2 # (C) Copyright 2000 - 2008
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot-users@lists.sourceforge.net>. There is also an archive of
64 previous traffic on the mailing list - please search the archive
65 before asking FAQ's. Please see
66 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Ofifcial releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/UBoot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 - board Board dependent files
142 - common Misc architecture independent functions
143 - cpu CPU specific files
144 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
145 - arm720t Files specific to ARM 720 CPUs
146 - arm920t Files specific to ARM 920 CPUs
147 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148 - imx Files specific to Freescale MC9328 i.MX CPUs
149 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
150 - arm925t Files specific to ARM 925 CPUs
151 - arm926ejs Files specific to ARM 926 CPUs
152 - arm1136 Files specific to ARM 1136 CPUs
153 - at32ap Files specific to Atmel AVR32 AP CPUs
154 - i386 Files specific to i386 CPUs
155 - ixp Files specific to Intel XScale IXP CPUs
156 - 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 transfering 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 addresses
371 CONFIG_OF_BOARD_SETUP
373 Board code has addition modification that it wants to make
374 to the flat device tree before handing it off to the kernel
378 This define fills in the correct boot cpu in the boot
379 param header, the default value is zero if undefined.
384 Define this if you want support for Amba PrimeCell PL010 UARTs.
388 Define this if you want support for Amba PrimeCell PL011 UARTs.
392 If you have Amba PrimeCell PL011 UARTs, set this variable to
393 the clock speed of the UARTs.
397 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
398 define this to a list of base addresses for each (supported)
399 port. See e.g. include/configs/versatile.h
403 Depending on board, define exactly one serial port
404 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
405 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
406 console by defining CONFIG_8xx_CONS_NONE
408 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
409 port routines must be defined elsewhere
410 (i.e. serial_init(), serial_getc(), ...)
413 Enables console device for a color framebuffer. Needs following
414 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
415 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
417 VIDEO_HW_RECTFILL graphic chip supports
420 VIDEO_HW_BITBLT graphic chip supports
421 bit-blit (cf. smiLynxEM)
422 VIDEO_VISIBLE_COLS visible pixel columns
424 VIDEO_VISIBLE_ROWS visible pixel rows
425 VIDEO_PIXEL_SIZE bytes per pixel
426 VIDEO_DATA_FORMAT graphic data format
427 (0-5, cf. cfb_console.c)
428 VIDEO_FB_ADRS framebuffer address
429 VIDEO_KBD_INIT_FCT keyboard int fct
430 (i.e. i8042_kbd_init())
431 VIDEO_TSTC_FCT test char fct
433 VIDEO_GETC_FCT get char fct
435 CONFIG_CONSOLE_CURSOR cursor drawing on/off
436 (requires blink timer
438 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
439 CONFIG_CONSOLE_TIME display time/date info in
441 (requires CONFIG_CMD_DATE)
442 CONFIG_VIDEO_LOGO display Linux logo in
444 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
445 linux_logo.h for logo.
446 Requires CONFIG_VIDEO_LOGO
447 CONFIG_CONSOLE_EXTRA_INFO
448 addional board info beside
451 When CONFIG_CFB_CONSOLE is defined, video console is
452 default i/o. Serial console can be forced with
453 environment 'console=serial'.
455 When CONFIG_SILENT_CONSOLE is defined, all console
456 messages (by U-Boot and Linux!) can be silenced with
457 the "silent" environment variable. See
458 doc/README.silent for more information.
461 CONFIG_BAUDRATE - in bps
462 Select one of the baudrates listed in
463 CFG_BAUDRATE_TABLE, see below.
464 CFG_BRGCLK_PRESCALE, baudrate prescale
466 - Interrupt driven serial port input:
467 CONFIG_SERIAL_SOFTWARE_FIFO
470 Use an interrupt handler for receiving data on the
471 serial port. It also enables using hardware handshake
472 (RTS/CTS) and UART's built-in FIFO. Set the number of
473 bytes the interrupt driven input buffer should have.
475 Leave undefined to disable this feature, including
476 disable the buffer and hardware handshake.
478 - Console UART Number:
482 If defined internal UART1 (and not UART0) is used
483 as default U-Boot console.
485 - Boot Delay: CONFIG_BOOTDELAY - in seconds
486 Delay before automatically booting the default image;
487 set to -1 to disable autoboot.
489 See doc/README.autoboot for these options that
490 work with CONFIG_BOOTDELAY. None are required.
491 CONFIG_BOOT_RETRY_TIME
492 CONFIG_BOOT_RETRY_MIN
493 CONFIG_AUTOBOOT_KEYED
494 CONFIG_AUTOBOOT_PROMPT
495 CONFIG_AUTOBOOT_DELAY_STR
496 CONFIG_AUTOBOOT_STOP_STR
497 CONFIG_AUTOBOOT_DELAY_STR2
498 CONFIG_AUTOBOOT_STOP_STR2
499 CONFIG_ZERO_BOOTDELAY_CHECK
500 CONFIG_RESET_TO_RETRY
504 Only needed when CONFIG_BOOTDELAY is enabled;
505 define a command string that is automatically executed
506 when no character is read on the console interface
507 within "Boot Delay" after reset.
510 This can be used to pass arguments to the bootm
511 command. The value of CONFIG_BOOTARGS goes into the
512 environment value "bootargs".
514 CONFIG_RAMBOOT and CONFIG_NFSBOOT
515 The value of these goes into the environment as
516 "ramboot" and "nfsboot" respectively, and can be used
517 as a convenience, when switching between booting from
523 When this option is #defined, the existence of the
524 environment variable "preboot" will be checked
525 immediately before starting the CONFIG_BOOTDELAY
526 countdown and/or running the auto-boot command resp.
527 entering interactive mode.
529 This feature is especially useful when "preboot" is
530 automatically generated or modified. For an example
531 see the LWMON board specific code: here "preboot" is
532 modified when the user holds down a certain
533 combination of keys on the (special) keyboard when
536 - Serial Download Echo Mode:
538 If defined to 1, all characters received during a
539 serial download (using the "loads" command) are
540 echoed back. This might be needed by some terminal
541 emulations (like "cu"), but may as well just take
542 time on others. This setting #define's the initial
543 value of the "loads_echo" environment variable.
545 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
547 Select one of the baudrates listed in
548 CFG_BAUDRATE_TABLE, see below.
551 Monitor commands can be included or excluded
552 from the build by using the #include files
553 "config_cmd_all.h" and #undef'ing unwanted
554 commands, or using "config_cmd_default.h"
555 and augmenting with additional #define's
558 The default command configuration includes all commands
559 except those marked below with a "*".
561 CONFIG_CMD_ASKENV * ask for env variable
562 CONFIG_CMD_AUTOSCRIPT Autoscript Support
563 CONFIG_CMD_BDI bdinfo
564 CONFIG_CMD_BEDBUG * Include BedBug Debugger
565 CONFIG_CMD_BMP * BMP support
566 CONFIG_CMD_BSP * Board specific commands
567 CONFIG_CMD_BOOTD bootd
568 CONFIG_CMD_CACHE * icache, dcache
569 CONFIG_CMD_CONSOLE coninfo
570 CONFIG_CMD_DATE * support for RTC, date/time...
571 CONFIG_CMD_DHCP * DHCP support
572 CONFIG_CMD_DIAG * Diagnostics
573 CONFIG_CMD_DOC * Disk-On-Chip Support
574 CONFIG_CMD_DTT * Digital Therm and Thermostat
575 CONFIG_CMD_ECHO echo arguments
576 CONFIG_CMD_EEPROM * EEPROM read/write support
577 CONFIG_CMD_ELF * bootelf, bootvx
578 CONFIG_CMD_ENV saveenv
579 CONFIG_CMD_FDC * Floppy Disk Support
580 CONFIG_CMD_FAT * FAT partition support
581 CONFIG_CMD_FDOS * Dos diskette Support
582 CONFIG_CMD_FLASH flinfo, erase, protect
583 CONFIG_CMD_FPGA FPGA device initialization support
584 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
585 CONFIG_CMD_I2C * I2C serial bus support
586 CONFIG_CMD_IDE * IDE harddisk support
587 CONFIG_CMD_IMI iminfo
588 CONFIG_CMD_IMLS List all found images
589 CONFIG_CMD_IMMAP * IMMR dump support
590 CONFIG_CMD_IRQ * irqinfo
591 CONFIG_CMD_ITEST Integer/string test of 2 values
592 CONFIG_CMD_JFFS2 * JFFS2 Support
593 CONFIG_CMD_KGDB * kgdb
594 CONFIG_CMD_LOADB loadb
595 CONFIG_CMD_LOADS loads
596 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
598 CONFIG_CMD_MISC Misc functions like sleep etc
599 CONFIG_CMD_MMC * MMC memory mapped support
600 CONFIG_CMD_MII * MII utility commands
601 CONFIG_CMD_NAND * NAND support
602 CONFIG_CMD_NET bootp, tftpboot, rarpboot
603 CONFIG_CMD_PCI * pciinfo
604 CONFIG_CMD_PCMCIA * PCMCIA support
605 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
607 CONFIG_CMD_PORTIO * Port I/O
608 CONFIG_CMD_REGINFO * Register dump
609 CONFIG_CMD_RUN run command in env variable
610 CONFIG_CMD_SAVES * save S record dump
611 CONFIG_CMD_SCSI * SCSI Support
612 CONFIG_CMD_SDRAM * print SDRAM configuration information
613 (requires CONFIG_CMD_I2C)
614 CONFIG_CMD_SETGETDCR Support for DCR Register access
616 CONFIG_CMD_SPI * SPI serial bus support
617 CONFIG_CMD_USB * USB support
618 CONFIG_CMD_VFD * VFD support (TRAB)
619 CONFIG_CMD_CDP * Cisco Discover Protocol support
620 CONFIG_CMD_FSL * Microblaze FSL support
623 EXAMPLE: If you want all functions except of network
624 support you can write:
626 #include "config_cmd_all.h"
627 #undef CONFIG_CMD_NET
630 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
632 Note: Don't enable the "icache" and "dcache" commands
633 (configuration option CONFIG_CMD_CACHE) unless you know
634 what you (and your U-Boot users) are doing. Data
635 cache cannot be enabled on systems like the 8xx or
636 8260 (where accesses to the IMMR region must be
637 uncached), and it cannot be disabled on all other
638 systems where we (mis-) use the data cache to hold an
639 initial stack and some data.
642 XXX - this list needs to get updated!
646 If this variable is defined, it enables watchdog
647 support. There must be support in the platform specific
648 code for a watchdog. For the 8xx and 8260 CPUs, the
649 SIU Watchdog feature is enabled in the SYPCR
653 CONFIG_VERSION_VARIABLE
654 If this variable is defined, an environment variable
655 named "ver" is created by U-Boot showing the U-Boot
656 version as printed by the "version" command.
657 This variable is readonly.
661 When CONFIG_CMD_DATE is selected, the type of the RTC
662 has to be selected, too. Define exactly one of the
665 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
666 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
667 CONFIG_RTC_MC13783 - use MC13783 RTC
668 CONFIG_RTC_MC146818 - use MC146818 RTC
669 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
670 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
671 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
672 CONFIG_RTC_DS164x - use Dallas DS164x RTC
673 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
674 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
675 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
677 Note that if the RTC uses I2C, then the I2C interface
678 must also be configured. See I2C Support, below.
682 When CONFIG_TIMESTAMP is selected, the timestamp
683 (date and time) of an image is printed by image
684 commands like bootm or iminfo. This option is
685 automatically enabled when you select CONFIG_CMD_DATE .
688 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
689 and/or CONFIG_ISO_PARTITION
691 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
692 CONFIG_CMD_SCSI) you must configure support for at
693 least one partition type as well.
696 CONFIG_IDE_RESET_ROUTINE - this is defined in several
697 board configurations files but used nowhere!
699 CONFIG_IDE_RESET - is this is defined, IDE Reset will
700 be performed by calling the function
701 ide_set_reset(int reset)
702 which has to be defined in a board specific file
707 Set this to enable ATAPI support.
712 Set this to enable support for disks larger than 137GB
713 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
714 Whithout these , LBA48 support uses 32bit variables and will 'only'
715 support disks up to 2.1TB.
718 When enabled, makes the IDE subsystem use 64bit sector addresses.
722 At the moment only there is only support for the
723 SYM53C8XX SCSI controller; define
724 CONFIG_SCSI_SYM53C8XX to enable it.
726 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
727 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
728 CFG_SCSI_MAX_LUN] can be adjusted to define the
729 maximum numbers of LUNs, SCSI ID's and target
731 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
733 - NETWORK Support (PCI):
735 Support for Intel 8254x gigabit chips.
737 CONFIG_E1000_FALLBACK_MAC
738 default MAC for empty eeprom after production.
741 Support for Intel 82557/82559/82559ER chips.
742 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
743 write routine for first time initialisation.
746 Support for Digital 2114x chips.
747 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
748 modem chip initialisation (KS8761/QS6611).
751 Support for National dp83815 chips.
754 Support for National dp8382[01] gigabit chips.
756 - NETWORK Support (other):
758 CONFIG_DRIVER_LAN91C96
759 Support for SMSC's LAN91C96 chips.
762 Define this to hold the physical address
763 of the LAN91C96's I/O space
765 CONFIG_LAN91C96_USE_32_BIT
766 Define this to enable 32 bit addressing
768 CONFIG_DRIVER_SMC91111
769 Support for SMSC's LAN91C111 chip
772 Define this to hold the physical address
773 of the device (I/O space)
775 CONFIG_SMC_USE_32_BIT
776 Define this if data bus is 32 bits
778 CONFIG_SMC_USE_IOFUNCS
779 Define this to use i/o functions instead of macros
780 (some hardware wont work with macros)
782 CONFIG_DRIVER_SMC911X
783 Support for SMSC's LAN911x and LAN921x chips
785 CONFIG_DRIVER_SMC911X_BASE
786 Define this to hold the physical address
787 of the device (I/O space)
789 CONFIG_DRIVER_SMC911X_32_BIT
790 Define this if data bus is 32 bits
792 CONFIG_DRIVER_SMC911X_16_BIT
793 Define this if data bus is 16 bits. If your processor
794 automatically converts one 32 bit word to two 16 bit
795 words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
798 At the moment only the UHCI host controller is
799 supported (PIP405, MIP405, MPC5200); define
800 CONFIG_USB_UHCI to enable it.
801 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
802 and define CONFIG_USB_STORAGE to enable the USB
805 Supported are USB Keyboards and USB Floppy drives
807 MPC5200 USB requires additional defines:
809 for 528 MHz Clock: 0x0001bbbb
811 for differential drivers: 0x00001000
812 for single ended drivers: 0x00005000
814 May be defined to allow interrupt polling
815 instead of using asynchronous interrupts
818 Define the below if you wish to use the USB console.
819 Once firmware is rebuilt from a serial console issue the
820 command "setenv stdin usbtty; setenv stdout usbtty" and
821 attach your usb cable. The Unix command "dmesg" should print
822 it has found a new device. The environment variable usbtty
823 can be set to gserial or cdc_acm to enable your device to
824 appear to a USB host as a Linux gserial device or a
825 Common Device Class Abstract Control Model serial device.
826 If you select usbtty = gserial you should be able to enumerate
828 # modprobe usbserial vendor=0xVendorID product=0xProductID
829 else if using cdc_acm, simply setting the environment
830 variable usbtty to be cdc_acm should suffice. The following
831 might be defined in YourBoardName.h
834 Define this to build a UDC device
837 Define this to have a tty type of device available to
838 talk to the UDC device
840 CFG_CONSOLE_IS_IN_ENV
841 Define this if you want stdin, stdout &/or stderr to
845 CFG_USB_EXTC_CLK 0xBLAH
846 Derive USB clock from external clock "blah"
847 - CFG_USB_EXTC_CLK 0x02
849 CFG_USB_BRG_CLK 0xBLAH
850 Derive USB clock from brgclk
851 - CFG_USB_BRG_CLK 0x04
853 If you have a USB-IF assigned VendorID then you may wish to
854 define your own vendor specific values either in BoardName.h
855 or directly in usbd_vendor_info.h. If you don't define
856 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
857 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
858 should pretend to be a Linux device to it's target host.
860 CONFIG_USBD_MANUFACTURER
861 Define this string as the name of your company for
862 - CONFIG_USBD_MANUFACTURER "my company"
864 CONFIG_USBD_PRODUCT_NAME
865 Define this string as the name of your product
866 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
869 Define this as your assigned Vendor ID from the USB
870 Implementors Forum. This *must* be a genuine Vendor ID
871 to avoid polluting the USB namespace.
872 - CONFIG_USBD_VENDORID 0xFFFF
874 CONFIG_USBD_PRODUCTID
875 Define this as the unique Product ID
877 - CONFIG_USBD_PRODUCTID 0xFFFF
881 The MMC controller on the Intel PXA is supported. To
882 enable this define CONFIG_MMC. The MMC can be
883 accessed from the boot prompt by mapping the device
884 to physical memory similar to flash. Command line is
885 enabled with CONFIG_CMD_MMC. The MMC driver also works with
886 the FAT fs. This is enabled with CONFIG_CMD_FAT.
888 - Journaling Flash filesystem support:
889 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
890 CONFIG_JFFS2_NAND_DEV
891 Define these for a default partition on a NAND device
893 CFG_JFFS2_FIRST_SECTOR,
894 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
895 Define these for a default partition on a NOR device
898 Define this to create an own partition. You have to provide a
899 function struct part_info* jffs2_part_info(int part_num)
901 If you define only one JFFS2 partition you may also want to
902 #define CFG_JFFS_SINGLE_PART 1
903 to disable the command chpart. This is the default when you
904 have not defined a custom partition
909 Define this to enable standard (PC-Style) keyboard
913 Standard PC keyboard driver with US (is default) and
914 GERMAN key layout (switch via environment 'keymap=de') support.
915 Export function i8042_kbd_init, i8042_tstc and i8042_getc
916 for cfb_console. Supports cursor blinking.
921 Define this to enable video support (for output to
926 Enable Chips & Technologies 69000 Video chip
928 CONFIG_VIDEO_SMI_LYNXEM
929 Enable Silicon Motion SMI 712/710/810 Video chip. The
930 video output is selected via environment 'videoout'
931 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
934 For the CT69000 and SMI_LYNXEM drivers, videomode is
935 selected via environment 'videomode'. Two diferent ways
937 - "videomode=num" 'num' is a standard LiLo mode numbers.
938 Following standard modes are supported (* is default):
940 Colors 640x480 800x600 1024x768 1152x864 1280x1024
941 -------------+---------------------------------------------
942 8 bits | 0x301* 0x303 0x305 0x161 0x307
943 15 bits | 0x310 0x313 0x316 0x162 0x319
944 16 bits | 0x311 0x314 0x317 0x163 0x31A
945 24 bits | 0x312 0x315 0x318 ? 0x31B
946 -------------+---------------------------------------------
947 (i.e. setenv videomode 317; saveenv; reset;)
949 - "videomode=bootargs" all the video parameters are parsed
950 from the bootargs. (See drivers/video/videomodes.c)
953 CONFIG_VIDEO_SED13806
954 Enable Epson SED13806 driver. This driver supports 8bpp
955 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
956 or CONFIG_VIDEO_SED13806_16BPP
961 Define this to enable a custom keyboard support.
962 This simply calls drv_keyboard_init() which must be
963 defined in your board-specific files.
964 The only board using this so far is RBC823.
966 - LCD Support: CONFIG_LCD
968 Define this to enable LCD support (for output to LCD
969 display); also select one of the supported displays
970 by defining one of these:
974 HITACHI TX09D70VM1CCA, 3.5", 240x320.
976 CONFIG_NEC_NL6448AC33:
978 NEC NL6448AC33-18. Active, color, single scan.
980 CONFIG_NEC_NL6448BC20
982 NEC NL6448BC20-08. 6.5", 640x480.
983 Active, color, single scan.
985 CONFIG_NEC_NL6448BC33_54
987 NEC NL6448BC33-54. 10.4", 640x480.
988 Active, color, single scan.
992 Sharp 320x240. Active, color, single scan.
993 It isn't 16x9, and I am not sure what it is.
995 CONFIG_SHARP_LQ64D341
997 Sharp LQ64D341 display, 640x480.
998 Active, color, single scan.
1002 HLD1045 display, 640x480.
1003 Active, color, single scan.
1007 Optrex CBL50840-2 NF-FW 99 22 M5
1009 Hitachi LMG6912RPFC-00T
1013 320x240. Black & white.
1015 Normally display is black on white background; define
1016 CFG_WHITE_ON_BLACK to get it inverted.
1018 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1020 If this option is set, the environment is checked for
1021 a variable "splashimage". If found, the usual display
1022 of logo, copyright and system information on the LCD
1023 is suppressed and the BMP image at the address
1024 specified in "splashimage" is loaded instead. The
1025 console is redirected to the "nulldev", too. This
1026 allows for a "silent" boot where a splash screen is
1027 loaded very quickly after power-on.
1029 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1031 If this option is set, additionally to standard BMP
1032 images, gzipped BMP images can be displayed via the
1033 splashscreen support or the bmp command.
1035 - Compression support:
1038 If this option is set, support for bzip2 compressed
1039 images is included. If not, only uncompressed and gzip
1040 compressed images are supported.
1042 NOTE: the bzip2 algorithm requires a lot of RAM, so
1043 the malloc area (as defined by CFG_MALLOC_LEN) should
1049 The address of PHY on MII bus.
1051 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1053 The clock frequency of the MII bus
1057 If this option is set, support for speed/duplex
1058 detection of Gigabit PHY is included.
1060 CONFIG_PHY_RESET_DELAY
1062 Some PHY like Intel LXT971A need extra delay after
1063 reset before any MII register access is possible.
1064 For such PHY, set this option to the usec delay
1065 required. (minimum 300usec for LXT971A)
1067 CONFIG_PHY_CMD_DELAY (ppc4xx)
1069 Some PHY like Intel LXT971A need extra delay after
1070 command issued before MII status register can be read
1077 Define a default value for ethernet address to use
1078 for the respective ethernet interface, in case this
1079 is not determined automatically.
1084 Define a default value for the IP address to use for
1085 the default ethernet interface, in case this is not
1086 determined through e.g. bootp.
1088 - Server IP address:
1091 Defines a default value for theIP address of a TFTP
1092 server to contact when using the "tftboot" command.
1094 - Multicast TFTP Mode:
1097 Defines whether you want to support multicast TFTP as per
1098 rfc-2090; for example to work with atftp. Lets lots of targets
1099 tftp down the same boot image concurrently. Note: the ethernet
1100 driver in use must provide a function: mcast() to join/leave a
1103 CONFIG_BOOTP_RANDOM_DELAY
1104 - BOOTP Recovery Mode:
1105 CONFIG_BOOTP_RANDOM_DELAY
1107 If you have many targets in a network that try to
1108 boot using BOOTP, you may want to avoid that all
1109 systems send out BOOTP requests at precisely the same
1110 moment (which would happen for instance at recovery
1111 from a power failure, when all systems will try to
1112 boot, thus flooding the BOOTP server. Defining
1113 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1114 inserted before sending out BOOTP requests. The
1115 following delays are inserted then:
1117 1st BOOTP request: delay 0 ... 1 sec
1118 2nd BOOTP request: delay 0 ... 2 sec
1119 3rd BOOTP request: delay 0 ... 4 sec
1121 BOOTP requests: delay 0 ... 8 sec
1123 - DHCP Advanced Options:
1124 You can fine tune the DHCP functionality by defining
1125 CONFIG_BOOTP_* symbols:
1127 CONFIG_BOOTP_SUBNETMASK
1128 CONFIG_BOOTP_GATEWAY
1129 CONFIG_BOOTP_HOSTNAME
1130 CONFIG_BOOTP_NISDOMAIN
1131 CONFIG_BOOTP_BOOTPATH
1132 CONFIG_BOOTP_BOOTFILESIZE
1135 CONFIG_BOOTP_SEND_HOSTNAME
1136 CONFIG_BOOTP_NTPSERVER
1137 CONFIG_BOOTP_TIMEOFFSET
1138 CONFIG_BOOTP_VENDOREX
1140 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1141 environment variable, not the BOOTP server.
1143 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1144 serverip from a DHCP server, it is possible that more
1145 than one DNS serverip is offered to the client.
1146 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1147 serverip will be stored in the additional environment
1148 variable "dnsip2". The first DNS serverip is always
1149 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1152 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1153 to do a dynamic update of a DNS server. To do this, they
1154 need the hostname of the DHCP requester.
1155 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1156 of the "hostname" environment variable is passed as
1157 option 12 to the DHCP server.
1159 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1161 A 32bit value in microseconds for a delay between
1162 receiving a "DHCP Offer" and sending the "DHCP Request".
1163 This fixes a problem with certain DHCP servers that don't
1164 respond 100% of the time to a "DHCP request". E.g. On an
1165 AT91RM9200 processor running at 180MHz, this delay needed
1166 to be *at least* 15,000 usec before a Windows Server 2003
1167 DHCP server would reply 100% of the time. I recommend at
1168 least 50,000 usec to be safe. The alternative is to hope
1169 that one of the retries will be successful but note that
1170 the DHCP timeout and retry process takes a longer than
1174 CONFIG_CDP_DEVICE_ID
1176 The device id used in CDP trigger frames.
1178 CONFIG_CDP_DEVICE_ID_PREFIX
1180 A two character string which is prefixed to the MAC address
1185 A printf format string which contains the ascii name of
1186 the port. Normally is set to "eth%d" which sets
1187 eth0 for the first ethernet, eth1 for the second etc.
1189 CONFIG_CDP_CAPABILITIES
1191 A 32bit integer which indicates the device capabilities;
1192 0x00000010 for a normal host which does not forwards.
1196 An ascii string containing the version of the software.
1200 An ascii string containing the name of the platform.
1204 A 32bit integer sent on the trigger.
1206 CONFIG_CDP_POWER_CONSUMPTION
1208 A 16bit integer containing the power consumption of the
1209 device in .1 of milliwatts.
1211 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1213 A byte containing the id of the VLAN.
1215 - Status LED: CONFIG_STATUS_LED
1217 Several configurations allow to display the current
1218 status using a LED. For instance, the LED will blink
1219 fast while running U-Boot code, stop blinking as
1220 soon as a reply to a BOOTP request was received, and
1221 start blinking slow once the Linux kernel is running
1222 (supported by a status LED driver in the Linux
1223 kernel). Defining CONFIG_STATUS_LED enables this
1226 - CAN Support: CONFIG_CAN_DRIVER
1228 Defining CONFIG_CAN_DRIVER enables CAN driver support
1229 on those systems that support this (optional)
1230 feature, like the TQM8xxL modules.
1232 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1234 These enable I2C serial bus commands. Defining either of
1235 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1236 include the appropriate I2C driver for the selected cpu.
1238 This will allow you to use i2c commands at the u-boot
1239 command line (as long as you set CONFIG_CMD_I2C in
1240 CONFIG_COMMANDS) and communicate with i2c based realtime
1241 clock chips. See common/cmd_i2c.c for a description of the
1242 command line interface.
1244 CONFIG_I2C_CMD_TREE is a recommended option that places
1245 all I2C commands under a single 'i2c' root command. The
1246 older 'imm', 'imd', 'iprobe' etc. commands are considered
1247 deprecated and may disappear in the future.
1249 CONFIG_HARD_I2C selects a hardware I2C controller.
1251 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1252 bit-banging) driver instead of CPM or similar hardware
1255 There are several other quantities that must also be
1256 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1258 In both cases you will need to define CFG_I2C_SPEED
1259 to be the frequency (in Hz) at which you wish your i2c bus
1260 to run and CFG_I2C_SLAVE to be the address of this node (ie
1261 the cpu's i2c node address).
1263 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1264 sets the cpu up as a master node and so its address should
1265 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1266 p.16-473). So, set CFG_I2C_SLAVE to 0.
1268 That's all that's required for CONFIG_HARD_I2C.
1270 If you use the software i2c interface (CONFIG_SOFT_I2C)
1271 then the following macros need to be defined (examples are
1272 from include/configs/lwmon.h):
1276 (Optional). Any commands necessary to enable the I2C
1277 controller or configure ports.
1279 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1283 (Only for MPC8260 CPU). The I/O port to use (the code
1284 assumes both bits are on the same port). Valid values
1285 are 0..3 for ports A..D.
1289 The code necessary to make the I2C data line active
1290 (driven). If the data line is open collector, this
1293 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1297 The code necessary to make the I2C data line tri-stated
1298 (inactive). If the data line is open collector, this
1301 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1305 Code that returns TRUE if the I2C data line is high,
1308 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1312 If <bit> is TRUE, sets the I2C data line high. If it
1313 is FALSE, it clears it (low).
1315 eg: #define I2C_SDA(bit) \
1316 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1317 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1321 If <bit> is TRUE, sets the I2C clock line high. If it
1322 is FALSE, it clears it (low).
1324 eg: #define I2C_SCL(bit) \
1325 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1326 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1330 This delay is invoked four times per clock cycle so this
1331 controls the rate of data transfer. The data rate thus
1332 is 1 / (I2C_DELAY * 4). Often defined to be something
1335 #define I2C_DELAY udelay(2)
1339 When a board is reset during an i2c bus transfer
1340 chips might think that the current transfer is still
1341 in progress. On some boards it is possible to access
1342 the i2c SCLK line directly, either by using the
1343 processor pin as a GPIO or by having a second pin
1344 connected to the bus. If this option is defined a
1345 custom i2c_init_board() routine in boards/xxx/board.c
1346 is run early in the boot sequence.
1348 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1350 This option enables configuration of bi_iic_fast[] flags
1351 in u-boot bd_info structure based on u-boot environment
1352 variable "i2cfast". (see also i2cfast)
1354 CONFIG_I2C_MULTI_BUS
1356 This option allows the use of multiple I2C buses, each of which
1357 must have a controller. At any point in time, only one bus is
1358 active. To switch to a different bus, use the 'i2c dev' command.
1359 Note that bus numbering is zero-based.
1363 This option specifies a list of I2C devices that will be skipped
1364 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1365 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1366 pairs. Otherwise, specify a 1D array of device addresses
1369 #undef CONFIG_I2C_MULTI_BUS
1370 #define CFG_I2C_NOPROBES {0x50,0x68}
1372 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1374 #define CONFIG_I2C_MULTI_BUS
1375 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1377 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1381 If defined, then this indicates the I2C bus number for DDR SPD.
1382 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1386 If defined, then this indicates the I2C bus number for the RTC.
1387 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1391 If defined, then this indicates the I2C bus number for the DTT.
1392 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1396 Define this option if you want to use Freescale's I2C driver in
1397 drivers/i2c/fsl_i2c.c.
1400 - SPI Support: CONFIG_SPI
1402 Enables SPI driver (so far only tested with
1403 SPI EEPROM, also an instance works with Crystal A/D and
1404 D/As on the SACSng board)
1408 Enables extended (16-bit) SPI EEPROM addressing.
1409 (symmetrical to CONFIG_I2C_X)
1413 Enables a software (bit-bang) SPI driver rather than
1414 using hardware support. This is a general purpose
1415 driver that only requires three general I/O port pins
1416 (two outputs, one input) to function. If this is
1417 defined, the board configuration must define several
1418 SPI configuration items (port pins to use, etc). For
1419 an example, see include/configs/sacsng.h.
1423 Enables a hardware SPI driver for general-purpose reads
1424 and writes. As with CONFIG_SOFT_SPI, the board configuration
1425 must define a list of chip-select function pointers.
1426 Currently supported on some MPC8xxx processors. For an
1427 example, see include/configs/mpc8349emds.h.
1431 Enables the driver for the SPI controllers on i.MX and MXC
1432 SoCs. Currently only i.MX31 is supported.
1434 - FPGA Support: CONFIG_FPGA
1436 Enables FPGA subsystem.
1438 CONFIG_FPGA_<vendor>
1440 Enables support for specific chip vendors.
1443 CONFIG_FPGA_<family>
1445 Enables support for FPGA family.
1446 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1450 Specify the number of FPGA devices to support.
1452 CFG_FPGA_PROG_FEEDBACK
1454 Enable printing of hash marks during FPGA configuration.
1458 Enable checks on FPGA configuration interface busy
1459 status by the configuration function. This option
1460 will require a board or device specific function to
1465 If defined, a function that provides delays in the FPGA
1466 configuration driver.
1468 CFG_FPGA_CHECK_CTRLC
1469 Allow Control-C to interrupt FPGA configuration
1471 CFG_FPGA_CHECK_ERROR
1473 Check for configuration errors during FPGA bitfile
1474 loading. For example, abort during Virtex II
1475 configuration if the INIT_B line goes low (which
1476 indicated a CRC error).
1480 Maximum time to wait for the INIT_B line to deassert
1481 after PROB_B has been deasserted during a Virtex II
1482 FPGA configuration sequence. The default time is 500
1487 Maximum time to wait for BUSY to deassert during
1488 Virtex II FPGA configuration. The default is 5 mS.
1490 CFG_FPGA_WAIT_CONFIG
1492 Time to wait after FPGA configuration. The default is
1495 - Configuration Management:
1498 If defined, this string will be added to the U-Boot
1499 version information (U_BOOT_VERSION)
1501 - Vendor Parameter Protection:
1503 U-Boot considers the values of the environment
1504 variables "serial#" (Board Serial Number) and
1505 "ethaddr" (Ethernet Address) to be parameters that
1506 are set once by the board vendor / manufacturer, and
1507 protects these variables from casual modification by
1508 the user. Once set, these variables are read-only,
1509 and write or delete attempts are rejected. You can
1510 change this behviour:
1512 If CONFIG_ENV_OVERWRITE is #defined in your config
1513 file, the write protection for vendor parameters is
1514 completely disabled. Anybody can change or delete
1517 Alternatively, if you #define _both_ CONFIG_ETHADDR
1518 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1519 ethernet address is installed in the environment,
1520 which can be changed exactly ONCE by the user. [The
1521 serial# is unaffected by this, i. e. it remains
1527 Define this variable to enable the reservation of
1528 "protected RAM", i. e. RAM which is not overwritten
1529 by U-Boot. Define CONFIG_PRAM to hold the number of
1530 kB you want to reserve for pRAM. You can overwrite
1531 this default value by defining an environment
1532 variable "pram" to the number of kB you want to
1533 reserve. Note that the board info structure will
1534 still show the full amount of RAM. If pRAM is
1535 reserved, a new environment variable "mem" will
1536 automatically be defined to hold the amount of
1537 remaining RAM in a form that can be passed as boot
1538 argument to Linux, for instance like that:
1540 setenv bootargs ... mem=\${mem}
1543 This way you can tell Linux not to use this memory,
1544 either, which results in a memory region that will
1545 not be affected by reboots.
1547 *WARNING* If your board configuration uses automatic
1548 detection of the RAM size, you must make sure that
1549 this memory test is non-destructive. So far, the
1550 following board configurations are known to be
1553 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1554 HERMES, IP860, RPXlite, LWMON, LANTEC,
1555 PCU_E, FLAGADM, TQM8260
1560 Define this variable to stop the system in case of a
1561 fatal error, so that you have to reset it manually.
1562 This is probably NOT a good idea for an embedded
1563 system where you want to system to reboot
1564 automatically as fast as possible, but it may be
1565 useful during development since you can try to debug
1566 the conditions that lead to the situation.
1568 CONFIG_NET_RETRY_COUNT
1570 This variable defines the number of retries for
1571 network operations like ARP, RARP, TFTP, or BOOTP
1572 before giving up the operation. If not defined, a
1573 default value of 5 is used.
1577 Timeout waiting for an ARP reply in milliseconds.
1579 - Command Interpreter:
1580 CONFIG_AUTO_COMPLETE
1582 Enable auto completion of commands using TAB.
1584 Note that this feature has NOT been implemented yet
1585 for the "hush" shell.
1590 Define this variable to enable the "hush" shell (from
1591 Busybox) as command line interpreter, thus enabling
1592 powerful command line syntax like
1593 if...then...else...fi conditionals or `&&' and '||'
1594 constructs ("shell scripts").
1596 If undefined, you get the old, much simpler behaviour
1597 with a somewhat smaller memory footprint.
1602 This defines the secondary prompt string, which is
1603 printed when the command interpreter needs more input
1604 to complete a command. Usually "> ".
1608 In the current implementation, the local variables
1609 space and global environment variables space are
1610 separated. Local variables are those you define by
1611 simply typing `name=value'. To access a local
1612 variable later on, you have write `$name' or
1613 `${name}'; to execute the contents of a variable
1614 directly type `$name' at the command prompt.
1616 Global environment variables are those you use
1617 setenv/printenv to work with. To run a command stored
1618 in such a variable, you need to use the run command,
1619 and you must not use the '$' sign to access them.
1621 To store commands and special characters in a
1622 variable, please use double quotation marks
1623 surrounding the whole text of the variable, instead
1624 of the backslashes before semicolons and special
1627 - Commandline Editing and History:
1628 CONFIG_CMDLINE_EDITING
1630 Enable editiong and History functions for interactive
1631 commandline input operations
1633 - Default Environment:
1634 CONFIG_EXTRA_ENV_SETTINGS
1636 Define this to contain any number of null terminated
1637 strings (variable = value pairs) that will be part of
1638 the default environment compiled into the boot image.
1640 For example, place something like this in your
1641 board's config file:
1643 #define CONFIG_EXTRA_ENV_SETTINGS \
1647 Warning: This method is based on knowledge about the
1648 internal format how the environment is stored by the
1649 U-Boot code. This is NOT an official, exported
1650 interface! Although it is unlikely that this format
1651 will change soon, there is no guarantee either.
1652 You better know what you are doing here.
1654 Note: overly (ab)use of the default environment is
1655 discouraged. Make sure to check other ways to preset
1656 the environment like the autoscript function or the
1659 - DataFlash Support:
1660 CONFIG_HAS_DATAFLASH
1662 Defining this option enables DataFlash features and
1663 allows to read/write in Dataflash via the standard
1666 - SystemACE Support:
1669 Adding this option adds support for Xilinx SystemACE
1670 chips attached via some sort of local bus. The address
1671 of the chip must alsh be defined in the
1672 CFG_SYSTEMACE_BASE macro. For example:
1674 #define CONFIG_SYSTEMACE
1675 #define CFG_SYSTEMACE_BASE 0xf0000000
1677 When SystemACE support is added, the "ace" device type
1678 becomes available to the fat commands, i.e. fatls.
1680 - TFTP Fixed UDP Port:
1683 If this is defined, the environment variable tftpsrcp
1684 is used to supply the TFTP UDP source port value.
1685 If tftpsrcp isn't defined, the normal pseudo-random port
1686 number generator is used.
1688 Also, the environment variable tftpdstp is used to supply
1689 the TFTP UDP destination port value. If tftpdstp isn't
1690 defined, the normal port 69 is used.
1692 The purpose for tftpsrcp is to allow a TFTP server to
1693 blindly start the TFTP transfer using the pre-configured
1694 target IP address and UDP port. This has the effect of
1695 "punching through" the (Windows XP) firewall, allowing
1696 the remainder of the TFTP transfer to proceed normally.
1697 A better solution is to properly configure the firewall,
1698 but sometimes that is not allowed.
1700 - Show boot progress:
1701 CONFIG_SHOW_BOOT_PROGRESS
1703 Defining this option allows to add some board-
1704 specific code (calling a user-provided function
1705 "show_boot_progress(int)") that enables you to show
1706 the system's boot progress on some display (for
1707 example, some LED's) on your board. At the moment,
1708 the following checkpoints are implemented:
1710 Legacy uImage format:
1713 1 common/cmd_bootm.c before attempting to boot an image
1714 -1 common/cmd_bootm.c Image header has bad magic number
1715 2 common/cmd_bootm.c Image header has correct magic number
1716 -2 common/cmd_bootm.c Image header has bad checksum
1717 3 common/cmd_bootm.c Image header has correct checksum
1718 -3 common/cmd_bootm.c Image data has bad checksum
1719 4 common/cmd_bootm.c Image data has correct checksum
1720 -4 common/cmd_bootm.c Image is for unsupported architecture
1721 5 common/cmd_bootm.c Architecture check OK
1722 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1723 6 common/cmd_bootm.c Image Type check OK
1724 -6 common/cmd_bootm.c gunzip uncompression error
1725 -7 common/cmd_bootm.c Unimplemented compression type
1726 7 common/cmd_bootm.c Uncompression OK
1727 8 common/cmd_bootm.c No uncompress/copy overwrite error
1728 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1730 9 common/image.c Start initial ramdisk verification
1731 -10 common/image.c Ramdisk header has bad magic number
1732 -11 common/image.c Ramdisk header has bad checksum
1733 10 common/image.c Ramdisk header is OK
1734 -12 common/image.c Ramdisk data has bad checksum
1735 11 common/image.c Ramdisk data has correct checksum
1736 12 common/image.c Ramdisk verification complete, start loading
1737 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1738 13 common/image.c Start multifile image verification
1739 14 common/image.c No initial ramdisk, no multifile, continue.
1741 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1743 -30 lib_ppc/board.c Fatal error, hang the system
1744 -31 post/post.c POST test failed, detected by post_output_backlog()
1745 -32 post/post.c POST test failed, detected by post_run_single()
1747 34 common/cmd_doc.c before loading a Image from a DOC device
1748 -35 common/cmd_doc.c Bad usage of "doc" command
1749 35 common/cmd_doc.c correct usage of "doc" command
1750 -36 common/cmd_doc.c No boot device
1751 36 common/cmd_doc.c correct boot device
1752 -37 common/cmd_doc.c Unknown Chip ID on boot device
1753 37 common/cmd_doc.c correct chip ID found, device available
1754 -38 common/cmd_doc.c Read Error on boot device
1755 38 common/cmd_doc.c reading Image header from DOC device OK
1756 -39 common/cmd_doc.c Image header has bad magic number
1757 39 common/cmd_doc.c Image header has correct magic number
1758 -40 common/cmd_doc.c Error reading Image from DOC device
1759 40 common/cmd_doc.c Image header has correct magic number
1760 41 common/cmd_ide.c before loading a Image from a IDE device
1761 -42 common/cmd_ide.c Bad usage of "ide" command
1762 42 common/cmd_ide.c correct usage of "ide" command
1763 -43 common/cmd_ide.c No boot device
1764 43 common/cmd_ide.c boot device found
1765 -44 common/cmd_ide.c Device not available
1766 44 common/cmd_ide.c Device available
1767 -45 common/cmd_ide.c wrong partition selected
1768 45 common/cmd_ide.c partition selected
1769 -46 common/cmd_ide.c Unknown partition table
1770 46 common/cmd_ide.c valid partition table found
1771 -47 common/cmd_ide.c Invalid partition type
1772 47 common/cmd_ide.c correct partition type
1773 -48 common/cmd_ide.c Error reading Image Header on boot device
1774 48 common/cmd_ide.c reading Image Header from IDE device OK
1775 -49 common/cmd_ide.c Image header has bad magic number
1776 49 common/cmd_ide.c Image header has correct magic number
1777 -50 common/cmd_ide.c Image header has bad checksum
1778 50 common/cmd_ide.c Image header has correct checksum
1779 -51 common/cmd_ide.c Error reading Image from IDE device
1780 51 common/cmd_ide.c reading Image from IDE device OK
1781 52 common/cmd_nand.c before loading a Image from a NAND device
1782 -53 common/cmd_nand.c Bad usage of "nand" command
1783 53 common/cmd_nand.c correct usage of "nand" command
1784 -54 common/cmd_nand.c No boot device
1785 54 common/cmd_nand.c boot device found
1786 -55 common/cmd_nand.c Unknown Chip ID on boot device
1787 55 common/cmd_nand.c correct chip ID found, device available
1788 -56 common/cmd_nand.c Error reading Image Header on boot device
1789 56 common/cmd_nand.c reading Image Header from NAND device OK
1790 -57 common/cmd_nand.c Image header has bad magic number
1791 57 common/cmd_nand.c Image header has correct magic number
1792 -58 common/cmd_nand.c Error reading Image from NAND device
1793 58 common/cmd_nand.c reading Image from NAND device OK
1795 -60 common/env_common.c Environment has a bad CRC, using default
1797 64 net/eth.c starting with Ethernetconfiguration.
1798 -64 net/eth.c no Ethernet found.
1799 65 net/eth.c Ethernet found.
1801 -80 common/cmd_net.c usage wrong
1802 80 common/cmd_net.c before calling NetLoop()
1803 -81 common/cmd_net.c some error in NetLoop() occured
1804 81 common/cmd_net.c NetLoop() back without error
1805 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1806 82 common/cmd_net.c trying automatic boot
1807 83 common/cmd_net.c running autoscript
1808 -83 common/cmd_net.c some error in automatic boot or autoscript
1809 84 common/cmd_net.c end without errors
1814 100 common/cmd_bootm.c Kernel FIT Image has correct format
1815 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1816 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1817 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1818 102 common/cmd_bootm.c Kernel unit name specified
1819 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1820 103 common/cmd_bootm.c Found configuration node
1821 104 common/cmd_bootm.c Got kernel subimage node offset
1822 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1823 105 common/cmd_bootm.c Kernel subimage hash verification OK
1824 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1825 106 common/cmd_bootm.c Architecture check OK
1826 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1827 107 common/cmd_bootm.c Kernel subimge type OK
1828 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1829 108 common/cmd_bootm.c Got kernel subimage data/size
1830 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1831 -109 common/cmd_bootm.c Can't get kernel subimage type
1832 -110 common/cmd_bootm.c Can't get kernel subimage comp
1833 -111 common/cmd_bootm.c Can't get kernel subimage os
1834 -112 common/cmd_bootm.c Can't get kernel subimage load address
1835 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1837 120 common/image.c Start initial ramdisk verification
1838 -120 common/image.c Ramdisk FIT image has incorrect format
1839 121 common/image.c Ramdisk FIT image has correct format
1840 122 common/image.c No Ramdisk subimage unit name, using configuration
1841 -122 common/image.c Can't get configuration for ramdisk subimage
1842 123 common/image.c Ramdisk unit name specified
1843 -124 common/image.c Can't get ramdisk subimage node offset
1844 125 common/image.c Got ramdisk subimage node offset
1845 -125 common/image.c Ramdisk subimage hash verification failed
1846 126 common/image.c Ramdisk subimage hash verification OK
1847 -126 common/image.c Ramdisk subimage for unsupported architecture
1848 127 common/image.c Architecture check OK
1849 -127 common/image.c Can't get ramdisk subimage data/size
1850 128 common/image.c Got ramdisk subimage data/size
1851 129 common/image.c Can't get ramdisk load address
1852 -129 common/image.c Got ramdisk load address
1854 -130 common/cmd_doc.c Icorrect FIT image format
1855 131 common/cmd_doc.c FIT image format OK
1857 -140 common/cmd_ide.c Icorrect FIT image format
1858 141 common/cmd_ide.c FIT image format OK
1860 -150 common/cmd_nand.c Icorrect FIT image format
1861 151 common/cmd_nand.c FIT image format OK
1867 [so far only for SMDK2400 and TRAB boards]
1869 - Modem support endable:
1870 CONFIG_MODEM_SUPPORT
1872 - RTS/CTS Flow control enable:
1875 - Modem debug support:
1876 CONFIG_MODEM_SUPPORT_DEBUG
1878 Enables debugging stuff (char screen[1024], dbg())
1879 for modem support. Useful only with BDI2000.
1881 - Interrupt support (PPC):
1883 There are common interrupt_init() and timer_interrupt()
1884 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1885 for cpu specific initialization. interrupt_init_cpu()
1886 should set decrementer_count to appropriate value. If
1887 cpu resets decrementer automatically after interrupt
1888 (ppc4xx) it should set decrementer_count to zero.
1889 timer_interrupt() calls timer_interrupt_cpu() for cpu
1890 specific handling. If board has watchdog / status_led
1891 / other_activity_monitor it works automatically from
1892 general timer_interrupt().
1896 In the target system modem support is enabled when a
1897 specific key (key combination) is pressed during
1898 power-on. Otherwise U-Boot will boot normally
1899 (autoboot). The key_pressed() fuction is called from
1900 board_init(). Currently key_pressed() is a dummy
1901 function, returning 1 and thus enabling modem
1904 If there are no modem init strings in the
1905 environment, U-Boot proceed to autoboot; the
1906 previous output (banner, info printfs) will be
1909 See also: doc/README.Modem
1912 Configuration Settings:
1913 -----------------------
1915 - CFG_LONGHELP: Defined when you want long help messages included;
1916 undefine this when you're short of memory.
1918 - CFG_PROMPT: This is what U-Boot prints on the console to
1919 prompt for user input.
1921 - CFG_CBSIZE: Buffer size for input from the Console
1923 - CFG_PBSIZE: Buffer size for Console output
1925 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1927 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1928 the application (usually a Linux kernel) when it is
1931 - CFG_BAUDRATE_TABLE:
1932 List of legal baudrate settings for this board.
1934 - CFG_CONSOLE_INFO_QUIET
1935 Suppress display of console information at boot.
1937 - CFG_CONSOLE_IS_IN_ENV
1938 If the board specific function
1939 extern int overwrite_console (void);
1940 returns 1, the stdin, stderr and stdout are switched to the
1941 serial port, else the settings in the environment are used.
1943 - CFG_CONSOLE_OVERWRITE_ROUTINE
1944 Enable the call to overwrite_console().
1946 - CFG_CONSOLE_ENV_OVERWRITE
1947 Enable overwrite of previous console environment settings.
1949 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1950 Begin and End addresses of the area used by the
1954 Enable an alternate, more extensive memory test.
1956 - CFG_MEMTEST_SCRATCH:
1957 Scratch address used by the alternate memory test
1958 You only need to set this if address zero isn't writeable
1960 - CFG_MEM_TOP_HIDE (PPC only):
1961 If CFG_MEM_TOP_HIDE is defined in the board config header,
1962 this specified memory area will get subtracted from the top
1963 (end) of ram and won't get "touched" at all by U-Boot. By
1964 fixing up gd->ram_size the Linux kernel should gets passed
1965 the now "corrected" memory size and won't touch it either.
1966 This should work for arch/ppc and arch/powerpc. Only Linux
1967 board ports in arch/powerpc with bootwrapper support that
1968 recalculate the memory size from the SDRAM controller setup
1969 will have to get fixed in Linux additionally.
1971 This option can be used as a workaround for the 440EPx/GRx
1972 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1975 WARNING: Please make sure that this value is a multiple of
1976 the Linux page size (normally 4k). If this is not the case,
1977 then the end address of the Linux memory will be located at a
1978 non page size aligned address and this could cause major
1981 - CFG_TFTP_LOADADDR:
1982 Default load address for network file downloads
1984 - CFG_LOADS_BAUD_CHANGE:
1985 Enable temporary baudrate change while serial download
1988 Physical start address of SDRAM. _Must_ be 0 here.
1991 Physical start address of Motherboard I/O (if using a
1995 Physical start address of Flash memory.
1998 Physical start address of boot monitor code (set by
1999 make config files to be same as the text base address
2000 (TEXT_BASE) used when linking) - same as
2001 CFG_FLASH_BASE when booting from flash.
2004 Size of memory reserved for monitor code, used to
2005 determine _at_compile_time_ (!) if the environment is
2006 embedded within the U-Boot image, or in a separate
2010 Size of DRAM reserved for malloc() use.
2013 Normally compressed uImages are limited to an
2014 uncompressed size of 8 MBytes. If this is not enough,
2015 you can define CFG_BOOTM_LEN in your board config file
2016 to adjust this setting to your needs.
2019 Maximum size of memory mapped by the startup code of
2020 the Linux kernel; all data that must be processed by
2021 the Linux kernel (bd_info, boot arguments, FDT blob if
2022 used) must be put below this limit, unless "bootm_low"
2023 enviroment variable is defined and non-zero. In such case
2024 all data for the Linux kernel must be between "bootm_low"
2025 and "bootm_low" + CFG_BOOTMAPSZ.
2027 - CFG_MAX_FLASH_BANKS:
2028 Max number of Flash memory banks
2030 - CFG_MAX_FLASH_SECT:
2031 Max number of sectors on a Flash chip
2033 - CFG_FLASH_ERASE_TOUT:
2034 Timeout for Flash erase operations (in ms)
2036 - CFG_FLASH_WRITE_TOUT:
2037 Timeout for Flash write operations (in ms)
2039 - CFG_FLASH_LOCK_TOUT
2040 Timeout for Flash set sector lock bit operation (in ms)
2042 - CFG_FLASH_UNLOCK_TOUT
2043 Timeout for Flash clear lock bits operation (in ms)
2045 - CFG_FLASH_PROTECTION
2046 If defined, hardware flash sectors protection is used
2047 instead of U-Boot software protection.
2049 - CFG_DIRECT_FLASH_TFTP:
2051 Enable TFTP transfers directly to flash memory;
2052 without this option such a download has to be
2053 performed in two steps: (1) download to RAM, and (2)
2054 copy from RAM to flash.
2056 The two-step approach is usually more reliable, since
2057 you can check if the download worked before you erase
2058 the flash, but in some situations (when sytem RAM is
2059 too limited to allow for a tempory copy of the
2060 downloaded image) this option may be very useful.
2063 Define if the flash driver uses extra elements in the
2064 common flash structure for storing flash geometry.
2066 - CFG_FLASH_CFI_DRIVER
2067 This option also enables the building of the cfi_flash driver
2068 in the drivers directory
2070 - CFG_FLASH_USE_BUFFER_WRITE
2071 Use buffered writes to flash.
2073 - CONFIG_FLASH_SPANSION_S29WS_N
2074 s29ws-n MirrorBit flash has non-standard addresses for buffered
2077 - CFG_FLASH_QUIET_TEST
2078 If this option is defined, the common CFI flash doesn't
2079 print it's warning upon not recognized FLASH banks. This
2080 is useful, if some of the configured banks are only
2081 optionally available.
2083 - CONFIG_FLASH_SHOW_PROGRESS
2084 If defined (must be an integer), print out countdown
2085 digits and dots. Recommended value: 45 (9..1) for 80
2086 column displays, 15 (3..1) for 40 column displays.
2088 - CFG_RX_ETH_BUFFER:
2089 Defines the number of ethernet receive buffers. On some
2090 ethernet controllers it is recommended to set this value
2091 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2092 buffers can be full shortly after enabling the interface
2093 on high ethernet traffic.
2094 Defaults to 4 if not defined.
2096 The following definitions that deal with the placement and management
2097 of environment data (variable area); in general, we support the
2098 following configurations:
2100 - CFG_ENV_IS_IN_FLASH:
2102 Define this if the environment is in flash memory.
2104 a) The environment occupies one whole flash sector, which is
2105 "embedded" in the text segment with the U-Boot code. This
2106 happens usually with "bottom boot sector" or "top boot
2107 sector" type flash chips, which have several smaller
2108 sectors at the start or the end. For instance, such a
2109 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2110 such a case you would place the environment in one of the
2111 4 kB sectors - with U-Boot code before and after it. With
2112 "top boot sector" type flash chips, you would put the
2113 environment in one of the last sectors, leaving a gap
2114 between U-Boot and the environment.
2118 Offset of environment data (variable area) to the
2119 beginning of flash memory; for instance, with bottom boot
2120 type flash chips the second sector can be used: the offset
2121 for this sector is given here.
2123 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2127 This is just another way to specify the start address of
2128 the flash sector containing the environment (instead of
2131 - CFG_ENV_SECT_SIZE:
2133 Size of the sector containing the environment.
2136 b) Sometimes flash chips have few, equal sized, BIG sectors.
2137 In such a case you don't want to spend a whole sector for
2142 If you use this in combination with CFG_ENV_IS_IN_FLASH
2143 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2144 of this flash sector for the environment. This saves
2145 memory for the RAM copy of the environment.
2147 It may also save flash memory if you decide to use this
2148 when your environment is "embedded" within U-Boot code,
2149 since then the remainder of the flash sector could be used
2150 for U-Boot code. It should be pointed out that this is
2151 STRONGLY DISCOURAGED from a robustness point of view:
2152 updating the environment in flash makes it always
2153 necessary to erase the WHOLE sector. If something goes
2154 wrong before the contents has been restored from a copy in
2155 RAM, your target system will be dead.
2157 - CFG_ENV_ADDR_REDUND
2160 These settings describe a second storage area used to hold
2161 a redundand copy of the environment data, so that there is
2162 a valid backup copy in case there is a power failure during
2163 a "saveenv" operation.
2165 BE CAREFUL! Any changes to the flash layout, and some changes to the
2166 source code will make it necessary to adapt <board>/u-boot.lds*
2170 - CFG_ENV_IS_IN_NVRAM:
2172 Define this if you have some non-volatile memory device
2173 (NVRAM, battery buffered SRAM) which you want to use for the
2179 These two #defines are used to determin the memory area you
2180 want to use for environment. It is assumed that this memory
2181 can just be read and written to, without any special
2184 BE CAREFUL! The first access to the environment happens quite early
2185 in U-Boot initalization (when we try to get the setting of for the
2186 console baudrate). You *MUST* have mappend your NVRAM area then, or
2189 Please note that even with NVRAM we still use a copy of the
2190 environment in RAM: we could work on NVRAM directly, but we want to
2191 keep settings there always unmodified except somebody uses "saveenv"
2192 to save the current settings.
2195 - CFG_ENV_IS_IN_EEPROM:
2197 Use this if you have an EEPROM or similar serial access
2198 device and a driver for it.
2203 These two #defines specify the offset and size of the
2204 environment area within the total memory of your EEPROM.
2206 - CFG_I2C_EEPROM_ADDR:
2207 If defined, specified the chip address of the EEPROM device.
2208 The default address is zero.
2210 - CFG_EEPROM_PAGE_WRITE_BITS:
2211 If defined, the number of bits used to address bytes in a
2212 single page in the EEPROM device. A 64 byte page, for example
2213 would require six bits.
2215 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2216 If defined, the number of milliseconds to delay between
2217 page writes. The default is zero milliseconds.
2219 - CFG_I2C_EEPROM_ADDR_LEN:
2220 The length in bytes of the EEPROM memory array address. Note
2221 that this is NOT the chip address length!
2223 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2224 EEPROM chips that implement "address overflow" are ones
2225 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2226 address and the extra bits end up in the "chip address" bit
2227 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2230 Note that we consider the length of the address field to
2231 still be one byte because the extra address bits are hidden
2232 in the chip address.
2235 The size in bytes of the EEPROM device.
2238 - CFG_ENV_IS_IN_DATAFLASH:
2240 Define this if you have a DataFlash memory device which you
2241 want to use for the environment.
2247 These three #defines specify the offset and size of the
2248 environment area within the total memory of your DataFlash placed
2249 at the specified address.
2251 - CFG_ENV_IS_IN_NAND:
2253 Define this if you have a NAND device which you want to use
2254 for the environment.
2259 These two #defines specify the offset and size of the environment
2260 area within the first NAND device.
2262 - CFG_ENV_OFFSET_REDUND
2264 This setting describes a second storage area of CFG_ENV_SIZE
2265 size used to hold a redundant copy of the environment data,
2266 so that there is a valid backup copy in case there is a
2267 power failure during a "saveenv" operation.
2269 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2270 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2271 the NAND devices block size.
2273 - CFG_SPI_INIT_OFFSET
2275 Defines offset to the initial SPI buffer area in DPRAM. The
2276 area is used at an early stage (ROM part) if the environment
2277 is configured to reside in the SPI EEPROM: We need a 520 byte
2278 scratch DPRAM area. It is used between the two initialization
2279 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2280 to be a good choice since it makes it far enough from the
2281 start of the data area as well as from the stack pointer.
2283 Please note that the environment is read-only until the monitor
2284 has been relocated to RAM and a RAM copy of the environment has been
2285 created; also, when using EEPROM you will have to use getenv_r()
2286 until then to read environment variables.
2288 The environment is protected by a CRC32 checksum. Before the monitor
2289 is relocated into RAM, as a result of a bad CRC you will be working
2290 with the compiled-in default environment - *silently*!!! [This is
2291 necessary, because the first environment variable we need is the
2292 "baudrate" setting for the console - if we have a bad CRC, we don't
2293 have any device yet where we could complain.]
2295 Note: once the monitor has been relocated, then it will complain if
2296 the default environment is used; a new CRC is computed as soon as you
2297 use the "saveenv" command to store a valid environment.
2299 - CFG_FAULT_ECHO_LINK_DOWN:
2300 Echo the inverted Ethernet link state to the fault LED.
2302 Note: If this option is active, then CFG_FAULT_MII_ADDR
2303 also needs to be defined.
2305 - CFG_FAULT_MII_ADDR:
2306 MII address of the PHY to check for the Ethernet link state.
2308 - CFG_64BIT_VSPRINTF:
2309 Makes vsprintf (and all *printf functions) support printing
2310 of 64bit values by using the L quantifier
2312 - CFG_64BIT_STRTOUL:
2313 Adds simple_strtoull that returns a 64bit value
2315 Low Level (hardware related) configuration options:
2316 ---------------------------------------------------
2318 - CFG_CACHELINE_SIZE:
2319 Cache Line Size of the CPU.
2322 Default address of the IMMR after system reset.
2324 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2325 and RPXsuper) to be able to adjust the position of
2326 the IMMR register after a reset.
2328 - Floppy Disk Support:
2329 CFG_FDC_DRIVE_NUMBER
2331 the default drive number (default value 0)
2335 defines the spacing between fdc chipset registers
2340 defines the offset of register from address. It
2341 depends on which part of the data bus is connected to
2342 the fdc chipset. (default value 0)
2344 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2345 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2348 if CFG_FDC_HW_INIT is defined, then the function
2349 fdc_hw_init() is called at the beginning of the FDC
2350 setup. fdc_hw_init() must be provided by the board
2351 source code. It is used to make hardware dependant
2354 - CFG_IMMR: Physical address of the Internal Memory.
2355 DO NOT CHANGE unless you know exactly what you're
2356 doing! (11-4) [MPC8xx/82xx systems only]
2358 - CFG_INIT_RAM_ADDR:
2360 Start address of memory area that can be used for
2361 initial data and stack; please note that this must be
2362 writable memory that is working WITHOUT special
2363 initialization, i. e. you CANNOT use normal RAM which
2364 will become available only after programming the
2365 memory controller and running certain initialization
2368 U-Boot uses the following memory types:
2369 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2370 - MPC824X: data cache
2371 - PPC4xx: data cache
2373 - CFG_GBL_DATA_OFFSET:
2375 Offset of the initial data structure in the memory
2376 area defined by CFG_INIT_RAM_ADDR. Usually
2377 CFG_GBL_DATA_OFFSET is chosen such that the initial
2378 data is located at the end of the available space
2379 (sometimes written as (CFG_INIT_RAM_END -
2380 CFG_INIT_DATA_SIZE), and the initial stack is just
2381 below that area (growing from (CFG_INIT_RAM_ADDR +
2382 CFG_GBL_DATA_OFFSET) downward.
2385 On the MPC824X (or other systems that use the data
2386 cache for initial memory) the address chosen for
2387 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2388 point to an otherwise UNUSED address space between
2389 the top of RAM and the start of the PCI space.
2391 - CFG_SIUMCR: SIU Module Configuration (11-6)
2393 - CFG_SYPCR: System Protection Control (11-9)
2395 - CFG_TBSCR: Time Base Status and Control (11-26)
2397 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2399 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2401 - CFG_SCCR: System Clock and reset Control Register (15-27)
2403 - CFG_OR_TIMING_SDRAM:
2407 periodic timer for refresh
2409 - CFG_DER: Debug Event Register (37-47)
2411 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2412 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2413 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2415 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2417 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2418 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2419 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2420 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2422 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2423 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2424 Machine Mode Register and Memory Periodic Timer
2425 Prescaler definitions (SDRAM timing)
2427 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2428 enable I2C microcode relocation patch (MPC8xx);
2429 define relocation offset in DPRAM [DSP2]
2431 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2432 enable SMC microcode relocation patch (MPC8xx);
2433 define relocation offset in DPRAM [SMC1]
2435 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2436 enable SPI microcode relocation patch (MPC8xx);
2437 define relocation offset in DPRAM [SCC4]
2440 Use OSCM clock mode on MBX8xx board. Be careful,
2441 wrong setting might damage your board. Read
2442 doc/README.MBX before setting this variable!
2444 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2445 Offset of the bootmode word in DPRAM used by post
2446 (Power On Self Tests). This definition overrides
2447 #define'd default value in commproc.h resp.
2450 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2451 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2452 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2453 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2454 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2455 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2456 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2457 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2458 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2461 Get DDR timing information from an I2C EEPROM. Common
2462 with pluggable memory modules such as SODIMMs
2465 I2C address of the SPD EEPROM
2468 If SPD EEPROM is on an I2C bus other than the first
2469 one, specify here. Note that the value must resolve
2470 to something your driver can deal with.
2472 - CFG_83XX_DDR_USES_CS0
2473 Only for 83xx systems. If specified, then DDR should
2474 be configured using CS0 and CS1 instead of CS2 and CS3.
2476 - CFG_83XX_DDR_USES_CS0
2477 Only for 83xx systems. If specified, then DDR should
2478 be configured using CS0 and CS1 instead of CS2 and CS3.
2480 - CONFIG_ETHER_ON_FEC[12]
2481 Define to enable FEC[12] on a 8xx series processor.
2483 - CONFIG_FEC[12]_PHY
2484 Define to the hardcoded PHY address which corresponds
2485 to the given FEC; i. e.
2486 #define CONFIG_FEC1_PHY 4
2487 means that the PHY with address 4 is connected to FEC1
2489 When set to -1, means to probe for first available.
2491 - CONFIG_FEC[12]_PHY_NORXERR
2492 The PHY does not have a RXERR line (RMII only).
2493 (so program the FEC to ignore it).
2496 Enable RMII mode for all FECs.
2497 Note that this is a global option, we can't
2498 have one FEC in standard MII mode and another in RMII mode.
2500 - CONFIG_CRC32_VERIFY
2501 Add a verify option to the crc32 command.
2504 => crc32 -v <address> <count> <crc32>
2506 Where address/count indicate a memory area
2507 and crc32 is the correct crc32 which the
2511 Add the "loopw" memory command. This only takes effect if
2512 the memory commands are activated globally (CONFIG_CMD_MEM).
2515 Add the "mdc" and "mwc" memory commands. These are cyclic
2520 This command will print 4 bytes (10,11,12,13) each 500 ms.
2522 => mwc.l 100 12345678 10
2523 This command will write 12345678 to address 100 all 10 ms.
2525 This only takes effect if the memory commands are activated
2526 globally (CONFIG_CMD_MEM).
2528 - CONFIG_SKIP_LOWLEVEL_INIT
2529 - CONFIG_SKIP_RELOCATE_UBOOT
2531 [ARM only] If these variables are defined, then
2532 certain low level initializations (like setting up
2533 the memory controller) are omitted and/or U-Boot does
2534 not relocate itself into RAM.
2535 Normally these variables MUST NOT be defined. The
2536 only exception is when U-Boot is loaded (to RAM) by
2537 some other boot loader or by a debugger which
2538 performs these intializations itself.
2541 Building the Software:
2542 ======================
2544 Building U-Boot has been tested in several native build environments
2545 and in many different cross environments. Of course we cannot support
2546 all possibly existing versions of cross development tools in all
2547 (potentially obsolete) versions. In case of tool chain problems we
2548 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2549 which is extensively used to build and test U-Boot.
2551 If you are not using a native environment, it is assumed that you
2552 have GNU cross compiling tools available in your path. In this case,
2553 you must set the environment variable CROSS_COMPILE in your shell.
2554 Note that no changes to the Makefile or any other source files are
2555 necessary. For example using the ELDK on a 4xx CPU, please enter:
2557 $ CROSS_COMPILE=ppc_4xx-
2558 $ export CROSS_COMPILE
2560 U-Boot is intended to be simple to build. After installing the
2561 sources you must configure U-Boot for one specific board type. This
2566 where "NAME_config" is the name of one of the existing configu-
2567 rations; see the main Makefile for supported names.
2569 Note: for some board special configuration names may exist; check if
2570 additional information is available from the board vendor; for
2571 instance, the TQM823L systems are available without (standard)
2572 or with LCD support. You can select such additional "features"
2573 when chosing the configuration, i. e.
2576 - will configure for a plain TQM823L, i. e. no LCD support
2578 make TQM823L_LCD_config
2579 - will configure for a TQM823L with U-Boot console on LCD
2584 Finally, type "make all", and you should get some working U-Boot
2585 images ready for download to / installation on your system:
2587 - "u-boot.bin" is a raw binary image
2588 - "u-boot" is an image in ELF binary format
2589 - "u-boot.srec" is in Motorola S-Record format
2591 By default the build is performed locally and the objects are saved
2592 in the source directory. One of the two methods can be used to change
2593 this behavior and build U-Boot to some external directory:
2595 1. Add O= to the make command line invocations:
2597 make O=/tmp/build distclean
2598 make O=/tmp/build NAME_config
2599 make O=/tmp/build all
2601 2. Set environment variable BUILD_DIR to point to the desired location:
2603 export BUILD_DIR=/tmp/build
2608 Note that the command line "O=" setting overrides the BUILD_DIR environment
2612 Please be aware that the Makefiles assume you are using GNU make, so
2613 for instance on NetBSD you might need to use "gmake" instead of
2617 If the system board that you have is not listed, then you will need
2618 to port U-Boot to your hardware platform. To do this, follow these
2621 1. Add a new configuration option for your board to the toplevel
2622 "Makefile" and to the "MAKEALL" script, using the existing
2623 entries as examples. Note that here and at many other places
2624 boards and other names are listed in alphabetical sort order. Please
2626 2. Create a new directory to hold your board specific code. Add any
2627 files you need. In your board directory, you will need at least
2628 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2629 3. Create a new configuration file "include/configs/<board>.h" for
2631 3. If you're porting U-Boot to a new CPU, then also create a new
2632 directory to hold your CPU specific code. Add any files you need.
2633 4. Run "make <board>_config" with your new name.
2634 5. Type "make", and you should get a working "u-boot.srec" file
2635 to be installed on your target system.
2636 6. Debug and solve any problems that might arise.
2637 [Of course, this last step is much harder than it sounds.]
2640 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2641 ==============================================================
2643 If you have modified U-Boot sources (for instance added a new board
2644 or support for new devices, a new CPU, etc.) you are expected to
2645 provide feedback to the other developers. The feedback normally takes
2646 the form of a "patch", i. e. a context diff against a certain (latest
2647 official or latest in the git repository) version of U-Boot sources.
2649 But before you submit such a patch, please verify that your modifi-
2650 cation did not break existing code. At least make sure that *ALL* of
2651 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2652 just run the "MAKEALL" script, which will configure and build U-Boot
2653 for ALL supported system. Be warned, this will take a while. You can
2654 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2655 environment variable to the script, i. e. to use the ELDK cross tools
2658 CROSS_COMPILE=ppc_8xx- MAKEALL
2660 or to build on a native PowerPC system you can type
2662 CROSS_COMPILE=' ' MAKEALL
2664 When using the MAKEALL script, the default behaviour is to build
2665 U-Boot in the source directory. This location can be changed by
2666 setting the BUILD_DIR environment variable. Also, for each target
2667 built, the MAKEALL script saves two log files (<target>.ERR and
2668 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2669 location can be changed by setting the MAKEALL_LOGDIR environment
2670 variable. For example:
2672 export BUILD_DIR=/tmp/build
2673 export MAKEALL_LOGDIR=/tmp/log
2674 CROSS_COMPILE=ppc_8xx- MAKEALL
2676 With the above settings build objects are saved in the /tmp/build,
2677 log files are saved in the /tmp/log and the source tree remains clean
2678 during the whole build process.
2681 See also "U-Boot Porting Guide" below.
2684 Monitor Commands - Overview:
2685 ============================
2687 go - start application at address 'addr'
2688 run - run commands in an environment variable
2689 bootm - boot application image from memory
2690 bootp - boot image via network using BootP/TFTP protocol
2691 tftpboot- boot image via network using TFTP protocol
2692 and env variables "ipaddr" and "serverip"
2693 (and eventually "gatewayip")
2694 rarpboot- boot image via network using RARP/TFTP protocol
2695 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2696 loads - load S-Record file over serial line
2697 loadb - load binary file over serial line (kermit mode)
2699 mm - memory modify (auto-incrementing)
2700 nm - memory modify (constant address)
2701 mw - memory write (fill)
2703 cmp - memory compare
2704 crc32 - checksum calculation
2705 imd - i2c memory display
2706 imm - i2c memory modify (auto-incrementing)
2707 inm - i2c memory modify (constant address)
2708 imw - i2c memory write (fill)
2709 icrc32 - i2c checksum calculation
2710 iprobe - probe to discover valid I2C chip addresses
2711 iloop - infinite loop on address range
2712 isdram - print SDRAM configuration information
2713 sspi - SPI utility commands
2714 base - print or set address offset
2715 printenv- print environment variables
2716 setenv - set environment variables
2717 saveenv - save environment variables to persistent storage
2718 protect - enable or disable FLASH write protection
2719 erase - erase FLASH memory
2720 flinfo - print FLASH memory information
2721 bdinfo - print Board Info structure
2722 iminfo - print header information for application image
2723 coninfo - print console devices and informations
2724 ide - IDE sub-system
2725 loop - infinite loop on address range
2726 loopw - infinite write loop on address range
2727 mtest - simple RAM test
2728 icache - enable or disable instruction cache
2729 dcache - enable or disable data cache
2730 reset - Perform RESET of the CPU
2731 echo - echo args to console
2732 version - print monitor version
2733 help - print online help
2734 ? - alias for 'help'
2737 Monitor Commands - Detailed Description:
2738 ========================================
2742 For now: just type "help <command>".
2745 Environment Variables:
2746 ======================
2748 U-Boot supports user configuration using Environment Variables which
2749 can be made persistent by saving to Flash memory.
2751 Environment Variables are set using "setenv", printed using
2752 "printenv", and saved to Flash using "saveenv". Using "setenv"
2753 without a value can be used to delete a variable from the
2754 environment. As long as you don't save the environment you are
2755 working with an in-memory copy. In case the Flash area containing the
2756 environment is erased by accident, a default environment is provided.
2758 Some configuration options can be set using Environment Variables:
2760 baudrate - see CONFIG_BAUDRATE
2762 bootdelay - see CONFIG_BOOTDELAY
2764 bootcmd - see CONFIG_BOOTCOMMAND
2766 bootargs - Boot arguments when booting an RTOS image
2768 bootfile - Name of the image to load with TFTP
2770 bootm_low - Memory range available for image processing in the bootm
2771 command can be restricted. This variable is given as
2772 a hexadecimal number and defines lowest address allowed
2773 for use by the bootm command. See also "bootm_size"
2774 environment variable. Address defined by "bootm_low" is
2775 also the base of the initial memory mapping for the Linux
2776 kernel -- see the descripton of CFG_BOOTMAPSZ.
2778 bootm_size - Memory range available for image processing in the bootm
2779 command can be restricted. This variable is given as
2780 a hexadecimal number and defines the size of the region
2781 allowed for use by the bootm command. See also "bootm_low"
2782 environment variable.
2784 autoload - if set to "no" (any string beginning with 'n'),
2785 "bootp" will just load perform a lookup of the
2786 configuration from the BOOTP server, but not try to
2787 load any image using TFTP
2789 autoscript - if set to "yes" commands like "loadb", "loady",
2790 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2791 to automatically run script images (by internally
2792 calling "autoscript").
2794 autoscript_uname - if script image is in a format (FIT) this
2795 variable is used to get script subimage unit name.
2797 autostart - if set to "yes", an image loaded using the "bootp",
2798 "rarpboot", "tftpboot" or "diskboot" commands will
2799 be automatically started (by internally calling
2802 If set to "no", a standalone image passed to the
2803 "bootm" command will be copied to the load address
2804 (and eventually uncompressed), but NOT be started.
2805 This can be used to load and uncompress arbitrary
2808 i2cfast - (PPC405GP|PPC405EP only)
2809 if set to 'y' configures Linux I2C driver for fast
2810 mode (400kHZ). This environment variable is used in
2811 initialization code. So, for changes to be effective
2812 it must be saved and board must be reset.
2814 initrd_high - restrict positioning of initrd images:
2815 If this variable is not set, initrd images will be
2816 copied to the highest possible address in RAM; this
2817 is usually what you want since it allows for
2818 maximum initrd size. If for some reason you want to
2819 make sure that the initrd image is loaded below the
2820 CFG_BOOTMAPSZ limit, you can set this environment
2821 variable to a value of "no" or "off" or "0".
2822 Alternatively, you can set it to a maximum upper
2823 address to use (U-Boot will still check that it
2824 does not overwrite the U-Boot stack and data).
2826 For instance, when you have a system with 16 MB
2827 RAM, and want to reserve 4 MB from use by Linux,
2828 you can do this by adding "mem=12M" to the value of
2829 the "bootargs" variable. However, now you must make
2830 sure that the initrd image is placed in the first
2831 12 MB as well - this can be done with
2833 setenv initrd_high 00c00000
2835 If you set initrd_high to 0xFFFFFFFF, this is an
2836 indication to U-Boot that all addresses are legal
2837 for the Linux kernel, including addresses in flash
2838 memory. In this case U-Boot will NOT COPY the
2839 ramdisk at all. This may be useful to reduce the
2840 boot time on your system, but requires that this
2841 feature is supported by your Linux kernel.
2843 ipaddr - IP address; needed for tftpboot command
2845 loadaddr - Default load address for commands like "bootp",
2846 "rarpboot", "tftpboot", "loadb" or "diskboot"
2848 loads_echo - see CONFIG_LOADS_ECHO
2850 serverip - TFTP server IP address; needed for tftpboot command
2852 bootretry - see CONFIG_BOOT_RETRY_TIME
2854 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2856 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2858 ethprime - When CONFIG_NET_MULTI is enabled controls which
2859 interface is used first.
2861 ethact - When CONFIG_NET_MULTI is enabled controls which
2862 interface is currently active. For example you
2863 can do the following
2865 => setenv ethact FEC ETHERNET
2866 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2867 => setenv ethact SCC ETHERNET
2868 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2870 ethrotate - When set to "no" U-Boot does not go through all
2871 available network interfaces.
2872 It just stays at the currently selected interface.
2874 netretry - When set to "no" each network operation will
2875 either succeed or fail without retrying.
2876 When set to "once" the network operation will
2877 fail when all the available network interfaces
2878 are tried once without success.
2879 Useful on scripts which control the retry operation
2882 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2883 if set load address for the npe microcode
2885 tftpsrcport - If this is set, the value is used for TFTP's
2888 tftpdstport - If this is set, the value is used for TFTP's UDP
2889 destination port instead of the Well Know Port 69.
2891 vlan - When set to a value < 4095 the traffic over
2892 ethernet is encapsulated/received over 802.1q
2895 The following environment variables may be used and automatically
2896 updated by the network boot commands ("bootp" and "rarpboot"),
2897 depending the information provided by your boot server:
2899 bootfile - see above
2900 dnsip - IP address of your Domain Name Server
2901 dnsip2 - IP address of your secondary Domain Name Server
2902 gatewayip - IP address of the Gateway (Router) to use
2903 hostname - Target hostname
2905 netmask - Subnet Mask
2906 rootpath - Pathname of the root filesystem on the NFS server
2907 serverip - see above
2910 There are two special Environment Variables:
2912 serial# - contains hardware identification information such
2913 as type string and/or serial number
2914 ethaddr - Ethernet address
2916 These variables can be set only once (usually during manufacturing of
2917 the board). U-Boot refuses to delete or overwrite these variables
2918 once they have been set once.
2921 Further special Environment Variables:
2923 ver - Contains the U-Boot version string as printed
2924 with the "version" command. This variable is
2925 readonly (see CONFIG_VERSION_VARIABLE).
2928 Please note that changes to some configuration parameters may take
2929 only effect after the next boot (yes, that's just like Windoze :-).
2932 Command Line Parsing:
2933 =====================
2935 There are two different command line parsers available with U-Boot:
2936 the old "simple" one, and the much more powerful "hush" shell:
2938 Old, simple command line parser:
2939 --------------------------------
2941 - supports environment variables (through setenv / saveenv commands)
2942 - several commands on one line, separated by ';'
2943 - variable substitution using "... ${name} ..." syntax
2944 - special characters ('$', ';') can be escaped by prefixing with '\',
2946 setenv bootcmd bootm \${address}
2947 - You can also escape text by enclosing in single apostrophes, for example:
2948 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2953 - similar to Bourne shell, with control structures like
2954 if...then...else...fi, for...do...done; while...do...done,
2955 until...do...done, ...
2956 - supports environment ("global") variables (through setenv / saveenv
2957 commands) and local shell variables (through standard shell syntax
2958 "name=value"); only environment variables can be used with "run"
2964 (1) If a command line (or an environment variable executed by a "run"
2965 command) contains several commands separated by semicolon, and
2966 one of these commands fails, then the remaining commands will be
2969 (2) If you execute several variables with one call to run (i. e.
2970 calling run with a list af variables as arguments), any failing
2971 command will cause "run" to terminate, i. e. the remaining
2972 variables are not executed.
2974 Note for Redundant Ethernet Interfaces:
2975 =======================================
2977 Some boards come with redundant ethernet interfaces; U-Boot supports
2978 such configurations and is capable of automatic selection of a
2979 "working" interface when needed. MAC assignment works as follows:
2981 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2982 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2983 "eth1addr" (=>eth1), "eth2addr", ...
2985 If the network interface stores some valid MAC address (for instance
2986 in SROM), this is used as default address if there is NO correspon-
2987 ding setting in the environment; if the corresponding environment
2988 variable is set, this overrides the settings in the card; that means:
2990 o If the SROM has a valid MAC address, and there is no address in the
2991 environment, the SROM's address is used.
2993 o If there is no valid address in the SROM, and a definition in the
2994 environment exists, then the value from the environment variable is
2997 o If both the SROM and the environment contain a MAC address, and
2998 both addresses are the same, this MAC address is used.
3000 o If both the SROM and the environment contain a MAC address, and the
3001 addresses differ, the value from the environment is used and a
3004 o If neither SROM nor the environment contain a MAC address, an error
3011 U-Boot is capable of booting (and performing other auxiliary operations on)
3012 images in two formats:
3014 New uImage format (FIT)
3015 -----------------------
3017 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3018 to Flattened Device Tree). It allows the use of images with multiple
3019 components (several kernels, ramdisks, etc.), with contents protected by
3020 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3026 Old image format is based on binary files which can be basically anything,
3027 preceded by a special header; see the definitions in include/image.h for
3028 details; basically, the header defines the following image properties:
3030 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3031 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3032 LynxOS, pSOS, QNX, RTEMS, ARTOS;
3033 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
3034 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3035 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3036 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3037 * Compression Type (uncompressed, gzip, bzip2)
3043 The header is marked by a special Magic Number, and both the header
3044 and the data portions of the image are secured against corruption by
3051 Although U-Boot should support any OS or standalone application
3052 easily, the main focus has always been on Linux during the design of
3055 U-Boot includes many features that so far have been part of some
3056 special "boot loader" code within the Linux kernel. Also, any
3057 "initrd" images to be used are no longer part of one big Linux image;
3058 instead, kernel and "initrd" are separate images. This implementation
3059 serves several purposes:
3061 - the same features can be used for other OS or standalone
3062 applications (for instance: using compressed images to reduce the
3063 Flash memory footprint)
3065 - it becomes much easier to port new Linux kernel versions because
3066 lots of low-level, hardware dependent stuff are done by U-Boot
3068 - the same Linux kernel image can now be used with different "initrd"
3069 images; of course this also means that different kernel images can
3070 be run with the same "initrd". This makes testing easier (you don't
3071 have to build a new "zImage.initrd" Linux image when you just
3072 change a file in your "initrd"). Also, a field-upgrade of the
3073 software is easier now.
3079 Porting Linux to U-Boot based systems:
3080 ---------------------------------------
3082 U-Boot cannot save you from doing all the necessary modifications to
3083 configure the Linux device drivers for use with your target hardware
3084 (no, we don't intend to provide a full virtual machine interface to
3087 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3089 Just make sure your machine specific header file (for instance
3090 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3091 Information structure as we define in include/u-boot.h, and make
3092 sure that your definition of IMAP_ADDR uses the same value as your
3093 U-Boot configuration in CFG_IMMR.
3096 Configuring the Linux kernel:
3097 -----------------------------
3099 No specific requirements for U-Boot. Make sure you have some root
3100 device (initial ramdisk, NFS) for your target system.
3103 Building a Linux Image:
3104 -----------------------
3106 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3107 not used. If you use recent kernel source, a new build target
3108 "uImage" will exist which automatically builds an image usable by
3109 U-Boot. Most older kernels also have support for a "pImage" target,
3110 which was introduced for our predecessor project PPCBoot and uses a
3111 100% compatible format.
3120 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3121 encapsulate a compressed Linux kernel image with header information,
3122 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3124 * build a standard "vmlinux" kernel image (in ELF binary format):
3126 * convert the kernel into a raw binary image:
3128 ${CROSS_COMPILE}-objcopy -O binary \
3129 -R .note -R .comment \
3130 -S vmlinux linux.bin
3132 * compress the binary image:
3136 * package compressed binary image for U-Boot:
3138 mkimage -A ppc -O linux -T kernel -C gzip \
3139 -a 0 -e 0 -n "Linux Kernel Image" \
3140 -d linux.bin.gz uImage
3143 The "mkimage" tool can also be used to create ramdisk images for use
3144 with U-Boot, either separated from the Linux kernel image, or
3145 combined into one file. "mkimage" encapsulates the images with a 64
3146 byte header containing information about target architecture,
3147 operating system, image type, compression method, entry points, time
3148 stamp, CRC32 checksums, etc.
3150 "mkimage" can be called in two ways: to verify existing images and
3151 print the header information, or to build new images.
3153 In the first form (with "-l" option) mkimage lists the information
3154 contained in the header of an existing U-Boot image; this includes
3155 checksum verification:
3157 tools/mkimage -l image
3158 -l ==> list image header information
3160 The second form (with "-d" option) is used to build a U-Boot image
3161 from a "data file" which is used as image payload:
3163 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3164 -n name -d data_file image
3165 -A ==> set architecture to 'arch'
3166 -O ==> set operating system to 'os'
3167 -T ==> set image type to 'type'
3168 -C ==> set compression type 'comp'
3169 -a ==> set load address to 'addr' (hex)
3170 -e ==> set entry point to 'ep' (hex)
3171 -n ==> set image name to 'name'
3172 -d ==> use image data from 'datafile'
3174 Right now, all Linux kernels for PowerPC systems use the same load
3175 address (0x00000000), but the entry point address depends on the
3178 - 2.2.x kernels have the entry point at 0x0000000C,
3179 - 2.3.x and later kernels have the entry point at 0x00000000.
3181 So a typical call to build a U-Boot image would read:
3183 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3184 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3185 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3186 > examples/uImage.TQM850L
3187 Image Name: 2.4.4 kernel for TQM850L
3188 Created: Wed Jul 19 02:34:59 2000
3189 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3190 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3191 Load Address: 0x00000000
3192 Entry Point: 0x00000000
3194 To verify the contents of the image (or check for corruption):
3196 -> tools/mkimage -l examples/uImage.TQM850L
3197 Image Name: 2.4.4 kernel for TQM850L
3198 Created: Wed Jul 19 02:34:59 2000
3199 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3200 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3201 Load Address: 0x00000000
3202 Entry Point: 0x00000000
3204 NOTE: for embedded systems where boot time is critical you can trade
3205 speed for memory and install an UNCOMPRESSED image instead: this
3206 needs more space in Flash, but boots much faster since it does not
3207 need to be uncompressed:
3209 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3210 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3211 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3212 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3213 > examples/uImage.TQM850L-uncompressed
3214 Image Name: 2.4.4 kernel for TQM850L
3215 Created: Wed Jul 19 02:34:59 2000
3216 Image Type: PowerPC Linux Kernel Image (uncompressed)
3217 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3218 Load Address: 0x00000000
3219 Entry Point: 0x00000000
3222 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3223 when your kernel is intended to use an initial ramdisk:
3225 -> tools/mkimage -n 'Simple Ramdisk Image' \
3226 > -A ppc -O linux -T ramdisk -C gzip \
3227 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3228 Image Name: Simple Ramdisk Image
3229 Created: Wed Jan 12 14:01:50 2000
3230 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3231 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3232 Load Address: 0x00000000
3233 Entry Point: 0x00000000
3236 Installing a Linux Image:
3237 -------------------------
3239 To downloading a U-Boot image over the serial (console) interface,
3240 you must convert the image to S-Record format:
3242 objcopy -I binary -O srec examples/image examples/image.srec
3244 The 'objcopy' does not understand the information in the U-Boot
3245 image header, so the resulting S-Record file will be relative to
3246 address 0x00000000. To load it to a given address, you need to
3247 specify the target address as 'offset' parameter with the 'loads'
3250 Example: install the image to address 0x40100000 (which on the
3251 TQM8xxL is in the first Flash bank):
3253 => erase 40100000 401FFFFF
3259 ## Ready for S-Record download ...
3260 ~>examples/image.srec
3261 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3263 15989 15990 15991 15992
3264 [file transfer complete]
3266 ## Start Addr = 0x00000000
3269 You can check the success of the download using the 'iminfo' command;
3270 this includes a checksum verification so you can be sure no data
3271 corruption happened:
3275 ## Checking Image at 40100000 ...
3276 Image Name: 2.2.13 for initrd on TQM850L
3277 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3278 Data Size: 335725 Bytes = 327 kB = 0 MB
3279 Load Address: 00000000
3280 Entry Point: 0000000c
3281 Verifying Checksum ... OK
3287 The "bootm" command is used to boot an application that is stored in
3288 memory (RAM or Flash). In case of a Linux kernel image, the contents
3289 of the "bootargs" environment variable is passed to the kernel as
3290 parameters. You can check and modify this variable using the
3291 "printenv" and "setenv" commands:
3294 => printenv bootargs
3295 bootargs=root=/dev/ram
3297 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3299 => printenv bootargs
3300 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3303 ## Booting Linux kernel at 40020000 ...
3304 Image Name: 2.2.13 for NFS on TQM850L
3305 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3306 Data Size: 381681 Bytes = 372 kB = 0 MB
3307 Load Address: 00000000
3308 Entry Point: 0000000c
3309 Verifying Checksum ... OK
3310 Uncompressing Kernel Image ... OK
3311 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
3312 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3313 time_init: decrementer frequency = 187500000/60
3314 Calibrating delay loop... 49.77 BogoMIPS
3315 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3318 If you want to boot a Linux kernel with initial ram disk, you pass
3319 the memory addresses of both the kernel and the initrd image (PPBCOOT
3320 format!) to the "bootm" command:
3322 => imi 40100000 40200000
3324 ## Checking Image at 40100000 ...
3325 Image Name: 2.2.13 for initrd on TQM850L
3326 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3327 Data Size: 335725 Bytes = 327 kB = 0 MB
3328 Load Address: 00000000
3329 Entry Point: 0000000c
3330 Verifying Checksum ... OK
3332 ## Checking Image at 40200000 ...
3333 Image Name: Simple Ramdisk Image
3334 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3335 Data Size: 566530 Bytes = 553 kB = 0 MB
3336 Load Address: 00000000
3337 Entry Point: 00000000
3338 Verifying Checksum ... OK
3340 => bootm 40100000 40200000
3341 ## Booting Linux kernel at 40100000 ...
3342 Image Name: 2.2.13 for initrd on TQM850L
3343 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3344 Data Size: 335725 Bytes = 327 kB = 0 MB
3345 Load Address: 00000000
3346 Entry Point: 0000000c
3347 Verifying Checksum ... OK
3348 Uncompressing Kernel Image ... OK
3349 ## Loading RAMDisk Image at 40200000 ...
3350 Image Name: Simple Ramdisk Image
3351 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3352 Data Size: 566530 Bytes = 553 kB = 0 MB
3353 Load Address: 00000000
3354 Entry Point: 00000000
3355 Verifying Checksum ... OK
3356 Loading Ramdisk ... OK
3357 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
3358 Boot arguments: root=/dev/ram
3359 time_init: decrementer frequency = 187500000/60
3360 Calibrating delay loop... 49.77 BogoMIPS
3362 RAMDISK: Compressed image found at block 0
3363 VFS: Mounted root (ext2 filesystem).
3367 Boot Linux and pass a flat device tree:
3370 First, U-Boot must be compiled with the appropriate defines. See the section
3371 titled "Linux Kernel Interface" above for a more in depth explanation. The
3372 following is an example of how to start a kernel and pass an updated
3378 oft=oftrees/mpc8540ads.dtb
3379 => tftp $oftaddr $oft
3380 Speed: 1000, full duplex
3382 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3383 Filename 'oftrees/mpc8540ads.dtb'.
3384 Load address: 0x300000
3387 Bytes transferred = 4106 (100a hex)
3388 => tftp $loadaddr $bootfile
3389 Speed: 1000, full duplex
3391 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3393 Load address: 0x200000
3394 Loading:############
3396 Bytes transferred = 1029407 (fb51f hex)
3401 => bootm $loadaddr - $oftaddr
3402 ## Booting image at 00200000 ...
3403 Image Name: Linux-2.6.17-dirty
3404 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3405 Data Size: 1029343 Bytes = 1005.2 kB
3406 Load Address: 00000000
3407 Entry Point: 00000000
3408 Verifying Checksum ... OK
3409 Uncompressing Kernel Image ... OK
3410 Booting using flat device tree at 0x300000
3411 Using MPC85xx ADS machine description
3412 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3416 More About U-Boot Image Types:
3417 ------------------------------
3419 U-Boot supports the following image types:
3421 "Standalone Programs" are directly runnable in the environment
3422 provided by U-Boot; it is expected that (if they behave
3423 well) you can continue to work in U-Boot after return from
3424 the Standalone Program.
3425 "OS Kernel Images" are usually images of some Embedded OS which
3426 will take over control completely. Usually these programs
3427 will install their own set of exception handlers, device
3428 drivers, set up the MMU, etc. - this means, that you cannot
3429 expect to re-enter U-Boot except by resetting the CPU.
3430 "RAMDisk Images" are more or less just data blocks, and their
3431 parameters (address, size) are passed to an OS kernel that is
3433 "Multi-File Images" contain several images, typically an OS
3434 (Linux) kernel image and one or more data images like
3435 RAMDisks. This construct is useful for instance when you want
3436 to boot over the network using BOOTP etc., where the boot
3437 server provides just a single image file, but you want to get
3438 for instance an OS kernel and a RAMDisk image.
3440 "Multi-File Images" start with a list of image sizes, each
3441 image size (in bytes) specified by an "uint32_t" in network
3442 byte order. This list is terminated by an "(uint32_t)0".
3443 Immediately after the terminating 0 follow the images, one by
3444 one, all aligned on "uint32_t" boundaries (size rounded up to
3445 a multiple of 4 bytes).
3447 "Firmware Images" are binary images containing firmware (like
3448 U-Boot or FPGA images) which usually will be programmed to
3451 "Script files" are command sequences that will be executed by
3452 U-Boot's command interpreter; this feature is especially
3453 useful when you configure U-Boot to use a real shell (hush)
3454 as command interpreter.
3460 One of the features of U-Boot is that you can dynamically load and
3461 run "standalone" applications, which can use some resources of
3462 U-Boot like console I/O functions or interrupt services.
3464 Two simple examples are included with the sources:
3469 'examples/hello_world.c' contains a small "Hello World" Demo
3470 application; it is automatically compiled when you build U-Boot.
3471 It's configured to run at address 0x00040004, so you can play with it
3475 ## Ready for S-Record download ...
3476 ~>examples/hello_world.srec
3477 1 2 3 4 5 6 7 8 9 10 11 ...
3478 [file transfer complete]
3480 ## Start Addr = 0x00040004
3482 => go 40004 Hello World! This is a test.
3483 ## Starting application at 0x00040004 ...
3494 Hit any key to exit ...
3496 ## Application terminated, rc = 0x0
3498 Another example, which demonstrates how to register a CPM interrupt
3499 handler with the U-Boot code, can be found in 'examples/timer.c'.
3500 Here, a CPM timer is set up to generate an interrupt every second.
3501 The interrupt service routine is trivial, just printing a '.'
3502 character, but this is just a demo program. The application can be
3503 controlled by the following keys:
3505 ? - print current values og the CPM Timer registers
3506 b - enable interrupts and start timer
3507 e - stop timer and disable interrupts
3508 q - quit application
3511 ## Ready for S-Record download ...
3512 ~>examples/timer.srec
3513 1 2 3 4 5 6 7 8 9 10 11 ...
3514 [file transfer complete]
3516 ## Start Addr = 0x00040004
3519 ## Starting application at 0x00040004 ...
3522 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3525 [q, b, e, ?] Set interval 1000000 us
3528 [q, b, e, ?] ........
3529 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3532 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3535 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3538 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3540 [q, b, e, ?] ...Stopping timer
3542 [q, b, e, ?] ## Application terminated, rc = 0x0
3548 Over time, many people have reported problems when trying to use the
3549 "minicom" terminal emulation program for serial download. I (wd)
3550 consider minicom to be broken, and recommend not to use it. Under
3551 Unix, I recommend to use C-Kermit for general purpose use (and
3552 especially for kermit binary protocol download ("loadb" command), and
3553 use "cu" for S-Record download ("loads" command).
3555 Nevertheless, if you absolutely want to use it try adding this
3556 configuration to your "File transfer protocols" section:
3558 Name Program Name U/D FullScr IO-Red. Multi
3559 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3560 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3566 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3567 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3569 Building requires a cross environment; it is known to work on
3570 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3571 need gmake since the Makefiles are not compatible with BSD make).
3572 Note that the cross-powerpc package does not install include files;
3573 attempting to build U-Boot will fail because <machine/ansi.h> is
3574 missing. This file has to be installed and patched manually:
3576 # cd /usr/pkg/cross/powerpc-netbsd/include
3578 # ln -s powerpc machine
3579 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3580 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3582 Native builds *don't* work due to incompatibilities between native
3583 and U-Boot include files.
3585 Booting assumes that (the first part of) the image booted is a
3586 stage-2 loader which in turn loads and then invokes the kernel
3587 proper. Loader sources will eventually appear in the NetBSD source
3588 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3589 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3592 Implementation Internals:
3593 =========================
3595 The following is not intended to be a complete description of every
3596 implementation detail. However, it should help to understand the
3597 inner workings of U-Boot and make it easier to port it to custom
3601 Initial Stack, Global Data:
3602 ---------------------------
3604 The implementation of U-Boot is complicated by the fact that U-Boot
3605 starts running out of ROM (flash memory), usually without access to
3606 system RAM (because the memory controller is not initialized yet).
3607 This means that we don't have writable Data or BSS segments, and BSS
3608 is not initialized as zero. To be able to get a C environment working
3609 at all, we have to allocate at least a minimal stack. Implementation
3610 options for this are defined and restricted by the CPU used: Some CPU
3611 models provide on-chip memory (like the IMMR area on MPC8xx and
3612 MPC826x processors), on others (parts of) the data cache can be
3613 locked as (mis-) used as memory, etc.
3615 Chris Hallinan posted a good summary of these issues to the
3616 u-boot-users mailing list:
3618 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3619 From: "Chris Hallinan" <clh@net1plus.com>
3620 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3623 Correct me if I'm wrong, folks, but the way I understand it
3624 is this: Using DCACHE as initial RAM for Stack, etc, does not
3625 require any physical RAM backing up the cache. The cleverness
3626 is that the cache is being used as a temporary supply of
3627 necessary storage before the SDRAM controller is setup. It's
3628 beyond the scope of this list to expain the details, but you
3629 can see how this works by studying the cache architecture and
3630 operation in the architecture and processor-specific manuals.
3632 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3633 is another option for the system designer to use as an
3634 initial stack/ram area prior to SDRAM being available. Either
3635 option should work for you. Using CS 4 should be fine if your
3636 board designers haven't used it for something that would
3637 cause you grief during the initial boot! It is frequently not
3640 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3641 with your processor/board/system design. The default value
3642 you will find in any recent u-boot distribution in
3643 walnut.h should work for you. I'd set it to a value larger
3644 than your SDRAM module. If you have a 64MB SDRAM module, set
3645 it above 400_0000. Just make sure your board has no resources
3646 that are supposed to respond to that address! That code in
3647 start.S has been around a while and should work as is when
3648 you get the config right.
3653 It is essential to remember this, since it has some impact on the C
3654 code for the initialization procedures:
3656 * Initialized global data (data segment) is read-only. Do not attempt
3659 * Do not use any unitialized global data (or implicitely initialized
3660 as zero data - BSS segment) at all - this is undefined, initiali-
3661 zation is performed later (when relocating to RAM).
3663 * Stack space is very limited. Avoid big data buffers or things like
3666 Having only the stack as writable memory limits means we cannot use
3667 normal global data to share information beween the code. But it
3668 turned out that the implementation of U-Boot can be greatly
3669 simplified by making a global data structure (gd_t) available to all
3670 functions. We could pass a pointer to this data as argument to _all_
3671 functions, but this would bloat the code. Instead we use a feature of
3672 the GCC compiler (Global Register Variables) to share the data: we
3673 place a pointer (gd) to the global data into a register which we
3674 reserve for this purpose.
3676 When choosing a register for such a purpose we are restricted by the
3677 relevant (E)ABI specifications for the current architecture, and by
3678 GCC's implementation.
3680 For PowerPC, the following registers have specific use:
3682 R2: reserved for system use
3683 R3-R4: parameter passing and return values
3684 R5-R10: parameter passing
3685 R13: small data area pointer
3689 (U-Boot also uses R14 as internal GOT pointer.)
3691 ==> U-Boot will use R2 to hold a pointer to the global data
3693 Note: on PPC, we could use a static initializer (since the
3694 address of the global data structure is known at compile time),
3695 but it turned out that reserving a register results in somewhat
3696 smaller code - although the code savings are not that big (on
3697 average for all boards 752 bytes for the whole U-Boot image,
3698 624 text + 127 data).
3700 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3701 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3703 ==> U-Boot will use P5 to hold a pointer to the global data
3705 On ARM, the following registers are used:
3707 R0: function argument word/integer result
3708 R1-R3: function argument word
3710 R10: stack limit (used only if stack checking if enabled)
3711 R11: argument (frame) pointer
3712 R12: temporary workspace
3715 R15: program counter
3717 ==> U-Boot will use R8 to hold a pointer to the global data
3719 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3720 or current versions of GCC may "optimize" the code too much.
3725 U-Boot runs in system state and uses physical addresses, i.e. the
3726 MMU is not used either for address mapping nor for memory protection.
3728 The available memory is mapped to fixed addresses using the memory
3729 controller. In this process, a contiguous block is formed for each
3730 memory type (Flash, SDRAM, SRAM), even when it consists of several
3731 physical memory banks.
3733 U-Boot is installed in the first 128 kB of the first Flash bank (on
3734 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3735 booting and sizing and initializing DRAM, the code relocates itself
3736 to the upper end of DRAM. Immediately below the U-Boot code some
3737 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3738 configuration setting]. Below that, a structure with global Board
3739 Info data is placed, followed by the stack (growing downward).
3741 Additionally, some exception handler code is copied to the low 8 kB
3742 of DRAM (0x00000000 ... 0x00001FFF).
3744 So a typical memory configuration with 16 MB of DRAM could look like
3747 0x0000 0000 Exception Vector code
3750 0x0000 2000 Free for Application Use
3756 0x00FB FF20 Monitor Stack (Growing downward)
3757 0x00FB FFAC Board Info Data and permanent copy of global data
3758 0x00FC 0000 Malloc Arena
3761 0x00FE 0000 RAM Copy of Monitor Code
3762 ... eventually: LCD or video framebuffer
3763 ... eventually: pRAM (Protected RAM - unchanged by reset)
3764 0x00FF FFFF [End of RAM]
3767 System Initialization:
3768 ----------------------
3770 In the reset configuration, U-Boot starts at the reset entry point
3771 (on most PowerPC systens at address 0x00000100). Because of the reset
3772 configuration for CS0# this is a mirror of the onboard Flash memory.
3773 To be able to re-map memory U-Boot then jumps to its link address.
3774 To be able to implement the initialization code in C, a (small!)
3775 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3776 which provide such a feature like MPC8xx or MPC8260), or in a locked
3777 part of the data cache. After that, U-Boot initializes the CPU core,
3778 the caches and the SIU.
3780 Next, all (potentially) available memory banks are mapped using a
3781 preliminary mapping. For example, we put them on 512 MB boundaries
3782 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3783 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3784 programmed for SDRAM access. Using the temporary configuration, a
3785 simple memory test is run that determines the size of the SDRAM
3788 When there is more than one SDRAM bank, and the banks are of
3789 different size, the largest is mapped first. For equal size, the first
3790 bank (CS2#) is mapped first. The first mapping is always for address
3791 0x00000000, with any additional banks following immediately to create
3792 contiguous memory starting from 0.
3794 Then, the monitor installs itself at the upper end of the SDRAM area
3795 and allocates memory for use by malloc() and for the global Board
3796 Info data; also, the exception vector code is copied to the low RAM
3797 pages, and the final stack is set up.
3799 Only after this relocation will you have a "normal" C environment;
3800 until that you are restricted in several ways, mostly because you are
3801 running from ROM, and because the code will have to be relocated to a
3805 U-Boot Porting Guide:
3806 ----------------------
3808 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3812 int main (int argc, char *argv[])
3814 sighandler_t no_more_time;
3816 signal (SIGALRM, no_more_time);
3817 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3819 if (available_money > available_manpower) {
3820 pay consultant to port U-Boot;
3824 Download latest U-Boot source;
3826 Subscribe to u-boot-users mailing list;
3829 email ("Hi, I am new to U-Boot, how do I get started?");
3833 Read the README file in the top level directory;
3834 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3835 Read the source, Luke;
3838 if (available_money > toLocalCurrency ($2500)) {
3841 Add a lot of aggravation and time;
3844 Create your own board support subdirectory;
3846 Create your own board config file;
3850 Add / modify source code;
3854 email ("Hi, I am having problems...");
3856 Send patch file to Wolfgang;
3861 void no_more_time (int sig)
3870 All contributions to U-Boot should conform to the Linux kernel
3871 coding style; see the file "Documentation/CodingStyle" and the script
3872 "scripts/Lindent" in your Linux kernel source directory. In sources
3873 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3874 spaces before parameters to function calls) is actually used.
3876 Source files originating from a different project (for example the
3877 MTD subsystem) are generally exempt from these guidelines and are not
3878 reformated to ease subsequent migration to newer versions of those
3881 Please note that U-Boot is implemented in C (and to some small parts in
3882 Assembler); no C++ is used, so please do not use C++ style comments (//)
3885 Please also stick to the following formatting rules:
3886 - remove any trailing white space
3887 - use TAB characters for indentation, not spaces
3888 - make sure NOT to use DOS '\r\n' line feeds
3889 - do not add more than 2 empty lines to source files
3890 - do not add trailing empty lines to source files
3892 Submissions which do not conform to the standards may be returned
3893 with a request to reformat the changes.
3899 Since the number of patches for U-Boot is growing, we need to
3900 establish some rules. Submissions which do not conform to these rules
3901 may be rejected, even when they contain important and valuable stuff.
3903 Patches shall be sent to the u-boot-users mailing list.
3905 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3907 When you send a patch, please include the following information with
3910 * For bug fixes: a description of the bug and how your patch fixes
3911 this bug. Please try to include a way of demonstrating that the
3912 patch actually fixes something.
3914 * For new features: a description of the feature and your
3917 * A CHANGELOG entry as plaintext (separate from the patch)
3919 * For major contributions, your entry to the CREDITS file
3921 * When you add support for a new board, don't forget to add this
3922 board to the MAKEALL script, too.
3924 * If your patch adds new configuration options, don't forget to
3925 document these in the README file.
3927 * The patch itself. If you are using git (which is *strongly*
3928 recommended) you can easily generate the patch using the
3929 "git-format-patch". If you then use "git-send-email" to send it to
3930 the U-Boot mailing list, you will avoid most of the common problems
3931 with some other mail clients.
3933 If you cannot use git, use "diff -purN OLD NEW". If your version of
3934 diff does not support these options, then get the latest version of
3937 The current directory when running this command shall be the parent
3938 directory of the U-Boot source tree (i. e. please make sure that
3939 your patch includes sufficient directory information for the
3942 We prefer patches as plain text. MIME attachments are discouraged,
3943 and compressed attachments must not be used.
3945 * If one logical set of modifications affects or creates several
3946 files, all these changes shall be submitted in a SINGLE patch file.
3948 * Changesets that contain different, unrelated modifications shall be
3949 submitted as SEPARATE patches, one patch per changeset.
3954 * Before sending the patch, run the MAKEALL script on your patched
3955 source tree and make sure that no errors or warnings are reported
3956 for any of the boards.
3958 * Keep your modifications to the necessary minimum: A patch
3959 containing several unrelated changes or arbitrary reformats will be
3960 returned with a request to re-formatting / split it.
3962 * If you modify existing code, make sure that your new code does not
3963 add to the memory footprint of the code ;-) Small is beautiful!
3964 When adding new features, these should compile conditionally only
3965 (using #ifdef), and the resulting code with the new feature
3966 disabled must not need more memory than the old code without your
3969 * Remember that there is a size limit of 40 kB per message on the
3970 u-boot-users mailing list. Bigger patches will be moderated. If
3971 they are reasonable and not bigger than 100 kB, they will be
3972 acknowledged. Even bigger patches should be avoided.
projects / karo-tx-uboot.git / blob