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 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
140 - mips Files specific to MIPS CPUs
141 - mpc5xx Files specific to Freescale MPC5xx CPUs
142 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
143 - mpc8xx Files specific to Freescale MPC8xx CPUs
144 - mpc8220 Files specific to Freescale MPC8220 CPUs
145 - mpc824x Files specific to Freescale MPC824x CPUs
146 - mpc8260 Files specific to Freescale MPC8260 CPUs
147 - mpc85xx Files specific to Freescale MPC85xx CPUs
148 - nios Files specific to Altera NIOS CPUs
149 - nios2 Files specific to Altera Nios-II CPUs
150 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
151 - pxa Files specific to Intel XScale PXA CPUs
152 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
153 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
154 - disk Code for disk drive partition handling
155 - doc Documentation (don't expect too much)
156 - drivers Commonly used device drivers
157 - dtt Digital Thermometer and Thermostat drivers
158 - examples Example code for standalone applications, etc.
159 - include Header Files
160 - lib_arm Files generic to ARM architecture
161 - lib_avr32 Files generic to AVR32 architecture
162 - lib_generic Files generic to all architectures
163 - lib_i386 Files generic to i386 architecture
164 - lib_m68k Files generic to m68k architecture
165 - lib_mips Files generic to MIPS architecture
166 - lib_nios Files generic to NIOS architecture
167 - lib_ppc Files generic to PowerPC architecture
168 - libfdt Library files to support flattened device trees
169 - net Networking code
170 - post Power On Self Test
171 - rtc Real Time Clock drivers
172 - tools Tools to build S-Record or U-Boot images, etc.
174 Software Configuration:
175 =======================
177 Configuration is usually done using C preprocessor defines; the
178 rationale behind that is to avoid dead code whenever possible.
180 There are two classes of configuration variables:
182 * Configuration _OPTIONS_:
183 These are selectable by the user and have names beginning with
186 * Configuration _SETTINGS_:
187 These depend on the hardware etc. and should not be meddled with if
188 you don't know what you're doing; they have names beginning with
191 Later we will add a configuration tool - probably similar to or even
192 identical to what's used for the Linux kernel. Right now, we have to
193 do the configuration by hand, which means creating some symbolic
194 links and editing some configuration files. We use the TQM8xxL boards
198 Selection of Processor Architecture and Board Type:
199 ---------------------------------------------------
201 For all supported boards there are ready-to-use default
202 configurations available; just type "make <board_name>_config".
204 Example: For a TQM823L module type:
209 For the Cogent platform, you need to specify the cpu type as well;
210 e.g. "make cogent_mpc8xx_config". And also configure the cogent
211 directory according to the instructions in cogent/README.
214 Configuration Options:
215 ----------------------
217 Configuration depends on the combination of board and CPU type; all
218 such information is kept in a configuration file
219 "include/configs/<board_name>.h".
221 Example: For a TQM823L module, all configuration settings are in
222 "include/configs/TQM823L.h".
225 Many of the options are named exactly as the corresponding Linux
226 kernel configuration options. The intention is to make it easier to
227 build a config tool - later.
230 The following options need to be configured:
232 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
234 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
236 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
237 Define exactly one of
241 - CPU Module Type: (if CONFIG_COGENT is defined)
242 Define exactly one of
244 --- FIXME --- not tested yet:
245 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
246 CONFIG_CMA287_23, CONFIG_CMA287_50
248 - Motherboard Type: (if CONFIG_COGENT is defined)
249 Define exactly one of
250 CONFIG_CMA101, CONFIG_CMA102
252 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
253 Define one or more of
256 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
257 Define one or more of
258 CONFIG_LCD_HEARTBEAT - update a character position on
259 the lcd display every second with
262 - Board flavour: (if CONFIG_MPC8260ADS is defined)
265 CFG_8260ADS - original MPC8260ADS
266 CFG_8266ADS - MPC8266ADS
267 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
268 CFG_8272ADS - MPC8272ADS
270 - MPC824X Family Member (if CONFIG_MPC824X is defined)
271 Define exactly one of
272 CONFIG_MPC8240, CONFIG_MPC8245
274 - 8xx CPU Options: (if using an MPC8xx cpu)
275 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
276 get_gclk_freq() cannot work
277 e.g. if there is no 32KHz
278 reference PIT/RTC clock
279 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
282 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
285 CONFIG_8xx_CPUCLK_DEFAULT
286 See doc/README.MPC866
290 Define this to measure the actual CPU clock instead
291 of relying on the correctness of the configured
292 values. Mostly useful for board bringup to make sure
293 the PLL is locked at the intended frequency. Note
294 that this requires a (stable) reference clock (32 kHz
295 RTC clock or CFG_8XX_XIN)
297 - Intel Monahans options:
298 CFG_MONAHANS_RUN_MODE_OSC_RATIO
300 Defines the Monahans run mode to oscillator
301 ratio. Valid values are 8, 16, 24, 31. The core
302 frequency is this value multiplied by 13 MHz.
304 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
306 Defines the Monahans turbo mode to oscillator
307 ratio. Valid values are 1 (default if undefined) and
308 2. The core frequency as calculated above is multiplied
311 - Linux Kernel Interface:
314 U-Boot stores all clock information in Hz
315 internally. For binary compatibility with older Linux
316 kernels (which expect the clocks passed in the
317 bd_info data to be in MHz) the environment variable
318 "clocks_in_mhz" can be defined so that U-Boot
319 converts clock data to MHZ before passing it to the
321 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
322 "clocks_in_mhz=1" is automatically included in the
325 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
327 When transfering memsize parameter to linux, some versions
328 expect it to be in bytes, others in MB.
329 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
331 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
333 New kernel versions are expecting firmware settings to be
334 passed using flattened device trees (based on open firmware
338 * New libfdt-based support
339 * Adds the "fdt" command
340 * The bootm command does _not_ modify the fdt
343 * Deprecated, see CONFIG_OF_LIBFDT
344 * Original ft_build.c-based support
345 * Automatically modifies the dft as part of the bootm command
346 * The environment variable "disable_of", when set,
347 disables this functionality.
349 CONFIG_OF_FLAT_TREE_MAX_SIZE
351 The maximum size of the constructed OF tree.
353 OF_CPU - The proper name of the cpus node.
354 OF_SOC - The proper name of the soc node.
355 OF_TBCLK - The timebase frequency.
356 OF_STDOUT_PATH - The path to the console device
360 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
361 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
362 will have a copy of the bd_t. Space should be
363 pre-allocated in the dts for the bd_t.
365 CONFIG_OF_HAS_UBOOT_ENV
367 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
368 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
369 will have a copy of u-boot's environment variables
371 CONFIG_OF_BOARD_SETUP
373 Board code has addition modification that it wants to make
374 to the flat device tree before handing it off to the kernel
378 This define fills in the correct boot cpu in the boot
379 param header, the default value is zero if undefined.
384 Define this if you want support for Amba PrimeCell PL010 UARTs.
388 Define this if you want support for Amba PrimeCell PL011 UARTs.
392 If you have Amba PrimeCell PL011 UARTs, set this variable to
393 the clock speed of the UARTs.
397 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
398 define this to a list of base addresses for each (supported)
399 port. See e.g. include/configs/versatile.h
403 Depending on board, define exactly one serial port
404 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
405 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
406 console by defining CONFIG_8xx_CONS_NONE
408 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
409 port routines must be defined elsewhere
410 (i.e. serial_init(), serial_getc(), ...)
413 Enables console device for a color framebuffer. Needs following
414 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
415 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
417 VIDEO_HW_RECTFILL graphic chip supports
420 VIDEO_HW_BITBLT graphic chip supports
421 bit-blit (cf. smiLynxEM)
422 VIDEO_VISIBLE_COLS visible pixel columns
424 VIDEO_VISIBLE_ROWS visible pixel rows
425 VIDEO_PIXEL_SIZE bytes per pixel
426 VIDEO_DATA_FORMAT graphic data format
427 (0-5, cf. cfb_console.c)
428 VIDEO_FB_ADRS framebuffer address
429 VIDEO_KBD_INIT_FCT keyboard int fct
430 (i.e. i8042_kbd_init())
431 VIDEO_TSTC_FCT test char fct
433 VIDEO_GETC_FCT get char fct
435 CONFIG_CONSOLE_CURSOR cursor drawing on/off
436 (requires blink timer
438 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
439 CONFIG_CONSOLE_TIME display time/date info in
441 (requires CONFIG_CMD_DATE)
442 CONFIG_VIDEO_LOGO display Linux logo in
444 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
445 linux_logo.h for logo.
446 Requires CONFIG_VIDEO_LOGO
447 CONFIG_CONSOLE_EXTRA_INFO
448 addional board info beside
451 When CONFIG_CFB_CONSOLE is defined, video console is
452 default i/o. Serial console can be forced with
453 environment 'console=serial'.
455 When CONFIG_SILENT_CONSOLE is defined, all console
456 messages (by U-Boot and Linux!) can be silenced with
457 the "silent" environment variable. See
458 doc/README.silent for more information.
461 CONFIG_BAUDRATE - in bps
462 Select one of the baudrates listed in
463 CFG_BAUDRATE_TABLE, see below.
464 CFG_BRGCLK_PRESCALE, baudrate prescale
466 - Interrupt driven serial port input:
467 CONFIG_SERIAL_SOFTWARE_FIFO
470 Use an interrupt handler for receiving data on the
471 serial port. It also enables using hardware handshake
472 (RTS/CTS) and UART's built-in FIFO. Set the number of
473 bytes the interrupt driven input buffer should have.
475 Leave undefined to disable this feature, including
476 disable the buffer and hardware handshake.
478 - Console UART Number:
482 If defined internal UART1 (and not UART0) is used
483 as default U-Boot console.
485 - Boot Delay: CONFIG_BOOTDELAY - in seconds
486 Delay before automatically booting the default image;
487 set to -1 to disable autoboot.
489 See doc/README.autoboot for these options that
490 work with CONFIG_BOOTDELAY. None are required.
491 CONFIG_BOOT_RETRY_TIME
492 CONFIG_BOOT_RETRY_MIN
493 CONFIG_AUTOBOOT_KEYED
494 CONFIG_AUTOBOOT_PROMPT
495 CONFIG_AUTOBOOT_DELAY_STR
496 CONFIG_AUTOBOOT_STOP_STR
497 CONFIG_AUTOBOOT_DELAY_STR2
498 CONFIG_AUTOBOOT_STOP_STR2
499 CONFIG_ZERO_BOOTDELAY_CHECK
500 CONFIG_RESET_TO_RETRY
504 Only needed when CONFIG_BOOTDELAY is enabled;
505 define a command string that is automatically executed
506 when no character is read on the console interface
507 within "Boot Delay" after reset.
510 This can be used to pass arguments to the bootm
511 command. The value of CONFIG_BOOTARGS goes into the
512 environment value "bootargs".
514 CONFIG_RAMBOOT and CONFIG_NFSBOOT
515 The value of these goes into the environment as
516 "ramboot" and "nfsboot" respectively, and can be used
517 as a convenience, when switching between booting from
523 When this option is #defined, the existence of the
524 environment variable "preboot" will be checked
525 immediately before starting the CONFIG_BOOTDELAY
526 countdown and/or running the auto-boot command resp.
527 entering interactive mode.
529 This feature is especially useful when "preboot" is
530 automatically generated or modified. For an example
531 see the LWMON board specific code: here "preboot" is
532 modified when the user holds down a certain
533 combination of keys on the (special) keyboard when
536 - Serial Download Echo Mode:
538 If defined to 1, all characters received during a
539 serial download (using the "loads" command) are
540 echoed back. This might be needed by some terminal
541 emulations (like "cu"), but may as well just take
542 time on others. This setting #define's the initial
543 value of the "loads_echo" environment variable.
545 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
547 Select one of the baudrates listed in
548 CFG_BAUDRATE_TABLE, see below.
551 Monitor commands can be included or excluded
552 from the build by using the #include files
553 "config_cmd_all.h" and #undef'ing unwanted
554 commands, or using "config_cmd_default.h"
555 and augmenting with additional #define's
558 The default command configuration includes all commands
559 except those marked below with a "*".
561 CONFIG_CMD_ASKENV * ask for env variable
562 CONFIG_CMD_AUTOSCRIPT Autoscript Support
563 CONFIG_CMD_BDI bdinfo
564 CONFIG_CMD_BEDBUG * Include BedBug Debugger
565 CONFIG_CMD_BMP * BMP support
566 CONFIG_CMD_BSP * Board specific commands
567 CONFIG_CMD_BOOTD bootd
568 CONFIG_CMD_CACHE * icache, dcache
569 CONFIG_CMD_CONSOLE coninfo
570 CONFIG_CMD_DATE * support for RTC, date/time...
571 CONFIG_CMD_DHCP * DHCP support
572 CONFIG_CMD_DIAG * Diagnostics
573 CONFIG_CMD_DOC * Disk-On-Chip Support
574 CONFIG_CMD_DTT * Digital Therm and Thermostat
575 CONFIG_CMD_ECHO echo arguments
576 CONFIG_CMD_EEPROM * EEPROM read/write support
577 CONFIG_CMD_ELF * bootelf, bootvx
578 CONFIG_CMD_ENV saveenv
579 CONFIG_CMD_FDC * Floppy Disk Support
580 CONFIG_CMD_FAT * FAT partition support
581 CONFIG_CMD_FDOS * Dos diskette Support
582 CONFIG_CMD_FLASH flinfo, erase, protect
583 CONFIG_CMD_FPGA FPGA device initialization support
584 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
585 CONFIG_CMD_I2C * I2C serial bus support
586 CONFIG_CMD_IDE * IDE harddisk support
587 CONFIG_CMD_IMI iminfo
588 CONFIG_CMD_IMLS List all found images
589 CONFIG_CMD_IMMAP * IMMR dump support
590 CONFIG_CMD_IRQ * irqinfo
591 CONFIG_CMD_ITEST Integer/string test of 2 values
592 CONFIG_CMD_JFFS2 * JFFS2 Support
593 CONFIG_CMD_KGDB * kgdb
594 CONFIG_CMD_LOADB loadb
595 CONFIG_CMD_LOADS loads
596 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
598 CONFIG_CMD_MISC Misc functions like sleep etc
599 CONFIG_CMD_MMC * MMC memory mapped support
600 CONFIG_CMD_MII * MII utility commands
601 CONFIG_CMD_NAND * NAND support
602 CONFIG_CMD_NET bootp, tftpboot, rarpboot
603 CONFIG_CMD_PCI * pciinfo
604 CONFIG_CMD_PCMCIA * PCMCIA support
605 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
607 CONFIG_CMD_PORTIO * Port I/O
608 CONFIG_CMD_REGINFO * Register dump
609 CONFIG_CMD_RUN run command in env variable
610 CONFIG_CMD_SAVES * save S record dump
611 CONFIG_CMD_SCSI * SCSI Support
612 CONFIG_CMD_SDRAM * print SDRAM configuration information
613 (requires CONFIG_CMD_I2C)
614 CONFIG_CMD_SETGETDCR Support for DCR Register access
616 CONFIG_CMD_SPI * SPI serial bus support
617 CONFIG_CMD_USB * USB support
618 CONFIG_CMD_VFD * VFD support (TRAB)
619 CONFIG_CMD_BSP * Board SPecific functions
620 CONFIG_CMD_CDP * Cisco Discover Protocol support
621 CONFIG_CMD_FSL * Microblaze FSL support
624 EXAMPLE: If you want all functions except of network
625 support you can write:
627 #include "config_cmd_all.h"
628 #undef CONFIG_CMD_NET
631 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
633 Note: Don't enable the "icache" and "dcache" commands
634 (configuration option CONFIG_CMD_CACHE) unless you know
635 what you (and your U-Boot users) are doing. Data
636 cache cannot be enabled on systems like the 8xx or
637 8260 (where accesses to the IMMR region must be
638 uncached), and it cannot be disabled on all other
639 systems where we (mis-) use the data cache to hold an
640 initial stack and some data.
643 XXX - this list needs to get updated!
647 If this variable is defined, it enables watchdog
648 support. There must be support in the platform specific
649 code for a watchdog. For the 8xx and 8260 CPUs, the
650 SIU Watchdog feature is enabled in the SYPCR
654 CONFIG_VERSION_VARIABLE
655 If this variable is defined, an environment variable
656 named "ver" is created by U-Boot showing the U-Boot
657 version as printed by the "version" command.
658 This variable is readonly.
662 When CONFIG_CMD_DATE is selected, the type of the RTC
663 has to be selected, too. Define exactly one of the
666 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
667 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
668 CONFIG_RTC_MC146818 - use MC146818 RTC
669 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
670 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
671 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
672 CONFIG_RTC_DS164x - use Dallas DS164x RTC
673 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
675 Note that if the RTC uses I2C, then the I2C interface
676 must also be configured. See I2C Support, below.
680 When CONFIG_TIMESTAMP is selected, the timestamp
681 (date and time) of an image is printed by image
682 commands like bootm or iminfo. This option is
683 automatically enabled when you select CONFIG_CMD_DATE .
686 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
687 and/or CONFIG_ISO_PARTITION
689 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
690 CONFIG_CMD_SCSI) you must configure support for at least
691 one partition type as well.
694 CONFIG_IDE_RESET_ROUTINE - this is defined in several
695 board configurations files but used nowhere!
697 CONFIG_IDE_RESET - is this is defined, IDE Reset will
698 be performed by calling the function
699 ide_set_reset(int reset)
700 which has to be defined in a board specific file
705 Set this to enable ATAPI support.
710 Set this to enable support for disks larger than 137GB
711 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
712 Whithout these , LBA48 support uses 32bit variables and will 'only'
713 support disks up to 2.1TB.
716 When enabled, makes the IDE subsystem use 64bit sector addresses.
720 At the moment only there is only support for the
721 SYM53C8XX SCSI controller; define
722 CONFIG_SCSI_SYM53C8XX to enable it.
724 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
725 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
726 CFG_SCSI_MAX_LUN] can be adjusted to define the
727 maximum numbers of LUNs, SCSI ID's and target
729 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
731 - NETWORK Support (PCI):
733 Support for Intel 8254x gigabit chips.
736 Support for Intel 82557/82559/82559ER chips.
737 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
738 write routine for first time initialisation.
741 Support for Digital 2114x chips.
742 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
743 modem chip initialisation (KS8761/QS6611).
746 Support for National dp83815 chips.
749 Support for National dp8382[01] gigabit chips.
751 - NETWORK Support (other):
753 CONFIG_DRIVER_LAN91C96
754 Support for SMSC's LAN91C96 chips.
757 Define this to hold the physical address
758 of the LAN91C96's I/O space
760 CONFIG_LAN91C96_USE_32_BIT
761 Define this to enable 32 bit addressing
763 CONFIG_DRIVER_SMC91111
764 Support for SMSC's LAN91C111 chip
767 Define this to hold the physical address
768 of the device (I/O space)
770 CONFIG_SMC_USE_32_BIT
771 Define this if data bus is 32 bits
773 CONFIG_SMC_USE_IOFUNCS
774 Define this to use i/o functions instead of macros
775 (some hardware wont work with macros)
778 At the moment only the UHCI host controller is
779 supported (PIP405, MIP405, MPC5200); define
780 CONFIG_USB_UHCI to enable it.
781 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
782 and define CONFIG_USB_STORAGE to enable the USB
785 Supported are USB Keyboards and USB Floppy drives
787 MPC5200 USB requires additional defines:
789 for 528 MHz Clock: 0x0001bbbb
791 for differential drivers: 0x00001000
792 for single ended drivers: 0x00005000
794 May be defined to allow interrupt polling
795 instead of using asynchronous interrupts
798 Define the below if you wish to use the USB console.
799 Once firmware is rebuilt from a serial console issue the
800 command "setenv stdin usbtty; setenv stdout usbtty" and
801 attach your usb cable. The Unix command "dmesg" should print
802 it has found a new device. The environment variable usbtty
803 can be set to gserial or cdc_acm to enable your device to
804 appear to a USB host as a Linux gserial device or a
805 Common Device Class Abstract Control Model serial device.
806 If you select usbtty = gserial you should be able to enumerate
808 # modprobe usbserial vendor=0xVendorID product=0xProductID
809 else if using cdc_acm, simply setting the environment
810 variable usbtty to be cdc_acm should suffice. The following
811 might be defined in YourBoardName.h
814 Define this to build a UDC device
817 Define this to have a tty type of device available to
818 talk to the UDC device
820 CFG_CONSOLE_IS_IN_ENV
821 Define this if you want stdin, stdout &/or stderr to
825 CFG_USB_EXTC_CLK 0xBLAH
826 Derive USB clock from external clock "blah"
827 - CFG_USB_EXTC_CLK 0x02
829 CFG_USB_BRG_CLK 0xBLAH
830 Derive USB clock from brgclk
831 - CFG_USB_BRG_CLK 0x04
833 If you have a USB-IF assigned VendorID then you may wish to
834 define your own vendor specific values either in BoardName.h
835 or directly in usbd_vendor_info.h. If you don't define
836 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
837 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
838 should pretend to be a Linux device to it's target host.
840 CONFIG_USBD_MANUFACTURER
841 Define this string as the name of your company for
842 - CONFIG_USBD_MANUFACTURER "my company"
844 CONFIG_USBD_PRODUCT_NAME
845 Define this string as the name of your product
846 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
849 Define this as your assigned Vendor ID from the USB
850 Implementors Forum. This *must* be a genuine Vendor ID
851 to avoid polluting the USB namespace.
852 - CONFIG_USBD_VENDORID 0xFFFF
854 CONFIG_USBD_PRODUCTID
855 Define this as the unique Product ID
857 - CONFIG_USBD_PRODUCTID 0xFFFF
861 The MMC controller on the Intel PXA is supported. To
862 enable this define CONFIG_MMC. The MMC can be
863 accessed from the boot prompt by mapping the device
864 to physical memory similar to flash. Command line is
865 enabled with CONFIG_CMD_MMC. The MMC driver also works with
866 the FAT fs. This is enabled with CONFIG_CMD_FAT.
868 - Journaling Flash filesystem support:
869 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
870 CONFIG_JFFS2_NAND_DEV
871 Define these for a default partition on a NAND device
873 CFG_JFFS2_FIRST_SECTOR,
874 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
875 Define these for a default partition on a NOR device
878 Define this to create an own partition. You have to provide a
879 function struct part_info* jffs2_part_info(int part_num)
881 If you define only one JFFS2 partition you may also want to
882 #define CFG_JFFS_SINGLE_PART 1
883 to disable the command chpart. This is the default when you
884 have not defined a custom partition
889 Define this to enable standard (PC-Style) keyboard
893 Standard PC keyboard driver with US (is default) and
894 GERMAN key layout (switch via environment 'keymap=de') support.
895 Export function i8042_kbd_init, i8042_tstc and i8042_getc
896 for cfb_console. Supports cursor blinking.
901 Define this to enable video support (for output to
906 Enable Chips & Technologies 69000 Video chip
908 CONFIG_VIDEO_SMI_LYNXEM
909 Enable Silicon Motion SMI 712/710/810 Video chip. The
910 video output is selected via environment 'videoout'
911 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
914 For the CT69000 and SMI_LYNXEM drivers, videomode is
915 selected via environment 'videomode'. Two diferent ways
917 - "videomode=num" 'num' is a standard LiLo mode numbers.
918 Following standard modes are supported (* is default):
920 Colors 640x480 800x600 1024x768 1152x864 1280x1024
921 -------------+---------------------------------------------
922 8 bits | 0x301* 0x303 0x305 0x161 0x307
923 15 bits | 0x310 0x313 0x316 0x162 0x319
924 16 bits | 0x311 0x314 0x317 0x163 0x31A
925 24 bits | 0x312 0x315 0x318 ? 0x31B
926 -------------+---------------------------------------------
927 (i.e. setenv videomode 317; saveenv; reset;)
929 - "videomode=bootargs" all the video parameters are parsed
930 from the bootargs. (See drivers/videomodes.c)
933 CONFIG_VIDEO_SED13806
934 Enable Epson SED13806 driver. This driver supports 8bpp
935 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
936 or CONFIG_VIDEO_SED13806_16BPP
941 Define this to enable a custom keyboard support.
942 This simply calls drv_keyboard_init() which must be
943 defined in your board-specific files.
944 The only board using this so far is RBC823.
946 - LCD Support: CONFIG_LCD
948 Define this to enable LCD support (for output to LCD
949 display); also select one of the supported displays
950 by defining one of these:
952 CONFIG_NEC_NL6448AC33:
954 NEC NL6448AC33-18. Active, color, single scan.
956 CONFIG_NEC_NL6448BC20
958 NEC NL6448BC20-08. 6.5", 640x480.
959 Active, color, single scan.
961 CONFIG_NEC_NL6448BC33_54
963 NEC NL6448BC33-54. 10.4", 640x480.
964 Active, color, single scan.
968 Sharp 320x240. Active, color, single scan.
969 It isn't 16x9, and I am not sure what it is.
971 CONFIG_SHARP_LQ64D341
973 Sharp LQ64D341 display, 640x480.
974 Active, color, single scan.
978 HLD1045 display, 640x480.
979 Active, color, single scan.
983 Optrex CBL50840-2 NF-FW 99 22 M5
985 Hitachi LMG6912RPFC-00T
989 320x240. Black & white.
991 Normally display is black on white background; define
992 CFG_WHITE_ON_BLACK to get it inverted.
994 - Splash Screen Support: CONFIG_SPLASH_SCREEN
996 If this option is set, the environment is checked for
997 a variable "splashimage". If found, the usual display
998 of logo, copyright and system information on the LCD
999 is suppressed and the BMP image at the address
1000 specified in "splashimage" is loaded instead. The
1001 console is redirected to the "nulldev", too. This
1002 allows for a "silent" boot where a splash screen is
1003 loaded very quickly after power-on.
1005 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1007 If this option is set, additionally to standard BMP
1008 images, gzipped BMP images can be displayed via the
1009 splashscreen support or the bmp command.
1011 - Compression support:
1014 If this option is set, support for bzip2 compressed
1015 images is included. If not, only uncompressed and gzip
1016 compressed images are supported.
1018 NOTE: the bzip2 algorithm requires a lot of RAM, so
1019 the malloc area (as defined by CFG_MALLOC_LEN) should
1025 The address of PHY on MII bus.
1027 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1029 The clock frequency of the MII bus
1033 If this option is set, support for speed/duplex
1034 detection of Gigabit PHY is included.
1036 CONFIG_PHY_RESET_DELAY
1038 Some PHY like Intel LXT971A need extra delay after
1039 reset before any MII register access is possible.
1040 For such PHY, set this option to the usec delay
1041 required. (minimum 300usec for LXT971A)
1043 CONFIG_PHY_CMD_DELAY (ppc4xx)
1045 Some PHY like Intel LXT971A need extra delay after
1046 command issued before MII status register can be read
1053 Define a default value for ethernet address to use
1054 for the respective ethernet interface, in case this
1055 is not determined automatically.
1060 Define a default value for the IP address to use for
1061 the default ethernet interface, in case this is not
1062 determined through e.g. bootp.
1064 - Server IP address:
1067 Defines a default value for theIP address of a TFTP
1068 server to contact when using the "tftboot" command.
1070 - Multicast TFTP Mode:
1073 Defines whether you want to support multicast TFTP as per
1074 rfc-2090; for example to work with atftp. Lets lots of targets
1075 tftp down the same boot image concurrently. Note: the ethernet
1076 driver in use must provide a function: mcast() to join/leave a
1079 CONFIG_BOOTP_RANDOM_DELAY
1080 - BOOTP Recovery Mode:
1081 CONFIG_BOOTP_RANDOM_DELAY
1083 If you have many targets in a network that try to
1084 boot using BOOTP, you may want to avoid that all
1085 systems send out BOOTP requests at precisely the same
1086 moment (which would happen for instance at recovery
1087 from a power failure, when all systems will try to
1088 boot, thus flooding the BOOTP server. Defining
1089 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1090 inserted before sending out BOOTP requests. The
1091 following delays are inserted then:
1093 1st BOOTP request: delay 0 ... 1 sec
1094 2nd BOOTP request: delay 0 ... 2 sec
1095 3rd BOOTP request: delay 0 ... 4 sec
1097 BOOTP requests: delay 0 ... 8 sec
1099 - DHCP Advanced Options:
1100 You can fine tune the DHCP functionality by defining
1101 CONFIG_BOOTP_* symbols:
1103 CONFIG_BOOTP_SUBNETMASK
1104 CONFIG_BOOTP_GATEWAY
1105 CONFIG_BOOTP_HOSTNAME
1106 CONFIG_BOOTP_NISDOMAIN
1107 CONFIG_BOOTP_BOOTPATH
1108 CONFIG_BOOTP_BOOTFILESIZE
1111 CONFIG_BOOTP_SEND_HOSTNAME
1112 CONFIG_BOOTP_NTPSERVER
1113 CONFIG_BOOTP_TIMEOFFSET
1114 CONFIG_BOOTP_VENDOREX
1116 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1117 environment variable, not the BOOTP server.
1119 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1120 serverip from a DHCP server, it is possible that more
1121 than one DNS serverip is offered to the client.
1122 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1123 serverip will be stored in the additional environment
1124 variable "dnsip2". The first DNS serverip is always
1125 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1128 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1129 to do a dynamic update of a DNS server. To do this, they
1130 need the hostname of the DHCP requester.
1131 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1132 of the "hostname" environment variable is passed as
1133 option 12 to the DHCP server.
1136 CONFIG_CDP_DEVICE_ID
1138 The device id used in CDP trigger frames.
1140 CONFIG_CDP_DEVICE_ID_PREFIX
1142 A two character string which is prefixed to the MAC address
1147 A printf format string which contains the ascii name of
1148 the port. Normally is set to "eth%d" which sets
1149 eth0 for the first ethernet, eth1 for the second etc.
1151 CONFIG_CDP_CAPABILITIES
1153 A 32bit integer which indicates the device capabilities;
1154 0x00000010 for a normal host which does not forwards.
1158 An ascii string containing the version of the software.
1162 An ascii string containing the name of the platform.
1166 A 32bit integer sent on the trigger.
1168 CONFIG_CDP_POWER_CONSUMPTION
1170 A 16bit integer containing the power consumption of the
1171 device in .1 of milliwatts.
1173 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1175 A byte containing the id of the VLAN.
1177 - Status LED: CONFIG_STATUS_LED
1179 Several configurations allow to display the current
1180 status using a LED. For instance, the LED will blink
1181 fast while running U-Boot code, stop blinking as
1182 soon as a reply to a BOOTP request was received, and
1183 start blinking slow once the Linux kernel is running
1184 (supported by a status LED driver in the Linux
1185 kernel). Defining CONFIG_STATUS_LED enables this
1188 - CAN Support: CONFIG_CAN_DRIVER
1190 Defining CONFIG_CAN_DRIVER enables CAN driver support
1191 on those systems that support this (optional)
1192 feature, like the TQM8xxL modules.
1194 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1196 These enable I2C serial bus commands. Defining either of
1197 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1198 include the appropriate I2C driver for the selected cpu.
1200 This will allow you to use i2c commands at the u-boot
1201 command line (as long as you set CONFIG_CMD_I2C in
1202 CONFIG_COMMANDS) and communicate with i2c based realtime
1203 clock chips. See common/cmd_i2c.c for a description of the
1204 command line interface.
1206 CONFIG_I2C_CMD_TREE is a recommended option that places
1207 all I2C commands under a single 'i2c' root command. The
1208 older 'imm', 'imd', 'iprobe' etc. commands are considered
1209 deprecated and may disappear in the future.
1211 CONFIG_HARD_I2C selects a hardware I2C controller.
1213 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1214 bit-banging) driver instead of CPM or similar hardware
1217 There are several other quantities that must also be
1218 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1220 In both cases you will need to define CFG_I2C_SPEED
1221 to be the frequency (in Hz) at which you wish your i2c bus
1222 to run and CFG_I2C_SLAVE to be the address of this node (ie
1223 the cpu's i2c node address).
1225 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1226 sets the cpu up as a master node and so its address should
1227 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1228 p.16-473). So, set CFG_I2C_SLAVE to 0.
1230 That's all that's required for CONFIG_HARD_I2C.
1232 If you use the software i2c interface (CONFIG_SOFT_I2C)
1233 then the following macros need to be defined (examples are
1234 from include/configs/lwmon.h):
1238 (Optional). Any commands necessary to enable the I2C
1239 controller or configure ports.
1241 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1245 (Only for MPC8260 CPU). The I/O port to use (the code
1246 assumes both bits are on the same port). Valid values
1247 are 0..3 for ports A..D.
1251 The code necessary to make the I2C data line active
1252 (driven). If the data line is open collector, this
1255 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1259 The code necessary to make the I2C data line tri-stated
1260 (inactive). If the data line is open collector, this
1263 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1267 Code that returns TRUE if the I2C data line is high,
1270 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1274 If <bit> is TRUE, sets the I2C data line high. If it
1275 is FALSE, it clears it (low).
1277 eg: #define I2C_SDA(bit) \
1278 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1279 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1283 If <bit> is TRUE, sets the I2C clock line high. If it
1284 is FALSE, it clears it (low).
1286 eg: #define I2C_SCL(bit) \
1287 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1288 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1292 This delay is invoked four times per clock cycle so this
1293 controls the rate of data transfer. The data rate thus
1294 is 1 / (I2C_DELAY * 4). Often defined to be something
1297 #define I2C_DELAY udelay(2)
1301 When a board is reset during an i2c bus transfer
1302 chips might think that the current transfer is still
1303 in progress. On some boards it is possible to access
1304 the i2c SCLK line directly, either by using the
1305 processor pin as a GPIO or by having a second pin
1306 connected to the bus. If this option is defined a
1307 custom i2c_init_board() routine in boards/xxx/board.c
1308 is run early in the boot sequence.
1310 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1312 This option enables configuration of bi_iic_fast[] flags
1313 in u-boot bd_info structure based on u-boot environment
1314 variable "i2cfast". (see also i2cfast)
1316 CONFIG_I2C_MULTI_BUS
1318 This option allows the use of multiple I2C buses, each of which
1319 must have a controller. At any point in time, only one bus is
1320 active. To switch to a different bus, use the 'i2c dev' command.
1321 Note that bus numbering is zero-based.
1325 This option specifies a list of I2C devices that will be skipped
1326 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1327 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1328 pairs. Otherwise, specify a 1D array of device addresses
1331 #undef CONFIG_I2C_MULTI_BUS
1332 #define CFG_I2C_NOPROBES {0x50,0x68}
1334 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1336 #define CONFIG_I2C_MULTI_BUS
1337 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1339 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1343 If defined, then this indicates the I2C bus number for DDR SPD.
1344 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1348 If defined, then this indicates the I2C bus number for the RTC.
1349 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1353 If defined, then this indicates the I2C bus number for the DTT.
1354 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1358 Define this option if you want to use Freescale's I2C driver in
1362 - SPI Support: CONFIG_SPI
1364 Enables SPI driver (so far only tested with
1365 SPI EEPROM, also an instance works with Crystal A/D and
1366 D/As on the SACSng board)
1370 Enables extended (16-bit) SPI EEPROM addressing.
1371 (symmetrical to CONFIG_I2C_X)
1375 Enables a software (bit-bang) SPI driver rather than
1376 using hardware support. This is a general purpose
1377 driver that only requires three general I/O port pins
1378 (two outputs, one input) to function. If this is
1379 defined, the board configuration must define several
1380 SPI configuration items (port pins to use, etc). For
1381 an example, see include/configs/sacsng.h.
1383 - FPGA Support: CONFIG_FPGA_COUNT
1385 Specify the number of FPGA devices to support.
1389 Used to specify the types of FPGA devices. For example,
1390 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1392 CFG_FPGA_PROG_FEEDBACK
1394 Enable printing of hash marks during FPGA configuration.
1398 Enable checks on FPGA configuration interface busy
1399 status by the configuration function. This option
1400 will require a board or device specific function to
1405 If defined, a function that provides delays in the FPGA
1406 configuration driver.
1408 CFG_FPGA_CHECK_CTRLC
1409 Allow Control-C to interrupt FPGA configuration
1411 CFG_FPGA_CHECK_ERROR
1413 Check for configuration errors during FPGA bitfile
1414 loading. For example, abort during Virtex II
1415 configuration if the INIT_B line goes low (which
1416 indicated a CRC error).
1420 Maximum time to wait for the INIT_B line to deassert
1421 after PROB_B has been deasserted during a Virtex II
1422 FPGA configuration sequence. The default time is 500
1427 Maximum time to wait for BUSY to deassert during
1428 Virtex II FPGA configuration. The default is 5 mS.
1430 CFG_FPGA_WAIT_CONFIG
1432 Time to wait after FPGA configuration. The default is
1435 - Configuration Management:
1438 If defined, this string will be added to the U-Boot
1439 version information (U_BOOT_VERSION)
1441 - Vendor Parameter Protection:
1443 U-Boot considers the values of the environment
1444 variables "serial#" (Board Serial Number) and
1445 "ethaddr" (Ethernet Address) to be parameters that
1446 are set once by the board vendor / manufacturer, and
1447 protects these variables from casual modification by
1448 the user. Once set, these variables are read-only,
1449 and write or delete attempts are rejected. You can
1450 change this behviour:
1452 If CONFIG_ENV_OVERWRITE is #defined in your config
1453 file, the write protection for vendor parameters is
1454 completely disabled. Anybody can change or delete
1457 Alternatively, if you #define _both_ CONFIG_ETHADDR
1458 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1459 ethernet address is installed in the environment,
1460 which can be changed exactly ONCE by the user. [The
1461 serial# is unaffected by this, i. e. it remains
1467 Define this variable to enable the reservation of
1468 "protected RAM", i. e. RAM which is not overwritten
1469 by U-Boot. Define CONFIG_PRAM to hold the number of
1470 kB you want to reserve for pRAM. You can overwrite
1471 this default value by defining an environment
1472 variable "pram" to the number of kB you want to
1473 reserve. Note that the board info structure will
1474 still show the full amount of RAM. If pRAM is
1475 reserved, a new environment variable "mem" will
1476 automatically be defined to hold the amount of
1477 remaining RAM in a form that can be passed as boot
1478 argument to Linux, for instance like that:
1480 setenv bootargs ... mem=\${mem}
1483 This way you can tell Linux not to use this memory,
1484 either, which results in a memory region that will
1485 not be affected by reboots.
1487 *WARNING* If your board configuration uses automatic
1488 detection of the RAM size, you must make sure that
1489 this memory test is non-destructive. So far, the
1490 following board configurations are known to be
1493 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1494 HERMES, IP860, RPXlite, LWMON, LANTEC,
1495 PCU_E, FLAGADM, TQM8260
1500 Define this variable to stop the system in case of a
1501 fatal error, so that you have to reset it manually.
1502 This is probably NOT a good idea for an embedded
1503 system where you want to system to reboot
1504 automatically as fast as possible, but it may be
1505 useful during development since you can try to debug
1506 the conditions that lead to the situation.
1508 CONFIG_NET_RETRY_COUNT
1510 This variable defines the number of retries for
1511 network operations like ARP, RARP, TFTP, or BOOTP
1512 before giving up the operation. If not defined, a
1513 default value of 5 is used.
1515 - Command Interpreter:
1516 CONFIG_AUTO_COMPLETE
1518 Enable auto completion of commands using TAB.
1520 Note that this feature has NOT been implemented yet
1521 for the "hush" shell.
1526 Define this variable to enable the "hush" shell (from
1527 Busybox) as command line interpreter, thus enabling
1528 powerful command line syntax like
1529 if...then...else...fi conditionals or `&&' and '||'
1530 constructs ("shell scripts").
1532 If undefined, you get the old, much simpler behaviour
1533 with a somewhat smaller memory footprint.
1538 This defines the secondary prompt string, which is
1539 printed when the command interpreter needs more input
1540 to complete a command. Usually "> ".
1544 In the current implementation, the local variables
1545 space and global environment variables space are
1546 separated. Local variables are those you define by
1547 simply typing `name=value'. To access a local
1548 variable later on, you have write `$name' or
1549 `${name}'; to execute the contents of a variable
1550 directly type `$name' at the command prompt.
1552 Global environment variables are those you use
1553 setenv/printenv to work with. To run a command stored
1554 in such a variable, you need to use the run command,
1555 and you must not use the '$' sign to access them.
1557 To store commands and special characters in a
1558 variable, please use double quotation marks
1559 surrounding the whole text of the variable, instead
1560 of the backslashes before semicolons and special
1563 - Commandline Editing and History:
1564 CONFIG_CMDLINE_EDITING
1566 Enable editiong and History functions for interactive
1567 commandline input operations
1569 - Default Environment:
1570 CONFIG_EXTRA_ENV_SETTINGS
1572 Define this to contain any number of null terminated
1573 strings (variable = value pairs) that will be part of
1574 the default environment compiled into the boot image.
1576 For example, place something like this in your
1577 board's config file:
1579 #define CONFIG_EXTRA_ENV_SETTINGS \
1583 Warning: This method is based on knowledge about the
1584 internal format how the environment is stored by the
1585 U-Boot code. This is NOT an official, exported
1586 interface! Although it is unlikely that this format
1587 will change soon, there is no guarantee either.
1588 You better know what you are doing here.
1590 Note: overly (ab)use of the default environment is
1591 discouraged. Make sure to check other ways to preset
1592 the environment like the autoscript function or the
1595 - DataFlash Support:
1596 CONFIG_HAS_DATAFLASH
1598 Defining this option enables DataFlash features and
1599 allows to read/write in Dataflash via the standard
1602 - SystemACE Support:
1605 Adding this option adds support for Xilinx SystemACE
1606 chips attached via some sort of local bus. The address
1607 of the chip must alsh be defined in the
1608 CFG_SYSTEMACE_BASE macro. For example:
1610 #define CONFIG_SYSTEMACE
1611 #define CFG_SYSTEMACE_BASE 0xf0000000
1613 When SystemACE support is added, the "ace" device type
1614 becomes available to the fat commands, i.e. fatls.
1616 - TFTP Fixed UDP Port:
1619 If this is defined, the environment variable tftpsrcp
1620 is used to supply the TFTP UDP source port value.
1621 If tftpsrcp isn't defined, the normal pseudo-random port
1622 number generator is used.
1624 Also, the environment variable tftpdstp is used to supply
1625 the TFTP UDP destination port value. If tftpdstp isn't
1626 defined, the normal port 69 is used.
1628 The purpose for tftpsrcp is to allow a TFTP server to
1629 blindly start the TFTP transfer using the pre-configured
1630 target IP address and UDP port. This has the effect of
1631 "punching through" the (Windows XP) firewall, allowing
1632 the remainder of the TFTP transfer to proceed normally.
1633 A better solution is to properly configure the firewall,
1634 but sometimes that is not allowed.
1636 - Show boot progress:
1637 CONFIG_SHOW_BOOT_PROGRESS
1639 Defining this option allows to add some board-
1640 specific code (calling a user-provided function
1641 "show_boot_progress(int)") that enables you to show
1642 the system's boot progress on some display (for
1643 example, some LED's) on your board. At the moment,
1644 the following checkpoints are implemented:
1647 1 common/cmd_bootm.c before attempting to boot an image
1648 -1 common/cmd_bootm.c Image header has bad magic number
1649 2 common/cmd_bootm.c Image header has correct magic number
1650 -2 common/cmd_bootm.c Image header has bad checksum
1651 3 common/cmd_bootm.c Image header has correct checksum
1652 -3 common/cmd_bootm.c Image data has bad checksum
1653 4 common/cmd_bootm.c Image data has correct checksum
1654 -4 common/cmd_bootm.c Image is for unsupported architecture
1655 5 common/cmd_bootm.c Architecture check OK
1656 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1657 6 common/cmd_bootm.c Image Type check OK
1658 -6 common/cmd_bootm.c gunzip uncompression error
1659 -7 common/cmd_bootm.c Unimplemented compression type
1660 7 common/cmd_bootm.c Uncompression OK
1661 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1662 8 common/cmd_bootm.c Image Type check OK
1663 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1664 9 common/cmd_bootm.c Start initial ramdisk verification
1665 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1666 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1667 10 common/cmd_bootm.c Ramdisk header is OK
1668 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1669 11 common/cmd_bootm.c Ramdisk data has correct checksum
1670 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1671 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1672 13 common/cmd_bootm.c Start multifile image verification
1673 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1674 15 common/cmd_bootm.c All preparation done, transferring control to OS
1676 -30 lib_ppc/board.c Fatal error, hang the system
1677 -31 post/post.c POST test failed, detected by post_output_backlog()
1678 -32 post/post.c POST test failed, detected by post_run_single()
1680 34 common/cmd_doc.c before loading a Image from a DOC device
1681 -35 common/cmd_doc.c Bad usage of "doc" command
1682 35 common/cmd_doc.c correct usage of "doc" command
1683 -36 common/cmd_doc.c No boot device
1684 36 common/cmd_doc.c correct boot device
1685 -37 common/cmd_doc.c Unknown Chip ID on boot device
1686 37 common/cmd_doc.c correct chip ID found, device available
1687 -38 common/cmd_doc.c Read Error on boot device
1688 38 common/cmd_doc.c reading Image header from DOC device OK
1689 -39 common/cmd_doc.c Image header has bad magic number
1690 39 common/cmd_doc.c Image header has correct magic number
1691 -40 common/cmd_doc.c Error reading Image from DOC device
1692 40 common/cmd_doc.c Image header has correct magic number
1693 41 common/cmd_ide.c before loading a Image from a IDE device
1694 -42 common/cmd_ide.c Bad usage of "ide" command
1695 42 common/cmd_ide.c correct usage of "ide" command
1696 -43 common/cmd_ide.c No boot device
1697 43 common/cmd_ide.c boot device found
1698 -44 common/cmd_ide.c Device not available
1699 44 common/cmd_ide.c Device available
1700 -45 common/cmd_ide.c wrong partition selected
1701 45 common/cmd_ide.c partition selected
1702 -46 common/cmd_ide.c Unknown partition table
1703 46 common/cmd_ide.c valid partition table found
1704 -47 common/cmd_ide.c Invalid partition type
1705 47 common/cmd_ide.c correct partition type
1706 -48 common/cmd_ide.c Error reading Image Header on boot device
1707 48 common/cmd_ide.c reading Image Header from IDE device OK
1708 -49 common/cmd_ide.c Image header has bad magic number
1709 49 common/cmd_ide.c Image header has correct magic number
1710 -50 common/cmd_ide.c Image header has bad checksum
1711 50 common/cmd_ide.c Image header has correct checksum
1712 -51 common/cmd_ide.c Error reading Image from IDE device
1713 51 common/cmd_ide.c reading Image from IDE device OK
1714 52 common/cmd_nand.c before loading a Image from a NAND device
1715 -53 common/cmd_nand.c Bad usage of "nand" command
1716 53 common/cmd_nand.c correct usage of "nand" command
1717 -54 common/cmd_nand.c No boot device
1718 54 common/cmd_nand.c boot device found
1719 -55 common/cmd_nand.c Unknown Chip ID on boot device
1720 55 common/cmd_nand.c correct chip ID found, device available
1721 -56 common/cmd_nand.c Error reading Image Header on boot device
1722 56 common/cmd_nand.c reading Image Header from NAND device OK
1723 -57 common/cmd_nand.c Image header has bad magic number
1724 57 common/cmd_nand.c Image header has correct magic number
1725 -58 common/cmd_nand.c Error reading Image from NAND device
1726 58 common/cmd_nand.c reading Image from NAND device OK
1728 -60 common/env_common.c Environment has a bad CRC, using default
1730 64 net/eth.c starting with Ethernetconfiguration.
1731 -64 net/eth.c no Ethernet found.
1732 65 net/eth.c Ethernet found.
1734 -80 common/cmd_net.c usage wrong
1735 80 common/cmd_net.c before calling NetLoop()
1736 -81 common/cmd_net.c some error in NetLoop() occured
1737 81 common/cmd_net.c NetLoop() back without error
1738 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1739 82 common/cmd_net.c trying automatic boot
1740 83 common/cmd_net.c running autoscript
1741 -83 common/cmd_net.c some error in automatic boot or autoscript
1742 84 common/cmd_net.c end without errors
1747 [so far only for SMDK2400 and TRAB boards]
1749 - Modem support endable:
1750 CONFIG_MODEM_SUPPORT
1752 - RTS/CTS Flow control enable:
1755 - Modem debug support:
1756 CONFIG_MODEM_SUPPORT_DEBUG
1758 Enables debugging stuff (char screen[1024], dbg())
1759 for modem support. Useful only with BDI2000.
1761 - Interrupt support (PPC):
1763 There are common interrupt_init() and timer_interrupt()
1764 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1765 for cpu specific initialization. interrupt_init_cpu()
1766 should set decrementer_count to appropriate value. If
1767 cpu resets decrementer automatically after interrupt
1768 (ppc4xx) it should set decrementer_count to zero.
1769 timer_interrupt() calls timer_interrupt_cpu() for cpu
1770 specific handling. If board has watchdog / status_led
1771 / other_activity_monitor it works automatically from
1772 general timer_interrupt().
1776 In the target system modem support is enabled when a
1777 specific key (key combination) is pressed during
1778 power-on. Otherwise U-Boot will boot normally
1779 (autoboot). The key_pressed() fuction is called from
1780 board_init(). Currently key_pressed() is a dummy
1781 function, returning 1 and thus enabling modem
1784 If there are no modem init strings in the
1785 environment, U-Boot proceed to autoboot; the
1786 previous output (banner, info printfs) will be
1789 See also: doc/README.Modem
1792 Configuration Settings:
1793 -----------------------
1795 - CFG_LONGHELP: Defined when you want long help messages included;
1796 undefine this when you're short of memory.
1798 - CFG_PROMPT: This is what U-Boot prints on the console to
1799 prompt for user input.
1801 - CFG_CBSIZE: Buffer size for input from the Console
1803 - CFG_PBSIZE: Buffer size for Console output
1805 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1807 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1808 the application (usually a Linux kernel) when it is
1811 - CFG_BAUDRATE_TABLE:
1812 List of legal baudrate settings for this board.
1814 - CFG_CONSOLE_INFO_QUIET
1815 Suppress display of console information at boot.
1817 - CFG_CONSOLE_IS_IN_ENV
1818 If the board specific function
1819 extern int overwrite_console (void);
1820 returns 1, the stdin, stderr and stdout are switched to the
1821 serial port, else the settings in the environment are used.
1823 - CFG_CONSOLE_OVERWRITE_ROUTINE
1824 Enable the call to overwrite_console().
1826 - CFG_CONSOLE_ENV_OVERWRITE
1827 Enable overwrite of previous console environment settings.
1829 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1830 Begin and End addresses of the area used by the
1834 Enable an alternate, more extensive memory test.
1836 - CFG_MEMTEST_SCRATCH:
1837 Scratch address used by the alternate memory test
1838 You only need to set this if address zero isn't writeable
1840 - CFG_TFTP_LOADADDR:
1841 Default load address for network file downloads
1843 - CFG_LOADS_BAUD_CHANGE:
1844 Enable temporary baudrate change while serial download
1847 Physical start address of SDRAM. _Must_ be 0 here.
1850 Physical start address of Motherboard I/O (if using a
1854 Physical start address of Flash memory.
1857 Physical start address of boot monitor code (set by
1858 make config files to be same as the text base address
1859 (TEXT_BASE) used when linking) - same as
1860 CFG_FLASH_BASE when booting from flash.
1863 Size of memory reserved for monitor code, used to
1864 determine _at_compile_time_ (!) if the environment is
1865 embedded within the U-Boot image, or in a separate
1869 Size of DRAM reserved for malloc() use.
1872 Normally compressed uImages are limited to an
1873 uncompressed size of 8 MBytes. If this is not enough,
1874 you can define CFG_BOOTM_LEN in your board config file
1875 to adjust this setting to your needs.
1878 Maximum size of memory mapped by the startup code of
1879 the Linux kernel; all data that must be processed by
1880 the Linux kernel (bd_info, boot arguments, eventually
1881 initrd image) must be put below this limit.
1883 - CFG_MAX_FLASH_BANKS:
1884 Max number of Flash memory banks
1886 - CFG_MAX_FLASH_SECT:
1887 Max number of sectors on a Flash chip
1889 - CFG_FLASH_ERASE_TOUT:
1890 Timeout for Flash erase operations (in ms)
1892 - CFG_FLASH_WRITE_TOUT:
1893 Timeout for Flash write operations (in ms)
1895 - CFG_FLASH_LOCK_TOUT
1896 Timeout for Flash set sector lock bit operation (in ms)
1898 - CFG_FLASH_UNLOCK_TOUT
1899 Timeout for Flash clear lock bits operation (in ms)
1901 - CFG_FLASH_PROTECTION
1902 If defined, hardware flash sectors protection is used
1903 instead of U-Boot software protection.
1905 - CFG_DIRECT_FLASH_TFTP:
1907 Enable TFTP transfers directly to flash memory;
1908 without this option such a download has to be
1909 performed in two steps: (1) download to RAM, and (2)
1910 copy from RAM to flash.
1912 The two-step approach is usually more reliable, since
1913 you can check if the download worked before you erase
1914 the flash, but in some situations (when sytem RAM is
1915 too limited to allow for a tempory copy of the
1916 downloaded image) this option may be very useful.
1919 Define if the flash driver uses extra elements in the
1920 common flash structure for storing flash geometry.
1922 - CFG_FLASH_CFI_DRIVER
1923 This option also enables the building of the cfi_flash driver
1924 in the drivers directory
1926 - CFG_FLASH_QUIET_TEST
1927 If this option is defined, the common CFI flash doesn't
1928 print it's warning upon not recognized FLASH banks. This
1929 is useful, if some of the configured banks are only
1930 optionally available.
1932 - CFG_RX_ETH_BUFFER:
1933 Defines the number of ethernet receive buffers. On some
1934 ethernet controllers it is recommended to set this value
1935 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1936 buffers can be full shortly after enabling the interface
1937 on high ethernet traffic.
1938 Defaults to 4 if not defined.
1940 The following definitions that deal with the placement and management
1941 of environment data (variable area); in general, we support the
1942 following configurations:
1944 - CFG_ENV_IS_IN_FLASH:
1946 Define this if the environment is in flash memory.
1948 a) The environment occupies one whole flash sector, which is
1949 "embedded" in the text segment with the U-Boot code. This
1950 happens usually with "bottom boot sector" or "top boot
1951 sector" type flash chips, which have several smaller
1952 sectors at the start or the end. For instance, such a
1953 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1954 such a case you would place the environment in one of the
1955 4 kB sectors - with U-Boot code before and after it. With
1956 "top boot sector" type flash chips, you would put the
1957 environment in one of the last sectors, leaving a gap
1958 between U-Boot and the environment.
1962 Offset of environment data (variable area) to the
1963 beginning of flash memory; for instance, with bottom boot
1964 type flash chips the second sector can be used: the offset
1965 for this sector is given here.
1967 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1971 This is just another way to specify the start address of
1972 the flash sector containing the environment (instead of
1975 - CFG_ENV_SECT_SIZE:
1977 Size of the sector containing the environment.
1980 b) Sometimes flash chips have few, equal sized, BIG sectors.
1981 In such a case you don't want to spend a whole sector for
1986 If you use this in combination with CFG_ENV_IS_IN_FLASH
1987 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1988 of this flash sector for the environment. This saves
1989 memory for the RAM copy of the environment.
1991 It may also save flash memory if you decide to use this
1992 when your environment is "embedded" within U-Boot code,
1993 since then the remainder of the flash sector could be used
1994 for U-Boot code. It should be pointed out that this is
1995 STRONGLY DISCOURAGED from a robustness point of view:
1996 updating the environment in flash makes it always
1997 necessary to erase the WHOLE sector. If something goes
1998 wrong before the contents has been restored from a copy in
1999 RAM, your target system will be dead.
2001 - CFG_ENV_ADDR_REDUND
2004 These settings describe a second storage area used to hold
2005 a redundand copy of the environment data, so that there is
2006 a valid backup copy in case there is a power failure during
2007 a "saveenv" operation.
2009 BE CAREFUL! Any changes to the flash layout, and some changes to the
2010 source code will make it necessary to adapt <board>/u-boot.lds*
2014 - CFG_ENV_IS_IN_NVRAM:
2016 Define this if you have some non-volatile memory device
2017 (NVRAM, battery buffered SRAM) which you want to use for the
2023 These two #defines are used to determin the memory area you
2024 want to use for environment. It is assumed that this memory
2025 can just be read and written to, without any special
2028 BE CAREFUL! The first access to the environment happens quite early
2029 in U-Boot initalization (when we try to get the setting of for the
2030 console baudrate). You *MUST* have mappend your NVRAM area then, or
2033 Please note that even with NVRAM we still use a copy of the
2034 environment in RAM: we could work on NVRAM directly, but we want to
2035 keep settings there always unmodified except somebody uses "saveenv"
2036 to save the current settings.
2039 - CFG_ENV_IS_IN_EEPROM:
2041 Use this if you have an EEPROM or similar serial access
2042 device and a driver for it.
2047 These two #defines specify the offset and size of the
2048 environment area within the total memory of your EEPROM.
2050 - CFG_I2C_EEPROM_ADDR:
2051 If defined, specified the chip address of the EEPROM device.
2052 The default address is zero.
2054 - CFG_EEPROM_PAGE_WRITE_BITS:
2055 If defined, the number of bits used to address bytes in a
2056 single page in the EEPROM device. A 64 byte page, for example
2057 would require six bits.
2059 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2060 If defined, the number of milliseconds to delay between
2061 page writes. The default is zero milliseconds.
2063 - CFG_I2C_EEPROM_ADDR_LEN:
2064 The length in bytes of the EEPROM memory array address. Note
2065 that this is NOT the chip address length!
2067 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2068 EEPROM chips that implement "address overflow" are ones
2069 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2070 address and the extra bits end up in the "chip address" bit
2071 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2074 Note that we consider the length of the address field to
2075 still be one byte because the extra address bits are hidden
2076 in the chip address.
2079 The size in bytes of the EEPROM device.
2082 - CFG_ENV_IS_IN_DATAFLASH:
2084 Define this if you have a DataFlash memory device which you
2085 want to use for the environment.
2091 These three #defines specify the offset and size of the
2092 environment area within the total memory of your DataFlash placed
2093 at the specified address.
2095 - CFG_ENV_IS_IN_NAND:
2097 Define this if you have a NAND device which you want to use
2098 for the environment.
2103 These two #defines specify the offset and size of the environment
2104 area within the first NAND device.
2106 - CFG_ENV_OFFSET_REDUND
2108 This setting describes a second storage area of CFG_ENV_SIZE
2109 size used to hold a redundant copy of the environment data,
2110 so that there is a valid backup copy in case there is a
2111 power failure during a "saveenv" operation.
2113 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2114 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2115 the NAND devices block size.
2117 - CFG_SPI_INIT_OFFSET
2119 Defines offset to the initial SPI buffer area in DPRAM. The
2120 area is used at an early stage (ROM part) if the environment
2121 is configured to reside in the SPI EEPROM: We need a 520 byte
2122 scratch DPRAM area. It is used between the two initialization
2123 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2124 to be a good choice since it makes it far enough from the
2125 start of the data area as well as from the stack pointer.
2127 Please note that the environment is read-only as long as the monitor
2128 has been relocated to RAM and a RAM copy of the environment has been
2129 created; also, when using EEPROM you will have to use getenv_r()
2130 until then to read environment variables.
2132 The environment is protected by a CRC32 checksum. Before the monitor
2133 is relocated into RAM, as a result of a bad CRC you will be working
2134 with the compiled-in default environment - *silently*!!! [This is
2135 necessary, because the first environment variable we need is the
2136 "baudrate" setting for the console - if we have a bad CRC, we don't
2137 have any device yet where we could complain.]
2139 Note: once the monitor has been relocated, then it will complain if
2140 the default environment is used; a new CRC is computed as soon as you
2141 use the "saveenv" command to store a valid environment.
2143 - CFG_FAULT_ECHO_LINK_DOWN:
2144 Echo the inverted Ethernet link state to the fault LED.
2146 Note: If this option is active, then CFG_FAULT_MII_ADDR
2147 also needs to be defined.
2149 - CFG_FAULT_MII_ADDR:
2150 MII address of the PHY to check for the Ethernet link state.
2152 - CFG_64BIT_VSPRINTF:
2153 Makes vsprintf (and all *printf functions) support printing
2154 of 64bit values by using the L quantifier
2156 - CFG_64BIT_STRTOUL:
2157 Adds simple_strtoull that returns a 64bit value
2159 Low Level (hardware related) configuration options:
2160 ---------------------------------------------------
2162 - CFG_CACHELINE_SIZE:
2163 Cache Line Size of the CPU.
2166 Default address of the IMMR after system reset.
2168 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2169 and RPXsuper) to be able to adjust the position of
2170 the IMMR register after a reset.
2172 - Floppy Disk Support:
2173 CFG_FDC_DRIVE_NUMBER
2175 the default drive number (default value 0)
2179 defines the spacing between fdc chipset registers
2184 defines the offset of register from address. It
2185 depends on which part of the data bus is connected to
2186 the fdc chipset. (default value 0)
2188 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2189 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2192 if CFG_FDC_HW_INIT is defined, then the function
2193 fdc_hw_init() is called at the beginning of the FDC
2194 setup. fdc_hw_init() must be provided by the board
2195 source code. It is used to make hardware dependant
2198 - CFG_IMMR: Physical address of the Internal Memory.
2199 DO NOT CHANGE unless you know exactly what you're
2200 doing! (11-4) [MPC8xx/82xx systems only]
2202 - CFG_INIT_RAM_ADDR:
2204 Start address of memory area that can be used for
2205 initial data and stack; please note that this must be
2206 writable memory that is working WITHOUT special
2207 initialization, i. e. you CANNOT use normal RAM which
2208 will become available only after programming the
2209 memory controller and running certain initialization
2212 U-Boot uses the following memory types:
2213 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2214 - MPC824X: data cache
2215 - PPC4xx: data cache
2217 - CFG_GBL_DATA_OFFSET:
2219 Offset of the initial data structure in the memory
2220 area defined by CFG_INIT_RAM_ADDR. Usually
2221 CFG_GBL_DATA_OFFSET is chosen such that the initial
2222 data is located at the end of the available space
2223 (sometimes written as (CFG_INIT_RAM_END -
2224 CFG_INIT_DATA_SIZE), and the initial stack is just
2225 below that area (growing from (CFG_INIT_RAM_ADDR +
2226 CFG_GBL_DATA_OFFSET) downward.
2229 On the MPC824X (or other systems that use the data
2230 cache for initial memory) the address chosen for
2231 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2232 point to an otherwise UNUSED address space between
2233 the top of RAM and the start of the PCI space.
2235 - CFG_SIUMCR: SIU Module Configuration (11-6)
2237 - CFG_SYPCR: System Protection Control (11-9)
2239 - CFG_TBSCR: Time Base Status and Control (11-26)
2241 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2243 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2245 - CFG_SCCR: System Clock and reset Control Register (15-27)
2247 - CFG_OR_TIMING_SDRAM:
2251 periodic timer for refresh
2253 - CFG_DER: Debug Event Register (37-47)
2255 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2256 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2257 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2259 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2261 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2262 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2263 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2264 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2266 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2267 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2268 Machine Mode Register and Memory Periodic Timer
2269 Prescaler definitions (SDRAM timing)
2271 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2272 enable I2C microcode relocation patch (MPC8xx);
2273 define relocation offset in DPRAM [DSP2]
2275 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2276 enable SPI microcode relocation patch (MPC8xx);
2277 define relocation offset in DPRAM [SCC4]
2280 Use OSCM clock mode on MBX8xx board. Be careful,
2281 wrong setting might damage your board. Read
2282 doc/README.MBX before setting this variable!
2284 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2285 Offset of the bootmode word in DPRAM used by post
2286 (Power On Self Tests). This definition overrides
2287 #define'd default value in commproc.h resp.
2290 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2291 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2292 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2293 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2294 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2295 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2296 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2297 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2298 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2301 Get DDR timing information from an I2C EEPROM. Common with pluggable
2302 memory modules such as SODIMMs
2304 I2C address of the SPD EEPROM
2307 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2308 Note that the value must resolve to something your driver can deal with.
2310 - CFG_83XX_DDR_USES_CS0
2311 Only for 83xx systems. If specified, then DDR should be configured
2312 using CS0 and CS1 instead of CS2 and CS3.
2314 - CFG_83XX_DDR_USES_CS0
2315 Only for 83xx systems. If specified, then DDR should be configured
2316 using CS0 and CS1 instead of CS2 and CS3.
2318 - CONFIG_ETHER_ON_FEC[12]
2319 Define to enable FEC[12] on a 8xx series processor.
2321 - CONFIG_FEC[12]_PHY
2322 Define to the hardcoded PHY address which corresponds
2323 to the given FEC; i. e.
2324 #define CONFIG_FEC1_PHY 4
2325 means that the PHY with address 4 is connected to FEC1
2327 When set to -1, means to probe for first available.
2329 - CONFIG_FEC[12]_PHY_NORXERR
2330 The PHY does not have a RXERR line (RMII only).
2331 (so program the FEC to ignore it).
2334 Enable RMII mode for all FECs.
2335 Note that this is a global option, we can't
2336 have one FEC in standard MII mode and another in RMII mode.
2338 - CONFIG_CRC32_VERIFY
2339 Add a verify option to the crc32 command.
2342 => crc32 -v <address> <count> <crc32>
2344 Where address/count indicate a memory area
2345 and crc32 is the correct crc32 which the
2349 Add the "loopw" memory command. This only takes effect if
2350 the memory commands are activated globally (CONFIG_CMD_MEM).
2353 Add the "mdc" and "mwc" memory commands. These are cyclic
2358 This command will print 4 bytes (10,11,12,13) each 500 ms.
2360 => mwc.l 100 12345678 10
2361 This command will write 12345678 to address 100 all 10 ms.
2363 This only takes effect if the memory commands are activated
2364 globally (CONFIG_CMD_MEM).
2366 - CONFIG_SKIP_LOWLEVEL_INIT
2367 - CONFIG_SKIP_RELOCATE_UBOOT
2369 [ARM only] If these variables are defined, then
2370 certain low level initializations (like setting up
2371 the memory controller) are omitted and/or U-Boot does
2372 not relocate itself into RAM.
2373 Normally these variables MUST NOT be defined. The
2374 only exception is when U-Boot is loaded (to RAM) by
2375 some other boot loader or by a debugger which
2376 performs these intializations itself.
2379 Building the Software:
2380 ======================
2382 Building U-Boot has been tested in native PPC environments (on a
2383 PowerBook G3 running LinuxPPC 2000) and in cross environments
2384 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2387 If you are not using a native PPC environment, it is assumed that you
2388 have the GNU cross compiling tools available in your path and named
2389 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2390 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2391 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2394 CROSS_COMPILE = ppc_4xx-
2397 U-Boot is intended to be simple to build. After installing the
2398 sources you must configure U-Boot for one specific board type. This
2403 where "NAME_config" is the name of one of the existing
2404 configurations; see the main Makefile for supported names.
2406 Note: for some board special configuration names may exist; check if
2407 additional information is available from the board vendor; for
2408 instance, the TQM823L systems are available without (standard)
2409 or with LCD support. You can select such additional "features"
2410 when chosing the configuration, i. e.
2413 - will configure for a plain TQM823L, i. e. no LCD support
2415 make TQM823L_LCD_config
2416 - will configure for a TQM823L with U-Boot console on LCD
2421 Finally, type "make all", and you should get some working U-Boot
2422 images ready for download to / installation on your system:
2424 - "u-boot.bin" is a raw binary image
2425 - "u-boot" is an image in ELF binary format
2426 - "u-boot.srec" is in Motorola S-Record format
2428 By default the build is performed locally and the objects are saved
2429 in the source directory. One of the two methods can be used to change
2430 this behavior and build U-Boot to some external directory:
2432 1. Add O= to the make command line invocations:
2434 make O=/tmp/build distclean
2435 make O=/tmp/build NAME_config
2436 make O=/tmp/build all
2438 2. Set environment variable BUILD_DIR to point to the desired location:
2440 export BUILD_DIR=/tmp/build
2445 Note that the command line "O=" setting overrides the BUILD_DIR environment
2449 Please be aware that the Makefiles assume you are using GNU make, so
2450 for instance on NetBSD you might need to use "gmake" instead of
2454 If the system board that you have is not listed, then you will need
2455 to port U-Boot to your hardware platform. To do this, follow these
2458 1. Add a new configuration option for your board to the toplevel
2459 "Makefile" and to the "MAKEALL" script, using the existing
2460 entries as examples. Note that here and at many other places
2461 boards and other names are listed in alphabetical sort order. Please
2463 2. Create a new directory to hold your board specific code. Add any
2464 files you need. In your board directory, you will need at least
2465 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2466 3. Create a new configuration file "include/configs/<board>.h" for
2468 3. If you're porting U-Boot to a new CPU, then also create a new
2469 directory to hold your CPU specific code. Add any files you need.
2470 4. Run "make <board>_config" with your new name.
2471 5. Type "make", and you should get a working "u-boot.srec" file
2472 to be installed on your target system.
2473 6. Debug and solve any problems that might arise.
2474 [Of course, this last step is much harder than it sounds.]
2477 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2478 ==============================================================
2480 If you have modified U-Boot sources (for instance added a new board
2481 or support for new devices, a new CPU, etc.) you are expected to
2482 provide feedback to the other developers. The feedback normally takes
2483 the form of a "patch", i. e. a context diff against a certain (latest
2484 official or latest in CVS) version of U-Boot sources.
2486 But before you submit such a patch, please verify that your modifi-
2487 cation did not break existing code. At least make sure that *ALL* of
2488 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2489 just run the "MAKEALL" script, which will configure and build U-Boot
2490 for ALL supported system. Be warned, this will take a while. You can
2491 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2492 environment variable to the script, i. e. to use the cross tools from
2493 MontaVista's Hard Hat Linux you can type
2495 CROSS_COMPILE=ppc_8xx- MAKEALL
2497 or to build on a native PowerPC system you can type
2499 CROSS_COMPILE=' ' MAKEALL
2501 When using the MAKEALL script, the default behaviour is to build U-Boot
2502 in the source directory. This location can be changed by setting the
2503 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2504 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2505 <source dir>/LOG directory. This default location can be changed by
2506 setting the MAKEALL_LOGDIR environment variable. For example:
2508 export BUILD_DIR=/tmp/build
2509 export MAKEALL_LOGDIR=/tmp/log
2510 CROSS_COMPILE=ppc_8xx- MAKEALL
2512 With the above settings build objects are saved in the /tmp/build, log
2513 files are saved in the /tmp/log and the source tree remains clean during
2514 the whole build process.
2517 See also "U-Boot Porting Guide" below.
2520 Monitor Commands - Overview:
2521 ============================
2523 go - start application at address 'addr'
2524 run - run commands in an environment variable
2525 bootm - boot application image from memory
2526 bootp - boot image via network using BootP/TFTP protocol
2527 tftpboot- boot image via network using TFTP protocol
2528 and env variables "ipaddr" and "serverip"
2529 (and eventually "gatewayip")
2530 rarpboot- boot image via network using RARP/TFTP protocol
2531 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2532 loads - load S-Record file over serial line
2533 loadb - load binary file over serial line (kermit mode)
2535 mm - memory modify (auto-incrementing)
2536 nm - memory modify (constant address)
2537 mw - memory write (fill)
2539 cmp - memory compare
2540 crc32 - checksum calculation
2541 imd - i2c memory display
2542 imm - i2c memory modify (auto-incrementing)
2543 inm - i2c memory modify (constant address)
2544 imw - i2c memory write (fill)
2545 icrc32 - i2c checksum calculation
2546 iprobe - probe to discover valid I2C chip addresses
2547 iloop - infinite loop on address range
2548 isdram - print SDRAM configuration information
2549 sspi - SPI utility commands
2550 base - print or set address offset
2551 printenv- print environment variables
2552 setenv - set environment variables
2553 saveenv - save environment variables to persistent storage
2554 protect - enable or disable FLASH write protection
2555 erase - erase FLASH memory
2556 flinfo - print FLASH memory information
2557 bdinfo - print Board Info structure
2558 iminfo - print header information for application image
2559 coninfo - print console devices and informations
2560 ide - IDE sub-system
2561 loop - infinite loop on address range
2562 loopw - infinite write loop on address range
2563 mtest - simple RAM test
2564 icache - enable or disable instruction cache
2565 dcache - enable or disable data cache
2566 reset - Perform RESET of the CPU
2567 echo - echo args to console
2568 version - print monitor version
2569 help - print online help
2570 ? - alias for 'help'
2573 Monitor Commands - Detailed Description:
2574 ========================================
2578 For now: just type "help <command>".
2581 Environment Variables:
2582 ======================
2584 U-Boot supports user configuration using Environment Variables which
2585 can be made persistent by saving to Flash memory.
2587 Environment Variables are set using "setenv", printed using
2588 "printenv", and saved to Flash using "saveenv". Using "setenv"
2589 without a value can be used to delete a variable from the
2590 environment. As long as you don't save the environment you are
2591 working with an in-memory copy. In case the Flash area containing the
2592 environment is erased by accident, a default environment is provided.
2594 Some configuration options can be set using Environment Variables:
2596 baudrate - see CONFIG_BAUDRATE
2598 bootdelay - see CONFIG_BOOTDELAY
2600 bootcmd - see CONFIG_BOOTCOMMAND
2602 bootargs - Boot arguments when booting an RTOS image
2604 bootfile - Name of the image to load with TFTP
2606 autoload - if set to "no" (any string beginning with 'n'),
2607 "bootp" will just load perform a lookup of the
2608 configuration from the BOOTP server, but not try to
2609 load any image using TFTP
2611 autostart - if set to "yes", an image loaded using the "bootp",
2612 "rarpboot", "tftpboot" or "diskboot" commands will
2613 be automatically started (by internally calling
2616 If set to "no", a standalone image passed to the
2617 "bootm" command will be copied to the load address
2618 (and eventually uncompressed), but NOT be started.
2619 This can be used to load and uncompress arbitrary
2622 i2cfast - (PPC405GP|PPC405EP only)
2623 if set to 'y' configures Linux I2C driver for fast
2624 mode (400kHZ). This environment variable is used in
2625 initialization code. So, for changes to be effective
2626 it must be saved and board must be reset.
2628 initrd_high - restrict positioning of initrd images:
2629 If this variable is not set, initrd images will be
2630 copied to the highest possible address in RAM; this
2631 is usually what you want since it allows for
2632 maximum initrd size. If for some reason you want to
2633 make sure that the initrd image is loaded below the
2634 CFG_BOOTMAPSZ limit, you can set this environment
2635 variable to a value of "no" or "off" or "0".
2636 Alternatively, you can set it to a maximum upper
2637 address to use (U-Boot will still check that it
2638 does not overwrite the U-Boot stack and data).
2640 For instance, when you have a system with 16 MB
2641 RAM, and want to reserve 4 MB from use by Linux,
2642 you can do this by adding "mem=12M" to the value of
2643 the "bootargs" variable. However, now you must make
2644 sure that the initrd image is placed in the first
2645 12 MB as well - this can be done with
2647 setenv initrd_high 00c00000
2649 If you set initrd_high to 0xFFFFFFFF, this is an
2650 indication to U-Boot that all addresses are legal
2651 for the Linux kernel, including addresses in flash
2652 memory. In this case U-Boot will NOT COPY the
2653 ramdisk at all. This may be useful to reduce the
2654 boot time on your system, but requires that this
2655 feature is supported by your Linux kernel.
2657 ipaddr - IP address; needed for tftpboot command
2659 loadaddr - Default load address for commands like "bootp",
2660 "rarpboot", "tftpboot", "loadb" or "diskboot"
2662 loads_echo - see CONFIG_LOADS_ECHO
2664 serverip - TFTP server IP address; needed for tftpboot command
2666 bootretry - see CONFIG_BOOT_RETRY_TIME
2668 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2670 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2672 ethprime - When CONFIG_NET_MULTI is enabled controls which
2673 interface is used first.
2675 ethact - When CONFIG_NET_MULTI is enabled controls which
2676 interface is currently active. For example you
2677 can do the following
2679 => setenv ethact FEC ETHERNET
2680 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2681 => setenv ethact SCC ETHERNET
2682 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2684 netretry - When set to "no" each network operation will
2685 either succeed or fail without retrying.
2686 When set to "once" the network operation will
2687 fail when all the available network interfaces
2688 are tried once without success.
2689 Useful on scripts which control the retry operation
2692 tftpsrcport - If this is set, the value is used for TFTP's
2695 tftpdstport - If this is set, the value is used for TFTP's UDP
2696 destination port instead of the Well Know Port 69.
2698 vlan - When set to a value < 4095 the traffic over
2699 ethernet is encapsulated/received over 802.1q
2702 The following environment variables may be used and automatically
2703 updated by the network boot commands ("bootp" and "rarpboot"),
2704 depending the information provided by your boot server:
2706 bootfile - see above
2707 dnsip - IP address of your Domain Name Server
2708 dnsip2 - IP address of your secondary Domain Name Server
2709 gatewayip - IP address of the Gateway (Router) to use
2710 hostname - Target hostname
2712 netmask - Subnet Mask
2713 rootpath - Pathname of the root filesystem on the NFS server
2714 serverip - see above
2717 There are two special Environment Variables:
2719 serial# - contains hardware identification information such
2720 as type string and/or serial number
2721 ethaddr - Ethernet address
2723 These variables can be set only once (usually during manufacturing of
2724 the board). U-Boot refuses to delete or overwrite these variables
2725 once they have been set once.
2728 Further special Environment Variables:
2730 ver - Contains the U-Boot version string as printed
2731 with the "version" command. This variable is
2732 readonly (see CONFIG_VERSION_VARIABLE).
2735 Please note that changes to some configuration parameters may take
2736 only effect after the next boot (yes, that's just like Windoze :-).
2739 Command Line Parsing:
2740 =====================
2742 There are two different command line parsers available with U-Boot:
2743 the old "simple" one, and the much more powerful "hush" shell:
2745 Old, simple command line parser:
2746 --------------------------------
2748 - supports environment variables (through setenv / saveenv commands)
2749 - several commands on one line, separated by ';'
2750 - variable substitution using "... ${name} ..." syntax
2751 - special characters ('$', ';') can be escaped by prefixing with '\',
2753 setenv bootcmd bootm \${address}
2754 - You can also escape text by enclosing in single apostrophes, for example:
2755 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2760 - similar to Bourne shell, with control structures like
2761 if...then...else...fi, for...do...done; while...do...done,
2762 until...do...done, ...
2763 - supports environment ("global") variables (through setenv / saveenv
2764 commands) and local shell variables (through standard shell syntax
2765 "name=value"); only environment variables can be used with "run"
2771 (1) If a command line (or an environment variable executed by a "run"
2772 command) contains several commands separated by semicolon, and
2773 one of these commands fails, then the remaining commands will be
2776 (2) If you execute several variables with one call to run (i. e.
2777 calling run with a list af variables as arguments), any failing
2778 command will cause "run" to terminate, i. e. the remaining
2779 variables are not executed.
2781 Note for Redundant Ethernet Interfaces:
2782 =======================================
2784 Some boards come with redundant ethernet interfaces; U-Boot supports
2785 such configurations and is capable of automatic selection of a
2786 "working" interface when needed. MAC assignment works as follows:
2788 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2789 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2790 "eth1addr" (=>eth1), "eth2addr", ...
2792 If the network interface stores some valid MAC address (for instance
2793 in SROM), this is used as default address if there is NO correspon-
2794 ding setting in the environment; if the corresponding environment
2795 variable is set, this overrides the settings in the card; that means:
2797 o If the SROM has a valid MAC address, and there is no address in the
2798 environment, the SROM's address is used.
2800 o If there is no valid address in the SROM, and a definition in the
2801 environment exists, then the value from the environment variable is
2804 o If both the SROM and the environment contain a MAC address, and
2805 both addresses are the same, this MAC address is used.
2807 o If both the SROM and the environment contain a MAC address, and the
2808 addresses differ, the value from the environment is used and a
2811 o If neither SROM nor the environment contain a MAC address, an error
2818 The "boot" commands of this monitor operate on "image" files which
2819 can be basicly anything, preceeded by a special header; see the
2820 definitions in include/image.h for details; basicly, the header
2821 defines the following image properties:
2823 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2824 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2825 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2826 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2827 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2828 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2829 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2830 * Compression Type (uncompressed, gzip, bzip2)
2836 The header is marked by a special Magic Number, and both the header
2837 and the data portions of the image are secured against corruption by
2844 Although U-Boot should support any OS or standalone application
2845 easily, the main focus has always been on Linux during the design of
2848 U-Boot includes many features that so far have been part of some
2849 special "boot loader" code within the Linux kernel. Also, any
2850 "initrd" images to be used are no longer part of one big Linux image;
2851 instead, kernel and "initrd" are separate images. This implementation
2852 serves several purposes:
2854 - the same features can be used for other OS or standalone
2855 applications (for instance: using compressed images to reduce the
2856 Flash memory footprint)
2858 - it becomes much easier to port new Linux kernel versions because
2859 lots of low-level, hardware dependent stuff are done by U-Boot
2861 - the same Linux kernel image can now be used with different "initrd"
2862 images; of course this also means that different kernel images can
2863 be run with the same "initrd". This makes testing easier (you don't
2864 have to build a new "zImage.initrd" Linux image when you just
2865 change a file in your "initrd"). Also, a field-upgrade of the
2866 software is easier now.
2872 Porting Linux to U-Boot based systems:
2873 ---------------------------------------
2875 U-Boot cannot save you from doing all the necessary modifications to
2876 configure the Linux device drivers for use with your target hardware
2877 (no, we don't intend to provide a full virtual machine interface to
2880 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2882 Just make sure your machine specific header file (for instance
2883 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2884 Information structure as we define in include/u-boot.h, and make
2885 sure that your definition of IMAP_ADDR uses the same value as your
2886 U-Boot configuration in CFG_IMMR.
2889 Configuring the Linux kernel:
2890 -----------------------------
2892 No specific requirements for U-Boot. Make sure you have some root
2893 device (initial ramdisk, NFS) for your target system.
2896 Building a Linux Image:
2897 -----------------------
2899 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2900 not used. If you use recent kernel source, a new build target
2901 "uImage" will exist which automatically builds an image usable by
2902 U-Boot. Most older kernels also have support for a "pImage" target,
2903 which was introduced for our predecessor project PPCBoot and uses a
2904 100% compatible format.
2913 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2914 encapsulate a compressed Linux kernel image with header information,
2915 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2917 * build a standard "vmlinux" kernel image (in ELF binary format):
2919 * convert the kernel into a raw binary image:
2921 ${CROSS_COMPILE}-objcopy -O binary \
2922 -R .note -R .comment \
2923 -S vmlinux linux.bin
2925 * compress the binary image:
2929 * package compressed binary image for U-Boot:
2931 mkimage -A ppc -O linux -T kernel -C gzip \
2932 -a 0 -e 0 -n "Linux Kernel Image" \
2933 -d linux.bin.gz uImage
2936 The "mkimage" tool can also be used to create ramdisk images for use
2937 with U-Boot, either separated from the Linux kernel image, or
2938 combined into one file. "mkimage" encapsulates the images with a 64
2939 byte header containing information about target architecture,
2940 operating system, image type, compression method, entry points, time
2941 stamp, CRC32 checksums, etc.
2943 "mkimage" can be called in two ways: to verify existing images and
2944 print the header information, or to build new images.
2946 In the first form (with "-l" option) mkimage lists the information
2947 contained in the header of an existing U-Boot image; this includes
2948 checksum verification:
2950 tools/mkimage -l image
2951 -l ==> list image header information
2953 The second form (with "-d" option) is used to build a U-Boot image
2954 from a "data file" which is used as image payload:
2956 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2957 -n name -d data_file image
2958 -A ==> set architecture to 'arch'
2959 -O ==> set operating system to 'os'
2960 -T ==> set image type to 'type'
2961 -C ==> set compression type 'comp'
2962 -a ==> set load address to 'addr' (hex)
2963 -e ==> set entry point to 'ep' (hex)
2964 -n ==> set image name to 'name'
2965 -d ==> use image data from 'datafile'
2967 Right now, all Linux kernels for PowerPC systems use the same load
2968 address (0x00000000), but the entry point address depends on the
2971 - 2.2.x kernels have the entry point at 0x0000000C,
2972 - 2.3.x and later kernels have the entry point at 0x00000000.
2974 So a typical call to build a U-Boot image would read:
2976 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2977 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2978 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2979 > examples/uImage.TQM850L
2980 Image Name: 2.4.4 kernel for TQM850L
2981 Created: Wed Jul 19 02:34:59 2000
2982 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2983 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2984 Load Address: 0x00000000
2985 Entry Point: 0x00000000
2987 To verify the contents of the image (or check for corruption):
2989 -> tools/mkimage -l examples/uImage.TQM850L
2990 Image Name: 2.4.4 kernel for TQM850L
2991 Created: Wed Jul 19 02:34:59 2000
2992 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2993 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2994 Load Address: 0x00000000
2995 Entry Point: 0x00000000
2997 NOTE: for embedded systems where boot time is critical you can trade
2998 speed for memory and install an UNCOMPRESSED image instead: this
2999 needs more space in Flash, but boots much faster since it does not
3000 need to be uncompressed:
3002 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3003 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3004 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3005 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3006 > examples/uImage.TQM850L-uncompressed
3007 Image Name: 2.4.4 kernel for TQM850L
3008 Created: Wed Jul 19 02:34:59 2000
3009 Image Type: PowerPC Linux Kernel Image (uncompressed)
3010 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3011 Load Address: 0x00000000
3012 Entry Point: 0x00000000
3015 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3016 when your kernel is intended to use an initial ramdisk:
3018 -> tools/mkimage -n 'Simple Ramdisk Image' \
3019 > -A ppc -O linux -T ramdisk -C gzip \
3020 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3021 Image Name: Simple Ramdisk Image
3022 Created: Wed Jan 12 14:01:50 2000
3023 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3024 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3025 Load Address: 0x00000000
3026 Entry Point: 0x00000000
3029 Installing a Linux Image:
3030 -------------------------
3032 To downloading a U-Boot image over the serial (console) interface,
3033 you must convert the image to S-Record format:
3035 objcopy -I binary -O srec examples/image examples/image.srec
3037 The 'objcopy' does not understand the information in the U-Boot
3038 image header, so the resulting S-Record file will be relative to
3039 address 0x00000000. To load it to a given address, you need to
3040 specify the target address as 'offset' parameter with the 'loads'
3043 Example: install the image to address 0x40100000 (which on the
3044 TQM8xxL is in the first Flash bank):
3046 => erase 40100000 401FFFFF
3052 ## Ready for S-Record download ...
3053 ~>examples/image.srec
3054 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3056 15989 15990 15991 15992
3057 [file transfer complete]
3059 ## Start Addr = 0x00000000
3062 You can check the success of the download using the 'iminfo' command;
3063 this includes a checksum verification so you can be sure no data
3064 corruption happened:
3068 ## Checking Image at 40100000 ...
3069 Image Name: 2.2.13 for initrd on TQM850L
3070 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3071 Data Size: 335725 Bytes = 327 kB = 0 MB
3072 Load Address: 00000000
3073 Entry Point: 0000000c
3074 Verifying Checksum ... OK
3080 The "bootm" command is used to boot an application that is stored in
3081 memory (RAM or Flash). In case of a Linux kernel image, the contents
3082 of the "bootargs" environment variable is passed to the kernel as
3083 parameters. You can check and modify this variable using the
3084 "printenv" and "setenv" commands:
3087 => printenv bootargs
3088 bootargs=root=/dev/ram
3090 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3092 => printenv bootargs
3093 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3096 ## Booting Linux kernel at 40020000 ...
3097 Image Name: 2.2.13 for NFS on TQM850L
3098 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3099 Data Size: 381681 Bytes = 372 kB = 0 MB
3100 Load Address: 00000000
3101 Entry Point: 0000000c
3102 Verifying Checksum ... OK
3103 Uncompressing Kernel Image ... OK
3104 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
3105 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3106 time_init: decrementer frequency = 187500000/60
3107 Calibrating delay loop... 49.77 BogoMIPS
3108 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3111 If you want to boot a Linux kernel with initial ram disk, you pass
3112 the memory addresses of both the kernel and the initrd image (PPBCOOT
3113 format!) to the "bootm" command:
3115 => imi 40100000 40200000
3117 ## Checking Image at 40100000 ...
3118 Image Name: 2.2.13 for initrd on TQM850L
3119 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3120 Data Size: 335725 Bytes = 327 kB = 0 MB
3121 Load Address: 00000000
3122 Entry Point: 0000000c
3123 Verifying Checksum ... OK
3125 ## Checking Image at 40200000 ...
3126 Image Name: Simple Ramdisk Image
3127 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3128 Data Size: 566530 Bytes = 553 kB = 0 MB
3129 Load Address: 00000000
3130 Entry Point: 00000000
3131 Verifying Checksum ... OK
3133 => bootm 40100000 40200000
3134 ## Booting Linux kernel at 40100000 ...
3135 Image Name: 2.2.13 for initrd on TQM850L
3136 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3137 Data Size: 335725 Bytes = 327 kB = 0 MB
3138 Load Address: 00000000
3139 Entry Point: 0000000c
3140 Verifying Checksum ... OK
3141 Uncompressing Kernel Image ... OK
3142 ## Loading RAMDisk Image at 40200000 ...
3143 Image Name: Simple Ramdisk Image
3144 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3145 Data Size: 566530 Bytes = 553 kB = 0 MB
3146 Load Address: 00000000
3147 Entry Point: 00000000
3148 Verifying Checksum ... OK
3149 Loading Ramdisk ... OK
3150 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
3151 Boot arguments: root=/dev/ram
3152 time_init: decrementer frequency = 187500000/60
3153 Calibrating delay loop... 49.77 BogoMIPS
3155 RAMDISK: Compressed image found at block 0
3156 VFS: Mounted root (ext2 filesystem).
3160 Boot Linux and pass a flat device tree:
3163 First, U-Boot must be compiled with the appropriate defines. See the section
3164 titled "Linux Kernel Interface" above for a more in depth explanation. The
3165 following is an example of how to start a kernel and pass an updated
3171 oft=oftrees/mpc8540ads.dtb
3172 => tftp $oftaddr $oft
3173 Speed: 1000, full duplex
3175 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3176 Filename 'oftrees/mpc8540ads.dtb'.
3177 Load address: 0x300000
3180 Bytes transferred = 4106 (100a hex)
3181 => tftp $loadaddr $bootfile
3182 Speed: 1000, full duplex
3184 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3186 Load address: 0x200000
3187 Loading:############
3189 Bytes transferred = 1029407 (fb51f hex)
3194 => bootm $loadaddr - $oftaddr
3195 ## Booting image at 00200000 ...
3196 Image Name: Linux-2.6.17-dirty
3197 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3198 Data Size: 1029343 Bytes = 1005.2 kB
3199 Load Address: 00000000
3200 Entry Point: 00000000
3201 Verifying Checksum ... OK
3202 Uncompressing Kernel Image ... OK
3203 Booting using flat device tree at 0x300000
3204 Using MPC85xx ADS machine description
3205 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3209 More About U-Boot Image Types:
3210 ------------------------------
3212 U-Boot supports the following image types:
3214 "Standalone Programs" are directly runnable in the environment
3215 provided by U-Boot; it is expected that (if they behave
3216 well) you can continue to work in U-Boot after return from
3217 the Standalone Program.
3218 "OS Kernel Images" are usually images of some Embedded OS which
3219 will take over control completely. Usually these programs
3220 will install their own set of exception handlers, device
3221 drivers, set up the MMU, etc. - this means, that you cannot
3222 expect to re-enter U-Boot except by resetting the CPU.
3223 "RAMDisk Images" are more or less just data blocks, and their
3224 parameters (address, size) are passed to an OS kernel that is
3226 "Multi-File Images" contain several images, typically an OS
3227 (Linux) kernel image and one or more data images like
3228 RAMDisks. This construct is useful for instance when you want
3229 to boot over the network using BOOTP etc., where the boot
3230 server provides just a single image file, but you want to get
3231 for instance an OS kernel and a RAMDisk image.
3233 "Multi-File Images" start with a list of image sizes, each
3234 image size (in bytes) specified by an "uint32_t" in network
3235 byte order. This list is terminated by an "(uint32_t)0".
3236 Immediately after the terminating 0 follow the images, one by
3237 one, all aligned on "uint32_t" boundaries (size rounded up to
3238 a multiple of 4 bytes).
3240 "Firmware Images" are binary images containing firmware (like
3241 U-Boot or FPGA images) which usually will be programmed to
3244 "Script files" are command sequences that will be executed by
3245 U-Boot's command interpreter; this feature is especially
3246 useful when you configure U-Boot to use a real shell (hush)
3247 as command interpreter.
3253 One of the features of U-Boot is that you can dynamically load and
3254 run "standalone" applications, which can use some resources of
3255 U-Boot like console I/O functions or interrupt services.
3257 Two simple examples are included with the sources:
3262 'examples/hello_world.c' contains a small "Hello World" Demo
3263 application; it is automatically compiled when you build U-Boot.
3264 It's configured to run at address 0x00040004, so you can play with it
3268 ## Ready for S-Record download ...
3269 ~>examples/hello_world.srec
3270 1 2 3 4 5 6 7 8 9 10 11 ...
3271 [file transfer complete]
3273 ## Start Addr = 0x00040004
3275 => go 40004 Hello World! This is a test.
3276 ## Starting application at 0x00040004 ...
3287 Hit any key to exit ...
3289 ## Application terminated, rc = 0x0
3291 Another example, which demonstrates how to register a CPM interrupt
3292 handler with the U-Boot code, can be found in 'examples/timer.c'.
3293 Here, a CPM timer is set up to generate an interrupt every second.
3294 The interrupt service routine is trivial, just printing a '.'
3295 character, but this is just a demo program. The application can be
3296 controlled by the following keys:
3298 ? - print current values og the CPM Timer registers
3299 b - enable interrupts and start timer
3300 e - stop timer and disable interrupts
3301 q - quit application
3304 ## Ready for S-Record download ...
3305 ~>examples/timer.srec
3306 1 2 3 4 5 6 7 8 9 10 11 ...
3307 [file transfer complete]
3309 ## Start Addr = 0x00040004
3312 ## Starting application at 0x00040004 ...
3315 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3318 [q, b, e, ?] Set interval 1000000 us
3321 [q, b, e, ?] ........
3322 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3325 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3328 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3331 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3333 [q, b, e, ?] ...Stopping timer
3335 [q, b, e, ?] ## Application terminated, rc = 0x0
3341 Over time, many people have reported problems when trying to use the
3342 "minicom" terminal emulation program for serial download. I (wd)
3343 consider minicom to be broken, and recommend not to use it. Under
3344 Unix, I recommend to use C-Kermit for general purpose use (and
3345 especially for kermit binary protocol download ("loadb" command), and
3346 use "cu" for S-Record download ("loads" command).
3348 Nevertheless, if you absolutely want to use it try adding this
3349 configuration to your "File transfer protocols" section:
3351 Name Program Name U/D FullScr IO-Red. Multi
3352 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3353 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3359 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3360 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3362 Building requires a cross environment; it is known to work on
3363 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3364 need gmake since the Makefiles are not compatible with BSD make).
3365 Note that the cross-powerpc package does not install include files;
3366 attempting to build U-Boot will fail because <machine/ansi.h> is
3367 missing. This file has to be installed and patched manually:
3369 # cd /usr/pkg/cross/powerpc-netbsd/include
3371 # ln -s powerpc machine
3372 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3373 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3375 Native builds *don't* work due to incompatibilities between native
3376 and U-Boot include files.
3378 Booting assumes that (the first part of) the image booted is a
3379 stage-2 loader which in turn loads and then invokes the kernel
3380 proper. Loader sources will eventually appear in the NetBSD source
3381 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3382 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3385 Implementation Internals:
3386 =========================
3388 The following is not intended to be a complete description of every
3389 implementation detail. However, it should help to understand the
3390 inner workings of U-Boot and make it easier to port it to custom
3394 Initial Stack, Global Data:
3395 ---------------------------
3397 The implementation of U-Boot is complicated by the fact that U-Boot
3398 starts running out of ROM (flash memory), usually without access to
3399 system RAM (because the memory controller is not initialized yet).
3400 This means that we don't have writable Data or BSS segments, and BSS
3401 is not initialized as zero. To be able to get a C environment working
3402 at all, we have to allocate at least a minimal stack. Implementation
3403 options for this are defined and restricted by the CPU used: Some CPU
3404 models provide on-chip memory (like the IMMR area on MPC8xx and
3405 MPC826x processors), on others (parts of) the data cache can be
3406 locked as (mis-) used as memory, etc.
3408 Chris Hallinan posted a good summary of these issues to the
3409 u-boot-users mailing list:
3411 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3412 From: "Chris Hallinan" <clh@net1plus.com>
3413 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3416 Correct me if I'm wrong, folks, but the way I understand it
3417 is this: Using DCACHE as initial RAM for Stack, etc, does not
3418 require any physical RAM backing up the cache. The cleverness
3419 is that the cache is being used as a temporary supply of
3420 necessary storage before the SDRAM controller is setup. It's
3421 beyond the scope of this list to expain the details, but you
3422 can see how this works by studying the cache architecture and
3423 operation in the architecture and processor-specific manuals.
3425 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3426 is another option for the system designer to use as an
3427 initial stack/ram area prior to SDRAM being available. Either
3428 option should work for you. Using CS 4 should be fine if your
3429 board designers haven't used it for something that would
3430 cause you grief during the initial boot! It is frequently not
3433 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3434 with your processor/board/system design. The default value
3435 you will find in any recent u-boot distribution in
3436 walnut.h should work for you. I'd set it to a value larger
3437 than your SDRAM module. If you have a 64MB SDRAM module, set
3438 it above 400_0000. Just make sure your board has no resources
3439 that are supposed to respond to that address! That code in
3440 start.S has been around a while and should work as is when
3441 you get the config right.
3446 It is essential to remember this, since it has some impact on the C
3447 code for the initialization procedures:
3449 * Initialized global data (data segment) is read-only. Do not attempt
3452 * Do not use any unitialized global data (or implicitely initialized
3453 as zero data - BSS segment) at all - this is undefined, initiali-
3454 zation is performed later (when relocating to RAM).
3456 * Stack space is very limited. Avoid big data buffers or things like
3459 Having only the stack as writable memory limits means we cannot use
3460 normal global data to share information beween the code. But it
3461 turned out that the implementation of U-Boot can be greatly
3462 simplified by making a global data structure (gd_t) available to all
3463 functions. We could pass a pointer to this data as argument to _all_
3464 functions, but this would bloat the code. Instead we use a feature of
3465 the GCC compiler (Global Register Variables) to share the data: we
3466 place a pointer (gd) to the global data into a register which we
3467 reserve for this purpose.
3469 When choosing a register for such a purpose we are restricted by the
3470 relevant (E)ABI specifications for the current architecture, and by
3471 GCC's implementation.
3473 For PowerPC, the following registers have specific use:
3476 R3-R4: parameter passing and return values
3477 R5-R10: parameter passing
3478 R13: small data area pointer
3482 (U-Boot also uses R14 as internal GOT pointer.)
3484 ==> U-Boot will use R29 to hold a pointer to the global data
3486 Note: on PPC, we could use a static initializer (since the
3487 address of the global data structure is known at compile time),
3488 but it turned out that reserving a register results in somewhat
3489 smaller code - although the code savings are not that big (on
3490 average for all boards 752 bytes for the whole U-Boot image,
3491 624 text + 127 data).
3493 On ARM, the following registers are used:
3495 R0: function argument word/integer result
3496 R1-R3: function argument word
3498 R10: stack limit (used only if stack checking if enabled)
3499 R11: argument (frame) pointer
3500 R12: temporary workspace
3503 R15: program counter
3505 ==> U-Boot will use R8 to hold a pointer to the global data
3507 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3508 or current versions of GCC may "optimize" the code too much.
3513 U-Boot runs in system state and uses physical addresses, i.e. the
3514 MMU is not used either for address mapping nor for memory protection.
3516 The available memory is mapped to fixed addresses using the memory
3517 controller. In this process, a contiguous block is formed for each
3518 memory type (Flash, SDRAM, SRAM), even when it consists of several
3519 physical memory banks.
3521 U-Boot is installed in the first 128 kB of the first Flash bank (on
3522 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3523 booting and sizing and initializing DRAM, the code relocates itself
3524 to the upper end of DRAM. Immediately below the U-Boot code some
3525 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3526 configuration setting]. Below that, a structure with global Board
3527 Info data is placed, followed by the stack (growing downward).
3529 Additionally, some exception handler code is copied to the low 8 kB
3530 of DRAM (0x00000000 ... 0x00001FFF).
3532 So a typical memory configuration with 16 MB of DRAM could look like
3535 0x0000 0000 Exception Vector code
3538 0x0000 2000 Free for Application Use
3544 0x00FB FF20 Monitor Stack (Growing downward)
3545 0x00FB FFAC Board Info Data and permanent copy of global data
3546 0x00FC 0000 Malloc Arena
3549 0x00FE 0000 RAM Copy of Monitor Code
3550 ... eventually: LCD or video framebuffer
3551 ... eventually: pRAM (Protected RAM - unchanged by reset)
3552 0x00FF FFFF [End of RAM]
3555 System Initialization:
3556 ----------------------
3558 In the reset configuration, U-Boot starts at the reset entry point
3559 (on most PowerPC systens at address 0x00000100). Because of the reset
3560 configuration for CS0# this is a mirror of the onboard Flash memory.
3561 To be able to re-map memory U-Boot then jumps to its link address.
3562 To be able to implement the initialization code in C, a (small!)
3563 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3564 which provide such a feature like MPC8xx or MPC8260), or in a locked
3565 part of the data cache. After that, U-Boot initializes the CPU core,
3566 the caches and the SIU.
3568 Next, all (potentially) available memory banks are mapped using a
3569 preliminary mapping. For example, we put them on 512 MB boundaries
3570 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3571 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3572 programmed for SDRAM access. Using the temporary configuration, a
3573 simple memory test is run that determines the size of the SDRAM
3576 When there is more than one SDRAM bank, and the banks are of
3577 different size, the largest is mapped first. For equal size, the first
3578 bank (CS2#) is mapped first. The first mapping is always for address
3579 0x00000000, with any additional banks following immediately to create
3580 contiguous memory starting from 0.
3582 Then, the monitor installs itself at the upper end of the SDRAM area
3583 and allocates memory for use by malloc() and for the global Board
3584 Info data; also, the exception vector code is copied to the low RAM
3585 pages, and the final stack is set up.
3587 Only after this relocation will you have a "normal" C environment;
3588 until that you are restricted in several ways, mostly because you are
3589 running from ROM, and because the code will have to be relocated to a
3593 U-Boot Porting Guide:
3594 ----------------------
3596 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3600 int main (int argc, char *argv[])
3602 sighandler_t no_more_time;
3604 signal (SIGALRM, no_more_time);
3605 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3607 if (available_money > available_manpower) {
3608 pay consultant to port U-Boot;
3612 Download latest U-Boot source;
3614 Subscribe to u-boot-users mailing list;
3617 email ("Hi, I am new to U-Boot, how do I get started?");
3621 Read the README file in the top level directory;
3622 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3623 Read the source, Luke;
3626 if (available_money > toLocalCurrency ($2500)) {
3629 Add a lot of aggravation and time;
3632 Create your own board support subdirectory;
3634 Create your own board config file;
3638 Add / modify source code;
3642 email ("Hi, I am having problems...");
3644 Send patch file to Wolfgang;
3649 void no_more_time (int sig)
3658 All contributions to U-Boot should conform to the Linux kernel
3659 coding style; see the file "Documentation/CodingStyle" and the script
3660 "scripts/Lindent" in your Linux kernel source directory. In sources
3661 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3662 spaces before parameters to function calls) is actually used.
3664 Source files originating from a different project (for example the
3665 MTD subsystem) are generally exempt from these guidelines and are not
3666 reformated to ease subsequent migration to newer versions of those
3669 Please note that U-Boot is implemented in C (and to some small parts in
3670 Assembler); no C++ is used, so please do not use C++ style comments (//)
3673 Please also stick to the following formatting rules:
3674 - remove any trailing white space
3675 - use TAB characters for indentation, not spaces
3676 - make sure NOT to use DOS '\r\n' line feeds
3677 - do not add more than 2 empty lines to source files
3678 - do not add trailing empty lines to source files
3680 Submissions which do not conform to the standards may be returned
3681 with a request to reformat the changes.
3687 Since the number of patches for U-Boot is growing, we need to
3688 establish some rules. Submissions which do not conform to these rules
3689 may be rejected, even when they contain important and valuable stuff.
3691 Patches shall be sent to the u-boot-users mailing list.
3693 When you send a patch, please include the following information with
3696 * For bug fixes: a description of the bug and how your patch fixes
3697 this bug. Please try to include a way of demonstrating that the
3698 patch actually fixes something.
3700 * For new features: a description of the feature and your
3703 * A CHANGELOG entry as plaintext (separate from the patch)
3705 * For major contributions, your entry to the CREDITS file
3707 * When you add support for a new board, don't forget to add this
3708 board to the MAKEALL script, too.
3710 * If your patch adds new configuration options, don't forget to
3711 document these in the README file.
3713 * The patch itself. If you are accessing the CVS repository use "cvs
3714 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3715 version of diff does not support these options, then get the latest
3716 version of GNU diff.
3718 The current directory when running this command shall be the top
3719 level directory of the U-Boot source tree, or it's parent directory
3720 (i. e. please make sure that your patch includes sufficient
3721 directory information for the affected files).
3723 We accept patches as plain text, MIME attachments or as uuencoded
3726 * If one logical set of modifications affects or creates several
3727 files, all these changes shall be submitted in a SINGLE patch file.
3729 * Changesets that contain different, unrelated modifications shall be
3730 submitted as SEPARATE patches, one patch per changeset.
3735 * Before sending the patch, run the MAKEALL script on your patched
3736 source tree and make sure that no errors or warnings are reported
3737 for any of the boards.
3739 * Keep your modifications to the necessary minimum: A patch
3740 containing several unrelated changes or arbitrary reformats will be
3741 returned with a request to re-formatting / split it.
3743 * If you modify existing code, make sure that your new code does not
3744 add to the memory footprint of the code ;-) Small is beautiful!
3745 When adding new features, these should compile conditionally only
3746 (using #ifdef), and the resulting code with the new feature
3747 disabled must not need more memory than the old code without your
3750 * Remember that there is a size limit of 40 kB per message on the
3751 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob