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.
1489 CONFIG_LCD_ALIGNMENT
1491 Normally the LCD is page-aligned (tyically 4KB). If this is
1492 defined then the LCD will be aligned to this value instead.
1493 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1494 here, since it is cheaper to change data cache settings on
1495 a per-section basis.
1497 CONFIG_CONSOLE_SCROLL_LINES
1499 When the console need to be scrolled, this is the number of
1500 lines to scroll by. It defaults to 1. Increasing this makes
1501 the console jump but can help speed up operation when scrolling
1506 Support drawing of RLE8-compressed bitmaps on the LCD.
1510 Enables an 'i2c edid' command which can read EDID
1511 information over I2C from an attached LCD display.
1513 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1515 If this option is set, the environment is checked for
1516 a variable "splashimage". If found, the usual display
1517 of logo, copyright and system information on the LCD
1518 is suppressed and the BMP image at the address
1519 specified in "splashimage" is loaded instead. The
1520 console is redirected to the "nulldev", too. This
1521 allows for a "silent" boot where a splash screen is
1522 loaded very quickly after power-on.
1524 CONFIG_SPLASH_SCREEN_ALIGN
1526 If this option is set the splash image can be freely positioned
1527 on the screen. Environment variable "splashpos" specifies the
1528 position as "x,y". If a positive number is given it is used as
1529 number of pixel from left/top. If a negative number is given it
1530 is used as number of pixel from right/bottom. You can also
1531 specify 'm' for centering the image.
1534 setenv splashpos m,m
1535 => image at center of screen
1537 setenv splashpos 30,20
1538 => image at x = 30 and y = 20
1540 setenv splashpos -10,m
1541 => vertically centered image
1542 at x = dspWidth - bmpWidth - 9
1544 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1546 If this option is set, additionally to standard BMP
1547 images, gzipped BMP images can be displayed via the
1548 splashscreen support or the bmp command.
1550 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1552 If this option is set, 8-bit RLE compressed BMP images
1553 can be displayed via the splashscreen support or the
1556 - Do compresssing for memory range:
1559 If this option is set, it would use zlib deflate method
1560 to compress the specified memory at its best effort.
1562 - Compression support:
1565 If this option is set, support for bzip2 compressed
1566 images is included. If not, only uncompressed and gzip
1567 compressed images are supported.
1569 NOTE: the bzip2 algorithm requires a lot of RAM, so
1570 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1575 If this option is set, support for lzma compressed
1578 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1579 requires an amount of dynamic memory that is given by the
1582 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1584 Where lc and lp stand for, respectively, Literal context bits
1585 and Literal pos bits.
1587 This value is upper-bounded by 14MB in the worst case. Anyway,
1588 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1589 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1590 a very small buffer.
1592 Use the lzmainfo tool to determinate the lc and lp values and
1593 then calculate the amount of needed dynamic memory (ensuring
1594 the appropriate CONFIG_SYS_MALLOC_LEN value).
1599 The address of PHY on MII bus.
1601 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1603 The clock frequency of the MII bus
1607 If this option is set, support for speed/duplex
1608 detection of gigabit PHY is included.
1610 CONFIG_PHY_RESET_DELAY
1612 Some PHY like Intel LXT971A need extra delay after
1613 reset before any MII register access is possible.
1614 For such PHY, set this option to the usec delay
1615 required. (minimum 300usec for LXT971A)
1617 CONFIG_PHY_CMD_DELAY (ppc4xx)
1619 Some PHY like Intel LXT971A need extra delay after
1620 command issued before MII status register can be read
1630 Define a default value for Ethernet address to use
1631 for the respective Ethernet interface, in case this
1632 is not determined automatically.
1637 Define a default value for the IP address to use for
1638 the default Ethernet interface, in case this is not
1639 determined through e.g. bootp.
1640 (Environment variable "ipaddr")
1642 - Server IP address:
1645 Defines a default value for the IP address of a TFTP
1646 server to contact when using the "tftboot" command.
1647 (Environment variable "serverip")
1649 CONFIG_KEEP_SERVERADDR
1651 Keeps the server's MAC address, in the env 'serveraddr'
1652 for passing to bootargs (like Linux's netconsole option)
1654 - Gateway IP address:
1657 Defines a default value for the IP address of the
1658 default router where packets to other networks are
1660 (Environment variable "gatewayip")
1665 Defines a default value for the subnet mask (or
1666 routing prefix) which is used to determine if an IP
1667 address belongs to the local subnet or needs to be
1668 forwarded through a router.
1669 (Environment variable "netmask")
1671 - Multicast TFTP Mode:
1674 Defines whether you want to support multicast TFTP as per
1675 rfc-2090; for example to work with atftp. Lets lots of targets
1676 tftp down the same boot image concurrently. Note: the Ethernet
1677 driver in use must provide a function: mcast() to join/leave a
1680 - BOOTP Recovery Mode:
1681 CONFIG_BOOTP_RANDOM_DELAY
1683 If you have many targets in a network that try to
1684 boot using BOOTP, you may want to avoid that all
1685 systems send out BOOTP requests at precisely the same
1686 moment (which would happen for instance at recovery
1687 from a power failure, when all systems will try to
1688 boot, thus flooding the BOOTP server. Defining
1689 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1690 inserted before sending out BOOTP requests. The
1691 following delays are inserted then:
1693 1st BOOTP request: delay 0 ... 1 sec
1694 2nd BOOTP request: delay 0 ... 2 sec
1695 3rd BOOTP request: delay 0 ... 4 sec
1697 BOOTP requests: delay 0 ... 8 sec
1699 - DHCP Advanced Options:
1700 You can fine tune the DHCP functionality by defining
1701 CONFIG_BOOTP_* symbols:
1703 CONFIG_BOOTP_SUBNETMASK
1704 CONFIG_BOOTP_GATEWAY
1705 CONFIG_BOOTP_HOSTNAME
1706 CONFIG_BOOTP_NISDOMAIN
1707 CONFIG_BOOTP_BOOTPATH
1708 CONFIG_BOOTP_BOOTFILESIZE
1711 CONFIG_BOOTP_SEND_HOSTNAME
1712 CONFIG_BOOTP_NTPSERVER
1713 CONFIG_BOOTP_TIMEOFFSET
1714 CONFIG_BOOTP_VENDOREX
1715 CONFIG_BOOTP_MAY_FAIL
1717 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1718 environment variable, not the BOOTP server.
1720 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1721 after the configured retry count, the call will fail
1722 instead of starting over. This can be used to fail over
1723 to Link-local IP address configuration if the DHCP server
1726 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1727 serverip from a DHCP server, it is possible that more
1728 than one DNS serverip is offered to the client.
1729 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1730 serverip will be stored in the additional environment
1731 variable "dnsip2". The first DNS serverip is always
1732 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1735 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1736 to do a dynamic update of a DNS server. To do this, they
1737 need the hostname of the DHCP requester.
1738 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1739 of the "hostname" environment variable is passed as
1740 option 12 to the DHCP server.
1742 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1744 A 32bit value in microseconds for a delay between
1745 receiving a "DHCP Offer" and sending the "DHCP Request".
1746 This fixes a problem with certain DHCP servers that don't
1747 respond 100% of the time to a "DHCP request". E.g. On an
1748 AT91RM9200 processor running at 180MHz, this delay needed
1749 to be *at least* 15,000 usec before a Windows Server 2003
1750 DHCP server would reply 100% of the time. I recommend at
1751 least 50,000 usec to be safe. The alternative is to hope
1752 that one of the retries will be successful but note that
1753 the DHCP timeout and retry process takes a longer than
1756 - Link-local IP address negotiation:
1757 Negotiate with other link-local clients on the local network
1758 for an address that doesn't require explicit configuration.
1759 This is especially useful if a DHCP server cannot be guaranteed
1760 to exist in all environments that the device must operate.
1762 See doc/README.link-local for more information.
1765 CONFIG_CDP_DEVICE_ID
1767 The device id used in CDP trigger frames.
1769 CONFIG_CDP_DEVICE_ID_PREFIX
1771 A two character string which is prefixed to the MAC address
1776 A printf format string which contains the ascii name of
1777 the port. Normally is set to "eth%d" which sets
1778 eth0 for the first Ethernet, eth1 for the second etc.
1780 CONFIG_CDP_CAPABILITIES
1782 A 32bit integer which indicates the device capabilities;
1783 0x00000010 for a normal host which does not forwards.
1787 An ascii string containing the version of the software.
1791 An ascii string containing the name of the platform.
1795 A 32bit integer sent on the trigger.
1797 CONFIG_CDP_POWER_CONSUMPTION
1799 A 16bit integer containing the power consumption of the
1800 device in .1 of milliwatts.
1802 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1804 A byte containing the id of the VLAN.
1806 - Status LED: CONFIG_STATUS_LED
1808 Several configurations allow to display the current
1809 status using a LED. For instance, the LED will blink
1810 fast while running U-Boot code, stop blinking as
1811 soon as a reply to a BOOTP request was received, and
1812 start blinking slow once the Linux kernel is running
1813 (supported by a status LED driver in the Linux
1814 kernel). Defining CONFIG_STATUS_LED enables this
1817 - CAN Support: CONFIG_CAN_DRIVER
1819 Defining CONFIG_CAN_DRIVER enables CAN driver support
1820 on those systems that support this (optional)
1821 feature, like the TQM8xxL modules.
1823 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1825 These enable I2C serial bus commands. Defining either of
1826 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1827 include the appropriate I2C driver for the selected CPU.
1829 This will allow you to use i2c commands at the u-boot
1830 command line (as long as you set CONFIG_CMD_I2C in
1831 CONFIG_COMMANDS) and communicate with i2c based realtime
1832 clock chips. See common/cmd_i2c.c for a description of the
1833 command line interface.
1835 CONFIG_HARD_I2C selects a hardware I2C controller.
1837 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1838 bit-banging) driver instead of CPM or similar hardware
1841 There are several other quantities that must also be
1842 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1844 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1845 to be the frequency (in Hz) at which you wish your i2c bus
1846 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1847 the CPU's i2c node address).
1849 Now, the u-boot i2c code for the mpc8xx
1850 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1851 and so its address should therefore be cleared to 0 (See,
1852 eg, MPC823e User's Manual p.16-473). So, set
1853 CONFIG_SYS_I2C_SLAVE to 0.
1855 CONFIG_SYS_I2C_INIT_MPC5XXX
1857 When a board is reset during an i2c bus transfer
1858 chips might think that the current transfer is still
1859 in progress. Reset the slave devices by sending start
1860 commands until the slave device responds.
1862 That's all that's required for CONFIG_HARD_I2C.
1864 If you use the software i2c interface (CONFIG_SOFT_I2C)
1865 then the following macros need to be defined (examples are
1866 from include/configs/lwmon.h):
1870 (Optional). Any commands necessary to enable the I2C
1871 controller or configure ports.
1873 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1877 (Only for MPC8260 CPU). The I/O port to use (the code
1878 assumes both bits are on the same port). Valid values
1879 are 0..3 for ports A..D.
1883 The code necessary to make the I2C data line active
1884 (driven). If the data line is open collector, this
1887 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1891 The code necessary to make the I2C data line tri-stated
1892 (inactive). If the data line is open collector, this
1895 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1899 Code that returns TRUE if the I2C data line is high,
1902 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1906 If <bit> is TRUE, sets the I2C data line high. If it
1907 is FALSE, it clears it (low).
1909 eg: #define I2C_SDA(bit) \
1910 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1911 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1915 If <bit> is TRUE, sets the I2C clock line high. If it
1916 is FALSE, it clears it (low).
1918 eg: #define I2C_SCL(bit) \
1919 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1920 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1924 This delay is invoked four times per clock cycle so this
1925 controls the rate of data transfer. The data rate thus
1926 is 1 / (I2C_DELAY * 4). Often defined to be something
1929 #define I2C_DELAY udelay(2)
1931 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1933 If your arch supports the generic GPIO framework (asm/gpio.h),
1934 then you may alternatively define the two GPIOs that are to be
1935 used as SCL / SDA. Any of the previous I2C_xxx macros will
1936 have GPIO-based defaults assigned to them as appropriate.
1938 You should define these to the GPIO value as given directly to
1939 the generic GPIO functions.
1941 CONFIG_SYS_I2C_INIT_BOARD
1943 When a board is reset during an i2c bus transfer
1944 chips might think that the current transfer is still
1945 in progress. On some boards it is possible to access
1946 the i2c SCLK line directly, either by using the
1947 processor pin as a GPIO or by having a second pin
1948 connected to the bus. If this option is defined a
1949 custom i2c_init_board() routine in boards/xxx/board.c
1950 is run early in the boot sequence.
1952 CONFIG_SYS_I2C_BOARD_LATE_INIT
1954 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1955 defined a custom i2c_board_late_init() routine in
1956 boards/xxx/board.c is run AFTER the operations in i2c_init()
1957 is completed. This callpoint can be used to unreset i2c bus
1958 using CPU i2c controller register accesses for CPUs whose i2c
1959 controller provide such a method. It is called at the end of
1960 i2c_init() to allow i2c_init operations to setup the i2c bus
1961 controller on the CPU (e.g. setting bus speed & slave address).
1963 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1965 This option enables configuration of bi_iic_fast[] flags
1966 in u-boot bd_info structure based on u-boot environment
1967 variable "i2cfast". (see also i2cfast)
1969 CONFIG_I2C_MULTI_BUS
1971 This option allows the use of multiple I2C buses, each of which
1972 must have a controller. At any point in time, only one bus is
1973 active. To switch to a different bus, use the 'i2c dev' command.
1974 Note that bus numbering is zero-based.
1976 CONFIG_SYS_I2C_NOPROBES
1978 This option specifies a list of I2C devices that will be skipped
1979 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1980 is set, specify a list of bus-device pairs. Otherwise, specify
1981 a 1D array of device addresses
1984 #undef CONFIG_I2C_MULTI_BUS
1985 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1987 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1989 #define CONFIG_I2C_MULTI_BUS
1990 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1992 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1994 CONFIG_SYS_SPD_BUS_NUM
1996 If defined, then this indicates the I2C bus number for DDR SPD.
1997 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1999 CONFIG_SYS_RTC_BUS_NUM
2001 If defined, then this indicates the I2C bus number for the RTC.
2002 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2004 CONFIG_SYS_DTT_BUS_NUM
2006 If defined, then this indicates the I2C bus number for the DTT.
2007 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2009 CONFIG_SYS_I2C_DTT_ADDR:
2011 If defined, specifies the I2C address of the DTT device.
2012 If not defined, then U-Boot uses predefined value for
2013 specified DTT device.
2017 Define this option if you want to use Freescale's I2C driver in
2018 drivers/i2c/fsl_i2c.c.
2022 Define this option if you have I2C devices reached over 1 .. n
2023 I2C Muxes like the pca9544a. This option addes a new I2C
2024 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2025 new I2C Bus to the existing I2C Busses. If you select the
2026 new Bus with "i2c dev", u-bbot sends first the commandos for
2027 the muxes to activate this new "bus".
2029 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2033 Adding a new I2C Bus reached over 2 pca9544a muxes
2034 The First mux with address 70 and channel 6
2035 The Second mux with address 71 and channel 4
2037 => i2c bus pca9544a:70:6:pca9544a:71:4
2039 Use the "i2c bus" command without parameter, to get a list
2040 of I2C Busses with muxes:
2043 Busses reached over muxes:
2045 reached over Mux(es):
2048 reached over Mux(es):
2053 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2054 u-boot first sends the command to the mux@70 to enable
2055 channel 6, and then the command to the mux@71 to enable
2058 After that, you can use the "normal" i2c commands as
2059 usual to communicate with your I2C devices behind
2062 This option is actually implemented for the bitbanging
2063 algorithm in common/soft_i2c.c and for the Hardware I2C
2064 Bus on the MPC8260. But it should be not so difficult
2065 to add this option to other architectures.
2067 CONFIG_SOFT_I2C_READ_REPEATED_START
2069 defining this will force the i2c_read() function in
2070 the soft_i2c driver to perform an I2C repeated start
2071 between writing the address pointer and reading the
2072 data. If this define is omitted the default behaviour
2073 of doing a stop-start sequence will be used. Most I2C
2074 devices can use either method, but some require one or
2077 - SPI Support: CONFIG_SPI
2079 Enables SPI driver (so far only tested with
2080 SPI EEPROM, also an instance works with Crystal A/D and
2081 D/As on the SACSng board)
2085 Enables the driver for SPI controller on SuperH. Currently
2086 only SH7757 is supported.
2090 Enables extended (16-bit) SPI EEPROM addressing.
2091 (symmetrical to CONFIG_I2C_X)
2095 Enables a software (bit-bang) SPI driver rather than
2096 using hardware support. This is a general purpose
2097 driver that only requires three general I/O port pins
2098 (two outputs, one input) to function. If this is
2099 defined, the board configuration must define several
2100 SPI configuration items (port pins to use, etc). For
2101 an example, see include/configs/sacsng.h.
2105 Enables a hardware SPI driver for general-purpose reads
2106 and writes. As with CONFIG_SOFT_SPI, the board configuration
2107 must define a list of chip-select function pointers.
2108 Currently supported on some MPC8xxx processors. For an
2109 example, see include/configs/mpc8349emds.h.
2113 Enables the driver for the SPI controllers on i.MX and MXC
2114 SoCs. Currently i.MX31/35/51 are supported.
2116 - FPGA Support: CONFIG_FPGA
2118 Enables FPGA subsystem.
2120 CONFIG_FPGA_<vendor>
2122 Enables support for specific chip vendors.
2125 CONFIG_FPGA_<family>
2127 Enables support for FPGA family.
2128 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2132 Specify the number of FPGA devices to support.
2134 CONFIG_SYS_FPGA_PROG_FEEDBACK
2136 Enable printing of hash marks during FPGA configuration.
2138 CONFIG_SYS_FPGA_CHECK_BUSY
2140 Enable checks on FPGA configuration interface busy
2141 status by the configuration function. This option
2142 will require a board or device specific function to
2147 If defined, a function that provides delays in the FPGA
2148 configuration driver.
2150 CONFIG_SYS_FPGA_CHECK_CTRLC
2151 Allow Control-C to interrupt FPGA configuration
2153 CONFIG_SYS_FPGA_CHECK_ERROR
2155 Check for configuration errors during FPGA bitfile
2156 loading. For example, abort during Virtex II
2157 configuration if the INIT_B line goes low (which
2158 indicated a CRC error).
2160 CONFIG_SYS_FPGA_WAIT_INIT
2162 Maximum time to wait for the INIT_B line to deassert
2163 after PROB_B has been deasserted during a Virtex II
2164 FPGA configuration sequence. The default time is 500
2167 CONFIG_SYS_FPGA_WAIT_BUSY
2169 Maximum time to wait for BUSY to deassert during
2170 Virtex II FPGA configuration. The default is 5 ms.
2172 CONFIG_SYS_FPGA_WAIT_CONFIG
2174 Time to wait after FPGA configuration. The default is
2177 - Configuration Management:
2180 If defined, this string will be added to the U-Boot
2181 version information (U_BOOT_VERSION)
2183 - Vendor Parameter Protection:
2185 U-Boot considers the values of the environment
2186 variables "serial#" (Board Serial Number) and
2187 "ethaddr" (Ethernet Address) to be parameters that
2188 are set once by the board vendor / manufacturer, and
2189 protects these variables from casual modification by
2190 the user. Once set, these variables are read-only,
2191 and write or delete attempts are rejected. You can
2192 change this behaviour:
2194 If CONFIG_ENV_OVERWRITE is #defined in your config
2195 file, the write protection for vendor parameters is
2196 completely disabled. Anybody can change or delete
2199 Alternatively, if you #define _both_ CONFIG_ETHADDR
2200 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2201 Ethernet address is installed in the environment,
2202 which can be changed exactly ONCE by the user. [The
2203 serial# is unaffected by this, i. e. it remains
2206 The same can be accomplished in a more flexible way
2207 for any variable by configuring the type of access
2208 to allow for those variables in the ".flags" variable
2209 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2214 Define this variable to enable the reservation of
2215 "protected RAM", i. e. RAM which is not overwritten
2216 by U-Boot. Define CONFIG_PRAM to hold the number of
2217 kB you want to reserve for pRAM. You can overwrite
2218 this default value by defining an environment
2219 variable "pram" to the number of kB you want to
2220 reserve. Note that the board info structure will
2221 still show the full amount of RAM. If pRAM is
2222 reserved, a new environment variable "mem" will
2223 automatically be defined to hold the amount of
2224 remaining RAM in a form that can be passed as boot
2225 argument to Linux, for instance like that:
2227 setenv bootargs ... mem=\${mem}
2230 This way you can tell Linux not to use this memory,
2231 either, which results in a memory region that will
2232 not be affected by reboots.
2234 *WARNING* If your board configuration uses automatic
2235 detection of the RAM size, you must make sure that
2236 this memory test is non-destructive. So far, the
2237 following board configurations are known to be
2240 IVMS8, IVML24, SPD8xx, TQM8xxL,
2241 HERMES, IP860, RPXlite, LWMON,
2244 - Access to physical memory region (> 4GB)
2245 Some basic support is provided for operations on memory not
2246 normally accessible to U-Boot - e.g. some architectures
2247 support access to more than 4GB of memory on 32-bit
2248 machines using physical address extension or similar.
2249 Define CONFIG_PHYSMEM to access this basic support, which
2250 currently only supports clearing the memory.
2255 Define this variable to stop the system in case of a
2256 fatal error, so that you have to reset it manually.
2257 This is probably NOT a good idea for an embedded
2258 system where you want the system to reboot
2259 automatically as fast as possible, but it may be
2260 useful during development since you can try to debug
2261 the conditions that lead to the situation.
2263 CONFIG_NET_RETRY_COUNT
2265 This variable defines the number of retries for
2266 network operations like ARP, RARP, TFTP, or BOOTP
2267 before giving up the operation. If not defined, a
2268 default value of 5 is used.
2272 Timeout waiting for an ARP reply in milliseconds.
2276 Timeout in milliseconds used in NFS protocol.
2277 If you encounter "ERROR: Cannot umount" in nfs command,
2278 try longer timeout such as
2279 #define CONFIG_NFS_TIMEOUT 10000UL
2281 - Command Interpreter:
2282 CONFIG_AUTO_COMPLETE
2284 Enable auto completion of commands using TAB.
2286 Note that this feature has NOT been implemented yet
2287 for the "hush" shell.
2290 CONFIG_SYS_HUSH_PARSER
2292 Define this variable to enable the "hush" shell (from
2293 Busybox) as command line interpreter, thus enabling
2294 powerful command line syntax like
2295 if...then...else...fi conditionals or `&&' and '||'
2296 constructs ("shell scripts").
2298 If undefined, you get the old, much simpler behaviour
2299 with a somewhat smaller memory footprint.
2302 CONFIG_SYS_PROMPT_HUSH_PS2
2304 This defines the secondary prompt string, which is
2305 printed when the command interpreter needs more input
2306 to complete a command. Usually "> ".
2310 In the current implementation, the local variables
2311 space and global environment variables space are
2312 separated. Local variables are those you define by
2313 simply typing `name=value'. To access a local
2314 variable later on, you have write `$name' or
2315 `${name}'; to execute the contents of a variable
2316 directly type `$name' at the command prompt.
2318 Global environment variables are those you use
2319 setenv/printenv to work with. To run a command stored
2320 in such a variable, you need to use the run command,
2321 and you must not use the '$' sign to access them.
2323 To store commands and special characters in a
2324 variable, please use double quotation marks
2325 surrounding the whole text of the variable, instead
2326 of the backslashes before semicolons and special
2329 - Commandline Editing and History:
2330 CONFIG_CMDLINE_EDITING
2332 Enable editing and History functions for interactive
2333 commandline input operations
2335 - Default Environment:
2336 CONFIG_EXTRA_ENV_SETTINGS
2338 Define this to contain any number of null terminated
2339 strings (variable = value pairs) that will be part of
2340 the default environment compiled into the boot image.
2342 For example, place something like this in your
2343 board's config file:
2345 #define CONFIG_EXTRA_ENV_SETTINGS \
2349 Warning: This method is based on knowledge about the
2350 internal format how the environment is stored by the
2351 U-Boot code. This is NOT an official, exported
2352 interface! Although it is unlikely that this format
2353 will change soon, there is no guarantee either.
2354 You better know what you are doing here.
2356 Note: overly (ab)use of the default environment is
2357 discouraged. Make sure to check other ways to preset
2358 the environment like the "source" command or the
2361 CONFIG_ENV_VARS_UBOOT_CONFIG
2363 Define this in order to add variables describing the
2364 U-Boot build configuration to the default environment.
2365 These will be named arch, cpu, board, vendor, and soc.
2367 Enabling this option will cause the following to be defined:
2375 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2377 Define this in order to add variables describing certain
2378 run-time determined information about the hardware to the
2379 environment. These will be named board_name, board_rev.
2381 CONFIG_DELAY_ENVIRONMENT
2383 Normally the environment is loaded when the board is
2384 intialised so that it is available to U-Boot. This inhibits
2385 that so that the environment is not available until
2386 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2387 this is instead controlled by the value of
2388 /config/load-environment.
2390 - DataFlash Support:
2391 CONFIG_HAS_DATAFLASH
2393 Defining this option enables DataFlash features and
2394 allows to read/write in Dataflash via the standard
2397 - Serial Flash support
2400 Defining this option enables SPI flash commands
2401 'sf probe/read/write/erase/update'.
2403 Usage requires an initial 'probe' to define the serial
2404 flash parameters, followed by read/write/erase/update
2407 The following defaults may be provided by the platform
2408 to handle the common case when only a single serial
2409 flash is present on the system.
2411 CONFIG_SF_DEFAULT_BUS Bus identifier
2412 CONFIG_SF_DEFAULT_CS Chip-select
2413 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2414 CONFIG_SF_DEFAULT_SPEED in Hz
2416 - SystemACE Support:
2419 Adding this option adds support for Xilinx SystemACE
2420 chips attached via some sort of local bus. The address
2421 of the chip must also be defined in the
2422 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2424 #define CONFIG_SYSTEMACE
2425 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2427 When SystemACE support is added, the "ace" device type
2428 becomes available to the fat commands, i.e. fatls.
2430 - TFTP Fixed UDP Port:
2433 If this is defined, the environment variable tftpsrcp
2434 is used to supply the TFTP UDP source port value.
2435 If tftpsrcp isn't defined, the normal pseudo-random port
2436 number generator is used.
2438 Also, the environment variable tftpdstp is used to supply
2439 the TFTP UDP destination port value. If tftpdstp isn't
2440 defined, the normal port 69 is used.
2442 The purpose for tftpsrcp is to allow a TFTP server to
2443 blindly start the TFTP transfer using the pre-configured
2444 target IP address and UDP port. This has the effect of
2445 "punching through" the (Windows XP) firewall, allowing
2446 the remainder of the TFTP transfer to proceed normally.
2447 A better solution is to properly configure the firewall,
2448 but sometimes that is not allowed.
2453 This enables a generic 'hash' command which can produce
2454 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2458 Enable the hash verify command (hash -v). This adds to code
2461 CONFIG_SHA1 - support SHA1 hashing
2462 CONFIG_SHA256 - support SHA256 hashing
2464 Note: There is also a sha1sum command, which should perhaps
2465 be deprecated in favour of 'hash sha1'.
2467 - Show boot progress:
2468 CONFIG_SHOW_BOOT_PROGRESS
2470 Defining this option allows to add some board-
2471 specific code (calling a user-provided function
2472 "show_boot_progress(int)") that enables you to show
2473 the system's boot progress on some display (for
2474 example, some LED's) on your board. At the moment,
2475 the following checkpoints are implemented:
2477 - Detailed boot stage timing
2479 Define this option to get detailed timing of each stage
2480 of the boot process.
2482 CONFIG_BOOTSTAGE_USER_COUNT
2483 This is the number of available user bootstage records.
2484 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2485 a new ID will be allocated from this stash. If you exceed
2486 the limit, recording will stop.
2488 CONFIG_BOOTSTAGE_REPORT
2489 Define this to print a report before boot, similar to this:
2491 Timer summary in microseconds:
2494 3,575,678 3,575,678 board_init_f start
2495 3,575,695 17 arch_cpu_init A9
2496 3,575,777 82 arch_cpu_init done
2497 3,659,598 83,821 board_init_r start
2498 3,910,375 250,777 main_loop
2499 29,916,167 26,005,792 bootm_start
2500 30,361,327 445,160 start_kernel
2502 CONFIG_CMD_BOOTSTAGE
2503 Add a 'bootstage' command which supports printing a report
2504 and un/stashing of bootstage data.
2506 CONFIG_BOOTSTAGE_FDT
2507 Stash the bootstage information in the FDT. A root 'bootstage'
2508 node is created with each bootstage id as a child. Each child
2509 has a 'name' property and either 'mark' containing the
2510 mark time in microsecond, or 'accum' containing the
2511 accumulated time for that bootstage id in microseconds.
2516 name = "board_init_f";
2525 Code in the Linux kernel can find this in /proc/devicetree.
2527 Legacy uImage format:
2530 1 common/cmd_bootm.c before attempting to boot an image
2531 -1 common/cmd_bootm.c Image header has bad magic number
2532 2 common/cmd_bootm.c Image header has correct magic number
2533 -2 common/cmd_bootm.c Image header has bad checksum
2534 3 common/cmd_bootm.c Image header has correct checksum
2535 -3 common/cmd_bootm.c Image data has bad checksum
2536 4 common/cmd_bootm.c Image data has correct checksum
2537 -4 common/cmd_bootm.c Image is for unsupported architecture
2538 5 common/cmd_bootm.c Architecture check OK
2539 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2540 6 common/cmd_bootm.c Image Type check OK
2541 -6 common/cmd_bootm.c gunzip uncompression error
2542 -7 common/cmd_bootm.c Unimplemented compression type
2543 7 common/cmd_bootm.c Uncompression OK
2544 8 common/cmd_bootm.c No uncompress/copy overwrite error
2545 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2547 9 common/image.c Start initial ramdisk verification
2548 -10 common/image.c Ramdisk header has bad magic number
2549 -11 common/image.c Ramdisk header has bad checksum
2550 10 common/image.c Ramdisk header is OK
2551 -12 common/image.c Ramdisk data has bad checksum
2552 11 common/image.c Ramdisk data has correct checksum
2553 12 common/image.c Ramdisk verification complete, start loading
2554 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2555 13 common/image.c Start multifile image verification
2556 14 common/image.c No initial ramdisk, no multifile, continue.
2558 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2560 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2561 -31 post/post.c POST test failed, detected by post_output_backlog()
2562 -32 post/post.c POST test failed, detected by post_run_single()
2564 34 common/cmd_doc.c before loading a Image from a DOC device
2565 -35 common/cmd_doc.c Bad usage of "doc" command
2566 35 common/cmd_doc.c correct usage of "doc" command
2567 -36 common/cmd_doc.c No boot device
2568 36 common/cmd_doc.c correct boot device
2569 -37 common/cmd_doc.c Unknown Chip ID on boot device
2570 37 common/cmd_doc.c correct chip ID found, device available
2571 -38 common/cmd_doc.c Read Error on boot device
2572 38 common/cmd_doc.c reading Image header from DOC device OK
2573 -39 common/cmd_doc.c Image header has bad magic number
2574 39 common/cmd_doc.c Image header has correct magic number
2575 -40 common/cmd_doc.c Error reading Image from DOC device
2576 40 common/cmd_doc.c Image header has correct magic number
2577 41 common/cmd_ide.c before loading a Image from a IDE device
2578 -42 common/cmd_ide.c Bad usage of "ide" command
2579 42 common/cmd_ide.c correct usage of "ide" command
2580 -43 common/cmd_ide.c No boot device
2581 43 common/cmd_ide.c boot device found
2582 -44 common/cmd_ide.c Device not available
2583 44 common/cmd_ide.c Device available
2584 -45 common/cmd_ide.c wrong partition selected
2585 45 common/cmd_ide.c partition selected
2586 -46 common/cmd_ide.c Unknown partition table
2587 46 common/cmd_ide.c valid partition table found
2588 -47 common/cmd_ide.c Invalid partition type
2589 47 common/cmd_ide.c correct partition type
2590 -48 common/cmd_ide.c Error reading Image Header on boot device
2591 48 common/cmd_ide.c reading Image Header from IDE device OK
2592 -49 common/cmd_ide.c Image header has bad magic number
2593 49 common/cmd_ide.c Image header has correct magic number
2594 -50 common/cmd_ide.c Image header has bad checksum
2595 50 common/cmd_ide.c Image header has correct checksum
2596 -51 common/cmd_ide.c Error reading Image from IDE device
2597 51 common/cmd_ide.c reading Image from IDE device OK
2598 52 common/cmd_nand.c before loading a Image from a NAND device
2599 -53 common/cmd_nand.c Bad usage of "nand" command
2600 53 common/cmd_nand.c correct usage of "nand" command
2601 -54 common/cmd_nand.c No boot device
2602 54 common/cmd_nand.c boot device found
2603 -55 common/cmd_nand.c Unknown Chip ID on boot device
2604 55 common/cmd_nand.c correct chip ID found, device available
2605 -56 common/cmd_nand.c Error reading Image Header on boot device
2606 56 common/cmd_nand.c reading Image Header from NAND device OK
2607 -57 common/cmd_nand.c Image header has bad magic number
2608 57 common/cmd_nand.c Image header has correct magic number
2609 -58 common/cmd_nand.c Error reading Image from NAND device
2610 58 common/cmd_nand.c reading Image from NAND device OK
2612 -60 common/env_common.c Environment has a bad CRC, using default
2614 64 net/eth.c starting with Ethernet configuration.
2615 -64 net/eth.c no Ethernet found.
2616 65 net/eth.c Ethernet found.
2618 -80 common/cmd_net.c usage wrong
2619 80 common/cmd_net.c before calling NetLoop()
2620 -81 common/cmd_net.c some error in NetLoop() occurred
2621 81 common/cmd_net.c NetLoop() back without error
2622 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2623 82 common/cmd_net.c trying automatic boot
2624 83 common/cmd_net.c running "source" command
2625 -83 common/cmd_net.c some error in automatic boot or "source" command
2626 84 common/cmd_net.c end without errors
2631 100 common/cmd_bootm.c Kernel FIT Image has correct format
2632 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2633 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2634 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2635 102 common/cmd_bootm.c Kernel unit name specified
2636 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2637 103 common/cmd_bootm.c Found configuration node
2638 104 common/cmd_bootm.c Got kernel subimage node offset
2639 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2640 105 common/cmd_bootm.c Kernel subimage hash verification OK
2641 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2642 106 common/cmd_bootm.c Architecture check OK
2643 -106 common/cmd_bootm.c Kernel subimage has wrong type
2644 107 common/cmd_bootm.c Kernel subimage type OK
2645 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2646 108 common/cmd_bootm.c Got kernel subimage data/size
2647 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2648 -109 common/cmd_bootm.c Can't get kernel subimage type
2649 -110 common/cmd_bootm.c Can't get kernel subimage comp
2650 -111 common/cmd_bootm.c Can't get kernel subimage os
2651 -112 common/cmd_bootm.c Can't get kernel subimage load address
2652 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2654 120 common/image.c Start initial ramdisk verification
2655 -120 common/image.c Ramdisk FIT image has incorrect format
2656 121 common/image.c Ramdisk FIT image has correct format
2657 122 common/image.c No ramdisk subimage unit name, using configuration
2658 -122 common/image.c Can't get configuration for ramdisk subimage
2659 123 common/image.c Ramdisk unit name specified
2660 -124 common/image.c Can't get ramdisk subimage node offset
2661 125 common/image.c Got ramdisk subimage node offset
2662 -125 common/image.c Ramdisk subimage hash verification failed
2663 126 common/image.c Ramdisk subimage hash verification OK
2664 -126 common/image.c Ramdisk subimage for unsupported architecture
2665 127 common/image.c Architecture check OK
2666 -127 common/image.c Can't get ramdisk subimage data/size
2667 128 common/image.c Got ramdisk subimage data/size
2668 129 common/image.c Can't get ramdisk load address
2669 -129 common/image.c Got ramdisk load address
2671 -130 common/cmd_doc.c Incorrect FIT image format
2672 131 common/cmd_doc.c FIT image format OK
2674 -140 common/cmd_ide.c Incorrect FIT image format
2675 141 common/cmd_ide.c FIT image format OK
2677 -150 common/cmd_nand.c Incorrect FIT image format
2678 151 common/cmd_nand.c FIT image format OK
2680 - FIT image support:
2682 Enable support for the FIT uImage format.
2684 CONFIG_FIT_BEST_MATCH
2685 When no configuration is explicitly selected, default to the
2686 one whose fdt's compatibility field best matches that of
2687 U-Boot itself. A match is considered "best" if it matches the
2688 most specific compatibility entry of U-Boot's fdt's root node.
2689 The order of entries in the configuration's fdt is ignored.
2691 - Standalone program support:
2692 CONFIG_STANDALONE_LOAD_ADDR
2694 This option defines a board specific value for the
2695 address where standalone program gets loaded, thus
2696 overwriting the architecture dependent default
2699 - Frame Buffer Address:
2702 Define CONFIG_FB_ADDR if you want to use specific
2703 address for frame buffer.
2704 Then system will reserve the frame buffer address to
2705 defined address instead of lcd_setmem (this function
2706 grabs the memory for frame buffer by panel's size).
2708 Please see board_init_f function.
2710 - Automatic software updates via TFTP server
2712 CONFIG_UPDATE_TFTP_CNT_MAX
2713 CONFIG_UPDATE_TFTP_MSEC_MAX
2715 These options enable and control the auto-update feature;
2716 for a more detailed description refer to doc/README.update.
2718 - MTD Support (mtdparts command, UBI support)
2721 Adds the MTD device infrastructure from the Linux kernel.
2722 Needed for mtdparts command support.
2724 CONFIG_MTD_PARTITIONS
2726 Adds the MTD partitioning infrastructure from the Linux
2727 kernel. Needed for UBI support.
2731 Enable building of SPL globally.
2734 LDSCRIPT for linking the SPL binary.
2737 Maximum binary size (text, data and rodata) of the SPL binary.
2739 CONFIG_SPL_TEXT_BASE
2740 TEXT_BASE for linking the SPL binary.
2742 CONFIG_SPL_RELOC_TEXT_BASE
2743 Address to relocate to. If unspecified, this is equal to
2744 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2746 CONFIG_SPL_BSS_START_ADDR
2747 Link address for the BSS within the SPL binary.
2749 CONFIG_SPL_BSS_MAX_SIZE
2750 Maximum binary size of the BSS section of the SPL binary.
2753 Adress of the start of the stack SPL will use
2755 CONFIG_SPL_RELOC_STACK
2756 Adress of the start of the stack SPL will use after
2757 relocation. If unspecified, this is equal to
2760 CONFIG_SYS_SPL_MALLOC_START
2761 Starting address of the malloc pool used in SPL.
2763 CONFIG_SYS_SPL_MALLOC_SIZE
2764 The size of the malloc pool used in SPL.
2766 CONFIG_SPL_FRAMEWORK
2767 Enable the SPL framework under common/. This framework
2768 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2769 NAND loading of the Linux Kernel.
2771 CONFIG_SPL_DISPLAY_PRINT
2772 For ARM, enable an optional function to print more information
2773 about the running system.
2775 CONFIG_SPL_INIT_MINIMAL
2776 Arch init code should be built for a very small image
2778 CONFIG_SPL_LIBCOMMON_SUPPORT
2779 Support for common/libcommon.o in SPL binary
2781 CONFIG_SPL_LIBDISK_SUPPORT
2782 Support for disk/libdisk.o in SPL binary
2784 CONFIG_SPL_I2C_SUPPORT
2785 Support for drivers/i2c/libi2c.o in SPL binary
2787 CONFIG_SPL_GPIO_SUPPORT
2788 Support for drivers/gpio/libgpio.o in SPL binary
2790 CONFIG_SPL_MMC_SUPPORT
2791 Support for drivers/mmc/libmmc.o in SPL binary
2793 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2794 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2795 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2796 Address, size and partition on the MMC to load U-Boot from
2797 when the MMC is being used in raw mode.
2799 CONFIG_SPL_FAT_SUPPORT
2800 Support for fs/fat/libfat.o in SPL binary
2802 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2803 Filename to read to load U-Boot when reading from FAT
2805 CONFIG_SPL_NAND_BASE
2806 Include nand_base.c in the SPL. Requires
2807 CONFIG_SPL_NAND_DRIVERS.
2809 CONFIG_SPL_NAND_DRIVERS
2810 SPL uses normal NAND drivers, not minimal drivers.
2813 Include standard software ECC in the SPL
2815 CONFIG_SPL_NAND_SIMPLE
2816 Support for NAND boot using simple NAND drivers that
2817 expose the cmd_ctrl() interface.
2819 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2820 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2821 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2822 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2823 CONFIG_SYS_NAND_ECCBYTES
2824 Defines the size and behavior of the NAND that SPL uses
2827 CONFIG_SYS_NAND_U_BOOT_OFFS
2828 Location in NAND to read U-Boot from
2830 CONFIG_SYS_NAND_U_BOOT_DST
2831 Location in memory to load U-Boot to
2833 CONFIG_SYS_NAND_U_BOOT_SIZE
2834 Size of image to load
2836 CONFIG_SYS_NAND_U_BOOT_START
2837 Entry point in loaded image to jump to
2839 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2840 Define this if you need to first read the OOB and then the
2841 data. This is used for example on davinci plattforms.
2843 CONFIG_SPL_OMAP3_ID_NAND
2844 Support for an OMAP3-specific set of functions to return the
2845 ID and MFR of the first attached NAND chip, if present.
2847 CONFIG_SPL_SERIAL_SUPPORT
2848 Support for drivers/serial/libserial.o in SPL binary
2850 CONFIG_SPL_SPI_FLASH_SUPPORT
2851 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2853 CONFIG_SPL_SPI_SUPPORT
2854 Support for drivers/spi/libspi.o in SPL binary
2856 CONFIG_SPL_RAM_DEVICE
2857 Support for running image already present in ram, in SPL binary
2859 CONFIG_SPL_LIBGENERIC_SUPPORT
2860 Support for lib/libgeneric.o in SPL binary
2863 Final target image containing SPL and payload. Some SPLs
2864 use an arch-specific makefile fragment instead, for
2865 example if more than one image needs to be produced.
2870 [so far only for SMDK2400 boards]
2872 - Modem support enable:
2873 CONFIG_MODEM_SUPPORT
2875 - RTS/CTS Flow control enable:
2878 - Modem debug support:
2879 CONFIG_MODEM_SUPPORT_DEBUG
2881 Enables debugging stuff (char screen[1024], dbg())
2882 for modem support. Useful only with BDI2000.
2884 - Interrupt support (PPC):
2886 There are common interrupt_init() and timer_interrupt()
2887 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2888 for CPU specific initialization. interrupt_init_cpu()
2889 should set decrementer_count to appropriate value. If
2890 CPU resets decrementer automatically after interrupt
2891 (ppc4xx) it should set decrementer_count to zero.
2892 timer_interrupt() calls timer_interrupt_cpu() for CPU
2893 specific handling. If board has watchdog / status_led
2894 / other_activity_monitor it works automatically from
2895 general timer_interrupt().
2899 In the target system modem support is enabled when a
2900 specific key (key combination) is pressed during
2901 power-on. Otherwise U-Boot will boot normally
2902 (autoboot). The key_pressed() function is called from
2903 board_init(). Currently key_pressed() is a dummy
2904 function, returning 1 and thus enabling modem
2907 If there are no modem init strings in the
2908 environment, U-Boot proceed to autoboot; the
2909 previous output (banner, info printfs) will be
2912 See also: doc/README.Modem
2914 Board initialization settings:
2915 ------------------------------
2917 During Initialization u-boot calls a number of board specific functions
2918 to allow the preparation of board specific prerequisites, e.g. pin setup
2919 before drivers are initialized. To enable these callbacks the
2920 following configuration macros have to be defined. Currently this is
2921 architecture specific, so please check arch/your_architecture/lib/board.c
2922 typically in board_init_f() and board_init_r().
2924 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2925 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2926 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2927 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2929 Configuration Settings:
2930 -----------------------
2932 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2933 undefine this when you're short of memory.
2935 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2936 width of the commands listed in the 'help' command output.
2938 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2939 prompt for user input.
2941 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2943 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2945 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2947 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2948 the application (usually a Linux kernel) when it is
2951 - CONFIG_SYS_BAUDRATE_TABLE:
2952 List of legal baudrate settings for this board.
2954 - CONFIG_SYS_CONSOLE_INFO_QUIET
2955 Suppress display of console information at boot.
2957 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2958 If the board specific function
2959 extern int overwrite_console (void);
2960 returns 1, the stdin, stderr and stdout are switched to the
2961 serial port, else the settings in the environment are used.
2963 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2964 Enable the call to overwrite_console().
2966 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2967 Enable overwrite of previous console environment settings.
2969 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2970 Begin and End addresses of the area used by the
2973 - CONFIG_SYS_ALT_MEMTEST:
2974 Enable an alternate, more extensive memory test.
2976 - CONFIG_SYS_MEMTEST_SCRATCH:
2977 Scratch address used by the alternate memory test
2978 You only need to set this if address zero isn't writeable
2980 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2981 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2982 this specified memory area will get subtracted from the top
2983 (end) of RAM and won't get "touched" at all by U-Boot. By
2984 fixing up gd->ram_size the Linux kernel should gets passed
2985 the now "corrected" memory size and won't touch it either.
2986 This should work for arch/ppc and arch/powerpc. Only Linux
2987 board ports in arch/powerpc with bootwrapper support that
2988 recalculate the memory size from the SDRAM controller setup
2989 will have to get fixed in Linux additionally.
2991 This option can be used as a workaround for the 440EPx/GRx
2992 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2995 WARNING: Please make sure that this value is a multiple of
2996 the Linux page size (normally 4k). If this is not the case,
2997 then the end address of the Linux memory will be located at a
2998 non page size aligned address and this could cause major
3001 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3002 Enable temporary baudrate change while serial download
3004 - CONFIG_SYS_SDRAM_BASE:
3005 Physical start address of SDRAM. _Must_ be 0 here.
3007 - CONFIG_SYS_MBIO_BASE:
3008 Physical start address of Motherboard I/O (if using a
3011 - CONFIG_SYS_FLASH_BASE:
3012 Physical start address of Flash memory.
3014 - CONFIG_SYS_MONITOR_BASE:
3015 Physical start address of boot monitor code (set by
3016 make config files to be same as the text base address
3017 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3018 CONFIG_SYS_FLASH_BASE when booting from flash.
3020 - CONFIG_SYS_MONITOR_LEN:
3021 Size of memory reserved for monitor code, used to
3022 determine _at_compile_time_ (!) if the environment is
3023 embedded within the U-Boot image, or in a separate
3026 - CONFIG_SYS_MALLOC_LEN:
3027 Size of DRAM reserved for malloc() use.
3029 - CONFIG_SYS_BOOTM_LEN:
3030 Normally compressed uImages are limited to an
3031 uncompressed size of 8 MBytes. If this is not enough,
3032 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3033 to adjust this setting to your needs.
3035 - CONFIG_SYS_BOOTMAPSZ:
3036 Maximum size of memory mapped by the startup code of
3037 the Linux kernel; all data that must be processed by
3038 the Linux kernel (bd_info, boot arguments, FDT blob if
3039 used) must be put below this limit, unless "bootm_low"
3040 enviroment variable is defined and non-zero. In such case
3041 all data for the Linux kernel must be between "bootm_low"
3042 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3043 variable "bootm_mapsize" will override the value of
3044 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3045 then the value in "bootm_size" will be used instead.
3047 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3048 Enable initrd_high functionality. If defined then the
3049 initrd_high feature is enabled and the bootm ramdisk subcommand
3052 - CONFIG_SYS_BOOT_GET_CMDLINE:
3053 Enables allocating and saving kernel cmdline in space between
3054 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3056 - CONFIG_SYS_BOOT_GET_KBD:
3057 Enables allocating and saving a kernel copy of the bd_info in
3058 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3060 - CONFIG_SYS_MAX_FLASH_BANKS:
3061 Max number of Flash memory banks
3063 - CONFIG_SYS_MAX_FLASH_SECT:
3064 Max number of sectors on a Flash chip
3066 - CONFIG_SYS_FLASH_ERASE_TOUT:
3067 Timeout for Flash erase operations (in ms)
3069 - CONFIG_SYS_FLASH_WRITE_TOUT:
3070 Timeout for Flash write operations (in ms)
3072 - CONFIG_SYS_FLASH_LOCK_TOUT
3073 Timeout for Flash set sector lock bit operation (in ms)
3075 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3076 Timeout for Flash clear lock bits operation (in ms)
3078 - CONFIG_SYS_FLASH_PROTECTION
3079 If defined, hardware flash sectors protection is used
3080 instead of U-Boot software protection.
3082 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3084 Enable TFTP transfers directly to flash memory;
3085 without this option such a download has to be
3086 performed in two steps: (1) download to RAM, and (2)
3087 copy from RAM to flash.
3089 The two-step approach is usually more reliable, since
3090 you can check if the download worked before you erase
3091 the flash, but in some situations (when system RAM is
3092 too limited to allow for a temporary copy of the
3093 downloaded image) this option may be very useful.
3095 - CONFIG_SYS_FLASH_CFI:
3096 Define if the flash driver uses extra elements in the
3097 common flash structure for storing flash geometry.
3099 - CONFIG_FLASH_CFI_DRIVER
3100 This option also enables the building of the cfi_flash driver
3101 in the drivers directory
3103 - CONFIG_FLASH_CFI_MTD
3104 This option enables the building of the cfi_mtd driver
3105 in the drivers directory. The driver exports CFI flash
3108 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3109 Use buffered writes to flash.
3111 - CONFIG_FLASH_SPANSION_S29WS_N
3112 s29ws-n MirrorBit flash has non-standard addresses for buffered
3115 - CONFIG_SYS_FLASH_QUIET_TEST
3116 If this option is defined, the common CFI flash doesn't
3117 print it's warning upon not recognized FLASH banks. This
3118 is useful, if some of the configured banks are only
3119 optionally available.
3121 - CONFIG_FLASH_SHOW_PROGRESS
3122 If defined (must be an integer), print out countdown
3123 digits and dots. Recommended value: 45 (9..1) for 80
3124 column displays, 15 (3..1) for 40 column displays.
3126 - CONFIG_SYS_RX_ETH_BUFFER:
3127 Defines the number of Ethernet receive buffers. On some
3128 Ethernet controllers it is recommended to set this value
3129 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3130 buffers can be full shortly after enabling the interface
3131 on high Ethernet traffic.
3132 Defaults to 4 if not defined.
3134 - CONFIG_ENV_MAX_ENTRIES
3136 Maximum number of entries in the hash table that is used
3137 internally to store the environment settings. The default
3138 setting is supposed to be generous and should work in most
3139 cases. This setting can be used to tune behaviour; see
3140 lib/hashtable.c for details.
3142 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3143 - CONFIG_ENV_FLAGS_LIST_STATIC
3144 Enable validation of the values given to enviroment variables when
3145 calling env set. Variables can be restricted to only decimal,
3146 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3147 the variables can also be restricted to IP address or MAC address.
3149 The format of the list is:
3150 type_attribute = [s|d|x|b|i|m]
3151 access_atribute = [a|r|o|c]
3152 attributes = type_attribute[access_atribute]
3153 entry = variable_name[:attributes]
3156 The type attributes are:
3157 s - String (default)
3160 b - Boolean ([1yYtT|0nNfF])
3164 The access attributes are:
3170 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3171 Define this to a list (string) to define the ".flags"
3172 envirnoment variable in the default or embedded environment.
3174 - CONFIG_ENV_FLAGS_LIST_STATIC
3175 Define this to a list (string) to define validation that
3176 should be done if an entry is not found in the ".flags"
3177 environment variable. To override a setting in the static
3178 list, simply add an entry for the same variable name to the
3181 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3182 If defined, don't allow the -f switch to env set override variable
3185 The following definitions that deal with the placement and management
3186 of environment data (variable area); in general, we support the
3187 following configurations:
3189 - CONFIG_BUILD_ENVCRC:
3191 Builds up envcrc with the target environment so that external utils
3192 may easily extract it and embed it in final U-Boot images.
3194 - CONFIG_ENV_IS_IN_FLASH:
3196 Define this if the environment is in flash memory.
3198 a) The environment occupies one whole flash sector, which is
3199 "embedded" in the text segment with the U-Boot code. This
3200 happens usually with "bottom boot sector" or "top boot
3201 sector" type flash chips, which have several smaller
3202 sectors at the start or the end. For instance, such a
3203 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3204 such a case you would place the environment in one of the
3205 4 kB sectors - with U-Boot code before and after it. With
3206 "top boot sector" type flash chips, you would put the
3207 environment in one of the last sectors, leaving a gap
3208 between U-Boot and the environment.
3210 - CONFIG_ENV_OFFSET:
3212 Offset of environment data (variable area) to the
3213 beginning of flash memory; for instance, with bottom boot
3214 type flash chips the second sector can be used: the offset
3215 for this sector is given here.
3217 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3221 This is just another way to specify the start address of
3222 the flash sector containing the environment (instead of
3225 - CONFIG_ENV_SECT_SIZE:
3227 Size of the sector containing the environment.
3230 b) Sometimes flash chips have few, equal sized, BIG sectors.
3231 In such a case you don't want to spend a whole sector for
3236 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3237 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3238 of this flash sector for the environment. This saves
3239 memory for the RAM copy of the environment.
3241 It may also save flash memory if you decide to use this
3242 when your environment is "embedded" within U-Boot code,
3243 since then the remainder of the flash sector could be used
3244 for U-Boot code. It should be pointed out that this is
3245 STRONGLY DISCOURAGED from a robustness point of view:
3246 updating the environment in flash makes it always
3247 necessary to erase the WHOLE sector. If something goes
3248 wrong before the contents has been restored from a copy in
3249 RAM, your target system will be dead.
3251 - CONFIG_ENV_ADDR_REDUND
3252 CONFIG_ENV_SIZE_REDUND
3254 These settings describe a second storage area used to hold
3255 a redundant copy of the environment data, so that there is
3256 a valid backup copy in case there is a power failure during
3257 a "saveenv" operation.
3259 BE CAREFUL! Any changes to the flash layout, and some changes to the
3260 source code will make it necessary to adapt <board>/u-boot.lds*
3264 - CONFIG_ENV_IS_IN_NVRAM:
3266 Define this if you have some non-volatile memory device
3267 (NVRAM, battery buffered SRAM) which you want to use for the
3273 These two #defines are used to determine the memory area you
3274 want to use for environment. It is assumed that this memory
3275 can just be read and written to, without any special
3278 BE CAREFUL! The first access to the environment happens quite early
3279 in U-Boot initalization (when we try to get the setting of for the
3280 console baudrate). You *MUST* have mapped your NVRAM area then, or
3283 Please note that even with NVRAM we still use a copy of the
3284 environment in RAM: we could work on NVRAM directly, but we want to
3285 keep settings there always unmodified except somebody uses "saveenv"
3286 to save the current settings.
3289 - CONFIG_ENV_IS_IN_EEPROM:
3291 Use this if you have an EEPROM or similar serial access
3292 device and a driver for it.
3294 - CONFIG_ENV_OFFSET:
3297 These two #defines specify the offset and size of the
3298 environment area within the total memory of your EEPROM.
3300 - CONFIG_SYS_I2C_EEPROM_ADDR:
3301 If defined, specified the chip address of the EEPROM device.
3302 The default address is zero.
3304 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3305 If defined, the number of bits used to address bytes in a
3306 single page in the EEPROM device. A 64 byte page, for example
3307 would require six bits.
3309 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3310 If defined, the number of milliseconds to delay between
3311 page writes. The default is zero milliseconds.
3313 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3314 The length in bytes of the EEPROM memory array address. Note
3315 that this is NOT the chip address length!
3317 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3318 EEPROM chips that implement "address overflow" are ones
3319 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3320 address and the extra bits end up in the "chip address" bit
3321 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3324 Note that we consider the length of the address field to
3325 still be one byte because the extra address bits are hidden
3326 in the chip address.
3328 - CONFIG_SYS_EEPROM_SIZE:
3329 The size in bytes of the EEPROM device.
3331 - CONFIG_ENV_EEPROM_IS_ON_I2C
3332 define this, if you have I2C and SPI activated, and your
3333 EEPROM, which holds the environment, is on the I2C bus.
3335 - CONFIG_I2C_ENV_EEPROM_BUS
3336 if you have an Environment on an EEPROM reached over
3337 I2C muxes, you can define here, how to reach this
3338 EEPROM. For example:
3340 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3342 EEPROM which holds the environment, is reached over
3343 a pca9547 i2c mux with address 0x70, channel 3.
3345 - CONFIG_ENV_IS_IN_DATAFLASH:
3347 Define this if you have a DataFlash memory device which you
3348 want to use for the environment.
3350 - CONFIG_ENV_OFFSET:
3354 These three #defines specify the offset and size of the
3355 environment area within the total memory of your DataFlash placed
3356 at the specified address.
3358 - CONFIG_ENV_IS_IN_REMOTE:
3360 Define this if you have a remote memory space which you
3361 want to use for the local device's environment.
3366 These two #defines specify the address and size of the
3367 environment area within the remote memory space. The
3368 local device can get the environment from remote memory
3369 space by SRIO or PCIE links.
3371 BE CAREFUL! For some special cases, the local device can not use
3372 "saveenv" command. For example, the local device will get the
3373 environment stored in a remote NOR flash by SRIO or PCIE link,
3374 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3376 - CONFIG_ENV_IS_IN_NAND:
3378 Define this if you have a NAND device which you want to use
3379 for the environment.
3381 - CONFIG_ENV_OFFSET:
3384 These two #defines specify the offset and size of the environment
3385 area within the first NAND device. CONFIG_ENV_OFFSET must be
3386 aligned to an erase block boundary.
3388 - CONFIG_ENV_OFFSET_REDUND (optional):
3390 This setting describes a second storage area of CONFIG_ENV_SIZE
3391 size used to hold a redundant copy of the environment data, so
3392 that there is a valid backup copy in case there is a power failure
3393 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3394 aligned to an erase block boundary.
3396 - CONFIG_ENV_RANGE (optional):
3398 Specifies the length of the region in which the environment
3399 can be written. This should be a multiple of the NAND device's
3400 block size. Specifying a range with more erase blocks than
3401 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3402 the range to be avoided.
3404 - CONFIG_ENV_OFFSET_OOB (optional):
3406 Enables support for dynamically retrieving the offset of the
3407 environment from block zero's out-of-band data. The
3408 "nand env.oob" command can be used to record this offset.
3409 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3410 using CONFIG_ENV_OFFSET_OOB.
3412 - CONFIG_NAND_ENV_DST
3414 Defines address in RAM to which the nand_spl code should copy the
3415 environment. If redundant environment is used, it will be copied to
3416 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3418 - CONFIG_SYS_SPI_INIT_OFFSET
3420 Defines offset to the initial SPI buffer area in DPRAM. The
3421 area is used at an early stage (ROM part) if the environment
3422 is configured to reside in the SPI EEPROM: We need a 520 byte
3423 scratch DPRAM area. It is used between the two initialization
3424 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3425 to be a good choice since it makes it far enough from the
3426 start of the data area as well as from the stack pointer.
3428 Please note that the environment is read-only until the monitor
3429 has been relocated to RAM and a RAM copy of the environment has been
3430 created; also, when using EEPROM you will have to use getenv_f()
3431 until then to read environment variables.
3433 The environment is protected by a CRC32 checksum. Before the monitor
3434 is relocated into RAM, as a result of a bad CRC you will be working
3435 with the compiled-in default environment - *silently*!!! [This is
3436 necessary, because the first environment variable we need is the
3437 "baudrate" setting for the console - if we have a bad CRC, we don't
3438 have any device yet where we could complain.]
3440 Note: once the monitor has been relocated, then it will complain if
3441 the default environment is used; a new CRC is computed as soon as you
3442 use the "saveenv" command to store a valid environment.
3444 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3445 Echo the inverted Ethernet link state to the fault LED.
3447 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3448 also needs to be defined.
3450 - CONFIG_SYS_FAULT_MII_ADDR:
3451 MII address of the PHY to check for the Ethernet link state.
3453 - CONFIG_NS16550_MIN_FUNCTIONS:
3454 Define this if you desire to only have use of the NS16550_init
3455 and NS16550_putc functions for the serial driver located at
3456 drivers/serial/ns16550.c. This option is useful for saving
3457 space for already greatly restricted images, including but not
3458 limited to NAND_SPL configurations.
3460 - CONFIG_DISPLAY_BOARDINFO
3461 Display information about the board that U-Boot is running on
3462 when U-Boot starts up. The board function checkboard() is called
3465 Low Level (hardware related) configuration options:
3466 ---------------------------------------------------
3468 - CONFIG_SYS_CACHELINE_SIZE:
3469 Cache Line Size of the CPU.
3471 - CONFIG_SYS_DEFAULT_IMMR:
3472 Default address of the IMMR after system reset.
3474 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3475 and RPXsuper) to be able to adjust the position of
3476 the IMMR register after a reset.
3478 - CONFIG_SYS_CCSRBAR_DEFAULT:
3479 Default (power-on reset) physical address of CCSR on Freescale
3482 - CONFIG_SYS_CCSRBAR:
3483 Virtual address of CCSR. On a 32-bit build, this is typically
3484 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3486 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3487 for cross-platform code that uses that macro instead.
3489 - CONFIG_SYS_CCSRBAR_PHYS:
3490 Physical address of CCSR. CCSR can be relocated to a new
3491 physical address, if desired. In this case, this macro should
3492 be set to that address. Otherwise, it should be set to the
3493 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3494 is typically relocated on 36-bit builds. It is recommended
3495 that this macro be defined via the _HIGH and _LOW macros:
3497 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3498 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3500 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3501 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3502 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3503 used in assembly code, so it must not contain typecasts or
3504 integer size suffixes (e.g. "ULL").
3506 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3507 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3508 used in assembly code, so it must not contain typecasts or
3509 integer size suffixes (e.g. "ULL").
3511 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3512 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3513 forced to a value that ensures that CCSR is not relocated.
3515 - Floppy Disk Support:
3516 CONFIG_SYS_FDC_DRIVE_NUMBER
3518 the default drive number (default value 0)
3520 CONFIG_SYS_ISA_IO_STRIDE
3522 defines the spacing between FDC chipset registers
3525 CONFIG_SYS_ISA_IO_OFFSET
3527 defines the offset of register from address. It
3528 depends on which part of the data bus is connected to
3529 the FDC chipset. (default value 0)
3531 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3532 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3535 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3536 fdc_hw_init() is called at the beginning of the FDC
3537 setup. fdc_hw_init() must be provided by the board
3538 source code. It is used to make hardware dependant
3542 Most IDE controllers were designed to be connected with PCI
3543 interface. Only few of them were designed for AHB interface.
3544 When software is doing ATA command and data transfer to
3545 IDE devices through IDE-AHB controller, some additional
3546 registers accessing to these kind of IDE-AHB controller
3549 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3550 DO NOT CHANGE unless you know exactly what you're
3551 doing! (11-4) [MPC8xx/82xx systems only]
3553 - CONFIG_SYS_INIT_RAM_ADDR:
3555 Start address of memory area that can be used for
3556 initial data and stack; please note that this must be
3557 writable memory that is working WITHOUT special
3558 initialization, i. e. you CANNOT use normal RAM which
3559 will become available only after programming the
3560 memory controller and running certain initialization
3563 U-Boot uses the following memory types:
3564 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3565 - MPC824X: data cache
3566 - PPC4xx: data cache
3568 - CONFIG_SYS_GBL_DATA_OFFSET:
3570 Offset of the initial data structure in the memory
3571 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3572 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3573 data is located at the end of the available space
3574 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3575 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3576 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3577 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3580 On the MPC824X (or other systems that use the data
3581 cache for initial memory) the address chosen for
3582 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3583 point to an otherwise UNUSED address space between
3584 the top of RAM and the start of the PCI space.
3586 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3588 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3590 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3592 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3594 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3596 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3598 - CONFIG_SYS_OR_TIMING_SDRAM:
3601 - CONFIG_SYS_MAMR_PTA:
3602 periodic timer for refresh
3604 - CONFIG_SYS_DER: Debug Event Register (37-47)
3606 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3607 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3608 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3609 CONFIG_SYS_BR1_PRELIM:
3610 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3612 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3613 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3614 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3615 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3617 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3618 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3619 Machine Mode Register and Memory Periodic Timer
3620 Prescaler definitions (SDRAM timing)
3622 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3623 enable I2C microcode relocation patch (MPC8xx);
3624 define relocation offset in DPRAM [DSP2]
3626 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3627 enable SMC microcode relocation patch (MPC8xx);
3628 define relocation offset in DPRAM [SMC1]
3630 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3631 enable SPI microcode relocation patch (MPC8xx);
3632 define relocation offset in DPRAM [SCC4]
3634 - CONFIG_SYS_USE_OSCCLK:
3635 Use OSCM clock mode on MBX8xx board. Be careful,
3636 wrong setting might damage your board. Read
3637 doc/README.MBX before setting this variable!
3639 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3640 Offset of the bootmode word in DPRAM used by post
3641 (Power On Self Tests). This definition overrides
3642 #define'd default value in commproc.h resp.
3645 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3646 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3647 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3648 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3649 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3650 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3651 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3652 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3653 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3655 - CONFIG_PCI_DISABLE_PCIE:
3656 Disable PCI-Express on systems where it is supported but not
3659 - CONFIG_PCI_ENUM_ONLY
3660 Only scan through and get the devices on the busses.
3661 Don't do any setup work, presumably because someone or
3662 something has already done it, and we don't need to do it
3663 a second time. Useful for platforms that are pre-booted
3664 by coreboot or similar.
3667 Chip has SRIO or not
3670 Board has SRIO 1 port available
3673 Board has SRIO 2 port available
3675 - CONFIG_SYS_SRIOn_MEM_VIRT:
3676 Virtual Address of SRIO port 'n' memory region
3678 - CONFIG_SYS_SRIOn_MEM_PHYS:
3679 Physical Address of SRIO port 'n' memory region
3681 - CONFIG_SYS_SRIOn_MEM_SIZE:
3682 Size of SRIO port 'n' memory region
3684 - CONFIG_SYS_NDFC_16
3685 Defined to tell the NDFC that the NAND chip is using a
3688 - CONFIG_SYS_NDFC_EBC0_CFG
3689 Sets the EBC0_CFG register for the NDFC. If not defined
3690 a default value will be used.
3693 Get DDR timing information from an I2C EEPROM. Common
3694 with pluggable memory modules such as SODIMMs
3697 I2C address of the SPD EEPROM
3699 - CONFIG_SYS_SPD_BUS_NUM
3700 If SPD EEPROM is on an I2C bus other than the first
3701 one, specify here. Note that the value must resolve
3702 to something your driver can deal with.
3704 - CONFIG_SYS_DDR_RAW_TIMING
3705 Get DDR timing information from other than SPD. Common with
3706 soldered DDR chips onboard without SPD. DDR raw timing
3707 parameters are extracted from datasheet and hard-coded into
3708 header files or board specific files.
3710 - CONFIG_FSL_DDR_INTERACTIVE
3711 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3713 - CONFIG_SYS_83XX_DDR_USES_CS0
3714 Only for 83xx systems. If specified, then DDR should
3715 be configured using CS0 and CS1 instead of CS2 and CS3.
3717 - CONFIG_ETHER_ON_FEC[12]
3718 Define to enable FEC[12] on a 8xx series processor.
3720 - CONFIG_FEC[12]_PHY
3721 Define to the hardcoded PHY address which corresponds
3722 to the given FEC; i. e.
3723 #define CONFIG_FEC1_PHY 4
3724 means that the PHY with address 4 is connected to FEC1
3726 When set to -1, means to probe for first available.
3728 - CONFIG_FEC[12]_PHY_NORXERR
3729 The PHY does not have a RXERR line (RMII only).
3730 (so program the FEC to ignore it).
3733 Enable RMII mode for all FECs.
3734 Note that this is a global option, we can't
3735 have one FEC in standard MII mode and another in RMII mode.
3737 - CONFIG_CRC32_VERIFY
3738 Add a verify option to the crc32 command.
3741 => crc32 -v <address> <count> <crc32>
3743 Where address/count indicate a memory area
3744 and crc32 is the correct crc32 which the
3748 Add the "loopw" memory command. This only takes effect if
3749 the memory commands are activated globally (CONFIG_CMD_MEM).
3752 Add the "mdc" and "mwc" memory commands. These are cyclic
3757 This command will print 4 bytes (10,11,12,13) each 500 ms.
3759 => mwc.l 100 12345678 10
3760 This command will write 12345678 to address 100 all 10 ms.
3762 This only takes effect if the memory commands are activated
3763 globally (CONFIG_CMD_MEM).
3765 - CONFIG_SKIP_LOWLEVEL_INIT
3766 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3767 low level initializations (like setting up the memory
3768 controller) are omitted and/or U-Boot does not
3769 relocate itself into RAM.
3771 Normally this variable MUST NOT be defined. The only
3772 exception is when U-Boot is loaded (to RAM) by some
3773 other boot loader or by a debugger which performs
3774 these initializations itself.
3777 Modifies the behaviour of start.S when compiling a loader
3778 that is executed before the actual U-Boot. E.g. when
3779 compiling a NAND SPL.
3781 - CONFIG_USE_ARCH_MEMCPY
3782 CONFIG_USE_ARCH_MEMSET
3783 If these options are used a optimized version of memcpy/memset will
3784 be used if available. These functions may be faster under some
3785 conditions but may increase the binary size.
3787 - CONFIG_X86_NO_RESET_VECTOR
3788 If defined, the x86 reset vector code is excluded. You will need
3789 to do this when U-Boot is running from Coreboot.
3791 - CONFIG_X86_NO_REAL_MODE
3792 If defined, x86 real mode code is omitted. This assumes a
3793 32-bit environment where such code is not needed. You will
3794 need to do this when U-Boot is running from Coreboot.
3797 Freescale QE/FMAN Firmware Support:
3798 -----------------------------------
3800 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3801 loading of "firmware", which is encoded in the QE firmware binary format.
3802 This firmware often needs to be loaded during U-Boot booting, so macros
3803 are used to identify the storage device (NOR flash, SPI, etc) and the address
3806 - CONFIG_SYS_QE_FMAN_FW_ADDR
3807 The address in the storage device where the firmware is located. The
3808 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3811 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3812 The maximum possible size of the firmware. The firmware binary format
3813 has a field that specifies the actual size of the firmware, but it
3814 might not be possible to read any part of the firmware unless some
3815 local storage is allocated to hold the entire firmware first.
3817 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3818 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3819 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3820 virtual address in NOR flash.
3822 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3823 Specifies that QE/FMAN firmware is located in NAND flash.
3824 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3826 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3827 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3828 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3830 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3831 Specifies that QE/FMAN firmware is located on the primary SPI
3832 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3834 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3835 Specifies that QE/FMAN firmware is located in the remote (master)
3836 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3837 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3838 window->master inbound window->master LAW->the ucode address in
3839 master's memory space.
3841 Building the Software:
3842 ======================
3844 Building U-Boot has been tested in several native build environments
3845 and in many different cross environments. Of course we cannot support
3846 all possibly existing versions of cross development tools in all
3847 (potentially obsolete) versions. In case of tool chain problems we
3848 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3849 which is extensively used to build and test U-Boot.
3851 If you are not using a native environment, it is assumed that you
3852 have GNU cross compiling tools available in your path. In this case,
3853 you must set the environment variable CROSS_COMPILE in your shell.
3854 Note that no changes to the Makefile or any other source files are
3855 necessary. For example using the ELDK on a 4xx CPU, please enter:
3857 $ CROSS_COMPILE=ppc_4xx-
3858 $ export CROSS_COMPILE
3860 Note: If you wish to generate Windows versions of the utilities in
3861 the tools directory you can use the MinGW toolchain
3862 (http://www.mingw.org). Set your HOST tools to the MinGW
3863 toolchain and execute 'make tools'. For example:
3865 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3867 Binaries such as tools/mkimage.exe will be created which can
3868 be executed on computers running Windows.
3870 U-Boot is intended to be simple to build. After installing the
3871 sources you must configure U-Boot for one specific board type. This
3876 where "NAME_config" is the name of one of the existing configu-
3877 rations; see boards.cfg for supported names.
3879 Note: for some board special configuration names may exist; check if
3880 additional information is available from the board vendor; for
3881 instance, the TQM823L systems are available without (standard)
3882 or with LCD support. You can select such additional "features"
3883 when choosing the configuration, i. e.
3886 - will configure for a plain TQM823L, i. e. no LCD support
3888 make TQM823L_LCD_config
3889 - will configure for a TQM823L with U-Boot console on LCD
3894 Finally, type "make all", and you should get some working U-Boot
3895 images ready for download to / installation on your system:
3897 - "u-boot.bin" is a raw binary image
3898 - "u-boot" is an image in ELF binary format
3899 - "u-boot.srec" is in Motorola S-Record format
3901 By default the build is performed locally and the objects are saved
3902 in the source directory. One of the two methods can be used to change
3903 this behavior and build U-Boot to some external directory:
3905 1. Add O= to the make command line invocations:
3907 make O=/tmp/build distclean
3908 make O=/tmp/build NAME_config
3909 make O=/tmp/build all
3911 2. Set environment variable BUILD_DIR to point to the desired location:
3913 export BUILD_DIR=/tmp/build
3918 Note that the command line "O=" setting overrides the BUILD_DIR environment
3922 Please be aware that the Makefiles assume you are using GNU make, so
3923 for instance on NetBSD you might need to use "gmake" instead of
3927 If the system board that you have is not listed, then you will need
3928 to port U-Boot to your hardware platform. To do this, follow these
3931 1. Add a new configuration option for your board to the toplevel
3932 "boards.cfg" file, using the existing entries as examples.
3933 Follow the instructions there to keep the boards in order.
3934 2. Create a new directory to hold your board specific code. Add any
3935 files you need. In your board directory, you will need at least
3936 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3937 3. Create a new configuration file "include/configs/<board>.h" for
3939 3. If you're porting U-Boot to a new CPU, then also create a new
3940 directory to hold your CPU specific code. Add any files you need.
3941 4. Run "make <board>_config" with your new name.
3942 5. Type "make", and you should get a working "u-boot.srec" file
3943 to be installed on your target system.
3944 6. Debug and solve any problems that might arise.
3945 [Of course, this last step is much harder than it sounds.]
3948 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3949 ==============================================================
3951 If you have modified U-Boot sources (for instance added a new board
3952 or support for new devices, a new CPU, etc.) you are expected to
3953 provide feedback to the other developers. The feedback normally takes
3954 the form of a "patch", i. e. a context diff against a certain (latest
3955 official or latest in the git repository) version of U-Boot sources.
3957 But before you submit such a patch, please verify that your modifi-
3958 cation did not break existing code. At least make sure that *ALL* of
3959 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3960 just run the "MAKEALL" script, which will configure and build U-Boot
3961 for ALL supported system. Be warned, this will take a while. You can
3962 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3963 environment variable to the script, i. e. to use the ELDK cross tools
3966 CROSS_COMPILE=ppc_8xx- MAKEALL
3968 or to build on a native PowerPC system you can type
3970 CROSS_COMPILE=' ' MAKEALL
3972 When using the MAKEALL script, the default behaviour is to build
3973 U-Boot in the source directory. This location can be changed by
3974 setting the BUILD_DIR environment variable. Also, for each target
3975 built, the MAKEALL script saves two log files (<target>.ERR and
3976 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3977 location can be changed by setting the MAKEALL_LOGDIR environment
3978 variable. For example:
3980 export BUILD_DIR=/tmp/build
3981 export MAKEALL_LOGDIR=/tmp/log
3982 CROSS_COMPILE=ppc_8xx- MAKEALL
3984 With the above settings build objects are saved in the /tmp/build,
3985 log files are saved in the /tmp/log and the source tree remains clean
3986 during the whole build process.
3989 See also "U-Boot Porting Guide" below.
3992 Monitor Commands - Overview:
3993 ============================
3995 go - start application at address 'addr'
3996 run - run commands in an environment variable
3997 bootm - boot application image from memory
3998 bootp - boot image via network using BootP/TFTP protocol
3999 bootz - boot zImage from memory
4000 tftpboot- boot image via network using TFTP protocol
4001 and env variables "ipaddr" and "serverip"
4002 (and eventually "gatewayip")
4003 tftpput - upload a file via network using TFTP protocol
4004 rarpboot- boot image via network using RARP/TFTP protocol
4005 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4006 loads - load S-Record file over serial line
4007 loadb - load binary file over serial line (kermit mode)
4009 mm - memory modify (auto-incrementing)
4010 nm - memory modify (constant address)
4011 mw - memory write (fill)
4013 cmp - memory compare
4014 crc32 - checksum calculation
4015 i2c - I2C sub-system
4016 sspi - SPI utility commands
4017 base - print or set address offset
4018 printenv- print environment variables
4019 setenv - set environment variables
4020 saveenv - save environment variables to persistent storage
4021 protect - enable or disable FLASH write protection
4022 erase - erase FLASH memory
4023 flinfo - print FLASH memory information
4024 nand - NAND memory operations (see doc/README.nand)
4025 bdinfo - print Board Info structure
4026 iminfo - print header information for application image
4027 coninfo - print console devices and informations
4028 ide - IDE sub-system
4029 loop - infinite loop on address range
4030 loopw - infinite write loop on address range
4031 mtest - simple RAM test
4032 icache - enable or disable instruction cache
4033 dcache - enable or disable data cache
4034 reset - Perform RESET of the CPU
4035 echo - echo args to console
4036 version - print monitor version
4037 help - print online help
4038 ? - alias for 'help'
4041 Monitor Commands - Detailed Description:
4042 ========================================
4046 For now: just type "help <command>".
4049 Environment Variables:
4050 ======================
4052 U-Boot supports user configuration using Environment Variables which
4053 can be made persistent by saving to Flash memory.
4055 Environment Variables are set using "setenv", printed using
4056 "printenv", and saved to Flash using "saveenv". Using "setenv"
4057 without a value can be used to delete a variable from the
4058 environment. As long as you don't save the environment you are
4059 working with an in-memory copy. In case the Flash area containing the
4060 environment is erased by accident, a default environment is provided.
4062 Some configuration options can be set using Environment Variables.
4064 List of environment variables (most likely not complete):
4066 baudrate - see CONFIG_BAUDRATE
4068 bootdelay - see CONFIG_BOOTDELAY
4070 bootcmd - see CONFIG_BOOTCOMMAND
4072 bootargs - Boot arguments when booting an RTOS image
4074 bootfile - Name of the image to load with TFTP
4076 bootm_low - Memory range available for image processing in the bootm
4077 command can be restricted. This variable is given as
4078 a hexadecimal number and defines lowest address allowed
4079 for use by the bootm command. See also "bootm_size"
4080 environment variable. Address defined by "bootm_low" is
4081 also the base of the initial memory mapping for the Linux
4082 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4085 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4086 This variable is given as a hexadecimal number and it
4087 defines the size of the memory region starting at base
4088 address bootm_low that is accessible by the Linux kernel
4089 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4090 as the default value if it is defined, and bootm_size is
4093 bootm_size - Memory range available for image processing in the bootm
4094 command can be restricted. This variable is given as
4095 a hexadecimal number and defines the size of the region
4096 allowed for use by the bootm command. See also "bootm_low"
4097 environment variable.
4099 updatefile - Location of the software update file on a TFTP server, used
4100 by the automatic software update feature. Please refer to
4101 documentation in doc/README.update for more details.
4103 autoload - if set to "no" (any string beginning with 'n'),
4104 "bootp" will just load perform a lookup of the
4105 configuration from the BOOTP server, but not try to
4106 load any image using TFTP
4108 autostart - if set to "yes", an image loaded using the "bootp",
4109 "rarpboot", "tftpboot" or "diskboot" commands will
4110 be automatically started (by internally calling
4113 If set to "no", a standalone image passed to the
4114 "bootm" command will be copied to the load address
4115 (and eventually uncompressed), but NOT be started.
4116 This can be used to load and uncompress arbitrary
4119 fdt_high - if set this restricts the maximum address that the
4120 flattened device tree will be copied into upon boot.
4121 For example, if you have a system with 1 GB memory
4122 at physical address 0x10000000, while Linux kernel
4123 only recognizes the first 704 MB as low memory, you
4124 may need to set fdt_high as 0x3C000000 to have the
4125 device tree blob be copied to the maximum address
4126 of the 704 MB low memory, so that Linux kernel can
4127 access it during the boot procedure.
4129 If this is set to the special value 0xFFFFFFFF then
4130 the fdt will not be copied at all on boot. For this
4131 to work it must reside in writable memory, have
4132 sufficient padding on the end of it for u-boot to
4133 add the information it needs into it, and the memory
4134 must be accessible by the kernel.
4136 fdtcontroladdr- if set this is the address of the control flattened
4137 device tree used by U-Boot when CONFIG_OF_CONTROL is
4140 i2cfast - (PPC405GP|PPC405EP only)
4141 if set to 'y' configures Linux I2C driver for fast
4142 mode (400kHZ). This environment variable is used in
4143 initialization code. So, for changes to be effective
4144 it must be saved and board must be reset.
4146 initrd_high - restrict positioning of initrd images:
4147 If this variable is not set, initrd images will be
4148 copied to the highest possible address in RAM; this
4149 is usually what you want since it allows for
4150 maximum initrd size. If for some reason you want to
4151 make sure that the initrd image is loaded below the
4152 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4153 variable to a value of "no" or "off" or "0".
4154 Alternatively, you can set it to a maximum upper
4155 address to use (U-Boot will still check that it
4156 does not overwrite the U-Boot stack and data).
4158 For instance, when you have a system with 16 MB
4159 RAM, and want to reserve 4 MB from use by Linux,
4160 you can do this by adding "mem=12M" to the value of
4161 the "bootargs" variable. However, now you must make
4162 sure that the initrd image is placed in the first
4163 12 MB as well - this can be done with
4165 setenv initrd_high 00c00000
4167 If you set initrd_high to 0xFFFFFFFF, this is an
4168 indication to U-Boot that all addresses are legal
4169 for the Linux kernel, including addresses in flash
4170 memory. In this case U-Boot will NOT COPY the
4171 ramdisk at all. This may be useful to reduce the
4172 boot time on your system, but requires that this
4173 feature is supported by your Linux kernel.
4175 ipaddr - IP address; needed for tftpboot command
4177 loadaddr - Default load address for commands like "bootp",
4178 "rarpboot", "tftpboot", "loadb" or "diskboot"
4180 loads_echo - see CONFIG_LOADS_ECHO
4182 serverip - TFTP server IP address; needed for tftpboot command
4184 bootretry - see CONFIG_BOOT_RETRY_TIME
4186 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4188 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4190 ethprime - controls which interface is used first.
4192 ethact - controls which interface is currently active.
4193 For example you can do the following
4195 => setenv ethact FEC
4196 => ping 192.168.0.1 # traffic sent on FEC
4197 => setenv ethact SCC
4198 => ping 10.0.0.1 # traffic sent on SCC
4200 ethrotate - When set to "no" U-Boot does not go through all
4201 available network interfaces.
4202 It just stays at the currently selected interface.
4204 netretry - When set to "no" each network operation will
4205 either succeed or fail without retrying.
4206 When set to "once" the network operation will
4207 fail when all the available network interfaces
4208 are tried once without success.
4209 Useful on scripts which control the retry operation
4212 npe_ucode - set load address for the NPE microcode
4214 tftpsrcport - If this is set, the value is used for TFTP's
4217 tftpdstport - If this is set, the value is used for TFTP's UDP
4218 destination port instead of the Well Know Port 69.
4220 tftpblocksize - Block size to use for TFTP transfers; if not set,
4221 we use the TFTP server's default block size
4223 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4224 seconds, minimum value is 1000 = 1 second). Defines
4225 when a packet is considered to be lost so it has to
4226 be retransmitted. The default is 5000 = 5 seconds.
4227 Lowering this value may make downloads succeed
4228 faster in networks with high packet loss rates or
4229 with unreliable TFTP servers.
4231 vlan - When set to a value < 4095 the traffic over
4232 Ethernet is encapsulated/received over 802.1q
4235 The following image location variables contain the location of images
4236 used in booting. The "Image" column gives the role of the image and is
4237 not an environment variable name. The other columns are environment
4238 variable names. "File Name" gives the name of the file on a TFTP
4239 server, "RAM Address" gives the location in RAM the image will be
4240 loaded to, and "Flash Location" gives the image's address in NOR
4241 flash or offset in NAND flash.
4243 *Note* - these variables don't have to be defined for all boards, some
4244 boards currenlty use other variables for these purposes, and some
4245 boards use these variables for other purposes.
4247 Image File Name RAM Address Flash Location
4248 ----- --------- ----------- --------------
4249 u-boot u-boot u-boot_addr_r u-boot_addr
4250 Linux kernel bootfile kernel_addr_r kernel_addr
4251 device tree blob fdtfile fdt_addr_r fdt_addr
4252 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4254 The following environment variables may be used and automatically
4255 updated by the network boot commands ("bootp" and "rarpboot"),
4256 depending the information provided by your boot server:
4258 bootfile - see above
4259 dnsip - IP address of your Domain Name Server
4260 dnsip2 - IP address of your secondary Domain Name Server
4261 gatewayip - IP address of the Gateway (Router) to use
4262 hostname - Target hostname
4264 netmask - Subnet Mask
4265 rootpath - Pathname of the root filesystem on the NFS server
4266 serverip - see above
4269 There are two special Environment Variables:
4271 serial# - contains hardware identification information such
4272 as type string and/or serial number
4273 ethaddr - Ethernet address
4275 These variables can be set only once (usually during manufacturing of
4276 the board). U-Boot refuses to delete or overwrite these variables
4277 once they have been set once.
4280 Further special Environment Variables:
4282 ver - Contains the U-Boot version string as printed
4283 with the "version" command. This variable is
4284 readonly (see CONFIG_VERSION_VARIABLE).
4287 Please note that changes to some configuration parameters may take
4288 only effect after the next boot (yes, that's just like Windoze :-).
4291 Callback functions for environment variables:
4292 ---------------------------------------------
4294 For some environment variables, the behavior of u-boot needs to change
4295 when their values are changed. This functionailty allows functions to
4296 be associated with arbitrary variables. On creation, overwrite, or
4297 deletion, the callback will provide the opportunity for some side
4298 effect to happen or for the change to be rejected.
4300 The callbacks are named and associated with a function using the
4301 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4303 These callbacks are associated with variables in one of two ways. The
4304 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4305 in the board configuration to a string that defines a list of
4306 associations. The list must be in the following format:
4308 entry = variable_name[:callback_name]
4311 If the callback name is not specified, then the callback is deleted.
4312 Spaces are also allowed anywhere in the list.
4314 Callbacks can also be associated by defining the ".callbacks" variable
4315 with the same list format above. Any association in ".callbacks" will
4316 override any association in the static list. You can define
4317 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4318 ".callbacks" envirnoment variable in the default or embedded environment.
4321 Command Line Parsing:
4322 =====================
4324 There are two different command line parsers available with U-Boot:
4325 the old "simple" one, and the much more powerful "hush" shell:
4327 Old, simple command line parser:
4328 --------------------------------
4330 - supports environment variables (through setenv / saveenv commands)
4331 - several commands on one line, separated by ';'
4332 - variable substitution using "... ${name} ..." syntax
4333 - special characters ('$', ';') can be escaped by prefixing with '\',
4335 setenv bootcmd bootm \${address}
4336 - You can also escape text by enclosing in single apostrophes, for example:
4337 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4342 - similar to Bourne shell, with control structures like
4343 if...then...else...fi, for...do...done; while...do...done,
4344 until...do...done, ...
4345 - supports environment ("global") variables (through setenv / saveenv
4346 commands) and local shell variables (through standard shell syntax
4347 "name=value"); only environment variables can be used with "run"
4353 (1) If a command line (or an environment variable executed by a "run"
4354 command) contains several commands separated by semicolon, and
4355 one of these commands fails, then the remaining commands will be
4358 (2) If you execute several variables with one call to run (i. e.
4359 calling run with a list of variables as arguments), any failing
4360 command will cause "run" to terminate, i. e. the remaining
4361 variables are not executed.
4363 Note for Redundant Ethernet Interfaces:
4364 =======================================
4366 Some boards come with redundant Ethernet interfaces; U-Boot supports
4367 such configurations and is capable of automatic selection of a
4368 "working" interface when needed. MAC assignment works as follows:
4370 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4371 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4372 "eth1addr" (=>eth1), "eth2addr", ...
4374 If the network interface stores some valid MAC address (for instance
4375 in SROM), this is used as default address if there is NO correspon-
4376 ding setting in the environment; if the corresponding environment
4377 variable is set, this overrides the settings in the card; that means:
4379 o If the SROM has a valid MAC address, and there is no address in the
4380 environment, the SROM's address is used.
4382 o If there is no valid address in the SROM, and a definition in the
4383 environment exists, then the value from the environment variable is
4386 o If both the SROM and the environment contain a MAC address, and
4387 both addresses are the same, this MAC address is used.
4389 o If both the SROM and the environment contain a MAC address, and the
4390 addresses differ, the value from the environment is used and a
4393 o If neither SROM nor the environment contain a MAC address, an error
4396 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4397 will be programmed into hardware as part of the initialization process. This
4398 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4399 The naming convention is as follows:
4400 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4405 U-Boot is capable of booting (and performing other auxiliary operations on)
4406 images in two formats:
4408 New uImage format (FIT)
4409 -----------------------
4411 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4412 to Flattened Device Tree). It allows the use of images with multiple
4413 components (several kernels, ramdisks, etc.), with contents protected by
4414 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4420 Old image format is based on binary files which can be basically anything,
4421 preceded by a special header; see the definitions in include/image.h for
4422 details; basically, the header defines the following image properties:
4424 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4425 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4426 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4427 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4429 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4430 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4431 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4432 * Compression Type (uncompressed, gzip, bzip2)
4438 The header is marked by a special Magic Number, and both the header
4439 and the data portions of the image are secured against corruption by
4446 Although U-Boot should support any OS or standalone application
4447 easily, the main focus has always been on Linux during the design of
4450 U-Boot includes many features that so far have been part of some
4451 special "boot loader" code within the Linux kernel. Also, any
4452 "initrd" images to be used are no longer part of one big Linux image;
4453 instead, kernel and "initrd" are separate images. This implementation
4454 serves several purposes:
4456 - the same features can be used for other OS or standalone
4457 applications (for instance: using compressed images to reduce the
4458 Flash memory footprint)
4460 - it becomes much easier to port new Linux kernel versions because
4461 lots of low-level, hardware dependent stuff are done by U-Boot
4463 - the same Linux kernel image can now be used with different "initrd"
4464 images; of course this also means that different kernel images can
4465 be run with the same "initrd". This makes testing easier (you don't
4466 have to build a new "zImage.initrd" Linux image when you just
4467 change a file in your "initrd"). Also, a field-upgrade of the
4468 software is easier now.
4474 Porting Linux to U-Boot based systems:
4475 ---------------------------------------
4477 U-Boot cannot save you from doing all the necessary modifications to
4478 configure the Linux device drivers for use with your target hardware
4479 (no, we don't intend to provide a full virtual machine interface to
4482 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4484 Just make sure your machine specific header file (for instance
4485 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4486 Information structure as we define in include/asm-<arch>/u-boot.h,
4487 and make sure that your definition of IMAP_ADDR uses the same value
4488 as your U-Boot configuration in CONFIG_SYS_IMMR.
4491 Configuring the Linux kernel:
4492 -----------------------------
4494 No specific requirements for U-Boot. Make sure you have some root
4495 device (initial ramdisk, NFS) for your target system.
4498 Building a Linux Image:
4499 -----------------------
4501 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4502 not used. If you use recent kernel source, a new build target
4503 "uImage" will exist which automatically builds an image usable by
4504 U-Boot. Most older kernels also have support for a "pImage" target,
4505 which was introduced for our predecessor project PPCBoot and uses a
4506 100% compatible format.
4515 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4516 encapsulate a compressed Linux kernel image with header information,
4517 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4519 * build a standard "vmlinux" kernel image (in ELF binary format):
4521 * convert the kernel into a raw binary image:
4523 ${CROSS_COMPILE}-objcopy -O binary \
4524 -R .note -R .comment \
4525 -S vmlinux linux.bin
4527 * compress the binary image:
4531 * package compressed binary image for U-Boot:
4533 mkimage -A ppc -O linux -T kernel -C gzip \
4534 -a 0 -e 0 -n "Linux Kernel Image" \
4535 -d linux.bin.gz uImage
4538 The "mkimage" tool can also be used to create ramdisk images for use
4539 with U-Boot, either separated from the Linux kernel image, or
4540 combined into one file. "mkimage" encapsulates the images with a 64
4541 byte header containing information about target architecture,
4542 operating system, image type, compression method, entry points, time
4543 stamp, CRC32 checksums, etc.
4545 "mkimage" can be called in two ways: to verify existing images and
4546 print the header information, or to build new images.
4548 In the first form (with "-l" option) mkimage lists the information
4549 contained in the header of an existing U-Boot image; this includes
4550 checksum verification:
4552 tools/mkimage -l image
4553 -l ==> list image header information
4555 The second form (with "-d" option) is used to build a U-Boot image
4556 from a "data file" which is used as image payload:
4558 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4559 -n name -d data_file image
4560 -A ==> set architecture to 'arch'
4561 -O ==> set operating system to 'os'
4562 -T ==> set image type to 'type'
4563 -C ==> set compression type 'comp'
4564 -a ==> set load address to 'addr' (hex)
4565 -e ==> set entry point to 'ep' (hex)
4566 -n ==> set image name to 'name'
4567 -d ==> use image data from 'datafile'
4569 Right now, all Linux kernels for PowerPC systems use the same load
4570 address (0x00000000), but the entry point address depends on the
4573 - 2.2.x kernels have the entry point at 0x0000000C,
4574 - 2.3.x and later kernels have the entry point at 0x00000000.
4576 So a typical call to build a U-Boot image would read:
4578 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4579 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4580 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4581 > examples/uImage.TQM850L
4582 Image Name: 2.4.4 kernel for TQM850L
4583 Created: Wed Jul 19 02:34:59 2000
4584 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4585 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4586 Load Address: 0x00000000
4587 Entry Point: 0x00000000
4589 To verify the contents of the image (or check for corruption):
4591 -> tools/mkimage -l examples/uImage.TQM850L
4592 Image Name: 2.4.4 kernel for TQM850L
4593 Created: Wed Jul 19 02:34:59 2000
4594 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4595 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4596 Load Address: 0x00000000
4597 Entry Point: 0x00000000
4599 NOTE: for embedded systems where boot time is critical you can trade
4600 speed for memory and install an UNCOMPRESSED image instead: this
4601 needs more space in Flash, but boots much faster since it does not
4602 need to be uncompressed:
4604 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4605 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4606 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4607 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4608 > examples/uImage.TQM850L-uncompressed
4609 Image Name: 2.4.4 kernel for TQM850L
4610 Created: Wed Jul 19 02:34:59 2000
4611 Image Type: PowerPC Linux Kernel Image (uncompressed)
4612 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4613 Load Address: 0x00000000
4614 Entry Point: 0x00000000
4617 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4618 when your kernel is intended to use an initial ramdisk:
4620 -> tools/mkimage -n 'Simple Ramdisk Image' \
4621 > -A ppc -O linux -T ramdisk -C gzip \
4622 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4623 Image Name: Simple Ramdisk Image
4624 Created: Wed Jan 12 14:01:50 2000
4625 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4626 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4627 Load Address: 0x00000000
4628 Entry Point: 0x00000000
4631 Installing a Linux Image:
4632 -------------------------
4634 To downloading a U-Boot image over the serial (console) interface,
4635 you must convert the image to S-Record format:
4637 objcopy -I binary -O srec examples/image examples/image.srec
4639 The 'objcopy' does not understand the information in the U-Boot
4640 image header, so the resulting S-Record file will be relative to
4641 address 0x00000000. To load it to a given address, you need to
4642 specify the target address as 'offset' parameter with the 'loads'
4645 Example: install the image to address 0x40100000 (which on the
4646 TQM8xxL is in the first Flash bank):
4648 => erase 40100000 401FFFFF
4654 ## Ready for S-Record download ...
4655 ~>examples/image.srec
4656 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4658 15989 15990 15991 15992
4659 [file transfer complete]
4661 ## Start Addr = 0x00000000
4664 You can check the success of the download using the 'iminfo' command;
4665 this includes a checksum verification so you can be sure no data
4666 corruption happened:
4670 ## Checking Image at 40100000 ...
4671 Image Name: 2.2.13 for initrd on TQM850L
4672 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4673 Data Size: 335725 Bytes = 327 kB = 0 MB
4674 Load Address: 00000000
4675 Entry Point: 0000000c
4676 Verifying Checksum ... OK
4682 The "bootm" command is used to boot an application that is stored in
4683 memory (RAM or Flash). In case of a Linux kernel image, the contents
4684 of the "bootargs" environment variable is passed to the kernel as
4685 parameters. You can check and modify this variable using the
4686 "printenv" and "setenv" commands:
4689 => printenv bootargs
4690 bootargs=root=/dev/ram
4692 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4694 => printenv bootargs
4695 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4698 ## Booting Linux kernel at 40020000 ...
4699 Image Name: 2.2.13 for NFS on TQM850L
4700 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4701 Data Size: 381681 Bytes = 372 kB = 0 MB
4702 Load Address: 00000000
4703 Entry Point: 0000000c
4704 Verifying Checksum ... OK
4705 Uncompressing Kernel Image ... OK
4706 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
4707 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4708 time_init: decrementer frequency = 187500000/60
4709 Calibrating delay loop... 49.77 BogoMIPS
4710 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4713 If you want to boot a Linux kernel with initial RAM disk, you pass
4714 the memory addresses of both the kernel and the initrd image (PPBCOOT
4715 format!) to the "bootm" command:
4717 => imi 40100000 40200000
4719 ## Checking Image at 40100000 ...
4720 Image Name: 2.2.13 for initrd on TQM850L
4721 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4722 Data Size: 335725 Bytes = 327 kB = 0 MB
4723 Load Address: 00000000
4724 Entry Point: 0000000c
4725 Verifying Checksum ... OK
4727 ## Checking Image at 40200000 ...
4728 Image Name: Simple Ramdisk Image
4729 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4730 Data Size: 566530 Bytes = 553 kB = 0 MB
4731 Load Address: 00000000
4732 Entry Point: 00000000
4733 Verifying Checksum ... OK
4735 => bootm 40100000 40200000
4736 ## Booting Linux kernel at 40100000 ...
4737 Image Name: 2.2.13 for initrd on TQM850L
4738 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4739 Data Size: 335725 Bytes = 327 kB = 0 MB
4740 Load Address: 00000000
4741 Entry Point: 0000000c
4742 Verifying Checksum ... OK
4743 Uncompressing Kernel Image ... OK
4744 ## Loading RAMDisk Image at 40200000 ...
4745 Image Name: Simple Ramdisk Image
4746 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4747 Data Size: 566530 Bytes = 553 kB = 0 MB
4748 Load Address: 00000000
4749 Entry Point: 00000000
4750 Verifying Checksum ... OK
4751 Loading Ramdisk ... OK
4752 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
4753 Boot arguments: root=/dev/ram
4754 time_init: decrementer frequency = 187500000/60
4755 Calibrating delay loop... 49.77 BogoMIPS
4757 RAMDISK: Compressed image found at block 0
4758 VFS: Mounted root (ext2 filesystem).
4762 Boot Linux and pass a flat device tree:
4765 First, U-Boot must be compiled with the appropriate defines. See the section
4766 titled "Linux Kernel Interface" above for a more in depth explanation. The
4767 following is an example of how to start a kernel and pass an updated
4773 oft=oftrees/mpc8540ads.dtb
4774 => tftp $oftaddr $oft
4775 Speed: 1000, full duplex
4777 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4778 Filename 'oftrees/mpc8540ads.dtb'.
4779 Load address: 0x300000
4782 Bytes transferred = 4106 (100a hex)
4783 => tftp $loadaddr $bootfile
4784 Speed: 1000, full duplex
4786 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4788 Load address: 0x200000
4789 Loading:############
4791 Bytes transferred = 1029407 (fb51f hex)
4796 => bootm $loadaddr - $oftaddr
4797 ## Booting image at 00200000 ...
4798 Image Name: Linux-2.6.17-dirty
4799 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4800 Data Size: 1029343 Bytes = 1005.2 kB
4801 Load Address: 00000000
4802 Entry Point: 00000000
4803 Verifying Checksum ... OK
4804 Uncompressing Kernel Image ... OK
4805 Booting using flat device tree at 0x300000
4806 Using MPC85xx ADS machine description
4807 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4811 More About U-Boot Image Types:
4812 ------------------------------
4814 U-Boot supports the following image types:
4816 "Standalone Programs" are directly runnable in the environment
4817 provided by U-Boot; it is expected that (if they behave
4818 well) you can continue to work in U-Boot after return from
4819 the Standalone Program.
4820 "OS Kernel Images" are usually images of some Embedded OS which
4821 will take over control completely. Usually these programs
4822 will install their own set of exception handlers, device
4823 drivers, set up the MMU, etc. - this means, that you cannot
4824 expect to re-enter U-Boot except by resetting the CPU.
4825 "RAMDisk Images" are more or less just data blocks, and their
4826 parameters (address, size) are passed to an OS kernel that is
4828 "Multi-File Images" contain several images, typically an OS
4829 (Linux) kernel image and one or more data images like
4830 RAMDisks. This construct is useful for instance when you want
4831 to boot over the network using BOOTP etc., where the boot
4832 server provides just a single image file, but you want to get
4833 for instance an OS kernel and a RAMDisk image.
4835 "Multi-File Images" start with a list of image sizes, each
4836 image size (in bytes) specified by an "uint32_t" in network
4837 byte order. This list is terminated by an "(uint32_t)0".
4838 Immediately after the terminating 0 follow the images, one by
4839 one, all aligned on "uint32_t" boundaries (size rounded up to
4840 a multiple of 4 bytes).
4842 "Firmware Images" are binary images containing firmware (like
4843 U-Boot or FPGA images) which usually will be programmed to
4846 "Script files" are command sequences that will be executed by
4847 U-Boot's command interpreter; this feature is especially
4848 useful when you configure U-Boot to use a real shell (hush)
4849 as command interpreter.
4851 Booting the Linux zImage:
4852 -------------------------
4854 On some platforms, it's possible to boot Linux zImage. This is done
4855 using the "bootz" command. The syntax of "bootz" command is the same
4856 as the syntax of "bootm" command.
4858 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4859 kernel with raw initrd images. The syntax is slightly different, the
4860 address of the initrd must be augmented by it's size, in the following
4861 format: "<initrd addres>:<initrd size>".
4867 One of the features of U-Boot is that you can dynamically load and
4868 run "standalone" applications, which can use some resources of
4869 U-Boot like console I/O functions or interrupt services.
4871 Two simple examples are included with the sources:
4876 'examples/hello_world.c' contains a small "Hello World" Demo
4877 application; it is automatically compiled when you build U-Boot.
4878 It's configured to run at address 0x00040004, so you can play with it
4882 ## Ready for S-Record download ...
4883 ~>examples/hello_world.srec
4884 1 2 3 4 5 6 7 8 9 10 11 ...
4885 [file transfer complete]
4887 ## Start Addr = 0x00040004
4889 => go 40004 Hello World! This is a test.
4890 ## Starting application at 0x00040004 ...
4901 Hit any key to exit ...
4903 ## Application terminated, rc = 0x0
4905 Another example, which demonstrates how to register a CPM interrupt
4906 handler with the U-Boot code, can be found in 'examples/timer.c'.
4907 Here, a CPM timer is set up to generate an interrupt every second.
4908 The interrupt service routine is trivial, just printing a '.'
4909 character, but this is just a demo program. The application can be
4910 controlled by the following keys:
4912 ? - print current values og the CPM Timer registers
4913 b - enable interrupts and start timer
4914 e - stop timer and disable interrupts
4915 q - quit application
4918 ## Ready for S-Record download ...
4919 ~>examples/timer.srec
4920 1 2 3 4 5 6 7 8 9 10 11 ...
4921 [file transfer complete]
4923 ## Start Addr = 0x00040004
4926 ## Starting application at 0x00040004 ...
4929 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4932 [q, b, e, ?] Set interval 1000000 us
4935 [q, b, e, ?] ........
4936 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4939 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4942 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4945 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4947 [q, b, e, ?] ...Stopping timer
4949 [q, b, e, ?] ## Application terminated, rc = 0x0
4955 Over time, many people have reported problems when trying to use the
4956 "minicom" terminal emulation program for serial download. I (wd)
4957 consider minicom to be broken, and recommend not to use it. Under
4958 Unix, I recommend to use C-Kermit for general purpose use (and
4959 especially for kermit binary protocol download ("loadb" command), and
4960 use "cu" for S-Record download ("loads" command). See
4961 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4962 for help with kermit.
4965 Nevertheless, if you absolutely want to use it try adding this
4966 configuration to your "File transfer protocols" section:
4968 Name Program Name U/D FullScr IO-Red. Multi
4969 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4970 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4976 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4977 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4979 Building requires a cross environment; it is known to work on
4980 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4981 need gmake since the Makefiles are not compatible with BSD make).
4982 Note that the cross-powerpc package does not install include files;
4983 attempting to build U-Boot will fail because <machine/ansi.h> is
4984 missing. This file has to be installed and patched manually:
4986 # cd /usr/pkg/cross/powerpc-netbsd/include
4988 # ln -s powerpc machine
4989 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4990 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4992 Native builds *don't* work due to incompatibilities between native
4993 and U-Boot include files.
4995 Booting assumes that (the first part of) the image booted is a
4996 stage-2 loader which in turn loads and then invokes the kernel
4997 proper. Loader sources will eventually appear in the NetBSD source
4998 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4999 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5002 Implementation Internals:
5003 =========================
5005 The following is not intended to be a complete description of every
5006 implementation detail. However, it should help to understand the
5007 inner workings of U-Boot and make it easier to port it to custom
5011 Initial Stack, Global Data:
5012 ---------------------------
5014 The implementation of U-Boot is complicated by the fact that U-Boot
5015 starts running out of ROM (flash memory), usually without access to
5016 system RAM (because the memory controller is not initialized yet).
5017 This means that we don't have writable Data or BSS segments, and BSS
5018 is not initialized as zero. To be able to get a C environment working
5019 at all, we have to allocate at least a minimal stack. Implementation
5020 options for this are defined and restricted by the CPU used: Some CPU
5021 models provide on-chip memory (like the IMMR area on MPC8xx and
5022 MPC826x processors), on others (parts of) the data cache can be
5023 locked as (mis-) used as memory, etc.
5025 Chris Hallinan posted a good summary of these issues to the
5026 U-Boot mailing list:
5028 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5029 From: "Chris Hallinan" <clh@net1plus.com>
5030 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5033 Correct me if I'm wrong, folks, but the way I understand it
5034 is this: Using DCACHE as initial RAM for Stack, etc, does not
5035 require any physical RAM backing up the cache. The cleverness
5036 is that the cache is being used as a temporary supply of
5037 necessary storage before the SDRAM controller is setup. It's
5038 beyond the scope of this list to explain the details, but you
5039 can see how this works by studying the cache architecture and
5040 operation in the architecture and processor-specific manuals.
5042 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5043 is another option for the system designer to use as an
5044 initial stack/RAM area prior to SDRAM being available. Either
5045 option should work for you. Using CS 4 should be fine if your
5046 board designers haven't used it for something that would
5047 cause you grief during the initial boot! It is frequently not
5050 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5051 with your processor/board/system design. The default value
5052 you will find in any recent u-boot distribution in
5053 walnut.h should work for you. I'd set it to a value larger
5054 than your SDRAM module. If you have a 64MB SDRAM module, set
5055 it above 400_0000. Just make sure your board has no resources
5056 that are supposed to respond to that address! That code in
5057 start.S has been around a while and should work as is when
5058 you get the config right.
5063 It is essential to remember this, since it has some impact on the C
5064 code for the initialization procedures:
5066 * Initialized global data (data segment) is read-only. Do not attempt
5069 * Do not use any uninitialized global data (or implicitely initialized
5070 as zero data - BSS segment) at all - this is undefined, initiali-
5071 zation is performed later (when relocating to RAM).
5073 * Stack space is very limited. Avoid big data buffers or things like
5076 Having only the stack as writable memory limits means we cannot use
5077 normal global data to share information beween the code. But it
5078 turned out that the implementation of U-Boot can be greatly
5079 simplified by making a global data structure (gd_t) available to all
5080 functions. We could pass a pointer to this data as argument to _all_
5081 functions, but this would bloat the code. Instead we use a feature of
5082 the GCC compiler (Global Register Variables) to share the data: we
5083 place a pointer (gd) to the global data into a register which we
5084 reserve for this purpose.
5086 When choosing a register for such a purpose we are restricted by the
5087 relevant (E)ABI specifications for the current architecture, and by
5088 GCC's implementation.
5090 For PowerPC, the following registers have specific use:
5092 R2: reserved for system use
5093 R3-R4: parameter passing and return values
5094 R5-R10: parameter passing
5095 R13: small data area pointer
5099 (U-Boot also uses R12 as internal GOT pointer. r12
5100 is a volatile register so r12 needs to be reset when
5101 going back and forth between asm and C)
5103 ==> U-Boot will use R2 to hold a pointer to the global data
5105 Note: on PPC, we could use a static initializer (since the
5106 address of the global data structure is known at compile time),
5107 but it turned out that reserving a register results in somewhat
5108 smaller code - although the code savings are not that big (on
5109 average for all boards 752 bytes for the whole U-Boot image,
5110 624 text + 127 data).
5112 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5113 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5115 ==> U-Boot will use P3 to hold a pointer to the global data
5117 On ARM, the following registers are used:
5119 R0: function argument word/integer result
5120 R1-R3: function argument word
5122 R10: stack limit (used only if stack checking if enabled)
5123 R11: argument (frame) pointer
5124 R12: temporary workspace
5127 R15: program counter
5129 ==> U-Boot will use R8 to hold a pointer to the global data
5131 On Nios II, the ABI is documented here:
5132 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5134 ==> U-Boot will use gp to hold a pointer to the global data
5136 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5137 to access small data sections, so gp is free.
5139 On NDS32, the following registers are used:
5141 R0-R1: argument/return
5143 R15: temporary register for assembler
5144 R16: trampoline register
5145 R28: frame pointer (FP)
5146 R29: global pointer (GP)
5147 R30: link register (LP)
5148 R31: stack pointer (SP)
5149 PC: program counter (PC)
5151 ==> U-Boot will use R10 to hold a pointer to the global data
5153 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5154 or current versions of GCC may "optimize" the code too much.
5159 U-Boot runs in system state and uses physical addresses, i.e. the
5160 MMU is not used either for address mapping nor for memory protection.
5162 The available memory is mapped to fixed addresses using the memory
5163 controller. In this process, a contiguous block is formed for each
5164 memory type (Flash, SDRAM, SRAM), even when it consists of several
5165 physical memory banks.
5167 U-Boot is installed in the first 128 kB of the first Flash bank (on
5168 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5169 booting and sizing and initializing DRAM, the code relocates itself
5170 to the upper end of DRAM. Immediately below the U-Boot code some
5171 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5172 configuration setting]. Below that, a structure with global Board
5173 Info data is placed, followed by the stack (growing downward).
5175 Additionally, some exception handler code is copied to the low 8 kB
5176 of DRAM (0x00000000 ... 0x00001FFF).
5178 So a typical memory configuration with 16 MB of DRAM could look like
5181 0x0000 0000 Exception Vector code
5184 0x0000 2000 Free for Application Use
5190 0x00FB FF20 Monitor Stack (Growing downward)
5191 0x00FB FFAC Board Info Data and permanent copy of global data
5192 0x00FC 0000 Malloc Arena
5195 0x00FE 0000 RAM Copy of Monitor Code
5196 ... eventually: LCD or video framebuffer
5197 ... eventually: pRAM (Protected RAM - unchanged by reset)
5198 0x00FF FFFF [End of RAM]
5201 System Initialization:
5202 ----------------------
5204 In the reset configuration, U-Boot starts at the reset entry point
5205 (on most PowerPC systems at address 0x00000100). Because of the reset
5206 configuration for CS0# this is a mirror of the onboard Flash memory.
5207 To be able to re-map memory U-Boot then jumps to its link address.
5208 To be able to implement the initialization code in C, a (small!)
5209 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5210 which provide such a feature like MPC8xx or MPC8260), or in a locked
5211 part of the data cache. After that, U-Boot initializes the CPU core,
5212 the caches and the SIU.
5214 Next, all (potentially) available memory banks are mapped using a
5215 preliminary mapping. For example, we put them on 512 MB boundaries
5216 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5217 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5218 programmed for SDRAM access. Using the temporary configuration, a
5219 simple memory test is run that determines the size of the SDRAM
5222 When there is more than one SDRAM bank, and the banks are of
5223 different size, the largest is mapped first. For equal size, the first
5224 bank (CS2#) is mapped first. The first mapping is always for address
5225 0x00000000, with any additional banks following immediately to create
5226 contiguous memory starting from 0.
5228 Then, the monitor installs itself at the upper end of the SDRAM area
5229 and allocates memory for use by malloc() and for the global Board
5230 Info data; also, the exception vector code is copied to the low RAM
5231 pages, and the final stack is set up.
5233 Only after this relocation will you have a "normal" C environment;
5234 until that you are restricted in several ways, mostly because you are
5235 running from ROM, and because the code will have to be relocated to a
5239 U-Boot Porting Guide:
5240 ----------------------
5242 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5246 int main(int argc, char *argv[])
5248 sighandler_t no_more_time;
5250 signal(SIGALRM, no_more_time);
5251 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5253 if (available_money > available_manpower) {
5254 Pay consultant to port U-Boot;
5258 Download latest U-Boot source;
5260 Subscribe to u-boot mailing list;
5263 email("Hi, I am new to U-Boot, how do I get started?");
5266 Read the README file in the top level directory;
5267 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5268 Read applicable doc/*.README;
5269 Read the source, Luke;
5270 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5273 if (available_money > toLocalCurrency ($2500))
5276 Add a lot of aggravation and time;
5278 if (a similar board exists) { /* hopefully... */
5279 cp -a board/<similar> board/<myboard>
5280 cp include/configs/<similar>.h include/configs/<myboard>.h
5282 Create your own board support subdirectory;
5283 Create your own board include/configs/<myboard>.h file;
5285 Edit new board/<myboard> files
5286 Edit new include/configs/<myboard>.h
5291 Add / modify source code;
5295 email("Hi, I am having problems...");
5297 Send patch file to the U-Boot email list;
5298 if (reasonable critiques)
5299 Incorporate improvements from email list code review;
5301 Defend code as written;
5307 void no_more_time (int sig)
5316 All contributions to U-Boot should conform to the Linux kernel
5317 coding style; see the file "Documentation/CodingStyle" and the script
5318 "scripts/Lindent" in your Linux kernel source directory.
5320 Source files originating from a different project (for example the
5321 MTD subsystem) are generally exempt from these guidelines and are not
5322 reformated to ease subsequent migration to newer versions of those
5325 Please note that U-Boot is implemented in C (and to some small parts in
5326 Assembler); no C++ is used, so please do not use C++ style comments (//)
5329 Please also stick to the following formatting rules:
5330 - remove any trailing white space
5331 - use TAB characters for indentation and vertical alignment, not spaces
5332 - make sure NOT to use DOS '\r\n' line feeds
5333 - do not add more than 2 consecutive empty lines to source files
5334 - do not add trailing empty lines to source files
5336 Submissions which do not conform to the standards may be returned
5337 with a request to reformat the changes.
5343 Since the number of patches for U-Boot is growing, we need to
5344 establish some rules. Submissions which do not conform to these rules
5345 may be rejected, even when they contain important and valuable stuff.
5347 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5349 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5350 see http://lists.denx.de/mailman/listinfo/u-boot
5352 When you send a patch, please include the following information with
5355 * For bug fixes: a description of the bug and how your patch fixes
5356 this bug. Please try to include a way of demonstrating that the
5357 patch actually fixes something.
5359 * For new features: a description of the feature and your
5362 * A CHANGELOG entry as plaintext (separate from the patch)
5364 * For major contributions, your entry to the CREDITS file
5366 * When you add support for a new board, don't forget to add this
5367 board to the MAINTAINERS file, too.
5369 * If your patch adds new configuration options, don't forget to
5370 document these in the README file.
5372 * The patch itself. If you are using git (which is *strongly*
5373 recommended) you can easily generate the patch using the
5374 "git format-patch". If you then use "git send-email" to send it to
5375 the U-Boot mailing list, you will avoid most of the common problems
5376 with some other mail clients.
5378 If you cannot use git, use "diff -purN OLD NEW". If your version of
5379 diff does not support these options, then get the latest version of
5382 The current directory when running this command shall be the parent
5383 directory of the U-Boot source tree (i. e. please make sure that
5384 your patch includes sufficient directory information for the
5387 We prefer patches as plain text. MIME attachments are discouraged,
5388 and compressed attachments must not be used.
5390 * If one logical set of modifications affects or creates several
5391 files, all these changes shall be submitted in a SINGLE patch file.
5393 * Changesets that contain different, unrelated modifications shall be
5394 submitted as SEPARATE patches, one patch per changeset.
5399 * Before sending the patch, run the MAKEALL script on your patched
5400 source tree and make sure that no errors or warnings are reported
5401 for any of the boards.
5403 * Keep your modifications to the necessary minimum: A patch
5404 containing several unrelated changes or arbitrary reformats will be
5405 returned with a request to re-formatting / split it.
5407 * If you modify existing code, make sure that your new code does not
5408 add to the memory footprint of the code ;-) Small is beautiful!
5409 When adding new features, these should compile conditionally only
5410 (using #ifdef), and the resulting code with the new feature
5411 disabled must not need more memory than the old code without your
5414 * Remember that there is a size limit of 100 kB per message on the
5415 u-boot mailing list. Bigger patches will be moderated. If they are
5416 reasonable and not too big, they will be acknowledged. But patches
5417 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob