2 # (C) Copyright 2000 - 2009
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 Starting with the release in October 2008, the names of the releases
130 were changed from numerical release numbers without deeper meaning
131 into a time stamp based numbering. Regular releases are identified by
132 names consisting of the calendar year and month of the release date.
133 Additional fields (if present) indicate release candidates or bug fix
134 releases in "stable" maintenance trees.
137 U-Boot v2009.11 - Release November 2009
138 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
139 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
145 /arch Architecture specific files
146 /arm Files generic to ARM architecture
147 /cpu CPU specific files
148 /arm720t Files specific to ARM 720 CPUs
149 /arm920t Files specific to ARM 920 CPUs
150 /at91rm9200 Files specific to Atmel AT91RM9200 CPU
151 /imx Files specific to Freescale MC9328 i.MX CPUs
152 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
153 /arm925t Files specific to ARM 925 CPUs
154 /arm926ejs Files specific to ARM 926 CPUs
155 /arm1136 Files specific to ARM 1136 CPUs
156 /ixp Files specific to Intel XScale IXP CPUs
157 /pxa Files specific to Intel XScale PXA CPUs
158 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
159 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
160 /lib Architecture specific library files
161 /avr32 Files generic to AVR32 architecture
162 /cpu CPU specific files
163 /lib Architecture specific library files
164 /blackfin Files generic to Analog Devices Blackfin architecture
165 /cpu CPU specific files
166 /lib Architecture specific library files
167 /i386 Files generic to i386 architecture
168 /cpu CPU specific files
169 /lib Architecture specific library files
170 /m68k Files generic to m68k architecture
171 /cpu CPU specific files
172 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
173 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
174 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
175 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
176 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
177 /lib Architecture specific library files
178 /microblaze Files generic to microblaze architecture
179 /cpu CPU specific files
180 /lib Architecture specific library files
181 /mips Files generic to MIPS architecture
182 /cpu CPU specific files
183 /lib Architecture specific library files
184 /nios2 Files generic to Altera NIOS2 architecture
185 /cpu CPU specific files
186 /lib Architecture specific library files
187 /powerpc Files generic to PowerPC architecture
188 /cpu CPU specific files
189 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
190 /mpc5xx Files specific to Freescale MPC5xx CPUs
191 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
192 /mpc8xx Files specific to Freescale MPC8xx CPUs
193 /mpc8220 Files specific to Freescale MPC8220 CPUs
194 /mpc824x Files specific to Freescale MPC824x CPUs
195 /mpc8260 Files specific to Freescale MPC8260 CPUs
196 /mpc85xx Files specific to Freescale MPC85xx CPUs
197 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
198 /lib Architecture specific library files
199 /sh Files generic to SH architecture
200 /cpu CPU specific files
201 /sh2 Files specific to sh2 CPUs
202 /sh3 Files specific to sh3 CPUs
203 /sh4 Files specific to sh4 CPUs
204 /lib Architecture specific library files
205 /sparc Files generic to SPARC architecture
206 /cpu CPU specific files
207 /leon2 Files specific to Gaisler LEON2 SPARC CPU
208 /leon3 Files specific to Gaisler LEON3 SPARC CPU
209 /lib Architecture specific library files
210 /api Machine/arch independent API for external apps
211 /board Board dependent files
212 /common Misc architecture independent functions
213 /disk Code for disk drive partition handling
214 /doc Documentation (don't expect too much)
215 /drivers Commonly used device drivers
216 /examples Example code for standalone applications, etc.
217 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
218 /include Header Files
219 /lib Files generic to all architectures
220 /libfdt Library files to support flattened device trees
221 /lzma Library files to support LZMA decompression
222 /lzo Library files to support LZO decompression
224 /post Power On Self Test
225 /rtc Real Time Clock drivers
226 /tools Tools to build S-Record or U-Boot images, etc.
228 Software Configuration:
229 =======================
231 Configuration is usually done using C preprocessor defines; the
232 rationale behind that is to avoid dead code whenever possible.
234 There are two classes of configuration variables:
236 * Configuration _OPTIONS_:
237 These are selectable by the user and have names beginning with
240 * Configuration _SETTINGS_:
241 These depend on the hardware etc. and should not be meddled with if
242 you don't know what you're doing; they have names beginning with
245 Later we will add a configuration tool - probably similar to or even
246 identical to what's used for the Linux kernel. Right now, we have to
247 do the configuration by hand, which means creating some symbolic
248 links and editing some configuration files. We use the TQM8xxL boards
252 Selection of Processor Architecture and Board Type:
253 ---------------------------------------------------
255 For all supported boards there are ready-to-use default
256 configurations available; just type "make <board_name>_config".
258 Example: For a TQM823L module type:
263 For the Cogent platform, you need to specify the CPU type as well;
264 e.g. "make cogent_mpc8xx_config". And also configure the cogent
265 directory according to the instructions in cogent/README.
268 Configuration Options:
269 ----------------------
271 Configuration depends on the combination of board and CPU type; all
272 such information is kept in a configuration file
273 "include/configs/<board_name>.h".
275 Example: For a TQM823L module, all configuration settings are in
276 "include/configs/TQM823L.h".
279 Many of the options are named exactly as the corresponding Linux
280 kernel configuration options. The intention is to make it easier to
281 build a config tool - later.
284 The following options need to be configured:
286 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
288 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
290 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
291 Define exactly one, e.g. CONFIG_ATSTK1002
293 - CPU Module Type: (if CONFIG_COGENT is defined)
294 Define exactly one of
296 --- FIXME --- not tested yet:
297 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
298 CONFIG_CMA287_23, CONFIG_CMA287_50
300 - Motherboard Type: (if CONFIG_COGENT is defined)
301 Define exactly one of
302 CONFIG_CMA101, CONFIG_CMA102
304 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
305 Define one or more of
308 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
309 Define one or more of
310 CONFIG_LCD_HEARTBEAT - update a character position on
311 the LCD display every second with
314 - Board flavour: (if CONFIG_MPC8260ADS is defined)
317 CONFIG_SYS_8260ADS - original MPC8260ADS
318 CONFIG_SYS_8266ADS - MPC8266ADS
319 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
320 CONFIG_SYS_8272ADS - MPC8272ADS
322 - Marvell Family Member
323 CONFIG_SYS_MVFS - define it if you want to enable
324 multiple fs option at one time
325 for marvell soc family
327 - MPC824X Family Member (if CONFIG_MPC824X is defined)
328 Define exactly one of
329 CONFIG_MPC8240, CONFIG_MPC8245
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
359 - Intel Monahans options:
360 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
362 Defines the Monahans run mode to oscillator
363 ratio. Valid values are 8, 16, 24, 31. The core
364 frequency is this value multiplied by 13 MHz.
366 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
368 Defines the Monahans turbo mode to oscillator
369 ratio. Valid values are 1 (default if undefined) and
370 2. The core frequency as calculated above is multiplied
373 - Linux Kernel Interface:
376 U-Boot stores all clock information in Hz
377 internally. For binary compatibility with older Linux
378 kernels (which expect the clocks passed in the
379 bd_info data to be in MHz) the environment variable
380 "clocks_in_mhz" can be defined so that U-Boot
381 converts clock data to MHZ before passing it to the
383 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
384 "clocks_in_mhz=1" is automatically included in the
387 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
389 When transferring memsize parameter to linux, some versions
390 expect it to be in bytes, others in MB.
391 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
395 New kernel versions are expecting firmware settings to be
396 passed using flattened device trees (based on open firmware
400 * New libfdt-based support
401 * Adds the "fdt" command
402 * The bootm command automatically updates the fdt
404 OF_CPU - The proper name of the cpus node (only required for
405 MPC512X and MPC5xxx based boards).
406 OF_SOC - The proper name of the soc node (only required for
407 MPC512X and MPC5xxx based boards).
408 OF_TBCLK - The timebase frequency.
409 OF_STDOUT_PATH - The path to the console device
411 boards with QUICC Engines require OF_QE to set UCC MAC
414 CONFIG_OF_BOARD_SETUP
416 Board code has addition modification that it wants to make
417 to the flat device tree before handing it off to the kernel
421 This define fills in the correct boot CPU in the boot
422 param header, the default value is zero if undefined.
426 U-Boot can detect if an IDE device is present or not.
427 If not, and this new config option is activated, U-Boot
428 removes the ATA node from the DTS before booting Linux,
429 so the Linux IDE driver does not probe the device and
430 crash. This is needed for buggy hardware (uc101) where
431 no pull down resistor is connected to the signal IDE5V_DD7.
433 - vxWorks boot parameters:
435 bootvx constructs a valid bootline using the following
436 environments variables: bootfile, ipaddr, serverip, hostname.
437 It loads the vxWorks image pointed bootfile.
439 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
440 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
441 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
442 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
444 CONFIG_SYS_VXWORKS_ADD_PARAMS
446 Add it at the end of the bootline. E.g "u=username pw=secret"
448 Note: If a "bootargs" environment is defined, it will overwride
449 the defaults discussed just above.
454 Define this if you want support for Amba PrimeCell PL010 UARTs.
458 Define this if you want support for Amba PrimeCell PL011 UARTs.
462 If you have Amba PrimeCell PL011 UARTs, set this variable to
463 the clock speed of the UARTs.
467 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
468 define this to a list of base addresses for each (supported)
469 port. See e.g. include/configs/versatile.h
473 Depending on board, define exactly one serial port
474 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
475 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
476 console by defining CONFIG_8xx_CONS_NONE
478 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
479 port routines must be defined elsewhere
480 (i.e. serial_init(), serial_getc(), ...)
483 Enables console device for a color framebuffer. Needs following
484 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
485 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
487 VIDEO_HW_RECTFILL graphic chip supports
490 VIDEO_HW_BITBLT graphic chip supports
491 bit-blit (cf. smiLynxEM)
492 VIDEO_VISIBLE_COLS visible pixel columns
494 VIDEO_VISIBLE_ROWS visible pixel rows
495 VIDEO_PIXEL_SIZE bytes per pixel
496 VIDEO_DATA_FORMAT graphic data format
497 (0-5, cf. cfb_console.c)
498 VIDEO_FB_ADRS framebuffer address
499 VIDEO_KBD_INIT_FCT keyboard int fct
500 (i.e. i8042_kbd_init())
501 VIDEO_TSTC_FCT test char fct
503 VIDEO_GETC_FCT get char fct
505 CONFIG_CONSOLE_CURSOR cursor drawing on/off
506 (requires blink timer
508 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
509 CONFIG_CONSOLE_TIME display time/date info in
511 (requires CONFIG_CMD_DATE)
512 CONFIG_VIDEO_LOGO display Linux logo in
514 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
515 linux_logo.h for logo.
516 Requires CONFIG_VIDEO_LOGO
517 CONFIG_CONSOLE_EXTRA_INFO
518 additional board info beside
521 When CONFIG_CFB_CONSOLE is defined, video console is
522 default i/o. Serial console can be forced with
523 environment 'console=serial'.
525 When CONFIG_SILENT_CONSOLE is defined, all console
526 messages (by U-Boot and Linux!) can be silenced with
527 the "silent" environment variable. See
528 doc/README.silent for more information.
531 CONFIG_BAUDRATE - in bps
532 Select one of the baudrates listed in
533 CONFIG_SYS_BAUDRATE_TABLE, see below.
534 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
536 - Console Rx buffer length
537 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
538 the maximum receive buffer length for the SMC.
539 This option is actual only for 82xx and 8xx possible.
540 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
541 must be defined, to setup the maximum idle timeout for
544 - Boot Delay: CONFIG_BOOTDELAY - in seconds
545 Delay before automatically booting the default image;
546 set to -1 to disable autoboot.
548 See doc/README.autoboot for these options that
549 work with CONFIG_BOOTDELAY. None are required.
550 CONFIG_BOOT_RETRY_TIME
551 CONFIG_BOOT_RETRY_MIN
552 CONFIG_AUTOBOOT_KEYED
553 CONFIG_AUTOBOOT_PROMPT
554 CONFIG_AUTOBOOT_DELAY_STR
555 CONFIG_AUTOBOOT_STOP_STR
556 CONFIG_AUTOBOOT_DELAY_STR2
557 CONFIG_AUTOBOOT_STOP_STR2
558 CONFIG_ZERO_BOOTDELAY_CHECK
559 CONFIG_RESET_TO_RETRY
563 Only needed when CONFIG_BOOTDELAY is enabled;
564 define a command string that is automatically executed
565 when no character is read on the console interface
566 within "Boot Delay" after reset.
569 This can be used to pass arguments to the bootm
570 command. The value of CONFIG_BOOTARGS goes into the
571 environment value "bootargs".
573 CONFIG_RAMBOOT and CONFIG_NFSBOOT
574 The value of these goes into the environment as
575 "ramboot" and "nfsboot" respectively, and can be used
576 as a convenience, when switching between booting from
582 When this option is #defined, the existence of the
583 environment variable "preboot" will be checked
584 immediately before starting the CONFIG_BOOTDELAY
585 countdown and/or running the auto-boot command resp.
586 entering interactive mode.
588 This feature is especially useful when "preboot" is
589 automatically generated or modified. For an example
590 see the LWMON board specific code: here "preboot" is
591 modified when the user holds down a certain
592 combination of keys on the (special) keyboard when
595 - Serial Download Echo Mode:
597 If defined to 1, all characters received during a
598 serial download (using the "loads" command) are
599 echoed back. This might be needed by some terminal
600 emulations (like "cu"), but may as well just take
601 time on others. This setting #define's the initial
602 value of the "loads_echo" environment variable.
604 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
606 Select one of the baudrates listed in
607 CONFIG_SYS_BAUDRATE_TABLE, see below.
610 Monitor commands can be included or excluded
611 from the build by using the #include files
612 "config_cmd_all.h" and #undef'ing unwanted
613 commands, or using "config_cmd_default.h"
614 and augmenting with additional #define's
617 The default command configuration includes all commands
618 except those marked below with a "*".
620 CONFIG_CMD_ASKENV * ask for env variable
621 CONFIG_CMD_BDI bdinfo
622 CONFIG_CMD_BEDBUG * Include BedBug Debugger
623 CONFIG_CMD_BMP * BMP support
624 CONFIG_CMD_BSP * Board specific commands
625 CONFIG_CMD_BOOTD bootd
626 CONFIG_CMD_CACHE * icache, dcache
627 CONFIG_CMD_CONSOLE coninfo
628 CONFIG_CMD_DATE * support for RTC, date/time...
629 CONFIG_CMD_DHCP * DHCP support
630 CONFIG_CMD_DIAG * Diagnostics
631 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
632 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
633 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
634 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
635 CONFIG_CMD_DTT * Digital Therm and Thermostat
636 CONFIG_CMD_ECHO echo arguments
637 CONFIG_CMD_EDITENV edit env variable
638 CONFIG_CMD_EEPROM * EEPROM read/write support
639 CONFIG_CMD_ELF * bootelf, bootvx
640 CONFIG_CMD_SAVEENV saveenv
641 CONFIG_CMD_FDC * Floppy Disk Support
642 CONFIG_CMD_FAT * FAT partition support
643 CONFIG_CMD_FDOS * Dos diskette Support
644 CONFIG_CMD_FLASH flinfo, erase, protect
645 CONFIG_CMD_FPGA FPGA device initialization support
646 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
647 CONFIG_CMD_I2C * I2C serial bus support
648 CONFIG_CMD_IDE * IDE harddisk support
649 CONFIG_CMD_IMI iminfo
650 CONFIG_CMD_IMLS List all found images
651 CONFIG_CMD_IMMAP * IMMR dump support
652 CONFIG_CMD_IRQ * irqinfo
653 CONFIG_CMD_ITEST Integer/string test of 2 values
654 CONFIG_CMD_JFFS2 * JFFS2 Support
655 CONFIG_CMD_KGDB * kgdb
656 CONFIG_CMD_LOADB loadb
657 CONFIG_CMD_LOADS loads
658 CONFIG_CMD_MD5SUM print md5 message digest
659 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
660 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
662 CONFIG_CMD_MISC Misc functions like sleep etc
663 CONFIG_CMD_MMC * MMC memory mapped support
664 CONFIG_CMD_MII * MII utility commands
665 CONFIG_CMD_MTDPARTS * MTD partition support
666 CONFIG_CMD_NAND * NAND support
667 CONFIG_CMD_NET bootp, tftpboot, rarpboot
668 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
669 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
670 CONFIG_CMD_PCI * pciinfo
671 CONFIG_CMD_PCMCIA * PCMCIA support
672 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
674 CONFIG_CMD_PORTIO * Port I/O
675 CONFIG_CMD_REGINFO * Register dump
676 CONFIG_CMD_RUN run command in env variable
677 CONFIG_CMD_SAVES * save S record dump
678 CONFIG_CMD_SCSI * SCSI Support
679 CONFIG_CMD_SDRAM * print SDRAM configuration information
680 (requires CONFIG_CMD_I2C)
681 CONFIG_CMD_SETGETDCR Support for DCR Register access
683 CONFIG_CMD_SHA1SUM print sha1 memory digest
684 (requires CONFIG_CMD_MEMORY)
685 CONFIG_CMD_SOURCE "source" command Support
686 CONFIG_CMD_SPI * SPI serial bus support
687 CONFIG_CMD_USB * USB support
688 CONFIG_CMD_VFD * VFD support (TRAB)
689 CONFIG_CMD_CDP * Cisco Discover Protocol support
690 CONFIG_CMD_FSL * Microblaze FSL support
693 EXAMPLE: If you want all functions except of network
694 support you can write:
696 #include "config_cmd_all.h"
697 #undef CONFIG_CMD_NET
700 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
702 Note: Don't enable the "icache" and "dcache" commands
703 (configuration option CONFIG_CMD_CACHE) unless you know
704 what you (and your U-Boot users) are doing. Data
705 cache cannot be enabled on systems like the 8xx or
706 8260 (where accesses to the IMMR region must be
707 uncached), and it cannot be disabled on all other
708 systems where we (mis-) use the data cache to hold an
709 initial stack and some data.
712 XXX - this list needs to get updated!
716 If this variable is defined, it enables watchdog
717 support. There must be support in the platform specific
718 code for a watchdog. For the 8xx and 8260 CPUs, the
719 SIU Watchdog feature is enabled in the SYPCR
723 CONFIG_VERSION_VARIABLE
724 If this variable is defined, an environment variable
725 named "ver" is created by U-Boot showing the U-Boot
726 version as printed by the "version" command.
727 This variable is readonly.
731 When CONFIG_CMD_DATE is selected, the type of the RTC
732 has to be selected, too. Define exactly one of the
735 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
736 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
737 CONFIG_RTC_MC13783 - use MC13783 RTC
738 CONFIG_RTC_MC146818 - use MC146818 RTC
739 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
740 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
741 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
742 CONFIG_RTC_DS164x - use Dallas DS164x RTC
743 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
744 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
745 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
747 Note that if the RTC uses I2C, then the I2C interface
748 must also be configured. See I2C Support, below.
751 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
752 CONFIG_PCA953X_INFO - enable pca953x info command
754 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
755 chip-ngpio pairs that tell the PCA953X driver the number of
756 pins supported by a particular chip.
758 Note that if the GPIO device uses I2C, then the I2C interface
759 must also be configured. See I2C Support, below.
763 When CONFIG_TIMESTAMP is selected, the timestamp
764 (date and time) of an image is printed by image
765 commands like bootm or iminfo. This option is
766 automatically enabled when you select CONFIG_CMD_DATE .
769 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
770 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
772 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
773 CONFIG_CMD_SCSI) you must configure support for at
774 least one partition type as well.
777 CONFIG_IDE_RESET_ROUTINE - this is defined in several
778 board configurations files but used nowhere!
780 CONFIG_IDE_RESET - is this is defined, IDE Reset will
781 be performed by calling the function
782 ide_set_reset(int reset)
783 which has to be defined in a board specific file
788 Set this to enable ATAPI support.
793 Set this to enable support for disks larger than 137GB
794 Also look at CONFIG_SYS_64BIT_LBA.
795 Whithout these , LBA48 support uses 32bit variables and will 'only'
796 support disks up to 2.1TB.
798 CONFIG_SYS_64BIT_LBA:
799 When enabled, makes the IDE subsystem use 64bit sector addresses.
803 At the moment only there is only support for the
804 SYM53C8XX SCSI controller; define
805 CONFIG_SCSI_SYM53C8XX to enable it.
807 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
808 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
809 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
810 maximum numbers of LUNs, SCSI ID's and target
812 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
814 - NETWORK Support (PCI):
816 Support for Intel 8254x gigabit chips.
818 CONFIG_E1000_FALLBACK_MAC
819 default MAC for empty EEPROM after production.
822 Support for Intel 82557/82559/82559ER chips.
823 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
824 write routine for first time initialisation.
827 Support for Digital 2114x chips.
828 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
829 modem chip initialisation (KS8761/QS6611).
832 Support for National dp83815 chips.
835 Support for National dp8382[01] gigabit chips.
837 - NETWORK Support (other):
839 CONFIG_DRIVER_AT91EMAC
840 Support for AT91RM9200 EMAC.
843 Define this to use reduced MII inteface
845 CONFIG_DRIVER_AT91EMAC_QUIET
846 If this defined, the driver is quiet.
847 The driver doen't show link status messages.
849 CONFIG_DRIVER_LAN91C96
850 Support for SMSC's LAN91C96 chips.
853 Define this to hold the physical address
854 of the LAN91C96's I/O space
856 CONFIG_LAN91C96_USE_32_BIT
857 Define this to enable 32 bit addressing
859 CONFIG_DRIVER_SMC91111
860 Support for SMSC's LAN91C111 chip
863 Define this to hold the physical address
864 of the device (I/O space)
866 CONFIG_SMC_USE_32_BIT
867 Define this if data bus is 32 bits
869 CONFIG_SMC_USE_IOFUNCS
870 Define this to use i/o functions instead of macros
871 (some hardware wont work with macros)
874 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
876 CONFIG_FTGMAC100_EGIGA
877 Define this to use GE link update with gigabit PHY.
878 Define this if FTGMAC100 is connected to gigabit PHY.
879 If your system has 10/100 PHY only, it might not occur
880 wrong behavior. Because PHY usually return timeout or
881 useless data when polling gigabit status and gigabit
882 control registers. This behavior won't affect the
883 correctnessof 10/100 link speed update.
886 Support for SMSC's LAN911x and LAN921x chips
889 Define this to hold the physical address
890 of the device (I/O space)
892 CONFIG_SMC911X_32_BIT
893 Define this if data bus is 32 bits
895 CONFIG_SMC911X_16_BIT
896 Define this if data bus is 16 bits. If your processor
897 automatically converts one 32 bit word to two 16 bit
898 words you may also try CONFIG_SMC911X_32_BIT.
901 Support for Renesas on-chip Ethernet controller
903 CONFIG_SH_ETHER_USE_PORT
904 Define the number of ports to be used
906 CONFIG_SH_ETHER_PHY_ADDR
907 Define the ETH PHY's address
909 CONFIG_SH_ETHER_CACHE_WRITEBACK
910 If this option is set, the driver enables cache flush.
913 At the moment only the UHCI host controller is
914 supported (PIP405, MIP405, MPC5200); define
915 CONFIG_USB_UHCI to enable it.
916 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
917 and define CONFIG_USB_STORAGE to enable the USB
920 Supported are USB Keyboards and USB Floppy drives
922 MPC5200 USB requires additional defines:
924 for 528 MHz Clock: 0x0001bbbb
928 for differential drivers: 0x00001000
929 for single ended drivers: 0x00005000
930 for differential drivers on PSC3: 0x00000100
931 for single ended drivers on PSC3: 0x00004100
932 CONFIG_SYS_USB_EVENT_POLL
933 May be defined to allow interrupt polling
934 instead of using asynchronous interrupts
937 Define the below if you wish to use the USB console.
938 Once firmware is rebuilt from a serial console issue the
939 command "setenv stdin usbtty; setenv stdout usbtty" and
940 attach your USB cable. The Unix command "dmesg" should print
941 it has found a new device. The environment variable usbtty
942 can be set to gserial or cdc_acm to enable your device to
943 appear to a USB host as a Linux gserial device or a
944 Common Device Class Abstract Control Model serial device.
945 If you select usbtty = gserial you should be able to enumerate
947 # modprobe usbserial vendor=0xVendorID product=0xProductID
948 else if using cdc_acm, simply setting the environment
949 variable usbtty to be cdc_acm should suffice. The following
950 might be defined in YourBoardName.h
953 Define this to build a UDC device
956 Define this to have a tty type of device available to
957 talk to the UDC device
959 CONFIG_SYS_CONSOLE_IS_IN_ENV
960 Define this if you want stdin, stdout &/or stderr to
964 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
965 Derive USB clock from external clock "blah"
966 - CONFIG_SYS_USB_EXTC_CLK 0x02
968 CONFIG_SYS_USB_BRG_CLK 0xBLAH
969 Derive USB clock from brgclk
970 - CONFIG_SYS_USB_BRG_CLK 0x04
972 If you have a USB-IF assigned VendorID then you may wish to
973 define your own vendor specific values either in BoardName.h
974 or directly in usbd_vendor_info.h. If you don't define
975 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
976 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
977 should pretend to be a Linux device to it's target host.
979 CONFIG_USBD_MANUFACTURER
980 Define this string as the name of your company for
981 - CONFIG_USBD_MANUFACTURER "my company"
983 CONFIG_USBD_PRODUCT_NAME
984 Define this string as the name of your product
985 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
988 Define this as your assigned Vendor ID from the USB
989 Implementors Forum. This *must* be a genuine Vendor ID
990 to avoid polluting the USB namespace.
991 - CONFIG_USBD_VENDORID 0xFFFF
993 CONFIG_USBD_PRODUCTID
994 Define this as the unique Product ID
996 - CONFIG_USBD_PRODUCTID 0xFFFF
1000 The MMC controller on the Intel PXA is supported. To
1001 enable this define CONFIG_MMC. The MMC can be
1002 accessed from the boot prompt by mapping the device
1003 to physical memory similar to flash. Command line is
1004 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1005 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1007 - Journaling Flash filesystem support:
1008 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1009 CONFIG_JFFS2_NAND_DEV
1010 Define these for a default partition on a NAND device
1012 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1013 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1014 Define these for a default partition on a NOR device
1016 CONFIG_SYS_JFFS_CUSTOM_PART
1017 Define this to create an own partition. You have to provide a
1018 function struct part_info* jffs2_part_info(int part_num)
1020 If you define only one JFFS2 partition you may also want to
1021 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1022 to disable the command chpart. This is the default when you
1023 have not defined a custom partition
1028 Define this to enable standard (PC-Style) keyboard
1032 Standard PC keyboard driver with US (is default) and
1033 GERMAN key layout (switch via environment 'keymap=de') support.
1034 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1035 for cfb_console. Supports cursor blinking.
1040 Define this to enable video support (for output to
1043 CONFIG_VIDEO_CT69000
1045 Enable Chips & Technologies 69000 Video chip
1047 CONFIG_VIDEO_SMI_LYNXEM
1048 Enable Silicon Motion SMI 712/710/810 Video chip. The
1049 video output is selected via environment 'videoout'
1050 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1053 For the CT69000 and SMI_LYNXEM drivers, videomode is
1054 selected via environment 'videomode'. Two different ways
1056 - "videomode=num" 'num' is a standard LiLo mode numbers.
1057 Following standard modes are supported (* is default):
1059 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1060 -------------+---------------------------------------------
1061 8 bits | 0x301* 0x303 0x305 0x161 0x307
1062 15 bits | 0x310 0x313 0x316 0x162 0x319
1063 16 bits | 0x311 0x314 0x317 0x163 0x31A
1064 24 bits | 0x312 0x315 0x318 ? 0x31B
1065 -------------+---------------------------------------------
1066 (i.e. setenv videomode 317; saveenv; reset;)
1068 - "videomode=bootargs" all the video parameters are parsed
1069 from the bootargs. (See drivers/video/videomodes.c)
1072 CONFIG_VIDEO_SED13806
1073 Enable Epson SED13806 driver. This driver supports 8bpp
1074 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1075 or CONFIG_VIDEO_SED13806_16BPP
1080 Define this to enable a custom keyboard support.
1081 This simply calls drv_keyboard_init() which must be
1082 defined in your board-specific files.
1083 The only board using this so far is RBC823.
1085 - LCD Support: CONFIG_LCD
1087 Define this to enable LCD support (for output to LCD
1088 display); also select one of the supported displays
1089 by defining one of these:
1093 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1095 CONFIG_NEC_NL6448AC33:
1097 NEC NL6448AC33-18. Active, color, single scan.
1099 CONFIG_NEC_NL6448BC20
1101 NEC NL6448BC20-08. 6.5", 640x480.
1102 Active, color, single scan.
1104 CONFIG_NEC_NL6448BC33_54
1106 NEC NL6448BC33-54. 10.4", 640x480.
1107 Active, color, single scan.
1111 Sharp 320x240. Active, color, single scan.
1112 It isn't 16x9, and I am not sure what it is.
1114 CONFIG_SHARP_LQ64D341
1116 Sharp LQ64D341 display, 640x480.
1117 Active, color, single scan.
1121 HLD1045 display, 640x480.
1122 Active, color, single scan.
1126 Optrex CBL50840-2 NF-FW 99 22 M5
1128 Hitachi LMG6912RPFC-00T
1132 320x240. Black & white.
1134 Normally display is black on white background; define
1135 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1137 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1139 If this option is set, the environment is checked for
1140 a variable "splashimage". If found, the usual display
1141 of logo, copyright and system information on the LCD
1142 is suppressed and the BMP image at the address
1143 specified in "splashimage" is loaded instead. The
1144 console is redirected to the "nulldev", too. This
1145 allows for a "silent" boot where a splash screen is
1146 loaded very quickly after power-on.
1148 CONFIG_SPLASH_SCREEN_ALIGN
1150 If this option is set the splash image can be freely positioned
1151 on the screen. Environment variable "splashpos" specifies the
1152 position as "x,y". If a positive number is given it is used as
1153 number of pixel from left/top. If a negative number is given it
1154 is used as number of pixel from right/bottom. You can also
1155 specify 'm' for centering the image.
1158 setenv splashpos m,m
1159 => image at center of screen
1161 setenv splashpos 30,20
1162 => image at x = 30 and y = 20
1164 setenv splashpos -10,m
1165 => vertically centered image
1166 at x = dspWidth - bmpWidth - 9
1168 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1170 If this option is set, additionally to standard BMP
1171 images, gzipped BMP images can be displayed via the
1172 splashscreen support or the bmp command.
1174 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1176 If this option is set, 8-bit RLE compressed BMP images
1177 can be displayed via the splashscreen support or the
1180 - Compression support:
1183 If this option is set, support for bzip2 compressed
1184 images is included. If not, only uncompressed and gzip
1185 compressed images are supported.
1187 NOTE: the bzip2 algorithm requires a lot of RAM, so
1188 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1193 If this option is set, support for lzma compressed
1196 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1197 requires an amount of dynamic memory that is given by the
1200 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1202 Where lc and lp stand for, respectively, Literal context bits
1203 and Literal pos bits.
1205 This value is upper-bounded by 14MB in the worst case. Anyway,
1206 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1207 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1208 a very small buffer.
1210 Use the lzmainfo tool to determinate the lc and lp values and
1211 then calculate the amount of needed dynamic memory (ensuring
1212 the appropriate CONFIG_SYS_MALLOC_LEN value).
1217 The address of PHY on MII bus.
1219 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1221 The clock frequency of the MII bus
1225 If this option is set, support for speed/duplex
1226 detection of gigabit PHY is included.
1228 CONFIG_PHY_RESET_DELAY
1230 Some PHY like Intel LXT971A need extra delay after
1231 reset before any MII register access is possible.
1232 For such PHY, set this option to the usec delay
1233 required. (minimum 300usec for LXT971A)
1235 CONFIG_PHY_CMD_DELAY (ppc4xx)
1237 Some PHY like Intel LXT971A need extra delay after
1238 command issued before MII status register can be read
1248 Define a default value for Ethernet address to use
1249 for the respective Ethernet interface, in case this
1250 is not determined automatically.
1255 Define a default value for the IP address to use for
1256 the default Ethernet interface, in case this is not
1257 determined through e.g. bootp.
1259 - Server IP address:
1262 Defines a default value for the IP address of a TFTP
1263 server to contact when using the "tftboot" command.
1265 CONFIG_KEEP_SERVERADDR
1267 Keeps the server's MAC address, in the env 'serveraddr'
1268 for passing to bootargs (like Linux's netconsole option)
1270 - Multicast TFTP Mode:
1273 Defines whether you want to support multicast TFTP as per
1274 rfc-2090; for example to work with atftp. Lets lots of targets
1275 tftp down the same boot image concurrently. Note: the Ethernet
1276 driver in use must provide a function: mcast() to join/leave a
1279 CONFIG_BOOTP_RANDOM_DELAY
1280 - BOOTP Recovery Mode:
1281 CONFIG_BOOTP_RANDOM_DELAY
1283 If you have many targets in a network that try to
1284 boot using BOOTP, you may want to avoid that all
1285 systems send out BOOTP requests at precisely the same
1286 moment (which would happen for instance at recovery
1287 from a power failure, when all systems will try to
1288 boot, thus flooding the BOOTP server. Defining
1289 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1290 inserted before sending out BOOTP requests. The
1291 following delays are inserted then:
1293 1st BOOTP request: delay 0 ... 1 sec
1294 2nd BOOTP request: delay 0 ... 2 sec
1295 3rd BOOTP request: delay 0 ... 4 sec
1297 BOOTP requests: delay 0 ... 8 sec
1299 - DHCP Advanced Options:
1300 You can fine tune the DHCP functionality by defining
1301 CONFIG_BOOTP_* symbols:
1303 CONFIG_BOOTP_SUBNETMASK
1304 CONFIG_BOOTP_GATEWAY
1305 CONFIG_BOOTP_HOSTNAME
1306 CONFIG_BOOTP_NISDOMAIN
1307 CONFIG_BOOTP_BOOTPATH
1308 CONFIG_BOOTP_BOOTFILESIZE
1311 CONFIG_BOOTP_SEND_HOSTNAME
1312 CONFIG_BOOTP_NTPSERVER
1313 CONFIG_BOOTP_TIMEOFFSET
1314 CONFIG_BOOTP_VENDOREX
1316 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1317 environment variable, not the BOOTP server.
1319 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1320 serverip from a DHCP server, it is possible that more
1321 than one DNS serverip is offered to the client.
1322 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1323 serverip will be stored in the additional environment
1324 variable "dnsip2". The first DNS serverip is always
1325 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1328 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1329 to do a dynamic update of a DNS server. To do this, they
1330 need the hostname of the DHCP requester.
1331 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1332 of the "hostname" environment variable is passed as
1333 option 12 to the DHCP server.
1335 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1337 A 32bit value in microseconds for a delay between
1338 receiving a "DHCP Offer" and sending the "DHCP Request".
1339 This fixes a problem with certain DHCP servers that don't
1340 respond 100% of the time to a "DHCP request". E.g. On an
1341 AT91RM9200 processor running at 180MHz, this delay needed
1342 to be *at least* 15,000 usec before a Windows Server 2003
1343 DHCP server would reply 100% of the time. I recommend at
1344 least 50,000 usec to be safe. The alternative is to hope
1345 that one of the retries will be successful but note that
1346 the DHCP timeout and retry process takes a longer than
1350 CONFIG_CDP_DEVICE_ID
1352 The device id used in CDP trigger frames.
1354 CONFIG_CDP_DEVICE_ID_PREFIX
1356 A two character string which is prefixed to the MAC address
1361 A printf format string which contains the ascii name of
1362 the port. Normally is set to "eth%d" which sets
1363 eth0 for the first Ethernet, eth1 for the second etc.
1365 CONFIG_CDP_CAPABILITIES
1367 A 32bit integer which indicates the device capabilities;
1368 0x00000010 for a normal host which does not forwards.
1372 An ascii string containing the version of the software.
1376 An ascii string containing the name of the platform.
1380 A 32bit integer sent on the trigger.
1382 CONFIG_CDP_POWER_CONSUMPTION
1384 A 16bit integer containing the power consumption of the
1385 device in .1 of milliwatts.
1387 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1389 A byte containing the id of the VLAN.
1391 - Status LED: CONFIG_STATUS_LED
1393 Several configurations allow to display the current
1394 status using a LED. For instance, the LED will blink
1395 fast while running U-Boot code, stop blinking as
1396 soon as a reply to a BOOTP request was received, and
1397 start blinking slow once the Linux kernel is running
1398 (supported by a status LED driver in the Linux
1399 kernel). Defining CONFIG_STATUS_LED enables this
1402 - CAN Support: CONFIG_CAN_DRIVER
1404 Defining CONFIG_CAN_DRIVER enables CAN driver support
1405 on those systems that support this (optional)
1406 feature, like the TQM8xxL modules.
1408 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1410 These enable I2C serial bus commands. Defining either of
1411 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1412 include the appropriate I2C driver for the selected CPU.
1414 This will allow you to use i2c commands at the u-boot
1415 command line (as long as you set CONFIG_CMD_I2C in
1416 CONFIG_COMMANDS) and communicate with i2c based realtime
1417 clock chips. See common/cmd_i2c.c for a description of the
1418 command line interface.
1420 CONFIG_HARD_I2C selects a hardware I2C controller.
1422 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1423 bit-banging) driver instead of CPM or similar hardware
1426 There are several other quantities that must also be
1427 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1429 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1430 to be the frequency (in Hz) at which you wish your i2c bus
1431 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1432 the CPU's i2c node address).
1434 Now, the u-boot i2c code for the mpc8xx
1435 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1436 and so its address should therefore be cleared to 0 (See,
1437 eg, MPC823e User's Manual p.16-473). So, set
1438 CONFIG_SYS_I2C_SLAVE to 0.
1440 CONFIG_SYS_I2C_INIT_MPC5XXX
1442 When a board is reset during an i2c bus transfer
1443 chips might think that the current transfer is still
1444 in progress. Reset the slave devices by sending start
1445 commands until the slave device responds.
1447 That's all that's required for CONFIG_HARD_I2C.
1449 If you use the software i2c interface (CONFIG_SOFT_I2C)
1450 then the following macros need to be defined (examples are
1451 from include/configs/lwmon.h):
1455 (Optional). Any commands necessary to enable the I2C
1456 controller or configure ports.
1458 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1462 (Only for MPC8260 CPU). The I/O port to use (the code
1463 assumes both bits are on the same port). Valid values
1464 are 0..3 for ports A..D.
1468 The code necessary to make the I2C data line active
1469 (driven). If the data line is open collector, this
1472 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1476 The code necessary to make the I2C data line tri-stated
1477 (inactive). If the data line is open collector, this
1480 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1484 Code that returns TRUE if the I2C data line is high,
1487 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1491 If <bit> is TRUE, sets the I2C data line high. If it
1492 is FALSE, it clears it (low).
1494 eg: #define I2C_SDA(bit) \
1495 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1496 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1500 If <bit> is TRUE, sets the I2C clock line high. If it
1501 is FALSE, it clears it (low).
1503 eg: #define I2C_SCL(bit) \
1504 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1505 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1509 This delay is invoked four times per clock cycle so this
1510 controls the rate of data transfer. The data rate thus
1511 is 1 / (I2C_DELAY * 4). Often defined to be something
1514 #define I2C_DELAY udelay(2)
1516 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1518 If your arch supports the generic GPIO framework (asm/gpio.h),
1519 then you may alternatively define the two GPIOs that are to be
1520 used as SCL / SDA. Any of the previous I2C_xxx macros will
1521 have GPIO-based defaults assigned to them as appropriate.
1523 You should define these to the GPIO value as given directly to
1524 the generic GPIO functions.
1526 CONFIG_SYS_I2C_INIT_BOARD
1528 When a board is reset during an i2c bus transfer
1529 chips might think that the current transfer is still
1530 in progress. On some boards it is possible to access
1531 the i2c SCLK line directly, either by using the
1532 processor pin as a GPIO or by having a second pin
1533 connected to the bus. If this option is defined a
1534 custom i2c_init_board() routine in boards/xxx/board.c
1535 is run early in the boot sequence.
1537 CONFIG_SYS_I2C_BOARD_LATE_INIT
1539 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1540 defined a custom i2c_board_late_init() routine in
1541 boards/xxx/board.c is run AFTER the operations in i2c_init()
1542 is completed. This callpoint can be used to unreset i2c bus
1543 using CPU i2c controller register accesses for CPUs whose i2c
1544 controller provide such a method. It is called at the end of
1545 i2c_init() to allow i2c_init operations to setup the i2c bus
1546 controller on the CPU (e.g. setting bus speed & slave address).
1548 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1550 This option enables configuration of bi_iic_fast[] flags
1551 in u-boot bd_info structure based on u-boot environment
1552 variable "i2cfast". (see also i2cfast)
1554 CONFIG_I2C_MULTI_BUS
1556 This option allows the use of multiple I2C buses, each of which
1557 must have a controller. At any point in time, only one bus is
1558 active. To switch to a different bus, use the 'i2c dev' command.
1559 Note that bus numbering is zero-based.
1561 CONFIG_SYS_I2C_NOPROBES
1563 This option specifies a list of I2C devices that will be skipped
1564 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1565 is set, specify a list of bus-device pairs. Otherwise, specify
1566 a 1D array of device addresses
1569 #undef CONFIG_I2C_MULTI_BUS
1570 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1572 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1574 #define CONFIG_I2C_MULTI_BUS
1575 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1577 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1579 CONFIG_SYS_SPD_BUS_NUM
1581 If defined, then this indicates the I2C bus number for DDR SPD.
1582 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1584 CONFIG_SYS_RTC_BUS_NUM
1586 If defined, then this indicates the I2C bus number for the RTC.
1587 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1589 CONFIG_SYS_DTT_BUS_NUM
1591 If defined, then this indicates the I2C bus number for the DTT.
1592 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1594 CONFIG_SYS_I2C_DTT_ADDR:
1596 If defined, specifies the I2C address of the DTT device.
1597 If not defined, then U-Boot uses predefined value for
1598 specified DTT device.
1602 Define this option if you want to use Freescale's I2C driver in
1603 drivers/i2c/fsl_i2c.c.
1607 Define this option if you have I2C devices reached over 1 .. n
1608 I2C Muxes like the pca9544a. This option addes a new I2C
1609 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1610 new I2C Bus to the existing I2C Busses. If you select the
1611 new Bus with "i2c dev", u-bbot sends first the commandos for
1612 the muxes to activate this new "bus".
1614 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1618 Adding a new I2C Bus reached over 2 pca9544a muxes
1619 The First mux with address 70 and channel 6
1620 The Second mux with address 71 and channel 4
1622 => i2c bus pca9544a:70:6:pca9544a:71:4
1624 Use the "i2c bus" command without parameter, to get a list
1625 of I2C Busses with muxes:
1628 Busses reached over muxes:
1630 reached over Mux(es):
1633 reached over Mux(es):
1638 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1639 u-boot sends First the Commando to the mux@70 to enable
1640 channel 6, and then the Commando to the mux@71 to enable
1643 After that, you can use the "normal" i2c commands as
1644 usual, to communicate with your I2C devices behind
1647 This option is actually implemented for the bitbanging
1648 algorithm in common/soft_i2c.c and for the Hardware I2C
1649 Bus on the MPC8260. But it should be not so difficult
1650 to add this option to other architectures.
1652 CONFIG_SOFT_I2C_READ_REPEATED_START
1654 defining this will force the i2c_read() function in
1655 the soft_i2c driver to perform an I2C repeated start
1656 between writing the address pointer and reading the
1657 data. If this define is omitted the default behaviour
1658 of doing a stop-start sequence will be used. Most I2C
1659 devices can use either method, but some require one or
1662 - SPI Support: CONFIG_SPI
1664 Enables SPI driver (so far only tested with
1665 SPI EEPROM, also an instance works with Crystal A/D and
1666 D/As on the SACSng board)
1670 Enables the driver for SPI controller on SuperH. Currently
1671 only SH7757 is supported.
1675 Enables extended (16-bit) SPI EEPROM addressing.
1676 (symmetrical to CONFIG_I2C_X)
1680 Enables a software (bit-bang) SPI driver rather than
1681 using hardware support. This is a general purpose
1682 driver that only requires three general I/O port pins
1683 (two outputs, one input) to function. If this is
1684 defined, the board configuration must define several
1685 SPI configuration items (port pins to use, etc). For
1686 an example, see include/configs/sacsng.h.
1690 Enables a hardware SPI driver for general-purpose reads
1691 and writes. As with CONFIG_SOFT_SPI, the board configuration
1692 must define a list of chip-select function pointers.
1693 Currently supported on some MPC8xxx processors. For an
1694 example, see include/configs/mpc8349emds.h.
1698 Enables the driver for the SPI controllers on i.MX and MXC
1699 SoCs. Currently only i.MX31 is supported.
1701 - FPGA Support: CONFIG_FPGA
1703 Enables FPGA subsystem.
1705 CONFIG_FPGA_<vendor>
1707 Enables support for specific chip vendors.
1710 CONFIG_FPGA_<family>
1712 Enables support for FPGA family.
1713 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1717 Specify the number of FPGA devices to support.
1719 CONFIG_SYS_FPGA_PROG_FEEDBACK
1721 Enable printing of hash marks during FPGA configuration.
1723 CONFIG_SYS_FPGA_CHECK_BUSY
1725 Enable checks on FPGA configuration interface busy
1726 status by the configuration function. This option
1727 will require a board or device specific function to
1732 If defined, a function that provides delays in the FPGA
1733 configuration driver.
1735 CONFIG_SYS_FPGA_CHECK_CTRLC
1736 Allow Control-C to interrupt FPGA configuration
1738 CONFIG_SYS_FPGA_CHECK_ERROR
1740 Check for configuration errors during FPGA bitfile
1741 loading. For example, abort during Virtex II
1742 configuration if the INIT_B line goes low (which
1743 indicated a CRC error).
1745 CONFIG_SYS_FPGA_WAIT_INIT
1747 Maximum time to wait for the INIT_B line to deassert
1748 after PROB_B has been deasserted during a Virtex II
1749 FPGA configuration sequence. The default time is 500
1752 CONFIG_SYS_FPGA_WAIT_BUSY
1754 Maximum time to wait for BUSY to deassert during
1755 Virtex II FPGA configuration. The default is 5 ms.
1757 CONFIG_SYS_FPGA_WAIT_CONFIG
1759 Time to wait after FPGA configuration. The default is
1762 - Configuration Management:
1765 If defined, this string will be added to the U-Boot
1766 version information (U_BOOT_VERSION)
1768 - Vendor Parameter Protection:
1770 U-Boot considers the values of the environment
1771 variables "serial#" (Board Serial Number) and
1772 "ethaddr" (Ethernet Address) to be parameters that
1773 are set once by the board vendor / manufacturer, and
1774 protects these variables from casual modification by
1775 the user. Once set, these variables are read-only,
1776 and write or delete attempts are rejected. You can
1777 change this behaviour:
1779 If CONFIG_ENV_OVERWRITE is #defined in your config
1780 file, the write protection for vendor parameters is
1781 completely disabled. Anybody can change or delete
1784 Alternatively, if you #define _both_ CONFIG_ETHADDR
1785 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1786 Ethernet address is installed in the environment,
1787 which can be changed exactly ONCE by the user. [The
1788 serial# is unaffected by this, i. e. it remains
1794 Define this variable to enable the reservation of
1795 "protected RAM", i. e. RAM which is not overwritten
1796 by U-Boot. Define CONFIG_PRAM to hold the number of
1797 kB you want to reserve for pRAM. You can overwrite
1798 this default value by defining an environment
1799 variable "pram" to the number of kB you want to
1800 reserve. Note that the board info structure will
1801 still show the full amount of RAM. If pRAM is
1802 reserved, a new environment variable "mem" will
1803 automatically be defined to hold the amount of
1804 remaining RAM in a form that can be passed as boot
1805 argument to Linux, for instance like that:
1807 setenv bootargs ... mem=\${mem}
1810 This way you can tell Linux not to use this memory,
1811 either, which results in a memory region that will
1812 not be affected by reboots.
1814 *WARNING* If your board configuration uses automatic
1815 detection of the RAM size, you must make sure that
1816 this memory test is non-destructive. So far, the
1817 following board configurations are known to be
1820 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1821 HERMES, IP860, RPXlite, LWMON, LANTEC,
1827 Define this variable to stop the system in case of a
1828 fatal error, so that you have to reset it manually.
1829 This is probably NOT a good idea for an embedded
1830 system where you want the system to reboot
1831 automatically as fast as possible, but it may be
1832 useful during development since you can try to debug
1833 the conditions that lead to the situation.
1835 CONFIG_NET_RETRY_COUNT
1837 This variable defines the number of retries for
1838 network operations like ARP, RARP, TFTP, or BOOTP
1839 before giving up the operation. If not defined, a
1840 default value of 5 is used.
1844 Timeout waiting for an ARP reply in milliseconds.
1846 - Command Interpreter:
1847 CONFIG_AUTO_COMPLETE
1849 Enable auto completion of commands using TAB.
1851 Note that this feature has NOT been implemented yet
1852 for the "hush" shell.
1855 CONFIG_SYS_HUSH_PARSER
1857 Define this variable to enable the "hush" shell (from
1858 Busybox) as command line interpreter, thus enabling
1859 powerful command line syntax like
1860 if...then...else...fi conditionals or `&&' and '||'
1861 constructs ("shell scripts").
1863 If undefined, you get the old, much simpler behaviour
1864 with a somewhat smaller memory footprint.
1867 CONFIG_SYS_PROMPT_HUSH_PS2
1869 This defines the secondary prompt string, which is
1870 printed when the command interpreter needs more input
1871 to complete a command. Usually "> ".
1875 In the current implementation, the local variables
1876 space and global environment variables space are
1877 separated. Local variables are those you define by
1878 simply typing `name=value'. To access a local
1879 variable later on, you have write `$name' or
1880 `${name}'; to execute the contents of a variable
1881 directly type `$name' at the command prompt.
1883 Global environment variables are those you use
1884 setenv/printenv to work with. To run a command stored
1885 in such a variable, you need to use the run command,
1886 and you must not use the '$' sign to access them.
1888 To store commands and special characters in a
1889 variable, please use double quotation marks
1890 surrounding the whole text of the variable, instead
1891 of the backslashes before semicolons and special
1894 - Commandline Editing and History:
1895 CONFIG_CMDLINE_EDITING
1897 Enable editing and History functions for interactive
1898 commandline input operations
1900 - Default Environment:
1901 CONFIG_EXTRA_ENV_SETTINGS
1903 Define this to contain any number of null terminated
1904 strings (variable = value pairs) that will be part of
1905 the default environment compiled into the boot image.
1907 For example, place something like this in your
1908 board's config file:
1910 #define CONFIG_EXTRA_ENV_SETTINGS \
1914 Warning: This method is based on knowledge about the
1915 internal format how the environment is stored by the
1916 U-Boot code. This is NOT an official, exported
1917 interface! Although it is unlikely that this format
1918 will change soon, there is no guarantee either.
1919 You better know what you are doing here.
1921 Note: overly (ab)use of the default environment is
1922 discouraged. Make sure to check other ways to preset
1923 the environment like the "source" command or the
1926 - DataFlash Support:
1927 CONFIG_HAS_DATAFLASH
1929 Defining this option enables DataFlash features and
1930 allows to read/write in Dataflash via the standard
1933 - SystemACE Support:
1936 Adding this option adds support for Xilinx SystemACE
1937 chips attached via some sort of local bus. The address
1938 of the chip must also be defined in the
1939 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1941 #define CONFIG_SYSTEMACE
1942 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1944 When SystemACE support is added, the "ace" device type
1945 becomes available to the fat commands, i.e. fatls.
1947 - TFTP Fixed UDP Port:
1950 If this is defined, the environment variable tftpsrcp
1951 is used to supply the TFTP UDP source port value.
1952 If tftpsrcp isn't defined, the normal pseudo-random port
1953 number generator is used.
1955 Also, the environment variable tftpdstp is used to supply
1956 the TFTP UDP destination port value. If tftpdstp isn't
1957 defined, the normal port 69 is used.
1959 The purpose for tftpsrcp is to allow a TFTP server to
1960 blindly start the TFTP transfer using the pre-configured
1961 target IP address and UDP port. This has the effect of
1962 "punching through" the (Windows XP) firewall, allowing
1963 the remainder of the TFTP transfer to proceed normally.
1964 A better solution is to properly configure the firewall,
1965 but sometimes that is not allowed.
1967 - Show boot progress:
1968 CONFIG_SHOW_BOOT_PROGRESS
1970 Defining this option allows to add some board-
1971 specific code (calling a user-provided function
1972 "show_boot_progress(int)") that enables you to show
1973 the system's boot progress on some display (for
1974 example, some LED's) on your board. At the moment,
1975 the following checkpoints are implemented:
1977 Legacy uImage format:
1980 1 common/cmd_bootm.c before attempting to boot an image
1981 -1 common/cmd_bootm.c Image header has bad magic number
1982 2 common/cmd_bootm.c Image header has correct magic number
1983 -2 common/cmd_bootm.c Image header has bad checksum
1984 3 common/cmd_bootm.c Image header has correct checksum
1985 -3 common/cmd_bootm.c Image data has bad checksum
1986 4 common/cmd_bootm.c Image data has correct checksum
1987 -4 common/cmd_bootm.c Image is for unsupported architecture
1988 5 common/cmd_bootm.c Architecture check OK
1989 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1990 6 common/cmd_bootm.c Image Type check OK
1991 -6 common/cmd_bootm.c gunzip uncompression error
1992 -7 common/cmd_bootm.c Unimplemented compression type
1993 7 common/cmd_bootm.c Uncompression OK
1994 8 common/cmd_bootm.c No uncompress/copy overwrite error
1995 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1997 9 common/image.c Start initial ramdisk verification
1998 -10 common/image.c Ramdisk header has bad magic number
1999 -11 common/image.c Ramdisk header has bad checksum
2000 10 common/image.c Ramdisk header is OK
2001 -12 common/image.c Ramdisk data has bad checksum
2002 11 common/image.c Ramdisk data has correct checksum
2003 12 common/image.c Ramdisk verification complete, start loading
2004 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2005 13 common/image.c Start multifile image verification
2006 14 common/image.c No initial ramdisk, no multifile, continue.
2008 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2010 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2011 -31 post/post.c POST test failed, detected by post_output_backlog()
2012 -32 post/post.c POST test failed, detected by post_run_single()
2014 34 common/cmd_doc.c before loading a Image from a DOC device
2015 -35 common/cmd_doc.c Bad usage of "doc" command
2016 35 common/cmd_doc.c correct usage of "doc" command
2017 -36 common/cmd_doc.c No boot device
2018 36 common/cmd_doc.c correct boot device
2019 -37 common/cmd_doc.c Unknown Chip ID on boot device
2020 37 common/cmd_doc.c correct chip ID found, device available
2021 -38 common/cmd_doc.c Read Error on boot device
2022 38 common/cmd_doc.c reading Image header from DOC device OK
2023 -39 common/cmd_doc.c Image header has bad magic number
2024 39 common/cmd_doc.c Image header has correct magic number
2025 -40 common/cmd_doc.c Error reading Image from DOC device
2026 40 common/cmd_doc.c Image header has correct magic number
2027 41 common/cmd_ide.c before loading a Image from a IDE device
2028 -42 common/cmd_ide.c Bad usage of "ide" command
2029 42 common/cmd_ide.c correct usage of "ide" command
2030 -43 common/cmd_ide.c No boot device
2031 43 common/cmd_ide.c boot device found
2032 -44 common/cmd_ide.c Device not available
2033 44 common/cmd_ide.c Device available
2034 -45 common/cmd_ide.c wrong partition selected
2035 45 common/cmd_ide.c partition selected
2036 -46 common/cmd_ide.c Unknown partition table
2037 46 common/cmd_ide.c valid partition table found
2038 -47 common/cmd_ide.c Invalid partition type
2039 47 common/cmd_ide.c correct partition type
2040 -48 common/cmd_ide.c Error reading Image Header on boot device
2041 48 common/cmd_ide.c reading Image Header from IDE device OK
2042 -49 common/cmd_ide.c Image header has bad magic number
2043 49 common/cmd_ide.c Image header has correct magic number
2044 -50 common/cmd_ide.c Image header has bad checksum
2045 50 common/cmd_ide.c Image header has correct checksum
2046 -51 common/cmd_ide.c Error reading Image from IDE device
2047 51 common/cmd_ide.c reading Image from IDE device OK
2048 52 common/cmd_nand.c before loading a Image from a NAND device
2049 -53 common/cmd_nand.c Bad usage of "nand" command
2050 53 common/cmd_nand.c correct usage of "nand" command
2051 -54 common/cmd_nand.c No boot device
2052 54 common/cmd_nand.c boot device found
2053 -55 common/cmd_nand.c Unknown Chip ID on boot device
2054 55 common/cmd_nand.c correct chip ID found, device available
2055 -56 common/cmd_nand.c Error reading Image Header on boot device
2056 56 common/cmd_nand.c reading Image Header from NAND device OK
2057 -57 common/cmd_nand.c Image header has bad magic number
2058 57 common/cmd_nand.c Image header has correct magic number
2059 -58 common/cmd_nand.c Error reading Image from NAND device
2060 58 common/cmd_nand.c reading Image from NAND device OK
2062 -60 common/env_common.c Environment has a bad CRC, using default
2064 64 net/eth.c starting with Ethernet configuration.
2065 -64 net/eth.c no Ethernet found.
2066 65 net/eth.c Ethernet found.
2068 -80 common/cmd_net.c usage wrong
2069 80 common/cmd_net.c before calling NetLoop()
2070 -81 common/cmd_net.c some error in NetLoop() occurred
2071 81 common/cmd_net.c NetLoop() back without error
2072 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2073 82 common/cmd_net.c trying automatic boot
2074 83 common/cmd_net.c running "source" command
2075 -83 common/cmd_net.c some error in automatic boot or "source" command
2076 84 common/cmd_net.c end without errors
2081 100 common/cmd_bootm.c Kernel FIT Image has correct format
2082 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2083 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2084 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2085 102 common/cmd_bootm.c Kernel unit name specified
2086 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2087 103 common/cmd_bootm.c Found configuration node
2088 104 common/cmd_bootm.c Got kernel subimage node offset
2089 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2090 105 common/cmd_bootm.c Kernel subimage hash verification OK
2091 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2092 106 common/cmd_bootm.c Architecture check OK
2093 -106 common/cmd_bootm.c Kernel subimage has wrong type
2094 107 common/cmd_bootm.c Kernel subimage type OK
2095 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2096 108 common/cmd_bootm.c Got kernel subimage data/size
2097 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2098 -109 common/cmd_bootm.c Can't get kernel subimage type
2099 -110 common/cmd_bootm.c Can't get kernel subimage comp
2100 -111 common/cmd_bootm.c Can't get kernel subimage os
2101 -112 common/cmd_bootm.c Can't get kernel subimage load address
2102 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2104 120 common/image.c Start initial ramdisk verification
2105 -120 common/image.c Ramdisk FIT image has incorrect format
2106 121 common/image.c Ramdisk FIT image has correct format
2107 122 common/image.c No ramdisk subimage unit name, using configuration
2108 -122 common/image.c Can't get configuration for ramdisk subimage
2109 123 common/image.c Ramdisk unit name specified
2110 -124 common/image.c Can't get ramdisk subimage node offset
2111 125 common/image.c Got ramdisk subimage node offset
2112 -125 common/image.c Ramdisk subimage hash verification failed
2113 126 common/image.c Ramdisk subimage hash verification OK
2114 -126 common/image.c Ramdisk subimage for unsupported architecture
2115 127 common/image.c Architecture check OK
2116 -127 common/image.c Can't get ramdisk subimage data/size
2117 128 common/image.c Got ramdisk subimage data/size
2118 129 common/image.c Can't get ramdisk load address
2119 -129 common/image.c Got ramdisk load address
2121 -130 common/cmd_doc.c Incorrect FIT image format
2122 131 common/cmd_doc.c FIT image format OK
2124 -140 common/cmd_ide.c Incorrect FIT image format
2125 141 common/cmd_ide.c FIT image format OK
2127 -150 common/cmd_nand.c Incorrect FIT image format
2128 151 common/cmd_nand.c FIT image format OK
2130 - Automatic software updates via TFTP server
2132 CONFIG_UPDATE_TFTP_CNT_MAX
2133 CONFIG_UPDATE_TFTP_MSEC_MAX
2135 These options enable and control the auto-update feature;
2136 for a more detailed description refer to doc/README.update.
2138 - MTD Support (mtdparts command, UBI support)
2141 Adds the MTD device infrastructure from the Linux kernel.
2142 Needed for mtdparts command support.
2144 CONFIG_MTD_PARTITIONS
2146 Adds the MTD partitioning infrastructure from the Linux
2147 kernel. Needed for UBI support.
2153 [so far only for SMDK2400 and TRAB boards]
2155 - Modem support enable:
2156 CONFIG_MODEM_SUPPORT
2158 - RTS/CTS Flow control enable:
2161 - Modem debug support:
2162 CONFIG_MODEM_SUPPORT_DEBUG
2164 Enables debugging stuff (char screen[1024], dbg())
2165 for modem support. Useful only with BDI2000.
2167 - Interrupt support (PPC):
2169 There are common interrupt_init() and timer_interrupt()
2170 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2171 for CPU specific initialization. interrupt_init_cpu()
2172 should set decrementer_count to appropriate value. If
2173 CPU resets decrementer automatically after interrupt
2174 (ppc4xx) it should set decrementer_count to zero.
2175 timer_interrupt() calls timer_interrupt_cpu() for CPU
2176 specific handling. If board has watchdog / status_led
2177 / other_activity_monitor it works automatically from
2178 general timer_interrupt().
2182 In the target system modem support is enabled when a
2183 specific key (key combination) is pressed during
2184 power-on. Otherwise U-Boot will boot normally
2185 (autoboot). The key_pressed() function is called from
2186 board_init(). Currently key_pressed() is a dummy
2187 function, returning 1 and thus enabling modem
2190 If there are no modem init strings in the
2191 environment, U-Boot proceed to autoboot; the
2192 previous output (banner, info printfs) will be
2195 See also: doc/README.Modem
2198 Configuration Settings:
2199 -----------------------
2201 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2202 undefine this when you're short of memory.
2204 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2205 width of the commands listed in the 'help' command output.
2207 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2208 prompt for user input.
2210 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2212 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2214 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2216 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2217 the application (usually a Linux kernel) when it is
2220 - CONFIG_SYS_BAUDRATE_TABLE:
2221 List of legal baudrate settings for this board.
2223 - CONFIG_SYS_CONSOLE_INFO_QUIET
2224 Suppress display of console information at boot.
2226 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2227 If the board specific function
2228 extern int overwrite_console (void);
2229 returns 1, the stdin, stderr and stdout are switched to the
2230 serial port, else the settings in the environment are used.
2232 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2233 Enable the call to overwrite_console().
2235 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2236 Enable overwrite of previous console environment settings.
2238 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2239 Begin and End addresses of the area used by the
2242 - CONFIG_SYS_ALT_MEMTEST:
2243 Enable an alternate, more extensive memory test.
2245 - CONFIG_SYS_MEMTEST_SCRATCH:
2246 Scratch address used by the alternate memory test
2247 You only need to set this if address zero isn't writeable
2249 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2250 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2251 this specified memory area will get subtracted from the top
2252 (end) of RAM and won't get "touched" at all by U-Boot. By
2253 fixing up gd->ram_size the Linux kernel should gets passed
2254 the now "corrected" memory size and won't touch it either.
2255 This should work for arch/ppc and arch/powerpc. Only Linux
2256 board ports in arch/powerpc with bootwrapper support that
2257 recalculate the memory size from the SDRAM controller setup
2258 will have to get fixed in Linux additionally.
2260 This option can be used as a workaround for the 440EPx/GRx
2261 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2264 WARNING: Please make sure that this value is a multiple of
2265 the Linux page size (normally 4k). If this is not the case,
2266 then the end address of the Linux memory will be located at a
2267 non page size aligned address and this could cause major
2270 - CONFIG_SYS_TFTP_LOADADDR:
2271 Default load address for network file downloads
2273 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2274 Enable temporary baudrate change while serial download
2276 - CONFIG_SYS_SDRAM_BASE:
2277 Physical start address of SDRAM. _Must_ be 0 here.
2279 - CONFIG_SYS_MBIO_BASE:
2280 Physical start address of Motherboard I/O (if using a
2283 - CONFIG_SYS_FLASH_BASE:
2284 Physical start address of Flash memory.
2286 - CONFIG_SYS_MONITOR_BASE:
2287 Physical start address of boot monitor code (set by
2288 make config files to be same as the text base address
2289 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2290 CONFIG_SYS_FLASH_BASE when booting from flash.
2292 - CONFIG_SYS_MONITOR_LEN:
2293 Size of memory reserved for monitor code, used to
2294 determine _at_compile_time_ (!) if the environment is
2295 embedded within the U-Boot image, or in a separate
2298 - CONFIG_SYS_MALLOC_LEN:
2299 Size of DRAM reserved for malloc() use.
2301 - CONFIG_SYS_BOOTM_LEN:
2302 Normally compressed uImages are limited to an
2303 uncompressed size of 8 MBytes. If this is not enough,
2304 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2305 to adjust this setting to your needs.
2307 - CONFIG_SYS_BOOTMAPSZ:
2308 Maximum size of memory mapped by the startup code of
2309 the Linux kernel; all data that must be processed by
2310 the Linux kernel (bd_info, boot arguments, FDT blob if
2311 used) must be put below this limit, unless "bootm_low"
2312 enviroment variable is defined and non-zero. In such case
2313 all data for the Linux kernel must be between "bootm_low"
2314 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2316 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2317 Enable initrd_high functionality. If defined then the
2318 initrd_high feature is enabled and the bootm ramdisk subcommand
2321 - CONFIG_SYS_BOOT_GET_CMDLINE:
2322 Enables allocating and saving kernel cmdline in space between
2323 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2325 - CONFIG_SYS_BOOT_GET_KBD:
2326 Enables allocating and saving a kernel copy of the bd_info in
2327 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2329 - CONFIG_SYS_MAX_FLASH_BANKS:
2330 Max number of Flash memory banks
2332 - CONFIG_SYS_MAX_FLASH_SECT:
2333 Max number of sectors on a Flash chip
2335 - CONFIG_SYS_FLASH_ERASE_TOUT:
2336 Timeout for Flash erase operations (in ms)
2338 - CONFIG_SYS_FLASH_WRITE_TOUT:
2339 Timeout for Flash write operations (in ms)
2341 - CONFIG_SYS_FLASH_LOCK_TOUT
2342 Timeout for Flash set sector lock bit operation (in ms)
2344 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2345 Timeout for Flash clear lock bits operation (in ms)
2347 - CONFIG_SYS_FLASH_PROTECTION
2348 If defined, hardware flash sectors protection is used
2349 instead of U-Boot software protection.
2351 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2353 Enable TFTP transfers directly to flash memory;
2354 without this option such a download has to be
2355 performed in two steps: (1) download to RAM, and (2)
2356 copy from RAM to flash.
2358 The two-step approach is usually more reliable, since
2359 you can check if the download worked before you erase
2360 the flash, but in some situations (when system RAM is
2361 too limited to allow for a temporary copy of the
2362 downloaded image) this option may be very useful.
2364 - CONFIG_SYS_FLASH_CFI:
2365 Define if the flash driver uses extra elements in the
2366 common flash structure for storing flash geometry.
2368 - CONFIG_FLASH_CFI_DRIVER
2369 This option also enables the building of the cfi_flash driver
2370 in the drivers directory
2372 - CONFIG_FLASH_CFI_MTD
2373 This option enables the building of the cfi_mtd driver
2374 in the drivers directory. The driver exports CFI flash
2377 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2378 Use buffered writes to flash.
2380 - CONFIG_FLASH_SPANSION_S29WS_N
2381 s29ws-n MirrorBit flash has non-standard addresses for buffered
2384 - CONFIG_SYS_FLASH_QUIET_TEST
2385 If this option is defined, the common CFI flash doesn't
2386 print it's warning upon not recognized FLASH banks. This
2387 is useful, if some of the configured banks are only
2388 optionally available.
2390 - CONFIG_FLASH_SHOW_PROGRESS
2391 If defined (must be an integer), print out countdown
2392 digits and dots. Recommended value: 45 (9..1) for 80
2393 column displays, 15 (3..1) for 40 column displays.
2395 - CONFIG_SYS_RX_ETH_BUFFER:
2396 Defines the number of Ethernet receive buffers. On some
2397 Ethernet controllers it is recommended to set this value
2398 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2399 buffers can be full shortly after enabling the interface
2400 on high Ethernet traffic.
2401 Defaults to 4 if not defined.
2403 - CONFIG_ENV_MAX_ENTRIES
2405 Maximum number of entries in the hash table that is used
2406 internally to store the environment settings. The default
2407 setting is supposed to be generous and should work in most
2408 cases. This setting can be used to tune behaviour; see
2409 lib/hashtable.c for details.
2411 The following definitions that deal with the placement and management
2412 of environment data (variable area); in general, we support the
2413 following configurations:
2415 - CONFIG_ENV_IS_IN_FLASH:
2417 Define this if the environment is in flash memory.
2419 a) The environment occupies one whole flash sector, which is
2420 "embedded" in the text segment with the U-Boot code. This
2421 happens usually with "bottom boot sector" or "top boot
2422 sector" type flash chips, which have several smaller
2423 sectors at the start or the end. For instance, such a
2424 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2425 such a case you would place the environment in one of the
2426 4 kB sectors - with U-Boot code before and after it. With
2427 "top boot sector" type flash chips, you would put the
2428 environment in one of the last sectors, leaving a gap
2429 between U-Boot and the environment.
2431 - CONFIG_ENV_OFFSET:
2433 Offset of environment data (variable area) to the
2434 beginning of flash memory; for instance, with bottom boot
2435 type flash chips the second sector can be used: the offset
2436 for this sector is given here.
2438 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2442 This is just another way to specify the start address of
2443 the flash sector containing the environment (instead of
2446 - CONFIG_ENV_SECT_SIZE:
2448 Size of the sector containing the environment.
2451 b) Sometimes flash chips have few, equal sized, BIG sectors.
2452 In such a case you don't want to spend a whole sector for
2457 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2458 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2459 of this flash sector for the environment. This saves
2460 memory for the RAM copy of the environment.
2462 It may also save flash memory if you decide to use this
2463 when your environment is "embedded" within U-Boot code,
2464 since then the remainder of the flash sector could be used
2465 for U-Boot code. It should be pointed out that this is
2466 STRONGLY DISCOURAGED from a robustness point of view:
2467 updating the environment in flash makes it always
2468 necessary to erase the WHOLE sector. If something goes
2469 wrong before the contents has been restored from a copy in
2470 RAM, your target system will be dead.
2472 - CONFIG_ENV_ADDR_REDUND
2473 CONFIG_ENV_SIZE_REDUND
2475 These settings describe a second storage area used to hold
2476 a redundant copy of the environment data, so that there is
2477 a valid backup copy in case there is a power failure during
2478 a "saveenv" operation.
2480 BE CAREFUL! Any changes to the flash layout, and some changes to the
2481 source code will make it necessary to adapt <board>/u-boot.lds*
2485 - CONFIG_ENV_IS_IN_NVRAM:
2487 Define this if you have some non-volatile memory device
2488 (NVRAM, battery buffered SRAM) which you want to use for the
2494 These two #defines are used to determine the memory area you
2495 want to use for environment. It is assumed that this memory
2496 can just be read and written to, without any special
2499 BE CAREFUL! The first access to the environment happens quite early
2500 in U-Boot initalization (when we try to get the setting of for the
2501 console baudrate). You *MUST* have mapped your NVRAM area then, or
2504 Please note that even with NVRAM we still use a copy of the
2505 environment in RAM: we could work on NVRAM directly, but we want to
2506 keep settings there always unmodified except somebody uses "saveenv"
2507 to save the current settings.
2510 - CONFIG_ENV_IS_IN_EEPROM:
2512 Use this if you have an EEPROM or similar serial access
2513 device and a driver for it.
2515 - CONFIG_ENV_OFFSET:
2518 These two #defines specify the offset and size of the
2519 environment area within the total memory of your EEPROM.
2521 - CONFIG_SYS_I2C_EEPROM_ADDR:
2522 If defined, specified the chip address of the EEPROM device.
2523 The default address is zero.
2525 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2526 If defined, the number of bits used to address bytes in a
2527 single page in the EEPROM device. A 64 byte page, for example
2528 would require six bits.
2530 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2531 If defined, the number of milliseconds to delay between
2532 page writes. The default is zero milliseconds.
2534 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2535 The length in bytes of the EEPROM memory array address. Note
2536 that this is NOT the chip address length!
2538 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2539 EEPROM chips that implement "address overflow" are ones
2540 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2541 address and the extra bits end up in the "chip address" bit
2542 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2545 Note that we consider the length of the address field to
2546 still be one byte because the extra address bits are hidden
2547 in the chip address.
2549 - CONFIG_SYS_EEPROM_SIZE:
2550 The size in bytes of the EEPROM device.
2552 - CONFIG_ENV_EEPROM_IS_ON_I2C
2553 define this, if you have I2C and SPI activated, and your
2554 EEPROM, which holds the environment, is on the I2C bus.
2556 - CONFIG_I2C_ENV_EEPROM_BUS
2557 if you have an Environment on an EEPROM reached over
2558 I2C muxes, you can define here, how to reach this
2559 EEPROM. For example:
2561 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2563 EEPROM which holds the environment, is reached over
2564 a pca9547 i2c mux with address 0x70, channel 3.
2566 - CONFIG_ENV_IS_IN_DATAFLASH:
2568 Define this if you have a DataFlash memory device which you
2569 want to use for the environment.
2571 - CONFIG_ENV_OFFSET:
2575 These three #defines specify the offset and size of the
2576 environment area within the total memory of your DataFlash placed
2577 at the specified address.
2579 - CONFIG_ENV_IS_IN_NAND:
2581 Define this if you have a NAND device which you want to use
2582 for the environment.
2584 - CONFIG_ENV_OFFSET:
2587 These two #defines specify the offset and size of the environment
2588 area within the first NAND device. CONFIG_ENV_OFFSET must be
2589 aligned to an erase block boundary.
2591 - CONFIG_ENV_OFFSET_REDUND (optional):
2593 This setting describes a second storage area of CONFIG_ENV_SIZE
2594 size used to hold a redundant copy of the environment data, so
2595 that there is a valid backup copy in case there is a power failure
2596 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2597 aligned to an erase block boundary.
2599 - CONFIG_ENV_RANGE (optional):
2601 Specifies the length of the region in which the environment
2602 can be written. This should be a multiple of the NAND device's
2603 block size. Specifying a range with more erase blocks than
2604 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2605 the range to be avoided.
2607 - CONFIG_ENV_OFFSET_OOB (optional):
2609 Enables support for dynamically retrieving the offset of the
2610 environment from block zero's out-of-band data. The
2611 "nand env.oob" command can be used to record this offset.
2612 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2613 using CONFIG_ENV_OFFSET_OOB.
2615 - CONFIG_NAND_ENV_DST
2617 Defines address in RAM to which the nand_spl code should copy the
2618 environment. If redundant environment is used, it will be copied to
2619 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2621 - CONFIG_SYS_SPI_INIT_OFFSET
2623 Defines offset to the initial SPI buffer area in DPRAM. The
2624 area is used at an early stage (ROM part) if the environment
2625 is configured to reside in the SPI EEPROM: We need a 520 byte
2626 scratch DPRAM area. It is used between the two initialization
2627 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2628 to be a good choice since it makes it far enough from the
2629 start of the data area as well as from the stack pointer.
2631 Please note that the environment is read-only until the monitor
2632 has been relocated to RAM and a RAM copy of the environment has been
2633 created; also, when using EEPROM you will have to use getenv_f()
2634 until then to read environment variables.
2636 The environment is protected by a CRC32 checksum. Before the monitor
2637 is relocated into RAM, as a result of a bad CRC you will be working
2638 with the compiled-in default environment - *silently*!!! [This is
2639 necessary, because the first environment variable we need is the
2640 "baudrate" setting for the console - if we have a bad CRC, we don't
2641 have any device yet where we could complain.]
2643 Note: once the monitor has been relocated, then it will complain if
2644 the default environment is used; a new CRC is computed as soon as you
2645 use the "saveenv" command to store a valid environment.
2647 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2648 Echo the inverted Ethernet link state to the fault LED.
2650 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2651 also needs to be defined.
2653 - CONFIG_SYS_FAULT_MII_ADDR:
2654 MII address of the PHY to check for the Ethernet link state.
2656 - CONFIG_NS16550_MIN_FUNCTIONS:
2657 Define this if you desire to only have use of the NS16550_init
2658 and NS16550_putc functions for the serial driver located at
2659 drivers/serial/ns16550.c. This option is useful for saving
2660 space for already greatly restricted images, including but not
2661 limited to NAND_SPL configurations.
2663 Low Level (hardware related) configuration options:
2664 ---------------------------------------------------
2666 - CONFIG_SYS_CACHELINE_SIZE:
2667 Cache Line Size of the CPU.
2669 - CONFIG_SYS_DEFAULT_IMMR:
2670 Default address of the IMMR after system reset.
2672 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2673 and RPXsuper) to be able to adjust the position of
2674 the IMMR register after a reset.
2676 - Floppy Disk Support:
2677 CONFIG_SYS_FDC_DRIVE_NUMBER
2679 the default drive number (default value 0)
2681 CONFIG_SYS_ISA_IO_STRIDE
2683 defines the spacing between FDC chipset registers
2686 CONFIG_SYS_ISA_IO_OFFSET
2688 defines the offset of register from address. It
2689 depends on which part of the data bus is connected to
2690 the FDC chipset. (default value 0)
2692 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2693 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2696 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2697 fdc_hw_init() is called at the beginning of the FDC
2698 setup. fdc_hw_init() must be provided by the board
2699 source code. It is used to make hardware dependant
2702 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2703 DO NOT CHANGE unless you know exactly what you're
2704 doing! (11-4) [MPC8xx/82xx systems only]
2706 - CONFIG_SYS_INIT_RAM_ADDR:
2708 Start address of memory area that can be used for
2709 initial data and stack; please note that this must be
2710 writable memory that is working WITHOUT special
2711 initialization, i. e. you CANNOT use normal RAM which
2712 will become available only after programming the
2713 memory controller and running certain initialization
2716 U-Boot uses the following memory types:
2717 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2718 - MPC824X: data cache
2719 - PPC4xx: data cache
2721 - CONFIG_SYS_GBL_DATA_OFFSET:
2723 Offset of the initial data structure in the memory
2724 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2725 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2726 data is located at the end of the available space
2727 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
2728 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2729 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2730 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2733 On the MPC824X (or other systems that use the data
2734 cache for initial memory) the address chosen for
2735 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2736 point to an otherwise UNUSED address space between
2737 the top of RAM and the start of the PCI space.
2739 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2741 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2743 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2745 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2747 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2749 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2751 - CONFIG_SYS_OR_TIMING_SDRAM:
2754 - CONFIG_SYS_MAMR_PTA:
2755 periodic timer for refresh
2757 - CONFIG_SYS_DER: Debug Event Register (37-47)
2759 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2760 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2761 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2762 CONFIG_SYS_BR1_PRELIM:
2763 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2765 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2766 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2767 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2768 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2770 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2771 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2772 Machine Mode Register and Memory Periodic Timer
2773 Prescaler definitions (SDRAM timing)
2775 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2776 enable I2C microcode relocation patch (MPC8xx);
2777 define relocation offset in DPRAM [DSP2]
2779 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2780 enable SMC microcode relocation patch (MPC8xx);
2781 define relocation offset in DPRAM [SMC1]
2783 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2784 enable SPI microcode relocation patch (MPC8xx);
2785 define relocation offset in DPRAM [SCC4]
2787 - CONFIG_SYS_USE_OSCCLK:
2788 Use OSCM clock mode on MBX8xx board. Be careful,
2789 wrong setting might damage your board. Read
2790 doc/README.MBX before setting this variable!
2792 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2793 Offset of the bootmode word in DPRAM used by post
2794 (Power On Self Tests). This definition overrides
2795 #define'd default value in commproc.h resp.
2798 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2799 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2800 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2801 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2802 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2803 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2804 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2805 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2806 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
2808 - CONFIG_PCI_DISABLE_PCIE:
2809 Disable PCI-Express on systems where it is supported but not
2813 Chip has SRIO or not
2816 Board has SRIO 1 port available
2819 Board has SRIO 2 port available
2821 - CONFIG_SYS_SRIOn_MEM_VIRT:
2822 Virtual Address of SRIO port 'n' memory region
2824 - CONFIG_SYS_SRIOn_MEM_PHYS:
2825 Physical Address of SRIO port 'n' memory region
2827 - CONFIG_SYS_SRIOn_MEM_SIZE:
2828 Size of SRIO port 'n' memory region
2831 Get DDR timing information from an I2C EEPROM. Common
2832 with pluggable memory modules such as SODIMMs
2835 I2C address of the SPD EEPROM
2837 - CONFIG_SYS_SPD_BUS_NUM
2838 If SPD EEPROM is on an I2C bus other than the first
2839 one, specify here. Note that the value must resolve
2840 to something your driver can deal with.
2842 - CONFIG_SYS_83XX_DDR_USES_CS0
2843 Only for 83xx systems. If specified, then DDR should
2844 be configured using CS0 and CS1 instead of CS2 and CS3.
2846 - CONFIG_ETHER_ON_FEC[12]
2847 Define to enable FEC[12] on a 8xx series processor.
2849 - CONFIG_FEC[12]_PHY
2850 Define to the hardcoded PHY address which corresponds
2851 to the given FEC; i. e.
2852 #define CONFIG_FEC1_PHY 4
2853 means that the PHY with address 4 is connected to FEC1
2855 When set to -1, means to probe for first available.
2857 - CONFIG_FEC[12]_PHY_NORXERR
2858 The PHY does not have a RXERR line (RMII only).
2859 (so program the FEC to ignore it).
2862 Enable RMII mode for all FECs.
2863 Note that this is a global option, we can't
2864 have one FEC in standard MII mode and another in RMII mode.
2866 - CONFIG_CRC32_VERIFY
2867 Add a verify option to the crc32 command.
2870 => crc32 -v <address> <count> <crc32>
2872 Where address/count indicate a memory area
2873 and crc32 is the correct crc32 which the
2877 Add the "loopw" memory command. This only takes effect if
2878 the memory commands are activated globally (CONFIG_CMD_MEM).
2881 Add the "mdc" and "mwc" memory commands. These are cyclic
2886 This command will print 4 bytes (10,11,12,13) each 500 ms.
2888 => mwc.l 100 12345678 10
2889 This command will write 12345678 to address 100 all 10 ms.
2891 This only takes effect if the memory commands are activated
2892 globally (CONFIG_CMD_MEM).
2894 - CONFIG_SKIP_LOWLEVEL_INIT
2895 [ARM only] If this variable is defined, then certain
2896 low level initializations (like setting up the memory
2897 controller) are omitted and/or U-Boot does not
2898 relocate itself into RAM.
2900 Normally this variable MUST NOT be defined. The only
2901 exception is when U-Boot is loaded (to RAM) by some
2902 other boot loader or by a debugger which performs
2903 these initializations itself.
2906 Modifies the behaviour of start.S when compiling a loader
2907 that is executed before the actual U-Boot. E.g. when
2908 compiling a NAND SPL.
2910 Building the Software:
2911 ======================
2913 Building U-Boot has been tested in several native build environments
2914 and in many different cross environments. Of course we cannot support
2915 all possibly existing versions of cross development tools in all
2916 (potentially obsolete) versions. In case of tool chain problems we
2917 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2918 which is extensively used to build and test U-Boot.
2920 If you are not using a native environment, it is assumed that you
2921 have GNU cross compiling tools available in your path. In this case,
2922 you must set the environment variable CROSS_COMPILE in your shell.
2923 Note that no changes to the Makefile or any other source files are
2924 necessary. For example using the ELDK on a 4xx CPU, please enter:
2926 $ CROSS_COMPILE=ppc_4xx-
2927 $ export CROSS_COMPILE
2929 Note: If you wish to generate Windows versions of the utilities in
2930 the tools directory you can use the MinGW toolchain
2931 (http://www.mingw.org). Set your HOST tools to the MinGW
2932 toolchain and execute 'make tools'. For example:
2934 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
2936 Binaries such as tools/mkimage.exe will be created which can
2937 be executed on computers running Windows.
2939 U-Boot is intended to be simple to build. After installing the
2940 sources you must configure U-Boot for one specific board type. This
2945 where "NAME_config" is the name of one of the existing configu-
2946 rations; see the main Makefile for supported names.
2948 Note: for some board special configuration names may exist; check if
2949 additional information is available from the board vendor; for
2950 instance, the TQM823L systems are available without (standard)
2951 or with LCD support. You can select such additional "features"
2952 when choosing the configuration, i. e.
2955 - will configure for a plain TQM823L, i. e. no LCD support
2957 make TQM823L_LCD_config
2958 - will configure for a TQM823L with U-Boot console on LCD
2963 Finally, type "make all", and you should get some working U-Boot
2964 images ready for download to / installation on your system:
2966 - "u-boot.bin" is a raw binary image
2967 - "u-boot" is an image in ELF binary format
2968 - "u-boot.srec" is in Motorola S-Record format
2970 By default the build is performed locally and the objects are saved
2971 in the source directory. One of the two methods can be used to change
2972 this behavior and build U-Boot to some external directory:
2974 1. Add O= to the make command line invocations:
2976 make O=/tmp/build distclean
2977 make O=/tmp/build NAME_config
2978 make O=/tmp/build all
2980 2. Set environment variable BUILD_DIR to point to the desired location:
2982 export BUILD_DIR=/tmp/build
2987 Note that the command line "O=" setting overrides the BUILD_DIR environment
2991 Please be aware that the Makefiles assume you are using GNU make, so
2992 for instance on NetBSD you might need to use "gmake" instead of
2996 If the system board that you have is not listed, then you will need
2997 to port U-Boot to your hardware platform. To do this, follow these
3000 1. Add a new configuration option for your board to the toplevel
3001 "Makefile" and to the "MAKEALL" script, using the existing
3002 entries as examples. Note that here and at many other places
3003 boards and other names are listed in alphabetical sort order. Please
3005 2. Create a new directory to hold your board specific code. Add any
3006 files you need. In your board directory, you will need at least
3007 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3008 3. Create a new configuration file "include/configs/<board>.h" for
3010 3. If you're porting U-Boot to a new CPU, then also create a new
3011 directory to hold your CPU specific code. Add any files you need.
3012 4. Run "make <board>_config" with your new name.
3013 5. Type "make", and you should get a working "u-boot.srec" file
3014 to be installed on your target system.
3015 6. Debug and solve any problems that might arise.
3016 [Of course, this last step is much harder than it sounds.]
3019 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3020 ==============================================================
3022 If you have modified U-Boot sources (for instance added a new board
3023 or support for new devices, a new CPU, etc.) you are expected to
3024 provide feedback to the other developers. The feedback normally takes
3025 the form of a "patch", i. e. a context diff against a certain (latest
3026 official or latest in the git repository) version of U-Boot sources.
3028 But before you submit such a patch, please verify that your modifi-
3029 cation did not break existing code. At least make sure that *ALL* of
3030 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3031 just run the "MAKEALL" script, which will configure and build U-Boot
3032 for ALL supported system. Be warned, this will take a while. You can
3033 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3034 environment variable to the script, i. e. to use the ELDK cross tools
3037 CROSS_COMPILE=ppc_8xx- MAKEALL
3039 or to build on a native PowerPC system you can type
3041 CROSS_COMPILE=' ' MAKEALL
3043 When using the MAKEALL script, the default behaviour is to build
3044 U-Boot in the source directory. This location can be changed by
3045 setting the BUILD_DIR environment variable. Also, for each target
3046 built, the MAKEALL script saves two log files (<target>.ERR and
3047 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3048 location can be changed by setting the MAKEALL_LOGDIR environment
3049 variable. For example:
3051 export BUILD_DIR=/tmp/build
3052 export MAKEALL_LOGDIR=/tmp/log
3053 CROSS_COMPILE=ppc_8xx- MAKEALL
3055 With the above settings build objects are saved in the /tmp/build,
3056 log files are saved in the /tmp/log and the source tree remains clean
3057 during the whole build process.
3060 See also "U-Boot Porting Guide" below.
3063 Monitor Commands - Overview:
3064 ============================
3066 go - start application at address 'addr'
3067 run - run commands in an environment variable
3068 bootm - boot application image from memory
3069 bootp - boot image via network using BootP/TFTP protocol
3070 tftpboot- boot image via network using TFTP protocol
3071 and env variables "ipaddr" and "serverip"
3072 (and eventually "gatewayip")
3073 rarpboot- boot image via network using RARP/TFTP protocol
3074 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3075 loads - load S-Record file over serial line
3076 loadb - load binary file over serial line (kermit mode)
3078 mm - memory modify (auto-incrementing)
3079 nm - memory modify (constant address)
3080 mw - memory write (fill)
3082 cmp - memory compare
3083 crc32 - checksum calculation
3084 i2c - I2C sub-system
3085 sspi - SPI utility commands
3086 base - print or set address offset
3087 printenv- print environment variables
3088 setenv - set environment variables
3089 saveenv - save environment variables to persistent storage
3090 protect - enable or disable FLASH write protection
3091 erase - erase FLASH memory
3092 flinfo - print FLASH memory information
3093 bdinfo - print Board Info structure
3094 iminfo - print header information for application image
3095 coninfo - print console devices and informations
3096 ide - IDE sub-system
3097 loop - infinite loop on address range
3098 loopw - infinite write loop on address range
3099 mtest - simple RAM test
3100 icache - enable or disable instruction cache
3101 dcache - enable or disable data cache
3102 reset - Perform RESET of the CPU
3103 echo - echo args to console
3104 version - print monitor version
3105 help - print online help
3106 ? - alias for 'help'
3109 Monitor Commands - Detailed Description:
3110 ========================================
3114 For now: just type "help <command>".
3117 Environment Variables:
3118 ======================
3120 U-Boot supports user configuration using Environment Variables which
3121 can be made persistent by saving to Flash memory.
3123 Environment Variables are set using "setenv", printed using
3124 "printenv", and saved to Flash using "saveenv". Using "setenv"
3125 without a value can be used to delete a variable from the
3126 environment. As long as you don't save the environment you are
3127 working with an in-memory copy. In case the Flash area containing the
3128 environment is erased by accident, a default environment is provided.
3130 Some configuration options can be set using Environment Variables.
3132 List of environment variables (most likely not complete):
3134 baudrate - see CONFIG_BAUDRATE
3136 bootdelay - see CONFIG_BOOTDELAY
3138 bootcmd - see CONFIG_BOOTCOMMAND
3140 bootargs - Boot arguments when booting an RTOS image
3142 bootfile - Name of the image to load with TFTP
3144 bootm_low - Memory range available for image processing in the bootm
3145 command can be restricted. This variable is given as
3146 a hexadecimal number and defines lowest address allowed
3147 for use by the bootm command. See also "bootm_size"
3148 environment variable. Address defined by "bootm_low" is
3149 also the base of the initial memory mapping for the Linux
3150 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
3152 bootm_size - Memory range available for image processing in the bootm
3153 command can be restricted. This variable is given as
3154 a hexadecimal number and defines the size of the region
3155 allowed for use by the bootm command. See also "bootm_low"
3156 environment variable.
3158 updatefile - Location of the software update file on a TFTP server, used
3159 by the automatic software update feature. Please refer to
3160 documentation in doc/README.update for more details.
3162 autoload - if set to "no" (any string beginning with 'n'),
3163 "bootp" will just load perform a lookup of the
3164 configuration from the BOOTP server, but not try to
3165 load any image using TFTP
3167 autostart - if set to "yes", an image loaded using the "bootp",
3168 "rarpboot", "tftpboot" or "diskboot" commands will
3169 be automatically started (by internally calling
3172 If set to "no", a standalone image passed to the
3173 "bootm" command will be copied to the load address
3174 (and eventually uncompressed), but NOT be started.
3175 This can be used to load and uncompress arbitrary
3178 i2cfast - (PPC405GP|PPC405EP only)
3179 if set to 'y' configures Linux I2C driver for fast
3180 mode (400kHZ). This environment variable is used in
3181 initialization code. So, for changes to be effective
3182 it must be saved and board must be reset.
3184 initrd_high - restrict positioning of initrd images:
3185 If this variable is not set, initrd images will be
3186 copied to the highest possible address in RAM; this
3187 is usually what you want since it allows for
3188 maximum initrd size. If for some reason you want to
3189 make sure that the initrd image is loaded below the
3190 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3191 variable to a value of "no" or "off" or "0".
3192 Alternatively, you can set it to a maximum upper
3193 address to use (U-Boot will still check that it
3194 does not overwrite the U-Boot stack and data).
3196 For instance, when you have a system with 16 MB
3197 RAM, and want to reserve 4 MB from use by Linux,
3198 you can do this by adding "mem=12M" to the value of
3199 the "bootargs" variable. However, now you must make
3200 sure that the initrd image is placed in the first
3201 12 MB as well - this can be done with
3203 setenv initrd_high 00c00000
3205 If you set initrd_high to 0xFFFFFFFF, this is an
3206 indication to U-Boot that all addresses are legal
3207 for the Linux kernel, including addresses in flash
3208 memory. In this case U-Boot will NOT COPY the
3209 ramdisk at all. This may be useful to reduce the
3210 boot time on your system, but requires that this
3211 feature is supported by your Linux kernel.
3213 ipaddr - IP address; needed for tftpboot command
3215 loadaddr - Default load address for commands like "bootp",
3216 "rarpboot", "tftpboot", "loadb" or "diskboot"
3218 loads_echo - see CONFIG_LOADS_ECHO
3220 serverip - TFTP server IP address; needed for tftpboot command
3222 bootretry - see CONFIG_BOOT_RETRY_TIME
3224 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3226 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3228 ethprime - When CONFIG_NET_MULTI is enabled controls which
3229 interface is used first.
3231 ethact - When CONFIG_NET_MULTI is enabled controls which
3232 interface is currently active. For example you
3233 can do the following
3235 => setenv ethact FEC
3236 => ping 192.168.0.1 # traffic sent on FEC
3237 => setenv ethact SCC
3238 => ping 10.0.0.1 # traffic sent on SCC
3240 ethrotate - When set to "no" U-Boot does not go through all
3241 available network interfaces.
3242 It just stays at the currently selected interface.
3244 netretry - When set to "no" each network operation will
3245 either succeed or fail without retrying.
3246 When set to "once" the network operation will
3247 fail when all the available network interfaces
3248 are tried once without success.
3249 Useful on scripts which control the retry operation
3252 npe_ucode - set load address for the NPE microcode
3254 tftpsrcport - If this is set, the value is used for TFTP's
3257 tftpdstport - If this is set, the value is used for TFTP's UDP
3258 destination port instead of the Well Know Port 69.
3260 tftpblocksize - Block size to use for TFTP transfers; if not set,
3261 we use the TFTP server's default block size
3263 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3264 seconds, minimum value is 1000 = 1 second). Defines
3265 when a packet is considered to be lost so it has to
3266 be retransmitted. The default is 5000 = 5 seconds.
3267 Lowering this value may make downloads succeed
3268 faster in networks with high packet loss rates or
3269 with unreliable TFTP servers.
3271 vlan - When set to a value < 4095 the traffic over
3272 Ethernet is encapsulated/received over 802.1q
3275 The following environment variables may be used and automatically
3276 updated by the network boot commands ("bootp" and "rarpboot"),
3277 depending the information provided by your boot server:
3279 bootfile - see above
3280 dnsip - IP address of your Domain Name Server
3281 dnsip2 - IP address of your secondary Domain Name Server
3282 gatewayip - IP address of the Gateway (Router) to use
3283 hostname - Target hostname
3285 netmask - Subnet Mask
3286 rootpath - Pathname of the root filesystem on the NFS server
3287 serverip - see above
3290 There are two special Environment Variables:
3292 serial# - contains hardware identification information such
3293 as type string and/or serial number
3294 ethaddr - Ethernet address
3296 These variables can be set only once (usually during manufacturing of
3297 the board). U-Boot refuses to delete or overwrite these variables
3298 once they have been set once.
3301 Further special Environment Variables:
3303 ver - Contains the U-Boot version string as printed
3304 with the "version" command. This variable is
3305 readonly (see CONFIG_VERSION_VARIABLE).
3308 Please note that changes to some configuration parameters may take
3309 only effect after the next boot (yes, that's just like Windoze :-).
3312 Command Line Parsing:
3313 =====================
3315 There are two different command line parsers available with U-Boot:
3316 the old "simple" one, and the much more powerful "hush" shell:
3318 Old, simple command line parser:
3319 --------------------------------
3321 - supports environment variables (through setenv / saveenv commands)
3322 - several commands on one line, separated by ';'
3323 - variable substitution using "... ${name} ..." syntax
3324 - special characters ('$', ';') can be escaped by prefixing with '\',
3326 setenv bootcmd bootm \${address}
3327 - You can also escape text by enclosing in single apostrophes, for example:
3328 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3333 - similar to Bourne shell, with control structures like
3334 if...then...else...fi, for...do...done; while...do...done,
3335 until...do...done, ...
3336 - supports environment ("global") variables (through setenv / saveenv
3337 commands) and local shell variables (through standard shell syntax
3338 "name=value"); only environment variables can be used with "run"
3344 (1) If a command line (or an environment variable executed by a "run"
3345 command) contains several commands separated by semicolon, and
3346 one of these commands fails, then the remaining commands will be
3349 (2) If you execute several variables with one call to run (i. e.
3350 calling run with a list of variables as arguments), any failing
3351 command will cause "run" to terminate, i. e. the remaining
3352 variables are not executed.
3354 Note for Redundant Ethernet Interfaces:
3355 =======================================
3357 Some boards come with redundant Ethernet interfaces; U-Boot supports
3358 such configurations and is capable of automatic selection of a
3359 "working" interface when needed. MAC assignment works as follows:
3361 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3362 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3363 "eth1addr" (=>eth1), "eth2addr", ...
3365 If the network interface stores some valid MAC address (for instance
3366 in SROM), this is used as default address if there is NO correspon-
3367 ding setting in the environment; if the corresponding environment
3368 variable is set, this overrides the settings in the card; that means:
3370 o If the SROM has a valid MAC address, and there is no address in the
3371 environment, the SROM's address is used.
3373 o If there is no valid address in the SROM, and a definition in the
3374 environment exists, then the value from the environment variable is
3377 o If both the SROM and the environment contain a MAC address, and
3378 both addresses are the same, this MAC address is used.
3380 o If both the SROM and the environment contain a MAC address, and the
3381 addresses differ, the value from the environment is used and a
3384 o If neither SROM nor the environment contain a MAC address, an error
3387 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3388 will be programmed into hardware as part of the initialization process. This
3389 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3390 The naming convention is as follows:
3391 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3396 U-Boot is capable of booting (and performing other auxiliary operations on)
3397 images in two formats:
3399 New uImage format (FIT)
3400 -----------------------
3402 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3403 to Flattened Device Tree). It allows the use of images with multiple
3404 components (several kernels, ramdisks, etc.), with contents protected by
3405 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3411 Old image format is based on binary files which can be basically anything,
3412 preceded by a special header; see the definitions in include/image.h for
3413 details; basically, the header defines the following image properties:
3415 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3416 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3417 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3418 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3420 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3421 IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3422 Currently supported: ARM, AVR32, Intel x86, MIPS, Nios II, PowerPC).
3423 * Compression Type (uncompressed, gzip, bzip2)
3429 The header is marked by a special Magic Number, and both the header
3430 and the data portions of the image are secured against corruption by
3437 Although U-Boot should support any OS or standalone application
3438 easily, the main focus has always been on Linux during the design of
3441 U-Boot includes many features that so far have been part of some
3442 special "boot loader" code within the Linux kernel. Also, any
3443 "initrd" images to be used are no longer part of one big Linux image;
3444 instead, kernel and "initrd" are separate images. This implementation
3445 serves several purposes:
3447 - the same features can be used for other OS or standalone
3448 applications (for instance: using compressed images to reduce the
3449 Flash memory footprint)
3451 - it becomes much easier to port new Linux kernel versions because
3452 lots of low-level, hardware dependent stuff are done by U-Boot
3454 - the same Linux kernel image can now be used with different "initrd"
3455 images; of course this also means that different kernel images can
3456 be run with the same "initrd". This makes testing easier (you don't
3457 have to build a new "zImage.initrd" Linux image when you just
3458 change a file in your "initrd"). Also, a field-upgrade of the
3459 software is easier now.
3465 Porting Linux to U-Boot based systems:
3466 ---------------------------------------
3468 U-Boot cannot save you from doing all the necessary modifications to
3469 configure the Linux device drivers for use with your target hardware
3470 (no, we don't intend to provide a full virtual machine interface to
3473 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3475 Just make sure your machine specific header file (for instance
3476 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3477 Information structure as we define in include/asm-<arch>/u-boot.h,
3478 and make sure that your definition of IMAP_ADDR uses the same value
3479 as your U-Boot configuration in CONFIG_SYS_IMMR.
3482 Configuring the Linux kernel:
3483 -----------------------------
3485 No specific requirements for U-Boot. Make sure you have some root
3486 device (initial ramdisk, NFS) for your target system.
3489 Building a Linux Image:
3490 -----------------------
3492 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3493 not used. If you use recent kernel source, a new build target
3494 "uImage" will exist which automatically builds an image usable by
3495 U-Boot. Most older kernels also have support for a "pImage" target,
3496 which was introduced for our predecessor project PPCBoot and uses a
3497 100% compatible format.
3506 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3507 encapsulate a compressed Linux kernel image with header information,
3508 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3510 * build a standard "vmlinux" kernel image (in ELF binary format):
3512 * convert the kernel into a raw binary image:
3514 ${CROSS_COMPILE}-objcopy -O binary \
3515 -R .note -R .comment \
3516 -S vmlinux linux.bin
3518 * compress the binary image:
3522 * package compressed binary image for U-Boot:
3524 mkimage -A ppc -O linux -T kernel -C gzip \
3525 -a 0 -e 0 -n "Linux Kernel Image" \
3526 -d linux.bin.gz uImage
3529 The "mkimage" tool can also be used to create ramdisk images for use
3530 with U-Boot, either separated from the Linux kernel image, or
3531 combined into one file. "mkimage" encapsulates the images with a 64
3532 byte header containing information about target architecture,
3533 operating system, image type, compression method, entry points, time
3534 stamp, CRC32 checksums, etc.
3536 "mkimage" can be called in two ways: to verify existing images and
3537 print the header information, or to build new images.
3539 In the first form (with "-l" option) mkimage lists the information
3540 contained in the header of an existing U-Boot image; this includes
3541 checksum verification:
3543 tools/mkimage -l image
3544 -l ==> list image header information
3546 The second form (with "-d" option) is used to build a U-Boot image
3547 from a "data file" which is used as image payload:
3549 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3550 -n name -d data_file image
3551 -A ==> set architecture to 'arch'
3552 -O ==> set operating system to 'os'
3553 -T ==> set image type to 'type'
3554 -C ==> set compression type 'comp'
3555 -a ==> set load address to 'addr' (hex)
3556 -e ==> set entry point to 'ep' (hex)
3557 -n ==> set image name to 'name'
3558 -d ==> use image data from 'datafile'
3560 Right now, all Linux kernels for PowerPC systems use the same load
3561 address (0x00000000), but the entry point address depends on the
3564 - 2.2.x kernels have the entry point at 0x0000000C,
3565 - 2.3.x and later kernels have the entry point at 0x00000000.
3567 So a typical call to build a U-Boot image would read:
3569 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3570 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3571 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3572 > examples/uImage.TQM850L
3573 Image Name: 2.4.4 kernel for TQM850L
3574 Created: Wed Jul 19 02:34:59 2000
3575 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3576 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3577 Load Address: 0x00000000
3578 Entry Point: 0x00000000
3580 To verify the contents of the image (or check for corruption):
3582 -> tools/mkimage -l examples/uImage.TQM850L
3583 Image Name: 2.4.4 kernel for TQM850L
3584 Created: Wed Jul 19 02:34:59 2000
3585 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3586 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3587 Load Address: 0x00000000
3588 Entry Point: 0x00000000
3590 NOTE: for embedded systems where boot time is critical you can trade
3591 speed for memory and install an UNCOMPRESSED image instead: this
3592 needs more space in Flash, but boots much faster since it does not
3593 need to be uncompressed:
3595 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3596 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3597 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3598 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3599 > examples/uImage.TQM850L-uncompressed
3600 Image Name: 2.4.4 kernel for TQM850L
3601 Created: Wed Jul 19 02:34:59 2000
3602 Image Type: PowerPC Linux Kernel Image (uncompressed)
3603 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3604 Load Address: 0x00000000
3605 Entry Point: 0x00000000
3608 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3609 when your kernel is intended to use an initial ramdisk:
3611 -> tools/mkimage -n 'Simple Ramdisk Image' \
3612 > -A ppc -O linux -T ramdisk -C gzip \
3613 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3614 Image Name: Simple Ramdisk Image
3615 Created: Wed Jan 12 14:01:50 2000
3616 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3617 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3618 Load Address: 0x00000000
3619 Entry Point: 0x00000000
3622 Installing a Linux Image:
3623 -------------------------
3625 To downloading a U-Boot image over the serial (console) interface,
3626 you must convert the image to S-Record format:
3628 objcopy -I binary -O srec examples/image examples/image.srec
3630 The 'objcopy' does not understand the information in the U-Boot
3631 image header, so the resulting S-Record file will be relative to
3632 address 0x00000000. To load it to a given address, you need to
3633 specify the target address as 'offset' parameter with the 'loads'
3636 Example: install the image to address 0x40100000 (which on the
3637 TQM8xxL is in the first Flash bank):
3639 => erase 40100000 401FFFFF
3645 ## Ready for S-Record download ...
3646 ~>examples/image.srec
3647 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3649 15989 15990 15991 15992
3650 [file transfer complete]
3652 ## Start Addr = 0x00000000
3655 You can check the success of the download using the 'iminfo' command;
3656 this includes a checksum verification so you can be sure no data
3657 corruption happened:
3661 ## Checking Image at 40100000 ...
3662 Image Name: 2.2.13 for initrd on TQM850L
3663 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3664 Data Size: 335725 Bytes = 327 kB = 0 MB
3665 Load Address: 00000000
3666 Entry Point: 0000000c
3667 Verifying Checksum ... OK
3673 The "bootm" command is used to boot an application that is stored in
3674 memory (RAM or Flash). In case of a Linux kernel image, the contents
3675 of the "bootargs" environment variable is passed to the kernel as
3676 parameters. You can check and modify this variable using the
3677 "printenv" and "setenv" commands:
3680 => printenv bootargs
3681 bootargs=root=/dev/ram
3683 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3685 => printenv bootargs
3686 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3689 ## Booting Linux kernel at 40020000 ...
3690 Image Name: 2.2.13 for NFS on TQM850L
3691 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3692 Data Size: 381681 Bytes = 372 kB = 0 MB
3693 Load Address: 00000000
3694 Entry Point: 0000000c
3695 Verifying Checksum ... OK
3696 Uncompressing Kernel Image ... OK
3697 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
3698 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3699 time_init: decrementer frequency = 187500000/60
3700 Calibrating delay loop... 49.77 BogoMIPS
3701 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3704 If you want to boot a Linux kernel with initial RAM disk, you pass
3705 the memory addresses of both the kernel and the initrd image (PPBCOOT
3706 format!) to the "bootm" command:
3708 => imi 40100000 40200000
3710 ## Checking Image at 40100000 ...
3711 Image Name: 2.2.13 for initrd on TQM850L
3712 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3713 Data Size: 335725 Bytes = 327 kB = 0 MB
3714 Load Address: 00000000
3715 Entry Point: 0000000c
3716 Verifying Checksum ... OK
3718 ## Checking Image at 40200000 ...
3719 Image Name: Simple Ramdisk Image
3720 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3721 Data Size: 566530 Bytes = 553 kB = 0 MB
3722 Load Address: 00000000
3723 Entry Point: 00000000
3724 Verifying Checksum ... OK
3726 => bootm 40100000 40200000
3727 ## Booting Linux kernel at 40100000 ...
3728 Image Name: 2.2.13 for initrd on TQM850L
3729 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3730 Data Size: 335725 Bytes = 327 kB = 0 MB
3731 Load Address: 00000000
3732 Entry Point: 0000000c
3733 Verifying Checksum ... OK
3734 Uncompressing Kernel Image ... OK
3735 ## Loading RAMDisk Image at 40200000 ...
3736 Image Name: Simple Ramdisk Image
3737 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3738 Data Size: 566530 Bytes = 553 kB = 0 MB
3739 Load Address: 00000000
3740 Entry Point: 00000000
3741 Verifying Checksum ... OK
3742 Loading Ramdisk ... OK
3743 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
3744 Boot arguments: root=/dev/ram
3745 time_init: decrementer frequency = 187500000/60
3746 Calibrating delay loop... 49.77 BogoMIPS
3748 RAMDISK: Compressed image found at block 0
3749 VFS: Mounted root (ext2 filesystem).
3753 Boot Linux and pass a flat device tree:
3756 First, U-Boot must be compiled with the appropriate defines. See the section
3757 titled "Linux Kernel Interface" above for a more in depth explanation. The
3758 following is an example of how to start a kernel and pass an updated
3764 oft=oftrees/mpc8540ads.dtb
3765 => tftp $oftaddr $oft
3766 Speed: 1000, full duplex
3768 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3769 Filename 'oftrees/mpc8540ads.dtb'.
3770 Load address: 0x300000
3773 Bytes transferred = 4106 (100a hex)
3774 => tftp $loadaddr $bootfile
3775 Speed: 1000, full duplex
3777 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3779 Load address: 0x200000
3780 Loading:############
3782 Bytes transferred = 1029407 (fb51f hex)
3787 => bootm $loadaddr - $oftaddr
3788 ## Booting image at 00200000 ...
3789 Image Name: Linux-2.6.17-dirty
3790 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3791 Data Size: 1029343 Bytes = 1005.2 kB
3792 Load Address: 00000000
3793 Entry Point: 00000000
3794 Verifying Checksum ... OK
3795 Uncompressing Kernel Image ... OK
3796 Booting using flat device tree at 0x300000
3797 Using MPC85xx ADS machine description
3798 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3802 More About U-Boot Image Types:
3803 ------------------------------
3805 U-Boot supports the following image types:
3807 "Standalone Programs" are directly runnable in the environment
3808 provided by U-Boot; it is expected that (if they behave
3809 well) you can continue to work in U-Boot after return from
3810 the Standalone Program.
3811 "OS Kernel Images" are usually images of some Embedded OS which
3812 will take over control completely. Usually these programs
3813 will install their own set of exception handlers, device
3814 drivers, set up the MMU, etc. - this means, that you cannot
3815 expect to re-enter U-Boot except by resetting the CPU.
3816 "RAMDisk Images" are more or less just data blocks, and their
3817 parameters (address, size) are passed to an OS kernel that is
3819 "Multi-File Images" contain several images, typically an OS
3820 (Linux) kernel image and one or more data images like
3821 RAMDisks. This construct is useful for instance when you want
3822 to boot over the network using BOOTP etc., where the boot
3823 server provides just a single image file, but you want to get
3824 for instance an OS kernel and a RAMDisk image.
3826 "Multi-File Images" start with a list of image sizes, each
3827 image size (in bytes) specified by an "uint32_t" in network
3828 byte order. This list is terminated by an "(uint32_t)0".
3829 Immediately after the terminating 0 follow the images, one by
3830 one, all aligned on "uint32_t" boundaries (size rounded up to
3831 a multiple of 4 bytes).
3833 "Firmware Images" are binary images containing firmware (like
3834 U-Boot or FPGA images) which usually will be programmed to
3837 "Script files" are command sequences that will be executed by
3838 U-Boot's command interpreter; this feature is especially
3839 useful when you configure U-Boot to use a real shell (hush)
3840 as command interpreter.
3846 One of the features of U-Boot is that you can dynamically load and
3847 run "standalone" applications, which can use some resources of
3848 U-Boot like console I/O functions or interrupt services.
3850 Two simple examples are included with the sources:
3855 'examples/hello_world.c' contains a small "Hello World" Demo
3856 application; it is automatically compiled when you build U-Boot.
3857 It's configured to run at address 0x00040004, so you can play with it
3861 ## Ready for S-Record download ...
3862 ~>examples/hello_world.srec
3863 1 2 3 4 5 6 7 8 9 10 11 ...
3864 [file transfer complete]
3866 ## Start Addr = 0x00040004
3868 => go 40004 Hello World! This is a test.
3869 ## Starting application at 0x00040004 ...
3880 Hit any key to exit ...
3882 ## Application terminated, rc = 0x0
3884 Another example, which demonstrates how to register a CPM interrupt
3885 handler with the U-Boot code, can be found in 'examples/timer.c'.
3886 Here, a CPM timer is set up to generate an interrupt every second.
3887 The interrupt service routine is trivial, just printing a '.'
3888 character, but this is just a demo program. The application can be
3889 controlled by the following keys:
3891 ? - print current values og the CPM Timer registers
3892 b - enable interrupts and start timer
3893 e - stop timer and disable interrupts
3894 q - quit application
3897 ## Ready for S-Record download ...
3898 ~>examples/timer.srec
3899 1 2 3 4 5 6 7 8 9 10 11 ...
3900 [file transfer complete]
3902 ## Start Addr = 0x00040004
3905 ## Starting application at 0x00040004 ...
3908 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3911 [q, b, e, ?] Set interval 1000000 us
3914 [q, b, e, ?] ........
3915 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3918 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3921 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3924 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3926 [q, b, e, ?] ...Stopping timer
3928 [q, b, e, ?] ## Application terminated, rc = 0x0
3934 Over time, many people have reported problems when trying to use the
3935 "minicom" terminal emulation program for serial download. I (wd)
3936 consider minicom to be broken, and recommend not to use it. Under
3937 Unix, I recommend to use C-Kermit for general purpose use (and
3938 especially for kermit binary protocol download ("loadb" command), and
3939 use "cu" for S-Record download ("loads" command).
3941 Nevertheless, if you absolutely want to use it try adding this
3942 configuration to your "File transfer protocols" section:
3944 Name Program Name U/D FullScr IO-Red. Multi
3945 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3946 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3952 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3953 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3955 Building requires a cross environment; it is known to work on
3956 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3957 need gmake since the Makefiles are not compatible with BSD make).
3958 Note that the cross-powerpc package does not install include files;
3959 attempting to build U-Boot will fail because <machine/ansi.h> is
3960 missing. This file has to be installed and patched manually:
3962 # cd /usr/pkg/cross/powerpc-netbsd/include
3964 # ln -s powerpc machine
3965 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3966 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3968 Native builds *don't* work due to incompatibilities between native
3969 and U-Boot include files.
3971 Booting assumes that (the first part of) the image booted is a
3972 stage-2 loader which in turn loads and then invokes the kernel
3973 proper. Loader sources will eventually appear in the NetBSD source
3974 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3975 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3978 Implementation Internals:
3979 =========================
3981 The following is not intended to be a complete description of every
3982 implementation detail. However, it should help to understand the
3983 inner workings of U-Boot and make it easier to port it to custom
3987 Initial Stack, Global Data:
3988 ---------------------------
3990 The implementation of U-Boot is complicated by the fact that U-Boot
3991 starts running out of ROM (flash memory), usually without access to
3992 system RAM (because the memory controller is not initialized yet).
3993 This means that we don't have writable Data or BSS segments, and BSS
3994 is not initialized as zero. To be able to get a C environment working
3995 at all, we have to allocate at least a minimal stack. Implementation
3996 options for this are defined and restricted by the CPU used: Some CPU
3997 models provide on-chip memory (like the IMMR area on MPC8xx and
3998 MPC826x processors), on others (parts of) the data cache can be
3999 locked as (mis-) used as memory, etc.
4001 Chris Hallinan posted a good summary of these issues to the
4002 U-Boot mailing list:
4004 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4005 From: "Chris Hallinan" <clh@net1plus.com>
4006 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4009 Correct me if I'm wrong, folks, but the way I understand it
4010 is this: Using DCACHE as initial RAM for Stack, etc, does not
4011 require any physical RAM backing up the cache. The cleverness
4012 is that the cache is being used as a temporary supply of
4013 necessary storage before the SDRAM controller is setup. It's
4014 beyond the scope of this list to explain the details, but you
4015 can see how this works by studying the cache architecture and
4016 operation in the architecture and processor-specific manuals.
4018 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4019 is another option for the system designer to use as an
4020 initial stack/RAM area prior to SDRAM being available. Either
4021 option should work for you. Using CS 4 should be fine if your
4022 board designers haven't used it for something that would
4023 cause you grief during the initial boot! It is frequently not
4026 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4027 with your processor/board/system design. The default value
4028 you will find in any recent u-boot distribution in
4029 walnut.h should work for you. I'd set it to a value larger
4030 than your SDRAM module. If you have a 64MB SDRAM module, set
4031 it above 400_0000. Just make sure your board has no resources
4032 that are supposed to respond to that address! That code in
4033 start.S has been around a while and should work as is when
4034 you get the config right.
4039 It is essential to remember this, since it has some impact on the C
4040 code for the initialization procedures:
4042 * Initialized global data (data segment) is read-only. Do not attempt
4045 * Do not use any uninitialized global data (or implicitely initialized
4046 as zero data - BSS segment) at all - this is undefined, initiali-
4047 zation is performed later (when relocating to RAM).
4049 * Stack space is very limited. Avoid big data buffers or things like
4052 Having only the stack as writable memory limits means we cannot use
4053 normal global data to share information beween the code. But it
4054 turned out that the implementation of U-Boot can be greatly
4055 simplified by making a global data structure (gd_t) available to all
4056 functions. We could pass a pointer to this data as argument to _all_
4057 functions, but this would bloat the code. Instead we use a feature of
4058 the GCC compiler (Global Register Variables) to share the data: we
4059 place a pointer (gd) to the global data into a register which we
4060 reserve for this purpose.
4062 When choosing a register for such a purpose we are restricted by the
4063 relevant (E)ABI specifications for the current architecture, and by
4064 GCC's implementation.
4066 For PowerPC, the following registers have specific use:
4068 R2: reserved for system use
4069 R3-R4: parameter passing and return values
4070 R5-R10: parameter passing
4071 R13: small data area pointer
4075 (U-Boot also uses R12 as internal GOT pointer. r12
4076 is a volatile register so r12 needs to be reset when
4077 going back and forth between asm and C)
4079 ==> U-Boot will use R2 to hold a pointer to the global data
4081 Note: on PPC, we could use a static initializer (since the
4082 address of the global data structure is known at compile time),
4083 but it turned out that reserving a register results in somewhat
4084 smaller code - although the code savings are not that big (on
4085 average for all boards 752 bytes for the whole U-Boot image,
4086 624 text + 127 data).
4088 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4089 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4091 ==> U-Boot will use P3 to hold a pointer to the global data
4093 On ARM, the following registers are used:
4095 R0: function argument word/integer result
4096 R1-R3: function argument word
4098 R10: stack limit (used only if stack checking if enabled)
4099 R11: argument (frame) pointer
4100 R12: temporary workspace
4103 R15: program counter
4105 ==> U-Boot will use R8 to hold a pointer to the global data
4107 On Nios II, the ABI is documented here:
4108 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4110 ==> U-Boot will use gp to hold a pointer to the global data
4112 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4113 to access small data sections, so gp is free.
4115 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4116 or current versions of GCC may "optimize" the code too much.
4121 U-Boot runs in system state and uses physical addresses, i.e. the
4122 MMU is not used either for address mapping nor for memory protection.
4124 The available memory is mapped to fixed addresses using the memory
4125 controller. In this process, a contiguous block is formed for each
4126 memory type (Flash, SDRAM, SRAM), even when it consists of several
4127 physical memory banks.
4129 U-Boot is installed in the first 128 kB of the first Flash bank (on
4130 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4131 booting and sizing and initializing DRAM, the code relocates itself
4132 to the upper end of DRAM. Immediately below the U-Boot code some
4133 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4134 configuration setting]. Below that, a structure with global Board
4135 Info data is placed, followed by the stack (growing downward).
4137 Additionally, some exception handler code is copied to the low 8 kB
4138 of DRAM (0x00000000 ... 0x00001FFF).
4140 So a typical memory configuration with 16 MB of DRAM could look like
4143 0x0000 0000 Exception Vector code
4146 0x0000 2000 Free for Application Use
4152 0x00FB FF20 Monitor Stack (Growing downward)
4153 0x00FB FFAC Board Info Data and permanent copy of global data
4154 0x00FC 0000 Malloc Arena
4157 0x00FE 0000 RAM Copy of Monitor Code
4158 ... eventually: LCD or video framebuffer
4159 ... eventually: pRAM (Protected RAM - unchanged by reset)
4160 0x00FF FFFF [End of RAM]
4163 System Initialization:
4164 ----------------------
4166 In the reset configuration, U-Boot starts at the reset entry point
4167 (on most PowerPC systems at address 0x00000100). Because of the reset
4168 configuration for CS0# this is a mirror of the onboard Flash memory.
4169 To be able to re-map memory U-Boot then jumps to its link address.
4170 To be able to implement the initialization code in C, a (small!)
4171 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4172 which provide such a feature like MPC8xx or MPC8260), or in a locked
4173 part of the data cache. After that, U-Boot initializes the CPU core,
4174 the caches and the SIU.
4176 Next, all (potentially) available memory banks are mapped using a
4177 preliminary mapping. For example, we put them on 512 MB boundaries
4178 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4179 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4180 programmed for SDRAM access. Using the temporary configuration, a
4181 simple memory test is run that determines the size of the SDRAM
4184 When there is more than one SDRAM bank, and the banks are of
4185 different size, the largest is mapped first. For equal size, the first
4186 bank (CS2#) is mapped first. The first mapping is always for address
4187 0x00000000, with any additional banks following immediately to create
4188 contiguous memory starting from 0.
4190 Then, the monitor installs itself at the upper end of the SDRAM area
4191 and allocates memory for use by malloc() and for the global Board
4192 Info data; also, the exception vector code is copied to the low RAM
4193 pages, and the final stack is set up.
4195 Only after this relocation will you have a "normal" C environment;
4196 until that you are restricted in several ways, mostly because you are
4197 running from ROM, and because the code will have to be relocated to a
4201 U-Boot Porting Guide:
4202 ----------------------
4204 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4208 int main(int argc, char *argv[])
4210 sighandler_t no_more_time;
4212 signal(SIGALRM, no_more_time);
4213 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4215 if (available_money > available_manpower) {
4216 Pay consultant to port U-Boot;
4220 Download latest U-Boot source;
4222 Subscribe to u-boot mailing list;
4225 email("Hi, I am new to U-Boot, how do I get started?");
4228 Read the README file in the top level directory;
4229 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4230 Read applicable doc/*.README;
4231 Read the source, Luke;
4232 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4235 if (available_money > toLocalCurrency ($2500))
4238 Add a lot of aggravation and time;
4240 if (a similar board exists) { /* hopefully... */
4241 cp -a board/<similar> board/<myboard>
4242 cp include/configs/<similar>.h include/configs/<myboard>.h
4244 Create your own board support subdirectory;
4245 Create your own board include/configs/<myboard>.h file;
4247 Edit new board/<myboard> files
4248 Edit new include/configs/<myboard>.h
4253 Add / modify source code;
4257 email("Hi, I am having problems...");
4259 Send patch file to the U-Boot email list;
4260 if (reasonable critiques)
4261 Incorporate improvements from email list code review;
4263 Defend code as written;
4269 void no_more_time (int sig)
4278 All contributions to U-Boot should conform to the Linux kernel
4279 coding style; see the file "Documentation/CodingStyle" and the script
4280 "scripts/Lindent" in your Linux kernel source directory. In sources
4281 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4282 spaces before parameters to function calls) is actually used.
4284 Source files originating from a different project (for example the
4285 MTD subsystem) are generally exempt from these guidelines and are not
4286 reformated to ease subsequent migration to newer versions of those
4289 Please note that U-Boot is implemented in C (and to some small parts in
4290 Assembler); no C++ is used, so please do not use C++ style comments (//)
4293 Please also stick to the following formatting rules:
4294 - remove any trailing white space
4295 - use TAB characters for indentation, not spaces
4296 - make sure NOT to use DOS '\r\n' line feeds
4297 - do not add more than 2 empty lines to source files
4298 - do not add trailing empty lines to source files
4300 Submissions which do not conform to the standards may be returned
4301 with a request to reformat the changes.
4307 Since the number of patches for U-Boot is growing, we need to
4308 establish some rules. Submissions which do not conform to these rules
4309 may be rejected, even when they contain important and valuable stuff.
4311 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4313 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4314 see http://lists.denx.de/mailman/listinfo/u-boot
4316 When you send a patch, please include the following information with
4319 * For bug fixes: a description of the bug and how your patch fixes
4320 this bug. Please try to include a way of demonstrating that the
4321 patch actually fixes something.
4323 * For new features: a description of the feature and your
4326 * A CHANGELOG entry as plaintext (separate from the patch)
4328 * For major contributions, your entry to the CREDITS file
4330 * When you add support for a new board, don't forget to add this
4331 board to the MAKEALL script, too.
4333 * If your patch adds new configuration options, don't forget to
4334 document these in the README file.
4336 * The patch itself. If you are using git (which is *strongly*
4337 recommended) you can easily generate the patch using the
4338 "git-format-patch". If you then use "git-send-email" to send it to
4339 the U-Boot mailing list, you will avoid most of the common problems
4340 with some other mail clients.
4342 If you cannot use git, use "diff -purN OLD NEW". If your version of
4343 diff does not support these options, then get the latest version of
4346 The current directory when running this command shall be the parent
4347 directory of the U-Boot source tree (i. e. please make sure that
4348 your patch includes sufficient directory information for the
4351 We prefer patches as plain text. MIME attachments are discouraged,
4352 and compressed attachments must not be used.
4354 * If one logical set of modifications affects or creates several
4355 files, all these changes shall be submitted in a SINGLE patch file.
4357 * Changesets that contain different, unrelated modifications shall be
4358 submitted as SEPARATE patches, one patch per changeset.
4363 * Before sending the patch, run the MAKEALL script on your patched
4364 source tree and make sure that no errors or warnings are reported
4365 for any of the boards.
4367 * Keep your modifications to the necessary minimum: A patch
4368 containing several unrelated changes or arbitrary reformats will be
4369 returned with a request to re-formatting / split it.
4371 * If you modify existing code, make sure that your new code does not
4372 add to the memory footprint of the code ;-) Small is beautiful!
4373 When adding new features, these should compile conditionally only
4374 (using #ifdef), and the resulting code with the new feature
4375 disabled must not need more memory than the old code without your
4378 * Remember that there is a size limit of 100 kB per message on the
4379 u-boot mailing list. Bigger patches will be moderated. If they are
4380 reasonable and not too big, they will be acknowledged. But patches
4381 bigger than the size limit should be avoided.
projects / oweals / u-boot.git / blob