2 # (C) Copyright 2000 - 2005
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.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
140 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
141 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
142 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
143 - mips Files specific to MIPS CPUs
144 - mpc5xx Files specific to Freescale MPC5xx CPUs
145 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
146 - mpc8xx Files specific to Freescale MPC8xx CPUs
147 - mpc8220 Files specific to Freescale MPC8220 CPUs
148 - mpc824x Files specific to Freescale MPC824x CPUs
149 - mpc8260 Files specific to Freescale MPC8260 CPUs
150 - mpc85xx Files specific to Freescale MPC85xx CPUs
151 - nios Files specific to Altera NIOS CPUs
152 - nios2 Files specific to Altera Nios-II CPUs
153 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
154 - pxa Files specific to Intel XScale PXA CPUs
155 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
156 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
157 - disk Code for disk drive partition handling
158 - doc Documentation (don't expect too much)
159 - drivers Commonly used device drivers
160 - dtt Digital Thermometer and Thermostat drivers
161 - examples Example code for standalone applications, etc.
162 - include Header Files
163 - lib_arm Files generic to ARM architecture
164 - lib_avr32 Files generic to AVR32 architecture
165 - lib_generic Files generic to all architectures
166 - lib_i386 Files generic to i386 architecture
167 - lib_m68k Files generic to m68k architecture
168 - lib_mips Files generic to MIPS architecture
169 - lib_nios Files generic to NIOS architecture
170 - lib_ppc Files generic to PowerPC architecture
171 - libfdt Library files to support flattened device trees
172 - net Networking code
173 - post Power On Self Test
174 - rtc Real Time Clock drivers
175 - tools Tools to build S-Record or U-Boot images, etc.
177 Software Configuration:
178 =======================
180 Configuration is usually done using C preprocessor defines; the
181 rationale behind that is to avoid dead code whenever possible.
183 There are two classes of configuration variables:
185 * Configuration _OPTIONS_:
186 These are selectable by the user and have names beginning with
189 * Configuration _SETTINGS_:
190 These depend on the hardware etc. and should not be meddled with if
191 you don't know what you're doing; they have names beginning with
194 Later we will add a configuration tool - probably similar to or even
195 identical to what's used for the Linux kernel. Right now, we have to
196 do the configuration by hand, which means creating some symbolic
197 links and editing some configuration files. We use the TQM8xxL boards
201 Selection of Processor Architecture and Board Type:
202 ---------------------------------------------------
204 For all supported boards there are ready-to-use default
205 configurations available; just type "make <board_name>_config".
207 Example: For a TQM823L module type:
212 For the Cogent platform, you need to specify the cpu type as well;
213 e.g. "make cogent_mpc8xx_config". And also configure the cogent
214 directory according to the instructions in cogent/README.
217 Configuration Options:
218 ----------------------
220 Configuration depends on the combination of board and CPU type; all
221 such information is kept in a configuration file
222 "include/configs/<board_name>.h".
224 Example: For a TQM823L module, all configuration settings are in
225 "include/configs/TQM823L.h".
228 Many of the options are named exactly as the corresponding Linux
229 kernel configuration options. The intention is to make it easier to
230 build a config tool - later.
233 The following options need to be configured:
235 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
237 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
239 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
240 Define exactly one, e.g. CONFIG_ATSTK1002
242 - CPU Module Type: (if CONFIG_COGENT is defined)
243 Define exactly one of
245 --- FIXME --- not tested yet:
246 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
247 CONFIG_CMA287_23, CONFIG_CMA287_50
249 - Motherboard Type: (if CONFIG_COGENT is defined)
250 Define exactly one of
251 CONFIG_CMA101, CONFIG_CMA102
253 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
254 Define one or more of
257 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
258 Define one or more of
259 CONFIG_LCD_HEARTBEAT - update a character position on
260 the lcd display every second with
263 - Board flavour: (if CONFIG_MPC8260ADS is defined)
266 CFG_8260ADS - original MPC8260ADS
267 CFG_8266ADS - MPC8266ADS
268 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
269 CFG_8272ADS - MPC8272ADS
271 - MPC824X Family Member (if CONFIG_MPC824X is defined)
272 Define exactly one of
273 CONFIG_MPC8240, CONFIG_MPC8245
275 - 8xx CPU Options: (if using an MPC8xx cpu)
276 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
277 get_gclk_freq() cannot work
278 e.g. if there is no 32KHz
279 reference PIT/RTC clock
280 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
283 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
286 CONFIG_8xx_CPUCLK_DEFAULT
287 See doc/README.MPC866
291 Define this to measure the actual CPU clock instead
292 of relying on the correctness of the configured
293 values. Mostly useful for board bringup to make sure
294 the PLL is locked at the intended frequency. Note
295 that this requires a (stable) reference clock (32 kHz
296 RTC clock or CFG_8XX_XIN)
298 - Intel Monahans options:
299 CFG_MONAHANS_RUN_MODE_OSC_RATIO
301 Defines the Monahans run mode to oscillator
302 ratio. Valid values are 8, 16, 24, 31. The core
303 frequency is this value multiplied by 13 MHz.
305 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
307 Defines the Monahans turbo mode to oscillator
308 ratio. Valid values are 1 (default if undefined) and
309 2. The core frequency as calculated above is multiplied
312 - Linux Kernel Interface:
315 U-Boot stores all clock information in Hz
316 internally. For binary compatibility with older Linux
317 kernels (which expect the clocks passed in the
318 bd_info data to be in MHz) the environment variable
319 "clocks_in_mhz" can be defined so that U-Boot
320 converts clock data to MHZ before passing it to the
322 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
323 "clocks_in_mhz=1" is automatically included in the
326 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
328 When transfering memsize parameter to linux, some versions
329 expect it to be in bytes, others in MB.
330 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
332 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
334 New kernel versions are expecting firmware settings to be
335 passed using flattened device trees (based on open firmware
339 * New libfdt-based support
340 * Adds the "fdt" command
341 * The bootm command automatically updates the fdt
344 * Deprecated, see CONFIG_OF_LIBFDT
345 * Original ft_build.c-based support
346 * Automatically modifies the dft as part of the bootm command
347 * The environment variable "disable_of", when set,
348 disables this functionality.
350 OF_CPU - The proper name of the cpus node.
351 OF_SOC - The proper name of the soc node.
352 OF_TBCLK - The timebase frequency.
353 OF_STDOUT_PATH - The path to the console device
355 boards with QUICC Engines require OF_QE to set UCC mac addresses
359 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
360 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
361 will have a copy of the bd_t. Space should be
362 pre-allocated in the dts for the bd_t.
364 CONFIG_OF_HAS_UBOOT_ENV
366 * CONFIG_OF_LIBFDT - enables the "fdt env" command
367 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
368 will have a copy of u-boot's environment variables
370 CONFIG_OF_BOARD_SETUP
372 Board code has addition modification that it wants to make
373 to the flat device tree before handing it off to the kernel
377 This define fills in the correct boot cpu in the boot
378 param header, the default value is zero if undefined.
383 Define this if you want support for Amba PrimeCell PL010 UARTs.
387 Define this if you want support for Amba PrimeCell PL011 UARTs.
391 If you have Amba PrimeCell PL011 UARTs, set this variable to
392 the clock speed of the UARTs.
396 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
397 define this to a list of base addresses for each (supported)
398 port. See e.g. include/configs/versatile.h
402 Depending on board, define exactly one serial port
403 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
404 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
405 console by defining CONFIG_8xx_CONS_NONE
407 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
408 port routines must be defined elsewhere
409 (i.e. serial_init(), serial_getc(), ...)
412 Enables console device for a color framebuffer. Needs following
413 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
414 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
416 VIDEO_HW_RECTFILL graphic chip supports
419 VIDEO_HW_BITBLT graphic chip supports
420 bit-blit (cf. smiLynxEM)
421 VIDEO_VISIBLE_COLS visible pixel columns
423 VIDEO_VISIBLE_ROWS visible pixel rows
424 VIDEO_PIXEL_SIZE bytes per pixel
425 VIDEO_DATA_FORMAT graphic data format
426 (0-5, cf. cfb_console.c)
427 VIDEO_FB_ADRS framebuffer address
428 VIDEO_KBD_INIT_FCT keyboard int fct
429 (i.e. i8042_kbd_init())
430 VIDEO_TSTC_FCT test char fct
432 VIDEO_GETC_FCT get char fct
434 CONFIG_CONSOLE_CURSOR cursor drawing on/off
435 (requires blink timer
437 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
438 CONFIG_CONSOLE_TIME display time/date info in
440 (requires CONFIG_CMD_DATE)
441 CONFIG_VIDEO_LOGO display Linux logo in
443 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
444 linux_logo.h for logo.
445 Requires CONFIG_VIDEO_LOGO
446 CONFIG_CONSOLE_EXTRA_INFO
447 addional board info beside
450 When CONFIG_CFB_CONSOLE is defined, video console is
451 default i/o. Serial console can be forced with
452 environment 'console=serial'.
454 When CONFIG_SILENT_CONSOLE is defined, all console
455 messages (by U-Boot and Linux!) can be silenced with
456 the "silent" environment variable. See
457 doc/README.silent for more information.
460 CONFIG_BAUDRATE - in bps
461 Select one of the baudrates listed in
462 CFG_BAUDRATE_TABLE, see below.
463 CFG_BRGCLK_PRESCALE, baudrate prescale
465 - Interrupt driven serial port input:
466 CONFIG_SERIAL_SOFTWARE_FIFO
469 Use an interrupt handler for receiving data on the
470 serial port. It also enables using hardware handshake
471 (RTS/CTS) and UART's built-in FIFO. Set the number of
472 bytes the interrupt driven input buffer should have.
474 Leave undefined to disable this feature, including
475 disable the buffer and hardware handshake.
477 - Console UART Number:
481 If defined internal UART1 (and not UART0) is used
482 as default U-Boot console.
484 - Boot Delay: CONFIG_BOOTDELAY - in seconds
485 Delay before automatically booting the default image;
486 set to -1 to disable autoboot.
488 See doc/README.autoboot for these options that
489 work with CONFIG_BOOTDELAY. None are required.
490 CONFIG_BOOT_RETRY_TIME
491 CONFIG_BOOT_RETRY_MIN
492 CONFIG_AUTOBOOT_KEYED
493 CONFIG_AUTOBOOT_PROMPT
494 CONFIG_AUTOBOOT_DELAY_STR
495 CONFIG_AUTOBOOT_STOP_STR
496 CONFIG_AUTOBOOT_DELAY_STR2
497 CONFIG_AUTOBOOT_STOP_STR2
498 CONFIG_ZERO_BOOTDELAY_CHECK
499 CONFIG_RESET_TO_RETRY
503 Only needed when CONFIG_BOOTDELAY is enabled;
504 define a command string that is automatically executed
505 when no character is read on the console interface
506 within "Boot Delay" after reset.
509 This can be used to pass arguments to the bootm
510 command. The value of CONFIG_BOOTARGS goes into the
511 environment value "bootargs".
513 CONFIG_RAMBOOT and CONFIG_NFSBOOT
514 The value of these goes into the environment as
515 "ramboot" and "nfsboot" respectively, and can be used
516 as a convenience, when switching between booting from
522 When this option is #defined, the existence of the
523 environment variable "preboot" will be checked
524 immediately before starting the CONFIG_BOOTDELAY
525 countdown and/or running the auto-boot command resp.
526 entering interactive mode.
528 This feature is especially useful when "preboot" is
529 automatically generated or modified. For an example
530 see the LWMON board specific code: here "preboot" is
531 modified when the user holds down a certain
532 combination of keys on the (special) keyboard when
535 - Serial Download Echo Mode:
537 If defined to 1, all characters received during a
538 serial download (using the "loads" command) are
539 echoed back. This might be needed by some terminal
540 emulations (like "cu"), but may as well just take
541 time on others. This setting #define's the initial
542 value of the "loads_echo" environment variable.
544 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
546 Select one of the baudrates listed in
547 CFG_BAUDRATE_TABLE, see below.
550 Monitor commands can be included or excluded
551 from the build by using the #include files
552 "config_cmd_all.h" and #undef'ing unwanted
553 commands, or using "config_cmd_default.h"
554 and augmenting with additional #define's
557 The default command configuration includes all commands
558 except those marked below with a "*".
560 CONFIG_CMD_ASKENV * ask for env variable
561 CONFIG_CMD_AUTOSCRIPT Autoscript Support
562 CONFIG_CMD_BDI bdinfo
563 CONFIG_CMD_BEDBUG * Include BedBug Debugger
564 CONFIG_CMD_BMP * BMP support
565 CONFIG_CMD_BSP * Board specific commands
566 CONFIG_CMD_BOOTD bootd
567 CONFIG_CMD_CACHE * icache, dcache
568 CONFIG_CMD_CONSOLE coninfo
569 CONFIG_CMD_DATE * support for RTC, date/time...
570 CONFIG_CMD_DHCP * DHCP support
571 CONFIG_CMD_DIAG * Diagnostics
572 CONFIG_CMD_DOC * Disk-On-Chip Support
573 CONFIG_CMD_DTT * Digital Therm and Thermostat
574 CONFIG_CMD_ECHO echo arguments
575 CONFIG_CMD_EEPROM * EEPROM read/write support
576 CONFIG_CMD_ELF * bootelf, bootvx
577 CONFIG_CMD_ENV saveenv
578 CONFIG_CMD_FDC * Floppy Disk Support
579 CONFIG_CMD_FAT * FAT partition support
580 CONFIG_CMD_FDOS * Dos diskette Support
581 CONFIG_CMD_FLASH flinfo, erase, protect
582 CONFIG_CMD_FPGA FPGA device initialization support
583 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
584 CONFIG_CMD_I2C * I2C serial bus support
585 CONFIG_CMD_IDE * IDE harddisk support
586 CONFIG_CMD_IMI iminfo
587 CONFIG_CMD_IMLS List all found images
588 CONFIG_CMD_IMMAP * IMMR dump support
589 CONFIG_CMD_IRQ * irqinfo
590 CONFIG_CMD_ITEST Integer/string test of 2 values
591 CONFIG_CMD_JFFS2 * JFFS2 Support
592 CONFIG_CMD_KGDB * kgdb
593 CONFIG_CMD_LOADB loadb
594 CONFIG_CMD_LOADS loads
595 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
597 CONFIG_CMD_MISC Misc functions like sleep etc
598 CONFIG_CMD_MMC * MMC memory mapped support
599 CONFIG_CMD_MII * MII utility commands
600 CONFIG_CMD_NAND * NAND support
601 CONFIG_CMD_NET bootp, tftpboot, rarpboot
602 CONFIG_CMD_PCI * pciinfo
603 CONFIG_CMD_PCMCIA * PCMCIA support
604 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
606 CONFIG_CMD_PORTIO * Port I/O
607 CONFIG_CMD_REGINFO * Register dump
608 CONFIG_CMD_RUN run command in env variable
609 CONFIG_CMD_SAVES * save S record dump
610 CONFIG_CMD_SCSI * SCSI Support
611 CONFIG_CMD_SDRAM * print SDRAM configuration information
612 (requires CONFIG_CMD_I2C)
613 CONFIG_CMD_SETGETDCR Support for DCR Register access
615 CONFIG_CMD_SPI * SPI serial bus support
616 CONFIG_CMD_USB * USB support
617 CONFIG_CMD_VFD * VFD support (TRAB)
618 CONFIG_CMD_BSP * Board SPecific functions
619 CONFIG_CMD_CDP * Cisco Discover Protocol support
620 CONFIG_CMD_FSL * Microblaze FSL support
623 EXAMPLE: If you want all functions except of network
624 support you can write:
626 #include "config_cmd_all.h"
627 #undef CONFIG_CMD_NET
630 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
632 Note: Don't enable the "icache" and "dcache" commands
633 (configuration option CONFIG_CMD_CACHE) unless you know
634 what you (and your U-Boot users) are doing. Data
635 cache cannot be enabled on systems like the 8xx or
636 8260 (where accesses to the IMMR region must be
637 uncached), and it cannot be disabled on all other
638 systems where we (mis-) use the data cache to hold an
639 initial stack and some data.
642 XXX - this list needs to get updated!
646 If this variable is defined, it enables watchdog
647 support. There must be support in the platform specific
648 code for a watchdog. For the 8xx and 8260 CPUs, the
649 SIU Watchdog feature is enabled in the SYPCR
653 CONFIG_VERSION_VARIABLE
654 If this variable is defined, an environment variable
655 named "ver" is created by U-Boot showing the U-Boot
656 version as printed by the "version" command.
657 This variable is readonly.
661 When CONFIG_CMD_DATE is selected, the type of the RTC
662 has to be selected, too. Define exactly one of the
665 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
666 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
667 CONFIG_RTC_MC146818 - use MC146818 RTC
668 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
669 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
670 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
671 CONFIG_RTC_DS164x - use Dallas DS164x RTC
672 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
674 Note that if the RTC uses I2C, then the I2C interface
675 must also be configured. See I2C Support, below.
679 When CONFIG_TIMESTAMP is selected, the timestamp
680 (date and time) of an image is printed by image
681 commands like bootm or iminfo. This option is
682 automatically enabled when you select CONFIG_CMD_DATE .
685 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
686 and/or CONFIG_ISO_PARTITION
688 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
689 CONFIG_CMD_SCSI) you must configure support for at least
690 one partition type as well.
693 CONFIG_IDE_RESET_ROUTINE - this is defined in several
694 board configurations files but used nowhere!
696 CONFIG_IDE_RESET - is this is defined, IDE Reset will
697 be performed by calling the function
698 ide_set_reset(int reset)
699 which has to be defined in a board specific file
704 Set this to enable ATAPI support.
709 Set this to enable support for disks larger than 137GB
710 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
711 Whithout these , LBA48 support uses 32bit variables and will 'only'
712 support disks up to 2.1TB.
715 When enabled, makes the IDE subsystem use 64bit sector addresses.
719 At the moment only there is only support for the
720 SYM53C8XX SCSI controller; define
721 CONFIG_SCSI_SYM53C8XX to enable it.
723 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
724 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
725 CFG_SCSI_MAX_LUN] can be adjusted to define the
726 maximum numbers of LUNs, SCSI ID's and target
728 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
730 - NETWORK Support (PCI):
732 Support for Intel 8254x gigabit chips.
735 Support for Intel 82557/82559/82559ER chips.
736 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
737 write routine for first time initialisation.
740 Support for Digital 2114x chips.
741 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
742 modem chip initialisation (KS8761/QS6611).
745 Support for National dp83815 chips.
748 Support for National dp8382[01] gigabit chips.
750 - NETWORK Support (other):
752 CONFIG_DRIVER_LAN91C96
753 Support for SMSC's LAN91C96 chips.
756 Define this to hold the physical address
757 of the LAN91C96's I/O space
759 CONFIG_LAN91C96_USE_32_BIT
760 Define this to enable 32 bit addressing
762 CONFIG_DRIVER_SMC91111
763 Support for SMSC's LAN91C111 chip
766 Define this to hold the physical address
767 of the device (I/O space)
769 CONFIG_SMC_USE_32_BIT
770 Define this if data bus is 32 bits
772 CONFIG_SMC_USE_IOFUNCS
773 Define this to use i/o functions instead of macros
774 (some hardware wont work with macros)
777 At the moment only the UHCI host controller is
778 supported (PIP405, MIP405, MPC5200); define
779 CONFIG_USB_UHCI to enable it.
780 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
781 and define CONFIG_USB_STORAGE to enable the USB
784 Supported are USB Keyboards and USB Floppy drives
786 MPC5200 USB requires additional defines:
788 for 528 MHz Clock: 0x0001bbbb
790 for differential drivers: 0x00001000
791 for single ended drivers: 0x00005000
793 May be defined to allow interrupt polling
794 instead of using asynchronous interrupts
797 Define the below if you wish to use the USB console.
798 Once firmware is rebuilt from a serial console issue the
799 command "setenv stdin usbtty; setenv stdout usbtty" and
800 attach your usb cable. The Unix command "dmesg" should print
801 it has found a new device. The environment variable usbtty
802 can be set to gserial or cdc_acm to enable your device to
803 appear to a USB host as a Linux gserial device or a
804 Common Device Class Abstract Control Model serial device.
805 If you select usbtty = gserial you should be able to enumerate
807 # modprobe usbserial vendor=0xVendorID product=0xProductID
808 else if using cdc_acm, simply setting the environment
809 variable usbtty to be cdc_acm should suffice. The following
810 might be defined in YourBoardName.h
813 Define this to build a UDC device
816 Define this to have a tty type of device available to
817 talk to the UDC device
819 CFG_CONSOLE_IS_IN_ENV
820 Define this if you want stdin, stdout &/or stderr to
824 CFG_USB_EXTC_CLK 0xBLAH
825 Derive USB clock from external clock "blah"
826 - CFG_USB_EXTC_CLK 0x02
828 CFG_USB_BRG_CLK 0xBLAH
829 Derive USB clock from brgclk
830 - CFG_USB_BRG_CLK 0x04
832 If you have a USB-IF assigned VendorID then you may wish to
833 define your own vendor specific values either in BoardName.h
834 or directly in usbd_vendor_info.h. If you don't define
835 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
836 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
837 should pretend to be a Linux device to it's target host.
839 CONFIG_USBD_MANUFACTURER
840 Define this string as the name of your company for
841 - CONFIG_USBD_MANUFACTURER "my company"
843 CONFIG_USBD_PRODUCT_NAME
844 Define this string as the name of your product
845 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
848 Define this as your assigned Vendor ID from the USB
849 Implementors Forum. This *must* be a genuine Vendor ID
850 to avoid polluting the USB namespace.
851 - CONFIG_USBD_VENDORID 0xFFFF
853 CONFIG_USBD_PRODUCTID
854 Define this as the unique Product ID
856 - CONFIG_USBD_PRODUCTID 0xFFFF
860 The MMC controller on the Intel PXA is supported. To
861 enable this define CONFIG_MMC. The MMC can be
862 accessed from the boot prompt by mapping the device
863 to physical memory similar to flash. Command line is
864 enabled with CONFIG_CMD_MMC. The MMC driver also works with
865 the FAT fs. This is enabled with CONFIG_CMD_FAT.
867 - Journaling Flash filesystem support:
868 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
869 CONFIG_JFFS2_NAND_DEV
870 Define these for a default partition on a NAND device
872 CFG_JFFS2_FIRST_SECTOR,
873 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
874 Define these for a default partition on a NOR device
877 Define this to create an own partition. You have to provide a
878 function struct part_info* jffs2_part_info(int part_num)
880 If you define only one JFFS2 partition you may also want to
881 #define CFG_JFFS_SINGLE_PART 1
882 to disable the command chpart. This is the default when you
883 have not defined a custom partition
888 Define this to enable standard (PC-Style) keyboard
892 Standard PC keyboard driver with US (is default) and
893 GERMAN key layout (switch via environment 'keymap=de') support.
894 Export function i8042_kbd_init, i8042_tstc and i8042_getc
895 for cfb_console. Supports cursor blinking.
900 Define this to enable video support (for output to
905 Enable Chips & Technologies 69000 Video chip
907 CONFIG_VIDEO_SMI_LYNXEM
908 Enable Silicon Motion SMI 712/710/810 Video chip. The
909 video output is selected via environment 'videoout'
910 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
913 For the CT69000 and SMI_LYNXEM drivers, videomode is
914 selected via environment 'videomode'. Two diferent ways
916 - "videomode=num" 'num' is a standard LiLo mode numbers.
917 Following standard modes are supported (* is default):
919 Colors 640x480 800x600 1024x768 1152x864 1280x1024
920 -------------+---------------------------------------------
921 8 bits | 0x301* 0x303 0x305 0x161 0x307
922 15 bits | 0x310 0x313 0x316 0x162 0x319
923 16 bits | 0x311 0x314 0x317 0x163 0x31A
924 24 bits | 0x312 0x315 0x318 ? 0x31B
925 -------------+---------------------------------------------
926 (i.e. setenv videomode 317; saveenv; reset;)
928 - "videomode=bootargs" all the video parameters are parsed
929 from the bootargs. (See drivers/video/videomodes.c)
932 CONFIG_VIDEO_SED13806
933 Enable Epson SED13806 driver. This driver supports 8bpp
934 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
935 or CONFIG_VIDEO_SED13806_16BPP
940 Define this to enable a custom keyboard support.
941 This simply calls drv_keyboard_init() which must be
942 defined in your board-specific files.
943 The only board using this so far is RBC823.
945 - LCD Support: CONFIG_LCD
947 Define this to enable LCD support (for output to LCD
948 display); also select one of the supported displays
949 by defining one of these:
951 CONFIG_NEC_NL6448AC33:
953 NEC NL6448AC33-18. Active, color, single scan.
955 CONFIG_NEC_NL6448BC20
957 NEC NL6448BC20-08. 6.5", 640x480.
958 Active, color, single scan.
960 CONFIG_NEC_NL6448BC33_54
962 NEC NL6448BC33-54. 10.4", 640x480.
963 Active, color, single scan.
967 Sharp 320x240. Active, color, single scan.
968 It isn't 16x9, and I am not sure what it is.
970 CONFIG_SHARP_LQ64D341
972 Sharp LQ64D341 display, 640x480.
973 Active, color, single scan.
977 HLD1045 display, 640x480.
978 Active, color, single scan.
982 Optrex CBL50840-2 NF-FW 99 22 M5
984 Hitachi LMG6912RPFC-00T
988 320x240. Black & white.
990 Normally display is black on white background; define
991 CFG_WHITE_ON_BLACK to get it inverted.
993 - Splash Screen Support: CONFIG_SPLASH_SCREEN
995 If this option is set, the environment is checked for
996 a variable "splashimage". If found, the usual display
997 of logo, copyright and system information on the LCD
998 is suppressed and the BMP image at the address
999 specified in "splashimage" is loaded instead. The
1000 console is redirected to the "nulldev", too. This
1001 allows for a "silent" boot where a splash screen is
1002 loaded very quickly after power-on.
1004 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1006 If this option is set, additionally to standard BMP
1007 images, gzipped BMP images can be displayed via the
1008 splashscreen support or the bmp command.
1010 - Compression support:
1013 If this option is set, support for bzip2 compressed
1014 images is included. If not, only uncompressed and gzip
1015 compressed images are supported.
1017 NOTE: the bzip2 algorithm requires a lot of RAM, so
1018 the malloc area (as defined by CFG_MALLOC_LEN) should
1024 The address of PHY on MII bus.
1026 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1028 The clock frequency of the MII bus
1032 If this option is set, support for speed/duplex
1033 detection of Gigabit PHY is included.
1035 CONFIG_PHY_RESET_DELAY
1037 Some PHY like Intel LXT971A need extra delay after
1038 reset before any MII register access is possible.
1039 For such PHY, set this option to the usec delay
1040 required. (minimum 300usec for LXT971A)
1042 CONFIG_PHY_CMD_DELAY (ppc4xx)
1044 Some PHY like Intel LXT971A need extra delay after
1045 command issued before MII status register can be read
1052 Define a default value for ethernet address to use
1053 for the respective ethernet interface, in case this
1054 is not determined automatically.
1059 Define a default value for the IP address to use for
1060 the default ethernet interface, in case this is not
1061 determined through e.g. bootp.
1063 - Server IP address:
1066 Defines a default value for theIP address of a TFTP
1067 server to contact when using the "tftboot" command.
1069 - Multicast TFTP Mode:
1072 Defines whether you want to support multicast TFTP as per
1073 rfc-2090; for example to work with atftp. Lets lots of targets
1074 tftp down the same boot image concurrently. Note: the ethernet
1075 driver in use must provide a function: mcast() to join/leave a
1078 CONFIG_BOOTP_RANDOM_DELAY
1079 - BOOTP Recovery Mode:
1080 CONFIG_BOOTP_RANDOM_DELAY
1082 If you have many targets in a network that try to
1083 boot using BOOTP, you may want to avoid that all
1084 systems send out BOOTP requests at precisely the same
1085 moment (which would happen for instance at recovery
1086 from a power failure, when all systems will try to
1087 boot, thus flooding the BOOTP server. Defining
1088 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1089 inserted before sending out BOOTP requests. The
1090 following delays are inserted then:
1092 1st BOOTP request: delay 0 ... 1 sec
1093 2nd BOOTP request: delay 0 ... 2 sec
1094 3rd BOOTP request: delay 0 ... 4 sec
1096 BOOTP requests: delay 0 ... 8 sec
1098 - DHCP Advanced Options:
1099 You can fine tune the DHCP functionality by defining
1100 CONFIG_BOOTP_* symbols:
1102 CONFIG_BOOTP_SUBNETMASK
1103 CONFIG_BOOTP_GATEWAY
1104 CONFIG_BOOTP_HOSTNAME
1105 CONFIG_BOOTP_NISDOMAIN
1106 CONFIG_BOOTP_BOOTPATH
1107 CONFIG_BOOTP_BOOTFILESIZE
1110 CONFIG_BOOTP_SEND_HOSTNAME
1111 CONFIG_BOOTP_NTPSERVER
1112 CONFIG_BOOTP_TIMEOFFSET
1113 CONFIG_BOOTP_VENDOREX
1115 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1116 environment variable, not the BOOTP server.
1118 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1119 serverip from a DHCP server, it is possible that more
1120 than one DNS serverip is offered to the client.
1121 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1122 serverip will be stored in the additional environment
1123 variable "dnsip2". The first DNS serverip is always
1124 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1127 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1128 to do a dynamic update of a DNS server. To do this, they
1129 need the hostname of the DHCP requester.
1130 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1131 of the "hostname" environment variable is passed as
1132 option 12 to the DHCP server.
1135 CONFIG_CDP_DEVICE_ID
1137 The device id used in CDP trigger frames.
1139 CONFIG_CDP_DEVICE_ID_PREFIX
1141 A two character string which is prefixed to the MAC address
1146 A printf format string which contains the ascii name of
1147 the port. Normally is set to "eth%d" which sets
1148 eth0 for the first ethernet, eth1 for the second etc.
1150 CONFIG_CDP_CAPABILITIES
1152 A 32bit integer which indicates the device capabilities;
1153 0x00000010 for a normal host which does not forwards.
1157 An ascii string containing the version of the software.
1161 An ascii string containing the name of the platform.
1165 A 32bit integer sent on the trigger.
1167 CONFIG_CDP_POWER_CONSUMPTION
1169 A 16bit integer containing the power consumption of the
1170 device in .1 of milliwatts.
1172 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1174 A byte containing the id of the VLAN.
1176 - Status LED: CONFIG_STATUS_LED
1178 Several configurations allow to display the current
1179 status using a LED. For instance, the LED will blink
1180 fast while running U-Boot code, stop blinking as
1181 soon as a reply to a BOOTP request was received, and
1182 start blinking slow once the Linux kernel is running
1183 (supported by a status LED driver in the Linux
1184 kernel). Defining CONFIG_STATUS_LED enables this
1187 - CAN Support: CONFIG_CAN_DRIVER
1189 Defining CONFIG_CAN_DRIVER enables CAN driver support
1190 on those systems that support this (optional)
1191 feature, like the TQM8xxL modules.
1193 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1195 These enable I2C serial bus commands. Defining either of
1196 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1197 include the appropriate I2C driver for the selected cpu.
1199 This will allow you to use i2c commands at the u-boot
1200 command line (as long as you set CONFIG_CMD_I2C in
1201 CONFIG_COMMANDS) and communicate with i2c based realtime
1202 clock chips. See common/cmd_i2c.c for a description of the
1203 command line interface.
1205 CONFIG_I2C_CMD_TREE is a recommended option that places
1206 all I2C commands under a single 'i2c' root command. The
1207 older 'imm', 'imd', 'iprobe' etc. commands are considered
1208 deprecated and may disappear in the future.
1210 CONFIG_HARD_I2C selects a hardware I2C controller.
1212 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1213 bit-banging) driver instead of CPM or similar hardware
1216 There are several other quantities that must also be
1217 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1219 In both cases you will need to define CFG_I2C_SPEED
1220 to be the frequency (in Hz) at which you wish your i2c bus
1221 to run and CFG_I2C_SLAVE to be the address of this node (ie
1222 the cpu's i2c node address).
1224 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1225 sets the cpu up as a master node and so its address should
1226 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1227 p.16-473). So, set CFG_I2C_SLAVE to 0.
1229 That's all that's required for CONFIG_HARD_I2C.
1231 If you use the software i2c interface (CONFIG_SOFT_I2C)
1232 then the following macros need to be defined (examples are
1233 from include/configs/lwmon.h):
1237 (Optional). Any commands necessary to enable the I2C
1238 controller or configure ports.
1240 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1244 (Only for MPC8260 CPU). The I/O port to use (the code
1245 assumes both bits are on the same port). Valid values
1246 are 0..3 for ports A..D.
1250 The code necessary to make the I2C data line active
1251 (driven). If the data line is open collector, this
1254 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1258 The code necessary to make the I2C data line tri-stated
1259 (inactive). If the data line is open collector, this
1262 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1266 Code that returns TRUE if the I2C data line is high,
1269 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1273 If <bit> is TRUE, sets the I2C data line high. If it
1274 is FALSE, it clears it (low).
1276 eg: #define I2C_SDA(bit) \
1277 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1278 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1282 If <bit> is TRUE, sets the I2C clock line high. If it
1283 is FALSE, it clears it (low).
1285 eg: #define I2C_SCL(bit) \
1286 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1287 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1291 This delay is invoked four times per clock cycle so this
1292 controls the rate of data transfer. The data rate thus
1293 is 1 / (I2C_DELAY * 4). Often defined to be something
1296 #define I2C_DELAY udelay(2)
1300 When a board is reset during an i2c bus transfer
1301 chips might think that the current transfer is still
1302 in progress. On some boards it is possible to access
1303 the i2c SCLK line directly, either by using the
1304 processor pin as a GPIO or by having a second pin
1305 connected to the bus. If this option is defined a
1306 custom i2c_init_board() routine in boards/xxx/board.c
1307 is run early in the boot sequence.
1309 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1311 This option enables configuration of bi_iic_fast[] flags
1312 in u-boot bd_info structure based on u-boot environment
1313 variable "i2cfast". (see also i2cfast)
1315 CONFIG_I2C_MULTI_BUS
1317 This option allows the use of multiple I2C buses, each of which
1318 must have a controller. At any point in time, only one bus is
1319 active. To switch to a different bus, use the 'i2c dev' command.
1320 Note that bus numbering is zero-based.
1324 This option specifies a list of I2C devices that will be skipped
1325 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1326 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1327 pairs. Otherwise, specify a 1D array of device addresses
1330 #undef CONFIG_I2C_MULTI_BUS
1331 #define CFG_I2C_NOPROBES {0x50,0x68}
1333 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1335 #define CONFIG_I2C_MULTI_BUS
1336 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1338 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1342 If defined, then this indicates the I2C bus number for DDR SPD.
1343 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1347 If defined, then this indicates the I2C bus number for the RTC.
1348 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1352 If defined, then this indicates the I2C bus number for the DTT.
1353 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1357 Define this option if you want to use Freescale's I2C driver in
1358 drivers/i2c/fsl_i2c.c.
1361 - SPI Support: CONFIG_SPI
1363 Enables SPI driver (so far only tested with
1364 SPI EEPROM, also an instance works with Crystal A/D and
1365 D/As on the SACSng board)
1369 Enables extended (16-bit) SPI EEPROM addressing.
1370 (symmetrical to CONFIG_I2C_X)
1374 Enables a software (bit-bang) SPI driver rather than
1375 using hardware support. This is a general purpose
1376 driver that only requires three general I/O port pins
1377 (two outputs, one input) to function. If this is
1378 defined, the board configuration must define several
1379 SPI configuration items (port pins to use, etc). For
1380 an example, see include/configs/sacsng.h.
1382 - FPGA Support: CONFIG_FPGA
1384 Enables FPGA subsystem.
1386 CONFIG_FPGA_<vendor>
1388 Enables support for specific chip vendors.
1391 CONFIG_FPGA_<family>
1393 Enables support for FPGA family.
1394 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1398 Specify the number of FPGA devices to support.
1400 CFG_FPGA_PROG_FEEDBACK
1402 Enable printing of hash marks during FPGA configuration.
1406 Enable checks on FPGA configuration interface busy
1407 status by the configuration function. This option
1408 will require a board or device specific function to
1413 If defined, a function that provides delays in the FPGA
1414 configuration driver.
1416 CFG_FPGA_CHECK_CTRLC
1417 Allow Control-C to interrupt FPGA configuration
1419 CFG_FPGA_CHECK_ERROR
1421 Check for configuration errors during FPGA bitfile
1422 loading. For example, abort during Virtex II
1423 configuration if the INIT_B line goes low (which
1424 indicated a CRC error).
1428 Maximum time to wait for the INIT_B line to deassert
1429 after PROB_B has been deasserted during a Virtex II
1430 FPGA configuration sequence. The default time is 500
1435 Maximum time to wait for BUSY to deassert during
1436 Virtex II FPGA configuration. The default is 5 mS.
1438 CFG_FPGA_WAIT_CONFIG
1440 Time to wait after FPGA configuration. The default is
1443 - Configuration Management:
1446 If defined, this string will be added to the U-Boot
1447 version information (U_BOOT_VERSION)
1449 - Vendor Parameter Protection:
1451 U-Boot considers the values of the environment
1452 variables "serial#" (Board Serial Number) and
1453 "ethaddr" (Ethernet Address) to be parameters that
1454 are set once by the board vendor / manufacturer, and
1455 protects these variables from casual modification by
1456 the user. Once set, these variables are read-only,
1457 and write or delete attempts are rejected. You can
1458 change this behviour:
1460 If CONFIG_ENV_OVERWRITE is #defined in your config
1461 file, the write protection for vendor parameters is
1462 completely disabled. Anybody can change or delete
1465 Alternatively, if you #define _both_ CONFIG_ETHADDR
1466 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1467 ethernet address is installed in the environment,
1468 which can be changed exactly ONCE by the user. [The
1469 serial# is unaffected by this, i. e. it remains
1475 Define this variable to enable the reservation of
1476 "protected RAM", i. e. RAM which is not overwritten
1477 by U-Boot. Define CONFIG_PRAM to hold the number of
1478 kB you want to reserve for pRAM. You can overwrite
1479 this default value by defining an environment
1480 variable "pram" to the number of kB you want to
1481 reserve. Note that the board info structure will
1482 still show the full amount of RAM. If pRAM is
1483 reserved, a new environment variable "mem" will
1484 automatically be defined to hold the amount of
1485 remaining RAM in a form that can be passed as boot
1486 argument to Linux, for instance like that:
1488 setenv bootargs ... mem=\${mem}
1491 This way you can tell Linux not to use this memory,
1492 either, which results in a memory region that will
1493 not be affected by reboots.
1495 *WARNING* If your board configuration uses automatic
1496 detection of the RAM size, you must make sure that
1497 this memory test is non-destructive. So far, the
1498 following board configurations are known to be
1501 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1502 HERMES, IP860, RPXlite, LWMON, LANTEC,
1503 PCU_E, FLAGADM, TQM8260
1508 Define this variable to stop the system in case of a
1509 fatal error, so that you have to reset it manually.
1510 This is probably NOT a good idea for an embedded
1511 system where you want to system to reboot
1512 automatically as fast as possible, but it may be
1513 useful during development since you can try to debug
1514 the conditions that lead to the situation.
1516 CONFIG_NET_RETRY_COUNT
1518 This variable defines the number of retries for
1519 network operations like ARP, RARP, TFTP, or BOOTP
1520 before giving up the operation. If not defined, a
1521 default value of 5 is used.
1523 - Command Interpreter:
1524 CONFIG_AUTO_COMPLETE
1526 Enable auto completion of commands using TAB.
1528 Note that this feature has NOT been implemented yet
1529 for the "hush" shell.
1534 Define this variable to enable the "hush" shell (from
1535 Busybox) as command line interpreter, thus enabling
1536 powerful command line syntax like
1537 if...then...else...fi conditionals or `&&' and '||'
1538 constructs ("shell scripts").
1540 If undefined, you get the old, much simpler behaviour
1541 with a somewhat smaller memory footprint.
1546 This defines the secondary prompt string, which is
1547 printed when the command interpreter needs more input
1548 to complete a command. Usually "> ".
1552 In the current implementation, the local variables
1553 space and global environment variables space are
1554 separated. Local variables are those you define by
1555 simply typing `name=value'. To access a local
1556 variable later on, you have write `$name' or
1557 `${name}'; to execute the contents of a variable
1558 directly type `$name' at the command prompt.
1560 Global environment variables are those you use
1561 setenv/printenv to work with. To run a command stored
1562 in such a variable, you need to use the run command,
1563 and you must not use the '$' sign to access them.
1565 To store commands and special characters in a
1566 variable, please use double quotation marks
1567 surrounding the whole text of the variable, instead
1568 of the backslashes before semicolons and special
1571 - Commandline Editing and History:
1572 CONFIG_CMDLINE_EDITING
1574 Enable editiong and History functions for interactive
1575 commandline input operations
1577 - Default Environment:
1578 CONFIG_EXTRA_ENV_SETTINGS
1580 Define this to contain any number of null terminated
1581 strings (variable = value pairs) that will be part of
1582 the default environment compiled into the boot image.
1584 For example, place something like this in your
1585 board's config file:
1587 #define CONFIG_EXTRA_ENV_SETTINGS \
1591 Warning: This method is based on knowledge about the
1592 internal format how the environment is stored by the
1593 U-Boot code. This is NOT an official, exported
1594 interface! Although it is unlikely that this format
1595 will change soon, there is no guarantee either.
1596 You better know what you are doing here.
1598 Note: overly (ab)use of the default environment is
1599 discouraged. Make sure to check other ways to preset
1600 the environment like the autoscript function or the
1603 - DataFlash Support:
1604 CONFIG_HAS_DATAFLASH
1606 Defining this option enables DataFlash features and
1607 allows to read/write in Dataflash via the standard
1610 - SystemACE Support:
1613 Adding this option adds support for Xilinx SystemACE
1614 chips attached via some sort of local bus. The address
1615 of the chip must alsh be defined in the
1616 CFG_SYSTEMACE_BASE macro. For example:
1618 #define CONFIG_SYSTEMACE
1619 #define CFG_SYSTEMACE_BASE 0xf0000000
1621 When SystemACE support is added, the "ace" device type
1622 becomes available to the fat commands, i.e. fatls.
1624 - TFTP Fixed UDP Port:
1627 If this is defined, the environment variable tftpsrcp
1628 is used to supply the TFTP UDP source port value.
1629 If tftpsrcp isn't defined, the normal pseudo-random port
1630 number generator is used.
1632 Also, the environment variable tftpdstp is used to supply
1633 the TFTP UDP destination port value. If tftpdstp isn't
1634 defined, the normal port 69 is used.
1636 The purpose for tftpsrcp is to allow a TFTP server to
1637 blindly start the TFTP transfer using the pre-configured
1638 target IP address and UDP port. This has the effect of
1639 "punching through" the (Windows XP) firewall, allowing
1640 the remainder of the TFTP transfer to proceed normally.
1641 A better solution is to properly configure the firewall,
1642 but sometimes that is not allowed.
1644 - Show boot progress:
1645 CONFIG_SHOW_BOOT_PROGRESS
1647 Defining this option allows to add some board-
1648 specific code (calling a user-provided function
1649 "show_boot_progress(int)") that enables you to show
1650 the system's boot progress on some display (for
1651 example, some LED's) on your board. At the moment,
1652 the following checkpoints are implemented:
1655 1 common/cmd_bootm.c before attempting to boot an image
1656 -1 common/cmd_bootm.c Image header has bad magic number
1657 2 common/cmd_bootm.c Image header has correct magic number
1658 -2 common/cmd_bootm.c Image header has bad checksum
1659 3 common/cmd_bootm.c Image header has correct checksum
1660 -3 common/cmd_bootm.c Image data has bad checksum
1661 4 common/cmd_bootm.c Image data has correct checksum
1662 -4 common/cmd_bootm.c Image is for unsupported architecture
1663 5 common/cmd_bootm.c Architecture check OK
1664 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1665 6 common/cmd_bootm.c Image Type check OK
1666 -6 common/cmd_bootm.c gunzip uncompression error
1667 -7 common/cmd_bootm.c Unimplemented compression type
1668 7 common/cmd_bootm.c Uncompression OK
1669 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1670 8 common/cmd_bootm.c Image Type check OK
1671 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1672 9 common/cmd_bootm.c Start initial ramdisk verification
1673 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1674 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1675 10 common/cmd_bootm.c Ramdisk header is OK
1676 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1677 11 common/cmd_bootm.c Ramdisk data has correct checksum
1678 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1679 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1680 13 common/cmd_bootm.c Start multifile image verification
1681 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1682 15 common/cmd_bootm.c All preparation done, transferring control to OS
1684 -30 lib_ppc/board.c Fatal error, hang the system
1685 -31 post/post.c POST test failed, detected by post_output_backlog()
1686 -32 post/post.c POST test failed, detected by post_run_single()
1688 34 common/cmd_doc.c before loading a Image from a DOC device
1689 -35 common/cmd_doc.c Bad usage of "doc" command
1690 35 common/cmd_doc.c correct usage of "doc" command
1691 -36 common/cmd_doc.c No boot device
1692 36 common/cmd_doc.c correct boot device
1693 -37 common/cmd_doc.c Unknown Chip ID on boot device
1694 37 common/cmd_doc.c correct chip ID found, device available
1695 -38 common/cmd_doc.c Read Error on boot device
1696 38 common/cmd_doc.c reading Image header from DOC device OK
1697 -39 common/cmd_doc.c Image header has bad magic number
1698 39 common/cmd_doc.c Image header has correct magic number
1699 -40 common/cmd_doc.c Error reading Image from DOC device
1700 40 common/cmd_doc.c Image header has correct magic number
1701 41 common/cmd_ide.c before loading a Image from a IDE device
1702 -42 common/cmd_ide.c Bad usage of "ide" command
1703 42 common/cmd_ide.c correct usage of "ide" command
1704 -43 common/cmd_ide.c No boot device
1705 43 common/cmd_ide.c boot device found
1706 -44 common/cmd_ide.c Device not available
1707 44 common/cmd_ide.c Device available
1708 -45 common/cmd_ide.c wrong partition selected
1709 45 common/cmd_ide.c partition selected
1710 -46 common/cmd_ide.c Unknown partition table
1711 46 common/cmd_ide.c valid partition table found
1712 -47 common/cmd_ide.c Invalid partition type
1713 47 common/cmd_ide.c correct partition type
1714 -48 common/cmd_ide.c Error reading Image Header on boot device
1715 48 common/cmd_ide.c reading Image Header from IDE device OK
1716 -49 common/cmd_ide.c Image header has bad magic number
1717 49 common/cmd_ide.c Image header has correct magic number
1718 -50 common/cmd_ide.c Image header has bad checksum
1719 50 common/cmd_ide.c Image header has correct checksum
1720 -51 common/cmd_ide.c Error reading Image from IDE device
1721 51 common/cmd_ide.c reading Image from IDE device OK
1722 52 common/cmd_nand.c before loading a Image from a NAND device
1723 -53 common/cmd_nand.c Bad usage of "nand" command
1724 53 common/cmd_nand.c correct usage of "nand" command
1725 -54 common/cmd_nand.c No boot device
1726 54 common/cmd_nand.c boot device found
1727 -55 common/cmd_nand.c Unknown Chip ID on boot device
1728 55 common/cmd_nand.c correct chip ID found, device available
1729 -56 common/cmd_nand.c Error reading Image Header on boot device
1730 56 common/cmd_nand.c reading Image Header from NAND device OK
1731 -57 common/cmd_nand.c Image header has bad magic number
1732 57 common/cmd_nand.c Image header has correct magic number
1733 -58 common/cmd_nand.c Error reading Image from NAND device
1734 58 common/cmd_nand.c reading Image from NAND device OK
1736 -60 common/env_common.c Environment has a bad CRC, using default
1738 64 net/eth.c starting with Ethernetconfiguration.
1739 -64 net/eth.c no Ethernet found.
1740 65 net/eth.c Ethernet found.
1742 -80 common/cmd_net.c usage wrong
1743 80 common/cmd_net.c before calling NetLoop()
1744 -81 common/cmd_net.c some error in NetLoop() occured
1745 81 common/cmd_net.c NetLoop() back without error
1746 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1747 82 common/cmd_net.c trying automatic boot
1748 83 common/cmd_net.c running autoscript
1749 -83 common/cmd_net.c some error in automatic boot or autoscript
1750 84 common/cmd_net.c end without errors
1755 [so far only for SMDK2400 and TRAB boards]
1757 - Modem support endable:
1758 CONFIG_MODEM_SUPPORT
1760 - RTS/CTS Flow control enable:
1763 - Modem debug support:
1764 CONFIG_MODEM_SUPPORT_DEBUG
1766 Enables debugging stuff (char screen[1024], dbg())
1767 for modem support. Useful only with BDI2000.
1769 - Interrupt support (PPC):
1771 There are common interrupt_init() and timer_interrupt()
1772 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1773 for cpu specific initialization. interrupt_init_cpu()
1774 should set decrementer_count to appropriate value. If
1775 cpu resets decrementer automatically after interrupt
1776 (ppc4xx) it should set decrementer_count to zero.
1777 timer_interrupt() calls timer_interrupt_cpu() for cpu
1778 specific handling. If board has watchdog / status_led
1779 / other_activity_monitor it works automatically from
1780 general timer_interrupt().
1784 In the target system modem support is enabled when a
1785 specific key (key combination) is pressed during
1786 power-on. Otherwise U-Boot will boot normally
1787 (autoboot). The key_pressed() fuction is called from
1788 board_init(). Currently key_pressed() is a dummy
1789 function, returning 1 and thus enabling modem
1792 If there are no modem init strings in the
1793 environment, U-Boot proceed to autoboot; the
1794 previous output (banner, info printfs) will be
1797 See also: doc/README.Modem
1800 Configuration Settings:
1801 -----------------------
1803 - CFG_LONGHELP: Defined when you want long help messages included;
1804 undefine this when you're short of memory.
1806 - CFG_PROMPT: This is what U-Boot prints on the console to
1807 prompt for user input.
1809 - CFG_CBSIZE: Buffer size for input from the Console
1811 - CFG_PBSIZE: Buffer size for Console output
1813 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1815 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1816 the application (usually a Linux kernel) when it is
1819 - CFG_BAUDRATE_TABLE:
1820 List of legal baudrate settings for this board.
1822 - CFG_CONSOLE_INFO_QUIET
1823 Suppress display of console information at boot.
1825 - CFG_CONSOLE_IS_IN_ENV
1826 If the board specific function
1827 extern int overwrite_console (void);
1828 returns 1, the stdin, stderr and stdout are switched to the
1829 serial port, else the settings in the environment are used.
1831 - CFG_CONSOLE_OVERWRITE_ROUTINE
1832 Enable the call to overwrite_console().
1834 - CFG_CONSOLE_ENV_OVERWRITE
1835 Enable overwrite of previous console environment settings.
1837 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1838 Begin and End addresses of the area used by the
1842 Enable an alternate, more extensive memory test.
1844 - CFG_MEMTEST_SCRATCH:
1845 Scratch address used by the alternate memory test
1846 You only need to set this if address zero isn't writeable
1848 - CFG_TFTP_LOADADDR:
1849 Default load address for network file downloads
1851 - CFG_LOADS_BAUD_CHANGE:
1852 Enable temporary baudrate change while serial download
1855 Physical start address of SDRAM. _Must_ be 0 here.
1858 Physical start address of Motherboard I/O (if using a
1862 Physical start address of Flash memory.
1865 Physical start address of boot monitor code (set by
1866 make config files to be same as the text base address
1867 (TEXT_BASE) used when linking) - same as
1868 CFG_FLASH_BASE when booting from flash.
1871 Size of memory reserved for monitor code, used to
1872 determine _at_compile_time_ (!) if the environment is
1873 embedded within the U-Boot image, or in a separate
1877 Size of DRAM reserved for malloc() use.
1880 Normally compressed uImages are limited to an
1881 uncompressed size of 8 MBytes. If this is not enough,
1882 you can define CFG_BOOTM_LEN in your board config file
1883 to adjust this setting to your needs.
1886 Maximum size of memory mapped by the startup code of
1887 the Linux kernel; all data that must be processed by
1888 the Linux kernel (bd_info, boot arguments, eventually
1889 initrd image) must be put below this limit.
1891 - CFG_MAX_FLASH_BANKS:
1892 Max number of Flash memory banks
1894 - CFG_MAX_FLASH_SECT:
1895 Max number of sectors on a Flash chip
1897 - CFG_FLASH_ERASE_TOUT:
1898 Timeout for Flash erase operations (in ms)
1900 - CFG_FLASH_WRITE_TOUT:
1901 Timeout for Flash write operations (in ms)
1903 - CFG_FLASH_LOCK_TOUT
1904 Timeout for Flash set sector lock bit operation (in ms)
1906 - CFG_FLASH_UNLOCK_TOUT
1907 Timeout for Flash clear lock bits operation (in ms)
1909 - CFG_FLASH_PROTECTION
1910 If defined, hardware flash sectors protection is used
1911 instead of U-Boot software protection.
1913 - CFG_DIRECT_FLASH_TFTP:
1915 Enable TFTP transfers directly to flash memory;
1916 without this option such a download has to be
1917 performed in two steps: (1) download to RAM, and (2)
1918 copy from RAM to flash.
1920 The two-step approach is usually more reliable, since
1921 you can check if the download worked before you erase
1922 the flash, but in some situations (when sytem RAM is
1923 too limited to allow for a tempory copy of the
1924 downloaded image) this option may be very useful.
1927 Define if the flash driver uses extra elements in the
1928 common flash structure for storing flash geometry.
1930 - CFG_FLASH_CFI_DRIVER
1931 This option also enables the building of the cfi_flash driver
1932 in the drivers directory
1934 - CFG_FLASH_QUIET_TEST
1935 If this option is defined, the common CFI flash doesn't
1936 print it's warning upon not recognized FLASH banks. This
1937 is useful, if some of the configured banks are only
1938 optionally available.
1940 - CFG_RX_ETH_BUFFER:
1941 Defines the number of ethernet receive buffers. On some
1942 ethernet controllers it is recommended to set this value
1943 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1944 buffers can be full shortly after enabling the interface
1945 on high ethernet traffic.
1946 Defaults to 4 if not defined.
1948 The following definitions that deal with the placement and management
1949 of environment data (variable area); in general, we support the
1950 following configurations:
1952 - CFG_ENV_IS_IN_FLASH:
1954 Define this if the environment is in flash memory.
1956 a) The environment occupies one whole flash sector, which is
1957 "embedded" in the text segment with the U-Boot code. This
1958 happens usually with "bottom boot sector" or "top boot
1959 sector" type flash chips, which have several smaller
1960 sectors at the start or the end. For instance, such a
1961 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1962 such a case you would place the environment in one of the
1963 4 kB sectors - with U-Boot code before and after it. With
1964 "top boot sector" type flash chips, you would put the
1965 environment in one of the last sectors, leaving a gap
1966 between U-Boot and the environment.
1970 Offset of environment data (variable area) to the
1971 beginning of flash memory; for instance, with bottom boot
1972 type flash chips the second sector can be used: the offset
1973 for this sector is given here.
1975 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1979 This is just another way to specify the start address of
1980 the flash sector containing the environment (instead of
1983 - CFG_ENV_SECT_SIZE:
1985 Size of the sector containing the environment.
1988 b) Sometimes flash chips have few, equal sized, BIG sectors.
1989 In such a case you don't want to spend a whole sector for
1994 If you use this in combination with CFG_ENV_IS_IN_FLASH
1995 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1996 of this flash sector for the environment. This saves
1997 memory for the RAM copy of the environment.
1999 It may also save flash memory if you decide to use this
2000 when your environment is "embedded" within U-Boot code,
2001 since then the remainder of the flash sector could be used
2002 for U-Boot code. It should be pointed out that this is
2003 STRONGLY DISCOURAGED from a robustness point of view:
2004 updating the environment in flash makes it always
2005 necessary to erase the WHOLE sector. If something goes
2006 wrong before the contents has been restored from a copy in
2007 RAM, your target system will be dead.
2009 - CFG_ENV_ADDR_REDUND
2012 These settings describe a second storage area used to hold
2013 a redundand copy of the environment data, so that there is
2014 a valid backup copy in case there is a power failure during
2015 a "saveenv" operation.
2017 BE CAREFUL! Any changes to the flash layout, and some changes to the
2018 source code will make it necessary to adapt <board>/u-boot.lds*
2022 - CFG_ENV_IS_IN_NVRAM:
2024 Define this if you have some non-volatile memory device
2025 (NVRAM, battery buffered SRAM) which you want to use for the
2031 These two #defines are used to determin the memory area you
2032 want to use for environment. It is assumed that this memory
2033 can just be read and written to, without any special
2036 BE CAREFUL! The first access to the environment happens quite early
2037 in U-Boot initalization (when we try to get the setting of for the
2038 console baudrate). You *MUST* have mappend your NVRAM area then, or
2041 Please note that even with NVRAM we still use a copy of the
2042 environment in RAM: we could work on NVRAM directly, but we want to
2043 keep settings there always unmodified except somebody uses "saveenv"
2044 to save the current settings.
2047 - CFG_ENV_IS_IN_EEPROM:
2049 Use this if you have an EEPROM or similar serial access
2050 device and a driver for it.
2055 These two #defines specify the offset and size of the
2056 environment area within the total memory of your EEPROM.
2058 - CFG_I2C_EEPROM_ADDR:
2059 If defined, specified the chip address of the EEPROM device.
2060 The default address is zero.
2062 - CFG_EEPROM_PAGE_WRITE_BITS:
2063 If defined, the number of bits used to address bytes in a
2064 single page in the EEPROM device. A 64 byte page, for example
2065 would require six bits.
2067 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2068 If defined, the number of milliseconds to delay between
2069 page writes. The default is zero milliseconds.
2071 - CFG_I2C_EEPROM_ADDR_LEN:
2072 The length in bytes of the EEPROM memory array address. Note
2073 that this is NOT the chip address length!
2075 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2076 EEPROM chips that implement "address overflow" are ones
2077 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2078 address and the extra bits end up in the "chip address" bit
2079 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2082 Note that we consider the length of the address field to
2083 still be one byte because the extra address bits are hidden
2084 in the chip address.
2087 The size in bytes of the EEPROM device.
2090 - CFG_ENV_IS_IN_DATAFLASH:
2092 Define this if you have a DataFlash memory device which you
2093 want to use for the environment.
2099 These three #defines specify the offset and size of the
2100 environment area within the total memory of your DataFlash placed
2101 at the specified address.
2103 - CFG_ENV_IS_IN_NAND:
2105 Define this if you have a NAND device which you want to use
2106 for the environment.
2111 These two #defines specify the offset and size of the environment
2112 area within the first NAND device.
2114 - CFG_ENV_OFFSET_REDUND
2116 This setting describes a second storage area of CFG_ENV_SIZE
2117 size used to hold a redundant copy of the environment data,
2118 so that there is a valid backup copy in case there is a
2119 power failure during a "saveenv" operation.
2121 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2122 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2123 the NAND devices block size.
2125 - CFG_SPI_INIT_OFFSET
2127 Defines offset to the initial SPI buffer area in DPRAM. The
2128 area is used at an early stage (ROM part) if the environment
2129 is configured to reside in the SPI EEPROM: We need a 520 byte
2130 scratch DPRAM area. It is used between the two initialization
2131 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2132 to be a good choice since it makes it far enough from the
2133 start of the data area as well as from the stack pointer.
2135 Please note that the environment is read-only until the monitor
2136 has been relocated to RAM and a RAM copy of the environment has been
2137 created; also, when using EEPROM you will have to use getenv_r()
2138 until then to read environment variables.
2140 The environment is protected by a CRC32 checksum. Before the monitor
2141 is relocated into RAM, as a result of a bad CRC you will be working
2142 with the compiled-in default environment - *silently*!!! [This is
2143 necessary, because the first environment variable we need is the
2144 "baudrate" setting for the console - if we have a bad CRC, we don't
2145 have any device yet where we could complain.]
2147 Note: once the monitor has been relocated, then it will complain if
2148 the default environment is used; a new CRC is computed as soon as you
2149 use the "saveenv" command to store a valid environment.
2151 - CFG_FAULT_ECHO_LINK_DOWN:
2152 Echo the inverted Ethernet link state to the fault LED.
2154 Note: If this option is active, then CFG_FAULT_MII_ADDR
2155 also needs to be defined.
2157 - CFG_FAULT_MII_ADDR:
2158 MII address of the PHY to check for the Ethernet link state.
2160 - CFG_64BIT_VSPRINTF:
2161 Makes vsprintf (and all *printf functions) support printing
2162 of 64bit values by using the L quantifier
2164 - CFG_64BIT_STRTOUL:
2165 Adds simple_strtoull that returns a 64bit value
2167 Low Level (hardware related) configuration options:
2168 ---------------------------------------------------
2170 - CFG_CACHELINE_SIZE:
2171 Cache Line Size of the CPU.
2174 Default address of the IMMR after system reset.
2176 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2177 and RPXsuper) to be able to adjust the position of
2178 the IMMR register after a reset.
2180 - Floppy Disk Support:
2181 CFG_FDC_DRIVE_NUMBER
2183 the default drive number (default value 0)
2187 defines the spacing between fdc chipset registers
2192 defines the offset of register from address. It
2193 depends on which part of the data bus is connected to
2194 the fdc chipset. (default value 0)
2196 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2197 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2200 if CFG_FDC_HW_INIT is defined, then the function
2201 fdc_hw_init() is called at the beginning of the FDC
2202 setup. fdc_hw_init() must be provided by the board
2203 source code. It is used to make hardware dependant
2206 - CFG_IMMR: Physical address of the Internal Memory.
2207 DO NOT CHANGE unless you know exactly what you're
2208 doing! (11-4) [MPC8xx/82xx systems only]
2210 - CFG_INIT_RAM_ADDR:
2212 Start address of memory area that can be used for
2213 initial data and stack; please note that this must be
2214 writable memory that is working WITHOUT special
2215 initialization, i. e. you CANNOT use normal RAM which
2216 will become available only after programming the
2217 memory controller and running certain initialization
2220 U-Boot uses the following memory types:
2221 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2222 - MPC824X: data cache
2223 - PPC4xx: data cache
2225 - CFG_GBL_DATA_OFFSET:
2227 Offset of the initial data structure in the memory
2228 area defined by CFG_INIT_RAM_ADDR. Usually
2229 CFG_GBL_DATA_OFFSET is chosen such that the initial
2230 data is located at the end of the available space
2231 (sometimes written as (CFG_INIT_RAM_END -
2232 CFG_INIT_DATA_SIZE), and the initial stack is just
2233 below that area (growing from (CFG_INIT_RAM_ADDR +
2234 CFG_GBL_DATA_OFFSET) downward.
2237 On the MPC824X (or other systems that use the data
2238 cache for initial memory) the address chosen for
2239 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2240 point to an otherwise UNUSED address space between
2241 the top of RAM and the start of the PCI space.
2243 - CFG_SIUMCR: SIU Module Configuration (11-6)
2245 - CFG_SYPCR: System Protection Control (11-9)
2247 - CFG_TBSCR: Time Base Status and Control (11-26)
2249 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2251 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2253 - CFG_SCCR: System Clock and reset Control Register (15-27)
2255 - CFG_OR_TIMING_SDRAM:
2259 periodic timer for refresh
2261 - CFG_DER: Debug Event Register (37-47)
2263 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2264 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2265 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2267 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2269 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2270 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2271 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2272 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2274 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2275 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2276 Machine Mode Register and Memory Periodic Timer
2277 Prescaler definitions (SDRAM timing)
2279 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2280 enable I2C microcode relocation patch (MPC8xx);
2281 define relocation offset in DPRAM [DSP2]
2283 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2284 enable SMC microcode relocation patch (MPC8xx);
2285 define relocation offset in DPRAM [SMC1]
2287 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2288 enable SPI microcode relocation patch (MPC8xx);
2289 define relocation offset in DPRAM [SCC4]
2292 Use OSCM clock mode on MBX8xx board. Be careful,
2293 wrong setting might damage your board. Read
2294 doc/README.MBX before setting this variable!
2296 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2297 Offset of the bootmode word in DPRAM used by post
2298 (Power On Self Tests). This definition overrides
2299 #define'd default value in commproc.h resp.
2302 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2303 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2304 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2305 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2306 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2307 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2308 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2309 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2310 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2313 Get DDR timing information from an I2C EEPROM. Common with pluggable
2314 memory modules such as SODIMMs
2316 I2C address of the SPD EEPROM
2319 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2320 Note that the value must resolve to something your driver can deal with.
2322 - CFG_83XX_DDR_USES_CS0
2323 Only for 83xx systems. If specified, then DDR should be configured
2324 using CS0 and CS1 instead of CS2 and CS3.
2326 - CFG_83XX_DDR_USES_CS0
2327 Only for 83xx systems. If specified, then DDR should be configured
2328 using CS0 and CS1 instead of CS2 and CS3.
2330 - CONFIG_ETHER_ON_FEC[12]
2331 Define to enable FEC[12] on a 8xx series processor.
2333 - CONFIG_FEC[12]_PHY
2334 Define to the hardcoded PHY address which corresponds
2335 to the given FEC; i. e.
2336 #define CONFIG_FEC1_PHY 4
2337 means that the PHY with address 4 is connected to FEC1
2339 When set to -1, means to probe for first available.
2341 - CONFIG_FEC[12]_PHY_NORXERR
2342 The PHY does not have a RXERR line (RMII only).
2343 (so program the FEC to ignore it).
2346 Enable RMII mode for all FECs.
2347 Note that this is a global option, we can't
2348 have one FEC in standard MII mode and another in RMII mode.
2350 - CONFIG_CRC32_VERIFY
2351 Add a verify option to the crc32 command.
2354 => crc32 -v <address> <count> <crc32>
2356 Where address/count indicate a memory area
2357 and crc32 is the correct crc32 which the
2361 Add the "loopw" memory command. This only takes effect if
2362 the memory commands are activated globally (CONFIG_CMD_MEM).
2365 Add the "mdc" and "mwc" memory commands. These are cyclic
2370 This command will print 4 bytes (10,11,12,13) each 500 ms.
2372 => mwc.l 100 12345678 10
2373 This command will write 12345678 to address 100 all 10 ms.
2375 This only takes effect if the memory commands are activated
2376 globally (CONFIG_CMD_MEM).
2378 - CONFIG_SKIP_LOWLEVEL_INIT
2379 - CONFIG_SKIP_RELOCATE_UBOOT
2381 [ARM only] If these variables are defined, then
2382 certain low level initializations (like setting up
2383 the memory controller) are omitted and/or U-Boot does
2384 not relocate itself into RAM.
2385 Normally these variables MUST NOT be defined. The
2386 only exception is when U-Boot is loaded (to RAM) by
2387 some other boot loader or by a debugger which
2388 performs these intializations itself.
2391 Building the Software:
2392 ======================
2394 Building U-Boot has been tested in native PPC environments (on a
2395 PowerBook G3 running LinuxPPC 2000) and in cross environments
2396 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2399 If you are not using a native PPC environment, it is assumed that you
2400 have the GNU cross compiling tools available in your path and named
2401 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2402 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2403 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2406 CROSS_COMPILE = ppc_4xx-
2409 U-Boot is intended to be simple to build. After installing the
2410 sources you must configure U-Boot for one specific board type. This
2415 where "NAME_config" is the name of one of the existing
2416 configurations; see the main Makefile for supported names.
2418 Note: for some board special configuration names may exist; check if
2419 additional information is available from the board vendor; for
2420 instance, the TQM823L systems are available without (standard)
2421 or with LCD support. You can select such additional "features"
2422 when chosing the configuration, i. e.
2425 - will configure for a plain TQM823L, i. e. no LCD support
2427 make TQM823L_LCD_config
2428 - will configure for a TQM823L with U-Boot console on LCD
2433 Finally, type "make all", and you should get some working U-Boot
2434 images ready for download to / installation on your system:
2436 - "u-boot.bin" is a raw binary image
2437 - "u-boot" is an image in ELF binary format
2438 - "u-boot.srec" is in Motorola S-Record format
2440 By default the build is performed locally and the objects are saved
2441 in the source directory. One of the two methods can be used to change
2442 this behavior and build U-Boot to some external directory:
2444 1. Add O= to the make command line invocations:
2446 make O=/tmp/build distclean
2447 make O=/tmp/build NAME_config
2448 make O=/tmp/build all
2450 2. Set environment variable BUILD_DIR to point to the desired location:
2452 export BUILD_DIR=/tmp/build
2457 Note that the command line "O=" setting overrides the BUILD_DIR environment
2461 Please be aware that the Makefiles assume you are using GNU make, so
2462 for instance on NetBSD you might need to use "gmake" instead of
2466 If the system board that you have is not listed, then you will need
2467 to port U-Boot to your hardware platform. To do this, follow these
2470 1. Add a new configuration option for your board to the toplevel
2471 "Makefile" and to the "MAKEALL" script, using the existing
2472 entries as examples. Note that here and at many other places
2473 boards and other names are listed in alphabetical sort order. Please
2475 2. Create a new directory to hold your board specific code. Add any
2476 files you need. In your board directory, you will need at least
2477 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2478 3. Create a new configuration file "include/configs/<board>.h" for
2480 3. If you're porting U-Boot to a new CPU, then also create a new
2481 directory to hold your CPU specific code. Add any files you need.
2482 4. Run "make <board>_config" with your new name.
2483 5. Type "make", and you should get a working "u-boot.srec" file
2484 to be installed on your target system.
2485 6. Debug and solve any problems that might arise.
2486 [Of course, this last step is much harder than it sounds.]
2489 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2490 ==============================================================
2492 If you have modified U-Boot sources (for instance added a new board
2493 or support for new devices, a new CPU, etc.) you are expected to
2494 provide feedback to the other developers. The feedback normally takes
2495 the form of a "patch", i. e. a context diff against a certain (latest
2496 official or latest in CVS) version of U-Boot sources.
2498 But before you submit such a patch, please verify that your modifi-
2499 cation did not break existing code. At least make sure that *ALL* of
2500 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2501 just run the "MAKEALL" script, which will configure and build U-Boot
2502 for ALL supported system. Be warned, this will take a while. You can
2503 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2504 environment variable to the script, i. e. to use the cross tools from
2505 MontaVista's Hard Hat Linux you can type
2507 CROSS_COMPILE=ppc_8xx- MAKEALL
2509 or to build on a native PowerPC system you can type
2511 CROSS_COMPILE=' ' MAKEALL
2513 When using the MAKEALL script, the default behaviour is to build U-Boot
2514 in the source directory. This location can be changed by setting the
2515 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2516 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2517 <source dir>/LOG directory. This default location can be changed by
2518 setting the MAKEALL_LOGDIR environment variable. For example:
2520 export BUILD_DIR=/tmp/build
2521 export MAKEALL_LOGDIR=/tmp/log
2522 CROSS_COMPILE=ppc_8xx- MAKEALL
2524 With the above settings build objects are saved in the /tmp/build, log
2525 files are saved in the /tmp/log and the source tree remains clean during
2526 the whole build process.
2529 See also "U-Boot Porting Guide" below.
2532 Monitor Commands - Overview:
2533 ============================
2535 go - start application at address 'addr'
2536 run - run commands in an environment variable
2537 bootm - boot application image from memory
2538 bootp - boot image via network using BootP/TFTP protocol
2539 tftpboot- boot image via network using TFTP protocol
2540 and env variables "ipaddr" and "serverip"
2541 (and eventually "gatewayip")
2542 rarpboot- boot image via network using RARP/TFTP protocol
2543 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2544 loads - load S-Record file over serial line
2545 loadb - load binary file over serial line (kermit mode)
2547 mm - memory modify (auto-incrementing)
2548 nm - memory modify (constant address)
2549 mw - memory write (fill)
2551 cmp - memory compare
2552 crc32 - checksum calculation
2553 imd - i2c memory display
2554 imm - i2c memory modify (auto-incrementing)
2555 inm - i2c memory modify (constant address)
2556 imw - i2c memory write (fill)
2557 icrc32 - i2c checksum calculation
2558 iprobe - probe to discover valid I2C chip addresses
2559 iloop - infinite loop on address range
2560 isdram - print SDRAM configuration information
2561 sspi - SPI utility commands
2562 base - print or set address offset
2563 printenv- print environment variables
2564 setenv - set environment variables
2565 saveenv - save environment variables to persistent storage
2566 protect - enable or disable FLASH write protection
2567 erase - erase FLASH memory
2568 flinfo - print FLASH memory information
2569 bdinfo - print Board Info structure
2570 iminfo - print header information for application image
2571 coninfo - print console devices and informations
2572 ide - IDE sub-system
2573 loop - infinite loop on address range
2574 loopw - infinite write loop on address range
2575 mtest - simple RAM test
2576 icache - enable or disable instruction cache
2577 dcache - enable or disable data cache
2578 reset - Perform RESET of the CPU
2579 echo - echo args to console
2580 version - print monitor version
2581 help - print online help
2582 ? - alias for 'help'
2585 Monitor Commands - Detailed Description:
2586 ========================================
2590 For now: just type "help <command>".
2593 Environment Variables:
2594 ======================
2596 U-Boot supports user configuration using Environment Variables which
2597 can be made persistent by saving to Flash memory.
2599 Environment Variables are set using "setenv", printed using
2600 "printenv", and saved to Flash using "saveenv". Using "setenv"
2601 without a value can be used to delete a variable from the
2602 environment. As long as you don't save the environment you are
2603 working with an in-memory copy. In case the Flash area containing the
2604 environment is erased by accident, a default environment is provided.
2606 Some configuration options can be set using Environment Variables:
2608 baudrate - see CONFIG_BAUDRATE
2610 bootdelay - see CONFIG_BOOTDELAY
2612 bootcmd - see CONFIG_BOOTCOMMAND
2614 bootargs - Boot arguments when booting an RTOS image
2616 bootfile - Name of the image to load with TFTP
2618 autoload - if set to "no" (any string beginning with 'n'),
2619 "bootp" will just load perform a lookup of the
2620 configuration from the BOOTP server, but not try to
2621 load any image using TFTP
2623 autostart - if set to "yes", an image loaded using the "bootp",
2624 "rarpboot", "tftpboot" or "diskboot" commands will
2625 be automatically started (by internally calling
2628 If set to "no", a standalone image passed to the
2629 "bootm" command will be copied to the load address
2630 (and eventually uncompressed), but NOT be started.
2631 This can be used to load and uncompress arbitrary
2634 i2cfast - (PPC405GP|PPC405EP only)
2635 if set to 'y' configures Linux I2C driver for fast
2636 mode (400kHZ). This environment variable is used in
2637 initialization code. So, for changes to be effective
2638 it must be saved and board must be reset.
2640 initrd_high - restrict positioning of initrd images:
2641 If this variable is not set, initrd images will be
2642 copied to the highest possible address in RAM; this
2643 is usually what you want since it allows for
2644 maximum initrd size. If for some reason you want to
2645 make sure that the initrd image is loaded below the
2646 CFG_BOOTMAPSZ limit, you can set this environment
2647 variable to a value of "no" or "off" or "0".
2648 Alternatively, you can set it to a maximum upper
2649 address to use (U-Boot will still check that it
2650 does not overwrite the U-Boot stack and data).
2652 For instance, when you have a system with 16 MB
2653 RAM, and want to reserve 4 MB from use by Linux,
2654 you can do this by adding "mem=12M" to the value of
2655 the "bootargs" variable. However, now you must make
2656 sure that the initrd image is placed in the first
2657 12 MB as well - this can be done with
2659 setenv initrd_high 00c00000
2661 If you set initrd_high to 0xFFFFFFFF, this is an
2662 indication to U-Boot that all addresses are legal
2663 for the Linux kernel, including addresses in flash
2664 memory. In this case U-Boot will NOT COPY the
2665 ramdisk at all. This may be useful to reduce the
2666 boot time on your system, but requires that this
2667 feature is supported by your Linux kernel.
2669 ipaddr - IP address; needed for tftpboot command
2671 loadaddr - Default load address for commands like "bootp",
2672 "rarpboot", "tftpboot", "loadb" or "diskboot"
2674 loads_echo - see CONFIG_LOADS_ECHO
2676 serverip - TFTP server IP address; needed for tftpboot command
2678 bootretry - see CONFIG_BOOT_RETRY_TIME
2680 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2682 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2684 ethprime - When CONFIG_NET_MULTI is enabled controls which
2685 interface is used first.
2687 ethact - When CONFIG_NET_MULTI is enabled controls which
2688 interface is currently active. For example you
2689 can do the following
2691 => setenv ethact FEC ETHERNET
2692 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2693 => setenv ethact SCC ETHERNET
2694 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2696 netretry - When set to "no" each network operation will
2697 either succeed or fail without retrying.
2698 When set to "once" the network operation will
2699 fail when all the available network interfaces
2700 are tried once without success.
2701 Useful on scripts which control the retry operation
2704 tftpsrcport - If this is set, the value is used for TFTP's
2707 tftpdstport - If this is set, the value is used for TFTP's UDP
2708 destination port instead of the Well Know Port 69.
2710 vlan - When set to a value < 4095 the traffic over
2711 ethernet is encapsulated/received over 802.1q
2714 The following environment variables may be used and automatically
2715 updated by the network boot commands ("bootp" and "rarpboot"),
2716 depending the information provided by your boot server:
2718 bootfile - see above
2719 dnsip - IP address of your Domain Name Server
2720 dnsip2 - IP address of your secondary Domain Name Server
2721 gatewayip - IP address of the Gateway (Router) to use
2722 hostname - Target hostname
2724 netmask - Subnet Mask
2725 rootpath - Pathname of the root filesystem on the NFS server
2726 serverip - see above
2729 There are two special Environment Variables:
2731 serial# - contains hardware identification information such
2732 as type string and/or serial number
2733 ethaddr - Ethernet address
2735 These variables can be set only once (usually during manufacturing of
2736 the board). U-Boot refuses to delete or overwrite these variables
2737 once they have been set once.
2740 Further special Environment Variables:
2742 ver - Contains the U-Boot version string as printed
2743 with the "version" command. This variable is
2744 readonly (see CONFIG_VERSION_VARIABLE).
2747 Please note that changes to some configuration parameters may take
2748 only effect after the next boot (yes, that's just like Windoze :-).
2751 Command Line Parsing:
2752 =====================
2754 There are two different command line parsers available with U-Boot:
2755 the old "simple" one, and the much more powerful "hush" shell:
2757 Old, simple command line parser:
2758 --------------------------------
2760 - supports environment variables (through setenv / saveenv commands)
2761 - several commands on one line, separated by ';'
2762 - variable substitution using "... ${name} ..." syntax
2763 - special characters ('$', ';') can be escaped by prefixing with '\',
2765 setenv bootcmd bootm \${address}
2766 - You can also escape text by enclosing in single apostrophes, for example:
2767 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2772 - similar to Bourne shell, with control structures like
2773 if...then...else...fi, for...do...done; while...do...done,
2774 until...do...done, ...
2775 - supports environment ("global") variables (through setenv / saveenv
2776 commands) and local shell variables (through standard shell syntax
2777 "name=value"); only environment variables can be used with "run"
2783 (1) If a command line (or an environment variable executed by a "run"
2784 command) contains several commands separated by semicolon, and
2785 one of these commands fails, then the remaining commands will be
2788 (2) If you execute several variables with one call to run (i. e.
2789 calling run with a list af variables as arguments), any failing
2790 command will cause "run" to terminate, i. e. the remaining
2791 variables are not executed.
2793 Note for Redundant Ethernet Interfaces:
2794 =======================================
2796 Some boards come with redundant ethernet interfaces; U-Boot supports
2797 such configurations and is capable of automatic selection of a
2798 "working" interface when needed. MAC assignment works as follows:
2800 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2801 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2802 "eth1addr" (=>eth1), "eth2addr", ...
2804 If the network interface stores some valid MAC address (for instance
2805 in SROM), this is used as default address if there is NO correspon-
2806 ding setting in the environment; if the corresponding environment
2807 variable is set, this overrides the settings in the card; that means:
2809 o If the SROM has a valid MAC address, and there is no address in the
2810 environment, the SROM's address is used.
2812 o If there is no valid address in the SROM, and a definition in the
2813 environment exists, then the value from the environment variable is
2816 o If both the SROM and the environment contain a MAC address, and
2817 both addresses are the same, this MAC address is used.
2819 o If both the SROM and the environment contain a MAC address, and the
2820 addresses differ, the value from the environment is used and a
2823 o If neither SROM nor the environment contain a MAC address, an error
2830 The "boot" commands of this monitor operate on "image" files which
2831 can be basicly anything, preceeded by a special header; see the
2832 definitions in include/image.h for details; basicly, the header
2833 defines the following image properties:
2835 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2836 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2837 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2838 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2839 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2840 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2841 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2842 * Compression Type (uncompressed, gzip, bzip2)
2848 The header is marked by a special Magic Number, and both the header
2849 and the data portions of the image are secured against corruption by
2856 Although U-Boot should support any OS or standalone application
2857 easily, the main focus has always been on Linux during the design of
2860 U-Boot includes many features that so far have been part of some
2861 special "boot loader" code within the Linux kernel. Also, any
2862 "initrd" images to be used are no longer part of one big Linux image;
2863 instead, kernel and "initrd" are separate images. This implementation
2864 serves several purposes:
2866 - the same features can be used for other OS or standalone
2867 applications (for instance: using compressed images to reduce the
2868 Flash memory footprint)
2870 - it becomes much easier to port new Linux kernel versions because
2871 lots of low-level, hardware dependent stuff are done by U-Boot
2873 - the same Linux kernel image can now be used with different "initrd"
2874 images; of course this also means that different kernel images can
2875 be run with the same "initrd". This makes testing easier (you don't
2876 have to build a new "zImage.initrd" Linux image when you just
2877 change a file in your "initrd"). Also, a field-upgrade of the
2878 software is easier now.
2884 Porting Linux to U-Boot based systems:
2885 ---------------------------------------
2887 U-Boot cannot save you from doing all the necessary modifications to
2888 configure the Linux device drivers for use with your target hardware
2889 (no, we don't intend to provide a full virtual machine interface to
2892 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2894 Just make sure your machine specific header file (for instance
2895 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2896 Information structure as we define in include/u-boot.h, and make
2897 sure that your definition of IMAP_ADDR uses the same value as your
2898 U-Boot configuration in CFG_IMMR.
2901 Configuring the Linux kernel:
2902 -----------------------------
2904 No specific requirements for U-Boot. Make sure you have some root
2905 device (initial ramdisk, NFS) for your target system.
2908 Building a Linux Image:
2909 -----------------------
2911 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2912 not used. If you use recent kernel source, a new build target
2913 "uImage" will exist which automatically builds an image usable by
2914 U-Boot. Most older kernels also have support for a "pImage" target,
2915 which was introduced for our predecessor project PPCBoot and uses a
2916 100% compatible format.
2925 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2926 encapsulate a compressed Linux kernel image with header information,
2927 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2929 * build a standard "vmlinux" kernel image (in ELF binary format):
2931 * convert the kernel into a raw binary image:
2933 ${CROSS_COMPILE}-objcopy -O binary \
2934 -R .note -R .comment \
2935 -S vmlinux linux.bin
2937 * compress the binary image:
2941 * package compressed binary image for U-Boot:
2943 mkimage -A ppc -O linux -T kernel -C gzip \
2944 -a 0 -e 0 -n "Linux Kernel Image" \
2945 -d linux.bin.gz uImage
2948 The "mkimage" tool can also be used to create ramdisk images for use
2949 with U-Boot, either separated from the Linux kernel image, or
2950 combined into one file. "mkimage" encapsulates the images with a 64
2951 byte header containing information about target architecture,
2952 operating system, image type, compression method, entry points, time
2953 stamp, CRC32 checksums, etc.
2955 "mkimage" can be called in two ways: to verify existing images and
2956 print the header information, or to build new images.
2958 In the first form (with "-l" option) mkimage lists the information
2959 contained in the header of an existing U-Boot image; this includes
2960 checksum verification:
2962 tools/mkimage -l image
2963 -l ==> list image header information
2965 The second form (with "-d" option) is used to build a U-Boot image
2966 from a "data file" which is used as image payload:
2968 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2969 -n name -d data_file image
2970 -A ==> set architecture to 'arch'
2971 -O ==> set operating system to 'os'
2972 -T ==> set image type to 'type'
2973 -C ==> set compression type 'comp'
2974 -a ==> set load address to 'addr' (hex)
2975 -e ==> set entry point to 'ep' (hex)
2976 -n ==> set image name to 'name'
2977 -d ==> use image data from 'datafile'
2979 Right now, all Linux kernels for PowerPC systems use the same load
2980 address (0x00000000), but the entry point address depends on the
2983 - 2.2.x kernels have the entry point at 0x0000000C,
2984 - 2.3.x and later kernels have the entry point at 0x00000000.
2986 So a typical call to build a U-Boot image would read:
2988 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2989 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2990 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2991 > examples/uImage.TQM850L
2992 Image Name: 2.4.4 kernel for TQM850L
2993 Created: Wed Jul 19 02:34:59 2000
2994 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2995 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2996 Load Address: 0x00000000
2997 Entry Point: 0x00000000
2999 To verify the contents of the image (or check for corruption):
3001 -> tools/mkimage -l examples/uImage.TQM850L
3002 Image Name: 2.4.4 kernel for TQM850L
3003 Created: Wed Jul 19 02:34:59 2000
3004 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3005 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3006 Load Address: 0x00000000
3007 Entry Point: 0x00000000
3009 NOTE: for embedded systems where boot time is critical you can trade
3010 speed for memory and install an UNCOMPRESSED image instead: this
3011 needs more space in Flash, but boots much faster since it does not
3012 need to be uncompressed:
3014 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3015 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3016 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3017 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3018 > examples/uImage.TQM850L-uncompressed
3019 Image Name: 2.4.4 kernel for TQM850L
3020 Created: Wed Jul 19 02:34:59 2000
3021 Image Type: PowerPC Linux Kernel Image (uncompressed)
3022 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3023 Load Address: 0x00000000
3024 Entry Point: 0x00000000
3027 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3028 when your kernel is intended to use an initial ramdisk:
3030 -> tools/mkimage -n 'Simple Ramdisk Image' \
3031 > -A ppc -O linux -T ramdisk -C gzip \
3032 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3033 Image Name: Simple Ramdisk Image
3034 Created: Wed Jan 12 14:01:50 2000
3035 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3036 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3037 Load Address: 0x00000000
3038 Entry Point: 0x00000000
3041 Installing a Linux Image:
3042 -------------------------
3044 To downloading a U-Boot image over the serial (console) interface,
3045 you must convert the image to S-Record format:
3047 objcopy -I binary -O srec examples/image examples/image.srec
3049 The 'objcopy' does not understand the information in the U-Boot
3050 image header, so the resulting S-Record file will be relative to
3051 address 0x00000000. To load it to a given address, you need to
3052 specify the target address as 'offset' parameter with the 'loads'
3055 Example: install the image to address 0x40100000 (which on the
3056 TQM8xxL is in the first Flash bank):
3058 => erase 40100000 401FFFFF
3064 ## Ready for S-Record download ...
3065 ~>examples/image.srec
3066 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3068 15989 15990 15991 15992
3069 [file transfer complete]
3071 ## Start Addr = 0x00000000
3074 You can check the success of the download using the 'iminfo' command;
3075 this includes a checksum verification so you can be sure no data
3076 corruption happened:
3080 ## Checking Image at 40100000 ...
3081 Image Name: 2.2.13 for initrd on TQM850L
3082 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3083 Data Size: 335725 Bytes = 327 kB = 0 MB
3084 Load Address: 00000000
3085 Entry Point: 0000000c
3086 Verifying Checksum ... OK
3092 The "bootm" command is used to boot an application that is stored in
3093 memory (RAM or Flash). In case of a Linux kernel image, the contents
3094 of the "bootargs" environment variable is passed to the kernel as
3095 parameters. You can check and modify this variable using the
3096 "printenv" and "setenv" commands:
3099 => printenv bootargs
3100 bootargs=root=/dev/ram
3102 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3104 => printenv bootargs
3105 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3108 ## Booting Linux kernel at 40020000 ...
3109 Image Name: 2.2.13 for NFS on TQM850L
3110 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3111 Data Size: 381681 Bytes = 372 kB = 0 MB
3112 Load Address: 00000000
3113 Entry Point: 0000000c
3114 Verifying Checksum ... OK
3115 Uncompressing Kernel Image ... OK
3116 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
3117 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3118 time_init: decrementer frequency = 187500000/60
3119 Calibrating delay loop... 49.77 BogoMIPS
3120 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3123 If you want to boot a Linux kernel with initial ram disk, you pass
3124 the memory addresses of both the kernel and the initrd image (PPBCOOT
3125 format!) to the "bootm" command:
3127 => imi 40100000 40200000
3129 ## Checking Image at 40100000 ...
3130 Image Name: 2.2.13 for initrd on TQM850L
3131 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3132 Data Size: 335725 Bytes = 327 kB = 0 MB
3133 Load Address: 00000000
3134 Entry Point: 0000000c
3135 Verifying Checksum ... OK
3137 ## Checking Image at 40200000 ...
3138 Image Name: Simple Ramdisk Image
3139 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3140 Data Size: 566530 Bytes = 553 kB = 0 MB
3141 Load Address: 00000000
3142 Entry Point: 00000000
3143 Verifying Checksum ... OK
3145 => bootm 40100000 40200000
3146 ## Booting Linux kernel at 40100000 ...
3147 Image Name: 2.2.13 for initrd on TQM850L
3148 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3149 Data Size: 335725 Bytes = 327 kB = 0 MB
3150 Load Address: 00000000
3151 Entry Point: 0000000c
3152 Verifying Checksum ... OK
3153 Uncompressing Kernel Image ... OK
3154 ## Loading RAMDisk Image at 40200000 ...
3155 Image Name: Simple Ramdisk Image
3156 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3157 Data Size: 566530 Bytes = 553 kB = 0 MB
3158 Load Address: 00000000
3159 Entry Point: 00000000
3160 Verifying Checksum ... OK
3161 Loading Ramdisk ... OK
3162 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
3163 Boot arguments: root=/dev/ram
3164 time_init: decrementer frequency = 187500000/60
3165 Calibrating delay loop... 49.77 BogoMIPS
3167 RAMDISK: Compressed image found at block 0
3168 VFS: Mounted root (ext2 filesystem).
3172 Boot Linux and pass a flat device tree:
3175 First, U-Boot must be compiled with the appropriate defines. See the section
3176 titled "Linux Kernel Interface" above for a more in depth explanation. The
3177 following is an example of how to start a kernel and pass an updated
3183 oft=oftrees/mpc8540ads.dtb
3184 => tftp $oftaddr $oft
3185 Speed: 1000, full duplex
3187 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3188 Filename 'oftrees/mpc8540ads.dtb'.
3189 Load address: 0x300000
3192 Bytes transferred = 4106 (100a hex)
3193 => tftp $loadaddr $bootfile
3194 Speed: 1000, full duplex
3196 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3198 Load address: 0x200000
3199 Loading:############
3201 Bytes transferred = 1029407 (fb51f hex)
3206 => bootm $loadaddr - $oftaddr
3207 ## Booting image at 00200000 ...
3208 Image Name: Linux-2.6.17-dirty
3209 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3210 Data Size: 1029343 Bytes = 1005.2 kB
3211 Load Address: 00000000
3212 Entry Point: 00000000
3213 Verifying Checksum ... OK
3214 Uncompressing Kernel Image ... OK
3215 Booting using flat device tree at 0x300000
3216 Using MPC85xx ADS machine description
3217 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3221 More About U-Boot Image Types:
3222 ------------------------------
3224 U-Boot supports the following image types:
3226 "Standalone Programs" are directly runnable in the environment
3227 provided by U-Boot; it is expected that (if they behave
3228 well) you can continue to work in U-Boot after return from
3229 the Standalone Program.
3230 "OS Kernel Images" are usually images of some Embedded OS which
3231 will take over control completely. Usually these programs
3232 will install their own set of exception handlers, device
3233 drivers, set up the MMU, etc. - this means, that you cannot
3234 expect to re-enter U-Boot except by resetting the CPU.
3235 "RAMDisk Images" are more or less just data blocks, and their
3236 parameters (address, size) are passed to an OS kernel that is
3238 "Multi-File Images" contain several images, typically an OS
3239 (Linux) kernel image and one or more data images like
3240 RAMDisks. This construct is useful for instance when you want
3241 to boot over the network using BOOTP etc., where the boot
3242 server provides just a single image file, but you want to get
3243 for instance an OS kernel and a RAMDisk image.
3245 "Multi-File Images" start with a list of image sizes, each
3246 image size (in bytes) specified by an "uint32_t" in network
3247 byte order. This list is terminated by an "(uint32_t)0".
3248 Immediately after the terminating 0 follow the images, one by
3249 one, all aligned on "uint32_t" boundaries (size rounded up to
3250 a multiple of 4 bytes).
3252 "Firmware Images" are binary images containing firmware (like
3253 U-Boot or FPGA images) which usually will be programmed to
3256 "Script files" are command sequences that will be executed by
3257 U-Boot's command interpreter; this feature is especially
3258 useful when you configure U-Boot to use a real shell (hush)
3259 as command interpreter.
3265 One of the features of U-Boot is that you can dynamically load and
3266 run "standalone" applications, which can use some resources of
3267 U-Boot like console I/O functions or interrupt services.
3269 Two simple examples are included with the sources:
3274 'examples/hello_world.c' contains a small "Hello World" Demo
3275 application; it is automatically compiled when you build U-Boot.
3276 It's configured to run at address 0x00040004, so you can play with it
3280 ## Ready for S-Record download ...
3281 ~>examples/hello_world.srec
3282 1 2 3 4 5 6 7 8 9 10 11 ...
3283 [file transfer complete]
3285 ## Start Addr = 0x00040004
3287 => go 40004 Hello World! This is a test.
3288 ## Starting application at 0x00040004 ...
3299 Hit any key to exit ...
3301 ## Application terminated, rc = 0x0
3303 Another example, which demonstrates how to register a CPM interrupt
3304 handler with the U-Boot code, can be found in 'examples/timer.c'.
3305 Here, a CPM timer is set up to generate an interrupt every second.
3306 The interrupt service routine is trivial, just printing a '.'
3307 character, but this is just a demo program. The application can be
3308 controlled by the following keys:
3310 ? - print current values og the CPM Timer registers
3311 b - enable interrupts and start timer
3312 e - stop timer and disable interrupts
3313 q - quit application
3316 ## Ready for S-Record download ...
3317 ~>examples/timer.srec
3318 1 2 3 4 5 6 7 8 9 10 11 ...
3319 [file transfer complete]
3321 ## Start Addr = 0x00040004
3324 ## Starting application at 0x00040004 ...
3327 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3330 [q, b, e, ?] Set interval 1000000 us
3333 [q, b, e, ?] ........
3334 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3337 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3340 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3343 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3345 [q, b, e, ?] ...Stopping timer
3347 [q, b, e, ?] ## Application terminated, rc = 0x0
3353 Over time, many people have reported problems when trying to use the
3354 "minicom" terminal emulation program for serial download. I (wd)
3355 consider minicom to be broken, and recommend not to use it. Under
3356 Unix, I recommend to use C-Kermit for general purpose use (and
3357 especially for kermit binary protocol download ("loadb" command), and
3358 use "cu" for S-Record download ("loads" command).
3360 Nevertheless, if you absolutely want to use it try adding this
3361 configuration to your "File transfer protocols" section:
3363 Name Program Name U/D FullScr IO-Red. Multi
3364 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3365 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3371 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3372 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3374 Building requires a cross environment; it is known to work on
3375 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3376 need gmake since the Makefiles are not compatible with BSD make).
3377 Note that the cross-powerpc package does not install include files;
3378 attempting to build U-Boot will fail because <machine/ansi.h> is
3379 missing. This file has to be installed and patched manually:
3381 # cd /usr/pkg/cross/powerpc-netbsd/include
3383 # ln -s powerpc machine
3384 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3385 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3387 Native builds *don't* work due to incompatibilities between native
3388 and U-Boot include files.
3390 Booting assumes that (the first part of) the image booted is a
3391 stage-2 loader which in turn loads and then invokes the kernel
3392 proper. Loader sources will eventually appear in the NetBSD source
3393 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3394 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3397 Implementation Internals:
3398 =========================
3400 The following is not intended to be a complete description of every
3401 implementation detail. However, it should help to understand the
3402 inner workings of U-Boot and make it easier to port it to custom
3406 Initial Stack, Global Data:
3407 ---------------------------
3409 The implementation of U-Boot is complicated by the fact that U-Boot
3410 starts running out of ROM (flash memory), usually without access to
3411 system RAM (because the memory controller is not initialized yet).
3412 This means that we don't have writable Data or BSS segments, and BSS
3413 is not initialized as zero. To be able to get a C environment working
3414 at all, we have to allocate at least a minimal stack. Implementation
3415 options for this are defined and restricted by the CPU used: Some CPU
3416 models provide on-chip memory (like the IMMR area on MPC8xx and
3417 MPC826x processors), on others (parts of) the data cache can be
3418 locked as (mis-) used as memory, etc.
3420 Chris Hallinan posted a good summary of these issues to the
3421 u-boot-users mailing list:
3423 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3424 From: "Chris Hallinan" <clh@net1plus.com>
3425 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3428 Correct me if I'm wrong, folks, but the way I understand it
3429 is this: Using DCACHE as initial RAM for Stack, etc, does not
3430 require any physical RAM backing up the cache. The cleverness
3431 is that the cache is being used as a temporary supply of
3432 necessary storage before the SDRAM controller is setup. It's
3433 beyond the scope of this list to expain the details, but you
3434 can see how this works by studying the cache architecture and
3435 operation in the architecture and processor-specific manuals.
3437 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3438 is another option for the system designer to use as an
3439 initial stack/ram area prior to SDRAM being available. Either
3440 option should work for you. Using CS 4 should be fine if your
3441 board designers haven't used it for something that would
3442 cause you grief during the initial boot! It is frequently not
3445 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3446 with your processor/board/system design. The default value
3447 you will find in any recent u-boot distribution in
3448 walnut.h should work for you. I'd set it to a value larger
3449 than your SDRAM module. If you have a 64MB SDRAM module, set
3450 it above 400_0000. Just make sure your board has no resources
3451 that are supposed to respond to that address! That code in
3452 start.S has been around a while and should work as is when
3453 you get the config right.
3458 It is essential to remember this, since it has some impact on the C
3459 code for the initialization procedures:
3461 * Initialized global data (data segment) is read-only. Do not attempt
3464 * Do not use any unitialized global data (or implicitely initialized
3465 as zero data - BSS segment) at all - this is undefined, initiali-
3466 zation is performed later (when relocating to RAM).
3468 * Stack space is very limited. Avoid big data buffers or things like
3471 Having only the stack as writable memory limits means we cannot use
3472 normal global data to share information beween the code. But it
3473 turned out that the implementation of U-Boot can be greatly
3474 simplified by making a global data structure (gd_t) available to all
3475 functions. We could pass a pointer to this data as argument to _all_
3476 functions, but this would bloat the code. Instead we use a feature of
3477 the GCC compiler (Global Register Variables) to share the data: we
3478 place a pointer (gd) to the global data into a register which we
3479 reserve for this purpose.
3481 When choosing a register for such a purpose we are restricted by the
3482 relevant (E)ABI specifications for the current architecture, and by
3483 GCC's implementation.
3485 For PowerPC, the following registers have specific use:
3488 R3-R4: parameter passing and return values
3489 R5-R10: parameter passing
3490 R13: small data area pointer
3494 (U-Boot also uses R14 as internal GOT pointer.)
3496 ==> U-Boot will use R29 to hold a pointer to the global data
3498 Note: on PPC, we could use a static initializer (since the
3499 address of the global data structure is known at compile time),
3500 but it turned out that reserving a register results in somewhat
3501 smaller code - although the code savings are not that big (on
3502 average for all boards 752 bytes for the whole U-Boot image,
3503 624 text + 127 data).
3505 On ARM, the following registers are used:
3507 R0: function argument word/integer result
3508 R1-R3: function argument word
3510 R10: stack limit (used only if stack checking if enabled)
3511 R11: argument (frame) pointer
3512 R12: temporary workspace
3515 R15: program counter
3517 ==> U-Boot will use R8 to hold a pointer to the global data
3519 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3520 or current versions of GCC may "optimize" the code too much.
3525 U-Boot runs in system state and uses physical addresses, i.e. the
3526 MMU is not used either for address mapping nor for memory protection.
3528 The available memory is mapped to fixed addresses using the memory
3529 controller. In this process, a contiguous block is formed for each
3530 memory type (Flash, SDRAM, SRAM), even when it consists of several
3531 physical memory banks.
3533 U-Boot is installed in the first 128 kB of the first Flash bank (on
3534 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3535 booting and sizing and initializing DRAM, the code relocates itself
3536 to the upper end of DRAM. Immediately below the U-Boot code some
3537 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3538 configuration setting]. Below that, a structure with global Board
3539 Info data is placed, followed by the stack (growing downward).
3541 Additionally, some exception handler code is copied to the low 8 kB
3542 of DRAM (0x00000000 ... 0x00001FFF).
3544 So a typical memory configuration with 16 MB of DRAM could look like
3547 0x0000 0000 Exception Vector code
3550 0x0000 2000 Free for Application Use
3556 0x00FB FF20 Monitor Stack (Growing downward)
3557 0x00FB FFAC Board Info Data and permanent copy of global data
3558 0x00FC 0000 Malloc Arena
3561 0x00FE 0000 RAM Copy of Monitor Code
3562 ... eventually: LCD or video framebuffer
3563 ... eventually: pRAM (Protected RAM - unchanged by reset)
3564 0x00FF FFFF [End of RAM]
3567 System Initialization:
3568 ----------------------
3570 In the reset configuration, U-Boot starts at the reset entry point
3571 (on most PowerPC systens at address 0x00000100). Because of the reset
3572 configuration for CS0# this is a mirror of the onboard Flash memory.
3573 To be able to re-map memory U-Boot then jumps to its link address.
3574 To be able to implement the initialization code in C, a (small!)
3575 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3576 which provide such a feature like MPC8xx or MPC8260), or in a locked
3577 part of the data cache. After that, U-Boot initializes the CPU core,
3578 the caches and the SIU.
3580 Next, all (potentially) available memory banks are mapped using a
3581 preliminary mapping. For example, we put them on 512 MB boundaries
3582 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3583 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3584 programmed for SDRAM access. Using the temporary configuration, a
3585 simple memory test is run that determines the size of the SDRAM
3588 When there is more than one SDRAM bank, and the banks are of
3589 different size, the largest is mapped first. For equal size, the first
3590 bank (CS2#) is mapped first. The first mapping is always for address
3591 0x00000000, with any additional banks following immediately to create
3592 contiguous memory starting from 0.
3594 Then, the monitor installs itself at the upper end of the SDRAM area
3595 and allocates memory for use by malloc() and for the global Board
3596 Info data; also, the exception vector code is copied to the low RAM
3597 pages, and the final stack is set up.
3599 Only after this relocation will you have a "normal" C environment;
3600 until that you are restricted in several ways, mostly because you are
3601 running from ROM, and because the code will have to be relocated to a
3605 U-Boot Porting Guide:
3606 ----------------------
3608 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3612 int main (int argc, char *argv[])
3614 sighandler_t no_more_time;
3616 signal (SIGALRM, no_more_time);
3617 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3619 if (available_money > available_manpower) {
3620 pay consultant to port U-Boot;
3624 Download latest U-Boot source;
3626 Subscribe to u-boot-users mailing list;
3629 email ("Hi, I am new to U-Boot, how do I get started?");
3633 Read the README file in the top level directory;
3634 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3635 Read the source, Luke;
3638 if (available_money > toLocalCurrency ($2500)) {
3641 Add a lot of aggravation and time;
3644 Create your own board support subdirectory;
3646 Create your own board config file;
3650 Add / modify source code;
3654 email ("Hi, I am having problems...");
3656 Send patch file to Wolfgang;
3661 void no_more_time (int sig)
3670 All contributions to U-Boot should conform to the Linux kernel
3671 coding style; see the file "Documentation/CodingStyle" and the script
3672 "scripts/Lindent" in your Linux kernel source directory. In sources
3673 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3674 spaces before parameters to function calls) is actually used.
3676 Source files originating from a different project (for example the
3677 MTD subsystem) are generally exempt from these guidelines and are not
3678 reformated to ease subsequent migration to newer versions of those
3681 Please note that U-Boot is implemented in C (and to some small parts in
3682 Assembler); no C++ is used, so please do not use C++ style comments (//)
3685 Please also stick to the following formatting rules:
3686 - remove any trailing white space
3687 - use TAB characters for indentation, not spaces
3688 - make sure NOT to use DOS '\r\n' line feeds
3689 - do not add more than 2 empty lines to source files
3690 - do not add trailing empty lines to source files
3692 Submissions which do not conform to the standards may be returned
3693 with a request to reformat the changes.
3699 Since the number of patches for U-Boot is growing, we need to
3700 establish some rules. Submissions which do not conform to these rules
3701 may be rejected, even when they contain important and valuable stuff.
3703 Patches shall be sent to the u-boot-users mailing list.
3705 When you send a patch, please include the following information with
3708 * For bug fixes: a description of the bug and how your patch fixes
3709 this bug. Please try to include a way of demonstrating that the
3710 patch actually fixes something.
3712 * For new features: a description of the feature and your
3715 * A CHANGELOG entry as plaintext (separate from the patch)
3717 * For major contributions, your entry to the CREDITS file
3719 * When you add support for a new board, don't forget to add this
3720 board to the MAKEALL script, too.
3722 * If your patch adds new configuration options, don't forget to
3723 document these in the README file.
3725 * The patch itself. If you are accessing the CVS repository use "cvs
3726 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3727 version of diff does not support these options, then get the latest
3728 version of GNU diff.
3730 The current directory when running this command shall be the top
3731 level directory of the U-Boot source tree, or it's parent directory
3732 (i. e. please make sure that your patch includes sufficient
3733 directory information for the affected files).
3735 We accept patches as plain text, MIME attachments or as uuencoded
3738 * If one logical set of modifications affects or creates several
3739 files, all these changes shall be submitted in a SINGLE patch file.
3741 * Changesets that contain different, unrelated modifications shall be
3742 submitted as SEPARATE patches, one patch per changeset.
3747 * Before sending the patch, run the MAKEALL script on your patched
3748 source tree and make sure that no errors or warnings are reported
3749 for any of the boards.
3751 * Keep your modifications to the necessary minimum: A patch
3752 containing several unrelated changes or arbitrary reformats will be
3753 returned with a request to re-formatting / split it.
3755 * If you modify existing code, make sure that your new code does not
3756 add to the memory footprint of the code ;-) Small is beautiful!
3757 When adding new features, these should compile conditionally only
3758 (using #ifdef), and the resulting code with the new feature
3759 disabled must not need more memory than the old code without your
3762 * Remember that there is a size limit of 40 kB per message on the
3763 u-boot-users mailing list. Compression may help.
projects / karo-tx-uboot.git / blob