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 - i386 Files specific to i386 CPUs
136 - ixp Files specific to Intel XScale IXP CPUs
137 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
138 - mips Files specific to MIPS CPUs
139 - mpc5xx Files specific to Freescale MPC5xx CPUs
140 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
141 - mpc8xx Files specific to Freescale MPC8xx CPUs
142 - mpc8220 Files specific to Freescale MPC8220 CPUs
143 - mpc824x Files specific to Freescale MPC824x CPUs
144 - mpc8260 Files specific to Freescale MPC8260 CPUs
145 - mpc85xx Files specific to Freescale MPC85xx CPUs
146 - nios Files specific to Altera NIOS CPUs
147 - nios2 Files specific to Altera Nios-II CPUs
148 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
149 - pxa Files specific to Intel XScale PXA CPUs
150 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
151 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
152 - disk Code for disk drive partition handling
153 - doc Documentation (don't expect too much)
154 - drivers Commonly used device drivers
155 - dtt Digital Thermometer and Thermostat drivers
156 - examples Example code for standalone applications, etc.
157 - include Header Files
158 - lib_arm Files generic to ARM architecture
159 - lib_generic Files generic to all architectures
160 - lib_i386 Files generic to i386 architecture
161 - lib_m68k Files generic to m68k architecture
162 - lib_mips Files generic to MIPS architecture
163 - lib_nios Files generic to NIOS architecture
164 - lib_ppc Files generic to PowerPC architecture
165 - net Networking code
166 - post Power On Self Test
167 - rtc Real Time Clock drivers
168 - tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Later we will add a configuration tool - probably similar to or even
188 identical to what's used for the Linux kernel. Right now, we have to
189 do the configuration by hand, which means creating some symbolic
190 links and editing some configuration files. We use the TQM8xxL boards
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_config".
200 Example: For a TQM823L module type:
205 For the Cogent platform, you need to specify the cpu type as well;
206 e.g. "make cogent_mpc8xx_config". And also configure the cogent
207 directory according to the instructions in cogent/README.
210 Configuration Options:
211 ----------------------
213 Configuration depends on the combination of board and CPU type; all
214 such information is kept in a configuration file
215 "include/configs/<board_name>.h".
217 Example: For a TQM823L module, all configuration settings are in
218 "include/configs/TQM823L.h".
221 Many of the options are named exactly as the corresponding Linux
222 kernel configuration options. The intention is to make it easier to
223 build a config tool - later.
226 The following options need to be configured:
228 - CPU Type: Define exactly one of
232 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
235 or CONFIG_MPC824X, CONFIG_MPC8260
251 MicroBlaze based CPUs:
252 ----------------------
256 ----------------------
260 - Board Type: Define exactly one of
262 PowerPC based boards:
263 ---------------------
265 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
266 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
267 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
268 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
269 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
270 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
271 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
272 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
273 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
274 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
275 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
276 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
277 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
278 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
279 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
280 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
281 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
282 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
283 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
284 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
285 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
286 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
287 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
288 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
289 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
290 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
291 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
292 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
293 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
294 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
295 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
296 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
297 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
298 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
299 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
300 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
301 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
302 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
307 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
308 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
309 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
310 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
311 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
312 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
313 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
314 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
317 MicroBlaze based boards:
318 ------------------------
323 ------------------------
325 CONFIG_PCI5441 CONFIG_PK1C20
326 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
329 - CPU Module Type: (if CONFIG_COGENT is defined)
330 Define exactly one of
332 --- FIXME --- not tested yet:
333 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
334 CONFIG_CMA287_23, CONFIG_CMA287_50
336 - Motherboard Type: (if CONFIG_COGENT is defined)
337 Define exactly one of
338 CONFIG_CMA101, CONFIG_CMA102
340 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
341 Define one or more of
344 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
345 Define one or more of
346 CONFIG_LCD_HEARTBEAT - update a character position on
347 the lcd display every second with
350 - Board flavour: (if CONFIG_MPC8260ADS is defined)
353 CFG_8260ADS - original MPC8260ADS
354 CFG_8266ADS - MPC8266ADS
355 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
356 CFG_8272ADS - MPC8272ADS
358 - MPC824X Family Member (if CONFIG_MPC824X is defined)
359 Define exactly one of
360 CONFIG_MPC8240, CONFIG_MPC8245
362 - 8xx CPU Options: (if using an MPC8xx cpu)
363 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
364 get_gclk_freq() cannot work
365 e.g. if there is no 32KHz
366 reference PIT/RTC clock
367 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
370 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
373 CONFIG_8xx_CPUCLK_DEFAULT
374 See doc/README.MPC866
378 Define this to measure the actual CPU clock instead
379 of relying on the correctness of the configured
380 values. Mostly useful for board bringup to make sure
381 the PLL is locked at the intended frequency. Note
382 that this requires a (stable) reference clock (32 kHz
383 RTC clock or CFG_8XX_XIN)
385 - Intel Monahans options:
386 CFG_MONAHANS_RUN_MODE_OSC_RATIO
388 Defines the Monahans run mode to oscillator
389 ratio. Valid values are 8, 16, 24, 31. The core
390 frequency is this value multiplied by 13 MHz.
392 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
394 Defines the Monahans turbo mode to oscillator
395 ratio. Valid values are 1 (default if undefined) and
396 2. The core frequency as calculated above is multiplied
399 - Linux Kernel Interface:
402 U-Boot stores all clock information in Hz
403 internally. For binary compatibility with older Linux
404 kernels (which expect the clocks passed in the
405 bd_info data to be in MHz) the environment variable
406 "clocks_in_mhz" can be defined so that U-Boot
407 converts clock data to MHZ before passing it to the
409 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
410 "clocks_in_mhz=1" is automatically included in the
413 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
415 When transfering memsize parameter to linux, some versions
416 expect it to be in bytes, others in MB.
417 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
421 New kernel versions are expecting firmware settings to be
422 passed using flat open firmware trees.
423 The environment variable "disable_of", when set, disables this
426 CONFIG_OF_FLAT_TREE_MAX_SIZE
428 The maximum size of the constructed OF tree.
430 OF_CPU - The proper name of the cpus node.
431 OF_SOC - The proper name of the soc node.
432 OF_TBCLK - The timebase frequency.
433 OF_STDOUT_PATH - The path to the console device
437 The resulting flat device tree will have a copy of the bd_t.
438 Space should be pre-allocated in the dts for the bd_t.
440 CONFIG_OF_HAS_UBOOT_ENV
442 The resulting flat device tree will have a copy of u-boot's
443 environment variables
445 CONFIG_OF_BOARD_SETUP
447 Board code has addition modification that it wants to make
448 to the flat device tree before handing it off to the kernel
453 Define this if you want support for Amba PrimeCell PL010 UARTs.
457 Define this if you want support for Amba PrimeCell PL011 UARTs.
461 If you have Amba PrimeCell PL011 UARTs, set this variable to
462 the clock speed of the UARTs.
466 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
467 define this to a list of base addresses for each (supported)
468 port. See e.g. include/configs/versatile.h
472 Depending on board, define exactly one serial port
473 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
474 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
475 console by defining CONFIG_8xx_CONS_NONE
477 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
478 port routines must be defined elsewhere
479 (i.e. serial_init(), serial_getc(), ...)
482 Enables console device for a color framebuffer. Needs following
483 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
484 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
486 VIDEO_HW_RECTFILL graphic chip supports
489 VIDEO_HW_BITBLT graphic chip supports
490 bit-blit (cf. smiLynxEM)
491 VIDEO_VISIBLE_COLS visible pixel columns
493 VIDEO_VISIBLE_ROWS visible pixel rows
494 VIDEO_PIXEL_SIZE bytes per pixel
495 VIDEO_DATA_FORMAT graphic data format
496 (0-5, cf. cfb_console.c)
497 VIDEO_FB_ADRS framebuffer address
498 VIDEO_KBD_INIT_FCT keyboard int fct
499 (i.e. i8042_kbd_init())
500 VIDEO_TSTC_FCT test char fct
502 VIDEO_GETC_FCT get char fct
504 CONFIG_CONSOLE_CURSOR cursor drawing on/off
505 (requires blink timer
507 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
508 CONFIG_CONSOLE_TIME display time/date info in
510 (requires CFG_CMD_DATE)
511 CONFIG_VIDEO_LOGO display Linux logo in
513 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
514 linux_logo.h for logo.
515 Requires CONFIG_VIDEO_LOGO
516 CONFIG_CONSOLE_EXTRA_INFO
517 addional board info beside
520 When CONFIG_CFB_CONSOLE is defined, video console is
521 default i/o. Serial console can be forced with
522 environment 'console=serial'.
524 When CONFIG_SILENT_CONSOLE is defined, all console
525 messages (by U-Boot and Linux!) can be silenced with
526 the "silent" environment variable. See
527 doc/README.silent for more information.
530 CONFIG_BAUDRATE - in bps
531 Select one of the baudrates listed in
532 CFG_BAUDRATE_TABLE, see below.
533 CFG_BRGCLK_PRESCALE, baudrate prescale
535 - Interrupt driven serial port input:
536 CONFIG_SERIAL_SOFTWARE_FIFO
539 Use an interrupt handler for receiving data on the
540 serial port. It also enables using hardware handshake
541 (RTS/CTS) and UART's built-in FIFO. Set the number of
542 bytes the interrupt driven input buffer should have.
544 Leave undefined to disable this feature, including
545 disable the buffer and hardware handshake.
547 - Console UART Number:
551 If defined internal UART1 (and not UART0) is used
552 as default U-Boot console.
554 - Boot Delay: CONFIG_BOOTDELAY - in seconds
555 Delay before automatically booting the default image;
556 set to -1 to disable autoboot.
558 See doc/README.autoboot for these options that
559 work with CONFIG_BOOTDELAY. None are required.
560 CONFIG_BOOT_RETRY_TIME
561 CONFIG_BOOT_RETRY_MIN
562 CONFIG_AUTOBOOT_KEYED
563 CONFIG_AUTOBOOT_PROMPT
564 CONFIG_AUTOBOOT_DELAY_STR
565 CONFIG_AUTOBOOT_STOP_STR
566 CONFIG_AUTOBOOT_DELAY_STR2
567 CONFIG_AUTOBOOT_STOP_STR2
568 CONFIG_ZERO_BOOTDELAY_CHECK
569 CONFIG_RESET_TO_RETRY
573 Only needed when CONFIG_BOOTDELAY is enabled;
574 define a command string that is automatically executed
575 when no character is read on the console interface
576 within "Boot Delay" after reset.
579 This can be used to pass arguments to the bootm
580 command. The value of CONFIG_BOOTARGS goes into the
581 environment value "bootargs".
583 CONFIG_RAMBOOT and CONFIG_NFSBOOT
584 The value of these goes into the environment as
585 "ramboot" and "nfsboot" respectively, and can be used
586 as a convenience, when switching between booting from
592 When this option is #defined, the existence of the
593 environment variable "preboot" will be checked
594 immediately before starting the CONFIG_BOOTDELAY
595 countdown and/or running the auto-boot command resp.
596 entering interactive mode.
598 This feature is especially useful when "preboot" is
599 automatically generated or modified. For an example
600 see the LWMON board specific code: here "preboot" is
601 modified when the user holds down a certain
602 combination of keys on the (special) keyboard when
605 - Serial Download Echo Mode:
607 If defined to 1, all characters received during a
608 serial download (using the "loads" command) are
609 echoed back. This might be needed by some terminal
610 emulations (like "cu"), but may as well just take
611 time on others. This setting #define's the initial
612 value of the "loads_echo" environment variable.
614 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
616 Select one of the baudrates listed in
617 CFG_BAUDRATE_TABLE, see below.
621 Most monitor functions can be selected (or
622 de-selected) by adjusting the definition of
623 CONFIG_COMMANDS; to select individual functions,
624 #define CONFIG_COMMANDS by "OR"ing any of the
627 #define enables commands:
628 -------------------------
629 CFG_CMD_ASKENV * ask for env variable
630 CFG_CMD_AUTOSCRIPT Autoscript Support
632 CFG_CMD_BEDBUG * Include BedBug Debugger
633 CFG_CMD_BMP * BMP support
634 CFG_CMD_BSP * Board specific commands
636 CFG_CMD_CACHE * icache, dcache
637 CFG_CMD_CONSOLE coninfo
638 CFG_CMD_DATE * support for RTC, date/time...
639 CFG_CMD_DHCP * DHCP support
640 CFG_CMD_DIAG * Diagnostics
641 CFG_CMD_DOC * Disk-On-Chip Support
642 CFG_CMD_DTT * Digital Therm and Thermostat
643 CFG_CMD_ECHO echo arguments
644 CFG_CMD_EEPROM * EEPROM read/write support
645 CFG_CMD_ELF * bootelf, bootvx
647 CFG_CMD_FDC * Floppy Disk Support
648 CFG_CMD_FAT * FAT partition support
649 CFG_CMD_FDOS * Dos diskette Support
650 CFG_CMD_FLASH flinfo, erase, protect
651 CFG_CMD_FPGA FPGA device initialization support
652 CFG_CMD_HWFLOW * RTS/CTS hw flow control
653 CFG_CMD_I2C * I2C serial bus support
654 CFG_CMD_IDE * IDE harddisk support
656 CFG_CMD_IMLS List all found images
657 CFG_CMD_IMMAP * IMMR dump support
658 CFG_CMD_IRQ * irqinfo
659 CFG_CMD_ITEST Integer/string test of 2 values
660 CFG_CMD_JFFS2 * JFFS2 Support
664 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
666 CFG_CMD_MISC Misc functions like sleep etc
667 CFG_CMD_MMC * MMC memory mapped support
668 CFG_CMD_MII * MII utility commands
669 CFG_CMD_NAND * NAND support
670 CFG_CMD_NET bootp, tftpboot, rarpboot
671 CFG_CMD_PCI * pciinfo
672 CFG_CMD_PCMCIA * PCMCIA support
673 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
674 CFG_CMD_PORTIO * Port I/O
675 CFG_CMD_REGINFO * Register dump
676 CFG_CMD_RUN run command in env variable
677 CFG_CMD_SAVES * save S record dump
678 CFG_CMD_SCSI * SCSI Support
679 CFG_CMD_SDRAM * print SDRAM configuration information
680 (requires CFG_CMD_I2C)
681 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
682 CFG_CMD_SPI * SPI serial bus support
683 CFG_CMD_USB * USB support
684 CFG_CMD_VFD * VFD support (TRAB)
685 CFG_CMD_BSP * Board SPecific functions
686 CFG_CMD_CDP * Cisco Discover Protocol support
687 -----------------------------------------------
690 CONFIG_CMD_DFL Default configuration; at the moment
691 this is includes all commands, except
692 the ones marked with "*" in the list
695 If you don't define CONFIG_COMMANDS it defaults to
696 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
697 override the default settings in the respective
700 EXAMPLE: If you want all functions except of network
701 support you can write:
703 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
706 Note: Don't enable the "icache" and "dcache" commands
707 (configuration option CFG_CMD_CACHE) unless you know
708 what you (and your U-Boot users) are doing. Data
709 cache cannot be enabled on systems like the 8xx or
710 8260 (where accesses to the IMMR region must be
711 uncached), and it cannot be disabled on all other
712 systems where we (mis-) use the data cache to hold an
713 initial stack and some data.
716 XXX - this list needs to get updated!
720 If this variable is defined, it enables watchdog
721 support. There must be support in the platform specific
722 code for a watchdog. For the 8xx and 8260 CPUs, the
723 SIU Watchdog feature is enabled in the SYPCR
727 CONFIG_VERSION_VARIABLE
728 If this variable is defined, an environment variable
729 named "ver" is created by U-Boot showing the U-Boot
730 version as printed by the "version" command.
731 This variable is readonly.
735 When CFG_CMD_DATE is selected, the type of the RTC
736 has to be selected, too. Define exactly one of the
739 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
740 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
741 CONFIG_RTC_MC146818 - use MC146818 RTC
742 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
743 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
744 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
745 CONFIG_RTC_DS164x - use Dallas DS164x RTC
746 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
748 Note that if the RTC uses I2C, then the I2C interface
749 must also be configured. See I2C Support, below.
753 When CONFIG_TIMESTAMP is selected, the timestamp
754 (date and time) of an image is printed by image
755 commands like bootm or iminfo. This option is
756 automatically enabled when you select CFG_CMD_DATE .
759 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
760 and/or CONFIG_ISO_PARTITION
762 If IDE or SCSI support is enabled (CFG_CMD_IDE or
763 CFG_CMD_SCSI) you must configure support for at least
764 one partition type as well.
767 CONFIG_IDE_RESET_ROUTINE - this is defined in several
768 board configurations files but used nowhere!
770 CONFIG_IDE_RESET - is this is defined, IDE Reset will
771 be performed by calling the function
772 ide_set_reset(int reset)
773 which has to be defined in a board specific file
778 Set this to enable ATAPI support.
783 Set this to enable support for disks larger than 137GB
784 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
785 Whithout these , LBA48 support uses 32bit variables and will 'only'
786 support disks up to 2.1TB.
789 When enabled, makes the IDE subsystem use 64bit sector addresses.
793 At the moment only there is only support for the
794 SYM53C8XX SCSI controller; define
795 CONFIG_SCSI_SYM53C8XX to enable it.
797 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
798 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
799 CFG_SCSI_MAX_LUN] can be adjusted to define the
800 maximum numbers of LUNs, SCSI ID's and target
802 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
804 - NETWORK Support (PCI):
806 Support for Intel 8254x gigabit chips.
809 Support for Intel 82557/82559/82559ER chips.
810 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
811 write routine for first time initialisation.
814 Support for Digital 2114x chips.
815 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
816 modem chip initialisation (KS8761/QS6611).
819 Support for National dp83815 chips.
822 Support for National dp8382[01] gigabit chips.
824 - NETWORK Support (other):
826 CONFIG_DRIVER_LAN91C96
827 Support for SMSC's LAN91C96 chips.
830 Define this to hold the physical address
831 of the LAN91C96's I/O space
833 CONFIG_LAN91C96_USE_32_BIT
834 Define this to enable 32 bit addressing
836 CONFIG_DRIVER_SMC91111
837 Support for SMSC's LAN91C111 chip
840 Define this to hold the physical address
841 of the device (I/O space)
843 CONFIG_SMC_USE_32_BIT
844 Define this if data bus is 32 bits
846 CONFIG_SMC_USE_IOFUNCS
847 Define this to use i/o functions instead of macros
848 (some hardware wont work with macros)
851 At the moment only the UHCI host controller is
852 supported (PIP405, MIP405, MPC5200); define
853 CONFIG_USB_UHCI to enable it.
854 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
855 and define CONFIG_USB_STORAGE to enable the USB
858 Supported are USB Keyboards and USB Floppy drives
860 MPC5200 USB requires additional defines:
862 for 528 MHz Clock: 0x0001bbbb
864 for differential drivers: 0x00001000
865 for single ended drivers: 0x00005000
869 The MMC controller on the Intel PXA is supported. To
870 enable this define CONFIG_MMC. The MMC can be
871 accessed from the boot prompt by mapping the device
872 to physical memory similar to flash. Command line is
873 enabled with CFG_CMD_MMC. The MMC driver also works with
874 the FAT fs. This is enabled with CFG_CMD_FAT.
876 - Journaling Flash filesystem support:
877 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
878 CONFIG_JFFS2_NAND_DEV
879 Define these for a default partition on a NAND device
881 CFG_JFFS2_FIRST_SECTOR,
882 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
883 Define these for a default partition on a NOR device
886 Define this to create an own partition. You have to provide a
887 function struct part_info* jffs2_part_info(int part_num)
889 If you define only one JFFS2 partition you may also want to
890 #define CFG_JFFS_SINGLE_PART 1
891 to disable the command chpart. This is the default when you
892 have not defined a custom partition
897 Define this to enable standard (PC-Style) keyboard
901 Standard PC keyboard driver with US (is default) and
902 GERMAN key layout (switch via environment 'keymap=de') support.
903 Export function i8042_kbd_init, i8042_tstc and i8042_getc
904 for cfb_console. Supports cursor blinking.
909 Define this to enable video support (for output to
914 Enable Chips & Technologies 69000 Video chip
916 CONFIG_VIDEO_SMI_LYNXEM
917 Enable Silicon Motion SMI 712/710/810 Video chip. The
918 video output is selected via environment 'videoout'
919 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
922 For the CT69000 and SMI_LYNXEM drivers, videomode is
923 selected via environment 'videomode'. Two diferent ways
925 - "videomode=num" 'num' is a standard LiLo mode numbers.
926 Following standard modes are supported (* is default):
928 Colors 640x480 800x600 1024x768 1152x864 1280x1024
929 -------------+---------------------------------------------
930 8 bits | 0x301* 0x303 0x305 0x161 0x307
931 15 bits | 0x310 0x313 0x316 0x162 0x319
932 16 bits | 0x311 0x314 0x317 0x163 0x31A
933 24 bits | 0x312 0x315 0x318 ? 0x31B
934 -------------+---------------------------------------------
935 (i.e. setenv videomode 317; saveenv; reset;)
937 - "videomode=bootargs" all the video parameters are parsed
938 from the bootargs. (See drivers/videomodes.c)
941 CONFIG_VIDEO_SED13806
942 Enable Epson SED13806 driver. This driver supports 8bpp
943 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
944 or CONFIG_VIDEO_SED13806_16BPP
949 Define this to enable a custom keyboard support.
950 This simply calls drv_keyboard_init() which must be
951 defined in your board-specific files.
952 The only board using this so far is RBC823.
954 - LCD Support: CONFIG_LCD
956 Define this to enable LCD support (for output to LCD
957 display); also select one of the supported displays
958 by defining one of these:
960 CONFIG_NEC_NL6448AC33:
962 NEC NL6448AC33-18. Active, color, single scan.
964 CONFIG_NEC_NL6448BC20
966 NEC NL6448BC20-08. 6.5", 640x480.
967 Active, color, single scan.
969 CONFIG_NEC_NL6448BC33_54
971 NEC NL6448BC33-54. 10.4", 640x480.
972 Active, color, single scan.
976 Sharp 320x240. Active, color, single scan.
977 It isn't 16x9, and I am not sure what it is.
979 CONFIG_SHARP_LQ64D341
981 Sharp LQ64D341 display, 640x480.
982 Active, color, single scan.
986 HLD1045 display, 640x480.
987 Active, color, single scan.
991 Optrex CBL50840-2 NF-FW 99 22 M5
993 Hitachi LMG6912RPFC-00T
997 320x240. Black & white.
999 Normally display is black on white background; define
1000 CFG_WHITE_ON_BLACK to get it inverted.
1002 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1004 If this option is set, the environment is checked for
1005 a variable "splashimage". If found, the usual display
1006 of logo, copyright and system information on the LCD
1007 is suppressed and the BMP image at the address
1008 specified in "splashimage" is loaded instead. The
1009 console is redirected to the "nulldev", too. This
1010 allows for a "silent" boot where a splash screen is
1011 loaded very quickly after power-on.
1013 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1015 If this option is set, additionally to standard BMP
1016 images, gzipped BMP images can be displayed via the
1017 splashscreen support or the bmp command.
1019 - Compression support:
1022 If this option is set, support for bzip2 compressed
1023 images is included. If not, only uncompressed and gzip
1024 compressed images are supported.
1026 NOTE: the bzip2 algorithm requires a lot of RAM, so
1027 the malloc area (as defined by CFG_MALLOC_LEN) should
1033 The address of PHY on MII bus.
1035 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1037 The clock frequency of the MII bus
1041 If this option is set, support for speed/duplex
1042 detection of Gigabit PHY is included.
1044 CONFIG_PHY_RESET_DELAY
1046 Some PHY like Intel LXT971A need extra delay after
1047 reset before any MII register access is possible.
1048 For such PHY, set this option to the usec delay
1049 required. (minimum 300usec for LXT971A)
1051 CONFIG_PHY_CMD_DELAY (ppc4xx)
1053 Some PHY like Intel LXT971A need extra delay after
1054 command issued before MII status register can be read
1061 Define a default value for ethernet address to use
1062 for the respective ethernet interface, in case this
1063 is not determined automatically.
1068 Define a default value for the IP address to use for
1069 the default ethernet interface, in case this is not
1070 determined through e.g. bootp.
1072 - Server IP address:
1075 Defines a default value for theIP address of a TFTP
1076 server to contact when using the "tftboot" command.
1078 - BOOTP Recovery Mode:
1079 CONFIG_BOOTP_RANDOM_DELAY
1081 If you have many targets in a network that try to
1082 boot using BOOTP, you may want to avoid that all
1083 systems send out BOOTP requests at precisely the same
1084 moment (which would happen for instance at recovery
1085 from a power failure, when all systems will try to
1086 boot, thus flooding the BOOTP server. Defining
1087 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1088 inserted before sending out BOOTP requests. The
1089 following delays are insterted then:
1091 1st BOOTP request: delay 0 ... 1 sec
1092 2nd BOOTP request: delay 0 ... 2 sec
1093 3rd BOOTP request: delay 0 ... 4 sec
1095 BOOTP requests: delay 0 ... 8 sec
1097 - DHCP Advanced Options:
1100 You can fine tune the DHCP functionality by adding
1101 these flags to the CONFIG_BOOTP_MASK define:
1103 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1104 serverip from a DHCP server, it is possible that more
1105 than one DNS serverip is offered to the client.
1106 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1107 serverip will be stored in the additional environment
1108 variable "dnsip2". The first DNS serverip is always
1109 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1110 is added to the CONFIG_BOOTP_MASK.
1112 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1113 to do a dynamic update of a DNS server. To do this, they
1114 need the hostname of the DHCP requester.
1115 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1116 CONFIG_BOOTP_MASK, the content of the "hostname"
1117 environment variable is passed as option 12 to
1121 CONFIG_CDP_DEVICE_ID
1123 The device id used in CDP trigger frames.
1125 CONFIG_CDP_DEVICE_ID_PREFIX
1127 A two character string which is prefixed to the MAC address
1132 A printf format string which contains the ascii name of
1133 the port. Normally is set to "eth%d" which sets
1134 eth0 for the first ethernet, eth1 for the second etc.
1136 CONFIG_CDP_CAPABILITIES
1138 A 32bit integer which indicates the device capabilities;
1139 0x00000010 for a normal host which does not forwards.
1143 An ascii string containing the version of the software.
1147 An ascii string containing the name of the platform.
1151 A 32bit integer sent on the trigger.
1153 CONFIG_CDP_POWER_CONSUMPTION
1155 A 16bit integer containing the power consumption of the
1156 device in .1 of milliwatts.
1158 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1160 A byte containing the id of the VLAN.
1162 - Status LED: CONFIG_STATUS_LED
1164 Several configurations allow to display the current
1165 status using a LED. For instance, the LED will blink
1166 fast while running U-Boot code, stop blinking as
1167 soon as a reply to a BOOTP request was received, and
1168 start blinking slow once the Linux kernel is running
1169 (supported by a status LED driver in the Linux
1170 kernel). Defining CONFIG_STATUS_LED enables this
1173 - CAN Support: CONFIG_CAN_DRIVER
1175 Defining CONFIG_CAN_DRIVER enables CAN driver support
1176 on those systems that support this (optional)
1177 feature, like the TQM8xxL modules.
1179 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1181 These enable I2C serial bus commands. Defining either of
1182 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1183 include the appropriate I2C driver for the selected cpu.
1185 This will allow you to use i2c commands at the u-boot
1186 command line (as long as you set CFG_CMD_I2C in
1187 CONFIG_COMMANDS) and communicate with i2c based realtime
1188 clock chips. See common/cmd_i2c.c for a description of the
1189 command line interface.
1191 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
1193 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1194 bit-banging) driver instead of CPM or similar hardware
1197 There are several other quantities that must also be
1198 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1200 In both cases you will need to define CFG_I2C_SPEED
1201 to be the frequency (in Hz) at which you wish your i2c bus
1202 to run and CFG_I2C_SLAVE to be the address of this node (ie
1203 the cpu's i2c node address).
1205 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1206 sets the cpu up as a master node and so its address should
1207 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1208 p.16-473). So, set CFG_I2C_SLAVE to 0.
1210 That's all that's required for CONFIG_HARD_I2C.
1212 If you use the software i2c interface (CONFIG_SOFT_I2C)
1213 then the following macros need to be defined (examples are
1214 from include/configs/lwmon.h):
1218 (Optional). Any commands necessary to enable the I2C
1219 controller or configure ports.
1221 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1225 (Only for MPC8260 CPU). The I/O port to use (the code
1226 assumes both bits are on the same port). Valid values
1227 are 0..3 for ports A..D.
1231 The code necessary to make the I2C data line active
1232 (driven). If the data line is open collector, this
1235 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1239 The code necessary to make the I2C data line tri-stated
1240 (inactive). If the data line is open collector, this
1243 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1247 Code that returns TRUE if the I2C data line is high,
1250 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1254 If <bit> is TRUE, sets the I2C data line high. If it
1255 is FALSE, it clears it (low).
1257 eg: #define I2C_SDA(bit) \
1258 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1259 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1263 If <bit> is TRUE, sets the I2C clock line high. If it
1264 is FALSE, it clears it (low).
1266 eg: #define I2C_SCL(bit) \
1267 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1268 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1272 This delay is invoked four times per clock cycle so this
1273 controls the rate of data transfer. The data rate thus
1274 is 1 / (I2C_DELAY * 4). Often defined to be something
1277 #define I2C_DELAY udelay(2)
1281 When a board is reset during an i2c bus transfer
1282 chips might think that the current transfer is still
1283 in progress. On some boards it is possible to access
1284 the i2c SCLK line directly, either by using the
1285 processor pin as a GPIO or by having a second pin
1286 connected to the bus. If this option is defined a
1287 custom i2c_init_board() routine in boards/xxx/board.c
1288 is run early in the boot sequence.
1290 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1292 This option enables configuration of bi_iic_fast[] flags
1293 in u-boot bd_info structure based on u-boot environment
1294 variable "i2cfast". (see also i2cfast)
1296 - SPI Support: CONFIG_SPI
1298 Enables SPI driver (so far only tested with
1299 SPI EEPROM, also an instance works with Crystal A/D and
1300 D/As on the SACSng board)
1304 Enables extended (16-bit) SPI EEPROM addressing.
1305 (symmetrical to CONFIG_I2C_X)
1309 Enables a software (bit-bang) SPI driver rather than
1310 using hardware support. This is a general purpose
1311 driver that only requires three general I/O port pins
1312 (two outputs, one input) to function. If this is
1313 defined, the board configuration must define several
1314 SPI configuration items (port pins to use, etc). For
1315 an example, see include/configs/sacsng.h.
1317 - FPGA Support: CONFIG_FPGA_COUNT
1319 Specify the number of FPGA devices to support.
1323 Used to specify the types of FPGA devices. For example,
1324 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1326 CFG_FPGA_PROG_FEEDBACK
1328 Enable printing of hash marks during FPGA configuration.
1332 Enable checks on FPGA configuration interface busy
1333 status by the configuration function. This option
1334 will require a board or device specific function to
1339 If defined, a function that provides delays in the FPGA
1340 configuration driver.
1342 CFG_FPGA_CHECK_CTRLC
1343 Allow Control-C to interrupt FPGA configuration
1345 CFG_FPGA_CHECK_ERROR
1347 Check for configuration errors during FPGA bitfile
1348 loading. For example, abort during Virtex II
1349 configuration if the INIT_B line goes low (which
1350 indicated a CRC error).
1354 Maximum time to wait for the INIT_B line to deassert
1355 after PROB_B has been deasserted during a Virtex II
1356 FPGA configuration sequence. The default time is 500
1361 Maximum time to wait for BUSY to deassert during
1362 Virtex II FPGA configuration. The default is 5 mS.
1364 CFG_FPGA_WAIT_CONFIG
1366 Time to wait after FPGA configuration. The default is
1369 - Configuration Management:
1372 If defined, this string will be added to the U-Boot
1373 version information (U_BOOT_VERSION)
1375 - Vendor Parameter Protection:
1377 U-Boot considers the values of the environment
1378 variables "serial#" (Board Serial Number) and
1379 "ethaddr" (Ethernet Address) to be parameters that
1380 are set once by the board vendor / manufacturer, and
1381 protects these variables from casual modification by
1382 the user. Once set, these variables are read-only,
1383 and write or delete attempts are rejected. You can
1384 change this behviour:
1386 If CONFIG_ENV_OVERWRITE is #defined in your config
1387 file, the write protection for vendor parameters is
1388 completely disabled. Anybody can change or delete
1391 Alternatively, if you #define _both_ CONFIG_ETHADDR
1392 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1393 ethernet address is installed in the environment,
1394 which can be changed exactly ONCE by the user. [The
1395 serial# is unaffected by this, i. e. it remains
1401 Define this variable to enable the reservation of
1402 "protected RAM", i. e. RAM which is not overwritten
1403 by U-Boot. Define CONFIG_PRAM to hold the number of
1404 kB you want to reserve for pRAM. You can overwrite
1405 this default value by defining an environment
1406 variable "pram" to the number of kB you want to
1407 reserve. Note that the board info structure will
1408 still show the full amount of RAM. If pRAM is
1409 reserved, a new environment variable "mem" will
1410 automatically be defined to hold the amount of
1411 remaining RAM in a form that can be passed as boot
1412 argument to Linux, for instance like that:
1414 setenv bootargs ... mem=\${mem}
1417 This way you can tell Linux not to use this memory,
1418 either, which results in a memory region that will
1419 not be affected by reboots.
1421 *WARNING* If your board configuration uses automatic
1422 detection of the RAM size, you must make sure that
1423 this memory test is non-destructive. So far, the
1424 following board configurations are known to be
1427 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1428 HERMES, IP860, RPXlite, LWMON, LANTEC,
1429 PCU_E, FLAGADM, TQM8260
1434 Define this variable to stop the system in case of a
1435 fatal error, so that you have to reset it manually.
1436 This is probably NOT a good idea for an embedded
1437 system where you want to system to reboot
1438 automatically as fast as possible, but it may be
1439 useful during development since you can try to debug
1440 the conditions that lead to the situation.
1442 CONFIG_NET_RETRY_COUNT
1444 This variable defines the number of retries for
1445 network operations like ARP, RARP, TFTP, or BOOTP
1446 before giving up the operation. If not defined, a
1447 default value of 5 is used.
1449 - Command Interpreter:
1452 Enable auto completion of commands using TAB.
1456 Define this variable to enable the "hush" shell (from
1457 Busybox) as command line interpreter, thus enabling
1458 powerful command line syntax like
1459 if...then...else...fi conditionals or `&&' and '||'
1460 constructs ("shell scripts").
1462 If undefined, you get the old, much simpler behaviour
1463 with a somewhat smaller memory footprint.
1468 This defines the secondary prompt string, which is
1469 printed when the command interpreter needs more input
1470 to complete a command. Usually "> ".
1474 In the current implementation, the local variables
1475 space and global environment variables space are
1476 separated. Local variables are those you define by
1477 simply typing `name=value'. To access a local
1478 variable later on, you have write `$name' or
1479 `${name}'; to execute the contents of a variable
1480 directly type `$name' at the command prompt.
1482 Global environment variables are those you use
1483 setenv/printenv to work with. To run a command stored
1484 in such a variable, you need to use the run command,
1485 and you must not use the '$' sign to access them.
1487 To store commands and special characters in a
1488 variable, please use double quotation marks
1489 surrounding the whole text of the variable, instead
1490 of the backslashes before semicolons and special
1493 - Commandline Editing and History:
1494 CONFIG_CMDLINE_EDITING
1496 Enable editiong and History functions for interactive
1497 commandline input operations
1499 - Default Environment:
1500 CONFIG_EXTRA_ENV_SETTINGS
1502 Define this to contain any number of null terminated
1503 strings (variable = value pairs) that will be part of
1504 the default environment compiled into the boot image.
1506 For example, place something like this in your
1507 board's config file:
1509 #define CONFIG_EXTRA_ENV_SETTINGS \
1513 Warning: This method is based on knowledge about the
1514 internal format how the environment is stored by the
1515 U-Boot code. This is NOT an official, exported
1516 interface! Although it is unlikely that this format
1517 will change soon, there is no guarantee either.
1518 You better know what you are doing here.
1520 Note: overly (ab)use of the default environment is
1521 discouraged. Make sure to check other ways to preset
1522 the environment like the autoscript function or the
1525 - DataFlash Support:
1526 CONFIG_HAS_DATAFLASH
1528 Defining this option enables DataFlash features and
1529 allows to read/write in Dataflash via the standard
1532 - SystemACE Support:
1535 Adding this option adds support for Xilinx SystemACE
1536 chips attached via some sort of local bus. The address
1537 of the chip must alsh be defined in the
1538 CFG_SYSTEMACE_BASE macro. For example:
1540 #define CONFIG_SYSTEMACE
1541 #define CFG_SYSTEMACE_BASE 0xf0000000
1543 When SystemACE support is added, the "ace" device type
1544 becomes available to the fat commands, i.e. fatls.
1546 - TFTP Fixed UDP Port:
1549 If this is defined, the environment variable tftpsrcp
1550 is used to supply the TFTP UDP source port value.
1551 If tftpsrcp isn't defined, the normal pseudo-random port
1552 number generator is used.
1554 Also, the environment variable tftpdstp is used to supply
1555 the TFTP UDP destination port value. If tftpdstp isn't
1556 defined, the normal port 69 is used.
1558 The purpose for tftpsrcp is to allow a TFTP server to
1559 blindly start the TFTP transfer using the pre-configured
1560 target IP address and UDP port. This has the effect of
1561 "punching through" the (Windows XP) firewall, allowing
1562 the remainder of the TFTP transfer to proceed normally.
1563 A better solution is to properly configure the firewall,
1564 but sometimes that is not allowed.
1566 - Show boot progress:
1567 CONFIG_SHOW_BOOT_PROGRESS
1569 Defining this option allows to add some board-
1570 specific code (calling a user-provided function
1571 "show_boot_progress(int)") that enables you to show
1572 the system's boot progress on some display (for
1573 example, some LED's) on your board. At the moment,
1574 the following checkpoints are implemented:
1577 1 common/cmd_bootm.c before attempting to boot an image
1578 -1 common/cmd_bootm.c Image header has bad magic number
1579 2 common/cmd_bootm.c Image header has correct magic number
1580 -2 common/cmd_bootm.c Image header has bad checksum
1581 3 common/cmd_bootm.c Image header has correct checksum
1582 -3 common/cmd_bootm.c Image data has bad checksum
1583 4 common/cmd_bootm.c Image data has correct checksum
1584 -4 common/cmd_bootm.c Image is for unsupported architecture
1585 5 common/cmd_bootm.c Architecture check OK
1586 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1587 6 common/cmd_bootm.c Image Type check OK
1588 -6 common/cmd_bootm.c gunzip uncompression error
1589 -7 common/cmd_bootm.c Unimplemented compression type
1590 7 common/cmd_bootm.c Uncompression OK
1591 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1592 8 common/cmd_bootm.c Image Type check OK
1593 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1594 9 common/cmd_bootm.c Start initial ramdisk verification
1595 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1596 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1597 10 common/cmd_bootm.c Ramdisk header is OK
1598 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1599 11 common/cmd_bootm.c Ramdisk data has correct checksum
1600 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1601 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1602 13 common/cmd_bootm.c Start multifile image verification
1603 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1604 15 common/cmd_bootm.c All preparation done, transferring control to OS
1606 -30 lib_ppc/board.c Fatal error, hang the system
1607 -31 post/post.c POST test failed, detected by post_output_backlog()
1608 -32 post/post.c POST test failed, detected by post_run_single()
1610 -1 common/cmd_doc.c Bad usage of "doc" command
1611 -1 common/cmd_doc.c No boot device
1612 -1 common/cmd_doc.c Unknown Chip ID on boot device
1613 -1 common/cmd_doc.c Read Error on boot device
1614 -1 common/cmd_doc.c Image header has bad magic number
1616 -1 common/cmd_ide.c Bad usage of "ide" command
1617 -1 common/cmd_ide.c No boot device
1618 -1 common/cmd_ide.c Unknown boot device
1619 -1 common/cmd_ide.c Unknown partition table
1620 -1 common/cmd_ide.c Invalid partition type
1621 -1 common/cmd_ide.c Read Error on boot device
1622 -1 common/cmd_ide.c Image header has bad magic number
1624 -1 common/cmd_nand.c Bad usage of "nand" command
1625 -1 common/cmd_nand.c No boot device
1626 -1 common/cmd_nand.c Unknown Chip ID on boot device
1627 -1 common/cmd_nand.c Read Error on boot device
1628 -1 common/cmd_nand.c Image header has bad magic number
1630 -1 common/env_common.c Environment has a bad CRC, using default
1636 [so far only for SMDK2400 and TRAB boards]
1638 - Modem support endable:
1639 CONFIG_MODEM_SUPPORT
1641 - RTS/CTS Flow control enable:
1644 - Modem debug support:
1645 CONFIG_MODEM_SUPPORT_DEBUG
1647 Enables debugging stuff (char screen[1024], dbg())
1648 for modem support. Useful only with BDI2000.
1650 - Interrupt support (PPC):
1652 There are common interrupt_init() and timer_interrupt()
1653 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1654 for cpu specific initialization. interrupt_init_cpu()
1655 should set decrementer_count to appropriate value. If
1656 cpu resets decrementer automatically after interrupt
1657 (ppc4xx) it should set decrementer_count to zero.
1658 timer_interrupt() calls timer_interrupt_cpu() for cpu
1659 specific handling. If board has watchdog / status_led
1660 / other_activity_monitor it works automatically from
1661 general timer_interrupt().
1665 In the target system modem support is enabled when a
1666 specific key (key combination) is pressed during
1667 power-on. Otherwise U-Boot will boot normally
1668 (autoboot). The key_pressed() fuction is called from
1669 board_init(). Currently key_pressed() is a dummy
1670 function, returning 1 and thus enabling modem
1673 If there are no modem init strings in the
1674 environment, U-Boot proceed to autoboot; the
1675 previous output (banner, info printfs) will be
1678 See also: doc/README.Modem
1681 Configuration Settings:
1682 -----------------------
1684 - CFG_LONGHELP: Defined when you want long help messages included;
1685 undefine this when you're short of memory.
1687 - CFG_PROMPT: This is what U-Boot prints on the console to
1688 prompt for user input.
1690 - CFG_CBSIZE: Buffer size for input from the Console
1692 - CFG_PBSIZE: Buffer size for Console output
1694 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1696 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1697 the application (usually a Linux kernel) when it is
1700 - CFG_BAUDRATE_TABLE:
1701 List of legal baudrate settings for this board.
1703 - CFG_CONSOLE_INFO_QUIET
1704 Suppress display of console information at boot.
1706 - CFG_CONSOLE_IS_IN_ENV
1707 If the board specific function
1708 extern int overwrite_console (void);
1709 returns 1, the stdin, stderr and stdout are switched to the
1710 serial port, else the settings in the environment are used.
1712 - CFG_CONSOLE_OVERWRITE_ROUTINE
1713 Enable the call to overwrite_console().
1715 - CFG_CONSOLE_ENV_OVERWRITE
1716 Enable overwrite of previous console environment settings.
1718 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1719 Begin and End addresses of the area used by the
1723 Enable an alternate, more extensive memory test.
1725 - CFG_MEMTEST_SCRATCH:
1726 Scratch address used by the alternate memory test
1727 You only need to set this if address zero isn't writeable
1729 - CFG_TFTP_LOADADDR:
1730 Default load address for network file downloads
1732 - CFG_LOADS_BAUD_CHANGE:
1733 Enable temporary baudrate change while serial download
1736 Physical start address of SDRAM. _Must_ be 0 here.
1739 Physical start address of Motherboard I/O (if using a
1743 Physical start address of Flash memory.
1746 Physical start address of boot monitor code (set by
1747 make config files to be same as the text base address
1748 (TEXT_BASE) used when linking) - same as
1749 CFG_FLASH_BASE when booting from flash.
1752 Size of memory reserved for monitor code, used to
1753 determine _at_compile_time_ (!) if the environment is
1754 embedded within the U-Boot image, or in a separate
1758 Size of DRAM reserved for malloc() use.
1761 Normally compressed uImages are limited to an
1762 uncompressed size of 8 MBytes. If this is not enough,
1763 you can define CFG_BOOTM_LEN in your board config file
1764 to adjust this setting to your needs.
1767 Maximum size of memory mapped by the startup code of
1768 the Linux kernel; all data that must be processed by
1769 the Linux kernel (bd_info, boot arguments, eventually
1770 initrd image) must be put below this limit.
1772 - CFG_MAX_FLASH_BANKS:
1773 Max number of Flash memory banks
1775 - CFG_MAX_FLASH_SECT:
1776 Max number of sectors on a Flash chip
1778 - CFG_FLASH_ERASE_TOUT:
1779 Timeout for Flash erase operations (in ms)
1781 - CFG_FLASH_WRITE_TOUT:
1782 Timeout for Flash write operations (in ms)
1784 - CFG_FLASH_LOCK_TOUT
1785 Timeout for Flash set sector lock bit operation (in ms)
1787 - CFG_FLASH_UNLOCK_TOUT
1788 Timeout for Flash clear lock bits operation (in ms)
1790 - CFG_FLASH_PROTECTION
1791 If defined, hardware flash sectors protection is used
1792 instead of U-Boot software protection.
1794 - CFG_DIRECT_FLASH_TFTP:
1796 Enable TFTP transfers directly to flash memory;
1797 without this option such a download has to be
1798 performed in two steps: (1) download to RAM, and (2)
1799 copy from RAM to flash.
1801 The two-step approach is usually more reliable, since
1802 you can check if the download worked before you erase
1803 the flash, but in some situations (when sytem RAM is
1804 too limited to allow for a tempory copy of the
1805 downloaded image) this option may be very useful.
1808 Define if the flash driver uses extra elements in the
1809 common flash structure for storing flash geometry.
1811 - CFG_FLASH_CFI_DRIVER
1812 This option also enables the building of the cfi_flash driver
1813 in the drivers directory
1815 - CFG_FLASH_QUIET_TEST
1816 If this option is defined, the common CFI flash doesn't
1817 print it's warning upon not recognized FLASH banks. This
1818 is useful, if some of the configured banks are only
1819 optionally available.
1821 - CFG_RX_ETH_BUFFER:
1822 Defines the number of ethernet receive buffers. On some
1823 ethernet controllers it is recommended to set this value
1824 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1825 buffers can be full shortly after enabling the interface
1826 on high ethernet traffic.
1827 Defaults to 4 if not defined.
1829 The following definitions that deal with the placement and management
1830 of environment data (variable area); in general, we support the
1831 following configurations:
1833 - CFG_ENV_IS_IN_FLASH:
1835 Define this if the environment is in flash memory.
1837 a) The environment occupies one whole flash sector, which is
1838 "embedded" in the text segment with the U-Boot code. This
1839 happens usually with "bottom boot sector" or "top boot
1840 sector" type flash chips, which have several smaller
1841 sectors at the start or the end. For instance, such a
1842 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1843 such a case you would place the environment in one of the
1844 4 kB sectors - with U-Boot code before and after it. With
1845 "top boot sector" type flash chips, you would put the
1846 environment in one of the last sectors, leaving a gap
1847 between U-Boot and the environment.
1851 Offset of environment data (variable area) to the
1852 beginning of flash memory; for instance, with bottom boot
1853 type flash chips the second sector can be used: the offset
1854 for this sector is given here.
1856 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1860 This is just another way to specify the start address of
1861 the flash sector containing the environment (instead of
1864 - CFG_ENV_SECT_SIZE:
1866 Size of the sector containing the environment.
1869 b) Sometimes flash chips have few, equal sized, BIG sectors.
1870 In such a case you don't want to spend a whole sector for
1875 If you use this in combination with CFG_ENV_IS_IN_FLASH
1876 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1877 of this flash sector for the environment. This saves
1878 memory for the RAM copy of the environment.
1880 It may also save flash memory if you decide to use this
1881 when your environment is "embedded" within U-Boot code,
1882 since then the remainder of the flash sector could be used
1883 for U-Boot code. It should be pointed out that this is
1884 STRONGLY DISCOURAGED from a robustness point of view:
1885 updating the environment in flash makes it always
1886 necessary to erase the WHOLE sector. If something goes
1887 wrong before the contents has been restored from a copy in
1888 RAM, your target system will be dead.
1890 - CFG_ENV_ADDR_REDUND
1893 These settings describe a second storage area used to hold
1894 a redundand copy of the environment data, so that there is
1895 a valid backup copy in case there is a power failure during
1896 a "saveenv" operation.
1898 BE CAREFUL! Any changes to the flash layout, and some changes to the
1899 source code will make it necessary to adapt <board>/u-boot.lds*
1903 - CFG_ENV_IS_IN_NVRAM:
1905 Define this if you have some non-volatile memory device
1906 (NVRAM, battery buffered SRAM) which you want to use for the
1912 These two #defines are used to determin the memory area you
1913 want to use for environment. It is assumed that this memory
1914 can just be read and written to, without any special
1917 BE CAREFUL! The first access to the environment happens quite early
1918 in U-Boot initalization (when we try to get the setting of for the
1919 console baudrate). You *MUST* have mappend your NVRAM area then, or
1922 Please note that even with NVRAM we still use a copy of the
1923 environment in RAM: we could work on NVRAM directly, but we want to
1924 keep settings there always unmodified except somebody uses "saveenv"
1925 to save the current settings.
1928 - CFG_ENV_IS_IN_EEPROM:
1930 Use this if you have an EEPROM or similar serial access
1931 device and a driver for it.
1936 These two #defines specify the offset and size of the
1937 environment area within the total memory of your EEPROM.
1939 - CFG_I2C_EEPROM_ADDR:
1940 If defined, specified the chip address of the EEPROM device.
1941 The default address is zero.
1943 - CFG_EEPROM_PAGE_WRITE_BITS:
1944 If defined, the number of bits used to address bytes in a
1945 single page in the EEPROM device. A 64 byte page, for example
1946 would require six bits.
1948 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1949 If defined, the number of milliseconds to delay between
1950 page writes. The default is zero milliseconds.
1952 - CFG_I2C_EEPROM_ADDR_LEN:
1953 The length in bytes of the EEPROM memory array address. Note
1954 that this is NOT the chip address length!
1956 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
1957 EEPROM chips that implement "address overflow" are ones
1958 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
1959 address and the extra bits end up in the "chip address" bit
1960 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
1963 Note that we consider the length of the address field to
1964 still be one byte because the extra address bits are hidden
1965 in the chip address.
1968 The size in bytes of the EEPROM device.
1971 - CFG_ENV_IS_IN_DATAFLASH:
1973 Define this if you have a DataFlash memory device which you
1974 want to use for the environment.
1980 These three #defines specify the offset and size of the
1981 environment area within the total memory of your DataFlash placed
1982 at the specified address.
1984 - CFG_ENV_IS_IN_NAND:
1986 Define this if you have a NAND device which you want to use
1987 for the environment.
1992 These two #defines specify the offset and size of the environment
1993 area within the first NAND device.
1995 - CFG_ENV_OFFSET_REDUND
1997 This setting describes a second storage area of CFG_ENV_SIZE
1998 size used to hold a redundant copy of the environment data,
1999 so that there is a valid backup copy in case there is a
2000 power failure during a "saveenv" operation.
2002 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2003 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2004 the NAND devices block size.
2006 - CFG_SPI_INIT_OFFSET
2008 Defines offset to the initial SPI buffer area in DPRAM. The
2009 area is used at an early stage (ROM part) if the environment
2010 is configured to reside in the SPI EEPROM: We need a 520 byte
2011 scratch DPRAM area. It is used between the two initialization
2012 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2013 to be a good choice since it makes it far enough from the
2014 start of the data area as well as from the stack pointer.
2016 Please note that the environment is read-only as long as the monitor
2017 has been relocated to RAM and a RAM copy of the environment has been
2018 created; also, when using EEPROM you will have to use getenv_r()
2019 until then to read environment variables.
2021 The environment is protected by a CRC32 checksum. Before the monitor
2022 is relocated into RAM, as a result of a bad CRC you will be working
2023 with the compiled-in default environment - *silently*!!! [This is
2024 necessary, because the first environment variable we need is the
2025 "baudrate" setting for the console - if we have a bad CRC, we don't
2026 have any device yet where we could complain.]
2028 Note: once the monitor has been relocated, then it will complain if
2029 the default environment is used; a new CRC is computed as soon as you
2030 use the "saveenv" command to store a valid environment.
2032 - CFG_FAULT_ECHO_LINK_DOWN:
2033 Echo the inverted Ethernet link state to the fault LED.
2035 Note: If this option is active, then CFG_FAULT_MII_ADDR
2036 also needs to be defined.
2038 - CFG_FAULT_MII_ADDR:
2039 MII address of the PHY to check for the Ethernet link state.
2041 - CFG_64BIT_VSPRINTF:
2042 Makes vsprintf (and all *printf functions) support printing
2043 of 64bit values by using the L quantifier
2045 - CFG_64BIT_STRTOUL:
2046 Adds simple_strtoull that returns a 64bit value
2048 Low Level (hardware related) configuration options:
2049 ---------------------------------------------------
2051 - CFG_CACHELINE_SIZE:
2052 Cache Line Size of the CPU.
2055 Default address of the IMMR after system reset.
2057 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2058 and RPXsuper) to be able to adjust the position of
2059 the IMMR register after a reset.
2061 - Floppy Disk Support:
2062 CFG_FDC_DRIVE_NUMBER
2064 the default drive number (default value 0)
2068 defines the spacing between fdc chipset registers
2073 defines the offset of register from address. It
2074 depends on which part of the data bus is connected to
2075 the fdc chipset. (default value 0)
2077 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2078 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2081 if CFG_FDC_HW_INIT is defined, then the function
2082 fdc_hw_init() is called at the beginning of the FDC
2083 setup. fdc_hw_init() must be provided by the board
2084 source code. It is used to make hardware dependant
2087 - CFG_IMMR: Physical address of the Internal Memory.
2088 DO NOT CHANGE unless you know exactly what you're
2089 doing! (11-4) [MPC8xx/82xx systems only]
2091 - CFG_INIT_RAM_ADDR:
2093 Start address of memory area that can be used for
2094 initial data and stack; please note that this must be
2095 writable memory that is working WITHOUT special
2096 initialization, i. e. you CANNOT use normal RAM which
2097 will become available only after programming the
2098 memory controller and running certain initialization
2101 U-Boot uses the following memory types:
2102 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2103 - MPC824X: data cache
2104 - PPC4xx: data cache
2106 - CFG_GBL_DATA_OFFSET:
2108 Offset of the initial data structure in the memory
2109 area defined by CFG_INIT_RAM_ADDR. Usually
2110 CFG_GBL_DATA_OFFSET is chosen such that the initial
2111 data is located at the end of the available space
2112 (sometimes written as (CFG_INIT_RAM_END -
2113 CFG_INIT_DATA_SIZE), and the initial stack is just
2114 below that area (growing from (CFG_INIT_RAM_ADDR +
2115 CFG_GBL_DATA_OFFSET) downward.
2118 On the MPC824X (or other systems that use the data
2119 cache for initial memory) the address chosen for
2120 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2121 point to an otherwise UNUSED address space between
2122 the top of RAM and the start of the PCI space.
2124 - CFG_SIUMCR: SIU Module Configuration (11-6)
2126 - CFG_SYPCR: System Protection Control (11-9)
2128 - CFG_TBSCR: Time Base Status and Control (11-26)
2130 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2132 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2134 - CFG_SCCR: System Clock and reset Control Register (15-27)
2136 - CFG_OR_TIMING_SDRAM:
2140 periodic timer for refresh
2142 - CFG_DER: Debug Event Register (37-47)
2144 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2145 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2146 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2148 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2150 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2151 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2152 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2153 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2155 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2156 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2157 Machine Mode Register and Memory Periodic Timer
2158 Prescaler definitions (SDRAM timing)
2160 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2161 enable I2C microcode relocation patch (MPC8xx);
2162 define relocation offset in DPRAM [DSP2]
2164 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2165 enable SPI microcode relocation patch (MPC8xx);
2166 define relocation offset in DPRAM [SCC4]
2169 Use OSCM clock mode on MBX8xx board. Be careful,
2170 wrong setting might damage your board. Read
2171 doc/README.MBX before setting this variable!
2173 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2174 Offset of the bootmode word in DPRAM used by post
2175 (Power On Self Tests). This definition overrides
2176 #define'd default value in commproc.h resp.
2179 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2180 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2181 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2182 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2183 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2184 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2185 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2186 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2187 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2189 - CONFIG_ETHER_ON_FEC[12]
2190 Define to enable FEC[12] on a 8xx series processor.
2192 - CONFIG_FEC[12]_PHY
2193 Define to the hardcoded PHY address which corresponds
2194 to the given FEC; i. e.
2195 #define CONFIG_FEC1_PHY 4
2196 means that the PHY with address 4 is connected to FEC1
2198 When set to -1, means to probe for first available.
2200 - CONFIG_FEC[12]_PHY_NORXERR
2201 The PHY does not have a RXERR line (RMII only).
2202 (so program the FEC to ignore it).
2205 Enable RMII mode for all FECs.
2206 Note that this is a global option, we can't
2207 have one FEC in standard MII mode and another in RMII mode.
2209 - CONFIG_CRC32_VERIFY
2210 Add a verify option to the crc32 command.
2213 => crc32 -v <address> <count> <crc32>
2215 Where address/count indicate a memory area
2216 and crc32 is the correct crc32 which the
2220 Add the "loopw" memory command. This only takes effect if
2221 the memory commands are activated globally (CFG_CMD_MEM).
2224 Add the "mdc" and "mwc" memory commands. These are cyclic
2229 This command will print 4 bytes (10,11,12,13) each 500 ms.
2231 => mwc.l 100 12345678 10
2232 This command will write 12345678 to address 100 all 10 ms.
2234 This only takes effect if the memory commands are activated
2235 globally (CFG_CMD_MEM).
2237 - CONFIG_SKIP_LOWLEVEL_INIT
2238 - CONFIG_SKIP_RELOCATE_UBOOT
2240 [ARM only] If these variables are defined, then
2241 certain low level initializations (like setting up
2242 the memory controller) are omitted and/or U-Boot does
2243 not relocate itself into RAM.
2244 Normally these variables MUST NOT be defined. The
2245 only exception is when U-Boot is loaded (to RAM) by
2246 some other boot loader or by a debugger which
2247 performs these intializations itself.
2250 Building the Software:
2251 ======================
2253 Building U-Boot has been tested in native PPC environments (on a
2254 PowerBook G3 running LinuxPPC 2000) and in cross environments
2255 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2258 If you are not using a native PPC environment, it is assumed that you
2259 have the GNU cross compiling tools available in your path and named
2260 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2261 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2262 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2265 CROSS_COMPILE = ppc_4xx-
2268 U-Boot is intended to be simple to build. After installing the
2269 sources you must configure U-Boot for one specific board type. This
2274 where "NAME_config" is the name of one of the existing
2275 configurations; the following names are supported:
2277 ADCIOP_config FPS860L_config omap730p2_config
2278 ADS860_config GEN860T_config pcu_e_config
2280 AR405_config GENIETV_config PIP405_config
2281 at91rm9200dk_config GTH_config QS823_config
2282 CANBT_config hermes_config QS850_config
2283 cmi_mpc5xx_config hymod_config QS860T_config
2284 cogent_common_config IP860_config RPXlite_config
2285 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2286 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2287 CPCI405_config JSE_config rsdproto_config
2288 CPCIISER4_config LANTEC_config Sandpoint8240_config
2289 csb272_config lwmon_config sbc8260_config
2290 CU824_config MBX860T_config sbc8560_33_config
2291 DUET_ADS_config MBX_config sbc8560_66_config
2292 EBONY_config MPC8260ADS_config SM850_config
2293 ELPT860_config MPC8540ADS_config SPD823TS_config
2294 ESTEEM192E_config MPC8540EVAL_config stxgp3_config
2295 ETX094_config MPC8560ADS_config SXNI855T_config
2296 FADS823_config NETVIA_config TQM823L_config
2297 FADS850SAR_config omap1510inn_config TQM850L_config
2298 FADS860T_config omap1610h2_config TQM855L_config
2299 FPS850L_config omap1610inn_config TQM860L_config
2300 omap5912osk_config walnut_config
2301 omap2420h4_config Yukon8220_config
2304 Note: for some board special configuration names may exist; check if
2305 additional information is available from the board vendor; for
2306 instance, the TQM823L systems are available without (standard)
2307 or with LCD support. You can select such additional "features"
2308 when chosing the configuration, i. e.
2311 - will configure for a plain TQM823L, i. e. no LCD support
2313 make TQM823L_LCD_config
2314 - will configure for a TQM823L with U-Boot console on LCD
2319 Finally, type "make all", and you should get some working U-Boot
2320 images ready for download to / installation on your system:
2322 - "u-boot.bin" is a raw binary image
2323 - "u-boot" is an image in ELF binary format
2324 - "u-boot.srec" is in Motorola S-Record format
2327 Please be aware that the Makefiles assume you are using GNU make, so
2328 for instance on NetBSD you might need to use "gmake" instead of
2332 If the system board that you have is not listed, then you will need
2333 to port U-Boot to your hardware platform. To do this, follow these
2336 1. Add a new configuration option for your board to the toplevel
2337 "Makefile" and to the "MAKEALL" script, using the existing
2338 entries as examples. Note that here and at many other places
2339 boards and other names are listed in alphabetical sort order. Please
2341 2. Create a new directory to hold your board specific code. Add any
2342 files you need. In your board directory, you will need at least
2343 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2344 3. Create a new configuration file "include/configs/<board>.h" for
2346 3. If you're porting U-Boot to a new CPU, then also create a new
2347 directory to hold your CPU specific code. Add any files you need.
2348 4. Run "make <board>_config" with your new name.
2349 5. Type "make", and you should get a working "u-boot.srec" file
2350 to be installed on your target system.
2351 6. Debug and solve any problems that might arise.
2352 [Of course, this last step is much harder than it sounds.]
2355 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2356 ==============================================================
2358 If you have modified U-Boot sources (for instance added a new board
2359 or support for new devices, a new CPU, etc.) you are expected to
2360 provide feedback to the other developers. The feedback normally takes
2361 the form of a "patch", i. e. a context diff against a certain (latest
2362 official or latest in CVS) version of U-Boot sources.
2364 But before you submit such a patch, please verify that your modifi-
2365 cation did not break existing code. At least make sure that *ALL* of
2366 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2367 just run the "MAKEALL" script, which will configure and build U-Boot
2368 for ALL supported system. Be warned, this will take a while. You can
2369 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2370 environment variable to the script, i. e. to use the cross tools from
2371 MontaVista's Hard Hat Linux you can type
2373 CROSS_COMPILE=ppc_8xx- MAKEALL
2375 or to build on a native PowerPC system you can type
2377 CROSS_COMPILE=' ' MAKEALL
2379 See also "U-Boot Porting Guide" below.
2382 Monitor Commands - Overview:
2383 ============================
2385 go - start application at address 'addr'
2386 run - run commands in an environment variable
2387 bootm - boot application image from memory
2388 bootp - boot image via network using BootP/TFTP protocol
2389 tftpboot- boot image via network using TFTP protocol
2390 and env variables "ipaddr" and "serverip"
2391 (and eventually "gatewayip")
2392 rarpboot- boot image via network using RARP/TFTP protocol
2393 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2394 loads - load S-Record file over serial line
2395 loadb - load binary file over serial line (kermit mode)
2397 mm - memory modify (auto-incrementing)
2398 nm - memory modify (constant address)
2399 mw - memory write (fill)
2401 cmp - memory compare
2402 crc32 - checksum calculation
2403 imd - i2c memory display
2404 imm - i2c memory modify (auto-incrementing)
2405 inm - i2c memory modify (constant address)
2406 imw - i2c memory write (fill)
2407 icrc32 - i2c checksum calculation
2408 iprobe - probe to discover valid I2C chip addresses
2409 iloop - infinite loop on address range
2410 isdram - print SDRAM configuration information
2411 sspi - SPI utility commands
2412 base - print or set address offset
2413 printenv- print environment variables
2414 setenv - set environment variables
2415 saveenv - save environment variables to persistent storage
2416 protect - enable or disable FLASH write protection
2417 erase - erase FLASH memory
2418 flinfo - print FLASH memory information
2419 bdinfo - print Board Info structure
2420 iminfo - print header information for application image
2421 coninfo - print console devices and informations
2422 ide - IDE sub-system
2423 loop - infinite loop on address range
2424 loopw - infinite write loop on address range
2425 mtest - simple RAM test
2426 icache - enable or disable instruction cache
2427 dcache - enable or disable data cache
2428 reset - Perform RESET of the CPU
2429 echo - echo args to console
2430 version - print monitor version
2431 help - print online help
2432 ? - alias for 'help'
2435 Monitor Commands - Detailed Description:
2436 ========================================
2440 For now: just type "help <command>".
2443 Environment Variables:
2444 ======================
2446 U-Boot supports user configuration using Environment Variables which
2447 can be made persistent by saving to Flash memory.
2449 Environment Variables are set using "setenv", printed using
2450 "printenv", and saved to Flash using "saveenv". Using "setenv"
2451 without a value can be used to delete a variable from the
2452 environment. As long as you don't save the environment you are
2453 working with an in-memory copy. In case the Flash area containing the
2454 environment is erased by accident, a default environment is provided.
2456 Some configuration options can be set using Environment Variables:
2458 baudrate - see CONFIG_BAUDRATE
2460 bootdelay - see CONFIG_BOOTDELAY
2462 bootcmd - see CONFIG_BOOTCOMMAND
2464 bootargs - Boot arguments when booting an RTOS image
2466 bootfile - Name of the image to load with TFTP
2468 autoload - if set to "no" (any string beginning with 'n'),
2469 "bootp" will just load perform a lookup of the
2470 configuration from the BOOTP server, but not try to
2471 load any image using TFTP
2473 autostart - if set to "yes", an image loaded using the "bootp",
2474 "rarpboot", "tftpboot" or "diskboot" commands will
2475 be automatically started (by internally calling
2478 If set to "no", a standalone image passed to the
2479 "bootm" command will be copied to the load address
2480 (and eventually uncompressed), but NOT be started.
2481 This can be used to load and uncompress arbitrary
2484 i2cfast - (PPC405GP|PPC405EP only)
2485 if set to 'y' configures Linux I2C driver for fast
2486 mode (400kHZ). This environment variable is used in
2487 initialization code. So, for changes to be effective
2488 it must be saved and board must be reset.
2490 initrd_high - restrict positioning of initrd images:
2491 If this variable is not set, initrd images will be
2492 copied to the highest possible address in RAM; this
2493 is usually what you want since it allows for
2494 maximum initrd size. If for some reason you want to
2495 make sure that the initrd image is loaded below the
2496 CFG_BOOTMAPSZ limit, you can set this environment
2497 variable to a value of "no" or "off" or "0".
2498 Alternatively, you can set it to a maximum upper
2499 address to use (U-Boot will still check that it
2500 does not overwrite the U-Boot stack and data).
2502 For instance, when you have a system with 16 MB
2503 RAM, and want to reserve 4 MB from use by Linux,
2504 you can do this by adding "mem=12M" to the value of
2505 the "bootargs" variable. However, now you must make
2506 sure that the initrd image is placed in the first
2507 12 MB as well - this can be done with
2509 setenv initrd_high 00c00000
2511 If you set initrd_high to 0xFFFFFFFF, this is an
2512 indication to U-Boot that all addresses are legal
2513 for the Linux kernel, including addresses in flash
2514 memory. In this case U-Boot will NOT COPY the
2515 ramdisk at all. This may be useful to reduce the
2516 boot time on your system, but requires that this
2517 feature is supported by your Linux kernel.
2519 ipaddr - IP address; needed for tftpboot command
2521 loadaddr - Default load address for commands like "bootp",
2522 "rarpboot", "tftpboot", "loadb" or "diskboot"
2524 loads_echo - see CONFIG_LOADS_ECHO
2526 serverip - TFTP server IP address; needed for tftpboot command
2528 bootretry - see CONFIG_BOOT_RETRY_TIME
2530 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2532 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2534 ethprime - When CONFIG_NET_MULTI is enabled controls which
2535 interface is used first.
2537 ethact - When CONFIG_NET_MULTI is enabled controls which
2538 interface is currently active. For example you
2539 can do the following
2541 => setenv ethact FEC ETHERNET
2542 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2543 => setenv ethact SCC ETHERNET
2544 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2546 netretry - When set to "no" each network operation will
2547 either succeed or fail without retrying.
2548 When set to "once" the network operation will
2549 fail when all the available network interfaces
2550 are tried once without success.
2551 Useful on scripts which control the retry operation
2554 tftpsrcport - If this is set, the value is used for TFTP's
2557 tftpdstport - If this is set, the value is used for TFTP's UDP
2558 destination port instead of the Well Know Port 69.
2560 vlan - When set to a value < 4095 the traffic over
2561 ethernet is encapsulated/received over 802.1q
2564 The following environment variables may be used and automatically
2565 updated by the network boot commands ("bootp" and "rarpboot"),
2566 depending the information provided by your boot server:
2568 bootfile - see above
2569 dnsip - IP address of your Domain Name Server
2570 dnsip2 - IP address of your secondary Domain Name Server
2571 gatewayip - IP address of the Gateway (Router) to use
2572 hostname - Target hostname
2574 netmask - Subnet Mask
2575 rootpath - Pathname of the root filesystem on the NFS server
2576 serverip - see above
2579 There are two special Environment Variables:
2581 serial# - contains hardware identification information such
2582 as type string and/or serial number
2583 ethaddr - Ethernet address
2585 These variables can be set only once (usually during manufacturing of
2586 the board). U-Boot refuses to delete or overwrite these variables
2587 once they have been set once.
2590 Further special Environment Variables:
2592 ver - Contains the U-Boot version string as printed
2593 with the "version" command. This variable is
2594 readonly (see CONFIG_VERSION_VARIABLE).
2597 Please note that changes to some configuration parameters may take
2598 only effect after the next boot (yes, that's just like Windoze :-).
2601 Command Line Parsing:
2602 =====================
2604 There are two different command line parsers available with U-Boot:
2605 the old "simple" one, and the much more powerful "hush" shell:
2607 Old, simple command line parser:
2608 --------------------------------
2610 - supports environment variables (through setenv / saveenv commands)
2611 - several commands on one line, separated by ';'
2612 - variable substitution using "... ${name} ..." syntax
2613 - special characters ('$', ';') can be escaped by prefixing with '\',
2615 setenv bootcmd bootm \${address}
2616 - You can also escape text by enclosing in single apostrophes, for example:
2617 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2622 - similar to Bourne shell, with control structures like
2623 if...then...else...fi, for...do...done; while...do...done,
2624 until...do...done, ...
2625 - supports environment ("global") variables (through setenv / saveenv
2626 commands) and local shell variables (through standard shell syntax
2627 "name=value"); only environment variables can be used with "run"
2633 (1) If a command line (or an environment variable executed by a "run"
2634 command) contains several commands separated by semicolon, and
2635 one of these commands fails, then the remaining commands will be
2638 (2) If you execute several variables with one call to run (i. e.
2639 calling run with a list af variables as arguments), any failing
2640 command will cause "run" to terminate, i. e. the remaining
2641 variables are not executed.
2643 Note for Redundant Ethernet Interfaces:
2644 =======================================
2646 Some boards come with redundant ethernet interfaces; U-Boot supports
2647 such configurations and is capable of automatic selection of a
2648 "working" interface when needed. MAC assignment works as follows:
2650 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2651 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2652 "eth1addr" (=>eth1), "eth2addr", ...
2654 If the network interface stores some valid MAC address (for instance
2655 in SROM), this is used as default address if there is NO correspon-
2656 ding setting in the environment; if the corresponding environment
2657 variable is set, this overrides the settings in the card; that means:
2659 o If the SROM has a valid MAC address, and there is no address in the
2660 environment, the SROM's address is used.
2662 o If there is no valid address in the SROM, and a definition in the
2663 environment exists, then the value from the environment variable is
2666 o If both the SROM and the environment contain a MAC address, and
2667 both addresses are the same, this MAC address is used.
2669 o If both the SROM and the environment contain a MAC address, and the
2670 addresses differ, the value from the environment is used and a
2673 o If neither SROM nor the environment contain a MAC address, an error
2680 The "boot" commands of this monitor operate on "image" files which
2681 can be basicly anything, preceeded by a special header; see the
2682 definitions in include/image.h for details; basicly, the header
2683 defines the following image properties:
2685 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2686 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2687 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2688 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2689 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2690 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2691 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC).
2692 * Compression Type (uncompressed, gzip, bzip2)
2698 The header is marked by a special Magic Number, and both the header
2699 and the data portions of the image are secured against corruption by
2706 Although U-Boot should support any OS or standalone application
2707 easily, the main focus has always been on Linux during the design of
2710 U-Boot includes many features that so far have been part of some
2711 special "boot loader" code within the Linux kernel. Also, any
2712 "initrd" images to be used are no longer part of one big Linux image;
2713 instead, kernel and "initrd" are separate images. This implementation
2714 serves several purposes:
2716 - the same features can be used for other OS or standalone
2717 applications (for instance: using compressed images to reduce the
2718 Flash memory footprint)
2720 - it becomes much easier to port new Linux kernel versions because
2721 lots of low-level, hardware dependent stuff are done by U-Boot
2723 - the same Linux kernel image can now be used with different "initrd"
2724 images; of course this also means that different kernel images can
2725 be run with the same "initrd". This makes testing easier (you don't
2726 have to build a new "zImage.initrd" Linux image when you just
2727 change a file in your "initrd"). Also, a field-upgrade of the
2728 software is easier now.
2734 Porting Linux to U-Boot based systems:
2735 ---------------------------------------
2737 U-Boot cannot save you from doing all the necessary modifications to
2738 configure the Linux device drivers for use with your target hardware
2739 (no, we don't intend to provide a full virtual machine interface to
2742 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2744 Just make sure your machine specific header file (for instance
2745 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2746 Information structure as we define in include/u-boot.h, and make
2747 sure that your definition of IMAP_ADDR uses the same value as your
2748 U-Boot configuration in CFG_IMMR.
2751 Configuring the Linux kernel:
2752 -----------------------------
2754 No specific requirements for U-Boot. Make sure you have some root
2755 device (initial ramdisk, NFS) for your target system.
2758 Building a Linux Image:
2759 -----------------------
2761 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2762 not used. If you use recent kernel source, a new build target
2763 "uImage" will exist which automatically builds an image usable by
2764 U-Boot. Most older kernels also have support for a "pImage" target,
2765 which was introduced for our predecessor project PPCBoot and uses a
2766 100% compatible format.
2775 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2776 encapsulate a compressed Linux kernel image with header information,
2777 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2779 * build a standard "vmlinux" kernel image (in ELF binary format):
2781 * convert the kernel into a raw binary image:
2783 ${CROSS_COMPILE}-objcopy -O binary \
2784 -R .note -R .comment \
2785 -S vmlinux linux.bin
2787 * compress the binary image:
2791 * package compressed binary image for U-Boot:
2793 mkimage -A ppc -O linux -T kernel -C gzip \
2794 -a 0 -e 0 -n "Linux Kernel Image" \
2795 -d linux.bin.gz uImage
2798 The "mkimage" tool can also be used to create ramdisk images for use
2799 with U-Boot, either separated from the Linux kernel image, or
2800 combined into one file. "mkimage" encapsulates the images with a 64
2801 byte header containing information about target architecture,
2802 operating system, image type, compression method, entry points, time
2803 stamp, CRC32 checksums, etc.
2805 "mkimage" can be called in two ways: to verify existing images and
2806 print the header information, or to build new images.
2808 In the first form (with "-l" option) mkimage lists the information
2809 contained in the header of an existing U-Boot image; this includes
2810 checksum verification:
2812 tools/mkimage -l image
2813 -l ==> list image header information
2815 The second form (with "-d" option) is used to build a U-Boot image
2816 from a "data file" which is used as image payload:
2818 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2819 -n name -d data_file image
2820 -A ==> set architecture to 'arch'
2821 -O ==> set operating system to 'os'
2822 -T ==> set image type to 'type'
2823 -C ==> set compression type 'comp'
2824 -a ==> set load address to 'addr' (hex)
2825 -e ==> set entry point to 'ep' (hex)
2826 -n ==> set image name to 'name'
2827 -d ==> use image data from 'datafile'
2829 Right now, all Linux kernels for PowerPC systems use the same load
2830 address (0x00000000), but the entry point address depends on the
2833 - 2.2.x kernels have the entry point at 0x0000000C,
2834 - 2.3.x and later kernels have the entry point at 0x00000000.
2836 So a typical call to build a U-Boot image would read:
2838 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2839 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2840 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2841 > examples/uImage.TQM850L
2842 Image Name: 2.4.4 kernel for TQM850L
2843 Created: Wed Jul 19 02:34:59 2000
2844 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2845 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2846 Load Address: 0x00000000
2847 Entry Point: 0x00000000
2849 To verify the contents of the image (or check for corruption):
2851 -> tools/mkimage -l examples/uImage.TQM850L
2852 Image Name: 2.4.4 kernel for TQM850L
2853 Created: Wed Jul 19 02:34:59 2000
2854 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2855 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2856 Load Address: 0x00000000
2857 Entry Point: 0x00000000
2859 NOTE: for embedded systems where boot time is critical you can trade
2860 speed for memory and install an UNCOMPRESSED image instead: this
2861 needs more space in Flash, but boots much faster since it does not
2862 need to be uncompressed:
2864 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2865 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2866 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2867 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2868 > examples/uImage.TQM850L-uncompressed
2869 Image Name: 2.4.4 kernel for TQM850L
2870 Created: Wed Jul 19 02:34:59 2000
2871 Image Type: PowerPC Linux Kernel Image (uncompressed)
2872 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2873 Load Address: 0x00000000
2874 Entry Point: 0x00000000
2877 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2878 when your kernel is intended to use an initial ramdisk:
2880 -> tools/mkimage -n 'Simple Ramdisk Image' \
2881 > -A ppc -O linux -T ramdisk -C gzip \
2882 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2883 Image Name: Simple Ramdisk Image
2884 Created: Wed Jan 12 14:01:50 2000
2885 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2886 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2887 Load Address: 0x00000000
2888 Entry Point: 0x00000000
2891 Installing a Linux Image:
2892 -------------------------
2894 To downloading a U-Boot image over the serial (console) interface,
2895 you must convert the image to S-Record format:
2897 objcopy -I binary -O srec examples/image examples/image.srec
2899 The 'objcopy' does not understand the information in the U-Boot
2900 image header, so the resulting S-Record file will be relative to
2901 address 0x00000000. To load it to a given address, you need to
2902 specify the target address as 'offset' parameter with the 'loads'
2905 Example: install the image to address 0x40100000 (which on the
2906 TQM8xxL is in the first Flash bank):
2908 => erase 40100000 401FFFFF
2914 ## Ready for S-Record download ...
2915 ~>examples/image.srec
2916 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2918 15989 15990 15991 15992
2919 [file transfer complete]
2921 ## Start Addr = 0x00000000
2924 You can check the success of the download using the 'iminfo' command;
2925 this includes a checksum verification so you can be sure no data
2926 corruption happened:
2930 ## Checking Image at 40100000 ...
2931 Image Name: 2.2.13 for initrd on TQM850L
2932 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2933 Data Size: 335725 Bytes = 327 kB = 0 MB
2934 Load Address: 00000000
2935 Entry Point: 0000000c
2936 Verifying Checksum ... OK
2942 The "bootm" command is used to boot an application that is stored in
2943 memory (RAM or Flash). In case of a Linux kernel image, the contents
2944 of the "bootargs" environment variable is passed to the kernel as
2945 parameters. You can check and modify this variable using the
2946 "printenv" and "setenv" commands:
2949 => printenv bootargs
2950 bootargs=root=/dev/ram
2952 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2954 => printenv bootargs
2955 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2958 ## Booting Linux kernel at 40020000 ...
2959 Image Name: 2.2.13 for NFS on TQM850L
2960 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2961 Data Size: 381681 Bytes = 372 kB = 0 MB
2962 Load Address: 00000000
2963 Entry Point: 0000000c
2964 Verifying Checksum ... OK
2965 Uncompressing Kernel Image ... OK
2966 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
2967 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2968 time_init: decrementer frequency = 187500000/60
2969 Calibrating delay loop... 49.77 BogoMIPS
2970 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2973 If you want to boot a Linux kernel with initial ram disk, you pass
2974 the memory addresses of both the kernel and the initrd image (PPBCOOT
2975 format!) to the "bootm" command:
2977 => imi 40100000 40200000
2979 ## Checking Image at 40100000 ...
2980 Image Name: 2.2.13 for initrd on TQM850L
2981 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2982 Data Size: 335725 Bytes = 327 kB = 0 MB
2983 Load Address: 00000000
2984 Entry Point: 0000000c
2985 Verifying Checksum ... OK
2987 ## Checking Image at 40200000 ...
2988 Image Name: Simple Ramdisk Image
2989 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2990 Data Size: 566530 Bytes = 553 kB = 0 MB
2991 Load Address: 00000000
2992 Entry Point: 00000000
2993 Verifying Checksum ... OK
2995 => bootm 40100000 40200000
2996 ## Booting Linux kernel at 40100000 ...
2997 Image Name: 2.2.13 for initrd on TQM850L
2998 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2999 Data Size: 335725 Bytes = 327 kB = 0 MB
3000 Load Address: 00000000
3001 Entry Point: 0000000c
3002 Verifying Checksum ... OK
3003 Uncompressing Kernel Image ... OK
3004 ## Loading RAMDisk Image at 40200000 ...
3005 Image Name: Simple Ramdisk Image
3006 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3007 Data Size: 566530 Bytes = 553 kB = 0 MB
3008 Load Address: 00000000
3009 Entry Point: 00000000
3010 Verifying Checksum ... OK
3011 Loading Ramdisk ... OK
3012 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
3013 Boot arguments: root=/dev/ram
3014 time_init: decrementer frequency = 187500000/60
3015 Calibrating delay loop... 49.77 BogoMIPS
3017 RAMDISK: Compressed image found at block 0
3018 VFS: Mounted root (ext2 filesystem).
3022 More About U-Boot Image Types:
3023 ------------------------------
3025 U-Boot supports the following image types:
3027 "Standalone Programs" are directly runnable in the environment
3028 provided by U-Boot; it is expected that (if they behave
3029 well) you can continue to work in U-Boot after return from
3030 the Standalone Program.
3031 "OS Kernel Images" are usually images of some Embedded OS which
3032 will take over control completely. Usually these programs
3033 will install their own set of exception handlers, device
3034 drivers, set up the MMU, etc. - this means, that you cannot
3035 expect to re-enter U-Boot except by resetting the CPU.
3036 "RAMDisk Images" are more or less just data blocks, and their
3037 parameters (address, size) are passed to an OS kernel that is
3039 "Multi-File Images" contain several images, typically an OS
3040 (Linux) kernel image and one or more data images like
3041 RAMDisks. This construct is useful for instance when you want
3042 to boot over the network using BOOTP etc., where the boot
3043 server provides just a single image file, but you want to get
3044 for instance an OS kernel and a RAMDisk image.
3046 "Multi-File Images" start with a list of image sizes, each
3047 image size (in bytes) specified by an "uint32_t" in network
3048 byte order. This list is terminated by an "(uint32_t)0".
3049 Immediately after the terminating 0 follow the images, one by
3050 one, all aligned on "uint32_t" boundaries (size rounded up to
3051 a multiple of 4 bytes).
3053 "Firmware Images" are binary images containing firmware (like
3054 U-Boot or FPGA images) which usually will be programmed to
3057 "Script files" are command sequences that will be executed by
3058 U-Boot's command interpreter; this feature is especially
3059 useful when you configure U-Boot to use a real shell (hush)
3060 as command interpreter.
3066 One of the features of U-Boot is that you can dynamically load and
3067 run "standalone" applications, which can use some resources of
3068 U-Boot like console I/O functions or interrupt services.
3070 Two simple examples are included with the sources:
3075 'examples/hello_world.c' contains a small "Hello World" Demo
3076 application; it is automatically compiled when you build U-Boot.
3077 It's configured to run at address 0x00040004, so you can play with it
3081 ## Ready for S-Record download ...
3082 ~>examples/hello_world.srec
3083 1 2 3 4 5 6 7 8 9 10 11 ...
3084 [file transfer complete]
3086 ## Start Addr = 0x00040004
3088 => go 40004 Hello World! This is a test.
3089 ## Starting application at 0x00040004 ...
3100 Hit any key to exit ...
3102 ## Application terminated, rc = 0x0
3104 Another example, which demonstrates how to register a CPM interrupt
3105 handler with the U-Boot code, can be found in 'examples/timer.c'.
3106 Here, a CPM timer is set up to generate an interrupt every second.
3107 The interrupt service routine is trivial, just printing a '.'
3108 character, but this is just a demo program. The application can be
3109 controlled by the following keys:
3111 ? - print current values og the CPM Timer registers
3112 b - enable interrupts and start timer
3113 e - stop timer and disable interrupts
3114 q - quit application
3117 ## Ready for S-Record download ...
3118 ~>examples/timer.srec
3119 1 2 3 4 5 6 7 8 9 10 11 ...
3120 [file transfer complete]
3122 ## Start Addr = 0x00040004
3125 ## Starting application at 0x00040004 ...
3128 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3131 [q, b, e, ?] Set interval 1000000 us
3134 [q, b, e, ?] ........
3135 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3138 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3141 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3144 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3146 [q, b, e, ?] ...Stopping timer
3148 [q, b, e, ?] ## Application terminated, rc = 0x0
3154 Over time, many people have reported problems when trying to use the
3155 "minicom" terminal emulation program for serial download. I (wd)
3156 consider minicom to be broken, and recommend not to use it. Under
3157 Unix, I recommend to use C-Kermit for general purpose use (and
3158 especially for kermit binary protocol download ("loadb" command), and
3159 use "cu" for S-Record download ("loads" command).
3161 Nevertheless, if you absolutely want to use it try adding this
3162 configuration to your "File transfer protocols" section:
3164 Name Program Name U/D FullScr IO-Red. Multi
3165 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3166 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3172 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3173 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3175 Building requires a cross environment; it is known to work on
3176 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3177 need gmake since the Makefiles are not compatible with BSD make).
3178 Note that the cross-powerpc package does not install include files;
3179 attempting to build U-Boot will fail because <machine/ansi.h> is
3180 missing. This file has to be installed and patched manually:
3182 # cd /usr/pkg/cross/powerpc-netbsd/include
3184 # ln -s powerpc machine
3185 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3186 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3188 Native builds *don't* work due to incompatibilities between native
3189 and U-Boot include files.
3191 Booting assumes that (the first part of) the image booted is a
3192 stage-2 loader which in turn loads and then invokes the kernel
3193 proper. Loader sources will eventually appear in the NetBSD source
3194 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3195 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3198 Implementation Internals:
3199 =========================
3201 The following is not intended to be a complete description of every
3202 implementation detail. However, it should help to understand the
3203 inner workings of U-Boot and make it easier to port it to custom
3207 Initial Stack, Global Data:
3208 ---------------------------
3210 The implementation of U-Boot is complicated by the fact that U-Boot
3211 starts running out of ROM (flash memory), usually without access to
3212 system RAM (because the memory controller is not initialized yet).
3213 This means that we don't have writable Data or BSS segments, and BSS
3214 is not initialized as zero. To be able to get a C environment working
3215 at all, we have to allocate at least a minimal stack. Implementation
3216 options for this are defined and restricted by the CPU used: Some CPU
3217 models provide on-chip memory (like the IMMR area on MPC8xx and
3218 MPC826x processors), on others (parts of) the data cache can be
3219 locked as (mis-) used as memory, etc.
3221 Chris Hallinan posted a good summary of these issues to the
3222 u-boot-users mailing list:
3224 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3225 From: "Chris Hallinan" <clh@net1plus.com>
3226 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3229 Correct me if I'm wrong, folks, but the way I understand it
3230 is this: Using DCACHE as initial RAM for Stack, etc, does not
3231 require any physical RAM backing up the cache. The cleverness
3232 is that the cache is being used as a temporary supply of
3233 necessary storage before the SDRAM controller is setup. It's
3234 beyond the scope of this list to expain the details, but you
3235 can see how this works by studying the cache architecture and
3236 operation in the architecture and processor-specific manuals.
3238 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3239 is another option for the system designer to use as an
3240 initial stack/ram area prior to SDRAM being available. Either
3241 option should work for you. Using CS 4 should be fine if your
3242 board designers haven't used it for something that would
3243 cause you grief during the initial boot! It is frequently not
3246 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3247 with your processor/board/system design. The default value
3248 you will find in any recent u-boot distribution in
3249 walnut.h should work for you. I'd set it to a value larger
3250 than your SDRAM module. If you have a 64MB SDRAM module, set
3251 it above 400_0000. Just make sure your board has no resources
3252 that are supposed to respond to that address! That code in
3253 start.S has been around a while and should work as is when
3254 you get the config right.
3259 It is essential to remember this, since it has some impact on the C
3260 code for the initialization procedures:
3262 * Initialized global data (data segment) is read-only. Do not attempt
3265 * Do not use any unitialized global data (or implicitely initialized
3266 as zero data - BSS segment) at all - this is undefined, initiali-
3267 zation is performed later (when relocating to RAM).
3269 * Stack space is very limited. Avoid big data buffers or things like
3272 Having only the stack as writable memory limits means we cannot use
3273 normal global data to share information beween the code. But it
3274 turned out that the implementation of U-Boot can be greatly
3275 simplified by making a global data structure (gd_t) available to all
3276 functions. We could pass a pointer to this data as argument to _all_
3277 functions, but this would bloat the code. Instead we use a feature of
3278 the GCC compiler (Global Register Variables) to share the data: we
3279 place a pointer (gd) to the global data into a register which we
3280 reserve for this purpose.
3282 When choosing a register for such a purpose we are restricted by the
3283 relevant (E)ABI specifications for the current architecture, and by
3284 GCC's implementation.
3286 For PowerPC, the following registers have specific use:
3289 R3-R4: parameter passing and return values
3290 R5-R10: parameter passing
3291 R13: small data area pointer
3295 (U-Boot also uses R14 as internal GOT pointer.)
3297 ==> U-Boot will use R29 to hold a pointer to the global data
3299 Note: on PPC, we could use a static initializer (since the
3300 address of the global data structure is known at compile time),
3301 but it turned out that reserving a register results in somewhat
3302 smaller code - although the code savings are not that big (on
3303 average for all boards 752 bytes for the whole U-Boot image,
3304 624 text + 127 data).
3306 On ARM, the following registers are used:
3308 R0: function argument word/integer result
3309 R1-R3: function argument word
3311 R10: stack limit (used only if stack checking if enabled)
3312 R11: argument (frame) pointer
3313 R12: temporary workspace
3316 R15: program counter
3318 ==> U-Boot will use R8 to hold a pointer to the global data
3320 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3321 or current versions of GCC may "optimize" the code too much.
3326 U-Boot runs in system state and uses physical addresses, i.e. the
3327 MMU is not used either for address mapping nor for memory protection.
3329 The available memory is mapped to fixed addresses using the memory
3330 controller. In this process, a contiguous block is formed for each
3331 memory type (Flash, SDRAM, SRAM), even when it consists of several
3332 physical memory banks.
3334 U-Boot is installed in the first 128 kB of the first Flash bank (on
3335 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3336 booting and sizing and initializing DRAM, the code relocates itself
3337 to the upper end of DRAM. Immediately below the U-Boot code some
3338 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3339 configuration setting]. Below that, a structure with global Board
3340 Info data is placed, followed by the stack (growing downward).
3342 Additionally, some exception handler code is copied to the low 8 kB
3343 of DRAM (0x00000000 ... 0x00001FFF).
3345 So a typical memory configuration with 16 MB of DRAM could look like
3348 0x0000 0000 Exception Vector code
3351 0x0000 2000 Free for Application Use
3357 0x00FB FF20 Monitor Stack (Growing downward)
3358 0x00FB FFAC Board Info Data and permanent copy of global data
3359 0x00FC 0000 Malloc Arena
3362 0x00FE 0000 RAM Copy of Monitor Code
3363 ... eventually: LCD or video framebuffer
3364 ... eventually: pRAM (Protected RAM - unchanged by reset)
3365 0x00FF FFFF [End of RAM]
3368 System Initialization:
3369 ----------------------
3371 In the reset configuration, U-Boot starts at the reset entry point
3372 (on most PowerPC systens at address 0x00000100). Because of the reset
3373 configuration for CS0# this is a mirror of the onboard Flash memory.
3374 To be able to re-map memory U-Boot then jumps to its link address.
3375 To be able to implement the initialization code in C, a (small!)
3376 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3377 which provide such a feature like MPC8xx or MPC8260), or in a locked
3378 part of the data cache. After that, U-Boot initializes the CPU core,
3379 the caches and the SIU.
3381 Next, all (potentially) available memory banks are mapped using a
3382 preliminary mapping. For example, we put them on 512 MB boundaries
3383 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3384 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3385 programmed for SDRAM access. Using the temporary configuration, a
3386 simple memory test is run that determines the size of the SDRAM
3389 When there is more than one SDRAM bank, and the banks are of
3390 different size, the largest is mapped first. For equal size, the first
3391 bank (CS2#) is mapped first. The first mapping is always for address
3392 0x00000000, with any additional banks following immediately to create
3393 contiguous memory starting from 0.
3395 Then, the monitor installs itself at the upper end of the SDRAM area
3396 and allocates memory for use by malloc() and for the global Board
3397 Info data; also, the exception vector code is copied to the low RAM
3398 pages, and the final stack is set up.
3400 Only after this relocation will you have a "normal" C environment;
3401 until that you are restricted in several ways, mostly because you are
3402 running from ROM, and because the code will have to be relocated to a
3406 U-Boot Porting Guide:
3407 ----------------------
3409 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3413 int main (int argc, char *argv[])
3415 sighandler_t no_more_time;
3417 signal (SIGALRM, no_more_time);
3418 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3420 if (available_money > available_manpower) {
3421 pay consultant to port U-Boot;
3425 Download latest U-Boot source;
3427 Subscribe to u-boot-users mailing list;
3430 email ("Hi, I am new to U-Boot, how do I get started?");
3434 Read the README file in the top level directory;
3435 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3436 Read the source, Luke;
3439 if (available_money > toLocalCurrency ($2500)) {
3442 Add a lot of aggravation and time;
3445 Create your own board support subdirectory;
3447 Create your own board config file;
3451 Add / modify source code;
3455 email ("Hi, I am having problems...");
3457 Send patch file to Wolfgang;
3462 void no_more_time (int sig)
3471 All contributions to U-Boot should conform to the Linux kernel
3472 coding style; see the file "Documentation/CodingStyle" and the script
3473 "scripts/Lindent" in your Linux kernel source directory. In sources
3474 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3475 spaces before parameters to function calls) is actually used.
3477 Source files originating from a different project (for example the
3478 MTD subsystem) are generally exempt from these guidelines and are not
3479 reformated to ease subsequent migration to newer versions of those
3482 Please note that U-Boot is implemented in C (and to some small parts in
3483 Assembler); no C++ is used, so please do not use C++ style comments (//)
3486 Please also stick to the following formatting rules:
3487 - remove any trailing white space
3488 - use TAB characters for indentation, not spaces
3489 - make sure NOT to use DOS '\r\n' line feeds
3490 - do not add more than 2 empty lines to source files
3491 - do not add trailing empty lines to source files
3493 Submissions which do not conform to the standards may be returned
3494 with a request to reformat the changes.
3500 Since the number of patches for U-Boot is growing, we need to
3501 establish some rules. Submissions which do not conform to these rules
3502 may be rejected, even when they contain important and valuable stuff.
3504 Patches shall be sent to the u-boot-users mailing list.
3506 When you send a patch, please include the following information with
3509 * For bug fixes: a description of the bug and how your patch fixes
3510 this bug. Please try to include a way of demonstrating that the
3511 patch actually fixes something.
3513 * For new features: a description of the feature and your
3516 * A CHANGELOG entry as plaintext (separate from the patch)
3518 * For major contributions, your entry to the CREDITS file
3520 * When you add support for a new board, don't forget to add this
3521 board to the MAKEALL script, too.
3523 * If your patch adds new configuration options, don't forget to
3524 document these in the README file.
3526 * The patch itself. If you are accessing the CVS repository use "cvs
3527 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3528 version of diff does not support these options, then get the latest
3529 version of GNU diff.
3531 The current directory when running this command shall be the top
3532 level directory of the U-Boot source tree, or it's parent directory
3533 (i. e. please make sure that your patch includes sufficient
3534 directory information for the affected files).
3536 We accept patches as plain text, MIME attachments or as uuencoded
3539 * If one logical set of modifications affects or creates several
3540 files, all these changes shall be submitted in a SINGLE patch file.
3542 * Changesets that contain different, unrelated modifications shall be
3543 submitted as SEPARATE patches, one patch per changeset.
3548 * Before sending the patch, run the MAKEALL script on your patched
3549 source tree and make sure that no errors or warnings are reported
3550 for any of the boards.
3552 * Keep your modifications to the necessary minimum: A patch
3553 containing several unrelated changes or arbitrary reformats will be
3554 returned with a request to re-formatting / split it.
3556 * If you modify existing code, make sure that your new code does not
3557 add to the memory footprint of the code ;-) Small is beautiful!
3558 When adding new features, these should compile conditionally only
3559 (using #ifdef), and the resulting code with the new feature
3560 disabled must not need more memory than the old code without your
3563 * Remember that there is a size limit of 40 kB per message on the
3564 u-boot-users mailing list. Compression may help.
projects / oweals / u-boot.git / blob