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.
353 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
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
365 * Deprecated, see CONFIG_OF_LIBFDT
366 * Original ft_build.c-based support
367 * Automatically modifies the dft as part of the bootm command
368 * The environment variable "disable_of", when set,
369 disables this functionality.
371 OF_CPU - The proper name of the cpus node.
372 OF_SOC - The proper name of the soc node.
373 OF_TBCLK - The timebase frequency.
374 OF_STDOUT_PATH - The path to the console device
376 boards with QUICC Engines require OF_QE to set UCC mac addresses
378 CONFIG_OF_BOARD_SETUP
380 Board code has addition modification that it wants to make
381 to the flat device tree before handing it off to the kernel
385 This define fills in the correct boot cpu in the boot
386 param header, the default value is zero if undefined.
391 Define this if you want support for Amba PrimeCell PL010 UARTs.
395 Define this if you want support for Amba PrimeCell PL011 UARTs.
399 If you have Amba PrimeCell PL011 UARTs, set this variable to
400 the clock speed of the UARTs.
404 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
405 define this to a list of base addresses for each (supported)
406 port. See e.g. include/configs/versatile.h
410 Depending on board, define exactly one serial port
411 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
412 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
413 console by defining CONFIG_8xx_CONS_NONE
415 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
416 port routines must be defined elsewhere
417 (i.e. serial_init(), serial_getc(), ...)
420 Enables console device for a color framebuffer. Needs following
421 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
422 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
424 VIDEO_HW_RECTFILL graphic chip supports
427 VIDEO_HW_BITBLT graphic chip supports
428 bit-blit (cf. smiLynxEM)
429 VIDEO_VISIBLE_COLS visible pixel columns
431 VIDEO_VISIBLE_ROWS visible pixel rows
432 VIDEO_PIXEL_SIZE bytes per pixel
433 VIDEO_DATA_FORMAT graphic data format
434 (0-5, cf. cfb_console.c)
435 VIDEO_FB_ADRS framebuffer address
436 VIDEO_KBD_INIT_FCT keyboard int fct
437 (i.e. i8042_kbd_init())
438 VIDEO_TSTC_FCT test char fct
440 VIDEO_GETC_FCT get char fct
442 CONFIG_CONSOLE_CURSOR cursor drawing on/off
443 (requires blink timer
445 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
446 CONFIG_CONSOLE_TIME display time/date info in
448 (requires CONFIG_CMD_DATE)
449 CONFIG_VIDEO_LOGO display Linux logo in
451 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
452 linux_logo.h for logo.
453 Requires CONFIG_VIDEO_LOGO
454 CONFIG_CONSOLE_EXTRA_INFO
455 addional board info beside
458 When CONFIG_CFB_CONSOLE is defined, video console is
459 default i/o. Serial console can be forced with
460 environment 'console=serial'.
462 When CONFIG_SILENT_CONSOLE is defined, all console
463 messages (by U-Boot and Linux!) can be silenced with
464 the "silent" environment variable. See
465 doc/README.silent for more information.
468 CONFIG_BAUDRATE - in bps
469 Select one of the baudrates listed in
470 CFG_BAUDRATE_TABLE, see below.
471 CFG_BRGCLK_PRESCALE, baudrate prescale
473 - Interrupt driven serial port input:
474 CONFIG_SERIAL_SOFTWARE_FIFO
477 Use an interrupt handler for receiving data on the
478 serial port. It also enables using hardware handshake
479 (RTS/CTS) and UART's built-in FIFO. Set the number of
480 bytes the interrupt driven input buffer should have.
482 Leave undefined to disable this feature, including
483 disable the buffer and hardware handshake.
485 - Console UART Number:
489 If defined internal UART1 (and not UART0) is used
490 as default U-Boot console.
492 - Boot Delay: CONFIG_BOOTDELAY - in seconds
493 Delay before automatically booting the default image;
494 set to -1 to disable autoboot.
496 See doc/README.autoboot for these options that
497 work with CONFIG_BOOTDELAY. None are required.
498 CONFIG_BOOT_RETRY_TIME
499 CONFIG_BOOT_RETRY_MIN
500 CONFIG_AUTOBOOT_KEYED
501 CONFIG_AUTOBOOT_PROMPT
502 CONFIG_AUTOBOOT_DELAY_STR
503 CONFIG_AUTOBOOT_STOP_STR
504 CONFIG_AUTOBOOT_DELAY_STR2
505 CONFIG_AUTOBOOT_STOP_STR2
506 CONFIG_ZERO_BOOTDELAY_CHECK
507 CONFIG_RESET_TO_RETRY
511 Only needed when CONFIG_BOOTDELAY is enabled;
512 define a command string that is automatically executed
513 when no character is read on the console interface
514 within "Boot Delay" after reset.
517 This can be used to pass arguments to the bootm
518 command. The value of CONFIG_BOOTARGS goes into the
519 environment value "bootargs".
521 CONFIG_RAMBOOT and CONFIG_NFSBOOT
522 The value of these goes into the environment as
523 "ramboot" and "nfsboot" respectively, and can be used
524 as a convenience, when switching between booting from
530 When this option is #defined, the existence of the
531 environment variable "preboot" will be checked
532 immediately before starting the CONFIG_BOOTDELAY
533 countdown and/or running the auto-boot command resp.
534 entering interactive mode.
536 This feature is especially useful when "preboot" is
537 automatically generated or modified. For an example
538 see the LWMON board specific code: here "preboot" is
539 modified when the user holds down a certain
540 combination of keys on the (special) keyboard when
543 - Serial Download Echo Mode:
545 If defined to 1, all characters received during a
546 serial download (using the "loads" command) are
547 echoed back. This might be needed by some terminal
548 emulations (like "cu"), but may as well just take
549 time on others. This setting #define's the initial
550 value of the "loads_echo" environment variable.
552 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
554 Select one of the baudrates listed in
555 CFG_BAUDRATE_TABLE, see below.
558 Monitor commands can be included or excluded
559 from the build by using the #include files
560 "config_cmd_all.h" and #undef'ing unwanted
561 commands, or using "config_cmd_default.h"
562 and augmenting with additional #define's
565 The default command configuration includes all commands
566 except those marked below with a "*".
568 CONFIG_CMD_ASKENV * ask for env variable
569 CONFIG_CMD_AUTOSCRIPT Autoscript Support
570 CONFIG_CMD_BDI bdinfo
571 CONFIG_CMD_BEDBUG * Include BedBug Debugger
572 CONFIG_CMD_BMP * BMP support
573 CONFIG_CMD_BSP * Board specific commands
574 CONFIG_CMD_BOOTD bootd
575 CONFIG_CMD_CACHE * icache, dcache
576 CONFIG_CMD_CONSOLE coninfo
577 CONFIG_CMD_DATE * support for RTC, date/time...
578 CONFIG_CMD_DHCP * DHCP support
579 CONFIG_CMD_DIAG * Diagnostics
580 CONFIG_CMD_DOC * Disk-On-Chip Support
581 CONFIG_CMD_DTT * Digital Therm and Thermostat
582 CONFIG_CMD_ECHO echo arguments
583 CONFIG_CMD_EEPROM * EEPROM read/write support
584 CONFIG_CMD_ELF * bootelf, bootvx
585 CONFIG_CMD_ENV saveenv
586 CONFIG_CMD_FDC * Floppy Disk Support
587 CONFIG_CMD_FAT * FAT partition support
588 CONFIG_CMD_FDOS * Dos diskette Support
589 CONFIG_CMD_FLASH flinfo, erase, protect
590 CONFIG_CMD_FPGA FPGA device initialization support
591 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
592 CONFIG_CMD_I2C * I2C serial bus support
593 CONFIG_CMD_IDE * IDE harddisk support
594 CONFIG_CMD_IMI iminfo
595 CONFIG_CMD_IMLS List all found images
596 CONFIG_CMD_IMMAP * IMMR dump support
597 CONFIG_CMD_IRQ * irqinfo
598 CONFIG_CMD_ITEST Integer/string test of 2 values
599 CONFIG_CMD_JFFS2 * JFFS2 Support
600 CONFIG_CMD_KGDB * kgdb
601 CONFIG_CMD_LOADB loadb
602 CONFIG_CMD_LOADS loads
603 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
605 CONFIG_CMD_MISC Misc functions like sleep etc
606 CONFIG_CMD_MMC * MMC memory mapped support
607 CONFIG_CMD_MII * MII utility commands
608 CONFIG_CMD_NAND * NAND support
609 CONFIG_CMD_NET bootp, tftpboot, rarpboot
610 CONFIG_CMD_PCI * pciinfo
611 CONFIG_CMD_PCMCIA * PCMCIA support
612 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
614 CONFIG_CMD_PORTIO * Port I/O
615 CONFIG_CMD_REGINFO * Register dump
616 CONFIG_CMD_RUN run command in env variable
617 CONFIG_CMD_SAVES * save S record dump
618 CONFIG_CMD_SCSI * SCSI Support
619 CONFIG_CMD_SDRAM * print SDRAM configuration information
620 (requires CONFIG_CMD_I2C)
621 CONFIG_CMD_SETGETDCR Support for DCR Register access
623 CONFIG_CMD_SPI * SPI serial bus support
624 CONFIG_CMD_USB * USB support
625 CONFIG_CMD_VFD * VFD support (TRAB)
626 CONFIG_CMD_CDP * Cisco Discover Protocol support
627 CONFIG_CMD_FSL * Microblaze FSL support
630 EXAMPLE: If you want all functions except of network
631 support you can write:
633 #include "config_cmd_all.h"
634 #undef CONFIG_CMD_NET
637 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
639 Note: Don't enable the "icache" and "dcache" commands
640 (configuration option CONFIG_CMD_CACHE) unless you know
641 what you (and your U-Boot users) are doing. Data
642 cache cannot be enabled on systems like the 8xx or
643 8260 (where accesses to the IMMR region must be
644 uncached), and it cannot be disabled on all other
645 systems where we (mis-) use the data cache to hold an
646 initial stack and some data.
649 XXX - this list needs to get updated!
653 If this variable is defined, it enables watchdog
654 support. There must be support in the platform specific
655 code for a watchdog. For the 8xx and 8260 CPUs, the
656 SIU Watchdog feature is enabled in the SYPCR
660 CONFIG_VERSION_VARIABLE
661 If this variable is defined, an environment variable
662 named "ver" is created by U-Boot showing the U-Boot
663 version as printed by the "version" command.
664 This variable is readonly.
668 When CONFIG_CMD_DATE is selected, the type of the RTC
669 has to be selected, too. Define exactly one of the
672 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
673 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
674 CONFIG_RTC_MC13783 - use MC13783 RTC
675 CONFIG_RTC_MC146818 - use MC146818 RTC
676 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
677 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
678 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
679 CONFIG_RTC_DS164x - use Dallas DS164x RTC
680 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
681 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
682 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
684 Note that if the RTC uses I2C, then the I2C interface
685 must also be configured. See I2C Support, below.
689 When CONFIG_TIMESTAMP is selected, the timestamp
690 (date and time) of an image is printed by image
691 commands like bootm or iminfo. This option is
692 automatically enabled when you select CONFIG_CMD_DATE .
695 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
696 and/or CONFIG_ISO_PARTITION
698 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
699 CONFIG_CMD_SCSI) you must configure support for at
700 least one partition type as well.
703 CONFIG_IDE_RESET_ROUTINE - this is defined in several
704 board configurations files but used nowhere!
706 CONFIG_IDE_RESET - is this is defined, IDE Reset will
707 be performed by calling the function
708 ide_set_reset(int reset)
709 which has to be defined in a board specific file
714 Set this to enable ATAPI support.
719 Set this to enable support for disks larger than 137GB
720 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
721 Whithout these , LBA48 support uses 32bit variables and will 'only'
722 support disks up to 2.1TB.
725 When enabled, makes the IDE subsystem use 64bit sector addresses.
729 At the moment only there is only support for the
730 SYM53C8XX SCSI controller; define
731 CONFIG_SCSI_SYM53C8XX to enable it.
733 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
734 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
735 CFG_SCSI_MAX_LUN] can be adjusted to define the
736 maximum numbers of LUNs, SCSI ID's and target
738 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
740 - NETWORK Support (PCI):
742 Support for Intel 8254x gigabit chips.
744 CONFIG_E1000_FALLBACK_MAC
745 default MAC for empty eeprom after production.
748 Support for Intel 82557/82559/82559ER chips.
749 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
750 write routine for first time initialisation.
753 Support for Digital 2114x chips.
754 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
755 modem chip initialisation (KS8761/QS6611).
758 Support for National dp83815 chips.
761 Support for National dp8382[01] gigabit chips.
763 - NETWORK Support (other):
765 CONFIG_DRIVER_LAN91C96
766 Support for SMSC's LAN91C96 chips.
769 Define this to hold the physical address
770 of the LAN91C96's I/O space
772 CONFIG_LAN91C96_USE_32_BIT
773 Define this to enable 32 bit addressing
775 CONFIG_DRIVER_SMC91111
776 Support for SMSC's LAN91C111 chip
779 Define this to hold the physical address
780 of the device (I/O space)
782 CONFIG_SMC_USE_32_BIT
783 Define this if data bus is 32 bits
785 CONFIG_SMC_USE_IOFUNCS
786 Define this to use i/o functions instead of macros
787 (some hardware wont work with macros)
789 CONFIG_DRIVER_SMC911X
790 Support for SMSC's LAN911x and LAN921x chips
792 CONFIG_DRIVER_SMC911X_BASE
793 Define this to hold the physical address
794 of the device (I/O space)
796 CONFIG_DRIVER_SMC911X_32_BIT
797 Define this if data bus is 32 bits
799 CONFIG_DRIVER_SMC911X_16_BIT
800 Define this if data bus is 16 bits. If your processor
801 automatically converts one 32 bit word to two 16 bit
802 words you may also try CONFIG_DRIVER_SMC911X_32_BIT.
805 At the moment only the UHCI host controller is
806 supported (PIP405, MIP405, MPC5200); define
807 CONFIG_USB_UHCI to enable it.
808 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
809 and define CONFIG_USB_STORAGE to enable the USB
812 Supported are USB Keyboards and USB Floppy drives
814 MPC5200 USB requires additional defines:
816 for 528 MHz Clock: 0x0001bbbb
818 for differential drivers: 0x00001000
819 for single ended drivers: 0x00005000
821 May be defined to allow interrupt polling
822 instead of using asynchronous interrupts
825 Define the below if you wish to use the USB console.
826 Once firmware is rebuilt from a serial console issue the
827 command "setenv stdin usbtty; setenv stdout usbtty" and
828 attach your usb cable. The Unix command "dmesg" should print
829 it has found a new device. The environment variable usbtty
830 can be set to gserial or cdc_acm to enable your device to
831 appear to a USB host as a Linux gserial device or a
832 Common Device Class Abstract Control Model serial device.
833 If you select usbtty = gserial you should be able to enumerate
835 # modprobe usbserial vendor=0xVendorID product=0xProductID
836 else if using cdc_acm, simply setting the environment
837 variable usbtty to be cdc_acm should suffice. The following
838 might be defined in YourBoardName.h
841 Define this to build a UDC device
844 Define this to have a tty type of device available to
845 talk to the UDC device
847 CFG_CONSOLE_IS_IN_ENV
848 Define this if you want stdin, stdout &/or stderr to
852 CFG_USB_EXTC_CLK 0xBLAH
853 Derive USB clock from external clock "blah"
854 - CFG_USB_EXTC_CLK 0x02
856 CFG_USB_BRG_CLK 0xBLAH
857 Derive USB clock from brgclk
858 - CFG_USB_BRG_CLK 0x04
860 If you have a USB-IF assigned VendorID then you may wish to
861 define your own vendor specific values either in BoardName.h
862 or directly in usbd_vendor_info.h. If you don't define
863 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
864 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
865 should pretend to be a Linux device to it's target host.
867 CONFIG_USBD_MANUFACTURER
868 Define this string as the name of your company for
869 - CONFIG_USBD_MANUFACTURER "my company"
871 CONFIG_USBD_PRODUCT_NAME
872 Define this string as the name of your product
873 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
876 Define this as your assigned Vendor ID from the USB
877 Implementors Forum. This *must* be a genuine Vendor ID
878 to avoid polluting the USB namespace.
879 - CONFIG_USBD_VENDORID 0xFFFF
881 CONFIG_USBD_PRODUCTID
882 Define this as the unique Product ID
884 - CONFIG_USBD_PRODUCTID 0xFFFF
888 The MMC controller on the Intel PXA is supported. To
889 enable this define CONFIG_MMC. The MMC can be
890 accessed from the boot prompt by mapping the device
891 to physical memory similar to flash. Command line is
892 enabled with CONFIG_CMD_MMC. The MMC driver also works with
893 the FAT fs. This is enabled with CONFIG_CMD_FAT.
895 - Journaling Flash filesystem support:
896 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
897 CONFIG_JFFS2_NAND_DEV
898 Define these for a default partition on a NAND device
900 CFG_JFFS2_FIRST_SECTOR,
901 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
902 Define these for a default partition on a NOR device
905 Define this to create an own partition. You have to provide a
906 function struct part_info* jffs2_part_info(int part_num)
908 If you define only one JFFS2 partition you may also want to
909 #define CFG_JFFS_SINGLE_PART 1
910 to disable the command chpart. This is the default when you
911 have not defined a custom partition
916 Define this to enable standard (PC-Style) keyboard
920 Standard PC keyboard driver with US (is default) and
921 GERMAN key layout (switch via environment 'keymap=de') support.
922 Export function i8042_kbd_init, i8042_tstc and i8042_getc
923 for cfb_console. Supports cursor blinking.
928 Define this to enable video support (for output to
933 Enable Chips & Technologies 69000 Video chip
935 CONFIG_VIDEO_SMI_LYNXEM
936 Enable Silicon Motion SMI 712/710/810 Video chip. The
937 video output is selected via environment 'videoout'
938 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
941 For the CT69000 and SMI_LYNXEM drivers, videomode is
942 selected via environment 'videomode'. Two diferent ways
944 - "videomode=num" 'num' is a standard LiLo mode numbers.
945 Following standard modes are supported (* is default):
947 Colors 640x480 800x600 1024x768 1152x864 1280x1024
948 -------------+---------------------------------------------
949 8 bits | 0x301* 0x303 0x305 0x161 0x307
950 15 bits | 0x310 0x313 0x316 0x162 0x319
951 16 bits | 0x311 0x314 0x317 0x163 0x31A
952 24 bits | 0x312 0x315 0x318 ? 0x31B
953 -------------+---------------------------------------------
954 (i.e. setenv videomode 317; saveenv; reset;)
956 - "videomode=bootargs" all the video parameters are parsed
957 from the bootargs. (See drivers/video/videomodes.c)
960 CONFIG_VIDEO_SED13806
961 Enable Epson SED13806 driver. This driver supports 8bpp
962 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
963 or CONFIG_VIDEO_SED13806_16BPP
968 Define this to enable a custom keyboard support.
969 This simply calls drv_keyboard_init() which must be
970 defined in your board-specific files.
971 The only board using this so far is RBC823.
973 - LCD Support: CONFIG_LCD
975 Define this to enable LCD support (for output to LCD
976 display); also select one of the supported displays
977 by defining one of these:
979 CONFIG_NEC_NL6448AC33:
981 NEC NL6448AC33-18. Active, color, single scan.
983 CONFIG_NEC_NL6448BC20
985 NEC NL6448BC20-08. 6.5", 640x480.
986 Active, color, single scan.
988 CONFIG_NEC_NL6448BC33_54
990 NEC NL6448BC33-54. 10.4", 640x480.
991 Active, color, single scan.
995 Sharp 320x240. Active, color, single scan.
996 It isn't 16x9, and I am not sure what it is.
998 CONFIG_SHARP_LQ64D341
1000 Sharp LQ64D341 display, 640x480.
1001 Active, color, single scan.
1005 HLD1045 display, 640x480.
1006 Active, color, single scan.
1010 Optrex CBL50840-2 NF-FW 99 22 M5
1012 Hitachi LMG6912RPFC-00T
1016 320x240. Black & white.
1018 Normally display is black on white background; define
1019 CFG_WHITE_ON_BLACK to get it inverted.
1021 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1023 If this option is set, the environment is checked for
1024 a variable "splashimage". If found, the usual display
1025 of logo, copyright and system information on the LCD
1026 is suppressed and the BMP image at the address
1027 specified in "splashimage" is loaded instead. The
1028 console is redirected to the "nulldev", too. This
1029 allows for a "silent" boot where a splash screen is
1030 loaded very quickly after power-on.
1032 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1034 If this option is set, additionally to standard BMP
1035 images, gzipped BMP images can be displayed via the
1036 splashscreen support or the bmp command.
1038 - Compression support:
1041 If this option is set, support for bzip2 compressed
1042 images is included. If not, only uncompressed and gzip
1043 compressed images are supported.
1045 NOTE: the bzip2 algorithm requires a lot of RAM, so
1046 the malloc area (as defined by CFG_MALLOC_LEN) should
1052 The address of PHY on MII bus.
1054 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1056 The clock frequency of the MII bus
1060 If this option is set, support for speed/duplex
1061 detection of Gigabit PHY is included.
1063 CONFIG_PHY_RESET_DELAY
1065 Some PHY like Intel LXT971A need extra delay after
1066 reset before any MII register access is possible.
1067 For such PHY, set this option to the usec delay
1068 required. (minimum 300usec for LXT971A)
1070 CONFIG_PHY_CMD_DELAY (ppc4xx)
1072 Some PHY like Intel LXT971A need extra delay after
1073 command issued before MII status register can be read
1080 Define a default value for ethernet address to use
1081 for the respective ethernet interface, in case this
1082 is not determined automatically.
1087 Define a default value for the IP address to use for
1088 the default ethernet interface, in case this is not
1089 determined through e.g. bootp.
1091 - Server IP address:
1094 Defines a default value for theIP address of a TFTP
1095 server to contact when using the "tftboot" command.
1097 - Multicast TFTP Mode:
1100 Defines whether you want to support multicast TFTP as per
1101 rfc-2090; for example to work with atftp. Lets lots of targets
1102 tftp down the same boot image concurrently. Note: the ethernet
1103 driver in use must provide a function: mcast() to join/leave a
1106 CONFIG_BOOTP_RANDOM_DELAY
1107 - BOOTP Recovery Mode:
1108 CONFIG_BOOTP_RANDOM_DELAY
1110 If you have many targets in a network that try to
1111 boot using BOOTP, you may want to avoid that all
1112 systems send out BOOTP requests at precisely the same
1113 moment (which would happen for instance at recovery
1114 from a power failure, when all systems will try to
1115 boot, thus flooding the BOOTP server. Defining
1116 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1117 inserted before sending out BOOTP requests. The
1118 following delays are inserted then:
1120 1st BOOTP request: delay 0 ... 1 sec
1121 2nd BOOTP request: delay 0 ... 2 sec
1122 3rd BOOTP request: delay 0 ... 4 sec
1124 BOOTP requests: delay 0 ... 8 sec
1126 - DHCP Advanced Options:
1127 You can fine tune the DHCP functionality by defining
1128 CONFIG_BOOTP_* symbols:
1130 CONFIG_BOOTP_SUBNETMASK
1131 CONFIG_BOOTP_GATEWAY
1132 CONFIG_BOOTP_HOSTNAME
1133 CONFIG_BOOTP_NISDOMAIN
1134 CONFIG_BOOTP_BOOTPATH
1135 CONFIG_BOOTP_BOOTFILESIZE
1138 CONFIG_BOOTP_SEND_HOSTNAME
1139 CONFIG_BOOTP_NTPSERVER
1140 CONFIG_BOOTP_TIMEOFFSET
1141 CONFIG_BOOTP_VENDOREX
1143 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1144 environment variable, not the BOOTP server.
1146 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1147 serverip from a DHCP server, it is possible that more
1148 than one DNS serverip is offered to the client.
1149 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1150 serverip will be stored in the additional environment
1151 variable "dnsip2". The first DNS serverip is always
1152 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1155 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1156 to do a dynamic update of a DNS server. To do this, they
1157 need the hostname of the DHCP requester.
1158 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1159 of the "hostname" environment variable is passed as
1160 option 12 to the DHCP server.
1162 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1164 A 32bit value in microseconds for a delay between
1165 receiving a "DHCP Offer" and sending the "DHCP Request".
1166 This fixes a problem with certain DHCP servers that don't
1167 respond 100% of the time to a "DHCP request". E.g. On an
1168 AT91RM9200 processor running at 180MHz, this delay needed
1169 to be *at least* 15,000 usec before a Windows Server 2003
1170 DHCP server would reply 100% of the time. I recommend at
1171 least 50,000 usec to be safe. The alternative is to hope
1172 that one of the retries will be successful but note that
1173 the DHCP timeout and retry process takes a longer than
1177 CONFIG_CDP_DEVICE_ID
1179 The device id used in CDP trigger frames.
1181 CONFIG_CDP_DEVICE_ID_PREFIX
1183 A two character string which is prefixed to the MAC address
1188 A printf format string which contains the ascii name of
1189 the port. Normally is set to "eth%d" which sets
1190 eth0 for the first ethernet, eth1 for the second etc.
1192 CONFIG_CDP_CAPABILITIES
1194 A 32bit integer which indicates the device capabilities;
1195 0x00000010 for a normal host which does not forwards.
1199 An ascii string containing the version of the software.
1203 An ascii string containing the name of the platform.
1207 A 32bit integer sent on the trigger.
1209 CONFIG_CDP_POWER_CONSUMPTION
1211 A 16bit integer containing the power consumption of the
1212 device in .1 of milliwatts.
1214 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1216 A byte containing the id of the VLAN.
1218 - Status LED: CONFIG_STATUS_LED
1220 Several configurations allow to display the current
1221 status using a LED. For instance, the LED will blink
1222 fast while running U-Boot code, stop blinking as
1223 soon as a reply to a BOOTP request was received, and
1224 start blinking slow once the Linux kernel is running
1225 (supported by a status LED driver in the Linux
1226 kernel). Defining CONFIG_STATUS_LED enables this
1229 - CAN Support: CONFIG_CAN_DRIVER
1231 Defining CONFIG_CAN_DRIVER enables CAN driver support
1232 on those systems that support this (optional)
1233 feature, like the TQM8xxL modules.
1235 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1237 These enable I2C serial bus commands. Defining either of
1238 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1239 include the appropriate I2C driver for the selected cpu.
1241 This will allow you to use i2c commands at the u-boot
1242 command line (as long as you set CONFIG_CMD_I2C in
1243 CONFIG_COMMANDS) and communicate with i2c based realtime
1244 clock chips. See common/cmd_i2c.c for a description of the
1245 command line interface.
1247 CONFIG_I2C_CMD_TREE is a recommended option that places
1248 all I2C commands under a single 'i2c' root command. The
1249 older 'imm', 'imd', 'iprobe' etc. commands are considered
1250 deprecated and may disappear in the future.
1252 CONFIG_HARD_I2C selects a hardware I2C controller.
1254 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1255 bit-banging) driver instead of CPM or similar hardware
1258 There are several other quantities that must also be
1259 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1261 In both cases you will need to define CFG_I2C_SPEED
1262 to be the frequency (in Hz) at which you wish your i2c bus
1263 to run and CFG_I2C_SLAVE to be the address of this node (ie
1264 the cpu's i2c node address).
1266 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1267 sets the cpu up as a master node and so its address should
1268 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1269 p.16-473). So, set CFG_I2C_SLAVE to 0.
1271 That's all that's required for CONFIG_HARD_I2C.
1273 If you use the software i2c interface (CONFIG_SOFT_I2C)
1274 then the following macros need to be defined (examples are
1275 from include/configs/lwmon.h):
1279 (Optional). Any commands necessary to enable the I2C
1280 controller or configure ports.
1282 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1286 (Only for MPC8260 CPU). The I/O port to use (the code
1287 assumes both bits are on the same port). Valid values
1288 are 0..3 for ports A..D.
1292 The code necessary to make the I2C data line active
1293 (driven). If the data line is open collector, this
1296 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1300 The code necessary to make the I2C data line tri-stated
1301 (inactive). If the data line is open collector, this
1304 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1308 Code that returns TRUE if the I2C data line is high,
1311 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1315 If <bit> is TRUE, sets the I2C data line high. If it
1316 is FALSE, it clears it (low).
1318 eg: #define I2C_SDA(bit) \
1319 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1320 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1324 If <bit> is TRUE, sets the I2C clock line high. If it
1325 is FALSE, it clears it (low).
1327 eg: #define I2C_SCL(bit) \
1328 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1329 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1333 This delay is invoked four times per clock cycle so this
1334 controls the rate of data transfer. The data rate thus
1335 is 1 / (I2C_DELAY * 4). Often defined to be something
1338 #define I2C_DELAY udelay(2)
1342 When a board is reset during an i2c bus transfer
1343 chips might think that the current transfer is still
1344 in progress. On some boards it is possible to access
1345 the i2c SCLK line directly, either by using the
1346 processor pin as a GPIO or by having a second pin
1347 connected to the bus. If this option is defined a
1348 custom i2c_init_board() routine in boards/xxx/board.c
1349 is run early in the boot sequence.
1351 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1353 This option enables configuration of bi_iic_fast[] flags
1354 in u-boot bd_info structure based on u-boot environment
1355 variable "i2cfast". (see also i2cfast)
1357 CONFIG_I2C_MULTI_BUS
1359 This option allows the use of multiple I2C buses, each of which
1360 must have a controller. At any point in time, only one bus is
1361 active. To switch to a different bus, use the 'i2c dev' command.
1362 Note that bus numbering is zero-based.
1366 This option specifies a list of I2C devices that will be skipped
1367 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1368 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1369 pairs. Otherwise, specify a 1D array of device addresses
1372 #undef CONFIG_I2C_MULTI_BUS
1373 #define CFG_I2C_NOPROBES {0x50,0x68}
1375 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1377 #define CONFIG_I2C_MULTI_BUS
1378 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1380 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1384 If defined, then this indicates the I2C bus number for DDR SPD.
1385 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1389 If defined, then this indicates the I2C bus number for the RTC.
1390 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1394 If defined, then this indicates the I2C bus number for the DTT.
1395 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1399 Define this option if you want to use Freescale's I2C driver in
1400 drivers/i2c/fsl_i2c.c.
1403 - SPI Support: CONFIG_SPI
1405 Enables SPI driver (so far only tested with
1406 SPI EEPROM, also an instance works with Crystal A/D and
1407 D/As on the SACSng board)
1411 Enables extended (16-bit) SPI EEPROM addressing.
1412 (symmetrical to CONFIG_I2C_X)
1416 Enables a software (bit-bang) SPI driver rather than
1417 using hardware support. This is a general purpose
1418 driver that only requires three general I/O port pins
1419 (two outputs, one input) to function. If this is
1420 defined, the board configuration must define several
1421 SPI configuration items (port pins to use, etc). For
1422 an example, see include/configs/sacsng.h.
1426 Enables a hardware SPI driver for general-purpose reads
1427 and writes. As with CONFIG_SOFT_SPI, the board configuration
1428 must define a list of chip-select function pointers.
1429 Currently supported on some MPC8xxx processors. For an
1430 example, see include/configs/mpc8349emds.h.
1434 Enables the driver for the SPI controllers on i.MX and MXC
1435 SoCs. Currently only i.MX31 is supported.
1437 - FPGA Support: CONFIG_FPGA
1439 Enables FPGA subsystem.
1441 CONFIG_FPGA_<vendor>
1443 Enables support for specific chip vendors.
1446 CONFIG_FPGA_<family>
1448 Enables support for FPGA family.
1449 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1453 Specify the number of FPGA devices to support.
1455 CFG_FPGA_PROG_FEEDBACK
1457 Enable printing of hash marks during FPGA configuration.
1461 Enable checks on FPGA configuration interface busy
1462 status by the configuration function. This option
1463 will require a board or device specific function to
1468 If defined, a function that provides delays in the FPGA
1469 configuration driver.
1471 CFG_FPGA_CHECK_CTRLC
1472 Allow Control-C to interrupt FPGA configuration
1474 CFG_FPGA_CHECK_ERROR
1476 Check for configuration errors during FPGA bitfile
1477 loading. For example, abort during Virtex II
1478 configuration if the INIT_B line goes low (which
1479 indicated a CRC error).
1483 Maximum time to wait for the INIT_B line to deassert
1484 after PROB_B has been deasserted during a Virtex II
1485 FPGA configuration sequence. The default time is 500
1490 Maximum time to wait for BUSY to deassert during
1491 Virtex II FPGA configuration. The default is 5 mS.
1493 CFG_FPGA_WAIT_CONFIG
1495 Time to wait after FPGA configuration. The default is
1498 - Configuration Management:
1501 If defined, this string will be added to the U-Boot
1502 version information (U_BOOT_VERSION)
1504 - Vendor Parameter Protection:
1506 U-Boot considers the values of the environment
1507 variables "serial#" (Board Serial Number) and
1508 "ethaddr" (Ethernet Address) to be parameters that
1509 are set once by the board vendor / manufacturer, and
1510 protects these variables from casual modification by
1511 the user. Once set, these variables are read-only,
1512 and write or delete attempts are rejected. You can
1513 change this behviour:
1515 If CONFIG_ENV_OVERWRITE is #defined in your config
1516 file, the write protection for vendor parameters is
1517 completely disabled. Anybody can change or delete
1520 Alternatively, if you #define _both_ CONFIG_ETHADDR
1521 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1522 ethernet address is installed in the environment,
1523 which can be changed exactly ONCE by the user. [The
1524 serial# is unaffected by this, i. e. it remains
1530 Define this variable to enable the reservation of
1531 "protected RAM", i. e. RAM which is not overwritten
1532 by U-Boot. Define CONFIG_PRAM to hold the number of
1533 kB you want to reserve for pRAM. You can overwrite
1534 this default value by defining an environment
1535 variable "pram" to the number of kB you want to
1536 reserve. Note that the board info structure will
1537 still show the full amount of RAM. If pRAM is
1538 reserved, a new environment variable "mem" will
1539 automatically be defined to hold the amount of
1540 remaining RAM in a form that can be passed as boot
1541 argument to Linux, for instance like that:
1543 setenv bootargs ... mem=\${mem}
1546 This way you can tell Linux not to use this memory,
1547 either, which results in a memory region that will
1548 not be affected by reboots.
1550 *WARNING* If your board configuration uses automatic
1551 detection of the RAM size, you must make sure that
1552 this memory test is non-destructive. So far, the
1553 following board configurations are known to be
1556 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1557 HERMES, IP860, RPXlite, LWMON, LANTEC,
1558 PCU_E, FLAGADM, TQM8260
1563 Define this variable to stop the system in case of a
1564 fatal error, so that you have to reset it manually.
1565 This is probably NOT a good idea for an embedded
1566 system where you want to system to reboot
1567 automatically as fast as possible, but it may be
1568 useful during development since you can try to debug
1569 the conditions that lead to the situation.
1571 CONFIG_NET_RETRY_COUNT
1573 This variable defines the number of retries for
1574 network operations like ARP, RARP, TFTP, or BOOTP
1575 before giving up the operation. If not defined, a
1576 default value of 5 is used.
1580 Timeout waiting for an ARP reply in milliseconds.
1582 - Command Interpreter:
1583 CONFIG_AUTO_COMPLETE
1585 Enable auto completion of commands using TAB.
1587 Note that this feature has NOT been implemented yet
1588 for the "hush" shell.
1593 Define this variable to enable the "hush" shell (from
1594 Busybox) as command line interpreter, thus enabling
1595 powerful command line syntax like
1596 if...then...else...fi conditionals or `&&' and '||'
1597 constructs ("shell scripts").
1599 If undefined, you get the old, much simpler behaviour
1600 with a somewhat smaller memory footprint.
1605 This defines the secondary prompt string, which is
1606 printed when the command interpreter needs more input
1607 to complete a command. Usually "> ".
1611 In the current implementation, the local variables
1612 space and global environment variables space are
1613 separated. Local variables are those you define by
1614 simply typing `name=value'. To access a local
1615 variable later on, you have write `$name' or
1616 `${name}'; to execute the contents of a variable
1617 directly type `$name' at the command prompt.
1619 Global environment variables are those you use
1620 setenv/printenv to work with. To run a command stored
1621 in such a variable, you need to use the run command,
1622 and you must not use the '$' sign to access them.
1624 To store commands and special characters in a
1625 variable, please use double quotation marks
1626 surrounding the whole text of the variable, instead
1627 of the backslashes before semicolons and special
1630 - Commandline Editing and History:
1631 CONFIG_CMDLINE_EDITING
1633 Enable editiong and History functions for interactive
1634 commandline input operations
1636 - Default Environment:
1637 CONFIG_EXTRA_ENV_SETTINGS
1639 Define this to contain any number of null terminated
1640 strings (variable = value pairs) that will be part of
1641 the default environment compiled into the boot image.
1643 For example, place something like this in your
1644 board's config file:
1646 #define CONFIG_EXTRA_ENV_SETTINGS \
1650 Warning: This method is based on knowledge about the
1651 internal format how the environment is stored by the
1652 U-Boot code. This is NOT an official, exported
1653 interface! Although it is unlikely that this format
1654 will change soon, there is no guarantee either.
1655 You better know what you are doing here.
1657 Note: overly (ab)use of the default environment is
1658 discouraged. Make sure to check other ways to preset
1659 the environment like the autoscript function or the
1662 - DataFlash Support:
1663 CONFIG_HAS_DATAFLASH
1665 Defining this option enables DataFlash features and
1666 allows to read/write in Dataflash via the standard
1669 - SystemACE Support:
1672 Adding this option adds support for Xilinx SystemACE
1673 chips attached via some sort of local bus. The address
1674 of the chip must alsh be defined in the
1675 CFG_SYSTEMACE_BASE macro. For example:
1677 #define CONFIG_SYSTEMACE
1678 #define CFG_SYSTEMACE_BASE 0xf0000000
1680 When SystemACE support is added, the "ace" device type
1681 becomes available to the fat commands, i.e. fatls.
1683 - TFTP Fixed UDP Port:
1686 If this is defined, the environment variable tftpsrcp
1687 is used to supply the TFTP UDP source port value.
1688 If tftpsrcp isn't defined, the normal pseudo-random port
1689 number generator is used.
1691 Also, the environment variable tftpdstp is used to supply
1692 the TFTP UDP destination port value. If tftpdstp isn't
1693 defined, the normal port 69 is used.
1695 The purpose for tftpsrcp is to allow a TFTP server to
1696 blindly start the TFTP transfer using the pre-configured
1697 target IP address and UDP port. This has the effect of
1698 "punching through" the (Windows XP) firewall, allowing
1699 the remainder of the TFTP transfer to proceed normally.
1700 A better solution is to properly configure the firewall,
1701 but sometimes that is not allowed.
1703 - Show boot progress:
1704 CONFIG_SHOW_BOOT_PROGRESS
1706 Defining this option allows to add some board-
1707 specific code (calling a user-provided function
1708 "show_boot_progress(int)") that enables you to show
1709 the system's boot progress on some display (for
1710 example, some LED's) on your board. At the moment,
1711 the following checkpoints are implemented:
1713 Legacy uImage format:
1716 1 common/cmd_bootm.c before attempting to boot an image
1717 -1 common/cmd_bootm.c Image header has bad magic number
1718 2 common/cmd_bootm.c Image header has correct magic number
1719 -2 common/cmd_bootm.c Image header has bad checksum
1720 3 common/cmd_bootm.c Image header has correct checksum
1721 -3 common/cmd_bootm.c Image data has bad checksum
1722 4 common/cmd_bootm.c Image data has correct checksum
1723 -4 common/cmd_bootm.c Image is for unsupported architecture
1724 5 common/cmd_bootm.c Architecture check OK
1725 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1726 6 common/cmd_bootm.c Image Type check OK
1727 -6 common/cmd_bootm.c gunzip uncompression error
1728 -7 common/cmd_bootm.c Unimplemented compression type
1729 7 common/cmd_bootm.c Uncompression OK
1730 8 common/cmd_bootm.c No uncompress/copy overwrite error
1731 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1733 9 common/image.c Start initial ramdisk verification
1734 -10 common/image.c Ramdisk header has bad magic number
1735 -11 common/image.c Ramdisk header has bad checksum
1736 10 common/image.c Ramdisk header is OK
1737 -12 common/image.c Ramdisk data has bad checksum
1738 11 common/image.c Ramdisk data has correct checksum
1739 12 common/image.c Ramdisk verification complete, start loading
1740 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1741 13 common/image.c Start multifile image verification
1742 14 common/image.c No initial ramdisk, no multifile, continue.
1744 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1746 -30 lib_ppc/board.c Fatal error, hang the system
1747 -31 post/post.c POST test failed, detected by post_output_backlog()
1748 -32 post/post.c POST test failed, detected by post_run_single()
1750 34 common/cmd_doc.c before loading a Image from a DOC device
1751 -35 common/cmd_doc.c Bad usage of "doc" command
1752 35 common/cmd_doc.c correct usage of "doc" command
1753 -36 common/cmd_doc.c No boot device
1754 36 common/cmd_doc.c correct boot device
1755 -37 common/cmd_doc.c Unknown Chip ID on boot device
1756 37 common/cmd_doc.c correct chip ID found, device available
1757 -38 common/cmd_doc.c Read Error on boot device
1758 38 common/cmd_doc.c reading Image header from DOC device OK
1759 -39 common/cmd_doc.c Image header has bad magic number
1760 39 common/cmd_doc.c Image header has correct magic number
1761 -40 common/cmd_doc.c Error reading Image from DOC device
1762 40 common/cmd_doc.c Image header has correct magic number
1763 41 common/cmd_ide.c before loading a Image from a IDE device
1764 -42 common/cmd_ide.c Bad usage of "ide" command
1765 42 common/cmd_ide.c correct usage of "ide" command
1766 -43 common/cmd_ide.c No boot device
1767 43 common/cmd_ide.c boot device found
1768 -44 common/cmd_ide.c Device not available
1769 44 common/cmd_ide.c Device available
1770 -45 common/cmd_ide.c wrong partition selected
1771 45 common/cmd_ide.c partition selected
1772 -46 common/cmd_ide.c Unknown partition table
1773 46 common/cmd_ide.c valid partition table found
1774 -47 common/cmd_ide.c Invalid partition type
1775 47 common/cmd_ide.c correct partition type
1776 -48 common/cmd_ide.c Error reading Image Header on boot device
1777 48 common/cmd_ide.c reading Image Header from IDE device OK
1778 -49 common/cmd_ide.c Image header has bad magic number
1779 49 common/cmd_ide.c Image header has correct magic number
1780 -50 common/cmd_ide.c Image header has bad checksum
1781 50 common/cmd_ide.c Image header has correct checksum
1782 -51 common/cmd_ide.c Error reading Image from IDE device
1783 51 common/cmd_ide.c reading Image from IDE device OK
1784 52 common/cmd_nand.c before loading a Image from a NAND device
1785 -53 common/cmd_nand.c Bad usage of "nand" command
1786 53 common/cmd_nand.c correct usage of "nand" command
1787 -54 common/cmd_nand.c No boot device
1788 54 common/cmd_nand.c boot device found
1789 -55 common/cmd_nand.c Unknown Chip ID on boot device
1790 55 common/cmd_nand.c correct chip ID found, device available
1791 -56 common/cmd_nand.c Error reading Image Header on boot device
1792 56 common/cmd_nand.c reading Image Header from NAND device OK
1793 -57 common/cmd_nand.c Image header has bad magic number
1794 57 common/cmd_nand.c Image header has correct magic number
1795 -58 common/cmd_nand.c Error reading Image from NAND device
1796 58 common/cmd_nand.c reading Image from NAND device OK
1798 -60 common/env_common.c Environment has a bad CRC, using default
1800 64 net/eth.c starting with Ethernetconfiguration.
1801 -64 net/eth.c no Ethernet found.
1802 65 net/eth.c Ethernet found.
1804 -80 common/cmd_net.c usage wrong
1805 80 common/cmd_net.c before calling NetLoop()
1806 -81 common/cmd_net.c some error in NetLoop() occured
1807 81 common/cmd_net.c NetLoop() back without error
1808 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1809 82 common/cmd_net.c trying automatic boot
1810 83 common/cmd_net.c running autoscript
1811 -83 common/cmd_net.c some error in automatic boot or autoscript
1812 84 common/cmd_net.c end without errors
1817 100 common/cmd_bootm.c Kernel FIT Image has correct format
1818 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1819 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1820 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1821 102 common/cmd_bootm.c Kernel unit name specified
1822 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1823 103 common/cmd_bootm.c Found configuration node
1824 104 common/cmd_bootm.c Got kernel subimage node offset
1825 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1826 105 common/cmd_bootm.c Kernel subimage hash verification OK
1827 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1828 106 common/cmd_bootm.c Architecture check OK
1829 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1830 107 common/cmd_bootm.c Kernel subimge type OK
1831 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1832 108 common/cmd_bootm.c Got kernel subimage data/size
1833 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1834 -109 common/cmd_bootm.c Can't get kernel subimage type
1835 -110 common/cmd_bootm.c Can't get kernel subimage comp
1836 -111 common/cmd_bootm.c Can't get kernel subimage os
1837 -112 common/cmd_bootm.c Can't get kernel subimage load address
1838 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1840 120 common/image.c Start initial ramdisk verification
1841 -120 common/image.c Ramdisk FIT image has incorrect format
1842 121 common/image.c Ramdisk FIT image has correct format
1843 122 common/image.c No Ramdisk subimage unit name, using configuration
1844 -122 common/image.c Can't get configuration for ramdisk subimage
1845 123 common/image.c Ramdisk unit name specified
1846 -124 common/image.c Can't get ramdisk subimage node offset
1847 125 common/image.c Got ramdisk subimage node offset
1848 -125 common/image.c Ramdisk subimage hash verification failed
1849 126 common/image.c Ramdisk subimage hash verification OK
1850 -126 common/image.c Ramdisk subimage for unsupported architecture
1851 127 common/image.c Architecture check OK
1852 -127 common/image.c Can't get ramdisk subimage data/size
1853 128 common/image.c Got ramdisk subimage data/size
1854 129 common/image.c Can't get ramdisk load address
1855 -129 common/image.c Got ramdisk load address
1857 -130 common/cmd_doc.c Icorrect FIT image format
1858 131 common/cmd_doc.c FIT image format OK
1860 -140 common/cmd_ide.c Icorrect FIT image format
1861 141 common/cmd_ide.c FIT image format OK
1863 -150 common/cmd_nand.c Icorrect FIT image format
1864 151 common/cmd_nand.c FIT image format OK
1870 [so far only for SMDK2400 and TRAB boards]
1872 - Modem support endable:
1873 CONFIG_MODEM_SUPPORT
1875 - RTS/CTS Flow control enable:
1878 - Modem debug support:
1879 CONFIG_MODEM_SUPPORT_DEBUG
1881 Enables debugging stuff (char screen[1024], dbg())
1882 for modem support. Useful only with BDI2000.
1884 - Interrupt support (PPC):
1886 There are common interrupt_init() and timer_interrupt()
1887 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1888 for cpu specific initialization. interrupt_init_cpu()
1889 should set decrementer_count to appropriate value. If
1890 cpu resets decrementer automatically after interrupt
1891 (ppc4xx) it should set decrementer_count to zero.
1892 timer_interrupt() calls timer_interrupt_cpu() for cpu
1893 specific handling. If board has watchdog / status_led
1894 / other_activity_monitor it works automatically from
1895 general timer_interrupt().
1899 In the target system modem support is enabled when a
1900 specific key (key combination) is pressed during
1901 power-on. Otherwise U-Boot will boot normally
1902 (autoboot). The key_pressed() fuction is called from
1903 board_init(). Currently key_pressed() is a dummy
1904 function, returning 1 and thus enabling modem
1907 If there are no modem init strings in the
1908 environment, U-Boot proceed to autoboot; the
1909 previous output (banner, info printfs) will be
1912 See also: doc/README.Modem
1915 Configuration Settings:
1916 -----------------------
1918 - CFG_LONGHELP: Defined when you want long help messages included;
1919 undefine this when you're short of memory.
1921 - CFG_PROMPT: This is what U-Boot prints on the console to
1922 prompt for user input.
1924 - CFG_CBSIZE: Buffer size for input from the Console
1926 - CFG_PBSIZE: Buffer size for Console output
1928 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1930 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1931 the application (usually a Linux kernel) when it is
1934 - CFG_BAUDRATE_TABLE:
1935 List of legal baudrate settings for this board.
1937 - CFG_CONSOLE_INFO_QUIET
1938 Suppress display of console information at boot.
1940 - CFG_CONSOLE_IS_IN_ENV
1941 If the board specific function
1942 extern int overwrite_console (void);
1943 returns 1, the stdin, stderr and stdout are switched to the
1944 serial port, else the settings in the environment are used.
1946 - CFG_CONSOLE_OVERWRITE_ROUTINE
1947 Enable the call to overwrite_console().
1949 - CFG_CONSOLE_ENV_OVERWRITE
1950 Enable overwrite of previous console environment settings.
1952 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1953 Begin and End addresses of the area used by the
1957 Enable an alternate, more extensive memory test.
1959 - CFG_MEMTEST_SCRATCH:
1960 Scratch address used by the alternate memory test
1961 You only need to set this if address zero isn't writeable
1963 - CFG_MEM_TOP_HIDE (PPC only):
1964 If CFG_MEM_TOP_HIDE is defined in the board config header,
1965 this specified memory area will get subtracted from the top
1966 (end) of ram and won't get "touched" at all by U-Boot. By
1967 fixing up gd->ram_size the Linux kernel should gets passed
1968 the now "corrected" memory size and won't touch it either.
1969 This should work for arch/ppc and arch/powerpc. Only Linux
1970 board ports in arch/powerpc with bootwrapper support that
1971 recalculate the memory size from the SDRAM controller setup
1972 will have to get fixed in Linux additionally.
1974 This option can be used as a workaround for the 440EPx/GRx
1975 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1978 WARNING: Please make sure that this value is a multiple of
1979 the Linux page size (normally 4k). If this is not the case,
1980 then the end address of the Linux memory will be located at a
1981 non page size aligned address and this could cause major
1984 - CFG_TFTP_LOADADDR:
1985 Default load address for network file downloads
1987 - CFG_LOADS_BAUD_CHANGE:
1988 Enable temporary baudrate change while serial download
1991 Physical start address of SDRAM. _Must_ be 0 here.
1994 Physical start address of Motherboard I/O (if using a
1998 Physical start address of Flash memory.
2001 Physical start address of boot monitor code (set by
2002 make config files to be same as the text base address
2003 (TEXT_BASE) used when linking) - same as
2004 CFG_FLASH_BASE when booting from flash.
2007 Size of memory reserved for monitor code, used to
2008 determine _at_compile_time_ (!) if the environment is
2009 embedded within the U-Boot image, or in a separate
2013 Size of DRAM reserved for malloc() use.
2016 Normally compressed uImages are limited to an
2017 uncompressed size of 8 MBytes. If this is not enough,
2018 you can define CFG_BOOTM_LEN in your board config file
2019 to adjust this setting to your needs.
2022 Maximum size of memory mapped by the startup code of
2023 the Linux kernel; all data that must be processed by
2024 the Linux kernel (bd_info, boot arguments, FDT blob if
2025 used) must be put below this limit, unless "bootm_low"
2026 enviroment variable is defined and non-zero. In such case
2027 all data for the Linux kernel must be between "bootm_low"
2028 and "bootm_low" + CFG_BOOTMAPSZ.
2030 - CFG_MAX_FLASH_BANKS:
2031 Max number of Flash memory banks
2033 - CFG_MAX_FLASH_SECT:
2034 Max number of sectors on a Flash chip
2036 - CFG_FLASH_ERASE_TOUT:
2037 Timeout for Flash erase operations (in ms)
2039 - CFG_FLASH_WRITE_TOUT:
2040 Timeout for Flash write operations (in ms)
2042 - CFG_FLASH_LOCK_TOUT
2043 Timeout for Flash set sector lock bit operation (in ms)
2045 - CFG_FLASH_UNLOCK_TOUT
2046 Timeout for Flash clear lock bits operation (in ms)
2048 - CFG_FLASH_PROTECTION
2049 If defined, hardware flash sectors protection is used
2050 instead of U-Boot software protection.
2052 - CFG_DIRECT_FLASH_TFTP:
2054 Enable TFTP transfers directly to flash memory;
2055 without this option such a download has to be
2056 performed in two steps: (1) download to RAM, and (2)
2057 copy from RAM to flash.
2059 The two-step approach is usually more reliable, since
2060 you can check if the download worked before you erase
2061 the flash, but in some situations (when sytem RAM is
2062 too limited to allow for a tempory copy of the
2063 downloaded image) this option may be very useful.
2066 Define if the flash driver uses extra elements in the
2067 common flash structure for storing flash geometry.
2069 - CFG_FLASH_CFI_DRIVER
2070 This option also enables the building of the cfi_flash driver
2071 in the drivers directory
2073 - CFG_FLASH_USE_BUFFER_WRITE
2074 Use buffered writes to flash.
2076 - CONFIG_FLASH_SPANSION_S29WS_N
2077 s29ws-n MirrorBit flash has non-standard addresses for buffered
2080 - CFG_FLASH_QUIET_TEST
2081 If this option is defined, the common CFI flash doesn't
2082 print it's warning upon not recognized FLASH banks. This
2083 is useful, if some of the configured banks are only
2084 optionally available.
2086 - CONFIG_FLASH_SHOW_PROGRESS
2087 If defined (must be an integer), print out countdown
2088 digits and dots. Recommended value: 45 (9..1) for 80
2089 column displays, 15 (3..1) for 40 column displays.
2091 - CFG_RX_ETH_BUFFER:
2092 Defines the number of ethernet receive buffers. On some
2093 ethernet controllers it is recommended to set this value
2094 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2095 buffers can be full shortly after enabling the interface
2096 on high ethernet traffic.
2097 Defaults to 4 if not defined.
2099 The following definitions that deal with the placement and management
2100 of environment data (variable area); in general, we support the
2101 following configurations:
2103 - CFG_ENV_IS_IN_FLASH:
2105 Define this if the environment is in flash memory.
2107 a) The environment occupies one whole flash sector, which is
2108 "embedded" in the text segment with the U-Boot code. This
2109 happens usually with "bottom boot sector" or "top boot
2110 sector" type flash chips, which have several smaller
2111 sectors at the start or the end. For instance, such a
2112 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2113 such a case you would place the environment in one of the
2114 4 kB sectors - with U-Boot code before and after it. With
2115 "top boot sector" type flash chips, you would put the
2116 environment in one of the last sectors, leaving a gap
2117 between U-Boot and the environment.
2121 Offset of environment data (variable area) to the
2122 beginning of flash memory; for instance, with bottom boot
2123 type flash chips the second sector can be used: the offset
2124 for this sector is given here.
2126 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2130 This is just another way to specify the start address of
2131 the flash sector containing the environment (instead of
2134 - CFG_ENV_SECT_SIZE:
2136 Size of the sector containing the environment.
2139 b) Sometimes flash chips have few, equal sized, BIG sectors.
2140 In such a case you don't want to spend a whole sector for
2145 If you use this in combination with CFG_ENV_IS_IN_FLASH
2146 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2147 of this flash sector for the environment. This saves
2148 memory for the RAM copy of the environment.
2150 It may also save flash memory if you decide to use this
2151 when your environment is "embedded" within U-Boot code,
2152 since then the remainder of the flash sector could be used
2153 for U-Boot code. It should be pointed out that this is
2154 STRONGLY DISCOURAGED from a robustness point of view:
2155 updating the environment in flash makes it always
2156 necessary to erase the WHOLE sector. If something goes
2157 wrong before the contents has been restored from a copy in
2158 RAM, your target system will be dead.
2160 - CFG_ENV_ADDR_REDUND
2163 These settings describe a second storage area used to hold
2164 a redundand copy of the environment data, so that there is
2165 a valid backup copy in case there is a power failure during
2166 a "saveenv" operation.
2168 BE CAREFUL! Any changes to the flash layout, and some changes to the
2169 source code will make it necessary to adapt <board>/u-boot.lds*
2173 - CFG_ENV_IS_IN_NVRAM:
2175 Define this if you have some non-volatile memory device
2176 (NVRAM, battery buffered SRAM) which you want to use for the
2182 These two #defines are used to determin the memory area you
2183 want to use for environment. It is assumed that this memory
2184 can just be read and written to, without any special
2187 BE CAREFUL! The first access to the environment happens quite early
2188 in U-Boot initalization (when we try to get the setting of for the
2189 console baudrate). You *MUST* have mappend your NVRAM area then, or
2192 Please note that even with NVRAM we still use a copy of the
2193 environment in RAM: we could work on NVRAM directly, but we want to
2194 keep settings there always unmodified except somebody uses "saveenv"
2195 to save the current settings.
2198 - CFG_ENV_IS_IN_EEPROM:
2200 Use this if you have an EEPROM or similar serial access
2201 device and a driver for it.
2206 These two #defines specify the offset and size of the
2207 environment area within the total memory of your EEPROM.
2209 - CFG_I2C_EEPROM_ADDR:
2210 If defined, specified the chip address of the EEPROM device.
2211 The default address is zero.
2213 - CFG_EEPROM_PAGE_WRITE_BITS:
2214 If defined, the number of bits used to address bytes in a
2215 single page in the EEPROM device. A 64 byte page, for example
2216 would require six bits.
2218 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2219 If defined, the number of milliseconds to delay between
2220 page writes. The default is zero milliseconds.
2222 - CFG_I2C_EEPROM_ADDR_LEN:
2223 The length in bytes of the EEPROM memory array address. Note
2224 that this is NOT the chip address length!
2226 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2227 EEPROM chips that implement "address overflow" are ones
2228 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2229 address and the extra bits end up in the "chip address" bit
2230 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2233 Note that we consider the length of the address field to
2234 still be one byte because the extra address bits are hidden
2235 in the chip address.
2238 The size in bytes of the EEPROM device.
2241 - CFG_ENV_IS_IN_DATAFLASH:
2243 Define this if you have a DataFlash memory device which you
2244 want to use for the environment.
2250 These three #defines specify the offset and size of the
2251 environment area within the total memory of your DataFlash placed
2252 at the specified address.
2254 - CFG_ENV_IS_IN_NAND:
2256 Define this if you have a NAND device which you want to use
2257 for the environment.
2262 These two #defines specify the offset and size of the environment
2263 area within the first NAND device.
2265 - CFG_ENV_OFFSET_REDUND
2267 This setting describes a second storage area of CFG_ENV_SIZE
2268 size used to hold a redundant copy of the environment data,
2269 so that there is a valid backup copy in case there is a
2270 power failure during a "saveenv" operation.
2272 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2273 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2274 the NAND devices block size.
2276 - CFG_SPI_INIT_OFFSET
2278 Defines offset to the initial SPI buffer area in DPRAM. The
2279 area is used at an early stage (ROM part) if the environment
2280 is configured to reside in the SPI EEPROM: We need a 520 byte
2281 scratch DPRAM area. It is used between the two initialization
2282 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2283 to be a good choice since it makes it far enough from the
2284 start of the data area as well as from the stack pointer.
2286 Please note that the environment is read-only until the monitor
2287 has been relocated to RAM and a RAM copy of the environment has been
2288 created; also, when using EEPROM you will have to use getenv_r()
2289 until then to read environment variables.
2291 The environment is protected by a CRC32 checksum. Before the monitor
2292 is relocated into RAM, as a result of a bad CRC you will be working
2293 with the compiled-in default environment - *silently*!!! [This is
2294 necessary, because the first environment variable we need is the
2295 "baudrate" setting for the console - if we have a bad CRC, we don't
2296 have any device yet where we could complain.]
2298 Note: once the monitor has been relocated, then it will complain if
2299 the default environment is used; a new CRC is computed as soon as you
2300 use the "saveenv" command to store a valid environment.
2302 - CFG_FAULT_ECHO_LINK_DOWN:
2303 Echo the inverted Ethernet link state to the fault LED.
2305 Note: If this option is active, then CFG_FAULT_MII_ADDR
2306 also needs to be defined.
2308 - CFG_FAULT_MII_ADDR:
2309 MII address of the PHY to check for the Ethernet link state.
2311 - CFG_64BIT_VSPRINTF:
2312 Makes vsprintf (and all *printf functions) support printing
2313 of 64bit values by using the L quantifier
2315 - CFG_64BIT_STRTOUL:
2316 Adds simple_strtoull that returns a 64bit value
2318 Low Level (hardware related) configuration options:
2319 ---------------------------------------------------
2321 - CFG_CACHELINE_SIZE:
2322 Cache Line Size of the CPU.
2325 Default address of the IMMR after system reset.
2327 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2328 and RPXsuper) to be able to adjust the position of
2329 the IMMR register after a reset.
2331 - Floppy Disk Support:
2332 CFG_FDC_DRIVE_NUMBER
2334 the default drive number (default value 0)
2338 defines the spacing between fdc chipset registers
2343 defines the offset of register from address. It
2344 depends on which part of the data bus is connected to
2345 the fdc chipset. (default value 0)
2347 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2348 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2351 if CFG_FDC_HW_INIT is defined, then the function
2352 fdc_hw_init() is called at the beginning of the FDC
2353 setup. fdc_hw_init() must be provided by the board
2354 source code. It is used to make hardware dependant
2357 - CFG_IMMR: Physical address of the Internal Memory.
2358 DO NOT CHANGE unless you know exactly what you're
2359 doing! (11-4) [MPC8xx/82xx systems only]
2361 - CFG_INIT_RAM_ADDR:
2363 Start address of memory area that can be used for
2364 initial data and stack; please note that this must be
2365 writable memory that is working WITHOUT special
2366 initialization, i. e. you CANNOT use normal RAM which
2367 will become available only after programming the
2368 memory controller and running certain initialization
2371 U-Boot uses the following memory types:
2372 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2373 - MPC824X: data cache
2374 - PPC4xx: data cache
2376 - CFG_GBL_DATA_OFFSET:
2378 Offset of the initial data structure in the memory
2379 area defined by CFG_INIT_RAM_ADDR. Usually
2380 CFG_GBL_DATA_OFFSET is chosen such that the initial
2381 data is located at the end of the available space
2382 (sometimes written as (CFG_INIT_RAM_END -
2383 CFG_INIT_DATA_SIZE), and the initial stack is just
2384 below that area (growing from (CFG_INIT_RAM_ADDR +
2385 CFG_GBL_DATA_OFFSET) downward.
2388 On the MPC824X (or other systems that use the data
2389 cache for initial memory) the address chosen for
2390 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2391 point to an otherwise UNUSED address space between
2392 the top of RAM and the start of the PCI space.
2394 - CFG_SIUMCR: SIU Module Configuration (11-6)
2396 - CFG_SYPCR: System Protection Control (11-9)
2398 - CFG_TBSCR: Time Base Status and Control (11-26)
2400 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2402 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2404 - CFG_SCCR: System Clock and reset Control Register (15-27)
2406 - CFG_OR_TIMING_SDRAM:
2410 periodic timer for refresh
2412 - CFG_DER: Debug Event Register (37-47)
2414 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2415 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2416 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2418 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2420 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2421 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2422 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2423 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2425 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2426 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2427 Machine Mode Register and Memory Periodic Timer
2428 Prescaler definitions (SDRAM timing)
2430 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2431 enable I2C microcode relocation patch (MPC8xx);
2432 define relocation offset in DPRAM [DSP2]
2434 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2435 enable SMC microcode relocation patch (MPC8xx);
2436 define relocation offset in DPRAM [SMC1]
2438 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2439 enable SPI microcode relocation patch (MPC8xx);
2440 define relocation offset in DPRAM [SCC4]
2443 Use OSCM clock mode on MBX8xx board. Be careful,
2444 wrong setting might damage your board. Read
2445 doc/README.MBX before setting this variable!
2447 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2448 Offset of the bootmode word in DPRAM used by post
2449 (Power On Self Tests). This definition overrides
2450 #define'd default value in commproc.h resp.
2453 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2454 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2455 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2456 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2457 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2458 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2459 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2460 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2461 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2464 Get DDR timing information from an I2C EEPROM. Common
2465 with pluggable memory modules such as SODIMMs
2468 I2C address of the SPD EEPROM
2471 If SPD EEPROM is on an I2C bus other than the first
2472 one, specify here. Note that the value must resolve
2473 to something your driver can deal with.
2475 - CFG_83XX_DDR_USES_CS0
2476 Only for 83xx systems. If specified, then DDR should
2477 be configured using CS0 and CS1 instead of CS2 and CS3.
2479 - CFG_83XX_DDR_USES_CS0
2480 Only for 83xx systems. If specified, then DDR should
2481 be configured using CS0 and CS1 instead of CS2 and CS3.
2483 - CONFIG_ETHER_ON_FEC[12]
2484 Define to enable FEC[12] on a 8xx series processor.
2486 - CONFIG_FEC[12]_PHY
2487 Define to the hardcoded PHY address which corresponds
2488 to the given FEC; i. e.
2489 #define CONFIG_FEC1_PHY 4
2490 means that the PHY with address 4 is connected to FEC1
2492 When set to -1, means to probe for first available.
2494 - CONFIG_FEC[12]_PHY_NORXERR
2495 The PHY does not have a RXERR line (RMII only).
2496 (so program the FEC to ignore it).
2499 Enable RMII mode for all FECs.
2500 Note that this is a global option, we can't
2501 have one FEC in standard MII mode and another in RMII mode.
2503 - CONFIG_CRC32_VERIFY
2504 Add a verify option to the crc32 command.
2507 => crc32 -v <address> <count> <crc32>
2509 Where address/count indicate a memory area
2510 and crc32 is the correct crc32 which the
2514 Add the "loopw" memory command. This only takes effect if
2515 the memory commands are activated globally (CONFIG_CMD_MEM).
2518 Add the "mdc" and "mwc" memory commands. These are cyclic
2523 This command will print 4 bytes (10,11,12,13) each 500 ms.
2525 => mwc.l 100 12345678 10
2526 This command will write 12345678 to address 100 all 10 ms.
2528 This only takes effect if the memory commands are activated
2529 globally (CONFIG_CMD_MEM).
2531 - CONFIG_SKIP_LOWLEVEL_INIT
2532 - CONFIG_SKIP_RELOCATE_UBOOT
2534 [ARM only] If these variables are defined, then
2535 certain low level initializations (like setting up
2536 the memory controller) are omitted and/or U-Boot does
2537 not relocate itself into RAM.
2538 Normally these variables MUST NOT be defined. The
2539 only exception is when U-Boot is loaded (to RAM) by
2540 some other boot loader or by a debugger which
2541 performs these intializations itself.
2544 Building the Software:
2545 ======================
2547 Building U-Boot has been tested in several native build environments
2548 and in many different cross environments. Of course we cannot support
2549 all possibly existing versions of cross development tools in all
2550 (potentially obsolete) versions. In case of tool chain problems we
2551 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2552 which is extensively used to build and test U-Boot.
2554 If you are not using a native environment, it is assumed that you
2555 have GNU cross compiling tools available in your path. In this case,
2556 you must set the environment variable CROSS_COMPILE in your shell.
2557 Note that no changes to the Makefile or any other source files are
2558 necessary. For example using the ELDK on a 4xx CPU, please enter:
2560 $ CROSS_COMPILE=ppc_4xx-
2561 $ export CROSS_COMPILE
2563 U-Boot is intended to be simple to build. After installing the
2564 sources you must configure U-Boot for one specific board type. This
2569 where "NAME_config" is the name of one of the existing configu-
2570 rations; see the main Makefile for supported names.
2572 Note: for some board special configuration names may exist; check if
2573 additional information is available from the board vendor; for
2574 instance, the TQM823L systems are available without (standard)
2575 or with LCD support. You can select such additional "features"
2576 when chosing the configuration, i. e.
2579 - will configure for a plain TQM823L, i. e. no LCD support
2581 make TQM823L_LCD_config
2582 - will configure for a TQM823L with U-Boot console on LCD
2587 Finally, type "make all", and you should get some working U-Boot
2588 images ready for download to / installation on your system:
2590 - "u-boot.bin" is a raw binary image
2591 - "u-boot" is an image in ELF binary format
2592 - "u-boot.srec" is in Motorola S-Record format
2594 By default the build is performed locally and the objects are saved
2595 in the source directory. One of the two methods can be used to change
2596 this behavior and build U-Boot to some external directory:
2598 1. Add O= to the make command line invocations:
2600 make O=/tmp/build distclean
2601 make O=/tmp/build NAME_config
2602 make O=/tmp/build all
2604 2. Set environment variable BUILD_DIR to point to the desired location:
2606 export BUILD_DIR=/tmp/build
2611 Note that the command line "O=" setting overrides the BUILD_DIR environment
2615 Please be aware that the Makefiles assume you are using GNU make, so
2616 for instance on NetBSD you might need to use "gmake" instead of
2620 If the system board that you have is not listed, then you will need
2621 to port U-Boot to your hardware platform. To do this, follow these
2624 1. Add a new configuration option for your board to the toplevel
2625 "Makefile" and to the "MAKEALL" script, using the existing
2626 entries as examples. Note that here and at many other places
2627 boards and other names are listed in alphabetical sort order. Please
2629 2. Create a new directory to hold your board specific code. Add any
2630 files you need. In your board directory, you will need at least
2631 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2632 3. Create a new configuration file "include/configs/<board>.h" for
2634 3. If you're porting U-Boot to a new CPU, then also create a new
2635 directory to hold your CPU specific code. Add any files you need.
2636 4. Run "make <board>_config" with your new name.
2637 5. Type "make", and you should get a working "u-boot.srec" file
2638 to be installed on your target system.
2639 6. Debug and solve any problems that might arise.
2640 [Of course, this last step is much harder than it sounds.]
2643 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2644 ==============================================================
2646 If you have modified U-Boot sources (for instance added a new board
2647 or support for new devices, a new CPU, etc.) you are expected to
2648 provide feedback to the other developers. The feedback normally takes
2649 the form of a "patch", i. e. a context diff against a certain (latest
2650 official or latest in the git repository) version of U-Boot sources.
2652 But before you submit such a patch, please verify that your modifi-
2653 cation did not break existing code. At least make sure that *ALL* of
2654 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2655 just run the "MAKEALL" script, which will configure and build U-Boot
2656 for ALL supported system. Be warned, this will take a while. You can
2657 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2658 environment variable to the script, i. e. to use the ELDK cross tools
2661 CROSS_COMPILE=ppc_8xx- MAKEALL
2663 or to build on a native PowerPC system you can type
2665 CROSS_COMPILE=' ' MAKEALL
2667 When using the MAKEALL script, the default behaviour is to build
2668 U-Boot in the source directory. This location can be changed by
2669 setting the BUILD_DIR environment variable. Also, for each target
2670 built, the MAKEALL script saves two log files (<target>.ERR and
2671 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2672 location can be changed by setting the MAKEALL_LOGDIR environment
2673 variable. For example:
2675 export BUILD_DIR=/tmp/build
2676 export MAKEALL_LOGDIR=/tmp/log
2677 CROSS_COMPILE=ppc_8xx- MAKEALL
2679 With the above settings build objects are saved in the /tmp/build,
2680 log files are saved in the /tmp/log and the source tree remains clean
2681 during the whole build process.
2684 See also "U-Boot Porting Guide" below.
2687 Monitor Commands - Overview:
2688 ============================
2690 go - start application at address 'addr'
2691 run - run commands in an environment variable
2692 bootm - boot application image from memory
2693 bootp - boot image via network using BootP/TFTP protocol
2694 tftpboot- boot image via network using TFTP protocol
2695 and env variables "ipaddr" and "serverip"
2696 (and eventually "gatewayip")
2697 rarpboot- boot image via network using RARP/TFTP protocol
2698 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2699 loads - load S-Record file over serial line
2700 loadb - load binary file over serial line (kermit mode)
2702 mm - memory modify (auto-incrementing)
2703 nm - memory modify (constant address)
2704 mw - memory write (fill)
2706 cmp - memory compare
2707 crc32 - checksum calculation
2708 imd - i2c memory display
2709 imm - i2c memory modify (auto-incrementing)
2710 inm - i2c memory modify (constant address)
2711 imw - i2c memory write (fill)
2712 icrc32 - i2c checksum calculation
2713 iprobe - probe to discover valid I2C chip addresses
2714 iloop - infinite loop on address range
2715 isdram - print SDRAM configuration information
2716 sspi - SPI utility commands
2717 base - print or set address offset
2718 printenv- print environment variables
2719 setenv - set environment variables
2720 saveenv - save environment variables to persistent storage
2721 protect - enable or disable FLASH write protection
2722 erase - erase FLASH memory
2723 flinfo - print FLASH memory information
2724 bdinfo - print Board Info structure
2725 iminfo - print header information for application image
2726 coninfo - print console devices and informations
2727 ide - IDE sub-system
2728 loop - infinite loop on address range
2729 loopw - infinite write loop on address range
2730 mtest - simple RAM test
2731 icache - enable or disable instruction cache
2732 dcache - enable or disable data cache
2733 reset - Perform RESET of the CPU
2734 echo - echo args to console
2735 version - print monitor version
2736 help - print online help
2737 ? - alias for 'help'
2740 Monitor Commands - Detailed Description:
2741 ========================================
2745 For now: just type "help <command>".
2748 Environment Variables:
2749 ======================
2751 U-Boot supports user configuration using Environment Variables which
2752 can be made persistent by saving to Flash memory.
2754 Environment Variables are set using "setenv", printed using
2755 "printenv", and saved to Flash using "saveenv". Using "setenv"
2756 without a value can be used to delete a variable from the
2757 environment. As long as you don't save the environment you are
2758 working with an in-memory copy. In case the Flash area containing the
2759 environment is erased by accident, a default environment is provided.
2761 Some configuration options can be set using Environment Variables:
2763 baudrate - see CONFIG_BAUDRATE
2765 bootdelay - see CONFIG_BOOTDELAY
2767 bootcmd - see CONFIG_BOOTCOMMAND
2769 bootargs - Boot arguments when booting an RTOS image
2771 bootfile - Name of the image to load with TFTP
2773 bootm_low - Memory range available for image processing in the bootm
2774 command can be restricted. This variable is given as
2775 a hexadecimal number and defines lowest address allowed
2776 for use by the bootm command. See also "bootm_size"
2777 environment variable. Address defined by "bootm_low" is
2778 also the base of the initial memory mapping for the Linux
2779 kernel -- see the descripton of CFG_BOOTMAPSZ.
2781 bootm_size - Memory range available for image processing in the bootm
2782 command can be restricted. This variable is given as
2783 a hexadecimal number and defines the size of the region
2784 allowed for use by the bootm command. See also "bootm_low"
2785 environment variable.
2787 autoload - if set to "no" (any string beginning with 'n'),
2788 "bootp" will just load perform a lookup of the
2789 configuration from the BOOTP server, but not try to
2790 load any image using TFTP
2792 autoscript - if set to "yes" commands like "loadb", "loady",
2793 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2794 to automatically run script images (by internally
2795 calling "autoscript").
2797 autoscript_uname - if script image is in a format (FIT) this
2798 variable is used to get script subimage unit name.
2800 autostart - if set to "yes", an image loaded using the "bootp",
2801 "rarpboot", "tftpboot" or "diskboot" commands will
2802 be automatically started (by internally calling
2805 If set to "no", a standalone image passed to the
2806 "bootm" command will be copied to the load address
2807 (and eventually uncompressed), but NOT be started.
2808 This can be used to load and uncompress arbitrary
2811 i2cfast - (PPC405GP|PPC405EP only)
2812 if set to 'y' configures Linux I2C driver for fast
2813 mode (400kHZ). This environment variable is used in
2814 initialization code. So, for changes to be effective
2815 it must be saved and board must be reset.
2817 initrd_high - restrict positioning of initrd images:
2818 If this variable is not set, initrd images will be
2819 copied to the highest possible address in RAM; this
2820 is usually what you want since it allows for
2821 maximum initrd size. If for some reason you want to
2822 make sure that the initrd image is loaded below the
2823 CFG_BOOTMAPSZ limit, you can set this environment
2824 variable to a value of "no" or "off" or "0".
2825 Alternatively, you can set it to a maximum upper
2826 address to use (U-Boot will still check that it
2827 does not overwrite the U-Boot stack and data).
2829 For instance, when you have a system with 16 MB
2830 RAM, and want to reserve 4 MB from use by Linux,
2831 you can do this by adding "mem=12M" to the value of
2832 the "bootargs" variable. However, now you must make
2833 sure that the initrd image is placed in the first
2834 12 MB as well - this can be done with
2836 setenv initrd_high 00c00000
2838 If you set initrd_high to 0xFFFFFFFF, this is an
2839 indication to U-Boot that all addresses are legal
2840 for the Linux kernel, including addresses in flash
2841 memory. In this case U-Boot will NOT COPY the
2842 ramdisk at all. This may be useful to reduce the
2843 boot time on your system, but requires that this
2844 feature is supported by your Linux kernel.
2846 ipaddr - IP address; needed for tftpboot command
2848 loadaddr - Default load address for commands like "bootp",
2849 "rarpboot", "tftpboot", "loadb" or "diskboot"
2851 loads_echo - see CONFIG_LOADS_ECHO
2853 serverip - TFTP server IP address; needed for tftpboot command
2855 bootretry - see CONFIG_BOOT_RETRY_TIME
2857 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2859 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2861 ethprime - When CONFIG_NET_MULTI is enabled controls which
2862 interface is used first.
2864 ethact - When CONFIG_NET_MULTI is enabled controls which
2865 interface is currently active. For example you
2866 can do the following
2868 => setenv ethact FEC ETHERNET
2869 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2870 => setenv ethact SCC ETHERNET
2871 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2873 ethrotate - When set to "no" U-Boot does not go through all
2874 available network interfaces.
2875 It just stays at the currently selected interface.
2877 netretry - When set to "no" each network operation will
2878 either succeed or fail without retrying.
2879 When set to "once" the network operation will
2880 fail when all the available network interfaces
2881 are tried once without success.
2882 Useful on scripts which control the retry operation
2885 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2886 if set load address for the npe microcode
2888 tftpsrcport - If this is set, the value is used for TFTP's
2891 tftpdstport - If this is set, the value is used for TFTP's UDP
2892 destination port instead of the Well Know Port 69.
2894 vlan - When set to a value < 4095 the traffic over
2895 ethernet is encapsulated/received over 802.1q
2898 The following environment variables may be used and automatically
2899 updated by the network boot commands ("bootp" and "rarpboot"),
2900 depending the information provided by your boot server:
2902 bootfile - see above
2903 dnsip - IP address of your Domain Name Server
2904 dnsip2 - IP address of your secondary Domain Name Server
2905 gatewayip - IP address of the Gateway (Router) to use
2906 hostname - Target hostname
2908 netmask - Subnet Mask
2909 rootpath - Pathname of the root filesystem on the NFS server
2910 serverip - see above
2913 There are two special Environment Variables:
2915 serial# - contains hardware identification information such
2916 as type string and/or serial number
2917 ethaddr - Ethernet address
2919 These variables can be set only once (usually during manufacturing of
2920 the board). U-Boot refuses to delete or overwrite these variables
2921 once they have been set once.
2924 Further special Environment Variables:
2926 ver - Contains the U-Boot version string as printed
2927 with the "version" command. This variable is
2928 readonly (see CONFIG_VERSION_VARIABLE).
2931 Please note that changes to some configuration parameters may take
2932 only effect after the next boot (yes, that's just like Windoze :-).
2935 Command Line Parsing:
2936 =====================
2938 There are two different command line parsers available with U-Boot:
2939 the old "simple" one, and the much more powerful "hush" shell:
2941 Old, simple command line parser:
2942 --------------------------------
2944 - supports environment variables (through setenv / saveenv commands)
2945 - several commands on one line, separated by ';'
2946 - variable substitution using "... ${name} ..." syntax
2947 - special characters ('$', ';') can be escaped by prefixing with '\',
2949 setenv bootcmd bootm \${address}
2950 - You can also escape text by enclosing in single apostrophes, for example:
2951 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2956 - similar to Bourne shell, with control structures like
2957 if...then...else...fi, for...do...done; while...do...done,
2958 until...do...done, ...
2959 - supports environment ("global") variables (through setenv / saveenv
2960 commands) and local shell variables (through standard shell syntax
2961 "name=value"); only environment variables can be used with "run"
2967 (1) If a command line (or an environment variable executed by a "run"
2968 command) contains several commands separated by semicolon, and
2969 one of these commands fails, then the remaining commands will be
2972 (2) If you execute several variables with one call to run (i. e.
2973 calling run with a list af variables as arguments), any failing
2974 command will cause "run" to terminate, i. e. the remaining
2975 variables are not executed.
2977 Note for Redundant Ethernet Interfaces:
2978 =======================================
2980 Some boards come with redundant ethernet interfaces; U-Boot supports
2981 such configurations and is capable of automatic selection of a
2982 "working" interface when needed. MAC assignment works as follows:
2984 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2985 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2986 "eth1addr" (=>eth1), "eth2addr", ...
2988 If the network interface stores some valid MAC address (for instance
2989 in SROM), this is used as default address if there is NO correspon-
2990 ding setting in the environment; if the corresponding environment
2991 variable is set, this overrides the settings in the card; that means:
2993 o If the SROM has a valid MAC address, and there is no address in the
2994 environment, the SROM's address is used.
2996 o If there is no valid address in the SROM, and a definition in the
2997 environment exists, then the value from the environment variable is
3000 o If both the SROM and the environment contain a MAC address, and
3001 both addresses are the same, this MAC address is used.
3003 o If both the SROM and the environment contain a MAC address, and the
3004 addresses differ, the value from the environment is used and a
3007 o If neither SROM nor the environment contain a MAC address, an error
3014 U-Boot is capable of booting (and performing other auxiliary operations on)
3015 images in two formats:
3017 New uImage format (FIT)
3018 -----------------------
3020 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3021 to Flattened Device Tree). It allows the use of images with multiple
3022 components (several kernels, ramdisks, etc.), with contents protected by
3023 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3029 Old image format is based on binary files which can be basically anything,
3030 preceded by a special header; see the definitions in include/image.h for
3031 details; basically, the header defines the following image properties:
3033 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3034 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3035 LynxOS, pSOS, QNX, RTEMS, ARTOS;
3036 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
3037 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3038 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3039 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3040 * Compression Type (uncompressed, gzip, bzip2)
3046 The header is marked by a special Magic Number, and both the header
3047 and the data portions of the image are secured against corruption by
3054 Although U-Boot should support any OS or standalone application
3055 easily, the main focus has always been on Linux during the design of
3058 U-Boot includes many features that so far have been part of some
3059 special "boot loader" code within the Linux kernel. Also, any
3060 "initrd" images to be used are no longer part of one big Linux image;
3061 instead, kernel and "initrd" are separate images. This implementation
3062 serves several purposes:
3064 - the same features can be used for other OS or standalone
3065 applications (for instance: using compressed images to reduce the
3066 Flash memory footprint)
3068 - it becomes much easier to port new Linux kernel versions because
3069 lots of low-level, hardware dependent stuff are done by U-Boot
3071 - the same Linux kernel image can now be used with different "initrd"
3072 images; of course this also means that different kernel images can
3073 be run with the same "initrd". This makes testing easier (you don't
3074 have to build a new "zImage.initrd" Linux image when you just
3075 change a file in your "initrd"). Also, a field-upgrade of the
3076 software is easier now.
3082 Porting Linux to U-Boot based systems:
3083 ---------------------------------------
3085 U-Boot cannot save you from doing all the necessary modifications to
3086 configure the Linux device drivers for use with your target hardware
3087 (no, we don't intend to provide a full virtual machine interface to
3090 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3092 Just make sure your machine specific header file (for instance
3093 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3094 Information structure as we define in include/u-boot.h, and make
3095 sure that your definition of IMAP_ADDR uses the same value as your
3096 U-Boot configuration in CFG_IMMR.
3099 Configuring the Linux kernel:
3100 -----------------------------
3102 No specific requirements for U-Boot. Make sure you have some root
3103 device (initial ramdisk, NFS) for your target system.
3106 Building a Linux Image:
3107 -----------------------
3109 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3110 not used. If you use recent kernel source, a new build target
3111 "uImage" will exist which automatically builds an image usable by
3112 U-Boot. Most older kernels also have support for a "pImage" target,
3113 which was introduced for our predecessor project PPCBoot and uses a
3114 100% compatible format.
3123 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3124 encapsulate a compressed Linux kernel image with header information,
3125 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3127 * build a standard "vmlinux" kernel image (in ELF binary format):
3129 * convert the kernel into a raw binary image:
3131 ${CROSS_COMPILE}-objcopy -O binary \
3132 -R .note -R .comment \
3133 -S vmlinux linux.bin
3135 * compress the binary image:
3139 * package compressed binary image for U-Boot:
3141 mkimage -A ppc -O linux -T kernel -C gzip \
3142 -a 0 -e 0 -n "Linux Kernel Image" \
3143 -d linux.bin.gz uImage
3146 The "mkimage" tool can also be used to create ramdisk images for use
3147 with U-Boot, either separated from the Linux kernel image, or
3148 combined into one file. "mkimage" encapsulates the images with a 64
3149 byte header containing information about target architecture,
3150 operating system, image type, compression method, entry points, time
3151 stamp, CRC32 checksums, etc.
3153 "mkimage" can be called in two ways: to verify existing images and
3154 print the header information, or to build new images.
3156 In the first form (with "-l" option) mkimage lists the information
3157 contained in the header of an existing U-Boot image; this includes
3158 checksum verification:
3160 tools/mkimage -l image
3161 -l ==> list image header information
3163 The second form (with "-d" option) is used to build a U-Boot image
3164 from a "data file" which is used as image payload:
3166 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3167 -n name -d data_file image
3168 -A ==> set architecture to 'arch'
3169 -O ==> set operating system to 'os'
3170 -T ==> set image type to 'type'
3171 -C ==> set compression type 'comp'
3172 -a ==> set load address to 'addr' (hex)
3173 -e ==> set entry point to 'ep' (hex)
3174 -n ==> set image name to 'name'
3175 -d ==> use image data from 'datafile'
3177 Right now, all Linux kernels for PowerPC systems use the same load
3178 address (0x00000000), but the entry point address depends on the
3181 - 2.2.x kernels have the entry point at 0x0000000C,
3182 - 2.3.x and later kernels have the entry point at 0x00000000.
3184 So a typical call to build a U-Boot image would read:
3186 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3187 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3188 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3189 > examples/uImage.TQM850L
3190 Image Name: 2.4.4 kernel for TQM850L
3191 Created: Wed Jul 19 02:34:59 2000
3192 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3193 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3194 Load Address: 0x00000000
3195 Entry Point: 0x00000000
3197 To verify the contents of the image (or check for corruption):
3199 -> tools/mkimage -l examples/uImage.TQM850L
3200 Image Name: 2.4.4 kernel for TQM850L
3201 Created: Wed Jul 19 02:34:59 2000
3202 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3203 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3204 Load Address: 0x00000000
3205 Entry Point: 0x00000000
3207 NOTE: for embedded systems where boot time is critical you can trade
3208 speed for memory and install an UNCOMPRESSED image instead: this
3209 needs more space in Flash, but boots much faster since it does not
3210 need to be uncompressed:
3212 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3213 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3214 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3215 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3216 > examples/uImage.TQM850L-uncompressed
3217 Image Name: 2.4.4 kernel for TQM850L
3218 Created: Wed Jul 19 02:34:59 2000
3219 Image Type: PowerPC Linux Kernel Image (uncompressed)
3220 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3221 Load Address: 0x00000000
3222 Entry Point: 0x00000000
3225 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3226 when your kernel is intended to use an initial ramdisk:
3228 -> tools/mkimage -n 'Simple Ramdisk Image' \
3229 > -A ppc -O linux -T ramdisk -C gzip \
3230 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3231 Image Name: Simple Ramdisk Image
3232 Created: Wed Jan 12 14:01:50 2000
3233 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3234 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3235 Load Address: 0x00000000
3236 Entry Point: 0x00000000
3239 Installing a Linux Image:
3240 -------------------------
3242 To downloading a U-Boot image over the serial (console) interface,
3243 you must convert the image to S-Record format:
3245 objcopy -I binary -O srec examples/image examples/image.srec
3247 The 'objcopy' does not understand the information in the U-Boot
3248 image header, so the resulting S-Record file will be relative to
3249 address 0x00000000. To load it to a given address, you need to
3250 specify the target address as 'offset' parameter with the 'loads'
3253 Example: install the image to address 0x40100000 (which on the
3254 TQM8xxL is in the first Flash bank):
3256 => erase 40100000 401FFFFF
3262 ## Ready for S-Record download ...
3263 ~>examples/image.srec
3264 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3266 15989 15990 15991 15992
3267 [file transfer complete]
3269 ## Start Addr = 0x00000000
3272 You can check the success of the download using the 'iminfo' command;
3273 this includes a checksum verification so you can be sure no data
3274 corruption happened:
3278 ## Checking Image at 40100000 ...
3279 Image Name: 2.2.13 for initrd on TQM850L
3280 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3281 Data Size: 335725 Bytes = 327 kB = 0 MB
3282 Load Address: 00000000
3283 Entry Point: 0000000c
3284 Verifying Checksum ... OK
3290 The "bootm" command is used to boot an application that is stored in
3291 memory (RAM or Flash). In case of a Linux kernel image, the contents
3292 of the "bootargs" environment variable is passed to the kernel as
3293 parameters. You can check and modify this variable using the
3294 "printenv" and "setenv" commands:
3297 => printenv bootargs
3298 bootargs=root=/dev/ram
3300 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3302 => printenv bootargs
3303 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3306 ## Booting Linux kernel at 40020000 ...
3307 Image Name: 2.2.13 for NFS on TQM850L
3308 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3309 Data Size: 381681 Bytes = 372 kB = 0 MB
3310 Load Address: 00000000
3311 Entry Point: 0000000c
3312 Verifying Checksum ... OK
3313 Uncompressing Kernel Image ... OK
3314 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
3315 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3316 time_init: decrementer frequency = 187500000/60
3317 Calibrating delay loop... 49.77 BogoMIPS
3318 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3321 If you want to boot a Linux kernel with initial ram disk, you pass
3322 the memory addresses of both the kernel and the initrd image (PPBCOOT
3323 format!) to the "bootm" command:
3325 => imi 40100000 40200000
3327 ## Checking Image at 40100000 ...
3328 Image Name: 2.2.13 for initrd on TQM850L
3329 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3330 Data Size: 335725 Bytes = 327 kB = 0 MB
3331 Load Address: 00000000
3332 Entry Point: 0000000c
3333 Verifying Checksum ... OK
3335 ## Checking Image at 40200000 ...
3336 Image Name: Simple Ramdisk Image
3337 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3338 Data Size: 566530 Bytes = 553 kB = 0 MB
3339 Load Address: 00000000
3340 Entry Point: 00000000
3341 Verifying Checksum ... OK
3343 => bootm 40100000 40200000
3344 ## Booting Linux kernel at 40100000 ...
3345 Image Name: 2.2.13 for initrd on TQM850L
3346 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3347 Data Size: 335725 Bytes = 327 kB = 0 MB
3348 Load Address: 00000000
3349 Entry Point: 0000000c
3350 Verifying Checksum ... OK
3351 Uncompressing Kernel Image ... OK
3352 ## Loading RAMDisk Image at 40200000 ...
3353 Image Name: Simple Ramdisk Image
3354 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3355 Data Size: 566530 Bytes = 553 kB = 0 MB
3356 Load Address: 00000000
3357 Entry Point: 00000000
3358 Verifying Checksum ... OK
3359 Loading Ramdisk ... OK
3360 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
3361 Boot arguments: root=/dev/ram
3362 time_init: decrementer frequency = 187500000/60
3363 Calibrating delay loop... 49.77 BogoMIPS
3365 RAMDISK: Compressed image found at block 0
3366 VFS: Mounted root (ext2 filesystem).
3370 Boot Linux and pass a flat device tree:
3373 First, U-Boot must be compiled with the appropriate defines. See the section
3374 titled "Linux Kernel Interface" above for a more in depth explanation. The
3375 following is an example of how to start a kernel and pass an updated
3381 oft=oftrees/mpc8540ads.dtb
3382 => tftp $oftaddr $oft
3383 Speed: 1000, full duplex
3385 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3386 Filename 'oftrees/mpc8540ads.dtb'.
3387 Load address: 0x300000
3390 Bytes transferred = 4106 (100a hex)
3391 => tftp $loadaddr $bootfile
3392 Speed: 1000, full duplex
3394 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3396 Load address: 0x200000
3397 Loading:############
3399 Bytes transferred = 1029407 (fb51f hex)
3404 => bootm $loadaddr - $oftaddr
3405 ## Booting image at 00200000 ...
3406 Image Name: Linux-2.6.17-dirty
3407 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3408 Data Size: 1029343 Bytes = 1005.2 kB
3409 Load Address: 00000000
3410 Entry Point: 00000000
3411 Verifying Checksum ... OK
3412 Uncompressing Kernel Image ... OK
3413 Booting using flat device tree at 0x300000
3414 Using MPC85xx ADS machine description
3415 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3419 More About U-Boot Image Types:
3420 ------------------------------
3422 U-Boot supports the following image types:
3424 "Standalone Programs" are directly runnable in the environment
3425 provided by U-Boot; it is expected that (if they behave
3426 well) you can continue to work in U-Boot after return from
3427 the Standalone Program.
3428 "OS Kernel Images" are usually images of some Embedded OS which
3429 will take over control completely. Usually these programs
3430 will install their own set of exception handlers, device
3431 drivers, set up the MMU, etc. - this means, that you cannot
3432 expect to re-enter U-Boot except by resetting the CPU.
3433 "RAMDisk Images" are more or less just data blocks, and their
3434 parameters (address, size) are passed to an OS kernel that is
3436 "Multi-File Images" contain several images, typically an OS
3437 (Linux) kernel image and one or more data images like
3438 RAMDisks. This construct is useful for instance when you want
3439 to boot over the network using BOOTP etc., where the boot
3440 server provides just a single image file, but you want to get
3441 for instance an OS kernel and a RAMDisk image.
3443 "Multi-File Images" start with a list of image sizes, each
3444 image size (in bytes) specified by an "uint32_t" in network
3445 byte order. This list is terminated by an "(uint32_t)0".
3446 Immediately after the terminating 0 follow the images, one by
3447 one, all aligned on "uint32_t" boundaries (size rounded up to
3448 a multiple of 4 bytes).
3450 "Firmware Images" are binary images containing firmware (like
3451 U-Boot or FPGA images) which usually will be programmed to
3454 "Script files" are command sequences that will be executed by
3455 U-Boot's command interpreter; this feature is especially
3456 useful when you configure U-Boot to use a real shell (hush)
3457 as command interpreter.
3463 One of the features of U-Boot is that you can dynamically load and
3464 run "standalone" applications, which can use some resources of
3465 U-Boot like console I/O functions or interrupt services.
3467 Two simple examples are included with the sources:
3472 'examples/hello_world.c' contains a small "Hello World" Demo
3473 application; it is automatically compiled when you build U-Boot.
3474 It's configured to run at address 0x00040004, so you can play with it
3478 ## Ready for S-Record download ...
3479 ~>examples/hello_world.srec
3480 1 2 3 4 5 6 7 8 9 10 11 ...
3481 [file transfer complete]
3483 ## Start Addr = 0x00040004
3485 => go 40004 Hello World! This is a test.
3486 ## Starting application at 0x00040004 ...
3497 Hit any key to exit ...
3499 ## Application terminated, rc = 0x0
3501 Another example, which demonstrates how to register a CPM interrupt
3502 handler with the U-Boot code, can be found in 'examples/timer.c'.
3503 Here, a CPM timer is set up to generate an interrupt every second.
3504 The interrupt service routine is trivial, just printing a '.'
3505 character, but this is just a demo program. The application can be
3506 controlled by the following keys:
3508 ? - print current values og the CPM Timer registers
3509 b - enable interrupts and start timer
3510 e - stop timer and disable interrupts
3511 q - quit application
3514 ## Ready for S-Record download ...
3515 ~>examples/timer.srec
3516 1 2 3 4 5 6 7 8 9 10 11 ...
3517 [file transfer complete]
3519 ## Start Addr = 0x00040004
3522 ## Starting application at 0x00040004 ...
3525 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3528 [q, b, e, ?] Set interval 1000000 us
3531 [q, b, e, ?] ........
3532 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3535 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3538 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3541 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3543 [q, b, e, ?] ...Stopping timer
3545 [q, b, e, ?] ## Application terminated, rc = 0x0
3551 Over time, many people have reported problems when trying to use the
3552 "minicom" terminal emulation program for serial download. I (wd)
3553 consider minicom to be broken, and recommend not to use it. Under
3554 Unix, I recommend to use C-Kermit for general purpose use (and
3555 especially for kermit binary protocol download ("loadb" command), and
3556 use "cu" for S-Record download ("loads" command).
3558 Nevertheless, if you absolutely want to use it try adding this
3559 configuration to your "File transfer protocols" section:
3561 Name Program Name U/D FullScr IO-Red. Multi
3562 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3563 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3569 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3570 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3572 Building requires a cross environment; it is known to work on
3573 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3574 need gmake since the Makefiles are not compatible with BSD make).
3575 Note that the cross-powerpc package does not install include files;
3576 attempting to build U-Boot will fail because <machine/ansi.h> is
3577 missing. This file has to be installed and patched manually:
3579 # cd /usr/pkg/cross/powerpc-netbsd/include
3581 # ln -s powerpc machine
3582 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3583 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3585 Native builds *don't* work due to incompatibilities between native
3586 and U-Boot include files.
3588 Booting assumes that (the first part of) the image booted is a
3589 stage-2 loader which in turn loads and then invokes the kernel
3590 proper. Loader sources will eventually appear in the NetBSD source
3591 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3592 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3595 Implementation Internals:
3596 =========================
3598 The following is not intended to be a complete description of every
3599 implementation detail. However, it should help to understand the
3600 inner workings of U-Boot and make it easier to port it to custom
3604 Initial Stack, Global Data:
3605 ---------------------------
3607 The implementation of U-Boot is complicated by the fact that U-Boot
3608 starts running out of ROM (flash memory), usually without access to
3609 system RAM (because the memory controller is not initialized yet).
3610 This means that we don't have writable Data or BSS segments, and BSS
3611 is not initialized as zero. To be able to get a C environment working
3612 at all, we have to allocate at least a minimal stack. Implementation
3613 options for this are defined and restricted by the CPU used: Some CPU
3614 models provide on-chip memory (like the IMMR area on MPC8xx and
3615 MPC826x processors), on others (parts of) the data cache can be
3616 locked as (mis-) used as memory, etc.
3618 Chris Hallinan posted a good summary of these issues to the
3619 u-boot-users mailing list:
3621 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3622 From: "Chris Hallinan" <clh@net1plus.com>
3623 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3626 Correct me if I'm wrong, folks, but the way I understand it
3627 is this: Using DCACHE as initial RAM for Stack, etc, does not
3628 require any physical RAM backing up the cache. The cleverness
3629 is that the cache is being used as a temporary supply of
3630 necessary storage before the SDRAM controller is setup. It's
3631 beyond the scope of this list to expain the details, but you
3632 can see how this works by studying the cache architecture and
3633 operation in the architecture and processor-specific manuals.
3635 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3636 is another option for the system designer to use as an
3637 initial stack/ram area prior to SDRAM being available. Either
3638 option should work for you. Using CS 4 should be fine if your
3639 board designers haven't used it for something that would
3640 cause you grief during the initial boot! It is frequently not
3643 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3644 with your processor/board/system design. The default value
3645 you will find in any recent u-boot distribution in
3646 walnut.h should work for you. I'd set it to a value larger
3647 than your SDRAM module. If you have a 64MB SDRAM module, set
3648 it above 400_0000. Just make sure your board has no resources
3649 that are supposed to respond to that address! That code in
3650 start.S has been around a while and should work as is when
3651 you get the config right.
3656 It is essential to remember this, since it has some impact on the C
3657 code for the initialization procedures:
3659 * Initialized global data (data segment) is read-only. Do not attempt
3662 * Do not use any unitialized global data (or implicitely initialized
3663 as zero data - BSS segment) at all - this is undefined, initiali-
3664 zation is performed later (when relocating to RAM).
3666 * Stack space is very limited. Avoid big data buffers or things like
3669 Having only the stack as writable memory limits means we cannot use
3670 normal global data to share information beween the code. But it
3671 turned out that the implementation of U-Boot can be greatly
3672 simplified by making a global data structure (gd_t) available to all
3673 functions. We could pass a pointer to this data as argument to _all_
3674 functions, but this would bloat the code. Instead we use a feature of
3675 the GCC compiler (Global Register Variables) to share the data: we
3676 place a pointer (gd) to the global data into a register which we
3677 reserve for this purpose.
3679 When choosing a register for such a purpose we are restricted by the
3680 relevant (E)ABI specifications for the current architecture, and by
3681 GCC's implementation.
3683 For PowerPC, the following registers have specific use:
3685 R2: reserved for system use
3686 R3-R4: parameter passing and return values
3687 R5-R10: parameter passing
3688 R13: small data area pointer
3692 (U-Boot also uses R14 as internal GOT pointer.)
3694 ==> U-Boot will use R2 to hold a pointer to the global data
3696 Note: on PPC, we could use a static initializer (since the
3697 address of the global data structure is known at compile time),
3698 but it turned out that reserving a register results in somewhat
3699 smaller code - although the code savings are not that big (on
3700 average for all boards 752 bytes for the whole U-Boot image,
3701 624 text + 127 data).
3703 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3704 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3706 ==> U-Boot will use P5 to hold a pointer to the global data
3708 On ARM, the following registers are used:
3710 R0: function argument word/integer result
3711 R1-R3: function argument word
3713 R10: stack limit (used only if stack checking if enabled)
3714 R11: argument (frame) pointer
3715 R12: temporary workspace
3718 R15: program counter
3720 ==> U-Boot will use R8 to hold a pointer to the global data
3722 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3723 or current versions of GCC may "optimize" the code too much.
3728 U-Boot runs in system state and uses physical addresses, i.e. the
3729 MMU is not used either for address mapping nor for memory protection.
3731 The available memory is mapped to fixed addresses using the memory
3732 controller. In this process, a contiguous block is formed for each
3733 memory type (Flash, SDRAM, SRAM), even when it consists of several
3734 physical memory banks.
3736 U-Boot is installed in the first 128 kB of the first Flash bank (on
3737 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3738 booting and sizing and initializing DRAM, the code relocates itself
3739 to the upper end of DRAM. Immediately below the U-Boot code some
3740 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3741 configuration setting]. Below that, a structure with global Board
3742 Info data is placed, followed by the stack (growing downward).
3744 Additionally, some exception handler code is copied to the low 8 kB
3745 of DRAM (0x00000000 ... 0x00001FFF).
3747 So a typical memory configuration with 16 MB of DRAM could look like
3750 0x0000 0000 Exception Vector code
3753 0x0000 2000 Free for Application Use
3759 0x00FB FF20 Monitor Stack (Growing downward)
3760 0x00FB FFAC Board Info Data and permanent copy of global data
3761 0x00FC 0000 Malloc Arena
3764 0x00FE 0000 RAM Copy of Monitor Code
3765 ... eventually: LCD or video framebuffer
3766 ... eventually: pRAM (Protected RAM - unchanged by reset)
3767 0x00FF FFFF [End of RAM]
3770 System Initialization:
3771 ----------------------
3773 In the reset configuration, U-Boot starts at the reset entry point
3774 (on most PowerPC systens at address 0x00000100). Because of the reset
3775 configuration for CS0# this is a mirror of the onboard Flash memory.
3776 To be able to re-map memory U-Boot then jumps to its link address.
3777 To be able to implement the initialization code in C, a (small!)
3778 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3779 which provide such a feature like MPC8xx or MPC8260), or in a locked
3780 part of the data cache. After that, U-Boot initializes the CPU core,
3781 the caches and the SIU.
3783 Next, all (potentially) available memory banks are mapped using a
3784 preliminary mapping. For example, we put them on 512 MB boundaries
3785 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3786 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3787 programmed for SDRAM access. Using the temporary configuration, a
3788 simple memory test is run that determines the size of the SDRAM
3791 When there is more than one SDRAM bank, and the banks are of
3792 different size, the largest is mapped first. For equal size, the first
3793 bank (CS2#) is mapped first. The first mapping is always for address
3794 0x00000000, with any additional banks following immediately to create
3795 contiguous memory starting from 0.
3797 Then, the monitor installs itself at the upper end of the SDRAM area
3798 and allocates memory for use by malloc() and for the global Board
3799 Info data; also, the exception vector code is copied to the low RAM
3800 pages, and the final stack is set up.
3802 Only after this relocation will you have a "normal" C environment;
3803 until that you are restricted in several ways, mostly because you are
3804 running from ROM, and because the code will have to be relocated to a
3808 U-Boot Porting Guide:
3809 ----------------------
3811 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3815 int main (int argc, char *argv[])
3817 sighandler_t no_more_time;
3819 signal (SIGALRM, no_more_time);
3820 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3822 if (available_money > available_manpower) {
3823 pay consultant to port U-Boot;
3827 Download latest U-Boot source;
3829 Subscribe to u-boot-users mailing list;
3832 email ("Hi, I am new to U-Boot, how do I get started?");
3836 Read the README file in the top level directory;
3837 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3838 Read the source, Luke;
3841 if (available_money > toLocalCurrency ($2500)) {
3844 Add a lot of aggravation and time;
3847 Create your own board support subdirectory;
3849 Create your own board config file;
3853 Add / modify source code;
3857 email ("Hi, I am having problems...");
3859 Send patch file to Wolfgang;
3864 void no_more_time (int sig)
3873 All contributions to U-Boot should conform to the Linux kernel
3874 coding style; see the file "Documentation/CodingStyle" and the script
3875 "scripts/Lindent" in your Linux kernel source directory. In sources
3876 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3877 spaces before parameters to function calls) is actually used.
3879 Source files originating from a different project (for example the
3880 MTD subsystem) are generally exempt from these guidelines and are not
3881 reformated to ease subsequent migration to newer versions of those
3884 Please note that U-Boot is implemented in C (and to some small parts in
3885 Assembler); no C++ is used, so please do not use C++ style comments (//)
3888 Please also stick to the following formatting rules:
3889 - remove any trailing white space
3890 - use TAB characters for indentation, not spaces
3891 - make sure NOT to use DOS '\r\n' line feeds
3892 - do not add more than 2 empty lines to source files
3893 - do not add trailing empty lines to source files
3895 Submissions which do not conform to the standards may be returned
3896 with a request to reformat the changes.
3902 Since the number of patches for U-Boot is growing, we need to
3903 establish some rules. Submissions which do not conform to these rules
3904 may be rejected, even when they contain important and valuable stuff.
3906 Patches shall be sent to the u-boot-users mailing list.
3908 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3910 When you send a patch, please include the following information with
3913 * For bug fixes: a description of the bug and how your patch fixes
3914 this bug. Please try to include a way of demonstrating that the
3915 patch actually fixes something.
3917 * For new features: a description of the feature and your
3920 * A CHANGELOG entry as plaintext (separate from the patch)
3922 * For major contributions, your entry to the CREDITS file
3924 * When you add support for a new board, don't forget to add this
3925 board to the MAKEALL script, too.
3927 * If your patch adds new configuration options, don't forget to
3928 document these in the README file.
3930 * The patch itself. If you are using git (which is *strongly*
3931 recommended) you can easily generate the patch using the
3932 "git-format-patch". If you then use "git-send-email" to send it to
3933 the U-Boot mailing list, you will avoid most of the common problems
3934 with some other mail clients.
3936 If you cannot use git, use "diff -purN OLD NEW". If your version of
3937 diff does not support these options, then get the latest version of
3940 The current directory when running this command shall be the parent
3941 directory of the U-Boot source tree (i. e. please make sure that
3942 your patch includes sufficient directory information for the
3945 We prefer patches as plain text. MIME attachments are discouraged,
3946 and compressed attachments must not be used.
3948 * If one logical set of modifications affects or creates several
3949 files, all these changes shall be submitted in a SINGLE patch file.
3951 * Changesets that contain different, unrelated modifications shall be
3952 submitted as SEPARATE patches, one patch per changeset.
3957 * Before sending the patch, run the MAKEALL script on your patched
3958 source tree and make sure that no errors or warnings are reported
3959 for any of the boards.
3961 * Keep your modifications to the necessary minimum: A patch
3962 containing several unrelated changes or arbitrary reformats will be
3963 returned with a request to re-formatting / split it.
3965 * If you modify existing code, make sure that your new code does not
3966 add to the memory footprint of the code ;-) Small is beautiful!
3967 When adding new features, these should compile conditionally only
3968 (using #ifdef), and the resulting code with the new feature
3969 disabled must not need more memory than the old code without your
3972 * Remember that there is a size limit of 40 kB per message on the
3973 u-boot-users mailing list. Bigger patches will be moderated. If
3974 they are reasonable and not bigger than 100 kB, they will be
3975 acknowledged. Even bigger patches should be avoided.
projects / u-boot / blob