2 # (C) Copyright 2000 - 2012
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
57 Note: There is no CHANGELOG file in the actual U-Boot source tree;
58 it can be created dynamically from the Git log using:
66 In case you have questions about, problems with or contributions for
67 U-Boot you should send a message to the U-Boot mailing list at
68 <u-boot@lists.denx.de>. There is also an archive of previous traffic
69 on the mailing list - please search the archive before asking FAQ's.
70 Please see http://lists.denx.de/pipermail/u-boot and
71 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
74 Where to get source code:
75 =========================
77 The U-Boot source code is maintained in the git repository at
78 git://www.denx.de/git/u-boot.git ; you can browse it online at
79 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
81 The "snapshot" links on this page allow you to download tarballs of
82 any version you might be interested in. Official releases are also
83 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
86 Pre-built (and tested) images are available from
87 ftp://ftp.denx.de/pub/u-boot/images/
93 - start from 8xxrom sources
94 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
96 - make it easier to add custom boards
97 - make it possible to add other [PowerPC] CPUs
98 - extend functions, especially:
99 * Provide extended interface to Linux boot loader
102 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
103 - create ARMBoot project (http://sourceforge.net/projects/armboot)
104 - add other CPU families (starting with ARM)
105 - create U-Boot project (http://sourceforge.net/projects/u-boot)
106 - current project page: see http://www.denx.de/wiki/U-Boot
112 The "official" name of this project is "Das U-Boot". The spelling
113 "U-Boot" shall be used in all written text (documentation, comments
114 in source files etc.). Example:
116 This is the README file for the U-Boot project.
118 File names etc. shall be based on the string "u-boot". Examples:
120 include/asm-ppc/u-boot.h
122 #include <asm/u-boot.h>
124 Variable names, preprocessor constants etc. shall be either based on
125 the string "u_boot" or on "U_BOOT". Example:
127 U_BOOT_VERSION u_boot_logo
128 IH_OS_U_BOOT u_boot_hush_start
134 Starting with the release in October 2008, the names of the releases
135 were changed from numerical release numbers without deeper meaning
136 into a time stamp based numbering. Regular releases are identified by
137 names consisting of the calendar year and month of the release date.
138 Additional fields (if present) indicate release candidates or bug fix
139 releases in "stable" maintenance trees.
142 U-Boot v2009.11 - Release November 2009
143 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
144 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
150 /arch Architecture specific files
151 /arm Files generic to ARM architecture
152 /cpu CPU specific files
153 /arm720t Files specific to ARM 720 CPUs
154 /arm920t Files specific to ARM 920 CPUs
155 /at91 Files specific to Atmel AT91RM9200 CPU
156 /imx Files specific to Freescale MC9328 i.MX CPUs
157 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
158 /arm925t Files specific to ARM 925 CPUs
159 /arm926ejs Files specific to ARM 926 CPUs
160 /arm1136 Files specific to ARM 1136 CPUs
161 /ixp Files specific to Intel XScale IXP CPUs
162 /pxa Files specific to Intel XScale PXA CPUs
163 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
164 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
165 /lib Architecture specific library files
166 /avr32 Files generic to AVR32 architecture
167 /cpu CPU specific files
168 /lib Architecture specific library files
169 /blackfin Files generic to Analog Devices Blackfin architecture
170 /cpu CPU specific files
171 /lib Architecture specific library files
172 /x86 Files generic to x86 architecture
173 /cpu CPU specific files
174 /lib Architecture specific library files
175 /m68k Files generic to m68k architecture
176 /cpu CPU specific files
177 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
178 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
179 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
180 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
181 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
182 /lib Architecture specific library files
183 /microblaze Files generic to microblaze architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /mips Files generic to MIPS architecture
187 /cpu CPU specific files
188 /mips32 Files specific to MIPS32 CPUs
189 /xburst Files specific to Ingenic XBurst CPUs
190 /lib Architecture specific library files
191 /nds32 Files generic to NDS32 architecture
192 /cpu CPU specific files
193 /n1213 Files specific to Andes Technology N1213 CPUs
194 /lib Architecture specific library files
195 /nios2 Files generic to Altera NIOS2 architecture
196 /cpu CPU specific files
197 /lib Architecture specific library files
198 /powerpc Files generic to PowerPC architecture
199 /cpu CPU specific files
200 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
201 /mpc5xx Files specific to Freescale MPC5xx CPUs
202 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
203 /mpc8xx Files specific to Freescale MPC8xx CPUs
204 /mpc8220 Files specific to Freescale MPC8220 CPUs
205 /mpc824x Files specific to Freescale MPC824x CPUs
206 /mpc8260 Files specific to Freescale MPC8260 CPUs
207 /mpc85xx Files specific to Freescale MPC85xx CPUs
208 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
209 /lib Architecture specific library files
210 /sh Files generic to SH architecture
211 /cpu CPU specific files
212 /sh2 Files specific to sh2 CPUs
213 /sh3 Files specific to sh3 CPUs
214 /sh4 Files specific to sh4 CPUs
215 /lib Architecture specific library files
216 /sparc Files generic to SPARC architecture
217 /cpu CPU specific files
218 /leon2 Files specific to Gaisler LEON2 SPARC CPU
219 /leon3 Files specific to Gaisler LEON3 SPARC CPU
220 /lib Architecture specific library files
221 /api Machine/arch independent API for external apps
222 /board Board dependent files
223 /common Misc architecture independent functions
224 /disk Code for disk drive partition handling
225 /doc Documentation (don't expect too much)
226 /drivers Commonly used device drivers
227 /examples Example code for standalone applications, etc.
228 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
229 /include Header Files
230 /lib Files generic to all architectures
231 /libfdt Library files to support flattened device trees
232 /lzma Library files to support LZMA decompression
233 /lzo Library files to support LZO decompression
235 /post Power On Self Test
236 /rtc Real Time Clock drivers
237 /tools Tools to build S-Record or U-Boot images, etc.
239 Software Configuration:
240 =======================
242 Configuration is usually done using C preprocessor defines; the
243 rationale behind that is to avoid dead code whenever possible.
245 There are two classes of configuration variables:
247 * Configuration _OPTIONS_:
248 These are selectable by the user and have names beginning with
251 * Configuration _SETTINGS_:
252 These depend on the hardware etc. and should not be meddled with if
253 you don't know what you're doing; they have names beginning with
256 Later we will add a configuration tool - probably similar to or even
257 identical to what's used for the Linux kernel. Right now, we have to
258 do the configuration by hand, which means creating some symbolic
259 links and editing some configuration files. We use the TQM8xxL boards
263 Selection of Processor Architecture and Board Type:
264 ---------------------------------------------------
266 For all supported boards there are ready-to-use default
267 configurations available; just type "make <board_name>_config".
269 Example: For a TQM823L module type:
274 For the Cogent platform, you need to specify the CPU type as well;
275 e.g. "make cogent_mpc8xx_config". And also configure the cogent
276 directory according to the instructions in cogent/README.
279 Configuration Options:
280 ----------------------
282 Configuration depends on the combination of board and CPU type; all
283 such information is kept in a configuration file
284 "include/configs/<board_name>.h".
286 Example: For a TQM823L module, all configuration settings are in
287 "include/configs/TQM823L.h".
290 Many of the options are named exactly as the corresponding Linux
291 kernel configuration options. The intention is to make it easier to
292 build a config tool - later.
295 The following options need to be configured:
297 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
299 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
301 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
302 Define exactly one, e.g. CONFIG_ATSTK1002
304 - CPU Module Type: (if CONFIG_COGENT is defined)
305 Define exactly one of
307 --- FIXME --- not tested yet:
308 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
309 CONFIG_CMA287_23, CONFIG_CMA287_50
311 - Motherboard Type: (if CONFIG_COGENT is defined)
312 Define exactly one of
313 CONFIG_CMA101, CONFIG_CMA102
315 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
316 Define one or more of
319 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
320 Define one or more of
321 CONFIG_LCD_HEARTBEAT - update a character position on
322 the LCD display every second with
325 - Board flavour: (if CONFIG_MPC8260ADS is defined)
328 CONFIG_SYS_8260ADS - original MPC8260ADS
329 CONFIG_SYS_8266ADS - MPC8266ADS
330 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
331 CONFIG_SYS_8272ADS - MPC8272ADS
333 - Marvell Family Member
334 CONFIG_SYS_MVFS - define it if you want to enable
335 multiple fs option at one time
336 for marvell soc family
338 - MPC824X Family Member (if CONFIG_MPC824X is defined)
339 Define exactly one of
340 CONFIG_MPC8240, CONFIG_MPC8245
342 - 8xx CPU Options: (if using an MPC8xx CPU)
343 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
344 get_gclk_freq() cannot work
345 e.g. if there is no 32KHz
346 reference PIT/RTC clock
347 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
350 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
351 CONFIG_SYS_8xx_CPUCLK_MIN
352 CONFIG_SYS_8xx_CPUCLK_MAX
353 CONFIG_8xx_CPUCLK_DEFAULT
354 See doc/README.MPC866
356 CONFIG_SYS_MEASURE_CPUCLK
358 Define this to measure the actual CPU clock instead
359 of relying on the correctness of the configured
360 values. Mostly useful for board bringup to make sure
361 the PLL is locked at the intended frequency. Note
362 that this requires a (stable) reference clock (32 kHz
363 RTC clock or CONFIG_SYS_8XX_XIN)
365 CONFIG_SYS_DELAYED_ICACHE
367 Define this option if you want to enable the
368 ICache only when Code runs from RAM.
373 Specifies that the core is a 64-bit PowerPC implementation (implements
374 the "64" category of the Power ISA). This is necessary for ePAPR
375 compliance, among other possible reasons.
377 CONFIG_SYS_FSL_TBCLK_DIV
379 Defines the core time base clock divider ratio compared to the
380 system clock. On most PQ3 devices this is 8, on newer QorIQ
381 devices it can be 16 or 32. The ratio varies from SoC to Soc.
383 CONFIG_SYS_FSL_PCIE_COMPAT
385 Defines the string to utilize when trying to match PCIe device
386 tree nodes for the given platform.
388 CONFIG_SYS_PPC_E500_DEBUG_TLB
390 Enables a temporary TLB entry to be used during boot to work
391 around limitations in e500v1 and e500v2 external debugger
392 support. This reduces the portions of the boot code where
393 breakpoints and single stepping do not work. The value of this
394 symbol should be set to the TLB1 entry to be used for this
397 CONFIG_SYS_FSL_ERRATUM_A004510
399 Enables a workaround for erratum A004510. If set,
400 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
401 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
404 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
406 Defines one or two SoC revisions (low 8 bits of SVR)
407 for which the A004510 workaround should be applied.
409 The rest of SVR is either not relevant to the decision
410 of whether the erratum is present (e.g. p2040 versus
411 p2041) or is implied by the build target, which controls
412 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
414 See Freescale App Note 4493 for more information about
417 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
419 This is the value to write into CCSR offset 0x18600
420 according to the A004510 workaround.
422 - Generic CPU options:
423 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
425 Defines the endianess of the CPU. Implementation of those
426 values is arch specific.
428 - Intel Monahans options:
429 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
431 Defines the Monahans run mode to oscillator
432 ratio. Valid values are 8, 16, 24, 31. The core
433 frequency is this value multiplied by 13 MHz.
435 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
437 Defines the Monahans turbo mode to oscillator
438 ratio. Valid values are 1 (default if undefined) and
439 2. The core frequency as calculated above is multiplied
443 CONFIG_SYS_INIT_SP_OFFSET
445 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
446 pointer. This is needed for the temporary stack before
449 CONFIG_SYS_MIPS_CACHE_MODE
451 Cache operation mode for the MIPS CPU.
452 See also arch/mips/include/asm/mipsregs.h.
454 CONF_CM_CACHABLE_NO_WA
457 CONF_CM_CACHABLE_NONCOHERENT
461 CONF_CM_CACHABLE_ACCELERATED
463 CONFIG_SYS_XWAY_EBU_BOOTCFG
465 Special option for Lantiq XWAY SoCs for booting from NOR flash.
466 See also arch/mips/cpu/mips32/start.S.
468 CONFIG_XWAY_SWAP_BYTES
470 Enable compilation of tools/xway-swap-bytes needed for Lantiq
471 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
472 be swapped if a flash programmer is used.
475 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
477 Select high exception vectors of the ARM core, e.g., do not
478 clear the V bit of the c1 register of CP15.
480 CONFIG_SYS_THUMB_BUILD
482 Use this flag to build U-Boot using the Thumb instruction
483 set for ARM architectures. Thumb instruction set provides
484 better code density. For ARM architectures that support
485 Thumb2 this flag will result in Thumb2 code generated by
488 CONFIG_ARM_ERRATA_716044
489 CONFIG_ARM_ERRATA_742230
490 CONFIG_ARM_ERRATA_743622
491 CONFIG_ARM_ERRATA_751472
493 If set, the workarounds for these ARM errata are applied early
494 during U-Boot startup. Note that these options force the
495 workarounds to be applied; no CPU-type/version detection
496 exists, unlike the similar options in the Linux kernel. Do not
497 set these options unless they apply!
502 The frequency of the timer returned by get_timer().
503 get_timer() must operate in milliseconds and this CONFIG
504 option must be set to 1000.
506 - Linux Kernel Interface:
509 U-Boot stores all clock information in Hz
510 internally. For binary compatibility with older Linux
511 kernels (which expect the clocks passed in the
512 bd_info data to be in MHz) the environment variable
513 "clocks_in_mhz" can be defined so that U-Boot
514 converts clock data to MHZ before passing it to the
516 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
517 "clocks_in_mhz=1" is automatically included in the
520 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
522 When transferring memsize parameter to linux, some versions
523 expect it to be in bytes, others in MB.
524 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
528 New kernel versions are expecting firmware settings to be
529 passed using flattened device trees (based on open firmware
533 * New libfdt-based support
534 * Adds the "fdt" command
535 * The bootm command automatically updates the fdt
537 OF_CPU - The proper name of the cpus node (only required for
538 MPC512X and MPC5xxx based boards).
539 OF_SOC - The proper name of the soc node (only required for
540 MPC512X and MPC5xxx based boards).
541 OF_TBCLK - The timebase frequency.
542 OF_STDOUT_PATH - The path to the console device
544 boards with QUICC Engines require OF_QE to set UCC MAC
547 CONFIG_OF_BOARD_SETUP
549 Board code has addition modification that it wants to make
550 to the flat device tree before handing it off to the kernel
554 This define fills in the correct boot CPU in the boot
555 param header, the default value is zero if undefined.
559 U-Boot can detect if an IDE device is present or not.
560 If not, and this new config option is activated, U-Boot
561 removes the ATA node from the DTS before booting Linux,
562 so the Linux IDE driver does not probe the device and
563 crash. This is needed for buggy hardware (uc101) where
564 no pull down resistor is connected to the signal IDE5V_DD7.
566 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
568 This setting is mandatory for all boards that have only one
569 machine type and must be used to specify the machine type
570 number as it appears in the ARM machine registry
571 (see http://www.arm.linux.org.uk/developer/machines/).
572 Only boards that have multiple machine types supported
573 in a single configuration file and the machine type is
574 runtime discoverable, do not have to use this setting.
576 - vxWorks boot parameters:
578 bootvx constructs a valid bootline using the following
579 environments variables: bootfile, ipaddr, serverip, hostname.
580 It loads the vxWorks image pointed bootfile.
582 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
583 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
584 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
585 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
587 CONFIG_SYS_VXWORKS_ADD_PARAMS
589 Add it at the end of the bootline. E.g "u=username pw=secret"
591 Note: If a "bootargs" environment is defined, it will overwride
592 the defaults discussed just above.
594 - Cache Configuration:
595 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
596 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
597 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
599 - Cache Configuration for ARM:
600 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
602 CONFIG_SYS_PL310_BASE - Physical base address of PL310
603 controller register space
608 Define this if you want support for Amba PrimeCell PL010 UARTs.
612 Define this if you want support for Amba PrimeCell PL011 UARTs.
616 If you have Amba PrimeCell PL011 UARTs, set this variable to
617 the clock speed of the UARTs.
621 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
622 define this to a list of base addresses for each (supported)
623 port. See e.g. include/configs/versatile.h
625 CONFIG_PL011_SERIAL_RLCR
627 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
628 have separate receive and transmit line control registers. Set
629 this variable to initialize the extra register.
631 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
633 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
634 boot loader that has already initialized the UART. Define this
635 variable to flush the UART at init time.
639 Depending on board, define exactly one serial port
640 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
641 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
642 console by defining CONFIG_8xx_CONS_NONE
644 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
645 port routines must be defined elsewhere
646 (i.e. serial_init(), serial_getc(), ...)
649 Enables console device for a color framebuffer. Needs following
650 defines (cf. smiLynxEM, i8042)
651 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
653 VIDEO_HW_RECTFILL graphic chip supports
656 VIDEO_HW_BITBLT graphic chip supports
657 bit-blit (cf. smiLynxEM)
658 VIDEO_VISIBLE_COLS visible pixel columns
660 VIDEO_VISIBLE_ROWS visible pixel rows
661 VIDEO_PIXEL_SIZE bytes per pixel
662 VIDEO_DATA_FORMAT graphic data format
663 (0-5, cf. cfb_console.c)
664 VIDEO_FB_ADRS framebuffer address
665 VIDEO_KBD_INIT_FCT keyboard int fct
666 (i.e. i8042_kbd_init())
667 VIDEO_TSTC_FCT test char fct
669 VIDEO_GETC_FCT get char fct
671 CONFIG_CONSOLE_CURSOR cursor drawing on/off
672 (requires blink timer
674 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
675 CONFIG_CONSOLE_TIME display time/date info in
677 (requires CONFIG_CMD_DATE)
678 CONFIG_VIDEO_LOGO display Linux logo in
680 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
681 linux_logo.h for logo.
682 Requires CONFIG_VIDEO_LOGO
683 CONFIG_CONSOLE_EXTRA_INFO
684 additional board info beside
687 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
688 a limited number of ANSI escape sequences (cursor control,
689 erase functions and limited graphics rendition control).
691 When CONFIG_CFB_CONSOLE is defined, video console is
692 default i/o. Serial console can be forced with
693 environment 'console=serial'.
695 When CONFIG_SILENT_CONSOLE is defined, all console
696 messages (by U-Boot and Linux!) can be silenced with
697 the "silent" environment variable. See
698 doc/README.silent for more information.
701 CONFIG_BAUDRATE - in bps
702 Select one of the baudrates listed in
703 CONFIG_SYS_BAUDRATE_TABLE, see below.
704 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
706 - Console Rx buffer length
707 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
708 the maximum receive buffer length for the SMC.
709 This option is actual only for 82xx and 8xx possible.
710 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
711 must be defined, to setup the maximum idle timeout for
714 - Pre-Console Buffer:
715 Prior to the console being initialised (i.e. serial UART
716 initialised etc) all console output is silently discarded.
717 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
718 buffer any console messages prior to the console being
719 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
720 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
721 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
722 bytes are output before the console is initialised, the
723 earlier bytes are discarded.
725 'Sane' compilers will generate smaller code if
726 CONFIG_PRE_CON_BUF_SZ is a power of 2
728 - Safe printf() functions
729 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
730 the printf() functions. These are defined in
731 include/vsprintf.h and include snprintf(), vsnprintf() and
732 so on. Code size increase is approximately 300-500 bytes.
733 If this option is not given then these functions will
734 silently discard their buffer size argument - this means
735 you are not getting any overflow checking in this case.
737 - Boot Delay: CONFIG_BOOTDELAY - in seconds
738 Delay before automatically booting the default image;
739 set to -1 to disable autoboot.
740 set to -2 to autoboot with no delay and not check for abort
741 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
743 See doc/README.autoboot for these options that
744 work with CONFIG_BOOTDELAY. None are required.
745 CONFIG_BOOT_RETRY_TIME
746 CONFIG_BOOT_RETRY_MIN
747 CONFIG_AUTOBOOT_KEYED
748 CONFIG_AUTOBOOT_PROMPT
749 CONFIG_AUTOBOOT_DELAY_STR
750 CONFIG_AUTOBOOT_STOP_STR
751 CONFIG_AUTOBOOT_DELAY_STR2
752 CONFIG_AUTOBOOT_STOP_STR2
753 CONFIG_ZERO_BOOTDELAY_CHECK
754 CONFIG_RESET_TO_RETRY
758 Only needed when CONFIG_BOOTDELAY is enabled;
759 define a command string that is automatically executed
760 when no character is read on the console interface
761 within "Boot Delay" after reset.
764 This can be used to pass arguments to the bootm
765 command. The value of CONFIG_BOOTARGS goes into the
766 environment value "bootargs".
768 CONFIG_RAMBOOT and CONFIG_NFSBOOT
769 The value of these goes into the environment as
770 "ramboot" and "nfsboot" respectively, and can be used
771 as a convenience, when switching between booting from
777 When this option is #defined, the existence of the
778 environment variable "preboot" will be checked
779 immediately before starting the CONFIG_BOOTDELAY
780 countdown and/or running the auto-boot command resp.
781 entering interactive mode.
783 This feature is especially useful when "preboot" is
784 automatically generated or modified. For an example
785 see the LWMON board specific code: here "preboot" is
786 modified when the user holds down a certain
787 combination of keys on the (special) keyboard when
790 - Serial Download Echo Mode:
792 If defined to 1, all characters received during a
793 serial download (using the "loads" command) are
794 echoed back. This might be needed by some terminal
795 emulations (like "cu"), but may as well just take
796 time on others. This setting #define's the initial
797 value of the "loads_echo" environment variable.
799 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
801 Select one of the baudrates listed in
802 CONFIG_SYS_BAUDRATE_TABLE, see below.
805 Monitor commands can be included or excluded
806 from the build by using the #include files
807 <config_cmd_all.h> and #undef'ing unwanted
808 commands, or using <config_cmd_default.h>
809 and augmenting with additional #define's
812 The default command configuration includes all commands
813 except those marked below with a "*".
815 CONFIG_CMD_ASKENV * ask for env variable
816 CONFIG_CMD_BDI bdinfo
817 CONFIG_CMD_BEDBUG * Include BedBug Debugger
818 CONFIG_CMD_BMP * BMP support
819 CONFIG_CMD_BSP * Board specific commands
820 CONFIG_CMD_BOOTD bootd
821 CONFIG_CMD_CACHE * icache, dcache
822 CONFIG_CMD_CONSOLE coninfo
823 CONFIG_CMD_CRC32 * crc32
824 CONFIG_CMD_DATE * support for RTC, date/time...
825 CONFIG_CMD_DHCP * DHCP support
826 CONFIG_CMD_DIAG * Diagnostics
827 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
828 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
829 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
830 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
831 CONFIG_CMD_DTT * Digital Therm and Thermostat
832 CONFIG_CMD_ECHO echo arguments
833 CONFIG_CMD_EDITENV edit env variable
834 CONFIG_CMD_EEPROM * EEPROM read/write support
835 CONFIG_CMD_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
837 CONFIG_CMD_ENV_FLAGS * display details about env flags
838 CONFIG_CMD_EXPORTENV * export the environment
839 CONFIG_CMD_EXT2 * ext2 command support
840 CONFIG_CMD_EXT4 * ext4 command support
841 CONFIG_CMD_SAVEENV saveenv
842 CONFIG_CMD_FDC * Floppy Disk Support
843 CONFIG_CMD_FAT * FAT command support
844 CONFIG_CMD_FDOS * Dos diskette Support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GETTIME * Get time since boot
848 CONFIG_CMD_GO * the 'go' command (exec code)
849 CONFIG_CMD_GREPENV * search environment
850 CONFIG_CMD_HASH * calculate hash / digest
851 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
852 CONFIG_CMD_I2C * I2C serial bus support
853 CONFIG_CMD_IDE * IDE harddisk support
854 CONFIG_CMD_IMI iminfo
855 CONFIG_CMD_IMLS List all images found in NOR flash
856 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
857 CONFIG_CMD_IMMAP * IMMR dump support
858 CONFIG_CMD_IMPORTENV * import an environment
859 CONFIG_CMD_INI * import data from an ini file into the env
860 CONFIG_CMD_IRQ * irqinfo
861 CONFIG_CMD_ITEST Integer/string test of 2 values
862 CONFIG_CMD_JFFS2 * JFFS2 Support
863 CONFIG_CMD_KGDB * kgdb
864 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
865 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
867 CONFIG_CMD_LOADB loadb
868 CONFIG_CMD_LOADS loads
869 CONFIG_CMD_MD5SUM print md5 message digest
870 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
871 CONFIG_CMD_MEMINFO * Display detailed memory information
872 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
874 CONFIG_CMD_MEMTEST mtest
875 CONFIG_CMD_MISC Misc functions like sleep etc
876 CONFIG_CMD_MMC * MMC memory mapped support
877 CONFIG_CMD_MII * MII utility commands
878 CONFIG_CMD_MTDPARTS * MTD partition support
879 CONFIG_CMD_NAND * NAND support
880 CONFIG_CMD_NET bootp, tftpboot, rarpboot
881 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
882 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
883 CONFIG_CMD_PCI * pciinfo
884 CONFIG_CMD_PCMCIA * PCMCIA support
885 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
887 CONFIG_CMD_PORTIO * Port I/O
888 CONFIG_CMD_READ * Read raw data from partition
889 CONFIG_CMD_REGINFO * Register dump
890 CONFIG_CMD_RUN run command in env variable
891 CONFIG_CMD_SANDBOX * sb command to access sandbox features
892 CONFIG_CMD_SAVES * save S record dump
893 CONFIG_CMD_SCSI * SCSI Support
894 CONFIG_CMD_SDRAM * print SDRAM configuration information
895 (requires CONFIG_CMD_I2C)
896 CONFIG_CMD_SETGETDCR Support for DCR Register access
898 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
899 CONFIG_CMD_SHA1SUM print sha1 memory digest
900 (requires CONFIG_CMD_MEMORY)
901 CONFIG_CMD_SOURCE "source" command Support
902 CONFIG_CMD_SPI * SPI serial bus support
903 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
904 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
905 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
906 CONFIG_CMD_TIMER * access to the system tick timer
907 CONFIG_CMD_USB * USB support
908 CONFIG_CMD_CDP * Cisco Discover Protocol support
909 CONFIG_CMD_MFSL * Microblaze FSL support
912 EXAMPLE: If you want all functions except of network
913 support you can write:
915 #include "config_cmd_all.h"
916 #undef CONFIG_CMD_NET
919 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
921 Note: Don't enable the "icache" and "dcache" commands
922 (configuration option CONFIG_CMD_CACHE) unless you know
923 what you (and your U-Boot users) are doing. Data
924 cache cannot be enabled on systems like the 8xx or
925 8260 (where accesses to the IMMR region must be
926 uncached), and it cannot be disabled on all other
927 systems where we (mis-) use the data cache to hold an
928 initial stack and some data.
931 XXX - this list needs to get updated!
933 - Regular expression support:
935 If this variable is defined, U-Boot is linked against
936 the SLRE (Super Light Regular Expression) library,
937 which adds regex support to some commands, as for
938 example "env grep" and "setexpr".
942 If this variable is defined, U-Boot will use a device tree
943 to configure its devices, instead of relying on statically
944 compiled #defines in the board file. This option is
945 experimental and only available on a few boards. The device
946 tree is available in the global data as gd->fdt_blob.
948 U-Boot needs to get its device tree from somewhere. This can
949 be done using one of the two options below:
952 If this variable is defined, U-Boot will embed a device tree
953 binary in its image. This device tree file should be in the
954 board directory and called <soc>-<board>.dts. The binary file
955 is then picked up in board_init_f() and made available through
956 the global data structure as gd->blob.
959 If this variable is defined, U-Boot will build a device tree
960 binary. It will be called u-boot.dtb. Architecture-specific
961 code will locate it at run-time. Generally this works by:
963 cat u-boot.bin u-boot.dtb >image.bin
965 and in fact, U-Boot does this for you, creating a file called
966 u-boot-dtb.bin which is useful in the common case. You can
967 still use the individual files if you need something more
972 If this variable is defined, it enables watchdog
973 support for the SoC. There must be support in the SoC
974 specific code for a watchdog. For the 8xx and 8260
975 CPUs, the SIU Watchdog feature is enabled in the SYPCR
976 register. When supported for a specific SoC is
977 available, then no further board specific code should
981 When using a watchdog circuitry external to the used
982 SoC, then define this variable and provide board
983 specific code for the "hw_watchdog_reset" function.
986 CONFIG_VERSION_VARIABLE
987 If this variable is defined, an environment variable
988 named "ver" is created by U-Boot showing the U-Boot
989 version as printed by the "version" command.
990 Any change to this variable will be reverted at the
995 When CONFIG_CMD_DATE is selected, the type of the RTC
996 has to be selected, too. Define exactly one of the
999 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1000 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1001 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1002 CONFIG_RTC_MC146818 - use MC146818 RTC
1003 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1004 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1005 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1006 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1007 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1008 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1009 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1010 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1013 Note that if the RTC uses I2C, then the I2C interface
1014 must also be configured. See I2C Support, below.
1017 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1018 CONFIG_PCA953X_INFO - enable pca953x info command
1020 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1021 chip-ngpio pairs that tell the PCA953X driver the number of
1022 pins supported by a particular chip.
1024 Note that if the GPIO device uses I2C, then the I2C interface
1025 must also be configured. See I2C Support, below.
1027 - Timestamp Support:
1029 When CONFIG_TIMESTAMP is selected, the timestamp
1030 (date and time) of an image is printed by image
1031 commands like bootm or iminfo. This option is
1032 automatically enabled when you select CONFIG_CMD_DATE .
1034 - Partition Labels (disklabels) Supported:
1035 Zero or more of the following:
1036 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1037 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1038 Intel architecture, USB sticks, etc.
1039 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1040 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1041 bootloader. Note 2TB partition limit; see
1043 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1045 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1046 CONFIG_CMD_SCSI) you must configure support for at
1047 least one non-MTD partition type as well.
1050 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1051 board configurations files but used nowhere!
1053 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1054 be performed by calling the function
1055 ide_set_reset(int reset)
1056 which has to be defined in a board specific file
1061 Set this to enable ATAPI support.
1066 Set this to enable support for disks larger than 137GB
1067 Also look at CONFIG_SYS_64BIT_LBA.
1068 Whithout these , LBA48 support uses 32bit variables and will 'only'
1069 support disks up to 2.1TB.
1071 CONFIG_SYS_64BIT_LBA:
1072 When enabled, makes the IDE subsystem use 64bit sector addresses.
1076 At the moment only there is only support for the
1077 SYM53C8XX SCSI controller; define
1078 CONFIG_SCSI_SYM53C8XX to enable it.
1080 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1081 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1082 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1083 maximum numbers of LUNs, SCSI ID's and target
1085 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1087 The environment variable 'scsidevs' is set to the number of
1088 SCSI devices found during the last scan.
1090 - NETWORK Support (PCI):
1092 Support for Intel 8254x/8257x gigabit chips.
1095 Utility code for direct access to the SPI bus on Intel 8257x.
1096 This does not do anything useful unless you set at least one
1097 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1099 CONFIG_E1000_SPI_GENERIC
1100 Allow generic access to the SPI bus on the Intel 8257x, for
1101 example with the "sspi" command.
1104 Management command for E1000 devices. When used on devices
1105 with SPI support you can reprogram the EEPROM from U-Boot.
1107 CONFIG_E1000_FALLBACK_MAC
1108 default MAC for empty EEPROM after production.
1111 Support for Intel 82557/82559/82559ER chips.
1112 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1113 write routine for first time initialisation.
1116 Support for Digital 2114x chips.
1117 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1118 modem chip initialisation (KS8761/QS6611).
1121 Support for National dp83815 chips.
1124 Support for National dp8382[01] gigabit chips.
1126 - NETWORK Support (other):
1128 CONFIG_DRIVER_AT91EMAC
1129 Support for AT91RM9200 EMAC.
1132 Define this to use reduced MII inteface
1134 CONFIG_DRIVER_AT91EMAC_QUIET
1135 If this defined, the driver is quiet.
1136 The driver doen't show link status messages.
1138 CONFIG_CALXEDA_XGMAC
1139 Support for the Calxeda XGMAC device
1142 Support for SMSC's LAN91C96 chips.
1144 CONFIG_LAN91C96_BASE
1145 Define this to hold the physical address
1146 of the LAN91C96's I/O space
1148 CONFIG_LAN91C96_USE_32_BIT
1149 Define this to enable 32 bit addressing
1152 Support for SMSC's LAN91C111 chip
1154 CONFIG_SMC91111_BASE
1155 Define this to hold the physical address
1156 of the device (I/O space)
1158 CONFIG_SMC_USE_32_BIT
1159 Define this if data bus is 32 bits
1161 CONFIG_SMC_USE_IOFUNCS
1162 Define this to use i/o functions instead of macros
1163 (some hardware wont work with macros)
1165 CONFIG_DRIVER_TI_EMAC
1166 Support for davinci emac
1168 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1169 Define this if you have more then 3 PHYs.
1172 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1174 CONFIG_FTGMAC100_EGIGA
1175 Define this to use GE link update with gigabit PHY.
1176 Define this if FTGMAC100 is connected to gigabit PHY.
1177 If your system has 10/100 PHY only, it might not occur
1178 wrong behavior. Because PHY usually return timeout or
1179 useless data when polling gigabit status and gigabit
1180 control registers. This behavior won't affect the
1181 correctnessof 10/100 link speed update.
1184 Support for SMSC's LAN911x and LAN921x chips
1187 Define this to hold the physical address
1188 of the device (I/O space)
1190 CONFIG_SMC911X_32_BIT
1191 Define this if data bus is 32 bits
1193 CONFIG_SMC911X_16_BIT
1194 Define this if data bus is 16 bits. If your processor
1195 automatically converts one 32 bit word to two 16 bit
1196 words you may also try CONFIG_SMC911X_32_BIT.
1199 Support for Renesas on-chip Ethernet controller
1201 CONFIG_SH_ETHER_USE_PORT
1202 Define the number of ports to be used
1204 CONFIG_SH_ETHER_PHY_ADDR
1205 Define the ETH PHY's address
1207 CONFIG_SH_ETHER_CACHE_WRITEBACK
1208 If this option is set, the driver enables cache flush.
1211 CONFIG_GENERIC_LPC_TPM
1212 Support for generic parallel port TPM devices. Only one device
1213 per system is supported at this time.
1215 CONFIG_TPM_TIS_BASE_ADDRESS
1216 Base address where the generic TPM device is mapped
1217 to. Contemporary x86 systems usually map it at
1221 At the moment only the UHCI host controller is
1222 supported (PIP405, MIP405, MPC5200); define
1223 CONFIG_USB_UHCI to enable it.
1224 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1225 and define CONFIG_USB_STORAGE to enable the USB
1228 Supported are USB Keyboards and USB Floppy drives
1230 MPC5200 USB requires additional defines:
1232 for 528 MHz Clock: 0x0001bbbb
1236 for differential drivers: 0x00001000
1237 for single ended drivers: 0x00005000
1238 for differential drivers on PSC3: 0x00000100
1239 for single ended drivers on PSC3: 0x00004100
1240 CONFIG_SYS_USB_EVENT_POLL
1241 May be defined to allow interrupt polling
1242 instead of using asynchronous interrupts
1244 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1245 txfilltuning field in the EHCI controller on reset.
1248 Define the below if you wish to use the USB console.
1249 Once firmware is rebuilt from a serial console issue the
1250 command "setenv stdin usbtty; setenv stdout usbtty" and
1251 attach your USB cable. The Unix command "dmesg" should print
1252 it has found a new device. The environment variable usbtty
1253 can be set to gserial or cdc_acm to enable your device to
1254 appear to a USB host as a Linux gserial device or a
1255 Common Device Class Abstract Control Model serial device.
1256 If you select usbtty = gserial you should be able to enumerate
1258 # modprobe usbserial vendor=0xVendorID product=0xProductID
1259 else if using cdc_acm, simply setting the environment
1260 variable usbtty to be cdc_acm should suffice. The following
1261 might be defined in YourBoardName.h
1264 Define this to build a UDC device
1267 Define this to have a tty type of device available to
1268 talk to the UDC device
1271 Define this to enable the high speed support for usb
1272 device and usbtty. If this feature is enabled, a routine
1273 int is_usbd_high_speed(void)
1274 also needs to be defined by the driver to dynamically poll
1275 whether the enumeration has succeded at high speed or full
1278 CONFIG_SYS_CONSOLE_IS_IN_ENV
1279 Define this if you want stdin, stdout &/or stderr to
1283 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1284 Derive USB clock from external clock "blah"
1285 - CONFIG_SYS_USB_EXTC_CLK 0x02
1287 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1288 Derive USB clock from brgclk
1289 - CONFIG_SYS_USB_BRG_CLK 0x04
1291 If you have a USB-IF assigned VendorID then you may wish to
1292 define your own vendor specific values either in BoardName.h
1293 or directly in usbd_vendor_info.h. If you don't define
1294 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1295 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1296 should pretend to be a Linux device to it's target host.
1298 CONFIG_USBD_MANUFACTURER
1299 Define this string as the name of your company for
1300 - CONFIG_USBD_MANUFACTURER "my company"
1302 CONFIG_USBD_PRODUCT_NAME
1303 Define this string as the name of your product
1304 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1306 CONFIG_USBD_VENDORID
1307 Define this as your assigned Vendor ID from the USB
1308 Implementors Forum. This *must* be a genuine Vendor ID
1309 to avoid polluting the USB namespace.
1310 - CONFIG_USBD_VENDORID 0xFFFF
1312 CONFIG_USBD_PRODUCTID
1313 Define this as the unique Product ID
1315 - CONFIG_USBD_PRODUCTID 0xFFFF
1317 - ULPI Layer Support:
1318 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1319 the generic ULPI layer. The generic layer accesses the ULPI PHY
1320 via the platform viewport, so you need both the genric layer and
1321 the viewport enabled. Currently only Chipidea/ARC based
1322 viewport is supported.
1323 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1324 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1325 If your ULPI phy needs a different reference clock than the
1326 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1327 the appropriate value in Hz.
1330 The MMC controller on the Intel PXA is supported. To
1331 enable this define CONFIG_MMC. The MMC can be
1332 accessed from the boot prompt by mapping the device
1333 to physical memory similar to flash. Command line is
1334 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1335 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1338 Support for Renesas on-chip MMCIF controller
1340 CONFIG_SH_MMCIF_ADDR
1341 Define the base address of MMCIF registers
1344 Define the clock frequency for MMCIF
1346 - USB Device Firmware Update (DFU) class support:
1348 This enables the USB portion of the DFU USB class
1351 This enables the command "dfu" which is used to have
1352 U-Boot create a DFU class device via USB. This command
1353 requires that the "dfu_alt_info" environment variable be
1354 set and define the alt settings to expose to the host.
1357 This enables support for exposing (e)MMC devices via DFU.
1360 This enables support for exposing NAND devices via DFU.
1362 CONFIG_SYS_DFU_MAX_FILE_SIZE
1363 When updating files rather than the raw storage device,
1364 we use a static buffer to copy the file into and then write
1365 the buffer once we've been given the whole file. Define
1366 this to the maximum filesize (in bytes) for the buffer.
1367 Default is 4 MiB if undefined.
1369 - Journaling Flash filesystem support:
1370 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1371 CONFIG_JFFS2_NAND_DEV
1372 Define these for a default partition on a NAND device
1374 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1375 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1376 Define these for a default partition on a NOR device
1378 CONFIG_SYS_JFFS_CUSTOM_PART
1379 Define this to create an own partition. You have to provide a
1380 function struct part_info* jffs2_part_info(int part_num)
1382 If you define only one JFFS2 partition you may also want to
1383 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1384 to disable the command chpart. This is the default when you
1385 have not defined a custom partition
1387 - FAT(File Allocation Table) filesystem write function support:
1390 Define this to enable support for saving memory data as a
1391 file in FAT formatted partition.
1393 This will also enable the command "fatwrite" enabling the
1394 user to write files to FAT.
1396 CBFS (Coreboot Filesystem) support
1399 Define this to enable support for reading from a Coreboot
1400 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1406 Define this to enable standard (PC-Style) keyboard
1410 Standard PC keyboard driver with US (is default) and
1411 GERMAN key layout (switch via environment 'keymap=de') support.
1412 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1413 for cfb_console. Supports cursor blinking.
1418 Define this to enable video support (for output to
1421 CONFIG_VIDEO_CT69000
1423 Enable Chips & Technologies 69000 Video chip
1425 CONFIG_VIDEO_SMI_LYNXEM
1426 Enable Silicon Motion SMI 712/710/810 Video chip. The
1427 video output is selected via environment 'videoout'
1428 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1431 For the CT69000 and SMI_LYNXEM drivers, videomode is
1432 selected via environment 'videomode'. Two different ways
1434 - "videomode=num" 'num' is a standard LiLo mode numbers.
1435 Following standard modes are supported (* is default):
1437 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1438 -------------+---------------------------------------------
1439 8 bits | 0x301* 0x303 0x305 0x161 0x307
1440 15 bits | 0x310 0x313 0x316 0x162 0x319
1441 16 bits | 0x311 0x314 0x317 0x163 0x31A
1442 24 bits | 0x312 0x315 0x318 ? 0x31B
1443 -------------+---------------------------------------------
1444 (i.e. setenv videomode 317; saveenv; reset;)
1446 - "videomode=bootargs" all the video parameters are parsed
1447 from the bootargs. (See drivers/video/videomodes.c)
1450 CONFIG_VIDEO_SED13806
1451 Enable Epson SED13806 driver. This driver supports 8bpp
1452 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1453 or CONFIG_VIDEO_SED13806_16BPP
1456 Enable the Freescale DIU video driver. Reference boards for
1457 SOCs that have a DIU should define this macro to enable DIU
1458 support, and should also define these other macros:
1464 CONFIG_VIDEO_SW_CURSOR
1465 CONFIG_VGA_AS_SINGLE_DEVICE
1467 CONFIG_VIDEO_BMP_LOGO
1469 The DIU driver will look for the 'video-mode' environment
1470 variable, and if defined, enable the DIU as a console during
1471 boot. See the documentation file README.video for a
1472 description of this variable.
1476 Enable the VGA video / BIOS for x86. The alternative if you
1477 are using coreboot is to use the coreboot frame buffer
1484 Define this to enable a custom keyboard support.
1485 This simply calls drv_keyboard_init() which must be
1486 defined in your board-specific files.
1487 The only board using this so far is RBC823.
1489 - LCD Support: CONFIG_LCD
1491 Define this to enable LCD support (for output to LCD
1492 display); also select one of the supported displays
1493 by defining one of these:
1497 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1499 CONFIG_NEC_NL6448AC33:
1501 NEC NL6448AC33-18. Active, color, single scan.
1503 CONFIG_NEC_NL6448BC20
1505 NEC NL6448BC20-08. 6.5", 640x480.
1506 Active, color, single scan.
1508 CONFIG_NEC_NL6448BC33_54
1510 NEC NL6448BC33-54. 10.4", 640x480.
1511 Active, color, single scan.
1515 Sharp 320x240. Active, color, single scan.
1516 It isn't 16x9, and I am not sure what it is.
1518 CONFIG_SHARP_LQ64D341
1520 Sharp LQ64D341 display, 640x480.
1521 Active, color, single scan.
1525 HLD1045 display, 640x480.
1526 Active, color, single scan.
1530 Optrex CBL50840-2 NF-FW 99 22 M5
1532 Hitachi LMG6912RPFC-00T
1536 320x240. Black & white.
1538 Normally display is black on white background; define
1539 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1541 CONFIG_LCD_ALIGNMENT
1543 Normally the LCD is page-aligned (tyically 4KB). If this is
1544 defined then the LCD will be aligned to this value instead.
1545 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1546 here, since it is cheaper to change data cache settings on
1547 a per-section basis.
1549 CONFIG_CONSOLE_SCROLL_LINES
1551 When the console need to be scrolled, this is the number of
1552 lines to scroll by. It defaults to 1. Increasing this makes
1553 the console jump but can help speed up operation when scrolling
1558 Support drawing of RLE8-compressed bitmaps on the LCD.
1562 Enables an 'i2c edid' command which can read EDID
1563 information over I2C from an attached LCD display.
1565 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1567 If this option is set, the environment is checked for
1568 a variable "splashimage". If found, the usual display
1569 of logo, copyright and system information on the LCD
1570 is suppressed and the BMP image at the address
1571 specified in "splashimage" is loaded instead. The
1572 console is redirected to the "nulldev", too. This
1573 allows for a "silent" boot where a splash screen is
1574 loaded very quickly after power-on.
1576 CONFIG_SPLASHIMAGE_GUARD
1578 If this option is set, then U-Boot will prevent the environment
1579 variable "splashimage" from being set to a problematic address
1580 (see README.displaying-bmps and README.arm-unaligned-accesses).
1581 This option is useful for targets where, due to alignment
1582 restrictions, an improperly aligned BMP image will cause a data
1583 abort. If you think you will not have problems with unaligned
1584 accesses (for example because your toolchain prevents them)
1585 there is no need to set this option.
1587 CONFIG_SPLASH_SCREEN_ALIGN
1589 If this option is set the splash image can be freely positioned
1590 on the screen. Environment variable "splashpos" specifies the
1591 position as "x,y". If a positive number is given it is used as
1592 number of pixel from left/top. If a negative number is given it
1593 is used as number of pixel from right/bottom. You can also
1594 specify 'm' for centering the image.
1597 setenv splashpos m,m
1598 => image at center of screen
1600 setenv splashpos 30,20
1601 => image at x = 30 and y = 20
1603 setenv splashpos -10,m
1604 => vertically centered image
1605 at x = dspWidth - bmpWidth - 9
1607 CONFIG_SPLASH_SCREEN_PREPARE
1609 If this option is set then the board_splash_screen_prepare()
1610 function, which must be defined in your code, is called as part
1611 of the splash screen display sequence. It gives the board an
1612 opportunity to prepare the splash image data before it is
1613 processed and sent to the frame buffer by U-Boot.
1615 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1617 If this option is set, additionally to standard BMP
1618 images, gzipped BMP images can be displayed via the
1619 splashscreen support or the bmp command.
1621 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1623 If this option is set, 8-bit RLE compressed BMP images
1624 can be displayed via the splashscreen support or the
1627 - Do compresssing for memory range:
1630 If this option is set, it would use zlib deflate method
1631 to compress the specified memory at its best effort.
1633 - Compression support:
1636 If this option is set, support for bzip2 compressed
1637 images is included. If not, only uncompressed and gzip
1638 compressed images are supported.
1640 NOTE: the bzip2 algorithm requires a lot of RAM, so
1641 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1646 If this option is set, support for lzma compressed
1649 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1650 requires an amount of dynamic memory that is given by the
1653 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1655 Where lc and lp stand for, respectively, Literal context bits
1656 and Literal pos bits.
1658 This value is upper-bounded by 14MB in the worst case. Anyway,
1659 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1660 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1661 a very small buffer.
1663 Use the lzmainfo tool to determinate the lc and lp values and
1664 then calculate the amount of needed dynamic memory (ensuring
1665 the appropriate CONFIG_SYS_MALLOC_LEN value).
1670 The address of PHY on MII bus.
1672 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1674 The clock frequency of the MII bus
1678 If this option is set, support for speed/duplex
1679 detection of gigabit PHY is included.
1681 CONFIG_PHY_RESET_DELAY
1683 Some PHY like Intel LXT971A need extra delay after
1684 reset before any MII register access is possible.
1685 For such PHY, set this option to the usec delay
1686 required. (minimum 300usec for LXT971A)
1688 CONFIG_PHY_CMD_DELAY (ppc4xx)
1690 Some PHY like Intel LXT971A need extra delay after
1691 command issued before MII status register can be read
1701 Define a default value for Ethernet address to use
1702 for the respective Ethernet interface, in case this
1703 is not determined automatically.
1708 Define a default value for the IP address to use for
1709 the default Ethernet interface, in case this is not
1710 determined through e.g. bootp.
1711 (Environment variable "ipaddr")
1713 - Server IP address:
1716 Defines a default value for the IP address of a TFTP
1717 server to contact when using the "tftboot" command.
1718 (Environment variable "serverip")
1720 CONFIG_KEEP_SERVERADDR
1722 Keeps the server's MAC address, in the env 'serveraddr'
1723 for passing to bootargs (like Linux's netconsole option)
1725 - Gateway IP address:
1728 Defines a default value for the IP address of the
1729 default router where packets to other networks are
1731 (Environment variable "gatewayip")
1736 Defines a default value for the subnet mask (or
1737 routing prefix) which is used to determine if an IP
1738 address belongs to the local subnet or needs to be
1739 forwarded through a router.
1740 (Environment variable "netmask")
1742 - Multicast TFTP Mode:
1745 Defines whether you want to support multicast TFTP as per
1746 rfc-2090; for example to work with atftp. Lets lots of targets
1747 tftp down the same boot image concurrently. Note: the Ethernet
1748 driver in use must provide a function: mcast() to join/leave a
1751 - BOOTP Recovery Mode:
1752 CONFIG_BOOTP_RANDOM_DELAY
1754 If you have many targets in a network that try to
1755 boot using BOOTP, you may want to avoid that all
1756 systems send out BOOTP requests at precisely the same
1757 moment (which would happen for instance at recovery
1758 from a power failure, when all systems will try to
1759 boot, thus flooding the BOOTP server. Defining
1760 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1761 inserted before sending out BOOTP requests. The
1762 following delays are inserted then:
1764 1st BOOTP request: delay 0 ... 1 sec
1765 2nd BOOTP request: delay 0 ... 2 sec
1766 3rd BOOTP request: delay 0 ... 4 sec
1768 BOOTP requests: delay 0 ... 8 sec
1770 - DHCP Advanced Options:
1771 You can fine tune the DHCP functionality by defining
1772 CONFIG_BOOTP_* symbols:
1774 CONFIG_BOOTP_SUBNETMASK
1775 CONFIG_BOOTP_GATEWAY
1776 CONFIG_BOOTP_HOSTNAME
1777 CONFIG_BOOTP_NISDOMAIN
1778 CONFIG_BOOTP_BOOTPATH
1779 CONFIG_BOOTP_BOOTFILESIZE
1782 CONFIG_BOOTP_SEND_HOSTNAME
1783 CONFIG_BOOTP_NTPSERVER
1784 CONFIG_BOOTP_TIMEOFFSET
1785 CONFIG_BOOTP_VENDOREX
1786 CONFIG_BOOTP_MAY_FAIL
1788 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1789 environment variable, not the BOOTP server.
1791 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1792 after the configured retry count, the call will fail
1793 instead of starting over. This can be used to fail over
1794 to Link-local IP address configuration if the DHCP server
1797 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1798 serverip from a DHCP server, it is possible that more
1799 than one DNS serverip is offered to the client.
1800 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1801 serverip will be stored in the additional environment
1802 variable "dnsip2". The first DNS serverip is always
1803 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1806 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1807 to do a dynamic update of a DNS server. To do this, they
1808 need the hostname of the DHCP requester.
1809 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1810 of the "hostname" environment variable is passed as
1811 option 12 to the DHCP server.
1813 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1815 A 32bit value in microseconds for a delay between
1816 receiving a "DHCP Offer" and sending the "DHCP Request".
1817 This fixes a problem with certain DHCP servers that don't
1818 respond 100% of the time to a "DHCP request". E.g. On an
1819 AT91RM9200 processor running at 180MHz, this delay needed
1820 to be *at least* 15,000 usec before a Windows Server 2003
1821 DHCP server would reply 100% of the time. I recommend at
1822 least 50,000 usec to be safe. The alternative is to hope
1823 that one of the retries will be successful but note that
1824 the DHCP timeout and retry process takes a longer than
1827 - Link-local IP address negotiation:
1828 Negotiate with other link-local clients on the local network
1829 for an address that doesn't require explicit configuration.
1830 This is especially useful if a DHCP server cannot be guaranteed
1831 to exist in all environments that the device must operate.
1833 See doc/README.link-local for more information.
1836 CONFIG_CDP_DEVICE_ID
1838 The device id used in CDP trigger frames.
1840 CONFIG_CDP_DEVICE_ID_PREFIX
1842 A two character string which is prefixed to the MAC address
1847 A printf format string which contains the ascii name of
1848 the port. Normally is set to "eth%d" which sets
1849 eth0 for the first Ethernet, eth1 for the second etc.
1851 CONFIG_CDP_CAPABILITIES
1853 A 32bit integer which indicates the device capabilities;
1854 0x00000010 for a normal host which does not forwards.
1858 An ascii string containing the version of the software.
1862 An ascii string containing the name of the platform.
1866 A 32bit integer sent on the trigger.
1868 CONFIG_CDP_POWER_CONSUMPTION
1870 A 16bit integer containing the power consumption of the
1871 device in .1 of milliwatts.
1873 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1875 A byte containing the id of the VLAN.
1877 - Status LED: CONFIG_STATUS_LED
1879 Several configurations allow to display the current
1880 status using a LED. For instance, the LED will blink
1881 fast while running U-Boot code, stop blinking as
1882 soon as a reply to a BOOTP request was received, and
1883 start blinking slow once the Linux kernel is running
1884 (supported by a status LED driver in the Linux
1885 kernel). Defining CONFIG_STATUS_LED enables this
1888 - CAN Support: CONFIG_CAN_DRIVER
1890 Defining CONFIG_CAN_DRIVER enables CAN driver support
1891 on those systems that support this (optional)
1892 feature, like the TQM8xxL modules.
1894 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1896 These enable I2C serial bus commands. Defining either of
1897 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1898 include the appropriate I2C driver for the selected CPU.
1900 This will allow you to use i2c commands at the u-boot
1901 command line (as long as you set CONFIG_CMD_I2C in
1902 CONFIG_COMMANDS) and communicate with i2c based realtime
1903 clock chips. See common/cmd_i2c.c for a description of the
1904 command line interface.
1906 CONFIG_HARD_I2C selects a hardware I2C controller.
1908 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1909 bit-banging) driver instead of CPM or similar hardware
1912 There are several other quantities that must also be
1913 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1915 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1916 to be the frequency (in Hz) at which you wish your i2c bus
1917 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1918 the CPU's i2c node address).
1920 Now, the u-boot i2c code for the mpc8xx
1921 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1922 and so its address should therefore be cleared to 0 (See,
1923 eg, MPC823e User's Manual p.16-473). So, set
1924 CONFIG_SYS_I2C_SLAVE to 0.
1926 CONFIG_SYS_I2C_INIT_MPC5XXX
1928 When a board is reset during an i2c bus transfer
1929 chips might think that the current transfer is still
1930 in progress. Reset the slave devices by sending start
1931 commands until the slave device responds.
1933 That's all that's required for CONFIG_HARD_I2C.
1935 If you use the software i2c interface (CONFIG_SOFT_I2C)
1936 then the following macros need to be defined (examples are
1937 from include/configs/lwmon.h):
1941 (Optional). Any commands necessary to enable the I2C
1942 controller or configure ports.
1944 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1948 (Only for MPC8260 CPU). The I/O port to use (the code
1949 assumes both bits are on the same port). Valid values
1950 are 0..3 for ports A..D.
1954 The code necessary to make the I2C data line active
1955 (driven). If the data line is open collector, this
1958 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1962 The code necessary to make the I2C data line tri-stated
1963 (inactive). If the data line is open collector, this
1966 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1970 Code that returns true if the I2C data line is high,
1973 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1977 If <bit> is true, sets the I2C data line high. If it
1978 is false, it clears it (low).
1980 eg: #define I2C_SDA(bit) \
1981 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1982 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1986 If <bit> is true, sets the I2C clock line high. If it
1987 is false, it clears it (low).
1989 eg: #define I2C_SCL(bit) \
1990 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1991 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1995 This delay is invoked four times per clock cycle so this
1996 controls the rate of data transfer. The data rate thus
1997 is 1 / (I2C_DELAY * 4). Often defined to be something
2000 #define I2C_DELAY udelay(2)
2002 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2004 If your arch supports the generic GPIO framework (asm/gpio.h),
2005 then you may alternatively define the two GPIOs that are to be
2006 used as SCL / SDA. Any of the previous I2C_xxx macros will
2007 have GPIO-based defaults assigned to them as appropriate.
2009 You should define these to the GPIO value as given directly to
2010 the generic GPIO functions.
2012 CONFIG_SYS_I2C_INIT_BOARD
2014 When a board is reset during an i2c bus transfer
2015 chips might think that the current transfer is still
2016 in progress. On some boards it is possible to access
2017 the i2c SCLK line directly, either by using the
2018 processor pin as a GPIO or by having a second pin
2019 connected to the bus. If this option is defined a
2020 custom i2c_init_board() routine in boards/xxx/board.c
2021 is run early in the boot sequence.
2023 CONFIG_SYS_I2C_BOARD_LATE_INIT
2025 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2026 defined a custom i2c_board_late_init() routine in
2027 boards/xxx/board.c is run AFTER the operations in i2c_init()
2028 is completed. This callpoint can be used to unreset i2c bus
2029 using CPU i2c controller register accesses for CPUs whose i2c
2030 controller provide such a method. It is called at the end of
2031 i2c_init() to allow i2c_init operations to setup the i2c bus
2032 controller on the CPU (e.g. setting bus speed & slave address).
2034 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2036 This option enables configuration of bi_iic_fast[] flags
2037 in u-boot bd_info structure based on u-boot environment
2038 variable "i2cfast". (see also i2cfast)
2040 CONFIG_I2C_MULTI_BUS
2042 This option allows the use of multiple I2C buses, each of which
2043 must have a controller. At any point in time, only one bus is
2044 active. To switch to a different bus, use the 'i2c dev' command.
2045 Note that bus numbering is zero-based.
2047 CONFIG_SYS_I2C_NOPROBES
2049 This option specifies a list of I2C devices that will be skipped
2050 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2051 is set, specify a list of bus-device pairs. Otherwise, specify
2052 a 1D array of device addresses
2055 #undef CONFIG_I2C_MULTI_BUS
2056 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2058 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2060 #define CONFIG_I2C_MULTI_BUS
2061 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2063 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2065 CONFIG_SYS_SPD_BUS_NUM
2067 If defined, then this indicates the I2C bus number for DDR SPD.
2068 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2070 CONFIG_SYS_RTC_BUS_NUM
2072 If defined, then this indicates the I2C bus number for the RTC.
2073 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2075 CONFIG_SYS_DTT_BUS_NUM
2077 If defined, then this indicates the I2C bus number for the DTT.
2078 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2080 CONFIG_SYS_I2C_DTT_ADDR:
2082 If defined, specifies the I2C address of the DTT device.
2083 If not defined, then U-Boot uses predefined value for
2084 specified DTT device.
2088 Define this option if you want to use Freescale's I2C driver in
2089 drivers/i2c/fsl_i2c.c.
2093 Define this option if you have I2C devices reached over 1 .. n
2094 I2C Muxes like the pca9544a. This option addes a new I2C
2095 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2096 new I2C Bus to the existing I2C Busses. If you select the
2097 new Bus with "i2c dev", u-bbot sends first the commandos for
2098 the muxes to activate this new "bus".
2100 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2104 Adding a new I2C Bus reached over 2 pca9544a muxes
2105 The First mux with address 70 and channel 6
2106 The Second mux with address 71 and channel 4
2108 => i2c bus pca9544a:70:6:pca9544a:71:4
2110 Use the "i2c bus" command without parameter, to get a list
2111 of I2C Busses with muxes:
2114 Busses reached over muxes:
2116 reached over Mux(es):
2119 reached over Mux(es):
2124 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2125 u-boot first sends the command to the mux@70 to enable
2126 channel 6, and then the command to the mux@71 to enable
2129 After that, you can use the "normal" i2c commands as
2130 usual to communicate with your I2C devices behind
2133 This option is actually implemented for the bitbanging
2134 algorithm in common/soft_i2c.c and for the Hardware I2C
2135 Bus on the MPC8260. But it should be not so difficult
2136 to add this option to other architectures.
2138 CONFIG_SOFT_I2C_READ_REPEATED_START
2140 defining this will force the i2c_read() function in
2141 the soft_i2c driver to perform an I2C repeated start
2142 between writing the address pointer and reading the
2143 data. If this define is omitted the default behaviour
2144 of doing a stop-start sequence will be used. Most I2C
2145 devices can use either method, but some require one or
2148 - SPI Support: CONFIG_SPI
2150 Enables SPI driver (so far only tested with
2151 SPI EEPROM, also an instance works with Crystal A/D and
2152 D/As on the SACSng board)
2156 Enables the driver for SPI controller on SuperH. Currently
2157 only SH7757 is supported.
2161 Enables extended (16-bit) SPI EEPROM addressing.
2162 (symmetrical to CONFIG_I2C_X)
2166 Enables a software (bit-bang) SPI driver rather than
2167 using hardware support. This is a general purpose
2168 driver that only requires three general I/O port pins
2169 (two outputs, one input) to function. If this is
2170 defined, the board configuration must define several
2171 SPI configuration items (port pins to use, etc). For
2172 an example, see include/configs/sacsng.h.
2176 Enables a hardware SPI driver for general-purpose reads
2177 and writes. As with CONFIG_SOFT_SPI, the board configuration
2178 must define a list of chip-select function pointers.
2179 Currently supported on some MPC8xxx processors. For an
2180 example, see include/configs/mpc8349emds.h.
2184 Enables the driver for the SPI controllers on i.MX and MXC
2185 SoCs. Currently i.MX31/35/51 are supported.
2187 - FPGA Support: CONFIG_FPGA
2189 Enables FPGA subsystem.
2191 CONFIG_FPGA_<vendor>
2193 Enables support for specific chip vendors.
2196 CONFIG_FPGA_<family>
2198 Enables support for FPGA family.
2199 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2203 Specify the number of FPGA devices to support.
2205 CONFIG_SYS_FPGA_PROG_FEEDBACK
2207 Enable printing of hash marks during FPGA configuration.
2209 CONFIG_SYS_FPGA_CHECK_BUSY
2211 Enable checks on FPGA configuration interface busy
2212 status by the configuration function. This option
2213 will require a board or device specific function to
2218 If defined, a function that provides delays in the FPGA
2219 configuration driver.
2221 CONFIG_SYS_FPGA_CHECK_CTRLC
2222 Allow Control-C to interrupt FPGA configuration
2224 CONFIG_SYS_FPGA_CHECK_ERROR
2226 Check for configuration errors during FPGA bitfile
2227 loading. For example, abort during Virtex II
2228 configuration if the INIT_B line goes low (which
2229 indicated a CRC error).
2231 CONFIG_SYS_FPGA_WAIT_INIT
2233 Maximum time to wait for the INIT_B line to deassert
2234 after PROB_B has been deasserted during a Virtex II
2235 FPGA configuration sequence. The default time is 500
2238 CONFIG_SYS_FPGA_WAIT_BUSY
2240 Maximum time to wait for BUSY to deassert during
2241 Virtex II FPGA configuration. The default is 5 ms.
2243 CONFIG_SYS_FPGA_WAIT_CONFIG
2245 Time to wait after FPGA configuration. The default is
2248 - Configuration Management:
2251 If defined, this string will be added to the U-Boot
2252 version information (U_BOOT_VERSION)
2254 - Vendor Parameter Protection:
2256 U-Boot considers the values of the environment
2257 variables "serial#" (Board Serial Number) and
2258 "ethaddr" (Ethernet Address) to be parameters that
2259 are set once by the board vendor / manufacturer, and
2260 protects these variables from casual modification by
2261 the user. Once set, these variables are read-only,
2262 and write or delete attempts are rejected. You can
2263 change this behaviour:
2265 If CONFIG_ENV_OVERWRITE is #defined in your config
2266 file, the write protection for vendor parameters is
2267 completely disabled. Anybody can change or delete
2270 Alternatively, if you #define _both_ CONFIG_ETHADDR
2271 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2272 Ethernet address is installed in the environment,
2273 which can be changed exactly ONCE by the user. [The
2274 serial# is unaffected by this, i. e. it remains
2277 The same can be accomplished in a more flexible way
2278 for any variable by configuring the type of access
2279 to allow for those variables in the ".flags" variable
2280 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2285 Define this variable to enable the reservation of
2286 "protected RAM", i. e. RAM which is not overwritten
2287 by U-Boot. Define CONFIG_PRAM to hold the number of
2288 kB you want to reserve for pRAM. You can overwrite
2289 this default value by defining an environment
2290 variable "pram" to the number of kB you want to
2291 reserve. Note that the board info structure will
2292 still show the full amount of RAM. If pRAM is
2293 reserved, a new environment variable "mem" will
2294 automatically be defined to hold the amount of
2295 remaining RAM in a form that can be passed as boot
2296 argument to Linux, for instance like that:
2298 setenv bootargs ... mem=\${mem}
2301 This way you can tell Linux not to use this memory,
2302 either, which results in a memory region that will
2303 not be affected by reboots.
2305 *WARNING* If your board configuration uses automatic
2306 detection of the RAM size, you must make sure that
2307 this memory test is non-destructive. So far, the
2308 following board configurations are known to be
2311 IVMS8, IVML24, SPD8xx, TQM8xxL,
2312 HERMES, IP860, RPXlite, LWMON,
2315 - Access to physical memory region (> 4GB)
2316 Some basic support is provided for operations on memory not
2317 normally accessible to U-Boot - e.g. some architectures
2318 support access to more than 4GB of memory on 32-bit
2319 machines using physical address extension or similar.
2320 Define CONFIG_PHYSMEM to access this basic support, which
2321 currently only supports clearing the memory.
2326 Define this variable to stop the system in case of a
2327 fatal error, so that you have to reset it manually.
2328 This is probably NOT a good idea for an embedded
2329 system where you want the system to reboot
2330 automatically as fast as possible, but it may be
2331 useful during development since you can try to debug
2332 the conditions that lead to the situation.
2334 CONFIG_NET_RETRY_COUNT
2336 This variable defines the number of retries for
2337 network operations like ARP, RARP, TFTP, or BOOTP
2338 before giving up the operation. If not defined, a
2339 default value of 5 is used.
2343 Timeout waiting for an ARP reply in milliseconds.
2347 Timeout in milliseconds used in NFS protocol.
2348 If you encounter "ERROR: Cannot umount" in nfs command,
2349 try longer timeout such as
2350 #define CONFIG_NFS_TIMEOUT 10000UL
2352 - Command Interpreter:
2353 CONFIG_AUTO_COMPLETE
2355 Enable auto completion of commands using TAB.
2357 Note that this feature has NOT been implemented yet
2358 for the "hush" shell.
2361 CONFIG_SYS_HUSH_PARSER
2363 Define this variable to enable the "hush" shell (from
2364 Busybox) as command line interpreter, thus enabling
2365 powerful command line syntax like
2366 if...then...else...fi conditionals or `&&' and '||'
2367 constructs ("shell scripts").
2369 If undefined, you get the old, much simpler behaviour
2370 with a somewhat smaller memory footprint.
2373 CONFIG_SYS_PROMPT_HUSH_PS2
2375 This defines the secondary prompt string, which is
2376 printed when the command interpreter needs more input
2377 to complete a command. Usually "> ".
2381 In the current implementation, the local variables
2382 space and global environment variables space are
2383 separated. Local variables are those you define by
2384 simply typing `name=value'. To access a local
2385 variable later on, you have write `$name' or
2386 `${name}'; to execute the contents of a variable
2387 directly type `$name' at the command prompt.
2389 Global environment variables are those you use
2390 setenv/printenv to work with. To run a command stored
2391 in such a variable, you need to use the run command,
2392 and you must not use the '$' sign to access them.
2394 To store commands and special characters in a
2395 variable, please use double quotation marks
2396 surrounding the whole text of the variable, instead
2397 of the backslashes before semicolons and special
2400 - Commandline Editing and History:
2401 CONFIG_CMDLINE_EDITING
2403 Enable editing and History functions for interactive
2404 commandline input operations
2406 - Default Environment:
2407 CONFIG_EXTRA_ENV_SETTINGS
2409 Define this to contain any number of null terminated
2410 strings (variable = value pairs) that will be part of
2411 the default environment compiled into the boot image.
2413 For example, place something like this in your
2414 board's config file:
2416 #define CONFIG_EXTRA_ENV_SETTINGS \
2420 Warning: This method is based on knowledge about the
2421 internal format how the environment is stored by the
2422 U-Boot code. This is NOT an official, exported
2423 interface! Although it is unlikely that this format
2424 will change soon, there is no guarantee either.
2425 You better know what you are doing here.
2427 Note: overly (ab)use of the default environment is
2428 discouraged. Make sure to check other ways to preset
2429 the environment like the "source" command or the
2432 CONFIG_ENV_VARS_UBOOT_CONFIG
2434 Define this in order to add variables describing the
2435 U-Boot build configuration to the default environment.
2436 These will be named arch, cpu, board, vendor, and soc.
2438 Enabling this option will cause the following to be defined:
2446 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2448 Define this in order to add variables describing certain
2449 run-time determined information about the hardware to the
2450 environment. These will be named board_name, board_rev.
2452 CONFIG_DELAY_ENVIRONMENT
2454 Normally the environment is loaded when the board is
2455 intialised so that it is available to U-Boot. This inhibits
2456 that so that the environment is not available until
2457 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2458 this is instead controlled by the value of
2459 /config/load-environment.
2461 - DataFlash Support:
2462 CONFIG_HAS_DATAFLASH
2464 Defining this option enables DataFlash features and
2465 allows to read/write in Dataflash via the standard
2468 - Serial Flash support
2471 Defining this option enables SPI flash commands
2472 'sf probe/read/write/erase/update'.
2474 Usage requires an initial 'probe' to define the serial
2475 flash parameters, followed by read/write/erase/update
2478 The following defaults may be provided by the platform
2479 to handle the common case when only a single serial
2480 flash is present on the system.
2482 CONFIG_SF_DEFAULT_BUS Bus identifier
2483 CONFIG_SF_DEFAULT_CS Chip-select
2484 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2485 CONFIG_SF_DEFAULT_SPEED in Hz
2489 Define this option to include a destructive SPI flash
2492 - SystemACE Support:
2495 Adding this option adds support for Xilinx SystemACE
2496 chips attached via some sort of local bus. The address
2497 of the chip must also be defined in the
2498 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2500 #define CONFIG_SYSTEMACE
2501 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2503 When SystemACE support is added, the "ace" device type
2504 becomes available to the fat commands, i.e. fatls.
2506 - TFTP Fixed UDP Port:
2509 If this is defined, the environment variable tftpsrcp
2510 is used to supply the TFTP UDP source port value.
2511 If tftpsrcp isn't defined, the normal pseudo-random port
2512 number generator is used.
2514 Also, the environment variable tftpdstp is used to supply
2515 the TFTP UDP destination port value. If tftpdstp isn't
2516 defined, the normal port 69 is used.
2518 The purpose for tftpsrcp is to allow a TFTP server to
2519 blindly start the TFTP transfer using the pre-configured
2520 target IP address and UDP port. This has the effect of
2521 "punching through" the (Windows XP) firewall, allowing
2522 the remainder of the TFTP transfer to proceed normally.
2523 A better solution is to properly configure the firewall,
2524 but sometimes that is not allowed.
2529 This enables a generic 'hash' command which can produce
2530 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2534 Enable the hash verify command (hash -v). This adds to code
2537 CONFIG_SHA1 - support SHA1 hashing
2538 CONFIG_SHA256 - support SHA256 hashing
2540 Note: There is also a sha1sum command, which should perhaps
2541 be deprecated in favour of 'hash sha1'.
2543 - Show boot progress:
2544 CONFIG_SHOW_BOOT_PROGRESS
2546 Defining this option allows to add some board-
2547 specific code (calling a user-provided function
2548 "show_boot_progress(int)") that enables you to show
2549 the system's boot progress on some display (for
2550 example, some LED's) on your board. At the moment,
2551 the following checkpoints are implemented:
2553 - Detailed boot stage timing
2555 Define this option to get detailed timing of each stage
2556 of the boot process.
2558 CONFIG_BOOTSTAGE_USER_COUNT
2559 This is the number of available user bootstage records.
2560 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2561 a new ID will be allocated from this stash. If you exceed
2562 the limit, recording will stop.
2564 CONFIG_BOOTSTAGE_REPORT
2565 Define this to print a report before boot, similar to this:
2567 Timer summary in microseconds:
2570 3,575,678 3,575,678 board_init_f start
2571 3,575,695 17 arch_cpu_init A9
2572 3,575,777 82 arch_cpu_init done
2573 3,659,598 83,821 board_init_r start
2574 3,910,375 250,777 main_loop
2575 29,916,167 26,005,792 bootm_start
2576 30,361,327 445,160 start_kernel
2578 CONFIG_CMD_BOOTSTAGE
2579 Add a 'bootstage' command which supports printing a report
2580 and un/stashing of bootstage data.
2582 CONFIG_BOOTSTAGE_FDT
2583 Stash the bootstage information in the FDT. A root 'bootstage'
2584 node is created with each bootstage id as a child. Each child
2585 has a 'name' property and either 'mark' containing the
2586 mark time in microsecond, or 'accum' containing the
2587 accumulated time for that bootstage id in microseconds.
2592 name = "board_init_f";
2601 Code in the Linux kernel can find this in /proc/devicetree.
2603 Legacy uImage format:
2606 1 common/cmd_bootm.c before attempting to boot an image
2607 -1 common/cmd_bootm.c Image header has bad magic number
2608 2 common/cmd_bootm.c Image header has correct magic number
2609 -2 common/cmd_bootm.c Image header has bad checksum
2610 3 common/cmd_bootm.c Image header has correct checksum
2611 -3 common/cmd_bootm.c Image data has bad checksum
2612 4 common/cmd_bootm.c Image data has correct checksum
2613 -4 common/cmd_bootm.c Image is for unsupported architecture
2614 5 common/cmd_bootm.c Architecture check OK
2615 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2616 6 common/cmd_bootm.c Image Type check OK
2617 -6 common/cmd_bootm.c gunzip uncompression error
2618 -7 common/cmd_bootm.c Unimplemented compression type
2619 7 common/cmd_bootm.c Uncompression OK
2620 8 common/cmd_bootm.c No uncompress/copy overwrite error
2621 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2623 9 common/image.c Start initial ramdisk verification
2624 -10 common/image.c Ramdisk header has bad magic number
2625 -11 common/image.c Ramdisk header has bad checksum
2626 10 common/image.c Ramdisk header is OK
2627 -12 common/image.c Ramdisk data has bad checksum
2628 11 common/image.c Ramdisk data has correct checksum
2629 12 common/image.c Ramdisk verification complete, start loading
2630 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2631 13 common/image.c Start multifile image verification
2632 14 common/image.c No initial ramdisk, no multifile, continue.
2634 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2636 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2637 -31 post/post.c POST test failed, detected by post_output_backlog()
2638 -32 post/post.c POST test failed, detected by post_run_single()
2640 34 common/cmd_doc.c before loading a Image from a DOC device
2641 -35 common/cmd_doc.c Bad usage of "doc" command
2642 35 common/cmd_doc.c correct usage of "doc" command
2643 -36 common/cmd_doc.c No boot device
2644 36 common/cmd_doc.c correct boot device
2645 -37 common/cmd_doc.c Unknown Chip ID on boot device
2646 37 common/cmd_doc.c correct chip ID found, device available
2647 -38 common/cmd_doc.c Read Error on boot device
2648 38 common/cmd_doc.c reading Image header from DOC device OK
2649 -39 common/cmd_doc.c Image header has bad magic number
2650 39 common/cmd_doc.c Image header has correct magic number
2651 -40 common/cmd_doc.c Error reading Image from DOC device
2652 40 common/cmd_doc.c Image header has correct magic number
2653 41 common/cmd_ide.c before loading a Image from a IDE device
2654 -42 common/cmd_ide.c Bad usage of "ide" command
2655 42 common/cmd_ide.c correct usage of "ide" command
2656 -43 common/cmd_ide.c No boot device
2657 43 common/cmd_ide.c boot device found
2658 -44 common/cmd_ide.c Device not available
2659 44 common/cmd_ide.c Device available
2660 -45 common/cmd_ide.c wrong partition selected
2661 45 common/cmd_ide.c partition selected
2662 -46 common/cmd_ide.c Unknown partition table
2663 46 common/cmd_ide.c valid partition table found
2664 -47 common/cmd_ide.c Invalid partition type
2665 47 common/cmd_ide.c correct partition type
2666 -48 common/cmd_ide.c Error reading Image Header on boot device
2667 48 common/cmd_ide.c reading Image Header from IDE device OK
2668 -49 common/cmd_ide.c Image header has bad magic number
2669 49 common/cmd_ide.c Image header has correct magic number
2670 -50 common/cmd_ide.c Image header has bad checksum
2671 50 common/cmd_ide.c Image header has correct checksum
2672 -51 common/cmd_ide.c Error reading Image from IDE device
2673 51 common/cmd_ide.c reading Image from IDE device OK
2674 52 common/cmd_nand.c before loading a Image from a NAND device
2675 -53 common/cmd_nand.c Bad usage of "nand" command
2676 53 common/cmd_nand.c correct usage of "nand" command
2677 -54 common/cmd_nand.c No boot device
2678 54 common/cmd_nand.c boot device found
2679 -55 common/cmd_nand.c Unknown Chip ID on boot device
2680 55 common/cmd_nand.c correct chip ID found, device available
2681 -56 common/cmd_nand.c Error reading Image Header on boot device
2682 56 common/cmd_nand.c reading Image Header from NAND device OK
2683 -57 common/cmd_nand.c Image header has bad magic number
2684 57 common/cmd_nand.c Image header has correct magic number
2685 -58 common/cmd_nand.c Error reading Image from NAND device
2686 58 common/cmd_nand.c reading Image from NAND device OK
2688 -60 common/env_common.c Environment has a bad CRC, using default
2690 64 net/eth.c starting with Ethernet configuration.
2691 -64 net/eth.c no Ethernet found.
2692 65 net/eth.c Ethernet found.
2694 -80 common/cmd_net.c usage wrong
2695 80 common/cmd_net.c before calling NetLoop()
2696 -81 common/cmd_net.c some error in NetLoop() occurred
2697 81 common/cmd_net.c NetLoop() back without error
2698 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2699 82 common/cmd_net.c trying automatic boot
2700 83 common/cmd_net.c running "source" command
2701 -83 common/cmd_net.c some error in automatic boot or "source" command
2702 84 common/cmd_net.c end without errors
2707 100 common/cmd_bootm.c Kernel FIT Image has correct format
2708 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2709 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2710 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2711 102 common/cmd_bootm.c Kernel unit name specified
2712 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2713 103 common/cmd_bootm.c Found configuration node
2714 104 common/cmd_bootm.c Got kernel subimage node offset
2715 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2716 105 common/cmd_bootm.c Kernel subimage hash verification OK
2717 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2718 106 common/cmd_bootm.c Architecture check OK
2719 -106 common/cmd_bootm.c Kernel subimage has wrong type
2720 107 common/cmd_bootm.c Kernel subimage type OK
2721 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2722 108 common/cmd_bootm.c Got kernel subimage data/size
2723 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2724 -109 common/cmd_bootm.c Can't get kernel subimage type
2725 -110 common/cmd_bootm.c Can't get kernel subimage comp
2726 -111 common/cmd_bootm.c Can't get kernel subimage os
2727 -112 common/cmd_bootm.c Can't get kernel subimage load address
2728 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2730 120 common/image.c Start initial ramdisk verification
2731 -120 common/image.c Ramdisk FIT image has incorrect format
2732 121 common/image.c Ramdisk FIT image has correct format
2733 122 common/image.c No ramdisk subimage unit name, using configuration
2734 -122 common/image.c Can't get configuration for ramdisk subimage
2735 123 common/image.c Ramdisk unit name specified
2736 -124 common/image.c Can't get ramdisk subimage node offset
2737 125 common/image.c Got ramdisk subimage node offset
2738 -125 common/image.c Ramdisk subimage hash verification failed
2739 126 common/image.c Ramdisk subimage hash verification OK
2740 -126 common/image.c Ramdisk subimage for unsupported architecture
2741 127 common/image.c Architecture check OK
2742 -127 common/image.c Can't get ramdisk subimage data/size
2743 128 common/image.c Got ramdisk subimage data/size
2744 129 common/image.c Can't get ramdisk load address
2745 -129 common/image.c Got ramdisk load address
2747 -130 common/cmd_doc.c Incorrect FIT image format
2748 131 common/cmd_doc.c FIT image format OK
2750 -140 common/cmd_ide.c Incorrect FIT image format
2751 141 common/cmd_ide.c FIT image format OK
2753 -150 common/cmd_nand.c Incorrect FIT image format
2754 151 common/cmd_nand.c FIT image format OK
2756 - FIT image support:
2758 Enable support for the FIT uImage format.
2760 CONFIG_FIT_BEST_MATCH
2761 When no configuration is explicitly selected, default to the
2762 one whose fdt's compatibility field best matches that of
2763 U-Boot itself. A match is considered "best" if it matches the
2764 most specific compatibility entry of U-Boot's fdt's root node.
2765 The order of entries in the configuration's fdt is ignored.
2767 - Standalone program support:
2768 CONFIG_STANDALONE_LOAD_ADDR
2770 This option defines a board specific value for the
2771 address where standalone program gets loaded, thus
2772 overwriting the architecture dependent default
2775 - Frame Buffer Address:
2778 Define CONFIG_FB_ADDR if you want to use specific
2779 address for frame buffer. This is typically the case
2780 when using a graphics controller has separate video
2781 memory. U-Boot will then place the frame buffer at
2782 the given address instead of dynamically reserving it
2783 in system RAM by calling lcd_setmem(), which grabs
2784 the memory for the frame buffer depending on the
2785 configured panel size.
2787 Please see board_init_f function.
2789 - Automatic software updates via TFTP server
2791 CONFIG_UPDATE_TFTP_CNT_MAX
2792 CONFIG_UPDATE_TFTP_MSEC_MAX
2794 These options enable and control the auto-update feature;
2795 for a more detailed description refer to doc/README.update.
2797 - MTD Support (mtdparts command, UBI support)
2800 Adds the MTD device infrastructure from the Linux kernel.
2801 Needed for mtdparts command support.
2803 CONFIG_MTD_PARTITIONS
2805 Adds the MTD partitioning infrastructure from the Linux
2806 kernel. Needed for UBI support.
2811 Adds commands for interacting with MTD partitions formatted
2812 with the UBI flash translation layer
2814 Requires also defining CONFIG_RBTREE
2816 CONFIG_UBI_SILENCE_MSG
2818 Make the verbose messages from UBI stop printing. This leaves
2819 warnings and errors enabled.
2824 Adds commands for interacting with UBI volumes formatted as
2825 UBIFS. UBIFS is read-only in u-boot.
2827 Requires UBI support as well as CONFIG_LZO
2829 CONFIG_UBIFS_SILENCE_MSG
2831 Make the verbose messages from UBIFS stop printing. This leaves
2832 warnings and errors enabled.
2836 Enable building of SPL globally.
2839 LDSCRIPT for linking the SPL binary.
2841 CONFIG_SPL_MAX_FOOTPRINT
2842 Maximum size in memory allocated to the SPL, BSS included.
2843 When defined, the linker checks that the actual memory
2844 used by SPL from _start to __bss_end does not exceed it.
2845 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2846 must not be both defined at the same time.
2849 Maximum size of the SPL image (text, data, rodata, and
2850 linker lists sections), BSS excluded.
2851 When defined, the linker checks that the actual size does
2854 CONFIG_SPL_TEXT_BASE
2855 TEXT_BASE for linking the SPL binary.
2857 CONFIG_SPL_RELOC_TEXT_BASE
2858 Address to relocate to. If unspecified, this is equal to
2859 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2861 CONFIG_SPL_BSS_START_ADDR
2862 Link address for the BSS within the SPL binary.
2864 CONFIG_SPL_BSS_MAX_SIZE
2865 Maximum size in memory allocated to the SPL BSS.
2866 When defined, the linker checks that the actual memory used
2867 by SPL from __bss_start to __bss_end does not exceed it.
2868 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2869 must not be both defined at the same time.
2872 Adress of the start of the stack SPL will use
2874 CONFIG_SPL_RELOC_STACK
2875 Adress of the start of the stack SPL will use after
2876 relocation. If unspecified, this is equal to
2879 CONFIG_SYS_SPL_MALLOC_START
2880 Starting address of the malloc pool used in SPL.
2882 CONFIG_SYS_SPL_MALLOC_SIZE
2883 The size of the malloc pool used in SPL.
2885 CONFIG_SPL_FRAMEWORK
2886 Enable the SPL framework under common/. This framework
2887 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2888 NAND loading of the Linux Kernel.
2890 CONFIG_SPL_DISPLAY_PRINT
2891 For ARM, enable an optional function to print more information
2892 about the running system.
2894 CONFIG_SPL_INIT_MINIMAL
2895 Arch init code should be built for a very small image
2897 CONFIG_SPL_LIBCOMMON_SUPPORT
2898 Support for common/libcommon.o in SPL binary
2900 CONFIG_SPL_LIBDISK_SUPPORT
2901 Support for disk/libdisk.o in SPL binary
2903 CONFIG_SPL_I2C_SUPPORT
2904 Support for drivers/i2c/libi2c.o in SPL binary
2906 CONFIG_SPL_GPIO_SUPPORT
2907 Support for drivers/gpio/libgpio.o in SPL binary
2909 CONFIG_SPL_MMC_SUPPORT
2910 Support for drivers/mmc/libmmc.o in SPL binary
2912 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2913 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2914 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2915 Address, size and partition on the MMC to load U-Boot from
2916 when the MMC is being used in raw mode.
2918 CONFIG_SPL_FAT_SUPPORT
2919 Support for fs/fat/libfat.o in SPL binary
2921 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2922 Filename to read to load U-Boot when reading from FAT
2924 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2925 Set this for NAND SPL on PPC mpc83xx targets, so that
2926 start.S waits for the rest of the SPL to load before
2927 continuing (the hardware starts execution after just
2928 loading the first page rather than the full 4K).
2930 CONFIG_SPL_NAND_BASE
2931 Include nand_base.c in the SPL. Requires
2932 CONFIG_SPL_NAND_DRIVERS.
2934 CONFIG_SPL_NAND_DRIVERS
2935 SPL uses normal NAND drivers, not minimal drivers.
2938 Include standard software ECC in the SPL
2940 CONFIG_SPL_NAND_SIMPLE
2941 Support for NAND boot using simple NAND drivers that
2942 expose the cmd_ctrl() interface.
2944 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2945 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2946 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2947 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2948 CONFIG_SYS_NAND_ECCBYTES
2949 Defines the size and behavior of the NAND that SPL uses
2952 CONFIG_SYS_NAND_U_BOOT_OFFS
2953 Location in NAND to read U-Boot from
2955 CONFIG_SYS_NAND_U_BOOT_DST
2956 Location in memory to load U-Boot to
2958 CONFIG_SYS_NAND_U_BOOT_SIZE
2959 Size of image to load
2961 CONFIG_SYS_NAND_U_BOOT_START
2962 Entry point in loaded image to jump to
2964 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2965 Define this if you need to first read the OOB and then the
2966 data. This is used for example on davinci plattforms.
2968 CONFIG_SPL_OMAP3_ID_NAND
2969 Support for an OMAP3-specific set of functions to return the
2970 ID and MFR of the first attached NAND chip, if present.
2972 CONFIG_SPL_SERIAL_SUPPORT
2973 Support for drivers/serial/libserial.o in SPL binary
2975 CONFIG_SPL_SPI_FLASH_SUPPORT
2976 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2978 CONFIG_SPL_SPI_SUPPORT
2979 Support for drivers/spi/libspi.o in SPL binary
2981 CONFIG_SPL_RAM_DEVICE
2982 Support for running image already present in ram, in SPL binary
2984 CONFIG_SPL_LIBGENERIC_SUPPORT
2985 Support for lib/libgeneric.o in SPL binary
2988 Image offset to which the SPL should be padded before appending
2989 the SPL payload. By default, this is defined as
2990 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2991 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2992 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2995 Final target image containing SPL and payload. Some SPLs
2996 use an arch-specific makefile fragment instead, for
2997 example if more than one image needs to be produced.
3002 [so far only for SMDK2400 boards]
3004 - Modem support enable:
3005 CONFIG_MODEM_SUPPORT
3007 - RTS/CTS Flow control enable:
3010 - Modem debug support:
3011 CONFIG_MODEM_SUPPORT_DEBUG
3013 Enables debugging stuff (char screen[1024], dbg())
3014 for modem support. Useful only with BDI2000.
3016 - Interrupt support (PPC):
3018 There are common interrupt_init() and timer_interrupt()
3019 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3020 for CPU specific initialization. interrupt_init_cpu()
3021 should set decrementer_count to appropriate value. If
3022 CPU resets decrementer automatically after interrupt
3023 (ppc4xx) it should set decrementer_count to zero.
3024 timer_interrupt() calls timer_interrupt_cpu() for CPU
3025 specific handling. If board has watchdog / status_led
3026 / other_activity_monitor it works automatically from
3027 general timer_interrupt().
3031 In the target system modem support is enabled when a
3032 specific key (key combination) is pressed during
3033 power-on. Otherwise U-Boot will boot normally
3034 (autoboot). The key_pressed() function is called from
3035 board_init(). Currently key_pressed() is a dummy
3036 function, returning 1 and thus enabling modem
3039 If there are no modem init strings in the
3040 environment, U-Boot proceed to autoboot; the
3041 previous output (banner, info printfs) will be
3044 See also: doc/README.Modem
3046 Board initialization settings:
3047 ------------------------------
3049 During Initialization u-boot calls a number of board specific functions
3050 to allow the preparation of board specific prerequisites, e.g. pin setup
3051 before drivers are initialized. To enable these callbacks the
3052 following configuration macros have to be defined. Currently this is
3053 architecture specific, so please check arch/your_architecture/lib/board.c
3054 typically in board_init_f() and board_init_r().
3056 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3057 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3058 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3059 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3061 Configuration Settings:
3062 -----------------------
3064 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3065 undefine this when you're short of memory.
3067 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3068 width of the commands listed in the 'help' command output.
3070 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3071 prompt for user input.
3073 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3075 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3077 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3079 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3080 the application (usually a Linux kernel) when it is
3083 - CONFIG_SYS_BAUDRATE_TABLE:
3084 List of legal baudrate settings for this board.
3086 - CONFIG_SYS_CONSOLE_INFO_QUIET
3087 Suppress display of console information at boot.
3089 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3090 If the board specific function
3091 extern int overwrite_console (void);
3092 returns 1, the stdin, stderr and stdout are switched to the
3093 serial port, else the settings in the environment are used.
3095 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3096 Enable the call to overwrite_console().
3098 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3099 Enable overwrite of previous console environment settings.
3101 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3102 Begin and End addresses of the area used by the
3105 - CONFIG_SYS_ALT_MEMTEST:
3106 Enable an alternate, more extensive memory test.
3108 - CONFIG_SYS_MEMTEST_SCRATCH:
3109 Scratch address used by the alternate memory test
3110 You only need to set this if address zero isn't writeable
3112 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3113 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3114 this specified memory area will get subtracted from the top
3115 (end) of RAM and won't get "touched" at all by U-Boot. By
3116 fixing up gd->ram_size the Linux kernel should gets passed
3117 the now "corrected" memory size and won't touch it either.
3118 This should work for arch/ppc and arch/powerpc. Only Linux
3119 board ports in arch/powerpc with bootwrapper support that
3120 recalculate the memory size from the SDRAM controller setup
3121 will have to get fixed in Linux additionally.
3123 This option can be used as a workaround for the 440EPx/GRx
3124 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3127 WARNING: Please make sure that this value is a multiple of
3128 the Linux page size (normally 4k). If this is not the case,
3129 then the end address of the Linux memory will be located at a
3130 non page size aligned address and this could cause major
3133 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3134 Enable temporary baudrate change while serial download
3136 - CONFIG_SYS_SDRAM_BASE:
3137 Physical start address of SDRAM. _Must_ be 0 here.
3139 - CONFIG_SYS_MBIO_BASE:
3140 Physical start address of Motherboard I/O (if using a
3143 - CONFIG_SYS_FLASH_BASE:
3144 Physical start address of Flash memory.
3146 - CONFIG_SYS_MONITOR_BASE:
3147 Physical start address of boot monitor code (set by
3148 make config files to be same as the text base address
3149 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3150 CONFIG_SYS_FLASH_BASE when booting from flash.
3152 - CONFIG_SYS_MONITOR_LEN:
3153 Size of memory reserved for monitor code, used to
3154 determine _at_compile_time_ (!) if the environment is
3155 embedded within the U-Boot image, or in a separate
3158 - CONFIG_SYS_MALLOC_LEN:
3159 Size of DRAM reserved for malloc() use.
3161 - CONFIG_SYS_BOOTM_LEN:
3162 Normally compressed uImages are limited to an
3163 uncompressed size of 8 MBytes. If this is not enough,
3164 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3165 to adjust this setting to your needs.
3167 - CONFIG_SYS_BOOTMAPSZ:
3168 Maximum size of memory mapped by the startup code of
3169 the Linux kernel; all data that must be processed by
3170 the Linux kernel (bd_info, boot arguments, FDT blob if
3171 used) must be put below this limit, unless "bootm_low"
3172 enviroment variable is defined and non-zero. In such case
3173 all data for the Linux kernel must be between "bootm_low"
3174 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3175 variable "bootm_mapsize" will override the value of
3176 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3177 then the value in "bootm_size" will be used instead.
3179 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3180 Enable initrd_high functionality. If defined then the
3181 initrd_high feature is enabled and the bootm ramdisk subcommand
3184 - CONFIG_SYS_BOOT_GET_CMDLINE:
3185 Enables allocating and saving kernel cmdline in space between
3186 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3188 - CONFIG_SYS_BOOT_GET_KBD:
3189 Enables allocating and saving a kernel copy of the bd_info in
3190 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3192 - CONFIG_SYS_MAX_FLASH_BANKS:
3193 Max number of Flash memory banks
3195 - CONFIG_SYS_MAX_FLASH_SECT:
3196 Max number of sectors on a Flash chip
3198 - CONFIG_SYS_FLASH_ERASE_TOUT:
3199 Timeout for Flash erase operations (in ms)
3201 - CONFIG_SYS_FLASH_WRITE_TOUT:
3202 Timeout for Flash write operations (in ms)
3204 - CONFIG_SYS_FLASH_LOCK_TOUT
3205 Timeout for Flash set sector lock bit operation (in ms)
3207 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3208 Timeout for Flash clear lock bits operation (in ms)
3210 - CONFIG_SYS_FLASH_PROTECTION
3211 If defined, hardware flash sectors protection is used
3212 instead of U-Boot software protection.
3214 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3216 Enable TFTP transfers directly to flash memory;
3217 without this option such a download has to be
3218 performed in two steps: (1) download to RAM, and (2)
3219 copy from RAM to flash.
3221 The two-step approach is usually more reliable, since
3222 you can check if the download worked before you erase
3223 the flash, but in some situations (when system RAM is
3224 too limited to allow for a temporary copy of the
3225 downloaded image) this option may be very useful.
3227 - CONFIG_SYS_FLASH_CFI:
3228 Define if the flash driver uses extra elements in the
3229 common flash structure for storing flash geometry.
3231 - CONFIG_FLASH_CFI_DRIVER
3232 This option also enables the building of the cfi_flash driver
3233 in the drivers directory
3235 - CONFIG_FLASH_CFI_MTD
3236 This option enables the building of the cfi_mtd driver
3237 in the drivers directory. The driver exports CFI flash
3240 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3241 Use buffered writes to flash.
3243 - CONFIG_FLASH_SPANSION_S29WS_N
3244 s29ws-n MirrorBit flash has non-standard addresses for buffered
3247 - CONFIG_SYS_FLASH_QUIET_TEST
3248 If this option is defined, the common CFI flash doesn't
3249 print it's warning upon not recognized FLASH banks. This
3250 is useful, if some of the configured banks are only
3251 optionally available.
3253 - CONFIG_FLASH_SHOW_PROGRESS
3254 If defined (must be an integer), print out countdown
3255 digits and dots. Recommended value: 45 (9..1) for 80
3256 column displays, 15 (3..1) for 40 column displays.
3258 - CONFIG_FLASH_VERIFY
3259 If defined, the content of the flash (destination) is compared
3260 against the source after the write operation. An error message
3261 will be printed when the contents are not identical.
3262 Please note that this option is useless in nearly all cases,
3263 since such flash programming errors usually are detected earlier
3264 while unprotecting/erasing/programming. Please only enable
3265 this option if you really know what you are doing.
3267 - CONFIG_SYS_RX_ETH_BUFFER:
3268 Defines the number of Ethernet receive buffers. On some
3269 Ethernet controllers it is recommended to set this value
3270 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3271 buffers can be full shortly after enabling the interface
3272 on high Ethernet traffic.
3273 Defaults to 4 if not defined.
3275 - CONFIG_ENV_MAX_ENTRIES
3277 Maximum number of entries in the hash table that is used
3278 internally to store the environment settings. The default
3279 setting is supposed to be generous and should work in most
3280 cases. This setting can be used to tune behaviour; see
3281 lib/hashtable.c for details.
3283 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3284 - CONFIG_ENV_FLAGS_LIST_STATIC
3285 Enable validation of the values given to enviroment variables when
3286 calling env set. Variables can be restricted to only decimal,
3287 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3288 the variables can also be restricted to IP address or MAC address.
3290 The format of the list is:
3291 type_attribute = [s|d|x|b|i|m]
3292 access_atribute = [a|r|o|c]
3293 attributes = type_attribute[access_atribute]
3294 entry = variable_name[:attributes]
3297 The type attributes are:
3298 s - String (default)
3301 b - Boolean ([1yYtT|0nNfF])
3305 The access attributes are:
3311 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3312 Define this to a list (string) to define the ".flags"
3313 envirnoment variable in the default or embedded environment.
3315 - CONFIG_ENV_FLAGS_LIST_STATIC
3316 Define this to a list (string) to define validation that
3317 should be done if an entry is not found in the ".flags"
3318 environment variable. To override a setting in the static
3319 list, simply add an entry for the same variable name to the
3322 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3323 If defined, don't allow the -f switch to env set override variable
3326 - CONFIG_SYS_GENERIC_BOARD
3327 This selects the architecture-generic board system instead of the
3328 architecture-specific board files. It is intended to move boards
3329 to this new framework over time. Defining this will disable the
3330 arch/foo/lib/board.c file and use common/board_f.c and
3331 common/board_r.c instead. To use this option your architecture
3332 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3333 its config.mk file). If you find problems enabling this option on
3334 your board please report the problem and send patches!
3336 - CONFIG_SYS_SYM_OFFSETS
3337 This is set by architectures that use offsets for link symbols
3338 instead of absolute values. So bss_start is obtained using an
3339 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3340 directly. You should not need to touch this setting.
3343 The following definitions that deal with the placement and management
3344 of environment data (variable area); in general, we support the
3345 following configurations:
3347 - CONFIG_BUILD_ENVCRC:
3349 Builds up envcrc with the target environment so that external utils
3350 may easily extract it and embed it in final U-Boot images.
3352 - CONFIG_ENV_IS_IN_FLASH:
3354 Define this if the environment is in flash memory.
3356 a) The environment occupies one whole flash sector, which is
3357 "embedded" in the text segment with the U-Boot code. This
3358 happens usually with "bottom boot sector" or "top boot
3359 sector" type flash chips, which have several smaller
3360 sectors at the start or the end. For instance, such a
3361 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3362 such a case you would place the environment in one of the
3363 4 kB sectors - with U-Boot code before and after it. With
3364 "top boot sector" type flash chips, you would put the
3365 environment in one of the last sectors, leaving a gap
3366 between U-Boot and the environment.
3368 - CONFIG_ENV_OFFSET:
3370 Offset of environment data (variable area) to the
3371 beginning of flash memory; for instance, with bottom boot
3372 type flash chips the second sector can be used: the offset
3373 for this sector is given here.
3375 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3379 This is just another way to specify the start address of
3380 the flash sector containing the environment (instead of
3383 - CONFIG_ENV_SECT_SIZE:
3385 Size of the sector containing the environment.
3388 b) Sometimes flash chips have few, equal sized, BIG sectors.
3389 In such a case you don't want to spend a whole sector for
3394 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3395 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3396 of this flash sector for the environment. This saves
3397 memory for the RAM copy of the environment.
3399 It may also save flash memory if you decide to use this
3400 when your environment is "embedded" within U-Boot code,
3401 since then the remainder of the flash sector could be used
3402 for U-Boot code. It should be pointed out that this is
3403 STRONGLY DISCOURAGED from a robustness point of view:
3404 updating the environment in flash makes it always
3405 necessary to erase the WHOLE sector. If something goes
3406 wrong before the contents has been restored from a copy in
3407 RAM, your target system will be dead.
3409 - CONFIG_ENV_ADDR_REDUND
3410 CONFIG_ENV_SIZE_REDUND
3412 These settings describe a second storage area used to hold
3413 a redundant copy of the environment data, so that there is
3414 a valid backup copy in case there is a power failure during
3415 a "saveenv" operation.
3417 BE CAREFUL! Any changes to the flash layout, and some changes to the
3418 source code will make it necessary to adapt <board>/u-boot.lds*
3422 - CONFIG_ENV_IS_IN_NVRAM:
3424 Define this if you have some non-volatile memory device
3425 (NVRAM, battery buffered SRAM) which you want to use for the
3431 These two #defines are used to determine the memory area you
3432 want to use for environment. It is assumed that this memory
3433 can just be read and written to, without any special
3436 BE CAREFUL! The first access to the environment happens quite early
3437 in U-Boot initalization (when we try to get the setting of for the
3438 console baudrate). You *MUST* have mapped your NVRAM area then, or
3441 Please note that even with NVRAM we still use a copy of the
3442 environment in RAM: we could work on NVRAM directly, but we want to
3443 keep settings there always unmodified except somebody uses "saveenv"
3444 to save the current settings.
3447 - CONFIG_ENV_IS_IN_EEPROM:
3449 Use this if you have an EEPROM or similar serial access
3450 device and a driver for it.
3452 - CONFIG_ENV_OFFSET:
3455 These two #defines specify the offset and size of the
3456 environment area within the total memory of your EEPROM.
3458 - CONFIG_SYS_I2C_EEPROM_ADDR:
3459 If defined, specified the chip address of the EEPROM device.
3460 The default address is zero.
3462 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3463 If defined, the number of bits used to address bytes in a
3464 single page in the EEPROM device. A 64 byte page, for example
3465 would require six bits.
3467 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3468 If defined, the number of milliseconds to delay between
3469 page writes. The default is zero milliseconds.
3471 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3472 The length in bytes of the EEPROM memory array address. Note
3473 that this is NOT the chip address length!
3475 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3476 EEPROM chips that implement "address overflow" are ones
3477 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3478 address and the extra bits end up in the "chip address" bit
3479 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3482 Note that we consider the length of the address field to
3483 still be one byte because the extra address bits are hidden
3484 in the chip address.
3486 - CONFIG_SYS_EEPROM_SIZE:
3487 The size in bytes of the EEPROM device.
3489 - CONFIG_ENV_EEPROM_IS_ON_I2C
3490 define this, if you have I2C and SPI activated, and your
3491 EEPROM, which holds the environment, is on the I2C bus.
3493 - CONFIG_I2C_ENV_EEPROM_BUS
3494 if you have an Environment on an EEPROM reached over
3495 I2C muxes, you can define here, how to reach this
3496 EEPROM. For example:
3498 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3500 EEPROM which holds the environment, is reached over
3501 a pca9547 i2c mux with address 0x70, channel 3.
3503 - CONFIG_ENV_IS_IN_DATAFLASH:
3505 Define this if you have a DataFlash memory device which you
3506 want to use for the environment.
3508 - CONFIG_ENV_OFFSET:
3512 These three #defines specify the offset and size of the
3513 environment area within the total memory of your DataFlash placed
3514 at the specified address.
3516 - CONFIG_ENV_IS_IN_REMOTE:
3518 Define this if you have a remote memory space which you
3519 want to use for the local device's environment.
3524 These two #defines specify the address and size of the
3525 environment area within the remote memory space. The
3526 local device can get the environment from remote memory
3527 space by SRIO or PCIE links.
3529 BE CAREFUL! For some special cases, the local device can not use
3530 "saveenv" command. For example, the local device will get the
3531 environment stored in a remote NOR flash by SRIO or PCIE link,
3532 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3534 - CONFIG_ENV_IS_IN_NAND:
3536 Define this if you have a NAND device which you want to use
3537 for the environment.
3539 - CONFIG_ENV_OFFSET:
3542 These two #defines specify the offset and size of the environment
3543 area within the first NAND device. CONFIG_ENV_OFFSET must be
3544 aligned to an erase block boundary.
3546 - CONFIG_ENV_OFFSET_REDUND (optional):
3548 This setting describes a second storage area of CONFIG_ENV_SIZE
3549 size used to hold a redundant copy of the environment data, so
3550 that there is a valid backup copy in case there is a power failure
3551 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3552 aligned to an erase block boundary.
3554 - CONFIG_ENV_RANGE (optional):
3556 Specifies the length of the region in which the environment
3557 can be written. This should be a multiple of the NAND device's
3558 block size. Specifying a range with more erase blocks than
3559 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3560 the range to be avoided.
3562 - CONFIG_ENV_OFFSET_OOB (optional):
3564 Enables support for dynamically retrieving the offset of the
3565 environment from block zero's out-of-band data. The
3566 "nand env.oob" command can be used to record this offset.
3567 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3568 using CONFIG_ENV_OFFSET_OOB.
3570 - CONFIG_NAND_ENV_DST
3572 Defines address in RAM to which the nand_spl code should copy the
3573 environment. If redundant environment is used, it will be copied to
3574 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3576 - CONFIG_ENV_IS_IN_UBI:
3578 Define this if you have an UBI volume that you want to use for the
3579 environment. This has the benefit of wear-leveling the environment
3580 accesses, which is important on NAND.
3582 - CONFIG_ENV_UBI_PART:
3584 Define this to a string that is the mtd partition containing the UBI.
3586 - CONFIG_ENV_UBI_VOLUME:
3588 Define this to the name of the volume that you want to store the
3591 - CONFIG_ENV_UBI_VOLUME_REDUND:
3593 Define this to the name of another volume to store a second copy of
3594 the environment in. This will enable redundant environments in UBI.
3595 It is assumed that both volumes are in the same MTD partition.
3597 - CONFIG_UBI_SILENCE_MSG
3598 - CONFIG_UBIFS_SILENCE_MSG
3600 You will probably want to define these to avoid a really noisy system
3601 when storing the env in UBI.
3603 - CONFIG_SYS_SPI_INIT_OFFSET
3605 Defines offset to the initial SPI buffer area in DPRAM. The
3606 area is used at an early stage (ROM part) if the environment
3607 is configured to reside in the SPI EEPROM: We need a 520 byte
3608 scratch DPRAM area. It is used between the two initialization
3609 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3610 to be a good choice since it makes it far enough from the
3611 start of the data area as well as from the stack pointer.
3613 Please note that the environment is read-only until the monitor
3614 has been relocated to RAM and a RAM copy of the environment has been
3615 created; also, when using EEPROM you will have to use getenv_f()
3616 until then to read environment variables.
3618 The environment is protected by a CRC32 checksum. Before the monitor
3619 is relocated into RAM, as a result of a bad CRC you will be working
3620 with the compiled-in default environment - *silently*!!! [This is
3621 necessary, because the first environment variable we need is the
3622 "baudrate" setting for the console - if we have a bad CRC, we don't
3623 have any device yet where we could complain.]
3625 Note: once the monitor has been relocated, then it will complain if
3626 the default environment is used; a new CRC is computed as soon as you
3627 use the "saveenv" command to store a valid environment.
3629 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3630 Echo the inverted Ethernet link state to the fault LED.
3632 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3633 also needs to be defined.
3635 - CONFIG_SYS_FAULT_MII_ADDR:
3636 MII address of the PHY to check for the Ethernet link state.
3638 - CONFIG_NS16550_MIN_FUNCTIONS:
3639 Define this if you desire to only have use of the NS16550_init
3640 and NS16550_putc functions for the serial driver located at
3641 drivers/serial/ns16550.c. This option is useful for saving
3642 space for already greatly restricted images, including but not
3643 limited to NAND_SPL configurations.
3645 - CONFIG_DISPLAY_BOARDINFO
3646 Display information about the board that U-Boot is running on
3647 when U-Boot starts up. The board function checkboard() is called
3650 - CONFIG_DISPLAY_BOARDINFO_LATE
3651 Similar to the previous option, but display this information
3652 later, once stdio is running and output goes to the LCD, if
3655 Low Level (hardware related) configuration options:
3656 ---------------------------------------------------
3658 - CONFIG_SYS_CACHELINE_SIZE:
3659 Cache Line Size of the CPU.
3661 - CONFIG_SYS_DEFAULT_IMMR:
3662 Default address of the IMMR after system reset.
3664 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3665 and RPXsuper) to be able to adjust the position of
3666 the IMMR register after a reset.
3668 - CONFIG_SYS_CCSRBAR_DEFAULT:
3669 Default (power-on reset) physical address of CCSR on Freescale
3672 - CONFIG_SYS_CCSRBAR:
3673 Virtual address of CCSR. On a 32-bit build, this is typically
3674 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3676 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3677 for cross-platform code that uses that macro instead.
3679 - CONFIG_SYS_CCSRBAR_PHYS:
3680 Physical address of CCSR. CCSR can be relocated to a new
3681 physical address, if desired. In this case, this macro should
3682 be set to that address. Otherwise, it should be set to the
3683 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3684 is typically relocated on 36-bit builds. It is recommended
3685 that this macro be defined via the _HIGH and _LOW macros:
3687 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3688 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3690 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3691 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3692 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3693 used in assembly code, so it must not contain typecasts or
3694 integer size suffixes (e.g. "ULL").
3696 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3697 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3698 used in assembly code, so it must not contain typecasts or
3699 integer size suffixes (e.g. "ULL").
3701 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3702 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3703 forced to a value that ensures that CCSR is not relocated.
3705 - Floppy Disk Support:
3706 CONFIG_SYS_FDC_DRIVE_NUMBER
3708 the default drive number (default value 0)
3710 CONFIG_SYS_ISA_IO_STRIDE
3712 defines the spacing between FDC chipset registers
3715 CONFIG_SYS_ISA_IO_OFFSET
3717 defines the offset of register from address. It
3718 depends on which part of the data bus is connected to
3719 the FDC chipset. (default value 0)
3721 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3722 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3725 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3726 fdc_hw_init() is called at the beginning of the FDC
3727 setup. fdc_hw_init() must be provided by the board
3728 source code. It is used to make hardware dependant
3732 Most IDE controllers were designed to be connected with PCI
3733 interface. Only few of them were designed for AHB interface.
3734 When software is doing ATA command and data transfer to
3735 IDE devices through IDE-AHB controller, some additional
3736 registers accessing to these kind of IDE-AHB controller
3739 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3740 DO NOT CHANGE unless you know exactly what you're
3741 doing! (11-4) [MPC8xx/82xx systems only]
3743 - CONFIG_SYS_INIT_RAM_ADDR:
3745 Start address of memory area that can be used for
3746 initial data and stack; please note that this must be
3747 writable memory that is working WITHOUT special
3748 initialization, i. e. you CANNOT use normal RAM which
3749 will become available only after programming the
3750 memory controller and running certain initialization
3753 U-Boot uses the following memory types:
3754 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3755 - MPC824X: data cache
3756 - PPC4xx: data cache
3758 - CONFIG_SYS_GBL_DATA_OFFSET:
3760 Offset of the initial data structure in the memory
3761 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3762 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3763 data is located at the end of the available space
3764 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3765 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3766 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3767 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3770 On the MPC824X (or other systems that use the data
3771 cache for initial memory) the address chosen for
3772 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3773 point to an otherwise UNUSED address space between
3774 the top of RAM and the start of the PCI space.
3776 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3778 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3780 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3782 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3784 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3786 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3788 - CONFIG_SYS_OR_TIMING_SDRAM:
3791 - CONFIG_SYS_MAMR_PTA:
3792 periodic timer for refresh
3794 - CONFIG_SYS_DER: Debug Event Register (37-47)
3796 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3797 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3798 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3799 CONFIG_SYS_BR1_PRELIM:
3800 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3802 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3803 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3804 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3805 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3807 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3808 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3809 Machine Mode Register and Memory Periodic Timer
3810 Prescaler definitions (SDRAM timing)
3812 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3813 enable I2C microcode relocation patch (MPC8xx);
3814 define relocation offset in DPRAM [DSP2]
3816 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3817 enable SMC microcode relocation patch (MPC8xx);
3818 define relocation offset in DPRAM [SMC1]
3820 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3821 enable SPI microcode relocation patch (MPC8xx);
3822 define relocation offset in DPRAM [SCC4]
3824 - CONFIG_SYS_USE_OSCCLK:
3825 Use OSCM clock mode on MBX8xx board. Be careful,
3826 wrong setting might damage your board. Read
3827 doc/README.MBX before setting this variable!
3829 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3830 Offset of the bootmode word in DPRAM used by post
3831 (Power On Self Tests). This definition overrides
3832 #define'd default value in commproc.h resp.
3835 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3836 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3837 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3838 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3839 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3840 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3841 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3842 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3843 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3845 - CONFIG_PCI_DISABLE_PCIE:
3846 Disable PCI-Express on systems where it is supported but not
3849 - CONFIG_PCI_ENUM_ONLY
3850 Only scan through and get the devices on the busses.
3851 Don't do any setup work, presumably because someone or
3852 something has already done it, and we don't need to do it
3853 a second time. Useful for platforms that are pre-booted
3854 by coreboot or similar.
3857 Chip has SRIO or not
3860 Board has SRIO 1 port available
3863 Board has SRIO 2 port available
3865 - CONFIG_SYS_SRIOn_MEM_VIRT:
3866 Virtual Address of SRIO port 'n' memory region
3868 - CONFIG_SYS_SRIOn_MEM_PHYS:
3869 Physical Address of SRIO port 'n' memory region
3871 - CONFIG_SYS_SRIOn_MEM_SIZE:
3872 Size of SRIO port 'n' memory region
3874 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3875 Defined to tell the NAND controller that the NAND chip is using
3877 Not all NAND drivers use this symbol.
3878 Example of drivers that use it:
3879 - drivers/mtd/nand/ndfc.c
3880 - drivers/mtd/nand/mxc_nand.c
3882 - CONFIG_SYS_NDFC_EBC0_CFG
3883 Sets the EBC0_CFG register for the NDFC. If not defined
3884 a default value will be used.
3887 Get DDR timing information from an I2C EEPROM. Common
3888 with pluggable memory modules such as SODIMMs
3891 I2C address of the SPD EEPROM
3893 - CONFIG_SYS_SPD_BUS_NUM
3894 If SPD EEPROM is on an I2C bus other than the first
3895 one, specify here. Note that the value must resolve
3896 to something your driver can deal with.
3898 - CONFIG_SYS_DDR_RAW_TIMING
3899 Get DDR timing information from other than SPD. Common with
3900 soldered DDR chips onboard without SPD. DDR raw timing
3901 parameters are extracted from datasheet and hard-coded into
3902 header files or board specific files.
3904 - CONFIG_FSL_DDR_INTERACTIVE
3905 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3907 - CONFIG_SYS_83XX_DDR_USES_CS0
3908 Only for 83xx systems. If specified, then DDR should
3909 be configured using CS0 and CS1 instead of CS2 and CS3.
3911 - CONFIG_ETHER_ON_FEC[12]
3912 Define to enable FEC[12] on a 8xx series processor.
3914 - CONFIG_FEC[12]_PHY
3915 Define to the hardcoded PHY address which corresponds
3916 to the given FEC; i. e.
3917 #define CONFIG_FEC1_PHY 4
3918 means that the PHY with address 4 is connected to FEC1
3920 When set to -1, means to probe for first available.
3922 - CONFIG_FEC[12]_PHY_NORXERR
3923 The PHY does not have a RXERR line (RMII only).
3924 (so program the FEC to ignore it).
3927 Enable RMII mode for all FECs.
3928 Note that this is a global option, we can't
3929 have one FEC in standard MII mode and another in RMII mode.
3931 - CONFIG_CRC32_VERIFY
3932 Add a verify option to the crc32 command.
3935 => crc32 -v <address> <count> <crc32>
3937 Where address/count indicate a memory area
3938 and crc32 is the correct crc32 which the
3942 Add the "loopw" memory command. This only takes effect if
3943 the memory commands are activated globally (CONFIG_CMD_MEM).
3946 Add the "mdc" and "mwc" memory commands. These are cyclic
3951 This command will print 4 bytes (10,11,12,13) each 500 ms.
3953 => mwc.l 100 12345678 10
3954 This command will write 12345678 to address 100 all 10 ms.
3956 This only takes effect if the memory commands are activated
3957 globally (CONFIG_CMD_MEM).
3959 - CONFIG_SKIP_LOWLEVEL_INIT
3960 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3961 low level initializations (like setting up the memory
3962 controller) are omitted and/or U-Boot does not
3963 relocate itself into RAM.
3965 Normally this variable MUST NOT be defined. The only
3966 exception is when U-Boot is loaded (to RAM) by some
3967 other boot loader or by a debugger which performs
3968 these initializations itself.
3971 Modifies the behaviour of start.S when compiling a loader
3972 that is executed before the actual U-Boot. E.g. when
3973 compiling a NAND SPL.
3975 - CONFIG_ARCH_MAP_SYSMEM
3976 Generally U-Boot (and in particular the md command) uses
3977 effective address. It is therefore not necessary to regard
3978 U-Boot address as virtual addresses that need to be translated
3979 to physical addresses. However, sandbox requires this, since
3980 it maintains its own little RAM buffer which contains all
3981 addressable memory. This option causes some memory accesses
3982 to be mapped through map_sysmem() / unmap_sysmem().
3984 - CONFIG_USE_ARCH_MEMCPY
3985 CONFIG_USE_ARCH_MEMSET
3986 If these options are used a optimized version of memcpy/memset will
3987 be used if available. These functions may be faster under some
3988 conditions but may increase the binary size.
3990 - CONFIG_X86_RESET_VECTOR
3991 If defined, the x86 reset vector code is included. This is not
3992 needed when U-Boot is running from Coreboot.
3995 Defines the MPU clock speed (in MHz).
3997 NOTE : currently only supported on AM335x platforms.
3999 Freescale QE/FMAN Firmware Support:
4000 -----------------------------------
4002 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4003 loading of "firmware", which is encoded in the QE firmware binary format.
4004 This firmware often needs to be loaded during U-Boot booting, so macros
4005 are used to identify the storage device (NOR flash, SPI, etc) and the address
4008 - CONFIG_SYS_QE_FMAN_FW_ADDR
4009 The address in the storage device where the firmware is located. The
4010 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4013 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4014 The maximum possible size of the firmware. The firmware binary format
4015 has a field that specifies the actual size of the firmware, but it
4016 might not be possible to read any part of the firmware unless some
4017 local storage is allocated to hold the entire firmware first.
4019 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4020 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4021 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4022 virtual address in NOR flash.
4024 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4025 Specifies that QE/FMAN firmware is located in NAND flash.
4026 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4028 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4029 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4030 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4032 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4033 Specifies that QE/FMAN firmware is located on the primary SPI
4034 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4036 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4037 Specifies that QE/FMAN firmware is located in the remote (master)
4038 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4039 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4040 window->master inbound window->master LAW->the ucode address in
4041 master's memory space.
4043 Building the Software:
4044 ======================
4046 Building U-Boot has been tested in several native build environments
4047 and in many different cross environments. Of course we cannot support
4048 all possibly existing versions of cross development tools in all
4049 (potentially obsolete) versions. In case of tool chain problems we
4050 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4051 which is extensively used to build and test U-Boot.
4053 If you are not using a native environment, it is assumed that you
4054 have GNU cross compiling tools available in your path. In this case,
4055 you must set the environment variable CROSS_COMPILE in your shell.
4056 Note that no changes to the Makefile or any other source files are
4057 necessary. For example using the ELDK on a 4xx CPU, please enter:
4059 $ CROSS_COMPILE=ppc_4xx-
4060 $ export CROSS_COMPILE
4062 Note: If you wish to generate Windows versions of the utilities in
4063 the tools directory you can use the MinGW toolchain
4064 (http://www.mingw.org). Set your HOST tools to the MinGW
4065 toolchain and execute 'make tools'. For example:
4067 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4069 Binaries such as tools/mkimage.exe will be created which can
4070 be executed on computers running Windows.
4072 U-Boot is intended to be simple to build. After installing the
4073 sources you must configure U-Boot for one specific board type. This
4078 where "NAME_config" is the name of one of the existing configu-
4079 rations; see boards.cfg for supported names.
4081 Note: for some board special configuration names may exist; check if
4082 additional information is available from the board vendor; for
4083 instance, the TQM823L systems are available without (standard)
4084 or with LCD support. You can select such additional "features"
4085 when choosing the configuration, i. e.
4088 - will configure for a plain TQM823L, i. e. no LCD support
4090 make TQM823L_LCD_config
4091 - will configure for a TQM823L with U-Boot console on LCD
4096 Finally, type "make all", and you should get some working U-Boot
4097 images ready for download to / installation on your system:
4099 - "u-boot.bin" is a raw binary image
4100 - "u-boot" is an image in ELF binary format
4101 - "u-boot.srec" is in Motorola S-Record format
4103 By default the build is performed locally and the objects are saved
4104 in the source directory. One of the two methods can be used to change
4105 this behavior and build U-Boot to some external directory:
4107 1. Add O= to the make command line invocations:
4109 make O=/tmp/build distclean
4110 make O=/tmp/build NAME_config
4111 make O=/tmp/build all
4113 2. Set environment variable BUILD_DIR to point to the desired location:
4115 export BUILD_DIR=/tmp/build
4120 Note that the command line "O=" setting overrides the BUILD_DIR environment
4124 Please be aware that the Makefiles assume you are using GNU make, so
4125 for instance on NetBSD you might need to use "gmake" instead of
4129 If the system board that you have is not listed, then you will need
4130 to port U-Boot to your hardware platform. To do this, follow these
4133 1. Add a new configuration option for your board to the toplevel
4134 "boards.cfg" file, using the existing entries as examples.
4135 Follow the instructions there to keep the boards in order.
4136 2. Create a new directory to hold your board specific code. Add any
4137 files you need. In your board directory, you will need at least
4138 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4139 3. Create a new configuration file "include/configs/<board>.h" for
4141 3. If you're porting U-Boot to a new CPU, then also create a new
4142 directory to hold your CPU specific code. Add any files you need.
4143 4. Run "make <board>_config" with your new name.
4144 5. Type "make", and you should get a working "u-boot.srec" file
4145 to be installed on your target system.
4146 6. Debug and solve any problems that might arise.
4147 [Of course, this last step is much harder than it sounds.]
4150 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4151 ==============================================================
4153 If you have modified U-Boot sources (for instance added a new board
4154 or support for new devices, a new CPU, etc.) you are expected to
4155 provide feedback to the other developers. The feedback normally takes
4156 the form of a "patch", i. e. a context diff against a certain (latest
4157 official or latest in the git repository) version of U-Boot sources.
4159 But before you submit such a patch, please verify that your modifi-
4160 cation did not break existing code. At least make sure that *ALL* of
4161 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4162 just run the "MAKEALL" script, which will configure and build U-Boot
4163 for ALL supported system. Be warned, this will take a while. You can
4164 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4165 environment variable to the script, i. e. to use the ELDK cross tools
4168 CROSS_COMPILE=ppc_8xx- MAKEALL
4170 or to build on a native PowerPC system you can type
4172 CROSS_COMPILE=' ' MAKEALL
4174 When using the MAKEALL script, the default behaviour is to build
4175 U-Boot in the source directory. This location can be changed by
4176 setting the BUILD_DIR environment variable. Also, for each target
4177 built, the MAKEALL script saves two log files (<target>.ERR and
4178 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4179 location can be changed by setting the MAKEALL_LOGDIR environment
4180 variable. For example:
4182 export BUILD_DIR=/tmp/build
4183 export MAKEALL_LOGDIR=/tmp/log
4184 CROSS_COMPILE=ppc_8xx- MAKEALL
4186 With the above settings build objects are saved in the /tmp/build,
4187 log files are saved in the /tmp/log and the source tree remains clean
4188 during the whole build process.
4191 See also "U-Boot Porting Guide" below.
4194 Monitor Commands - Overview:
4195 ============================
4197 go - start application at address 'addr'
4198 run - run commands in an environment variable
4199 bootm - boot application image from memory
4200 bootp - boot image via network using BootP/TFTP protocol
4201 bootz - boot zImage from memory
4202 tftpboot- boot image via network using TFTP protocol
4203 and env variables "ipaddr" and "serverip"
4204 (and eventually "gatewayip")
4205 tftpput - upload a file via network using TFTP protocol
4206 rarpboot- boot image via network using RARP/TFTP protocol
4207 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4208 loads - load S-Record file over serial line
4209 loadb - load binary file over serial line (kermit mode)
4211 mm - memory modify (auto-incrementing)
4212 nm - memory modify (constant address)
4213 mw - memory write (fill)
4215 cmp - memory compare
4216 crc32 - checksum calculation
4217 i2c - I2C sub-system
4218 sspi - SPI utility commands
4219 base - print or set address offset
4220 printenv- print environment variables
4221 setenv - set environment variables
4222 saveenv - save environment variables to persistent storage
4223 protect - enable or disable FLASH write protection
4224 erase - erase FLASH memory
4225 flinfo - print FLASH memory information
4226 nand - NAND memory operations (see doc/README.nand)
4227 bdinfo - print Board Info structure
4228 iminfo - print header information for application image
4229 coninfo - print console devices and informations
4230 ide - IDE sub-system
4231 loop - infinite loop on address range
4232 loopw - infinite write loop on address range
4233 mtest - simple RAM test
4234 icache - enable or disable instruction cache
4235 dcache - enable or disable data cache
4236 reset - Perform RESET of the CPU
4237 echo - echo args to console
4238 version - print monitor version
4239 help - print online help
4240 ? - alias for 'help'
4243 Monitor Commands - Detailed Description:
4244 ========================================
4248 For now: just type "help <command>".
4251 Environment Variables:
4252 ======================
4254 U-Boot supports user configuration using Environment Variables which
4255 can be made persistent by saving to Flash memory.
4257 Environment Variables are set using "setenv", printed using
4258 "printenv", and saved to Flash using "saveenv". Using "setenv"
4259 without a value can be used to delete a variable from the
4260 environment. As long as you don't save the environment you are
4261 working with an in-memory copy. In case the Flash area containing the
4262 environment is erased by accident, a default environment is provided.
4264 Some configuration options can be set using Environment Variables.
4266 List of environment variables (most likely not complete):
4268 baudrate - see CONFIG_BAUDRATE
4270 bootdelay - see CONFIG_BOOTDELAY
4272 bootcmd - see CONFIG_BOOTCOMMAND
4274 bootargs - Boot arguments when booting an RTOS image
4276 bootfile - Name of the image to load with TFTP
4278 bootm_low - Memory range available for image processing in the bootm
4279 command can be restricted. This variable is given as
4280 a hexadecimal number and defines lowest address allowed
4281 for use by the bootm command. See also "bootm_size"
4282 environment variable. Address defined by "bootm_low" is
4283 also the base of the initial memory mapping for the Linux
4284 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4287 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4288 This variable is given as a hexadecimal number and it
4289 defines the size of the memory region starting at base
4290 address bootm_low that is accessible by the Linux kernel
4291 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4292 as the default value if it is defined, and bootm_size is
4295 bootm_size - Memory range available for image processing in the bootm
4296 command can be restricted. This variable is given as
4297 a hexadecimal number and defines the size of the region
4298 allowed for use by the bootm command. See also "bootm_low"
4299 environment variable.
4301 updatefile - Location of the software update file on a TFTP server, used
4302 by the automatic software update feature. Please refer to
4303 documentation in doc/README.update for more details.
4305 autoload - if set to "no" (any string beginning with 'n'),
4306 "bootp" will just load perform a lookup of the
4307 configuration from the BOOTP server, but not try to
4308 load any image using TFTP
4310 autostart - if set to "yes", an image loaded using the "bootp",
4311 "rarpboot", "tftpboot" or "diskboot" commands will
4312 be automatically started (by internally calling
4315 If set to "no", a standalone image passed to the
4316 "bootm" command will be copied to the load address
4317 (and eventually uncompressed), but NOT be started.
4318 This can be used to load and uncompress arbitrary
4321 fdt_high - if set this restricts the maximum address that the
4322 flattened device tree will be copied into upon boot.
4323 For example, if you have a system with 1 GB memory
4324 at physical address 0x10000000, while Linux kernel
4325 only recognizes the first 704 MB as low memory, you
4326 may need to set fdt_high as 0x3C000000 to have the
4327 device tree blob be copied to the maximum address
4328 of the 704 MB low memory, so that Linux kernel can
4329 access it during the boot procedure.
4331 If this is set to the special value 0xFFFFFFFF then
4332 the fdt will not be copied at all on boot. For this
4333 to work it must reside in writable memory, have
4334 sufficient padding on the end of it for u-boot to
4335 add the information it needs into it, and the memory
4336 must be accessible by the kernel.
4338 fdtcontroladdr- if set this is the address of the control flattened
4339 device tree used by U-Boot when CONFIG_OF_CONTROL is
4342 i2cfast - (PPC405GP|PPC405EP only)
4343 if set to 'y' configures Linux I2C driver for fast
4344 mode (400kHZ). This environment variable is used in
4345 initialization code. So, for changes to be effective
4346 it must be saved and board must be reset.
4348 initrd_high - restrict positioning of initrd images:
4349 If this variable is not set, initrd images will be
4350 copied to the highest possible address in RAM; this
4351 is usually what you want since it allows for
4352 maximum initrd size. If for some reason you want to
4353 make sure that the initrd image is loaded below the
4354 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4355 variable to a value of "no" or "off" or "0".
4356 Alternatively, you can set it to a maximum upper
4357 address to use (U-Boot will still check that it
4358 does not overwrite the U-Boot stack and data).
4360 For instance, when you have a system with 16 MB
4361 RAM, and want to reserve 4 MB from use by Linux,
4362 you can do this by adding "mem=12M" to the value of
4363 the "bootargs" variable. However, now you must make
4364 sure that the initrd image is placed in the first
4365 12 MB as well - this can be done with
4367 setenv initrd_high 00c00000
4369 If you set initrd_high to 0xFFFFFFFF, this is an
4370 indication to U-Boot that all addresses are legal
4371 for the Linux kernel, including addresses in flash
4372 memory. In this case U-Boot will NOT COPY the
4373 ramdisk at all. This may be useful to reduce the
4374 boot time on your system, but requires that this
4375 feature is supported by your Linux kernel.
4377 ipaddr - IP address; needed for tftpboot command
4379 loadaddr - Default load address for commands like "bootp",
4380 "rarpboot", "tftpboot", "loadb" or "diskboot"
4382 loads_echo - see CONFIG_LOADS_ECHO
4384 serverip - TFTP server IP address; needed for tftpboot command
4386 bootretry - see CONFIG_BOOT_RETRY_TIME
4388 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4390 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4392 ethprime - controls which interface is used first.
4394 ethact - controls which interface is currently active.
4395 For example you can do the following
4397 => setenv ethact FEC
4398 => ping 192.168.0.1 # traffic sent on FEC
4399 => setenv ethact SCC
4400 => ping 10.0.0.1 # traffic sent on SCC
4402 ethrotate - When set to "no" U-Boot does not go through all
4403 available network interfaces.
4404 It just stays at the currently selected interface.
4406 netretry - When set to "no" each network operation will
4407 either succeed or fail without retrying.
4408 When set to "once" the network operation will
4409 fail when all the available network interfaces
4410 are tried once without success.
4411 Useful on scripts which control the retry operation
4414 npe_ucode - set load address for the NPE microcode
4416 tftpsrcport - If this is set, the value is used for TFTP's
4419 tftpdstport - If this is set, the value is used for TFTP's UDP
4420 destination port instead of the Well Know Port 69.
4422 tftpblocksize - Block size to use for TFTP transfers; if not set,
4423 we use the TFTP server's default block size
4425 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4426 seconds, minimum value is 1000 = 1 second). Defines
4427 when a packet is considered to be lost so it has to
4428 be retransmitted. The default is 5000 = 5 seconds.
4429 Lowering this value may make downloads succeed
4430 faster in networks with high packet loss rates or
4431 with unreliable TFTP servers.
4433 vlan - When set to a value < 4095 the traffic over
4434 Ethernet is encapsulated/received over 802.1q
4437 The following image location variables contain the location of images
4438 used in booting. The "Image" column gives the role of the image and is
4439 not an environment variable name. The other columns are environment
4440 variable names. "File Name" gives the name of the file on a TFTP
4441 server, "RAM Address" gives the location in RAM the image will be
4442 loaded to, and "Flash Location" gives the image's address in NOR
4443 flash or offset in NAND flash.
4445 *Note* - these variables don't have to be defined for all boards, some
4446 boards currenlty use other variables for these purposes, and some
4447 boards use these variables for other purposes.
4449 Image File Name RAM Address Flash Location
4450 ----- --------- ----------- --------------
4451 u-boot u-boot u-boot_addr_r u-boot_addr
4452 Linux kernel bootfile kernel_addr_r kernel_addr
4453 device tree blob fdtfile fdt_addr_r fdt_addr
4454 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4456 The following environment variables may be used and automatically
4457 updated by the network boot commands ("bootp" and "rarpboot"),
4458 depending the information provided by your boot server:
4460 bootfile - see above
4461 dnsip - IP address of your Domain Name Server
4462 dnsip2 - IP address of your secondary Domain Name Server
4463 gatewayip - IP address of the Gateway (Router) to use
4464 hostname - Target hostname
4466 netmask - Subnet Mask
4467 rootpath - Pathname of the root filesystem on the NFS server
4468 serverip - see above
4471 There are two special Environment Variables:
4473 serial# - contains hardware identification information such
4474 as type string and/or serial number
4475 ethaddr - Ethernet address
4477 These variables can be set only once (usually during manufacturing of
4478 the board). U-Boot refuses to delete or overwrite these variables
4479 once they have been set once.
4482 Further special Environment Variables:
4484 ver - Contains the U-Boot version string as printed
4485 with the "version" command. This variable is
4486 readonly (see CONFIG_VERSION_VARIABLE).
4489 Please note that changes to some configuration parameters may take
4490 only effect after the next boot (yes, that's just like Windoze :-).
4493 Callback functions for environment variables:
4494 ---------------------------------------------
4496 For some environment variables, the behavior of u-boot needs to change
4497 when their values are changed. This functionailty allows functions to
4498 be associated with arbitrary variables. On creation, overwrite, or
4499 deletion, the callback will provide the opportunity for some side
4500 effect to happen or for the change to be rejected.
4502 The callbacks are named and associated with a function using the
4503 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4505 These callbacks are associated with variables in one of two ways. The
4506 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4507 in the board configuration to a string that defines a list of
4508 associations. The list must be in the following format:
4510 entry = variable_name[:callback_name]
4513 If the callback name is not specified, then the callback is deleted.
4514 Spaces are also allowed anywhere in the list.
4516 Callbacks can also be associated by defining the ".callbacks" variable
4517 with the same list format above. Any association in ".callbacks" will
4518 override any association in the static list. You can define
4519 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4520 ".callbacks" envirnoment variable in the default or embedded environment.
4523 Command Line Parsing:
4524 =====================
4526 There are two different command line parsers available with U-Boot:
4527 the old "simple" one, and the much more powerful "hush" shell:
4529 Old, simple command line parser:
4530 --------------------------------
4532 - supports environment variables (through setenv / saveenv commands)
4533 - several commands on one line, separated by ';'
4534 - variable substitution using "... ${name} ..." syntax
4535 - special characters ('$', ';') can be escaped by prefixing with '\',
4537 setenv bootcmd bootm \${address}
4538 - You can also escape text by enclosing in single apostrophes, for example:
4539 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4544 - similar to Bourne shell, with control structures like
4545 if...then...else...fi, for...do...done; while...do...done,
4546 until...do...done, ...
4547 - supports environment ("global") variables (through setenv / saveenv
4548 commands) and local shell variables (through standard shell syntax
4549 "name=value"); only environment variables can be used with "run"
4555 (1) If a command line (or an environment variable executed by a "run"
4556 command) contains several commands separated by semicolon, and
4557 one of these commands fails, then the remaining commands will be
4560 (2) If you execute several variables with one call to run (i. e.
4561 calling run with a list of variables as arguments), any failing
4562 command will cause "run" to terminate, i. e. the remaining
4563 variables are not executed.
4565 Note for Redundant Ethernet Interfaces:
4566 =======================================
4568 Some boards come with redundant Ethernet interfaces; U-Boot supports
4569 such configurations and is capable of automatic selection of a
4570 "working" interface when needed. MAC assignment works as follows:
4572 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4573 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4574 "eth1addr" (=>eth1), "eth2addr", ...
4576 If the network interface stores some valid MAC address (for instance
4577 in SROM), this is used as default address if there is NO correspon-
4578 ding setting in the environment; if the corresponding environment
4579 variable is set, this overrides the settings in the card; that means:
4581 o If the SROM has a valid MAC address, and there is no address in the
4582 environment, the SROM's address is used.
4584 o If there is no valid address in the SROM, and a definition in the
4585 environment exists, then the value from the environment variable is
4588 o If both the SROM and the environment contain a MAC address, and
4589 both addresses are the same, this MAC address is used.
4591 o If both the SROM and the environment contain a MAC address, and the
4592 addresses differ, the value from the environment is used and a
4595 o If neither SROM nor the environment contain a MAC address, an error
4598 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4599 will be programmed into hardware as part of the initialization process. This
4600 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4601 The naming convention is as follows:
4602 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4607 U-Boot is capable of booting (and performing other auxiliary operations on)
4608 images in two formats:
4610 New uImage format (FIT)
4611 -----------------------
4613 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4614 to Flattened Device Tree). It allows the use of images with multiple
4615 components (several kernels, ramdisks, etc.), with contents protected by
4616 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4622 Old image format is based on binary files which can be basically anything,
4623 preceded by a special header; see the definitions in include/image.h for
4624 details; basically, the header defines the following image properties:
4626 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4627 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4628 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4629 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4631 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4632 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4633 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4634 * Compression Type (uncompressed, gzip, bzip2)
4640 The header is marked by a special Magic Number, and both the header
4641 and the data portions of the image are secured against corruption by
4648 Although U-Boot should support any OS or standalone application
4649 easily, the main focus has always been on Linux during the design of
4652 U-Boot includes many features that so far have been part of some
4653 special "boot loader" code within the Linux kernel. Also, any
4654 "initrd" images to be used are no longer part of one big Linux image;
4655 instead, kernel and "initrd" are separate images. This implementation
4656 serves several purposes:
4658 - the same features can be used for other OS or standalone
4659 applications (for instance: using compressed images to reduce the
4660 Flash memory footprint)
4662 - it becomes much easier to port new Linux kernel versions because
4663 lots of low-level, hardware dependent stuff are done by U-Boot
4665 - the same Linux kernel image can now be used with different "initrd"
4666 images; of course this also means that different kernel images can
4667 be run with the same "initrd". This makes testing easier (you don't
4668 have to build a new "zImage.initrd" Linux image when you just
4669 change a file in your "initrd"). Also, a field-upgrade of the
4670 software is easier now.
4676 Porting Linux to U-Boot based systems:
4677 ---------------------------------------
4679 U-Boot cannot save you from doing all the necessary modifications to
4680 configure the Linux device drivers for use with your target hardware
4681 (no, we don't intend to provide a full virtual machine interface to
4684 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4686 Just make sure your machine specific header file (for instance
4687 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4688 Information structure as we define in include/asm-<arch>/u-boot.h,
4689 and make sure that your definition of IMAP_ADDR uses the same value
4690 as your U-Boot configuration in CONFIG_SYS_IMMR.
4693 Configuring the Linux kernel:
4694 -----------------------------
4696 No specific requirements for U-Boot. Make sure you have some root
4697 device (initial ramdisk, NFS) for your target system.
4700 Building a Linux Image:
4701 -----------------------
4703 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4704 not used. If you use recent kernel source, a new build target
4705 "uImage" will exist which automatically builds an image usable by
4706 U-Boot. Most older kernels also have support for a "pImage" target,
4707 which was introduced for our predecessor project PPCBoot and uses a
4708 100% compatible format.
4717 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4718 encapsulate a compressed Linux kernel image with header information,
4719 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4721 * build a standard "vmlinux" kernel image (in ELF binary format):
4723 * convert the kernel into a raw binary image:
4725 ${CROSS_COMPILE}-objcopy -O binary \
4726 -R .note -R .comment \
4727 -S vmlinux linux.bin
4729 * compress the binary image:
4733 * package compressed binary image for U-Boot:
4735 mkimage -A ppc -O linux -T kernel -C gzip \
4736 -a 0 -e 0 -n "Linux Kernel Image" \
4737 -d linux.bin.gz uImage
4740 The "mkimage" tool can also be used to create ramdisk images for use
4741 with U-Boot, either separated from the Linux kernel image, or
4742 combined into one file. "mkimage" encapsulates the images with a 64
4743 byte header containing information about target architecture,
4744 operating system, image type, compression method, entry points, time
4745 stamp, CRC32 checksums, etc.
4747 "mkimage" can be called in two ways: to verify existing images and
4748 print the header information, or to build new images.
4750 In the first form (with "-l" option) mkimage lists the information
4751 contained in the header of an existing U-Boot image; this includes
4752 checksum verification:
4754 tools/mkimage -l image
4755 -l ==> list image header information
4757 The second form (with "-d" option) is used to build a U-Boot image
4758 from a "data file" which is used as image payload:
4760 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4761 -n name -d data_file image
4762 -A ==> set architecture to 'arch'
4763 -O ==> set operating system to 'os'
4764 -T ==> set image type to 'type'
4765 -C ==> set compression type 'comp'
4766 -a ==> set load address to 'addr' (hex)
4767 -e ==> set entry point to 'ep' (hex)
4768 -n ==> set image name to 'name'
4769 -d ==> use image data from 'datafile'
4771 Right now, all Linux kernels for PowerPC systems use the same load
4772 address (0x00000000), but the entry point address depends on the
4775 - 2.2.x kernels have the entry point at 0x0000000C,
4776 - 2.3.x and later kernels have the entry point at 0x00000000.
4778 So a typical call to build a U-Boot image would read:
4780 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4781 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4782 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4783 > examples/uImage.TQM850L
4784 Image Name: 2.4.4 kernel for TQM850L
4785 Created: Wed Jul 19 02:34:59 2000
4786 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4787 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4788 Load Address: 0x00000000
4789 Entry Point: 0x00000000
4791 To verify the contents of the image (or check for corruption):
4793 -> tools/mkimage -l examples/uImage.TQM850L
4794 Image Name: 2.4.4 kernel for TQM850L
4795 Created: Wed Jul 19 02:34:59 2000
4796 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4797 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4798 Load Address: 0x00000000
4799 Entry Point: 0x00000000
4801 NOTE: for embedded systems where boot time is critical you can trade
4802 speed for memory and install an UNCOMPRESSED image instead: this
4803 needs more space in Flash, but boots much faster since it does not
4804 need to be uncompressed:
4806 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4807 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4808 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4809 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4810 > examples/uImage.TQM850L-uncompressed
4811 Image Name: 2.4.4 kernel for TQM850L
4812 Created: Wed Jul 19 02:34:59 2000
4813 Image Type: PowerPC Linux Kernel Image (uncompressed)
4814 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4815 Load Address: 0x00000000
4816 Entry Point: 0x00000000
4819 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4820 when your kernel is intended to use an initial ramdisk:
4822 -> tools/mkimage -n 'Simple Ramdisk Image' \
4823 > -A ppc -O linux -T ramdisk -C gzip \
4824 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4825 Image Name: Simple Ramdisk Image
4826 Created: Wed Jan 12 14:01:50 2000
4827 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4828 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4829 Load Address: 0x00000000
4830 Entry Point: 0x00000000
4833 Installing a Linux Image:
4834 -------------------------
4836 To downloading a U-Boot image over the serial (console) interface,
4837 you must convert the image to S-Record format:
4839 objcopy -I binary -O srec examples/image examples/image.srec
4841 The 'objcopy' does not understand the information in the U-Boot
4842 image header, so the resulting S-Record file will be relative to
4843 address 0x00000000. To load it to a given address, you need to
4844 specify the target address as 'offset' parameter with the 'loads'
4847 Example: install the image to address 0x40100000 (which on the
4848 TQM8xxL is in the first Flash bank):
4850 => erase 40100000 401FFFFF
4856 ## Ready for S-Record download ...
4857 ~>examples/image.srec
4858 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4860 15989 15990 15991 15992
4861 [file transfer complete]
4863 ## Start Addr = 0x00000000
4866 You can check the success of the download using the 'iminfo' command;
4867 this includes a checksum verification so you can be sure no data
4868 corruption happened:
4872 ## Checking Image at 40100000 ...
4873 Image Name: 2.2.13 for initrd on TQM850L
4874 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4875 Data Size: 335725 Bytes = 327 kB = 0 MB
4876 Load Address: 00000000
4877 Entry Point: 0000000c
4878 Verifying Checksum ... OK
4884 The "bootm" command is used to boot an application that is stored in
4885 memory (RAM or Flash). In case of a Linux kernel image, the contents
4886 of the "bootargs" environment variable is passed to the kernel as
4887 parameters. You can check and modify this variable using the
4888 "printenv" and "setenv" commands:
4891 => printenv bootargs
4892 bootargs=root=/dev/ram
4894 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4896 => printenv bootargs
4897 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4900 ## Booting Linux kernel at 40020000 ...
4901 Image Name: 2.2.13 for NFS on TQM850L
4902 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4903 Data Size: 381681 Bytes = 372 kB = 0 MB
4904 Load Address: 00000000
4905 Entry Point: 0000000c
4906 Verifying Checksum ... OK
4907 Uncompressing Kernel Image ... OK
4908 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
4909 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4910 time_init: decrementer frequency = 187500000/60
4911 Calibrating delay loop... 49.77 BogoMIPS
4912 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4915 If you want to boot a Linux kernel with initial RAM disk, you pass
4916 the memory addresses of both the kernel and the initrd image (PPBCOOT
4917 format!) to the "bootm" command:
4919 => imi 40100000 40200000
4921 ## Checking Image at 40100000 ...
4922 Image Name: 2.2.13 for initrd on TQM850L
4923 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4924 Data Size: 335725 Bytes = 327 kB = 0 MB
4925 Load Address: 00000000
4926 Entry Point: 0000000c
4927 Verifying Checksum ... OK
4929 ## Checking Image at 40200000 ...
4930 Image Name: Simple Ramdisk Image
4931 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4932 Data Size: 566530 Bytes = 553 kB = 0 MB
4933 Load Address: 00000000
4934 Entry Point: 00000000
4935 Verifying Checksum ... OK
4937 => bootm 40100000 40200000
4938 ## Booting Linux kernel at 40100000 ...
4939 Image Name: 2.2.13 for initrd on TQM850L
4940 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4941 Data Size: 335725 Bytes = 327 kB = 0 MB
4942 Load Address: 00000000
4943 Entry Point: 0000000c
4944 Verifying Checksum ... OK
4945 Uncompressing Kernel Image ... OK
4946 ## Loading RAMDisk Image at 40200000 ...
4947 Image Name: Simple Ramdisk Image
4948 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4949 Data Size: 566530 Bytes = 553 kB = 0 MB
4950 Load Address: 00000000
4951 Entry Point: 00000000
4952 Verifying Checksum ... OK
4953 Loading Ramdisk ... OK
4954 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
4955 Boot arguments: root=/dev/ram
4956 time_init: decrementer frequency = 187500000/60
4957 Calibrating delay loop... 49.77 BogoMIPS
4959 RAMDISK: Compressed image found at block 0
4960 VFS: Mounted root (ext2 filesystem).
4964 Boot Linux and pass a flat device tree:
4967 First, U-Boot must be compiled with the appropriate defines. See the section
4968 titled "Linux Kernel Interface" above for a more in depth explanation. The
4969 following is an example of how to start a kernel and pass an updated
4975 oft=oftrees/mpc8540ads.dtb
4976 => tftp $oftaddr $oft
4977 Speed: 1000, full duplex
4979 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4980 Filename 'oftrees/mpc8540ads.dtb'.
4981 Load address: 0x300000
4984 Bytes transferred = 4106 (100a hex)
4985 => tftp $loadaddr $bootfile
4986 Speed: 1000, full duplex
4988 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4990 Load address: 0x200000
4991 Loading:############
4993 Bytes transferred = 1029407 (fb51f hex)
4998 => bootm $loadaddr - $oftaddr
4999 ## Booting image at 00200000 ...
5000 Image Name: Linux-2.6.17-dirty
5001 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5002 Data Size: 1029343 Bytes = 1005.2 kB
5003 Load Address: 00000000
5004 Entry Point: 00000000
5005 Verifying Checksum ... OK
5006 Uncompressing Kernel Image ... OK
5007 Booting using flat device tree at 0x300000
5008 Using MPC85xx ADS machine description
5009 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5013 More About U-Boot Image Types:
5014 ------------------------------
5016 U-Boot supports the following image types:
5018 "Standalone Programs" are directly runnable in the environment
5019 provided by U-Boot; it is expected that (if they behave
5020 well) you can continue to work in U-Boot after return from
5021 the Standalone Program.
5022 "OS Kernel Images" are usually images of some Embedded OS which
5023 will take over control completely. Usually these programs
5024 will install their own set of exception handlers, device
5025 drivers, set up the MMU, etc. - this means, that you cannot
5026 expect to re-enter U-Boot except by resetting the CPU.
5027 "RAMDisk Images" are more or less just data blocks, and their
5028 parameters (address, size) are passed to an OS kernel that is
5030 "Multi-File Images" contain several images, typically an OS
5031 (Linux) kernel image and one or more data images like
5032 RAMDisks. This construct is useful for instance when you want
5033 to boot over the network using BOOTP etc., where the boot
5034 server provides just a single image file, but you want to get
5035 for instance an OS kernel and a RAMDisk image.
5037 "Multi-File Images" start with a list of image sizes, each
5038 image size (in bytes) specified by an "uint32_t" in network
5039 byte order. This list is terminated by an "(uint32_t)0".
5040 Immediately after the terminating 0 follow the images, one by
5041 one, all aligned on "uint32_t" boundaries (size rounded up to
5042 a multiple of 4 bytes).
5044 "Firmware Images" are binary images containing firmware (like
5045 U-Boot or FPGA images) which usually will be programmed to
5048 "Script files" are command sequences that will be executed by
5049 U-Boot's command interpreter; this feature is especially
5050 useful when you configure U-Boot to use a real shell (hush)
5051 as command interpreter.
5053 Booting the Linux zImage:
5054 -------------------------
5056 On some platforms, it's possible to boot Linux zImage. This is done
5057 using the "bootz" command. The syntax of "bootz" command is the same
5058 as the syntax of "bootm" command.
5060 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
5061 kernel with raw initrd images. The syntax is slightly different, the
5062 address of the initrd must be augmented by it's size, in the following
5063 format: "<initrd addres>:<initrd size>".
5069 One of the features of U-Boot is that you can dynamically load and
5070 run "standalone" applications, which can use some resources of
5071 U-Boot like console I/O functions or interrupt services.
5073 Two simple examples are included with the sources:
5078 'examples/hello_world.c' contains a small "Hello World" Demo
5079 application; it is automatically compiled when you build U-Boot.
5080 It's configured to run at address 0x00040004, so you can play with it
5084 ## Ready for S-Record download ...
5085 ~>examples/hello_world.srec
5086 1 2 3 4 5 6 7 8 9 10 11 ...
5087 [file transfer complete]
5089 ## Start Addr = 0x00040004
5091 => go 40004 Hello World! This is a test.
5092 ## Starting application at 0x00040004 ...
5103 Hit any key to exit ...
5105 ## Application terminated, rc = 0x0
5107 Another example, which demonstrates how to register a CPM interrupt
5108 handler with the U-Boot code, can be found in 'examples/timer.c'.
5109 Here, a CPM timer is set up to generate an interrupt every second.
5110 The interrupt service routine is trivial, just printing a '.'
5111 character, but this is just a demo program. The application can be
5112 controlled by the following keys:
5114 ? - print current values og the CPM Timer registers
5115 b - enable interrupts and start timer
5116 e - stop timer and disable interrupts
5117 q - quit application
5120 ## Ready for S-Record download ...
5121 ~>examples/timer.srec
5122 1 2 3 4 5 6 7 8 9 10 11 ...
5123 [file transfer complete]
5125 ## Start Addr = 0x00040004
5128 ## Starting application at 0x00040004 ...
5131 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5134 [q, b, e, ?] Set interval 1000000 us
5137 [q, b, e, ?] ........
5138 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5141 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5144 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5147 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5149 [q, b, e, ?] ...Stopping timer
5151 [q, b, e, ?] ## Application terminated, rc = 0x0
5157 Over time, many people have reported problems when trying to use the
5158 "minicom" terminal emulation program for serial download. I (wd)
5159 consider minicom to be broken, and recommend not to use it. Under
5160 Unix, I recommend to use C-Kermit for general purpose use (and
5161 especially for kermit binary protocol download ("loadb" command), and
5162 use "cu" for S-Record download ("loads" command). See
5163 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5164 for help with kermit.
5167 Nevertheless, if you absolutely want to use it try adding this
5168 configuration to your "File transfer protocols" section:
5170 Name Program Name U/D FullScr IO-Red. Multi
5171 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5172 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5178 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5179 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5181 Building requires a cross environment; it is known to work on
5182 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5183 need gmake since the Makefiles are not compatible with BSD make).
5184 Note that the cross-powerpc package does not install include files;
5185 attempting to build U-Boot will fail because <machine/ansi.h> is
5186 missing. This file has to be installed and patched manually:
5188 # cd /usr/pkg/cross/powerpc-netbsd/include
5190 # ln -s powerpc machine
5191 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5192 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5194 Native builds *don't* work due to incompatibilities between native
5195 and U-Boot include files.
5197 Booting assumes that (the first part of) the image booted is a
5198 stage-2 loader which in turn loads and then invokes the kernel
5199 proper. Loader sources will eventually appear in the NetBSD source
5200 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5201 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5204 Implementation Internals:
5205 =========================
5207 The following is not intended to be a complete description of every
5208 implementation detail. However, it should help to understand the
5209 inner workings of U-Boot and make it easier to port it to custom
5213 Initial Stack, Global Data:
5214 ---------------------------
5216 The implementation of U-Boot is complicated by the fact that U-Boot
5217 starts running out of ROM (flash memory), usually without access to
5218 system RAM (because the memory controller is not initialized yet).
5219 This means that we don't have writable Data or BSS segments, and BSS
5220 is not initialized as zero. To be able to get a C environment working
5221 at all, we have to allocate at least a minimal stack. Implementation
5222 options for this are defined and restricted by the CPU used: Some CPU
5223 models provide on-chip memory (like the IMMR area on MPC8xx and
5224 MPC826x processors), on others (parts of) the data cache can be
5225 locked as (mis-) used as memory, etc.
5227 Chris Hallinan posted a good summary of these issues to the
5228 U-Boot mailing list:
5230 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5231 From: "Chris Hallinan" <clh@net1plus.com>
5232 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5235 Correct me if I'm wrong, folks, but the way I understand it
5236 is this: Using DCACHE as initial RAM for Stack, etc, does not
5237 require any physical RAM backing up the cache. The cleverness
5238 is that the cache is being used as a temporary supply of
5239 necessary storage before the SDRAM controller is setup. It's
5240 beyond the scope of this list to explain the details, but you
5241 can see how this works by studying the cache architecture and
5242 operation in the architecture and processor-specific manuals.
5244 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5245 is another option for the system designer to use as an
5246 initial stack/RAM area prior to SDRAM being available. Either
5247 option should work for you. Using CS 4 should be fine if your
5248 board designers haven't used it for something that would
5249 cause you grief during the initial boot! It is frequently not
5252 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5253 with your processor/board/system design. The default value
5254 you will find in any recent u-boot distribution in
5255 walnut.h should work for you. I'd set it to a value larger
5256 than your SDRAM module. If you have a 64MB SDRAM module, set
5257 it above 400_0000. Just make sure your board has no resources
5258 that are supposed to respond to that address! That code in
5259 start.S has been around a while and should work as is when
5260 you get the config right.
5265 It is essential to remember this, since it has some impact on the C
5266 code for the initialization procedures:
5268 * Initialized global data (data segment) is read-only. Do not attempt
5271 * Do not use any uninitialized global data (or implicitely initialized
5272 as zero data - BSS segment) at all - this is undefined, initiali-
5273 zation is performed later (when relocating to RAM).
5275 * Stack space is very limited. Avoid big data buffers or things like
5278 Having only the stack as writable memory limits means we cannot use
5279 normal global data to share information beween the code. But it
5280 turned out that the implementation of U-Boot can be greatly
5281 simplified by making a global data structure (gd_t) available to all
5282 functions. We could pass a pointer to this data as argument to _all_
5283 functions, but this would bloat the code. Instead we use a feature of
5284 the GCC compiler (Global Register Variables) to share the data: we
5285 place a pointer (gd) to the global data into a register which we
5286 reserve for this purpose.
5288 When choosing a register for such a purpose we are restricted by the
5289 relevant (E)ABI specifications for the current architecture, and by
5290 GCC's implementation.
5292 For PowerPC, the following registers have specific use:
5294 R2: reserved for system use
5295 R3-R4: parameter passing and return values
5296 R5-R10: parameter passing
5297 R13: small data area pointer
5301 (U-Boot also uses R12 as internal GOT pointer. r12
5302 is a volatile register so r12 needs to be reset when
5303 going back and forth between asm and C)
5305 ==> U-Boot will use R2 to hold a pointer to the global data
5307 Note: on PPC, we could use a static initializer (since the
5308 address of the global data structure is known at compile time),
5309 but it turned out that reserving a register results in somewhat
5310 smaller code - although the code savings are not that big (on
5311 average for all boards 752 bytes for the whole U-Boot image,
5312 624 text + 127 data).
5314 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5315 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5317 ==> U-Boot will use P3 to hold a pointer to the global data
5319 On ARM, the following registers are used:
5321 R0: function argument word/integer result
5322 R1-R3: function argument word
5324 R10: stack limit (used only if stack checking if enabled)
5325 R11: argument (frame) pointer
5326 R12: temporary workspace
5329 R15: program counter
5331 ==> U-Boot will use R8 to hold a pointer to the global data
5333 On Nios II, the ABI is documented here:
5334 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5336 ==> U-Boot will use gp to hold a pointer to the global data
5338 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5339 to access small data sections, so gp is free.
5341 On NDS32, the following registers are used:
5343 R0-R1: argument/return
5345 R15: temporary register for assembler
5346 R16: trampoline register
5347 R28: frame pointer (FP)
5348 R29: global pointer (GP)
5349 R30: link register (LP)
5350 R31: stack pointer (SP)
5351 PC: program counter (PC)
5353 ==> U-Boot will use R10 to hold a pointer to the global data
5355 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5356 or current versions of GCC may "optimize" the code too much.
5361 U-Boot runs in system state and uses physical addresses, i.e. the
5362 MMU is not used either for address mapping nor for memory protection.
5364 The available memory is mapped to fixed addresses using the memory
5365 controller. In this process, a contiguous block is formed for each
5366 memory type (Flash, SDRAM, SRAM), even when it consists of several
5367 physical memory banks.
5369 U-Boot is installed in the first 128 kB of the first Flash bank (on
5370 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5371 booting and sizing and initializing DRAM, the code relocates itself
5372 to the upper end of DRAM. Immediately below the U-Boot code some
5373 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5374 configuration setting]. Below that, a structure with global Board
5375 Info data is placed, followed by the stack (growing downward).
5377 Additionally, some exception handler code is copied to the low 8 kB
5378 of DRAM (0x00000000 ... 0x00001FFF).
5380 So a typical memory configuration with 16 MB of DRAM could look like
5383 0x0000 0000 Exception Vector code
5386 0x0000 2000 Free for Application Use
5392 0x00FB FF20 Monitor Stack (Growing downward)
5393 0x00FB FFAC Board Info Data and permanent copy of global data
5394 0x00FC 0000 Malloc Arena
5397 0x00FE 0000 RAM Copy of Monitor Code
5398 ... eventually: LCD or video framebuffer
5399 ... eventually: pRAM (Protected RAM - unchanged by reset)
5400 0x00FF FFFF [End of RAM]
5403 System Initialization:
5404 ----------------------
5406 In the reset configuration, U-Boot starts at the reset entry point
5407 (on most PowerPC systems at address 0x00000100). Because of the reset
5408 configuration for CS0# this is a mirror of the onboard Flash memory.
5409 To be able to re-map memory U-Boot then jumps to its link address.
5410 To be able to implement the initialization code in C, a (small!)
5411 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5412 which provide such a feature like MPC8xx or MPC8260), or in a locked
5413 part of the data cache. After that, U-Boot initializes the CPU core,
5414 the caches and the SIU.
5416 Next, all (potentially) available memory banks are mapped using a
5417 preliminary mapping. For example, we put them on 512 MB boundaries
5418 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5419 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5420 programmed for SDRAM access. Using the temporary configuration, a
5421 simple memory test is run that determines the size of the SDRAM
5424 When there is more than one SDRAM bank, and the banks are of
5425 different size, the largest is mapped first. For equal size, the first
5426 bank (CS2#) is mapped first. The first mapping is always for address
5427 0x00000000, with any additional banks following immediately to create
5428 contiguous memory starting from 0.
5430 Then, the monitor installs itself at the upper end of the SDRAM area
5431 and allocates memory for use by malloc() and for the global Board
5432 Info data; also, the exception vector code is copied to the low RAM
5433 pages, and the final stack is set up.
5435 Only after this relocation will you have a "normal" C environment;
5436 until that you are restricted in several ways, mostly because you are
5437 running from ROM, and because the code will have to be relocated to a
5441 U-Boot Porting Guide:
5442 ----------------------
5444 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5448 int main(int argc, char *argv[])
5450 sighandler_t no_more_time;
5452 signal(SIGALRM, no_more_time);
5453 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5455 if (available_money > available_manpower) {
5456 Pay consultant to port U-Boot;
5460 Download latest U-Boot source;
5462 Subscribe to u-boot mailing list;
5465 email("Hi, I am new to U-Boot, how do I get started?");
5468 Read the README file in the top level directory;
5469 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5470 Read applicable doc/*.README;
5471 Read the source, Luke;
5472 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5475 if (available_money > toLocalCurrency ($2500))
5478 Add a lot of aggravation and time;
5480 if (a similar board exists) { /* hopefully... */
5481 cp -a board/<similar> board/<myboard>
5482 cp include/configs/<similar>.h include/configs/<myboard>.h
5484 Create your own board support subdirectory;
5485 Create your own board include/configs/<myboard>.h file;
5487 Edit new board/<myboard> files
5488 Edit new include/configs/<myboard>.h
5493 Add / modify source code;
5497 email("Hi, I am having problems...");
5499 Send patch file to the U-Boot email list;
5500 if (reasonable critiques)
5501 Incorporate improvements from email list code review;
5503 Defend code as written;
5509 void no_more_time (int sig)
5518 All contributions to U-Boot should conform to the Linux kernel
5519 coding style; see the file "Documentation/CodingStyle" and the script
5520 "scripts/Lindent" in your Linux kernel source directory.
5522 Source files originating from a different project (for example the
5523 MTD subsystem) are generally exempt from these guidelines and are not
5524 reformated to ease subsequent migration to newer versions of those
5527 Please note that U-Boot is implemented in C (and to some small parts in
5528 Assembler); no C++ is used, so please do not use C++ style comments (//)
5531 Please also stick to the following formatting rules:
5532 - remove any trailing white space
5533 - use TAB characters for indentation and vertical alignment, not spaces
5534 - make sure NOT to use DOS '\r\n' line feeds
5535 - do not add more than 2 consecutive empty lines to source files
5536 - do not add trailing empty lines to source files
5538 Submissions which do not conform to the standards may be returned
5539 with a request to reformat the changes.
5545 Since the number of patches for U-Boot is growing, we need to
5546 establish some rules. Submissions which do not conform to these rules
5547 may be rejected, even when they contain important and valuable stuff.
5549 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5551 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5552 see http://lists.denx.de/mailman/listinfo/u-boot
5554 When you send a patch, please include the following information with
5557 * For bug fixes: a description of the bug and how your patch fixes
5558 this bug. Please try to include a way of demonstrating that the
5559 patch actually fixes something.
5561 * For new features: a description of the feature and your
5564 * A CHANGELOG entry as plaintext (separate from the patch)
5566 * For major contributions, your entry to the CREDITS file
5568 * When you add support for a new board, don't forget to add this
5569 board to the MAINTAINERS file, too.
5571 * If your patch adds new configuration options, don't forget to
5572 document these in the README file.
5574 * The patch itself. If you are using git (which is *strongly*
5575 recommended) you can easily generate the patch using the
5576 "git format-patch". If you then use "git send-email" to send it to
5577 the U-Boot mailing list, you will avoid most of the common problems
5578 with some other mail clients.
5580 If you cannot use git, use "diff -purN OLD NEW". If your version of
5581 diff does not support these options, then get the latest version of
5584 The current directory when running this command shall be the parent
5585 directory of the U-Boot source tree (i. e. please make sure that
5586 your patch includes sufficient directory information for the
5589 We prefer patches as plain text. MIME attachments are discouraged,
5590 and compressed attachments must not be used.
5592 * If one logical set of modifications affects or creates several
5593 files, all these changes shall be submitted in a SINGLE patch file.
5595 * Changesets that contain different, unrelated modifications shall be
5596 submitted as SEPARATE patches, one patch per changeset.
5601 * Before sending the patch, run the MAKEALL script on your patched
5602 source tree and make sure that no errors or warnings are reported
5603 for any of the boards.
5605 * Keep your modifications to the necessary minimum: A patch
5606 containing several unrelated changes or arbitrary reformats will be
5607 returned with a request to re-formatting / split it.
5609 * If you modify existing code, make sure that your new code does not
5610 add to the memory footprint of the code ;-) Small is beautiful!
5611 When adding new features, these should compile conditionally only
5612 (using #ifdef), and the resulting code with the new feature
5613 disabled must not need more memory than the old code without your
5616 * Remember that there is a size limit of 100 kB per message on the
5617 u-boot mailing list. Bigger patches will be moderated. If they are
5618 reasonable and not too big, they will be acknowledged. But patches
5619 bigger than the size limit should be avoided.
projects / u-boot / blob