2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 - Linux Kernel Interface:
491 U-Boot stores all clock information in Hz
492 internally. For binary compatibility with older Linux
493 kernels (which expect the clocks passed in the
494 bd_info data to be in MHz) the environment variable
495 "clocks_in_mhz" can be defined so that U-Boot
496 converts clock data to MHZ before passing it to the
498 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
499 "clocks_in_mhz=1" is automatically included in the
502 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
504 When transferring memsize parameter to linux, some versions
505 expect it to be in bytes, others in MB.
506 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
510 New kernel versions are expecting firmware settings to be
511 passed using flattened device trees (based on open firmware
515 * New libfdt-based support
516 * Adds the "fdt" command
517 * The bootm command automatically updates the fdt
519 OF_CPU - The proper name of the cpus node (only required for
520 MPC512X and MPC5xxx based boards).
521 OF_SOC - The proper name of the soc node (only required for
522 MPC512X and MPC5xxx based boards).
523 OF_TBCLK - The timebase frequency.
524 OF_STDOUT_PATH - The path to the console device
526 boards with QUICC Engines require OF_QE to set UCC MAC
529 CONFIG_OF_BOARD_SETUP
531 Board code has addition modification that it wants to make
532 to the flat device tree before handing it off to the kernel
536 This define fills in the correct boot CPU in the boot
537 param header, the default value is zero if undefined.
541 U-Boot can detect if an IDE device is present or not.
542 If not, and this new config option is activated, U-Boot
543 removes the ATA node from the DTS before booting Linux,
544 so the Linux IDE driver does not probe the device and
545 crash. This is needed for buggy hardware (uc101) where
546 no pull down resistor is connected to the signal IDE5V_DD7.
548 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
550 This setting is mandatory for all boards that have only one
551 machine type and must be used to specify the machine type
552 number as it appears in the ARM machine registry
553 (see http://www.arm.linux.org.uk/developer/machines/).
554 Only boards that have multiple machine types supported
555 in a single configuration file and the machine type is
556 runtime discoverable, do not have to use this setting.
558 - vxWorks boot parameters:
560 bootvx constructs a valid bootline using the following
561 environments variables: bootfile, ipaddr, serverip, hostname.
562 It loads the vxWorks image pointed bootfile.
564 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
565 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
566 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
567 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
569 CONFIG_SYS_VXWORKS_ADD_PARAMS
571 Add it at the end of the bootline. E.g "u=username pw=secret"
573 Note: If a "bootargs" environment is defined, it will overwride
574 the defaults discussed just above.
576 - Cache Configuration:
577 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
578 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
579 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
581 - Cache Configuration for ARM:
582 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
584 CONFIG_SYS_PL310_BASE - Physical base address of PL310
585 controller register space
590 Define this if you want support for Amba PrimeCell PL010 UARTs.
594 Define this if you want support for Amba PrimeCell PL011 UARTs.
598 If you have Amba PrimeCell PL011 UARTs, set this variable to
599 the clock speed of the UARTs.
603 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
604 define this to a list of base addresses for each (supported)
605 port. See e.g. include/configs/versatile.h
607 CONFIG_PL011_SERIAL_RLCR
609 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
610 have separate receive and transmit line control registers. Set
611 this variable to initialize the extra register.
613 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
615 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
616 boot loader that has already initialized the UART. Define this
617 variable to flush the UART at init time.
621 Depending on board, define exactly one serial port
622 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
623 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
624 console by defining CONFIG_8xx_CONS_NONE
626 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
627 port routines must be defined elsewhere
628 (i.e. serial_init(), serial_getc(), ...)
631 Enables console device for a color framebuffer. Needs following
632 defines (cf. smiLynxEM, i8042)
633 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
635 VIDEO_HW_RECTFILL graphic chip supports
638 VIDEO_HW_BITBLT graphic chip supports
639 bit-blit (cf. smiLynxEM)
640 VIDEO_VISIBLE_COLS visible pixel columns
642 VIDEO_VISIBLE_ROWS visible pixel rows
643 VIDEO_PIXEL_SIZE bytes per pixel
644 VIDEO_DATA_FORMAT graphic data format
645 (0-5, cf. cfb_console.c)
646 VIDEO_FB_ADRS framebuffer address
647 VIDEO_KBD_INIT_FCT keyboard int fct
648 (i.e. i8042_kbd_init())
649 VIDEO_TSTC_FCT test char fct
651 VIDEO_GETC_FCT get char fct
653 CONFIG_CONSOLE_CURSOR cursor drawing on/off
654 (requires blink timer
656 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
657 CONFIG_CONSOLE_TIME display time/date info in
659 (requires CONFIG_CMD_DATE)
660 CONFIG_VIDEO_LOGO display Linux logo in
662 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
663 linux_logo.h for logo.
664 Requires CONFIG_VIDEO_LOGO
665 CONFIG_CONSOLE_EXTRA_INFO
666 additional board info beside
669 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
670 a limited number of ANSI escape sequences (cursor control,
671 erase functions and limited graphics rendition control).
673 When CONFIG_CFB_CONSOLE is defined, video console is
674 default i/o. Serial console can be forced with
675 environment 'console=serial'.
677 When CONFIG_SILENT_CONSOLE is defined, all console
678 messages (by U-Boot and Linux!) can be silenced with
679 the "silent" environment variable. See
680 doc/README.silent for more information.
683 CONFIG_BAUDRATE - in bps
684 Select one of the baudrates listed in
685 CONFIG_SYS_BAUDRATE_TABLE, see below.
686 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
688 - Console Rx buffer length
689 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
690 the maximum receive buffer length for the SMC.
691 This option is actual only for 82xx and 8xx possible.
692 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
693 must be defined, to setup the maximum idle timeout for
696 - Pre-Console Buffer:
697 Prior to the console being initialised (i.e. serial UART
698 initialised etc) all console output is silently discarded.
699 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
700 buffer any console messages prior to the console being
701 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
702 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
703 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
704 bytes are output before the console is initialised, the
705 earlier bytes are discarded.
707 'Sane' compilers will generate smaller code if
708 CONFIG_PRE_CON_BUF_SZ is a power of 2
710 - Safe printf() functions
711 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
712 the printf() functions. These are defined in
713 include/vsprintf.h and include snprintf(), vsnprintf() and
714 so on. Code size increase is approximately 300-500 bytes.
715 If this option is not given then these functions will
716 silently discard their buffer size argument - this means
717 you are not getting any overflow checking in this case.
719 - Boot Delay: CONFIG_BOOTDELAY - in seconds
720 Delay before automatically booting the default image;
721 set to -1 to disable autoboot.
722 set to -2 to autoboot with no delay and not check for abort
723 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
725 See doc/README.autoboot for these options that
726 work with CONFIG_BOOTDELAY. None are required.
727 CONFIG_BOOT_RETRY_TIME
728 CONFIG_BOOT_RETRY_MIN
729 CONFIG_AUTOBOOT_KEYED
730 CONFIG_AUTOBOOT_PROMPT
731 CONFIG_AUTOBOOT_DELAY_STR
732 CONFIG_AUTOBOOT_STOP_STR
733 CONFIG_AUTOBOOT_DELAY_STR2
734 CONFIG_AUTOBOOT_STOP_STR2
735 CONFIG_ZERO_BOOTDELAY_CHECK
736 CONFIG_RESET_TO_RETRY
740 Only needed when CONFIG_BOOTDELAY is enabled;
741 define a command string that is automatically executed
742 when no character is read on the console interface
743 within "Boot Delay" after reset.
746 This can be used to pass arguments to the bootm
747 command. The value of CONFIG_BOOTARGS goes into the
748 environment value "bootargs".
750 CONFIG_RAMBOOT and CONFIG_NFSBOOT
751 The value of these goes into the environment as
752 "ramboot" and "nfsboot" respectively, and can be used
753 as a convenience, when switching between booting from
759 When this option is #defined, the existence of the
760 environment variable "preboot" will be checked
761 immediately before starting the CONFIG_BOOTDELAY
762 countdown and/or running the auto-boot command resp.
763 entering interactive mode.
765 This feature is especially useful when "preboot" is
766 automatically generated or modified. For an example
767 see the LWMON board specific code: here "preboot" is
768 modified when the user holds down a certain
769 combination of keys on the (special) keyboard when
772 - Serial Download Echo Mode:
774 If defined to 1, all characters received during a
775 serial download (using the "loads" command) are
776 echoed back. This might be needed by some terminal
777 emulations (like "cu"), but may as well just take
778 time on others. This setting #define's the initial
779 value of the "loads_echo" environment variable.
781 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
783 Select one of the baudrates listed in
784 CONFIG_SYS_BAUDRATE_TABLE, see below.
787 Monitor commands can be included or excluded
788 from the build by using the #include files
789 <config_cmd_all.h> and #undef'ing unwanted
790 commands, or using <config_cmd_default.h>
791 and augmenting with additional #define's
794 The default command configuration includes all commands
795 except those marked below with a "*".
797 CONFIG_CMD_ASKENV * ask for env variable
798 CONFIG_CMD_BDI bdinfo
799 CONFIG_CMD_BEDBUG * Include BedBug Debugger
800 CONFIG_CMD_BMP * BMP support
801 CONFIG_CMD_BSP * Board specific commands
802 CONFIG_CMD_BOOTD bootd
803 CONFIG_CMD_CACHE * icache, dcache
804 CONFIG_CMD_CONSOLE coninfo
805 CONFIG_CMD_CRC32 * crc32
806 CONFIG_CMD_DATE * support for RTC, date/time...
807 CONFIG_CMD_DHCP * DHCP support
808 CONFIG_CMD_DIAG * Diagnostics
809 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
810 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
811 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
812 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
813 CONFIG_CMD_DTT * Digital Therm and Thermostat
814 CONFIG_CMD_ECHO echo arguments
815 CONFIG_CMD_EDITENV edit env variable
816 CONFIG_CMD_EEPROM * EEPROM read/write support
817 CONFIG_CMD_ELF * bootelf, bootvx
818 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
819 CONFIG_CMD_ENV_FLAGS * display details about env flags
820 CONFIG_CMD_EXPORTENV * export the environment
821 CONFIG_CMD_EXT2 * ext2 command support
822 CONFIG_CMD_EXT4 * ext4 command support
823 CONFIG_CMD_SAVEENV saveenv
824 CONFIG_CMD_FDC * Floppy Disk Support
825 CONFIG_CMD_FAT * FAT command support
826 CONFIG_CMD_FDOS * Dos diskette Support
827 CONFIG_CMD_FLASH flinfo, erase, protect
828 CONFIG_CMD_FPGA FPGA device initialization support
829 CONFIG_CMD_GETTIME * Get time since boot
830 CONFIG_CMD_GO * the 'go' command (exec code)
831 CONFIG_CMD_GREPENV * search environment
832 CONFIG_CMD_HASH * calculate hash / digest
833 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
834 CONFIG_CMD_I2C * I2C serial bus support
835 CONFIG_CMD_IDE * IDE harddisk support
836 CONFIG_CMD_IMI iminfo
837 CONFIG_CMD_IMLS List all found images
838 CONFIG_CMD_IMMAP * IMMR dump support
839 CONFIG_CMD_IMPORTENV * import an environment
840 CONFIG_CMD_INI * import data from an ini file into the env
841 CONFIG_CMD_IRQ * irqinfo
842 CONFIG_CMD_ITEST Integer/string test of 2 values
843 CONFIG_CMD_JFFS2 * JFFS2 Support
844 CONFIG_CMD_KGDB * kgdb
845 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
846 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
848 CONFIG_CMD_LOADB loadb
849 CONFIG_CMD_LOADS loads
850 CONFIG_CMD_MD5SUM print md5 message digest
851 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
852 CONFIG_CMD_MEMINFO * Display detailed memory information
853 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
855 CONFIG_CMD_MISC Misc functions like sleep etc
856 CONFIG_CMD_MMC * MMC memory mapped support
857 CONFIG_CMD_MII * MII utility commands
858 CONFIG_CMD_MTDPARTS * MTD partition support
859 CONFIG_CMD_NAND * NAND support
860 CONFIG_CMD_NET bootp, tftpboot, rarpboot
861 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
862 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
863 CONFIG_CMD_PCI * pciinfo
864 CONFIG_CMD_PCMCIA * PCMCIA support
865 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
867 CONFIG_CMD_PORTIO * Port I/O
868 CONFIG_CMD_READ * Read raw data from partition
869 CONFIG_CMD_REGINFO * Register dump
870 CONFIG_CMD_RUN run command in env variable
871 CONFIG_CMD_SAVES * save S record dump
872 CONFIG_CMD_SCSI * SCSI Support
873 CONFIG_CMD_SDRAM * print SDRAM configuration information
874 (requires CONFIG_CMD_I2C)
875 CONFIG_CMD_SETGETDCR Support for DCR Register access
877 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
878 CONFIG_CMD_SHA1SUM print sha1 memory digest
879 (requires CONFIG_CMD_MEMORY)
880 CONFIG_CMD_SOURCE "source" command Support
881 CONFIG_CMD_SPI * SPI serial bus support
882 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
883 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
884 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
885 CONFIG_CMD_TIMER * access to the system tick timer
886 CONFIG_CMD_USB * USB support
887 CONFIG_CMD_CDP * Cisco Discover Protocol support
888 CONFIG_CMD_MFSL * Microblaze FSL support
891 EXAMPLE: If you want all functions except of network
892 support you can write:
894 #include "config_cmd_all.h"
895 #undef CONFIG_CMD_NET
898 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
900 Note: Don't enable the "icache" and "dcache" commands
901 (configuration option CONFIG_CMD_CACHE) unless you know
902 what you (and your U-Boot users) are doing. Data
903 cache cannot be enabled on systems like the 8xx or
904 8260 (where accesses to the IMMR region must be
905 uncached), and it cannot be disabled on all other
906 systems where we (mis-) use the data cache to hold an
907 initial stack and some data.
910 XXX - this list needs to get updated!
914 If this variable is defined, U-Boot will use a device tree
915 to configure its devices, instead of relying on statically
916 compiled #defines in the board file. This option is
917 experimental and only available on a few boards. The device
918 tree is available in the global data as gd->fdt_blob.
920 U-Boot needs to get its device tree from somewhere. This can
921 be done using one of the two options below:
924 If this variable is defined, U-Boot will embed a device tree
925 binary in its image. This device tree file should be in the
926 board directory and called <soc>-<board>.dts. The binary file
927 is then picked up in board_init_f() and made available through
928 the global data structure as gd->blob.
931 If this variable is defined, U-Boot will build a device tree
932 binary. It will be called u-boot.dtb. Architecture-specific
933 code will locate it at run-time. Generally this works by:
935 cat u-boot.bin u-boot.dtb >image.bin
937 and in fact, U-Boot does this for you, creating a file called
938 u-boot-dtb.bin which is useful in the common case. You can
939 still use the individual files if you need something more
944 If this variable is defined, it enables watchdog
945 support for the SoC. There must be support in the SoC
946 specific code for a watchdog. For the 8xx and 8260
947 CPUs, the SIU Watchdog feature is enabled in the SYPCR
948 register. When supported for a specific SoC is
949 available, then no further board specific code should
953 When using a watchdog circuitry external to the used
954 SoC, then define this variable and provide board
955 specific code for the "hw_watchdog_reset" function.
958 CONFIG_VERSION_VARIABLE
959 If this variable is defined, an environment variable
960 named "ver" is created by U-Boot showing the U-Boot
961 version as printed by the "version" command.
962 Any change to this variable will be reverted at the
967 When CONFIG_CMD_DATE is selected, the type of the RTC
968 has to be selected, too. Define exactly one of the
971 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
972 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
973 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
974 CONFIG_RTC_MC146818 - use MC146818 RTC
975 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
976 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
977 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
978 CONFIG_RTC_DS164x - use Dallas DS164x RTC
979 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
980 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
981 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
982 CONFIG_SYS_RV3029_TCR - enable trickle charger on
985 Note that if the RTC uses I2C, then the I2C interface
986 must also be configured. See I2C Support, below.
989 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
990 CONFIG_PCA953X_INFO - enable pca953x info command
992 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
993 chip-ngpio pairs that tell the PCA953X driver the number of
994 pins supported by a particular chip.
996 Note that if the GPIO device uses I2C, then the I2C interface
997 must also be configured. See I2C Support, below.
1001 When CONFIG_TIMESTAMP is selected, the timestamp
1002 (date and time) of an image is printed by image
1003 commands like bootm or iminfo. This option is
1004 automatically enabled when you select CONFIG_CMD_DATE .
1006 - Partition Labels (disklabels) Supported:
1007 Zero or more of the following:
1008 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1009 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1010 Intel architecture, USB sticks, etc.
1011 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1012 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1013 bootloader. Note 2TB partition limit; see
1015 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1017 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1018 CONFIG_CMD_SCSI) you must configure support for at
1019 least one non-MTD partition type as well.
1022 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1023 board configurations files but used nowhere!
1025 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1026 be performed by calling the function
1027 ide_set_reset(int reset)
1028 which has to be defined in a board specific file
1033 Set this to enable ATAPI support.
1038 Set this to enable support for disks larger than 137GB
1039 Also look at CONFIG_SYS_64BIT_LBA.
1040 Whithout these , LBA48 support uses 32bit variables and will 'only'
1041 support disks up to 2.1TB.
1043 CONFIG_SYS_64BIT_LBA:
1044 When enabled, makes the IDE subsystem use 64bit sector addresses.
1048 At the moment only there is only support for the
1049 SYM53C8XX SCSI controller; define
1050 CONFIG_SCSI_SYM53C8XX to enable it.
1052 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1053 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1054 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1055 maximum numbers of LUNs, SCSI ID's and target
1057 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1059 The environment variable 'scsidevs' is set to the number of
1060 SCSI devices found during the last scan.
1062 - NETWORK Support (PCI):
1064 Support for Intel 8254x/8257x gigabit chips.
1067 Utility code for direct access to the SPI bus on Intel 8257x.
1068 This does not do anything useful unless you set at least one
1069 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1071 CONFIG_E1000_SPI_GENERIC
1072 Allow generic access to the SPI bus on the Intel 8257x, for
1073 example with the "sspi" command.
1076 Management command for E1000 devices. When used on devices
1077 with SPI support you can reprogram the EEPROM from U-Boot.
1079 CONFIG_E1000_FALLBACK_MAC
1080 default MAC for empty EEPROM after production.
1083 Support for Intel 82557/82559/82559ER chips.
1084 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1085 write routine for first time initialisation.
1088 Support for Digital 2114x chips.
1089 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1090 modem chip initialisation (KS8761/QS6611).
1093 Support for National dp83815 chips.
1096 Support for National dp8382[01] gigabit chips.
1098 - NETWORK Support (other):
1100 CONFIG_DRIVER_AT91EMAC
1101 Support for AT91RM9200 EMAC.
1104 Define this to use reduced MII inteface
1106 CONFIG_DRIVER_AT91EMAC_QUIET
1107 If this defined, the driver is quiet.
1108 The driver doen't show link status messages.
1110 CONFIG_CALXEDA_XGMAC
1111 Support for the Calxeda XGMAC device
1114 Support for SMSC's LAN91C96 chips.
1116 CONFIG_LAN91C96_BASE
1117 Define this to hold the physical address
1118 of the LAN91C96's I/O space
1120 CONFIG_LAN91C96_USE_32_BIT
1121 Define this to enable 32 bit addressing
1124 Support for SMSC's LAN91C111 chip
1126 CONFIG_SMC91111_BASE
1127 Define this to hold the physical address
1128 of the device (I/O space)
1130 CONFIG_SMC_USE_32_BIT
1131 Define this if data bus is 32 bits
1133 CONFIG_SMC_USE_IOFUNCS
1134 Define this to use i/o functions instead of macros
1135 (some hardware wont work with macros)
1137 CONFIG_DRIVER_TI_EMAC
1138 Support for davinci emac
1140 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1141 Define this if you have more then 3 PHYs.
1144 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1146 CONFIG_FTGMAC100_EGIGA
1147 Define this to use GE link update with gigabit PHY.
1148 Define this if FTGMAC100 is connected to gigabit PHY.
1149 If your system has 10/100 PHY only, it might not occur
1150 wrong behavior. Because PHY usually return timeout or
1151 useless data when polling gigabit status and gigabit
1152 control registers. This behavior won't affect the
1153 correctnessof 10/100 link speed update.
1156 Support for SMSC's LAN911x and LAN921x chips
1159 Define this to hold the physical address
1160 of the device (I/O space)
1162 CONFIG_SMC911X_32_BIT
1163 Define this if data bus is 32 bits
1165 CONFIG_SMC911X_16_BIT
1166 Define this if data bus is 16 bits. If your processor
1167 automatically converts one 32 bit word to two 16 bit
1168 words you may also try CONFIG_SMC911X_32_BIT.
1171 Support for Renesas on-chip Ethernet controller
1173 CONFIG_SH_ETHER_USE_PORT
1174 Define the number of ports to be used
1176 CONFIG_SH_ETHER_PHY_ADDR
1177 Define the ETH PHY's address
1179 CONFIG_SH_ETHER_CACHE_WRITEBACK
1180 If this option is set, the driver enables cache flush.
1183 CONFIG_GENERIC_LPC_TPM
1184 Support for generic parallel port TPM devices. Only one device
1185 per system is supported at this time.
1187 CONFIG_TPM_TIS_BASE_ADDRESS
1188 Base address where the generic TPM device is mapped
1189 to. Contemporary x86 systems usually map it at
1193 At the moment only the UHCI host controller is
1194 supported (PIP405, MIP405, MPC5200); define
1195 CONFIG_USB_UHCI to enable it.
1196 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1197 and define CONFIG_USB_STORAGE to enable the USB
1200 Supported are USB Keyboards and USB Floppy drives
1202 MPC5200 USB requires additional defines:
1204 for 528 MHz Clock: 0x0001bbbb
1208 for differential drivers: 0x00001000
1209 for single ended drivers: 0x00005000
1210 for differential drivers on PSC3: 0x00000100
1211 for single ended drivers on PSC3: 0x00004100
1212 CONFIG_SYS_USB_EVENT_POLL
1213 May be defined to allow interrupt polling
1214 instead of using asynchronous interrupts
1216 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1217 txfilltuning field in the EHCI controller on reset.
1220 Define the below if you wish to use the USB console.
1221 Once firmware is rebuilt from a serial console issue the
1222 command "setenv stdin usbtty; setenv stdout usbtty" and
1223 attach your USB cable. The Unix command "dmesg" should print
1224 it has found a new device. The environment variable usbtty
1225 can be set to gserial or cdc_acm to enable your device to
1226 appear to a USB host as a Linux gserial device or a
1227 Common Device Class Abstract Control Model serial device.
1228 If you select usbtty = gserial you should be able to enumerate
1230 # modprobe usbserial vendor=0xVendorID product=0xProductID
1231 else if using cdc_acm, simply setting the environment
1232 variable usbtty to be cdc_acm should suffice. The following
1233 might be defined in YourBoardName.h
1236 Define this to build a UDC device
1239 Define this to have a tty type of device available to
1240 talk to the UDC device
1243 Define this to enable the high speed support for usb
1244 device and usbtty. If this feature is enabled, a routine
1245 int is_usbd_high_speed(void)
1246 also needs to be defined by the driver to dynamically poll
1247 whether the enumeration has succeded at high speed or full
1250 CONFIG_SYS_CONSOLE_IS_IN_ENV
1251 Define this if you want stdin, stdout &/or stderr to
1255 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1256 Derive USB clock from external clock "blah"
1257 - CONFIG_SYS_USB_EXTC_CLK 0x02
1259 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1260 Derive USB clock from brgclk
1261 - CONFIG_SYS_USB_BRG_CLK 0x04
1263 If you have a USB-IF assigned VendorID then you may wish to
1264 define your own vendor specific values either in BoardName.h
1265 or directly in usbd_vendor_info.h. If you don't define
1266 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1267 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1268 should pretend to be a Linux device to it's target host.
1270 CONFIG_USBD_MANUFACTURER
1271 Define this string as the name of your company for
1272 - CONFIG_USBD_MANUFACTURER "my company"
1274 CONFIG_USBD_PRODUCT_NAME
1275 Define this string as the name of your product
1276 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1278 CONFIG_USBD_VENDORID
1279 Define this as your assigned Vendor ID from the USB
1280 Implementors Forum. This *must* be a genuine Vendor ID
1281 to avoid polluting the USB namespace.
1282 - CONFIG_USBD_VENDORID 0xFFFF
1284 CONFIG_USBD_PRODUCTID
1285 Define this as the unique Product ID
1287 - CONFIG_USBD_PRODUCTID 0xFFFF
1289 - ULPI Layer Support:
1290 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1291 the generic ULPI layer. The generic layer accesses the ULPI PHY
1292 via the platform viewport, so you need both the genric layer and
1293 the viewport enabled. Currently only Chipidea/ARC based
1294 viewport is supported.
1295 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1296 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1297 If your ULPI phy needs a different reference clock than the
1298 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1299 the appropriate value in Hz.
1302 The MMC controller on the Intel PXA is supported. To
1303 enable this define CONFIG_MMC. The MMC can be
1304 accessed from the boot prompt by mapping the device
1305 to physical memory similar to flash. Command line is
1306 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1307 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1310 Support for Renesas on-chip MMCIF controller
1312 CONFIG_SH_MMCIF_ADDR
1313 Define the base address of MMCIF registers
1316 Define the clock frequency for MMCIF
1318 - Journaling Flash filesystem support:
1319 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1320 CONFIG_JFFS2_NAND_DEV
1321 Define these for a default partition on a NAND device
1323 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1324 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1325 Define these for a default partition on a NOR device
1327 CONFIG_SYS_JFFS_CUSTOM_PART
1328 Define this to create an own partition. You have to provide a
1329 function struct part_info* jffs2_part_info(int part_num)
1331 If you define only one JFFS2 partition you may also want to
1332 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1333 to disable the command chpart. This is the default when you
1334 have not defined a custom partition
1336 - FAT(File Allocation Table) filesystem write function support:
1339 Define this to enable support for saving memory data as a
1340 file in FAT formatted partition.
1342 This will also enable the command "fatwrite" enabling the
1343 user to write files to FAT.
1345 CBFS (Coreboot Filesystem) support
1348 Define this to enable support for reading from a Coreboot
1349 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1355 Define this to enable standard (PC-Style) keyboard
1359 Standard PC keyboard driver with US (is default) and
1360 GERMAN key layout (switch via environment 'keymap=de') support.
1361 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1362 for cfb_console. Supports cursor blinking.
1367 Define this to enable video support (for output to
1370 CONFIG_VIDEO_CT69000
1372 Enable Chips & Technologies 69000 Video chip
1374 CONFIG_VIDEO_SMI_LYNXEM
1375 Enable Silicon Motion SMI 712/710/810 Video chip. The
1376 video output is selected via environment 'videoout'
1377 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1380 For the CT69000 and SMI_LYNXEM drivers, videomode is
1381 selected via environment 'videomode'. Two different ways
1383 - "videomode=num" 'num' is a standard LiLo mode numbers.
1384 Following standard modes are supported (* is default):
1386 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1387 -------------+---------------------------------------------
1388 8 bits | 0x301* 0x303 0x305 0x161 0x307
1389 15 bits | 0x310 0x313 0x316 0x162 0x319
1390 16 bits | 0x311 0x314 0x317 0x163 0x31A
1391 24 bits | 0x312 0x315 0x318 ? 0x31B
1392 -------------+---------------------------------------------
1393 (i.e. setenv videomode 317; saveenv; reset;)
1395 - "videomode=bootargs" all the video parameters are parsed
1396 from the bootargs. (See drivers/video/videomodes.c)
1399 CONFIG_VIDEO_SED13806
1400 Enable Epson SED13806 driver. This driver supports 8bpp
1401 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1402 or CONFIG_VIDEO_SED13806_16BPP
1405 Enable the Freescale DIU video driver. Reference boards for
1406 SOCs that have a DIU should define this macro to enable DIU
1407 support, and should also define these other macros:
1413 CONFIG_VIDEO_SW_CURSOR
1414 CONFIG_VGA_AS_SINGLE_DEVICE
1416 CONFIG_VIDEO_BMP_LOGO
1418 The DIU driver will look for the 'video-mode' environment
1419 variable, and if defined, enable the DIU as a console during
1420 boot. See the documentation file README.video for a
1421 description of this variable.
1425 Enable the VGA video / BIOS for x86. The alternative if you
1426 are using coreboot is to use the coreboot frame buffer
1433 Define this to enable a custom keyboard support.
1434 This simply calls drv_keyboard_init() which must be
1435 defined in your board-specific files.
1436 The only board using this so far is RBC823.
1438 - LCD Support: CONFIG_LCD
1440 Define this to enable LCD support (for output to LCD
1441 display); also select one of the supported displays
1442 by defining one of these:
1446 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1448 CONFIG_NEC_NL6448AC33:
1450 NEC NL6448AC33-18. Active, color, single scan.
1452 CONFIG_NEC_NL6448BC20
1454 NEC NL6448BC20-08. 6.5", 640x480.
1455 Active, color, single scan.
1457 CONFIG_NEC_NL6448BC33_54
1459 NEC NL6448BC33-54. 10.4", 640x480.
1460 Active, color, single scan.
1464 Sharp 320x240. Active, color, single scan.
1465 It isn't 16x9, and I am not sure what it is.
1467 CONFIG_SHARP_LQ64D341
1469 Sharp LQ64D341 display, 640x480.
1470 Active, color, single scan.
1474 HLD1045 display, 640x480.
1475 Active, color, single scan.
1479 Optrex CBL50840-2 NF-FW 99 22 M5
1481 Hitachi LMG6912RPFC-00T
1485 320x240. Black & white.
1487 Normally display is black on white background; define
1488 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1490 CONFIG_LCD_ALIGNMENT
1492 Normally the LCD is page-aligned (tyically 4KB). If this is
1493 defined then the LCD will be aligned to this value instead.
1494 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1495 here, since it is cheaper to change data cache settings on
1496 a per-section basis.
1498 CONFIG_CONSOLE_SCROLL_LINES
1500 When the console need to be scrolled, this is the number of
1501 lines to scroll by. It defaults to 1. Increasing this makes
1502 the console jump but can help speed up operation when scrolling
1507 Support drawing of RLE8-compressed bitmaps on the LCD.
1511 Enables an 'i2c edid' command which can read EDID
1512 information over I2C from an attached LCD display.
1514 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1516 If this option is set, the environment is checked for
1517 a variable "splashimage". If found, the usual display
1518 of logo, copyright and system information on the LCD
1519 is suppressed and the BMP image at the address
1520 specified in "splashimage" is loaded instead. The
1521 console is redirected to the "nulldev", too. This
1522 allows for a "silent" boot where a splash screen is
1523 loaded very quickly after power-on.
1525 CONFIG_SPLASH_SCREEN_ALIGN
1527 If this option is set the splash image can be freely positioned
1528 on the screen. Environment variable "splashpos" specifies the
1529 position as "x,y". If a positive number is given it is used as
1530 number of pixel from left/top. If a negative number is given it
1531 is used as number of pixel from right/bottom. You can also
1532 specify 'm' for centering the image.
1535 setenv splashpos m,m
1536 => image at center of screen
1538 setenv splashpos 30,20
1539 => image at x = 30 and y = 20
1541 setenv splashpos -10,m
1542 => vertically centered image
1543 at x = dspWidth - bmpWidth - 9
1545 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1547 If this option is set, additionally to standard BMP
1548 images, gzipped BMP images can be displayed via the
1549 splashscreen support or the bmp command.
1551 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1553 If this option is set, 8-bit RLE compressed BMP images
1554 can be displayed via the splashscreen support or the
1557 - Do compresssing for memory range:
1560 If this option is set, it would use zlib deflate method
1561 to compress the specified memory at its best effort.
1563 - Compression support:
1566 If this option is set, support for bzip2 compressed
1567 images is included. If not, only uncompressed and gzip
1568 compressed images are supported.
1570 NOTE: the bzip2 algorithm requires a lot of RAM, so
1571 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1576 If this option is set, support for lzma compressed
1579 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1580 requires an amount of dynamic memory that is given by the
1583 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1585 Where lc and lp stand for, respectively, Literal context bits
1586 and Literal pos bits.
1588 This value is upper-bounded by 14MB in the worst case. Anyway,
1589 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1590 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1591 a very small buffer.
1593 Use the lzmainfo tool to determinate the lc and lp values and
1594 then calculate the amount of needed dynamic memory (ensuring
1595 the appropriate CONFIG_SYS_MALLOC_LEN value).
1600 The address of PHY on MII bus.
1602 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1604 The clock frequency of the MII bus
1608 If this option is set, support for speed/duplex
1609 detection of gigabit PHY is included.
1611 CONFIG_PHY_RESET_DELAY
1613 Some PHY like Intel LXT971A need extra delay after
1614 reset before any MII register access is possible.
1615 For such PHY, set this option to the usec delay
1616 required. (minimum 300usec for LXT971A)
1618 CONFIG_PHY_CMD_DELAY (ppc4xx)
1620 Some PHY like Intel LXT971A need extra delay after
1621 command issued before MII status register can be read
1631 Define a default value for Ethernet address to use
1632 for the respective Ethernet interface, in case this
1633 is not determined automatically.
1638 Define a default value for the IP address to use for
1639 the default Ethernet interface, in case this is not
1640 determined through e.g. bootp.
1641 (Environment variable "ipaddr")
1643 - Server IP address:
1646 Defines a default value for the IP address of a TFTP
1647 server to contact when using the "tftboot" command.
1648 (Environment variable "serverip")
1650 CONFIG_KEEP_SERVERADDR
1652 Keeps the server's MAC address, in the env 'serveraddr'
1653 for passing to bootargs (like Linux's netconsole option)
1655 - Gateway IP address:
1658 Defines a default value for the IP address of the
1659 default router where packets to other networks are
1661 (Environment variable "gatewayip")
1666 Defines a default value for the subnet mask (or
1667 routing prefix) which is used to determine if an IP
1668 address belongs to the local subnet or needs to be
1669 forwarded through a router.
1670 (Environment variable "netmask")
1672 - Multicast TFTP Mode:
1675 Defines whether you want to support multicast TFTP as per
1676 rfc-2090; for example to work with atftp. Lets lots of targets
1677 tftp down the same boot image concurrently. Note: the Ethernet
1678 driver in use must provide a function: mcast() to join/leave a
1681 - BOOTP Recovery Mode:
1682 CONFIG_BOOTP_RANDOM_DELAY
1684 If you have many targets in a network that try to
1685 boot using BOOTP, you may want to avoid that all
1686 systems send out BOOTP requests at precisely the same
1687 moment (which would happen for instance at recovery
1688 from a power failure, when all systems will try to
1689 boot, thus flooding the BOOTP server. Defining
1690 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1691 inserted before sending out BOOTP requests. The
1692 following delays are inserted then:
1694 1st BOOTP request: delay 0 ... 1 sec
1695 2nd BOOTP request: delay 0 ... 2 sec
1696 3rd BOOTP request: delay 0 ... 4 sec
1698 BOOTP requests: delay 0 ... 8 sec
1700 - DHCP Advanced Options:
1701 You can fine tune the DHCP functionality by defining
1702 CONFIG_BOOTP_* symbols:
1704 CONFIG_BOOTP_SUBNETMASK
1705 CONFIG_BOOTP_GATEWAY
1706 CONFIG_BOOTP_HOSTNAME
1707 CONFIG_BOOTP_NISDOMAIN
1708 CONFIG_BOOTP_BOOTPATH
1709 CONFIG_BOOTP_BOOTFILESIZE
1712 CONFIG_BOOTP_SEND_HOSTNAME
1713 CONFIG_BOOTP_NTPSERVER
1714 CONFIG_BOOTP_TIMEOFFSET
1715 CONFIG_BOOTP_VENDOREX
1716 CONFIG_BOOTP_MAY_FAIL
1718 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1719 environment variable, not the BOOTP server.
1721 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1722 after the configured retry count, the call will fail
1723 instead of starting over. This can be used to fail over
1724 to Link-local IP address configuration if the DHCP server
1727 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1728 serverip from a DHCP server, it is possible that more
1729 than one DNS serverip is offered to the client.
1730 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1731 serverip will be stored in the additional environment
1732 variable "dnsip2". The first DNS serverip is always
1733 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1736 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1737 to do a dynamic update of a DNS server. To do this, they
1738 need the hostname of the DHCP requester.
1739 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1740 of the "hostname" environment variable is passed as
1741 option 12 to the DHCP server.
1743 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1745 A 32bit value in microseconds for a delay between
1746 receiving a "DHCP Offer" and sending the "DHCP Request".
1747 This fixes a problem with certain DHCP servers that don't
1748 respond 100% of the time to a "DHCP request". E.g. On an
1749 AT91RM9200 processor running at 180MHz, this delay needed
1750 to be *at least* 15,000 usec before a Windows Server 2003
1751 DHCP server would reply 100% of the time. I recommend at
1752 least 50,000 usec to be safe. The alternative is to hope
1753 that one of the retries will be successful but note that
1754 the DHCP timeout and retry process takes a longer than
1757 - Link-local IP address negotiation:
1758 Negotiate with other link-local clients on the local network
1759 for an address that doesn't require explicit configuration.
1760 This is especially useful if a DHCP server cannot be guaranteed
1761 to exist in all environments that the device must operate.
1763 See doc/README.link-local for more information.
1766 CONFIG_CDP_DEVICE_ID
1768 The device id used in CDP trigger frames.
1770 CONFIG_CDP_DEVICE_ID_PREFIX
1772 A two character string which is prefixed to the MAC address
1777 A printf format string which contains the ascii name of
1778 the port. Normally is set to "eth%d" which sets
1779 eth0 for the first Ethernet, eth1 for the second etc.
1781 CONFIG_CDP_CAPABILITIES
1783 A 32bit integer which indicates the device capabilities;
1784 0x00000010 for a normal host which does not forwards.
1788 An ascii string containing the version of the software.
1792 An ascii string containing the name of the platform.
1796 A 32bit integer sent on the trigger.
1798 CONFIG_CDP_POWER_CONSUMPTION
1800 A 16bit integer containing the power consumption of the
1801 device in .1 of milliwatts.
1803 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1805 A byte containing the id of the VLAN.
1807 - Status LED: CONFIG_STATUS_LED
1809 Several configurations allow to display the current
1810 status using a LED. For instance, the LED will blink
1811 fast while running U-Boot code, stop blinking as
1812 soon as a reply to a BOOTP request was received, and
1813 start blinking slow once the Linux kernel is running
1814 (supported by a status LED driver in the Linux
1815 kernel). Defining CONFIG_STATUS_LED enables this
1818 - CAN Support: CONFIG_CAN_DRIVER
1820 Defining CONFIG_CAN_DRIVER enables CAN driver support
1821 on those systems that support this (optional)
1822 feature, like the TQM8xxL modules.
1824 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1826 These enable I2C serial bus commands. Defining either of
1827 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1828 include the appropriate I2C driver for the selected CPU.
1830 This will allow you to use i2c commands at the u-boot
1831 command line (as long as you set CONFIG_CMD_I2C in
1832 CONFIG_COMMANDS) and communicate with i2c based realtime
1833 clock chips. See common/cmd_i2c.c for a description of the
1834 command line interface.
1836 CONFIG_HARD_I2C selects a hardware I2C controller.
1838 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1839 bit-banging) driver instead of CPM or similar hardware
1842 There are several other quantities that must also be
1843 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1845 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1846 to be the frequency (in Hz) at which you wish your i2c bus
1847 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1848 the CPU's i2c node address).
1850 Now, the u-boot i2c code for the mpc8xx
1851 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1852 and so its address should therefore be cleared to 0 (See,
1853 eg, MPC823e User's Manual p.16-473). So, set
1854 CONFIG_SYS_I2C_SLAVE to 0.
1856 CONFIG_SYS_I2C_INIT_MPC5XXX
1858 When a board is reset during an i2c bus transfer
1859 chips might think that the current transfer is still
1860 in progress. Reset the slave devices by sending start
1861 commands until the slave device responds.
1863 That's all that's required for CONFIG_HARD_I2C.
1865 If you use the software i2c interface (CONFIG_SOFT_I2C)
1866 then the following macros need to be defined (examples are
1867 from include/configs/lwmon.h):
1871 (Optional). Any commands necessary to enable the I2C
1872 controller or configure ports.
1874 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1878 (Only for MPC8260 CPU). The I/O port to use (the code
1879 assumes both bits are on the same port). Valid values
1880 are 0..3 for ports A..D.
1884 The code necessary to make the I2C data line active
1885 (driven). If the data line is open collector, this
1888 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1892 The code necessary to make the I2C data line tri-stated
1893 (inactive). If the data line is open collector, this
1896 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1900 Code that returns TRUE if the I2C data line is high,
1903 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1907 If <bit> is TRUE, sets the I2C data line high. If it
1908 is FALSE, it clears it (low).
1910 eg: #define I2C_SDA(bit) \
1911 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1912 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1916 If <bit> is TRUE, sets the I2C clock line high. If it
1917 is FALSE, it clears it (low).
1919 eg: #define I2C_SCL(bit) \
1920 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1921 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1925 This delay is invoked four times per clock cycle so this
1926 controls the rate of data transfer. The data rate thus
1927 is 1 / (I2C_DELAY * 4). Often defined to be something
1930 #define I2C_DELAY udelay(2)
1932 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1934 If your arch supports the generic GPIO framework (asm/gpio.h),
1935 then you may alternatively define the two GPIOs that are to be
1936 used as SCL / SDA. Any of the previous I2C_xxx macros will
1937 have GPIO-based defaults assigned to them as appropriate.
1939 You should define these to the GPIO value as given directly to
1940 the generic GPIO functions.
1942 CONFIG_SYS_I2C_INIT_BOARD
1944 When a board is reset during an i2c bus transfer
1945 chips might think that the current transfer is still
1946 in progress. On some boards it is possible to access
1947 the i2c SCLK line directly, either by using the
1948 processor pin as a GPIO or by having a second pin
1949 connected to the bus. If this option is defined a
1950 custom i2c_init_board() routine in boards/xxx/board.c
1951 is run early in the boot sequence.
1953 CONFIG_SYS_I2C_BOARD_LATE_INIT
1955 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1956 defined a custom i2c_board_late_init() routine in
1957 boards/xxx/board.c is run AFTER the operations in i2c_init()
1958 is completed. This callpoint can be used to unreset i2c bus
1959 using CPU i2c controller register accesses for CPUs whose i2c
1960 controller provide such a method. It is called at the end of
1961 i2c_init() to allow i2c_init operations to setup the i2c bus
1962 controller on the CPU (e.g. setting bus speed & slave address).
1964 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1966 This option enables configuration of bi_iic_fast[] flags
1967 in u-boot bd_info structure based on u-boot environment
1968 variable "i2cfast". (see also i2cfast)
1970 CONFIG_I2C_MULTI_BUS
1972 This option allows the use of multiple I2C buses, each of which
1973 must have a controller. At any point in time, only one bus is
1974 active. To switch to a different bus, use the 'i2c dev' command.
1975 Note that bus numbering is zero-based.
1977 CONFIG_SYS_I2C_NOPROBES
1979 This option specifies a list of I2C devices that will be skipped
1980 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1981 is set, specify a list of bus-device pairs. Otherwise, specify
1982 a 1D array of device addresses
1985 #undef CONFIG_I2C_MULTI_BUS
1986 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1988 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1990 #define CONFIG_I2C_MULTI_BUS
1991 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1993 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1995 CONFIG_SYS_SPD_BUS_NUM
1997 If defined, then this indicates the I2C bus number for DDR SPD.
1998 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2000 CONFIG_SYS_RTC_BUS_NUM
2002 If defined, then this indicates the I2C bus number for the RTC.
2003 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2005 CONFIG_SYS_DTT_BUS_NUM
2007 If defined, then this indicates the I2C bus number for the DTT.
2008 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2010 CONFIG_SYS_I2C_DTT_ADDR:
2012 If defined, specifies the I2C address of the DTT device.
2013 If not defined, then U-Boot uses predefined value for
2014 specified DTT device.
2018 Define this option if you want to use Freescale's I2C driver in
2019 drivers/i2c/fsl_i2c.c.
2023 Define this option if you have I2C devices reached over 1 .. n
2024 I2C Muxes like the pca9544a. This option addes a new I2C
2025 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2026 new I2C Bus to the existing I2C Busses. If you select the
2027 new Bus with "i2c dev", u-bbot sends first the commandos for
2028 the muxes to activate this new "bus".
2030 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2034 Adding a new I2C Bus reached over 2 pca9544a muxes
2035 The First mux with address 70 and channel 6
2036 The Second mux with address 71 and channel 4
2038 => i2c bus pca9544a:70:6:pca9544a:71:4
2040 Use the "i2c bus" command without parameter, to get a list
2041 of I2C Busses with muxes:
2044 Busses reached over muxes:
2046 reached over Mux(es):
2049 reached over Mux(es):
2054 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2055 u-boot first sends the command to the mux@70 to enable
2056 channel 6, and then the command to the mux@71 to enable
2059 After that, you can use the "normal" i2c commands as
2060 usual to communicate with your I2C devices behind
2063 This option is actually implemented for the bitbanging
2064 algorithm in common/soft_i2c.c and for the Hardware I2C
2065 Bus on the MPC8260. But it should be not so difficult
2066 to add this option to other architectures.
2068 CONFIG_SOFT_I2C_READ_REPEATED_START
2070 defining this will force the i2c_read() function in
2071 the soft_i2c driver to perform an I2C repeated start
2072 between writing the address pointer and reading the
2073 data. If this define is omitted the default behaviour
2074 of doing a stop-start sequence will be used. Most I2C
2075 devices can use either method, but some require one or
2078 - SPI Support: CONFIG_SPI
2080 Enables SPI driver (so far only tested with
2081 SPI EEPROM, also an instance works with Crystal A/D and
2082 D/As on the SACSng board)
2086 Enables the driver for SPI controller on SuperH. Currently
2087 only SH7757 is supported.
2091 Enables extended (16-bit) SPI EEPROM addressing.
2092 (symmetrical to CONFIG_I2C_X)
2096 Enables a software (bit-bang) SPI driver rather than
2097 using hardware support. This is a general purpose
2098 driver that only requires three general I/O port pins
2099 (two outputs, one input) to function. If this is
2100 defined, the board configuration must define several
2101 SPI configuration items (port pins to use, etc). For
2102 an example, see include/configs/sacsng.h.
2106 Enables a hardware SPI driver for general-purpose reads
2107 and writes. As with CONFIG_SOFT_SPI, the board configuration
2108 must define a list of chip-select function pointers.
2109 Currently supported on some MPC8xxx processors. For an
2110 example, see include/configs/mpc8349emds.h.
2114 Enables the driver for the SPI controllers on i.MX and MXC
2115 SoCs. Currently i.MX31/35/51 are supported.
2117 - FPGA Support: CONFIG_FPGA
2119 Enables FPGA subsystem.
2121 CONFIG_FPGA_<vendor>
2123 Enables support for specific chip vendors.
2126 CONFIG_FPGA_<family>
2128 Enables support for FPGA family.
2129 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2133 Specify the number of FPGA devices to support.
2135 CONFIG_SYS_FPGA_PROG_FEEDBACK
2137 Enable printing of hash marks during FPGA configuration.
2139 CONFIG_SYS_FPGA_CHECK_BUSY
2141 Enable checks on FPGA configuration interface busy
2142 status by the configuration function. This option
2143 will require a board or device specific function to
2148 If defined, a function that provides delays in the FPGA
2149 configuration driver.
2151 CONFIG_SYS_FPGA_CHECK_CTRLC
2152 Allow Control-C to interrupt FPGA configuration
2154 CONFIG_SYS_FPGA_CHECK_ERROR
2156 Check for configuration errors during FPGA bitfile
2157 loading. For example, abort during Virtex II
2158 configuration if the INIT_B line goes low (which
2159 indicated a CRC error).
2161 CONFIG_SYS_FPGA_WAIT_INIT
2163 Maximum time to wait for the INIT_B line to deassert
2164 after PROB_B has been deasserted during a Virtex II
2165 FPGA configuration sequence. The default time is 500
2168 CONFIG_SYS_FPGA_WAIT_BUSY
2170 Maximum time to wait for BUSY to deassert during
2171 Virtex II FPGA configuration. The default is 5 ms.
2173 CONFIG_SYS_FPGA_WAIT_CONFIG
2175 Time to wait after FPGA configuration. The default is
2178 - Configuration Management:
2181 If defined, this string will be added to the U-Boot
2182 version information (U_BOOT_VERSION)
2184 - Vendor Parameter Protection:
2186 U-Boot considers the values of the environment
2187 variables "serial#" (Board Serial Number) and
2188 "ethaddr" (Ethernet Address) to be parameters that
2189 are set once by the board vendor / manufacturer, and
2190 protects these variables from casual modification by
2191 the user. Once set, these variables are read-only,
2192 and write or delete attempts are rejected. You can
2193 change this behaviour:
2195 If CONFIG_ENV_OVERWRITE is #defined in your config
2196 file, the write protection for vendor parameters is
2197 completely disabled. Anybody can change or delete
2200 Alternatively, if you #define _both_ CONFIG_ETHADDR
2201 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2202 Ethernet address is installed in the environment,
2203 which can be changed exactly ONCE by the user. [The
2204 serial# is unaffected by this, i. e. it remains
2207 The same can be accomplished in a more flexible way
2208 for any variable by configuring the type of access
2209 to allow for those variables in the ".flags" variable
2210 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2215 Define this variable to enable the reservation of
2216 "protected RAM", i. e. RAM which is not overwritten
2217 by U-Boot. Define CONFIG_PRAM to hold the number of
2218 kB you want to reserve for pRAM. You can overwrite
2219 this default value by defining an environment
2220 variable "pram" to the number of kB you want to
2221 reserve. Note that the board info structure will
2222 still show the full amount of RAM. If pRAM is
2223 reserved, a new environment variable "mem" will
2224 automatically be defined to hold the amount of
2225 remaining RAM in a form that can be passed as boot
2226 argument to Linux, for instance like that:
2228 setenv bootargs ... mem=\${mem}
2231 This way you can tell Linux not to use this memory,
2232 either, which results in a memory region that will
2233 not be affected by reboots.
2235 *WARNING* If your board configuration uses automatic
2236 detection of the RAM size, you must make sure that
2237 this memory test is non-destructive. So far, the
2238 following board configurations are known to be
2241 IVMS8, IVML24, SPD8xx, TQM8xxL,
2242 HERMES, IP860, RPXlite, LWMON,
2245 - Access to physical memory region (> 4GB)
2246 Some basic support is provided for operations on memory not
2247 normally accessible to U-Boot - e.g. some architectures
2248 support access to more than 4GB of memory on 32-bit
2249 machines using physical address extension or similar.
2250 Define CONFIG_PHYSMEM to access this basic support, which
2251 currently only supports clearing the memory.
2256 Define this variable to stop the system in case of a
2257 fatal error, so that you have to reset it manually.
2258 This is probably NOT a good idea for an embedded
2259 system where you want the system to reboot
2260 automatically as fast as possible, but it may be
2261 useful during development since you can try to debug
2262 the conditions that lead to the situation.
2264 CONFIG_NET_RETRY_COUNT
2266 This variable defines the number of retries for
2267 network operations like ARP, RARP, TFTP, or BOOTP
2268 before giving up the operation. If not defined, a
2269 default value of 5 is used.
2273 Timeout waiting for an ARP reply in milliseconds.
2277 Timeout in milliseconds used in NFS protocol.
2278 If you encounter "ERROR: Cannot umount" in nfs command,
2279 try longer timeout such as
2280 #define CONFIG_NFS_TIMEOUT 10000UL
2282 - Command Interpreter:
2283 CONFIG_AUTO_COMPLETE
2285 Enable auto completion of commands using TAB.
2287 Note that this feature has NOT been implemented yet
2288 for the "hush" shell.
2291 CONFIG_SYS_HUSH_PARSER
2293 Define this variable to enable the "hush" shell (from
2294 Busybox) as command line interpreter, thus enabling
2295 powerful command line syntax like
2296 if...then...else...fi conditionals or `&&' and '||'
2297 constructs ("shell scripts").
2299 If undefined, you get the old, much simpler behaviour
2300 with a somewhat smaller memory footprint.
2303 CONFIG_SYS_PROMPT_HUSH_PS2
2305 This defines the secondary prompt string, which is
2306 printed when the command interpreter needs more input
2307 to complete a command. Usually "> ".
2311 In the current implementation, the local variables
2312 space and global environment variables space are
2313 separated. Local variables are those you define by
2314 simply typing `name=value'. To access a local
2315 variable later on, you have write `$name' or
2316 `${name}'; to execute the contents of a variable
2317 directly type `$name' at the command prompt.
2319 Global environment variables are those you use
2320 setenv/printenv to work with. To run a command stored
2321 in such a variable, you need to use the run command,
2322 and you must not use the '$' sign to access them.
2324 To store commands and special characters in a
2325 variable, please use double quotation marks
2326 surrounding the whole text of the variable, instead
2327 of the backslashes before semicolons and special
2330 - Commandline Editing and History:
2331 CONFIG_CMDLINE_EDITING
2333 Enable editing and History functions for interactive
2334 commandline input operations
2336 - Default Environment:
2337 CONFIG_EXTRA_ENV_SETTINGS
2339 Define this to contain any number of null terminated
2340 strings (variable = value pairs) that will be part of
2341 the default environment compiled into the boot image.
2343 For example, place something like this in your
2344 board's config file:
2346 #define CONFIG_EXTRA_ENV_SETTINGS \
2350 Warning: This method is based on knowledge about the
2351 internal format how the environment is stored by the
2352 U-Boot code. This is NOT an official, exported
2353 interface! Although it is unlikely that this format
2354 will change soon, there is no guarantee either.
2355 You better know what you are doing here.
2357 Note: overly (ab)use of the default environment is
2358 discouraged. Make sure to check other ways to preset
2359 the environment like the "source" command or the
2362 CONFIG_ENV_VARS_UBOOT_CONFIG
2364 Define this in order to add variables describing the
2365 U-Boot build configuration to the default environment.
2366 These will be named arch, cpu, board, vendor, and soc.
2368 Enabling this option will cause the following to be defined:
2376 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2378 Define this in order to add variables describing certain
2379 run-time determined information about the hardware to the
2380 environment. These will be named board_name, board_rev.
2382 CONFIG_DELAY_ENVIRONMENT
2384 Normally the environment is loaded when the board is
2385 intialised so that it is available to U-Boot. This inhibits
2386 that so that the environment is not available until
2387 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2388 this is instead controlled by the value of
2389 /config/load-environment.
2391 - DataFlash Support:
2392 CONFIG_HAS_DATAFLASH
2394 Defining this option enables DataFlash features and
2395 allows to read/write in Dataflash via the standard
2398 - Serial Flash support
2401 Defining this option enables SPI flash commands
2402 'sf probe/read/write/erase/update'.
2404 Usage requires an initial 'probe' to define the serial
2405 flash parameters, followed by read/write/erase/update
2408 The following defaults may be provided by the platform
2409 to handle the common case when only a single serial
2410 flash is present on the system.
2412 CONFIG_SF_DEFAULT_BUS Bus identifier
2413 CONFIG_SF_DEFAULT_CS Chip-select
2414 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2415 CONFIG_SF_DEFAULT_SPEED in Hz
2417 - SystemACE Support:
2420 Adding this option adds support for Xilinx SystemACE
2421 chips attached via some sort of local bus. The address
2422 of the chip must also be defined in the
2423 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2425 #define CONFIG_SYSTEMACE
2426 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2428 When SystemACE support is added, the "ace" device type
2429 becomes available to the fat commands, i.e. fatls.
2431 - TFTP Fixed UDP Port:
2434 If this is defined, the environment variable tftpsrcp
2435 is used to supply the TFTP UDP source port value.
2436 If tftpsrcp isn't defined, the normal pseudo-random port
2437 number generator is used.
2439 Also, the environment variable tftpdstp is used to supply
2440 the TFTP UDP destination port value. If tftpdstp isn't
2441 defined, the normal port 69 is used.
2443 The purpose for tftpsrcp is to allow a TFTP server to
2444 blindly start the TFTP transfer using the pre-configured
2445 target IP address and UDP port. This has the effect of
2446 "punching through" the (Windows XP) firewall, allowing
2447 the remainder of the TFTP transfer to proceed normally.
2448 A better solution is to properly configure the firewall,
2449 but sometimes that is not allowed.
2454 This enables a generic 'hash' command which can produce
2455 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2459 Enable the hash verify command (hash -v). This adds to code
2462 CONFIG_SHA1 - support SHA1 hashing
2463 CONFIG_SHA256 - support SHA256 hashing
2465 Note: There is also a sha1sum command, which should perhaps
2466 be deprecated in favour of 'hash sha1'.
2468 - Show boot progress:
2469 CONFIG_SHOW_BOOT_PROGRESS
2471 Defining this option allows to add some board-
2472 specific code (calling a user-provided function
2473 "show_boot_progress(int)") that enables you to show
2474 the system's boot progress on some display (for
2475 example, some LED's) on your board. At the moment,
2476 the following checkpoints are implemented:
2478 - Detailed boot stage timing
2480 Define this option to get detailed timing of each stage
2481 of the boot process.
2483 CONFIG_BOOTSTAGE_USER_COUNT
2484 This is the number of available user bootstage records.
2485 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2486 a new ID will be allocated from this stash. If you exceed
2487 the limit, recording will stop.
2489 CONFIG_BOOTSTAGE_REPORT
2490 Define this to print a report before boot, similar to this:
2492 Timer summary in microseconds:
2495 3,575,678 3,575,678 board_init_f start
2496 3,575,695 17 arch_cpu_init A9
2497 3,575,777 82 arch_cpu_init done
2498 3,659,598 83,821 board_init_r start
2499 3,910,375 250,777 main_loop
2500 29,916,167 26,005,792 bootm_start
2501 30,361,327 445,160 start_kernel
2503 CONFIG_CMD_BOOTSTAGE
2504 Add a 'bootstage' command which supports printing a report
2505 and un/stashing of bootstage data.
2507 CONFIG_BOOTSTAGE_FDT
2508 Stash the bootstage information in the FDT. A root 'bootstage'
2509 node is created with each bootstage id as a child. Each child
2510 has a 'name' property and either 'mark' containing the
2511 mark time in microsecond, or 'accum' containing the
2512 accumulated time for that bootstage id in microseconds.
2517 name = "board_init_f";
2526 Code in the Linux kernel can find this in /proc/devicetree.
2528 Legacy uImage format:
2531 1 common/cmd_bootm.c before attempting to boot an image
2532 -1 common/cmd_bootm.c Image header has bad magic number
2533 2 common/cmd_bootm.c Image header has correct magic number
2534 -2 common/cmd_bootm.c Image header has bad checksum
2535 3 common/cmd_bootm.c Image header has correct checksum
2536 -3 common/cmd_bootm.c Image data has bad checksum
2537 4 common/cmd_bootm.c Image data has correct checksum
2538 -4 common/cmd_bootm.c Image is for unsupported architecture
2539 5 common/cmd_bootm.c Architecture check OK
2540 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2541 6 common/cmd_bootm.c Image Type check OK
2542 -6 common/cmd_bootm.c gunzip uncompression error
2543 -7 common/cmd_bootm.c Unimplemented compression type
2544 7 common/cmd_bootm.c Uncompression OK
2545 8 common/cmd_bootm.c No uncompress/copy overwrite error
2546 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2548 9 common/image.c Start initial ramdisk verification
2549 -10 common/image.c Ramdisk header has bad magic number
2550 -11 common/image.c Ramdisk header has bad checksum
2551 10 common/image.c Ramdisk header is OK
2552 -12 common/image.c Ramdisk data has bad checksum
2553 11 common/image.c Ramdisk data has correct checksum
2554 12 common/image.c Ramdisk verification complete, start loading
2555 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2556 13 common/image.c Start multifile image verification
2557 14 common/image.c No initial ramdisk, no multifile, continue.
2559 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2561 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2562 -31 post/post.c POST test failed, detected by post_output_backlog()
2563 -32 post/post.c POST test failed, detected by post_run_single()
2565 34 common/cmd_doc.c before loading a Image from a DOC device
2566 -35 common/cmd_doc.c Bad usage of "doc" command
2567 35 common/cmd_doc.c correct usage of "doc" command
2568 -36 common/cmd_doc.c No boot device
2569 36 common/cmd_doc.c correct boot device
2570 -37 common/cmd_doc.c Unknown Chip ID on boot device
2571 37 common/cmd_doc.c correct chip ID found, device available
2572 -38 common/cmd_doc.c Read Error on boot device
2573 38 common/cmd_doc.c reading Image header from DOC device OK
2574 -39 common/cmd_doc.c Image header has bad magic number
2575 39 common/cmd_doc.c Image header has correct magic number
2576 -40 common/cmd_doc.c Error reading Image from DOC device
2577 40 common/cmd_doc.c Image header has correct magic number
2578 41 common/cmd_ide.c before loading a Image from a IDE device
2579 -42 common/cmd_ide.c Bad usage of "ide" command
2580 42 common/cmd_ide.c correct usage of "ide" command
2581 -43 common/cmd_ide.c No boot device
2582 43 common/cmd_ide.c boot device found
2583 -44 common/cmd_ide.c Device not available
2584 44 common/cmd_ide.c Device available
2585 -45 common/cmd_ide.c wrong partition selected
2586 45 common/cmd_ide.c partition selected
2587 -46 common/cmd_ide.c Unknown partition table
2588 46 common/cmd_ide.c valid partition table found
2589 -47 common/cmd_ide.c Invalid partition type
2590 47 common/cmd_ide.c correct partition type
2591 -48 common/cmd_ide.c Error reading Image Header on boot device
2592 48 common/cmd_ide.c reading Image Header from IDE device OK
2593 -49 common/cmd_ide.c Image header has bad magic number
2594 49 common/cmd_ide.c Image header has correct magic number
2595 -50 common/cmd_ide.c Image header has bad checksum
2596 50 common/cmd_ide.c Image header has correct checksum
2597 -51 common/cmd_ide.c Error reading Image from IDE device
2598 51 common/cmd_ide.c reading Image from IDE device OK
2599 52 common/cmd_nand.c before loading a Image from a NAND device
2600 -53 common/cmd_nand.c Bad usage of "nand" command
2601 53 common/cmd_nand.c correct usage of "nand" command
2602 -54 common/cmd_nand.c No boot device
2603 54 common/cmd_nand.c boot device found
2604 -55 common/cmd_nand.c Unknown Chip ID on boot device
2605 55 common/cmd_nand.c correct chip ID found, device available
2606 -56 common/cmd_nand.c Error reading Image Header on boot device
2607 56 common/cmd_nand.c reading Image Header from NAND device OK
2608 -57 common/cmd_nand.c Image header has bad magic number
2609 57 common/cmd_nand.c Image header has correct magic number
2610 -58 common/cmd_nand.c Error reading Image from NAND device
2611 58 common/cmd_nand.c reading Image from NAND device OK
2613 -60 common/env_common.c Environment has a bad CRC, using default
2615 64 net/eth.c starting with Ethernet configuration.
2616 -64 net/eth.c no Ethernet found.
2617 65 net/eth.c Ethernet found.
2619 -80 common/cmd_net.c usage wrong
2620 80 common/cmd_net.c before calling NetLoop()
2621 -81 common/cmd_net.c some error in NetLoop() occurred
2622 81 common/cmd_net.c NetLoop() back without error
2623 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2624 82 common/cmd_net.c trying automatic boot
2625 83 common/cmd_net.c running "source" command
2626 -83 common/cmd_net.c some error in automatic boot or "source" command
2627 84 common/cmd_net.c end without errors
2632 100 common/cmd_bootm.c Kernel FIT Image has correct format
2633 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2634 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2635 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2636 102 common/cmd_bootm.c Kernel unit name specified
2637 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2638 103 common/cmd_bootm.c Found configuration node
2639 104 common/cmd_bootm.c Got kernel subimage node offset
2640 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2641 105 common/cmd_bootm.c Kernel subimage hash verification OK
2642 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2643 106 common/cmd_bootm.c Architecture check OK
2644 -106 common/cmd_bootm.c Kernel subimage has wrong type
2645 107 common/cmd_bootm.c Kernel subimage type OK
2646 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2647 108 common/cmd_bootm.c Got kernel subimage data/size
2648 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2649 -109 common/cmd_bootm.c Can't get kernel subimage type
2650 -110 common/cmd_bootm.c Can't get kernel subimage comp
2651 -111 common/cmd_bootm.c Can't get kernel subimage os
2652 -112 common/cmd_bootm.c Can't get kernel subimage load address
2653 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2655 120 common/image.c Start initial ramdisk verification
2656 -120 common/image.c Ramdisk FIT image has incorrect format
2657 121 common/image.c Ramdisk FIT image has correct format
2658 122 common/image.c No ramdisk subimage unit name, using configuration
2659 -122 common/image.c Can't get configuration for ramdisk subimage
2660 123 common/image.c Ramdisk unit name specified
2661 -124 common/image.c Can't get ramdisk subimage node offset
2662 125 common/image.c Got ramdisk subimage node offset
2663 -125 common/image.c Ramdisk subimage hash verification failed
2664 126 common/image.c Ramdisk subimage hash verification OK
2665 -126 common/image.c Ramdisk subimage for unsupported architecture
2666 127 common/image.c Architecture check OK
2667 -127 common/image.c Can't get ramdisk subimage data/size
2668 128 common/image.c Got ramdisk subimage data/size
2669 129 common/image.c Can't get ramdisk load address
2670 -129 common/image.c Got ramdisk load address
2672 -130 common/cmd_doc.c Incorrect FIT image format
2673 131 common/cmd_doc.c FIT image format OK
2675 -140 common/cmd_ide.c Incorrect FIT image format
2676 141 common/cmd_ide.c FIT image format OK
2678 -150 common/cmd_nand.c Incorrect FIT image format
2679 151 common/cmd_nand.c FIT image format OK
2681 - FIT image support:
2683 Enable support for the FIT uImage format.
2685 CONFIG_FIT_BEST_MATCH
2686 When no configuration is explicitly selected, default to the
2687 one whose fdt's compatibility field best matches that of
2688 U-Boot itself. A match is considered "best" if it matches the
2689 most specific compatibility entry of U-Boot's fdt's root node.
2690 The order of entries in the configuration's fdt is ignored.
2692 - Standalone program support:
2693 CONFIG_STANDALONE_LOAD_ADDR
2695 This option defines a board specific value for the
2696 address where standalone program gets loaded, thus
2697 overwriting the architecture dependent default
2700 - Frame Buffer Address:
2703 Define CONFIG_FB_ADDR if you want to use specific
2704 address for frame buffer.
2705 Then system will reserve the frame buffer address to
2706 defined address instead of lcd_setmem (this function
2707 grabs the memory for frame buffer by panel's size).
2709 Please see board_init_f function.
2711 - Automatic software updates via TFTP server
2713 CONFIG_UPDATE_TFTP_CNT_MAX
2714 CONFIG_UPDATE_TFTP_MSEC_MAX
2716 These options enable and control the auto-update feature;
2717 for a more detailed description refer to doc/README.update.
2719 - MTD Support (mtdparts command, UBI support)
2722 Adds the MTD device infrastructure from the Linux kernel.
2723 Needed for mtdparts command support.
2725 CONFIG_MTD_PARTITIONS
2727 Adds the MTD partitioning infrastructure from the Linux
2728 kernel. Needed for UBI support.
2732 Enable building of SPL globally.
2735 LDSCRIPT for linking the SPL binary.
2738 Maximum binary size (text, data and rodata) of the SPL binary.
2740 CONFIG_SPL_TEXT_BASE
2741 TEXT_BASE for linking the SPL binary.
2743 CONFIG_SPL_RELOC_TEXT_BASE
2744 Address to relocate to. If unspecified, this is equal to
2745 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2747 CONFIG_SPL_BSS_START_ADDR
2748 Link address for the BSS within the SPL binary.
2750 CONFIG_SPL_BSS_MAX_SIZE
2751 Maximum binary size of the BSS section of the SPL binary.
2754 Adress of the start of the stack SPL will use
2756 CONFIG_SPL_RELOC_STACK
2757 Adress of the start of the stack SPL will use after
2758 relocation. If unspecified, this is equal to
2761 CONFIG_SYS_SPL_MALLOC_START
2762 Starting address of the malloc pool used in SPL.
2764 CONFIG_SYS_SPL_MALLOC_SIZE
2765 The size of the malloc pool used in SPL.
2767 CONFIG_SPL_FRAMEWORK
2768 Enable the SPL framework under common/. This framework
2769 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2770 NAND loading of the Linux Kernel.
2772 CONFIG_SPL_DISPLAY_PRINT
2773 For ARM, enable an optional function to print more information
2774 about the running system.
2776 CONFIG_SPL_INIT_MINIMAL
2777 Arch init code should be built for a very small image
2779 CONFIG_SPL_LIBCOMMON_SUPPORT
2780 Support for common/libcommon.o in SPL binary
2782 CONFIG_SPL_LIBDISK_SUPPORT
2783 Support for disk/libdisk.o in SPL binary
2785 CONFIG_SPL_I2C_SUPPORT
2786 Support for drivers/i2c/libi2c.o in SPL binary
2788 CONFIG_SPL_GPIO_SUPPORT
2789 Support for drivers/gpio/libgpio.o in SPL binary
2791 CONFIG_SPL_MMC_SUPPORT
2792 Support for drivers/mmc/libmmc.o in SPL binary
2794 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2795 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2796 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2797 Address, size and partition on the MMC to load U-Boot from
2798 when the MMC is being used in raw mode.
2800 CONFIG_SPL_FAT_SUPPORT
2801 Support for fs/fat/libfat.o in SPL binary
2803 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2804 Filename to read to load U-Boot when reading from FAT
2806 CONFIG_SPL_NAND_BASE
2807 Include nand_base.c in the SPL. Requires
2808 CONFIG_SPL_NAND_DRIVERS.
2810 CONFIG_SPL_NAND_DRIVERS
2811 SPL uses normal NAND drivers, not minimal drivers.
2814 Include standard software ECC in the SPL
2816 CONFIG_SPL_NAND_SIMPLE
2817 Support for NAND boot using simple NAND drivers that
2818 expose the cmd_ctrl() interface.
2820 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2821 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2822 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2823 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2824 CONFIG_SYS_NAND_ECCBYTES
2825 Defines the size and behavior of the NAND that SPL uses
2828 CONFIG_SYS_NAND_U_BOOT_OFFS
2829 Location in NAND to read U-Boot from
2831 CONFIG_SYS_NAND_U_BOOT_DST
2832 Location in memory to load U-Boot to
2834 CONFIG_SYS_NAND_U_BOOT_SIZE
2835 Size of image to load
2837 CONFIG_SYS_NAND_U_BOOT_START
2838 Entry point in loaded image to jump to
2840 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2841 Define this if you need to first read the OOB and then the
2842 data. This is used for example on davinci plattforms.
2844 CONFIG_SPL_OMAP3_ID_NAND
2845 Support for an OMAP3-specific set of functions to return the
2846 ID and MFR of the first attached NAND chip, if present.
2848 CONFIG_SPL_SERIAL_SUPPORT
2849 Support for drivers/serial/libserial.o in SPL binary
2851 CONFIG_SPL_SPI_FLASH_SUPPORT
2852 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2854 CONFIG_SPL_SPI_SUPPORT
2855 Support for drivers/spi/libspi.o in SPL binary
2857 CONFIG_SPL_RAM_DEVICE
2858 Support for running image already present in ram, in SPL binary
2860 CONFIG_SPL_LIBGENERIC_SUPPORT
2861 Support for lib/libgeneric.o in SPL binary
2864 Final target image containing SPL and payload. Some SPLs
2865 use an arch-specific makefile fragment instead, for
2866 example if more than one image needs to be produced.
2871 [so far only for SMDK2400 boards]
2873 - Modem support enable:
2874 CONFIG_MODEM_SUPPORT
2876 - RTS/CTS Flow control enable:
2879 - Modem debug support:
2880 CONFIG_MODEM_SUPPORT_DEBUG
2882 Enables debugging stuff (char screen[1024], dbg())
2883 for modem support. Useful only with BDI2000.
2885 - Interrupt support (PPC):
2887 There are common interrupt_init() and timer_interrupt()
2888 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2889 for CPU specific initialization. interrupt_init_cpu()
2890 should set decrementer_count to appropriate value. If
2891 CPU resets decrementer automatically after interrupt
2892 (ppc4xx) it should set decrementer_count to zero.
2893 timer_interrupt() calls timer_interrupt_cpu() for CPU
2894 specific handling. If board has watchdog / status_led
2895 / other_activity_monitor it works automatically from
2896 general timer_interrupt().
2900 In the target system modem support is enabled when a
2901 specific key (key combination) is pressed during
2902 power-on. Otherwise U-Boot will boot normally
2903 (autoboot). The key_pressed() function is called from
2904 board_init(). Currently key_pressed() is a dummy
2905 function, returning 1 and thus enabling modem
2908 If there are no modem init strings in the
2909 environment, U-Boot proceed to autoboot; the
2910 previous output (banner, info printfs) will be
2913 See also: doc/README.Modem
2915 Board initialization settings:
2916 ------------------------------
2918 During Initialization u-boot calls a number of board specific functions
2919 to allow the preparation of board specific prerequisites, e.g. pin setup
2920 before drivers are initialized. To enable these callbacks the
2921 following configuration macros have to be defined. Currently this is
2922 architecture specific, so please check arch/your_architecture/lib/board.c
2923 typically in board_init_f() and board_init_r().
2925 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2926 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2927 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2928 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2930 Configuration Settings:
2931 -----------------------
2933 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2934 undefine this when you're short of memory.
2936 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2937 width of the commands listed in the 'help' command output.
2939 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2940 prompt for user input.
2942 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2944 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2946 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2948 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2949 the application (usually a Linux kernel) when it is
2952 - CONFIG_SYS_BAUDRATE_TABLE:
2953 List of legal baudrate settings for this board.
2955 - CONFIG_SYS_CONSOLE_INFO_QUIET
2956 Suppress display of console information at boot.
2958 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2959 If the board specific function
2960 extern int overwrite_console (void);
2961 returns 1, the stdin, stderr and stdout are switched to the
2962 serial port, else the settings in the environment are used.
2964 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2965 Enable the call to overwrite_console().
2967 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2968 Enable overwrite of previous console environment settings.
2970 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2971 Begin and End addresses of the area used by the
2974 - CONFIG_SYS_ALT_MEMTEST:
2975 Enable an alternate, more extensive memory test.
2977 - CONFIG_SYS_MEMTEST_SCRATCH:
2978 Scratch address used by the alternate memory test
2979 You only need to set this if address zero isn't writeable
2981 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2982 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2983 this specified memory area will get subtracted from the top
2984 (end) of RAM and won't get "touched" at all by U-Boot. By
2985 fixing up gd->ram_size the Linux kernel should gets passed
2986 the now "corrected" memory size and won't touch it either.
2987 This should work for arch/ppc and arch/powerpc. Only Linux
2988 board ports in arch/powerpc with bootwrapper support that
2989 recalculate the memory size from the SDRAM controller setup
2990 will have to get fixed in Linux additionally.
2992 This option can be used as a workaround for the 440EPx/GRx
2993 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2996 WARNING: Please make sure that this value is a multiple of
2997 the Linux page size (normally 4k). If this is not the case,
2998 then the end address of the Linux memory will be located at a
2999 non page size aligned address and this could cause major
3002 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3003 Enable temporary baudrate change while serial download
3005 - CONFIG_SYS_SDRAM_BASE:
3006 Physical start address of SDRAM. _Must_ be 0 here.
3008 - CONFIG_SYS_MBIO_BASE:
3009 Physical start address of Motherboard I/O (if using a
3012 - CONFIG_SYS_FLASH_BASE:
3013 Physical start address of Flash memory.
3015 - CONFIG_SYS_MONITOR_BASE:
3016 Physical start address of boot monitor code (set by
3017 make config files to be same as the text base address
3018 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3019 CONFIG_SYS_FLASH_BASE when booting from flash.
3021 - CONFIG_SYS_MONITOR_LEN:
3022 Size of memory reserved for monitor code, used to
3023 determine _at_compile_time_ (!) if the environment is
3024 embedded within the U-Boot image, or in a separate
3027 - CONFIG_SYS_MALLOC_LEN:
3028 Size of DRAM reserved for malloc() use.
3030 - CONFIG_SYS_BOOTM_LEN:
3031 Normally compressed uImages are limited to an
3032 uncompressed size of 8 MBytes. If this is not enough,
3033 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3034 to adjust this setting to your needs.
3036 - CONFIG_SYS_BOOTMAPSZ:
3037 Maximum size of memory mapped by the startup code of
3038 the Linux kernel; all data that must be processed by
3039 the Linux kernel (bd_info, boot arguments, FDT blob if
3040 used) must be put below this limit, unless "bootm_low"
3041 enviroment variable is defined and non-zero. In such case
3042 all data for the Linux kernel must be between "bootm_low"
3043 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3044 variable "bootm_mapsize" will override the value of
3045 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3046 then the value in "bootm_size" will be used instead.
3048 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3049 Enable initrd_high functionality. If defined then the
3050 initrd_high feature is enabled and the bootm ramdisk subcommand
3053 - CONFIG_SYS_BOOT_GET_CMDLINE:
3054 Enables allocating and saving kernel cmdline in space between
3055 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3057 - CONFIG_SYS_BOOT_GET_KBD:
3058 Enables allocating and saving a kernel copy of the bd_info in
3059 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3061 - CONFIG_SYS_MAX_FLASH_BANKS:
3062 Max number of Flash memory banks
3064 - CONFIG_SYS_MAX_FLASH_SECT:
3065 Max number of sectors on a Flash chip
3067 - CONFIG_SYS_FLASH_ERASE_TOUT:
3068 Timeout for Flash erase operations (in ms)
3070 - CONFIG_SYS_FLASH_WRITE_TOUT:
3071 Timeout for Flash write operations (in ms)
3073 - CONFIG_SYS_FLASH_LOCK_TOUT
3074 Timeout for Flash set sector lock bit operation (in ms)
3076 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3077 Timeout for Flash clear lock bits operation (in ms)
3079 - CONFIG_SYS_FLASH_PROTECTION
3080 If defined, hardware flash sectors protection is used
3081 instead of U-Boot software protection.
3083 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3085 Enable TFTP transfers directly to flash memory;
3086 without this option such a download has to be
3087 performed in two steps: (1) download to RAM, and (2)
3088 copy from RAM to flash.
3090 The two-step approach is usually more reliable, since
3091 you can check if the download worked before you erase
3092 the flash, but in some situations (when system RAM is
3093 too limited to allow for a temporary copy of the
3094 downloaded image) this option may be very useful.
3096 - CONFIG_SYS_FLASH_CFI:
3097 Define if the flash driver uses extra elements in the
3098 common flash structure for storing flash geometry.
3100 - CONFIG_FLASH_CFI_DRIVER
3101 This option also enables the building of the cfi_flash driver
3102 in the drivers directory
3104 - CONFIG_FLASH_CFI_MTD
3105 This option enables the building of the cfi_mtd driver
3106 in the drivers directory. The driver exports CFI flash
3109 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3110 Use buffered writes to flash.
3112 - CONFIG_FLASH_SPANSION_S29WS_N
3113 s29ws-n MirrorBit flash has non-standard addresses for buffered
3116 - CONFIG_SYS_FLASH_QUIET_TEST
3117 If this option is defined, the common CFI flash doesn't
3118 print it's warning upon not recognized FLASH banks. This
3119 is useful, if some of the configured banks are only
3120 optionally available.
3122 - CONFIG_FLASH_SHOW_PROGRESS
3123 If defined (must be an integer), print out countdown
3124 digits and dots. Recommended value: 45 (9..1) for 80
3125 column displays, 15 (3..1) for 40 column displays.
3127 - CONFIG_SYS_RX_ETH_BUFFER:
3128 Defines the number of Ethernet receive buffers. On some
3129 Ethernet controllers it is recommended to set this value
3130 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3131 buffers can be full shortly after enabling the interface
3132 on high Ethernet traffic.
3133 Defaults to 4 if not defined.
3135 - CONFIG_ENV_MAX_ENTRIES
3137 Maximum number of entries in the hash table that is used
3138 internally to store the environment settings. The default
3139 setting is supposed to be generous and should work in most
3140 cases. This setting can be used to tune behaviour; see
3141 lib/hashtable.c for details.
3143 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3144 - CONFIG_ENV_FLAGS_LIST_STATIC
3145 Enable validation of the values given to enviroment variables when
3146 calling env set. Variables can be restricted to only decimal,
3147 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3148 the variables can also be restricted to IP address or MAC address.
3150 The format of the list is:
3151 type_attribute = [s|d|x|b|i|m]
3152 access_atribute = [a|r|o|c]
3153 attributes = type_attribute[access_atribute]
3154 entry = variable_name[:attributes]
3157 The type attributes are:
3158 s - String (default)
3161 b - Boolean ([1yYtT|0nNfF])
3165 The access attributes are:
3171 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3172 Define this to a list (string) to define the ".flags"
3173 envirnoment variable in the default or embedded environment.
3175 - CONFIG_ENV_FLAGS_LIST_STATIC
3176 Define this to a list (string) to define validation that
3177 should be done if an entry is not found in the ".flags"
3178 environment variable. To override a setting in the static
3179 list, simply add an entry for the same variable name to the
3182 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3183 If defined, don't allow the -f switch to env set override variable
3186 The following definitions that deal with the placement and management
3187 of environment data (variable area); in general, we support the
3188 following configurations:
3190 - CONFIG_BUILD_ENVCRC:
3192 Builds up envcrc with the target environment so that external utils
3193 may easily extract it and embed it in final U-Boot images.
3195 - CONFIG_ENV_IS_IN_FLASH:
3197 Define this if the environment is in flash memory.
3199 a) The environment occupies one whole flash sector, which is
3200 "embedded" in the text segment with the U-Boot code. This
3201 happens usually with "bottom boot sector" or "top boot
3202 sector" type flash chips, which have several smaller
3203 sectors at the start or the end. For instance, such a
3204 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3205 such a case you would place the environment in one of the
3206 4 kB sectors - with U-Boot code before and after it. With
3207 "top boot sector" type flash chips, you would put the
3208 environment in one of the last sectors, leaving a gap
3209 between U-Boot and the environment.
3211 - CONFIG_ENV_OFFSET:
3213 Offset of environment data (variable area) to the
3214 beginning of flash memory; for instance, with bottom boot
3215 type flash chips the second sector can be used: the offset
3216 for this sector is given here.
3218 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3222 This is just another way to specify the start address of
3223 the flash sector containing the environment (instead of
3226 - CONFIG_ENV_SECT_SIZE:
3228 Size of the sector containing the environment.
3231 b) Sometimes flash chips have few, equal sized, BIG sectors.
3232 In such a case you don't want to spend a whole sector for
3237 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3238 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3239 of this flash sector for the environment. This saves
3240 memory for the RAM copy of the environment.
3242 It may also save flash memory if you decide to use this
3243 when your environment is "embedded" within U-Boot code,
3244 since then the remainder of the flash sector could be used
3245 for U-Boot code. It should be pointed out that this is
3246 STRONGLY DISCOURAGED from a robustness point of view:
3247 updating the environment in flash makes it always
3248 necessary to erase the WHOLE sector. If something goes
3249 wrong before the contents has been restored from a copy in
3250 RAM, your target system will be dead.
3252 - CONFIG_ENV_ADDR_REDUND
3253 CONFIG_ENV_SIZE_REDUND
3255 These settings describe a second storage area used to hold
3256 a redundant copy of the environment data, so that there is
3257 a valid backup copy in case there is a power failure during
3258 a "saveenv" operation.
3260 BE CAREFUL! Any changes to the flash layout, and some changes to the
3261 source code will make it necessary to adapt <board>/u-boot.lds*
3265 - CONFIG_ENV_IS_IN_NVRAM:
3267 Define this if you have some non-volatile memory device
3268 (NVRAM, battery buffered SRAM) which you want to use for the
3274 These two #defines are used to determine the memory area you
3275 want to use for environment. It is assumed that this memory
3276 can just be read and written to, without any special
3279 BE CAREFUL! The first access to the environment happens quite early
3280 in U-Boot initalization (when we try to get the setting of for the
3281 console baudrate). You *MUST* have mapped your NVRAM area then, or
3284 Please note that even with NVRAM we still use a copy of the
3285 environment in RAM: we could work on NVRAM directly, but we want to
3286 keep settings there always unmodified except somebody uses "saveenv"
3287 to save the current settings.
3290 - CONFIG_ENV_IS_IN_EEPROM:
3292 Use this if you have an EEPROM or similar serial access
3293 device and a driver for it.
3295 - CONFIG_ENV_OFFSET:
3298 These two #defines specify the offset and size of the
3299 environment area within the total memory of your EEPROM.
3301 - CONFIG_SYS_I2C_EEPROM_ADDR:
3302 If defined, specified the chip address of the EEPROM device.
3303 The default address is zero.
3305 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3306 If defined, the number of bits used to address bytes in a
3307 single page in the EEPROM device. A 64 byte page, for example
3308 would require six bits.
3310 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3311 If defined, the number of milliseconds to delay between
3312 page writes. The default is zero milliseconds.
3314 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3315 The length in bytes of the EEPROM memory array address. Note
3316 that this is NOT the chip address length!
3318 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3319 EEPROM chips that implement "address overflow" are ones
3320 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3321 address and the extra bits end up in the "chip address" bit
3322 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3325 Note that we consider the length of the address field to
3326 still be one byte because the extra address bits are hidden
3327 in the chip address.
3329 - CONFIG_SYS_EEPROM_SIZE:
3330 The size in bytes of the EEPROM device.
3332 - CONFIG_ENV_EEPROM_IS_ON_I2C
3333 define this, if you have I2C and SPI activated, and your
3334 EEPROM, which holds the environment, is on the I2C bus.
3336 - CONFIG_I2C_ENV_EEPROM_BUS
3337 if you have an Environment on an EEPROM reached over
3338 I2C muxes, you can define here, how to reach this
3339 EEPROM. For example:
3341 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3343 EEPROM which holds the environment, is reached over
3344 a pca9547 i2c mux with address 0x70, channel 3.
3346 - CONFIG_ENV_IS_IN_DATAFLASH:
3348 Define this if you have a DataFlash memory device which you
3349 want to use for the environment.
3351 - CONFIG_ENV_OFFSET:
3355 These three #defines specify the offset and size of the
3356 environment area within the total memory of your DataFlash placed
3357 at the specified address.
3359 - CONFIG_ENV_IS_IN_REMOTE:
3361 Define this if you have a remote memory space which you
3362 want to use for the local device's environment.
3367 These two #defines specify the address and size of the
3368 environment area within the remote memory space. The
3369 local device can get the environment from remote memory
3370 space by SRIO or PCIE links.
3372 BE CAREFUL! For some special cases, the local device can not use
3373 "saveenv" command. For example, the local device will get the
3374 environment stored in a remote NOR flash by SRIO or PCIE link,
3375 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3377 - CONFIG_ENV_IS_IN_NAND:
3379 Define this if you have a NAND device which you want to use
3380 for the environment.
3382 - CONFIG_ENV_OFFSET:
3385 These two #defines specify the offset and size of the environment
3386 area within the first NAND device. CONFIG_ENV_OFFSET must be
3387 aligned to an erase block boundary.
3389 - CONFIG_ENV_OFFSET_REDUND (optional):
3391 This setting describes a second storage area of CONFIG_ENV_SIZE
3392 size used to hold a redundant copy of the environment data, so
3393 that there is a valid backup copy in case there is a power failure
3394 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3395 aligned to an erase block boundary.
3397 - CONFIG_ENV_RANGE (optional):
3399 Specifies the length of the region in which the environment
3400 can be written. This should be a multiple of the NAND device's
3401 block size. Specifying a range with more erase blocks than
3402 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3403 the range to be avoided.
3405 - CONFIG_ENV_OFFSET_OOB (optional):
3407 Enables support for dynamically retrieving the offset of the
3408 environment from block zero's out-of-band data. The
3409 "nand env.oob" command can be used to record this offset.
3410 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3411 using CONFIG_ENV_OFFSET_OOB.
3413 - CONFIG_NAND_ENV_DST
3415 Defines address in RAM to which the nand_spl code should copy the
3416 environment. If redundant environment is used, it will be copied to
3417 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3419 - CONFIG_SYS_SPI_INIT_OFFSET
3421 Defines offset to the initial SPI buffer area in DPRAM. The
3422 area is used at an early stage (ROM part) if the environment
3423 is configured to reside in the SPI EEPROM: We need a 520 byte
3424 scratch DPRAM area. It is used between the two initialization
3425 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3426 to be a good choice since it makes it far enough from the
3427 start of the data area as well as from the stack pointer.
3429 Please note that the environment is read-only until the monitor
3430 has been relocated to RAM and a RAM copy of the environment has been
3431 created; also, when using EEPROM you will have to use getenv_f()
3432 until then to read environment variables.
3434 The environment is protected by a CRC32 checksum. Before the monitor
3435 is relocated into RAM, as a result of a bad CRC you will be working
3436 with the compiled-in default environment - *silently*!!! [This is
3437 necessary, because the first environment variable we need is the
3438 "baudrate" setting for the console - if we have a bad CRC, we don't
3439 have any device yet where we could complain.]
3441 Note: once the monitor has been relocated, then it will complain if
3442 the default environment is used; a new CRC is computed as soon as you
3443 use the "saveenv" command to store a valid environment.
3445 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3446 Echo the inverted Ethernet link state to the fault LED.
3448 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3449 also needs to be defined.
3451 - CONFIG_SYS_FAULT_MII_ADDR:
3452 MII address of the PHY to check for the Ethernet link state.
3454 - CONFIG_NS16550_MIN_FUNCTIONS:
3455 Define this if you desire to only have use of the NS16550_init
3456 and NS16550_putc functions for the serial driver located at
3457 drivers/serial/ns16550.c. This option is useful for saving
3458 space for already greatly restricted images, including but not
3459 limited to NAND_SPL configurations.
3461 - CONFIG_DISPLAY_BOARDINFO
3462 Display information about the board that U-Boot is running on
3463 when U-Boot starts up. The board function checkboard() is called
3466 - CONFIG_DISPLAY_BOARDINFO_LATE
3467 Similar to the previous option, but display this information
3468 later, once stdio is running and output goes to the LCD, if
3471 Low Level (hardware related) configuration options:
3472 ---------------------------------------------------
3474 - CONFIG_SYS_CACHELINE_SIZE:
3475 Cache Line Size of the CPU.
3477 - CONFIG_SYS_DEFAULT_IMMR:
3478 Default address of the IMMR after system reset.
3480 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3481 and RPXsuper) to be able to adjust the position of
3482 the IMMR register after a reset.
3484 - CONFIG_SYS_CCSRBAR_DEFAULT:
3485 Default (power-on reset) physical address of CCSR on Freescale
3488 - CONFIG_SYS_CCSRBAR:
3489 Virtual address of CCSR. On a 32-bit build, this is typically
3490 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3492 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3493 for cross-platform code that uses that macro instead.
3495 - CONFIG_SYS_CCSRBAR_PHYS:
3496 Physical address of CCSR. CCSR can be relocated to a new
3497 physical address, if desired. In this case, this macro should
3498 be set to that address. Otherwise, it should be set to the
3499 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3500 is typically relocated on 36-bit builds. It is recommended
3501 that this macro be defined via the _HIGH and _LOW macros:
3503 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3504 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3506 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3507 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3508 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3509 used in assembly code, so it must not contain typecasts or
3510 integer size suffixes (e.g. "ULL").
3512 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3513 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3514 used in assembly code, so it must not contain typecasts or
3515 integer size suffixes (e.g. "ULL").
3517 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3518 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3519 forced to a value that ensures that CCSR is not relocated.
3521 - Floppy Disk Support:
3522 CONFIG_SYS_FDC_DRIVE_NUMBER
3524 the default drive number (default value 0)
3526 CONFIG_SYS_ISA_IO_STRIDE
3528 defines the spacing between FDC chipset registers
3531 CONFIG_SYS_ISA_IO_OFFSET
3533 defines the offset of register from address. It
3534 depends on which part of the data bus is connected to
3535 the FDC chipset. (default value 0)
3537 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3538 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3541 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3542 fdc_hw_init() is called at the beginning of the FDC
3543 setup. fdc_hw_init() must be provided by the board
3544 source code. It is used to make hardware dependant
3548 Most IDE controllers were designed to be connected with PCI
3549 interface. Only few of them were designed for AHB interface.
3550 When software is doing ATA command and data transfer to
3551 IDE devices through IDE-AHB controller, some additional
3552 registers accessing to these kind of IDE-AHB controller
3555 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3556 DO NOT CHANGE unless you know exactly what you're
3557 doing! (11-4) [MPC8xx/82xx systems only]
3559 - CONFIG_SYS_INIT_RAM_ADDR:
3561 Start address of memory area that can be used for
3562 initial data and stack; please note that this must be
3563 writable memory that is working WITHOUT special
3564 initialization, i. e. you CANNOT use normal RAM which
3565 will become available only after programming the
3566 memory controller and running certain initialization
3569 U-Boot uses the following memory types:
3570 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3571 - MPC824X: data cache
3572 - PPC4xx: data cache
3574 - CONFIG_SYS_GBL_DATA_OFFSET:
3576 Offset of the initial data structure in the memory
3577 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3578 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3579 data is located at the end of the available space
3580 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3581 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3582 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3583 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3586 On the MPC824X (or other systems that use the data
3587 cache for initial memory) the address chosen for
3588 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3589 point to an otherwise UNUSED address space between
3590 the top of RAM and the start of the PCI space.
3592 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3594 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3596 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3598 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3600 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3602 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3604 - CONFIG_SYS_OR_TIMING_SDRAM:
3607 - CONFIG_SYS_MAMR_PTA:
3608 periodic timer for refresh
3610 - CONFIG_SYS_DER: Debug Event Register (37-47)
3612 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3613 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3614 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3615 CONFIG_SYS_BR1_PRELIM:
3616 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3618 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3619 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3620 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3621 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3623 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3624 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3625 Machine Mode Register and Memory Periodic Timer
3626 Prescaler definitions (SDRAM timing)
3628 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3629 enable I2C microcode relocation patch (MPC8xx);
3630 define relocation offset in DPRAM [DSP2]
3632 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3633 enable SMC microcode relocation patch (MPC8xx);
3634 define relocation offset in DPRAM [SMC1]
3636 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3637 enable SPI microcode relocation patch (MPC8xx);
3638 define relocation offset in DPRAM [SCC4]
3640 - CONFIG_SYS_USE_OSCCLK:
3641 Use OSCM clock mode on MBX8xx board. Be careful,
3642 wrong setting might damage your board. Read
3643 doc/README.MBX before setting this variable!
3645 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3646 Offset of the bootmode word in DPRAM used by post
3647 (Power On Self Tests). This definition overrides
3648 #define'd default value in commproc.h resp.
3651 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3652 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3653 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3654 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3655 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3656 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3657 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3658 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3659 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3661 - CONFIG_PCI_DISABLE_PCIE:
3662 Disable PCI-Express on systems where it is supported but not
3665 - CONFIG_PCI_ENUM_ONLY
3666 Only scan through and get the devices on the busses.
3667 Don't do any setup work, presumably because someone or
3668 something has already done it, and we don't need to do it
3669 a second time. Useful for platforms that are pre-booted
3670 by coreboot or similar.
3673 Chip has SRIO or not
3676 Board has SRIO 1 port available
3679 Board has SRIO 2 port available
3681 - CONFIG_SYS_SRIOn_MEM_VIRT:
3682 Virtual Address of SRIO port 'n' memory region
3684 - CONFIG_SYS_SRIOn_MEM_PHYS:
3685 Physical Address of SRIO port 'n' memory region
3687 - CONFIG_SYS_SRIOn_MEM_SIZE:
3688 Size of SRIO port 'n' memory region
3690 - CONFIG_SYS_NDFC_16
3691 Defined to tell the NDFC that the NAND chip is using a
3694 - CONFIG_SYS_NDFC_EBC0_CFG
3695 Sets the EBC0_CFG register for the NDFC. If not defined
3696 a default value will be used.
3699 Get DDR timing information from an I2C EEPROM. Common
3700 with pluggable memory modules such as SODIMMs
3703 I2C address of the SPD EEPROM
3705 - CONFIG_SYS_SPD_BUS_NUM
3706 If SPD EEPROM is on an I2C bus other than the first
3707 one, specify here. Note that the value must resolve
3708 to something your driver can deal with.
3710 - CONFIG_SYS_DDR_RAW_TIMING
3711 Get DDR timing information from other than SPD. Common with
3712 soldered DDR chips onboard without SPD. DDR raw timing
3713 parameters are extracted from datasheet and hard-coded into
3714 header files or board specific files.
3716 - CONFIG_FSL_DDR_INTERACTIVE
3717 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3719 - CONFIG_SYS_83XX_DDR_USES_CS0
3720 Only for 83xx systems. If specified, then DDR should
3721 be configured using CS0 and CS1 instead of CS2 and CS3.
3723 - CONFIG_ETHER_ON_FEC[12]
3724 Define to enable FEC[12] on a 8xx series processor.
3726 - CONFIG_FEC[12]_PHY
3727 Define to the hardcoded PHY address which corresponds
3728 to the given FEC; i. e.
3729 #define CONFIG_FEC1_PHY 4
3730 means that the PHY with address 4 is connected to FEC1
3732 When set to -1, means to probe for first available.
3734 - CONFIG_FEC[12]_PHY_NORXERR
3735 The PHY does not have a RXERR line (RMII only).
3736 (so program the FEC to ignore it).
3739 Enable RMII mode for all FECs.
3740 Note that this is a global option, we can't
3741 have one FEC in standard MII mode and another in RMII mode.
3743 - CONFIG_CRC32_VERIFY
3744 Add a verify option to the crc32 command.
3747 => crc32 -v <address> <count> <crc32>
3749 Where address/count indicate a memory area
3750 and crc32 is the correct crc32 which the
3754 Add the "loopw" memory command. This only takes effect if
3755 the memory commands are activated globally (CONFIG_CMD_MEM).
3758 Add the "mdc" and "mwc" memory commands. These are cyclic
3763 This command will print 4 bytes (10,11,12,13) each 500 ms.
3765 => mwc.l 100 12345678 10
3766 This command will write 12345678 to address 100 all 10 ms.
3768 This only takes effect if the memory commands are activated
3769 globally (CONFIG_CMD_MEM).
3771 - CONFIG_SKIP_LOWLEVEL_INIT
3772 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3773 low level initializations (like setting up the memory
3774 controller) are omitted and/or U-Boot does not
3775 relocate itself into RAM.
3777 Normally this variable MUST NOT be defined. The only
3778 exception is when U-Boot is loaded (to RAM) by some
3779 other boot loader or by a debugger which performs
3780 these initializations itself.
3783 Modifies the behaviour of start.S when compiling a loader
3784 that is executed before the actual U-Boot. E.g. when
3785 compiling a NAND SPL.
3787 - CONFIG_USE_ARCH_MEMCPY
3788 CONFIG_USE_ARCH_MEMSET
3789 If these options are used a optimized version of memcpy/memset will
3790 be used if available. These functions may be faster under some
3791 conditions but may increase the binary size.
3793 - CONFIG_X86_NO_RESET_VECTOR
3794 If defined, the x86 reset vector code is excluded. You will need
3795 to do this when U-Boot is running from Coreboot.
3797 - CONFIG_X86_NO_REAL_MODE
3798 If defined, x86 real mode code is omitted. This assumes a
3799 32-bit environment where such code is not needed. You will
3800 need to do this when U-Boot is running from Coreboot.
3803 Freescale QE/FMAN Firmware Support:
3804 -----------------------------------
3806 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3807 loading of "firmware", which is encoded in the QE firmware binary format.
3808 This firmware often needs to be loaded during U-Boot booting, so macros
3809 are used to identify the storage device (NOR flash, SPI, etc) and the address
3812 - CONFIG_SYS_QE_FMAN_FW_ADDR
3813 The address in the storage device where the firmware is located. The
3814 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3817 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3818 The maximum possible size of the firmware. The firmware binary format
3819 has a field that specifies the actual size of the firmware, but it
3820 might not be possible to read any part of the firmware unless some
3821 local storage is allocated to hold the entire firmware first.
3823 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3824 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3825 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3826 virtual address in NOR flash.
3828 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3829 Specifies that QE/FMAN firmware is located in NAND flash.
3830 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3832 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3833 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3834 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3836 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3837 Specifies that QE/FMAN firmware is located on the primary SPI
3838 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3840 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3841 Specifies that QE/FMAN firmware is located in the remote (master)
3842 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3843 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3844 window->master inbound window->master LAW->the ucode address in
3845 master's memory space.
3847 Building the Software:
3848 ======================
3850 Building U-Boot has been tested in several native build environments
3851 and in many different cross environments. Of course we cannot support
3852 all possibly existing versions of cross development tools in all
3853 (potentially obsolete) versions. In case of tool chain problems we
3854 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3855 which is extensively used to build and test U-Boot.
3857 If you are not using a native environment, it is assumed that you
3858 have GNU cross compiling tools available in your path. In this case,
3859 you must set the environment variable CROSS_COMPILE in your shell.
3860 Note that no changes to the Makefile or any other source files are
3861 necessary. For example using the ELDK on a 4xx CPU, please enter:
3863 $ CROSS_COMPILE=ppc_4xx-
3864 $ export CROSS_COMPILE
3866 Note: If you wish to generate Windows versions of the utilities in
3867 the tools directory you can use the MinGW toolchain
3868 (http://www.mingw.org). Set your HOST tools to the MinGW
3869 toolchain and execute 'make tools'. For example:
3871 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3873 Binaries such as tools/mkimage.exe will be created which can
3874 be executed on computers running Windows.
3876 U-Boot is intended to be simple to build. After installing the
3877 sources you must configure U-Boot for one specific board type. This
3882 where "NAME_config" is the name of one of the existing configu-
3883 rations; see boards.cfg for supported names.
3885 Note: for some board special configuration names may exist; check if
3886 additional information is available from the board vendor; for
3887 instance, the TQM823L systems are available without (standard)
3888 or with LCD support. You can select such additional "features"
3889 when choosing the configuration, i. e.
3892 - will configure for a plain TQM823L, i. e. no LCD support
3894 make TQM823L_LCD_config
3895 - will configure for a TQM823L with U-Boot console on LCD
3900 Finally, type "make all", and you should get some working U-Boot
3901 images ready for download to / installation on your system:
3903 - "u-boot.bin" is a raw binary image
3904 - "u-boot" is an image in ELF binary format
3905 - "u-boot.srec" is in Motorola S-Record format
3907 By default the build is performed locally and the objects are saved
3908 in the source directory. One of the two methods can be used to change
3909 this behavior and build U-Boot to some external directory:
3911 1. Add O= to the make command line invocations:
3913 make O=/tmp/build distclean
3914 make O=/tmp/build NAME_config
3915 make O=/tmp/build all
3917 2. Set environment variable BUILD_DIR to point to the desired location:
3919 export BUILD_DIR=/tmp/build
3924 Note that the command line "O=" setting overrides the BUILD_DIR environment
3928 Please be aware that the Makefiles assume you are using GNU make, so
3929 for instance on NetBSD you might need to use "gmake" instead of
3933 If the system board that you have is not listed, then you will need
3934 to port U-Boot to your hardware platform. To do this, follow these
3937 1. Add a new configuration option for your board to the toplevel
3938 "boards.cfg" file, using the existing entries as examples.
3939 Follow the instructions there to keep the boards in order.
3940 2. Create a new directory to hold your board specific code. Add any
3941 files you need. In your board directory, you will need at least
3942 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3943 3. Create a new configuration file "include/configs/<board>.h" for
3945 3. If you're porting U-Boot to a new CPU, then also create a new
3946 directory to hold your CPU specific code. Add any files you need.
3947 4. Run "make <board>_config" with your new name.
3948 5. Type "make", and you should get a working "u-boot.srec" file
3949 to be installed on your target system.
3950 6. Debug and solve any problems that might arise.
3951 [Of course, this last step is much harder than it sounds.]
3954 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3955 ==============================================================
3957 If you have modified U-Boot sources (for instance added a new board
3958 or support for new devices, a new CPU, etc.) you are expected to
3959 provide feedback to the other developers. The feedback normally takes
3960 the form of a "patch", i. e. a context diff against a certain (latest
3961 official or latest in the git repository) version of U-Boot sources.
3963 But before you submit such a patch, please verify that your modifi-
3964 cation did not break existing code. At least make sure that *ALL* of
3965 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3966 just run the "MAKEALL" script, which will configure and build U-Boot
3967 for ALL supported system. Be warned, this will take a while. You can
3968 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3969 environment variable to the script, i. e. to use the ELDK cross tools
3972 CROSS_COMPILE=ppc_8xx- MAKEALL
3974 or to build on a native PowerPC system you can type
3976 CROSS_COMPILE=' ' MAKEALL
3978 When using the MAKEALL script, the default behaviour is to build
3979 U-Boot in the source directory. This location can be changed by
3980 setting the BUILD_DIR environment variable. Also, for each target
3981 built, the MAKEALL script saves two log files (<target>.ERR and
3982 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3983 location can be changed by setting the MAKEALL_LOGDIR environment
3984 variable. For example:
3986 export BUILD_DIR=/tmp/build
3987 export MAKEALL_LOGDIR=/tmp/log
3988 CROSS_COMPILE=ppc_8xx- MAKEALL
3990 With the above settings build objects are saved in the /tmp/build,
3991 log files are saved in the /tmp/log and the source tree remains clean
3992 during the whole build process.
3995 See also "U-Boot Porting Guide" below.
3998 Monitor Commands - Overview:
3999 ============================
4001 go - start application at address 'addr'
4002 run - run commands in an environment variable
4003 bootm - boot application image from memory
4004 bootp - boot image via network using BootP/TFTP protocol
4005 bootz - boot zImage from memory
4006 tftpboot- boot image via network using TFTP protocol
4007 and env variables "ipaddr" and "serverip"
4008 (and eventually "gatewayip")
4009 tftpput - upload a file via network using TFTP protocol
4010 rarpboot- boot image via network using RARP/TFTP protocol
4011 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4012 loads - load S-Record file over serial line
4013 loadb - load binary file over serial line (kermit mode)
4015 mm - memory modify (auto-incrementing)
4016 nm - memory modify (constant address)
4017 mw - memory write (fill)
4019 cmp - memory compare
4020 crc32 - checksum calculation
4021 i2c - I2C sub-system
4022 sspi - SPI utility commands
4023 base - print or set address offset
4024 printenv- print environment variables
4025 setenv - set environment variables
4026 saveenv - save environment variables to persistent storage
4027 protect - enable or disable FLASH write protection
4028 erase - erase FLASH memory
4029 flinfo - print FLASH memory information
4030 nand - NAND memory operations (see doc/README.nand)
4031 bdinfo - print Board Info structure
4032 iminfo - print header information for application image
4033 coninfo - print console devices and informations
4034 ide - IDE sub-system
4035 loop - infinite loop on address range
4036 loopw - infinite write loop on address range
4037 mtest - simple RAM test
4038 icache - enable or disable instruction cache
4039 dcache - enable or disable data cache
4040 reset - Perform RESET of the CPU
4041 echo - echo args to console
4042 version - print monitor version
4043 help - print online help
4044 ? - alias for 'help'
4047 Monitor Commands - Detailed Description:
4048 ========================================
4052 For now: just type "help <command>".
4055 Environment Variables:
4056 ======================
4058 U-Boot supports user configuration using Environment Variables which
4059 can be made persistent by saving to Flash memory.
4061 Environment Variables are set using "setenv", printed using
4062 "printenv", and saved to Flash using "saveenv". Using "setenv"
4063 without a value can be used to delete a variable from the
4064 environment. As long as you don't save the environment you are
4065 working with an in-memory copy. In case the Flash area containing the
4066 environment is erased by accident, a default environment is provided.
4068 Some configuration options can be set using Environment Variables.
4070 List of environment variables (most likely not complete):
4072 baudrate - see CONFIG_BAUDRATE
4074 bootdelay - see CONFIG_BOOTDELAY
4076 bootcmd - see CONFIG_BOOTCOMMAND
4078 bootargs - Boot arguments when booting an RTOS image
4080 bootfile - Name of the image to load with TFTP
4082 bootm_low - Memory range available for image processing in the bootm
4083 command can be restricted. This variable is given as
4084 a hexadecimal number and defines lowest address allowed
4085 for use by the bootm command. See also "bootm_size"
4086 environment variable. Address defined by "bootm_low" is
4087 also the base of the initial memory mapping for the Linux
4088 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4091 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4092 This variable is given as a hexadecimal number and it
4093 defines the size of the memory region starting at base
4094 address bootm_low that is accessible by the Linux kernel
4095 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4096 as the default value if it is defined, and bootm_size is
4099 bootm_size - Memory range available for image processing in the bootm
4100 command can be restricted. This variable is given as
4101 a hexadecimal number and defines the size of the region
4102 allowed for use by the bootm command. See also "bootm_low"
4103 environment variable.
4105 updatefile - Location of the software update file on a TFTP server, used
4106 by the automatic software update feature. Please refer to
4107 documentation in doc/README.update for more details.
4109 autoload - if set to "no" (any string beginning with 'n'),
4110 "bootp" will just load perform a lookup of the
4111 configuration from the BOOTP server, but not try to
4112 load any image using TFTP
4114 autostart - if set to "yes", an image loaded using the "bootp",
4115 "rarpboot", "tftpboot" or "diskboot" commands will
4116 be automatically started (by internally calling
4119 If set to "no", a standalone image passed to the
4120 "bootm" command will be copied to the load address
4121 (and eventually uncompressed), but NOT be started.
4122 This can be used to load and uncompress arbitrary
4125 fdt_high - if set this restricts the maximum address that the
4126 flattened device tree will be copied into upon boot.
4127 For example, if you have a system with 1 GB memory
4128 at physical address 0x10000000, while Linux kernel
4129 only recognizes the first 704 MB as low memory, you
4130 may need to set fdt_high as 0x3C000000 to have the
4131 device tree blob be copied to the maximum address
4132 of the 704 MB low memory, so that Linux kernel can
4133 access it during the boot procedure.
4135 If this is set to the special value 0xFFFFFFFF then
4136 the fdt will not be copied at all on boot. For this
4137 to work it must reside in writable memory, have
4138 sufficient padding on the end of it for u-boot to
4139 add the information it needs into it, and the memory
4140 must be accessible by the kernel.
4142 fdtcontroladdr- if set this is the address of the control flattened
4143 device tree used by U-Boot when CONFIG_OF_CONTROL is
4146 i2cfast - (PPC405GP|PPC405EP only)
4147 if set to 'y' configures Linux I2C driver for fast
4148 mode (400kHZ). This environment variable is used in
4149 initialization code. So, for changes to be effective
4150 it must be saved and board must be reset.
4152 initrd_high - restrict positioning of initrd images:
4153 If this variable is not set, initrd images will be
4154 copied to the highest possible address in RAM; this
4155 is usually what you want since it allows for
4156 maximum initrd size. If for some reason you want to
4157 make sure that the initrd image is loaded below the
4158 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4159 variable to a value of "no" or "off" or "0".
4160 Alternatively, you can set it to a maximum upper
4161 address to use (U-Boot will still check that it
4162 does not overwrite the U-Boot stack and data).
4164 For instance, when you have a system with 16 MB
4165 RAM, and want to reserve 4 MB from use by Linux,
4166 you can do this by adding "mem=12M" to the value of
4167 the "bootargs" variable. However, now you must make
4168 sure that the initrd image is placed in the first
4169 12 MB as well - this can be done with
4171 setenv initrd_high 00c00000
4173 If you set initrd_high to 0xFFFFFFFF, this is an
4174 indication to U-Boot that all addresses are legal
4175 for the Linux kernel, including addresses in flash
4176 memory. In this case U-Boot will NOT COPY the
4177 ramdisk at all. This may be useful to reduce the
4178 boot time on your system, but requires that this
4179 feature is supported by your Linux kernel.
4181 ipaddr - IP address; needed for tftpboot command
4183 loadaddr - Default load address for commands like "bootp",
4184 "rarpboot", "tftpboot", "loadb" or "diskboot"
4186 loads_echo - see CONFIG_LOADS_ECHO
4188 serverip - TFTP server IP address; needed for tftpboot command
4190 bootretry - see CONFIG_BOOT_RETRY_TIME
4192 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4194 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4196 ethprime - controls which interface is used first.
4198 ethact - controls which interface is currently active.
4199 For example you can do the following
4201 => setenv ethact FEC
4202 => ping 192.168.0.1 # traffic sent on FEC
4203 => setenv ethact SCC
4204 => ping 10.0.0.1 # traffic sent on SCC
4206 ethrotate - When set to "no" U-Boot does not go through all
4207 available network interfaces.
4208 It just stays at the currently selected interface.
4210 netretry - When set to "no" each network operation will
4211 either succeed or fail without retrying.
4212 When set to "once" the network operation will
4213 fail when all the available network interfaces
4214 are tried once without success.
4215 Useful on scripts which control the retry operation
4218 npe_ucode - set load address for the NPE microcode
4220 tftpsrcport - If this is set, the value is used for TFTP's
4223 tftpdstport - If this is set, the value is used for TFTP's UDP
4224 destination port instead of the Well Know Port 69.
4226 tftpblocksize - Block size to use for TFTP transfers; if not set,
4227 we use the TFTP server's default block size
4229 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4230 seconds, minimum value is 1000 = 1 second). Defines
4231 when a packet is considered to be lost so it has to
4232 be retransmitted. The default is 5000 = 5 seconds.
4233 Lowering this value may make downloads succeed
4234 faster in networks with high packet loss rates or
4235 with unreliable TFTP servers.
4237 vlan - When set to a value < 4095 the traffic over
4238 Ethernet is encapsulated/received over 802.1q
4241 The following image location variables contain the location of images
4242 used in booting. The "Image" column gives the role of the image and is
4243 not an environment variable name. The other columns are environment
4244 variable names. "File Name" gives the name of the file on a TFTP
4245 server, "RAM Address" gives the location in RAM the image will be
4246 loaded to, and "Flash Location" gives the image's address in NOR
4247 flash or offset in NAND flash.
4249 *Note* - these variables don't have to be defined for all boards, some
4250 boards currenlty use other variables for these purposes, and some
4251 boards use these variables for other purposes.
4253 Image File Name RAM Address Flash Location
4254 ----- --------- ----------- --------------
4255 u-boot u-boot u-boot_addr_r u-boot_addr
4256 Linux kernel bootfile kernel_addr_r kernel_addr
4257 device tree blob fdtfile fdt_addr_r fdt_addr
4258 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4260 The following environment variables may be used and automatically
4261 updated by the network boot commands ("bootp" and "rarpboot"),
4262 depending the information provided by your boot server:
4264 bootfile - see above
4265 dnsip - IP address of your Domain Name Server
4266 dnsip2 - IP address of your secondary Domain Name Server
4267 gatewayip - IP address of the Gateway (Router) to use
4268 hostname - Target hostname
4270 netmask - Subnet Mask
4271 rootpath - Pathname of the root filesystem on the NFS server
4272 serverip - see above
4275 There are two special Environment Variables:
4277 serial# - contains hardware identification information such
4278 as type string and/or serial number
4279 ethaddr - Ethernet address
4281 These variables can be set only once (usually during manufacturing of
4282 the board). U-Boot refuses to delete or overwrite these variables
4283 once they have been set once.
4286 Further special Environment Variables:
4288 ver - Contains the U-Boot version string as printed
4289 with the "version" command. This variable is
4290 readonly (see CONFIG_VERSION_VARIABLE).
4293 Please note that changes to some configuration parameters may take
4294 only effect after the next boot (yes, that's just like Windoze :-).
4297 Callback functions for environment variables:
4298 ---------------------------------------------
4300 For some environment variables, the behavior of u-boot needs to change
4301 when their values are changed. This functionailty allows functions to
4302 be associated with arbitrary variables. On creation, overwrite, or
4303 deletion, the callback will provide the opportunity for some side
4304 effect to happen or for the change to be rejected.
4306 The callbacks are named and associated with a function using the
4307 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4309 These callbacks are associated with variables in one of two ways. The
4310 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4311 in the board configuration to a string that defines a list of
4312 associations. The list must be in the following format:
4314 entry = variable_name[:callback_name]
4317 If the callback name is not specified, then the callback is deleted.
4318 Spaces are also allowed anywhere in the list.
4320 Callbacks can also be associated by defining the ".callbacks" variable
4321 with the same list format above. Any association in ".callbacks" will
4322 override any association in the static list. You can define
4323 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4324 ".callbacks" envirnoment variable in the default or embedded environment.
4327 Command Line Parsing:
4328 =====================
4330 There are two different command line parsers available with U-Boot:
4331 the old "simple" one, and the much more powerful "hush" shell:
4333 Old, simple command line parser:
4334 --------------------------------
4336 - supports environment variables (through setenv / saveenv commands)
4337 - several commands on one line, separated by ';'
4338 - variable substitution using "... ${name} ..." syntax
4339 - special characters ('$', ';') can be escaped by prefixing with '\',
4341 setenv bootcmd bootm \${address}
4342 - You can also escape text by enclosing in single apostrophes, for example:
4343 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4348 - similar to Bourne shell, with control structures like
4349 if...then...else...fi, for...do...done; while...do...done,
4350 until...do...done, ...
4351 - supports environment ("global") variables (through setenv / saveenv
4352 commands) and local shell variables (through standard shell syntax
4353 "name=value"); only environment variables can be used with "run"
4359 (1) If a command line (or an environment variable executed by a "run"
4360 command) contains several commands separated by semicolon, and
4361 one of these commands fails, then the remaining commands will be
4364 (2) If you execute several variables with one call to run (i. e.
4365 calling run with a list of variables as arguments), any failing
4366 command will cause "run" to terminate, i. e. the remaining
4367 variables are not executed.
4369 Note for Redundant Ethernet Interfaces:
4370 =======================================
4372 Some boards come with redundant Ethernet interfaces; U-Boot supports
4373 such configurations and is capable of automatic selection of a
4374 "working" interface when needed. MAC assignment works as follows:
4376 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4377 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4378 "eth1addr" (=>eth1), "eth2addr", ...
4380 If the network interface stores some valid MAC address (for instance
4381 in SROM), this is used as default address if there is NO correspon-
4382 ding setting in the environment; if the corresponding environment
4383 variable is set, this overrides the settings in the card; that means:
4385 o If the SROM has a valid MAC address, and there is no address in the
4386 environment, the SROM's address is used.
4388 o If there is no valid address in the SROM, and a definition in the
4389 environment exists, then the value from the environment variable is
4392 o If both the SROM and the environment contain a MAC address, and
4393 both addresses are the same, this MAC address is used.
4395 o If both the SROM and the environment contain a MAC address, and the
4396 addresses differ, the value from the environment is used and a
4399 o If neither SROM nor the environment contain a MAC address, an error
4402 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4403 will be programmed into hardware as part of the initialization process. This
4404 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4405 The naming convention is as follows:
4406 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4411 U-Boot is capable of booting (and performing other auxiliary operations on)
4412 images in two formats:
4414 New uImage format (FIT)
4415 -----------------------
4417 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4418 to Flattened Device Tree). It allows the use of images with multiple
4419 components (several kernels, ramdisks, etc.), with contents protected by
4420 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4426 Old image format is based on binary files which can be basically anything,
4427 preceded by a special header; see the definitions in include/image.h for
4428 details; basically, the header defines the following image properties:
4430 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4431 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4432 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4433 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4435 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4436 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4437 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4438 * Compression Type (uncompressed, gzip, bzip2)
4444 The header is marked by a special Magic Number, and both the header
4445 and the data portions of the image are secured against corruption by
4452 Although U-Boot should support any OS or standalone application
4453 easily, the main focus has always been on Linux during the design of
4456 U-Boot includes many features that so far have been part of some
4457 special "boot loader" code within the Linux kernel. Also, any
4458 "initrd" images to be used are no longer part of one big Linux image;
4459 instead, kernel and "initrd" are separate images. This implementation
4460 serves several purposes:
4462 - the same features can be used for other OS or standalone
4463 applications (for instance: using compressed images to reduce the
4464 Flash memory footprint)
4466 - it becomes much easier to port new Linux kernel versions because
4467 lots of low-level, hardware dependent stuff are done by U-Boot
4469 - the same Linux kernel image can now be used with different "initrd"
4470 images; of course this also means that different kernel images can
4471 be run with the same "initrd". This makes testing easier (you don't
4472 have to build a new "zImage.initrd" Linux image when you just
4473 change a file in your "initrd"). Also, a field-upgrade of the
4474 software is easier now.
4480 Porting Linux to U-Boot based systems:
4481 ---------------------------------------
4483 U-Boot cannot save you from doing all the necessary modifications to
4484 configure the Linux device drivers for use with your target hardware
4485 (no, we don't intend to provide a full virtual machine interface to
4488 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4490 Just make sure your machine specific header file (for instance
4491 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4492 Information structure as we define in include/asm-<arch>/u-boot.h,
4493 and make sure that your definition of IMAP_ADDR uses the same value
4494 as your U-Boot configuration in CONFIG_SYS_IMMR.
4497 Configuring the Linux kernel:
4498 -----------------------------
4500 No specific requirements for U-Boot. Make sure you have some root
4501 device (initial ramdisk, NFS) for your target system.
4504 Building a Linux Image:
4505 -----------------------
4507 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4508 not used. If you use recent kernel source, a new build target
4509 "uImage" will exist which automatically builds an image usable by
4510 U-Boot. Most older kernels also have support for a "pImage" target,
4511 which was introduced for our predecessor project PPCBoot and uses a
4512 100% compatible format.
4521 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4522 encapsulate a compressed Linux kernel image with header information,
4523 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4525 * build a standard "vmlinux" kernel image (in ELF binary format):
4527 * convert the kernel into a raw binary image:
4529 ${CROSS_COMPILE}-objcopy -O binary \
4530 -R .note -R .comment \
4531 -S vmlinux linux.bin
4533 * compress the binary image:
4537 * package compressed binary image for U-Boot:
4539 mkimage -A ppc -O linux -T kernel -C gzip \
4540 -a 0 -e 0 -n "Linux Kernel Image" \
4541 -d linux.bin.gz uImage
4544 The "mkimage" tool can also be used to create ramdisk images for use
4545 with U-Boot, either separated from the Linux kernel image, or
4546 combined into one file. "mkimage" encapsulates the images with a 64
4547 byte header containing information about target architecture,
4548 operating system, image type, compression method, entry points, time
4549 stamp, CRC32 checksums, etc.
4551 "mkimage" can be called in two ways: to verify existing images and
4552 print the header information, or to build new images.
4554 In the first form (with "-l" option) mkimage lists the information
4555 contained in the header of an existing U-Boot image; this includes
4556 checksum verification:
4558 tools/mkimage -l image
4559 -l ==> list image header information
4561 The second form (with "-d" option) is used to build a U-Boot image
4562 from a "data file" which is used as image payload:
4564 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4565 -n name -d data_file image
4566 -A ==> set architecture to 'arch'
4567 -O ==> set operating system to 'os'
4568 -T ==> set image type to 'type'
4569 -C ==> set compression type 'comp'
4570 -a ==> set load address to 'addr' (hex)
4571 -e ==> set entry point to 'ep' (hex)
4572 -n ==> set image name to 'name'
4573 -d ==> use image data from 'datafile'
4575 Right now, all Linux kernels for PowerPC systems use the same load
4576 address (0x00000000), but the entry point address depends on the
4579 - 2.2.x kernels have the entry point at 0x0000000C,
4580 - 2.3.x and later kernels have the entry point at 0x00000000.
4582 So a typical call to build a U-Boot image would read:
4584 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4585 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4586 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4587 > examples/uImage.TQM850L
4588 Image Name: 2.4.4 kernel for TQM850L
4589 Created: Wed Jul 19 02:34:59 2000
4590 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4591 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4592 Load Address: 0x00000000
4593 Entry Point: 0x00000000
4595 To verify the contents of the image (or check for corruption):
4597 -> tools/mkimage -l examples/uImage.TQM850L
4598 Image Name: 2.4.4 kernel for TQM850L
4599 Created: Wed Jul 19 02:34:59 2000
4600 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4601 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4602 Load Address: 0x00000000
4603 Entry Point: 0x00000000
4605 NOTE: for embedded systems where boot time is critical you can trade
4606 speed for memory and install an UNCOMPRESSED image instead: this
4607 needs more space in Flash, but boots much faster since it does not
4608 need to be uncompressed:
4610 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4611 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4612 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4613 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4614 > examples/uImage.TQM850L-uncompressed
4615 Image Name: 2.4.4 kernel for TQM850L
4616 Created: Wed Jul 19 02:34:59 2000
4617 Image Type: PowerPC Linux Kernel Image (uncompressed)
4618 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4619 Load Address: 0x00000000
4620 Entry Point: 0x00000000
4623 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4624 when your kernel is intended to use an initial ramdisk:
4626 -> tools/mkimage -n 'Simple Ramdisk Image' \
4627 > -A ppc -O linux -T ramdisk -C gzip \
4628 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4629 Image Name: Simple Ramdisk Image
4630 Created: Wed Jan 12 14:01:50 2000
4631 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4632 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4633 Load Address: 0x00000000
4634 Entry Point: 0x00000000
4637 Installing a Linux Image:
4638 -------------------------
4640 To downloading a U-Boot image over the serial (console) interface,
4641 you must convert the image to S-Record format:
4643 objcopy -I binary -O srec examples/image examples/image.srec
4645 The 'objcopy' does not understand the information in the U-Boot
4646 image header, so the resulting S-Record file will be relative to
4647 address 0x00000000. To load it to a given address, you need to
4648 specify the target address as 'offset' parameter with the 'loads'
4651 Example: install the image to address 0x40100000 (which on the
4652 TQM8xxL is in the first Flash bank):
4654 => erase 40100000 401FFFFF
4660 ## Ready for S-Record download ...
4661 ~>examples/image.srec
4662 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4664 15989 15990 15991 15992
4665 [file transfer complete]
4667 ## Start Addr = 0x00000000
4670 You can check the success of the download using the 'iminfo' command;
4671 this includes a checksum verification so you can be sure no data
4672 corruption happened:
4676 ## Checking Image at 40100000 ...
4677 Image Name: 2.2.13 for initrd on TQM850L
4678 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4679 Data Size: 335725 Bytes = 327 kB = 0 MB
4680 Load Address: 00000000
4681 Entry Point: 0000000c
4682 Verifying Checksum ... OK
4688 The "bootm" command is used to boot an application that is stored in
4689 memory (RAM or Flash). In case of a Linux kernel image, the contents
4690 of the "bootargs" environment variable is passed to the kernel as
4691 parameters. You can check and modify this variable using the
4692 "printenv" and "setenv" commands:
4695 => printenv bootargs
4696 bootargs=root=/dev/ram
4698 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4700 => printenv bootargs
4701 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4704 ## Booting Linux kernel at 40020000 ...
4705 Image Name: 2.2.13 for NFS on TQM850L
4706 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4707 Data Size: 381681 Bytes = 372 kB = 0 MB
4708 Load Address: 00000000
4709 Entry Point: 0000000c
4710 Verifying Checksum ... OK
4711 Uncompressing Kernel Image ... OK
4712 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
4713 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4714 time_init: decrementer frequency = 187500000/60
4715 Calibrating delay loop... 49.77 BogoMIPS
4716 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4719 If you want to boot a Linux kernel with initial RAM disk, you pass
4720 the memory addresses of both the kernel and the initrd image (PPBCOOT
4721 format!) to the "bootm" command:
4723 => imi 40100000 40200000
4725 ## Checking Image at 40100000 ...
4726 Image Name: 2.2.13 for initrd on TQM850L
4727 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4728 Data Size: 335725 Bytes = 327 kB = 0 MB
4729 Load Address: 00000000
4730 Entry Point: 0000000c
4731 Verifying Checksum ... OK
4733 ## Checking Image at 40200000 ...
4734 Image Name: Simple Ramdisk Image
4735 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4736 Data Size: 566530 Bytes = 553 kB = 0 MB
4737 Load Address: 00000000
4738 Entry Point: 00000000
4739 Verifying Checksum ... OK
4741 => bootm 40100000 40200000
4742 ## Booting Linux kernel at 40100000 ...
4743 Image Name: 2.2.13 for initrd on TQM850L
4744 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4745 Data Size: 335725 Bytes = 327 kB = 0 MB
4746 Load Address: 00000000
4747 Entry Point: 0000000c
4748 Verifying Checksum ... OK
4749 Uncompressing Kernel Image ... OK
4750 ## Loading RAMDisk Image at 40200000 ...
4751 Image Name: Simple Ramdisk Image
4752 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4753 Data Size: 566530 Bytes = 553 kB = 0 MB
4754 Load Address: 00000000
4755 Entry Point: 00000000
4756 Verifying Checksum ... OK
4757 Loading Ramdisk ... OK
4758 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
4759 Boot arguments: root=/dev/ram
4760 time_init: decrementer frequency = 187500000/60
4761 Calibrating delay loop... 49.77 BogoMIPS
4763 RAMDISK: Compressed image found at block 0
4764 VFS: Mounted root (ext2 filesystem).
4768 Boot Linux and pass a flat device tree:
4771 First, U-Boot must be compiled with the appropriate defines. See the section
4772 titled "Linux Kernel Interface" above for a more in depth explanation. The
4773 following is an example of how to start a kernel and pass an updated
4779 oft=oftrees/mpc8540ads.dtb
4780 => tftp $oftaddr $oft
4781 Speed: 1000, full duplex
4783 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4784 Filename 'oftrees/mpc8540ads.dtb'.
4785 Load address: 0x300000
4788 Bytes transferred = 4106 (100a hex)
4789 => tftp $loadaddr $bootfile
4790 Speed: 1000, full duplex
4792 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4794 Load address: 0x200000
4795 Loading:############
4797 Bytes transferred = 1029407 (fb51f hex)
4802 => bootm $loadaddr - $oftaddr
4803 ## Booting image at 00200000 ...
4804 Image Name: Linux-2.6.17-dirty
4805 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4806 Data Size: 1029343 Bytes = 1005.2 kB
4807 Load Address: 00000000
4808 Entry Point: 00000000
4809 Verifying Checksum ... OK
4810 Uncompressing Kernel Image ... OK
4811 Booting using flat device tree at 0x300000
4812 Using MPC85xx ADS machine description
4813 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4817 More About U-Boot Image Types:
4818 ------------------------------
4820 U-Boot supports the following image types:
4822 "Standalone Programs" are directly runnable in the environment
4823 provided by U-Boot; it is expected that (if they behave
4824 well) you can continue to work in U-Boot after return from
4825 the Standalone Program.
4826 "OS Kernel Images" are usually images of some Embedded OS which
4827 will take over control completely. Usually these programs
4828 will install their own set of exception handlers, device
4829 drivers, set up the MMU, etc. - this means, that you cannot
4830 expect to re-enter U-Boot except by resetting the CPU.
4831 "RAMDisk Images" are more or less just data blocks, and their
4832 parameters (address, size) are passed to an OS kernel that is
4834 "Multi-File Images" contain several images, typically an OS
4835 (Linux) kernel image and one or more data images like
4836 RAMDisks. This construct is useful for instance when you want
4837 to boot over the network using BOOTP etc., where the boot
4838 server provides just a single image file, but you want to get
4839 for instance an OS kernel and a RAMDisk image.
4841 "Multi-File Images" start with a list of image sizes, each
4842 image size (in bytes) specified by an "uint32_t" in network
4843 byte order. This list is terminated by an "(uint32_t)0".
4844 Immediately after the terminating 0 follow the images, one by
4845 one, all aligned on "uint32_t" boundaries (size rounded up to
4846 a multiple of 4 bytes).
4848 "Firmware Images" are binary images containing firmware (like
4849 U-Boot or FPGA images) which usually will be programmed to
4852 "Script files" are command sequences that will be executed by
4853 U-Boot's command interpreter; this feature is especially
4854 useful when you configure U-Boot to use a real shell (hush)
4855 as command interpreter.
4857 Booting the Linux zImage:
4858 -------------------------
4860 On some platforms, it's possible to boot Linux zImage. This is done
4861 using the "bootz" command. The syntax of "bootz" command is the same
4862 as the syntax of "bootm" command.
4864 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4865 kernel with raw initrd images. The syntax is slightly different, the
4866 address of the initrd must be augmented by it's size, in the following
4867 format: "<initrd addres>:<initrd size>".
4873 One of the features of U-Boot is that you can dynamically load and
4874 run "standalone" applications, which can use some resources of
4875 U-Boot like console I/O functions or interrupt services.
4877 Two simple examples are included with the sources:
4882 'examples/hello_world.c' contains a small "Hello World" Demo
4883 application; it is automatically compiled when you build U-Boot.
4884 It's configured to run at address 0x00040004, so you can play with it
4888 ## Ready for S-Record download ...
4889 ~>examples/hello_world.srec
4890 1 2 3 4 5 6 7 8 9 10 11 ...
4891 [file transfer complete]
4893 ## Start Addr = 0x00040004
4895 => go 40004 Hello World! This is a test.
4896 ## Starting application at 0x00040004 ...
4907 Hit any key to exit ...
4909 ## Application terminated, rc = 0x0
4911 Another example, which demonstrates how to register a CPM interrupt
4912 handler with the U-Boot code, can be found in 'examples/timer.c'.
4913 Here, a CPM timer is set up to generate an interrupt every second.
4914 The interrupt service routine is trivial, just printing a '.'
4915 character, but this is just a demo program. The application can be
4916 controlled by the following keys:
4918 ? - print current values og the CPM Timer registers
4919 b - enable interrupts and start timer
4920 e - stop timer and disable interrupts
4921 q - quit application
4924 ## Ready for S-Record download ...
4925 ~>examples/timer.srec
4926 1 2 3 4 5 6 7 8 9 10 11 ...
4927 [file transfer complete]
4929 ## Start Addr = 0x00040004
4932 ## Starting application at 0x00040004 ...
4935 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4938 [q, b, e, ?] Set interval 1000000 us
4941 [q, b, e, ?] ........
4942 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4945 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4948 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4951 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4953 [q, b, e, ?] ...Stopping timer
4955 [q, b, e, ?] ## Application terminated, rc = 0x0
4961 Over time, many people have reported problems when trying to use the
4962 "minicom" terminal emulation program for serial download. I (wd)
4963 consider minicom to be broken, and recommend not to use it. Under
4964 Unix, I recommend to use C-Kermit for general purpose use (and
4965 especially for kermit binary protocol download ("loadb" command), and
4966 use "cu" for S-Record download ("loads" command). See
4967 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4968 for help with kermit.
4971 Nevertheless, if you absolutely want to use it try adding this
4972 configuration to your "File transfer protocols" section:
4974 Name Program Name U/D FullScr IO-Red. Multi
4975 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4976 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4982 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4983 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4985 Building requires a cross environment; it is known to work on
4986 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4987 need gmake since the Makefiles are not compatible with BSD make).
4988 Note that the cross-powerpc package does not install include files;
4989 attempting to build U-Boot will fail because <machine/ansi.h> is
4990 missing. This file has to be installed and patched manually:
4992 # cd /usr/pkg/cross/powerpc-netbsd/include
4994 # ln -s powerpc machine
4995 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4996 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4998 Native builds *don't* work due to incompatibilities between native
4999 and U-Boot include files.
5001 Booting assumes that (the first part of) the image booted is a
5002 stage-2 loader which in turn loads and then invokes the kernel
5003 proper. Loader sources will eventually appear in the NetBSD source
5004 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5005 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5008 Implementation Internals:
5009 =========================
5011 The following is not intended to be a complete description of every
5012 implementation detail. However, it should help to understand the
5013 inner workings of U-Boot and make it easier to port it to custom
5017 Initial Stack, Global Data:
5018 ---------------------------
5020 The implementation of U-Boot is complicated by the fact that U-Boot
5021 starts running out of ROM (flash memory), usually without access to
5022 system RAM (because the memory controller is not initialized yet).
5023 This means that we don't have writable Data or BSS segments, and BSS
5024 is not initialized as zero. To be able to get a C environment working
5025 at all, we have to allocate at least a minimal stack. Implementation
5026 options for this are defined and restricted by the CPU used: Some CPU
5027 models provide on-chip memory (like the IMMR area on MPC8xx and
5028 MPC826x processors), on others (parts of) the data cache can be
5029 locked as (mis-) used as memory, etc.
5031 Chris Hallinan posted a good summary of these issues to the
5032 U-Boot mailing list:
5034 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5035 From: "Chris Hallinan" <clh@net1plus.com>
5036 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5039 Correct me if I'm wrong, folks, but the way I understand it
5040 is this: Using DCACHE as initial RAM for Stack, etc, does not
5041 require any physical RAM backing up the cache. The cleverness
5042 is that the cache is being used as a temporary supply of
5043 necessary storage before the SDRAM controller is setup. It's
5044 beyond the scope of this list to explain the details, but you
5045 can see how this works by studying the cache architecture and
5046 operation in the architecture and processor-specific manuals.
5048 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5049 is another option for the system designer to use as an
5050 initial stack/RAM area prior to SDRAM being available. Either
5051 option should work for you. Using CS 4 should be fine if your
5052 board designers haven't used it for something that would
5053 cause you grief during the initial boot! It is frequently not
5056 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5057 with your processor/board/system design. The default value
5058 you will find in any recent u-boot distribution in
5059 walnut.h should work for you. I'd set it to a value larger
5060 than your SDRAM module. If you have a 64MB SDRAM module, set
5061 it above 400_0000. Just make sure your board has no resources
5062 that are supposed to respond to that address! That code in
5063 start.S has been around a while and should work as is when
5064 you get the config right.
5069 It is essential to remember this, since it has some impact on the C
5070 code for the initialization procedures:
5072 * Initialized global data (data segment) is read-only. Do not attempt
5075 * Do not use any uninitialized global data (or implicitely initialized
5076 as zero data - BSS segment) at all - this is undefined, initiali-
5077 zation is performed later (when relocating to RAM).
5079 * Stack space is very limited. Avoid big data buffers or things like
5082 Having only the stack as writable memory limits means we cannot use
5083 normal global data to share information beween the code. But it
5084 turned out that the implementation of U-Boot can be greatly
5085 simplified by making a global data structure (gd_t) available to all
5086 functions. We could pass a pointer to this data as argument to _all_
5087 functions, but this would bloat the code. Instead we use a feature of
5088 the GCC compiler (Global Register Variables) to share the data: we
5089 place a pointer (gd) to the global data into a register which we
5090 reserve for this purpose.
5092 When choosing a register for such a purpose we are restricted by the
5093 relevant (E)ABI specifications for the current architecture, and by
5094 GCC's implementation.
5096 For PowerPC, the following registers have specific use:
5098 R2: reserved for system use
5099 R3-R4: parameter passing and return values
5100 R5-R10: parameter passing
5101 R13: small data area pointer
5105 (U-Boot also uses R12 as internal GOT pointer. r12
5106 is a volatile register so r12 needs to be reset when
5107 going back and forth between asm and C)
5109 ==> U-Boot will use R2 to hold a pointer to the global data
5111 Note: on PPC, we could use a static initializer (since the
5112 address of the global data structure is known at compile time),
5113 but it turned out that reserving a register results in somewhat
5114 smaller code - although the code savings are not that big (on
5115 average for all boards 752 bytes for the whole U-Boot image,
5116 624 text + 127 data).
5118 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5119 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5121 ==> U-Boot will use P3 to hold a pointer to the global data
5123 On ARM, the following registers are used:
5125 R0: function argument word/integer result
5126 R1-R3: function argument word
5128 R10: stack limit (used only if stack checking if enabled)
5129 R11: argument (frame) pointer
5130 R12: temporary workspace
5133 R15: program counter
5135 ==> U-Boot will use R8 to hold a pointer to the global data
5137 On Nios II, the ABI is documented here:
5138 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5140 ==> U-Boot will use gp to hold a pointer to the global data
5142 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5143 to access small data sections, so gp is free.
5145 On NDS32, the following registers are used:
5147 R0-R1: argument/return
5149 R15: temporary register for assembler
5150 R16: trampoline register
5151 R28: frame pointer (FP)
5152 R29: global pointer (GP)
5153 R30: link register (LP)
5154 R31: stack pointer (SP)
5155 PC: program counter (PC)
5157 ==> U-Boot will use R10 to hold a pointer to the global data
5159 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5160 or current versions of GCC may "optimize" the code too much.
5165 U-Boot runs in system state and uses physical addresses, i.e. the
5166 MMU is not used either for address mapping nor for memory protection.
5168 The available memory is mapped to fixed addresses using the memory
5169 controller. In this process, a contiguous block is formed for each
5170 memory type (Flash, SDRAM, SRAM), even when it consists of several
5171 physical memory banks.
5173 U-Boot is installed in the first 128 kB of the first Flash bank (on
5174 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5175 booting and sizing and initializing DRAM, the code relocates itself
5176 to the upper end of DRAM. Immediately below the U-Boot code some
5177 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5178 configuration setting]. Below that, a structure with global Board
5179 Info data is placed, followed by the stack (growing downward).
5181 Additionally, some exception handler code is copied to the low 8 kB
5182 of DRAM (0x00000000 ... 0x00001FFF).
5184 So a typical memory configuration with 16 MB of DRAM could look like
5187 0x0000 0000 Exception Vector code
5190 0x0000 2000 Free for Application Use
5196 0x00FB FF20 Monitor Stack (Growing downward)
5197 0x00FB FFAC Board Info Data and permanent copy of global data
5198 0x00FC 0000 Malloc Arena
5201 0x00FE 0000 RAM Copy of Monitor Code
5202 ... eventually: LCD or video framebuffer
5203 ... eventually: pRAM (Protected RAM - unchanged by reset)
5204 0x00FF FFFF [End of RAM]
5207 System Initialization:
5208 ----------------------
5210 In the reset configuration, U-Boot starts at the reset entry point
5211 (on most PowerPC systems at address 0x00000100). Because of the reset
5212 configuration for CS0# this is a mirror of the onboard Flash memory.
5213 To be able to re-map memory U-Boot then jumps to its link address.
5214 To be able to implement the initialization code in C, a (small!)
5215 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5216 which provide such a feature like MPC8xx or MPC8260), or in a locked
5217 part of the data cache. After that, U-Boot initializes the CPU core,
5218 the caches and the SIU.
5220 Next, all (potentially) available memory banks are mapped using a
5221 preliminary mapping. For example, we put them on 512 MB boundaries
5222 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5223 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5224 programmed for SDRAM access. Using the temporary configuration, a
5225 simple memory test is run that determines the size of the SDRAM
5228 When there is more than one SDRAM bank, and the banks are of
5229 different size, the largest is mapped first. For equal size, the first
5230 bank (CS2#) is mapped first. The first mapping is always for address
5231 0x00000000, with any additional banks following immediately to create
5232 contiguous memory starting from 0.
5234 Then, the monitor installs itself at the upper end of the SDRAM area
5235 and allocates memory for use by malloc() and for the global Board
5236 Info data; also, the exception vector code is copied to the low RAM
5237 pages, and the final stack is set up.
5239 Only after this relocation will you have a "normal" C environment;
5240 until that you are restricted in several ways, mostly because you are
5241 running from ROM, and because the code will have to be relocated to a
5245 U-Boot Porting Guide:
5246 ----------------------
5248 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5252 int main(int argc, char *argv[])
5254 sighandler_t no_more_time;
5256 signal(SIGALRM, no_more_time);
5257 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5259 if (available_money > available_manpower) {
5260 Pay consultant to port U-Boot;
5264 Download latest U-Boot source;
5266 Subscribe to u-boot mailing list;
5269 email("Hi, I am new to U-Boot, how do I get started?");
5272 Read the README file in the top level directory;
5273 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5274 Read applicable doc/*.README;
5275 Read the source, Luke;
5276 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5279 if (available_money > toLocalCurrency ($2500))
5282 Add a lot of aggravation and time;
5284 if (a similar board exists) { /* hopefully... */
5285 cp -a board/<similar> board/<myboard>
5286 cp include/configs/<similar>.h include/configs/<myboard>.h
5288 Create your own board support subdirectory;
5289 Create your own board include/configs/<myboard>.h file;
5291 Edit new board/<myboard> files
5292 Edit new include/configs/<myboard>.h
5297 Add / modify source code;
5301 email("Hi, I am having problems...");
5303 Send patch file to the U-Boot email list;
5304 if (reasonable critiques)
5305 Incorporate improvements from email list code review;
5307 Defend code as written;
5313 void no_more_time (int sig)
5322 All contributions to U-Boot should conform to the Linux kernel
5323 coding style; see the file "Documentation/CodingStyle" and the script
5324 "scripts/Lindent" in your Linux kernel source directory.
5326 Source files originating from a different project (for example the
5327 MTD subsystem) are generally exempt from these guidelines and are not
5328 reformated to ease subsequent migration to newer versions of those
5331 Please note that U-Boot is implemented in C (and to some small parts in
5332 Assembler); no C++ is used, so please do not use C++ style comments (//)
5335 Please also stick to the following formatting rules:
5336 - remove any trailing white space
5337 - use TAB characters for indentation and vertical alignment, not spaces
5338 - make sure NOT to use DOS '\r\n' line feeds
5339 - do not add more than 2 consecutive empty lines to source files
5340 - do not add trailing empty lines to source files
5342 Submissions which do not conform to the standards may be returned
5343 with a request to reformat the changes.
5349 Since the number of patches for U-Boot is growing, we need to
5350 establish some rules. Submissions which do not conform to these rules
5351 may be rejected, even when they contain important and valuable stuff.
5353 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5355 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5356 see http://lists.denx.de/mailman/listinfo/u-boot
5358 When you send a patch, please include the following information with
5361 * For bug fixes: a description of the bug and how your patch fixes
5362 this bug. Please try to include a way of demonstrating that the
5363 patch actually fixes something.
5365 * For new features: a description of the feature and your
5368 * A CHANGELOG entry as plaintext (separate from the patch)
5370 * For major contributions, your entry to the CREDITS file
5372 * When you add support for a new board, don't forget to add this
5373 board to the MAINTAINERS file, too.
5375 * If your patch adds new configuration options, don't forget to
5376 document these in the README file.
5378 * The patch itself. If you are using git (which is *strongly*
5379 recommended) you can easily generate the patch using the
5380 "git format-patch". If you then use "git send-email" to send it to
5381 the U-Boot mailing list, you will avoid most of the common problems
5382 with some other mail clients.
5384 If you cannot use git, use "diff -purN OLD NEW". If your version of
5385 diff does not support these options, then get the latest version of
5388 The current directory when running this command shall be the parent
5389 directory of the U-Boot source tree (i. e. please make sure that
5390 your patch includes sufficient directory information for the
5393 We prefer patches as plain text. MIME attachments are discouraged,
5394 and compressed attachments must not be used.
5396 * If one logical set of modifications affects or creates several
5397 files, all these changes shall be submitted in a SINGLE patch file.
5399 * Changesets that contain different, unrelated modifications shall be
5400 submitted as SEPARATE patches, one patch per changeset.
5405 * Before sending the patch, run the MAKEALL script on your patched
5406 source tree and make sure that no errors or warnings are reported
5407 for any of the boards.
5409 * Keep your modifications to the necessary minimum: A patch
5410 containing several unrelated changes or arbitrary reformats will be
5411 returned with a request to re-formatting / split it.
5413 * If you modify existing code, make sure that your new code does not
5414 add to the memory footprint of the code ;-) Small is beautiful!
5415 When adding new features, these should compile conditionally only
5416 (using #ifdef), and the resulting code with the new feature
5417 disabled must not need more memory than the old code without your
5420 * Remember that there is a size limit of 100 kB per message on the
5421 u-boot mailing list. Bigger patches will be moderated. If they are
5422 reasonable and not too big, they will be acknowledged. But patches
5423 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob