2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
140 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
141 - mips Files specific to MIPS CPUs
142 - mpc5xx Files specific to Freescale MPC5xx CPUs
143 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
144 - mpc8xx Files specific to Freescale MPC8xx CPUs
145 - mpc8220 Files specific to Freescale MPC8220 CPUs
146 - mpc824x Files specific to Freescale MPC824x CPUs
147 - mpc8260 Files specific to Freescale MPC8260 CPUs
148 - mpc85xx Files specific to Freescale MPC85xx CPUs
149 - nios Files specific to Altera NIOS CPUs
150 - nios2 Files specific to Altera Nios-II CPUs
151 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
152 - pxa Files specific to Intel XScale PXA CPUs
153 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
154 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
155 - disk Code for disk drive partition handling
156 - doc Documentation (don't expect too much)
157 - drivers Commonly used device drivers
158 - dtt Digital Thermometer and Thermostat drivers
159 - examples Example code for standalone applications, etc.
160 - include Header Files
161 - lib_arm Files generic to ARM architecture
162 - lib_avr32 Files generic to AVR32 architecture
163 - lib_generic Files generic to all architectures
164 - lib_i386 Files generic to i386 architecture
165 - lib_m68k Files generic to m68k architecture
166 - lib_mips Files generic to MIPS architecture
167 - lib_nios Files generic to NIOS architecture
168 - lib_ppc Files generic to PowerPC architecture
169 - libfdt Library files to support flattened device trees
170 - net Networking code
171 - post Power On Self Test
172 - rtc Real Time Clock drivers
173 - tools Tools to build S-Record or U-Boot images, etc.
175 Software Configuration:
176 =======================
178 Configuration is usually done using C preprocessor defines; the
179 rationale behind that is to avoid dead code whenever possible.
181 There are two classes of configuration variables:
183 * Configuration _OPTIONS_:
184 These are selectable by the user and have names beginning with
187 * Configuration _SETTINGS_:
188 These depend on the hardware etc. and should not be meddled with if
189 you don't know what you're doing; they have names beginning with
192 Later we will add a configuration tool - probably similar to or even
193 identical to what's used for the Linux kernel. Right now, we have to
194 do the configuration by hand, which means creating some symbolic
195 links and editing some configuration files. We use the TQM8xxL boards
199 Selection of Processor Architecture and Board Type:
200 ---------------------------------------------------
202 For all supported boards there are ready-to-use default
203 configurations available; just type "make <board_name>_config".
205 Example: For a TQM823L module type:
210 For the Cogent platform, you need to specify the cpu type as well;
211 e.g. "make cogent_mpc8xx_config". And also configure the cogent
212 directory according to the instructions in cogent/README.
215 Configuration Options:
216 ----------------------
218 Configuration depends on the combination of board and CPU type; all
219 such information is kept in a configuration file
220 "include/configs/<board_name>.h".
222 Example: For a TQM823L module, all configuration settings are in
223 "include/configs/TQM823L.h".
226 Many of the options are named exactly as the corresponding Linux
227 kernel configuration options. The intention is to make it easier to
228 build a config tool - later.
231 The following options need to be configured:
233 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
235 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
237 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
238 Define exactly one, e.g. CONFIG_ATSTK1002
240 - CPU Module Type: (if CONFIG_COGENT is defined)
241 Define exactly one of
243 --- FIXME --- not tested yet:
244 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
245 CONFIG_CMA287_23, CONFIG_CMA287_50
247 - Motherboard Type: (if CONFIG_COGENT is defined)
248 Define exactly one of
249 CONFIG_CMA101, CONFIG_CMA102
251 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
252 Define one or more of
255 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
256 Define one or more of
257 CONFIG_LCD_HEARTBEAT - update a character position on
258 the lcd display every second with
261 - Board flavour: (if CONFIG_MPC8260ADS is defined)
264 CFG_8260ADS - original MPC8260ADS
265 CFG_8266ADS - MPC8266ADS
266 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
267 CFG_8272ADS - MPC8272ADS
269 - MPC824X Family Member (if CONFIG_MPC824X is defined)
270 Define exactly one of
271 CONFIG_MPC8240, CONFIG_MPC8245
273 - 8xx CPU Options: (if using an MPC8xx cpu)
274 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
275 get_gclk_freq() cannot work
276 e.g. if there is no 32KHz
277 reference PIT/RTC clock
278 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
281 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
284 CONFIG_8xx_CPUCLK_DEFAULT
285 See doc/README.MPC866
289 Define this to measure the actual CPU clock instead
290 of relying on the correctness of the configured
291 values. Mostly useful for board bringup to make sure
292 the PLL is locked at the intended frequency. Note
293 that this requires a (stable) reference clock (32 kHz
294 RTC clock or CFG_8XX_XIN)
296 - Intel Monahans options:
297 CFG_MONAHANS_RUN_MODE_OSC_RATIO
299 Defines the Monahans run mode to oscillator
300 ratio. Valid values are 8, 16, 24, 31. The core
301 frequency is this value multiplied by 13 MHz.
303 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
305 Defines the Monahans turbo mode to oscillator
306 ratio. Valid values are 1 (default if undefined) and
307 2. The core frequency as calculated above is multiplied
310 - Linux Kernel Interface:
313 U-Boot stores all clock information in Hz
314 internally. For binary compatibility with older Linux
315 kernels (which expect the clocks passed in the
316 bd_info data to be in MHz) the environment variable
317 "clocks_in_mhz" can be defined so that U-Boot
318 converts clock data to MHZ before passing it to the
320 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
321 "clocks_in_mhz=1" is automatically included in the
324 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
326 When transfering memsize parameter to linux, some versions
327 expect it to be in bytes, others in MB.
328 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
330 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
332 New kernel versions are expecting firmware settings to be
333 passed using flattened device trees (based on open firmware
337 * New libfdt-based support
338 * Adds the "fdt" command
339 * The bootm command automatically updates the fdt
342 * Deprecated, see CONFIG_OF_LIBFDT
343 * Original ft_build.c-based support
344 * Automatically modifies the dft as part of the bootm command
345 * The environment variable "disable_of", when set,
346 disables this functionality.
348 OF_CPU - The proper name of the cpus node.
349 OF_SOC - The proper name of the soc node.
350 OF_TBCLK - The timebase frequency.
351 OF_STDOUT_PATH - The path to the console device
353 boards with QUICC Engines require OF_QE to set UCC mac addresses
357 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
358 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
359 will have a copy of the bd_t. Space should be
360 pre-allocated in the dts for the bd_t.
362 CONFIG_OF_HAS_UBOOT_ENV
364 * CONFIG_OF_LIBFDT - enables the "fdt env" command
365 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
366 will have a copy of u-boot's environment variables
368 CONFIG_OF_BOARD_SETUP
370 Board code has addition modification that it wants to make
371 to the flat device tree before handing it off to the kernel
375 This define fills in the correct boot cpu in the boot
376 param header, the default value is zero if undefined.
381 Define this if you want support for Amba PrimeCell PL010 UARTs.
385 Define this if you want support for Amba PrimeCell PL011 UARTs.
389 If you have Amba PrimeCell PL011 UARTs, set this variable to
390 the clock speed of the UARTs.
394 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
395 define this to a list of base addresses for each (supported)
396 port. See e.g. include/configs/versatile.h
400 Depending on board, define exactly one serial port
401 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
402 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
403 console by defining CONFIG_8xx_CONS_NONE
405 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
406 port routines must be defined elsewhere
407 (i.e. serial_init(), serial_getc(), ...)
410 Enables console device for a color framebuffer. Needs following
411 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
412 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
414 VIDEO_HW_RECTFILL graphic chip supports
417 VIDEO_HW_BITBLT graphic chip supports
418 bit-blit (cf. smiLynxEM)
419 VIDEO_VISIBLE_COLS visible pixel columns
421 VIDEO_VISIBLE_ROWS visible pixel rows
422 VIDEO_PIXEL_SIZE bytes per pixel
423 VIDEO_DATA_FORMAT graphic data format
424 (0-5, cf. cfb_console.c)
425 VIDEO_FB_ADRS framebuffer address
426 VIDEO_KBD_INIT_FCT keyboard int fct
427 (i.e. i8042_kbd_init())
428 VIDEO_TSTC_FCT test char fct
430 VIDEO_GETC_FCT get char fct
432 CONFIG_CONSOLE_CURSOR cursor drawing on/off
433 (requires blink timer
435 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
436 CONFIG_CONSOLE_TIME display time/date info in
438 (requires CONFIG_CMD_DATE)
439 CONFIG_VIDEO_LOGO display Linux logo in
441 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
442 linux_logo.h for logo.
443 Requires CONFIG_VIDEO_LOGO
444 CONFIG_CONSOLE_EXTRA_INFO
445 addional board info beside
448 When CONFIG_CFB_CONSOLE is defined, video console is
449 default i/o. Serial console can be forced with
450 environment 'console=serial'.
452 When CONFIG_SILENT_CONSOLE is defined, all console
453 messages (by U-Boot and Linux!) can be silenced with
454 the "silent" environment variable. See
455 doc/README.silent for more information.
458 CONFIG_BAUDRATE - in bps
459 Select one of the baudrates listed in
460 CFG_BAUDRATE_TABLE, see below.
461 CFG_BRGCLK_PRESCALE, baudrate prescale
463 - Interrupt driven serial port input:
464 CONFIG_SERIAL_SOFTWARE_FIFO
467 Use an interrupt handler for receiving data on the
468 serial port. It also enables using hardware handshake
469 (RTS/CTS) and UART's built-in FIFO. Set the number of
470 bytes the interrupt driven input buffer should have.
472 Leave undefined to disable this feature, including
473 disable the buffer and hardware handshake.
475 - Console UART Number:
479 If defined internal UART1 (and not UART0) is used
480 as default U-Boot console.
482 - Boot Delay: CONFIG_BOOTDELAY - in seconds
483 Delay before automatically booting the default image;
484 set to -1 to disable autoboot.
486 See doc/README.autoboot for these options that
487 work with CONFIG_BOOTDELAY. None are required.
488 CONFIG_BOOT_RETRY_TIME
489 CONFIG_BOOT_RETRY_MIN
490 CONFIG_AUTOBOOT_KEYED
491 CONFIG_AUTOBOOT_PROMPT
492 CONFIG_AUTOBOOT_DELAY_STR
493 CONFIG_AUTOBOOT_STOP_STR
494 CONFIG_AUTOBOOT_DELAY_STR2
495 CONFIG_AUTOBOOT_STOP_STR2
496 CONFIG_ZERO_BOOTDELAY_CHECK
497 CONFIG_RESET_TO_RETRY
501 Only needed when CONFIG_BOOTDELAY is enabled;
502 define a command string that is automatically executed
503 when no character is read on the console interface
504 within "Boot Delay" after reset.
507 This can be used to pass arguments to the bootm
508 command. The value of CONFIG_BOOTARGS goes into the
509 environment value "bootargs".
511 CONFIG_RAMBOOT and CONFIG_NFSBOOT
512 The value of these goes into the environment as
513 "ramboot" and "nfsboot" respectively, and can be used
514 as a convenience, when switching between booting from
520 When this option is #defined, the existence of the
521 environment variable "preboot" will be checked
522 immediately before starting the CONFIG_BOOTDELAY
523 countdown and/or running the auto-boot command resp.
524 entering interactive mode.
526 This feature is especially useful when "preboot" is
527 automatically generated or modified. For an example
528 see the LWMON board specific code: here "preboot" is
529 modified when the user holds down a certain
530 combination of keys on the (special) keyboard when
533 - Serial Download Echo Mode:
535 If defined to 1, all characters received during a
536 serial download (using the "loads" command) are
537 echoed back. This might be needed by some terminal
538 emulations (like "cu"), but may as well just take
539 time on others. This setting #define's the initial
540 value of the "loads_echo" environment variable.
542 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
544 Select one of the baudrates listed in
545 CFG_BAUDRATE_TABLE, see below.
548 Monitor commands can be included or excluded
549 from the build by using the #include files
550 "config_cmd_all.h" and #undef'ing unwanted
551 commands, or using "config_cmd_default.h"
552 and augmenting with additional #define's
555 The default command configuration includes all commands
556 except those marked below with a "*".
558 CONFIG_CMD_ASKENV * ask for env variable
559 CONFIG_CMD_AUTOSCRIPT Autoscript Support
560 CONFIG_CMD_BDI bdinfo
561 CONFIG_CMD_BEDBUG * Include BedBug Debugger
562 CONFIG_CMD_BMP * BMP support
563 CONFIG_CMD_BSP * Board specific commands
564 CONFIG_CMD_BOOTD bootd
565 CONFIG_CMD_CACHE * icache, dcache
566 CONFIG_CMD_CONSOLE coninfo
567 CONFIG_CMD_DATE * support for RTC, date/time...
568 CONFIG_CMD_DHCP * DHCP support
569 CONFIG_CMD_DIAG * Diagnostics
570 CONFIG_CMD_DOC * Disk-On-Chip Support
571 CONFIG_CMD_DTT * Digital Therm and Thermostat
572 CONFIG_CMD_ECHO echo arguments
573 CONFIG_CMD_EEPROM * EEPROM read/write support
574 CONFIG_CMD_ELF * bootelf, bootvx
575 CONFIG_CMD_ENV saveenv
576 CONFIG_CMD_FDC * Floppy Disk Support
577 CONFIG_CMD_FAT * FAT partition support
578 CONFIG_CMD_FDOS * Dos diskette Support
579 CONFIG_CMD_FLASH flinfo, erase, protect
580 CONFIG_CMD_FPGA FPGA device initialization support
581 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
582 CONFIG_CMD_I2C * I2C serial bus support
583 CONFIG_CMD_IDE * IDE harddisk support
584 CONFIG_CMD_IMI iminfo
585 CONFIG_CMD_IMLS List all found images
586 CONFIG_CMD_IMMAP * IMMR dump support
587 CONFIG_CMD_IRQ * irqinfo
588 CONFIG_CMD_ITEST Integer/string test of 2 values
589 CONFIG_CMD_JFFS2 * JFFS2 Support
590 CONFIG_CMD_KGDB * kgdb
591 CONFIG_CMD_LOADB loadb
592 CONFIG_CMD_LOADS loads
593 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
595 CONFIG_CMD_MISC Misc functions like sleep etc
596 CONFIG_CMD_MMC * MMC memory mapped support
597 CONFIG_CMD_MII * MII utility commands
598 CONFIG_CMD_NAND * NAND support
599 CONFIG_CMD_NET bootp, tftpboot, rarpboot
600 CONFIG_CMD_PCI * pciinfo
601 CONFIG_CMD_PCMCIA * PCMCIA support
602 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
604 CONFIG_CMD_PORTIO * Port I/O
605 CONFIG_CMD_REGINFO * Register dump
606 CONFIG_CMD_RUN run command in env variable
607 CONFIG_CMD_SAVES * save S record dump
608 CONFIG_CMD_SCSI * SCSI Support
609 CONFIG_CMD_SDRAM * print SDRAM configuration information
610 (requires CONFIG_CMD_I2C)
611 CONFIG_CMD_SETGETDCR Support for DCR Register access
613 CONFIG_CMD_SPI * SPI serial bus support
614 CONFIG_CMD_USB * USB support
615 CONFIG_CMD_VFD * VFD support (TRAB)
616 CONFIG_CMD_BSP * Board SPecific functions
617 CONFIG_CMD_CDP * Cisco Discover Protocol support
618 CONFIG_CMD_FSL * Microblaze FSL support
621 EXAMPLE: If you want all functions except of network
622 support you can write:
624 #include "config_cmd_all.h"
625 #undef CONFIG_CMD_NET
628 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
630 Note: Don't enable the "icache" and "dcache" commands
631 (configuration option CONFIG_CMD_CACHE) unless you know
632 what you (and your U-Boot users) are doing. Data
633 cache cannot be enabled on systems like the 8xx or
634 8260 (where accesses to the IMMR region must be
635 uncached), and it cannot be disabled on all other
636 systems where we (mis-) use the data cache to hold an
637 initial stack and some data.
640 XXX - this list needs to get updated!
644 If this variable is defined, it enables watchdog
645 support. There must be support in the platform specific
646 code for a watchdog. For the 8xx and 8260 CPUs, the
647 SIU Watchdog feature is enabled in the SYPCR
651 CONFIG_VERSION_VARIABLE
652 If this variable is defined, an environment variable
653 named "ver" is created by U-Boot showing the U-Boot
654 version as printed by the "version" command.
655 This variable is readonly.
659 When CONFIG_CMD_DATE is selected, the type of the RTC
660 has to be selected, too. Define exactly one of the
663 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
664 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
665 CONFIG_RTC_MC146818 - use MC146818 RTC
666 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
667 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
668 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
669 CONFIG_RTC_DS164x - use Dallas DS164x RTC
670 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
672 Note that if the RTC uses I2C, then the I2C interface
673 must also be configured. See I2C Support, below.
677 When CONFIG_TIMESTAMP is selected, the timestamp
678 (date and time) of an image is printed by image
679 commands like bootm or iminfo. This option is
680 automatically enabled when you select CONFIG_CMD_DATE .
683 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
684 and/or CONFIG_ISO_PARTITION
686 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
687 CONFIG_CMD_SCSI) you must configure support for at least
688 one partition type as well.
691 CONFIG_IDE_RESET_ROUTINE - this is defined in several
692 board configurations files but used nowhere!
694 CONFIG_IDE_RESET - is this is defined, IDE Reset will
695 be performed by calling the function
696 ide_set_reset(int reset)
697 which has to be defined in a board specific file
702 Set this to enable ATAPI support.
707 Set this to enable support for disks larger than 137GB
708 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
709 Whithout these , LBA48 support uses 32bit variables and will 'only'
710 support disks up to 2.1TB.
713 When enabled, makes the IDE subsystem use 64bit sector addresses.
717 At the moment only there is only support for the
718 SYM53C8XX SCSI controller; define
719 CONFIG_SCSI_SYM53C8XX to enable it.
721 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
722 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
723 CFG_SCSI_MAX_LUN] can be adjusted to define the
724 maximum numbers of LUNs, SCSI ID's and target
726 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
728 - NETWORK Support (PCI):
730 Support for Intel 8254x gigabit chips.
733 Support for Intel 82557/82559/82559ER chips.
734 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
735 write routine for first time initialisation.
738 Support for Digital 2114x chips.
739 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
740 modem chip initialisation (KS8761/QS6611).
743 Support for National dp83815 chips.
746 Support for National dp8382[01] gigabit chips.
748 - NETWORK Support (other):
750 CONFIG_DRIVER_LAN91C96
751 Support for SMSC's LAN91C96 chips.
754 Define this to hold the physical address
755 of the LAN91C96's I/O space
757 CONFIG_LAN91C96_USE_32_BIT
758 Define this to enable 32 bit addressing
760 CONFIG_DRIVER_SMC91111
761 Support for SMSC's LAN91C111 chip
764 Define this to hold the physical address
765 of the device (I/O space)
767 CONFIG_SMC_USE_32_BIT
768 Define this if data bus is 32 bits
770 CONFIG_SMC_USE_IOFUNCS
771 Define this to use i/o functions instead of macros
772 (some hardware wont work with macros)
775 At the moment only the UHCI host controller is
776 supported (PIP405, MIP405, MPC5200); define
777 CONFIG_USB_UHCI to enable it.
778 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
779 and define CONFIG_USB_STORAGE to enable the USB
782 Supported are USB Keyboards and USB Floppy drives
784 MPC5200 USB requires additional defines:
786 for 528 MHz Clock: 0x0001bbbb
788 for differential drivers: 0x00001000
789 for single ended drivers: 0x00005000
791 May be defined to allow interrupt polling
792 instead of using asynchronous interrupts
795 Define the below if you wish to use the USB console.
796 Once firmware is rebuilt from a serial console issue the
797 command "setenv stdin usbtty; setenv stdout usbtty" and
798 attach your usb cable. The Unix command "dmesg" should print
799 it has found a new device. The environment variable usbtty
800 can be set to gserial or cdc_acm to enable your device to
801 appear to a USB host as a Linux gserial device or a
802 Common Device Class Abstract Control Model serial device.
803 If you select usbtty = gserial you should be able to enumerate
805 # modprobe usbserial vendor=0xVendorID product=0xProductID
806 else if using cdc_acm, simply setting the environment
807 variable usbtty to be cdc_acm should suffice. The following
808 might be defined in YourBoardName.h
811 Define this to build a UDC device
814 Define this to have a tty type of device available to
815 talk to the UDC device
817 CFG_CONSOLE_IS_IN_ENV
818 Define this if you want stdin, stdout &/or stderr to
822 CFG_USB_EXTC_CLK 0xBLAH
823 Derive USB clock from external clock "blah"
824 - CFG_USB_EXTC_CLK 0x02
826 CFG_USB_BRG_CLK 0xBLAH
827 Derive USB clock from brgclk
828 - CFG_USB_BRG_CLK 0x04
830 If you have a USB-IF assigned VendorID then you may wish to
831 define your own vendor specific values either in BoardName.h
832 or directly in usbd_vendor_info.h. If you don't define
833 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
834 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
835 should pretend to be a Linux device to it's target host.
837 CONFIG_USBD_MANUFACTURER
838 Define this string as the name of your company for
839 - CONFIG_USBD_MANUFACTURER "my company"
841 CONFIG_USBD_PRODUCT_NAME
842 Define this string as the name of your product
843 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
846 Define this as your assigned Vendor ID from the USB
847 Implementors Forum. This *must* be a genuine Vendor ID
848 to avoid polluting the USB namespace.
849 - CONFIG_USBD_VENDORID 0xFFFF
851 CONFIG_USBD_PRODUCTID
852 Define this as the unique Product ID
854 - CONFIG_USBD_PRODUCTID 0xFFFF
858 The MMC controller on the Intel PXA is supported. To
859 enable this define CONFIG_MMC. The MMC can be
860 accessed from the boot prompt by mapping the device
861 to physical memory similar to flash. Command line is
862 enabled with CONFIG_CMD_MMC. The MMC driver also works with
863 the FAT fs. This is enabled with CONFIG_CMD_FAT.
865 - Journaling Flash filesystem support:
866 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
867 CONFIG_JFFS2_NAND_DEV
868 Define these for a default partition on a NAND device
870 CFG_JFFS2_FIRST_SECTOR,
871 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
872 Define these for a default partition on a NOR device
875 Define this to create an own partition. You have to provide a
876 function struct part_info* jffs2_part_info(int part_num)
878 If you define only one JFFS2 partition you may also want to
879 #define CFG_JFFS_SINGLE_PART 1
880 to disable the command chpart. This is the default when you
881 have not defined a custom partition
886 Define this to enable standard (PC-Style) keyboard
890 Standard PC keyboard driver with US (is default) and
891 GERMAN key layout (switch via environment 'keymap=de') support.
892 Export function i8042_kbd_init, i8042_tstc and i8042_getc
893 for cfb_console. Supports cursor blinking.
898 Define this to enable video support (for output to
903 Enable Chips & Technologies 69000 Video chip
905 CONFIG_VIDEO_SMI_LYNXEM
906 Enable Silicon Motion SMI 712/710/810 Video chip. The
907 video output is selected via environment 'videoout'
908 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
911 For the CT69000 and SMI_LYNXEM drivers, videomode is
912 selected via environment 'videomode'. Two diferent ways
914 - "videomode=num" 'num' is a standard LiLo mode numbers.
915 Following standard modes are supported (* is default):
917 Colors 640x480 800x600 1024x768 1152x864 1280x1024
918 -------------+---------------------------------------------
919 8 bits | 0x301* 0x303 0x305 0x161 0x307
920 15 bits | 0x310 0x313 0x316 0x162 0x319
921 16 bits | 0x311 0x314 0x317 0x163 0x31A
922 24 bits | 0x312 0x315 0x318 ? 0x31B
923 -------------+---------------------------------------------
924 (i.e. setenv videomode 317; saveenv; reset;)
926 - "videomode=bootargs" all the video parameters are parsed
927 from the bootargs. (See drivers/video/videomodes.c)
930 CONFIG_VIDEO_SED13806
931 Enable Epson SED13806 driver. This driver supports 8bpp
932 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
933 or CONFIG_VIDEO_SED13806_16BPP
938 Define this to enable a custom keyboard support.
939 This simply calls drv_keyboard_init() which must be
940 defined in your board-specific files.
941 The only board using this so far is RBC823.
943 - LCD Support: CONFIG_LCD
945 Define this to enable LCD support (for output to LCD
946 display); also select one of the supported displays
947 by defining one of these:
949 CONFIG_NEC_NL6448AC33:
951 NEC NL6448AC33-18. Active, color, single scan.
953 CONFIG_NEC_NL6448BC20
955 NEC NL6448BC20-08. 6.5", 640x480.
956 Active, color, single scan.
958 CONFIG_NEC_NL6448BC33_54
960 NEC NL6448BC33-54. 10.4", 640x480.
961 Active, color, single scan.
965 Sharp 320x240. Active, color, single scan.
966 It isn't 16x9, and I am not sure what it is.
968 CONFIG_SHARP_LQ64D341
970 Sharp LQ64D341 display, 640x480.
971 Active, color, single scan.
975 HLD1045 display, 640x480.
976 Active, color, single scan.
980 Optrex CBL50840-2 NF-FW 99 22 M5
982 Hitachi LMG6912RPFC-00T
986 320x240. Black & white.
988 Normally display is black on white background; define
989 CFG_WHITE_ON_BLACK to get it inverted.
991 - Splash Screen Support: CONFIG_SPLASH_SCREEN
993 If this option is set, the environment is checked for
994 a variable "splashimage". If found, the usual display
995 of logo, copyright and system information on the LCD
996 is suppressed and the BMP image at the address
997 specified in "splashimage" is loaded instead. The
998 console is redirected to the "nulldev", too. This
999 allows for a "silent" boot where a splash screen is
1000 loaded very quickly after power-on.
1002 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1004 If this option is set, additionally to standard BMP
1005 images, gzipped BMP images can be displayed via the
1006 splashscreen support or the bmp command.
1008 - Compression support:
1011 If this option is set, support for bzip2 compressed
1012 images is included. If not, only uncompressed and gzip
1013 compressed images are supported.
1015 NOTE: the bzip2 algorithm requires a lot of RAM, so
1016 the malloc area (as defined by CFG_MALLOC_LEN) should
1022 The address of PHY on MII bus.
1024 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1026 The clock frequency of the MII bus
1030 If this option is set, support for speed/duplex
1031 detection of Gigabit PHY is included.
1033 CONFIG_PHY_RESET_DELAY
1035 Some PHY like Intel LXT971A need extra delay after
1036 reset before any MII register access is possible.
1037 For such PHY, set this option to the usec delay
1038 required. (minimum 300usec for LXT971A)
1040 CONFIG_PHY_CMD_DELAY (ppc4xx)
1042 Some PHY like Intel LXT971A need extra delay after
1043 command issued before MII status register can be read
1050 Define a default value for ethernet address to use
1051 for the respective ethernet interface, in case this
1052 is not determined automatically.
1057 Define a default value for the IP address to use for
1058 the default ethernet interface, in case this is not
1059 determined through e.g. bootp.
1061 - Server IP address:
1064 Defines a default value for theIP address of a TFTP
1065 server to contact when using the "tftboot" command.
1067 - Multicast TFTP Mode:
1070 Defines whether you want to support multicast TFTP as per
1071 rfc-2090; for example to work with atftp. Lets lots of targets
1072 tftp down the same boot image concurrently. Note: the ethernet
1073 driver in use must provide a function: mcast() to join/leave a
1076 CONFIG_BOOTP_RANDOM_DELAY
1077 - BOOTP Recovery Mode:
1078 CONFIG_BOOTP_RANDOM_DELAY
1080 If you have many targets in a network that try to
1081 boot using BOOTP, you may want to avoid that all
1082 systems send out BOOTP requests at precisely the same
1083 moment (which would happen for instance at recovery
1084 from a power failure, when all systems will try to
1085 boot, thus flooding the BOOTP server. Defining
1086 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1087 inserted before sending out BOOTP requests. The
1088 following delays are inserted then:
1090 1st BOOTP request: delay 0 ... 1 sec
1091 2nd BOOTP request: delay 0 ... 2 sec
1092 3rd BOOTP request: delay 0 ... 4 sec
1094 BOOTP requests: delay 0 ... 8 sec
1096 - DHCP Advanced Options:
1097 You can fine tune the DHCP functionality by defining
1098 CONFIG_BOOTP_* symbols:
1100 CONFIG_BOOTP_SUBNETMASK
1101 CONFIG_BOOTP_GATEWAY
1102 CONFIG_BOOTP_HOSTNAME
1103 CONFIG_BOOTP_NISDOMAIN
1104 CONFIG_BOOTP_BOOTPATH
1105 CONFIG_BOOTP_BOOTFILESIZE
1108 CONFIG_BOOTP_SEND_HOSTNAME
1109 CONFIG_BOOTP_NTPSERVER
1110 CONFIG_BOOTP_TIMEOFFSET
1111 CONFIG_BOOTP_VENDOREX
1113 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1114 environment variable, not the BOOTP server.
1116 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1117 serverip from a DHCP server, it is possible that more
1118 than one DNS serverip is offered to the client.
1119 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1120 serverip will be stored in the additional environment
1121 variable "dnsip2". The first DNS serverip is always
1122 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1125 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1126 to do a dynamic update of a DNS server. To do this, they
1127 need the hostname of the DHCP requester.
1128 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1129 of the "hostname" environment variable is passed as
1130 option 12 to the DHCP server.
1133 CONFIG_CDP_DEVICE_ID
1135 The device id used in CDP trigger frames.
1137 CONFIG_CDP_DEVICE_ID_PREFIX
1139 A two character string which is prefixed to the MAC address
1144 A printf format string which contains the ascii name of
1145 the port. Normally is set to "eth%d" which sets
1146 eth0 for the first ethernet, eth1 for the second etc.
1148 CONFIG_CDP_CAPABILITIES
1150 A 32bit integer which indicates the device capabilities;
1151 0x00000010 for a normal host which does not forwards.
1155 An ascii string containing the version of the software.
1159 An ascii string containing the name of the platform.
1163 A 32bit integer sent on the trigger.
1165 CONFIG_CDP_POWER_CONSUMPTION
1167 A 16bit integer containing the power consumption of the
1168 device in .1 of milliwatts.
1170 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1172 A byte containing the id of the VLAN.
1174 - Status LED: CONFIG_STATUS_LED
1176 Several configurations allow to display the current
1177 status using a LED. For instance, the LED will blink
1178 fast while running U-Boot code, stop blinking as
1179 soon as a reply to a BOOTP request was received, and
1180 start blinking slow once the Linux kernel is running
1181 (supported by a status LED driver in the Linux
1182 kernel). Defining CONFIG_STATUS_LED enables this
1185 - CAN Support: CONFIG_CAN_DRIVER
1187 Defining CONFIG_CAN_DRIVER enables CAN driver support
1188 on those systems that support this (optional)
1189 feature, like the TQM8xxL modules.
1191 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1193 These enable I2C serial bus commands. Defining either of
1194 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1195 include the appropriate I2C driver for the selected cpu.
1197 This will allow you to use i2c commands at the u-boot
1198 command line (as long as you set CONFIG_CMD_I2C in
1199 CONFIG_COMMANDS) and communicate with i2c based realtime
1200 clock chips. See common/cmd_i2c.c for a description of the
1201 command line interface.
1203 CONFIG_I2C_CMD_TREE is a recommended option that places
1204 all I2C commands under a single 'i2c' root command. The
1205 older 'imm', 'imd', 'iprobe' etc. commands are considered
1206 deprecated and may disappear in the future.
1208 CONFIG_HARD_I2C selects a hardware I2C controller.
1210 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1211 bit-banging) driver instead of CPM or similar hardware
1214 There are several other quantities that must also be
1215 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1217 In both cases you will need to define CFG_I2C_SPEED
1218 to be the frequency (in Hz) at which you wish your i2c bus
1219 to run and CFG_I2C_SLAVE to be the address of this node (ie
1220 the cpu's i2c node address).
1222 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1223 sets the cpu up as a master node and so its address should
1224 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1225 p.16-473). So, set CFG_I2C_SLAVE to 0.
1227 That's all that's required for CONFIG_HARD_I2C.
1229 If you use the software i2c interface (CONFIG_SOFT_I2C)
1230 then the following macros need to be defined (examples are
1231 from include/configs/lwmon.h):
1235 (Optional). Any commands necessary to enable the I2C
1236 controller or configure ports.
1238 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1242 (Only for MPC8260 CPU). The I/O port to use (the code
1243 assumes both bits are on the same port). Valid values
1244 are 0..3 for ports A..D.
1248 The code necessary to make the I2C data line active
1249 (driven). If the data line is open collector, this
1252 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1256 The code necessary to make the I2C data line tri-stated
1257 (inactive). If the data line is open collector, this
1260 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1264 Code that returns TRUE if the I2C data line is high,
1267 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1271 If <bit> is TRUE, sets the I2C data line high. If it
1272 is FALSE, it clears it (low).
1274 eg: #define I2C_SDA(bit) \
1275 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1276 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1280 If <bit> is TRUE, sets the I2C clock line high. If it
1281 is FALSE, it clears it (low).
1283 eg: #define I2C_SCL(bit) \
1284 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1285 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1289 This delay is invoked four times per clock cycle so this
1290 controls the rate of data transfer. The data rate thus
1291 is 1 / (I2C_DELAY * 4). Often defined to be something
1294 #define I2C_DELAY udelay(2)
1298 When a board is reset during an i2c bus transfer
1299 chips might think that the current transfer is still
1300 in progress. On some boards it is possible to access
1301 the i2c SCLK line directly, either by using the
1302 processor pin as a GPIO or by having a second pin
1303 connected to the bus. If this option is defined a
1304 custom i2c_init_board() routine in boards/xxx/board.c
1305 is run early in the boot sequence.
1307 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1309 This option enables configuration of bi_iic_fast[] flags
1310 in u-boot bd_info structure based on u-boot environment
1311 variable "i2cfast". (see also i2cfast)
1313 CONFIG_I2C_MULTI_BUS
1315 This option allows the use of multiple I2C buses, each of which
1316 must have a controller. At any point in time, only one bus is
1317 active. To switch to a different bus, use the 'i2c dev' command.
1318 Note that bus numbering is zero-based.
1322 This option specifies a list of I2C devices that will be skipped
1323 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1324 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1325 pairs. Otherwise, specify a 1D array of device addresses
1328 #undef CONFIG_I2C_MULTI_BUS
1329 #define CFG_I2C_NOPROBES {0x50,0x68}
1331 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1333 #define CONFIG_I2C_MULTI_BUS
1334 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1336 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1340 If defined, then this indicates the I2C bus number for DDR SPD.
1341 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1345 If defined, then this indicates the I2C bus number for the RTC.
1346 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1350 If defined, then this indicates the I2C bus number for the DTT.
1351 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1355 Define this option if you want to use Freescale's I2C driver in
1356 drivers/i2c/fsl_i2c.c.
1359 - SPI Support: CONFIG_SPI
1361 Enables SPI driver (so far only tested with
1362 SPI EEPROM, also an instance works with Crystal A/D and
1363 D/As on the SACSng board)
1367 Enables extended (16-bit) SPI EEPROM addressing.
1368 (symmetrical to CONFIG_I2C_X)
1372 Enables a software (bit-bang) SPI driver rather than
1373 using hardware support. This is a general purpose
1374 driver that only requires three general I/O port pins
1375 (two outputs, one input) to function. If this is
1376 defined, the board configuration must define several
1377 SPI configuration items (port pins to use, etc). For
1378 an example, see include/configs/sacsng.h.
1380 - FPGA Support: CONFIG_FPGA
1382 Enables FPGA subsystem.
1384 CONFIG_FPGA_<vendor>
1386 Enables support for specific chip vendors.
1389 CONFIG_FPGA_<family>
1391 Enables support for FPGA family.
1392 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1396 Specify the number of FPGA devices to support.
1398 CFG_FPGA_PROG_FEEDBACK
1400 Enable printing of hash marks during FPGA configuration.
1404 Enable checks on FPGA configuration interface busy
1405 status by the configuration function. This option
1406 will require a board or device specific function to
1411 If defined, a function that provides delays in the FPGA
1412 configuration driver.
1414 CFG_FPGA_CHECK_CTRLC
1415 Allow Control-C to interrupt FPGA configuration
1417 CFG_FPGA_CHECK_ERROR
1419 Check for configuration errors during FPGA bitfile
1420 loading. For example, abort during Virtex II
1421 configuration if the INIT_B line goes low (which
1422 indicated a CRC error).
1426 Maximum time to wait for the INIT_B line to deassert
1427 after PROB_B has been deasserted during a Virtex II
1428 FPGA configuration sequence. The default time is 500
1433 Maximum time to wait for BUSY to deassert during
1434 Virtex II FPGA configuration. The default is 5 mS.
1436 CFG_FPGA_WAIT_CONFIG
1438 Time to wait after FPGA configuration. The default is
1441 - Configuration Management:
1444 If defined, this string will be added to the U-Boot
1445 version information (U_BOOT_VERSION)
1447 - Vendor Parameter Protection:
1449 U-Boot considers the values of the environment
1450 variables "serial#" (Board Serial Number) and
1451 "ethaddr" (Ethernet Address) to be parameters that
1452 are set once by the board vendor / manufacturer, and
1453 protects these variables from casual modification by
1454 the user. Once set, these variables are read-only,
1455 and write or delete attempts are rejected. You can
1456 change this behviour:
1458 If CONFIG_ENV_OVERWRITE is #defined in your config
1459 file, the write protection for vendor parameters is
1460 completely disabled. Anybody can change or delete
1463 Alternatively, if you #define _both_ CONFIG_ETHADDR
1464 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1465 ethernet address is installed in the environment,
1466 which can be changed exactly ONCE by the user. [The
1467 serial# is unaffected by this, i. e. it remains
1473 Define this variable to enable the reservation of
1474 "protected RAM", i. e. RAM which is not overwritten
1475 by U-Boot. Define CONFIG_PRAM to hold the number of
1476 kB you want to reserve for pRAM. You can overwrite
1477 this default value by defining an environment
1478 variable "pram" to the number of kB you want to
1479 reserve. Note that the board info structure will
1480 still show the full amount of RAM. If pRAM is
1481 reserved, a new environment variable "mem" will
1482 automatically be defined to hold the amount of
1483 remaining RAM in a form that can be passed as boot
1484 argument to Linux, for instance like that:
1486 setenv bootargs ... mem=\${mem}
1489 This way you can tell Linux not to use this memory,
1490 either, which results in a memory region that will
1491 not be affected by reboots.
1493 *WARNING* If your board configuration uses automatic
1494 detection of the RAM size, you must make sure that
1495 this memory test is non-destructive. So far, the
1496 following board configurations are known to be
1499 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1500 HERMES, IP860, RPXlite, LWMON, LANTEC,
1501 PCU_E, FLAGADM, TQM8260
1506 Define this variable to stop the system in case of a
1507 fatal error, so that you have to reset it manually.
1508 This is probably NOT a good idea for an embedded
1509 system where you want to system to reboot
1510 automatically as fast as possible, but it may be
1511 useful during development since you can try to debug
1512 the conditions that lead to the situation.
1514 CONFIG_NET_RETRY_COUNT
1516 This variable defines the number of retries for
1517 network operations like ARP, RARP, TFTP, or BOOTP
1518 before giving up the operation. If not defined, a
1519 default value of 5 is used.
1521 - Command Interpreter:
1522 CONFIG_AUTO_COMPLETE
1524 Enable auto completion of commands using TAB.
1526 Note that this feature has NOT been implemented yet
1527 for the "hush" shell.
1532 Define this variable to enable the "hush" shell (from
1533 Busybox) as command line interpreter, thus enabling
1534 powerful command line syntax like
1535 if...then...else...fi conditionals or `&&' and '||'
1536 constructs ("shell scripts").
1538 If undefined, you get the old, much simpler behaviour
1539 with a somewhat smaller memory footprint.
1544 This defines the secondary prompt string, which is
1545 printed when the command interpreter needs more input
1546 to complete a command. Usually "> ".
1550 In the current implementation, the local variables
1551 space and global environment variables space are
1552 separated. Local variables are those you define by
1553 simply typing `name=value'. To access a local
1554 variable later on, you have write `$name' or
1555 `${name}'; to execute the contents of a variable
1556 directly type `$name' at the command prompt.
1558 Global environment variables are those you use
1559 setenv/printenv to work with. To run a command stored
1560 in such a variable, you need to use the run command,
1561 and you must not use the '$' sign to access them.
1563 To store commands and special characters in a
1564 variable, please use double quotation marks
1565 surrounding the whole text of the variable, instead
1566 of the backslashes before semicolons and special
1569 - Commandline Editing and History:
1570 CONFIG_CMDLINE_EDITING
1572 Enable editiong and History functions for interactive
1573 commandline input operations
1575 - Default Environment:
1576 CONFIG_EXTRA_ENV_SETTINGS
1578 Define this to contain any number of null terminated
1579 strings (variable = value pairs) that will be part of
1580 the default environment compiled into the boot image.
1582 For example, place something like this in your
1583 board's config file:
1585 #define CONFIG_EXTRA_ENV_SETTINGS \
1589 Warning: This method is based on knowledge about the
1590 internal format how the environment is stored by the
1591 U-Boot code. This is NOT an official, exported
1592 interface! Although it is unlikely that this format
1593 will change soon, there is no guarantee either.
1594 You better know what you are doing here.
1596 Note: overly (ab)use of the default environment is
1597 discouraged. Make sure to check other ways to preset
1598 the environment like the autoscript function or the
1601 - DataFlash Support:
1602 CONFIG_HAS_DATAFLASH
1604 Defining this option enables DataFlash features and
1605 allows to read/write in Dataflash via the standard
1608 - SystemACE Support:
1611 Adding this option adds support for Xilinx SystemACE
1612 chips attached via some sort of local bus. The address
1613 of the chip must alsh be defined in the
1614 CFG_SYSTEMACE_BASE macro. For example:
1616 #define CONFIG_SYSTEMACE
1617 #define CFG_SYSTEMACE_BASE 0xf0000000
1619 When SystemACE support is added, the "ace" device type
1620 becomes available to the fat commands, i.e. fatls.
1622 - TFTP Fixed UDP Port:
1625 If this is defined, the environment variable tftpsrcp
1626 is used to supply the TFTP UDP source port value.
1627 If tftpsrcp isn't defined, the normal pseudo-random port
1628 number generator is used.
1630 Also, the environment variable tftpdstp is used to supply
1631 the TFTP UDP destination port value. If tftpdstp isn't
1632 defined, the normal port 69 is used.
1634 The purpose for tftpsrcp is to allow a TFTP server to
1635 blindly start the TFTP transfer using the pre-configured
1636 target IP address and UDP port. This has the effect of
1637 "punching through" the (Windows XP) firewall, allowing
1638 the remainder of the TFTP transfer to proceed normally.
1639 A better solution is to properly configure the firewall,
1640 but sometimes that is not allowed.
1642 - Show boot progress:
1643 CONFIG_SHOW_BOOT_PROGRESS
1645 Defining this option allows to add some board-
1646 specific code (calling a user-provided function
1647 "show_boot_progress(int)") that enables you to show
1648 the system's boot progress on some display (for
1649 example, some LED's) on your board. At the moment,
1650 the following checkpoints are implemented:
1653 1 common/cmd_bootm.c before attempting to boot an image
1654 -1 common/cmd_bootm.c Image header has bad magic number
1655 2 common/cmd_bootm.c Image header has correct magic number
1656 -2 common/cmd_bootm.c Image header has bad checksum
1657 3 common/cmd_bootm.c Image header has correct checksum
1658 -3 common/cmd_bootm.c Image data has bad checksum
1659 4 common/cmd_bootm.c Image data has correct checksum
1660 -4 common/cmd_bootm.c Image is for unsupported architecture
1661 5 common/cmd_bootm.c Architecture check OK
1662 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1663 6 common/cmd_bootm.c Image Type check OK
1664 -6 common/cmd_bootm.c gunzip uncompression error
1665 -7 common/cmd_bootm.c Unimplemented compression type
1666 7 common/cmd_bootm.c Uncompression OK
1667 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1668 8 common/cmd_bootm.c Image Type check OK
1669 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1670 9 common/cmd_bootm.c Start initial ramdisk verification
1671 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1672 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1673 10 common/cmd_bootm.c Ramdisk header is OK
1674 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1675 11 common/cmd_bootm.c Ramdisk data has correct checksum
1676 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1677 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1678 13 common/cmd_bootm.c Start multifile image verification
1679 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1680 15 common/cmd_bootm.c All preparation done, transferring control to OS
1682 -30 lib_ppc/board.c Fatal error, hang the system
1683 -31 post/post.c POST test failed, detected by post_output_backlog()
1684 -32 post/post.c POST test failed, detected by post_run_single()
1686 34 common/cmd_doc.c before loading a Image from a DOC device
1687 -35 common/cmd_doc.c Bad usage of "doc" command
1688 35 common/cmd_doc.c correct usage of "doc" command
1689 -36 common/cmd_doc.c No boot device
1690 36 common/cmd_doc.c correct boot device
1691 -37 common/cmd_doc.c Unknown Chip ID on boot device
1692 37 common/cmd_doc.c correct chip ID found, device available
1693 -38 common/cmd_doc.c Read Error on boot device
1694 38 common/cmd_doc.c reading Image header from DOC device OK
1695 -39 common/cmd_doc.c Image header has bad magic number
1696 39 common/cmd_doc.c Image header has correct magic number
1697 -40 common/cmd_doc.c Error reading Image from DOC device
1698 40 common/cmd_doc.c Image header has correct magic number
1699 41 common/cmd_ide.c before loading a Image from a IDE device
1700 -42 common/cmd_ide.c Bad usage of "ide" command
1701 42 common/cmd_ide.c correct usage of "ide" command
1702 -43 common/cmd_ide.c No boot device
1703 43 common/cmd_ide.c boot device found
1704 -44 common/cmd_ide.c Device not available
1705 44 common/cmd_ide.c Device available
1706 -45 common/cmd_ide.c wrong partition selected
1707 45 common/cmd_ide.c partition selected
1708 -46 common/cmd_ide.c Unknown partition table
1709 46 common/cmd_ide.c valid partition table found
1710 -47 common/cmd_ide.c Invalid partition type
1711 47 common/cmd_ide.c correct partition type
1712 -48 common/cmd_ide.c Error reading Image Header on boot device
1713 48 common/cmd_ide.c reading Image Header from IDE device OK
1714 -49 common/cmd_ide.c Image header has bad magic number
1715 49 common/cmd_ide.c Image header has correct magic number
1716 -50 common/cmd_ide.c Image header has bad checksum
1717 50 common/cmd_ide.c Image header has correct checksum
1718 -51 common/cmd_ide.c Error reading Image from IDE device
1719 51 common/cmd_ide.c reading Image from IDE device OK
1720 52 common/cmd_nand.c before loading a Image from a NAND device
1721 -53 common/cmd_nand.c Bad usage of "nand" command
1722 53 common/cmd_nand.c correct usage of "nand" command
1723 -54 common/cmd_nand.c No boot device
1724 54 common/cmd_nand.c boot device found
1725 -55 common/cmd_nand.c Unknown Chip ID on boot device
1726 55 common/cmd_nand.c correct chip ID found, device available
1727 -56 common/cmd_nand.c Error reading Image Header on boot device
1728 56 common/cmd_nand.c reading Image Header from NAND device OK
1729 -57 common/cmd_nand.c Image header has bad magic number
1730 57 common/cmd_nand.c Image header has correct magic number
1731 -58 common/cmd_nand.c Error reading Image from NAND device
1732 58 common/cmd_nand.c reading Image from NAND device OK
1734 -60 common/env_common.c Environment has a bad CRC, using default
1736 64 net/eth.c starting with Ethernetconfiguration.
1737 -64 net/eth.c no Ethernet found.
1738 65 net/eth.c Ethernet found.
1740 -80 common/cmd_net.c usage wrong
1741 80 common/cmd_net.c before calling NetLoop()
1742 -81 common/cmd_net.c some error in NetLoop() occured
1743 81 common/cmd_net.c NetLoop() back without error
1744 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1745 82 common/cmd_net.c trying automatic boot
1746 83 common/cmd_net.c running autoscript
1747 -83 common/cmd_net.c some error in automatic boot or autoscript
1748 84 common/cmd_net.c end without errors
1753 [so far only for SMDK2400 and TRAB boards]
1755 - Modem support endable:
1756 CONFIG_MODEM_SUPPORT
1758 - RTS/CTS Flow control enable:
1761 - Modem debug support:
1762 CONFIG_MODEM_SUPPORT_DEBUG
1764 Enables debugging stuff (char screen[1024], dbg())
1765 for modem support. Useful only with BDI2000.
1767 - Interrupt support (PPC):
1769 There are common interrupt_init() and timer_interrupt()
1770 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1771 for cpu specific initialization. interrupt_init_cpu()
1772 should set decrementer_count to appropriate value. If
1773 cpu resets decrementer automatically after interrupt
1774 (ppc4xx) it should set decrementer_count to zero.
1775 timer_interrupt() calls timer_interrupt_cpu() for cpu
1776 specific handling. If board has watchdog / status_led
1777 / other_activity_monitor it works automatically from
1778 general timer_interrupt().
1782 In the target system modem support is enabled when a
1783 specific key (key combination) is pressed during
1784 power-on. Otherwise U-Boot will boot normally
1785 (autoboot). The key_pressed() fuction is called from
1786 board_init(). Currently key_pressed() is a dummy
1787 function, returning 1 and thus enabling modem
1790 If there are no modem init strings in the
1791 environment, U-Boot proceed to autoboot; the
1792 previous output (banner, info printfs) will be
1795 See also: doc/README.Modem
1798 Configuration Settings:
1799 -----------------------
1801 - CFG_LONGHELP: Defined when you want long help messages included;
1802 undefine this when you're short of memory.
1804 - CFG_PROMPT: This is what U-Boot prints on the console to
1805 prompt for user input.
1807 - CFG_CBSIZE: Buffer size for input from the Console
1809 - CFG_PBSIZE: Buffer size for Console output
1811 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1813 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1814 the application (usually a Linux kernel) when it is
1817 - CFG_BAUDRATE_TABLE:
1818 List of legal baudrate settings for this board.
1820 - CFG_CONSOLE_INFO_QUIET
1821 Suppress display of console information at boot.
1823 - CFG_CONSOLE_IS_IN_ENV
1824 If the board specific function
1825 extern int overwrite_console (void);
1826 returns 1, the stdin, stderr and stdout are switched to the
1827 serial port, else the settings in the environment are used.
1829 - CFG_CONSOLE_OVERWRITE_ROUTINE
1830 Enable the call to overwrite_console().
1832 - CFG_CONSOLE_ENV_OVERWRITE
1833 Enable overwrite of previous console environment settings.
1835 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1836 Begin and End addresses of the area used by the
1840 Enable an alternate, more extensive memory test.
1842 - CFG_MEMTEST_SCRATCH:
1843 Scratch address used by the alternate memory test
1844 You only need to set this if address zero isn't writeable
1846 - CFG_TFTP_LOADADDR:
1847 Default load address for network file downloads
1849 - CFG_LOADS_BAUD_CHANGE:
1850 Enable temporary baudrate change while serial download
1853 Physical start address of SDRAM. _Must_ be 0 here.
1856 Physical start address of Motherboard I/O (if using a
1860 Physical start address of Flash memory.
1863 Physical start address of boot monitor code (set by
1864 make config files to be same as the text base address
1865 (TEXT_BASE) used when linking) - same as
1866 CFG_FLASH_BASE when booting from flash.
1869 Size of memory reserved for monitor code, used to
1870 determine _at_compile_time_ (!) if the environment is
1871 embedded within the U-Boot image, or in a separate
1875 Size of DRAM reserved for malloc() use.
1878 Normally compressed uImages are limited to an
1879 uncompressed size of 8 MBytes. If this is not enough,
1880 you can define CFG_BOOTM_LEN in your board config file
1881 to adjust this setting to your needs.
1884 Maximum size of memory mapped by the startup code of
1885 the Linux kernel; all data that must be processed by
1886 the Linux kernel (bd_info, boot arguments, eventually
1887 initrd image) must be put below this limit.
1889 - CFG_MAX_FLASH_BANKS:
1890 Max number of Flash memory banks
1892 - CFG_MAX_FLASH_SECT:
1893 Max number of sectors on a Flash chip
1895 - CFG_FLASH_ERASE_TOUT:
1896 Timeout for Flash erase operations (in ms)
1898 - CFG_FLASH_WRITE_TOUT:
1899 Timeout for Flash write operations (in ms)
1901 - CFG_FLASH_LOCK_TOUT
1902 Timeout for Flash set sector lock bit operation (in ms)
1904 - CFG_FLASH_UNLOCK_TOUT
1905 Timeout for Flash clear lock bits operation (in ms)
1907 - CFG_FLASH_PROTECTION
1908 If defined, hardware flash sectors protection is used
1909 instead of U-Boot software protection.
1911 - CFG_DIRECT_FLASH_TFTP:
1913 Enable TFTP transfers directly to flash memory;
1914 without this option such a download has to be
1915 performed in two steps: (1) download to RAM, and (2)
1916 copy from RAM to flash.
1918 The two-step approach is usually more reliable, since
1919 you can check if the download worked before you erase
1920 the flash, but in some situations (when sytem RAM is
1921 too limited to allow for a tempory copy of the
1922 downloaded image) this option may be very useful.
1925 Define if the flash driver uses extra elements in the
1926 common flash structure for storing flash geometry.
1928 - CFG_FLASH_CFI_DRIVER
1929 This option also enables the building of the cfi_flash driver
1930 in the drivers directory
1932 - CFG_FLASH_QUIET_TEST
1933 If this option is defined, the common CFI flash doesn't
1934 print it's warning upon not recognized FLASH banks. This
1935 is useful, if some of the configured banks are only
1936 optionally available.
1938 - CFG_RX_ETH_BUFFER:
1939 Defines the number of ethernet receive buffers. On some
1940 ethernet controllers it is recommended to set this value
1941 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1942 buffers can be full shortly after enabling the interface
1943 on high ethernet traffic.
1944 Defaults to 4 if not defined.
1946 The following definitions that deal with the placement and management
1947 of environment data (variable area); in general, we support the
1948 following configurations:
1950 - CFG_ENV_IS_IN_FLASH:
1952 Define this if the environment is in flash memory.
1954 a) The environment occupies one whole flash sector, which is
1955 "embedded" in the text segment with the U-Boot code. This
1956 happens usually with "bottom boot sector" or "top boot
1957 sector" type flash chips, which have several smaller
1958 sectors at the start or the end. For instance, such a
1959 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1960 such a case you would place the environment in one of the
1961 4 kB sectors - with U-Boot code before and after it. With
1962 "top boot sector" type flash chips, you would put the
1963 environment in one of the last sectors, leaving a gap
1964 between U-Boot and the environment.
1968 Offset of environment data (variable area) to the
1969 beginning of flash memory; for instance, with bottom boot
1970 type flash chips the second sector can be used: the offset
1971 for this sector is given here.
1973 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1977 This is just another way to specify the start address of
1978 the flash sector containing the environment (instead of
1981 - CFG_ENV_SECT_SIZE:
1983 Size of the sector containing the environment.
1986 b) Sometimes flash chips have few, equal sized, BIG sectors.
1987 In such a case you don't want to spend a whole sector for
1992 If you use this in combination with CFG_ENV_IS_IN_FLASH
1993 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1994 of this flash sector for the environment. This saves
1995 memory for the RAM copy of the environment.
1997 It may also save flash memory if you decide to use this
1998 when your environment is "embedded" within U-Boot code,
1999 since then the remainder of the flash sector could be used
2000 for U-Boot code. It should be pointed out that this is
2001 STRONGLY DISCOURAGED from a robustness point of view:
2002 updating the environment in flash makes it always
2003 necessary to erase the WHOLE sector. If something goes
2004 wrong before the contents has been restored from a copy in
2005 RAM, your target system will be dead.
2007 - CFG_ENV_ADDR_REDUND
2010 These settings describe a second storage area used to hold
2011 a redundand copy of the environment data, so that there is
2012 a valid backup copy in case there is a power failure during
2013 a "saveenv" operation.
2015 BE CAREFUL! Any changes to the flash layout, and some changes to the
2016 source code will make it necessary to adapt <board>/u-boot.lds*
2020 - CFG_ENV_IS_IN_NVRAM:
2022 Define this if you have some non-volatile memory device
2023 (NVRAM, battery buffered SRAM) which you want to use for the
2029 These two #defines are used to determin the memory area you
2030 want to use for environment. It is assumed that this memory
2031 can just be read and written to, without any special
2034 BE CAREFUL! The first access to the environment happens quite early
2035 in U-Boot initalization (when we try to get the setting of for the
2036 console baudrate). You *MUST* have mappend your NVRAM area then, or
2039 Please note that even with NVRAM we still use a copy of the
2040 environment in RAM: we could work on NVRAM directly, but we want to
2041 keep settings there always unmodified except somebody uses "saveenv"
2042 to save the current settings.
2045 - CFG_ENV_IS_IN_EEPROM:
2047 Use this if you have an EEPROM or similar serial access
2048 device and a driver for it.
2053 These two #defines specify the offset and size of the
2054 environment area within the total memory of your EEPROM.
2056 - CFG_I2C_EEPROM_ADDR:
2057 If defined, specified the chip address of the EEPROM device.
2058 The default address is zero.
2060 - CFG_EEPROM_PAGE_WRITE_BITS:
2061 If defined, the number of bits used to address bytes in a
2062 single page in the EEPROM device. A 64 byte page, for example
2063 would require six bits.
2065 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2066 If defined, the number of milliseconds to delay between
2067 page writes. The default is zero milliseconds.
2069 - CFG_I2C_EEPROM_ADDR_LEN:
2070 The length in bytes of the EEPROM memory array address. Note
2071 that this is NOT the chip address length!
2073 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2074 EEPROM chips that implement "address overflow" are ones
2075 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2076 address and the extra bits end up in the "chip address" bit
2077 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2080 Note that we consider the length of the address field to
2081 still be one byte because the extra address bits are hidden
2082 in the chip address.
2085 The size in bytes of the EEPROM device.
2088 - CFG_ENV_IS_IN_DATAFLASH:
2090 Define this if you have a DataFlash memory device which you
2091 want to use for the environment.
2097 These three #defines specify the offset and size of the
2098 environment area within the total memory of your DataFlash placed
2099 at the specified address.
2101 - CFG_ENV_IS_IN_NAND:
2103 Define this if you have a NAND device which you want to use
2104 for the environment.
2109 These two #defines specify the offset and size of the environment
2110 area within the first NAND device.
2112 - CFG_ENV_OFFSET_REDUND
2114 This setting describes a second storage area of CFG_ENV_SIZE
2115 size used to hold a redundant copy of the environment data,
2116 so that there is a valid backup copy in case there is a
2117 power failure during a "saveenv" operation.
2119 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2120 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2121 the NAND devices block size.
2123 - CFG_SPI_INIT_OFFSET
2125 Defines offset to the initial SPI buffer area in DPRAM. The
2126 area is used at an early stage (ROM part) if the environment
2127 is configured to reside in the SPI EEPROM: We need a 520 byte
2128 scratch DPRAM area. It is used between the two initialization
2129 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2130 to be a good choice since it makes it far enough from the
2131 start of the data area as well as from the stack pointer.
2133 Please note that the environment is read-only until the monitor
2134 has been relocated to RAM and a RAM copy of the environment has been
2135 created; also, when using EEPROM you will have to use getenv_r()
2136 until then to read environment variables.
2138 The environment is protected by a CRC32 checksum. Before the monitor
2139 is relocated into RAM, as a result of a bad CRC you will be working
2140 with the compiled-in default environment - *silently*!!! [This is
2141 necessary, because the first environment variable we need is the
2142 "baudrate" setting for the console - if we have a bad CRC, we don't
2143 have any device yet where we could complain.]
2145 Note: once the monitor has been relocated, then it will complain if
2146 the default environment is used; a new CRC is computed as soon as you
2147 use the "saveenv" command to store a valid environment.
2149 - CFG_FAULT_ECHO_LINK_DOWN:
2150 Echo the inverted Ethernet link state to the fault LED.
2152 Note: If this option is active, then CFG_FAULT_MII_ADDR
2153 also needs to be defined.
2155 - CFG_FAULT_MII_ADDR:
2156 MII address of the PHY to check for the Ethernet link state.
2158 - CFG_64BIT_VSPRINTF:
2159 Makes vsprintf (and all *printf functions) support printing
2160 of 64bit values by using the L quantifier
2162 - CFG_64BIT_STRTOUL:
2163 Adds simple_strtoull that returns a 64bit value
2165 Low Level (hardware related) configuration options:
2166 ---------------------------------------------------
2168 - CFG_CACHELINE_SIZE:
2169 Cache Line Size of the CPU.
2172 Default address of the IMMR after system reset.
2174 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2175 and RPXsuper) to be able to adjust the position of
2176 the IMMR register after a reset.
2178 - Floppy Disk Support:
2179 CFG_FDC_DRIVE_NUMBER
2181 the default drive number (default value 0)
2185 defines the spacing between fdc chipset registers
2190 defines the offset of register from address. It
2191 depends on which part of the data bus is connected to
2192 the fdc chipset. (default value 0)
2194 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2195 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2198 if CFG_FDC_HW_INIT is defined, then the function
2199 fdc_hw_init() is called at the beginning of the FDC
2200 setup. fdc_hw_init() must be provided by the board
2201 source code. It is used to make hardware dependant
2204 - CFG_IMMR: Physical address of the Internal Memory.
2205 DO NOT CHANGE unless you know exactly what you're
2206 doing! (11-4) [MPC8xx/82xx systems only]
2208 - CFG_INIT_RAM_ADDR:
2210 Start address of memory area that can be used for
2211 initial data and stack; please note that this must be
2212 writable memory that is working WITHOUT special
2213 initialization, i. e. you CANNOT use normal RAM which
2214 will become available only after programming the
2215 memory controller and running certain initialization
2218 U-Boot uses the following memory types:
2219 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2220 - MPC824X: data cache
2221 - PPC4xx: data cache
2223 - CFG_GBL_DATA_OFFSET:
2225 Offset of the initial data structure in the memory
2226 area defined by CFG_INIT_RAM_ADDR. Usually
2227 CFG_GBL_DATA_OFFSET is chosen such that the initial
2228 data is located at the end of the available space
2229 (sometimes written as (CFG_INIT_RAM_END -
2230 CFG_INIT_DATA_SIZE), and the initial stack is just
2231 below that area (growing from (CFG_INIT_RAM_ADDR +
2232 CFG_GBL_DATA_OFFSET) downward.
2235 On the MPC824X (or other systems that use the data
2236 cache for initial memory) the address chosen for
2237 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2238 point to an otherwise UNUSED address space between
2239 the top of RAM and the start of the PCI space.
2241 - CFG_SIUMCR: SIU Module Configuration (11-6)
2243 - CFG_SYPCR: System Protection Control (11-9)
2245 - CFG_TBSCR: Time Base Status and Control (11-26)
2247 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2249 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2251 - CFG_SCCR: System Clock and reset Control Register (15-27)
2253 - CFG_OR_TIMING_SDRAM:
2257 periodic timer for refresh
2259 - CFG_DER: Debug Event Register (37-47)
2261 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2262 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2263 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2265 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2267 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2268 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2269 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2270 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2272 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2273 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2274 Machine Mode Register and Memory Periodic Timer
2275 Prescaler definitions (SDRAM timing)
2277 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2278 enable I2C microcode relocation patch (MPC8xx);
2279 define relocation offset in DPRAM [DSP2]
2281 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2282 enable SPI microcode relocation patch (MPC8xx);
2283 define relocation offset in DPRAM [SCC4]
2286 Use OSCM clock mode on MBX8xx board. Be careful,
2287 wrong setting might damage your board. Read
2288 doc/README.MBX before setting this variable!
2290 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2291 Offset of the bootmode word in DPRAM used by post
2292 (Power On Self Tests). This definition overrides
2293 #define'd default value in commproc.h resp.
2296 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2297 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2298 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2299 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2300 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2301 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2302 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2303 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2304 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2307 Get DDR timing information from an I2C EEPROM. Common with pluggable
2308 memory modules such as SODIMMs
2310 I2C address of the SPD EEPROM
2313 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2314 Note that the value must resolve to something your driver can deal with.
2316 - CFG_83XX_DDR_USES_CS0
2317 Only for 83xx systems. If specified, then DDR should be configured
2318 using CS0 and CS1 instead of CS2 and CS3.
2320 - CFG_83XX_DDR_USES_CS0
2321 Only for 83xx systems. If specified, then DDR should be configured
2322 using CS0 and CS1 instead of CS2 and CS3.
2324 - CONFIG_ETHER_ON_FEC[12]
2325 Define to enable FEC[12] on a 8xx series processor.
2327 - CONFIG_FEC[12]_PHY
2328 Define to the hardcoded PHY address which corresponds
2329 to the given FEC; i. e.
2330 #define CONFIG_FEC1_PHY 4
2331 means that the PHY with address 4 is connected to FEC1
2333 When set to -1, means to probe for first available.
2335 - CONFIG_FEC[12]_PHY_NORXERR
2336 The PHY does not have a RXERR line (RMII only).
2337 (so program the FEC to ignore it).
2340 Enable RMII mode for all FECs.
2341 Note that this is a global option, we can't
2342 have one FEC in standard MII mode and another in RMII mode.
2344 - CONFIG_CRC32_VERIFY
2345 Add a verify option to the crc32 command.
2348 => crc32 -v <address> <count> <crc32>
2350 Where address/count indicate a memory area
2351 and crc32 is the correct crc32 which the
2355 Add the "loopw" memory command. This only takes effect if
2356 the memory commands are activated globally (CONFIG_CMD_MEM).
2359 Add the "mdc" and "mwc" memory commands. These are cyclic
2364 This command will print 4 bytes (10,11,12,13) each 500 ms.
2366 => mwc.l 100 12345678 10
2367 This command will write 12345678 to address 100 all 10 ms.
2369 This only takes effect if the memory commands are activated
2370 globally (CONFIG_CMD_MEM).
2372 - CONFIG_SKIP_LOWLEVEL_INIT
2373 - CONFIG_SKIP_RELOCATE_UBOOT
2375 [ARM only] If these variables are defined, then
2376 certain low level initializations (like setting up
2377 the memory controller) are omitted and/or U-Boot does
2378 not relocate itself into RAM.
2379 Normally these variables MUST NOT be defined. The
2380 only exception is when U-Boot is loaded (to RAM) by
2381 some other boot loader or by a debugger which
2382 performs these intializations itself.
2385 Building the Software:
2386 ======================
2388 Building U-Boot has been tested in native PPC environments (on a
2389 PowerBook G3 running LinuxPPC 2000) and in cross environments
2390 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2393 If you are not using a native PPC environment, it is assumed that you
2394 have the GNU cross compiling tools available in your path and named
2395 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2396 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2397 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2400 CROSS_COMPILE = ppc_4xx-
2403 U-Boot is intended to be simple to build. After installing the
2404 sources you must configure U-Boot for one specific board type. This
2409 where "NAME_config" is the name of one of the existing
2410 configurations; see the main Makefile for supported names.
2412 Note: for some board special configuration names may exist; check if
2413 additional information is available from the board vendor; for
2414 instance, the TQM823L systems are available without (standard)
2415 or with LCD support. You can select such additional "features"
2416 when chosing the configuration, i. e.
2419 - will configure for a plain TQM823L, i. e. no LCD support
2421 make TQM823L_LCD_config
2422 - will configure for a TQM823L with U-Boot console on LCD
2427 Finally, type "make all", and you should get some working U-Boot
2428 images ready for download to / installation on your system:
2430 - "u-boot.bin" is a raw binary image
2431 - "u-boot" is an image in ELF binary format
2432 - "u-boot.srec" is in Motorola S-Record format
2434 By default the build is performed locally and the objects are saved
2435 in the source directory. One of the two methods can be used to change
2436 this behavior and build U-Boot to some external directory:
2438 1. Add O= to the make command line invocations:
2440 make O=/tmp/build distclean
2441 make O=/tmp/build NAME_config
2442 make O=/tmp/build all
2444 2. Set environment variable BUILD_DIR to point to the desired location:
2446 export BUILD_DIR=/tmp/build
2451 Note that the command line "O=" setting overrides the BUILD_DIR environment
2455 Please be aware that the Makefiles assume you are using GNU make, so
2456 for instance on NetBSD you might need to use "gmake" instead of
2460 If the system board that you have is not listed, then you will need
2461 to port U-Boot to your hardware platform. To do this, follow these
2464 1. Add a new configuration option for your board to the toplevel
2465 "Makefile" and to the "MAKEALL" script, using the existing
2466 entries as examples. Note that here and at many other places
2467 boards and other names are listed in alphabetical sort order. Please
2469 2. Create a new directory to hold your board specific code. Add any
2470 files you need. In your board directory, you will need at least
2471 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2472 3. Create a new configuration file "include/configs/<board>.h" for
2474 3. If you're porting U-Boot to a new CPU, then also create a new
2475 directory to hold your CPU specific code. Add any files you need.
2476 4. Run "make <board>_config" with your new name.
2477 5. Type "make", and you should get a working "u-boot.srec" file
2478 to be installed on your target system.
2479 6. Debug and solve any problems that might arise.
2480 [Of course, this last step is much harder than it sounds.]
2483 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2484 ==============================================================
2486 If you have modified U-Boot sources (for instance added a new board
2487 or support for new devices, a new CPU, etc.) you are expected to
2488 provide feedback to the other developers. The feedback normally takes
2489 the form of a "patch", i. e. a context diff against a certain (latest
2490 official or latest in CVS) version of U-Boot sources.
2492 But before you submit such a patch, please verify that your modifi-
2493 cation did not break existing code. At least make sure that *ALL* of
2494 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2495 just run the "MAKEALL" script, which will configure and build U-Boot
2496 for ALL supported system. Be warned, this will take a while. You can
2497 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2498 environment variable to the script, i. e. to use the cross tools from
2499 MontaVista's Hard Hat Linux you can type
2501 CROSS_COMPILE=ppc_8xx- MAKEALL
2503 or to build on a native PowerPC system you can type
2505 CROSS_COMPILE=' ' MAKEALL
2507 When using the MAKEALL script, the default behaviour is to build U-Boot
2508 in the source directory. This location can be changed by setting the
2509 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2510 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2511 <source dir>/LOG directory. This default location can be changed by
2512 setting the MAKEALL_LOGDIR environment variable. For example:
2514 export BUILD_DIR=/tmp/build
2515 export MAKEALL_LOGDIR=/tmp/log
2516 CROSS_COMPILE=ppc_8xx- MAKEALL
2518 With the above settings build objects are saved in the /tmp/build, log
2519 files are saved in the /tmp/log and the source tree remains clean during
2520 the whole build process.
2523 See also "U-Boot Porting Guide" below.
2526 Monitor Commands - Overview:
2527 ============================
2529 go - start application at address 'addr'
2530 run - run commands in an environment variable
2531 bootm - boot application image from memory
2532 bootp - boot image via network using BootP/TFTP protocol
2533 tftpboot- boot image via network using TFTP protocol
2534 and env variables "ipaddr" and "serverip"
2535 (and eventually "gatewayip")
2536 rarpboot- boot image via network using RARP/TFTP protocol
2537 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2538 loads - load S-Record file over serial line
2539 loadb - load binary file over serial line (kermit mode)
2541 mm - memory modify (auto-incrementing)
2542 nm - memory modify (constant address)
2543 mw - memory write (fill)
2545 cmp - memory compare
2546 crc32 - checksum calculation
2547 imd - i2c memory display
2548 imm - i2c memory modify (auto-incrementing)
2549 inm - i2c memory modify (constant address)
2550 imw - i2c memory write (fill)
2551 icrc32 - i2c checksum calculation
2552 iprobe - probe to discover valid I2C chip addresses
2553 iloop - infinite loop on address range
2554 isdram - print SDRAM configuration information
2555 sspi - SPI utility commands
2556 base - print or set address offset
2557 printenv- print environment variables
2558 setenv - set environment variables
2559 saveenv - save environment variables to persistent storage
2560 protect - enable or disable FLASH write protection
2561 erase - erase FLASH memory
2562 flinfo - print FLASH memory information
2563 bdinfo - print Board Info structure
2564 iminfo - print header information for application image
2565 coninfo - print console devices and informations
2566 ide - IDE sub-system
2567 loop - infinite loop on address range
2568 loopw - infinite write loop on address range
2569 mtest - simple RAM test
2570 icache - enable or disable instruction cache
2571 dcache - enable or disable data cache
2572 reset - Perform RESET of the CPU
2573 echo - echo args to console
2574 version - print monitor version
2575 help - print online help
2576 ? - alias for 'help'
2579 Monitor Commands - Detailed Description:
2580 ========================================
2584 For now: just type "help <command>".
2587 Environment Variables:
2588 ======================
2590 U-Boot supports user configuration using Environment Variables which
2591 can be made persistent by saving to Flash memory.
2593 Environment Variables are set using "setenv", printed using
2594 "printenv", and saved to Flash using "saveenv". Using "setenv"
2595 without a value can be used to delete a variable from the
2596 environment. As long as you don't save the environment you are
2597 working with an in-memory copy. In case the Flash area containing the
2598 environment is erased by accident, a default environment is provided.
2600 Some configuration options can be set using Environment Variables:
2602 baudrate - see CONFIG_BAUDRATE
2604 bootdelay - see CONFIG_BOOTDELAY
2606 bootcmd - see CONFIG_BOOTCOMMAND
2608 bootargs - Boot arguments when booting an RTOS image
2610 bootfile - Name of the image to load with TFTP
2612 autoload - if set to "no" (any string beginning with 'n'),
2613 "bootp" will just load perform a lookup of the
2614 configuration from the BOOTP server, but not try to
2615 load any image using TFTP
2617 autostart - if set to "yes", an image loaded using the "bootp",
2618 "rarpboot", "tftpboot" or "diskboot" commands will
2619 be automatically started (by internally calling
2622 If set to "no", a standalone image passed to the
2623 "bootm" command will be copied to the load address
2624 (and eventually uncompressed), but NOT be started.
2625 This can be used to load and uncompress arbitrary
2628 i2cfast - (PPC405GP|PPC405EP only)
2629 if set to 'y' configures Linux I2C driver for fast
2630 mode (400kHZ). This environment variable is used in
2631 initialization code. So, for changes to be effective
2632 it must be saved and board must be reset.
2634 initrd_high - restrict positioning of initrd images:
2635 If this variable is not set, initrd images will be
2636 copied to the highest possible address in RAM; this
2637 is usually what you want since it allows for
2638 maximum initrd size. If for some reason you want to
2639 make sure that the initrd image is loaded below the
2640 CFG_BOOTMAPSZ limit, you can set this environment
2641 variable to a value of "no" or "off" or "0".
2642 Alternatively, you can set it to a maximum upper
2643 address to use (U-Boot will still check that it
2644 does not overwrite the U-Boot stack and data).
2646 For instance, when you have a system with 16 MB
2647 RAM, and want to reserve 4 MB from use by Linux,
2648 you can do this by adding "mem=12M" to the value of
2649 the "bootargs" variable. However, now you must make
2650 sure that the initrd image is placed in the first
2651 12 MB as well - this can be done with
2653 setenv initrd_high 00c00000
2655 If you set initrd_high to 0xFFFFFFFF, this is an
2656 indication to U-Boot that all addresses are legal
2657 for the Linux kernel, including addresses in flash
2658 memory. In this case U-Boot will NOT COPY the
2659 ramdisk at all. This may be useful to reduce the
2660 boot time on your system, but requires that this
2661 feature is supported by your Linux kernel.
2663 ipaddr - IP address; needed for tftpboot command
2665 loadaddr - Default load address for commands like "bootp",
2666 "rarpboot", "tftpboot", "loadb" or "diskboot"
2668 loads_echo - see CONFIG_LOADS_ECHO
2670 serverip - TFTP server IP address; needed for tftpboot command
2672 bootretry - see CONFIG_BOOT_RETRY_TIME
2674 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2676 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2678 ethprime - When CONFIG_NET_MULTI is enabled controls which
2679 interface is used first.
2681 ethact - When CONFIG_NET_MULTI is enabled controls which
2682 interface is currently active. For example you
2683 can do the following
2685 => setenv ethact FEC ETHERNET
2686 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2687 => setenv ethact SCC ETHERNET
2688 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2690 netretry - When set to "no" each network operation will
2691 either succeed or fail without retrying.
2692 When set to "once" the network operation will
2693 fail when all the available network interfaces
2694 are tried once without success.
2695 Useful on scripts which control the retry operation
2698 tftpsrcport - If this is set, the value is used for TFTP's
2701 tftpdstport - If this is set, the value is used for TFTP's UDP
2702 destination port instead of the Well Know Port 69.
2704 vlan - When set to a value < 4095 the traffic over
2705 ethernet is encapsulated/received over 802.1q
2708 The following environment variables may be used and automatically
2709 updated by the network boot commands ("bootp" and "rarpboot"),
2710 depending the information provided by your boot server:
2712 bootfile - see above
2713 dnsip - IP address of your Domain Name Server
2714 dnsip2 - IP address of your secondary Domain Name Server
2715 gatewayip - IP address of the Gateway (Router) to use
2716 hostname - Target hostname
2718 netmask - Subnet Mask
2719 rootpath - Pathname of the root filesystem on the NFS server
2720 serverip - see above
2723 There are two special Environment Variables:
2725 serial# - contains hardware identification information such
2726 as type string and/or serial number
2727 ethaddr - Ethernet address
2729 These variables can be set only once (usually during manufacturing of
2730 the board). U-Boot refuses to delete or overwrite these variables
2731 once they have been set once.
2734 Further special Environment Variables:
2736 ver - Contains the U-Boot version string as printed
2737 with the "version" command. This variable is
2738 readonly (see CONFIG_VERSION_VARIABLE).
2741 Please note that changes to some configuration parameters may take
2742 only effect after the next boot (yes, that's just like Windoze :-).
2745 Command Line Parsing:
2746 =====================
2748 There are two different command line parsers available with U-Boot:
2749 the old "simple" one, and the much more powerful "hush" shell:
2751 Old, simple command line parser:
2752 --------------------------------
2754 - supports environment variables (through setenv / saveenv commands)
2755 - several commands on one line, separated by ';'
2756 - variable substitution using "... ${name} ..." syntax
2757 - special characters ('$', ';') can be escaped by prefixing with '\',
2759 setenv bootcmd bootm \${address}
2760 - You can also escape text by enclosing in single apostrophes, for example:
2761 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2766 - similar to Bourne shell, with control structures like
2767 if...then...else...fi, for...do...done; while...do...done,
2768 until...do...done, ...
2769 - supports environment ("global") variables (through setenv / saveenv
2770 commands) and local shell variables (through standard shell syntax
2771 "name=value"); only environment variables can be used with "run"
2777 (1) If a command line (or an environment variable executed by a "run"
2778 command) contains several commands separated by semicolon, and
2779 one of these commands fails, then the remaining commands will be
2782 (2) If you execute several variables with one call to run (i. e.
2783 calling run with a list af variables as arguments), any failing
2784 command will cause "run" to terminate, i. e. the remaining
2785 variables are not executed.
2787 Note for Redundant Ethernet Interfaces:
2788 =======================================
2790 Some boards come with redundant ethernet interfaces; U-Boot supports
2791 such configurations and is capable of automatic selection of a
2792 "working" interface when needed. MAC assignment works as follows:
2794 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2795 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2796 "eth1addr" (=>eth1), "eth2addr", ...
2798 If the network interface stores some valid MAC address (for instance
2799 in SROM), this is used as default address if there is NO correspon-
2800 ding setting in the environment; if the corresponding environment
2801 variable is set, this overrides the settings in the card; that means:
2803 o If the SROM has a valid MAC address, and there is no address in the
2804 environment, the SROM's address is used.
2806 o If there is no valid address in the SROM, and a definition in the
2807 environment exists, then the value from the environment variable is
2810 o If both the SROM and the environment contain a MAC address, and
2811 both addresses are the same, this MAC address is used.
2813 o If both the SROM and the environment contain a MAC address, and the
2814 addresses differ, the value from the environment is used and a
2817 o If neither SROM nor the environment contain a MAC address, an error
2824 The "boot" commands of this monitor operate on "image" files which
2825 can be basicly anything, preceeded by a special header; see the
2826 definitions in include/image.h for details; basicly, the header
2827 defines the following image properties:
2829 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2830 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2831 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2832 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2833 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2834 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2835 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2836 * Compression Type (uncompressed, gzip, bzip2)
2842 The header is marked by a special Magic Number, and both the header
2843 and the data portions of the image are secured against corruption by
2850 Although U-Boot should support any OS or standalone application
2851 easily, the main focus has always been on Linux during the design of
2854 U-Boot includes many features that so far have been part of some
2855 special "boot loader" code within the Linux kernel. Also, any
2856 "initrd" images to be used are no longer part of one big Linux image;
2857 instead, kernel and "initrd" are separate images. This implementation
2858 serves several purposes:
2860 - the same features can be used for other OS or standalone
2861 applications (for instance: using compressed images to reduce the
2862 Flash memory footprint)
2864 - it becomes much easier to port new Linux kernel versions because
2865 lots of low-level, hardware dependent stuff are done by U-Boot
2867 - the same Linux kernel image can now be used with different "initrd"
2868 images; of course this also means that different kernel images can
2869 be run with the same "initrd". This makes testing easier (you don't
2870 have to build a new "zImage.initrd" Linux image when you just
2871 change a file in your "initrd"). Also, a field-upgrade of the
2872 software is easier now.
2878 Porting Linux to U-Boot based systems:
2879 ---------------------------------------
2881 U-Boot cannot save you from doing all the necessary modifications to
2882 configure the Linux device drivers for use with your target hardware
2883 (no, we don't intend to provide a full virtual machine interface to
2886 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2888 Just make sure your machine specific header file (for instance
2889 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2890 Information structure as we define in include/u-boot.h, and make
2891 sure that your definition of IMAP_ADDR uses the same value as your
2892 U-Boot configuration in CFG_IMMR.
2895 Configuring the Linux kernel:
2896 -----------------------------
2898 No specific requirements for U-Boot. Make sure you have some root
2899 device (initial ramdisk, NFS) for your target system.
2902 Building a Linux Image:
2903 -----------------------
2905 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2906 not used. If you use recent kernel source, a new build target
2907 "uImage" will exist which automatically builds an image usable by
2908 U-Boot. Most older kernels also have support for a "pImage" target,
2909 which was introduced for our predecessor project PPCBoot and uses a
2910 100% compatible format.
2919 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2920 encapsulate a compressed Linux kernel image with header information,
2921 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2923 * build a standard "vmlinux" kernel image (in ELF binary format):
2925 * convert the kernel into a raw binary image:
2927 ${CROSS_COMPILE}-objcopy -O binary \
2928 -R .note -R .comment \
2929 -S vmlinux linux.bin
2931 * compress the binary image:
2935 * package compressed binary image for U-Boot:
2937 mkimage -A ppc -O linux -T kernel -C gzip \
2938 -a 0 -e 0 -n "Linux Kernel Image" \
2939 -d linux.bin.gz uImage
2942 The "mkimage" tool can also be used to create ramdisk images for use
2943 with U-Boot, either separated from the Linux kernel image, or
2944 combined into one file. "mkimage" encapsulates the images with a 64
2945 byte header containing information about target architecture,
2946 operating system, image type, compression method, entry points, time
2947 stamp, CRC32 checksums, etc.
2949 "mkimage" can be called in two ways: to verify existing images and
2950 print the header information, or to build new images.
2952 In the first form (with "-l" option) mkimage lists the information
2953 contained in the header of an existing U-Boot image; this includes
2954 checksum verification:
2956 tools/mkimage -l image
2957 -l ==> list image header information
2959 The second form (with "-d" option) is used to build a U-Boot image
2960 from a "data file" which is used as image payload:
2962 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2963 -n name -d data_file image
2964 -A ==> set architecture to 'arch'
2965 -O ==> set operating system to 'os'
2966 -T ==> set image type to 'type'
2967 -C ==> set compression type 'comp'
2968 -a ==> set load address to 'addr' (hex)
2969 -e ==> set entry point to 'ep' (hex)
2970 -n ==> set image name to 'name'
2971 -d ==> use image data from 'datafile'
2973 Right now, all Linux kernels for PowerPC systems use the same load
2974 address (0x00000000), but the entry point address depends on the
2977 - 2.2.x kernels have the entry point at 0x0000000C,
2978 - 2.3.x and later kernels have the entry point at 0x00000000.
2980 So a typical call to build a U-Boot image would read:
2982 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2983 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2984 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2985 > examples/uImage.TQM850L
2986 Image Name: 2.4.4 kernel for TQM850L
2987 Created: Wed Jul 19 02:34:59 2000
2988 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2989 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2990 Load Address: 0x00000000
2991 Entry Point: 0x00000000
2993 To verify the contents of the image (or check for corruption):
2995 -> tools/mkimage -l examples/uImage.TQM850L
2996 Image Name: 2.4.4 kernel for TQM850L
2997 Created: Wed Jul 19 02:34:59 2000
2998 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2999 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3000 Load Address: 0x00000000
3001 Entry Point: 0x00000000
3003 NOTE: for embedded systems where boot time is critical you can trade
3004 speed for memory and install an UNCOMPRESSED image instead: this
3005 needs more space in Flash, but boots much faster since it does not
3006 need to be uncompressed:
3008 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3009 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3010 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3011 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3012 > examples/uImage.TQM850L-uncompressed
3013 Image Name: 2.4.4 kernel for TQM850L
3014 Created: Wed Jul 19 02:34:59 2000
3015 Image Type: PowerPC Linux Kernel Image (uncompressed)
3016 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3017 Load Address: 0x00000000
3018 Entry Point: 0x00000000
3021 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3022 when your kernel is intended to use an initial ramdisk:
3024 -> tools/mkimage -n 'Simple Ramdisk Image' \
3025 > -A ppc -O linux -T ramdisk -C gzip \
3026 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3027 Image Name: Simple Ramdisk Image
3028 Created: Wed Jan 12 14:01:50 2000
3029 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3030 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3031 Load Address: 0x00000000
3032 Entry Point: 0x00000000
3035 Installing a Linux Image:
3036 -------------------------
3038 To downloading a U-Boot image over the serial (console) interface,
3039 you must convert the image to S-Record format:
3041 objcopy -I binary -O srec examples/image examples/image.srec
3043 The 'objcopy' does not understand the information in the U-Boot
3044 image header, so the resulting S-Record file will be relative to
3045 address 0x00000000. To load it to a given address, you need to
3046 specify the target address as 'offset' parameter with the 'loads'
3049 Example: install the image to address 0x40100000 (which on the
3050 TQM8xxL is in the first Flash bank):
3052 => erase 40100000 401FFFFF
3058 ## Ready for S-Record download ...
3059 ~>examples/image.srec
3060 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3062 15989 15990 15991 15992
3063 [file transfer complete]
3065 ## Start Addr = 0x00000000
3068 You can check the success of the download using the 'iminfo' command;
3069 this includes a checksum verification so you can be sure no data
3070 corruption happened:
3074 ## Checking Image at 40100000 ...
3075 Image Name: 2.2.13 for initrd on TQM850L
3076 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3077 Data Size: 335725 Bytes = 327 kB = 0 MB
3078 Load Address: 00000000
3079 Entry Point: 0000000c
3080 Verifying Checksum ... OK
3086 The "bootm" command is used to boot an application that is stored in
3087 memory (RAM or Flash). In case of a Linux kernel image, the contents
3088 of the "bootargs" environment variable is passed to the kernel as
3089 parameters. You can check and modify this variable using the
3090 "printenv" and "setenv" commands:
3093 => printenv bootargs
3094 bootargs=root=/dev/ram
3096 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3098 => printenv bootargs
3099 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3102 ## Booting Linux kernel at 40020000 ...
3103 Image Name: 2.2.13 for NFS on TQM850L
3104 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3105 Data Size: 381681 Bytes = 372 kB = 0 MB
3106 Load Address: 00000000
3107 Entry Point: 0000000c
3108 Verifying Checksum ... OK
3109 Uncompressing Kernel Image ... OK
3110 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
3111 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3112 time_init: decrementer frequency = 187500000/60
3113 Calibrating delay loop... 49.77 BogoMIPS
3114 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3117 If you want to boot a Linux kernel with initial ram disk, you pass
3118 the memory addresses of both the kernel and the initrd image (PPBCOOT
3119 format!) to the "bootm" command:
3121 => imi 40100000 40200000
3123 ## Checking Image at 40100000 ...
3124 Image Name: 2.2.13 for initrd on TQM850L
3125 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3126 Data Size: 335725 Bytes = 327 kB = 0 MB
3127 Load Address: 00000000
3128 Entry Point: 0000000c
3129 Verifying Checksum ... OK
3131 ## Checking Image at 40200000 ...
3132 Image Name: Simple Ramdisk Image
3133 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3134 Data Size: 566530 Bytes = 553 kB = 0 MB
3135 Load Address: 00000000
3136 Entry Point: 00000000
3137 Verifying Checksum ... OK
3139 => bootm 40100000 40200000
3140 ## Booting Linux kernel at 40100000 ...
3141 Image Name: 2.2.13 for initrd on TQM850L
3142 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3143 Data Size: 335725 Bytes = 327 kB = 0 MB
3144 Load Address: 00000000
3145 Entry Point: 0000000c
3146 Verifying Checksum ... OK
3147 Uncompressing Kernel Image ... OK
3148 ## Loading RAMDisk Image at 40200000 ...
3149 Image Name: Simple Ramdisk Image
3150 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3151 Data Size: 566530 Bytes = 553 kB = 0 MB
3152 Load Address: 00000000
3153 Entry Point: 00000000
3154 Verifying Checksum ... OK
3155 Loading Ramdisk ... OK
3156 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
3157 Boot arguments: root=/dev/ram
3158 time_init: decrementer frequency = 187500000/60
3159 Calibrating delay loop... 49.77 BogoMIPS
3161 RAMDISK: Compressed image found at block 0
3162 VFS: Mounted root (ext2 filesystem).
3166 Boot Linux and pass a flat device tree:
3169 First, U-Boot must be compiled with the appropriate defines. See the section
3170 titled "Linux Kernel Interface" above for a more in depth explanation. The
3171 following is an example of how to start a kernel and pass an updated
3177 oft=oftrees/mpc8540ads.dtb
3178 => tftp $oftaddr $oft
3179 Speed: 1000, full duplex
3181 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3182 Filename 'oftrees/mpc8540ads.dtb'.
3183 Load address: 0x300000
3186 Bytes transferred = 4106 (100a hex)
3187 => tftp $loadaddr $bootfile
3188 Speed: 1000, full duplex
3190 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3192 Load address: 0x200000
3193 Loading:############
3195 Bytes transferred = 1029407 (fb51f hex)
3200 => bootm $loadaddr - $oftaddr
3201 ## Booting image at 00200000 ...
3202 Image Name: Linux-2.6.17-dirty
3203 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3204 Data Size: 1029343 Bytes = 1005.2 kB
3205 Load Address: 00000000
3206 Entry Point: 00000000
3207 Verifying Checksum ... OK
3208 Uncompressing Kernel Image ... OK
3209 Booting using flat device tree at 0x300000
3210 Using MPC85xx ADS machine description
3211 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3215 More About U-Boot Image Types:
3216 ------------------------------
3218 U-Boot supports the following image types:
3220 "Standalone Programs" are directly runnable in the environment
3221 provided by U-Boot; it is expected that (if they behave
3222 well) you can continue to work in U-Boot after return from
3223 the Standalone Program.
3224 "OS Kernel Images" are usually images of some Embedded OS which
3225 will take over control completely. Usually these programs
3226 will install their own set of exception handlers, device
3227 drivers, set up the MMU, etc. - this means, that you cannot
3228 expect to re-enter U-Boot except by resetting the CPU.
3229 "RAMDisk Images" are more or less just data blocks, and their
3230 parameters (address, size) are passed to an OS kernel that is
3232 "Multi-File Images" contain several images, typically an OS
3233 (Linux) kernel image and one or more data images like
3234 RAMDisks. This construct is useful for instance when you want
3235 to boot over the network using BOOTP etc., where the boot
3236 server provides just a single image file, but you want to get
3237 for instance an OS kernel and a RAMDisk image.
3239 "Multi-File Images" start with a list of image sizes, each
3240 image size (in bytes) specified by an "uint32_t" in network
3241 byte order. This list is terminated by an "(uint32_t)0".
3242 Immediately after the terminating 0 follow the images, one by
3243 one, all aligned on "uint32_t" boundaries (size rounded up to
3244 a multiple of 4 bytes).
3246 "Firmware Images" are binary images containing firmware (like
3247 U-Boot or FPGA images) which usually will be programmed to
3250 "Script files" are command sequences that will be executed by
3251 U-Boot's command interpreter; this feature is especially
3252 useful when you configure U-Boot to use a real shell (hush)
3253 as command interpreter.
3259 One of the features of U-Boot is that you can dynamically load and
3260 run "standalone" applications, which can use some resources of
3261 U-Boot like console I/O functions or interrupt services.
3263 Two simple examples are included with the sources:
3268 'examples/hello_world.c' contains a small "Hello World" Demo
3269 application; it is automatically compiled when you build U-Boot.
3270 It's configured to run at address 0x00040004, so you can play with it
3274 ## Ready for S-Record download ...
3275 ~>examples/hello_world.srec
3276 1 2 3 4 5 6 7 8 9 10 11 ...
3277 [file transfer complete]
3279 ## Start Addr = 0x00040004
3281 => go 40004 Hello World! This is a test.
3282 ## Starting application at 0x00040004 ...
3293 Hit any key to exit ...
3295 ## Application terminated, rc = 0x0
3297 Another example, which demonstrates how to register a CPM interrupt
3298 handler with the U-Boot code, can be found in 'examples/timer.c'.
3299 Here, a CPM timer is set up to generate an interrupt every second.
3300 The interrupt service routine is trivial, just printing a '.'
3301 character, but this is just a demo program. The application can be
3302 controlled by the following keys:
3304 ? - print current values og the CPM Timer registers
3305 b - enable interrupts and start timer
3306 e - stop timer and disable interrupts
3307 q - quit application
3310 ## Ready for S-Record download ...
3311 ~>examples/timer.srec
3312 1 2 3 4 5 6 7 8 9 10 11 ...
3313 [file transfer complete]
3315 ## Start Addr = 0x00040004
3318 ## Starting application at 0x00040004 ...
3321 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3324 [q, b, e, ?] Set interval 1000000 us
3327 [q, b, e, ?] ........
3328 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3331 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3334 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3337 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3339 [q, b, e, ?] ...Stopping timer
3341 [q, b, e, ?] ## Application terminated, rc = 0x0
3347 Over time, many people have reported problems when trying to use the
3348 "minicom" terminal emulation program for serial download. I (wd)
3349 consider minicom to be broken, and recommend not to use it. Under
3350 Unix, I recommend to use C-Kermit for general purpose use (and
3351 especially for kermit binary protocol download ("loadb" command), and
3352 use "cu" for S-Record download ("loads" command).
3354 Nevertheless, if you absolutely want to use it try adding this
3355 configuration to your "File transfer protocols" section:
3357 Name Program Name U/D FullScr IO-Red. Multi
3358 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3359 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3365 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3366 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3368 Building requires a cross environment; it is known to work on
3369 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3370 need gmake since the Makefiles are not compatible with BSD make).
3371 Note that the cross-powerpc package does not install include files;
3372 attempting to build U-Boot will fail because <machine/ansi.h> is
3373 missing. This file has to be installed and patched manually:
3375 # cd /usr/pkg/cross/powerpc-netbsd/include
3377 # ln -s powerpc machine
3378 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3379 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3381 Native builds *don't* work due to incompatibilities between native
3382 and U-Boot include files.
3384 Booting assumes that (the first part of) the image booted is a
3385 stage-2 loader which in turn loads and then invokes the kernel
3386 proper. Loader sources will eventually appear in the NetBSD source
3387 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3388 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3391 Implementation Internals:
3392 =========================
3394 The following is not intended to be a complete description of every
3395 implementation detail. However, it should help to understand the
3396 inner workings of U-Boot and make it easier to port it to custom
3400 Initial Stack, Global Data:
3401 ---------------------------
3403 The implementation of U-Boot is complicated by the fact that U-Boot
3404 starts running out of ROM (flash memory), usually without access to
3405 system RAM (because the memory controller is not initialized yet).
3406 This means that we don't have writable Data or BSS segments, and BSS
3407 is not initialized as zero. To be able to get a C environment working
3408 at all, we have to allocate at least a minimal stack. Implementation
3409 options for this are defined and restricted by the CPU used: Some CPU
3410 models provide on-chip memory (like the IMMR area on MPC8xx and
3411 MPC826x processors), on others (parts of) the data cache can be
3412 locked as (mis-) used as memory, etc.
3414 Chris Hallinan posted a good summary of these issues to the
3415 u-boot-users mailing list:
3417 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3418 From: "Chris Hallinan" <clh@net1plus.com>
3419 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3422 Correct me if I'm wrong, folks, but the way I understand it
3423 is this: Using DCACHE as initial RAM for Stack, etc, does not
3424 require any physical RAM backing up the cache. The cleverness
3425 is that the cache is being used as a temporary supply of
3426 necessary storage before the SDRAM controller is setup. It's
3427 beyond the scope of this list to expain the details, but you
3428 can see how this works by studying the cache architecture and
3429 operation in the architecture and processor-specific manuals.
3431 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3432 is another option for the system designer to use as an
3433 initial stack/ram area prior to SDRAM being available. Either
3434 option should work for you. Using CS 4 should be fine if your
3435 board designers haven't used it for something that would
3436 cause you grief during the initial boot! It is frequently not
3439 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3440 with your processor/board/system design. The default value
3441 you will find in any recent u-boot distribution in
3442 walnut.h should work for you. I'd set it to a value larger
3443 than your SDRAM module. If you have a 64MB SDRAM module, set
3444 it above 400_0000. Just make sure your board has no resources
3445 that are supposed to respond to that address! That code in
3446 start.S has been around a while and should work as is when
3447 you get the config right.
3452 It is essential to remember this, since it has some impact on the C
3453 code for the initialization procedures:
3455 * Initialized global data (data segment) is read-only. Do not attempt
3458 * Do not use any unitialized global data (or implicitely initialized
3459 as zero data - BSS segment) at all - this is undefined, initiali-
3460 zation is performed later (when relocating to RAM).
3462 * Stack space is very limited. Avoid big data buffers or things like
3465 Having only the stack as writable memory limits means we cannot use
3466 normal global data to share information beween the code. But it
3467 turned out that the implementation of U-Boot can be greatly
3468 simplified by making a global data structure (gd_t) available to all
3469 functions. We could pass a pointer to this data as argument to _all_
3470 functions, but this would bloat the code. Instead we use a feature of
3471 the GCC compiler (Global Register Variables) to share the data: we
3472 place a pointer (gd) to the global data into a register which we
3473 reserve for this purpose.
3475 When choosing a register for such a purpose we are restricted by the
3476 relevant (E)ABI specifications for the current architecture, and by
3477 GCC's implementation.
3479 For PowerPC, the following registers have specific use:
3482 R3-R4: parameter passing and return values
3483 R5-R10: parameter passing
3484 R13: small data area pointer
3488 (U-Boot also uses R14 as internal GOT pointer.)
3490 ==> U-Boot will use R29 to hold a pointer to the global data
3492 Note: on PPC, we could use a static initializer (since the
3493 address of the global data structure is known at compile time),
3494 but it turned out that reserving a register results in somewhat
3495 smaller code - although the code savings are not that big (on
3496 average for all boards 752 bytes for the whole U-Boot image,
3497 624 text + 127 data).
3499 On ARM, the following registers are used:
3501 R0: function argument word/integer result
3502 R1-R3: function argument word
3504 R10: stack limit (used only if stack checking if enabled)
3505 R11: argument (frame) pointer
3506 R12: temporary workspace
3509 R15: program counter
3511 ==> U-Boot will use R8 to hold a pointer to the global data
3513 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3514 or current versions of GCC may "optimize" the code too much.
3519 U-Boot runs in system state and uses physical addresses, i.e. the
3520 MMU is not used either for address mapping nor for memory protection.
3522 The available memory is mapped to fixed addresses using the memory
3523 controller. In this process, a contiguous block is formed for each
3524 memory type (Flash, SDRAM, SRAM), even when it consists of several
3525 physical memory banks.
3527 U-Boot is installed in the first 128 kB of the first Flash bank (on
3528 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3529 booting and sizing and initializing DRAM, the code relocates itself
3530 to the upper end of DRAM. Immediately below the U-Boot code some
3531 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3532 configuration setting]. Below that, a structure with global Board
3533 Info data is placed, followed by the stack (growing downward).
3535 Additionally, some exception handler code is copied to the low 8 kB
3536 of DRAM (0x00000000 ... 0x00001FFF).
3538 So a typical memory configuration with 16 MB of DRAM could look like
3541 0x0000 0000 Exception Vector code
3544 0x0000 2000 Free for Application Use
3550 0x00FB FF20 Monitor Stack (Growing downward)
3551 0x00FB FFAC Board Info Data and permanent copy of global data
3552 0x00FC 0000 Malloc Arena
3555 0x00FE 0000 RAM Copy of Monitor Code
3556 ... eventually: LCD or video framebuffer
3557 ... eventually: pRAM (Protected RAM - unchanged by reset)
3558 0x00FF FFFF [End of RAM]
3561 System Initialization:
3562 ----------------------
3564 In the reset configuration, U-Boot starts at the reset entry point
3565 (on most PowerPC systens at address 0x00000100). Because of the reset
3566 configuration for CS0# this is a mirror of the onboard Flash memory.
3567 To be able to re-map memory U-Boot then jumps to its link address.
3568 To be able to implement the initialization code in C, a (small!)
3569 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3570 which provide such a feature like MPC8xx or MPC8260), or in a locked
3571 part of the data cache. After that, U-Boot initializes the CPU core,
3572 the caches and the SIU.
3574 Next, all (potentially) available memory banks are mapped using a
3575 preliminary mapping. For example, we put them on 512 MB boundaries
3576 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3577 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3578 programmed for SDRAM access. Using the temporary configuration, a
3579 simple memory test is run that determines the size of the SDRAM
3582 When there is more than one SDRAM bank, and the banks are of
3583 different size, the largest is mapped first. For equal size, the first
3584 bank (CS2#) is mapped first. The first mapping is always for address
3585 0x00000000, with any additional banks following immediately to create
3586 contiguous memory starting from 0.
3588 Then, the monitor installs itself at the upper end of the SDRAM area
3589 and allocates memory for use by malloc() and for the global Board
3590 Info data; also, the exception vector code is copied to the low RAM
3591 pages, and the final stack is set up.
3593 Only after this relocation will you have a "normal" C environment;
3594 until that you are restricted in several ways, mostly because you are
3595 running from ROM, and because the code will have to be relocated to a
3599 U-Boot Porting Guide:
3600 ----------------------
3602 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3606 int main (int argc, char *argv[])
3608 sighandler_t no_more_time;
3610 signal (SIGALRM, no_more_time);
3611 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3613 if (available_money > available_manpower) {
3614 pay consultant to port U-Boot;
3618 Download latest U-Boot source;
3620 Subscribe to u-boot-users mailing list;
3623 email ("Hi, I am new to U-Boot, how do I get started?");
3627 Read the README file in the top level directory;
3628 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3629 Read the source, Luke;
3632 if (available_money > toLocalCurrency ($2500)) {
3635 Add a lot of aggravation and time;
3638 Create your own board support subdirectory;
3640 Create your own board config file;
3644 Add / modify source code;
3648 email ("Hi, I am having problems...");
3650 Send patch file to Wolfgang;
3655 void no_more_time (int sig)
3664 All contributions to U-Boot should conform to the Linux kernel
3665 coding style; see the file "Documentation/CodingStyle" and the script
3666 "scripts/Lindent" in your Linux kernel source directory. In sources
3667 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3668 spaces before parameters to function calls) is actually used.
3670 Source files originating from a different project (for example the
3671 MTD subsystem) are generally exempt from these guidelines and are not
3672 reformated to ease subsequent migration to newer versions of those
3675 Please note that U-Boot is implemented in C (and to some small parts in
3676 Assembler); no C++ is used, so please do not use C++ style comments (//)
3679 Please also stick to the following formatting rules:
3680 - remove any trailing white space
3681 - use TAB characters for indentation, not spaces
3682 - make sure NOT to use DOS '\r\n' line feeds
3683 - do not add more than 2 empty lines to source files
3684 - do not add trailing empty lines to source files
3686 Submissions which do not conform to the standards may be returned
3687 with a request to reformat the changes.
3693 Since the number of patches for U-Boot is growing, we need to
3694 establish some rules. Submissions which do not conform to these rules
3695 may be rejected, even when they contain important and valuable stuff.
3697 Patches shall be sent to the u-boot-users mailing list.
3699 When you send a patch, please include the following information with
3702 * For bug fixes: a description of the bug and how your patch fixes
3703 this bug. Please try to include a way of demonstrating that the
3704 patch actually fixes something.
3706 * For new features: a description of the feature and your
3709 * A CHANGELOG entry as plaintext (separate from the patch)
3711 * For major contributions, your entry to the CREDITS file
3713 * When you add support for a new board, don't forget to add this
3714 board to the MAKEALL script, too.
3716 * If your patch adds new configuration options, don't forget to
3717 document these in the README file.
3719 * The patch itself. If you are accessing the CVS repository use "cvs
3720 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3721 version of diff does not support these options, then get the latest
3722 version of GNU diff.
3724 The current directory when running this command shall be the top
3725 level directory of the U-Boot source tree, or it's parent directory
3726 (i. e. please make sure that your patch includes sufficient
3727 directory information for the affected files).
3729 We accept patches as plain text, MIME attachments or as uuencoded
3732 * If one logical set of modifications affects or creates several
3733 files, all these changes shall be submitted in a SINGLE patch file.
3735 * Changesets that contain different, unrelated modifications shall be
3736 submitted as SEPARATE patches, one patch per changeset.
3741 * Before sending the patch, run the MAKEALL script on your patched
3742 source tree and make sure that no errors or warnings are reported
3743 for any of the boards.
3745 * Keep your modifications to the necessary minimum: A patch
3746 containing several unrelated changes or arbitrary reformats will be
3747 returned with a request to re-formatting / split it.
3749 * If you modify existing code, make sure that your new code does not
3750 add to the memory footprint of the code ;-) Small is beautiful!
3751 When adding new features, these should compile conditionally only
3752 (using #ifdef), and the resulting code with the new feature
3753 disabled must not need more memory than the old code without your
3756 * Remember that there is a size limit of 40 kB per message on the
3757 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob