2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 - Linux Kernel Interface:
491 U-Boot stores all clock information in Hz
492 internally. For binary compatibility with older Linux
493 kernels (which expect the clocks passed in the
494 bd_info data to be in MHz) the environment variable
495 "clocks_in_mhz" can be defined so that U-Boot
496 converts clock data to MHZ before passing it to the
498 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
499 "clocks_in_mhz=1" is automatically included in the
502 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
504 When transferring memsize parameter to linux, some versions
505 expect it to be in bytes, others in MB.
506 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
510 New kernel versions are expecting firmware settings to be
511 passed using flattened device trees (based on open firmware
515 * New libfdt-based support
516 * Adds the "fdt" command
517 * The bootm command automatically updates the fdt
519 OF_CPU - The proper name of the cpus node (only required for
520 MPC512X and MPC5xxx based boards).
521 OF_SOC - The proper name of the soc node (only required for
522 MPC512X and MPC5xxx based boards).
523 OF_TBCLK - The timebase frequency.
524 OF_STDOUT_PATH - The path to the console device
526 boards with QUICC Engines require OF_QE to set UCC MAC
529 CONFIG_OF_BOARD_SETUP
531 Board code has addition modification that it wants to make
532 to the flat device tree before handing it off to the kernel
536 This define fills in the correct boot CPU in the boot
537 param header, the default value is zero if undefined.
541 U-Boot can detect if an IDE device is present or not.
542 If not, and this new config option is activated, U-Boot
543 removes the ATA node from the DTS before booting Linux,
544 so the Linux IDE driver does not probe the device and
545 crash. This is needed for buggy hardware (uc101) where
546 no pull down resistor is connected to the signal IDE5V_DD7.
548 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
550 This setting is mandatory for all boards that have only one
551 machine type and must be used to specify the machine type
552 number as it appears in the ARM machine registry
553 (see http://www.arm.linux.org.uk/developer/machines/).
554 Only boards that have multiple machine types supported
555 in a single configuration file and the machine type is
556 runtime discoverable, do not have to use this setting.
558 - vxWorks boot parameters:
560 bootvx constructs a valid bootline using the following
561 environments variables: bootfile, ipaddr, serverip, hostname.
562 It loads the vxWorks image pointed bootfile.
564 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
565 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
566 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
567 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
569 CONFIG_SYS_VXWORKS_ADD_PARAMS
571 Add it at the end of the bootline. E.g "u=username pw=secret"
573 Note: If a "bootargs" environment is defined, it will overwride
574 the defaults discussed just above.
576 - Cache Configuration:
577 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
578 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
579 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
581 - Cache Configuration for ARM:
582 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
584 CONFIG_SYS_PL310_BASE - Physical base address of PL310
585 controller register space
590 Define this if you want support for Amba PrimeCell PL010 UARTs.
594 Define this if you want support for Amba PrimeCell PL011 UARTs.
598 If you have Amba PrimeCell PL011 UARTs, set this variable to
599 the clock speed of the UARTs.
603 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
604 define this to a list of base addresses for each (supported)
605 port. See e.g. include/configs/versatile.h
607 CONFIG_PL011_SERIAL_RLCR
609 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
610 have separate receive and transmit line control registers. Set
611 this variable to initialize the extra register.
613 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
615 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
616 boot loader that has already initialized the UART. Define this
617 variable to flush the UART at init time.
619 CONFIG_SYS_NS16550_BROKEN_TEMT
621 16550 UART set the Transmitter Empty (TEMT) Bit when all output
622 has finished and the transmitter is totally empty. U-Boot waits
623 for this bit to be set to initialize the serial console. On some
624 broken platforms this bit is not set in SPL making U-Boot to
625 hang while waiting for TEMT. Define this option to avoid it.
629 Depending on board, define exactly one serial port
630 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
631 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
632 console by defining CONFIG_8xx_CONS_NONE
634 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
635 port routines must be defined elsewhere
636 (i.e. serial_init(), serial_getc(), ...)
639 Enables console device for a color framebuffer. Needs following
640 defines (cf. smiLynxEM, i8042)
641 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
643 VIDEO_HW_RECTFILL graphic chip supports
646 VIDEO_HW_BITBLT graphic chip supports
647 bit-blit (cf. smiLynxEM)
648 VIDEO_VISIBLE_COLS visible pixel columns
650 VIDEO_VISIBLE_ROWS visible pixel rows
651 VIDEO_PIXEL_SIZE bytes per pixel
652 VIDEO_DATA_FORMAT graphic data format
653 (0-5, cf. cfb_console.c)
654 VIDEO_FB_ADRS framebuffer address
655 VIDEO_KBD_INIT_FCT keyboard int fct
656 (i.e. i8042_kbd_init())
657 VIDEO_TSTC_FCT test char fct
659 VIDEO_GETC_FCT get char fct
661 CONFIG_CONSOLE_CURSOR cursor drawing on/off
662 (requires blink timer
664 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
665 CONFIG_CONSOLE_TIME display time/date info in
667 (requires CONFIG_CMD_DATE)
668 CONFIG_VIDEO_LOGO display Linux logo in
670 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
671 linux_logo.h for logo.
672 Requires CONFIG_VIDEO_LOGO
673 CONFIG_CONSOLE_EXTRA_INFO
674 additional board info beside
677 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
678 a limited number of ANSI escape sequences (cursor control,
679 erase functions and limited graphics rendition control).
681 When CONFIG_CFB_CONSOLE is defined, video console is
682 default i/o. Serial console can be forced with
683 environment 'console=serial'.
685 When CONFIG_SILENT_CONSOLE is defined, all console
686 messages (by U-Boot and Linux!) can be silenced with
687 the "silent" environment variable. See
688 doc/README.silent for more information.
691 CONFIG_BAUDRATE - in bps
692 Select one of the baudrates listed in
693 CONFIG_SYS_BAUDRATE_TABLE, see below.
694 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
696 - Console Rx buffer length
697 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
698 the maximum receive buffer length for the SMC.
699 This option is actual only for 82xx and 8xx possible.
700 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
701 must be defined, to setup the maximum idle timeout for
704 - Pre-Console Buffer:
705 Prior to the console being initialised (i.e. serial UART
706 initialised etc) all console output is silently discarded.
707 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
708 buffer any console messages prior to the console being
709 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
710 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
711 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
712 bytes are output before the console is initialised, the
713 earlier bytes are discarded.
715 'Sane' compilers will generate smaller code if
716 CONFIG_PRE_CON_BUF_SZ is a power of 2
718 - Safe printf() functions
719 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
720 the printf() functions. These are defined in
721 include/vsprintf.h and include snprintf(), vsnprintf() and
722 so on. Code size increase is approximately 300-500 bytes.
723 If this option is not given then these functions will
724 silently discard their buffer size argument - this means
725 you are not getting any overflow checking in this case.
727 - Boot Delay: CONFIG_BOOTDELAY - in seconds
728 Delay before automatically booting the default image;
729 set to -1 to disable autoboot.
730 set to -2 to autoboot with no delay and not check for abort
731 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
733 See doc/README.autoboot for these options that
734 work with CONFIG_BOOTDELAY. None are required.
735 CONFIG_BOOT_RETRY_TIME
736 CONFIG_BOOT_RETRY_MIN
737 CONFIG_AUTOBOOT_KEYED
738 CONFIG_AUTOBOOT_PROMPT
739 CONFIG_AUTOBOOT_DELAY_STR
740 CONFIG_AUTOBOOT_STOP_STR
741 CONFIG_AUTOBOOT_DELAY_STR2
742 CONFIG_AUTOBOOT_STOP_STR2
743 CONFIG_ZERO_BOOTDELAY_CHECK
744 CONFIG_RESET_TO_RETRY
748 Only needed when CONFIG_BOOTDELAY is enabled;
749 define a command string that is automatically executed
750 when no character is read on the console interface
751 within "Boot Delay" after reset.
754 This can be used to pass arguments to the bootm
755 command. The value of CONFIG_BOOTARGS goes into the
756 environment value "bootargs".
758 CONFIG_RAMBOOT and CONFIG_NFSBOOT
759 The value of these goes into the environment as
760 "ramboot" and "nfsboot" respectively, and can be used
761 as a convenience, when switching between booting from
767 When this option is #defined, the existence of the
768 environment variable "preboot" will be checked
769 immediately before starting the CONFIG_BOOTDELAY
770 countdown and/or running the auto-boot command resp.
771 entering interactive mode.
773 This feature is especially useful when "preboot" is
774 automatically generated or modified. For an example
775 see the LWMON board specific code: here "preboot" is
776 modified when the user holds down a certain
777 combination of keys on the (special) keyboard when
780 - Serial Download Echo Mode:
782 If defined to 1, all characters received during a
783 serial download (using the "loads" command) are
784 echoed back. This might be needed by some terminal
785 emulations (like "cu"), but may as well just take
786 time on others. This setting #define's the initial
787 value of the "loads_echo" environment variable.
789 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
791 Select one of the baudrates listed in
792 CONFIG_SYS_BAUDRATE_TABLE, see below.
795 Monitor commands can be included or excluded
796 from the build by using the #include files
797 <config_cmd_all.h> and #undef'ing unwanted
798 commands, or using <config_cmd_default.h>
799 and augmenting with additional #define's
802 The default command configuration includes all commands
803 except those marked below with a "*".
805 CONFIG_CMD_ASKENV * ask for env variable
806 CONFIG_CMD_BDI bdinfo
807 CONFIG_CMD_BEDBUG * Include BedBug Debugger
808 CONFIG_CMD_BMP * BMP support
809 CONFIG_CMD_BSP * Board specific commands
810 CONFIG_CMD_BOOTD bootd
811 CONFIG_CMD_CACHE * icache, dcache
812 CONFIG_CMD_CONSOLE coninfo
813 CONFIG_CMD_CRC32 * crc32
814 CONFIG_CMD_DATE * support for RTC, date/time...
815 CONFIG_CMD_DHCP * DHCP support
816 CONFIG_CMD_DIAG * Diagnostics
817 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
818 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
819 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
820 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
821 CONFIG_CMD_DTT * Digital Therm and Thermostat
822 CONFIG_CMD_ECHO echo arguments
823 CONFIG_CMD_EDITENV edit env variable
824 CONFIG_CMD_EEPROM * EEPROM read/write support
825 CONFIG_CMD_ELF * bootelf, bootvx
826 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
827 CONFIG_CMD_ENV_FLAGS * display details about env flags
828 CONFIG_CMD_EXPORTENV * export the environment
829 CONFIG_CMD_EXT2 * ext2 command support
830 CONFIG_CMD_EXT4 * ext4 command support
831 CONFIG_CMD_SAVEENV saveenv
832 CONFIG_CMD_FDC * Floppy Disk Support
833 CONFIG_CMD_FAT * FAT command support
834 CONFIG_CMD_FDOS * Dos diskette Support
835 CONFIG_CMD_FLASH flinfo, erase, protect
836 CONFIG_CMD_FPGA FPGA device initialization support
837 CONFIG_CMD_GETTIME * Get time since boot
838 CONFIG_CMD_GO * the 'go' command (exec code)
839 CONFIG_CMD_GREPENV * search environment
840 CONFIG_CMD_HASH * calculate hash / digest
841 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
842 CONFIG_CMD_I2C * I2C serial bus support
843 CONFIG_CMD_IDE * IDE harddisk support
844 CONFIG_CMD_IMI iminfo
845 CONFIG_CMD_IMLS List all images found in NOR flash
846 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
847 CONFIG_CMD_IMMAP * IMMR dump support
848 CONFIG_CMD_IMPORTENV * import an environment
849 CONFIG_CMD_INI * import data from an ini file into the env
850 CONFIG_CMD_IRQ * irqinfo
851 CONFIG_CMD_ITEST Integer/string test of 2 values
852 CONFIG_CMD_JFFS2 * JFFS2 Support
853 CONFIG_CMD_KGDB * kgdb
854 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
855 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
857 CONFIG_CMD_LOADB loadb
858 CONFIG_CMD_LOADS loads
859 CONFIG_CMD_MD5SUM print md5 message digest
860 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
861 CONFIG_CMD_MEMINFO * Display detailed memory information
862 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
864 CONFIG_CMD_MISC Misc functions like sleep etc
865 CONFIG_CMD_MMC * MMC memory mapped support
866 CONFIG_CMD_MII * MII utility commands
867 CONFIG_CMD_MTDPARTS * MTD partition support
868 CONFIG_CMD_NAND * NAND support
869 CONFIG_CMD_NET bootp, tftpboot, rarpboot
870 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
871 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
872 CONFIG_CMD_PCI * pciinfo
873 CONFIG_CMD_PCMCIA * PCMCIA support
874 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
876 CONFIG_CMD_PORTIO * Port I/O
877 CONFIG_CMD_READ * Read raw data from partition
878 CONFIG_CMD_REGINFO * Register dump
879 CONFIG_CMD_RUN run command in env variable
880 CONFIG_CMD_SAVES * save S record dump
881 CONFIG_CMD_SCSI * SCSI Support
882 CONFIG_CMD_SDRAM * print SDRAM configuration information
883 (requires CONFIG_CMD_I2C)
884 CONFIG_CMD_SETGETDCR Support for DCR Register access
886 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
887 CONFIG_CMD_SHA1SUM print sha1 memory digest
888 (requires CONFIG_CMD_MEMORY)
889 CONFIG_CMD_SOURCE "source" command Support
890 CONFIG_CMD_SPI * SPI serial bus support
891 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
892 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
893 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
894 CONFIG_CMD_TIMER * access to the system tick timer
895 CONFIG_CMD_USB * USB support
896 CONFIG_CMD_CDP * Cisco Discover Protocol support
897 CONFIG_CMD_MFSL * Microblaze FSL support
900 EXAMPLE: If you want all functions except of network
901 support you can write:
903 #include "config_cmd_all.h"
904 #undef CONFIG_CMD_NET
907 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
909 Note: Don't enable the "icache" and "dcache" commands
910 (configuration option CONFIG_CMD_CACHE) unless you know
911 what you (and your U-Boot users) are doing. Data
912 cache cannot be enabled on systems like the 8xx or
913 8260 (where accesses to the IMMR region must be
914 uncached), and it cannot be disabled on all other
915 systems where we (mis-) use the data cache to hold an
916 initial stack and some data.
919 XXX - this list needs to get updated!
923 If this variable is defined, U-Boot will use a device tree
924 to configure its devices, instead of relying on statically
925 compiled #defines in the board file. This option is
926 experimental and only available on a few boards. The device
927 tree is available in the global data as gd->fdt_blob.
929 U-Boot needs to get its device tree from somewhere. This can
930 be done using one of the two options below:
933 If this variable is defined, U-Boot will embed a device tree
934 binary in its image. This device tree file should be in the
935 board directory and called <soc>-<board>.dts. The binary file
936 is then picked up in board_init_f() and made available through
937 the global data structure as gd->blob.
940 If this variable is defined, U-Boot will build a device tree
941 binary. It will be called u-boot.dtb. Architecture-specific
942 code will locate it at run-time. Generally this works by:
944 cat u-boot.bin u-boot.dtb >image.bin
946 and in fact, U-Boot does this for you, creating a file called
947 u-boot-dtb.bin which is useful in the common case. You can
948 still use the individual files if you need something more
953 If this variable is defined, it enables watchdog
954 support for the SoC. There must be support in the SoC
955 specific code for a watchdog. For the 8xx and 8260
956 CPUs, the SIU Watchdog feature is enabled in the SYPCR
957 register. When supported for a specific SoC is
958 available, then no further board specific code should
962 When using a watchdog circuitry external to the used
963 SoC, then define this variable and provide board
964 specific code for the "hw_watchdog_reset" function.
967 CONFIG_VERSION_VARIABLE
968 If this variable is defined, an environment variable
969 named "ver" is created by U-Boot showing the U-Boot
970 version as printed by the "version" command.
971 Any change to this variable will be reverted at the
976 When CONFIG_CMD_DATE is selected, the type of the RTC
977 has to be selected, too. Define exactly one of the
980 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
981 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
982 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
983 CONFIG_RTC_MC146818 - use MC146818 RTC
984 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
985 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
986 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
987 CONFIG_RTC_DS164x - use Dallas DS164x RTC
988 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
989 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
990 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
991 CONFIG_SYS_RV3029_TCR - enable trickle charger on
994 Note that if the RTC uses I2C, then the I2C interface
995 must also be configured. See I2C Support, below.
998 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
999 CONFIG_PCA953X_INFO - enable pca953x info command
1001 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1002 chip-ngpio pairs that tell the PCA953X driver the number of
1003 pins supported by a particular chip.
1005 Note that if the GPIO device uses I2C, then the I2C interface
1006 must also be configured. See I2C Support, below.
1008 - Timestamp Support:
1010 When CONFIG_TIMESTAMP is selected, the timestamp
1011 (date and time) of an image is printed by image
1012 commands like bootm or iminfo. This option is
1013 automatically enabled when you select CONFIG_CMD_DATE .
1015 - Partition Labels (disklabels) Supported:
1016 Zero or more of the following:
1017 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1018 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1019 Intel architecture, USB sticks, etc.
1020 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1021 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1022 bootloader. Note 2TB partition limit; see
1024 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1026 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1027 CONFIG_CMD_SCSI) you must configure support for at
1028 least one non-MTD partition type as well.
1031 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1032 board configurations files but used nowhere!
1034 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1035 be performed by calling the function
1036 ide_set_reset(int reset)
1037 which has to be defined in a board specific file
1042 Set this to enable ATAPI support.
1047 Set this to enable support for disks larger than 137GB
1048 Also look at CONFIG_SYS_64BIT_LBA.
1049 Whithout these , LBA48 support uses 32bit variables and will 'only'
1050 support disks up to 2.1TB.
1052 CONFIG_SYS_64BIT_LBA:
1053 When enabled, makes the IDE subsystem use 64bit sector addresses.
1057 At the moment only there is only support for the
1058 SYM53C8XX SCSI controller; define
1059 CONFIG_SCSI_SYM53C8XX to enable it.
1061 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1062 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1063 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1064 maximum numbers of LUNs, SCSI ID's and target
1066 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1068 The environment variable 'scsidevs' is set to the number of
1069 SCSI devices found during the last scan.
1071 - NETWORK Support (PCI):
1073 Support for Intel 8254x/8257x gigabit chips.
1076 Utility code for direct access to the SPI bus on Intel 8257x.
1077 This does not do anything useful unless you set at least one
1078 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1080 CONFIG_E1000_SPI_GENERIC
1081 Allow generic access to the SPI bus on the Intel 8257x, for
1082 example with the "sspi" command.
1085 Management command for E1000 devices. When used on devices
1086 with SPI support you can reprogram the EEPROM from U-Boot.
1088 CONFIG_E1000_FALLBACK_MAC
1089 default MAC for empty EEPROM after production.
1092 Support for Intel 82557/82559/82559ER chips.
1093 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1094 write routine for first time initialisation.
1097 Support for Digital 2114x chips.
1098 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1099 modem chip initialisation (KS8761/QS6611).
1102 Support for National dp83815 chips.
1105 Support for National dp8382[01] gigabit chips.
1107 - NETWORK Support (other):
1109 CONFIG_DRIVER_AT91EMAC
1110 Support for AT91RM9200 EMAC.
1113 Define this to use reduced MII inteface
1115 CONFIG_DRIVER_AT91EMAC_QUIET
1116 If this defined, the driver is quiet.
1117 The driver doen't show link status messages.
1119 CONFIG_CALXEDA_XGMAC
1120 Support for the Calxeda XGMAC device
1123 Support for SMSC's LAN91C96 chips.
1125 CONFIG_LAN91C96_BASE
1126 Define this to hold the physical address
1127 of the LAN91C96's I/O space
1129 CONFIG_LAN91C96_USE_32_BIT
1130 Define this to enable 32 bit addressing
1133 Support for SMSC's LAN91C111 chip
1135 CONFIG_SMC91111_BASE
1136 Define this to hold the physical address
1137 of the device (I/O space)
1139 CONFIG_SMC_USE_32_BIT
1140 Define this if data bus is 32 bits
1142 CONFIG_SMC_USE_IOFUNCS
1143 Define this to use i/o functions instead of macros
1144 (some hardware wont work with macros)
1146 CONFIG_DRIVER_TI_EMAC
1147 Support for davinci emac
1149 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1150 Define this if you have more then 3 PHYs.
1153 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1155 CONFIG_FTGMAC100_EGIGA
1156 Define this to use GE link update with gigabit PHY.
1157 Define this if FTGMAC100 is connected to gigabit PHY.
1158 If your system has 10/100 PHY only, it might not occur
1159 wrong behavior. Because PHY usually return timeout or
1160 useless data when polling gigabit status and gigabit
1161 control registers. This behavior won't affect the
1162 correctnessof 10/100 link speed update.
1165 Support for SMSC's LAN911x and LAN921x chips
1168 Define this to hold the physical address
1169 of the device (I/O space)
1171 CONFIG_SMC911X_32_BIT
1172 Define this if data bus is 32 bits
1174 CONFIG_SMC911X_16_BIT
1175 Define this if data bus is 16 bits. If your processor
1176 automatically converts one 32 bit word to two 16 bit
1177 words you may also try CONFIG_SMC911X_32_BIT.
1180 Support for Renesas on-chip Ethernet controller
1182 CONFIG_SH_ETHER_USE_PORT
1183 Define the number of ports to be used
1185 CONFIG_SH_ETHER_PHY_ADDR
1186 Define the ETH PHY's address
1188 CONFIG_SH_ETHER_CACHE_WRITEBACK
1189 If this option is set, the driver enables cache flush.
1192 CONFIG_GENERIC_LPC_TPM
1193 Support for generic parallel port TPM devices. Only one device
1194 per system is supported at this time.
1196 CONFIG_TPM_TIS_BASE_ADDRESS
1197 Base address where the generic TPM device is mapped
1198 to. Contemporary x86 systems usually map it at
1202 At the moment only the UHCI host controller is
1203 supported (PIP405, MIP405, MPC5200); define
1204 CONFIG_USB_UHCI to enable it.
1205 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1206 and define CONFIG_USB_STORAGE to enable the USB
1209 Supported are USB Keyboards and USB Floppy drives
1211 MPC5200 USB requires additional defines:
1213 for 528 MHz Clock: 0x0001bbbb
1217 for differential drivers: 0x00001000
1218 for single ended drivers: 0x00005000
1219 for differential drivers on PSC3: 0x00000100
1220 for single ended drivers on PSC3: 0x00004100
1221 CONFIG_SYS_USB_EVENT_POLL
1222 May be defined to allow interrupt polling
1223 instead of using asynchronous interrupts
1225 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1226 txfilltuning field in the EHCI controller on reset.
1229 Define the below if you wish to use the USB console.
1230 Once firmware is rebuilt from a serial console issue the
1231 command "setenv stdin usbtty; setenv stdout usbtty" and
1232 attach your USB cable. The Unix command "dmesg" should print
1233 it has found a new device. The environment variable usbtty
1234 can be set to gserial or cdc_acm to enable your device to
1235 appear to a USB host as a Linux gserial device or a
1236 Common Device Class Abstract Control Model serial device.
1237 If you select usbtty = gserial you should be able to enumerate
1239 # modprobe usbserial vendor=0xVendorID product=0xProductID
1240 else if using cdc_acm, simply setting the environment
1241 variable usbtty to be cdc_acm should suffice. The following
1242 might be defined in YourBoardName.h
1245 Define this to build a UDC device
1248 Define this to have a tty type of device available to
1249 talk to the UDC device
1252 Define this to enable the high speed support for usb
1253 device and usbtty. If this feature is enabled, a routine
1254 int is_usbd_high_speed(void)
1255 also needs to be defined by the driver to dynamically poll
1256 whether the enumeration has succeded at high speed or full
1259 CONFIG_SYS_CONSOLE_IS_IN_ENV
1260 Define this if you want stdin, stdout &/or stderr to
1264 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1265 Derive USB clock from external clock "blah"
1266 - CONFIG_SYS_USB_EXTC_CLK 0x02
1268 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1269 Derive USB clock from brgclk
1270 - CONFIG_SYS_USB_BRG_CLK 0x04
1272 If you have a USB-IF assigned VendorID then you may wish to
1273 define your own vendor specific values either in BoardName.h
1274 or directly in usbd_vendor_info.h. If you don't define
1275 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1276 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1277 should pretend to be a Linux device to it's target host.
1279 CONFIG_USBD_MANUFACTURER
1280 Define this string as the name of your company for
1281 - CONFIG_USBD_MANUFACTURER "my company"
1283 CONFIG_USBD_PRODUCT_NAME
1284 Define this string as the name of your product
1285 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1287 CONFIG_USBD_VENDORID
1288 Define this as your assigned Vendor ID from the USB
1289 Implementors Forum. This *must* be a genuine Vendor ID
1290 to avoid polluting the USB namespace.
1291 - CONFIG_USBD_VENDORID 0xFFFF
1293 CONFIG_USBD_PRODUCTID
1294 Define this as the unique Product ID
1296 - CONFIG_USBD_PRODUCTID 0xFFFF
1298 - ULPI Layer Support:
1299 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1300 the generic ULPI layer. The generic layer accesses the ULPI PHY
1301 via the platform viewport, so you need both the genric layer and
1302 the viewport enabled. Currently only Chipidea/ARC based
1303 viewport is supported.
1304 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1305 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1306 If your ULPI phy needs a different reference clock than the
1307 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1308 the appropriate value in Hz.
1311 The MMC controller on the Intel PXA is supported. To
1312 enable this define CONFIG_MMC. The MMC can be
1313 accessed from the boot prompt by mapping the device
1314 to physical memory similar to flash. Command line is
1315 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1316 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1319 Support for Renesas on-chip MMCIF controller
1321 CONFIG_SH_MMCIF_ADDR
1322 Define the base address of MMCIF registers
1325 Define the clock frequency for MMCIF
1327 - Journaling Flash filesystem support:
1328 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1329 CONFIG_JFFS2_NAND_DEV
1330 Define these for a default partition on a NAND device
1332 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1333 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1334 Define these for a default partition on a NOR device
1336 CONFIG_SYS_JFFS_CUSTOM_PART
1337 Define this to create an own partition. You have to provide a
1338 function struct part_info* jffs2_part_info(int part_num)
1340 If you define only one JFFS2 partition you may also want to
1341 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1342 to disable the command chpart. This is the default when you
1343 have not defined a custom partition
1345 - FAT(File Allocation Table) filesystem write function support:
1348 Define this to enable support for saving memory data as a
1349 file in FAT formatted partition.
1351 This will also enable the command "fatwrite" enabling the
1352 user to write files to FAT.
1354 CBFS (Coreboot Filesystem) support
1357 Define this to enable support for reading from a Coreboot
1358 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1364 Define this to enable standard (PC-Style) keyboard
1368 Standard PC keyboard driver with US (is default) and
1369 GERMAN key layout (switch via environment 'keymap=de') support.
1370 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1371 for cfb_console. Supports cursor blinking.
1376 Define this to enable video support (for output to
1379 CONFIG_VIDEO_CT69000
1381 Enable Chips & Technologies 69000 Video chip
1383 CONFIG_VIDEO_SMI_LYNXEM
1384 Enable Silicon Motion SMI 712/710/810 Video chip. The
1385 video output is selected via environment 'videoout'
1386 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1389 For the CT69000 and SMI_LYNXEM drivers, videomode is
1390 selected via environment 'videomode'. Two different ways
1392 - "videomode=num" 'num' is a standard LiLo mode numbers.
1393 Following standard modes are supported (* is default):
1395 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1396 -------------+---------------------------------------------
1397 8 bits | 0x301* 0x303 0x305 0x161 0x307
1398 15 bits | 0x310 0x313 0x316 0x162 0x319
1399 16 bits | 0x311 0x314 0x317 0x163 0x31A
1400 24 bits | 0x312 0x315 0x318 ? 0x31B
1401 -------------+---------------------------------------------
1402 (i.e. setenv videomode 317; saveenv; reset;)
1404 - "videomode=bootargs" all the video parameters are parsed
1405 from the bootargs. (See drivers/video/videomodes.c)
1408 CONFIG_VIDEO_SED13806
1409 Enable Epson SED13806 driver. This driver supports 8bpp
1410 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1411 or CONFIG_VIDEO_SED13806_16BPP
1414 Enable the Freescale DIU video driver. Reference boards for
1415 SOCs that have a DIU should define this macro to enable DIU
1416 support, and should also define these other macros:
1422 CONFIG_VIDEO_SW_CURSOR
1423 CONFIG_VGA_AS_SINGLE_DEVICE
1425 CONFIG_VIDEO_BMP_LOGO
1427 The DIU driver will look for the 'video-mode' environment
1428 variable, and if defined, enable the DIU as a console during
1429 boot. See the documentation file README.video for a
1430 description of this variable.
1434 Enable the VGA video / BIOS for x86. The alternative if you
1435 are using coreboot is to use the coreboot frame buffer
1442 Define this to enable a custom keyboard support.
1443 This simply calls drv_keyboard_init() which must be
1444 defined in your board-specific files.
1445 The only board using this so far is RBC823.
1447 - LCD Support: CONFIG_LCD
1449 Define this to enable LCD support (for output to LCD
1450 display); also select one of the supported displays
1451 by defining one of these:
1455 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1457 CONFIG_NEC_NL6448AC33:
1459 NEC NL6448AC33-18. Active, color, single scan.
1461 CONFIG_NEC_NL6448BC20
1463 NEC NL6448BC20-08. 6.5", 640x480.
1464 Active, color, single scan.
1466 CONFIG_NEC_NL6448BC33_54
1468 NEC NL6448BC33-54. 10.4", 640x480.
1469 Active, color, single scan.
1473 Sharp 320x240. Active, color, single scan.
1474 It isn't 16x9, and I am not sure what it is.
1476 CONFIG_SHARP_LQ64D341
1478 Sharp LQ64D341 display, 640x480.
1479 Active, color, single scan.
1483 HLD1045 display, 640x480.
1484 Active, color, single scan.
1488 Optrex CBL50840-2 NF-FW 99 22 M5
1490 Hitachi LMG6912RPFC-00T
1494 320x240. Black & white.
1496 Normally display is black on white background; define
1497 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1499 CONFIG_LCD_ALIGNMENT
1501 Normally the LCD is page-aligned (tyically 4KB). If this is
1502 defined then the LCD will be aligned to this value instead.
1503 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1504 here, since it is cheaper to change data cache settings on
1505 a per-section basis.
1507 CONFIG_CONSOLE_SCROLL_LINES
1509 When the console need to be scrolled, this is the number of
1510 lines to scroll by. It defaults to 1. Increasing this makes
1511 the console jump but can help speed up operation when scrolling
1516 Support drawing of RLE8-compressed bitmaps on the LCD.
1520 Enables an 'i2c edid' command which can read EDID
1521 information over I2C from an attached LCD display.
1523 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1525 If this option is set, the environment is checked for
1526 a variable "splashimage". If found, the usual display
1527 of logo, copyright and system information on the LCD
1528 is suppressed and the BMP image at the address
1529 specified in "splashimage" is loaded instead. The
1530 console is redirected to the "nulldev", too. This
1531 allows for a "silent" boot where a splash screen is
1532 loaded very quickly after power-on.
1534 CONFIG_SPLASH_SCREEN_ALIGN
1536 If this option is set the splash image can be freely positioned
1537 on the screen. Environment variable "splashpos" specifies the
1538 position as "x,y". If a positive number is given it is used as
1539 number of pixel from left/top. If a negative number is given it
1540 is used as number of pixel from right/bottom. You can also
1541 specify 'm' for centering the image.
1544 setenv splashpos m,m
1545 => image at center of screen
1547 setenv splashpos 30,20
1548 => image at x = 30 and y = 20
1550 setenv splashpos -10,m
1551 => vertically centered image
1552 at x = dspWidth - bmpWidth - 9
1554 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1556 If this option is set, additionally to standard BMP
1557 images, gzipped BMP images can be displayed via the
1558 splashscreen support or the bmp command.
1560 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1562 If this option is set, 8-bit RLE compressed BMP images
1563 can be displayed via the splashscreen support or the
1566 - Do compresssing for memory range:
1569 If this option is set, it would use zlib deflate method
1570 to compress the specified memory at its best effort.
1572 - Compression support:
1575 If this option is set, support for bzip2 compressed
1576 images is included. If not, only uncompressed and gzip
1577 compressed images are supported.
1579 NOTE: the bzip2 algorithm requires a lot of RAM, so
1580 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1585 If this option is set, support for lzma compressed
1588 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1589 requires an amount of dynamic memory that is given by the
1592 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1594 Where lc and lp stand for, respectively, Literal context bits
1595 and Literal pos bits.
1597 This value is upper-bounded by 14MB in the worst case. Anyway,
1598 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1599 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1600 a very small buffer.
1602 Use the lzmainfo tool to determinate the lc and lp values and
1603 then calculate the amount of needed dynamic memory (ensuring
1604 the appropriate CONFIG_SYS_MALLOC_LEN value).
1609 The address of PHY on MII bus.
1611 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1613 The clock frequency of the MII bus
1617 If this option is set, support for speed/duplex
1618 detection of gigabit PHY is included.
1620 CONFIG_PHY_RESET_DELAY
1622 Some PHY like Intel LXT971A need extra delay after
1623 reset before any MII register access is possible.
1624 For such PHY, set this option to the usec delay
1625 required. (minimum 300usec for LXT971A)
1627 CONFIG_PHY_CMD_DELAY (ppc4xx)
1629 Some PHY like Intel LXT971A need extra delay after
1630 command issued before MII status register can be read
1640 Define a default value for Ethernet address to use
1641 for the respective Ethernet interface, in case this
1642 is not determined automatically.
1647 Define a default value for the IP address to use for
1648 the default Ethernet interface, in case this is not
1649 determined through e.g. bootp.
1650 (Environment variable "ipaddr")
1652 - Server IP address:
1655 Defines a default value for the IP address of a TFTP
1656 server to contact when using the "tftboot" command.
1657 (Environment variable "serverip")
1659 CONFIG_KEEP_SERVERADDR
1661 Keeps the server's MAC address, in the env 'serveraddr'
1662 for passing to bootargs (like Linux's netconsole option)
1664 - Gateway IP address:
1667 Defines a default value for the IP address of the
1668 default router where packets to other networks are
1670 (Environment variable "gatewayip")
1675 Defines a default value for the subnet mask (or
1676 routing prefix) which is used to determine if an IP
1677 address belongs to the local subnet or needs to be
1678 forwarded through a router.
1679 (Environment variable "netmask")
1681 - Multicast TFTP Mode:
1684 Defines whether you want to support multicast TFTP as per
1685 rfc-2090; for example to work with atftp. Lets lots of targets
1686 tftp down the same boot image concurrently. Note: the Ethernet
1687 driver in use must provide a function: mcast() to join/leave a
1690 - BOOTP Recovery Mode:
1691 CONFIG_BOOTP_RANDOM_DELAY
1693 If you have many targets in a network that try to
1694 boot using BOOTP, you may want to avoid that all
1695 systems send out BOOTP requests at precisely the same
1696 moment (which would happen for instance at recovery
1697 from a power failure, when all systems will try to
1698 boot, thus flooding the BOOTP server. Defining
1699 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1700 inserted before sending out BOOTP requests. The
1701 following delays are inserted then:
1703 1st BOOTP request: delay 0 ... 1 sec
1704 2nd BOOTP request: delay 0 ... 2 sec
1705 3rd BOOTP request: delay 0 ... 4 sec
1707 BOOTP requests: delay 0 ... 8 sec
1709 - DHCP Advanced Options:
1710 You can fine tune the DHCP functionality by defining
1711 CONFIG_BOOTP_* symbols:
1713 CONFIG_BOOTP_SUBNETMASK
1714 CONFIG_BOOTP_GATEWAY
1715 CONFIG_BOOTP_HOSTNAME
1716 CONFIG_BOOTP_NISDOMAIN
1717 CONFIG_BOOTP_BOOTPATH
1718 CONFIG_BOOTP_BOOTFILESIZE
1721 CONFIG_BOOTP_SEND_HOSTNAME
1722 CONFIG_BOOTP_NTPSERVER
1723 CONFIG_BOOTP_TIMEOFFSET
1724 CONFIG_BOOTP_VENDOREX
1725 CONFIG_BOOTP_MAY_FAIL
1727 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1728 environment variable, not the BOOTP server.
1730 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1731 after the configured retry count, the call will fail
1732 instead of starting over. This can be used to fail over
1733 to Link-local IP address configuration if the DHCP server
1736 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1737 serverip from a DHCP server, it is possible that more
1738 than one DNS serverip is offered to the client.
1739 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1740 serverip will be stored in the additional environment
1741 variable "dnsip2". The first DNS serverip is always
1742 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1745 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1746 to do a dynamic update of a DNS server. To do this, they
1747 need the hostname of the DHCP requester.
1748 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1749 of the "hostname" environment variable is passed as
1750 option 12 to the DHCP server.
1752 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1754 A 32bit value in microseconds for a delay between
1755 receiving a "DHCP Offer" and sending the "DHCP Request".
1756 This fixes a problem with certain DHCP servers that don't
1757 respond 100% of the time to a "DHCP request". E.g. On an
1758 AT91RM9200 processor running at 180MHz, this delay needed
1759 to be *at least* 15,000 usec before a Windows Server 2003
1760 DHCP server would reply 100% of the time. I recommend at
1761 least 50,000 usec to be safe. The alternative is to hope
1762 that one of the retries will be successful but note that
1763 the DHCP timeout and retry process takes a longer than
1766 - Link-local IP address negotiation:
1767 Negotiate with other link-local clients on the local network
1768 for an address that doesn't require explicit configuration.
1769 This is especially useful if a DHCP server cannot be guaranteed
1770 to exist in all environments that the device must operate.
1772 See doc/README.link-local for more information.
1775 CONFIG_CDP_DEVICE_ID
1777 The device id used in CDP trigger frames.
1779 CONFIG_CDP_DEVICE_ID_PREFIX
1781 A two character string which is prefixed to the MAC address
1786 A printf format string which contains the ascii name of
1787 the port. Normally is set to "eth%d" which sets
1788 eth0 for the first Ethernet, eth1 for the second etc.
1790 CONFIG_CDP_CAPABILITIES
1792 A 32bit integer which indicates the device capabilities;
1793 0x00000010 for a normal host which does not forwards.
1797 An ascii string containing the version of the software.
1801 An ascii string containing the name of the platform.
1805 A 32bit integer sent on the trigger.
1807 CONFIG_CDP_POWER_CONSUMPTION
1809 A 16bit integer containing the power consumption of the
1810 device in .1 of milliwatts.
1812 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1814 A byte containing the id of the VLAN.
1816 - Status LED: CONFIG_STATUS_LED
1818 Several configurations allow to display the current
1819 status using a LED. For instance, the LED will blink
1820 fast while running U-Boot code, stop blinking as
1821 soon as a reply to a BOOTP request was received, and
1822 start blinking slow once the Linux kernel is running
1823 (supported by a status LED driver in the Linux
1824 kernel). Defining CONFIG_STATUS_LED enables this
1827 - CAN Support: CONFIG_CAN_DRIVER
1829 Defining CONFIG_CAN_DRIVER enables CAN driver support
1830 on those systems that support this (optional)
1831 feature, like the TQM8xxL modules.
1833 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1835 These enable I2C serial bus commands. Defining either of
1836 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1837 include the appropriate I2C driver for the selected CPU.
1839 This will allow you to use i2c commands at the u-boot
1840 command line (as long as you set CONFIG_CMD_I2C in
1841 CONFIG_COMMANDS) and communicate with i2c based realtime
1842 clock chips. See common/cmd_i2c.c for a description of the
1843 command line interface.
1845 CONFIG_HARD_I2C selects a hardware I2C controller.
1847 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1848 bit-banging) driver instead of CPM or similar hardware
1851 There are several other quantities that must also be
1852 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1854 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1855 to be the frequency (in Hz) at which you wish your i2c bus
1856 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1857 the CPU's i2c node address).
1859 Now, the u-boot i2c code for the mpc8xx
1860 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1861 and so its address should therefore be cleared to 0 (See,
1862 eg, MPC823e User's Manual p.16-473). So, set
1863 CONFIG_SYS_I2C_SLAVE to 0.
1865 CONFIG_SYS_I2C_INIT_MPC5XXX
1867 When a board is reset during an i2c bus transfer
1868 chips might think that the current transfer is still
1869 in progress. Reset the slave devices by sending start
1870 commands until the slave device responds.
1872 That's all that's required for CONFIG_HARD_I2C.
1874 If you use the software i2c interface (CONFIG_SOFT_I2C)
1875 then the following macros need to be defined (examples are
1876 from include/configs/lwmon.h):
1880 (Optional). Any commands necessary to enable the I2C
1881 controller or configure ports.
1883 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1887 (Only for MPC8260 CPU). The I/O port to use (the code
1888 assumes both bits are on the same port). Valid values
1889 are 0..3 for ports A..D.
1893 The code necessary to make the I2C data line active
1894 (driven). If the data line is open collector, this
1897 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1901 The code necessary to make the I2C data line tri-stated
1902 (inactive). If the data line is open collector, this
1905 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1909 Code that returns TRUE if the I2C data line is high,
1912 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1916 If <bit> is TRUE, sets the I2C data line high. If it
1917 is FALSE, it clears it (low).
1919 eg: #define I2C_SDA(bit) \
1920 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1921 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1925 If <bit> is TRUE, sets the I2C clock line high. If it
1926 is FALSE, it clears it (low).
1928 eg: #define I2C_SCL(bit) \
1929 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1930 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1934 This delay is invoked four times per clock cycle so this
1935 controls the rate of data transfer. The data rate thus
1936 is 1 / (I2C_DELAY * 4). Often defined to be something
1939 #define I2C_DELAY udelay(2)
1941 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1943 If your arch supports the generic GPIO framework (asm/gpio.h),
1944 then you may alternatively define the two GPIOs that are to be
1945 used as SCL / SDA. Any of the previous I2C_xxx macros will
1946 have GPIO-based defaults assigned to them as appropriate.
1948 You should define these to the GPIO value as given directly to
1949 the generic GPIO functions.
1951 CONFIG_SYS_I2C_INIT_BOARD
1953 When a board is reset during an i2c bus transfer
1954 chips might think that the current transfer is still
1955 in progress. On some boards it is possible to access
1956 the i2c SCLK line directly, either by using the
1957 processor pin as a GPIO or by having a second pin
1958 connected to the bus. If this option is defined a
1959 custom i2c_init_board() routine in boards/xxx/board.c
1960 is run early in the boot sequence.
1962 CONFIG_SYS_I2C_BOARD_LATE_INIT
1964 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1965 defined a custom i2c_board_late_init() routine in
1966 boards/xxx/board.c is run AFTER the operations in i2c_init()
1967 is completed. This callpoint can be used to unreset i2c bus
1968 using CPU i2c controller register accesses for CPUs whose i2c
1969 controller provide such a method. It is called at the end of
1970 i2c_init() to allow i2c_init operations to setup the i2c bus
1971 controller on the CPU (e.g. setting bus speed & slave address).
1973 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1975 This option enables configuration of bi_iic_fast[] flags
1976 in u-boot bd_info structure based on u-boot environment
1977 variable "i2cfast". (see also i2cfast)
1979 CONFIG_I2C_MULTI_BUS
1981 This option allows the use of multiple I2C buses, each of which
1982 must have a controller. At any point in time, only one bus is
1983 active. To switch to a different bus, use the 'i2c dev' command.
1984 Note that bus numbering is zero-based.
1986 CONFIG_SYS_I2C_NOPROBES
1988 This option specifies a list of I2C devices that will be skipped
1989 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1990 is set, specify a list of bus-device pairs. Otherwise, specify
1991 a 1D array of device addresses
1994 #undef CONFIG_I2C_MULTI_BUS
1995 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1997 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1999 #define CONFIG_I2C_MULTI_BUS
2000 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2002 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2004 CONFIG_SYS_SPD_BUS_NUM
2006 If defined, then this indicates the I2C bus number for DDR SPD.
2007 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2009 CONFIG_SYS_RTC_BUS_NUM
2011 If defined, then this indicates the I2C bus number for the RTC.
2012 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2014 CONFIG_SYS_DTT_BUS_NUM
2016 If defined, then this indicates the I2C bus number for the DTT.
2017 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2019 CONFIG_SYS_I2C_DTT_ADDR:
2021 If defined, specifies the I2C address of the DTT device.
2022 If not defined, then U-Boot uses predefined value for
2023 specified DTT device.
2027 Define this option if you want to use Freescale's I2C driver in
2028 drivers/i2c/fsl_i2c.c.
2032 Define this option if you have I2C devices reached over 1 .. n
2033 I2C Muxes like the pca9544a. This option addes a new I2C
2034 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2035 new I2C Bus to the existing I2C Busses. If you select the
2036 new Bus with "i2c dev", u-bbot sends first the commandos for
2037 the muxes to activate this new "bus".
2039 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2043 Adding a new I2C Bus reached over 2 pca9544a muxes
2044 The First mux with address 70 and channel 6
2045 The Second mux with address 71 and channel 4
2047 => i2c bus pca9544a:70:6:pca9544a:71:4
2049 Use the "i2c bus" command without parameter, to get a list
2050 of I2C Busses with muxes:
2053 Busses reached over muxes:
2055 reached over Mux(es):
2058 reached over Mux(es):
2063 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2064 u-boot first sends the command to the mux@70 to enable
2065 channel 6, and then the command to the mux@71 to enable
2068 After that, you can use the "normal" i2c commands as
2069 usual to communicate with your I2C devices behind
2072 This option is actually implemented for the bitbanging
2073 algorithm in common/soft_i2c.c and for the Hardware I2C
2074 Bus on the MPC8260. But it should be not so difficult
2075 to add this option to other architectures.
2077 CONFIG_SOFT_I2C_READ_REPEATED_START
2079 defining this will force the i2c_read() function in
2080 the soft_i2c driver to perform an I2C repeated start
2081 between writing the address pointer and reading the
2082 data. If this define is omitted the default behaviour
2083 of doing a stop-start sequence will be used. Most I2C
2084 devices can use either method, but some require one or
2087 - SPI Support: CONFIG_SPI
2089 Enables SPI driver (so far only tested with
2090 SPI EEPROM, also an instance works with Crystal A/D and
2091 D/As on the SACSng board)
2095 Enables the driver for SPI controller on SuperH. Currently
2096 only SH7757 is supported.
2100 Enables extended (16-bit) SPI EEPROM addressing.
2101 (symmetrical to CONFIG_I2C_X)
2105 Enables a software (bit-bang) SPI driver rather than
2106 using hardware support. This is a general purpose
2107 driver that only requires three general I/O port pins
2108 (two outputs, one input) to function. If this is
2109 defined, the board configuration must define several
2110 SPI configuration items (port pins to use, etc). For
2111 an example, see include/configs/sacsng.h.
2115 Enables a hardware SPI driver for general-purpose reads
2116 and writes. As with CONFIG_SOFT_SPI, the board configuration
2117 must define a list of chip-select function pointers.
2118 Currently supported on some MPC8xxx processors. For an
2119 example, see include/configs/mpc8349emds.h.
2123 Enables the driver for the SPI controllers on i.MX and MXC
2124 SoCs. Currently i.MX31/35/51 are supported.
2126 - FPGA Support: CONFIG_FPGA
2128 Enables FPGA subsystem.
2130 CONFIG_FPGA_<vendor>
2132 Enables support for specific chip vendors.
2135 CONFIG_FPGA_<family>
2137 Enables support for FPGA family.
2138 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2142 Specify the number of FPGA devices to support.
2144 CONFIG_SYS_FPGA_PROG_FEEDBACK
2146 Enable printing of hash marks during FPGA configuration.
2148 CONFIG_SYS_FPGA_CHECK_BUSY
2150 Enable checks on FPGA configuration interface busy
2151 status by the configuration function. This option
2152 will require a board or device specific function to
2157 If defined, a function that provides delays in the FPGA
2158 configuration driver.
2160 CONFIG_SYS_FPGA_CHECK_CTRLC
2161 Allow Control-C to interrupt FPGA configuration
2163 CONFIG_SYS_FPGA_CHECK_ERROR
2165 Check for configuration errors during FPGA bitfile
2166 loading. For example, abort during Virtex II
2167 configuration if the INIT_B line goes low (which
2168 indicated a CRC error).
2170 CONFIG_SYS_FPGA_WAIT_INIT
2172 Maximum time to wait for the INIT_B line to deassert
2173 after PROB_B has been deasserted during a Virtex II
2174 FPGA configuration sequence. The default time is 500
2177 CONFIG_SYS_FPGA_WAIT_BUSY
2179 Maximum time to wait for BUSY to deassert during
2180 Virtex II FPGA configuration. The default is 5 ms.
2182 CONFIG_SYS_FPGA_WAIT_CONFIG
2184 Time to wait after FPGA configuration. The default is
2187 - Configuration Management:
2190 If defined, this string will be added to the U-Boot
2191 version information (U_BOOT_VERSION)
2193 - Vendor Parameter Protection:
2195 U-Boot considers the values of the environment
2196 variables "serial#" (Board Serial Number) and
2197 "ethaddr" (Ethernet Address) to be parameters that
2198 are set once by the board vendor / manufacturer, and
2199 protects these variables from casual modification by
2200 the user. Once set, these variables are read-only,
2201 and write or delete attempts are rejected. You can
2202 change this behaviour:
2204 If CONFIG_ENV_OVERWRITE is #defined in your config
2205 file, the write protection for vendor parameters is
2206 completely disabled. Anybody can change or delete
2209 Alternatively, if you #define _both_ CONFIG_ETHADDR
2210 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2211 Ethernet address is installed in the environment,
2212 which can be changed exactly ONCE by the user. [The
2213 serial# is unaffected by this, i. e. it remains
2216 The same can be accomplished in a more flexible way
2217 for any variable by configuring the type of access
2218 to allow for those variables in the ".flags" variable
2219 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2224 Define this variable to enable the reservation of
2225 "protected RAM", i. e. RAM which is not overwritten
2226 by U-Boot. Define CONFIG_PRAM to hold the number of
2227 kB you want to reserve for pRAM. You can overwrite
2228 this default value by defining an environment
2229 variable "pram" to the number of kB you want to
2230 reserve. Note that the board info structure will
2231 still show the full amount of RAM. If pRAM is
2232 reserved, a new environment variable "mem" will
2233 automatically be defined to hold the amount of
2234 remaining RAM in a form that can be passed as boot
2235 argument to Linux, for instance like that:
2237 setenv bootargs ... mem=\${mem}
2240 This way you can tell Linux not to use this memory,
2241 either, which results in a memory region that will
2242 not be affected by reboots.
2244 *WARNING* If your board configuration uses automatic
2245 detection of the RAM size, you must make sure that
2246 this memory test is non-destructive. So far, the
2247 following board configurations are known to be
2250 IVMS8, IVML24, SPD8xx, TQM8xxL,
2251 HERMES, IP860, RPXlite, LWMON,
2254 - Access to physical memory region (> 4GB)
2255 Some basic support is provided for operations on memory not
2256 normally accessible to U-Boot - e.g. some architectures
2257 support access to more than 4GB of memory on 32-bit
2258 machines using physical address extension or similar.
2259 Define CONFIG_PHYSMEM to access this basic support, which
2260 currently only supports clearing the memory.
2265 Define this variable to stop the system in case of a
2266 fatal error, so that you have to reset it manually.
2267 This is probably NOT a good idea for an embedded
2268 system where you want the system to reboot
2269 automatically as fast as possible, but it may be
2270 useful during development since you can try to debug
2271 the conditions that lead to the situation.
2273 CONFIG_NET_RETRY_COUNT
2275 This variable defines the number of retries for
2276 network operations like ARP, RARP, TFTP, or BOOTP
2277 before giving up the operation. If not defined, a
2278 default value of 5 is used.
2282 Timeout waiting for an ARP reply in milliseconds.
2286 Timeout in milliseconds used in NFS protocol.
2287 If you encounter "ERROR: Cannot umount" in nfs command,
2288 try longer timeout such as
2289 #define CONFIG_NFS_TIMEOUT 10000UL
2291 - Command Interpreter:
2292 CONFIG_AUTO_COMPLETE
2294 Enable auto completion of commands using TAB.
2296 Note that this feature has NOT been implemented yet
2297 for the "hush" shell.
2300 CONFIG_SYS_HUSH_PARSER
2302 Define this variable to enable the "hush" shell (from
2303 Busybox) as command line interpreter, thus enabling
2304 powerful command line syntax like
2305 if...then...else...fi conditionals or `&&' and '||'
2306 constructs ("shell scripts").
2308 If undefined, you get the old, much simpler behaviour
2309 with a somewhat smaller memory footprint.
2312 CONFIG_SYS_PROMPT_HUSH_PS2
2314 This defines the secondary prompt string, which is
2315 printed when the command interpreter needs more input
2316 to complete a command. Usually "> ".
2320 In the current implementation, the local variables
2321 space and global environment variables space are
2322 separated. Local variables are those you define by
2323 simply typing `name=value'. To access a local
2324 variable later on, you have write `$name' or
2325 `${name}'; to execute the contents of a variable
2326 directly type `$name' at the command prompt.
2328 Global environment variables are those you use
2329 setenv/printenv to work with. To run a command stored
2330 in such a variable, you need to use the run command,
2331 and you must not use the '$' sign to access them.
2333 To store commands and special characters in a
2334 variable, please use double quotation marks
2335 surrounding the whole text of the variable, instead
2336 of the backslashes before semicolons and special
2339 - Commandline Editing and History:
2340 CONFIG_CMDLINE_EDITING
2342 Enable editing and History functions for interactive
2343 commandline input operations
2345 - Default Environment:
2346 CONFIG_EXTRA_ENV_SETTINGS
2348 Define this to contain any number of null terminated
2349 strings (variable = value pairs) that will be part of
2350 the default environment compiled into the boot image.
2352 For example, place something like this in your
2353 board's config file:
2355 #define CONFIG_EXTRA_ENV_SETTINGS \
2359 Warning: This method is based on knowledge about the
2360 internal format how the environment is stored by the
2361 U-Boot code. This is NOT an official, exported
2362 interface! Although it is unlikely that this format
2363 will change soon, there is no guarantee either.
2364 You better know what you are doing here.
2366 Note: overly (ab)use of the default environment is
2367 discouraged. Make sure to check other ways to preset
2368 the environment like the "source" command or the
2371 CONFIG_ENV_VARS_UBOOT_CONFIG
2373 Define this in order to add variables describing the
2374 U-Boot build configuration to the default environment.
2375 These will be named arch, cpu, board, vendor, and soc.
2377 Enabling this option will cause the following to be defined:
2385 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2387 Define this in order to add variables describing certain
2388 run-time determined information about the hardware to the
2389 environment. These will be named board_name, board_rev.
2391 CONFIG_DELAY_ENVIRONMENT
2393 Normally the environment is loaded when the board is
2394 intialised so that it is available to U-Boot. This inhibits
2395 that so that the environment is not available until
2396 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2397 this is instead controlled by the value of
2398 /config/load-environment.
2400 - DataFlash Support:
2401 CONFIG_HAS_DATAFLASH
2403 Defining this option enables DataFlash features and
2404 allows to read/write in Dataflash via the standard
2407 - Serial Flash support
2410 Defining this option enables SPI flash commands
2411 'sf probe/read/write/erase/update'.
2413 Usage requires an initial 'probe' to define the serial
2414 flash parameters, followed by read/write/erase/update
2417 The following defaults may be provided by the platform
2418 to handle the common case when only a single serial
2419 flash is present on the system.
2421 CONFIG_SF_DEFAULT_BUS Bus identifier
2422 CONFIG_SF_DEFAULT_CS Chip-select
2423 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2424 CONFIG_SF_DEFAULT_SPEED in Hz
2428 Define this option to include a destructive SPI flash
2431 - SystemACE Support:
2434 Adding this option adds support for Xilinx SystemACE
2435 chips attached via some sort of local bus. The address
2436 of the chip must also be defined in the
2437 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2439 #define CONFIG_SYSTEMACE
2440 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2442 When SystemACE support is added, the "ace" device type
2443 becomes available to the fat commands, i.e. fatls.
2445 - TFTP Fixed UDP Port:
2448 If this is defined, the environment variable tftpsrcp
2449 is used to supply the TFTP UDP source port value.
2450 If tftpsrcp isn't defined, the normal pseudo-random port
2451 number generator is used.
2453 Also, the environment variable tftpdstp is used to supply
2454 the TFTP UDP destination port value. If tftpdstp isn't
2455 defined, the normal port 69 is used.
2457 The purpose for tftpsrcp is to allow a TFTP server to
2458 blindly start the TFTP transfer using the pre-configured
2459 target IP address and UDP port. This has the effect of
2460 "punching through" the (Windows XP) firewall, allowing
2461 the remainder of the TFTP transfer to proceed normally.
2462 A better solution is to properly configure the firewall,
2463 but sometimes that is not allowed.
2468 This enables a generic 'hash' command which can produce
2469 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2473 Enable the hash verify command (hash -v). This adds to code
2476 CONFIG_SHA1 - support SHA1 hashing
2477 CONFIG_SHA256 - support SHA256 hashing
2479 Note: There is also a sha1sum command, which should perhaps
2480 be deprecated in favour of 'hash sha1'.
2482 - Show boot progress:
2483 CONFIG_SHOW_BOOT_PROGRESS
2485 Defining this option allows to add some board-
2486 specific code (calling a user-provided function
2487 "show_boot_progress(int)") that enables you to show
2488 the system's boot progress on some display (for
2489 example, some LED's) on your board. At the moment,
2490 the following checkpoints are implemented:
2492 - Detailed boot stage timing
2494 Define this option to get detailed timing of each stage
2495 of the boot process.
2497 CONFIG_BOOTSTAGE_USER_COUNT
2498 This is the number of available user bootstage records.
2499 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2500 a new ID will be allocated from this stash. If you exceed
2501 the limit, recording will stop.
2503 CONFIG_BOOTSTAGE_REPORT
2504 Define this to print a report before boot, similar to this:
2506 Timer summary in microseconds:
2509 3,575,678 3,575,678 board_init_f start
2510 3,575,695 17 arch_cpu_init A9
2511 3,575,777 82 arch_cpu_init done
2512 3,659,598 83,821 board_init_r start
2513 3,910,375 250,777 main_loop
2514 29,916,167 26,005,792 bootm_start
2515 30,361,327 445,160 start_kernel
2517 CONFIG_CMD_BOOTSTAGE
2518 Add a 'bootstage' command which supports printing a report
2519 and un/stashing of bootstage data.
2521 CONFIG_BOOTSTAGE_FDT
2522 Stash the bootstage information in the FDT. A root 'bootstage'
2523 node is created with each bootstage id as a child. Each child
2524 has a 'name' property and either 'mark' containing the
2525 mark time in microsecond, or 'accum' containing the
2526 accumulated time for that bootstage id in microseconds.
2531 name = "board_init_f";
2540 Code in the Linux kernel can find this in /proc/devicetree.
2542 Legacy uImage format:
2545 1 common/cmd_bootm.c before attempting to boot an image
2546 -1 common/cmd_bootm.c Image header has bad magic number
2547 2 common/cmd_bootm.c Image header has correct magic number
2548 -2 common/cmd_bootm.c Image header has bad checksum
2549 3 common/cmd_bootm.c Image header has correct checksum
2550 -3 common/cmd_bootm.c Image data has bad checksum
2551 4 common/cmd_bootm.c Image data has correct checksum
2552 -4 common/cmd_bootm.c Image is for unsupported architecture
2553 5 common/cmd_bootm.c Architecture check OK
2554 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2555 6 common/cmd_bootm.c Image Type check OK
2556 -6 common/cmd_bootm.c gunzip uncompression error
2557 -7 common/cmd_bootm.c Unimplemented compression type
2558 7 common/cmd_bootm.c Uncompression OK
2559 8 common/cmd_bootm.c No uncompress/copy overwrite error
2560 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2562 9 common/image.c Start initial ramdisk verification
2563 -10 common/image.c Ramdisk header has bad magic number
2564 -11 common/image.c Ramdisk header has bad checksum
2565 10 common/image.c Ramdisk header is OK
2566 -12 common/image.c Ramdisk data has bad checksum
2567 11 common/image.c Ramdisk data has correct checksum
2568 12 common/image.c Ramdisk verification complete, start loading
2569 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2570 13 common/image.c Start multifile image verification
2571 14 common/image.c No initial ramdisk, no multifile, continue.
2573 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2575 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2576 -31 post/post.c POST test failed, detected by post_output_backlog()
2577 -32 post/post.c POST test failed, detected by post_run_single()
2579 34 common/cmd_doc.c before loading a Image from a DOC device
2580 -35 common/cmd_doc.c Bad usage of "doc" command
2581 35 common/cmd_doc.c correct usage of "doc" command
2582 -36 common/cmd_doc.c No boot device
2583 36 common/cmd_doc.c correct boot device
2584 -37 common/cmd_doc.c Unknown Chip ID on boot device
2585 37 common/cmd_doc.c correct chip ID found, device available
2586 -38 common/cmd_doc.c Read Error on boot device
2587 38 common/cmd_doc.c reading Image header from DOC device OK
2588 -39 common/cmd_doc.c Image header has bad magic number
2589 39 common/cmd_doc.c Image header has correct magic number
2590 -40 common/cmd_doc.c Error reading Image from DOC device
2591 40 common/cmd_doc.c Image header has correct magic number
2592 41 common/cmd_ide.c before loading a Image from a IDE device
2593 -42 common/cmd_ide.c Bad usage of "ide" command
2594 42 common/cmd_ide.c correct usage of "ide" command
2595 -43 common/cmd_ide.c No boot device
2596 43 common/cmd_ide.c boot device found
2597 -44 common/cmd_ide.c Device not available
2598 44 common/cmd_ide.c Device available
2599 -45 common/cmd_ide.c wrong partition selected
2600 45 common/cmd_ide.c partition selected
2601 -46 common/cmd_ide.c Unknown partition table
2602 46 common/cmd_ide.c valid partition table found
2603 -47 common/cmd_ide.c Invalid partition type
2604 47 common/cmd_ide.c correct partition type
2605 -48 common/cmd_ide.c Error reading Image Header on boot device
2606 48 common/cmd_ide.c reading Image Header from IDE device OK
2607 -49 common/cmd_ide.c Image header has bad magic number
2608 49 common/cmd_ide.c Image header has correct magic number
2609 -50 common/cmd_ide.c Image header has bad checksum
2610 50 common/cmd_ide.c Image header has correct checksum
2611 -51 common/cmd_ide.c Error reading Image from IDE device
2612 51 common/cmd_ide.c reading Image from IDE device OK
2613 52 common/cmd_nand.c before loading a Image from a NAND device
2614 -53 common/cmd_nand.c Bad usage of "nand" command
2615 53 common/cmd_nand.c correct usage of "nand" command
2616 -54 common/cmd_nand.c No boot device
2617 54 common/cmd_nand.c boot device found
2618 -55 common/cmd_nand.c Unknown Chip ID on boot device
2619 55 common/cmd_nand.c correct chip ID found, device available
2620 -56 common/cmd_nand.c Error reading Image Header on boot device
2621 56 common/cmd_nand.c reading Image Header from NAND device OK
2622 -57 common/cmd_nand.c Image header has bad magic number
2623 57 common/cmd_nand.c Image header has correct magic number
2624 -58 common/cmd_nand.c Error reading Image from NAND device
2625 58 common/cmd_nand.c reading Image from NAND device OK
2627 -60 common/env_common.c Environment has a bad CRC, using default
2629 64 net/eth.c starting with Ethernet configuration.
2630 -64 net/eth.c no Ethernet found.
2631 65 net/eth.c Ethernet found.
2633 -80 common/cmd_net.c usage wrong
2634 80 common/cmd_net.c before calling NetLoop()
2635 -81 common/cmd_net.c some error in NetLoop() occurred
2636 81 common/cmd_net.c NetLoop() back without error
2637 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2638 82 common/cmd_net.c trying automatic boot
2639 83 common/cmd_net.c running "source" command
2640 -83 common/cmd_net.c some error in automatic boot or "source" command
2641 84 common/cmd_net.c end without errors
2646 100 common/cmd_bootm.c Kernel FIT Image has correct format
2647 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2648 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2649 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2650 102 common/cmd_bootm.c Kernel unit name specified
2651 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2652 103 common/cmd_bootm.c Found configuration node
2653 104 common/cmd_bootm.c Got kernel subimage node offset
2654 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2655 105 common/cmd_bootm.c Kernel subimage hash verification OK
2656 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2657 106 common/cmd_bootm.c Architecture check OK
2658 -106 common/cmd_bootm.c Kernel subimage has wrong type
2659 107 common/cmd_bootm.c Kernel subimage type OK
2660 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2661 108 common/cmd_bootm.c Got kernel subimage data/size
2662 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2663 -109 common/cmd_bootm.c Can't get kernel subimage type
2664 -110 common/cmd_bootm.c Can't get kernel subimage comp
2665 -111 common/cmd_bootm.c Can't get kernel subimage os
2666 -112 common/cmd_bootm.c Can't get kernel subimage load address
2667 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2669 120 common/image.c Start initial ramdisk verification
2670 -120 common/image.c Ramdisk FIT image has incorrect format
2671 121 common/image.c Ramdisk FIT image has correct format
2672 122 common/image.c No ramdisk subimage unit name, using configuration
2673 -122 common/image.c Can't get configuration for ramdisk subimage
2674 123 common/image.c Ramdisk unit name specified
2675 -124 common/image.c Can't get ramdisk subimage node offset
2676 125 common/image.c Got ramdisk subimage node offset
2677 -125 common/image.c Ramdisk subimage hash verification failed
2678 126 common/image.c Ramdisk subimage hash verification OK
2679 -126 common/image.c Ramdisk subimage for unsupported architecture
2680 127 common/image.c Architecture check OK
2681 -127 common/image.c Can't get ramdisk subimage data/size
2682 128 common/image.c Got ramdisk subimage data/size
2683 129 common/image.c Can't get ramdisk load address
2684 -129 common/image.c Got ramdisk load address
2686 -130 common/cmd_doc.c Incorrect FIT image format
2687 131 common/cmd_doc.c FIT image format OK
2689 -140 common/cmd_ide.c Incorrect FIT image format
2690 141 common/cmd_ide.c FIT image format OK
2692 -150 common/cmd_nand.c Incorrect FIT image format
2693 151 common/cmd_nand.c FIT image format OK
2695 - FIT image support:
2697 Enable support for the FIT uImage format.
2699 CONFIG_FIT_BEST_MATCH
2700 When no configuration is explicitly selected, default to the
2701 one whose fdt's compatibility field best matches that of
2702 U-Boot itself. A match is considered "best" if it matches the
2703 most specific compatibility entry of U-Boot's fdt's root node.
2704 The order of entries in the configuration's fdt is ignored.
2706 - Standalone program support:
2707 CONFIG_STANDALONE_LOAD_ADDR
2709 This option defines a board specific value for the
2710 address where standalone program gets loaded, thus
2711 overwriting the architecture dependent default
2714 - Frame Buffer Address:
2717 Define CONFIG_FB_ADDR if you want to use specific
2718 address for frame buffer. This is typically the case
2719 when using a graphics controller has separate video
2720 memory. U-Boot will then place the frame buffer at
2721 the given address instead of dynamically reserving it
2722 in system RAM by calling lcd_setmem(), which grabs
2723 the memory for the frame buffer depending on the
2724 configured panel size.
2726 Please see board_init_f function.
2728 - Automatic software updates via TFTP server
2730 CONFIG_UPDATE_TFTP_CNT_MAX
2731 CONFIG_UPDATE_TFTP_MSEC_MAX
2733 These options enable and control the auto-update feature;
2734 for a more detailed description refer to doc/README.update.
2736 - MTD Support (mtdparts command, UBI support)
2739 Adds the MTD device infrastructure from the Linux kernel.
2740 Needed for mtdparts command support.
2742 CONFIG_MTD_PARTITIONS
2744 Adds the MTD partitioning infrastructure from the Linux
2745 kernel. Needed for UBI support.
2749 Enable building of SPL globally.
2752 LDSCRIPT for linking the SPL binary.
2755 Maximum binary size (text, data and rodata) of the SPL binary.
2757 CONFIG_SPL_TEXT_BASE
2758 TEXT_BASE for linking the SPL binary.
2760 CONFIG_SPL_RELOC_TEXT_BASE
2761 Address to relocate to. If unspecified, this is equal to
2762 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2764 CONFIG_SPL_BSS_START_ADDR
2765 Link address for the BSS within the SPL binary.
2767 CONFIG_SPL_BSS_MAX_SIZE
2768 Maximum binary size of the BSS section of the SPL binary.
2771 Adress of the start of the stack SPL will use
2773 CONFIG_SPL_RELOC_STACK
2774 Adress of the start of the stack SPL will use after
2775 relocation. If unspecified, this is equal to
2778 CONFIG_SYS_SPL_MALLOC_START
2779 Starting address of the malloc pool used in SPL.
2781 CONFIG_SYS_SPL_MALLOC_SIZE
2782 The size of the malloc pool used in SPL.
2784 CONFIG_SPL_FRAMEWORK
2785 Enable the SPL framework under common/. This framework
2786 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2787 NAND loading of the Linux Kernel.
2789 CONFIG_SPL_DISPLAY_PRINT
2790 For ARM, enable an optional function to print more information
2791 about the running system.
2793 CONFIG_SPL_INIT_MINIMAL
2794 Arch init code should be built for a very small image
2796 CONFIG_SPL_LIBCOMMON_SUPPORT
2797 Support for common/libcommon.o in SPL binary
2799 CONFIG_SPL_LIBDISK_SUPPORT
2800 Support for disk/libdisk.o in SPL binary
2802 CONFIG_SPL_I2C_SUPPORT
2803 Support for drivers/i2c/libi2c.o in SPL binary
2805 CONFIG_SPL_GPIO_SUPPORT
2806 Support for drivers/gpio/libgpio.o in SPL binary
2808 CONFIG_SPL_MMC_SUPPORT
2809 Support for drivers/mmc/libmmc.o in SPL binary
2811 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2812 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2813 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2814 Address, size and partition on the MMC to load U-Boot from
2815 when the MMC is being used in raw mode.
2817 CONFIG_SPL_FAT_SUPPORT
2818 Support for fs/fat/libfat.o in SPL binary
2820 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2821 Filename to read to load U-Boot when reading from FAT
2823 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2824 Set this for NAND SPL on PPC mpc83xx targets, so that
2825 start.S waits for the rest of the SPL to load before
2826 continuing (the hardware starts execution after just
2827 loading the first page rather than the full 4K).
2829 CONFIG_SPL_NAND_BASE
2830 Include nand_base.c in the SPL. Requires
2831 CONFIG_SPL_NAND_DRIVERS.
2833 CONFIG_SPL_NAND_DRIVERS
2834 SPL uses normal NAND drivers, not minimal drivers.
2837 Include standard software ECC in the SPL
2839 CONFIG_SPL_NAND_SIMPLE
2840 Support for NAND boot using simple NAND drivers that
2841 expose the cmd_ctrl() interface.
2843 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2844 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2845 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2846 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2847 CONFIG_SYS_NAND_ECCBYTES
2848 Defines the size and behavior of the NAND that SPL uses
2851 CONFIG_SYS_NAND_U_BOOT_OFFS
2852 Location in NAND to read U-Boot from
2854 CONFIG_SYS_NAND_U_BOOT_DST
2855 Location in memory to load U-Boot to
2857 CONFIG_SYS_NAND_U_BOOT_SIZE
2858 Size of image to load
2860 CONFIG_SYS_NAND_U_BOOT_START
2861 Entry point in loaded image to jump to
2863 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2864 Define this if you need to first read the OOB and then the
2865 data. This is used for example on davinci plattforms.
2867 CONFIG_SPL_OMAP3_ID_NAND
2868 Support for an OMAP3-specific set of functions to return the
2869 ID and MFR of the first attached NAND chip, if present.
2871 CONFIG_SPL_SERIAL_SUPPORT
2872 Support for drivers/serial/libserial.o in SPL binary
2874 CONFIG_SPL_SPI_FLASH_SUPPORT
2875 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2877 CONFIG_SPL_SPI_SUPPORT
2878 Support for drivers/spi/libspi.o in SPL binary
2880 CONFIG_SPL_RAM_DEVICE
2881 Support for running image already present in ram, in SPL binary
2883 CONFIG_SPL_LIBGENERIC_SUPPORT
2884 Support for lib/libgeneric.o in SPL binary
2887 Linker address to which the SPL should be padded before
2888 appending the SPL payload.
2891 Final target image containing SPL and payload. Some SPLs
2892 use an arch-specific makefile fragment instead, for
2893 example if more than one image needs to be produced.
2898 [so far only for SMDK2400 boards]
2900 - Modem support enable:
2901 CONFIG_MODEM_SUPPORT
2903 - RTS/CTS Flow control enable:
2906 - Modem debug support:
2907 CONFIG_MODEM_SUPPORT_DEBUG
2909 Enables debugging stuff (char screen[1024], dbg())
2910 for modem support. Useful only with BDI2000.
2912 - Interrupt support (PPC):
2914 There are common interrupt_init() and timer_interrupt()
2915 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2916 for CPU specific initialization. interrupt_init_cpu()
2917 should set decrementer_count to appropriate value. If
2918 CPU resets decrementer automatically after interrupt
2919 (ppc4xx) it should set decrementer_count to zero.
2920 timer_interrupt() calls timer_interrupt_cpu() for CPU
2921 specific handling. If board has watchdog / status_led
2922 / other_activity_monitor it works automatically from
2923 general timer_interrupt().
2927 In the target system modem support is enabled when a
2928 specific key (key combination) is pressed during
2929 power-on. Otherwise U-Boot will boot normally
2930 (autoboot). The key_pressed() function is called from
2931 board_init(). Currently key_pressed() is a dummy
2932 function, returning 1 and thus enabling modem
2935 If there are no modem init strings in the
2936 environment, U-Boot proceed to autoboot; the
2937 previous output (banner, info printfs) will be
2940 See also: doc/README.Modem
2942 Board initialization settings:
2943 ------------------------------
2945 During Initialization u-boot calls a number of board specific functions
2946 to allow the preparation of board specific prerequisites, e.g. pin setup
2947 before drivers are initialized. To enable these callbacks the
2948 following configuration macros have to be defined. Currently this is
2949 architecture specific, so please check arch/your_architecture/lib/board.c
2950 typically in board_init_f() and board_init_r().
2952 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2953 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2954 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2955 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2957 Configuration Settings:
2958 -----------------------
2960 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2961 undefine this when you're short of memory.
2963 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2964 width of the commands listed in the 'help' command output.
2966 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2967 prompt for user input.
2969 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2971 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2973 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2975 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2976 the application (usually a Linux kernel) when it is
2979 - CONFIG_SYS_BAUDRATE_TABLE:
2980 List of legal baudrate settings for this board.
2982 - CONFIG_SYS_CONSOLE_INFO_QUIET
2983 Suppress display of console information at boot.
2985 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2986 If the board specific function
2987 extern int overwrite_console (void);
2988 returns 1, the stdin, stderr and stdout are switched to the
2989 serial port, else the settings in the environment are used.
2991 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2992 Enable the call to overwrite_console().
2994 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2995 Enable overwrite of previous console environment settings.
2997 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2998 Begin and End addresses of the area used by the
3001 - CONFIG_SYS_ALT_MEMTEST:
3002 Enable an alternate, more extensive memory test.
3004 - CONFIG_SYS_MEMTEST_SCRATCH:
3005 Scratch address used by the alternate memory test
3006 You only need to set this if address zero isn't writeable
3008 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3009 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3010 this specified memory area will get subtracted from the top
3011 (end) of RAM and won't get "touched" at all by U-Boot. By
3012 fixing up gd->ram_size the Linux kernel should gets passed
3013 the now "corrected" memory size and won't touch it either.
3014 This should work for arch/ppc and arch/powerpc. Only Linux
3015 board ports in arch/powerpc with bootwrapper support that
3016 recalculate the memory size from the SDRAM controller setup
3017 will have to get fixed in Linux additionally.
3019 This option can be used as a workaround for the 440EPx/GRx
3020 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3023 WARNING: Please make sure that this value is a multiple of
3024 the Linux page size (normally 4k). If this is not the case,
3025 then the end address of the Linux memory will be located at a
3026 non page size aligned address and this could cause major
3029 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3030 Enable temporary baudrate change while serial download
3032 - CONFIG_SYS_SDRAM_BASE:
3033 Physical start address of SDRAM. _Must_ be 0 here.
3035 - CONFIG_SYS_MBIO_BASE:
3036 Physical start address of Motherboard I/O (if using a
3039 - CONFIG_SYS_FLASH_BASE:
3040 Physical start address of Flash memory.
3042 - CONFIG_SYS_MONITOR_BASE:
3043 Physical start address of boot monitor code (set by
3044 make config files to be same as the text base address
3045 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3046 CONFIG_SYS_FLASH_BASE when booting from flash.
3048 - CONFIG_SYS_MONITOR_LEN:
3049 Size of memory reserved for monitor code, used to
3050 determine _at_compile_time_ (!) if the environment is
3051 embedded within the U-Boot image, or in a separate
3054 - CONFIG_SYS_MALLOC_LEN:
3055 Size of DRAM reserved for malloc() use.
3057 - CONFIG_SYS_BOOTM_LEN:
3058 Normally compressed uImages are limited to an
3059 uncompressed size of 8 MBytes. If this is not enough,
3060 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3061 to adjust this setting to your needs.
3063 - CONFIG_SYS_BOOTMAPSZ:
3064 Maximum size of memory mapped by the startup code of
3065 the Linux kernel; all data that must be processed by
3066 the Linux kernel (bd_info, boot arguments, FDT blob if
3067 used) must be put below this limit, unless "bootm_low"
3068 enviroment variable is defined and non-zero. In such case
3069 all data for the Linux kernel must be between "bootm_low"
3070 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3071 variable "bootm_mapsize" will override the value of
3072 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3073 then the value in "bootm_size" will be used instead.
3075 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3076 Enable initrd_high functionality. If defined then the
3077 initrd_high feature is enabled and the bootm ramdisk subcommand
3080 - CONFIG_SYS_BOOT_GET_CMDLINE:
3081 Enables allocating and saving kernel cmdline in space between
3082 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3084 - CONFIG_SYS_BOOT_GET_KBD:
3085 Enables allocating and saving a kernel copy of the bd_info in
3086 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3088 - CONFIG_SYS_MAX_FLASH_BANKS:
3089 Max number of Flash memory banks
3091 - CONFIG_SYS_MAX_FLASH_SECT:
3092 Max number of sectors on a Flash chip
3094 - CONFIG_SYS_FLASH_ERASE_TOUT:
3095 Timeout for Flash erase operations (in ms)
3097 - CONFIG_SYS_FLASH_WRITE_TOUT:
3098 Timeout for Flash write operations (in ms)
3100 - CONFIG_SYS_FLASH_LOCK_TOUT
3101 Timeout for Flash set sector lock bit operation (in ms)
3103 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3104 Timeout for Flash clear lock bits operation (in ms)
3106 - CONFIG_SYS_FLASH_PROTECTION
3107 If defined, hardware flash sectors protection is used
3108 instead of U-Boot software protection.
3110 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3112 Enable TFTP transfers directly to flash memory;
3113 without this option such a download has to be
3114 performed in two steps: (1) download to RAM, and (2)
3115 copy from RAM to flash.
3117 The two-step approach is usually more reliable, since
3118 you can check if the download worked before you erase
3119 the flash, but in some situations (when system RAM is
3120 too limited to allow for a temporary copy of the
3121 downloaded image) this option may be very useful.
3123 - CONFIG_SYS_FLASH_CFI:
3124 Define if the flash driver uses extra elements in the
3125 common flash structure for storing flash geometry.
3127 - CONFIG_FLASH_CFI_DRIVER
3128 This option also enables the building of the cfi_flash driver
3129 in the drivers directory
3131 - CONFIG_FLASH_CFI_MTD
3132 This option enables the building of the cfi_mtd driver
3133 in the drivers directory. The driver exports CFI flash
3136 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3137 Use buffered writes to flash.
3139 - CONFIG_FLASH_SPANSION_S29WS_N
3140 s29ws-n MirrorBit flash has non-standard addresses for buffered
3143 - CONFIG_SYS_FLASH_QUIET_TEST
3144 If this option is defined, the common CFI flash doesn't
3145 print it's warning upon not recognized FLASH banks. This
3146 is useful, if some of the configured banks are only
3147 optionally available.
3149 - CONFIG_FLASH_SHOW_PROGRESS
3150 If defined (must be an integer), print out countdown
3151 digits and dots. Recommended value: 45 (9..1) for 80
3152 column displays, 15 (3..1) for 40 column displays.
3154 - CONFIG_SYS_RX_ETH_BUFFER:
3155 Defines the number of Ethernet receive buffers. On some
3156 Ethernet controllers it is recommended to set this value
3157 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3158 buffers can be full shortly after enabling the interface
3159 on high Ethernet traffic.
3160 Defaults to 4 if not defined.
3162 - CONFIG_ENV_MAX_ENTRIES
3164 Maximum number of entries in the hash table that is used
3165 internally to store the environment settings. The default
3166 setting is supposed to be generous and should work in most
3167 cases. This setting can be used to tune behaviour; see
3168 lib/hashtable.c for details.
3170 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3171 - CONFIG_ENV_FLAGS_LIST_STATIC
3172 Enable validation of the values given to enviroment variables when
3173 calling env set. Variables can be restricted to only decimal,
3174 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3175 the variables can also be restricted to IP address or MAC address.
3177 The format of the list is:
3178 type_attribute = [s|d|x|b|i|m]
3179 access_atribute = [a|r|o|c]
3180 attributes = type_attribute[access_atribute]
3181 entry = variable_name[:attributes]
3184 The type attributes are:
3185 s - String (default)
3188 b - Boolean ([1yYtT|0nNfF])
3192 The access attributes are:
3198 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3199 Define this to a list (string) to define the ".flags"
3200 envirnoment variable in the default or embedded environment.
3202 - CONFIG_ENV_FLAGS_LIST_STATIC
3203 Define this to a list (string) to define validation that
3204 should be done if an entry is not found in the ".flags"
3205 environment variable. To override a setting in the static
3206 list, simply add an entry for the same variable name to the
3209 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3210 If defined, don't allow the -f switch to env set override variable
3213 The following definitions that deal with the placement and management
3214 of environment data (variable area); in general, we support the
3215 following configurations:
3217 - CONFIG_BUILD_ENVCRC:
3219 Builds up envcrc with the target environment so that external utils
3220 may easily extract it and embed it in final U-Boot images.
3222 - CONFIG_ENV_IS_IN_FLASH:
3224 Define this if the environment is in flash memory.
3226 a) The environment occupies one whole flash sector, which is
3227 "embedded" in the text segment with the U-Boot code. This
3228 happens usually with "bottom boot sector" or "top boot
3229 sector" type flash chips, which have several smaller
3230 sectors at the start or the end. For instance, such a
3231 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3232 such a case you would place the environment in one of the
3233 4 kB sectors - with U-Boot code before and after it. With
3234 "top boot sector" type flash chips, you would put the
3235 environment in one of the last sectors, leaving a gap
3236 between U-Boot and the environment.
3238 - CONFIG_ENV_OFFSET:
3240 Offset of environment data (variable area) to the
3241 beginning of flash memory; for instance, with bottom boot
3242 type flash chips the second sector can be used: the offset
3243 for this sector is given here.
3245 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3249 This is just another way to specify the start address of
3250 the flash sector containing the environment (instead of
3253 - CONFIG_ENV_SECT_SIZE:
3255 Size of the sector containing the environment.
3258 b) Sometimes flash chips have few, equal sized, BIG sectors.
3259 In such a case you don't want to spend a whole sector for
3264 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3265 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3266 of this flash sector for the environment. This saves
3267 memory for the RAM copy of the environment.
3269 It may also save flash memory if you decide to use this
3270 when your environment is "embedded" within U-Boot code,
3271 since then the remainder of the flash sector could be used
3272 for U-Boot code. It should be pointed out that this is
3273 STRONGLY DISCOURAGED from a robustness point of view:
3274 updating the environment in flash makes it always
3275 necessary to erase the WHOLE sector. If something goes
3276 wrong before the contents has been restored from a copy in
3277 RAM, your target system will be dead.
3279 - CONFIG_ENV_ADDR_REDUND
3280 CONFIG_ENV_SIZE_REDUND
3282 These settings describe a second storage area used to hold
3283 a redundant copy of the environment data, so that there is
3284 a valid backup copy in case there is a power failure during
3285 a "saveenv" operation.
3287 BE CAREFUL! Any changes to the flash layout, and some changes to the
3288 source code will make it necessary to adapt <board>/u-boot.lds*
3292 - CONFIG_ENV_IS_IN_NVRAM:
3294 Define this if you have some non-volatile memory device
3295 (NVRAM, battery buffered SRAM) which you want to use for the
3301 These two #defines are used to determine the memory area you
3302 want to use for environment. It is assumed that this memory
3303 can just be read and written to, without any special
3306 BE CAREFUL! The first access to the environment happens quite early
3307 in U-Boot initalization (when we try to get the setting of for the
3308 console baudrate). You *MUST* have mapped your NVRAM area then, or
3311 Please note that even with NVRAM we still use a copy of the
3312 environment in RAM: we could work on NVRAM directly, but we want to
3313 keep settings there always unmodified except somebody uses "saveenv"
3314 to save the current settings.
3317 - CONFIG_ENV_IS_IN_EEPROM:
3319 Use this if you have an EEPROM or similar serial access
3320 device and a driver for it.
3322 - CONFIG_ENV_OFFSET:
3325 These two #defines specify the offset and size of the
3326 environment area within the total memory of your EEPROM.
3328 - CONFIG_SYS_I2C_EEPROM_ADDR:
3329 If defined, specified the chip address of the EEPROM device.
3330 The default address is zero.
3332 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3333 If defined, the number of bits used to address bytes in a
3334 single page in the EEPROM device. A 64 byte page, for example
3335 would require six bits.
3337 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3338 If defined, the number of milliseconds to delay between
3339 page writes. The default is zero milliseconds.
3341 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3342 The length in bytes of the EEPROM memory array address. Note
3343 that this is NOT the chip address length!
3345 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3346 EEPROM chips that implement "address overflow" are ones
3347 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3348 address and the extra bits end up in the "chip address" bit
3349 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3352 Note that we consider the length of the address field to
3353 still be one byte because the extra address bits are hidden
3354 in the chip address.
3356 - CONFIG_SYS_EEPROM_SIZE:
3357 The size in bytes of the EEPROM device.
3359 - CONFIG_ENV_EEPROM_IS_ON_I2C
3360 define this, if you have I2C and SPI activated, and your
3361 EEPROM, which holds the environment, is on the I2C bus.
3363 - CONFIG_I2C_ENV_EEPROM_BUS
3364 if you have an Environment on an EEPROM reached over
3365 I2C muxes, you can define here, how to reach this
3366 EEPROM. For example:
3368 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3370 EEPROM which holds the environment, is reached over
3371 a pca9547 i2c mux with address 0x70, channel 3.
3373 - CONFIG_ENV_IS_IN_DATAFLASH:
3375 Define this if you have a DataFlash memory device which you
3376 want to use for the environment.
3378 - CONFIG_ENV_OFFSET:
3382 These three #defines specify the offset and size of the
3383 environment area within the total memory of your DataFlash placed
3384 at the specified address.
3386 - CONFIG_ENV_IS_IN_REMOTE:
3388 Define this if you have a remote memory space which you
3389 want to use for the local device's environment.
3394 These two #defines specify the address and size of the
3395 environment area within the remote memory space. The
3396 local device can get the environment from remote memory
3397 space by SRIO or PCIE links.
3399 BE CAREFUL! For some special cases, the local device can not use
3400 "saveenv" command. For example, the local device will get the
3401 environment stored in a remote NOR flash by SRIO or PCIE link,
3402 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3404 - CONFIG_ENV_IS_IN_NAND:
3406 Define this if you have a NAND device which you want to use
3407 for the environment.
3409 - CONFIG_ENV_OFFSET:
3412 These two #defines specify the offset and size of the environment
3413 area within the first NAND device. CONFIG_ENV_OFFSET must be
3414 aligned to an erase block boundary.
3416 - CONFIG_ENV_OFFSET_REDUND (optional):
3418 This setting describes a second storage area of CONFIG_ENV_SIZE
3419 size used to hold a redundant copy of the environment data, so
3420 that there is a valid backup copy in case there is a power failure
3421 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3422 aligned to an erase block boundary.
3424 - CONFIG_ENV_RANGE (optional):
3426 Specifies the length of the region in which the environment
3427 can be written. This should be a multiple of the NAND device's
3428 block size. Specifying a range with more erase blocks than
3429 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3430 the range to be avoided.
3432 - CONFIG_ENV_OFFSET_OOB (optional):
3434 Enables support for dynamically retrieving the offset of the
3435 environment from block zero's out-of-band data. The
3436 "nand env.oob" command can be used to record this offset.
3437 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3438 using CONFIG_ENV_OFFSET_OOB.
3440 - CONFIG_NAND_ENV_DST
3442 Defines address in RAM to which the nand_spl code should copy the
3443 environment. If redundant environment is used, it will be copied to
3444 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3446 - CONFIG_SYS_SPI_INIT_OFFSET
3448 Defines offset to the initial SPI buffer area in DPRAM. The
3449 area is used at an early stage (ROM part) if the environment
3450 is configured to reside in the SPI EEPROM: We need a 520 byte
3451 scratch DPRAM area. It is used between the two initialization
3452 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3453 to be a good choice since it makes it far enough from the
3454 start of the data area as well as from the stack pointer.
3456 Please note that the environment is read-only until the monitor
3457 has been relocated to RAM and a RAM copy of the environment has been
3458 created; also, when using EEPROM you will have to use getenv_f()
3459 until then to read environment variables.
3461 The environment is protected by a CRC32 checksum. Before the monitor
3462 is relocated into RAM, as a result of a bad CRC you will be working
3463 with the compiled-in default environment - *silently*!!! [This is
3464 necessary, because the first environment variable we need is the
3465 "baudrate" setting for the console - if we have a bad CRC, we don't
3466 have any device yet where we could complain.]
3468 Note: once the monitor has been relocated, then it will complain if
3469 the default environment is used; a new CRC is computed as soon as you
3470 use the "saveenv" command to store a valid environment.
3472 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3473 Echo the inverted Ethernet link state to the fault LED.
3475 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3476 also needs to be defined.
3478 - CONFIG_SYS_FAULT_MII_ADDR:
3479 MII address of the PHY to check for the Ethernet link state.
3481 - CONFIG_NS16550_MIN_FUNCTIONS:
3482 Define this if you desire to only have use of the NS16550_init
3483 and NS16550_putc functions for the serial driver located at
3484 drivers/serial/ns16550.c. This option is useful for saving
3485 space for already greatly restricted images, including but not
3486 limited to NAND_SPL configurations.
3488 - CONFIG_DISPLAY_BOARDINFO
3489 Display information about the board that U-Boot is running on
3490 when U-Boot starts up. The board function checkboard() is called
3493 - CONFIG_DISPLAY_BOARDINFO_LATE
3494 Similar to the previous option, but display this information
3495 later, once stdio is running and output goes to the LCD, if
3498 Low Level (hardware related) configuration options:
3499 ---------------------------------------------------
3501 - CONFIG_SYS_CACHELINE_SIZE:
3502 Cache Line Size of the CPU.
3504 - CONFIG_SYS_DEFAULT_IMMR:
3505 Default address of the IMMR after system reset.
3507 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3508 and RPXsuper) to be able to adjust the position of
3509 the IMMR register after a reset.
3511 - CONFIG_SYS_CCSRBAR_DEFAULT:
3512 Default (power-on reset) physical address of CCSR on Freescale
3515 - CONFIG_SYS_CCSRBAR:
3516 Virtual address of CCSR. On a 32-bit build, this is typically
3517 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3519 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3520 for cross-platform code that uses that macro instead.
3522 - CONFIG_SYS_CCSRBAR_PHYS:
3523 Physical address of CCSR. CCSR can be relocated to a new
3524 physical address, if desired. In this case, this macro should
3525 be set to that address. Otherwise, it should be set to the
3526 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3527 is typically relocated on 36-bit builds. It is recommended
3528 that this macro be defined via the _HIGH and _LOW macros:
3530 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3531 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3533 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3534 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3535 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3536 used in assembly code, so it must not contain typecasts or
3537 integer size suffixes (e.g. "ULL").
3539 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3540 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3541 used in assembly code, so it must not contain typecasts or
3542 integer size suffixes (e.g. "ULL").
3544 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3545 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3546 forced to a value that ensures that CCSR is not relocated.
3548 - Floppy Disk Support:
3549 CONFIG_SYS_FDC_DRIVE_NUMBER
3551 the default drive number (default value 0)
3553 CONFIG_SYS_ISA_IO_STRIDE
3555 defines the spacing between FDC chipset registers
3558 CONFIG_SYS_ISA_IO_OFFSET
3560 defines the offset of register from address. It
3561 depends on which part of the data bus is connected to
3562 the FDC chipset. (default value 0)
3564 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3565 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3568 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3569 fdc_hw_init() is called at the beginning of the FDC
3570 setup. fdc_hw_init() must be provided by the board
3571 source code. It is used to make hardware dependant
3575 Most IDE controllers were designed to be connected with PCI
3576 interface. Only few of them were designed for AHB interface.
3577 When software is doing ATA command and data transfer to
3578 IDE devices through IDE-AHB controller, some additional
3579 registers accessing to these kind of IDE-AHB controller
3582 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3583 DO NOT CHANGE unless you know exactly what you're
3584 doing! (11-4) [MPC8xx/82xx systems only]
3586 - CONFIG_SYS_INIT_RAM_ADDR:
3588 Start address of memory area that can be used for
3589 initial data and stack; please note that this must be
3590 writable memory that is working WITHOUT special
3591 initialization, i. e. you CANNOT use normal RAM which
3592 will become available only after programming the
3593 memory controller and running certain initialization
3596 U-Boot uses the following memory types:
3597 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3598 - MPC824X: data cache
3599 - PPC4xx: data cache
3601 - CONFIG_SYS_GBL_DATA_OFFSET:
3603 Offset of the initial data structure in the memory
3604 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3605 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3606 data is located at the end of the available space
3607 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3608 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3609 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3610 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3613 On the MPC824X (or other systems that use the data
3614 cache for initial memory) the address chosen for
3615 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3616 point to an otherwise UNUSED address space between
3617 the top of RAM and the start of the PCI space.
3619 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3621 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3623 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3625 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3627 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3629 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3631 - CONFIG_SYS_OR_TIMING_SDRAM:
3634 - CONFIG_SYS_MAMR_PTA:
3635 periodic timer for refresh
3637 - CONFIG_SYS_DER: Debug Event Register (37-47)
3639 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3640 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3641 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3642 CONFIG_SYS_BR1_PRELIM:
3643 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3645 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3646 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3647 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3648 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3650 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3651 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3652 Machine Mode Register and Memory Periodic Timer
3653 Prescaler definitions (SDRAM timing)
3655 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3656 enable I2C microcode relocation patch (MPC8xx);
3657 define relocation offset in DPRAM [DSP2]
3659 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3660 enable SMC microcode relocation patch (MPC8xx);
3661 define relocation offset in DPRAM [SMC1]
3663 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3664 enable SPI microcode relocation patch (MPC8xx);
3665 define relocation offset in DPRAM [SCC4]
3667 - CONFIG_SYS_USE_OSCCLK:
3668 Use OSCM clock mode on MBX8xx board. Be careful,
3669 wrong setting might damage your board. Read
3670 doc/README.MBX before setting this variable!
3672 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3673 Offset of the bootmode word in DPRAM used by post
3674 (Power On Self Tests). This definition overrides
3675 #define'd default value in commproc.h resp.
3678 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3679 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3680 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3681 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3682 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3683 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3684 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3685 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3686 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3688 - CONFIG_PCI_DISABLE_PCIE:
3689 Disable PCI-Express on systems where it is supported but not
3692 - CONFIG_PCI_ENUM_ONLY
3693 Only scan through and get the devices on the busses.
3694 Don't do any setup work, presumably because someone or
3695 something has already done it, and we don't need to do it
3696 a second time. Useful for platforms that are pre-booted
3697 by coreboot or similar.
3700 Chip has SRIO or not
3703 Board has SRIO 1 port available
3706 Board has SRIO 2 port available
3708 - CONFIG_SYS_SRIOn_MEM_VIRT:
3709 Virtual Address of SRIO port 'n' memory region
3711 - CONFIG_SYS_SRIOn_MEM_PHYS:
3712 Physical Address of SRIO port 'n' memory region
3714 - CONFIG_SYS_SRIOn_MEM_SIZE:
3715 Size of SRIO port 'n' memory region
3717 - CONFIG_SYS_NDFC_16
3718 Defined to tell the NDFC that the NAND chip is using a
3721 - CONFIG_SYS_NDFC_EBC0_CFG
3722 Sets the EBC0_CFG register for the NDFC. If not defined
3723 a default value will be used.
3726 Get DDR timing information from an I2C EEPROM. Common
3727 with pluggable memory modules such as SODIMMs
3730 I2C address of the SPD EEPROM
3732 - CONFIG_SYS_SPD_BUS_NUM
3733 If SPD EEPROM is on an I2C bus other than the first
3734 one, specify here. Note that the value must resolve
3735 to something your driver can deal with.
3737 - CONFIG_SYS_DDR_RAW_TIMING
3738 Get DDR timing information from other than SPD. Common with
3739 soldered DDR chips onboard without SPD. DDR raw timing
3740 parameters are extracted from datasheet and hard-coded into
3741 header files or board specific files.
3743 - CONFIG_FSL_DDR_INTERACTIVE
3744 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3746 - CONFIG_SYS_83XX_DDR_USES_CS0
3747 Only for 83xx systems. If specified, then DDR should
3748 be configured using CS0 and CS1 instead of CS2 and CS3.
3750 - CONFIG_ETHER_ON_FEC[12]
3751 Define to enable FEC[12] on a 8xx series processor.
3753 - CONFIG_FEC[12]_PHY
3754 Define to the hardcoded PHY address which corresponds
3755 to the given FEC; i. e.
3756 #define CONFIG_FEC1_PHY 4
3757 means that the PHY with address 4 is connected to FEC1
3759 When set to -1, means to probe for first available.
3761 - CONFIG_FEC[12]_PHY_NORXERR
3762 The PHY does not have a RXERR line (RMII only).
3763 (so program the FEC to ignore it).
3766 Enable RMII mode for all FECs.
3767 Note that this is a global option, we can't
3768 have one FEC in standard MII mode and another in RMII mode.
3770 - CONFIG_CRC32_VERIFY
3771 Add a verify option to the crc32 command.
3774 => crc32 -v <address> <count> <crc32>
3776 Where address/count indicate a memory area
3777 and crc32 is the correct crc32 which the
3781 Add the "loopw" memory command. This only takes effect if
3782 the memory commands are activated globally (CONFIG_CMD_MEM).
3785 Add the "mdc" and "mwc" memory commands. These are cyclic
3790 This command will print 4 bytes (10,11,12,13) each 500 ms.
3792 => mwc.l 100 12345678 10
3793 This command will write 12345678 to address 100 all 10 ms.
3795 This only takes effect if the memory commands are activated
3796 globally (CONFIG_CMD_MEM).
3798 - CONFIG_SKIP_LOWLEVEL_INIT
3799 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3800 low level initializations (like setting up the memory
3801 controller) are omitted and/or U-Boot does not
3802 relocate itself into RAM.
3804 Normally this variable MUST NOT be defined. The only
3805 exception is when U-Boot is loaded (to RAM) by some
3806 other boot loader or by a debugger which performs
3807 these initializations itself.
3810 Modifies the behaviour of start.S when compiling a loader
3811 that is executed before the actual U-Boot. E.g. when
3812 compiling a NAND SPL.
3814 - CONFIG_USE_ARCH_MEMCPY
3815 CONFIG_USE_ARCH_MEMSET
3816 If these options are used a optimized version of memcpy/memset will
3817 be used if available. These functions may be faster under some
3818 conditions but may increase the binary size.
3820 - CONFIG_X86_RESET_VECTOR
3821 If defined, the x86 reset vector code is included. This is not
3822 needed when U-Boot is running from Coreboot.
3825 Freescale QE/FMAN Firmware Support:
3826 -----------------------------------
3828 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3829 loading of "firmware", which is encoded in the QE firmware binary format.
3830 This firmware often needs to be loaded during U-Boot booting, so macros
3831 are used to identify the storage device (NOR flash, SPI, etc) and the address
3834 - CONFIG_SYS_QE_FMAN_FW_ADDR
3835 The address in the storage device where the firmware is located. The
3836 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3839 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3840 The maximum possible size of the firmware. The firmware binary format
3841 has a field that specifies the actual size of the firmware, but it
3842 might not be possible to read any part of the firmware unless some
3843 local storage is allocated to hold the entire firmware first.
3845 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3846 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3847 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3848 virtual address in NOR flash.
3850 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3851 Specifies that QE/FMAN firmware is located in NAND flash.
3852 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3854 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3855 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3856 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3858 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3859 Specifies that QE/FMAN firmware is located on the primary SPI
3860 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3862 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3863 Specifies that QE/FMAN firmware is located in the remote (master)
3864 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3865 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3866 window->master inbound window->master LAW->the ucode address in
3867 master's memory space.
3869 Building the Software:
3870 ======================
3872 Building U-Boot has been tested in several native build environments
3873 and in many different cross environments. Of course we cannot support
3874 all possibly existing versions of cross development tools in all
3875 (potentially obsolete) versions. In case of tool chain problems we
3876 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3877 which is extensively used to build and test U-Boot.
3879 If you are not using a native environment, it is assumed that you
3880 have GNU cross compiling tools available in your path. In this case,
3881 you must set the environment variable CROSS_COMPILE in your shell.
3882 Note that no changes to the Makefile or any other source files are
3883 necessary. For example using the ELDK on a 4xx CPU, please enter:
3885 $ CROSS_COMPILE=ppc_4xx-
3886 $ export CROSS_COMPILE
3888 Note: If you wish to generate Windows versions of the utilities in
3889 the tools directory you can use the MinGW toolchain
3890 (http://www.mingw.org). Set your HOST tools to the MinGW
3891 toolchain and execute 'make tools'. For example:
3893 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3895 Binaries such as tools/mkimage.exe will be created which can
3896 be executed on computers running Windows.
3898 U-Boot is intended to be simple to build. After installing the
3899 sources you must configure U-Boot for one specific board type. This
3904 where "NAME_config" is the name of one of the existing configu-
3905 rations; see boards.cfg for supported names.
3907 Note: for some board special configuration names may exist; check if
3908 additional information is available from the board vendor; for
3909 instance, the TQM823L systems are available without (standard)
3910 or with LCD support. You can select such additional "features"
3911 when choosing the configuration, i. e.
3914 - will configure for a plain TQM823L, i. e. no LCD support
3916 make TQM823L_LCD_config
3917 - will configure for a TQM823L with U-Boot console on LCD
3922 Finally, type "make all", and you should get some working U-Boot
3923 images ready for download to / installation on your system:
3925 - "u-boot.bin" is a raw binary image
3926 - "u-boot" is an image in ELF binary format
3927 - "u-boot.srec" is in Motorola S-Record format
3929 By default the build is performed locally and the objects are saved
3930 in the source directory. One of the two methods can be used to change
3931 this behavior and build U-Boot to some external directory:
3933 1. Add O= to the make command line invocations:
3935 make O=/tmp/build distclean
3936 make O=/tmp/build NAME_config
3937 make O=/tmp/build all
3939 2. Set environment variable BUILD_DIR to point to the desired location:
3941 export BUILD_DIR=/tmp/build
3946 Note that the command line "O=" setting overrides the BUILD_DIR environment
3950 Please be aware that the Makefiles assume you are using GNU make, so
3951 for instance on NetBSD you might need to use "gmake" instead of
3955 If the system board that you have is not listed, then you will need
3956 to port U-Boot to your hardware platform. To do this, follow these
3959 1. Add a new configuration option for your board to the toplevel
3960 "boards.cfg" file, using the existing entries as examples.
3961 Follow the instructions there to keep the boards in order.
3962 2. Create a new directory to hold your board specific code. Add any
3963 files you need. In your board directory, you will need at least
3964 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3965 3. Create a new configuration file "include/configs/<board>.h" for
3967 3. If you're porting U-Boot to a new CPU, then also create a new
3968 directory to hold your CPU specific code. Add any files you need.
3969 4. Run "make <board>_config" with your new name.
3970 5. Type "make", and you should get a working "u-boot.srec" file
3971 to be installed on your target system.
3972 6. Debug and solve any problems that might arise.
3973 [Of course, this last step is much harder than it sounds.]
3976 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3977 ==============================================================
3979 If you have modified U-Boot sources (for instance added a new board
3980 or support for new devices, a new CPU, etc.) you are expected to
3981 provide feedback to the other developers. The feedback normally takes
3982 the form of a "patch", i. e. a context diff against a certain (latest
3983 official or latest in the git repository) version of U-Boot sources.
3985 But before you submit such a patch, please verify that your modifi-
3986 cation did not break existing code. At least make sure that *ALL* of
3987 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3988 just run the "MAKEALL" script, which will configure and build U-Boot
3989 for ALL supported system. Be warned, this will take a while. You can
3990 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3991 environment variable to the script, i. e. to use the ELDK cross tools
3994 CROSS_COMPILE=ppc_8xx- MAKEALL
3996 or to build on a native PowerPC system you can type
3998 CROSS_COMPILE=' ' MAKEALL
4000 When using the MAKEALL script, the default behaviour is to build
4001 U-Boot in the source directory. This location can be changed by
4002 setting the BUILD_DIR environment variable. Also, for each target
4003 built, the MAKEALL script saves two log files (<target>.ERR and
4004 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4005 location can be changed by setting the MAKEALL_LOGDIR environment
4006 variable. For example:
4008 export BUILD_DIR=/tmp/build
4009 export MAKEALL_LOGDIR=/tmp/log
4010 CROSS_COMPILE=ppc_8xx- MAKEALL
4012 With the above settings build objects are saved in the /tmp/build,
4013 log files are saved in the /tmp/log and the source tree remains clean
4014 during the whole build process.
4017 See also "U-Boot Porting Guide" below.
4020 Monitor Commands - Overview:
4021 ============================
4023 go - start application at address 'addr'
4024 run - run commands in an environment variable
4025 bootm - boot application image from memory
4026 bootp - boot image via network using BootP/TFTP protocol
4027 bootz - boot zImage from memory
4028 tftpboot- boot image via network using TFTP protocol
4029 and env variables "ipaddr" and "serverip"
4030 (and eventually "gatewayip")
4031 tftpput - upload a file via network using TFTP protocol
4032 rarpboot- boot image via network using RARP/TFTP protocol
4033 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4034 loads - load S-Record file over serial line
4035 loadb - load binary file over serial line (kermit mode)
4037 mm - memory modify (auto-incrementing)
4038 nm - memory modify (constant address)
4039 mw - memory write (fill)
4041 cmp - memory compare
4042 crc32 - checksum calculation
4043 i2c - I2C sub-system
4044 sspi - SPI utility commands
4045 base - print or set address offset
4046 printenv- print environment variables
4047 setenv - set environment variables
4048 saveenv - save environment variables to persistent storage
4049 protect - enable or disable FLASH write protection
4050 erase - erase FLASH memory
4051 flinfo - print FLASH memory information
4052 nand - NAND memory operations (see doc/README.nand)
4053 bdinfo - print Board Info structure
4054 iminfo - print header information for application image
4055 coninfo - print console devices and informations
4056 ide - IDE sub-system
4057 loop - infinite loop on address range
4058 loopw - infinite write loop on address range
4059 mtest - simple RAM test
4060 icache - enable or disable instruction cache
4061 dcache - enable or disable data cache
4062 reset - Perform RESET of the CPU
4063 echo - echo args to console
4064 version - print monitor version
4065 help - print online help
4066 ? - alias for 'help'
4069 Monitor Commands - Detailed Description:
4070 ========================================
4074 For now: just type "help <command>".
4077 Environment Variables:
4078 ======================
4080 U-Boot supports user configuration using Environment Variables which
4081 can be made persistent by saving to Flash memory.
4083 Environment Variables are set using "setenv", printed using
4084 "printenv", and saved to Flash using "saveenv". Using "setenv"
4085 without a value can be used to delete a variable from the
4086 environment. As long as you don't save the environment you are
4087 working with an in-memory copy. In case the Flash area containing the
4088 environment is erased by accident, a default environment is provided.
4090 Some configuration options can be set using Environment Variables.
4092 List of environment variables (most likely not complete):
4094 baudrate - see CONFIG_BAUDRATE
4096 bootdelay - see CONFIG_BOOTDELAY
4098 bootcmd - see CONFIG_BOOTCOMMAND
4100 bootargs - Boot arguments when booting an RTOS image
4102 bootfile - Name of the image to load with TFTP
4104 bootm_low - Memory range available for image processing in the bootm
4105 command can be restricted. This variable is given as
4106 a hexadecimal number and defines lowest address allowed
4107 for use by the bootm command. See also "bootm_size"
4108 environment variable. Address defined by "bootm_low" is
4109 also the base of the initial memory mapping for the Linux
4110 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4113 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4114 This variable is given as a hexadecimal number and it
4115 defines the size of the memory region starting at base
4116 address bootm_low that is accessible by the Linux kernel
4117 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4118 as the default value if it is defined, and bootm_size is
4121 bootm_size - Memory range available for image processing in the bootm
4122 command can be restricted. This variable is given as
4123 a hexadecimal number and defines the size of the region
4124 allowed for use by the bootm command. See also "bootm_low"
4125 environment variable.
4127 updatefile - Location of the software update file on a TFTP server, used
4128 by the automatic software update feature. Please refer to
4129 documentation in doc/README.update for more details.
4131 autoload - if set to "no" (any string beginning with 'n'),
4132 "bootp" will just load perform a lookup of the
4133 configuration from the BOOTP server, but not try to
4134 load any image using TFTP
4136 autostart - if set to "yes", an image loaded using the "bootp",
4137 "rarpboot", "tftpboot" or "diskboot" commands will
4138 be automatically started (by internally calling
4141 If set to "no", a standalone image passed to the
4142 "bootm" command will be copied to the load address
4143 (and eventually uncompressed), but NOT be started.
4144 This can be used to load and uncompress arbitrary
4147 fdt_high - if set this restricts the maximum address that the
4148 flattened device tree will be copied into upon boot.
4149 For example, if you have a system with 1 GB memory
4150 at physical address 0x10000000, while Linux kernel
4151 only recognizes the first 704 MB as low memory, you
4152 may need to set fdt_high as 0x3C000000 to have the
4153 device tree blob be copied to the maximum address
4154 of the 704 MB low memory, so that Linux kernel can
4155 access it during the boot procedure.
4157 If this is set to the special value 0xFFFFFFFF then
4158 the fdt will not be copied at all on boot. For this
4159 to work it must reside in writable memory, have
4160 sufficient padding on the end of it for u-boot to
4161 add the information it needs into it, and the memory
4162 must be accessible by the kernel.
4164 fdtcontroladdr- if set this is the address of the control flattened
4165 device tree used by U-Boot when CONFIG_OF_CONTROL is
4168 i2cfast - (PPC405GP|PPC405EP only)
4169 if set to 'y' configures Linux I2C driver for fast
4170 mode (400kHZ). This environment variable is used in
4171 initialization code. So, for changes to be effective
4172 it must be saved and board must be reset.
4174 initrd_high - restrict positioning of initrd images:
4175 If this variable is not set, initrd images will be
4176 copied to the highest possible address in RAM; this
4177 is usually what you want since it allows for
4178 maximum initrd size. If for some reason you want to
4179 make sure that the initrd image is loaded below the
4180 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4181 variable to a value of "no" or "off" or "0".
4182 Alternatively, you can set it to a maximum upper
4183 address to use (U-Boot will still check that it
4184 does not overwrite the U-Boot stack and data).
4186 For instance, when you have a system with 16 MB
4187 RAM, and want to reserve 4 MB from use by Linux,
4188 you can do this by adding "mem=12M" to the value of
4189 the "bootargs" variable. However, now you must make
4190 sure that the initrd image is placed in the first
4191 12 MB as well - this can be done with
4193 setenv initrd_high 00c00000
4195 If you set initrd_high to 0xFFFFFFFF, this is an
4196 indication to U-Boot that all addresses are legal
4197 for the Linux kernel, including addresses in flash
4198 memory. In this case U-Boot will NOT COPY the
4199 ramdisk at all. This may be useful to reduce the
4200 boot time on your system, but requires that this
4201 feature is supported by your Linux kernel.
4203 ipaddr - IP address; needed for tftpboot command
4205 loadaddr - Default load address for commands like "bootp",
4206 "rarpboot", "tftpboot", "loadb" or "diskboot"
4208 loads_echo - see CONFIG_LOADS_ECHO
4210 serverip - TFTP server IP address; needed for tftpboot command
4212 bootretry - see CONFIG_BOOT_RETRY_TIME
4214 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4216 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4218 ethprime - controls which interface is used first.
4220 ethact - controls which interface is currently active.
4221 For example you can do the following
4223 => setenv ethact FEC
4224 => ping 192.168.0.1 # traffic sent on FEC
4225 => setenv ethact SCC
4226 => ping 10.0.0.1 # traffic sent on SCC
4228 ethrotate - When set to "no" U-Boot does not go through all
4229 available network interfaces.
4230 It just stays at the currently selected interface.
4232 netretry - When set to "no" each network operation will
4233 either succeed or fail without retrying.
4234 When set to "once" the network operation will
4235 fail when all the available network interfaces
4236 are tried once without success.
4237 Useful on scripts which control the retry operation
4240 npe_ucode - set load address for the NPE microcode
4242 tftpsrcport - If this is set, the value is used for TFTP's
4245 tftpdstport - If this is set, the value is used for TFTP's UDP
4246 destination port instead of the Well Know Port 69.
4248 tftpblocksize - Block size to use for TFTP transfers; if not set,
4249 we use the TFTP server's default block size
4251 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4252 seconds, minimum value is 1000 = 1 second). Defines
4253 when a packet is considered to be lost so it has to
4254 be retransmitted. The default is 5000 = 5 seconds.
4255 Lowering this value may make downloads succeed
4256 faster in networks with high packet loss rates or
4257 with unreliable TFTP servers.
4259 vlan - When set to a value < 4095 the traffic over
4260 Ethernet is encapsulated/received over 802.1q
4263 The following image location variables contain the location of images
4264 used in booting. The "Image" column gives the role of the image and is
4265 not an environment variable name. The other columns are environment
4266 variable names. "File Name" gives the name of the file on a TFTP
4267 server, "RAM Address" gives the location in RAM the image will be
4268 loaded to, and "Flash Location" gives the image's address in NOR
4269 flash or offset in NAND flash.
4271 *Note* - these variables don't have to be defined for all boards, some
4272 boards currenlty use other variables for these purposes, and some
4273 boards use these variables for other purposes.
4275 Image File Name RAM Address Flash Location
4276 ----- --------- ----------- --------------
4277 u-boot u-boot u-boot_addr_r u-boot_addr
4278 Linux kernel bootfile kernel_addr_r kernel_addr
4279 device tree blob fdtfile fdt_addr_r fdt_addr
4280 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4282 The following environment variables may be used and automatically
4283 updated by the network boot commands ("bootp" and "rarpboot"),
4284 depending the information provided by your boot server:
4286 bootfile - see above
4287 dnsip - IP address of your Domain Name Server
4288 dnsip2 - IP address of your secondary Domain Name Server
4289 gatewayip - IP address of the Gateway (Router) to use
4290 hostname - Target hostname
4292 netmask - Subnet Mask
4293 rootpath - Pathname of the root filesystem on the NFS server
4294 serverip - see above
4297 There are two special Environment Variables:
4299 serial# - contains hardware identification information such
4300 as type string and/or serial number
4301 ethaddr - Ethernet address
4303 These variables can be set only once (usually during manufacturing of
4304 the board). U-Boot refuses to delete or overwrite these variables
4305 once they have been set once.
4308 Further special Environment Variables:
4310 ver - Contains the U-Boot version string as printed
4311 with the "version" command. This variable is
4312 readonly (see CONFIG_VERSION_VARIABLE).
4315 Please note that changes to some configuration parameters may take
4316 only effect after the next boot (yes, that's just like Windoze :-).
4319 Callback functions for environment variables:
4320 ---------------------------------------------
4322 For some environment variables, the behavior of u-boot needs to change
4323 when their values are changed. This functionailty allows functions to
4324 be associated with arbitrary variables. On creation, overwrite, or
4325 deletion, the callback will provide the opportunity for some side
4326 effect to happen or for the change to be rejected.
4328 The callbacks are named and associated with a function using the
4329 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4331 These callbacks are associated with variables in one of two ways. The
4332 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4333 in the board configuration to a string that defines a list of
4334 associations. The list must be in the following format:
4336 entry = variable_name[:callback_name]
4339 If the callback name is not specified, then the callback is deleted.
4340 Spaces are also allowed anywhere in the list.
4342 Callbacks can also be associated by defining the ".callbacks" variable
4343 with the same list format above. Any association in ".callbacks" will
4344 override any association in the static list. You can define
4345 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4346 ".callbacks" envirnoment variable in the default or embedded environment.
4349 Command Line Parsing:
4350 =====================
4352 There are two different command line parsers available with U-Boot:
4353 the old "simple" one, and the much more powerful "hush" shell:
4355 Old, simple command line parser:
4356 --------------------------------
4358 - supports environment variables (through setenv / saveenv commands)
4359 - several commands on one line, separated by ';'
4360 - variable substitution using "... ${name} ..." syntax
4361 - special characters ('$', ';') can be escaped by prefixing with '\',
4363 setenv bootcmd bootm \${address}
4364 - You can also escape text by enclosing in single apostrophes, for example:
4365 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4370 - similar to Bourne shell, with control structures like
4371 if...then...else...fi, for...do...done; while...do...done,
4372 until...do...done, ...
4373 - supports environment ("global") variables (through setenv / saveenv
4374 commands) and local shell variables (through standard shell syntax
4375 "name=value"); only environment variables can be used with "run"
4381 (1) If a command line (or an environment variable executed by a "run"
4382 command) contains several commands separated by semicolon, and
4383 one of these commands fails, then the remaining commands will be
4386 (2) If you execute several variables with one call to run (i. e.
4387 calling run with a list of variables as arguments), any failing
4388 command will cause "run" to terminate, i. e. the remaining
4389 variables are not executed.
4391 Note for Redundant Ethernet Interfaces:
4392 =======================================
4394 Some boards come with redundant Ethernet interfaces; U-Boot supports
4395 such configurations and is capable of automatic selection of a
4396 "working" interface when needed. MAC assignment works as follows:
4398 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4399 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4400 "eth1addr" (=>eth1), "eth2addr", ...
4402 If the network interface stores some valid MAC address (for instance
4403 in SROM), this is used as default address if there is NO correspon-
4404 ding setting in the environment; if the corresponding environment
4405 variable is set, this overrides the settings in the card; that means:
4407 o If the SROM has a valid MAC address, and there is no address in the
4408 environment, the SROM's address is used.
4410 o If there is no valid address in the SROM, and a definition in the
4411 environment exists, then the value from the environment variable is
4414 o If both the SROM and the environment contain a MAC address, and
4415 both addresses are the same, this MAC address is used.
4417 o If both the SROM and the environment contain a MAC address, and the
4418 addresses differ, the value from the environment is used and a
4421 o If neither SROM nor the environment contain a MAC address, an error
4424 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4425 will be programmed into hardware as part of the initialization process. This
4426 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4427 The naming convention is as follows:
4428 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4433 U-Boot is capable of booting (and performing other auxiliary operations on)
4434 images in two formats:
4436 New uImage format (FIT)
4437 -----------------------
4439 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4440 to Flattened Device Tree). It allows the use of images with multiple
4441 components (several kernels, ramdisks, etc.), with contents protected by
4442 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4448 Old image format is based on binary files which can be basically anything,
4449 preceded by a special header; see the definitions in include/image.h for
4450 details; basically, the header defines the following image properties:
4452 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4453 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4454 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4455 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4457 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4458 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4459 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4460 * Compression Type (uncompressed, gzip, bzip2)
4466 The header is marked by a special Magic Number, and both the header
4467 and the data portions of the image are secured against corruption by
4474 Although U-Boot should support any OS or standalone application
4475 easily, the main focus has always been on Linux during the design of
4478 U-Boot includes many features that so far have been part of some
4479 special "boot loader" code within the Linux kernel. Also, any
4480 "initrd" images to be used are no longer part of one big Linux image;
4481 instead, kernel and "initrd" are separate images. This implementation
4482 serves several purposes:
4484 - the same features can be used for other OS or standalone
4485 applications (for instance: using compressed images to reduce the
4486 Flash memory footprint)
4488 - it becomes much easier to port new Linux kernel versions because
4489 lots of low-level, hardware dependent stuff are done by U-Boot
4491 - the same Linux kernel image can now be used with different "initrd"
4492 images; of course this also means that different kernel images can
4493 be run with the same "initrd". This makes testing easier (you don't
4494 have to build a new "zImage.initrd" Linux image when you just
4495 change a file in your "initrd"). Also, a field-upgrade of the
4496 software is easier now.
4502 Porting Linux to U-Boot based systems:
4503 ---------------------------------------
4505 U-Boot cannot save you from doing all the necessary modifications to
4506 configure the Linux device drivers for use with your target hardware
4507 (no, we don't intend to provide a full virtual machine interface to
4510 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4512 Just make sure your machine specific header file (for instance
4513 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4514 Information structure as we define in include/asm-<arch>/u-boot.h,
4515 and make sure that your definition of IMAP_ADDR uses the same value
4516 as your U-Boot configuration in CONFIG_SYS_IMMR.
4519 Configuring the Linux kernel:
4520 -----------------------------
4522 No specific requirements for U-Boot. Make sure you have some root
4523 device (initial ramdisk, NFS) for your target system.
4526 Building a Linux Image:
4527 -----------------------
4529 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4530 not used. If you use recent kernel source, a new build target
4531 "uImage" will exist which automatically builds an image usable by
4532 U-Boot. Most older kernels also have support for a "pImage" target,
4533 which was introduced for our predecessor project PPCBoot and uses a
4534 100% compatible format.
4543 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4544 encapsulate a compressed Linux kernel image with header information,
4545 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4547 * build a standard "vmlinux" kernel image (in ELF binary format):
4549 * convert the kernel into a raw binary image:
4551 ${CROSS_COMPILE}-objcopy -O binary \
4552 -R .note -R .comment \
4553 -S vmlinux linux.bin
4555 * compress the binary image:
4559 * package compressed binary image for U-Boot:
4561 mkimage -A ppc -O linux -T kernel -C gzip \
4562 -a 0 -e 0 -n "Linux Kernel Image" \
4563 -d linux.bin.gz uImage
4566 The "mkimage" tool can also be used to create ramdisk images for use
4567 with U-Boot, either separated from the Linux kernel image, or
4568 combined into one file. "mkimage" encapsulates the images with a 64
4569 byte header containing information about target architecture,
4570 operating system, image type, compression method, entry points, time
4571 stamp, CRC32 checksums, etc.
4573 "mkimage" can be called in two ways: to verify existing images and
4574 print the header information, or to build new images.
4576 In the first form (with "-l" option) mkimage lists the information
4577 contained in the header of an existing U-Boot image; this includes
4578 checksum verification:
4580 tools/mkimage -l image
4581 -l ==> list image header information
4583 The second form (with "-d" option) is used to build a U-Boot image
4584 from a "data file" which is used as image payload:
4586 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4587 -n name -d data_file image
4588 -A ==> set architecture to 'arch'
4589 -O ==> set operating system to 'os'
4590 -T ==> set image type to 'type'
4591 -C ==> set compression type 'comp'
4592 -a ==> set load address to 'addr' (hex)
4593 -e ==> set entry point to 'ep' (hex)
4594 -n ==> set image name to 'name'
4595 -d ==> use image data from 'datafile'
4597 Right now, all Linux kernels for PowerPC systems use the same load
4598 address (0x00000000), but the entry point address depends on the
4601 - 2.2.x kernels have the entry point at 0x0000000C,
4602 - 2.3.x and later kernels have the entry point at 0x00000000.
4604 So a typical call to build a U-Boot image would read:
4606 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4607 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4608 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4609 > examples/uImage.TQM850L
4610 Image Name: 2.4.4 kernel for TQM850L
4611 Created: Wed Jul 19 02:34:59 2000
4612 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4613 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4614 Load Address: 0x00000000
4615 Entry Point: 0x00000000
4617 To verify the contents of the image (or check for corruption):
4619 -> tools/mkimage -l examples/uImage.TQM850L
4620 Image Name: 2.4.4 kernel for TQM850L
4621 Created: Wed Jul 19 02:34:59 2000
4622 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4623 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4624 Load Address: 0x00000000
4625 Entry Point: 0x00000000
4627 NOTE: for embedded systems where boot time is critical you can trade
4628 speed for memory and install an UNCOMPRESSED image instead: this
4629 needs more space in Flash, but boots much faster since it does not
4630 need to be uncompressed:
4632 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4633 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4634 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4635 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4636 > examples/uImage.TQM850L-uncompressed
4637 Image Name: 2.4.4 kernel for TQM850L
4638 Created: Wed Jul 19 02:34:59 2000
4639 Image Type: PowerPC Linux Kernel Image (uncompressed)
4640 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4641 Load Address: 0x00000000
4642 Entry Point: 0x00000000
4645 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4646 when your kernel is intended to use an initial ramdisk:
4648 -> tools/mkimage -n 'Simple Ramdisk Image' \
4649 > -A ppc -O linux -T ramdisk -C gzip \
4650 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4651 Image Name: Simple Ramdisk Image
4652 Created: Wed Jan 12 14:01:50 2000
4653 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4654 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4655 Load Address: 0x00000000
4656 Entry Point: 0x00000000
4659 Installing a Linux Image:
4660 -------------------------
4662 To downloading a U-Boot image over the serial (console) interface,
4663 you must convert the image to S-Record format:
4665 objcopy -I binary -O srec examples/image examples/image.srec
4667 The 'objcopy' does not understand the information in the U-Boot
4668 image header, so the resulting S-Record file will be relative to
4669 address 0x00000000. To load it to a given address, you need to
4670 specify the target address as 'offset' parameter with the 'loads'
4673 Example: install the image to address 0x40100000 (which on the
4674 TQM8xxL is in the first Flash bank):
4676 => erase 40100000 401FFFFF
4682 ## Ready for S-Record download ...
4683 ~>examples/image.srec
4684 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4686 15989 15990 15991 15992
4687 [file transfer complete]
4689 ## Start Addr = 0x00000000
4692 You can check the success of the download using the 'iminfo' command;
4693 this includes a checksum verification so you can be sure no data
4694 corruption happened:
4698 ## Checking Image at 40100000 ...
4699 Image Name: 2.2.13 for initrd on TQM850L
4700 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4701 Data Size: 335725 Bytes = 327 kB = 0 MB
4702 Load Address: 00000000
4703 Entry Point: 0000000c
4704 Verifying Checksum ... OK
4710 The "bootm" command is used to boot an application that is stored in
4711 memory (RAM or Flash). In case of a Linux kernel image, the contents
4712 of the "bootargs" environment variable is passed to the kernel as
4713 parameters. You can check and modify this variable using the
4714 "printenv" and "setenv" commands:
4717 => printenv bootargs
4718 bootargs=root=/dev/ram
4720 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4722 => printenv bootargs
4723 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4726 ## Booting Linux kernel at 40020000 ...
4727 Image Name: 2.2.13 for NFS on TQM850L
4728 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4729 Data Size: 381681 Bytes = 372 kB = 0 MB
4730 Load Address: 00000000
4731 Entry Point: 0000000c
4732 Verifying Checksum ... OK
4733 Uncompressing Kernel Image ... OK
4734 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
4735 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4736 time_init: decrementer frequency = 187500000/60
4737 Calibrating delay loop... 49.77 BogoMIPS
4738 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4741 If you want to boot a Linux kernel with initial RAM disk, you pass
4742 the memory addresses of both the kernel and the initrd image (PPBCOOT
4743 format!) to the "bootm" command:
4745 => imi 40100000 40200000
4747 ## Checking Image at 40100000 ...
4748 Image Name: 2.2.13 for initrd on TQM850L
4749 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4750 Data Size: 335725 Bytes = 327 kB = 0 MB
4751 Load Address: 00000000
4752 Entry Point: 0000000c
4753 Verifying Checksum ... OK
4755 ## Checking Image at 40200000 ...
4756 Image Name: Simple Ramdisk Image
4757 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4758 Data Size: 566530 Bytes = 553 kB = 0 MB
4759 Load Address: 00000000
4760 Entry Point: 00000000
4761 Verifying Checksum ... OK
4763 => bootm 40100000 40200000
4764 ## Booting Linux kernel at 40100000 ...
4765 Image Name: 2.2.13 for initrd on TQM850L
4766 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4767 Data Size: 335725 Bytes = 327 kB = 0 MB
4768 Load Address: 00000000
4769 Entry Point: 0000000c
4770 Verifying Checksum ... OK
4771 Uncompressing Kernel Image ... OK
4772 ## Loading RAMDisk Image at 40200000 ...
4773 Image Name: Simple Ramdisk Image
4774 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4775 Data Size: 566530 Bytes = 553 kB = 0 MB
4776 Load Address: 00000000
4777 Entry Point: 00000000
4778 Verifying Checksum ... OK
4779 Loading Ramdisk ... OK
4780 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
4781 Boot arguments: root=/dev/ram
4782 time_init: decrementer frequency = 187500000/60
4783 Calibrating delay loop... 49.77 BogoMIPS
4785 RAMDISK: Compressed image found at block 0
4786 VFS: Mounted root (ext2 filesystem).
4790 Boot Linux and pass a flat device tree:
4793 First, U-Boot must be compiled with the appropriate defines. See the section
4794 titled "Linux Kernel Interface" above for a more in depth explanation. The
4795 following is an example of how to start a kernel and pass an updated
4801 oft=oftrees/mpc8540ads.dtb
4802 => tftp $oftaddr $oft
4803 Speed: 1000, full duplex
4805 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4806 Filename 'oftrees/mpc8540ads.dtb'.
4807 Load address: 0x300000
4810 Bytes transferred = 4106 (100a hex)
4811 => tftp $loadaddr $bootfile
4812 Speed: 1000, full duplex
4814 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4816 Load address: 0x200000
4817 Loading:############
4819 Bytes transferred = 1029407 (fb51f hex)
4824 => bootm $loadaddr - $oftaddr
4825 ## Booting image at 00200000 ...
4826 Image Name: Linux-2.6.17-dirty
4827 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4828 Data Size: 1029343 Bytes = 1005.2 kB
4829 Load Address: 00000000
4830 Entry Point: 00000000
4831 Verifying Checksum ... OK
4832 Uncompressing Kernel Image ... OK
4833 Booting using flat device tree at 0x300000
4834 Using MPC85xx ADS machine description
4835 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4839 More About U-Boot Image Types:
4840 ------------------------------
4842 U-Boot supports the following image types:
4844 "Standalone Programs" are directly runnable in the environment
4845 provided by U-Boot; it is expected that (if they behave
4846 well) you can continue to work in U-Boot after return from
4847 the Standalone Program.
4848 "OS Kernel Images" are usually images of some Embedded OS which
4849 will take over control completely. Usually these programs
4850 will install their own set of exception handlers, device
4851 drivers, set up the MMU, etc. - this means, that you cannot
4852 expect to re-enter U-Boot except by resetting the CPU.
4853 "RAMDisk Images" are more or less just data blocks, and their
4854 parameters (address, size) are passed to an OS kernel that is
4856 "Multi-File Images" contain several images, typically an OS
4857 (Linux) kernel image and one or more data images like
4858 RAMDisks. This construct is useful for instance when you want
4859 to boot over the network using BOOTP etc., where the boot
4860 server provides just a single image file, but you want to get
4861 for instance an OS kernel and a RAMDisk image.
4863 "Multi-File Images" start with a list of image sizes, each
4864 image size (in bytes) specified by an "uint32_t" in network
4865 byte order. This list is terminated by an "(uint32_t)0".
4866 Immediately after the terminating 0 follow the images, one by
4867 one, all aligned on "uint32_t" boundaries (size rounded up to
4868 a multiple of 4 bytes).
4870 "Firmware Images" are binary images containing firmware (like
4871 U-Boot or FPGA images) which usually will be programmed to
4874 "Script files" are command sequences that will be executed by
4875 U-Boot's command interpreter; this feature is especially
4876 useful when you configure U-Boot to use a real shell (hush)
4877 as command interpreter.
4879 Booting the Linux zImage:
4880 -------------------------
4882 On some platforms, it's possible to boot Linux zImage. This is done
4883 using the "bootz" command. The syntax of "bootz" command is the same
4884 as the syntax of "bootm" command.
4886 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4887 kernel with raw initrd images. The syntax is slightly different, the
4888 address of the initrd must be augmented by it's size, in the following
4889 format: "<initrd addres>:<initrd size>".
4895 One of the features of U-Boot is that you can dynamically load and
4896 run "standalone" applications, which can use some resources of
4897 U-Boot like console I/O functions or interrupt services.
4899 Two simple examples are included with the sources:
4904 'examples/hello_world.c' contains a small "Hello World" Demo
4905 application; it is automatically compiled when you build U-Boot.
4906 It's configured to run at address 0x00040004, so you can play with it
4910 ## Ready for S-Record download ...
4911 ~>examples/hello_world.srec
4912 1 2 3 4 5 6 7 8 9 10 11 ...
4913 [file transfer complete]
4915 ## Start Addr = 0x00040004
4917 => go 40004 Hello World! This is a test.
4918 ## Starting application at 0x00040004 ...
4929 Hit any key to exit ...
4931 ## Application terminated, rc = 0x0
4933 Another example, which demonstrates how to register a CPM interrupt
4934 handler with the U-Boot code, can be found in 'examples/timer.c'.
4935 Here, a CPM timer is set up to generate an interrupt every second.
4936 The interrupt service routine is trivial, just printing a '.'
4937 character, but this is just a demo program. The application can be
4938 controlled by the following keys:
4940 ? - print current values og the CPM Timer registers
4941 b - enable interrupts and start timer
4942 e - stop timer and disable interrupts
4943 q - quit application
4946 ## Ready for S-Record download ...
4947 ~>examples/timer.srec
4948 1 2 3 4 5 6 7 8 9 10 11 ...
4949 [file transfer complete]
4951 ## Start Addr = 0x00040004
4954 ## Starting application at 0x00040004 ...
4957 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4960 [q, b, e, ?] Set interval 1000000 us
4963 [q, b, e, ?] ........
4964 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4967 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4970 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4973 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4975 [q, b, e, ?] ...Stopping timer
4977 [q, b, e, ?] ## Application terminated, rc = 0x0
4983 Over time, many people have reported problems when trying to use the
4984 "minicom" terminal emulation program for serial download. I (wd)
4985 consider minicom to be broken, and recommend not to use it. Under
4986 Unix, I recommend to use C-Kermit for general purpose use (and
4987 especially for kermit binary protocol download ("loadb" command), and
4988 use "cu" for S-Record download ("loads" command). See
4989 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4990 for help with kermit.
4993 Nevertheless, if you absolutely want to use it try adding this
4994 configuration to your "File transfer protocols" section:
4996 Name Program Name U/D FullScr IO-Red. Multi
4997 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4998 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5004 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5005 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5007 Building requires a cross environment; it is known to work on
5008 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5009 need gmake since the Makefiles are not compatible with BSD make).
5010 Note that the cross-powerpc package does not install include files;
5011 attempting to build U-Boot will fail because <machine/ansi.h> is
5012 missing. This file has to be installed and patched manually:
5014 # cd /usr/pkg/cross/powerpc-netbsd/include
5016 # ln -s powerpc machine
5017 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5018 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5020 Native builds *don't* work due to incompatibilities between native
5021 and U-Boot include files.
5023 Booting assumes that (the first part of) the image booted is a
5024 stage-2 loader which in turn loads and then invokes the kernel
5025 proper. Loader sources will eventually appear in the NetBSD source
5026 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5027 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5030 Implementation Internals:
5031 =========================
5033 The following is not intended to be a complete description of every
5034 implementation detail. However, it should help to understand the
5035 inner workings of U-Boot and make it easier to port it to custom
5039 Initial Stack, Global Data:
5040 ---------------------------
5042 The implementation of U-Boot is complicated by the fact that U-Boot
5043 starts running out of ROM (flash memory), usually without access to
5044 system RAM (because the memory controller is not initialized yet).
5045 This means that we don't have writable Data or BSS segments, and BSS
5046 is not initialized as zero. To be able to get a C environment working
5047 at all, we have to allocate at least a minimal stack. Implementation
5048 options for this are defined and restricted by the CPU used: Some CPU
5049 models provide on-chip memory (like the IMMR area on MPC8xx and
5050 MPC826x processors), on others (parts of) the data cache can be
5051 locked as (mis-) used as memory, etc.
5053 Chris Hallinan posted a good summary of these issues to the
5054 U-Boot mailing list:
5056 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5057 From: "Chris Hallinan" <clh@net1plus.com>
5058 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5061 Correct me if I'm wrong, folks, but the way I understand it
5062 is this: Using DCACHE as initial RAM for Stack, etc, does not
5063 require any physical RAM backing up the cache. The cleverness
5064 is that the cache is being used as a temporary supply of
5065 necessary storage before the SDRAM controller is setup. It's
5066 beyond the scope of this list to explain the details, but you
5067 can see how this works by studying the cache architecture and
5068 operation in the architecture and processor-specific manuals.
5070 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5071 is another option for the system designer to use as an
5072 initial stack/RAM area prior to SDRAM being available. Either
5073 option should work for you. Using CS 4 should be fine if your
5074 board designers haven't used it for something that would
5075 cause you grief during the initial boot! It is frequently not
5078 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5079 with your processor/board/system design. The default value
5080 you will find in any recent u-boot distribution in
5081 walnut.h should work for you. I'd set it to a value larger
5082 than your SDRAM module. If you have a 64MB SDRAM module, set
5083 it above 400_0000. Just make sure your board has no resources
5084 that are supposed to respond to that address! That code in
5085 start.S has been around a while and should work as is when
5086 you get the config right.
5091 It is essential to remember this, since it has some impact on the C
5092 code for the initialization procedures:
5094 * Initialized global data (data segment) is read-only. Do not attempt
5097 * Do not use any uninitialized global data (or implicitely initialized
5098 as zero data - BSS segment) at all - this is undefined, initiali-
5099 zation is performed later (when relocating to RAM).
5101 * Stack space is very limited. Avoid big data buffers or things like
5104 Having only the stack as writable memory limits means we cannot use
5105 normal global data to share information beween the code. But it
5106 turned out that the implementation of U-Boot can be greatly
5107 simplified by making a global data structure (gd_t) available to all
5108 functions. We could pass a pointer to this data as argument to _all_
5109 functions, but this would bloat the code. Instead we use a feature of
5110 the GCC compiler (Global Register Variables) to share the data: we
5111 place a pointer (gd) to the global data into a register which we
5112 reserve for this purpose.
5114 When choosing a register for such a purpose we are restricted by the
5115 relevant (E)ABI specifications for the current architecture, and by
5116 GCC's implementation.
5118 For PowerPC, the following registers have specific use:
5120 R2: reserved for system use
5121 R3-R4: parameter passing and return values
5122 R5-R10: parameter passing
5123 R13: small data area pointer
5127 (U-Boot also uses R12 as internal GOT pointer. r12
5128 is a volatile register so r12 needs to be reset when
5129 going back and forth between asm and C)
5131 ==> U-Boot will use R2 to hold a pointer to the global data
5133 Note: on PPC, we could use a static initializer (since the
5134 address of the global data structure is known at compile time),
5135 but it turned out that reserving a register results in somewhat
5136 smaller code - although the code savings are not that big (on
5137 average for all boards 752 bytes for the whole U-Boot image,
5138 624 text + 127 data).
5140 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5141 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5143 ==> U-Boot will use P3 to hold a pointer to the global data
5145 On ARM, the following registers are used:
5147 R0: function argument word/integer result
5148 R1-R3: function argument word
5150 R10: stack limit (used only if stack checking if enabled)
5151 R11: argument (frame) pointer
5152 R12: temporary workspace
5155 R15: program counter
5157 ==> U-Boot will use R8 to hold a pointer to the global data
5159 On Nios II, the ABI is documented here:
5160 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5162 ==> U-Boot will use gp to hold a pointer to the global data
5164 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5165 to access small data sections, so gp is free.
5167 On NDS32, the following registers are used:
5169 R0-R1: argument/return
5171 R15: temporary register for assembler
5172 R16: trampoline register
5173 R28: frame pointer (FP)
5174 R29: global pointer (GP)
5175 R30: link register (LP)
5176 R31: stack pointer (SP)
5177 PC: program counter (PC)
5179 ==> U-Boot will use R10 to hold a pointer to the global data
5181 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5182 or current versions of GCC may "optimize" the code too much.
5187 U-Boot runs in system state and uses physical addresses, i.e. the
5188 MMU is not used either for address mapping nor for memory protection.
5190 The available memory is mapped to fixed addresses using the memory
5191 controller. In this process, a contiguous block is formed for each
5192 memory type (Flash, SDRAM, SRAM), even when it consists of several
5193 physical memory banks.
5195 U-Boot is installed in the first 128 kB of the first Flash bank (on
5196 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5197 booting and sizing and initializing DRAM, the code relocates itself
5198 to the upper end of DRAM. Immediately below the U-Boot code some
5199 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5200 configuration setting]. Below that, a structure with global Board
5201 Info data is placed, followed by the stack (growing downward).
5203 Additionally, some exception handler code is copied to the low 8 kB
5204 of DRAM (0x00000000 ... 0x00001FFF).
5206 So a typical memory configuration with 16 MB of DRAM could look like
5209 0x0000 0000 Exception Vector code
5212 0x0000 2000 Free for Application Use
5218 0x00FB FF20 Monitor Stack (Growing downward)
5219 0x00FB FFAC Board Info Data and permanent copy of global data
5220 0x00FC 0000 Malloc Arena
5223 0x00FE 0000 RAM Copy of Monitor Code
5224 ... eventually: LCD or video framebuffer
5225 ... eventually: pRAM (Protected RAM - unchanged by reset)
5226 0x00FF FFFF [End of RAM]
5229 System Initialization:
5230 ----------------------
5232 In the reset configuration, U-Boot starts at the reset entry point
5233 (on most PowerPC systems at address 0x00000100). Because of the reset
5234 configuration for CS0# this is a mirror of the onboard Flash memory.
5235 To be able to re-map memory U-Boot then jumps to its link address.
5236 To be able to implement the initialization code in C, a (small!)
5237 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5238 which provide such a feature like MPC8xx or MPC8260), or in a locked
5239 part of the data cache. After that, U-Boot initializes the CPU core,
5240 the caches and the SIU.
5242 Next, all (potentially) available memory banks are mapped using a
5243 preliminary mapping. For example, we put them on 512 MB boundaries
5244 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5245 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5246 programmed for SDRAM access. Using the temporary configuration, a
5247 simple memory test is run that determines the size of the SDRAM
5250 When there is more than one SDRAM bank, and the banks are of
5251 different size, the largest is mapped first. For equal size, the first
5252 bank (CS2#) is mapped first. The first mapping is always for address
5253 0x00000000, with any additional banks following immediately to create
5254 contiguous memory starting from 0.
5256 Then, the monitor installs itself at the upper end of the SDRAM area
5257 and allocates memory for use by malloc() and for the global Board
5258 Info data; also, the exception vector code is copied to the low RAM
5259 pages, and the final stack is set up.
5261 Only after this relocation will you have a "normal" C environment;
5262 until that you are restricted in several ways, mostly because you are
5263 running from ROM, and because the code will have to be relocated to a
5267 U-Boot Porting Guide:
5268 ----------------------
5270 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5274 int main(int argc, char *argv[])
5276 sighandler_t no_more_time;
5278 signal(SIGALRM, no_more_time);
5279 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5281 if (available_money > available_manpower) {
5282 Pay consultant to port U-Boot;
5286 Download latest U-Boot source;
5288 Subscribe to u-boot mailing list;
5291 email("Hi, I am new to U-Boot, how do I get started?");
5294 Read the README file in the top level directory;
5295 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5296 Read applicable doc/*.README;
5297 Read the source, Luke;
5298 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5301 if (available_money > toLocalCurrency ($2500))
5304 Add a lot of aggravation and time;
5306 if (a similar board exists) { /* hopefully... */
5307 cp -a board/<similar> board/<myboard>
5308 cp include/configs/<similar>.h include/configs/<myboard>.h
5310 Create your own board support subdirectory;
5311 Create your own board include/configs/<myboard>.h file;
5313 Edit new board/<myboard> files
5314 Edit new include/configs/<myboard>.h
5319 Add / modify source code;
5323 email("Hi, I am having problems...");
5325 Send patch file to the U-Boot email list;
5326 if (reasonable critiques)
5327 Incorporate improvements from email list code review;
5329 Defend code as written;
5335 void no_more_time (int sig)
5344 All contributions to U-Boot should conform to the Linux kernel
5345 coding style; see the file "Documentation/CodingStyle" and the script
5346 "scripts/Lindent" in your Linux kernel source directory.
5348 Source files originating from a different project (for example the
5349 MTD subsystem) are generally exempt from these guidelines and are not
5350 reformated to ease subsequent migration to newer versions of those
5353 Please note that U-Boot is implemented in C (and to some small parts in
5354 Assembler); no C++ is used, so please do not use C++ style comments (//)
5357 Please also stick to the following formatting rules:
5358 - remove any trailing white space
5359 - use TAB characters for indentation and vertical alignment, not spaces
5360 - make sure NOT to use DOS '\r\n' line feeds
5361 - do not add more than 2 consecutive empty lines to source files
5362 - do not add trailing empty lines to source files
5364 Submissions which do not conform to the standards may be returned
5365 with a request to reformat the changes.
5371 Since the number of patches for U-Boot is growing, we need to
5372 establish some rules. Submissions which do not conform to these rules
5373 may be rejected, even when they contain important and valuable stuff.
5375 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5377 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5378 see http://lists.denx.de/mailman/listinfo/u-boot
5380 When you send a patch, please include the following information with
5383 * For bug fixes: a description of the bug and how your patch fixes
5384 this bug. Please try to include a way of demonstrating that the
5385 patch actually fixes something.
5387 * For new features: a description of the feature and your
5390 * A CHANGELOG entry as plaintext (separate from the patch)
5392 * For major contributions, your entry to the CREDITS file
5394 * When you add support for a new board, don't forget to add this
5395 board to the MAINTAINERS file, too.
5397 * If your patch adds new configuration options, don't forget to
5398 document these in the README file.
5400 * The patch itself. If you are using git (which is *strongly*
5401 recommended) you can easily generate the patch using the
5402 "git format-patch". If you then use "git send-email" to send it to
5403 the U-Boot mailing list, you will avoid most of the common problems
5404 with some other mail clients.
5406 If you cannot use git, use "diff -purN OLD NEW". If your version of
5407 diff does not support these options, then get the latest version of
5410 The current directory when running this command shall be the parent
5411 directory of the U-Boot source tree (i. e. please make sure that
5412 your patch includes sufficient directory information for the
5415 We prefer patches as plain text. MIME attachments are discouraged,
5416 and compressed attachments must not be used.
5418 * If one logical set of modifications affects or creates several
5419 files, all these changes shall be submitted in a SINGLE patch file.
5421 * Changesets that contain different, unrelated modifications shall be
5422 submitted as SEPARATE patches, one patch per changeset.
5427 * Before sending the patch, run the MAKEALL script on your patched
5428 source tree and make sure that no errors or warnings are reported
5429 for any of the boards.
5431 * Keep your modifications to the necessary minimum: A patch
5432 containing several unrelated changes or arbitrary reformats will be
5433 returned with a request to re-formatting / split it.
5435 * If you modify existing code, make sure that your new code does not
5436 add to the memory footprint of the code ;-) Small is beautiful!
5437 When adding new features, these should compile conditionally only
5438 (using #ifdef), and the resulting code with the new feature
5439 disabled must not need more memory than the old code without your
5442 * Remember that there is a size limit of 100 kB per message on the
5443 u-boot mailing list. Bigger patches will be moderated. If they are
5444 reasonable and not too big, they will be acknowledged. But patches
5445 bigger than the size limit should be avoided.
projects / kernel / u-boot.git / blob