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. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 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 - leon2 Files specific to Gaisler LEON2 SPARC CPU
157 - leon3 Files specific to Gaisler LEON3 SPARC CPU
158 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
159 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
160 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
161 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
162 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
163 - mips Files specific to MIPS CPUs
164 - mpc5xx Files specific to Freescale MPC5xx CPUs
165 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
166 - mpc8xx Files specific to Freescale MPC8xx CPUs
167 - mpc8220 Files specific to Freescale MPC8220 CPUs
168 - mpc824x Files specific to Freescale MPC824x CPUs
169 - mpc8260 Files specific to Freescale MPC8260 CPUs
170 - mpc85xx Files specific to Freescale MPC85xx CPUs
171 - nios Files specific to Altera NIOS CPUs
172 - nios2 Files specific to Altera Nios-II CPUs
173 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
174 - pxa Files specific to Intel XScale PXA CPUs
175 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
176 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
177 - disk Code for disk drive partition handling
178 - doc Documentation (don't expect too much)
179 - drivers Commonly used device drivers
180 - dtt Digital Thermometer and Thermostat drivers
181 - examples Example code for standalone applications, etc.
182 - include Header Files
183 - lib_arm Files generic to ARM architecture
184 - lib_avr32 Files generic to AVR32 architecture
185 - lib_generic Files generic to all architectures
186 - lib_i386 Files generic to i386 architecture
187 - lib_m68k Files generic to m68k architecture
188 - lib_mips Files generic to MIPS architecture
189 - lib_nios Files generic to NIOS architecture
190 - lib_ppc Files generic to PowerPC architecture
191 - lib_sparc Files generic to SPARC architecture
192 - libfdt Library files to support flattened device trees
193 - net Networking code
194 - post Power On Self Test
195 - rtc Real Time Clock drivers
196 - tools Tools to build S-Record or U-Boot images, etc.
198 Software Configuration:
199 =======================
201 Configuration is usually done using C preprocessor defines; the
202 rationale behind that is to avoid dead code whenever possible.
204 There are two classes of configuration variables:
206 * Configuration _OPTIONS_:
207 These are selectable by the user and have names beginning with
210 * Configuration _SETTINGS_:
211 These depend on the hardware etc. and should not be meddled with if
212 you don't know what you're doing; they have names beginning with
215 Later we will add a configuration tool - probably similar to or even
216 identical to what's used for the Linux kernel. Right now, we have to
217 do the configuration by hand, which means creating some symbolic
218 links and editing some configuration files. We use the TQM8xxL boards
222 Selection of Processor Architecture and Board Type:
223 ---------------------------------------------------
225 For all supported boards there are ready-to-use default
226 configurations available; just type "make <board_name>_config".
228 Example: For a TQM823L module type:
233 For the Cogent platform, you need to specify the CPU type as well;
234 e.g. "make cogent_mpc8xx_config". And also configure the cogent
235 directory according to the instructions in cogent/README.
238 Configuration Options:
239 ----------------------
241 Configuration depends on the combination of board and CPU type; all
242 such information is kept in a configuration file
243 "include/configs/<board_name>.h".
245 Example: For a TQM823L module, all configuration settings are in
246 "include/configs/TQM823L.h".
249 Many of the options are named exactly as the corresponding Linux
250 kernel configuration options. The intention is to make it easier to
251 build a config tool - later.
254 The following options need to be configured:
256 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
258 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
260 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
261 Define exactly one, e.g. CONFIG_ATSTK1002
263 - CPU Module Type: (if CONFIG_COGENT is defined)
264 Define exactly one of
266 --- FIXME --- not tested yet:
267 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
268 CONFIG_CMA287_23, CONFIG_CMA287_50
270 - Motherboard Type: (if CONFIG_COGENT is defined)
271 Define exactly one of
272 CONFIG_CMA101, CONFIG_CMA102
274 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
275 Define one or more of
278 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
279 Define one or more of
280 CONFIG_LCD_HEARTBEAT - update a character position on
281 the LCD display every second with
284 - Board flavour: (if CONFIG_MPC8260ADS is defined)
287 CFG_8260ADS - original MPC8260ADS
288 CFG_8266ADS - MPC8266ADS
289 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
290 CFG_8272ADS - MPC8272ADS
292 - MPC824X Family Member (if CONFIG_MPC824X is defined)
293 Define exactly one of
294 CONFIG_MPC8240, CONFIG_MPC8245
296 - 8xx CPU Options: (if using an MPC8xx CPU)
297 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
298 get_gclk_freq() cannot work
299 e.g. if there is no 32KHz
300 reference PIT/RTC clock
301 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
304 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
307 CONFIG_8xx_CPUCLK_DEFAULT
308 See doc/README.MPC866
312 Define this to measure the actual CPU clock instead
313 of relying on the correctness of the configured
314 values. Mostly useful for board bringup to make sure
315 the PLL is locked at the intended frequency. Note
316 that this requires a (stable) reference clock (32 kHz
317 RTC clock or CFG_8XX_XIN)
319 - Intel Monahans options:
320 CFG_MONAHANS_RUN_MODE_OSC_RATIO
322 Defines the Monahans run mode to oscillator
323 ratio. Valid values are 8, 16, 24, 31. The core
324 frequency is this value multiplied by 13 MHz.
326 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
328 Defines the Monahans turbo mode to oscillator
329 ratio. Valid values are 1 (default if undefined) and
330 2. The core frequency as calculated above is multiplied
333 - Linux Kernel Interface:
336 U-Boot stores all clock information in Hz
337 internally. For binary compatibility with older Linux
338 kernels (which expect the clocks passed in the
339 bd_info data to be in MHz) the environment variable
340 "clocks_in_mhz" can be defined so that U-Boot
341 converts clock data to MHZ before passing it to the
343 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
344 "clocks_in_mhz=1" is automatically included in the
347 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
349 When transferring memsize parameter to linux, some versions
350 expect it to be in bytes, others in MB.
351 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
355 New kernel versions are expecting firmware settings to be
356 passed using flattened device trees (based on open firmware
360 * New libfdt-based support
361 * Adds the "fdt" command
362 * The bootm command automatically updates the fdt
364 OF_CPU - The proper name of the cpus node.
365 OF_SOC - The proper name of the soc node.
366 OF_TBCLK - The timebase frequency.
367 OF_STDOUT_PATH - The path to the console device
369 boards with QUICC Engines require OF_QE to set UCC MAC
372 CONFIG_OF_BOARD_SETUP
374 Board code has addition modification that it wants to make
375 to the flat device tree before handing it off to the kernel
379 This define fills in the correct boot CPU in the boot
380 param header, the default value is zero if undefined.
385 Define this if you want support for Amba PrimeCell PL010 UARTs.
389 Define this if you want support for Amba PrimeCell PL011 UARTs.
393 If you have Amba PrimeCell PL011 UARTs, set this variable to
394 the clock speed of the UARTs.
398 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
399 define this to a list of base addresses for each (supported)
400 port. See e.g. include/configs/versatile.h
404 Depending on board, define exactly one serial port
405 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
406 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
407 console by defining CONFIG_8xx_CONS_NONE
409 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
410 port routines must be defined elsewhere
411 (i.e. serial_init(), serial_getc(), ...)
414 Enables console device for a color framebuffer. Needs following
415 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
416 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
418 VIDEO_HW_RECTFILL graphic chip supports
421 VIDEO_HW_BITBLT graphic chip supports
422 bit-blit (cf. smiLynxEM)
423 VIDEO_VISIBLE_COLS visible pixel columns
425 VIDEO_VISIBLE_ROWS visible pixel rows
426 VIDEO_PIXEL_SIZE bytes per pixel
427 VIDEO_DATA_FORMAT graphic data format
428 (0-5, cf. cfb_console.c)
429 VIDEO_FB_ADRS framebuffer address
430 VIDEO_KBD_INIT_FCT keyboard int fct
431 (i.e. i8042_kbd_init())
432 VIDEO_TSTC_FCT test char fct
434 VIDEO_GETC_FCT get char fct
436 CONFIG_CONSOLE_CURSOR cursor drawing on/off
437 (requires blink timer
439 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
440 CONFIG_CONSOLE_TIME display time/date info in
442 (requires CONFIG_CMD_DATE)
443 CONFIG_VIDEO_LOGO display Linux logo in
445 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
446 linux_logo.h for logo.
447 Requires CONFIG_VIDEO_LOGO
448 CONFIG_CONSOLE_EXTRA_INFO
449 additional board info beside
452 When CONFIG_CFB_CONSOLE is defined, video console is
453 default i/o. Serial console can be forced with
454 environment 'console=serial'.
456 When CONFIG_SILENT_CONSOLE is defined, all console
457 messages (by U-Boot and Linux!) can be silenced with
458 the "silent" environment variable. See
459 doc/README.silent for more information.
462 CONFIG_BAUDRATE - in bps
463 Select one of the baudrates listed in
464 CFG_BAUDRATE_TABLE, see below.
465 CFG_BRGCLK_PRESCALE, baudrate prescale
467 - Interrupt driven serial port input:
468 CONFIG_SERIAL_SOFTWARE_FIFO
471 Use an interrupt handler for receiving data on the
472 serial port. It also enables using hardware handshake
473 (RTS/CTS) and UART's built-in FIFO. Set the number of
474 bytes the interrupt driven input buffer should have.
476 Leave undefined to disable this feature, including
477 disable the buffer and hardware handshake.
479 - Console UART Number:
483 If defined internal UART1 (and not UART0) is used
484 as default U-Boot console.
486 - Boot Delay: CONFIG_BOOTDELAY - in seconds
487 Delay before automatically booting the default image;
488 set to -1 to disable autoboot.
490 See doc/README.autoboot for these options that
491 work with CONFIG_BOOTDELAY. None are required.
492 CONFIG_BOOT_RETRY_TIME
493 CONFIG_BOOT_RETRY_MIN
494 CONFIG_AUTOBOOT_KEYED
495 CONFIG_AUTOBOOT_PROMPT
496 CONFIG_AUTOBOOT_DELAY_STR
497 CONFIG_AUTOBOOT_STOP_STR
498 CONFIG_AUTOBOOT_DELAY_STR2
499 CONFIG_AUTOBOOT_STOP_STR2
500 CONFIG_ZERO_BOOTDELAY_CHECK
501 CONFIG_RESET_TO_RETRY
505 Only needed when CONFIG_BOOTDELAY is enabled;
506 define a command string that is automatically executed
507 when no character is read on the console interface
508 within "Boot Delay" after reset.
511 This can be used to pass arguments to the bootm
512 command. The value of CONFIG_BOOTARGS goes into the
513 environment value "bootargs".
515 CONFIG_RAMBOOT and CONFIG_NFSBOOT
516 The value of these goes into the environment as
517 "ramboot" and "nfsboot" respectively, and can be used
518 as a convenience, when switching between booting from
524 When this option is #defined, the existence of the
525 environment variable "preboot" will be checked
526 immediately before starting the CONFIG_BOOTDELAY
527 countdown and/or running the auto-boot command resp.
528 entering interactive mode.
530 This feature is especially useful when "preboot" is
531 automatically generated or modified. For an example
532 see the LWMON board specific code: here "preboot" is
533 modified when the user holds down a certain
534 combination of keys on the (special) keyboard when
537 - Serial Download Echo Mode:
539 If defined to 1, all characters received during a
540 serial download (using the "loads" command) are
541 echoed back. This might be needed by some terminal
542 emulations (like "cu"), but may as well just take
543 time on others. This setting #define's the initial
544 value of the "loads_echo" environment variable.
546 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
548 Select one of the baudrates listed in
549 CFG_BAUDRATE_TABLE, see below.
552 Monitor commands can be included or excluded
553 from the build by using the #include files
554 "config_cmd_all.h" and #undef'ing unwanted
555 commands, or using "config_cmd_default.h"
556 and augmenting with additional #define's
559 The default command configuration includes all commands
560 except those marked below with a "*".
562 CONFIG_CMD_ASKENV * ask for env variable
563 CONFIG_CMD_AUTOSCRIPT Autoscript Support
564 CONFIG_CMD_BDI bdinfo
565 CONFIG_CMD_BEDBUG * Include BedBug Debugger
566 CONFIG_CMD_BMP * BMP support
567 CONFIG_CMD_BSP * Board specific commands
568 CONFIG_CMD_BOOTD bootd
569 CONFIG_CMD_CACHE * icache, dcache
570 CONFIG_CMD_CONSOLE coninfo
571 CONFIG_CMD_DATE * support for RTC, date/time...
572 CONFIG_CMD_DHCP * DHCP support
573 CONFIG_CMD_DIAG * Diagnostics
574 CONFIG_CMD_DOC * Disk-On-Chip Support
575 CONFIG_CMD_DTT * Digital Therm and Thermostat
576 CONFIG_CMD_ECHO echo arguments
577 CONFIG_CMD_EEPROM * EEPROM read/write support
578 CONFIG_CMD_ELF * bootelf, bootvx
579 CONFIG_CMD_ENV saveenv
580 CONFIG_CMD_FDC * Floppy Disk Support
581 CONFIG_CMD_FAT * FAT partition support
582 CONFIG_CMD_FDOS * Dos diskette Support
583 CONFIG_CMD_FLASH flinfo, erase, protect
584 CONFIG_CMD_FPGA FPGA device initialization support
585 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
586 CONFIG_CMD_I2C * I2C serial bus support
587 CONFIG_CMD_IDE * IDE harddisk support
588 CONFIG_CMD_IMI iminfo
589 CONFIG_CMD_IMLS List all found images
590 CONFIG_CMD_IMMAP * IMMR dump support
591 CONFIG_CMD_IRQ * irqinfo
592 CONFIG_CMD_ITEST Integer/string test of 2 values
593 CONFIG_CMD_JFFS2 * JFFS2 Support
594 CONFIG_CMD_KGDB * kgdb
595 CONFIG_CMD_LOADB loadb
596 CONFIG_CMD_LOADS loads
597 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
599 CONFIG_CMD_MISC Misc functions like sleep etc
600 CONFIG_CMD_MMC * MMC memory mapped support
601 CONFIG_CMD_MII * MII utility commands
602 CONFIG_CMD_NAND * NAND support
603 CONFIG_CMD_NET bootp, tftpboot, rarpboot
604 CONFIG_CMD_PCI * pciinfo
605 CONFIG_CMD_PCMCIA * PCMCIA support
606 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
608 CONFIG_CMD_PORTIO * Port I/O
609 CONFIG_CMD_REGINFO * Register dump
610 CONFIG_CMD_RUN run command in env variable
611 CONFIG_CMD_SAVES * save S record dump
612 CONFIG_CMD_SCSI * SCSI Support
613 CONFIG_CMD_SDRAM * print SDRAM configuration information
614 (requires CONFIG_CMD_I2C)
615 CONFIG_CMD_SETGETDCR Support for DCR Register access
617 CONFIG_CMD_SPI * SPI serial bus support
618 CONFIG_CMD_USB * USB support
619 CONFIG_CMD_VFD * VFD support (TRAB)
620 CONFIG_CMD_CDP * Cisco Discover Protocol support
621 CONFIG_CMD_FSL * Microblaze FSL support
624 EXAMPLE: If you want all functions except of network
625 support you can write:
627 #include "config_cmd_all.h"
628 #undef CONFIG_CMD_NET
631 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
633 Note: Don't enable the "icache" and "dcache" commands
634 (configuration option CONFIG_CMD_CACHE) unless you know
635 what you (and your U-Boot users) are doing. Data
636 cache cannot be enabled on systems like the 8xx or
637 8260 (where accesses to the IMMR region must be
638 uncached), and it cannot be disabled on all other
639 systems where we (mis-) use the data cache to hold an
640 initial stack and some data.
643 XXX - this list needs to get updated!
647 If this variable is defined, it enables watchdog
648 support. There must be support in the platform specific
649 code for a watchdog. For the 8xx and 8260 CPUs, the
650 SIU Watchdog feature is enabled in the SYPCR
654 CONFIG_VERSION_VARIABLE
655 If this variable is defined, an environment variable
656 named "ver" is created by U-Boot showing the U-Boot
657 version as printed by the "version" command.
658 This variable is readonly.
662 When CONFIG_CMD_DATE is selected, the type of the RTC
663 has to be selected, too. Define exactly one of the
666 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
667 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
668 CONFIG_RTC_MC13783 - use MC13783 RTC
669 CONFIG_RTC_MC146818 - use MC146818 RTC
670 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
671 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
672 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
673 CONFIG_RTC_DS164x - use Dallas DS164x RTC
674 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
675 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
676 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
678 Note that if the RTC uses I2C, then the I2C interface
679 must also be configured. See I2C Support, below.
683 When CONFIG_TIMESTAMP is selected, the timestamp
684 (date and time) of an image is printed by image
685 commands like bootm or iminfo. This option is
686 automatically enabled when you select CONFIG_CMD_DATE .
689 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
690 and/or CONFIG_ISO_PARTITION
692 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
693 CONFIG_CMD_SCSI) you must configure support for at
694 least one partition type as well.
697 CONFIG_IDE_RESET_ROUTINE - this is defined in several
698 board configurations files but used nowhere!
700 CONFIG_IDE_RESET - is this is defined, IDE Reset will
701 be performed by calling the function
702 ide_set_reset(int reset)
703 which has to be defined in a board specific file
708 Set this to enable ATAPI support.
713 Set this to enable support for disks larger than 137GB
714 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
715 Whithout these , LBA48 support uses 32bit variables and will 'only'
716 support disks up to 2.1TB.
719 When enabled, makes the IDE subsystem use 64bit sector addresses.
723 At the moment only there is only support for the
724 SYM53C8XX SCSI controller; define
725 CONFIG_SCSI_SYM53C8XX to enable it.
727 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
728 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
729 CFG_SCSI_MAX_LUN] can be adjusted to define the
730 maximum numbers of LUNs, SCSI ID's and target
732 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
734 - NETWORK Support (PCI):
736 Support for Intel 8254x gigabit chips.
738 CONFIG_E1000_FALLBACK_MAC
739 default MAC for empty EEPROM after production.
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)
783 CONFIG_DRIVER_SMC911X
784 Support for SMSC's LAN911x and LAN921x chips
786 CONFIG_DRIVER_SMC911X_BASE
787 Define this to hold the physical address
788 of the device (I/O space)
790 CONFIG_DRIVER_SMC911X_32_BIT
791 Define this if data bus is 32 bits
793 CONFIG_DRIVER_SMC911X_16_BIT
794 Define this if data bus is 16 bits. If your processor
795 automatically converts one 32 bit word to two 16 bit
796 words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
799 At the moment only the UHCI host controller is
800 supported (PIP405, MIP405, MPC5200); define
801 CONFIG_USB_UHCI to enable it.
802 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
803 and define CONFIG_USB_STORAGE to enable the USB
806 Supported are USB Keyboards and USB Floppy drives
808 MPC5200 USB requires additional defines:
810 for 528 MHz Clock: 0x0001bbbb
812 for differential drivers: 0x00001000
813 for single ended drivers: 0x00005000
815 May be defined to allow interrupt polling
816 instead of using asynchronous interrupts
819 Define the below if you wish to use the USB console.
820 Once firmware is rebuilt from a serial console issue the
821 command "setenv stdin usbtty; setenv stdout usbtty" and
822 attach your USB cable. The Unix command "dmesg" should print
823 it has found a new device. The environment variable usbtty
824 can be set to gserial or cdc_acm to enable your device to
825 appear to a USB host as a Linux gserial device or a
826 Common Device Class Abstract Control Model serial device.
827 If you select usbtty = gserial you should be able to enumerate
829 # modprobe usbserial vendor=0xVendorID product=0xProductID
830 else if using cdc_acm, simply setting the environment
831 variable usbtty to be cdc_acm should suffice. The following
832 might be defined in YourBoardName.h
835 Define this to build a UDC device
838 Define this to have a tty type of device available to
839 talk to the UDC device
841 CFG_CONSOLE_IS_IN_ENV
842 Define this if you want stdin, stdout &/or stderr to
846 CFG_USB_EXTC_CLK 0xBLAH
847 Derive USB clock from external clock "blah"
848 - CFG_USB_EXTC_CLK 0x02
850 CFG_USB_BRG_CLK 0xBLAH
851 Derive USB clock from brgclk
852 - CFG_USB_BRG_CLK 0x04
854 If you have a USB-IF assigned VendorID then you may wish to
855 define your own vendor specific values either in BoardName.h
856 or directly in usbd_vendor_info.h. If you don't define
857 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
858 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
859 should pretend to be a Linux device to it's target host.
861 CONFIG_USBD_MANUFACTURER
862 Define this string as the name of your company for
863 - CONFIG_USBD_MANUFACTURER "my company"
865 CONFIG_USBD_PRODUCT_NAME
866 Define this string as the name of your product
867 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
870 Define this as your assigned Vendor ID from the USB
871 Implementors Forum. This *must* be a genuine Vendor ID
872 to avoid polluting the USB namespace.
873 - CONFIG_USBD_VENDORID 0xFFFF
875 CONFIG_USBD_PRODUCTID
876 Define this as the unique Product ID
878 - CONFIG_USBD_PRODUCTID 0xFFFF
882 The MMC controller on the Intel PXA is supported. To
883 enable this define CONFIG_MMC. The MMC can be
884 accessed from the boot prompt by mapping the device
885 to physical memory similar to flash. Command line is
886 enabled with CONFIG_CMD_MMC. The MMC driver also works with
887 the FAT fs. This is enabled with CONFIG_CMD_FAT.
889 - Journaling Flash filesystem support:
890 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
891 CONFIG_JFFS2_NAND_DEV
892 Define these for a default partition on a NAND device
894 CFG_JFFS2_FIRST_SECTOR,
895 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
896 Define these for a default partition on a NOR device
899 Define this to create an own partition. You have to provide a
900 function struct part_info* jffs2_part_info(int part_num)
902 If you define only one JFFS2 partition you may also want to
903 #define CFG_JFFS_SINGLE_PART 1
904 to disable the command chpart. This is the default when you
905 have not defined a custom partition
910 Define this to enable standard (PC-Style) keyboard
914 Standard PC keyboard driver with US (is default) and
915 GERMAN key layout (switch via environment 'keymap=de') support.
916 Export function i8042_kbd_init, i8042_tstc and i8042_getc
917 for cfb_console. Supports cursor blinking.
922 Define this to enable video support (for output to
927 Enable Chips & Technologies 69000 Video chip
929 CONFIG_VIDEO_SMI_LYNXEM
930 Enable Silicon Motion SMI 712/710/810 Video chip. The
931 video output is selected via environment 'videoout'
932 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
935 For the CT69000 and SMI_LYNXEM drivers, videomode is
936 selected via environment 'videomode'. Two different ways
938 - "videomode=num" 'num' is a standard LiLo mode numbers.
939 Following standard modes are supported (* is default):
941 Colors 640x480 800x600 1024x768 1152x864 1280x1024
942 -------------+---------------------------------------------
943 8 bits | 0x301* 0x303 0x305 0x161 0x307
944 15 bits | 0x310 0x313 0x316 0x162 0x319
945 16 bits | 0x311 0x314 0x317 0x163 0x31A
946 24 bits | 0x312 0x315 0x318 ? 0x31B
947 -------------+---------------------------------------------
948 (i.e. setenv videomode 317; saveenv; reset;)
950 - "videomode=bootargs" all the video parameters are parsed
951 from the bootargs. (See drivers/video/videomodes.c)
954 CONFIG_VIDEO_SED13806
955 Enable Epson SED13806 driver. This driver supports 8bpp
956 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
957 or CONFIG_VIDEO_SED13806_16BPP
962 Define this to enable a custom keyboard support.
963 This simply calls drv_keyboard_init() which must be
964 defined in your board-specific files.
965 The only board using this so far is RBC823.
967 - LCD Support: CONFIG_LCD
969 Define this to enable LCD support (for output to LCD
970 display); also select one of the supported displays
971 by defining one of these:
975 HITACHI TX09D70VM1CCA, 3.5", 240x320.
977 CONFIG_NEC_NL6448AC33:
979 NEC NL6448AC33-18. Active, color, single scan.
981 CONFIG_NEC_NL6448BC20
983 NEC NL6448BC20-08. 6.5", 640x480.
984 Active, color, single scan.
986 CONFIG_NEC_NL6448BC33_54
988 NEC NL6448BC33-54. 10.4", 640x480.
989 Active, color, single scan.
993 Sharp 320x240. Active, color, single scan.
994 It isn't 16x9, and I am not sure what it is.
996 CONFIG_SHARP_LQ64D341
998 Sharp LQ64D341 display, 640x480.
999 Active, color, single scan.
1003 HLD1045 display, 640x480.
1004 Active, color, single scan.
1008 Optrex CBL50840-2 NF-FW 99 22 M5
1010 Hitachi LMG6912RPFC-00T
1014 320x240. Black & white.
1016 Normally display is black on white background; define
1017 CFG_WHITE_ON_BLACK to get it inverted.
1019 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1021 If this option is set, the environment is checked for
1022 a variable "splashimage". If found, the usual display
1023 of logo, copyright and system information on the LCD
1024 is suppressed and the BMP image at the address
1025 specified in "splashimage" is loaded instead. The
1026 console is redirected to the "nulldev", too. This
1027 allows for a "silent" boot where a splash screen is
1028 loaded very quickly after power-on.
1030 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1032 If this option is set, additionally to standard BMP
1033 images, gzipped BMP images can be displayed via the
1034 splashscreen support or the bmp command.
1036 - Compression support:
1039 If this option is set, support for bzip2 compressed
1040 images is included. If not, only uncompressed and gzip
1041 compressed images are supported.
1043 NOTE: the bzip2 algorithm requires a lot of RAM, so
1044 the malloc area (as defined by CFG_MALLOC_LEN) should
1050 The address of PHY on MII bus.
1052 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1054 The clock frequency of the MII bus
1058 If this option is set, support for speed/duplex
1059 detection of gigabit PHY is included.
1061 CONFIG_PHY_RESET_DELAY
1063 Some PHY like Intel LXT971A need extra delay after
1064 reset before any MII register access is possible.
1065 For such PHY, set this option to the usec delay
1066 required. (minimum 300usec for LXT971A)
1068 CONFIG_PHY_CMD_DELAY (ppc4xx)
1070 Some PHY like Intel LXT971A need extra delay after
1071 command issued before MII status register can be read
1078 Define a default value for Ethernet address to use
1079 for the respective Ethernet interface, in case this
1080 is not determined automatically.
1085 Define a default value for the IP address to use for
1086 the default Ethernet interface, in case this is not
1087 determined through e.g. bootp.
1089 - Server IP address:
1092 Defines a default value for the IP address of a TFTP
1093 server to contact when using the "tftboot" command.
1095 - Multicast TFTP Mode:
1098 Defines whether you want to support multicast TFTP as per
1099 rfc-2090; for example to work with atftp. Lets lots of targets
1100 tftp down the same boot image concurrently. Note: the Ethernet
1101 driver in use must provide a function: mcast() to join/leave a
1104 CONFIG_BOOTP_RANDOM_DELAY
1105 - BOOTP Recovery Mode:
1106 CONFIG_BOOTP_RANDOM_DELAY
1108 If you have many targets in a network that try to
1109 boot using BOOTP, you may want to avoid that all
1110 systems send out BOOTP requests at precisely the same
1111 moment (which would happen for instance at recovery
1112 from a power failure, when all systems will try to
1113 boot, thus flooding the BOOTP server. Defining
1114 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1115 inserted before sending out BOOTP requests. The
1116 following delays are inserted then:
1118 1st BOOTP request: delay 0 ... 1 sec
1119 2nd BOOTP request: delay 0 ... 2 sec
1120 3rd BOOTP request: delay 0 ... 4 sec
1122 BOOTP requests: delay 0 ... 8 sec
1124 - DHCP Advanced Options:
1125 You can fine tune the DHCP functionality by defining
1126 CONFIG_BOOTP_* symbols:
1128 CONFIG_BOOTP_SUBNETMASK
1129 CONFIG_BOOTP_GATEWAY
1130 CONFIG_BOOTP_HOSTNAME
1131 CONFIG_BOOTP_NISDOMAIN
1132 CONFIG_BOOTP_BOOTPATH
1133 CONFIG_BOOTP_BOOTFILESIZE
1136 CONFIG_BOOTP_SEND_HOSTNAME
1137 CONFIG_BOOTP_NTPSERVER
1138 CONFIG_BOOTP_TIMEOFFSET
1139 CONFIG_BOOTP_VENDOREX
1141 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1142 environment variable, not the BOOTP server.
1144 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1145 serverip from a DHCP server, it is possible that more
1146 than one DNS serverip is offered to the client.
1147 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1148 serverip will be stored in the additional environment
1149 variable "dnsip2". The first DNS serverip is always
1150 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1153 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1154 to do a dynamic update of a DNS server. To do this, they
1155 need the hostname of the DHCP requester.
1156 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1157 of the "hostname" environment variable is passed as
1158 option 12 to the DHCP server.
1160 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1162 A 32bit value in microseconds for a delay between
1163 receiving a "DHCP Offer" and sending the "DHCP Request".
1164 This fixes a problem with certain DHCP servers that don't
1165 respond 100% of the time to a "DHCP request". E.g. On an
1166 AT91RM9200 processor running at 180MHz, this delay needed
1167 to be *at least* 15,000 usec before a Windows Server 2003
1168 DHCP server would reply 100% of the time. I recommend at
1169 least 50,000 usec to be safe. The alternative is to hope
1170 that one of the retries will be successful but note that
1171 the DHCP timeout and retry process takes a longer than
1175 CONFIG_CDP_DEVICE_ID
1177 The device id used in CDP trigger frames.
1179 CONFIG_CDP_DEVICE_ID_PREFIX
1181 A two character string which is prefixed to the MAC address
1186 A printf format string which contains the ascii name of
1187 the port. Normally is set to "eth%d" which sets
1188 eth0 for the first Ethernet, eth1 for the second etc.
1190 CONFIG_CDP_CAPABILITIES
1192 A 32bit integer which indicates the device capabilities;
1193 0x00000010 for a normal host which does not forwards.
1197 An ascii string containing the version of the software.
1201 An ascii string containing the name of the platform.
1205 A 32bit integer sent on the trigger.
1207 CONFIG_CDP_POWER_CONSUMPTION
1209 A 16bit integer containing the power consumption of the
1210 device in .1 of milliwatts.
1212 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1214 A byte containing the id of the VLAN.
1216 - Status LED: CONFIG_STATUS_LED
1218 Several configurations allow to display the current
1219 status using a LED. For instance, the LED will blink
1220 fast while running U-Boot code, stop blinking as
1221 soon as a reply to a BOOTP request was received, and
1222 start blinking slow once the Linux kernel is running
1223 (supported by a status LED driver in the Linux
1224 kernel). Defining CONFIG_STATUS_LED enables this
1227 - CAN Support: CONFIG_CAN_DRIVER
1229 Defining CONFIG_CAN_DRIVER enables CAN driver support
1230 on those systems that support this (optional)
1231 feature, like the TQM8xxL modules.
1233 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1235 These enable I2C serial bus commands. Defining either of
1236 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1237 include the appropriate I2C driver for the selected CPU.
1239 This will allow you to use i2c commands at the u-boot
1240 command line (as long as you set CONFIG_CMD_I2C in
1241 CONFIG_COMMANDS) and communicate with i2c based realtime
1242 clock chips. See common/cmd_i2c.c for a description of the
1243 command line interface.
1245 CONFIG_I2C_CMD_TREE is a recommended option that places
1246 all I2C commands under a single 'i2c' root command. The
1247 older 'imm', 'imd', 'iprobe' etc. commands are considered
1248 deprecated and may disappear in the future.
1250 CONFIG_HARD_I2C selects a hardware I2C controller.
1252 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1253 bit-banging) driver instead of CPM or similar hardware
1256 There are several other quantities that must also be
1257 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1259 In both cases you will need to define CFG_I2C_SPEED
1260 to be the frequency (in Hz) at which you wish your i2c bus
1261 to run and CFG_I2C_SLAVE to be the address of this node (ie
1262 the CPU's i2c node address).
1264 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1265 sets the CPU up as a master node and so its address should
1266 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1267 p.16-473). So, set CFG_I2C_SLAVE to 0.
1269 That's all that's required for CONFIG_HARD_I2C.
1271 If you use the software i2c interface (CONFIG_SOFT_I2C)
1272 then the following macros need to be defined (examples are
1273 from include/configs/lwmon.h):
1277 (Optional). Any commands necessary to enable the I2C
1278 controller or configure ports.
1280 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1284 (Only for MPC8260 CPU). The I/O port to use (the code
1285 assumes both bits are on the same port). Valid values
1286 are 0..3 for ports A..D.
1290 The code necessary to make the I2C data line active
1291 (driven). If the data line is open collector, this
1294 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1298 The code necessary to make the I2C data line tri-stated
1299 (inactive). If the data line is open collector, this
1302 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1306 Code that returns TRUE if the I2C data line is high,
1309 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1313 If <bit> is TRUE, sets the I2C data line high. If it
1314 is FALSE, it clears it (low).
1316 eg: #define I2C_SDA(bit) \
1317 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1318 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1322 If <bit> is TRUE, sets the I2C clock line high. If it
1323 is FALSE, it clears it (low).
1325 eg: #define I2C_SCL(bit) \
1326 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1327 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1331 This delay is invoked four times per clock cycle so this
1332 controls the rate of data transfer. The data rate thus
1333 is 1 / (I2C_DELAY * 4). Often defined to be something
1336 #define I2C_DELAY udelay(2)
1340 When a board is reset during an i2c bus transfer
1341 chips might think that the current transfer is still
1342 in progress. On some boards it is possible to access
1343 the i2c SCLK line directly, either by using the
1344 processor pin as a GPIO or by having a second pin
1345 connected to the bus. If this option is defined a
1346 custom i2c_init_board() routine in boards/xxx/board.c
1347 is run early in the boot sequence.
1349 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1351 This option enables configuration of bi_iic_fast[] flags
1352 in u-boot bd_info structure based on u-boot environment
1353 variable "i2cfast". (see also i2cfast)
1355 CONFIG_I2C_MULTI_BUS
1357 This option allows the use of multiple I2C buses, each of which
1358 must have a controller. At any point in time, only one bus is
1359 active. To switch to a different bus, use the 'i2c dev' command.
1360 Note that bus numbering is zero-based.
1364 This option specifies a list of I2C devices that will be skipped
1365 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1366 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1367 pairs. Otherwise, specify a 1D array of device addresses
1370 #undef CONFIG_I2C_MULTI_BUS
1371 #define CFG_I2C_NOPROBES {0x50,0x68}
1373 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1375 #define CONFIG_I2C_MULTI_BUS
1376 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1378 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1382 If defined, then this indicates the I2C bus number for DDR SPD.
1383 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1387 If defined, then this indicates the I2C bus number for the RTC.
1388 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1392 If defined, then this indicates the I2C bus number for the DTT.
1393 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1397 If defined, specifies the I2C address of the DTT device.
1398 If not defined, then U-Boot uses predefined value for
1399 specified DTT device.
1403 Define this option if you want to use Freescale's I2C driver in
1404 drivers/i2c/fsl_i2c.c.
1407 - SPI Support: CONFIG_SPI
1409 Enables SPI driver (so far only tested with
1410 SPI EEPROM, also an instance works with Crystal A/D and
1411 D/As on the SACSng board)
1415 Enables extended (16-bit) SPI EEPROM addressing.
1416 (symmetrical to CONFIG_I2C_X)
1420 Enables a software (bit-bang) SPI driver rather than
1421 using hardware support. This is a general purpose
1422 driver that only requires three general I/O port pins
1423 (two outputs, one input) to function. If this is
1424 defined, the board configuration must define several
1425 SPI configuration items (port pins to use, etc). For
1426 an example, see include/configs/sacsng.h.
1430 Enables a hardware SPI driver for general-purpose reads
1431 and writes. As with CONFIG_SOFT_SPI, the board configuration
1432 must define a list of chip-select function pointers.
1433 Currently supported on some MPC8xxx processors. For an
1434 example, see include/configs/mpc8349emds.h.
1438 Enables the driver for the SPI controllers on i.MX and MXC
1439 SoCs. Currently only i.MX31 is supported.
1441 - FPGA Support: CONFIG_FPGA
1443 Enables FPGA subsystem.
1445 CONFIG_FPGA_<vendor>
1447 Enables support for specific chip vendors.
1450 CONFIG_FPGA_<family>
1452 Enables support for FPGA family.
1453 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1457 Specify the number of FPGA devices to support.
1459 CFG_FPGA_PROG_FEEDBACK
1461 Enable printing of hash marks during FPGA configuration.
1465 Enable checks on FPGA configuration interface busy
1466 status by the configuration function. This option
1467 will require a board or device specific function to
1472 If defined, a function that provides delays in the FPGA
1473 configuration driver.
1475 CFG_FPGA_CHECK_CTRLC
1476 Allow Control-C to interrupt FPGA configuration
1478 CFG_FPGA_CHECK_ERROR
1480 Check for configuration errors during FPGA bitfile
1481 loading. For example, abort during Virtex II
1482 configuration if the INIT_B line goes low (which
1483 indicated a CRC error).
1487 Maximum time to wait for the INIT_B line to deassert
1488 after PROB_B has been deasserted during a Virtex II
1489 FPGA configuration sequence. The default time is 500
1494 Maximum time to wait for BUSY to deassert during
1495 Virtex II FPGA configuration. The default is 5 ms.
1497 CFG_FPGA_WAIT_CONFIG
1499 Time to wait after FPGA configuration. The default is
1502 - Configuration Management:
1505 If defined, this string will be added to the U-Boot
1506 version information (U_BOOT_VERSION)
1508 - Vendor Parameter Protection:
1510 U-Boot considers the values of the environment
1511 variables "serial#" (Board Serial Number) and
1512 "ethaddr" (Ethernet Address) to be parameters that
1513 are set once by the board vendor / manufacturer, and
1514 protects these variables from casual modification by
1515 the user. Once set, these variables are read-only,
1516 and write or delete attempts are rejected. You can
1517 change this behaviour:
1519 If CONFIG_ENV_OVERWRITE is #defined in your config
1520 file, the write protection for vendor parameters is
1521 completely disabled. Anybody can change or delete
1524 Alternatively, if you #define _both_ CONFIG_ETHADDR
1525 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1526 Ethernet address is installed in the environment,
1527 which can be changed exactly ONCE by the user. [The
1528 serial# is unaffected by this, i. e. it remains
1534 Define this variable to enable the reservation of
1535 "protected RAM", i. e. RAM which is not overwritten
1536 by U-Boot. Define CONFIG_PRAM to hold the number of
1537 kB you want to reserve for pRAM. You can overwrite
1538 this default value by defining an environment
1539 variable "pram" to the number of kB you want to
1540 reserve. Note that the board info structure will
1541 still show the full amount of RAM. If pRAM is
1542 reserved, a new environment variable "mem" will
1543 automatically be defined to hold the amount of
1544 remaining RAM in a form that can be passed as boot
1545 argument to Linux, for instance like that:
1547 setenv bootargs ... mem=\${mem}
1550 This way you can tell Linux not to use this memory,
1551 either, which results in a memory region that will
1552 not be affected by reboots.
1554 *WARNING* If your board configuration uses automatic
1555 detection of the RAM size, you must make sure that
1556 this memory test is non-destructive. So far, the
1557 following board configurations are known to be
1560 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1561 HERMES, IP860, RPXlite, LWMON, LANTEC,
1562 PCU_E, FLAGADM, TQM8260
1567 Define this variable to stop the system in case of a
1568 fatal error, so that you have to reset it manually.
1569 This is probably NOT a good idea for an embedded
1570 system where you want the system to reboot
1571 automatically as fast as possible, but it may be
1572 useful during development since you can try to debug
1573 the conditions that lead to the situation.
1575 CONFIG_NET_RETRY_COUNT
1577 This variable defines the number of retries for
1578 network operations like ARP, RARP, TFTP, or BOOTP
1579 before giving up the operation. If not defined, a
1580 default value of 5 is used.
1584 Timeout waiting for an ARP reply in milliseconds.
1586 - Command Interpreter:
1587 CONFIG_AUTO_COMPLETE
1589 Enable auto completion of commands using TAB.
1591 Note that this feature has NOT been implemented yet
1592 for the "hush" shell.
1597 Define this variable to enable the "hush" shell (from
1598 Busybox) as command line interpreter, thus enabling
1599 powerful command line syntax like
1600 if...then...else...fi conditionals or `&&' and '||'
1601 constructs ("shell scripts").
1603 If undefined, you get the old, much simpler behaviour
1604 with a somewhat smaller memory footprint.
1609 This defines the secondary prompt string, which is
1610 printed when the command interpreter needs more input
1611 to complete a command. Usually "> ".
1615 In the current implementation, the local variables
1616 space and global environment variables space are
1617 separated. Local variables are those you define by
1618 simply typing `name=value'. To access a local
1619 variable later on, you have write `$name' or
1620 `${name}'; to execute the contents of a variable
1621 directly type `$name' at the command prompt.
1623 Global environment variables are those you use
1624 setenv/printenv to work with. To run a command stored
1625 in such a variable, you need to use the run command,
1626 and you must not use the '$' sign to access them.
1628 To store commands and special characters in a
1629 variable, please use double quotation marks
1630 surrounding the whole text of the variable, instead
1631 of the backslashes before semicolons and special
1634 - Commandline Editing and History:
1635 CONFIG_CMDLINE_EDITING
1637 Enable editing and History functions for interactive
1638 commandline input operations
1640 - Default Environment:
1641 CONFIG_EXTRA_ENV_SETTINGS
1643 Define this to contain any number of null terminated
1644 strings (variable = value pairs) that will be part of
1645 the default environment compiled into the boot image.
1647 For example, place something like this in your
1648 board's config file:
1650 #define CONFIG_EXTRA_ENV_SETTINGS \
1654 Warning: This method is based on knowledge about the
1655 internal format how the environment is stored by the
1656 U-Boot code. This is NOT an official, exported
1657 interface! Although it is unlikely that this format
1658 will change soon, there is no guarantee either.
1659 You better know what you are doing here.
1661 Note: overly (ab)use of the default environment is
1662 discouraged. Make sure to check other ways to preset
1663 the environment like the autoscript function or the
1666 - DataFlash Support:
1667 CONFIG_HAS_DATAFLASH
1669 Defining this option enables DataFlash features and
1670 allows to read/write in Dataflash via the standard
1673 - SystemACE Support:
1676 Adding this option adds support for Xilinx SystemACE
1677 chips attached via some sort of local bus. The address
1678 of the chip must also be defined in the
1679 CFG_SYSTEMACE_BASE macro. For example:
1681 #define CONFIG_SYSTEMACE
1682 #define CFG_SYSTEMACE_BASE 0xf0000000
1684 When SystemACE support is added, the "ace" device type
1685 becomes available to the fat commands, i.e. fatls.
1687 - TFTP Fixed UDP Port:
1690 If this is defined, the environment variable tftpsrcp
1691 is used to supply the TFTP UDP source port value.
1692 If tftpsrcp isn't defined, the normal pseudo-random port
1693 number generator is used.
1695 Also, the environment variable tftpdstp is used to supply
1696 the TFTP UDP destination port value. If tftpdstp isn't
1697 defined, the normal port 69 is used.
1699 The purpose for tftpsrcp is to allow a TFTP server to
1700 blindly start the TFTP transfer using the pre-configured
1701 target IP address and UDP port. This has the effect of
1702 "punching through" the (Windows XP) firewall, allowing
1703 the remainder of the TFTP transfer to proceed normally.
1704 A better solution is to properly configure the firewall,
1705 but sometimes that is not allowed.
1707 - Show boot progress:
1708 CONFIG_SHOW_BOOT_PROGRESS
1710 Defining this option allows to add some board-
1711 specific code (calling a user-provided function
1712 "show_boot_progress(int)") that enables you to show
1713 the system's boot progress on some display (for
1714 example, some LED's) on your board. At the moment,
1715 the following checkpoints are implemented:
1717 Legacy uImage format:
1720 1 common/cmd_bootm.c before attempting to boot an image
1721 -1 common/cmd_bootm.c Image header has bad magic number
1722 2 common/cmd_bootm.c Image header has correct magic number
1723 -2 common/cmd_bootm.c Image header has bad checksum
1724 3 common/cmd_bootm.c Image header has correct checksum
1725 -3 common/cmd_bootm.c Image data has bad checksum
1726 4 common/cmd_bootm.c Image data has correct checksum
1727 -4 common/cmd_bootm.c Image is for unsupported architecture
1728 5 common/cmd_bootm.c Architecture check OK
1729 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1730 6 common/cmd_bootm.c Image Type check OK
1731 -6 common/cmd_bootm.c gunzip uncompression error
1732 -7 common/cmd_bootm.c Unimplemented compression type
1733 7 common/cmd_bootm.c Uncompression OK
1734 8 common/cmd_bootm.c No uncompress/copy overwrite error
1735 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1737 9 common/image.c Start initial ramdisk verification
1738 -10 common/image.c Ramdisk header has bad magic number
1739 -11 common/image.c Ramdisk header has bad checksum
1740 10 common/image.c Ramdisk header is OK
1741 -12 common/image.c Ramdisk data has bad checksum
1742 11 common/image.c Ramdisk data has correct checksum
1743 12 common/image.c Ramdisk verification complete, start loading
1744 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1745 13 common/image.c Start multifile image verification
1746 14 common/image.c No initial ramdisk, no multifile, continue.
1748 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1750 -30 lib_ppc/board.c Fatal error, hang the system
1751 -31 post/post.c POST test failed, detected by post_output_backlog()
1752 -32 post/post.c POST test failed, detected by post_run_single()
1754 34 common/cmd_doc.c before loading a Image from a DOC device
1755 -35 common/cmd_doc.c Bad usage of "doc" command
1756 35 common/cmd_doc.c correct usage of "doc" command
1757 -36 common/cmd_doc.c No boot device
1758 36 common/cmd_doc.c correct boot device
1759 -37 common/cmd_doc.c Unknown Chip ID on boot device
1760 37 common/cmd_doc.c correct chip ID found, device available
1761 -38 common/cmd_doc.c Read Error on boot device
1762 38 common/cmd_doc.c reading Image header from DOC device OK
1763 -39 common/cmd_doc.c Image header has bad magic number
1764 39 common/cmd_doc.c Image header has correct magic number
1765 -40 common/cmd_doc.c Error reading Image from DOC device
1766 40 common/cmd_doc.c Image header has correct magic number
1767 41 common/cmd_ide.c before loading a Image from a IDE device
1768 -42 common/cmd_ide.c Bad usage of "ide" command
1769 42 common/cmd_ide.c correct usage of "ide" command
1770 -43 common/cmd_ide.c No boot device
1771 43 common/cmd_ide.c boot device found
1772 -44 common/cmd_ide.c Device not available
1773 44 common/cmd_ide.c Device available
1774 -45 common/cmd_ide.c wrong partition selected
1775 45 common/cmd_ide.c partition selected
1776 -46 common/cmd_ide.c Unknown partition table
1777 46 common/cmd_ide.c valid partition table found
1778 -47 common/cmd_ide.c Invalid partition type
1779 47 common/cmd_ide.c correct partition type
1780 -48 common/cmd_ide.c Error reading Image Header on boot device
1781 48 common/cmd_ide.c reading Image Header from IDE device OK
1782 -49 common/cmd_ide.c Image header has bad magic number
1783 49 common/cmd_ide.c Image header has correct magic number
1784 -50 common/cmd_ide.c Image header has bad checksum
1785 50 common/cmd_ide.c Image header has correct checksum
1786 -51 common/cmd_ide.c Error reading Image from IDE device
1787 51 common/cmd_ide.c reading Image from IDE device OK
1788 52 common/cmd_nand.c before loading a Image from a NAND device
1789 -53 common/cmd_nand.c Bad usage of "nand" command
1790 53 common/cmd_nand.c correct usage of "nand" command
1791 -54 common/cmd_nand.c No boot device
1792 54 common/cmd_nand.c boot device found
1793 -55 common/cmd_nand.c Unknown Chip ID on boot device
1794 55 common/cmd_nand.c correct chip ID found, device available
1795 -56 common/cmd_nand.c Error reading Image Header on boot device
1796 56 common/cmd_nand.c reading Image Header from NAND device OK
1797 -57 common/cmd_nand.c Image header has bad magic number
1798 57 common/cmd_nand.c Image header has correct magic number
1799 -58 common/cmd_nand.c Error reading Image from NAND device
1800 58 common/cmd_nand.c reading Image from NAND device OK
1802 -60 common/env_common.c Environment has a bad CRC, using default
1804 64 net/eth.c starting with Ethernet configuration.
1805 -64 net/eth.c no Ethernet found.
1806 65 net/eth.c Ethernet found.
1808 -80 common/cmd_net.c usage wrong
1809 80 common/cmd_net.c before calling NetLoop()
1810 -81 common/cmd_net.c some error in NetLoop() occurred
1811 81 common/cmd_net.c NetLoop() back without error
1812 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1813 82 common/cmd_net.c trying automatic boot
1814 83 common/cmd_net.c running autoscript
1815 -83 common/cmd_net.c some error in automatic boot or autoscript
1816 84 common/cmd_net.c end without errors
1821 100 common/cmd_bootm.c Kernel FIT Image has correct format
1822 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1823 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1824 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1825 102 common/cmd_bootm.c Kernel unit name specified
1826 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1827 103 common/cmd_bootm.c Found configuration node
1828 104 common/cmd_bootm.c Got kernel subimage node offset
1829 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1830 105 common/cmd_bootm.c Kernel subimage hash verification OK
1831 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1832 106 common/cmd_bootm.c Architecture check OK
1833 -106 common/cmd_bootm.c Kernel subimage has wrong type
1834 107 common/cmd_bootm.c Kernel subimage type OK
1835 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1836 108 common/cmd_bootm.c Got kernel subimage data/size
1837 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1838 -109 common/cmd_bootm.c Can't get kernel subimage type
1839 -110 common/cmd_bootm.c Can't get kernel subimage comp
1840 -111 common/cmd_bootm.c Can't get kernel subimage os
1841 -112 common/cmd_bootm.c Can't get kernel subimage load address
1842 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1844 120 common/image.c Start initial ramdisk verification
1845 -120 common/image.c Ramdisk FIT image has incorrect format
1846 121 common/image.c Ramdisk FIT image has correct format
1847 122 common/image.c No ramdisk subimage unit name, using configuration
1848 -122 common/image.c Can't get configuration for ramdisk subimage
1849 123 common/image.c Ramdisk unit name specified
1850 -124 common/image.c Can't get ramdisk subimage node offset
1851 125 common/image.c Got ramdisk subimage node offset
1852 -125 common/image.c Ramdisk subimage hash verification failed
1853 126 common/image.c Ramdisk subimage hash verification OK
1854 -126 common/image.c Ramdisk subimage for unsupported architecture
1855 127 common/image.c Architecture check OK
1856 -127 common/image.c Can't get ramdisk subimage data/size
1857 128 common/image.c Got ramdisk subimage data/size
1858 129 common/image.c Can't get ramdisk load address
1859 -129 common/image.c Got ramdisk load address
1861 -130 common/cmd_doc.c Incorrect FIT image format
1862 131 common/cmd_doc.c FIT image format OK
1864 -140 common/cmd_ide.c Incorrect FIT image format
1865 141 common/cmd_ide.c FIT image format OK
1867 -150 common/cmd_nand.c Incorrect FIT image format
1868 151 common/cmd_nand.c FIT image format OK
1874 [so far only for SMDK2400 and TRAB boards]
1876 - Modem support enable:
1877 CONFIG_MODEM_SUPPORT
1879 - RTS/CTS Flow control enable:
1882 - Modem debug support:
1883 CONFIG_MODEM_SUPPORT_DEBUG
1885 Enables debugging stuff (char screen[1024], dbg())
1886 for modem support. Useful only with BDI2000.
1888 - Interrupt support (PPC):
1890 There are common interrupt_init() and timer_interrupt()
1891 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1892 for CPU specific initialization. interrupt_init_cpu()
1893 should set decrementer_count to appropriate value. If
1894 CPU resets decrementer automatically after interrupt
1895 (ppc4xx) it should set decrementer_count to zero.
1896 timer_interrupt() calls timer_interrupt_cpu() for CPU
1897 specific handling. If board has watchdog / status_led
1898 / other_activity_monitor it works automatically from
1899 general timer_interrupt().
1903 In the target system modem support is enabled when a
1904 specific key (key combination) is pressed during
1905 power-on. Otherwise U-Boot will boot normally
1906 (autoboot). The key_pressed() function is called from
1907 board_init(). Currently key_pressed() is a dummy
1908 function, returning 1 and thus enabling modem
1911 If there are no modem init strings in the
1912 environment, U-Boot proceed to autoboot; the
1913 previous output (banner, info printfs) will be
1916 See also: doc/README.Modem
1919 Configuration Settings:
1920 -----------------------
1922 - CFG_LONGHELP: Defined when you want long help messages included;
1923 undefine this when you're short of memory.
1925 - CFG_PROMPT: This is what U-Boot prints on the console to
1926 prompt for user input.
1928 - CFG_CBSIZE: Buffer size for input from the Console
1930 - CFG_PBSIZE: Buffer size for Console output
1932 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1934 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1935 the application (usually a Linux kernel) when it is
1938 - CFG_BAUDRATE_TABLE:
1939 List of legal baudrate settings for this board.
1941 - CFG_CONSOLE_INFO_QUIET
1942 Suppress display of console information at boot.
1944 - CFG_CONSOLE_IS_IN_ENV
1945 If the board specific function
1946 extern int overwrite_console (void);
1947 returns 1, the stdin, stderr and stdout are switched to the
1948 serial port, else the settings in the environment are used.
1950 - CFG_CONSOLE_OVERWRITE_ROUTINE
1951 Enable the call to overwrite_console().
1953 - CFG_CONSOLE_ENV_OVERWRITE
1954 Enable overwrite of previous console environment settings.
1956 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1957 Begin and End addresses of the area used by the
1961 Enable an alternate, more extensive memory test.
1963 - CFG_MEMTEST_SCRATCH:
1964 Scratch address used by the alternate memory test
1965 You only need to set this if address zero isn't writeable
1967 - CFG_MEM_TOP_HIDE (PPC only):
1968 If CFG_MEM_TOP_HIDE is defined in the board config header,
1969 this specified memory area will get subtracted from the top
1970 (end) of RAM and won't get "touched" at all by U-Boot. By
1971 fixing up gd->ram_size the Linux kernel should gets passed
1972 the now "corrected" memory size and won't touch it either.
1973 This should work for arch/ppc and arch/powerpc. Only Linux
1974 board ports in arch/powerpc with bootwrapper support that
1975 recalculate the memory size from the SDRAM controller setup
1976 will have to get fixed in Linux additionally.
1978 This option can be used as a workaround for the 440EPx/GRx
1979 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1982 WARNING: Please make sure that this value is a multiple of
1983 the Linux page size (normally 4k). If this is not the case,
1984 then the end address of the Linux memory will be located at a
1985 non page size aligned address and this could cause major
1988 - CFG_TFTP_LOADADDR:
1989 Default load address for network file downloads
1991 - CFG_LOADS_BAUD_CHANGE:
1992 Enable temporary baudrate change while serial download
1995 Physical start address of SDRAM. _Must_ be 0 here.
1998 Physical start address of Motherboard I/O (if using a
2002 Physical start address of Flash memory.
2005 Physical start address of boot monitor code (set by
2006 make config files to be same as the text base address
2007 (TEXT_BASE) used when linking) - same as
2008 CFG_FLASH_BASE when booting from flash.
2011 Size of memory reserved for monitor code, used to
2012 determine _at_compile_time_ (!) if the environment is
2013 embedded within the U-Boot image, or in a separate
2017 Size of DRAM reserved for malloc() use.
2020 Normally compressed uImages are limited to an
2021 uncompressed size of 8 MBytes. If this is not enough,
2022 you can define CFG_BOOTM_LEN in your board config file
2023 to adjust this setting to your needs.
2026 Maximum size of memory mapped by the startup code of
2027 the Linux kernel; all data that must be processed by
2028 the Linux kernel (bd_info, boot arguments, FDT blob if
2029 used) must be put below this limit, unless "bootm_low"
2030 enviroment variable is defined and non-zero. In such case
2031 all data for the Linux kernel must be between "bootm_low"
2032 and "bootm_low" + CFG_BOOTMAPSZ.
2034 - CFG_MAX_FLASH_BANKS:
2035 Max number of Flash memory banks
2037 - CFG_MAX_FLASH_SECT:
2038 Max number of sectors on a Flash chip
2040 - CFG_FLASH_ERASE_TOUT:
2041 Timeout for Flash erase operations (in ms)
2043 - CFG_FLASH_WRITE_TOUT:
2044 Timeout for Flash write operations (in ms)
2046 - CFG_FLASH_LOCK_TOUT
2047 Timeout for Flash set sector lock bit operation (in ms)
2049 - CFG_FLASH_UNLOCK_TOUT
2050 Timeout for Flash clear lock bits operation (in ms)
2052 - CFG_FLASH_PROTECTION
2053 If defined, hardware flash sectors protection is used
2054 instead of U-Boot software protection.
2056 - CFG_DIRECT_FLASH_TFTP:
2058 Enable TFTP transfers directly to flash memory;
2059 without this option such a download has to be
2060 performed in two steps: (1) download to RAM, and (2)
2061 copy from RAM to flash.
2063 The two-step approach is usually more reliable, since
2064 you can check if the download worked before you erase
2065 the flash, but in some situations (when system RAM is
2066 too limited to allow for a temporary copy of the
2067 downloaded image) this option may be very useful.
2070 Define if the flash driver uses extra elements in the
2071 common flash structure for storing flash geometry.
2073 - CONFIG_FLASH_CFI_DRIVER
2074 This option also enables the building of the cfi_flash driver
2075 in the drivers directory
2077 - CFG_FLASH_USE_BUFFER_WRITE
2078 Use buffered writes to flash.
2080 - CONFIG_FLASH_SPANSION_S29WS_N
2081 s29ws-n MirrorBit flash has non-standard addresses for buffered
2084 - CFG_FLASH_QUIET_TEST
2085 If this option is defined, the common CFI flash doesn't
2086 print it's warning upon not recognized FLASH banks. This
2087 is useful, if some of the configured banks are only
2088 optionally available.
2090 - CONFIG_FLASH_SHOW_PROGRESS
2091 If defined (must be an integer), print out countdown
2092 digits and dots. Recommended value: 45 (9..1) for 80
2093 column displays, 15 (3..1) for 40 column displays.
2095 - CFG_RX_ETH_BUFFER:
2096 Defines the number of Ethernet receive buffers. On some
2097 Ethernet controllers it is recommended to set this value
2098 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2099 buffers can be full shortly after enabling the interface
2100 on high Ethernet traffic.
2101 Defaults to 4 if not defined.
2103 The following definitions that deal with the placement and management
2104 of environment data (variable area); in general, we support the
2105 following configurations:
2107 - CFG_ENV_IS_IN_FLASH:
2109 Define this if the environment is in flash memory.
2111 a) The environment occupies one whole flash sector, which is
2112 "embedded" in the text segment with the U-Boot code. This
2113 happens usually with "bottom boot sector" or "top boot
2114 sector" type flash chips, which have several smaller
2115 sectors at the start or the end. For instance, such a
2116 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2117 such a case you would place the environment in one of the
2118 4 kB sectors - with U-Boot code before and after it. With
2119 "top boot sector" type flash chips, you would put the
2120 environment in one of the last sectors, leaving a gap
2121 between U-Boot and the environment.
2125 Offset of environment data (variable area) to the
2126 beginning of flash memory; for instance, with bottom boot
2127 type flash chips the second sector can be used: the offset
2128 for this sector is given here.
2130 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2134 This is just another way to specify the start address of
2135 the flash sector containing the environment (instead of
2138 - CFG_ENV_SECT_SIZE:
2140 Size of the sector containing the environment.
2143 b) Sometimes flash chips have few, equal sized, BIG sectors.
2144 In such a case you don't want to spend a whole sector for
2149 If you use this in combination with CFG_ENV_IS_IN_FLASH
2150 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2151 of this flash sector for the environment. This saves
2152 memory for the RAM copy of the environment.
2154 It may also save flash memory if you decide to use this
2155 when your environment is "embedded" within U-Boot code,
2156 since then the remainder of the flash sector could be used
2157 for U-Boot code. It should be pointed out that this is
2158 STRONGLY DISCOURAGED from a robustness point of view:
2159 updating the environment in flash makes it always
2160 necessary to erase the WHOLE sector. If something goes
2161 wrong before the contents has been restored from a copy in
2162 RAM, your target system will be dead.
2164 - CFG_ENV_ADDR_REDUND
2167 These settings describe a second storage area used to hold
2168 a redundant copy of the environment data, so that there is
2169 a valid backup copy in case there is a power failure during
2170 a "saveenv" operation.
2172 BE CAREFUL! Any changes to the flash layout, and some changes to the
2173 source code will make it necessary to adapt <board>/u-boot.lds*
2177 - CFG_ENV_IS_IN_NVRAM:
2179 Define this if you have some non-volatile memory device
2180 (NVRAM, battery buffered SRAM) which you want to use for the
2186 These two #defines are used to determine the memory area you
2187 want to use for environment. It is assumed that this memory
2188 can just be read and written to, without any special
2191 BE CAREFUL! The first access to the environment happens quite early
2192 in U-Boot initalization (when we try to get the setting of for the
2193 console baudrate). You *MUST* have mapped your NVRAM area then, or
2196 Please note that even with NVRAM we still use a copy of the
2197 environment in RAM: we could work on NVRAM directly, but we want to
2198 keep settings there always unmodified except somebody uses "saveenv"
2199 to save the current settings.
2202 - CONFIG_ENV_IS_IN_EEPROM:
2204 Use this if you have an EEPROM or similar serial access
2205 device and a driver for it.
2210 These two #defines specify the offset and size of the
2211 environment area within the total memory of your EEPROM.
2213 - CFG_I2C_EEPROM_ADDR:
2214 If defined, specified the chip address of the EEPROM device.
2215 The default address is zero.
2217 - CFG_EEPROM_PAGE_WRITE_BITS:
2218 If defined, the number of bits used to address bytes in a
2219 single page in the EEPROM device. A 64 byte page, for example
2220 would require six bits.
2222 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2223 If defined, the number of milliseconds to delay between
2224 page writes. The default is zero milliseconds.
2226 - CFG_I2C_EEPROM_ADDR_LEN:
2227 The length in bytes of the EEPROM memory array address. Note
2228 that this is NOT the chip address length!
2230 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2231 EEPROM chips that implement "address overflow" are ones
2232 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2233 address and the extra bits end up in the "chip address" bit
2234 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2237 Note that we consider the length of the address field to
2238 still be one byte because the extra address bits are hidden
2239 in the chip address.
2242 The size in bytes of the EEPROM device.
2245 - CFG_ENV_IS_IN_DATAFLASH:
2247 Define this if you have a DataFlash memory device which you
2248 want to use for the environment.
2254 These three #defines specify the offset and size of the
2255 environment area within the total memory of your DataFlash placed
2256 at the specified address.
2258 - CFG_ENV_IS_IN_NAND:
2260 Define this if you have a NAND device which you want to use
2261 for the environment.
2266 These two #defines specify the offset and size of the environment
2267 area within the first NAND device.
2269 - CFG_ENV_OFFSET_REDUND
2271 This setting describes a second storage area of CFG_ENV_SIZE
2272 size used to hold a redundant copy of the environment data,
2273 so that there is a valid backup copy in case there is a
2274 power failure during a "saveenv" operation.
2276 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2277 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2278 the NAND devices block size.
2280 - CFG_SPI_INIT_OFFSET
2282 Defines offset to the initial SPI buffer area in DPRAM. The
2283 area is used at an early stage (ROM part) if the environment
2284 is configured to reside in the SPI EEPROM: We need a 520 byte
2285 scratch DPRAM area. It is used between the two initialization
2286 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2287 to be a good choice since it makes it far enough from the
2288 start of the data area as well as from the stack pointer.
2290 Please note that the environment is read-only until the monitor
2291 has been relocated to RAM and a RAM copy of the environment has been
2292 created; also, when using EEPROM you will have to use getenv_r()
2293 until then to read environment variables.
2295 The environment is protected by a CRC32 checksum. Before the monitor
2296 is relocated into RAM, as a result of a bad CRC you will be working
2297 with the compiled-in default environment - *silently*!!! [This is
2298 necessary, because the first environment variable we need is the
2299 "baudrate" setting for the console - if we have a bad CRC, we don't
2300 have any device yet where we could complain.]
2302 Note: once the monitor has been relocated, then it will complain if
2303 the default environment is used; a new CRC is computed as soon as you
2304 use the "saveenv" command to store a valid environment.
2306 - CFG_FAULT_ECHO_LINK_DOWN:
2307 Echo the inverted Ethernet link state to the fault LED.
2309 Note: If this option is active, then CFG_FAULT_MII_ADDR
2310 also needs to be defined.
2312 - CFG_FAULT_MII_ADDR:
2313 MII address of the PHY to check for the Ethernet link state.
2315 - CFG_64BIT_VSPRINTF:
2316 Makes vsprintf (and all *printf functions) support printing
2317 of 64bit values by using the L quantifier
2319 - CFG_64BIT_STRTOUL:
2320 Adds simple_strtoull that returns a 64bit value
2322 Low Level (hardware related) configuration options:
2323 ---------------------------------------------------
2325 - CFG_CACHELINE_SIZE:
2326 Cache Line Size of the CPU.
2329 Default address of the IMMR after system reset.
2331 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2332 and RPXsuper) to be able to adjust the position of
2333 the IMMR register after a reset.
2335 - Floppy Disk Support:
2336 CFG_FDC_DRIVE_NUMBER
2338 the default drive number (default value 0)
2342 defines the spacing between FDC chipset registers
2347 defines the offset of register from address. It
2348 depends on which part of the data bus is connected to
2349 the FDC chipset. (default value 0)
2351 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2352 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2355 if CFG_FDC_HW_INIT is defined, then the function
2356 fdc_hw_init() is called at the beginning of the FDC
2357 setup. fdc_hw_init() must be provided by the board
2358 source code. It is used to make hardware dependant
2361 - CFG_IMMR: Physical address of the Internal Memory.
2362 DO NOT CHANGE unless you know exactly what you're
2363 doing! (11-4) [MPC8xx/82xx systems only]
2365 - CFG_INIT_RAM_ADDR:
2367 Start address of memory area that can be used for
2368 initial data and stack; please note that this must be
2369 writable memory that is working WITHOUT special
2370 initialization, i. e. you CANNOT use normal RAM which
2371 will become available only after programming the
2372 memory controller and running certain initialization
2375 U-Boot uses the following memory types:
2376 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2377 - MPC824X: data cache
2378 - PPC4xx: data cache
2380 - CFG_GBL_DATA_OFFSET:
2382 Offset of the initial data structure in the memory
2383 area defined by CFG_INIT_RAM_ADDR. Usually
2384 CFG_GBL_DATA_OFFSET is chosen such that the initial
2385 data is located at the end of the available space
2386 (sometimes written as (CFG_INIT_RAM_END -
2387 CFG_INIT_DATA_SIZE), and the initial stack is just
2388 below that area (growing from (CFG_INIT_RAM_ADDR +
2389 CFG_GBL_DATA_OFFSET) downward.
2392 On the MPC824X (or other systems that use the data
2393 cache for initial memory) the address chosen for
2394 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2395 point to an otherwise UNUSED address space between
2396 the top of RAM and the start of the PCI space.
2398 - CFG_SIUMCR: SIU Module Configuration (11-6)
2400 - CFG_SYPCR: System Protection Control (11-9)
2402 - CFG_TBSCR: Time Base Status and Control (11-26)
2404 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2406 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2408 - CFG_SCCR: System Clock and reset Control Register (15-27)
2410 - CFG_OR_TIMING_SDRAM:
2414 periodic timer for refresh
2416 - CFG_DER: Debug Event Register (37-47)
2418 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2419 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2420 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2422 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2424 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2425 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2426 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2427 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2429 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2430 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2431 Machine Mode Register and Memory Periodic Timer
2432 Prescaler definitions (SDRAM timing)
2434 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2435 enable I2C microcode relocation patch (MPC8xx);
2436 define relocation offset in DPRAM [DSP2]
2438 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2439 enable SMC microcode relocation patch (MPC8xx);
2440 define relocation offset in DPRAM [SMC1]
2442 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2443 enable SPI microcode relocation patch (MPC8xx);
2444 define relocation offset in DPRAM [SCC4]
2447 Use OSCM clock mode on MBX8xx board. Be careful,
2448 wrong setting might damage your board. Read
2449 doc/README.MBX before setting this variable!
2451 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2452 Offset of the bootmode word in DPRAM used by post
2453 (Power On Self Tests). This definition overrides
2454 #define'd default value in commproc.h resp.
2457 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2458 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2459 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2460 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2461 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2462 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2463 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2464 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2465 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2468 Get DDR timing information from an I2C EEPROM. Common
2469 with pluggable memory modules such as SODIMMs
2472 I2C address of the SPD EEPROM
2475 If SPD EEPROM is on an I2C bus other than the first
2476 one, specify here. Note that the value must resolve
2477 to something your driver can deal with.
2479 - CFG_83XX_DDR_USES_CS0
2480 Only for 83xx systems. If specified, then DDR should
2481 be configured using CS0 and CS1 instead of CS2 and CS3.
2483 - CFG_83XX_DDR_USES_CS0
2484 Only for 83xx systems. If specified, then DDR should
2485 be configured using CS0 and CS1 instead of CS2 and CS3.
2487 - CONFIG_ETHER_ON_FEC[12]
2488 Define to enable FEC[12] on a 8xx series processor.
2490 - CONFIG_FEC[12]_PHY
2491 Define to the hardcoded PHY address which corresponds
2492 to the given FEC; i. e.
2493 #define CONFIG_FEC1_PHY 4
2494 means that the PHY with address 4 is connected to FEC1
2496 When set to -1, means to probe for first available.
2498 - CONFIG_FEC[12]_PHY_NORXERR
2499 The PHY does not have a RXERR line (RMII only).
2500 (so program the FEC to ignore it).
2503 Enable RMII mode for all FECs.
2504 Note that this is a global option, we can't
2505 have one FEC in standard MII mode and another in RMII mode.
2507 - CONFIG_CRC32_VERIFY
2508 Add a verify option to the crc32 command.
2511 => crc32 -v <address> <count> <crc32>
2513 Where address/count indicate a memory area
2514 and crc32 is the correct crc32 which the
2518 Add the "loopw" memory command. This only takes effect if
2519 the memory commands are activated globally (CONFIG_CMD_MEM).
2522 Add the "mdc" and "mwc" memory commands. These are cyclic
2527 This command will print 4 bytes (10,11,12,13) each 500 ms.
2529 => mwc.l 100 12345678 10
2530 This command will write 12345678 to address 100 all 10 ms.
2532 This only takes effect if the memory commands are activated
2533 globally (CONFIG_CMD_MEM).
2535 - CONFIG_SKIP_LOWLEVEL_INIT
2536 - CONFIG_SKIP_RELOCATE_UBOOT
2538 [ARM only] If these variables are defined, then
2539 certain low level initializations (like setting up
2540 the memory controller) are omitted and/or U-Boot does
2541 not relocate itself into RAM.
2542 Normally these variables MUST NOT be defined. The
2543 only exception is when U-Boot is loaded (to RAM) by
2544 some other boot loader or by a debugger which
2545 performs these initializations itself.
2548 Building the Software:
2549 ======================
2551 Building U-Boot has been tested in several native build environments
2552 and in many different cross environments. Of course we cannot support
2553 all possibly existing versions of cross development tools in all
2554 (potentially obsolete) versions. In case of tool chain problems we
2555 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2556 which is extensively used to build and test U-Boot.
2558 If you are not using a native environment, it is assumed that you
2559 have GNU cross compiling tools available in your path. In this case,
2560 you must set the environment variable CROSS_COMPILE in your shell.
2561 Note that no changes to the Makefile or any other source files are
2562 necessary. For example using the ELDK on a 4xx CPU, please enter:
2564 $ CROSS_COMPILE=ppc_4xx-
2565 $ export CROSS_COMPILE
2567 U-Boot is intended to be simple to build. After installing the
2568 sources you must configure U-Boot for one specific board type. This
2573 where "NAME_config" is the name of one of the existing configu-
2574 rations; see the main Makefile for supported names.
2576 Note: for some board special configuration names may exist; check if
2577 additional information is available from the board vendor; for
2578 instance, the TQM823L systems are available without (standard)
2579 or with LCD support. You can select such additional "features"
2580 when choosing the configuration, i. e.
2583 - will configure for a plain TQM823L, i. e. no LCD support
2585 make TQM823L_LCD_config
2586 - will configure for a TQM823L with U-Boot console on LCD
2591 Finally, type "make all", and you should get some working U-Boot
2592 images ready for download to / installation on your system:
2594 - "u-boot.bin" is a raw binary image
2595 - "u-boot" is an image in ELF binary format
2596 - "u-boot.srec" is in Motorola S-Record format
2598 By default the build is performed locally and the objects are saved
2599 in the source directory. One of the two methods can be used to change
2600 this behavior and build U-Boot to some external directory:
2602 1. Add O= to the make command line invocations:
2604 make O=/tmp/build distclean
2605 make O=/tmp/build NAME_config
2606 make O=/tmp/build all
2608 2. Set environment variable BUILD_DIR to point to the desired location:
2610 export BUILD_DIR=/tmp/build
2615 Note that the command line "O=" setting overrides the BUILD_DIR environment
2619 Please be aware that the Makefiles assume you are using GNU make, so
2620 for instance on NetBSD you might need to use "gmake" instead of
2624 If the system board that you have is not listed, then you will need
2625 to port U-Boot to your hardware platform. To do this, follow these
2628 1. Add a new configuration option for your board to the toplevel
2629 "Makefile" and to the "MAKEALL" script, using the existing
2630 entries as examples. Note that here and at many other places
2631 boards and other names are listed in alphabetical sort order. Please
2633 2. Create a new directory to hold your board specific code. Add any
2634 files you need. In your board directory, you will need at least
2635 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2636 3. Create a new configuration file "include/configs/<board>.h" for
2638 3. If you're porting U-Boot to a new CPU, then also create a new
2639 directory to hold your CPU specific code. Add any files you need.
2640 4. Run "make <board>_config" with your new name.
2641 5. Type "make", and you should get a working "u-boot.srec" file
2642 to be installed on your target system.
2643 6. Debug and solve any problems that might arise.
2644 [Of course, this last step is much harder than it sounds.]
2647 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2648 ==============================================================
2650 If you have modified U-Boot sources (for instance added a new board
2651 or support for new devices, a new CPU, etc.) you are expected to
2652 provide feedback to the other developers. The feedback normally takes
2653 the form of a "patch", i. e. a context diff against a certain (latest
2654 official or latest in the git repository) version of U-Boot sources.
2656 But before you submit such a patch, please verify that your modifi-
2657 cation did not break existing code. At least make sure that *ALL* of
2658 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2659 just run the "MAKEALL" script, which will configure and build U-Boot
2660 for ALL supported system. Be warned, this will take a while. You can
2661 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2662 environment variable to the script, i. e. to use the ELDK cross tools
2665 CROSS_COMPILE=ppc_8xx- MAKEALL
2667 or to build on a native PowerPC system you can type
2669 CROSS_COMPILE=' ' MAKEALL
2671 When using the MAKEALL script, the default behaviour is to build
2672 U-Boot in the source directory. This location can be changed by
2673 setting the BUILD_DIR environment variable. Also, for each target
2674 built, the MAKEALL script saves two log files (<target>.ERR and
2675 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2676 location can be changed by setting the MAKEALL_LOGDIR environment
2677 variable. For example:
2679 export BUILD_DIR=/tmp/build
2680 export MAKEALL_LOGDIR=/tmp/log
2681 CROSS_COMPILE=ppc_8xx- MAKEALL
2683 With the above settings build objects are saved in the /tmp/build,
2684 log files are saved in the /tmp/log and the source tree remains clean
2685 during the whole build process.
2688 See also "U-Boot Porting Guide" below.
2691 Monitor Commands - Overview:
2692 ============================
2694 go - start application at address 'addr'
2695 run - run commands in an environment variable
2696 bootm - boot application image from memory
2697 bootp - boot image via network using BootP/TFTP protocol
2698 tftpboot- boot image via network using TFTP protocol
2699 and env variables "ipaddr" and "serverip"
2700 (and eventually "gatewayip")
2701 rarpboot- boot image via network using RARP/TFTP protocol
2702 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2703 loads - load S-Record file over serial line
2704 loadb - load binary file over serial line (kermit mode)
2706 mm - memory modify (auto-incrementing)
2707 nm - memory modify (constant address)
2708 mw - memory write (fill)
2710 cmp - memory compare
2711 crc32 - checksum calculation
2712 imd - i2c memory display
2713 imm - i2c memory modify (auto-incrementing)
2714 inm - i2c memory modify (constant address)
2715 imw - i2c memory write (fill)
2716 icrc32 - i2c checksum calculation
2717 iprobe - probe to discover valid I2C chip addresses
2718 iloop - infinite loop on address range
2719 isdram - print SDRAM configuration information
2720 sspi - SPI utility commands
2721 base - print or set address offset
2722 printenv- print environment variables
2723 setenv - set environment variables
2724 saveenv - save environment variables to persistent storage
2725 protect - enable or disable FLASH write protection
2726 erase - erase FLASH memory
2727 flinfo - print FLASH memory information
2728 bdinfo - print Board Info structure
2729 iminfo - print header information for application image
2730 coninfo - print console devices and informations
2731 ide - IDE sub-system
2732 loop - infinite loop on address range
2733 loopw - infinite write loop on address range
2734 mtest - simple RAM test
2735 icache - enable or disable instruction cache
2736 dcache - enable or disable data cache
2737 reset - Perform RESET of the CPU
2738 echo - echo args to console
2739 version - print monitor version
2740 help - print online help
2741 ? - alias for 'help'
2744 Monitor Commands - Detailed Description:
2745 ========================================
2749 For now: just type "help <command>".
2752 Environment Variables:
2753 ======================
2755 U-Boot supports user configuration using Environment Variables which
2756 can be made persistent by saving to Flash memory.
2758 Environment Variables are set using "setenv", printed using
2759 "printenv", and saved to Flash using "saveenv". Using "setenv"
2760 without a value can be used to delete a variable from the
2761 environment. As long as you don't save the environment you are
2762 working with an in-memory copy. In case the Flash area containing the
2763 environment is erased by accident, a default environment is provided.
2765 Some configuration options can be set using Environment Variables:
2767 baudrate - see CONFIG_BAUDRATE
2769 bootdelay - see CONFIG_BOOTDELAY
2771 bootcmd - see CONFIG_BOOTCOMMAND
2773 bootargs - Boot arguments when booting an RTOS image
2775 bootfile - Name of the image to load with TFTP
2777 bootm_low - Memory range available for image processing in the bootm
2778 command can be restricted. This variable is given as
2779 a hexadecimal number and defines lowest address allowed
2780 for use by the bootm command. See also "bootm_size"
2781 environment variable. Address defined by "bootm_low" is
2782 also the base of the initial memory mapping for the Linux
2783 kernel -- see the description of CFG_BOOTMAPSZ.
2785 bootm_size - Memory range available for image processing in the bootm
2786 command can be restricted. This variable is given as
2787 a hexadecimal number and defines the size of the region
2788 allowed for use by the bootm command. See also "bootm_low"
2789 environment variable.
2791 autoload - if set to "no" (any string beginning with 'n'),
2792 "bootp" will just load perform a lookup of the
2793 configuration from the BOOTP server, but not try to
2794 load any image using TFTP
2796 autoscript - if set to "yes" commands like "loadb", "loady",
2797 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2798 to automatically run script images (by internally
2799 calling "autoscript").
2801 autoscript_uname - if script image is in a format (FIT) this
2802 variable is used to get script subimage unit name.
2804 autostart - if set to "yes", an image loaded using the "bootp",
2805 "rarpboot", "tftpboot" or "diskboot" commands will
2806 be automatically started (by internally calling
2809 If set to "no", a standalone image passed to the
2810 "bootm" command will be copied to the load address
2811 (and eventually uncompressed), but NOT be started.
2812 This can be used to load and uncompress arbitrary
2815 i2cfast - (PPC405GP|PPC405EP only)
2816 if set to 'y' configures Linux I2C driver for fast
2817 mode (400kHZ). This environment variable is used in
2818 initialization code. So, for changes to be effective
2819 it must be saved and board must be reset.
2821 initrd_high - restrict positioning of initrd images:
2822 If this variable is not set, initrd images will be
2823 copied to the highest possible address in RAM; this
2824 is usually what you want since it allows for
2825 maximum initrd size. If for some reason you want to
2826 make sure that the initrd image is loaded below the
2827 CFG_BOOTMAPSZ limit, you can set this environment
2828 variable to a value of "no" or "off" or "0".
2829 Alternatively, you can set it to a maximum upper
2830 address to use (U-Boot will still check that it
2831 does not overwrite the U-Boot stack and data).
2833 For instance, when you have a system with 16 MB
2834 RAM, and want to reserve 4 MB from use by Linux,
2835 you can do this by adding "mem=12M" to the value of
2836 the "bootargs" variable. However, now you must make
2837 sure that the initrd image is placed in the first
2838 12 MB as well - this can be done with
2840 setenv initrd_high 00c00000
2842 If you set initrd_high to 0xFFFFFFFF, this is an
2843 indication to U-Boot that all addresses are legal
2844 for the Linux kernel, including addresses in flash
2845 memory. In this case U-Boot will NOT COPY the
2846 ramdisk at all. This may be useful to reduce the
2847 boot time on your system, but requires that this
2848 feature is supported by your Linux kernel.
2850 ipaddr - IP address; needed for tftpboot command
2852 loadaddr - Default load address for commands like "bootp",
2853 "rarpboot", "tftpboot", "loadb" or "diskboot"
2855 loads_echo - see CONFIG_LOADS_ECHO
2857 serverip - TFTP server IP address; needed for tftpboot command
2859 bootretry - see CONFIG_BOOT_RETRY_TIME
2861 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2863 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2865 ethprime - When CONFIG_NET_MULTI is enabled controls which
2866 interface is used first.
2868 ethact - When CONFIG_NET_MULTI is enabled controls which
2869 interface is currently active. For example you
2870 can do the following
2872 => setenv ethact FEC ETHERNET
2873 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2874 => setenv ethact SCC ETHERNET
2875 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2877 ethrotate - When set to "no" U-Boot does not go through all
2878 available network interfaces.
2879 It just stays at the currently selected interface.
2881 netretry - When set to "no" each network operation will
2882 either succeed or fail without retrying.
2883 When set to "once" the network operation will
2884 fail when all the available network interfaces
2885 are tried once without success.
2886 Useful on scripts which control the retry operation
2889 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2890 if set load address for the NPE microcode
2892 tftpsrcport - If this is set, the value is used for TFTP's
2895 tftpdstport - If this is set, the value is used for TFTP's UDP
2896 destination port instead of the Well Know Port 69.
2898 vlan - When set to a value < 4095 the traffic over
2899 Ethernet is encapsulated/received over 802.1q
2902 The following environment variables may be used and automatically
2903 updated by the network boot commands ("bootp" and "rarpboot"),
2904 depending the information provided by your boot server:
2906 bootfile - see above
2907 dnsip - IP address of your Domain Name Server
2908 dnsip2 - IP address of your secondary Domain Name Server
2909 gatewayip - IP address of the Gateway (Router) to use
2910 hostname - Target hostname
2912 netmask - Subnet Mask
2913 rootpath - Pathname of the root filesystem on the NFS server
2914 serverip - see above
2917 There are two special Environment Variables:
2919 serial# - contains hardware identification information such
2920 as type string and/or serial number
2921 ethaddr - Ethernet address
2923 These variables can be set only once (usually during manufacturing of
2924 the board). U-Boot refuses to delete or overwrite these variables
2925 once they have been set once.
2928 Further special Environment Variables:
2930 ver - Contains the U-Boot version string as printed
2931 with the "version" command. This variable is
2932 readonly (see CONFIG_VERSION_VARIABLE).
2935 Please note that changes to some configuration parameters may take
2936 only effect after the next boot (yes, that's just like Windoze :-).
2939 Command Line Parsing:
2940 =====================
2942 There are two different command line parsers available with U-Boot:
2943 the old "simple" one, and the much more powerful "hush" shell:
2945 Old, simple command line parser:
2946 --------------------------------
2948 - supports environment variables (through setenv / saveenv commands)
2949 - several commands on one line, separated by ';'
2950 - variable substitution using "... ${name} ..." syntax
2951 - special characters ('$', ';') can be escaped by prefixing with '\',
2953 setenv bootcmd bootm \${address}
2954 - You can also escape text by enclosing in single apostrophes, for example:
2955 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2960 - similar to Bourne shell, with control structures like
2961 if...then...else...fi, for...do...done; while...do...done,
2962 until...do...done, ...
2963 - supports environment ("global") variables (through setenv / saveenv
2964 commands) and local shell variables (through standard shell syntax
2965 "name=value"); only environment variables can be used with "run"
2971 (1) If a command line (or an environment variable executed by a "run"
2972 command) contains several commands separated by semicolon, and
2973 one of these commands fails, then the remaining commands will be
2976 (2) If you execute several variables with one call to run (i. e.
2977 calling run with a list of variables as arguments), any failing
2978 command will cause "run" to terminate, i. e. the remaining
2979 variables are not executed.
2981 Note for Redundant Ethernet Interfaces:
2982 =======================================
2984 Some boards come with redundant Ethernet interfaces; U-Boot supports
2985 such configurations and is capable of automatic selection of a
2986 "working" interface when needed. MAC assignment works as follows:
2988 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2989 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2990 "eth1addr" (=>eth1), "eth2addr", ...
2992 If the network interface stores some valid MAC address (for instance
2993 in SROM), this is used as default address if there is NO correspon-
2994 ding setting in the environment; if the corresponding environment
2995 variable is set, this overrides the settings in the card; that means:
2997 o If the SROM has a valid MAC address, and there is no address in the
2998 environment, the SROM's address is used.
3000 o If there is no valid address in the SROM, and a definition in the
3001 environment exists, then the value from the environment variable is
3004 o If both the SROM and the environment contain a MAC address, and
3005 both addresses are the same, this MAC address is used.
3007 o If both the SROM and the environment contain a MAC address, and the
3008 addresses differ, the value from the environment is used and a
3011 o If neither SROM nor the environment contain a MAC address, an error
3018 U-Boot is capable of booting (and performing other auxiliary operations on)
3019 images in two formats:
3021 New uImage format (FIT)
3022 -----------------------
3024 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3025 to Flattened Device Tree). It allows the use of images with multiple
3026 components (several kernels, ramdisks, etc.), with contents protected by
3027 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3033 Old image format is based on binary files which can be basically anything,
3034 preceded by a special header; see the definitions in include/image.h for
3035 details; basically, the header defines the following image properties:
3037 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3038 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3039 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3040 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3042 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3043 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3044 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3045 * Compression Type (uncompressed, gzip, bzip2)
3051 The header is marked by a special Magic Number, and both the header
3052 and the data portions of the image are secured against corruption by
3059 Although U-Boot should support any OS or standalone application
3060 easily, the main focus has always been on Linux during the design of
3063 U-Boot includes many features that so far have been part of some
3064 special "boot loader" code within the Linux kernel. Also, any
3065 "initrd" images to be used are no longer part of one big Linux image;
3066 instead, kernel and "initrd" are separate images. This implementation
3067 serves several purposes:
3069 - the same features can be used for other OS or standalone
3070 applications (for instance: using compressed images to reduce the
3071 Flash memory footprint)
3073 - it becomes much easier to port new Linux kernel versions because
3074 lots of low-level, hardware dependent stuff are done by U-Boot
3076 - the same Linux kernel image can now be used with different "initrd"
3077 images; of course this also means that different kernel images can
3078 be run with the same "initrd". This makes testing easier (you don't
3079 have to build a new "zImage.initrd" Linux image when you just
3080 change a file in your "initrd"). Also, a field-upgrade of the
3081 software is easier now.
3087 Porting Linux to U-Boot based systems:
3088 ---------------------------------------
3090 U-Boot cannot save you from doing all the necessary modifications to
3091 configure the Linux device drivers for use with your target hardware
3092 (no, we don't intend to provide a full virtual machine interface to
3095 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3097 Just make sure your machine specific header file (for instance
3098 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3099 Information structure as we define in include/asm-<arch>/u-boot.h,
3100 and make sure that your definition of IMAP_ADDR uses the same value
3101 as your U-Boot configuration in CFG_IMMR.
3104 Configuring the Linux kernel:
3105 -----------------------------
3107 No specific requirements for U-Boot. Make sure you have some root
3108 device (initial ramdisk, NFS) for your target system.
3111 Building a Linux Image:
3112 -----------------------
3114 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3115 not used. If you use recent kernel source, a new build target
3116 "uImage" will exist which automatically builds an image usable by
3117 U-Boot. Most older kernels also have support for a "pImage" target,
3118 which was introduced for our predecessor project PPCBoot and uses a
3119 100% compatible format.
3128 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3129 encapsulate a compressed Linux kernel image with header information,
3130 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3132 * build a standard "vmlinux" kernel image (in ELF binary format):
3134 * convert the kernel into a raw binary image:
3136 ${CROSS_COMPILE}-objcopy -O binary \
3137 -R .note -R .comment \
3138 -S vmlinux linux.bin
3140 * compress the binary image:
3144 * package compressed binary image for U-Boot:
3146 mkimage -A ppc -O linux -T kernel -C gzip \
3147 -a 0 -e 0 -n "Linux Kernel Image" \
3148 -d linux.bin.gz uImage
3151 The "mkimage" tool can also be used to create ramdisk images for use
3152 with U-Boot, either separated from the Linux kernel image, or
3153 combined into one file. "mkimage" encapsulates the images with a 64
3154 byte header containing information about target architecture,
3155 operating system, image type, compression method, entry points, time
3156 stamp, CRC32 checksums, etc.
3158 "mkimage" can be called in two ways: to verify existing images and
3159 print the header information, or to build new images.
3161 In the first form (with "-l" option) mkimage lists the information
3162 contained in the header of an existing U-Boot image; this includes
3163 checksum verification:
3165 tools/mkimage -l image
3166 -l ==> list image header information
3168 The second form (with "-d" option) is used to build a U-Boot image
3169 from a "data file" which is used as image payload:
3171 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3172 -n name -d data_file image
3173 -A ==> set architecture to 'arch'
3174 -O ==> set operating system to 'os'
3175 -T ==> set image type to 'type'
3176 -C ==> set compression type 'comp'
3177 -a ==> set load address to 'addr' (hex)
3178 -e ==> set entry point to 'ep' (hex)
3179 -n ==> set image name to 'name'
3180 -d ==> use image data from 'datafile'
3182 Right now, all Linux kernels for PowerPC systems use the same load
3183 address (0x00000000), but the entry point address depends on the
3186 - 2.2.x kernels have the entry point at 0x0000000C,
3187 - 2.3.x and later kernels have the entry point at 0x00000000.
3189 So a typical call to build a U-Boot image would read:
3191 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3192 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3193 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3194 > examples/uImage.TQM850L
3195 Image Name: 2.4.4 kernel for TQM850L
3196 Created: Wed Jul 19 02:34:59 2000
3197 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3198 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3199 Load Address: 0x00000000
3200 Entry Point: 0x00000000
3202 To verify the contents of the image (or check for corruption):
3204 -> tools/mkimage -l examples/uImage.TQM850L
3205 Image Name: 2.4.4 kernel for TQM850L
3206 Created: Wed Jul 19 02:34:59 2000
3207 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3208 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3209 Load Address: 0x00000000
3210 Entry Point: 0x00000000
3212 NOTE: for embedded systems where boot time is critical you can trade
3213 speed for memory and install an UNCOMPRESSED image instead: this
3214 needs more space in Flash, but boots much faster since it does not
3215 need to be uncompressed:
3217 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3218 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3219 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3220 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3221 > examples/uImage.TQM850L-uncompressed
3222 Image Name: 2.4.4 kernel for TQM850L
3223 Created: Wed Jul 19 02:34:59 2000
3224 Image Type: PowerPC Linux Kernel Image (uncompressed)
3225 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3226 Load Address: 0x00000000
3227 Entry Point: 0x00000000
3230 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3231 when your kernel is intended to use an initial ramdisk:
3233 -> tools/mkimage -n 'Simple Ramdisk Image' \
3234 > -A ppc -O linux -T ramdisk -C gzip \
3235 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3236 Image Name: Simple Ramdisk Image
3237 Created: Wed Jan 12 14:01:50 2000
3238 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3239 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3240 Load Address: 0x00000000
3241 Entry Point: 0x00000000
3244 Installing a Linux Image:
3245 -------------------------
3247 To downloading a U-Boot image over the serial (console) interface,
3248 you must convert the image to S-Record format:
3250 objcopy -I binary -O srec examples/image examples/image.srec
3252 The 'objcopy' does not understand the information in the U-Boot
3253 image header, so the resulting S-Record file will be relative to
3254 address 0x00000000. To load it to a given address, you need to
3255 specify the target address as 'offset' parameter with the 'loads'
3258 Example: install the image to address 0x40100000 (which on the
3259 TQM8xxL is in the first Flash bank):
3261 => erase 40100000 401FFFFF
3267 ## Ready for S-Record download ...
3268 ~>examples/image.srec
3269 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3271 15989 15990 15991 15992
3272 [file transfer complete]
3274 ## Start Addr = 0x00000000
3277 You can check the success of the download using the 'iminfo' command;
3278 this includes a checksum verification so you can be sure no data
3279 corruption happened:
3283 ## Checking Image at 40100000 ...
3284 Image Name: 2.2.13 for initrd on TQM850L
3285 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3286 Data Size: 335725 Bytes = 327 kB = 0 MB
3287 Load Address: 00000000
3288 Entry Point: 0000000c
3289 Verifying Checksum ... OK
3295 The "bootm" command is used to boot an application that is stored in
3296 memory (RAM or Flash). In case of a Linux kernel image, the contents
3297 of the "bootargs" environment variable is passed to the kernel as
3298 parameters. You can check and modify this variable using the
3299 "printenv" and "setenv" commands:
3302 => printenv bootargs
3303 bootargs=root=/dev/ram
3305 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3307 => printenv bootargs
3308 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3311 ## Booting Linux kernel at 40020000 ...
3312 Image Name: 2.2.13 for NFS on TQM850L
3313 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3314 Data Size: 381681 Bytes = 372 kB = 0 MB
3315 Load Address: 00000000
3316 Entry Point: 0000000c
3317 Verifying Checksum ... OK
3318 Uncompressing Kernel Image ... OK
3319 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
3320 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3321 time_init: decrementer frequency = 187500000/60
3322 Calibrating delay loop... 49.77 BogoMIPS
3323 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3326 If you want to boot a Linux kernel with initial RAM disk, you pass
3327 the memory addresses of both the kernel and the initrd image (PPBCOOT
3328 format!) to the "bootm" command:
3330 => imi 40100000 40200000
3332 ## Checking Image at 40100000 ...
3333 Image Name: 2.2.13 for initrd on TQM850L
3334 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3335 Data Size: 335725 Bytes = 327 kB = 0 MB
3336 Load Address: 00000000
3337 Entry Point: 0000000c
3338 Verifying Checksum ... OK
3340 ## Checking Image at 40200000 ...
3341 Image Name: Simple Ramdisk Image
3342 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3343 Data Size: 566530 Bytes = 553 kB = 0 MB
3344 Load Address: 00000000
3345 Entry Point: 00000000
3346 Verifying Checksum ... OK
3348 => bootm 40100000 40200000
3349 ## Booting Linux kernel at 40100000 ...
3350 Image Name: 2.2.13 for initrd on TQM850L
3351 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3352 Data Size: 335725 Bytes = 327 kB = 0 MB
3353 Load Address: 00000000
3354 Entry Point: 0000000c
3355 Verifying Checksum ... OK
3356 Uncompressing Kernel Image ... OK
3357 ## Loading RAMDisk Image at 40200000 ...
3358 Image Name: Simple Ramdisk Image
3359 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3360 Data Size: 566530 Bytes = 553 kB = 0 MB
3361 Load Address: 00000000
3362 Entry Point: 00000000
3363 Verifying Checksum ... OK
3364 Loading Ramdisk ... OK
3365 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
3366 Boot arguments: root=/dev/ram
3367 time_init: decrementer frequency = 187500000/60
3368 Calibrating delay loop... 49.77 BogoMIPS
3370 RAMDISK: Compressed image found at block 0
3371 VFS: Mounted root (ext2 filesystem).
3375 Boot Linux and pass a flat device tree:
3378 First, U-Boot must be compiled with the appropriate defines. See the section
3379 titled "Linux Kernel Interface" above for a more in depth explanation. The
3380 following is an example of how to start a kernel and pass an updated
3386 oft=oftrees/mpc8540ads.dtb
3387 => tftp $oftaddr $oft
3388 Speed: 1000, full duplex
3390 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3391 Filename 'oftrees/mpc8540ads.dtb'.
3392 Load address: 0x300000
3395 Bytes transferred = 4106 (100a hex)
3396 => tftp $loadaddr $bootfile
3397 Speed: 1000, full duplex
3399 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3401 Load address: 0x200000
3402 Loading:############
3404 Bytes transferred = 1029407 (fb51f hex)
3409 => bootm $loadaddr - $oftaddr
3410 ## Booting image at 00200000 ...
3411 Image Name: Linux-2.6.17-dirty
3412 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3413 Data Size: 1029343 Bytes = 1005.2 kB
3414 Load Address: 00000000
3415 Entry Point: 00000000
3416 Verifying Checksum ... OK
3417 Uncompressing Kernel Image ... OK
3418 Booting using flat device tree at 0x300000
3419 Using MPC85xx ADS machine description
3420 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3424 More About U-Boot Image Types:
3425 ------------------------------
3427 U-Boot supports the following image types:
3429 "Standalone Programs" are directly runnable in the environment
3430 provided by U-Boot; it is expected that (if they behave
3431 well) you can continue to work in U-Boot after return from
3432 the Standalone Program.
3433 "OS Kernel Images" are usually images of some Embedded OS which
3434 will take over control completely. Usually these programs
3435 will install their own set of exception handlers, device
3436 drivers, set up the MMU, etc. - this means, that you cannot
3437 expect to re-enter U-Boot except by resetting the CPU.
3438 "RAMDisk Images" are more or less just data blocks, and their
3439 parameters (address, size) are passed to an OS kernel that is
3441 "Multi-File Images" contain several images, typically an OS
3442 (Linux) kernel image and one or more data images like
3443 RAMDisks. This construct is useful for instance when you want
3444 to boot over the network using BOOTP etc., where the boot
3445 server provides just a single image file, but you want to get
3446 for instance an OS kernel and a RAMDisk image.
3448 "Multi-File Images" start with a list of image sizes, each
3449 image size (in bytes) specified by an "uint32_t" in network
3450 byte order. This list is terminated by an "(uint32_t)0".
3451 Immediately after the terminating 0 follow the images, one by
3452 one, all aligned on "uint32_t" boundaries (size rounded up to
3453 a multiple of 4 bytes).
3455 "Firmware Images" are binary images containing firmware (like
3456 U-Boot or FPGA images) which usually will be programmed to
3459 "Script files" are command sequences that will be executed by
3460 U-Boot's command interpreter; this feature is especially
3461 useful when you configure U-Boot to use a real shell (hush)
3462 as command interpreter.
3468 One of the features of U-Boot is that you can dynamically load and
3469 run "standalone" applications, which can use some resources of
3470 U-Boot like console I/O functions or interrupt services.
3472 Two simple examples are included with the sources:
3477 'examples/hello_world.c' contains a small "Hello World" Demo
3478 application; it is automatically compiled when you build U-Boot.
3479 It's configured to run at address 0x00040004, so you can play with it
3483 ## Ready for S-Record download ...
3484 ~>examples/hello_world.srec
3485 1 2 3 4 5 6 7 8 9 10 11 ...
3486 [file transfer complete]
3488 ## Start Addr = 0x00040004
3490 => go 40004 Hello World! This is a test.
3491 ## Starting application at 0x00040004 ...
3502 Hit any key to exit ...
3504 ## Application terminated, rc = 0x0
3506 Another example, which demonstrates how to register a CPM interrupt
3507 handler with the U-Boot code, can be found in 'examples/timer.c'.
3508 Here, a CPM timer is set up to generate an interrupt every second.
3509 The interrupt service routine is trivial, just printing a '.'
3510 character, but this is just a demo program. The application can be
3511 controlled by the following keys:
3513 ? - print current values og the CPM Timer registers
3514 b - enable interrupts and start timer
3515 e - stop timer and disable interrupts
3516 q - quit application
3519 ## Ready for S-Record download ...
3520 ~>examples/timer.srec
3521 1 2 3 4 5 6 7 8 9 10 11 ...
3522 [file transfer complete]
3524 ## Start Addr = 0x00040004
3527 ## Starting application at 0x00040004 ...
3530 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3533 [q, b, e, ?] Set interval 1000000 us
3536 [q, b, e, ?] ........
3537 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3540 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3543 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3546 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3548 [q, b, e, ?] ...Stopping timer
3550 [q, b, e, ?] ## Application terminated, rc = 0x0
3556 Over time, many people have reported problems when trying to use the
3557 "minicom" terminal emulation program for serial download. I (wd)
3558 consider minicom to be broken, and recommend not to use it. Under
3559 Unix, I recommend to use C-Kermit for general purpose use (and
3560 especially for kermit binary protocol download ("loadb" command), and
3561 use "cu" for S-Record download ("loads" command).
3563 Nevertheless, if you absolutely want to use it try adding this
3564 configuration to your "File transfer protocols" section:
3566 Name Program Name U/D FullScr IO-Red. Multi
3567 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3568 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3574 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3575 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3577 Building requires a cross environment; it is known to work on
3578 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3579 need gmake since the Makefiles are not compatible with BSD make).
3580 Note that the cross-powerpc package does not install include files;
3581 attempting to build U-Boot will fail because <machine/ansi.h> is
3582 missing. This file has to be installed and patched manually:
3584 # cd /usr/pkg/cross/powerpc-netbsd/include
3586 # ln -s powerpc machine
3587 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3588 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3590 Native builds *don't* work due to incompatibilities between native
3591 and U-Boot include files.
3593 Booting assumes that (the first part of) the image booted is a
3594 stage-2 loader which in turn loads and then invokes the kernel
3595 proper. Loader sources will eventually appear in the NetBSD source
3596 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3597 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3600 Implementation Internals:
3601 =========================
3603 The following is not intended to be a complete description of every
3604 implementation detail. However, it should help to understand the
3605 inner workings of U-Boot and make it easier to port it to custom
3609 Initial Stack, Global Data:
3610 ---------------------------
3612 The implementation of U-Boot is complicated by the fact that U-Boot
3613 starts running out of ROM (flash memory), usually without access to
3614 system RAM (because the memory controller is not initialized yet).
3615 This means that we don't have writable Data or BSS segments, and BSS
3616 is not initialized as zero. To be able to get a C environment working
3617 at all, we have to allocate at least a minimal stack. Implementation
3618 options for this are defined and restricted by the CPU used: Some CPU
3619 models provide on-chip memory (like the IMMR area on MPC8xx and
3620 MPC826x processors), on others (parts of) the data cache can be
3621 locked as (mis-) used as memory, etc.
3623 Chris Hallinan posted a good summary of these issues to the
3624 u-boot-users mailing list:
3626 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3627 From: "Chris Hallinan" <clh@net1plus.com>
3628 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3631 Correct me if I'm wrong, folks, but the way I understand it
3632 is this: Using DCACHE as initial RAM for Stack, etc, does not
3633 require any physical RAM backing up the cache. The cleverness
3634 is that the cache is being used as a temporary supply of
3635 necessary storage before the SDRAM controller is setup. It's
3636 beyond the scope of this list to explain the details, but you
3637 can see how this works by studying the cache architecture and
3638 operation in the architecture and processor-specific manuals.
3640 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3641 is another option for the system designer to use as an
3642 initial stack/RAM area prior to SDRAM being available. Either
3643 option should work for you. Using CS 4 should be fine if your
3644 board designers haven't used it for something that would
3645 cause you grief during the initial boot! It is frequently not
3648 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3649 with your processor/board/system design. The default value
3650 you will find in any recent u-boot distribution in
3651 walnut.h should work for you. I'd set it to a value larger
3652 than your SDRAM module. If you have a 64MB SDRAM module, set
3653 it above 400_0000. Just make sure your board has no resources
3654 that are supposed to respond to that address! That code in
3655 start.S has been around a while and should work as is when
3656 you get the config right.
3661 It is essential to remember this, since it has some impact on the C
3662 code for the initialization procedures:
3664 * Initialized global data (data segment) is read-only. Do not attempt
3667 * Do not use any uninitialized global data (or implicitely initialized
3668 as zero data - BSS segment) at all - this is undefined, initiali-
3669 zation is performed later (when relocating to RAM).
3671 * Stack space is very limited. Avoid big data buffers or things like
3674 Having only the stack as writable memory limits means we cannot use
3675 normal global data to share information beween the code. But it
3676 turned out that the implementation of U-Boot can be greatly
3677 simplified by making a global data structure (gd_t) available to all
3678 functions. We could pass a pointer to this data as argument to _all_
3679 functions, but this would bloat the code. Instead we use a feature of
3680 the GCC compiler (Global Register Variables) to share the data: we
3681 place a pointer (gd) to the global data into a register which we
3682 reserve for this purpose.
3684 When choosing a register for such a purpose we are restricted by the
3685 relevant (E)ABI specifications for the current architecture, and by
3686 GCC's implementation.
3688 For PowerPC, the following registers have specific use:
3690 R2: reserved for system use
3691 R3-R4: parameter passing and return values
3692 R5-R10: parameter passing
3693 R13: small data area pointer
3697 (U-Boot also uses R14 as internal GOT pointer.)
3699 ==> U-Boot will use R2 to hold a pointer to the global data
3701 Note: on PPC, we could use a static initializer (since the
3702 address of the global data structure is known at compile time),
3703 but it turned out that reserving a register results in somewhat
3704 smaller code - although the code savings are not that big (on
3705 average for all boards 752 bytes for the whole U-Boot image,
3706 624 text + 127 data).
3708 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3709 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3711 ==> U-Boot will use P5 to hold a pointer to the global data
3713 On ARM, the following registers are used:
3715 R0: function argument word/integer result
3716 R1-R3: function argument word
3718 R10: stack limit (used only if stack checking if enabled)
3719 R11: argument (frame) pointer
3720 R12: temporary workspace
3723 R15: program counter
3725 ==> U-Boot will use R8 to hold a pointer to the global data
3727 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3728 or current versions of GCC may "optimize" the code too much.
3733 U-Boot runs in system state and uses physical addresses, i.e. the
3734 MMU is not used either for address mapping nor for memory protection.
3736 The available memory is mapped to fixed addresses using the memory
3737 controller. In this process, a contiguous block is formed for each
3738 memory type (Flash, SDRAM, SRAM), even when it consists of several
3739 physical memory banks.
3741 U-Boot is installed in the first 128 kB of the first Flash bank (on
3742 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3743 booting and sizing and initializing DRAM, the code relocates itself
3744 to the upper end of DRAM. Immediately below the U-Boot code some
3745 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3746 configuration setting]. Below that, a structure with global Board
3747 Info data is placed, followed by the stack (growing downward).
3749 Additionally, some exception handler code is copied to the low 8 kB
3750 of DRAM (0x00000000 ... 0x00001FFF).
3752 So a typical memory configuration with 16 MB of DRAM could look like
3755 0x0000 0000 Exception Vector code
3758 0x0000 2000 Free for Application Use
3764 0x00FB FF20 Monitor Stack (Growing downward)
3765 0x00FB FFAC Board Info Data and permanent copy of global data
3766 0x00FC 0000 Malloc Arena
3769 0x00FE 0000 RAM Copy of Monitor Code
3770 ... eventually: LCD or video framebuffer
3771 ... eventually: pRAM (Protected RAM - unchanged by reset)
3772 0x00FF FFFF [End of RAM]
3775 System Initialization:
3776 ----------------------
3778 In the reset configuration, U-Boot starts at the reset entry point
3779 (on most PowerPC systems at address 0x00000100). Because of the reset
3780 configuration for CS0# this is a mirror of the onboard Flash memory.
3781 To be able to re-map memory U-Boot then jumps to its link address.
3782 To be able to implement the initialization code in C, a (small!)
3783 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3784 which provide such a feature like MPC8xx or MPC8260), or in a locked
3785 part of the data cache. After that, U-Boot initializes the CPU core,
3786 the caches and the SIU.
3788 Next, all (potentially) available memory banks are mapped using a
3789 preliminary mapping. For example, we put them on 512 MB boundaries
3790 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3791 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3792 programmed for SDRAM access. Using the temporary configuration, a
3793 simple memory test is run that determines the size of the SDRAM
3796 When there is more than one SDRAM bank, and the banks are of
3797 different size, the largest is mapped first. For equal size, the first
3798 bank (CS2#) is mapped first. The first mapping is always for address
3799 0x00000000, with any additional banks following immediately to create
3800 contiguous memory starting from 0.
3802 Then, the monitor installs itself at the upper end of the SDRAM area
3803 and allocates memory for use by malloc() and for the global Board
3804 Info data; also, the exception vector code is copied to the low RAM
3805 pages, and the final stack is set up.
3807 Only after this relocation will you have a "normal" C environment;
3808 until that you are restricted in several ways, mostly because you are
3809 running from ROM, and because the code will have to be relocated to a
3813 U-Boot Porting Guide:
3814 ----------------------
3816 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3820 int main (int argc, char *argv[])
3822 sighandler_t no_more_time;
3824 signal (SIGALRM, no_more_time);
3825 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3827 if (available_money > available_manpower) {
3828 pay consultant to port U-Boot;
3832 Download latest U-Boot source;
3834 Subscribe to u-boot-users mailing list;
3837 email ("Hi, I am new to U-Boot, how do I get started?");
3841 Read the README file in the top level directory;
3842 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3843 Read the source, Luke;
3846 if (available_money > toLocalCurrency ($2500)) {
3849 Add a lot of aggravation and time;
3852 Create your own board support subdirectory;
3854 Create your own board config file;
3858 Add / modify source code;
3862 email ("Hi, I am having problems...");
3864 Send patch file to Wolfgang;
3869 void no_more_time (int sig)
3878 All contributions to U-Boot should conform to the Linux kernel
3879 coding style; see the file "Documentation/CodingStyle" and the script
3880 "scripts/Lindent" in your Linux kernel source directory. In sources
3881 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3882 spaces before parameters to function calls) is actually used.
3884 Source files originating from a different project (for example the
3885 MTD subsystem) are generally exempt from these guidelines and are not
3886 reformated to ease subsequent migration to newer versions of those
3889 Please note that U-Boot is implemented in C (and to some small parts in
3890 Assembler); no C++ is used, so please do not use C++ style comments (//)
3893 Please also stick to the following formatting rules:
3894 - remove any trailing white space
3895 - use TAB characters for indentation, not spaces
3896 - make sure NOT to use DOS '\r\n' line feeds
3897 - do not add more than 2 empty lines to source files
3898 - do not add trailing empty lines to source files
3900 Submissions which do not conform to the standards may be returned
3901 with a request to reformat the changes.
3907 Since the number of patches for U-Boot is growing, we need to
3908 establish some rules. Submissions which do not conform to these rules
3909 may be rejected, even when they contain important and valuable stuff.
3911 Patches shall be sent to the u-boot-users mailing list.
3913 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
3915 When you send a patch, please include the following information with
3918 * For bug fixes: a description of the bug and how your patch fixes
3919 this bug. Please try to include a way of demonstrating that the
3920 patch actually fixes something.
3922 * For new features: a description of the feature and your
3925 * A CHANGELOG entry as plaintext (separate from the patch)
3927 * For major contributions, your entry to the CREDITS file
3929 * When you add support for a new board, don't forget to add this
3930 board to the MAKEALL script, too.
3932 * If your patch adds new configuration options, don't forget to
3933 document these in the README file.
3935 * The patch itself. If you are using git (which is *strongly*
3936 recommended) you can easily generate the patch using the
3937 "git-format-patch". If you then use "git-send-email" to send it to
3938 the U-Boot mailing list, you will avoid most of the common problems
3939 with some other mail clients.
3941 If you cannot use git, use "diff -purN OLD NEW". If your version of
3942 diff does not support these options, then get the latest version of
3945 The current directory when running this command shall be the parent
3946 directory of the U-Boot source tree (i. e. please make sure that
3947 your patch includes sufficient directory information for the
3950 We prefer patches as plain text. MIME attachments are discouraged,
3951 and compressed attachments must not be used.
3953 * If one logical set of modifications affects or creates several
3954 files, all these changes shall be submitted in a SINGLE patch file.
3956 * Changesets that contain different, unrelated modifications shall be
3957 submitted as SEPARATE patches, one patch per changeset.
3962 * Before sending the patch, run the MAKEALL script on your patched
3963 source tree and make sure that no errors or warnings are reported
3964 for any of the boards.
3966 * Keep your modifications to the necessary minimum: A patch
3967 containing several unrelated changes or arbitrary reformats will be
3968 returned with a request to re-formatting / split it.
3970 * If you modify existing code, make sure that your new code does not
3971 add to the memory footprint of the code ;-) Small is beautiful!
3972 When adding new features, these should compile conditionally only
3973 (using #ifdef), and the resulting code with the new feature
3974 disabled must not need more memory than the old code without your
3977 * Remember that there is a size limit of 40 kB per message on the
3978 u-boot-users mailing list. Bigger patches will be moderated. If
3979 they are reasonable and not bigger than 100 kB, they will be
3980 acknowledged. Even bigger patches should be avoided.
projects / kernel / u-boot.git / blob