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 - mips Files specific to MIPS CPUs
140 - mpc5xx Files specific to Freescale MPC5xx CPUs
141 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
142 - mpc8xx Files specific to Freescale MPC8xx CPUs
143 - mpc8220 Files specific to Freescale MPC8220 CPUs
144 - mpc824x Files specific to Freescale MPC824x CPUs
145 - mpc8260 Files specific to Freescale MPC8260 CPUs
146 - mpc85xx Files specific to Freescale MPC85xx CPUs
147 - nios Files specific to Altera NIOS CPUs
148 - nios2 Files specific to Altera Nios-II CPUs
149 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
150 - pxa Files specific to Intel XScale PXA CPUs
151 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
152 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
153 - disk Code for disk drive partition handling
154 - doc Documentation (don't expect too much)
155 - drivers Commonly used device drivers
156 - dtt Digital Thermometer and Thermostat drivers
157 - examples Example code for standalone applications, etc.
158 - include Header Files
159 - lib_arm Files generic to ARM architecture
160 - lib_avr32 Files generic to AVR32 architecture
161 - lib_generic Files generic to all architectures
162 - lib_i386 Files generic to i386 architecture
163 - lib_m68k Files generic to m68k architecture
164 - lib_mips Files generic to MIPS architecture
165 - lib_nios Files generic to NIOS architecture
166 - lib_ppc Files generic to PowerPC architecture
167 - libfdt Library files to support flattened device trees
168 - net Networking code
169 - post Power On Self Test
170 - rtc Real Time Clock drivers
171 - tools Tools to build S-Record or U-Boot images, etc.
173 Software Configuration:
174 =======================
176 Configuration is usually done using C preprocessor defines; the
177 rationale behind that is to avoid dead code whenever possible.
179 There are two classes of configuration variables:
181 * Configuration _OPTIONS_:
182 These are selectable by the user and have names beginning with
185 * Configuration _SETTINGS_:
186 These depend on the hardware etc. and should not be meddled with if
187 you don't know what you're doing; they have names beginning with
190 Later we will add a configuration tool - probably similar to or even
191 identical to what's used for the Linux kernel. Right now, we have to
192 do the configuration by hand, which means creating some symbolic
193 links and editing some configuration files. We use the TQM8xxL boards
197 Selection of Processor Architecture and Board Type:
198 ---------------------------------------------------
200 For all supported boards there are ready-to-use default
201 configurations available; just type "make <board_name>_config".
203 Example: For a TQM823L module type:
208 For the Cogent platform, you need to specify the cpu type as well;
209 e.g. "make cogent_mpc8xx_config". And also configure the cogent
210 directory according to the instructions in cogent/README.
213 Configuration Options:
214 ----------------------
216 Configuration depends on the combination of board and CPU type; all
217 such information is kept in a configuration file
218 "include/configs/<board_name>.h".
220 Example: For a TQM823L module, all configuration settings are in
221 "include/configs/TQM823L.h".
224 Many of the options are named exactly as the corresponding Linux
225 kernel configuration options. The intention is to make it easier to
226 build a config tool - later.
229 The following options need to be configured:
231 - CPU Type: Define exactly one of
235 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
238 or CONFIG_MPC824X, CONFIG_MPC8260
254 MicroBlaze based CPUs:
255 ----------------------
259 ----------------------
263 ----------------------
266 - Board Type: Define exactly one of
268 PowerPC based boards:
269 ---------------------
271 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
272 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
273 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
274 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
275 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
276 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
277 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
278 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
279 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
280 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
281 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
282 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
283 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
284 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
285 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
286 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
287 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
288 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
289 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
290 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
291 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
292 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
293 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
294 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
295 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
296 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
297 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
298 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
299 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
300 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
301 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
302 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
303 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
304 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
305 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
306 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
307 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
308 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
313 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
314 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
315 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
316 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
317 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
318 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
319 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
320 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
323 MicroBlaze based boards:
324 ------------------------
329 ------------------------
331 CONFIG_PCI5441 CONFIG_PK1C20
332 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
339 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
340 Define exactly one of
344 - CPU Module Type: (if CONFIG_COGENT is defined)
345 Define exactly one of
347 --- FIXME --- not tested yet:
348 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
349 CONFIG_CMA287_23, CONFIG_CMA287_50
351 - Motherboard Type: (if CONFIG_COGENT is defined)
352 Define exactly one of
353 CONFIG_CMA101, CONFIG_CMA102
355 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
356 Define one or more of
359 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
360 Define one or more of
361 CONFIG_LCD_HEARTBEAT - update a character position on
362 the lcd display every second with
365 - Board flavour: (if CONFIG_MPC8260ADS is defined)
368 CFG_8260ADS - original MPC8260ADS
369 CFG_8266ADS - MPC8266ADS
370 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
371 CFG_8272ADS - MPC8272ADS
373 - MPC824X Family Member (if CONFIG_MPC824X is defined)
374 Define exactly one of
375 CONFIG_MPC8240, CONFIG_MPC8245
377 - 8xx CPU Options: (if using an MPC8xx cpu)
378 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
379 get_gclk_freq() cannot work
380 e.g. if there is no 32KHz
381 reference PIT/RTC clock
382 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
385 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
388 CONFIG_8xx_CPUCLK_DEFAULT
389 See doc/README.MPC866
393 Define this to measure the actual CPU clock instead
394 of relying on the correctness of the configured
395 values. Mostly useful for board bringup to make sure
396 the PLL is locked at the intended frequency. Note
397 that this requires a (stable) reference clock (32 kHz
398 RTC clock or CFG_8XX_XIN)
400 - Intel Monahans options:
401 CFG_MONAHANS_RUN_MODE_OSC_RATIO
403 Defines the Monahans run mode to oscillator
404 ratio. Valid values are 8, 16, 24, 31. The core
405 frequency is this value multiplied by 13 MHz.
407 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
409 Defines the Monahans turbo mode to oscillator
410 ratio. Valid values are 1 (default if undefined) and
411 2. The core frequency as calculated above is multiplied
414 - Linux Kernel Interface:
417 U-Boot stores all clock information in Hz
418 internally. For binary compatibility with older Linux
419 kernels (which expect the clocks passed in the
420 bd_info data to be in MHz) the environment variable
421 "clocks_in_mhz" can be defined so that U-Boot
422 converts clock data to MHZ before passing it to the
424 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
425 "clocks_in_mhz=1" is automatically included in the
428 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
430 When transfering memsize parameter to linux, some versions
431 expect it to be in bytes, others in MB.
432 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
434 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
436 New kernel versions are expecting firmware settings to be
437 passed using flattened device trees (based on open firmware
441 * New libfdt-based support
442 * Adds the "fdt" command
443 * The bootm command does _not_ modify the fdt
446 * Deprecated, see CONFIG_OF_LIBFDT
447 * Original ft_build.c-based support
448 * Automatically modifies the dft as part of the bootm command
449 * The environment variable "disable_of", when set,
450 disables this functionality.
452 CONFIG_OF_FLAT_TREE_MAX_SIZE
454 The maximum size of the constructed OF tree.
456 OF_CPU - The proper name of the cpus node.
457 OF_SOC - The proper name of the soc node.
458 OF_TBCLK - The timebase frequency.
459 OF_STDOUT_PATH - The path to the console device
463 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
464 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
465 will have a copy of the bd_t. Space should be
466 pre-allocated in the dts for the bd_t.
468 CONFIG_OF_HAS_UBOOT_ENV
470 * CONFIG_OF_LIBFDT - enables the "fdt bd_t" command
471 * CONFIG_OF_FLAT_TREE - The resulting flat device tree
472 will have a copy of u-boot's environment variables
474 CONFIG_OF_BOARD_SETUP
476 Board code has addition modification that it wants to make
477 to the flat device tree before handing it off to the kernel
481 This define fills in the correct boot cpu in the boot
482 param header, the default value is zero if undefined.
487 Define this if you want support for Amba PrimeCell PL010 UARTs.
491 Define this if you want support for Amba PrimeCell PL011 UARTs.
495 If you have Amba PrimeCell PL011 UARTs, set this variable to
496 the clock speed of the UARTs.
500 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
501 define this to a list of base addresses for each (supported)
502 port. See e.g. include/configs/versatile.h
506 Depending on board, define exactly one serial port
507 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
508 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
509 console by defining CONFIG_8xx_CONS_NONE
511 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
512 port routines must be defined elsewhere
513 (i.e. serial_init(), serial_getc(), ...)
516 Enables console device for a color framebuffer. Needs following
517 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
518 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
520 VIDEO_HW_RECTFILL graphic chip supports
523 VIDEO_HW_BITBLT graphic chip supports
524 bit-blit (cf. smiLynxEM)
525 VIDEO_VISIBLE_COLS visible pixel columns
527 VIDEO_VISIBLE_ROWS visible pixel rows
528 VIDEO_PIXEL_SIZE bytes per pixel
529 VIDEO_DATA_FORMAT graphic data format
530 (0-5, cf. cfb_console.c)
531 VIDEO_FB_ADRS framebuffer address
532 VIDEO_KBD_INIT_FCT keyboard int fct
533 (i.e. i8042_kbd_init())
534 VIDEO_TSTC_FCT test char fct
536 VIDEO_GETC_FCT get char fct
538 CONFIG_CONSOLE_CURSOR cursor drawing on/off
539 (requires blink timer
541 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
542 CONFIG_CONSOLE_TIME display time/date info in
544 (requires CONFIG_CMD_DATE)
545 CONFIG_VIDEO_LOGO display Linux logo in
547 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
548 linux_logo.h for logo.
549 Requires CONFIG_VIDEO_LOGO
550 CONFIG_CONSOLE_EXTRA_INFO
551 addional board info beside
554 When CONFIG_CFB_CONSOLE is defined, video console is
555 default i/o. Serial console can be forced with
556 environment 'console=serial'.
558 When CONFIG_SILENT_CONSOLE is defined, all console
559 messages (by U-Boot and Linux!) can be silenced with
560 the "silent" environment variable. See
561 doc/README.silent for more information.
564 CONFIG_BAUDRATE - in bps
565 Select one of the baudrates listed in
566 CFG_BAUDRATE_TABLE, see below.
567 CFG_BRGCLK_PRESCALE, baudrate prescale
569 - Interrupt driven serial port input:
570 CONFIG_SERIAL_SOFTWARE_FIFO
573 Use an interrupt handler for receiving data on the
574 serial port. It also enables using hardware handshake
575 (RTS/CTS) and UART's built-in FIFO. Set the number of
576 bytes the interrupt driven input buffer should have.
578 Leave undefined to disable this feature, including
579 disable the buffer and hardware handshake.
581 - Console UART Number:
585 If defined internal UART1 (and not UART0) is used
586 as default U-Boot console.
588 - Boot Delay: CONFIG_BOOTDELAY - in seconds
589 Delay before automatically booting the default image;
590 set to -1 to disable autoboot.
592 See doc/README.autoboot for these options that
593 work with CONFIG_BOOTDELAY. None are required.
594 CONFIG_BOOT_RETRY_TIME
595 CONFIG_BOOT_RETRY_MIN
596 CONFIG_AUTOBOOT_KEYED
597 CONFIG_AUTOBOOT_PROMPT
598 CONFIG_AUTOBOOT_DELAY_STR
599 CONFIG_AUTOBOOT_STOP_STR
600 CONFIG_AUTOBOOT_DELAY_STR2
601 CONFIG_AUTOBOOT_STOP_STR2
602 CONFIG_ZERO_BOOTDELAY_CHECK
603 CONFIG_RESET_TO_RETRY
607 Only needed when CONFIG_BOOTDELAY is enabled;
608 define a command string that is automatically executed
609 when no character is read on the console interface
610 within "Boot Delay" after reset.
613 This can be used to pass arguments to the bootm
614 command. The value of CONFIG_BOOTARGS goes into the
615 environment value "bootargs".
617 CONFIG_RAMBOOT and CONFIG_NFSBOOT
618 The value of these goes into the environment as
619 "ramboot" and "nfsboot" respectively, and can be used
620 as a convenience, when switching between booting from
626 When this option is #defined, the existence of the
627 environment variable "preboot" will be checked
628 immediately before starting the CONFIG_BOOTDELAY
629 countdown and/or running the auto-boot command resp.
630 entering interactive mode.
632 This feature is especially useful when "preboot" is
633 automatically generated or modified. For an example
634 see the LWMON board specific code: here "preboot" is
635 modified when the user holds down a certain
636 combination of keys on the (special) keyboard when
639 - Serial Download Echo Mode:
641 If defined to 1, all characters received during a
642 serial download (using the "loads" command) are
643 echoed back. This might be needed by some terminal
644 emulations (like "cu"), but may as well just take
645 time on others. This setting #define's the initial
646 value of the "loads_echo" environment variable.
648 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
650 Select one of the baudrates listed in
651 CFG_BAUDRATE_TABLE, see below.
654 Monitor commands can be included or excluded
655 from the build by using the #include files
656 "config_cmd_all.h" and #undef'ing unwanted
657 commands, or using "config_cmd_default.h"
658 and augmenting with additional #define's
661 The default command configuration includes all commands
662 except those marked below with a "*".
664 CONFIG_CMD_ASKENV * ask for env variable
665 CONFIG_CMD_AUTOSCRIPT Autoscript Support
666 CONFIG_CMD_BDI bdinfo
667 CONFIG_CMD_BEDBUG * Include BedBug Debugger
668 CONFIG_CMD_BMP * BMP support
669 CONFIG_CMD_BSP * Board specific commands
670 CONFIG_CMD_BOOTD bootd
671 CONFIG_CMD_CACHE * icache, dcache
672 CONFIG_CMD_CONSOLE coninfo
673 CONFIG_CMD_DATE * support for RTC, date/time...
674 CONFIG_CMD_DHCP * DHCP support
675 CONFIG_CMD_DIAG * Diagnostics
676 CONFIG_CMD_DOC * Disk-On-Chip Support
677 CONFIG_CMD_DTT * Digital Therm and Thermostat
678 CONFIG_CMD_ECHO echo arguments
679 CONFIG_CMD_EEPROM * EEPROM read/write support
680 CONFIG_CMD_ELF * bootelf, bootvx
681 CONFIG_CMD_ENV saveenv
682 CONFIG_CMD_FDC * Floppy Disk Support
683 CONFIG_CMD_FAT * FAT partition support
684 CONFIG_CMD_FDOS * Dos diskette Support
685 CONFIG_CMD_FLASH flinfo, erase, protect
686 CONFIG_CMD_FPGA FPGA device initialization support
687 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
688 CONFIG_CMD_I2C * I2C serial bus support
689 CONFIG_CMD_IDE * IDE harddisk support
690 CONFIG_CMD_IMI iminfo
691 CONFIG_CMD_IMLS List all found images
692 CONFIG_CMD_IMMAP * IMMR dump support
693 CONFIG_CMD_IRQ * irqinfo
694 CONFIG_CMD_ITEST Integer/string test of 2 values
695 CONFIG_CMD_JFFS2 * JFFS2 Support
696 CONFIG_CMD_KGDB * kgdb
697 CONFIG_CMD_LOADB loadb
698 CONFIG_CMD_LOADS loads
699 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
701 CONFIG_CMD_MISC Misc functions like sleep etc
702 CONFIG_CMD_MMC * MMC memory mapped support
703 CONFIG_CMD_MII * MII utility commands
704 CONFIG_CMD_NAND * NAND support
705 CONFIG_CMD_NET bootp, tftpboot, rarpboot
706 CONFIG_CMD_PCI * pciinfo
707 CONFIG_CMD_PCMCIA * PCMCIA support
708 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
710 CONFIG_CMD_PORTIO * Port I/O
711 CONFIG_CMD_REGINFO * Register dump
712 CONFIG_CMD_RUN run command in env variable
713 CONFIG_CMD_SAVES * save S record dump
714 CONFIG_CMD_SCSI * SCSI Support
715 CONFIG_CMD_SDRAM * print SDRAM configuration information
716 (requires CONFIG_CMD_I2C)
717 CONFIG_CMD_SETGETDCR Support for DCR Register access
719 CONFIG_CMD_SPI * SPI serial bus support
720 CONFIG_CMD_USB * USB support
721 CONFIG_CMD_VFD * VFD support (TRAB)
722 CONFIG_CMD_BSP * Board SPecific functions
723 CONFIG_CMD_CDP * Cisco Discover Protocol support
724 CONFIG_CMD_FSL * Microblaze FSL support
727 EXAMPLE: If you want all functions except of network
728 support you can write:
730 #include "config_cmd_all.h"
731 #undef CONFIG_CMD_NET
734 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
736 Note: Don't enable the "icache" and "dcache" commands
737 (configuration option CONFIG_CMD_CACHE) unless you know
738 what you (and your U-Boot users) are doing. Data
739 cache cannot be enabled on systems like the 8xx or
740 8260 (where accesses to the IMMR region must be
741 uncached), and it cannot be disabled on all other
742 systems where we (mis-) use the data cache to hold an
743 initial stack and some data.
746 XXX - this list needs to get updated!
750 If this variable is defined, it enables watchdog
751 support. There must be support in the platform specific
752 code for a watchdog. For the 8xx and 8260 CPUs, the
753 SIU Watchdog feature is enabled in the SYPCR
757 CONFIG_VERSION_VARIABLE
758 If this variable is defined, an environment variable
759 named "ver" is created by U-Boot showing the U-Boot
760 version as printed by the "version" command.
761 This variable is readonly.
765 When CONFIG_CMD_DATE is selected, the type of the RTC
766 has to be selected, too. Define exactly one of the
769 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
770 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
771 CONFIG_RTC_MC146818 - use MC146818 RTC
772 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
773 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
774 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
775 CONFIG_RTC_DS164x - use Dallas DS164x RTC
776 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
778 Note that if the RTC uses I2C, then the I2C interface
779 must also be configured. See I2C Support, below.
783 When CONFIG_TIMESTAMP is selected, the timestamp
784 (date and time) of an image is printed by image
785 commands like bootm or iminfo. This option is
786 automatically enabled when you select CONFIG_CMD_DATE .
789 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
790 and/or CONFIG_ISO_PARTITION
792 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
793 CONFIG_CMD_SCSI) you must configure support for at least
794 one partition type as well.
797 CONFIG_IDE_RESET_ROUTINE - this is defined in several
798 board configurations files but used nowhere!
800 CONFIG_IDE_RESET - is this is defined, IDE Reset will
801 be performed by calling the function
802 ide_set_reset(int reset)
803 which has to be defined in a board specific file
808 Set this to enable ATAPI support.
813 Set this to enable support for disks larger than 137GB
814 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
815 Whithout these , LBA48 support uses 32bit variables and will 'only'
816 support disks up to 2.1TB.
819 When enabled, makes the IDE subsystem use 64bit sector addresses.
823 At the moment only there is only support for the
824 SYM53C8XX SCSI controller; define
825 CONFIG_SCSI_SYM53C8XX to enable it.
827 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
828 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
829 CFG_SCSI_MAX_LUN] can be adjusted to define the
830 maximum numbers of LUNs, SCSI ID's and target
832 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
834 - NETWORK Support (PCI):
836 Support for Intel 8254x gigabit chips.
839 Support for Intel 82557/82559/82559ER chips.
840 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
841 write routine for first time initialisation.
844 Support for Digital 2114x chips.
845 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
846 modem chip initialisation (KS8761/QS6611).
849 Support for National dp83815 chips.
852 Support for National dp8382[01] gigabit chips.
854 - NETWORK Support (other):
856 CONFIG_DRIVER_LAN91C96
857 Support for SMSC's LAN91C96 chips.
860 Define this to hold the physical address
861 of the LAN91C96's I/O space
863 CONFIG_LAN91C96_USE_32_BIT
864 Define this to enable 32 bit addressing
866 CONFIG_DRIVER_SMC91111
867 Support for SMSC's LAN91C111 chip
870 Define this to hold the physical address
871 of the device (I/O space)
873 CONFIG_SMC_USE_32_BIT
874 Define this if data bus is 32 bits
876 CONFIG_SMC_USE_IOFUNCS
877 Define this to use i/o functions instead of macros
878 (some hardware wont work with macros)
881 At the moment only the UHCI host controller is
882 supported (PIP405, MIP405, MPC5200); define
883 CONFIG_USB_UHCI to enable it.
884 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
885 and define CONFIG_USB_STORAGE to enable the USB
888 Supported are USB Keyboards and USB Floppy drives
890 MPC5200 USB requires additional defines:
892 for 528 MHz Clock: 0x0001bbbb
894 for differential drivers: 0x00001000
895 for single ended drivers: 0x00005000
899 The MMC controller on the Intel PXA is supported. To
900 enable this define CONFIG_MMC. The MMC can be
901 accessed from the boot prompt by mapping the device
902 to physical memory similar to flash. Command line is
903 enabled with CONFIG_CMD_MMC. The MMC driver also works with
904 the FAT fs. This is enabled with CONFIG_CMD_FAT.
906 - Journaling Flash filesystem support:
907 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
908 CONFIG_JFFS2_NAND_DEV
909 Define these for a default partition on a NAND device
911 CFG_JFFS2_FIRST_SECTOR,
912 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
913 Define these for a default partition on a NOR device
916 Define this to create an own partition. You have to provide a
917 function struct part_info* jffs2_part_info(int part_num)
919 If you define only one JFFS2 partition you may also want to
920 #define CFG_JFFS_SINGLE_PART 1
921 to disable the command chpart. This is the default when you
922 have not defined a custom partition
927 Define this to enable standard (PC-Style) keyboard
931 Standard PC keyboard driver with US (is default) and
932 GERMAN key layout (switch via environment 'keymap=de') support.
933 Export function i8042_kbd_init, i8042_tstc and i8042_getc
934 for cfb_console. Supports cursor blinking.
939 Define this to enable video support (for output to
944 Enable Chips & Technologies 69000 Video chip
946 CONFIG_VIDEO_SMI_LYNXEM
947 Enable Silicon Motion SMI 712/710/810 Video chip. The
948 video output is selected via environment 'videoout'
949 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
952 For the CT69000 and SMI_LYNXEM drivers, videomode is
953 selected via environment 'videomode'. Two diferent ways
955 - "videomode=num" 'num' is a standard LiLo mode numbers.
956 Following standard modes are supported (* is default):
958 Colors 640x480 800x600 1024x768 1152x864 1280x1024
959 -------------+---------------------------------------------
960 8 bits | 0x301* 0x303 0x305 0x161 0x307
961 15 bits | 0x310 0x313 0x316 0x162 0x319
962 16 bits | 0x311 0x314 0x317 0x163 0x31A
963 24 bits | 0x312 0x315 0x318 ? 0x31B
964 -------------+---------------------------------------------
965 (i.e. setenv videomode 317; saveenv; reset;)
967 - "videomode=bootargs" all the video parameters are parsed
968 from the bootargs. (See drivers/videomodes.c)
971 CONFIG_VIDEO_SED13806
972 Enable Epson SED13806 driver. This driver supports 8bpp
973 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
974 or CONFIG_VIDEO_SED13806_16BPP
979 Define this to enable a custom keyboard support.
980 This simply calls drv_keyboard_init() which must be
981 defined in your board-specific files.
982 The only board using this so far is RBC823.
984 - LCD Support: CONFIG_LCD
986 Define this to enable LCD support (for output to LCD
987 display); also select one of the supported displays
988 by defining one of these:
990 CONFIG_NEC_NL6448AC33:
992 NEC NL6448AC33-18. Active, color, single scan.
994 CONFIG_NEC_NL6448BC20
996 NEC NL6448BC20-08. 6.5", 640x480.
997 Active, color, single scan.
999 CONFIG_NEC_NL6448BC33_54
1001 NEC NL6448BC33-54. 10.4", 640x480.
1002 Active, color, single scan.
1006 Sharp 320x240. Active, color, single scan.
1007 It isn't 16x9, and I am not sure what it is.
1009 CONFIG_SHARP_LQ64D341
1011 Sharp LQ64D341 display, 640x480.
1012 Active, color, single scan.
1016 HLD1045 display, 640x480.
1017 Active, color, single scan.
1021 Optrex CBL50840-2 NF-FW 99 22 M5
1023 Hitachi LMG6912RPFC-00T
1027 320x240. Black & white.
1029 Normally display is black on white background; define
1030 CFG_WHITE_ON_BLACK to get it inverted.
1032 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1034 If this option is set, the environment is checked for
1035 a variable "splashimage". If found, the usual display
1036 of logo, copyright and system information on the LCD
1037 is suppressed and the BMP image at the address
1038 specified in "splashimage" is loaded instead. The
1039 console is redirected to the "nulldev", too. This
1040 allows for a "silent" boot where a splash screen is
1041 loaded very quickly after power-on.
1043 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1045 If this option is set, additionally to standard BMP
1046 images, gzipped BMP images can be displayed via the
1047 splashscreen support or the bmp command.
1049 - Compression support:
1052 If this option is set, support for bzip2 compressed
1053 images is included. If not, only uncompressed and gzip
1054 compressed images are supported.
1056 NOTE: the bzip2 algorithm requires a lot of RAM, so
1057 the malloc area (as defined by CFG_MALLOC_LEN) should
1063 The address of PHY on MII bus.
1065 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1067 The clock frequency of the MII bus
1071 If this option is set, support for speed/duplex
1072 detection of Gigabit PHY is included.
1074 CONFIG_PHY_RESET_DELAY
1076 Some PHY like Intel LXT971A need extra delay after
1077 reset before any MII register access is possible.
1078 For such PHY, set this option to the usec delay
1079 required. (minimum 300usec for LXT971A)
1081 CONFIG_PHY_CMD_DELAY (ppc4xx)
1083 Some PHY like Intel LXT971A need extra delay after
1084 command issued before MII status register can be read
1091 Define a default value for ethernet address to use
1092 for the respective ethernet interface, in case this
1093 is not determined automatically.
1098 Define a default value for the IP address to use for
1099 the default ethernet interface, in case this is not
1100 determined through e.g. bootp.
1102 - Server IP address:
1105 Defines a default value for theIP address of a TFTP
1106 server to contact when using the "tftboot" command.
1108 - BOOTP Recovery Mode:
1109 CONFIG_BOOTP_RANDOM_DELAY
1111 If you have many targets in a network that try to
1112 boot using BOOTP, you may want to avoid that all
1113 systems send out BOOTP requests at precisely the same
1114 moment (which would happen for instance at recovery
1115 from a power failure, when all systems will try to
1116 boot, thus flooding the BOOTP server. Defining
1117 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1118 inserted before sending out BOOTP requests. The
1119 following delays are insterted then:
1121 1st BOOTP request: delay 0 ... 1 sec
1122 2nd BOOTP request: delay 0 ... 2 sec
1123 3rd BOOTP request: delay 0 ... 4 sec
1125 BOOTP requests: delay 0 ... 8 sec
1127 - DHCP Advanced Options:
1128 You can fine tune the DHCP functionality by defining
1129 CONFIG_BOOTP_* symbols:
1131 CONFIG_BOOTP_SUBNETMASK
1132 CONFIG_BOOTP_GATEWAY
1133 CONFIG_BOOTP_HOSTNAME
1134 CONFIG_BOOTP_NISDOMAIN
1135 CONFIG_BOOTP_BOOTPATH
1136 CONFIG_BOOTP_BOOTFILESIZE
1139 CONFIG_BOOTP_SEND_HOSTNAME
1140 CONFIG_BOOTP_NTPSERVER
1141 CONFIG_BOOTP_TIMEOFFSET
1142 CONFIG_BOOTP_VENDOREX
1144 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1145 serverip from a DHCP server, it is possible that more
1146 than one DNS serverip is offered to the client.
1147 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1148 serverip will be stored in the additional environment
1149 variable "dnsip2". The first DNS serverip is always
1150 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1153 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1154 to do a dynamic update of a DNS server. To do this, they
1155 need the hostname of the DHCP requester.
1156 If CONFIG_BOOP_SEND_HOSTNAME is defined, the content
1157 of the "hostname" environment variable is passed as
1158 option 12 to the DHCP server.
1161 CONFIG_CDP_DEVICE_ID
1163 The device id used in CDP trigger frames.
1165 CONFIG_CDP_DEVICE_ID_PREFIX
1167 A two character string which is prefixed to the MAC address
1172 A printf format string which contains the ascii name of
1173 the port. Normally is set to "eth%d" which sets
1174 eth0 for the first ethernet, eth1 for the second etc.
1176 CONFIG_CDP_CAPABILITIES
1178 A 32bit integer which indicates the device capabilities;
1179 0x00000010 for a normal host which does not forwards.
1183 An ascii string containing the version of the software.
1187 An ascii string containing the name of the platform.
1191 A 32bit integer sent on the trigger.
1193 CONFIG_CDP_POWER_CONSUMPTION
1195 A 16bit integer containing the power consumption of the
1196 device in .1 of milliwatts.
1198 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1200 A byte containing the id of the VLAN.
1202 - Status LED: CONFIG_STATUS_LED
1204 Several configurations allow to display the current
1205 status using a LED. For instance, the LED will blink
1206 fast while running U-Boot code, stop blinking as
1207 soon as a reply to a BOOTP request was received, and
1208 start blinking slow once the Linux kernel is running
1209 (supported by a status LED driver in the Linux
1210 kernel). Defining CONFIG_STATUS_LED enables this
1213 - CAN Support: CONFIG_CAN_DRIVER
1215 Defining CONFIG_CAN_DRIVER enables CAN driver support
1216 on those systems that support this (optional)
1217 feature, like the TQM8xxL modules.
1219 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1221 These enable I2C serial bus commands. Defining either of
1222 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1223 include the appropriate I2C driver for the selected cpu.
1225 This will allow you to use i2c commands at the u-boot
1226 command line (as long as you set CONFIG_CMD_I2C in
1227 CONFIG_COMMANDS) and communicate with i2c based realtime
1228 clock chips. See common/cmd_i2c.c for a description of the
1229 command line interface.
1231 CONFIG_I2C_CMD_TREE is a recommended option that places
1232 all I2C commands under a single 'i2c' root command. The
1233 older 'imm', 'imd', 'iprobe' etc. commands are considered
1234 deprecated and may disappear in the future.
1236 CONFIG_HARD_I2C selects a hardware I2C controller.
1238 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1239 bit-banging) driver instead of CPM or similar hardware
1242 There are several other quantities that must also be
1243 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1245 In both cases you will need to define CFG_I2C_SPEED
1246 to be the frequency (in Hz) at which you wish your i2c bus
1247 to run and CFG_I2C_SLAVE to be the address of this node (ie
1248 the cpu's i2c node address).
1250 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1251 sets the cpu up as a master node and so its address should
1252 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1253 p.16-473). So, set CFG_I2C_SLAVE to 0.
1255 That's all that's required for CONFIG_HARD_I2C.
1257 If you use the software i2c interface (CONFIG_SOFT_I2C)
1258 then the following macros need to be defined (examples are
1259 from include/configs/lwmon.h):
1263 (Optional). Any commands necessary to enable the I2C
1264 controller or configure ports.
1266 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1270 (Only for MPC8260 CPU). The I/O port to use (the code
1271 assumes both bits are on the same port). Valid values
1272 are 0..3 for ports A..D.
1276 The code necessary to make the I2C data line active
1277 (driven). If the data line is open collector, this
1280 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1284 The code necessary to make the I2C data line tri-stated
1285 (inactive). If the data line is open collector, this
1288 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1292 Code that returns TRUE if the I2C data line is high,
1295 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1299 If <bit> is TRUE, sets the I2C data line high. If it
1300 is FALSE, it clears it (low).
1302 eg: #define I2C_SDA(bit) \
1303 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1304 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1308 If <bit> is TRUE, sets the I2C clock line high. If it
1309 is FALSE, it clears it (low).
1311 eg: #define I2C_SCL(bit) \
1312 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1313 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1317 This delay is invoked four times per clock cycle so this
1318 controls the rate of data transfer. The data rate thus
1319 is 1 / (I2C_DELAY * 4). Often defined to be something
1322 #define I2C_DELAY udelay(2)
1326 When a board is reset during an i2c bus transfer
1327 chips might think that the current transfer is still
1328 in progress. On some boards it is possible to access
1329 the i2c SCLK line directly, either by using the
1330 processor pin as a GPIO or by having a second pin
1331 connected to the bus. If this option is defined a
1332 custom i2c_init_board() routine in boards/xxx/board.c
1333 is run early in the boot sequence.
1335 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1337 This option enables configuration of bi_iic_fast[] flags
1338 in u-boot bd_info structure based on u-boot environment
1339 variable "i2cfast". (see also i2cfast)
1341 CONFIG_I2C_MULTI_BUS
1343 This option allows the use of multiple I2C buses, each of which
1344 must have a controller. At any point in time, only one bus is
1345 active. To switch to a different bus, use the 'i2c dev' command.
1346 Note that bus numbering is zero-based.
1350 This option specifies a list of I2C devices that will be skipped
1351 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1352 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1353 pairs. Otherwise, specify a 1D array of device addresses
1356 #undef CONFIG_I2C_MULTI_BUS
1357 #define CFG_I2C_NOPROBES {0x50,0x68}
1359 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1361 #define CONFIG_I2C_MULTI_BUS
1362 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1364 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1368 If defined, then this indicates the I2C bus number for DDR SPD.
1369 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1373 If defined, then this indicates the I2C bus number for the RTC.
1374 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1378 If defined, then this indicates the I2C bus number for the DTT.
1379 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1383 Define this option if you want to use Freescale's I2C driver in
1387 - SPI Support: CONFIG_SPI
1389 Enables SPI driver (so far only tested with
1390 SPI EEPROM, also an instance works with Crystal A/D and
1391 D/As on the SACSng board)
1395 Enables extended (16-bit) SPI EEPROM addressing.
1396 (symmetrical to CONFIG_I2C_X)
1400 Enables a software (bit-bang) SPI driver rather than
1401 using hardware support. This is a general purpose
1402 driver that only requires three general I/O port pins
1403 (two outputs, one input) to function. If this is
1404 defined, the board configuration must define several
1405 SPI configuration items (port pins to use, etc). For
1406 an example, see include/configs/sacsng.h.
1408 - FPGA Support: CONFIG_FPGA_COUNT
1410 Specify the number of FPGA devices to support.
1414 Used to specify the types of FPGA devices. For example,
1415 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1417 CFG_FPGA_PROG_FEEDBACK
1419 Enable printing of hash marks during FPGA configuration.
1423 Enable checks on FPGA configuration interface busy
1424 status by the configuration function. This option
1425 will require a board or device specific function to
1430 If defined, a function that provides delays in the FPGA
1431 configuration driver.
1433 CFG_FPGA_CHECK_CTRLC
1434 Allow Control-C to interrupt FPGA configuration
1436 CFG_FPGA_CHECK_ERROR
1438 Check for configuration errors during FPGA bitfile
1439 loading. For example, abort during Virtex II
1440 configuration if the INIT_B line goes low (which
1441 indicated a CRC error).
1445 Maximum time to wait for the INIT_B line to deassert
1446 after PROB_B has been deasserted during a Virtex II
1447 FPGA configuration sequence. The default time is 500
1452 Maximum time to wait for BUSY to deassert during
1453 Virtex II FPGA configuration. The default is 5 mS.
1455 CFG_FPGA_WAIT_CONFIG
1457 Time to wait after FPGA configuration. The default is
1460 - Configuration Management:
1463 If defined, this string will be added to the U-Boot
1464 version information (U_BOOT_VERSION)
1466 - Vendor Parameter Protection:
1468 U-Boot considers the values of the environment
1469 variables "serial#" (Board Serial Number) and
1470 "ethaddr" (Ethernet Address) to be parameters that
1471 are set once by the board vendor / manufacturer, and
1472 protects these variables from casual modification by
1473 the user. Once set, these variables are read-only,
1474 and write or delete attempts are rejected. You can
1475 change this behviour:
1477 If CONFIG_ENV_OVERWRITE is #defined in your config
1478 file, the write protection for vendor parameters is
1479 completely disabled. Anybody can change or delete
1482 Alternatively, if you #define _both_ CONFIG_ETHADDR
1483 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1484 ethernet address is installed in the environment,
1485 which can be changed exactly ONCE by the user. [The
1486 serial# is unaffected by this, i. e. it remains
1492 Define this variable to enable the reservation of
1493 "protected RAM", i. e. RAM which is not overwritten
1494 by U-Boot. Define CONFIG_PRAM to hold the number of
1495 kB you want to reserve for pRAM. You can overwrite
1496 this default value by defining an environment
1497 variable "pram" to the number of kB you want to
1498 reserve. Note that the board info structure will
1499 still show the full amount of RAM. If pRAM is
1500 reserved, a new environment variable "mem" will
1501 automatically be defined to hold the amount of
1502 remaining RAM in a form that can be passed as boot
1503 argument to Linux, for instance like that:
1505 setenv bootargs ... mem=\${mem}
1508 This way you can tell Linux not to use this memory,
1509 either, which results in a memory region that will
1510 not be affected by reboots.
1512 *WARNING* If your board configuration uses automatic
1513 detection of the RAM size, you must make sure that
1514 this memory test is non-destructive. So far, the
1515 following board configurations are known to be
1518 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1519 HERMES, IP860, RPXlite, LWMON, LANTEC,
1520 PCU_E, FLAGADM, TQM8260
1525 Define this variable to stop the system in case of a
1526 fatal error, so that you have to reset it manually.
1527 This is probably NOT a good idea for an embedded
1528 system where you want to system to reboot
1529 automatically as fast as possible, but it may be
1530 useful during development since you can try to debug
1531 the conditions that lead to the situation.
1533 CONFIG_NET_RETRY_COUNT
1535 This variable defines the number of retries for
1536 network operations like ARP, RARP, TFTP, or BOOTP
1537 before giving up the operation. If not defined, a
1538 default value of 5 is used.
1540 - Command Interpreter:
1541 CONFIG_AUTO_COMPLETE
1543 Enable auto completion of commands using TAB.
1545 Note that this feature has NOT been implemented yet
1546 for the "hush" shell.
1551 Define this variable to enable the "hush" shell (from
1552 Busybox) as command line interpreter, thus enabling
1553 powerful command line syntax like
1554 if...then...else...fi conditionals or `&&' and '||'
1555 constructs ("shell scripts").
1557 If undefined, you get the old, much simpler behaviour
1558 with a somewhat smaller memory footprint.
1563 This defines the secondary prompt string, which is
1564 printed when the command interpreter needs more input
1565 to complete a command. Usually "> ".
1569 In the current implementation, the local variables
1570 space and global environment variables space are
1571 separated. Local variables are those you define by
1572 simply typing `name=value'. To access a local
1573 variable later on, you have write `$name' or
1574 `${name}'; to execute the contents of a variable
1575 directly type `$name' at the command prompt.
1577 Global environment variables are those you use
1578 setenv/printenv to work with. To run a command stored
1579 in such a variable, you need to use the run command,
1580 and you must not use the '$' sign to access them.
1582 To store commands and special characters in a
1583 variable, please use double quotation marks
1584 surrounding the whole text of the variable, instead
1585 of the backslashes before semicolons and special
1588 - Commandline Editing and History:
1589 CONFIG_CMDLINE_EDITING
1591 Enable editiong and History functions for interactive
1592 commandline input operations
1594 - Default Environment:
1595 CONFIG_EXTRA_ENV_SETTINGS
1597 Define this to contain any number of null terminated
1598 strings (variable = value pairs) that will be part of
1599 the default environment compiled into the boot image.
1601 For example, place something like this in your
1602 board's config file:
1604 #define CONFIG_EXTRA_ENV_SETTINGS \
1608 Warning: This method is based on knowledge about the
1609 internal format how the environment is stored by the
1610 U-Boot code. This is NOT an official, exported
1611 interface! Although it is unlikely that this format
1612 will change soon, there is no guarantee either.
1613 You better know what you are doing here.
1615 Note: overly (ab)use of the default environment is
1616 discouraged. Make sure to check other ways to preset
1617 the environment like the autoscript function or the
1620 - DataFlash Support:
1621 CONFIG_HAS_DATAFLASH
1623 Defining this option enables DataFlash features and
1624 allows to read/write in Dataflash via the standard
1627 - SystemACE Support:
1630 Adding this option adds support for Xilinx SystemACE
1631 chips attached via some sort of local bus. The address
1632 of the chip must alsh be defined in the
1633 CFG_SYSTEMACE_BASE macro. For example:
1635 #define CONFIG_SYSTEMACE
1636 #define CFG_SYSTEMACE_BASE 0xf0000000
1638 When SystemACE support is added, the "ace" device type
1639 becomes available to the fat commands, i.e. fatls.
1641 - TFTP Fixed UDP Port:
1644 If this is defined, the environment variable tftpsrcp
1645 is used to supply the TFTP UDP source port value.
1646 If tftpsrcp isn't defined, the normal pseudo-random port
1647 number generator is used.
1649 Also, the environment variable tftpdstp is used to supply
1650 the TFTP UDP destination port value. If tftpdstp isn't
1651 defined, the normal port 69 is used.
1653 The purpose for tftpsrcp is to allow a TFTP server to
1654 blindly start the TFTP transfer using the pre-configured
1655 target IP address and UDP port. This has the effect of
1656 "punching through" the (Windows XP) firewall, allowing
1657 the remainder of the TFTP transfer to proceed normally.
1658 A better solution is to properly configure the firewall,
1659 but sometimes that is not allowed.
1661 - Show boot progress:
1662 CONFIG_SHOW_BOOT_PROGRESS
1664 Defining this option allows to add some board-
1665 specific code (calling a user-provided function
1666 "show_boot_progress(int)") that enables you to show
1667 the system's boot progress on some display (for
1668 example, some LED's) on your board. At the moment,
1669 the following checkpoints are implemented:
1672 1 common/cmd_bootm.c before attempting to boot an image
1673 -1 common/cmd_bootm.c Image header has bad magic number
1674 2 common/cmd_bootm.c Image header has correct magic number
1675 -2 common/cmd_bootm.c Image header has bad checksum
1676 3 common/cmd_bootm.c Image header has correct checksum
1677 -3 common/cmd_bootm.c Image data has bad checksum
1678 4 common/cmd_bootm.c Image data has correct checksum
1679 -4 common/cmd_bootm.c Image is for unsupported architecture
1680 5 common/cmd_bootm.c Architecture check OK
1681 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1682 6 common/cmd_bootm.c Image Type check OK
1683 -6 common/cmd_bootm.c gunzip uncompression error
1684 -7 common/cmd_bootm.c Unimplemented compression type
1685 7 common/cmd_bootm.c Uncompression OK
1686 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1687 8 common/cmd_bootm.c Image Type check OK
1688 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1689 9 common/cmd_bootm.c Start initial ramdisk verification
1690 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1691 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1692 10 common/cmd_bootm.c Ramdisk header is OK
1693 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1694 11 common/cmd_bootm.c Ramdisk data has correct checksum
1695 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1696 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1697 13 common/cmd_bootm.c Start multifile image verification
1698 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1699 15 common/cmd_bootm.c All preparation done, transferring control to OS
1701 -30 lib_ppc/board.c Fatal error, hang the system
1702 -31 post/post.c POST test failed, detected by post_output_backlog()
1703 -32 post/post.c POST test failed, detected by post_run_single()
1705 34 common/cmd_doc.c before loading a Image from a DOC device
1706 -35 common/cmd_doc.c Bad usage of "doc" command
1707 35 common/cmd_doc.c correct usage of "doc" command
1708 -36 common/cmd_doc.c No boot device
1709 36 common/cmd_doc.c correct boot device
1710 -37 common/cmd_doc.c Unknown Chip ID on boot device
1711 37 common/cmd_doc.c correct chip ID found, device available
1712 -38 common/cmd_doc.c Read Error on boot device
1713 38 common/cmd_doc.c reading Image header from DOC device OK
1714 -39 common/cmd_doc.c Image header has bad magic number
1715 39 common/cmd_doc.c Image header has correct magic number
1716 -40 common/cmd_doc.c Error reading Image from DOC device
1717 40 common/cmd_doc.c Image header has correct magic number
1718 41 common/cmd_ide.c before loading a Image from a IDE device
1719 -42 common/cmd_ide.c Bad usage of "ide" command
1720 42 common/cmd_ide.c correct usage of "ide" command
1721 -43 common/cmd_ide.c No boot device
1722 43 common/cmd_ide.c boot device found
1723 -44 common/cmd_ide.c Device not available
1724 44 common/cmd_ide.c Device available
1725 -45 common/cmd_ide.c wrong partition selected
1726 45 common/cmd_ide.c partition selected
1727 -46 common/cmd_ide.c Unknown partition table
1728 46 common/cmd_ide.c valid partition table found
1729 -47 common/cmd_ide.c Invalid partition type
1730 47 common/cmd_ide.c correct partition type
1731 -48 common/cmd_ide.c Error reading Image Header on boot device
1732 48 common/cmd_ide.c reading Image Header from IDE device OK
1733 -49 common/cmd_ide.c Image header has bad magic number
1734 49 common/cmd_ide.c Image header has correct magic number
1735 -50 common/cmd_ide.c Image header has bad checksum
1736 50 common/cmd_ide.c Image header has correct checksum
1737 -51 common/cmd_ide.c Error reading Image from IDE device
1738 51 common/cmd_ide.c reading Image from IDE device OK
1739 52 common/cmd_nand.c before loading a Image from a NAND device
1740 -53 common/cmd_nand.c Bad usage of "nand" command
1741 53 common/cmd_nand.c correct usage of "nand" command
1742 -54 common/cmd_nand.c No boot device
1743 54 common/cmd_nand.c boot device found
1744 -55 common/cmd_nand.c Unknown Chip ID on boot device
1745 55 common/cmd_nand.c correct chip ID found, device available
1746 -56 common/cmd_nand.c Error reading Image Header on boot device
1747 56 common/cmd_nand.c reading Image Header from NAND device OK
1748 -57 common/cmd_nand.c Image header has bad magic number
1749 57 common/cmd_nand.c Image header has correct magic number
1750 -58 common/cmd_nand.c Error reading Image from NAND device
1751 58 common/cmd_nand.c reading Image from NAND device OK
1753 -60 common/env_common.c Environment has a bad CRC, using default
1755 64 net/eth.c starting with Ethernetconfiguration.
1756 -64 net/eth.c no Ethernet found.
1757 65 net/eth.c Ethernet found.
1759 -80 common/cmd_net.c usage wrong
1760 80 common/cmd_net.c before calling NetLoop()
1761 -81 common/cmd_net.c some error in NetLoop() occured
1762 81 common/cmd_net.c NetLoop() back without error
1763 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1764 82 common/cmd_net.c trying automatic boot
1765 83 common/cmd_net.c running autoscript
1766 -83 common/cmd_net.c some error in automatic boot or autoscript
1767 84 common/cmd_net.c end without errors
1772 [so far only for SMDK2400 and TRAB boards]
1774 - Modem support endable:
1775 CONFIG_MODEM_SUPPORT
1777 - RTS/CTS Flow control enable:
1780 - Modem debug support:
1781 CONFIG_MODEM_SUPPORT_DEBUG
1783 Enables debugging stuff (char screen[1024], dbg())
1784 for modem support. Useful only with BDI2000.
1786 - Interrupt support (PPC):
1788 There are common interrupt_init() and timer_interrupt()
1789 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1790 for cpu specific initialization. interrupt_init_cpu()
1791 should set decrementer_count to appropriate value. If
1792 cpu resets decrementer automatically after interrupt
1793 (ppc4xx) it should set decrementer_count to zero.
1794 timer_interrupt() calls timer_interrupt_cpu() for cpu
1795 specific handling. If board has watchdog / status_led
1796 / other_activity_monitor it works automatically from
1797 general timer_interrupt().
1801 In the target system modem support is enabled when a
1802 specific key (key combination) is pressed during
1803 power-on. Otherwise U-Boot will boot normally
1804 (autoboot). The key_pressed() fuction is called from
1805 board_init(). Currently key_pressed() is a dummy
1806 function, returning 1 and thus enabling modem
1809 If there are no modem init strings in the
1810 environment, U-Boot proceed to autoboot; the
1811 previous output (banner, info printfs) will be
1814 See also: doc/README.Modem
1817 Configuration Settings:
1818 -----------------------
1820 - CFG_LONGHELP: Defined when you want long help messages included;
1821 undefine this when you're short of memory.
1823 - CFG_PROMPT: This is what U-Boot prints on the console to
1824 prompt for user input.
1826 - CFG_CBSIZE: Buffer size for input from the Console
1828 - CFG_PBSIZE: Buffer size for Console output
1830 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1832 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1833 the application (usually a Linux kernel) when it is
1836 - CFG_BAUDRATE_TABLE:
1837 List of legal baudrate settings for this board.
1839 - CFG_CONSOLE_INFO_QUIET
1840 Suppress display of console information at boot.
1842 - CFG_CONSOLE_IS_IN_ENV
1843 If the board specific function
1844 extern int overwrite_console (void);
1845 returns 1, the stdin, stderr and stdout are switched to the
1846 serial port, else the settings in the environment are used.
1848 - CFG_CONSOLE_OVERWRITE_ROUTINE
1849 Enable the call to overwrite_console().
1851 - CFG_CONSOLE_ENV_OVERWRITE
1852 Enable overwrite of previous console environment settings.
1854 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1855 Begin and End addresses of the area used by the
1859 Enable an alternate, more extensive memory test.
1861 - CFG_MEMTEST_SCRATCH:
1862 Scratch address used by the alternate memory test
1863 You only need to set this if address zero isn't writeable
1865 - CFG_TFTP_LOADADDR:
1866 Default load address for network file downloads
1868 - CFG_LOADS_BAUD_CHANGE:
1869 Enable temporary baudrate change while serial download
1872 Physical start address of SDRAM. _Must_ be 0 here.
1875 Physical start address of Motherboard I/O (if using a
1879 Physical start address of Flash memory.
1882 Physical start address of boot monitor code (set by
1883 make config files to be same as the text base address
1884 (TEXT_BASE) used when linking) - same as
1885 CFG_FLASH_BASE when booting from flash.
1888 Size of memory reserved for monitor code, used to
1889 determine _at_compile_time_ (!) if the environment is
1890 embedded within the U-Boot image, or in a separate
1894 Size of DRAM reserved for malloc() use.
1897 Normally compressed uImages are limited to an
1898 uncompressed size of 8 MBytes. If this is not enough,
1899 you can define CFG_BOOTM_LEN in your board config file
1900 to adjust this setting to your needs.
1903 Maximum size of memory mapped by the startup code of
1904 the Linux kernel; all data that must be processed by
1905 the Linux kernel (bd_info, boot arguments, eventually
1906 initrd image) must be put below this limit.
1908 - CFG_MAX_FLASH_BANKS:
1909 Max number of Flash memory banks
1911 - CFG_MAX_FLASH_SECT:
1912 Max number of sectors on a Flash chip
1914 - CFG_FLASH_ERASE_TOUT:
1915 Timeout for Flash erase operations (in ms)
1917 - CFG_FLASH_WRITE_TOUT:
1918 Timeout for Flash write operations (in ms)
1920 - CFG_FLASH_LOCK_TOUT
1921 Timeout for Flash set sector lock bit operation (in ms)
1923 - CFG_FLASH_UNLOCK_TOUT
1924 Timeout for Flash clear lock bits operation (in ms)
1926 - CFG_FLASH_PROTECTION
1927 If defined, hardware flash sectors protection is used
1928 instead of U-Boot software protection.
1930 - CFG_DIRECT_FLASH_TFTP:
1932 Enable TFTP transfers directly to flash memory;
1933 without this option such a download has to be
1934 performed in two steps: (1) download to RAM, and (2)
1935 copy from RAM to flash.
1937 The two-step approach is usually more reliable, since
1938 you can check if the download worked before you erase
1939 the flash, but in some situations (when sytem RAM is
1940 too limited to allow for a tempory copy of the
1941 downloaded image) this option may be very useful.
1944 Define if the flash driver uses extra elements in the
1945 common flash structure for storing flash geometry.
1947 - CFG_FLASH_CFI_DRIVER
1948 This option also enables the building of the cfi_flash driver
1949 in the drivers directory
1951 - CFG_FLASH_QUIET_TEST
1952 If this option is defined, the common CFI flash doesn't
1953 print it's warning upon not recognized FLASH banks. This
1954 is useful, if some of the configured banks are only
1955 optionally available.
1957 - CFG_RX_ETH_BUFFER:
1958 Defines the number of ethernet receive buffers. On some
1959 ethernet controllers it is recommended to set this value
1960 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1961 buffers can be full shortly after enabling the interface
1962 on high ethernet traffic.
1963 Defaults to 4 if not defined.
1965 The following definitions that deal with the placement and management
1966 of environment data (variable area); in general, we support the
1967 following configurations:
1969 - CFG_ENV_IS_IN_FLASH:
1971 Define this if the environment is in flash memory.
1973 a) The environment occupies one whole flash sector, which is
1974 "embedded" in the text segment with the U-Boot code. This
1975 happens usually with "bottom boot sector" or "top boot
1976 sector" type flash chips, which have several smaller
1977 sectors at the start or the end. For instance, such a
1978 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1979 such a case you would place the environment in one of the
1980 4 kB sectors - with U-Boot code before and after it. With
1981 "top boot sector" type flash chips, you would put the
1982 environment in one of the last sectors, leaving a gap
1983 between U-Boot and the environment.
1987 Offset of environment data (variable area) to the
1988 beginning of flash memory; for instance, with bottom boot
1989 type flash chips the second sector can be used: the offset
1990 for this sector is given here.
1992 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1996 This is just another way to specify the start address of
1997 the flash sector containing the environment (instead of
2000 - CFG_ENV_SECT_SIZE:
2002 Size of the sector containing the environment.
2005 b) Sometimes flash chips have few, equal sized, BIG sectors.
2006 In such a case you don't want to spend a whole sector for
2011 If you use this in combination with CFG_ENV_IS_IN_FLASH
2012 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2013 of this flash sector for the environment. This saves
2014 memory for the RAM copy of the environment.
2016 It may also save flash memory if you decide to use this
2017 when your environment is "embedded" within U-Boot code,
2018 since then the remainder of the flash sector could be used
2019 for U-Boot code. It should be pointed out that this is
2020 STRONGLY DISCOURAGED from a robustness point of view:
2021 updating the environment in flash makes it always
2022 necessary to erase the WHOLE sector. If something goes
2023 wrong before the contents has been restored from a copy in
2024 RAM, your target system will be dead.
2026 - CFG_ENV_ADDR_REDUND
2029 These settings describe a second storage area used to hold
2030 a redundand copy of the environment data, so that there is
2031 a valid backup copy in case there is a power failure during
2032 a "saveenv" operation.
2034 BE CAREFUL! Any changes to the flash layout, and some changes to the
2035 source code will make it necessary to adapt <board>/u-boot.lds*
2039 - CFG_ENV_IS_IN_NVRAM:
2041 Define this if you have some non-volatile memory device
2042 (NVRAM, battery buffered SRAM) which you want to use for the
2048 These two #defines are used to determin the memory area you
2049 want to use for environment. It is assumed that this memory
2050 can just be read and written to, without any special
2053 BE CAREFUL! The first access to the environment happens quite early
2054 in U-Boot initalization (when we try to get the setting of for the
2055 console baudrate). You *MUST* have mappend your NVRAM area then, or
2058 Please note that even with NVRAM we still use a copy of the
2059 environment in RAM: we could work on NVRAM directly, but we want to
2060 keep settings there always unmodified except somebody uses "saveenv"
2061 to save the current settings.
2064 - CFG_ENV_IS_IN_EEPROM:
2066 Use this if you have an EEPROM or similar serial access
2067 device and a driver for it.
2072 These two #defines specify the offset and size of the
2073 environment area within the total memory of your EEPROM.
2075 - CFG_I2C_EEPROM_ADDR:
2076 If defined, specified the chip address of the EEPROM device.
2077 The default address is zero.
2079 - CFG_EEPROM_PAGE_WRITE_BITS:
2080 If defined, the number of bits used to address bytes in a
2081 single page in the EEPROM device. A 64 byte page, for example
2082 would require six bits.
2084 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2085 If defined, the number of milliseconds to delay between
2086 page writes. The default is zero milliseconds.
2088 - CFG_I2C_EEPROM_ADDR_LEN:
2089 The length in bytes of the EEPROM memory array address. Note
2090 that this is NOT the chip address length!
2092 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2093 EEPROM chips that implement "address overflow" are ones
2094 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2095 address and the extra bits end up in the "chip address" bit
2096 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2099 Note that we consider the length of the address field to
2100 still be one byte because the extra address bits are hidden
2101 in the chip address.
2104 The size in bytes of the EEPROM device.
2107 - CFG_ENV_IS_IN_DATAFLASH:
2109 Define this if you have a DataFlash memory device which you
2110 want to use for the environment.
2116 These three #defines specify the offset and size of the
2117 environment area within the total memory of your DataFlash placed
2118 at the specified address.
2120 - CFG_ENV_IS_IN_NAND:
2122 Define this if you have a NAND device which you want to use
2123 for the environment.
2128 These two #defines specify the offset and size of the environment
2129 area within the first NAND device.
2131 - CFG_ENV_OFFSET_REDUND
2133 This setting describes a second storage area of CFG_ENV_SIZE
2134 size used to hold a redundant copy of the environment data,
2135 so that there is a valid backup copy in case there is a
2136 power failure during a "saveenv" operation.
2138 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2139 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2140 the NAND devices block size.
2142 - CFG_SPI_INIT_OFFSET
2144 Defines offset to the initial SPI buffer area in DPRAM. The
2145 area is used at an early stage (ROM part) if the environment
2146 is configured to reside in the SPI EEPROM: We need a 520 byte
2147 scratch DPRAM area. It is used between the two initialization
2148 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2149 to be a good choice since it makes it far enough from the
2150 start of the data area as well as from the stack pointer.
2152 Please note that the environment is read-only as long as the monitor
2153 has been relocated to RAM and a RAM copy of the environment has been
2154 created; also, when using EEPROM you will have to use getenv_r()
2155 until then to read environment variables.
2157 The environment is protected by a CRC32 checksum. Before the monitor
2158 is relocated into RAM, as a result of a bad CRC you will be working
2159 with the compiled-in default environment - *silently*!!! [This is
2160 necessary, because the first environment variable we need is the
2161 "baudrate" setting for the console - if we have a bad CRC, we don't
2162 have any device yet where we could complain.]
2164 Note: once the monitor has been relocated, then it will complain if
2165 the default environment is used; a new CRC is computed as soon as you
2166 use the "saveenv" command to store a valid environment.
2168 - CFG_FAULT_ECHO_LINK_DOWN:
2169 Echo the inverted Ethernet link state to the fault LED.
2171 Note: If this option is active, then CFG_FAULT_MII_ADDR
2172 also needs to be defined.
2174 - CFG_FAULT_MII_ADDR:
2175 MII address of the PHY to check for the Ethernet link state.
2177 - CFG_64BIT_VSPRINTF:
2178 Makes vsprintf (and all *printf functions) support printing
2179 of 64bit values by using the L quantifier
2181 - CFG_64BIT_STRTOUL:
2182 Adds simple_strtoull that returns a 64bit value
2184 Low Level (hardware related) configuration options:
2185 ---------------------------------------------------
2187 - CFG_CACHELINE_SIZE:
2188 Cache Line Size of the CPU.
2191 Default address of the IMMR after system reset.
2193 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2194 and RPXsuper) to be able to adjust the position of
2195 the IMMR register after a reset.
2197 - Floppy Disk Support:
2198 CFG_FDC_DRIVE_NUMBER
2200 the default drive number (default value 0)
2204 defines the spacing between fdc chipset registers
2209 defines the offset of register from address. It
2210 depends on which part of the data bus is connected to
2211 the fdc chipset. (default value 0)
2213 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2214 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2217 if CFG_FDC_HW_INIT is defined, then the function
2218 fdc_hw_init() is called at the beginning of the FDC
2219 setup. fdc_hw_init() must be provided by the board
2220 source code. It is used to make hardware dependant
2223 - CFG_IMMR: Physical address of the Internal Memory.
2224 DO NOT CHANGE unless you know exactly what you're
2225 doing! (11-4) [MPC8xx/82xx systems only]
2227 - CFG_INIT_RAM_ADDR:
2229 Start address of memory area that can be used for
2230 initial data and stack; please note that this must be
2231 writable memory that is working WITHOUT special
2232 initialization, i. e. you CANNOT use normal RAM which
2233 will become available only after programming the
2234 memory controller and running certain initialization
2237 U-Boot uses the following memory types:
2238 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2239 - MPC824X: data cache
2240 - PPC4xx: data cache
2242 - CFG_GBL_DATA_OFFSET:
2244 Offset of the initial data structure in the memory
2245 area defined by CFG_INIT_RAM_ADDR. Usually
2246 CFG_GBL_DATA_OFFSET is chosen such that the initial
2247 data is located at the end of the available space
2248 (sometimes written as (CFG_INIT_RAM_END -
2249 CFG_INIT_DATA_SIZE), and the initial stack is just
2250 below that area (growing from (CFG_INIT_RAM_ADDR +
2251 CFG_GBL_DATA_OFFSET) downward.
2254 On the MPC824X (or other systems that use the data
2255 cache for initial memory) the address chosen for
2256 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2257 point to an otherwise UNUSED address space between
2258 the top of RAM and the start of the PCI space.
2260 - CFG_SIUMCR: SIU Module Configuration (11-6)
2262 - CFG_SYPCR: System Protection Control (11-9)
2264 - CFG_TBSCR: Time Base Status and Control (11-26)
2266 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2268 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2270 - CFG_SCCR: System Clock and reset Control Register (15-27)
2272 - CFG_OR_TIMING_SDRAM:
2276 periodic timer for refresh
2278 - CFG_DER: Debug Event Register (37-47)
2280 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2281 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2282 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2284 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2286 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2287 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2288 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2289 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2291 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2292 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2293 Machine Mode Register and Memory Periodic Timer
2294 Prescaler definitions (SDRAM timing)
2296 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2297 enable I2C microcode relocation patch (MPC8xx);
2298 define relocation offset in DPRAM [DSP2]
2300 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2301 enable SPI microcode relocation patch (MPC8xx);
2302 define relocation offset in DPRAM [SCC4]
2305 Use OSCM clock mode on MBX8xx board. Be careful,
2306 wrong setting might damage your board. Read
2307 doc/README.MBX before setting this variable!
2309 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2310 Offset of the bootmode word in DPRAM used by post
2311 (Power On Self Tests). This definition overrides
2312 #define'd default value in commproc.h resp.
2315 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2316 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2317 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2318 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2319 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2320 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2321 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2322 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2323 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2326 Get DDR timing information from an I2C EEPROM. Common with pluggable
2327 memory modules such as SODIMMs
2329 I2C address of the SPD EEPROM
2332 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2333 Note that the value must resolve to something your driver can deal with.
2335 - CFG_83XX_DDR_USES_CS0
2336 Only for 83xx systems. If specified, then DDR should be configured
2337 using CS0 and CS1 instead of CS2 and CS3.
2339 - CFG_83XX_DDR_USES_CS0
2340 Only for 83xx systems. If specified, then DDR should be configured
2341 using CS0 and CS1 instead of CS2 and CS3.
2343 - CONFIG_ETHER_ON_FEC[12]
2344 Define to enable FEC[12] on a 8xx series processor.
2346 - CONFIG_FEC[12]_PHY
2347 Define to the hardcoded PHY address which corresponds
2348 to the given FEC; i. e.
2349 #define CONFIG_FEC1_PHY 4
2350 means that the PHY with address 4 is connected to FEC1
2352 When set to -1, means to probe for first available.
2354 - CONFIG_FEC[12]_PHY_NORXERR
2355 The PHY does not have a RXERR line (RMII only).
2356 (so program the FEC to ignore it).
2359 Enable RMII mode for all FECs.
2360 Note that this is a global option, we can't
2361 have one FEC in standard MII mode and another in RMII mode.
2363 - CONFIG_CRC32_VERIFY
2364 Add a verify option to the crc32 command.
2367 => crc32 -v <address> <count> <crc32>
2369 Where address/count indicate a memory area
2370 and crc32 is the correct crc32 which the
2374 Add the "loopw" memory command. This only takes effect if
2375 the memory commands are activated globally (CONFIG_CMD_MEM).
2378 Add the "mdc" and "mwc" memory commands. These are cyclic
2383 This command will print 4 bytes (10,11,12,13) each 500 ms.
2385 => mwc.l 100 12345678 10
2386 This command will write 12345678 to address 100 all 10 ms.
2388 This only takes effect if the memory commands are activated
2389 globally (CONFIG_CMD_MEM).
2391 - CONFIG_SKIP_LOWLEVEL_INIT
2392 - CONFIG_SKIP_RELOCATE_UBOOT
2394 [ARM only] If these variables are defined, then
2395 certain low level initializations (like setting up
2396 the memory controller) are omitted and/or U-Boot does
2397 not relocate itself into RAM.
2398 Normally these variables MUST NOT be defined. The
2399 only exception is when U-Boot is loaded (to RAM) by
2400 some other boot loader or by a debugger which
2401 performs these intializations itself.
2404 Building the Software:
2405 ======================
2407 Building U-Boot has been tested in native PPC environments (on a
2408 PowerBook G3 running LinuxPPC 2000) and in cross environments
2409 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2412 If you are not using a native PPC environment, it is assumed that you
2413 have the GNU cross compiling tools available in your path and named
2414 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2415 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2416 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2419 CROSS_COMPILE = ppc_4xx-
2422 U-Boot is intended to be simple to build. After installing the
2423 sources you must configure U-Boot for one specific board type. This
2428 where "NAME_config" is the name of one of the existing
2429 configurations; the following names are supported:
2431 ADCIOP_config FPS860L_config omap730p2_config
2432 ADS860_config GEN860T_config pcu_e_config
2434 AR405_config GENIETV_config PIP405_config
2435 at91rm9200dk_config GTH_config QS823_config
2436 CANBT_config hermes_config QS850_config
2437 cmi_mpc5xx_config hymod_config QS860T_config
2438 cogent_common_config IP860_config RPXlite_config
2439 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2440 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2441 CPCI405_config JSE_config rsdproto_config
2442 CPCIISER4_config LANTEC_config Sandpoint8240_config
2443 csb272_config lwmon_config sbc8260_config
2444 CU824_config MBX860T_config sbc8560_33_config
2445 DUET_ADS_config MBX_config sbc8560_66_config
2446 EBONY_config mpc7448hpc2_config SM850_config
2447 ELPT860_config MPC8260ADS_config SPD823TS_config
2448 ESTEEM192E_config MPC8540ADS_config stxgp3_config
2449 ETX094_config MPC8540EVAL_config SXNI855T_config
2450 FADS823_config NMPC8560ADS_config TQM823L_config
2451 FADS850SAR_config NETVIA_config TQM850L_config
2452 FADS860T_config omap1510inn_config TQM855L_config
2453 FPS850L_config omap1610h2_config TQM860L_config
2454 omap1610inn_config walnut_config
2455 omap5912osk_config Yukon8220_config
2456 omap2420h4_config ZPC1900_config
2458 Note: for some board special configuration names may exist; check if
2459 additional information is available from the board vendor; for
2460 instance, the TQM823L systems are available without (standard)
2461 or with LCD support. You can select such additional "features"
2462 when chosing the configuration, i. e.
2465 - will configure for a plain TQM823L, i. e. no LCD support
2467 make TQM823L_LCD_config
2468 - will configure for a TQM823L with U-Boot console on LCD
2473 Finally, type "make all", and you should get some working U-Boot
2474 images ready for download to / installation on your system:
2476 - "u-boot.bin" is a raw binary image
2477 - "u-boot" is an image in ELF binary format
2478 - "u-boot.srec" is in Motorola S-Record format
2480 By default the build is performed locally and the objects are saved
2481 in the source directory. One of the two methods can be used to change
2482 this behavior and build U-Boot to some external directory:
2484 1. Add O= to the make command line invocations:
2486 make O=/tmp/build distclean
2487 make O=/tmp/build NAME_config
2488 make O=/tmp/build all
2490 2. Set environment variable BUILD_DIR to point to the desired location:
2492 export BUILD_DIR=/tmp/build
2497 Note that the command line "O=" setting overrides the BUILD_DIR environment
2501 Please be aware that the Makefiles assume you are using GNU make, so
2502 for instance on NetBSD you might need to use "gmake" instead of
2506 If the system board that you have is not listed, then you will need
2507 to port U-Boot to your hardware platform. To do this, follow these
2510 1. Add a new configuration option for your board to the toplevel
2511 "Makefile" and to the "MAKEALL" script, using the existing
2512 entries as examples. Note that here and at many other places
2513 boards and other names are listed in alphabetical sort order. Please
2515 2. Create a new directory to hold your board specific code. Add any
2516 files you need. In your board directory, you will need at least
2517 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2518 3. Create a new configuration file "include/configs/<board>.h" for
2520 3. If you're porting U-Boot to a new CPU, then also create a new
2521 directory to hold your CPU specific code. Add any files you need.
2522 4. Run "make <board>_config" with your new name.
2523 5. Type "make", and you should get a working "u-boot.srec" file
2524 to be installed on your target system.
2525 6. Debug and solve any problems that might arise.
2526 [Of course, this last step is much harder than it sounds.]
2529 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2530 ==============================================================
2532 If you have modified U-Boot sources (for instance added a new board
2533 or support for new devices, a new CPU, etc.) you are expected to
2534 provide feedback to the other developers. The feedback normally takes
2535 the form of a "patch", i. e. a context diff against a certain (latest
2536 official or latest in CVS) version of U-Boot sources.
2538 But before you submit such a patch, please verify that your modifi-
2539 cation did not break existing code. At least make sure that *ALL* of
2540 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2541 just run the "MAKEALL" script, which will configure and build U-Boot
2542 for ALL supported system. Be warned, this will take a while. You can
2543 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2544 environment variable to the script, i. e. to use the cross tools from
2545 MontaVista's Hard Hat Linux you can type
2547 CROSS_COMPILE=ppc_8xx- MAKEALL
2549 or to build on a native PowerPC system you can type
2551 CROSS_COMPILE=' ' MAKEALL
2553 When using the MAKEALL script, the default behaviour is to build U-Boot
2554 in the source directory. This location can be changed by setting the
2555 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2556 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2557 <source dir>/LOG directory. This default location can be changed by
2558 setting the MAKEALL_LOGDIR environment variable. For example:
2560 export BUILD_DIR=/tmp/build
2561 export MAKEALL_LOGDIR=/tmp/log
2562 CROSS_COMPILE=ppc_8xx- MAKEALL
2564 With the above settings build objects are saved in the /tmp/build, log
2565 files are saved in the /tmp/log and the source tree remains clean during
2566 the whole build process.
2569 See also "U-Boot Porting Guide" below.
2572 Monitor Commands - Overview:
2573 ============================
2575 go - start application at address 'addr'
2576 run - run commands in an environment variable
2577 bootm - boot application image from memory
2578 bootp - boot image via network using BootP/TFTP protocol
2579 tftpboot- boot image via network using TFTP protocol
2580 and env variables "ipaddr" and "serverip"
2581 (and eventually "gatewayip")
2582 rarpboot- boot image via network using RARP/TFTP protocol
2583 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2584 loads - load S-Record file over serial line
2585 loadb - load binary file over serial line (kermit mode)
2587 mm - memory modify (auto-incrementing)
2588 nm - memory modify (constant address)
2589 mw - memory write (fill)
2591 cmp - memory compare
2592 crc32 - checksum calculation
2593 imd - i2c memory display
2594 imm - i2c memory modify (auto-incrementing)
2595 inm - i2c memory modify (constant address)
2596 imw - i2c memory write (fill)
2597 icrc32 - i2c checksum calculation
2598 iprobe - probe to discover valid I2C chip addresses
2599 iloop - infinite loop on address range
2600 isdram - print SDRAM configuration information
2601 sspi - SPI utility commands
2602 base - print or set address offset
2603 printenv- print environment variables
2604 setenv - set environment variables
2605 saveenv - save environment variables to persistent storage
2606 protect - enable or disable FLASH write protection
2607 erase - erase FLASH memory
2608 flinfo - print FLASH memory information
2609 bdinfo - print Board Info structure
2610 iminfo - print header information for application image
2611 coninfo - print console devices and informations
2612 ide - IDE sub-system
2613 loop - infinite loop on address range
2614 loopw - infinite write loop on address range
2615 mtest - simple RAM test
2616 icache - enable or disable instruction cache
2617 dcache - enable or disable data cache
2618 reset - Perform RESET of the CPU
2619 echo - echo args to console
2620 version - print monitor version
2621 help - print online help
2622 ? - alias for 'help'
2625 Monitor Commands - Detailed Description:
2626 ========================================
2630 For now: just type "help <command>".
2633 Environment Variables:
2634 ======================
2636 U-Boot supports user configuration using Environment Variables which
2637 can be made persistent by saving to Flash memory.
2639 Environment Variables are set using "setenv", printed using
2640 "printenv", and saved to Flash using "saveenv". Using "setenv"
2641 without a value can be used to delete a variable from the
2642 environment. As long as you don't save the environment you are
2643 working with an in-memory copy. In case the Flash area containing the
2644 environment is erased by accident, a default environment is provided.
2646 Some configuration options can be set using Environment Variables:
2648 baudrate - see CONFIG_BAUDRATE
2650 bootdelay - see CONFIG_BOOTDELAY
2652 bootcmd - see CONFIG_BOOTCOMMAND
2654 bootargs - Boot arguments when booting an RTOS image
2656 bootfile - Name of the image to load with TFTP
2658 autoload - if set to "no" (any string beginning with 'n'),
2659 "bootp" will just load perform a lookup of the
2660 configuration from the BOOTP server, but not try to
2661 load any image using TFTP
2663 autostart - if set to "yes", an image loaded using the "bootp",
2664 "rarpboot", "tftpboot" or "diskboot" commands will
2665 be automatically started (by internally calling
2668 If set to "no", a standalone image passed to the
2669 "bootm" command will be copied to the load address
2670 (and eventually uncompressed), but NOT be started.
2671 This can be used to load and uncompress arbitrary
2674 i2cfast - (PPC405GP|PPC405EP only)
2675 if set to 'y' configures Linux I2C driver for fast
2676 mode (400kHZ). This environment variable is used in
2677 initialization code. So, for changes to be effective
2678 it must be saved and board must be reset.
2680 initrd_high - restrict positioning of initrd images:
2681 If this variable is not set, initrd images will be
2682 copied to the highest possible address in RAM; this
2683 is usually what you want since it allows for
2684 maximum initrd size. If for some reason you want to
2685 make sure that the initrd image is loaded below the
2686 CFG_BOOTMAPSZ limit, you can set this environment
2687 variable to a value of "no" or "off" or "0".
2688 Alternatively, you can set it to a maximum upper
2689 address to use (U-Boot will still check that it
2690 does not overwrite the U-Boot stack and data).
2692 For instance, when you have a system with 16 MB
2693 RAM, and want to reserve 4 MB from use by Linux,
2694 you can do this by adding "mem=12M" to the value of
2695 the "bootargs" variable. However, now you must make
2696 sure that the initrd image is placed in the first
2697 12 MB as well - this can be done with
2699 setenv initrd_high 00c00000
2701 If you set initrd_high to 0xFFFFFFFF, this is an
2702 indication to U-Boot that all addresses are legal
2703 for the Linux kernel, including addresses in flash
2704 memory. In this case U-Boot will NOT COPY the
2705 ramdisk at all. This may be useful to reduce the
2706 boot time on your system, but requires that this
2707 feature is supported by your Linux kernel.
2709 ipaddr - IP address; needed for tftpboot command
2711 loadaddr - Default load address for commands like "bootp",
2712 "rarpboot", "tftpboot", "loadb" or "diskboot"
2714 loads_echo - see CONFIG_LOADS_ECHO
2716 serverip - TFTP server IP address; needed for tftpboot command
2718 bootretry - see CONFIG_BOOT_RETRY_TIME
2720 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2722 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2724 ethprime - When CONFIG_NET_MULTI is enabled controls which
2725 interface is used first.
2727 ethact - When CONFIG_NET_MULTI is enabled controls which
2728 interface is currently active. For example you
2729 can do the following
2731 => setenv ethact FEC ETHERNET
2732 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2733 => setenv ethact SCC ETHERNET
2734 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2736 netretry - When set to "no" each network operation will
2737 either succeed or fail without retrying.
2738 When set to "once" the network operation will
2739 fail when all the available network interfaces
2740 are tried once without success.
2741 Useful on scripts which control the retry operation
2744 tftpsrcport - If this is set, the value is used for TFTP's
2747 tftpdstport - If this is set, the value is used for TFTP's UDP
2748 destination port instead of the Well Know Port 69.
2750 vlan - When set to a value < 4095 the traffic over
2751 ethernet is encapsulated/received over 802.1q
2754 The following environment variables may be used and automatically
2755 updated by the network boot commands ("bootp" and "rarpboot"),
2756 depending the information provided by your boot server:
2758 bootfile - see above
2759 dnsip - IP address of your Domain Name Server
2760 dnsip2 - IP address of your secondary Domain Name Server
2761 gatewayip - IP address of the Gateway (Router) to use
2762 hostname - Target hostname
2764 netmask - Subnet Mask
2765 rootpath - Pathname of the root filesystem on the NFS server
2766 serverip - see above
2769 There are two special Environment Variables:
2771 serial# - contains hardware identification information such
2772 as type string and/or serial number
2773 ethaddr - Ethernet address
2775 These variables can be set only once (usually during manufacturing of
2776 the board). U-Boot refuses to delete or overwrite these variables
2777 once they have been set once.
2780 Further special Environment Variables:
2782 ver - Contains the U-Boot version string as printed
2783 with the "version" command. This variable is
2784 readonly (see CONFIG_VERSION_VARIABLE).
2787 Please note that changes to some configuration parameters may take
2788 only effect after the next boot (yes, that's just like Windoze :-).
2791 Command Line Parsing:
2792 =====================
2794 There are two different command line parsers available with U-Boot:
2795 the old "simple" one, and the much more powerful "hush" shell:
2797 Old, simple command line parser:
2798 --------------------------------
2800 - supports environment variables (through setenv / saveenv commands)
2801 - several commands on one line, separated by ';'
2802 - variable substitution using "... ${name} ..." syntax
2803 - special characters ('$', ';') can be escaped by prefixing with '\',
2805 setenv bootcmd bootm \${address}
2806 - You can also escape text by enclosing in single apostrophes, for example:
2807 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2812 - similar to Bourne shell, with control structures like
2813 if...then...else...fi, for...do...done; while...do...done,
2814 until...do...done, ...
2815 - supports environment ("global") variables (through setenv / saveenv
2816 commands) and local shell variables (through standard shell syntax
2817 "name=value"); only environment variables can be used with "run"
2823 (1) If a command line (or an environment variable executed by a "run"
2824 command) contains several commands separated by semicolon, and
2825 one of these commands fails, then the remaining commands will be
2828 (2) If you execute several variables with one call to run (i. e.
2829 calling run with a list af variables as arguments), any failing
2830 command will cause "run" to terminate, i. e. the remaining
2831 variables are not executed.
2833 Note for Redundant Ethernet Interfaces:
2834 =======================================
2836 Some boards come with redundant ethernet interfaces; U-Boot supports
2837 such configurations and is capable of automatic selection of a
2838 "working" interface when needed. MAC assignment works as follows:
2840 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2841 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2842 "eth1addr" (=>eth1), "eth2addr", ...
2844 If the network interface stores some valid MAC address (for instance
2845 in SROM), this is used as default address if there is NO correspon-
2846 ding setting in the environment; if the corresponding environment
2847 variable is set, this overrides the settings in the card; that means:
2849 o If the SROM has a valid MAC address, and there is no address in the
2850 environment, the SROM's address is used.
2852 o If there is no valid address in the SROM, and a definition in the
2853 environment exists, then the value from the environment variable is
2856 o If both the SROM and the environment contain a MAC address, and
2857 both addresses are the same, this MAC address is used.
2859 o If both the SROM and the environment contain a MAC address, and the
2860 addresses differ, the value from the environment is used and a
2863 o If neither SROM nor the environment contain a MAC address, an error
2870 The "boot" commands of this monitor operate on "image" files which
2871 can be basicly anything, preceeded by a special header; see the
2872 definitions in include/image.h for details; basicly, the header
2873 defines the following image properties:
2875 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2876 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2877 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2878 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2879 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2880 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2881 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2882 * Compression Type (uncompressed, gzip, bzip2)
2888 The header is marked by a special Magic Number, and both the header
2889 and the data portions of the image are secured against corruption by
2896 Although U-Boot should support any OS or standalone application
2897 easily, the main focus has always been on Linux during the design of
2900 U-Boot includes many features that so far have been part of some
2901 special "boot loader" code within the Linux kernel. Also, any
2902 "initrd" images to be used are no longer part of one big Linux image;
2903 instead, kernel and "initrd" are separate images. This implementation
2904 serves several purposes:
2906 - the same features can be used for other OS or standalone
2907 applications (for instance: using compressed images to reduce the
2908 Flash memory footprint)
2910 - it becomes much easier to port new Linux kernel versions because
2911 lots of low-level, hardware dependent stuff are done by U-Boot
2913 - the same Linux kernel image can now be used with different "initrd"
2914 images; of course this also means that different kernel images can
2915 be run with the same "initrd". This makes testing easier (you don't
2916 have to build a new "zImage.initrd" Linux image when you just
2917 change a file in your "initrd"). Also, a field-upgrade of the
2918 software is easier now.
2924 Porting Linux to U-Boot based systems:
2925 ---------------------------------------
2927 U-Boot cannot save you from doing all the necessary modifications to
2928 configure the Linux device drivers for use with your target hardware
2929 (no, we don't intend to provide a full virtual machine interface to
2932 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2934 Just make sure your machine specific header file (for instance
2935 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2936 Information structure as we define in include/u-boot.h, and make
2937 sure that your definition of IMAP_ADDR uses the same value as your
2938 U-Boot configuration in CFG_IMMR.
2941 Configuring the Linux kernel:
2942 -----------------------------
2944 No specific requirements for U-Boot. Make sure you have some root
2945 device (initial ramdisk, NFS) for your target system.
2948 Building a Linux Image:
2949 -----------------------
2951 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2952 not used. If you use recent kernel source, a new build target
2953 "uImage" will exist which automatically builds an image usable by
2954 U-Boot. Most older kernels also have support for a "pImage" target,
2955 which was introduced for our predecessor project PPCBoot and uses a
2956 100% compatible format.
2965 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2966 encapsulate a compressed Linux kernel image with header information,
2967 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2969 * build a standard "vmlinux" kernel image (in ELF binary format):
2971 * convert the kernel into a raw binary image:
2973 ${CROSS_COMPILE}-objcopy -O binary \
2974 -R .note -R .comment \
2975 -S vmlinux linux.bin
2977 * compress the binary image:
2981 * package compressed binary image for U-Boot:
2983 mkimage -A ppc -O linux -T kernel -C gzip \
2984 -a 0 -e 0 -n "Linux Kernel Image" \
2985 -d linux.bin.gz uImage
2988 The "mkimage" tool can also be used to create ramdisk images for use
2989 with U-Boot, either separated from the Linux kernel image, or
2990 combined into one file. "mkimage" encapsulates the images with a 64
2991 byte header containing information about target architecture,
2992 operating system, image type, compression method, entry points, time
2993 stamp, CRC32 checksums, etc.
2995 "mkimage" can be called in two ways: to verify existing images and
2996 print the header information, or to build new images.
2998 In the first form (with "-l" option) mkimage lists the information
2999 contained in the header of an existing U-Boot image; this includes
3000 checksum verification:
3002 tools/mkimage -l image
3003 -l ==> list image header information
3005 The second form (with "-d" option) is used to build a U-Boot image
3006 from a "data file" which is used as image payload:
3008 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3009 -n name -d data_file image
3010 -A ==> set architecture to 'arch'
3011 -O ==> set operating system to 'os'
3012 -T ==> set image type to 'type'
3013 -C ==> set compression type 'comp'
3014 -a ==> set load address to 'addr' (hex)
3015 -e ==> set entry point to 'ep' (hex)
3016 -n ==> set image name to 'name'
3017 -d ==> use image data from 'datafile'
3019 Right now, all Linux kernels for PowerPC systems use the same load
3020 address (0x00000000), but the entry point address depends on the
3023 - 2.2.x kernels have the entry point at 0x0000000C,
3024 - 2.3.x and later kernels have the entry point at 0x00000000.
3026 So a typical call to build a U-Boot image would read:
3028 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3029 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3030 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3031 > examples/uImage.TQM850L
3032 Image Name: 2.4.4 kernel for TQM850L
3033 Created: Wed Jul 19 02:34:59 2000
3034 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3035 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3036 Load Address: 0x00000000
3037 Entry Point: 0x00000000
3039 To verify the contents of the image (or check for corruption):
3041 -> tools/mkimage -l examples/uImage.TQM850L
3042 Image Name: 2.4.4 kernel for TQM850L
3043 Created: Wed Jul 19 02:34:59 2000
3044 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3045 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3046 Load Address: 0x00000000
3047 Entry Point: 0x00000000
3049 NOTE: for embedded systems where boot time is critical you can trade
3050 speed for memory and install an UNCOMPRESSED image instead: this
3051 needs more space in Flash, but boots much faster since it does not
3052 need to be uncompressed:
3054 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3055 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3056 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3057 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3058 > examples/uImage.TQM850L-uncompressed
3059 Image Name: 2.4.4 kernel for TQM850L
3060 Created: Wed Jul 19 02:34:59 2000
3061 Image Type: PowerPC Linux Kernel Image (uncompressed)
3062 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3063 Load Address: 0x00000000
3064 Entry Point: 0x00000000
3067 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3068 when your kernel is intended to use an initial ramdisk:
3070 -> tools/mkimage -n 'Simple Ramdisk Image' \
3071 > -A ppc -O linux -T ramdisk -C gzip \
3072 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3073 Image Name: Simple Ramdisk Image
3074 Created: Wed Jan 12 14:01:50 2000
3075 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3076 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3077 Load Address: 0x00000000
3078 Entry Point: 0x00000000
3081 Installing a Linux Image:
3082 -------------------------
3084 To downloading a U-Boot image over the serial (console) interface,
3085 you must convert the image to S-Record format:
3087 objcopy -I binary -O srec examples/image examples/image.srec
3089 The 'objcopy' does not understand the information in the U-Boot
3090 image header, so the resulting S-Record file will be relative to
3091 address 0x00000000. To load it to a given address, you need to
3092 specify the target address as 'offset' parameter with the 'loads'
3095 Example: install the image to address 0x40100000 (which on the
3096 TQM8xxL is in the first Flash bank):
3098 => erase 40100000 401FFFFF
3104 ## Ready for S-Record download ...
3105 ~>examples/image.srec
3106 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3108 15989 15990 15991 15992
3109 [file transfer complete]
3111 ## Start Addr = 0x00000000
3114 You can check the success of the download using the 'iminfo' command;
3115 this includes a checksum verification so you can be sure no data
3116 corruption happened:
3120 ## Checking Image at 40100000 ...
3121 Image Name: 2.2.13 for initrd on TQM850L
3122 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3123 Data Size: 335725 Bytes = 327 kB = 0 MB
3124 Load Address: 00000000
3125 Entry Point: 0000000c
3126 Verifying Checksum ... OK
3132 The "bootm" command is used to boot an application that is stored in
3133 memory (RAM or Flash). In case of a Linux kernel image, the contents
3134 of the "bootargs" environment variable is passed to the kernel as
3135 parameters. You can check and modify this variable using the
3136 "printenv" and "setenv" commands:
3139 => printenv bootargs
3140 bootargs=root=/dev/ram
3142 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3144 => printenv bootargs
3145 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3148 ## Booting Linux kernel at 40020000 ...
3149 Image Name: 2.2.13 for NFS on TQM850L
3150 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3151 Data Size: 381681 Bytes = 372 kB = 0 MB
3152 Load Address: 00000000
3153 Entry Point: 0000000c
3154 Verifying Checksum ... OK
3155 Uncompressing Kernel Image ... OK
3156 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
3157 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3158 time_init: decrementer frequency = 187500000/60
3159 Calibrating delay loop... 49.77 BogoMIPS
3160 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3163 If you want to boot a Linux kernel with initial ram disk, you pass
3164 the memory addresses of both the kernel and the initrd image (PPBCOOT
3165 format!) to the "bootm" command:
3167 => imi 40100000 40200000
3169 ## Checking Image at 40100000 ...
3170 Image Name: 2.2.13 for initrd on TQM850L
3171 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3172 Data Size: 335725 Bytes = 327 kB = 0 MB
3173 Load Address: 00000000
3174 Entry Point: 0000000c
3175 Verifying Checksum ... OK
3177 ## Checking Image at 40200000 ...
3178 Image Name: Simple Ramdisk Image
3179 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3180 Data Size: 566530 Bytes = 553 kB = 0 MB
3181 Load Address: 00000000
3182 Entry Point: 00000000
3183 Verifying Checksum ... OK
3185 => bootm 40100000 40200000
3186 ## Booting Linux kernel at 40100000 ...
3187 Image Name: 2.2.13 for initrd on TQM850L
3188 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3189 Data Size: 335725 Bytes = 327 kB = 0 MB
3190 Load Address: 00000000
3191 Entry Point: 0000000c
3192 Verifying Checksum ... OK
3193 Uncompressing Kernel Image ... OK
3194 ## Loading RAMDisk Image at 40200000 ...
3195 Image Name: Simple Ramdisk Image
3196 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3197 Data Size: 566530 Bytes = 553 kB = 0 MB
3198 Load Address: 00000000
3199 Entry Point: 00000000
3200 Verifying Checksum ... OK
3201 Loading Ramdisk ... OK
3202 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
3203 Boot arguments: root=/dev/ram
3204 time_init: decrementer frequency = 187500000/60
3205 Calibrating delay loop... 49.77 BogoMIPS
3207 RAMDISK: Compressed image found at block 0
3208 VFS: Mounted root (ext2 filesystem).
3212 Boot Linux and pass a flat device tree:
3215 First, U-Boot must be compiled with the appropriate defines. See the section
3216 titled "Linux Kernel Interface" above for a more in depth explanation. The
3217 following is an example of how to start a kernel and pass an updated
3223 oft=oftrees/mpc8540ads.dtb
3224 => tftp $oftaddr $oft
3225 Speed: 1000, full duplex
3227 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3228 Filename 'oftrees/mpc8540ads.dtb'.
3229 Load address: 0x300000
3232 Bytes transferred = 4106 (100a hex)
3233 => tftp $loadaddr $bootfile
3234 Speed: 1000, full duplex
3236 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3238 Load address: 0x200000
3239 Loading:############
3241 Bytes transferred = 1029407 (fb51f hex)
3246 => bootm $loadaddr - $oftaddr
3247 ## Booting image at 00200000 ...
3248 Image Name: Linux-2.6.17-dirty
3249 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3250 Data Size: 1029343 Bytes = 1005.2 kB
3251 Load Address: 00000000
3252 Entry Point: 00000000
3253 Verifying Checksum ... OK
3254 Uncompressing Kernel Image ... OK
3255 Booting using flat device tree at 0x300000
3256 Using MPC85xx ADS machine description
3257 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3261 More About U-Boot Image Types:
3262 ------------------------------
3264 U-Boot supports the following image types:
3266 "Standalone Programs" are directly runnable in the environment
3267 provided by U-Boot; it is expected that (if they behave
3268 well) you can continue to work in U-Boot after return from
3269 the Standalone Program.
3270 "OS Kernel Images" are usually images of some Embedded OS which
3271 will take over control completely. Usually these programs
3272 will install their own set of exception handlers, device
3273 drivers, set up the MMU, etc. - this means, that you cannot
3274 expect to re-enter U-Boot except by resetting the CPU.
3275 "RAMDisk Images" are more or less just data blocks, and their
3276 parameters (address, size) are passed to an OS kernel that is
3278 "Multi-File Images" contain several images, typically an OS
3279 (Linux) kernel image and one or more data images like
3280 RAMDisks. This construct is useful for instance when you want
3281 to boot over the network using BOOTP etc., where the boot
3282 server provides just a single image file, but you want to get
3283 for instance an OS kernel and a RAMDisk image.
3285 "Multi-File Images" start with a list of image sizes, each
3286 image size (in bytes) specified by an "uint32_t" in network
3287 byte order. This list is terminated by an "(uint32_t)0".
3288 Immediately after the terminating 0 follow the images, one by
3289 one, all aligned on "uint32_t" boundaries (size rounded up to
3290 a multiple of 4 bytes).
3292 "Firmware Images" are binary images containing firmware (like
3293 U-Boot or FPGA images) which usually will be programmed to
3296 "Script files" are command sequences that will be executed by
3297 U-Boot's command interpreter; this feature is especially
3298 useful when you configure U-Boot to use a real shell (hush)
3299 as command interpreter.
3305 One of the features of U-Boot is that you can dynamically load and
3306 run "standalone" applications, which can use some resources of
3307 U-Boot like console I/O functions or interrupt services.
3309 Two simple examples are included with the sources:
3314 'examples/hello_world.c' contains a small "Hello World" Demo
3315 application; it is automatically compiled when you build U-Boot.
3316 It's configured to run at address 0x00040004, so you can play with it
3320 ## Ready for S-Record download ...
3321 ~>examples/hello_world.srec
3322 1 2 3 4 5 6 7 8 9 10 11 ...
3323 [file transfer complete]
3325 ## Start Addr = 0x00040004
3327 => go 40004 Hello World! This is a test.
3328 ## Starting application at 0x00040004 ...
3339 Hit any key to exit ...
3341 ## Application terminated, rc = 0x0
3343 Another example, which demonstrates how to register a CPM interrupt
3344 handler with the U-Boot code, can be found in 'examples/timer.c'.
3345 Here, a CPM timer is set up to generate an interrupt every second.
3346 The interrupt service routine is trivial, just printing a '.'
3347 character, but this is just a demo program. The application can be
3348 controlled by the following keys:
3350 ? - print current values og the CPM Timer registers
3351 b - enable interrupts and start timer
3352 e - stop timer and disable interrupts
3353 q - quit application
3356 ## Ready for S-Record download ...
3357 ~>examples/timer.srec
3358 1 2 3 4 5 6 7 8 9 10 11 ...
3359 [file transfer complete]
3361 ## Start Addr = 0x00040004
3364 ## Starting application at 0x00040004 ...
3367 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3370 [q, b, e, ?] Set interval 1000000 us
3373 [q, b, e, ?] ........
3374 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3377 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3380 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3383 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3385 [q, b, e, ?] ...Stopping timer
3387 [q, b, e, ?] ## Application terminated, rc = 0x0
3393 Over time, many people have reported problems when trying to use the
3394 "minicom" terminal emulation program for serial download. I (wd)
3395 consider minicom to be broken, and recommend not to use it. Under
3396 Unix, I recommend to use C-Kermit for general purpose use (and
3397 especially for kermit binary protocol download ("loadb" command), and
3398 use "cu" for S-Record download ("loads" command).
3400 Nevertheless, if you absolutely want to use it try adding this
3401 configuration to your "File transfer protocols" section:
3403 Name Program Name U/D FullScr IO-Red. Multi
3404 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3405 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3411 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3412 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3414 Building requires a cross environment; it is known to work on
3415 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3416 need gmake since the Makefiles are not compatible with BSD make).
3417 Note that the cross-powerpc package does not install include files;
3418 attempting to build U-Boot will fail because <machine/ansi.h> is
3419 missing. This file has to be installed and patched manually:
3421 # cd /usr/pkg/cross/powerpc-netbsd/include
3423 # ln -s powerpc machine
3424 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3425 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3427 Native builds *don't* work due to incompatibilities between native
3428 and U-Boot include files.
3430 Booting assumes that (the first part of) the image booted is a
3431 stage-2 loader which in turn loads and then invokes the kernel
3432 proper. Loader sources will eventually appear in the NetBSD source
3433 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3434 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3437 Implementation Internals:
3438 =========================
3440 The following is not intended to be a complete description of every
3441 implementation detail. However, it should help to understand the
3442 inner workings of U-Boot and make it easier to port it to custom
3446 Initial Stack, Global Data:
3447 ---------------------------
3449 The implementation of U-Boot is complicated by the fact that U-Boot
3450 starts running out of ROM (flash memory), usually without access to
3451 system RAM (because the memory controller is not initialized yet).
3452 This means that we don't have writable Data or BSS segments, and BSS
3453 is not initialized as zero. To be able to get a C environment working
3454 at all, we have to allocate at least a minimal stack. Implementation
3455 options for this are defined and restricted by the CPU used: Some CPU
3456 models provide on-chip memory (like the IMMR area on MPC8xx and
3457 MPC826x processors), on others (parts of) the data cache can be
3458 locked as (mis-) used as memory, etc.
3460 Chris Hallinan posted a good summary of these issues to the
3461 u-boot-users mailing list:
3463 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3464 From: "Chris Hallinan" <clh@net1plus.com>
3465 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3468 Correct me if I'm wrong, folks, but the way I understand it
3469 is this: Using DCACHE as initial RAM for Stack, etc, does not
3470 require any physical RAM backing up the cache. The cleverness
3471 is that the cache is being used as a temporary supply of
3472 necessary storage before the SDRAM controller is setup. It's
3473 beyond the scope of this list to expain the details, but you
3474 can see how this works by studying the cache architecture and
3475 operation in the architecture and processor-specific manuals.
3477 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3478 is another option for the system designer to use as an
3479 initial stack/ram area prior to SDRAM being available. Either
3480 option should work for you. Using CS 4 should be fine if your
3481 board designers haven't used it for something that would
3482 cause you grief during the initial boot! It is frequently not
3485 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3486 with your processor/board/system design. The default value
3487 you will find in any recent u-boot distribution in
3488 walnut.h should work for you. I'd set it to a value larger
3489 than your SDRAM module. If you have a 64MB SDRAM module, set
3490 it above 400_0000. Just make sure your board has no resources
3491 that are supposed to respond to that address! That code in
3492 start.S has been around a while and should work as is when
3493 you get the config right.
3498 It is essential to remember this, since it has some impact on the C
3499 code for the initialization procedures:
3501 * Initialized global data (data segment) is read-only. Do not attempt
3504 * Do not use any unitialized global data (or implicitely initialized
3505 as zero data - BSS segment) at all - this is undefined, initiali-
3506 zation is performed later (when relocating to RAM).
3508 * Stack space is very limited. Avoid big data buffers or things like
3511 Having only the stack as writable memory limits means we cannot use
3512 normal global data to share information beween the code. But it
3513 turned out that the implementation of U-Boot can be greatly
3514 simplified by making a global data structure (gd_t) available to all
3515 functions. We could pass a pointer to this data as argument to _all_
3516 functions, but this would bloat the code. Instead we use a feature of
3517 the GCC compiler (Global Register Variables) to share the data: we
3518 place a pointer (gd) to the global data into a register which we
3519 reserve for this purpose.
3521 When choosing a register for such a purpose we are restricted by the
3522 relevant (E)ABI specifications for the current architecture, and by
3523 GCC's implementation.
3525 For PowerPC, the following registers have specific use:
3528 R3-R4: parameter passing and return values
3529 R5-R10: parameter passing
3530 R13: small data area pointer
3534 (U-Boot also uses R14 as internal GOT pointer.)
3536 ==> U-Boot will use R29 to hold a pointer to the global data
3538 Note: on PPC, we could use a static initializer (since the
3539 address of the global data structure is known at compile time),
3540 but it turned out that reserving a register results in somewhat
3541 smaller code - although the code savings are not that big (on
3542 average for all boards 752 bytes for the whole U-Boot image,
3543 624 text + 127 data).
3545 On ARM, the following registers are used:
3547 R0: function argument word/integer result
3548 R1-R3: function argument word
3550 R10: stack limit (used only if stack checking if enabled)
3551 R11: argument (frame) pointer
3552 R12: temporary workspace
3555 R15: program counter
3557 ==> U-Boot will use R8 to hold a pointer to the global data
3559 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3560 or current versions of GCC may "optimize" the code too much.
3565 U-Boot runs in system state and uses physical addresses, i.e. the
3566 MMU is not used either for address mapping nor for memory protection.
3568 The available memory is mapped to fixed addresses using the memory
3569 controller. In this process, a contiguous block is formed for each
3570 memory type (Flash, SDRAM, SRAM), even when it consists of several
3571 physical memory banks.
3573 U-Boot is installed in the first 128 kB of the first Flash bank (on
3574 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3575 booting and sizing and initializing DRAM, the code relocates itself
3576 to the upper end of DRAM. Immediately below the U-Boot code some
3577 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3578 configuration setting]. Below that, a structure with global Board
3579 Info data is placed, followed by the stack (growing downward).
3581 Additionally, some exception handler code is copied to the low 8 kB
3582 of DRAM (0x00000000 ... 0x00001FFF).
3584 So a typical memory configuration with 16 MB of DRAM could look like
3587 0x0000 0000 Exception Vector code
3590 0x0000 2000 Free for Application Use
3596 0x00FB FF20 Monitor Stack (Growing downward)
3597 0x00FB FFAC Board Info Data and permanent copy of global data
3598 0x00FC 0000 Malloc Arena
3601 0x00FE 0000 RAM Copy of Monitor Code
3602 ... eventually: LCD or video framebuffer
3603 ... eventually: pRAM (Protected RAM - unchanged by reset)
3604 0x00FF FFFF [End of RAM]
3607 System Initialization:
3608 ----------------------
3610 In the reset configuration, U-Boot starts at the reset entry point
3611 (on most PowerPC systens at address 0x00000100). Because of the reset
3612 configuration for CS0# this is a mirror of the onboard Flash memory.
3613 To be able to re-map memory U-Boot then jumps to its link address.
3614 To be able to implement the initialization code in C, a (small!)
3615 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3616 which provide such a feature like MPC8xx or MPC8260), or in a locked
3617 part of the data cache. After that, U-Boot initializes the CPU core,
3618 the caches and the SIU.
3620 Next, all (potentially) available memory banks are mapped using a
3621 preliminary mapping. For example, we put them on 512 MB boundaries
3622 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3623 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3624 programmed for SDRAM access. Using the temporary configuration, a
3625 simple memory test is run that determines the size of the SDRAM
3628 When there is more than one SDRAM bank, and the banks are of
3629 different size, the largest is mapped first. For equal size, the first
3630 bank (CS2#) is mapped first. The first mapping is always for address
3631 0x00000000, with any additional banks following immediately to create
3632 contiguous memory starting from 0.
3634 Then, the monitor installs itself at the upper end of the SDRAM area
3635 and allocates memory for use by malloc() and for the global Board
3636 Info data; also, the exception vector code is copied to the low RAM
3637 pages, and the final stack is set up.
3639 Only after this relocation will you have a "normal" C environment;
3640 until that you are restricted in several ways, mostly because you are
3641 running from ROM, and because the code will have to be relocated to a
3645 U-Boot Porting Guide:
3646 ----------------------
3648 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3652 int main (int argc, char *argv[])
3654 sighandler_t no_more_time;
3656 signal (SIGALRM, no_more_time);
3657 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3659 if (available_money > available_manpower) {
3660 pay consultant to port U-Boot;
3664 Download latest U-Boot source;
3666 Subscribe to u-boot-users mailing list;
3669 email ("Hi, I am new to U-Boot, how do I get started?");
3673 Read the README file in the top level directory;
3674 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3675 Read the source, Luke;
3678 if (available_money > toLocalCurrency ($2500)) {
3681 Add a lot of aggravation and time;
3684 Create your own board support subdirectory;
3686 Create your own board config file;
3690 Add / modify source code;
3694 email ("Hi, I am having problems...");
3696 Send patch file to Wolfgang;
3701 void no_more_time (int sig)
3710 All contributions to U-Boot should conform to the Linux kernel
3711 coding style; see the file "Documentation/CodingStyle" and the script
3712 "scripts/Lindent" in your Linux kernel source directory. In sources
3713 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3714 spaces before parameters to function calls) is actually used.
3716 Source files originating from a different project (for example the
3717 MTD subsystem) are generally exempt from these guidelines and are not
3718 reformated to ease subsequent migration to newer versions of those
3721 Please note that U-Boot is implemented in C (and to some small parts in
3722 Assembler); no C++ is used, so please do not use C++ style comments (//)
3725 Please also stick to the following formatting rules:
3726 - remove any trailing white space
3727 - use TAB characters for indentation, not spaces
3728 - make sure NOT to use DOS '\r\n' line feeds
3729 - do not add more than 2 empty lines to source files
3730 - do not add trailing empty lines to source files
3732 Submissions which do not conform to the standards may be returned
3733 with a request to reformat the changes.
3739 Since the number of patches for U-Boot is growing, we need to
3740 establish some rules. Submissions which do not conform to these rules
3741 may be rejected, even when they contain important and valuable stuff.
3743 Patches shall be sent to the u-boot-users mailing list.
3745 When you send a patch, please include the following information with
3748 * For bug fixes: a description of the bug and how your patch fixes
3749 this bug. Please try to include a way of demonstrating that the
3750 patch actually fixes something.
3752 * For new features: a description of the feature and your
3755 * A CHANGELOG entry as plaintext (separate from the patch)
3757 * For major contributions, your entry to the CREDITS file
3759 * When you add support for a new board, don't forget to add this
3760 board to the MAKEALL script, too.
3762 * If your patch adds new configuration options, don't forget to
3763 document these in the README file.
3765 * The patch itself. If you are accessing the CVS repository use "cvs
3766 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3767 version of diff does not support these options, then get the latest
3768 version of GNU diff.
3770 The current directory when running this command shall be the top
3771 level directory of the U-Boot source tree, or it's parent directory
3772 (i. e. please make sure that your patch includes sufficient
3773 directory information for the affected files).
3775 We accept patches as plain text, MIME attachments or as uuencoded
3778 * If one logical set of modifications affects or creates several
3779 files, all these changes shall be submitted in a SINGLE patch file.
3781 * Changesets that contain different, unrelated modifications shall be
3782 submitted as SEPARATE patches, one patch per changeset.
3787 * Before sending the patch, run the MAKEALL script on your patched
3788 source tree and make sure that no errors or warnings are reported
3789 for any of the boards.
3791 * Keep your modifications to the necessary minimum: A patch
3792 containing several unrelated changes or arbitrary reformats will be
3793 returned with a request to re-formatting / split it.
3795 * If you modify existing code, make sure that your new code does not
3796 add to the memory footprint of the code ;-) Small is beautiful!
3797 When adding new features, these should compile conditionally only
3798 (using #ifdef), and the resulting code with the new feature
3799 disabled must not need more memory than the old code without your
3802 * Remember that there is a size limit of 40 kB per message on the
3803 u-boot-users mailing list. Compression may help.
projects / u-boot / blob