If you're porting U-Boot to a new CPU, then also create a new
3904 directory to hold your CPU specific code. Add any files you need.
3905 4. Run "make <board>_config" with your new name.
3906 5. Type "make", and you should get a working "u-boot.srec" file
3907 to be installed on your target system.
3908 6. Debug and solve any problems that might arise.
3909 [Of course, this last step is much harder than it sounds.]
3912 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3913 ==============================================================
3915 If you have modified U-Boot sources (for instance added a new board
3916 or support for new devices, a new CPU, etc.) you are expected to
3917 provide feedback to the other developers. The feedback normally takes
3918 the form of a "patch", i. e. a context diff against a certain (latest
3919 official or latest in the git repository) version of U-Boot sources.
3921 But before you submit such a patch, please verify that your modifi-
3922 cation did not break existing code. At least make sure that *ALL* of
3923 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3924 just run the "MAKEALL" script, which will configure and build U-Boot
3925 for ALL supported system. Be warned, this will take a while. You can
3926 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3927 environment variable to the script, i. e. to use the ELDK cross tools
3930 CROSS_COMPILE=ppc_8xx- MAKEALL
3932 or to build on a native PowerPC system you can type
3934 CROSS_COMPILE=' ' MAKEALL
3936 When using the MAKEALL script, the default behaviour is to build
3937 U-Boot in the source directory. This location can be changed by
3938 setting the BUILD_DIR environment variable. Also, for each target
3939 built, the MAKEALL script saves two log files (<target>.ERR and
3940 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3941 location can be changed by setting the MAKEALL_LOGDIR environment
3942 variable. For example:
3944 export BUILD_DIR=/tmp/build
3945 export MAKEALL_LOGDIR=/tmp/log
3946 CROSS_COMPILE=ppc_8xx- MAKEALL
3948 With the above settings build objects are saved in the /tmp/build,
3949 log files are saved in the /tmp/log and the source tree remains clean
3950 during the whole build process.
3953 See also "U-Boot Porting Guide" below.
3956 Monitor Commands - Overview:
3957 ============================
3959 go - start application at address 'addr'
3960 run - run commands in an environment variable
3961 bootm - boot application image from memory
3962 bootp - boot image via network using BootP/TFTP protocol
3963 bootz - boot zImage from memory
3964 tftpboot- boot image via network using TFTP protocol
3965 and env variables "ipaddr" and "serverip"
3966 (and eventually "gatewayip")
3967 tftpput - upload a file via network using TFTP protocol
3968 rarpboot- boot image via network using RARP/TFTP protocol
3969 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3970 loads - load S-Record file over serial line
3971 loadb - load binary file over serial line (kermit mode)
3973 mm - memory modify (auto-incrementing)
3974 nm - memory modify (constant address)
3975 mw - memory write (fill)
3977 cmp - memory compare
3978 crc32 - checksum calculation
3979 i2c - I2C sub-system
3980 sspi - SPI utility commands
3981 base - print or set address offset
3982 printenv- print environment variables
3983 setenv - set environment variables
3984 saveenv - save environment variables to persistent storage
3985 protect - enable or disable FLASH write protection
3986 erase - erase FLASH memory
3987 flinfo - print FLASH memory information
3988 nand - NAND memory operations (see doc/README.nand)
3989 bdinfo - print Board Info structure
3990 iminfo - print header information for application image
3991 coninfo - print console devices and informations
3992 ide - IDE sub-system
3993 loop - infinite loop on address range
3994 loopw - infinite write loop on address range
3995 mtest - simple RAM test
3996 icache - enable or disable instruction cache
3997 dcache - enable or disable data cache
3998 reset - Perform RESET of the CPU
3999 echo - echo args to console
4000 version - print monitor version
4001 help - print online help
4002 ? - alias for 'help'
4005 Monitor Commands - Detailed Description:
4006 ========================================
4010 For now: just type "help <command>".
4013 Environment Variables:
4014 ======================
4016 U-Boot supports user configuration using Environment Variables which
4017 can be made persistent by saving to Flash memory.
4019 Environment Variables are set using "setenv", printed using
4020 "printenv", and saved to Flash using "saveenv". Using "setenv"
4021 without a value can be used to delete a variable from the
4022 environment. As long as you don't save the environment you are
4023 working with an in-memory copy. In case the Flash area containing the
4024 environment is erased by accident, a default environment is provided.
4026 Some configuration options can be set using Environment Variables.
4028 List of environment variables (most likely not complete):
4030 baudrate - see CONFIG_BAUDRATE
4032 bootdelay - see CONFIG_BOOTDELAY
4034 bootcmd - see CONFIG_BOOTCOMMAND
4036 bootargs - Boot arguments when booting an RTOS image
4038 bootfile - Name of the image to load with TFTP
4040 bootm_low - Memory range available for image processing in the bootm
4041 command can be restricted. This variable is given as
4042 a hexadecimal number and defines lowest address allowed
4043 for use by the bootm command. See also "bootm_size"
4044 environment variable. Address defined by "bootm_low" is
4045 also the base of the initial memory mapping for the Linux
4046 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4049 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4050 This variable is given as a hexadecimal number and it
4051 defines the size of the memory region starting at base
4052 address bootm_low that is accessible by the Linux kernel
4053 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4054 as the default value if it is defined, and bootm_size is
4057 bootm_size - Memory range available for image processing in the bootm
4058 command can be restricted. This variable is given as
4059 a hexadecimal number and defines the size of the region
4060 allowed for use by the bootm command. See also "bootm_low"
4061 environment variable.
4063 updatefile - Location of the software update file on a TFTP server, used
4064 by the automatic software update feature. Please refer to
4065 documentation in doc/README.update for more details.
4067 autoload - if set to "no" (any string beginning with 'n'),
4068 "bootp" will just load perform a lookup of the
4069 configuration from the BOOTP server, but not try to
4070 load any image using TFTP
4072 autostart - if set to "yes", an image loaded using the "bootp",
4073 "rarpboot", "tftpboot" or "diskboot" commands will
4074 be automatically started (by internally calling
4077 If set to "no", a standalone image passed to the
4078 "bootm" command will be copied to the load address
4079 (and eventually uncompressed), but NOT be started.
4080 This can be used to load and uncompress arbitrary
4083 fdt_high - if set this restricts the maximum address that the
4084 flattened device tree will be copied into upon boot.
4085 For example, if you have a system with 1 GB memory
4086 at physical address 0x10000000, while Linux kernel
4087 only recognizes the first 704 MB as low memory, you
4088 may need to set fdt_high as 0x3C000000 to have the
4089 device tree blob be copied to the maximum address
4090 of the 704 MB low memory, so that Linux kernel can
4091 access it during the boot procedure.
4093 If this is set to the special value 0xFFFFFFFF then
4094 the fdt will not be copied at all on boot. For this
4095 to work it must reside in writable memory, have
4096 sufficient padding on the end of it for u-boot to
4097 add the information it needs into it, and the memory
4098 must be accessible by the kernel.
4100 fdtcontroladdr- if set this is the address of the control flattened
4101 device tree used by U-Boot when CONFIG_OF_CONTROL is
4104 i2cfast - (PPC405GP|PPC405EP only)
4105 if set to 'y' configures Linux I2C driver for fast
4106 mode (400kHZ). This environment variable is used in
4107 initialization code. So, for changes to be effective
4108 it must be saved and board must be reset.
4110 initrd_high - restrict positioning of initrd images:
4111 If this variable is not set, initrd images will be
4112 copied to the highest possible address in RAM; this
4113 is usually what you want since it allows for
4114 maximum initrd size. If for some reason you want to
4115 make sure that the initrd image is loaded below the
4116 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4117 variable to a value of "no" or "off" or "0".
4118 Alternatively, you can set it to a maximum upper
4119 address to use (U-Boot will still check that it
4120 does not overwrite the U-Boot stack and data).
4122 For instance, when you have a system with 16 MB
4123 RAM, and want to reserve 4 MB from use by Linux,
4124 you can do this by adding "mem=12M" to the value of
4125 the "bootargs" variable. However, now you must make
4126 sure that the initrd image is placed in the first
4127 12 MB as well - this can be done with
4129 setenv initrd_high 00c00000
4131 If you set initrd_high to 0xFFFFFFFF, this is an
4132 indication to U-Boot that all addresses are legal
4133 for the Linux kernel, including addresses in flash
4134 memory. In this case U-Boot will NOT COPY the
4135 ramdisk at all. This may be useful to reduce the
4136 boot time on your system, but requires that this
4137 feature is supported by your Linux kernel.
4139 ipaddr - IP address; needed for tftpboot command
4141 loadaddr - Default load address for commands like "bootp",
4142 "rarpboot", "tftpboot", "loadb" or "diskboot"
4144 loads_echo - see CONFIG_LOADS_ECHO
4146 serverip - TFTP server IP address; needed for tftpboot command
4148 bootretry - see CONFIG_BOOT_RETRY_TIME
4150 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4152 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4154 ethprime - controls which interface is used first.
4156 ethact - controls which interface is currently active.
4157 For example you can do the following
4159 => setenv ethact FEC
4160 => ping 192.168.0.1 # traffic sent on FEC
4161 => setenv ethact SCC
4162 => ping 10.0.0.1 # traffic sent on SCC
4164 ethrotate - When set to "no" U-Boot does not go through all
4165 available network interfaces.
4166 It just stays at the currently selected interface.
4168 netretry - When set to "no" each network operation will
4169 either succeed or fail without retrying.
4170 When set to "once" the network operation will
4171 fail when all the available network interfaces
4172 are tried once without success.
4173 Useful on scripts which control the retry operation
4176 npe_ucode - set load address for the NPE microcode
4178 tftpsrcport - If this is set, the value is used for TFTP's
4181 tftpdstport - If this is set, the value is used for TFTP's UDP
4182 destination port instead of the Well Know Port 69.
4184 tftpblocksize - Block size to use for TFTP transfers; if not set,
4185 we use the TFTP server's default block size
4187 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4188 seconds, minimum value is 1000 = 1 second). Defines
4189 when a packet is considered to be lost so it has to
4190 be retransmitted. The default is 5000 = 5 seconds.
4191 Lowering this value may make downloads succeed
4192 faster in networks with high packet loss rates or
4193 with unreliable TFTP servers.
4195 vlan - When set to a value < 4095 the traffic over
4196 Ethernet is encapsulated/received over 802.1q
4199 The following image location variables contain the location of images
4200 used in booting. The "Image" column gives the role of the image and is
4201 not an environment variable name. The other columns are environment
4202 variable names. "File Name" gives the name of the file on a TFTP
4203 server, "RAM Address" gives the location in RAM the image will be
4204 loaded to, and "Flash Location" gives the image's address in NOR
4205 flash or offset in NAND flash.
4207 *Note* - these variables don't have to be defined for all boards, some
4208 boards currenlty use other variables for these purposes, and some
4209 boards use these variables for other purposes.
4211 Image File Name RAM Address Flash Location
4212 ----- --------- ----------- --------------
4213 u-boot u-boot u-boot_addr_r u-boot_addr
4214 Linux kernel bootfile kernel_addr_r kernel_addr
4215 device tree blob fdtfile fdt_addr_r fdt_addr
4216 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4218 The following environment variables may be used and automatically
4219 updated by the network boot commands ("bootp" and "rarpboot"),
4220 depending the information provided by your boot server:
4222 bootfile - see above
4223 dnsip - IP address of your Domain Name Server
4224 dnsip2 - IP address of your secondary Domain Name Server
4225 gatewayip - IP address of the Gateway (Router) to use
4226 hostname - Target hostname
4228 netmask - Subnet Mask
4229 rootpath - Pathname of the root filesystem on the NFS server
4230 serverip - see above
4233 There are two special Environment Variables:
4235 serial# - contains hardware identification information such
4236 as type string and/or serial number
4237 ethaddr - Ethernet address
4239 These variables can be set only once (usually during manufacturing of
4240 the board). U-Boot refuses to delete or overwrite these variables
4241 once they have been set once.
4244 Further special Environment Variables:
4246 ver - Contains the U-Boot version string as printed
4247 with the "version" command. This variable is
4248 readonly (see CONFIG_VERSION_VARIABLE).
4251 Please note that changes to some configuration parameters may take
4252 only effect after the next boot (yes, that's just like Windoze :-).
4255 Callback functions for environment variables:
4256 ---------------------------------------------
4258 For some environment variables, the behavior of u-boot needs to change
4259 when their values are changed. This functionailty allows functions to
4260 be associated with arbitrary variables. On creation, overwrite, or
4261 deletion, the callback will provide the opportunity for some side
4262 effect to happen or for the change to be rejected.
4264 The callbacks are named and associated with a function using the
4265 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4267 These callbacks are associated with variables in one of two ways. The
4268 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4269 in the board configuration to a string that defines a list of
4270 associations. The list must be in the following format:
4272 entry = variable_name[:callback_name]
4275 If the callback name is not specified, then the callback is deleted.
4276 Spaces are also allowed anywhere in the list.
4278 Callbacks can also be associated by defining the ".callbacks" variable
4279 with the same list format above. Any association in ".callbacks" will
4280 override any association in the static list. You can define
4281 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4282 ".callbacks" envirnoment variable in the default or embedded environment.
4285 Command Line Parsing:
4286 =====================
4288 There are two different command line parsers available with U-Boot:
4289 the old "simple" one, and the much more powerful "hush" shell:
4291 Old, simple command line parser:
4292 --------------------------------
4294 - supports environment variables (through setenv / saveenv commands)
4295 - several commands on one line, separated by ';'
4296 - variable substitution using "... ${name} ..." syntax
4297 - special characters ('$', ';') can be escaped by prefixing with '\',
4299 setenv bootcmd bootm \${address}
4300 - You can also escape text by enclosing in single apostrophes, for example:
4301 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4306 - similar to Bourne shell, with control structures like
4307 if...then...else...fi, for...do...done; while...do...done,
4308 until...do...done, ...
4309 - supports environment ("global") variables (through setenv / saveenv
4310 commands) and local shell variables (through standard shell syntax
4311 "name=value"); only environment variables can be used with "run"
4317 (1) If a command line (or an environment variable executed by a "run"
4318 command) contains several commands separated by semicolon, and
4319 one of these commands fails, then the remaining commands will be
4322 (2) If you execute several variables with one call to run (i. e.
4323 calling run with a list of variables as arguments), any failing
4324 command will cause "run" to terminate, i. e. the remaining
4325 variables are not executed.
4327 Note for Redundant Ethernet Interfaces:
4328 =======================================
4330 Some boards come with redundant Ethernet interfaces; U-Boot supports
4331 such configurations and is capable of automatic selection of a
4332 "working" interface when needed. MAC assignment works as follows:
4334 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4335 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4336 "eth1addr" (=>eth1), "eth2addr", ...
4338 If the network interface stores some valid MAC address (for instance
4339 in SROM), this is used as default address if there is NO correspon-
4340 ding setting in the environment; if the corresponding environment
4341 variable is set, this overrides the settings in the card; that means:
4343 o If the SROM has a valid MAC address, and there is no address in the
4344 environment, the SROM's address is used.
4346 o If there is no valid address in the SROM, and a definition in the
4347 environment exists, then the value from the environment variable is
4350 o If both the SROM and the environment contain a MAC address, and
4351 both addresses are the same, this MAC address is used.
4353 o If both the SROM and the environment contain a MAC address, and the
4354 addresses differ, the value from the environment is used and a
4357 o If neither SROM nor the environment contain a MAC address, an error
4360 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4361 will be programmed into hardware as part of the initialization process. This
4362 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4363 The naming convention is as follows:
4364 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4369 U-Boot is capable of booting (and performing other auxiliary operations on)
4370 images in two formats:
4372 New uImage format (FIT)
4373 -----------------------
4375 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4376 to Flattened Device Tree). It allows the use of images with multiple
4377 components (several kernels, ramdisks, etc.), with contents protected by
4378 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4384 Old image format is based on binary files which can be basically anything,
4385 preceded by a special header; see the definitions in include/image.h for
4386 details; basically, the header defines the following image properties:
4388 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4389 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4390 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4391 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4393 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4394 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4395 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4396 * Compression Type (uncompressed, gzip, bzip2)
4402 The header is marked by a special Magic Number, and both the header
4403 and the data portions of the image are secured against corruption by
4410 Although U-Boot should support any OS or standalone application
4411 easily, the main focus has always been on Linux during the design of
4414 U-Boot includes many features that so far have been part of some
4415 special "boot loader" code within the Linux kernel. Also, any
4416 "initrd" images to be used are no longer part of one big Linux image;
4417 instead, kernel and "initrd" are separate images. This implementation
4418 serves several purposes:
4420 - the same features can be used for other OS or standalone
4421 applications (for instance: using compressed images to reduce the
4422 Flash memory footprint)
4424 - it becomes much easier to port new Linux kernel versions because
4425 lots of low-level, hardware dependent stuff are done by U-Boot
4427 - the same Linux kernel image can now be used with different "initrd"
4428 images; of course this also means that different kernel images can
4429 be run with the same "initrd". This makes testing easier (you don't
4430 have to build a new "zImage.initrd" Linux image when you just
4431 change a file in your "initrd"). Also, a field-upgrade of the
4432 software is easier now.
4438 Porting Linux to U-Boot based systems:
4439 ---------------------------------------
4441 U-Boot cannot save you from doing all the necessary modifications to
4442 configure the Linux device drivers for use with your target hardware
4443 (no, we don't intend to provide a full virtual machine interface to
4446 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4448 Just make sure your machine specific header file (for instance
4449 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4450 Information structure as we define in include/asm-<arch>/u-boot.h,
4451 and make sure that your definition of IMAP_ADDR uses the same value
4452 as your U-Boot configuration in CONFIG_SYS_IMMR.
4455 Configuring the Linux kernel:
4456 -----------------------------
4458 No specific requirements for U-Boot. Make sure you have some root
4459 device (initial ramdisk, NFS) for your target system.
4462 Building a Linux Image:
4463 -----------------------
4465 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4466 not used. If you use recent kernel source, a new build target
4467 "uImage" will exist which automatically builds an image usable by
4468 U-Boot. Most older kernels also have support for a "pImage" target,
4469 which was introduced for our predecessor project PPCBoot and uses a
4470 100% compatible format.
4479 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4480 encapsulate a compressed Linux kernel image with header information,
4481 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4483 * build a standard "vmlinux" kernel image (in ELF binary format):
4485 * convert the kernel into a raw binary image:
4487 ${CROSS_COMPILE}-objcopy -O binary \
4488 -R .note -R .comment \
4489 -S vmlinux linux.bin
4491 * compress the binary image:
4495 * package compressed binary image for U-Boot:
4497 mkimage -A ppc -O linux -T kernel -C gzip \
4498 -a 0 -e 0 -n "Linux Kernel Image" \
4499 -d linux.bin.gz uImage
4502 The "mkimage" tool can also be used to create ramdisk images for use
4503 with U-Boot, either separated from the Linux kernel image, or
4504 combined into one file. "mkimage" encapsulates the images with a 64
4505 byte header containing information about target architecture,
4506 operating system, image type, compression method, entry points, time
4507 stamp, CRC32 checksums, etc.
4509 "mkimage" can be called in two ways: to verify existing images and
4510 print the header information, or to build new images.
4512 In the first form (with "-l" option) mkimage lists the information
4513 contained in the header of an existing U-Boot image; this includes
4514 checksum verification:
4516 tools/mkimage -l image
4517 -l ==> list image header information
4519 The second form (with "-d" option) is used to build a U-Boot image
4520 from a "data file" which is used as image payload:
4522 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4523 -n name -d data_file image
4524 -A ==> set architecture to 'arch'
4525 -O ==> set operating system to 'os'
4526 -T ==> set image type to 'type'
4527 -C ==> set compression type 'comp'
4528 -a ==> set load address to 'addr' (hex)
4529 -e ==> set entry point to 'ep' (hex)
4530 -n ==> set image name to 'name'
4531 -d ==> use image data from 'datafile'
4533 Right now, all Linux kernels for PowerPC systems use the same load
4534 address (0x00000000), but the entry point address depends on the
4537 - 2.2.x kernels have the entry point at 0x0000000C,
4538 - 2.3.x and later kernels have the entry point at 0x00000000.
4540 So a typical call to build a U-Boot image would read:
4542 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4543 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4544 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4545 > examples/uImage.TQM850L
4546 Image Name: 2.4.4 kernel for TQM850L
4547 Created: Wed Jul 19 02:34:59 2000
4548 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4549 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4550 Load Address: 0x00000000
4551 Entry Point: 0x00000000
4553 To verify the contents of the image (or check for corruption):
4555 -> tools/mkimage -l examples/uImage.TQM850L
4556 Image Name: 2.4.4 kernel for TQM850L
4557 Created: Wed Jul 19 02:34:59 2000
4558 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4559 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4560 Load Address: 0x00000000
4561 Entry Point: 0x00000000
4563 NOTE: for embedded systems where boot time is critical you can trade
4564 speed for memory and install an UNCOMPRESSED image instead: this
4565 needs more space in Flash, but boots much faster since it does not
4566 need to be uncompressed:
4568 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4569 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4570 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4571 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4572 > examples/uImage.TQM850L-uncompressed
4573 Image Name: 2.4.4 kernel for TQM850L
4574 Created: Wed Jul 19 02:34:59 2000
4575 Image Type: PowerPC Linux Kernel Image (uncompressed)
4576 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4577 Load Address: 0x00000000
4578 Entry Point: 0x00000000
4581 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4582 when your kernel is intended to use an initial ramdisk:
4584 -> tools/mkimage -n 'Simple Ramdisk Image' \
4585 > -A ppc -O linux -T ramdisk -C gzip \
4586 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4587 Image Name: Simple Ramdisk Image
4588 Created: Wed Jan 12 14:01:50 2000
4589 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4590 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4591 Load Address: 0x00000000
4592 Entry Point: 0x00000000
4595 Installing a Linux Image:
4596 -------------------------
4598 To downloading a U-Boot image over the serial (console) interface,
4599 you must convert the image to S-Record format:
4601 objcopy -I binary -O srec examples/image examples/image.srec
4603 The 'objcopy' does not understand the information in the U-Boot
4604 image header, so the resulting S-Record file will be relative to
4605 address 0x00000000. To load it to a given address, you need to
4606 specify the target address as 'offset' parameter with the 'loads'
4609 Example: install the image to address 0x40100000 (which on the
4610 TQM8xxL is in the first Flash bank):
4612 => erase 40100000 401FFFFF
4618 ## Ready for S-Record download ...
4619 ~>examples/image.srec
4620 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4622 15989 15990 15991 15992
4623 [file transfer complete]
4625 ## Start Addr = 0x00000000
4628 You can check the success of the download using the 'iminfo' command;
4629 this includes a checksum verification so you can be sure no data
4630 corruption happened:
4634 ## Checking Image at 40100000 ...
4635 Image Name: 2.2.13 for initrd on TQM850L
4636 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4637 Data Size: 335725 Bytes = 327 kB = 0 MB
4638 Load Address: 00000000
4639 Entry Point: 0000000c
4640 Verifying Checksum ... OK
4646 The "bootm" command is used to boot an application that is stored in
4647 memory (RAM or Flash). In case of a Linux kernel image, the contents
4648 of the "bootargs" environment variable is passed to the kernel as
4649 parameters. You can check and modify this variable using the
4650 "printenv" and "setenv" commands:
4653 => printenv bootargs
4654 bootargs=root=/dev/ram
4656 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4658 => printenv bootargs
4659 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4662 ## Booting Linux kernel at 40020000 ...
4663 Image Name: 2.2.13 for NFS on TQM850L
4664 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4665 Data Size: 381681 Bytes = 372 kB = 0 MB
4666 Load Address: 00000000
4667 Entry Point: 0000000c
4668 Verifying Checksum ... OK
4669 Uncompressing Kernel Image ... OK
4670 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
4671 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4672 time_init: decrementer frequency = 187500000/60
4673 Calibrating delay loop... 49.77 BogoMIPS
4674 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4677 If you want to boot a Linux kernel with initial RAM disk, you pass
4678 the memory addresses of both the kernel and the initrd image (PPBCOOT
4679 format!) to the "bootm" command:
4681 => imi 40100000 40200000
4683 ## Checking Image at 40100000 ...
4684 Image Name: 2.2.13 for initrd on TQM850L
4685 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4686 Data Size: 335725 Bytes = 327 kB = 0 MB
4687 Load Address: 00000000
4688 Entry Point: 0000000c
4689 Verifying Checksum ... OK
4691 ## Checking Image at 40200000 ...
4692 Image Name: Simple Ramdisk Image
4693 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4694 Data Size: 566530 Bytes = 553 kB = 0 MB
4695 Load Address: 00000000
4696 Entry Point: 00000000
4697 Verifying Checksum ... OK
4699 => bootm 40100000 40200000
4700 ## Booting Linux kernel at 40100000 ...
4701 Image Name: 2.2.13 for initrd on TQM850L
4702 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4703 Data Size: 335725 Bytes = 327 kB = 0 MB
4704 Load Address: 00000000
4705 Entry Point: 0000000c
4706 Verifying Checksum ... OK
4707 Uncompressing Kernel Image ... OK
4708 ## Loading RAMDisk Image at 40200000 ...
4709 Image Name: Simple Ramdisk Image
4710 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4711 Data Size: 566530 Bytes = 553 kB = 0 MB
4712 Load Address: 00000000
4713 Entry Point: 00000000
4714 Verifying Checksum ... OK
4715 Loading Ramdisk ... OK
4716 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
4717 Boot arguments: root=/dev/ram
4718 time_init: decrementer frequency = 187500000/60
4719 Calibrating delay loop... 49.77 BogoMIPS
4721 RAMDISK: Compressed image found at block 0
4722 VFS: Mounted root (ext2 filesystem).
4726 Boot Linux and pass a flat device tree:
4729 First, U-Boot must be compiled with the appropriate defines. See the section
4730 titled "Linux Kernel Interface" above for a more in depth explanation. The
4731 following is an example of how to start a kernel and pass an updated
4737 oft=oftrees/mpc8540ads.dtb
4738 => tftp $oftaddr $oft
4739 Speed: 1000, full duplex
4741 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4742 Filename 'oftrees/mpc8540ads.dtb'.
4743 Load address: 0x300000
4746 Bytes transferred = 4106 (100a hex)
4747 => tftp $loadaddr $bootfile
4748 Speed: 1000, full duplex
4750 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4752 Load address: 0x200000
4753 Loading:############
4755 Bytes transferred = 1029407 (fb51f hex)
4760 => bootm $loadaddr - $oftaddr
4761 ## Booting image at 00200000 ...
4762 Image Name: Linux-2.6.17-dirty
4763 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4764 Data Size: 1029343 Bytes = 1005.2 kB
4765 Load Address: 00000000
4766 Entry Point: 00000000
4767 Verifying Checksum ... OK
4768 Uncompressing Kernel Image ... OK
4769 Booting using flat device tree at 0x300000
4770 Using MPC85xx ADS machine description
4771 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4775 More About U-Boot Image Types:
4776 ------------------------------
4778 U-Boot supports the following image types:
4780 "Standalone Programs" are directly runnable in the environment
4781 provided by U-Boot; it is expected that (if they behave
4782 well) you can continue to work in U-Boot after return from
4783 the Standalone Program.
4784 "OS Kernel Images" are usually images of some Embedded OS which
4785 will take over control completely. Usually these programs
4786 will install their own set of exception handlers, device
4787 drivers, set up the MMU, etc. - this means, that you cannot
4788 expect to re-enter U-Boot except by resetting the CPU.
4789 "RAMDisk Images" are more or less just data blocks, and their
4790 parameters (address, size) are passed to an OS kernel that is
4792 "Multi-File Images" contain several images, typically an OS
4793 (Linux) kernel image and one or more data images like
4794 RAMDisks. This construct is useful for instance when you want
4795 to boot over the network using BOOTP etc., where the boot
4796 server provides just a single image file, but you want to get
4797 for instance an OS kernel and a RAMDisk image.
4799 "Multi-File Images" start with a list of image sizes, each
4800 image size (in bytes) specified by an "uint32_t" in network
4801 byte order. This list is terminated by an "(uint32_t)0".
4802 Immediately after the terminating 0 follow the images, one by
4803 one, all aligned on "uint32_t" boundaries (size rounded up to
4804 a multiple of 4 bytes).
4806 "Firmware Images" are binary images containing firmware (like
4807 U-Boot or FPGA images) which usually will be programmed to
4810 "Script files" are command sequences that will be executed by
4811 U-Boot's command interpreter; this feature is especially
4812 useful when you configure U-Boot to use a real shell (hush)
4813 as command interpreter.
4815 Booting the Linux zImage:
4816 -------------------------
4818 On some platforms, it's possible to boot Linux zImage. This is done
4819 using the "bootz" command. The syntax of "bootz" command is the same
4820 as the syntax of "bootm" command.
4822 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4823 kernel with raw initrd images. The syntax is slightly different, the
4824 address of the initrd must be augmented by it's size, in the following
4825 format: "<initrd addres>:<initrd size>".
4831 One of the features of U-Boot is that you can dynamically load and
4832 run "standalone" applications, which can use some resources of
4833 U-Boot like console I/O functions or interrupt services.
4835 Two simple examples are included with the sources:
4840 'examples/hello_world.c' contains a small "Hello World" Demo
4841 application; it is automatically compiled when you build U-Boot.
4842 It's configured to run at address 0x00040004, so you can play with it
4846 ## Ready for S-Record download ...
4847 ~>examples/hello_world.srec
4848 1 2 3 4 5 6 7 8 9 10 11 ...
4849 [file transfer complete]
4851 ## Start Addr = 0x00040004
4853 => go 40004 Hello World! This is a test.
4854 ## Starting application at 0x00040004 ...
4865 Hit any key to exit ...
4867 ## Application terminated, rc = 0x0
4869 Another example, which demonstrates how to register a CPM interrupt
4870 handler with the U-Boot code, can be found in 'examples/timer.c'.
4871 Here, a CPM timer is set up to generate an interrupt every second.
4872 The interrupt service routine is trivial, just printing a '.'
4873 character, but this is just a demo program. The application can be
4874 controlled by the following keys:
4876 ? - print current values og the CPM Timer registers
4877 b - enable interrupts and start timer
4878 e - stop timer and disable interrupts
4879 q - quit application
4882 ## Ready for S-Record download ...
4883 ~>examples/timer.srec
4884 1 2 3 4 5 6 7 8 9 10 11 ...
4885 [file transfer complete]
4887 ## Start Addr = 0x00040004
4890 ## Starting application at 0x00040004 ...
4893 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4896 [q, b, e, ?] Set interval 1000000 us
4899 [q, b, e, ?] ........
4900 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4903 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4906 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4909 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4911 [q, b, e, ?] ...Stopping timer
4913 [q, b, e, ?] ## Application terminated, rc = 0x0
4919 Over time, many people have reported problems when trying to use the
4920 "minicom" terminal emulation program for serial download. I (wd)
4921 consider minicom to be broken, and recommend not to use it. Under
4922 Unix, I recommend to use C-Kermit for general purpose use (and
4923 especially for kermit binary protocol download ("loadb" command), and
4924 use "cu" for S-Record download ("loads" command). See
4925 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4926 for help with kermit.
4929 Nevertheless, if you absolutely want to use it try adding this
4930 configuration to your "File transfer protocols" section:
4932 Name Program Name U/D FullScr IO-Red. Multi
4933 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4934 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4940 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4941 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4943 Building requires a cross environment; it is known to work on
4944 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4945 need gmake since the Makefiles are not compatible with BSD make).
4946 Note that the cross-powerpc package does not install include files;
4947 attempting to build U-Boot will fail because <machine/ansi.h> is
4948 missing. This file has to be installed and patched manually:
4950 # cd /usr/pkg/cross/powerpc-netbsd/include
4952 # ln -s powerpc machine
4953 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4954 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4956 Native builds *don't* work due to incompatibilities between native
4957 and U-Boot include files.
4959 Booting assumes that (the first part of) the image booted is a
4960 stage-2 loader which in turn loads and then invokes the kernel
4961 proper. Loader sources will eventually appear in the NetBSD source
4962 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4963 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4966 Implementation Internals:
4967 =========================
4969 The following is not intended to be a complete description of every
4970 implementation detail. However, it should help to understand the
4971 inner workings of U-Boot and make it easier to port it to custom
4975 Initial Stack, Global Data:
4976 ---------------------------
4978 The implementation of U-Boot is complicated by the fact that U-Boot
4979 starts running out of ROM (flash memory), usually without access to
4980 system RAM (because the memory controller is not initialized yet).
4981 This means that we don't have writable Data or BSS segments, and BSS
4982 is not initialized as zero. To be able to get a C environment working
4983 at all, we have to allocate at least a minimal stack. Implementation
4984 options for this are defined and restricted by the CPU used: Some CPU
4985 models provide on-chip memory (like the IMMR area on MPC8xx and
4986 MPC826x processors), on others (parts of) the data cache can be
4987 locked as (mis-) used as memory, etc.
4989 Chris Hallinan posted a good summary of these issues to the
4990 U-Boot mailing list:
4992 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4993 From: "Chris Hallinan" <clh@net1plus.com>
4994 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4997 Correct me if I'm wrong, folks, but the way I understand it
4998 is this: Using DCACHE as initial RAM for Stack, etc, does not
4999 require any physical RAM backing up the cache. The cleverness
5000 is that the cache is being used as a temporary supply of
5001 necessary storage before the SDRAM controller is setup. It's
5002 beyond the scope of this list to explain the details, but you
5003 can see how this works by studying the cache architecture and
5004 operation in the architecture and processor-specific manuals.
5006 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5007 is another option for the system designer to use as an
5008 initial stack/RAM area prior to SDRAM being available. Either
5009 option should work for you. Using CS 4 should be fine if your
5010 board designers haven't used it for something that would
5011 cause you grief during the initial boot! It is frequently not
5014 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5015 with your processor/board/system design. The default value
5016 you will find in any recent u-boot distribution in
5017 walnut.h should work for you. I'd set it to a value larger
5018 than your SDRAM module. If you have a 64MB SDRAM module, set
5019 it above 400_0000. Just make sure your board has no resources
5020 that are supposed to respond to that address! That code in
5021 start.S has been around a while and should work as is when
5022 you get the config right.
5027 It is essential to remember this, since it has some impact on the C
5028 code for the initialization procedures:
5030 * Initialized global data (data segment) is read-only. Do not attempt
5033 * Do not use any uninitialized global data (or implicitely initialized
5034 as zero data - BSS segment) at all - this is undefined, initiali-
5035 zation is performed later (when relocating to RAM).
5037 * Stack space is very limited. Avoid big data buffers or things like
5040 Having only the stack as writable memory limits means we cannot use
5041 normal global data to share information beween the code. But it
5042 turned out that the implementation of U-Boot can be greatly
5043 simplified by making a global data structure (gd_t) available to all
5044 functions. We could pass a pointer to this data as argument to _all_
5045 functions, but this would bloat the code. Instead we use a feature of
5046 the GCC compiler (Global Register Variables) to share the data: we
5047 place a pointer (gd) to the global data into a register which we
5048 reserve for this purpose.
5050 When choosing a register for such a purpose we are restricted by the
5051 relevant (E)ABI specifications for the current architecture, and by
5052 GCC's implementation.
5054 For PowerPC, the following registers have specific use:
5056 R2: reserved for system use
5057 R3-R4: parameter passing and return values
5058 R5-R10: parameter passing
5059 R13: small data area pointer
5063 (U-Boot also uses R12 as internal GOT pointer. r12
5064 is a volatile register so r12 needs to be reset when
5065 going back and forth between asm and C)
5067 ==> U-Boot will use R2 to hold a pointer to the global data
5069 Note: on PPC, we could use a static initializer (since the
5070 address of the global data structure is known at compile time),
5071 but it turned out that reserving a register results in somewhat
5072 smaller code - although the code savings are not that big (on
5073 average for all boards 752 bytes for the whole U-Boot image,
5074 624 text + 127 data).
5076 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5077 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5079 ==> U-Boot will use P3 to hold a pointer to the global data
5081 On ARM, the following registers are used:
5083 R0: function argument word/integer result
5084 R1-R3: function argument word
5086 R10: stack limit (used only if stack checking if enabled)
5087 R11: argument (frame) pointer
5088 R12: temporary workspace
5091 R15: program counter
5093 ==> U-Boot will use R8 to hold a pointer to the global data
5095 On Nios II, the ABI is documented here:
5096 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5098 ==> U-Boot will use gp to hold a pointer to the global data
5100 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5101 to access small data sections, so gp is free.
5103 On NDS32, the following registers are used:
5105 R0-R1: argument/return
5107 R15: temporary register for assembler
5108 R16: trampoline register
5109 R28: frame pointer (FP)
5110 R29: global pointer (GP)
5111 R30: link register (LP)
5112 R31: stack pointer (SP)
5113 PC: program counter (PC)
5115 ==> U-Boot will use R10 to hold a pointer to the global data
5117 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5118 or current versions of GCC may "optimize" the code too much.
5123 U-Boot runs in system state and uses physical addresses, i.e. the
5124 MMU is not used either for address mapping nor for memory protection.
5126 The available memory is mapped to fixed addresses using the memory
5127 controller. In this process, a contiguous block is formed for each
5128 memory type (Flash, SDRAM, SRAM), even when it consists of several
5129 physical memory banks.
5131 U-Boot is installed in the first 128 kB of the first Flash bank (on
5132 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5133 booting and sizing and initializing DRAM, the code relocates itself
5134 to the upper end of DRAM. Immediately below the U-Boot code some
5135 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5136 configuration setting]. Below that, a structure with global Board
5137 Info data is placed, followed by the stack (growing downward).
5139 Additionally, some exception handler code is copied to the low 8 kB
5140 of DRAM (0x00000000 ... 0x00001FFF).
5142 So a typical memory configuration with 16 MB of DRAM could look like
5145 0x0000 0000 Exception Vector code
5148 0x0000 2000 Free for Application Use
5154 0x00FB FF20 Monitor Stack (Growing downward)
5155 0x00FB FFAC Board Info Data and permanent copy of global data
5156 0x00FC 0000 Malloc Arena
5159 0x00FE 0000 RAM Copy of Monitor Code
5160 ... eventually: LCD or video framebuffer
5161 ... eventually: pRAM (Protected RAM - unchanged by reset)
5162 0x00FF FFFF [End of RAM]
5165 System Initialization:
5166 ----------------------
5168 In the reset configuration, U-Boot starts at the reset entry point
5169 (on most PowerPC systems at address 0x00000100). Because of the reset
5170 configuration for CS0# this is a mirror of the onboard Flash memory.
5171 To be able to re-map memory U-Boot then jumps to its link address.
5172 To be able to implement the initialization code in C, a (small!)
5173 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5174 which provide such a feature like MPC8xx or MPC8260), or in a locked
5175 part of the data cache. After that, U-Boot initializes the CPU core,
5176 the caches and the SIU.
5178 Next, all (potentially) available memory banks are mapped using a
5179 preliminary mapping. For example, we put them on 512 MB boundaries
5180 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5181 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5182 programmed for SDRAM access. Using the temporary configuration, a
5183 simple memory test is run that determines the size of the SDRAM
5186 When there is more than one SDRAM bank, and the banks are of
5187 different size, the largest is mapped first. For equal size, the first
5188 bank (CS2#) is mapped first. The first mapping is always for address
5189 0x00000000, with any additional banks following immediately to create
5190 contiguous memory starting from 0.
5192 Then, the monitor installs itself at the upper end of the SDRAM area
5193 and allocates memory for use by malloc() and for the global Board
5194 Info data; also, the exception vector code is copied to the low RAM
5195 pages, and the final stack is set up.
5197 Only after this relocation will you have a "normal" C environment;
5198 until that you are restricted in several ways, mostly because you are
5199 running from ROM, and because the code will have to be relocated to a
5203 U-Boot Porting Guide:
5204 ----------------------
5206 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5210 int main(int argc, char *argv[])
5212 sighandler_t no_more_time;
5214 signal(SIGALRM, no_more_time);
5215 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5217 if (available_money > available_manpower) {
5218 Pay consultant to port U-Boot;
5222 Download latest U-Boot source;
5224 Subscribe to u-boot mailing list;
5227 email("Hi, I am new to U-Boot, how do I get started?");
5230 Read the README file in the top level directory;
5231 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5232 Read applicable doc/*.README;
5233 Read the source, Luke;
5234 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5237 if (available_money > toLocalCurrency ($2500))
5240 Add a lot of aggravation and time;
5242 if (a similar board exists) { /* hopefully... */
5243 cp -a board/<similar> board/<myboard>
5244 cp include/configs/<similar>.h include/configs/<myboard>.h
5246 Create your own board support subdirectory;
5247 Create your own board include/configs/<myboard>.h file;
5249 Edit new board/<myboard> files
5250 Edit new include/configs/<myboard>.h
5255 Add / modify source code;
5259 email("Hi, I am having problems...");
5261 Send patch file to the U-Boot email list;
5262 if (reasonable critiques)
5263 Incorporate improvements from email list code review;
5265 Defend code as written;
5271 void no_more_time (int sig)
5280 All contributions to U-Boot should conform to the Linux kernel
5281 coding style; see the file "Documentation/CodingStyle" and the script
5282 "scripts/Lindent" in your Linux kernel source directory.
5284 Source files originating from a different project (for example the
5285 MTD subsystem) are generally exempt from these guidelines and are not
5286 reformated to ease subsequent migration to newer versions of those
5289 Please note that U-Boot is implemented in C (and to some small parts in
5290 Assembler); no C++ is used, so please do not use C++ style comments (//)
5293 Please also stick to the following formatting rules:
5294 - remove any trailing white space
5295 - use TAB characters for indentation and vertical alignment, not spaces
5296 - make sure NOT to use DOS '\r\n' line feeds
5297 - do not add more than 2 consecutive empty lines to source files
5298 - do not add trailing empty lines to source files
5300 Submissions which do not conform to the standards may be returned
5301 with a request to reformat the changes.
5307 Since the number of patches for U-Boot is growing, we need to
5308 establish some rules. Submissions which do not conform to these rules
5309 may be rejected, even when they contain important and valuable stuff.
5311 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5313 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5314 see http://lists.denx.de/mailman/listinfo/u-boot
5316 When you send a patch, please include the following information with
5319 * For bug fixes: a description of the bug and how your patch fixes
5320 this bug. Please try to include a way of demonstrating that the
5321 patch actually fixes something.
5323 * For new features: a description of the feature and your
5326 * A CHANGELOG entry as plaintext (separate from the patch)
5328 * For major contributions, your entry to the CREDITS file
5330 * When you add support for a new board, don't forget to add this
5331 board to the MAINTAINERS file, too.
5333 * If your patch adds new configuration options, don't forget to
5334 document these in the README file.
5336 * The patch itself. If you are using git (which is *strongly*
5337 recommended) you can easily generate the patch using the
5338 "git format-patch". If you then use "git send-email" to send it to
5339 the U-Boot mailing list, you will avoid most of the common problems
5340 with some other mail clients.
5342 If you cannot use git, use "diff -purN OLD NEW". If your version of
5343 diff does not support these options, then get the latest version of
5346 The current directory when running this command shall be the parent
5347 directory of the U-Boot source tree (i. e. please make sure that
5348 your patch includes sufficient directory information for the
5351 We prefer patches as plain text. MIME attachments are discouraged,
5352 and compressed attachments must not be used.
5354 * If one logical set of modifications affects or creates several
5355 files, all these changes shall be submitted in a SINGLE patch file.
5357 * Changesets that contain different, unrelated modifications shall be
5358 submitted as SEPARATE patches, one patch per changeset.
5363 * Before sending the patch, run the MAKEALL script on your patched
5364 source tree and make sure that no errors or warnings are reported
5365 for any of the boards.
5367 * Keep your modifications to the necessary minimum: A patch
5368 containing several unrelated changes or arbitrary reformats will be
5369 returned with a request to re-formatting / split it.
5371 * If you modify existing code, make sure that your new code does not
5372 add to the memory footprint of the code ;-) Small is beautiful!
5373 When adding new features, these should compile conditionally only
5374 (using #ifdef), and the resulting code with the new feature
5375 disabled must not need more memory than the old code without your
5378 * Remember that there is a size limit of 100 kB per message on the
5379 u-boot mailing list. Bigger patches will be moderated. If they are
5380 reasonable and not too big, they will be acknowledged. But patches
5381 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob