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 /mpc824x Files specific to Freescale MPC824x CPUs
205 /mpc8260 Files specific to Freescale MPC8260 CPUs
206 /mpc85xx Files specific to Freescale MPC85xx CPUs
207 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
208 /lib Architecture specific library files
209 /sh Files generic to SH architecture
210 /cpu CPU specific files
211 /sh2 Files specific to sh2 CPUs
212 /sh3 Files specific to sh3 CPUs
213 /sh4 Files specific to sh4 CPUs
214 /lib Architecture specific library files
215 /sparc Files generic to SPARC architecture
216 /cpu CPU specific files
217 /leon2 Files specific to Gaisler LEON2 SPARC CPU
218 /leon3 Files specific to Gaisler LEON3 SPARC CPU
219 /lib Architecture specific library files
220 /api Machine/arch independent API for external apps
221 /board Board dependent files
222 /common Misc architecture independent functions
223 /disk Code for disk drive partition handling
224 /doc Documentation (don't expect too much)
225 /drivers Commonly used device drivers
226 /examples Example code for standalone applications, etc.
227 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
228 /include Header Files
229 /lib Files generic to all architectures
230 /libfdt Library files to support flattened device trees
231 /lzma Library files to support LZMA decompression
232 /lzo Library files to support LZO decompression
234 /post Power On Self Test
235 /rtc Real Time Clock drivers
236 /tools Tools to build S-Record or U-Boot images, etc.
238 Software Configuration:
239 =======================
241 Configuration is usually done using C preprocessor defines; the
242 rationale behind that is to avoid dead code whenever possible.
244 There are two classes of configuration variables:
246 * Configuration _OPTIONS_:
247 These are selectable by the user and have names beginning with
250 * Configuration _SETTINGS_:
251 These depend on the hardware etc. and should not be meddled with if
252 you don't know what you're doing; they have names beginning with
255 Later we will add a configuration tool - probably similar to or even
256 identical to what's used for the Linux kernel. Right now, we have to
257 do the configuration by hand, which means creating some symbolic
258 links and editing some configuration files. We use the TQM8xxL boards
262 Selection of Processor Architecture and Board Type:
263 ---------------------------------------------------
265 For all supported boards there are ready-to-use default
266 configurations available; just type "make <board_name>_config".
268 Example: For a TQM823L module type:
273 For the Cogent platform, you need to specify the CPU type as well;
274 e.g. "make cogent_mpc8xx_config". And also configure the cogent
275 directory according to the instructions in cogent/README.
278 Configuration Options:
279 ----------------------
281 Configuration depends on the combination of board and CPU type; all
282 such information is kept in a configuration file
283 "include/configs/<board_name>.h".
285 Example: For a TQM823L module, all configuration settings are in
286 "include/configs/TQM823L.h".
289 Many of the options are named exactly as the corresponding Linux
290 kernel configuration options. The intention is to make it easier to
291 build a config tool - later.
294 The following options need to be configured:
296 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
298 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
300 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
301 Define exactly one, e.g. CONFIG_ATSTK1002
303 - CPU Module Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
306 --- FIXME --- not tested yet:
307 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
308 CONFIG_CMA287_23, CONFIG_CMA287_50
310 - Motherboard Type: (if CONFIG_COGENT is defined)
311 Define exactly one of
312 CONFIG_CMA101, CONFIG_CMA102
314 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
315 Define one or more of
318 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
319 Define one or more of
320 CONFIG_LCD_HEARTBEAT - update a character position on
321 the LCD display every second with
324 - Board flavour: (if CONFIG_MPC8260ADS is defined)
327 CONFIG_SYS_8260ADS - original MPC8260ADS
328 CONFIG_SYS_8266ADS - MPC8266ADS
329 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
330 CONFIG_SYS_8272ADS - MPC8272ADS
332 - Marvell Family Member
333 CONFIG_SYS_MVFS - define it if you want to enable
334 multiple fs option at one time
335 for marvell soc family
337 - MPC824X Family Member (if CONFIG_MPC824X is defined)
338 Define exactly one of
339 CONFIG_MPC8240, CONFIG_MPC8245
341 - 8xx CPU Options: (if using an MPC8xx CPU)
342 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
343 get_gclk_freq() cannot work
344 e.g. if there is no 32KHz
345 reference PIT/RTC clock
346 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
349 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
350 CONFIG_SYS_8xx_CPUCLK_MIN
351 CONFIG_SYS_8xx_CPUCLK_MAX
352 CONFIG_8xx_CPUCLK_DEFAULT
353 See doc/README.MPC866
355 CONFIG_SYS_MEASURE_CPUCLK
357 Define this to measure the actual CPU clock instead
358 of relying on the correctness of the configured
359 values. Mostly useful for board bringup to make sure
360 the PLL is locked at the intended frequency. Note
361 that this requires a (stable) reference clock (32 kHz
362 RTC clock or CONFIG_SYS_8XX_XIN)
364 CONFIG_SYS_DELAYED_ICACHE
366 Define this option if you want to enable the
367 ICache only when Code runs from RAM.
372 Specifies that the core is a 64-bit PowerPC implementation (implements
373 the "64" category of the Power ISA). This is necessary for ePAPR
374 compliance, among other possible reasons.
376 CONFIG_SYS_FSL_TBCLK_DIV
378 Defines the core time base clock divider ratio compared to the
379 system clock. On most PQ3 devices this is 8, on newer QorIQ
380 devices it can be 16 or 32. The ratio varies from SoC to Soc.
382 CONFIG_SYS_FSL_PCIE_COMPAT
384 Defines the string to utilize when trying to match PCIe device
385 tree nodes for the given platform.
387 CONFIG_SYS_PPC_E500_DEBUG_TLB
389 Enables a temporary TLB entry to be used during boot to work
390 around limitations in e500v1 and e500v2 external debugger
391 support. This reduces the portions of the boot code where
392 breakpoints and single stepping do not work. The value of this
393 symbol should be set to the TLB1 entry to be used for this
396 CONFIG_SYS_FSL_ERRATUM_A004510
398 Enables a workaround for erratum A004510. If set,
399 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
400 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
402 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
403 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
405 Defines one or two SoC revisions (low 8 bits of SVR)
406 for which the A004510 workaround should be applied.
408 The rest of SVR is either not relevant to the decision
409 of whether the erratum is present (e.g. p2040 versus
410 p2041) or is implied by the build target, which controls
411 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
413 See Freescale App Note 4493 for more information about
416 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
418 This is the value to write into CCSR offset 0x18600
419 according to the A004510 workaround.
421 - Generic CPU options:
422 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
424 Defines the endianess of the CPU. Implementation of those
425 values is arch specific.
427 - Intel Monahans options:
428 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
430 Defines the Monahans run mode to oscillator
431 ratio. Valid values are 8, 16, 24, 31. The core
432 frequency is this value multiplied by 13 MHz.
434 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
436 Defines the Monahans turbo mode to oscillator
437 ratio. Valid values are 1 (default if undefined) and
438 2. The core frequency as calculated above is multiplied
442 CONFIG_SYS_INIT_SP_OFFSET
444 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
445 pointer. This is needed for the temporary stack before
448 CONFIG_SYS_MIPS_CACHE_MODE
450 Cache operation mode for the MIPS CPU.
451 See also arch/mips/include/asm/mipsregs.h.
453 CONF_CM_CACHABLE_NO_WA
456 CONF_CM_CACHABLE_NONCOHERENT
460 CONF_CM_CACHABLE_ACCELERATED
462 CONFIG_SYS_XWAY_EBU_BOOTCFG
464 Special option for Lantiq XWAY SoCs for booting from NOR flash.
465 See also arch/mips/cpu/mips32/start.S.
467 CONFIG_XWAY_SWAP_BYTES
469 Enable compilation of tools/xway-swap-bytes needed for Lantiq
470 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
471 be swapped if a flash programmer is used.
474 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
476 Select high exception vectors of the ARM core, e.g., do not
477 clear the V bit of the c1 register of CP15.
479 CONFIG_SYS_THUMB_BUILD
481 Use this flag to build U-Boot using the Thumb instruction
482 set for ARM architectures. Thumb instruction set provides
483 better code density. For ARM architectures that support
484 Thumb2 this flag will result in Thumb2 code generated by
487 CONFIG_ARM_ERRATA_716044
488 CONFIG_ARM_ERRATA_742230
489 CONFIG_ARM_ERRATA_743622
490 CONFIG_ARM_ERRATA_751472
492 If set, the workarounds for these ARM errata are applied early
493 during U-Boot startup. Note that these options force the
494 workarounds to be applied; no CPU-type/version detection
495 exists, unlike the similar options in the Linux kernel. Do not
496 set these options unless they apply!
501 The frequency of the timer returned by get_timer().
502 get_timer() must operate in milliseconds and this CONFIG
503 option must be set to 1000.
505 - Linux Kernel Interface:
508 U-Boot stores all clock information in Hz
509 internally. For binary compatibility with older Linux
510 kernels (which expect the clocks passed in the
511 bd_info data to be in MHz) the environment variable
512 "clocks_in_mhz" can be defined so that U-Boot
513 converts clock data to MHZ before passing it to the
515 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
516 "clocks_in_mhz=1" is automatically included in the
519 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
521 When transferring memsize parameter to linux, some versions
522 expect it to be in bytes, others in MB.
523 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
527 New kernel versions are expecting firmware settings to be
528 passed using flattened device trees (based on open firmware
532 * New libfdt-based support
533 * Adds the "fdt" command
534 * The bootm command automatically updates the fdt
536 OF_CPU - The proper name of the cpus node (only required for
537 MPC512X and MPC5xxx based boards).
538 OF_SOC - The proper name of the soc node (only required for
539 MPC512X and MPC5xxx based boards).
540 OF_TBCLK - The timebase frequency.
541 OF_STDOUT_PATH - The path to the console device
543 boards with QUICC Engines require OF_QE to set UCC MAC
546 CONFIG_OF_BOARD_SETUP
548 Board code has addition modification that it wants to make
549 to the flat device tree before handing it off to the kernel
553 This define fills in the correct boot CPU in the boot
554 param header, the default value is zero if undefined.
558 U-Boot can detect if an IDE device is present or not.
559 If not, and this new config option is activated, U-Boot
560 removes the ATA node from the DTS before booting Linux,
561 so the Linux IDE driver does not probe the device and
562 crash. This is needed for buggy hardware (uc101) where
563 no pull down resistor is connected to the signal IDE5V_DD7.
565 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
567 This setting is mandatory for all boards that have only one
568 machine type and must be used to specify the machine type
569 number as it appears in the ARM machine registry
570 (see http://www.arm.linux.org.uk/developer/machines/).
571 Only boards that have multiple machine types supported
572 in a single configuration file and the machine type is
573 runtime discoverable, do not have to use this setting.
575 - vxWorks boot parameters:
577 bootvx constructs a valid bootline using the following
578 environments variables: bootfile, ipaddr, serverip, hostname.
579 It loads the vxWorks image pointed bootfile.
581 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
582 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
583 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
584 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
586 CONFIG_SYS_VXWORKS_ADD_PARAMS
588 Add it at the end of the bootline. E.g "u=username pw=secret"
590 Note: If a "bootargs" environment is defined, it will overwride
591 the defaults discussed just above.
593 - Cache Configuration:
594 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
595 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
596 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
598 - Cache Configuration for ARM:
599 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
601 CONFIG_SYS_PL310_BASE - Physical base address of PL310
602 controller register space
607 Define this if you want support for Amba PrimeCell PL010 UARTs.
611 Define this if you want support for Amba PrimeCell PL011 UARTs.
615 If you have Amba PrimeCell PL011 UARTs, set this variable to
616 the clock speed of the UARTs.
620 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
621 define this to a list of base addresses for each (supported)
622 port. See e.g. include/configs/versatile.h
624 CONFIG_PL011_SERIAL_RLCR
626 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
627 have separate receive and transmit line control registers. Set
628 this variable to initialize the extra register.
630 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
632 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
633 boot loader that has already initialized the UART. Define this
634 variable to flush the UART at init time.
638 Depending on board, define exactly one serial port
639 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
640 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
641 console by defining CONFIG_8xx_CONS_NONE
643 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
644 port routines must be defined elsewhere
645 (i.e. serial_init(), serial_getc(), ...)
648 Enables console device for a color framebuffer. Needs following
649 defines (cf. smiLynxEM, i8042)
650 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
652 VIDEO_HW_RECTFILL graphic chip supports
655 VIDEO_HW_BITBLT graphic chip supports
656 bit-blit (cf. smiLynxEM)
657 VIDEO_VISIBLE_COLS visible pixel columns
659 VIDEO_VISIBLE_ROWS visible pixel rows
660 VIDEO_PIXEL_SIZE bytes per pixel
661 VIDEO_DATA_FORMAT graphic data format
662 (0-5, cf. cfb_console.c)
663 VIDEO_FB_ADRS framebuffer address
664 VIDEO_KBD_INIT_FCT keyboard int fct
665 (i.e. i8042_kbd_init())
666 VIDEO_TSTC_FCT test char fct
668 VIDEO_GETC_FCT get char fct
670 CONFIG_CONSOLE_CURSOR cursor drawing on/off
671 (requires blink timer
673 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
674 CONFIG_CONSOLE_TIME display time/date info in
676 (requires CONFIG_CMD_DATE)
677 CONFIG_VIDEO_LOGO display Linux logo in
679 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
680 linux_logo.h for logo.
681 Requires CONFIG_VIDEO_LOGO
682 CONFIG_CONSOLE_EXTRA_INFO
683 additional board info beside
686 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
687 a limited number of ANSI escape sequences (cursor control,
688 erase functions and limited graphics rendition control).
690 When CONFIG_CFB_CONSOLE is defined, video console is
691 default i/o. Serial console can be forced with
692 environment 'console=serial'.
694 When CONFIG_SILENT_CONSOLE is defined, all console
695 messages (by U-Boot and Linux!) can be silenced with
696 the "silent" environment variable. See
697 doc/README.silent for more information.
700 CONFIG_BAUDRATE - in bps
701 Select one of the baudrates listed in
702 CONFIG_SYS_BAUDRATE_TABLE, see below.
703 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
705 - Console Rx buffer length
706 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
707 the maximum receive buffer length for the SMC.
708 This option is actual only for 82xx and 8xx possible.
709 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
710 must be defined, to setup the maximum idle timeout for
713 - Pre-Console Buffer:
714 Prior to the console being initialised (i.e. serial UART
715 initialised etc) all console output is silently discarded.
716 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
717 buffer any console messages prior to the console being
718 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
719 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
720 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
721 bytes are output before the console is initialised, the
722 earlier bytes are discarded.
724 'Sane' compilers will generate smaller code if
725 CONFIG_PRE_CON_BUF_SZ is a power of 2
727 - Safe printf() functions
728 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
729 the printf() functions. These are defined in
730 include/vsprintf.h and include snprintf(), vsnprintf() and
731 so on. Code size increase is approximately 300-500 bytes.
732 If this option is not given then these functions will
733 silently discard their buffer size argument - this means
734 you are not getting any overflow checking in this case.
736 - Boot Delay: CONFIG_BOOTDELAY - in seconds
737 Delay before automatically booting the default image;
738 set to -1 to disable autoboot.
739 set to -2 to autoboot with no delay and not check for abort
740 (even when CONFIG_ZERO_BOOTDELAY_CHECK is defined).
742 See doc/README.autoboot for these options that
743 work with CONFIG_BOOTDELAY. None are required.
744 CONFIG_BOOT_RETRY_TIME
745 CONFIG_BOOT_RETRY_MIN
746 CONFIG_AUTOBOOT_KEYED
747 CONFIG_AUTOBOOT_PROMPT
748 CONFIG_AUTOBOOT_DELAY_STR
749 CONFIG_AUTOBOOT_STOP_STR
750 CONFIG_AUTOBOOT_DELAY_STR2
751 CONFIG_AUTOBOOT_STOP_STR2
752 CONFIG_ZERO_BOOTDELAY_CHECK
753 CONFIG_RESET_TO_RETRY
757 Only needed when CONFIG_BOOTDELAY is enabled;
758 define a command string that is automatically executed
759 when no character is read on the console interface
760 within "Boot Delay" after reset.
763 This can be used to pass arguments to the bootm
764 command. The value of CONFIG_BOOTARGS goes into the
765 environment value "bootargs".
767 CONFIG_RAMBOOT and CONFIG_NFSBOOT
768 The value of these goes into the environment as
769 "ramboot" and "nfsboot" respectively, and can be used
770 as a convenience, when switching between booting from
776 When this option is #defined, the existence of the
777 environment variable "preboot" will be checked
778 immediately before starting the CONFIG_BOOTDELAY
779 countdown and/or running the auto-boot command resp.
780 entering interactive mode.
782 This feature is especially useful when "preboot" is
783 automatically generated or modified. For an example
784 see the LWMON board specific code: here "preboot" is
785 modified when the user holds down a certain
786 combination of keys on the (special) keyboard when
789 - Serial Download Echo Mode:
791 If defined to 1, all characters received during a
792 serial download (using the "loads" command) are
793 echoed back. This might be needed by some terminal
794 emulations (like "cu"), but may as well just take
795 time on others. This setting #define's the initial
796 value of the "loads_echo" environment variable.
798 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
800 Select one of the baudrates listed in
801 CONFIG_SYS_BAUDRATE_TABLE, see below.
804 Monitor commands can be included or excluded
805 from the build by using the #include files
806 <config_cmd_all.h> and #undef'ing unwanted
807 commands, or using <config_cmd_default.h>
808 and augmenting with additional #define's
811 The default command configuration includes all commands
812 except those marked below with a "*".
814 CONFIG_CMD_ASKENV * ask for env variable
815 CONFIG_CMD_BDI bdinfo
816 CONFIG_CMD_BEDBUG * Include BedBug Debugger
817 CONFIG_CMD_BMP * BMP support
818 CONFIG_CMD_BSP * Board specific commands
819 CONFIG_CMD_BOOTD bootd
820 CONFIG_CMD_CACHE * icache, dcache
821 CONFIG_CMD_CONSOLE coninfo
822 CONFIG_CMD_CRC32 * crc32
823 CONFIG_CMD_DATE * support for RTC, date/time...
824 CONFIG_CMD_DHCP * DHCP support
825 CONFIG_CMD_DIAG * Diagnostics
826 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
827 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
828 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
829 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
830 CONFIG_CMD_DTT * Digital Therm and Thermostat
831 CONFIG_CMD_ECHO echo arguments
832 CONFIG_CMD_EDITENV edit env variable
833 CONFIG_CMD_EEPROM * EEPROM read/write support
834 CONFIG_CMD_ELF * bootelf, bootvx
835 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
836 CONFIG_CMD_ENV_FLAGS * display details about env flags
837 CONFIG_CMD_EXPORTENV * export the environment
838 CONFIG_CMD_EXT2 * ext2 command support
839 CONFIG_CMD_EXT4 * ext4 command support
840 CONFIG_CMD_SAVEENV saveenv
841 CONFIG_CMD_FDC * Floppy Disk Support
842 CONFIG_CMD_FAT * FAT command support
843 CONFIG_CMD_FDOS * Dos diskette Support
844 CONFIG_CMD_FLASH flinfo, erase, protect
845 CONFIG_CMD_FPGA FPGA device initialization support
846 CONFIG_CMD_GETTIME * Get time since boot
847 CONFIG_CMD_GO * the 'go' command (exec code)
848 CONFIG_CMD_GREPENV * search environment
849 CONFIG_CMD_HASH * calculate hash / digest
850 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
851 CONFIG_CMD_I2C * I2C serial bus support
852 CONFIG_CMD_IDE * IDE harddisk support
853 CONFIG_CMD_IMI iminfo
854 CONFIG_CMD_IMLS List all images found in NOR flash
855 CONFIG_CMD_IMLS_NAND List all images found in NAND flash
856 CONFIG_CMD_IMMAP * IMMR dump support
857 CONFIG_CMD_IMPORTENV * import an environment
858 CONFIG_CMD_INI * import data from an ini file into the env
859 CONFIG_CMD_IRQ * irqinfo
860 CONFIG_CMD_ITEST Integer/string test of 2 values
861 CONFIG_CMD_JFFS2 * JFFS2 Support
862 CONFIG_CMD_KGDB * kgdb
863 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
864 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
866 CONFIG_CMD_LOADB loadb
867 CONFIG_CMD_LOADS loads
868 CONFIG_CMD_MD5SUM print md5 message digest
869 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
870 CONFIG_CMD_MEMINFO * Display detailed memory information
871 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
873 CONFIG_CMD_MEMTEST mtest
874 CONFIG_CMD_MISC Misc functions like sleep etc
875 CONFIG_CMD_MMC * MMC memory mapped support
876 CONFIG_CMD_MII * MII utility commands
877 CONFIG_CMD_MTDPARTS * MTD partition support
878 CONFIG_CMD_NAND * NAND support
879 CONFIG_CMD_NET bootp, tftpboot, rarpboot
880 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
881 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
882 CONFIG_CMD_PCI * pciinfo
883 CONFIG_CMD_PCMCIA * PCMCIA support
884 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
886 CONFIG_CMD_PORTIO * Port I/O
887 CONFIG_CMD_READ * Read raw data from partition
888 CONFIG_CMD_REGINFO * Register dump
889 CONFIG_CMD_RUN run command in env variable
890 CONFIG_CMD_SANDBOX * sb command to access sandbox features
891 CONFIG_CMD_SAVES * save S record dump
892 CONFIG_CMD_SCSI * SCSI Support
893 CONFIG_CMD_SDRAM * print SDRAM configuration information
894 (requires CONFIG_CMD_I2C)
895 CONFIG_CMD_SETGETDCR Support for DCR Register access
897 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
898 CONFIG_CMD_SHA1SUM print sha1 memory digest
899 (requires CONFIG_CMD_MEMORY)
900 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
901 CONFIG_CMD_SOURCE "source" command Support
902 CONFIG_CMD_SPI * SPI serial bus support
903 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
904 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
905 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
906 CONFIG_CMD_TIMER * access to the system tick timer
907 CONFIG_CMD_USB * USB support
908 CONFIG_CMD_CDP * Cisco Discover Protocol support
909 CONFIG_CMD_MFSL * Microblaze FSL support
912 EXAMPLE: If you want all functions except of network
913 support you can write:
915 #include "config_cmd_all.h"
916 #undef CONFIG_CMD_NET
919 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
921 Note: Don't enable the "icache" and "dcache" commands
922 (configuration option CONFIG_CMD_CACHE) unless you know
923 what you (and your U-Boot users) are doing. Data
924 cache cannot be enabled on systems like the 8xx or
925 8260 (where accesses to the IMMR region must be
926 uncached), and it cannot be disabled on all other
927 systems where we (mis-) use the data cache to hold an
928 initial stack and some data.
931 XXX - this list needs to get updated!
933 - Regular expression support:
935 If this variable is defined, U-Boot is linked against
936 the SLRE (Super Light Regular Expression) library,
937 which adds regex support to some commands, as for
938 example "env grep" and "setexpr".
942 If this variable is defined, U-Boot will use a device tree
943 to configure its devices, instead of relying on statically
944 compiled #defines in the board file. This option is
945 experimental and only available on a few boards. The device
946 tree is available in the global data as gd->fdt_blob.
948 U-Boot needs to get its device tree from somewhere. This can
949 be done using one of the two options below:
952 If this variable is defined, U-Boot will embed a device tree
953 binary in its image. This device tree file should be in the
954 board directory and called <soc>-<board>.dts. The binary file
955 is then picked up in board_init_f() and made available through
956 the global data structure as gd->blob.
959 If this variable is defined, U-Boot will build a device tree
960 binary. It will be called u-boot.dtb. Architecture-specific
961 code will locate it at run-time. Generally this works by:
963 cat u-boot.bin u-boot.dtb >image.bin
965 and in fact, U-Boot does this for you, creating a file called
966 u-boot-dtb.bin which is useful in the common case. You can
967 still use the individual files if you need something more
972 If this variable is defined, it enables watchdog
973 support for the SoC. There must be support in the SoC
974 specific code for a watchdog. For the 8xx and 8260
975 CPUs, the SIU Watchdog feature is enabled in the SYPCR
976 register. When supported for a specific SoC is
977 available, then no further board specific code should
981 When using a watchdog circuitry external to the used
982 SoC, then define this variable and provide board
983 specific code for the "hw_watchdog_reset" function.
986 CONFIG_VERSION_VARIABLE
987 If this variable is defined, an environment variable
988 named "ver" is created by U-Boot showing the U-Boot
989 version as printed by the "version" command.
990 Any change to this variable will be reverted at the
995 When CONFIG_CMD_DATE is selected, the type of the RTC
996 has to be selected, too. Define exactly one of the
999 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1000 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1001 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1002 CONFIG_RTC_MC146818 - use MC146818 RTC
1003 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1004 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1005 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1006 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1007 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1008 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1009 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1010 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1013 Note that if the RTC uses I2C, then the I2C interface
1014 must also be configured. See I2C Support, below.
1017 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1018 CONFIG_PCA953X_INFO - enable pca953x info command
1020 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1021 chip-ngpio pairs that tell the PCA953X driver the number of
1022 pins supported by a particular chip.
1024 Note that if the GPIO device uses I2C, then the I2C interface
1025 must also be configured. See I2C Support, below.
1027 - Timestamp Support:
1029 When CONFIG_TIMESTAMP is selected, the timestamp
1030 (date and time) of an image is printed by image
1031 commands like bootm or iminfo. This option is
1032 automatically enabled when you select CONFIG_CMD_DATE .
1034 - Partition Labels (disklabels) Supported:
1035 Zero or more of the following:
1036 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1037 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1038 Intel architecture, USB sticks, etc.
1039 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1040 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1041 bootloader. Note 2TB partition limit; see
1043 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1045 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1046 CONFIG_CMD_SCSI) you must configure support for at
1047 least one non-MTD partition type as well.
1050 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1051 board configurations files but used nowhere!
1053 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1054 be performed by calling the function
1055 ide_set_reset(int reset)
1056 which has to be defined in a board specific file
1061 Set this to enable ATAPI support.
1066 Set this to enable support for disks larger than 137GB
1067 Also look at CONFIG_SYS_64BIT_LBA.
1068 Whithout these , LBA48 support uses 32bit variables and will 'only'
1069 support disks up to 2.1TB.
1071 CONFIG_SYS_64BIT_LBA:
1072 When enabled, makes the IDE subsystem use 64bit sector addresses.
1076 At the moment only there is only support for the
1077 SYM53C8XX SCSI controller; define
1078 CONFIG_SCSI_SYM53C8XX to enable it.
1080 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1081 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1082 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1083 maximum numbers of LUNs, SCSI ID's and target
1085 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1087 The environment variable 'scsidevs' is set to the number of
1088 SCSI devices found during the last scan.
1090 - NETWORK Support (PCI):
1092 Support for Intel 8254x/8257x gigabit chips.
1095 Utility code for direct access to the SPI bus on Intel 8257x.
1096 This does not do anything useful unless you set at least one
1097 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1099 CONFIG_E1000_SPI_GENERIC
1100 Allow generic access to the SPI bus on the Intel 8257x, for
1101 example with the "sspi" command.
1104 Management command for E1000 devices. When used on devices
1105 with SPI support you can reprogram the EEPROM from U-Boot.
1107 CONFIG_E1000_FALLBACK_MAC
1108 default MAC for empty EEPROM after production.
1111 Support for Intel 82557/82559/82559ER chips.
1112 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1113 write routine for first time initialisation.
1116 Support for Digital 2114x chips.
1117 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1118 modem chip initialisation (KS8761/QS6611).
1121 Support for National dp83815 chips.
1124 Support for National dp8382[01] gigabit chips.
1126 - NETWORK Support (other):
1128 CONFIG_DRIVER_AT91EMAC
1129 Support for AT91RM9200 EMAC.
1132 Define this to use reduced MII inteface
1134 CONFIG_DRIVER_AT91EMAC_QUIET
1135 If this defined, the driver is quiet.
1136 The driver doen't show link status messages.
1138 CONFIG_CALXEDA_XGMAC
1139 Support for the Calxeda XGMAC device
1142 Support for SMSC's LAN91C96 chips.
1144 CONFIG_LAN91C96_BASE
1145 Define this to hold the physical address
1146 of the LAN91C96's I/O space
1148 CONFIG_LAN91C96_USE_32_BIT
1149 Define this to enable 32 bit addressing
1152 Support for SMSC's LAN91C111 chip
1154 CONFIG_SMC91111_BASE
1155 Define this to hold the physical address
1156 of the device (I/O space)
1158 CONFIG_SMC_USE_32_BIT
1159 Define this if data bus is 32 bits
1161 CONFIG_SMC_USE_IOFUNCS
1162 Define this to use i/o functions instead of macros
1163 (some hardware wont work with macros)
1165 CONFIG_DRIVER_TI_EMAC
1166 Support for davinci emac
1168 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1169 Define this if you have more then 3 PHYs.
1172 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1174 CONFIG_FTGMAC100_EGIGA
1175 Define this to use GE link update with gigabit PHY.
1176 Define this if FTGMAC100 is connected to gigabit PHY.
1177 If your system has 10/100 PHY only, it might not occur
1178 wrong behavior. Because PHY usually return timeout or
1179 useless data when polling gigabit status and gigabit
1180 control registers. This behavior won't affect the
1181 correctnessof 10/100 link speed update.
1184 Support for SMSC's LAN911x and LAN921x chips
1187 Define this to hold the physical address
1188 of the device (I/O space)
1190 CONFIG_SMC911X_32_BIT
1191 Define this if data bus is 32 bits
1193 CONFIG_SMC911X_16_BIT
1194 Define this if data bus is 16 bits. If your processor
1195 automatically converts one 32 bit word to two 16 bit
1196 words you may also try CONFIG_SMC911X_32_BIT.
1199 Support for Renesas on-chip Ethernet controller
1201 CONFIG_SH_ETHER_USE_PORT
1202 Define the number of ports to be used
1204 CONFIG_SH_ETHER_PHY_ADDR
1205 Define the ETH PHY's address
1207 CONFIG_SH_ETHER_CACHE_WRITEBACK
1208 If this option is set, the driver enables cache flush.
1211 CONFIG_GENERIC_LPC_TPM
1212 Support for generic parallel port TPM devices. Only one device
1213 per system is supported at this time.
1215 CONFIG_TPM_TIS_BASE_ADDRESS
1216 Base address where the generic TPM device is mapped
1217 to. Contemporary x86 systems usually map it at
1221 At the moment only the UHCI host controller is
1222 supported (PIP405, MIP405, MPC5200); define
1223 CONFIG_USB_UHCI to enable it.
1224 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1225 and define CONFIG_USB_STORAGE to enable the USB
1228 Supported are USB Keyboards and USB Floppy drives
1230 MPC5200 USB requires additional defines:
1232 for 528 MHz Clock: 0x0001bbbb
1236 for differential drivers: 0x00001000
1237 for single ended drivers: 0x00005000
1238 for differential drivers on PSC3: 0x00000100
1239 for single ended drivers on PSC3: 0x00004100
1240 CONFIG_SYS_USB_EVENT_POLL
1241 May be defined to allow interrupt polling
1242 instead of using asynchronous interrupts
1244 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1245 txfilltuning field in the EHCI controller on reset.
1248 Define the below if you wish to use the USB console.
1249 Once firmware is rebuilt from a serial console issue the
1250 command "setenv stdin usbtty; setenv stdout usbtty" and
1251 attach your USB cable. The Unix command "dmesg" should print
1252 it has found a new device. The environment variable usbtty
1253 can be set to gserial or cdc_acm to enable your device to
1254 appear to a USB host as a Linux gserial device or a
1255 Common Device Class Abstract Control Model serial device.
1256 If you select usbtty = gserial you should be able to enumerate
1258 # modprobe usbserial vendor=0xVendorID product=0xProductID
1259 else if using cdc_acm, simply setting the environment
1260 variable usbtty to be cdc_acm should suffice. The following
1261 might be defined in YourBoardName.h
1264 Define this to build a UDC device
1267 Define this to have a tty type of device available to
1268 talk to the UDC device
1271 Define this to enable the high speed support for usb
1272 device and usbtty. If this feature is enabled, a routine
1273 int is_usbd_high_speed(void)
1274 also needs to be defined by the driver to dynamically poll
1275 whether the enumeration has succeded at high speed or full
1278 CONFIG_SYS_CONSOLE_IS_IN_ENV
1279 Define this if you want stdin, stdout &/or stderr to
1283 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1284 Derive USB clock from external clock "blah"
1285 - CONFIG_SYS_USB_EXTC_CLK 0x02
1287 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1288 Derive USB clock from brgclk
1289 - CONFIG_SYS_USB_BRG_CLK 0x04
1291 If you have a USB-IF assigned VendorID then you may wish to
1292 define your own vendor specific values either in BoardName.h
1293 or directly in usbd_vendor_info.h. If you don't define
1294 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1295 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1296 should pretend to be a Linux device to it's target host.
1298 CONFIG_USBD_MANUFACTURER
1299 Define this string as the name of your company for
1300 - CONFIG_USBD_MANUFACTURER "my company"
1302 CONFIG_USBD_PRODUCT_NAME
1303 Define this string as the name of your product
1304 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1306 CONFIG_USBD_VENDORID
1307 Define this as your assigned Vendor ID from the USB
1308 Implementors Forum. This *must* be a genuine Vendor ID
1309 to avoid polluting the USB namespace.
1310 - CONFIG_USBD_VENDORID 0xFFFF
1312 CONFIG_USBD_PRODUCTID
1313 Define this as the unique Product ID
1315 - CONFIG_USBD_PRODUCTID 0xFFFF
1317 - ULPI Layer Support:
1318 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1319 the generic ULPI layer. The generic layer accesses the ULPI PHY
1320 via the platform viewport, so you need both the genric layer and
1321 the viewport enabled. Currently only Chipidea/ARC based
1322 viewport is supported.
1323 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1324 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1325 If your ULPI phy needs a different reference clock than the
1326 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1327 the appropriate value in Hz.
1330 The MMC controller on the Intel PXA is supported. To
1331 enable this define CONFIG_MMC. The MMC can be
1332 accessed from the boot prompt by mapping the device
1333 to physical memory similar to flash. Command line is
1334 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1335 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1338 Support for Renesas on-chip MMCIF controller
1340 CONFIG_SH_MMCIF_ADDR
1341 Define the base address of MMCIF registers
1344 Define the clock frequency for MMCIF
1346 - USB Device Firmware Update (DFU) class support:
1348 This enables the USB portion of the DFU USB class
1351 This enables the command "dfu" which is used to have
1352 U-Boot create a DFU class device via USB. This command
1353 requires that the "dfu_alt_info" environment variable be
1354 set and define the alt settings to expose to the host.
1357 This enables support for exposing (e)MMC devices via DFU.
1360 This enables support for exposing NAND devices via DFU.
1362 CONFIG_SYS_DFU_MAX_FILE_SIZE
1363 When updating files rather than the raw storage device,
1364 we use a static buffer to copy the file into and then write
1365 the buffer once we've been given the whole file. Define
1366 this to the maximum filesize (in bytes) for the buffer.
1367 Default is 4 MiB if undefined.
1369 - Journaling Flash filesystem support:
1370 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1371 CONFIG_JFFS2_NAND_DEV
1372 Define these for a default partition on a NAND device
1374 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1375 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1376 Define these for a default partition on a NOR device
1378 CONFIG_SYS_JFFS_CUSTOM_PART
1379 Define this to create an own partition. You have to provide a
1380 function struct part_info* jffs2_part_info(int part_num)
1382 If you define only one JFFS2 partition you may also want to
1383 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1384 to disable the command chpart. This is the default when you
1385 have not defined a custom partition
1387 - FAT(File Allocation Table) filesystem write function support:
1390 Define this to enable support for saving memory data as a
1391 file in FAT formatted partition.
1393 This will also enable the command "fatwrite" enabling the
1394 user to write files to FAT.
1396 CBFS (Coreboot Filesystem) support
1399 Define this to enable support for reading from a Coreboot
1400 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1406 Define this to enable standard (PC-Style) keyboard
1410 Standard PC keyboard driver with US (is default) and
1411 GERMAN key layout (switch via environment 'keymap=de') support.
1412 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1413 for cfb_console. Supports cursor blinking.
1418 Define this to enable video support (for output to
1421 CONFIG_VIDEO_CT69000
1423 Enable Chips & Technologies 69000 Video chip
1425 CONFIG_VIDEO_SMI_LYNXEM
1426 Enable Silicon Motion SMI 712/710/810 Video chip. The
1427 video output is selected via environment 'videoout'
1428 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1431 For the CT69000 and SMI_LYNXEM drivers, videomode is
1432 selected via environment 'videomode'. Two different ways
1434 - "videomode=num" 'num' is a standard LiLo mode numbers.
1435 Following standard modes are supported (* is default):
1437 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1438 -------------+---------------------------------------------
1439 8 bits | 0x301* 0x303 0x305 0x161 0x307
1440 15 bits | 0x310 0x313 0x316 0x162 0x319
1441 16 bits | 0x311 0x314 0x317 0x163 0x31A
1442 24 bits | 0x312 0x315 0x318 ? 0x31B
1443 -------------+---------------------------------------------
1444 (i.e. setenv videomode 317; saveenv; reset;)
1446 - "videomode=bootargs" all the video parameters are parsed
1447 from the bootargs. (See drivers/video/videomodes.c)
1450 CONFIG_VIDEO_SED13806
1451 Enable Epson SED13806 driver. This driver supports 8bpp
1452 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1453 or CONFIG_VIDEO_SED13806_16BPP
1456 Enable the Freescale DIU video driver. Reference boards for
1457 SOCs that have a DIU should define this macro to enable DIU
1458 support, and should also define these other macros:
1464 CONFIG_VIDEO_SW_CURSOR
1465 CONFIG_VGA_AS_SINGLE_DEVICE
1467 CONFIG_VIDEO_BMP_LOGO
1469 The DIU driver will look for the 'video-mode' environment
1470 variable, and if defined, enable the DIU as a console during
1471 boot. See the documentation file README.video for a
1472 description of this variable.
1476 Enable the VGA video / BIOS for x86. The alternative if you
1477 are using coreboot is to use the coreboot frame buffer
1484 Define this to enable a custom keyboard support.
1485 This simply calls drv_keyboard_init() which must be
1486 defined in your board-specific files.
1487 The only board using this so far is RBC823.
1489 - LCD Support: CONFIG_LCD
1491 Define this to enable LCD support (for output to LCD
1492 display); also select one of the supported displays
1493 by defining one of these:
1497 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1499 CONFIG_NEC_NL6448AC33:
1501 NEC NL6448AC33-18. Active, color, single scan.
1503 CONFIG_NEC_NL6448BC20
1505 NEC NL6448BC20-08. 6.5", 640x480.
1506 Active, color, single scan.
1508 CONFIG_NEC_NL6448BC33_54
1510 NEC NL6448BC33-54. 10.4", 640x480.
1511 Active, color, single scan.
1515 Sharp 320x240. Active, color, single scan.
1516 It isn't 16x9, and I am not sure what it is.
1518 CONFIG_SHARP_LQ64D341
1520 Sharp LQ64D341 display, 640x480.
1521 Active, color, single scan.
1525 HLD1045 display, 640x480.
1526 Active, color, single scan.
1530 Optrex CBL50840-2 NF-FW 99 22 M5
1532 Hitachi LMG6912RPFC-00T
1536 320x240. Black & white.
1538 Normally display is black on white background; define
1539 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1541 CONFIG_LCD_ALIGNMENT
1543 Normally the LCD is page-aligned (tyically 4KB). If this is
1544 defined then the LCD will be aligned to this value instead.
1545 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1546 here, since it is cheaper to change data cache settings on
1547 a per-section basis.
1549 CONFIG_CONSOLE_SCROLL_LINES
1551 When the console need to be scrolled, this is the number of
1552 lines to scroll by. It defaults to 1. Increasing this makes
1553 the console jump but can help speed up operation when scrolling
1558 Support drawing of RLE8-compressed bitmaps on the LCD.
1562 Enables an 'i2c edid' command which can read EDID
1563 information over I2C from an attached LCD display.
1565 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1567 If this option is set, the environment is checked for
1568 a variable "splashimage". If found, the usual display
1569 of logo, copyright and system information on the LCD
1570 is suppressed and the BMP image at the address
1571 specified in "splashimage" is loaded instead. The
1572 console is redirected to the "nulldev", too. This
1573 allows for a "silent" boot where a splash screen is
1574 loaded very quickly after power-on.
1576 CONFIG_SPLASHIMAGE_GUARD
1578 If this option is set, then U-Boot will prevent the environment
1579 variable "splashimage" from being set to a problematic address
1580 (see README.displaying-bmps and README.arm-unaligned-accesses).
1581 This option is useful for targets where, due to alignment
1582 restrictions, an improperly aligned BMP image will cause a data
1583 abort. If you think you will not have problems with unaligned
1584 accesses (for example because your toolchain prevents them)
1585 there is no need to set this option.
1587 CONFIG_SPLASH_SCREEN_ALIGN
1589 If this option is set the splash image can be freely positioned
1590 on the screen. Environment variable "splashpos" specifies the
1591 position as "x,y". If a positive number is given it is used as
1592 number of pixel from left/top. If a negative number is given it
1593 is used as number of pixel from right/bottom. You can also
1594 specify 'm' for centering the image.
1597 setenv splashpos m,m
1598 => image at center of screen
1600 setenv splashpos 30,20
1601 => image at x = 30 and y = 20
1603 setenv splashpos -10,m
1604 => vertically centered image
1605 at x = dspWidth - bmpWidth - 9
1607 CONFIG_SPLASH_SCREEN_PREPARE
1609 If this option is set then the board_splash_screen_prepare()
1610 function, which must be defined in your code, is called as part
1611 of the splash screen display sequence. It gives the board an
1612 opportunity to prepare the splash image data before it is
1613 processed and sent to the frame buffer by U-Boot.
1615 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1617 If this option is set, additionally to standard BMP
1618 images, gzipped BMP images can be displayed via the
1619 splashscreen support or the bmp command.
1621 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1623 If this option is set, 8-bit RLE compressed BMP images
1624 can be displayed via the splashscreen support or the
1627 - Do compresssing for memory range:
1630 If this option is set, it would use zlib deflate method
1631 to compress the specified memory at its best effort.
1633 - Compression support:
1636 If this option is set, support for bzip2 compressed
1637 images is included. If not, only uncompressed and gzip
1638 compressed images are supported.
1640 NOTE: the bzip2 algorithm requires a lot of RAM, so
1641 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1646 If this option is set, support for lzma compressed
1649 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1650 requires an amount of dynamic memory that is given by the
1653 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1655 Where lc and lp stand for, respectively, Literal context bits
1656 and Literal pos bits.
1658 This value is upper-bounded by 14MB in the worst case. Anyway,
1659 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1660 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1661 a very small buffer.
1663 Use the lzmainfo tool to determinate the lc and lp values and
1664 then calculate the amount of needed dynamic memory (ensuring
1665 the appropriate CONFIG_SYS_MALLOC_LEN value).
1670 The address of PHY on MII bus.
1672 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1674 The clock frequency of the MII bus
1678 If this option is set, support for speed/duplex
1679 detection of gigabit PHY is included.
1681 CONFIG_PHY_RESET_DELAY
1683 Some PHY like Intel LXT971A need extra delay after
1684 reset before any MII register access is possible.
1685 For such PHY, set this option to the usec delay
1686 required. (minimum 300usec for LXT971A)
1688 CONFIG_PHY_CMD_DELAY (ppc4xx)
1690 Some PHY like Intel LXT971A need extra delay after
1691 command issued before MII status register can be read
1701 Define a default value for Ethernet address to use
1702 for the respective Ethernet interface, in case this
1703 is not determined automatically.
1708 Define a default value for the IP address to use for
1709 the default Ethernet interface, in case this is not
1710 determined through e.g. bootp.
1711 (Environment variable "ipaddr")
1713 - Server IP address:
1716 Defines a default value for the IP address of a TFTP
1717 server to contact when using the "tftboot" command.
1718 (Environment variable "serverip")
1720 CONFIG_KEEP_SERVERADDR
1722 Keeps the server's MAC address, in the env 'serveraddr'
1723 for passing to bootargs (like Linux's netconsole option)
1725 - Gateway IP address:
1728 Defines a default value for the IP address of the
1729 default router where packets to other networks are
1731 (Environment variable "gatewayip")
1736 Defines a default value for the subnet mask (or
1737 routing prefix) which is used to determine if an IP
1738 address belongs to the local subnet or needs to be
1739 forwarded through a router.
1740 (Environment variable "netmask")
1742 - Multicast TFTP Mode:
1745 Defines whether you want to support multicast TFTP as per
1746 rfc-2090; for example to work with atftp. Lets lots of targets
1747 tftp down the same boot image concurrently. Note: the Ethernet
1748 driver in use must provide a function: mcast() to join/leave a
1751 - BOOTP Recovery Mode:
1752 CONFIG_BOOTP_RANDOM_DELAY
1754 If you have many targets in a network that try to
1755 boot using BOOTP, you may want to avoid that all
1756 systems send out BOOTP requests at precisely the same
1757 moment (which would happen for instance at recovery
1758 from a power failure, when all systems will try to
1759 boot, thus flooding the BOOTP server. Defining
1760 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1761 inserted before sending out BOOTP requests. The
1762 following delays are inserted then:
1764 1st BOOTP request: delay 0 ... 1 sec
1765 2nd BOOTP request: delay 0 ... 2 sec
1766 3rd BOOTP request: delay 0 ... 4 sec
1768 BOOTP requests: delay 0 ... 8 sec
1770 - DHCP Advanced Options:
1771 You can fine tune the DHCP functionality by defining
1772 CONFIG_BOOTP_* symbols:
1774 CONFIG_BOOTP_SUBNETMASK
1775 CONFIG_BOOTP_GATEWAY
1776 CONFIG_BOOTP_HOSTNAME
1777 CONFIG_BOOTP_NISDOMAIN
1778 CONFIG_BOOTP_BOOTPATH
1779 CONFIG_BOOTP_BOOTFILESIZE
1782 CONFIG_BOOTP_SEND_HOSTNAME
1783 CONFIG_BOOTP_NTPSERVER
1784 CONFIG_BOOTP_TIMEOFFSET
1785 CONFIG_BOOTP_VENDOREX
1786 CONFIG_BOOTP_MAY_FAIL
1788 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1789 environment variable, not the BOOTP server.
1791 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1792 after the configured retry count, the call will fail
1793 instead of starting over. This can be used to fail over
1794 to Link-local IP address configuration if the DHCP server
1797 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1798 serverip from a DHCP server, it is possible that more
1799 than one DNS serverip is offered to the client.
1800 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1801 serverip will be stored in the additional environment
1802 variable "dnsip2". The first DNS serverip is always
1803 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1806 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1807 to do a dynamic update of a DNS server. To do this, they
1808 need the hostname of the DHCP requester.
1809 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1810 of the "hostname" environment variable is passed as
1811 option 12 to the DHCP server.
1813 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1815 A 32bit value in microseconds for a delay between
1816 receiving a "DHCP Offer" and sending the "DHCP Request".
1817 This fixes a problem with certain DHCP servers that don't
1818 respond 100% of the time to a "DHCP request". E.g. On an
1819 AT91RM9200 processor running at 180MHz, this delay needed
1820 to be *at least* 15,000 usec before a Windows Server 2003
1821 DHCP server would reply 100% of the time. I recommend at
1822 least 50,000 usec to be safe. The alternative is to hope
1823 that one of the retries will be successful but note that
1824 the DHCP timeout and retry process takes a longer than
1827 - Link-local IP address negotiation:
1828 Negotiate with other link-local clients on the local network
1829 for an address that doesn't require explicit configuration.
1830 This is especially useful if a DHCP server cannot be guaranteed
1831 to exist in all environments that the device must operate.
1833 See doc/README.link-local for more information.
1836 CONFIG_CDP_DEVICE_ID
1838 The device id used in CDP trigger frames.
1840 CONFIG_CDP_DEVICE_ID_PREFIX
1842 A two character string which is prefixed to the MAC address
1847 A printf format string which contains the ascii name of
1848 the port. Normally is set to "eth%d" which sets
1849 eth0 for the first Ethernet, eth1 for the second etc.
1851 CONFIG_CDP_CAPABILITIES
1853 A 32bit integer which indicates the device capabilities;
1854 0x00000010 for a normal host which does not forwards.
1858 An ascii string containing the version of the software.
1862 An ascii string containing the name of the platform.
1866 A 32bit integer sent on the trigger.
1868 CONFIG_CDP_POWER_CONSUMPTION
1870 A 16bit integer containing the power consumption of the
1871 device in .1 of milliwatts.
1873 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1875 A byte containing the id of the VLAN.
1877 - Status LED: CONFIG_STATUS_LED
1879 Several configurations allow to display the current
1880 status using a LED. For instance, the LED will blink
1881 fast while running U-Boot code, stop blinking as
1882 soon as a reply to a BOOTP request was received, and
1883 start blinking slow once the Linux kernel is running
1884 (supported by a status LED driver in the Linux
1885 kernel). Defining CONFIG_STATUS_LED enables this
1888 - CAN Support: CONFIG_CAN_DRIVER
1890 Defining CONFIG_CAN_DRIVER enables CAN driver support
1891 on those systems that support this (optional)
1892 feature, like the TQM8xxL modules.
1894 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1896 These enable I2C serial bus commands. Defining either of
1897 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1898 include the appropriate I2C driver for the selected CPU.
1900 This will allow you to use i2c commands at the u-boot
1901 command line (as long as you set CONFIG_CMD_I2C in
1902 CONFIG_COMMANDS) and communicate with i2c based realtime
1903 clock chips. See common/cmd_i2c.c for a description of the
1904 command line interface.
1906 CONFIG_HARD_I2C selects a hardware I2C controller.
1908 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1909 bit-banging) driver instead of CPM or similar hardware
1912 There are several other quantities that must also be
1913 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1915 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1916 to be the frequency (in Hz) at which you wish your i2c bus
1917 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1918 the CPU's i2c node address).
1920 Now, the u-boot i2c code for the mpc8xx
1921 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1922 and so its address should therefore be cleared to 0 (See,
1923 eg, MPC823e User's Manual p.16-473). So, set
1924 CONFIG_SYS_I2C_SLAVE to 0.
1926 CONFIG_SYS_I2C_INIT_MPC5XXX
1928 When a board is reset during an i2c bus transfer
1929 chips might think that the current transfer is still
1930 in progress. Reset the slave devices by sending start
1931 commands until the slave device responds.
1933 That's all that's required for CONFIG_HARD_I2C.
1935 If you use the software i2c interface (CONFIG_SOFT_I2C)
1936 then the following macros need to be defined (examples are
1937 from include/configs/lwmon.h):
1941 (Optional). Any commands necessary to enable the I2C
1942 controller or configure ports.
1944 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1948 (Only for MPC8260 CPU). The I/O port to use (the code
1949 assumes both bits are on the same port). Valid values
1950 are 0..3 for ports A..D.
1954 The code necessary to make the I2C data line active
1955 (driven). If the data line is open collector, this
1958 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1962 The code necessary to make the I2C data line tri-stated
1963 (inactive). If the data line is open collector, this
1966 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1970 Code that returns true if the I2C data line is high,
1973 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1977 If <bit> is true, sets the I2C data line high. If it
1978 is false, it clears it (low).
1980 eg: #define I2C_SDA(bit) \
1981 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1982 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1986 If <bit> is true, sets the I2C clock line high. If it
1987 is false, it clears it (low).
1989 eg: #define I2C_SCL(bit) \
1990 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1991 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1995 This delay is invoked four times per clock cycle so this
1996 controls the rate of data transfer. The data rate thus
1997 is 1 / (I2C_DELAY * 4). Often defined to be something
2000 #define I2C_DELAY udelay(2)
2002 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2004 If your arch supports the generic GPIO framework (asm/gpio.h),
2005 then you may alternatively define the two GPIOs that are to be
2006 used as SCL / SDA. Any of the previous I2C_xxx macros will
2007 have GPIO-based defaults assigned to them as appropriate.
2009 You should define these to the GPIO value as given directly to
2010 the generic GPIO functions.
2012 CONFIG_SYS_I2C_INIT_BOARD
2014 When a board is reset during an i2c bus transfer
2015 chips might think that the current transfer is still
2016 in progress. On some boards it is possible to access
2017 the i2c SCLK line directly, either by using the
2018 processor pin as a GPIO or by having a second pin
2019 connected to the bus. If this option is defined a
2020 custom i2c_init_board() routine in boards/xxx/board.c
2021 is run early in the boot sequence.
2023 CONFIG_SYS_I2C_BOARD_LATE_INIT
2025 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2026 defined a custom i2c_board_late_init() routine in
2027 boards/xxx/board.c is run AFTER the operations in i2c_init()
2028 is completed. This callpoint can be used to unreset i2c bus
2029 using CPU i2c controller register accesses for CPUs whose i2c
2030 controller provide such a method. It is called at the end of
2031 i2c_init() to allow i2c_init operations to setup the i2c bus
2032 controller on the CPU (e.g. setting bus speed & slave address).
2034 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2036 This option enables configuration of bi_iic_fast[] flags
2037 in u-boot bd_info structure based on u-boot environment
2038 variable "i2cfast". (see also i2cfast)
2040 CONFIG_I2C_MULTI_BUS
2042 This option allows the use of multiple I2C buses, each of which
2043 must have a controller. At any point in time, only one bus is
2044 active. To switch to a different bus, use the 'i2c dev' command.
2045 Note that bus numbering is zero-based.
2047 CONFIG_SYS_I2C_NOPROBES
2049 This option specifies a list of I2C devices that will be skipped
2050 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2051 is set, specify a list of bus-device pairs. Otherwise, specify
2052 a 1D array of device addresses
2055 #undef CONFIG_I2C_MULTI_BUS
2056 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2058 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2060 #define CONFIG_I2C_MULTI_BUS
2061 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2063 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2065 CONFIG_SYS_SPD_BUS_NUM
2067 If defined, then this indicates the I2C bus number for DDR SPD.
2068 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2070 CONFIG_SYS_RTC_BUS_NUM
2072 If defined, then this indicates the I2C bus number for the RTC.
2073 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2075 CONFIG_SYS_DTT_BUS_NUM
2077 If defined, then this indicates the I2C bus number for the DTT.
2078 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2080 CONFIG_SYS_I2C_DTT_ADDR:
2082 If defined, specifies the I2C address of the DTT device.
2083 If not defined, then U-Boot uses predefined value for
2084 specified DTT device.
2088 Define this option if you want to use Freescale's I2C driver in
2089 drivers/i2c/fsl_i2c.c.
2093 Define this option if you have I2C devices reached over 1 .. n
2094 I2C Muxes like the pca9544a. This option addes a new I2C
2095 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
2096 new I2C Bus to the existing I2C Busses. If you select the
2097 new Bus with "i2c dev", u-bbot sends first the commandos for
2098 the muxes to activate this new "bus".
2100 CONFIG_I2C_MULTI_BUS must be also defined, to use this
2104 Adding a new I2C Bus reached over 2 pca9544a muxes
2105 The First mux with address 70 and channel 6
2106 The Second mux with address 71 and channel 4
2108 => i2c bus pca9544a:70:6:pca9544a:71:4
2110 Use the "i2c bus" command without parameter, to get a list
2111 of I2C Busses with muxes:
2114 Busses reached over muxes:
2116 reached over Mux(es):
2119 reached over Mux(es):
2124 If you now switch to the new I2C Bus 3 with "i2c dev 3"
2125 u-boot first sends the command to the mux@70 to enable
2126 channel 6, and then the command to the mux@71 to enable
2129 After that, you can use the "normal" i2c commands as
2130 usual to communicate with your I2C devices behind
2133 This option is actually implemented for the bitbanging
2134 algorithm in common/soft_i2c.c and for the Hardware I2C
2135 Bus on the MPC8260. But it should be not so difficult
2136 to add this option to other architectures.
2138 CONFIG_SOFT_I2C_READ_REPEATED_START
2140 defining this will force the i2c_read() function in
2141 the soft_i2c driver to perform an I2C repeated start
2142 between writing the address pointer and reading the
2143 data. If this define is omitted the default behaviour
2144 of doing a stop-start sequence will be used. Most I2C
2145 devices can use either method, but some require one or
2148 - SPI Support: CONFIG_SPI
2150 Enables SPI driver (so far only tested with
2151 SPI EEPROM, also an instance works with Crystal A/D and
2152 D/As on the SACSng board)
2156 Enables the driver for SPI controller on SuperH. Currently
2157 only SH7757 is supported.
2161 Enables extended (16-bit) SPI EEPROM addressing.
2162 (symmetrical to CONFIG_I2C_X)
2166 Enables a software (bit-bang) SPI driver rather than
2167 using hardware support. This is a general purpose
2168 driver that only requires three general I/O port pins
2169 (two outputs, one input) to function. If this is
2170 defined, the board configuration must define several
2171 SPI configuration items (port pins to use, etc). For
2172 an example, see include/configs/sacsng.h.
2176 Enables a hardware SPI driver for general-purpose reads
2177 and writes. As with CONFIG_SOFT_SPI, the board configuration
2178 must define a list of chip-select function pointers.
2179 Currently supported on some MPC8xxx processors. For an
2180 example, see include/configs/mpc8349emds.h.
2184 Enables the driver for the SPI controllers on i.MX and MXC
2185 SoCs. Currently i.MX31/35/51 are supported.
2187 - FPGA Support: CONFIG_FPGA
2189 Enables FPGA subsystem.
2191 CONFIG_FPGA_<vendor>
2193 Enables support for specific chip vendors.
2196 CONFIG_FPGA_<family>
2198 Enables support for FPGA family.
2199 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2203 Specify the number of FPGA devices to support.
2205 CONFIG_SYS_FPGA_PROG_FEEDBACK
2207 Enable printing of hash marks during FPGA configuration.
2209 CONFIG_SYS_FPGA_CHECK_BUSY
2211 Enable checks on FPGA configuration interface busy
2212 status by the configuration function. This option
2213 will require a board or device specific function to
2218 If defined, a function that provides delays in the FPGA
2219 configuration driver.
2221 CONFIG_SYS_FPGA_CHECK_CTRLC
2222 Allow Control-C to interrupt FPGA configuration
2224 CONFIG_SYS_FPGA_CHECK_ERROR
2226 Check for configuration errors during FPGA bitfile
2227 loading. For example, abort during Virtex II
2228 configuration if the INIT_B line goes low (which
2229 indicated a CRC error).
2231 CONFIG_SYS_FPGA_WAIT_INIT
2233 Maximum time to wait for the INIT_B line to deassert
2234 after PROB_B has been deasserted during a Virtex II
2235 FPGA configuration sequence. The default time is 500
2238 CONFIG_SYS_FPGA_WAIT_BUSY
2240 Maximum time to wait for BUSY to deassert during
2241 Virtex II FPGA configuration. The default is 5 ms.
2243 CONFIG_SYS_FPGA_WAIT_CONFIG
2245 Time to wait after FPGA configuration. The default is
2248 - Configuration Management:
2251 If defined, this string will be added to the U-Boot
2252 version information (U_BOOT_VERSION)
2254 - Vendor Parameter Protection:
2256 U-Boot considers the values of the environment
2257 variables "serial#" (Board Serial Number) and
2258 "ethaddr" (Ethernet Address) to be parameters that
2259 are set once by the board vendor / manufacturer, and
2260 protects these variables from casual modification by
2261 the user. Once set, these variables are read-only,
2262 and write or delete attempts are rejected. You can
2263 change this behaviour:
2265 If CONFIG_ENV_OVERWRITE is #defined in your config
2266 file, the write protection for vendor parameters is
2267 completely disabled. Anybody can change or delete
2270 Alternatively, if you #define _both_ CONFIG_ETHADDR
2271 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2272 Ethernet address is installed in the environment,
2273 which can be changed exactly ONCE by the user. [The
2274 serial# is unaffected by this, i. e. it remains
2277 The same can be accomplished in a more flexible way
2278 for any variable by configuring the type of access
2279 to allow for those variables in the ".flags" variable
2280 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2285 Define this variable to enable the reservation of
2286 "protected RAM", i. e. RAM which is not overwritten
2287 by U-Boot. Define CONFIG_PRAM to hold the number of
2288 kB you want to reserve for pRAM. You can overwrite
2289 this default value by defining an environment
2290 variable "pram" to the number of kB you want to
2291 reserve. Note that the board info structure will
2292 still show the full amount of RAM. If pRAM is
2293 reserved, a new environment variable "mem" will
2294 automatically be defined to hold the amount of
2295 remaining RAM in a form that can be passed as boot
2296 argument to Linux, for instance like that:
2298 setenv bootargs ... mem=\${mem}
2301 This way you can tell Linux not to use this memory,
2302 either, which results in a memory region that will
2303 not be affected by reboots.
2305 *WARNING* If your board configuration uses automatic
2306 detection of the RAM size, you must make sure that
2307 this memory test is non-destructive. So far, the
2308 following board configurations are known to be
2311 IVMS8, IVML24, SPD8xx, TQM8xxL,
2312 HERMES, IP860, RPXlite, LWMON,
2315 - Access to physical memory region (> 4GB)
2316 Some basic support is provided for operations on memory not
2317 normally accessible to U-Boot - e.g. some architectures
2318 support access to more than 4GB of memory on 32-bit
2319 machines using physical address extension or similar.
2320 Define CONFIG_PHYSMEM to access this basic support, which
2321 currently only supports clearing the memory.
2326 Define this variable to stop the system in case of a
2327 fatal error, so that you have to reset it manually.
2328 This is probably NOT a good idea for an embedded
2329 system where you want the system to reboot
2330 automatically as fast as possible, but it may be
2331 useful during development since you can try to debug
2332 the conditions that lead to the situation.
2334 CONFIG_NET_RETRY_COUNT
2336 This variable defines the number of retries for
2337 network operations like ARP, RARP, TFTP, or BOOTP
2338 before giving up the operation. If not defined, a
2339 default value of 5 is used.
2343 Timeout waiting for an ARP reply in milliseconds.
2347 Timeout in milliseconds used in NFS protocol.
2348 If you encounter "ERROR: Cannot umount" in nfs command,
2349 try longer timeout such as
2350 #define CONFIG_NFS_TIMEOUT 10000UL
2352 - Command Interpreter:
2353 CONFIG_AUTO_COMPLETE
2355 Enable auto completion of commands using TAB.
2357 Note that this feature has NOT been implemented yet
2358 for the "hush" shell.
2361 CONFIG_SYS_HUSH_PARSER
2363 Define this variable to enable the "hush" shell (from
2364 Busybox) as command line interpreter, thus enabling
2365 powerful command line syntax like
2366 if...then...else...fi conditionals or `&&' and '||'
2367 constructs ("shell scripts").
2369 If undefined, you get the old, much simpler behaviour
2370 with a somewhat smaller memory footprint.
2373 CONFIG_SYS_PROMPT_HUSH_PS2
2375 This defines the secondary prompt string, which is
2376 printed when the command interpreter needs more input
2377 to complete a command. Usually "> ".
2381 In the current implementation, the local variables
2382 space and global environment variables space are
2383 separated. Local variables are those you define by
2384 simply typing `name=value'. To access a local
2385 variable later on, you have write `$name' or
2386 `${name}'; to execute the contents of a variable
2387 directly type `$name' at the command prompt.
2389 Global environment variables are those you use
2390 setenv/printenv to work with. To run a command stored
2391 in such a variable, you need to use the run command,
2392 and you must not use the '$' sign to access them.
2394 To store commands and special characters in a
2395 variable, please use double quotation marks
2396 surrounding the whole text of the variable, instead
2397 of the backslashes before semicolons and special
2400 - Commandline Editing and History:
2401 CONFIG_CMDLINE_EDITING
2403 Enable editing and History functions for interactive
2404 commandline input operations
2406 - Default Environment:
2407 CONFIG_EXTRA_ENV_SETTINGS
2409 Define this to contain any number of null terminated
2410 strings (variable = value pairs) that will be part of
2411 the default environment compiled into the boot image.
2413 For example, place something like this in your
2414 board's config file:
2416 #define CONFIG_EXTRA_ENV_SETTINGS \
2420 Warning: This method is based on knowledge about the
2421 internal format how the environment is stored by the
2422 U-Boot code. This is NOT an official, exported
2423 interface! Although it is unlikely that this format
2424 will change soon, there is no guarantee either.
2425 You better know what you are doing here.
2427 Note: overly (ab)use of the default environment is
2428 discouraged. Make sure to check other ways to preset
2429 the environment like the "source" command or the
2432 CONFIG_ENV_VARS_UBOOT_CONFIG
2434 Define this in order to add variables describing the
2435 U-Boot build configuration to the default environment.
2436 These will be named arch, cpu, board, vendor, and soc.
2438 Enabling this option will cause the following to be defined:
2446 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2448 Define this in order to add variables describing certain
2449 run-time determined information about the hardware to the
2450 environment. These will be named board_name, board_rev.
2452 CONFIG_DELAY_ENVIRONMENT
2454 Normally the environment is loaded when the board is
2455 intialised so that it is available to U-Boot. This inhibits
2456 that so that the environment is not available until
2457 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2458 this is instead controlled by the value of
2459 /config/load-environment.
2461 - DataFlash Support:
2462 CONFIG_HAS_DATAFLASH
2464 Defining this option enables DataFlash features and
2465 allows to read/write in Dataflash via the standard
2468 - Serial Flash support
2471 Defining this option enables SPI flash commands
2472 'sf probe/read/write/erase/update'.
2474 Usage requires an initial 'probe' to define the serial
2475 flash parameters, followed by read/write/erase/update
2478 The following defaults may be provided by the platform
2479 to handle the common case when only a single serial
2480 flash is present on the system.
2482 CONFIG_SF_DEFAULT_BUS Bus identifier
2483 CONFIG_SF_DEFAULT_CS Chip-select
2484 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2485 CONFIG_SF_DEFAULT_SPEED in Hz
2489 Define this option to include a destructive SPI flash
2492 - SystemACE Support:
2495 Adding this option adds support for Xilinx SystemACE
2496 chips attached via some sort of local bus. The address
2497 of the chip must also be defined in the
2498 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2500 #define CONFIG_SYSTEMACE
2501 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2503 When SystemACE support is added, the "ace" device type
2504 becomes available to the fat commands, i.e. fatls.
2506 - TFTP Fixed UDP Port:
2509 If this is defined, the environment variable tftpsrcp
2510 is used to supply the TFTP UDP source port value.
2511 If tftpsrcp isn't defined, the normal pseudo-random port
2512 number generator is used.
2514 Also, the environment variable tftpdstp is used to supply
2515 the TFTP UDP destination port value. If tftpdstp isn't
2516 defined, the normal port 69 is used.
2518 The purpose for tftpsrcp is to allow a TFTP server to
2519 blindly start the TFTP transfer using the pre-configured
2520 target IP address and UDP port. This has the effect of
2521 "punching through" the (Windows XP) firewall, allowing
2522 the remainder of the TFTP transfer to proceed normally.
2523 A better solution is to properly configure the firewall,
2524 but sometimes that is not allowed.
2529 This enables a generic 'hash' command which can produce
2530 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2534 Enable the hash verify command (hash -v). This adds to code
2537 CONFIG_SHA1 - support SHA1 hashing
2538 CONFIG_SHA256 - support SHA256 hashing
2540 Note: There is also a sha1sum command, which should perhaps
2541 be deprecated in favour of 'hash sha1'.
2543 - Show boot progress:
2544 CONFIG_SHOW_BOOT_PROGRESS
2546 Defining this option allows to add some board-
2547 specific code (calling a user-provided function
2548 "show_boot_progress(int)") that enables you to show
2549 the system's boot progress on some display (for
2550 example, some LED's) on your board. At the moment,
2551 the following checkpoints are implemented:
2553 - Detailed boot stage timing
2555 Define this option to get detailed timing of each stage
2556 of the boot process.
2558 CONFIG_BOOTSTAGE_USER_COUNT
2559 This is the number of available user bootstage records.
2560 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2561 a new ID will be allocated from this stash. If you exceed
2562 the limit, recording will stop.
2564 CONFIG_BOOTSTAGE_REPORT
2565 Define this to print a report before boot, similar to this:
2567 Timer summary in microseconds:
2570 3,575,678 3,575,678 board_init_f start
2571 3,575,695 17 arch_cpu_init A9
2572 3,575,777 82 arch_cpu_init done
2573 3,659,598 83,821 board_init_r start
2574 3,910,375 250,777 main_loop
2575 29,916,167 26,005,792 bootm_start
2576 30,361,327 445,160 start_kernel
2578 CONFIG_CMD_BOOTSTAGE
2579 Add a 'bootstage' command which supports printing a report
2580 and un/stashing of bootstage data.
2582 CONFIG_BOOTSTAGE_FDT
2583 Stash the bootstage information in the FDT. A root 'bootstage'
2584 node is created with each bootstage id as a child. Each child
2585 has a 'name' property and either 'mark' containing the
2586 mark time in microsecond, or 'accum' containing the
2587 accumulated time for that bootstage id in microseconds.
2592 name = "board_init_f";
2601 Code in the Linux kernel can find this in /proc/devicetree.
2603 Legacy uImage format:
2606 1 common/cmd_bootm.c before attempting to boot an image
2607 -1 common/cmd_bootm.c Image header has bad magic number
2608 2 common/cmd_bootm.c Image header has correct magic number
2609 -2 common/cmd_bootm.c Image header has bad checksum
2610 3 common/cmd_bootm.c Image header has correct checksum
2611 -3 common/cmd_bootm.c Image data has bad checksum
2612 4 common/cmd_bootm.c Image data has correct checksum
2613 -4 common/cmd_bootm.c Image is for unsupported architecture
2614 5 common/cmd_bootm.c Architecture check OK
2615 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2616 6 common/cmd_bootm.c Image Type check OK
2617 -6 common/cmd_bootm.c gunzip uncompression error
2618 -7 common/cmd_bootm.c Unimplemented compression type
2619 7 common/cmd_bootm.c Uncompression OK
2620 8 common/cmd_bootm.c No uncompress/copy overwrite error
2621 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2623 9 common/image.c Start initial ramdisk verification
2624 -10 common/image.c Ramdisk header has bad magic number
2625 -11 common/image.c Ramdisk header has bad checksum
2626 10 common/image.c Ramdisk header is OK
2627 -12 common/image.c Ramdisk data has bad checksum
2628 11 common/image.c Ramdisk data has correct checksum
2629 12 common/image.c Ramdisk verification complete, start loading
2630 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2631 13 common/image.c Start multifile image verification
2632 14 common/image.c No initial ramdisk, no multifile, continue.
2634 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2636 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2637 -31 post/post.c POST test failed, detected by post_output_backlog()
2638 -32 post/post.c POST test failed, detected by post_run_single()
2640 34 common/cmd_doc.c before loading a Image from a DOC device
2641 -35 common/cmd_doc.c Bad usage of "doc" command
2642 35 common/cmd_doc.c correct usage of "doc" command
2643 -36 common/cmd_doc.c No boot device
2644 36 common/cmd_doc.c correct boot device
2645 -37 common/cmd_doc.c Unknown Chip ID on boot device
2646 37 common/cmd_doc.c correct chip ID found, device available
2647 -38 common/cmd_doc.c Read Error on boot device
2648 38 common/cmd_doc.c reading Image header from DOC device OK
2649 -39 common/cmd_doc.c Image header has bad magic number
2650 39 common/cmd_doc.c Image header has correct magic number
2651 -40 common/cmd_doc.c Error reading Image from DOC device
2652 40 common/cmd_doc.c Image header has correct magic number
2653 41 common/cmd_ide.c before loading a Image from a IDE device
2654 -42 common/cmd_ide.c Bad usage of "ide" command
2655 42 common/cmd_ide.c correct usage of "ide" command
2656 -43 common/cmd_ide.c No boot device
2657 43 common/cmd_ide.c boot device found
2658 -44 common/cmd_ide.c Device not available
2659 44 common/cmd_ide.c Device available
2660 -45 common/cmd_ide.c wrong partition selected
2661 45 common/cmd_ide.c partition selected
2662 -46 common/cmd_ide.c Unknown partition table
2663 46 common/cmd_ide.c valid partition table found
2664 -47 common/cmd_ide.c Invalid partition type
2665 47 common/cmd_ide.c correct partition type
2666 -48 common/cmd_ide.c Error reading Image Header on boot device
2667 48 common/cmd_ide.c reading Image Header from IDE device OK
2668 -49 common/cmd_ide.c Image header has bad magic number
2669 49 common/cmd_ide.c Image header has correct magic number
2670 -50 common/cmd_ide.c Image header has bad checksum
2671 50 common/cmd_ide.c Image header has correct checksum
2672 -51 common/cmd_ide.c Error reading Image from IDE device
2673 51 common/cmd_ide.c reading Image from IDE device OK
2674 52 common/cmd_nand.c before loading a Image from a NAND device
2675 -53 common/cmd_nand.c Bad usage of "nand" command
2676 53 common/cmd_nand.c correct usage of "nand" command
2677 -54 common/cmd_nand.c No boot device
2678 54 common/cmd_nand.c boot device found
2679 -55 common/cmd_nand.c Unknown Chip ID on boot device
2680 55 common/cmd_nand.c correct chip ID found, device available
2681 -56 common/cmd_nand.c Error reading Image Header on boot device
2682 56 common/cmd_nand.c reading Image Header from NAND device OK
2683 -57 common/cmd_nand.c Image header has bad magic number
2684 57 common/cmd_nand.c Image header has correct magic number
2685 -58 common/cmd_nand.c Error reading Image from NAND device
2686 58 common/cmd_nand.c reading Image from NAND device OK
2688 -60 common/env_common.c Environment has a bad CRC, using default
2690 64 net/eth.c starting with Ethernet configuration.
2691 -64 net/eth.c no Ethernet found.
2692 65 net/eth.c Ethernet found.
2694 -80 common/cmd_net.c usage wrong
2695 80 common/cmd_net.c before calling NetLoop()
2696 -81 common/cmd_net.c some error in NetLoop() occurred
2697 81 common/cmd_net.c NetLoop() back without error
2698 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2699 82 common/cmd_net.c trying automatic boot
2700 83 common/cmd_net.c running "source" command
2701 -83 common/cmd_net.c some error in automatic boot or "source" command
2702 84 common/cmd_net.c end without errors
2707 100 common/cmd_bootm.c Kernel FIT Image has correct format
2708 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2709 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2710 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2711 102 common/cmd_bootm.c Kernel unit name specified
2712 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2713 103 common/cmd_bootm.c Found configuration node
2714 104 common/cmd_bootm.c Got kernel subimage node offset
2715 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2716 105 common/cmd_bootm.c Kernel subimage hash verification OK
2717 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2718 106 common/cmd_bootm.c Architecture check OK
2719 -106 common/cmd_bootm.c Kernel subimage has wrong type
2720 107 common/cmd_bootm.c Kernel subimage type OK
2721 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2722 108 common/cmd_bootm.c Got kernel subimage data/size
2723 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2724 -109 common/cmd_bootm.c Can't get kernel subimage type
2725 -110 common/cmd_bootm.c Can't get kernel subimage comp
2726 -111 common/cmd_bootm.c Can't get kernel subimage os
2727 -112 common/cmd_bootm.c Can't get kernel subimage load address
2728 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2730 120 common/image.c Start initial ramdisk verification
2731 -120 common/image.c Ramdisk FIT image has incorrect format
2732 121 common/image.c Ramdisk FIT image has correct format
2733 122 common/image.c No ramdisk subimage unit name, using configuration
2734 -122 common/image.c Can't get configuration for ramdisk subimage
2735 123 common/image.c Ramdisk unit name specified
2736 -124 common/image.c Can't get ramdisk subimage node offset
2737 125 common/image.c Got ramdisk subimage node offset
2738 -125 common/image.c Ramdisk subimage hash verification failed
2739 126 common/image.c Ramdisk subimage hash verification OK
2740 -126 common/image.c Ramdisk subimage for unsupported architecture
2741 127 common/image.c Architecture check OK
2742 -127 common/image.c Can't get ramdisk subimage data/size
2743 128 common/image.c Got ramdisk subimage data/size
2744 129 common/image.c Can't get ramdisk load address
2745 -129 common/image.c Got ramdisk load address
2747 -130 common/cmd_doc.c Incorrect FIT image format
2748 131 common/cmd_doc.c FIT image format OK
2750 -140 common/cmd_ide.c Incorrect FIT image format
2751 141 common/cmd_ide.c FIT image format OK
2753 -150 common/cmd_nand.c Incorrect FIT image format
2754 151 common/cmd_nand.c FIT image format OK
2756 - FIT image support:
2758 Enable support for the FIT uImage format.
2760 CONFIG_FIT_BEST_MATCH
2761 When no configuration is explicitly selected, default to the
2762 one whose fdt's compatibility field best matches that of
2763 U-Boot itself. A match is considered "best" if it matches the
2764 most specific compatibility entry of U-Boot's fdt's root node.
2765 The order of entries in the configuration's fdt is ignored.
2767 - Standalone program support:
2768 CONFIG_STANDALONE_LOAD_ADDR
2770 This option defines a board specific value for the
2771 address where standalone program gets loaded, thus
2772 overwriting the architecture dependent default
2775 - Frame Buffer Address:
2778 Define CONFIG_FB_ADDR if you want to use specific
2779 address for frame buffer. This is typically the case
2780 when using a graphics controller has separate video
2781 memory. U-Boot will then place the frame buffer at
2782 the given address instead of dynamically reserving it
2783 in system RAM by calling lcd_setmem(), which grabs
2784 the memory for the frame buffer depending on the
2785 configured panel size.
2787 Please see board_init_f function.
2789 - Automatic software updates via TFTP server
2791 CONFIG_UPDATE_TFTP_CNT_MAX
2792 CONFIG_UPDATE_TFTP_MSEC_MAX
2794 These options enable and control the auto-update feature;
2795 for a more detailed description refer to doc/README.update.
2797 - MTD Support (mtdparts command, UBI support)
2800 Adds the MTD device infrastructure from the Linux kernel.
2801 Needed for mtdparts command support.
2803 CONFIG_MTD_PARTITIONS
2805 Adds the MTD partitioning infrastructure from the Linux
2806 kernel. Needed for UBI support.
2811 Adds commands for interacting with MTD partitions formatted
2812 with the UBI flash translation layer
2814 Requires also defining CONFIG_RBTREE
2816 CONFIG_UBI_SILENCE_MSG
2818 Make the verbose messages from UBI stop printing. This leaves
2819 warnings and errors enabled.
2824 Adds commands for interacting with UBI volumes formatted as
2825 UBIFS. UBIFS is read-only in u-boot.
2827 Requires UBI support as well as CONFIG_LZO
2829 CONFIG_UBIFS_SILENCE_MSG
2831 Make the verbose messages from UBIFS stop printing. This leaves
2832 warnings and errors enabled.
2836 Enable building of SPL globally.
2839 LDSCRIPT for linking the SPL binary.
2841 CONFIG_SPL_MAX_FOOTPRINT
2842 Maximum size in memory allocated to the SPL, BSS included.
2843 When defined, the linker checks that the actual memory
2844 used by SPL from _start to __bss_end does not exceed it.
2845 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2846 must not be both defined at the same time.
2849 Maximum size of the SPL image (text, data, rodata, and
2850 linker lists sections), BSS excluded.
2851 When defined, the linker checks that the actual size does
2854 CONFIG_SPL_TEXT_BASE
2855 TEXT_BASE for linking the SPL binary.
2857 CONFIG_SPL_RELOC_TEXT_BASE
2858 Address to relocate to. If unspecified, this is equal to
2859 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2861 CONFIG_SPL_BSS_START_ADDR
2862 Link address for the BSS within the SPL binary.
2864 CONFIG_SPL_BSS_MAX_SIZE
2865 Maximum size in memory allocated to the SPL BSS.
2866 When defined, the linker checks that the actual memory used
2867 by SPL from __bss_start to __bss_end does not exceed it.
2868 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2869 must not be both defined at the same time.
2872 Adress of the start of the stack SPL will use
2874 CONFIG_SPL_RELOC_STACK
2875 Adress of the start of the stack SPL will use after
2876 relocation. If unspecified, this is equal to
2879 CONFIG_SYS_SPL_MALLOC_START
2880 Starting address of the malloc pool used in SPL.
2882 CONFIG_SYS_SPL_MALLOC_SIZE
2883 The size of the malloc pool used in SPL.
2885 CONFIG_SPL_FRAMEWORK
2886 Enable the SPL framework under common/. This framework
2887 supports MMC, NAND and YMODEM loading of U-Boot and NAND
2888 NAND loading of the Linux Kernel.
2890 CONFIG_SPL_DISPLAY_PRINT
2891 For ARM, enable an optional function to print more information
2892 about the running system.
2894 CONFIG_SPL_INIT_MINIMAL
2895 Arch init code should be built for a very small image
2897 CONFIG_SPL_LIBCOMMON_SUPPORT
2898 Support for common/libcommon.o in SPL binary
2900 CONFIG_SPL_LIBDISK_SUPPORT
2901 Support for disk/libdisk.o in SPL binary
2903 CONFIG_SPL_I2C_SUPPORT
2904 Support for drivers/i2c/libi2c.o in SPL binary
2906 CONFIG_SPL_GPIO_SUPPORT
2907 Support for drivers/gpio/libgpio.o in SPL binary
2909 CONFIG_SPL_MMC_SUPPORT
2910 Support for drivers/mmc/libmmc.o in SPL binary
2912 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2913 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2914 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2915 Address, size and partition on the MMC to load U-Boot from
2916 when the MMC is being used in raw mode.
2918 CONFIG_SPL_FAT_SUPPORT
2919 Support for fs/fat/libfat.o in SPL binary
2921 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2922 Filename to read to load U-Boot when reading from FAT
2924 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2925 Set this for NAND SPL on PPC mpc83xx targets, so that
2926 start.S waits for the rest of the SPL to load before
2927 continuing (the hardware starts execution after just
2928 loading the first page rather than the full 4K).
2930 CONFIG_SPL_NAND_BASE
2931 Include nand_base.c in the SPL. Requires
2932 CONFIG_SPL_NAND_DRIVERS.
2934 CONFIG_SPL_NAND_DRIVERS
2935 SPL uses normal NAND drivers, not minimal drivers.
2938 Include standard software ECC in the SPL
2940 CONFIG_SPL_NAND_SIMPLE
2941 Support for NAND boot using simple NAND drivers that
2942 expose the cmd_ctrl() interface.
2944 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2945 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2946 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2947 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2948 CONFIG_SYS_NAND_ECCBYTES
2949 Defines the size and behavior of the NAND that SPL uses
2952 CONFIG_SYS_NAND_U_BOOT_OFFS
2953 Location in NAND to read U-Boot from
2955 CONFIG_SYS_NAND_U_BOOT_DST
2956 Location in memory to load U-Boot to
2958 CONFIG_SYS_NAND_U_BOOT_SIZE
2959 Size of image to load
2961 CONFIG_SYS_NAND_U_BOOT_START
2962 Entry point in loaded image to jump to
2964 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2965 Define this if you need to first read the OOB and then the
2966 data. This is used for example on davinci plattforms.
2968 CONFIG_SPL_OMAP3_ID_NAND
2969 Support for an OMAP3-specific set of functions to return the
2970 ID and MFR of the first attached NAND chip, if present.
2972 CONFIG_SPL_SERIAL_SUPPORT
2973 Support for drivers/serial/libserial.o in SPL binary
2975 CONFIG_SPL_SPI_FLASH_SUPPORT
2976 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2978 CONFIG_SPL_SPI_SUPPORT
2979 Support for drivers/spi/libspi.o in SPL binary
2981 CONFIG_SPL_RAM_DEVICE
2982 Support for running image already present in ram, in SPL binary
2984 CONFIG_SPL_LIBGENERIC_SUPPORT
2985 Support for lib/libgeneric.o in SPL binary
2988 Image offset to which the SPL should be padded before appending
2989 the SPL payload. By default, this is defined as
2990 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2991 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2992 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2995 Final target image containing SPL and payload. Some SPLs
2996 use an arch-specific makefile fragment instead, for
2997 example if more than one image needs to be produced.
2999 CONFIG_FIT_SPL_PRINT
3000 Printing information about a FIT image adds quite a bit of
3001 code to SPL. So this is normally disabled in SPL. Use this
3002 option to re-enable it. This will affect the output of the
3003 bootm command when booting a FIT image.
3008 [so far only for SMDK2400 boards]
3010 - Modem support enable:
3011 CONFIG_MODEM_SUPPORT
3013 - RTS/CTS Flow control enable:
3016 - Modem debug support:
3017 CONFIG_MODEM_SUPPORT_DEBUG
3019 Enables debugging stuff (char screen[1024], dbg())
3020 for modem support. Useful only with BDI2000.
3022 - Interrupt support (PPC):
3024 There are common interrupt_init() and timer_interrupt()
3025 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3026 for CPU specific initialization. interrupt_init_cpu()
3027 should set decrementer_count to appropriate value. If
3028 CPU resets decrementer automatically after interrupt
3029 (ppc4xx) it should set decrementer_count to zero.
3030 timer_interrupt() calls timer_interrupt_cpu() for CPU
3031 specific handling. If board has watchdog / status_led
3032 / other_activity_monitor it works automatically from
3033 general timer_interrupt().
3037 In the target system modem support is enabled when a
3038 specific key (key combination) is pressed during
3039 power-on. Otherwise U-Boot will boot normally
3040 (autoboot). The key_pressed() function is called from
3041 board_init(). Currently key_pressed() is a dummy
3042 function, returning 1 and thus enabling modem
3045 If there are no modem init strings in the
3046 environment, U-Boot proceed to autoboot; the
3047 previous output (banner, info printfs) will be
3050 See also: doc/README.Modem
3052 Board initialization settings:
3053 ------------------------------
3055 During Initialization u-boot calls a number of board specific functions
3056 to allow the preparation of board specific prerequisites, e.g. pin setup
3057 before drivers are initialized. To enable these callbacks the
3058 following configuration macros have to be defined. Currently this is
3059 architecture specific, so please check arch/your_architecture/lib/board.c
3060 typically in board_init_f() and board_init_r().
3062 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3063 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3064 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3065 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3067 Configuration Settings:
3068 -----------------------
3070 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3071 undefine this when you're short of memory.
3073 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3074 width of the commands listed in the 'help' command output.
3076 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3077 prompt for user input.
3079 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3081 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3083 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3085 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3086 the application (usually a Linux kernel) when it is
3089 - CONFIG_SYS_BAUDRATE_TABLE:
3090 List of legal baudrate settings for this board.
3092 - CONFIG_SYS_CONSOLE_INFO_QUIET
3093 Suppress display of console information at boot.
3095 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3096 If the board specific function
3097 extern int overwrite_console (void);
3098 returns 1, the stdin, stderr and stdout are switched to the
3099 serial port, else the settings in the environment are used.
3101 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3102 Enable the call to overwrite_console().
3104 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3105 Enable overwrite of previous console environment settings.
3107 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3108 Begin and End addresses of the area used by the
3111 - CONFIG_SYS_ALT_MEMTEST:
3112 Enable an alternate, more extensive memory test.
3114 - CONFIG_SYS_MEMTEST_SCRATCH:
3115 Scratch address used by the alternate memory test
3116 You only need to set this if address zero isn't writeable
3118 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
3119 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3120 this specified memory area will get subtracted from the top
3121 (end) of RAM and won't get "touched" at all by U-Boot. By
3122 fixing up gd->ram_size the Linux kernel should gets passed
3123 the now "corrected" memory size and won't touch it either.
3124 This should work for arch/ppc and arch/powerpc. Only Linux
3125 board ports in arch/powerpc with bootwrapper support that
3126 recalculate the memory size from the SDRAM controller setup
3127 will have to get fixed in Linux additionally.
3129 This option can be used as a workaround for the 440EPx/GRx
3130 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3133 WARNING: Please make sure that this value is a multiple of
3134 the Linux page size (normally 4k). If this is not the case,
3135 then the end address of the Linux memory will be located at a
3136 non page size aligned address and this could cause major
3139 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3140 Enable temporary baudrate change while serial download
3142 - CONFIG_SYS_SDRAM_BASE:
3143 Physical start address of SDRAM. _Must_ be 0 here.
3145 - CONFIG_SYS_MBIO_BASE:
3146 Physical start address of Motherboard I/O (if using a
3149 - CONFIG_SYS_FLASH_BASE:
3150 Physical start address of Flash memory.
3152 - CONFIG_SYS_MONITOR_BASE:
3153 Physical start address of boot monitor code (set by
3154 make config files to be same as the text base address
3155 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3156 CONFIG_SYS_FLASH_BASE when booting from flash.
3158 - CONFIG_SYS_MONITOR_LEN:
3159 Size of memory reserved for monitor code, used to
3160 determine _at_compile_time_ (!) if the environment is
3161 embedded within the U-Boot image, or in a separate
3164 - CONFIG_SYS_MALLOC_LEN:
3165 Size of DRAM reserved for malloc() use.
3167 - CONFIG_SYS_BOOTM_LEN:
3168 Normally compressed uImages are limited to an
3169 uncompressed size of 8 MBytes. If this is not enough,
3170 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3171 to adjust this setting to your needs.
3173 - CONFIG_SYS_BOOTMAPSZ:
3174 Maximum size of memory mapped by the startup code of
3175 the Linux kernel; all data that must be processed by
3176 the Linux kernel (bd_info, boot arguments, FDT blob if
3177 used) must be put below this limit, unless "bootm_low"
3178 enviroment variable is defined and non-zero. In such case
3179 all data for the Linux kernel must be between "bootm_low"
3180 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3181 variable "bootm_mapsize" will override the value of
3182 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3183 then the value in "bootm_size" will be used instead.
3185 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3186 Enable initrd_high functionality. If defined then the
3187 initrd_high feature is enabled and the bootm ramdisk subcommand
3190 - CONFIG_SYS_BOOT_GET_CMDLINE:
3191 Enables allocating and saving kernel cmdline in space between
3192 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3194 - CONFIG_SYS_BOOT_GET_KBD:
3195 Enables allocating and saving a kernel copy of the bd_info in
3196 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3198 - CONFIG_SYS_MAX_FLASH_BANKS:
3199 Max number of Flash memory banks
3201 - CONFIG_SYS_MAX_FLASH_SECT:
3202 Max number of sectors on a Flash chip
3204 - CONFIG_SYS_FLASH_ERASE_TOUT:
3205 Timeout for Flash erase operations (in ms)
3207 - CONFIG_SYS_FLASH_WRITE_TOUT:
3208 Timeout for Flash write operations (in ms)
3210 - CONFIG_SYS_FLASH_LOCK_TOUT
3211 Timeout for Flash set sector lock bit operation (in ms)
3213 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3214 Timeout for Flash clear lock bits operation (in ms)
3216 - CONFIG_SYS_FLASH_PROTECTION
3217 If defined, hardware flash sectors protection is used
3218 instead of U-Boot software protection.
3220 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3222 Enable TFTP transfers directly to flash memory;
3223 without this option such a download has to be
3224 performed in two steps: (1) download to RAM, and (2)
3225 copy from RAM to flash.
3227 The two-step approach is usually more reliable, since
3228 you can check if the download worked before you erase
3229 the flash, but in some situations (when system RAM is
3230 too limited to allow for a temporary copy of the
3231 downloaded image) this option may be very useful.
3233 - CONFIG_SYS_FLASH_CFI:
3234 Define if the flash driver uses extra elements in the
3235 common flash structure for storing flash geometry.
3237 - CONFIG_FLASH_CFI_DRIVER
3238 This option also enables the building of the cfi_flash driver
3239 in the drivers directory
3241 - CONFIG_FLASH_CFI_MTD
3242 This option enables the building of the cfi_mtd driver
3243 in the drivers directory. The driver exports CFI flash
3246 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3247 Use buffered writes to flash.
3249 - CONFIG_FLASH_SPANSION_S29WS_N
3250 s29ws-n MirrorBit flash has non-standard addresses for buffered
3253 - CONFIG_SYS_FLASH_QUIET_TEST
3254 If this option is defined, the common CFI flash doesn't
3255 print it's warning upon not recognized FLASH banks. This
3256 is useful, if some of the configured banks are only
3257 optionally available.
3259 - CONFIG_FLASH_SHOW_PROGRESS
3260 If defined (must be an integer), print out countdown
3261 digits and dots. Recommended value: 45 (9..1) for 80
3262 column displays, 15 (3..1) for 40 column displays.
3264 - CONFIG_FLASH_VERIFY
3265 If defined, the content of the flash (destination) is compared
3266 against the source after the write operation. An error message
3267 will be printed when the contents are not identical.
3268 Please note that this option is useless in nearly all cases,
3269 since such flash programming errors usually are detected earlier
3270 while unprotecting/erasing/programming. Please only enable
3271 this option if you really know what you are doing.
3273 - CONFIG_SYS_RX_ETH_BUFFER:
3274 Defines the number of Ethernet receive buffers. On some
3275 Ethernet controllers it is recommended to set this value
3276 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3277 buffers can be full shortly after enabling the interface
3278 on high Ethernet traffic.
3279 Defaults to 4 if not defined.
3281 - CONFIG_ENV_MAX_ENTRIES
3283 Maximum number of entries in the hash table that is used
3284 internally to store the environment settings. The default
3285 setting is supposed to be generous and should work in most
3286 cases. This setting can be used to tune behaviour; see
3287 lib/hashtable.c for details.
3289 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3290 - CONFIG_ENV_FLAGS_LIST_STATIC
3291 Enable validation of the values given to enviroment variables when
3292 calling env set. Variables can be restricted to only decimal,
3293 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3294 the variables can also be restricted to IP address or MAC address.
3296 The format of the list is:
3297 type_attribute = [s|d|x|b|i|m]
3298 access_atribute = [a|r|o|c]
3299 attributes = type_attribute[access_atribute]
3300 entry = variable_name[:attributes]
3303 The type attributes are:
3304 s - String (default)
3307 b - Boolean ([1yYtT|0nNfF])
3311 The access attributes are:
3317 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3318 Define this to a list (string) to define the ".flags"
3319 envirnoment variable in the default or embedded environment.
3321 - CONFIG_ENV_FLAGS_LIST_STATIC
3322 Define this to a list (string) to define validation that
3323 should be done if an entry is not found in the ".flags"
3324 environment variable. To override a setting in the static
3325 list, simply add an entry for the same variable name to the
3328 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3329 If defined, don't allow the -f switch to env set override variable
3332 - CONFIG_SYS_GENERIC_BOARD
3333 This selects the architecture-generic board system instead of the
3334 architecture-specific board files. It is intended to move boards
3335 to this new framework over time. Defining this will disable the
3336 arch/foo/lib/board.c file and use common/board_f.c and
3337 common/board_r.c instead. To use this option your architecture
3338 must support it (i.e. must define __HAVE_ARCH_GENERIC_BOARD in
3339 its config.mk file). If you find problems enabling this option on
3340 your board please report the problem and send patches!
3342 - CONFIG_SYS_SYM_OFFSETS
3343 This is set by architectures that use offsets for link symbols
3344 instead of absolute values. So bss_start is obtained using an
3345 offset _bss_start_ofs from CONFIG_SYS_TEXT_BASE, rather than
3346 directly. You should not need to touch this setting.
3349 The following definitions that deal with the placement and management
3350 of environment data (variable area); in general, we support the
3351 following configurations:
3353 - CONFIG_BUILD_ENVCRC:
3355 Builds up envcrc with the target environment so that external utils
3356 may easily extract it and embed it in final U-Boot images.
3358 - CONFIG_ENV_IS_IN_FLASH:
3360 Define this if the environment is in flash memory.
3362 a) The environment occupies one whole flash sector, which is
3363 "embedded" in the text segment with the U-Boot code. This
3364 happens usually with "bottom boot sector" or "top boot
3365 sector" type flash chips, which have several smaller
3366 sectors at the start or the end. For instance, such a
3367 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3368 such a case you would place the environment in one of the
3369 4 kB sectors - with U-Boot code before and after it. With
3370 "top boot sector" type flash chips, you would put the
3371 environment in one of the last sectors, leaving a gap
3372 between U-Boot and the environment.
3374 - CONFIG_ENV_OFFSET:
3376 Offset of environment data (variable area) to the
3377 beginning of flash memory; for instance, with bottom boot
3378 type flash chips the second sector can be used: the offset
3379 for this sector is given here.
3381 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3385 This is just another way to specify the start address of
3386 the flash sector containing the environment (instead of
3389 - CONFIG_ENV_SECT_SIZE:
3391 Size of the sector containing the environment.
3394 b) Sometimes flash chips have few, equal sized, BIG sectors.
3395 In such a case you don't want to spend a whole sector for
3400 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3401 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3402 of this flash sector for the environment. This saves
3403 memory for the RAM copy of the environment.
3405 It may also save flash memory if you decide to use this
3406 when your environment is "embedded" within U-Boot code,
3407 since then the remainder of the flash sector could be used
3408 for U-Boot code. It should be pointed out that this is
3409 STRONGLY DISCOURAGED from a robustness point of view:
3410 updating the environment in flash makes it always
3411 necessary to erase the WHOLE sector. If something goes
3412 wrong before the contents has been restored from a copy in
3413 RAM, your target system will be dead.
3415 - CONFIG_ENV_ADDR_REDUND
3416 CONFIG_ENV_SIZE_REDUND
3418 These settings describe a second storage area used to hold
3419 a redundant copy of the environment data, so that there is
3420 a valid backup copy in case there is a power failure during
3421 a "saveenv" operation.
3423 BE CAREFUL! Any changes to the flash layout, and some changes to the
3424 source code will make it necessary to adapt <board>/u-boot.lds*
3428 - CONFIG_ENV_IS_IN_NVRAM:
3430 Define this if you have some non-volatile memory device
3431 (NVRAM, battery buffered SRAM) which you want to use for the
3437 These two #defines are used to determine the memory area you
3438 want to use for environment. It is assumed that this memory
3439 can just be read and written to, without any special
3442 BE CAREFUL! The first access to the environment happens quite early
3443 in U-Boot initalization (when we try to get the setting of for the
3444 console baudrate). You *MUST* have mapped your NVRAM area then, or
3447 Please note that even with NVRAM we still use a copy of the
3448 environment in RAM: we could work on NVRAM directly, but we want to
3449 keep settings there always unmodified except somebody uses "saveenv"
3450 to save the current settings.
3453 - CONFIG_ENV_IS_IN_EEPROM:
3455 Use this if you have an EEPROM or similar serial access
3456 device and a driver for it.
3458 - CONFIG_ENV_OFFSET:
3461 These two #defines specify the offset and size of the
3462 environment area within the total memory of your EEPROM.
3464 - CONFIG_SYS_I2C_EEPROM_ADDR:
3465 If defined, specified the chip address of the EEPROM device.
3466 The default address is zero.
3468 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3469 If defined, the number of bits used to address bytes in a
3470 single page in the EEPROM device. A 64 byte page, for example
3471 would require six bits.
3473 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3474 If defined, the number of milliseconds to delay between
3475 page writes. The default is zero milliseconds.
3477 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3478 The length in bytes of the EEPROM memory array address. Note
3479 that this is NOT the chip address length!
3481 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3482 EEPROM chips that implement "address overflow" are ones
3483 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3484 address and the extra bits end up in the "chip address" bit
3485 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3488 Note that we consider the length of the address field to
3489 still be one byte because the extra address bits are hidden
3490 in the chip address.
3492 - CONFIG_SYS_EEPROM_SIZE:
3493 The size in bytes of the EEPROM device.
3495 - CONFIG_ENV_EEPROM_IS_ON_I2C
3496 define this, if you have I2C and SPI activated, and your
3497 EEPROM, which holds the environment, is on the I2C bus.
3499 - CONFIG_I2C_ENV_EEPROM_BUS
3500 if you have an Environment on an EEPROM reached over
3501 I2C muxes, you can define here, how to reach this
3502 EEPROM. For example:
3504 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3506 EEPROM which holds the environment, is reached over
3507 a pca9547 i2c mux with address 0x70, channel 3.
3509 - CONFIG_ENV_IS_IN_DATAFLASH:
3511 Define this if you have a DataFlash memory device which you
3512 want to use for the environment.
3514 - CONFIG_ENV_OFFSET:
3518 These three #defines specify the offset and size of the
3519 environment area within the total memory of your DataFlash placed
3520 at the specified address.
3522 - CONFIG_ENV_IS_IN_REMOTE:
3524 Define this if you have a remote memory space which you
3525 want to use for the local device's environment.
3530 These two #defines specify the address and size of the
3531 environment area within the remote memory space. The
3532 local device can get the environment from remote memory
3533 space by SRIO or PCIE links.
3535 BE CAREFUL! For some special cases, the local device can not use
3536 "saveenv" command. For example, the local device will get the
3537 environment stored in a remote NOR flash by SRIO or PCIE link,
3538 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3540 - CONFIG_ENV_IS_IN_NAND:
3542 Define this if you have a NAND device which you want to use
3543 for the environment.
3545 - CONFIG_ENV_OFFSET:
3548 These two #defines specify the offset and size of the environment
3549 area within the first NAND device. CONFIG_ENV_OFFSET must be
3550 aligned to an erase block boundary.
3552 - CONFIG_ENV_OFFSET_REDUND (optional):
3554 This setting describes a second storage area of CONFIG_ENV_SIZE
3555 size used to hold a redundant copy of the environment data, so
3556 that there is a valid backup copy in case there is a power failure
3557 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3558 aligned to an erase block boundary.
3560 - CONFIG_ENV_RANGE (optional):
3562 Specifies the length of the region in which the environment
3563 can be written. This should be a multiple of the NAND device's
3564 block size. Specifying a range with more erase blocks than
3565 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3566 the range to be avoided.
3568 - CONFIG_ENV_OFFSET_OOB (optional):
3570 Enables support for dynamically retrieving the offset of the
3571 environment from block zero's out-of-band data. The
3572 "nand env.oob" command can be used to record this offset.
3573 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3574 using CONFIG_ENV_OFFSET_OOB.
3576 - CONFIG_NAND_ENV_DST
3578 Defines address in RAM to which the nand_spl code should copy the
3579 environment. If redundant environment is used, it will be copied to
3580 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3582 - CONFIG_ENV_IS_IN_UBI:
3584 Define this if you have an UBI volume that you want to use for the
3585 environment. This has the benefit of wear-leveling the environment
3586 accesses, which is important on NAND.
3588 - CONFIG_ENV_UBI_PART:
3590 Define this to a string that is the mtd partition containing the UBI.
3592 - CONFIG_ENV_UBI_VOLUME:
3594 Define this to the name of the volume that you want to store the
3597 - CONFIG_ENV_UBI_VOLUME_REDUND:
3599 Define this to the name of another volume to store a second copy of
3600 the environment in. This will enable redundant environments in UBI.
3601 It is assumed that both volumes are in the same MTD partition.
3603 - CONFIG_UBI_SILENCE_MSG
3604 - CONFIG_UBIFS_SILENCE_MSG
3606 You will probably want to define these to avoid a really noisy system
3607 when storing the env in UBI.
3609 - CONFIG_SYS_SPI_INIT_OFFSET
3611 Defines offset to the initial SPI buffer area in DPRAM. The
3612 area is used at an early stage (ROM part) if the environment
3613 is configured to reside in the SPI EEPROM: We need a 520 byte
3614 scratch DPRAM area. It is used between the two initialization
3615 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3616 to be a good choice since it makes it far enough from the
3617 start of the data area as well as from the stack pointer.
3619 Please note that the environment is read-only until the monitor
3620 has been relocated to RAM and a RAM copy of the environment has been
3621 created; also, when using EEPROM you will have to use getenv_f()
3622 until then to read environment variables.
3624 The environment is protected by a CRC32 checksum. Before the monitor
3625 is relocated into RAM, as a result of a bad CRC you will be working
3626 with the compiled-in default environment - *silently*!!! [This is
3627 necessary, because the first environment variable we need is the
3628 "baudrate" setting for the console - if we have a bad CRC, we don't
3629 have any device yet where we could complain.]
3631 Note: once the monitor has been relocated, then it will complain if
3632 the default environment is used; a new CRC is computed as soon as you
3633 use the "saveenv" command to store a valid environment.
3635 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3636 Echo the inverted Ethernet link state to the fault LED.
3638 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3639 also needs to be defined.
3641 - CONFIG_SYS_FAULT_MII_ADDR:
3642 MII address of the PHY to check for the Ethernet link state.
3644 - CONFIG_NS16550_MIN_FUNCTIONS:
3645 Define this if you desire to only have use of the NS16550_init
3646 and NS16550_putc functions for the serial driver located at
3647 drivers/serial/ns16550.c. This option is useful for saving
3648 space for already greatly restricted images, including but not
3649 limited to NAND_SPL configurations.
3651 - CONFIG_DISPLAY_BOARDINFO
3652 Display information about the board that U-Boot is running on
3653 when U-Boot starts up. The board function checkboard() is called
3656 - CONFIG_DISPLAY_BOARDINFO_LATE
3657 Similar to the previous option, but display this information
3658 later, once stdio is running and output goes to the LCD, if
3661 Low Level (hardware related) configuration options:
3662 ---------------------------------------------------
3664 - CONFIG_SYS_CACHELINE_SIZE:
3665 Cache Line Size of the CPU.
3667 - CONFIG_SYS_DEFAULT_IMMR:
3668 Default address of the IMMR after system reset.
3670 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3671 and RPXsuper) to be able to adjust the position of
3672 the IMMR register after a reset.
3674 - CONFIG_SYS_CCSRBAR_DEFAULT:
3675 Default (power-on reset) physical address of CCSR on Freescale
3678 - CONFIG_SYS_CCSRBAR:
3679 Virtual address of CCSR. On a 32-bit build, this is typically
3680 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3682 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3683 for cross-platform code that uses that macro instead.
3685 - CONFIG_SYS_CCSRBAR_PHYS:
3686 Physical address of CCSR. CCSR can be relocated to a new
3687 physical address, if desired. In this case, this macro should
3688 be set to that address. Otherwise, it should be set to the
3689 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3690 is typically relocated on 36-bit builds. It is recommended
3691 that this macro be defined via the _HIGH and _LOW macros:
3693 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3694 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3696 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3697 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3698 either 0 (32-bit build) or 0xF (36-bit build). 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_CCSRBAR_PHYS_LOW:
3703 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3704 used in assembly code, so it must not contain typecasts or
3705 integer size suffixes (e.g. "ULL").
3707 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3708 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3709 forced to a value that ensures that CCSR is not relocated.
3711 - Floppy Disk Support:
3712 CONFIG_SYS_FDC_DRIVE_NUMBER
3714 the default drive number (default value 0)
3716 CONFIG_SYS_ISA_IO_STRIDE
3718 defines the spacing between FDC chipset registers
3721 CONFIG_SYS_ISA_IO_OFFSET
3723 defines the offset of register from address. It
3724 depends on which part of the data bus is connected to
3725 the FDC chipset. (default value 0)
3727 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3728 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3731 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3732 fdc_hw_init() is called at the beginning of the FDC
3733 setup. fdc_hw_init() must be provided by the board
3734 source code. It is used to make hardware dependant
3738 Most IDE controllers were designed to be connected with PCI
3739 interface. Only few of them were designed for AHB interface.
3740 When software is doing ATA command and data transfer to
3741 IDE devices through IDE-AHB controller, some additional
3742 registers accessing to these kind of IDE-AHB controller
3745 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3746 DO NOT CHANGE unless you know exactly what you're
3747 doing! (11-4) [MPC8xx/82xx systems only]
3749 - CONFIG_SYS_INIT_RAM_ADDR:
3751 Start address of memory area that can be used for
3752 initial data and stack; please note that this must be
3753 writable memory that is working WITHOUT special
3754 initialization, i. e. you CANNOT use normal RAM which
3755 will become available only after programming the
3756 memory controller and running certain initialization
3759 U-Boot uses the following memory types:
3760 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3761 - MPC824X: data cache
3762 - PPC4xx: data cache
3764 - CONFIG_SYS_GBL_DATA_OFFSET:
3766 Offset of the initial data structure in the memory
3767 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3768 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3769 data is located at the end of the available space
3770 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3771 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3772 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3773 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3776 On the MPC824X (or other systems that use the data
3777 cache for initial memory) the address chosen for
3778 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3779 point to an otherwise UNUSED address space between
3780 the top of RAM and the start of the PCI space.
3782 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3784 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3786 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3788 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3790 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3792 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3794 - CONFIG_SYS_OR_TIMING_SDRAM:
3797 - CONFIG_SYS_MAMR_PTA:
3798 periodic timer for refresh
3800 - CONFIG_SYS_DER: Debug Event Register (37-47)
3802 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3803 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3804 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3805 CONFIG_SYS_BR1_PRELIM:
3806 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3808 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3809 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3810 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3811 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3813 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3814 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3815 Machine Mode Register and Memory Periodic Timer
3816 Prescaler definitions (SDRAM timing)
3818 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3819 enable I2C microcode relocation patch (MPC8xx);
3820 define relocation offset in DPRAM [DSP2]
3822 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3823 enable SMC microcode relocation patch (MPC8xx);
3824 define relocation offset in DPRAM [SMC1]
3826 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3827 enable SPI microcode relocation patch (MPC8xx);
3828 define relocation offset in DPRAM [SCC4]
3830 - CONFIG_SYS_USE_OSCCLK:
3831 Use OSCM clock mode on MBX8xx board. Be careful,
3832 wrong setting might damage your board. Read
3833 doc/README.MBX before setting this variable!
3835 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3836 Offset of the bootmode word in DPRAM used by post
3837 (Power On Self Tests). This definition overrides
3838 #define'd default value in commproc.h resp.
3841 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3842 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3843 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3844 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3845 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3846 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3847 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3848 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3849 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3851 - CONFIG_PCI_DISABLE_PCIE:
3852 Disable PCI-Express on systems where it is supported but not
3855 - CONFIG_PCI_ENUM_ONLY
3856 Only scan through and get the devices on the busses.
3857 Don't do any setup work, presumably because someone or
3858 something has already done it, and we don't need to do it
3859 a second time. Useful for platforms that are pre-booted
3860 by coreboot or similar.
3863 Chip has SRIO or not
3866 Board has SRIO 1 port available
3869 Board has SRIO 2 port available
3871 - CONFIG_SYS_SRIOn_MEM_VIRT:
3872 Virtual Address of SRIO port 'n' memory region
3874 - CONFIG_SYS_SRIOn_MEM_PHYS:
3875 Physical Address of SRIO port 'n' memory region
3877 - CONFIG_SYS_SRIOn_MEM_SIZE:
3878 Size of SRIO port 'n' memory region
3880 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3881 Defined to tell the NAND controller that the NAND chip is using
3883 Not all NAND drivers use this symbol.
3884 Example of drivers that use it:
3885 - drivers/mtd/nand/ndfc.c
3886 - drivers/mtd/nand/mxc_nand.c
3888 - CONFIG_SYS_NDFC_EBC0_CFG
3889 Sets the EBC0_CFG register for the NDFC. If not defined
3890 a default value will be used.
3893 Get DDR timing information from an I2C EEPROM. Common
3894 with pluggable memory modules such as SODIMMs
3897 I2C address of the SPD EEPROM
3899 - CONFIG_SYS_SPD_BUS_NUM
3900 If SPD EEPROM is on an I2C bus other than the first
3901 one, specify here. Note that the value must resolve
3902 to something your driver can deal with.
3904 - CONFIG_SYS_DDR_RAW_TIMING
3905 Get DDR timing information from other than SPD. Common with
3906 soldered DDR chips onboard without SPD. DDR raw timing
3907 parameters are extracted from datasheet and hard-coded into
3908 header files or board specific files.
3910 - CONFIG_FSL_DDR_INTERACTIVE
3911 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3913 - CONFIG_SYS_83XX_DDR_USES_CS0
3914 Only for 83xx systems. If specified, then DDR should
3915 be configured using CS0 and CS1 instead of CS2 and CS3.
3917 - CONFIG_ETHER_ON_FEC[12]
3918 Define to enable FEC[12] on a 8xx series processor.
3920 - CONFIG_FEC[12]_PHY
3921 Define to the hardcoded PHY address which corresponds
3922 to the given FEC; i. e.
3923 #define CONFIG_FEC1_PHY 4
3924 means that the PHY with address 4 is connected to FEC1
3926 When set to -1, means to probe for first available.
3928 - CONFIG_FEC[12]_PHY_NORXERR
3929 The PHY does not have a RXERR line (RMII only).
3930 (so program the FEC to ignore it).
3933 Enable RMII mode for all FECs.
3934 Note that this is a global option, we can't
3935 have one FEC in standard MII mode and another in RMII mode.
3937 - CONFIG_CRC32_VERIFY
3938 Add a verify option to the crc32 command.
3941 => crc32 -v <address> <count> <crc32>
3943 Where address/count indicate a memory area
3944 and crc32 is the correct crc32 which the
3948 Add the "loopw" memory command. This only takes effect if
3949 the memory commands are activated globally (CONFIG_CMD_MEM).
3952 Add the "mdc" and "mwc" memory commands. These are cyclic
3957 This command will print 4 bytes (10,11,12,13) each 500 ms.
3959 => mwc.l 100 12345678 10
3960 This command will write 12345678 to address 100 all 10 ms.
3962 This only takes effect if the memory commands are activated
3963 globally (CONFIG_CMD_MEM).
3965 - CONFIG_SKIP_LOWLEVEL_INIT
3966 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3967 low level initializations (like setting up the memory
3968 controller) are omitted and/or U-Boot does not
3969 relocate itself into RAM.
3971 Normally this variable MUST NOT be defined. The only
3972 exception is when U-Boot is loaded (to RAM) by some
3973 other boot loader or by a debugger which performs
3974 these initializations itself.
3977 Modifies the behaviour of start.S when compiling a loader
3978 that is executed before the actual U-Boot. E.g. when
3979 compiling a NAND SPL.
3981 - CONFIG_ARCH_MAP_SYSMEM
3982 Generally U-Boot (and in particular the md command) uses
3983 effective address. It is therefore not necessary to regard
3984 U-Boot address as virtual addresses that need to be translated
3985 to physical addresses. However, sandbox requires this, since
3986 it maintains its own little RAM buffer which contains all
3987 addressable memory. This option causes some memory accesses
3988 to be mapped through map_sysmem() / unmap_sysmem().
3990 - CONFIG_USE_ARCH_MEMCPY
3991 CONFIG_USE_ARCH_MEMSET
3992 If these options are used a optimized version of memcpy/memset will
3993 be used if available. These functions may be faster under some
3994 conditions but may increase the binary size.
3996 - CONFIG_X86_RESET_VECTOR
3997 If defined, the x86 reset vector code is included. This is not
3998 needed when U-Boot is running from Coreboot.
4001 Defines the MPU clock speed (in MHz).
4003 NOTE : currently only supported on AM335x platforms.
4005 Freescale QE/FMAN Firmware Support:
4006 -----------------------------------
4008 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4009 loading of "firmware", which is encoded in the QE firmware binary format.
4010 This firmware often needs to be loaded during U-Boot booting, so macros
4011 are used to identify the storage device (NOR flash, SPI, etc) and the address
4014 - CONFIG_SYS_QE_FMAN_FW_ADDR
4015 The address in the storage device where the firmware is located. The
4016 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4019 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4020 The maximum possible size of the firmware. The firmware binary format
4021 has a field that specifies the actual size of the firmware, but it
4022 might not be possible to read any part of the firmware unless some
4023 local storage is allocated to hold the entire firmware first.
4025 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4026 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4027 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4028 virtual address in NOR flash.
4030 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4031 Specifies that QE/FMAN firmware is located in NAND flash.
4032 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4034 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4035 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4036 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4038 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4039 Specifies that QE/FMAN firmware is located on the primary SPI
4040 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4042 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4043 Specifies that QE/FMAN firmware is located in the remote (master)
4044 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4045 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4046 window->master inbound window->master LAW->the ucode address in
4047 master's memory space.
4049 Building the Software:
4050 ======================
4052 Building U-Boot has been tested in several native build environments
4053 and in many different cross environments. Of course we cannot support
4054 all possibly existing versions of cross development tools in all
4055 (potentially obsolete) versions. In case of tool chain problems we
4056 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4057 which is extensively used to build and test U-Boot.
4059 If you are not using a native environment, it is assumed that you
4060 have GNU cross compiling tools available in your path. In this case,
4061 you must set the environment variable CROSS_COMPILE in your shell.
4062 Note that no changes to the Makefile or any other source files are
4063 necessary. For example using the ELDK on a 4xx CPU, please enter:
4065 $ CROSS_COMPILE=ppc_4xx-
4066 $ export CROSS_COMPILE
4068 Note: If you wish to generate Windows versions of the utilities in
4069 the tools directory you can use the MinGW toolchain
4070 (http://www.mingw.org). Set your HOST tools to the MinGW
4071 toolchain and execute 'make tools'. For example:
4073 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4075 Binaries such as tools/mkimage.exe will be created which can
4076 be executed on computers running Windows.
4078 U-Boot is intended to be simple to build. After installing the
4079 sources you must configure U-Boot for one specific board type. This
4084 where "NAME_config" is the name of one of the existing configu-
4085 rations; see boards.cfg for supported names.
4087 Note: for some board special configuration names may exist; check if
4088 additional information is available from the board vendor; for
4089 instance, the TQM823L systems are available without (standard)
4090 or with LCD support. You can select such additional "features"
4091 when choosing the configuration, i. e.
4094 - will configure for a plain TQM823L, i. e. no LCD support
4096 make TQM823L_LCD_config
4097 - will configure for a TQM823L with U-Boot console on LCD
4102 Finally, type "make all", and you should get some working U-Boot
4103 images ready for download to / installation on your system:
4105 - "u-boot.bin" is a raw binary image
4106 - "u-boot" is an image in ELF binary format
4107 - "u-boot.srec" is in Motorola S-Record format
4109 By default the build is performed locally and the objects are saved
4110 in the source directory. One of the two methods can be used to change
4111 this behavior and build U-Boot to some external directory:
4113 1. Add O= to the make command line invocations:
4115 make O=/tmp/build distclean
4116 make O=/tmp/build NAME_config
4117 make O=/tmp/build all
4119 2. Set environment variable BUILD_DIR to point to the desired location:
4121 export BUILD_DIR=/tmp/build
4126 Note that the command line "O=" setting overrides the BUILD_DIR environment
4130 Please be aware that the Makefiles assume you are using GNU make, so
4131 for instance on NetBSD you might need to use "gmake" instead of
4135 If the system board that you have is not listed, then you will need
4136 to port U-Boot to your hardware platform. To do this, follow these
4139 1. Add a new configuration option for your board to the toplevel
4140 "boards.cfg" file, using the existing entries as examples.
4141 Follow the instructions there to keep the boards in order.
4142 2. Create a new directory to hold your board specific code. Add any
4143 files you need. In your board directory, you will need at least
4144 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
4145 3. Create a new configuration file "include/configs/<board>.h" for
4147 3. If you're porting U-Boot to a new CPU, then also create a new
4148 directory to hold your CPU specific code. Add any files you need.
4149 4. Run "make <board>_config" with your new name.
4150 5. Type "make", and you should get a working "u-boot.srec" file
4151 to be installed on your target system.
4152 6. Debug and solve any problems that might arise.
4153 [Of course, this last step is much harder than it sounds.]
4156 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4157 ==============================================================
4159 If you have modified U-Boot sources (for instance added a new board
4160 or support for new devices, a new CPU, etc.) you are expected to
4161 provide feedback to the other developers. The feedback normally takes
4162 the form of a "patch", i. e. a context diff against a certain (latest
4163 official or latest in the git repository) version of U-Boot sources.
4165 But before you submit such a patch, please verify that your modifi-
4166 cation did not break existing code. At least make sure that *ALL* of
4167 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4168 just run the "MAKEALL" script, which will configure and build U-Boot
4169 for ALL supported system. Be warned, this will take a while. You can
4170 select which (cross) compiler to use by passing a `CROSS_COMPILE'
4171 environment variable to the script, i. e. to use the ELDK cross tools
4174 CROSS_COMPILE=ppc_8xx- MAKEALL
4176 or to build on a native PowerPC system you can type
4178 CROSS_COMPILE=' ' MAKEALL
4180 When using the MAKEALL script, the default behaviour is to build
4181 U-Boot in the source directory. This location can be changed by
4182 setting the BUILD_DIR environment variable. Also, for each target
4183 built, the MAKEALL script saves two log files (<target>.ERR and
4184 <target>.MAKEALL) in the <source dir>/LOG directory. This default
4185 location can be changed by setting the MAKEALL_LOGDIR environment
4186 variable. For example:
4188 export BUILD_DIR=/tmp/build
4189 export MAKEALL_LOGDIR=/tmp/log
4190 CROSS_COMPILE=ppc_8xx- MAKEALL
4192 With the above settings build objects are saved in the /tmp/build,
4193 log files are saved in the /tmp/log and the source tree remains clean
4194 during the whole build process.
4197 See also "U-Boot Porting Guide" below.
4200 Monitor Commands - Overview:
4201 ============================
4203 go - start application at address 'addr'
4204 run - run commands in an environment variable
4205 bootm - boot application image from memory
4206 bootp - boot image via network using BootP/TFTP protocol
4207 bootz - boot zImage from memory
4208 tftpboot- boot image via network using TFTP protocol
4209 and env variables "ipaddr" and "serverip"
4210 (and eventually "gatewayip")
4211 tftpput - upload a file via network using TFTP protocol
4212 rarpboot- boot image via network using RARP/TFTP protocol
4213 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4214 loads - load S-Record file over serial line
4215 loadb - load binary file over serial line (kermit mode)
4217 mm - memory modify (auto-incrementing)
4218 nm - memory modify (constant address)
4219 mw - memory write (fill)
4221 cmp - memory compare
4222 crc32 - checksum calculation
4223 i2c - I2C sub-system
4224 sspi - SPI utility commands
4225 base - print or set address offset
4226 printenv- print environment variables
4227 setenv - set environment variables
4228 saveenv - save environment variables to persistent storage
4229 protect - enable or disable FLASH write protection
4230 erase - erase FLASH memory
4231 flinfo - print FLASH memory information
4232 nand - NAND memory operations (see doc/README.nand)
4233 bdinfo - print Board Info structure
4234 iminfo - print header information for application image
4235 coninfo - print console devices and informations
4236 ide - IDE sub-system
4237 loop - infinite loop on address range
4238 loopw - infinite write loop on address range
4239 mtest - simple RAM test
4240 icache - enable or disable instruction cache
4241 dcache - enable or disable data cache
4242 reset - Perform RESET of the CPU
4243 echo - echo args to console
4244 version - print monitor version
4245 help - print online help
4246 ? - alias for 'help'
4249 Monitor Commands - Detailed Description:
4250 ========================================
4254 For now: just type "help <command>".
4257 Environment Variables:
4258 ======================
4260 U-Boot supports user configuration using Environment Variables which
4261 can be made persistent by saving to Flash memory.
4263 Environment Variables are set using "setenv", printed using
4264 "printenv", and saved to Flash using "saveenv". Using "setenv"
4265 without a value can be used to delete a variable from the
4266 environment. As long as you don't save the environment you are
4267 working with an in-memory copy. In case the Flash area containing the
4268 environment is erased by accident, a default environment is provided.
4270 Some configuration options can be set using Environment Variables.
4272 List of environment variables (most likely not complete):
4274 baudrate - see CONFIG_BAUDRATE
4276 bootdelay - see CONFIG_BOOTDELAY
4278 bootcmd - see CONFIG_BOOTCOMMAND
4280 bootargs - Boot arguments when booting an RTOS image
4282 bootfile - Name of the image to load with TFTP
4284 bootm_low - Memory range available for image processing in the bootm
4285 command can be restricted. This variable is given as
4286 a hexadecimal number and defines lowest address allowed
4287 for use by the bootm command. See also "bootm_size"
4288 environment variable. Address defined by "bootm_low" is
4289 also the base of the initial memory mapping for the Linux
4290 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4293 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4294 This variable is given as a hexadecimal number and it
4295 defines the size of the memory region starting at base
4296 address bootm_low that is accessible by the Linux kernel
4297 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4298 as the default value if it is defined, and bootm_size is
4301 bootm_size - Memory range available for image processing in the bootm
4302 command can be restricted. This variable is given as
4303 a hexadecimal number and defines the size of the region
4304 allowed for use by the bootm command. See also "bootm_low"
4305 environment variable.
4307 updatefile - Location of the software update file on a TFTP server, used
4308 by the automatic software update feature. Please refer to
4309 documentation in doc/README.update for more details.
4311 autoload - if set to "no" (any string beginning with 'n'),
4312 "bootp" will just load perform a lookup of the
4313 configuration from the BOOTP server, but not try to
4314 load any image using TFTP
4316 autostart - if set to "yes", an image loaded using the "bootp",
4317 "rarpboot", "tftpboot" or "diskboot" commands will
4318 be automatically started (by internally calling
4321 If set to "no", a standalone image passed to the
4322 "bootm" command will be copied to the load address
4323 (and eventually uncompressed), but NOT be started.
4324 This can be used to load and uncompress arbitrary
4327 fdt_high - if set this restricts the maximum address that the
4328 flattened device tree will be copied into upon boot.
4329 For example, if you have a system with 1 GB memory
4330 at physical address 0x10000000, while Linux kernel
4331 only recognizes the first 704 MB as low memory, you
4332 may need to set fdt_high as 0x3C000000 to have the
4333 device tree blob be copied to the maximum address
4334 of the 704 MB low memory, so that Linux kernel can
4335 access it during the boot procedure.
4337 If this is set to the special value 0xFFFFFFFF then
4338 the fdt will not be copied at all on boot. For this
4339 to work it must reside in writable memory, have
4340 sufficient padding on the end of it for u-boot to
4341 add the information it needs into it, and the memory
4342 must be accessible by the kernel.
4344 fdtcontroladdr- if set this is the address of the control flattened
4345 device tree used by U-Boot when CONFIG_OF_CONTROL is
4348 i2cfast - (PPC405GP|PPC405EP only)
4349 if set to 'y' configures Linux I2C driver for fast
4350 mode (400kHZ). This environment variable is used in
4351 initialization code. So, for changes to be effective
4352 it must be saved and board must be reset.
4354 initrd_high - restrict positioning of initrd images:
4355 If this variable is not set, initrd images will be
4356 copied to the highest possible address in RAM; this
4357 is usually what you want since it allows for
4358 maximum initrd size. If for some reason you want to
4359 make sure that the initrd image is loaded below the
4360 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4361 variable to a value of "no" or "off" or "0".
4362 Alternatively, you can set it to a maximum upper
4363 address to use (U-Boot will still check that it
4364 does not overwrite the U-Boot stack and data).
4366 For instance, when you have a system with 16 MB
4367 RAM, and want to reserve 4 MB from use by Linux,
4368 you can do this by adding "mem=12M" to the value of
4369 the "bootargs" variable. However, now you must make
4370 sure that the initrd image is placed in the first
4371 12 MB as well - this can be done with
4373 setenv initrd_high 00c00000
4375 If you set initrd_high to 0xFFFFFFFF, this is an
4376 indication to U-Boot that all addresses are legal
4377 for the Linux kernel, including addresses in flash
4378 memory. In this case U-Boot will NOT COPY the
4379 ramdisk at all. This may be useful to reduce the
4380 boot time on your system, but requires that this
4381 feature is supported by your Linux kernel.
4383 ipaddr - IP address; needed for tftpboot command
4385 loadaddr - Default load address for commands like "bootp",
4386 "rarpboot", "tftpboot", "loadb" or "diskboot"
4388 loads_echo - see CONFIG_LOADS_ECHO
4390 serverip - TFTP server IP address; needed for tftpboot command
4392 bootretry - see CONFIG_BOOT_RETRY_TIME
4394 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4396 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4398 ethprime - controls which interface is used first.
4400 ethact - controls which interface is currently active.
4401 For example you can do the following
4403 => setenv ethact FEC
4404 => ping 192.168.0.1 # traffic sent on FEC
4405 => setenv ethact SCC
4406 => ping 10.0.0.1 # traffic sent on SCC
4408 ethrotate - When set to "no" U-Boot does not go through all
4409 available network interfaces.
4410 It just stays at the currently selected interface.
4412 netretry - When set to "no" each network operation will
4413 either succeed or fail without retrying.
4414 When set to "once" the network operation will
4415 fail when all the available network interfaces
4416 are tried once without success.
4417 Useful on scripts which control the retry operation
4420 npe_ucode - set load address for the NPE microcode
4422 tftpsrcport - If this is set, the value is used for TFTP's
4425 tftpdstport - If this is set, the value is used for TFTP's UDP
4426 destination port instead of the Well Know Port 69.
4428 tftpblocksize - Block size to use for TFTP transfers; if not set,
4429 we use the TFTP server's default block size
4431 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4432 seconds, minimum value is 1000 = 1 second). Defines
4433 when a packet is considered to be lost so it has to
4434 be retransmitted. The default is 5000 = 5 seconds.
4435 Lowering this value may make downloads succeed
4436 faster in networks with high packet loss rates or
4437 with unreliable TFTP servers.
4439 vlan - When set to a value < 4095 the traffic over
4440 Ethernet is encapsulated/received over 802.1q
4443 The following image location variables contain the location of images
4444 used in booting. The "Image" column gives the role of the image and is
4445 not an environment variable name. The other columns are environment
4446 variable names. "File Name" gives the name of the file on a TFTP
4447 server, "RAM Address" gives the location in RAM the image will be
4448 loaded to, and "Flash Location" gives the image's address in NOR
4449 flash or offset in NAND flash.
4451 *Note* - these variables don't have to be defined for all boards, some
4452 boards currenlty use other variables for these purposes, and some
4453 boards use these variables for other purposes.
4455 Image File Name RAM Address Flash Location
4456 ----- --------- ----------- --------------
4457 u-boot u-boot u-boot_addr_r u-boot_addr
4458 Linux kernel bootfile kernel_addr_r kernel_addr
4459 device tree blob fdtfile fdt_addr_r fdt_addr
4460 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4462 The following environment variables may be used and automatically
4463 updated by the network boot commands ("bootp" and "rarpboot"),
4464 depending the information provided by your boot server:
4466 bootfile - see above
4467 dnsip - IP address of your Domain Name Server
4468 dnsip2 - IP address of your secondary Domain Name Server
4469 gatewayip - IP address of the Gateway (Router) to use
4470 hostname - Target hostname
4472 netmask - Subnet Mask
4473 rootpath - Pathname of the root filesystem on the NFS server
4474 serverip - see above
4477 There are two special Environment Variables:
4479 serial# - contains hardware identification information such
4480 as type string and/or serial number
4481 ethaddr - Ethernet address
4483 These variables can be set only once (usually during manufacturing of
4484 the board). U-Boot refuses to delete or overwrite these variables
4485 once they have been set once.
4488 Further special Environment Variables:
4490 ver - Contains the U-Boot version string as printed
4491 with the "version" command. This variable is
4492 readonly (see CONFIG_VERSION_VARIABLE).
4495 Please note that changes to some configuration parameters may take
4496 only effect after the next boot (yes, that's just like Windoze :-).
4499 Callback functions for environment variables:
4500 ---------------------------------------------
4502 For some environment variables, the behavior of u-boot needs to change
4503 when their values are changed. This functionailty allows functions to
4504 be associated with arbitrary variables. On creation, overwrite, or
4505 deletion, the callback will provide the opportunity for some side
4506 effect to happen or for the change to be rejected.
4508 The callbacks are named and associated with a function using the
4509 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4511 These callbacks are associated with variables in one of two ways. The
4512 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4513 in the board configuration to a string that defines a list of
4514 associations. The list must be in the following format:
4516 entry = variable_name[:callback_name]
4519 If the callback name is not specified, then the callback is deleted.
4520 Spaces are also allowed anywhere in the list.
4522 Callbacks can also be associated by defining the ".callbacks" variable
4523 with the same list format above. Any association in ".callbacks" will
4524 override any association in the static list. You can define
4525 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4526 ".callbacks" envirnoment variable in the default or embedded environment.
4529 Command Line Parsing:
4530 =====================
4532 There are two different command line parsers available with U-Boot:
4533 the old "simple" one, and the much more powerful "hush" shell:
4535 Old, simple command line parser:
4536 --------------------------------
4538 - supports environment variables (through setenv / saveenv commands)
4539 - several commands on one line, separated by ';'
4540 - variable substitution using "... ${name} ..." syntax
4541 - special characters ('$', ';') can be escaped by prefixing with '\',
4543 setenv bootcmd bootm \${address}
4544 - You can also escape text by enclosing in single apostrophes, for example:
4545 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4550 - similar to Bourne shell, with control structures like
4551 if...then...else...fi, for...do...done; while...do...done,
4552 until...do...done, ...
4553 - supports environment ("global") variables (through setenv / saveenv
4554 commands) and local shell variables (through standard shell syntax
4555 "name=value"); only environment variables can be used with "run"
4561 (1) If a command line (or an environment variable executed by a "run"
4562 command) contains several commands separated by semicolon, and
4563 one of these commands fails, then the remaining commands will be
4566 (2) If you execute several variables with one call to run (i. e.
4567 calling run with a list of variables as arguments), any failing
4568 command will cause "run" to terminate, i. e. the remaining
4569 variables are not executed.
4571 Note for Redundant Ethernet Interfaces:
4572 =======================================
4574 Some boards come with redundant Ethernet interfaces; U-Boot supports
4575 such configurations and is capable of automatic selection of a
4576 "working" interface when needed. MAC assignment works as follows:
4578 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4579 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4580 "eth1addr" (=>eth1), "eth2addr", ...
4582 If the network interface stores some valid MAC address (for instance
4583 in SROM), this is used as default address if there is NO correspon-
4584 ding setting in the environment; if the corresponding environment
4585 variable is set, this overrides the settings in the card; that means:
4587 o If the SROM has a valid MAC address, and there is no address in the
4588 environment, the SROM's address is used.
4590 o If there is no valid address in the SROM, and a definition in the
4591 environment exists, then the value from the environment variable is
4594 o If both the SROM and the environment contain a MAC address, and
4595 both addresses are the same, this MAC address is used.
4597 o If both the SROM and the environment contain a MAC address, and the
4598 addresses differ, the value from the environment is used and a
4601 o If neither SROM nor the environment contain a MAC address, an error
4604 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4605 will be programmed into hardware as part of the initialization process. This
4606 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4607 The naming convention is as follows:
4608 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4613 U-Boot is capable of booting (and performing other auxiliary operations on)
4614 images in two formats:
4616 New uImage format (FIT)
4617 -----------------------
4619 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4620 to Flattened Device Tree). It allows the use of images with multiple
4621 components (several kernels, ramdisks, etc.), with contents protected by
4622 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4628 Old image format is based on binary files which can be basically anything,
4629 preceded by a special header; see the definitions in include/image.h for
4630 details; basically, the header defines the following image properties:
4632 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4633 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4634 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4635 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4637 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4638 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4639 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4640 * Compression Type (uncompressed, gzip, bzip2)
4646 The header is marked by a special Magic Number, and both the header
4647 and the data portions of the image are secured against corruption by
4654 Although U-Boot should support any OS or standalone application
4655 easily, the main focus has always been on Linux during the design of
4658 U-Boot includes many features that so far have been part of some
4659 special "boot loader" code within the Linux kernel. Also, any
4660 "initrd" images to be used are no longer part of one big Linux image;
4661 instead, kernel and "initrd" are separate images. This implementation
4662 serves several purposes:
4664 - the same features can be used for other OS or standalone
4665 applications (for instance: using compressed images to reduce the
4666 Flash memory footprint)
4668 - it becomes much easier to port new Linux kernel versions because
4669 lots of low-level, hardware dependent stuff are done by U-Boot
4671 - the same Linux kernel image can now be used with different "initrd"
4672 images; of course this also means that different kernel images can
4673 be run with the same "initrd". This makes testing easier (you don't
4674 have to build a new "zImage.initrd" Linux image when you just
4675 change a file in your "initrd"). Also, a field-upgrade of the
4676 software is easier now.
4682 Porting Linux to U-Boot based systems:
4683 ---------------------------------------
4685 U-Boot cannot save you from doing all the necessary modifications to
4686 configure the Linux device drivers for use with your target hardware
4687 (no, we don't intend to provide a full virtual machine interface to
4690 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4692 Just make sure your machine specific header file (for instance
4693 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4694 Information structure as we define in include/asm-<arch>/u-boot.h,
4695 and make sure that your definition of IMAP_ADDR uses the same value
4696 as your U-Boot configuration in CONFIG_SYS_IMMR.
4699 Configuring the Linux kernel:
4700 -----------------------------
4702 No specific requirements for U-Boot. Make sure you have some root
4703 device (initial ramdisk, NFS) for your target system.
4706 Building a Linux Image:
4707 -----------------------
4709 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4710 not used. If you use recent kernel source, a new build target
4711 "uImage" will exist which automatically builds an image usable by
4712 U-Boot. Most older kernels also have support for a "pImage" target,
4713 which was introduced for our predecessor project PPCBoot and uses a
4714 100% compatible format.
4723 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4724 encapsulate a compressed Linux kernel image with header information,
4725 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4727 * build a standard "vmlinux" kernel image (in ELF binary format):
4729 * convert the kernel into a raw binary image:
4731 ${CROSS_COMPILE}-objcopy -O binary \
4732 -R .note -R .comment \
4733 -S vmlinux linux.bin
4735 * compress the binary image:
4739 * package compressed binary image for U-Boot:
4741 mkimage -A ppc -O linux -T kernel -C gzip \
4742 -a 0 -e 0 -n "Linux Kernel Image" \
4743 -d linux.bin.gz uImage
4746 The "mkimage" tool can also be used to create ramdisk images for use
4747 with U-Boot, either separated from the Linux kernel image, or
4748 combined into one file. "mkimage" encapsulates the images with a 64
4749 byte header containing information about target architecture,
4750 operating system, image type, compression method, entry points, time
4751 stamp, CRC32 checksums, etc.
4753 "mkimage" can be called in two ways: to verify existing images and
4754 print the header information, or to build new images.
4756 In the first form (with "-l" option) mkimage lists the information
4757 contained in the header of an existing U-Boot image; this includes
4758 checksum verification:
4760 tools/mkimage -l image
4761 -l ==> list image header information
4763 The second form (with "-d" option) is used to build a U-Boot image
4764 from a "data file" which is used as image payload:
4766 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4767 -n name -d data_file image
4768 -A ==> set architecture to 'arch'
4769 -O ==> set operating system to 'os'
4770 -T ==> set image type to 'type'
4771 -C ==> set compression type 'comp'
4772 -a ==> set load address to 'addr' (hex)
4773 -e ==> set entry point to 'ep' (hex)
4774 -n ==> set image name to 'name'
4775 -d ==> use image data from 'datafile'
4777 Right now, all Linux kernels for PowerPC systems use the same load
4778 address (0x00000000), but the entry point address depends on the
4781 - 2.2.x kernels have the entry point at 0x0000000C,
4782 - 2.3.x and later kernels have the entry point at 0x00000000.
4784 So a typical call to build a U-Boot image would read:
4786 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4787 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4788 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4789 > examples/uImage.TQM850L
4790 Image Name: 2.4.4 kernel for TQM850L
4791 Created: Wed Jul 19 02:34:59 2000
4792 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4793 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4794 Load Address: 0x00000000
4795 Entry Point: 0x00000000
4797 To verify the contents of the image (or check for corruption):
4799 -> tools/mkimage -l examples/uImage.TQM850L
4800 Image Name: 2.4.4 kernel for TQM850L
4801 Created: Wed Jul 19 02:34:59 2000
4802 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4803 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4804 Load Address: 0x00000000
4805 Entry Point: 0x00000000
4807 NOTE: for embedded systems where boot time is critical you can trade
4808 speed for memory and install an UNCOMPRESSED image instead: this
4809 needs more space in Flash, but boots much faster since it does not
4810 need to be uncompressed:
4812 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4813 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4814 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4815 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4816 > examples/uImage.TQM850L-uncompressed
4817 Image Name: 2.4.4 kernel for TQM850L
4818 Created: Wed Jul 19 02:34:59 2000
4819 Image Type: PowerPC Linux Kernel Image (uncompressed)
4820 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4821 Load Address: 0x00000000
4822 Entry Point: 0x00000000
4825 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4826 when your kernel is intended to use an initial ramdisk:
4828 -> tools/mkimage -n 'Simple Ramdisk Image' \
4829 > -A ppc -O linux -T ramdisk -C gzip \
4830 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4831 Image Name: Simple Ramdisk Image
4832 Created: Wed Jan 12 14:01:50 2000
4833 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4834 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4835 Load Address: 0x00000000
4836 Entry Point: 0x00000000
4839 Installing a Linux Image:
4840 -------------------------
4842 To downloading a U-Boot image over the serial (console) interface,
4843 you must convert the image to S-Record format:
4845 objcopy -I binary -O srec examples/image examples/image.srec
4847 The 'objcopy' does not understand the information in the U-Boot
4848 image header, so the resulting S-Record file will be relative to
4849 address 0x00000000. To load it to a given address, you need to
4850 specify the target address as 'offset' parameter with the 'loads'
4853 Example: install the image to address 0x40100000 (which on the
4854 TQM8xxL is in the first Flash bank):
4856 => erase 40100000 401FFFFF
4862 ## Ready for S-Record download ...
4863 ~>examples/image.srec
4864 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4866 15989 15990 15991 15992
4867 [file transfer complete]
4869 ## Start Addr = 0x00000000
4872 You can check the success of the download using the 'iminfo' command;
4873 this includes a checksum verification so you can be sure no data
4874 corruption happened:
4878 ## Checking Image at 40100000 ...
4879 Image Name: 2.2.13 for initrd on TQM850L
4880 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4881 Data Size: 335725 Bytes = 327 kB = 0 MB
4882 Load Address: 00000000
4883 Entry Point: 0000000c
4884 Verifying Checksum ... OK
4890 The "bootm" command is used to boot an application that is stored in
4891 memory (RAM or Flash). In case of a Linux kernel image, the contents
4892 of the "bootargs" environment variable is passed to the kernel as
4893 parameters. You can check and modify this variable using the
4894 "printenv" and "setenv" commands:
4897 => printenv bootargs
4898 bootargs=root=/dev/ram
4900 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4902 => printenv bootargs
4903 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4906 ## Booting Linux kernel at 40020000 ...
4907 Image Name: 2.2.13 for NFS on TQM850L
4908 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4909 Data Size: 381681 Bytes = 372 kB = 0 MB
4910 Load Address: 00000000
4911 Entry Point: 0000000c
4912 Verifying Checksum ... OK
4913 Uncompressing Kernel Image ... OK
4914 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
4915 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4916 time_init: decrementer frequency = 187500000/60
4917 Calibrating delay loop... 49.77 BogoMIPS
4918 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4921 If you want to boot a Linux kernel with initial RAM disk, you pass
4922 the memory addresses of both the kernel and the initrd image (PPBCOOT
4923 format!) to the "bootm" command:
4925 => imi 40100000 40200000
4927 ## Checking Image at 40100000 ...
4928 Image Name: 2.2.13 for initrd on TQM850L
4929 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4930 Data Size: 335725 Bytes = 327 kB = 0 MB
4931 Load Address: 00000000
4932 Entry Point: 0000000c
4933 Verifying Checksum ... OK
4935 ## Checking Image at 40200000 ...
4936 Image Name: Simple Ramdisk Image
4937 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4938 Data Size: 566530 Bytes = 553 kB = 0 MB
4939 Load Address: 00000000
4940 Entry Point: 00000000
4941 Verifying Checksum ... OK
4943 => bootm 40100000 40200000
4944 ## Booting Linux kernel at 40100000 ...
4945 Image Name: 2.2.13 for initrd on TQM850L
4946 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4947 Data Size: 335725 Bytes = 327 kB = 0 MB
4948 Load Address: 00000000
4949 Entry Point: 0000000c
4950 Verifying Checksum ... OK
4951 Uncompressing Kernel Image ... OK
4952 ## Loading RAMDisk Image at 40200000 ...
4953 Image Name: Simple Ramdisk Image
4954 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4955 Data Size: 566530 Bytes = 553 kB = 0 MB
4956 Load Address: 00000000
4957 Entry Point: 00000000
4958 Verifying Checksum ... OK
4959 Loading Ramdisk ... OK
4960 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
4961 Boot arguments: root=/dev/ram
4962 time_init: decrementer frequency = 187500000/60
4963 Calibrating delay loop... 49.77 BogoMIPS
4965 RAMDISK: Compressed image found at block 0
4966 VFS: Mounted root (ext2 filesystem).
4970 Boot Linux and pass a flat device tree:
4973 First, U-Boot must be compiled with the appropriate defines. See the section
4974 titled "Linux Kernel Interface" above for a more in depth explanation. The
4975 following is an example of how to start a kernel and pass an updated
4981 oft=oftrees/mpc8540ads.dtb
4982 => tftp $oftaddr $oft
4983 Speed: 1000, full duplex
4985 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4986 Filename 'oftrees/mpc8540ads.dtb'.
4987 Load address: 0x300000
4990 Bytes transferred = 4106 (100a hex)
4991 => tftp $loadaddr $bootfile
4992 Speed: 1000, full duplex
4994 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4996 Load address: 0x200000
4997 Loading:############
4999 Bytes transferred = 1029407 (fb51f hex)
5004 => bootm $loadaddr - $oftaddr
5005 ## Booting image at 00200000 ...
5006 Image Name: Linux-2.6.17-dirty
5007 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5008 Data Size: 1029343 Bytes = 1005.2 kB
5009 Load Address: 00000000
5010 Entry Point: 00000000
5011 Verifying Checksum ... OK
5012 Uncompressing Kernel Image ... OK
5013 Booting using flat device tree at 0x300000
5014 Using MPC85xx ADS machine description
5015 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5019 More About U-Boot Image Types:
5020 ------------------------------
5022 U-Boot supports the following image types:
5024 "Standalone Programs" are directly runnable in the environment
5025 provided by U-Boot; it is expected that (if they behave
5026 well) you can continue to work in U-Boot after return from
5027 the Standalone Program.
5028 "OS Kernel Images" are usually images of some Embedded OS which
5029 will take over control completely. Usually these programs
5030 will install their own set of exception handlers, device
5031 drivers, set up the MMU, etc. - this means, that you cannot
5032 expect to re-enter U-Boot except by resetting the CPU.
5033 "RAMDisk Images" are more or less just data blocks, and their
5034 parameters (address, size) are passed to an OS kernel that is
5036 "Multi-File Images" contain several images, typically an OS
5037 (Linux) kernel image and one or more data images like
5038 RAMDisks. This construct is useful for instance when you want
5039 to boot over the network using BOOTP etc., where the boot
5040 server provides just a single image file, but you want to get
5041 for instance an OS kernel and a RAMDisk image.
5043 "Multi-File Images" start with a list of image sizes, each
5044 image size (in bytes) specified by an "uint32_t" in network
5045 byte order. This list is terminated by an "(uint32_t)0".
5046 Immediately after the terminating 0 follow the images, one by
5047 one, all aligned on "uint32_t" boundaries (size rounded up to
5048 a multiple of 4 bytes).
5050 "Firmware Images" are binary images containing firmware (like
5051 U-Boot or FPGA images) which usually will be programmed to
5054 "Script files" are command sequences that will be executed by
5055 U-Boot's command interpreter; this feature is especially
5056 useful when you configure U-Boot to use a real shell (hush)
5057 as command interpreter.
5059 Booting the Linux zImage:
5060 -------------------------
5062 On some platforms, it's possible to boot Linux zImage. This is done
5063 using the "bootz" command. The syntax of "bootz" command is the same
5064 as the syntax of "bootm" command.
5066 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5067 kernel with raw initrd images. The syntax is slightly different, the
5068 address of the initrd must be augmented by it's size, in the following
5069 format: "<initrd addres>:<initrd size>".
5075 One of the features of U-Boot is that you can dynamically load and
5076 run "standalone" applications, which can use some resources of
5077 U-Boot like console I/O functions or interrupt services.
5079 Two simple examples are included with the sources:
5084 'examples/hello_world.c' contains a small "Hello World" Demo
5085 application; it is automatically compiled when you build U-Boot.
5086 It's configured to run at address 0x00040004, so you can play with it
5090 ## Ready for S-Record download ...
5091 ~>examples/hello_world.srec
5092 1 2 3 4 5 6 7 8 9 10 11 ...
5093 [file transfer complete]
5095 ## Start Addr = 0x00040004
5097 => go 40004 Hello World! This is a test.
5098 ## Starting application at 0x00040004 ...
5109 Hit any key to exit ...
5111 ## Application terminated, rc = 0x0
5113 Another example, which demonstrates how to register a CPM interrupt
5114 handler with the U-Boot code, can be found in 'examples/timer.c'.
5115 Here, a CPM timer is set up to generate an interrupt every second.
5116 The interrupt service routine is trivial, just printing a '.'
5117 character, but this is just a demo program. The application can be
5118 controlled by the following keys:
5120 ? - print current values og the CPM Timer registers
5121 b - enable interrupts and start timer
5122 e - stop timer and disable interrupts
5123 q - quit application
5126 ## Ready for S-Record download ...
5127 ~>examples/timer.srec
5128 1 2 3 4 5 6 7 8 9 10 11 ...
5129 [file transfer complete]
5131 ## Start Addr = 0x00040004
5134 ## Starting application at 0x00040004 ...
5137 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5140 [q, b, e, ?] Set interval 1000000 us
5143 [q, b, e, ?] ........
5144 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5147 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5150 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5153 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5155 [q, b, e, ?] ...Stopping timer
5157 [q, b, e, ?] ## Application terminated, rc = 0x0
5163 Over time, many people have reported problems when trying to use the
5164 "minicom" terminal emulation program for serial download. I (wd)
5165 consider minicom to be broken, and recommend not to use it. Under
5166 Unix, I recommend to use C-Kermit for general purpose use (and
5167 especially for kermit binary protocol download ("loadb" command), and
5168 use "cu" for S-Record download ("loads" command). See
5169 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5170 for help with kermit.
5173 Nevertheless, if you absolutely want to use it try adding this
5174 configuration to your "File transfer protocols" section:
5176 Name Program Name U/D FullScr IO-Red. Multi
5177 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5178 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5184 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5185 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5187 Building requires a cross environment; it is known to work on
5188 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5189 need gmake since the Makefiles are not compatible with BSD make).
5190 Note that the cross-powerpc package does not install include files;
5191 attempting to build U-Boot will fail because <machine/ansi.h> is
5192 missing. This file has to be installed and patched manually:
5194 # cd /usr/pkg/cross/powerpc-netbsd/include
5196 # ln -s powerpc machine
5197 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5198 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5200 Native builds *don't* work due to incompatibilities between native
5201 and U-Boot include files.
5203 Booting assumes that (the first part of) the image booted is a
5204 stage-2 loader which in turn loads and then invokes the kernel
5205 proper. Loader sources will eventually appear in the NetBSD source
5206 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5207 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5210 Implementation Internals:
5211 =========================
5213 The following is not intended to be a complete description of every
5214 implementation detail. However, it should help to understand the
5215 inner workings of U-Boot and make it easier to port it to custom
5219 Initial Stack, Global Data:
5220 ---------------------------
5222 The implementation of U-Boot is complicated by the fact that U-Boot
5223 starts running out of ROM (flash memory), usually without access to
5224 system RAM (because the memory controller is not initialized yet).
5225 This means that we don't have writable Data or BSS segments, and BSS
5226 is not initialized as zero. To be able to get a C environment working
5227 at all, we have to allocate at least a minimal stack. Implementation
5228 options for this are defined and restricted by the CPU used: Some CPU
5229 models provide on-chip memory (like the IMMR area on MPC8xx and
5230 MPC826x processors), on others (parts of) the data cache can be
5231 locked as (mis-) used as memory, etc.
5233 Chris Hallinan posted a good summary of these issues to the
5234 U-Boot mailing list:
5236 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5237 From: "Chris Hallinan" <clh@net1plus.com>
5238 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5241 Correct me if I'm wrong, folks, but the way I understand it
5242 is this: Using DCACHE as initial RAM for Stack, etc, does not
5243 require any physical RAM backing up the cache. The cleverness
5244 is that the cache is being used as a temporary supply of
5245 necessary storage before the SDRAM controller is setup. It's
5246 beyond the scope of this list to explain the details, but you
5247 can see how this works by studying the cache architecture and
5248 operation in the architecture and processor-specific manuals.
5250 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5251 is another option for the system designer to use as an
5252 initial stack/RAM area prior to SDRAM being available. Either
5253 option should work for you. Using CS 4 should be fine if your
5254 board designers haven't used it for something that would
5255 cause you grief during the initial boot! It is frequently not
5258 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5259 with your processor/board/system design. The default value
5260 you will find in any recent u-boot distribution in
5261 walnut.h should work for you. I'd set it to a value larger
5262 than your SDRAM module. If you have a 64MB SDRAM module, set
5263 it above 400_0000. Just make sure your board has no resources
5264 that are supposed to respond to that address! That code in
5265 start.S has been around a while and should work as is when
5266 you get the config right.
5271 It is essential to remember this, since it has some impact on the C
5272 code for the initialization procedures:
5274 * Initialized global data (data segment) is read-only. Do not attempt
5277 * Do not use any uninitialized global data (or implicitely initialized
5278 as zero data - BSS segment) at all - this is undefined, initiali-
5279 zation is performed later (when relocating to RAM).
5281 * Stack space is very limited. Avoid big data buffers or things like
5284 Having only the stack as writable memory limits means we cannot use
5285 normal global data to share information beween the code. But it
5286 turned out that the implementation of U-Boot can be greatly
5287 simplified by making a global data structure (gd_t) available to all
5288 functions. We could pass a pointer to this data as argument to _all_
5289 functions, but this would bloat the code. Instead we use a feature of
5290 the GCC compiler (Global Register Variables) to share the data: we
5291 place a pointer (gd) to the global data into a register which we
5292 reserve for this purpose.
5294 When choosing a register for such a purpose we are restricted by the
5295 relevant (E)ABI specifications for the current architecture, and by
5296 GCC's implementation.
5298 For PowerPC, the following registers have specific use:
5300 R2: reserved for system use
5301 R3-R4: parameter passing and return values
5302 R5-R10: parameter passing
5303 R13: small data area pointer
5307 (U-Boot also uses R12 as internal GOT pointer. r12
5308 is a volatile register so r12 needs to be reset when
5309 going back and forth between asm and C)
5311 ==> U-Boot will use R2 to hold a pointer to the global data
5313 Note: on PPC, we could use a static initializer (since the
5314 address of the global data structure is known at compile time),
5315 but it turned out that reserving a register results in somewhat
5316 smaller code - although the code savings are not that big (on
5317 average for all boards 752 bytes for the whole U-Boot image,
5318 624 text + 127 data).
5320 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
5321 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
5323 ==> U-Boot will use P3 to hold a pointer to the global data
5325 On ARM, the following registers are used:
5327 R0: function argument word/integer result
5328 R1-R3: function argument word
5330 R10: stack limit (used only if stack checking if enabled)
5331 R11: argument (frame) pointer
5332 R12: temporary workspace
5335 R15: program counter
5337 ==> U-Boot will use R8 to hold a pointer to the global data
5339 On Nios II, the ABI is documented here:
5340 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5342 ==> U-Boot will use gp to hold a pointer to the global data
5344 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5345 to access small data sections, so gp is free.
5347 On NDS32, the following registers are used:
5349 R0-R1: argument/return
5351 R15: temporary register for assembler
5352 R16: trampoline register
5353 R28: frame pointer (FP)
5354 R29: global pointer (GP)
5355 R30: link register (LP)
5356 R31: stack pointer (SP)
5357 PC: program counter (PC)
5359 ==> U-Boot will use R10 to hold a pointer to the global data
5361 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5362 or current versions of GCC may "optimize" the code too much.
5367 U-Boot runs in system state and uses physical addresses, i.e. the
5368 MMU is not used either for address mapping nor for memory protection.
5370 The available memory is mapped to fixed addresses using the memory
5371 controller. In this process, a contiguous block is formed for each
5372 memory type (Flash, SDRAM, SRAM), even when it consists of several
5373 physical memory banks.
5375 U-Boot is installed in the first 128 kB of the first Flash bank (on
5376 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5377 booting and sizing and initializing DRAM, the code relocates itself
5378 to the upper end of DRAM. Immediately below the U-Boot code some
5379 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5380 configuration setting]. Below that, a structure with global Board
5381 Info data is placed, followed by the stack (growing downward).
5383 Additionally, some exception handler code is copied to the low 8 kB
5384 of DRAM (0x00000000 ... 0x00001FFF).
5386 So a typical memory configuration with 16 MB of DRAM could look like
5389 0x0000 0000 Exception Vector code
5392 0x0000 2000 Free for Application Use
5398 0x00FB FF20 Monitor Stack (Growing downward)
5399 0x00FB FFAC Board Info Data and permanent copy of global data
5400 0x00FC 0000 Malloc Arena
5403 0x00FE 0000 RAM Copy of Monitor Code
5404 ... eventually: LCD or video framebuffer
5405 ... eventually: pRAM (Protected RAM - unchanged by reset)
5406 0x00FF FFFF [End of RAM]
5409 System Initialization:
5410 ----------------------
5412 In the reset configuration, U-Boot starts at the reset entry point
5413 (on most PowerPC systems at address 0x00000100). Because of the reset
5414 configuration for CS0# this is a mirror of the onboard Flash memory.
5415 To be able to re-map memory U-Boot then jumps to its link address.
5416 To be able to implement the initialization code in C, a (small!)
5417 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5418 which provide such a feature like MPC8xx or MPC8260), or in a locked
5419 part of the data cache. After that, U-Boot initializes the CPU core,
5420 the caches and the SIU.
5422 Next, all (potentially) available memory banks are mapped using a
5423 preliminary mapping. For example, we put them on 512 MB boundaries
5424 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5425 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5426 programmed for SDRAM access. Using the temporary configuration, a
5427 simple memory test is run that determines the size of the SDRAM
5430 When there is more than one SDRAM bank, and the banks are of
5431 different size, the largest is mapped first. For equal size, the first
5432 bank (CS2#) is mapped first. The first mapping is always for address
5433 0x00000000, with any additional banks following immediately to create
5434 contiguous memory starting from 0.
5436 Then, the monitor installs itself at the upper end of the SDRAM area
5437 and allocates memory for use by malloc() and for the global Board
5438 Info data; also, the exception vector code is copied to the low RAM
5439 pages, and the final stack is set up.
5441 Only after this relocation will you have a "normal" C environment;
5442 until that you are restricted in several ways, mostly because you are
5443 running from ROM, and because the code will have to be relocated to a
5447 U-Boot Porting Guide:
5448 ----------------------
5450 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5454 int main(int argc, char *argv[])
5456 sighandler_t no_more_time;
5458 signal(SIGALRM, no_more_time);
5459 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5461 if (available_money > available_manpower) {
5462 Pay consultant to port U-Boot;
5466 Download latest U-Boot source;
5468 Subscribe to u-boot mailing list;
5471 email("Hi, I am new to U-Boot, how do I get started?");
5474 Read the README file in the top level directory;
5475 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5476 Read applicable doc/*.README;
5477 Read the source, Luke;
5478 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5481 if (available_money > toLocalCurrency ($2500))
5484 Add a lot of aggravation and time;
5486 if (a similar board exists) { /* hopefully... */
5487 cp -a board/<similar> board/<myboard>
5488 cp include/configs/<similar>.h include/configs/<myboard>.h
5490 Create your own board support subdirectory;
5491 Create your own board include/configs/<myboard>.h file;
5493 Edit new board/<myboard> files
5494 Edit new include/configs/<myboard>.h
5499 Add / modify source code;
5503 email("Hi, I am having problems...");
5505 Send patch file to the U-Boot email list;
5506 if (reasonable critiques)
5507 Incorporate improvements from email list code review;
5509 Defend code as written;
5515 void no_more_time (int sig)
5524 All contributions to U-Boot should conform to the Linux kernel
5525 coding style; see the file "Documentation/CodingStyle" and the script
5526 "scripts/Lindent" in your Linux kernel source directory.
5528 Source files originating from a different project (for example the
5529 MTD subsystem) are generally exempt from these guidelines and are not
5530 reformated to ease subsequent migration to newer versions of those
5533 Please note that U-Boot is implemented in C (and to some small parts in
5534 Assembler); no C++ is used, so please do not use C++ style comments (//)
5537 Please also stick to the following formatting rules:
5538 - remove any trailing white space
5539 - use TAB characters for indentation and vertical alignment, not spaces
5540 - make sure NOT to use DOS '\r\n' line feeds
5541 - do not add more than 2 consecutive empty lines to source files
5542 - do not add trailing empty lines to source files
5544 Submissions which do not conform to the standards may be returned
5545 with a request to reformat the changes.
5551 Since the number of patches for U-Boot is growing, we need to
5552 establish some rules. Submissions which do not conform to these rules
5553 may be rejected, even when they contain important and valuable stuff.
5555 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5557 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5558 see http://lists.denx.de/mailman/listinfo/u-boot
5560 When you send a patch, please include the following information with
5563 * For bug fixes: a description of the bug and how your patch fixes
5564 this bug. Please try to include a way of demonstrating that the
5565 patch actually fixes something.
5567 * For new features: a description of the feature and your
5570 * A CHANGELOG entry as plaintext (separate from the patch)
5572 * For major contributions, your entry to the CREDITS file
5574 * When you add support for a new board, don't forget to add this
5575 board to the MAINTAINERS file, too.
5577 * If your patch adds new configuration options, don't forget to
5578 document these in the README file.
5580 * The patch itself. If you are using git (which is *strongly*
5581 recommended) you can easily generate the patch using the
5582 "git format-patch". If you then use "git send-email" to send it to
5583 the U-Boot mailing list, you will avoid most of the common problems
5584 with some other mail clients.
5586 If you cannot use git, use "diff -purN OLD NEW". If your version of
5587 diff does not support these options, then get the latest version of
5590 The current directory when running this command shall be the parent
5591 directory of the U-Boot source tree (i. e. please make sure that
5592 your patch includes sufficient directory information for the
5595 We prefer patches as plain text. MIME attachments are discouraged,
5596 and compressed attachments must not be used.
5598 * If one logical set of modifications affects or creates several
5599 files, all these changes shall be submitted in a SINGLE patch file.
5601 * Changesets that contain different, unrelated modifications shall be
5602 submitted as SEPARATE patches, one patch per changeset.
5607 * Before sending the patch, run the MAKEALL script on your patched
5608 source tree and make sure that no errors or warnings are reported
5609 for any of the boards.
5611 * Keep your modifications to the necessary minimum: A patch
5612 containing several unrelated changes or arbitrary reformats will be
5613 returned with a request to re-formatting / split it.
5615 * If you modify existing code, make sure that your new code does not
5616 add to the memory footprint of the code ;-) Small is beautiful!
5617 When adding new features, these should compile conditionally only
5618 (using #ifdef), and the resulting code with the new feature
5619 disabled must not need more memory than the old code without your
5622 * Remember that there is a size limit of 100 kB per message on the
5623 u-boot mailing list. Bigger patches will be moderated. If they are
5624 reasonable and not too big, they will be acknowledged. But patches
5625 bigger than the size limit should be avoided.
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