2 # (C) Copyright 2000 - 2008
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-users@lists.sourceforge.net>. There is also an archive of
64 previous traffic on the mailing list - please search the archive
65 before asking FAQ's. Please see
66 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
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. Ofifcial 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/UBoot
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 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 - board Board dependent files
142 - common Misc architecture independent functions
143 - cpu CPU specific files
144 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
145 - arm720t Files specific to ARM 720 CPUs
146 - arm920t Files specific to ARM 920 CPUs
147 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148 - imx Files specific to Freescale MC9328 i.MX CPUs
149 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
150 - arm925t Files specific to ARM 925 CPUs
151 - arm926ejs Files specific to ARM 926 CPUs
152 - arm1136 Files specific to ARM 1136 CPUs
153 - at32ap Files specific to Atmel AVR32 AP CPUs
154 - i386 Files specific to i386 CPUs
155 - ixp Files specific to Intel XScale IXP CPUs
156 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
157 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
158 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
159 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
160 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
161 - mips Files specific to MIPS CPUs
162 - mpc5xx Files specific to Freescale MPC5xx CPUs
163 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
164 - mpc8xx Files specific to Freescale MPC8xx CPUs
165 - mpc8220 Files specific to Freescale MPC8220 CPUs
166 - mpc824x Files specific to Freescale MPC824x CPUs
167 - mpc8260 Files specific to Freescale MPC8260 CPUs
168 - mpc85xx Files specific to Freescale MPC85xx CPUs
169 - nios Files specific to Altera NIOS CPUs
170 - nios2 Files specific to Altera Nios-II CPUs
171 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
172 - pxa Files specific to Intel XScale PXA CPUs
173 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
174 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
175 - disk Code for disk drive partition handling
176 - doc Documentation (don't expect too much)
177 - drivers Commonly used device drivers
178 - dtt Digital Thermometer and Thermostat drivers
179 - examples Example code for standalone applications, etc.
180 - include Header Files
181 - lib_arm Files generic to ARM architecture
182 - lib_avr32 Files generic to AVR32 architecture
183 - lib_generic Files generic to all architectures
184 - lib_i386 Files generic to i386 architecture
185 - lib_m68k Files generic to m68k architecture
186 - lib_mips Files generic to MIPS architecture
187 - lib_nios Files generic to NIOS architecture
188 - lib_ppc Files generic to PowerPC architecture
189 - libfdt Library files to support flattened device trees
190 - net Networking code
191 - post Power On Self Test
192 - rtc Real Time Clock drivers
193 - tools Tools to build S-Record or U-Boot images, etc.
195 Software Configuration:
196 =======================
198 Configuration is usually done using C preprocessor defines; the
199 rationale behind that is to avoid dead code whenever possible.
201 There are two classes of configuration variables:
203 * Configuration _OPTIONS_:
204 These are selectable by the user and have names beginning with
207 * Configuration _SETTINGS_:
208 These depend on the hardware etc. and should not be meddled with if
209 you don't know what you're doing; they have names beginning with
212 Later we will add a configuration tool - probably similar to or even
213 identical to what's used for the Linux kernel. Right now, we have to
214 do the configuration by hand, which means creating some symbolic
215 links and editing some configuration files. We use the TQM8xxL boards
219 Selection of Processor Architecture and Board Type:
220 ---------------------------------------------------
222 For all supported boards there are ready-to-use default
223 configurations available; just type "make <board_name>_config".
225 Example: For a TQM823L module type:
230 For the Cogent platform, you need to specify the cpu type as well;
231 e.g. "make cogent_mpc8xx_config". And also configure the cogent
232 directory according to the instructions in cogent/README.
235 Configuration Options:
236 ----------------------
238 Configuration depends on the combination of board and CPU type; all
239 such information is kept in a configuration file
240 "include/configs/<board_name>.h".
242 Example: For a TQM823L module, all configuration settings are in
243 "include/configs/TQM823L.h".
246 Many of the options are named exactly as the corresponding Linux
247 kernel configuration options. The intention is to make it easier to
248 build a config tool - later.
251 The following options need to be configured:
253 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
255 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
257 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
258 Define exactly one, e.g. CONFIG_ATSTK1002
260 - CPU Module Type: (if CONFIG_COGENT is defined)
261 Define exactly one of
263 --- FIXME --- not tested yet:
264 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
265 CONFIG_CMA287_23, CONFIG_CMA287_50
267 - Motherboard Type: (if CONFIG_COGENT is defined)
268 Define exactly one of
269 CONFIG_CMA101, CONFIG_CMA102
271 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
272 Define one or more of
275 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
276 Define one or more of
277 CONFIG_LCD_HEARTBEAT - update a character position on
278 the lcd display every second with
281 - Board flavour: (if CONFIG_MPC8260ADS is defined)
284 CFG_8260ADS - original MPC8260ADS
285 CFG_8266ADS - MPC8266ADS
286 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
287 CFG_8272ADS - MPC8272ADS
289 - MPC824X Family Member (if CONFIG_MPC824X is defined)
290 Define exactly one of
291 CONFIG_MPC8240, CONFIG_MPC8245
293 - 8xx CPU Options: (if using an MPC8xx cpu)
294 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
295 get_gclk_freq() cannot work
296 e.g. if there is no 32KHz
297 reference PIT/RTC clock
298 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
301 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
304 CONFIG_8xx_CPUCLK_DEFAULT
305 See doc/README.MPC866
309 Define this to measure the actual CPU clock instead
310 of relying on the correctness of the configured
311 values. Mostly useful for board bringup to make sure
312 the PLL is locked at the intended frequency. Note
313 that this requires a (stable) reference clock (32 kHz
314 RTC clock or CFG_8XX_XIN)
316 - Intel Monahans options:
317 CFG_MONAHANS_RUN_MODE_OSC_RATIO
319 Defines the Monahans run mode to oscillator
320 ratio. Valid values are 8, 16, 24, 31. The core
321 frequency is this value multiplied by 13 MHz.
323 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
325 Defines the Monahans turbo mode to oscillator
326 ratio. Valid values are 1 (default if undefined) and
327 2. The core frequency as calculated above is multiplied
330 - Linux Kernel Interface:
333 U-Boot stores all clock information in Hz
334 internally. For binary compatibility with older Linux
335 kernels (which expect the clocks passed in the
336 bd_info data to be in MHz) the environment variable
337 "clocks_in_mhz" can be defined so that U-Boot
338 converts clock data to MHZ before passing it to the
340 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
341 "clocks_in_mhz=1" is automatically included in the
344 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
346 When transfering memsize parameter to linux, some versions
347 expect it to be in bytes, others in MB.
348 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
350 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
352 New kernel versions are expecting firmware settings to be
353 passed using flattened device trees (based on open firmware
357 * New libfdt-based support
358 * Adds the "fdt" command
359 * The bootm command automatically updates the fdt
362 * Deprecated, see CONFIG_OF_LIBFDT
363 * Original ft_build.c-based support
364 * Automatically modifies the dft as part of the bootm command
365 * The environment variable "disable_of", when set,
366 disables this functionality.
368 OF_CPU - The proper name of the cpus node.
369 OF_SOC - The proper name of the soc node.
370 OF_TBCLK - The timebase frequency.
371 OF_STDOUT_PATH - The path to the console device
373 boards with QUICC Engines require OF_QE to set UCC mac addresses
375 CONFIG_OF_BOARD_SETUP
377 Board code has addition modification that it wants to make
378 to the flat device tree before handing it off to the kernel
382 This define fills in the correct boot cpu in the boot
383 param header, the default value is zero if undefined.
388 Define this if you want support for Amba PrimeCell PL010 UARTs.
392 Define this if you want support for Amba PrimeCell PL011 UARTs.
396 If you have Amba PrimeCell PL011 UARTs, set this variable to
397 the clock speed of the UARTs.
401 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
402 define this to a list of base addresses for each (supported)
403 port. See e.g. include/configs/versatile.h
407 Depending on board, define exactly one serial port
408 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
409 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
410 console by defining CONFIG_8xx_CONS_NONE
412 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
413 port routines must be defined elsewhere
414 (i.e. serial_init(), serial_getc(), ...)
417 Enables console device for a color framebuffer. Needs following
418 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
419 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
421 VIDEO_HW_RECTFILL graphic chip supports
424 VIDEO_HW_BITBLT graphic chip supports
425 bit-blit (cf. smiLynxEM)
426 VIDEO_VISIBLE_COLS visible pixel columns
428 VIDEO_VISIBLE_ROWS visible pixel rows
429 VIDEO_PIXEL_SIZE bytes per pixel
430 VIDEO_DATA_FORMAT graphic data format
431 (0-5, cf. cfb_console.c)
432 VIDEO_FB_ADRS framebuffer address
433 VIDEO_KBD_INIT_FCT keyboard int fct
434 (i.e. i8042_kbd_init())
435 VIDEO_TSTC_FCT test char fct
437 VIDEO_GETC_FCT get char fct
439 CONFIG_CONSOLE_CURSOR cursor drawing on/off
440 (requires blink timer
442 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
443 CONFIG_CONSOLE_TIME display time/date info in
445 (requires CONFIG_CMD_DATE)
446 CONFIG_VIDEO_LOGO display Linux logo in
448 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
449 linux_logo.h for logo.
450 Requires CONFIG_VIDEO_LOGO
451 CONFIG_CONSOLE_EXTRA_INFO
452 addional board info beside
455 When CONFIG_CFB_CONSOLE is defined, video console is
456 default i/o. Serial console can be forced with
457 environment 'console=serial'.
459 When CONFIG_SILENT_CONSOLE is defined, all console
460 messages (by U-Boot and Linux!) can be silenced with
461 the "silent" environment variable. See
462 doc/README.silent for more information.
465 CONFIG_BAUDRATE - in bps
466 Select one of the baudrates listed in
467 CFG_BAUDRATE_TABLE, see below.
468 CFG_BRGCLK_PRESCALE, baudrate prescale
470 - Interrupt driven serial port input:
471 CONFIG_SERIAL_SOFTWARE_FIFO
474 Use an interrupt handler for receiving data on the
475 serial port. It also enables using hardware handshake
476 (RTS/CTS) and UART's built-in FIFO. Set the number of
477 bytes the interrupt driven input buffer should have.
479 Leave undefined to disable this feature, including
480 disable the buffer and hardware handshake.
482 - Console UART Number:
486 If defined internal UART1 (and not UART0) is used
487 as default U-Boot console.
489 - Boot Delay: CONFIG_BOOTDELAY - in seconds
490 Delay before automatically booting the default image;
491 set to -1 to disable autoboot.
493 See doc/README.autoboot for these options that
494 work with CONFIG_BOOTDELAY. None are required.
495 CONFIG_BOOT_RETRY_TIME
496 CONFIG_BOOT_RETRY_MIN
497 CONFIG_AUTOBOOT_KEYED
498 CONFIG_AUTOBOOT_PROMPT
499 CONFIG_AUTOBOOT_DELAY_STR
500 CONFIG_AUTOBOOT_STOP_STR
501 CONFIG_AUTOBOOT_DELAY_STR2
502 CONFIG_AUTOBOOT_STOP_STR2
503 CONFIG_ZERO_BOOTDELAY_CHECK
504 CONFIG_RESET_TO_RETRY
508 Only needed when CONFIG_BOOTDELAY is enabled;
509 define a command string that is automatically executed
510 when no character is read on the console interface
511 within "Boot Delay" after reset.
514 This can be used to pass arguments to the bootm
515 command. The value of CONFIG_BOOTARGS goes into the
516 environment value "bootargs".
518 CONFIG_RAMBOOT and CONFIG_NFSBOOT
519 The value of these goes into the environment as
520 "ramboot" and "nfsboot" respectively, and can be used
521 as a convenience, when switching between booting from
527 When this option is #defined, the existence of the
528 environment variable "preboot" will be checked
529 immediately before starting the CONFIG_BOOTDELAY
530 countdown and/or running the auto-boot command resp.
531 entering interactive mode.
533 This feature is especially useful when "preboot" is
534 automatically generated or modified. For an example
535 see the LWMON board specific code: here "preboot" is
536 modified when the user holds down a certain
537 combination of keys on the (special) keyboard when
540 - Serial Download Echo Mode:
542 If defined to 1, all characters received during a
543 serial download (using the "loads" command) are
544 echoed back. This might be needed by some terminal
545 emulations (like "cu"), but may as well just take
546 time on others. This setting #define's the initial
547 value of the "loads_echo" environment variable.
549 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
551 Select one of the baudrates listed in
552 CFG_BAUDRATE_TABLE, see below.
555 Monitor commands can be included or excluded
556 from the build by using the #include files
557 "config_cmd_all.h" and #undef'ing unwanted
558 commands, or using "config_cmd_default.h"
559 and augmenting with additional #define's
562 The default command configuration includes all commands
563 except those marked below with a "*".
565 CONFIG_CMD_ASKENV * ask for env variable
566 CONFIG_CMD_AUTOSCRIPT Autoscript Support
567 CONFIG_CMD_BDI bdinfo
568 CONFIG_CMD_BEDBUG * Include BedBug Debugger
569 CONFIG_CMD_BMP * BMP support
570 CONFIG_CMD_BSP * Board specific commands
571 CONFIG_CMD_BOOTD bootd
572 CONFIG_CMD_CACHE * icache, dcache
573 CONFIG_CMD_CONSOLE coninfo
574 CONFIG_CMD_DATE * support for RTC, date/time...
575 CONFIG_CMD_DHCP * DHCP support
576 CONFIG_CMD_DIAG * Diagnostics
577 CONFIG_CMD_DOC * Disk-On-Chip Support
578 CONFIG_CMD_DTT * Digital Therm and Thermostat
579 CONFIG_CMD_ECHO echo arguments
580 CONFIG_CMD_EEPROM * EEPROM read/write support
581 CONFIG_CMD_ELF * bootelf, bootvx
582 CONFIG_CMD_ENV saveenv
583 CONFIG_CMD_FDC * Floppy Disk Support
584 CONFIG_CMD_FAT * FAT partition support
585 CONFIG_CMD_FDOS * Dos diskette Support
586 CONFIG_CMD_FLASH flinfo, erase, protect
587 CONFIG_CMD_FPGA FPGA device initialization support
588 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
589 CONFIG_CMD_I2C * I2C serial bus support
590 CONFIG_CMD_IDE * IDE harddisk support
591 CONFIG_CMD_IMI iminfo
592 CONFIG_CMD_IMLS List all found images
593 CONFIG_CMD_IMMAP * IMMR dump support
594 CONFIG_CMD_IRQ * irqinfo
595 CONFIG_CMD_ITEST Integer/string test of 2 values
596 CONFIG_CMD_JFFS2 * JFFS2 Support
597 CONFIG_CMD_KGDB * kgdb
598 CONFIG_CMD_LOADB loadb
599 CONFIG_CMD_LOADS loads
600 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
602 CONFIG_CMD_MISC Misc functions like sleep etc
603 CONFIG_CMD_MMC * MMC memory mapped support
604 CONFIG_CMD_MII * MII utility commands
605 CONFIG_CMD_NAND * NAND support
606 CONFIG_CMD_NET bootp, tftpboot, rarpboot
607 CONFIG_CMD_PCI * pciinfo
608 CONFIG_CMD_PCMCIA * PCMCIA support
609 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
611 CONFIG_CMD_PORTIO * Port I/O
612 CONFIG_CMD_REGINFO * Register dump
613 CONFIG_CMD_RUN run command in env variable
614 CONFIG_CMD_SAVES * save S record dump
615 CONFIG_CMD_SCSI * SCSI Support
616 CONFIG_CMD_SDRAM * print SDRAM configuration information
617 (requires CONFIG_CMD_I2C)
618 CONFIG_CMD_SETGETDCR Support for DCR Register access
620 CONFIG_CMD_SPI * SPI serial bus support
621 CONFIG_CMD_USB * USB support
622 CONFIG_CMD_VFD * VFD support (TRAB)
623 CONFIG_CMD_BSP * Board SPecific functions
624 CONFIG_CMD_CDP * Cisco Discover Protocol support
625 CONFIG_CMD_FSL * Microblaze FSL support
628 EXAMPLE: If you want all functions except of network
629 support you can write:
631 #include "config_cmd_all.h"
632 #undef CONFIG_CMD_NET
635 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
637 Note: Don't enable the "icache" and "dcache" commands
638 (configuration option CONFIG_CMD_CACHE) unless you know
639 what you (and your U-Boot users) are doing. Data
640 cache cannot be enabled on systems like the 8xx or
641 8260 (where accesses to the IMMR region must be
642 uncached), and it cannot be disabled on all other
643 systems where we (mis-) use the data cache to hold an
644 initial stack and some data.
647 XXX - this list needs to get updated!
651 If this variable is defined, it enables watchdog
652 support. There must be support in the platform specific
653 code for a watchdog. For the 8xx and 8260 CPUs, the
654 SIU Watchdog feature is enabled in the SYPCR
658 CONFIG_VERSION_VARIABLE
659 If this variable is defined, an environment variable
660 named "ver" is created by U-Boot showing the U-Boot
661 version as printed by the "version" command.
662 This variable is readonly.
666 When CONFIG_CMD_DATE is selected, the type of the RTC
667 has to be selected, too. Define exactly one of the
670 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
671 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
672 CONFIG_RTC_MC146818 - use MC146818 RTC
673 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
674 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
675 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
676 CONFIG_RTC_DS164x - use Dallas DS164x RTC
677 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
678 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
679 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
681 Note that if the RTC uses I2C, then the I2C interface
682 must also be configured. See I2C Support, below.
686 When CONFIG_TIMESTAMP is selected, the timestamp
687 (date and time) of an image is printed by image
688 commands like bootm or iminfo. This option is
689 automatically enabled when you select CONFIG_CMD_DATE .
692 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
693 and/or CONFIG_ISO_PARTITION
695 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
696 CONFIG_CMD_SCSI) you must configure support for at
697 least one partition type as well.
700 CONFIG_IDE_RESET_ROUTINE - this is defined in several
701 board configurations files but used nowhere!
703 CONFIG_IDE_RESET - is this is defined, IDE Reset will
704 be performed by calling the function
705 ide_set_reset(int reset)
706 which has to be defined in a board specific file
711 Set this to enable ATAPI support.
716 Set this to enable support for disks larger than 137GB
717 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
718 Whithout these , LBA48 support uses 32bit variables and will 'only'
719 support disks up to 2.1TB.
722 When enabled, makes the IDE subsystem use 64bit sector addresses.
726 At the moment only there is only support for the
727 SYM53C8XX SCSI controller; define
728 CONFIG_SCSI_SYM53C8XX to enable it.
730 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
731 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
732 CFG_SCSI_MAX_LUN] can be adjusted to define the
733 maximum numbers of LUNs, SCSI ID's and target
735 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
737 - NETWORK Support (PCI):
739 Support for Intel 8254x gigabit chips.
742 Support for Intel 82557/82559/82559ER chips.
743 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
744 write routine for first time initialisation.
747 Support for Digital 2114x chips.
748 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
749 modem chip initialisation (KS8761/QS6611).
752 Support for National dp83815 chips.
755 Support for National dp8382[01] gigabit chips.
757 - NETWORK Support (other):
759 CONFIG_DRIVER_LAN91C96
760 Support for SMSC's LAN91C96 chips.
763 Define this to hold the physical address
764 of the LAN91C96's I/O space
766 CONFIG_LAN91C96_USE_32_BIT
767 Define this to enable 32 bit addressing
769 CONFIG_DRIVER_SMC91111
770 Support for SMSC's LAN91C111 chip
773 Define this to hold the physical address
774 of the device (I/O space)
776 CONFIG_SMC_USE_32_BIT
777 Define this if data bus is 32 bits
779 CONFIG_SMC_USE_IOFUNCS
780 Define this to use i/o functions instead of macros
781 (some hardware wont work with macros)
784 At the moment only the UHCI host controller is
785 supported (PIP405, MIP405, MPC5200); define
786 CONFIG_USB_UHCI to enable it.
787 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
788 and define CONFIG_USB_STORAGE to enable the USB
791 Supported are USB Keyboards and USB Floppy drives
793 MPC5200 USB requires additional defines:
795 for 528 MHz Clock: 0x0001bbbb
797 for differential drivers: 0x00001000
798 for single ended drivers: 0x00005000
800 May be defined to allow interrupt polling
801 instead of using asynchronous interrupts
804 Define the below if you wish to use the USB console.
805 Once firmware is rebuilt from a serial console issue the
806 command "setenv stdin usbtty; setenv stdout usbtty" and
807 attach your usb cable. The Unix command "dmesg" should print
808 it has found a new device. The environment variable usbtty
809 can be set to gserial or cdc_acm to enable your device to
810 appear to a USB host as a Linux gserial device or a
811 Common Device Class Abstract Control Model serial device.
812 If you select usbtty = gserial you should be able to enumerate
814 # modprobe usbserial vendor=0xVendorID product=0xProductID
815 else if using cdc_acm, simply setting the environment
816 variable usbtty to be cdc_acm should suffice. The following
817 might be defined in YourBoardName.h
820 Define this to build a UDC device
823 Define this to have a tty type of device available to
824 talk to the UDC device
826 CFG_CONSOLE_IS_IN_ENV
827 Define this if you want stdin, stdout &/or stderr to
831 CFG_USB_EXTC_CLK 0xBLAH
832 Derive USB clock from external clock "blah"
833 - CFG_USB_EXTC_CLK 0x02
835 CFG_USB_BRG_CLK 0xBLAH
836 Derive USB clock from brgclk
837 - CFG_USB_BRG_CLK 0x04
839 If you have a USB-IF assigned VendorID then you may wish to
840 define your own vendor specific values either in BoardName.h
841 or directly in usbd_vendor_info.h. If you don't define
842 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
843 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
844 should pretend to be a Linux device to it's target host.
846 CONFIG_USBD_MANUFACTURER
847 Define this string as the name of your company for
848 - CONFIG_USBD_MANUFACTURER "my company"
850 CONFIG_USBD_PRODUCT_NAME
851 Define this string as the name of your product
852 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
855 Define this as your assigned Vendor ID from the USB
856 Implementors Forum. This *must* be a genuine Vendor ID
857 to avoid polluting the USB namespace.
858 - CONFIG_USBD_VENDORID 0xFFFF
860 CONFIG_USBD_PRODUCTID
861 Define this as the unique Product ID
863 - CONFIG_USBD_PRODUCTID 0xFFFF
867 The MMC controller on the Intel PXA is supported. To
868 enable this define CONFIG_MMC. The MMC can be
869 accessed from the boot prompt by mapping the device
870 to physical memory similar to flash. Command line is
871 enabled with CONFIG_CMD_MMC. The MMC driver also works with
872 the FAT fs. This is enabled with CONFIG_CMD_FAT.
874 - Journaling Flash filesystem support:
875 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
876 CONFIG_JFFS2_NAND_DEV
877 Define these for a default partition on a NAND device
879 CFG_JFFS2_FIRST_SECTOR,
880 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
881 Define these for a default partition on a NOR device
884 Define this to create an own partition. You have to provide a
885 function struct part_info* jffs2_part_info(int part_num)
887 If you define only one JFFS2 partition you may also want to
888 #define CFG_JFFS_SINGLE_PART 1
889 to disable the command chpart. This is the default when you
890 have not defined a custom partition
895 Define this to enable standard (PC-Style) keyboard
899 Standard PC keyboard driver with US (is default) and
900 GERMAN key layout (switch via environment 'keymap=de') support.
901 Export function i8042_kbd_init, i8042_tstc and i8042_getc
902 for cfb_console. Supports cursor blinking.
907 Define this to enable video support (for output to
912 Enable Chips & Technologies 69000 Video chip
914 CONFIG_VIDEO_SMI_LYNXEM
915 Enable Silicon Motion SMI 712/710/810 Video chip. The
916 video output is selected via environment 'videoout'
917 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
920 For the CT69000 and SMI_LYNXEM drivers, videomode is
921 selected via environment 'videomode'. Two diferent ways
923 - "videomode=num" 'num' is a standard LiLo mode numbers.
924 Following standard modes are supported (* is default):
926 Colors 640x480 800x600 1024x768 1152x864 1280x1024
927 -------------+---------------------------------------------
928 8 bits | 0x301* 0x303 0x305 0x161 0x307
929 15 bits | 0x310 0x313 0x316 0x162 0x319
930 16 bits | 0x311 0x314 0x317 0x163 0x31A
931 24 bits | 0x312 0x315 0x318 ? 0x31B
932 -------------+---------------------------------------------
933 (i.e. setenv videomode 317; saveenv; reset;)
935 - "videomode=bootargs" all the video parameters are parsed
936 from the bootargs. (See drivers/video/videomodes.c)
939 CONFIG_VIDEO_SED13806
940 Enable Epson SED13806 driver. This driver supports 8bpp
941 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
942 or CONFIG_VIDEO_SED13806_16BPP
947 Define this to enable a custom keyboard support.
948 This simply calls drv_keyboard_init() which must be
949 defined in your board-specific files.
950 The only board using this so far is RBC823.
952 - LCD Support: CONFIG_LCD
954 Define this to enable LCD support (for output to LCD
955 display); also select one of the supported displays
956 by defining one of these:
958 CONFIG_NEC_NL6448AC33:
960 NEC NL6448AC33-18. Active, color, single scan.
962 CONFIG_NEC_NL6448BC20
964 NEC NL6448BC20-08. 6.5", 640x480.
965 Active, color, single scan.
967 CONFIG_NEC_NL6448BC33_54
969 NEC NL6448BC33-54. 10.4", 640x480.
970 Active, color, single scan.
974 Sharp 320x240. Active, color, single scan.
975 It isn't 16x9, and I am not sure what it is.
977 CONFIG_SHARP_LQ64D341
979 Sharp LQ64D341 display, 640x480.
980 Active, color, single scan.
984 HLD1045 display, 640x480.
985 Active, color, single scan.
989 Optrex CBL50840-2 NF-FW 99 22 M5
991 Hitachi LMG6912RPFC-00T
995 320x240. Black & white.
997 Normally display is black on white background; define
998 CFG_WHITE_ON_BLACK to get it inverted.
1000 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1002 If this option is set, the environment is checked for
1003 a variable "splashimage". If found, the usual display
1004 of logo, copyright and system information on the LCD
1005 is suppressed and the BMP image at the address
1006 specified in "splashimage" is loaded instead. The
1007 console is redirected to the "nulldev", too. This
1008 allows for a "silent" boot where a splash screen is
1009 loaded very quickly after power-on.
1011 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1013 If this option is set, additionally to standard BMP
1014 images, gzipped BMP images can be displayed via the
1015 splashscreen support or the bmp command.
1017 - Compression support:
1020 If this option is set, support for bzip2 compressed
1021 images is included. If not, only uncompressed and gzip
1022 compressed images are supported.
1024 NOTE: the bzip2 algorithm requires a lot of RAM, so
1025 the malloc area (as defined by CFG_MALLOC_LEN) should
1031 The address of PHY on MII bus.
1033 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1035 The clock frequency of the MII bus
1039 If this option is set, support for speed/duplex
1040 detection of Gigabit PHY is included.
1042 CONFIG_PHY_RESET_DELAY
1044 Some PHY like Intel LXT971A need extra delay after
1045 reset before any MII register access is possible.
1046 For such PHY, set this option to the usec delay
1047 required. (minimum 300usec for LXT971A)
1049 CONFIG_PHY_CMD_DELAY (ppc4xx)
1051 Some PHY like Intel LXT971A need extra delay after
1052 command issued before MII status register can be read
1059 Define a default value for ethernet address to use
1060 for the respective ethernet interface, in case this
1061 is not determined automatically.
1066 Define a default value for the IP address to use for
1067 the default ethernet interface, in case this is not
1068 determined through e.g. bootp.
1070 - Server IP address:
1073 Defines a default value for theIP address of a TFTP
1074 server to contact when using the "tftboot" command.
1076 - Multicast TFTP Mode:
1079 Defines whether you want to support multicast TFTP as per
1080 rfc-2090; for example to work with atftp. Lets lots of targets
1081 tftp down the same boot image concurrently. Note: the ethernet
1082 driver in use must provide a function: mcast() to join/leave a
1085 CONFIG_BOOTP_RANDOM_DELAY
1086 - BOOTP Recovery Mode:
1087 CONFIG_BOOTP_RANDOM_DELAY
1089 If you have many targets in a network that try to
1090 boot using BOOTP, you may want to avoid that all
1091 systems send out BOOTP requests at precisely the same
1092 moment (which would happen for instance at recovery
1093 from a power failure, when all systems will try to
1094 boot, thus flooding the BOOTP server. Defining
1095 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1096 inserted before sending out BOOTP requests. The
1097 following delays are inserted then:
1099 1st BOOTP request: delay 0 ... 1 sec
1100 2nd BOOTP request: delay 0 ... 2 sec
1101 3rd BOOTP request: delay 0 ... 4 sec
1103 BOOTP requests: delay 0 ... 8 sec
1105 - DHCP Advanced Options:
1106 You can fine tune the DHCP functionality by defining
1107 CONFIG_BOOTP_* symbols:
1109 CONFIG_BOOTP_SUBNETMASK
1110 CONFIG_BOOTP_GATEWAY
1111 CONFIG_BOOTP_HOSTNAME
1112 CONFIG_BOOTP_NISDOMAIN
1113 CONFIG_BOOTP_BOOTPATH
1114 CONFIG_BOOTP_BOOTFILESIZE
1117 CONFIG_BOOTP_SEND_HOSTNAME
1118 CONFIG_BOOTP_NTPSERVER
1119 CONFIG_BOOTP_TIMEOFFSET
1120 CONFIG_BOOTP_VENDOREX
1122 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1123 environment variable, not the BOOTP server.
1125 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1126 serverip from a DHCP server, it is possible that more
1127 than one DNS serverip is offered to the client.
1128 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1129 serverip will be stored in the additional environment
1130 variable "dnsip2". The first DNS serverip is always
1131 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1134 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1135 to do a dynamic update of a DNS server. To do this, they
1136 need the hostname of the DHCP requester.
1137 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1138 of the "hostname" environment variable is passed as
1139 option 12 to the DHCP server.
1142 CONFIG_CDP_DEVICE_ID
1144 The device id used in CDP trigger frames.
1146 CONFIG_CDP_DEVICE_ID_PREFIX
1148 A two character string which is prefixed to the MAC address
1153 A printf format string which contains the ascii name of
1154 the port. Normally is set to "eth%d" which sets
1155 eth0 for the first ethernet, eth1 for the second etc.
1157 CONFIG_CDP_CAPABILITIES
1159 A 32bit integer which indicates the device capabilities;
1160 0x00000010 for a normal host which does not forwards.
1164 An ascii string containing the version of the software.
1168 An ascii string containing the name of the platform.
1172 A 32bit integer sent on the trigger.
1174 CONFIG_CDP_POWER_CONSUMPTION
1176 A 16bit integer containing the power consumption of the
1177 device in .1 of milliwatts.
1179 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1181 A byte containing the id of the VLAN.
1183 - Status LED: CONFIG_STATUS_LED
1185 Several configurations allow to display the current
1186 status using a LED. For instance, the LED will blink
1187 fast while running U-Boot code, stop blinking as
1188 soon as a reply to a BOOTP request was received, and
1189 start blinking slow once the Linux kernel is running
1190 (supported by a status LED driver in the Linux
1191 kernel). Defining CONFIG_STATUS_LED enables this
1194 - CAN Support: CONFIG_CAN_DRIVER
1196 Defining CONFIG_CAN_DRIVER enables CAN driver support
1197 on those systems that support this (optional)
1198 feature, like the TQM8xxL modules.
1200 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1202 These enable I2C serial bus commands. Defining either of
1203 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1204 include the appropriate I2C driver for the selected cpu.
1206 This will allow you to use i2c commands at the u-boot
1207 command line (as long as you set CONFIG_CMD_I2C in
1208 CONFIG_COMMANDS) and communicate with i2c based realtime
1209 clock chips. See common/cmd_i2c.c for a description of the
1210 command line interface.
1212 CONFIG_I2C_CMD_TREE is a recommended option that places
1213 all I2C commands under a single 'i2c' root command. The
1214 older 'imm', 'imd', 'iprobe' etc. commands are considered
1215 deprecated and may disappear in the future.
1217 CONFIG_HARD_I2C selects a hardware I2C controller.
1219 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1220 bit-banging) driver instead of CPM or similar hardware
1223 There are several other quantities that must also be
1224 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1226 In both cases you will need to define CFG_I2C_SPEED
1227 to be the frequency (in Hz) at which you wish your i2c bus
1228 to run and CFG_I2C_SLAVE to be the address of this node (ie
1229 the cpu's i2c node address).
1231 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1232 sets the cpu up as a master node and so its address should
1233 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1234 p.16-473). So, set CFG_I2C_SLAVE to 0.
1236 That's all that's required for CONFIG_HARD_I2C.
1238 If you use the software i2c interface (CONFIG_SOFT_I2C)
1239 then the following macros need to be defined (examples are
1240 from include/configs/lwmon.h):
1244 (Optional). Any commands necessary to enable the I2C
1245 controller or configure ports.
1247 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1251 (Only for MPC8260 CPU). The I/O port to use (the code
1252 assumes both bits are on the same port). Valid values
1253 are 0..3 for ports A..D.
1257 The code necessary to make the I2C data line active
1258 (driven). If the data line is open collector, this
1261 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1265 The code necessary to make the I2C data line tri-stated
1266 (inactive). If the data line is open collector, this
1269 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1273 Code that returns TRUE if the I2C data line is high,
1276 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1280 If <bit> is TRUE, sets the I2C data line high. If it
1281 is FALSE, it clears it (low).
1283 eg: #define I2C_SDA(bit) \
1284 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1285 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1289 If <bit> is TRUE, sets the I2C clock line high. If it
1290 is FALSE, it clears it (low).
1292 eg: #define I2C_SCL(bit) \
1293 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1294 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1298 This delay is invoked four times per clock cycle so this
1299 controls the rate of data transfer. The data rate thus
1300 is 1 / (I2C_DELAY * 4). Often defined to be something
1303 #define I2C_DELAY udelay(2)
1307 When a board is reset during an i2c bus transfer
1308 chips might think that the current transfer is still
1309 in progress. On some boards it is possible to access
1310 the i2c SCLK line directly, either by using the
1311 processor pin as a GPIO or by having a second pin
1312 connected to the bus. If this option is defined a
1313 custom i2c_init_board() routine in boards/xxx/board.c
1314 is run early in the boot sequence.
1316 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1318 This option enables configuration of bi_iic_fast[] flags
1319 in u-boot bd_info structure based on u-boot environment
1320 variable "i2cfast". (see also i2cfast)
1322 CONFIG_I2C_MULTI_BUS
1324 This option allows the use of multiple I2C buses, each of which
1325 must have a controller. At any point in time, only one bus is
1326 active. To switch to a different bus, use the 'i2c dev' command.
1327 Note that bus numbering is zero-based.
1331 This option specifies a list of I2C devices that will be skipped
1332 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1333 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1334 pairs. Otherwise, specify a 1D array of device addresses
1337 #undef CONFIG_I2C_MULTI_BUS
1338 #define CFG_I2C_NOPROBES {0x50,0x68}
1340 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1342 #define CONFIG_I2C_MULTI_BUS
1343 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1345 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1349 If defined, then this indicates the I2C bus number for DDR SPD.
1350 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1354 If defined, then this indicates the I2C bus number for the RTC.
1355 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1359 If defined, then this indicates the I2C bus number for the DTT.
1360 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1364 Define this option if you want to use Freescale's I2C driver in
1365 drivers/i2c/fsl_i2c.c.
1368 - SPI Support: CONFIG_SPI
1370 Enables SPI driver (so far only tested with
1371 SPI EEPROM, also an instance works with Crystal A/D and
1372 D/As on the SACSng board)
1376 Enables extended (16-bit) SPI EEPROM addressing.
1377 (symmetrical to CONFIG_I2C_X)
1381 Enables a software (bit-bang) SPI driver rather than
1382 using hardware support. This is a general purpose
1383 driver that only requires three general I/O port pins
1384 (two outputs, one input) to function. If this is
1385 defined, the board configuration must define several
1386 SPI configuration items (port pins to use, etc). For
1387 an example, see include/configs/sacsng.h.
1391 Enables a hardware SPI driver for general-purpose reads
1392 and writes. As with CONFIG_SOFT_SPI, the board configuration
1393 must define a list of chip-select function pointers.
1394 Currently supported on some MPC8xxx processors. For an
1395 example, see include/configs/mpc8349emds.h.
1397 - FPGA Support: CONFIG_FPGA
1399 Enables FPGA subsystem.
1401 CONFIG_FPGA_<vendor>
1403 Enables support for specific chip vendors.
1406 CONFIG_FPGA_<family>
1408 Enables support for FPGA family.
1409 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1413 Specify the number of FPGA devices to support.
1415 CFG_FPGA_PROG_FEEDBACK
1417 Enable printing of hash marks during FPGA configuration.
1421 Enable checks on FPGA configuration interface busy
1422 status by the configuration function. This option
1423 will require a board or device specific function to
1428 If defined, a function that provides delays in the FPGA
1429 configuration driver.
1431 CFG_FPGA_CHECK_CTRLC
1432 Allow Control-C to interrupt FPGA configuration
1434 CFG_FPGA_CHECK_ERROR
1436 Check for configuration errors during FPGA bitfile
1437 loading. For example, abort during Virtex II
1438 configuration if the INIT_B line goes low (which
1439 indicated a CRC error).
1443 Maximum time to wait for the INIT_B line to deassert
1444 after PROB_B has been deasserted during a Virtex II
1445 FPGA configuration sequence. The default time is 500
1450 Maximum time to wait for BUSY to deassert during
1451 Virtex II FPGA configuration. The default is 5 mS.
1453 CFG_FPGA_WAIT_CONFIG
1455 Time to wait after FPGA configuration. The default is
1458 - Configuration Management:
1461 If defined, this string will be added to the U-Boot
1462 version information (U_BOOT_VERSION)
1464 - Vendor Parameter Protection:
1466 U-Boot considers the values of the environment
1467 variables "serial#" (Board Serial Number) and
1468 "ethaddr" (Ethernet Address) to be parameters that
1469 are set once by the board vendor / manufacturer, and
1470 protects these variables from casual modification by
1471 the user. Once set, these variables are read-only,
1472 and write or delete attempts are rejected. You can
1473 change this behviour:
1475 If CONFIG_ENV_OVERWRITE is #defined in your config
1476 file, the write protection for vendor parameters is
1477 completely disabled. Anybody can change or delete
1480 Alternatively, if you #define _both_ CONFIG_ETHADDR
1481 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1482 ethernet address is installed in the environment,
1483 which can be changed exactly ONCE by the user. [The
1484 serial# is unaffected by this, i. e. it remains
1490 Define this variable to enable the reservation of
1491 "protected RAM", i. e. RAM which is not overwritten
1492 by U-Boot. Define CONFIG_PRAM to hold the number of
1493 kB you want to reserve for pRAM. You can overwrite
1494 this default value by defining an environment
1495 variable "pram" to the number of kB you want to
1496 reserve. Note that the board info structure will
1497 still show the full amount of RAM. If pRAM is
1498 reserved, a new environment variable "mem" will
1499 automatically be defined to hold the amount of
1500 remaining RAM in a form that can be passed as boot
1501 argument to Linux, for instance like that:
1503 setenv bootargs ... mem=\${mem}
1506 This way you can tell Linux not to use this memory,
1507 either, which results in a memory region that will
1508 not be affected by reboots.
1510 *WARNING* If your board configuration uses automatic
1511 detection of the RAM size, you must make sure that
1512 this memory test is non-destructive. So far, the
1513 following board configurations are known to be
1516 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1517 HERMES, IP860, RPXlite, LWMON, LANTEC,
1518 PCU_E, FLAGADM, TQM8260
1523 Define this variable to stop the system in case of a
1524 fatal error, so that you have to reset it manually.
1525 This is probably NOT a good idea for an embedded
1526 system where you want to system to reboot
1527 automatically as fast as possible, but it may be
1528 useful during development since you can try to debug
1529 the conditions that lead to the situation.
1531 CONFIG_NET_RETRY_COUNT
1533 This variable defines the number of retries for
1534 network operations like ARP, RARP, TFTP, or BOOTP
1535 before giving up the operation. If not defined, a
1536 default value of 5 is used.
1538 - Command Interpreter:
1539 CONFIG_AUTO_COMPLETE
1541 Enable auto completion of commands using TAB.
1543 Note that this feature has NOT been implemented yet
1544 for the "hush" shell.
1549 Define this variable to enable the "hush" shell (from
1550 Busybox) as command line interpreter, thus enabling
1551 powerful command line syntax like
1552 if...then...else...fi conditionals or `&&' and '||'
1553 constructs ("shell scripts").
1555 If undefined, you get the old, much simpler behaviour
1556 with a somewhat smaller memory footprint.
1561 This defines the secondary prompt string, which is
1562 printed when the command interpreter needs more input
1563 to complete a command. Usually "> ".
1567 In the current implementation, the local variables
1568 space and global environment variables space are
1569 separated. Local variables are those you define by
1570 simply typing `name=value'. To access a local
1571 variable later on, you have write `$name' or
1572 `${name}'; to execute the contents of a variable
1573 directly type `$name' at the command prompt.
1575 Global environment variables are those you use
1576 setenv/printenv to work with. To run a command stored
1577 in such a variable, you need to use the run command,
1578 and you must not use the '$' sign to access them.
1580 To store commands and special characters in a
1581 variable, please use double quotation marks
1582 surrounding the whole text of the variable, instead
1583 of the backslashes before semicolons and special
1586 - Commandline Editing and History:
1587 CONFIG_CMDLINE_EDITING
1589 Enable editiong and History functions for interactive
1590 commandline input operations
1592 - Default Environment:
1593 CONFIG_EXTRA_ENV_SETTINGS
1595 Define this to contain any number of null terminated
1596 strings (variable = value pairs) that will be part of
1597 the default environment compiled into the boot image.
1599 For example, place something like this in your
1600 board's config file:
1602 #define CONFIG_EXTRA_ENV_SETTINGS \
1606 Warning: This method is based on knowledge about the
1607 internal format how the environment is stored by the
1608 U-Boot code. This is NOT an official, exported
1609 interface! Although it is unlikely that this format
1610 will change soon, there is no guarantee either.
1611 You better know what you are doing here.
1613 Note: overly (ab)use of the default environment is
1614 discouraged. Make sure to check other ways to preset
1615 the environment like the autoscript function or the
1618 - DataFlash Support:
1619 CONFIG_HAS_DATAFLASH
1621 Defining this option enables DataFlash features and
1622 allows to read/write in Dataflash via the standard
1625 - SystemACE Support:
1628 Adding this option adds support for Xilinx SystemACE
1629 chips attached via some sort of local bus. The address
1630 of the chip must alsh be defined in the
1631 CFG_SYSTEMACE_BASE macro. For example:
1633 #define CONFIG_SYSTEMACE
1634 #define CFG_SYSTEMACE_BASE 0xf0000000
1636 When SystemACE support is added, the "ace" device type
1637 becomes available to the fat commands, i.e. fatls.
1639 - TFTP Fixed UDP Port:
1642 If this is defined, the environment variable tftpsrcp
1643 is used to supply the TFTP UDP source port value.
1644 If tftpsrcp isn't defined, the normal pseudo-random port
1645 number generator is used.
1647 Also, the environment variable tftpdstp is used to supply
1648 the TFTP UDP destination port value. If tftpdstp isn't
1649 defined, the normal port 69 is used.
1651 The purpose for tftpsrcp is to allow a TFTP server to
1652 blindly start the TFTP transfer using the pre-configured
1653 target IP address and UDP port. This has the effect of
1654 "punching through" the (Windows XP) firewall, allowing
1655 the remainder of the TFTP transfer to proceed normally.
1656 A better solution is to properly configure the firewall,
1657 but sometimes that is not allowed.
1659 - Show boot progress:
1660 CONFIG_SHOW_BOOT_PROGRESS
1662 Defining this option allows to add some board-
1663 specific code (calling a user-provided function
1664 "show_boot_progress(int)") that enables you to show
1665 the system's boot progress on some display (for
1666 example, some LED's) on your board. At the moment,
1667 the following checkpoints are implemented:
1669 Legacy uImage format:
1672 1 common/cmd_bootm.c before attempting to boot an image
1673 -1 common/cmd_bootm.c Image header has bad magic number
1674 2 common/cmd_bootm.c Image header has correct magic number
1675 -2 common/cmd_bootm.c Image header has bad checksum
1676 3 common/cmd_bootm.c Image header has correct checksum
1677 -3 common/cmd_bootm.c Image data has bad checksum
1678 4 common/cmd_bootm.c Image data has correct checksum
1679 -4 common/cmd_bootm.c Image is for unsupported architecture
1680 5 common/cmd_bootm.c Architecture check OK
1681 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1682 6 common/cmd_bootm.c Image Type check OK
1683 -6 common/cmd_bootm.c gunzip uncompression error
1684 -7 common/cmd_bootm.c Unimplemented compression type
1685 7 common/cmd_bootm.c Uncompression OK
1686 8 common/cmd_bootm.c No uncompress/copy overwrite error
1687 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1689 9 common/image.c Start initial ramdisk verification
1690 -10 common/image.c Ramdisk header has bad magic number
1691 -11 common/image.c Ramdisk header has bad checksum
1692 10 common/image.c Ramdisk header is OK
1693 -12 common/image.c Ramdisk data has bad checksum
1694 11 common/image.c Ramdisk data has correct checksum
1695 12 common/image.c Ramdisk verification complete, start loading
1696 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1697 13 common/image.c Start multifile image verification
1698 14 common/image.c No initial ramdisk, no multifile, continue.
1700 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1702 -30 lib_ppc/board.c Fatal error, hang the system
1703 -31 post/post.c POST test failed, detected by post_output_backlog()
1704 -32 post/post.c POST test failed, detected by post_run_single()
1706 34 common/cmd_doc.c before loading a Image from a DOC device
1707 -35 common/cmd_doc.c Bad usage of "doc" command
1708 35 common/cmd_doc.c correct usage of "doc" command
1709 -36 common/cmd_doc.c No boot device
1710 36 common/cmd_doc.c correct boot device
1711 -37 common/cmd_doc.c Unknown Chip ID on boot device
1712 37 common/cmd_doc.c correct chip ID found, device available
1713 -38 common/cmd_doc.c Read Error on boot device
1714 38 common/cmd_doc.c reading Image header from DOC device OK
1715 -39 common/cmd_doc.c Image header has bad magic number
1716 39 common/cmd_doc.c Image header has correct magic number
1717 -40 common/cmd_doc.c Error reading Image from DOC device
1718 40 common/cmd_doc.c Image header has correct magic number
1719 41 common/cmd_ide.c before loading a Image from a IDE device
1720 -42 common/cmd_ide.c Bad usage of "ide" command
1721 42 common/cmd_ide.c correct usage of "ide" command
1722 -43 common/cmd_ide.c No boot device
1723 43 common/cmd_ide.c boot device found
1724 -44 common/cmd_ide.c Device not available
1725 44 common/cmd_ide.c Device available
1726 -45 common/cmd_ide.c wrong partition selected
1727 45 common/cmd_ide.c partition selected
1728 -46 common/cmd_ide.c Unknown partition table
1729 46 common/cmd_ide.c valid partition table found
1730 -47 common/cmd_ide.c Invalid partition type
1731 47 common/cmd_ide.c correct partition type
1732 -48 common/cmd_ide.c Error reading Image Header on boot device
1733 48 common/cmd_ide.c reading Image Header from IDE device OK
1734 -49 common/cmd_ide.c Image header has bad magic number
1735 49 common/cmd_ide.c Image header has correct magic number
1736 -50 common/cmd_ide.c Image header has bad checksum
1737 50 common/cmd_ide.c Image header has correct checksum
1738 -51 common/cmd_ide.c Error reading Image from IDE device
1739 51 common/cmd_ide.c reading Image from IDE device OK
1740 52 common/cmd_nand.c before loading a Image from a NAND device
1741 -53 common/cmd_nand.c Bad usage of "nand" command
1742 53 common/cmd_nand.c correct usage of "nand" command
1743 -54 common/cmd_nand.c No boot device
1744 54 common/cmd_nand.c boot device found
1745 -55 common/cmd_nand.c Unknown Chip ID on boot device
1746 55 common/cmd_nand.c correct chip ID found, device available
1747 -56 common/cmd_nand.c Error reading Image Header on boot device
1748 56 common/cmd_nand.c reading Image Header from NAND device OK
1749 -57 common/cmd_nand.c Image header has bad magic number
1750 57 common/cmd_nand.c Image header has correct magic number
1751 -58 common/cmd_nand.c Error reading Image from NAND device
1752 58 common/cmd_nand.c reading Image from NAND device OK
1754 -60 common/env_common.c Environment has a bad CRC, using default
1756 64 net/eth.c starting with Ethernetconfiguration.
1757 -64 net/eth.c no Ethernet found.
1758 65 net/eth.c Ethernet found.
1760 -80 common/cmd_net.c usage wrong
1761 80 common/cmd_net.c before calling NetLoop()
1762 -81 common/cmd_net.c some error in NetLoop() occured
1763 81 common/cmd_net.c NetLoop() back without error
1764 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1765 82 common/cmd_net.c trying automatic boot
1766 83 common/cmd_net.c running autoscript
1767 -83 common/cmd_net.c some error in automatic boot or autoscript
1768 84 common/cmd_net.c end without errors
1773 100 common/cmd_bootm.c Kernel FIT Image has correct format
1774 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1775 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1776 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1777 102 common/cmd_bootm.c Kernel unit name specified
1778 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1779 103 common/cmd_bootm.c Found configuration node
1780 104 common/cmd_bootm.c Got kernel subimage node offset
1781 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1782 105 common/cmd_bootm.c Kernel subimage hash verification OK
1783 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1784 106 common/cmd_bootm.c Architecture check OK
1785 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1786 107 common/cmd_bootm.c Kernel subimge type OK
1787 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1788 108 common/cmd_bootm.c Got kernel subimage data/size
1789 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1790 -109 common/cmd_bootm.c Can't get kernel subimage type
1791 -110 common/cmd_bootm.c Can't get kernel subimage comp
1792 -111 common/cmd_bootm.c Can't get kernel subimage os
1793 -112 common/cmd_bootm.c Can't get kernel subimage load address
1794 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1796 120 common/image.c Start initial ramdisk verification
1797 -120 common/image.c Ramdisk FIT image has incorrect format
1798 121 common/image.c Ramdisk FIT image has correct format
1799 122 common/image.c No Ramdisk subimage unit name, using configuration
1800 -122 common/image.c Can't get configuration for ramdisk subimage
1801 123 common/image.c Ramdisk unit name specified
1802 -124 common/image.c Can't get ramdisk subimage node offset
1803 125 common/image.c Got ramdisk subimage node offset
1804 -125 common/image.c Ramdisk subimage hash verification failed
1805 126 common/image.c Ramdisk subimage hash verification OK
1806 -126 common/image.c Ramdisk subimage for unsupported architecture
1807 127 common/image.c Architecture check OK
1808 -127 common/image.c Can't get ramdisk subimage data/size
1809 128 common/image.c Got ramdisk subimage data/size
1810 129 common/image.c Can't get ramdisk load address
1811 -129 common/image.c Got ramdisk load address
1813 -130 common/cmd_doc.c Icorrect FIT image format
1814 131 common/cmd_doc.c FIT image format OK
1816 -140 common/cmd_ide.c Icorrect FIT image format
1817 141 common/cmd_ide.c FIT image format OK
1819 -150 common/cmd_nand.c Icorrect FIT image format
1820 151 common/cmd_nand.c FIT image format OK
1826 [so far only for SMDK2400 and TRAB boards]
1828 - Modem support endable:
1829 CONFIG_MODEM_SUPPORT
1831 - RTS/CTS Flow control enable:
1834 - Modem debug support:
1835 CONFIG_MODEM_SUPPORT_DEBUG
1837 Enables debugging stuff (char screen[1024], dbg())
1838 for modem support. Useful only with BDI2000.
1840 - Interrupt support (PPC):
1842 There are common interrupt_init() and timer_interrupt()
1843 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1844 for cpu specific initialization. interrupt_init_cpu()
1845 should set decrementer_count to appropriate value. If
1846 cpu resets decrementer automatically after interrupt
1847 (ppc4xx) it should set decrementer_count to zero.
1848 timer_interrupt() calls timer_interrupt_cpu() for cpu
1849 specific handling. If board has watchdog / status_led
1850 / other_activity_monitor it works automatically from
1851 general timer_interrupt().
1855 In the target system modem support is enabled when a
1856 specific key (key combination) is pressed during
1857 power-on. Otherwise U-Boot will boot normally
1858 (autoboot). The key_pressed() fuction is called from
1859 board_init(). Currently key_pressed() is a dummy
1860 function, returning 1 and thus enabling modem
1863 If there are no modem init strings in the
1864 environment, U-Boot proceed to autoboot; the
1865 previous output (banner, info printfs) will be
1868 See also: doc/README.Modem
1871 Configuration Settings:
1872 -----------------------
1874 - CFG_LONGHELP: Defined when you want long help messages included;
1875 undefine this when you're short of memory.
1877 - CFG_PROMPT: This is what U-Boot prints on the console to
1878 prompt for user input.
1880 - CFG_CBSIZE: Buffer size for input from the Console
1882 - CFG_PBSIZE: Buffer size for Console output
1884 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1886 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1887 the application (usually a Linux kernel) when it is
1890 - CFG_BAUDRATE_TABLE:
1891 List of legal baudrate settings for this board.
1893 - CFG_CONSOLE_INFO_QUIET
1894 Suppress display of console information at boot.
1896 - CFG_CONSOLE_IS_IN_ENV
1897 If the board specific function
1898 extern int overwrite_console (void);
1899 returns 1, the stdin, stderr and stdout are switched to the
1900 serial port, else the settings in the environment are used.
1902 - CFG_CONSOLE_OVERWRITE_ROUTINE
1903 Enable the call to overwrite_console().
1905 - CFG_CONSOLE_ENV_OVERWRITE
1906 Enable overwrite of previous console environment settings.
1908 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1909 Begin and End addresses of the area used by the
1913 Enable an alternate, more extensive memory test.
1915 - CFG_MEMTEST_SCRATCH:
1916 Scratch address used by the alternate memory test
1917 You only need to set this if address zero isn't writeable
1919 - CFG_TFTP_LOADADDR:
1920 Default load address for network file downloads
1922 - CFG_LOADS_BAUD_CHANGE:
1923 Enable temporary baudrate change while serial download
1926 Physical start address of SDRAM. _Must_ be 0 here.
1929 Physical start address of Motherboard I/O (if using a
1933 Physical start address of Flash memory.
1936 Physical start address of boot monitor code (set by
1937 make config files to be same as the text base address
1938 (TEXT_BASE) used when linking) - same as
1939 CFG_FLASH_BASE when booting from flash.
1942 Size of memory reserved for monitor code, used to
1943 determine _at_compile_time_ (!) if the environment is
1944 embedded within the U-Boot image, or in a separate
1948 Size of DRAM reserved for malloc() use.
1951 Normally compressed uImages are limited to an
1952 uncompressed size of 8 MBytes. If this is not enough,
1953 you can define CFG_BOOTM_LEN in your board config file
1954 to adjust this setting to your needs.
1957 Maximum size of memory mapped by the startup code of
1958 the Linux kernel; all data that must be processed by
1959 the Linux kernel (bd_info, boot arguments, eventually
1960 initrd image) must be put below this limit.
1962 - CFG_MAX_FLASH_BANKS:
1963 Max number of Flash memory banks
1965 - CFG_MAX_FLASH_SECT:
1966 Max number of sectors on a Flash chip
1968 - CFG_FLASH_ERASE_TOUT:
1969 Timeout for Flash erase operations (in ms)
1971 - CFG_FLASH_WRITE_TOUT:
1972 Timeout for Flash write operations (in ms)
1974 - CFG_FLASH_LOCK_TOUT
1975 Timeout for Flash set sector lock bit operation (in ms)
1977 - CFG_FLASH_UNLOCK_TOUT
1978 Timeout for Flash clear lock bits operation (in ms)
1980 - CFG_FLASH_PROTECTION
1981 If defined, hardware flash sectors protection is used
1982 instead of U-Boot software protection.
1984 - CFG_DIRECT_FLASH_TFTP:
1986 Enable TFTP transfers directly to flash memory;
1987 without this option such a download has to be
1988 performed in two steps: (1) download to RAM, and (2)
1989 copy from RAM to flash.
1991 The two-step approach is usually more reliable, since
1992 you can check if the download worked before you erase
1993 the flash, but in some situations (when sytem RAM is
1994 too limited to allow for a tempory copy of the
1995 downloaded image) this option may be very useful.
1998 Define if the flash driver uses extra elements in the
1999 common flash structure for storing flash geometry.
2001 - CFG_FLASH_CFI_DRIVER
2002 This option also enables the building of the cfi_flash driver
2003 in the drivers directory
2005 - CFG_FLASH_QUIET_TEST
2006 If this option is defined, the common CFI flash doesn't
2007 print it's warning upon not recognized FLASH banks. This
2008 is useful, if some of the configured banks are only
2009 optionally available.
2011 - CONFIG_FLASH_SHOW_PROGRESS
2012 If defined (must be an integer), print out countdown
2013 digits and dots. Recommended value: 45 (9..1) for 80
2014 column displays, 15 (3..1) for 40 column displays.
2016 - CFG_RX_ETH_BUFFER:
2017 Defines the number of ethernet receive buffers. On some
2018 ethernet controllers it is recommended to set this value
2019 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2020 buffers can be full shortly after enabling the interface
2021 on high ethernet traffic.
2022 Defaults to 4 if not defined.
2024 The following definitions that deal with the placement and management
2025 of environment data (variable area); in general, we support the
2026 following configurations:
2028 - CFG_ENV_IS_IN_FLASH:
2030 Define this if the environment is in flash memory.
2032 a) The environment occupies one whole flash sector, which is
2033 "embedded" in the text segment with the U-Boot code. This
2034 happens usually with "bottom boot sector" or "top boot
2035 sector" type flash chips, which have several smaller
2036 sectors at the start or the end. For instance, such a
2037 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2038 such a case you would place the environment in one of the
2039 4 kB sectors - with U-Boot code before and after it. With
2040 "top boot sector" type flash chips, you would put the
2041 environment in one of the last sectors, leaving a gap
2042 between U-Boot and the environment.
2046 Offset of environment data (variable area) to the
2047 beginning of flash memory; for instance, with bottom boot
2048 type flash chips the second sector can be used: the offset
2049 for this sector is given here.
2051 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2055 This is just another way to specify the start address of
2056 the flash sector containing the environment (instead of
2059 - CFG_ENV_SECT_SIZE:
2061 Size of the sector containing the environment.
2064 b) Sometimes flash chips have few, equal sized, BIG sectors.
2065 In such a case you don't want to spend a whole sector for
2070 If you use this in combination with CFG_ENV_IS_IN_FLASH
2071 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2072 of this flash sector for the environment. This saves
2073 memory for the RAM copy of the environment.
2075 It may also save flash memory if you decide to use this
2076 when your environment is "embedded" within U-Boot code,
2077 since then the remainder of the flash sector could be used
2078 for U-Boot code. It should be pointed out that this is
2079 STRONGLY DISCOURAGED from a robustness point of view:
2080 updating the environment in flash makes it always
2081 necessary to erase the WHOLE sector. If something goes
2082 wrong before the contents has been restored from a copy in
2083 RAM, your target system will be dead.
2085 - CFG_ENV_ADDR_REDUND
2088 These settings describe a second storage area used to hold
2089 a redundand copy of the environment data, so that there is
2090 a valid backup copy in case there is a power failure during
2091 a "saveenv" operation.
2093 BE CAREFUL! Any changes to the flash layout, and some changes to the
2094 source code will make it necessary to adapt <board>/u-boot.lds*
2098 - CFG_ENV_IS_IN_NVRAM:
2100 Define this if you have some non-volatile memory device
2101 (NVRAM, battery buffered SRAM) which you want to use for the
2107 These two #defines are used to determin the memory area you
2108 want to use for environment. It is assumed that this memory
2109 can just be read and written to, without any special
2112 BE CAREFUL! The first access to the environment happens quite early
2113 in U-Boot initalization (when we try to get the setting of for the
2114 console baudrate). You *MUST* have mappend your NVRAM area then, or
2117 Please note that even with NVRAM we still use a copy of the
2118 environment in RAM: we could work on NVRAM directly, but we want to
2119 keep settings there always unmodified except somebody uses "saveenv"
2120 to save the current settings.
2123 - CFG_ENV_IS_IN_EEPROM:
2125 Use this if you have an EEPROM or similar serial access
2126 device and a driver for it.
2131 These two #defines specify the offset and size of the
2132 environment area within the total memory of your EEPROM.
2134 - CFG_I2C_EEPROM_ADDR:
2135 If defined, specified the chip address of the EEPROM device.
2136 The default address is zero.
2138 - CFG_EEPROM_PAGE_WRITE_BITS:
2139 If defined, the number of bits used to address bytes in a
2140 single page in the EEPROM device. A 64 byte page, for example
2141 would require six bits.
2143 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2144 If defined, the number of milliseconds to delay between
2145 page writes. The default is zero milliseconds.
2147 - CFG_I2C_EEPROM_ADDR_LEN:
2148 The length in bytes of the EEPROM memory array address. Note
2149 that this is NOT the chip address length!
2151 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2152 EEPROM chips that implement "address overflow" are ones
2153 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2154 address and the extra bits end up in the "chip address" bit
2155 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2158 Note that we consider the length of the address field to
2159 still be one byte because the extra address bits are hidden
2160 in the chip address.
2163 The size in bytes of the EEPROM device.
2166 - CFG_ENV_IS_IN_DATAFLASH:
2168 Define this if you have a DataFlash memory device which you
2169 want to use for the environment.
2175 These three #defines specify the offset and size of the
2176 environment area within the total memory of your DataFlash placed
2177 at the specified address.
2179 - CFG_ENV_IS_IN_NAND:
2181 Define this if you have a NAND device which you want to use
2182 for the environment.
2187 These two #defines specify the offset and size of the environment
2188 area within the first NAND device.
2190 - CFG_ENV_OFFSET_REDUND
2192 This setting describes a second storage area of CFG_ENV_SIZE
2193 size used to hold a redundant copy of the environment data,
2194 so that there is a valid backup copy in case there is a
2195 power failure during a "saveenv" operation.
2197 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2198 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2199 the NAND devices block size.
2201 - CFG_SPI_INIT_OFFSET
2203 Defines offset to the initial SPI buffer area in DPRAM. The
2204 area is used at an early stage (ROM part) if the environment
2205 is configured to reside in the SPI EEPROM: We need a 520 byte
2206 scratch DPRAM area. It is used between the two initialization
2207 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2208 to be a good choice since it makes it far enough from the
2209 start of the data area as well as from the stack pointer.
2211 Please note that the environment is read-only until the monitor
2212 has been relocated to RAM and a RAM copy of the environment has been
2213 created; also, when using EEPROM you will have to use getenv_r()
2214 until then to read environment variables.
2216 The environment is protected by a CRC32 checksum. Before the monitor
2217 is relocated into RAM, as a result of a bad CRC you will be working
2218 with the compiled-in default environment - *silently*!!! [This is
2219 necessary, because the first environment variable we need is the
2220 "baudrate" setting for the console - if we have a bad CRC, we don't
2221 have any device yet where we could complain.]
2223 Note: once the monitor has been relocated, then it will complain if
2224 the default environment is used; a new CRC is computed as soon as you
2225 use the "saveenv" command to store a valid environment.
2227 - CFG_FAULT_ECHO_LINK_DOWN:
2228 Echo the inverted Ethernet link state to the fault LED.
2230 Note: If this option is active, then CFG_FAULT_MII_ADDR
2231 also needs to be defined.
2233 - CFG_FAULT_MII_ADDR:
2234 MII address of the PHY to check for the Ethernet link state.
2236 - CFG_64BIT_VSPRINTF:
2237 Makes vsprintf (and all *printf functions) support printing
2238 of 64bit values by using the L quantifier
2240 - CFG_64BIT_STRTOUL:
2241 Adds simple_strtoull that returns a 64bit value
2243 Low Level (hardware related) configuration options:
2244 ---------------------------------------------------
2246 - CFG_CACHELINE_SIZE:
2247 Cache Line Size of the CPU.
2250 Default address of the IMMR after system reset.
2252 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2253 and RPXsuper) to be able to adjust the position of
2254 the IMMR register after a reset.
2256 - Floppy Disk Support:
2257 CFG_FDC_DRIVE_NUMBER
2259 the default drive number (default value 0)
2263 defines the spacing between fdc chipset registers
2268 defines the offset of register from address. It
2269 depends on which part of the data bus is connected to
2270 the fdc chipset. (default value 0)
2272 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2273 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2276 if CFG_FDC_HW_INIT is defined, then the function
2277 fdc_hw_init() is called at the beginning of the FDC
2278 setup. fdc_hw_init() must be provided by the board
2279 source code. It is used to make hardware dependant
2282 - CFG_IMMR: Physical address of the Internal Memory.
2283 DO NOT CHANGE unless you know exactly what you're
2284 doing! (11-4) [MPC8xx/82xx systems only]
2286 - CFG_INIT_RAM_ADDR:
2288 Start address of memory area that can be used for
2289 initial data and stack; please note that this must be
2290 writable memory that is working WITHOUT special
2291 initialization, i. e. you CANNOT use normal RAM which
2292 will become available only after programming the
2293 memory controller and running certain initialization
2296 U-Boot uses the following memory types:
2297 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2298 - MPC824X: data cache
2299 - PPC4xx: data cache
2301 - CFG_GBL_DATA_OFFSET:
2303 Offset of the initial data structure in the memory
2304 area defined by CFG_INIT_RAM_ADDR. Usually
2305 CFG_GBL_DATA_OFFSET is chosen such that the initial
2306 data is located at the end of the available space
2307 (sometimes written as (CFG_INIT_RAM_END -
2308 CFG_INIT_DATA_SIZE), and the initial stack is just
2309 below that area (growing from (CFG_INIT_RAM_ADDR +
2310 CFG_GBL_DATA_OFFSET) downward.
2313 On the MPC824X (or other systems that use the data
2314 cache for initial memory) the address chosen for
2315 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2316 point to an otherwise UNUSED address space between
2317 the top of RAM and the start of the PCI space.
2319 - CFG_SIUMCR: SIU Module Configuration (11-6)
2321 - CFG_SYPCR: System Protection Control (11-9)
2323 - CFG_TBSCR: Time Base Status and Control (11-26)
2325 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2327 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2329 - CFG_SCCR: System Clock and reset Control Register (15-27)
2331 - CFG_OR_TIMING_SDRAM:
2335 periodic timer for refresh
2337 - CFG_DER: Debug Event Register (37-47)
2339 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2340 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2341 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2343 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2345 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2346 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2347 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2348 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2350 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2351 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2352 Machine Mode Register and Memory Periodic Timer
2353 Prescaler definitions (SDRAM timing)
2355 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2356 enable I2C microcode relocation patch (MPC8xx);
2357 define relocation offset in DPRAM [DSP2]
2359 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2360 enable SMC microcode relocation patch (MPC8xx);
2361 define relocation offset in DPRAM [SMC1]
2363 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2364 enable SPI microcode relocation patch (MPC8xx);
2365 define relocation offset in DPRAM [SCC4]
2368 Use OSCM clock mode on MBX8xx board. Be careful,
2369 wrong setting might damage your board. Read
2370 doc/README.MBX before setting this variable!
2372 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2373 Offset of the bootmode word in DPRAM used by post
2374 (Power On Self Tests). This definition overrides
2375 #define'd default value in commproc.h resp.
2378 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2379 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2380 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2381 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2382 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2383 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2384 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2385 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2386 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2389 Get DDR timing information from an I2C EEPROM. Common
2390 with pluggable memory modules such as SODIMMs
2393 I2C address of the SPD EEPROM
2396 If SPD EEPROM is on an I2C bus other than the first
2397 one, specify here. Note that the value must resolve
2398 to something your driver can deal with.
2400 - CFG_83XX_DDR_USES_CS0
2401 Only for 83xx systems. If specified, then DDR should
2402 be configured using CS0 and CS1 instead of CS2 and CS3.
2404 - CFG_83XX_DDR_USES_CS0
2405 Only for 83xx systems. If specified, then DDR should
2406 be configured using CS0 and CS1 instead of CS2 and CS3.
2408 - CONFIG_ETHER_ON_FEC[12]
2409 Define to enable FEC[12] on a 8xx series processor.
2411 - CONFIG_FEC[12]_PHY
2412 Define to the hardcoded PHY address which corresponds
2413 to the given FEC; i. e.
2414 #define CONFIG_FEC1_PHY 4
2415 means that the PHY with address 4 is connected to FEC1
2417 When set to -1, means to probe for first available.
2419 - CONFIG_FEC[12]_PHY_NORXERR
2420 The PHY does not have a RXERR line (RMII only).
2421 (so program the FEC to ignore it).
2424 Enable RMII mode for all FECs.
2425 Note that this is a global option, we can't
2426 have one FEC in standard MII mode and another in RMII mode.
2428 - CONFIG_CRC32_VERIFY
2429 Add a verify option to the crc32 command.
2432 => crc32 -v <address> <count> <crc32>
2434 Where address/count indicate a memory area
2435 and crc32 is the correct crc32 which the
2439 Add the "loopw" memory command. This only takes effect if
2440 the memory commands are activated globally (CONFIG_CMD_MEM).
2443 Add the "mdc" and "mwc" memory commands. These are cyclic
2448 This command will print 4 bytes (10,11,12,13) each 500 ms.
2450 => mwc.l 100 12345678 10
2451 This command will write 12345678 to address 100 all 10 ms.
2453 This only takes effect if the memory commands are activated
2454 globally (CONFIG_CMD_MEM).
2456 - CONFIG_SKIP_LOWLEVEL_INIT
2457 - CONFIG_SKIP_RELOCATE_UBOOT
2459 [ARM only] If these variables are defined, then
2460 certain low level initializations (like setting up
2461 the memory controller) are omitted and/or U-Boot does
2462 not relocate itself into RAM.
2463 Normally these variables MUST NOT be defined. The
2464 only exception is when U-Boot is loaded (to RAM) by
2465 some other boot loader or by a debugger which
2466 performs these intializations itself.
2469 Building the Software:
2470 ======================
2472 Building U-Boot has been tested in several native build environments
2473 and in many different cross environments. Of course we cannot support
2474 all possibly existing versions of cross development tools in all
2475 (potentially obsolete) versions. In case of tool chain problems we
2476 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2477 which is extensively used to build and test U-Boot.
2479 If you are not using a native environment, it is assumed that you
2480 have GNU cross compiling tools available in your path. In this case,
2481 you must set the environment variable CROSS_COMPILE in your shell.
2482 Note that no changes to the Makefile or any other source files are
2483 necessary. For example using the ELDK on a 4xx CPU, please enter:
2485 $ CROSS_COMPILE=ppc_4xx-
2486 $ export CROSS_COMPILE
2488 U-Boot is intended to be simple to build. After installing the
2489 sources you must configure U-Boot for one specific board type. This
2494 where "NAME_config" is the name of one of the existing configu-
2495 rations; see the main Makefile for supported names.
2497 Note: for some board special configuration names may exist; check if
2498 additional information is available from the board vendor; for
2499 instance, the TQM823L systems are available without (standard)
2500 or with LCD support. You can select such additional "features"
2501 when chosing the configuration, i. e.
2504 - will configure for a plain TQM823L, i. e. no LCD support
2506 make TQM823L_LCD_config
2507 - will configure for a TQM823L with U-Boot console on LCD
2512 Finally, type "make all", and you should get some working U-Boot
2513 images ready for download to / installation on your system:
2515 - "u-boot.bin" is a raw binary image
2516 - "u-boot" is an image in ELF binary format
2517 - "u-boot.srec" is in Motorola S-Record format
2519 By default the build is performed locally and the objects are saved
2520 in the source directory. One of the two methods can be used to change
2521 this behavior and build U-Boot to some external directory:
2523 1. Add O= to the make command line invocations:
2525 make O=/tmp/build distclean
2526 make O=/tmp/build NAME_config
2527 make O=/tmp/build all
2529 2. Set environment variable BUILD_DIR to point to the desired location:
2531 export BUILD_DIR=/tmp/build
2536 Note that the command line "O=" setting overrides the BUILD_DIR environment
2540 Please be aware that the Makefiles assume you are using GNU make, so
2541 for instance on NetBSD you might need to use "gmake" instead of
2545 If the system board that you have is not listed, then you will need
2546 to port U-Boot to your hardware platform. To do this, follow these
2549 1. Add a new configuration option for your board to the toplevel
2550 "Makefile" and to the "MAKEALL" script, using the existing
2551 entries as examples. Note that here and at many other places
2552 boards and other names are listed in alphabetical sort order. Please
2554 2. Create a new directory to hold your board specific code. Add any
2555 files you need. In your board directory, you will need at least
2556 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2557 3. Create a new configuration file "include/configs/<board>.h" for
2559 3. If you're porting U-Boot to a new CPU, then also create a new
2560 directory to hold your CPU specific code. Add any files you need.
2561 4. Run "make <board>_config" with your new name.
2562 5. Type "make", and you should get a working "u-boot.srec" file
2563 to be installed on your target system.
2564 6. Debug and solve any problems that might arise.
2565 [Of course, this last step is much harder than it sounds.]
2568 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2569 ==============================================================
2571 If you have modified U-Boot sources (for instance added a new board
2572 or support for new devices, a new CPU, etc.) you are expected to
2573 provide feedback to the other developers. The feedback normally takes
2574 the form of a "patch", i. e. a context diff against a certain (latest
2575 official or latest in the git repository) version of U-Boot sources.
2577 But before you submit such a patch, please verify that your modifi-
2578 cation did not break existing code. At least make sure that *ALL* of
2579 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2580 just run the "MAKEALL" script, which will configure and build U-Boot
2581 for ALL supported system. Be warned, this will take a while. You can
2582 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2583 environment variable to the script, i. e. to use the ELDK cross tools
2586 CROSS_COMPILE=ppc_8xx- MAKEALL
2588 or to build on a native PowerPC system you can type
2590 CROSS_COMPILE=' ' MAKEALL
2592 When using the MAKEALL script, the default behaviour is to build
2593 U-Boot in the source directory. This location can be changed by
2594 setting the BUILD_DIR environment variable. Also, for each target
2595 built, the MAKEALL script saves two log files (<target>.ERR and
2596 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2597 location can be changed by setting the MAKEALL_LOGDIR environment
2598 variable. For example:
2600 export BUILD_DIR=/tmp/build
2601 export MAKEALL_LOGDIR=/tmp/log
2602 CROSS_COMPILE=ppc_8xx- MAKEALL
2604 With the above settings build objects are saved in the /tmp/build,
2605 log files are saved in the /tmp/log and the source tree remains clean
2606 during the whole build process.
2609 See also "U-Boot Porting Guide" below.
2612 Monitor Commands - Overview:
2613 ============================
2615 go - start application at address 'addr'
2616 run - run commands in an environment variable
2617 bootm - boot application image from memory
2618 bootp - boot image via network using BootP/TFTP protocol
2619 tftpboot- boot image via network using TFTP protocol
2620 and env variables "ipaddr" and "serverip"
2621 (and eventually "gatewayip")
2622 rarpboot- boot image via network using RARP/TFTP protocol
2623 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2624 loads - load S-Record file over serial line
2625 loadb - load binary file over serial line (kermit mode)
2627 mm - memory modify (auto-incrementing)
2628 nm - memory modify (constant address)
2629 mw - memory write (fill)
2631 cmp - memory compare
2632 crc32 - checksum calculation
2633 imd - i2c memory display
2634 imm - i2c memory modify (auto-incrementing)
2635 inm - i2c memory modify (constant address)
2636 imw - i2c memory write (fill)
2637 icrc32 - i2c checksum calculation
2638 iprobe - probe to discover valid I2C chip addresses
2639 iloop - infinite loop on address range
2640 isdram - print SDRAM configuration information
2641 sspi - SPI utility commands
2642 base - print or set address offset
2643 printenv- print environment variables
2644 setenv - set environment variables
2645 saveenv - save environment variables to persistent storage
2646 protect - enable or disable FLASH write protection
2647 erase - erase FLASH memory
2648 flinfo - print FLASH memory information
2649 bdinfo - print Board Info structure
2650 iminfo - print header information for application image
2651 coninfo - print console devices and informations
2652 ide - IDE sub-system
2653 loop - infinite loop on address range
2654 loopw - infinite write loop on address range
2655 mtest - simple RAM test
2656 icache - enable or disable instruction cache
2657 dcache - enable or disable data cache
2658 reset - Perform RESET of the CPU
2659 echo - echo args to console
2660 version - print monitor version
2661 help - print online help
2662 ? - alias for 'help'
2665 Monitor Commands - Detailed Description:
2666 ========================================
2670 For now: just type "help <command>".
2673 Environment Variables:
2674 ======================
2676 U-Boot supports user configuration using Environment Variables which
2677 can be made persistent by saving to Flash memory.
2679 Environment Variables are set using "setenv", printed using
2680 "printenv", and saved to Flash using "saveenv". Using "setenv"
2681 without a value can be used to delete a variable from the
2682 environment. As long as you don't save the environment you are
2683 working with an in-memory copy. In case the Flash area containing the
2684 environment is erased by accident, a default environment is provided.
2686 Some configuration options can be set using Environment Variables:
2688 baudrate - see CONFIG_BAUDRATE
2690 bootdelay - see CONFIG_BOOTDELAY
2692 bootcmd - see CONFIG_BOOTCOMMAND
2694 bootargs - Boot arguments when booting an RTOS image
2696 bootfile - Name of the image to load with TFTP
2698 autoload - if set to "no" (any string beginning with 'n'),
2699 "bootp" will just load perform a lookup of the
2700 configuration from the BOOTP server, but not try to
2701 load any image using TFTP
2703 autoscript - if set to "yes" commands like "loadb", "loady",
2704 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2705 to automatically run script images (by internally
2706 calling "autoscript").
2708 autoscript_uname - if script image is in a format (FIT) this
2709 variable is used to get script subimage unit name.
2711 autostart - if set to "yes", an image loaded using the "bootp",
2712 "rarpboot", "tftpboot" or "diskboot" commands will
2713 be automatically started (by internally calling
2716 If set to "no", a standalone image passed to the
2717 "bootm" command will be copied to the load address
2718 (and eventually uncompressed), but NOT be started.
2719 This can be used to load and uncompress arbitrary
2722 i2cfast - (PPC405GP|PPC405EP only)
2723 if set to 'y' configures Linux I2C driver for fast
2724 mode (400kHZ). This environment variable is used in
2725 initialization code. So, for changes to be effective
2726 it must be saved and board must be reset.
2728 initrd_high - restrict positioning of initrd images:
2729 If this variable is not set, initrd images will be
2730 copied to the highest possible address in RAM; this
2731 is usually what you want since it allows for
2732 maximum initrd size. If for some reason you want to
2733 make sure that the initrd image is loaded below the
2734 CFG_BOOTMAPSZ limit, you can set this environment
2735 variable to a value of "no" or "off" or "0".
2736 Alternatively, you can set it to a maximum upper
2737 address to use (U-Boot will still check that it
2738 does not overwrite the U-Boot stack and data).
2740 For instance, when you have a system with 16 MB
2741 RAM, and want to reserve 4 MB from use by Linux,
2742 you can do this by adding "mem=12M" to the value of
2743 the "bootargs" variable. However, now you must make
2744 sure that the initrd image is placed in the first
2745 12 MB as well - this can be done with
2747 setenv initrd_high 00c00000
2749 If you set initrd_high to 0xFFFFFFFF, this is an
2750 indication to U-Boot that all addresses are legal
2751 for the Linux kernel, including addresses in flash
2752 memory. In this case U-Boot will NOT COPY the
2753 ramdisk at all. This may be useful to reduce the
2754 boot time on your system, but requires that this
2755 feature is supported by your Linux kernel.
2757 ipaddr - IP address; needed for tftpboot command
2759 loadaddr - Default load address for commands like "bootp",
2760 "rarpboot", "tftpboot", "loadb" or "diskboot"
2762 loads_echo - see CONFIG_LOADS_ECHO
2764 serverip - TFTP server IP address; needed for tftpboot command
2766 bootretry - see CONFIG_BOOT_RETRY_TIME
2768 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2770 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2772 ethprime - When CONFIG_NET_MULTI is enabled controls which
2773 interface is used first.
2775 ethact - When CONFIG_NET_MULTI is enabled controls which
2776 interface is currently active. For example you
2777 can do the following
2779 => setenv ethact FEC ETHERNET
2780 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2781 => setenv ethact SCC ETHERNET
2782 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2784 ethrotate - When set to "no" U-Boot does not go through all
2785 available network interfaces.
2786 It just stays at the currently selected interface.
2788 netretry - When set to "no" each network operation will
2789 either succeed or fail without retrying.
2790 When set to "once" the network operation will
2791 fail when all the available network interfaces
2792 are tried once without success.
2793 Useful on scripts which control the retry operation
2796 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2797 if set load address for the npe microcode
2799 tftpsrcport - If this is set, the value is used for TFTP's
2802 tftpdstport - If this is set, the value is used for TFTP's UDP
2803 destination port instead of the Well Know Port 69.
2805 vlan - When set to a value < 4095 the traffic over
2806 ethernet is encapsulated/received over 802.1q
2809 The following environment variables may be used and automatically
2810 updated by the network boot commands ("bootp" and "rarpboot"),
2811 depending the information provided by your boot server:
2813 bootfile - see above
2814 dnsip - IP address of your Domain Name Server
2815 dnsip2 - IP address of your secondary Domain Name Server
2816 gatewayip - IP address of the Gateway (Router) to use
2817 hostname - Target hostname
2819 netmask - Subnet Mask
2820 rootpath - Pathname of the root filesystem on the NFS server
2821 serverip - see above
2824 There are two special Environment Variables:
2826 serial# - contains hardware identification information such
2827 as type string and/or serial number
2828 ethaddr - Ethernet address
2830 These variables can be set only once (usually during manufacturing of
2831 the board). U-Boot refuses to delete or overwrite these variables
2832 once they have been set once.
2835 Further special Environment Variables:
2837 ver - Contains the U-Boot version string as printed
2838 with the "version" command. This variable is
2839 readonly (see CONFIG_VERSION_VARIABLE).
2842 Please note that changes to some configuration parameters may take
2843 only effect after the next boot (yes, that's just like Windoze :-).
2846 Command Line Parsing:
2847 =====================
2849 There are two different command line parsers available with U-Boot:
2850 the old "simple" one, and the much more powerful "hush" shell:
2852 Old, simple command line parser:
2853 --------------------------------
2855 - supports environment variables (through setenv / saveenv commands)
2856 - several commands on one line, separated by ';'
2857 - variable substitution using "... ${name} ..." syntax
2858 - special characters ('$', ';') can be escaped by prefixing with '\',
2860 setenv bootcmd bootm \${address}
2861 - You can also escape text by enclosing in single apostrophes, for example:
2862 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2867 - similar to Bourne shell, with control structures like
2868 if...then...else...fi, for...do...done; while...do...done,
2869 until...do...done, ...
2870 - supports environment ("global") variables (through setenv / saveenv
2871 commands) and local shell variables (through standard shell syntax
2872 "name=value"); only environment variables can be used with "run"
2878 (1) If a command line (or an environment variable executed by a "run"
2879 command) contains several commands separated by semicolon, and
2880 one of these commands fails, then the remaining commands will be
2883 (2) If you execute several variables with one call to run (i. e.
2884 calling run with a list af variables as arguments), any failing
2885 command will cause "run" to terminate, i. e. the remaining
2886 variables are not executed.
2888 Note for Redundant Ethernet Interfaces:
2889 =======================================
2891 Some boards come with redundant ethernet interfaces; U-Boot supports
2892 such configurations and is capable of automatic selection of a
2893 "working" interface when needed. MAC assignment works as follows:
2895 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2896 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2897 "eth1addr" (=>eth1), "eth2addr", ...
2899 If the network interface stores some valid MAC address (for instance
2900 in SROM), this is used as default address if there is NO correspon-
2901 ding setting in the environment; if the corresponding environment
2902 variable is set, this overrides the settings in the card; that means:
2904 o If the SROM has a valid MAC address, and there is no address in the
2905 environment, the SROM's address is used.
2907 o If there is no valid address in the SROM, and a definition in the
2908 environment exists, then the value from the environment variable is
2911 o If both the SROM and the environment contain a MAC address, and
2912 both addresses are the same, this MAC address is used.
2914 o If both the SROM and the environment contain a MAC address, and the
2915 addresses differ, the value from the environment is used and a
2918 o If neither SROM nor the environment contain a MAC address, an error
2925 U-Boot is capable of booting (and performing other auxiliary operations on)
2926 images in two formats:
2928 New uImage format (FIT)
2929 -----------------------
2931 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
2932 to Flattened Device Tree). It allows the use of images with multiple
2933 components (several kernels, ramdisks, etc.), with contents protected by
2934 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
2940 Old image format is based on binary files which can be basically anything,
2941 preceded by a special header; see the definitions in include/image.h for
2942 details; basically, the header defines the following image properties:
2944 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2945 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2946 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2947 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2948 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2949 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2950 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2951 * Compression Type (uncompressed, gzip, bzip2)
2957 The header is marked by a special Magic Number, and both the header
2958 and the data portions of the image are secured against corruption by
2965 Although U-Boot should support any OS or standalone application
2966 easily, the main focus has always been on Linux during the design of
2969 U-Boot includes many features that so far have been part of some
2970 special "boot loader" code within the Linux kernel. Also, any
2971 "initrd" images to be used are no longer part of one big Linux image;
2972 instead, kernel and "initrd" are separate images. This implementation
2973 serves several purposes:
2975 - the same features can be used for other OS or standalone
2976 applications (for instance: using compressed images to reduce the
2977 Flash memory footprint)
2979 - it becomes much easier to port new Linux kernel versions because
2980 lots of low-level, hardware dependent stuff are done by U-Boot
2982 - the same Linux kernel image can now be used with different "initrd"
2983 images; of course this also means that different kernel images can
2984 be run with the same "initrd". This makes testing easier (you don't
2985 have to build a new "zImage.initrd" Linux image when you just
2986 change a file in your "initrd"). Also, a field-upgrade of the
2987 software is easier now.
2993 Porting Linux to U-Boot based systems:
2994 ---------------------------------------
2996 U-Boot cannot save you from doing all the necessary modifications to
2997 configure the Linux device drivers for use with your target hardware
2998 (no, we don't intend to provide a full virtual machine interface to
3001 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3003 Just make sure your machine specific header file (for instance
3004 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3005 Information structure as we define in include/u-boot.h, and make
3006 sure that your definition of IMAP_ADDR uses the same value as your
3007 U-Boot configuration in CFG_IMMR.
3010 Configuring the Linux kernel:
3011 -----------------------------
3013 No specific requirements for U-Boot. Make sure you have some root
3014 device (initial ramdisk, NFS) for your target system.
3017 Building a Linux Image:
3018 -----------------------
3020 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3021 not used. If you use recent kernel source, a new build target
3022 "uImage" will exist which automatically builds an image usable by
3023 U-Boot. Most older kernels also have support for a "pImage" target,
3024 which was introduced for our predecessor project PPCBoot and uses a
3025 100% compatible format.
3034 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3035 encapsulate a compressed Linux kernel image with header information,
3036 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3038 * build a standard "vmlinux" kernel image (in ELF binary format):
3040 * convert the kernel into a raw binary image:
3042 ${CROSS_COMPILE}-objcopy -O binary \
3043 -R .note -R .comment \
3044 -S vmlinux linux.bin
3046 * compress the binary image:
3050 * package compressed binary image for U-Boot:
3052 mkimage -A ppc -O linux -T kernel -C gzip \
3053 -a 0 -e 0 -n "Linux Kernel Image" \
3054 -d linux.bin.gz uImage
3057 The "mkimage" tool can also be used to create ramdisk images for use
3058 with U-Boot, either separated from the Linux kernel image, or
3059 combined into one file. "mkimage" encapsulates the images with a 64
3060 byte header containing information about target architecture,
3061 operating system, image type, compression method, entry points, time
3062 stamp, CRC32 checksums, etc.
3064 "mkimage" can be called in two ways: to verify existing images and
3065 print the header information, or to build new images.
3067 In the first form (with "-l" option) mkimage lists the information
3068 contained in the header of an existing U-Boot image; this includes
3069 checksum verification:
3071 tools/mkimage -l image
3072 -l ==> list image header information
3074 The second form (with "-d" option) is used to build a U-Boot image
3075 from a "data file" which is used as image payload:
3077 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3078 -n name -d data_file image
3079 -A ==> set architecture to 'arch'
3080 -O ==> set operating system to 'os'
3081 -T ==> set image type to 'type'
3082 -C ==> set compression type 'comp'
3083 -a ==> set load address to 'addr' (hex)
3084 -e ==> set entry point to 'ep' (hex)
3085 -n ==> set image name to 'name'
3086 -d ==> use image data from 'datafile'
3088 Right now, all Linux kernels for PowerPC systems use the same load
3089 address (0x00000000), but the entry point address depends on the
3092 - 2.2.x kernels have the entry point at 0x0000000C,
3093 - 2.3.x and later kernels have the entry point at 0x00000000.
3095 So a typical call to build a U-Boot image would read:
3097 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3098 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3099 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3100 > examples/uImage.TQM850L
3101 Image Name: 2.4.4 kernel for TQM850L
3102 Created: Wed Jul 19 02:34:59 2000
3103 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3104 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3105 Load Address: 0x00000000
3106 Entry Point: 0x00000000
3108 To verify the contents of the image (or check for corruption):
3110 -> tools/mkimage -l examples/uImage.TQM850L
3111 Image Name: 2.4.4 kernel for TQM850L
3112 Created: Wed Jul 19 02:34:59 2000
3113 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3114 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3115 Load Address: 0x00000000
3116 Entry Point: 0x00000000
3118 NOTE: for embedded systems where boot time is critical you can trade
3119 speed for memory and install an UNCOMPRESSED image instead: this
3120 needs more space in Flash, but boots much faster since it does not
3121 need to be uncompressed:
3123 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3124 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3125 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3126 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3127 > examples/uImage.TQM850L-uncompressed
3128 Image Name: 2.4.4 kernel for TQM850L
3129 Created: Wed Jul 19 02:34:59 2000
3130 Image Type: PowerPC Linux Kernel Image (uncompressed)
3131 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3132 Load Address: 0x00000000
3133 Entry Point: 0x00000000
3136 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3137 when your kernel is intended to use an initial ramdisk:
3139 -> tools/mkimage -n 'Simple Ramdisk Image' \
3140 > -A ppc -O linux -T ramdisk -C gzip \
3141 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3142 Image Name: Simple Ramdisk Image
3143 Created: Wed Jan 12 14:01:50 2000
3144 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3145 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3146 Load Address: 0x00000000
3147 Entry Point: 0x00000000
3150 Installing a Linux Image:
3151 -------------------------
3153 To downloading a U-Boot image over the serial (console) interface,
3154 you must convert the image to S-Record format:
3156 objcopy -I binary -O srec examples/image examples/image.srec
3158 The 'objcopy' does not understand the information in the U-Boot
3159 image header, so the resulting S-Record file will be relative to
3160 address 0x00000000. To load it to a given address, you need to
3161 specify the target address as 'offset' parameter with the 'loads'
3164 Example: install the image to address 0x40100000 (which on the
3165 TQM8xxL is in the first Flash bank):
3167 => erase 40100000 401FFFFF
3173 ## Ready for S-Record download ...
3174 ~>examples/image.srec
3175 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3177 15989 15990 15991 15992
3178 [file transfer complete]
3180 ## Start Addr = 0x00000000
3183 You can check the success of the download using the 'iminfo' command;
3184 this includes a checksum verification so you can be sure no data
3185 corruption happened:
3189 ## Checking Image at 40100000 ...
3190 Image Name: 2.2.13 for initrd on TQM850L
3191 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3192 Data Size: 335725 Bytes = 327 kB = 0 MB
3193 Load Address: 00000000
3194 Entry Point: 0000000c
3195 Verifying Checksum ... OK
3201 The "bootm" command is used to boot an application that is stored in
3202 memory (RAM or Flash). In case of a Linux kernel image, the contents
3203 of the "bootargs" environment variable is passed to the kernel as
3204 parameters. You can check and modify this variable using the
3205 "printenv" and "setenv" commands:
3208 => printenv bootargs
3209 bootargs=root=/dev/ram
3211 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3213 => printenv bootargs
3214 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3217 ## Booting Linux kernel at 40020000 ...
3218 Image Name: 2.2.13 for NFS on TQM850L
3219 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3220 Data Size: 381681 Bytes = 372 kB = 0 MB
3221 Load Address: 00000000
3222 Entry Point: 0000000c
3223 Verifying Checksum ... OK
3224 Uncompressing Kernel Image ... OK
3225 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
3226 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3227 time_init: decrementer frequency = 187500000/60
3228 Calibrating delay loop... 49.77 BogoMIPS
3229 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3232 If you want to boot a Linux kernel with initial ram disk, you pass
3233 the memory addresses of both the kernel and the initrd image (PPBCOOT
3234 format!) to the "bootm" command:
3236 => imi 40100000 40200000
3238 ## Checking Image at 40100000 ...
3239 Image Name: 2.2.13 for initrd on TQM850L
3240 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3241 Data Size: 335725 Bytes = 327 kB = 0 MB
3242 Load Address: 00000000
3243 Entry Point: 0000000c
3244 Verifying Checksum ... OK
3246 ## Checking Image at 40200000 ...
3247 Image Name: Simple Ramdisk Image
3248 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3249 Data Size: 566530 Bytes = 553 kB = 0 MB
3250 Load Address: 00000000
3251 Entry Point: 00000000
3252 Verifying Checksum ... OK
3254 => bootm 40100000 40200000
3255 ## Booting Linux kernel at 40100000 ...
3256 Image Name: 2.2.13 for initrd on TQM850L
3257 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3258 Data Size: 335725 Bytes = 327 kB = 0 MB
3259 Load Address: 00000000
3260 Entry Point: 0000000c
3261 Verifying Checksum ... OK
3262 Uncompressing Kernel Image ... OK
3263 ## Loading RAMDisk Image at 40200000 ...
3264 Image Name: Simple Ramdisk Image
3265 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3266 Data Size: 566530 Bytes = 553 kB = 0 MB
3267 Load Address: 00000000
3268 Entry Point: 00000000
3269 Verifying Checksum ... OK
3270 Loading Ramdisk ... OK
3271 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
3272 Boot arguments: root=/dev/ram
3273 time_init: decrementer frequency = 187500000/60
3274 Calibrating delay loop... 49.77 BogoMIPS
3276 RAMDISK: Compressed image found at block 0
3277 VFS: Mounted root (ext2 filesystem).
3281 Boot Linux and pass a flat device tree:
3284 First, U-Boot must be compiled with the appropriate defines. See the section
3285 titled "Linux Kernel Interface" above for a more in depth explanation. The
3286 following is an example of how to start a kernel and pass an updated
3292 oft=oftrees/mpc8540ads.dtb
3293 => tftp $oftaddr $oft
3294 Speed: 1000, full duplex
3296 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3297 Filename 'oftrees/mpc8540ads.dtb'.
3298 Load address: 0x300000
3301 Bytes transferred = 4106 (100a hex)
3302 => tftp $loadaddr $bootfile
3303 Speed: 1000, full duplex
3305 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3307 Load address: 0x200000
3308 Loading:############
3310 Bytes transferred = 1029407 (fb51f hex)
3315 => bootm $loadaddr - $oftaddr
3316 ## Booting image at 00200000 ...
3317 Image Name: Linux-2.6.17-dirty
3318 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3319 Data Size: 1029343 Bytes = 1005.2 kB
3320 Load Address: 00000000
3321 Entry Point: 00000000
3322 Verifying Checksum ... OK
3323 Uncompressing Kernel Image ... OK
3324 Booting using flat device tree at 0x300000
3325 Using MPC85xx ADS machine description
3326 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3330 More About U-Boot Image Types:
3331 ------------------------------
3333 U-Boot supports the following image types:
3335 "Standalone Programs" are directly runnable in the environment
3336 provided by U-Boot; it is expected that (if they behave
3337 well) you can continue to work in U-Boot after return from
3338 the Standalone Program.
3339 "OS Kernel Images" are usually images of some Embedded OS which
3340 will take over control completely. Usually these programs
3341 will install their own set of exception handlers, device
3342 drivers, set up the MMU, etc. - this means, that you cannot
3343 expect to re-enter U-Boot except by resetting the CPU.
3344 "RAMDisk Images" are more or less just data blocks, and their
3345 parameters (address, size) are passed to an OS kernel that is
3347 "Multi-File Images" contain several images, typically an OS
3348 (Linux) kernel image and one or more data images like
3349 RAMDisks. This construct is useful for instance when you want
3350 to boot over the network using BOOTP etc., where the boot
3351 server provides just a single image file, but you want to get
3352 for instance an OS kernel and a RAMDisk image.
3354 "Multi-File Images" start with a list of image sizes, each
3355 image size (in bytes) specified by an "uint32_t" in network
3356 byte order. This list is terminated by an "(uint32_t)0".
3357 Immediately after the terminating 0 follow the images, one by
3358 one, all aligned on "uint32_t" boundaries (size rounded up to
3359 a multiple of 4 bytes).
3361 "Firmware Images" are binary images containing firmware (like
3362 U-Boot or FPGA images) which usually will be programmed to
3365 "Script files" are command sequences that will be executed by
3366 U-Boot's command interpreter; this feature is especially
3367 useful when you configure U-Boot to use a real shell (hush)
3368 as command interpreter.
3374 One of the features of U-Boot is that you can dynamically load and
3375 run "standalone" applications, which can use some resources of
3376 U-Boot like console I/O functions or interrupt services.
3378 Two simple examples are included with the sources:
3383 'examples/hello_world.c' contains a small "Hello World" Demo
3384 application; it is automatically compiled when you build U-Boot.
3385 It's configured to run at address 0x00040004, so you can play with it
3389 ## Ready for S-Record download ...
3390 ~>examples/hello_world.srec
3391 1 2 3 4 5 6 7 8 9 10 11 ...
3392 [file transfer complete]
3394 ## Start Addr = 0x00040004
3396 => go 40004 Hello World! This is a test.
3397 ## Starting application at 0x00040004 ...
3408 Hit any key to exit ...
3410 ## Application terminated, rc = 0x0
3412 Another example, which demonstrates how to register a CPM interrupt
3413 handler with the U-Boot code, can be found in 'examples/timer.c'.
3414 Here, a CPM timer is set up to generate an interrupt every second.
3415 The interrupt service routine is trivial, just printing a '.'
3416 character, but this is just a demo program. The application can be
3417 controlled by the following keys:
3419 ? - print current values og the CPM Timer registers
3420 b - enable interrupts and start timer
3421 e - stop timer and disable interrupts
3422 q - quit application
3425 ## Ready for S-Record download ...
3426 ~>examples/timer.srec
3427 1 2 3 4 5 6 7 8 9 10 11 ...
3428 [file transfer complete]
3430 ## Start Addr = 0x00040004
3433 ## Starting application at 0x00040004 ...
3436 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3439 [q, b, e, ?] Set interval 1000000 us
3442 [q, b, e, ?] ........
3443 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3446 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3449 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3452 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3454 [q, b, e, ?] ...Stopping timer
3456 [q, b, e, ?] ## Application terminated, rc = 0x0
3462 Over time, many people have reported problems when trying to use the
3463 "minicom" terminal emulation program for serial download. I (wd)
3464 consider minicom to be broken, and recommend not to use it. Under
3465 Unix, I recommend to use C-Kermit for general purpose use (and
3466 especially for kermit binary protocol download ("loadb" command), and
3467 use "cu" for S-Record download ("loads" command).
3469 Nevertheless, if you absolutely want to use it try adding this
3470 configuration to your "File transfer protocols" section:
3472 Name Program Name U/D FullScr IO-Red. Multi
3473 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3474 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3480 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3481 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3483 Building requires a cross environment; it is known to work on
3484 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3485 need gmake since the Makefiles are not compatible with BSD make).
3486 Note that the cross-powerpc package does not install include files;
3487 attempting to build U-Boot will fail because <machine/ansi.h> is
3488 missing. This file has to be installed and patched manually:
3490 # cd /usr/pkg/cross/powerpc-netbsd/include
3492 # ln -s powerpc machine
3493 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3494 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3496 Native builds *don't* work due to incompatibilities between native
3497 and U-Boot include files.
3499 Booting assumes that (the first part of) the image booted is a
3500 stage-2 loader which in turn loads and then invokes the kernel
3501 proper. Loader sources will eventually appear in the NetBSD source
3502 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3503 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3506 Implementation Internals:
3507 =========================
3509 The following is not intended to be a complete description of every
3510 implementation detail. However, it should help to understand the
3511 inner workings of U-Boot and make it easier to port it to custom
3515 Initial Stack, Global Data:
3516 ---------------------------
3518 The implementation of U-Boot is complicated by the fact that U-Boot
3519 starts running out of ROM (flash memory), usually without access to
3520 system RAM (because the memory controller is not initialized yet).
3521 This means that we don't have writable Data or BSS segments, and BSS
3522 is not initialized as zero. To be able to get a C environment working
3523 at all, we have to allocate at least a minimal stack. Implementation
3524 options for this are defined and restricted by the CPU used: Some CPU
3525 models provide on-chip memory (like the IMMR area on MPC8xx and
3526 MPC826x processors), on others (parts of) the data cache can be
3527 locked as (mis-) used as memory, etc.
3529 Chris Hallinan posted a good summary of these issues to the
3530 u-boot-users mailing list:
3532 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3533 From: "Chris Hallinan" <clh@net1plus.com>
3534 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3537 Correct me if I'm wrong, folks, but the way I understand it
3538 is this: Using DCACHE as initial RAM for Stack, etc, does not
3539 require any physical RAM backing up the cache. The cleverness
3540 is that the cache is being used as a temporary supply of
3541 necessary storage before the SDRAM controller is setup. It's
3542 beyond the scope of this list to expain the details, but you
3543 can see how this works by studying the cache architecture and
3544 operation in the architecture and processor-specific manuals.
3546 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3547 is another option for the system designer to use as an
3548 initial stack/ram area prior to SDRAM being available. Either
3549 option should work for you. Using CS 4 should be fine if your
3550 board designers haven't used it for something that would
3551 cause you grief during the initial boot! It is frequently not
3554 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3555 with your processor/board/system design. The default value
3556 you will find in any recent u-boot distribution in
3557 walnut.h should work for you. I'd set it to a value larger
3558 than your SDRAM module. If you have a 64MB SDRAM module, set
3559 it above 400_0000. Just make sure your board has no resources
3560 that are supposed to respond to that address! That code in
3561 start.S has been around a while and should work as is when
3562 you get the config right.
3567 It is essential to remember this, since it has some impact on the C
3568 code for the initialization procedures:
3570 * Initialized global data (data segment) is read-only. Do not attempt
3573 * Do not use any unitialized global data (or implicitely initialized
3574 as zero data - BSS segment) at all - this is undefined, initiali-
3575 zation is performed later (when relocating to RAM).
3577 * Stack space is very limited. Avoid big data buffers or things like
3580 Having only the stack as writable memory limits means we cannot use
3581 normal global data to share information beween the code. But it
3582 turned out that the implementation of U-Boot can be greatly
3583 simplified by making a global data structure (gd_t) available to all
3584 functions. We could pass a pointer to this data as argument to _all_
3585 functions, but this would bloat the code. Instead we use a feature of
3586 the GCC compiler (Global Register Variables) to share the data: we
3587 place a pointer (gd) to the global data into a register which we
3588 reserve for this purpose.
3590 When choosing a register for such a purpose we are restricted by the
3591 relevant (E)ABI specifications for the current architecture, and by
3592 GCC's implementation.
3594 For PowerPC, the following registers have specific use:
3596 R2: reserved for system use
3597 R3-R4: parameter passing and return values
3598 R5-R10: parameter passing
3599 R13: small data area pointer
3603 (U-Boot also uses R14 as internal GOT pointer.)
3605 ==> U-Boot will use R2 to hold a pointer to the global data
3607 Note: on PPC, we could use a static initializer (since the
3608 address of the global data structure is known at compile time),
3609 but it turned out that reserving a register results in somewhat
3610 smaller code - although the code savings are not that big (on
3611 average for all boards 752 bytes for the whole U-Boot image,
3612 624 text + 127 data).
3614 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3615 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3617 ==> U-Boot will use P5 to hold a pointer to the global data
3619 On ARM, the following registers are used:
3621 R0: function argument word/integer result
3622 R1-R3: function argument word
3624 R10: stack limit (used only if stack checking if enabled)
3625 R11: argument (frame) pointer
3626 R12: temporary workspace
3629 R15: program counter
3631 ==> U-Boot will use R8 to hold a pointer to the global data
3633 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3634 or current versions of GCC may "optimize" the code too much.
3639 U-Boot runs in system state and uses physical addresses, i.e. the
3640 MMU is not used either for address mapping nor for memory protection.
3642 The available memory is mapped to fixed addresses using the memory
3643 controller. In this process, a contiguous block is formed for each
3644 memory type (Flash, SDRAM, SRAM), even when it consists of several
3645 physical memory banks.
3647 U-Boot is installed in the first 128 kB of the first Flash bank (on
3648 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3649 booting and sizing and initializing DRAM, the code relocates itself
3650 to the upper end of DRAM. Immediately below the U-Boot code some
3651 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3652 configuration setting]. Below that, a structure with global Board
3653 Info data is placed, followed by the stack (growing downward).
3655 Additionally, some exception handler code is copied to the low 8 kB
3656 of DRAM (0x00000000 ... 0x00001FFF).
3658 So a typical memory configuration with 16 MB of DRAM could look like
3661 0x0000 0000 Exception Vector code
3664 0x0000 2000 Free for Application Use
3670 0x00FB FF20 Monitor Stack (Growing downward)
3671 0x00FB FFAC Board Info Data and permanent copy of global data
3672 0x00FC 0000 Malloc Arena
3675 0x00FE 0000 RAM Copy of Monitor Code
3676 ... eventually: LCD or video framebuffer
3677 ... eventually: pRAM (Protected RAM - unchanged by reset)
3678 0x00FF FFFF [End of RAM]
3681 System Initialization:
3682 ----------------------
3684 In the reset configuration, U-Boot starts at the reset entry point
3685 (on most PowerPC systens at address 0x00000100). Because of the reset
3686 configuration for CS0# this is a mirror of the onboard Flash memory.
3687 To be able to re-map memory U-Boot then jumps to its link address.
3688 To be able to implement the initialization code in C, a (small!)
3689 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3690 which provide such a feature like MPC8xx or MPC8260), or in a locked
3691 part of the data cache. After that, U-Boot initializes the CPU core,
3692 the caches and the SIU.
3694 Next, all (potentially) available memory banks are mapped using a
3695 preliminary mapping. For example, we put them on 512 MB boundaries
3696 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3697 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3698 programmed for SDRAM access. Using the temporary configuration, a
3699 simple memory test is run that determines the size of the SDRAM
3702 When there is more than one SDRAM bank, and the banks are of
3703 different size, the largest is mapped first. For equal size, the first
3704 bank (CS2#) is mapped first. The first mapping is always for address
3705 0x00000000, with any additional banks following immediately to create
3706 contiguous memory starting from 0.
3708 Then, the monitor installs itself at the upper end of the SDRAM area
3709 and allocates memory for use by malloc() and for the global Board
3710 Info data; also, the exception vector code is copied to the low RAM
3711 pages, and the final stack is set up.
3713 Only after this relocation will you have a "normal" C environment;
3714 until that you are restricted in several ways, mostly because you are
3715 running from ROM, and because the code will have to be relocated to a
3719 U-Boot Porting Guide:
3720 ----------------------
3722 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3726 int main (int argc, char *argv[])
3728 sighandler_t no_more_time;
3730 signal (SIGALRM, no_more_time);
3731 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3733 if (available_money > available_manpower) {
3734 pay consultant to port U-Boot;
3738 Download latest U-Boot source;
3740 Subscribe to u-boot-users mailing list;
3743 email ("Hi, I am new to U-Boot, how do I get started?");
3747 Read the README file in the top level directory;
3748 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3749 Read the source, Luke;
3752 if (available_money > toLocalCurrency ($2500)) {
3755 Add a lot of aggravation and time;
3758 Create your own board support subdirectory;
3760 Create your own board config file;
3764 Add / modify source code;
3768 email ("Hi, I am having problems...");
3770 Send patch file to Wolfgang;
3775 void no_more_time (int sig)
3784 All contributions to U-Boot should conform to the Linux kernel
3785 coding style; see the file "Documentation/CodingStyle" and the script
3786 "scripts/Lindent" in your Linux kernel source directory. In sources
3787 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3788 spaces before parameters to function calls) is actually used.
3790 Source files originating from a different project (for example the
3791 MTD subsystem) are generally exempt from these guidelines and are not
3792 reformated to ease subsequent migration to newer versions of those
3795 Please note that U-Boot is implemented in C (and to some small parts in
3796 Assembler); no C++ is used, so please do not use C++ style comments (//)
3799 Please also stick to the following formatting rules:
3800 - remove any trailing white space
3801 - use TAB characters for indentation, not spaces
3802 - make sure NOT to use DOS '\r\n' line feeds
3803 - do not add more than 2 empty lines to source files
3804 - do not add trailing empty lines to source files
3806 Submissions which do not conform to the standards may be returned
3807 with a request to reformat the changes.
3813 Since the number of patches for U-Boot is growing, we need to
3814 establish some rules. Submissions which do not conform to these rules
3815 may be rejected, even when they contain important and valuable stuff.
3817 Patches shall be sent to the u-boot-users mailing list.
3819 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3821 When you send a patch, please include the following information with
3824 * For bug fixes: a description of the bug and how your patch fixes
3825 this bug. Please try to include a way of demonstrating that the
3826 patch actually fixes something.
3828 * For new features: a description of the feature and your
3831 * A CHANGELOG entry as plaintext (separate from the patch)
3833 * For major contributions, your entry to the CREDITS file
3835 * When you add support for a new board, don't forget to add this
3836 board to the MAKEALL script, too.
3838 * If your patch adds new configuration options, don't forget to
3839 document these in the README file.
3841 * The patch itself. If you are using git (which is *strongly*
3842 recommended) you can easily generate the patch using the
3843 "git-format-patch". If you then use "git-send-email" to send it to
3844 the U-Boot mailing list, you will avoid most of the common problems
3845 with some other mail clients.
3847 If you cannot use git, use "diff -purN OLD NEW". If your version of
3848 diff does not support these options, then get the latest version of
3851 The current directory when running this command shall be the parent
3852 directory of the U-Boot source tree (i. e. please make sure that
3853 your patch includes sufficient directory information for the
3856 We prefer patches as plain text. MIME attachments are discouraged,
3857 and compressed attachments must not be used.
3859 * If one logical set of modifications affects or creates several
3860 files, all these changes shall be submitted in a SINGLE patch file.
3862 * Changesets that contain different, unrelated modifications shall be
3863 submitted as SEPARATE patches, one patch per changeset.
3868 * Before sending the patch, run the MAKEALL script on your patched
3869 source tree and make sure that no errors or warnings are reported
3870 for any of the boards.
3872 * Keep your modifications to the necessary minimum: A patch
3873 containing several unrelated changes or arbitrary reformats will be
3874 returned with a request to re-formatting / split it.
3876 * If you modify existing code, make sure that your new code does not
3877 add to the memory footprint of the code ;-) Small is beautiful!
3878 When adding new features, these should compile conditionally only
3879 (using #ifdef), and the resulting code with the new feature
3880 disabled must not need more memory than the old code without your
3883 * Remember that there is a size limit of 40 kB per message on the
3884 u-boot-users mailing list. Bigger patches will be moderated. If
3885 they are reasonable and not bigger than 100 kB, they will be
3886 acknowledged. Even bigger patches should be avoided.
projects / platform / kernel / u-boot.git / blob