2 # (C) Copyright 2000 - 2012
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
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 /mpc824x Files specific to Freescale MPC824x CPUs
205 /mpc8260 Files specific to Freescale MPC8260 CPUs
206 /mpc85xx Files specific to Freescale MPC85xx CPUs
207 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
208 /lib Architecture specific library files
209 /sh Files generic to SH architecture
210 /cpu CPU specific files
211 /sh2 Files specific to sh2 CPUs
212 /sh3 Files specific to sh3 CPUs
213 /sh4 Files specific to sh4 CPUs
214 /lib Architecture specific library files
215 /sparc Files generic to SPARC architecture
216 /cpu CPU specific files
217 /leon2 Files specific to Gaisler LEON2 SPARC CPU
218 /leon3 Files specific to Gaisler LEON3 SPARC CPU
219 /lib Architecture specific library files
220 /api Machine/arch independent API for external apps
221 /board Board dependent files
222 /common Misc architecture independent functions
223 /disk Code for disk drive partition handling
224 /doc Documentation (don't expect too much)
225 /drivers Commonly used device drivers
226 /examples Example code for standalone applications, etc.
227 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
228 /include Header Files
229 /lib Files generic to all architectures
230 /libfdt Library files to support flattened device trees
231 /lzma Library files to support LZMA decompression
232 /lzo Library files to support LZO decompression
234 /post Power On Self Test
235 /rtc Real Time Clock drivers
236 /tools Tools to build S-Record or U-Boot images, etc.
238 Software Configuration:
239 =======================
241 Configuration is usually done using C preprocessor defines; the
242 rationale behind that is to avoid dead code whenever possible.
244 There are two classes of configuration variables:
246 * Configuration _OPTIONS_:
247 These are selectable by the user and have names beginning with
250 * Configuration _SETTINGS_:
251 These depend on the hardware etc. and should not be meddled with if
252 you don't know what you're doing; they have names beginning with
255 Later we will add a configuration tool - probably similar to or even
256 identical to what's used for the Linux kernel. Right now, we have to
257 do the configuration by hand, which means creating some symbolic
258 links and editing some configuration files. We use the TQM8xxL boards
262 Selection of Processor Architecture and Board Type:
263 ---------------------------------------------------
265 For all supported boards there are ready-to-use default
266 configurations available; just type "make <board_name>_config".
268 Example: For a TQM823L module type:
273 For the Cogent platform, you need to specify the CPU type as well;
274 e.g. "make cogent_mpc8xx_config". And also configure the cogent
275 directory according to the instructions in cogent/README.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Board flavour: (if CONFIG_MPC8260ADS is defined)
327 CONFIG_SYS_8260ADS - original MPC8260ADS
328 CONFIG_SYS_8266ADS - MPC8266ADS
329 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
330 CONFIG_SYS_8272ADS - MPC8272ADS
332 - Marvell Family Member
333 CONFIG_SYS_MVFS - define it if you want to enable
334 multiple fs option at one time
335 for marvell soc family
337 - MPC824X Family Member (if CONFIG_MPC824X is defined)
338 Define exactly one of
339 CONFIG_MPC8240, CONFIG_MPC8245
341 - 8xx CPU Options: (if using an MPC8xx CPU)
342 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
343 get_gclk_freq() cannot work
344 e.g. if there is no 32KHz
345 reference PIT/RTC clock
346 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
349 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
350 CONFIG_SYS_8xx_CPUCLK_MIN
351 CONFIG_SYS_8xx_CPUCLK_MAX
352 CONFIG_8xx_CPUCLK_DEFAULT
353 See doc/README.MPC866
355 CONFIG_SYS_MEASURE_CPUCLK
357 Define this to measure the actual CPU clock instead
358 of relying on the correctness of the configured
359 values. Mostly useful for board bringup to make sure
360 the PLL is locked at the intended frequency. Note
361 that this requires a (stable) reference clock (32 kHz
362 RTC clock or CONFIG_SYS_8XX_XIN)
364 CONFIG_SYS_DELAYED_ICACHE
366 Define this option if you want to enable the
367 ICache only when Code runs from RAM.
372 Specifies that the core is a 64-bit PowerPC implementation (implements
373 the "64" category of the Power ISA). This is necessary for ePAPR
374 compliance, among other possible reasons.
376 CONFIG_SYS_FSL_TBCLK_DIV
378 Defines the core time base clock divider ratio compared to the
379 system clock. On most PQ3 devices this is 8, on newer QorIQ
380 devices it can be 16 or 32. The ratio varies from SoC to Soc.
382 CONFIG_SYS_FSL_PCIE_COMPAT
384 Defines the string to utilize when trying to match PCIe device
385 tree nodes for the given platform.
387 CONFIG_SYS_PPC_E500_DEBUG_TLB
389 Enables a temporary TLB entry to be used during boot to work
390 around limitations in e500v1 and e500v2 external debugger
391 support. This reduces the portions of the boot code where
392 breakpoints and single stepping do not work. The value of this
393 symbol should be set to the TLB1 entry to be used for this
396 CONFIG_SYS_FSL_ERRATUM_A004510
398 Enables a workaround for erratum A004510. If set,
399 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
400 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
402 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
405 Defines one or two SoC revisions (low 8 bits of SVR)
406 for which the A004510 workaround should be applied.
408 The rest of SVR is either not relevant to the decision
409 of whether the erratum is present (e.g. p2040 versus
410 p2041) or is implied by the build target, which controls
411 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
413 See Freescale App Note 4493 for more information about
416 CONFIG_A003399_NOR_WORKAROUND
417 Enables a workaround for IFC erratum A003399. It is only
418 requred during NOR boot.
420 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
422 This is the value to write into CCSR offset 0x18600
423 according to the A004510 workaround.
425 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
426 This value denotes start offset of M2 memory
427 which is directly connected to the DSP core.
429 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
430 This value denotes start offset of DSP CCSR space.
432 - Generic CPU options:
433 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
435 Defines the endianess of the CPU. Implementation of those
436 values is arch specific.
438 - Intel Monahans options:
439 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
441 Defines the Monahans run mode to oscillator
442 ratio. Valid values are 8, 16, 24, 31. The core
443 frequency is this value multiplied by 13 MHz.
445 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
447 Defines the Monahans turbo mode to oscillator
448 ratio. Valid values are 1 (default if undefined) and
449 2. The core frequency as calculated above is multiplied
453 CONFIG_SYS_INIT_SP_OFFSET
455 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
456 pointer. This is needed for the temporary stack before
459 CONFIG_SYS_MIPS_CACHE_MODE
461 Cache operation mode for the MIPS CPU.
462 See also arch/mips/include/asm/mipsregs.h.
464 CONF_CM_CACHABLE_NO_WA
467 CONF_CM_CACHABLE_NONCOHERENT
471 CONF_CM_CACHABLE_ACCELERATED
473 CONFIG_SYS_XWAY_EBU_BOOTCFG
475 Special option for Lantiq XWAY SoCs for booting from NOR flash.
476 See also arch/mips/cpu/mips32/start.S.
478 CONFIG_XWAY_SWAP_BYTES
480 Enable compilation of tools/xway-swap-bytes needed for Lantiq
481 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
482 be swapped if a flash programmer is used.
485 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
487 Select high exception vectors of the ARM core, e.g., do not
488 clear the V bit of the c1 register of CP15.
490 CONFIG_SYS_THUMB_BUILD
492 Use this flag to build U-Boot using the Thumb instruction
493 set for ARM architectures. Thumb instruction set provides
494 better code density. For ARM architectures that support
495 Thumb2 this flag will result in Thumb2 code generated by
498 CONFIG_ARM_ERRATA_716044
499 CONFIG_ARM_ERRATA_742230
500 CONFIG_ARM_ERRATA_743622
501 CONFIG_ARM_ERRATA_751472
503 If set, the workarounds for these ARM errata are applied early
504 during U-Boot startup. Note that these options force the
505 workarounds to be applied; no CPU-type/version detection
506 exists, unlike the similar options in the Linux kernel. Do not
507 set these options unless they apply!
512 The frequency of the timer returned by get_timer().
513 get_timer() must operate in milliseconds and this CONFIG
514 option must be set to 1000.
516 - Linux Kernel Interface:
519 U-Boot stores all clock information in Hz
520 internally. For binary compatibility with older Linux
521 kernels (which expect the clocks passed in the
522 bd_info data to be in MHz) the environment variable
523 "clocks_in_mhz" can be defined so that U-Boot
524 converts clock data to MHZ before passing it to the
526 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
527 "clocks_in_mhz=1" is automatically included in the
530 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
532 When transferring memsize parameter to linux, some versions
533 expect it to be in bytes, others in MB.
534 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
538 New kernel versions are expecting firmware settings to be
539 passed using flattened device trees (based on open firmware
543 * New libfdt-based support
544 * Adds the "fdt" command
545 * The bootm command automatically updates the fdt
547 OF_CPU - The proper name of the cpus node (only required for
548 MPC512X and MPC5xxx based boards).
549 OF_SOC - The proper name of the soc node (only required for
550 MPC512X and MPC5xxx based boards).
551 OF_TBCLK - The timebase frequency.
552 OF_STDOUT_PATH - The path to the console device
554 boards with QUICC Engines require OF_QE to set UCC MAC
557 CONFIG_OF_BOARD_SETUP
559 Board code has addition modification that it wants to make
560 to the flat device tree before handing it off to the kernel
564 This define fills in the correct boot CPU in the boot
565 param header, the default value is zero if undefined.
569 U-Boot can detect if an IDE device is present or not.
570 If not, and this new config option is activated, U-Boot
571 removes the ATA node from the DTS before booting Linux,
572 so the Linux IDE driver does not probe the device and
573 crash. This is needed for buggy hardware (uc101) where
574 no pull down resistor is connected to the signal IDE5V_DD7.
576 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
578 This setting is mandatory for all boards that have only one
579 machine type and must be used to specify the machine type
580 number as it appears in the ARM machine registry
581 (see http://www.arm.linux.org.uk/developer/machines/).
582 Only boards that have multiple machine types supported
583 in a single configuration file and the machine type is
584 runtime discoverable, do not have to use this setting.
586 - vxWorks boot parameters:
588 bootvx constructs a valid bootline using the following
589 environments variables: bootfile, ipaddr, serverip, hostname.
590 It loads the vxWorks image pointed bootfile.
592 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
593 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
594 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
595 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
597 CONFIG_SYS_VXWORKS_ADD_PARAMS
599 Add it at the end of the bootline. E.g "u=username pw=secret"
601 Note: If a "bootargs" environment is defined, it will overwride
602 the defaults discussed just above.
604 - Cache Configuration:
605 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
606 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
607 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
609 - Cache Configuration for ARM:
610 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
612 CONFIG_SYS_PL310_BASE - Physical base address of PL310
613 controller register space
618 Define this if you want support for Amba PrimeCell PL010 UARTs.
622 Define this if you want support for Amba PrimeCell PL011 UARTs.
626 If you have Amba PrimeCell PL011 UARTs, set this variable to
627 the clock speed of the UARTs.
631 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
632 define this to a list of base addresses for each (supported)
633 port. See e.g. include/configs/versatile.h
635 CONFIG_PL011_SERIAL_RLCR
637 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
638 have separate receive and transmit line control registers. Set
639 this variable to initialize the extra register.
641 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
643 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
644 boot loader that has already initialized the UART. Define this
645 variable to flush the UART at init time.
649 Depending on board, define exactly one serial port
650 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
651 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
652 console by defining CONFIG_8xx_CONS_NONE
654 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
655 port routines must be defined elsewhere
656 (i.e. serial_init(), serial_getc(), ...)
659 Enables console device for a color framebuffer. Needs following
660 defines (cf. smiLynxEM, i8042)
661 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
663 VIDEO_HW_RECTFILL graphic chip supports
666 VIDEO_HW_BITBLT graphic chip supports
667 bit-blit (cf. smiLynxEM)
668 VIDEO_VISIBLE_COLS visible pixel columns
670 VIDEO_VISIBLE_ROWS visible pixel rows
671 VIDEO_PIXEL_SIZE bytes per pixel
672 VIDEO_DATA_FORMAT graphic data format
673 (0-5, cf. cfb_console.c)
674 VIDEO_FB_ADRS framebuffer address
675 VIDEO_KBD_INIT_FCT keyboard int fct
676 (i.e. i8042_kbd_init())
677 VIDEO_TSTC_FCT test char fct
679 VIDEO_GETC_FCT get char fct
681 CONFIG_CONSOLE_CURSOR cursor drawing on/off
682 (requires blink timer
684 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
685 CONFIG_CONSOLE_TIME display time/date info in
687 (requires CONFIG_CMD_DATE)
688 CONFIG_VIDEO_LOGO display Linux logo in
690 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
691 linux_logo.h for logo.
692 Requires CONFIG_VIDEO_LOGO
693 CONFIG_CONSOLE_EXTRA_INFO
694 additional board info beside
697 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
698 a limited number of ANSI escape sequences (cursor control,
699 erase functions and limited graphics rendition control).
701 When CONFIG_CFB_CONSOLE is defined, video console is
702 default i/o. Serial console can be forced with
703 environment 'console=serial'.
705 When CONFIG_SILENT_CONSOLE is defined, all console
706 messages (by U-Boot and Linux!) can be silenced with
707 the "silent" environment variable. See
708 doc/README.silent for more information.
711 CONFIG_BAUDRATE - in bps
712 Select one of the baudrates listed in
713 CONFIG_SYS_BAUDRATE_TABLE, see below.
714 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
716 - Console Rx buffer length
717 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
718 the maximum receive buffer length for the SMC.
719 This option is actual only for 82xx and 8xx possible.
720 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
721 must be defined, to setup the maximum idle timeout for
724 - Pre-Console Buffer:
725 Prior to the console being initialised (i.e. serial UART
726 initialised etc) all console output is silently discarded.
727 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
728 buffer any console messages prior to the console being
729 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
730 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
731 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
732 bytes are output before the console is initialised, the
733 earlier bytes are discarded.
735 'Sane' compilers will generate smaller code if
736 CONFIG_PRE_CON_BUF_SZ is a power of 2
738 - Safe printf() functions
739 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
740 the printf() functions. These are defined in
741 include/vsprintf.h and include snprintf(), vsnprintf() and
742 so on. Code size increase is approximately 300-500 bytes.
743 If this option is not given then these functions will
744 silently discard their buffer size argument - this means
745 you are not getting any overflow checking in this case.
747 - Boot Delay: CONFIG_BOOTDELAY - in seconds
748 Delay before automatically booting the default image;
749 set to -1 to disable autoboot.
750 set to -2 to autoboot with no delay and not check for abort
751 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
753 See doc/README.autoboot for these options that
754 work with CONFIG_BOOTDELAY. None are required.
755 CONFIG_BOOT_RETRY_TIME
756 CONFIG_BOOT_RETRY_MIN
757 CONFIG_AUTOBOOT_KEYED
758 CONFIG_AUTOBOOT_PROMPT
759 CONFIG_AUTOBOOT_DELAY_STR
760 CONFIG_AUTOBOOT_STOP_STR
761 CONFIG_AUTOBOOT_DELAY_STR2
762 CONFIG_AUTOBOOT_STOP_STR2
763 CONFIG_ZERO_BOOTDELAY_CHECK
764 CONFIG_RESET_TO_RETRY
768 Only needed when CONFIG_BOOTDELAY is enabled;
769 define a command string that is automatically executed
770 when no character is read on the console interface
771 within "Boot Delay" after reset.
774 This can be used to pass arguments to the bootm
775 command. The value of CONFIG_BOOTARGS goes into the
776 environment value "bootargs".
778 CONFIG_RAMBOOT and CONFIG_NFSBOOT
779 The value of these goes into the environment as
780 "ramboot" and "nfsboot" respectively, and can be used
781 as a convenience, when switching between booting from
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or using <config_cmd_default.h>
819 and augmenting with additional #define's
822 The default command configuration includes all commands
823 except those marked below with a "*".
825 CONFIG_CMD_ASKENV * ask for env variable
826 CONFIG_CMD_BDI bdinfo
827 CONFIG_CMD_BEDBUG * Include BedBug Debugger
828 CONFIG_CMD_BMP * BMP support
829 CONFIG_CMD_BSP * Board specific commands
830 CONFIG_CMD_BOOTD bootd
831 CONFIG_CMD_CACHE * icache, dcache
832 CONFIG_CMD_CONSOLE coninfo
833 CONFIG_CMD_CRC32 * crc32
834 CONFIG_CMD_DATE * support for RTC, date/time...
835 CONFIG_CMD_DHCP * DHCP support
836 CONFIG_CMD_DIAG * Diagnostics
837 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
838 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
839 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
840 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
841 CONFIG_CMD_DTT * Digital Therm and Thermostat
842 CONFIG_CMD_ECHO echo arguments
843 CONFIG_CMD_EDITENV edit env variable
844 CONFIG_CMD_EEPROM * EEPROM read/write support
845 CONFIG_CMD_ELF * bootelf, bootvx
846 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
847 CONFIG_CMD_ENV_FLAGS * display details about env flags
848 CONFIG_CMD_EXPORTENV * export the environment
849 CONFIG_CMD_EXT2 * ext2 command support
850 CONFIG_CMD_EXT4 * ext4 command support
851 CONFIG_CMD_SAVEENV saveenv
852 CONFIG_CMD_FDC * Floppy Disk Support
853 CONFIG_CMD_FAT * FAT command support
854 CONFIG_CMD_FDOS * Dos diskette Support
855 CONFIG_CMD_FLASH flinfo, erase, protect
856 CONFIG_CMD_FPGA FPGA device initialization support
857 CONFIG_CMD_FUSE * Device fuse support
858 CONFIG_CMD_GETTIME * Get time since boot
859 CONFIG_CMD_GO * the 'go' command (exec code)
860 CONFIG_CMD_GREPENV * search environment
861 CONFIG_CMD_HASH * calculate hash / digest
862 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
863 CONFIG_CMD_I2C * I2C serial bus support
864 CONFIG_CMD_IDE * IDE harddisk support
865 CONFIG_CMD_IMI iminfo
866 CONFIG_CMD_IMLS List all images found in NOR flash
867 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
868 CONFIG_CMD_IMMAP * IMMR dump support
869 CONFIG_CMD_IMPORTENV * import an environment
870 CONFIG_CMD_INI * import data from an ini file into the env
871 CONFIG_CMD_IRQ * irqinfo
872 CONFIG_CMD_ITEST Integer/string test of 2 values
873 CONFIG_CMD_JFFS2 * JFFS2 Support
874 CONFIG_CMD_KGDB * kgdb
875 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
876 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
878 CONFIG_CMD_LOADB loadb
879 CONFIG_CMD_LOADS loads
880 CONFIG_CMD_MD5SUM * print md5 message digest
881 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
882 CONFIG_CMD_MEMINFO * Display detailed memory information
883 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
885 CONFIG_CMD_MEMTEST * mtest
886 CONFIG_CMD_MISC Misc functions like sleep etc
887 CONFIG_CMD_MMC * MMC memory mapped support
888 CONFIG_CMD_MII * MII utility commands
889 CONFIG_CMD_MTDPARTS * MTD partition support
890 CONFIG_CMD_NAND * NAND support
891 CONFIG_CMD_NET bootp, tftpboot, rarpboot
892 CONFIG_CMD_NFS NFS support
893 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
894 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
895 CONFIG_CMD_PCI * pciinfo
896 CONFIG_CMD_PCMCIA * PCMCIA support
897 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
899 CONFIG_CMD_PORTIO * Port I/O
900 CONFIG_CMD_READ * Read raw data from partition
901 CONFIG_CMD_REGINFO * Register dump
902 CONFIG_CMD_RUN run command in env variable
903 CONFIG_CMD_SANDBOX * sb command to access sandbox features
904 CONFIG_CMD_SAVES * save S record dump
905 CONFIG_CMD_SCSI * SCSI Support
906 CONFIG_CMD_SDRAM * print SDRAM configuration information
907 (requires CONFIG_CMD_I2C)
908 CONFIG_CMD_SETGETDCR Support for DCR Register access
910 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
911 CONFIG_CMD_SHA1SUM * print sha1 memory digest
912 (requires CONFIG_CMD_MEMORY)
913 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
914 CONFIG_CMD_SOURCE "source" command Support
915 CONFIG_CMD_SPI * SPI serial bus support
916 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
917 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
918 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
919 CONFIG_CMD_TIMER * access to the system tick timer
920 CONFIG_CMD_USB * USB support
921 CONFIG_CMD_CDP * Cisco Discover Protocol support
922 CONFIG_CMD_MFSL * Microblaze FSL support
923 CONFIG_CMD_XIMG Load part of Multi Image
926 EXAMPLE: If you want all functions except of network
927 support you can write:
929 #include "config_cmd_all.h"
930 #undef CONFIG_CMD_NET
933 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
935 Note: Don't enable the "icache" and "dcache" commands
936 (configuration option CONFIG_CMD_CACHE) unless you know
937 what you (and your U-Boot users) are doing. Data
938 cache cannot be enabled on systems like the 8xx or
939 8260 (where accesses to the IMMR region must be
940 uncached), and it cannot be disabled on all other
941 systems where we (mis-) use the data cache to hold an
942 initial stack and some data.
945 XXX - this list needs to get updated!
947 - Regular expression support:
949 If this variable is defined, U-Boot is linked against
950 the SLRE (Super Light Regular Expression) library,
951 which adds regex support to some commands, as for
952 example "env grep" and "setexpr".
956 If this variable is defined, U-Boot will use a device tree
957 to configure its devices, instead of relying on statically
958 compiled #defines in the board file. This option is
959 experimental and only available on a few boards. The device
960 tree is available in the global data as gd->fdt_blob.
962 U-Boot needs to get its device tree from somewhere. This can
963 be done using one of the two options below:
966 If this variable is defined, U-Boot will embed a device tree
967 binary in its image. This device tree file should be in the
968 board directory and called <soc>-<board>.dts. The binary file
969 is then picked up in board_init_f() and made available through
970 the global data structure as gd->blob.
973 If this variable is defined, U-Boot will build a device tree
974 binary. It will be called u-boot.dtb. Architecture-specific
975 code will locate it at run-time. Generally this works by:
977 cat u-boot.bin u-boot.dtb >image.bin
979 and in fact, U-Boot does this for you, creating a file called
980 u-boot-dtb.bin which is useful in the common case. You can
981 still use the individual files if you need something more
986 If this variable is defined, it enables watchdog
987 support for the SoC. There must be support in the SoC
988 specific code for a watchdog. For the 8xx and 8260
989 CPUs, the SIU Watchdog feature is enabled in the SYPCR
990 register. When supported for a specific SoC is
991 available, then no further board specific code should
995 When using a watchdog circuitry external to the used
996 SoC, then define this variable and provide board
997 specific code for the "hw_watchdog_reset" function.
1000 CONFIG_VERSION_VARIABLE
1001 If this variable is defined, an environment variable
1002 named "ver" is created by U-Boot showing the U-Boot
1003 version as printed by the "version" command.
1004 Any change to this variable will be reverted at the
1009 When CONFIG_CMD_DATE is selected, the type of the RTC
1010 has to be selected, too. Define exactly one of the
1013 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1014 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1015 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1016 CONFIG_RTC_MC146818 - use MC146818 RTC
1017 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1018 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1019 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1020 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1021 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1022 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1023 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1024 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1027 Note that if the RTC uses I2C, then the I2C interface
1028 must also be configured. See I2C Support, below.
1031 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1032 CONFIG_PCA953X_INFO - enable pca953x info command
1034 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1035 chip-ngpio pairs that tell the PCA953X driver the number of
1036 pins supported by a particular chip.
1038 Note that if the GPIO device uses I2C, then the I2C interface
1039 must also be configured. See I2C Support, below.
1041 - Timestamp Support:
1043 When CONFIG_TIMESTAMP is selected, the timestamp
1044 (date and time) of an image is printed by image
1045 commands like bootm or iminfo. This option is
1046 automatically enabled when you select CONFIG_CMD_DATE .
1048 - Partition Labels (disklabels) Supported:
1049 Zero or more of the following:
1050 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1051 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1052 Intel architecture, USB sticks, etc.
1053 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1054 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1055 bootloader. Note 2TB partition limit; see
1057 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1059 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1060 CONFIG_CMD_SCSI) you must configure support for at
1061 least one non-MTD partition type as well.
1064 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1065 board configurations files but used nowhere!
1067 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1068 be performed by calling the function
1069 ide_set_reset(int reset)
1070 which has to be defined in a board specific file
1075 Set this to enable ATAPI support.
1080 Set this to enable support for disks larger than 137GB
1081 Also look at CONFIG_SYS_64BIT_LBA.
1082 Whithout these , LBA48 support uses 32bit variables and will 'only'
1083 support disks up to 2.1TB.
1085 CONFIG_SYS_64BIT_LBA:
1086 When enabled, makes the IDE subsystem use 64bit sector addresses.
1090 At the moment only there is only support for the
1091 SYM53C8XX SCSI controller; define
1092 CONFIG_SCSI_SYM53C8XX to enable it.
1094 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1095 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1096 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1097 maximum numbers of LUNs, SCSI ID's and target
1099 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1101 The environment variable 'scsidevs' is set to the number of
1102 SCSI devices found during the last scan.
1104 - NETWORK Support (PCI):
1106 Support for Intel 8254x/8257x gigabit chips.
1109 Utility code for direct access to the SPI bus on Intel 8257x.
1110 This does not do anything useful unless you set at least one
1111 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1113 CONFIG_E1000_SPI_GENERIC
1114 Allow generic access to the SPI bus on the Intel 8257x, for
1115 example with the "sspi" command.
1118 Management command for E1000 devices. When used on devices
1119 with SPI support you can reprogram the EEPROM from U-Boot.
1121 CONFIG_E1000_FALLBACK_MAC
1122 default MAC for empty EEPROM after production.
1125 Support for Intel 82557/82559/82559ER chips.
1126 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1127 write routine for first time initialisation.
1130 Support for Digital 2114x chips.
1131 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1132 modem chip initialisation (KS8761/QS6611).
1135 Support for National dp83815 chips.
1138 Support for National dp8382[01] gigabit chips.
1140 - NETWORK Support (other):
1142 CONFIG_DRIVER_AT91EMAC
1143 Support for AT91RM9200 EMAC.
1146 Define this to use reduced MII inteface
1148 CONFIG_DRIVER_AT91EMAC_QUIET
1149 If this defined, the driver is quiet.
1150 The driver doen't show link status messages.
1152 CONFIG_CALXEDA_XGMAC
1153 Support for the Calxeda XGMAC device
1156 Support for SMSC's LAN91C96 chips.
1158 CONFIG_LAN91C96_BASE
1159 Define this to hold the physical address
1160 of the LAN91C96's I/O space
1162 CONFIG_LAN91C96_USE_32_BIT
1163 Define this to enable 32 bit addressing
1166 Support for SMSC's LAN91C111 chip
1168 CONFIG_SMC91111_BASE
1169 Define this to hold the physical address
1170 of the device (I/O space)
1172 CONFIG_SMC_USE_32_BIT
1173 Define this if data bus is 32 bits
1175 CONFIG_SMC_USE_IOFUNCS
1176 Define this to use i/o functions instead of macros
1177 (some hardware wont work with macros)
1179 CONFIG_DRIVER_TI_EMAC
1180 Support for davinci emac
1182 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1183 Define this if you have more then 3 PHYs.
1186 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1188 CONFIG_FTGMAC100_EGIGA
1189 Define this to use GE link update with gigabit PHY.
1190 Define this if FTGMAC100 is connected to gigabit PHY.
1191 If your system has 10/100 PHY only, it might not occur
1192 wrong behavior. Because PHY usually return timeout or
1193 useless data when polling gigabit status and gigabit
1194 control registers. This behavior won't affect the
1195 correctnessof 10/100 link speed update.
1198 Support for SMSC's LAN911x and LAN921x chips
1201 Define this to hold the physical address
1202 of the device (I/O space)
1204 CONFIG_SMC911X_32_BIT
1205 Define this if data bus is 32 bits
1207 CONFIG_SMC911X_16_BIT
1208 Define this if data bus is 16 bits. If your processor
1209 automatically converts one 32 bit word to two 16 bit
1210 words you may also try CONFIG_SMC911X_32_BIT.
1213 Support for Renesas on-chip Ethernet controller
1215 CONFIG_SH_ETHER_USE_PORT
1216 Define the number of ports to be used
1218 CONFIG_SH_ETHER_PHY_ADDR
1219 Define the ETH PHY's address
1221 CONFIG_SH_ETHER_CACHE_WRITEBACK
1222 If this option is set, the driver enables cache flush.
1226 Support TPM devices.
1229 Support for i2c bus TPM devices. Only one device
1230 per system is supported at this time.
1232 CONFIG_TPM_TIS_I2C_BUS_NUMBER
1233 Define the the i2c bus number for the TPM device
1235 CONFIG_TPM_TIS_I2C_SLAVE_ADDRESS
1236 Define the TPM's address on the i2c bus
1238 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1239 Define the burst count bytes upper limit
1241 CONFIG_TPM_ATMEL_TWI
1242 Support for Atmel TWI TPM device. Requires I2C support.
1245 Support for generic parallel port TPM devices. Only one device
1246 per system is supported at this time.
1248 CONFIG_TPM_TIS_BASE_ADDRESS
1249 Base address where the generic TPM device is mapped
1250 to. Contemporary x86 systems usually map it at
1254 Add tpm monitor functions.
1255 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1256 provides monitor access to authorized functions.
1259 Define this to enable the TPM support library which provides
1260 functional interfaces to some TPM commands.
1261 Requires support for a TPM device.
1263 CONFIG_TPM_AUTH_SESSIONS
1264 Define this to enable authorized functions in the TPM library.
1265 Requires CONFIG_TPM and CONFIG_SHA1.
1268 At the moment only the UHCI host controller is
1269 supported (PIP405, MIP405, MPC5200); define
1270 CONFIG_USB_UHCI to enable it.
1271 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1272 and define CONFIG_USB_STORAGE to enable the USB
1275 Supported are USB Keyboards and USB Floppy drives
1277 MPC5200 USB requires additional defines:
1279 for 528 MHz Clock: 0x0001bbbb
1283 for differential drivers: 0x00001000
1284 for single ended drivers: 0x00005000
1285 for differential drivers on PSC3: 0x00000100
1286 for single ended drivers on PSC3: 0x00004100
1287 CONFIG_SYS_USB_EVENT_POLL
1288 May be defined to allow interrupt polling
1289 instead of using asynchronous interrupts
1291 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1292 txfilltuning field in the EHCI controller on reset.
1294 CONFIG_USB_HUB_MIN_POWER_ON_DELAY defines the minimum
1295 interval for usb hub power-on delay.(minimum 100msec)
1298 Define the below if you wish to use the USB console.
1299 Once firmware is rebuilt from a serial console issue the
1300 command "setenv stdin usbtty; setenv stdout usbtty" and
1301 attach your USB cable. The Unix command "dmesg" should print
1302 it has found a new device. The environment variable usbtty
1303 can be set to gserial or cdc_acm to enable your device to
1304 appear to a USB host as a Linux gserial device or a
1305 Common Device Class Abstract Control Model serial device.
1306 If you select usbtty = gserial you should be able to enumerate
1308 # modprobe usbserial vendor=0xVendorID product=0xProductID
1309 else if using cdc_acm, simply setting the environment
1310 variable usbtty to be cdc_acm should suffice. The following
1311 might be defined in YourBoardName.h
1314 Define this to build a UDC device
1317 Define this to have a tty type of device available to
1318 talk to the UDC device
1321 Define this to enable the high speed support for usb
1322 device and usbtty. If this feature is enabled, a routine
1323 int is_usbd_high_speed(void)
1324 also needs to be defined by the driver to dynamically poll
1325 whether the enumeration has succeded at high speed or full
1328 CONFIG_SYS_CONSOLE_IS_IN_ENV
1329 Define this if you want stdin, stdout &/or stderr to
1333 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1334 Derive USB clock from external clock "blah"
1335 - CONFIG_SYS_USB_EXTC_CLK 0x02
1337 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1338 Derive USB clock from brgclk
1339 - CONFIG_SYS_USB_BRG_CLK 0x04
1341 If you have a USB-IF assigned VendorID then you may wish to
1342 define your own vendor specific values either in BoardName.h
1343 or directly in usbd_vendor_info.h. If you don't define
1344 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1345 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1346 should pretend to be a Linux device to it's target host.
1348 CONFIG_USBD_MANUFACTURER
1349 Define this string as the name of your company for
1350 - CONFIG_USBD_MANUFACTURER "my company"
1352 CONFIG_USBD_PRODUCT_NAME
1353 Define this string as the name of your product
1354 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1356 CONFIG_USBD_VENDORID
1357 Define this as your assigned Vendor ID from the USB
1358 Implementors Forum. This *must* be a genuine Vendor ID
1359 to avoid polluting the USB namespace.
1360 - CONFIG_USBD_VENDORID 0xFFFF
1362 CONFIG_USBD_PRODUCTID
1363 Define this as the unique Product ID
1365 - CONFIG_USBD_PRODUCTID 0xFFFF
1367 - ULPI Layer Support:
1368 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1369 the generic ULPI layer. The generic layer accesses the ULPI PHY
1370 via the platform viewport, so you need both the genric layer and
1371 the viewport enabled. Currently only Chipidea/ARC based
1372 viewport is supported.
1373 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1374 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1375 If your ULPI phy needs a different reference clock than the
1376 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1377 the appropriate value in Hz.
1380 The MMC controller on the Intel PXA is supported. To
1381 enable this define CONFIG_MMC. The MMC can be
1382 accessed from the boot prompt by mapping the device
1383 to physical memory similar to flash. Command line is
1384 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1385 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1388 Support for Renesas on-chip MMCIF controller
1390 CONFIG_SH_MMCIF_ADDR
1391 Define the base address of MMCIF registers
1394 Define the clock frequency for MMCIF
1396 - USB Device Firmware Update (DFU) class support:
1398 This enables the USB portion of the DFU USB class
1401 This enables the command "dfu" which is used to have
1402 U-Boot create a DFU class device via USB. This command
1403 requires that the "dfu_alt_info" environment variable be
1404 set and define the alt settings to expose to the host.
1407 This enables support for exposing (e)MMC devices via DFU.
1410 This enables support for exposing NAND devices via DFU.
1412 CONFIG_SYS_DFU_DATA_BUF_SIZE
1413 Dfu transfer uses a buffer before writing data to the
1414 raw storage device. Make the size (in bytes) of this buffer
1415 configurable. The size of this buffer is also configurable
1416 through the "dfu_bufsiz" environment variable.
1418 CONFIG_SYS_DFU_MAX_FILE_SIZE
1419 When updating files rather than the raw storage device,
1420 we use a static buffer to copy the file into and then write
1421 the buffer once we've been given the whole file. Define
1422 this to the maximum filesize (in bytes) for the buffer.
1423 Default is 4 MiB if undefined.
1425 - Journaling Flash filesystem support:
1426 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1427 CONFIG_JFFS2_NAND_DEV
1428 Define these for a default partition on a NAND device
1430 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1431 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1432 Define these for a default partition on a NOR device
1434 CONFIG_SYS_JFFS_CUSTOM_PART
1435 Define this to create an own partition. You have to provide a
1436 function struct part_info* jffs2_part_info(int part_num)
1438 If you define only one JFFS2 partition you may also want to
1439 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1440 to disable the command chpart. This is the default when you
1441 have not defined a custom partition
1443 - FAT(File Allocation Table) filesystem write function support:
1446 Define this to enable support for saving memory data as a
1447 file in FAT formatted partition.
1449 This will also enable the command "fatwrite" enabling the
1450 user to write files to FAT.
1452 CBFS (Coreboot Filesystem) support
1455 Define this to enable support for reading from a Coreboot
1456 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1462 Define this to enable standard (PC-Style) keyboard
1466 Standard PC keyboard driver with US (is default) and
1467 GERMAN key layout (switch via environment 'keymap=de') support.
1468 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1469 for cfb_console. Supports cursor blinking.
1472 Enables a Chrome OS keyboard using the CROS_EC interface.
1473 This uses CROS_EC to communicate with a second microcontroller
1474 which provides key scans on request.
1479 Define this to enable video support (for output to
1482 CONFIG_VIDEO_CT69000
1484 Enable Chips & Technologies 69000 Video chip
1486 CONFIG_VIDEO_SMI_LYNXEM
1487 Enable Silicon Motion SMI 712/710/810 Video chip. The
1488 video output is selected via environment 'videoout'
1489 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1492 For the CT69000 and SMI_LYNXEM drivers, videomode is
1493 selected via environment 'videomode'. Two different ways
1495 - "videomode=num" 'num' is a standard LiLo mode numbers.
1496 Following standard modes are supported (* is default):
1498 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1499 -------------+---------------------------------------------
1500 8 bits | 0x301* 0x303 0x305 0x161 0x307
1501 15 bits | 0x310 0x313 0x316 0x162 0x319
1502 16 bits | 0x311 0x314 0x317 0x163 0x31A
1503 24 bits | 0x312 0x315 0x318 ? 0x31B
1504 -------------+---------------------------------------------
1505 (i.e. setenv videomode 317; saveenv; reset;)
1507 - "videomode=bootargs" all the video parameters are parsed
1508 from the bootargs. (See drivers/video/videomodes.c)
1511 CONFIG_VIDEO_SED13806
1512 Enable Epson SED13806 driver. This driver supports 8bpp
1513 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1514 or CONFIG_VIDEO_SED13806_16BPP
1517 Enable the Freescale DIU video driver. Reference boards for
1518 SOCs that have a DIU should define this macro to enable DIU
1519 support, and should also define these other macros:
1525 CONFIG_VIDEO_SW_CURSOR
1526 CONFIG_VGA_AS_SINGLE_DEVICE
1528 CONFIG_VIDEO_BMP_LOGO
1530 The DIU driver will look for the 'video-mode' environment
1531 variable, and if defined, enable the DIU as a console during
1532 boot. See the documentation file README.video for a
1533 description of this variable.
1537 Enable the VGA video / BIOS for x86. The alternative if you
1538 are using coreboot is to use the coreboot frame buffer
1545 Define this to enable a custom keyboard support.
1546 This simply calls drv_keyboard_init() which must be
1547 defined in your board-specific files.
1548 The only board using this so far is RBC823.
1550 - LCD Support: CONFIG_LCD
1552 Define this to enable LCD support (for output to LCD
1553 display); also select one of the supported displays
1554 by defining one of these:
1558 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1560 CONFIG_NEC_NL6448AC33:
1562 NEC NL6448AC33-18. Active, color, single scan.
1564 CONFIG_NEC_NL6448BC20
1566 NEC NL6448BC20-08. 6.5", 640x480.
1567 Active, color, single scan.
1569 CONFIG_NEC_NL6448BC33_54
1571 NEC NL6448BC33-54. 10.4", 640x480.
1572 Active, color, single scan.
1576 Sharp 320x240. Active, color, single scan.
1577 It isn't 16x9, and I am not sure what it is.
1579 CONFIG_SHARP_LQ64D341
1581 Sharp LQ64D341 display, 640x480.
1582 Active, color, single scan.
1586 HLD1045 display, 640x480.
1587 Active, color, single scan.
1591 Optrex CBL50840-2 NF-FW 99 22 M5
1593 Hitachi LMG6912RPFC-00T
1597 320x240. Black & white.
1599 Normally display is black on white background; define
1600 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1602 CONFIG_LCD_ALIGNMENT
1604 Normally the LCD is page-aligned (tyically 4KB). If this is
1605 defined then the LCD will be aligned to this value instead.
1606 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1607 here, since it is cheaper to change data cache settings on
1608 a per-section basis.
1610 CONFIG_CONSOLE_SCROLL_LINES
1612 When the console need to be scrolled, this is the number of
1613 lines to scroll by. It defaults to 1. Increasing this makes
1614 the console jump but can help speed up operation when scrolling
1619 Support drawing of RLE8-compressed bitmaps on the LCD.
1623 Enables an 'i2c edid' command which can read EDID
1624 information over I2C from an attached LCD display.
1626 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1628 If this option is set, the environment is checked for
1629 a variable "splashimage". If found, the usual display
1630 of logo, copyright and system information on the LCD
1631 is suppressed and the BMP image at the address
1632 specified in "splashimage" is loaded instead. The
1633 console is redirected to the "nulldev", too. This
1634 allows for a "silent" boot where a splash screen is
1635 loaded very quickly after power-on.
1637 CONFIG_SPLASHIMAGE_GUARD
1639 If this option is set, then U-Boot will prevent the environment
1640 variable "splashimage" from being set to a problematic address
1641 (see README.displaying-bmps and README.arm-unaligned-accesses).
1642 This option is useful for targets where, due to alignment
1643 restrictions, an improperly aligned BMP image will cause a data
1644 abort. If you think you will not have problems with unaligned
1645 accesses (for example because your toolchain prevents them)
1646 there is no need to set this option.
1648 CONFIG_SPLASH_SCREEN_ALIGN
1650 If this option is set the splash image can be freely positioned
1651 on the screen. Environment variable "splashpos" specifies the
1652 position as "x,y". If a positive number is given it is used as
1653 number of pixel from left/top. If a negative number is given it
1654 is used as number of pixel from right/bottom. You can also
1655 specify 'm' for centering the image.
1658 setenv splashpos m,m
1659 => image at center of screen
1661 setenv splashpos 30,20
1662 => image at x = 30 and y = 20
1664 setenv splashpos -10,m
1665 => vertically centered image
1666 at x = dspWidth - bmpWidth - 9
1668 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1670 If this option is set, additionally to standard BMP
1671 images, gzipped BMP images can be displayed via the
1672 splashscreen support or the bmp command.
1674 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1676 If this option is set, 8-bit RLE compressed BMP images
1677 can be displayed via the splashscreen support or the
1680 - Do compresssing for memory range:
1683 If this option is set, it would use zlib deflate method
1684 to compress the specified memory at its best effort.
1686 - Compression support:
1689 If this option is set, support for bzip2 compressed
1690 images is included. If not, only uncompressed and gzip
1691 compressed images are supported.
1693 NOTE: the bzip2 algorithm requires a lot of RAM, so
1694 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1699 If this option is set, support for lzma compressed
1702 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1703 requires an amount of dynamic memory that is given by the
1706 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1708 Where lc and lp stand for, respectively, Literal context bits
1709 and Literal pos bits.
1711 This value is upper-bounded by 14MB in the worst case. Anyway,
1712 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1713 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1714 a very small buffer.
1716 Use the lzmainfo tool to determinate the lc and lp values and
1717 then calculate the amount of needed dynamic memory (ensuring
1718 the appropriate CONFIG_SYS_MALLOC_LEN value).
1723 The address of PHY on MII bus.
1725 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1727 The clock frequency of the MII bus
1731 If this option is set, support for speed/duplex
1732 detection of gigabit PHY is included.
1734 CONFIG_PHY_RESET_DELAY
1736 Some PHY like Intel LXT971A need extra delay after
1737 reset before any MII register access is possible.
1738 For such PHY, set this option to the usec delay
1739 required. (minimum 300usec for LXT971A)
1741 CONFIG_PHY_CMD_DELAY (ppc4xx)
1743 Some PHY like Intel LXT971A need extra delay after
1744 command issued before MII status register can be read
1754 Define a default value for Ethernet address to use
1755 for the respective Ethernet interface, in case this
1756 is not determined automatically.
1761 Define a default value for the IP address to use for
1762 the default Ethernet interface, in case this is not
1763 determined through e.g. bootp.
1764 (Environment variable "ipaddr")
1766 - Server IP address:
1769 Defines a default value for the IP address of a TFTP
1770 server to contact when using the "tftboot" command.
1771 (Environment variable "serverip")
1773 CONFIG_KEEP_SERVERADDR
1775 Keeps the server's MAC address, in the env 'serveraddr'
1776 for passing to bootargs (like Linux's netconsole option)
1778 - Gateway IP address:
1781 Defines a default value for the IP address of the
1782 default router where packets to other networks are
1784 (Environment variable "gatewayip")
1789 Defines a default value for the subnet mask (or
1790 routing prefix) which is used to determine if an IP
1791 address belongs to the local subnet or needs to be
1792 forwarded through a router.
1793 (Environment variable "netmask")
1795 - Multicast TFTP Mode:
1798 Defines whether you want to support multicast TFTP as per
1799 rfc-2090; for example to work with atftp. Lets lots of targets
1800 tftp down the same boot image concurrently. Note: the Ethernet
1801 driver in use must provide a function: mcast() to join/leave a
1804 - BOOTP Recovery Mode:
1805 CONFIG_BOOTP_RANDOM_DELAY
1807 If you have many targets in a network that try to
1808 boot using BOOTP, you may want to avoid that all
1809 systems send out BOOTP requests at precisely the same
1810 moment (which would happen for instance at recovery
1811 from a power failure, when all systems will try to
1812 boot, thus flooding the BOOTP server. Defining
1813 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1814 inserted before sending out BOOTP requests. The
1815 following delays are inserted then:
1817 1st BOOTP request: delay 0 ... 1 sec
1818 2nd BOOTP request: delay 0 ... 2 sec
1819 3rd BOOTP request: delay 0 ... 4 sec
1821 BOOTP requests: delay 0 ... 8 sec
1823 - DHCP Advanced Options:
1824 You can fine tune the DHCP functionality by defining
1825 CONFIG_BOOTP_* symbols:
1827 CONFIG_BOOTP_SUBNETMASK
1828 CONFIG_BOOTP_GATEWAY
1829 CONFIG_BOOTP_HOSTNAME
1830 CONFIG_BOOTP_NISDOMAIN
1831 CONFIG_BOOTP_BOOTPATH
1832 CONFIG_BOOTP_BOOTFILESIZE
1835 CONFIG_BOOTP_SEND_HOSTNAME
1836 CONFIG_BOOTP_NTPSERVER
1837 CONFIG_BOOTP_TIMEOFFSET
1838 CONFIG_BOOTP_VENDOREX
1839 CONFIG_BOOTP_MAY_FAIL
1841 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1842 environment variable, not the BOOTP server.
1844 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1845 after the configured retry count, the call will fail
1846 instead of starting over. This can be used to fail over
1847 to Link-local IP address configuration if the DHCP server
1850 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1851 serverip from a DHCP server, it is possible that more
1852 than one DNS serverip is offered to the client.
1853 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1854 serverip will be stored in the additional environment
1855 variable "dnsip2". The first DNS serverip is always
1856 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1859 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1860 to do a dynamic update of a DNS server. To do this, they
1861 need the hostname of the DHCP requester.
1862 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1863 of the "hostname" environment variable is passed as
1864 option 12 to the DHCP server.
1866 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1868 A 32bit value in microseconds for a delay between
1869 receiving a "DHCP Offer" and sending the "DHCP Request".
1870 This fixes a problem with certain DHCP servers that don't
1871 respond 100% of the time to a "DHCP request". E.g. On an
1872 AT91RM9200 processor running at 180MHz, this delay needed
1873 to be *at least* 15,000 usec before a Windows Server 2003
1874 DHCP server would reply 100% of the time. I recommend at
1875 least 50,000 usec to be safe. The alternative is to hope
1876 that one of the retries will be successful but note that
1877 the DHCP timeout and retry process takes a longer than
1880 - Link-local IP address negotiation:
1881 Negotiate with other link-local clients on the local network
1882 for an address that doesn't require explicit configuration.
1883 This is especially useful if a DHCP server cannot be guaranteed
1884 to exist in all environments that the device must operate.
1886 See doc/README.link-local for more information.
1889 CONFIG_CDP_DEVICE_ID
1891 The device id used in CDP trigger frames.
1893 CONFIG_CDP_DEVICE_ID_PREFIX
1895 A two character string which is prefixed to the MAC address
1900 A printf format string which contains the ascii name of
1901 the port. Normally is set to "eth%d" which sets
1902 eth0 for the first Ethernet, eth1 for the second etc.
1904 CONFIG_CDP_CAPABILITIES
1906 A 32bit integer which indicates the device capabilities;
1907 0x00000010 for a normal host which does not forwards.
1911 An ascii string containing the version of the software.
1915 An ascii string containing the name of the platform.
1919 A 32bit integer sent on the trigger.
1921 CONFIG_CDP_POWER_CONSUMPTION
1923 A 16bit integer containing the power consumption of the
1924 device in .1 of milliwatts.
1926 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1928 A byte containing the id of the VLAN.
1930 - Status LED: CONFIG_STATUS_LED
1932 Several configurations allow to display the current
1933 status using a LED. For instance, the LED will blink
1934 fast while running U-Boot code, stop blinking as
1935 soon as a reply to a BOOTP request was received, and
1936 start blinking slow once the Linux kernel is running
1937 (supported by a status LED driver in the Linux
1938 kernel). Defining CONFIG_STATUS_LED enables this
1941 - CAN Support: CONFIG_CAN_DRIVER
1943 Defining CONFIG_CAN_DRIVER enables CAN driver support
1944 on those systems that support this (optional)
1945 feature, like the TQM8xxL modules.
1947 - I2C Support: CONFIG_SYS_I2C
1949 This enable the NEW i2c subsystem, and will allow you to use
1950 i2c commands at the u-boot command line (as long as you set
1951 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1952 based realtime clock chips or other i2c devices. See
1953 common/cmd_i2c.c for a description of the command line
1956 ported i2c driver to the new framework:
1957 - drivers/i2c/soft_i2c.c:
1958 - activate first bus with CONFIG_SYS_I2C_SOFT define
1959 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1960 for defining speed and slave address
1961 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1962 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1963 for defining speed and slave address
1964 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1965 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1966 for defining speed and slave address
1967 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1968 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1969 for defining speed and slave address
1973 CONFIG_SYS_NUM_I2C_BUSES
1974 Hold the number of i2c busses you want to use. If you
1975 don't use/have i2c muxes on your i2c bus, this
1976 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
1979 CONFIG_SYS_I2C_DIRECT_BUS
1980 define this, if you don't use i2c muxes on your hardware.
1981 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1984 CONFIG_SYS_I2C_MAX_HOPS
1985 define how many muxes are maximal consecutively connected
1986 on one i2c bus. If you not use i2c muxes, omit this
1989 CONFIG_SYS_I2C_BUSES
1990 hold a list of busses you want to use, only used if
1991 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1992 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1993 CONFIG_SYS_NUM_I2C_BUSES = 9:
1995 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1996 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1997 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1998 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1999 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2000 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2001 {1, {I2C_NULL_HOP}}, \
2002 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2003 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2007 bus 0 on adapter 0 without a mux
2008 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2009 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2010 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2011 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2012 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2013 bus 6 on adapter 1 without a mux
2014 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2015 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2017 If you do not have i2c muxes on your board, omit this define.
2019 - Legacy I2C Support: CONFIG_HARD_I2C
2021 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2022 provides the following compelling advantages:
2024 - more than one i2c adapter is usable
2025 - approved multibus support
2026 - better i2c mux support
2028 ** Please consider updating your I2C driver now. **
2030 These enable legacy I2C serial bus commands. Defining
2031 CONFIG_HARD_I2C will include the appropriate I2C driver
2032 for the selected CPU.
2034 This will allow you to use i2c commands at the u-boot
2035 command line (as long as you set CONFIG_CMD_I2C in
2036 CONFIG_COMMANDS) and communicate with i2c based realtime
2037 clock chips. See common/cmd_i2c.c for a description of the
2038 command line interface.
2040 CONFIG_HARD_I2C selects a hardware I2C controller.
2042 There are several other quantities that must also be
2043 defined when you define CONFIG_HARD_I2C.
2045 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2046 to be the frequency (in Hz) at which you wish your i2c bus
2047 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2048 the CPU's i2c node address).
2050 Now, the u-boot i2c code for the mpc8xx
2051 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2052 and so its address should therefore be cleared to 0 (See,
2053 eg, MPC823e User's Manual p.16-473). So, set
2054 CONFIG_SYS_I2C_SLAVE to 0.
2056 CONFIG_SYS_I2C_INIT_MPC5XXX
2058 When a board is reset during an i2c bus transfer
2059 chips might think that the current transfer is still
2060 in progress. Reset the slave devices by sending start
2061 commands until the slave device responds.
2063 That's all that's required for CONFIG_HARD_I2C.
2065 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2066 then the following macros need to be defined (examples are
2067 from include/configs/lwmon.h):
2071 (Optional). Any commands necessary to enable the I2C
2072 controller or configure ports.
2074 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2078 (Only for MPC8260 CPU). The I/O port to use (the code
2079 assumes both bits are on the same port). Valid values
2080 are 0..3 for ports A..D.
2084 The code necessary to make the I2C data line active
2085 (driven). If the data line is open collector, this
2088 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2092 The code necessary to make the I2C data line tri-stated
2093 (inactive). If the data line is open collector, this
2096 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2100 Code that returns true if the I2C data line is high,
2103 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2107 If <bit> is true, sets the I2C data line high. If it
2108 is false, it clears it (low).
2110 eg: #define I2C_SDA(bit) \
2111 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2112 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2116 If <bit> is true, sets the I2C clock line high. If it
2117 is false, it clears it (low).
2119 eg: #define I2C_SCL(bit) \
2120 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2121 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2125 This delay is invoked four times per clock cycle so this
2126 controls the rate of data transfer. The data rate thus
2127 is 1 / (I2C_DELAY * 4). Often defined to be something
2130 #define I2C_DELAY udelay(2)
2132 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2134 If your arch supports the generic GPIO framework (asm/gpio.h),
2135 then you may alternatively define the two GPIOs that are to be
2136 used as SCL / SDA. Any of the previous I2C_xxx macros will
2137 have GPIO-based defaults assigned to them as appropriate.
2139 You should define these to the GPIO value as given directly to
2140 the generic GPIO functions.
2142 CONFIG_SYS_I2C_INIT_BOARD
2144 When a board is reset during an i2c bus transfer
2145 chips might think that the current transfer is still
2146 in progress. On some boards it is possible to access
2147 the i2c SCLK line directly, either by using the
2148 processor pin as a GPIO or by having a second pin
2149 connected to the bus. If this option is defined a
2150 custom i2c_init_board() routine in boards/xxx/board.c
2151 is run early in the boot sequence.
2153 CONFIG_SYS_I2C_BOARD_LATE_INIT
2155 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2156 defined a custom i2c_board_late_init() routine in
2157 boards/xxx/board.c is run AFTER the operations in i2c_init()
2158 is completed. This callpoint can be used to unreset i2c bus
2159 using CPU i2c controller register accesses for CPUs whose i2c
2160 controller provide such a method. It is called at the end of
2161 i2c_init() to allow i2c_init operations to setup the i2c bus
2162 controller on the CPU (e.g. setting bus speed & slave address).
2164 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2166 This option enables configuration of bi_iic_fast[] flags
2167 in u-boot bd_info structure based on u-boot environment
2168 variable "i2cfast". (see also i2cfast)
2170 CONFIG_I2C_MULTI_BUS
2172 This option allows the use of multiple I2C buses, each of which
2173 must have a controller. At any point in time, only one bus is
2174 active. To switch to a different bus, use the 'i2c dev' command.
2175 Note that bus numbering is zero-based.
2177 CONFIG_SYS_I2C_NOPROBES
2179 This option specifies a list of I2C devices that will be skipped
2180 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2181 is set, specify a list of bus-device pairs. Otherwise, specify
2182 a 1D array of device addresses
2185 #undef CONFIG_I2C_MULTI_BUS
2186 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2188 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2190 #define CONFIG_I2C_MULTI_BUS
2191 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2193 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2195 CONFIG_SYS_SPD_BUS_NUM
2197 If defined, then this indicates the I2C bus number for DDR SPD.
2198 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2200 CONFIG_SYS_RTC_BUS_NUM
2202 If defined, then this indicates the I2C bus number for the RTC.
2203 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2205 CONFIG_SYS_DTT_BUS_NUM
2207 If defined, then this indicates the I2C bus number for the DTT.
2208 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2210 CONFIG_SYS_I2C_DTT_ADDR:
2212 If defined, specifies the I2C address of the DTT device.
2213 If not defined, then U-Boot uses predefined value for
2214 specified DTT device.
2218 Define this option if you want to use Freescale's I2C driver in
2219 drivers/i2c/fsl_i2c.c.
2223 Define this option if you have I2C devices reached over 1 .. n
2224 I2C Muxes like the pca9544a. This option addes a new I2C
2225 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2226 new I2C Bus to the existing I2C Busses. If you select the
2227 new Bus with "i2c dev", u-bbot sends first the commandos for
2228 the muxes to activate this new "bus".
2230 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2234 Adding a new I2C Bus reached over 2 pca9544a muxes
2235 The First mux with address 70 and channel 6
2236 The Second mux with address 71 and channel 4
2238 => i2c bus pca9544a:70:6:pca9544a:71:4
2240 Use the "i2c bus" command without parameter, to get a list
2241 of I2C Busses with muxes:
2244 Busses reached over muxes:
2246 reached over Mux(es):
2249 reached over Mux(es):
2254 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2255 u-boot first sends the command to the mux@70 to enable
2256 channel 6, and then the command to the mux@71 to enable
2259 After that, you can use the "normal" i2c commands as
2260 usual to communicate with your I2C devices behind
2263 This option is actually implemented for the bitbanging
2264 algorithm in common/soft_i2c.c and for the Hardware I2C
2265 Bus on the MPC8260. But it should be not so difficult
2266 to add this option to other architectures.
2268 CONFIG_SOFT_I2C_READ_REPEATED_START
2270 defining this will force the i2c_read() function in
2271 the soft_i2c driver to perform an I2C repeated start
2272 between writing the address pointer and reading the
2273 data. If this define is omitted the default behaviour
2274 of doing a stop-start sequence will be used. Most I2C
2275 devices can use either method, but some require one or
2278 - SPI Support: CONFIG_SPI
2280 Enables SPI driver (so far only tested with
2281 SPI EEPROM, also an instance works with Crystal A/D and
2282 D/As on the SACSng board)
2286 Enables the driver for SPI controller on SuperH. Currently
2287 only SH7757 is supported.
2291 Enables extended (16-bit) SPI EEPROM addressing.
2292 (symmetrical to CONFIG_I2C_X)
2296 Enables a software (bit-bang) SPI driver rather than
2297 using hardware support. This is a general purpose
2298 driver that only requires three general I/O port pins
2299 (two outputs, one input) to function. If this is
2300 defined, the board configuration must define several
2301 SPI configuration items (port pins to use, etc). For
2302 an example, see include/configs/sacsng.h.
2306 Enables a hardware SPI driver for general-purpose reads
2307 and writes. As with CONFIG_SOFT_SPI, the board configuration
2308 must define a list of chip-select function pointers.
2309 Currently supported on some MPC8xxx processors. For an
2310 example, see include/configs/mpc8349emds.h.
2314 Enables the driver for the SPI controllers on i.MX and MXC
2315 SoCs. Currently i.MX31/35/51 are supported.
2317 - FPGA Support: CONFIG_FPGA
2319 Enables FPGA subsystem.
2321 CONFIG_FPGA_<vendor>
2323 Enables support for specific chip vendors.
2326 CONFIG_FPGA_<family>
2328 Enables support for FPGA family.
2329 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2333 Specify the number of FPGA devices to support.
2335 CONFIG_SYS_FPGA_PROG_FEEDBACK
2337 Enable printing of hash marks during FPGA configuration.
2339 CONFIG_SYS_FPGA_CHECK_BUSY
2341 Enable checks on FPGA configuration interface busy
2342 status by the configuration function. This option
2343 will require a board or device specific function to
2348 If defined, a function that provides delays in the FPGA
2349 configuration driver.
2351 CONFIG_SYS_FPGA_CHECK_CTRLC
2352 Allow Control-C to interrupt FPGA configuration
2354 CONFIG_SYS_FPGA_CHECK_ERROR
2356 Check for configuration errors during FPGA bitfile
2357 loading. For example, abort during Virtex II
2358 configuration if the INIT_B line goes low (which
2359 indicated a CRC error).
2361 CONFIG_SYS_FPGA_WAIT_INIT
2363 Maximum time to wait for the INIT_B line to deassert
2364 after PROB_B has been deasserted during a Virtex II
2365 FPGA configuration sequence. The default time is 500
2368 CONFIG_SYS_FPGA_WAIT_BUSY
2370 Maximum time to wait for BUSY to deassert during
2371 Virtex II FPGA configuration. The default is 5 ms.
2373 CONFIG_SYS_FPGA_WAIT_CONFIG
2375 Time to wait after FPGA configuration. The default is
2378 - Configuration Management:
2381 If defined, this string will be added to the U-Boot
2382 version information (U_BOOT_VERSION)
2384 - Vendor Parameter Protection:
2386 U-Boot considers the values of the environment
2387 variables "serial#" (Board Serial Number) and
2388 "ethaddr" (Ethernet Address) to be parameters that
2389 are set once by the board vendor / manufacturer, and
2390 protects these variables from casual modification by
2391 the user. Once set, these variables are read-only,
2392 and write or delete attempts are rejected. You can
2393 change this behaviour:
2395 If CONFIG_ENV_OVERWRITE is #defined in your config
2396 file, the write protection for vendor parameters is
2397 completely disabled. Anybody can change or delete
2400 Alternatively, if you #define _both_ CONFIG_ETHADDR
2401 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2402 Ethernet address is installed in the environment,
2403 which can be changed exactly ONCE by the user. [The
2404 serial# is unaffected by this, i. e. it remains
2407 The same can be accomplished in a more flexible way
2408 for any variable by configuring the type of access
2409 to allow for those variables in the ".flags" variable
2410 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2415 Define this variable to enable the reservation of
2416 "protected RAM", i. e. RAM which is not overwritten
2417 by U-Boot. Define CONFIG_PRAM to hold the number of
2418 kB you want to reserve for pRAM. You can overwrite
2419 this default value by defining an environment
2420 variable "pram" to the number of kB you want to
2421 reserve. Note that the board info structure will
2422 still show the full amount of RAM. If pRAM is
2423 reserved, a new environment variable "mem" will
2424 automatically be defined to hold the amount of
2425 remaining RAM in a form that can be passed as boot
2426 argument to Linux, for instance like that:
2428 setenv bootargs ... mem=\${mem}
2431 This way you can tell Linux not to use this memory,
2432 either, which results in a memory region that will
2433 not be affected by reboots.
2435 *WARNING* If your board configuration uses automatic
2436 detection of the RAM size, you must make sure that
2437 this memory test is non-destructive. So far, the
2438 following board configurations are known to be
2441 IVMS8, IVML24, SPD8xx, TQM8xxL,
2442 HERMES, IP860, RPXlite, LWMON,
2445 - Access to physical memory region (> 4GB)
2446 Some basic support is provided for operations on memory not
2447 normally accessible to U-Boot - e.g. some architectures
2448 support access to more than 4GB of memory on 32-bit
2449 machines using physical address extension or similar.
2450 Define CONFIG_PHYSMEM to access this basic support, which
2451 currently only supports clearing the memory.
2456 Define this variable to stop the system in case of a
2457 fatal error, so that you have to reset it manually.
2458 This is probably NOT a good idea for an embedded
2459 system where you want the system to reboot
2460 automatically as fast as possible, but it may be
2461 useful during development since you can try to debug
2462 the conditions that lead to the situation.
2464 CONFIG_NET_RETRY_COUNT
2466 This variable defines the number of retries for
2467 network operations like ARP, RARP, TFTP, or BOOTP
2468 before giving up the operation. If not defined, a
2469 default value of 5 is used.
2473 Timeout waiting for an ARP reply in milliseconds.
2477 Timeout in milliseconds used in NFS protocol.
2478 If you encounter "ERROR: Cannot umount" in nfs command,
2479 try longer timeout such as
2480 #define CONFIG_NFS_TIMEOUT 10000UL
2482 - Command Interpreter:
2483 CONFIG_AUTO_COMPLETE
2485 Enable auto completion of commands using TAB.
2487 Note that this feature has NOT been implemented yet
2488 for the "hush" shell.
2491 CONFIG_SYS_HUSH_PARSER
2493 Define this variable to enable the "hush" shell (from
2494 Busybox) as command line interpreter, thus enabling
2495 powerful command line syntax like
2496 if...then...else...fi conditionals or `&&' and '||'
2497 constructs ("shell scripts").
2499 If undefined, you get the old, much simpler behaviour
2500 with a somewhat smaller memory footprint.
2503 CONFIG_SYS_PROMPT_HUSH_PS2
2505 This defines the secondary prompt string, which is
2506 printed when the command interpreter needs more input
2507 to complete a command. Usually "> ".
2511 In the current implementation, the local variables
2512 space and global environment variables space are
2513 separated. Local variables are those you define by
2514 simply typing `name=value'. To access a local
2515 variable later on, you have write `$name' or
2516 `${name}'; to execute the contents of a variable
2517 directly type `$name' at the command prompt.
2519 Global environment variables are those you use
2520 setenv/printenv to work with. To run a command stored
2521 in such a variable, you need to use the run command,
2522 and you must not use the '$' sign to access them.
2524 To store commands and special characters in a
2525 variable, please use double quotation marks
2526 surrounding the whole text of the variable, instead
2527 of the backslashes before semicolons and special
2530 - Commandline Editing and History:
2531 CONFIG_CMDLINE_EDITING
2533 Enable editing and History functions for interactive
2534 commandline input operations
2536 - Default Environment:
2537 CONFIG_EXTRA_ENV_SETTINGS
2539 Define this to contain any number of null terminated
2540 strings (variable = value pairs) that will be part of
2541 the default environment compiled into the boot image.
2543 For example, place something like this in your
2544 board's config file:
2546 #define CONFIG_EXTRA_ENV_SETTINGS \
2550 Warning: This method is based on knowledge about the
2551 internal format how the environment is stored by the
2552 U-Boot code. This is NOT an official, exported
2553 interface! Although it is unlikely that this format
2554 will change soon, there is no guarantee either.
2555 You better know what you are doing here.
2557 Note: overly (ab)use of the default environment is
2558 discouraged. Make sure to check other ways to preset
2559 the environment like the "source" command or the
2562 CONFIG_ENV_VARS_UBOOT_CONFIG
2564 Define this in order to add variables describing the
2565 U-Boot build configuration to the default environment.
2566 These will be named arch, cpu, board, vendor, and soc.
2568 Enabling this option will cause the following to be defined:
2576 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2578 Define this in order to add variables describing certain
2579 run-time determined information about the hardware to the
2580 environment. These will be named board_name, board_rev.
2582 CONFIG_DELAY_ENVIRONMENT
2584 Normally the environment is loaded when the board is
2585 intialised so that it is available to U-Boot. This inhibits
2586 that so that the environment is not available until
2587 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2588 this is instead controlled by the value of
2589 /config/load-environment.
2591 - DataFlash Support:
2592 CONFIG_HAS_DATAFLASH
2594 Defining this option enables DataFlash features and
2595 allows to read/write in Dataflash via the standard
2598 - Serial Flash support
2601 Defining this option enables SPI flash commands
2602 'sf probe/read/write/erase/update'.
2604 Usage requires an initial 'probe' to define the serial
2605 flash parameters, followed by read/write/erase/update
2608 The following defaults may be provided by the platform
2609 to handle the common case when only a single serial
2610 flash is present on the system.
2612 CONFIG_SF_DEFAULT_BUS Bus identifier
2613 CONFIG_SF_DEFAULT_CS Chip-select
2614 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2615 CONFIG_SF_DEFAULT_SPEED in Hz
2619 Define this option to include a destructive SPI flash
2622 CONFIG_SPI_FLASH_BAR Ban/Extended Addr Reg
2624 Define this option to use the Bank addr/Extended addr
2625 support on SPI flashes which has size > 16Mbytes.
2627 - SystemACE Support:
2630 Adding this option adds support for Xilinx SystemACE
2631 chips attached via some sort of local bus. The address
2632 of the chip must also be defined in the
2633 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2635 #define CONFIG_SYSTEMACE
2636 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2638 When SystemACE support is added, the "ace" device type
2639 becomes available to the fat commands, i.e. fatls.
2641 - TFTP Fixed UDP Port:
2644 If this is defined, the environment variable tftpsrcp
2645 is used to supply the TFTP UDP source port value.
2646 If tftpsrcp isn't defined, the normal pseudo-random port
2647 number generator is used.
2649 Also, the environment variable tftpdstp is used to supply
2650 the TFTP UDP destination port value. If tftpdstp isn't
2651 defined, the normal port 69 is used.
2653 The purpose for tftpsrcp is to allow a TFTP server to
2654 blindly start the TFTP transfer using the pre-configured
2655 target IP address and UDP port. This has the effect of
2656 "punching through" the (Windows XP) firewall, allowing
2657 the remainder of the TFTP transfer to proceed normally.
2658 A better solution is to properly configure the firewall,
2659 but sometimes that is not allowed.
2664 This enables a generic 'hash' command which can produce
2665 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2669 Enable the hash verify command (hash -v). This adds to code
2672 CONFIG_SHA1 - support SHA1 hashing
2673 CONFIG_SHA256 - support SHA256 hashing
2675 Note: There is also a sha1sum command, which should perhaps
2676 be deprecated in favour of 'hash sha1'.
2681 This enables the RSA algorithm used for FIT image verification
2682 in U-Boot. See doc/uImage/signature for more information.
2684 The signing part is build into mkimage regardless of this
2688 - Show boot progress:
2689 CONFIG_SHOW_BOOT_PROGRESS
2691 Defining this option allows to add some board-
2692 specific code (calling a user-provided function
2693 "show_boot_progress(int)") that enables you to show
2694 the system's boot progress on some display (for
2695 example, some LED's) on your board. At the moment,
2696 the following checkpoints are implemented:
2698 - Detailed boot stage timing
2700 Define this option to get detailed timing of each stage
2701 of the boot process.
2703 CONFIG_BOOTSTAGE_USER_COUNT
2704 This is the number of available user bootstage records.
2705 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2706 a new ID will be allocated from this stash. If you exceed
2707 the limit, recording will stop.
2709 CONFIG_BOOTSTAGE_REPORT
2710 Define this to print a report before boot, similar to this:
2712 Timer summary in microseconds:
2715 3,575,678 3,575,678 board_init_f start
2716 3,575,695 17 arch_cpu_init A9
2717 3,575,777 82 arch_cpu_init done
2718 3,659,598 83,821 board_init_r start
2719 3,910,375 250,777 main_loop
2720 29,916,167 26,005,792 bootm_start
2721 30,361,327 445,160 start_kernel
2723 CONFIG_CMD_BOOTSTAGE
2724 Add a 'bootstage' command which supports printing a report
2725 and un/stashing of bootstage data.
2727 CONFIG_BOOTSTAGE_FDT
2728 Stash the bootstage information in the FDT. A root 'bootstage'
2729 node is created with each bootstage id as a child. Each child
2730 has a 'name' property and either 'mark' containing the
2731 mark time in microsecond, or 'accum' containing the
2732 accumulated time for that bootstage id in microseconds.
2737 name = "board_init_f";
2746 Code in the Linux kernel can find this in /proc/devicetree.
2748 Legacy uImage format:
2751 1 common/cmd_bootm.c before attempting to boot an image
2752 -1 common/cmd_bootm.c Image header has bad magic number
2753 2 common/cmd_bootm.c Image header has correct magic number
2754 -2 common/cmd_bootm.c Image header has bad checksum
2755 3 common/cmd_bootm.c Image header has correct checksum
2756 -3 common/cmd_bootm.c Image data has bad checksum
2757 4 common/cmd_bootm.c Image data has correct checksum
2758 -4 common/cmd_bootm.c Image is for unsupported architecture
2759 5 common/cmd_bootm.c Architecture check OK
2760 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2761 6 common/cmd_bootm.c Image Type check OK
2762 -6 common/cmd_bootm.c gunzip uncompression error
2763 -7 common/cmd_bootm.c Unimplemented compression type
2764 7 common/cmd_bootm.c Uncompression OK
2765 8 common/cmd_bootm.c No uncompress/copy overwrite error
2766 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2768 9 common/image.c Start initial ramdisk verification
2769 -10 common/image.c Ramdisk header has bad magic number
2770 -11 common/image.c Ramdisk header has bad checksum
2771 10 common/image.c Ramdisk header is OK
2772 -12 common/image.c Ramdisk data has bad checksum
2773 11 common/image.c Ramdisk data has correct checksum
2774 12 common/image.c Ramdisk verification complete, start loading
2775 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2776 13 common/image.c Start multifile image verification
2777 14 common/image.c No initial ramdisk, no multifile, continue.
2779 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2781 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2782 -31 post/post.c POST test failed, detected by post_output_backlog()
2783 -32 post/post.c POST test failed, detected by post_run_single()
2785 34 common/cmd_doc.c before loading a Image from a DOC device
2786 -35 common/cmd_doc.c Bad usage of "doc" command
2787 35 common/cmd_doc.c correct usage of "doc" command
2788 -36 common/cmd_doc.c No boot device
2789 36 common/cmd_doc.c correct boot device
2790 -37 common/cmd_doc.c Unknown Chip ID on boot device
2791 37 common/cmd_doc.c correct chip ID found, device available
2792 -38 common/cmd_doc.c Read Error on boot device
2793 38 common/cmd_doc.c reading Image header from DOC device OK
2794 -39 common/cmd_doc.c Image header has bad magic number
2795 39 common/cmd_doc.c Image header has correct magic number
2796 -40 common/cmd_doc.c Error reading Image from DOC device
2797 40 common/cmd_doc.c Image header has correct magic number
2798 41 common/cmd_ide.c before loading a Image from a IDE device
2799 -42 common/cmd_ide.c Bad usage of "ide" command
2800 42 common/cmd_ide.c correct usage of "ide" command
2801 -43 common/cmd_ide.c No boot device
2802 43 common/cmd_ide.c boot device found
2803 -44 common/cmd_ide.c Device not available
2804 44 common/cmd_ide.c Device available
2805 -45 common/cmd_ide.c wrong partition selected
2806 45 common/cmd_ide.c partition selected
2807 -46 common/cmd_ide.c Unknown partition table
2808 46 common/cmd_ide.c valid partition table found
2809 -47 common/cmd_ide.c Invalid partition type
2810 47 common/cmd_ide.c correct partition type
2811 -48 common/cmd_ide.c Error reading Image Header on boot device
2812 48 common/cmd_ide.c reading Image Header from IDE device OK
2813 -49 common/cmd_ide.c Image header has bad magic number
2814 49 common/cmd_ide.c Image header has correct magic number
2815 -50 common/cmd_ide.c Image header has bad checksum
2816 50 common/cmd_ide.c Image header has correct checksum
2817 -51 common/cmd_ide.c Error reading Image from IDE device
2818 51 common/cmd_ide.c reading Image from IDE device OK
2819 52 common/cmd_nand.c before loading a Image from a NAND device
2820 -53 common/cmd_nand.c Bad usage of "nand" command
2821 53 common/cmd_nand.c correct usage of "nand" command
2822 -54 common/cmd_nand.c No boot device
2823 54 common/cmd_nand.c boot device found
2824 -55 common/cmd_nand.c Unknown Chip ID on boot device
2825 55 common/cmd_nand.c correct chip ID found, device available
2826 -56 common/cmd_nand.c Error reading Image Header on boot device
2827 56 common/cmd_nand.c reading Image Header from NAND device OK
2828 -57 common/cmd_nand.c Image header has bad magic number
2829 57 common/cmd_nand.c Image header has correct magic number
2830 -58 common/cmd_nand.c Error reading Image from NAND device
2831 58 common/cmd_nand.c reading Image from NAND device OK
2833 -60 common/env_common.c Environment has a bad CRC, using default
2835 64 net/eth.c starting with Ethernet configuration.
2836 -64 net/eth.c no Ethernet found.
2837 65 net/eth.c Ethernet found.
2839 -80 common/cmd_net.c usage wrong
2840 80 common/cmd_net.c before calling NetLoop()
2841 -81 common/cmd_net.c some error in NetLoop() occurred
2842 81 common/cmd_net.c NetLoop() back without error
2843 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2844 82 common/cmd_net.c trying automatic boot
2845 83 common/cmd_net.c running "source" command
2846 -83 common/cmd_net.c some error in automatic boot or "source" command
2847 84 common/cmd_net.c end without errors
2852 100 common/cmd_bootm.c Kernel FIT Image has correct format
2853 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2854 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2855 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2856 102 common/cmd_bootm.c Kernel unit name specified
2857 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2858 103 common/cmd_bootm.c Found configuration node
2859 104 common/cmd_bootm.c Got kernel subimage node offset
2860 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2861 105 common/cmd_bootm.c Kernel subimage hash verification OK
2862 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2863 106 common/cmd_bootm.c Architecture check OK
2864 -106 common/cmd_bootm.c Kernel subimage has wrong type
2865 107 common/cmd_bootm.c Kernel subimage type OK
2866 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2867 108 common/cmd_bootm.c Got kernel subimage data/size
2868 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2869 -109 common/cmd_bootm.c Can't get kernel subimage type
2870 -110 common/cmd_bootm.c Can't get kernel subimage comp
2871 -111 common/cmd_bootm.c Can't get kernel subimage os
2872 -112 common/cmd_bootm.c Can't get kernel subimage load address
2873 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2875 120 common/image.c Start initial ramdisk verification
2876 -120 common/image.c Ramdisk FIT image has incorrect format
2877 121 common/image.c Ramdisk FIT image has correct format
2878 122 common/image.c No ramdisk subimage unit name, using configuration
2879 -122 common/image.c Can't get configuration for ramdisk subimage
2880 123 common/image.c Ramdisk unit name specified
2881 -124 common/image.c Can't get ramdisk subimage node offset
2882 125 common/image.c Got ramdisk subimage node offset
2883 -125 common/image.c Ramdisk subimage hash verification failed
2884 126 common/image.c Ramdisk subimage hash verification OK
2885 -126 common/image.c Ramdisk subimage for unsupported architecture
2886 127 common/image.c Architecture check OK
2887 -127 common/image.c Can't get ramdisk subimage data/size
2888 128 common/image.c Got ramdisk subimage data/size
2889 129 common/image.c Can't get ramdisk load address
2890 -129 common/image.c Got ramdisk load address
2892 -130 common/cmd_doc.c Incorrect FIT image format
2893 131 common/cmd_doc.c FIT image format OK
2895 -140 common/cmd_ide.c Incorrect FIT image format
2896 141 common/cmd_ide.c FIT image format OK
2898 -150 common/cmd_nand.c Incorrect FIT image format
2899 151 common/cmd_nand.c FIT image format OK
2901 - FIT image support:
2903 Enable support for the FIT uImage format.
2905 CONFIG_FIT_BEST_MATCH
2906 When no configuration is explicitly selected, default to the
2907 one whose fdt's compatibility field best matches that of
2908 U-Boot itself. A match is considered "best" if it matches the
2909 most specific compatibility entry of U-Boot's fdt's root node.
2910 The order of entries in the configuration's fdt is ignored.
2912 CONFIG_FIT_SIGNATURE
2913 This option enables signature verification of FIT uImages,
2914 using a hash signed and verified using RSA. See
2915 doc/uImage.FIT/signature.txt for more details.
2917 - Standalone program support:
2918 CONFIG_STANDALONE_LOAD_ADDR
2920 This option defines a board specific value for the
2921 address where standalone program gets loaded, thus
2922 overwriting the architecture dependent default
2925 - Frame Buffer Address:
2928 Define CONFIG_FB_ADDR if you want to use specific
2929 address for frame buffer. This is typically the case
2930 when using a graphics controller has separate video
2931 memory. U-Boot will then place the frame buffer at
2932 the given address instead of dynamically reserving it
2933 in system RAM by calling lcd_setmem(), which grabs
2934 the memory for the frame buffer depending on the
2935 configured panel size.
2937 Please see board_init_f function.
2939 - Automatic software updates via TFTP server
2941 CONFIG_UPDATE_TFTP_CNT_MAX
2942 CONFIG_UPDATE_TFTP_MSEC_MAX
2944 These options enable and control the auto-update feature;
2945 for a more detailed description refer to doc/README.update.
2947 - MTD Support (mtdparts command, UBI support)
2950 Adds the MTD device infrastructure from the Linux kernel.
2951 Needed for mtdparts command support.
2953 CONFIG_MTD_PARTITIONS
2955 Adds the MTD partitioning infrastructure from the Linux
2956 kernel. Needed for UBI support.
2961 Adds commands for interacting with MTD partitions formatted
2962 with the UBI flash translation layer
2964 Requires also defining CONFIG_RBTREE
2966 CONFIG_UBI_SILENCE_MSG
2968 Make the verbose messages from UBI stop printing. This leaves
2969 warnings and errors enabled.
2974 Adds commands for interacting with UBI volumes formatted as
2975 UBIFS. UBIFS is read-only in u-boot.
2977 Requires UBI support as well as CONFIG_LZO
2979 CONFIG_UBIFS_SILENCE_MSG
2981 Make the verbose messages from UBIFS stop printing. This leaves
2982 warnings and errors enabled.
2986 Enable building of SPL globally.
2989 LDSCRIPT for linking the SPL binary.
2991 CONFIG_SPL_MAX_FOOTPRINT
2992 Maximum size in memory allocated to the SPL, BSS included.
2993 When defined, the linker checks that the actual memory
2994 used by SPL from _start to __bss_end does not exceed it.
2995 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2996 must not be both defined at the same time.
2999 Maximum size of the SPL image (text, data, rodata, and
3000 linker lists sections), BSS excluded.
3001 When defined, the linker checks that the actual size does
3004 CONFIG_SPL_TEXT_BASE
3005 TEXT_BASE for linking the SPL binary.
3007 CONFIG_SPL_RELOC_TEXT_BASE
3008 Address to relocate to. If unspecified, this is equal to
3009 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3011 CONFIG_SPL_BSS_START_ADDR
3012 Link address for the BSS within the SPL binary.
3014 CONFIG_SPL_BSS_MAX_SIZE
3015 Maximum size in memory allocated to the SPL BSS.
3016 When defined, the linker checks that the actual memory used
3017 by SPL from __bss_start to __bss_end does not exceed it.
3018 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3019 must not be both defined at the same time.
3022 Adress of the start of the stack SPL will use
3024 CONFIG_SPL_RELOC_STACK
3025 Adress of the start of the stack SPL will use after
3026 relocation. If unspecified, this is equal to
3029 CONFIG_SYS_SPL_MALLOC_START
3030 Starting address of the malloc pool used in SPL.
3032 CONFIG_SYS_SPL_MALLOC_SIZE
3033 The size of the malloc pool used in SPL.
3035 CONFIG_SPL_FRAMEWORK
3036 Enable the SPL framework under common/. This framework
3037 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3038 NAND loading of the Linux Kernel.
3040 CONFIG_SPL_DISPLAY_PRINT
3041 For ARM, enable an optional function to print more information
3042 about the running system.
3044 CONFIG_SPL_INIT_MINIMAL
3045 Arch init code should be built for a very small image
3047 CONFIG_SPL_LIBCOMMON_SUPPORT
3048 Support for common/libcommon.o in SPL binary
3050 CONFIG_SPL_LIBDISK_SUPPORT
3051 Support for disk/libdisk.o in SPL binary
3053 CONFIG_SPL_I2C_SUPPORT
3054 Support for drivers/i2c/libi2c.o in SPL binary
3056 CONFIG_SPL_GPIO_SUPPORT
3057 Support for drivers/gpio/libgpio.o in SPL binary
3059 CONFIG_SPL_MMC_SUPPORT
3060 Support for drivers/mmc/libmmc.o in SPL binary
3062 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3063 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3064 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
3065 Address, size and partition on the MMC to load U-Boot from
3066 when the MMC is being used in raw mode.
3068 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3069 Sector to load kernel uImage from when MMC is being
3070 used in raw mode (for Falcon mode)
3072 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3073 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3074 Sector and number of sectors to load kernel argument
3075 parameters from when MMC is being used in raw mode
3078 CONFIG_SPL_FAT_SUPPORT
3079 Support for fs/fat/libfat.o in SPL binary
3081 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
3082 Filename to read to load U-Boot when reading from FAT
3084 CONFIG_SPL_FAT_LOAD_KERNEL_NAME
3085 Filename to read to load kernel uImage when reading
3086 from FAT (for Falcon mode)
3088 CONFIG_SPL_FAT_LOAD_ARGS_NAME
3089 Filename to read to load kernel argument parameters
3090 when reading from FAT (for Falcon mode)
3092 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3093 Set this for NAND SPL on PPC mpc83xx targets, so that
3094 start.S waits for the rest of the SPL to load before
3095 continuing (the hardware starts execution after just
3096 loading the first page rather than the full 4K).
3098 CONFIG_SPL_NAND_BASE
3099 Include nand_base.c in the SPL. Requires
3100 CONFIG_SPL_NAND_DRIVERS.
3102 CONFIG_SPL_NAND_DRIVERS
3103 SPL uses normal NAND drivers, not minimal drivers.
3106 Include standard software ECC in the SPL
3108 CONFIG_SPL_NAND_SIMPLE
3109 Support for NAND boot using simple NAND drivers that
3110 expose the cmd_ctrl() interface.
3112 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3113 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3114 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3115 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3116 CONFIG_SYS_NAND_ECCBYTES
3117 Defines the size and behavior of the NAND that SPL uses
3120 CONFIG_SYS_NAND_U_BOOT_OFFS
3121 Location in NAND to read U-Boot from
3123 CONFIG_SYS_NAND_U_BOOT_DST
3124 Location in memory to load U-Boot to
3126 CONFIG_SYS_NAND_U_BOOT_SIZE
3127 Size of image to load
3129 CONFIG_SYS_NAND_U_BOOT_START
3130 Entry point in loaded image to jump to
3132 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3133 Define this if you need to first read the OOB and then the
3134 data. This is used for example on davinci plattforms.
3136 CONFIG_SPL_OMAP3_ID_NAND
3137 Support for an OMAP3-specific set of functions to return the
3138 ID and MFR of the first attached NAND chip, if present.
3140 CONFIG_SPL_SERIAL_SUPPORT
3141 Support for drivers/serial/libserial.o in SPL binary
3143 CONFIG_SPL_SPI_FLASH_SUPPORT
3144 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
3146 CONFIG_SPL_SPI_SUPPORT
3147 Support for drivers/spi/libspi.o in SPL binary
3149 CONFIG_SPL_RAM_DEVICE
3150 Support for running image already present in ram, in SPL binary
3152 CONFIG_SPL_LIBGENERIC_SUPPORT
3153 Support for lib/libgeneric.o in SPL binary
3155 CONFIG_SPL_ENV_SUPPORT
3156 Support for the environment operating in SPL binary
3158 CONFIG_SPL_NET_SUPPORT
3159 Support for the net/libnet.o in SPL binary.
3160 It conflicts with SPL env from storage medium specified by
3161 CONFIG_ENV_IS_xxx but CONFIG_ENV_IS_NOWHERE
3164 Image offset to which the SPL should be padded before appending
3165 the SPL payload. By default, this is defined as
3166 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3167 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3168 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3171 Final target image containing SPL and payload. Some SPLs
3172 use an arch-specific makefile fragment instead, for
3173 example if more than one image needs to be produced.
3175 CONFIG_FIT_SPL_PRINT
3176 Printing information about a FIT image adds quite a bit of
3177 code to SPL. So this is normally disabled in SPL. Use this
3178 option to re-enable it. This will affect the output of the
3179 bootm command when booting a FIT image.
3184 [so far only for SMDK2400 boards]
3186 - Modem support enable:
3187 CONFIG_MODEM_SUPPORT
3189 - RTS/CTS Flow control enable:
3192 - Modem debug support:
3193 CONFIG_MODEM_SUPPORT_DEBUG
3195 Enables debugging stuff (char screen[1024], dbg())
3196 for modem support. Useful only with BDI2000.
3198 - Interrupt support (PPC):
3200 There are common interrupt_init() and timer_interrupt()
3201 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3202 for CPU specific initialization. interrupt_init_cpu()
3203 should set decrementer_count to appropriate value. If
3204 CPU resets decrementer automatically after interrupt
3205 (ppc4xx) it should set decrementer_count to zero.
3206 timer_interrupt() calls timer_interrupt_cpu() for CPU
3207 specific handling. If board has watchdog / status_led
3208 / other_activity_monitor it works automatically from
3209 general timer_interrupt().
3213 In the target system modem support is enabled when a
3214 specific key (key combination) is pressed during
3215 power-on. Otherwise U-Boot will boot normally
3216 (autoboot). The key_pressed() function is called from
3217 board_init(). Currently key_pressed() is a dummy
3218 function, returning 1 and thus enabling modem
3221 If there are no modem init strings in the
3222 environment, U-Boot proceed to autoboot; the
3223 previous output (banner, info printfs) will be
3226 See also: doc/README.Modem
3228 Board initialization settings:
3229 ------------------------------
3231 During Initialization u-boot calls a number of board specific functions
3232 to allow the preparation of board specific prerequisites, e.g. pin setup
3233 before drivers are initialized. To enable these callbacks the
3234 following configuration macros have to be defined. Currently this is
3235 architecture specific, so please check arch/your_architecture/lib/board.c
3236 typically in board_init_f() and board_init_r().
3238 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3239 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3240 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3241 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3243 Configuration Settings:
3244 -----------------------
3246 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3247 undefine this when you're short of memory.
3249 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3250 width of the commands listed in the 'help' command output.
3252 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3253 prompt for user input.
3255 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3257 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3259 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3261 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3262 the application (usually a Linux kernel) when it is
3265 - CONFIG_SYS_BAUDRATE_TABLE:
3266 List of legal baudrate settings for this board.
3268 - CONFIG_SYS_CONSOLE_INFO_QUIET
3269 Suppress display of console information at boot.
3271 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3272 If the board specific function
3273 extern int overwrite_console (void);
3274 returns 1, the stdin, stderr and stdout are switched to the
3275 serial port, else the settings in the environment are used.
3277 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3278 Enable the call to overwrite_console().
3280 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3281 Enable overwrite of previous console environment settings.
3283 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3284 Begin and End addresses of the area used by the
3287 - CONFIG_SYS_ALT_MEMTEST:
3288 Enable an alternate, more extensive memory test.
3290 - CONFIG_SYS_MEMTEST_SCRATCH:
3291 Scratch address used by the alternate memory test
3292 You only need to set this if address zero isn't writeable
3294 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3295 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3296 this specified memory area will get subtracted from the top
3297 (end) of RAM and won't get "touched" at all by U-Boot. By
3298 fixing up gd->ram_size the Linux kernel should gets passed
3299 the now "corrected" memory size and won't touch it either.
3300 This should work for arch/ppc and arch/powerpc. Only Linux
3301 board ports in arch/powerpc with bootwrapper support that
3302 recalculate the memory size from the SDRAM controller setup
3303 will have to get fixed in Linux additionally.
3305 This option can be used as a workaround for the 440EPx/GRx
3306 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3309 WARNING: Please make sure that this value is a multiple of
3310 the Linux page size (normally 4k). If this is not the case,
3311 then the end address of the Linux memory will be located at a
3312 non page size aligned address and this could cause major
3315 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3316 Enable temporary baudrate change while serial download
3318 - CONFIG_SYS_SDRAM_BASE:
3319 Physical start address of SDRAM. _Must_ be 0 here.
3321 - CONFIG_SYS_MBIO_BASE:
3322 Physical start address of Motherboard I/O (if using a
3325 - CONFIG_SYS_FLASH_BASE:
3326 Physical start address of Flash memory.
3328 - CONFIG_SYS_MONITOR_BASE:
3329 Physical start address of boot monitor code (set by
3330 make config files to be same as the text base address
3331 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3332 CONFIG_SYS_FLASH_BASE when booting from flash.
3334 - CONFIG_SYS_MONITOR_LEN:
3335 Size of memory reserved for monitor code, used to
3336 determine _at_compile_time_ (!) if the environment is
3337 embedded within the U-Boot image, or in a separate
3340 - CONFIG_SYS_MALLOC_LEN:
3341 Size of DRAM reserved for malloc() use.
3343 - CONFIG_SYS_BOOTM_LEN:
3344 Normally compressed uImages are limited to an
3345 uncompressed size of 8 MBytes. If this is not enough,
3346 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3347 to adjust this setting to your needs.
3349 - CONFIG_SYS_BOOTMAPSZ:
3350 Maximum size of memory mapped by the startup code of
3351 the Linux kernel; all data that must be processed by
3352 the Linux kernel (bd_info, boot arguments, FDT blob if
3353 used) must be put below this limit, unless "bootm_low"
3354 enviroment variable is defined and non-zero. In such case
3355 all data for the Linux kernel must be between "bootm_low"
3356 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3357 variable "bootm_mapsize" will override the value of
3358 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3359 then the value in "bootm_size" will be used instead.
3361 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3362 Enable initrd_high functionality. If defined then the
3363 initrd_high feature is enabled and the bootm ramdisk subcommand
3366 - CONFIG_SYS_BOOT_GET_CMDLINE:
3367 Enables allocating and saving kernel cmdline in space between
3368 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3370 - CONFIG_SYS_BOOT_GET_KBD:
3371 Enables allocating and saving a kernel copy of the bd_info in
3372 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3374 - CONFIG_SYS_MAX_FLASH_BANKS:
3375 Max number of Flash memory banks
3377 - CONFIG_SYS_MAX_FLASH_SECT:
3378 Max number of sectors on a Flash chip
3380 - CONFIG_SYS_FLASH_ERASE_TOUT:
3381 Timeout for Flash erase operations (in ms)
3383 - CONFIG_SYS_FLASH_WRITE_TOUT:
3384 Timeout for Flash write operations (in ms)
3386 - CONFIG_SYS_FLASH_LOCK_TOUT
3387 Timeout for Flash set sector lock bit operation (in ms)
3389 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3390 Timeout for Flash clear lock bits operation (in ms)
3392 - CONFIG_SYS_FLASH_PROTECTION
3393 If defined, hardware flash sectors protection is used
3394 instead of U-Boot software protection.
3396 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3398 Enable TFTP transfers directly to flash memory;
3399 without this option such a download has to be
3400 performed in two steps: (1) download to RAM, and (2)
3401 copy from RAM to flash.
3403 The two-step approach is usually more reliable, since
3404 you can check if the download worked before you erase
3405 the flash, but in some situations (when system RAM is
3406 too limited to allow for a temporary copy of the
3407 downloaded image) this option may be very useful.
3409 - CONFIG_SYS_FLASH_CFI:
3410 Define if the flash driver uses extra elements in the
3411 common flash structure for storing flash geometry.
3413 - CONFIG_FLASH_CFI_DRIVER
3414 This option also enables the building of the cfi_flash driver
3415 in the drivers directory
3417 - CONFIG_FLASH_CFI_MTD
3418 This option enables the building of the cfi_mtd driver
3419 in the drivers directory. The driver exports CFI flash
3422 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3423 Use buffered writes to flash.
3425 - CONFIG_FLASH_SPANSION_S29WS_N
3426 s29ws-n MirrorBit flash has non-standard addresses for buffered
3429 - CONFIG_SYS_FLASH_QUIET_TEST
3430 If this option is defined, the common CFI flash doesn't
3431 print it's warning upon not recognized FLASH banks. This
3432 is useful, if some of the configured banks are only
3433 optionally available.
3435 - CONFIG_FLASH_SHOW_PROGRESS
3436 If defined (must be an integer), print out countdown
3437 digits and dots. Recommended value: 45 (9..1) for 80
3438 column displays, 15 (3..1) for 40 column displays.
3440 - CONFIG_FLASH_VERIFY
3441 If defined, the content of the flash (destination) is compared
3442 against the source after the write operation. An error message
3443 will be printed when the contents are not identical.
3444 Please note that this option is useless in nearly all cases,
3445 since such flash programming errors usually are detected earlier
3446 while unprotecting/erasing/programming. Please only enable
3447 this option if you really know what you are doing.
3449 - CONFIG_SYS_RX_ETH_BUFFER:
3450 Defines the number of Ethernet receive buffers. On some
3451 Ethernet controllers it is recommended to set this value
3452 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3453 buffers can be full shortly after enabling the interface
3454 on high Ethernet traffic.
3455 Defaults to 4 if not defined.
3457 - CONFIG_ENV_MAX_ENTRIES
3459 Maximum number of entries in the hash table that is used
3460 internally to store the environment settings. The default
3461 setting is supposed to be generous and should work in most
3462 cases. This setting can be used to tune behaviour; see
3463 lib/hashtable.c for details.
3465 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3466 - CONFIG_ENV_FLAGS_LIST_STATIC
3467 Enable validation of the values given to enviroment variables when
3468 calling env set. Variables can be restricted to only decimal,
3469 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3470 the variables can also be restricted to IP address or MAC address.
3472 The format of the list is:
3473 type_attribute = [s|d|x|b|i|m]
3474 access_atribute = [a|r|o|c]
3475 attributes = type_attribute[access_atribute]
3476 entry = variable_name[:attributes]
3479 The type attributes are:
3480 s - String (default)
3483 b - Boolean ([1yYtT|0nNfF])
3487 The access attributes are:
3493 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3494 Define this to a list (string) to define the ".flags"
3495 envirnoment variable in the default or embedded environment.
3497 - CONFIG_ENV_FLAGS_LIST_STATIC
3498 Define this to a list (string) to define validation that
3499 should be done if an entry is not found in the ".flags"
3500 environment variable. To override a setting in the static
3501 list, simply add an entry for the same variable name to the
3504 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3505 If defined, don't allow the -f switch to env set override variable
3508 - CONFIG_SYS_GENERIC_BOARD
3509 This selects the architecture-generic board system instead of the
3510 architecture-specific board files. It is intended to move boards
3511 to this new framework over time. Defining this will disable the
3512 arch/foo/lib/board.c file and use common/board_f.c and
3513 common/board_r.c instead. To use this option your architecture
3514 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3515 its config.mk file). If you find problems enabling this option on
3516 your board please report the problem and send patches!
3518 - CONFIG_SYS_SYM_OFFSETS
3519 This is set by architectures that use offsets for link symbols
3520 instead of absolute values. So bss_start is obtained using an
3521 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3522 directly. You should not need to touch this setting.
3524 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3525 This is set by OMAP boards for the max time that reset should
3526 be asserted. See doc/README.omap-reset-time for details on how
3527 the value can be calulated on a given board.
3529 The following definitions that deal with the placement and management
3530 of environment data (variable area); in general, we support the
3531 following configurations:
3533 - CONFIG_BUILD_ENVCRC:
3535 Builds up envcrc with the target environment so that external utils
3536 may easily extract it and embed it in final U-Boot images.
3538 - CONFIG_ENV_IS_IN_FLASH:
3540 Define this if the environment is in flash memory.
3542 a) The environment occupies one whole flash sector, which is
3543 "embedded" in the text segment with the U-Boot code. This
3544 happens usually with "bottom boot sector" or "top boot
3545 sector" type flash chips, which have several smaller
3546 sectors at the start or the end. For instance, such a
3547 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3548 such a case you would place the environment in one of the
3549 4 kB sectors - with U-Boot code before and after it. With
3550 "top boot sector" type flash chips, you would put the
3551 environment in one of the last sectors, leaving a gap
3552 between U-Boot and the environment.
3554 - CONFIG_ENV_OFFSET:
3556 Offset of environment data (variable area) to the
3557 beginning of flash memory; for instance, with bottom boot
3558 type flash chips the second sector can be used: the offset
3559 for this sector is given here.
3561 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3565 This is just another way to specify the start address of
3566 the flash sector containing the environment (instead of
3569 - CONFIG_ENV_SECT_SIZE:
3571 Size of the sector containing the environment.
3574 b) Sometimes flash chips have few, equal sized, BIG sectors.
3575 In such a case you don't want to spend a whole sector for
3580 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3581 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3582 of this flash sector for the environment. This saves
3583 memory for the RAM copy of the environment.
3585 It may also save flash memory if you decide to use this
3586 when your environment is "embedded" within U-Boot code,
3587 since then the remainder of the flash sector could be used
3588 for U-Boot code. It should be pointed out that this is
3589 STRONGLY DISCOURAGED from a robustness point of view:
3590 updating the environment in flash makes it always
3591 necessary to erase the WHOLE sector. If something goes
3592 wrong before the contents has been restored from a copy in
3593 RAM, your target system will be dead.
3595 - CONFIG_ENV_ADDR_REDUND
3596 CONFIG_ENV_SIZE_REDUND
3598 These settings describe a second storage area used to hold
3599 a redundant copy of the environment data, so that there is
3600 a valid backup copy in case there is a power failure during
3601 a "saveenv" operation.
3603 BE CAREFUL! Any changes to the flash layout, and some changes to the
3604 source code will make it necessary to adapt <board>/u-boot.lds*
3608 - CONFIG_ENV_IS_IN_NVRAM:
3610 Define this if you have some non-volatile memory device
3611 (NVRAM, battery buffered SRAM) which you want to use for the
3617 These two #defines are used to determine the memory area you
3618 want to use for environment. It is assumed that this memory
3619 can just be read and written to, without any special
3622 BE CAREFUL! The first access to the environment happens quite early
3623 in U-Boot initalization (when we try to get the setting of for the
3624 console baudrate). You *MUST* have mapped your NVRAM area then, or
3627 Please note that even with NVRAM we still use a copy of the
3628 environment in RAM: we could work on NVRAM directly, but we want to
3629 keep settings there always unmodified except somebody uses "saveenv"
3630 to save the current settings.
3633 - CONFIG_ENV_IS_IN_EEPROM:
3635 Use this if you have an EEPROM or similar serial access
3636 device and a driver for it.
3638 - CONFIG_ENV_OFFSET:
3641 These two #defines specify the offset and size of the
3642 environment area within the total memory of your EEPROM.
3644 - CONFIG_SYS_I2C_EEPROM_ADDR:
3645 If defined, specified the chip address of the EEPROM device.
3646 The default address is zero.
3648 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3649 If defined, the number of bits used to address bytes in a
3650 single page in the EEPROM device. A 64 byte page, for example
3651 would require six bits.
3653 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3654 If defined, the number of milliseconds to delay between
3655 page writes. The default is zero milliseconds.
3657 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3658 The length in bytes of the EEPROM memory array address. Note
3659 that this is NOT the chip address length!
3661 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3662 EEPROM chips that implement "address overflow" are ones
3663 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3664 address and the extra bits end up in the "chip address" bit
3665 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3668 Note that we consider the length of the address field to
3669 still be one byte because the extra address bits are hidden
3670 in the chip address.
3672 - CONFIG_SYS_EEPROM_SIZE:
3673 The size in bytes of the EEPROM device.
3675 - CONFIG_ENV_EEPROM_IS_ON_I2C
3676 define this, if you have I2C and SPI activated, and your
3677 EEPROM, which holds the environment, is on the I2C bus.
3679 - CONFIG_I2C_ENV_EEPROM_BUS
3680 if you have an Environment on an EEPROM reached over
3681 I2C muxes, you can define here, how to reach this
3682 EEPROM. For example:
3684 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3686 EEPROM which holds the environment, is reached over
3687 a pca9547 i2c mux with address 0x70, channel 3.
3689 - CONFIG_ENV_IS_IN_DATAFLASH:
3691 Define this if you have a DataFlash memory device which you
3692 want to use for the environment.
3694 - CONFIG_ENV_OFFSET:
3698 These three #defines specify the offset and size of the
3699 environment area within the total memory of your DataFlash placed
3700 at the specified address.
3702 - CONFIG_ENV_IS_IN_REMOTE:
3704 Define this if you have a remote memory space which you
3705 want to use for the local device's environment.
3710 These two #defines specify the address and size of the
3711 environment area within the remote memory space. The
3712 local device can get the environment from remote memory
3713 space by SRIO or PCIE links.
3715 BE CAREFUL! For some special cases, the local device can not use
3716 "saveenv" command. For example, the local device will get the
3717 environment stored in a remote NOR flash by SRIO or PCIE link,
3718 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3720 - CONFIG_ENV_IS_IN_NAND:
3722 Define this if you have a NAND device which you want to use
3723 for the environment.
3725 - CONFIG_ENV_OFFSET:
3728 These two #defines specify the offset and size of the environment
3729 area within the first NAND device. CONFIG_ENV_OFFSET must be
3730 aligned to an erase block boundary.
3732 - CONFIG_ENV_OFFSET_REDUND (optional):
3734 This setting describes a second storage area of CONFIG_ENV_SIZE
3735 size used to hold a redundant copy of the environment data, so
3736 that there is a valid backup copy in case there is a power failure
3737 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3738 aligned to an erase block boundary.
3740 - CONFIG_ENV_RANGE (optional):
3742 Specifies the length of the region in which the environment
3743 can be written. This should be a multiple of the NAND device's
3744 block size. Specifying a range with more erase blocks than
3745 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3746 the range to be avoided.
3748 - CONFIG_ENV_OFFSET_OOB (optional):
3750 Enables support for dynamically retrieving the offset of the
3751 environment from block zero's out-of-band data. The
3752 "nand env.oob" command can be used to record this offset.
3753 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3754 using CONFIG_ENV_OFFSET_OOB.
3756 - CONFIG_NAND_ENV_DST
3758 Defines address in RAM to which the nand_spl code should copy the
3759 environment. If redundant environment is used, it will be copied to
3760 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3762 - CONFIG_ENV_IS_IN_UBI:
3764 Define this if you have an UBI volume that you want to use for the
3765 environment. This has the benefit of wear-leveling the environment
3766 accesses, which is important on NAND.
3768 - CONFIG_ENV_UBI_PART:
3770 Define this to a string that is the mtd partition containing the UBI.
3772 - CONFIG_ENV_UBI_VOLUME:
3774 Define this to the name of the volume that you want to store the
3777 - CONFIG_ENV_UBI_VOLUME_REDUND:
3779 Define this to the name of another volume to store a second copy of
3780 the environment in. This will enable redundant environments in UBI.
3781 It is assumed that both volumes are in the same MTD partition.
3783 - CONFIG_UBI_SILENCE_MSG
3784 - CONFIG_UBIFS_SILENCE_MSG
3786 You will probably want to define these to avoid a really noisy system
3787 when storing the env in UBI.
3789 - CONFIG_ENV_IS_IN_MMC:
3791 Define this if you have an MMC device which you want to use for the
3794 - CONFIG_SYS_MMC_ENV_DEV:
3796 Specifies which MMC device the environment is stored in.
3798 - CONFIG_SYS_MMC_ENV_PART (optional):
3800 Specifies which MMC partition the environment is stored in. If not
3801 set, defaults to partition 0, the user area. Common values might be
3802 1 (first MMC boot partition), 2 (second MMC boot partition).
3804 - CONFIG_ENV_OFFSET:
3807 These two #defines specify the offset and size of the environment
3808 area within the specified MMC device.
3810 If offset is positive (the usual case), it is treated as relative to
3811 the start of the MMC partition. If offset is negative, it is treated
3812 as relative to the end of the MMC partition. This can be useful if
3813 your board may be fitted with different MMC devices, which have
3814 different sizes for the MMC partitions, and you always want the
3815 environment placed at the very end of the partition, to leave the
3816 maximum possible space before it, to store other data.
3818 These two values are in units of bytes, but must be aligned to an
3819 MMC sector boundary.
3821 - CONFIG_ENV_OFFSET_REDUND (optional):
3823 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3824 hold a redundant copy of the environment data. This provides a
3825 valid backup copy in case the other copy is corrupted, e.g. due
3826 to a power failure during a "saveenv" operation.
3828 This value may also be positive or negative; this is handled in the
3829 same way as CONFIG_ENV_OFFSET.
3831 This value is also in units of bytes, but must also be aligned to
3832 an MMC sector boundary.
3834 - CONFIG_ENV_SIZE_REDUND (optional):
3836 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3837 set. If this value is set, it must be set to the same value as
3840 - CONFIG_SYS_SPI_INIT_OFFSET
3842 Defines offset to the initial SPI buffer area in DPRAM. The
3843 area is used at an early stage (ROM part) if the environment
3844 is configured to reside in the SPI EEPROM: We need a 520 byte
3845 scratch DPRAM area. It is used between the two initialization
3846 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3847 to be a good choice since it makes it far enough from the
3848 start of the data area as well as from the stack pointer.
3850 Please note that the environment is read-only until the monitor
3851 has been relocated to RAM and a RAM copy of the environment has been
3852 created; also, when using EEPROM you will have to use getenv_f()
3853 until then to read environment variables.
3855 The environment is protected by a CRC32 checksum. Before the monitor
3856 is relocated into RAM, as a result of a bad CRC you will be working
3857 with the compiled-in default environment - *silently*!!! [This is
3858 necessary, because the first environment variable we need is the
3859 "baudrate" setting for the console - if we have a bad CRC, we don't
3860 have any device yet where we could complain.]
3862 Note: once the monitor has been relocated, then it will complain if
3863 the default environment is used; a new CRC is computed as soon as you
3864 use the "saveenv" command to store a valid environment.
3866 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3867 Echo the inverted Ethernet link state to the fault LED.
3869 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3870 also needs to be defined.
3872 - CONFIG_SYS_FAULT_MII_ADDR:
3873 MII address of the PHY to check for the Ethernet link state.
3875 - CONFIG_NS16550_MIN_FUNCTIONS:
3876 Define this if you desire to only have use of the NS16550_init
3877 and NS16550_putc functions for the serial driver located at
3878 drivers/serial/ns16550.c. This option is useful for saving
3879 space for already greatly restricted images, including but not
3880 limited to NAND_SPL configurations.
3882 - CONFIG_DISPLAY_BOARDINFO
3883 Display information about the board that U-Boot is running on
3884 when U-Boot starts up. The board function checkboard() is called
3887 - CONFIG_DISPLAY_BOARDINFO_LATE
3888 Similar to the previous option, but display this information
3889 later, once stdio is running and output goes to the LCD, if
3892 Low Level (hardware related) configuration options:
3893 ---------------------------------------------------
3895 - CONFIG_SYS_CACHELINE_SIZE:
3896 Cache Line Size of the CPU.
3898 - CONFIG_SYS_DEFAULT_IMMR:
3899 Default address of the IMMR after system reset.
3901 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3902 and RPXsuper) to be able to adjust the position of
3903 the IMMR register after a reset.
3905 - CONFIG_SYS_CCSRBAR_DEFAULT:
3906 Default (power-on reset) physical address of CCSR on Freescale
3909 - CONFIG_SYS_CCSRBAR:
3910 Virtual address of CCSR. On a 32-bit build, this is typically
3911 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3913 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3914 for cross-platform code that uses that macro instead.
3916 - CONFIG_SYS_CCSRBAR_PHYS:
3917 Physical address of CCSR. CCSR can be relocated to a new
3918 physical address, if desired. In this case, this macro should
3919 be set to that address. Otherwise, it should be set to the
3920 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3921 is typically relocated on 36-bit builds. It is recommended
3922 that this macro be defined via the _HIGH and _LOW macros:
3924 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3925 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3927 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3928 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3929 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3930 used in assembly code, so it must not contain typecasts or
3931 integer size suffixes (e.g. "ULL").
3933 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3934 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3935 used in assembly code, so it must not contain typecasts or
3936 integer size suffixes (e.g. "ULL").
3938 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3939 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3940 forced to a value that ensures that CCSR is not relocated.
3942 - Floppy Disk Support:
3943 CONFIG_SYS_FDC_DRIVE_NUMBER
3945 the default drive number (default value 0)
3947 CONFIG_SYS_ISA_IO_STRIDE
3949 defines the spacing between FDC chipset registers
3952 CONFIG_SYS_ISA_IO_OFFSET
3954 defines the offset of register from address. It
3955 depends on which part of the data bus is connected to
3956 the FDC chipset. (default value 0)
3958 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3959 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3962 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3963 fdc_hw_init() is called at the beginning of the FDC
3964 setup. fdc_hw_init() must be provided by the board
3965 source code. It is used to make hardware dependant
3969 Most IDE controllers were designed to be connected with PCI
3970 interface. Only few of them were designed for AHB interface.
3971 When software is doing ATA command and data transfer to
3972 IDE devices through IDE-AHB controller, some additional
3973 registers accessing to these kind of IDE-AHB controller
3976 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3977 DO NOT CHANGE unless you know exactly what you're
3978 doing! (11-4) [MPC8xx/82xx systems only]
3980 - CONFIG_SYS_INIT_RAM_ADDR:
3982 Start address of memory area that can be used for
3983 initial data and stack; please note that this must be
3984 writable memory that is working WITHOUT special
3985 initialization, i. e. you CANNOT use normal RAM which
3986 will become available only after programming the
3987 memory controller and running certain initialization
3990 U-Boot uses the following memory types:
3991 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3992 - MPC824X: data cache
3993 - PPC4xx: data cache
3995 - CONFIG_SYS_GBL_DATA_OFFSET:
3997 Offset of the initial data structure in the memory
3998 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3999 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4000 data is located at the end of the available space
4001 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4002 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4003 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4004 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4007 On the MPC824X (or other systems that use the data
4008 cache for initial memory) the address chosen for
4009 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4010 point to an otherwise UNUSED address space between
4011 the top of RAM and the start of the PCI space.
4013 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4015 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4017 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4019 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4021 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4023 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4025 - CONFIG_SYS_OR_TIMING_SDRAM:
4028 - CONFIG_SYS_MAMR_PTA:
4029 periodic timer for refresh
4031 - CONFIG_SYS_DER: Debug Event Register (37-47)
4033 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4034 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4035 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4036 CONFIG_SYS_BR1_PRELIM:
4037 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4039 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4040 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4041 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4042 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4044 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4045 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4046 Machine Mode Register and Memory Periodic Timer
4047 Prescaler definitions (SDRAM timing)
4049 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4050 enable I2C microcode relocation patch (MPC8xx);
4051 define relocation offset in DPRAM [DSP2]
4053 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4054 enable SMC microcode relocation patch (MPC8xx);
4055 define relocation offset in DPRAM [SMC1]
4057 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4058 enable SPI microcode relocation patch (MPC8xx);
4059 define relocation offset in DPRAM [SCC4]
4061 - CONFIG_SYS_USE_OSCCLK:
4062 Use OSCM clock mode on MBX8xx board. Be careful,
4063 wrong setting might damage your board. Read
4064 doc/README.MBX before setting this variable!
4066 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4067 Offset of the bootmode word in DPRAM used by post
4068 (Power On Self Tests). This definition overrides
4069 #define'd default value in commproc.h resp.
4072 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4073 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4074 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4075 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4076 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4077 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4078 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4079 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4080 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4082 - CONFIG_PCI_DISABLE_PCIE:
4083 Disable PCI-Express on systems where it is supported but not
4086 - CONFIG_PCI_ENUM_ONLY
4087 Only scan through and get the devices on the busses.
4088 Don't do any setup work, presumably because someone or
4089 something has already done it, and we don't need to do it
4090 a second time. Useful for platforms that are pre-booted
4091 by coreboot or similar.
4093 - CONFIG_PCI_INDIRECT_BRIDGE:
4094 Enable support for indirect PCI bridges.
4097 Chip has SRIO or not
4100 Board has SRIO 1 port available
4103 Board has SRIO 2 port available
4105 - CONFIG_SRIO_PCIE_BOOT_MASTER
4106 Board can support master function for Boot from SRIO and PCIE
4108 - CONFIG_SYS_SRIOn_MEM_VIRT:
4109 Virtual Address of SRIO port 'n' memory region
4111 - CONFIG_SYS_SRIOn_MEM_PHYS:
4112 Physical Address of SRIO port 'n' memory region
4114 - CONFIG_SYS_SRIOn_MEM_SIZE:
4115 Size of SRIO port 'n' memory region
4117 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4118 Defined to tell the NAND controller that the NAND chip is using
4120 Not all NAND drivers use this symbol.
4121 Example of drivers that use it:
4122 - drivers/mtd/nand/ndfc.c
4123 - drivers/mtd/nand/mxc_nand.c
4125 - CONFIG_SYS_NDFC_EBC0_CFG
4126 Sets the EBC0_CFG register for the NDFC. If not defined
4127 a default value will be used.
4130 Get DDR timing information from an I2C EEPROM. Common
4131 with pluggable memory modules such as SODIMMs
4134 I2C address of the SPD EEPROM
4136 - CONFIG_SYS_SPD_BUS_NUM
4137 If SPD EEPROM is on an I2C bus other than the first
4138 one, specify here. Note that the value must resolve
4139 to something your driver can deal with.
4141 - CONFIG_SYS_DDR_RAW_TIMING
4142 Get DDR timing information from other than SPD. Common with
4143 soldered DDR chips onboard without SPD. DDR raw timing
4144 parameters are extracted from datasheet and hard-coded into
4145 header files or board specific files.
4147 - CONFIG_FSL_DDR_INTERACTIVE
4148 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4150 - CONFIG_SYS_83XX_DDR_USES_CS0
4151 Only for 83xx systems. If specified, then DDR should
4152 be configured using CS0 and CS1 instead of CS2 and CS3.
4154 - CONFIG_ETHER_ON_FEC[12]
4155 Define to enable FEC[12] on a 8xx series processor.
4157 - CONFIG_FEC[12]_PHY
4158 Define to the hardcoded PHY address which corresponds
4159 to the given FEC; i. e.
4160 #define CONFIG_FEC1_PHY 4
4161 means that the PHY with address 4 is connected to FEC1
4163 When set to -1, means to probe for first available.
4165 - CONFIG_FEC[12]_PHY_NORXERR
4166 The PHY does not have a RXERR line (RMII only).
4167 (so program the FEC to ignore it).
4170 Enable RMII mode for all FECs.
4171 Note that this is a global option, we can't
4172 have one FEC in standard MII mode and another in RMII mode.
4174 - CONFIG_CRC32_VERIFY
4175 Add a verify option to the crc32 command.
4178 => crc32 -v <address> <count> <crc32>
4180 Where address/count indicate a memory area
4181 and crc32 is the correct crc32 which the
4185 Add the "loopw" memory command. This only takes effect if
4186 the memory commands are activated globally (CONFIG_CMD_MEM).
4189 Add the "mdc" and "mwc" memory commands. These are cyclic
4194 This command will print 4 bytes (10,11,12,13) each 500 ms.
4196 => mwc.l 100 12345678 10
4197 This command will write 12345678 to address 100 all 10 ms.
4199 This only takes effect if the memory commands are activated
4200 globally (CONFIG_CMD_MEM).
4202 - CONFIG_SKIP_LOWLEVEL_INIT
4203 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4204 low level initializations (like setting up the memory
4205 controller) are omitted and/or U-Boot does not
4206 relocate itself into RAM.
4208 Normally this variable MUST NOT be defined. The only
4209 exception is when U-Boot is loaded (to RAM) by some
4210 other boot loader or by a debugger which performs
4211 these initializations itself.
4214 Modifies the behaviour of start.S when compiling a loader
4215 that is executed before the actual U-Boot. E.g. when
4216 compiling a NAND SPL.
4218 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4219 Only for 85xx systems. If this variable is specified, the section
4220 .resetvec is not kept and the section .bootpg is placed in the
4221 previous 4k of the .text section.
4223 - CONFIG_ARCH_MAP_SYSMEM
4224 Generally U-Boot (and in particular the md command) uses
4225 effective address. It is therefore not necessary to regard
4226 U-Boot address as virtual addresses that need to be translated
4227 to physical addresses. However, sandbox requires this, since
4228 it maintains its own little RAM buffer which contains all
4229 addressable memory. This option causes some memory accesses
4230 to be mapped through map_sysmem() / unmap_sysmem().
4232 - CONFIG_USE_ARCH_MEMCPY
4233 CONFIG_USE_ARCH_MEMSET
4234 If these options are used a optimized version of memcpy/memset will
4235 be used if available. These functions may be faster under some
4236 conditions but may increase the binary size.
4238 - CONFIG_X86_RESET_VECTOR
4239 If defined, the x86 reset vector code is included. This is not
4240 needed when U-Boot is running from Coreboot.
4243 Defines the MPU clock speed (in MHz).
4245 NOTE : currently only supported on AM335x platforms.
4247 Freescale QE/FMAN Firmware Support:
4248 -----------------------------------
4250 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4251 loading of "firmware", which is encoded in the QE firmware binary format.
4252 This firmware often needs to be loaded during U-Boot booting, so macros
4253 are used to identify the storage device (NOR flash, SPI, etc) and the address
4256 - CONFIG_SYS_QE_FMAN_FW_ADDR
4257 The address in the storage device where the firmware is located. The
4258 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4261 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4262 The maximum possible size of the firmware. The firmware binary format
4263 has a field that specifies the actual size of the firmware, but it
4264 might not be possible to read any part of the firmware unless some
4265 local storage is allocated to hold the entire firmware first.
4267 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4268 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4269 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4270 virtual address in NOR flash.
4272 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4273 Specifies that QE/FMAN firmware is located in NAND flash.
4274 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4276 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4277 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4278 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4280 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4281 Specifies that QE/FMAN firmware is located on the primary SPI
4282 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4284 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4285 Specifies that QE/FMAN firmware is located in the remote (master)
4286 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4287 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4288 window->master inbound window->master LAW->the ucode address in
4289 master's memory space.
4291 Building the Software:
4292 ======================
4294 Building U-Boot has been tested in several native build environments
4295 and in many different cross environments. Of course we cannot support
4296 all possibly existing versions of cross development tools in all
4297 (potentially obsolete) versions. In case of tool chain problems we
4298 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4299 which is extensively used to build and test U-Boot.
4301 If you are not using a native environment, it is assumed that you
4302 have GNU cross compiling tools available in your path. In this case,
4303 you must set the environment variable CROSS_COMPILE in your shell.
4304 Note that no changes to the Makefile or any other source files are
4305 necessary. For example using the ELDK on a 4xx CPU, please enter:
4307 $ CROSS_COMPILE=ppc_4xx-
4308 $ export CROSS_COMPILE
4310 Note: If you wish to generate Windows versions of the utilities in
4311 the tools directory you can use the MinGW toolchain
4312 (http://www.mingw.org). Set your HOST tools to the MinGW
4313 toolchain and execute 'make tools'. For example:
4315 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4317 Binaries such as tools/mkimage.exe will be created which can
4318 be executed on computers running Windows.
4320 U-Boot is intended to be simple to build. After installing the
4321 sources you must configure U-Boot for one specific board type. This
4326 where "NAME_config" is the name of one of the existing configu-
4327 rations; see boards.cfg for supported names.
4329 Note: for some board special configuration names may exist; check if
4330 additional information is available from the board vendor; for
4331 instance, the TQM823L systems are available without (standard)
4332 or with LCD support. You can select such additional "features"
4333 when choosing the configuration, i. e.
4336 - will configure for a plain TQM823L, i. e. no LCD support
4338 make TQM823L_LCD_config
4339 - will configure for a TQM823L with U-Boot console on LCD
4344 Finally, type "make all", and you should get some working U-Boot
4345 images ready for download to / installation on your system:
4347 - "u-boot.bin" is a raw binary image
4348 - "u-boot" is an image in ELF binary format
4349 - "u-boot.srec" is in Motorola S-Record format
4351 By default the build is performed locally and the objects are saved
4352 in the source directory. One of the two methods can be used to change
4353 this behavior and build U-Boot to some external directory:
4355 1. Add O= to the make command line invocations:
4357 make O=/tmp/build distclean
4358 make O=/tmp/build NAME_config
4359 make O=/tmp/build all
4361 2. Set environment variable BUILD_DIR to point to the desired location:
4363 export BUILD_DIR=/tmp/build
4368 Note that the command line "O=" setting overrides the BUILD_DIR environment
4372 Please be aware that the Makefiles assume you are using GNU make, so
4373 for instance on NetBSD you might need to use "gmake" instead of
4377 If the system board that you have is not listed, then you will need
4378 to port U-Boot to your hardware platform. To do this, follow these
4381 1. Add a new configuration option for your board to the toplevel
4382 "boards.cfg" file, using the existing entries as examples.
4383 Follow the instructions there to keep the boards in order.
4384 2. Create a new directory to hold your board specific code. Add any
4385 files you need. In your board directory, you will need at least
4386 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4387 3. Create a new configuration file "include/configs/<board>.h" for
4389 3. If you're porting U-Boot to a new CPU, then also create a new
4390 directory to hold your CPU specific code. Add any files you need.
4391 4. Run "make <board>_config" with your new name.
4392 5. Type "make", and you should get a working "u-boot.srec" file
4393 to be installed on your target system.
4394 6. Debug and solve any problems that might arise.
4395 [Of course, this last step is much harder than it sounds.]
4398 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4399 ==============================================================
4401 If you have modified U-Boot sources (for instance added a new board
4402 or support for new devices, a new CPU, etc.) you are expected to
4403 provide feedback to the other developers. The feedback normally takes
4404 the form of a "patch", i. e. a context diff against a certain (latest
4405 official or latest in the git repository) version of U-Boot sources.
4407 But before you submit such a patch, please verify that your modifi-
4408 cation did not break existing code. At least make sure that *ALL* of
4409 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4410 just run the "MAKEALL" script, which will configure and build U-Boot
4411 for ALL supported system. Be warned, this will take a while. You can
4412 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4413 environment variable to the script, i. e. to use the ELDK cross tools
4416 CROSS_COMPILE=ppc_8xx- MAKEALL
4418 or to build on a native PowerPC system you can type
4420 CROSS_COMPILE=' ' MAKEALL
4422 When using the MAKEALL script, the default behaviour is to build
4423 U-Boot in the source directory. This location can be changed by
4424 setting the BUILD_DIR environment variable. Also, for each target
4425 built, the MAKEALL script saves two log files (<target>.ERR and
4426 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4427 location can be changed by setting the MAKEALL_LOGDIR environment
4428 variable. For example:
4430 export BUILD_DIR=/tmp/build
4431 export MAKEALL_LOGDIR=/tmp/log
4432 CROSS_COMPILE=ppc_8xx- MAKEALL
4434 With the above settings build objects are saved in the /tmp/build,
4435 log files are saved in the /tmp/log and the source tree remains clean
4436 during the whole build process.
4439 See also "U-Boot Porting Guide" below.
4442 Monitor Commands - Overview:
4443 ============================
4445 go - start application at address 'addr'
4446 run - run commands in an environment variable
4447 bootm - boot application image from memory
4448 bootp - boot image via network using BootP/TFTP protocol
4449 bootz - boot zImage from memory
4450 tftpboot- boot image via network using TFTP protocol
4451 and env variables "ipaddr" and "serverip"
4452 (and eventually "gatewayip")
4453 tftpput - upload a file via network using TFTP protocol
4454 rarpboot- boot image via network using RARP/TFTP protocol
4455 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4456 loads - load S-Record file over serial line
4457 loadb - load binary file over serial line (kermit mode)
4459 mm - memory modify (auto-incrementing)
4460 nm - memory modify (constant address)
4461 mw - memory write (fill)
4463 cmp - memory compare
4464 crc32 - checksum calculation
4465 i2c - I2C sub-system
4466 sspi - SPI utility commands
4467 base - print or set address offset
4468 printenv- print environment variables
4469 setenv - set environment variables
4470 saveenv - save environment variables to persistent storage
4471 protect - enable or disable FLASH write protection
4472 erase - erase FLASH memory
4473 flinfo - print FLASH memory information
4474 nand - NAND memory operations (see doc/README.nand)
4475 bdinfo - print Board Info structure
4476 iminfo - print header information for application image
4477 coninfo - print console devices and informations
4478 ide - IDE sub-system
4479 loop - infinite loop on address range
4480 loopw - infinite write loop on address range
4481 mtest - simple RAM test
4482 icache - enable or disable instruction cache
4483 dcache - enable or disable data cache
4484 reset - Perform RESET of the CPU
4485 echo - echo args to console
4486 version - print monitor version
4487 help - print online help
4488 ? - alias for 'help'
4491 Monitor Commands - Detailed Description:
4492 ========================================
4496 For now: just type "help <command>".
4499 Environment Variables:
4500 ======================
4502 U-Boot supports user configuration using Environment Variables which
4503 can be made persistent by saving to Flash memory.
4505 Environment Variables are set using "setenv", printed using
4506 "printenv", and saved to Flash using "saveenv". Using "setenv"
4507 without a value can be used to delete a variable from the
4508 environment. As long as you don't save the environment you are
4509 working with an in-memory copy. In case the Flash area containing the
4510 environment is erased by accident, a default environment is provided.
4512 Some configuration options can be set using Environment Variables.
4514 List of environment variables (most likely not complete):
4516 baudrate - see CONFIG_BAUDRATE
4518 bootdelay - see CONFIG_BOOTDELAY
4520 bootcmd - see CONFIG_BOOTCOMMAND
4522 bootargs - Boot arguments when booting an RTOS image
4524 bootfile - Name of the image to load with TFTP
4526 bootm_low - Memory range available for image processing in the bootm
4527 command can be restricted. This variable is given as
4528 a hexadecimal number and defines lowest address allowed
4529 for use by the bootm command. See also "bootm_size"
4530 environment variable. Address defined by "bootm_low" is
4531 also the base of the initial memory mapping for the Linux
4532 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4535 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4536 This variable is given as a hexadecimal number and it
4537 defines the size of the memory region starting at base
4538 address bootm_low that is accessible by the Linux kernel
4539 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4540 as the default value if it is defined, and bootm_size is
4543 bootm_size - Memory range available for image processing in the bootm
4544 command can be restricted. This variable is given as
4545 a hexadecimal number and defines the size of the region
4546 allowed for use by the bootm command. See also "bootm_low"
4547 environment variable.
4549 updatefile - Location of the software update file on a TFTP server, used
4550 by the automatic software update feature. Please refer to
4551 documentation in doc/README.update for more details.
4553 autoload - if set to "no" (any string beginning with 'n'),
4554 "bootp" will just load perform a lookup of the
4555 configuration from the BOOTP server, but not try to
4556 load any image using TFTP
4558 autostart - if set to "yes", an image loaded using the "bootp",
4559 "rarpboot", "tftpboot" or "diskboot" commands will
4560 be automatically started (by internally calling
4563 If set to "no", a standalone image passed to the
4564 "bootm" command will be copied to the load address
4565 (and eventually uncompressed), but NOT be started.
4566 This can be used to load and uncompress arbitrary
4569 fdt_high - if set this restricts the maximum address that the
4570 flattened device tree will be copied into upon boot.
4571 For example, if you have a system with 1 GB memory
4572 at physical address 0x10000000, while Linux kernel
4573 only recognizes the first 704 MB as low memory, you
4574 may need to set fdt_high as 0x3C000000 to have the
4575 device tree blob be copied to the maximum address
4576 of the 704 MB low memory, so that Linux kernel can
4577 access it during the boot procedure.
4579 If this is set to the special value 0xFFFFFFFF then
4580 the fdt will not be copied at all on boot. For this
4581 to work it must reside in writable memory, have
4582 sufficient padding on the end of it for u-boot to
4583 add the information it needs into it, and the memory
4584 must be accessible by the kernel.
4586 fdtcontroladdr- if set this is the address of the control flattened
4587 device tree used by U-Boot when CONFIG_OF_CONTROL is
4590 i2cfast - (PPC405GP|PPC405EP only)
4591 if set to 'y' configures Linux I2C driver for fast
4592 mode (400kHZ). This environment variable is used in
4593 initialization code. So, for changes to be effective
4594 it must be saved and board must be reset.
4596 initrd_high - restrict positioning of initrd images:
4597 If this variable is not set, initrd images will be
4598 copied to the highest possible address in RAM; this
4599 is usually what you want since it allows for
4600 maximum initrd size. If for some reason you want to
4601 make sure that the initrd image is loaded below the
4602 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4603 variable to a value of "no" or "off" or "0".
4604 Alternatively, you can set it to a maximum upper
4605 address to use (U-Boot will still check that it
4606 does not overwrite the U-Boot stack and data).
4608 For instance, when you have a system with 16 MB
4609 RAM, and want to reserve 4 MB from use by Linux,
4610 you can do this by adding "mem=12M" to the value of
4611 the "bootargs" variable. However, now you must make
4612 sure that the initrd image is placed in the first
4613 12 MB as well - this can be done with
4615 setenv initrd_high 00c00000
4617 If you set initrd_high to 0xFFFFFFFF, this is an
4618 indication to U-Boot that all addresses are legal
4619 for the Linux kernel, including addresses in flash
4620 memory. In this case U-Boot will NOT COPY the
4621 ramdisk at all. This may be useful to reduce the
4622 boot time on your system, but requires that this
4623 feature is supported by your Linux kernel.
4625 ipaddr - IP address; needed for tftpboot command
4627 loadaddr - Default load address for commands like "bootp",
4628 "rarpboot", "tftpboot", "loadb" or "diskboot"
4630 loads_echo - see CONFIG_LOADS_ECHO
4632 serverip - TFTP server IP address; needed for tftpboot command
4634 bootretry - see CONFIG_BOOT_RETRY_TIME
4636 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4638 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4640 ethprime - controls which interface is used first.
4642 ethact - controls which interface is currently active.
4643 For example you can do the following
4645 => setenv ethact FEC
4646 => ping 192.168.0.1 # traffic sent on FEC
4647 => setenv ethact SCC
4648 => ping 10.0.0.1 # traffic sent on SCC
4650 ethrotate - When set to "no" U-Boot does not go through all
4651 available network interfaces.
4652 It just stays at the currently selected interface.
4654 netretry - When set to "no" each network operation will
4655 either succeed or fail without retrying.
4656 When set to "once" the network operation will
4657 fail when all the available network interfaces
4658 are tried once without success.
4659 Useful on scripts which control the retry operation
4662 npe_ucode - set load address for the NPE microcode
4664 tftpsrcport - If this is set, the value is used for TFTP's
4667 tftpdstport - If this is set, the value is used for TFTP's UDP
4668 destination port instead of the Well Know Port 69.
4670 tftpblocksize - Block size to use for TFTP transfers; if not set,
4671 we use the TFTP server's default block size
4673 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4674 seconds, minimum value is 1000 = 1 second). Defines
4675 when a packet is considered to be lost so it has to
4676 be retransmitted. The default is 5000 = 5 seconds.
4677 Lowering this value may make downloads succeed
4678 faster in networks with high packet loss rates or
4679 with unreliable TFTP servers.
4681 vlan - When set to a value < 4095 the traffic over
4682 Ethernet is encapsulated/received over 802.1q
4685 The following image location variables contain the location of images
4686 used in booting. The "Image" column gives the role of the image and is
4687 not an environment variable name. The other columns are environment
4688 variable names. "File Name" gives the name of the file on a TFTP
4689 server, "RAM Address" gives the location in RAM the image will be
4690 loaded to, and "Flash Location" gives the image's address in NOR
4691 flash or offset in NAND flash.
4693 *Note* - these variables don't have to be defined for all boards, some
4694 boards currenlty use other variables for these purposes, and some
4695 boards use these variables for other purposes.
4697 Image File Name RAM Address Flash Location
4698 ----- --------- ----------- --------------
4699 u-boot u-boot u-boot_addr_r u-boot_addr
4700 Linux kernel bootfile kernel_addr_r kernel_addr
4701 device tree blob fdtfile fdt_addr_r fdt_addr
4702 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4704 The following environment variables may be used and automatically
4705 updated by the network boot commands ("bootp" and "rarpboot"),
4706 depending the information provided by your boot server:
4708 bootfile - see above
4709 dnsip - IP address of your Domain Name Server
4710 dnsip2 - IP address of your secondary Domain Name Server
4711 gatewayip - IP address of the Gateway (Router) to use
4712 hostname - Target hostname
4714 netmask - Subnet Mask
4715 rootpath - Pathname of the root filesystem on the NFS server
4716 serverip - see above
4719 There are two special Environment Variables:
4721 serial# - contains hardware identification information such
4722 as type string and/or serial number
4723 ethaddr - Ethernet address
4725 These variables can be set only once (usually during manufacturing of
4726 the board). U-Boot refuses to delete or overwrite these variables
4727 once they have been set once.
4730 Further special Environment Variables:
4732 ver - Contains the U-Boot version string as printed
4733 with the "version" command. This variable is
4734 readonly (see CONFIG_VERSION_VARIABLE).
4737 Please note that changes to some configuration parameters may take
4738 only effect after the next boot (yes, that's just like Windoze :-).
4741 Callback functions for environment variables:
4742 ---------------------------------------------
4744 For some environment variables, the behavior of u-boot needs to change
4745 when their values are changed. This functionailty allows functions to
4746 be associated with arbitrary variables. On creation, overwrite, or
4747 deletion, the callback will provide the opportunity for some side
4748 effect to happen or for the change to be rejected.
4750 The callbacks are named and associated with a function using the
4751 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4753 These callbacks are associated with variables in one of two ways. The
4754 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4755 in the board configuration to a string that defines a list of
4756 associations. The list must be in the following format:
4758 entry = variable_name[:callback_name]
4761 If the callback name is not specified, then the callback is deleted.
4762 Spaces are also allowed anywhere in the list.
4764 Callbacks can also be associated by defining the ".callbacks" variable
4765 with the same list format above. Any association in ".callbacks" will
4766 override any association in the static list. You can define
4767 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4768 ".callbacks" envirnoment variable in the default or embedded environment.
4771 Command Line Parsing:
4772 =====================
4774 There are two different command line parsers available with U-Boot:
4775 the old "simple" one, and the much more powerful "hush" shell:
4777 Old, simple command line parser:
4778 --------------------------------
4780 - supports environment variables (through setenv / saveenv commands)
4781 - several commands on one line, separated by ';'
4782 - variable substitution using "... ${name} ..." syntax
4783 - special characters ('$', ';') can be escaped by prefixing with '\',
4785 setenv bootcmd bootm \${address}
4786 - You can also escape text by enclosing in single apostrophes, for example:
4787 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4792 - similar to Bourne shell, with control structures like
4793 if...then...else...fi, for...do...done; while...do...done,
4794 until...do...done, ...
4795 - supports environment ("global") variables (through setenv / saveenv
4796 commands) and local shell variables (through standard shell syntax
4797 "name=value"); only environment variables can be used with "run"
4803 (1) If a command line (or an environment variable executed by a "run"
4804 command) contains several commands separated by semicolon, and
4805 one of these commands fails, then the remaining commands will be
4808 (2) If you execute several variables with one call to run (i. e.
4809 calling run with a list of variables as arguments), any failing
4810 command will cause "run" to terminate, i. e. the remaining
4811 variables are not executed.
4813 Note for Redundant Ethernet Interfaces:
4814 =======================================
4816 Some boards come with redundant Ethernet interfaces; U-Boot supports
4817 such configurations and is capable of automatic selection of a
4818 "working" interface when needed. MAC assignment works as follows:
4820 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4821 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4822 "eth1addr" (=>eth1), "eth2addr", ...
4824 If the network interface stores some valid MAC address (for instance
4825 in SROM), this is used as default address if there is NO correspon-
4826 ding setting in the environment; if the corresponding environment
4827 variable is set, this overrides the settings in the card; that means:
4829 o If the SROM has a valid MAC address, and there is no address in the
4830 environment, the SROM's address is used.
4832 o If there is no valid address in the SROM, and a definition in the
4833 environment exists, then the value from the environment variable is
4836 o If both the SROM and the environment contain a MAC address, and
4837 both addresses are the same, this MAC address is used.
4839 o If both the SROM and the environment contain a MAC address, and the
4840 addresses differ, the value from the environment is used and a
4843 o If neither SROM nor the environment contain a MAC address, an error
4846 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4847 will be programmed into hardware as part of the initialization process. This
4848 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4849 The naming convention is as follows:
4850 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4855 U-Boot is capable of booting (and performing other auxiliary operations on)
4856 images in two formats:
4858 New uImage format (FIT)
4859 -----------------------
4861 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4862 to Flattened Device Tree). It allows the use of images with multiple
4863 components (several kernels, ramdisks, etc.), with contents protected by
4864 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4870 Old image format is based on binary files which can be basically anything,
4871 preceded by a special header; see the definitions in include/image.h for
4872 details; basically, the header defines the following image properties:
4874 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4875 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4876 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4877 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4879 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4880 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4881 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4882 * Compression Type (uncompressed, gzip, bzip2)
4888 The header is marked by a special Magic Number, and both the header
4889 and the data portions of the image are secured against corruption by
4896 Although U-Boot should support any OS or standalone application
4897 easily, the main focus has always been on Linux during the design of
4900 U-Boot includes many features that so far have been part of some
4901 special "boot loader" code within the Linux kernel. Also, any
4902 "initrd" images to be used are no longer part of one big Linux image;
4903 instead, kernel and "initrd" are separate images. This implementation
4904 serves several purposes:
4906 - the same features can be used for other OS or standalone
4907 applications (for instance: using compressed images to reduce the
4908 Flash memory footprint)
4910 - it becomes much easier to port new Linux kernel versions because
4911 lots of low-level, hardware dependent stuff are done by U-Boot
4913 - the same Linux kernel image can now be used with different "initrd"
4914 images; of course this also means that different kernel images can
4915 be run with the same "initrd". This makes testing easier (you don't
4916 have to build a new "zImage.initrd" Linux image when you just
4917 change a file in your "initrd"). Also, a field-upgrade of the
4918 software is easier now.
4924 Porting Linux to U-Boot based systems:
4925 ---------------------------------------
4927 U-Boot cannot save you from doing all the necessary modifications to
4928 configure the Linux device drivers for use with your target hardware
4929 (no, we don't intend to provide a full virtual machine interface to
4932 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4934 Just make sure your machine specific header file (for instance
4935 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4936 Information structure as we define in include/asm-<arch>/u-boot.h,
4937 and make sure that your definition of IMAP_ADDR uses the same value
4938 as your U-Boot configuration in CONFIG_SYS_IMMR.
4941 Configuring the Linux kernel:
4942 -----------------------------
4944 No specific requirements for U-Boot. Make sure you have some root
4945 device (initial ramdisk, NFS) for your target system.
4948 Building a Linux Image:
4949 -----------------------
4951 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4952 not used. If you use recent kernel source, a new build target
4953 "uImage" will exist which automatically builds an image usable by
4954 U-Boot. Most older kernels also have support for a "pImage" target,
4955 which was introduced for our predecessor project PPCBoot and uses a
4956 100% compatible format.
4965 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4966 encapsulate a compressed Linux kernel image with header information,
4967 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4969 * build a standard "vmlinux" kernel image (in ELF binary format):
4971 * convert the kernel into a raw binary image:
4973 ${CROSS_COMPILE}-objcopy -O binary \
4974 -R .note -R .comment \
4975 -S vmlinux linux.bin
4977 * compress the binary image:
4981 * package compressed binary image for U-Boot:
4983 mkimage -A ppc -O linux -T kernel -C gzip \
4984 -a 0 -e 0 -n "Linux Kernel Image" \
4985 -d linux.bin.gz uImage
4988 The "mkimage" tool can also be used to create ramdisk images for use
4989 with U-Boot, either separated from the Linux kernel image, or
4990 combined into one file. "mkimage" encapsulates the images with a 64
4991 byte header containing information about target architecture,
4992 operating system, image type, compression method, entry points, time
4993 stamp, CRC32 checksums, etc.
4995 "mkimage" can be called in two ways: to verify existing images and
4996 print the header information, or to build new images.
4998 In the first form (with "-l" option) mkimage lists the information
4999 contained in the header of an existing U-Boot image; this includes
5000 checksum verification:
5002 tools/mkimage -l image
5003 -l ==> list image header information
5005 The second form (with "-d" option) is used to build a U-Boot image
5006 from a "data file" which is used as image payload:
5008 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5009 -n name -d data_file image
5010 -A ==> set architecture to 'arch'
5011 -O ==> set operating system to 'os'
5012 -T ==> set image type to 'type'
5013 -C ==> set compression type 'comp'
5014 -a ==> set load address to 'addr' (hex)
5015 -e ==> set entry point to 'ep' (hex)
5016 -n ==> set image name to 'name'
5017 -d ==> use image data from 'datafile'
5019 Right now, all Linux kernels for PowerPC systems use the same load
5020 address (0x00000000), but the entry point address depends on the
5023 - 2.2.x kernels have the entry point at 0x0000000C,
5024 - 2.3.x and later kernels have the entry point at 0x00000000.
5026 So a typical call to build a U-Boot image would read:
5028 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5029 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5030 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5031 > examples/uImage.TQM850L
5032 Image Name: 2.4.4 kernel for TQM850L
5033 Created: Wed Jul 19 02:34:59 2000
5034 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5035 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5036 Load Address: 0x00000000
5037 Entry Point: 0x00000000
5039 To verify the contents of the image (or check for corruption):
5041 -> tools/mkimage -l examples/uImage.TQM850L
5042 Image Name: 2.4.4 kernel for TQM850L
5043 Created: Wed Jul 19 02:34:59 2000
5044 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5045 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5046 Load Address: 0x00000000
5047 Entry Point: 0x00000000
5049 NOTE: for embedded systems where boot time is critical you can trade
5050 speed for memory and install an UNCOMPRESSED image instead: this
5051 needs more space in Flash, but boots much faster since it does not
5052 need to be uncompressed:
5054 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5055 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5056 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5057 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5058 > examples/uImage.TQM850L-uncompressed
5059 Image Name: 2.4.4 kernel for TQM850L
5060 Created: Wed Jul 19 02:34:59 2000
5061 Image Type: PowerPC Linux Kernel Image (uncompressed)
5062 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5063 Load Address: 0x00000000
5064 Entry Point: 0x00000000
5067 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5068 when your kernel is intended to use an initial ramdisk:
5070 -> tools/mkimage -n 'Simple Ramdisk Image' \
5071 > -A ppc -O linux -T ramdisk -C gzip \
5072 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5073 Image Name: Simple Ramdisk Image
5074 Created: Wed Jan 12 14:01:50 2000
5075 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5076 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5077 Load Address: 0x00000000
5078 Entry Point: 0x00000000
5081 Installing a Linux Image:
5082 -------------------------
5084 To downloading a U-Boot image over the serial (console) interface,
5085 you must convert the image to S-Record format:
5087 objcopy -I binary -O srec examples/image examples/image.srec
5089 The 'objcopy' does not understand the information in the U-Boot
5090 image header, so the resulting S-Record file will be relative to
5091 address 0x00000000. To load it to a given address, you need to
5092 specify the target address as 'offset' parameter with the 'loads'
5095 Example: install the image to address 0x40100000 (which on the
5096 TQM8xxL is in the first Flash bank):
5098 => erase 40100000 401FFFFF
5104 ## Ready for S-Record download ...
5105 ~>examples/image.srec
5106 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5108 15989 15990 15991 15992
5109 [file transfer complete]
5111 ## Start Addr = 0x00000000
5114 You can check the success of the download using the 'iminfo' command;
5115 this includes a checksum verification so you can be sure no data
5116 corruption happened:
5120 ## Checking Image at 40100000 ...
5121 Image Name: 2.2.13 for initrd on TQM850L
5122 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5123 Data Size: 335725 Bytes = 327 kB = 0 MB
5124 Load Address: 00000000
5125 Entry Point: 0000000c
5126 Verifying Checksum ... OK
5132 The "bootm" command is used to boot an application that is stored in
5133 memory (RAM or Flash). In case of a Linux kernel image, the contents
5134 of the "bootargs" environment variable is passed to the kernel as
5135 parameters. You can check and modify this variable using the
5136 "printenv" and "setenv" commands:
5139 => printenv bootargs
5140 bootargs=root=/dev/ram
5142 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5144 => printenv bootargs
5145 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5148 ## Booting Linux kernel at 40020000 ...
5149 Image Name: 2.2.13 for NFS on TQM850L
5150 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5151 Data Size: 381681 Bytes = 372 kB = 0 MB
5152 Load Address: 00000000
5153 Entry Point: 0000000c
5154 Verifying Checksum ... OK
5155 Uncompressing Kernel Image ... OK
5156 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
5157 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5158 time_init: decrementer frequency = 187500000/60
5159 Calibrating delay loop... 49.77 BogoMIPS
5160 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5163 If you want to boot a Linux kernel with initial RAM disk, you pass
5164 the memory addresses of both the kernel and the initrd image (PPBCOOT
5165 format!) to the "bootm" command:
5167 => imi 40100000 40200000
5169 ## Checking Image at 40100000 ...
5170 Image Name: 2.2.13 for initrd on TQM850L
5171 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5172 Data Size: 335725 Bytes = 327 kB = 0 MB
5173 Load Address: 00000000
5174 Entry Point: 0000000c
5175 Verifying Checksum ... OK
5177 ## Checking Image at 40200000 ...
5178 Image Name: Simple Ramdisk Image
5179 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5180 Data Size: 566530 Bytes = 553 kB = 0 MB
5181 Load Address: 00000000
5182 Entry Point: 00000000
5183 Verifying Checksum ... OK
5185 => bootm 40100000 40200000
5186 ## Booting Linux kernel at 40100000 ...
5187 Image Name: 2.2.13 for initrd on TQM850L
5188 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5189 Data Size: 335725 Bytes = 327 kB = 0 MB
5190 Load Address: 00000000
5191 Entry Point: 0000000c
5192 Verifying Checksum ... OK
5193 Uncompressing Kernel Image ... OK
5194 ## Loading RAMDisk Image at 40200000 ...
5195 Image Name: Simple Ramdisk Image
5196 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5197 Data Size: 566530 Bytes = 553 kB = 0 MB
5198 Load Address: 00000000
5199 Entry Point: 00000000
5200 Verifying Checksum ... OK
5201 Loading Ramdisk ... OK
5202 Linux version 2.2.13 (
[email protected]) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
5203 Boot arguments: root=/dev/ram
5204 time_init: decrementer frequency = 187500000/60
5205 Calibrating delay loop... 49.77 BogoMIPS
5207 RAMDISK: Compressed image found at block 0
5208 VFS: Mounted root (ext2 filesystem).
5212 Boot Linux and pass a flat device tree:
5215 First, U-Boot must be compiled with the appropriate defines. See the section
5216 titled "Linux Kernel Interface" above for a more in depth explanation. The
5217 following is an example of how to start a kernel and pass an updated
5223 oft=oftrees/mpc8540ads.dtb
5224 => tftp $oftaddr $oft
5225 Speed: 1000, full duplex
5227 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5228 Filename 'oftrees/mpc8540ads.dtb'.
5229 Load address: 0x300000
5232 Bytes transferred = 4106 (100a hex)
5233 => tftp $loadaddr $bootfile
5234 Speed: 1000, full duplex
5236 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5238 Load address: 0x200000
5239 Loading:############
5241 Bytes transferred = 1029407 (fb51f hex)
5246 => bootm $loadaddr - $oftaddr
5247 ## Booting image at 00200000 ...
5248 Image Name: Linux-2.6.17-dirty
5249 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5250 Data Size: 1029343 Bytes = 1005.2 kB
5251 Load Address: 00000000
5252 Entry Point: 00000000
5253 Verifying Checksum ... OK
5254 Uncompressing Kernel Image ... OK
5255 Booting using flat device tree at 0x300000
5256 Using MPC85xx ADS machine description
5257 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5261 More About U-Boot Image Types:
5262 ------------------------------
5264 U-Boot supports the following image types:
5266 "Standalone Programs" are directly runnable in the environment
5267 provided by U-Boot; it is expected that (if they behave
5268 well) you can continue to work in U-Boot after return from
5269 the Standalone Program.
5270 "OS Kernel Images" are usually images of some Embedded OS which
5271 will take over control completely. Usually these programs
5272 will install their own set of exception handlers, device
5273 drivers, set up the MMU, etc. - this means, that you cannot
5274 expect to re-enter U-Boot except by resetting the CPU.
5275 "RAMDisk Images" are more or less just data blocks, and their
5276 parameters (address, size) are passed to an OS kernel that is
5278 "Multi-File Images" contain several images, typically an OS
5279 (Linux) kernel image and one or more data images like
5280 RAMDisks. This construct is useful for instance when you want
5281 to boot over the network using BOOTP etc., where the boot
5282 server provides just a single image file, but you want to get
5283 for instance an OS kernel and a RAMDisk image.
5285 "Multi-File Images" start with a list of image sizes, each
5286 image size (in bytes) specified by an "uint32_t" in network
5287 byte order. This list is terminated by an "(uint32_t)0".
5288 Immediately after the terminating 0 follow the images, one by
5289 one, all aligned on "uint32_t" boundaries (size rounded up to
5290 a multiple of 4 bytes).
5292 "Firmware Images" are binary images containing firmware (like
5293 U-Boot or FPGA images) which usually will be programmed to
5296 "Script files" are command sequences that will be executed by
5297 U-Boot's command interpreter; this feature is especially
5298 useful when you configure U-Boot to use a real shell (hush)
5299 as command interpreter.
5301 Booting the Linux zImage:
5302 -------------------------
5304 On some platforms, it's possible to boot Linux zImage. This is done
5305 using the "bootz" command. The syntax of "bootz" command is the same
5306 as the syntax of "bootm" command.
5308 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5309 kernel with raw initrd images. The syntax is slightly different, the
5310 address of the initrd must be augmented by it's size, in the following
5311 format: "<initrd addres>:<initrd size>".
5317 One of the features of U-Boot is that you can dynamically load and
5318 run "standalone" applications, which can use some resources of
5319 U-Boot like console I/O functions or interrupt services.
5321 Two simple examples are included with the sources:
5326 'examples/hello_world.c' contains a small "Hello World" Demo
5327 application; it is automatically compiled when you build U-Boot.
5328 It's configured to run at address 0x00040004, so you can play with it
5332 ## Ready for S-Record download ...
5333 ~>examples/hello_world.srec
5334 1 2 3 4 5 6 7 8 9 10 11 ...
5335 [file transfer complete]
5337 ## Start Addr = 0x00040004
5339 => go 40004 Hello World! This is a test.
5340 ## Starting application at 0x00040004 ...
5351 Hit any key to exit ...
5353 ## Application terminated, rc = 0x0
5355 Another example, which demonstrates how to register a CPM interrupt
5356 handler with the U-Boot code, can be found in 'examples/timer.c'.
5357 Here, a CPM timer is set up to generate an interrupt every second.
5358 The interrupt service routine is trivial, just printing a '.'
5359 character, but this is just a demo program. The application can be
5360 controlled by the following keys:
5362 ? - print current values og the CPM Timer registers
5363 b - enable interrupts and start timer
5364 e - stop timer and disable interrupts
5365 q - quit application
5368 ## Ready for S-Record download ...
5369 ~>examples/timer.srec
5370 1 2 3 4 5 6 7 8 9 10 11 ...
5371 [file transfer complete]
5373 ## Start Addr = 0x00040004
5376 ## Starting application at 0x00040004 ...
5379 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5382 [q, b, e, ?] Set interval 1000000 us
5385 [q, b, e, ?] ........
5386 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5389 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5392 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5395 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5397 [q, b, e, ?] ...Stopping timer
5399 [q, b, e, ?] ## Application terminated, rc = 0x0
5405 Over time, many people have reported problems when trying to use the
5406 "minicom" terminal emulation program for serial download. I (wd)
5407 consider minicom to be broken, and recommend not to use it. Under
5408 Unix, I recommend to use C-Kermit for general purpose use (and
5409 especially for kermit binary protocol download ("loadb" command), and
5410 use "cu" for S-Record download ("loads" command). See
5411 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5412 for help with kermit.
5415 Nevertheless, if you absolutely want to use it try adding this
5416 configuration to your "File transfer protocols" section:
5418 Name Program Name U/D FullScr IO-Red. Multi
5419 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5420 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5426 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5427 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5429 Building requires a cross environment; it is known to work on
5430 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5431 need gmake since the Makefiles are not compatible with BSD make).
5432 Note that the cross-powerpc package does not install include files;
5433 attempting to build U-Boot will fail because <machine/ansi.h> is
5434 missing. This file has to be installed and patched manually:
5436 # cd /usr/pkg/cross/powerpc-netbsd/include
5438 # ln -s powerpc machine
5439 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5440 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5442 Native builds *don't* work due to incompatibilities between native
5443 and U-Boot include files.
5445 Booting assumes that (the first part of) the image booted is a
5446 stage-2 loader which in turn loads and then invokes the kernel
5447 proper. Loader sources will eventually appear in the NetBSD source
5448 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5449 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5452 Implementation Internals:
5453 =========================
5455 The following is not intended to be a complete description of every
5456 implementation detail. However, it should help to understand the
5457 inner workings of U-Boot and make it easier to port it to custom
5461 Initial Stack, Global Data:
5462 ---------------------------
5464 The implementation of U-Boot is complicated by the fact that U-Boot
5465 starts running out of ROM (flash memory), usually without access to
5466 system RAM (because the memory controller is not initialized yet).
5467 This means that we don't have writable Data or BSS segments, and BSS
5468 is not initialized as zero. To be able to get a C environment working
5469 at all, we have to allocate at least a minimal stack. Implementation
5470 options for this are defined and restricted by the CPU used: Some CPU
5471 models provide on-chip memory (like the IMMR area on MPC8xx and
5472 MPC826x processors), on others (parts of) the data cache can be
5473 locked as (mis-) used as memory, etc.
5475 Chris Hallinan posted a good summary of these issues to the
5476 U-Boot mailing list:
5478 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5480 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5483 Correct me if I'm wrong, folks, but the way I understand it
5484 is this: Using DCACHE as initial RAM for Stack, etc, does not
5485 require any physical RAM backing up the cache. The cleverness
5486 is that the cache is being used as a temporary supply of
5487 necessary storage before the SDRAM controller is setup. It's
5488 beyond the scope of this list to explain the details, but you
5489 can see how this works by studying the cache architecture and
5490 operation in the architecture and processor-specific manuals.
5492 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5493 is another option for the system designer to use as an
5494 initial stack/RAM area prior to SDRAM being available. Either
5495 option should work for you. Using CS 4 should be fine if your
5496 board designers haven't used it for something that would
5497 cause you grief during the initial boot! It is frequently not
5500 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5501 with your processor/board/system design. The default value
5502 you will find in any recent u-boot distribution in
5503 walnut.h should work for you. I'd set it to a value larger
5504 than your SDRAM module. If you have a 64MB SDRAM module, set
5505 it above 400_0000. Just make sure your board has no resources
5506 that are supposed to respond to that address! That code in
5507 start.S has been around a while and should work as is when
5508 you get the config right.
5513 It is essential to remember this, since it has some impact on the C
5514 code for the initialization procedures:
5516 * Initialized global data (data segment) is read-only. Do not attempt
5519 * Do not use any uninitialized global data (or implicitely initialized
5520 as zero data - BSS segment) at all - this is undefined, initiali-
5521 zation is performed later (when relocating to RAM).
5523 * Stack space is very limited. Avoid big data buffers or things like
5526 Having only the stack as writable memory limits means we cannot use
5527 normal global data to share information beween the code. But it
5528 turned out that the implementation of U-Boot can be greatly
5529 simplified by making a global data structure (gd_t) available to all
5530 functions. We could pass a pointer to this data as argument to _all_
5531 functions, but this would bloat the code. Instead we use a feature of
5532 the GCC compiler (Global Register Variables) to share the data: we
5533 place a pointer (gd) to the global data into a register which we
5534 reserve for this purpose.
5536 When choosing a register for such a purpose we are restricted by the
5537 relevant (E)ABI specifications for the current architecture, and by
5538 GCC's implementation.
5540 For PowerPC, the following registers have specific use:
5542 R2: reserved for system use
5543 R3-R4: parameter passing and return values
5544 R5-R10: parameter passing
5545 R13: small data area pointer
5549 (U-Boot also uses R12 as internal GOT pointer. r12
5550 is a volatile register so r12 needs to be reset when
5551 going back and forth between asm and C)
5553 ==> U-Boot will use R2 to hold a pointer to the global data
5555 Note: on PPC, we could use a static initializer (since the
5556 address of the global data structure is known at compile time),
5557 but it turned out that reserving a register results in somewhat
5558 smaller code - although the code savings are not that big (on
5559 average for all boards 752 bytes for the whole U-Boot image,
5560 624 text + 127 data).
5562 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5563 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5565 ==> U-Boot will use P3 to hold a pointer to the global data
5567 On ARM, the following registers are used:
5569 R0: function argument word/integer result
5570 R1-R3: function argument word
5572 R10: stack limit (used only if stack checking if enabled)
5573 R11: argument (frame) pointer
5574 R12: temporary workspace
5577 R15: program counter
5579 ==> U-Boot will use R8 to hold a pointer to the global data
5581 On Nios II, the ABI is documented here:
5582 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5584 ==> U-Boot will use gp to hold a pointer to the global data
5586 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5587 to access small data sections, so gp is free.
5589 On NDS32, the following registers are used:
5591 R0-R1: argument/return
5593 R15: temporary register for assembler
5594 R16: trampoline register
5595 R28: frame pointer (FP)
5596 R29: global pointer (GP)
5597 R30: link register (LP)
5598 R31: stack pointer (SP)
5599 PC: program counter (PC)
5601 ==> U-Boot will use R10 to hold a pointer to the global data
5603 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5604 or current versions of GCC may "optimize" the code too much.
5609 U-Boot runs in system state and uses physical addresses, i.e. the
5610 MMU is not used either for address mapping nor for memory protection.
5612 The available memory is mapped to fixed addresses using the memory
5613 controller. In this process, a contiguous block is formed for each
5614 memory type (Flash, SDRAM, SRAM), even when it consists of several
5615 physical memory banks.
5617 U-Boot is installed in the first 128 kB of the first Flash bank (on
5618 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5619 booting and sizing and initializing DRAM, the code relocates itself
5620 to the upper end of DRAM. Immediately below the U-Boot code some
5621 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5622 configuration setting]. Below that, a structure with global Board
5623 Info data is placed, followed by the stack (growing downward).
5625 Additionally, some exception handler code is copied to the low 8 kB
5626 of DRAM (0x00000000 ... 0x00001FFF).
5628 So a typical memory configuration with 16 MB of DRAM could look like
5631 0x0000 0000 Exception Vector code
5634 0x0000 2000 Free for Application Use
5640 0x00FB FF20 Monitor Stack (Growing downward)
5641 0x00FB FFAC Board Info Data and permanent copy of global data
5642 0x00FC 0000 Malloc Arena
5645 0x00FE 0000 RAM Copy of Monitor Code
5646 ... eventually: LCD or video framebuffer
5647 ... eventually: pRAM (Protected RAM - unchanged by reset)
5648 0x00FF FFFF [End of RAM]
5651 System Initialization:
5652 ----------------------
5654 In the reset configuration, U-Boot starts at the reset entry point
5655 (on most PowerPC systems at address 0x00000100). Because of the reset
5656 configuration for CS0# this is a mirror of the onboard Flash memory.
5657 To be able to re-map memory U-Boot then jumps to its link address.
5658 To be able to implement the initialization code in C, a (small!)
5659 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5660 which provide such a feature like MPC8xx or MPC8260), or in a locked
5661 part of the data cache. After that, U-Boot initializes the CPU core,
5662 the caches and the SIU.
5664 Next, all (potentially) available memory banks are mapped using a
5665 preliminary mapping. For example, we put them on 512 MB boundaries
5666 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5667 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5668 programmed for SDRAM access. Using the temporary configuration, a
5669 simple memory test is run that determines the size of the SDRAM
5672 When there is more than one SDRAM bank, and the banks are of
5673 different size, the largest is mapped first. For equal size, the first
5674 bank (CS2#) is mapped first. The first mapping is always for address
5675 0x00000000, with any additional banks following immediately to create
5676 contiguous memory starting from 0.
5678 Then, the monitor installs itself at the upper end of the SDRAM area
5679 and allocates memory for use by malloc() and for the global Board
5680 Info data; also, the exception vector code is copied to the low RAM
5681 pages, and the final stack is set up.
5683 Only after this relocation will you have a "normal" C environment;
5684 until that you are restricted in several ways, mostly because you are
5685 running from ROM, and because the code will have to be relocated to a
5689 U-Boot Porting Guide:
5690 ----------------------
5692 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5696 int main(int argc, char *argv[])
5698 sighandler_t no_more_time;
5700 signal(SIGALRM, no_more_time);
5701 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5703 if (available_money > available_manpower) {
5704 Pay consultant to port U-Boot;
5708 Download latest U-Boot source;
5710 Subscribe to u-boot mailing list;
5713 email("Hi, I am new to U-Boot, how do I get started?");
5716 Read the README file in the top level directory;
5717 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5718 Read applicable doc/*.README;
5719 Read the source, Luke;
5720 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5723 if (available_money > toLocalCurrency ($2500))
5726 Add a lot of aggravation and time;
5728 if (a similar board exists) { /* hopefully... */
5729 cp -a board/<similar> board/<myboard>
5730 cp include/configs/<similar>.h include/configs/<myboard>.h
5732 Create your own board support subdirectory;
5733 Create your own board include/configs/<myboard>.h file;
5735 Edit new board/<myboard> files
5736 Edit new include/configs/<myboard>.h
5741 Add / modify source code;
5745 email("Hi, I am having problems...");
5747 Send patch file to the U-Boot email list;
5748 if (reasonable critiques)
5749 Incorporate improvements from email list code review;
5751 Defend code as written;
5757 void no_more_time (int sig)
5766 All contributions to U-Boot should conform to the Linux kernel
5767 coding style; see the file "Documentation/CodingStyle" and the script
5768 "scripts/Lindent" in your Linux kernel source directory.
5770 Source files originating from a different project (for example the
5771 MTD subsystem) are generally exempt from these guidelines and are not
5772 reformated to ease subsequent migration to newer versions of those
5775 Please note that U-Boot is implemented in C (and to some small parts in
5776 Assembler); no C++ is used, so please do not use C++ style comments (//)
5779 Please also stick to the following formatting rules:
5780 - remove any trailing white space
5781 - use TAB characters for indentation and vertical alignment, not spaces
5782 - make sure NOT to use DOS '\r\n' line feeds
5783 - do not add more than 2 consecutive empty lines to source files
5784 - do not add trailing empty lines to source files
5786 Submissions which do not conform to the standards may be returned
5787 with a request to reformat the changes.
5793 Since the number of patches for U-Boot is growing, we need to
5794 establish some rules. Submissions which do not conform to these rules
5795 may be rejected, even when they contain important and valuable stuff.
5797 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5800 see http://lists.denx.de/mailman/listinfo/u-boot
5802 When you send a patch, please include the following information with
5805 * For bug fixes: a description of the bug and how your patch fixes
5806 this bug. Please try to include a way of demonstrating that the
5807 patch actually fixes something.
5809 * For new features: a description of the feature and your
5812 * A CHANGELOG entry as plaintext (separate from the patch)
5814 * For major contributions, your entry to the CREDITS file
5816 * When you add support for a new board, don't forget to add this
5817 board to the MAINTAINERS file, too.
5819 * If your patch adds new configuration options, don't forget to
5820 document these in the README file.
5822 * The patch itself. If you are using git (which is *strongly*
5823 recommended) you can easily generate the patch using the
5824 "git format-patch". If you then use "git send-email" to send it to
5825 the U-Boot mailing list, you will avoid most of the common problems
5826 with some other mail clients.
5828 If you cannot use git, use "diff -purN OLD NEW". If your version of
5829 diff does not support these options, then get the latest version of
5832 The current directory when running this command shall be the parent
5833 directory of the U-Boot source tree (i. e. please make sure that
5834 your patch includes sufficient directory information for the
5837 We prefer patches as plain text. MIME attachments are discouraged,
5838 and compressed attachments must not be used.
5840 * If one logical set of modifications affects or creates several
5841 files, all these changes shall be submitted in a SINGLE patch file.
5843 * Changesets that contain different, unrelated modifications shall be
5844 submitted as SEPARATE patches, one patch per changeset.
5849 * Before sending the patch, run the MAKEALL script on your patched
5850 source tree and make sure that no errors or warnings are reported
5851 for any of the boards.
5853 * Keep your modifications to the necessary minimum: A patch
5854 containing several unrelated changes or arbitrary reformats will be
5855 returned with a request to re-formatting / split it.
5857 * If you modify existing code, make sure that your new code does not
5858 add to the memory footprint of the code ;-) Small is beautiful!
5859 When adding new features, these should compile conditionally only
5860 (using #ifdef), and the resulting code with the new feature
5861 disabled must not need more memory than the old code without your
5864 * Remember that there is a size limit of 100 kB per message on the
5865 u-boot mailing list. Bigger patches will be moderated. If they are
5866 reasonable and not too big, they will be acknowledged. But patches
5867 bigger than the size limit should be avoided.
projects / u-boot.git / blob