2 # (C) Copyright 2000 - 2009
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
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 Starting with the release in October 2008, the names of the releases
130 were changed from numerical release numbers without deeper meaning
131 into a time stamp based numbering. Regular releases are identified by
132 names consisting of the calendar year and month of the release date.
133 Additional fields (if present) indicate release candidates or bug fix
134 releases in "stable" maintenance trees.
137 U-Boot v2009.11 - Release November 2009
138 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
139 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
145 /arch Architecture specific files
146 /arm Files generic to ARM architecture
147 /cpu CPU specific files
148 /arm720t Files specific to ARM 720 CPUs
149 /arm920t Files specific to ARM 920 CPUs
150 /at91rm9200 Files specific to Atmel AT91RM9200 CPU
151 /imx Files specific to Freescale MC9328 i.MX CPUs
152 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
153 /arm925t Files specific to ARM 925 CPUs
154 /arm926ejs Files specific to ARM 926 CPUs
155 /arm1136 Files specific to ARM 1136 CPUs
156 /ixp Files specific to Intel XScale IXP CPUs
157 /pxa Files specific to Intel XScale PXA CPUs
158 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
159 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
160 /lib Architecture specific library files
161 /avr32 Files generic to AVR32 architecture
162 /cpu CPU specific files
163 /lib Architecture specific library files
164 /blackfin Files generic to Analog Devices Blackfin architecture
165 /cpu CPU specific files
166 /lib Architecture specific library files
167 /i386 Files generic to i386 architecture
168 /cpu CPU specific files
169 /lib Architecture specific library files
170 /m68k Files generic to m68k architecture
171 /cpu CPU specific files
172 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
173 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
174 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
175 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
176 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
177 /lib Architecture specific library files
178 /microblaze Files generic to microblaze architecture
179 /cpu CPU specific files
180 /lib Architecture specific library files
181 /mips Files generic to MIPS architecture
182 /cpu CPU specific files
183 /lib Architecture specific library files
184 /nios2 Files generic to Altera NIOS2 architecture
185 /cpu CPU specific files
186 /lib Architecture specific library files
187 /powerpc Files generic to PowerPC architecture
188 /cpu CPU specific files
189 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
190 /mpc5xx Files specific to Freescale MPC5xx CPUs
191 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
192 /mpc8xx Files specific to Freescale MPC8xx CPUs
193 /mpc8220 Files specific to Freescale MPC8220 CPUs
194 /mpc824x Files specific to Freescale MPC824x CPUs
195 /mpc8260 Files specific to Freescale MPC8260 CPUs
196 /mpc85xx Files specific to Freescale MPC85xx CPUs
197 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
198 /lib Architecture specific library files
199 /sh Files generic to SH architecture
200 /cpu CPU specific files
201 /sh2 Files specific to sh2 CPUs
202 /sh3 Files specific to sh3 CPUs
203 /sh4 Files specific to sh4 CPUs
204 /lib Architecture specific library files
205 /sparc Files generic to SPARC architecture
206 /cpu CPU specific files
207 /leon2 Files specific to Gaisler LEON2 SPARC CPU
208 /leon3 Files specific to Gaisler LEON3 SPARC CPU
209 /lib Architecture specific library files
210 /api Machine/arch independent API for external apps
211 /board Board dependent files
212 /common Misc architecture independent functions
213 /disk Code for disk drive partition handling
214 /doc Documentation (don't expect too much)
215 /drivers Commonly used device drivers
216 /examples Example code for standalone applications, etc.
217 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
218 /include Header Files
219 /lib Files generic to all architectures
220 /libfdt Library files to support flattened device trees
221 /lzma Library files to support LZMA decompression
222 /lzo Library files to support LZO decompression
224 /post Power On Self Test
225 /rtc Real Time Clock drivers
226 /tools Tools to build S-Record or U-Boot images, etc.
228 Software Configuration:
229 =======================
231 Configuration is usually done using C preprocessor defines; the
232 rationale behind that is to avoid dead code whenever possible.
234 There are two classes of configuration variables:
236 * Configuration _OPTIONS_:
237 These are selectable by the user and have names beginning with
240 * Configuration _SETTINGS_:
241 These depend on the hardware etc. and should not be meddled with if
242 you don't know what you're doing; they have names beginning with
245 Later we will add a configuration tool - probably similar to or even
246 identical to what's used for the Linux kernel. Right now, we have to
247 do the configuration by hand, which means creating some symbolic
248 links and editing some configuration files. We use the TQM8xxL boards
252 Selection of Processor Architecture and Board Type:
253 ---------------------------------------------------
255 For all supported boards there are ready-to-use default
256 configurations available; just type "make <board_name>_config".
258 Example: For a TQM823L module type:
263 For the Cogent platform, you need to specify the CPU type as well;
264 e.g. "make cogent_mpc8xx_config". And also configure the cogent
265 directory according to the instructions in cogent/README.
268 Configuration Options:
269 ----------------------
271 Configuration depends on the combination of board and CPU type; all
272 such information is kept in a configuration file
273 "include/configs/<board_name>.h".
275 Example: For a TQM823L module, all configuration settings are in
276 "include/configs/TQM823L.h".
279 Many of the options are named exactly as the corresponding Linux
280 kernel configuration options. The intention is to make it easier to
281 build a config tool - later.
284 The following options need to be configured:
286 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
288 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
290 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
291 Define exactly one, e.g. CONFIG_ATSTK1002
293 - CPU Module Type: (if CONFIG_COGENT is defined)
294 Define exactly one of
296 --- FIXME --- not tested yet:
297 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
298 CONFIG_CMA287_23, CONFIG_CMA287_50
300 - Motherboard Type: (if CONFIG_COGENT is defined)
301 Define exactly one of
302 CONFIG_CMA101, CONFIG_CMA102
304 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
305 Define one or more of
308 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
309 Define one or more of
310 CONFIG_LCD_HEARTBEAT - update a character position on
311 the LCD display every second with
314 - Board flavour: (if CONFIG_MPC8260ADS is defined)
317 CONFIG_SYS_8260ADS - original MPC8260ADS
318 CONFIG_SYS_8266ADS - MPC8266ADS
319 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
320 CONFIG_SYS_8272ADS - MPC8272ADS
322 - Marvell Family Member
323 CONFIG_SYS_MVFS - define it if you want to enable
324 multiple fs option at one time
325 for marvell soc family
327 - MPC824X Family Member (if CONFIG_MPC824X is defined)
328 Define exactly one of
329 CONFIG_MPC8240, CONFIG_MPC8245
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
359 - Intel Monahans options:
360 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
362 Defines the Monahans run mode to oscillator
363 ratio. Valid values are 8, 16, 24, 31. The core
364 frequency is this value multiplied by 13 MHz.
366 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
368 Defines the Monahans turbo mode to oscillator
369 ratio. Valid values are 1 (default if undefined) and
370 2. The core frequency as calculated above is multiplied
373 - Linux Kernel Interface:
376 U-Boot stores all clock information in Hz
377 internally. For binary compatibility with older Linux
378 kernels (which expect the clocks passed in the
379 bd_info data to be in MHz) the environment variable
380 "clocks_in_mhz" can be defined so that U-Boot
381 converts clock data to MHZ before passing it to the
383 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
384 "clocks_in_mhz=1" is automatically included in the
387 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
389 When transferring memsize parameter to linux, some versions
390 expect it to be in bytes, others in MB.
391 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
395 New kernel versions are expecting firmware settings to be
396 passed using flattened device trees (based on open firmware
400 * New libfdt-based support
401 * Adds the "fdt" command
402 * The bootm command automatically updates the fdt
404 OF_CPU - The proper name of the cpus node (only required for
405 MPC512X and MPC5xxx based boards).
406 OF_SOC - The proper name of the soc node (only required for
407 MPC512X and MPC5xxx based boards).
408 OF_TBCLK - The timebase frequency.
409 OF_STDOUT_PATH - The path to the console device
411 boards with QUICC Engines require OF_QE to set UCC MAC
414 CONFIG_OF_BOARD_SETUP
416 Board code has addition modification that it wants to make
417 to the flat device tree before handing it off to the kernel
421 This define fills in the correct boot CPU in the boot
422 param header, the default value is zero if undefined.
426 U-Boot can detect if an IDE device is present or not.
427 If not, and this new config option is activated, U-Boot
428 removes the ATA node from the DTS before booting Linux,
429 so the Linux IDE driver does not probe the device and
430 crash. This is needed for buggy hardware (uc101) where
431 no pull down resistor is connected to the signal IDE5V_DD7.
433 - vxWorks boot parameters:
435 bootvx constructs a valid bootline using the following
436 environments variables: bootfile, ipaddr, serverip, hostname.
437 It loads the vxWorks image pointed bootfile.
439 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
440 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
441 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
442 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
444 CONFIG_SYS_VXWORKS_ADD_PARAMS
446 Add it at the end of the bootline. E.g "u=username pw=secret"
448 Note: If a "bootargs" environment is defined, it will overwride
449 the defaults discussed just above.
454 Define this if you want support for Amba PrimeCell PL010 UARTs.
458 Define this if you want support for Amba PrimeCell PL011 UARTs.
462 If you have Amba PrimeCell PL011 UARTs, set this variable to
463 the clock speed of the UARTs.
467 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
468 define this to a list of base addresses for each (supported)
469 port. See e.g. include/configs/versatile.h
473 Depending on board, define exactly one serial port
474 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
475 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
476 console by defining CONFIG_8xx_CONS_NONE
478 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
479 port routines must be defined elsewhere
480 (i.e. serial_init(), serial_getc(), ...)
483 Enables console device for a color framebuffer. Needs following
484 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
485 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
487 VIDEO_HW_RECTFILL graphic chip supports
490 VIDEO_HW_BITBLT graphic chip supports
491 bit-blit (cf. smiLynxEM)
492 VIDEO_VISIBLE_COLS visible pixel columns
494 VIDEO_VISIBLE_ROWS visible pixel rows
495 VIDEO_PIXEL_SIZE bytes per pixel
496 VIDEO_DATA_FORMAT graphic data format
497 (0-5, cf. cfb_console.c)
498 VIDEO_FB_ADRS framebuffer address
499 VIDEO_KBD_INIT_FCT keyboard int fct
500 (i.e. i8042_kbd_init())
501 VIDEO_TSTC_FCT test char fct
503 VIDEO_GETC_FCT get char fct
505 CONFIG_CONSOLE_CURSOR cursor drawing on/off
506 (requires blink timer
508 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
509 CONFIG_CONSOLE_TIME display time/date info in
511 (requires CONFIG_CMD_DATE)
512 CONFIG_VIDEO_LOGO display Linux logo in
514 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
515 linux_logo.h for logo.
516 Requires CONFIG_VIDEO_LOGO
517 CONFIG_CONSOLE_EXTRA_INFO
518 additional board info beside
521 When CONFIG_CFB_CONSOLE is defined, video console is
522 default i/o. Serial console can be forced with
523 environment 'console=serial'.
525 When CONFIG_SILENT_CONSOLE is defined, all console
526 messages (by U-Boot and Linux!) can be silenced with
527 the "silent" environment variable. See
528 doc/README.silent for more information.
531 CONFIG_BAUDRATE - in bps
532 Select one of the baudrates listed in
533 CONFIG_SYS_BAUDRATE_TABLE, see below.
534 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
536 - Console Rx buffer length
537 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
538 the maximum receive buffer length for the SMC.
539 This option is actual only for 82xx and 8xx possible.
540 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
541 must be defined, to setup the maximum idle timeout for
544 - Boot Delay: CONFIG_BOOTDELAY - in seconds
545 Delay before automatically booting the default image;
546 set to -1 to disable autoboot.
548 See doc/README.autoboot for these options that
549 work with CONFIG_BOOTDELAY. None are required.
550 CONFIG_BOOT_RETRY_TIME
551 CONFIG_BOOT_RETRY_MIN
552 CONFIG_AUTOBOOT_KEYED
553 CONFIG_AUTOBOOT_PROMPT
554 CONFIG_AUTOBOOT_DELAY_STR
555 CONFIG_AUTOBOOT_STOP_STR
556 CONFIG_AUTOBOOT_DELAY_STR2
557 CONFIG_AUTOBOOT_STOP_STR2
558 CONFIG_ZERO_BOOTDELAY_CHECK
559 CONFIG_RESET_TO_RETRY
563 Only needed when CONFIG_BOOTDELAY is enabled;
564 define a command string that is automatically executed
565 when no character is read on the console interface
566 within "Boot Delay" after reset.
569 This can be used to pass arguments to the bootm
570 command. The value of CONFIG_BOOTARGS goes into the
571 environment value "bootargs".
573 CONFIG_RAMBOOT and CONFIG_NFSBOOT
574 The value of these goes into the environment as
575 "ramboot" and "nfsboot" respectively, and can be used
576 as a convenience, when switching between booting from
582 When this option is #defined, the existence of the
583 environment variable "preboot" will be checked
584 immediately before starting the CONFIG_BOOTDELAY
585 countdown and/or running the auto-boot command resp.
586 entering interactive mode.
588 This feature is especially useful when "preboot" is
589 automatically generated or modified. For an example
590 see the LWMON board specific code: here "preboot" is
591 modified when the user holds down a certain
592 combination of keys on the (special) keyboard when
595 - Serial Download Echo Mode:
597 If defined to 1, all characters received during a
598 serial download (using the "loads" command) are
599 echoed back. This might be needed by some terminal
600 emulations (like "cu"), but may as well just take
601 time on others. This setting #define's the initial
602 value of the "loads_echo" environment variable.
604 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
606 Select one of the baudrates listed in
607 CONFIG_SYS_BAUDRATE_TABLE, see below.
610 Monitor commands can be included or excluded
611 from the build by using the #include files
612 "config_cmd_all.h" and #undef'ing unwanted
613 commands, or using "config_cmd_default.h"
614 and augmenting with additional #define's
617 The default command configuration includes all commands
618 except those marked below with a "*".
620 CONFIG_CMD_ASKENV * ask for env variable
621 CONFIG_CMD_BDI bdinfo
622 CONFIG_CMD_BEDBUG * Include BedBug Debugger
623 CONFIG_CMD_BMP * BMP support
624 CONFIG_CMD_BSP * Board specific commands
625 CONFIG_CMD_BOOTD bootd
626 CONFIG_CMD_CACHE * icache, dcache
627 CONFIG_CMD_CONSOLE coninfo
628 CONFIG_CMD_DATE * support for RTC, date/time...
629 CONFIG_CMD_DHCP * DHCP support
630 CONFIG_CMD_DIAG * Diagnostics
631 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
632 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
633 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
634 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
635 CONFIG_CMD_DTT * Digital Therm and Thermostat
636 CONFIG_CMD_ECHO echo arguments
637 CONFIG_CMD_EDITENV edit env variable
638 CONFIG_CMD_EEPROM * EEPROM read/write support
639 CONFIG_CMD_ELF * bootelf, bootvx
640 CONFIG_CMD_EXPORTENV * export the environment
641 CONFIG_CMD_SAVEENV saveenv
642 CONFIG_CMD_FDC * Floppy Disk Support
643 CONFIG_CMD_FAT * FAT partition support
644 CONFIG_CMD_FDOS * Dos diskette Support
645 CONFIG_CMD_FLASH flinfo, erase, protect
646 CONFIG_CMD_FPGA FPGA device initialization support
647 CONFIG_CMD_GO * the 'go' command (exec code)
648 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
649 CONFIG_CMD_I2C * I2C serial bus support
650 CONFIG_CMD_IDE * IDE harddisk support
651 CONFIG_CMD_IMI iminfo
652 CONFIG_CMD_IMLS List all found images
653 CONFIG_CMD_IMMAP * IMMR dump support
654 CONFIG_CMD_IMPORTENV * import an environment
655 CONFIG_CMD_IRQ * irqinfo
656 CONFIG_CMD_ITEST Integer/string test of 2 values
657 CONFIG_CMD_JFFS2 * JFFS2 Support
658 CONFIG_CMD_KGDB * kgdb
659 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
660 CONFIG_CMD_LOADB loadb
661 CONFIG_CMD_LOADS loads
662 CONFIG_CMD_MD5SUM print md5 message digest
663 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
664 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
666 CONFIG_CMD_MISC Misc functions like sleep etc
667 CONFIG_CMD_MMC * MMC memory mapped support
668 CONFIG_CMD_MII * MII utility commands
669 CONFIG_CMD_MTDPARTS * MTD partition support
670 CONFIG_CMD_NAND * NAND support
671 CONFIG_CMD_NET bootp, tftpboot, rarpboot
672 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
673 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
674 CONFIG_CMD_PCI * pciinfo
675 CONFIG_CMD_PCMCIA * PCMCIA support
676 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
678 CONFIG_CMD_PORTIO * Port I/O
679 CONFIG_CMD_REGINFO * Register dump
680 CONFIG_CMD_RUN run command in env variable
681 CONFIG_CMD_SAVES * save S record dump
682 CONFIG_CMD_SCSI * SCSI Support
683 CONFIG_CMD_SDRAM * print SDRAM configuration information
684 (requires CONFIG_CMD_I2C)
685 CONFIG_CMD_SETGETDCR Support for DCR Register access
687 CONFIG_CMD_SHA1SUM print sha1 memory digest
688 (requires CONFIG_CMD_MEMORY)
689 CONFIG_CMD_SOURCE "source" command Support
690 CONFIG_CMD_SPI * SPI serial bus support
691 CONFIG_CMD_USB * USB support
692 CONFIG_CMD_VFD * VFD support (TRAB)
693 CONFIG_CMD_CDP * Cisco Discover Protocol support
694 CONFIG_CMD_FSL * Microblaze FSL support
697 EXAMPLE: If you want all functions except of network
698 support you can write:
700 #include "config_cmd_all.h"
701 #undef CONFIG_CMD_NET
704 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
706 Note: Don't enable the "icache" and "dcache" commands
707 (configuration option CONFIG_CMD_CACHE) unless you know
708 what you (and your U-Boot users) are doing. Data
709 cache cannot be enabled on systems like the 8xx or
710 8260 (where accesses to the IMMR region must be
711 uncached), and it cannot be disabled on all other
712 systems where we (mis-) use the data cache to hold an
713 initial stack and some data.
716 XXX - this list needs to get updated!
720 If this variable is defined, it enables watchdog
721 support. There must be support in the platform specific
722 code for a watchdog. For the 8xx and 8260 CPUs, the
723 SIU Watchdog feature is enabled in the SYPCR
727 CONFIG_VERSION_VARIABLE
728 If this variable is defined, an environment variable
729 named "ver" is created by U-Boot showing the U-Boot
730 version as printed by the "version" command.
731 This variable is readonly.
735 When CONFIG_CMD_DATE is selected, the type of the RTC
736 has to be selected, too. Define exactly one of the
739 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
740 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
741 CONFIG_RTC_MC13783 - use MC13783 RTC
742 CONFIG_RTC_MC146818 - use MC146818 RTC
743 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
744 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
745 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
746 CONFIG_RTC_DS164x - use Dallas DS164x RTC
747 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
748 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
749 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
751 Note that if the RTC uses I2C, then the I2C interface
752 must also be configured. See I2C Support, below.
755 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
756 CONFIG_PCA953X_INFO - enable pca953x info command
758 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
759 chip-ngpio pairs that tell the PCA953X driver the number of
760 pins supported by a particular chip.
762 Note that if the GPIO device uses I2C, then the I2C interface
763 must also be configured. See I2C Support, below.
767 When CONFIG_TIMESTAMP is selected, the timestamp
768 (date and time) of an image is printed by image
769 commands like bootm or iminfo. This option is
770 automatically enabled when you select CONFIG_CMD_DATE .
773 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
774 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
776 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
777 CONFIG_CMD_SCSI) you must configure support for at
778 least one partition type as well.
781 CONFIG_IDE_RESET_ROUTINE - this is defined in several
782 board configurations files but used nowhere!
784 CONFIG_IDE_RESET - is this is defined, IDE Reset will
785 be performed by calling the function
786 ide_set_reset(int reset)
787 which has to be defined in a board specific file
792 Set this to enable ATAPI support.
797 Set this to enable support for disks larger than 137GB
798 Also look at CONFIG_SYS_64BIT_LBA.
799 Whithout these , LBA48 support uses 32bit variables and will 'only'
800 support disks up to 2.1TB.
802 CONFIG_SYS_64BIT_LBA:
803 When enabled, makes the IDE subsystem use 64bit sector addresses.
807 At the moment only there is only support for the
808 SYM53C8XX SCSI controller; define
809 CONFIG_SCSI_SYM53C8XX to enable it.
811 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
812 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
813 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
814 maximum numbers of LUNs, SCSI ID's and target
816 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
818 - NETWORK Support (PCI):
820 Support for Intel 8254x gigabit chips.
822 CONFIG_E1000_FALLBACK_MAC
823 default MAC for empty EEPROM after production.
826 Support for Intel 82557/82559/82559ER chips.
827 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
828 write routine for first time initialisation.
831 Support for Digital 2114x chips.
832 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
833 modem chip initialisation (KS8761/QS6611).
836 Support for National dp83815 chips.
839 Support for National dp8382[01] gigabit chips.
841 - NETWORK Support (other):
843 CONFIG_DRIVER_AT91EMAC
844 Support for AT91RM9200 EMAC.
847 Define this to use reduced MII inteface
849 CONFIG_DRIVER_AT91EMAC_QUIET
850 If this defined, the driver is quiet.
851 The driver doen't show link status messages.
853 CONFIG_DRIVER_LAN91C96
854 Support for SMSC's LAN91C96 chips.
857 Define this to hold the physical address
858 of the LAN91C96's I/O space
860 CONFIG_LAN91C96_USE_32_BIT
861 Define this to enable 32 bit addressing
863 CONFIG_DRIVER_SMC91111
864 Support for SMSC's LAN91C111 chip
867 Define this to hold the physical address
868 of the device (I/O space)
870 CONFIG_SMC_USE_32_BIT
871 Define this if data bus is 32 bits
873 CONFIG_SMC_USE_IOFUNCS
874 Define this to use i/o functions instead of macros
875 (some hardware wont work with macros)
878 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
880 CONFIG_FTGMAC100_EGIGA
881 Define this to use GE link update with gigabit PHY.
882 Define this if FTGMAC100 is connected to gigabit PHY.
883 If your system has 10/100 PHY only, it might not occur
884 wrong behavior. Because PHY usually return timeout or
885 useless data when polling gigabit status and gigabit
886 control registers. This behavior won't affect the
887 correctnessof 10/100 link speed update.
890 Support for SMSC's LAN911x and LAN921x chips
893 Define this to hold the physical address
894 of the device (I/O space)
896 CONFIG_SMC911X_32_BIT
897 Define this if data bus is 32 bits
899 CONFIG_SMC911X_16_BIT
900 Define this if data bus is 16 bits. If your processor
901 automatically converts one 32 bit word to two 16 bit
902 words you may also try CONFIG_SMC911X_32_BIT.
905 Support for Renesas on-chip Ethernet controller
907 CONFIG_SH_ETHER_USE_PORT
908 Define the number of ports to be used
910 CONFIG_SH_ETHER_PHY_ADDR
911 Define the ETH PHY's address
913 CONFIG_SH_ETHER_CACHE_WRITEBACK
914 If this option is set, the driver enables cache flush.
917 At the moment only the UHCI host controller is
918 supported (PIP405, MIP405, MPC5200); define
919 CONFIG_USB_UHCI to enable it.
920 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
921 and define CONFIG_USB_STORAGE to enable the USB
924 Supported are USB Keyboards and USB Floppy drives
926 MPC5200 USB requires additional defines:
928 for 528 MHz Clock: 0x0001bbbb
932 for differential drivers: 0x00001000
933 for single ended drivers: 0x00005000
934 for differential drivers on PSC3: 0x00000100
935 for single ended drivers on PSC3: 0x00004100
936 CONFIG_SYS_USB_EVENT_POLL
937 May be defined to allow interrupt polling
938 instead of using asynchronous interrupts
941 Define the below if you wish to use the USB console.
942 Once firmware is rebuilt from a serial console issue the
943 command "setenv stdin usbtty; setenv stdout usbtty" and
944 attach your USB cable. The Unix command "dmesg" should print
945 it has found a new device. The environment variable usbtty
946 can be set to gserial or cdc_acm to enable your device to
947 appear to a USB host as a Linux gserial device or a
948 Common Device Class Abstract Control Model serial device.
949 If you select usbtty = gserial you should be able to enumerate
951 # modprobe usbserial vendor=0xVendorID product=0xProductID
952 else if using cdc_acm, simply setting the environment
953 variable usbtty to be cdc_acm should suffice. The following
954 might be defined in YourBoardName.h
957 Define this to build a UDC device
960 Define this to have a tty type of device available to
961 talk to the UDC device
963 CONFIG_SYS_CONSOLE_IS_IN_ENV
964 Define this if you want stdin, stdout &/or stderr to
968 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
969 Derive USB clock from external clock "blah"
970 - CONFIG_SYS_USB_EXTC_CLK 0x02
972 CONFIG_SYS_USB_BRG_CLK 0xBLAH
973 Derive USB clock from brgclk
974 - CONFIG_SYS_USB_BRG_CLK 0x04
976 If you have a USB-IF assigned VendorID then you may wish to
977 define your own vendor specific values either in BoardName.h
978 or directly in usbd_vendor_info.h. If you don't define
979 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
980 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
981 should pretend to be a Linux device to it's target host.
983 CONFIG_USBD_MANUFACTURER
984 Define this string as the name of your company for
985 - CONFIG_USBD_MANUFACTURER "my company"
987 CONFIG_USBD_PRODUCT_NAME
988 Define this string as the name of your product
989 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
992 Define this as your assigned Vendor ID from the USB
993 Implementors Forum. This *must* be a genuine Vendor ID
994 to avoid polluting the USB namespace.
995 - CONFIG_USBD_VENDORID 0xFFFF
997 CONFIG_USBD_PRODUCTID
998 Define this as the unique Product ID
1000 - CONFIG_USBD_PRODUCTID 0xFFFF
1004 The MMC controller on the Intel PXA is supported. To
1005 enable this define CONFIG_MMC. The MMC can be
1006 accessed from the boot prompt by mapping the device
1007 to physical memory similar to flash. Command line is
1008 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1009 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1011 - Journaling Flash filesystem support:
1012 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1013 CONFIG_JFFS2_NAND_DEV
1014 Define these for a default partition on a NAND device
1016 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1017 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1018 Define these for a default partition on a NOR device
1020 CONFIG_SYS_JFFS_CUSTOM_PART
1021 Define this to create an own partition. You have to provide a
1022 function struct part_info* jffs2_part_info(int part_num)
1024 If you define only one JFFS2 partition you may also want to
1025 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1026 to disable the command chpart. This is the default when you
1027 have not defined a custom partition
1032 Define this to enable standard (PC-Style) keyboard
1036 Standard PC keyboard driver with US (is default) and
1037 GERMAN key layout (switch via environment 'keymap=de') support.
1038 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1039 for cfb_console. Supports cursor blinking.
1044 Define this to enable video support (for output to
1047 CONFIG_VIDEO_CT69000
1049 Enable Chips & Technologies 69000 Video chip
1051 CONFIG_VIDEO_SMI_LYNXEM
1052 Enable Silicon Motion SMI 712/710/810 Video chip. The
1053 video output is selected via environment 'videoout'
1054 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1057 For the CT69000 and SMI_LYNXEM drivers, videomode is
1058 selected via environment 'videomode'. Two different ways
1060 - "videomode=num" 'num' is a standard LiLo mode numbers.
1061 Following standard modes are supported (* is default):
1063 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1064 -------------+---------------------------------------------
1065 8 bits | 0x301* 0x303 0x305 0x161 0x307
1066 15 bits | 0x310 0x313 0x316 0x162 0x319
1067 16 bits | 0x311 0x314 0x317 0x163 0x31A
1068 24 bits | 0x312 0x315 0x318 ? 0x31B
1069 -------------+---------------------------------------------
1070 (i.e. setenv videomode 317; saveenv; reset;)
1072 - "videomode=bootargs" all the video parameters are parsed
1073 from the bootargs. (See drivers/video/videomodes.c)
1076 CONFIG_VIDEO_SED13806
1077 Enable Epson SED13806 driver. This driver supports 8bpp
1078 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1079 or CONFIG_VIDEO_SED13806_16BPP
1082 Enable the Freescale DIU video driver. Reference boards for
1083 SOCs that have a DIU should define this macro to enable DIU
1084 support, and should also define these other macros:
1090 CONFIG_VIDEO_SW_CURSOR
1091 CONFIG_VGA_AS_SINGLE_DEVICE
1093 CONFIG_VIDEO_BMP_LOGO
1095 The DIU driver will look for the 'monitor' environment variable,
1096 and if defined, enable the DIU as a console during boot. This
1097 variable should be set to one of these values:
1099 '0' Output video to the DVI connector
1100 '1' Output video to the LVDS connector
1101 '2' Output video to the Dual-Link LVDS connector
1106 Define this to enable a custom keyboard support.
1107 This simply calls drv_keyboard_init() which must be
1108 defined in your board-specific files.
1109 The only board using this so far is RBC823.
1111 - LCD Support: CONFIG_LCD
1113 Define this to enable LCD support (for output to LCD
1114 display); also select one of the supported displays
1115 by defining one of these:
1119 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1121 CONFIG_NEC_NL6448AC33:
1123 NEC NL6448AC33-18. Active, color, single scan.
1125 CONFIG_NEC_NL6448BC20
1127 NEC NL6448BC20-08. 6.5", 640x480.
1128 Active, color, single scan.
1130 CONFIG_NEC_NL6448BC33_54
1132 NEC NL6448BC33-54. 10.4", 640x480.
1133 Active, color, single scan.
1137 Sharp 320x240. Active, color, single scan.
1138 It isn't 16x9, and I am not sure what it is.
1140 CONFIG_SHARP_LQ64D341
1142 Sharp LQ64D341 display, 640x480.
1143 Active, color, single scan.
1147 HLD1045 display, 640x480.
1148 Active, color, single scan.
1152 Optrex CBL50840-2 NF-FW 99 22 M5
1154 Hitachi LMG6912RPFC-00T
1158 320x240. Black & white.
1160 Normally display is black on white background; define
1161 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1163 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1165 If this option is set, the environment is checked for
1166 a variable "splashimage". If found, the usual display
1167 of logo, copyright and system information on the LCD
1168 is suppressed and the BMP image at the address
1169 specified in "splashimage" is loaded instead. The
1170 console is redirected to the "nulldev", too. This
1171 allows for a "silent" boot where a splash screen is
1172 loaded very quickly after power-on.
1174 CONFIG_SPLASH_SCREEN_ALIGN
1176 If this option is set the splash image can be freely positioned
1177 on the screen. Environment variable "splashpos" specifies the
1178 position as "x,y". If a positive number is given it is used as
1179 number of pixel from left/top. If a negative number is given it
1180 is used as number of pixel from right/bottom. You can also
1181 specify 'm' for centering the image.
1184 setenv splashpos m,m
1185 => image at center of screen
1187 setenv splashpos 30,20
1188 => image at x = 30 and y = 20
1190 setenv splashpos -10,m
1191 => vertically centered image
1192 at x = dspWidth - bmpWidth - 9
1194 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1196 If this option is set, additionally to standard BMP
1197 images, gzipped BMP images can be displayed via the
1198 splashscreen support or the bmp command.
1200 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1202 If this option is set, 8-bit RLE compressed BMP images
1203 can be displayed via the splashscreen support or the
1206 - Compression support:
1209 If this option is set, support for bzip2 compressed
1210 images is included. If not, only uncompressed and gzip
1211 compressed images are supported.
1213 NOTE: the bzip2 algorithm requires a lot of RAM, so
1214 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1219 If this option is set, support for lzma compressed
1222 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1223 requires an amount of dynamic memory that is given by the
1226 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1228 Where lc and lp stand for, respectively, Literal context bits
1229 and Literal pos bits.
1231 This value is upper-bounded by 14MB in the worst case. Anyway,
1232 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1233 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1234 a very small buffer.
1236 Use the lzmainfo tool to determinate the lc and lp values and
1237 then calculate the amount of needed dynamic memory (ensuring
1238 the appropriate CONFIG_SYS_MALLOC_LEN value).
1243 The address of PHY on MII bus.
1245 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1247 The clock frequency of the MII bus
1251 If this option is set, support for speed/duplex
1252 detection of gigabit PHY is included.
1254 CONFIG_PHY_RESET_DELAY
1256 Some PHY like Intel LXT971A need extra delay after
1257 reset before any MII register access is possible.
1258 For such PHY, set this option to the usec delay
1259 required. (minimum 300usec for LXT971A)
1261 CONFIG_PHY_CMD_DELAY (ppc4xx)
1263 Some PHY like Intel LXT971A need extra delay after
1264 command issued before MII status register can be read
1274 Define a default value for Ethernet address to use
1275 for the respective Ethernet interface, in case this
1276 is not determined automatically.
1281 Define a default value for the IP address to use for
1282 the default Ethernet interface, in case this is not
1283 determined through e.g. bootp.
1285 - Server IP address:
1288 Defines a default value for the IP address of a TFTP
1289 server to contact when using the "tftboot" command.
1291 CONFIG_KEEP_SERVERADDR
1293 Keeps the server's MAC address, in the env 'serveraddr'
1294 for passing to bootargs (like Linux's netconsole option)
1296 - Multicast TFTP Mode:
1299 Defines whether you want to support multicast TFTP as per
1300 rfc-2090; for example to work with atftp. Lets lots of targets
1301 tftp down the same boot image concurrently. Note: the Ethernet
1302 driver in use must provide a function: mcast() to join/leave a
1305 CONFIG_BOOTP_RANDOM_DELAY
1306 - BOOTP Recovery Mode:
1307 CONFIG_BOOTP_RANDOM_DELAY
1309 If you have many targets in a network that try to
1310 boot using BOOTP, you may want to avoid that all
1311 systems send out BOOTP requests at precisely the same
1312 moment (which would happen for instance at recovery
1313 from a power failure, when all systems will try to
1314 boot, thus flooding the BOOTP server. Defining
1315 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1316 inserted before sending out BOOTP requests. The
1317 following delays are inserted then:
1319 1st BOOTP request: delay 0 ... 1 sec
1320 2nd BOOTP request: delay 0 ... 2 sec
1321 3rd BOOTP request: delay 0 ... 4 sec
1323 BOOTP requests: delay 0 ... 8 sec
1325 - DHCP Advanced Options:
1326 You can fine tune the DHCP functionality by defining
1327 CONFIG_BOOTP_* symbols:
1329 CONFIG_BOOTP_SUBNETMASK
1330 CONFIG_BOOTP_GATEWAY
1331 CONFIG_BOOTP_HOSTNAME
1332 CONFIG_BOOTP_NISDOMAIN
1333 CONFIG_BOOTP_BOOTPATH
1334 CONFIG_BOOTP_BOOTFILESIZE
1337 CONFIG_BOOTP_SEND_HOSTNAME
1338 CONFIG_BOOTP_NTPSERVER
1339 CONFIG_BOOTP_TIMEOFFSET
1340 CONFIG_BOOTP_VENDOREX
1342 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1343 environment variable, not the BOOTP server.
1345 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1346 serverip from a DHCP server, it is possible that more
1347 than one DNS serverip is offered to the client.
1348 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1349 serverip will be stored in the additional environment
1350 variable "dnsip2". The first DNS serverip is always
1351 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1354 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1355 to do a dynamic update of a DNS server. To do this, they
1356 need the hostname of the DHCP requester.
1357 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1358 of the "hostname" environment variable is passed as
1359 option 12 to the DHCP server.
1361 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1363 A 32bit value in microseconds for a delay between
1364 receiving a "DHCP Offer" and sending the "DHCP Request".
1365 This fixes a problem with certain DHCP servers that don't
1366 respond 100% of the time to a "DHCP request". E.g. On an
1367 AT91RM9200 processor running at 180MHz, this delay needed
1368 to be *at least* 15,000 usec before a Windows Server 2003
1369 DHCP server would reply 100% of the time. I recommend at
1370 least 50,000 usec to be safe. The alternative is to hope
1371 that one of the retries will be successful but note that
1372 the DHCP timeout and retry process takes a longer than
1376 CONFIG_CDP_DEVICE_ID
1378 The device id used in CDP trigger frames.
1380 CONFIG_CDP_DEVICE_ID_PREFIX
1382 A two character string which is prefixed to the MAC address
1387 A printf format string which contains the ascii name of
1388 the port. Normally is set to "eth%d" which sets
1389 eth0 for the first Ethernet, eth1 for the second etc.
1391 CONFIG_CDP_CAPABILITIES
1393 A 32bit integer which indicates the device capabilities;
1394 0x00000010 for a normal host which does not forwards.
1398 An ascii string containing the version of the software.
1402 An ascii string containing the name of the platform.
1406 A 32bit integer sent on the trigger.
1408 CONFIG_CDP_POWER_CONSUMPTION
1410 A 16bit integer containing the power consumption of the
1411 device in .1 of milliwatts.
1413 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1415 A byte containing the id of the VLAN.
1417 - Status LED: CONFIG_STATUS_LED
1419 Several configurations allow to display the current
1420 status using a LED. For instance, the LED will blink
1421 fast while running U-Boot code, stop blinking as
1422 soon as a reply to a BOOTP request was received, and
1423 start blinking slow once the Linux kernel is running
1424 (supported by a status LED driver in the Linux
1425 kernel). Defining CONFIG_STATUS_LED enables this
1428 - CAN Support: CONFIG_CAN_DRIVER
1430 Defining CONFIG_CAN_DRIVER enables CAN driver support
1431 on those systems that support this (optional)
1432 feature, like the TQM8xxL modules.
1434 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1436 These enable I2C serial bus commands. Defining either of
1437 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1438 include the appropriate I2C driver for the selected CPU.
1440 This will allow you to use i2c commands at the u-boot
1441 command line (as long as you set CONFIG_CMD_I2C in
1442 CONFIG_COMMANDS) and communicate with i2c based realtime
1443 clock chips. See common/cmd_i2c.c for a description of the
1444 command line interface.
1446 CONFIG_HARD_I2C selects a hardware I2C controller.
1448 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1449 bit-banging) driver instead of CPM or similar hardware
1452 There are several other quantities that must also be
1453 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1455 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1456 to be the frequency (in Hz) at which you wish your i2c bus
1457 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1458 the CPU's i2c node address).
1460 Now, the u-boot i2c code for the mpc8xx
1461 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1462 and so its address should therefore be cleared to 0 (See,
1463 eg, MPC823e User's Manual p.16-473). So, set
1464 CONFIG_SYS_I2C_SLAVE to 0.
1466 CONFIG_SYS_I2C_INIT_MPC5XXX
1468 When a board is reset during an i2c bus transfer
1469 chips might think that the current transfer is still
1470 in progress. Reset the slave devices by sending start
1471 commands until the slave device responds.
1473 That's all that's required for CONFIG_HARD_I2C.
1475 If you use the software i2c interface (CONFIG_SOFT_I2C)
1476 then the following macros need to be defined (examples are
1477 from include/configs/lwmon.h):
1481 (Optional). Any commands necessary to enable the I2C
1482 controller or configure ports.
1484 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1488 (Only for MPC8260 CPU). The I/O port to use (the code
1489 assumes both bits are on the same port). Valid values
1490 are 0..3 for ports A..D.
1494 The code necessary to make the I2C data line active
1495 (driven). If the data line is open collector, this
1498 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1502 The code necessary to make the I2C data line tri-stated
1503 (inactive). If the data line is open collector, this
1506 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1510 Code that returns TRUE if the I2C data line is high,
1513 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1517 If <bit> is TRUE, sets the I2C data line high. If it
1518 is FALSE, it clears it (low).
1520 eg: #define I2C_SDA(bit) \
1521 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1522 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1526 If <bit> is TRUE, sets the I2C clock line high. If it
1527 is FALSE, it clears it (low).
1529 eg: #define I2C_SCL(bit) \
1530 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1531 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1535 This delay is invoked four times per clock cycle so this
1536 controls the rate of data transfer. The data rate thus
1537 is 1 / (I2C_DELAY * 4). Often defined to be something
1540 #define I2C_DELAY udelay(2)
1542 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1544 If your arch supports the generic GPIO framework (asm/gpio.h),
1545 then you may alternatively define the two GPIOs that are to be
1546 used as SCL / SDA. Any of the previous I2C_xxx macros will
1547 have GPIO-based defaults assigned to them as appropriate.
1549 You should define these to the GPIO value as given directly to
1550 the generic GPIO functions.
1552 CONFIG_SYS_I2C_INIT_BOARD
1554 When a board is reset during an i2c bus transfer
1555 chips might think that the current transfer is still
1556 in progress. On some boards it is possible to access
1557 the i2c SCLK line directly, either by using the
1558 processor pin as a GPIO or by having a second pin
1559 connected to the bus. If this option is defined a
1560 custom i2c_init_board() routine in boards/xxx/board.c
1561 is run early in the boot sequence.
1563 CONFIG_SYS_I2C_BOARD_LATE_INIT
1565 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1566 defined a custom i2c_board_late_init() routine in
1567 boards/xxx/board.c is run AFTER the operations in i2c_init()
1568 is completed. This callpoint can be used to unreset i2c bus
1569 using CPU i2c controller register accesses for CPUs whose i2c
1570 controller provide such a method. It is called at the end of
1571 i2c_init() to allow i2c_init operations to setup the i2c bus
1572 controller on the CPU (e.g. setting bus speed & slave address).
1574 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1576 This option enables configuration of bi_iic_fast[] flags
1577 in u-boot bd_info structure based on u-boot environment
1578 variable "i2cfast". (see also i2cfast)
1580 CONFIG_I2C_MULTI_BUS
1582 This option allows the use of multiple I2C buses, each of which
1583 must have a controller. At any point in time, only one bus is
1584 active. To switch to a different bus, use the 'i2c dev' command.
1585 Note that bus numbering is zero-based.
1587 CONFIG_SYS_I2C_NOPROBES
1589 This option specifies a list of I2C devices that will be skipped
1590 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1591 is set, specify a list of bus-device pairs. Otherwise, specify
1592 a 1D array of device addresses
1595 #undef CONFIG_I2C_MULTI_BUS
1596 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1598 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1600 #define CONFIG_I2C_MULTI_BUS
1601 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1603 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1605 CONFIG_SYS_SPD_BUS_NUM
1607 If defined, then this indicates the I2C bus number for DDR SPD.
1608 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1610 CONFIG_SYS_RTC_BUS_NUM
1612 If defined, then this indicates the I2C bus number for the RTC.
1613 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1615 CONFIG_SYS_DTT_BUS_NUM
1617 If defined, then this indicates the I2C bus number for the DTT.
1618 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1620 CONFIG_SYS_I2C_DTT_ADDR:
1622 If defined, specifies the I2C address of the DTT device.
1623 If not defined, then U-Boot uses predefined value for
1624 specified DTT device.
1628 Define this option if you want to use Freescale's I2C driver in
1629 drivers/i2c/fsl_i2c.c.
1633 Define this option if you have I2C devices reached over 1 .. n
1634 I2C Muxes like the pca9544a. This option addes a new I2C
1635 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1636 new I2C Bus to the existing I2C Busses. If you select the
1637 new Bus with "i2c dev", u-bbot sends first the commandos for
1638 the muxes to activate this new "bus".
1640 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1644 Adding a new I2C Bus reached over 2 pca9544a muxes
1645 The First mux with address 70 and channel 6
1646 The Second mux with address 71 and channel 4
1648 => i2c bus pca9544a:70:6:pca9544a:71:4
1650 Use the "i2c bus" command without parameter, to get a list
1651 of I2C Busses with muxes:
1654 Busses reached over muxes:
1656 reached over Mux(es):
1659 reached over Mux(es):
1664 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1665 u-boot sends First the Commando to the mux@70 to enable
1666 channel 6, and then the Commando to the mux@71 to enable
1669 After that, you can use the "normal" i2c commands as
1670 usual, to communicate with your I2C devices behind
1673 This option is actually implemented for the bitbanging
1674 algorithm in common/soft_i2c.c and for the Hardware I2C
1675 Bus on the MPC8260. But it should be not so difficult
1676 to add this option to other architectures.
1678 CONFIG_SOFT_I2C_READ_REPEATED_START
1680 defining this will force the i2c_read() function in
1681 the soft_i2c driver to perform an I2C repeated start
1682 between writing the address pointer and reading the
1683 data. If this define is omitted the default behaviour
1684 of doing a stop-start sequence will be used. Most I2C
1685 devices can use either method, but some require one or
1688 - SPI Support: CONFIG_SPI
1690 Enables SPI driver (so far only tested with
1691 SPI EEPROM, also an instance works with Crystal A/D and
1692 D/As on the SACSng board)
1696 Enables the driver for SPI controller on SuperH. Currently
1697 only SH7757 is supported.
1701 Enables extended (16-bit) SPI EEPROM addressing.
1702 (symmetrical to CONFIG_I2C_X)
1706 Enables a software (bit-bang) SPI driver rather than
1707 using hardware support. This is a general purpose
1708 driver that only requires three general I/O port pins
1709 (two outputs, one input) to function. If this is
1710 defined, the board configuration must define several
1711 SPI configuration items (port pins to use, etc). For
1712 an example, see include/configs/sacsng.h.
1716 Enables a hardware SPI driver for general-purpose reads
1717 and writes. As with CONFIG_SOFT_SPI, the board configuration
1718 must define a list of chip-select function pointers.
1719 Currently supported on some MPC8xxx processors. For an
1720 example, see include/configs/mpc8349emds.h.
1724 Enables the driver for the SPI controllers on i.MX and MXC
1725 SoCs. Currently only i.MX31 is supported.
1727 - FPGA Support: CONFIG_FPGA
1729 Enables FPGA subsystem.
1731 CONFIG_FPGA_<vendor>
1733 Enables support for specific chip vendors.
1736 CONFIG_FPGA_<family>
1738 Enables support for FPGA family.
1739 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1743 Specify the number of FPGA devices to support.
1745 CONFIG_SYS_FPGA_PROG_FEEDBACK
1747 Enable printing of hash marks during FPGA configuration.
1749 CONFIG_SYS_FPGA_CHECK_BUSY
1751 Enable checks on FPGA configuration interface busy
1752 status by the configuration function. This option
1753 will require a board or device specific function to
1758 If defined, a function that provides delays in the FPGA
1759 configuration driver.
1761 CONFIG_SYS_FPGA_CHECK_CTRLC
1762 Allow Control-C to interrupt FPGA configuration
1764 CONFIG_SYS_FPGA_CHECK_ERROR
1766 Check for configuration errors during FPGA bitfile
1767 loading. For example, abort during Virtex II
1768 configuration if the INIT_B line goes low (which
1769 indicated a CRC error).
1771 CONFIG_SYS_FPGA_WAIT_INIT
1773 Maximum time to wait for the INIT_B line to deassert
1774 after PROB_B has been deasserted during a Virtex II
1775 FPGA configuration sequence. The default time is 500
1778 CONFIG_SYS_FPGA_WAIT_BUSY
1780 Maximum time to wait for BUSY to deassert during
1781 Virtex II FPGA configuration. The default is 5 ms.
1783 CONFIG_SYS_FPGA_WAIT_CONFIG
1785 Time to wait after FPGA configuration. The default is
1788 - Configuration Management:
1791 If defined, this string will be added to the U-Boot
1792 version information (U_BOOT_VERSION)
1794 - Vendor Parameter Protection:
1796 U-Boot considers the values of the environment
1797 variables "serial#" (Board Serial Number) and
1798 "ethaddr" (Ethernet Address) to be parameters that
1799 are set once by the board vendor / manufacturer, and
1800 protects these variables from casual modification by
1801 the user. Once set, these variables are read-only,
1802 and write or delete attempts are rejected. You can
1803 change this behaviour:
1805 If CONFIG_ENV_OVERWRITE is #defined in your config
1806 file, the write protection for vendor parameters is
1807 completely disabled. Anybody can change or delete
1810 Alternatively, if you #define _both_ CONFIG_ETHADDR
1811 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1812 Ethernet address is installed in the environment,
1813 which can be changed exactly ONCE by the user. [The
1814 serial# is unaffected by this, i. e. it remains
1820 Define this variable to enable the reservation of
1821 "protected RAM", i. e. RAM which is not overwritten
1822 by U-Boot. Define CONFIG_PRAM to hold the number of
1823 kB you want to reserve for pRAM. You can overwrite
1824 this default value by defining an environment
1825 variable "pram" to the number of kB you want to
1826 reserve. Note that the board info structure will
1827 still show the full amount of RAM. If pRAM is
1828 reserved, a new environment variable "mem" will
1829 automatically be defined to hold the amount of
1830 remaining RAM in a form that can be passed as boot
1831 argument to Linux, for instance like that:
1833 setenv bootargs ... mem=\${mem}
1836 This way you can tell Linux not to use this memory,
1837 either, which results in a memory region that will
1838 not be affected by reboots.
1840 *WARNING* If your board configuration uses automatic
1841 detection of the RAM size, you must make sure that
1842 this memory test is non-destructive. So far, the
1843 following board configurations are known to be
1846 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1847 HERMES, IP860, RPXlite, LWMON, LANTEC,
1853 Define this variable to stop the system in case of a
1854 fatal error, so that you have to reset it manually.
1855 This is probably NOT a good idea for an embedded
1856 system where you want the system to reboot
1857 automatically as fast as possible, but it may be
1858 useful during development since you can try to debug
1859 the conditions that lead to the situation.
1861 CONFIG_NET_RETRY_COUNT
1863 This variable defines the number of retries for
1864 network operations like ARP, RARP, TFTP, or BOOTP
1865 before giving up the operation. If not defined, a
1866 default value of 5 is used.
1870 Timeout waiting for an ARP reply in milliseconds.
1872 - Command Interpreter:
1873 CONFIG_AUTO_COMPLETE
1875 Enable auto completion of commands using TAB.
1877 Note that this feature has NOT been implemented yet
1878 for the "hush" shell.
1881 CONFIG_SYS_HUSH_PARSER
1883 Define this variable to enable the "hush" shell (from
1884 Busybox) as command line interpreter, thus enabling
1885 powerful command line syntax like
1886 if...then...else...fi conditionals or `&&' and '||'
1887 constructs ("shell scripts").
1889 If undefined, you get the old, much simpler behaviour
1890 with a somewhat smaller memory footprint.
1893 CONFIG_SYS_PROMPT_HUSH_PS2
1895 This defines the secondary prompt string, which is
1896 printed when the command interpreter needs more input
1897 to complete a command. Usually "> ".
1901 In the current implementation, the local variables
1902 space and global environment variables space are
1903 separated. Local variables are those you define by
1904 simply typing `name=value'. To access a local
1905 variable later on, you have write `$name' or
1906 `${name}'; to execute the contents of a variable
1907 directly type `$name' at the command prompt.
1909 Global environment variables are those you use
1910 setenv/printenv to work with. To run a command stored
1911 in such a variable, you need to use the run command,
1912 and you must not use the '$' sign to access them.
1914 To store commands and special characters in a
1915 variable, please use double quotation marks
1916 surrounding the whole text of the variable, instead
1917 of the backslashes before semicolons and special
1920 - Commandline Editing and History:
1921 CONFIG_CMDLINE_EDITING
1923 Enable editing and History functions for interactive
1924 commandline input operations
1926 - Default Environment:
1927 CONFIG_EXTRA_ENV_SETTINGS
1929 Define this to contain any number of null terminated
1930 strings (variable = value pairs) that will be part of
1931 the default environment compiled into the boot image.
1933 For example, place something like this in your
1934 board's config file:
1936 #define CONFIG_EXTRA_ENV_SETTINGS \
1940 Warning: This method is based on knowledge about the
1941 internal format how the environment is stored by the
1942 U-Boot code. This is NOT an official, exported
1943 interface! Although it is unlikely that this format
1944 will change soon, there is no guarantee either.
1945 You better know what you are doing here.
1947 Note: overly (ab)use of the default environment is
1948 discouraged. Make sure to check other ways to preset
1949 the environment like the "source" command or the
1952 - DataFlash Support:
1953 CONFIG_HAS_DATAFLASH
1955 Defining this option enables DataFlash features and
1956 allows to read/write in Dataflash via the standard
1959 - SystemACE Support:
1962 Adding this option adds support for Xilinx SystemACE
1963 chips attached via some sort of local bus. The address
1964 of the chip must also be defined in the
1965 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1967 #define CONFIG_SYSTEMACE
1968 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1970 When SystemACE support is added, the "ace" device type
1971 becomes available to the fat commands, i.e. fatls.
1973 - TFTP Fixed UDP Port:
1976 If this is defined, the environment variable tftpsrcp
1977 is used to supply the TFTP UDP source port value.
1978 If tftpsrcp isn't defined, the normal pseudo-random port
1979 number generator is used.
1981 Also, the environment variable tftpdstp is used to supply
1982 the TFTP UDP destination port value. If tftpdstp isn't
1983 defined, the normal port 69 is used.
1985 The purpose for tftpsrcp is to allow a TFTP server to
1986 blindly start the TFTP transfer using the pre-configured
1987 target IP address and UDP port. This has the effect of
1988 "punching through" the (Windows XP) firewall, allowing
1989 the remainder of the TFTP transfer to proceed normally.
1990 A better solution is to properly configure the firewall,
1991 but sometimes that is not allowed.
1993 - Show boot progress:
1994 CONFIG_SHOW_BOOT_PROGRESS
1996 Defining this option allows to add some board-
1997 specific code (calling a user-provided function
1998 "show_boot_progress(int)") that enables you to show
1999 the system's boot progress on some display (for
2000 example, some LED's) on your board. At the moment,
2001 the following checkpoints are implemented:
2003 - Standalone program support:
2004 CONFIG_STANDALONE_LOAD_ADDR
2006 This option allows to define board specific values
2007 for the address where standalone program gets loaded,
2008 thus overwriting the architecutre dependent default
2011 Legacy uImage format:
2014 1 common/cmd_bootm.c before attempting to boot an image
2015 -1 common/cmd_bootm.c Image header has bad magic number
2016 2 common/cmd_bootm.c Image header has correct magic number
2017 -2 common/cmd_bootm.c Image header has bad checksum
2018 3 common/cmd_bootm.c Image header has correct checksum
2019 -3 common/cmd_bootm.c Image data has bad checksum
2020 4 common/cmd_bootm.c Image data has correct checksum
2021 -4 common/cmd_bootm.c Image is for unsupported architecture
2022 5 common/cmd_bootm.c Architecture check OK
2023 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2024 6 common/cmd_bootm.c Image Type check OK
2025 -6 common/cmd_bootm.c gunzip uncompression error
2026 -7 common/cmd_bootm.c Unimplemented compression type
2027 7 common/cmd_bootm.c Uncompression OK
2028 8 common/cmd_bootm.c No uncompress/copy overwrite error
2029 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2031 9 common/image.c Start initial ramdisk verification
2032 -10 common/image.c Ramdisk header has bad magic number
2033 -11 common/image.c Ramdisk header has bad checksum
2034 10 common/image.c Ramdisk header is OK
2035 -12 common/image.c Ramdisk data has bad checksum
2036 11 common/image.c Ramdisk data has correct checksum
2037 12 common/image.c Ramdisk verification complete, start loading
2038 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2039 13 common/image.c Start multifile image verification
2040 14 common/image.c No initial ramdisk, no multifile, continue.
2042 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2044 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2045 -31 post/post.c POST test failed, detected by post_output_backlog()
2046 -32 post/post.c POST test failed, detected by post_run_single()
2048 34 common/cmd_doc.c before loading a Image from a DOC device
2049 -35 common/cmd_doc.c Bad usage of "doc" command
2050 35 common/cmd_doc.c correct usage of "doc" command
2051 -36 common/cmd_doc.c No boot device
2052 36 common/cmd_doc.c correct boot device
2053 -37 common/cmd_doc.c Unknown Chip ID on boot device
2054 37 common/cmd_doc.c correct chip ID found, device available
2055 -38 common/cmd_doc.c Read Error on boot device
2056 38 common/cmd_doc.c reading Image header from DOC device OK
2057 -39 common/cmd_doc.c Image header has bad magic number
2058 39 common/cmd_doc.c Image header has correct magic number
2059 -40 common/cmd_doc.c Error reading Image from DOC device
2060 40 common/cmd_doc.c Image header has correct magic number
2061 41 common/cmd_ide.c before loading a Image from a IDE device
2062 -42 common/cmd_ide.c Bad usage of "ide" command
2063 42 common/cmd_ide.c correct usage of "ide" command
2064 -43 common/cmd_ide.c No boot device
2065 43 common/cmd_ide.c boot device found
2066 -44 common/cmd_ide.c Device not available
2067 44 common/cmd_ide.c Device available
2068 -45 common/cmd_ide.c wrong partition selected
2069 45 common/cmd_ide.c partition selected
2070 -46 common/cmd_ide.c Unknown partition table
2071 46 common/cmd_ide.c valid partition table found
2072 -47 common/cmd_ide.c Invalid partition type
2073 47 common/cmd_ide.c correct partition type
2074 -48 common/cmd_ide.c Error reading Image Header on boot device
2075 48 common/cmd_ide.c reading Image Header from IDE device OK
2076 -49 common/cmd_ide.c Image header has bad magic number
2077 49 common/cmd_ide.c Image header has correct magic number
2078 -50 common/cmd_ide.c Image header has bad checksum
2079 50 common/cmd_ide.c Image header has correct checksum
2080 -51 common/cmd_ide.c Error reading Image from IDE device
2081 51 common/cmd_ide.c reading Image from IDE device OK
2082 52 common/cmd_nand.c before loading a Image from a NAND device
2083 -53 common/cmd_nand.c Bad usage of "nand" command
2084 53 common/cmd_nand.c correct usage of "nand" command
2085 -54 common/cmd_nand.c No boot device
2086 54 common/cmd_nand.c boot device found
2087 -55 common/cmd_nand.c Unknown Chip ID on boot device
2088 55 common/cmd_nand.c correct chip ID found, device available
2089 -56 common/cmd_nand.c Error reading Image Header on boot device
2090 56 common/cmd_nand.c reading Image Header from NAND device OK
2091 -57 common/cmd_nand.c Image header has bad magic number
2092 57 common/cmd_nand.c Image header has correct magic number
2093 -58 common/cmd_nand.c Error reading Image from NAND device
2094 58 common/cmd_nand.c reading Image from NAND device OK
2096 -60 common/env_common.c Environment has a bad CRC, using default
2098 64 net/eth.c starting with Ethernet configuration.
2099 -64 net/eth.c no Ethernet found.
2100 65 net/eth.c Ethernet found.
2102 -80 common/cmd_net.c usage wrong
2103 80 common/cmd_net.c before calling NetLoop()
2104 -81 common/cmd_net.c some error in NetLoop() occurred
2105 81 common/cmd_net.c NetLoop() back without error
2106 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2107 82 common/cmd_net.c trying automatic boot
2108 83 common/cmd_net.c running "source" command
2109 -83 common/cmd_net.c some error in automatic boot or "source" command
2110 84 common/cmd_net.c end without errors
2115 100 common/cmd_bootm.c Kernel FIT Image has correct format
2116 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2117 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2118 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2119 102 common/cmd_bootm.c Kernel unit name specified
2120 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2121 103 common/cmd_bootm.c Found configuration node
2122 104 common/cmd_bootm.c Got kernel subimage node offset
2123 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2124 105 common/cmd_bootm.c Kernel subimage hash verification OK
2125 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2126 106 common/cmd_bootm.c Architecture check OK
2127 -106 common/cmd_bootm.c Kernel subimage has wrong type
2128 107 common/cmd_bootm.c Kernel subimage type OK
2129 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2130 108 common/cmd_bootm.c Got kernel subimage data/size
2131 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2132 -109 common/cmd_bootm.c Can't get kernel subimage type
2133 -110 common/cmd_bootm.c Can't get kernel subimage comp
2134 -111 common/cmd_bootm.c Can't get kernel subimage os
2135 -112 common/cmd_bootm.c Can't get kernel subimage load address
2136 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2138 120 common/image.c Start initial ramdisk verification
2139 -120 common/image.c Ramdisk FIT image has incorrect format
2140 121 common/image.c Ramdisk FIT image has correct format
2141 122 common/image.c No ramdisk subimage unit name, using configuration
2142 -122 common/image.c Can't get configuration for ramdisk subimage
2143 123 common/image.c Ramdisk unit name specified
2144 -124 common/image.c Can't get ramdisk subimage node offset
2145 125 common/image.c Got ramdisk subimage node offset
2146 -125 common/image.c Ramdisk subimage hash verification failed
2147 126 common/image.c Ramdisk subimage hash verification OK
2148 -126 common/image.c Ramdisk subimage for unsupported architecture
2149 127 common/image.c Architecture check OK
2150 -127 common/image.c Can't get ramdisk subimage data/size
2151 128 common/image.c Got ramdisk subimage data/size
2152 129 common/image.c Can't get ramdisk load address
2153 -129 common/image.c Got ramdisk load address
2155 -130 common/cmd_doc.c Incorrect FIT image format
2156 131 common/cmd_doc.c FIT image format OK
2158 -140 common/cmd_ide.c Incorrect FIT image format
2159 141 common/cmd_ide.c FIT image format OK
2161 -150 common/cmd_nand.c Incorrect FIT image format
2162 151 common/cmd_nand.c FIT image format OK
2164 - Automatic software updates via TFTP server
2166 CONFIG_UPDATE_TFTP_CNT_MAX
2167 CONFIG_UPDATE_TFTP_MSEC_MAX
2169 These options enable and control the auto-update feature;
2170 for a more detailed description refer to doc/README.update.
2172 - MTD Support (mtdparts command, UBI support)
2175 Adds the MTD device infrastructure from the Linux kernel.
2176 Needed for mtdparts command support.
2178 CONFIG_MTD_PARTITIONS
2180 Adds the MTD partitioning infrastructure from the Linux
2181 kernel. Needed for UBI support.
2187 [so far only for SMDK2400 and TRAB boards]
2189 - Modem support enable:
2190 CONFIG_MODEM_SUPPORT
2192 - RTS/CTS Flow control enable:
2195 - Modem debug support:
2196 CONFIG_MODEM_SUPPORT_DEBUG
2198 Enables debugging stuff (char screen[1024], dbg())
2199 for modem support. Useful only with BDI2000.
2201 - Interrupt support (PPC):
2203 There are common interrupt_init() and timer_interrupt()
2204 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2205 for CPU specific initialization. interrupt_init_cpu()
2206 should set decrementer_count to appropriate value. If
2207 CPU resets decrementer automatically after interrupt
2208 (ppc4xx) it should set decrementer_count to zero.
2209 timer_interrupt() calls timer_interrupt_cpu() for CPU
2210 specific handling. If board has watchdog / status_led
2211 / other_activity_monitor it works automatically from
2212 general timer_interrupt().
2216 In the target system modem support is enabled when a
2217 specific key (key combination) is pressed during
2218 power-on. Otherwise U-Boot will boot normally
2219 (autoboot). The key_pressed() function is called from
2220 board_init(). Currently key_pressed() is a dummy
2221 function, returning 1 and thus enabling modem
2224 If there are no modem init strings in the
2225 environment, U-Boot proceed to autoboot; the
2226 previous output (banner, info printfs) will be
2229 See also: doc/README.Modem
2232 Configuration Settings:
2233 -----------------------
2235 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2236 undefine this when you're short of memory.
2238 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2239 width of the commands listed in the 'help' command output.
2241 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2242 prompt for user input.
2244 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2246 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2248 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2250 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2251 the application (usually a Linux kernel) when it is
2254 - CONFIG_SYS_BAUDRATE_TABLE:
2255 List of legal baudrate settings for this board.
2257 - CONFIG_SYS_CONSOLE_INFO_QUIET
2258 Suppress display of console information at boot.
2260 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2261 If the board specific function
2262 extern int overwrite_console (void);
2263 returns 1, the stdin, stderr and stdout are switched to the
2264 serial port, else the settings in the environment are used.
2266 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2267 Enable the call to overwrite_console().
2269 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2270 Enable overwrite of previous console environment settings.
2272 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2273 Begin and End addresses of the area used by the
2276 - CONFIG_SYS_ALT_MEMTEST:
2277 Enable an alternate, more extensive memory test.
2279 - CONFIG_SYS_MEMTEST_SCRATCH:
2280 Scratch address used by the alternate memory test
2281 You only need to set this if address zero isn't writeable
2283 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2284 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2285 this specified memory area will get subtracted from the top
2286 (end) of RAM and won't get "touched" at all by U-Boot. By
2287 fixing up gd->ram_size the Linux kernel should gets passed
2288 the now "corrected" memory size and won't touch it either.
2289 This should work for arch/ppc and arch/powerpc. Only Linux
2290 board ports in arch/powerpc with bootwrapper support that
2291 recalculate the memory size from the SDRAM controller setup
2292 will have to get fixed in Linux additionally.
2294 This option can be used as a workaround for the 440EPx/GRx
2295 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2298 WARNING: Please make sure that this value is a multiple of
2299 the Linux page size (normally 4k). If this is not the case,
2300 then the end address of the Linux memory will be located at a
2301 non page size aligned address and this could cause major
2304 - CONFIG_SYS_TFTP_LOADADDR:
2305 Default load address for network file downloads
2307 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2308 Enable temporary baudrate change while serial download
2310 - CONFIG_SYS_SDRAM_BASE:
2311 Physical start address of SDRAM. _Must_ be 0 here.
2313 - CONFIG_SYS_MBIO_BASE:
2314 Physical start address of Motherboard I/O (if using a
2317 - CONFIG_SYS_FLASH_BASE:
2318 Physical start address of Flash memory.
2320 - CONFIG_SYS_MONITOR_BASE:
2321 Physical start address of boot monitor code (set by
2322 make config files to be same as the text base address
2323 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2324 CONFIG_SYS_FLASH_BASE when booting from flash.
2326 - CONFIG_SYS_MONITOR_LEN:
2327 Size of memory reserved for monitor code, used to
2328 determine _at_compile_time_ (!) if the environment is
2329 embedded within the U-Boot image, or in a separate
2332 - CONFIG_SYS_MALLOC_LEN:
2333 Size of DRAM reserved for malloc() use.
2335 - CONFIG_SYS_BOOTM_LEN:
2336 Normally compressed uImages are limited to an
2337 uncompressed size of 8 MBytes. If this is not enough,
2338 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2339 to adjust this setting to your needs.
2341 - CONFIG_SYS_BOOTMAPSZ:
2342 Maximum size of memory mapped by the startup code of
2343 the Linux kernel; all data that must be processed by
2344 the Linux kernel (bd_info, boot arguments, FDT blob if
2345 used) must be put below this limit, unless "bootm_low"
2346 enviroment variable is defined and non-zero. In such case
2347 all data for the Linux kernel must be between "bootm_low"
2348 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2350 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2351 Enable initrd_high functionality. If defined then the
2352 initrd_high feature is enabled and the bootm ramdisk subcommand
2355 - CONFIG_SYS_BOOT_GET_CMDLINE:
2356 Enables allocating and saving kernel cmdline in space between
2357 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2359 - CONFIG_SYS_BOOT_GET_KBD:
2360 Enables allocating and saving a kernel copy of the bd_info in
2361 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2363 - CONFIG_SYS_MAX_FLASH_BANKS:
2364 Max number of Flash memory banks
2366 - CONFIG_SYS_MAX_FLASH_SECT:
2367 Max number of sectors on a Flash chip
2369 - CONFIG_SYS_FLASH_ERASE_TOUT:
2370 Timeout for Flash erase operations (in ms)
2372 - CONFIG_SYS_FLASH_WRITE_TOUT:
2373 Timeout for Flash write operations (in ms)
2375 - CONFIG_SYS_FLASH_LOCK_TOUT
2376 Timeout for Flash set sector lock bit operation (in ms)
2378 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2379 Timeout for Flash clear lock bits operation (in ms)
2381 - CONFIG_SYS_FLASH_PROTECTION
2382 If defined, hardware flash sectors protection is used
2383 instead of U-Boot software protection.
2385 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2387 Enable TFTP transfers directly to flash memory;
2388 without this option such a download has to be
2389 performed in two steps: (1) download to RAM, and (2)
2390 copy from RAM to flash.
2392 The two-step approach is usually more reliable, since
2393 you can check if the download worked before you erase
2394 the flash, but in some situations (when system RAM is
2395 too limited to allow for a temporary copy of the
2396 downloaded image) this option may be very useful.
2398 - CONFIG_SYS_FLASH_CFI:
2399 Define if the flash driver uses extra elements in the
2400 common flash structure for storing flash geometry.
2402 - CONFIG_FLASH_CFI_DRIVER
2403 This option also enables the building of the cfi_flash driver
2404 in the drivers directory
2406 - CONFIG_FLASH_CFI_MTD
2407 This option enables the building of the cfi_mtd driver
2408 in the drivers directory. The driver exports CFI flash
2411 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2412 Use buffered writes to flash.
2414 - CONFIG_FLASH_SPANSION_S29WS_N
2415 s29ws-n MirrorBit flash has non-standard addresses for buffered
2418 - CONFIG_SYS_FLASH_QUIET_TEST
2419 If this option is defined, the common CFI flash doesn't
2420 print it's warning upon not recognized FLASH banks. This
2421 is useful, if some of the configured banks are only
2422 optionally available.
2424 - CONFIG_FLASH_SHOW_PROGRESS
2425 If defined (must be an integer), print out countdown
2426 digits and dots. Recommended value: 45 (9..1) for 80
2427 column displays, 15 (3..1) for 40 column displays.
2429 - CONFIG_SYS_RX_ETH_BUFFER:
2430 Defines the number of Ethernet receive buffers. On some
2431 Ethernet controllers it is recommended to set this value
2432 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2433 buffers can be full shortly after enabling the interface
2434 on high Ethernet traffic.
2435 Defaults to 4 if not defined.
2437 - CONFIG_ENV_MAX_ENTRIES
2439 Maximum number of entries in the hash table that is used
2440 internally to store the environment settings. The default
2441 setting is supposed to be generous and should work in most
2442 cases. This setting can be used to tune behaviour; see
2443 lib/hashtable.c for details.
2445 The following definitions that deal with the placement and management
2446 of environment data (variable area); in general, we support the
2447 following configurations:
2449 - CONFIG_ENV_IS_IN_FLASH:
2451 Define this if the environment is in flash memory.
2453 a) The environment occupies one whole flash sector, which is
2454 "embedded" in the text segment with the U-Boot code. This
2455 happens usually with "bottom boot sector" or "top boot
2456 sector" type flash chips, which have several smaller
2457 sectors at the start or the end. For instance, such a
2458 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2459 such a case you would place the environment in one of the
2460 4 kB sectors - with U-Boot code before and after it. With
2461 "top boot sector" type flash chips, you would put the
2462 environment in one of the last sectors, leaving a gap
2463 between U-Boot and the environment.
2465 - CONFIG_ENV_OFFSET:
2467 Offset of environment data (variable area) to the
2468 beginning of flash memory; for instance, with bottom boot
2469 type flash chips the second sector can be used: the offset
2470 for this sector is given here.
2472 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2476 This is just another way to specify the start address of
2477 the flash sector containing the environment (instead of
2480 - CONFIG_ENV_SECT_SIZE:
2482 Size of the sector containing the environment.
2485 b) Sometimes flash chips have few, equal sized, BIG sectors.
2486 In such a case you don't want to spend a whole sector for
2491 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2492 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2493 of this flash sector for the environment. This saves
2494 memory for the RAM copy of the environment.
2496 It may also save flash memory if you decide to use this
2497 when your environment is "embedded" within U-Boot code,
2498 since then the remainder of the flash sector could be used
2499 for U-Boot code. It should be pointed out that this is
2500 STRONGLY DISCOURAGED from a robustness point of view:
2501 updating the environment in flash makes it always
2502 necessary to erase the WHOLE sector. If something goes
2503 wrong before the contents has been restored from a copy in
2504 RAM, your target system will be dead.
2506 - CONFIG_ENV_ADDR_REDUND
2507 CONFIG_ENV_SIZE_REDUND
2509 These settings describe a second storage area used to hold
2510 a redundant copy of the environment data, so that there is
2511 a valid backup copy in case there is a power failure during
2512 a "saveenv" operation.
2514 BE CAREFUL! Any changes to the flash layout, and some changes to the
2515 source code will make it necessary to adapt <board>/u-boot.lds*
2519 - CONFIG_ENV_IS_IN_NVRAM:
2521 Define this if you have some non-volatile memory device
2522 (NVRAM, battery buffered SRAM) which you want to use for the
2528 These two #defines are used to determine the memory area you
2529 want to use for environment. It is assumed that this memory
2530 can just be read and written to, without any special
2533 BE CAREFUL! The first access to the environment happens quite early
2534 in U-Boot initalization (when we try to get the setting of for the
2535 console baudrate). You *MUST* have mapped your NVRAM area then, or
2538 Please note that even with NVRAM we still use a copy of the
2539 environment in RAM: we could work on NVRAM directly, but we want to
2540 keep settings there always unmodified except somebody uses "saveenv"
2541 to save the current settings.
2544 - CONFIG_ENV_IS_IN_EEPROM:
2546 Use this if you have an EEPROM or similar serial access
2547 device and a driver for it.
2549 - CONFIG_ENV_OFFSET:
2552 These two #defines specify the offset and size of the
2553 environment area within the total memory of your EEPROM.
2555 - CONFIG_SYS_I2C_EEPROM_ADDR:
2556 If defined, specified the chip address of the EEPROM device.
2557 The default address is zero.
2559 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2560 If defined, the number of bits used to address bytes in a
2561 single page in the EEPROM device. A 64 byte page, for example
2562 would require six bits.
2564 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2565 If defined, the number of milliseconds to delay between
2566 page writes. The default is zero milliseconds.
2568 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2569 The length in bytes of the EEPROM memory array address. Note
2570 that this is NOT the chip address length!
2572 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2573 EEPROM chips that implement "address overflow" are ones
2574 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2575 address and the extra bits end up in the "chip address" bit
2576 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2579 Note that we consider the length of the address field to
2580 still be one byte because the extra address bits are hidden
2581 in the chip address.
2583 - CONFIG_SYS_EEPROM_SIZE:
2584 The size in bytes of the EEPROM device.
2586 - CONFIG_ENV_EEPROM_IS_ON_I2C
2587 define this, if you have I2C and SPI activated, and your
2588 EEPROM, which holds the environment, is on the I2C bus.
2590 - CONFIG_I2C_ENV_EEPROM_BUS
2591 if you have an Environment on an EEPROM reached over
2592 I2C muxes, you can define here, how to reach this
2593 EEPROM. For example:
2595 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2597 EEPROM which holds the environment, is reached over
2598 a pca9547 i2c mux with address 0x70, channel 3.
2600 - CONFIG_ENV_IS_IN_DATAFLASH:
2602 Define this if you have a DataFlash memory device which you
2603 want to use for the environment.
2605 - CONFIG_ENV_OFFSET:
2609 These three #defines specify the offset and size of the
2610 environment area within the total memory of your DataFlash placed
2611 at the specified address.
2613 - CONFIG_ENV_IS_IN_NAND:
2615 Define this if you have a NAND device which you want to use
2616 for the environment.
2618 - CONFIG_ENV_OFFSET:
2621 These two #defines specify the offset and size of the environment
2622 area within the first NAND device. CONFIG_ENV_OFFSET must be
2623 aligned to an erase block boundary.
2625 - CONFIG_ENV_OFFSET_REDUND (optional):
2627 This setting describes a second storage area of CONFIG_ENV_SIZE
2628 size used to hold a redundant copy of the environment data, so
2629 that there is a valid backup copy in case there is a power failure
2630 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2631 aligned to an erase block boundary.
2633 - CONFIG_ENV_RANGE (optional):
2635 Specifies the length of the region in which the environment
2636 can be written. This should be a multiple of the NAND device's
2637 block size. Specifying a range with more erase blocks than
2638 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2639 the range to be avoided.
2641 - CONFIG_ENV_OFFSET_OOB (optional):
2643 Enables support for dynamically retrieving the offset of the
2644 environment from block zero's out-of-band data. The
2645 "nand env.oob" command can be used to record this offset.
2646 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2647 using CONFIG_ENV_OFFSET_OOB.
2649 - CONFIG_NAND_ENV_DST
2651 Defines address in RAM to which the nand_spl code should copy the
2652 environment. If redundant environment is used, it will be copied to
2653 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2655 - CONFIG_SYS_SPI_INIT_OFFSET
2657 Defines offset to the initial SPI buffer area in DPRAM. The
2658 area is used at an early stage (ROM part) if the environment
2659 is configured to reside in the SPI EEPROM: We need a 520 byte
2660 scratch DPRAM area. It is used between the two initialization
2661 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2662 to be a good choice since it makes it far enough from the
2663 start of the data area as well as from the stack pointer.
2665 Please note that the environment is read-only until the monitor
2666 has been relocated to RAM and a RAM copy of the environment has been
2667 created; also, when using EEPROM you will have to use getenv_f()
2668 until then to read environment variables.
2670 The environment is protected by a CRC32 checksum. Before the monitor
2671 is relocated into RAM, as a result of a bad CRC you will be working
2672 with the compiled-in default environment - *silently*!!! [This is
2673 necessary, because the first environment variable we need is the
2674 "baudrate" setting for the console - if we have a bad CRC, we don't
2675 have any device yet where we could complain.]
2677 Note: once the monitor has been relocated, then it will complain if
2678 the default environment is used; a new CRC is computed as soon as you
2679 use the "saveenv" command to store a valid environment.
2681 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2682 Echo the inverted Ethernet link state to the fault LED.
2684 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2685 also needs to be defined.
2687 - CONFIG_SYS_FAULT_MII_ADDR:
2688 MII address of the PHY to check for the Ethernet link state.
2690 - CONFIG_NS16550_MIN_FUNCTIONS:
2691 Define this if you desire to only have use of the NS16550_init
2692 and NS16550_putc functions for the serial driver located at
2693 drivers/serial/ns16550.c. This option is useful for saving
2694 space for already greatly restricted images, including but not
2695 limited to NAND_SPL configurations.
2697 Low Level (hardware related) configuration options:
2698 ---------------------------------------------------
2700 - CONFIG_SYS_CACHELINE_SIZE:
2701 Cache Line Size of the CPU.
2703 - CONFIG_SYS_DEFAULT_IMMR:
2704 Default address of the IMMR after system reset.
2706 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2707 and RPXsuper) to be able to adjust the position of
2708 the IMMR register after a reset.
2710 - Floppy Disk Support:
2711 CONFIG_SYS_FDC_DRIVE_NUMBER
2713 the default drive number (default value 0)
2715 CONFIG_SYS_ISA_IO_STRIDE
2717 defines the spacing between FDC chipset registers
2720 CONFIG_SYS_ISA_IO_OFFSET
2722 defines the offset of register from address. It
2723 depends on which part of the data bus is connected to
2724 the FDC chipset. (default value 0)
2726 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2727 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2730 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2731 fdc_hw_init() is called at the beginning of the FDC
2732 setup. fdc_hw_init() must be provided by the board
2733 source code. It is used to make hardware dependant
2736 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2737 DO NOT CHANGE unless you know exactly what you're
2738 doing! (11-4) [MPC8xx/82xx systems only]
2740 - CONFIG_SYS_INIT_RAM_ADDR:
2742 Start address of memory area that can be used for
2743 initial data and stack; please note that this must be
2744 writable memory that is working WITHOUT special
2745 initialization, i. e. you CANNOT use normal RAM which
2746 will become available only after programming the
2747 memory controller and running certain initialization
2750 U-Boot uses the following memory types:
2751 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2752 - MPC824X: data cache
2753 - PPC4xx: data cache
2755 - CONFIG_SYS_GBL_DATA_OFFSET:
2757 Offset of the initial data structure in the memory
2758 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2759 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2760 data is located at the end of the available space
2761 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2762 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2763 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2764 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2767 On the MPC824X (or other systems that use the data
2768 cache for initial memory) the address chosen for
2769 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2770 point to an otherwise UNUSED address space between
2771 the top of RAM and the start of the PCI space.
2773 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2775 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2777 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2779 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2781 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2783 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2785 - CONFIG_SYS_OR_TIMING_SDRAM:
2788 - CONFIG_SYS_MAMR_PTA:
2789 periodic timer for refresh
2791 - CONFIG_SYS_DER: Debug Event Register (37-47)
2793 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2794 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2795 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2796 CONFIG_SYS_BR1_PRELIM:
2797 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2799 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2800 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2801 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2802 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2804 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2805 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2806 Machine Mode Register and Memory Periodic Timer
2807 Prescaler definitions (SDRAM timing)
2809 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2810 enable I2C microcode relocation patch (MPC8xx);
2811 define relocation offset in DPRAM [DSP2]
2813 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2814 enable SMC microcode relocation patch (MPC8xx);
2815 define relocation offset in DPRAM [SMC1]
2817 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2818 enable SPI microcode relocation patch (MPC8xx);
2819 define relocation offset in DPRAM [SCC4]
2821 - CONFIG_SYS_USE_OSCCLK:
2822 Use OSCM clock mode on MBX8xx board. Be careful,
2823 wrong setting might damage your board. Read
2824 doc/README.MBX before setting this variable!
2826 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2827 Offset of the bootmode word in DPRAM used by post
2828 (Power On Self Tests). This definition overrides
2829 #define'd default value in commproc.h resp.
2832 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2833 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2834 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2835 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2836 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2837 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2838 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2839 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2840 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
2842 - CONFIG_PCI_DISABLE_PCIE:
2843 Disable PCI-Express on systems where it is supported but not
2847 Chip has SRIO or not
2850 Board has SRIO 1 port available
2853 Board has SRIO 2 port available
2855 - CONFIG_SYS_SRIOn_MEM_VIRT:
2856 Virtual Address of SRIO port 'n' memory region
2858 - CONFIG_SYS_SRIOn_MEM_PHYS:
2859 Physical Address of SRIO port 'n' memory region
2861 - CONFIG_SYS_SRIOn_MEM_SIZE:
2862 Size of SRIO port 'n' memory region
2865 Get DDR timing information from an I2C EEPROM. Common
2866 with pluggable memory modules such as SODIMMs
2869 I2C address of the SPD EEPROM
2871 - CONFIG_SYS_SPD_BUS_NUM
2872 If SPD EEPROM is on an I2C bus other than the first
2873 one, specify here. Note that the value must resolve
2874 to something your driver can deal with.
2876 - CONFIG_SYS_83XX_DDR_USES_CS0
2877 Only for 83xx systems. If specified, then DDR should
2878 be configured using CS0 and CS1 instead of CS2 and CS3.
2880 - CONFIG_ETHER_ON_FEC[12]
2881 Define to enable FEC[12] on a 8xx series processor.
2883 - CONFIG_FEC[12]_PHY
2884 Define to the hardcoded PHY address which corresponds
2885 to the given FEC; i. e.
2886 #define CONFIG_FEC1_PHY 4
2887 means that the PHY with address 4 is connected to FEC1
2889 When set to -1, means to probe for first available.
2891 - CONFIG_FEC[12]_PHY_NORXERR
2892 The PHY does not have a RXERR line (RMII only).
2893 (so program the FEC to ignore it).
2896 Enable RMII mode for all FECs.
2897 Note that this is a global option, we can't
2898 have one FEC in standard MII mode and another in RMII mode.
2900 - CONFIG_CRC32_VERIFY
2901 Add a verify option to the crc32 command.
2904 => crc32 -v <address> <count> <crc32>
2906 Where address/count indicate a memory area
2907 and crc32 is the correct crc32 which the
2911 Add the "loopw" memory command. This only takes effect if
2912 the memory commands are activated globally (CONFIG_CMD_MEM).
2915 Add the "mdc" and "mwc" memory commands. These are cyclic
2920 This command will print 4 bytes (10,11,12,13) each 500 ms.
2922 => mwc.l 100 12345678 10
2923 This command will write 12345678 to address 100 all 10 ms.
2925 This only takes effect if the memory commands are activated
2926 globally (CONFIG_CMD_MEM).
2928 - CONFIG_SKIP_LOWLEVEL_INIT
2929 [ARM only] If this variable is defined, then certain
2930 low level initializations (like setting up the memory
2931 controller) are omitted and/or U-Boot does not
2932 relocate itself into RAM.
2934 Normally this variable MUST NOT be defined. The only
2935 exception is when U-Boot is loaded (to RAM) by some
2936 other boot loader or by a debugger which performs
2937 these initializations itself.
2940 Modifies the behaviour of start.S when compiling a loader
2941 that is executed before the actual U-Boot. E.g. when
2942 compiling a NAND SPL.
2944 Building the Software:
2945 ======================
2947 Building U-Boot has been tested in several native build environments
2948 and in many different cross environments. Of course we cannot support
2949 all possibly existing versions of cross development tools in all
2950 (potentially obsolete) versions. In case of tool chain problems we
2951 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2952 which is extensively used to build and test U-Boot.
2954 If you are not using a native environment, it is assumed that you
2955 have GNU cross compiling tools available in your path. In this case,
2956 you must set the environment variable CROSS_COMPILE in your shell.
2957 Note that no changes to the Makefile or any other source files are
2958 necessary. For example using the ELDK on a 4xx CPU, please enter:
2960 $ CROSS_COMPILE=ppc_4xx-
2961 $ export CROSS_COMPILE
2963 Note: If you wish to generate Windows versions of the utilities in
2964 the tools directory you can use the MinGW toolchain
2965 (http://www.mingw.org). Set your HOST tools to the MinGW
2966 toolchain and execute 'make tools'. For example:
2968 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
2970 Binaries such as tools/mkimage.exe will be created which can
2971 be executed on computers running Windows.
2973 U-Boot is intended to be simple to build. After installing the
2974 sources you must configure U-Boot for one specific board type. This
2979 where "NAME_config" is the name of one of the existing configu-
2980 rations; see the main Makefile for supported names.
2982 Note: for some board special configuration names may exist; check if
2983 additional information is available from the board vendor; for
2984 instance, the TQM823L systems are available without (standard)
2985 or with LCD support. You can select such additional "features"
2986 when choosing the configuration, i. e.
2989 - will configure for a plain TQM823L, i. e. no LCD support
2991 make TQM823L_LCD_config
2992 - will configure for a TQM823L with U-Boot console on LCD
2997 Finally, type "make all", and you should get some working U-Boot
2998 images ready for download to / installation on your system:
3000 - "u-boot.bin" is a raw binary image
3001 - "u-boot" is an image in ELF binary format
3002 - "u-boot.srec" is in Motorola S-Record format
3004 By default the build is performed locally and the objects are saved
3005 in the source directory. One of the two methods can be used to change
3006 this behavior and build U-Boot to some external directory:
3008 1. Add O= to the make command line invocations:
3010 make O=/tmp/build distclean
3011 make O=/tmp/build NAME_config
3012 make O=/tmp/build all
3014 2. Set environment variable BUILD_DIR to point to the desired location:
3016 export BUILD_DIR=/tmp/build
3021 Note that the command line "O=" setting overrides the BUILD_DIR environment
3025 Please be aware that the Makefiles assume you are using GNU make, so
3026 for instance on NetBSD you might need to use "gmake" instead of
3030 If the system board that you have is not listed, then you will need
3031 to port U-Boot to your hardware platform. To do this, follow these
3034 1. Add a new configuration option for your board to the toplevel
3035 "Makefile" and to the "MAKEALL" script, using the existing
3036 entries as examples. Note that here and at many other places
3037 boards and other names are listed in alphabetical sort order. Please
3039 2. Create a new directory to hold your board specific code. Add any
3040 files you need. In your board directory, you will need at least
3041 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3042 3. Create a new configuration file "include/configs/<board>.h" for
3044 3. If you're porting U-Boot to a new CPU, then also create a new
3045 directory to hold your CPU specific code. Add any files you need.
3046 4. Run "make <board>_config" with your new name.
3047 5. Type "make", and you should get a working "u-boot.srec" file
3048 to be installed on your target system.
3049 6. Debug and solve any problems that might arise.
3050 [Of course, this last step is much harder than it sounds.]
3053 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3054 ==============================================================
3056 If you have modified U-Boot sources (for instance added a new board
3057 or support for new devices, a new CPU, etc.) you are expected to
3058 provide feedback to the other developers. The feedback normally takes
3059 the form of a "patch", i. e. a context diff against a certain (latest
3060 official or latest in the git repository) version of U-Boot sources.
3062 But before you submit such a patch, please verify that your modifi-
3063 cation did not break existing code. At least make sure that *ALL* of
3064 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3065 just run the "MAKEALL" script, which will configure and build U-Boot
3066 for ALL supported system. Be warned, this will take a while. You can
3067 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3068 environment variable to the script, i. e. to use the ELDK cross tools
3071 CROSS_COMPILE=ppc_8xx- MAKEALL
3073 or to build on a native PowerPC system you can type
3075 CROSS_COMPILE=' ' MAKEALL
3077 When using the MAKEALL script, the default behaviour is to build
3078 U-Boot in the source directory. This location can be changed by
3079 setting the BUILD_DIR environment variable. Also, for each target
3080 built, the MAKEALL script saves two log files (<target>.ERR and
3081 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3082 location can be changed by setting the MAKEALL_LOGDIR environment
3083 variable. For example:
3085 export BUILD_DIR=/tmp/build
3086 export MAKEALL_LOGDIR=/tmp/log
3087 CROSS_COMPILE=ppc_8xx- MAKEALL
3089 With the above settings build objects are saved in the /tmp/build,
3090 log files are saved in the /tmp/log and the source tree remains clean
3091 during the whole build process.
3094 See also "U-Boot Porting Guide" below.
3097 Monitor Commands - Overview:
3098 ============================
3100 go - start application at address 'addr'
3101 run - run commands in an environment variable
3102 bootm - boot application image from memory
3103 bootp - boot image via network using BootP/TFTP protocol
3104 tftpboot- boot image via network using TFTP protocol
3105 and env variables "ipaddr" and "serverip"
3106 (and eventually "gatewayip")
3107 rarpboot- boot image via network using RARP/TFTP protocol
3108 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3109 loads - load S-Record file over serial line
3110 loadb - load binary file over serial line (kermit mode)
3112 mm - memory modify (auto-incrementing)
3113 nm - memory modify (constant address)
3114 mw - memory write (fill)
3116 cmp - memory compare
3117 crc32 - checksum calculation
3118 i2c - I2C sub-system
3119 sspi - SPI utility commands
3120 base - print or set address offset
3121 printenv- print environment variables
3122 setenv - set environment variables
3123 saveenv - save environment variables to persistent storage
3124 protect - enable or disable FLASH write protection
3125 erase - erase FLASH memory
3126 flinfo - print FLASH memory information
3127 bdinfo - print Board Info structure
3128 iminfo - print header information for application image
3129 coninfo - print console devices and informations
3130 ide - IDE sub-system
3131 loop - infinite loop on address range
3132 loopw - infinite write loop on address range
3133 mtest - simple RAM test
3134 icache - enable or disable instruction cache
3135 dcache - enable or disable data cache
3136 reset - Perform RESET of the CPU
3137 echo - echo args to console
3138 version - print monitor version
3139 help - print online help
3140 ? - alias for 'help'
3143 Monitor Commands - Detailed Description:
3144 ========================================
3148 For now: just type "help <command>".
3151 Environment Variables:
3152 ======================
3154 U-Boot supports user configuration using Environment Variables which
3155 can be made persistent by saving to Flash memory.
3157 Environment Variables are set using "setenv", printed using
3158 "printenv", and saved to Flash using "saveenv". Using "setenv"
3159 without a value can be used to delete a variable from the
3160 environment. As long as you don't save the environment you are
3161 working with an in-memory copy. In case the Flash area containing the
3162 environment is erased by accident, a default environment is provided.
3164 Some configuration options can be set using Environment Variables.
3166 List of environment variables (most likely not complete):
3168 baudrate - see CONFIG_BAUDRATE
3170 bootdelay - see CONFIG_BOOTDELAY
3172 bootcmd - see CONFIG_BOOTCOMMAND
3174 bootargs - Boot arguments when booting an RTOS image
3176 bootfile - Name of the image to load with TFTP
3178 bootm_low - Memory range available for image processing in the bootm
3179 command can be restricted. This variable is given as
3180 a hexadecimal number and defines lowest address allowed
3181 for use by the bootm command. See also "bootm_size"
3182 environment variable. Address defined by "bootm_low" is
3183 also the base of the initial memory mapping for the Linux
3184 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
3186 bootm_size - Memory range available for image processing in the bootm
3187 command can be restricted. This variable is given as
3188 a hexadecimal number and defines the size of the region
3189 allowed for use by the bootm command. See also "bootm_low"
3190 environment variable.
3192 updatefile - Location of the software update file on a TFTP server, used
3193 by the automatic software update feature. Please refer to
3194 documentation in doc/README.update for more details.
3196 autoload - if set to "no" (any string beginning with 'n'),
3197 "bootp" will just load perform a lookup of the
3198 configuration from the BOOTP server, but not try to
3199 load any image using TFTP
3201 autostart - if set to "yes", an image loaded using the "bootp",
3202 "rarpboot", "tftpboot" or "diskboot" commands will
3203 be automatically started (by internally calling
3206 If set to "no", a standalone image passed to the
3207 "bootm" command will be copied to the load address
3208 (and eventually uncompressed), but NOT be started.
3209 This can be used to load and uncompress arbitrary
3212 i2cfast - (PPC405GP|PPC405EP only)
3213 if set to 'y' configures Linux I2C driver for fast
3214 mode (400kHZ). This environment variable is used in
3215 initialization code. So, for changes to be effective
3216 it must be saved and board must be reset.
3218 initrd_high - restrict positioning of initrd images:
3219 If this variable is not set, initrd images will be
3220 copied to the highest possible address in RAM; this
3221 is usually what you want since it allows for
3222 maximum initrd size. If for some reason you want to
3223 make sure that the initrd image is loaded below the
3224 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3225 variable to a value of "no" or "off" or "0".
3226 Alternatively, you can set it to a maximum upper
3227 address to use (U-Boot will still check that it
3228 does not overwrite the U-Boot stack and data).
3230 For instance, when you have a system with 16 MB
3231 RAM, and want to reserve 4 MB from use by Linux,
3232 you can do this by adding "mem=12M" to the value of
3233 the "bootargs" variable. However, now you must make
3234 sure that the initrd image is placed in the first
3235 12 MB as well - this can be done with
3237 setenv initrd_high 00c00000
3239 If you set initrd_high to 0xFFFFFFFF, this is an
3240 indication to U-Boot that all addresses are legal
3241 for the Linux kernel, including addresses in flash
3242 memory. In this case U-Boot will NOT COPY the
3243 ramdisk at all. This may be useful to reduce the
3244 boot time on your system, but requires that this
3245 feature is supported by your Linux kernel.
3247 ipaddr - IP address; needed for tftpboot command
3249 loadaddr - Default load address for commands like "bootp",
3250 "rarpboot", "tftpboot", "loadb" or "diskboot"
3252 loads_echo - see CONFIG_LOADS_ECHO
3254 serverip - TFTP server IP address; needed for tftpboot command
3256 bootretry - see CONFIG_BOOT_RETRY_TIME
3258 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3260 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3262 ethprime - When CONFIG_NET_MULTI is enabled controls which
3263 interface is used first.
3265 ethact - When CONFIG_NET_MULTI is enabled controls which
3266 interface is currently active. For example you
3267 can do the following
3269 => setenv ethact FEC
3270 => ping 192.168.0.1 # traffic sent on FEC
3271 => setenv ethact SCC
3272 => ping 10.0.0.1 # traffic sent on SCC
3274 ethrotate - When set to "no" U-Boot does not go through all
3275 available network interfaces.
3276 It just stays at the currently selected interface.
3278 netretry - When set to "no" each network operation will
3279 either succeed or fail without retrying.
3280 When set to "once" the network operation will
3281 fail when all the available network interfaces
3282 are tried once without success.
3283 Useful on scripts which control the retry operation
3286 npe_ucode - set load address for the NPE microcode
3288 tftpsrcport - If this is set, the value is used for TFTP's
3291 tftpdstport - If this is set, the value is used for TFTP's UDP
3292 destination port instead of the Well Know Port 69.
3294 tftpblocksize - Block size to use for TFTP transfers; if not set,
3295 we use the TFTP server's default block size
3297 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3298 seconds, minimum value is 1000 = 1 second). Defines
3299 when a packet is considered to be lost so it has to
3300 be retransmitted. The default is 5000 = 5 seconds.
3301 Lowering this value may make downloads succeed
3302 faster in networks with high packet loss rates or
3303 with unreliable TFTP servers.
3305 vlan - When set to a value < 4095 the traffic over
3306 Ethernet is encapsulated/received over 802.1q
3309 The following environment variables may be used and automatically
3310 updated by the network boot commands ("bootp" and "rarpboot"),
3311 depending the information provided by your boot server:
3313 bootfile - see above
3314 dnsip - IP address of your Domain Name Server
3315 dnsip2 - IP address of your secondary Domain Name Server
3316 gatewayip - IP address of the Gateway (Router) to use
3317 hostname - Target hostname
3319 netmask - Subnet Mask
3320 rootpath - Pathname of the root filesystem on the NFS server
3321 serverip - see above
3324 There are two special Environment Variables:
3326 serial# - contains hardware identification information such
3327 as type string and/or serial number
3328 ethaddr - Ethernet address
3330 These variables can be set only once (usually during manufacturing of
3331 the board). U-Boot refuses to delete or overwrite these variables
3332 once they have been set once.
3335 Further special Environment Variables:
3337 ver - Contains the U-Boot version string as printed
3338 with the "version" command. This variable is
3339 readonly (see CONFIG_VERSION_VARIABLE).
3342 Please note that changes to some configuration parameters may take
3343 only effect after the next boot (yes, that's just like Windoze :-).
3346 Command Line Parsing:
3347 =====================
3349 There are two different command line parsers available with U-Boot:
3350 the old "simple" one, and the much more powerful "hush" shell:
3352 Old, simple command line parser:
3353 --------------------------------
3355 - supports environment variables (through setenv / saveenv commands)
3356 - several commands on one line, separated by ';'
3357 - variable substitution using "... ${name} ..." syntax
3358 - special characters ('$', ';') can be escaped by prefixing with '\',
3360 setenv bootcmd bootm \${address}
3361 - You can also escape text by enclosing in single apostrophes, for example:
3362 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3367 - similar to Bourne shell, with control structures like
3368 if...then...else...fi, for...do...done; while...do...done,
3369 until...do...done, ...
3370 - supports environment ("global") variables (through setenv / saveenv
3371 commands) and local shell variables (through standard shell syntax
3372 "name=value"); only environment variables can be used with "run"
3378 (1) If a command line (or an environment variable executed by a "run"
3379 command) contains several commands separated by semicolon, and
3380 one of these commands fails, then the remaining commands will be
3383 (2) If you execute several variables with one call to run (i. e.
3384 calling run with a list of variables as arguments), any failing
3385 command will cause "run" to terminate, i. e. the remaining
3386 variables are not executed.
3388 Note for Redundant Ethernet Interfaces:
3389 =======================================
3391 Some boards come with redundant Ethernet interfaces; U-Boot supports
3392 such configurations and is capable of automatic selection of a
3393 "working" interface when needed. MAC assignment works as follows:
3395 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3396 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3397 "eth1addr" (=>eth1), "eth2addr", ...
3399 If the network interface stores some valid MAC address (for instance
3400 in SROM), this is used as default address if there is NO correspon-
3401 ding setting in the environment; if the corresponding environment
3402 variable is set, this overrides the settings in the card; that means:
3404 o If the SROM has a valid MAC address, and there is no address in the
3405 environment, the SROM's address is used.
3407 o If there is no valid address in the SROM, and a definition in the
3408 environment exists, then the value from the environment variable is
3411 o If both the SROM and the environment contain a MAC address, and
3412 both addresses are the same, this MAC address is used.
3414 o If both the SROM and the environment contain a MAC address, and the
3415 addresses differ, the value from the environment is used and a
3418 o If neither SROM nor the environment contain a MAC address, an error
3421 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3422 will be programmed into hardware as part of the initialization process. This
3423 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3424 The naming convention is as follows:
3425 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3430 U-Boot is capable of booting (and performing other auxiliary operations on)
3431 images in two formats:
3433 New uImage format (FIT)
3434 -----------------------
3436 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3437 to Flattened Device Tree). It allows the use of images with multiple
3438 components (several kernels, ramdisks, etc.), with contents protected by
3439 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3445 Old image format is based on binary files which can be basically anything,
3446 preceded by a special header; see the definitions in include/image.h for
3447 details; basically, the header defines the following image properties:
3449 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3450 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3451 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3452 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3454 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3455 IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3456 Currently supported: ARM, AVR32, Intel x86, MIPS, Nios II, PowerPC).
3457 * Compression Type (uncompressed, gzip, bzip2)
3463 The header is marked by a special Magic Number, and both the header
3464 and the data portions of the image are secured against corruption by
3471 Although U-Boot should support any OS or standalone application
3472 easily, the main focus has always been on Linux during the design of
3475 U-Boot includes many features that so far have been part of some
3476 special "boot loader" code within the Linux kernel. Also, any
3477 "initrd" images to be used are no longer part of one big Linux image;
3478 instead, kernel and "initrd" are separate images. This implementation
3479 serves several purposes:
3481 - the same features can be used for other OS or standalone
3482 applications (for instance: using compressed images to reduce the
3483 Flash memory footprint)
3485 - it becomes much easier to port new Linux kernel versions because
3486 lots of low-level, hardware dependent stuff are done by U-Boot
3488 - the same Linux kernel image can now be used with different "initrd"
3489 images; of course this also means that different kernel images can
3490 be run with the same "initrd". This makes testing easier (you don't
3491 have to build a new "zImage.initrd" Linux image when you just
3492 change a file in your "initrd"). Also, a field-upgrade of the
3493 software is easier now.
3499 Porting Linux to U-Boot based systems:
3500 ---------------------------------------
3502 U-Boot cannot save you from doing all the necessary modifications to
3503 configure the Linux device drivers for use with your target hardware
3504 (no, we don't intend to provide a full virtual machine interface to
3507 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3509 Just make sure your machine specific header file (for instance
3510 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3511 Information structure as we define in include/asm-<arch>/u-boot.h,
3512 and make sure that your definition of IMAP_ADDR uses the same value
3513 as your U-Boot configuration in CONFIG_SYS_IMMR.
3516 Configuring the Linux kernel:
3517 -----------------------------
3519 No specific requirements for U-Boot. Make sure you have some root
3520 device (initial ramdisk, NFS) for your target system.
3523 Building a Linux Image:
3524 -----------------------
3526 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3527 not used. If you use recent kernel source, a new build target
3528 "uImage" will exist which automatically builds an image usable by
3529 U-Boot. Most older kernels also have support for a "pImage" target,
3530 which was introduced for our predecessor project PPCBoot and uses a
3531 100% compatible format.
3540 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3541 encapsulate a compressed Linux kernel image with header information,
3542 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3544 * build a standard "vmlinux" kernel image (in ELF binary format):
3546 * convert the kernel into a raw binary image:
3548 ${CROSS_COMPILE}-objcopy -O binary \
3549 -R .note -R .comment \
3550 -S vmlinux linux.bin
3552 * compress the binary image:
3556 * package compressed binary image for U-Boot:
3558 mkimage -A ppc -O linux -T kernel -C gzip \
3559 -a 0 -e 0 -n "Linux Kernel Image" \
3560 -d linux.bin.gz uImage
3563 The "mkimage" tool can also be used to create ramdisk images for use
3564 with U-Boot, either separated from the Linux kernel image, or
3565 combined into one file. "mkimage" encapsulates the images with a 64
3566 byte header containing information about target architecture,
3567 operating system, image type, compression method, entry points, time
3568 stamp, CRC32 checksums, etc.
3570 "mkimage" can be called in two ways: to verify existing images and
3571 print the header information, or to build new images.
3573 In the first form (with "-l" option) mkimage lists the information
3574 contained in the header of an existing U-Boot image; this includes
3575 checksum verification:
3577 tools/mkimage -l image
3578 -l ==> list image header information
3580 The second form (with "-d" option) is used to build a U-Boot image
3581 from a "data file" which is used as image payload:
3583 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3584 -n name -d data_file image
3585 -A ==> set architecture to 'arch'
3586 -O ==> set operating system to 'os'
3587 -T ==> set image type to 'type'
3588 -C ==> set compression type 'comp'
3589 -a ==> set load address to 'addr' (hex)
3590 -e ==> set entry point to 'ep' (hex)
3591 -n ==> set image name to 'name'
3592 -d ==> use image data from 'datafile'
3594 Right now, all Linux kernels for PowerPC systems use the same load
3595 address (0x00000000), but the entry point address depends on the
3598 - 2.2.x kernels have the entry point at 0x0000000C,
3599 - 2.3.x and later kernels have the entry point at 0x00000000.
3601 So a typical call to build a U-Boot image would read:
3603 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3604 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3605 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3606 > examples/uImage.TQM850L
3607 Image Name: 2.4.4 kernel for TQM850L
3608 Created: Wed Jul 19 02:34:59 2000
3609 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3610 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3611 Load Address: 0x00000000
3612 Entry Point: 0x00000000
3614 To verify the contents of the image (or check for corruption):
3616 -> tools/mkimage -l examples/uImage.TQM850L
3617 Image Name: 2.4.4 kernel for TQM850L
3618 Created: Wed Jul 19 02:34:59 2000
3619 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3620 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3621 Load Address: 0x00000000
3622 Entry Point: 0x00000000
3624 NOTE: for embedded systems where boot time is critical you can trade
3625 speed for memory and install an UNCOMPRESSED image instead: this
3626 needs more space in Flash, but boots much faster since it does not
3627 need to be uncompressed:
3629 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3630 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3631 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3632 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3633 > examples/uImage.TQM850L-uncompressed
3634 Image Name: 2.4.4 kernel for TQM850L
3635 Created: Wed Jul 19 02:34:59 2000
3636 Image Type: PowerPC Linux Kernel Image (uncompressed)
3637 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3638 Load Address: 0x00000000
3639 Entry Point: 0x00000000
3642 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3643 when your kernel is intended to use an initial ramdisk:
3645 -> tools/mkimage -n 'Simple Ramdisk Image' \
3646 > -A ppc -O linux -T ramdisk -C gzip \
3647 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3648 Image Name: Simple Ramdisk Image
3649 Created: Wed Jan 12 14:01:50 2000
3650 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3651 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3652 Load Address: 0x00000000
3653 Entry Point: 0x00000000
3656 Installing a Linux Image:
3657 -------------------------
3659 To downloading a U-Boot image over the serial (console) interface,
3660 you must convert the image to S-Record format:
3662 objcopy -I binary -O srec examples/image examples/image.srec
3664 The 'objcopy' does not understand the information in the U-Boot
3665 image header, so the resulting S-Record file will be relative to
3666 address 0x00000000. To load it to a given address, you need to
3667 specify the target address as 'offset' parameter with the 'loads'
3670 Example: install the image to address 0x40100000 (which on the
3671 TQM8xxL is in the first Flash bank):
3673 => erase 40100000 401FFFFF
3679 ## Ready for S-Record download ...
3680 ~>examples/image.srec
3681 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3683 15989 15990 15991 15992
3684 [file transfer complete]
3686 ## Start Addr = 0x00000000
3689 You can check the success of the download using the 'iminfo' command;
3690 this includes a checksum verification so you can be sure no data
3691 corruption happened:
3695 ## Checking Image at 40100000 ...
3696 Image Name: 2.2.13 for initrd on TQM850L
3697 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3698 Data Size: 335725 Bytes = 327 kB = 0 MB
3699 Load Address: 00000000
3700 Entry Point: 0000000c
3701 Verifying Checksum ... OK
3707 The "bootm" command is used to boot an application that is stored in
3708 memory (RAM or Flash). In case of a Linux kernel image, the contents
3709 of the "bootargs" environment variable is passed to the kernel as
3710 parameters. You can check and modify this variable using the
3711 "printenv" and "setenv" commands:
3714 => printenv bootargs
3715 bootargs=root=/dev/ram
3717 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3719 => printenv bootargs
3720 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3723 ## Booting Linux kernel at 40020000 ...
3724 Image Name: 2.2.13 for NFS on TQM850L
3725 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3726 Data Size: 381681 Bytes = 372 kB = 0 MB
3727 Load Address: 00000000
3728 Entry Point: 0000000c
3729 Verifying Checksum ... OK
3730 Uncompressing Kernel Image ... OK
3731 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
3732 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3733 time_init: decrementer frequency = 187500000/60
3734 Calibrating delay loop... 49.77 BogoMIPS
3735 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3738 If you want to boot a Linux kernel with initial RAM disk, you pass
3739 the memory addresses of both the kernel and the initrd image (PPBCOOT
3740 format!) to the "bootm" command:
3742 => imi 40100000 40200000
3744 ## Checking Image at 40100000 ...
3745 Image Name: 2.2.13 for initrd on TQM850L
3746 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3747 Data Size: 335725 Bytes = 327 kB = 0 MB
3748 Load Address: 00000000
3749 Entry Point: 0000000c
3750 Verifying Checksum ... OK
3752 ## Checking Image at 40200000 ...
3753 Image Name: Simple Ramdisk Image
3754 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3755 Data Size: 566530 Bytes = 553 kB = 0 MB
3756 Load Address: 00000000
3757 Entry Point: 00000000
3758 Verifying Checksum ... OK
3760 => bootm 40100000 40200000
3761 ## Booting Linux kernel at 40100000 ...
3762 Image Name: 2.2.13 for initrd on TQM850L
3763 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3764 Data Size: 335725 Bytes = 327 kB = 0 MB
3765 Load Address: 00000000
3766 Entry Point: 0000000c
3767 Verifying Checksum ... OK
3768 Uncompressing Kernel Image ... OK
3769 ## Loading RAMDisk Image at 40200000 ...
3770 Image Name: Simple Ramdisk Image
3771 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3772 Data Size: 566530 Bytes = 553 kB = 0 MB
3773 Load Address: 00000000
3774 Entry Point: 00000000
3775 Verifying Checksum ... OK
3776 Loading Ramdisk ... OK
3777 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
3778 Boot arguments: root=/dev/ram
3779 time_init: decrementer frequency = 187500000/60
3780 Calibrating delay loop... 49.77 BogoMIPS
3782 RAMDISK: Compressed image found at block 0
3783 VFS: Mounted root (ext2 filesystem).
3787 Boot Linux and pass a flat device tree:
3790 First, U-Boot must be compiled with the appropriate defines. See the section
3791 titled "Linux Kernel Interface" above for a more in depth explanation. The
3792 following is an example of how to start a kernel and pass an updated
3798 oft=oftrees/mpc8540ads.dtb
3799 => tftp $oftaddr $oft
3800 Speed: 1000, full duplex
3802 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3803 Filename 'oftrees/mpc8540ads.dtb'.
3804 Load address: 0x300000
3807 Bytes transferred = 4106 (100a hex)
3808 => tftp $loadaddr $bootfile
3809 Speed: 1000, full duplex
3811 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3813 Load address: 0x200000
3814 Loading:############
3816 Bytes transferred = 1029407 (fb51f hex)
3821 => bootm $loadaddr - $oftaddr
3822 ## Booting image at 00200000 ...
3823 Image Name: Linux-2.6.17-dirty
3824 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3825 Data Size: 1029343 Bytes = 1005.2 kB
3826 Load Address: 00000000
3827 Entry Point: 00000000
3828 Verifying Checksum ... OK
3829 Uncompressing Kernel Image ... OK
3830 Booting using flat device tree at 0x300000
3831 Using MPC85xx ADS machine description
3832 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3836 More About U-Boot Image Types:
3837 ------------------------------
3839 U-Boot supports the following image types:
3841 "Standalone Programs" are directly runnable in the environment
3842 provided by U-Boot; it is expected that (if they behave
3843 well) you can continue to work in U-Boot after return from
3844 the Standalone Program.
3845 "OS Kernel Images" are usually images of some Embedded OS which
3846 will take over control completely. Usually these programs
3847 will install their own set of exception handlers, device
3848 drivers, set up the MMU, etc. - this means, that you cannot
3849 expect to re-enter U-Boot except by resetting the CPU.
3850 "RAMDisk Images" are more or less just data blocks, and their
3851 parameters (address, size) are passed to an OS kernel that is
3853 "Multi-File Images" contain several images, typically an OS
3854 (Linux) kernel image and one or more data images like
3855 RAMDisks. This construct is useful for instance when you want
3856 to boot over the network using BOOTP etc., where the boot
3857 server provides just a single image file, but you want to get
3858 for instance an OS kernel and a RAMDisk image.
3860 "Multi-File Images" start with a list of image sizes, each
3861 image size (in bytes) specified by an "uint32_t" in network
3862 byte order. This list is terminated by an "(uint32_t)0".
3863 Immediately after the terminating 0 follow the images, one by
3864 one, all aligned on "uint32_t" boundaries (size rounded up to
3865 a multiple of 4 bytes).
3867 "Firmware Images" are binary images containing firmware (like
3868 U-Boot or FPGA images) which usually will be programmed to
3871 "Script files" are command sequences that will be executed by
3872 U-Boot's command interpreter; this feature is especially
3873 useful when you configure U-Boot to use a real shell (hush)
3874 as command interpreter.
3880 One of the features of U-Boot is that you can dynamically load and
3881 run "standalone" applications, which can use some resources of
3882 U-Boot like console I/O functions or interrupt services.
3884 Two simple examples are included with the sources:
3889 'examples/hello_world.c' contains a small "Hello World" Demo
3890 application; it is automatically compiled when you build U-Boot.
3891 It's configured to run at address 0x00040004, so you can play with it
3895 ## Ready for S-Record download ...
3896 ~>examples/hello_world.srec
3897 1 2 3 4 5 6 7 8 9 10 11 ...
3898 [file transfer complete]
3900 ## Start Addr = 0x00040004
3902 => go 40004 Hello World! This is a test.
3903 ## Starting application at 0x00040004 ...
3914 Hit any key to exit ...
3916 ## Application terminated, rc = 0x0
3918 Another example, which demonstrates how to register a CPM interrupt
3919 handler with the U-Boot code, can be found in 'examples/timer.c'.
3920 Here, a CPM timer is set up to generate an interrupt every second.
3921 The interrupt service routine is trivial, just printing a '.'
3922 character, but this is just a demo program. The application can be
3923 controlled by the following keys:
3925 ? - print current values og the CPM Timer registers
3926 b - enable interrupts and start timer
3927 e - stop timer and disable interrupts
3928 q - quit application
3931 ## Ready for S-Record download ...
3932 ~>examples/timer.srec
3933 1 2 3 4 5 6 7 8 9 10 11 ...
3934 [file transfer complete]
3936 ## Start Addr = 0x00040004
3939 ## Starting application at 0x00040004 ...
3942 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3945 [q, b, e, ?] Set interval 1000000 us
3948 [q, b, e, ?] ........
3949 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3952 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3955 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3958 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3960 [q, b, e, ?] ...Stopping timer
3962 [q, b, e, ?] ## Application terminated, rc = 0x0
3968 Over time, many people have reported problems when trying to use the
3969 "minicom" terminal emulation program for serial download. I (wd)
3970 consider minicom to be broken, and recommend not to use it. Under
3971 Unix, I recommend to use C-Kermit for general purpose use (and
3972 especially for kermit binary protocol download ("loadb" command), and
3973 use "cu" for S-Record download ("loads" command).
3975 Nevertheless, if you absolutely want to use it try adding this
3976 configuration to your "File transfer protocols" section:
3978 Name Program Name U/D FullScr IO-Red. Multi
3979 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3980 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3986 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3987 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3989 Building requires a cross environment; it is known to work on
3990 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3991 need gmake since the Makefiles are not compatible with BSD make).
3992 Note that the cross-powerpc package does not install include files;
3993 attempting to build U-Boot will fail because <machine/ansi.h> is
3994 missing. This file has to be installed and patched manually:
3996 # cd /usr/pkg/cross/powerpc-netbsd/include
3998 # ln -s powerpc machine
3999 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4000 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4002 Native builds *don't* work due to incompatibilities between native
4003 and U-Boot include files.
4005 Booting assumes that (the first part of) the image booted is a
4006 stage-2 loader which in turn loads and then invokes the kernel
4007 proper. Loader sources will eventually appear in the NetBSD source
4008 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4009 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4012 Implementation Internals:
4013 =========================
4015 The following is not intended to be a complete description of every
4016 implementation detail. However, it should help to understand the
4017 inner workings of U-Boot and make it easier to port it to custom
4021 Initial Stack, Global Data:
4022 ---------------------------
4024 The implementation of U-Boot is complicated by the fact that U-Boot
4025 starts running out of ROM (flash memory), usually without access to
4026 system RAM (because the memory controller is not initialized yet).
4027 This means that we don't have writable Data or BSS segments, and BSS
4028 is not initialized as zero. To be able to get a C environment working
4029 at all, we have to allocate at least a minimal stack. Implementation
4030 options for this are defined and restricted by the CPU used: Some CPU
4031 models provide on-chip memory (like the IMMR area on MPC8xx and
4032 MPC826x processors), on others (parts of) the data cache can be
4033 locked as (mis-) used as memory, etc.
4035 Chris Hallinan posted a good summary of these issues to the
4036 U-Boot mailing list:
4038 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4039 From: "Chris Hallinan" <clh@net1plus.com>
4040 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4043 Correct me if I'm wrong, folks, but the way I understand it
4044 is this: Using DCACHE as initial RAM for Stack, etc, does not
4045 require any physical RAM backing up the cache. The cleverness
4046 is that the cache is being used as a temporary supply of
4047 necessary storage before the SDRAM controller is setup. It's
4048 beyond the scope of this list to explain the details, but you
4049 can see how this works by studying the cache architecture and
4050 operation in the architecture and processor-specific manuals.
4052 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4053 is another option for the system designer to use as an
4054 initial stack/RAM area prior to SDRAM being available. Either
4055 option should work for you. Using CS 4 should be fine if your
4056 board designers haven't used it for something that would
4057 cause you grief during the initial boot! It is frequently not
4060 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4061 with your processor/board/system design. The default value
4062 you will find in any recent u-boot distribution in
4063 walnut.h should work for you. I'd set it to a value larger
4064 than your SDRAM module. If you have a 64MB SDRAM module, set
4065 it above 400_0000. Just make sure your board has no resources
4066 that are supposed to respond to that address! That code in
4067 start.S has been around a while and should work as is when
4068 you get the config right.
4073 It is essential to remember this, since it has some impact on the C
4074 code for the initialization procedures:
4076 * Initialized global data (data segment) is read-only. Do not attempt
4079 * Do not use any uninitialized global data (or implicitely initialized
4080 as zero data - BSS segment) at all - this is undefined, initiali-
4081 zation is performed later (when relocating to RAM).
4083 * Stack space is very limited. Avoid big data buffers or things like
4086 Having only the stack as writable memory limits means we cannot use
4087 normal global data to share information beween the code. But it
4088 turned out that the implementation of U-Boot can be greatly
4089 simplified by making a global data structure (gd_t) available to all
4090 functions. We could pass a pointer to this data as argument to _all_
4091 functions, but this would bloat the code. Instead we use a feature of
4092 the GCC compiler (Global Register Variables) to share the data: we
4093 place a pointer (gd) to the global data into a register which we
4094 reserve for this purpose.
4096 When choosing a register for such a purpose we are restricted by the
4097 relevant (E)ABI specifications for the current architecture, and by
4098 GCC's implementation.
4100 For PowerPC, the following registers have specific use:
4102 R2: reserved for system use
4103 R3-R4: parameter passing and return values
4104 R5-R10: parameter passing
4105 R13: small data area pointer
4109 (U-Boot also uses R12 as internal GOT pointer. r12
4110 is a volatile register so r12 needs to be reset when
4111 going back and forth between asm and C)
4113 ==> U-Boot will use R2 to hold a pointer to the global data
4115 Note: on PPC, we could use a static initializer (since the
4116 address of the global data structure is known at compile time),
4117 but it turned out that reserving a register results in somewhat
4118 smaller code - although the code savings are not that big (on
4119 average for all boards 752 bytes for the whole U-Boot image,
4120 624 text + 127 data).
4122 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4123 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4125 ==> U-Boot will use P3 to hold a pointer to the global data
4127 On ARM, the following registers are used:
4129 R0: function argument word/integer result
4130 R1-R3: function argument word
4132 R10: stack limit (used only if stack checking if enabled)
4133 R11: argument (frame) pointer
4134 R12: temporary workspace
4137 R15: program counter
4139 ==> U-Boot will use R8 to hold a pointer to the global data
4141 On Nios II, the ABI is documented here:
4142 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4144 ==> U-Boot will use gp to hold a pointer to the global data
4146 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4147 to access small data sections, so gp is free.
4149 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4150 or current versions of GCC may "optimize" the code too much.
4155 U-Boot runs in system state and uses physical addresses, i.e. the
4156 MMU is not used either for address mapping nor for memory protection.
4158 The available memory is mapped to fixed addresses using the memory
4159 controller. In this process, a contiguous block is formed for each
4160 memory type (Flash, SDRAM, SRAM), even when it consists of several
4161 physical memory banks.
4163 U-Boot is installed in the first 128 kB of the first Flash bank (on
4164 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4165 booting and sizing and initializing DRAM, the code relocates itself
4166 to the upper end of DRAM. Immediately below the U-Boot code some
4167 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4168 configuration setting]. Below that, a structure with global Board
4169 Info data is placed, followed by the stack (growing downward).
4171 Additionally, some exception handler code is copied to the low 8 kB
4172 of DRAM (0x00000000 ... 0x00001FFF).
4174 So a typical memory configuration with 16 MB of DRAM could look like
4177 0x0000 0000 Exception Vector code
4180 0x0000 2000 Free for Application Use
4186 0x00FB FF20 Monitor Stack (Growing downward)
4187 0x00FB FFAC Board Info Data and permanent copy of global data
4188 0x00FC 0000 Malloc Arena
4191 0x00FE 0000 RAM Copy of Monitor Code
4192 ... eventually: LCD or video framebuffer
4193 ... eventually: pRAM (Protected RAM - unchanged by reset)
4194 0x00FF FFFF [End of RAM]
4197 System Initialization:
4198 ----------------------
4200 In the reset configuration, U-Boot starts at the reset entry point
4201 (on most PowerPC systems at address 0x00000100). Because of the reset
4202 configuration for CS0# this is a mirror of the onboard Flash memory.
4203 To be able to re-map memory U-Boot then jumps to its link address.
4204 To be able to implement the initialization code in C, a (small!)
4205 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4206 which provide such a feature like MPC8xx or MPC8260), or in a locked
4207 part of the data cache. After that, U-Boot initializes the CPU core,
4208 the caches and the SIU.
4210 Next, all (potentially) available memory banks are mapped using a
4211 preliminary mapping. For example, we put them on 512 MB boundaries
4212 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4213 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4214 programmed for SDRAM access. Using the temporary configuration, a
4215 simple memory test is run that determines the size of the SDRAM
4218 When there is more than one SDRAM bank, and the banks are of
4219 different size, the largest is mapped first. For equal size, the first
4220 bank (CS2#) is mapped first. The first mapping is always for address
4221 0x00000000, with any additional banks following immediately to create
4222 contiguous memory starting from 0.
4224 Then, the monitor installs itself at the upper end of the SDRAM area
4225 and allocates memory for use by malloc() and for the global Board
4226 Info data; also, the exception vector code is copied to the low RAM
4227 pages, and the final stack is set up.
4229 Only after this relocation will you have a "normal" C environment;
4230 until that you are restricted in several ways, mostly because you are
4231 running from ROM, and because the code will have to be relocated to a
4235 U-Boot Porting Guide:
4236 ----------------------
4238 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4242 int main(int argc, char *argv[])
4244 sighandler_t no_more_time;
4246 signal(SIGALRM, no_more_time);
4247 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4249 if (available_money > available_manpower) {
4250 Pay consultant to port U-Boot;
4254 Download latest U-Boot source;
4256 Subscribe to u-boot mailing list;
4259 email("Hi, I am new to U-Boot, how do I get started?");
4262 Read the README file in the top level directory;
4263 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4264 Read applicable doc/*.README;
4265 Read the source, Luke;
4266 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4269 if (available_money > toLocalCurrency ($2500))
4272 Add a lot of aggravation and time;
4274 if (a similar board exists) { /* hopefully... */
4275 cp -a board/<similar> board/<myboard>
4276 cp include/configs/<similar>.h include/configs/<myboard>.h
4278 Create your own board support subdirectory;
4279 Create your own board include/configs/<myboard>.h file;
4281 Edit new board/<myboard> files
4282 Edit new include/configs/<myboard>.h
4287 Add / modify source code;
4291 email("Hi, I am having problems...");
4293 Send patch file to the U-Boot email list;
4294 if (reasonable critiques)
4295 Incorporate improvements from email list code review;
4297 Defend code as written;
4303 void no_more_time (int sig)
4312 All contributions to U-Boot should conform to the Linux kernel
4313 coding style; see the file "Documentation/CodingStyle" and the script
4314 "scripts/Lindent" in your Linux kernel source directory. In sources
4315 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4316 spaces before parameters to function calls) is actually used.
4318 Source files originating from a different project (for example the
4319 MTD subsystem) are generally exempt from these guidelines and are not
4320 reformated to ease subsequent migration to newer versions of those
4323 Please note that U-Boot is implemented in C (and to some small parts in
4324 Assembler); no C++ is used, so please do not use C++ style comments (//)
4327 Please also stick to the following formatting rules:
4328 - remove any trailing white space
4329 - use TAB characters for indentation, not spaces
4330 - make sure NOT to use DOS '\r\n' line feeds
4331 - do not add more than 2 empty lines to source files
4332 - do not add trailing empty lines to source files
4334 Submissions which do not conform to the standards may be returned
4335 with a request to reformat the changes.
4341 Since the number of patches for U-Boot is growing, we need to
4342 establish some rules. Submissions which do not conform to these rules
4343 may be rejected, even when they contain important and valuable stuff.
4345 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4347 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4348 see http://lists.denx.de/mailman/listinfo/u-boot
4350 When you send a patch, please include the following information with
4353 * For bug fixes: a description of the bug and how your patch fixes
4354 this bug. Please try to include a way of demonstrating that the
4355 patch actually fixes something.
4357 * For new features: a description of the feature and your
4360 * A CHANGELOG entry as plaintext (separate from the patch)
4362 * For major contributions, your entry to the CREDITS file
4364 * When you add support for a new board, don't forget to add this
4365 board to the MAKEALL script, too.
4367 * If your patch adds new configuration options, don't forget to
4368 document these in the README file.
4370 * The patch itself. If you are using git (which is *strongly*
4371 recommended) you can easily generate the patch using the
4372 "git-format-patch". If you then use "git-send-email" to send it to
4373 the U-Boot mailing list, you will avoid most of the common problems
4374 with some other mail clients.
4376 If you cannot use git, use "diff -purN OLD NEW". If your version of
4377 diff does not support these options, then get the latest version of
4380 The current directory when running this command shall be the parent
4381 directory of the U-Boot source tree (i. e. please make sure that
4382 your patch includes sufficient directory information for the
4385 We prefer patches as plain text. MIME attachments are discouraged,
4386 and compressed attachments must not be used.
4388 * If one logical set of modifications affects or creates several
4389 files, all these changes shall be submitted in a SINGLE patch file.
4391 * Changesets that contain different, unrelated modifications shall be
4392 submitted as SEPARATE patches, one patch per changeset.
4397 * Before sending the patch, run the MAKEALL script on your patched
4398 source tree and make sure that no errors or warnings are reported
4399 for any of the boards.
4401 * Keep your modifications to the necessary minimum: A patch
4402 containing several unrelated changes or arbitrary reformats will be
4403 returned with a request to re-formatting / split it.
4405 * If you modify existing code, make sure that your new code does not
4406 add to the memory footprint of the code ;-) Small is beautiful!
4407 When adding new features, these should compile conditionally only
4408 (using #ifdef), and the resulting code with the new feature
4409 disabled must not need more memory than the old code without your
4412 * Remember that there is a size limit of 100 kB per message on the
4413 u-boot mailing list. Bigger patches will be moderated. If they are
4414 reasonable and not too big, they will be acknowledged. But patches
4415 bigger than the size limit should be avoided.