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_SOFTSWITCH * Soft switch setting command for BF60x
902 CONFIG_CMD_SOURCE "source" command Support
903 CONFIG_CMD_SPI * SPI serial bus support
904 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
905 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
906 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
907 CONFIG_CMD_TIMER * access to the system tick timer
908 CONFIG_CMD_USB * USB support
909 CONFIG_CMD_CDP * Cisco Discover Protocol support
910 CONFIG_CMD_MFSL * Microblaze FSL support
913 EXAMPLE: If you want all functions except of network
914 support you can write:
916 #include "config_cmd_all.h"
917 #undef CONFIG_CMD_NET
920 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
922 Note: Don't enable the "icache" and "dcache" commands
923 (configuration option CONFIG_CMD_CACHE) unless you know
924 what you (and your U-Boot users) are doing. Data
925 cache cannot be enabled on systems like the 8xx or
926 8260 (where accesses to the IMMR region must be
927 uncached), and it cannot be disabled on all other
928 systems where we (mis-) use the data cache to hold an
929 initial stack and some data.
932 XXX - this list needs to get updated!
934 - Regular expression support:
936 If this variable is defined, U-Boot is linked against
937 the SLRE (Super Light Regular Expression) library,
938 which adds regex support to some commands, as for
939 example "env grep" and "setexpr".
943 If this variable is defined, U-Boot will use a device tree
944 to configure its devices, instead of relying on statically
945 compiled #defines in the board file. This option is
946 experimental and only available on a few boards. The device
947 tree is available in the global data as gd->fdt_blob.
949 U-Boot needs to get its device tree from somewhere. This can
950 be done using one of the two options below:
953 If this variable is defined, U-Boot will embed a device tree
954 binary in its image. This device tree file should be in the
955 board directory and called <soc>-<board>.dts. The binary file
956 is then picked up in board_init_f() and made available through
957 the global data structure as gd->blob.
960 If this variable is defined, U-Boot will build a device tree
961 binary. It will be called u-boot.dtb. Architecture-specific
962 code will locate it at run-time. Generally this works by:
964 cat u-boot.bin u-boot.dtb >image.bin
966 and in fact, U-Boot does this for you, creating a file called
967 u-boot-dtb.bin which is useful in the common case. You can
968 still use the individual files if you need something more
973 If this variable is defined, it enables watchdog
974 support for the SoC. There must be support in the SoC
975 specific code for a watchdog. For the 8xx and 8260
976 CPUs, the SIU Watchdog feature is enabled in the SYPCR
977 register. When supported for a specific SoC is
978 available, then no further board specific code should
982 When using a watchdog circuitry external to the used
983 SoC, then define this variable and provide board
984 specific code for the "hw_watchdog_reset" function.
987 CONFIG_VERSION_VARIABLE
988 If this variable is defined, an environment variable
989 named "ver" is created by U-Boot showing the U-Boot
990 version as printed by the "version" command.
991 Any change to this variable will be reverted at the
996 When CONFIG_CMD_DATE is selected, the type of the RTC
997 has to be selected, too. Define exactly one of the
1000 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1001 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1002 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1003 CONFIG_RTC_MC146818 - use MC146818 RTC
1004 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1005 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1006 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1007 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1008 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1009 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1010 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1011 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1014 Note that if the RTC uses I2C, then the I2C interface
1015 must also be configured. See I2C Support, below.
1018 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1019 CONFIG_PCA953X_INFO - enable pca953x info command
1021 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1022 chip-ngpio pairs that tell the PCA953X driver the number of
1023 pins supported by a particular chip.
1025 Note that if the GPIO device uses I2C, then the I2C interface
1026 must also be configured. See I2C Support, below.
1028 - Timestamp Support:
1030 When CONFIG_TIMESTAMP is selected, the timestamp
1031 (date and time) of an image is printed by image
1032 commands like bootm or iminfo. This option is
1033 automatically enabled when you select CONFIG_CMD_DATE .
1035 - Partition Labels (disklabels) Supported:
1036 Zero or more of the following:
1037 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1038 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1039 Intel architecture, USB sticks, etc.
1040 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1041 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1042 bootloader. Note 2TB partition limit; see
1044 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1046 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1047 CONFIG_CMD_SCSI) you must configure support for at
1048 least one non-MTD partition type as well.
1051 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1052 board configurations files but used nowhere!
1054 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1055 be performed by calling the function
1056 ide_set_reset(int reset)
1057 which has to be defined in a board specific file
1062 Set this to enable ATAPI support.
1067 Set this to enable support for disks larger than 137GB
1068 Also look at CONFIG_SYS_64BIT_LBA.
1069 Whithout these , LBA48 support uses 32bit variables and will 'only'
1070 support disks up to 2.1TB.
1072 CONFIG_SYS_64BIT_LBA:
1073 When enabled, makes the IDE subsystem use 64bit sector addresses.
1077 At the moment only there is only support for the
1078 SYM53C8XX SCSI controller; define
1079 CONFIG_SCSI_SYM53C8XX to enable it.
1081 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1082 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1083 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1084 maximum numbers of LUNs, SCSI ID's and target
1086 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1088 The environment variable 'scsidevs' is set to the number of
1089 SCSI devices found during the last scan.
1091 - NETWORK Support (PCI):
1093 Support for Intel 8254x/8257x gigabit chips.
1096 Utility code for direct access to the SPI bus on Intel 8257x.
1097 This does not do anything useful unless you set at least one
1098 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1100 CONFIG_E1000_SPI_GENERIC
1101 Allow generic access to the SPI bus on the Intel 8257x, for
1102 example with the "sspi" command.
1105 Management command for E1000 devices. When used on devices
1106 with SPI support you can reprogram the EEPROM from U-Boot.
1108 CONFIG_E1000_FALLBACK_MAC
1109 default MAC for empty EEPROM after production.
1112 Support for Intel 82557/82559/82559ER chips.
1113 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1114 write routine for first time initialisation.
1117 Support for Digital 2114x chips.
1118 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1119 modem chip initialisation (KS8761/QS6611).
1122 Support for National dp83815 chips.
1125 Support for National dp8382[01] gigabit chips.
1127 - NETWORK Support (other):
1129 CONFIG_DRIVER_AT91EMAC
1130 Support for AT91RM9200 EMAC.
1133 Define this to use reduced MII inteface
1135 CONFIG_DRIVER_AT91EMAC_QUIET
1136 If this defined, the driver is quiet.
1137 The driver doen't show link status messages.
1139 CONFIG_CALXEDA_XGMAC
1140 Support for the Calxeda XGMAC device
1143 Support for SMSC's LAN91C96 chips.
1145 CONFIG_LAN91C96_BASE
1146 Define this to hold the physical address
1147 of the LAN91C96's I/O space
1149 CONFIG_LAN91C96_USE_32_BIT
1150 Define this to enable 32 bit addressing
1153 Support for SMSC's LAN91C111 chip
1155 CONFIG_SMC91111_BASE
1156 Define this to hold the physical address
1157 of the device (I/O space)
1159 CONFIG_SMC_USE_32_BIT
1160 Define this if data bus is 32 bits
1162 CONFIG_SMC_USE_IOFUNCS
1163 Define this to use i/o functions instead of macros
1164 (some hardware wont work with macros)
1166 CONFIG_DRIVER_TI_EMAC
1167 Support for davinci emac
1169 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1170 Define this if you have more then 3 PHYs.
1173 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1175 CONFIG_FTGMAC100_EGIGA
1176 Define this to use GE link update with gigabit PHY.
1177 Define this if FTGMAC100 is connected to gigabit PHY.
1178 If your system has 10/100 PHY only, it might not occur
1179 wrong behavior. Because PHY usually return timeout or
1180 useless data when polling gigabit status and gigabit
1181 control registers. This behavior won't affect the
1182 correctnessof 10/100 link speed update.
1185 Support for SMSC's LAN911x and LAN921x chips
1188 Define this to hold the physical address
1189 of the device (I/O space)
1191 CONFIG_SMC911X_32_BIT
1192 Define this if data bus is 32 bits
1194 CONFIG_SMC911X_16_BIT
1195 Define this if data bus is 16 bits. If your processor
1196 automatically converts one 32 bit word to two 16 bit
1197 words you may also try CONFIG_SMC911X_32_BIT.
1200 Support for Renesas on-chip Ethernet controller
1202 CONFIG_SH_ETHER_USE_PORT
1203 Define the number of ports to be used
1205 CONFIG_SH_ETHER_PHY_ADDR
1206 Define the ETH PHY's address
1208 CONFIG_SH_ETHER_CACHE_WRITEBACK
1209 If this option is set, the driver enables cache flush.
1212 CONFIG_GENERIC_LPC_TPM
1213 Support for generic parallel port TPM devices. Only one device
1214 per system is supported at this time.
1216 CONFIG_TPM_TIS_BASE_ADDRESS
1217 Base address where the generic TPM device is mapped
1218 to. Contemporary x86 systems usually map it at
1222 At the moment only the UHCI host controller is
1223 supported (PIP405, MIP405, MPC5200); define
1224 CONFIG_USB_UHCI to enable it.
1225 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1226 and define CONFIG_USB_STORAGE to enable the USB
1229 Supported are USB Keyboards and USB Floppy drives
1231 MPC5200 USB requires additional defines:
1233 for 528 MHz Clock: 0x0001bbbb
1237 for differential drivers: 0x00001000
1238 for single ended drivers: 0x00005000
1239 for differential drivers on PSC3: 0x00000100
1240 for single ended drivers on PSC3: 0x00004100
1241 CONFIG_SYS_USB_EVENT_POLL
1242 May be defined to allow interrupt polling
1243 instead of using asynchronous interrupts
1245 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1246 txfilltuning field in the EHCI controller on reset.
1249 Define the below if you wish to use the USB console.
1250 Once firmware is rebuilt from a serial console issue the
1251 command "setenv stdin usbtty; setenv stdout usbtty" and
1252 attach your USB cable. The Unix command "dmesg" should print
1253 it has found a new device. The environment variable usbtty
1254 can be set to gserial or cdc_acm to enable your device to
1255 appear to a USB host as a Linux gserial device or a
1256 Common Device Class Abstract Control Model serial device.
1257 If you select usbtty = gserial you should be able to enumerate
1259 # modprobe usbserial vendor=0xVendorID product=0xProductID
1260 else if using cdc_acm, simply setting the environment
1261 variable usbtty to be cdc_acm should suffice. The following
1262 might be defined in YourBoardName.h
1265 Define this to build a UDC device
1268 Define this to have a tty type of device available to
1269 talk to the UDC device
1272 Define this to enable the high speed support for usb
1273 device and usbtty. If this feature is enabled, a routine
1274 int is_usbd_high_speed(void)
1275 also needs to be defined by the driver to dynamically poll
1276 whether the enumeration has succeded at high speed or full
1279 CONFIG_SYS_CONSOLE_IS_IN_ENV
1280 Define this if you want stdin, stdout &/or stderr to
1284 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1285 Derive USB clock from external clock "blah"
1286 - CONFIG_SYS_USB_EXTC_CLK 0x02
1288 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1289 Derive USB clock from brgclk
1290 - CONFIG_SYS_USB_BRG_CLK 0x04
1292 If you have a USB-IF assigned VendorID then you may wish to
1293 define your own vendor specific values either in BoardName.h
1294 or directly in usbd_vendor_info.h. If you don't define
1295 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1296 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1297 should pretend to be a Linux device to it's target host.
1299 CONFIG_USBD_MANUFACTURER
1300 Define this string as the name of your company for
1301 - CONFIG_USBD_MANUFACTURER "my company"
1303 CONFIG_USBD_PRODUCT_NAME
1304 Define this string as the name of your product
1305 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1307 CONFIG_USBD_VENDORID
1308 Define this as your assigned Vendor ID from the USB
1309 Implementors Forum. This *must* be a genuine Vendor ID
1310 to avoid polluting the USB namespace.
1311 - CONFIG_USBD_VENDORID 0xFFFF
1313 CONFIG_USBD_PRODUCTID
1314 Define this as the unique Product ID
1316 - CONFIG_USBD_PRODUCTID 0xFFFF
1318 - ULPI Layer Support:
1319 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1320 the generic ULPI layer. The generic layer accesses the ULPI PHY
1321 via the platform viewport, so you need both the genric layer and
1322 the viewport enabled. Currently only Chipidea/ARC based
1323 viewport is supported.
1324 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1325 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1326 If your ULPI phy needs a different reference clock than the
1327 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1328 the appropriate value in Hz.
1331 The MMC controller on the Intel PXA is supported. To
1332 enable this define CONFIG_MMC. The MMC can be
1333 accessed from the boot prompt by mapping the device
1334 to physical memory similar to flash. Command line is
1335 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1336 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1339 Support for Renesas on-chip MMCIF controller
1341 CONFIG_SH_MMCIF_ADDR
1342 Define the base address of MMCIF registers
1345 Define the clock frequency for MMCIF
1347 - USB Device Firmware Update (DFU) class support:
1349 This enables the USB portion of the DFU USB class
1352 This enables the command "dfu" which is used to have
1353 U-Boot create a DFU class device via USB. This command
1354 requires that the "dfu_alt_info" environment variable be
1355 set and define the alt settings to expose to the host.
1358 This enables support for exposing (e)MMC devices via DFU.
1361 This enables support for exposing NAND devices via DFU.
1363 CONFIG_SYS_DFU_MAX_FILE_SIZE
1364 When updating files rather than the raw storage device,
1365 we use a static buffer to copy the file into and then write
1366 the buffer once we've been given the whole file. Define
1367 this to the maximum filesize (in bytes) for the buffer.
1368 Default is 4 MiB if undefined.
1370 - Journaling Flash filesystem support:
1371 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1372 CONFIG_JFFS2_NAND_DEV
1373 Define these for a default partition on a NAND device
1375 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1376 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1377 Define these for a default partition on a NOR device
1379 CONFIG_SYS_JFFS_CUSTOM_PART
1380 Define this to create an own partition. You have to provide a
1381 function struct part_info* jffs2_part_info(int part_num)
1383 If you define only one JFFS2 partition you may also want to
1384 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1385 to disable the command chpart. This is the default when you
1386 have not defined a custom partition
1388 - FAT(File Allocation Table) filesystem write function support:
1391 Define this to enable support for saving memory data as a
1392 file in FAT formatted partition.
1394 This will also enable the command "fatwrite" enabling the
1395 user to write files to FAT.
1397 CBFS (Coreboot Filesystem) support
1400 Define this to enable support for reading from a Coreboot
1401 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1407 Define this to enable standard (PC-Style) keyboard
1411 Standard PC keyboard driver with US (is default) and
1412 GERMAN key layout (switch via environment 'keymap=de') support.
1413 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1414 for cfb_console. Supports cursor blinking.
1419 Define this to enable video support (for output to
1422 CONFIG_VIDEO_CT69000
1424 Enable Chips & Technologies 69000 Video chip
1426 CONFIG_VIDEO_SMI_LYNXEM
1427 Enable Silicon Motion SMI 712/710/810 Video chip. The
1428 video output is selected via environment 'videoout'
1429 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1432 For the CT69000 and SMI_LYNXEM drivers, videomode is
1433 selected via environment 'videomode'. Two different ways
1435 - "videomode=num" 'num' is a standard LiLo mode numbers.
1436 Following standard modes are supported (* is default):
1438 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1439 -------------+---------------------------------------------
1440 8 bits | 0x301* 0x303 0x305 0x161 0x307
1441 15 bits | 0x310 0x313 0x316 0x162 0x319
1442 16 bits | 0x311 0x314 0x317 0x163 0x31A
1443 24 bits | 0x312 0x315 0x318 ? 0x31B
1444 -------------+---------------------------------------------
1445 (i.e. setenv videomode 317; saveenv; reset;)
1447 - "videomode=bootargs" all the video parameters are parsed
1448 from the bootargs. (See drivers/video/videomodes.c)
1451 CONFIG_VIDEO_SED13806
1452 Enable Epson SED13806 driver. This driver supports 8bpp
1453 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1454 or CONFIG_VIDEO_SED13806_16BPP
1457 Enable the Freescale DIU video driver. Reference boards for
1458 SOCs that have a DIU should define this macro to enable DIU
1459 support, and should also define these other macros:
1465 CONFIG_VIDEO_SW_CURSOR
1466 CONFIG_VGA_AS_SINGLE_DEVICE
1468 CONFIG_VIDEO_BMP_LOGO
1470 The DIU driver will look for the 'video-mode' environment
1471 variable, and if defined, enable the DIU as a console during
1472 boot. See the documentation file README.video for a
1473 description of this variable.
1477 Enable the VGA video / BIOS for x86. The alternative if you
1478 are using coreboot is to use the coreboot frame buffer
1485 Define this to enable a custom keyboard support.
1486 This simply calls drv_keyboard_init() which must be
1487 defined in your board-specific files.
1488 The only board using this so far is RBC823.
1490 - LCD Support: CONFIG_LCD
1492 Define this to enable LCD support (for output to LCD
1493 display); also select one of the supported displays
1494 by defining one of these:
1498 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1500 CONFIG_NEC_NL6448AC33:
1502 NEC NL6448AC33-18. Active, color, single scan.
1504 CONFIG_NEC_NL6448BC20
1506 NEC NL6448BC20-08. 6.5", 640x480.
1507 Active, color, single scan.
1509 CONFIG_NEC_NL6448BC33_54
1511 NEC NL6448BC33-54. 10.4", 640x480.
1512 Active, color, single scan.
1516 Sharp 320x240. Active, color, single scan.
1517 It isn't 16x9, and I am not sure what it is.
1519 CONFIG_SHARP_LQ64D341
1521 Sharp LQ64D341 display, 640x480.
1522 Active, color, single scan.
1526 HLD1045 display, 640x480.
1527 Active, color, single scan.
1531 Optrex CBL50840-2 NF-FW 99 22 M5
1533 Hitachi LMG6912RPFC-00T
1537 320x240. Black & white.
1539 Normally display is black on white background; define
1540 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1542 CONFIG_LCD_ALIGNMENT
1544 Normally the LCD is page-aligned (tyically 4KB). If this is
1545 defined then the LCD will be aligned to this value instead.
1546 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1547 here, since it is cheaper to change data cache settings on
1548 a per-section basis.
1550 CONFIG_CONSOLE_SCROLL_LINES
1552 When the console need to be scrolled, this is the number of
1553 lines to scroll by. It defaults to 1. Increasing this makes
1554 the console jump but can help speed up operation when scrolling
1559 Support drawing of RLE8-compressed bitmaps on the LCD.
1563 Enables an 'i2c edid' command which can read EDID
1564 information over I2C from an attached LCD display.
1566 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1568 If this option is set, the environment is checked for
1569 a variable "splashimage". If found, the usual display
1570 of logo, copyright and system information on the LCD
1571 is suppressed and the BMP image at the address
1572 specified in "splashimage" is loaded instead. The
1573 console is redirected to the "nulldev", too. This
1574 allows for a "silent" boot where a splash screen is
1575 loaded very quickly after power-on.
1577 CONFIG_SPLASHIMAGE_GUARD
1579 If this option is set, then U-Boot will prevent the environment
1580 variable "splashimage" from being set to a problematic address
1581 (see README.displaying-bmps and README.arm-unaligned-accesses).
1582 This option is useful for targets where, due to alignment
1583 restrictions, an improperly aligned BMP image will cause a data
1584 abort. If you think you will not have problems with unaligned
1585 accesses (for example because your toolchain prevents them)
1586 there is no need to set this option.
1588 CONFIG_SPLASH_SCREEN_ALIGN
1590 If this option is set the splash image can be freely positioned
1591 on the screen. Environment variable "splashpos" specifies the
1592 position as "x,y". If a positive number is given it is used as
1593 number of pixel from left/top. If a negative number is given it
1594 is used as number of pixel from right/bottom. You can also
1595 specify 'm' for centering the image.
1598 setenv splashpos m,m
1599 => image at center of screen
1601 setenv splashpos 30,20
1602 => image at x = 30 and y = 20
1604 setenv splashpos -10,m
1605 => vertically centered image
1606 at x = dspWidth - bmpWidth - 9
1608 CONFIG_SPLASH_SCREEN_PREPARE
1610 If this option is set then the board_splash_screen_prepare()
1611 function, which must be defined in your code, is called as part
1612 of the splash screen display sequence. It gives the board an
1613 opportunity to prepare the splash image data before it is
1614 processed and sent to the frame buffer by U-Boot.
1616 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1618 If this option is set, additionally to standard BMP
1619 images, gzipped BMP images can be displayed via the
1620 splashscreen support or the bmp command.
1622 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1624 If this option is set, 8-bit RLE compressed BMP images
1625 can be displayed via the splashscreen support or the
1628 - Do compresssing for memory range:
1631 If this option is set, it would use zlib deflate method
1632 to compress the specified memory at its best effort.
1634 - Compression support:
1637 If this option is set, support for bzip2 compressed
1638 images is included. If not, only uncompressed and gzip
1639 compressed images are supported.
1641 NOTE: the bzip2 algorithm requires a lot of RAM, so
1642 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1647 If this option is set, support for lzma compressed
1650 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1651 requires an amount of dynamic memory that is given by the
1654 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1656 Where lc and lp stand for, respectively, Literal context bits
1657 and Literal pos bits.
1659 This value is upper-bounded by 14MB in the worst case. Anyway,
1660 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1661 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1662 a very small buffer.
1664 Use the lzmainfo tool to determinate the lc and lp values and
1665 then calculate the amount of needed dynamic memory (ensuring
1666 the appropriate CONFIG_SYS_MALLOC_LEN value).
1671 The address of PHY on MII bus.
1673 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1675 The clock frequency of the MII bus
1679 If this option is set, support for speed/duplex
1680 detection of gigabit PHY is included.
1682 CONFIG_PHY_RESET_DELAY
1684 Some PHY like Intel LXT971A need extra delay after
1685 reset before any MII register access is possible.
1686 For such PHY, set this option to the usec delay
1687 required. (minimum 300usec for LXT971A)
1689 CONFIG_PHY_CMD_DELAY (ppc4xx)
1691 Some PHY like Intel LXT971A need extra delay after
1692 command issued before MII status register can be read
1702 Define a default value for Ethernet address to use
1703 for the respective Ethernet interface, in case this
1704 is not determined automatically.
1709 Define a default value for the IP address to use for
1710 the default Ethernet interface, in case this is not
1711 determined through e.g. bootp.
1712 (Environment variable "ipaddr")
1714 - Server IP address:
1717 Defines a default value for the IP address of a TFTP
1718 server to contact when using the "tftboot" command.
1719 (Environment variable "serverip")
1721 CONFIG_KEEP_SERVERADDR
1723 Keeps the server's MAC address, in the env 'serveraddr'
1724 for passing to bootargs (like Linux's netconsole option)
1726 - Gateway IP address:
1729 Defines a default value for the IP address of the
1730 default router where packets to other networks are
1732 (Environment variable "gatewayip")
1737 Defines a default value for the subnet mask (or
1738 routing prefix) which is used to determine if an IP
1739 address belongs to the local subnet or needs to be
1740 forwarded through a router.
1741 (Environment variable "netmask")
1743 - Multicast TFTP Mode:
1746 Defines whether you want to support multicast TFTP as per
1747 rfc-2090; for example to work with atftp. Lets lots of targets
1748 tftp down the same boot image concurrently. Note: the Ethernet
1749 driver in use must provide a function: mcast() to join/leave a
1752 - BOOTP Recovery Mode:
1753 CONFIG_BOOTP_RANDOM_DELAY
1755 If you have many targets in a network that try to
1756 boot using BOOTP, you may want to avoid that all
1757 systems send out BOOTP requests at precisely the same
1758 moment (which would happen for instance at recovery
1759 from a power failure, when all systems will try to
1760 boot, thus flooding the BOOTP server. Defining
1761 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1762 inserted before sending out BOOTP requests. The
1763 following delays are inserted then:
1765 1st BOOTP request: delay 0 ... 1 sec
1766 2nd BOOTP request: delay 0 ... 2 sec
1767 3rd BOOTP request: delay 0 ... 4 sec
1769 BOOTP requests: delay 0 ... 8 sec
1771 - DHCP Advanced Options:
1772 You can fine tune the DHCP functionality by defining
1773 CONFIG_BOOTP_* symbols:
1775 CONFIG_BOOTP_SUBNETMASK
1776 CONFIG_BOOTP_GATEWAY
1777 CONFIG_BOOTP_HOSTNAME
1778 CONFIG_BOOTP_NISDOMAIN
1779 CONFIG_BOOTP_BOOTPATH
1780 CONFIG_BOOTP_BOOTFILESIZE
1783 CONFIG_BOOTP_SEND_HOSTNAME
1784 CONFIG_BOOTP_NTPSERVER
1785 CONFIG_BOOTP_TIMEOFFSET
1786 CONFIG_BOOTP_VENDOREX
1787 CONFIG_BOOTP_MAY_FAIL
1789 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1790 environment variable, not the BOOTP server.
1792 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1793 after the configured retry count, the call will fail
1794 instead of starting over. This can be used to fail over
1795 to Link-local IP address configuration if the DHCP server
1798 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1799 serverip from a DHCP server, it is possible that more
1800 than one DNS serverip is offered to the client.
1801 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1802 serverip will be stored in the additional environment
1803 variable "dnsip2". The first DNS serverip is always
1804 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1807 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1808 to do a dynamic update of a DNS server. To do this, they
1809 need the hostname of the DHCP requester.
1810 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1811 of the "hostname" environment variable is passed as
1812 option 12 to the DHCP server.
1814 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1816 A 32bit value in microseconds for a delay between
1817 receiving a "DHCP Offer" and sending the "DHCP Request".
1818 This fixes a problem with certain DHCP servers that don't
1819 respond 100% of the time to a "DHCP request". E.g. On an
1820 AT91RM9200 processor running at 180MHz, this delay needed
1821 to be *at least* 15,000 usec before a Windows Server 2003
1822 DHCP server would reply 100% of the time. I recommend at
1823 least 50,000 usec to be safe. The alternative is to hope
1824 that one of the retries will be successful but note that
1825 the DHCP timeout and retry process takes a longer than
1828 - Link-local IP address negotiation:
1829 Negotiate with other link-local clients on the local network
1830 for an address that doesn't require explicit configuration.
1831 This is especially useful if a DHCP server cannot be guaranteed
1832 to exist in all environments that the device must operate.
1834 See doc/README.link-local for more information.
1837 CONFIG_CDP_DEVICE_ID
1839 The device id used in CDP trigger frames.
1841 CONFIG_CDP_DEVICE_ID_PREFIX
1843 A two character string which is prefixed to the MAC address
1848 A printf format string which contains the ascii name of
1849 the port. Normally is set to "eth%d" which sets
1850 eth0 for the first Ethernet, eth1 for the second etc.
1852 CONFIG_CDP_CAPABILITIES
1854 A 32bit integer which indicates the device capabilities;
1855 0x00000010 for a normal host which does not forwards.
1859 An ascii string containing the version of the software.
1863 An ascii string containing the name of the platform.
1867 A 32bit integer sent on the trigger.
1869 CONFIG_CDP_POWER_CONSUMPTION
1871 A 16bit integer containing the power consumption of the
1872 device in .1 of milliwatts.
1874 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1876 A byte containing the id of the VLAN.
1878 - Status LED: CONFIG_STATUS_LED
1880 Several configurations allow to display the current
1881 status using a LED. For instance, the LED will blink
1882 fast while running U-Boot code, stop blinking as
1883 soon as a reply to a BOOTP request was received, and
1884 start blinking slow once the Linux kernel is running
1885 (supported by a status LED driver in the Linux
1886 kernel). Defining CONFIG_STATUS_LED enables this
1889 - CAN Support: CONFIG_CAN_DRIVER
1891 Defining CONFIG_CAN_DRIVER enables CAN driver support
1892 on those systems that support this (optional)
1893 feature, like the TQM8xxL modules.
1895 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1897 These enable I2C serial bus commands. Defining either of
1898 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1899 include the appropriate I2C driver for the selected CPU.
1901 This will allow you to use i2c commands at the u-boot
1902 command line (as long as you set CONFIG_CMD_I2C in
1903 CONFIG_COMMANDS) and communicate with i2c based realtime
1904 clock chips. See common/cmd_i2c.c for a description of the
1905 command line interface.
1907 CONFIG_HARD_I2C selects a hardware I2C controller.
1909 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1910 bit-banging) driver instead of CPM or similar hardware
1913 There are several other quantities that must also be
1914 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1916 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1917 to be the frequency (in Hz) at which you wish your i2c bus
1918 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1919 the CPU's i2c node address).
1921 Now, the u-boot i2c code for the mpc8xx
1922 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1923 and so its address should therefore be cleared to 0 (See,
1924 eg, MPC823e User's Manual p.16-473). So, set
1925 CONFIG_SYS_I2C_SLAVE to 0.
1927 CONFIG_SYS_I2C_INIT_MPC5XXX
1929 When a board is reset during an i2c bus transfer
1930 chips might think that the current transfer is still
1931 in progress. Reset the slave devices by sending start
1932 commands until the slave device responds.
1934 That's all that's required for CONFIG_HARD_I2C.
1936 If you use the software i2c interface (CONFIG_SOFT_I2C)
1937 then the following macros need to be defined (examples are
1938 from include/configs/lwmon.h):
1942 (Optional). Any commands necessary to enable the I2C
1943 controller or configure ports.
1945 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1949 (Only for MPC8260 CPU). The I/O port to use (the code
1950 assumes both bits are on the same port). Valid values
1951 are 0..3 for ports A..D.
1955 The code necessary to make the I2C data line active
1956 (driven). If the data line is open collector, this
1959 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1963 The code necessary to make the I2C data line tri-stated
1964 (inactive). If the data line is open collector, this
1967 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1971 Code that returns true if the I2C data line is high,
1974 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1978 If <bit> is true, sets the I2C data line high. If it
1979 is false, it clears it (low).
1981 eg: #define I2C_SDA(bit) \
1982 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1983 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1987 If <bit> is true, sets the I2C clock line high. If it
1988 is false, it clears it (low).
1990 eg: #define I2C_SCL(bit) \
1991 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1992 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1996 This delay is invoked four times per clock cycle so this
1997 controls the rate of data transfer. The data rate thus
1998 is 1 / (I2C_DELAY * 4). Often defined to be something
2001 #define I2C_DELAY udelay(2)
2003 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2005 If your arch supports the generic GPIO framework (asm/gpio.h),
2006 then you may alternatively define the two GPIOs that are to be
2007 used as SCL / SDA. Any of the previous I2C_xxx macros will
2008 have GPIO-based defaults assigned to them as appropriate.
2010 You should define these to the GPIO value as given directly to
2011 the generic GPIO functions.
2013 CONFIG_SYS_I2C_INIT_BOARD
2015 When a board is reset during an i2c bus transfer
2016 chips might think that the current transfer is still
2017 in progress. On some boards it is possible to access
2018 the i2c SCLK line directly, either by using the
2019 processor pin as a GPIO or by having a second pin
2020 connected to the bus. If this option is defined a
2021 custom i2c_init_board() routine in boards/xxx/board.c
2022 is run early in the boot sequence.
2024 CONFIG_SYS_I2C_BOARD_LATE_INIT
2026 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2027 defined a custom i2c_board_late_init() routine in
2028 boards/xxx/board.c is run AFTER the operations in i2c_init()
2029 is completed. This callpoint can be used to unreset i2c bus
2030 using CPU i2c controller register accesses for CPUs whose i2c
2031 controller provide such a method. It is called at the end of
2032 i2c_init() to allow i2c_init operations to setup the i2c bus
2033 controller on the CPU (e.g. setting bus speed & slave address).
2035 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2037 This option enables configuration of bi_iic_fast[] flags
2038 in u-boot bd_info structure based on u-boot environment
2039 variable "i2cfast". (see also i2cfast)
2041 CONFIG_I2C_MULTI_BUS
2043 This option allows the use of multiple I2C buses, each of which
2044 must have a controller. At any point in time, only one bus is
2045 active. To switch to a different bus, use the 'i2c dev' command.
2046 Note that bus numbering is zero-based.
2048 CONFIG_SYS_I2C_NOPROBES
2050 This option specifies a list of I2C devices that will be skipped
2051 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2052 is set, specify a list of bus-device pairs. Otherwise, specify
2053 a 1D array of device addresses
2056 #undef CONFIG_I2C_MULTI_BUS
2057 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2059 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2061 #define CONFIG_I2C_MULTI_BUS
2062 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2064 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2066 CONFIG_SYS_SPD_BUS_NUM
2068 If defined, then this indicates the I2C bus number for DDR SPD.
2069 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2071 CONFIG_SYS_RTC_BUS_NUM
2073 If defined, then this indicates the I2C bus number for the RTC.
2074 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2076 CONFIG_SYS_DTT_BUS_NUM
2078 If defined, then this indicates the I2C bus number for the DTT.
2079 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2081 CONFIG_SYS_I2C_DTT_ADDR:
2083 If defined, specifies the I2C address of the DTT device.
2084 If not defined, then U-Boot uses predefined value for
2085 specified DTT device.
2089 Define this option if you want to use Freescale's I2C driver in
2090 drivers/i2c/fsl_i2c.c.
2094 Define this option if you have I2C devices reached over 1 .. n
2095 I2C Muxes like the pca9544a. This option addes a new I2C
2096 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2097 new I2C Bus to the existing I2C Busses. If you select the
2098 new Bus with "i2c dev", u-bbot sends first the commandos for
2099 the muxes to activate this new "bus".
2101 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2105 Adding a new I2C Bus reached over 2 pca9544a muxes
2106 The First mux with address 70 and channel 6
2107 The Second mux with address 71 and channel 4
2109 => i2c bus pca9544a:70:6:pca9544a:71:4
2111 Use the "i2c bus" command without parameter, to get a list
2112 of I2C Busses with muxes:
2115 Busses reached over muxes:
2117 reached over Mux(es):
2120 reached over Mux(es):
2125 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2126 u-boot first sends the command to the mux@70 to enable
2127 channel 6, and then the command to the mux@71 to enable
2130 After that, you can use the "normal" i2c commands as
2131 usual to communicate with your I2C devices behind
2134 This option is actually implemented for the bitbanging
2135 algorithm in common/soft_i2c.c and for the Hardware I2C
2136 Bus on the MPC8260. But it should be not so difficult
2137 to add this option to other architectures.
2139 CONFIG_SOFT_I2C_READ_REPEATED_START
2141 defining this will force the i2c_read() function in
2142 the soft_i2c driver to perform an I2C repeated start
2143 between writing the address pointer and reading the
2144 data. If this define is omitted the default behaviour
2145 of doing a stop-start sequence will be used. Most I2C
2146 devices can use either method, but some require one or
2149 - SPI Support: CONFIG_SPI
2151 Enables SPI driver (so far only tested with
2152 SPI EEPROM, also an instance works with Crystal A/D and
2153 D/As on the SACSng board)
2157 Enables the driver for SPI controller on SuperH. Currently
2158 only SH7757 is supported.
2162 Enables extended (16-bit) SPI EEPROM addressing.
2163 (symmetrical to CONFIG_I2C_X)
2167 Enables a software (bit-bang) SPI driver rather than
2168 using hardware support. This is a general purpose
2169 driver that only requires three general I/O port pins
2170 (two outputs, one input) to function. If this is
2171 defined, the board configuration must define several
2172 SPI configuration items (port pins to use, etc). For
2173 an example, see include/configs/sacsng.h.
2177 Enables a hardware SPI driver for general-purpose reads
2178 and writes. As with CONFIG_SOFT_SPI, the board configuration
2179 must define a list of chip-select function pointers.
2180 Currently supported on some MPC8xxx processors. For an
2181 example, see include/configs/mpc8349emds.h.
2185 Enables the driver for the SPI controllers on i.MX and MXC
2186 SoCs. Currently i.MX31/35/51 are supported.
2188 - FPGA Support: CONFIG_FPGA
2190 Enables FPGA subsystem.
2192 CONFIG_FPGA_<vendor>
2194 Enables support for specific chip vendors.
2197 CONFIG_FPGA_<family>
2199 Enables support for FPGA family.
2200 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2204 Specify the number of FPGA devices to support.
2206 CONFIG_SYS_FPGA_PROG_FEEDBACK
2208 Enable printing of hash marks during FPGA configuration.
2210 CONFIG_SYS_FPGA_CHECK_BUSY
2212 Enable checks on FPGA configuration interface busy
2213 status by the configuration function. This option
2214 will require a board or device specific function to
2219 If defined, a function that provides delays in the FPGA
2220 configuration driver.
2222 CONFIG_SYS_FPGA_CHECK_CTRLC
2223 Allow Control-C to interrupt FPGA configuration
2225 CONFIG_SYS_FPGA_CHECK_ERROR
2227 Check for configuration errors during FPGA bitfile
2228 loading. For example, abort during Virtex II
2229 configuration if the INIT_B line goes low (which
2230 indicated a CRC error).
2232 CONFIG_SYS_FPGA_WAIT_INIT
2234 Maximum time to wait for the INIT_B line to deassert
2235 after PROB_B has been deasserted during a Virtex II
2236 FPGA configuration sequence. The default time is 500
2239 CONFIG_SYS_FPGA_WAIT_BUSY
2241 Maximum time to wait for BUSY to deassert during
2242 Virtex II FPGA configuration. The default is 5 ms.
2244 CONFIG_SYS_FPGA_WAIT_CONFIG
2246 Time to wait after FPGA configuration. The default is
2249 - Configuration Management:
2252 If defined, this string will be added to the U-Boot
2253 version information (U_BOOT_VERSION)
2255 - Vendor Parameter Protection:
2257 U-Boot considers the values of the environment
2258 variables "serial#" (Board Serial Number) and
2259 "ethaddr" (Ethernet Address) to be parameters that
2260 are set once by the board vendor / manufacturer, and
2261 protects these variables from casual modification by
2262 the user. Once set, these variables are read-only,
2263 and write or delete attempts are rejected. You can
2264 change this behaviour:
2266 If CONFIG_ENV_OVERWRITE is #defined in your config
2267 file, the write protection for vendor parameters is
2268 completely disabled. Anybody can change or delete
2271 Alternatively, if you #define _both_ CONFIG_ETHADDR
2272 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2273 Ethernet address is installed in the environment,
2274 which can be changed exactly ONCE by the user. [The
2275 serial# is unaffected by this, i. e. it remains
2278 The same can be accomplished in a more flexible way
2279 for any variable by configuring the type of access
2280 to allow for those variables in the ".flags" variable
2281 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2286 Define this variable to enable the reservation of
2287 "protected RAM", i. e. RAM which is not overwritten
2288 by U-Boot. Define CONFIG_PRAM to hold the number of
2289 kB you want to reserve for pRAM. You can overwrite
2290 this default value by defining an environment
2291 variable "pram" to the number of kB you want to
2292 reserve. Note that the board info structure will
2293 still show the full amount of RAM. If pRAM is
2294 reserved, a new environment variable "mem" will
2295 automatically be defined to hold the amount of
2296 remaining RAM in a form that can be passed as boot
2297 argument to Linux, for instance like that:
2299 setenv bootargs ... mem=\${mem}
2302 This way you can tell Linux not to use this memory,
2303 either, which results in a memory region that will
2304 not be affected by reboots.
2306 *WARNING* If your board configuration uses automatic
2307 detection of the RAM size, you must make sure that
2308 this memory test is non-destructive. So far, the
2309 following board configurations are known to be
2312 IVMS8, IVML24, SPD8xx, TQM8xxL,
2313 HERMES, IP860, RPXlite, LWMON,
2316 - Access to physical memory region (> 4GB)
2317 Some basic support is provided for operations on memory not
2318 normally accessible to U-Boot - e.g. some architectures
2319 support access to more than 4GB of memory on 32-bit
2320 machines using physical address extension or similar.
2321 Define CONFIG_PHYSMEM to access this basic support, which
2322 currently only supports clearing the memory.
2327 Define this variable to stop the system in case of a
2328 fatal error, so that you have to reset it manually.
2329 This is probably NOT a good idea for an embedded
2330 system where you want the system to reboot
2331 automatically as fast as possible, but it may be
2332 useful during development since you can try to debug
2333 the conditions that lead to the situation.
2335 CONFIG_NET_RETRY_COUNT
2337 This variable defines the number of retries for
2338 network operations like ARP, RARP, TFTP, or BOOTP
2339 before giving up the operation. If not defined, a
2340 default value of 5 is used.
2344 Timeout waiting for an ARP reply in milliseconds.
2348 Timeout in milliseconds used in NFS protocol.
2349 If you encounter "ERROR: Cannot umount" in nfs command,
2350 try longer timeout such as
2351 #define CONFIG_NFS_TIMEOUT 10000UL
2353 - Command Interpreter:
2354 CONFIG_AUTO_COMPLETE
2356 Enable auto completion of commands using TAB.
2358 Note that this feature has NOT been implemented yet
2359 for the "hush" shell.
2362 CONFIG_SYS_HUSH_PARSER
2364 Define this variable to enable the "hush" shell (from
2365 Busybox) as command line interpreter, thus enabling
2366 powerful command line syntax like
2367 if...then...else...fi conditionals or `&&' and '||'
2368 constructs ("shell scripts").
2370 If undefined, you get the old, much simpler behaviour
2371 with a somewhat smaller memory footprint.
2374 CONFIG_SYS_PROMPT_HUSH_PS2
2376 This defines the secondary prompt string, which is
2377 printed when the command interpreter needs more input
2378 to complete a command. Usually "> ".
2382 In the current implementation, the local variables
2383 space and global environment variables space are
2384 separated. Local variables are those you define by
2385 simply typing `name=value'. To access a local
2386 variable later on, you have write `$name' or
2387 `${name}'; to execute the contents of a variable
2388 directly type `$name' at the command prompt.
2390 Global environment variables are those you use
2391 setenv/printenv to work with. To run a command stored
2392 in such a variable, you need to use the run command,
2393 and you must not use the '$' sign to access them.
2395 To store commands and special characters in a
2396 variable, please use double quotation marks
2397 surrounding the whole text of the variable, instead
2398 of the backslashes before semicolons and special
2401 - Commandline Editing and History:
2402 CONFIG_CMDLINE_EDITING
2404 Enable editing and History functions for interactive
2405 commandline input operations
2407 - Default Environment:
2408 CONFIG_EXTRA_ENV_SETTINGS
2410 Define this to contain any number of null terminated
2411 strings (variable = value pairs) that will be part of
2412 the default environment compiled into the boot image.
2414 For example, place something like this in your
2415 board's config file:
2417 #define CONFIG_EXTRA_ENV_SETTINGS \
2421 Warning: This method is based on knowledge about the
2422 internal format how the environment is stored by the
2423 U-Boot code. This is NOT an official, exported
2424 interface! Although it is unlikely that this format
2425 will change soon, there is no guarantee either.
2426 You better know what you are doing here.
2428 Note: overly (ab)use of the default environment is
2429 discouraged. Make sure to check other ways to preset
2430 the environment like the "source" command or the
2433 CONFIG_ENV_VARS_UBOOT_CONFIG
2435 Define this in order to add variables describing the
2436 U-Boot build configuration to the default environment.
2437 These will be named arch, cpu, board, vendor, and soc.
2439 Enabling this option will cause the following to be defined:
2447 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2449 Define this in order to add variables describing certain
2450 run-time determined information about the hardware to the
2451 environment. These will be named board_name, board_rev.
2453 CONFIG_DELAY_ENVIRONMENT
2455 Normally the environment is loaded when the board is
2456 intialised so that it is available to U-Boot. This inhibits
2457 that so that the environment is not available until
2458 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2459 this is instead controlled by the value of
2460 /config/load-environment.
2462 - DataFlash Support:
2463 CONFIG_HAS_DATAFLASH
2465 Defining this option enables DataFlash features and
2466 allows to read/write in Dataflash via the standard
2469 - Serial Flash support
2472 Defining this option enables SPI flash commands
2473 'sf probe/read/write/erase/update'.
2475 Usage requires an initial 'probe' to define the serial
2476 flash parameters, followed by read/write/erase/update
2479 The following defaults may be provided by the platform
2480 to handle the common case when only a single serial
2481 flash is present on the system.
2483 CONFIG_SF_DEFAULT_BUS Bus identifier
2484 CONFIG_SF_DEFAULT_CS Chip-select
2485 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2486 CONFIG_SF_DEFAULT_SPEED in Hz
2490 Define this option to include a destructive SPI flash
2493 - SystemACE Support:
2496 Adding this option adds support for Xilinx SystemACE
2497 chips attached via some sort of local bus. The address
2498 of the chip must also be defined in the
2499 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2501 #define CONFIG_SYSTEMACE
2502 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2504 When SystemACE support is added, the "ace" device type
2505 becomes available to the fat commands, i.e. fatls.
2507 - TFTP Fixed UDP Port:
2510 If this is defined, the environment variable tftpsrcp
2511 is used to supply the TFTP UDP source port value.
2512 If tftpsrcp isn't defined, the normal pseudo-random port
2513 number generator is used.
2515 Also, the environment variable tftpdstp is used to supply
2516 the TFTP UDP destination port value. If tftpdstp isn't
2517 defined, the normal port 69 is used.
2519 The purpose for tftpsrcp is to allow a TFTP server to
2520 blindly start the TFTP transfer using the pre-configured
2521 target IP address and UDP port. This has the effect of
2522 "punching through" the (Windows XP) firewall, allowing
2523 the remainder of the TFTP transfer to proceed normally.
2524 A better solution is to properly configure the firewall,
2525 but sometimes that is not allowed.
2530 This enables a generic 'hash' command which can produce
2531 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2535 Enable the hash verify command (hash -v). This adds to code
2538 CONFIG_SHA1 - support SHA1 hashing
2539 CONFIG_SHA256 - support SHA256 hashing
2541 Note: There is also a sha1sum command, which should perhaps
2542 be deprecated in favour of 'hash sha1'.
2544 - Show boot progress:
2545 CONFIG_SHOW_BOOT_PROGRESS
2547 Defining this option allows to add some board-
2548 specific code (calling a user-provided function
2549 "show_boot_progress(int)") that enables you to show
2550 the system's boot progress on some display (for
2551 example, some LED's) on your board. At the moment,
2552 the following checkpoints are implemented:
2554 - Detailed boot stage timing
2556 Define this option to get detailed timing of each stage
2557 of the boot process.
2559 CONFIG_BOOTSTAGE_USER_COUNT
2560 This is the number of available user bootstage records.
2561 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2562 a new ID will be allocated from this stash. If you exceed
2563 the limit, recording will stop.
2565 CONFIG_BOOTSTAGE_REPORT
2566 Define this to print a report before boot, similar to this:
2568 Timer summary in microseconds:
2571 3,575,678 3,575,678 board_init_f start
2572 3,575,695 17 arch_cpu_init A9
2573 3,575,777 82 arch_cpu_init done
2574 3,659,598 83,821 board_init_r start
2575 3,910,375 250,777 main_loop
2576 29,916,167 26,005,792 bootm_start
2577 30,361,327 445,160 start_kernel
2579 CONFIG_CMD_BOOTSTAGE
2580 Add a 'bootstage' command which supports printing a report
2581 and un/stashing of bootstage data.
2583 CONFIG_BOOTSTAGE_FDT
2584 Stash the bootstage information in the FDT. A root 'bootstage'
2585 node is created with each bootstage id as a child. Each child
2586 has a 'name' property and either 'mark' containing the
2587 mark time in microsecond, or 'accum' containing the
2588 accumulated time for that bootstage id in microseconds.
2593 name = "board_init_f";
2602 Code in the Linux kernel can find this in /proc/devicetree.
2604 Legacy uImage format:
2607 1 common/cmd_bootm.c before attempting to boot an image
2608 -1 common/cmd_bootm.c Image header has bad magic number
2609 2 common/cmd_bootm.c Image header has correct magic number
2610 -2 common/cmd_bootm.c Image header has bad checksum
2611 3 common/cmd_bootm.c Image header has correct checksum
2612 -3 common/cmd_bootm.c Image data has bad checksum
2613 4 common/cmd_bootm.c Image data has correct checksum
2614 -4 common/cmd_bootm.c Image is for unsupported architecture
2615 5 common/cmd_bootm.c Architecture check OK
2616 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2617 6 common/cmd_bootm.c Image Type check OK
2618 -6 common/cmd_bootm.c gunzip uncompression error
2619 -7 common/cmd_bootm.c Unimplemented compression type
2620 7 common/cmd_bootm.c Uncompression OK
2621 8 common/cmd_bootm.c No uncompress/copy overwrite error
2622 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2624 9 common/image.c Start initial ramdisk verification
2625 -10 common/image.c Ramdisk header has bad magic number
2626 -11 common/image.c Ramdisk header has bad checksum
2627 10 common/image.c Ramdisk header is OK
2628 -12 common/image.c Ramdisk data has bad checksum
2629 11 common/image.c Ramdisk data has correct checksum
2630 12 common/image.c Ramdisk verification complete, start loading
2631 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2632 13 common/image.c Start multifile image verification
2633 14 common/image.c No initial ramdisk, no multifile, continue.
2635 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2637 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2638 -31 post/post.c POST test failed, detected by post_output_backlog()
2639 -32 post/post.c POST test failed, detected by post_run_single()
2641 34 common/cmd_doc.c before loading a Image from a DOC device
2642 -35 common/cmd_doc.c Bad usage of "doc" command
2643 35 common/cmd_doc.c correct usage of "doc" command
2644 -36 common/cmd_doc.c No boot device
2645 36 common/cmd_doc.c correct boot device
2646 -37 common/cmd_doc.c Unknown Chip ID on boot device
2647 37 common/cmd_doc.c correct chip ID found, device available
2648 -38 common/cmd_doc.c Read Error on boot device
2649 38 common/cmd_doc.c reading Image header from DOC device OK
2650 -39 common/cmd_doc.c Image header has bad magic number
2651 39 common/cmd_doc.c Image header has correct magic number
2652 -40 common/cmd_doc.c Error reading Image from DOC device
2653 40 common/cmd_doc.c Image header has correct magic number
2654 41 common/cmd_ide.c before loading a Image from a IDE device
2655 -42 common/cmd_ide.c Bad usage of "ide" command
2656 42 common/cmd_ide.c correct usage of "ide" command
2657 -43 common/cmd_ide.c No boot device
2658 43 common/cmd_ide.c boot device found
2659 -44 common/cmd_ide.c Device not available
2660 44 common/cmd_ide.c Device available
2661 -45 common/cmd_ide.c wrong partition selected
2662 45 common/cmd_ide.c partition selected
2663 -46 common/cmd_ide.c Unknown partition table
2664 46 common/cmd_ide.c valid partition table found
2665 -47 common/cmd_ide.c Invalid partition type
2666 47 common/cmd_ide.c correct partition type
2667 -48 common/cmd_ide.c Error reading Image Header on boot device
2668 48 common/cmd_ide.c reading Image Header from IDE device OK
2669 -49 common/cmd_ide.c Image header has bad magic number
2670 49 common/cmd_ide.c Image header has correct magic number
2671 -50 common/cmd_ide.c Image header has bad checksum
2672 50 common/cmd_ide.c Image header has correct checksum
2673 -51 common/cmd_ide.c Error reading Image from IDE device
2674 51 common/cmd_ide.c reading Image from IDE device OK
2675 52 common/cmd_nand.c before loading a Image from a NAND device
2676 -53 common/cmd_nand.c Bad usage of "nand" command
2677 53 common/cmd_nand.c correct usage of "nand" command
2678 -54 common/cmd_nand.c No boot device
2679 54 common/cmd_nand.c boot device found
2680 -55 common/cmd_nand.c Unknown Chip ID on boot device
2681 55 common/cmd_nand.c correct chip ID found, device available
2682 -56 common/cmd_nand.c Error reading Image Header on boot device
2683 56 common/cmd_nand.c reading Image Header from NAND device OK
2684 -57 common/cmd_nand.c Image header has bad magic number
2685 57 common/cmd_nand.c Image header has correct magic number
2686 -58 common/cmd_nand.c Error reading Image from NAND device
2687 58 common/cmd_nand.c reading Image from NAND device OK
2689 -60 common/env_common.c Environment has a bad CRC, using default
2691 64 net/eth.c starting with Ethernet configuration.
2692 -64 net/eth.c no Ethernet found.
2693 65 net/eth.c Ethernet found.
2695 -80 common/cmd_net.c usage wrong
2696 80 common/cmd_net.c before calling NetLoop()
2697 -81 common/cmd_net.c some error in NetLoop() occurred
2698 81 common/cmd_net.c NetLoop() back without error
2699 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2700 82 common/cmd_net.c trying automatic boot
2701 83 common/cmd_net.c running "source" command
2702 -83 common/cmd_net.c some error in automatic boot or "source" command
2703 84 common/cmd_net.c end without errors
2708 100 common/cmd_bootm.c Kernel FIT Image has correct format
2709 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2710 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2711 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2712 102 common/cmd_bootm.c Kernel unit name specified
2713 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2714 103 common/cmd_bootm.c Found configuration node
2715 104 common/cmd_bootm.c Got kernel subimage node offset
2716 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2717 105 common/cmd_bootm.c Kernel subimage hash verification OK
2718 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2719 106 common/cmd_bootm.c Architecture check OK
2720 -106 common/cmd_bootm.c Kernel subimage has wrong type
2721 107 common/cmd_bootm.c Kernel subimage type OK
2722 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2723 108 common/cmd_bootm.c Got kernel subimage data/size
2724 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2725 -109 common/cmd_bootm.c Can't get kernel subimage type
2726 -110 common/cmd_bootm.c Can't get kernel subimage comp
2727 -111 common/cmd_bootm.c Can't get kernel subimage os
2728 -112 common/cmd_bootm.c Can't get kernel subimage load address
2729 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2731 120 common/image.c Start initial ramdisk verification
2732 -120 common/image.c Ramdisk FIT image has incorrect format
2733 121 common/image.c Ramdisk FIT image has correct format
2734 122 common/image.c No ramdisk subimage unit name, using configuration
2735 -122 common/image.c Can't get configuration for ramdisk subimage
2736 123 common/image.c Ramdisk unit name specified
2737 -124 common/image.c Can't get ramdisk subimage node offset
2738 125 common/image.c Got ramdisk subimage node offset
2739 -125 common/image.c Ramdisk subimage hash verification failed
2740 126 common/image.c Ramdisk subimage hash verification OK
2741 -126 common/image.c Ramdisk subimage for unsupported architecture
2742 127 common/image.c Architecture check OK
2743 -127 common/image.c Can't get ramdisk subimage data/size
2744 128 common/image.c Got ramdisk subimage data/size
2745 129 common/image.c Can't get ramdisk load address
2746 -129 common/image.c Got ramdisk load address
2748 -130 common/cmd_doc.c Incorrect FIT image format
2749 131 common/cmd_doc.c FIT image format OK
2751 -140 common/cmd_ide.c Incorrect FIT image format
2752 141 common/cmd_ide.c FIT image format OK
2754 -150 common/cmd_nand.c Incorrect FIT image format
2755 151 common/cmd_nand.c FIT image format OK
2757 - FIT image support:
2759 Enable support for the FIT uImage format.
2761 CONFIG_FIT_BEST_MATCH
2762 When no configuration is explicitly selected, default to the
2763 one whose fdt's compatibility field best matches that of
2764 U-Boot itself. A match is considered "best" if it matches the
2765 most specific compatibility entry of U-Boot's fdt's root node.
2766 The order of entries in the configuration's fdt is ignored.
2768 - Standalone program support:
2769 CONFIG_STANDALONE_LOAD_ADDR
2771 This option defines a board specific value for the
2772 address where standalone program gets loaded, thus
2773 overwriting the architecture dependent default
2776 - Frame Buffer Address:
2779 Define CONFIG_FB_ADDR if you want to use specific
2780 address for frame buffer. This is typically the case
2781 when using a graphics controller has separate video
2782 memory. U-Boot will then place the frame buffer at
2783 the given address instead of dynamically reserving it
2784 in system RAM by calling lcd_setmem(), which grabs
2785 the memory for the frame buffer depending on the
2786 configured panel size.
2788 Please see board_init_f function.
2790 - Automatic software updates via TFTP server
2792 CONFIG_UPDATE_TFTP_CNT_MAX
2793 CONFIG_UPDATE_TFTP_MSEC_MAX
2795 These options enable and control the auto-update feature;
2796 for a more detailed description refer to doc/README.update.
2798 - MTD Support (mtdparts command, UBI support)
2801 Adds the MTD device infrastructure from the Linux kernel.
2802 Needed for mtdparts command support.
2804 CONFIG_MTD_PARTITIONS
2806 Adds the MTD partitioning infrastructure from the Linux
2807 kernel. Needed for UBI support.
2812 Adds commands for interacting with MTD partitions formatted
2813 with the UBI flash translation layer
2815 Requires also defining CONFIG_RBTREE
2817 CONFIG_UBI_SILENCE_MSG
2819 Make the verbose messages from UBI stop printing. This leaves
2820 warnings and errors enabled.
2825 Adds commands for interacting with UBI volumes formatted as
2826 UBIFS. UBIFS is read-only in u-boot.
2828 Requires UBI support as well as CONFIG_LZO
2830 CONFIG_UBIFS_SILENCE_MSG
2832 Make the verbose messages from UBIFS stop printing. This leaves
2833 warnings and errors enabled.
2837 Enable building of SPL globally.
2840 LDSCRIPT for linking the SPL binary.
2842 CONFIG_SPL_MAX_FOOTPRINT
2843 Maximum size in memory allocated to the SPL, BSS included.
2844 When defined, the linker checks that the actual memory
2845 used by SPL from _start to __bss_end does not exceed it.
2846 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2847 must not be both defined at the same time.
2850 Maximum size of the SPL image (text, data, rodata, and
2851 linker lists sections), BSS excluded.
2852 When defined, the linker checks that the actual size does
2855 CONFIG_SPL_TEXT_BASE
2856 TEXT_BASE for linking the SPL binary.
2858 CONFIG_SPL_RELOC_TEXT_BASE
2859 Address to relocate to. If unspecified, this is equal to
2860 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2862 CONFIG_SPL_BSS_START_ADDR
2863 Link address for the BSS within the SPL binary.
2865 CONFIG_SPL_BSS_MAX_SIZE
2866 Maximum size in memory allocated to the SPL BSS.
2867 When defined, the linker checks that the actual memory used
2868 by SPL from __bss_start to __bss_end does not exceed it.
2869 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2870 must not be both defined at the same time.
2873 Adress of the start of the stack SPL will use
2875 CONFIG_SPL_RELOC_STACK
2876 Adress of the start of the stack SPL will use after
2877 relocation. If unspecified, this is equal to
2880 CONFIG_SYS_SPL_MALLOC_START
2881 Starting address of the malloc pool used in SPL.
2883 CONFIG_SYS_SPL_MALLOC_SIZE
2884 The size of the malloc pool used in SPL.
2886 CONFIG_SPL_FRAMEWORK
2887 Enable the SPL framework under common/. This framework
2888 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2889 NAND loading of the Linux Kernel.
2891 CONFIG_SPL_DISPLAY_PRINT
2892 For ARM, enable an optional function to print more information
2893 about the running system.
2895 CONFIG_SPL_INIT_MINIMAL
2896 Arch init code should be built for a very small image
2898 CONFIG_SPL_LIBCOMMON_SUPPORT
2899 Support for common/libcommon.o in SPL binary
2901 CONFIG_SPL_LIBDISK_SUPPORT
2902 Support for disk/libdisk.o in SPL binary
2904 CONFIG_SPL_I2C_SUPPORT
2905 Support for drivers/i2c/libi2c.o in SPL binary
2907 CONFIG_SPL_GPIO_SUPPORT
2908 Support for drivers/gpio/libgpio.o in SPL binary
2910 CONFIG_SPL_MMC_SUPPORT
2911 Support for drivers/mmc/libmmc.o in SPL binary
2913 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2914 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2915 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2916 Address, size and partition on the MMC to load U-Boot from
2917 when the MMC is being used in raw mode.
2919 CONFIG_SPL_FAT_SUPPORT
2920 Support for fs/fat/libfat.o in SPL binary
2922 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2923 Filename to read to load U-Boot when reading from FAT
2925 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2926 Set this for NAND SPL on PPC mpc83xx targets, so that
2927 start.S waits for the rest of the SPL to load before
2928 continuing (the hardware starts execution after just
2929 loading the first page rather than the full 4K).
2931 CONFIG_SPL_NAND_BASE
2932 Include nand_base.c in the SPL. Requires
2933 CONFIG_SPL_NAND_DRIVERS.
2935 CONFIG_SPL_NAND_DRIVERS
2936 SPL uses normal NAND drivers, not minimal drivers.
2939 Include standard software ECC in the SPL
2941 CONFIG_SPL_NAND_SIMPLE
2942 Support for NAND boot using simple NAND drivers that
2943 expose the cmd_ctrl() interface.
2945 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2946 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2947 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2948 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2949 CONFIG_SYS_NAND_ECCBYTES
2950 Defines the size and behavior of the NAND that SPL uses
2953 CONFIG_SYS_NAND_U_BOOT_OFFS
2954 Location in NAND to read U-Boot from
2956 CONFIG_SYS_NAND_U_BOOT_DST
2957 Location in memory to load U-Boot to
2959 CONFIG_SYS_NAND_U_BOOT_SIZE
2960 Size of image to load
2962 CONFIG_SYS_NAND_U_BOOT_START
2963 Entry point in loaded image to jump to
2965 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2966 Define this if you need to first read the OOB and then the
2967 data. This is used for example on davinci plattforms.
2969 CONFIG_SPL_OMAP3_ID_NAND
2970 Support for an OMAP3-specific set of functions to return the
2971 ID and MFR of the first attached NAND chip, if present.
2973 CONFIG_SPL_SERIAL_SUPPORT
2974 Support for drivers/serial/libserial.o in SPL binary
2976 CONFIG_SPL_SPI_FLASH_SUPPORT
2977 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2979 CONFIG_SPL_SPI_SUPPORT
2980 Support for drivers/spi/libspi.o in SPL binary
2982 CONFIG_SPL_RAM_DEVICE
2983 Support for running image already present in ram, in SPL binary
2985 CONFIG_SPL_LIBGENERIC_SUPPORT
2986 Support for lib/libgeneric.o in SPL binary
2989 Image offset to which the SPL should be padded before appending
2990 the SPL payload. By default, this is defined as
2991 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2992 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2993 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2996 Final target image containing SPL and payload. Some SPLs
2997 use an arch-specific makefile fragment instead, for
2998 example if more than one image needs to be produced.
3003 [so far only for SMDK2400 boards]
3005 - Modem support enable:
3006 CONFIG_MODEM_SUPPORT
3008 - RTS/CTS Flow control enable:
3011 - Modem debug support:
3012 CONFIG_MODEM_SUPPORT_DEBUG
3014 Enables debugging stuff (char screen[1024], dbg())
3015 for modem support. Useful only with BDI2000.
3017 - Interrupt support (PPC):
3019 There are common interrupt_init() and timer_interrupt()
3020 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3021 for CPU specific initialization. interrupt_init_cpu()
3022 should set decrementer_count to appropriate value. If
3023 CPU resets decrementer automatically after interrupt
3024 (ppc4xx) it should set decrementer_count to zero.
3025 timer_interrupt() calls timer_interrupt_cpu() for CPU
3026 specific handling. If board has watchdog / status_led
3027 / other_activity_monitor it works automatically from
3028 general timer_interrupt().
3032 In the target system modem support is enabled when a
3033 specific key (key combination) is pressed during
3034 power-on. Otherwise U-Boot will boot normally
3035 (autoboot). The key_pressed() function is called from
3036 board_init(). Currently key_pressed() is a dummy
3037 function, returning 1 and thus enabling modem
3040 If there are no modem init strings in the
3041 environment, U-Boot proceed to autoboot; the
3042 previous output (banner, info printfs) will be
3045 See also: doc/README.Modem
3047 Board initialization settings:
3048 ------------------------------
3050 During Initialization u-boot calls a number of board specific functions
3051 to allow the preparation of board specific prerequisites, e.g. pin setup
3052 before drivers are initialized. To enable these callbacks the
3053 following configuration macros have to be defined. Currently this is
3054 architecture specific, so please check arch/your_architecture/lib/board.c
3055 typically in board_init_f() and board_init_r().
3057 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3058 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3059 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3060 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3062 Configuration Settings:
3063 -----------------------
3065 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3066 undefine this when you're short of memory.
3068 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3069 width of the commands listed in the 'help' command output.
3071 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3072 prompt for user input.
3074 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3076 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3078 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3080 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3081 the application (usually a Linux kernel) when it is
3084 - CONFIG_SYS_BAUDRATE_TABLE:
3085 List of legal baudrate settings for this board.
3087 - CONFIG_SYS_CONSOLE_INFO_QUIET
3088 Suppress display of console information at boot.
3090 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3091 If the board specific function
3092 extern int overwrite_console (void);
3093 returns 1, the stdin, stderr and stdout are switched to the
3094 serial port, else the settings in the environment are used.
3096 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3097 Enable the call to overwrite_console().
3099 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3100 Enable overwrite of previous console environment settings.
3102 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3103 Begin and End addresses of the area used by the
3106 - CONFIG_SYS_ALT_MEMTEST:
3107 Enable an alternate, more extensive memory test.
3109 - CONFIG_SYS_MEMTEST_SCRATCH:
3110 Scratch address used by the alternate memory test
3111 You only need to set this if address zero isn't writeable
3113 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3114 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3115 this specified memory area will get subtracted from the top
3116 (end) of RAM and won't get "touched" at all by U-Boot. By
3117 fixing up gd->ram_size the Linux kernel should gets passed
3118 the now "corrected" memory size and won't touch it either.
3119 This should work for arch/ppc and arch/powerpc. Only Linux
3120 board ports in arch/powerpc with bootwrapper support that
3121 recalculate the memory size from the SDRAM controller setup
3122 will have to get fixed in Linux additionally.
3124 This option can be used as a workaround for the 440EPx/GRx
3125 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3128 WARNING: Please make sure that this value is a multiple of
3129 the Linux page size (normally 4k). If this is not the case,
3130 then the end address of the Linux memory will be located at a
3131 non page size aligned address and this could cause major
3134 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3135 Enable temporary baudrate change while serial download
3137 - CONFIG_SYS_SDRAM_BASE:
3138 Physical start address of SDRAM. _Must_ be 0 here.
3140 - CONFIG_SYS_MBIO_BASE:
3141 Physical start address of Motherboard I/O (if using a
3144 - CONFIG_SYS_FLASH_BASE:
3145 Physical start address of Flash memory.
3147 - CONFIG_SYS_MONITOR_BASE:
3148 Physical start address of boot monitor code (set by
3149 make config files to be same as the text base address
3150 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3151 CONFIG_SYS_FLASH_BASE when booting from flash.
3153 - CONFIG_SYS_MONITOR_LEN:
3154 Size of memory reserved for monitor code, used to
3155 determine _at_compile_time_ (!) if the environment is
3156 embedded within the U-Boot image, or in a separate
3159 - CONFIG_SYS_MALLOC_LEN:
3160 Size of DRAM reserved for malloc() use.
3162 - CONFIG_SYS_BOOTM_LEN:
3163 Normally compressed uImages are limited to an
3164 uncompressed size of 8 MBytes. If this is not enough,
3165 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3166 to adjust this setting to your needs.
3168 - CONFIG_SYS_BOOTMAPSZ:
3169 Maximum size of memory mapped by the startup code of
3170 the Linux kernel; all data that must be processed by
3171 the Linux kernel (bd_info, boot arguments, FDT blob if
3172 used) must be put below this limit, unless "bootm_low"
3173 enviroment variable is defined and non-zero. In such case
3174 all data for the Linux kernel must be between "bootm_low"
3175 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3176 variable "bootm_mapsize" will override the value of
3177 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3178 then the value in "bootm_size" will be used instead.
3180 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3181 Enable initrd_high functionality. If defined then the
3182 initrd_high feature is enabled and the bootm ramdisk subcommand
3185 - CONFIG_SYS_BOOT_GET_CMDLINE:
3186 Enables allocating and saving kernel cmdline in space between
3187 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3189 - CONFIG_SYS_BOOT_GET_KBD:
3190 Enables allocating and saving a kernel copy of the bd_info in
3191 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3193 - CONFIG_SYS_MAX_FLASH_BANKS:
3194 Max number of Flash memory banks
3196 - CONFIG_SYS_MAX_FLASH_SECT:
3197 Max number of sectors on a Flash chip
3199 - CONFIG_SYS_FLASH_ERASE_TOUT:
3200 Timeout for Flash erase operations (in ms)
3202 - CONFIG_SYS_FLASH_WRITE_TOUT:
3203 Timeout for Flash write operations (in ms)
3205 - CONFIG_SYS_FLASH_LOCK_TOUT
3206 Timeout for Flash set sector lock bit operation (in ms)
3208 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3209 Timeout for Flash clear lock bits operation (in ms)
3211 - CONFIG_SYS_FLASH_PROTECTION
3212 If defined, hardware flash sectors protection is used
3213 instead of U-Boot software protection.
3215 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3217 Enable TFTP transfers directly to flash memory;
3218 without this option such a download has to be
3219 performed in two steps: (1) download to RAM, and (2)
3220 copy from RAM to flash.
3222 The two-step approach is usually more reliable, since
3223 you can check if the download worked before you erase
3224 the flash, but in some situations (when system RAM is
3225 too limited to allow for a temporary copy of the
3226 downloaded image) this option may be very useful.
3228 - CONFIG_SYS_FLASH_CFI:
3229 Define if the flash driver uses extra elements in the
3230 common flash structure for storing flash geometry.
3232 - CONFIG_FLASH_CFI_DRIVER
3233 This option also enables the building of the cfi_flash driver
3234 in the drivers directory
3236 - CONFIG_FLASH_CFI_MTD
3237 This option enables the building of the cfi_mtd driver
3238 in the drivers directory. The driver exports CFI flash
3241 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3242 Use buffered writes to flash.
3244 - CONFIG_FLASH_SPANSION_S29WS_N
3245 s29ws-n MirrorBit flash has non-standard addresses for buffered
3248 - CONFIG_SYS_FLASH_QUIET_TEST
3249 If this option is defined, the common CFI flash doesn't
3250 print it's warning upon not recognized FLASH banks. This
3251 is useful, if some of the configured banks are only
3252 optionally available.
3254 - CONFIG_FLASH_SHOW_PROGRESS
3255 If defined (must be an integer), print out countdown
3256 digits and dots. Recommended value: 45 (9..1) for 80
3257 column displays, 15 (3..1) for 40 column displays.
3259 - CONFIG_FLASH_VERIFY
3260 If defined, the content of the flash (destination) is compared
3261 against the source after the write operation. An error message
3262 will be printed when the contents are not identical.
3263 Please note that this option is useless in nearly all cases,
3264 since such flash programming errors usually are detected earlier
3265 while unprotecting/erasing/programming. Please only enable
3266 this option if you really know what you are doing.
3268 - CONFIG_SYS_RX_ETH_BUFFER:
3269 Defines the number of Ethernet receive buffers. On some
3270 Ethernet controllers it is recommended to set this value
3271 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3272 buffers can be full shortly after enabling the interface
3273 on high Ethernet traffic.
3274 Defaults to 4 if not defined.
3276 - CONFIG_ENV_MAX_ENTRIES
3278 Maximum number of entries in the hash table that is used
3279 internally to store the environment settings. The default
3280 setting is supposed to be generous and should work in most
3281 cases. This setting can be used to tune behaviour; see
3282 lib/hashtable.c for details.
3284 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3285 - CONFIG_ENV_FLAGS_LIST_STATIC
3286 Enable validation of the values given to enviroment variables when
3287 calling env set. Variables can be restricted to only decimal,
3288 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3289 the variables can also be restricted to IP address or MAC address.
3291 The format of the list is:
3292 type_attribute = [s|d|x|b|i|m]
3293 access_atribute = [a|r|o|c]
3294 attributes = type_attribute[access_atribute]
3295 entry = variable_name[:attributes]
3298 The type attributes are:
3299 s - String (default)
3302 b - Boolean ([1yYtT|0nNfF])
3306 The access attributes are:
3312 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3313 Define this to a list (string) to define the ".flags"
3314 envirnoment variable in the default or embedded environment.
3316 - CONFIG_ENV_FLAGS_LIST_STATIC
3317 Define this to a list (string) to define validation that
3318 should be done if an entry is not found in the ".flags"
3319 environment variable. To override a setting in the static
3320 list, simply add an entry for the same variable name to the
3323 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3324 If defined, don't allow the -f switch to env set override variable
3327 - CONFIG_SYS_GENERIC_BOARD
3328 This selects the architecture-generic board system instead of the
3329 architecture-specific board files. It is intended to move boards
3330 to this new framework over time. Defining this will disable the
3331 arch/foo/lib/board.c file and use common/board_f.c and
3332 common/board_r.c instead. To use this option your architecture
3333 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3334 its config.mk file). If you find problems enabling this option on
3335 your board please report the problem and send patches!
3337 - CONFIG_SYS_SYM_OFFSETS
3338 This is set by architectures that use offsets for link symbols
3339 instead of absolute values. So bss_start is obtained using an
3340 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3341 directly. You should not need to touch this setting.
3344 The following definitions that deal with the placement and management
3345 of environment data (variable area); in general, we support the
3346 following configurations:
3348 - CONFIG_BUILD_ENVCRC:
3350 Builds up envcrc with the target environment so that external utils
3351 may easily extract it and embed it in final U-Boot images.
3353 - CONFIG_ENV_IS_IN_FLASH:
3355 Define this if the environment is in flash memory.
3357 a) The environment occupies one whole flash sector, which is
3358 "embedded" in the text segment with the U-Boot code. This
3359 happens usually with "bottom boot sector" or "top boot
3360 sector" type flash chips, which have several smaller
3361 sectors at the start or the end. For instance, such a
3362 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3363 such a case you would place the environment in one of the
3364 4 kB sectors - with U-Boot code before and after it. With
3365 "top boot sector" type flash chips, you would put the
3366 environment in one of the last sectors, leaving a gap
3367 between U-Boot and the environment.
3369 - CONFIG_ENV_OFFSET:
3371 Offset of environment data (variable area) to the
3372 beginning of flash memory; for instance, with bottom boot
3373 type flash chips the second sector can be used: the offset
3374 for this sector is given here.
3376 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3380 This is just another way to specify the start address of
3381 the flash sector containing the environment (instead of
3384 - CONFIG_ENV_SECT_SIZE:
3386 Size of the sector containing the environment.
3389 b) Sometimes flash chips have few, equal sized, BIG sectors.
3390 In such a case you don't want to spend a whole sector for
3395 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3396 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3397 of this flash sector for the environment. This saves
3398 memory for the RAM copy of the environment.
3400 It may also save flash memory if you decide to use this
3401 when your environment is "embedded" within U-Boot code,
3402 since then the remainder of the flash sector could be used
3403 for U-Boot code. It should be pointed out that this is
3404 STRONGLY DISCOURAGED from a robustness point of view:
3405 updating the environment in flash makes it always
3406 necessary to erase the WHOLE sector. If something goes
3407 wrong before the contents has been restored from a copy in
3408 RAM, your target system will be dead.
3410 - CONFIG_ENV_ADDR_REDUND
3411 CONFIG_ENV_SIZE_REDUND
3413 These settings describe a second storage area used to hold
3414 a redundant copy of the environment data, so that there is
3415 a valid backup copy in case there is a power failure during
3416 a "saveenv" operation.
3418 BE CAREFUL! Any changes to the flash layout, and some changes to the
3419 source code will make it necessary to adapt <board>/u-boot.lds*
3423 - CONFIG_ENV_IS_IN_NVRAM:
3425 Define this if you have some non-volatile memory device
3426 (NVRAM, battery buffered SRAM) which you want to use for the
3432 These two #defines are used to determine the memory area you
3433 want to use for environment. It is assumed that this memory
3434 can just be read and written to, without any special
3437 BE CAREFUL! The first access to the environment happens quite early
3438 in U-Boot initalization (when we try to get the setting of for the
3439 console baudrate). You *MUST* have mapped your NVRAM area then, or
3442 Please note that even with NVRAM we still use a copy of the
3443 environment in RAM: we could work on NVRAM directly, but we want to
3444 keep settings there always unmodified except somebody uses "saveenv"
3445 to save the current settings.
3448 - CONFIG_ENV_IS_IN_EEPROM:
3450 Use this if you have an EEPROM or similar serial access
3451 device and a driver for it.
3453 - CONFIG_ENV_OFFSET:
3456 These two #defines specify the offset and size of the
3457 environment area within the total memory of your EEPROM.
3459 - CONFIG_SYS_I2C_EEPROM_ADDR:
3460 If defined, specified the chip address of the EEPROM device.
3461 The default address is zero.
3463 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3464 If defined, the number of bits used to address bytes in a
3465 single page in the EEPROM device. A 64 byte page, for example
3466 would require six bits.
3468 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3469 If defined, the number of milliseconds to delay between
3470 page writes. The default is zero milliseconds.
3472 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3473 The length in bytes of the EEPROM memory array address. Note
3474 that this is NOT the chip address length!
3476 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3477 EEPROM chips that implement "address overflow" are ones
3478 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3479 address and the extra bits end up in the "chip address" bit
3480 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3483 Note that we consider the length of the address field to
3484 still be one byte because the extra address bits are hidden
3485 in the chip address.
3487 - CONFIG_SYS_EEPROM_SIZE:
3488 The size in bytes of the EEPROM device.
3490 - CONFIG_ENV_EEPROM_IS_ON_I2C
3491 define this, if you have I2C and SPI activated, and your
3492 EEPROM, which holds the environment, is on the I2C bus.
3494 - CONFIG_I2C_ENV_EEPROM_BUS
3495 if you have an Environment on an EEPROM reached over
3496 I2C muxes, you can define here, how to reach this
3497 EEPROM. For example:
3499 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3501 EEPROM which holds the environment, is reached over
3502 a pca9547 i2c mux with address 0x70, channel 3.
3504 - CONFIG_ENV_IS_IN_DATAFLASH:
3506 Define this if you have a DataFlash memory device which you
3507 want to use for the environment.
3509 - CONFIG_ENV_OFFSET:
3513 These three #defines specify the offset and size of the
3514 environment area within the total memory of your DataFlash placed
3515 at the specified address.
3517 - CONFIG_ENV_IS_IN_REMOTE:
3519 Define this if you have a remote memory space which you
3520 want to use for the local device's environment.
3525 These two #defines specify the address and size of the
3526 environment area within the remote memory space. The
3527 local device can get the environment from remote memory
3528 space by SRIO or PCIE links.
3530 BE CAREFUL! For some special cases, the local device can not use
3531 "saveenv" command. For example, the local device will get the
3532 environment stored in a remote NOR flash by SRIO or PCIE link,
3533 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3535 - CONFIG_ENV_IS_IN_NAND:
3537 Define this if you have a NAND device which you want to use
3538 for the environment.
3540 - CONFIG_ENV_OFFSET:
3543 These two #defines specify the offset and size of the environment
3544 area within the first NAND device. CONFIG_ENV_OFFSET must be
3545 aligned to an erase block boundary.
3547 - CONFIG_ENV_OFFSET_REDUND (optional):
3549 This setting describes a second storage area of CONFIG_ENV_SIZE
3550 size used to hold a redundant copy of the environment data, so
3551 that there is a valid backup copy in case there is a power failure
3552 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3553 aligned to an erase block boundary.
3555 - CONFIG_ENV_RANGE (optional):
3557 Specifies the length of the region in which the environment
3558 can be written. This should be a multiple of the NAND device's
3559 block size. Specifying a range with more erase blocks than
3560 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3561 the range to be avoided.
3563 - CONFIG_ENV_OFFSET_OOB (optional):
3565 Enables support for dynamically retrieving the offset of the
3566 environment from block zero's out-of-band data. The
3567 "nand env.oob" command can be used to record this offset.
3568 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3569 using CONFIG_ENV_OFFSET_OOB.
3571 - CONFIG_NAND_ENV_DST
3573 Defines address in RAM to which the nand_spl code should copy the
3574 environment. If redundant environment is used, it will be copied to
3575 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3577 - CONFIG_ENV_IS_IN_UBI:
3579 Define this if you have an UBI volume that you want to use for the
3580 environment. This has the benefit of wear-leveling the environment
3581 accesses, which is important on NAND.
3583 - CONFIG_ENV_UBI_PART:
3585 Define this to a string that is the mtd partition containing the UBI.
3587 - CONFIG_ENV_UBI_VOLUME:
3589 Define this to the name of the volume that you want to store the
3592 - CONFIG_ENV_UBI_VOLUME_REDUND:
3594 Define this to the name of another volume to store a second copy of
3595 the environment in. This will enable redundant environments in UBI.
3596 It is assumed that both volumes are in the same MTD partition.
3598 - CONFIG_UBI_SILENCE_MSG
3599 - CONFIG_UBIFS_SILENCE_MSG
3601 You will probably want to define these to avoid a really noisy system
3602 when storing the env in UBI.
3604 - CONFIG_SYS_SPI_INIT_OFFSET
3606 Defines offset to the initial SPI buffer area in DPRAM. The
3607 area is used at an early stage (ROM part) if the environment
3608 is configured to reside in the SPI EEPROM: We need a 520 byte
3609 scratch DPRAM area. It is used between the two initialization
3610 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3611 to be a good choice since it makes it far enough from the
3612 start of the data area as well as from the stack pointer.
3614 Please note that the environment is read-only until the monitor
3615 has been relocated to RAM and a RAM copy of the environment has been
3616 created; also, when using EEPROM you will have to use getenv_f()
3617 until then to read environment variables.
3619 The environment is protected by a CRC32 checksum. Before the monitor
3620 is relocated into RAM, as a result of a bad CRC you will be working
3621 with the compiled-in default environment - *silently*!!! [This is
3622 necessary, because the first environment variable we need is the
3623 "baudrate" setting for the console - if we have a bad CRC, we don't
3624 have any device yet where we could complain.]
3626 Note: once the monitor has been relocated, then it will complain if
3627 the default environment is used; a new CRC is computed as soon as you
3628 use the "saveenv" command to store a valid environment.
3630 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3631 Echo the inverted Ethernet link state to the fault LED.
3633 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3634 also needs to be defined.
3636 - CONFIG_SYS_FAULT_MII_ADDR:
3637 MII address of the PHY to check for the Ethernet link state.
3639 - CONFIG_NS16550_MIN_FUNCTIONS:
3640 Define this if you desire to only have use of the NS16550_init
3641 and NS16550_putc functions for the serial driver located at
3642 drivers/serial/ns16550.c. This option is useful for saving
3643 space for already greatly restricted images, including but not
3644 limited to NAND_SPL configurations.
3646 - CONFIG_DISPLAY_BOARDINFO
3647 Display information about the board that U-Boot is running on
3648 when U-Boot starts up. The board function checkboard() is called
3651 - CONFIG_DISPLAY_BOARDINFO_LATE
3652 Similar to the previous option, but display this information
3653 later, once stdio is running and output goes to the LCD, if
3656 Low Level (hardware related) configuration options:
3657 ---------------------------------------------------
3659 - CONFIG_SYS_CACHELINE_SIZE:
3660 Cache Line Size of the CPU.
3662 - CONFIG_SYS_DEFAULT_IMMR:
3663 Default address of the IMMR after system reset.
3665 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3666 and RPXsuper) to be able to adjust the position of
3667 the IMMR register after a reset.
3669 - CONFIG_SYS_CCSRBAR_DEFAULT:
3670 Default (power-on reset) physical address of CCSR on Freescale
3673 - CONFIG_SYS_CCSRBAR:
3674 Virtual address of CCSR. On a 32-bit build, this is typically
3675 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3677 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3678 for cross-platform code that uses that macro instead.
3680 - CONFIG_SYS_CCSRBAR_PHYS:
3681 Physical address of CCSR. CCSR can be relocated to a new
3682 physical address, if desired. In this case, this macro should
3683 be set to that address. Otherwise, it should be set to the
3684 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3685 is typically relocated on 36-bit builds. It is recommended
3686 that this macro be defined via the _HIGH and _LOW macros:
3688 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3689 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3691 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3692 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3693 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3694 used in assembly code, so it must not contain typecasts or
3695 integer size suffixes (e.g. "ULL").
3697 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3698 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3699 used in assembly code, so it must not contain typecasts or
3700 integer size suffixes (e.g. "ULL").
3702 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3703 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3704 forced to a value that ensures that CCSR is not relocated.
3706 - Floppy Disk Support:
3707 CONFIG_SYS_FDC_DRIVE_NUMBER
3709 the default drive number (default value 0)
3711 CONFIG_SYS_ISA_IO_STRIDE
3713 defines the spacing between FDC chipset registers
3716 CONFIG_SYS_ISA_IO_OFFSET
3718 defines the offset of register from address. It
3719 depends on which part of the data bus is connected to
3720 the FDC chipset. (default value 0)
3722 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3723 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3726 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3727 fdc_hw_init() is called at the beginning of the FDC
3728 setup. fdc_hw_init() must be provided by the board
3729 source code. It is used to make hardware dependant
3733 Most IDE controllers were designed to be connected with PCI
3734 interface. Only few of them were designed for AHB interface.
3735 When software is doing ATA command and data transfer to
3736 IDE devices through IDE-AHB controller, some additional
3737 registers accessing to these kind of IDE-AHB controller
3740 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3741 DO NOT CHANGE unless you know exactly what you're
3742 doing! (11-4) [MPC8xx/82xx systems only]
3744 - CONFIG_SYS_INIT_RAM_ADDR:
3746 Start address of memory area that can be used for
3747 initial data and stack; please note that this must be
3748 writable memory that is working WITHOUT special
3749 initialization, i. e. you CANNOT use normal RAM which
3750 will become available only after programming the
3751 memory controller and running certain initialization
3754 U-Boot uses the following memory types:
3755 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3756 - MPC824X: data cache
3757 - PPC4xx: data cache
3759 - CONFIG_SYS_GBL_DATA_OFFSET:
3761 Offset of the initial data structure in the memory
3762 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3763 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3764 data is located at the end of the available space
3765 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3766 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3767 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3768 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3771 On the MPC824X (or other systems that use the data
3772 cache for initial memory) the address chosen for
3773 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3774 point to an otherwise UNUSED address space between
3775 the top of RAM and the start of the PCI space.
3777 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3779 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3781 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3783 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3785 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3787 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3789 - CONFIG_SYS_OR_TIMING_SDRAM:
3792 - CONFIG_SYS_MAMR_PTA:
3793 periodic timer for refresh
3795 - CONFIG_SYS_DER: Debug Event Register (37-47)
3797 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3798 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3799 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3800 CONFIG_SYS_BR1_PRELIM:
3801 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3803 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3804 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3805 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3806 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3808 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3809 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3810 Machine Mode Register and Memory Periodic Timer
3811 Prescaler definitions (SDRAM timing)
3813 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3814 enable I2C microcode relocation patch (MPC8xx);
3815 define relocation offset in DPRAM [DSP2]
3817 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3818 enable SMC microcode relocation patch (MPC8xx);
3819 define relocation offset in DPRAM [SMC1]
3821 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3822 enable SPI microcode relocation patch (MPC8xx);
3823 define relocation offset in DPRAM [SCC4]
3825 - CONFIG_SYS_USE_OSCCLK:
3826 Use OSCM clock mode on MBX8xx board. Be careful,
3827 wrong setting might damage your board. Read
3828 doc/README.MBX before setting this variable!
3830 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3831 Offset of the bootmode word in DPRAM used by post
3832 (Power On Self Tests). This definition overrides
3833 #define'd default value in commproc.h resp.
3836 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3837 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3838 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3839 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3840 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3841 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3842 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3843 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3844 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3846 - CONFIG_PCI_DISABLE_PCIE:
3847 Disable PCI-Express on systems where it is supported but not
3850 - CONFIG_PCI_ENUM_ONLY
3851 Only scan through and get the devices on the busses.
3852 Don't do any setup work, presumably because someone or
3853 something has already done it, and we don't need to do it
3854 a second time. Useful for platforms that are pre-booted
3855 by coreboot or similar.
3858 Chip has SRIO or not
3861 Board has SRIO 1 port available
3864 Board has SRIO 2 port available
3866 - CONFIG_SYS_SRIOn_MEM_VIRT:
3867 Virtual Address of SRIO port 'n' memory region
3869 - CONFIG_SYS_SRIOn_MEM_PHYS:
3870 Physical Address of SRIO port 'n' memory region
3872 - CONFIG_SYS_SRIOn_MEM_SIZE:
3873 Size of SRIO port 'n' memory region
3875 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3876 Defined to tell the NAND controller that the NAND chip is using
3878 Not all NAND drivers use this symbol.
3879 Example of drivers that use it:
3880 - drivers/mtd/nand/ndfc.c
3881 - drivers/mtd/nand/mxc_nand.c
3883 - CONFIG_SYS_NDFC_EBC0_CFG
3884 Sets the EBC0_CFG register for the NDFC. If not defined
3885 a default value will be used.
3888 Get DDR timing information from an I2C EEPROM. Common
3889 with pluggable memory modules such as SODIMMs
3892 I2C address of the SPD EEPROM
3894 - CONFIG_SYS_SPD_BUS_NUM
3895 If SPD EEPROM is on an I2C bus other than the first
3896 one, specify here. Note that the value must resolve
3897 to something your driver can deal with.
3899 - CONFIG_SYS_DDR_RAW_TIMING
3900 Get DDR timing information from other than SPD. Common with
3901 soldered DDR chips onboard without SPD. DDR raw timing
3902 parameters are extracted from datasheet and hard-coded into
3903 header files or board specific files.
3905 - CONFIG_FSL_DDR_INTERACTIVE
3906 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3908 - CONFIG_SYS_83XX_DDR_USES_CS0
3909 Only for 83xx systems. If specified, then DDR should
3910 be configured using CS0 and CS1 instead of CS2 and CS3.
3912 - CONFIG_ETHER_ON_FEC[12]
3913 Define to enable FEC[12] on a 8xx series processor.
3915 - CONFIG_FEC[12]_PHY
3916 Define to the hardcoded PHY address which corresponds
3917 to the given FEC; i. e.
3918 #define CONFIG_FEC1_PHY 4
3919 means that the PHY with address 4 is connected to FEC1
3921 When set to -1, means to probe for first available.
3923 - CONFIG_FEC[12]_PHY_NORXERR
3924 The PHY does not have a RXERR line (RMII only).
3925 (so program the FEC to ignore it).
3928 Enable RMII mode for all FECs.
3929 Note that this is a global option, we can't
3930 have one FEC in standard MII mode and another in RMII mode.
3932 - CONFIG_CRC32_VERIFY
3933 Add a verify option to the crc32 command.
3936 => crc32 -v <address> <count> <crc32>
3938 Where address/count indicate a memory area
3939 and crc32 is the correct crc32 which the
3943 Add the "loopw" memory command. This only takes effect if
3944 the memory commands are activated globally (CONFIG_CMD_MEM).
3947 Add the "mdc" and "mwc" memory commands. These are cyclic
3952 This command will print 4 bytes (10,11,12,13) each 500 ms.
3954 => mwc.l 100 12345678 10
3955 This command will write 12345678 to address 100 all 10 ms.
3957 This only takes effect if the memory commands are activated
3958 globally (CONFIG_CMD_MEM).
3960 - CONFIG_SKIP_LOWLEVEL_INIT
3961 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3962 low level initializations (like setting up the memory
3963 controller) are omitted and/or U-Boot does not
3964 relocate itself into RAM.
3966 Normally this variable MUST NOT be defined. The only
3967 exception is when U-Boot is loaded (to RAM) by some
3968 other boot loader or by a debugger which performs
3969 these initializations itself.
3972 Modifies the behaviour of start.S when compiling a loader
3973 that is executed before the actual U-Boot. E.g. when
3974 compiling a NAND SPL.
3976 - CONFIG_ARCH_MAP_SYSMEM
3977 Generally U-Boot (and in particular the md command) uses
3978 effective address. It is therefore not necessary to regard
3979 U-Boot address as virtual addresses that need to be translated
3980 to physical addresses. However, sandbox requires this, since
3981 it maintains its own little RAM buffer which contains all
3982 addressable memory. This option causes some memory accesses
3983 to be mapped through map_sysmem() / unmap_sysmem().
3985 - CONFIG_USE_ARCH_MEMCPY
3986 CONFIG_USE_ARCH_MEMSET
3987 If these options are used a optimized version of memcpy/memset will
3988 be used if available. These functions may be faster under some
3989 conditions but may increase the binary size.
3991 - CONFIG_X86_RESET_VECTOR
3992 If defined, the x86 reset vector code is included. This is not
3993 needed when U-Boot is running from Coreboot.
3996 Defines the MPU clock speed (in MHz).
3998 NOTE : currently only supported on AM335x platforms.
4000 Freescale QE/FMAN Firmware Support:
4001 -----------------------------------
4003 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4004 loading of "firmware", which is encoded in the QE firmware binary format.
4005 This firmware often needs to be loaded during U-Boot booting, so macros
4006 are used to identify the storage device (NOR flash, SPI, etc) and the address
4009 - CONFIG_SYS_QE_FMAN_FW_ADDR
4010 The address in the storage device where the firmware is located. The
4011 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4014 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4015 The maximum possible size of the firmware. The firmware binary format
4016 has a field that specifies the actual size of the firmware, but it
4017 might not be possible to read any part of the firmware unless some
4018 local storage is allocated to hold the entire firmware first.
4020 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4021 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4022 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4023 virtual address in NOR flash.
4025 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4026 Specifies that QE/FMAN firmware is located in NAND flash.
4027 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4029 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4030 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4031 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4033 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4034 Specifies that QE/FMAN firmware is located on the primary SPI
4035 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4037 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4038 Specifies that QE/FMAN firmware is located in the remote (master)
4039 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4040 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4041 window->master inbound window->master LAW->the ucode address in
4042 master's memory space.
4044 Building the Software:
4045 ======================
4047 Building U-Boot has been tested in several native build environments
4048 and in many different cross environments. Of course we cannot support
4049 all possibly existing versions of cross development tools in all
4050 (potentially obsolete) versions. In case of tool chain problems we
4051 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4052 which is extensively used to build and test U-Boot.
4054 If you are not using a native environment, it is assumed that you
4055 have GNU cross compiling tools available in your path. In this case,
4056 you must set the environment variable CROSS_COMPILE in your shell.
4057 Note that no changes to the Makefile or any other source files are
4058 necessary. For example using the ELDK on a 4xx CPU, please enter:
4060 $ CROSS_COMPILE=ppc_4xx-
4061 $ export CROSS_COMPILE
4063 Note: If you wish to generate Windows versions of the utilities in
4064 the tools directory you can use the MinGW toolchain
4065 (http://www.mingw.org). Set your HOST tools to the MinGW
4066 toolchain and execute 'make tools'. For example:
4068 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4070 Binaries such as tools/mkimage.exe will be created which can
4071 be executed on computers running Windows.
4073 U-Boot is intended to be simple to build. After installing the
4074 sources you must configure U-Boot for one specific board type. This
4079 where "NAME_config" is the name of one of the existing configu-
4080 rations; see boards.cfg for supported names.
4082 Note: for some board special configuration names may exist; check if
4083 additional information is available from the board vendor; for
4084 instance, the TQM823L systems are available without (standard)
4085 or with LCD support. You can select such additional "features"
4086 when choosing the configuration, i. e.
4089 - will configure for a plain TQM823L, i. e. no LCD support
4091 make TQM823L_LCD_config
4092 - will configure for a TQM823L with U-Boot console on LCD
4097 Finally, type "make all", and you should get some working U-Boot
4098 images ready for download to / installation on your system:
4100 - "u-boot.bin" is a raw binary image
4101 - "u-boot" is an image in ELF binary format
4102 - "u-boot.srec" is in Motorola S-Record format
4104 By default the build is performed locally and the objects are saved
4105 in the source directory. One of the two methods can be used to change
4106 this behavior and build U-Boot to some external directory:
4108 1. Add O= to the make command line invocations:
4110 make O=/tmp/build distclean
4111 make O=/tmp/build NAME_config
4112 make O=/tmp/build all
4114 2. Set environment variable BUILD_DIR to point to the desired location:
4116 export BUILD_DIR=/tmp/build
4121 Note that the command line "O=" setting overrides the BUILD_DIR environment
4125 Please be aware that the Makefiles assume you are using GNU make, so
4126 for instance on NetBSD you might need to use "gmake" instead of
4130 If the system board that you have is not listed, then you will need
4131 to port U-Boot to your hardware platform. To do this, follow these
4134 1. Add a new configuration option for your board to the toplevel
4135 "boards.cfg" file, using the existing entries as examples.
4136 Follow the instructions there to keep the boards in order.
4137 2. Create a new directory to hold your board specific code. Add any
4138 files you need. In your board directory, you will need at least
4139 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4140 3. Create a new configuration file "include/configs/<board>.h" for
4142 3. If you're porting U-Boot to a new CPU, then also create a new
4143 directory to hold your CPU specific code. Add any files you need.
4144 4. Run "make <board>_config" with your new name.
4145 5. Type "make", and you should get a working "u-boot.srec" file
4146 to be installed on your target system.
4147 6. Debug and solve any problems that might arise.
4148 [Of course, this last step is much harder than it sounds.]
4151 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4152 ==============================================================
4154 If you have modified U-Boot sources (for instance added a new board
4155 or support for new devices, a new CPU, etc.) you are expected to
4156 provide feedback to the other developers. The feedback normally takes
4157 the form of a "patch", i. e. a context diff against a certain (latest
4158 official or latest in the git repository) version of U-Boot sources.
4160 But before you submit such a patch, please verify that your modifi-
4161 cation did not break existing code. At least make sure that *ALL* of
4162 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4163 just run the "MAKEALL" script, which will configure and build U-Boot
4164 for ALL supported system. Be warned, this will take a while. You can
4165 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4166 environment variable to the script, i. e. to use the ELDK cross tools
4169 CROSS_COMPILE=ppc_8xx- MAKEALL
4171 or to build on a native PowerPC system you can type
4173 CROSS_COMPILE=' ' MAKEALL
4175 When using the MAKEALL script, the default behaviour is to build
4176 U-Boot in the source directory. This location can be changed by
4177 setting the BUILD_DIR environment variable. Also, for each target
4178 built, the MAKEALL script saves two log files (<target>.ERR and
4179 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4180 location can be changed by setting the MAKEALL_LOGDIR environment
4181 variable. For example:
4183 export BUILD_DIR=/tmp/build
4184 export MAKEALL_LOGDIR=/tmp/log
4185 CROSS_COMPILE=ppc_8xx- MAKEALL
4187 With the above settings build objects are saved in the /tmp/build,
4188 log files are saved in the /tmp/log and the source tree remains clean
4189 during the whole build process.
4192 See also "U-Boot Porting Guide" below.
4195 Monitor Commands - Overview:
4196 ============================
4198 go - start application at address 'addr'
4199 run - run commands in an environment variable
4200 bootm - boot application image from memory
4201 bootp - boot image via network using BootP/TFTP protocol
4202 bootz - boot zImage from memory
4203 tftpboot- boot image via network using TFTP protocol
4204 and env variables "ipaddr" and "serverip"
4205 (and eventually "gatewayip")
4206 tftpput - upload a file via network using TFTP protocol
4207 rarpboot- boot image via network using RARP/TFTP protocol
4208 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4209 loads - load S-Record file over serial line
4210 loadb - load binary file over serial line (kermit mode)
4212 mm - memory modify (auto-incrementing)
4213 nm - memory modify (constant address)
4214 mw - memory write (fill)
4216 cmp - memory compare
4217 crc32 - checksum calculation
4218 i2c - I2C sub-system
4219 sspi - SPI utility commands
4220 base - print or set address offset
4221 printenv- print environment variables
4222 setenv - set environment variables
4223 saveenv - save environment variables to persistent storage
4224 protect - enable or disable FLASH write protection
4225 erase - erase FLASH memory
4226 flinfo - print FLASH memory information
4227 nand - NAND memory operations (see doc/README.nand)
4228 bdinfo - print Board Info structure
4229 iminfo - print header information for application image
4230 coninfo - print console devices and informations
4231 ide - IDE sub-system
4232 loop - infinite loop on address range
4233 loopw - infinite write loop on address range
4234 mtest - simple RAM test
4235 icache - enable or disable instruction cache
4236 dcache - enable or disable data cache
4237 reset - Perform RESET of the CPU
4238 echo - echo args to console
4239 version - print monitor version
4240 help - print online help
4241 ? - alias for 'help'
4244 Monitor Commands - Detailed Description:
4245 ========================================
4249 For now: just type "help <command>".
4252 Environment Variables:
4253 ======================
4255 U-Boot supports user configuration using Environment Variables which
4256 can be made persistent by saving to Flash memory.
4258 Environment Variables are set using "setenv", printed using
4259 "printenv", and saved to Flash using "saveenv". Using "setenv"
4260 without a value can be used to delete a variable from the
4261 environment. As long as you don't save the environment you are
4262 working with an in-memory copy. In case the Flash area containing the
4263 environment is erased by accident, a default environment is provided.
4265 Some configuration options can be set using Environment Variables.
4267 List of environment variables (most likely not complete):
4269 baudrate - see CONFIG_BAUDRATE
4271 bootdelay - see CONFIG_BOOTDELAY
4273 bootcmd - see CONFIG_BOOTCOMMAND
4275 bootargs - Boot arguments when booting an RTOS image
4277 bootfile - Name of the image to load with TFTP
4279 bootm_low - Memory range available for image processing in the bootm
4280 command can be restricted. This variable is given as
4281 a hexadecimal number and defines lowest address allowed
4282 for use by the bootm command. See also "bootm_size"
4283 environment variable. Address defined by "bootm_low" is
4284 also the base of the initial memory mapping for the Linux
4285 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4288 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4289 This variable is given as a hexadecimal number and it
4290 defines the size of the memory region starting at base
4291 address bootm_low that is accessible by the Linux kernel
4292 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4293 as the default value if it is defined, and bootm_size is
4296 bootm_size - Memory range available for image processing in the bootm
4297 command can be restricted. This variable is given as
4298 a hexadecimal number and defines the size of the region
4299 allowed for use by the bootm command. See also "bootm_low"
4300 environment variable.
4302 updatefile - Location of the software update file on a TFTP server, used
4303 by the automatic software update feature. Please refer to
4304 documentation in doc/README.update for more details.
4306 autoload - if set to "no" (any string beginning with 'n'),
4307 "bootp" will just load perform a lookup of the
4308 configuration from the BOOTP server, but not try to
4309 load any image using TFTP
4311 autostart - if set to "yes", an image loaded using the "bootp",
4312 "rarpboot", "tftpboot" or "diskboot" commands will
4313 be automatically started (by internally calling
4316 If set to "no", a standalone image passed to the
4317 "bootm" command will be copied to the load address
4318 (and eventually uncompressed), but NOT be started.
4319 This can be used to load and uncompress arbitrary
4322 fdt_high - if set this restricts the maximum address that the
4323 flattened device tree will be copied into upon boot.
4324 For example, if you have a system with 1 GB memory
4325 at physical address 0x10000000, while Linux kernel
4326 only recognizes the first 704 MB as low memory, you
4327 may need to set fdt_high as 0x3C000000 to have the
4328 device tree blob be copied to the maximum address
4329 of the 704 MB low memory, so that Linux kernel can
4330 access it during the boot procedure.
4332 If this is set to the special value 0xFFFFFFFF then
4333 the fdt will not be copied at all on boot. For this
4334 to work it must reside in writable memory, have
4335 sufficient padding on the end of it for u-boot to
4336 add the information it needs into it, and the memory
4337 must be accessible by the kernel.
4339 fdtcontroladdr- if set this is the address of the control flattened
4340 device tree used by U-Boot when CONFIG_OF_CONTROL is
4343 i2cfast - (PPC405GP|PPC405EP only)
4344 if set to 'y' configures Linux I2C driver for fast
4345 mode (400kHZ). This environment variable is used in
4346 initialization code. So, for changes to be effective
4347 it must be saved and board must be reset.
4349 initrd_high - restrict positioning of initrd images:
4350 If this variable is not set, initrd images will be
4351 copied to the highest possible address in RAM; this
4352 is usually what you want since it allows for
4353 maximum initrd size. If for some reason you want to
4354 make sure that the initrd image is loaded below the
4355 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4356 variable to a value of "no" or "off" or "0".
4357 Alternatively, you can set it to a maximum upper
4358 address to use (U-Boot will still check that it
4359 does not overwrite the U-Boot stack and data).
4361 For instance, when you have a system with 16 MB
4362 RAM, and want to reserve 4 MB from use by Linux,
4363 you can do this by adding "mem=12M" to the value of
4364 the "bootargs" variable. However, now you must make
4365 sure that the initrd image is placed in the first
4366 12 MB as well - this can be done with
4368 setenv initrd_high 00c00000
4370 If you set initrd_high to 0xFFFFFFFF, this is an
4371 indication to U-Boot that all addresses are legal
4372 for the Linux kernel, including addresses in flash
4373 memory. In this case U-Boot will NOT COPY the
4374 ramdisk at all. This may be useful to reduce the
4375 boot time on your system, but requires that this
4376 feature is supported by your Linux kernel.
4378 ipaddr - IP address; needed for tftpboot command
4380 loadaddr - Default load address for commands like "bootp",
4381 "rarpboot", "tftpboot", "loadb" or "diskboot"
4383 loads_echo - see CONFIG_LOADS_ECHO
4385 serverip - TFTP server IP address; needed for tftpboot command
4387 bootretry - see CONFIG_BOOT_RETRY_TIME
4389 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4391 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4393 ethprime - controls which interface is used first.
4395 ethact - controls which interface is currently active.
4396 For example you can do the following
4398 => setenv ethact FEC
4399 => ping 192.168.0.1 # traffic sent on FEC
4400 => setenv ethact SCC
4401 => ping 10.0.0.1 # traffic sent on SCC
4403 ethrotate - When set to "no" U-Boot does not go through all
4404 available network interfaces.
4405 It just stays at the currently selected interface.
4407 netretry - When set to "no" each network operation will
4408 either succeed or fail without retrying.
4409 When set to "once" the network operation will
4410 fail when all the available network interfaces
4411 are tried once without success.
4412 Useful on scripts which control the retry operation
4415 npe_ucode - set load address for the NPE microcode
4417 tftpsrcport - If this is set, the value is used for TFTP's
4420 tftpdstport - If this is set, the value is used for TFTP's UDP
4421 destination port instead of the Well Know Port 69.
4423 tftpblocksize - Block size to use for TFTP transfers; if not set,
4424 we use the TFTP server's default block size
4426 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4427 seconds, minimum value is 1000 = 1 second). Defines
4428 when a packet is considered to be lost so it has to
4429 be retransmitted. The default is 5000 = 5 seconds.
4430 Lowering this value may make downloads succeed
4431 faster in networks with high packet loss rates or
4432 with unreliable TFTP servers.
4434 vlan - When set to a value < 4095 the traffic over
4435 Ethernet is encapsulated/received over 802.1q
4438 The following image location variables contain the location of images
4439 used in booting. The "Image" column gives the role of the image and is
4440 not an environment variable name. The other columns are environment
4441 variable names. "File Name" gives the name of the file on a TFTP
4442 server, "RAM Address" gives the location in RAM the image will be
4443 loaded to, and "Flash Location" gives the image's address in NOR
4444 flash or offset in NAND flash.
4446 *Note* - these variables don't have to be defined for all boards, some
4447 boards currenlty use other variables for these purposes, and some
4448 boards use these variables for other purposes.
4450 Image File Name RAM Address Flash Location
4451 ----- --------- ----------- --------------
4452 u-boot u-boot u-boot_addr_r u-boot_addr
4453 Linux kernel bootfile kernel_addr_r kernel_addr
4454 device tree blob fdtfile fdt_addr_r fdt_addr
4455 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4457 The following environment variables may be used and automatically
4458 updated by the network boot commands ("bootp" and "rarpboot"),
4459 depending the information provided by your boot server:
4461 bootfile - see above
4462 dnsip - IP address of your Domain Name Server
4463 dnsip2 - IP address of your secondary Domain Name Server
4464 gatewayip - IP address of the Gateway (Router) to use
4465 hostname - Target hostname
4467 netmask - Subnet Mask
4468 rootpath - Pathname of the root filesystem on the NFS server
4469 serverip - see above
4472 There are two special Environment Variables:
4474 serial# - contains hardware identification information such
4475 as type string and/or serial number
4476 ethaddr - Ethernet address
4478 These variables can be set only once (usually during manufacturing of
4479 the board). U-Boot refuses to delete or overwrite these variables
4480 once they have been set once.
4483 Further special Environment Variables:
4485 ver - Contains the U-Boot version string as printed
4486 with the "version" command. This variable is
4487 readonly (see CONFIG_VERSION_VARIABLE).
4490 Please note that changes to some configuration parameters may take
4491 only effect after the next boot (yes, that's just like Windoze :-).
4494 Callback functions for environment variables:
4495 ---------------------------------------------
4497 For some environment variables, the behavior of u-boot needs to change
4498 when their values are changed. This functionailty allows functions to
4499 be associated with arbitrary variables. On creation, overwrite, or
4500 deletion, the callback will provide the opportunity for some side
4501 effect to happen or for the change to be rejected.
4503 The callbacks are named and associated with a function using the
4504 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4506 These callbacks are associated with variables in one of two ways. The
4507 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4508 in the board configuration to a string that defines a list of
4509 associations. The list must be in the following format:
4511 entry = variable_name[:callback_name]
4514 If the callback name is not specified, then the callback is deleted.
4515 Spaces are also allowed anywhere in the list.
4517 Callbacks can also be associated by defining the ".callbacks" variable
4518 with the same list format above. Any association in ".callbacks" will
4519 override any association in the static list. You can define
4520 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4521 ".callbacks" envirnoment variable in the default or embedded environment.
4524 Command Line Parsing:
4525 =====================
4527 There are two different command line parsers available with U-Boot:
4528 the old "simple" one, and the much more powerful "hush" shell:
4530 Old, simple command line parser:
4531 --------------------------------
4533 - supports environment variables (through setenv / saveenv commands)
4534 - several commands on one line, separated by ';'
4535 - variable substitution using "... ${name} ..." syntax
4536 - special characters ('$', ';') can be escaped by prefixing with '\',
4538 setenv bootcmd bootm \${address}
4539 - You can also escape text by enclosing in single apostrophes, for example:
4540 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4545 - similar to Bourne shell, with control structures like
4546 if...then...else...fi, for...do...done; while...do...done,
4547 until...do...done, ...
4548 - supports environment ("global") variables (through setenv / saveenv
4549 commands) and local shell variables (through standard shell syntax
4550 "name=value"); only environment variables can be used with "run"
4556 (1) If a command line (or an environment variable executed by a "run"
4557 command) contains several commands separated by semicolon, and
4558 one of these commands fails, then the remaining commands will be
4561 (2) If you execute several variables with one call to run (i. e.
4562 calling run with a list of variables as arguments), any failing
4563 command will cause "run" to terminate, i. e. the remaining
4564 variables are not executed.
4566 Note for Redundant Ethernet Interfaces:
4567 =======================================
4569 Some boards come with redundant Ethernet interfaces; U-Boot supports
4570 such configurations and is capable of automatic selection of a
4571 "working" interface when needed. MAC assignment works as follows:
4573 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4574 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4575 "eth1addr" (=>eth1), "eth2addr", ...
4577 If the network interface stores some valid MAC address (for instance
4578 in SROM), this is used as default address if there is NO correspon-
4579 ding setting in the environment; if the corresponding environment
4580 variable is set, this overrides the settings in the card; that means:
4582 o If the SROM has a valid MAC address, and there is no address in the
4583 environment, the SROM's address is used.
4585 o If there is no valid address in the SROM, and a definition in the
4586 environment exists, then the value from the environment variable is
4589 o If both the SROM and the environment contain a MAC address, and
4590 both addresses are the same, this MAC address is used.
4592 o If both the SROM and the environment contain a MAC address, and the
4593 addresses differ, the value from the environment is used and a
4596 o If neither SROM nor the environment contain a MAC address, an error
4599 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4600 will be programmed into hardware as part of the initialization process. This
4601 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4602 The naming convention is as follows:
4603 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4608 U-Boot is capable of booting (and performing other auxiliary operations on)
4609 images in two formats:
4611 New uImage format (FIT)
4612 -----------------------
4614 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4615 to Flattened Device Tree). It allows the use of images with multiple
4616 components (several kernels, ramdisks, etc.), with contents protected by
4617 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4623 Old image format is based on binary files which can be basically anything,
4624 preceded by a special header; see the definitions in include/image.h for
4625 details; basically, the header defines the following image properties:
4627 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4628 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4629 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4630 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4632 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4633 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4634 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4635 * Compression Type (uncompressed, gzip, bzip2)
4641 The header is marked by a special Magic Number, and both the header
4642 and the data portions of the image are secured against corruption by
4649 Although U-Boot should support any OS or standalone application
4650 easily, the main focus has always been on Linux during the design of
4653 U-Boot includes many features that so far have been part of some
4654 special "boot loader" code within the Linux kernel. Also, any
4655 "initrd" images to be used are no longer part of one big Linux image;
4656 instead, kernel and "initrd" are separate images. This implementation
4657 serves several purposes:
4659 - the same features can be used for other OS or standalone
4660 applications (for instance: using compressed images to reduce the
4661 Flash memory footprint)
4663 - it becomes much easier to port new Linux kernel versions because
4664 lots of low-level, hardware dependent stuff are done by U-Boot
4666 - the same Linux kernel image can now be used with different "initrd"
4667 images; of course this also means that different kernel images can
4668 be run with the same "initrd". This makes testing easier (you don't
4669 have to build a new "zImage.initrd" Linux image when you just
4670 change a file in your "initrd"). Also, a field-upgrade of the
4671 software is easier now.
4677 Porting Linux to U-Boot based systems:
4678 ---------------------------------------
4680 U-Boot cannot save you from doing all the necessary modifications to
4681 configure the Linux device drivers for use with your target hardware
4682 (no, we don't intend to provide a full virtual machine interface to
4685 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4687 Just make sure your machine specific header file (for instance
4688 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4689 Information structure as we define in include/asm-<arch>/u-boot.h,
4690 and make sure that your definition of IMAP_ADDR uses the same value
4691 as your U-Boot configuration in CONFIG_SYS_IMMR.
4694 Configuring the Linux kernel:
4695 -----------------------------
4697 No specific requirements for U-Boot. Make sure you have some root
4698 device (initial ramdisk, NFS) for your target system.
4701 Building a Linux Image:
4702 -----------------------
4704 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4705 not used. If you use recent kernel source, a new build target
4706 "uImage" will exist which automatically builds an image usable by
4707 U-Boot. Most older kernels also have support for a "pImage" target,
4708 which was introduced for our predecessor project PPCBoot and uses a
4709 100% compatible format.
4718 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4719 encapsulate a compressed Linux kernel image with header information,
4720 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4722 * build a standard "vmlinux" kernel image (in ELF binary format):
4724 * convert the kernel into a raw binary image:
4726 ${CROSS_COMPILE}-objcopy -O binary \
4727 -R .note -R .comment \
4728 -S vmlinux linux.bin
4730 * compress the binary image:
4734 * package compressed binary image for U-Boot:
4736 mkimage -A ppc -O linux -T kernel -C gzip \
4737 -a 0 -e 0 -n "Linux Kernel Image" \
4738 -d linux.bin.gz uImage
4741 The "mkimage" tool can also be used to create ramdisk images for use
4742 with U-Boot, either separated from the Linux kernel image, or
4743 combined into one file. "mkimage" encapsulates the images with a 64
4744 byte header containing information about target architecture,
4745 operating system, image type, compression method, entry points, time
4746 stamp, CRC32 checksums, etc.
4748 "mkimage" can be called in two ways: to verify existing images and
4749 print the header information, or to build new images.
4751 In the first form (with "-l" option) mkimage lists the information
4752 contained in the header of an existing U-Boot image; this includes
4753 checksum verification:
4755 tools/mkimage -l image
4756 -l ==> list image header information
4758 The second form (with "-d" option) is used to build a U-Boot image
4759 from a "data file" which is used as image payload:
4761 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4762 -n name -d data_file image
4763 -A ==> set architecture to 'arch'
4764 -O ==> set operating system to 'os'
4765 -T ==> set image type to 'type'
4766 -C ==> set compression type 'comp'
4767 -a ==> set load address to 'addr' (hex)
4768 -e ==> set entry point to 'ep' (hex)
4769 -n ==> set image name to 'name'
4770 -d ==> use image data from 'datafile'
4772 Right now, all Linux kernels for PowerPC systems use the same load
4773 address (0x00000000), but the entry point address depends on the
4776 - 2.2.x kernels have the entry point at 0x0000000C,
4777 - 2.3.x and later kernels have the entry point at 0x00000000.
4779 So a typical call to build a U-Boot image would read:
4781 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4782 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4783 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4784 > examples/uImage.TQM850L
4785 Image Name: 2.4.4 kernel for TQM850L
4786 Created: Wed Jul 19 02:34:59 2000
4787 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4788 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4789 Load Address: 0x00000000
4790 Entry Point: 0x00000000
4792 To verify the contents of the image (or check for corruption):
4794 -> tools/mkimage -l examples/uImage.TQM850L
4795 Image Name: 2.4.4 kernel for TQM850L
4796 Created: Wed Jul 19 02:34:59 2000
4797 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4798 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4799 Load Address: 0x00000000
4800 Entry Point: 0x00000000
4802 NOTE: for embedded systems where boot time is critical you can trade
4803 speed for memory and install an UNCOMPRESSED image instead: this
4804 needs more space in Flash, but boots much faster since it does not
4805 need to be uncompressed:
4807 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4808 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4809 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4810 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4811 > examples/uImage.TQM850L-uncompressed
4812 Image Name: 2.4.4 kernel for TQM850L
4813 Created: Wed Jul 19 02:34:59 2000
4814 Image Type: PowerPC Linux Kernel Image (uncompressed)
4815 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4816 Load Address: 0x00000000
4817 Entry Point: 0x00000000
4820 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4821 when your kernel is intended to use an initial ramdisk:
4823 -> tools/mkimage -n 'Simple Ramdisk Image' \
4824 > -A ppc -O linux -T ramdisk -C gzip \
4825 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4826 Image Name: Simple Ramdisk Image
4827 Created: Wed Jan 12 14:01:50 2000
4828 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4829 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4830 Load Address: 0x00000000
4831 Entry Point: 0x00000000
4834 Installing a Linux Image:
4835 -------------------------
4837 To downloading a U-Boot image over the serial (console) interface,
4838 you must convert the image to S-Record format:
4840 objcopy -I binary -O srec examples/image examples/image.srec
4842 The 'objcopy' does not understand the information in the U-Boot
4843 image header, so the resulting S-Record file will be relative to
4844 address 0x00000000. To load it to a given address, you need to
4845 specify the target address as 'offset' parameter with the 'loads'
4848 Example: install the image to address 0x40100000 (which on the
4849 TQM8xxL is in the first Flash bank):
4851 => erase 40100000 401FFFFF
4857 ## Ready for S-Record download ...
4858 ~>examples/image.srec
4859 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4861 15989 15990 15991 15992
4862 [file transfer complete]
4864 ## Start Addr = 0x00000000
4867 You can check the success of the download using the 'iminfo' command;
4868 this includes a checksum verification so you can be sure no data
4869 corruption happened:
4873 ## Checking Image at 40100000 ...
4874 Image Name: 2.2.13 for initrd on TQM850L
4875 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4876 Data Size: 335725 Bytes = 327 kB = 0 MB
4877 Load Address: 00000000
4878 Entry Point: 0000000c
4879 Verifying Checksum ... OK
4885 The "bootm" command is used to boot an application that is stored in
4886 memory (RAM or Flash). In case of a Linux kernel image, the contents
4887 of the "bootargs" environment variable is passed to the kernel as
4888 parameters. You can check and modify this variable using the
4889 "printenv" and "setenv" commands:
4892 => printenv bootargs
4893 bootargs=root=/dev/ram
4895 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4897 => printenv bootargs
4898 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4901 ## Booting Linux kernel at 40020000 ...
4902 Image Name: 2.2.13 for NFS on TQM850L
4903 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4904 Data Size: 381681 Bytes = 372 kB = 0 MB
4905 Load Address: 00000000
4906 Entry Point: 0000000c
4907 Verifying Checksum ... OK
4908 Uncompressing Kernel Image ... OK
4909 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
4910 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4911 time_init: decrementer frequency = 187500000/60
4912 Calibrating delay loop... 49.77 BogoMIPS
4913 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4916 If you want to boot a Linux kernel with initial RAM disk, you pass
4917 the memory addresses of both the kernel and the initrd image (PPBCOOT
4918 format!) to the "bootm" command:
4920 => imi 40100000 40200000
4922 ## Checking Image at 40100000 ...
4923 Image Name: 2.2.13 for initrd on TQM850L
4924 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4925 Data Size: 335725 Bytes = 327 kB = 0 MB
4926 Load Address: 00000000
4927 Entry Point: 0000000c
4928 Verifying Checksum ... OK
4930 ## Checking Image at 40200000 ...
4931 Image Name: Simple Ramdisk Image
4932 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4933 Data Size: 566530 Bytes = 553 kB = 0 MB
4934 Load Address: 00000000
4935 Entry Point: 00000000
4936 Verifying Checksum ... OK
4938 => bootm 40100000 40200000
4939 ## Booting Linux kernel at 40100000 ...
4940 Image Name: 2.2.13 for initrd on TQM850L
4941 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4942 Data Size: 335725 Bytes = 327 kB = 0 MB
4943 Load Address: 00000000
4944 Entry Point: 0000000c
4945 Verifying Checksum ... OK
4946 Uncompressing Kernel Image ... OK
4947 ## Loading RAMDisk Image at 40200000 ...
4948 Image Name: Simple Ramdisk Image
4949 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4950 Data Size: 566530 Bytes = 553 kB = 0 MB
4951 Load Address: 00000000
4952 Entry Point: 00000000
4953 Verifying Checksum ... OK
4954 Loading Ramdisk ... OK
4955 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
4956 Boot arguments: root=/dev/ram
4957 time_init: decrementer frequency = 187500000/60
4958 Calibrating delay loop... 49.77 BogoMIPS
4960 RAMDISK: Compressed image found at block 0
4961 VFS: Mounted root (ext2 filesystem).
4965 Boot Linux and pass a flat device tree:
4968 First, U-Boot must be compiled with the appropriate defines. See the section
4969 titled "Linux Kernel Interface" above for a more in depth explanation. The
4970 following is an example of how to start a kernel and pass an updated
4976 oft=oftrees/mpc8540ads.dtb
4977 => tftp $oftaddr $oft
4978 Speed: 1000, full duplex
4980 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4981 Filename 'oftrees/mpc8540ads.dtb'.
4982 Load address: 0x300000
4985 Bytes transferred = 4106 (100a hex)
4986 => tftp $loadaddr $bootfile
4987 Speed: 1000, full duplex
4989 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4991 Load address: 0x200000
4992 Loading:############
4994 Bytes transferred = 1029407 (fb51f hex)
4999 => bootm $loadaddr - $oftaddr
5000 ## Booting image at 00200000 ...
5001 Image Name: Linux-2.6.17-dirty
5002 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5003 Data Size: 1029343 Bytes = 1005.2 kB
5004 Load Address: 00000000
5005 Entry Point: 00000000
5006 Verifying Checksum ... OK
5007 Uncompressing Kernel Image ... OK
5008 Booting using flat device tree at 0x300000
5009 Using MPC85xx ADS machine description
5010 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5014 More About U-Boot Image Types:
5015 ------------------------------
5017 U-Boot supports the following image types:
5019 "Standalone Programs" are directly runnable in the environment
5020 provided by U-Boot; it is expected that (if they behave
5021 well) you can continue to work in U-Boot after return from
5022 the Standalone Program.
5023 "OS Kernel Images" are usually images of some Embedded OS which
5024 will take over control completely. Usually these programs
5025 will install their own set of exception handlers, device
5026 drivers, set up the MMU, etc. - this means, that you cannot
5027 expect to re-enter U-Boot except by resetting the CPU.
5028 "RAMDisk Images" are more or less just data blocks, and their
5029 parameters (address, size) are passed to an OS kernel that is
5031 "Multi-File Images" contain several images, typically an OS
5032 (Linux) kernel image and one or more data images like
5033 RAMDisks. This construct is useful for instance when you want
5034 to boot over the network using BOOTP etc., where the boot
5035 server provides just a single image file, but you want to get
5036 for instance an OS kernel and a RAMDisk image.
5038 "Multi-File Images" start with a list of image sizes, each
5039 image size (in bytes) specified by an "uint32_t" in network
5040 byte order. This list is terminated by an "(uint32_t)0".
5041 Immediately after the terminating 0 follow the images, one by
5042 one, all aligned on "uint32_t" boundaries (size rounded up to
5043 a multiple of 4 bytes).
5045 "Firmware Images" are binary images containing firmware (like
5046 U-Boot or FPGA images) which usually will be programmed to
5049 "Script files" are command sequences that will be executed by
5050 U-Boot's command interpreter; this feature is especially
5051 useful when you configure U-Boot to use a real shell (hush)
5052 as command interpreter.
5054 Booting the Linux zImage:
5055 -------------------------
5057 On some platforms, it's possible to boot Linux zImage. This is done
5058 using the "bootz" command. The syntax of "bootz" command is the same
5059 as the syntax of "bootm" command.
5061 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
5062 kernel with raw initrd images. The syntax is slightly different, the
5063 address of the initrd must be augmented by it's size, in the following
5064 format: "<initrd addres>:<initrd size>".
5070 One of the features of U-Boot is that you can dynamically load and
5071 run "standalone" applications, which can use some resources of
5072 U-Boot like console I/O functions or interrupt services.
5074 Two simple examples are included with the sources:
5079 'examples/hello_world.c' contains a small "Hello World" Demo
5080 application; it is automatically compiled when you build U-Boot.
5081 It's configured to run at address 0x00040004, so you can play with it
5085 ## Ready for S-Record download ...
5086 ~>examples/hello_world.srec
5087 1 2 3 4 5 6 7 8 9 10 11 ...
5088 [file transfer complete]
5090 ## Start Addr = 0x00040004
5092 => go 40004 Hello World! This is a test.
5093 ## Starting application at 0x00040004 ...
5104 Hit any key to exit ...
5106 ## Application terminated, rc = 0x0
5108 Another example, which demonstrates how to register a CPM interrupt
5109 handler with the U-Boot code, can be found in 'examples/timer.c'.
5110 Here, a CPM timer is set up to generate an interrupt every second.
5111 The interrupt service routine is trivial, just printing a '.'
5112 character, but this is just a demo program. The application can be
5113 controlled by the following keys:
5115 ? - print current values og the CPM Timer registers
5116 b - enable interrupts and start timer
5117 e - stop timer and disable interrupts
5118 q - quit application
5121 ## Ready for S-Record download ...
5122 ~>examples/timer.srec
5123 1 2 3 4 5 6 7 8 9 10 11 ...
5124 [file transfer complete]
5126 ## Start Addr = 0x00040004
5129 ## Starting application at 0x00040004 ...
5132 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5135 [q, b, e, ?] Set interval 1000000 us
5138 [q, b, e, ?] ........
5139 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5142 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5145 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5148 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5150 [q, b, e, ?] ...Stopping timer
5152 [q, b, e, ?] ## Application terminated, rc = 0x0
5158 Over time, many people have reported problems when trying to use the
5159 "minicom" terminal emulation program for serial download. I (wd)
5160 consider minicom to be broken, and recommend not to use it. Under
5161 Unix, I recommend to use C-Kermit for general purpose use (and
5162 especially for kermit binary protocol download ("loadb" command), and
5163 use "cu" for S-Record download ("loads" command). See
5164 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5165 for help with kermit.
5168 Nevertheless, if you absolutely want to use it try adding this
5169 configuration to your "File transfer protocols" section:
5171 Name Program Name U/D FullScr IO-Red. Multi
5172 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5173 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5179 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5180 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5182 Building requires a cross environment; it is known to work on
5183 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5184 need gmake since the Makefiles are not compatible with BSD make).
5185 Note that the cross-powerpc package does not install include files;
5186 attempting to build U-Boot will fail because <machine/ansi.h> is
5187 missing. This file has to be installed and patched manually:
5189 # cd /usr/pkg/cross/powerpc-netbsd/include
5191 # ln -s powerpc machine
5192 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5193 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5195 Native builds *don't* work due to incompatibilities between native
5196 and U-Boot include files.
5198 Booting assumes that (the first part of) the image booted is a
5199 stage-2 loader which in turn loads and then invokes the kernel
5200 proper. Loader sources will eventually appear in the NetBSD source
5201 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5202 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5205 Implementation Internals:
5206 =========================
5208 The following is not intended to be a complete description of every
5209 implementation detail. However, it should help to understand the
5210 inner workings of U-Boot and make it easier to port it to custom
5214 Initial Stack, Global Data:
5215 ---------------------------
5217 The implementation of U-Boot is complicated by the fact that U-Boot
5218 starts running out of ROM (flash memory), usually without access to
5219 system RAM (because the memory controller is not initialized yet).
5220 This means that we don't have writable Data or BSS segments, and BSS
5221 is not initialized as zero. To be able to get a C environment working
5222 at all, we have to allocate at least a minimal stack. Implementation
5223 options for this are defined and restricted by the CPU used: Some CPU
5224 models provide on-chip memory (like the IMMR area on MPC8xx and
5225 MPC826x processors), on others (parts of) the data cache can be
5226 locked as (mis-) used as memory, etc.
5228 Chris Hallinan posted a good summary of these issues to the
5229 U-Boot mailing list:
5231 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5232 From: "Chris Hallinan" <clh@net1plus.com>
5233 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5236 Correct me if I'm wrong, folks, but the way I understand it
5237 is this: Using DCACHE as initial RAM for Stack, etc, does not
5238 require any physical RAM backing up the cache. The cleverness
5239 is that the cache is being used as a temporary supply of
5240 necessary storage before the SDRAM controller is setup. It's
5241 beyond the scope of this list to explain the details, but you
5242 can see how this works by studying the cache architecture and
5243 operation in the architecture and processor-specific manuals.
5245 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5246 is another option for the system designer to use as an
5247 initial stack/RAM area prior to SDRAM being available. Either
5248 option should work for you. Using CS 4 should be fine if your
5249 board designers haven't used it for something that would
5250 cause you grief during the initial boot! It is frequently not
5253 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5254 with your processor/board/system design. The default value
5255 you will find in any recent u-boot distribution in
5256 walnut.h should work for you. I'd set it to a value larger
5257 than your SDRAM module. If you have a 64MB SDRAM module, set
5258 it above 400_0000. Just make sure your board has no resources
5259 that are supposed to respond to that address! That code in
5260 start.S has been around a while and should work as is when
5261 you get the config right.
5266 It is essential to remember this, since it has some impact on the C
5267 code for the initialization procedures:
5269 * Initialized global data (data segment) is read-only. Do not attempt
5272 * Do not use any uninitialized global data (or implicitely initialized
5273 as zero data - BSS segment) at all - this is undefined, initiali-
5274 zation is performed later (when relocating to RAM).
5276 * Stack space is very limited. Avoid big data buffers or things like
5279 Having only the stack as writable memory limits means we cannot use
5280 normal global data to share information beween the code. But it
5281 turned out that the implementation of U-Boot can be greatly
5282 simplified by making a global data structure (gd_t) available to all
5283 functions. We could pass a pointer to this data as argument to _all_
5284 functions, but this would bloat the code. Instead we use a feature of
5285 the GCC compiler (Global Register Variables) to share the data: we
5286 place a pointer (gd) to the global data into a register which we
5287 reserve for this purpose.
5289 When choosing a register for such a purpose we are restricted by the
5290 relevant (E)ABI specifications for the current architecture, and by
5291 GCC's implementation.
5293 For PowerPC, the following registers have specific use:
5295 R2: reserved for system use
5296 R3-R4: parameter passing and return values
5297 R5-R10: parameter passing
5298 R13: small data area pointer
5302 (U-Boot also uses R12 as internal GOT pointer. r12
5303 is a volatile register so r12 needs to be reset when
5304 going back and forth between asm and C)
5306 ==> U-Boot will use R2 to hold a pointer to the global data
5308 Note: on PPC, we could use a static initializer (since the
5309 address of the global data structure is known at compile time),
5310 but it turned out that reserving a register results in somewhat
5311 smaller code - although the code savings are not that big (on
5312 average for all boards 752 bytes for the whole U-Boot image,
5313 624 text + 127 data).
5315 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5316 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5318 ==> U-Boot will use P3 to hold a pointer to the global data
5320 On ARM, the following registers are used:
5322 R0: function argument word/integer result
5323 R1-R3: function argument word
5325 R10: stack limit (used only if stack checking if enabled)
5326 R11: argument (frame) pointer
5327 R12: temporary workspace
5330 R15: program counter
5332 ==> U-Boot will use R8 to hold a pointer to the global data
5334 On Nios II, the ABI is documented here:
5335 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5337 ==> U-Boot will use gp to hold a pointer to the global data
5339 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5340 to access small data sections, so gp is free.
5342 On NDS32, the following registers are used:
5344 R0-R1: argument/return
5346 R15: temporary register for assembler
5347 R16: trampoline register
5348 R28: frame pointer (FP)
5349 R29: global pointer (GP)
5350 R30: link register (LP)
5351 R31: stack pointer (SP)
5352 PC: program counter (PC)
5354 ==> U-Boot will use R10 to hold a pointer to the global data
5356 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5357 or current versions of GCC may "optimize" the code too much.
5362 U-Boot runs in system state and uses physical addresses, i.e. the
5363 MMU is not used either for address mapping nor for memory protection.
5365 The available memory is mapped to fixed addresses using the memory
5366 controller. In this process, a contiguous block is formed for each
5367 memory type (Flash, SDRAM, SRAM), even when it consists of several
5368 physical memory banks.
5370 U-Boot is installed in the first 128 kB of the first Flash bank (on
5371 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5372 booting and sizing and initializing DRAM, the code relocates itself
5373 to the upper end of DRAM. Immediately below the U-Boot code some
5374 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5375 configuration setting]. Below that, a structure with global Board
5376 Info data is placed, followed by the stack (growing downward).
5378 Additionally, some exception handler code is copied to the low 8 kB
5379 of DRAM (0x00000000 ... 0x00001FFF).
5381 So a typical memory configuration with 16 MB of DRAM could look like
5384 0x0000 0000 Exception Vector code
5387 0x0000 2000 Free for Application Use
5393 0x00FB FF20 Monitor Stack (Growing downward)
5394 0x00FB FFAC Board Info Data and permanent copy of global data
5395 0x00FC 0000 Malloc Arena
5398 0x00FE 0000 RAM Copy of Monitor Code
5399 ... eventually: LCD or video framebuffer
5400 ... eventually: pRAM (Protected RAM - unchanged by reset)
5401 0x00FF FFFF [End of RAM]
5404 System Initialization:
5405 ----------------------
5407 In the reset configuration, U-Boot starts at the reset entry point
5408 (on most PowerPC systems at address 0x00000100). Because of the reset
5409 configuration for CS0# this is a mirror of the onboard Flash memory.
5410 To be able to re-map memory U-Boot then jumps to its link address.
5411 To be able to implement the initialization code in C, a (small!)
5412 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5413 which provide such a feature like MPC8xx or MPC8260), or in a locked
5414 part of the data cache. After that, U-Boot initializes the CPU core,
5415 the caches and the SIU.
5417 Next, all (potentially) available memory banks are mapped using a
5418 preliminary mapping. For example, we put them on 512 MB boundaries
5419 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5420 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5421 programmed for SDRAM access. Using the temporary configuration, a
5422 simple memory test is run that determines the size of the SDRAM
5425 When there is more than one SDRAM bank, and the banks are of
5426 different size, the largest is mapped first. For equal size, the first
5427 bank (CS2#) is mapped first. The first mapping is always for address
5428 0x00000000, with any additional banks following immediately to create
5429 contiguous memory starting from 0.
5431 Then, the monitor installs itself at the upper end of the SDRAM area
5432 and allocates memory for use by malloc() and for the global Board
5433 Info data; also, the exception vector code is copied to the low RAM
5434 pages, and the final stack is set up.
5436 Only after this relocation will you have a "normal" C environment;
5437 until that you are restricted in several ways, mostly because you are
5438 running from ROM, and because the code will have to be relocated to a
5442 U-Boot Porting Guide:
5443 ----------------------
5445 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5449 int main(int argc, char *argv[])
5451 sighandler_t no_more_time;
5453 signal(SIGALRM, no_more_time);
5454 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5456 if (available_money > available_manpower) {
5457 Pay consultant to port U-Boot;
5461 Download latest U-Boot source;
5463 Subscribe to u-boot mailing list;
5466 email("Hi, I am new to U-Boot, how do I get started?");
5469 Read the README file in the top level directory;
5470 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5471 Read applicable doc/*.README;
5472 Read the source, Luke;
5473 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5476 if (available_money > toLocalCurrency ($2500))
5479 Add a lot of aggravation and time;
5481 if (a similar board exists) { /* hopefully... */
5482 cp -a board/<similar> board/<myboard>
5483 cp include/configs/<similar>.h include/configs/<myboard>.h
5485 Create your own board support subdirectory;
5486 Create your own board include/configs/<myboard>.h file;
5488 Edit new board/<myboard> files
5489 Edit new include/configs/<myboard>.h
5494 Add / modify source code;
5498 email("Hi, I am having problems...");
5500 Send patch file to the U-Boot email list;
5501 if (reasonable critiques)
5502 Incorporate improvements from email list code review;
5504 Defend code as written;
5510 void no_more_time (int sig)
5519 All contributions to U-Boot should conform to the Linux kernel
5520 coding style; see the file "Documentation/CodingStyle" and the script
5521 "scripts/Lindent" in your Linux kernel source directory.
5523 Source files originating from a different project (for example the
5524 MTD subsystem) are generally exempt from these guidelines and are not
5525 reformated to ease subsequent migration to newer versions of those
5528 Please note that U-Boot is implemented in C (and to some small parts in
5529 Assembler); no C++ is used, so please do not use C++ style comments (//)
5532 Please also stick to the following formatting rules:
5533 - remove any trailing white space
5534 - use TAB characters for indentation and vertical alignment, not spaces
5535 - make sure NOT to use DOS '\r\n' line feeds
5536 - do not add more than 2 consecutive empty lines to source files
5537 - do not add trailing empty lines to source files
5539 Submissions which do not conform to the standards may be returned
5540 with a request to reformat the changes.
5546 Since the number of patches for U-Boot is growing, we need to
5547 establish some rules. Submissions which do not conform to these rules
5548 may be rejected, even when they contain important and valuable stuff.
5550 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5552 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5553 see http://lists.denx.de/mailman/listinfo/u-boot
5555 When you send a patch, please include the following information with
5558 * For bug fixes: a description of the bug and how your patch fixes
5559 this bug. Please try to include a way of demonstrating that the
5560 patch actually fixes something.
5562 * For new features: a description of the feature and your
5565 * A CHANGELOG entry as plaintext (separate from the patch)
5567 * For major contributions, your entry to the CREDITS file
5569 * When you add support for a new board, don't forget to add this
5570 board to the MAINTAINERS file, too.
5572 * If your patch adds new configuration options, don't forget to
5573 document these in the README file.
5575 * The patch itself. If you are using git (which is *strongly*
5576 recommended) you can easily generate the patch using the
5577 "git format-patch". If you then use "git send-email" to send it to
5578 the U-Boot mailing list, you will avoid most of the common problems
5579 with some other mail clients.
5581 If you cannot use git, use "diff -purN OLD NEW". If your version of
5582 diff does not support these options, then get the latest version of
5585 The current directory when running this command shall be the parent
5586 directory of the U-Boot source tree (i. e. please make sure that
5587 your patch includes sufficient directory information for the
5590 We prefer patches as plain text. MIME attachments are discouraged,
5591 and compressed attachments must not be used.
5593 * If one logical set of modifications affects or creates several
5594 files, all these changes shall be submitted in a SINGLE patch file.
5596 * Changesets that contain different, unrelated modifications shall be
5597 submitted as SEPARATE patches, one patch per changeset.
5602 * Before sending the patch, run the MAKEALL script on your patched
5603 source tree and make sure that no errors or warnings are reported
5604 for any of the boards.
5606 * Keep your modifications to the necessary minimum: A patch
5607 containing several unrelated changes or arbitrary reformats will be
5608 returned with a request to re-formatting / split it.
5610 * If you modify existing code, make sure that your new code does not
5611 add to the memory footprint of the code ;-) Small is beautiful!
5612 When adding new features, these should compile conditionally only
5613 (using #ifdef), and the resulting code with the new feature
5614 disabled must not need more memory than the old code without your
5617 * Remember that there is a size limit of 100 kB per message on the
5618 u-boot mailing list. Bigger patches will be moderated. If they are
5619 reasonable and not too big, they will be acknowledged. But patches
5620 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob