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 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
141 - mips Files specific to MIPS CPUs
142 - mpc5xx Files specific to Freescale MPC5xx CPUs
143 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
144 - mpc8xx Files specific to Freescale MPC8xx CPUs
145 - mpc8220 Files specific to Freescale MPC8220 CPUs
146 - mpc824x Files specific to Freescale MPC824x CPUs
147 - mpc8260 Files specific to Freescale MPC8260 CPUs
148 - mpc85xx Files specific to Freescale MPC85xx CPUs
149 - nios Files specific to Altera NIOS CPUs
150 - nios2 Files specific to Altera Nios-II CPUs
151 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
152 - pxa Files specific to Intel XScale PXA CPUs
153 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
154 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
155 - disk Code for disk drive partition handling
156 - doc Documentation (don't expect too much)
157 - drivers Commonly used device drivers
158 - dtt Digital Thermometer and Thermostat drivers
159 - examples Example code for standalone applications, etc.
160 - include Header Files
161 - lib_arm Files generic to ARM architecture
162 - lib_avr32 Files generic to AVR32 architecture
163 - lib_generic Files generic to all architectures
164 - lib_i386 Files generic to i386 architecture
165 - lib_m68k Files generic to m68k architecture
166 - lib_mips Files generic to MIPS architecture
167 - lib_nios Files generic to NIOS architecture
168 - lib_ppc Files generic to PowerPC architecture
169 - libfdt Library files to support flattened device trees
170 - net Networking code
171 - post Power On Self Test
172 - rtc Real Time Clock drivers
173 - tools Tools to build S-Record or U-Boot images, etc.
175 Software Configuration:
176 =======================
178 Configuration is usually done using C preprocessor defines; the
179 rationale behind that is to avoid dead code whenever possible.
181 There are two classes of configuration variables:
183 * Configuration _OPTIONS_:
184 These are selectable by the user and have names beginning with
187 * Configuration _SETTINGS_:
188 These depend on the hardware etc. and should not be meddled with if
189 you don't know what you're doing; they have names beginning with
192 Later we will add a configuration tool - probably similar to or even
193 identical to what's used for the Linux kernel. Right now, we have to
194 do the configuration by hand, which means creating some symbolic
195 links and editing some configuration files. We use the TQM8xxL boards
199 Selection of Processor Architecture and Board Type:
200 ---------------------------------------------------
202 For all supported boards there are ready-to-use default
203 configurations available; just type "make <board_name>_config".
205 Example: For a TQM823L module type:
210 For the Cogent platform, you need to specify the cpu type as well;
211 e.g. "make cogent_mpc8xx_config". And also configure the cogent
212 directory according to the instructions in cogent/README.
215 Configuration Options:
216 ----------------------
218 Configuration depends on the combination of board and CPU type; all
219 such information is kept in a configuration file
220 "include/configs/<board_name>.h".
222 Example: For a TQM823L module, all configuration settings are in
223 "include/configs/TQM823L.h".
226 Many of the options are named exactly as the corresponding Linux
227 kernel configuration options. The intention is to make it easier to
228 build a config tool - later.
231 The following options need to be configured:
233 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
235 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
237 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
238 Define exactly one of
242 - CPU Module Type: (if CONFIG_COGENT is defined)
243 Define exactly one of
245 --- FIXME --- not tested yet:
246 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
247 CONFIG_CMA287_23, CONFIG_CMA287_50
249 - Motherboard Type: (if CONFIG_COGENT is defined)
250 Define exactly one of
251 CONFIG_CMA101, CONFIG_CMA102
253 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
254 Define one or more of
257 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
258 Define one or more of
259 CONFIG_LCD_HEARTBEAT - update a character position on
260 the lcd display every second with
263 - Board flavour: (if CONFIG_MPC8260ADS is defined)
266 CFG_8260ADS - original MPC8260ADS
267 CFG_8266ADS - MPC8266ADS
268 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
269 CFG_8272ADS - MPC8272ADS
271 - MPC824X Family Member (if CONFIG_MPC824X is defined)
272 Define exactly one of
273 CONFIG_MPC8240, CONFIG_MPC8245
275 - 8xx CPU Options: (if using an MPC8xx cpu)
276 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
277 get_gclk_freq() cannot work
278 e.g. if there is no 32KHz
279 reference PIT/RTC clock
280 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
283 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
286 CONFIG_8xx_CPUCLK_DEFAULT
287 See doc/README.MPC866
291 Define this to measure the actual CPU clock instead
292 of relying on the correctness of the configured
293 values. Mostly useful for board bringup to make sure
294 the PLL is locked at the intended frequency. Note
295 that this requires a (stable) reference clock (32 kHz
296 RTC clock or CFG_8XX_XIN)
298 - Intel Monahans options:
299 CFG_MONAHANS_RUN_MODE_OSC_RATIO
301 Defines the Monahans run mode to oscillator
302 ratio. Valid values are 8, 16, 24, 31. The core
303 frequency is this value multiplied by 13 MHz.
305 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
307 Defines the Monahans turbo mode to oscillator
308 ratio. Valid values are 1 (default if undefined) and
309 2. The core frequency as calculated above is multiplied
312 - Linux Kernel Interface:
315 U-Boot stores all clock information in Hz
316 internally. For binary compatibility with older Linux
317 kernels (which expect the clocks passed in the
318 bd_info data to be in MHz) the environment variable
319 "clocks_in_mhz" can be defined so that U-Boot
320 converts clock data to MHZ before passing it to the
322 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
323 "clocks_in_mhz=1" is automatically included in the
326 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
328 When transfering memsize parameter to linux, some versions
329 expect it to be in bytes, others in MB.
330 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
332 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
334 New kernel versions are expecting firmware settings to be
335 passed using flattened device trees (based on open firmware
339 * New libfdt-based support
340 * Adds the "fdt" command
341 * The bootm command does _not_ modify the fdt
344 * Deprecated, see CONFIG_OF_LIBFDT
345 * Original ft_build.c-based support
346 * Automatically modifies the dft as part of the bootm command
347 * The environment variable "disable_of", when set,
348 disables this functionality.
350 CONFIG_OF_FLAT_TREE_MAX_SIZE
352 The maximum size of the constructed OF tree.
354 OF_CPU - The proper name of the cpus node.
355 OF_SOC - The proper name of the soc node.
356 OF_TBCLK - The timebase frequency.
357 OF_STDOUT_PATH - The path to the console device
361 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
362 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
363 will have a copy of the bd_t. Space should be
364 pre-allocated in the dts for the bd_t.
366 CONFIG_OF_HAS_UBOOT_ENV
368 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
369 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
370 will have a copy of u-boot's environment variables
372 CONFIG_OF_BOARD_SETUP
374 Board code has addition modification that it wants to make
375 to the flat device tree before handing it off to the kernel
379 This define fills in the correct boot cpu in the boot
380 param header, the default value is zero if undefined.
385 Define this if you want support for Amba PrimeCell PL010 UARTs.
389 Define this if you want support for Amba PrimeCell PL011 UARTs.
393 If you have Amba PrimeCell PL011 UARTs, set this variable to
394 the clock speed of the UARTs.
398 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
399 define this to a list of base addresses for each (supported)
400 port. See e.g. include/configs/versatile.h
404 Depending on board, define exactly one serial port
405 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
406 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
407 console by defining CONFIG_8xx_CONS_NONE
409 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
410 port routines must be defined elsewhere
411 (i.e. serial_init(), serial_getc(), ...)
414 Enables console device for a color framebuffer. Needs following
415 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
416 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
418 VIDEO_HW_RECTFILL graphic chip supports
421 VIDEO_HW_BITBLT graphic chip supports
422 bit-blit (cf. smiLynxEM)
423 VIDEO_VISIBLE_COLS visible pixel columns
425 VIDEO_VISIBLE_ROWS visible pixel rows
426 VIDEO_PIXEL_SIZE bytes per pixel
427 VIDEO_DATA_FORMAT graphic data format
428 (0-5, cf. cfb_console.c)
429 VIDEO_FB_ADRS framebuffer address
430 VIDEO_KBD_INIT_FCT keyboard int fct
431 (i.e. i8042_kbd_init())
432 VIDEO_TSTC_FCT test char fct
434 VIDEO_GETC_FCT get char fct
436 CONFIG_CONSOLE_CURSOR cursor drawing on/off
437 (requires blink timer
439 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
440 CONFIG_CONSOLE_TIME display time/date info in
442 (requires CONFIG_CMD_DATE)
443 CONFIG_VIDEO_LOGO display Linux logo in
445 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
446 linux_logo.h for logo.
447 Requires CONFIG_VIDEO_LOGO
448 CONFIG_CONSOLE_EXTRA_INFO
449 addional board info beside
452 When CONFIG_CFB_CONSOLE is defined, video console is
453 default i/o. Serial console can be forced with
454 environment 'console=serial'.
456 When CONFIG_SILENT_CONSOLE is defined, all console
457 messages (by U-Boot and Linux!) can be silenced with
458 the "silent" environment variable. See
459 doc/README.silent for more information.
462 CONFIG_BAUDRATE - in bps
463 Select one of the baudrates listed in
464 CFG_BAUDRATE_TABLE, see below.
465 CFG_BRGCLK_PRESCALE, baudrate prescale
467 - Interrupt driven serial port input:
468 CONFIG_SERIAL_SOFTWARE_FIFO
471 Use an interrupt handler for receiving data on the
472 serial port. It also enables using hardware handshake
473 (RTS/CTS) and UART's built-in FIFO. Set the number of
474 bytes the interrupt driven input buffer should have.
476 Leave undefined to disable this feature, including
477 disable the buffer and hardware handshake.
479 - Console UART Number:
483 If defined internal UART1 (and not UART0) is used
484 as default U-Boot console.
486 - Boot Delay: CONFIG_BOOTDELAY - in seconds
487 Delay before automatically booting the default image;
488 set to -1 to disable autoboot.
490 See doc/README.autoboot for these options that
491 work with CONFIG_BOOTDELAY. None are required.
492 CONFIG_BOOT_RETRY_TIME
493 CONFIG_BOOT_RETRY_MIN
494 CONFIG_AUTOBOOT_KEYED
495 CONFIG_AUTOBOOT_PROMPT
496 CONFIG_AUTOBOOT_DELAY_STR
497 CONFIG_AUTOBOOT_STOP_STR
498 CONFIG_AUTOBOOT_DELAY_STR2
499 CONFIG_AUTOBOOT_STOP_STR2
500 CONFIG_ZERO_BOOTDELAY_CHECK
501 CONFIG_RESET_TO_RETRY
505 Only needed when CONFIG_BOOTDELAY is enabled;
506 define a command string that is automatically executed
507 when no character is read on the console interface
508 within "Boot Delay" after reset.
511 This can be used to pass arguments to the bootm
512 command. The value of CONFIG_BOOTARGS goes into the
513 environment value "bootargs".
515 CONFIG_RAMBOOT and CONFIG_NFSBOOT
516 The value of these goes into the environment as
517 "ramboot" and "nfsboot" respectively, and can be used
518 as a convenience, when switching between booting from
524 When this option is #defined, the existence of the
525 environment variable "preboot" will be checked
526 immediately before starting the CONFIG_BOOTDELAY
527 countdown and/or running the auto-boot command resp.
528 entering interactive mode.
530 This feature is especially useful when "preboot" is
531 automatically generated or modified. For an example
532 see the LWMON board specific code: here "preboot" is
533 modified when the user holds down a certain
534 combination of keys on the (special) keyboard when
537 - Serial Download Echo Mode:
539 If defined to 1, all characters received during a
540 serial download (using the "loads" command) are
541 echoed back. This might be needed by some terminal
542 emulations (like "cu"), but may as well just take
543 time on others. This setting #define's the initial
544 value of the "loads_echo" environment variable.
546 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
548 Select one of the baudrates listed in
549 CFG_BAUDRATE_TABLE, see below.
552 Monitor commands can be included or excluded
553 from the build by using the #include files
554 "config_cmd_all.h" and #undef'ing unwanted
555 commands, or using "config_cmd_default.h"
556 and augmenting with additional #define's
559 The default command configuration includes all commands
560 except those marked below with a "*".
562 CONFIG_CMD_ASKENV * ask for env variable
563 CONFIG_CMD_AUTOSCRIPT Autoscript Support
564 CONFIG_CMD_BDI bdinfo
565 CONFIG_CMD_BEDBUG * Include BedBug Debugger
566 CONFIG_CMD_BMP * BMP support
567 CONFIG_CMD_BSP * Board specific commands
568 CONFIG_CMD_BOOTD bootd
569 CONFIG_CMD_CACHE * icache, dcache
570 CONFIG_CMD_CONSOLE coninfo
571 CONFIG_CMD_DATE * support for RTC, date/time...
572 CONFIG_CMD_DHCP * DHCP support
573 CONFIG_CMD_DIAG * Diagnostics
574 CONFIG_CMD_DOC * Disk-On-Chip Support
575 CONFIG_CMD_DTT * Digital Therm and Thermostat
576 CONFIG_CMD_ECHO echo arguments
577 CONFIG_CMD_EEPROM * EEPROM read/write support
578 CONFIG_CMD_ELF * bootelf, bootvx
579 CONFIG_CMD_ENV saveenv
580 CONFIG_CMD_FDC * Floppy Disk Support
581 CONFIG_CMD_FAT * FAT partition support
582 CONFIG_CMD_FDOS * Dos diskette Support
583 CONFIG_CMD_FLASH flinfo, erase, protect
584 CONFIG_CMD_FPGA FPGA device initialization support
585 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
586 CONFIG_CMD_I2C * I2C serial bus support
587 CONFIG_CMD_IDE * IDE harddisk support
588 CONFIG_CMD_IMI iminfo
589 CONFIG_CMD_IMLS List all found images
590 CONFIG_CMD_IMMAP * IMMR dump support
591 CONFIG_CMD_IRQ * irqinfo
592 CONFIG_CMD_ITEST Integer/string test of 2 values
593 CONFIG_CMD_JFFS2 * JFFS2 Support
594 CONFIG_CMD_KGDB * kgdb
595 CONFIG_CMD_LOADB loadb
596 CONFIG_CMD_LOADS loads
597 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
599 CONFIG_CMD_MISC Misc functions like sleep etc
600 CONFIG_CMD_MMC * MMC memory mapped support
601 CONFIG_CMD_MII * MII utility commands
602 CONFIG_CMD_NAND * NAND support
603 CONFIG_CMD_NET bootp, tftpboot, rarpboot
604 CONFIG_CMD_PCI * pciinfo
605 CONFIG_CMD_PCMCIA * PCMCIA support
606 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
608 CONFIG_CMD_PORTIO * Port I/O
609 CONFIG_CMD_REGINFO * Register dump
610 CONFIG_CMD_RUN run command in env variable
611 CONFIG_CMD_SAVES * save S record dump
612 CONFIG_CMD_SCSI * SCSI Support
613 CONFIG_CMD_SDRAM * print SDRAM configuration information
614 (requires CONFIG_CMD_I2C)
615 CONFIG_CMD_SETGETDCR Support for DCR Register access
617 CONFIG_CMD_SPI * SPI serial bus support
618 CONFIG_CMD_USB * USB support
619 CONFIG_CMD_VFD * VFD support (TRAB)
620 CONFIG_CMD_BSP * Board SPecific functions
621 CONFIG_CMD_CDP * Cisco Discover Protocol support
622 CONFIG_CMD_FSL * Microblaze FSL support
625 EXAMPLE: If you want all functions except of network
626 support you can write:
628 #include "config_cmd_all.h"
629 #undef CONFIG_CMD_NET
632 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
634 Note: Don't enable the "icache" and "dcache" commands
635 (configuration option CONFIG_CMD_CACHE) unless you know
636 what you (and your U-Boot users) are doing. Data
637 cache cannot be enabled on systems like the 8xx or
638 8260 (where accesses to the IMMR region must be
639 uncached), and it cannot be disabled on all other
640 systems where we (mis-) use the data cache to hold an
641 initial stack and some data.
644 XXX - this list needs to get updated!
648 If this variable is defined, it enables watchdog
649 support. There must be support in the platform specific
650 code for a watchdog. For the 8xx and 8260 CPUs, the
651 SIU Watchdog feature is enabled in the SYPCR
655 CONFIG_VERSION_VARIABLE
656 If this variable is defined, an environment variable
657 named "ver" is created by U-Boot showing the U-Boot
658 version as printed by the "version" command.
659 This variable is readonly.
663 When CONFIG_CMD_DATE is selected, the type of the RTC
664 has to be selected, too. Define exactly one of the
667 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
668 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
669 CONFIG_RTC_MC146818 - use MC146818 RTC
670 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
671 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
672 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
673 CONFIG_RTC_DS164x - use Dallas DS164x RTC
674 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
676 Note that if the RTC uses I2C, then the I2C interface
677 must also be configured. See I2C Support, below.
681 When CONFIG_TIMESTAMP is selected, the timestamp
682 (date and time) of an image is printed by image
683 commands like bootm or iminfo. This option is
684 automatically enabled when you select CONFIG_CMD_DATE .
687 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
688 and/or CONFIG_ISO_PARTITION
690 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
691 CONFIG_CMD_SCSI) you must configure support for at least
692 one partition type as well.
695 CONFIG_IDE_RESET_ROUTINE - this is defined in several
696 board configurations files but used nowhere!
698 CONFIG_IDE_RESET - is this is defined, IDE Reset will
699 be performed by calling the function
700 ide_set_reset(int reset)
701 which has to be defined in a board specific file
706 Set this to enable ATAPI support.
711 Set this to enable support for disks larger than 137GB
712 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
713 Whithout these , LBA48 support uses 32bit variables and will 'only'
714 support disks up to 2.1TB.
717 When enabled, makes the IDE subsystem use 64bit sector addresses.
721 At the moment only there is only support for the
722 SYM53C8XX SCSI controller; define
723 CONFIG_SCSI_SYM53C8XX to enable it.
725 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
726 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
727 CFG_SCSI_MAX_LUN] can be adjusted to define the
728 maximum numbers of LUNs, SCSI ID's and target
730 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
732 - NETWORK Support (PCI):
734 Support for Intel 8254x gigabit chips.
737 Support for Intel 82557/82559/82559ER chips.
738 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
739 write routine for first time initialisation.
742 Support for Digital 2114x chips.
743 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
744 modem chip initialisation (KS8761/QS6611).
747 Support for National dp83815 chips.
750 Support for National dp8382[01] gigabit chips.
752 - NETWORK Support (other):
754 CONFIG_DRIVER_LAN91C96
755 Support for SMSC's LAN91C96 chips.
758 Define this to hold the physical address
759 of the LAN91C96's I/O space
761 CONFIG_LAN91C96_USE_32_BIT
762 Define this to enable 32 bit addressing
764 CONFIG_DRIVER_SMC91111
765 Support for SMSC's LAN91C111 chip
768 Define this to hold the physical address
769 of the device (I/O space)
771 CONFIG_SMC_USE_32_BIT
772 Define this if data bus is 32 bits
774 CONFIG_SMC_USE_IOFUNCS
775 Define this to use i/o functions instead of macros
776 (some hardware wont work with macros)
779 At the moment only the UHCI host controller is
780 supported (PIP405, MIP405, MPC5200); define
781 CONFIG_USB_UHCI to enable it.
782 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
783 and define CONFIG_USB_STORAGE to enable the USB
786 Supported are USB Keyboards and USB Floppy drives
788 MPC5200 USB requires additional defines:
790 for 528 MHz Clock: 0x0001bbbb
792 for differential drivers: 0x00001000
793 for single ended drivers: 0x00005000
795 May be defined to allow interrupt polling
796 instead of using asynchronous interrupts
799 Define the below if you wish to use the USB console.
800 Once firmware is rebuilt from a serial console issue the
801 command "setenv stdin usbtty; setenv stdout usbtty" and
802 attach your usb cable. The Unix command "dmesg" should print
803 it has found a new device. The environment variable usbtty
804 can be set to gserial or cdc_acm to enable your device to
805 appear to a USB host as a Linux gserial device or a
806 Common Device Class Abstract Control Model serial device.
807 If you select usbtty = gserial you should be able to enumerate
809 # modprobe usbserial vendor=0xVendorID product=0xProductID
810 else if using cdc_acm, simply setting the environment
811 variable usbtty to be cdc_acm should suffice. The following
812 might be defined in YourBoardName.h
815 Define this to build a UDC device
818 Define this to have a tty type of device available to
819 talk to the UDC device
821 CFG_CONSOLE_IS_IN_ENV
822 Define this if you want stdin, stdout &/or stderr to
826 CFG_USB_EXTC_CLK 0xBLAH
827 Derive USB clock from external clock "blah"
828 - CFG_USB_EXTC_CLK 0x02
830 CFG_USB_BRG_CLK 0xBLAH
831 Derive USB clock from brgclk
832 - CFG_USB_BRG_CLK 0x04
834 If you have a USB-IF assigned VendorID then you may wish to
835 define your own vendor specific values either in BoardName.h
836 or directly in usbd_vendor_info.h. If you don't define
837 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
838 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
839 should pretend to be a Linux device to it's target host.
841 CONFIG_USBD_MANUFACTURER
842 Define this string as the name of your company for
843 - CONFIG_USBD_MANUFACTURER "my company"
845 CONFIG_USBD_PRODUCT_NAME
846 Define this string as the name of your product
847 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
850 Define this as your assigned Vendor ID from the USB
851 Implementors Forum. This *must* be a genuine Vendor ID
852 to avoid polluting the USB namespace.
853 - CONFIG_USBD_VENDORID 0xFFFF
855 CONFIG_USBD_PRODUCTID
856 Define this as the unique Product ID
858 - CONFIG_USBD_PRODUCTID 0xFFFF
862 The MMC controller on the Intel PXA is supported. To
863 enable this define CONFIG_MMC. The MMC can be
864 accessed from the boot prompt by mapping the device
865 to physical memory similar to flash. Command line is
866 enabled with CONFIG_CMD_MMC. The MMC driver also works with
867 the FAT fs. This is enabled with CONFIG_CMD_FAT.
869 - Journaling Flash filesystem support:
870 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
871 CONFIG_JFFS2_NAND_DEV
872 Define these for a default partition on a NAND device
874 CFG_JFFS2_FIRST_SECTOR,
875 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
876 Define these for a default partition on a NOR device
879 Define this to create an own partition. You have to provide a
880 function struct part_info* jffs2_part_info(int part_num)
882 If you define only one JFFS2 partition you may also want to
883 #define CFG_JFFS_SINGLE_PART 1
884 to disable the command chpart. This is the default when you
885 have not defined a custom partition
890 Define this to enable standard (PC-Style) keyboard
894 Standard PC keyboard driver with US (is default) and
895 GERMAN key layout (switch via environment 'keymap=de') support.
896 Export function i8042_kbd_init, i8042_tstc and i8042_getc
897 for cfb_console. Supports cursor blinking.
902 Define this to enable video support (for output to
907 Enable Chips & Technologies 69000 Video chip
909 CONFIG_VIDEO_SMI_LYNXEM
910 Enable Silicon Motion SMI 712/710/810 Video chip. The
911 video output is selected via environment 'videoout'
912 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
915 For the CT69000 and SMI_LYNXEM drivers, videomode is
916 selected via environment 'videomode'. Two diferent ways
918 - "videomode=num" 'num' is a standard LiLo mode numbers.
919 Following standard modes are supported (* is default):
921 Colors 640x480 800x600 1024x768 1152x864 1280x1024
922 -------------+---------------------------------------------
923 8 bits | 0x301* 0x303 0x305 0x161 0x307
924 15 bits | 0x310 0x313 0x316 0x162 0x319
925 16 bits | 0x311 0x314 0x317 0x163 0x31A
926 24 bits | 0x312 0x315 0x318 ? 0x31B
927 -------------+---------------------------------------------
928 (i.e. setenv videomode 317; saveenv; reset;)
930 - "videomode=bootargs" all the video parameters are parsed
931 from the bootargs. (See drivers/videomodes.c)
934 CONFIG_VIDEO_SED13806
935 Enable Epson SED13806 driver. This driver supports 8bpp
936 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
937 or CONFIG_VIDEO_SED13806_16BPP
942 Define this to enable a custom keyboard support.
943 This simply calls drv_keyboard_init() which must be
944 defined in your board-specific files.
945 The only board using this so far is RBC823.
947 - LCD Support: CONFIG_LCD
949 Define this to enable LCD support (for output to LCD
950 display); also select one of the supported displays
951 by defining one of these:
953 CONFIG_NEC_NL6448AC33:
955 NEC NL6448AC33-18. Active, color, single scan.
957 CONFIG_NEC_NL6448BC20
959 NEC NL6448BC20-08. 6.5", 640x480.
960 Active, color, single scan.
962 CONFIG_NEC_NL6448BC33_54
964 NEC NL6448BC33-54. 10.4", 640x480.
965 Active, color, single scan.
969 Sharp 320x240. Active, color, single scan.
970 It isn't 16x9, and I am not sure what it is.
972 CONFIG_SHARP_LQ64D341
974 Sharp LQ64D341 display, 640x480.
975 Active, color, single scan.
979 HLD1045 display, 640x480.
980 Active, color, single scan.
984 Optrex CBL50840-2 NF-FW 99 22 M5
986 Hitachi LMG6912RPFC-00T
990 320x240. Black & white.
992 Normally display is black on white background; define
993 CFG_WHITE_ON_BLACK to get it inverted.
995 - Splash Screen Support: CONFIG_SPLASH_SCREEN
997 If this option is set, the environment is checked for
998 a variable "splashimage". If found, the usual display
999 of logo, copyright and system information on the LCD
1000 is suppressed and the BMP image at the address
1001 specified in "splashimage" is loaded instead. The
1002 console is redirected to the "nulldev", too. This
1003 allows for a "silent" boot where a splash screen is
1004 loaded very quickly after power-on.
1006 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1008 If this option is set, additionally to standard BMP
1009 images, gzipped BMP images can be displayed via the
1010 splashscreen support or the bmp command.
1012 - Compression support:
1015 If this option is set, support for bzip2 compressed
1016 images is included. If not, only uncompressed and gzip
1017 compressed images are supported.
1019 NOTE: the bzip2 algorithm requires a lot of RAM, so
1020 the malloc area (as defined by CFG_MALLOC_LEN) should
1026 The address of PHY on MII bus.
1028 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1030 The clock frequency of the MII bus
1034 If this option is set, support for speed/duplex
1035 detection of Gigabit PHY is included.
1037 CONFIG_PHY_RESET_DELAY
1039 Some PHY like Intel LXT971A need extra delay after
1040 reset before any MII register access is possible.
1041 For such PHY, set this option to the usec delay
1042 required. (minimum 300usec for LXT971A)
1044 CONFIG_PHY_CMD_DELAY (ppc4xx)
1046 Some PHY like Intel LXT971A need extra delay after
1047 command issued before MII status register can be read
1054 Define a default value for ethernet address to use
1055 for the respective ethernet interface, in case this
1056 is not determined automatically.
1061 Define a default value for the IP address to use for
1062 the default ethernet interface, in case this is not
1063 determined through e.g. bootp.
1065 - Server IP address:
1068 Defines a default value for theIP address of a TFTP
1069 server to contact when using the "tftboot" command.
1071 - Multicast TFTP Mode:
1074 Defines whether you want to support multicast TFTP as per
1075 rfc-2090; for example to work with atftp. Lets lots of targets
1076 tftp down the same boot image concurrently. Note: the ethernet
1077 driver in use must provide a function: mcast() to join/leave a
1080 CONFIG_BOOTP_RANDOM_DELAY
1081 - BOOTP Recovery Mode:
1082 CONFIG_BOOTP_RANDOM_DELAY
1084 If you have many targets in a network that try to
1085 boot using BOOTP, you may want to avoid that all
1086 systems send out BOOTP requests at precisely the same
1087 moment (which would happen for instance at recovery
1088 from a power failure, when all systems will try to
1089 boot, thus flooding the BOOTP server. Defining
1090 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1091 inserted before sending out BOOTP requests. The
1092 following delays are inserted then:
1094 1st BOOTP request: delay 0 ... 1 sec
1095 2nd BOOTP request: delay 0 ... 2 sec
1096 3rd BOOTP request: delay 0 ... 4 sec
1098 BOOTP requests: delay 0 ... 8 sec
1100 - DHCP Advanced Options:
1101 You can fine tune the DHCP functionality by defining
1102 CONFIG_BOOTP_* symbols:
1104 CONFIG_BOOTP_SUBNETMASK
1105 CONFIG_BOOTP_GATEWAY
1106 CONFIG_BOOTP_HOSTNAME
1107 CONFIG_BOOTP_NISDOMAIN
1108 CONFIG_BOOTP_BOOTPATH
1109 CONFIG_BOOTP_BOOTFILESIZE
1112 CONFIG_BOOTP_SEND_HOSTNAME
1113 CONFIG_BOOTP_NTPSERVER
1114 CONFIG_BOOTP_TIMEOFFSET
1115 CONFIG_BOOTP_VENDOREX
1117 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1118 environment variable, not the BOOTP server.
1120 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1121 serverip from a DHCP server, it is possible that more
1122 than one DNS serverip is offered to the client.
1123 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1124 serverip will be stored in the additional environment
1125 variable "dnsip2". The first DNS serverip is always
1126 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1129 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1130 to do a dynamic update of a DNS server. To do this, they
1131 need the hostname of the DHCP requester.
1132 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1133 of the "hostname" environment variable is passed as
1134 option 12 to the DHCP server.
1137 CONFIG_CDP_DEVICE_ID
1139 The device id used in CDP trigger frames.
1141 CONFIG_CDP_DEVICE_ID_PREFIX
1143 A two character string which is prefixed to the MAC address
1148 A printf format string which contains the ascii name of
1149 the port. Normally is set to "eth%d" which sets
1150 eth0 for the first ethernet, eth1 for the second etc.
1152 CONFIG_CDP_CAPABILITIES
1154 A 32bit integer which indicates the device capabilities;
1155 0x00000010 for a normal host which does not forwards.
1159 An ascii string containing the version of the software.
1163 An ascii string containing the name of the platform.
1167 A 32bit integer sent on the trigger.
1169 CONFIG_CDP_POWER_CONSUMPTION
1171 A 16bit integer containing the power consumption of the
1172 device in .1 of milliwatts.
1174 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1176 A byte containing the id of the VLAN.
1178 - Status LED: CONFIG_STATUS_LED
1180 Several configurations allow to display the current
1181 status using a LED. For instance, the LED will blink
1182 fast while running U-Boot code, stop blinking as
1183 soon as a reply to a BOOTP request was received, and
1184 start blinking slow once the Linux kernel is running
1185 (supported by a status LED driver in the Linux
1186 kernel). Defining CONFIG_STATUS_LED enables this
1189 - CAN Support: CONFIG_CAN_DRIVER
1191 Defining CONFIG_CAN_DRIVER enables CAN driver support
1192 on those systems that support this (optional)
1193 feature, like the TQM8xxL modules.
1195 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1197 These enable I2C serial bus commands. Defining either of
1198 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1199 include the appropriate I2C driver for the selected cpu.
1201 This will allow you to use i2c commands at the u-boot
1202 command line (as long as you set CONFIG_CMD_I2C in
1203 CONFIG_COMMANDS) and communicate with i2c based realtime
1204 clock chips. See common/cmd_i2c.c for a description of the
1205 command line interface.
1207 CONFIG_I2C_CMD_TREE is a recommended option that places
1208 all I2C commands under a single 'i2c' root command. The
1209 older 'imm', 'imd', 'iprobe' etc. commands are considered
1210 deprecated and may disappear in the future.
1212 CONFIG_HARD_I2C selects a hardware I2C controller.
1214 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1215 bit-banging) driver instead of CPM or similar hardware
1218 There are several other quantities that must also be
1219 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1221 In both cases you will need to define CFG_I2C_SPEED
1222 to be the frequency (in Hz) at which you wish your i2c bus
1223 to run and CFG_I2C_SLAVE to be the address of this node (ie
1224 the cpu's i2c node address).
1226 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1227 sets the cpu up as a master node and so its address should
1228 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1229 p.16-473). So, set CFG_I2C_SLAVE to 0.
1231 That's all that's required for CONFIG_HARD_I2C.
1233 If you use the software i2c interface (CONFIG_SOFT_I2C)
1234 then the following macros need to be defined (examples are
1235 from include/configs/lwmon.h):
1239 (Optional). Any commands necessary to enable the I2C
1240 controller or configure ports.
1242 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1246 (Only for MPC8260 CPU). The I/O port to use (the code
1247 assumes both bits are on the same port). Valid values
1248 are 0..3 for ports A..D.
1252 The code necessary to make the I2C data line active
1253 (driven). If the data line is open collector, this
1256 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1260 The code necessary to make the I2C data line tri-stated
1261 (inactive). If the data line is open collector, this
1264 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1268 Code that returns TRUE if the I2C data line is high,
1271 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1275 If <bit> is TRUE, sets the I2C data line high. If it
1276 is FALSE, it clears it (low).
1278 eg: #define I2C_SDA(bit) \
1279 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1280 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1284 If <bit> is TRUE, sets the I2C clock line high. If it
1285 is FALSE, it clears it (low).
1287 eg: #define I2C_SCL(bit) \
1288 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1289 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1293 This delay is invoked four times per clock cycle so this
1294 controls the rate of data transfer. The data rate thus
1295 is 1 / (I2C_DELAY * 4). Often defined to be something
1298 #define I2C_DELAY udelay(2)
1302 When a board is reset during an i2c bus transfer
1303 chips might think that the current transfer is still
1304 in progress. On some boards it is possible to access
1305 the i2c SCLK line directly, either by using the
1306 processor pin as a GPIO or by having a second pin
1307 connected to the bus. If this option is defined a
1308 custom i2c_init_board() routine in boards/xxx/board.c
1309 is run early in the boot sequence.
1311 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1313 This option enables configuration of bi_iic_fast[] flags
1314 in u-boot bd_info structure based on u-boot environment
1315 variable "i2cfast". (see also i2cfast)
1317 CONFIG_I2C_MULTI_BUS
1319 This option allows the use of multiple I2C buses, each of which
1320 must have a controller. At any point in time, only one bus is
1321 active. To switch to a different bus, use the 'i2c dev' command.
1322 Note that bus numbering is zero-based.
1326 This option specifies a list of I2C devices that will be skipped
1327 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1328 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1329 pairs. Otherwise, specify a 1D array of device addresses
1332 #undef CONFIG_I2C_MULTI_BUS
1333 #define CFG_I2C_NOPROBES {0x50,0x68}
1335 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1337 #define CONFIG_I2C_MULTI_BUS
1338 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1340 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1344 If defined, then this indicates the I2C bus number for DDR SPD.
1345 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1349 If defined, then this indicates the I2C bus number for the RTC.
1350 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1354 If defined, then this indicates the I2C bus number for the DTT.
1355 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1359 Define this option if you want to use Freescale's I2C driver in
1363 - SPI Support: CONFIG_SPI
1365 Enables SPI driver (so far only tested with
1366 SPI EEPROM, also an instance works with Crystal A/D and
1367 D/As on the SACSng board)
1371 Enables extended (16-bit) SPI EEPROM addressing.
1372 (symmetrical to CONFIG_I2C_X)
1376 Enables a software (bit-bang) SPI driver rather than
1377 using hardware support. This is a general purpose
1378 driver that only requires three general I/O port pins
1379 (two outputs, one input) to function. If this is
1380 defined, the board configuration must define several
1381 SPI configuration items (port pins to use, etc). For
1382 an example, see include/configs/sacsng.h.
1384 - FPGA Support: CONFIG_FPGA_COUNT
1386 Specify the number of FPGA devices to support.
1390 Used to specify the types of FPGA devices. For example,
1391 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1393 CFG_FPGA_PROG_FEEDBACK
1395 Enable printing of hash marks during FPGA configuration.
1399 Enable checks on FPGA configuration interface busy
1400 status by the configuration function. This option
1401 will require a board or device specific function to
1406 If defined, a function that provides delays in the FPGA
1407 configuration driver.
1409 CFG_FPGA_CHECK_CTRLC
1410 Allow Control-C to interrupt FPGA configuration
1412 CFG_FPGA_CHECK_ERROR
1414 Check for configuration errors during FPGA bitfile
1415 loading. For example, abort during Virtex II
1416 configuration if the INIT_B line goes low (which
1417 indicated a CRC error).
1421 Maximum time to wait for the INIT_B line to deassert
1422 after PROB_B has been deasserted during a Virtex II
1423 FPGA configuration sequence. The default time is 500
1428 Maximum time to wait for BUSY to deassert during
1429 Virtex II FPGA configuration. The default is 5 mS.
1431 CFG_FPGA_WAIT_CONFIG
1433 Time to wait after FPGA configuration. The default is
1436 - Configuration Management:
1439 If defined, this string will be added to the U-Boot
1440 version information (U_BOOT_VERSION)
1442 - Vendor Parameter Protection:
1444 U-Boot considers the values of the environment
1445 variables "serial#" (Board Serial Number) and
1446 "ethaddr" (Ethernet Address) to be parameters that
1447 are set once by the board vendor / manufacturer, and
1448 protects these variables from casual modification by
1449 the user. Once set, these variables are read-only,
1450 and write or delete attempts are rejected. You can
1451 change this behviour:
1453 If CONFIG_ENV_OVERWRITE is #defined in your config
1454 file, the write protection for vendor parameters is
1455 completely disabled. Anybody can change or delete
1458 Alternatively, if you #define _both_ CONFIG_ETHADDR
1459 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1460 ethernet address is installed in the environment,
1461 which can be changed exactly ONCE by the user. [The
1462 serial# is unaffected by this, i. e. it remains
1468 Define this variable to enable the reservation of
1469 "protected RAM", i. e. RAM which is not overwritten
1470 by U-Boot. Define CONFIG_PRAM to hold the number of
1471 kB you want to reserve for pRAM. You can overwrite
1472 this default value by defining an environment
1473 variable "pram" to the number of kB you want to
1474 reserve. Note that the board info structure will
1475 still show the full amount of RAM. If pRAM is
1476 reserved, a new environment variable "mem" will
1477 automatically be defined to hold the amount of
1478 remaining RAM in a form that can be passed as boot
1479 argument to Linux, for instance like that:
1481 setenv bootargs ... mem=\${mem}
1484 This way you can tell Linux not to use this memory,
1485 either, which results in a memory region that will
1486 not be affected by reboots.
1488 *WARNING* If your board configuration uses automatic
1489 detection of the RAM size, you must make sure that
1490 this memory test is non-destructive. So far, the
1491 following board configurations are known to be
1494 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1495 HERMES, IP860, RPXlite, LWMON, LANTEC,
1496 PCU_E, FLAGADM, TQM8260
1501 Define this variable to stop the system in case of a
1502 fatal error, so that you have to reset it manually.
1503 This is probably NOT a good idea for an embedded
1504 system where you want to system to reboot
1505 automatically as fast as possible, but it may be
1506 useful during development since you can try to debug
1507 the conditions that lead to the situation.
1509 CONFIG_NET_RETRY_COUNT
1511 This variable defines the number of retries for
1512 network operations like ARP, RARP, TFTP, or BOOTP
1513 before giving up the operation. If not defined, a
1514 default value of 5 is used.
1516 - Command Interpreter:
1517 CONFIG_AUTO_COMPLETE
1519 Enable auto completion of commands using TAB.
1521 Note that this feature has NOT been implemented yet
1522 for the "hush" shell.
1527 Define this variable to enable the "hush" shell (from
1528 Busybox) as command line interpreter, thus enabling
1529 powerful command line syntax like
1530 if...then...else...fi conditionals or `&&' and '||'
1531 constructs ("shell scripts").
1533 If undefined, you get the old, much simpler behaviour
1534 with a somewhat smaller memory footprint.
1539 This defines the secondary prompt string, which is
1540 printed when the command interpreter needs more input
1541 to complete a command. Usually "> ".
1545 In the current implementation, the local variables
1546 space and global environment variables space are
1547 separated. Local variables are those you define by
1548 simply typing `name=value'. To access a local
1549 variable later on, you have write `$name' or
1550 `${name}'; to execute the contents of a variable
1551 directly type `$name' at the command prompt.
1553 Global environment variables are those you use
1554 setenv/printenv to work with. To run a command stored
1555 in such a variable, you need to use the run command,
1556 and you must not use the '$' sign to access them.
1558 To store commands and special characters in a
1559 variable, please use double quotation marks
1560 surrounding the whole text of the variable, instead
1561 of the backslashes before semicolons and special
1564 - Commandline Editing and History:
1565 CONFIG_CMDLINE_EDITING
1567 Enable editiong and History functions for interactive
1568 commandline input operations
1570 - Default Environment:
1571 CONFIG_EXTRA_ENV_SETTINGS
1573 Define this to contain any number of null terminated
1574 strings (variable = value pairs) that will be part of
1575 the default environment compiled into the boot image.
1577 For example, place something like this in your
1578 board's config file:
1580 #define CONFIG_EXTRA_ENV_SETTINGS \
1584 Warning: This method is based on knowledge about the
1585 internal format how the environment is stored by the
1586 U-Boot code. This is NOT an official, exported
1587 interface! Although it is unlikely that this format
1588 will change soon, there is no guarantee either.
1589 You better know what you are doing here.
1591 Note: overly (ab)use of the default environment is
1592 discouraged. Make sure to check other ways to preset
1593 the environment like the autoscript function or the
1596 - DataFlash Support:
1597 CONFIG_HAS_DATAFLASH
1599 Defining this option enables DataFlash features and
1600 allows to read/write in Dataflash via the standard
1603 - SystemACE Support:
1606 Adding this option adds support for Xilinx SystemACE
1607 chips attached via some sort of local bus. The address
1608 of the chip must alsh be defined in the
1609 CFG_SYSTEMACE_BASE macro. For example:
1611 #define CONFIG_SYSTEMACE
1612 #define CFG_SYSTEMACE_BASE 0xf0000000
1614 When SystemACE support is added, the "ace" device type
1615 becomes available to the fat commands, i.e. fatls.
1617 - TFTP Fixed UDP Port:
1620 If this is defined, the environment variable tftpsrcp
1621 is used to supply the TFTP UDP source port value.
1622 If tftpsrcp isn't defined, the normal pseudo-random port
1623 number generator is used.
1625 Also, the environment variable tftpdstp is used to supply
1626 the TFTP UDP destination port value. If tftpdstp isn't
1627 defined, the normal port 69 is used.
1629 The purpose for tftpsrcp is to allow a TFTP server to
1630 blindly start the TFTP transfer using the pre-configured
1631 target IP address and UDP port. This has the effect of
1632 "punching through" the (Windows XP) firewall, allowing
1633 the remainder of the TFTP transfer to proceed normally.
1634 A better solution is to properly configure the firewall,
1635 but sometimes that is not allowed.
1637 - Show boot progress:
1638 CONFIG_SHOW_BOOT_PROGRESS
1640 Defining this option allows to add some board-
1641 specific code (calling a user-provided function
1642 "show_boot_progress(int)") that enables you to show
1643 the system's boot progress on some display (for
1644 example, some LED's) on your board. At the moment,
1645 the following checkpoints are implemented:
1648 1 common/cmd_bootm.c before attempting to boot an image
1649 -1 common/cmd_bootm.c Image header has bad magic number
1650 2 common/cmd_bootm.c Image header has correct magic number
1651 -2 common/cmd_bootm.c Image header has bad checksum
1652 3 common/cmd_bootm.c Image header has correct checksum
1653 -3 common/cmd_bootm.c Image data has bad checksum
1654 4 common/cmd_bootm.c Image data has correct checksum
1655 -4 common/cmd_bootm.c Image is for unsupported architecture
1656 5 common/cmd_bootm.c Architecture check OK
1657 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1658 6 common/cmd_bootm.c Image Type check OK
1659 -6 common/cmd_bootm.c gunzip uncompression error
1660 -7 common/cmd_bootm.c Unimplemented compression type
1661 7 common/cmd_bootm.c Uncompression OK
1662 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1663 8 common/cmd_bootm.c Image Type check OK
1664 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1665 9 common/cmd_bootm.c Start initial ramdisk verification
1666 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1667 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1668 10 common/cmd_bootm.c Ramdisk header is OK
1669 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1670 11 common/cmd_bootm.c Ramdisk data has correct checksum
1671 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1672 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1673 13 common/cmd_bootm.c Start multifile image verification
1674 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1675 15 common/cmd_bootm.c All preparation done, transferring control to OS
1677 -30 lib_ppc/board.c Fatal error, hang the system
1678 -31 post/post.c POST test failed, detected by post_output_backlog()
1679 -32 post/post.c POST test failed, detected by post_run_single()
1681 34 common/cmd_doc.c before loading a Image from a DOC device
1682 -35 common/cmd_doc.c Bad usage of "doc" command
1683 35 common/cmd_doc.c correct usage of "doc" command
1684 -36 common/cmd_doc.c No boot device
1685 36 common/cmd_doc.c correct boot device
1686 -37 common/cmd_doc.c Unknown Chip ID on boot device
1687 37 common/cmd_doc.c correct chip ID found, device available
1688 -38 common/cmd_doc.c Read Error on boot device
1689 38 common/cmd_doc.c reading Image header from DOC device OK
1690 -39 common/cmd_doc.c Image header has bad magic number
1691 39 common/cmd_doc.c Image header has correct magic number
1692 -40 common/cmd_doc.c Error reading Image from DOC device
1693 40 common/cmd_doc.c Image header has correct magic number
1694 41 common/cmd_ide.c before loading a Image from a IDE device
1695 -42 common/cmd_ide.c Bad usage of "ide" command
1696 42 common/cmd_ide.c correct usage of "ide" command
1697 -43 common/cmd_ide.c No boot device
1698 43 common/cmd_ide.c boot device found
1699 -44 common/cmd_ide.c Device not available
1700 44 common/cmd_ide.c Device available
1701 -45 common/cmd_ide.c wrong partition selected
1702 45 common/cmd_ide.c partition selected
1703 -46 common/cmd_ide.c Unknown partition table
1704 46 common/cmd_ide.c valid partition table found
1705 -47 common/cmd_ide.c Invalid partition type
1706 47 common/cmd_ide.c correct partition type
1707 -48 common/cmd_ide.c Error reading Image Header on boot device
1708 48 common/cmd_ide.c reading Image Header from IDE device OK
1709 -49 common/cmd_ide.c Image header has bad magic number
1710 49 common/cmd_ide.c Image header has correct magic number
1711 -50 common/cmd_ide.c Image header has bad checksum
1712 50 common/cmd_ide.c Image header has correct checksum
1713 -51 common/cmd_ide.c Error reading Image from IDE device
1714 51 common/cmd_ide.c reading Image from IDE device OK
1715 52 common/cmd_nand.c before loading a Image from a NAND device
1716 -53 common/cmd_nand.c Bad usage of "nand" command
1717 53 common/cmd_nand.c correct usage of "nand" command
1718 -54 common/cmd_nand.c No boot device
1719 54 common/cmd_nand.c boot device found
1720 -55 common/cmd_nand.c Unknown Chip ID on boot device
1721 55 common/cmd_nand.c correct chip ID found, device available
1722 -56 common/cmd_nand.c Error reading Image Header on boot device
1723 56 common/cmd_nand.c reading Image Header from NAND device OK
1724 -57 common/cmd_nand.c Image header has bad magic number
1725 57 common/cmd_nand.c Image header has correct magic number
1726 -58 common/cmd_nand.c Error reading Image from NAND device
1727 58 common/cmd_nand.c reading Image from NAND device OK
1729 -60 common/env_common.c Environment has a bad CRC, using default
1731 64 net/eth.c starting with Ethernetconfiguration.
1732 -64 net/eth.c no Ethernet found.
1733 65 net/eth.c Ethernet found.
1735 -80 common/cmd_net.c usage wrong
1736 80 common/cmd_net.c before calling NetLoop()
1737 -81 common/cmd_net.c some error in NetLoop() occured
1738 81 common/cmd_net.c NetLoop() back without error
1739 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1740 82 common/cmd_net.c trying automatic boot
1741 83 common/cmd_net.c running autoscript
1742 -83 common/cmd_net.c some error in automatic boot or autoscript
1743 84 common/cmd_net.c end without errors
1748 [so far only for SMDK2400 and TRAB boards]
1750 - Modem support endable:
1751 CONFIG_MODEM_SUPPORT
1753 - RTS/CTS Flow control enable:
1756 - Modem debug support:
1757 CONFIG_MODEM_SUPPORT_DEBUG
1759 Enables debugging stuff (char screen[1024], dbg())
1760 for modem support. Useful only with BDI2000.
1762 - Interrupt support (PPC):
1764 There are common interrupt_init() and timer_interrupt()
1765 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1766 for cpu specific initialization. interrupt_init_cpu()
1767 should set decrementer_count to appropriate value. If
1768 cpu resets decrementer automatically after interrupt
1769 (ppc4xx) it should set decrementer_count to zero.
1770 timer_interrupt() calls timer_interrupt_cpu() for cpu
1771 specific handling. If board has watchdog / status_led
1772 / other_activity_monitor it works automatically from
1773 general timer_interrupt().
1777 In the target system modem support is enabled when a
1778 specific key (key combination) is pressed during
1779 power-on. Otherwise U-Boot will boot normally
1780 (autoboot). The key_pressed() fuction is called from
1781 board_init(). Currently key_pressed() is a dummy
1782 function, returning 1 and thus enabling modem
1785 If there are no modem init strings in the
1786 environment, U-Boot proceed to autoboot; the
1787 previous output (banner, info printfs) will be
1790 See also: doc/README.Modem
1793 Configuration Settings:
1794 -----------------------
1796 - CFG_LONGHELP: Defined when you want long help messages included;
1797 undefine this when you're short of memory.
1799 - CFG_PROMPT: This is what U-Boot prints on the console to
1800 prompt for user input.
1802 - CFG_CBSIZE: Buffer size for input from the Console
1804 - CFG_PBSIZE: Buffer size for Console output
1806 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1808 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1809 the application (usually a Linux kernel) when it is
1812 - CFG_BAUDRATE_TABLE:
1813 List of legal baudrate settings for this board.
1815 - CFG_CONSOLE_INFO_QUIET
1816 Suppress display of console information at boot.
1818 - CFG_CONSOLE_IS_IN_ENV
1819 If the board specific function
1820 extern int overwrite_console (void);
1821 returns 1, the stdin, stderr and stdout are switched to the
1822 serial port, else the settings in the environment are used.
1824 - CFG_CONSOLE_OVERWRITE_ROUTINE
1825 Enable the call to overwrite_console().
1827 - CFG_CONSOLE_ENV_OVERWRITE
1828 Enable overwrite of previous console environment settings.
1830 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1831 Begin and End addresses of the area used by the
1835 Enable an alternate, more extensive memory test.
1837 - CFG_MEMTEST_SCRATCH:
1838 Scratch address used by the alternate memory test
1839 You only need to set this if address zero isn't writeable
1841 - CFG_TFTP_LOADADDR:
1842 Default load address for network file downloads
1844 - CFG_LOADS_BAUD_CHANGE:
1845 Enable temporary baudrate change while serial download
1848 Physical start address of SDRAM. _Must_ be 0 here.
1851 Physical start address of Motherboard I/O (if using a
1855 Physical start address of Flash memory.
1858 Physical start address of boot monitor code (set by
1859 make config files to be same as the text base address
1860 (TEXT_BASE) used when linking) - same as
1861 CFG_FLASH_BASE when booting from flash.
1864 Size of memory reserved for monitor code, used to
1865 determine _at_compile_time_ (!) if the environment is
1866 embedded within the U-Boot image, or in a separate
1870 Size of DRAM reserved for malloc() use.
1873 Normally compressed uImages are limited to an
1874 uncompressed size of 8 MBytes. If this is not enough,
1875 you can define CFG_BOOTM_LEN in your board config file
1876 to adjust this setting to your needs.
1879 Maximum size of memory mapped by the startup code of
1880 the Linux kernel; all data that must be processed by
1881 the Linux kernel (bd_info, boot arguments, eventually
1882 initrd image) must be put below this limit.
1884 - CFG_MAX_FLASH_BANKS:
1885 Max number of Flash memory banks
1887 - CFG_MAX_FLASH_SECT:
1888 Max number of sectors on a Flash chip
1890 - CFG_FLASH_ERASE_TOUT:
1891 Timeout for Flash erase operations (in ms)
1893 - CFG_FLASH_WRITE_TOUT:
1894 Timeout for Flash write operations (in ms)
1896 - CFG_FLASH_LOCK_TOUT
1897 Timeout for Flash set sector lock bit operation (in ms)
1899 - CFG_FLASH_UNLOCK_TOUT
1900 Timeout for Flash clear lock bits operation (in ms)
1902 - CFG_FLASH_PROTECTION
1903 If defined, hardware flash sectors protection is used
1904 instead of U-Boot software protection.
1906 - CFG_DIRECT_FLASH_TFTP:
1908 Enable TFTP transfers directly to flash memory;
1909 without this option such a download has to be
1910 performed in two steps: (1) download to RAM, and (2)
1911 copy from RAM to flash.
1913 The two-step approach is usually more reliable, since
1914 you can check if the download worked before you erase
1915 the flash, but in some situations (when sytem RAM is
1916 too limited to allow for a tempory copy of the
1917 downloaded image) this option may be very useful.
1920 Define if the flash driver uses extra elements in the
1921 common flash structure for storing flash geometry.
1923 - CFG_FLASH_CFI_DRIVER
1924 This option also enables the building of the cfi_flash driver
1925 in the drivers directory
1927 - CFG_FLASH_QUIET_TEST
1928 If this option is defined, the common CFI flash doesn't
1929 print it's warning upon not recognized FLASH banks. This
1930 is useful, if some of the configured banks are only
1931 optionally available.
1933 - CFG_RX_ETH_BUFFER:
1934 Defines the number of ethernet receive buffers. On some
1935 ethernet controllers it is recommended to set this value
1936 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1937 buffers can be full shortly after enabling the interface
1938 on high ethernet traffic.
1939 Defaults to 4 if not defined.
1941 The following definitions that deal with the placement and management
1942 of environment data (variable area); in general, we support the
1943 following configurations:
1945 - CFG_ENV_IS_IN_FLASH:
1947 Define this if the environment is in flash memory.
1949 a) The environment occupies one whole flash sector, which is
1950 "embedded" in the text segment with the U-Boot code. This
1951 happens usually with "bottom boot sector" or "top boot
1952 sector" type flash chips, which have several smaller
1953 sectors at the start or the end. For instance, such a
1954 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1955 such a case you would place the environment in one of the
1956 4 kB sectors - with U-Boot code before and after it. With
1957 "top boot sector" type flash chips, you would put the
1958 environment in one of the last sectors, leaving a gap
1959 between U-Boot and the environment.
1963 Offset of environment data (variable area) to the
1964 beginning of flash memory; for instance, with bottom boot
1965 type flash chips the second sector can be used: the offset
1966 for this sector is given here.
1968 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1972 This is just another way to specify the start address of
1973 the flash sector containing the environment (instead of
1976 - CFG_ENV_SECT_SIZE:
1978 Size of the sector containing the environment.
1981 b) Sometimes flash chips have few, equal sized, BIG sectors.
1982 In such a case you don't want to spend a whole sector for
1987 If you use this in combination with CFG_ENV_IS_IN_FLASH
1988 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1989 of this flash sector for the environment. This saves
1990 memory for the RAM copy of the environment.
1992 It may also save flash memory if you decide to use this
1993 when your environment is "embedded" within U-Boot code,
1994 since then the remainder of the flash sector could be used
1995 for U-Boot code. It should be pointed out that this is
1996 STRONGLY DISCOURAGED from a robustness point of view:
1997 updating the environment in flash makes it always
1998 necessary to erase the WHOLE sector. If something goes
1999 wrong before the contents has been restored from a copy in
2000 RAM, your target system will be dead.
2002 - CFG_ENV_ADDR_REDUND
2005 These settings describe a second storage area used to hold
2006 a redundand copy of the environment data, so that there is
2007 a valid backup copy in case there is a power failure during
2008 a "saveenv" operation.
2010 BE CAREFUL! Any changes to the flash layout, and some changes to the
2011 source code will make it necessary to adapt <board>/u-boot.lds*
2015 - CFG_ENV_IS_IN_NVRAM:
2017 Define this if you have some non-volatile memory device
2018 (NVRAM, battery buffered SRAM) which you want to use for the
2024 These two #defines are used to determin the memory area you
2025 want to use for environment. It is assumed that this memory
2026 can just be read and written to, without any special
2029 BE CAREFUL! The first access to the environment happens quite early
2030 in U-Boot initalization (when we try to get the setting of for the
2031 console baudrate). You *MUST* have mappend your NVRAM area then, or
2034 Please note that even with NVRAM we still use a copy of the
2035 environment in RAM: we could work on NVRAM directly, but we want to
2036 keep settings there always unmodified except somebody uses "saveenv"
2037 to save the current settings.
2040 - CFG_ENV_IS_IN_EEPROM:
2042 Use this if you have an EEPROM or similar serial access
2043 device and a driver for it.
2048 These two #defines specify the offset and size of the
2049 environment area within the total memory of your EEPROM.
2051 - CFG_I2C_EEPROM_ADDR:
2052 If defined, specified the chip address of the EEPROM device.
2053 The default address is zero.
2055 - CFG_EEPROM_PAGE_WRITE_BITS:
2056 If defined, the number of bits used to address bytes in a
2057 single page in the EEPROM device. A 64 byte page, for example
2058 would require six bits.
2060 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2061 If defined, the number of milliseconds to delay between
2062 page writes. The default is zero milliseconds.
2064 - CFG_I2C_EEPROM_ADDR_LEN:
2065 The length in bytes of the EEPROM memory array address. Note
2066 that this is NOT the chip address length!
2068 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2069 EEPROM chips that implement "address overflow" are ones
2070 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2071 address and the extra bits end up in the "chip address" bit
2072 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2075 Note that we consider the length of the address field to
2076 still be one byte because the extra address bits are hidden
2077 in the chip address.
2080 The size in bytes of the EEPROM device.
2083 - CFG_ENV_IS_IN_DATAFLASH:
2085 Define this if you have a DataFlash memory device which you
2086 want to use for the environment.
2092 These three #defines specify the offset and size of the
2093 environment area within the total memory of your DataFlash placed
2094 at the specified address.
2096 - CFG_ENV_IS_IN_NAND:
2098 Define this if you have a NAND device which you want to use
2099 for the environment.
2104 These two #defines specify the offset and size of the environment
2105 area within the first NAND device.
2107 - CFG_ENV_OFFSET_REDUND
2109 This setting describes a second storage area of CFG_ENV_SIZE
2110 size used to hold a redundant copy of the environment data,
2111 so that there is a valid backup copy in case there is a
2112 power failure during a "saveenv" operation.
2114 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2115 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2116 the NAND devices block size.
2118 - CFG_SPI_INIT_OFFSET
2120 Defines offset to the initial SPI buffer area in DPRAM. The
2121 area is used at an early stage (ROM part) if the environment
2122 is configured to reside in the SPI EEPROM: We need a 520 byte
2123 scratch DPRAM area. It is used between the two initialization
2124 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2125 to be a good choice since it makes it far enough from the
2126 start of the data area as well as from the stack pointer.
2128 Please note that the environment is read-only as long as the monitor
2129 has been relocated to RAM and a RAM copy of the environment has been
2130 created; also, when using EEPROM you will have to use getenv_r()
2131 until then to read environment variables.
2133 The environment is protected by a CRC32 checksum. Before the monitor
2134 is relocated into RAM, as a result of a bad CRC you will be working
2135 with the compiled-in default environment - *silently*!!! [This is
2136 necessary, because the first environment variable we need is the
2137 "baudrate" setting for the console - if we have a bad CRC, we don't
2138 have any device yet where we could complain.]
2140 Note: once the monitor has been relocated, then it will complain if
2141 the default environment is used; a new CRC is computed as soon as you
2142 use the "saveenv" command to store a valid environment.
2144 - CFG_FAULT_ECHO_LINK_DOWN:
2145 Echo the inverted Ethernet link state to the fault LED.
2147 Note: If this option is active, then CFG_FAULT_MII_ADDR
2148 also needs to be defined.
2150 - CFG_FAULT_MII_ADDR:
2151 MII address of the PHY to check for the Ethernet link state.
2153 - CFG_64BIT_VSPRINTF:
2154 Makes vsprintf (and all *printf functions) support printing
2155 of 64bit values by using the L quantifier
2157 - CFG_64BIT_STRTOUL:
2158 Adds simple_strtoull that returns a 64bit value
2160 Low Level (hardware related) configuration options:
2161 ---------------------------------------------------
2163 - CFG_CACHELINE_SIZE:
2164 Cache Line Size of the CPU.
2167 Default address of the IMMR after system reset.
2169 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2170 and RPXsuper) to be able to adjust the position of
2171 the IMMR register after a reset.
2173 - Floppy Disk Support:
2174 CFG_FDC_DRIVE_NUMBER
2176 the default drive number (default value 0)
2180 defines the spacing between fdc chipset registers
2185 defines the offset of register from address. It
2186 depends on which part of the data bus is connected to
2187 the fdc chipset. (default value 0)
2189 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2190 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2193 if CFG_FDC_HW_INIT is defined, then the function
2194 fdc_hw_init() is called at the beginning of the FDC
2195 setup. fdc_hw_init() must be provided by the board
2196 source code. It is used to make hardware dependant
2199 - CFG_IMMR: Physical address of the Internal Memory.
2200 DO NOT CHANGE unless you know exactly what you're
2201 doing! (11-4) [MPC8xx/82xx systems only]
2203 - CFG_INIT_RAM_ADDR:
2205 Start address of memory area that can be used for
2206 initial data and stack; please note that this must be
2207 writable memory that is working WITHOUT special
2208 initialization, i. e. you CANNOT use normal RAM which
2209 will become available only after programming the
2210 memory controller and running certain initialization
2213 U-Boot uses the following memory types:
2214 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2215 - MPC824X: data cache
2216 - PPC4xx: data cache
2218 - CFG_GBL_DATA_OFFSET:
2220 Offset of the initial data structure in the memory
2221 area defined by CFG_INIT_RAM_ADDR. Usually
2222 CFG_GBL_DATA_OFFSET is chosen such that the initial
2223 data is located at the end of the available space
2224 (sometimes written as (CFG_INIT_RAM_END -
2225 CFG_INIT_DATA_SIZE), and the initial stack is just
2226 below that area (growing from (CFG_INIT_RAM_ADDR +
2227 CFG_GBL_DATA_OFFSET) downward.
2230 On the MPC824X (or other systems that use the data
2231 cache for initial memory) the address chosen for
2232 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2233 point to an otherwise UNUSED address space between
2234 the top of RAM and the start of the PCI space.
2236 - CFG_SIUMCR: SIU Module Configuration (11-6)
2238 - CFG_SYPCR: System Protection Control (11-9)
2240 - CFG_TBSCR: Time Base Status and Control (11-26)
2242 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2244 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2246 - CFG_SCCR: System Clock and reset Control Register (15-27)
2248 - CFG_OR_TIMING_SDRAM:
2252 periodic timer for refresh
2254 - CFG_DER: Debug Event Register (37-47)
2256 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2257 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2258 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2260 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2262 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2263 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2264 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2265 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2267 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2268 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2269 Machine Mode Register and Memory Periodic Timer
2270 Prescaler definitions (SDRAM timing)
2272 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2273 enable I2C microcode relocation patch (MPC8xx);
2274 define relocation offset in DPRAM [DSP2]
2276 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2277 enable SPI microcode relocation patch (MPC8xx);
2278 define relocation offset in DPRAM [SCC4]
2281 Use OSCM clock mode on MBX8xx board. Be careful,
2282 wrong setting might damage your board. Read
2283 doc/README.MBX before setting this variable!
2285 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2286 Offset of the bootmode word in DPRAM used by post
2287 (Power On Self Tests). This definition overrides
2288 #define'd default value in commproc.h resp.
2291 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2292 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2293 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2294 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2295 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2296 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2297 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2298 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2299 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2302 Get DDR timing information from an I2C EEPROM. Common with pluggable
2303 memory modules such as SODIMMs
2305 I2C address of the SPD EEPROM
2308 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2309 Note that the value must resolve to something your driver can deal with.
2311 - CFG_83XX_DDR_USES_CS0
2312 Only for 83xx systems. If specified, then DDR should be configured
2313 using CS0 and CS1 instead of CS2 and CS3.
2315 - CFG_83XX_DDR_USES_CS0
2316 Only for 83xx systems. If specified, then DDR should be configured
2317 using CS0 and CS1 instead of CS2 and CS3.
2319 - CONFIG_ETHER_ON_FEC[12]
2320 Define to enable FEC[12] on a 8xx series processor.
2322 - CONFIG_FEC[12]_PHY
2323 Define to the hardcoded PHY address which corresponds
2324 to the given FEC; i. e.
2325 #define CONFIG_FEC1_PHY 4
2326 means that the PHY with address 4 is connected to FEC1
2328 When set to -1, means to probe for first available.
2330 - CONFIG_FEC[12]_PHY_NORXERR
2331 The PHY does not have a RXERR line (RMII only).
2332 (so program the FEC to ignore it).
2335 Enable RMII mode for all FECs.
2336 Note that this is a global option, we can't
2337 have one FEC in standard MII mode and another in RMII mode.
2339 - CONFIG_CRC32_VERIFY
2340 Add a verify option to the crc32 command.
2343 => crc32 -v <address> <count> <crc32>
2345 Where address/count indicate a memory area
2346 and crc32 is the correct crc32 which the
2350 Add the "loopw" memory command. This only takes effect if
2351 the memory commands are activated globally (CONFIG_CMD_MEM).
2354 Add the "mdc" and "mwc" memory commands. These are cyclic
2359 This command will print 4 bytes (10,11,12,13) each 500 ms.
2361 => mwc.l 100 12345678 10
2362 This command will write 12345678 to address 100 all 10 ms.
2364 This only takes effect if the memory commands are activated
2365 globally (CONFIG_CMD_MEM).
2367 - CONFIG_SKIP_LOWLEVEL_INIT
2368 - CONFIG_SKIP_RELOCATE_UBOOT
2370 [ARM only] If these variables are defined, then
2371 certain low level initializations (like setting up
2372 the memory controller) are omitted and/or U-Boot does
2373 not relocate itself into RAM.
2374 Normally these variables MUST NOT be defined. The
2375 only exception is when U-Boot is loaded (to RAM) by
2376 some other boot loader or by a debugger which
2377 performs these intializations itself.
2380 Building the Software:
2381 ======================
2383 Building U-Boot has been tested in native PPC environments (on a
2384 PowerBook G3 running LinuxPPC 2000) and in cross environments
2385 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2388 If you are not using a native PPC environment, it is assumed that you
2389 have the GNU cross compiling tools available in your path and named
2390 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2391 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2392 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2395 CROSS_COMPILE = ppc_4xx-
2398 U-Boot is intended to be simple to build. After installing the
2399 sources you must configure U-Boot for one specific board type. This
2404 where "NAME_config" is the name of one of the existing
2405 configurations; see the main Makefile for supported names.
2407 Note: for some board special configuration names may exist; check if
2408 additional information is available from the board vendor; for
2409 instance, the TQM823L systems are available without (standard)
2410 or with LCD support. You can select such additional "features"
2411 when chosing the configuration, i. e.
2414 - will configure for a plain TQM823L, i. e. no LCD support
2416 make TQM823L_LCD_config
2417 - will configure for a TQM823L with U-Boot console on LCD
2422 Finally, type "make all", and you should get some working U-Boot
2423 images ready for download to / installation on your system:
2425 - "u-boot.bin" is a raw binary image
2426 - "u-boot" is an image in ELF binary format
2427 - "u-boot.srec" is in Motorola S-Record format
2429 By default the build is performed locally and the objects are saved
2430 in the source directory. One of the two methods can be used to change
2431 this behavior and build U-Boot to some external directory:
2433 1. Add O= to the make command line invocations:
2435 make O=/tmp/build distclean
2436 make O=/tmp/build NAME_config
2437 make O=/tmp/build all
2439 2. Set environment variable BUILD_DIR to point to the desired location:
2441 export BUILD_DIR=/tmp/build
2446 Note that the command line "O=" setting overrides the BUILD_DIR environment
2450 Please be aware that the Makefiles assume you are using GNU make, so
2451 for instance on NetBSD you might need to use "gmake" instead of
2455 If the system board that you have is not listed, then you will need
2456 to port U-Boot to your hardware platform. To do this, follow these
2459 1. Add a new configuration option for your board to the toplevel
2460 "Makefile" and to the "MAKEALL" script, using the existing
2461 entries as examples. Note that here and at many other places
2462 boards and other names are listed in alphabetical sort order. Please
2464 2. Create a new directory to hold your board specific code. Add any
2465 files you need. In your board directory, you will need at least
2466 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2467 3. Create a new configuration file "include/configs/<board>.h" for
2469 3. If you're porting U-Boot to a new CPU, then also create a new
2470 directory to hold your CPU specific code. Add any files you need.
2471 4. Run "make <board>_config" with your new name.
2472 5. Type "make", and you should get a working "u-boot.srec" file
2473 to be installed on your target system.
2474 6. Debug and solve any problems that might arise.
2475 [Of course, this last step is much harder than it sounds.]
2478 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2479 ==============================================================
2481 If you have modified U-Boot sources (for instance added a new board
2482 or support for new devices, a new CPU, etc.) you are expected to
2483 provide feedback to the other developers. The feedback normally takes
2484 the form of a "patch", i. e. a context diff against a certain (latest
2485 official or latest in CVS) version of U-Boot sources.
2487 But before you submit such a patch, please verify that your modifi-
2488 cation did not break existing code. At least make sure that *ALL* of
2489 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2490 just run the "MAKEALL" script, which will configure and build U-Boot
2491 for ALL supported system. Be warned, this will take a while. You can
2492 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2493 environment variable to the script, i. e. to use the cross tools from
2494 MontaVista's Hard Hat Linux you can type
2496 CROSS_COMPILE=ppc_8xx- MAKEALL
2498 or to build on a native PowerPC system you can type
2500 CROSS_COMPILE=' ' MAKEALL
2502 When using the MAKEALL script, the default behaviour is to build U-Boot
2503 in the source directory. This location can be changed by setting the
2504 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2505 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2506 <source dir>/LOG directory. This default location can be changed by
2507 setting the MAKEALL_LOGDIR environment variable. For example:
2509 export BUILD_DIR=/tmp/build
2510 export MAKEALL_LOGDIR=/tmp/log
2511 CROSS_COMPILE=ppc_8xx- MAKEALL
2513 With the above settings build objects are saved in the /tmp/build, log
2514 files are saved in the /tmp/log and the source tree remains clean during
2515 the whole build process.
2518 See also "U-Boot Porting Guide" below.
2521 Monitor Commands - Overview:
2522 ============================
2524 go - start application at address 'addr'
2525 run - run commands in an environment variable
2526 bootm - boot application image from memory
2527 bootp - boot image via network using BootP/TFTP protocol
2528 tftpboot- boot image via network using TFTP protocol
2529 and env variables "ipaddr" and "serverip"
2530 (and eventually "gatewayip")
2531 rarpboot- boot image via network using RARP/TFTP protocol
2532 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2533 loads - load S-Record file over serial line
2534 loadb - load binary file over serial line (kermit mode)
2536 mm - memory modify (auto-incrementing)
2537 nm - memory modify (constant address)
2538 mw - memory write (fill)
2540 cmp - memory compare
2541 crc32 - checksum calculation
2542 imd - i2c memory display
2543 imm - i2c memory modify (auto-incrementing)
2544 inm - i2c memory modify (constant address)
2545 imw - i2c memory write (fill)
2546 icrc32 - i2c checksum calculation
2547 iprobe - probe to discover valid I2C chip addresses
2548 iloop - infinite loop on address range
2549 isdram - print SDRAM configuration information
2550 sspi - SPI utility commands
2551 base - print or set address offset
2552 printenv- print environment variables
2553 setenv - set environment variables
2554 saveenv - save environment variables to persistent storage
2555 protect - enable or disable FLASH write protection
2556 erase - erase FLASH memory
2557 flinfo - print FLASH memory information
2558 bdinfo - print Board Info structure
2559 iminfo - print header information for application image
2560 coninfo - print console devices and informations
2561 ide - IDE sub-system
2562 loop - infinite loop on address range
2563 loopw - infinite write loop on address range
2564 mtest - simple RAM test
2565 icache - enable or disable instruction cache
2566 dcache - enable or disable data cache
2567 reset - Perform RESET of the CPU
2568 echo - echo args to console
2569 version - print monitor version
2570 help - print online help
2571 ? - alias for 'help'
2574 Monitor Commands - Detailed Description:
2575 ========================================
2579 For now: just type "help <command>".
2582 Environment Variables:
2583 ======================
2585 U-Boot supports user configuration using Environment Variables which
2586 can be made persistent by saving to Flash memory.
2588 Environment Variables are set using "setenv", printed using
2589 "printenv", and saved to Flash using "saveenv". Using "setenv"
2590 without a value can be used to delete a variable from the
2591 environment. As long as you don't save the environment you are
2592 working with an in-memory copy. In case the Flash area containing the
2593 environment is erased by accident, a default environment is provided.
2595 Some configuration options can be set using Environment Variables:
2597 baudrate - see CONFIG_BAUDRATE
2599 bootdelay - see CONFIG_BOOTDELAY
2601 bootcmd - see CONFIG_BOOTCOMMAND
2603 bootargs - Boot arguments when booting an RTOS image
2605 bootfile - Name of the image to load with TFTP
2607 autoload - if set to "no" (any string beginning with 'n'),
2608 "bootp" will just load perform a lookup of the
2609 configuration from the BOOTP server, but not try to
2610 load any image using TFTP
2612 autostart - if set to "yes", an image loaded using the "bootp",
2613 "rarpboot", "tftpboot" or "diskboot" commands will
2614 be automatically started (by internally calling
2617 If set to "no", a standalone image passed to the
2618 "bootm" command will be copied to the load address
2619 (and eventually uncompressed), but NOT be started.
2620 This can be used to load and uncompress arbitrary
2623 i2cfast - (PPC405GP|PPC405EP only)
2624 if set to 'y' configures Linux I2C driver for fast
2625 mode (400kHZ). This environment variable is used in
2626 initialization code. So, for changes to be effective
2627 it must be saved and board must be reset.
2629 initrd_high - restrict positioning of initrd images:
2630 If this variable is not set, initrd images will be
2631 copied to the highest possible address in RAM; this
2632 is usually what you want since it allows for
2633 maximum initrd size. If for some reason you want to
2634 make sure that the initrd image is loaded below the
2635 CFG_BOOTMAPSZ limit, you can set this environment
2636 variable to a value of "no" or "off" or "0".
2637 Alternatively, you can set it to a maximum upper
2638 address to use (U-Boot will still check that it
2639 does not overwrite the U-Boot stack and data).
2641 For instance, when you have a system with 16 MB
2642 RAM, and want to reserve 4 MB from use by Linux,
2643 you can do this by adding "mem=12M" to the value of
2644 the "bootargs" variable. However, now you must make
2645 sure that the initrd image is placed in the first
2646 12 MB as well - this can be done with
2648 setenv initrd_high 00c00000
2650 If you set initrd_high to 0xFFFFFFFF, this is an
2651 indication to U-Boot that all addresses are legal
2652 for the Linux kernel, including addresses in flash
2653 memory. In this case U-Boot will NOT COPY the
2654 ramdisk at all. This may be useful to reduce the
2655 boot time on your system, but requires that this
2656 feature is supported by your Linux kernel.
2658 ipaddr - IP address; needed for tftpboot command
2660 loadaddr - Default load address for commands like "bootp",
2661 "rarpboot", "tftpboot", "loadb" or "diskboot"
2663 loads_echo - see CONFIG_LOADS_ECHO
2665 serverip - TFTP server IP address; needed for tftpboot command
2667 bootretry - see CONFIG_BOOT_RETRY_TIME
2669 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2671 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2673 ethprime - When CONFIG_NET_MULTI is enabled controls which
2674 interface is used first.
2676 ethact - When CONFIG_NET_MULTI is enabled controls which
2677 interface is currently active. For example you
2678 can do the following
2680 => setenv ethact FEC ETHERNET
2681 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2682 => setenv ethact SCC ETHERNET
2683 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2685 netretry - When set to "no" each network operation will
2686 either succeed or fail without retrying.
2687 When set to "once" the network operation will
2688 fail when all the available network interfaces
2689 are tried once without success.
2690 Useful on scripts which control the retry operation
2693 tftpsrcport - If this is set, the value is used for TFTP's
2696 tftpdstport - If this is set, the value is used for TFTP's UDP
2697 destination port instead of the Well Know Port 69.
2699 vlan - When set to a value < 4095 the traffic over
2700 ethernet is encapsulated/received over 802.1q
2703 The following environment variables may be used and automatically
2704 updated by the network boot commands ("bootp" and "rarpboot"),
2705 depending the information provided by your boot server:
2707 bootfile - see above
2708 dnsip - IP address of your Domain Name Server
2709 dnsip2 - IP address of your secondary Domain Name Server
2710 gatewayip - IP address of the Gateway (Router) to use
2711 hostname - Target hostname
2713 netmask - Subnet Mask
2714 rootpath - Pathname of the root filesystem on the NFS server
2715 serverip - see above
2718 There are two special Environment Variables:
2720 serial# - contains hardware identification information such
2721 as type string and/or serial number
2722 ethaddr - Ethernet address
2724 These variables can be set only once (usually during manufacturing of
2725 the board). U-Boot refuses to delete or overwrite these variables
2726 once they have been set once.
2729 Further special Environment Variables:
2731 ver - Contains the U-Boot version string as printed
2732 with the "version" command. This variable is
2733 readonly (see CONFIG_VERSION_VARIABLE).
2736 Please note that changes to some configuration parameters may take
2737 only effect after the next boot (yes, that's just like Windoze :-).
2740 Command Line Parsing:
2741 =====================
2743 There are two different command line parsers available with U-Boot:
2744 the old "simple" one, and the much more powerful "hush" shell:
2746 Old, simple command line parser:
2747 --------------------------------
2749 - supports environment variables (through setenv / saveenv commands)
2750 - several commands on one line, separated by ';'
2751 - variable substitution using "... ${name} ..." syntax
2752 - special characters ('$', ';') can be escaped by prefixing with '\',
2754 setenv bootcmd bootm \${address}
2755 - You can also escape text by enclosing in single apostrophes, for example:
2756 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2761 - similar to Bourne shell, with control structures like
2762 if...then...else...fi, for...do...done; while...do...done,
2763 until...do...done, ...
2764 - supports environment ("global") variables (through setenv / saveenv
2765 commands) and local shell variables (through standard shell syntax
2766 "name=value"); only environment variables can be used with "run"
2772 (1) If a command line (or an environment variable executed by a "run"
2773 command) contains several commands separated by semicolon, and
2774 one of these commands fails, then the remaining commands will be
2777 (2) If you execute several variables with one call to run (i. e.
2778 calling run with a list af variables as arguments), any failing
2779 command will cause "run" to terminate, i. e. the remaining
2780 variables are not executed.
2782 Note for Redundant Ethernet Interfaces:
2783 =======================================
2785 Some boards come with redundant ethernet interfaces; U-Boot supports
2786 such configurations and is capable of automatic selection of a
2787 "working" interface when needed. MAC assignment works as follows:
2789 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2790 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2791 "eth1addr" (=>eth1), "eth2addr", ...
2793 If the network interface stores some valid MAC address (for instance
2794 in SROM), this is used as default address if there is NO correspon-
2795 ding setting in the environment; if the corresponding environment
2796 variable is set, this overrides the settings in the card; that means:
2798 o If the SROM has a valid MAC address, and there is no address in the
2799 environment, the SROM's address is used.
2801 o If there is no valid address in the SROM, and a definition in the
2802 environment exists, then the value from the environment variable is
2805 o If both the SROM and the environment contain a MAC address, and
2806 both addresses are the same, this MAC address is used.
2808 o If both the SROM and the environment contain a MAC address, and the
2809 addresses differ, the value from the environment is used and a
2812 o If neither SROM nor the environment contain a MAC address, an error
2819 The "boot" commands of this monitor operate on "image" files which
2820 can be basicly anything, preceeded by a special header; see the
2821 definitions in include/image.h for details; basicly, the header
2822 defines the following image properties:
2824 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2825 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2826 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2827 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2828 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2829 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2830 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2831 * Compression Type (uncompressed, gzip, bzip2)
2837 The header is marked by a special Magic Number, and both the header
2838 and the data portions of the image are secured against corruption by
2845 Although U-Boot should support any OS or standalone application
2846 easily, the main focus has always been on Linux during the design of
2849 U-Boot includes many features that so far have been part of some
2850 special "boot loader" code within the Linux kernel. Also, any
2851 "initrd" images to be used are no longer part of one big Linux image;
2852 instead, kernel and "initrd" are separate images. This implementation
2853 serves several purposes:
2855 - the same features can be used for other OS or standalone
2856 applications (for instance: using compressed images to reduce the
2857 Flash memory footprint)
2859 - it becomes much easier to port new Linux kernel versions because
2860 lots of low-level, hardware dependent stuff are done by U-Boot
2862 - the same Linux kernel image can now be used with different "initrd"
2863 images; of course this also means that different kernel images can
2864 be run with the same "initrd". This makes testing easier (you don't
2865 have to build a new "zImage.initrd" Linux image when you just
2866 change a file in your "initrd"). Also, a field-upgrade of the
2867 software is easier now.
2873 Porting Linux to U-Boot based systems:
2874 ---------------------------------------
2876 U-Boot cannot save you from doing all the necessary modifications to
2877 configure the Linux device drivers for use with your target hardware
2878 (no, we don't intend to provide a full virtual machine interface to
2881 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2883 Just make sure your machine specific header file (for instance
2884 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2885 Information structure as we define in include/u-boot.h, and make
2886 sure that your definition of IMAP_ADDR uses the same value as your
2887 U-Boot configuration in CFG_IMMR.
2890 Configuring the Linux kernel:
2891 -----------------------------
2893 No specific requirements for U-Boot. Make sure you have some root
2894 device (initial ramdisk, NFS) for your target system.
2897 Building a Linux Image:
2898 -----------------------
2900 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2901 not used. If you use recent kernel source, a new build target
2902 "uImage" will exist which automatically builds an image usable by
2903 U-Boot. Most older kernels also have support for a "pImage" target,
2904 which was introduced for our predecessor project PPCBoot and uses a
2905 100% compatible format.
2914 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2915 encapsulate a compressed Linux kernel image with header information,
2916 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2918 * build a standard "vmlinux" kernel image (in ELF binary format):
2920 * convert the kernel into a raw binary image:
2922 ${CROSS_COMPILE}-objcopy -O binary \
2923 -R .note -R .comment \
2924 -S vmlinux linux.bin
2926 * compress the binary image:
2930 * package compressed binary image for U-Boot:
2932 mkimage -A ppc -O linux -T kernel -C gzip \
2933 -a 0 -e 0 -n "Linux Kernel Image" \
2934 -d linux.bin.gz uImage
2937 The "mkimage" tool can also be used to create ramdisk images for use
2938 with U-Boot, either separated from the Linux kernel image, or
2939 combined into one file. "mkimage" encapsulates the images with a 64
2940 byte header containing information about target architecture,
2941 operating system, image type, compression method, entry points, time
2942 stamp, CRC32 checksums, etc.
2944 "mkimage" can be called in two ways: to verify existing images and
2945 print the header information, or to build new images.
2947 In the first form (with "-l" option) mkimage lists the information
2948 contained in the header of an existing U-Boot image; this includes
2949 checksum verification:
2951 tools/mkimage -l image
2952 -l ==> list image header information
2954 The second form (with "-d" option) is used to build a U-Boot image
2955 from a "data file" which is used as image payload:
2957 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2958 -n name -d data_file image
2959 -A ==> set architecture to 'arch'
2960 -O ==> set operating system to 'os'
2961 -T ==> set image type to 'type'
2962 -C ==> set compression type 'comp'
2963 -a ==> set load address to 'addr' (hex)
2964 -e ==> set entry point to 'ep' (hex)
2965 -n ==> set image name to 'name'
2966 -d ==> use image data from 'datafile'
2968 Right now, all Linux kernels for PowerPC systems use the same load
2969 address (0x00000000), but the entry point address depends on the
2972 - 2.2.x kernels have the entry point at 0x0000000C,
2973 - 2.3.x and later kernels have the entry point at 0x00000000.
2975 So a typical call to build a U-Boot image would read:
2977 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2978 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2979 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2980 > examples/uImage.TQM850L
2981 Image Name: 2.4.4 kernel for TQM850L
2982 Created: Wed Jul 19 02:34:59 2000
2983 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2984 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2985 Load Address: 0x00000000
2986 Entry Point: 0x00000000
2988 To verify the contents of the image (or check for corruption):
2990 -> tools/mkimage -l examples/uImage.TQM850L
2991 Image Name: 2.4.4 kernel for TQM850L
2992 Created: Wed Jul 19 02:34:59 2000
2993 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2994 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2995 Load Address: 0x00000000
2996 Entry Point: 0x00000000
2998 NOTE: for embedded systems where boot time is critical you can trade
2999 speed for memory and install an UNCOMPRESSED image instead: this
3000 needs more space in Flash, but boots much faster since it does not
3001 need to be uncompressed:
3003 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3004 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3005 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3006 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3007 > examples/uImage.TQM850L-uncompressed
3008 Image Name: 2.4.4 kernel for TQM850L
3009 Created: Wed Jul 19 02:34:59 2000
3010 Image Type: PowerPC Linux Kernel Image (uncompressed)
3011 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3012 Load Address: 0x00000000
3013 Entry Point: 0x00000000
3016 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3017 when your kernel is intended to use an initial ramdisk:
3019 -> tools/mkimage -n 'Simple Ramdisk Image' \
3020 > -A ppc -O linux -T ramdisk -C gzip \
3021 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3022 Image Name: Simple Ramdisk Image
3023 Created: Wed Jan 12 14:01:50 2000
3024 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3025 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3026 Load Address: 0x00000000
3027 Entry Point: 0x00000000
3030 Installing a Linux Image:
3031 -------------------------
3033 To downloading a U-Boot image over the serial (console) interface,
3034 you must convert the image to S-Record format:
3036 objcopy -I binary -O srec examples/image examples/image.srec
3038 The 'objcopy' does not understand the information in the U-Boot
3039 image header, so the resulting S-Record file will be relative to
3040 address 0x00000000. To load it to a given address, you need to
3041 specify the target address as 'offset' parameter with the 'loads'
3044 Example: install the image to address 0x40100000 (which on the
3045 TQM8xxL is in the first Flash bank):
3047 => erase 40100000 401FFFFF
3053 ## Ready for S-Record download ...
3054 ~>examples/image.srec
3055 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3057 15989 15990 15991 15992
3058 [file transfer complete]
3060 ## Start Addr = 0x00000000
3063 You can check the success of the download using the 'iminfo' command;
3064 this includes a checksum verification so you can be sure no data
3065 corruption happened:
3069 ## Checking Image at 40100000 ...
3070 Image Name: 2.2.13 for initrd on TQM850L
3071 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3072 Data Size: 335725 Bytes = 327 kB = 0 MB
3073 Load Address: 00000000
3074 Entry Point: 0000000c
3075 Verifying Checksum ... OK
3081 The "bootm" command is used to boot an application that is stored in
3082 memory (RAM or Flash). In case of a Linux kernel image, the contents
3083 of the "bootargs" environment variable is passed to the kernel as
3084 parameters. You can check and modify this variable using the
3085 "printenv" and "setenv" commands:
3088 => printenv bootargs
3089 bootargs=root=/dev/ram
3091 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3093 => printenv bootargs
3094 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3097 ## Booting Linux kernel at 40020000 ...
3098 Image Name: 2.2.13 for NFS on TQM850L
3099 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3100 Data Size: 381681 Bytes = 372 kB = 0 MB
3101 Load Address: 00000000
3102 Entry Point: 0000000c
3103 Verifying Checksum ... OK
3104 Uncompressing Kernel Image ... OK
3105 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
3106 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3107 time_init: decrementer frequency = 187500000/60
3108 Calibrating delay loop... 49.77 BogoMIPS
3109 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3112 If you want to boot a Linux kernel with initial ram disk, you pass
3113 the memory addresses of both the kernel and the initrd image (PPBCOOT
3114 format!) to the "bootm" command:
3116 => imi 40100000 40200000
3118 ## Checking Image at 40100000 ...
3119 Image Name: 2.2.13 for initrd on TQM850L
3120 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3121 Data Size: 335725 Bytes = 327 kB = 0 MB
3122 Load Address: 00000000
3123 Entry Point: 0000000c
3124 Verifying Checksum ... OK
3126 ## Checking Image at 40200000 ...
3127 Image Name: Simple Ramdisk Image
3128 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3129 Data Size: 566530 Bytes = 553 kB = 0 MB
3130 Load Address: 00000000
3131 Entry Point: 00000000
3132 Verifying Checksum ... OK
3134 => bootm 40100000 40200000
3135 ## Booting Linux kernel at 40100000 ...
3136 Image Name: 2.2.13 for initrd on TQM850L
3137 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3138 Data Size: 335725 Bytes = 327 kB = 0 MB
3139 Load Address: 00000000
3140 Entry Point: 0000000c
3141 Verifying Checksum ... OK
3142 Uncompressing Kernel Image ... OK
3143 ## Loading RAMDisk Image at 40200000 ...
3144 Image Name: Simple Ramdisk Image
3145 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3146 Data Size: 566530 Bytes = 553 kB = 0 MB
3147 Load Address: 00000000
3148 Entry Point: 00000000
3149 Verifying Checksum ... OK
3150 Loading Ramdisk ... OK
3151 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
3152 Boot arguments: root=/dev/ram
3153 time_init: decrementer frequency = 187500000/60
3154 Calibrating delay loop... 49.77 BogoMIPS
3156 RAMDISK: Compressed image found at block 0
3157 VFS: Mounted root (ext2 filesystem).
3161 Boot Linux and pass a flat device tree:
3164 First, U-Boot must be compiled with the appropriate defines. See the section
3165 titled "Linux Kernel Interface" above for a more in depth explanation. The
3166 following is an example of how to start a kernel and pass an updated
3172 oft=oftrees/mpc8540ads.dtb
3173 => tftp $oftaddr $oft
3174 Speed: 1000, full duplex
3176 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3177 Filename 'oftrees/mpc8540ads.dtb'.
3178 Load address: 0x300000
3181 Bytes transferred = 4106 (100a hex)
3182 => tftp $loadaddr $bootfile
3183 Speed: 1000, full duplex
3185 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3187 Load address: 0x200000
3188 Loading:############
3190 Bytes transferred = 1029407 (fb51f hex)
3195 => bootm $loadaddr - $oftaddr
3196 ## Booting image at 00200000 ...
3197 Image Name: Linux-2.6.17-dirty
3198 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3199 Data Size: 1029343 Bytes = 1005.2 kB
3200 Load Address: 00000000
3201 Entry Point: 00000000
3202 Verifying Checksum ... OK
3203 Uncompressing Kernel Image ... OK
3204 Booting using flat device tree at 0x300000
3205 Using MPC85xx ADS machine description
3206 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3210 More About U-Boot Image Types:
3211 ------------------------------
3213 U-Boot supports the following image types:
3215 "Standalone Programs" are directly runnable in the environment
3216 provided by U-Boot; it is expected that (if they behave
3217 well) you can continue to work in U-Boot after return from
3218 the Standalone Program.
3219 "OS Kernel Images" are usually images of some Embedded OS which
3220 will take over control completely. Usually these programs
3221 will install their own set of exception handlers, device
3222 drivers, set up the MMU, etc. - this means, that you cannot
3223 expect to re-enter U-Boot except by resetting the CPU.
3224 "RAMDisk Images" are more or less just data blocks, and their
3225 parameters (address, size) are passed to an OS kernel that is
3227 "Multi-File Images" contain several images, typically an OS
3228 (Linux) kernel image and one or more data images like
3229 RAMDisks. This construct is useful for instance when you want
3230 to boot over the network using BOOTP etc., where the boot
3231 server provides just a single image file, but you want to get
3232 for instance an OS kernel and a RAMDisk image.
3234 "Multi-File Images" start with a list of image sizes, each
3235 image size (in bytes) specified by an "uint32_t" in network
3236 byte order. This list is terminated by an "(uint32_t)0".
3237 Immediately after the terminating 0 follow the images, one by
3238 one, all aligned on "uint32_t" boundaries (size rounded up to
3239 a multiple of 4 bytes).
3241 "Firmware Images" are binary images containing firmware (like
3242 U-Boot or FPGA images) which usually will be programmed to
3245 "Script files" are command sequences that will be executed by
3246 U-Boot's command interpreter; this feature is especially
3247 useful when you configure U-Boot to use a real shell (hush)
3248 as command interpreter.
3254 One of the features of U-Boot is that you can dynamically load and
3255 run "standalone" applications, which can use some resources of
3256 U-Boot like console I/O functions or interrupt services.
3258 Two simple examples are included with the sources:
3263 'examples/hello_world.c' contains a small "Hello World" Demo
3264 application; it is automatically compiled when you build U-Boot.
3265 It's configured to run at address 0x00040004, so you can play with it
3269 ## Ready for S-Record download ...
3270 ~>examples/hello_world.srec
3271 1 2 3 4 5 6 7 8 9 10 11 ...
3272 [file transfer complete]
3274 ## Start Addr = 0x00040004
3276 => go 40004 Hello World! This is a test.
3277 ## Starting application at 0x00040004 ...
3288 Hit any key to exit ...
3290 ## Application terminated, rc = 0x0
3292 Another example, which demonstrates how to register a CPM interrupt
3293 handler with the U-Boot code, can be found in 'examples/timer.c'.
3294 Here, a CPM timer is set up to generate an interrupt every second.
3295 The interrupt service routine is trivial, just printing a '.'
3296 character, but this is just a demo program. The application can be
3297 controlled by the following keys:
3299 ? - print current values og the CPM Timer registers
3300 b - enable interrupts and start timer
3301 e - stop timer and disable interrupts
3302 q - quit application
3305 ## Ready for S-Record download ...
3306 ~>examples/timer.srec
3307 1 2 3 4 5 6 7 8 9 10 11 ...
3308 [file transfer complete]
3310 ## Start Addr = 0x00040004
3313 ## Starting application at 0x00040004 ...
3316 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3319 [q, b, e, ?] Set interval 1000000 us
3322 [q, b, e, ?] ........
3323 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3326 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3329 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3332 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3334 [q, b, e, ?] ...Stopping timer
3336 [q, b, e, ?] ## Application terminated, rc = 0x0
3342 Over time, many people have reported problems when trying to use the
3343 "minicom" terminal emulation program for serial download. I (wd)
3344 consider minicom to be broken, and recommend not to use it. Under
3345 Unix, I recommend to use C-Kermit for general purpose use (and
3346 especially for kermit binary protocol download ("loadb" command), and
3347 use "cu" for S-Record download ("loads" command).
3349 Nevertheless, if you absolutely want to use it try adding this
3350 configuration to your "File transfer protocols" section:
3352 Name Program Name U/D FullScr IO-Red. Multi
3353 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3354 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3360 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3361 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3363 Building requires a cross environment; it is known to work on
3364 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3365 need gmake since the Makefiles are not compatible with BSD make).
3366 Note that the cross-powerpc package does not install include files;
3367 attempting to build U-Boot will fail because <machine/ansi.h> is
3368 missing. This file has to be installed and patched manually:
3370 # cd /usr/pkg/cross/powerpc-netbsd/include
3372 # ln -s powerpc machine
3373 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3374 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3376 Native builds *don't* work due to incompatibilities between native
3377 and U-Boot include files.
3379 Booting assumes that (the first part of) the image booted is a
3380 stage-2 loader which in turn loads and then invokes the kernel
3381 proper. Loader sources will eventually appear in the NetBSD source
3382 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3383 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3386 Implementation Internals:
3387 =========================
3389 The following is not intended to be a complete description of every
3390 implementation detail. However, it should help to understand the
3391 inner workings of U-Boot and make it easier to port it to custom
3395 Initial Stack, Global Data:
3396 ---------------------------
3398 The implementation of U-Boot is complicated by the fact that U-Boot
3399 starts running out of ROM (flash memory), usually without access to
3400 system RAM (because the memory controller is not initialized yet).
3401 This means that we don't have writable Data or BSS segments, and BSS
3402 is not initialized as zero. To be able to get a C environment working
3403 at all, we have to allocate at least a minimal stack. Implementation
3404 options for this are defined and restricted by the CPU used: Some CPU
3405 models provide on-chip memory (like the IMMR area on MPC8xx and
3406 MPC826x processors), on others (parts of) the data cache can be
3407 locked as (mis-) used as memory, etc.
3409 Chris Hallinan posted a good summary of these issues to the
3410 u-boot-users mailing list:
3412 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3413 From: "Chris Hallinan" <clh@net1plus.com>
3414 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3417 Correct me if I'm wrong, folks, but the way I understand it
3418 is this: Using DCACHE as initial RAM for Stack, etc, does not
3419 require any physical RAM backing up the cache. The cleverness
3420 is that the cache is being used as a temporary supply of
3421 necessary storage before the SDRAM controller is setup. It's
3422 beyond the scope of this list to expain the details, but you
3423 can see how this works by studying the cache architecture and
3424 operation in the architecture and processor-specific manuals.
3426 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3427 is another option for the system designer to use as an
3428 initial stack/ram area prior to SDRAM being available. Either
3429 option should work for you. Using CS 4 should be fine if your
3430 board designers haven't used it for something that would
3431 cause you grief during the initial boot! It is frequently not
3434 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3435 with your processor/board/system design. The default value
3436 you will find in any recent u-boot distribution in
3437 walnut.h should work for you. I'd set it to a value larger
3438 than your SDRAM module. If you have a 64MB SDRAM module, set
3439 it above 400_0000. Just make sure your board has no resources
3440 that are supposed to respond to that address! That code in
3441 start.S has been around a while and should work as is when
3442 you get the config right.
3447 It is essential to remember this, since it has some impact on the C
3448 code for the initialization procedures:
3450 * Initialized global data (data segment) is read-only. Do not attempt
3453 * Do not use any unitialized global data (or implicitely initialized
3454 as zero data - BSS segment) at all - this is undefined, initiali-
3455 zation is performed later (when relocating to RAM).
3457 * Stack space is very limited. Avoid big data buffers or things like
3460 Having only the stack as writable memory limits means we cannot use
3461 normal global data to share information beween the code. But it
3462 turned out that the implementation of U-Boot can be greatly
3463 simplified by making a global data structure (gd_t) available to all
3464 functions. We could pass a pointer to this data as argument to _all_
3465 functions, but this would bloat the code. Instead we use a feature of
3466 the GCC compiler (Global Register Variables) to share the data: we
3467 place a pointer (gd) to the global data into a register which we
3468 reserve for this purpose.
3470 When choosing a register for such a purpose we are restricted by the
3471 relevant (E)ABI specifications for the current architecture, and by
3472 GCC's implementation.
3474 For PowerPC, the following registers have specific use:
3477 R3-R4: parameter passing and return values
3478 R5-R10: parameter passing
3479 R13: small data area pointer
3483 (U-Boot also uses R14 as internal GOT pointer.)
3485 ==> U-Boot will use R29 to hold a pointer to the global data
3487 Note: on PPC, we could use a static initializer (since the
3488 address of the global data structure is known at compile time),
3489 but it turned out that reserving a register results in somewhat
3490 smaller code - although the code savings are not that big (on
3491 average for all boards 752 bytes for the whole U-Boot image,
3492 624 text + 127 data).
3494 On ARM, the following registers are used:
3496 R0: function argument word/integer result
3497 R1-R3: function argument word
3499 R10: stack limit (used only if stack checking if enabled)
3500 R11: argument (frame) pointer
3501 R12: temporary workspace
3504 R15: program counter
3506 ==> U-Boot will use R8 to hold a pointer to the global data
3508 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3509 or current versions of GCC may "optimize" the code too much.
3514 U-Boot runs in system state and uses physical addresses, i.e. the
3515 MMU is not used either for address mapping nor for memory protection.
3517 The available memory is mapped to fixed addresses using the memory
3518 controller. In this process, a contiguous block is formed for each
3519 memory type (Flash, SDRAM, SRAM), even when it consists of several
3520 physical memory banks.
3522 U-Boot is installed in the first 128 kB of the first Flash bank (on
3523 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3524 booting and sizing and initializing DRAM, the code relocates itself
3525 to the upper end of DRAM. Immediately below the U-Boot code some
3526 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3527 configuration setting]. Below that, a structure with global Board
3528 Info data is placed, followed by the stack (growing downward).
3530 Additionally, some exception handler code is copied to the low 8 kB
3531 of DRAM (0x00000000 ... 0x00001FFF).
3533 So a typical memory configuration with 16 MB of DRAM could look like
3536 0x0000 0000 Exception Vector code
3539 0x0000 2000 Free for Application Use
3545 0x00FB FF20 Monitor Stack (Growing downward)
3546 0x00FB FFAC Board Info Data and permanent copy of global data
3547 0x00FC 0000 Malloc Arena
3550 0x00FE 0000 RAM Copy of Monitor Code
3551 ... eventually: LCD or video framebuffer
3552 ... eventually: pRAM (Protected RAM - unchanged by reset)
3553 0x00FF FFFF [End of RAM]
3556 System Initialization:
3557 ----------------------
3559 In the reset configuration, U-Boot starts at the reset entry point
3560 (on most PowerPC systens at address 0x00000100). Because of the reset
3561 configuration for CS0# this is a mirror of the onboard Flash memory.
3562 To be able to re-map memory U-Boot then jumps to its link address.
3563 To be able to implement the initialization code in C, a (small!)
3564 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3565 which provide such a feature like MPC8xx or MPC8260), or in a locked
3566 part of the data cache. After that, U-Boot initializes the CPU core,
3567 the caches and the SIU.
3569 Next, all (potentially) available memory banks are mapped using a
3570 preliminary mapping. For example, we put them on 512 MB boundaries
3571 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3572 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3573 programmed for SDRAM access. Using the temporary configuration, a
3574 simple memory test is run that determines the size of the SDRAM
3577 When there is more than one SDRAM bank, and the banks are of
3578 different size, the largest is mapped first. For equal size, the first
3579 bank (CS2#) is mapped first. The first mapping is always for address
3580 0x00000000, with any additional banks following immediately to create
3581 contiguous memory starting from 0.
3583 Then, the monitor installs itself at the upper end of the SDRAM area
3584 and allocates memory for use by malloc() and for the global Board
3585 Info data; also, the exception vector code is copied to the low RAM
3586 pages, and the final stack is set up.
3588 Only after this relocation will you have a "normal" C environment;
3589 until that you are restricted in several ways, mostly because you are
3590 running from ROM, and because the code will have to be relocated to a
3594 U-Boot Porting Guide:
3595 ----------------------
3597 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3601 int main (int argc, char *argv[])
3603 sighandler_t no_more_time;
3605 signal (SIGALRM, no_more_time);
3606 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3608 if (available_money > available_manpower) {
3609 pay consultant to port U-Boot;
3613 Download latest U-Boot source;
3615 Subscribe to u-boot-users mailing list;
3618 email ("Hi, I am new to U-Boot, how do I get started?");
3622 Read the README file in the top level directory;
3623 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3624 Read the source, Luke;
3627 if (available_money > toLocalCurrency ($2500)) {
3630 Add a lot of aggravation and time;
3633 Create your own board support subdirectory;
3635 Create your own board config file;
3639 Add / modify source code;
3643 email ("Hi, I am having problems...");
3645 Send patch file to Wolfgang;
3650 void no_more_time (int sig)
3659 All contributions to U-Boot should conform to the Linux kernel
3660 coding style; see the file "Documentation/CodingStyle" and the script
3661 "scripts/Lindent" in your Linux kernel source directory. In sources
3662 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3663 spaces before parameters to function calls) is actually used.
3665 Source files originating from a different project (for example the
3666 MTD subsystem) are generally exempt from these guidelines and are not
3667 reformated to ease subsequent migration to newer versions of those
3670 Please note that U-Boot is implemented in C (and to some small parts in
3671 Assembler); no C++ is used, so please do not use C++ style comments (//)
3674 Please also stick to the following formatting rules:
3675 - remove any trailing white space
3676 - use TAB characters for indentation, not spaces
3677 - make sure NOT to use DOS '\r\n' line feeds
3678 - do not add more than 2 empty lines to source files
3679 - do not add trailing empty lines to source files
3681 Submissions which do not conform to the standards may be returned
3682 with a request to reformat the changes.
3688 Since the number of patches for U-Boot is growing, we need to
3689 establish some rules. Submissions which do not conform to these rules
3690 may be rejected, even when they contain important and valuable stuff.
3692 Patches shall be sent to the u-boot-users mailing list.
3694 When you send a patch, please include the following information with
3697 * For bug fixes: a description of the bug and how your patch fixes
3698 this bug. Please try to include a way of demonstrating that the
3699 patch actually fixes something.
3701 * For new features: a description of the feature and your
3704 * A CHANGELOG entry as plaintext (separate from the patch)
3706 * For major contributions, your entry to the CREDITS file
3708 * When you add support for a new board, don't forget to add this
3709 board to the MAKEALL script, too.
3711 * If your patch adds new configuration options, don't forget to
3712 document these in the README file.
3714 * The patch itself. If you are accessing the CVS repository use "cvs
3715 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3716 version of diff does not support these options, then get the latest
3717 version of GNU diff.
3719 The current directory when running this command shall be the top
3720 level directory of the U-Boot source tree, or it's parent directory
3721 (i. e. please make sure that your patch includes sufficient
3722 directory information for the affected files).
3724 We accept patches as plain text, MIME attachments or as uuencoded
3727 * If one logical set of modifications affects or creates several
3728 files, all these changes shall be submitted in a SINGLE patch file.
3730 * Changesets that contain different, unrelated modifications shall be
3731 submitted as SEPARATE patches, one patch per changeset.
3736 * Before sending the patch, run the MAKEALL script on your patched
3737 source tree and make sure that no errors or warnings are reported
3738 for any of the boards.
3740 * Keep your modifications to the necessary minimum: A patch
3741 containing several unrelated changes or arbitrary reformats will be
3742 returned with a request to re-formatting / split it.
3744 * If you modify existing code, make sure that your new code does not
3745 add to the memory footprint of the code ;-) Small is beautiful!
3746 When adding new features, these should compile conditionally only
3747 (using #ifdef), and the resulting code with the new feature
3748 disabled must not need more memory than the old code without your
3751 * Remember that there is a size limit of 40 kB per message on the
3752 u-boot-users mailing list. Compression may help.
projects / karo-tx-uboot.git / blob