2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
140 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
141 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
142 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
143 - mips Files specific to MIPS CPUs
144 - mpc5xx Files specific to Freescale MPC5xx CPUs
145 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
146 - mpc8xx Files specific to Freescale MPC8xx CPUs
147 - mpc8220 Files specific to Freescale MPC8220 CPUs
148 - mpc824x Files specific to Freescale MPC824x CPUs
149 - mpc8260 Files specific to Freescale MPC8260 CPUs
150 - mpc85xx Files specific to Freescale MPC85xx CPUs
151 - nios Files specific to Altera NIOS CPUs
152 - nios2 Files specific to Altera Nios-II CPUs
153 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
154 - pxa Files specific to Intel XScale PXA CPUs
155 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
156 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
157 - disk Code for disk drive partition handling
158 - doc Documentation (don't expect too much)
159 - drivers Commonly used device drivers
160 - dtt Digital Thermometer and Thermostat drivers
161 - examples Example code for standalone applications, etc.
162 - include Header Files
163 - lib_arm Files generic to ARM architecture
164 - lib_avr32 Files generic to AVR32 architecture
165 - lib_generic Files generic to all architectures
166 - lib_i386 Files generic to i386 architecture
167 - lib_m68k Files generic to m68k architecture
168 - lib_mips Files generic to MIPS architecture
169 - lib_nios Files generic to NIOS architecture
170 - lib_ppc Files generic to PowerPC architecture
171 - libfdt Library files to support flattened device trees
172 - net Networking code
173 - post Power On Self Test
174 - rtc Real Time Clock drivers
175 - tools Tools to build S-Record or U-Boot images, etc.
177 Software Configuration:
178 =======================
180 Configuration is usually done using C preprocessor defines; the
181 rationale behind that is to avoid dead code whenever possible.
183 There are two classes of configuration variables:
185 * Configuration _OPTIONS_:
186 These are selectable by the user and have names beginning with
189 * Configuration _SETTINGS_:
190 These depend on the hardware etc. and should not be meddled with if
191 you don't know what you're doing; they have names beginning with
194 Later we will add a configuration tool - probably similar to or even
195 identical to what's used for the Linux kernel. Right now, we have to
196 do the configuration by hand, which means creating some symbolic
197 links and editing some configuration files. We use the TQM8xxL boards
201 Selection of Processor Architecture and Board Type:
202 ---------------------------------------------------
204 For all supported boards there are ready-to-use default
205 configurations available; just type "make <board_name>_config".
207 Example: For a TQM823L module type:
212 For the Cogent platform, you need to specify the cpu type as well;
213 e.g. "make cogent_mpc8xx_config". And also configure the cogent
214 directory according to the instructions in cogent/README.
217 Configuration Options:
218 ----------------------
220 Configuration depends on the combination of board and CPU type; all
221 such information is kept in a configuration file
222 "include/configs/<board_name>.h".
224 Example: For a TQM823L module, all configuration settings are in
225 "include/configs/TQM823L.h".
228 Many of the options are named exactly as the corresponding Linux
229 kernel configuration options. The intention is to make it easier to
230 build a config tool - later.
233 The following options need to be configured:
235 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
237 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
239 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
240 Define exactly one, e.g. CONFIG_ATSTK1002
242 - CPU Module Type: (if CONFIG_COGENT is defined)
243 Define exactly one of
245 --- FIXME --- not tested yet:
246 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
247 CONFIG_CMA287_23, CONFIG_CMA287_50
249 - Motherboard Type: (if CONFIG_COGENT is defined)
250 Define exactly one of
251 CONFIG_CMA101, CONFIG_CMA102
253 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
254 Define one or more of
257 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
258 Define one or more of
259 CONFIG_LCD_HEARTBEAT - update a character position on
260 the lcd display every second with
263 - Board flavour: (if CONFIG_MPC8260ADS is defined)
266 CFG_8260ADS - original MPC8260ADS
267 CFG_8266ADS - MPC8266ADS
268 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
269 CFG_8272ADS - MPC8272ADS
271 - MPC824X Family Member (if CONFIG_MPC824X is defined)
272 Define exactly one of
273 CONFIG_MPC8240, CONFIG_MPC8245
275 - 8xx CPU Options: (if using an MPC8xx cpu)
276 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
277 get_gclk_freq() cannot work
278 e.g. if there is no 32KHz
279 reference PIT/RTC clock
280 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
283 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
286 CONFIG_8xx_CPUCLK_DEFAULT
287 See doc/README.MPC866
291 Define this to measure the actual CPU clock instead
292 of relying on the correctness of the configured
293 values. Mostly useful for board bringup to make sure
294 the PLL is locked at the intended frequency. Note
295 that this requires a (stable) reference clock (32 kHz
296 RTC clock or CFG_8XX_XIN)
298 - Intel Monahans options:
299 CFG_MONAHANS_RUN_MODE_OSC_RATIO
301 Defines the Monahans run mode to oscillator
302 ratio. Valid values are 8, 16, 24, 31. The core
303 frequency is this value multiplied by 13 MHz.
305 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
307 Defines the Monahans turbo mode to oscillator
308 ratio. Valid values are 1 (default if undefined) and
309 2. The core frequency as calculated above is multiplied
312 - Linux Kernel Interface:
315 U-Boot stores all clock information in Hz
316 internally. For binary compatibility with older Linux
317 kernels (which expect the clocks passed in the
318 bd_info data to be in MHz) the environment variable
319 "clocks_in_mhz" can be defined so that U-Boot
320 converts clock data to MHZ before passing it to the
322 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
323 "clocks_in_mhz=1" is automatically included in the
326 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
328 When transfering memsize parameter to linux, some versions
329 expect it to be in bytes, others in MB.
330 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
332 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
334 New kernel versions are expecting firmware settings to be
335 passed using flattened device trees (based on open firmware
339 * New libfdt-based support
340 * Adds the "fdt" command
341 * The bootm command automatically updates the fdt
344 * Deprecated, see CONFIG_OF_LIBFDT
345 * Original ft_build.c-based support
346 * Automatically modifies the dft as part of the bootm command
347 * The environment variable "disable_of", when set,
348 disables this functionality.
350 OF_CPU - The proper name of the cpus node.
351 OF_SOC - The proper name of the soc node.
352 OF_TBCLK - The timebase frequency.
353 OF_STDOUT_PATH - The path to the console device
355 boards with QUICC Engines require OF_QE to set UCC mac addresses
359 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
360 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
361 will have a copy of the bd_t. Space should be
362 pre-allocated in the dts for the bd_t.
364 CONFIG_OF_HAS_UBOOT_ENV
366 * CONFIG_OF_LIBFDT - enables the "fdt env" command
367 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
368 will have a copy of u-boot's environment variables
370 CONFIG_OF_BOARD_SETUP
372 Board code has addition modification that it wants to make
373 to the flat device tree before handing it off to the kernel
377 This define fills in the correct boot cpu in the boot
378 param header, the default value is zero if undefined.
383 Define this if you want support for Amba PrimeCell PL010 UARTs.
387 Define this if you want support for Amba PrimeCell PL011 UARTs.
391 If you have Amba PrimeCell PL011 UARTs, set this variable to
392 the clock speed of the UARTs.
396 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
397 define this to a list of base addresses for each (supported)
398 port. See e.g. include/configs/versatile.h
402 Depending on board, define exactly one serial port
403 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
404 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
405 console by defining CONFIG_8xx_CONS_NONE
407 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
408 port routines must be defined elsewhere
409 (i.e. serial_init(), serial_getc(), ...)
412 Enables console device for a color framebuffer. Needs following
413 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
414 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
416 VIDEO_HW_RECTFILL graphic chip supports
419 VIDEO_HW_BITBLT graphic chip supports
420 bit-blit (cf. smiLynxEM)
421 VIDEO_VISIBLE_COLS visible pixel columns
423 VIDEO_VISIBLE_ROWS visible pixel rows
424 VIDEO_PIXEL_SIZE bytes per pixel
425 VIDEO_DATA_FORMAT graphic data format
426 (0-5, cf. cfb_console.c)
427 VIDEO_FB_ADRS framebuffer address
428 VIDEO_KBD_INIT_FCT keyboard int fct
429 (i.e. i8042_kbd_init())
430 VIDEO_TSTC_FCT test char fct
432 VIDEO_GETC_FCT get char fct
434 CONFIG_CONSOLE_CURSOR cursor drawing on/off
435 (requires blink timer
437 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
438 CONFIG_CONSOLE_TIME display time/date info in
440 (requires CONFIG_CMD_DATE)
441 CONFIG_VIDEO_LOGO display Linux logo in
443 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
444 linux_logo.h for logo.
445 Requires CONFIG_VIDEO_LOGO
446 CONFIG_CONSOLE_EXTRA_INFO
447 addional board info beside
450 When CONFIG_CFB_CONSOLE is defined, video console is
451 default i/o. Serial console can be forced with
452 environment 'console=serial'.
454 When CONFIG_SILENT_CONSOLE is defined, all console
455 messages (by U-Boot and Linux!) can be silenced with
456 the "silent" environment variable. See
457 doc/README.silent for more information.
460 CONFIG_BAUDRATE - in bps
461 Select one of the baudrates listed in
462 CFG_BAUDRATE_TABLE, see below.
463 CFG_BRGCLK_PRESCALE, baudrate prescale
465 - Interrupt driven serial port input:
466 CONFIG_SERIAL_SOFTWARE_FIFO
469 Use an interrupt handler for receiving data on the
470 serial port. It also enables using hardware handshake
471 (RTS/CTS) and UART's built-in FIFO. Set the number of
472 bytes the interrupt driven input buffer should have.
474 Leave undefined to disable this feature, including
475 disable the buffer and hardware handshake.
477 - Console UART Number:
481 If defined internal UART1 (and not UART0) is used
482 as default U-Boot console.
484 - Boot Delay: CONFIG_BOOTDELAY - in seconds
485 Delay before automatically booting the default image;
486 set to -1 to disable autoboot.
488 See doc/README.autoboot for these options that
489 work with CONFIG_BOOTDELAY. None are required.
490 CONFIG_BOOT_RETRY_TIME
491 CONFIG_BOOT_RETRY_MIN
492 CONFIG_AUTOBOOT_KEYED
493 CONFIG_AUTOBOOT_PROMPT
494 CONFIG_AUTOBOOT_DELAY_STR
495 CONFIG_AUTOBOOT_STOP_STR
496 CONFIG_AUTOBOOT_DELAY_STR2
497 CONFIG_AUTOBOOT_STOP_STR2
498 CONFIG_ZERO_BOOTDELAY_CHECK
499 CONFIG_RESET_TO_RETRY
503 Only needed when CONFIG_BOOTDELAY is enabled;
504 define a command string that is automatically executed
505 when no character is read on the console interface
506 within "Boot Delay" after reset.
509 This can be used to pass arguments to the bootm
510 command. The value of CONFIG_BOOTARGS goes into the
511 environment value "bootargs".
513 CONFIG_RAMBOOT and CONFIG_NFSBOOT
514 The value of these goes into the environment as
515 "ramboot" and "nfsboot" respectively, and can be used
516 as a convenience, when switching between booting from
522 When this option is #defined, the existence of the
523 environment variable "preboot" will be checked
524 immediately before starting the CONFIG_BOOTDELAY
525 countdown and/or running the auto-boot command resp.
526 entering interactive mode.
528 This feature is especially useful when "preboot" is
529 automatically generated or modified. For an example
530 see the LWMON board specific code: here "preboot" is
531 modified when the user holds down a certain
532 combination of keys on the (special) keyboard when
535 - Serial Download Echo Mode:
537 If defined to 1, all characters received during a
538 serial download (using the "loads" command) are
539 echoed back. This might be needed by some terminal
540 emulations (like "cu"), but may as well just take
541 time on others. This setting #define's the initial
542 value of the "loads_echo" environment variable.
544 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
546 Select one of the baudrates listed in
547 CFG_BAUDRATE_TABLE, see below.
550 Monitor commands can be included or excluded
551 from the build by using the #include files
552 "config_cmd_all.h" and #undef'ing unwanted
553 commands, or using "config_cmd_default.h"
554 and augmenting with additional #define's
557 The default command configuration includes all commands
558 except those marked below with a "*".
560 CONFIG_CMD_ASKENV * ask for env variable
561 CONFIG_CMD_AUTOSCRIPT Autoscript Support
562 CONFIG_CMD_BDI bdinfo
563 CONFIG_CMD_BEDBUG * Include BedBug Debugger
564 CONFIG_CMD_BMP * BMP support
565 CONFIG_CMD_BSP * Board specific commands
566 CONFIG_CMD_BOOTD bootd
567 CONFIG_CMD_CACHE * icache, dcache
568 CONFIG_CMD_CONSOLE coninfo
569 CONFIG_CMD_DATE * support for RTC, date/time...
570 CONFIG_CMD_DHCP * DHCP support
571 CONFIG_CMD_DIAG * Diagnostics
572 CONFIG_CMD_DOC * Disk-On-Chip Support
573 CONFIG_CMD_DTT * Digital Therm and Thermostat
574 CONFIG_CMD_ECHO echo arguments
575 CONFIG_CMD_EEPROM * EEPROM read/write support
576 CONFIG_CMD_ELF * bootelf, bootvx
577 CONFIG_CMD_ENV saveenv
578 CONFIG_CMD_FDC * Floppy Disk Support
579 CONFIG_CMD_FAT * FAT partition support
580 CONFIG_CMD_FDOS * Dos diskette Support
581 CONFIG_CMD_FLASH flinfo, erase, protect
582 CONFIG_CMD_FPGA FPGA device initialization support
583 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
584 CONFIG_CMD_I2C * I2C serial bus support
585 CONFIG_CMD_IDE * IDE harddisk support
586 CONFIG_CMD_IMI iminfo
587 CONFIG_CMD_IMLS List all found images
588 CONFIG_CMD_IMMAP * IMMR dump support
589 CONFIG_CMD_IRQ * irqinfo
590 CONFIG_CMD_ITEST Integer/string test of 2 values
591 CONFIG_CMD_JFFS2 * JFFS2 Support
592 CONFIG_CMD_KGDB * kgdb
593 CONFIG_CMD_LOADB loadb
594 CONFIG_CMD_LOADS loads
595 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
597 CONFIG_CMD_MISC Misc functions like sleep etc
598 CONFIG_CMD_MMC * MMC memory mapped support
599 CONFIG_CMD_MII * MII utility commands
600 CONFIG_CMD_NAND * NAND support
601 CONFIG_CMD_NET bootp, tftpboot, rarpboot
602 CONFIG_CMD_PCI * pciinfo
603 CONFIG_CMD_PCMCIA * PCMCIA support
604 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
606 CONFIG_CMD_PORTIO * Port I/O
607 CONFIG_CMD_REGINFO * Register dump
608 CONFIG_CMD_RUN run command in env variable
609 CONFIG_CMD_SAVES * save S record dump
610 CONFIG_CMD_SCSI * SCSI Support
611 CONFIG_CMD_SDRAM * print SDRAM configuration information
612 (requires CONFIG_CMD_I2C)
613 CONFIG_CMD_SETGETDCR Support for DCR Register access
615 CONFIG_CMD_SPI * SPI serial bus support
616 CONFIG_CMD_USB * USB support
617 CONFIG_CMD_VFD * VFD support (TRAB)
618 CONFIG_CMD_BSP * Board SPecific functions
619 CONFIG_CMD_CDP * Cisco Discover Protocol support
620 CONFIG_CMD_FSL * Microblaze FSL support
623 EXAMPLE: If you want all functions except of network
624 support you can write:
626 #include "config_cmd_all.h"
627 #undef CONFIG_CMD_NET
630 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
632 Note: Don't enable the "icache" and "dcache" commands
633 (configuration option CONFIG_CMD_CACHE) unless you know
634 what you (and your U-Boot users) are doing. Data
635 cache cannot be enabled on systems like the 8xx or
636 8260 (where accesses to the IMMR region must be
637 uncached), and it cannot be disabled on all other
638 systems where we (mis-) use the data cache to hold an
639 initial stack and some data.
642 XXX - this list needs to get updated!
646 If this variable is defined, it enables watchdog
647 support. There must be support in the platform specific
648 code for a watchdog. For the 8xx and 8260 CPUs, the
649 SIU Watchdog feature is enabled in the SYPCR
653 CONFIG_VERSION_VARIABLE
654 If this variable is defined, an environment variable
655 named "ver" is created by U-Boot showing the U-Boot
656 version as printed by the "version" command.
657 This variable is readonly.
661 When CONFIG_CMD_DATE is selected, the type of the RTC
662 has to be selected, too. Define exactly one of the
665 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
666 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
667 CONFIG_RTC_MC146818 - use MC146818 RTC
668 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
669 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
670 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
671 CONFIG_RTC_DS164x - use Dallas DS164x RTC
672 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
673 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
675 Note that if the RTC uses I2C, then the I2C interface
676 must also be configured. See I2C Support, below.
680 When CONFIG_TIMESTAMP is selected, the timestamp
681 (date and time) of an image is printed by image
682 commands like bootm or iminfo. This option is
683 automatically enabled when you select CONFIG_CMD_DATE .
686 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
687 and/or CONFIG_ISO_PARTITION
689 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
690 CONFIG_CMD_SCSI) you must configure support for at least
691 one partition type as well.
694 CONFIG_IDE_RESET_ROUTINE - this is defined in several
695 board configurations files but used nowhere!
697 CONFIG_IDE_RESET - is this is defined, IDE Reset will
698 be performed by calling the function
699 ide_set_reset(int reset)
700 which has to be defined in a board specific file
705 Set this to enable ATAPI support.
710 Set this to enable support for disks larger than 137GB
711 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
712 Whithout these , LBA48 support uses 32bit variables and will 'only'
713 support disks up to 2.1TB.
716 When enabled, makes the IDE subsystem use 64bit sector addresses.
720 At the moment only there is only support for the
721 SYM53C8XX SCSI controller; define
722 CONFIG_SCSI_SYM53C8XX to enable it.
724 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
725 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
726 CFG_SCSI_MAX_LUN] can be adjusted to define the
727 maximum numbers of LUNs, SCSI ID's and target
729 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
731 - NETWORK Support (PCI):
733 Support for Intel 8254x gigabit chips.
736 Support for Intel 82557/82559/82559ER chips.
737 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
738 write routine for first time initialisation.
741 Support for Digital 2114x chips.
742 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
743 modem chip initialisation (KS8761/QS6611).
746 Support for National dp83815 chips.
749 Support for National dp8382[01] gigabit chips.
751 - NETWORK Support (other):
753 CONFIG_DRIVER_LAN91C96
754 Support for SMSC's LAN91C96 chips.
757 Define this to hold the physical address
758 of the LAN91C96's I/O space
760 CONFIG_LAN91C96_USE_32_BIT
761 Define this to enable 32 bit addressing
763 CONFIG_DRIVER_SMC91111
764 Support for SMSC's LAN91C111 chip
767 Define this to hold the physical address
768 of the device (I/O space)
770 CONFIG_SMC_USE_32_BIT
771 Define this if data bus is 32 bits
773 CONFIG_SMC_USE_IOFUNCS
774 Define this to use i/o functions instead of macros
775 (some hardware wont work with macros)
778 At the moment only the UHCI host controller is
779 supported (PIP405, MIP405, MPC5200); define
780 CONFIG_USB_UHCI to enable it.
781 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
782 and define CONFIG_USB_STORAGE to enable the USB
785 Supported are USB Keyboards and USB Floppy drives
787 MPC5200 USB requires additional defines:
789 for 528 MHz Clock: 0x0001bbbb
791 for differential drivers: 0x00001000
792 for single ended drivers: 0x00005000
794 May be defined to allow interrupt polling
795 instead of using asynchronous interrupts
798 Define the below if you wish to use the USB console.
799 Once firmware is rebuilt from a serial console issue the
800 command "setenv stdin usbtty; setenv stdout usbtty" and
801 attach your usb cable. The Unix command "dmesg" should print
802 it has found a new device. The environment variable usbtty
803 can be set to gserial or cdc_acm to enable your device to
804 appear to a USB host as a Linux gserial device or a
805 Common Device Class Abstract Control Model serial device.
806 If you select usbtty = gserial you should be able to enumerate
808 # modprobe usbserial vendor=0xVendorID product=0xProductID
809 else if using cdc_acm, simply setting the environment
810 variable usbtty to be cdc_acm should suffice. The following
811 might be defined in YourBoardName.h
814 Define this to build a UDC device
817 Define this to have a tty type of device available to
818 talk to the UDC device
820 CFG_CONSOLE_IS_IN_ENV
821 Define this if you want stdin, stdout &/or stderr to
825 CFG_USB_EXTC_CLK 0xBLAH
826 Derive USB clock from external clock "blah"
827 - CFG_USB_EXTC_CLK 0x02
829 CFG_USB_BRG_CLK 0xBLAH
830 Derive USB clock from brgclk
831 - CFG_USB_BRG_CLK 0x04
833 If you have a USB-IF assigned VendorID then you may wish to
834 define your own vendor specific values either in BoardName.h
835 or directly in usbd_vendor_info.h. If you don't define
836 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
837 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
838 should pretend to be a Linux device to it's target host.
840 CONFIG_USBD_MANUFACTURER
841 Define this string as the name of your company for
842 - CONFIG_USBD_MANUFACTURER "my company"
844 CONFIG_USBD_PRODUCT_NAME
845 Define this string as the name of your product
846 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
849 Define this as your assigned Vendor ID from the USB
850 Implementors Forum. This *must* be a genuine Vendor ID
851 to avoid polluting the USB namespace.
852 - CONFIG_USBD_VENDORID 0xFFFF
854 CONFIG_USBD_PRODUCTID
855 Define this as the unique Product ID
857 - CONFIG_USBD_PRODUCTID 0xFFFF
861 The MMC controller on the Intel PXA is supported. To
862 enable this define CONFIG_MMC. The MMC can be
863 accessed from the boot prompt by mapping the device
864 to physical memory similar to flash. Command line is
865 enabled with CONFIG_CMD_MMC. The MMC driver also works with
866 the FAT fs. This is enabled with CONFIG_CMD_FAT.
868 - Journaling Flash filesystem support:
869 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
870 CONFIG_JFFS2_NAND_DEV
871 Define these for a default partition on a NAND device
873 CFG_JFFS2_FIRST_SECTOR,
874 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
875 Define these for a default partition on a NOR device
878 Define this to create an own partition. You have to provide a
879 function struct part_info* jffs2_part_info(int part_num)
881 If you define only one JFFS2 partition you may also want to
882 #define CFG_JFFS_SINGLE_PART 1
883 to disable the command chpart. This is the default when you
884 have not defined a custom partition
889 Define this to enable standard (PC-Style) keyboard
893 Standard PC keyboard driver with US (is default) and
894 GERMAN key layout (switch via environment 'keymap=de') support.
895 Export function i8042_kbd_init, i8042_tstc and i8042_getc
896 for cfb_console. Supports cursor blinking.
901 Define this to enable video support (for output to
906 Enable Chips & Technologies 69000 Video chip
908 CONFIG_VIDEO_SMI_LYNXEM
909 Enable Silicon Motion SMI 712/710/810 Video chip. The
910 video output is selected via environment 'videoout'
911 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
914 For the CT69000 and SMI_LYNXEM drivers, videomode is
915 selected via environment 'videomode'. Two diferent ways
917 - "videomode=num" 'num' is a standard LiLo mode numbers.
918 Following standard modes are supported (* is default):
920 Colors 640x480 800x600 1024x768 1152x864 1280x1024
921 -------------+---------------------------------------------
922 8 bits | 0x301* 0x303 0x305 0x161 0x307
923 15 bits | 0x310 0x313 0x316 0x162 0x319
924 16 bits | 0x311 0x314 0x317 0x163 0x31A
925 24 bits | 0x312 0x315 0x318 ? 0x31B
926 -------------+---------------------------------------------
927 (i.e. setenv videomode 317; saveenv; reset;)
929 - "videomode=bootargs" all the video parameters are parsed
930 from the bootargs. (See drivers/video/videomodes.c)
933 CONFIG_VIDEO_SED13806
934 Enable Epson SED13806 driver. This driver supports 8bpp
935 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
936 or CONFIG_VIDEO_SED13806_16BPP
941 Define this to enable a custom keyboard support.
942 This simply calls drv_keyboard_init() which must be
943 defined in your board-specific files.
944 The only board using this so far is RBC823.
946 - LCD Support: CONFIG_LCD
948 Define this to enable LCD support (for output to LCD
949 display); also select one of the supported displays
950 by defining one of these:
952 CONFIG_NEC_NL6448AC33:
954 NEC NL6448AC33-18. Active, color, single scan.
956 CONFIG_NEC_NL6448BC20
958 NEC NL6448BC20-08. 6.5", 640x480.
959 Active, color, single scan.
961 CONFIG_NEC_NL6448BC33_54
963 NEC NL6448BC33-54. 10.4", 640x480.
964 Active, color, single scan.
968 Sharp 320x240. Active, color, single scan.
969 It isn't 16x9, and I am not sure what it is.
971 CONFIG_SHARP_LQ64D341
973 Sharp LQ64D341 display, 640x480.
974 Active, color, single scan.
978 HLD1045 display, 640x480.
979 Active, color, single scan.
983 Optrex CBL50840-2 NF-FW 99 22 M5
985 Hitachi LMG6912RPFC-00T
989 320x240. Black & white.
991 Normally display is black on white background; define
992 CFG_WHITE_ON_BLACK to get it inverted.
994 - Splash Screen Support: CONFIG_SPLASH_SCREEN
996 If this option is set, the environment is checked for
997 a variable "splashimage". If found, the usual display
998 of logo, copyright and system information on the LCD
999 is suppressed and the BMP image at the address
1000 specified in "splashimage" is loaded instead. The
1001 console is redirected to the "nulldev", too. This
1002 allows for a "silent" boot where a splash screen is
1003 loaded very quickly after power-on.
1005 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1007 If this option is set, additionally to standard BMP
1008 images, gzipped BMP images can be displayed via the
1009 splashscreen support or the bmp command.
1011 - Compression support:
1014 If this option is set, support for bzip2 compressed
1015 images is included. If not, only uncompressed and gzip
1016 compressed images are supported.
1018 NOTE: the bzip2 algorithm requires a lot of RAM, so
1019 the malloc area (as defined by CFG_MALLOC_LEN) should
1025 The address of PHY on MII bus.
1027 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1029 The clock frequency of the MII bus
1033 If this option is set, support for speed/duplex
1034 detection of Gigabit PHY is included.
1036 CONFIG_PHY_RESET_DELAY
1038 Some PHY like Intel LXT971A need extra delay after
1039 reset before any MII register access is possible.
1040 For such PHY, set this option to the usec delay
1041 required. (minimum 300usec for LXT971A)
1043 CONFIG_PHY_CMD_DELAY (ppc4xx)
1045 Some PHY like Intel LXT971A need extra delay after
1046 command issued before MII status register can be read
1053 Define a default value for ethernet address to use
1054 for the respective ethernet interface, in case this
1055 is not determined automatically.
1060 Define a default value for the IP address to use for
1061 the default ethernet interface, in case this is not
1062 determined through e.g. bootp.
1064 - Server IP address:
1067 Defines a default value for theIP address of a TFTP
1068 server to contact when using the "tftboot" command.
1070 - Multicast TFTP Mode:
1073 Defines whether you want to support multicast TFTP as per
1074 rfc-2090; for example to work with atftp. Lets lots of targets
1075 tftp down the same boot image concurrently. Note: the ethernet
1076 driver in use must provide a function: mcast() to join/leave a
1079 CONFIG_BOOTP_RANDOM_DELAY
1080 - BOOTP Recovery Mode:
1081 CONFIG_BOOTP_RANDOM_DELAY
1083 If you have many targets in a network that try to
1084 boot using BOOTP, you may want to avoid that all
1085 systems send out BOOTP requests at precisely the same
1086 moment (which would happen for instance at recovery
1087 from a power failure, when all systems will try to
1088 boot, thus flooding the BOOTP server. Defining
1089 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1090 inserted before sending out BOOTP requests. The
1091 following delays are inserted then:
1093 1st BOOTP request: delay 0 ... 1 sec
1094 2nd BOOTP request: delay 0 ... 2 sec
1095 3rd BOOTP request: delay 0 ... 4 sec
1097 BOOTP requests: delay 0 ... 8 sec
1099 - DHCP Advanced Options:
1100 You can fine tune the DHCP functionality by defining
1101 CONFIG_BOOTP_* symbols:
1103 CONFIG_BOOTP_SUBNETMASK
1104 CONFIG_BOOTP_GATEWAY
1105 CONFIG_BOOTP_HOSTNAME
1106 CONFIG_BOOTP_NISDOMAIN
1107 CONFIG_BOOTP_BOOTPATH
1108 CONFIG_BOOTP_BOOTFILESIZE
1111 CONFIG_BOOTP_SEND_HOSTNAME
1112 CONFIG_BOOTP_NTPSERVER
1113 CONFIG_BOOTP_TIMEOFFSET
1114 CONFIG_BOOTP_VENDOREX
1116 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1117 environment variable, not the BOOTP server.
1119 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1120 serverip from a DHCP server, it is possible that more
1121 than one DNS serverip is offered to the client.
1122 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1123 serverip will be stored in the additional environment
1124 variable "dnsip2". The first DNS serverip is always
1125 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1128 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1129 to do a dynamic update of a DNS server. To do this, they
1130 need the hostname of the DHCP requester.
1131 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1132 of the "hostname" environment variable is passed as
1133 option 12 to the DHCP server.
1136 CONFIG_CDP_DEVICE_ID
1138 The device id used in CDP trigger frames.
1140 CONFIG_CDP_DEVICE_ID_PREFIX
1142 A two character string which is prefixed to the MAC address
1147 A printf format string which contains the ascii name of
1148 the port. Normally is set to "eth%d" which sets
1149 eth0 for the first ethernet, eth1 for the second etc.
1151 CONFIG_CDP_CAPABILITIES
1153 A 32bit integer which indicates the device capabilities;
1154 0x00000010 for a normal host which does not forwards.
1158 An ascii string containing the version of the software.
1162 An ascii string containing the name of the platform.
1166 A 32bit integer sent on the trigger.
1168 CONFIG_CDP_POWER_CONSUMPTION
1170 A 16bit integer containing the power consumption of the
1171 device in .1 of milliwatts.
1173 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1175 A byte containing the id of the VLAN.
1177 - Status LED: CONFIG_STATUS_LED
1179 Several configurations allow to display the current
1180 status using a LED. For instance, the LED will blink
1181 fast while running U-Boot code, stop blinking as
1182 soon as a reply to a BOOTP request was received, and
1183 start blinking slow once the Linux kernel is running
1184 (supported by a status LED driver in the Linux
1185 kernel). Defining CONFIG_STATUS_LED enables this
1188 - CAN Support: CONFIG_CAN_DRIVER
1190 Defining CONFIG_CAN_DRIVER enables CAN driver support
1191 on those systems that support this (optional)
1192 feature, like the TQM8xxL modules.
1194 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1196 These enable I2C serial bus commands. Defining either of
1197 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1198 include the appropriate I2C driver for the selected cpu.
1200 This will allow you to use i2c commands at the u-boot
1201 command line (as long as you set CONFIG_CMD_I2C in
1202 CONFIG_COMMANDS) and communicate with i2c based realtime
1203 clock chips. See common/cmd_i2c.c for a description of the
1204 command line interface.
1206 CONFIG_I2C_CMD_TREE is a recommended option that places
1207 all I2C commands under a single 'i2c' root command. The
1208 older 'imm', 'imd', 'iprobe' etc. commands are considered
1209 deprecated and may disappear in the future.
1211 CONFIG_HARD_I2C selects a hardware I2C controller.
1213 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1214 bit-banging) driver instead of CPM or similar hardware
1217 There are several other quantities that must also be
1218 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1220 In both cases you will need to define CFG_I2C_SPEED
1221 to be the frequency (in Hz) at which you wish your i2c bus
1222 to run and CFG_I2C_SLAVE to be the address of this node (ie
1223 the cpu's i2c node address).
1225 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1226 sets the cpu up as a master node and so its address should
1227 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1228 p.16-473). So, set CFG_I2C_SLAVE to 0.
1230 That's all that's required for CONFIG_HARD_I2C.
1232 If you use the software i2c interface (CONFIG_SOFT_I2C)
1233 then the following macros need to be defined (examples are
1234 from include/configs/lwmon.h):
1238 (Optional). Any commands necessary to enable the I2C
1239 controller or configure ports.
1241 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1245 (Only for MPC8260 CPU). The I/O port to use (the code
1246 assumes both bits are on the same port). Valid values
1247 are 0..3 for ports A..D.
1251 The code necessary to make the I2C data line active
1252 (driven). If the data line is open collector, this
1255 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1259 The code necessary to make the I2C data line tri-stated
1260 (inactive). If the data line is open collector, this
1263 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1267 Code that returns TRUE if the I2C data line is high,
1270 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1274 If <bit> is TRUE, sets the I2C data line high. If it
1275 is FALSE, it clears it (low).
1277 eg: #define I2C_SDA(bit) \
1278 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1279 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1283 If <bit> is TRUE, sets the I2C clock line high. If it
1284 is FALSE, it clears it (low).
1286 eg: #define I2C_SCL(bit) \
1287 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1288 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1292 This delay is invoked four times per clock cycle so this
1293 controls the rate of data transfer. The data rate thus
1294 is 1 / (I2C_DELAY * 4). Often defined to be something
1297 #define I2C_DELAY udelay(2)
1301 When a board is reset during an i2c bus transfer
1302 chips might think that the current transfer is still
1303 in progress. On some boards it is possible to access
1304 the i2c SCLK line directly, either by using the
1305 processor pin as a GPIO or by having a second pin
1306 connected to the bus. If this option is defined a
1307 custom i2c_init_board() routine in boards/xxx/board.c
1308 is run early in the boot sequence.
1310 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1312 This option enables configuration of bi_iic_fast[] flags
1313 in u-boot bd_info structure based on u-boot environment
1314 variable "i2cfast". (see also i2cfast)
1316 CONFIG_I2C_MULTI_BUS
1318 This option allows the use of multiple I2C buses, each of which
1319 must have a controller. At any point in time, only one bus is
1320 active. To switch to a different bus, use the 'i2c dev' command.
1321 Note that bus numbering is zero-based.
1325 This option specifies a list of I2C devices that will be skipped
1326 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1327 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1328 pairs. Otherwise, specify a 1D array of device addresses
1331 #undef CONFIG_I2C_MULTI_BUS
1332 #define CFG_I2C_NOPROBES {0x50,0x68}
1334 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1336 #define CONFIG_I2C_MULTI_BUS
1337 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1339 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1343 If defined, then this indicates the I2C bus number for DDR SPD.
1344 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1348 If defined, then this indicates the I2C bus number for the RTC.
1349 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1353 If defined, then this indicates the I2C bus number for the DTT.
1354 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1358 Define this option if you want to use Freescale's I2C driver in
1359 drivers/i2c/fsl_i2c.c.
1362 - SPI Support: CONFIG_SPI
1364 Enables SPI driver (so far only tested with
1365 SPI EEPROM, also an instance works with Crystal A/D and
1366 D/As on the SACSng board)
1370 Enables extended (16-bit) SPI EEPROM addressing.
1371 (symmetrical to CONFIG_I2C_X)
1375 Enables a software (bit-bang) SPI driver rather than
1376 using hardware support. This is a general purpose
1377 driver that only requires three general I/O port pins
1378 (two outputs, one input) to function. If this is
1379 defined, the board configuration must define several
1380 SPI configuration items (port pins to use, etc). For
1381 an example, see include/configs/sacsng.h.
1385 Enables a hardware SPI driver for general-purpose reads
1386 and writes. As with CONFIG_SOFT_SPI, the board configuration
1387 must define a list of chip-select function pointers.
1388 Currently supported on some MPC8xxx processors. For an
1389 example, see include/configs/mpc8349emds.h.
1391 - FPGA Support: CONFIG_FPGA
1393 Enables FPGA subsystem.
1395 CONFIG_FPGA_<vendor>
1397 Enables support for specific chip vendors.
1400 CONFIG_FPGA_<family>
1402 Enables support for FPGA family.
1403 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1407 Specify the number of FPGA devices to support.
1409 CFG_FPGA_PROG_FEEDBACK
1411 Enable printing of hash marks during FPGA configuration.
1415 Enable checks on FPGA configuration interface busy
1416 status by the configuration function. This option
1417 will require a board or device specific function to
1422 If defined, a function that provides delays in the FPGA
1423 configuration driver.
1425 CFG_FPGA_CHECK_CTRLC
1426 Allow Control-C to interrupt FPGA configuration
1428 CFG_FPGA_CHECK_ERROR
1430 Check for configuration errors during FPGA bitfile
1431 loading. For example, abort during Virtex II
1432 configuration if the INIT_B line goes low (which
1433 indicated a CRC error).
1437 Maximum time to wait for the INIT_B line to deassert
1438 after PROB_B has been deasserted during a Virtex II
1439 FPGA configuration sequence. The default time is 500
1444 Maximum time to wait for BUSY to deassert during
1445 Virtex II FPGA configuration. The default is 5 mS.
1447 CFG_FPGA_WAIT_CONFIG
1449 Time to wait after FPGA configuration. The default is
1452 - Configuration Management:
1455 If defined, this string will be added to the U-Boot
1456 version information (U_BOOT_VERSION)
1458 - Vendor Parameter Protection:
1460 U-Boot considers the values of the environment
1461 variables "serial#" (Board Serial Number) and
1462 "ethaddr" (Ethernet Address) to be parameters that
1463 are set once by the board vendor / manufacturer, and
1464 protects these variables from casual modification by
1465 the user. Once set, these variables are read-only,
1466 and write or delete attempts are rejected. You can
1467 change this behviour:
1469 If CONFIG_ENV_OVERWRITE is #defined in your config
1470 file, the write protection for vendor parameters is
1471 completely disabled. Anybody can change or delete
1474 Alternatively, if you #define _both_ CONFIG_ETHADDR
1475 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1476 ethernet address is installed in the environment,
1477 which can be changed exactly ONCE by the user. [The
1478 serial# is unaffected by this, i. e. it remains
1484 Define this variable to enable the reservation of
1485 "protected RAM", i. e. RAM which is not overwritten
1486 by U-Boot. Define CONFIG_PRAM to hold the number of
1487 kB you want to reserve for pRAM. You can overwrite
1488 this default value by defining an environment
1489 variable "pram" to the number of kB you want to
1490 reserve. Note that the board info structure will
1491 still show the full amount of RAM. If pRAM is
1492 reserved, a new environment variable "mem" will
1493 automatically be defined to hold the amount of
1494 remaining RAM in a form that can be passed as boot
1495 argument to Linux, for instance like that:
1497 setenv bootargs ... mem=\${mem}
1500 This way you can tell Linux not to use this memory,
1501 either, which results in a memory region that will
1502 not be affected by reboots.
1504 *WARNING* If your board configuration uses automatic
1505 detection of the RAM size, you must make sure that
1506 this memory test is non-destructive. So far, the
1507 following board configurations are known to be
1510 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1511 HERMES, IP860, RPXlite, LWMON, LANTEC,
1512 PCU_E, FLAGADM, TQM8260
1517 Define this variable to stop the system in case of a
1518 fatal error, so that you have to reset it manually.
1519 This is probably NOT a good idea for an embedded
1520 system where you want to system to reboot
1521 automatically as fast as possible, but it may be
1522 useful during development since you can try to debug
1523 the conditions that lead to the situation.
1525 CONFIG_NET_RETRY_COUNT
1527 This variable defines the number of retries for
1528 network operations like ARP, RARP, TFTP, or BOOTP
1529 before giving up the operation. If not defined, a
1530 default value of 5 is used.
1532 - Command Interpreter:
1533 CONFIG_AUTO_COMPLETE
1535 Enable auto completion of commands using TAB.
1537 Note that this feature has NOT been implemented yet
1538 for the "hush" shell.
1543 Define this variable to enable the "hush" shell (from
1544 Busybox) as command line interpreter, thus enabling
1545 powerful command line syntax like
1546 if...then...else...fi conditionals or `&&' and '||'
1547 constructs ("shell scripts").
1549 If undefined, you get the old, much simpler behaviour
1550 with a somewhat smaller memory footprint.
1555 This defines the secondary prompt string, which is
1556 printed when the command interpreter needs more input
1557 to complete a command. Usually "> ".
1561 In the current implementation, the local variables
1562 space and global environment variables space are
1563 separated. Local variables are those you define by
1564 simply typing `name=value'. To access a local
1565 variable later on, you have write `$name' or
1566 `${name}'; to execute the contents of a variable
1567 directly type `$name' at the command prompt.
1569 Global environment variables are those you use
1570 setenv/printenv to work with. To run a command stored
1571 in such a variable, you need to use the run command,
1572 and you must not use the '$' sign to access them.
1574 To store commands and special characters in a
1575 variable, please use double quotation marks
1576 surrounding the whole text of the variable, instead
1577 of the backslashes before semicolons and special
1580 - Commandline Editing and History:
1581 CONFIG_CMDLINE_EDITING
1583 Enable editiong and History functions for interactive
1584 commandline input operations
1586 - Default Environment:
1587 CONFIG_EXTRA_ENV_SETTINGS
1589 Define this to contain any number of null terminated
1590 strings (variable = value pairs) that will be part of
1591 the default environment compiled into the boot image.
1593 For example, place something like this in your
1594 board's config file:
1596 #define CONFIG_EXTRA_ENV_SETTINGS \
1600 Warning: This method is based on knowledge about the
1601 internal format how the environment is stored by the
1602 U-Boot code. This is NOT an official, exported
1603 interface! Although it is unlikely that this format
1604 will change soon, there is no guarantee either.
1605 You better know what you are doing here.
1607 Note: overly (ab)use of the default environment is
1608 discouraged. Make sure to check other ways to preset
1609 the environment like the autoscript function or the
1612 - DataFlash Support:
1613 CONFIG_HAS_DATAFLASH
1615 Defining this option enables DataFlash features and
1616 allows to read/write in Dataflash via the standard
1619 - SystemACE Support:
1622 Adding this option adds support for Xilinx SystemACE
1623 chips attached via some sort of local bus. The address
1624 of the chip must alsh be defined in the
1625 CFG_SYSTEMACE_BASE macro. For example:
1627 #define CONFIG_SYSTEMACE
1628 #define CFG_SYSTEMACE_BASE 0xf0000000
1630 When SystemACE support is added, the "ace" device type
1631 becomes available to the fat commands, i.e. fatls.
1633 - TFTP Fixed UDP Port:
1636 If this is defined, the environment variable tftpsrcp
1637 is used to supply the TFTP UDP source port value.
1638 If tftpsrcp isn't defined, the normal pseudo-random port
1639 number generator is used.
1641 Also, the environment variable tftpdstp is used to supply
1642 the TFTP UDP destination port value. If tftpdstp isn't
1643 defined, the normal port 69 is used.
1645 The purpose for tftpsrcp is to allow a TFTP server to
1646 blindly start the TFTP transfer using the pre-configured
1647 target IP address and UDP port. This has the effect of
1648 "punching through" the (Windows XP) firewall, allowing
1649 the remainder of the TFTP transfer to proceed normally.
1650 A better solution is to properly configure the firewall,
1651 but sometimes that is not allowed.
1653 - Show boot progress:
1654 CONFIG_SHOW_BOOT_PROGRESS
1656 Defining this option allows to add some board-
1657 specific code (calling a user-provided function
1658 "show_boot_progress(int)") that enables you to show
1659 the system's boot progress on some display (for
1660 example, some LED's) on your board. At the moment,
1661 the following checkpoints are implemented:
1664 1 common/cmd_bootm.c before attempting to boot an image
1665 -1 common/cmd_bootm.c Image header has bad magic number
1666 2 common/cmd_bootm.c Image header has correct magic number
1667 -2 common/cmd_bootm.c Image header has bad checksum
1668 3 common/cmd_bootm.c Image header has correct checksum
1669 -3 common/cmd_bootm.c Image data has bad checksum
1670 4 common/cmd_bootm.c Image data has correct checksum
1671 -4 common/cmd_bootm.c Image is for unsupported architecture
1672 5 common/cmd_bootm.c Architecture check OK
1673 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1674 6 common/cmd_bootm.c Image Type check OK
1675 -6 common/cmd_bootm.c gunzip uncompression error
1676 -7 common/cmd_bootm.c Unimplemented compression type
1677 7 common/cmd_bootm.c Uncompression OK
1678 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1679 8 common/cmd_bootm.c Image Type check OK
1680 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1681 9 common/cmd_bootm.c Start initial ramdisk verification
1682 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1683 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1684 10 common/cmd_bootm.c Ramdisk header is OK
1685 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1686 11 common/cmd_bootm.c Ramdisk data has correct checksum
1687 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1688 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1689 13 common/cmd_bootm.c Start multifile image verification
1690 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1691 15 common/cmd_bootm.c All preparation done, transferring control to OS
1693 -30 lib_ppc/board.c Fatal error, hang the system
1694 -31 post/post.c POST test failed, detected by post_output_backlog()
1695 -32 post/post.c POST test failed, detected by post_run_single()
1697 34 common/cmd_doc.c before loading a Image from a DOC device
1698 -35 common/cmd_doc.c Bad usage of "doc" command
1699 35 common/cmd_doc.c correct usage of "doc" command
1700 -36 common/cmd_doc.c No boot device
1701 36 common/cmd_doc.c correct boot device
1702 -37 common/cmd_doc.c Unknown Chip ID on boot device
1703 37 common/cmd_doc.c correct chip ID found, device available
1704 -38 common/cmd_doc.c Read Error on boot device
1705 38 common/cmd_doc.c reading Image header from DOC device OK
1706 -39 common/cmd_doc.c Image header has bad magic number
1707 39 common/cmd_doc.c Image header has correct magic number
1708 -40 common/cmd_doc.c Error reading Image from DOC device
1709 40 common/cmd_doc.c Image header has correct magic number
1710 41 common/cmd_ide.c before loading a Image from a IDE device
1711 -42 common/cmd_ide.c Bad usage of "ide" command
1712 42 common/cmd_ide.c correct usage of "ide" command
1713 -43 common/cmd_ide.c No boot device
1714 43 common/cmd_ide.c boot device found
1715 -44 common/cmd_ide.c Device not available
1716 44 common/cmd_ide.c Device available
1717 -45 common/cmd_ide.c wrong partition selected
1718 45 common/cmd_ide.c partition selected
1719 -46 common/cmd_ide.c Unknown partition table
1720 46 common/cmd_ide.c valid partition table found
1721 -47 common/cmd_ide.c Invalid partition type
1722 47 common/cmd_ide.c correct partition type
1723 -48 common/cmd_ide.c Error reading Image Header on boot device
1724 48 common/cmd_ide.c reading Image Header from IDE device OK
1725 -49 common/cmd_ide.c Image header has bad magic number
1726 49 common/cmd_ide.c Image header has correct magic number
1727 -50 common/cmd_ide.c Image header has bad checksum
1728 50 common/cmd_ide.c Image header has correct checksum
1729 -51 common/cmd_ide.c Error reading Image from IDE device
1730 51 common/cmd_ide.c reading Image from IDE device OK
1731 52 common/cmd_nand.c before loading a Image from a NAND device
1732 -53 common/cmd_nand.c Bad usage of "nand" command
1733 53 common/cmd_nand.c correct usage of "nand" command
1734 -54 common/cmd_nand.c No boot device
1735 54 common/cmd_nand.c boot device found
1736 -55 common/cmd_nand.c Unknown Chip ID on boot device
1737 55 common/cmd_nand.c correct chip ID found, device available
1738 -56 common/cmd_nand.c Error reading Image Header on boot device
1739 56 common/cmd_nand.c reading Image Header from NAND device OK
1740 -57 common/cmd_nand.c Image header has bad magic number
1741 57 common/cmd_nand.c Image header has correct magic number
1742 -58 common/cmd_nand.c Error reading Image from NAND device
1743 58 common/cmd_nand.c reading Image from NAND device OK
1745 -60 common/env_common.c Environment has a bad CRC, using default
1747 64 net/eth.c starting with Ethernetconfiguration.
1748 -64 net/eth.c no Ethernet found.
1749 65 net/eth.c Ethernet found.
1751 -80 common/cmd_net.c usage wrong
1752 80 common/cmd_net.c before calling NetLoop()
1753 -81 common/cmd_net.c some error in NetLoop() occured
1754 81 common/cmd_net.c NetLoop() back without error
1755 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1756 82 common/cmd_net.c trying automatic boot
1757 83 common/cmd_net.c running autoscript
1758 -83 common/cmd_net.c some error in automatic boot or autoscript
1759 84 common/cmd_net.c end without errors
1764 [so far only for SMDK2400 and TRAB boards]
1766 - Modem support endable:
1767 CONFIG_MODEM_SUPPORT
1769 - RTS/CTS Flow control enable:
1772 - Modem debug support:
1773 CONFIG_MODEM_SUPPORT_DEBUG
1775 Enables debugging stuff (char screen[1024], dbg())
1776 for modem support. Useful only with BDI2000.
1778 - Interrupt support (PPC):
1780 There are common interrupt_init() and timer_interrupt()
1781 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1782 for cpu specific initialization. interrupt_init_cpu()
1783 should set decrementer_count to appropriate value. If
1784 cpu resets decrementer automatically after interrupt
1785 (ppc4xx) it should set decrementer_count to zero.
1786 timer_interrupt() calls timer_interrupt_cpu() for cpu
1787 specific handling. If board has watchdog / status_led
1788 / other_activity_monitor it works automatically from
1789 general timer_interrupt().
1793 In the target system modem support is enabled when a
1794 specific key (key combination) is pressed during
1795 power-on. Otherwise U-Boot will boot normally
1796 (autoboot). The key_pressed() fuction is called from
1797 board_init(). Currently key_pressed() is a dummy
1798 function, returning 1 and thus enabling modem
1801 If there are no modem init strings in the
1802 environment, U-Boot proceed to autoboot; the
1803 previous output (banner, info printfs) will be
1806 See also: doc/README.Modem
1809 Configuration Settings:
1810 -----------------------
1812 - CFG_LONGHELP: Defined when you want long help messages included;
1813 undefine this when you're short of memory.
1815 - CFG_PROMPT: This is what U-Boot prints on the console to
1816 prompt for user input.
1818 - CFG_CBSIZE: Buffer size for input from the Console
1820 - CFG_PBSIZE: Buffer size for Console output
1822 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1824 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1825 the application (usually a Linux kernel) when it is
1828 - CFG_BAUDRATE_TABLE:
1829 List of legal baudrate settings for this board.
1831 - CFG_CONSOLE_INFO_QUIET
1832 Suppress display of console information at boot.
1834 - CFG_CONSOLE_IS_IN_ENV
1835 If the board specific function
1836 extern int overwrite_console (void);
1837 returns 1, the stdin, stderr and stdout are switched to the
1838 serial port, else the settings in the environment are used.
1840 - CFG_CONSOLE_OVERWRITE_ROUTINE
1841 Enable the call to overwrite_console().
1843 - CFG_CONSOLE_ENV_OVERWRITE
1844 Enable overwrite of previous console environment settings.
1846 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1847 Begin and End addresses of the area used by the
1851 Enable an alternate, more extensive memory test.
1853 - CFG_MEMTEST_SCRATCH:
1854 Scratch address used by the alternate memory test
1855 You only need to set this if address zero isn't writeable
1857 - CFG_TFTP_LOADADDR:
1858 Default load address for network file downloads
1860 - CFG_LOADS_BAUD_CHANGE:
1861 Enable temporary baudrate change while serial download
1864 Physical start address of SDRAM. _Must_ be 0 here.
1867 Physical start address of Motherboard I/O (if using a
1871 Physical start address of Flash memory.
1874 Physical start address of boot monitor code (set by
1875 make config files to be same as the text base address
1876 (TEXT_BASE) used when linking) - same as
1877 CFG_FLASH_BASE when booting from flash.
1880 Size of memory reserved for monitor code, used to
1881 determine _at_compile_time_ (!) if the environment is
1882 embedded within the U-Boot image, or in a separate
1886 Size of DRAM reserved for malloc() use.
1889 Normally compressed uImages are limited to an
1890 uncompressed size of 8 MBytes. If this is not enough,
1891 you can define CFG_BOOTM_LEN in your board config file
1892 to adjust this setting to your needs.
1895 Maximum size of memory mapped by the startup code of
1896 the Linux kernel; all data that must be processed by
1897 the Linux kernel (bd_info, boot arguments, eventually
1898 initrd image) must be put below this limit.
1900 - CFG_MAX_FLASH_BANKS:
1901 Max number of Flash memory banks
1903 - CFG_MAX_FLASH_SECT:
1904 Max number of sectors on a Flash chip
1906 - CFG_FLASH_ERASE_TOUT:
1907 Timeout for Flash erase operations (in ms)
1909 - CFG_FLASH_WRITE_TOUT:
1910 Timeout for Flash write operations (in ms)
1912 - CFG_FLASH_LOCK_TOUT
1913 Timeout for Flash set sector lock bit operation (in ms)
1915 - CFG_FLASH_UNLOCK_TOUT
1916 Timeout for Flash clear lock bits operation (in ms)
1918 - CFG_FLASH_PROTECTION
1919 If defined, hardware flash sectors protection is used
1920 instead of U-Boot software protection.
1922 - CFG_DIRECT_FLASH_TFTP:
1924 Enable TFTP transfers directly to flash memory;
1925 without this option such a download has to be
1926 performed in two steps: (1) download to RAM, and (2)
1927 copy from RAM to flash.
1929 The two-step approach is usually more reliable, since
1930 you can check if the download worked before you erase
1931 the flash, but in some situations (when sytem RAM is
1932 too limited to allow for a tempory copy of the
1933 downloaded image) this option may be very useful.
1936 Define if the flash driver uses extra elements in the
1937 common flash structure for storing flash geometry.
1939 - CFG_FLASH_CFI_DRIVER
1940 This option also enables the building of the cfi_flash driver
1941 in the drivers directory
1943 - CFG_FLASH_QUIET_TEST
1944 If this option is defined, the common CFI flash doesn't
1945 print it's warning upon not recognized FLASH banks. This
1946 is useful, if some of the configured banks are only
1947 optionally available.
1949 - CFG_RX_ETH_BUFFER:
1950 Defines the number of ethernet receive buffers. On some
1951 ethernet controllers it is recommended to set this value
1952 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1953 buffers can be full shortly after enabling the interface
1954 on high ethernet traffic.
1955 Defaults to 4 if not defined.
1957 The following definitions that deal with the placement and management
1958 of environment data (variable area); in general, we support the
1959 following configurations:
1961 - CFG_ENV_IS_IN_FLASH:
1963 Define this if the environment is in flash memory.
1965 a) The environment occupies one whole flash sector, which is
1966 "embedded" in the text segment with the U-Boot code. This
1967 happens usually with "bottom boot sector" or "top boot
1968 sector" type flash chips, which have several smaller
1969 sectors at the start or the end. For instance, such a
1970 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1971 such a case you would place the environment in one of the
1972 4 kB sectors - with U-Boot code before and after it. With
1973 "top boot sector" type flash chips, you would put the
1974 environment in one of the last sectors, leaving a gap
1975 between U-Boot and the environment.
1979 Offset of environment data (variable area) to the
1980 beginning of flash memory; for instance, with bottom boot
1981 type flash chips the second sector can be used: the offset
1982 for this sector is given here.
1984 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1988 This is just another way to specify the start address of
1989 the flash sector containing the environment (instead of
1992 - CFG_ENV_SECT_SIZE:
1994 Size of the sector containing the environment.
1997 b) Sometimes flash chips have few, equal sized, BIG sectors.
1998 In such a case you don't want to spend a whole sector for
2003 If you use this in combination with CFG_ENV_IS_IN_FLASH
2004 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2005 of this flash sector for the environment. This saves
2006 memory for the RAM copy of the environment.
2008 It may also save flash memory if you decide to use this
2009 when your environment is "embedded" within U-Boot code,
2010 since then the remainder of the flash sector could be used
2011 for U-Boot code. It should be pointed out that this is
2012 STRONGLY DISCOURAGED from a robustness point of view:
2013 updating the environment in flash makes it always
2014 necessary to erase the WHOLE sector. If something goes
2015 wrong before the contents has been restored from a copy in
2016 RAM, your target system will be dead.
2018 - CFG_ENV_ADDR_REDUND
2021 These settings describe a second storage area used to hold
2022 a redundand copy of the environment data, so that there is
2023 a valid backup copy in case there is a power failure during
2024 a "saveenv" operation.
2026 BE CAREFUL! Any changes to the flash layout, and some changes to the
2027 source code will make it necessary to adapt <board>/u-boot.lds*
2031 - CFG_ENV_IS_IN_NVRAM:
2033 Define this if you have some non-volatile memory device
2034 (NVRAM, battery buffered SRAM) which you want to use for the
2040 These two #defines are used to determin the memory area you
2041 want to use for environment. It is assumed that this memory
2042 can just be read and written to, without any special
2045 BE CAREFUL! The first access to the environment happens quite early
2046 in U-Boot initalization (when we try to get the setting of for the
2047 console baudrate). You *MUST* have mappend your NVRAM area then, or
2050 Please note that even with NVRAM we still use a copy of the
2051 environment in RAM: we could work on NVRAM directly, but we want to
2052 keep settings there always unmodified except somebody uses "saveenv"
2053 to save the current settings.
2056 - CFG_ENV_IS_IN_EEPROM:
2058 Use this if you have an EEPROM or similar serial access
2059 device and a driver for it.
2064 These two #defines specify the offset and size of the
2065 environment area within the total memory of your EEPROM.
2067 - CFG_I2C_EEPROM_ADDR:
2068 If defined, specified the chip address of the EEPROM device.
2069 The default address is zero.
2071 - CFG_EEPROM_PAGE_WRITE_BITS:
2072 If defined, the number of bits used to address bytes in a
2073 single page in the EEPROM device. A 64 byte page, for example
2074 would require six bits.
2076 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2077 If defined, the number of milliseconds to delay between
2078 page writes. The default is zero milliseconds.
2080 - CFG_I2C_EEPROM_ADDR_LEN:
2081 The length in bytes of the EEPROM memory array address. Note
2082 that this is NOT the chip address length!
2084 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2085 EEPROM chips that implement "address overflow" are ones
2086 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2087 address and the extra bits end up in the "chip address" bit
2088 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2091 Note that we consider the length of the address field to
2092 still be one byte because the extra address bits are hidden
2093 in the chip address.
2096 The size in bytes of the EEPROM device.
2099 - CFG_ENV_IS_IN_DATAFLASH:
2101 Define this if you have a DataFlash memory device which you
2102 want to use for the environment.
2108 These three #defines specify the offset and size of the
2109 environment area within the total memory of your DataFlash placed
2110 at the specified address.
2112 - CFG_ENV_IS_IN_NAND:
2114 Define this if you have a NAND device which you want to use
2115 for the environment.
2120 These two #defines specify the offset and size of the environment
2121 area within the first NAND device.
2123 - CFG_ENV_OFFSET_REDUND
2125 This setting describes a second storage area of CFG_ENV_SIZE
2126 size used to hold a redundant copy of the environment data,
2127 so that there is a valid backup copy in case there is a
2128 power failure during a "saveenv" operation.
2130 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2131 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2132 the NAND devices block size.
2134 - CFG_SPI_INIT_OFFSET
2136 Defines offset to the initial SPI buffer area in DPRAM. The
2137 area is used at an early stage (ROM part) if the environment
2138 is configured to reside in the SPI EEPROM: We need a 520 byte
2139 scratch DPRAM area. It is used between the two initialization
2140 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2141 to be a good choice since it makes it far enough from the
2142 start of the data area as well as from the stack pointer.
2144 Please note that the environment is read-only until the monitor
2145 has been relocated to RAM and a RAM copy of the environment has been
2146 created; also, when using EEPROM you will have to use getenv_r()
2147 until then to read environment variables.
2149 The environment is protected by a CRC32 checksum. Before the monitor
2150 is relocated into RAM, as a result of a bad CRC you will be working
2151 with the compiled-in default environment - *silently*!!! [This is
2152 necessary, because the first environment variable we need is the
2153 "baudrate" setting for the console - if we have a bad CRC, we don't
2154 have any device yet where we could complain.]
2156 Note: once the monitor has been relocated, then it will complain if
2157 the default environment is used; a new CRC is computed as soon as you
2158 use the "saveenv" command to store a valid environment.
2160 - CFG_FAULT_ECHO_LINK_DOWN:
2161 Echo the inverted Ethernet link state to the fault LED.
2163 Note: If this option is active, then CFG_FAULT_MII_ADDR
2164 also needs to be defined.
2166 - CFG_FAULT_MII_ADDR:
2167 MII address of the PHY to check for the Ethernet link state.
2169 - CFG_64BIT_VSPRINTF:
2170 Makes vsprintf (and all *printf functions) support printing
2171 of 64bit values by using the L quantifier
2173 - CFG_64BIT_STRTOUL:
2174 Adds simple_strtoull that returns a 64bit value
2176 Low Level (hardware related) configuration options:
2177 ---------------------------------------------------
2179 - CFG_CACHELINE_SIZE:
2180 Cache Line Size of the CPU.
2183 Default address of the IMMR after system reset.
2185 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2186 and RPXsuper) to be able to adjust the position of
2187 the IMMR register after a reset.
2189 - Floppy Disk Support:
2190 CFG_FDC_DRIVE_NUMBER
2192 the default drive number (default value 0)
2196 defines the spacing between fdc chipset registers
2201 defines the offset of register from address. It
2202 depends on which part of the data bus is connected to
2203 the fdc chipset. (default value 0)
2205 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2206 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2209 if CFG_FDC_HW_INIT is defined, then the function
2210 fdc_hw_init() is called at the beginning of the FDC
2211 setup. fdc_hw_init() must be provided by the board
2212 source code. It is used to make hardware dependant
2215 - CFG_IMMR: Physical address of the Internal Memory.
2216 DO NOT CHANGE unless you know exactly what you're
2217 doing! (11-4) [MPC8xx/82xx systems only]
2219 - CFG_INIT_RAM_ADDR:
2221 Start address of memory area that can be used for
2222 initial data and stack; please note that this must be
2223 writable memory that is working WITHOUT special
2224 initialization, i. e. you CANNOT use normal RAM which
2225 will become available only after programming the
2226 memory controller and running certain initialization
2229 U-Boot uses the following memory types:
2230 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2231 - MPC824X: data cache
2232 - PPC4xx: data cache
2234 - CFG_GBL_DATA_OFFSET:
2236 Offset of the initial data structure in the memory
2237 area defined by CFG_INIT_RAM_ADDR. Usually
2238 CFG_GBL_DATA_OFFSET is chosen such that the initial
2239 data is located at the end of the available space
2240 (sometimes written as (CFG_INIT_RAM_END -
2241 CFG_INIT_DATA_SIZE), and the initial stack is just
2242 below that area (growing from (CFG_INIT_RAM_ADDR +
2243 CFG_GBL_DATA_OFFSET) downward.
2246 On the MPC824X (or other systems that use the data
2247 cache for initial memory) the address chosen for
2248 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2249 point to an otherwise UNUSED address space between
2250 the top of RAM and the start of the PCI space.
2252 - CFG_SIUMCR: SIU Module Configuration (11-6)
2254 - CFG_SYPCR: System Protection Control (11-9)
2256 - CFG_TBSCR: Time Base Status and Control (11-26)
2258 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2260 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2262 - CFG_SCCR: System Clock and reset Control Register (15-27)
2264 - CFG_OR_TIMING_SDRAM:
2268 periodic timer for refresh
2270 - CFG_DER: Debug Event Register (37-47)
2272 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2273 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2274 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2276 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2278 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2279 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2280 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2281 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2283 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2284 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2285 Machine Mode Register and Memory Periodic Timer
2286 Prescaler definitions (SDRAM timing)
2288 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2289 enable I2C microcode relocation patch (MPC8xx);
2290 define relocation offset in DPRAM [DSP2]
2292 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2293 enable SMC microcode relocation patch (MPC8xx);
2294 define relocation offset in DPRAM [SMC1]
2296 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2297 enable SPI microcode relocation patch (MPC8xx);
2298 define relocation offset in DPRAM [SCC4]
2301 Use OSCM clock mode on MBX8xx board. Be careful,
2302 wrong setting might damage your board. Read
2303 doc/README.MBX before setting this variable!
2305 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2306 Offset of the bootmode word in DPRAM used by post
2307 (Power On Self Tests). This definition overrides
2308 #define'd default value in commproc.h resp.
2311 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2312 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2313 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2314 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2315 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2316 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2317 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2318 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2319 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2322 Get DDR timing information from an I2C EEPROM. Common with pluggable
2323 memory modules such as SODIMMs
2325 I2C address of the SPD EEPROM
2328 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2329 Note that the value must resolve to something your driver can deal with.
2331 - CFG_83XX_DDR_USES_CS0
2332 Only for 83xx systems. If specified, then DDR should be configured
2333 using CS0 and CS1 instead of CS2 and CS3.
2335 - CFG_83XX_DDR_USES_CS0
2336 Only for 83xx systems. If specified, then DDR should be configured
2337 using CS0 and CS1 instead of CS2 and CS3.
2339 - CONFIG_ETHER_ON_FEC[12]
2340 Define to enable FEC[12] on a 8xx series processor.
2342 - CONFIG_FEC[12]_PHY
2343 Define to the hardcoded PHY address which corresponds
2344 to the given FEC; i. e.
2345 #define CONFIG_FEC1_PHY 4
2346 means that the PHY with address 4 is connected to FEC1
2348 When set to -1, means to probe for first available.
2350 - CONFIG_FEC[12]_PHY_NORXERR
2351 The PHY does not have a RXERR line (RMII only).
2352 (so program the FEC to ignore it).
2355 Enable RMII mode for all FECs.
2356 Note that this is a global option, we can't
2357 have one FEC in standard MII mode and another in RMII mode.
2359 - CONFIG_CRC32_VERIFY
2360 Add a verify option to the crc32 command.
2363 => crc32 -v <address> <count> <crc32>
2365 Where address/count indicate a memory area
2366 and crc32 is the correct crc32 which the
2370 Add the "loopw" memory command. This only takes effect if
2371 the memory commands are activated globally (CONFIG_CMD_MEM).
2374 Add the "mdc" and "mwc" memory commands. These are cyclic
2379 This command will print 4 bytes (10,11,12,13) each 500 ms.
2381 => mwc.l 100 12345678 10
2382 This command will write 12345678 to address 100 all 10 ms.
2384 This only takes effect if the memory commands are activated
2385 globally (CONFIG_CMD_MEM).
2387 - CONFIG_SKIP_LOWLEVEL_INIT
2388 - CONFIG_SKIP_RELOCATE_UBOOT
2390 [ARM only] If these variables are defined, then
2391 certain low level initializations (like setting up
2392 the memory controller) are omitted and/or U-Boot does
2393 not relocate itself into RAM.
2394 Normally these variables MUST NOT be defined. The
2395 only exception is when U-Boot is loaded (to RAM) by
2396 some other boot loader or by a debugger which
2397 performs these intializations itself.
2400 Building the Software:
2401 ======================
2403 Building U-Boot has been tested in native PPC environments (on a
2404 PowerBook G3 running LinuxPPC 2000) and in cross environments
2405 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2408 If you are not using a native PPC environment, it is assumed that you
2409 have the GNU cross compiling tools available in your path and named
2410 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2411 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2412 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2415 CROSS_COMPILE = ppc_4xx-
2418 U-Boot is intended to be simple to build. After installing the
2419 sources you must configure U-Boot for one specific board type. This
2424 where "NAME_config" is the name of one of the existing
2425 configurations; see the main Makefile for supported names.
2427 Note: for some board special configuration names may exist; check if
2428 additional information is available from the board vendor; for
2429 instance, the TQM823L systems are available without (standard)
2430 or with LCD support. You can select such additional "features"
2431 when chosing the configuration, i. e.
2434 - will configure for a plain TQM823L, i. e. no LCD support
2436 make TQM823L_LCD_config
2437 - will configure for a TQM823L with U-Boot console on LCD
2442 Finally, type "make all", and you should get some working U-Boot
2443 images ready for download to / installation on your system:
2445 - "u-boot.bin" is a raw binary image
2446 - "u-boot" is an image in ELF binary format
2447 - "u-boot.srec" is in Motorola S-Record format
2449 By default the build is performed locally and the objects are saved
2450 in the source directory. One of the two methods can be used to change
2451 this behavior and build U-Boot to some external directory:
2453 1. Add O= to the make command line invocations:
2455 make O=/tmp/build distclean
2456 make O=/tmp/build NAME_config
2457 make O=/tmp/build all
2459 2. Set environment variable BUILD_DIR to point to the desired location:
2461 export BUILD_DIR=/tmp/build
2466 Note that the command line "O=" setting overrides the BUILD_DIR environment
2470 Please be aware that the Makefiles assume you are using GNU make, so
2471 for instance on NetBSD you might need to use "gmake" instead of
2475 If the system board that you have is not listed, then you will need
2476 to port U-Boot to your hardware platform. To do this, follow these
2479 1. Add a new configuration option for your board to the toplevel
2480 "Makefile" and to the "MAKEALL" script, using the existing
2481 entries as examples. Note that here and at many other places
2482 boards and other names are listed in alphabetical sort order. Please
2484 2. Create a new directory to hold your board specific code. Add any
2485 files you need. In your board directory, you will need at least
2486 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2487 3. Create a new configuration file "include/configs/<board>.h" for
2489 3. If you're porting U-Boot to a new CPU, then also create a new
2490 directory to hold your CPU specific code. Add any files you need.
2491 4. Run "make <board>_config" with your new name.
2492 5. Type "make", and you should get a working "u-boot.srec" file
2493 to be installed on your target system.
2494 6. Debug and solve any problems that might arise.
2495 [Of course, this last step is much harder than it sounds.]
2498 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2499 ==============================================================
2501 If you have modified U-Boot sources (for instance added a new board
2502 or support for new devices, a new CPU, etc.) you are expected to
2503 provide feedback to the other developers. The feedback normally takes
2504 the form of a "patch", i. e. a context diff against a certain (latest
2505 official or latest in CVS) version of U-Boot sources.
2507 But before you submit such a patch, please verify that your modifi-
2508 cation did not break existing code. At least make sure that *ALL* of
2509 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2510 just run the "MAKEALL" script, which will configure and build U-Boot
2511 for ALL supported system. Be warned, this will take a while. You can
2512 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2513 environment variable to the script, i. e. to use the cross tools from
2514 MontaVista's Hard Hat Linux you can type
2516 CROSS_COMPILE=ppc_8xx- MAKEALL
2518 or to build on a native PowerPC system you can type
2520 CROSS_COMPILE=' ' MAKEALL
2522 When using the MAKEALL script, the default behaviour is to build U-Boot
2523 in the source directory. This location can be changed by setting the
2524 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2525 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2526 <source dir>/LOG directory. This default location can be changed by
2527 setting the MAKEALL_LOGDIR environment variable. For example:
2529 export BUILD_DIR=/tmp/build
2530 export MAKEALL_LOGDIR=/tmp/log
2531 CROSS_COMPILE=ppc_8xx- MAKEALL
2533 With the above settings build objects are saved in the /tmp/build, log
2534 files are saved in the /tmp/log and the source tree remains clean during
2535 the whole build process.
2538 See also "U-Boot Porting Guide" below.
2541 Monitor Commands - Overview:
2542 ============================
2544 go - start application at address 'addr'
2545 run - run commands in an environment variable
2546 bootm - boot application image from memory
2547 bootp - boot image via network using BootP/TFTP protocol
2548 tftpboot- boot image via network using TFTP protocol
2549 and env variables "ipaddr" and "serverip"
2550 (and eventually "gatewayip")
2551 rarpboot- boot image via network using RARP/TFTP protocol
2552 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2553 loads - load S-Record file over serial line
2554 loadb - load binary file over serial line (kermit mode)
2556 mm - memory modify (auto-incrementing)
2557 nm - memory modify (constant address)
2558 mw - memory write (fill)
2560 cmp - memory compare
2561 crc32 - checksum calculation
2562 imd - i2c memory display
2563 imm - i2c memory modify (auto-incrementing)
2564 inm - i2c memory modify (constant address)
2565 imw - i2c memory write (fill)
2566 icrc32 - i2c checksum calculation
2567 iprobe - probe to discover valid I2C chip addresses
2568 iloop - infinite loop on address range
2569 isdram - print SDRAM configuration information
2570 sspi - SPI utility commands
2571 base - print or set address offset
2572 printenv- print environment variables
2573 setenv - set environment variables
2574 saveenv - save environment variables to persistent storage
2575 protect - enable or disable FLASH write protection
2576 erase - erase FLASH memory
2577 flinfo - print FLASH memory information
2578 bdinfo - print Board Info structure
2579 iminfo - print header information for application image
2580 coninfo - print console devices and informations
2581 ide - IDE sub-system
2582 loop - infinite loop on address range
2583 loopw - infinite write loop on address range
2584 mtest - simple RAM test
2585 icache - enable or disable instruction cache
2586 dcache - enable or disable data cache
2587 reset - Perform RESET of the CPU
2588 echo - echo args to console
2589 version - print monitor version
2590 help - print online help
2591 ? - alias for 'help'
2594 Monitor Commands - Detailed Description:
2595 ========================================
2599 For now: just type "help <command>".
2602 Environment Variables:
2603 ======================
2605 U-Boot supports user configuration using Environment Variables which
2606 can be made persistent by saving to Flash memory.
2608 Environment Variables are set using "setenv", printed using
2609 "printenv", and saved to Flash using "saveenv". Using "setenv"
2610 without a value can be used to delete a variable from the
2611 environment. As long as you don't save the environment you are
2612 working with an in-memory copy. In case the Flash area containing the
2613 environment is erased by accident, a default environment is provided.
2615 Some configuration options can be set using Environment Variables:
2617 baudrate - see CONFIG_BAUDRATE
2619 bootdelay - see CONFIG_BOOTDELAY
2621 bootcmd - see CONFIG_BOOTCOMMAND
2623 bootargs - Boot arguments when booting an RTOS image
2625 bootfile - Name of the image to load with TFTP
2627 autoload - if set to "no" (any string beginning with 'n'),
2628 "bootp" will just load perform a lookup of the
2629 configuration from the BOOTP server, but not try to
2630 load any image using TFTP
2632 autostart - if set to "yes", an image loaded using the "bootp",
2633 "rarpboot", "tftpboot" or "diskboot" commands will
2634 be automatically started (by internally calling
2637 If set to "no", a standalone image passed to the
2638 "bootm" command will be copied to the load address
2639 (and eventually uncompressed), but NOT be started.
2640 This can be used to load and uncompress arbitrary
2643 i2cfast - (PPC405GP|PPC405EP only)
2644 if set to 'y' configures Linux I2C driver for fast
2645 mode (400kHZ). This environment variable is used in
2646 initialization code. So, for changes to be effective
2647 it must be saved and board must be reset.
2649 initrd_high - restrict positioning of initrd images:
2650 If this variable is not set, initrd images will be
2651 copied to the highest possible address in RAM; this
2652 is usually what you want since it allows for
2653 maximum initrd size. If for some reason you want to
2654 make sure that the initrd image is loaded below the
2655 CFG_BOOTMAPSZ limit, you can set this environment
2656 variable to a value of "no" or "off" or "0".
2657 Alternatively, you can set it to a maximum upper
2658 address to use (U-Boot will still check that it
2659 does not overwrite the U-Boot stack and data).
2661 For instance, when you have a system with 16 MB
2662 RAM, and want to reserve 4 MB from use by Linux,
2663 you can do this by adding "mem=12M" to the value of
2664 the "bootargs" variable. However, now you must make
2665 sure that the initrd image is placed in the first
2666 12 MB as well - this can be done with
2668 setenv initrd_high 00c00000
2670 If you set initrd_high to 0xFFFFFFFF, this is an
2671 indication to U-Boot that all addresses are legal
2672 for the Linux kernel, including addresses in flash
2673 memory. In this case U-Boot will NOT COPY the
2674 ramdisk at all. This may be useful to reduce the
2675 boot time on your system, but requires that this
2676 feature is supported by your Linux kernel.
2678 ipaddr - IP address; needed for tftpboot command
2680 loadaddr - Default load address for commands like "bootp",
2681 "rarpboot", "tftpboot", "loadb" or "diskboot"
2683 loads_echo - see CONFIG_LOADS_ECHO
2685 serverip - TFTP server IP address; needed for tftpboot command
2687 bootretry - see CONFIG_BOOT_RETRY_TIME
2689 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2691 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2693 ethprime - When CONFIG_NET_MULTI is enabled controls which
2694 interface is used first.
2696 ethact - When CONFIG_NET_MULTI is enabled controls which
2697 interface is currently active. For example you
2698 can do the following
2700 => setenv ethact FEC ETHERNET
2701 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2702 => setenv ethact SCC ETHERNET
2703 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2705 ethrotate - When set to "no" U-Boot does not go through all
2706 available network interfaces.
2707 It just stays at the currently selected interface.
2709 netretry - When set to "no" each network operation will
2710 either succeed or fail without retrying.
2711 When set to "once" the network operation will
2712 fail when all the available network interfaces
2713 are tried once without success.
2714 Useful on scripts which control the retry operation
2717 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2718 if set load address for the npe microcode
2720 tftpsrcport - If this is set, the value is used for TFTP's
2723 tftpdstport - If this is set, the value is used for TFTP's UDP
2724 destination port instead of the Well Know Port 69.
2726 vlan - When set to a value < 4095 the traffic over
2727 ethernet is encapsulated/received over 802.1q
2730 The following environment variables may be used and automatically
2731 updated by the network boot commands ("bootp" and "rarpboot"),
2732 depending the information provided by your boot server:
2734 bootfile - see above
2735 dnsip - IP address of your Domain Name Server
2736 dnsip2 - IP address of your secondary Domain Name Server
2737 gatewayip - IP address of the Gateway (Router) to use
2738 hostname - Target hostname
2740 netmask - Subnet Mask
2741 rootpath - Pathname of the root filesystem on the NFS server
2742 serverip - see above
2745 There are two special Environment Variables:
2747 serial# - contains hardware identification information such
2748 as type string and/or serial number
2749 ethaddr - Ethernet address
2751 These variables can be set only once (usually during manufacturing of
2752 the board). U-Boot refuses to delete or overwrite these variables
2753 once they have been set once.
2756 Further special Environment Variables:
2758 ver - Contains the U-Boot version string as printed
2759 with the "version" command. This variable is
2760 readonly (see CONFIG_VERSION_VARIABLE).
2763 Please note that changes to some configuration parameters may take
2764 only effect after the next boot (yes, that's just like Windoze :-).
2767 Command Line Parsing:
2768 =====================
2770 There are two different command line parsers available with U-Boot:
2771 the old "simple" one, and the much more powerful "hush" shell:
2773 Old, simple command line parser:
2774 --------------------------------
2776 - supports environment variables (through setenv / saveenv commands)
2777 - several commands on one line, separated by ';'
2778 - variable substitution using "... ${name} ..." syntax
2779 - special characters ('$', ';') can be escaped by prefixing with '\',
2781 setenv bootcmd bootm \${address}
2782 - You can also escape text by enclosing in single apostrophes, for example:
2783 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2788 - similar to Bourne shell, with control structures like
2789 if...then...else...fi, for...do...done; while...do...done,
2790 until...do...done, ...
2791 - supports environment ("global") variables (through setenv / saveenv
2792 commands) and local shell variables (through standard shell syntax
2793 "name=value"); only environment variables can be used with "run"
2799 (1) If a command line (or an environment variable executed by a "run"
2800 command) contains several commands separated by semicolon, and
2801 one of these commands fails, then the remaining commands will be
2804 (2) If you execute several variables with one call to run (i. e.
2805 calling run with a list af variables as arguments), any failing
2806 command will cause "run" to terminate, i. e. the remaining
2807 variables are not executed.
2809 Note for Redundant Ethernet Interfaces:
2810 =======================================
2812 Some boards come with redundant ethernet interfaces; U-Boot supports
2813 such configurations and is capable of automatic selection of a
2814 "working" interface when needed. MAC assignment works as follows:
2816 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2817 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2818 "eth1addr" (=>eth1), "eth2addr", ...
2820 If the network interface stores some valid MAC address (for instance
2821 in SROM), this is used as default address if there is NO correspon-
2822 ding setting in the environment; if the corresponding environment
2823 variable is set, this overrides the settings in the card; that means:
2825 o If the SROM has a valid MAC address, and there is no address in the
2826 environment, the SROM's address is used.
2828 o If there is no valid address in the SROM, and a definition in the
2829 environment exists, then the value from the environment variable is
2832 o If both the SROM and the environment contain a MAC address, and
2833 both addresses are the same, this MAC address is used.
2835 o If both the SROM and the environment contain a MAC address, and the
2836 addresses differ, the value from the environment is used and a
2839 o If neither SROM nor the environment contain a MAC address, an error
2846 The "boot" commands of this monitor operate on "image" files which
2847 can be basicly anything, preceeded by a special header; see the
2848 definitions in include/image.h for details; basicly, the header
2849 defines the following image properties:
2851 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2852 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2853 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2854 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2855 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2856 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2857 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2858 * Compression Type (uncompressed, gzip, bzip2)
2864 The header is marked by a special Magic Number, and both the header
2865 and the data portions of the image are secured against corruption by
2872 Although U-Boot should support any OS or standalone application
2873 easily, the main focus has always been on Linux during the design of
2876 U-Boot includes many features that so far have been part of some
2877 special "boot loader" code within the Linux kernel. Also, any
2878 "initrd" images to be used are no longer part of one big Linux image;
2879 instead, kernel and "initrd" are separate images. This implementation
2880 serves several purposes:
2882 - the same features can be used for other OS or standalone
2883 applications (for instance: using compressed images to reduce the
2884 Flash memory footprint)
2886 - it becomes much easier to port new Linux kernel versions because
2887 lots of low-level, hardware dependent stuff are done by U-Boot
2889 - the same Linux kernel image can now be used with different "initrd"
2890 images; of course this also means that different kernel images can
2891 be run with the same "initrd". This makes testing easier (you don't
2892 have to build a new "zImage.initrd" Linux image when you just
2893 change a file in your "initrd"). Also, a field-upgrade of the
2894 software is easier now.
2900 Porting Linux to U-Boot based systems:
2901 ---------------------------------------
2903 U-Boot cannot save you from doing all the necessary modifications to
2904 configure the Linux device drivers for use with your target hardware
2905 (no, we don't intend to provide a full virtual machine interface to
2908 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2910 Just make sure your machine specific header file (for instance
2911 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2912 Information structure as we define in include/u-boot.h, and make
2913 sure that your definition of IMAP_ADDR uses the same value as your
2914 U-Boot configuration in CFG_IMMR.
2917 Configuring the Linux kernel:
2918 -----------------------------
2920 No specific requirements for U-Boot. Make sure you have some root
2921 device (initial ramdisk, NFS) for your target system.
2924 Building a Linux Image:
2925 -----------------------
2927 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2928 not used. If you use recent kernel source, a new build target
2929 "uImage" will exist which automatically builds an image usable by
2930 U-Boot. Most older kernels also have support for a "pImage" target,
2931 which was introduced for our predecessor project PPCBoot and uses a
2932 100% compatible format.
2941 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2942 encapsulate a compressed Linux kernel image with header information,
2943 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2945 * build a standard "vmlinux" kernel image (in ELF binary format):
2947 * convert the kernel into a raw binary image:
2949 ${CROSS_COMPILE}-objcopy -O binary \
2950 -R .note -R .comment \
2951 -S vmlinux linux.bin
2953 * compress the binary image:
2957 * package compressed binary image for U-Boot:
2959 mkimage -A ppc -O linux -T kernel -C gzip \
2960 -a 0 -e 0 -n "Linux Kernel Image" \
2961 -d linux.bin.gz uImage
2964 The "mkimage" tool can also be used to create ramdisk images for use
2965 with U-Boot, either separated from the Linux kernel image, or
2966 combined into one file. "mkimage" encapsulates the images with a 64
2967 byte header containing information about target architecture,
2968 operating system, image type, compression method, entry points, time
2969 stamp, CRC32 checksums, etc.
2971 "mkimage" can be called in two ways: to verify existing images and
2972 print the header information, or to build new images.
2974 In the first form (with "-l" option) mkimage lists the information
2975 contained in the header of an existing U-Boot image; this includes
2976 checksum verification:
2978 tools/mkimage -l image
2979 -l ==> list image header information
2981 The second form (with "-d" option) is used to build a U-Boot image
2982 from a "data file" which is used as image payload:
2984 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2985 -n name -d data_file image
2986 -A ==> set architecture to 'arch'
2987 -O ==> set operating system to 'os'
2988 -T ==> set image type to 'type'
2989 -C ==> set compression type 'comp'
2990 -a ==> set load address to 'addr' (hex)
2991 -e ==> set entry point to 'ep' (hex)
2992 -n ==> set image name to 'name'
2993 -d ==> use image data from 'datafile'
2995 Right now, all Linux kernels for PowerPC systems use the same load
2996 address (0x00000000), but the entry point address depends on the
2999 - 2.2.x kernels have the entry point at 0x0000000C,
3000 - 2.3.x and later kernels have the entry point at 0x00000000.
3002 So a typical call to build a U-Boot image would read:
3004 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3005 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3006 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3007 > examples/uImage.TQM850L
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 (gzip compressed)
3011 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3012 Load Address: 0x00000000
3013 Entry Point: 0x00000000
3015 To verify the contents of the image (or check for corruption):
3017 -> tools/mkimage -l examples/uImage.TQM850L
3018 Image Name: 2.4.4 kernel for TQM850L
3019 Created: Wed Jul 19 02:34:59 2000
3020 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3021 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3022 Load Address: 0x00000000
3023 Entry Point: 0x00000000
3025 NOTE: for embedded systems where boot time is critical you can trade
3026 speed for memory and install an UNCOMPRESSED image instead: this
3027 needs more space in Flash, but boots much faster since it does not
3028 need to be uncompressed:
3030 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3031 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3032 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3033 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3034 > examples/uImage.TQM850L-uncompressed
3035 Image Name: 2.4.4 kernel for TQM850L
3036 Created: Wed Jul 19 02:34:59 2000
3037 Image Type: PowerPC Linux Kernel Image (uncompressed)
3038 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3039 Load Address: 0x00000000
3040 Entry Point: 0x00000000
3043 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3044 when your kernel is intended to use an initial ramdisk:
3046 -> tools/mkimage -n 'Simple Ramdisk Image' \
3047 > -A ppc -O linux -T ramdisk -C gzip \
3048 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3049 Image Name: Simple Ramdisk Image
3050 Created: Wed Jan 12 14:01:50 2000
3051 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3052 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3053 Load Address: 0x00000000
3054 Entry Point: 0x00000000
3057 Installing a Linux Image:
3058 -------------------------
3060 To downloading a U-Boot image over the serial (console) interface,
3061 you must convert the image to S-Record format:
3063 objcopy -I binary -O srec examples/image examples/image.srec
3065 The 'objcopy' does not understand the information in the U-Boot
3066 image header, so the resulting S-Record file will be relative to
3067 address 0x00000000. To load it to a given address, you need to
3068 specify the target address as 'offset' parameter with the 'loads'
3071 Example: install the image to address 0x40100000 (which on the
3072 TQM8xxL is in the first Flash bank):
3074 => erase 40100000 401FFFFF
3080 ## Ready for S-Record download ...
3081 ~>examples/image.srec
3082 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3084 15989 15990 15991 15992
3085 [file transfer complete]
3087 ## Start Addr = 0x00000000
3090 You can check the success of the download using the 'iminfo' command;
3091 this includes a checksum verification so you can be sure no data
3092 corruption happened:
3096 ## Checking Image at 40100000 ...
3097 Image Name: 2.2.13 for initrd on TQM850L
3098 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3099 Data Size: 335725 Bytes = 327 kB = 0 MB
3100 Load Address: 00000000
3101 Entry Point: 0000000c
3102 Verifying Checksum ... OK
3108 The "bootm" command is used to boot an application that is stored in
3109 memory (RAM or Flash). In case of a Linux kernel image, the contents
3110 of the "bootargs" environment variable is passed to the kernel as
3111 parameters. You can check and modify this variable using the
3112 "printenv" and "setenv" commands:
3115 => printenv bootargs
3116 bootargs=root=/dev/ram
3118 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3120 => printenv bootargs
3121 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3124 ## Booting Linux kernel at 40020000 ...
3125 Image Name: 2.2.13 for NFS on TQM850L
3126 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3127 Data Size: 381681 Bytes = 372 kB = 0 MB
3128 Load Address: 00000000
3129 Entry Point: 0000000c
3130 Verifying Checksum ... OK
3131 Uncompressing Kernel Image ... OK
3132 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
3133 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3134 time_init: decrementer frequency = 187500000/60
3135 Calibrating delay loop... 49.77 BogoMIPS
3136 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3139 If you want to boot a Linux kernel with initial ram disk, you pass
3140 the memory addresses of both the kernel and the initrd image (PPBCOOT
3141 format!) to the "bootm" command:
3143 => imi 40100000 40200000
3145 ## Checking Image at 40100000 ...
3146 Image Name: 2.2.13 for initrd on TQM850L
3147 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3148 Data Size: 335725 Bytes = 327 kB = 0 MB
3149 Load Address: 00000000
3150 Entry Point: 0000000c
3151 Verifying Checksum ... OK
3153 ## Checking Image at 40200000 ...
3154 Image Name: Simple Ramdisk Image
3155 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3156 Data Size: 566530 Bytes = 553 kB = 0 MB
3157 Load Address: 00000000
3158 Entry Point: 00000000
3159 Verifying Checksum ... OK
3161 => bootm 40100000 40200000
3162 ## Booting Linux kernel at 40100000 ...
3163 Image Name: 2.2.13 for initrd on TQM850L
3164 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3165 Data Size: 335725 Bytes = 327 kB = 0 MB
3166 Load Address: 00000000
3167 Entry Point: 0000000c
3168 Verifying Checksum ... OK
3169 Uncompressing Kernel Image ... OK
3170 ## Loading RAMDisk Image at 40200000 ...
3171 Image Name: Simple Ramdisk Image
3172 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3173 Data Size: 566530 Bytes = 553 kB = 0 MB
3174 Load Address: 00000000
3175 Entry Point: 00000000
3176 Verifying Checksum ... OK
3177 Loading Ramdisk ... OK
3178 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
3179 Boot arguments: root=/dev/ram
3180 time_init: decrementer frequency = 187500000/60
3181 Calibrating delay loop... 49.77 BogoMIPS
3183 RAMDISK: Compressed image found at block 0
3184 VFS: Mounted root (ext2 filesystem).
3188 Boot Linux and pass a flat device tree:
3191 First, U-Boot must be compiled with the appropriate defines. See the section
3192 titled "Linux Kernel Interface" above for a more in depth explanation. The
3193 following is an example of how to start a kernel and pass an updated
3199 oft=oftrees/mpc8540ads.dtb
3200 => tftp $oftaddr $oft
3201 Speed: 1000, full duplex
3203 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3204 Filename 'oftrees/mpc8540ads.dtb'.
3205 Load address: 0x300000
3208 Bytes transferred = 4106 (100a hex)
3209 => tftp $loadaddr $bootfile
3210 Speed: 1000, full duplex
3212 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3214 Load address: 0x200000
3215 Loading:############
3217 Bytes transferred = 1029407 (fb51f hex)
3222 => bootm $loadaddr - $oftaddr
3223 ## Booting image at 00200000 ...
3224 Image Name: Linux-2.6.17-dirty
3225 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3226 Data Size: 1029343 Bytes = 1005.2 kB
3227 Load Address: 00000000
3228 Entry Point: 00000000
3229 Verifying Checksum ... OK
3230 Uncompressing Kernel Image ... OK
3231 Booting using flat device tree at 0x300000
3232 Using MPC85xx ADS machine description
3233 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3237 More About U-Boot Image Types:
3238 ------------------------------
3240 U-Boot supports the following image types:
3242 "Standalone Programs" are directly runnable in the environment
3243 provided by U-Boot; it is expected that (if they behave
3244 well) you can continue to work in U-Boot after return from
3245 the Standalone Program.
3246 "OS Kernel Images" are usually images of some Embedded OS which
3247 will take over control completely. Usually these programs
3248 will install their own set of exception handlers, device
3249 drivers, set up the MMU, etc. - this means, that you cannot
3250 expect to re-enter U-Boot except by resetting the CPU.
3251 "RAMDisk Images" are more or less just data blocks, and their
3252 parameters (address, size) are passed to an OS kernel that is
3254 "Multi-File Images" contain several images, typically an OS
3255 (Linux) kernel image and one or more data images like
3256 RAMDisks. This construct is useful for instance when you want
3257 to boot over the network using BOOTP etc., where the boot
3258 server provides just a single image file, but you want to get
3259 for instance an OS kernel and a RAMDisk image.
3261 "Multi-File Images" start with a list of image sizes, each
3262 image size (in bytes) specified by an "uint32_t" in network
3263 byte order. This list is terminated by an "(uint32_t)0".
3264 Immediately after the terminating 0 follow the images, one by
3265 one, all aligned on "uint32_t" boundaries (size rounded up to
3266 a multiple of 4 bytes).
3268 "Firmware Images" are binary images containing firmware (like
3269 U-Boot or FPGA images) which usually will be programmed to
3272 "Script files" are command sequences that will be executed by
3273 U-Boot's command interpreter; this feature is especially
3274 useful when you configure U-Boot to use a real shell (hush)
3275 as command interpreter.
3281 One of the features of U-Boot is that you can dynamically load and
3282 run "standalone" applications, which can use some resources of
3283 U-Boot like console I/O functions or interrupt services.
3285 Two simple examples are included with the sources:
3290 'examples/hello_world.c' contains a small "Hello World" Demo
3291 application; it is automatically compiled when you build U-Boot.
3292 It's configured to run at address 0x00040004, so you can play with it
3296 ## Ready for S-Record download ...
3297 ~>examples/hello_world.srec
3298 1 2 3 4 5 6 7 8 9 10 11 ...
3299 [file transfer complete]
3301 ## Start Addr = 0x00040004
3303 => go 40004 Hello World! This is a test.
3304 ## Starting application at 0x00040004 ...
3315 Hit any key to exit ...
3317 ## Application terminated, rc = 0x0
3319 Another example, which demonstrates how to register a CPM interrupt
3320 handler with the U-Boot code, can be found in 'examples/timer.c'.
3321 Here, a CPM timer is set up to generate an interrupt every second.
3322 The interrupt service routine is trivial, just printing a '.'
3323 character, but this is just a demo program. The application can be
3324 controlled by the following keys:
3326 ? - print current values og the CPM Timer registers
3327 b - enable interrupts and start timer
3328 e - stop timer and disable interrupts
3329 q - quit application
3332 ## Ready for S-Record download ...
3333 ~>examples/timer.srec
3334 1 2 3 4 5 6 7 8 9 10 11 ...
3335 [file transfer complete]
3337 ## Start Addr = 0x00040004
3340 ## Starting application at 0x00040004 ...
3343 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3346 [q, b, e, ?] Set interval 1000000 us
3349 [q, b, e, ?] ........
3350 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3353 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3356 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3359 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3361 [q, b, e, ?] ...Stopping timer
3363 [q, b, e, ?] ## Application terminated, rc = 0x0
3369 Over time, many people have reported problems when trying to use the
3370 "minicom" terminal emulation program for serial download. I (wd)
3371 consider minicom to be broken, and recommend not to use it. Under
3372 Unix, I recommend to use C-Kermit for general purpose use (and
3373 especially for kermit binary protocol download ("loadb" command), and
3374 use "cu" for S-Record download ("loads" command).
3376 Nevertheless, if you absolutely want to use it try adding this
3377 configuration to your "File transfer protocols" section:
3379 Name Program Name U/D FullScr IO-Red. Multi
3380 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3381 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3387 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3388 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3390 Building requires a cross environment; it is known to work on
3391 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3392 need gmake since the Makefiles are not compatible with BSD make).
3393 Note that the cross-powerpc package does not install include files;
3394 attempting to build U-Boot will fail because <machine/ansi.h> is
3395 missing. This file has to be installed and patched manually:
3397 # cd /usr/pkg/cross/powerpc-netbsd/include
3399 # ln -s powerpc machine
3400 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3401 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3403 Native builds *don't* work due to incompatibilities between native
3404 and U-Boot include files.
3406 Booting assumes that (the first part of) the image booted is a
3407 stage-2 loader which in turn loads and then invokes the kernel
3408 proper. Loader sources will eventually appear in the NetBSD source
3409 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3410 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3413 Implementation Internals:
3414 =========================
3416 The following is not intended to be a complete description of every
3417 implementation detail. However, it should help to understand the
3418 inner workings of U-Boot and make it easier to port it to custom
3422 Initial Stack, Global Data:
3423 ---------------------------
3425 The implementation of U-Boot is complicated by the fact that U-Boot
3426 starts running out of ROM (flash memory), usually without access to
3427 system RAM (because the memory controller is not initialized yet).
3428 This means that we don't have writable Data or BSS segments, and BSS
3429 is not initialized as zero. To be able to get a C environment working
3430 at all, we have to allocate at least a minimal stack. Implementation
3431 options for this are defined and restricted by the CPU used: Some CPU
3432 models provide on-chip memory (like the IMMR area on MPC8xx and
3433 MPC826x processors), on others (parts of) the data cache can be
3434 locked as (mis-) used as memory, etc.
3436 Chris Hallinan posted a good summary of these issues to the
3437 u-boot-users mailing list:
3439 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3440 From: "Chris Hallinan" <clh@net1plus.com>
3441 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3444 Correct me if I'm wrong, folks, but the way I understand it
3445 is this: Using DCACHE as initial RAM for Stack, etc, does not
3446 require any physical RAM backing up the cache. The cleverness
3447 is that the cache is being used as a temporary supply of
3448 necessary storage before the SDRAM controller is setup. It's
3449 beyond the scope of this list to expain the details, but you
3450 can see how this works by studying the cache architecture and
3451 operation in the architecture and processor-specific manuals.
3453 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3454 is another option for the system designer to use as an
3455 initial stack/ram area prior to SDRAM being available. Either
3456 option should work for you. Using CS 4 should be fine if your
3457 board designers haven't used it for something that would
3458 cause you grief during the initial boot! It is frequently not
3461 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3462 with your processor/board/system design. The default value
3463 you will find in any recent u-boot distribution in
3464 walnut.h should work for you. I'd set it to a value larger
3465 than your SDRAM module. If you have a 64MB SDRAM module, set
3466 it above 400_0000. Just make sure your board has no resources
3467 that are supposed to respond to that address! That code in
3468 start.S has been around a while and should work as is when
3469 you get the config right.
3474 It is essential to remember this, since it has some impact on the C
3475 code for the initialization procedures:
3477 * Initialized global data (data segment) is read-only. Do not attempt
3480 * Do not use any unitialized global data (or implicitely initialized
3481 as zero data - BSS segment) at all - this is undefined, initiali-
3482 zation is performed later (when relocating to RAM).
3484 * Stack space is very limited. Avoid big data buffers or things like
3487 Having only the stack as writable memory limits means we cannot use
3488 normal global data to share information beween the code. But it
3489 turned out that the implementation of U-Boot can be greatly
3490 simplified by making a global data structure (gd_t) available to all
3491 functions. We could pass a pointer to this data as argument to _all_
3492 functions, but this would bloat the code. Instead we use a feature of
3493 the GCC compiler (Global Register Variables) to share the data: we
3494 place a pointer (gd) to the global data into a register which we
3495 reserve for this purpose.
3497 When choosing a register for such a purpose we are restricted by the
3498 relevant (E)ABI specifications for the current architecture, and by
3499 GCC's implementation.
3501 For PowerPC, the following registers have specific use:
3503 R2: reserved for system use
3504 R3-R4: parameter passing and return values
3505 R5-R10: parameter passing
3506 R13: small data area pointer
3510 (U-Boot also uses R14 as internal GOT pointer.)
3512 ==> U-Boot will use R2 to hold a pointer to the global data
3514 Note: on PPC, we could use a static initializer (since the
3515 address of the global data structure is known at compile time),
3516 but it turned out that reserving a register results in somewhat
3517 smaller code - although the code savings are not that big (on
3518 average for all boards 752 bytes for the whole U-Boot image,
3519 624 text + 127 data).
3521 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3522 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3524 ==> U-Boot will use P5 to hold a pointer to the global data
3526 On ARM, the following registers are used:
3528 R0: function argument word/integer result
3529 R1-R3: function argument word
3531 R10: stack limit (used only if stack checking if enabled)
3532 R11: argument (frame) pointer
3533 R12: temporary workspace
3536 R15: program counter
3538 ==> U-Boot will use R8 to hold a pointer to the global data
3540 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3541 or current versions of GCC may "optimize" the code too much.
3546 U-Boot runs in system state and uses physical addresses, i.e. the
3547 MMU is not used either for address mapping nor for memory protection.
3549 The available memory is mapped to fixed addresses using the memory
3550 controller. In this process, a contiguous block is formed for each
3551 memory type (Flash, SDRAM, SRAM), even when it consists of several
3552 physical memory banks.
3554 U-Boot is installed in the first 128 kB of the first Flash bank (on
3555 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3556 booting and sizing and initializing DRAM, the code relocates itself
3557 to the upper end of DRAM. Immediately below the U-Boot code some
3558 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3559 configuration setting]. Below that, a structure with global Board
3560 Info data is placed, followed by the stack (growing downward).
3562 Additionally, some exception handler code is copied to the low 8 kB
3563 of DRAM (0x00000000 ... 0x00001FFF).
3565 So a typical memory configuration with 16 MB of DRAM could look like
3568 0x0000 0000 Exception Vector code
3571 0x0000 2000 Free for Application Use
3577 0x00FB FF20 Monitor Stack (Growing downward)
3578 0x00FB FFAC Board Info Data and permanent copy of global data
3579 0x00FC 0000 Malloc Arena
3582 0x00FE 0000 RAM Copy of Monitor Code
3583 ... eventually: LCD or video framebuffer
3584 ... eventually: pRAM (Protected RAM - unchanged by reset)
3585 0x00FF FFFF [End of RAM]
3588 System Initialization:
3589 ----------------------
3591 In the reset configuration, U-Boot starts at the reset entry point
3592 (on most PowerPC systens at address 0x00000100). Because of the reset
3593 configuration for CS0# this is a mirror of the onboard Flash memory.
3594 To be able to re-map memory U-Boot then jumps to its link address.
3595 To be able to implement the initialization code in C, a (small!)
3596 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3597 which provide such a feature like MPC8xx or MPC8260), or in a locked
3598 part of the data cache. After that, U-Boot initializes the CPU core,
3599 the caches and the SIU.
3601 Next, all (potentially) available memory banks are mapped using a
3602 preliminary mapping. For example, we put them on 512 MB boundaries
3603 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3604 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3605 programmed for SDRAM access. Using the temporary configuration, a
3606 simple memory test is run that determines the size of the SDRAM
3609 When there is more than one SDRAM bank, and the banks are of
3610 different size, the largest is mapped first. For equal size, the first
3611 bank (CS2#) is mapped first. The first mapping is always for address
3612 0x00000000, with any additional banks following immediately to create
3613 contiguous memory starting from 0.
3615 Then, the monitor installs itself at the upper end of the SDRAM area
3616 and allocates memory for use by malloc() and for the global Board
3617 Info data; also, the exception vector code is copied to the low RAM
3618 pages, and the final stack is set up.
3620 Only after this relocation will you have a "normal" C environment;
3621 until that you are restricted in several ways, mostly because you are
3622 running from ROM, and because the code will have to be relocated to a
3626 U-Boot Porting Guide:
3627 ----------------------
3629 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3633 int main (int argc, char *argv[])
3635 sighandler_t no_more_time;
3637 signal (SIGALRM, no_more_time);
3638 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3640 if (available_money > available_manpower) {
3641 pay consultant to port U-Boot;
3645 Download latest U-Boot source;
3647 Subscribe to u-boot-users mailing list;
3650 email ("Hi, I am new to U-Boot, how do I get started?");
3654 Read the README file in the top level directory;
3655 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3656 Read the source, Luke;
3659 if (available_money > toLocalCurrency ($2500)) {
3662 Add a lot of aggravation and time;
3665 Create your own board support subdirectory;
3667 Create your own board config file;
3671 Add / modify source code;
3675 email ("Hi, I am having problems...");
3677 Send patch file to Wolfgang;
3682 void no_more_time (int sig)
3691 All contributions to U-Boot should conform to the Linux kernel
3692 coding style; see the file "Documentation/CodingStyle" and the script
3693 "scripts/Lindent" in your Linux kernel source directory. In sources
3694 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3695 spaces before parameters to function calls) is actually used.
3697 Source files originating from a different project (for example the
3698 MTD subsystem) are generally exempt from these guidelines and are not
3699 reformated to ease subsequent migration to newer versions of those
3702 Please note that U-Boot is implemented in C (and to some small parts in
3703 Assembler); no C++ is used, so please do not use C++ style comments (//)
3706 Please also stick to the following formatting rules:
3707 - remove any trailing white space
3708 - use TAB characters for indentation, not spaces
3709 - make sure NOT to use DOS '\r\n' line feeds
3710 - do not add more than 2 empty lines to source files
3711 - do not add trailing empty lines to source files
3713 Submissions which do not conform to the standards may be returned
3714 with a request to reformat the changes.
3720 Since the number of patches for U-Boot is growing, we need to
3721 establish some rules. Submissions which do not conform to these rules
3722 may be rejected, even when they contain important and valuable stuff.
3724 Patches shall be sent to the u-boot-users mailing list.
3726 When you send a patch, please include the following information with
3729 * For bug fixes: a description of the bug and how your patch fixes
3730 this bug. Please try to include a way of demonstrating that the
3731 patch actually fixes something.
3733 * For new features: a description of the feature and your
3736 * A CHANGELOG entry as plaintext (separate from the patch)
3738 * For major contributions, your entry to the CREDITS file
3740 * When you add support for a new board, don't forget to add this
3741 board to the MAKEALL script, too.
3743 * If your patch adds new configuration options, don't forget to
3744 document these in the README file.
3746 * The patch itself. If you are accessing the CVS repository use "cvs
3747 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3748 version of diff does not support these options, then get the latest
3749 version of GNU diff.
3751 The current directory when running this command shall be the top
3752 level directory of the U-Boot source tree, or it's parent directory
3753 (i. e. please make sure that your patch includes sufficient
3754 directory information for the affected files).
3756 We accept patches as plain text, MIME attachments or as uuencoded
3759 * If one logical set of modifications affects or creates several
3760 files, all these changes shall be submitted in a SINGLE patch file.
3762 * Changesets that contain different, unrelated modifications shall be
3763 submitted as SEPARATE patches, one patch per changeset.
3768 * Before sending the patch, run the MAKEALL script on your patched
3769 source tree and make sure that no errors or warnings are reported
3770 for any of the boards.
3772 * Keep your modifications to the necessary minimum: A patch
3773 containing several unrelated changes or arbitrary reformats will be
3774 returned with a request to re-formatting / split it.
3776 * If you modify existing code, make sure that your new code does not
3777 add to the memory footprint of the code ;-) Small is beautiful!
3778 When adding new features, these should compile conditionally only
3779 (using #ifdef), and the resulting code with the new feature
3780 disabled must not need more memory than the old code without your
3783 * Remember that there is a size limit of 40 kB per message on the
3784 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob