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_EXPORTENV * export the environment
820 CONFIG_CMD_EXT2 * ext2 command support
821 CONFIG_CMD_EXT4 * ext4 command support
822 CONFIG_CMD_SAVEENV saveenv
823 CONFIG_CMD_FDC * Floppy Disk Support
824 CONFIG_CMD_FAT * FAT command support
825 CONFIG_CMD_FDOS * Dos diskette Support
826 CONFIG_CMD_FLASH flinfo, erase, protect
827 CONFIG_CMD_FPGA FPGA device initialization support
828 CONFIG_CMD_GETTIME * Get time since boot
829 CONFIG_CMD_GO * the 'go' command (exec code)
830 CONFIG_CMD_GREPENV * search environment
831 CONFIG_CMD_HASH * calculate hash / digest
832 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
833 CONFIG_CMD_I2C * I2C serial bus support
834 CONFIG_CMD_IDE * IDE harddisk support
835 CONFIG_CMD_IMI iminfo
836 CONFIG_CMD_IMLS List all found images
837 CONFIG_CMD_IMMAP * IMMR dump support
838 CONFIG_CMD_IMPORTENV * import an environment
839 CONFIG_CMD_INI * import data from an ini file into the env
840 CONFIG_CMD_IRQ * irqinfo
841 CONFIG_CMD_ITEST Integer/string test of 2 values
842 CONFIG_CMD_JFFS2 * JFFS2 Support
843 CONFIG_CMD_KGDB * kgdb
844 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
845 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
847 CONFIG_CMD_LOADB loadb
848 CONFIG_CMD_LOADS loads
849 CONFIG_CMD_MD5SUM print md5 message digest
850 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
851 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
853 CONFIG_CMD_MISC Misc functions like sleep etc
854 CONFIG_CMD_MMC * MMC memory mapped support
855 CONFIG_CMD_MII * MII utility commands
856 CONFIG_CMD_MTDPARTS * MTD partition support
857 CONFIG_CMD_NAND * NAND support
858 CONFIG_CMD_NET bootp, tftpboot, rarpboot
859 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
860 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
861 CONFIG_CMD_PCI * pciinfo
862 CONFIG_CMD_PCMCIA * PCMCIA support
863 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
865 CONFIG_CMD_PORTIO * Port I/O
866 CONFIG_CMD_READ * Read raw data from partition
867 CONFIG_CMD_REGINFO * Register dump
868 CONFIG_CMD_RUN run command in env variable
869 CONFIG_CMD_SAVES * save S record dump
870 CONFIG_CMD_SCSI * SCSI Support
871 CONFIG_CMD_SDRAM * print SDRAM configuration information
872 (requires CONFIG_CMD_I2C)
873 CONFIG_CMD_SETGETDCR Support for DCR Register access
875 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
876 CONFIG_CMD_SHA1SUM print sha1 memory digest
877 (requires CONFIG_CMD_MEMORY)
878 CONFIG_CMD_SOURCE "source" command Support
879 CONFIG_CMD_SPI * SPI serial bus support
880 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
881 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
882 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
883 CONFIG_CMD_TIMER * access to the system tick timer
884 CONFIG_CMD_USB * USB support
885 CONFIG_CMD_CDP * Cisco Discover Protocol support
886 CONFIG_CMD_MFSL * Microblaze FSL support
889 EXAMPLE: If you want all functions except of network
890 support you can write:
892 #include "config_cmd_all.h"
893 #undef CONFIG_CMD_NET
896 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
898 Note: Don't enable the "icache" and "dcache" commands
899 (configuration option CONFIG_CMD_CACHE) unless you know
900 what you (and your U-Boot users) are doing. Data
901 cache cannot be enabled on systems like the 8xx or
902 8260 (where accesses to the IMMR region must be
903 uncached), and it cannot be disabled on all other
904 systems where we (mis-) use the data cache to hold an
905 initial stack and some data.
908 XXX - this list needs to get updated!
912 If this variable is defined, U-Boot will use a device tree
913 to configure its devices, instead of relying on statically
914 compiled #defines in the board file. This option is
915 experimental and only available on a few boards. The device
916 tree is available in the global data as gd->fdt_blob.
918 U-Boot needs to get its device tree from somewhere. This can
919 be done using one of the two options below:
922 If this variable is defined, U-Boot will embed a device tree
923 binary in its image. This device tree file should be in the
924 board directory and called <soc>-<board>.dts. The binary file
925 is then picked up in board_init_f() and made available through
926 the global data structure as gd->blob.
929 If this variable is defined, U-Boot will build a device tree
930 binary. It will be called u-boot.dtb. Architecture-specific
931 code will locate it at run-time. Generally this works by:
933 cat u-boot.bin u-boot.dtb >image.bin
935 and in fact, U-Boot does this for you, creating a file called
936 u-boot-dtb.bin which is useful in the common case. You can
937 still use the individual files if you need something more
942 If this variable is defined, it enables watchdog
943 support for the SoC. There must be support in the SoC
944 specific code for a watchdog. For the 8xx and 8260
945 CPUs, the SIU Watchdog feature is enabled in the SYPCR
946 register. When supported for a specific SoC is
947 available, then no further board specific code should
951 When using a watchdog circuitry external to the used
952 SoC, then define this variable and provide board
953 specific code for the "hw_watchdog_reset" function.
956 CONFIG_VERSION_VARIABLE
957 If this variable is defined, an environment variable
958 named "ver" is created by U-Boot showing the U-Boot
959 version as printed by the "version" command.
960 Any change to this variable will be reverted at the
965 When CONFIG_CMD_DATE is selected, the type of the RTC
966 has to be selected, too. Define exactly one of the
969 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
970 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
971 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
972 CONFIG_RTC_MC146818 - use MC146818 RTC
973 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
974 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
975 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
976 CONFIG_RTC_DS164x - use Dallas DS164x RTC
977 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
978 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
979 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
980 CONFIG_SYS_RV3029_TCR - enable trickle charger on
983 Note that if the RTC uses I2C, then the I2C interface
984 must also be configured. See I2C Support, below.
987 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
988 CONFIG_PCA953X_INFO - enable pca953x info command
990 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
991 chip-ngpio pairs that tell the PCA953X driver the number of
992 pins supported by a particular chip.
994 Note that if the GPIO device uses I2C, then the I2C interface
995 must also be configured. See I2C Support, below.
999 When CONFIG_TIMESTAMP is selected, the timestamp
1000 (date and time) of an image is printed by image
1001 commands like bootm or iminfo. This option is
1002 automatically enabled when you select CONFIG_CMD_DATE .
1004 - Partition Labels (disklabels) Supported:
1005 Zero or more of the following:
1006 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1007 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1008 Intel architecture, USB sticks, etc.
1009 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1010 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1011 bootloader. Note 2TB partition limit; see
1013 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1015 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1016 CONFIG_CMD_SCSI) you must configure support for at
1017 least one non-MTD partition type as well.
1020 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1021 board configurations files but used nowhere!
1023 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1024 be performed by calling the function
1025 ide_set_reset(int reset)
1026 which has to be defined in a board specific file
1031 Set this to enable ATAPI support.
1036 Set this to enable support for disks larger than 137GB
1037 Also look at CONFIG_SYS_64BIT_LBA.
1038 Whithout these , LBA48 support uses 32bit variables and will 'only'
1039 support disks up to 2.1TB.
1041 CONFIG_SYS_64BIT_LBA:
1042 When enabled, makes the IDE subsystem use 64bit sector addresses.
1046 At the moment only there is only support for the
1047 SYM53C8XX SCSI controller; define
1048 CONFIG_SCSI_SYM53C8XX to enable it.
1050 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1051 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1052 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1053 maximum numbers of LUNs, SCSI ID's and target
1055 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1057 The environment variable 'scsidevs' is set to the number of
1058 SCSI devices found during the last scan.
1060 - NETWORK Support (PCI):
1062 Support for Intel 8254x/8257x gigabit chips.
1065 Utility code for direct access to the SPI bus on Intel 8257x.
1066 This does not do anything useful unless you set at least one
1067 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1069 CONFIG_E1000_SPI_GENERIC
1070 Allow generic access to the SPI bus on the Intel 8257x, for
1071 example with the "sspi" command.
1074 Management command for E1000 devices. When used on devices
1075 with SPI support you can reprogram the EEPROM from U-Boot.
1077 CONFIG_E1000_FALLBACK_MAC
1078 default MAC for empty EEPROM after production.
1081 Support for Intel 82557/82559/82559ER chips.
1082 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1083 write routine for first time initialisation.
1086 Support for Digital 2114x chips.
1087 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1088 modem chip initialisation (KS8761/QS6611).
1091 Support for National dp83815 chips.
1094 Support for National dp8382[01] gigabit chips.
1096 - NETWORK Support (other):
1098 CONFIG_DRIVER_AT91EMAC
1099 Support for AT91RM9200 EMAC.
1102 Define this to use reduced MII inteface
1104 CONFIG_DRIVER_AT91EMAC_QUIET
1105 If this defined, the driver is quiet.
1106 The driver doen't show link status messages.
1108 CONFIG_CALXEDA_XGMAC
1109 Support for the Calxeda XGMAC device
1112 Support for SMSC's LAN91C96 chips.
1114 CONFIG_LAN91C96_BASE
1115 Define this to hold the physical address
1116 of the LAN91C96's I/O space
1118 CONFIG_LAN91C96_USE_32_BIT
1119 Define this to enable 32 bit addressing
1122 Support for SMSC's LAN91C111 chip
1124 CONFIG_SMC91111_BASE
1125 Define this to hold the physical address
1126 of the device (I/O space)
1128 CONFIG_SMC_USE_32_BIT
1129 Define this if data bus is 32 bits
1131 CONFIG_SMC_USE_IOFUNCS
1132 Define this to use i/o functions instead of macros
1133 (some hardware wont work with macros)
1135 CONFIG_DRIVER_TI_EMAC
1136 Support for davinci emac
1138 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1139 Define this if you have more then 3 PHYs.
1142 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1144 CONFIG_FTGMAC100_EGIGA
1145 Define this to use GE link update with gigabit PHY.
1146 Define this if FTGMAC100 is connected to gigabit PHY.
1147 If your system has 10/100 PHY only, it might not occur
1148 wrong behavior. Because PHY usually return timeout or
1149 useless data when polling gigabit status and gigabit
1150 control registers. This behavior won't affect the
1151 correctnessof 10/100 link speed update.
1154 Support for SMSC's LAN911x and LAN921x chips
1157 Define this to hold the physical address
1158 of the device (I/O space)
1160 CONFIG_SMC911X_32_BIT
1161 Define this if data bus is 32 bits
1163 CONFIG_SMC911X_16_BIT
1164 Define this if data bus is 16 bits. If your processor
1165 automatically converts one 32 bit word to two 16 bit
1166 words you may also try CONFIG_SMC911X_32_BIT.
1169 Support for Renesas on-chip Ethernet controller
1171 CONFIG_SH_ETHER_USE_PORT
1172 Define the number of ports to be used
1174 CONFIG_SH_ETHER_PHY_ADDR
1175 Define the ETH PHY's address
1177 CONFIG_SH_ETHER_CACHE_WRITEBACK
1178 If this option is set, the driver enables cache flush.
1181 CONFIG_GENERIC_LPC_TPM
1182 Support for generic parallel port TPM devices. Only one device
1183 per system is supported at this time.
1185 CONFIG_TPM_TIS_BASE_ADDRESS
1186 Base address where the generic TPM device is mapped
1187 to. Contemporary x86 systems usually map it at
1191 At the moment only the UHCI host controller is
1192 supported (PIP405, MIP405, MPC5200); define
1193 CONFIG_USB_UHCI to enable it.
1194 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1195 and define CONFIG_USB_STORAGE to enable the USB
1198 Supported are USB Keyboards and USB Floppy drives
1200 MPC5200 USB requires additional defines:
1202 for 528 MHz Clock: 0x0001bbbb
1206 for differential drivers: 0x00001000
1207 for single ended drivers: 0x00005000
1208 for differential drivers on PSC3: 0x00000100
1209 for single ended drivers on PSC3: 0x00004100
1210 CONFIG_SYS_USB_EVENT_POLL
1211 May be defined to allow interrupt polling
1212 instead of using asynchronous interrupts
1214 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1215 txfilltuning field in the EHCI controller on reset.
1218 Define the below if you wish to use the USB console.
1219 Once firmware is rebuilt from a serial console issue the
1220 command "setenv stdin usbtty; setenv stdout usbtty" and
1221 attach your USB cable. The Unix command "dmesg" should print
1222 it has found a new device. The environment variable usbtty
1223 can be set to gserial or cdc_acm to enable your device to
1224 appear to a USB host as a Linux gserial device or a
1225 Common Device Class Abstract Control Model serial device.
1226 If you select usbtty = gserial you should be able to enumerate
1228 # modprobe usbserial vendor=0xVendorID product=0xProductID
1229 else if using cdc_acm, simply setting the environment
1230 variable usbtty to be cdc_acm should suffice. The following
1231 might be defined in YourBoardName.h
1234 Define this to build a UDC device
1237 Define this to have a tty type of device available to
1238 talk to the UDC device
1241 Define this to enable the high speed support for usb
1242 device and usbtty. If this feature is enabled, a routine
1243 int is_usbd_high_speed(void)
1244 also needs to be defined by the driver to dynamically poll
1245 whether the enumeration has succeded at high speed or full
1248 CONFIG_SYS_CONSOLE_IS_IN_ENV
1249 Define this if you want stdin, stdout &/or stderr to
1253 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1254 Derive USB clock from external clock "blah"
1255 - CONFIG_SYS_USB_EXTC_CLK 0x02
1257 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1258 Derive USB clock from brgclk
1259 - CONFIG_SYS_USB_BRG_CLK 0x04
1261 If you have a USB-IF assigned VendorID then you may wish to
1262 define your own vendor specific values either in BoardName.h
1263 or directly in usbd_vendor_info.h. If you don't define
1264 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1265 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1266 should pretend to be a Linux device to it's target host.
1268 CONFIG_USBD_MANUFACTURER
1269 Define this string as the name of your company for
1270 - CONFIG_USBD_MANUFACTURER "my company"
1272 CONFIG_USBD_PRODUCT_NAME
1273 Define this string as the name of your product
1274 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1276 CONFIG_USBD_VENDORID
1277 Define this as your assigned Vendor ID from the USB
1278 Implementors Forum. This *must* be a genuine Vendor ID
1279 to avoid polluting the USB namespace.
1280 - CONFIG_USBD_VENDORID 0xFFFF
1282 CONFIG_USBD_PRODUCTID
1283 Define this as the unique Product ID
1285 - CONFIG_USBD_PRODUCTID 0xFFFF
1287 - ULPI Layer Support:
1288 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1289 the generic ULPI layer. The generic layer accesses the ULPI PHY
1290 via the platform viewport, so you need both the genric layer and
1291 the viewport enabled. Currently only Chipidea/ARC based
1292 viewport is supported.
1293 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1294 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1295 If your ULPI phy needs a different reference clock than the
1296 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1297 the appropriate value in Hz.
1300 The MMC controller on the Intel PXA is supported. To
1301 enable this define CONFIG_MMC. The MMC can be
1302 accessed from the boot prompt by mapping the device
1303 to physical memory similar to flash. Command line is
1304 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1305 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1308 Support for Renesas on-chip MMCIF controller
1310 CONFIG_SH_MMCIF_ADDR
1311 Define the base address of MMCIF registers
1314 Define the clock frequency for MMCIF
1316 - Journaling Flash filesystem support:
1317 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1318 CONFIG_JFFS2_NAND_DEV
1319 Define these for a default partition on a NAND device
1321 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1322 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1323 Define these for a default partition on a NOR device
1325 CONFIG_SYS_JFFS_CUSTOM_PART
1326 Define this to create an own partition. You have to provide a
1327 function struct part_info* jffs2_part_info(int part_num)
1329 If you define only one JFFS2 partition you may also want to
1330 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1331 to disable the command chpart. This is the default when you
1332 have not defined a custom partition
1334 - FAT(File Allocation Table) filesystem write function support:
1337 Define this to enable support for saving memory data as a
1338 file in FAT formatted partition.
1340 This will also enable the command "fatwrite" enabling the
1341 user to write files to FAT.
1343 CBFS (Coreboot Filesystem) support
1346 Define this to enable support for reading from a Coreboot
1347 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1353 Define this to enable standard (PC-Style) keyboard
1357 Standard PC keyboard driver with US (is default) and
1358 GERMAN key layout (switch via environment 'keymap=de') support.
1359 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1360 for cfb_console. Supports cursor blinking.
1365 Define this to enable video support (for output to
1368 CONFIG_VIDEO_CT69000
1370 Enable Chips & Technologies 69000 Video chip
1372 CONFIG_VIDEO_SMI_LYNXEM
1373 Enable Silicon Motion SMI 712/710/810 Video chip. The
1374 video output is selected via environment 'videoout'
1375 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1378 For the CT69000 and SMI_LYNXEM drivers, videomode is
1379 selected via environment 'videomode'. Two different ways
1381 - "videomode=num" 'num' is a standard LiLo mode numbers.
1382 Following standard modes are supported (* is default):
1384 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1385 -------------+---------------------------------------------
1386 8 bits | 0x301* 0x303 0x305 0x161 0x307
1387 15 bits | 0x310 0x313 0x316 0x162 0x319
1388 16 bits | 0x311 0x314 0x317 0x163 0x31A
1389 24 bits | 0x312 0x315 0x318 ? 0x31B
1390 -------------+---------------------------------------------
1391 (i.e. setenv videomode 317; saveenv; reset;)
1393 - "videomode=bootargs" all the video parameters are parsed
1394 from the bootargs. (See drivers/video/videomodes.c)
1397 CONFIG_VIDEO_SED13806
1398 Enable Epson SED13806 driver. This driver supports 8bpp
1399 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1400 or CONFIG_VIDEO_SED13806_16BPP
1403 Enable the Freescale DIU video driver. Reference boards for
1404 SOCs that have a DIU should define this macro to enable DIU
1405 support, and should also define these other macros:
1411 CONFIG_VIDEO_SW_CURSOR
1412 CONFIG_VGA_AS_SINGLE_DEVICE
1414 CONFIG_VIDEO_BMP_LOGO
1416 The DIU driver will look for the 'video-mode' environment
1417 variable, and if defined, enable the DIU as a console during
1418 boot. See the documentation file README.video for a
1419 description of this variable.
1423 Enable the VGA video / BIOS for x86. The alternative if you
1424 are using coreboot is to use the coreboot frame buffer
1431 Define this to enable a custom keyboard support.
1432 This simply calls drv_keyboard_init() which must be
1433 defined in your board-specific files.
1434 The only board using this so far is RBC823.
1436 - LCD Support: CONFIG_LCD
1438 Define this to enable LCD support (for output to LCD
1439 display); also select one of the supported displays
1440 by defining one of these:
1444 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1446 CONFIG_NEC_NL6448AC33:
1448 NEC NL6448AC33-18. Active, color, single scan.
1450 CONFIG_NEC_NL6448BC20
1452 NEC NL6448BC20-08. 6.5", 640x480.
1453 Active, color, single scan.
1455 CONFIG_NEC_NL6448BC33_54
1457 NEC NL6448BC33-54. 10.4", 640x480.
1458 Active, color, single scan.
1462 Sharp 320x240. Active, color, single scan.
1463 It isn't 16x9, and I am not sure what it is.
1465 CONFIG_SHARP_LQ64D341
1467 Sharp LQ64D341 display, 640x480.
1468 Active, color, single scan.
1472 HLD1045 display, 640x480.
1473 Active, color, single scan.
1477 Optrex CBL50840-2 NF-FW 99 22 M5
1479 Hitachi LMG6912RPFC-00T
1483 320x240. Black & white.
1485 Normally display is black on white background; define
1486 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1490 Support drawing of RLE8-compressed bitmaps on the LCD.
1494 Enables an 'i2c edid' command which can read EDID
1495 information over I2C from an attached LCD display.
1498 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1500 If this option is set, the environment is checked for
1501 a variable "splashimage". If found, the usual display
1502 of logo, copyright and system information on the LCD
1503 is suppressed and the BMP image at the address
1504 specified in "splashimage" is loaded instead. The
1505 console is redirected to the "nulldev", too. This
1506 allows for a "silent" boot where a splash screen is
1507 loaded very quickly after power-on.
1509 CONFIG_SPLASH_SCREEN_ALIGN
1511 If this option is set the splash image can be freely positioned
1512 on the screen. Environment variable "splashpos" specifies the
1513 position as "x,y". If a positive number is given it is used as
1514 number of pixel from left/top. If a negative number is given it
1515 is used as number of pixel from right/bottom. You can also
1516 specify 'm' for centering the image.
1519 setenv splashpos m,m
1520 => image at center of screen
1522 setenv splashpos 30,20
1523 => image at x = 30 and y = 20
1525 setenv splashpos -10,m
1526 => vertically centered image
1527 at x = dspWidth - bmpWidth - 9
1529 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1531 If this option is set, additionally to standard BMP
1532 images, gzipped BMP images can be displayed via the
1533 splashscreen support or the bmp command.
1535 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1537 If this option is set, 8-bit RLE compressed BMP images
1538 can be displayed via the splashscreen support or the
1541 - Do compresssing for memory range:
1544 If this option is set, it would use zlib deflate method
1545 to compress the specified memory at its best effort.
1547 - Compression support:
1550 If this option is set, support for bzip2 compressed
1551 images is included. If not, only uncompressed and gzip
1552 compressed images are supported.
1554 NOTE: the bzip2 algorithm requires a lot of RAM, so
1555 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1560 If this option is set, support for lzma compressed
1563 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1564 requires an amount of dynamic memory that is given by the
1567 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1569 Where lc and lp stand for, respectively, Literal context bits
1570 and Literal pos bits.
1572 This value is upper-bounded by 14MB in the worst case. Anyway,
1573 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1574 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1575 a very small buffer.
1577 Use the lzmainfo tool to determinate the lc and lp values and
1578 then calculate the amount of needed dynamic memory (ensuring
1579 the appropriate CONFIG_SYS_MALLOC_LEN value).
1584 The address of PHY on MII bus.
1586 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1588 The clock frequency of the MII bus
1592 If this option is set, support for speed/duplex
1593 detection of gigabit PHY is included.
1595 CONFIG_PHY_RESET_DELAY
1597 Some PHY like Intel LXT971A need extra delay after
1598 reset before any MII register access is possible.
1599 For such PHY, set this option to the usec delay
1600 required. (minimum 300usec for LXT971A)
1602 CONFIG_PHY_CMD_DELAY (ppc4xx)
1604 Some PHY like Intel LXT971A need extra delay after
1605 command issued before MII status register can be read
1615 Define a default value for Ethernet address to use
1616 for the respective Ethernet interface, in case this
1617 is not determined automatically.
1622 Define a default value for the IP address to use for
1623 the default Ethernet interface, in case this is not
1624 determined through e.g. bootp.
1625 (Environment variable "ipaddr")
1627 - Server IP address:
1630 Defines a default value for the IP address of a TFTP
1631 server to contact when using the "tftboot" command.
1632 (Environment variable "serverip")
1634 CONFIG_KEEP_SERVERADDR
1636 Keeps the server's MAC address, in the env 'serveraddr'
1637 for passing to bootargs (like Linux's netconsole option)
1639 - Gateway IP address:
1642 Defines a default value for the IP address of the
1643 default router where packets to other networks are
1645 (Environment variable "gatewayip")
1650 Defines a default value for the subnet mask (or
1651 routing prefix) which is used to determine if an IP
1652 address belongs to the local subnet or needs to be
1653 forwarded through a router.
1654 (Environment variable "netmask")
1656 - Multicast TFTP Mode:
1659 Defines whether you want to support multicast TFTP as per
1660 rfc-2090; for example to work with atftp. Lets lots of targets
1661 tftp down the same boot image concurrently. Note: the Ethernet
1662 driver in use must provide a function: mcast() to join/leave a
1665 - BOOTP Recovery Mode:
1666 CONFIG_BOOTP_RANDOM_DELAY
1668 If you have many targets in a network that try to
1669 boot using BOOTP, you may want to avoid that all
1670 systems send out BOOTP requests at precisely the same
1671 moment (which would happen for instance at recovery
1672 from a power failure, when all systems will try to
1673 boot, thus flooding the BOOTP server. Defining
1674 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1675 inserted before sending out BOOTP requests. The
1676 following delays are inserted then:
1678 1st BOOTP request: delay 0 ... 1 sec
1679 2nd BOOTP request: delay 0 ... 2 sec
1680 3rd BOOTP request: delay 0 ... 4 sec
1682 BOOTP requests: delay 0 ... 8 sec
1684 - DHCP Advanced Options:
1685 You can fine tune the DHCP functionality by defining
1686 CONFIG_BOOTP_* symbols:
1688 CONFIG_BOOTP_SUBNETMASK
1689 CONFIG_BOOTP_GATEWAY
1690 CONFIG_BOOTP_HOSTNAME
1691 CONFIG_BOOTP_NISDOMAIN
1692 CONFIG_BOOTP_BOOTPATH
1693 CONFIG_BOOTP_BOOTFILESIZE
1696 CONFIG_BOOTP_SEND_HOSTNAME
1697 CONFIG_BOOTP_NTPSERVER
1698 CONFIG_BOOTP_TIMEOFFSET
1699 CONFIG_BOOTP_VENDOREX
1700 CONFIG_BOOTP_MAY_FAIL
1702 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1703 environment variable, not the BOOTP server.
1705 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1706 after the configured retry count, the call will fail
1707 instead of starting over. This can be used to fail over
1708 to Link-local IP address configuration if the DHCP server
1711 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1712 serverip from a DHCP server, it is possible that more
1713 than one DNS serverip is offered to the client.
1714 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1715 serverip will be stored in the additional environment
1716 variable "dnsip2". The first DNS serverip is always
1717 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1720 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1721 to do a dynamic update of a DNS server. To do this, they
1722 need the hostname of the DHCP requester.
1723 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1724 of the "hostname" environment variable is passed as
1725 option 12 to the DHCP server.
1727 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1729 A 32bit value in microseconds for a delay between
1730 receiving a "DHCP Offer" and sending the "DHCP Request".
1731 This fixes a problem with certain DHCP servers that don't
1732 respond 100% of the time to a "DHCP request". E.g. On an
1733 AT91RM9200 processor running at 180MHz, this delay needed
1734 to be *at least* 15,000 usec before a Windows Server 2003
1735 DHCP server would reply 100% of the time. I recommend at
1736 least 50,000 usec to be safe. The alternative is to hope
1737 that one of the retries will be successful but note that
1738 the DHCP timeout and retry process takes a longer than
1741 - Link-local IP address negotiation:
1742 Negotiate with other link-local clients on the local network
1743 for an address that doesn't require explicit configuration.
1744 This is especially useful if a DHCP server cannot be guaranteed
1745 to exist in all environments that the device must operate.
1747 See doc/README.link-local for more information.
1750 CONFIG_CDP_DEVICE_ID
1752 The device id used in CDP trigger frames.
1754 CONFIG_CDP_DEVICE_ID_PREFIX
1756 A two character string which is prefixed to the MAC address
1761 A printf format string which contains the ascii name of
1762 the port. Normally is set to "eth%d" which sets
1763 eth0 for the first Ethernet, eth1 for the second etc.
1765 CONFIG_CDP_CAPABILITIES
1767 A 32bit integer which indicates the device capabilities;
1768 0x00000010 for a normal host which does not forwards.
1772 An ascii string containing the version of the software.
1776 An ascii string containing the name of the platform.
1780 A 32bit integer sent on the trigger.
1782 CONFIG_CDP_POWER_CONSUMPTION
1784 A 16bit integer containing the power consumption of the
1785 device in .1 of milliwatts.
1787 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1789 A byte containing the id of the VLAN.
1791 - Status LED: CONFIG_STATUS_LED
1793 Several configurations allow to display the current
1794 status using a LED. For instance, the LED will blink
1795 fast while running U-Boot code, stop blinking as
1796 soon as a reply to a BOOTP request was received, and
1797 start blinking slow once the Linux kernel is running
1798 (supported by a status LED driver in the Linux
1799 kernel). Defining CONFIG_STATUS_LED enables this
1802 - CAN Support: CONFIG_CAN_DRIVER
1804 Defining CONFIG_CAN_DRIVER enables CAN driver support
1805 on those systems that support this (optional)
1806 feature, like the TQM8xxL modules.
1808 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1810 These enable I2C serial bus commands. Defining either of
1811 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1812 include the appropriate I2C driver for the selected CPU.
1814 This will allow you to use i2c commands at the u-boot
1815 command line (as long as you set CONFIG_CMD_I2C in
1816 CONFIG_COMMANDS) and communicate with i2c based realtime
1817 clock chips. See common/cmd_i2c.c for a description of the
1818 command line interface.
1820 CONFIG_HARD_I2C selects a hardware I2C controller.
1822 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1823 bit-banging) driver instead of CPM or similar hardware
1826 There are several other quantities that must also be
1827 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1829 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1830 to be the frequency (in Hz) at which you wish your i2c bus
1831 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1832 the CPU's i2c node address).
1834 Now, the u-boot i2c code for the mpc8xx
1835 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1836 and so its address should therefore be cleared to 0 (See,
1837 eg, MPC823e User's Manual p.16-473). So, set
1838 CONFIG_SYS_I2C_SLAVE to 0.
1840 CONFIG_SYS_I2C_INIT_MPC5XXX
1842 When a board is reset during an i2c bus transfer
1843 chips might think that the current transfer is still
1844 in progress. Reset the slave devices by sending start
1845 commands until the slave device responds.
1847 That's all that's required for CONFIG_HARD_I2C.
1849 If you use the software i2c interface (CONFIG_SOFT_I2C)
1850 then the following macros need to be defined (examples are
1851 from include/configs/lwmon.h):
1855 (Optional). Any commands necessary to enable the I2C
1856 controller or configure ports.
1858 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1862 (Only for MPC8260 CPU). The I/O port to use (the code
1863 assumes both bits are on the same port). Valid values
1864 are 0..3 for ports A..D.
1868 The code necessary to make the I2C data line active
1869 (driven). If the data line is open collector, this
1872 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1876 The code necessary to make the I2C data line tri-stated
1877 (inactive). If the data line is open collector, this
1880 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1884 Code that returns TRUE if the I2C data line is high,
1887 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1891 If <bit> is TRUE, sets the I2C data line high. If it
1892 is FALSE, it clears it (low).
1894 eg: #define I2C_SDA(bit) \
1895 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1896 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1900 If <bit> is TRUE, sets the I2C clock line high. If it
1901 is FALSE, it clears it (low).
1903 eg: #define I2C_SCL(bit) \
1904 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1905 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1909 This delay is invoked four times per clock cycle so this
1910 controls the rate of data transfer. The data rate thus
1911 is 1 / (I2C_DELAY * 4). Often defined to be something
1914 #define I2C_DELAY udelay(2)
1916 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1918 If your arch supports the generic GPIO framework (asm/gpio.h),
1919 then you may alternatively define the two GPIOs that are to be
1920 used as SCL / SDA. Any of the previous I2C_xxx macros will
1921 have GPIO-based defaults assigned to them as appropriate.
1923 You should define these to the GPIO value as given directly to
1924 the generic GPIO functions.
1926 CONFIG_SYS_I2C_INIT_BOARD
1928 When a board is reset during an i2c bus transfer
1929 chips might think that the current transfer is still
1930 in progress. On some boards it is possible to access
1931 the i2c SCLK line directly, either by using the
1932 processor pin as a GPIO or by having a second pin
1933 connected to the bus. If this option is defined a
1934 custom i2c_init_board() routine in boards/xxx/board.c
1935 is run early in the boot sequence.
1937 CONFIG_SYS_I2C_BOARD_LATE_INIT
1939 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1940 defined a custom i2c_board_late_init() routine in
1941 boards/xxx/board.c is run AFTER the operations in i2c_init()
1942 is completed. This callpoint can be used to unreset i2c bus
1943 using CPU i2c controller register accesses for CPUs whose i2c
1944 controller provide such a method. It is called at the end of
1945 i2c_init() to allow i2c_init operations to setup the i2c bus
1946 controller on the CPU (e.g. setting bus speed & slave address).
1948 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1950 This option enables configuration of bi_iic_fast[] flags
1951 in u-boot bd_info structure based on u-boot environment
1952 variable "i2cfast". (see also i2cfast)
1954 CONFIG_I2C_MULTI_BUS
1956 This option allows the use of multiple I2C buses, each of which
1957 must have a controller. At any point in time, only one bus is
1958 active. To switch to a different bus, use the 'i2c dev' command.
1959 Note that bus numbering is zero-based.
1961 CONFIG_SYS_I2C_NOPROBES
1963 This option specifies a list of I2C devices that will be skipped
1964 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1965 is set, specify a list of bus-device pairs. Otherwise, specify
1966 a 1D array of device addresses
1969 #undef CONFIG_I2C_MULTI_BUS
1970 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1972 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1974 #define CONFIG_I2C_MULTI_BUS
1975 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1977 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1979 CONFIG_SYS_SPD_BUS_NUM
1981 If defined, then this indicates the I2C bus number for DDR SPD.
1982 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1984 CONFIG_SYS_RTC_BUS_NUM
1986 If defined, then this indicates the I2C bus number for the RTC.
1987 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1989 CONFIG_SYS_DTT_BUS_NUM
1991 If defined, then this indicates the I2C bus number for the DTT.
1992 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1994 CONFIG_SYS_I2C_DTT_ADDR:
1996 If defined, specifies the I2C address of the DTT device.
1997 If not defined, then U-Boot uses predefined value for
1998 specified DTT device.
2002 Define this option if you want to use Freescale's I2C driver in
2003 drivers/i2c/fsl_i2c.c.
2007 Define this option if you have I2C devices reached over 1 .. n
2008 I2C Muxes like the pca9544a. This option addes a new I2C
2009 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2010 new I2C Bus to the existing I2C Busses. If you select the
2011 new Bus with "i2c dev", u-bbot sends first the commandos for
2012 the muxes to activate this new "bus".
2014 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2018 Adding a new I2C Bus reached over 2 pca9544a muxes
2019 The First mux with address 70 and channel 6
2020 The Second mux with address 71 and channel 4
2022 => i2c bus pca9544a:70:6:pca9544a:71:4
2024 Use the "i2c bus" command without parameter, to get a list
2025 of I2C Busses with muxes:
2028 Busses reached over muxes:
2030 reached over Mux(es):
2033 reached over Mux(es):
2038 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2039 u-boot first sends the command to the mux@70 to enable
2040 channel 6, and then the command to the mux@71 to enable
2043 After that, you can use the "normal" i2c commands as
2044 usual to communicate with your I2C devices behind
2047 This option is actually implemented for the bitbanging
2048 algorithm in common/soft_i2c.c and for the Hardware I2C
2049 Bus on the MPC8260. But it should be not so difficult
2050 to add this option to other architectures.
2052 CONFIG_SOFT_I2C_READ_REPEATED_START
2054 defining this will force the i2c_read() function in
2055 the soft_i2c driver to perform an I2C repeated start
2056 between writing the address pointer and reading the
2057 data. If this define is omitted the default behaviour
2058 of doing a stop-start sequence will be used. Most I2C
2059 devices can use either method, but some require one or
2062 - SPI Support: CONFIG_SPI
2064 Enables SPI driver (so far only tested with
2065 SPI EEPROM, also an instance works with Crystal A/D and
2066 D/As on the SACSng board)
2070 Enables the driver for SPI controller on SuperH. Currently
2071 only SH7757 is supported.
2075 Enables extended (16-bit) SPI EEPROM addressing.
2076 (symmetrical to CONFIG_I2C_X)
2080 Enables a software (bit-bang) SPI driver rather than
2081 using hardware support. This is a general purpose
2082 driver that only requires three general I/O port pins
2083 (two outputs, one input) to function. If this is
2084 defined, the board configuration must define several
2085 SPI configuration items (port pins to use, etc). For
2086 an example, see include/configs/sacsng.h.
2090 Enables a hardware SPI driver for general-purpose reads
2091 and writes. As with CONFIG_SOFT_SPI, the board configuration
2092 must define a list of chip-select function pointers.
2093 Currently supported on some MPC8xxx processors. For an
2094 example, see include/configs/mpc8349emds.h.
2098 Enables the driver for the SPI controllers on i.MX and MXC
2099 SoCs. Currently i.MX31/35/51 are supported.
2101 - FPGA Support: CONFIG_FPGA
2103 Enables FPGA subsystem.
2105 CONFIG_FPGA_<vendor>
2107 Enables support for specific chip vendors.
2110 CONFIG_FPGA_<family>
2112 Enables support for FPGA family.
2113 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2117 Specify the number of FPGA devices to support.
2119 CONFIG_SYS_FPGA_PROG_FEEDBACK
2121 Enable printing of hash marks during FPGA configuration.
2123 CONFIG_SYS_FPGA_CHECK_BUSY
2125 Enable checks on FPGA configuration interface busy
2126 status by the configuration function. This option
2127 will require a board or device specific function to
2132 If defined, a function that provides delays in the FPGA
2133 configuration driver.
2135 CONFIG_SYS_FPGA_CHECK_CTRLC
2136 Allow Control-C to interrupt FPGA configuration
2138 CONFIG_SYS_FPGA_CHECK_ERROR
2140 Check for configuration errors during FPGA bitfile
2141 loading. For example, abort during Virtex II
2142 configuration if the INIT_B line goes low (which
2143 indicated a CRC error).
2145 CONFIG_SYS_FPGA_WAIT_INIT
2147 Maximum time to wait for the INIT_B line to deassert
2148 after PROB_B has been deasserted during a Virtex II
2149 FPGA configuration sequence. The default time is 500
2152 CONFIG_SYS_FPGA_WAIT_BUSY
2154 Maximum time to wait for BUSY to deassert during
2155 Virtex II FPGA configuration. The default is 5 ms.
2157 CONFIG_SYS_FPGA_WAIT_CONFIG
2159 Time to wait after FPGA configuration. The default is
2162 - Configuration Management:
2165 If defined, this string will be added to the U-Boot
2166 version information (U_BOOT_VERSION)
2168 - Vendor Parameter Protection:
2170 U-Boot considers the values of the environment
2171 variables "serial#" (Board Serial Number) and
2172 "ethaddr" (Ethernet Address) to be parameters that
2173 are set once by the board vendor / manufacturer, and
2174 protects these variables from casual modification by
2175 the user. Once set, these variables are read-only,
2176 and write or delete attempts are rejected. You can
2177 change this behaviour:
2179 If CONFIG_ENV_OVERWRITE is #defined in your config
2180 file, the write protection for vendor parameters is
2181 completely disabled. Anybody can change or delete
2184 Alternatively, if you #define _both_ CONFIG_ETHADDR
2185 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2186 Ethernet address is installed in the environment,
2187 which can be changed exactly ONCE by the user. [The
2188 serial# is unaffected by this, i. e. it remains
2191 The same can be accomplished in a more flexible way
2192 for any variable by configuring the type of access
2193 to allow for those variables in the ".flags" variable
2194 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2199 Define this variable to enable the reservation of
2200 "protected RAM", i. e. RAM which is not overwritten
2201 by U-Boot. Define CONFIG_PRAM to hold the number of
2202 kB you want to reserve for pRAM. You can overwrite
2203 this default value by defining an environment
2204 variable "pram" to the number of kB you want to
2205 reserve. Note that the board info structure will
2206 still show the full amount of RAM. If pRAM is
2207 reserved, a new environment variable "mem" will
2208 automatically be defined to hold the amount of
2209 remaining RAM in a form that can be passed as boot
2210 argument to Linux, for instance like that:
2212 setenv bootargs ... mem=\${mem}
2215 This way you can tell Linux not to use this memory,
2216 either, which results in a memory region that will
2217 not be affected by reboots.
2219 *WARNING* If your board configuration uses automatic
2220 detection of the RAM size, you must make sure that
2221 this memory test is non-destructive. So far, the
2222 following board configurations are known to be
2225 IVMS8, IVML24, SPD8xx, TQM8xxL,
2226 HERMES, IP860, RPXlite, LWMON,
2229 - Access to physical memory region (> 4GB)
2230 Some basic support is provided for operations on memory not
2231 normally accessible to U-Boot - e.g. some architectures
2232 support access to more than 4GB of memory on 32-bit
2233 machines using physical address extension or similar.
2234 Define CONFIG_PHYSMEM to access this basic support, which
2235 currently only supports clearing the memory.
2240 Define this variable to stop the system in case of a
2241 fatal error, so that you have to reset it manually.
2242 This is probably NOT a good idea for an embedded
2243 system where you want the system to reboot
2244 automatically as fast as possible, but it may be
2245 useful during development since you can try to debug
2246 the conditions that lead to the situation.
2248 CONFIG_NET_RETRY_COUNT
2250 This variable defines the number of retries for
2251 network operations like ARP, RARP, TFTP, or BOOTP
2252 before giving up the operation. If not defined, a
2253 default value of 5 is used.
2257 Timeout waiting for an ARP reply in milliseconds.
2261 Timeout in milliseconds used in NFS protocol.
2262 If you encounter "ERROR: Cannot umount" in nfs command,
2263 try longer timeout such as
2264 #define CONFIG_NFS_TIMEOUT 10000UL
2266 - Command Interpreter:
2267 CONFIG_AUTO_COMPLETE
2269 Enable auto completion of commands using TAB.
2271 Note that this feature has NOT been implemented yet
2272 for the "hush" shell.
2275 CONFIG_SYS_HUSH_PARSER
2277 Define this variable to enable the "hush" shell (from
2278 Busybox) as command line interpreter, thus enabling
2279 powerful command line syntax like
2280 if...then...else...fi conditionals or `&&' and '||'
2281 constructs ("shell scripts").
2283 If undefined, you get the old, much simpler behaviour
2284 with a somewhat smaller memory footprint.
2287 CONFIG_SYS_PROMPT_HUSH_PS2
2289 This defines the secondary prompt string, which is
2290 printed when the command interpreter needs more input
2291 to complete a command. Usually "> ".
2295 In the current implementation, the local variables
2296 space and global environment variables space are
2297 separated. Local variables are those you define by
2298 simply typing `name=value'. To access a local
2299 variable later on, you have write `$name' or
2300 `${name}'; to execute the contents of a variable
2301 directly type `$name' at the command prompt.
2303 Global environment variables are those you use
2304 setenv/printenv to work with. To run a command stored
2305 in such a variable, you need to use the run command,
2306 and you must not use the '$' sign to access them.
2308 To store commands and special characters in a
2309 variable, please use double quotation marks
2310 surrounding the whole text of the variable, instead
2311 of the backslashes before semicolons and special
2314 - Commandline Editing and History:
2315 CONFIG_CMDLINE_EDITING
2317 Enable editing and History functions for interactive
2318 commandline input operations
2320 - Default Environment:
2321 CONFIG_EXTRA_ENV_SETTINGS
2323 Define this to contain any number of null terminated
2324 strings (variable = value pairs) that will be part of
2325 the default environment compiled into the boot image.
2327 For example, place something like this in your
2328 board's config file:
2330 #define CONFIG_EXTRA_ENV_SETTINGS \
2334 Warning: This method is based on knowledge about the
2335 internal format how the environment is stored by the
2336 U-Boot code. This is NOT an official, exported
2337 interface! Although it is unlikely that this format
2338 will change soon, there is no guarantee either.
2339 You better know what you are doing here.
2341 Note: overly (ab)use of the default environment is
2342 discouraged. Make sure to check other ways to preset
2343 the environment like the "source" command or the
2346 CONFIG_ENV_VARS_UBOOT_CONFIG
2348 Define this in order to add variables describing the
2349 U-Boot build configuration to the default environment.
2350 These will be named arch, cpu, board, vendor, and soc.
2352 Enabling this option will cause the following to be defined:
2360 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2362 Define this in order to add variables describing certain
2363 run-time determined information about the hardware to the
2364 environment. These will be named board_name, board_rev.
2366 - DataFlash Support:
2367 CONFIG_HAS_DATAFLASH
2369 Defining this option enables DataFlash features and
2370 allows to read/write in Dataflash via the standard
2373 - Serial Flash support
2376 Defining this option enables SPI flash commands
2377 'sf probe/read/write/erase/update'.
2379 Usage requires an initial 'probe' to define the serial
2380 flash parameters, followed by read/write/erase/update
2383 The following defaults may be provided by the platform
2384 to handle the common case when only a single serial
2385 flash is present on the system.
2387 CONFIG_SF_DEFAULT_BUS Bus identifier
2388 CONFIG_SF_DEFAULT_CS Chip-select
2389 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2390 CONFIG_SF_DEFAULT_SPEED in Hz
2392 - SystemACE Support:
2395 Adding this option adds support for Xilinx SystemACE
2396 chips attached via some sort of local bus. The address
2397 of the chip must also be defined in the
2398 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2400 #define CONFIG_SYSTEMACE
2401 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2403 When SystemACE support is added, the "ace" device type
2404 becomes available to the fat commands, i.e. fatls.
2406 - TFTP Fixed UDP Port:
2409 If this is defined, the environment variable tftpsrcp
2410 is used to supply the TFTP UDP source port value.
2411 If tftpsrcp isn't defined, the normal pseudo-random port
2412 number generator is used.
2414 Also, the environment variable tftpdstp is used to supply
2415 the TFTP UDP destination port value. If tftpdstp isn't
2416 defined, the normal port 69 is used.
2418 The purpose for tftpsrcp is to allow a TFTP server to
2419 blindly start the TFTP transfer using the pre-configured
2420 target IP address and UDP port. This has the effect of
2421 "punching through" the (Windows XP) firewall, allowing
2422 the remainder of the TFTP transfer to proceed normally.
2423 A better solution is to properly configure the firewall,
2424 but sometimes that is not allowed.
2429 This enables a generic 'hash' command which can produce
2430 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2434 Enable the hash verify command (hash -v). This adds to code
2437 CONFIG_SHA1 - support SHA1 hashing
2438 CONFIG_SHA256 - support SHA256 hashing
2440 Note: There is also a sha1sum command, which should perhaps
2441 be deprecated in favour of 'hash sha1'.
2443 - Show boot progress:
2444 CONFIG_SHOW_BOOT_PROGRESS
2446 Defining this option allows to add some board-
2447 specific code (calling a user-provided function
2448 "show_boot_progress(int)") that enables you to show
2449 the system's boot progress on some display (for
2450 example, some LED's) on your board. At the moment,
2451 the following checkpoints are implemented:
2453 - Detailed boot stage timing
2455 Define this option to get detailed timing of each stage
2456 of the boot process.
2458 CONFIG_BOOTSTAGE_USER_COUNT
2459 This is the number of available user bootstage records.
2460 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2461 a new ID will be allocated from this stash. If you exceed
2462 the limit, recording will stop.
2464 CONFIG_BOOTSTAGE_REPORT
2465 Define this to print a report before boot, similar to this:
2467 Timer summary in microseconds:
2470 3,575,678 3,575,678 board_init_f start
2471 3,575,695 17 arch_cpu_init A9
2472 3,575,777 82 arch_cpu_init done
2473 3,659,598 83,821 board_init_r start
2474 3,910,375 250,777 main_loop
2475 29,916,167 26,005,792 bootm_start
2476 30,361,327 445,160 start_kernel
2478 CONFIG_CMD_BOOTSTAGE
2479 Add a 'bootstage' command which supports printing a report
2480 and un/stashing of bootstage data.
2482 CONFIG_BOOTSTAGE_FDT
2483 Stash the bootstage information in the FDT. A root 'bootstage'
2484 node is created with each bootstage id as a child. Each child
2485 has a 'name' property and either 'mark' containing the
2486 mark time in microsecond, or 'accum' containing the
2487 accumulated time for that bootstage id in microseconds.
2492 name = "board_init_f";
2501 Code in the Linux kernel can find this in /proc/devicetree.
2503 Legacy uImage format:
2506 1 common/cmd_bootm.c before attempting to boot an image
2507 -1 common/cmd_bootm.c Image header has bad magic number
2508 2 common/cmd_bootm.c Image header has correct magic number
2509 -2 common/cmd_bootm.c Image header has bad checksum
2510 3 common/cmd_bootm.c Image header has correct checksum
2511 -3 common/cmd_bootm.c Image data has bad checksum
2512 4 common/cmd_bootm.c Image data has correct checksum
2513 -4 common/cmd_bootm.c Image is for unsupported architecture
2514 5 common/cmd_bootm.c Architecture check OK
2515 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2516 6 common/cmd_bootm.c Image Type check OK
2517 -6 common/cmd_bootm.c gunzip uncompression error
2518 -7 common/cmd_bootm.c Unimplemented compression type
2519 7 common/cmd_bootm.c Uncompression OK
2520 8 common/cmd_bootm.c No uncompress/copy overwrite error
2521 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2523 9 common/image.c Start initial ramdisk verification
2524 -10 common/image.c Ramdisk header has bad magic number
2525 -11 common/image.c Ramdisk header has bad checksum
2526 10 common/image.c Ramdisk header is OK
2527 -12 common/image.c Ramdisk data has bad checksum
2528 11 common/image.c Ramdisk data has correct checksum
2529 12 common/image.c Ramdisk verification complete, start loading
2530 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2531 13 common/image.c Start multifile image verification
2532 14 common/image.c No initial ramdisk, no multifile, continue.
2534 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2536 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2537 -31 post/post.c POST test failed, detected by post_output_backlog()
2538 -32 post/post.c POST test failed, detected by post_run_single()
2540 34 common/cmd_doc.c before loading a Image from a DOC device
2541 -35 common/cmd_doc.c Bad usage of "doc" command
2542 35 common/cmd_doc.c correct usage of "doc" command
2543 -36 common/cmd_doc.c No boot device
2544 36 common/cmd_doc.c correct boot device
2545 -37 common/cmd_doc.c Unknown Chip ID on boot device
2546 37 common/cmd_doc.c correct chip ID found, device available
2547 -38 common/cmd_doc.c Read Error on boot device
2548 38 common/cmd_doc.c reading Image header from DOC device OK
2549 -39 common/cmd_doc.c Image header has bad magic number
2550 39 common/cmd_doc.c Image header has correct magic number
2551 -40 common/cmd_doc.c Error reading Image from DOC device
2552 40 common/cmd_doc.c Image header has correct magic number
2553 41 common/cmd_ide.c before loading a Image from a IDE device
2554 -42 common/cmd_ide.c Bad usage of "ide" command
2555 42 common/cmd_ide.c correct usage of "ide" command
2556 -43 common/cmd_ide.c No boot device
2557 43 common/cmd_ide.c boot device found
2558 -44 common/cmd_ide.c Device not available
2559 44 common/cmd_ide.c Device available
2560 -45 common/cmd_ide.c wrong partition selected
2561 45 common/cmd_ide.c partition selected
2562 -46 common/cmd_ide.c Unknown partition table
2563 46 common/cmd_ide.c valid partition table found
2564 -47 common/cmd_ide.c Invalid partition type
2565 47 common/cmd_ide.c correct partition type
2566 -48 common/cmd_ide.c Error reading Image Header on boot device
2567 48 common/cmd_ide.c reading Image Header from IDE device OK
2568 -49 common/cmd_ide.c Image header has bad magic number
2569 49 common/cmd_ide.c Image header has correct magic number
2570 -50 common/cmd_ide.c Image header has bad checksum
2571 50 common/cmd_ide.c Image header has correct checksum
2572 -51 common/cmd_ide.c Error reading Image from IDE device
2573 51 common/cmd_ide.c reading Image from IDE device OK
2574 52 common/cmd_nand.c before loading a Image from a NAND device
2575 -53 common/cmd_nand.c Bad usage of "nand" command
2576 53 common/cmd_nand.c correct usage of "nand" command
2577 -54 common/cmd_nand.c No boot device
2578 54 common/cmd_nand.c boot device found
2579 -55 common/cmd_nand.c Unknown Chip ID on boot device
2580 55 common/cmd_nand.c correct chip ID found, device available
2581 -56 common/cmd_nand.c Error reading Image Header on boot device
2582 56 common/cmd_nand.c reading Image Header from NAND device OK
2583 -57 common/cmd_nand.c Image header has bad magic number
2584 57 common/cmd_nand.c Image header has correct magic number
2585 -58 common/cmd_nand.c Error reading Image from NAND device
2586 58 common/cmd_nand.c reading Image from NAND device OK
2588 -60 common/env_common.c Environment has a bad CRC, using default
2590 64 net/eth.c starting with Ethernet configuration.
2591 -64 net/eth.c no Ethernet found.
2592 65 net/eth.c Ethernet found.
2594 -80 common/cmd_net.c usage wrong
2595 80 common/cmd_net.c before calling NetLoop()
2596 -81 common/cmd_net.c some error in NetLoop() occurred
2597 81 common/cmd_net.c NetLoop() back without error
2598 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2599 82 common/cmd_net.c trying automatic boot
2600 83 common/cmd_net.c running "source" command
2601 -83 common/cmd_net.c some error in automatic boot or "source" command
2602 84 common/cmd_net.c end without errors
2607 100 common/cmd_bootm.c Kernel FIT Image has correct format
2608 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2609 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2610 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2611 102 common/cmd_bootm.c Kernel unit name specified
2612 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2613 103 common/cmd_bootm.c Found configuration node
2614 104 common/cmd_bootm.c Got kernel subimage node offset
2615 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2616 105 common/cmd_bootm.c Kernel subimage hash verification OK
2617 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2618 106 common/cmd_bootm.c Architecture check OK
2619 -106 common/cmd_bootm.c Kernel subimage has wrong type
2620 107 common/cmd_bootm.c Kernel subimage type OK
2621 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2622 108 common/cmd_bootm.c Got kernel subimage data/size
2623 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2624 -109 common/cmd_bootm.c Can't get kernel subimage type
2625 -110 common/cmd_bootm.c Can't get kernel subimage comp
2626 -111 common/cmd_bootm.c Can't get kernel subimage os
2627 -112 common/cmd_bootm.c Can't get kernel subimage load address
2628 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2630 120 common/image.c Start initial ramdisk verification
2631 -120 common/image.c Ramdisk FIT image has incorrect format
2632 121 common/image.c Ramdisk FIT image has correct format
2633 122 common/image.c No ramdisk subimage unit name, using configuration
2634 -122 common/image.c Can't get configuration for ramdisk subimage
2635 123 common/image.c Ramdisk unit name specified
2636 -124 common/image.c Can't get ramdisk subimage node offset
2637 125 common/image.c Got ramdisk subimage node offset
2638 -125 common/image.c Ramdisk subimage hash verification failed
2639 126 common/image.c Ramdisk subimage hash verification OK
2640 -126 common/image.c Ramdisk subimage for unsupported architecture
2641 127 common/image.c Architecture check OK
2642 -127 common/image.c Can't get ramdisk subimage data/size
2643 128 common/image.c Got ramdisk subimage data/size
2644 129 common/image.c Can't get ramdisk load address
2645 -129 common/image.c Got ramdisk load address
2647 -130 common/cmd_doc.c Incorrect FIT image format
2648 131 common/cmd_doc.c FIT image format OK
2650 -140 common/cmd_ide.c Incorrect FIT image format
2651 141 common/cmd_ide.c FIT image format OK
2653 -150 common/cmd_nand.c Incorrect FIT image format
2654 151 common/cmd_nand.c FIT image format OK
2656 - FIT image support:
2658 Enable support for the FIT uImage format.
2660 CONFIG_FIT_BEST_MATCH
2661 When no configuration is explicitly selected, default to the
2662 one whose fdt's compatibility field best matches that of
2663 U-Boot itself. A match is considered "best" if it matches the
2664 most specific compatibility entry of U-Boot's fdt's root node.
2665 The order of entries in the configuration's fdt is ignored.
2667 - Standalone program support:
2668 CONFIG_STANDALONE_LOAD_ADDR
2670 This option defines a board specific value for the
2671 address where standalone program gets loaded, thus
2672 overwriting the architecture dependent default
2675 - Frame Buffer Address:
2678 Define CONFIG_FB_ADDR if you want to use specific
2679 address for frame buffer.
2680 Then system will reserve the frame buffer address to
2681 defined address instead of lcd_setmem (this function
2682 grabs the memory for frame buffer by panel's size).
2684 Please see board_init_f function.
2686 - Automatic software updates via TFTP server
2688 CONFIG_UPDATE_TFTP_CNT_MAX
2689 CONFIG_UPDATE_TFTP_MSEC_MAX
2691 These options enable and control the auto-update feature;
2692 for a more detailed description refer to doc/README.update.
2694 - MTD Support (mtdparts command, UBI support)
2697 Adds the MTD device infrastructure from the Linux kernel.
2698 Needed for mtdparts command support.
2700 CONFIG_MTD_PARTITIONS
2702 Adds the MTD partitioning infrastructure from the Linux
2703 kernel. Needed for UBI support.
2707 Enable building of SPL globally.
2710 LDSCRIPT for linking the SPL binary.
2713 Maximum binary size (text, data and rodata) of the SPL binary.
2715 CONFIG_SPL_TEXT_BASE
2716 TEXT_BASE for linking the SPL binary.
2718 CONFIG_SPL_RELOC_TEXT_BASE
2719 Address to relocate to. If unspecified, this is equal to
2720 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2722 CONFIG_SPL_BSS_START_ADDR
2723 Link address for the BSS within the SPL binary.
2725 CONFIG_SPL_BSS_MAX_SIZE
2726 Maximum binary size of the BSS section of the SPL binary.
2729 Adress of the start of the stack SPL will use
2731 CONFIG_SPL_RELOC_STACK
2732 Adress of the start of the stack SPL will use after
2733 relocation. If unspecified, this is equal to
2736 CONFIG_SYS_SPL_MALLOC_START
2737 Starting address of the malloc pool used in SPL.
2739 CONFIG_SYS_SPL_MALLOC_SIZE
2740 The size of the malloc pool used in SPL.
2742 CONFIG_SPL_FRAMEWORK
2743 Enable the SPL framework under common/. This framework
2744 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2745 NAND loading of the Linux Kernel.
2747 CONFIG_SPL_DISPLAY_PRINT
2748 For ARM, enable an optional function to print more information
2749 about the running system.
2751 CONFIG_SPL_INIT_MINIMAL
2752 Arch init code should be built for a very small image
2754 CONFIG_SPL_LIBCOMMON_SUPPORT
2755 Support for common/libcommon.o in SPL binary
2757 CONFIG_SPL_LIBDISK_SUPPORT
2758 Support for disk/libdisk.o in SPL binary
2760 CONFIG_SPL_I2C_SUPPORT
2761 Support for drivers/i2c/libi2c.o in SPL binary
2763 CONFIG_SPL_GPIO_SUPPORT
2764 Support for drivers/gpio/libgpio.o in SPL binary
2766 CONFIG_SPL_MMC_SUPPORT
2767 Support for drivers/mmc/libmmc.o in SPL binary
2769 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2770 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2771 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2772 Address, size and partition on the MMC to load U-Boot from
2773 when the MMC is being used in raw mode.
2775 CONFIG_SPL_FAT_SUPPORT
2776 Support for fs/fat/libfat.o in SPL binary
2778 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2779 Filename to read to load U-Boot when reading from FAT
2781 CONFIG_SPL_NAND_BASE
2782 Include nand_base.c in the SPL. Requires
2783 CONFIG_SPL_NAND_DRIVERS.
2785 CONFIG_SPL_NAND_DRIVERS
2786 SPL uses normal NAND drivers, not minimal drivers.
2789 Include standard software ECC in the SPL
2791 CONFIG_SPL_NAND_SIMPLE
2792 Support for NAND boot using simple NAND drivers that
2793 expose the cmd_ctrl() interface.
2795 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2796 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2797 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2798 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2799 CONFIG_SYS_NAND_ECCBYTES
2800 Defines the size and behavior of the NAND that SPL uses
2803 CONFIG_SYS_NAND_U_BOOT_OFFS
2804 Location in NAND to read U-Boot from
2806 CONFIG_SYS_NAND_U_BOOT_DST
2807 Location in memory to load U-Boot to
2809 CONFIG_SYS_NAND_U_BOOT_SIZE
2810 Size of image to load
2812 CONFIG_SYS_NAND_U_BOOT_START
2813 Entry point in loaded image to jump to
2815 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2816 Define this if you need to first read the OOB and then the
2817 data. This is used for example on davinci plattforms.
2819 CONFIG_SPL_OMAP3_ID_NAND
2820 Support for an OMAP3-specific set of functions to return the
2821 ID and MFR of the first attached NAND chip, if present.
2823 CONFIG_SPL_SERIAL_SUPPORT
2824 Support for drivers/serial/libserial.o in SPL binary
2826 CONFIG_SPL_SPI_FLASH_SUPPORT
2827 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2829 CONFIG_SPL_SPI_SUPPORT
2830 Support for drivers/spi/libspi.o in SPL binary
2832 CONFIG_SPL_RAM_DEVICE
2833 Support for running image already present in ram, in SPL binary
2835 CONFIG_SPL_LIBGENERIC_SUPPORT
2836 Support for lib/libgeneric.o in SPL binary
2839 Final target image containing SPL and payload. Some SPLs
2840 use an arch-specific makefile fragment instead, for
2841 example if more than one image needs to be produced.
2846 [so far only for SMDK2400 boards]
2848 - Modem support enable:
2849 CONFIG_MODEM_SUPPORT
2851 - RTS/CTS Flow control enable:
2854 - Modem debug support:
2855 CONFIG_MODEM_SUPPORT_DEBUG
2857 Enables debugging stuff (char screen[1024], dbg())
2858 for modem support. Useful only with BDI2000.
2860 - Interrupt support (PPC):
2862 There are common interrupt_init() and timer_interrupt()
2863 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2864 for CPU specific initialization. interrupt_init_cpu()
2865 should set decrementer_count to appropriate value. If
2866 CPU resets decrementer automatically after interrupt
2867 (ppc4xx) it should set decrementer_count to zero.
2868 timer_interrupt() calls timer_interrupt_cpu() for CPU
2869 specific handling. If board has watchdog / status_led
2870 / other_activity_monitor it works automatically from
2871 general timer_interrupt().
2875 In the target system modem support is enabled when a
2876 specific key (key combination) is pressed during
2877 power-on. Otherwise U-Boot will boot normally
2878 (autoboot). The key_pressed() function is called from
2879 board_init(). Currently key_pressed() is a dummy
2880 function, returning 1 and thus enabling modem
2883 If there are no modem init strings in the
2884 environment, U-Boot proceed to autoboot; the
2885 previous output (banner, info printfs) will be
2888 See also: doc/README.Modem
2890 Board initialization settings:
2891 ------------------------------
2893 During Initialization u-boot calls a number of board specific functions
2894 to allow the preparation of board specific prerequisites, e.g. pin setup
2895 before drivers are initialized. To enable these callbacks the
2896 following configuration macros have to be defined. Currently this is
2897 architecture specific, so please check arch/your_architecture/lib/board.c
2898 typically in board_init_f() and board_init_r().
2900 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2901 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2902 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2903 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2905 Configuration Settings:
2906 -----------------------
2908 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2909 undefine this when you're short of memory.
2911 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2912 width of the commands listed in the 'help' command output.
2914 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2915 prompt for user input.
2917 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2919 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2921 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2923 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2924 the application (usually a Linux kernel) when it is
2927 - CONFIG_SYS_BAUDRATE_TABLE:
2928 List of legal baudrate settings for this board.
2930 - CONFIG_SYS_CONSOLE_INFO_QUIET
2931 Suppress display of console information at boot.
2933 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2934 If the board specific function
2935 extern int overwrite_console (void);
2936 returns 1, the stdin, stderr and stdout are switched to the
2937 serial port, else the settings in the environment are used.
2939 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2940 Enable the call to overwrite_console().
2942 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2943 Enable overwrite of previous console environment settings.
2945 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2946 Begin and End addresses of the area used by the
2949 - CONFIG_SYS_ALT_MEMTEST:
2950 Enable an alternate, more extensive memory test.
2952 - CONFIG_SYS_MEMTEST_SCRATCH:
2953 Scratch address used by the alternate memory test
2954 You only need to set this if address zero isn't writeable
2956 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2957 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2958 this specified memory area will get subtracted from the top
2959 (end) of RAM and won't get "touched" at all by U-Boot. By
2960 fixing up gd->ram_size the Linux kernel should gets passed
2961 the now "corrected" memory size and won't touch it either.
2962 This should work for arch/ppc and arch/powerpc. Only Linux
2963 board ports in arch/powerpc with bootwrapper support that
2964 recalculate the memory size from the SDRAM controller setup
2965 will have to get fixed in Linux additionally.
2967 This option can be used as a workaround for the 440EPx/GRx
2968 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2971 WARNING: Please make sure that this value is a multiple of
2972 the Linux page size (normally 4k). If this is not the case,
2973 then the end address of the Linux memory will be located at a
2974 non page size aligned address and this could cause major
2977 - CONFIG_SYS_TFTP_LOADADDR:
2978 Default load address for network file downloads
2980 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2981 Enable temporary baudrate change while serial download
2983 - CONFIG_SYS_SDRAM_BASE:
2984 Physical start address of SDRAM. _Must_ be 0 here.
2986 - CONFIG_SYS_MBIO_BASE:
2987 Physical start address of Motherboard I/O (if using a
2990 - CONFIG_SYS_FLASH_BASE:
2991 Physical start address of Flash memory.
2993 - CONFIG_SYS_MONITOR_BASE:
2994 Physical start address of boot monitor code (set by
2995 make config files to be same as the text base address
2996 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2997 CONFIG_SYS_FLASH_BASE when booting from flash.
2999 - CONFIG_SYS_MONITOR_LEN:
3000 Size of memory reserved for monitor code, used to
3001 determine _at_compile_time_ (!) if the environment is
3002 embedded within the U-Boot image, or in a separate
3005 - CONFIG_SYS_MALLOC_LEN:
3006 Size of DRAM reserved for malloc() use.
3008 - CONFIG_SYS_BOOTM_LEN:
3009 Normally compressed uImages are limited to an
3010 uncompressed size of 8 MBytes. If this is not enough,
3011 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3012 to adjust this setting to your needs.
3014 - CONFIG_SYS_BOOTMAPSZ:
3015 Maximum size of memory mapped by the startup code of
3016 the Linux kernel; all data that must be processed by
3017 the Linux kernel (bd_info, boot arguments, FDT blob if
3018 used) must be put below this limit, unless "bootm_low"
3019 enviroment variable is defined and non-zero. In such case
3020 all data for the Linux kernel must be between "bootm_low"
3021 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3022 variable "bootm_mapsize" will override the value of
3023 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3024 then the value in "bootm_size" will be used instead.
3026 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3027 Enable initrd_high functionality. If defined then the
3028 initrd_high feature is enabled and the bootm ramdisk subcommand
3031 - CONFIG_SYS_BOOT_GET_CMDLINE:
3032 Enables allocating and saving kernel cmdline in space between
3033 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3035 - CONFIG_SYS_BOOT_GET_KBD:
3036 Enables allocating and saving a kernel copy of the bd_info in
3037 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3039 - CONFIG_SYS_MAX_FLASH_BANKS:
3040 Max number of Flash memory banks
3042 - CONFIG_SYS_MAX_FLASH_SECT:
3043 Max number of sectors on a Flash chip
3045 - CONFIG_SYS_FLASH_ERASE_TOUT:
3046 Timeout for Flash erase operations (in ms)
3048 - CONFIG_SYS_FLASH_WRITE_TOUT:
3049 Timeout for Flash write operations (in ms)
3051 - CONFIG_SYS_FLASH_LOCK_TOUT
3052 Timeout for Flash set sector lock bit operation (in ms)
3054 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3055 Timeout for Flash clear lock bits operation (in ms)
3057 - CONFIG_SYS_FLASH_PROTECTION
3058 If defined, hardware flash sectors protection is used
3059 instead of U-Boot software protection.
3061 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3063 Enable TFTP transfers directly to flash memory;
3064 without this option such a download has to be
3065 performed in two steps: (1) download to RAM, and (2)
3066 copy from RAM to flash.
3068 The two-step approach is usually more reliable, since
3069 you can check if the download worked before you erase
3070 the flash, but in some situations (when system RAM is
3071 too limited to allow for a temporary copy of the
3072 downloaded image) this option may be very useful.
3074 - CONFIG_SYS_FLASH_CFI:
3075 Define if the flash driver uses extra elements in the
3076 common flash structure for storing flash geometry.
3078 - CONFIG_FLASH_CFI_DRIVER
3079 This option also enables the building of the cfi_flash driver
3080 in the drivers directory
3082 - CONFIG_FLASH_CFI_MTD
3083 This option enables the building of the cfi_mtd driver
3084 in the drivers directory. The driver exports CFI flash
3087 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3088 Use buffered writes to flash.
3090 - CONFIG_FLASH_SPANSION_S29WS_N
3091 s29ws-n MirrorBit flash has non-standard addresses for buffered
3094 - CONFIG_SYS_FLASH_QUIET_TEST
3095 If this option is defined, the common CFI flash doesn't
3096 print it's warning upon not recognized FLASH banks. This
3097 is useful, if some of the configured banks are only
3098 optionally available.
3100 - CONFIG_FLASH_SHOW_PROGRESS
3101 If defined (must be an integer), print out countdown
3102 digits and dots. Recommended value: 45 (9..1) for 80
3103 column displays, 15 (3..1) for 40 column displays.
3105 - CONFIG_SYS_RX_ETH_BUFFER:
3106 Defines the number of Ethernet receive buffers. On some
3107 Ethernet controllers it is recommended to set this value
3108 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3109 buffers can be full shortly after enabling the interface
3110 on high Ethernet traffic.
3111 Defaults to 4 if not defined.
3113 - CONFIG_ENV_MAX_ENTRIES
3115 Maximum number of entries in the hash table that is used
3116 internally to store the environment settings. The default
3117 setting is supposed to be generous and should work in most
3118 cases. This setting can be used to tune behaviour; see
3119 lib/hashtable.c for details.
3121 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3122 - CONFIG_ENV_FLAGS_LIST_STATIC
3123 Enable validation of the values given to enviroment variables when
3124 calling env set. Variables can be restricted to only decimal,
3125 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3126 the variables can also be restricted to IP address or MAC address.
3128 The format of the list is:
3129 type_attribute = [s|d|x|b|i|m]
3130 attributes = type_attribute
3131 entry = variable_name[:attributes]
3134 The type attributes are:
3135 s - String (default)
3138 b - Boolean ([1yYtT|0nNfF])
3142 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3143 Define this to a list (string) to define the ".flags"
3144 envirnoment variable in the default or embedded environment.
3146 - CONFIG_ENV_FLAGS_LIST_STATIC
3147 Define this to a list (string) to define validation that
3148 should be done if an entry is not found in the ".flags"
3149 environment variable. To override a setting in the static
3150 list, simply add an entry for the same variable name to the
3153 The following definitions that deal with the placement and management
3154 of environment data (variable area); in general, we support the
3155 following configurations:
3157 - CONFIG_BUILD_ENVCRC:
3159 Builds up envcrc with the target environment so that external utils
3160 may easily extract it and embed it in final U-Boot images.
3162 - CONFIG_ENV_IS_IN_FLASH:
3164 Define this if the environment is in flash memory.
3166 a) The environment occupies one whole flash sector, which is
3167 "embedded" in the text segment with the U-Boot code. This
3168 happens usually with "bottom boot sector" or "top boot
3169 sector" type flash chips, which have several smaller
3170 sectors at the start or the end. For instance, such a
3171 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3172 such a case you would place the environment in one of the
3173 4 kB sectors - with U-Boot code before and after it. With
3174 "top boot sector" type flash chips, you would put the
3175 environment in one of the last sectors, leaving a gap
3176 between U-Boot and the environment.
3178 - CONFIG_ENV_OFFSET:
3180 Offset of environment data (variable area) to the
3181 beginning of flash memory; for instance, with bottom boot
3182 type flash chips the second sector can be used: the offset
3183 for this sector is given here.
3185 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3189 This is just another way to specify the start address of
3190 the flash sector containing the environment (instead of
3193 - CONFIG_ENV_SECT_SIZE:
3195 Size of the sector containing the environment.
3198 b) Sometimes flash chips have few, equal sized, BIG sectors.
3199 In such a case you don't want to spend a whole sector for
3204 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3205 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3206 of this flash sector for the environment. This saves
3207 memory for the RAM copy of the environment.
3209 It may also save flash memory if you decide to use this
3210 when your environment is "embedded" within U-Boot code,
3211 since then the remainder of the flash sector could be used
3212 for U-Boot code. It should be pointed out that this is
3213 STRONGLY DISCOURAGED from a robustness point of view:
3214 updating the environment in flash makes it always
3215 necessary to erase the WHOLE sector. If something goes
3216 wrong before the contents has been restored from a copy in
3217 RAM, your target system will be dead.
3219 - CONFIG_ENV_ADDR_REDUND
3220 CONFIG_ENV_SIZE_REDUND
3222 These settings describe a second storage area used to hold
3223 a redundant copy of the environment data, so that there is
3224 a valid backup copy in case there is a power failure during
3225 a "saveenv" operation.
3227 BE CAREFUL! Any changes to the flash layout, and some changes to the
3228 source code will make it necessary to adapt <board>/u-boot.lds*
3232 - CONFIG_ENV_IS_IN_NVRAM:
3234 Define this if you have some non-volatile memory device
3235 (NVRAM, battery buffered SRAM) which you want to use for the
3241 These two #defines are used to determine the memory area you
3242 want to use for environment. It is assumed that this memory
3243 can just be read and written to, without any special
3246 BE CAREFUL! The first access to the environment happens quite early
3247 in U-Boot initalization (when we try to get the setting of for the
3248 console baudrate). You *MUST* have mapped your NVRAM area then, or
3251 Please note that even with NVRAM we still use a copy of the
3252 environment in RAM: we could work on NVRAM directly, but we want to
3253 keep settings there always unmodified except somebody uses "saveenv"
3254 to save the current settings.
3257 - CONFIG_ENV_IS_IN_EEPROM:
3259 Use this if you have an EEPROM or similar serial access
3260 device and a driver for it.
3262 - CONFIG_ENV_OFFSET:
3265 These two #defines specify the offset and size of the
3266 environment area within the total memory of your EEPROM.
3268 - CONFIG_SYS_I2C_EEPROM_ADDR:
3269 If defined, specified the chip address of the EEPROM device.
3270 The default address is zero.
3272 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3273 If defined, the number of bits used to address bytes in a
3274 single page in the EEPROM device. A 64 byte page, for example
3275 would require six bits.
3277 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3278 If defined, the number of milliseconds to delay between
3279 page writes. The default is zero milliseconds.
3281 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3282 The length in bytes of the EEPROM memory array address. Note
3283 that this is NOT the chip address length!
3285 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3286 EEPROM chips that implement "address overflow" are ones
3287 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3288 address and the extra bits end up in the "chip address" bit
3289 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3292 Note that we consider the length of the address field to
3293 still be one byte because the extra address bits are hidden
3294 in the chip address.
3296 - CONFIG_SYS_EEPROM_SIZE:
3297 The size in bytes of the EEPROM device.
3299 - CONFIG_ENV_EEPROM_IS_ON_I2C
3300 define this, if you have I2C and SPI activated, and your
3301 EEPROM, which holds the environment, is on the I2C bus.
3303 - CONFIG_I2C_ENV_EEPROM_BUS
3304 if you have an Environment on an EEPROM reached over
3305 I2C muxes, you can define here, how to reach this
3306 EEPROM. For example:
3308 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3310 EEPROM which holds the environment, is reached over
3311 a pca9547 i2c mux with address 0x70, channel 3.
3313 - CONFIG_ENV_IS_IN_DATAFLASH:
3315 Define this if you have a DataFlash memory device which you
3316 want to use for the environment.
3318 - CONFIG_ENV_OFFSET:
3322 These three #defines specify the offset and size of the
3323 environment area within the total memory of your DataFlash placed
3324 at the specified address.
3326 - CONFIG_ENV_IS_IN_REMOTE:
3328 Define this if you have a remote memory space which you
3329 want to use for the local device's environment.
3334 These two #defines specify the address and size of the
3335 environment area within the remote memory space. The
3336 local device can get the environment from remote memory
3337 space by SRIO or PCIE links.
3339 BE CAREFUL! For some special cases, the local device can not use
3340 "saveenv" command. For example, the local device will get the
3341 environment stored in a remote NOR flash by SRIO or PCIE link,
3342 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3344 - CONFIG_ENV_IS_IN_NAND:
3346 Define this if you have a NAND device which you want to use
3347 for the environment.
3349 - CONFIG_ENV_OFFSET:
3352 These two #defines specify the offset and size of the environment
3353 area within the first NAND device. CONFIG_ENV_OFFSET must be
3354 aligned to an erase block boundary.
3356 - CONFIG_ENV_OFFSET_REDUND (optional):
3358 This setting describes a second storage area of CONFIG_ENV_SIZE
3359 size used to hold a redundant copy of the environment data, so
3360 that there is a valid backup copy in case there is a power failure
3361 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3362 aligned to an erase block boundary.
3364 - CONFIG_ENV_RANGE (optional):
3366 Specifies the length of the region in which the environment
3367 can be written. This should be a multiple of the NAND device's
3368 block size. Specifying a range with more erase blocks than
3369 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3370 the range to be avoided.
3372 - CONFIG_ENV_OFFSET_OOB (optional):
3374 Enables support for dynamically retrieving the offset of the
3375 environment from block zero's out-of-band data. The
3376 "nand env.oob" command can be used to record this offset.
3377 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3378 using CONFIG_ENV_OFFSET_OOB.
3380 - CONFIG_NAND_ENV_DST
3382 Defines address in RAM to which the nand_spl code should copy the
3383 environment. If redundant environment is used, it will be copied to
3384 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3386 - CONFIG_SYS_SPI_INIT_OFFSET
3388 Defines offset to the initial SPI buffer area in DPRAM. The
3389 area is used at an early stage (ROM part) if the environment
3390 is configured to reside in the SPI EEPROM: We need a 520 byte
3391 scratch DPRAM area. It is used between the two initialization
3392 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3393 to be a good choice since it makes it far enough from the
3394 start of the data area as well as from the stack pointer.
3396 Please note that the environment is read-only until the monitor
3397 has been relocated to RAM and a RAM copy of the environment has been
3398 created; also, when using EEPROM you will have to use getenv_f()
3399 until then to read environment variables.
3401 The environment is protected by a CRC32 checksum. Before the monitor
3402 is relocated into RAM, as a result of a bad CRC you will be working
3403 with the compiled-in default environment - *silently*!!! [This is
3404 necessary, because the first environment variable we need is the
3405 "baudrate" setting for the console - if we have a bad CRC, we don't
3406 have any device yet where we could complain.]
3408 Note: once the monitor has been relocated, then it will complain if
3409 the default environment is used; a new CRC is computed as soon as you
3410 use the "saveenv" command to store a valid environment.
3412 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3413 Echo the inverted Ethernet link state to the fault LED.
3415 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3416 also needs to be defined.
3418 - CONFIG_SYS_FAULT_MII_ADDR:
3419 MII address of the PHY to check for the Ethernet link state.
3421 - CONFIG_NS16550_MIN_FUNCTIONS:
3422 Define this if you desire to only have use of the NS16550_init
3423 and NS16550_putc functions for the serial driver located at
3424 drivers/serial/ns16550.c. This option is useful for saving
3425 space for already greatly restricted images, including but not
3426 limited to NAND_SPL configurations.
3428 Low Level (hardware related) configuration options:
3429 ---------------------------------------------------
3431 - CONFIG_SYS_CACHELINE_SIZE:
3432 Cache Line Size of the CPU.
3434 - CONFIG_SYS_DEFAULT_IMMR:
3435 Default address of the IMMR after system reset.
3437 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3438 and RPXsuper) to be able to adjust the position of
3439 the IMMR register after a reset.
3441 - CONFIG_SYS_CCSRBAR_DEFAULT:
3442 Default (power-on reset) physical address of CCSR on Freescale
3445 - CONFIG_SYS_CCSRBAR:
3446 Virtual address of CCSR. On a 32-bit build, this is typically
3447 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3449 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3450 for cross-platform code that uses that macro instead.
3452 - CONFIG_SYS_CCSRBAR_PHYS:
3453 Physical address of CCSR. CCSR can be relocated to a new
3454 physical address, if desired. In this case, this macro should
3455 be set to that address. Otherwise, it should be set to the
3456 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3457 is typically relocated on 36-bit builds. It is recommended
3458 that this macro be defined via the _HIGH and _LOW macros:
3460 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3461 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3463 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3464 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3465 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3466 used in assembly code, so it must not contain typecasts or
3467 integer size suffixes (e.g. "ULL").
3469 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3470 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3471 used in assembly code, so it must not contain typecasts or
3472 integer size suffixes (e.g. "ULL").
3474 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3475 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3476 forced to a value that ensures that CCSR is not relocated.
3478 - Floppy Disk Support:
3479 CONFIG_SYS_FDC_DRIVE_NUMBER
3481 the default drive number (default value 0)
3483 CONFIG_SYS_ISA_IO_STRIDE
3485 defines the spacing between FDC chipset registers
3488 CONFIG_SYS_ISA_IO_OFFSET
3490 defines the offset of register from address. It
3491 depends on which part of the data bus is connected to
3492 the FDC chipset. (default value 0)
3494 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3495 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3498 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3499 fdc_hw_init() is called at the beginning of the FDC
3500 setup. fdc_hw_init() must be provided by the board
3501 source code. It is used to make hardware dependant
3505 Most IDE controllers were designed to be connected with PCI
3506 interface. Only few of them were designed for AHB interface.
3507 When software is doing ATA command and data transfer to
3508 IDE devices through IDE-AHB controller, some additional
3509 registers accessing to these kind of IDE-AHB controller
3512 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3513 DO NOT CHANGE unless you know exactly what you're
3514 doing! (11-4) [MPC8xx/82xx systems only]
3516 - CONFIG_SYS_INIT_RAM_ADDR:
3518 Start address of memory area that can be used for
3519 initial data and stack; please note that this must be
3520 writable memory that is working WITHOUT special
3521 initialization, i. e. you CANNOT use normal RAM which
3522 will become available only after programming the
3523 memory controller and running certain initialization
3526 U-Boot uses the following memory types:
3527 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3528 - MPC824X: data cache
3529 - PPC4xx: data cache
3531 - CONFIG_SYS_GBL_DATA_OFFSET:
3533 Offset of the initial data structure in the memory
3534 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3535 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3536 data is located at the end of the available space
3537 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3538 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3539 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3540 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3543 On the MPC824X (or other systems that use the data
3544 cache for initial memory) the address chosen for
3545 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3546 point to an otherwise UNUSED address space between
3547 the top of RAM and the start of the PCI space.
3549 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3551 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3553 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3555 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3557 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3559 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3561 - CONFIG_SYS_OR_TIMING_SDRAM:
3564 - CONFIG_SYS_MAMR_PTA:
3565 periodic timer for refresh
3567 - CONFIG_SYS_DER: Debug Event Register (37-47)
3569 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3570 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3571 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3572 CONFIG_SYS_BR1_PRELIM:
3573 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3575 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3576 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3577 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3578 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3580 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3581 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3582 Machine Mode Register and Memory Periodic Timer
3583 Prescaler definitions (SDRAM timing)
3585 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3586 enable I2C microcode relocation patch (MPC8xx);
3587 define relocation offset in DPRAM [DSP2]
3589 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3590 enable SMC microcode relocation patch (MPC8xx);
3591 define relocation offset in DPRAM [SMC1]
3593 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3594 enable SPI microcode relocation patch (MPC8xx);
3595 define relocation offset in DPRAM [SCC4]
3597 - CONFIG_SYS_USE_OSCCLK:
3598 Use OSCM clock mode on MBX8xx board. Be careful,
3599 wrong setting might damage your board. Read
3600 doc/README.MBX before setting this variable!
3602 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3603 Offset of the bootmode word in DPRAM used by post
3604 (Power On Self Tests). This definition overrides
3605 #define'd default value in commproc.h resp.
3608 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3609 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3610 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3611 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3612 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3613 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3614 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3615 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3616 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3618 - CONFIG_PCI_DISABLE_PCIE:
3619 Disable PCI-Express on systems where it is supported but not
3622 - CONFIG_PCI_ENUM_ONLY
3623 Only scan through and get the devices on the busses.
3624 Don't do any setup work, presumably because someone or
3625 something has already done it, and we don't need to do it
3626 a second time. Useful for platforms that are pre-booted
3627 by coreboot or similar.
3630 Chip has SRIO or not
3633 Board has SRIO 1 port available
3636 Board has SRIO 2 port available
3638 - CONFIG_SYS_SRIOn_MEM_VIRT:
3639 Virtual Address of SRIO port 'n' memory region
3641 - CONFIG_SYS_SRIOn_MEM_PHYS:
3642 Physical Address of SRIO port 'n' memory region
3644 - CONFIG_SYS_SRIOn_MEM_SIZE:
3645 Size of SRIO port 'n' memory region
3647 - CONFIG_SYS_NDFC_16
3648 Defined to tell the NDFC that the NAND chip is using a
3651 - CONFIG_SYS_NDFC_EBC0_CFG
3652 Sets the EBC0_CFG register for the NDFC. If not defined
3653 a default value will be used.
3656 Get DDR timing information from an I2C EEPROM. Common
3657 with pluggable memory modules such as SODIMMs
3660 I2C address of the SPD EEPROM
3662 - CONFIG_SYS_SPD_BUS_NUM
3663 If SPD EEPROM is on an I2C bus other than the first
3664 one, specify here. Note that the value must resolve
3665 to something your driver can deal with.
3667 - CONFIG_SYS_DDR_RAW_TIMING
3668 Get DDR timing information from other than SPD. Common with
3669 soldered DDR chips onboard without SPD. DDR raw timing
3670 parameters are extracted from datasheet and hard-coded into
3671 header files or board specific files.
3673 - CONFIG_FSL_DDR_INTERACTIVE
3674 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3676 - CONFIG_SYS_83XX_DDR_USES_CS0
3677 Only for 83xx systems. If specified, then DDR should
3678 be configured using CS0 and CS1 instead of CS2 and CS3.
3680 - CONFIG_ETHER_ON_FEC[12]
3681 Define to enable FEC[12] on a 8xx series processor.
3683 - CONFIG_FEC[12]_PHY
3684 Define to the hardcoded PHY address which corresponds
3685 to the given FEC; i. e.
3686 #define CONFIG_FEC1_PHY 4
3687 means that the PHY with address 4 is connected to FEC1
3689 When set to -1, means to probe for first available.
3691 - CONFIG_FEC[12]_PHY_NORXERR
3692 The PHY does not have a RXERR line (RMII only).
3693 (so program the FEC to ignore it).
3696 Enable RMII mode for all FECs.
3697 Note that this is a global option, we can't
3698 have one FEC in standard MII mode and another in RMII mode.
3700 - CONFIG_CRC32_VERIFY
3701 Add a verify option to the crc32 command.
3704 => crc32 -v <address> <count> <crc32>
3706 Where address/count indicate a memory area
3707 and crc32 is the correct crc32 which the
3711 Add the "loopw" memory command. This only takes effect if
3712 the memory commands are activated globally (CONFIG_CMD_MEM).
3715 Add the "mdc" and "mwc" memory commands. These are cyclic
3720 This command will print 4 bytes (10,11,12,13) each 500 ms.
3722 => mwc.l 100 12345678 10
3723 This command will write 12345678 to address 100 all 10 ms.
3725 This only takes effect if the memory commands are activated
3726 globally (CONFIG_CMD_MEM).
3728 - CONFIG_SKIP_LOWLEVEL_INIT
3729 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3730 low level initializations (like setting up the memory
3731 controller) are omitted and/or U-Boot does not
3732 relocate itself into RAM.
3734 Normally this variable MUST NOT be defined. The only
3735 exception is when U-Boot is loaded (to RAM) by some
3736 other boot loader or by a debugger which performs
3737 these initializations itself.
3740 Modifies the behaviour of start.S when compiling a loader
3741 that is executed before the actual U-Boot. E.g. when
3742 compiling a NAND SPL.
3744 - CONFIG_USE_ARCH_MEMCPY
3745 CONFIG_USE_ARCH_MEMSET
3746 If these options are used a optimized version of memcpy/memset will
3747 be used if available. These functions may be faster under some
3748 conditions but may increase the binary size.
3750 - CONFIG_X86_NO_RESET_VECTOR
3751 If defined, the x86 reset vector code is excluded. You will need
3752 to do this when U-Boot is running from Coreboot.
3754 - CONFIG_X86_NO_REAL_MODE
3755 If defined, x86 real mode code is omitted. This assumes a
3756 32-bit environment where such code is not needed. You will
3757 need to do this when U-Boot is running from Coreboot.
3760 Freescale QE/FMAN Firmware Support:
3761 -----------------------------------
3763 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3764 loading of "firmware", which is encoded in the QE firmware binary format.
3765 This firmware often needs to be loaded during U-Boot booting, so macros
3766 are used to identify the storage device (NOR flash, SPI, etc) and the address
3769 - CONFIG_SYS_QE_FMAN_FW_ADDR
3770 The address in the storage device where the firmware is located. The
3771 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3774 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3775 The maximum possible size of the firmware. The firmware binary format
3776 has a field that specifies the actual size of the firmware, but it
3777 might not be possible to read any part of the firmware unless some
3778 local storage is allocated to hold the entire firmware first.
3780 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3781 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3782 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3783 virtual address in NOR flash.
3785 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3786 Specifies that QE/FMAN firmware is located in NAND flash.
3787 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3789 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3790 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3791 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3793 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3794 Specifies that QE/FMAN firmware is located on the primary SPI
3795 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3797 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3798 Specifies that QE/FMAN firmware is located in the remote (master)
3799 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3800 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3801 window->master inbound window->master LAW->the ucode address in
3802 master's memory space.
3804 Building the Software:
3805 ======================
3807 Building U-Boot has been tested in several native build environments
3808 and in many different cross environments. Of course we cannot support
3809 all possibly existing versions of cross development tools in all
3810 (potentially obsolete) versions. In case of tool chain problems we
3811 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3812 which is extensively used to build and test U-Boot.
3814 If you are not using a native environment, it is assumed that you
3815 have GNU cross compiling tools available in your path. In this case,
3816 you must set the environment variable CROSS_COMPILE in your shell.
3817 Note that no changes to the Makefile or any other source files are
3818 necessary. For example using the ELDK on a 4xx CPU, please enter:
3820 $ CROSS_COMPILE=ppc_4xx-
3821 $ export CROSS_COMPILE
3823 Note: If you wish to generate Windows versions of the utilities in
3824 the tools directory you can use the MinGW toolchain
3825 (http://www.mingw.org). Set your HOST tools to the MinGW
3826 toolchain and execute 'make tools'. For example:
3828 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3830 Binaries such as tools/mkimage.exe will be created which can
3831 be executed on computers running Windows.
3833 U-Boot is intended to be simple to build. After installing the
3834 sources you must configure U-Boot for one specific board type. This
3839 where "NAME_config" is the name of one of the existing configu-
3840 rations; see boards.cfg for supported names.
3842 Note: for some board special configuration names may exist; check if
3843 additional information is available from the board vendor; for
3844 instance, the TQM823L systems are available without (standard)
3845 or with LCD support. You can select such additional "features"
3846 when choosing the configuration, i. e.
3849 - will configure for a plain TQM823L, i. e. no LCD support
3851 make TQM823L_LCD_config
3852 - will configure for a TQM823L with U-Boot console on LCD
3857 Finally, type "make all", and you should get some working U-Boot
3858 images ready for download to / installation on your system:
3860 - "u-boot.bin" is a raw binary image
3861 - "u-boot" is an image in ELF binary format
3862 - "u-boot.srec" is in Motorola S-Record format
3864 By default the build is performed locally and the objects are saved
3865 in the source directory. One of the two methods can be used to change
3866 this behavior and build U-Boot to some external directory:
3868 1. Add O= to the make command line invocations:
3870 make O=/tmp/build distclean
3871 make O=/tmp/build NAME_config
3872 make O=/tmp/build all
3874 2. Set environment variable BUILD_DIR to point to the desired location:
3876 export BUILD_DIR=/tmp/build
3881 Note that the command line "O=" setting overrides the BUILD_DIR environment
3885 Please be aware that the Makefiles assume you are using GNU make, so
3886 for instance on NetBSD you might need to use "gmake" instead of
3890 If the system board that you have is not listed, then you will need
3891 to port U-Boot to your hardware platform. To do this, follow these
3894 1. Add a new configuration option for your board to the toplevel
3895 "boards.cfg" file, using the existing entries as examples.
3896 Follow the instructions there to keep the boards in order.
3897 2. Create a new directory to hold your board specific code. Add any
3898 files you need. In your board directory, you will need at least
3899 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3900 3. Create a new configuration file "include/configs/<board>.h" for
3902 3. If you're porting U-Boot to a new CPU, then also create a new
3903 directory to hold your CPU specific code. Add any files you need.
3904 4. Run "make <board>_config" with your new name.
3905 5. Type "make", and you should get a working "u-boot.srec" file
3906 to be installed on your target system.
3907 6. Debug and solve any problems that might arise.
3908 [Of course, this last step is much harder than it sounds.]
3911 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3912 ==============================================================
3914 If you have modified U-Boot sources (for instance added a new board
3915 or support for new devices, a new CPU, etc.) you are expected to
3916 provide feedback to the other developers. The feedback normally takes
3917 the form of a "patch", i. e. a context diff against a certain (latest
3918 official or latest in the git repository) version of U-Boot sources.
3920 But before you submit such a patch, please verify that your modifi-
3921 cation did not break existing code. At least make sure that *ALL* of
3922 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3923 just run the "MAKEALL" script, which will configure and build U-Boot
3924 for ALL supported system. Be warned, this will take a while. You can
3925 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3926 environment variable to the script, i. e. to use the ELDK cross tools
3929 CROSS_COMPILE=ppc_8xx- MAKEALL
3931 or to build on a native PowerPC system you can type
3933 CROSS_COMPILE=' ' MAKEALL
3935 When using the MAKEALL script, the default behaviour is to build
3936 U-Boot in the source directory. This location can be changed by
3937 setting the BUILD_DIR environment variable. Also, for each target
3938 built, the MAKEALL script saves two log files (<target>.ERR and
3939 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3940 location can be changed by setting the MAKEALL_LOGDIR environment
3941 variable. For example:
3943 export BUILD_DIR=/tmp/build
3944 export MAKEALL_LOGDIR=/tmp/log
3945 CROSS_COMPILE=ppc_8xx- MAKEALL
3947 With the above settings build objects are saved in the /tmp/build,
3948 log files are saved in the /tmp/log and the source tree remains clean
3949 during the whole build process.
3952 See also "U-Boot Porting Guide" below.
3955 Monitor Commands - Overview:
3956 ============================
3958 go - start application at address 'addr'
3959 run - run commands in an environment variable
3960 bootm - boot application image from memory
3961 bootp - boot image via network using BootP/TFTP protocol
3962 bootz - boot zImage from memory
3963 tftpboot- boot image via network using TFTP protocol
3964 and env variables "ipaddr" and "serverip"
3965 (and eventually "gatewayip")
3966 tftpput - upload a file via network using TFTP protocol
3967 rarpboot- boot image via network using RARP/TFTP protocol
3968 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3969 loads - load S-Record file over serial line
3970 loadb - load binary file over serial line (kermit mode)
3972 mm - memory modify (auto-incrementing)
3973 nm - memory modify (constant address)
3974 mw - memory write (fill)
3976 cmp - memory compare
3977 crc32 - checksum calculation
3978 i2c - I2C sub-system
3979 sspi - SPI utility commands
3980 base - print or set address offset
3981 printenv- print environment variables
3982 setenv - set environment variables
3983 saveenv - save environment variables to persistent storage
3984 protect - enable or disable FLASH write protection
3985 erase - erase FLASH memory
3986 flinfo - print FLASH memory information
3987 nand - NAND memory operations (see doc/README.nand)
3988 bdinfo - print Board Info structure
3989 iminfo - print header information for application image
3990 coninfo - print console devices and informations
3991 ide - IDE sub-system
3992 loop - infinite loop on address range
3993 loopw - infinite write loop on address range
3994 mtest - simple RAM test
3995 icache - enable or disable instruction cache
3996 dcache - enable or disable data cache
3997 reset - Perform RESET of the CPU
3998 echo - echo args to console
3999 version - print monitor version
4000 help - print online help
4001 ? - alias for 'help'
4004 Monitor Commands - Detailed Description:
4005 ========================================
4009 For now: just type "help <command>".
4012 Environment Variables:
4013 ======================
4015 U-Boot supports user configuration using Environment Variables which
4016 can be made persistent by saving to Flash memory.
4018 Environment Variables are set using "setenv", printed using
4019 "printenv", and saved to Flash using "saveenv". Using "setenv"
4020 without a value can be used to delete a variable from the
4021 environment. As long as you don't save the environment you are
4022 working with an in-memory copy. In case the Flash area containing the
4023 environment is erased by accident, a default environment is provided.
4025 Some configuration options can be set using Environment Variables.
4027 List of environment variables (most likely not complete):
4029 baudrate - see CONFIG_BAUDRATE
4031 bootdelay - see CONFIG_BOOTDELAY
4033 bootcmd - see CONFIG_BOOTCOMMAND
4035 bootargs - Boot arguments when booting an RTOS image
4037 bootfile - Name of the image to load with TFTP
4039 bootm_low - Memory range available for image processing in the bootm
4040 command can be restricted. This variable is given as
4041 a hexadecimal number and defines lowest address allowed
4042 for use by the bootm command. See also "bootm_size"
4043 environment variable. Address defined by "bootm_low" is
4044 also the base of the initial memory mapping for the Linux
4045 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4048 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4049 This variable is given as a hexadecimal number and it
4050 defines the size of the memory region starting at base
4051 address bootm_low that is accessible by the Linux kernel
4052 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4053 as the default value if it is defined, and bootm_size is
4056 bootm_size - Memory range available for image processing in the bootm
4057 command can be restricted. This variable is given as
4058 a hexadecimal number and defines the size of the region
4059 allowed for use by the bootm command. See also "bootm_low"
4060 environment variable.
4062 updatefile - Location of the software update file on a TFTP server, used
4063 by the automatic software update feature. Please refer to
4064 documentation in doc/README.update for more details.
4066 autoload - if set to "no" (any string beginning with 'n'),
4067 "bootp" will just load perform a lookup of the
4068 configuration from the BOOTP server, but not try to
4069 load any image using TFTP
4071 autostart - if set to "yes", an image loaded using the "bootp",
4072 "rarpboot", "tftpboot" or "diskboot" commands will
4073 be automatically started (by internally calling
4076 If set to "no", a standalone image passed to the
4077 "bootm" command will be copied to the load address
4078 (and eventually uncompressed), but NOT be started.
4079 This can be used to load and uncompress arbitrary
4082 fdt_high - if set this restricts the maximum address that the
4083 flattened device tree will be copied into upon boot.
4084 For example, if you have a system with 1 GB memory
4085 at physical address 0x10000000, while Linux kernel
4086 only recognizes the first 704 MB as low memory, you
4087 may need to set fdt_high as 0x3C000000 to have the
4088 device tree blob be copied to the maximum address
4089 of the 704 MB low memory, so that Linux kernel can
4090 access it during the boot procedure.
4092 If this is set to the special value 0xFFFFFFFF then
4093 the fdt will not be copied at all on boot. For this
4094 to work it must reside in writable memory, have
4095 sufficient padding on the end of it for u-boot to
4096 add the information it needs into it, and the memory
4097 must be accessible by the kernel.
4099 fdtcontroladdr- if set this is the address of the control flattened
4100 device tree used by U-Boot when CONFIG_OF_CONTROL is
4103 i2cfast - (PPC405GP|PPC405EP only)
4104 if set to 'y' configures Linux I2C driver for fast
4105 mode (400kHZ). This environment variable is used in
4106 initialization code. So, for changes to be effective
4107 it must be saved and board must be reset.
4109 initrd_high - restrict positioning of initrd images:
4110 If this variable is not set, initrd images will be
4111 copied to the highest possible address in RAM; this
4112 is usually what you want since it allows for
4113 maximum initrd size. If for some reason you want to
4114 make sure that the initrd image is loaded below the
4115 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4116 variable to a value of "no" or "off" or "0".
4117 Alternatively, you can set it to a maximum upper
4118 address to use (U-Boot will still check that it
4119 does not overwrite the U-Boot stack and data).
4121 For instance, when you have a system with 16 MB
4122 RAM, and want to reserve 4 MB from use by Linux,
4123 you can do this by adding "mem=12M" to the value of
4124 the "bootargs" variable. However, now you must make
4125 sure that the initrd image is placed in the first
4126 12 MB as well - this can be done with
4128 setenv initrd_high 00c00000
4130 If you set initrd_high to 0xFFFFFFFF, this is an
4131 indication to U-Boot that all addresses are legal
4132 for the Linux kernel, including addresses in flash
4133 memory. In this case U-Boot will NOT COPY the
4134 ramdisk at all. This may be useful to reduce the
4135 boot time on your system, but requires that this
4136 feature is supported by your Linux kernel.
4138 ipaddr - IP address; needed for tftpboot command
4140 loadaddr - Default load address for commands like "bootp",
4141 "rarpboot", "tftpboot", "loadb" or "diskboot"
4143 loads_echo - see CONFIG_LOADS_ECHO
4145 serverip - TFTP server IP address; needed for tftpboot command
4147 bootretry - see CONFIG_BOOT_RETRY_TIME
4149 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4151 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4153 ethprime - controls which interface is used first.
4155 ethact - controls which interface is currently active.
4156 For example you can do the following
4158 => setenv ethact FEC
4159 => ping 192.168.0.1 # traffic sent on FEC
4160 => setenv ethact SCC
4161 => ping 10.0.0.1 # traffic sent on SCC
4163 ethrotate - When set to "no" U-Boot does not go through all
4164 available network interfaces.
4165 It just stays at the currently selected interface.
4167 netretry - When set to "no" each network operation will
4168 either succeed or fail without retrying.
4169 When set to "once" the network operation will
4170 fail when all the available network interfaces
4171 are tried once without success.
4172 Useful on scripts which control the retry operation
4175 npe_ucode - set load address for the NPE microcode
4177 tftpsrcport - If this is set, the value is used for TFTP's
4180 tftpdstport - If this is set, the value is used for TFTP's UDP
4181 destination port instead of the Well Know Port 69.
4183 tftpblocksize - Block size to use for TFTP transfers; if not set,
4184 we use the TFTP server's default block size
4186 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4187 seconds, minimum value is 1000 = 1 second). Defines
4188 when a packet is considered to be lost so it has to
4189 be retransmitted. The default is 5000 = 5 seconds.
4190 Lowering this value may make downloads succeed
4191 faster in networks with high packet loss rates or
4192 with unreliable TFTP servers.
4194 vlan - When set to a value < 4095 the traffic over
4195 Ethernet is encapsulated/received over 802.1q
4198 The following image location variables contain the location of images
4199 used in booting. The "Image" column gives the role of the image and is
4200 not an environment variable name. The other columns are environment
4201 variable names. "File Name" gives the name of the file on a TFTP
4202 server, "RAM Address" gives the location in RAM the image will be
4203 loaded to, and "Flash Location" gives the image's address in NOR
4204 flash or offset in NAND flash.
4206 *Note* - these variables don't have to be defined for all boards, some
4207 boards currenlty use other variables for these purposes, and some
4208 boards use these variables for other purposes.
4210 Image File Name RAM Address Flash Location
4211 ----- --------- ----------- --------------
4212 u-boot u-boot u-boot_addr_r u-boot_addr
4213 Linux kernel bootfile kernel_addr_r kernel_addr
4214 device tree blob fdtfile fdt_addr_r fdt_addr
4215 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4217 The following environment variables may be used and automatically
4218 updated by the network boot commands ("bootp" and "rarpboot"),
4219 depending the information provided by your boot server:
4221 bootfile - see above
4222 dnsip - IP address of your Domain Name Server
4223 dnsip2 - IP address of your secondary Domain Name Server
4224 gatewayip - IP address of the Gateway (Router) to use
4225 hostname - Target hostname
4227 netmask - Subnet Mask
4228 rootpath - Pathname of the root filesystem on the NFS server
4229 serverip - see above
4232 There are two special Environment Variables:
4234 serial# - contains hardware identification information such
4235 as type string and/or serial number
4236 ethaddr - Ethernet address
4238 These variables can be set only once (usually during manufacturing of
4239 the board). U-Boot refuses to delete or overwrite these variables
4240 once they have been set once.
4243 Further special Environment Variables:
4245 ver - Contains the U-Boot version string as printed
4246 with the "version" command. This variable is
4247 readonly (see CONFIG_VERSION_VARIABLE).
4250 Please note that changes to some configuration parameters may take
4251 only effect after the next boot (yes, that's just like Windoze :-).
4254 Callback functions for environment variables:
4255 ---------------------------------------------
4257 For some environment variables, the behavior of u-boot needs to change
4258 when their values are changed. This functionailty allows functions to
4259 be associated with arbitrary variables. On creation, overwrite, or
4260 deletion, the callback will provide the opportunity for some side
4261 effect to happen or for the change to be rejected.
4263 The callbacks are named and associated with a function using the
4264 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4266 These callbacks are associated with variables in one of two ways. The
4267 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4268 in the board configuration to a string that defines a list of
4269 associations. The list must be in the following format:
4271 entry = variable_name[:callback_name]
4274 If the callback name is not specified, then the callback is deleted.
4275 Spaces are also allowed anywhere in the list.
4277 Callbacks can also be associated by defining the ".callbacks" variable
4278 with the same list format above. Any association in ".callbacks" will
4279 override any association in the static list. You can define
4280 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4281 ".callbacks" envirnoment variable in the default or embedded environment.
4284 Command Line Parsing:
4285 =====================
4287 There are two different command line parsers available with U-Boot:
4288 the old "simple" one, and the much more powerful "hush" shell:
4290 Old, simple command line parser:
4291 --------------------------------
4293 - supports environment variables (through setenv / saveenv commands)
4294 - several commands on one line, separated by ';'
4295 - variable substitution using "... ${name} ..." syntax
4296 - special characters ('$', ';') can be escaped by prefixing with '\',
4298 setenv bootcmd bootm \${address}
4299 - You can also escape text by enclosing in single apostrophes, for example:
4300 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4305 - similar to Bourne shell, with control structures like
4306 if...then...else...fi, for...do...done; while...do...done,
4307 until...do...done, ...
4308 - supports environment ("global") variables (through setenv / saveenv
4309 commands) and local shell variables (through standard shell syntax
4310 "name=value"); only environment variables can be used with "run"
4316 (1) If a command line (or an environment variable executed by a "run"
4317 command) contains several commands separated by semicolon, and
4318 one of these commands fails, then the remaining commands will be
4321 (2) If you execute several variables with one call to run (i. e.
4322 calling run with a list of variables as arguments), any failing
4323 command will cause "run" to terminate, i. e. the remaining
4324 variables are not executed.
4326 Note for Redundant Ethernet Interfaces:
4327 =======================================
4329 Some boards come with redundant Ethernet interfaces; U-Boot supports
4330 such configurations and is capable of automatic selection of a
4331 "working" interface when needed. MAC assignment works as follows:
4333 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4334 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4335 "eth1addr" (=>eth1), "eth2addr", ...
4337 If the network interface stores some valid MAC address (for instance
4338 in SROM), this is used as default address if there is NO correspon-
4339 ding setting in the environment; if the corresponding environment
4340 variable is set, this overrides the settings in the card; that means:
4342 o If the SROM has a valid MAC address, and there is no address in the
4343 environment, the SROM's address is used.
4345 o If there is no valid address in the SROM, and a definition in the
4346 environment exists, then the value from the environment variable is
4349 o If both the SROM and the environment contain a MAC address, and
4350 both addresses are the same, this MAC address is used.
4352 o If both the SROM and the environment contain a MAC address, and the
4353 addresses differ, the value from the environment is used and a
4356 o If neither SROM nor the environment contain a MAC address, an error
4359 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4360 will be programmed into hardware as part of the initialization process. This
4361 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4362 The naming convention is as follows:
4363 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4368 U-Boot is capable of booting (and performing other auxiliary operations on)
4369 images in two formats:
4371 New uImage format (FIT)
4372 -----------------------
4374 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4375 to Flattened Device Tree). It allows the use of images with multiple
4376 components (several kernels, ramdisks, etc.), with contents protected by
4377 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4383 Old image format is based on binary files which can be basically anything,
4384 preceded by a special header; see the definitions in include/image.h for
4385 details; basically, the header defines the following image properties:
4387 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4388 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4389 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4390 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4392 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4393 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4394 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4395 * Compression Type (uncompressed, gzip, bzip2)
4401 The header is marked by a special Magic Number, and both the header
4402 and the data portions of the image are secured against corruption by
4409 Although U-Boot should support any OS or standalone application
4410 easily, the main focus has always been on Linux during the design of
4413 U-Boot includes many features that so far have been part of some
4414 special "boot loader" code within the Linux kernel. Also, any
4415 "initrd" images to be used are no longer part of one big Linux image;
4416 instead, kernel and "initrd" are separate images. This implementation
4417 serves several purposes:
4419 - the same features can be used for other OS or standalone
4420 applications (for instance: using compressed images to reduce the
4421 Flash memory footprint)
4423 - it becomes much easier to port new Linux kernel versions because
4424 lots of low-level, hardware dependent stuff are done by U-Boot
4426 - the same Linux kernel image can now be used with different "initrd"
4427 images; of course this also means that different kernel images can
4428 be run with the same "initrd". This makes testing easier (you don't
4429 have to build a new "zImage.initrd" Linux image when you just
4430 change a file in your "initrd"). Also, a field-upgrade of the
4431 software is easier now.
4437 Porting Linux to U-Boot based systems:
4438 ---------------------------------------
4440 U-Boot cannot save you from doing all the necessary modifications to
4441 configure the Linux device drivers for use with your target hardware
4442 (no, we don't intend to provide a full virtual machine interface to
4445 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4447 Just make sure your machine specific header file (for instance
4448 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4449 Information structure as we define in include/asm-<arch>/u-boot.h,
4450 and make sure that your definition of IMAP_ADDR uses the same value
4451 as your U-Boot configuration in CONFIG_SYS_IMMR.
4454 Configuring the Linux kernel:
4455 -----------------------------
4457 No specific requirements for U-Boot. Make sure you have some root
4458 device (initial ramdisk, NFS) for your target system.
4461 Building a Linux Image:
4462 -----------------------
4464 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4465 not used. If you use recent kernel source, a new build target
4466 "uImage" will exist which automatically builds an image usable by
4467 U-Boot. Most older kernels also have support for a "pImage" target,
4468 which was introduced for our predecessor project PPCBoot and uses a
4469 100% compatible format.
4478 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4479 encapsulate a compressed Linux kernel image with header information,
4480 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4482 * build a standard "vmlinux" kernel image (in ELF binary format):
4484 * convert the kernel into a raw binary image:
4486 ${CROSS_COMPILE}-objcopy -O binary \
4487 -R .note -R .comment \
4488 -S vmlinux linux.bin
4490 * compress the binary image:
4494 * package compressed binary image for U-Boot:
4496 mkimage -A ppc -O linux -T kernel -C gzip \
4497 -a 0 -e 0 -n "Linux Kernel Image" \
4498 -d linux.bin.gz uImage
4501 The "mkimage" tool can also be used to create ramdisk images for use
4502 with U-Boot, either separated from the Linux kernel image, or
4503 combined into one file. "mkimage" encapsulates the images with a 64
4504 byte header containing information about target architecture,
4505 operating system, image type, compression method, entry points, time
4506 stamp, CRC32 checksums, etc.
4508 "mkimage" can be called in two ways: to verify existing images and
4509 print the header information, or to build new images.
4511 In the first form (with "-l" option) mkimage lists the information
4512 contained in the header of an existing U-Boot image; this includes
4513 checksum verification:
4515 tools/mkimage -l image
4516 -l ==> list image header information
4518 The second form (with "-d" option) is used to build a U-Boot image
4519 from a "data file" which is used as image payload:
4521 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4522 -n name -d data_file image
4523 -A ==> set architecture to 'arch'
4524 -O ==> set operating system to 'os'
4525 -T ==> set image type to 'type'
4526 -C ==> set compression type 'comp'
4527 -a ==> set load address to 'addr' (hex)
4528 -e ==> set entry point to 'ep' (hex)
4529 -n ==> set image name to 'name'
4530 -d ==> use image data from 'datafile'
4532 Right now, all Linux kernels for PowerPC systems use the same load
4533 address (0x00000000), but the entry point address depends on the
4536 - 2.2.x kernels have the entry point at 0x0000000C,
4537 - 2.3.x and later kernels have the entry point at 0x00000000.
4539 So a typical call to build a U-Boot image would read:
4541 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4542 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4543 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4544 > examples/uImage.TQM850L
4545 Image Name: 2.4.4 kernel for TQM850L
4546 Created: Wed Jul 19 02:34:59 2000
4547 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4548 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4549 Load Address: 0x00000000
4550 Entry Point: 0x00000000
4552 To verify the contents of the image (or check for corruption):
4554 -> tools/mkimage -l examples/uImage.TQM850L
4555 Image Name: 2.4.4 kernel for TQM850L
4556 Created: Wed Jul 19 02:34:59 2000
4557 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4558 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4559 Load Address: 0x00000000
4560 Entry Point: 0x00000000
4562 NOTE: for embedded systems where boot time is critical you can trade
4563 speed for memory and install an UNCOMPRESSED image instead: this
4564 needs more space in Flash, but boots much faster since it does not
4565 need to be uncompressed:
4567 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4568 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4569 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4570 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4571 > examples/uImage.TQM850L-uncompressed
4572 Image Name: 2.4.4 kernel for TQM850L
4573 Created: Wed Jul 19 02:34:59 2000
4574 Image Type: PowerPC Linux Kernel Image (uncompressed)
4575 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4576 Load Address: 0x00000000
4577 Entry Point: 0x00000000
4580 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4581 when your kernel is intended to use an initial ramdisk:
4583 -> tools/mkimage -n 'Simple Ramdisk Image' \
4584 > -A ppc -O linux -T ramdisk -C gzip \
4585 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4586 Image Name: Simple Ramdisk Image
4587 Created: Wed Jan 12 14:01:50 2000
4588 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4589 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4590 Load Address: 0x00000000
4591 Entry Point: 0x00000000
4594 Installing a Linux Image:
4595 -------------------------
4597 To downloading a U-Boot image over the serial (console) interface,
4598 you must convert the image to S-Record format:
4600 objcopy -I binary -O srec examples/image examples/image.srec
4602 The 'objcopy' does not understand the information in the U-Boot
4603 image header, so the resulting S-Record file will be relative to
4604 address 0x00000000. To load it to a given address, you need to
4605 specify the target address as 'offset' parameter with the 'loads'
4608 Example: install the image to address 0x40100000 (which on the
4609 TQM8xxL is in the first Flash bank):
4611 => erase 40100000 401FFFFF
4617 ## Ready for S-Record download ...
4618 ~>examples/image.srec
4619 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4621 15989 15990 15991 15992
4622 [file transfer complete]
4624 ## Start Addr = 0x00000000
4627 You can check the success of the download using the 'iminfo' command;
4628 this includes a checksum verification so you can be sure no data
4629 corruption happened:
4633 ## Checking Image at 40100000 ...
4634 Image Name: 2.2.13 for initrd on TQM850L
4635 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4636 Data Size: 335725 Bytes = 327 kB = 0 MB
4637 Load Address: 00000000
4638 Entry Point: 0000000c
4639 Verifying Checksum ... OK
4645 The "bootm" command is used to boot an application that is stored in
4646 memory (RAM or Flash). In case of a Linux kernel image, the contents
4647 of the "bootargs" environment variable is passed to the kernel as
4648 parameters. You can check and modify this variable using the
4649 "printenv" and "setenv" commands:
4652 => printenv bootargs
4653 bootargs=root=/dev/ram
4655 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4657 => printenv bootargs
4658 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4661 ## Booting Linux kernel at 40020000 ...
4662 Image Name: 2.2.13 for NFS on TQM850L
4663 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4664 Data Size: 381681 Bytes = 372 kB = 0 MB
4665 Load Address: 00000000
4666 Entry Point: 0000000c
4667 Verifying Checksum ... OK
4668 Uncompressing Kernel Image ... OK
4669 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
4670 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4671 time_init: decrementer frequency = 187500000/60
4672 Calibrating delay loop... 49.77 BogoMIPS
4673 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4676 If you want to boot a Linux kernel with initial RAM disk, you pass
4677 the memory addresses of both the kernel and the initrd image (PPBCOOT
4678 format!) to the "bootm" command:
4680 => imi 40100000 40200000
4682 ## Checking Image at 40100000 ...
4683 Image Name: 2.2.13 for initrd on TQM850L
4684 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4685 Data Size: 335725 Bytes = 327 kB = 0 MB
4686 Load Address: 00000000
4687 Entry Point: 0000000c
4688 Verifying Checksum ... OK
4690 ## Checking Image at 40200000 ...
4691 Image Name: Simple Ramdisk Image
4692 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4693 Data Size: 566530 Bytes = 553 kB = 0 MB
4694 Load Address: 00000000
4695 Entry Point: 00000000
4696 Verifying Checksum ... OK
4698 => bootm 40100000 40200000
4699 ## Booting Linux kernel at 40100000 ...
4700 Image Name: 2.2.13 for initrd on TQM850L
4701 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4702 Data Size: 335725 Bytes = 327 kB = 0 MB
4703 Load Address: 00000000
4704 Entry Point: 0000000c
4705 Verifying Checksum ... OK
4706 Uncompressing Kernel Image ... OK
4707 ## Loading RAMDisk Image at 40200000 ...
4708 Image Name: Simple Ramdisk Image
4709 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4710 Data Size: 566530 Bytes = 553 kB = 0 MB
4711 Load Address: 00000000
4712 Entry Point: 00000000
4713 Verifying Checksum ... OK
4714 Loading Ramdisk ... OK
4715 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
4716 Boot arguments: root=/dev/ram
4717 time_init: decrementer frequency = 187500000/60
4718 Calibrating delay loop... 49.77 BogoMIPS
4720 RAMDISK: Compressed image found at block 0
4721 VFS: Mounted root (ext2 filesystem).
4725 Boot Linux and pass a flat device tree:
4728 First, U-Boot must be compiled with the appropriate defines. See the section
4729 titled "Linux Kernel Interface" above for a more in depth explanation. The
4730 following is an example of how to start a kernel and pass an updated
4736 oft=oftrees/mpc8540ads.dtb
4737 => tftp $oftaddr $oft
4738 Speed: 1000, full duplex
4740 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4741 Filename 'oftrees/mpc8540ads.dtb'.
4742 Load address: 0x300000
4745 Bytes transferred = 4106 (100a hex)
4746 => tftp $loadaddr $bootfile
4747 Speed: 1000, full duplex
4749 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4751 Load address: 0x200000
4752 Loading:############
4754 Bytes transferred = 1029407 (fb51f hex)
4759 => bootm $loadaddr - $oftaddr
4760 ## Booting image at 00200000 ...
4761 Image Name: Linux-2.6.17-dirty
4762 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4763 Data Size: 1029343 Bytes = 1005.2 kB
4764 Load Address: 00000000
4765 Entry Point: 00000000
4766 Verifying Checksum ... OK
4767 Uncompressing Kernel Image ... OK
4768 Booting using flat device tree at 0x300000
4769 Using MPC85xx ADS machine description
4770 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4774 More About U-Boot Image Types:
4775 ------------------------------
4777 U-Boot supports the following image types:
4779 "Standalone Programs" are directly runnable in the environment
4780 provided by U-Boot; it is expected that (if they behave
4781 well) you can continue to work in U-Boot after return from
4782 the Standalone Program.
4783 "OS Kernel Images" are usually images of some Embedded OS which
4784 will take over control completely. Usually these programs
4785 will install their own set of exception handlers, device
4786 drivers, set up the MMU, etc. - this means, that you cannot
4787 expect to re-enter U-Boot except by resetting the CPU.
4788 "RAMDisk Images" are more or less just data blocks, and their
4789 parameters (address, size) are passed to an OS kernel that is
4791 "Multi-File Images" contain several images, typically an OS
4792 (Linux) kernel image and one or more data images like
4793 RAMDisks. This construct is useful for instance when you want
4794 to boot over the network using BOOTP etc., where the boot
4795 server provides just a single image file, but you want to get
4796 for instance an OS kernel and a RAMDisk image.
4798 "Multi-File Images" start with a list of image sizes, each
4799 image size (in bytes) specified by an "uint32_t" in network
4800 byte order. This list is terminated by an "(uint32_t)0".
4801 Immediately after the terminating 0 follow the images, one by
4802 one, all aligned on "uint32_t" boundaries (size rounded up to
4803 a multiple of 4 bytes).
4805 "Firmware Images" are binary images containing firmware (like
4806 U-Boot or FPGA images) which usually will be programmed to
4809 "Script files" are command sequences that will be executed by
4810 U-Boot's command interpreter; this feature is especially
4811 useful when you configure U-Boot to use a real shell (hush)
4812 as command interpreter.
4814 Booting the Linux zImage:
4815 -------------------------
4817 On some platforms, it's possible to boot Linux zImage. This is done
4818 using the "bootz" command. The syntax of "bootz" command is the same
4819 as the syntax of "bootm" command.
4821 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4822 kernel with raw initrd images. The syntax is slightly different, the
4823 address of the initrd must be augmented by it's size, in the following
4824 format: "<initrd addres>:<initrd size>".
4830 One of the features of U-Boot is that you can dynamically load and
4831 run "standalone" applications, which can use some resources of
4832 U-Boot like console I/O functions or interrupt services.
4834 Two simple examples are included with the sources:
4839 'examples/hello_world.c' contains a small "Hello World" Demo
4840 application; it is automatically compiled when you build U-Boot.
4841 It's configured to run at address 0x00040004, so you can play with it
4845 ## Ready for S-Record download ...
4846 ~>examples/hello_world.srec
4847 1 2 3 4 5 6 7 8 9 10 11 ...
4848 [file transfer complete]
4850 ## Start Addr = 0x00040004
4852 => go 40004 Hello World! This is a test.
4853 ## Starting application at 0x00040004 ...
4864 Hit any key to exit ...
4866 ## Application terminated, rc = 0x0
4868 Another example, which demonstrates how to register a CPM interrupt
4869 handler with the U-Boot code, can be found in 'examples/timer.c'.
4870 Here, a CPM timer is set up to generate an interrupt every second.
4871 The interrupt service routine is trivial, just printing a '.'
4872 character, but this is just a demo program. The application can be
4873 controlled by the following keys:
4875 ? - print current values og the CPM Timer registers
4876 b - enable interrupts and start timer
4877 e - stop timer and disable interrupts
4878 q - quit application
4881 ## Ready for S-Record download ...
4882 ~>examples/timer.srec
4883 1 2 3 4 5 6 7 8 9 10 11 ...
4884 [file transfer complete]
4886 ## Start Addr = 0x00040004
4889 ## Starting application at 0x00040004 ...
4892 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4895 [q, b, e, ?] Set interval 1000000 us
4898 [q, b, e, ?] ........
4899 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4902 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4905 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4908 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4910 [q, b, e, ?] ...Stopping timer
4912 [q, b, e, ?] ## Application terminated, rc = 0x0
4918 Over time, many people have reported problems when trying to use the
4919 "minicom" terminal emulation program for serial download. I (wd)
4920 consider minicom to be broken, and recommend not to use it. Under
4921 Unix, I recommend to use C-Kermit for general purpose use (and
4922 especially for kermit binary protocol download ("loadb" command), and
4923 use "cu" for S-Record download ("loads" command). See
4924 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4925 for help with kermit.
4928 Nevertheless, if you absolutely want to use it try adding this
4929 configuration to your "File transfer protocols" section:
4931 Name Program Name U/D FullScr IO-Red. Multi
4932 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4933 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4939 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4940 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4942 Building requires a cross environment; it is known to work on
4943 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4944 need gmake since the Makefiles are not compatible with BSD make).
4945 Note that the cross-powerpc package does not install include files;
4946 attempting to build U-Boot will fail because <machine/ansi.h> is
4947 missing. This file has to be installed and patched manually:
4949 # cd /usr/pkg/cross/powerpc-netbsd/include
4951 # ln -s powerpc machine
4952 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4953 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4955 Native builds *don't* work due to incompatibilities between native
4956 and U-Boot include files.
4958 Booting assumes that (the first part of) the image booted is a
4959 stage-2 loader which in turn loads and then invokes the kernel
4960 proper. Loader sources will eventually appear in the NetBSD source
4961 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4962 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4965 Implementation Internals:
4966 =========================
4968 The following is not intended to be a complete description of every
4969 implementation detail. However, it should help to understand the
4970 inner workings of U-Boot and make it easier to port it to custom
4974 Initial Stack, Global Data:
4975 ---------------------------
4977 The implementation of U-Boot is complicated by the fact that U-Boot
4978 starts running out of ROM (flash memory), usually without access to
4979 system RAM (because the memory controller is not initialized yet).
4980 This means that we don't have writable Data or BSS segments, and BSS
4981 is not initialized as zero. To be able to get a C environment working
4982 at all, we have to allocate at least a minimal stack. Implementation
4983 options for this are defined and restricted by the CPU used: Some CPU
4984 models provide on-chip memory (like the IMMR area on MPC8xx and
4985 MPC826x processors), on others (parts of) the data cache can be
4986 locked as (mis-) used as memory, etc.
4988 Chris Hallinan posted a good summary of these issues to the
4989 U-Boot mailing list:
4991 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4992 From: "Chris Hallinan" <clh@net1plus.com>
4993 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4996 Correct me if I'm wrong, folks, but the way I understand it
4997 is this: Using DCACHE as initial RAM for Stack, etc, does not
4998 require any physical RAM backing up the cache. The cleverness
4999 is that the cache is being used as a temporary supply of
5000 necessary storage before the SDRAM controller is setup. It's
5001 beyond the scope of this list to explain the details, but you
5002 can see how this works by studying the cache architecture and
5003 operation in the architecture and processor-specific manuals.
5005 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5006 is another option for the system designer to use as an
5007 initial stack/RAM area prior to SDRAM being available. Either
5008 option should work for you. Using CS 4 should be fine if your
5009 board designers haven't used it for something that would
5010 cause you grief during the initial boot! It is frequently not
5013 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5014 with your processor/board/system design. The default value
5015 you will find in any recent u-boot distribution in
5016 walnut.h should work for you. I'd set it to a value larger
5017 than your SDRAM module. If you have a 64MB SDRAM module, set
5018 it above 400_0000. Just make sure your board has no resources
5019 that are supposed to respond to that address! That code in
5020 start.S has been around a while and should work as is when
5021 you get the config right.
5026 It is essential to remember this, since it has some impact on the C
5027 code for the initialization procedures:
5029 * Initialized global data (data segment) is read-only. Do not attempt
5032 * Do not use any uninitialized global data (or implicitely initialized
5033 as zero data - BSS segment) at all - this is undefined, initiali-
5034 zation is performed later (when relocating to RAM).
5036 * Stack space is very limited. Avoid big data buffers or things like
5039 Having only the stack as writable memory limits means we cannot use
5040 normal global data to share information beween the code. But it
5041 turned out that the implementation of U-Boot can be greatly
5042 simplified by making a global data structure (gd_t) available to all
5043 functions. We could pass a pointer to this data as argument to _all_
5044 functions, but this would bloat the code. Instead we use a feature of
5045 the GCC compiler (Global Register Variables) to share the data: we
5046 place a pointer (gd) to the global data into a register which we
5047 reserve for this purpose.
5049 When choosing a register for such a purpose we are restricted by the
5050 relevant (E)ABI specifications for the current architecture, and by
5051 GCC's implementation.
5053 For PowerPC, the following registers have specific use:
5055 R2: reserved for system use
5056 R3-R4: parameter passing and return values
5057 R5-R10: parameter passing
5058 R13: small data area pointer
5062 (U-Boot also uses R12 as internal GOT pointer. r12
5063 is a volatile register so r12 needs to be reset when
5064 going back and forth between asm and C)
5066 ==> U-Boot will use R2 to hold a pointer to the global data
5068 Note: on PPC, we could use a static initializer (since the
5069 address of the global data structure is known at compile time),
5070 but it turned out that reserving a register results in somewhat
5071 smaller code - although the code savings are not that big (on
5072 average for all boards 752 bytes for the whole U-Boot image,
5073 624 text + 127 data).
5075 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5076 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5078 ==> U-Boot will use P3 to hold a pointer to the global data
5080 On ARM, the following registers are used:
5082 R0: function argument word/integer result
5083 R1-R3: function argument word
5085 R10: stack limit (used only if stack checking if enabled)
5086 R11: argument (frame) pointer
5087 R12: temporary workspace
5090 R15: program counter
5092 ==> U-Boot will use R8 to hold a pointer to the global data
5094 On Nios II, the ABI is documented here:
5095 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5097 ==> U-Boot will use gp to hold a pointer to the global data
5099 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5100 to access small data sections, so gp is free.
5102 On NDS32, the following registers are used:
5104 R0-R1: argument/return
5106 R15: temporary register for assembler
5107 R16: trampoline register
5108 R28: frame pointer (FP)
5109 R29: global pointer (GP)
5110 R30: link register (LP)
5111 R31: stack pointer (SP)
5112 PC: program counter (PC)
5114 ==> U-Boot will use R10 to hold a pointer to the global data
5116 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5117 or current versions of GCC may "optimize" the code too much.
5122 U-Boot runs in system state and uses physical addresses, i.e. the
5123 MMU is not used either for address mapping nor for memory protection.
5125 The available memory is mapped to fixed addresses using the memory
5126 controller. In this process, a contiguous block is formed for each
5127 memory type (Flash, SDRAM, SRAM), even when it consists of several
5128 physical memory banks.
5130 U-Boot is installed in the first 128 kB of the first Flash bank (on
5131 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5132 booting and sizing and initializing DRAM, the code relocates itself
5133 to the upper end of DRAM. Immediately below the U-Boot code some
5134 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5135 configuration setting]. Below that, a structure with global Board
5136 Info data is placed, followed by the stack (growing downward).
5138 Additionally, some exception handler code is copied to the low 8 kB
5139 of DRAM (0x00000000 ... 0x00001FFF).
5141 So a typical memory configuration with 16 MB of DRAM could look like
5144 0x0000 0000 Exception Vector code
5147 0x0000 2000 Free for Application Use
5153 0x00FB FF20 Monitor Stack (Growing downward)
5154 0x00FB FFAC Board Info Data and permanent copy of global data
5155 0x00FC 0000 Malloc Arena
5158 0x00FE 0000 RAM Copy of Monitor Code
5159 ... eventually: LCD or video framebuffer
5160 ... eventually: pRAM (Protected RAM - unchanged by reset)
5161 0x00FF FFFF [End of RAM]
5164 System Initialization:
5165 ----------------------
5167 In the reset configuration, U-Boot starts at the reset entry point
5168 (on most PowerPC systems at address 0x00000100). Because of the reset
5169 configuration for CS0# this is a mirror of the onboard Flash memory.
5170 To be able to re-map memory U-Boot then jumps to its link address.
5171 To be able to implement the initialization code in C, a (small!)
5172 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5173 which provide such a feature like MPC8xx or MPC8260), or in a locked
5174 part of the data cache. After that, U-Boot initializes the CPU core,
5175 the caches and the SIU.
5177 Next, all (potentially) available memory banks are mapped using a
5178 preliminary mapping. For example, we put them on 512 MB boundaries
5179 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5180 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5181 programmed for SDRAM access. Using the temporary configuration, a
5182 simple memory test is run that determines the size of the SDRAM
5185 When there is more than one SDRAM bank, and the banks are of
5186 different size, the largest is mapped first. For equal size, the first
5187 bank (CS2#) is mapped first. The first mapping is always for address
5188 0x00000000, with any additional banks following immediately to create
5189 contiguous memory starting from 0.
5191 Then, the monitor installs itself at the upper end of the SDRAM area
5192 and allocates memory for use by malloc() and for the global Board
5193 Info data; also, the exception vector code is copied to the low RAM
5194 pages, and the final stack is set up.
5196 Only after this relocation will you have a "normal" C environment;
5197 until that you are restricted in several ways, mostly because you are
5198 running from ROM, and because the code will have to be relocated to a
5202 U-Boot Porting Guide:
5203 ----------------------
5205 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5209 int main(int argc, char *argv[])
5211 sighandler_t no_more_time;
5213 signal(SIGALRM, no_more_time);
5214 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5216 if (available_money > available_manpower) {
5217 Pay consultant to port U-Boot;
5221 Download latest U-Boot source;
5223 Subscribe to u-boot mailing list;
5226 email("Hi, I am new to U-Boot, how do I get started?");
5229 Read the README file in the top level directory;
5230 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5231 Read applicable doc/*.README;
5232 Read the source, Luke;
5233 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5236 if (available_money > toLocalCurrency ($2500))
5239 Add a lot of aggravation and time;
5241 if (a similar board exists) { /* hopefully... */
5242 cp -a board/<similar> board/<myboard>
5243 cp include/configs/<similar>.h include/configs/<myboard>.h
5245 Create your own board support subdirectory;
5246 Create your own board include/configs/<myboard>.h file;
5248 Edit new board/<myboard> files
5249 Edit new include/configs/<myboard>.h
5254 Add / modify source code;
5258 email("Hi, I am having problems...");
5260 Send patch file to the U-Boot email list;
5261 if (reasonable critiques)
5262 Incorporate improvements from email list code review;
5264 Defend code as written;
5270 void no_more_time (int sig)
5279 All contributions to U-Boot should conform to the Linux kernel
5280 coding style; see the file "Documentation/CodingStyle" and the script
5281 "scripts/Lindent" in your Linux kernel source directory.
5283 Source files originating from a different project (for example the
5284 MTD subsystem) are generally exempt from these guidelines and are not
5285 reformated to ease subsequent migration to newer versions of those
5288 Please note that U-Boot is implemented in C (and to some small parts in
5289 Assembler); no C++ is used, so please do not use C++ style comments (//)
5292 Please also stick to the following formatting rules:
5293 - remove any trailing white space
5294 - use TAB characters for indentation and vertical alignment, not spaces
5295 - make sure NOT to use DOS '\r\n' line feeds
5296 - do not add more than 2 consecutive empty lines to source files
5297 - do not add trailing empty lines to source files
5299 Submissions which do not conform to the standards may be returned
5300 with a request to reformat the changes.
5306 Since the number of patches for U-Boot is growing, we need to
5307 establish some rules. Submissions which do not conform to these rules
5308 may be rejected, even when they contain important and valuable stuff.
5310 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5312 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5313 see http://lists.denx.de/mailman/listinfo/u-boot
5315 When you send a patch, please include the following information with
5318 * For bug fixes: a description of the bug and how your patch fixes
5319 this bug. Please try to include a way of demonstrating that the
5320 patch actually fixes something.
5322 * For new features: a description of the feature and your
5325 * A CHANGELOG entry as plaintext (separate from the patch)
5327 * For major contributions, your entry to the CREDITS file
5329 * When you add support for a new board, don't forget to add this
5330 board to the MAINTAINERS file, too.
5332 * If your patch adds new configuration options, don't forget to
5333 document these in the README file.
5335 * The patch itself. If you are using git (which is *strongly*
5336 recommended) you can easily generate the patch using the
5337 "git format-patch". If you then use "git send-email" to send it to
5338 the U-Boot mailing list, you will avoid most of the common problems
5339 with some other mail clients.
5341 If you cannot use git, use "diff -purN OLD NEW". If your version of
5342 diff does not support these options, then get the latest version of
5345 The current directory when running this command shall be the parent
5346 directory of the U-Boot source tree (i. e. please make sure that
5347 your patch includes sufficient directory information for the
5350 We prefer patches as plain text. MIME attachments are discouraged,
5351 and compressed attachments must not be used.
5353 * If one logical set of modifications affects or creates several
5354 files, all these changes shall be submitted in a SINGLE patch file.
5356 * Changesets that contain different, unrelated modifications shall be
5357 submitted as SEPARATE patches, one patch per changeset.
5362 * Before sending the patch, run the MAKEALL script on your patched
5363 source tree and make sure that no errors or warnings are reported
5364 for any of the boards.
5366 * Keep your modifications to the necessary minimum: A patch
5367 containing several unrelated changes or arbitrary reformats will be
5368 returned with a request to re-formatting / split it.
5370 * If you modify existing code, make sure that your new code does not
5371 add to the memory footprint of the code ;-) Small is beautiful!
5372 When adding new features, these should compile conditionally only
5373 (using #ifdef), and the resulting code with the new feature
5374 disabled must not need more memory than the old code without your
5377 * Remember that there is a size limit of 100 kB per message on the
5378 u-boot mailing list. Bigger patches will be moderated. If they are
5379 reasonable and not too big, they will be acknowledged. But patches
5380 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob