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 - MPC824X Family Member (if CONFIG_MPC824X is defined)
323 Define exactly one of
324 CONFIG_MPC8240, CONFIG_MPC8245
326 - 8xx CPU Options: (if using an MPC8xx CPU)
327 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
328 get_gclk_freq() cannot work
329 e.g. if there is no 32KHz
330 reference PIT/RTC clock
331 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
334 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
335 CONFIG_SYS_8xx_CPUCLK_MIN
336 CONFIG_SYS_8xx_CPUCLK_MAX
337 CONFIG_8xx_CPUCLK_DEFAULT
338 See doc/README.MPC866
340 CONFIG_SYS_MEASURE_CPUCLK
342 Define this to measure the actual CPU clock instead
343 of relying on the correctness of the configured
344 values. Mostly useful for board bringup to make sure
345 the PLL is locked at the intended frequency. Note
346 that this requires a (stable) reference clock (32 kHz
347 RTC clock or CONFIG_SYS_8XX_XIN)
349 CONFIG_SYS_DELAYED_ICACHE
351 Define this option if you want to enable the
352 ICache only when Code runs from RAM.
354 - Intel Monahans options:
355 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
357 Defines the Monahans run mode to oscillator
358 ratio. Valid values are 8, 16, 24, 31. The core
359 frequency is this value multiplied by 13 MHz.
361 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
363 Defines the Monahans turbo mode to oscillator
364 ratio. Valid values are 1 (default if undefined) and
365 2. The core frequency as calculated above is multiplied
368 - Linux Kernel Interface:
371 U-Boot stores all clock information in Hz
372 internally. For binary compatibility with older Linux
373 kernels (which expect the clocks passed in the
374 bd_info data to be in MHz) the environment variable
375 "clocks_in_mhz" can be defined so that U-Boot
376 converts clock data to MHZ before passing it to the
378 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
379 "clocks_in_mhz=1" is automatically included in the
382 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
384 When transferring memsize parameter to linux, some versions
385 expect it to be in bytes, others in MB.
386 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
390 New kernel versions are expecting firmware settings to be
391 passed using flattened device trees (based on open firmware
395 * New libfdt-based support
396 * Adds the "fdt" command
397 * The bootm command automatically updates the fdt
399 OF_CPU - The proper name of the cpus node (only required for
400 MPC512X and MPC5xxx based boards).
401 OF_SOC - The proper name of the soc node (only required for
402 MPC512X and MPC5xxx based boards).
403 OF_TBCLK - The timebase frequency.
404 OF_STDOUT_PATH - The path to the console device
406 boards with QUICC Engines require OF_QE to set UCC MAC
409 CONFIG_OF_BOARD_SETUP
411 Board code has addition modification that it wants to make
412 to the flat device tree before handing it off to the kernel
416 This define fills in the correct boot CPU in the boot
417 param header, the default value is zero if undefined.
421 U-Boot can detect if an IDE device is present or not.
422 If not, and this new config option is activated, U-Boot
423 removes the ATA node from the DTS before booting Linux,
424 so the Linux IDE driver does not probe the device and
425 crash. This is needed for buggy hardware (uc101) where
426 no pull down resistor is connected to the signal IDE5V_DD7.
428 - vxWorks boot parameters:
430 bootvx constructs a valid bootline using the following
431 environments variables: bootfile, ipaddr, serverip, hostname.
432 It loads the vxWorks image pointed bootfile.
434 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
435 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
436 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
437 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
439 CONFIG_SYS_VXWORKS_ADD_PARAMS
441 Add it at the end of the bootline. E.g "u=username pw=secret"
443 Note: If a "bootargs" environment is defined, it will overwride
444 the defaults discussed just above.
449 Define this if you want support for Amba PrimeCell PL010 UARTs.
453 Define this if you want support for Amba PrimeCell PL011 UARTs.
457 If you have Amba PrimeCell PL011 UARTs, set this variable to
458 the clock speed of the UARTs.
462 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
463 define this to a list of base addresses for each (supported)
464 port. See e.g. include/configs/versatile.h
468 Depending on board, define exactly one serial port
469 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
470 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
471 console by defining CONFIG_8xx_CONS_NONE
473 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
474 port routines must be defined elsewhere
475 (i.e. serial_init(), serial_getc(), ...)
478 Enables console device for a color framebuffer. Needs following
479 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
480 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
482 VIDEO_HW_RECTFILL graphic chip supports
485 VIDEO_HW_BITBLT graphic chip supports
486 bit-blit (cf. smiLynxEM)
487 VIDEO_VISIBLE_COLS visible pixel columns
489 VIDEO_VISIBLE_ROWS visible pixel rows
490 VIDEO_PIXEL_SIZE bytes per pixel
491 VIDEO_DATA_FORMAT graphic data format
492 (0-5, cf. cfb_console.c)
493 VIDEO_FB_ADRS framebuffer address
494 VIDEO_KBD_INIT_FCT keyboard int fct
495 (i.e. i8042_kbd_init())
496 VIDEO_TSTC_FCT test char fct
498 VIDEO_GETC_FCT get char fct
500 CONFIG_CONSOLE_CURSOR cursor drawing on/off
501 (requires blink timer
503 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
504 CONFIG_CONSOLE_TIME display time/date info in
506 (requires CONFIG_CMD_DATE)
507 CONFIG_VIDEO_LOGO display Linux logo in
509 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
510 linux_logo.h for logo.
511 Requires CONFIG_VIDEO_LOGO
512 CONFIG_CONSOLE_EXTRA_INFO
513 additional board info beside
516 When CONFIG_CFB_CONSOLE is defined, video console is
517 default i/o. Serial console can be forced with
518 environment 'console=serial'.
520 When CONFIG_SILENT_CONSOLE is defined, all console
521 messages (by U-Boot and Linux!) can be silenced with
522 the "silent" environment variable. See
523 doc/README.silent for more information.
526 CONFIG_BAUDRATE - in bps
527 Select one of the baudrates listed in
528 CONFIG_SYS_BAUDRATE_TABLE, see below.
529 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
531 - Console Rx buffer length
532 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
533 the maximum receive buffer length for the SMC.
534 This option is actual only for 82xx and 8xx possible.
535 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
536 must be defined, to setup the maximum idle timeout for
539 - Boot Delay: CONFIG_BOOTDELAY - in seconds
540 Delay before automatically booting the default image;
541 set to -1 to disable autoboot.
543 See doc/README.autoboot for these options that
544 work with CONFIG_BOOTDELAY. None are required.
545 CONFIG_BOOT_RETRY_TIME
546 CONFIG_BOOT_RETRY_MIN
547 CONFIG_AUTOBOOT_KEYED
548 CONFIG_AUTOBOOT_PROMPT
549 CONFIG_AUTOBOOT_DELAY_STR
550 CONFIG_AUTOBOOT_STOP_STR
551 CONFIG_AUTOBOOT_DELAY_STR2
552 CONFIG_AUTOBOOT_STOP_STR2
553 CONFIG_ZERO_BOOTDELAY_CHECK
554 CONFIG_RESET_TO_RETRY
558 Only needed when CONFIG_BOOTDELAY is enabled;
559 define a command string that is automatically executed
560 when no character is read on the console interface
561 within "Boot Delay" after reset.
564 This can be used to pass arguments to the bootm
565 command. The value of CONFIG_BOOTARGS goes into the
566 environment value "bootargs".
568 CONFIG_RAMBOOT and CONFIG_NFSBOOT
569 The value of these goes into the environment as
570 "ramboot" and "nfsboot" respectively, and can be used
571 as a convenience, when switching between booting from
577 When this option is #defined, the existence of the
578 environment variable "preboot" will be checked
579 immediately before starting the CONFIG_BOOTDELAY
580 countdown and/or running the auto-boot command resp.
581 entering interactive mode.
583 This feature is especially useful when "preboot" is
584 automatically generated or modified. For an example
585 see the LWMON board specific code: here "preboot" is
586 modified when the user holds down a certain
587 combination of keys on the (special) keyboard when
590 - Serial Download Echo Mode:
592 If defined to 1, all characters received during a
593 serial download (using the "loads" command) are
594 echoed back. This might be needed by some terminal
595 emulations (like "cu"), but may as well just take
596 time on others. This setting #define's the initial
597 value of the "loads_echo" environment variable.
599 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
601 Select one of the baudrates listed in
602 CONFIG_SYS_BAUDRATE_TABLE, see below.
605 Monitor commands can be included or excluded
606 from the build by using the #include files
607 "config_cmd_all.h" and #undef'ing unwanted
608 commands, or using "config_cmd_default.h"
609 and augmenting with additional #define's
612 The default command configuration includes all commands
613 except those marked below with a "*".
615 CONFIG_CMD_ASKENV * ask for env variable
616 CONFIG_CMD_BDI bdinfo
617 CONFIG_CMD_BEDBUG * Include BedBug Debugger
618 CONFIG_CMD_BMP * BMP support
619 CONFIG_CMD_BSP * Board specific commands
620 CONFIG_CMD_BOOTD bootd
621 CONFIG_CMD_CACHE * icache, dcache
622 CONFIG_CMD_CONSOLE coninfo
623 CONFIG_CMD_DATE * support for RTC, date/time...
624 CONFIG_CMD_DHCP * DHCP support
625 CONFIG_CMD_DIAG * Diagnostics
626 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
627 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
628 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
629 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
630 CONFIG_CMD_DTT * Digital Therm and Thermostat
631 CONFIG_CMD_ECHO echo arguments
632 CONFIG_CMD_EDITENV edit env variable
633 CONFIG_CMD_EEPROM * EEPROM read/write support
634 CONFIG_CMD_ELF * bootelf, bootvx
635 CONFIG_CMD_SAVEENV saveenv
636 CONFIG_CMD_FDC * Floppy Disk Support
637 CONFIG_CMD_FAT * FAT partition support
638 CONFIG_CMD_FDOS * Dos diskette Support
639 CONFIG_CMD_FLASH flinfo, erase, protect
640 CONFIG_CMD_FPGA FPGA device initialization support
641 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
642 CONFIG_CMD_I2C * I2C serial bus support
643 CONFIG_CMD_IDE * IDE harddisk support
644 CONFIG_CMD_IMI iminfo
645 CONFIG_CMD_IMLS List all found images
646 CONFIG_CMD_IMMAP * IMMR dump support
647 CONFIG_CMD_IRQ * irqinfo
648 CONFIG_CMD_ITEST Integer/string test of 2 values
649 CONFIG_CMD_JFFS2 * JFFS2 Support
650 CONFIG_CMD_KGDB * kgdb
651 CONFIG_CMD_LOADB loadb
652 CONFIG_CMD_LOADS loads
653 CONFIG_CMD_MD5SUM print md5 message digest
654 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
655 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
657 CONFIG_CMD_MISC Misc functions like sleep etc
658 CONFIG_CMD_MMC * MMC memory mapped support
659 CONFIG_CMD_MII * MII utility commands
660 CONFIG_CMD_MTDPARTS * MTD partition support
661 CONFIG_CMD_NAND * NAND support
662 CONFIG_CMD_NET bootp, tftpboot, rarpboot
663 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
664 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
665 CONFIG_CMD_PCI * pciinfo
666 CONFIG_CMD_PCMCIA * PCMCIA support
667 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
669 CONFIG_CMD_PORTIO * Port I/O
670 CONFIG_CMD_REGINFO * Register dump
671 CONFIG_CMD_RUN run command in env variable
672 CONFIG_CMD_SAVES * save S record dump
673 CONFIG_CMD_SCSI * SCSI Support
674 CONFIG_CMD_SDRAM * print SDRAM configuration information
675 (requires CONFIG_CMD_I2C)
676 CONFIG_CMD_SETGETDCR Support for DCR Register access
678 CONFIG_CMD_SHA1 print sha1 memory digest
679 (requires CONFIG_CMD_MEMORY)
680 CONFIG_CMD_SOURCE "source" command Support
681 CONFIG_CMD_SPI * SPI serial bus support
682 CONFIG_CMD_USB * USB support
683 CONFIG_CMD_VFD * VFD support (TRAB)
684 CONFIG_CMD_CDP * Cisco Discover Protocol support
685 CONFIG_CMD_FSL * Microblaze FSL support
688 EXAMPLE: If you want all functions except of network
689 support you can write:
691 #include "config_cmd_all.h"
692 #undef CONFIG_CMD_NET
695 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
697 Note: Don't enable the "icache" and "dcache" commands
698 (configuration option CONFIG_CMD_CACHE) unless you know
699 what you (and your U-Boot users) are doing. Data
700 cache cannot be enabled on systems like the 8xx or
701 8260 (where accesses to the IMMR region must be
702 uncached), and it cannot be disabled on all other
703 systems where we (mis-) use the data cache to hold an
704 initial stack and some data.
707 XXX - this list needs to get updated!
711 If this variable is defined, it enables watchdog
712 support. There must be support in the platform specific
713 code for a watchdog. For the 8xx and 8260 CPUs, the
714 SIU Watchdog feature is enabled in the SYPCR
718 CONFIG_VERSION_VARIABLE
719 If this variable is defined, an environment variable
720 named "ver" is created by U-Boot showing the U-Boot
721 version as printed by the "version" command.
722 This variable is readonly.
726 When CONFIG_CMD_DATE is selected, the type of the RTC
727 has to be selected, too. Define exactly one of the
730 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
731 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
732 CONFIG_RTC_MC13783 - use MC13783 RTC
733 CONFIG_RTC_MC146818 - use MC146818 RTC
734 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
735 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
736 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
737 CONFIG_RTC_DS164x - use Dallas DS164x RTC
738 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
739 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
740 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
742 Note that if the RTC uses I2C, then the I2C interface
743 must also be configured. See I2C Support, below.
746 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
747 CONFIG_PCA953X_INFO - enable pca953x info command
749 Note that if the GPIO device uses I2C, then the I2C interface
750 must also be configured. See I2C Support, below.
754 When CONFIG_TIMESTAMP is selected, the timestamp
755 (date and time) of an image is printed by image
756 commands like bootm or iminfo. This option is
757 automatically enabled when you select CONFIG_CMD_DATE .
760 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
761 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
763 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
764 CONFIG_CMD_SCSI) you must configure support for at
765 least one partition type as well.
768 CONFIG_IDE_RESET_ROUTINE - this is defined in several
769 board configurations files but used nowhere!
771 CONFIG_IDE_RESET - is this is defined, IDE Reset will
772 be performed by calling the function
773 ide_set_reset(int reset)
774 which has to be defined in a board specific file
779 Set this to enable ATAPI support.
784 Set this to enable support for disks larger than 137GB
785 Also look at CONFIG_SYS_64BIT_LBA.
786 Whithout these , LBA48 support uses 32bit variables and will 'only'
787 support disks up to 2.1TB.
789 CONFIG_SYS_64BIT_LBA:
790 When enabled, makes the IDE subsystem use 64bit sector addresses.
794 At the moment only there is only support for the
795 SYM53C8XX SCSI controller; define
796 CONFIG_SCSI_SYM53C8XX to enable it.
798 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
799 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
800 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
801 maximum numbers of LUNs, SCSI ID's and target
803 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
805 - NETWORK Support (PCI):
807 Support for Intel 8254x gigabit chips.
809 CONFIG_E1000_FALLBACK_MAC
810 default MAC for empty EEPROM after production.
813 Support for Intel 82557/82559/82559ER chips.
814 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
815 write routine for first time initialisation.
818 Support for Digital 2114x chips.
819 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
820 modem chip initialisation (KS8761/QS6611).
823 Support for National dp83815 chips.
826 Support for National dp8382[01] gigabit chips.
828 - NETWORK Support (other):
830 CONFIG_DRIVER_AT91EMAC
831 Support for AT91RM9200 EMAC.
834 Define this to use reduced MII inteface
836 CONFIG_DRIVER_AT91EMAC_QUIET
837 If this defined, the driver is quiet.
838 The driver doen't show link status messages.
840 CONFIG_DRIVER_LAN91C96
841 Support for SMSC's LAN91C96 chips.
844 Define this to hold the physical address
845 of the LAN91C96's I/O space
847 CONFIG_LAN91C96_USE_32_BIT
848 Define this to enable 32 bit addressing
850 CONFIG_DRIVER_SMC91111
851 Support for SMSC's LAN91C111 chip
854 Define this to hold the physical address
855 of the device (I/O space)
857 CONFIG_SMC_USE_32_BIT
858 Define this if data bus is 32 bits
860 CONFIG_SMC_USE_IOFUNCS
861 Define this to use i/o functions instead of macros
862 (some hardware wont work with macros)
865 Support for SMSC's LAN911x and LAN921x chips
868 Define this to hold the physical address
869 of the device (I/O space)
871 CONFIG_SMC911X_32_BIT
872 Define this if data bus is 32 bits
874 CONFIG_SMC911X_16_BIT
875 Define this if data bus is 16 bits. If your processor
876 automatically converts one 32 bit word to two 16 bit
877 words you may also try CONFIG_SMC911X_32_BIT.
880 At the moment only the UHCI host controller is
881 supported (PIP405, MIP405, MPC5200); define
882 CONFIG_USB_UHCI to enable it.
883 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
884 and define CONFIG_USB_STORAGE to enable the USB
887 Supported are USB Keyboards and USB Floppy drives
889 MPC5200 USB requires additional defines:
891 for 528 MHz Clock: 0x0001bbbb
895 for differential drivers: 0x00001000
896 for single ended drivers: 0x00005000
897 for differential drivers on PSC3: 0x00000100
898 for single ended drivers on PSC3: 0x00004100
899 CONFIG_SYS_USB_EVENT_POLL
900 May be defined to allow interrupt polling
901 instead of using asynchronous interrupts
904 Define the below if you wish to use the USB console.
905 Once firmware is rebuilt from a serial console issue the
906 command "setenv stdin usbtty; setenv stdout usbtty" and
907 attach your USB cable. The Unix command "dmesg" should print
908 it has found a new device. The environment variable usbtty
909 can be set to gserial or cdc_acm to enable your device to
910 appear to a USB host as a Linux gserial device or a
911 Common Device Class Abstract Control Model serial device.
912 If you select usbtty = gserial you should be able to enumerate
914 # modprobe usbserial vendor=0xVendorID product=0xProductID
915 else if using cdc_acm, simply setting the environment
916 variable usbtty to be cdc_acm should suffice. The following
917 might be defined in YourBoardName.h
920 Define this to build a UDC device
923 Define this to have a tty type of device available to
924 talk to the UDC device
926 CONFIG_SYS_CONSOLE_IS_IN_ENV
927 Define this if you want stdin, stdout &/or stderr to
931 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
932 Derive USB clock from external clock "blah"
933 - CONFIG_SYS_USB_EXTC_CLK 0x02
935 CONFIG_SYS_USB_BRG_CLK 0xBLAH
936 Derive USB clock from brgclk
937 - CONFIG_SYS_USB_BRG_CLK 0x04
939 If you have a USB-IF assigned VendorID then you may wish to
940 define your own vendor specific values either in BoardName.h
941 or directly in usbd_vendor_info.h. If you don't define
942 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
943 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
944 should pretend to be a Linux device to it's target host.
946 CONFIG_USBD_MANUFACTURER
947 Define this string as the name of your company for
948 - CONFIG_USBD_MANUFACTURER "my company"
950 CONFIG_USBD_PRODUCT_NAME
951 Define this string as the name of your product
952 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
955 Define this as your assigned Vendor ID from the USB
956 Implementors Forum. This *must* be a genuine Vendor ID
957 to avoid polluting the USB namespace.
958 - CONFIG_USBD_VENDORID 0xFFFF
960 CONFIG_USBD_PRODUCTID
961 Define this as the unique Product ID
963 - CONFIG_USBD_PRODUCTID 0xFFFF
967 The MMC controller on the Intel PXA is supported. To
968 enable this define CONFIG_MMC. The MMC can be
969 accessed from the boot prompt by mapping the device
970 to physical memory similar to flash. Command line is
971 enabled with CONFIG_CMD_MMC. The MMC driver also works with
972 the FAT fs. This is enabled with CONFIG_CMD_FAT.
974 - Journaling Flash filesystem support:
975 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
976 CONFIG_JFFS2_NAND_DEV
977 Define these for a default partition on a NAND device
979 CONFIG_SYS_JFFS2_FIRST_SECTOR,
980 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
981 Define these for a default partition on a NOR device
983 CONFIG_SYS_JFFS_CUSTOM_PART
984 Define this to create an own partition. You have to provide a
985 function struct part_info* jffs2_part_info(int part_num)
987 If you define only one JFFS2 partition you may also want to
988 #define CONFIG_SYS_JFFS_SINGLE_PART 1
989 to disable the command chpart. This is the default when you
990 have not defined a custom partition
995 Define this to enable standard (PC-Style) keyboard
999 Standard PC keyboard driver with US (is default) and
1000 GERMAN key layout (switch via environment 'keymap=de') support.
1001 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1002 for cfb_console. Supports cursor blinking.
1007 Define this to enable video support (for output to
1010 CONFIG_VIDEO_CT69000
1012 Enable Chips & Technologies 69000 Video chip
1014 CONFIG_VIDEO_SMI_LYNXEM
1015 Enable Silicon Motion SMI 712/710/810 Video chip. The
1016 video output is selected via environment 'videoout'
1017 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1020 For the CT69000 and SMI_LYNXEM drivers, videomode is
1021 selected via environment 'videomode'. Two different ways
1023 - "videomode=num" 'num' is a standard LiLo mode numbers.
1024 Following standard modes are supported (* is default):
1026 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1027 -------------+---------------------------------------------
1028 8 bits | 0x301* 0x303 0x305 0x161 0x307
1029 15 bits | 0x310 0x313 0x316 0x162 0x319
1030 16 bits | 0x311 0x314 0x317 0x163 0x31A
1031 24 bits | 0x312 0x315 0x318 ? 0x31B
1032 -------------+---------------------------------------------
1033 (i.e. setenv videomode 317; saveenv; reset;)
1035 - "videomode=bootargs" all the video parameters are parsed
1036 from the bootargs. (See drivers/video/videomodes.c)
1039 CONFIG_VIDEO_SED13806
1040 Enable Epson SED13806 driver. This driver supports 8bpp
1041 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1042 or CONFIG_VIDEO_SED13806_16BPP
1047 Define this to enable a custom keyboard support.
1048 This simply calls drv_keyboard_init() which must be
1049 defined in your board-specific files.
1050 The only board using this so far is RBC823.
1052 - LCD Support: CONFIG_LCD
1054 Define this to enable LCD support (for output to LCD
1055 display); also select one of the supported displays
1056 by defining one of these:
1060 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1062 CONFIG_NEC_NL6448AC33:
1064 NEC NL6448AC33-18. Active, color, single scan.
1066 CONFIG_NEC_NL6448BC20
1068 NEC NL6448BC20-08. 6.5", 640x480.
1069 Active, color, single scan.
1071 CONFIG_NEC_NL6448BC33_54
1073 NEC NL6448BC33-54. 10.4", 640x480.
1074 Active, color, single scan.
1078 Sharp 320x240. Active, color, single scan.
1079 It isn't 16x9, and I am not sure what it is.
1081 CONFIG_SHARP_LQ64D341
1083 Sharp LQ64D341 display, 640x480.
1084 Active, color, single scan.
1088 HLD1045 display, 640x480.
1089 Active, color, single scan.
1093 Optrex CBL50840-2 NF-FW 99 22 M5
1095 Hitachi LMG6912RPFC-00T
1099 320x240. Black & white.
1101 Normally display is black on white background; define
1102 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1104 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1106 If this option is set, the environment is checked for
1107 a variable "splashimage". If found, the usual display
1108 of logo, copyright and system information on the LCD
1109 is suppressed and the BMP image at the address
1110 specified in "splashimage" is loaded instead. The
1111 console is redirected to the "nulldev", too. This
1112 allows for a "silent" boot where a splash screen is
1113 loaded very quickly after power-on.
1115 CONFIG_SPLASH_SCREEN_ALIGN
1117 If this option is set the splash image can be freely positioned
1118 on the screen. Environment variable "splashpos" specifies the
1119 position as "x,y". If a positive number is given it is used as
1120 number of pixel from left/top. If a negative number is given it
1121 is used as number of pixel from right/bottom. You can also
1122 specify 'm' for centering the image.
1125 setenv splashpos m,m
1126 => image at center of screen
1128 setenv splashpos 30,20
1129 => image at x = 30 and y = 20
1131 setenv splashpos -10,m
1132 => vertically centered image
1133 at x = dspWidth - bmpWidth - 9
1135 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1137 If this option is set, additionally to standard BMP
1138 images, gzipped BMP images can be displayed via the
1139 splashscreen support or the bmp command.
1141 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1143 If this option is set, 8-bit RLE compressed BMP images
1144 can be displayed via the splashscreen support or the
1147 - Compression support:
1150 If this option is set, support for bzip2 compressed
1151 images is included. If not, only uncompressed and gzip
1152 compressed images are supported.
1154 NOTE: the bzip2 algorithm requires a lot of RAM, so
1155 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1160 If this option is set, support for lzma compressed
1163 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1164 requires an amount of dynamic memory that is given by the
1167 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1169 Where lc and lp stand for, respectively, Literal context bits
1170 and Literal pos bits.
1172 This value is upper-bounded by 14MB in the worst case. Anyway,
1173 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1174 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1175 a very small buffer.
1177 Use the lzmainfo tool to determinate the lc and lp values and
1178 then calculate the amount of needed dynamic memory (ensuring
1179 the appropriate CONFIG_SYS_MALLOC_LEN value).
1184 The address of PHY on MII bus.
1186 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1188 The clock frequency of the MII bus
1192 If this option is set, support for speed/duplex
1193 detection of gigabit PHY is included.
1195 CONFIG_PHY_RESET_DELAY
1197 Some PHY like Intel LXT971A need extra delay after
1198 reset before any MII register access is possible.
1199 For such PHY, set this option to the usec delay
1200 required. (minimum 300usec for LXT971A)
1202 CONFIG_PHY_CMD_DELAY (ppc4xx)
1204 Some PHY like Intel LXT971A need extra delay after
1205 command issued before MII status register can be read
1215 Define a default value for Ethernet address to use
1216 for the respective Ethernet interface, in case this
1217 is not determined automatically.
1222 Define a default value for the IP address to use for
1223 the default Ethernet interface, in case this is not
1224 determined through e.g. bootp.
1226 - Server IP address:
1229 Defines a default value for the IP address of a TFTP
1230 server to contact when using the "tftboot" command.
1232 CONFIG_KEEP_SERVERADDR
1234 Keeps the server's MAC address, in the env 'serveraddr'
1235 for passing to bootargs (like Linux's netconsole option)
1237 - Multicast TFTP Mode:
1240 Defines whether you want to support multicast TFTP as per
1241 rfc-2090; for example to work with atftp. Lets lots of targets
1242 tftp down the same boot image concurrently. Note: the Ethernet
1243 driver in use must provide a function: mcast() to join/leave a
1246 CONFIG_BOOTP_RANDOM_DELAY
1247 - BOOTP Recovery Mode:
1248 CONFIG_BOOTP_RANDOM_DELAY
1250 If you have many targets in a network that try to
1251 boot using BOOTP, you may want to avoid that all
1252 systems send out BOOTP requests at precisely the same
1253 moment (which would happen for instance at recovery
1254 from a power failure, when all systems will try to
1255 boot, thus flooding the BOOTP server. Defining
1256 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1257 inserted before sending out BOOTP requests. The
1258 following delays are inserted then:
1260 1st BOOTP request: delay 0 ... 1 sec
1261 2nd BOOTP request: delay 0 ... 2 sec
1262 3rd BOOTP request: delay 0 ... 4 sec
1264 BOOTP requests: delay 0 ... 8 sec
1266 - DHCP Advanced Options:
1267 You can fine tune the DHCP functionality by defining
1268 CONFIG_BOOTP_* symbols:
1270 CONFIG_BOOTP_SUBNETMASK
1271 CONFIG_BOOTP_GATEWAY
1272 CONFIG_BOOTP_HOSTNAME
1273 CONFIG_BOOTP_NISDOMAIN
1274 CONFIG_BOOTP_BOOTPATH
1275 CONFIG_BOOTP_BOOTFILESIZE
1278 CONFIG_BOOTP_SEND_HOSTNAME
1279 CONFIG_BOOTP_NTPSERVER
1280 CONFIG_BOOTP_TIMEOFFSET
1281 CONFIG_BOOTP_VENDOREX
1283 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1284 environment variable, not the BOOTP server.
1286 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1287 serverip from a DHCP server, it is possible that more
1288 than one DNS serverip is offered to the client.
1289 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1290 serverip will be stored in the additional environment
1291 variable "dnsip2". The first DNS serverip is always
1292 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1295 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1296 to do a dynamic update of a DNS server. To do this, they
1297 need the hostname of the DHCP requester.
1298 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1299 of the "hostname" environment variable is passed as
1300 option 12 to the DHCP server.
1302 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1304 A 32bit value in microseconds for a delay between
1305 receiving a "DHCP Offer" and sending the "DHCP Request".
1306 This fixes a problem with certain DHCP servers that don't
1307 respond 100% of the time to a "DHCP request". E.g. On an
1308 AT91RM9200 processor running at 180MHz, this delay needed
1309 to be *at least* 15,000 usec before a Windows Server 2003
1310 DHCP server would reply 100% of the time. I recommend at
1311 least 50,000 usec to be safe. The alternative is to hope
1312 that one of the retries will be successful but note that
1313 the DHCP timeout and retry process takes a longer than
1317 CONFIG_CDP_DEVICE_ID
1319 The device id used in CDP trigger frames.
1321 CONFIG_CDP_DEVICE_ID_PREFIX
1323 A two character string which is prefixed to the MAC address
1328 A printf format string which contains the ascii name of
1329 the port. Normally is set to "eth%d" which sets
1330 eth0 for the first Ethernet, eth1 for the second etc.
1332 CONFIG_CDP_CAPABILITIES
1334 A 32bit integer which indicates the device capabilities;
1335 0x00000010 for a normal host which does not forwards.
1339 An ascii string containing the version of the software.
1343 An ascii string containing the name of the platform.
1347 A 32bit integer sent on the trigger.
1349 CONFIG_CDP_POWER_CONSUMPTION
1351 A 16bit integer containing the power consumption of the
1352 device in .1 of milliwatts.
1354 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1356 A byte containing the id of the VLAN.
1358 - Status LED: CONFIG_STATUS_LED
1360 Several configurations allow to display the current
1361 status using a LED. For instance, the LED will blink
1362 fast while running U-Boot code, stop blinking as
1363 soon as a reply to a BOOTP request was received, and
1364 start blinking slow once the Linux kernel is running
1365 (supported by a status LED driver in the Linux
1366 kernel). Defining CONFIG_STATUS_LED enables this
1369 - CAN Support: CONFIG_CAN_DRIVER
1371 Defining CONFIG_CAN_DRIVER enables CAN driver support
1372 on those systems that support this (optional)
1373 feature, like the TQM8xxL modules.
1375 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1377 These enable I2C serial bus commands. Defining either of
1378 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1379 include the appropriate I2C driver for the selected CPU.
1381 This will allow you to use i2c commands at the u-boot
1382 command line (as long as you set CONFIG_CMD_I2C in
1383 CONFIG_COMMANDS) and communicate with i2c based realtime
1384 clock chips. See common/cmd_i2c.c for a description of the
1385 command line interface.
1387 CONFIG_HARD_I2C selects a hardware I2C controller.
1389 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1390 bit-banging) driver instead of CPM or similar hardware
1393 There are several other quantities that must also be
1394 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1396 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1397 to be the frequency (in Hz) at which you wish your i2c bus
1398 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1399 the CPU's i2c node address).
1401 Now, the u-boot i2c code for the mpc8xx
1402 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1403 and so its address should therefore be cleared to 0 (See,
1404 eg, MPC823e User's Manual p.16-473). So, set
1405 CONFIG_SYS_I2C_SLAVE to 0.
1407 CONFIG_SYS_I2C_INIT_MPC5XXX
1409 When a board is reset during an i2c bus transfer
1410 chips might think that the current transfer is still
1411 in progress. Reset the slave devices by sending start
1412 commands until the slave device responds.
1414 That's all that's required for CONFIG_HARD_I2C.
1416 If you use the software i2c interface (CONFIG_SOFT_I2C)
1417 then the following macros need to be defined (examples are
1418 from include/configs/lwmon.h):
1422 (Optional). Any commands necessary to enable the I2C
1423 controller or configure ports.
1425 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1429 (Only for MPC8260 CPU). The I/O port to use (the code
1430 assumes both bits are on the same port). Valid values
1431 are 0..3 for ports A..D.
1435 The code necessary to make the I2C data line active
1436 (driven). If the data line is open collector, this
1439 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1443 The code necessary to make the I2C data line tri-stated
1444 (inactive). If the data line is open collector, this
1447 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1451 Code that returns TRUE if the I2C data line is high,
1454 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1458 If <bit> is TRUE, sets the I2C data line high. If it
1459 is FALSE, it clears it (low).
1461 eg: #define I2C_SDA(bit) \
1462 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1463 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1467 If <bit> is TRUE, sets the I2C clock line high. If it
1468 is FALSE, it clears it (low).
1470 eg: #define I2C_SCL(bit) \
1471 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1472 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1476 This delay is invoked four times per clock cycle so this
1477 controls the rate of data transfer. The data rate thus
1478 is 1 / (I2C_DELAY * 4). Often defined to be something
1481 #define I2C_DELAY udelay(2)
1483 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1485 If your arch supports the generic GPIO framework (asm/gpio.h),
1486 then you may alternatively define the two GPIOs that are to be
1487 used as SCL / SDA. Any of the previous I2C_xxx macros will
1488 have GPIO-based defaults assigned to them as appropriate.
1490 You should define these to the GPIO value as given directly to
1491 the generic GPIO functions.
1493 CONFIG_SYS_I2C_INIT_BOARD
1495 When a board is reset during an i2c bus transfer
1496 chips might think that the current transfer is still
1497 in progress. On some boards it is possible to access
1498 the i2c SCLK line directly, either by using the
1499 processor pin as a GPIO or by having a second pin
1500 connected to the bus. If this option is defined a
1501 custom i2c_init_board() routine in boards/xxx/board.c
1502 is run early in the boot sequence.
1504 CONFIG_SYS_I2C_BOARD_LATE_INIT
1506 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1507 defined a custom i2c_board_late_init() routine in
1508 boards/xxx/board.c is run AFTER the operations in i2c_init()
1509 is completed. This callpoint can be used to unreset i2c bus
1510 using CPU i2c controller register accesses for CPUs whose i2c
1511 controller provide such a method. It is called at the end of
1512 i2c_init() to allow i2c_init operations to setup the i2c bus
1513 controller on the CPU (e.g. setting bus speed & slave address).
1515 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1517 This option enables configuration of bi_iic_fast[] flags
1518 in u-boot bd_info structure based on u-boot environment
1519 variable "i2cfast". (see also i2cfast)
1521 CONFIG_I2C_MULTI_BUS
1523 This option allows the use of multiple I2C buses, each of which
1524 must have a controller. At any point in time, only one bus is
1525 active. To switch to a different bus, use the 'i2c dev' command.
1526 Note that bus numbering is zero-based.
1528 CONFIG_SYS_I2C_NOPROBES
1530 This option specifies a list of I2C devices that will be skipped
1531 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1532 is set, specify a list of bus-device pairs. Otherwise, specify
1533 a 1D array of device addresses
1536 #undef CONFIG_I2C_MULTI_BUS
1537 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1539 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1541 #define CONFIG_I2C_MULTI_BUS
1542 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1544 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1546 CONFIG_SYS_SPD_BUS_NUM
1548 If defined, then this indicates the I2C bus number for DDR SPD.
1549 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1551 CONFIG_SYS_RTC_BUS_NUM
1553 If defined, then this indicates the I2C bus number for the RTC.
1554 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1556 CONFIG_SYS_DTT_BUS_NUM
1558 If defined, then this indicates the I2C bus number for the DTT.
1559 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1561 CONFIG_SYS_I2C_DTT_ADDR:
1563 If defined, specifies the I2C address of the DTT device.
1564 If not defined, then U-Boot uses predefined value for
1565 specified DTT device.
1569 Define this option if you want to use Freescale's I2C driver in
1570 drivers/i2c/fsl_i2c.c.
1574 Define this option if you have I2C devices reached over 1 .. n
1575 I2C Muxes like the pca9544a. This option addes a new I2C
1576 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1577 new I2C Bus to the existing I2C Busses. If you select the
1578 new Bus with "i2c dev", u-bbot sends first the commandos for
1579 the muxes to activate this new "bus".
1581 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1585 Adding a new I2C Bus reached over 2 pca9544a muxes
1586 The First mux with address 70 and channel 6
1587 The Second mux with address 71 and channel 4
1589 => i2c bus pca9544a:70:6:pca9544a:71:4
1591 Use the "i2c bus" command without parameter, to get a list
1592 of I2C Busses with muxes:
1595 Busses reached over muxes:
1597 reached over Mux(es):
1600 reached over Mux(es):
1605 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1606 u-boot sends First the Commando to the mux@70 to enable
1607 channel 6, and then the Commando to the mux@71 to enable
1610 After that, you can use the "normal" i2c commands as
1611 usual, to communicate with your I2C devices behind
1614 This option is actually implemented for the bitbanging
1615 algorithm in common/soft_i2c.c and for the Hardware I2C
1616 Bus on the MPC8260. But it should be not so difficult
1617 to add this option to other architectures.
1619 CONFIG_SOFT_I2C_READ_REPEATED_START
1621 defining this will force the i2c_read() function in
1622 the soft_i2c driver to perform an I2C repeated start
1623 between writing the address pointer and reading the
1624 data. If this define is omitted the default behaviour
1625 of doing a stop-start sequence will be used. Most I2C
1626 devices can use either method, but some require one or
1629 - SPI Support: CONFIG_SPI
1631 Enables SPI driver (so far only tested with
1632 SPI EEPROM, also an instance works with Crystal A/D and
1633 D/As on the SACSng board)
1637 Enables extended (16-bit) SPI EEPROM addressing.
1638 (symmetrical to CONFIG_I2C_X)
1642 Enables a software (bit-bang) SPI driver rather than
1643 using hardware support. This is a general purpose
1644 driver that only requires three general I/O port pins
1645 (two outputs, one input) to function. If this is
1646 defined, the board configuration must define several
1647 SPI configuration items (port pins to use, etc). For
1648 an example, see include/configs/sacsng.h.
1652 Enables a hardware SPI driver for general-purpose reads
1653 and writes. As with CONFIG_SOFT_SPI, the board configuration
1654 must define a list of chip-select function pointers.
1655 Currently supported on some MPC8xxx processors. For an
1656 example, see include/configs/mpc8349emds.h.
1660 Enables the driver for the SPI controllers on i.MX and MXC
1661 SoCs. Currently only i.MX31 is supported.
1663 - FPGA Support: CONFIG_FPGA
1665 Enables FPGA subsystem.
1667 CONFIG_FPGA_<vendor>
1669 Enables support for specific chip vendors.
1672 CONFIG_FPGA_<family>
1674 Enables support for FPGA family.
1675 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1679 Specify the number of FPGA devices to support.
1681 CONFIG_SYS_FPGA_PROG_FEEDBACK
1683 Enable printing of hash marks during FPGA configuration.
1685 CONFIG_SYS_FPGA_CHECK_BUSY
1687 Enable checks on FPGA configuration interface busy
1688 status by the configuration function. This option
1689 will require a board or device specific function to
1694 If defined, a function that provides delays in the FPGA
1695 configuration driver.
1697 CONFIG_SYS_FPGA_CHECK_CTRLC
1698 Allow Control-C to interrupt FPGA configuration
1700 CONFIG_SYS_FPGA_CHECK_ERROR
1702 Check for configuration errors during FPGA bitfile
1703 loading. For example, abort during Virtex II
1704 configuration if the INIT_B line goes low (which
1705 indicated a CRC error).
1707 CONFIG_SYS_FPGA_WAIT_INIT
1709 Maximum time to wait for the INIT_B line to deassert
1710 after PROB_B has been deasserted during a Virtex II
1711 FPGA configuration sequence. The default time is 500
1714 CONFIG_SYS_FPGA_WAIT_BUSY
1716 Maximum time to wait for BUSY to deassert during
1717 Virtex II FPGA configuration. The default is 5 ms.
1719 CONFIG_SYS_FPGA_WAIT_CONFIG
1721 Time to wait after FPGA configuration. The default is
1724 - Configuration Management:
1727 If defined, this string will be added to the U-Boot
1728 version information (U_BOOT_VERSION)
1730 - Vendor Parameter Protection:
1732 U-Boot considers the values of the environment
1733 variables "serial#" (Board Serial Number) and
1734 "ethaddr" (Ethernet Address) to be parameters that
1735 are set once by the board vendor / manufacturer, and
1736 protects these variables from casual modification by
1737 the user. Once set, these variables are read-only,
1738 and write or delete attempts are rejected. You can
1739 change this behaviour:
1741 If CONFIG_ENV_OVERWRITE is #defined in your config
1742 file, the write protection for vendor parameters is
1743 completely disabled. Anybody can change or delete
1746 Alternatively, if you #define _both_ CONFIG_ETHADDR
1747 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1748 Ethernet address is installed in the environment,
1749 which can be changed exactly ONCE by the user. [The
1750 serial# is unaffected by this, i. e. it remains
1756 Define this variable to enable the reservation of
1757 "protected RAM", i. e. RAM which is not overwritten
1758 by U-Boot. Define CONFIG_PRAM to hold the number of
1759 kB you want to reserve for pRAM. You can overwrite
1760 this default value by defining an environment
1761 variable "pram" to the number of kB you want to
1762 reserve. Note that the board info structure will
1763 still show the full amount of RAM. If pRAM is
1764 reserved, a new environment variable "mem" will
1765 automatically be defined to hold the amount of
1766 remaining RAM in a form that can be passed as boot
1767 argument to Linux, for instance like that:
1769 setenv bootargs ... mem=\${mem}
1772 This way you can tell Linux not to use this memory,
1773 either, which results in a memory region that will
1774 not be affected by reboots.
1776 *WARNING* If your board configuration uses automatic
1777 detection of the RAM size, you must make sure that
1778 this memory test is non-destructive. So far, the
1779 following board configurations are known to be
1782 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1783 HERMES, IP860, RPXlite, LWMON, LANTEC,
1789 Define this variable to stop the system in case of a
1790 fatal error, so that you have to reset it manually.
1791 This is probably NOT a good idea for an embedded
1792 system where you want the system to reboot
1793 automatically as fast as possible, but it may be
1794 useful during development since you can try to debug
1795 the conditions that lead to the situation.
1797 CONFIG_NET_RETRY_COUNT
1799 This variable defines the number of retries for
1800 network operations like ARP, RARP, TFTP, or BOOTP
1801 before giving up the operation. If not defined, a
1802 default value of 5 is used.
1806 Timeout waiting for an ARP reply in milliseconds.
1808 - Command Interpreter:
1809 CONFIG_AUTO_COMPLETE
1811 Enable auto completion of commands using TAB.
1813 Note that this feature has NOT been implemented yet
1814 for the "hush" shell.
1817 CONFIG_SYS_HUSH_PARSER
1819 Define this variable to enable the "hush" shell (from
1820 Busybox) as command line interpreter, thus enabling
1821 powerful command line syntax like
1822 if...then...else...fi conditionals or `&&' and '||'
1823 constructs ("shell scripts").
1825 If undefined, you get the old, much simpler behaviour
1826 with a somewhat smaller memory footprint.
1829 CONFIG_SYS_PROMPT_HUSH_PS2
1831 This defines the secondary prompt string, which is
1832 printed when the command interpreter needs more input
1833 to complete a command. Usually "> ".
1837 In the current implementation, the local variables
1838 space and global environment variables space are
1839 separated. Local variables are those you define by
1840 simply typing `name=value'. To access a local
1841 variable later on, you have write `$name' or
1842 `${name}'; to execute the contents of a variable
1843 directly type `$name' at the command prompt.
1845 Global environment variables are those you use
1846 setenv/printenv to work with. To run a command stored
1847 in such a variable, you need to use the run command,
1848 and you must not use the '$' sign to access them.
1850 To store commands and special characters in a
1851 variable, please use double quotation marks
1852 surrounding the whole text of the variable, instead
1853 of the backslashes before semicolons and special
1856 - Commandline Editing and History:
1857 CONFIG_CMDLINE_EDITING
1859 Enable editing and History functions for interactive
1860 commandline input operations
1862 - Default Environment:
1863 CONFIG_EXTRA_ENV_SETTINGS
1865 Define this to contain any number of null terminated
1866 strings (variable = value pairs) that will be part of
1867 the default environment compiled into the boot image.
1869 For example, place something like this in your
1870 board's config file:
1872 #define CONFIG_EXTRA_ENV_SETTINGS \
1876 Warning: This method is based on knowledge about the
1877 internal format how the environment is stored by the
1878 U-Boot code. This is NOT an official, exported
1879 interface! Although it is unlikely that this format
1880 will change soon, there is no guarantee either.
1881 You better know what you are doing here.
1883 Note: overly (ab)use of the default environment is
1884 discouraged. Make sure to check other ways to preset
1885 the environment like the "source" command or the
1888 - DataFlash Support:
1889 CONFIG_HAS_DATAFLASH
1891 Defining this option enables DataFlash features and
1892 allows to read/write in Dataflash via the standard
1895 - SystemACE Support:
1898 Adding this option adds support for Xilinx SystemACE
1899 chips attached via some sort of local bus. The address
1900 of the chip must also be defined in the
1901 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1903 #define CONFIG_SYSTEMACE
1904 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1906 When SystemACE support is added, the "ace" device type
1907 becomes available to the fat commands, i.e. fatls.
1909 - TFTP Fixed UDP Port:
1912 If this is defined, the environment variable tftpsrcp
1913 is used to supply the TFTP UDP source port value.
1914 If tftpsrcp isn't defined, the normal pseudo-random port
1915 number generator is used.
1917 Also, the environment variable tftpdstp is used to supply
1918 the TFTP UDP destination port value. If tftpdstp isn't
1919 defined, the normal port 69 is used.
1921 The purpose for tftpsrcp is to allow a TFTP server to
1922 blindly start the TFTP transfer using the pre-configured
1923 target IP address and UDP port. This has the effect of
1924 "punching through" the (Windows XP) firewall, allowing
1925 the remainder of the TFTP transfer to proceed normally.
1926 A better solution is to properly configure the firewall,
1927 but sometimes that is not allowed.
1929 - Show boot progress:
1930 CONFIG_SHOW_BOOT_PROGRESS
1932 Defining this option allows to add some board-
1933 specific code (calling a user-provided function
1934 "show_boot_progress(int)") that enables you to show
1935 the system's boot progress on some display (for
1936 example, some LED's) on your board. At the moment,
1937 the following checkpoints are implemented:
1939 Legacy uImage format:
1942 1 common/cmd_bootm.c before attempting to boot an image
1943 -1 common/cmd_bootm.c Image header has bad magic number
1944 2 common/cmd_bootm.c Image header has correct magic number
1945 -2 common/cmd_bootm.c Image header has bad checksum
1946 3 common/cmd_bootm.c Image header has correct checksum
1947 -3 common/cmd_bootm.c Image data has bad checksum
1948 4 common/cmd_bootm.c Image data has correct checksum
1949 -4 common/cmd_bootm.c Image is for unsupported architecture
1950 5 common/cmd_bootm.c Architecture check OK
1951 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1952 6 common/cmd_bootm.c Image Type check OK
1953 -6 common/cmd_bootm.c gunzip uncompression error
1954 -7 common/cmd_bootm.c Unimplemented compression type
1955 7 common/cmd_bootm.c Uncompression OK
1956 8 common/cmd_bootm.c No uncompress/copy overwrite error
1957 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1959 9 common/image.c Start initial ramdisk verification
1960 -10 common/image.c Ramdisk header has bad magic number
1961 -11 common/image.c Ramdisk header has bad checksum
1962 10 common/image.c Ramdisk header is OK
1963 -12 common/image.c Ramdisk data has bad checksum
1964 11 common/image.c Ramdisk data has correct checksum
1965 12 common/image.c Ramdisk verification complete, start loading
1966 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1967 13 common/image.c Start multifile image verification
1968 14 common/image.c No initial ramdisk, no multifile, continue.
1970 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
1972 -30 arch/powerpc/lib/board.c Fatal error, hang the system
1973 -31 post/post.c POST test failed, detected by post_output_backlog()
1974 -32 post/post.c POST test failed, detected by post_run_single()
1976 34 common/cmd_doc.c before loading a Image from a DOC device
1977 -35 common/cmd_doc.c Bad usage of "doc" command
1978 35 common/cmd_doc.c correct usage of "doc" command
1979 -36 common/cmd_doc.c No boot device
1980 36 common/cmd_doc.c correct boot device
1981 -37 common/cmd_doc.c Unknown Chip ID on boot device
1982 37 common/cmd_doc.c correct chip ID found, device available
1983 -38 common/cmd_doc.c Read Error on boot device
1984 38 common/cmd_doc.c reading Image header from DOC device OK
1985 -39 common/cmd_doc.c Image header has bad magic number
1986 39 common/cmd_doc.c Image header has correct magic number
1987 -40 common/cmd_doc.c Error reading Image from DOC device
1988 40 common/cmd_doc.c Image header has correct magic number
1989 41 common/cmd_ide.c before loading a Image from a IDE device
1990 -42 common/cmd_ide.c Bad usage of "ide" command
1991 42 common/cmd_ide.c correct usage of "ide" command
1992 -43 common/cmd_ide.c No boot device
1993 43 common/cmd_ide.c boot device found
1994 -44 common/cmd_ide.c Device not available
1995 44 common/cmd_ide.c Device available
1996 -45 common/cmd_ide.c wrong partition selected
1997 45 common/cmd_ide.c partition selected
1998 -46 common/cmd_ide.c Unknown partition table
1999 46 common/cmd_ide.c valid partition table found
2000 -47 common/cmd_ide.c Invalid partition type
2001 47 common/cmd_ide.c correct partition type
2002 -48 common/cmd_ide.c Error reading Image Header on boot device
2003 48 common/cmd_ide.c reading Image Header from IDE device OK
2004 -49 common/cmd_ide.c Image header has bad magic number
2005 49 common/cmd_ide.c Image header has correct magic number
2006 -50 common/cmd_ide.c Image header has bad checksum
2007 50 common/cmd_ide.c Image header has correct checksum
2008 -51 common/cmd_ide.c Error reading Image from IDE device
2009 51 common/cmd_ide.c reading Image from IDE device OK
2010 52 common/cmd_nand.c before loading a Image from a NAND device
2011 -53 common/cmd_nand.c Bad usage of "nand" command
2012 53 common/cmd_nand.c correct usage of "nand" command
2013 -54 common/cmd_nand.c No boot device
2014 54 common/cmd_nand.c boot device found
2015 -55 common/cmd_nand.c Unknown Chip ID on boot device
2016 55 common/cmd_nand.c correct chip ID found, device available
2017 -56 common/cmd_nand.c Error reading Image Header on boot device
2018 56 common/cmd_nand.c reading Image Header from NAND device OK
2019 -57 common/cmd_nand.c Image header has bad magic number
2020 57 common/cmd_nand.c Image header has correct magic number
2021 -58 common/cmd_nand.c Error reading Image from NAND device
2022 58 common/cmd_nand.c reading Image from NAND device OK
2024 -60 common/env_common.c Environment has a bad CRC, using default
2026 64 net/eth.c starting with Ethernet configuration.
2027 -64 net/eth.c no Ethernet found.
2028 65 net/eth.c Ethernet found.
2030 -80 common/cmd_net.c usage wrong
2031 80 common/cmd_net.c before calling NetLoop()
2032 -81 common/cmd_net.c some error in NetLoop() occurred
2033 81 common/cmd_net.c NetLoop() back without error
2034 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2035 82 common/cmd_net.c trying automatic boot
2036 83 common/cmd_net.c running "source" command
2037 -83 common/cmd_net.c some error in automatic boot or "source" command
2038 84 common/cmd_net.c end without errors
2043 100 common/cmd_bootm.c Kernel FIT Image has correct format
2044 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2045 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2046 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2047 102 common/cmd_bootm.c Kernel unit name specified
2048 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2049 103 common/cmd_bootm.c Found configuration node
2050 104 common/cmd_bootm.c Got kernel subimage node offset
2051 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2052 105 common/cmd_bootm.c Kernel subimage hash verification OK
2053 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2054 106 common/cmd_bootm.c Architecture check OK
2055 -106 common/cmd_bootm.c Kernel subimage has wrong type
2056 107 common/cmd_bootm.c Kernel subimage type OK
2057 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2058 108 common/cmd_bootm.c Got kernel subimage data/size
2059 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2060 -109 common/cmd_bootm.c Can't get kernel subimage type
2061 -110 common/cmd_bootm.c Can't get kernel subimage comp
2062 -111 common/cmd_bootm.c Can't get kernel subimage os
2063 -112 common/cmd_bootm.c Can't get kernel subimage load address
2064 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2066 120 common/image.c Start initial ramdisk verification
2067 -120 common/image.c Ramdisk FIT image has incorrect format
2068 121 common/image.c Ramdisk FIT image has correct format
2069 122 common/image.c No ramdisk subimage unit name, using configuration
2070 -122 common/image.c Can't get configuration for ramdisk subimage
2071 123 common/image.c Ramdisk unit name specified
2072 -124 common/image.c Can't get ramdisk subimage node offset
2073 125 common/image.c Got ramdisk subimage node offset
2074 -125 common/image.c Ramdisk subimage hash verification failed
2075 126 common/image.c Ramdisk subimage hash verification OK
2076 -126 common/image.c Ramdisk subimage for unsupported architecture
2077 127 common/image.c Architecture check OK
2078 -127 common/image.c Can't get ramdisk subimage data/size
2079 128 common/image.c Got ramdisk subimage data/size
2080 129 common/image.c Can't get ramdisk load address
2081 -129 common/image.c Got ramdisk load address
2083 -130 common/cmd_doc.c Incorrect FIT image format
2084 131 common/cmd_doc.c FIT image format OK
2086 -140 common/cmd_ide.c Incorrect FIT image format
2087 141 common/cmd_ide.c FIT image format OK
2089 -150 common/cmd_nand.c Incorrect FIT image format
2090 151 common/cmd_nand.c FIT image format OK
2092 - Automatic software updates via TFTP server
2094 CONFIG_UPDATE_TFTP_CNT_MAX
2095 CONFIG_UPDATE_TFTP_MSEC_MAX
2097 These options enable and control the auto-update feature;
2098 for a more detailed description refer to doc/README.update.
2100 - MTD Support (mtdparts command, UBI support)
2103 Adds the MTD device infrastructure from the Linux kernel.
2104 Needed for mtdparts command support.
2106 CONFIG_MTD_PARTITIONS
2108 Adds the MTD partitioning infrastructure from the Linux
2109 kernel. Needed for UBI support.
2115 [so far only for SMDK2400 and TRAB boards]
2117 - Modem support enable:
2118 CONFIG_MODEM_SUPPORT
2120 - RTS/CTS Flow control enable:
2123 - Modem debug support:
2124 CONFIG_MODEM_SUPPORT_DEBUG
2126 Enables debugging stuff (char screen[1024], dbg())
2127 for modem support. Useful only with BDI2000.
2129 - Interrupt support (PPC):
2131 There are common interrupt_init() and timer_interrupt()
2132 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2133 for CPU specific initialization. interrupt_init_cpu()
2134 should set decrementer_count to appropriate value. If
2135 CPU resets decrementer automatically after interrupt
2136 (ppc4xx) it should set decrementer_count to zero.
2137 timer_interrupt() calls timer_interrupt_cpu() for CPU
2138 specific handling. If board has watchdog / status_led
2139 / other_activity_monitor it works automatically from
2140 general timer_interrupt().
2144 In the target system modem support is enabled when a
2145 specific key (key combination) is pressed during
2146 power-on. Otherwise U-Boot will boot normally
2147 (autoboot). The key_pressed() function is called from
2148 board_init(). Currently key_pressed() is a dummy
2149 function, returning 1 and thus enabling modem
2152 If there are no modem init strings in the
2153 environment, U-Boot proceed to autoboot; the
2154 previous output (banner, info printfs) will be
2157 See also: doc/README.Modem
2160 Configuration Settings:
2161 -----------------------
2163 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2164 undefine this when you're short of memory.
2166 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2167 width of the commands listed in the 'help' command output.
2169 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2170 prompt for user input.
2172 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2174 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2176 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2178 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2179 the application (usually a Linux kernel) when it is
2182 - CONFIG_SYS_BAUDRATE_TABLE:
2183 List of legal baudrate settings for this board.
2185 - CONFIG_SYS_CONSOLE_INFO_QUIET
2186 Suppress display of console information at boot.
2188 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2189 If the board specific function
2190 extern int overwrite_console (void);
2191 returns 1, the stdin, stderr and stdout are switched to the
2192 serial port, else the settings in the environment are used.
2194 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2195 Enable the call to overwrite_console().
2197 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2198 Enable overwrite of previous console environment settings.
2200 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2201 Begin and End addresses of the area used by the
2204 - CONFIG_SYS_ALT_MEMTEST:
2205 Enable an alternate, more extensive memory test.
2207 - CONFIG_SYS_MEMTEST_SCRATCH:
2208 Scratch address used by the alternate memory test
2209 You only need to set this if address zero isn't writeable
2211 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2212 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2213 this specified memory area will get subtracted from the top
2214 (end) of RAM and won't get "touched" at all by U-Boot. By
2215 fixing up gd->ram_size the Linux kernel should gets passed
2216 the now "corrected" memory size and won't touch it either.
2217 This should work for arch/ppc and arch/powerpc. Only Linux
2218 board ports in arch/powerpc with bootwrapper support that
2219 recalculate the memory size from the SDRAM controller setup
2220 will have to get fixed in Linux additionally.
2222 This option can be used as a workaround for the 440EPx/GRx
2223 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2226 WARNING: Please make sure that this value is a multiple of
2227 the Linux page size (normally 4k). If this is not the case,
2228 then the end address of the Linux memory will be located at a
2229 non page size aligned address and this could cause major
2232 - CONFIG_SYS_TFTP_LOADADDR:
2233 Default load address for network file downloads
2235 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2236 Enable temporary baudrate change while serial download
2238 - CONFIG_SYS_SDRAM_BASE:
2239 Physical start address of SDRAM. _Must_ be 0 here.
2241 - CONFIG_SYS_MBIO_BASE:
2242 Physical start address of Motherboard I/O (if using a
2245 - CONFIG_SYS_FLASH_BASE:
2246 Physical start address of Flash memory.
2248 - CONFIG_SYS_MONITOR_BASE:
2249 Physical start address of boot monitor code (set by
2250 make config files to be same as the text base address
2251 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2252 CONFIG_SYS_FLASH_BASE when booting from flash.
2254 - CONFIG_SYS_MONITOR_LEN:
2255 Size of memory reserved for monitor code, used to
2256 determine _at_compile_time_ (!) if the environment is
2257 embedded within the U-Boot image, or in a separate
2260 - CONFIG_SYS_MALLOC_LEN:
2261 Size of DRAM reserved for malloc() use.
2263 - CONFIG_SYS_BOOTM_LEN:
2264 Normally compressed uImages are limited to an
2265 uncompressed size of 8 MBytes. If this is not enough,
2266 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2267 to adjust this setting to your needs.
2269 - CONFIG_SYS_BOOTMAPSZ:
2270 Maximum size of memory mapped by the startup code of
2271 the Linux kernel; all data that must be processed by
2272 the Linux kernel (bd_info, boot arguments, FDT blob if
2273 used) must be put below this limit, unless "bootm_low"
2274 enviroment variable is defined and non-zero. In such case
2275 all data for the Linux kernel must be between "bootm_low"
2276 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2278 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2279 Enable initrd_high functionality. If defined then the
2280 initrd_high feature is enabled and the bootm ramdisk subcommand
2283 - CONFIG_SYS_BOOT_GET_CMDLINE:
2284 Enables allocating and saving kernel cmdline in space between
2285 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2287 - CONFIG_SYS_BOOT_GET_KBD:
2288 Enables allocating and saving a kernel copy of the bd_info in
2289 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2291 - CONFIG_SYS_MAX_FLASH_BANKS:
2292 Max number of Flash memory banks
2294 - CONFIG_SYS_MAX_FLASH_SECT:
2295 Max number of sectors on a Flash chip
2297 - CONFIG_SYS_FLASH_ERASE_TOUT:
2298 Timeout for Flash erase operations (in ms)
2300 - CONFIG_SYS_FLASH_WRITE_TOUT:
2301 Timeout for Flash write operations (in ms)
2303 - CONFIG_SYS_FLASH_LOCK_TOUT
2304 Timeout for Flash set sector lock bit operation (in ms)
2306 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2307 Timeout for Flash clear lock bits operation (in ms)
2309 - CONFIG_SYS_FLASH_PROTECTION
2310 If defined, hardware flash sectors protection is used
2311 instead of U-Boot software protection.
2313 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2315 Enable TFTP transfers directly to flash memory;
2316 without this option such a download has to be
2317 performed in two steps: (1) download to RAM, and (2)
2318 copy from RAM to flash.
2320 The two-step approach is usually more reliable, since
2321 you can check if the download worked before you erase
2322 the flash, but in some situations (when system RAM is
2323 too limited to allow for a temporary copy of the
2324 downloaded image) this option may be very useful.
2326 - CONFIG_SYS_FLASH_CFI:
2327 Define if the flash driver uses extra elements in the
2328 common flash structure for storing flash geometry.
2330 - CONFIG_FLASH_CFI_DRIVER
2331 This option also enables the building of the cfi_flash driver
2332 in the drivers directory
2334 - CONFIG_FLASH_CFI_MTD
2335 This option enables the building of the cfi_mtd driver
2336 in the drivers directory. The driver exports CFI flash
2339 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2340 Use buffered writes to flash.
2342 - CONFIG_FLASH_SPANSION_S29WS_N
2343 s29ws-n MirrorBit flash has non-standard addresses for buffered
2346 - CONFIG_SYS_FLASH_QUIET_TEST
2347 If this option is defined, the common CFI flash doesn't
2348 print it's warning upon not recognized FLASH banks. This
2349 is useful, if some of the configured banks are only
2350 optionally available.
2352 - CONFIG_FLASH_SHOW_PROGRESS
2353 If defined (must be an integer), print out countdown
2354 digits and dots. Recommended value: 45 (9..1) for 80
2355 column displays, 15 (3..1) for 40 column displays.
2357 - CONFIG_SYS_RX_ETH_BUFFER:
2358 Defines the number of Ethernet receive buffers. On some
2359 Ethernet controllers it is recommended to set this value
2360 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2361 buffers can be full shortly after enabling the interface
2362 on high Ethernet traffic.
2363 Defaults to 4 if not defined.
2365 - CONFIG_ENV_MAX_ENTRIES
2367 Maximum number of entries in the hash table that is used
2368 internally to store the environment settings. The default
2369 setting is supposed to be generous and should work in most
2370 cases. This setting can be used to tune behaviour; see
2371 lib/hashtable.c for details.
2373 The following definitions that deal with the placement and management
2374 of environment data (variable area); in general, we support the
2375 following configurations:
2377 - CONFIG_ENV_IS_IN_FLASH:
2379 Define this if the environment is in flash memory.
2381 a) The environment occupies one whole flash sector, which is
2382 "embedded" in the text segment with the U-Boot code. This
2383 happens usually with "bottom boot sector" or "top boot
2384 sector" type flash chips, which have several smaller
2385 sectors at the start or the end. For instance, such a
2386 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2387 such a case you would place the environment in one of the
2388 4 kB sectors - with U-Boot code before and after it. With
2389 "top boot sector" type flash chips, you would put the
2390 environment in one of the last sectors, leaving a gap
2391 between U-Boot and the environment.
2393 - CONFIG_ENV_OFFSET:
2395 Offset of environment data (variable area) to the
2396 beginning of flash memory; for instance, with bottom boot
2397 type flash chips the second sector can be used: the offset
2398 for this sector is given here.
2400 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2404 This is just another way to specify the start address of
2405 the flash sector containing the environment (instead of
2408 - CONFIG_ENV_SECT_SIZE:
2410 Size of the sector containing the environment.
2413 b) Sometimes flash chips have few, equal sized, BIG sectors.
2414 In such a case you don't want to spend a whole sector for
2419 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2420 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2421 of this flash sector for the environment. This saves
2422 memory for the RAM copy of the environment.
2424 It may also save flash memory if you decide to use this
2425 when your environment is "embedded" within U-Boot code,
2426 since then the remainder of the flash sector could be used
2427 for U-Boot code. It should be pointed out that this is
2428 STRONGLY DISCOURAGED from a robustness point of view:
2429 updating the environment in flash makes it always
2430 necessary to erase the WHOLE sector. If something goes
2431 wrong before the contents has been restored from a copy in
2432 RAM, your target system will be dead.
2434 - CONFIG_ENV_ADDR_REDUND
2435 CONFIG_ENV_SIZE_REDUND
2437 These settings describe a second storage area used to hold
2438 a redundant copy of the environment data, so that there is
2439 a valid backup copy in case there is a power failure during
2440 a "saveenv" operation.
2442 BE CAREFUL! Any changes to the flash layout, and some changes to the
2443 source code will make it necessary to adapt <board>/u-boot.lds*
2447 - CONFIG_ENV_IS_IN_NVRAM:
2449 Define this if you have some non-volatile memory device
2450 (NVRAM, battery buffered SRAM) which you want to use for the
2456 These two #defines are used to determine the memory area you
2457 want to use for environment. It is assumed that this memory
2458 can just be read and written to, without any special
2461 BE CAREFUL! The first access to the environment happens quite early
2462 in U-Boot initalization (when we try to get the setting of for the
2463 console baudrate). You *MUST* have mapped your NVRAM area then, or
2466 Please note that even with NVRAM we still use a copy of the
2467 environment in RAM: we could work on NVRAM directly, but we want to
2468 keep settings there always unmodified except somebody uses "saveenv"
2469 to save the current settings.
2472 - CONFIG_ENV_IS_IN_EEPROM:
2474 Use this if you have an EEPROM or similar serial access
2475 device and a driver for it.
2477 - CONFIG_ENV_OFFSET:
2480 These two #defines specify the offset and size of the
2481 environment area within the total memory of your EEPROM.
2483 - CONFIG_SYS_I2C_EEPROM_ADDR:
2484 If defined, specified the chip address of the EEPROM device.
2485 The default address is zero.
2487 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2488 If defined, the number of bits used to address bytes in a
2489 single page in the EEPROM device. A 64 byte page, for example
2490 would require six bits.
2492 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2493 If defined, the number of milliseconds to delay between
2494 page writes. The default is zero milliseconds.
2496 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2497 The length in bytes of the EEPROM memory array address. Note
2498 that this is NOT the chip address length!
2500 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2501 EEPROM chips that implement "address overflow" are ones
2502 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2503 address and the extra bits end up in the "chip address" bit
2504 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2507 Note that we consider the length of the address field to
2508 still be one byte because the extra address bits are hidden
2509 in the chip address.
2511 - CONFIG_SYS_EEPROM_SIZE:
2512 The size in bytes of the EEPROM device.
2514 - CONFIG_ENV_EEPROM_IS_ON_I2C
2515 define this, if you have I2C and SPI activated, and your
2516 EEPROM, which holds the environment, is on the I2C bus.
2518 - CONFIG_I2C_ENV_EEPROM_BUS
2519 if you have an Environment on an EEPROM reached over
2520 I2C muxes, you can define here, how to reach this
2521 EEPROM. For example:
2523 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2525 EEPROM which holds the environment, is reached over
2526 a pca9547 i2c mux with address 0x70, channel 3.
2528 - CONFIG_ENV_IS_IN_DATAFLASH:
2530 Define this if you have a DataFlash memory device which you
2531 want to use for the environment.
2533 - CONFIG_ENV_OFFSET:
2537 These three #defines specify the offset and size of the
2538 environment area within the total memory of your DataFlash placed
2539 at the specified address.
2541 - CONFIG_ENV_IS_IN_NAND:
2543 Define this if you have a NAND device which you want to use
2544 for the environment.
2546 - CONFIG_ENV_OFFSET:
2549 These two #defines specify the offset and size of the environment
2550 area within the first NAND device. CONFIG_ENV_OFFSET must be
2551 aligned to an erase block boundary.
2553 - CONFIG_ENV_OFFSET_REDUND (optional):
2555 This setting describes a second storage area of CONFIG_ENV_SIZE
2556 size used to hold a redundant copy of the environment data, so
2557 that there is a valid backup copy in case there is a power failure
2558 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2559 aligned to an erase block boundary.
2561 - CONFIG_ENV_RANGE (optional):
2563 Specifies the length of the region in which the environment
2564 can be written. This should be a multiple of the NAND device's
2565 block size. Specifying a range with more erase blocks than
2566 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2567 the range to be avoided.
2569 - CONFIG_ENV_OFFSET_OOB (optional):
2571 Enables support for dynamically retrieving the offset of the
2572 environment from block zero's out-of-band data. The
2573 "nand env.oob" command can be used to record this offset.
2574 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2575 using CONFIG_ENV_OFFSET_OOB.
2577 - CONFIG_NAND_ENV_DST
2579 Defines address in RAM to which the nand_spl code should copy the
2580 environment. If redundant environment is used, it will be copied to
2581 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2583 - CONFIG_SYS_SPI_INIT_OFFSET
2585 Defines offset to the initial SPI buffer area in DPRAM. The
2586 area is used at an early stage (ROM part) if the environment
2587 is configured to reside in the SPI EEPROM: We need a 520 byte
2588 scratch DPRAM area. It is used between the two initialization
2589 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2590 to be a good choice since it makes it far enough from the
2591 start of the data area as well as from the stack pointer.
2593 Please note that the environment is read-only until the monitor
2594 has been relocated to RAM and a RAM copy of the environment has been
2595 created; also, when using EEPROM you will have to use getenv_f()
2596 until then to read environment variables.
2598 The environment is protected by a CRC32 checksum. Before the monitor
2599 is relocated into RAM, as a result of a bad CRC you will be working
2600 with the compiled-in default environment - *silently*!!! [This is
2601 necessary, because the first environment variable we need is the
2602 "baudrate" setting for the console - if we have a bad CRC, we don't
2603 have any device yet where we could complain.]
2605 Note: once the monitor has been relocated, then it will complain if
2606 the default environment is used; a new CRC is computed as soon as you
2607 use the "saveenv" command to store a valid environment.
2609 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2610 Echo the inverted Ethernet link state to the fault LED.
2612 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2613 also needs to be defined.
2615 - CONFIG_SYS_FAULT_MII_ADDR:
2616 MII address of the PHY to check for the Ethernet link state.
2618 - CONFIG_NS16550_MIN_FUNCTIONS:
2619 Define this if you desire to only have use of the NS16550_init
2620 and NS16550_putc functions for the serial driver located at
2621 drivers/serial/ns16550.c. This option is useful for saving
2622 space for already greatly restricted images, including but not
2623 limited to NAND_SPL configurations.
2625 Low Level (hardware related) configuration options:
2626 ---------------------------------------------------
2628 - CONFIG_SYS_CACHELINE_SIZE:
2629 Cache Line Size of the CPU.
2631 - CONFIG_SYS_DEFAULT_IMMR:
2632 Default address of the IMMR after system reset.
2634 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2635 and RPXsuper) to be able to adjust the position of
2636 the IMMR register after a reset.
2638 - Floppy Disk Support:
2639 CONFIG_SYS_FDC_DRIVE_NUMBER
2641 the default drive number (default value 0)
2643 CONFIG_SYS_ISA_IO_STRIDE
2645 defines the spacing between FDC chipset registers
2648 CONFIG_SYS_ISA_IO_OFFSET
2650 defines the offset of register from address. It
2651 depends on which part of the data bus is connected to
2652 the FDC chipset. (default value 0)
2654 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2655 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2658 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2659 fdc_hw_init() is called at the beginning of the FDC
2660 setup. fdc_hw_init() must be provided by the board
2661 source code. It is used to make hardware dependant
2664 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2665 DO NOT CHANGE unless you know exactly what you're
2666 doing! (11-4) [MPC8xx/82xx systems only]
2668 - CONFIG_SYS_INIT_RAM_ADDR:
2670 Start address of memory area that can be used for
2671 initial data and stack; please note that this must be
2672 writable memory that is working WITHOUT special
2673 initialization, i. e. you CANNOT use normal RAM which
2674 will become available only after programming the
2675 memory controller and running certain initialization
2678 U-Boot uses the following memory types:
2679 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2680 - MPC824X: data cache
2681 - PPC4xx: data cache
2683 - CONFIG_SYS_GBL_DATA_OFFSET:
2685 Offset of the initial data structure in the memory
2686 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2687 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2688 data is located at the end of the available space
2689 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2690 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2691 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2692 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2695 On the MPC824X (or other systems that use the data
2696 cache for initial memory) the address chosen for
2697 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2698 point to an otherwise UNUSED address space between
2699 the top of RAM and the start of the PCI space.
2701 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2703 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2705 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2707 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2709 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2711 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2713 - CONFIG_SYS_OR_TIMING_SDRAM:
2716 - CONFIG_SYS_MAMR_PTA:
2717 periodic timer for refresh
2719 - CONFIG_SYS_DER: Debug Event Register (37-47)
2721 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2722 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2723 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2724 CONFIG_SYS_BR1_PRELIM:
2725 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2727 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2728 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2729 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2730 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2732 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2733 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2734 Machine Mode Register and Memory Periodic Timer
2735 Prescaler definitions (SDRAM timing)
2737 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2738 enable I2C microcode relocation patch (MPC8xx);
2739 define relocation offset in DPRAM [DSP2]
2741 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2742 enable SMC microcode relocation patch (MPC8xx);
2743 define relocation offset in DPRAM [SMC1]
2745 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2746 enable SPI microcode relocation patch (MPC8xx);
2747 define relocation offset in DPRAM [SCC4]
2749 - CONFIG_SYS_USE_OSCCLK:
2750 Use OSCM clock mode on MBX8xx board. Be careful,
2751 wrong setting might damage your board. Read
2752 doc/README.MBX before setting this variable!
2754 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2755 Offset of the bootmode word in DPRAM used by post
2756 (Power On Self Tests). This definition overrides
2757 #define'd default value in commproc.h resp.
2760 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2761 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2762 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2763 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2764 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2765 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2766 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2767 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2768 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
2770 - CONFIG_PCI_DISABLE_PCIE:
2771 Disable PCI-Express on systems where it is supported but not
2775 Get DDR timing information from an I2C EEPROM. Common
2776 with pluggable memory modules such as SODIMMs
2779 I2C address of the SPD EEPROM
2781 - CONFIG_SYS_SPD_BUS_NUM
2782 If SPD EEPROM is on an I2C bus other than the first
2783 one, specify here. Note that the value must resolve
2784 to something your driver can deal with.
2786 - CONFIG_SYS_83XX_DDR_USES_CS0
2787 Only for 83xx systems. If specified, then DDR should
2788 be configured using CS0 and CS1 instead of CS2 and CS3.
2790 - CONFIG_ETHER_ON_FEC[12]
2791 Define to enable FEC[12] on a 8xx series processor.
2793 - CONFIG_FEC[12]_PHY
2794 Define to the hardcoded PHY address which corresponds
2795 to the given FEC; i. e.
2796 #define CONFIG_FEC1_PHY 4
2797 means that the PHY with address 4 is connected to FEC1
2799 When set to -1, means to probe for first available.
2801 - CONFIG_FEC[12]_PHY_NORXERR
2802 The PHY does not have a RXERR line (RMII only).
2803 (so program the FEC to ignore it).
2806 Enable RMII mode for all FECs.
2807 Note that this is a global option, we can't
2808 have one FEC in standard MII mode and another in RMII mode.
2810 - CONFIG_CRC32_VERIFY
2811 Add a verify option to the crc32 command.
2814 => crc32 -v <address> <count> <crc32>
2816 Where address/count indicate a memory area
2817 and crc32 is the correct crc32 which the
2821 Add the "loopw" memory command. This only takes effect if
2822 the memory commands are activated globally (CONFIG_CMD_MEM).
2825 Add the "mdc" and "mwc" memory commands. These are cyclic
2830 This command will print 4 bytes (10,11,12,13) each 500 ms.
2832 => mwc.l 100 12345678 10
2833 This command will write 12345678 to address 100 all 10 ms.
2835 This only takes effect if the memory commands are activated
2836 globally (CONFIG_CMD_MEM).
2838 - CONFIG_SKIP_LOWLEVEL_INIT
2839 [ARM only] If this variable is defined, then certain
2840 low level initializations (like setting up the memory
2841 controller) are omitted and/or U-Boot does not
2842 relocate itself into RAM.
2844 Normally this variable MUST NOT be defined. The only
2845 exception is when U-Boot is loaded (to RAM) by some
2846 other boot loader or by a debugger which performs
2847 these initializations itself.
2850 Modifies the behaviour of start.S when compiling a loader
2851 that is executed before the actual U-Boot. E.g. when
2852 compiling a NAND SPL.
2854 Building the Software:
2855 ======================
2857 Building U-Boot has been tested in several native build environments
2858 and in many different cross environments. Of course we cannot support
2859 all possibly existing versions of cross development tools in all
2860 (potentially obsolete) versions. In case of tool chain problems we
2861 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2862 which is extensively used to build and test U-Boot.
2864 If you are not using a native environment, it is assumed that you
2865 have GNU cross compiling tools available in your path. In this case,
2866 you must set the environment variable CROSS_COMPILE in your shell.
2867 Note that no changes to the Makefile or any other source files are
2868 necessary. For example using the ELDK on a 4xx CPU, please enter:
2870 $ CROSS_COMPILE=ppc_4xx-
2871 $ export CROSS_COMPILE
2873 Note: If you wish to generate Windows versions of the utilities in
2874 the tools directory you can use the MinGW toolchain
2875 (http://www.mingw.org). Set your HOST tools to the MinGW
2876 toolchain and execute 'make tools'. For example:
2878 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
2880 Binaries such as tools/mkimage.exe will be created which can
2881 be executed on computers running Windows.
2883 U-Boot is intended to be simple to build. After installing the
2884 sources you must configure U-Boot for one specific board type. This
2889 where "NAME_config" is the name of one of the existing configu-
2890 rations; see the main Makefile for supported names.
2892 Note: for some board special configuration names may exist; check if
2893 additional information is available from the board vendor; for
2894 instance, the TQM823L systems are available without (standard)
2895 or with LCD support. You can select such additional "features"
2896 when choosing the configuration, i. e.
2899 - will configure for a plain TQM823L, i. e. no LCD support
2901 make TQM823L_LCD_config
2902 - will configure for a TQM823L with U-Boot console on LCD
2907 Finally, type "make all", and you should get some working U-Boot
2908 images ready for download to / installation on your system:
2910 - "u-boot.bin" is a raw binary image
2911 - "u-boot" is an image in ELF binary format
2912 - "u-boot.srec" is in Motorola S-Record format
2914 By default the build is performed locally and the objects are saved
2915 in the source directory. One of the two methods can be used to change
2916 this behavior and build U-Boot to some external directory:
2918 1. Add O= to the make command line invocations:
2920 make O=/tmp/build distclean
2921 make O=/tmp/build NAME_config
2922 make O=/tmp/build all
2924 2. Set environment variable BUILD_DIR to point to the desired location:
2926 export BUILD_DIR=/tmp/build
2931 Note that the command line "O=" setting overrides the BUILD_DIR environment
2935 Please be aware that the Makefiles assume you are using GNU make, so
2936 for instance on NetBSD you might need to use "gmake" instead of
2940 If the system board that you have is not listed, then you will need
2941 to port U-Boot to your hardware platform. To do this, follow these
2944 1. Add a new configuration option for your board to the toplevel
2945 "Makefile" and to the "MAKEALL" script, using the existing
2946 entries as examples. Note that here and at many other places
2947 boards and other names are listed in alphabetical sort order. Please
2949 2. Create a new directory to hold your board specific code. Add any
2950 files you need. In your board directory, you will need at least
2951 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2952 3. Create a new configuration file "include/configs/<board>.h" for
2954 3. If you're porting U-Boot to a new CPU, then also create a new
2955 directory to hold your CPU specific code. Add any files you need.
2956 4. Run "make <board>_config" with your new name.
2957 5. Type "make", and you should get a working "u-boot.srec" file
2958 to be installed on your target system.
2959 6. Debug and solve any problems that might arise.
2960 [Of course, this last step is much harder than it sounds.]
2963 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2964 ==============================================================
2966 If you have modified U-Boot sources (for instance added a new board
2967 or support for new devices, a new CPU, etc.) you are expected to
2968 provide feedback to the other developers. The feedback normally takes
2969 the form of a "patch", i. e. a context diff against a certain (latest
2970 official or latest in the git repository) version of U-Boot sources.
2972 But before you submit such a patch, please verify that your modifi-
2973 cation did not break existing code. At least make sure that *ALL* of
2974 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2975 just run the "MAKEALL" script, which will configure and build U-Boot
2976 for ALL supported system. Be warned, this will take a while. You can
2977 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2978 environment variable to the script, i. e. to use the ELDK cross tools
2981 CROSS_COMPILE=ppc_8xx- MAKEALL
2983 or to build on a native PowerPC system you can type
2985 CROSS_COMPILE=' ' MAKEALL
2987 When using the MAKEALL script, the default behaviour is to build
2988 U-Boot in the source directory. This location can be changed by
2989 setting the BUILD_DIR environment variable. Also, for each target
2990 built, the MAKEALL script saves two log files (<target>.ERR and
2991 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2992 location can be changed by setting the MAKEALL_LOGDIR environment
2993 variable. For example:
2995 export BUILD_DIR=/tmp/build
2996 export MAKEALL_LOGDIR=/tmp/log
2997 CROSS_COMPILE=ppc_8xx- MAKEALL
2999 With the above settings build objects are saved in the /tmp/build,
3000 log files are saved in the /tmp/log and the source tree remains clean
3001 during the whole build process.
3004 See also "U-Boot Porting Guide" below.
3007 Monitor Commands - Overview:
3008 ============================
3010 go - start application at address 'addr'
3011 run - run commands in an environment variable
3012 bootm - boot application image from memory
3013 bootp - boot image via network using BootP/TFTP protocol
3014 tftpboot- boot image via network using TFTP protocol
3015 and env variables "ipaddr" and "serverip"
3016 (and eventually "gatewayip")
3017 rarpboot- boot image via network using RARP/TFTP protocol
3018 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3019 loads - load S-Record file over serial line
3020 loadb - load binary file over serial line (kermit mode)
3022 mm - memory modify (auto-incrementing)
3023 nm - memory modify (constant address)
3024 mw - memory write (fill)
3026 cmp - memory compare
3027 crc32 - checksum calculation
3028 i2c - I2C sub-system
3029 sspi - SPI utility commands
3030 base - print or set address offset
3031 printenv- print environment variables
3032 setenv - set environment variables
3033 saveenv - save environment variables to persistent storage
3034 protect - enable or disable FLASH write protection
3035 erase - erase FLASH memory
3036 flinfo - print FLASH memory information
3037 bdinfo - print Board Info structure
3038 iminfo - print header information for application image
3039 coninfo - print console devices and informations
3040 ide - IDE sub-system
3041 loop - infinite loop on address range
3042 loopw - infinite write loop on address range
3043 mtest - simple RAM test
3044 icache - enable or disable instruction cache
3045 dcache - enable or disable data cache
3046 reset - Perform RESET of the CPU
3047 echo - echo args to console
3048 version - print monitor version
3049 help - print online help
3050 ? - alias for 'help'
3053 Monitor Commands - Detailed Description:
3054 ========================================
3058 For now: just type "help <command>".
3061 Environment Variables:
3062 ======================
3064 U-Boot supports user configuration using Environment Variables which
3065 can be made persistent by saving to Flash memory.
3067 Environment Variables are set using "setenv", printed using
3068 "printenv", and saved to Flash using "saveenv". Using "setenv"
3069 without a value can be used to delete a variable from the
3070 environment. As long as you don't save the environment you are
3071 working with an in-memory copy. In case the Flash area containing the
3072 environment is erased by accident, a default environment is provided.
3074 Some configuration options can be set using Environment Variables.
3076 List of environment variables (most likely not complete):
3078 baudrate - see CONFIG_BAUDRATE
3080 bootdelay - see CONFIG_BOOTDELAY
3082 bootcmd - see CONFIG_BOOTCOMMAND
3084 bootargs - Boot arguments when booting an RTOS image
3086 bootfile - Name of the image to load with TFTP
3088 bootm_low - Memory range available for image processing in the bootm
3089 command can be restricted. This variable is given as
3090 a hexadecimal number and defines lowest address allowed
3091 for use by the bootm command. See also "bootm_size"
3092 environment variable. Address defined by "bootm_low" is
3093 also the base of the initial memory mapping for the Linux
3094 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
3096 bootm_size - Memory range available for image processing in the bootm
3097 command can be restricted. This variable is given as
3098 a hexadecimal number and defines the size of the region
3099 allowed for use by the bootm command. See also "bootm_low"
3100 environment variable.
3102 updatefile - Location of the software update file on a TFTP server, used
3103 by the automatic software update feature. Please refer to
3104 documentation in doc/README.update for more details.
3106 autoload - if set to "no" (any string beginning with 'n'),
3107 "bootp" will just load perform a lookup of the
3108 configuration from the BOOTP server, but not try to
3109 load any image using TFTP
3111 autostart - if set to "yes", an image loaded using the "bootp",
3112 "rarpboot", "tftpboot" or "diskboot" commands will
3113 be automatically started (by internally calling
3116 If set to "no", a standalone image passed to the
3117 "bootm" command will be copied to the load address
3118 (and eventually uncompressed), but NOT be started.
3119 This can be used to load and uncompress arbitrary
3122 i2cfast - (PPC405GP|PPC405EP only)
3123 if set to 'y' configures Linux I2C driver for fast
3124 mode (400kHZ). This environment variable is used in
3125 initialization code. So, for changes to be effective
3126 it must be saved and board must be reset.
3128 initrd_high - restrict positioning of initrd images:
3129 If this variable is not set, initrd images will be
3130 copied to the highest possible address in RAM; this
3131 is usually what you want since it allows for
3132 maximum initrd size. If for some reason you want to
3133 make sure that the initrd image is loaded below the
3134 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3135 variable to a value of "no" or "off" or "0".
3136 Alternatively, you can set it to a maximum upper
3137 address to use (U-Boot will still check that it
3138 does not overwrite the U-Boot stack and data).
3140 For instance, when you have a system with 16 MB
3141 RAM, and want to reserve 4 MB from use by Linux,
3142 you can do this by adding "mem=12M" to the value of
3143 the "bootargs" variable. However, now you must make
3144 sure that the initrd image is placed in the first
3145 12 MB as well - this can be done with
3147 setenv initrd_high 00c00000
3149 If you set initrd_high to 0xFFFFFFFF, this is an
3150 indication to U-Boot that all addresses are legal
3151 for the Linux kernel, including addresses in flash
3152 memory. In this case U-Boot will NOT COPY the
3153 ramdisk at all. This may be useful to reduce the
3154 boot time on your system, but requires that this
3155 feature is supported by your Linux kernel.
3157 ipaddr - IP address; needed for tftpboot command
3159 loadaddr - Default load address for commands like "bootp",
3160 "rarpboot", "tftpboot", "loadb" or "diskboot"
3162 loads_echo - see CONFIG_LOADS_ECHO
3164 serverip - TFTP server IP address; needed for tftpboot command
3166 bootretry - see CONFIG_BOOT_RETRY_TIME
3168 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3170 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3172 ethprime - When CONFIG_NET_MULTI is enabled controls which
3173 interface is used first.
3175 ethact - When CONFIG_NET_MULTI is enabled controls which
3176 interface is currently active. For example you
3177 can do the following
3179 => setenv ethact FEC
3180 => ping 192.168.0.1 # traffic sent on FEC
3181 => setenv ethact SCC
3182 => ping 10.0.0.1 # traffic sent on SCC
3184 ethrotate - When set to "no" U-Boot does not go through all
3185 available network interfaces.
3186 It just stays at the currently selected interface.
3188 netretry - When set to "no" each network operation will
3189 either succeed or fail without retrying.
3190 When set to "once" the network operation will
3191 fail when all the available network interfaces
3192 are tried once without success.
3193 Useful on scripts which control the retry operation
3196 npe_ucode - set load address for the NPE microcode
3198 tftpsrcport - If this is set, the value is used for TFTP's
3201 tftpdstport - If this is set, the value is used for TFTP's UDP
3202 destination port instead of the Well Know Port 69.
3204 tftpblocksize - Block size to use for TFTP transfers; if not set,
3205 we use the TFTP server's default block size
3207 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3208 seconds, minimum value is 1000 = 1 second). Defines
3209 when a packet is considered to be lost so it has to
3210 be retransmitted. The default is 5000 = 5 seconds.
3211 Lowering this value may make downloads succeed
3212 faster in networks with high packet loss rates or
3213 with unreliable TFTP servers.
3215 vlan - When set to a value < 4095 the traffic over
3216 Ethernet is encapsulated/received over 802.1q
3219 The following environment variables may be used and automatically
3220 updated by the network boot commands ("bootp" and "rarpboot"),
3221 depending the information provided by your boot server:
3223 bootfile - see above
3224 dnsip - IP address of your Domain Name Server
3225 dnsip2 - IP address of your secondary Domain Name Server
3226 gatewayip - IP address of the Gateway (Router) to use
3227 hostname - Target hostname
3229 netmask - Subnet Mask
3230 rootpath - Pathname of the root filesystem on the NFS server
3231 serverip - see above
3234 There are two special Environment Variables:
3236 serial# - contains hardware identification information such
3237 as type string and/or serial number
3238 ethaddr - Ethernet address
3240 These variables can be set only once (usually during manufacturing of
3241 the board). U-Boot refuses to delete or overwrite these variables
3242 once they have been set once.
3245 Further special Environment Variables:
3247 ver - Contains the U-Boot version string as printed
3248 with the "version" command. This variable is
3249 readonly (see CONFIG_VERSION_VARIABLE).
3252 Please note that changes to some configuration parameters may take
3253 only effect after the next boot (yes, that's just like Windoze :-).
3256 Command Line Parsing:
3257 =====================
3259 There are two different command line parsers available with U-Boot:
3260 the old "simple" one, and the much more powerful "hush" shell:
3262 Old, simple command line parser:
3263 --------------------------------
3265 - supports environment variables (through setenv / saveenv commands)
3266 - several commands on one line, separated by ';'
3267 - variable substitution using "... ${name} ..." syntax
3268 - special characters ('$', ';') can be escaped by prefixing with '\',
3270 setenv bootcmd bootm \${address}
3271 - You can also escape text by enclosing in single apostrophes, for example:
3272 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3277 - similar to Bourne shell, with control structures like
3278 if...then...else...fi, for...do...done; while...do...done,
3279 until...do...done, ...
3280 - supports environment ("global") variables (through setenv / saveenv
3281 commands) and local shell variables (through standard shell syntax
3282 "name=value"); only environment variables can be used with "run"
3288 (1) If a command line (or an environment variable executed by a "run"
3289 command) contains several commands separated by semicolon, and
3290 one of these commands fails, then the remaining commands will be
3293 (2) If you execute several variables with one call to run (i. e.
3294 calling run with a list of variables as arguments), any failing
3295 command will cause "run" to terminate, i. e. the remaining
3296 variables are not executed.
3298 Note for Redundant Ethernet Interfaces:
3299 =======================================
3301 Some boards come with redundant Ethernet interfaces; U-Boot supports
3302 such configurations and is capable of automatic selection of a
3303 "working" interface when needed. MAC assignment works as follows:
3305 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3306 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3307 "eth1addr" (=>eth1), "eth2addr", ...
3309 If the network interface stores some valid MAC address (for instance
3310 in SROM), this is used as default address if there is NO correspon-
3311 ding setting in the environment; if the corresponding environment
3312 variable is set, this overrides the settings in the card; that means:
3314 o If the SROM has a valid MAC address, and there is no address in the
3315 environment, the SROM's address is used.
3317 o If there is no valid address in the SROM, and a definition in the
3318 environment exists, then the value from the environment variable is
3321 o If both the SROM and the environment contain a MAC address, and
3322 both addresses are the same, this MAC address is used.
3324 o If both the SROM and the environment contain a MAC address, and the
3325 addresses differ, the value from the environment is used and a
3328 o If neither SROM nor the environment contain a MAC address, an error
3331 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3332 will be programmed into hardware as part of the initialization process. This
3333 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3334 The naming convention is as follows:
3335 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3340 U-Boot is capable of booting (and performing other auxiliary operations on)
3341 images in two formats:
3343 New uImage format (FIT)
3344 -----------------------
3346 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3347 to Flattened Device Tree). It allows the use of images with multiple
3348 components (several kernels, ramdisks, etc.), with contents protected by
3349 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3355 Old image format is based on binary files which can be basically anything,
3356 preceded by a special header; see the definitions in include/image.h for
3357 details; basically, the header defines the following image properties:
3359 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3360 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3361 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3362 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3364 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3365 IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3366 Currently supported: ARM, AVR32, Intel x86, MIPS, Nios II, PowerPC).
3367 * Compression Type (uncompressed, gzip, bzip2)
3373 The header is marked by a special Magic Number, and both the header
3374 and the data portions of the image are secured against corruption by
3381 Although U-Boot should support any OS or standalone application
3382 easily, the main focus has always been on Linux during the design of
3385 U-Boot includes many features that so far have been part of some
3386 special "boot loader" code within the Linux kernel. Also, any
3387 "initrd" images to be used are no longer part of one big Linux image;
3388 instead, kernel and "initrd" are separate images. This implementation
3389 serves several purposes:
3391 - the same features can be used for other OS or standalone
3392 applications (for instance: using compressed images to reduce the
3393 Flash memory footprint)
3395 - it becomes much easier to port new Linux kernel versions because
3396 lots of low-level, hardware dependent stuff are done by U-Boot
3398 - the same Linux kernel image can now be used with different "initrd"
3399 images; of course this also means that different kernel images can
3400 be run with the same "initrd". This makes testing easier (you don't
3401 have to build a new "zImage.initrd" Linux image when you just
3402 change a file in your "initrd"). Also, a field-upgrade of the
3403 software is easier now.
3409 Porting Linux to U-Boot based systems:
3410 ---------------------------------------
3412 U-Boot cannot save you from doing all the necessary modifications to
3413 configure the Linux device drivers for use with your target hardware
3414 (no, we don't intend to provide a full virtual machine interface to
3417 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3419 Just make sure your machine specific header file (for instance
3420 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3421 Information structure as we define in include/asm-<arch>/u-boot.h,
3422 and make sure that your definition of IMAP_ADDR uses the same value
3423 as your U-Boot configuration in CONFIG_SYS_IMMR.
3426 Configuring the Linux kernel:
3427 -----------------------------
3429 No specific requirements for U-Boot. Make sure you have some root
3430 device (initial ramdisk, NFS) for your target system.
3433 Building a Linux Image:
3434 -----------------------
3436 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3437 not used. If you use recent kernel source, a new build target
3438 "uImage" will exist which automatically builds an image usable by
3439 U-Boot. Most older kernels also have support for a "pImage" target,
3440 which was introduced for our predecessor project PPCBoot and uses a
3441 100% compatible format.
3450 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3451 encapsulate a compressed Linux kernel image with header information,
3452 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3454 * build a standard "vmlinux" kernel image (in ELF binary format):
3456 * convert the kernel into a raw binary image:
3458 ${CROSS_COMPILE}-objcopy -O binary \
3459 -R .note -R .comment \
3460 -S vmlinux linux.bin
3462 * compress the binary image:
3466 * package compressed binary image for U-Boot:
3468 mkimage -A ppc -O linux -T kernel -C gzip \
3469 -a 0 -e 0 -n "Linux Kernel Image" \
3470 -d linux.bin.gz uImage
3473 The "mkimage" tool can also be used to create ramdisk images for use
3474 with U-Boot, either separated from the Linux kernel image, or
3475 combined into one file. "mkimage" encapsulates the images with a 64
3476 byte header containing information about target architecture,
3477 operating system, image type, compression method, entry points, time
3478 stamp, CRC32 checksums, etc.
3480 "mkimage" can be called in two ways: to verify existing images and
3481 print the header information, or to build new images.
3483 In the first form (with "-l" option) mkimage lists the information
3484 contained in the header of an existing U-Boot image; this includes
3485 checksum verification:
3487 tools/mkimage -l image
3488 -l ==> list image header information
3490 The second form (with "-d" option) is used to build a U-Boot image
3491 from a "data file" which is used as image payload:
3493 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3494 -n name -d data_file image
3495 -A ==> set architecture to 'arch'
3496 -O ==> set operating system to 'os'
3497 -T ==> set image type to 'type'
3498 -C ==> set compression type 'comp'
3499 -a ==> set load address to 'addr' (hex)
3500 -e ==> set entry point to 'ep' (hex)
3501 -n ==> set image name to 'name'
3502 -d ==> use image data from 'datafile'
3504 Right now, all Linux kernels for PowerPC systems use the same load
3505 address (0x00000000), but the entry point address depends on the
3508 - 2.2.x kernels have the entry point at 0x0000000C,
3509 - 2.3.x and later kernels have the entry point at 0x00000000.
3511 So a typical call to build a U-Boot image would read:
3513 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3514 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3515 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3516 > examples/uImage.TQM850L
3517 Image Name: 2.4.4 kernel for TQM850L
3518 Created: Wed Jul 19 02:34:59 2000
3519 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3520 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3521 Load Address: 0x00000000
3522 Entry Point: 0x00000000
3524 To verify the contents of the image (or check for corruption):
3526 -> tools/mkimage -l examples/uImage.TQM850L
3527 Image Name: 2.4.4 kernel for TQM850L
3528 Created: Wed Jul 19 02:34:59 2000
3529 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3530 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3531 Load Address: 0x00000000
3532 Entry Point: 0x00000000
3534 NOTE: for embedded systems where boot time is critical you can trade
3535 speed for memory and install an UNCOMPRESSED image instead: this
3536 needs more space in Flash, but boots much faster since it does not
3537 need to be uncompressed:
3539 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3540 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3541 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3542 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3543 > examples/uImage.TQM850L-uncompressed
3544 Image Name: 2.4.4 kernel for TQM850L
3545 Created: Wed Jul 19 02:34:59 2000
3546 Image Type: PowerPC Linux Kernel Image (uncompressed)
3547 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3548 Load Address: 0x00000000
3549 Entry Point: 0x00000000
3552 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3553 when your kernel is intended to use an initial ramdisk:
3555 -> tools/mkimage -n 'Simple Ramdisk Image' \
3556 > -A ppc -O linux -T ramdisk -C gzip \
3557 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3558 Image Name: Simple Ramdisk Image
3559 Created: Wed Jan 12 14:01:50 2000
3560 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3561 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3562 Load Address: 0x00000000
3563 Entry Point: 0x00000000
3566 Installing a Linux Image:
3567 -------------------------
3569 To downloading a U-Boot image over the serial (console) interface,
3570 you must convert the image to S-Record format:
3572 objcopy -I binary -O srec examples/image examples/image.srec
3574 The 'objcopy' does not understand the information in the U-Boot
3575 image header, so the resulting S-Record file will be relative to
3576 address 0x00000000. To load it to a given address, you need to
3577 specify the target address as 'offset' parameter with the 'loads'
3580 Example: install the image to address 0x40100000 (which on the
3581 TQM8xxL is in the first Flash bank):
3583 => erase 40100000 401FFFFF
3589 ## Ready for S-Record download ...
3590 ~>examples/image.srec
3591 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3593 15989 15990 15991 15992
3594 [file transfer complete]
3596 ## Start Addr = 0x00000000
3599 You can check the success of the download using the 'iminfo' command;
3600 this includes a checksum verification so you can be sure no data
3601 corruption happened:
3605 ## Checking Image at 40100000 ...
3606 Image Name: 2.2.13 for initrd on TQM850L
3607 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3608 Data Size: 335725 Bytes = 327 kB = 0 MB
3609 Load Address: 00000000
3610 Entry Point: 0000000c
3611 Verifying Checksum ... OK
3617 The "bootm" command is used to boot an application that is stored in
3618 memory (RAM or Flash). In case of a Linux kernel image, the contents
3619 of the "bootargs" environment variable is passed to the kernel as
3620 parameters. You can check and modify this variable using the
3621 "printenv" and "setenv" commands:
3624 => printenv bootargs
3625 bootargs=root=/dev/ram
3627 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3629 => printenv bootargs
3630 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3633 ## Booting Linux kernel at 40020000 ...
3634 Image Name: 2.2.13 for NFS on TQM850L
3635 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3636 Data Size: 381681 Bytes = 372 kB = 0 MB
3637 Load Address: 00000000
3638 Entry Point: 0000000c
3639 Verifying Checksum ... OK
3640 Uncompressing Kernel Image ... OK
3641 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
3642 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3643 time_init: decrementer frequency = 187500000/60
3644 Calibrating delay loop... 49.77 BogoMIPS
3645 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3648 If you want to boot a Linux kernel with initial RAM disk, you pass
3649 the memory addresses of both the kernel and the initrd image (PPBCOOT
3650 format!) to the "bootm" command:
3652 => imi 40100000 40200000
3654 ## Checking Image at 40100000 ...
3655 Image Name: 2.2.13 for initrd on TQM850L
3656 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3657 Data Size: 335725 Bytes = 327 kB = 0 MB
3658 Load Address: 00000000
3659 Entry Point: 0000000c
3660 Verifying Checksum ... OK
3662 ## Checking Image at 40200000 ...
3663 Image Name: Simple Ramdisk Image
3664 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3665 Data Size: 566530 Bytes = 553 kB = 0 MB
3666 Load Address: 00000000
3667 Entry Point: 00000000
3668 Verifying Checksum ... OK
3670 => bootm 40100000 40200000
3671 ## Booting Linux kernel at 40100000 ...
3672 Image Name: 2.2.13 for initrd on TQM850L
3673 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3674 Data Size: 335725 Bytes = 327 kB = 0 MB
3675 Load Address: 00000000
3676 Entry Point: 0000000c
3677 Verifying Checksum ... OK
3678 Uncompressing Kernel Image ... OK
3679 ## Loading RAMDisk Image at 40200000 ...
3680 Image Name: Simple Ramdisk Image
3681 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3682 Data Size: 566530 Bytes = 553 kB = 0 MB
3683 Load Address: 00000000
3684 Entry Point: 00000000
3685 Verifying Checksum ... OK
3686 Loading Ramdisk ... OK
3687 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
3688 Boot arguments: root=/dev/ram
3689 time_init: decrementer frequency = 187500000/60
3690 Calibrating delay loop... 49.77 BogoMIPS
3692 RAMDISK: Compressed image found at block 0
3693 VFS: Mounted root (ext2 filesystem).
3697 Boot Linux and pass a flat device tree:
3700 First, U-Boot must be compiled with the appropriate defines. See the section
3701 titled "Linux Kernel Interface" above for a more in depth explanation. The
3702 following is an example of how to start a kernel and pass an updated
3708 oft=oftrees/mpc8540ads.dtb
3709 => tftp $oftaddr $oft
3710 Speed: 1000, full duplex
3712 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3713 Filename 'oftrees/mpc8540ads.dtb'.
3714 Load address: 0x300000
3717 Bytes transferred = 4106 (100a hex)
3718 => tftp $loadaddr $bootfile
3719 Speed: 1000, full duplex
3721 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3723 Load address: 0x200000
3724 Loading:############
3726 Bytes transferred = 1029407 (fb51f hex)
3731 => bootm $loadaddr - $oftaddr
3732 ## Booting image at 00200000 ...
3733 Image Name: Linux-2.6.17-dirty
3734 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3735 Data Size: 1029343 Bytes = 1005.2 kB
3736 Load Address: 00000000
3737 Entry Point: 00000000
3738 Verifying Checksum ... OK
3739 Uncompressing Kernel Image ... OK
3740 Booting using flat device tree at 0x300000
3741 Using MPC85xx ADS machine description
3742 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3746 More About U-Boot Image Types:
3747 ------------------------------
3749 U-Boot supports the following image types:
3751 "Standalone Programs" are directly runnable in the environment
3752 provided by U-Boot; it is expected that (if they behave
3753 well) you can continue to work in U-Boot after return from
3754 the Standalone Program.
3755 "OS Kernel Images" are usually images of some Embedded OS which
3756 will take over control completely. Usually these programs
3757 will install their own set of exception handlers, device
3758 drivers, set up the MMU, etc. - this means, that you cannot
3759 expect to re-enter U-Boot except by resetting the CPU.
3760 "RAMDisk Images" are more or less just data blocks, and their
3761 parameters (address, size) are passed to an OS kernel that is
3763 "Multi-File Images" contain several images, typically an OS
3764 (Linux) kernel image and one or more data images like
3765 RAMDisks. This construct is useful for instance when you want
3766 to boot over the network using BOOTP etc., where the boot
3767 server provides just a single image file, but you want to get
3768 for instance an OS kernel and a RAMDisk image.
3770 "Multi-File Images" start with a list of image sizes, each
3771 image size (in bytes) specified by an "uint32_t" in network
3772 byte order. This list is terminated by an "(uint32_t)0".
3773 Immediately after the terminating 0 follow the images, one by
3774 one, all aligned on "uint32_t" boundaries (size rounded up to
3775 a multiple of 4 bytes).
3777 "Firmware Images" are binary images containing firmware (like
3778 U-Boot or FPGA images) which usually will be programmed to
3781 "Script files" are command sequences that will be executed by
3782 U-Boot's command interpreter; this feature is especially
3783 useful when you configure U-Boot to use a real shell (hush)
3784 as command interpreter.
3790 One of the features of U-Boot is that you can dynamically load and
3791 run "standalone" applications, which can use some resources of
3792 U-Boot like console I/O functions or interrupt services.
3794 Two simple examples are included with the sources:
3799 'examples/hello_world.c' contains a small "Hello World" Demo
3800 application; it is automatically compiled when you build U-Boot.
3801 It's configured to run at address 0x00040004, so you can play with it
3805 ## Ready for S-Record download ...
3806 ~>examples/hello_world.srec
3807 1 2 3 4 5 6 7 8 9 10 11 ...
3808 [file transfer complete]
3810 ## Start Addr = 0x00040004
3812 => go 40004 Hello World! This is a test.
3813 ## Starting application at 0x00040004 ...
3824 Hit any key to exit ...
3826 ## Application terminated, rc = 0x0
3828 Another example, which demonstrates how to register a CPM interrupt
3829 handler with the U-Boot code, can be found in 'examples/timer.c'.
3830 Here, a CPM timer is set up to generate an interrupt every second.
3831 The interrupt service routine is trivial, just printing a '.'
3832 character, but this is just a demo program. The application can be
3833 controlled by the following keys:
3835 ? - print current values og the CPM Timer registers
3836 b - enable interrupts and start timer
3837 e - stop timer and disable interrupts
3838 q - quit application
3841 ## Ready for S-Record download ...
3842 ~>examples/timer.srec
3843 1 2 3 4 5 6 7 8 9 10 11 ...
3844 [file transfer complete]
3846 ## Start Addr = 0x00040004
3849 ## Starting application at 0x00040004 ...
3852 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3855 [q, b, e, ?] Set interval 1000000 us
3858 [q, b, e, ?] ........
3859 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3862 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3865 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3868 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3870 [q, b, e, ?] ...Stopping timer
3872 [q, b, e, ?] ## Application terminated, rc = 0x0
3878 Over time, many people have reported problems when trying to use the
3879 "minicom" terminal emulation program for serial download. I (wd)
3880 consider minicom to be broken, and recommend not to use it. Under
3881 Unix, I recommend to use C-Kermit for general purpose use (and
3882 especially for kermit binary protocol download ("loadb" command), and
3883 use "cu" for S-Record download ("loads" command).
3885 Nevertheless, if you absolutely want to use it try adding this
3886 configuration to your "File transfer protocols" section:
3888 Name Program Name U/D FullScr IO-Red. Multi
3889 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3890 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3896 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3897 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3899 Building requires a cross environment; it is known to work on
3900 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3901 need gmake since the Makefiles are not compatible with BSD make).
3902 Note that the cross-powerpc package does not install include files;
3903 attempting to build U-Boot will fail because <machine/ansi.h> is
3904 missing. This file has to be installed and patched manually:
3906 # cd /usr/pkg/cross/powerpc-netbsd/include
3908 # ln -s powerpc machine
3909 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3910 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3912 Native builds *don't* work due to incompatibilities between native
3913 and U-Boot include files.
3915 Booting assumes that (the first part of) the image booted is a
3916 stage-2 loader which in turn loads and then invokes the kernel
3917 proper. Loader sources will eventually appear in the NetBSD source
3918 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3919 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3922 Implementation Internals:
3923 =========================
3925 The following is not intended to be a complete description of every
3926 implementation detail. However, it should help to understand the
3927 inner workings of U-Boot and make it easier to port it to custom
3931 Initial Stack, Global Data:
3932 ---------------------------
3934 The implementation of U-Boot is complicated by the fact that U-Boot
3935 starts running out of ROM (flash memory), usually without access to
3936 system RAM (because the memory controller is not initialized yet).
3937 This means that we don't have writable Data or BSS segments, and BSS
3938 is not initialized as zero. To be able to get a C environment working
3939 at all, we have to allocate at least a minimal stack. Implementation
3940 options for this are defined and restricted by the CPU used: Some CPU
3941 models provide on-chip memory (like the IMMR area on MPC8xx and
3942 MPC826x processors), on others (parts of) the data cache can be
3943 locked as (mis-) used as memory, etc.
3945 Chris Hallinan posted a good summary of these issues to the
3946 U-Boot mailing list:
3948 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3949 From: "Chris Hallinan" <clh@net1plus.com>
3950 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3953 Correct me if I'm wrong, folks, but the way I understand it
3954 is this: Using DCACHE as initial RAM for Stack, etc, does not
3955 require any physical RAM backing up the cache. The cleverness
3956 is that the cache is being used as a temporary supply of
3957 necessary storage before the SDRAM controller is setup. It's
3958 beyond the scope of this list to explain the details, but you
3959 can see how this works by studying the cache architecture and
3960 operation in the architecture and processor-specific manuals.
3962 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3963 is another option for the system designer to use as an
3964 initial stack/RAM area prior to SDRAM being available. Either
3965 option should work for you. Using CS 4 should be fine if your
3966 board designers haven't used it for something that would
3967 cause you grief during the initial boot! It is frequently not
3970 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3971 with your processor/board/system design. The default value
3972 you will find in any recent u-boot distribution in
3973 walnut.h should work for you. I'd set it to a value larger
3974 than your SDRAM module. If you have a 64MB SDRAM module, set
3975 it above 400_0000. Just make sure your board has no resources
3976 that are supposed to respond to that address! That code in
3977 start.S has been around a while and should work as is when
3978 you get the config right.
3983 It is essential to remember this, since it has some impact on the C
3984 code for the initialization procedures:
3986 * Initialized global data (data segment) is read-only. Do not attempt
3989 * Do not use any uninitialized global data (or implicitely initialized
3990 as zero data - BSS segment) at all - this is undefined, initiali-
3991 zation is performed later (when relocating to RAM).
3993 * Stack space is very limited. Avoid big data buffers or things like
3996 Having only the stack as writable memory limits means we cannot use
3997 normal global data to share information beween the code. But it
3998 turned out that the implementation of U-Boot can be greatly
3999 simplified by making a global data structure (gd_t) available to all
4000 functions. We could pass a pointer to this data as argument to _all_
4001 functions, but this would bloat the code. Instead we use a feature of
4002 the GCC compiler (Global Register Variables) to share the data: we
4003 place a pointer (gd) to the global data into a register which we
4004 reserve for this purpose.
4006 When choosing a register for such a purpose we are restricted by the
4007 relevant (E)ABI specifications for the current architecture, and by
4008 GCC's implementation.
4010 For PowerPC, the following registers have specific use:
4012 R2: reserved for system use
4013 R3-R4: parameter passing and return values
4014 R5-R10: parameter passing
4015 R13: small data area pointer
4019 (U-Boot also uses R12 as internal GOT pointer. r12
4020 is a volatile register so r12 needs to be reset when
4021 going back and forth between asm and C)
4023 ==> U-Boot will use R2 to hold a pointer to the global data
4025 Note: on PPC, we could use a static initializer (since the
4026 address of the global data structure is known at compile time),
4027 but it turned out that reserving a register results in somewhat
4028 smaller code - although the code savings are not that big (on
4029 average for all boards 752 bytes for the whole U-Boot image,
4030 624 text + 127 data).
4032 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4033 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4035 ==> U-Boot will use P3 to hold a pointer to the global data
4037 On ARM, the following registers are used:
4039 R0: function argument word/integer result
4040 R1-R3: function argument word
4042 R10: stack limit (used only if stack checking if enabled)
4043 R11: argument (frame) pointer
4044 R12: temporary workspace
4047 R15: program counter
4049 ==> U-Boot will use R8 to hold a pointer to the global data
4051 On Nios II, the ABI is documented here:
4052 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4054 ==> U-Boot will use gp to hold a pointer to the global data
4056 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4057 to access small data sections, so gp is free.
4059 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4060 or current versions of GCC may "optimize" the code too much.
4065 U-Boot runs in system state and uses physical addresses, i.e. the
4066 MMU is not used either for address mapping nor for memory protection.
4068 The available memory is mapped to fixed addresses using the memory
4069 controller. In this process, a contiguous block is formed for each
4070 memory type (Flash, SDRAM, SRAM), even when it consists of several
4071 physical memory banks.
4073 U-Boot is installed in the first 128 kB of the first Flash bank (on
4074 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4075 booting and sizing and initializing DRAM, the code relocates itself
4076 to the upper end of DRAM. Immediately below the U-Boot code some
4077 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4078 configuration setting]. Below that, a structure with global Board
4079 Info data is placed, followed by the stack (growing downward).
4081 Additionally, some exception handler code is copied to the low 8 kB
4082 of DRAM (0x00000000 ... 0x00001FFF).
4084 So a typical memory configuration with 16 MB of DRAM could look like
4087 0x0000 0000 Exception Vector code
4090 0x0000 2000 Free for Application Use
4096 0x00FB FF20 Monitor Stack (Growing downward)
4097 0x00FB FFAC Board Info Data and permanent copy of global data
4098 0x00FC 0000 Malloc Arena
4101 0x00FE 0000 RAM Copy of Monitor Code
4102 ... eventually: LCD or video framebuffer
4103 ... eventually: pRAM (Protected RAM - unchanged by reset)
4104 0x00FF FFFF [End of RAM]
4107 System Initialization:
4108 ----------------------
4110 In the reset configuration, U-Boot starts at the reset entry point
4111 (on most PowerPC systems at address 0x00000100). Because of the reset
4112 configuration for CS0# this is a mirror of the onboard Flash memory.
4113 To be able to re-map memory U-Boot then jumps to its link address.
4114 To be able to implement the initialization code in C, a (small!)
4115 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4116 which provide such a feature like MPC8xx or MPC8260), or in a locked
4117 part of the data cache. After that, U-Boot initializes the CPU core,
4118 the caches and the SIU.
4120 Next, all (potentially) available memory banks are mapped using a
4121 preliminary mapping. For example, we put them on 512 MB boundaries
4122 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4123 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4124 programmed for SDRAM access. Using the temporary configuration, a
4125 simple memory test is run that determines the size of the SDRAM
4128 When there is more than one SDRAM bank, and the banks are of
4129 different size, the largest is mapped first. For equal size, the first
4130 bank (CS2#) is mapped first. The first mapping is always for address
4131 0x00000000, with any additional banks following immediately to create
4132 contiguous memory starting from 0.
4134 Then, the monitor installs itself at the upper end of the SDRAM area
4135 and allocates memory for use by malloc() and for the global Board
4136 Info data; also, the exception vector code is copied to the low RAM
4137 pages, and the final stack is set up.
4139 Only after this relocation will you have a "normal" C environment;
4140 until that you are restricted in several ways, mostly because you are
4141 running from ROM, and because the code will have to be relocated to a
4145 U-Boot Porting Guide:
4146 ----------------------
4148 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4152 int main(int argc, char *argv[])
4154 sighandler_t no_more_time;
4156 signal(SIGALRM, no_more_time);
4157 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4159 if (available_money > available_manpower) {
4160 Pay consultant to port U-Boot;
4164 Download latest U-Boot source;
4166 Subscribe to u-boot mailing list;
4169 email("Hi, I am new to U-Boot, how do I get started?");
4172 Read the README file in the top level directory;
4173 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4174 Read applicable doc/*.README;
4175 Read the source, Luke;
4176 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4179 if (available_money > toLocalCurrency ($2500))
4182 Add a lot of aggravation and time;
4184 if (a similar board exists) { /* hopefully... */
4185 cp -a board/<similar> board/<myboard>
4186 cp include/configs/<similar>.h include/configs/<myboard>.h
4188 Create your own board support subdirectory;
4189 Create your own board include/configs/<myboard>.h file;
4191 Edit new board/<myboard> files
4192 Edit new include/configs/<myboard>.h
4197 Add / modify source code;
4201 email("Hi, I am having problems...");
4203 Send patch file to the U-Boot email list;
4204 if (reasonable critiques)
4205 Incorporate improvements from email list code review;
4207 Defend code as written;
4213 void no_more_time (int sig)
4222 All contributions to U-Boot should conform to the Linux kernel
4223 coding style; see the file "Documentation/CodingStyle" and the script
4224 "scripts/Lindent" in your Linux kernel source directory. In sources
4225 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4226 spaces before parameters to function calls) is actually used.
4228 Source files originating from a different project (for example the
4229 MTD subsystem) are generally exempt from these guidelines and are not
4230 reformated to ease subsequent migration to newer versions of those
4233 Please note that U-Boot is implemented in C (and to some small parts in
4234 Assembler); no C++ is used, so please do not use C++ style comments (//)
4237 Please also stick to the following formatting rules:
4238 - remove any trailing white space
4239 - use TAB characters for indentation, not spaces
4240 - make sure NOT to use DOS '\r\n' line feeds
4241 - do not add more than 2 empty lines to source files
4242 - do not add trailing empty lines to source files
4244 Submissions which do not conform to the standards may be returned
4245 with a request to reformat the changes.
4251 Since the number of patches for U-Boot is growing, we need to
4252 establish some rules. Submissions which do not conform to these rules
4253 may be rejected, even when they contain important and valuable stuff.
4255 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4257 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4258 see http://lists.denx.de/mailman/listinfo/u-boot
4260 When you send a patch, please include the following information with
4263 * For bug fixes: a description of the bug and how your patch fixes
4264 this bug. Please try to include a way of demonstrating that the
4265 patch actually fixes something.
4267 * For new features: a description of the feature and your
4270 * A CHANGELOG entry as plaintext (separate from the patch)
4272 * For major contributions, your entry to the CREDITS file
4274 * When you add support for a new board, don't forget to add this
4275 board to the MAKEALL script, too.
4277 * If your patch adds new configuration options, don't forget to
4278 document these in the README file.
4280 * The patch itself. If you are using git (which is *strongly*
4281 recommended) you can easily generate the patch using the
4282 "git-format-patch". If you then use "git-send-email" to send it to
4283 the U-Boot mailing list, you will avoid most of the common problems
4284 with some other mail clients.
4286 If you cannot use git, use "diff -purN OLD NEW". If your version of
4287 diff does not support these options, then get the latest version of
4290 The current directory when running this command shall be the parent
4291 directory of the U-Boot source tree (i. e. please make sure that
4292 your patch includes sufficient directory information for the
4295 We prefer patches as plain text. MIME attachments are discouraged,
4296 and compressed attachments must not be used.
4298 * If one logical set of modifications affects or creates several
4299 files, all these changes shall be submitted in a SINGLE patch file.
4301 * Changesets that contain different, unrelated modifications shall be
4302 submitted as SEPARATE patches, one patch per changeset.
4307 * Before sending the patch, run the MAKEALL script on your patched
4308 source tree and make sure that no errors or warnings are reported
4309 for any of the boards.
4311 * Keep your modifications to the necessary minimum: A patch
4312 containing several unrelated changes or arbitrary reformats will be
4313 returned with a request to re-formatting / split it.
4315 * If you modify existing code, make sure that your new code does not
4316 add to the memory footprint of the code ;-) Small is beautiful!
4317 When adding new features, these should compile conditionally only
4318 (using #ifdef), and the resulting code with the new feature
4319 disabled must not need more memory than the old code without your
4322 * Remember that there is a size limit of 100 kB per message on the
4323 u-boot mailing list. Bigger patches will be moderated. If they are
4324 reasonable and not too big, they will be acknowledged. But patches
4325 bigger than the size limit should be avoided.
projects / u-boot / blob