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@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 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
1049 If this option is set, support for lzma compressed
1052 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1053 requires an amount of dynamic memory that is given by the
1056 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1058 Where lc and lp stand for, respectively, Literal context bits
1059 and Literal pos bits.
1061 This value is upper-bounded by 14MB in the worst case. Anyway,
1062 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1063 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1064 a very small buffer.
1066 Use the lzmainfo tool to determinate the lc and lp values and
1067 then calculate the amount of needed dynamic memory (ensuring
1068 the appropriate CFG_MALLOC_LEN value).
1073 The address of PHY on MII bus.
1075 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1077 The clock frequency of the MII bus
1081 If this option is set, support for speed/duplex
1082 detection of gigabit PHY is included.
1084 CONFIG_PHY_RESET_DELAY
1086 Some PHY like Intel LXT971A need extra delay after
1087 reset before any MII register access is possible.
1088 For such PHY, set this option to the usec delay
1089 required. (minimum 300usec for LXT971A)
1091 CONFIG_PHY_CMD_DELAY (ppc4xx)
1093 Some PHY like Intel LXT971A need extra delay after
1094 command issued before MII status register can be read
1104 Define a default value for Ethernet address to use
1105 for the respective Ethernet interface, in case this
1106 is not determined automatically.
1111 Define a default value for the IP address to use for
1112 the default Ethernet interface, in case this is not
1113 determined through e.g. bootp.
1115 - Server IP address:
1118 Defines a default value for the IP address of a TFTP
1119 server to contact when using the "tftboot" command.
1121 - Multicast TFTP Mode:
1124 Defines whether you want to support multicast TFTP as per
1125 rfc-2090; for example to work with atftp. Lets lots of targets
1126 tftp down the same boot image concurrently. Note: the Ethernet
1127 driver in use must provide a function: mcast() to join/leave a
1130 CONFIG_BOOTP_RANDOM_DELAY
1131 - BOOTP Recovery Mode:
1132 CONFIG_BOOTP_RANDOM_DELAY
1134 If you have many targets in a network that try to
1135 boot using BOOTP, you may want to avoid that all
1136 systems send out BOOTP requests at precisely the same
1137 moment (which would happen for instance at recovery
1138 from a power failure, when all systems will try to
1139 boot, thus flooding the BOOTP server. Defining
1140 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1141 inserted before sending out BOOTP requests. The
1142 following delays are inserted then:
1144 1st BOOTP request: delay 0 ... 1 sec
1145 2nd BOOTP request: delay 0 ... 2 sec
1146 3rd BOOTP request: delay 0 ... 4 sec
1148 BOOTP requests: delay 0 ... 8 sec
1150 - DHCP Advanced Options:
1151 You can fine tune the DHCP functionality by defining
1152 CONFIG_BOOTP_* symbols:
1154 CONFIG_BOOTP_SUBNETMASK
1155 CONFIG_BOOTP_GATEWAY
1156 CONFIG_BOOTP_HOSTNAME
1157 CONFIG_BOOTP_NISDOMAIN
1158 CONFIG_BOOTP_BOOTPATH
1159 CONFIG_BOOTP_BOOTFILESIZE
1162 CONFIG_BOOTP_SEND_HOSTNAME
1163 CONFIG_BOOTP_NTPSERVER
1164 CONFIG_BOOTP_TIMEOFFSET
1165 CONFIG_BOOTP_VENDOREX
1167 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1168 environment variable, not the BOOTP server.
1170 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1171 serverip from a DHCP server, it is possible that more
1172 than one DNS serverip is offered to the client.
1173 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1174 serverip will be stored in the additional environment
1175 variable "dnsip2". The first DNS serverip is always
1176 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1179 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1180 to do a dynamic update of a DNS server. To do this, they
1181 need the hostname of the DHCP requester.
1182 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1183 of the "hostname" environment variable is passed as
1184 option 12 to the DHCP server.
1186 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1188 A 32bit value in microseconds for a delay between
1189 receiving a "DHCP Offer" and sending the "DHCP Request".
1190 This fixes a problem with certain DHCP servers that don't
1191 respond 100% of the time to a "DHCP request". E.g. On an
1192 AT91RM9200 processor running at 180MHz, this delay needed
1193 to be *at least* 15,000 usec before a Windows Server 2003
1194 DHCP server would reply 100% of the time. I recommend at
1195 least 50,000 usec to be safe. The alternative is to hope
1196 that one of the retries will be successful but note that
1197 the DHCP timeout and retry process takes a longer than
1201 CONFIG_CDP_DEVICE_ID
1203 The device id used in CDP trigger frames.
1205 CONFIG_CDP_DEVICE_ID_PREFIX
1207 A two character string which is prefixed to the MAC address
1212 A printf format string which contains the ascii name of
1213 the port. Normally is set to "eth%d" which sets
1214 eth0 for the first Ethernet, eth1 for the second etc.
1216 CONFIG_CDP_CAPABILITIES
1218 A 32bit integer which indicates the device capabilities;
1219 0x00000010 for a normal host which does not forwards.
1223 An ascii string containing the version of the software.
1227 An ascii string containing the name of the platform.
1231 A 32bit integer sent on the trigger.
1233 CONFIG_CDP_POWER_CONSUMPTION
1235 A 16bit integer containing the power consumption of the
1236 device in .1 of milliwatts.
1238 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1240 A byte containing the id of the VLAN.
1242 - Status LED: CONFIG_STATUS_LED
1244 Several configurations allow to display the current
1245 status using a LED. For instance, the LED will blink
1246 fast while running U-Boot code, stop blinking as
1247 soon as a reply to a BOOTP request was received, and
1248 start blinking slow once the Linux kernel is running
1249 (supported by a status LED driver in the Linux
1250 kernel). Defining CONFIG_STATUS_LED enables this
1253 - CAN Support: CONFIG_CAN_DRIVER
1255 Defining CONFIG_CAN_DRIVER enables CAN driver support
1256 on those systems that support this (optional)
1257 feature, like the TQM8xxL modules.
1259 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1261 These enable I2C serial bus commands. Defining either of
1262 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1263 include the appropriate I2C driver for the selected CPU.
1265 This will allow you to use i2c commands at the u-boot
1266 command line (as long as you set CONFIG_CMD_I2C in
1267 CONFIG_COMMANDS) and communicate with i2c based realtime
1268 clock chips. See common/cmd_i2c.c for a description of the
1269 command line interface.
1271 CONFIG_I2C_CMD_TREE is a recommended option that places
1272 all I2C commands under a single 'i2c' root command. The
1273 older 'imm', 'imd', 'iprobe' etc. commands are considered
1274 deprecated and may disappear in the future.
1276 CONFIG_HARD_I2C selects a hardware I2C controller.
1278 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1279 bit-banging) driver instead of CPM or similar hardware
1282 There are several other quantities that must also be
1283 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1285 In both cases you will need to define CFG_I2C_SPEED
1286 to be the frequency (in Hz) at which you wish your i2c bus
1287 to run and CFG_I2C_SLAVE to be the address of this node (ie
1288 the CPU's i2c node address).
1290 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1291 sets the CPU up as a master node and so its address should
1292 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1293 p.16-473). So, set CFG_I2C_SLAVE to 0.
1295 That's all that's required for CONFIG_HARD_I2C.
1297 If you use the software i2c interface (CONFIG_SOFT_I2C)
1298 then the following macros need to be defined (examples are
1299 from include/configs/lwmon.h):
1303 (Optional). Any commands necessary to enable the I2C
1304 controller or configure ports.
1306 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1310 (Only for MPC8260 CPU). The I/O port to use (the code
1311 assumes both bits are on the same port). Valid values
1312 are 0..3 for ports A..D.
1316 The code necessary to make the I2C data line active
1317 (driven). If the data line is open collector, this
1320 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1324 The code necessary to make the I2C data line tri-stated
1325 (inactive). If the data line is open collector, this
1328 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1332 Code that returns TRUE if the I2C data line is high,
1335 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1339 If <bit> is TRUE, sets the I2C data line high. If it
1340 is FALSE, it clears it (low).
1342 eg: #define I2C_SDA(bit) \
1343 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1344 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1348 If <bit> is TRUE, sets the I2C clock line high. If it
1349 is FALSE, it clears it (low).
1351 eg: #define I2C_SCL(bit) \
1352 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1353 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1357 This delay is invoked four times per clock cycle so this
1358 controls the rate of data transfer. The data rate thus
1359 is 1 / (I2C_DELAY * 4). Often defined to be something
1362 #define I2C_DELAY udelay(2)
1366 When a board is reset during an i2c bus transfer
1367 chips might think that the current transfer is still
1368 in progress. On some boards it is possible to access
1369 the i2c SCLK line directly, either by using the
1370 processor pin as a GPIO or by having a second pin
1371 connected to the bus. If this option is defined a
1372 custom i2c_init_board() routine in boards/xxx/board.c
1373 is run early in the boot sequence.
1375 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1377 This option enables configuration of bi_iic_fast[] flags
1378 in u-boot bd_info structure based on u-boot environment
1379 variable "i2cfast". (see also i2cfast)
1381 CONFIG_I2C_MULTI_BUS
1383 This option allows the use of multiple I2C buses, each of which
1384 must have a controller. At any point in time, only one bus is
1385 active. To switch to a different bus, use the 'i2c dev' command.
1386 Note that bus numbering is zero-based.
1390 This option specifies a list of I2C devices that will be skipped
1391 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1392 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1393 pairs. Otherwise, specify a 1D array of device addresses
1396 #undef CONFIG_I2C_MULTI_BUS
1397 #define CFG_I2C_NOPROBES {0x50,0x68}
1399 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1401 #define CONFIG_I2C_MULTI_BUS
1402 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1404 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1408 If defined, then this indicates the I2C bus number for DDR SPD.
1409 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1413 If defined, then this indicates the I2C bus number for the RTC.
1414 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1418 If defined, then this indicates the I2C bus number for the DTT.
1419 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1423 If defined, specifies the I2C address of the DTT device.
1424 If not defined, then U-Boot uses predefined value for
1425 specified DTT device.
1429 Define this option if you want to use Freescale's I2C driver in
1430 drivers/i2c/fsl_i2c.c.
1433 - SPI Support: CONFIG_SPI
1435 Enables SPI driver (so far only tested with
1436 SPI EEPROM, also an instance works with Crystal A/D and
1437 D/As on the SACSng board)
1441 Enables extended (16-bit) SPI EEPROM addressing.
1442 (symmetrical to CONFIG_I2C_X)
1446 Enables a software (bit-bang) SPI driver rather than
1447 using hardware support. This is a general purpose
1448 driver that only requires three general I/O port pins
1449 (two outputs, one input) to function. If this is
1450 defined, the board configuration must define several
1451 SPI configuration items (port pins to use, etc). For
1452 an example, see include/configs/sacsng.h.
1456 Enables a hardware SPI driver for general-purpose reads
1457 and writes. As with CONFIG_SOFT_SPI, the board configuration
1458 must define a list of chip-select function pointers.
1459 Currently supported on some MPC8xxx processors. For an
1460 example, see include/configs/mpc8349emds.h.
1464 Enables the driver for the SPI controllers on i.MX and MXC
1465 SoCs. Currently only i.MX31 is supported.
1467 - FPGA Support: CONFIG_FPGA
1469 Enables FPGA subsystem.
1471 CONFIG_FPGA_<vendor>
1473 Enables support for specific chip vendors.
1476 CONFIG_FPGA_<family>
1478 Enables support for FPGA family.
1479 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1483 Specify the number of FPGA devices to support.
1485 CFG_FPGA_PROG_FEEDBACK
1487 Enable printing of hash marks during FPGA configuration.
1491 Enable checks on FPGA configuration interface busy
1492 status by the configuration function. This option
1493 will require a board or device specific function to
1498 If defined, a function that provides delays in the FPGA
1499 configuration driver.
1501 CFG_FPGA_CHECK_CTRLC
1502 Allow Control-C to interrupt FPGA configuration
1504 CFG_FPGA_CHECK_ERROR
1506 Check for configuration errors during FPGA bitfile
1507 loading. For example, abort during Virtex II
1508 configuration if the INIT_B line goes low (which
1509 indicated a CRC error).
1513 Maximum time to wait for the INIT_B line to deassert
1514 after PROB_B has been deasserted during a Virtex II
1515 FPGA configuration sequence. The default time is 500
1520 Maximum time to wait for BUSY to deassert during
1521 Virtex II FPGA configuration. The default is 5 ms.
1523 CFG_FPGA_WAIT_CONFIG
1525 Time to wait after FPGA configuration. The default is
1528 - Configuration Management:
1531 If defined, this string will be added to the U-Boot
1532 version information (U_BOOT_VERSION)
1534 - Vendor Parameter Protection:
1536 U-Boot considers the values of the environment
1537 variables "serial#" (Board Serial Number) and
1538 "ethaddr" (Ethernet Address) to be parameters that
1539 are set once by the board vendor / manufacturer, and
1540 protects these variables from casual modification by
1541 the user. Once set, these variables are read-only,
1542 and write or delete attempts are rejected. You can
1543 change this behaviour:
1545 If CONFIG_ENV_OVERWRITE is #defined in your config
1546 file, the write protection for vendor parameters is
1547 completely disabled. Anybody can change or delete
1550 Alternatively, if you #define _both_ CONFIG_ETHADDR
1551 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1552 Ethernet address is installed in the environment,
1553 which can be changed exactly ONCE by the user. [The
1554 serial# is unaffected by this, i. e. it remains
1560 Define this variable to enable the reservation of
1561 "protected RAM", i. e. RAM which is not overwritten
1562 by U-Boot. Define CONFIG_PRAM to hold the number of
1563 kB you want to reserve for pRAM. You can overwrite
1564 this default value by defining an environment
1565 variable "pram" to the number of kB you want to
1566 reserve. Note that the board info structure will
1567 still show the full amount of RAM. If pRAM is
1568 reserved, a new environment variable "mem" will
1569 automatically be defined to hold the amount of
1570 remaining RAM in a form that can be passed as boot
1571 argument to Linux, for instance like that:
1573 setenv bootargs ... mem=\${mem}
1576 This way you can tell Linux not to use this memory,
1577 either, which results in a memory region that will
1578 not be affected by reboots.
1580 *WARNING* If your board configuration uses automatic
1581 detection of the RAM size, you must make sure that
1582 this memory test is non-destructive. So far, the
1583 following board configurations are known to be
1586 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1587 HERMES, IP860, RPXlite, LWMON, LANTEC,
1588 PCU_E, FLAGADM, TQM8260
1593 Define this variable to stop the system in case of a
1594 fatal error, so that you have to reset it manually.
1595 This is probably NOT a good idea for an embedded
1596 system where you want the system to reboot
1597 automatically as fast as possible, but it may be
1598 useful during development since you can try to debug
1599 the conditions that lead to the situation.
1601 CONFIG_NET_RETRY_COUNT
1603 This variable defines the number of retries for
1604 network operations like ARP, RARP, TFTP, or BOOTP
1605 before giving up the operation. If not defined, a
1606 default value of 5 is used.
1610 Timeout waiting for an ARP reply in milliseconds.
1612 - Command Interpreter:
1613 CONFIG_AUTO_COMPLETE
1615 Enable auto completion of commands using TAB.
1617 Note that this feature has NOT been implemented yet
1618 for the "hush" shell.
1623 Define this variable to enable the "hush" shell (from
1624 Busybox) as command line interpreter, thus enabling
1625 powerful command line syntax like
1626 if...then...else...fi conditionals or `&&' and '||'
1627 constructs ("shell scripts").
1629 If undefined, you get the old, much simpler behaviour
1630 with a somewhat smaller memory footprint.
1635 This defines the secondary prompt string, which is
1636 printed when the command interpreter needs more input
1637 to complete a command. Usually "> ".
1641 In the current implementation, the local variables
1642 space and global environment variables space are
1643 separated. Local variables are those you define by
1644 simply typing `name=value'. To access a local
1645 variable later on, you have write `$name' or
1646 `${name}'; to execute the contents of a variable
1647 directly type `$name' at the command prompt.
1649 Global environment variables are those you use
1650 setenv/printenv to work with. To run a command stored
1651 in such a variable, you need to use the run command,
1652 and you must not use the '$' sign to access them.
1654 To store commands and special characters in a
1655 variable, please use double quotation marks
1656 surrounding the whole text of the variable, instead
1657 of the backslashes before semicolons and special
1660 - Commandline Editing and History:
1661 CONFIG_CMDLINE_EDITING
1663 Enable editing and History functions for interactive
1664 commandline input operations
1666 - Default Environment:
1667 CONFIG_EXTRA_ENV_SETTINGS
1669 Define this to contain any number of null terminated
1670 strings (variable = value pairs) that will be part of
1671 the default environment compiled into the boot image.
1673 For example, place something like this in your
1674 board's config file:
1676 #define CONFIG_EXTRA_ENV_SETTINGS \
1680 Warning: This method is based on knowledge about the
1681 internal format how the environment is stored by the
1682 U-Boot code. This is NOT an official, exported
1683 interface! Although it is unlikely that this format
1684 will change soon, there is no guarantee either.
1685 You better know what you are doing here.
1687 Note: overly (ab)use of the default environment is
1688 discouraged. Make sure to check other ways to preset
1689 the environment like the autoscript function or the
1692 - DataFlash Support:
1693 CONFIG_HAS_DATAFLASH
1695 Defining this option enables DataFlash features and
1696 allows to read/write in Dataflash via the standard
1699 - SystemACE Support:
1702 Adding this option adds support for Xilinx SystemACE
1703 chips attached via some sort of local bus. The address
1704 of the chip must also be defined in the
1705 CFG_SYSTEMACE_BASE macro. For example:
1707 #define CONFIG_SYSTEMACE
1708 #define CFG_SYSTEMACE_BASE 0xf0000000
1710 When SystemACE support is added, the "ace" device type
1711 becomes available to the fat commands, i.e. fatls.
1713 - TFTP Fixed UDP Port:
1716 If this is defined, the environment variable tftpsrcp
1717 is used to supply the TFTP UDP source port value.
1718 If tftpsrcp isn't defined, the normal pseudo-random port
1719 number generator is used.
1721 Also, the environment variable tftpdstp is used to supply
1722 the TFTP UDP destination port value. If tftpdstp isn't
1723 defined, the normal port 69 is used.
1725 The purpose for tftpsrcp is to allow a TFTP server to
1726 blindly start the TFTP transfer using the pre-configured
1727 target IP address and UDP port. This has the effect of
1728 "punching through" the (Windows XP) firewall, allowing
1729 the remainder of the TFTP transfer to proceed normally.
1730 A better solution is to properly configure the firewall,
1731 but sometimes that is not allowed.
1733 - Show boot progress:
1734 CONFIG_SHOW_BOOT_PROGRESS
1736 Defining this option allows to add some board-
1737 specific code (calling a user-provided function
1738 "show_boot_progress(int)") that enables you to show
1739 the system's boot progress on some display (for
1740 example, some LED's) on your board. At the moment,
1741 the following checkpoints are implemented:
1743 Legacy uImage format:
1746 1 common/cmd_bootm.c before attempting to boot an image
1747 -1 common/cmd_bootm.c Image header has bad magic number
1748 2 common/cmd_bootm.c Image header has correct magic number
1749 -2 common/cmd_bootm.c Image header has bad checksum
1750 3 common/cmd_bootm.c Image header has correct checksum
1751 -3 common/cmd_bootm.c Image data has bad checksum
1752 4 common/cmd_bootm.c Image data has correct checksum
1753 -4 common/cmd_bootm.c Image is for unsupported architecture
1754 5 common/cmd_bootm.c Architecture check OK
1755 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1756 6 common/cmd_bootm.c Image Type check OK
1757 -6 common/cmd_bootm.c gunzip uncompression error
1758 -7 common/cmd_bootm.c Unimplemented compression type
1759 7 common/cmd_bootm.c Uncompression OK
1760 8 common/cmd_bootm.c No uncompress/copy overwrite error
1761 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1763 9 common/image.c Start initial ramdisk verification
1764 -10 common/image.c Ramdisk header has bad magic number
1765 -11 common/image.c Ramdisk header has bad checksum
1766 10 common/image.c Ramdisk header is OK
1767 -12 common/image.c Ramdisk data has bad checksum
1768 11 common/image.c Ramdisk data has correct checksum
1769 12 common/image.c Ramdisk verification complete, start loading
1770 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1771 13 common/image.c Start multifile image verification
1772 14 common/image.c No initial ramdisk, no multifile, continue.
1774 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1776 -30 lib_ppc/board.c Fatal error, hang the system
1777 -31 post/post.c POST test failed, detected by post_output_backlog()
1778 -32 post/post.c POST test failed, detected by post_run_single()
1780 34 common/cmd_doc.c before loading a Image from a DOC device
1781 -35 common/cmd_doc.c Bad usage of "doc" command
1782 35 common/cmd_doc.c correct usage of "doc" command
1783 -36 common/cmd_doc.c No boot device
1784 36 common/cmd_doc.c correct boot device
1785 -37 common/cmd_doc.c Unknown Chip ID on boot device
1786 37 common/cmd_doc.c correct chip ID found, device available
1787 -38 common/cmd_doc.c Read Error on boot device
1788 38 common/cmd_doc.c reading Image header from DOC device OK
1789 -39 common/cmd_doc.c Image header has bad magic number
1790 39 common/cmd_doc.c Image header has correct magic number
1791 -40 common/cmd_doc.c Error reading Image from DOC device
1792 40 common/cmd_doc.c Image header has correct magic number
1793 41 common/cmd_ide.c before loading a Image from a IDE device
1794 -42 common/cmd_ide.c Bad usage of "ide" command
1795 42 common/cmd_ide.c correct usage of "ide" command
1796 -43 common/cmd_ide.c No boot device
1797 43 common/cmd_ide.c boot device found
1798 -44 common/cmd_ide.c Device not available
1799 44 common/cmd_ide.c Device available
1800 -45 common/cmd_ide.c wrong partition selected
1801 45 common/cmd_ide.c partition selected
1802 -46 common/cmd_ide.c Unknown partition table
1803 46 common/cmd_ide.c valid partition table found
1804 -47 common/cmd_ide.c Invalid partition type
1805 47 common/cmd_ide.c correct partition type
1806 -48 common/cmd_ide.c Error reading Image Header on boot device
1807 48 common/cmd_ide.c reading Image Header from IDE device OK
1808 -49 common/cmd_ide.c Image header has bad magic number
1809 49 common/cmd_ide.c Image header has correct magic number
1810 -50 common/cmd_ide.c Image header has bad checksum
1811 50 common/cmd_ide.c Image header has correct checksum
1812 -51 common/cmd_ide.c Error reading Image from IDE device
1813 51 common/cmd_ide.c reading Image from IDE device OK
1814 52 common/cmd_nand.c before loading a Image from a NAND device
1815 -53 common/cmd_nand.c Bad usage of "nand" command
1816 53 common/cmd_nand.c correct usage of "nand" command
1817 -54 common/cmd_nand.c No boot device
1818 54 common/cmd_nand.c boot device found
1819 -55 common/cmd_nand.c Unknown Chip ID on boot device
1820 55 common/cmd_nand.c correct chip ID found, device available
1821 -56 common/cmd_nand.c Error reading Image Header on boot device
1822 56 common/cmd_nand.c reading Image Header from NAND device OK
1823 -57 common/cmd_nand.c Image header has bad magic number
1824 57 common/cmd_nand.c Image header has correct magic number
1825 -58 common/cmd_nand.c Error reading Image from NAND device
1826 58 common/cmd_nand.c reading Image from NAND device OK
1828 -60 common/env_common.c Environment has a bad CRC, using default
1830 64 net/eth.c starting with Ethernet configuration.
1831 -64 net/eth.c no Ethernet found.
1832 65 net/eth.c Ethernet found.
1834 -80 common/cmd_net.c usage wrong
1835 80 common/cmd_net.c before calling NetLoop()
1836 -81 common/cmd_net.c some error in NetLoop() occurred
1837 81 common/cmd_net.c NetLoop() back without error
1838 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1839 82 common/cmd_net.c trying automatic boot
1840 83 common/cmd_net.c running autoscript
1841 -83 common/cmd_net.c some error in automatic boot or autoscript
1842 84 common/cmd_net.c end without errors
1847 100 common/cmd_bootm.c Kernel FIT Image has correct format
1848 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1849 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1850 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1851 102 common/cmd_bootm.c Kernel unit name specified
1852 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1853 103 common/cmd_bootm.c Found configuration node
1854 104 common/cmd_bootm.c Got kernel subimage node offset
1855 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1856 105 common/cmd_bootm.c Kernel subimage hash verification OK
1857 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1858 106 common/cmd_bootm.c Architecture check OK
1859 -106 common/cmd_bootm.c Kernel subimage has wrong type
1860 107 common/cmd_bootm.c Kernel subimage type OK
1861 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1862 108 common/cmd_bootm.c Got kernel subimage data/size
1863 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1864 -109 common/cmd_bootm.c Can't get kernel subimage type
1865 -110 common/cmd_bootm.c Can't get kernel subimage comp
1866 -111 common/cmd_bootm.c Can't get kernel subimage os
1867 -112 common/cmd_bootm.c Can't get kernel subimage load address
1868 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1870 120 common/image.c Start initial ramdisk verification
1871 -120 common/image.c Ramdisk FIT image has incorrect format
1872 121 common/image.c Ramdisk FIT image has correct format
1873 122 common/image.c No ramdisk subimage unit name, using configuration
1874 -122 common/image.c Can't get configuration for ramdisk subimage
1875 123 common/image.c Ramdisk unit name specified
1876 -124 common/image.c Can't get ramdisk subimage node offset
1877 125 common/image.c Got ramdisk subimage node offset
1878 -125 common/image.c Ramdisk subimage hash verification failed
1879 126 common/image.c Ramdisk subimage hash verification OK
1880 -126 common/image.c Ramdisk subimage for unsupported architecture
1881 127 common/image.c Architecture check OK
1882 -127 common/image.c Can't get ramdisk subimage data/size
1883 128 common/image.c Got ramdisk subimage data/size
1884 129 common/image.c Can't get ramdisk load address
1885 -129 common/image.c Got ramdisk load address
1887 -130 common/cmd_doc.c Incorrect FIT image format
1888 131 common/cmd_doc.c FIT image format OK
1890 -140 common/cmd_ide.c Incorrect FIT image format
1891 141 common/cmd_ide.c FIT image format OK
1893 -150 common/cmd_nand.c Incorrect FIT image format
1894 151 common/cmd_nand.c FIT image format OK
1900 [so far only for SMDK2400 and TRAB boards]
1902 - Modem support enable:
1903 CONFIG_MODEM_SUPPORT
1905 - RTS/CTS Flow control enable:
1908 - Modem debug support:
1909 CONFIG_MODEM_SUPPORT_DEBUG
1911 Enables debugging stuff (char screen[1024], dbg())
1912 for modem support. Useful only with BDI2000.
1914 - Interrupt support (PPC):
1916 There are common interrupt_init() and timer_interrupt()
1917 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1918 for CPU specific initialization. interrupt_init_cpu()
1919 should set decrementer_count to appropriate value. If
1920 CPU resets decrementer automatically after interrupt
1921 (ppc4xx) it should set decrementer_count to zero.
1922 timer_interrupt() calls timer_interrupt_cpu() for CPU
1923 specific handling. If board has watchdog / status_led
1924 / other_activity_monitor it works automatically from
1925 general timer_interrupt().
1929 In the target system modem support is enabled when a
1930 specific key (key combination) is pressed during
1931 power-on. Otherwise U-Boot will boot normally
1932 (autoboot). The key_pressed() function is called from
1933 board_init(). Currently key_pressed() is a dummy
1934 function, returning 1 and thus enabling modem
1937 If there are no modem init strings in the
1938 environment, U-Boot proceed to autoboot; the
1939 previous output (banner, info printfs) will be
1942 See also: doc/README.Modem
1945 Configuration Settings:
1946 -----------------------
1948 - CFG_LONGHELP: Defined when you want long help messages included;
1949 undefine this when you're short of memory.
1951 - CFG_PROMPT: This is what U-Boot prints on the console to
1952 prompt for user input.
1954 - CFG_CBSIZE: Buffer size for input from the Console
1956 - CFG_PBSIZE: Buffer size for Console output
1958 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1960 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1961 the application (usually a Linux kernel) when it is
1964 - CFG_BAUDRATE_TABLE:
1965 List of legal baudrate settings for this board.
1967 - CFG_CONSOLE_INFO_QUIET
1968 Suppress display of console information at boot.
1970 - CFG_CONSOLE_IS_IN_ENV
1971 If the board specific function
1972 extern int overwrite_console (void);
1973 returns 1, the stdin, stderr and stdout are switched to the
1974 serial port, else the settings in the environment are used.
1976 - CFG_CONSOLE_OVERWRITE_ROUTINE
1977 Enable the call to overwrite_console().
1979 - CFG_CONSOLE_ENV_OVERWRITE
1980 Enable overwrite of previous console environment settings.
1982 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1983 Begin and End addresses of the area used by the
1987 Enable an alternate, more extensive memory test.
1989 - CFG_MEMTEST_SCRATCH:
1990 Scratch address used by the alternate memory test
1991 You only need to set this if address zero isn't writeable
1993 - CFG_MEM_TOP_HIDE (PPC only):
1994 If CFG_MEM_TOP_HIDE is defined in the board config header,
1995 this specified memory area will get subtracted from the top
1996 (end) of RAM and won't get "touched" at all by U-Boot. By
1997 fixing up gd->ram_size the Linux kernel should gets passed
1998 the now "corrected" memory size and won't touch it either.
1999 This should work for arch/ppc and arch/powerpc. Only Linux
2000 board ports in arch/powerpc with bootwrapper support that
2001 recalculate the memory size from the SDRAM controller setup
2002 will have to get fixed in Linux additionally.
2004 This option can be used as a workaround for the 440EPx/GRx
2005 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2008 WARNING: Please make sure that this value is a multiple of
2009 the Linux page size (normally 4k). If this is not the case,
2010 then the end address of the Linux memory will be located at a
2011 non page size aligned address and this could cause major
2014 - CFG_TFTP_LOADADDR:
2015 Default load address for network file downloads
2017 - CFG_LOADS_BAUD_CHANGE:
2018 Enable temporary baudrate change while serial download
2021 Physical start address of SDRAM. _Must_ be 0 here.
2024 Physical start address of Motherboard I/O (if using a
2028 Physical start address of Flash memory.
2031 Physical start address of boot monitor code (set by
2032 make config files to be same as the text base address
2033 (TEXT_BASE) used when linking) - same as
2034 CFG_FLASH_BASE when booting from flash.
2037 Size of memory reserved for monitor code, used to
2038 determine _at_compile_time_ (!) if the environment is
2039 embedded within the U-Boot image, or in a separate
2043 Size of DRAM reserved for malloc() use.
2046 Normally compressed uImages are limited to an
2047 uncompressed size of 8 MBytes. If this is not enough,
2048 you can define CFG_BOOTM_LEN in your board config file
2049 to adjust this setting to your needs.
2052 Maximum size of memory mapped by the startup code of
2053 the Linux kernel; all data that must be processed by
2054 the Linux kernel (bd_info, boot arguments, FDT blob if
2055 used) must be put below this limit, unless "bootm_low"
2056 enviroment variable is defined and non-zero. In such case
2057 all data for the Linux kernel must be between "bootm_low"
2058 and "bootm_low" + CFG_BOOTMAPSZ.
2060 - CFG_MAX_FLASH_BANKS:
2061 Max number of Flash memory banks
2063 - CFG_MAX_FLASH_SECT:
2064 Max number of sectors on a Flash chip
2066 - CFG_FLASH_ERASE_TOUT:
2067 Timeout for Flash erase operations (in ms)
2069 - CFG_FLASH_WRITE_TOUT:
2070 Timeout for Flash write operations (in ms)
2072 - CFG_FLASH_LOCK_TOUT
2073 Timeout for Flash set sector lock bit operation (in ms)
2075 - CFG_FLASH_UNLOCK_TOUT
2076 Timeout for Flash clear lock bits operation (in ms)
2078 - CFG_FLASH_PROTECTION
2079 If defined, hardware flash sectors protection is used
2080 instead of U-Boot software protection.
2082 - CFG_DIRECT_FLASH_TFTP:
2084 Enable TFTP transfers directly to flash memory;
2085 without this option such a download has to be
2086 performed in two steps: (1) download to RAM, and (2)
2087 copy from RAM to flash.
2089 The two-step approach is usually more reliable, since
2090 you can check if the download worked before you erase
2091 the flash, but in some situations (when system RAM is
2092 too limited to allow for a temporary copy of the
2093 downloaded image) this option may be very useful.
2096 Define if the flash driver uses extra elements in the
2097 common flash structure for storing flash geometry.
2099 - CONFIG_FLASH_CFI_DRIVER
2100 This option also enables the building of the cfi_flash driver
2101 in the drivers directory
2103 - CFG_FLASH_USE_BUFFER_WRITE
2104 Use buffered writes to flash.
2106 - CONFIG_FLASH_SPANSION_S29WS_N
2107 s29ws-n MirrorBit flash has non-standard addresses for buffered
2110 - CFG_FLASH_QUIET_TEST
2111 If this option is defined, the common CFI flash doesn't
2112 print it's warning upon not recognized FLASH banks. This
2113 is useful, if some of the configured banks are only
2114 optionally available.
2116 - CONFIG_FLASH_SHOW_PROGRESS
2117 If defined (must be an integer), print out countdown
2118 digits and dots. Recommended value: 45 (9..1) for 80
2119 column displays, 15 (3..1) for 40 column displays.
2121 - CFG_RX_ETH_BUFFER:
2122 Defines the number of Ethernet receive buffers. On some
2123 Ethernet controllers it is recommended to set this value
2124 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2125 buffers can be full shortly after enabling the interface
2126 on high Ethernet traffic.
2127 Defaults to 4 if not defined.
2129 The following definitions that deal with the placement and management
2130 of environment data (variable area); in general, we support the
2131 following configurations:
2133 - CONFIG_ENV_IS_IN_FLASH:
2135 Define this if the environment is in flash memory.
2137 a) The environment occupies one whole flash sector, which is
2138 "embedded" in the text segment with the U-Boot code. This
2139 happens usually with "bottom boot sector" or "top boot
2140 sector" type flash chips, which have several smaller
2141 sectors at the start or the end. For instance, such a
2142 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2143 such a case you would place the environment in one of the
2144 4 kB sectors - with U-Boot code before and after it. With
2145 "top boot sector" type flash chips, you would put the
2146 environment in one of the last sectors, leaving a gap
2147 between U-Boot and the environment.
2149 - CONFIG_ENV_OFFSET:
2151 Offset of environment data (variable area) to the
2152 beginning of flash memory; for instance, with bottom boot
2153 type flash chips the second sector can be used: the offset
2154 for this sector is given here.
2156 CONFIG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2160 This is just another way to specify the start address of
2161 the flash sector containing the environment (instead of
2164 - CONFIG_ENV_SECT_SIZE:
2166 Size of the sector containing the environment.
2169 b) Sometimes flash chips have few, equal sized, BIG sectors.
2170 In such a case you don't want to spend a whole sector for
2175 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2176 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2177 of this flash sector for the environment. This saves
2178 memory for the RAM copy of the environment.
2180 It may also save flash memory if you decide to use this
2181 when your environment is "embedded" within U-Boot code,
2182 since then the remainder of the flash sector could be used
2183 for U-Boot code. It should be pointed out that this is
2184 STRONGLY DISCOURAGED from a robustness point of view:
2185 updating the environment in flash makes it always
2186 necessary to erase the WHOLE sector. If something goes
2187 wrong before the contents has been restored from a copy in
2188 RAM, your target system will be dead.
2190 - CONFIG_ENV_ADDR_REDUND
2191 CONFIG_ENV_SIZE_REDUND
2193 These settings describe a second storage area used to hold
2194 a redundant copy of the environment data, so that there is
2195 a valid backup copy in case there is a power failure during
2196 a "saveenv" operation.
2198 BE CAREFUL! Any changes to the flash layout, and some changes to the
2199 source code will make it necessary to adapt <board>/u-boot.lds*
2203 - CONFIG_ENV_IS_IN_NVRAM:
2205 Define this if you have some non-volatile memory device
2206 (NVRAM, battery buffered SRAM) which you want to use for the
2212 These two #defines are used to determine the memory area you
2213 want to use for environment. It is assumed that this memory
2214 can just be read and written to, without any special
2217 BE CAREFUL! The first access to the environment happens quite early
2218 in U-Boot initalization (when we try to get the setting of for the
2219 console baudrate). You *MUST* have mapped your NVRAM area then, or
2222 Please note that even with NVRAM we still use a copy of the
2223 environment in RAM: we could work on NVRAM directly, but we want to
2224 keep settings there always unmodified except somebody uses "saveenv"
2225 to save the current settings.
2228 - CONFIG_ENV_IS_IN_EEPROM:
2230 Use this if you have an EEPROM or similar serial access
2231 device and a driver for it.
2233 - CONFIG_ENV_OFFSET:
2236 These two #defines specify the offset and size of the
2237 environment area within the total memory of your EEPROM.
2239 - CFG_I2C_EEPROM_ADDR:
2240 If defined, specified the chip address of the EEPROM device.
2241 The default address is zero.
2243 - CFG_EEPROM_PAGE_WRITE_BITS:
2244 If defined, the number of bits used to address bytes in a
2245 single page in the EEPROM device. A 64 byte page, for example
2246 would require six bits.
2248 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2249 If defined, the number of milliseconds to delay between
2250 page writes. The default is zero milliseconds.
2252 - CFG_I2C_EEPROM_ADDR_LEN:
2253 The length in bytes of the EEPROM memory array address. Note
2254 that this is NOT the chip address length!
2256 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2257 EEPROM chips that implement "address overflow" are ones
2258 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2259 address and the extra bits end up in the "chip address" bit
2260 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2263 Note that we consider the length of the address field to
2264 still be one byte because the extra address bits are hidden
2265 in the chip address.
2268 The size in bytes of the EEPROM device.
2271 - CONFIG_ENV_IS_IN_DATAFLASH:
2273 Define this if you have a DataFlash memory device which you
2274 want to use for the environment.
2276 - CONFIG_ENV_OFFSET:
2280 These three #defines specify the offset and size of the
2281 environment area within the total memory of your DataFlash placed
2282 at the specified address.
2284 - CONFIG_ENV_IS_IN_NAND:
2286 Define this if you have a NAND device which you want to use
2287 for the environment.
2289 - CONFIG_ENV_OFFSET:
2292 These two #defines specify the offset and size of the environment
2293 area within the first NAND device.
2295 - CONFIG_ENV_OFFSET_REDUND
2297 This setting describes a second storage area of CONFIG_ENV_SIZE
2298 size used to hold a redundant copy of the environment data,
2299 so that there is a valid backup copy in case there is a
2300 power failure during a "saveenv" operation.
2302 Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
2303 to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
2304 the NAND devices block size.
2306 - CFG_SPI_INIT_OFFSET
2308 Defines offset to the initial SPI buffer area in DPRAM. The
2309 area is used at an early stage (ROM part) if the environment
2310 is configured to reside in the SPI EEPROM: We need a 520 byte
2311 scratch DPRAM area. It is used between the two initialization
2312 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2313 to be a good choice since it makes it far enough from the
2314 start of the data area as well as from the stack pointer.
2316 Please note that the environment is read-only until the monitor
2317 has been relocated to RAM and a RAM copy of the environment has been
2318 created; also, when using EEPROM you will have to use getenv_r()
2319 until then to read environment variables.
2321 The environment is protected by a CRC32 checksum. Before the monitor
2322 is relocated into RAM, as a result of a bad CRC you will be working
2323 with the compiled-in default environment - *silently*!!! [This is
2324 necessary, because the first environment variable we need is the
2325 "baudrate" setting for the console - if we have a bad CRC, we don't
2326 have any device yet where we could complain.]
2328 Note: once the monitor has been relocated, then it will complain if
2329 the default environment is used; a new CRC is computed as soon as you
2330 use the "saveenv" command to store a valid environment.
2332 - CFG_FAULT_ECHO_LINK_DOWN:
2333 Echo the inverted Ethernet link state to the fault LED.
2335 Note: If this option is active, then CFG_FAULT_MII_ADDR
2336 also needs to be defined.
2338 - CFG_FAULT_MII_ADDR:
2339 MII address of the PHY to check for the Ethernet link state.
2341 - CFG_64BIT_VSPRINTF:
2342 Makes vsprintf (and all *printf functions) support printing
2343 of 64bit values by using the L quantifier
2345 - CFG_64BIT_STRTOUL:
2346 Adds simple_strtoull that returns a 64bit value
2348 Low Level (hardware related) configuration options:
2349 ---------------------------------------------------
2351 - CFG_CACHELINE_SIZE:
2352 Cache Line Size of the CPU.
2355 Default address of the IMMR after system reset.
2357 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2358 and RPXsuper) to be able to adjust the position of
2359 the IMMR register after a reset.
2361 - Floppy Disk Support:
2362 CFG_FDC_DRIVE_NUMBER
2364 the default drive number (default value 0)
2368 defines the spacing between FDC chipset registers
2373 defines the offset of register from address. It
2374 depends on which part of the data bus is connected to
2375 the FDC chipset. (default value 0)
2377 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2378 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2381 if CFG_FDC_HW_INIT is defined, then the function
2382 fdc_hw_init() is called at the beginning of the FDC
2383 setup. fdc_hw_init() must be provided by the board
2384 source code. It is used to make hardware dependant
2387 - CFG_IMMR: Physical address of the Internal Memory.
2388 DO NOT CHANGE unless you know exactly what you're
2389 doing! (11-4) [MPC8xx/82xx systems only]
2391 - CFG_INIT_RAM_ADDR:
2393 Start address of memory area that can be used for
2394 initial data and stack; please note that this must be
2395 writable memory that is working WITHOUT special
2396 initialization, i. e. you CANNOT use normal RAM which
2397 will become available only after programming the
2398 memory controller and running certain initialization
2401 U-Boot uses the following memory types:
2402 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2403 - MPC824X: data cache
2404 - PPC4xx: data cache
2406 - CFG_GBL_DATA_OFFSET:
2408 Offset of the initial data structure in the memory
2409 area defined by CFG_INIT_RAM_ADDR. Usually
2410 CFG_GBL_DATA_OFFSET is chosen such that the initial
2411 data is located at the end of the available space
2412 (sometimes written as (CFG_INIT_RAM_END -
2413 CFG_INIT_DATA_SIZE), and the initial stack is just
2414 below that area (growing from (CFG_INIT_RAM_ADDR +
2415 CFG_GBL_DATA_OFFSET) downward.
2418 On the MPC824X (or other systems that use the data
2419 cache for initial memory) the address chosen for
2420 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2421 point to an otherwise UNUSED address space between
2422 the top of RAM and the start of the PCI space.
2424 - CFG_SIUMCR: SIU Module Configuration (11-6)
2426 - CFG_SYPCR: System Protection Control (11-9)
2428 - CFG_TBSCR: Time Base Status and Control (11-26)
2430 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2432 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2434 - CFG_SCCR: System Clock and reset Control Register (15-27)
2436 - CFG_OR_TIMING_SDRAM:
2440 periodic timer for refresh
2442 - CFG_DER: Debug Event Register (37-47)
2444 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2445 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2446 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2448 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2450 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2451 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2452 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2453 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2455 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2456 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2457 Machine Mode Register and Memory Periodic Timer
2458 Prescaler definitions (SDRAM timing)
2460 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2461 enable I2C microcode relocation patch (MPC8xx);
2462 define relocation offset in DPRAM [DSP2]
2464 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2465 enable SMC microcode relocation patch (MPC8xx);
2466 define relocation offset in DPRAM [SMC1]
2468 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2469 enable SPI microcode relocation patch (MPC8xx);
2470 define relocation offset in DPRAM [SCC4]
2473 Use OSCM clock mode on MBX8xx board. Be careful,
2474 wrong setting might damage your board. Read
2475 doc/README.MBX before setting this variable!
2477 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2478 Offset of the bootmode word in DPRAM used by post
2479 (Power On Self Tests). This definition overrides
2480 #define'd default value in commproc.h resp.
2483 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2484 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2485 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2486 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2487 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2488 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2489 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2490 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2491 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2494 Get DDR timing information from an I2C EEPROM. Common
2495 with pluggable memory modules such as SODIMMs
2498 I2C address of the SPD EEPROM
2501 If SPD EEPROM is on an I2C bus other than the first
2502 one, specify here. Note that the value must resolve
2503 to something your driver can deal with.
2505 - CFG_83XX_DDR_USES_CS0
2506 Only for 83xx systems. If specified, then DDR should
2507 be configured using CS0 and CS1 instead of CS2 and CS3.
2509 - CFG_83XX_DDR_USES_CS0
2510 Only for 83xx systems. If specified, then DDR should
2511 be configured using CS0 and CS1 instead of CS2 and CS3.
2513 - CONFIG_ETHER_ON_FEC[12]
2514 Define to enable FEC[12] on a 8xx series processor.
2516 - CONFIG_FEC[12]_PHY
2517 Define to the hardcoded PHY address which corresponds
2518 to the given FEC; i. e.
2519 #define CONFIG_FEC1_PHY 4
2520 means that the PHY with address 4 is connected to FEC1
2522 When set to -1, means to probe for first available.
2524 - CONFIG_FEC[12]_PHY_NORXERR
2525 The PHY does not have a RXERR line (RMII only).
2526 (so program the FEC to ignore it).
2529 Enable RMII mode for all FECs.
2530 Note that this is a global option, we can't
2531 have one FEC in standard MII mode and another in RMII mode.
2533 - CONFIG_CRC32_VERIFY
2534 Add a verify option to the crc32 command.
2537 => crc32 -v <address> <count> <crc32>
2539 Where address/count indicate a memory area
2540 and crc32 is the correct crc32 which the
2544 Add the "loopw" memory command. This only takes effect if
2545 the memory commands are activated globally (CONFIG_CMD_MEM).
2548 Add the "mdc" and "mwc" memory commands. These are cyclic
2553 This command will print 4 bytes (10,11,12,13) each 500 ms.
2555 => mwc.l 100 12345678 10
2556 This command will write 12345678 to address 100 all 10 ms.
2558 This only takes effect if the memory commands are activated
2559 globally (CONFIG_CMD_MEM).
2561 - CONFIG_SKIP_LOWLEVEL_INIT
2562 - CONFIG_SKIP_RELOCATE_UBOOT
2564 [ARM only] If these variables are defined, then
2565 certain low level initializations (like setting up
2566 the memory controller) are omitted and/or U-Boot does
2567 not relocate itself into RAM.
2568 Normally these variables MUST NOT be defined. The
2569 only exception is when U-Boot is loaded (to RAM) by
2570 some other boot loader or by a debugger which
2571 performs these initializations itself.
2574 Building the Software:
2575 ======================
2577 Building U-Boot has been tested in several native build environments
2578 and in many different cross environments. Of course we cannot support
2579 all possibly existing versions of cross development tools in all
2580 (potentially obsolete) versions. In case of tool chain problems we
2581 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2582 which is extensively used to build and test U-Boot.
2584 If you are not using a native environment, it is assumed that you
2585 have GNU cross compiling tools available in your path. In this case,
2586 you must set the environment variable CROSS_COMPILE in your shell.
2587 Note that no changes to the Makefile or any other source files are
2588 necessary. For example using the ELDK on a 4xx CPU, please enter:
2590 $ CROSS_COMPILE=ppc_4xx-
2591 $ export CROSS_COMPILE
2593 U-Boot is intended to be simple to build. After installing the
2594 sources you must configure U-Boot for one specific board type. This
2599 where "NAME_config" is the name of one of the existing configu-
2600 rations; see the main Makefile for supported names.
2602 Note: for some board special configuration names may exist; check if
2603 additional information is available from the board vendor; for
2604 instance, the TQM823L systems are available without (standard)
2605 or with LCD support. You can select such additional "features"
2606 when choosing the configuration, i. e.
2609 - will configure for a plain TQM823L, i. e. no LCD support
2611 make TQM823L_LCD_config
2612 - will configure for a TQM823L with U-Boot console on LCD
2617 Finally, type "make all", and you should get some working U-Boot
2618 images ready for download to / installation on your system:
2620 - "u-boot.bin" is a raw binary image
2621 - "u-boot" is an image in ELF binary format
2622 - "u-boot.srec" is in Motorola S-Record format
2624 By default the build is performed locally and the objects are saved
2625 in the source directory. One of the two methods can be used to change
2626 this behavior and build U-Boot to some external directory:
2628 1. Add O= to the make command line invocations:
2630 make O=/tmp/build distclean
2631 make O=/tmp/build NAME_config
2632 make O=/tmp/build all
2634 2. Set environment variable BUILD_DIR to point to the desired location:
2636 export BUILD_DIR=/tmp/build
2641 Note that the command line "O=" setting overrides the BUILD_DIR environment
2645 Please be aware that the Makefiles assume you are using GNU make, so
2646 for instance on NetBSD you might need to use "gmake" instead of
2650 If the system board that you have is not listed, then you will need
2651 to port U-Boot to your hardware platform. To do this, follow these
2654 1. Add a new configuration option for your board to the toplevel
2655 "Makefile" and to the "MAKEALL" script, using the existing
2656 entries as examples. Note that here and at many other places
2657 boards and other names are listed in alphabetical sort order. Please
2659 2. Create a new directory to hold your board specific code. Add any
2660 files you need. In your board directory, you will need at least
2661 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2662 3. Create a new configuration file "include/configs/<board>.h" for
2664 3. If you're porting U-Boot to a new CPU, then also create a new
2665 directory to hold your CPU specific code. Add any files you need.
2666 4. Run "make <board>_config" with your new name.
2667 5. Type "make", and you should get a working "u-boot.srec" file
2668 to be installed on your target system.
2669 6. Debug and solve any problems that might arise.
2670 [Of course, this last step is much harder than it sounds.]
2673 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2674 ==============================================================
2676 If you have modified U-Boot sources (for instance added a new board
2677 or support for new devices, a new CPU, etc.) you are expected to
2678 provide feedback to the other developers. The feedback normally takes
2679 the form of a "patch", i. e. a context diff against a certain (latest
2680 official or latest in the git repository) version of U-Boot sources.
2682 But before you submit such a patch, please verify that your modifi-
2683 cation did not break existing code. At least make sure that *ALL* of
2684 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2685 just run the "MAKEALL" script, which will configure and build U-Boot
2686 for ALL supported system. Be warned, this will take a while. You can
2687 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2688 environment variable to the script, i. e. to use the ELDK cross tools
2691 CROSS_COMPILE=ppc_8xx- MAKEALL
2693 or to build on a native PowerPC system you can type
2695 CROSS_COMPILE=' ' MAKEALL
2697 When using the MAKEALL script, the default behaviour is to build
2698 U-Boot in the source directory. This location can be changed by
2699 setting the BUILD_DIR environment variable. Also, for each target
2700 built, the MAKEALL script saves two log files (<target>.ERR and
2701 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2702 location can be changed by setting the MAKEALL_LOGDIR environment
2703 variable. For example:
2705 export BUILD_DIR=/tmp/build
2706 export MAKEALL_LOGDIR=/tmp/log
2707 CROSS_COMPILE=ppc_8xx- MAKEALL
2709 With the above settings build objects are saved in the /tmp/build,
2710 log files are saved in the /tmp/log and the source tree remains clean
2711 during the whole build process.
2714 See also "U-Boot Porting Guide" below.
2717 Monitor Commands - Overview:
2718 ============================
2720 go - start application at address 'addr'
2721 run - run commands in an environment variable
2722 bootm - boot application image from memory
2723 bootp - boot image via network using BootP/TFTP protocol
2724 tftpboot- boot image via network using TFTP protocol
2725 and env variables "ipaddr" and "serverip"
2726 (and eventually "gatewayip")
2727 rarpboot- boot image via network using RARP/TFTP protocol
2728 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2729 loads - load S-Record file over serial line
2730 loadb - load binary file over serial line (kermit mode)
2732 mm - memory modify (auto-incrementing)
2733 nm - memory modify (constant address)
2734 mw - memory write (fill)
2736 cmp - memory compare
2737 crc32 - checksum calculation
2738 imd - i2c memory display
2739 imm - i2c memory modify (auto-incrementing)
2740 inm - i2c memory modify (constant address)
2741 imw - i2c memory write (fill)
2742 icrc32 - i2c checksum calculation
2743 iprobe - probe to discover valid I2C chip addresses
2744 iloop - infinite loop on address range
2745 isdram - print SDRAM configuration information
2746 sspi - SPI utility commands
2747 base - print or set address offset
2748 printenv- print environment variables
2749 setenv - set environment variables
2750 saveenv - save environment variables to persistent storage
2751 protect - enable or disable FLASH write protection
2752 erase - erase FLASH memory
2753 flinfo - print FLASH memory information
2754 bdinfo - print Board Info structure
2755 iminfo - print header information for application image
2756 coninfo - print console devices and informations
2757 ide - IDE sub-system
2758 loop - infinite loop on address range
2759 loopw - infinite write loop on address range
2760 mtest - simple RAM test
2761 icache - enable or disable instruction cache
2762 dcache - enable or disable data cache
2763 reset - Perform RESET of the CPU
2764 echo - echo args to console
2765 version - print monitor version
2766 help - print online help
2767 ? - alias for 'help'
2770 Monitor Commands - Detailed Description:
2771 ========================================
2775 For now: just type "help <command>".
2778 Environment Variables:
2779 ======================
2781 U-Boot supports user configuration using Environment Variables which
2782 can be made persistent by saving to Flash memory.
2784 Environment Variables are set using "setenv", printed using
2785 "printenv", and saved to Flash using "saveenv". Using "setenv"
2786 without a value can be used to delete a variable from the
2787 environment. As long as you don't save the environment you are
2788 working with an in-memory copy. In case the Flash area containing the
2789 environment is erased by accident, a default environment is provided.
2791 Some configuration options can be set using Environment Variables:
2793 baudrate - see CONFIG_BAUDRATE
2795 bootdelay - see CONFIG_BOOTDELAY
2797 bootcmd - see CONFIG_BOOTCOMMAND
2799 bootargs - Boot arguments when booting an RTOS image
2801 bootfile - Name of the image to load with TFTP
2803 bootm_low - Memory range available for image processing in the bootm
2804 command can be restricted. This variable is given as
2805 a hexadecimal number and defines lowest address allowed
2806 for use by the bootm command. See also "bootm_size"
2807 environment variable. Address defined by "bootm_low" is
2808 also the base of the initial memory mapping for the Linux
2809 kernel -- see the description of CFG_BOOTMAPSZ.
2811 bootm_size - Memory range available for image processing in the bootm
2812 command can be restricted. This variable is given as
2813 a hexadecimal number and defines the size of the region
2814 allowed for use by the bootm command. See also "bootm_low"
2815 environment variable.
2817 autoload - if set to "no" (any string beginning with 'n'),
2818 "bootp" will just load perform a lookup of the
2819 configuration from the BOOTP server, but not try to
2820 load any image using TFTP
2822 autoscript - if set to "yes" commands like "loadb", "loady",
2823 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2824 to automatically run script images (by internally
2825 calling "autoscript").
2827 autoscript_uname - if script image is in a format (FIT) this
2828 variable is used to get script subimage unit name.
2830 autostart - if set to "yes", an image loaded using the "bootp",
2831 "rarpboot", "tftpboot" or "diskboot" commands will
2832 be automatically started (by internally calling
2835 If set to "no", a standalone image passed to the
2836 "bootm" command will be copied to the load address
2837 (and eventually uncompressed), but NOT be started.
2838 This can be used to load and uncompress arbitrary
2841 i2cfast - (PPC405GP|PPC405EP only)
2842 if set to 'y' configures Linux I2C driver for fast
2843 mode (400kHZ). This environment variable is used in
2844 initialization code. So, for changes to be effective
2845 it must be saved and board must be reset.
2847 initrd_high - restrict positioning of initrd images:
2848 If this variable is not set, initrd images will be
2849 copied to the highest possible address in RAM; this
2850 is usually what you want since it allows for
2851 maximum initrd size. If for some reason you want to
2852 make sure that the initrd image is loaded below the
2853 CFG_BOOTMAPSZ limit, you can set this environment
2854 variable to a value of "no" or "off" or "0".
2855 Alternatively, you can set it to a maximum upper
2856 address to use (U-Boot will still check that it
2857 does not overwrite the U-Boot stack and data).
2859 For instance, when you have a system with 16 MB
2860 RAM, and want to reserve 4 MB from use by Linux,
2861 you can do this by adding "mem=12M" to the value of
2862 the "bootargs" variable. However, now you must make
2863 sure that the initrd image is placed in the first
2864 12 MB as well - this can be done with
2866 setenv initrd_high 00c00000
2868 If you set initrd_high to 0xFFFFFFFF, this is an
2869 indication to U-Boot that all addresses are legal
2870 for the Linux kernel, including addresses in flash
2871 memory. In this case U-Boot will NOT COPY the
2872 ramdisk at all. This may be useful to reduce the
2873 boot time on your system, but requires that this
2874 feature is supported by your Linux kernel.
2876 ipaddr - IP address; needed for tftpboot command
2878 loadaddr - Default load address for commands like "bootp",
2879 "rarpboot", "tftpboot", "loadb" or "diskboot"
2881 loads_echo - see CONFIG_LOADS_ECHO
2883 serverip - TFTP server IP address; needed for tftpboot command
2885 bootretry - see CONFIG_BOOT_RETRY_TIME
2887 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2889 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2891 ethprime - When CONFIG_NET_MULTI is enabled controls which
2892 interface is used first.
2894 ethact - When CONFIG_NET_MULTI is enabled controls which
2895 interface is currently active. For example you
2896 can do the following
2898 => setenv ethact FEC ETHERNET
2899 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2900 => setenv ethact SCC ETHERNET
2901 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2903 ethrotate - When set to "no" U-Boot does not go through all
2904 available network interfaces.
2905 It just stays at the currently selected interface.
2907 netretry - When set to "no" each network operation will
2908 either succeed or fail without retrying.
2909 When set to "once" the network operation will
2910 fail when all the available network interfaces
2911 are tried once without success.
2912 Useful on scripts which control the retry operation
2915 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2916 if set load address for the NPE microcode
2918 tftpsrcport - If this is set, the value is used for TFTP's
2921 tftpdstport - If this is set, the value is used for TFTP's UDP
2922 destination port instead of the Well Know Port 69.
2924 vlan - When set to a value < 4095 the traffic over
2925 Ethernet is encapsulated/received over 802.1q
2928 The following environment variables may be used and automatically
2929 updated by the network boot commands ("bootp" and "rarpboot"),
2930 depending the information provided by your boot server:
2932 bootfile - see above
2933 dnsip - IP address of your Domain Name Server
2934 dnsip2 - IP address of your secondary Domain Name Server
2935 gatewayip - IP address of the Gateway (Router) to use
2936 hostname - Target hostname
2938 netmask - Subnet Mask
2939 rootpath - Pathname of the root filesystem on the NFS server
2940 serverip - see above
2943 There are two special Environment Variables:
2945 serial# - contains hardware identification information such
2946 as type string and/or serial number
2947 ethaddr - Ethernet address
2949 These variables can be set only once (usually during manufacturing of
2950 the board). U-Boot refuses to delete or overwrite these variables
2951 once they have been set once.
2954 Further special Environment Variables:
2956 ver - Contains the U-Boot version string as printed
2957 with the "version" command. This variable is
2958 readonly (see CONFIG_VERSION_VARIABLE).
2961 Please note that changes to some configuration parameters may take
2962 only effect after the next boot (yes, that's just like Windoze :-).
2965 Command Line Parsing:
2966 =====================
2968 There are two different command line parsers available with U-Boot:
2969 the old "simple" one, and the much more powerful "hush" shell:
2971 Old, simple command line parser:
2972 --------------------------------
2974 - supports environment variables (through setenv / saveenv commands)
2975 - several commands on one line, separated by ';'
2976 - variable substitution using "... ${name} ..." syntax
2977 - special characters ('$', ';') can be escaped by prefixing with '\',
2979 setenv bootcmd bootm \${address}
2980 - You can also escape text by enclosing in single apostrophes, for example:
2981 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2986 - similar to Bourne shell, with control structures like
2987 if...then...else...fi, for...do...done; while...do...done,
2988 until...do...done, ...
2989 - supports environment ("global") variables (through setenv / saveenv
2990 commands) and local shell variables (through standard shell syntax
2991 "name=value"); only environment variables can be used with "run"
2997 (1) If a command line (or an environment variable executed by a "run"
2998 command) contains several commands separated by semicolon, and
2999 one of these commands fails, then the remaining commands will be
3002 (2) If you execute several variables with one call to run (i. e.
3003 calling run with a list of variables as arguments), any failing
3004 command will cause "run" to terminate, i. e. the remaining
3005 variables are not executed.
3007 Note for Redundant Ethernet Interfaces:
3008 =======================================
3010 Some boards come with redundant Ethernet interfaces; U-Boot supports
3011 such configurations and is capable of automatic selection of a
3012 "working" interface when needed. MAC assignment works as follows:
3014 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3015 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3016 "eth1addr" (=>eth1), "eth2addr", ...
3018 If the network interface stores some valid MAC address (for instance
3019 in SROM), this is used as default address if there is NO correspon-
3020 ding setting in the environment; if the corresponding environment
3021 variable is set, this overrides the settings in the card; that means:
3023 o If the SROM has a valid MAC address, and there is no address in the
3024 environment, the SROM's address is used.
3026 o If there is no valid address in the SROM, and a definition in the
3027 environment exists, then the value from the environment variable is
3030 o If both the SROM and the environment contain a MAC address, and
3031 both addresses are the same, this MAC address is used.
3033 o If both the SROM and the environment contain a MAC address, and the
3034 addresses differ, the value from the environment is used and a
3037 o If neither SROM nor the environment contain a MAC address, an error
3044 U-Boot is capable of booting (and performing other auxiliary operations on)
3045 images in two formats:
3047 New uImage format (FIT)
3048 -----------------------
3050 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3051 to Flattened Device Tree). It allows the use of images with multiple
3052 components (several kernels, ramdisks, etc.), with contents protected by
3053 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3059 Old image format is based on binary files which can be basically anything,
3060 preceded by a special header; see the definitions in include/image.h for
3061 details; basically, the header defines the following image properties:
3063 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3064 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3065 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3066 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3068 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3069 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3070 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3071 * Compression Type (uncompressed, gzip, bzip2)
3077 The header is marked by a special Magic Number, and both the header
3078 and the data portions of the image are secured against corruption by
3085 Although U-Boot should support any OS or standalone application
3086 easily, the main focus has always been on Linux during the design of
3089 U-Boot includes many features that so far have been part of some
3090 special "boot loader" code within the Linux kernel. Also, any
3091 "initrd" images to be used are no longer part of one big Linux image;
3092 instead, kernel and "initrd" are separate images. This implementation
3093 serves several purposes:
3095 - the same features can be used for other OS or standalone
3096 applications (for instance: using compressed images to reduce the
3097 Flash memory footprint)
3099 - it becomes much easier to port new Linux kernel versions because
3100 lots of low-level, hardware dependent stuff are done by U-Boot
3102 - the same Linux kernel image can now be used with different "initrd"
3103 images; of course this also means that different kernel images can
3104 be run with the same "initrd". This makes testing easier (you don't
3105 have to build a new "zImage.initrd" Linux image when you just
3106 change a file in your "initrd"). Also, a field-upgrade of the
3107 software is easier now.
3113 Porting Linux to U-Boot based systems:
3114 ---------------------------------------
3116 U-Boot cannot save you from doing all the necessary modifications to
3117 configure the Linux device drivers for use with your target hardware
3118 (no, we don't intend to provide a full virtual machine interface to
3121 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3123 Just make sure your machine specific header file (for instance
3124 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3125 Information structure as we define in include/asm-<arch>/u-boot.h,
3126 and make sure that your definition of IMAP_ADDR uses the same value
3127 as your U-Boot configuration in CFG_IMMR.
3130 Configuring the Linux kernel:
3131 -----------------------------
3133 No specific requirements for U-Boot. Make sure you have some root
3134 device (initial ramdisk, NFS) for your target system.
3137 Building a Linux Image:
3138 -----------------------
3140 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3141 not used. If you use recent kernel source, a new build target
3142 "uImage" will exist which automatically builds an image usable by
3143 U-Boot. Most older kernels also have support for a "pImage" target,
3144 which was introduced for our predecessor project PPCBoot and uses a
3145 100% compatible format.
3154 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3155 encapsulate a compressed Linux kernel image with header information,
3156 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3158 * build a standard "vmlinux" kernel image (in ELF binary format):
3160 * convert the kernel into a raw binary image:
3162 ${CROSS_COMPILE}-objcopy -O binary \
3163 -R .note -R .comment \
3164 -S vmlinux linux.bin
3166 * compress the binary image:
3170 * package compressed binary image for U-Boot:
3172 mkimage -A ppc -O linux -T kernel -C gzip \
3173 -a 0 -e 0 -n "Linux Kernel Image" \
3174 -d linux.bin.gz uImage
3177 The "mkimage" tool can also be used to create ramdisk images for use
3178 with U-Boot, either separated from the Linux kernel image, or
3179 combined into one file. "mkimage" encapsulates the images with a 64
3180 byte header containing information about target architecture,
3181 operating system, image type, compression method, entry points, time
3182 stamp, CRC32 checksums, etc.
3184 "mkimage" can be called in two ways: to verify existing images and
3185 print the header information, or to build new images.
3187 In the first form (with "-l" option) mkimage lists the information
3188 contained in the header of an existing U-Boot image; this includes
3189 checksum verification:
3191 tools/mkimage -l image
3192 -l ==> list image header information
3194 The second form (with "-d" option) is used to build a U-Boot image
3195 from a "data file" which is used as image payload:
3197 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3198 -n name -d data_file image
3199 -A ==> set architecture to 'arch'
3200 -O ==> set operating system to 'os'
3201 -T ==> set image type to 'type'
3202 -C ==> set compression type 'comp'
3203 -a ==> set load address to 'addr' (hex)
3204 -e ==> set entry point to 'ep' (hex)
3205 -n ==> set image name to 'name'
3206 -d ==> use image data from 'datafile'
3208 Right now, all Linux kernels for PowerPC systems use the same load
3209 address (0x00000000), but the entry point address depends on the
3212 - 2.2.x kernels have the entry point at 0x0000000C,
3213 - 2.3.x and later kernels have the entry point at 0x00000000.
3215 So a typical call to build a U-Boot image would read:
3217 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3218 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3219 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3220 > examples/uImage.TQM850L
3221 Image Name: 2.4.4 kernel for TQM850L
3222 Created: Wed Jul 19 02:34:59 2000
3223 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3224 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3225 Load Address: 0x00000000
3226 Entry Point: 0x00000000
3228 To verify the contents of the image (or check for corruption):
3230 -> tools/mkimage -l examples/uImage.TQM850L
3231 Image Name: 2.4.4 kernel for TQM850L
3232 Created: Wed Jul 19 02:34:59 2000
3233 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3234 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3235 Load Address: 0x00000000
3236 Entry Point: 0x00000000
3238 NOTE: for embedded systems where boot time is critical you can trade
3239 speed for memory and install an UNCOMPRESSED image instead: this
3240 needs more space in Flash, but boots much faster since it does not
3241 need to be uncompressed:
3243 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3244 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3245 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3246 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3247 > examples/uImage.TQM850L-uncompressed
3248 Image Name: 2.4.4 kernel for TQM850L
3249 Created: Wed Jul 19 02:34:59 2000
3250 Image Type: PowerPC Linux Kernel Image (uncompressed)
3251 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3252 Load Address: 0x00000000
3253 Entry Point: 0x00000000
3256 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3257 when your kernel is intended to use an initial ramdisk:
3259 -> tools/mkimage -n 'Simple Ramdisk Image' \
3260 > -A ppc -O linux -T ramdisk -C gzip \
3261 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3262 Image Name: Simple Ramdisk Image
3263 Created: Wed Jan 12 14:01:50 2000
3264 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3265 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3266 Load Address: 0x00000000
3267 Entry Point: 0x00000000
3270 Installing a Linux Image:
3271 -------------------------
3273 To downloading a U-Boot image over the serial (console) interface,
3274 you must convert the image to S-Record format:
3276 objcopy -I binary -O srec examples/image examples/image.srec
3278 The 'objcopy' does not understand the information in the U-Boot
3279 image header, so the resulting S-Record file will be relative to
3280 address 0x00000000. To load it to a given address, you need to
3281 specify the target address as 'offset' parameter with the 'loads'
3284 Example: install the image to address 0x40100000 (which on the
3285 TQM8xxL is in the first Flash bank):
3287 => erase 40100000 401FFFFF
3293 ## Ready for S-Record download ...
3294 ~>examples/image.srec
3295 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3297 15989 15990 15991 15992
3298 [file transfer complete]
3300 ## Start Addr = 0x00000000
3303 You can check the success of the download using the 'iminfo' command;
3304 this includes a checksum verification so you can be sure no data
3305 corruption happened:
3309 ## Checking Image at 40100000 ...
3310 Image Name: 2.2.13 for initrd on TQM850L
3311 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3312 Data Size: 335725 Bytes = 327 kB = 0 MB
3313 Load Address: 00000000
3314 Entry Point: 0000000c
3315 Verifying Checksum ... OK
3321 The "bootm" command is used to boot an application that is stored in
3322 memory (RAM or Flash). In case of a Linux kernel image, the contents
3323 of the "bootargs" environment variable is passed to the kernel as
3324 parameters. You can check and modify this variable using the
3325 "printenv" and "setenv" commands:
3328 => printenv bootargs
3329 bootargs=root=/dev/ram
3331 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3333 => printenv bootargs
3334 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3337 ## Booting Linux kernel at 40020000 ...
3338 Image Name: 2.2.13 for NFS on TQM850L
3339 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3340 Data Size: 381681 Bytes = 372 kB = 0 MB
3341 Load Address: 00000000
3342 Entry Point: 0000000c
3343 Verifying Checksum ... OK
3344 Uncompressing Kernel Image ... OK
3345 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
3346 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3347 time_init: decrementer frequency = 187500000/60
3348 Calibrating delay loop... 49.77 BogoMIPS
3349 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3352 If you want to boot a Linux kernel with initial RAM disk, you pass
3353 the memory addresses of both the kernel and the initrd image (PPBCOOT
3354 format!) to the "bootm" command:
3356 => imi 40100000 40200000
3358 ## Checking Image at 40100000 ...
3359 Image Name: 2.2.13 for initrd on TQM850L
3360 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3361 Data Size: 335725 Bytes = 327 kB = 0 MB
3362 Load Address: 00000000
3363 Entry Point: 0000000c
3364 Verifying Checksum ... OK
3366 ## Checking Image at 40200000 ...
3367 Image Name: Simple Ramdisk Image
3368 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3369 Data Size: 566530 Bytes = 553 kB = 0 MB
3370 Load Address: 00000000
3371 Entry Point: 00000000
3372 Verifying Checksum ... OK
3374 => bootm 40100000 40200000
3375 ## Booting Linux kernel at 40100000 ...
3376 Image Name: 2.2.13 for initrd on TQM850L
3377 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3378 Data Size: 335725 Bytes = 327 kB = 0 MB
3379 Load Address: 00000000
3380 Entry Point: 0000000c
3381 Verifying Checksum ... OK
3382 Uncompressing Kernel Image ... OK
3383 ## Loading RAMDisk Image at 40200000 ...
3384 Image Name: Simple Ramdisk Image
3385 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3386 Data Size: 566530 Bytes = 553 kB = 0 MB
3387 Load Address: 00000000
3388 Entry Point: 00000000
3389 Verifying Checksum ... OK
3390 Loading Ramdisk ... OK
3391 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
3392 Boot arguments: root=/dev/ram
3393 time_init: decrementer frequency = 187500000/60
3394 Calibrating delay loop... 49.77 BogoMIPS
3396 RAMDISK: Compressed image found at block 0
3397 VFS: Mounted root (ext2 filesystem).
3401 Boot Linux and pass a flat device tree:
3404 First, U-Boot must be compiled with the appropriate defines. See the section
3405 titled "Linux Kernel Interface" above for a more in depth explanation. The
3406 following is an example of how to start a kernel and pass an updated
3412 oft=oftrees/mpc8540ads.dtb
3413 => tftp $oftaddr $oft
3414 Speed: 1000, full duplex
3416 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3417 Filename 'oftrees/mpc8540ads.dtb'.
3418 Load address: 0x300000
3421 Bytes transferred = 4106 (100a hex)
3422 => tftp $loadaddr $bootfile
3423 Speed: 1000, full duplex
3425 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3427 Load address: 0x200000
3428 Loading:############
3430 Bytes transferred = 1029407 (fb51f hex)
3435 => bootm $loadaddr - $oftaddr
3436 ## Booting image at 00200000 ...
3437 Image Name: Linux-2.6.17-dirty
3438 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3439 Data Size: 1029343 Bytes = 1005.2 kB
3440 Load Address: 00000000
3441 Entry Point: 00000000
3442 Verifying Checksum ... OK
3443 Uncompressing Kernel Image ... OK
3444 Booting using flat device tree at 0x300000
3445 Using MPC85xx ADS machine description
3446 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3450 More About U-Boot Image Types:
3451 ------------------------------
3453 U-Boot supports the following image types:
3455 "Standalone Programs" are directly runnable in the environment
3456 provided by U-Boot; it is expected that (if they behave
3457 well) you can continue to work in U-Boot after return from
3458 the Standalone Program.
3459 "OS Kernel Images" are usually images of some Embedded OS which
3460 will take over control completely. Usually these programs
3461 will install their own set of exception handlers, device
3462 drivers, set up the MMU, etc. - this means, that you cannot
3463 expect to re-enter U-Boot except by resetting the CPU.
3464 "RAMDisk Images" are more or less just data blocks, and their
3465 parameters (address, size) are passed to an OS kernel that is
3467 "Multi-File Images" contain several images, typically an OS
3468 (Linux) kernel image and one or more data images like
3469 RAMDisks. This construct is useful for instance when you want
3470 to boot over the network using BOOTP etc., where the boot
3471 server provides just a single image file, but you want to get
3472 for instance an OS kernel and a RAMDisk image.
3474 "Multi-File Images" start with a list of image sizes, each
3475 image size (in bytes) specified by an "uint32_t" in network
3476 byte order. This list is terminated by an "(uint32_t)0".
3477 Immediately after the terminating 0 follow the images, one by
3478 one, all aligned on "uint32_t" boundaries (size rounded up to
3479 a multiple of 4 bytes).
3481 "Firmware Images" are binary images containing firmware (like
3482 U-Boot or FPGA images) which usually will be programmed to
3485 "Script files" are command sequences that will be executed by
3486 U-Boot's command interpreter; this feature is especially
3487 useful when you configure U-Boot to use a real shell (hush)
3488 as command interpreter.
3494 One of the features of U-Boot is that you can dynamically load and
3495 run "standalone" applications, which can use some resources of
3496 U-Boot like console I/O functions or interrupt services.
3498 Two simple examples are included with the sources:
3503 'examples/hello_world.c' contains a small "Hello World" Demo
3504 application; it is automatically compiled when you build U-Boot.
3505 It's configured to run at address 0x00040004, so you can play with it
3509 ## Ready for S-Record download ...
3510 ~>examples/hello_world.srec
3511 1 2 3 4 5 6 7 8 9 10 11 ...
3512 [file transfer complete]
3514 ## Start Addr = 0x00040004
3516 => go 40004 Hello World! This is a test.
3517 ## Starting application at 0x00040004 ...
3528 Hit any key to exit ...
3530 ## Application terminated, rc = 0x0
3532 Another example, which demonstrates how to register a CPM interrupt
3533 handler with the U-Boot code, can be found in 'examples/timer.c'.
3534 Here, a CPM timer is set up to generate an interrupt every second.
3535 The interrupt service routine is trivial, just printing a '.'
3536 character, but this is just a demo program. The application can be
3537 controlled by the following keys:
3539 ? - print current values og the CPM Timer registers
3540 b - enable interrupts and start timer
3541 e - stop timer and disable interrupts
3542 q - quit application
3545 ## Ready for S-Record download ...
3546 ~>examples/timer.srec
3547 1 2 3 4 5 6 7 8 9 10 11 ...
3548 [file transfer complete]
3550 ## Start Addr = 0x00040004
3553 ## Starting application at 0x00040004 ...
3556 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3559 [q, b, e, ?] Set interval 1000000 us
3562 [q, b, e, ?] ........
3563 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3566 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3569 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3572 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3574 [q, b, e, ?] ...Stopping timer
3576 [q, b, e, ?] ## Application terminated, rc = 0x0
3582 Over time, many people have reported problems when trying to use the
3583 "minicom" terminal emulation program for serial download. I (wd)
3584 consider minicom to be broken, and recommend not to use it. Under
3585 Unix, I recommend to use C-Kermit for general purpose use (and
3586 especially for kermit binary protocol download ("loadb" command), and
3587 use "cu" for S-Record download ("loads" command).
3589 Nevertheless, if you absolutely want to use it try adding this
3590 configuration to your "File transfer protocols" section:
3592 Name Program Name U/D FullScr IO-Red. Multi
3593 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3594 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3600 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3601 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3603 Building requires a cross environment; it is known to work on
3604 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3605 need gmake since the Makefiles are not compatible with BSD make).
3606 Note that the cross-powerpc package does not install include files;
3607 attempting to build U-Boot will fail because <machine/ansi.h> is
3608 missing. This file has to be installed and patched manually:
3610 # cd /usr/pkg/cross/powerpc-netbsd/include
3612 # ln -s powerpc machine
3613 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3614 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3616 Native builds *don't* work due to incompatibilities between native
3617 and U-Boot include files.
3619 Booting assumes that (the first part of) the image booted is a
3620 stage-2 loader which in turn loads and then invokes the kernel
3621 proper. Loader sources will eventually appear in the NetBSD source
3622 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3623 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3626 Implementation Internals:
3627 =========================
3629 The following is not intended to be a complete description of every
3630 implementation detail. However, it should help to understand the
3631 inner workings of U-Boot and make it easier to port it to custom
3635 Initial Stack, Global Data:
3636 ---------------------------
3638 The implementation of U-Boot is complicated by the fact that U-Boot
3639 starts running out of ROM (flash memory), usually without access to
3640 system RAM (because the memory controller is not initialized yet).
3641 This means that we don't have writable Data or BSS segments, and BSS
3642 is not initialized as zero. To be able to get a C environment working
3643 at all, we have to allocate at least a minimal stack. Implementation
3644 options for this are defined and restricted by the CPU used: Some CPU
3645 models provide on-chip memory (like the IMMR area on MPC8xx and
3646 MPC826x processors), on others (parts of) the data cache can be
3647 locked as (mis-) used as memory, etc.
3649 Chris Hallinan posted a good summary of these issues to the
3650 u-boot-users mailing list:
3652 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3653 From: "Chris Hallinan" <clh@net1plus.com>
3654 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3657 Correct me if I'm wrong, folks, but the way I understand it
3658 is this: Using DCACHE as initial RAM for Stack, etc, does not
3659 require any physical RAM backing up the cache. The cleverness
3660 is that the cache is being used as a temporary supply of
3661 necessary storage before the SDRAM controller is setup. It's
3662 beyond the scope of this list to explain the details, but you
3663 can see how this works by studying the cache architecture and
3664 operation in the architecture and processor-specific manuals.
3666 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3667 is another option for the system designer to use as an
3668 initial stack/RAM area prior to SDRAM being available. Either
3669 option should work for you. Using CS 4 should be fine if your
3670 board designers haven't used it for something that would
3671 cause you grief during the initial boot! It is frequently not
3674 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3675 with your processor/board/system design. The default value
3676 you will find in any recent u-boot distribution in
3677 walnut.h should work for you. I'd set it to a value larger
3678 than your SDRAM module. If you have a 64MB SDRAM module, set
3679 it above 400_0000. Just make sure your board has no resources
3680 that are supposed to respond to that address! That code in
3681 start.S has been around a while and should work as is when
3682 you get the config right.
3687 It is essential to remember this, since it has some impact on the C
3688 code for the initialization procedures:
3690 * Initialized global data (data segment) is read-only. Do not attempt
3693 * Do not use any uninitialized global data (or implicitely initialized
3694 as zero data - BSS segment) at all - this is undefined, initiali-
3695 zation is performed later (when relocating to RAM).
3697 * Stack space is very limited. Avoid big data buffers or things like
3700 Having only the stack as writable memory limits means we cannot use
3701 normal global data to share information beween the code. But it
3702 turned out that the implementation of U-Boot can be greatly
3703 simplified by making a global data structure (gd_t) available to all
3704 functions. We could pass a pointer to this data as argument to _all_
3705 functions, but this would bloat the code. Instead we use a feature of
3706 the GCC compiler (Global Register Variables) to share the data: we
3707 place a pointer (gd) to the global data into a register which we
3708 reserve for this purpose.
3710 When choosing a register for such a purpose we are restricted by the
3711 relevant (E)ABI specifications for the current architecture, and by
3712 GCC's implementation.
3714 For PowerPC, the following registers have specific use:
3716 R2: reserved for system use
3717 R3-R4: parameter passing and return values
3718 R5-R10: parameter passing
3719 R13: small data area pointer
3723 (U-Boot also uses R14 as internal GOT pointer.)
3725 ==> U-Boot will use R2 to hold a pointer to the global data
3727 Note: on PPC, we could use a static initializer (since the
3728 address of the global data structure is known at compile time),
3729 but it turned out that reserving a register results in somewhat
3730 smaller code - although the code savings are not that big (on
3731 average for all boards 752 bytes for the whole U-Boot image,
3732 624 text + 127 data).
3734 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3735 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3737 ==> U-Boot will use P5 to hold a pointer to the global data
3739 On ARM, the following registers are used:
3741 R0: function argument word/integer result
3742 R1-R3: function argument word
3744 R10: stack limit (used only if stack checking if enabled)
3745 R11: argument (frame) pointer
3746 R12: temporary workspace
3749 R15: program counter
3751 ==> U-Boot will use R8 to hold a pointer to the global data
3753 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3754 or current versions of GCC may "optimize" the code too much.
3759 U-Boot runs in system state and uses physical addresses, i.e. the
3760 MMU is not used either for address mapping nor for memory protection.
3762 The available memory is mapped to fixed addresses using the memory
3763 controller. In this process, a contiguous block is formed for each
3764 memory type (Flash, SDRAM, SRAM), even when it consists of several
3765 physical memory banks.
3767 U-Boot is installed in the first 128 kB of the first Flash bank (on
3768 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3769 booting and sizing and initializing DRAM, the code relocates itself
3770 to the upper end of DRAM. Immediately below the U-Boot code some
3771 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3772 configuration setting]. Below that, a structure with global Board
3773 Info data is placed, followed by the stack (growing downward).
3775 Additionally, some exception handler code is copied to the low 8 kB
3776 of DRAM (0x00000000 ... 0x00001FFF).
3778 So a typical memory configuration with 16 MB of DRAM could look like
3781 0x0000 0000 Exception Vector code
3784 0x0000 2000 Free for Application Use
3790 0x00FB FF20 Monitor Stack (Growing downward)
3791 0x00FB FFAC Board Info Data and permanent copy of global data
3792 0x00FC 0000 Malloc Arena
3795 0x00FE 0000 RAM Copy of Monitor Code
3796 ... eventually: LCD or video framebuffer
3797 ... eventually: pRAM (Protected RAM - unchanged by reset)
3798 0x00FF FFFF [End of RAM]
3801 System Initialization:
3802 ----------------------
3804 In the reset configuration, U-Boot starts at the reset entry point
3805 (on most PowerPC systems at address 0x00000100). Because of the reset
3806 configuration for CS0# this is a mirror of the onboard Flash memory.
3807 To be able to re-map memory U-Boot then jumps to its link address.
3808 To be able to implement the initialization code in C, a (small!)
3809 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3810 which provide such a feature like MPC8xx or MPC8260), or in a locked
3811 part of the data cache. After that, U-Boot initializes the CPU core,
3812 the caches and the SIU.
3814 Next, all (potentially) available memory banks are mapped using a
3815 preliminary mapping. For example, we put them on 512 MB boundaries
3816 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3817 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3818 programmed for SDRAM access. Using the temporary configuration, a
3819 simple memory test is run that determines the size of the SDRAM
3822 When there is more than one SDRAM bank, and the banks are of
3823 different size, the largest is mapped first. For equal size, the first
3824 bank (CS2#) is mapped first. The first mapping is always for address
3825 0x00000000, with any additional banks following immediately to create
3826 contiguous memory starting from 0.
3828 Then, the monitor installs itself at the upper end of the SDRAM area
3829 and allocates memory for use by malloc() and for the global Board
3830 Info data; also, the exception vector code is copied to the low RAM
3831 pages, and the final stack is set up.
3833 Only after this relocation will you have a "normal" C environment;
3834 until that you are restricted in several ways, mostly because you are
3835 running from ROM, and because the code will have to be relocated to a
3839 U-Boot Porting Guide:
3840 ----------------------
3842 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3846 int main (int argc, char *argv[])
3848 sighandler_t no_more_time;
3850 signal (SIGALRM, no_more_time);
3851 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3853 if (available_money > available_manpower) {
3854 pay consultant to port U-Boot;
3858 Download latest U-Boot source;
3860 Subscribe to u-boot-users mailing list;
3863 email ("Hi, I am new to U-Boot, how do I get started?");
3867 Read the README file in the top level directory;
3868 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3869 Read the source, Luke;
3872 if (available_money > toLocalCurrency ($2500)) {
3875 Add a lot of aggravation and time;
3878 Create your own board support subdirectory;
3880 Create your own board config file;
3884 Add / modify source code;
3888 email ("Hi, I am having problems...");
3890 Send patch file to Wolfgang;
3895 void no_more_time (int sig)
3904 All contributions to U-Boot should conform to the Linux kernel
3905 coding style; see the file "Documentation/CodingStyle" and the script
3906 "scripts/Lindent" in your Linux kernel source directory. In sources
3907 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3908 spaces before parameters to function calls) is actually used.
3910 Source files originating from a different project (for example the
3911 MTD subsystem) are generally exempt from these guidelines and are not
3912 reformated to ease subsequent migration to newer versions of those
3915 Please note that U-Boot is implemented in C (and to some small parts in
3916 Assembler); no C++ is used, so please do not use C++ style comments (//)
3919 Please also stick to the following formatting rules:
3920 - remove any trailing white space
3921 - use TAB characters for indentation, not spaces
3922 - make sure NOT to use DOS '\r\n' line feeds
3923 - do not add more than 2 empty lines to source files
3924 - do not add trailing empty lines to source files
3926 Submissions which do not conform to the standards may be returned
3927 with a request to reformat the changes.
3933 Since the number of patches for U-Boot is growing, we need to
3934 establish some rules. Submissions which do not conform to these rules
3935 may be rejected, even when they contain important and valuable stuff.
3937 Patches shall be sent to the u-boot-users mailing list.
3939 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
3941 When you send a patch, please include the following information with
3944 * For bug fixes: a description of the bug and how your patch fixes
3945 this bug. Please try to include a way of demonstrating that the
3946 patch actually fixes something.
3948 * For new features: a description of the feature and your
3951 * A CHANGELOG entry as plaintext (separate from the patch)
3953 * For major contributions, your entry to the CREDITS file
3955 * When you add support for a new board, don't forget to add this
3956 board to the MAKEALL script, too.
3958 * If your patch adds new configuration options, don't forget to
3959 document these in the README file.
3961 * The patch itself. If you are using git (which is *strongly*
3962 recommended) you can easily generate the patch using the
3963 "git-format-patch". If you then use "git-send-email" to send it to
3964 the U-Boot mailing list, you will avoid most of the common problems
3965 with some other mail clients.
3967 If you cannot use git, use "diff -purN OLD NEW". If your version of
3968 diff does not support these options, then get the latest version of
3971 The current directory when running this command shall be the parent
3972 directory of the U-Boot source tree (i. e. please make sure that
3973 your patch includes sufficient directory information for the
3976 We prefer patches as plain text. MIME attachments are discouraged,
3977 and compressed attachments must not be used.
3979 * If one logical set of modifications affects or creates several
3980 files, all these changes shall be submitted in a SINGLE patch file.
3982 * Changesets that contain different, unrelated modifications shall be
3983 submitted as SEPARATE patches, one patch per changeset.
3988 * Before sending the patch, run the MAKEALL script on your patched
3989 source tree and make sure that no errors or warnings are reported
3990 for any of the boards.
3992 * Keep your modifications to the necessary minimum: A patch
3993 containing several unrelated changes or arbitrary reformats will be
3994 returned with a request to re-formatting / split it.
3996 * If you modify existing code, make sure that your new code does not
3997 add to the memory footprint of the code ;-) Small is beautiful!
3998 When adding new features, these should compile conditionally only
3999 (using #ifdef), and the resulting code with the new feature
4000 disabled must not need more memory than the old code without your
4003 * Remember that there is a size limit of 40 kB per message on the
4004 u-boot-users mailing list. Bigger patches will be moderated. If
4005 they are reasonable and not bigger than 100 kB, they will be
4006 acknowledged. Even bigger patches should be avoided.
projects / kernel / u-boot.git / blob