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_GEN860T CONFIG_PCI405
266 CONFIG_ADS860 CONFIG_GENIETV CONFIG_PCIPPC2
267 CONFIG_AMX860 CONFIG_GTH CONFIG_PCIPPC6
268 CONFIG_AP1000 CONFIG_gw8260 CONFIG_pcu_e
269 CONFIG_AR405 CONFIG_hermes CONFIG_PIP405
270 CONFIG_BAB7xx CONFIG_hymod CONFIG_PM826
271 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
272 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
273 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
274 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
275 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
276 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
277 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
278 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
279 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
280 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
281 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
282 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
283 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
284 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
285 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
286 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
287 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
288 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
289 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
290 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
291 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
292 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
293 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
294 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
295 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
296 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
297 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
298 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
299 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
300 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
301 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
302 CONFIG_FPS860L CONFIG_OXC
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_SHANNON, CONFIG_P2_OMAP730, CONFIG_SMDK2400,
314 CONFIG_SMDK2410, CONFIG_TRAB, CONFIG_VCMA9
316 MicroBlaze based boards:
317 ------------------------
322 ------------------------
324 CONFIG_PCI5441 CONFIG_PK1C20
327 - CPU Module Type: (if CONFIG_COGENT is defined)
328 Define exactly one of
330 --- FIXME --- not tested yet:
331 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
332 CONFIG_CMA287_23, CONFIG_CMA287_50
334 - Motherboard Type: (if CONFIG_COGENT is defined)
335 Define exactly one of
336 CONFIG_CMA101, CONFIG_CMA102
338 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
339 Define one or more of
342 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
343 Define one or more of
344 CONFIG_LCD_HEARTBEAT - update a character position on
345 the lcd display every second with
348 - Board flavour: (if CONFIG_MPC8260ADS is defined)
351 CFG_8260ADS - original MPC8260ADS
352 CFG_8266ADS - MPC8266ADS
353 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
354 CFG_8272ADS - MPC8272ADS
356 - MPC824X Family Member (if CONFIG_MPC824X is defined)
357 Define exactly one of
358 CONFIG_MPC8240, CONFIG_MPC8245
360 - 8xx CPU Options: (if using an MPC8xx cpu)
361 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
362 get_gclk_freq() cannot work
363 e.g. if there is no 32KHz
364 reference PIT/RTC clock
365 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
368 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
371 CONFIG_8xx_CPUCLK_DEFAULT
372 See doc/README.MPC866
376 Define this to measure the actual CPU clock instead
377 of relying on the correctness of the configured
378 values. Mostly useful for board bringup to make sure
379 the PLL is locked at the intended frequency. Note
380 that this requires a (stable) reference clock (32 kHz
381 RTC clock or CFG_8XX_XIN)
383 - Intel Monahans options:
384 CFG_MONAHANS_RUN_MODE_OSC_RATIO
386 Defines the Monahans run mode to oscillator
387 ratio. Valid values are 8, 16, 24, 31. The core
388 frequency is this value multiplied by 13 MHz.
390 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
392 Defines the Monahans turbo mode to oscillator
393 ratio. Valid values are 1 (default if undefined) and
394 2. The core frequency as calculated above is multiplied
397 - Linux Kernel Interface:
400 U-Boot stores all clock information in Hz
401 internally. For binary compatibility with older Linux
402 kernels (which expect the clocks passed in the
403 bd_info data to be in MHz) the environment variable
404 "clocks_in_mhz" can be defined so that U-Boot
405 converts clock data to MHZ before passing it to the
407 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
408 "clocks_in_mhz=1" is automatically included in the
411 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
413 When transfering memsize parameter to linux, some versions
414 expect it to be in bytes, others in MB.
415 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
419 New kernel versions are expecting firmware settings to be
420 passed using flat open firmware trees.
421 The environment variable "disable_of", when set, disables this
424 CONFIG_OF_FLAT_TREE_MAX_SIZE
426 The maximum size of the constructed OF tree.
428 OF_CPU - The proper name of the cpus node.
429 OF_SOC - The proper name of the soc node.
430 OF_TBCLK - The timebase frequency.
431 OF_STDOUT_PATH - The path to the console device
435 The resulting flat device tree will have a copy of the bd_t.
436 Space should be pre-allocated in the dts for the bd_t.
438 CONFIG_OF_HAS_UBOOT_ENV
440 The resulting flat device tree will have a copy of u-boot's
441 environment variables
443 CONFIG_OF_BOARD_SETUP
445 Board code has addition modification that it wants to make
446 to the flat device tree before handing it off to the kernel
451 Define this if you want support for Amba PrimeCell PL010 UARTs.
455 Define this if you want support for Amba PrimeCell PL011 UARTs.
459 If you have Amba PrimeCell PL011 UARTs, set this variable to
460 the clock speed of the UARTs.
464 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
465 define this to a list of base addresses for each (supported)
466 port. See e.g. include/configs/versatile.h
470 Depending on board, define exactly one serial port
471 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
472 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
473 console by defining CONFIG_8xx_CONS_NONE
475 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
476 port routines must be defined elsewhere
477 (i.e. serial_init(), serial_getc(), ...)
480 Enables console device for a color framebuffer. Needs following
481 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
482 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
484 VIDEO_HW_RECTFILL graphic chip supports
487 VIDEO_HW_BITBLT graphic chip supports
488 bit-blit (cf. smiLynxEM)
489 VIDEO_VISIBLE_COLS visible pixel columns
491 VIDEO_VISIBLE_ROWS visible pixel rows
492 VIDEO_PIXEL_SIZE bytes per pixel
493 VIDEO_DATA_FORMAT graphic data format
494 (0-5, cf. cfb_console.c)
495 VIDEO_FB_ADRS framebuffer address
496 VIDEO_KBD_INIT_FCT keyboard int fct
497 (i.e. i8042_kbd_init())
498 VIDEO_TSTC_FCT test char fct
500 VIDEO_GETC_FCT get char fct
502 CONFIG_CONSOLE_CURSOR cursor drawing on/off
503 (requires blink timer
505 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
506 CONFIG_CONSOLE_TIME display time/date info in
508 (requires CFG_CMD_DATE)
509 CONFIG_VIDEO_LOGO display Linux logo in
511 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
512 linux_logo.h for logo.
513 Requires CONFIG_VIDEO_LOGO
514 CONFIG_CONSOLE_EXTRA_INFO
515 addional board info beside
518 When CONFIG_CFB_CONSOLE is defined, video console is
519 default i/o. Serial console can be forced with
520 environment 'console=serial'.
522 When CONFIG_SILENT_CONSOLE is defined, all console
523 messages (by U-Boot and Linux!) can be silenced with
524 the "silent" environment variable. See
525 doc/README.silent for more information.
528 CONFIG_BAUDRATE - in bps
529 Select one of the baudrates listed in
530 CFG_BAUDRATE_TABLE, see below.
531 CFG_BRGCLK_PRESCALE, baudrate prescale
533 - Interrupt driven serial port input:
534 CONFIG_SERIAL_SOFTWARE_FIFO
537 Use an interrupt handler for receiving data on the
538 serial port. It also enables using hardware handshake
539 (RTS/CTS) and UART's built-in FIFO. Set the number of
540 bytes the interrupt driven input buffer should have.
542 Leave undefined to disable this feature, including
543 disable the buffer and hardware handshake.
545 - Console UART Number:
549 If defined internal UART1 (and not UART0) is used
550 as default U-Boot console.
552 - Boot Delay: CONFIG_BOOTDELAY - in seconds
553 Delay before automatically booting the default image;
554 set to -1 to disable autoboot.
556 See doc/README.autoboot for these options that
557 work with CONFIG_BOOTDELAY. None are required.
558 CONFIG_BOOT_RETRY_TIME
559 CONFIG_BOOT_RETRY_MIN
560 CONFIG_AUTOBOOT_KEYED
561 CONFIG_AUTOBOOT_PROMPT
562 CONFIG_AUTOBOOT_DELAY_STR
563 CONFIG_AUTOBOOT_STOP_STR
564 CONFIG_AUTOBOOT_DELAY_STR2
565 CONFIG_AUTOBOOT_STOP_STR2
566 CONFIG_ZERO_BOOTDELAY_CHECK
567 CONFIG_RESET_TO_RETRY
571 Only needed when CONFIG_BOOTDELAY is enabled;
572 define a command string that is automatically executed
573 when no character is read on the console interface
574 within "Boot Delay" after reset.
577 This can be used to pass arguments to the bootm
578 command. The value of CONFIG_BOOTARGS goes into the
579 environment value "bootargs".
581 CONFIG_RAMBOOT and CONFIG_NFSBOOT
582 The value of these goes into the environment as
583 "ramboot" and "nfsboot" respectively, and can be used
584 as a convenience, when switching between booting from
590 When this option is #defined, the existence of the
591 environment variable "preboot" will be checked
592 immediately before starting the CONFIG_BOOTDELAY
593 countdown and/or running the auto-boot command resp.
594 entering interactive mode.
596 This feature is especially useful when "preboot" is
597 automatically generated or modified. For an example
598 see the LWMON board specific code: here "preboot" is
599 modified when the user holds down a certain
600 combination of keys on the (special) keyboard when
603 - Serial Download Echo Mode:
605 If defined to 1, all characters received during a
606 serial download (using the "loads" command) are
607 echoed back. This might be needed by some terminal
608 emulations (like "cu"), but may as well just take
609 time on others. This setting #define's the initial
610 value of the "loads_echo" environment variable.
612 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
614 Select one of the baudrates listed in
615 CFG_BAUDRATE_TABLE, see below.
619 Most monitor functions can be selected (or
620 de-selected) by adjusting the definition of
621 CONFIG_COMMANDS; to select individual functions,
622 #define CONFIG_COMMANDS by "OR"ing any of the
625 #define enables commands:
626 -------------------------
627 CFG_CMD_ASKENV * ask for env variable
628 CFG_CMD_AUTOSCRIPT Autoscript Support
630 CFG_CMD_BEDBUG * Include BedBug Debugger
631 CFG_CMD_BMP * BMP support
632 CFG_CMD_BSP * Board specific commands
634 CFG_CMD_CACHE * icache, dcache
635 CFG_CMD_CONSOLE coninfo
636 CFG_CMD_DATE * support for RTC, date/time...
637 CFG_CMD_DHCP * DHCP support
638 CFG_CMD_DIAG * Diagnostics
639 CFG_CMD_DOC * Disk-On-Chip Support
640 CFG_CMD_DTT * Digital Therm and Thermostat
641 CFG_CMD_ECHO echo arguments
642 CFG_CMD_EEPROM * EEPROM read/write support
643 CFG_CMD_ELF * bootelf, bootvx
645 CFG_CMD_FDC * Floppy Disk Support
646 CFG_CMD_FAT * FAT partition support
647 CFG_CMD_FDOS * Dos diskette Support
648 CFG_CMD_FLASH flinfo, erase, protect
649 CFG_CMD_FPGA FPGA device initialization support
650 CFG_CMD_HWFLOW * RTS/CTS hw flow control
651 CFG_CMD_I2C * I2C serial bus support
652 CFG_CMD_IDE * IDE harddisk support
654 CFG_CMD_IMLS List all found images
655 CFG_CMD_IMMAP * IMMR dump support
656 CFG_CMD_IRQ * irqinfo
657 CFG_CMD_ITEST Integer/string test of 2 values
658 CFG_CMD_JFFS2 * JFFS2 Support
662 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
664 CFG_CMD_MISC Misc functions like sleep etc
665 CFG_CMD_MMC * MMC memory mapped support
666 CFG_CMD_MII * MII utility commands
667 CFG_CMD_NAND * NAND support
668 CFG_CMD_NET bootp, tftpboot, rarpboot
669 CFG_CMD_PCI * pciinfo
670 CFG_CMD_PCMCIA * PCMCIA support
671 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
672 CFG_CMD_PORTIO * Port I/O
673 CFG_CMD_REGINFO * Register dump
674 CFG_CMD_RUN run command in env variable
675 CFG_CMD_SAVES * save S record dump
676 CFG_CMD_SCSI * SCSI Support
677 CFG_CMD_SDRAM * print SDRAM configuration information
678 (requires CFG_CMD_I2C)
679 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
680 CFG_CMD_SPI * SPI serial bus support
681 CFG_CMD_USB * USB support
682 CFG_CMD_VFD * VFD support (TRAB)
683 CFG_CMD_BSP * Board SPecific functions
684 CFG_CMD_CDP * Cisco Discover Protocol support
685 -----------------------------------------------
688 CONFIG_CMD_DFL Default configuration; at the moment
689 this is includes all commands, except
690 the ones marked with "*" in the list
693 If you don't define CONFIG_COMMANDS it defaults to
694 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
695 override the default settings in the respective
698 EXAMPLE: If you want all functions except of network
699 support you can write:
701 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
704 Note: Don't enable the "icache" and "dcache" commands
705 (configuration option CFG_CMD_CACHE) unless you know
706 what you (and your U-Boot users) are doing. Data
707 cache cannot be enabled on systems like the 8xx or
708 8260 (where accesses to the IMMR region must be
709 uncached), and it cannot be disabled on all other
710 systems where we (mis-) use the data cache to hold an
711 initial stack and some data.
714 XXX - this list needs to get updated!
718 If this variable is defined, it enables watchdog
719 support. There must be support in the platform specific
720 code for a watchdog. For the 8xx and 8260 CPUs, the
721 SIU Watchdog feature is enabled in the SYPCR
725 CONFIG_VERSION_VARIABLE
726 If this variable is defined, an environment variable
727 named "ver" is created by U-Boot showing the U-Boot
728 version as printed by the "version" command.
729 This variable is readonly.
733 When CFG_CMD_DATE is selected, the type of the RTC
734 has to be selected, too. Define exactly one of the
737 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
738 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
739 CONFIG_RTC_MC146818 - use MC146818 RTC
740 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
741 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
742 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
743 CONFIG_RTC_DS164x - use Dallas DS164x RTC
744 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
746 Note that if the RTC uses I2C, then the I2C interface
747 must also be configured. See I2C Support, below.
751 When CONFIG_TIMESTAMP is selected, the timestamp
752 (date and time) of an image is printed by image
753 commands like bootm or iminfo. This option is
754 automatically enabled when you select CFG_CMD_DATE .
757 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
758 and/or CONFIG_ISO_PARTITION
760 If IDE or SCSI support is enabled (CFG_CMD_IDE or
761 CFG_CMD_SCSI) you must configure support for at least
762 one partition type as well.
765 CONFIG_IDE_RESET_ROUTINE - this is defined in several
766 board configurations files but used nowhere!
768 CONFIG_IDE_RESET - is this is defined, IDE Reset will
769 be performed by calling the function
770 ide_set_reset(int reset)
771 which has to be defined in a board specific file
776 Set this to enable ATAPI support.
781 Set this to enable support for disks larger than 137GB
782 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
783 Whithout these , LBA48 support uses 32bit variables and will 'only'
784 support disks up to 2.1TB.
787 When enabled, makes the IDE subsystem use 64bit sector addresses.
791 At the moment only there is only support for the
792 SYM53C8XX SCSI controller; define
793 CONFIG_SCSI_SYM53C8XX to enable it.
795 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
796 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
797 CFG_SCSI_MAX_LUN] can be adjusted to define the
798 maximum numbers of LUNs, SCSI ID's and target
800 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
802 - NETWORK Support (PCI):
804 Support for Intel 8254x gigabit chips.
807 Support for Intel 82557/82559/82559ER chips.
808 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
809 write routine for first time initialisation.
812 Support for Digital 2114x chips.
813 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
814 modem chip initialisation (KS8761/QS6611).
817 Support for National dp83815 chips.
820 Support for National dp8382[01] gigabit chips.
822 - NETWORK Support (other):
824 CONFIG_DRIVER_LAN91C96
825 Support for SMSC's LAN91C96 chips.
828 Define this to hold the physical address
829 of the LAN91C96's I/O space
831 CONFIG_LAN91C96_USE_32_BIT
832 Define this to enable 32 bit addressing
834 CONFIG_DRIVER_SMC91111
835 Support for SMSC's LAN91C111 chip
838 Define this to hold the physical address
839 of the device (I/O space)
841 CONFIG_SMC_USE_32_BIT
842 Define this if data bus is 32 bits
844 CONFIG_SMC_USE_IOFUNCS
845 Define this to use i/o functions instead of macros
846 (some hardware wont work with macros)
849 At the moment only the UHCI host controller is
850 supported (PIP405, MIP405, MPC5200); define
851 CONFIG_USB_UHCI to enable it.
852 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
853 and define CONFIG_USB_STORAGE to enable the USB
856 Supported are USB Keyboards and USB Floppy drives
858 MPC5200 USB requires additional defines:
860 for 528 MHz Clock: 0x0001bbbb
862 for differential drivers: 0x00001000
863 for single ended drivers: 0x00005000
867 The MMC controller on the Intel PXA is supported. To
868 enable this define CONFIG_MMC. The MMC can be
869 accessed from the boot prompt by mapping the device
870 to physical memory similar to flash. Command line is
871 enabled with CFG_CMD_MMC. The MMC driver also works with
872 the FAT fs. This is enabled with CFG_CMD_FAT.
874 - Journaling Flash filesystem support:
875 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
876 CONFIG_JFFS2_NAND_DEV
877 Define these for a default partition on a NAND device
879 CFG_JFFS2_FIRST_SECTOR,
880 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
881 Define these for a default partition on a NOR device
884 Define this to create an own partition. You have to provide a
885 function struct part_info* jffs2_part_info(int part_num)
887 If you define only one JFFS2 partition you may also want to
888 #define CFG_JFFS_SINGLE_PART 1
889 to disable the command chpart. This is the default when you
890 have not defined a custom partition
895 Define this to enable standard (PC-Style) keyboard
899 Standard PC keyboard driver with US (is default) and
900 GERMAN key layout (switch via environment 'keymap=de') support.
901 Export function i8042_kbd_init, i8042_tstc and i8042_getc
902 for cfb_console. Supports cursor blinking.
907 Define this to enable video support (for output to
912 Enable Chips & Technologies 69000 Video chip
914 CONFIG_VIDEO_SMI_LYNXEM
915 Enable Silicon Motion SMI 712/710/810 Video chip. The
916 video output is selected via environment 'videoout'
917 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
920 For the CT69000 and SMI_LYNXEM drivers, videomode is
921 selected via environment 'videomode'. Two diferent ways
923 - "videomode=num" 'num' is a standard LiLo mode numbers.
924 Following standard modes are supported (* is default):
926 Colors 640x480 800x600 1024x768 1152x864 1280x1024
927 -------------+---------------------------------------------
928 8 bits | 0x301* 0x303 0x305 0x161 0x307
929 15 bits | 0x310 0x313 0x316 0x162 0x319
930 16 bits | 0x311 0x314 0x317 0x163 0x31A
931 24 bits | 0x312 0x315 0x318 ? 0x31B
932 -------------+---------------------------------------------
933 (i.e. setenv videomode 317; saveenv; reset;)
935 - "videomode=bootargs" all the video parameters are parsed
936 from the bootargs. (See drivers/videomodes.c)
939 CONFIG_VIDEO_SED13806
940 Enable Epson SED13806 driver. This driver supports 8bpp
941 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
942 or CONFIG_VIDEO_SED13806_16BPP
947 Define this to enable a custom keyboard support.
948 This simply calls drv_keyboard_init() which must be
949 defined in your board-specific files.
950 The only board using this so far is RBC823.
952 - LCD Support: CONFIG_LCD
954 Define this to enable LCD support (for output to LCD
955 display); also select one of the supported displays
956 by defining one of these:
958 CONFIG_NEC_NL6448AC33:
960 NEC NL6448AC33-18. Active, color, single scan.
962 CONFIG_NEC_NL6448BC20
964 NEC NL6448BC20-08. 6.5", 640x480.
965 Active, color, single scan.
967 CONFIG_NEC_NL6448BC33_54
969 NEC NL6448BC33-54. 10.4", 640x480.
970 Active, color, single scan.
974 Sharp 320x240. Active, color, single scan.
975 It isn't 16x9, and I am not sure what it is.
977 CONFIG_SHARP_LQ64D341
979 Sharp LQ64D341 display, 640x480.
980 Active, color, single scan.
984 HLD1045 display, 640x480.
985 Active, color, single scan.
989 Optrex CBL50840-2 NF-FW 99 22 M5
991 Hitachi LMG6912RPFC-00T
995 320x240. Black & white.
997 Normally display is black on white background; define
998 CFG_WHITE_ON_BLACK to get it inverted.
1000 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1002 If this option is set, the environment is checked for
1003 a variable "splashimage". If found, the usual display
1004 of logo, copyright and system information on the LCD
1005 is suppressed and the BMP image at the address
1006 specified in "splashimage" is loaded instead. The
1007 console is redirected to the "nulldev", too. This
1008 allows for a "silent" boot where a splash screen is
1009 loaded very quickly after power-on.
1011 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1013 If this option is set, additionally to standard BMP
1014 images, gzipped BMP images can be displayed via the
1015 splashscreen support or the bmp command.
1017 - Compression support:
1020 If this option is set, support for bzip2 compressed
1021 images is included. If not, only uncompressed and gzip
1022 compressed images are supported.
1024 NOTE: the bzip2 algorithm requires a lot of RAM, so
1025 the malloc area (as defined by CFG_MALLOC_LEN) should
1031 The address of PHY on MII bus.
1033 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1035 The clock frequency of the MII bus
1039 If this option is set, support for speed/duplex
1040 detection of Gigabit PHY is included.
1042 CONFIG_PHY_RESET_DELAY
1044 Some PHY like Intel LXT971A need extra delay after
1045 reset before any MII register access is possible.
1046 For such PHY, set this option to the usec delay
1047 required. (minimum 300usec for LXT971A)
1049 CONFIG_PHY_CMD_DELAY (ppc4xx)
1051 Some PHY like Intel LXT971A need extra delay after
1052 command issued before MII status register can be read
1059 Define a default value for ethernet address to use
1060 for the respective ethernet interface, in case this
1061 is not determined automatically.
1066 Define a default value for the IP address to use for
1067 the default ethernet interface, in case this is not
1068 determined through e.g. bootp.
1070 - Server IP address:
1073 Defines a default value for theIP address of a TFTP
1074 server to contact when using the "tftboot" command.
1076 - BOOTP Recovery Mode:
1077 CONFIG_BOOTP_RANDOM_DELAY
1079 If you have many targets in a network that try to
1080 boot using BOOTP, you may want to avoid that all
1081 systems send out BOOTP requests at precisely the same
1082 moment (which would happen for instance at recovery
1083 from a power failure, when all systems will try to
1084 boot, thus flooding the BOOTP server. Defining
1085 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1086 inserted before sending out BOOTP requests. The
1087 following delays are insterted then:
1089 1st BOOTP request: delay 0 ... 1 sec
1090 2nd BOOTP request: delay 0 ... 2 sec
1091 3rd BOOTP request: delay 0 ... 4 sec
1093 BOOTP requests: delay 0 ... 8 sec
1095 - DHCP Advanced Options:
1098 You can fine tune the DHCP functionality by adding
1099 these flags to the CONFIG_BOOTP_MASK define:
1101 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1102 serverip from a DHCP server, it is possible that more
1103 than one DNS serverip is offered to the client.
1104 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1105 serverip will be stored in the additional environment
1106 variable "dnsip2". The first DNS serverip is always
1107 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1108 is added to the CONFIG_BOOTP_MASK.
1110 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1111 to do a dynamic update of a DNS server. To do this, they
1112 need the hostname of the DHCP requester.
1113 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1114 CONFIG_BOOTP_MASK, the content of the "hostname"
1115 environment variable is passed as option 12 to
1119 CONFIG_CDP_DEVICE_ID
1121 The device id used in CDP trigger frames.
1123 CONFIG_CDP_DEVICE_ID_PREFIX
1125 A two character string which is prefixed to the MAC address
1130 A printf format string which contains the ascii name of
1131 the port. Normally is set to "eth%d" which sets
1132 eth0 for the first ethernet, eth1 for the second etc.
1134 CONFIG_CDP_CAPABILITIES
1136 A 32bit integer which indicates the device capabilities;
1137 0x00000010 for a normal host which does not forwards.
1141 An ascii string containing the version of the software.
1145 An ascii string containing the name of the platform.
1149 A 32bit integer sent on the trigger.
1151 CONFIG_CDP_POWER_CONSUMPTION
1153 A 16bit integer containing the power consumption of the
1154 device in .1 of milliwatts.
1156 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1158 A byte containing the id of the VLAN.
1160 - Status LED: CONFIG_STATUS_LED
1162 Several configurations allow to display the current
1163 status using a LED. For instance, the LED will blink
1164 fast while running U-Boot code, stop blinking as
1165 soon as a reply to a BOOTP request was received, and
1166 start blinking slow once the Linux kernel is running
1167 (supported by a status LED driver in the Linux
1168 kernel). Defining CONFIG_STATUS_LED enables this
1171 - CAN Support: CONFIG_CAN_DRIVER
1173 Defining CONFIG_CAN_DRIVER enables CAN driver support
1174 on those systems that support this (optional)
1175 feature, like the TQM8xxL modules.
1177 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1179 These enable I2C serial bus commands. Defining either of
1180 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1181 include the appropriate I2C driver for the selected cpu.
1183 This will allow you to use i2c commands at the u-boot
1184 command line (as long as you set CFG_CMD_I2C in
1185 CONFIG_COMMANDS) and communicate with i2c based realtime
1186 clock chips. See common/cmd_i2c.c for a description of the
1187 command line interface.
1189 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
1191 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1192 bit-banging) driver instead of CPM or similar hardware
1195 There are several other quantities that must also be
1196 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1198 In both cases you will need to define CFG_I2C_SPEED
1199 to be the frequency (in Hz) at which you wish your i2c bus
1200 to run and CFG_I2C_SLAVE to be the address of this node (ie
1201 the cpu's i2c node address).
1203 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1204 sets the cpu up as a master node and so its address should
1205 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1206 p.16-473). So, set CFG_I2C_SLAVE to 0.
1208 That's all that's required for CONFIG_HARD_I2C.
1210 If you use the software i2c interface (CONFIG_SOFT_I2C)
1211 then the following macros need to be defined (examples are
1212 from include/configs/lwmon.h):
1216 (Optional). Any commands necessary to enable the I2C
1217 controller or configure ports.
1219 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1223 (Only for MPC8260 CPU). The I/O port to use (the code
1224 assumes both bits are on the same port). Valid values
1225 are 0..3 for ports A..D.
1229 The code necessary to make the I2C data line active
1230 (driven). If the data line is open collector, this
1233 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1237 The code necessary to make the I2C data line tri-stated
1238 (inactive). If the data line is open collector, this
1241 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1245 Code that returns TRUE if the I2C data line is high,
1248 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1252 If <bit> is TRUE, sets the I2C data line high. If it
1253 is FALSE, it clears it (low).
1255 eg: #define I2C_SDA(bit) \
1256 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1257 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1261 If <bit> is TRUE, sets the I2C clock line high. If it
1262 is FALSE, it clears it (low).
1264 eg: #define I2C_SCL(bit) \
1265 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1266 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1270 This delay is invoked four times per clock cycle so this
1271 controls the rate of data transfer. The data rate thus
1272 is 1 / (I2C_DELAY * 4). Often defined to be something
1275 #define I2C_DELAY udelay(2)
1279 When a board is reset during an i2c bus transfer
1280 chips might think that the current transfer is still
1281 in progress. On some boards it is possible to access
1282 the i2c SCLK line directly, either by using the
1283 processor pin as a GPIO or by having a second pin
1284 connected to the bus. If this option is defined a
1285 custom i2c_init_board() routine in boards/xxx/board.c
1286 is run early in the boot sequence.
1288 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1290 This option enables configuration of bi_iic_fast[] flags
1291 in u-boot bd_info structure based on u-boot environment
1292 variable "i2cfast". (see also i2cfast)
1294 - SPI Support: CONFIG_SPI
1296 Enables SPI driver (so far only tested with
1297 SPI EEPROM, also an instance works with Crystal A/D and
1298 D/As on the SACSng board)
1302 Enables extended (16-bit) SPI EEPROM addressing.
1303 (symmetrical to CONFIG_I2C_X)
1307 Enables a software (bit-bang) SPI driver rather than
1308 using hardware support. This is a general purpose
1309 driver that only requires three general I/O port pins
1310 (two outputs, one input) to function. If this is
1311 defined, the board configuration must define several
1312 SPI configuration items (port pins to use, etc). For
1313 an example, see include/configs/sacsng.h.
1315 - FPGA Support: CONFIG_FPGA_COUNT
1317 Specify the number of FPGA devices to support.
1321 Used to specify the types of FPGA devices. For example,
1322 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1324 CFG_FPGA_PROG_FEEDBACK
1326 Enable printing of hash marks during FPGA configuration.
1330 Enable checks on FPGA configuration interface busy
1331 status by the configuration function. This option
1332 will require a board or device specific function to
1337 If defined, a function that provides delays in the FPGA
1338 configuration driver.
1340 CFG_FPGA_CHECK_CTRLC
1341 Allow Control-C to interrupt FPGA configuration
1343 CFG_FPGA_CHECK_ERROR
1345 Check for configuration errors during FPGA bitfile
1346 loading. For example, abort during Virtex II
1347 configuration if the INIT_B line goes low (which
1348 indicated a CRC error).
1352 Maximum time to wait for the INIT_B line to deassert
1353 after PROB_B has been deasserted during a Virtex II
1354 FPGA configuration sequence. The default time is 500
1359 Maximum time to wait for BUSY to deassert during
1360 Virtex II FPGA configuration. The default is 5 mS.
1362 CFG_FPGA_WAIT_CONFIG
1364 Time to wait after FPGA configuration. The default is
1367 - Configuration Management:
1370 If defined, this string will be added to the U-Boot
1371 version information (U_BOOT_VERSION)
1373 - Vendor Parameter Protection:
1375 U-Boot considers the values of the environment
1376 variables "serial#" (Board Serial Number) and
1377 "ethaddr" (Ethernet Address) to be parameters that
1378 are set once by the board vendor / manufacturer, and
1379 protects these variables from casual modification by
1380 the user. Once set, these variables are read-only,
1381 and write or delete attempts are rejected. You can
1382 change this behviour:
1384 If CONFIG_ENV_OVERWRITE is #defined in your config
1385 file, the write protection for vendor parameters is
1386 completely disabled. Anybody can change or delete
1389 Alternatively, if you #define _both_ CONFIG_ETHADDR
1390 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1391 ethernet address is installed in the environment,
1392 which can be changed exactly ONCE by the user. [The
1393 serial# is unaffected by this, i. e. it remains
1399 Define this variable to enable the reservation of
1400 "protected RAM", i. e. RAM which is not overwritten
1401 by U-Boot. Define CONFIG_PRAM to hold the number of
1402 kB you want to reserve for pRAM. You can overwrite
1403 this default value by defining an environment
1404 variable "pram" to the number of kB you want to
1405 reserve. Note that the board info structure will
1406 still show the full amount of RAM. If pRAM is
1407 reserved, a new environment variable "mem" will
1408 automatically be defined to hold the amount of
1409 remaining RAM in a form that can be passed as boot
1410 argument to Linux, for instance like that:
1412 setenv bootargs ... mem=\${mem}
1415 This way you can tell Linux not to use this memory,
1416 either, which results in a memory region that will
1417 not be affected by reboots.
1419 *WARNING* If your board configuration uses automatic
1420 detection of the RAM size, you must make sure that
1421 this memory test is non-destructive. So far, the
1422 following board configurations are known to be
1425 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1426 HERMES, IP860, RPXlite, LWMON, LANTEC,
1427 PCU_E, FLAGADM, TQM8260
1432 Define this variable to stop the system in case of a
1433 fatal error, so that you have to reset it manually.
1434 This is probably NOT a good idea for an embedded
1435 system where you want to system to reboot
1436 automatically as fast as possible, but it may be
1437 useful during development since you can try to debug
1438 the conditions that lead to the situation.
1440 CONFIG_NET_RETRY_COUNT
1442 This variable defines the number of retries for
1443 network operations like ARP, RARP, TFTP, or BOOTP
1444 before giving up the operation. If not defined, a
1445 default value of 5 is used.
1447 - Command Interpreter:
1450 Enable auto completion of commands using TAB.
1454 Define this variable to enable the "hush" shell (from
1455 Busybox) as command line interpreter, thus enabling
1456 powerful command line syntax like
1457 if...then...else...fi conditionals or `&&' and '||'
1458 constructs ("shell scripts").
1460 If undefined, you get the old, much simpler behaviour
1461 with a somewhat smaller memory footprint.
1466 This defines the secondary prompt string, which is
1467 printed when the command interpreter needs more input
1468 to complete a command. Usually "> ".
1472 In the current implementation, the local variables
1473 space and global environment variables space are
1474 separated. Local variables are those you define by
1475 simply typing `name=value'. To access a local
1476 variable later on, you have write `$name' or
1477 `${name}'; to execute the contents of a variable
1478 directly type `$name' at the command prompt.
1480 Global environment variables are those you use
1481 setenv/printenv to work with. To run a command stored
1482 in such a variable, you need to use the run command,
1483 and you must not use the '$' sign to access them.
1485 To store commands and special characters in a
1486 variable, please use double quotation marks
1487 surrounding the whole text of the variable, instead
1488 of the backslashes before semicolons and special
1491 - Default Environment:
1492 CONFIG_EXTRA_ENV_SETTINGS
1494 Define this to contain any number of null terminated
1495 strings (variable = value pairs) that will be part of
1496 the default environment compiled into the boot image.
1498 For example, place something like this in your
1499 board's config file:
1501 #define CONFIG_EXTRA_ENV_SETTINGS \
1505 Warning: This method is based on knowledge about the
1506 internal format how the environment is stored by the
1507 U-Boot code. This is NOT an official, exported
1508 interface! Although it is unlikely that this format
1509 will change soon, there is no guarantee either.
1510 You better know what you are doing here.
1512 Note: overly (ab)use of the default environment is
1513 discouraged. Make sure to check other ways to preset
1514 the environment like the autoscript function or the
1517 - DataFlash Support:
1518 CONFIG_HAS_DATAFLASH
1520 Defining this option enables DataFlash features and
1521 allows to read/write in Dataflash via the standard
1524 - SystemACE Support:
1527 Adding this option adds support for Xilinx SystemACE
1528 chips attached via some sort of local bus. The address
1529 of the chip must alsh be defined in the
1530 CFG_SYSTEMACE_BASE macro. For example:
1532 #define CONFIG_SYSTEMACE
1533 #define CFG_SYSTEMACE_BASE 0xf0000000
1535 When SystemACE support is added, the "ace" device type
1536 becomes available to the fat commands, i.e. fatls.
1538 - TFTP Fixed UDP Port:
1541 If this is defined, the environment variable tftpsrcp
1542 is used to supply the TFTP UDP source port value.
1543 If tftpsrcp isn't defined, the normal pseudo-random port
1544 number generator is used.
1546 Also, the environment variable tftpdstp is used to supply
1547 the TFTP UDP destination port value. If tftpdstp isn't
1548 defined, the normal port 69 is used.
1550 The purpose for tftpsrcp is to allow a TFTP server to
1551 blindly start the TFTP transfer using the pre-configured
1552 target IP address and UDP port. This has the effect of
1553 "punching through" the (Windows XP) firewall, allowing
1554 the remainder of the TFTP transfer to proceed normally.
1555 A better solution is to properly configure the firewall,
1556 but sometimes that is not allowed.
1558 - Show boot progress:
1559 CONFIG_SHOW_BOOT_PROGRESS
1561 Defining this option allows to add some board-
1562 specific code (calling a user-provided function
1563 "show_boot_progress(int)") that enables you to show
1564 the system's boot progress on some display (for
1565 example, some LED's) on your board. At the moment,
1566 the following checkpoints are implemented:
1569 1 common/cmd_bootm.c before attempting to boot an image
1570 -1 common/cmd_bootm.c Image header has bad magic number
1571 2 common/cmd_bootm.c Image header has correct magic number
1572 -2 common/cmd_bootm.c Image header has bad checksum
1573 3 common/cmd_bootm.c Image header has correct checksum
1574 -3 common/cmd_bootm.c Image data has bad checksum
1575 4 common/cmd_bootm.c Image data has correct checksum
1576 -4 common/cmd_bootm.c Image is for unsupported architecture
1577 5 common/cmd_bootm.c Architecture check OK
1578 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1579 6 common/cmd_bootm.c Image Type check OK
1580 -6 common/cmd_bootm.c gunzip uncompression error
1581 -7 common/cmd_bootm.c Unimplemented compression type
1582 7 common/cmd_bootm.c Uncompression OK
1583 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1584 8 common/cmd_bootm.c Image Type check OK
1585 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1586 9 common/cmd_bootm.c Start initial ramdisk verification
1587 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1588 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1589 10 common/cmd_bootm.c Ramdisk header is OK
1590 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1591 11 common/cmd_bootm.c Ramdisk data has correct checksum
1592 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1593 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1594 13 common/cmd_bootm.c Start multifile image verification
1595 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1596 15 common/cmd_bootm.c All preparation done, transferring control to OS
1598 -30 lib_ppc/board.c Fatal error, hang the system
1599 -31 post/post.c POST test failed, detected by post_output_backlog()
1600 -32 post/post.c POST test failed, detected by post_run_single()
1602 -1 common/cmd_doc.c Bad usage of "doc" command
1603 -1 common/cmd_doc.c No boot device
1604 -1 common/cmd_doc.c Unknown Chip ID on boot device
1605 -1 common/cmd_doc.c Read Error on boot device
1606 -1 common/cmd_doc.c Image header has bad magic number
1608 -1 common/cmd_ide.c Bad usage of "ide" command
1609 -1 common/cmd_ide.c No boot device
1610 -1 common/cmd_ide.c Unknown boot device
1611 -1 common/cmd_ide.c Unknown partition table
1612 -1 common/cmd_ide.c Invalid partition type
1613 -1 common/cmd_ide.c Read Error on boot device
1614 -1 common/cmd_ide.c Image header has bad magic number
1616 -1 common/cmd_nand.c Bad usage of "nand" command
1617 -1 common/cmd_nand.c No boot device
1618 -1 common/cmd_nand.c Unknown Chip ID on boot device
1619 -1 common/cmd_nand.c Read Error on boot device
1620 -1 common/cmd_nand.c Image header has bad magic number
1622 -1 common/env_common.c Environment has a bad CRC, using default
1628 [so far only for SMDK2400 and TRAB boards]
1630 - Modem support endable:
1631 CONFIG_MODEM_SUPPORT
1633 - RTS/CTS Flow control enable:
1636 - Modem debug support:
1637 CONFIG_MODEM_SUPPORT_DEBUG
1639 Enables debugging stuff (char screen[1024], dbg())
1640 for modem support. Useful only with BDI2000.
1642 - Interrupt support (PPC):
1644 There are common interrupt_init() and timer_interrupt()
1645 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1646 for cpu specific initialization. interrupt_init_cpu()
1647 should set decrementer_count to appropriate value. If
1648 cpu resets decrementer automatically after interrupt
1649 (ppc4xx) it should set decrementer_count to zero.
1650 timer_interrupt() calls timer_interrupt_cpu() for cpu
1651 specific handling. If board has watchdog / status_led
1652 / other_activity_monitor it works automatically from
1653 general timer_interrupt().
1657 In the target system modem support is enabled when a
1658 specific key (key combination) is pressed during
1659 power-on. Otherwise U-Boot will boot normally
1660 (autoboot). The key_pressed() fuction is called from
1661 board_init(). Currently key_pressed() is a dummy
1662 function, returning 1 and thus enabling modem
1665 If there are no modem init strings in the
1666 environment, U-Boot proceed to autoboot; the
1667 previous output (banner, info printfs) will be
1670 See also: doc/README.Modem
1673 Configuration Settings:
1674 -----------------------
1676 - CFG_LONGHELP: Defined when you want long help messages included;
1677 undefine this when you're short of memory.
1679 - CFG_PROMPT: This is what U-Boot prints on the console to
1680 prompt for user input.
1682 - CFG_CBSIZE: Buffer size for input from the Console
1684 - CFG_PBSIZE: Buffer size for Console output
1686 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1688 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1689 the application (usually a Linux kernel) when it is
1692 - CFG_BAUDRATE_TABLE:
1693 List of legal baudrate settings for this board.
1695 - CFG_CONSOLE_INFO_QUIET
1696 Suppress display of console information at boot.
1698 - CFG_CONSOLE_IS_IN_ENV
1699 If the board specific function
1700 extern int overwrite_console (void);
1701 returns 1, the stdin, stderr and stdout are switched to the
1702 serial port, else the settings in the environment are used.
1704 - CFG_CONSOLE_OVERWRITE_ROUTINE
1705 Enable the call to overwrite_console().
1707 - CFG_CONSOLE_ENV_OVERWRITE
1708 Enable overwrite of previous console environment settings.
1710 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1711 Begin and End addresses of the area used by the
1715 Enable an alternate, more extensive memory test.
1717 - CFG_MEMTEST_SCRATCH:
1718 Scratch address used by the alternate memory test
1719 You only need to set this if address zero isn't writeable
1721 - CFG_TFTP_LOADADDR:
1722 Default load address for network file downloads
1724 - CFG_LOADS_BAUD_CHANGE:
1725 Enable temporary baudrate change while serial download
1728 Physical start address of SDRAM. _Must_ be 0 here.
1731 Physical start address of Motherboard I/O (if using a
1735 Physical start address of Flash memory.
1738 Physical start address of boot monitor code (set by
1739 make config files to be same as the text base address
1740 (TEXT_BASE) used when linking) - same as
1741 CFG_FLASH_BASE when booting from flash.
1744 Size of memory reserved for monitor code, used to
1745 determine _at_compile_time_ (!) if the environment is
1746 embedded within the U-Boot image, or in a separate
1750 Size of DRAM reserved for malloc() use.
1753 Normally compressed uImages are limited to an
1754 uncompressed size of 8 MBytes. If this is not enough,
1755 you can define CFG_BOOTM_LEN in your board config file
1756 to adjust this setting to your needs.
1759 Maximum size of memory mapped by the startup code of
1760 the Linux kernel; all data that must be processed by
1761 the Linux kernel (bd_info, boot arguments, eventually
1762 initrd image) must be put below this limit.
1764 - CFG_MAX_FLASH_BANKS:
1765 Max number of Flash memory banks
1767 - CFG_MAX_FLASH_SECT:
1768 Max number of sectors on a Flash chip
1770 - CFG_FLASH_ERASE_TOUT:
1771 Timeout for Flash erase operations (in ms)
1773 - CFG_FLASH_WRITE_TOUT:
1774 Timeout for Flash write operations (in ms)
1776 - CFG_FLASH_LOCK_TOUT
1777 Timeout for Flash set sector lock bit operation (in ms)
1779 - CFG_FLASH_UNLOCK_TOUT
1780 Timeout for Flash clear lock bits operation (in ms)
1782 - CFG_FLASH_PROTECTION
1783 If defined, hardware flash sectors protection is used
1784 instead of U-Boot software protection.
1786 - CFG_DIRECT_FLASH_TFTP:
1788 Enable TFTP transfers directly to flash memory;
1789 without this option such a download has to be
1790 performed in two steps: (1) download to RAM, and (2)
1791 copy from RAM to flash.
1793 The two-step approach is usually more reliable, since
1794 you can check if the download worked before you erase
1795 the flash, but in some situations (when sytem RAM is
1796 too limited to allow for a tempory copy of the
1797 downloaded image) this option may be very useful.
1800 Define if the flash driver uses extra elements in the
1801 common flash structure for storing flash geometry.
1803 - CFG_FLASH_CFI_DRIVER
1804 This option also enables the building of the cfi_flash driver
1805 in the drivers directory
1807 - CFG_FLASH_QUIET_TEST
1808 If this option is defined, the common CFI flash doesn't
1809 print it's warning upon not recognized FLASH banks. This
1810 is useful, if some of the configured banks are only
1811 optionally available.
1813 - CFG_RX_ETH_BUFFER:
1814 Defines the number of ethernet receive buffers. On some
1815 ethernet controllers it is recommended to set this value
1816 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1817 buffers can be full shortly after enabling the interface
1818 on high ethernet traffic.
1819 Defaults to 4 if not defined.
1821 The following definitions that deal with the placement and management
1822 of environment data (variable area); in general, we support the
1823 following configurations:
1825 - CFG_ENV_IS_IN_FLASH:
1827 Define this if the environment is in flash memory.
1829 a) The environment occupies one whole flash sector, which is
1830 "embedded" in the text segment with the U-Boot code. This
1831 happens usually with "bottom boot sector" or "top boot
1832 sector" type flash chips, which have several smaller
1833 sectors at the start or the end. For instance, such a
1834 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1835 such a case you would place the environment in one of the
1836 4 kB sectors - with U-Boot code before and after it. With
1837 "top boot sector" type flash chips, you would put the
1838 environment in one of the last sectors, leaving a gap
1839 between U-Boot and the environment.
1843 Offset of environment data (variable area) to the
1844 beginning of flash memory; for instance, with bottom boot
1845 type flash chips the second sector can be used: the offset
1846 for this sector is given here.
1848 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1852 This is just another way to specify the start address of
1853 the flash sector containing the environment (instead of
1856 - CFG_ENV_SECT_SIZE:
1858 Size of the sector containing the environment.
1861 b) Sometimes flash chips have few, equal sized, BIG sectors.
1862 In such a case you don't want to spend a whole sector for
1867 If you use this in combination with CFG_ENV_IS_IN_FLASH
1868 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1869 of this flash sector for the environment. This saves
1870 memory for the RAM copy of the environment.
1872 It may also save flash memory if you decide to use this
1873 when your environment is "embedded" within U-Boot code,
1874 since then the remainder of the flash sector could be used
1875 for U-Boot code. It should be pointed out that this is
1876 STRONGLY DISCOURAGED from a robustness point of view:
1877 updating the environment in flash makes it always
1878 necessary to erase the WHOLE sector. If something goes
1879 wrong before the contents has been restored from a copy in
1880 RAM, your target system will be dead.
1882 - CFG_ENV_ADDR_REDUND
1885 These settings describe a second storage area used to hold
1886 a redundand copy of the environment data, so that there is
1887 a valid backup copy in case there is a power failure during
1888 a "saveenv" operation.
1890 BE CAREFUL! Any changes to the flash layout, and some changes to the
1891 source code will make it necessary to adapt <board>/u-boot.lds*
1895 - CFG_ENV_IS_IN_NVRAM:
1897 Define this if you have some non-volatile memory device
1898 (NVRAM, battery buffered SRAM) which you want to use for the
1904 These two #defines are used to determin the memory area you
1905 want to use for environment. It is assumed that this memory
1906 can just be read and written to, without any special
1909 BE CAREFUL! The first access to the environment happens quite early
1910 in U-Boot initalization (when we try to get the setting of for the
1911 console baudrate). You *MUST* have mappend your NVRAM area then, or
1914 Please note that even with NVRAM we still use a copy of the
1915 environment in RAM: we could work on NVRAM directly, but we want to
1916 keep settings there always unmodified except somebody uses "saveenv"
1917 to save the current settings.
1920 - CFG_ENV_IS_IN_EEPROM:
1922 Use this if you have an EEPROM or similar serial access
1923 device and a driver for it.
1928 These two #defines specify the offset and size of the
1929 environment area within the total memory of your EEPROM.
1931 - CFG_I2C_EEPROM_ADDR:
1932 If defined, specified the chip address of the EEPROM device.
1933 The default address is zero.
1935 - CFG_EEPROM_PAGE_WRITE_BITS:
1936 If defined, the number of bits used to address bytes in a
1937 single page in the EEPROM device. A 64 byte page, for example
1938 would require six bits.
1940 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1941 If defined, the number of milliseconds to delay between
1942 page writes. The default is zero milliseconds.
1944 - CFG_I2C_EEPROM_ADDR_LEN:
1945 The length in bytes of the EEPROM memory array address. Note
1946 that this is NOT the chip address length!
1948 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
1949 EEPROM chips that implement "address overflow" are ones
1950 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
1951 address and the extra bits end up in the "chip address" bit
1952 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
1955 Note that we consider the length of the address field to
1956 still be one byte because the extra address bits are hidden
1957 in the chip address.
1960 The size in bytes of the EEPROM device.
1963 - CFG_ENV_IS_IN_DATAFLASH:
1965 Define this if you have a DataFlash memory device which you
1966 want to use for the environment.
1972 These three #defines specify the offset and size of the
1973 environment area within the total memory of your DataFlash placed
1974 at the specified address.
1976 - CFG_ENV_IS_IN_NAND:
1978 Define this if you have a NAND device which you want to use
1979 for the environment.
1984 These two #defines specify the offset and size of the environment
1985 area within the first NAND device.
1987 - CFG_ENV_OFFSET_REDUND
1989 This setting describes a second storage area of CFG_ENV_SIZE
1990 size used to hold a redundant copy of the environment data,
1991 so that there is a valid backup copy in case there is a
1992 power failure during a "saveenv" operation.
1994 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
1995 to a block boundary, and CFG_ENV_SIZE must be a multiple of
1996 the NAND devices block size.
1998 - CFG_SPI_INIT_OFFSET
2000 Defines offset to the initial SPI buffer area in DPRAM. The
2001 area is used at an early stage (ROM part) if the environment
2002 is configured to reside in the SPI EEPROM: We need a 520 byte
2003 scratch DPRAM area. It is used between the two initialization
2004 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2005 to be a good choice since it makes it far enough from the
2006 start of the data area as well as from the stack pointer.
2008 Please note that the environment is read-only as long as the monitor
2009 has been relocated to RAM and a RAM copy of the environment has been
2010 created; also, when using EEPROM you will have to use getenv_r()
2011 until then to read environment variables.
2013 The environment is protected by a CRC32 checksum. Before the monitor
2014 is relocated into RAM, as a result of a bad CRC you will be working
2015 with the compiled-in default environment - *silently*!!! [This is
2016 necessary, because the first environment variable we need is the
2017 "baudrate" setting for the console - if we have a bad CRC, we don't
2018 have any device yet where we could complain.]
2020 Note: once the monitor has been relocated, then it will complain if
2021 the default environment is used; a new CRC is computed as soon as you
2022 use the "saveenv" command to store a valid environment.
2024 - CFG_FAULT_ECHO_LINK_DOWN:
2025 Echo the inverted Ethernet link state to the fault LED.
2027 Note: If this option is active, then CFG_FAULT_MII_ADDR
2028 also needs to be defined.
2030 - CFG_FAULT_MII_ADDR:
2031 MII address of the PHY to check for the Ethernet link state.
2033 - CFG_64BIT_VSPRINTF:
2034 Makes vsprintf (and all *printf functions) support printing
2035 of 64bit values by using the L quantifier
2037 - CFG_64BIT_STRTOUL:
2038 Adds simple_strtoull that returns a 64bit value
2040 Low Level (hardware related) configuration options:
2041 ---------------------------------------------------
2043 - CFG_CACHELINE_SIZE:
2044 Cache Line Size of the CPU.
2047 Default address of the IMMR after system reset.
2049 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2050 and RPXsuper) to be able to adjust the position of
2051 the IMMR register after a reset.
2053 - Floppy Disk Support:
2054 CFG_FDC_DRIVE_NUMBER
2056 the default drive number (default value 0)
2060 defines the spacing between fdc chipset registers
2065 defines the offset of register from address. It
2066 depends on which part of the data bus is connected to
2067 the fdc chipset. (default value 0)
2069 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2070 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2073 if CFG_FDC_HW_INIT is defined, then the function
2074 fdc_hw_init() is called at the beginning of the FDC
2075 setup. fdc_hw_init() must be provided by the board
2076 source code. It is used to make hardware dependant
2079 - CFG_IMMR: Physical address of the Internal Memory.
2080 DO NOT CHANGE unless you know exactly what you're
2081 doing! (11-4) [MPC8xx/82xx systems only]
2083 - CFG_INIT_RAM_ADDR:
2085 Start address of memory area that can be used for
2086 initial data and stack; please note that this must be
2087 writable memory that is working WITHOUT special
2088 initialization, i. e. you CANNOT use normal RAM which
2089 will become available only after programming the
2090 memory controller and running certain initialization
2093 U-Boot uses the following memory types:
2094 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2095 - MPC824X: data cache
2096 - PPC4xx: data cache
2098 - CFG_GBL_DATA_OFFSET:
2100 Offset of the initial data structure in the memory
2101 area defined by CFG_INIT_RAM_ADDR. Usually
2102 CFG_GBL_DATA_OFFSET is chosen such that the initial
2103 data is located at the end of the available space
2104 (sometimes written as (CFG_INIT_RAM_END -
2105 CFG_INIT_DATA_SIZE), and the initial stack is just
2106 below that area (growing from (CFG_INIT_RAM_ADDR +
2107 CFG_GBL_DATA_OFFSET) downward.
2110 On the MPC824X (or other systems that use the data
2111 cache for initial memory) the address chosen for
2112 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2113 point to an otherwise UNUSED address space between
2114 the top of RAM and the start of the PCI space.
2116 - CFG_SIUMCR: SIU Module Configuration (11-6)
2118 - CFG_SYPCR: System Protection Control (11-9)
2120 - CFG_TBSCR: Time Base Status and Control (11-26)
2122 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2124 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2126 - CFG_SCCR: System Clock and reset Control Register (15-27)
2128 - CFG_OR_TIMING_SDRAM:
2132 periodic timer for refresh
2134 - CFG_DER: Debug Event Register (37-47)
2136 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2137 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2138 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2140 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2142 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2143 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2144 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2145 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2147 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2148 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2149 Machine Mode Register and Memory Periodic Timer
2150 Prescaler definitions (SDRAM timing)
2152 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2153 enable I2C microcode relocation patch (MPC8xx);
2154 define relocation offset in DPRAM [DSP2]
2156 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2157 enable SPI microcode relocation patch (MPC8xx);
2158 define relocation offset in DPRAM [SCC4]
2161 Use OSCM clock mode on MBX8xx board. Be careful,
2162 wrong setting might damage your board. Read
2163 doc/README.MBX before setting this variable!
2165 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2166 Offset of the bootmode word in DPRAM used by post
2167 (Power On Self Tests). This definition overrides
2168 #define'd default value in commproc.h resp.
2171 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2172 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2173 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2174 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2175 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2176 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2177 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2178 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2179 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2181 - CONFIG_ETHER_ON_FEC[12]
2182 Define to enable FEC[12] on a 8xx series processor.
2184 - CONFIG_FEC[12]_PHY
2185 Define to the hardcoded PHY address which corresponds
2186 to the given FEC; i. e.
2187 #define CONFIG_FEC1_PHY 4
2188 means that the PHY with address 4 is connected to FEC1
2190 When set to -1, means to probe for first available.
2192 - CONFIG_FEC[12]_PHY_NORXERR
2193 The PHY does not have a RXERR line (RMII only).
2194 (so program the FEC to ignore it).
2197 Enable RMII mode for all FECs.
2198 Note that this is a global option, we can't
2199 have one FEC in standard MII mode and another in RMII mode.
2201 - CONFIG_CRC32_VERIFY
2202 Add a verify option to the crc32 command.
2205 => crc32 -v <address> <count> <crc32>
2207 Where address/count indicate a memory area
2208 and crc32 is the correct crc32 which the
2212 Add the "loopw" memory command. This only takes effect if
2213 the memory commands are activated globally (CFG_CMD_MEM).
2216 Add the "mdc" and "mwc" memory commands. These are cyclic
2221 This command will print 4 bytes (10,11,12,13) each 500 ms.
2223 => mwc.l 100 12345678 10
2224 This command will write 12345678 to address 100 all 10 ms.
2226 This only takes effect if the memory commands are activated
2227 globally (CFG_CMD_MEM).
2229 - CONFIG_SKIP_LOWLEVEL_INIT
2230 - CONFIG_SKIP_RELOCATE_UBOOT
2232 [ARM only] If these variables are defined, then
2233 certain low level initializations (like setting up
2234 the memory controller) are omitted and/or U-Boot does
2235 not relocate itself into RAM.
2236 Normally these variables MUST NOT be defined. The
2237 only exception is when U-Boot is loaded (to RAM) by
2238 some other boot loader or by a debugger which
2239 performs these intializations itself.
2242 Building the Software:
2243 ======================
2245 Building U-Boot has been tested in native PPC environments (on a
2246 PowerBook G3 running LinuxPPC 2000) and in cross environments
2247 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2250 If you are not using a native PPC environment, it is assumed that you
2251 have the GNU cross compiling tools available in your path and named
2252 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2253 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2254 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2257 CROSS_COMPILE = ppc_4xx-
2260 U-Boot is intended to be simple to build. After installing the
2261 sources you must configure U-Boot for one specific board type. This
2266 where "NAME_config" is the name of one of the existing
2267 configurations; the following names are supported:
2269 ADCIOP_config FPS860L_config omap730p2_config
2270 ADS860_config GEN860T_config pcu_e_config
2272 AR405_config GENIETV_config PIP405_config
2273 at91rm9200dk_config GTH_config QS823_config
2274 CANBT_config hermes_config QS850_config
2275 cmi_mpc5xx_config hymod_config QS860T_config
2276 cogent_common_config IP860_config RPXlite_config
2277 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2278 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2279 CPCI405_config JSE_config rsdproto_config
2280 CPCIISER4_config LANTEC_config Sandpoint8240_config
2281 csb272_config lwmon_config sbc8260_config
2282 CU824_config MBX860T_config sbc8560_33_config
2283 DUET_ADS_config MBX_config sbc8560_66_config
2284 EBONY_config MPC8260ADS_config SM850_config
2285 ELPT860_config MPC8540ADS_config SPD823TS_config
2286 ESTEEM192E_config MPC8540EVAL_config stxgp3_config
2287 ETX094_config MPC8560ADS_config SXNI855T_config
2288 FADS823_config NETVIA_config TQM823L_config
2289 FADS850SAR_config omap1510inn_config TQM850L_config
2290 FADS860T_config omap1610h2_config TQM855L_config
2291 FPS850L_config omap1610inn_config TQM860L_config
2292 omap5912osk_config walnut_config
2293 omap2420h4_config Yukon8220_config
2296 Note: for some board special configuration names may exist; check if
2297 additional information is available from the board vendor; for
2298 instance, the TQM823L systems are available without (standard)
2299 or with LCD support. You can select such additional "features"
2300 when chosing the configuration, i. e.
2303 - will configure for a plain TQM823L, i. e. no LCD support
2305 make TQM823L_LCD_config
2306 - will configure for a TQM823L with U-Boot console on LCD
2311 Finally, type "make all", and you should get some working U-Boot
2312 images ready for download to / installation on your system:
2314 - "u-boot.bin" is a raw binary image
2315 - "u-boot" is an image in ELF binary format
2316 - "u-boot.srec" is in Motorola S-Record format
2319 Please be aware that the Makefiles assume you are using GNU make, so
2320 for instance on NetBSD you might need to use "gmake" instead of
2324 If the system board that you have is not listed, then you will need
2325 to port U-Boot to your hardware platform. To do this, follow these
2328 1. Add a new configuration option for your board to the toplevel
2329 "Makefile" and to the "MAKEALL" script, using the existing
2330 entries as examples. Note that here and at many other places
2331 boards and other names are listed in alphabetical sort order. Please
2333 2. Create a new directory to hold your board specific code. Add any
2334 files you need. In your board directory, you will need at least
2335 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2336 3. Create a new configuration file "include/configs/<board>.h" for
2338 3. If you're porting U-Boot to a new CPU, then also create a new
2339 directory to hold your CPU specific code. Add any files you need.
2340 4. Run "make <board>_config" with your new name.
2341 5. Type "make", and you should get a working "u-boot.srec" file
2342 to be installed on your target system.
2343 6. Debug and solve any problems that might arise.
2344 [Of course, this last step is much harder than it sounds.]
2347 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2348 ==============================================================
2350 If you have modified U-Boot sources (for instance added a new board
2351 or support for new devices, a new CPU, etc.) you are expected to
2352 provide feedback to the other developers. The feedback normally takes
2353 the form of a "patch", i. e. a context diff against a certain (latest
2354 official or latest in CVS) version of U-Boot sources.
2356 But before you submit such a patch, please verify that your modifi-
2357 cation did not break existing code. At least make sure that *ALL* of
2358 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2359 just run the "MAKEALL" script, which will configure and build U-Boot
2360 for ALL supported system. Be warned, this will take a while. You can
2361 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2362 environment variable to the script, i. e. to use the cross tools from
2363 MontaVista's Hard Hat Linux you can type
2365 CROSS_COMPILE=ppc_8xx- MAKEALL
2367 or to build on a native PowerPC system you can type
2369 CROSS_COMPILE=' ' MAKEALL
2371 See also "U-Boot Porting Guide" below.
2374 Monitor Commands - Overview:
2375 ============================
2377 go - start application at address 'addr'
2378 run - run commands in an environment variable
2379 bootm - boot application image from memory
2380 bootp - boot image via network using BootP/TFTP protocol
2381 tftpboot- boot image via network using TFTP protocol
2382 and env variables "ipaddr" and "serverip"
2383 (and eventually "gatewayip")
2384 rarpboot- boot image via network using RARP/TFTP protocol
2385 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2386 loads - load S-Record file over serial line
2387 loadb - load binary file over serial line (kermit mode)
2389 mm - memory modify (auto-incrementing)
2390 nm - memory modify (constant address)
2391 mw - memory write (fill)
2393 cmp - memory compare
2394 crc32 - checksum calculation
2395 imd - i2c memory display
2396 imm - i2c memory modify (auto-incrementing)
2397 inm - i2c memory modify (constant address)
2398 imw - i2c memory write (fill)
2399 icrc32 - i2c checksum calculation
2400 iprobe - probe to discover valid I2C chip addresses
2401 iloop - infinite loop on address range
2402 isdram - print SDRAM configuration information
2403 sspi - SPI utility commands
2404 base - print or set address offset
2405 printenv- print environment variables
2406 setenv - set environment variables
2407 saveenv - save environment variables to persistent storage
2408 protect - enable or disable FLASH write protection
2409 erase - erase FLASH memory
2410 flinfo - print FLASH memory information
2411 bdinfo - print Board Info structure
2412 iminfo - print header information for application image
2413 coninfo - print console devices and informations
2414 ide - IDE sub-system
2415 loop - infinite loop on address range
2416 loopw - infinite write loop on address range
2417 mtest - simple RAM test
2418 icache - enable or disable instruction cache
2419 dcache - enable or disable data cache
2420 reset - Perform RESET of the CPU
2421 echo - echo args to console
2422 version - print monitor version
2423 help - print online help
2424 ? - alias for 'help'
2427 Monitor Commands - Detailed Description:
2428 ========================================
2432 For now: just type "help <command>".
2435 Environment Variables:
2436 ======================
2438 U-Boot supports user configuration using Environment Variables which
2439 can be made persistent by saving to Flash memory.
2441 Environment Variables are set using "setenv", printed using
2442 "printenv", and saved to Flash using "saveenv". Using "setenv"
2443 without a value can be used to delete a variable from the
2444 environment. As long as you don't save the environment you are
2445 working with an in-memory copy. In case the Flash area containing the
2446 environment is erased by accident, a default environment is provided.
2448 Some configuration options can be set using Environment Variables:
2450 baudrate - see CONFIG_BAUDRATE
2452 bootdelay - see CONFIG_BOOTDELAY
2454 bootcmd - see CONFIG_BOOTCOMMAND
2456 bootargs - Boot arguments when booting an RTOS image
2458 bootfile - Name of the image to load with TFTP
2460 autoload - if set to "no" (any string beginning with 'n'),
2461 "bootp" will just load perform a lookup of the
2462 configuration from the BOOTP server, but not try to
2463 load any image using TFTP
2465 autostart - if set to "yes", an image loaded using the "bootp",
2466 "rarpboot", "tftpboot" or "diskboot" commands will
2467 be automatically started (by internally calling
2470 If set to "no", a standalone image passed to the
2471 "bootm" command will be copied to the load address
2472 (and eventually uncompressed), but NOT be started.
2473 This can be used to load and uncompress arbitrary
2476 i2cfast - (PPC405GP|PPC405EP only)
2477 if set to 'y' configures Linux I2C driver for fast
2478 mode (400kHZ). This environment variable is used in
2479 initialization code. So, for changes to be effective
2480 it must be saved and board must be reset.
2482 initrd_high - restrict positioning of initrd images:
2483 If this variable is not set, initrd images will be
2484 copied to the highest possible address in RAM; this
2485 is usually what you want since it allows for
2486 maximum initrd size. If for some reason you want to
2487 make sure that the initrd image is loaded below the
2488 CFG_BOOTMAPSZ limit, you can set this environment
2489 variable to a value of "no" or "off" or "0".
2490 Alternatively, you can set it to a maximum upper
2491 address to use (U-Boot will still check that it
2492 does not overwrite the U-Boot stack and data).
2494 For instance, when you have a system with 16 MB
2495 RAM, and want to reserve 4 MB from use by Linux,
2496 you can do this by adding "mem=12M" to the value of
2497 the "bootargs" variable. However, now you must make
2498 sure that the initrd image is placed in the first
2499 12 MB as well - this can be done with
2501 setenv initrd_high 00c00000
2503 If you set initrd_high to 0xFFFFFFFF, this is an
2504 indication to U-Boot that all addresses are legal
2505 for the Linux kernel, including addresses in flash
2506 memory. In this case U-Boot will NOT COPY the
2507 ramdisk at all. This may be useful to reduce the
2508 boot time on your system, but requires that this
2509 feature is supported by your Linux kernel.
2511 ipaddr - IP address; needed for tftpboot command
2513 loadaddr - Default load address for commands like "bootp",
2514 "rarpboot", "tftpboot", "loadb" or "diskboot"
2516 loads_echo - see CONFIG_LOADS_ECHO
2518 serverip - TFTP server IP address; needed for tftpboot command
2520 bootretry - see CONFIG_BOOT_RETRY_TIME
2522 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2524 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2526 ethprime - When CONFIG_NET_MULTI is enabled controls which
2527 interface is used first.
2529 ethact - When CONFIG_NET_MULTI is enabled controls which
2530 interface is currently active. For example you
2531 can do the following
2533 => setenv ethact FEC ETHERNET
2534 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2535 => setenv ethact SCC ETHERNET
2536 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2538 netretry - When set to "no" each network operation will
2539 either succeed or fail without retrying.
2540 When set to "once" the network operation will
2541 fail when all the available network interfaces
2542 are tried once without success.
2543 Useful on scripts which control the retry operation
2546 tftpsrcport - If this is set, the value is used for TFTP's
2549 tftpdstport - If this is set, the value is used for TFTP's UDP
2550 destination port instead of the Well Know Port 69.
2552 vlan - When set to a value < 4095 the traffic over
2553 ethernet is encapsulated/received over 802.1q
2556 The following environment variables may be used and automatically
2557 updated by the network boot commands ("bootp" and "rarpboot"),
2558 depending the information provided by your boot server:
2560 bootfile - see above
2561 dnsip - IP address of your Domain Name Server
2562 dnsip2 - IP address of your secondary Domain Name Server
2563 gatewayip - IP address of the Gateway (Router) to use
2564 hostname - Target hostname
2566 netmask - Subnet Mask
2567 rootpath - Pathname of the root filesystem on the NFS server
2568 serverip - see above
2571 There are two special Environment Variables:
2573 serial# - contains hardware identification information such
2574 as type string and/or serial number
2575 ethaddr - Ethernet address
2577 These variables can be set only once (usually during manufacturing of
2578 the board). U-Boot refuses to delete or overwrite these variables
2579 once they have been set once.
2582 Further special Environment Variables:
2584 ver - Contains the U-Boot version string as printed
2585 with the "version" command. This variable is
2586 readonly (see CONFIG_VERSION_VARIABLE).
2589 Please note that changes to some configuration parameters may take
2590 only effect after the next boot (yes, that's just like Windoze :-).
2593 Command Line Parsing:
2594 =====================
2596 There are two different command line parsers available with U-Boot:
2597 the old "simple" one, and the much more powerful "hush" shell:
2599 Old, simple command line parser:
2600 --------------------------------
2602 - supports environment variables (through setenv / saveenv commands)
2603 - several commands on one line, separated by ';'
2604 - variable substitution using "... ${name} ..." syntax
2605 - special characters ('$', ';') can be escaped by prefixing with '\',
2607 setenv bootcmd bootm \${address}
2608 - You can also escape text by enclosing in single apostrophes, for example:
2609 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2614 - similar to Bourne shell, with control structures like
2615 if...then...else...fi, for...do...done; while...do...done,
2616 until...do...done, ...
2617 - supports environment ("global") variables (through setenv / saveenv
2618 commands) and local shell variables (through standard shell syntax
2619 "name=value"); only environment variables can be used with "run"
2625 (1) If a command line (or an environment variable executed by a "run"
2626 command) contains several commands separated by semicolon, and
2627 one of these commands fails, then the remaining commands will be
2630 (2) If you execute several variables with one call to run (i. e.
2631 calling run with a list af variables as arguments), any failing
2632 command will cause "run" to terminate, i. e. the remaining
2633 variables are not executed.
2635 Note for Redundant Ethernet Interfaces:
2636 =======================================
2638 Some boards come with redundant ethernet interfaces; U-Boot supports
2639 such configurations and is capable of automatic selection of a
2640 "working" interface when needed. MAC assignment works as follows:
2642 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2643 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2644 "eth1addr" (=>eth1), "eth2addr", ...
2646 If the network interface stores some valid MAC address (for instance
2647 in SROM), this is used as default address if there is NO correspon-
2648 ding setting in the environment; if the corresponding environment
2649 variable is set, this overrides the settings in the card; that means:
2651 o If the SROM has a valid MAC address, and there is no address in the
2652 environment, the SROM's address is used.
2654 o If there is no valid address in the SROM, and a definition in the
2655 environment exists, then the value from the environment variable is
2658 o If both the SROM and the environment contain a MAC address, and
2659 both addresses are the same, this MAC address is used.
2661 o If both the SROM and the environment contain a MAC address, and the
2662 addresses differ, the value from the environment is used and a
2665 o If neither SROM nor the environment contain a MAC address, an error
2672 The "boot" commands of this monitor operate on "image" files which
2673 can be basicly anything, preceeded by a special header; see the
2674 definitions in include/image.h for details; basicly, the header
2675 defines the following image properties:
2677 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2678 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2679 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2680 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2681 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2682 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2683 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC).
2684 * Compression Type (uncompressed, gzip, bzip2)
2690 The header is marked by a special Magic Number, and both the header
2691 and the data portions of the image are secured against corruption by
2698 Although U-Boot should support any OS or standalone application
2699 easily, the main focus has always been on Linux during the design of
2702 U-Boot includes many features that so far have been part of some
2703 special "boot loader" code within the Linux kernel. Also, any
2704 "initrd" images to be used are no longer part of one big Linux image;
2705 instead, kernel and "initrd" are separate images. This implementation
2706 serves several purposes:
2708 - the same features can be used for other OS or standalone
2709 applications (for instance: using compressed images to reduce the
2710 Flash memory footprint)
2712 - it becomes much easier to port new Linux kernel versions because
2713 lots of low-level, hardware dependent stuff are done by U-Boot
2715 - the same Linux kernel image can now be used with different "initrd"
2716 images; of course this also means that different kernel images can
2717 be run with the same "initrd". This makes testing easier (you don't
2718 have to build a new "zImage.initrd" Linux image when you just
2719 change a file in your "initrd"). Also, a field-upgrade of the
2720 software is easier now.
2726 Porting Linux to U-Boot based systems:
2727 ---------------------------------------
2729 U-Boot cannot save you from doing all the necessary modifications to
2730 configure the Linux device drivers for use with your target hardware
2731 (no, we don't intend to provide a full virtual machine interface to
2734 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2736 Just make sure your machine specific header file (for instance
2737 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2738 Information structure as we define in include/u-boot.h, and make
2739 sure that your definition of IMAP_ADDR uses the same value as your
2740 U-Boot configuration in CFG_IMMR.
2743 Configuring the Linux kernel:
2744 -----------------------------
2746 No specific requirements for U-Boot. Make sure you have some root
2747 device (initial ramdisk, NFS) for your target system.
2750 Building a Linux Image:
2751 -----------------------
2753 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2754 not used. If you use recent kernel source, a new build target
2755 "uImage" will exist which automatically builds an image usable by
2756 U-Boot. Most older kernels also have support for a "pImage" target,
2757 which was introduced for our predecessor project PPCBoot and uses a
2758 100% compatible format.
2767 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2768 encapsulate a compressed Linux kernel image with header information,
2769 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2771 * build a standard "vmlinux" kernel image (in ELF binary format):
2773 * convert the kernel into a raw binary image:
2775 ${CROSS_COMPILE}-objcopy -O binary \
2776 -R .note -R .comment \
2777 -S vmlinux linux.bin
2779 * compress the binary image:
2783 * package compressed binary image for U-Boot:
2785 mkimage -A ppc -O linux -T kernel -C gzip \
2786 -a 0 -e 0 -n "Linux Kernel Image" \
2787 -d linux.bin.gz uImage
2790 The "mkimage" tool can also be used to create ramdisk images for use
2791 with U-Boot, either separated from the Linux kernel image, or
2792 combined into one file. "mkimage" encapsulates the images with a 64
2793 byte header containing information about target architecture,
2794 operating system, image type, compression method, entry points, time
2795 stamp, CRC32 checksums, etc.
2797 "mkimage" can be called in two ways: to verify existing images and
2798 print the header information, or to build new images.
2800 In the first form (with "-l" option) mkimage lists the information
2801 contained in the header of an existing U-Boot image; this includes
2802 checksum verification:
2804 tools/mkimage -l image
2805 -l ==> list image header information
2807 The second form (with "-d" option) is used to build a U-Boot image
2808 from a "data file" which is used as image payload:
2810 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2811 -n name -d data_file image
2812 -A ==> set architecture to 'arch'
2813 -O ==> set operating system to 'os'
2814 -T ==> set image type to 'type'
2815 -C ==> set compression type 'comp'
2816 -a ==> set load address to 'addr' (hex)
2817 -e ==> set entry point to 'ep' (hex)
2818 -n ==> set image name to 'name'
2819 -d ==> use image data from 'datafile'
2821 Right now, all Linux kernels for PowerPC systems use the same load
2822 address (0x00000000), but the entry point address depends on the
2825 - 2.2.x kernels have the entry point at 0x0000000C,
2826 - 2.3.x and later kernels have the entry point at 0x00000000.
2828 So a typical call to build a U-Boot image would read:
2830 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2831 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2832 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2833 > examples/uImage.TQM850L
2834 Image Name: 2.4.4 kernel for TQM850L
2835 Created: Wed Jul 19 02:34:59 2000
2836 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2837 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2838 Load Address: 0x00000000
2839 Entry Point: 0x00000000
2841 To verify the contents of the image (or check for corruption):
2843 -> tools/mkimage -l examples/uImage.TQM850L
2844 Image Name: 2.4.4 kernel for TQM850L
2845 Created: Wed Jul 19 02:34:59 2000
2846 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2847 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2848 Load Address: 0x00000000
2849 Entry Point: 0x00000000
2851 NOTE: for embedded systems where boot time is critical you can trade
2852 speed for memory and install an UNCOMPRESSED image instead: this
2853 needs more space in Flash, but boots much faster since it does not
2854 need to be uncompressed:
2856 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2857 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2858 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2859 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2860 > examples/uImage.TQM850L-uncompressed
2861 Image Name: 2.4.4 kernel for TQM850L
2862 Created: Wed Jul 19 02:34:59 2000
2863 Image Type: PowerPC Linux Kernel Image (uncompressed)
2864 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2865 Load Address: 0x00000000
2866 Entry Point: 0x00000000
2869 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2870 when your kernel is intended to use an initial ramdisk:
2872 -> tools/mkimage -n 'Simple Ramdisk Image' \
2873 > -A ppc -O linux -T ramdisk -C gzip \
2874 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2875 Image Name: Simple Ramdisk Image
2876 Created: Wed Jan 12 14:01:50 2000
2877 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2878 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2879 Load Address: 0x00000000
2880 Entry Point: 0x00000000
2883 Installing a Linux Image:
2884 -------------------------
2886 To downloading a U-Boot image over the serial (console) interface,
2887 you must convert the image to S-Record format:
2889 objcopy -I binary -O srec examples/image examples/image.srec
2891 The 'objcopy' does not understand the information in the U-Boot
2892 image header, so the resulting S-Record file will be relative to
2893 address 0x00000000. To load it to a given address, you need to
2894 specify the target address as 'offset' parameter with the 'loads'
2897 Example: install the image to address 0x40100000 (which on the
2898 TQM8xxL is in the first Flash bank):
2900 => erase 40100000 401FFFFF
2906 ## Ready for S-Record download ...
2907 ~>examples/image.srec
2908 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2910 15989 15990 15991 15992
2911 [file transfer complete]
2913 ## Start Addr = 0x00000000
2916 You can check the success of the download using the 'iminfo' command;
2917 this includes a checksum verification so you can be sure no data
2918 corruption happened:
2922 ## Checking Image at 40100000 ...
2923 Image Name: 2.2.13 for initrd on TQM850L
2924 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2925 Data Size: 335725 Bytes = 327 kB = 0 MB
2926 Load Address: 00000000
2927 Entry Point: 0000000c
2928 Verifying Checksum ... OK
2934 The "bootm" command is used to boot an application that is stored in
2935 memory (RAM or Flash). In case of a Linux kernel image, the contents
2936 of the "bootargs" environment variable is passed to the kernel as
2937 parameters. You can check and modify this variable using the
2938 "printenv" and "setenv" commands:
2941 => printenv bootargs
2942 bootargs=root=/dev/ram
2944 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2946 => printenv bootargs
2947 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2950 ## Booting Linux kernel at 40020000 ...
2951 Image Name: 2.2.13 for NFS on TQM850L
2952 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2953 Data Size: 381681 Bytes = 372 kB = 0 MB
2954 Load Address: 00000000
2955 Entry Point: 0000000c
2956 Verifying Checksum ... OK
2957 Uncompressing Kernel Image ... OK
2958 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
2959 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2960 time_init: decrementer frequency = 187500000/60
2961 Calibrating delay loop... 49.77 BogoMIPS
2962 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2965 If you want to boot a Linux kernel with initial ram disk, you pass
2966 the memory addresses of both the kernel and the initrd image (PPBCOOT
2967 format!) to the "bootm" command:
2969 => imi 40100000 40200000
2971 ## Checking Image at 40100000 ...
2972 Image Name: 2.2.13 for initrd on TQM850L
2973 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2974 Data Size: 335725 Bytes = 327 kB = 0 MB
2975 Load Address: 00000000
2976 Entry Point: 0000000c
2977 Verifying Checksum ... OK
2979 ## Checking Image at 40200000 ...
2980 Image Name: Simple Ramdisk Image
2981 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2982 Data Size: 566530 Bytes = 553 kB = 0 MB
2983 Load Address: 00000000
2984 Entry Point: 00000000
2985 Verifying Checksum ... OK
2987 => bootm 40100000 40200000
2988 ## Booting Linux kernel at 40100000 ...
2989 Image Name: 2.2.13 for initrd on TQM850L
2990 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2991 Data Size: 335725 Bytes = 327 kB = 0 MB
2992 Load Address: 00000000
2993 Entry Point: 0000000c
2994 Verifying Checksum ... OK
2995 Uncompressing Kernel Image ... OK
2996 ## Loading RAMDisk Image at 40200000 ...
2997 Image Name: Simple Ramdisk Image
2998 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2999 Data Size: 566530 Bytes = 553 kB = 0 MB
3000 Load Address: 00000000
3001 Entry Point: 00000000
3002 Verifying Checksum ... OK
3003 Loading Ramdisk ... OK
3004 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
3005 Boot arguments: root=/dev/ram
3006 time_init: decrementer frequency = 187500000/60
3007 Calibrating delay loop... 49.77 BogoMIPS
3009 RAMDISK: Compressed image found at block 0
3010 VFS: Mounted root (ext2 filesystem).
3014 More About U-Boot Image Types:
3015 ------------------------------
3017 U-Boot supports the following image types:
3019 "Standalone Programs" are directly runnable in the environment
3020 provided by U-Boot; it is expected that (if they behave
3021 well) you can continue to work in U-Boot after return from
3022 the Standalone Program.
3023 "OS Kernel Images" are usually images of some Embedded OS which
3024 will take over control completely. Usually these programs
3025 will install their own set of exception handlers, device
3026 drivers, set up the MMU, etc. - this means, that you cannot
3027 expect to re-enter U-Boot except by resetting the CPU.
3028 "RAMDisk Images" are more or less just data blocks, and their
3029 parameters (address, size) are passed to an OS kernel that is
3031 "Multi-File Images" contain several images, typically an OS
3032 (Linux) kernel image and one or more data images like
3033 RAMDisks. This construct is useful for instance when you want
3034 to boot over the network using BOOTP etc., where the boot
3035 server provides just a single image file, but you want to get
3036 for instance an OS kernel and a RAMDisk image.
3038 "Multi-File Images" start with a list of image sizes, each
3039 image size (in bytes) specified by an "uint32_t" in network
3040 byte order. This list is terminated by an "(uint32_t)0".
3041 Immediately after the terminating 0 follow the images, one by
3042 one, all aligned on "uint32_t" boundaries (size rounded up to
3043 a multiple of 4 bytes).
3045 "Firmware Images" are binary images containing firmware (like
3046 U-Boot or FPGA images) which usually will be programmed to
3049 "Script files" are command sequences that will be executed by
3050 U-Boot's command interpreter; this feature is especially
3051 useful when you configure U-Boot to use a real shell (hush)
3052 as command interpreter.
3058 One of the features of U-Boot is that you can dynamically load and
3059 run "standalone" applications, which can use some resources of
3060 U-Boot like console I/O functions or interrupt services.
3062 Two simple examples are included with the sources:
3067 'examples/hello_world.c' contains a small "Hello World" Demo
3068 application; it is automatically compiled when you build U-Boot.
3069 It's configured to run at address 0x00040004, so you can play with it
3073 ## Ready for S-Record download ...
3074 ~>examples/hello_world.srec
3075 1 2 3 4 5 6 7 8 9 10 11 ...
3076 [file transfer complete]
3078 ## Start Addr = 0x00040004
3080 => go 40004 Hello World! This is a test.
3081 ## Starting application at 0x00040004 ...
3092 Hit any key to exit ...
3094 ## Application terminated, rc = 0x0
3096 Another example, which demonstrates how to register a CPM interrupt
3097 handler with the U-Boot code, can be found in 'examples/timer.c'.
3098 Here, a CPM timer is set up to generate an interrupt every second.
3099 The interrupt service routine is trivial, just printing a '.'
3100 character, but this is just a demo program. The application can be
3101 controlled by the following keys:
3103 ? - print current values og the CPM Timer registers
3104 b - enable interrupts and start timer
3105 e - stop timer and disable interrupts
3106 q - quit application
3109 ## Ready for S-Record download ...
3110 ~>examples/timer.srec
3111 1 2 3 4 5 6 7 8 9 10 11 ...
3112 [file transfer complete]
3114 ## Start Addr = 0x00040004
3117 ## Starting application at 0x00040004 ...
3120 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3123 [q, b, e, ?] Set interval 1000000 us
3126 [q, b, e, ?] ........
3127 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3130 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3133 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3136 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3138 [q, b, e, ?] ...Stopping timer
3140 [q, b, e, ?] ## Application terminated, rc = 0x0
3146 Over time, many people have reported problems when trying to use the
3147 "minicom" terminal emulation program for serial download. I (wd)
3148 consider minicom to be broken, and recommend not to use it. Under
3149 Unix, I recommend to use C-Kermit for general purpose use (and
3150 especially for kermit binary protocol download ("loadb" command), and
3151 use "cu" for S-Record download ("loads" command).
3153 Nevertheless, if you absolutely want to use it try adding this
3154 configuration to your "File transfer protocols" section:
3156 Name Program Name U/D FullScr IO-Red. Multi
3157 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3158 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3164 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3165 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3167 Building requires a cross environment; it is known to work on
3168 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3169 need gmake since the Makefiles are not compatible with BSD make).
3170 Note that the cross-powerpc package does not install include files;
3171 attempting to build U-Boot will fail because <machine/ansi.h> is
3172 missing. This file has to be installed and patched manually:
3174 # cd /usr/pkg/cross/powerpc-netbsd/include
3176 # ln -s powerpc machine
3177 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3178 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3180 Native builds *don't* work due to incompatibilities between native
3181 and U-Boot include files.
3183 Booting assumes that (the first part of) the image booted is a
3184 stage-2 loader which in turn loads and then invokes the kernel
3185 proper. Loader sources will eventually appear in the NetBSD source
3186 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3187 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3190 Implementation Internals:
3191 =========================
3193 The following is not intended to be a complete description of every
3194 implementation detail. However, it should help to understand the
3195 inner workings of U-Boot and make it easier to port it to custom
3199 Initial Stack, Global Data:
3200 ---------------------------
3202 The implementation of U-Boot is complicated by the fact that U-Boot
3203 starts running out of ROM (flash memory), usually without access to
3204 system RAM (because the memory controller is not initialized yet).
3205 This means that we don't have writable Data or BSS segments, and BSS
3206 is not initialized as zero. To be able to get a C environment working
3207 at all, we have to allocate at least a minimal stack. Implementation
3208 options for this are defined and restricted by the CPU used: Some CPU
3209 models provide on-chip memory (like the IMMR area on MPC8xx and
3210 MPC826x processors), on others (parts of) the data cache can be
3211 locked as (mis-) used as memory, etc.
3213 Chris Hallinan posted a good summary of these issues to the
3214 u-boot-users mailing list:
3216 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3217 From: "Chris Hallinan" <clh@net1plus.com>
3218 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3221 Correct me if I'm wrong, folks, but the way I understand it
3222 is this: Using DCACHE as initial RAM for Stack, etc, does not
3223 require any physical RAM backing up the cache. The cleverness
3224 is that the cache is being used as a temporary supply of
3225 necessary storage before the SDRAM controller is setup. It's
3226 beyond the scope of this list to expain the details, but you
3227 can see how this works by studying the cache architecture and
3228 operation in the architecture and processor-specific manuals.
3230 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3231 is another option for the system designer to use as an
3232 initial stack/ram area prior to SDRAM being available. Either
3233 option should work for you. Using CS 4 should be fine if your
3234 board designers haven't used it for something that would
3235 cause you grief during the initial boot! It is frequently not
3238 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3239 with your processor/board/system design. The default value
3240 you will find in any recent u-boot distribution in
3241 walnut.h should work for you. I'd set it to a value larger
3242 than your SDRAM module. If you have a 64MB SDRAM module, set
3243 it above 400_0000. Just make sure your board has no resources
3244 that are supposed to respond to that address! That code in
3245 start.S has been around a while and should work as is when
3246 you get the config right.
3251 It is essential to remember this, since it has some impact on the C
3252 code for the initialization procedures:
3254 * Initialized global data (data segment) is read-only. Do not attempt
3257 * Do not use any unitialized global data (or implicitely initialized
3258 as zero data - BSS segment) at all - this is undefined, initiali-
3259 zation is performed later (when relocating to RAM).
3261 * Stack space is very limited. Avoid big data buffers or things like
3264 Having only the stack as writable memory limits means we cannot use
3265 normal global data to share information beween the code. But it
3266 turned out that the implementation of U-Boot can be greatly
3267 simplified by making a global data structure (gd_t) available to all
3268 functions. We could pass a pointer to this data as argument to _all_
3269 functions, but this would bloat the code. Instead we use a feature of
3270 the GCC compiler (Global Register Variables) to share the data: we
3271 place a pointer (gd) to the global data into a register which we
3272 reserve for this purpose.
3274 When choosing a register for such a purpose we are restricted by the
3275 relevant (E)ABI specifications for the current architecture, and by
3276 GCC's implementation.
3278 For PowerPC, the following registers have specific use:
3281 R3-R4: parameter passing and return values
3282 R5-R10: parameter passing
3283 R13: small data area pointer
3287 (U-Boot also uses R14 as internal GOT pointer.)
3289 ==> U-Boot will use R29 to hold a pointer to the global data
3291 Note: on PPC, we could use a static initializer (since the
3292 address of the global data structure is known at compile time),
3293 but it turned out that reserving a register results in somewhat
3294 smaller code - although the code savings are not that big (on
3295 average for all boards 752 bytes for the whole U-Boot image,
3296 624 text + 127 data).
3298 On ARM, the following registers are used:
3300 R0: function argument word/integer result
3301 R1-R3: function argument word
3303 R10: stack limit (used only if stack checking if enabled)
3304 R11: argument (frame) pointer
3305 R12: temporary workspace
3308 R15: program counter
3310 ==> U-Boot will use R8 to hold a pointer to the global data
3312 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3313 or current versions of GCC may "optimize" the code too much.
3318 U-Boot runs in system state and uses physical addresses, i.e. the
3319 MMU is not used either for address mapping nor for memory protection.
3321 The available memory is mapped to fixed addresses using the memory
3322 controller. In this process, a contiguous block is formed for each
3323 memory type (Flash, SDRAM, SRAM), even when it consists of several
3324 physical memory banks.
3326 U-Boot is installed in the first 128 kB of the first Flash bank (on
3327 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3328 booting and sizing and initializing DRAM, the code relocates itself
3329 to the upper end of DRAM. Immediately below the U-Boot code some
3330 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3331 configuration setting]. Below that, a structure with global Board
3332 Info data is placed, followed by the stack (growing downward).
3334 Additionally, some exception handler code is copied to the low 8 kB
3335 of DRAM (0x00000000 ... 0x00001FFF).
3337 So a typical memory configuration with 16 MB of DRAM could look like
3340 0x0000 0000 Exception Vector code
3343 0x0000 2000 Free for Application Use
3349 0x00FB FF20 Monitor Stack (Growing downward)
3350 0x00FB FFAC Board Info Data and permanent copy of global data
3351 0x00FC 0000 Malloc Arena
3354 0x00FE 0000 RAM Copy of Monitor Code
3355 ... eventually: LCD or video framebuffer
3356 ... eventually: pRAM (Protected RAM - unchanged by reset)
3357 0x00FF FFFF [End of RAM]
3360 System Initialization:
3361 ----------------------
3363 In the reset configuration, U-Boot starts at the reset entry point
3364 (on most PowerPC systens at address 0x00000100). Because of the reset
3365 configuration for CS0# this is a mirror of the onboard Flash memory.
3366 To be able to re-map memory U-Boot then jumps to its link address.
3367 To be able to implement the initialization code in C, a (small!)
3368 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3369 which provide such a feature like MPC8xx or MPC8260), or in a locked
3370 part of the data cache. After that, U-Boot initializes the CPU core,
3371 the caches and the SIU.
3373 Next, all (potentially) available memory banks are mapped using a
3374 preliminary mapping. For example, we put them on 512 MB boundaries
3375 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3376 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3377 programmed for SDRAM access. Using the temporary configuration, a
3378 simple memory test is run that determines the size of the SDRAM
3381 When there is more than one SDRAM bank, and the banks are of
3382 different size, the largest is mapped first. For equal size, the first
3383 bank (CS2#) is mapped first. The first mapping is always for address
3384 0x00000000, with any additional banks following immediately to create
3385 contiguous memory starting from 0.
3387 Then, the monitor installs itself at the upper end of the SDRAM area
3388 and allocates memory for use by malloc() and for the global Board
3389 Info data; also, the exception vector code is copied to the low RAM
3390 pages, and the final stack is set up.
3392 Only after this relocation will you have a "normal" C environment;
3393 until that you are restricted in several ways, mostly because you are
3394 running from ROM, and because the code will have to be relocated to a
3398 U-Boot Porting Guide:
3399 ----------------------
3401 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3405 int main (int argc, char *argv[])
3407 sighandler_t no_more_time;
3409 signal (SIGALRM, no_more_time);
3410 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3412 if (available_money > available_manpower) {
3413 pay consultant to port U-Boot;
3417 Download latest U-Boot source;
3419 Subscribe to u-boot-users mailing list;
3422 email ("Hi, I am new to U-Boot, how do I get started?");
3426 Read the README file in the top level directory;
3427 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3428 Read the source, Luke;
3431 if (available_money > toLocalCurrency ($2500)) {
3434 Add a lot of aggravation and time;
3437 Create your own board support subdirectory;
3439 Create your own board config file;
3443 Add / modify source code;
3447 email ("Hi, I am having problems...");
3449 Send patch file to Wolfgang;
3454 void no_more_time (int sig)
3463 All contributions to U-Boot should conform to the Linux kernel
3464 coding style; see the file "Documentation/CodingStyle" in your Linux
3465 kernel source directory.
3467 Please note that U-Boot is implemented in C (and to some small parts
3468 in Assembler); no C++ is used, so please do not use C++ style
3469 comments (//) in your code.
3471 Please also stick to the following formatting rules:
3472 - remove any trailing white space
3473 - use TAB characters for indentation, not spaces
3474 - make sure NOT to use DOS '\r\n' line feeds
3475 - do not add more than 2 empty lines to source files
3476 - do not add trailing empty lines to source files
3478 Submissions which do not conform to the standards may be returned
3479 with a request to reformat the changes.
3485 Since the number of patches for U-Boot is growing, we need to
3486 establish some rules. Submissions which do not conform to these rules
3487 may be rejected, even when they contain important and valuable stuff.
3489 Patches shall be sent to the u-boot-users mailing list.
3491 When you send a patch, please include the following information with
3494 * For bug fixes: a description of the bug and how your patch fixes
3495 this bug. Please try to include a way of demonstrating that the
3496 patch actually fixes something.
3498 * For new features: a description of the feature and your
3501 * A CHANGELOG entry as plaintext (separate from the patch)
3503 * For major contributions, your entry to the CREDITS file
3505 * When you add support for a new board, don't forget to add this
3506 board to the MAKEALL script, too.
3508 * If your patch adds new configuration options, don't forget to
3509 document these in the README file.
3511 * The patch itself. If you are accessing the CVS repository use "cvs
3512 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3513 version of diff does not support these options, then get the latest
3514 version of GNU diff.
3516 The current directory when running this command shall be the top
3517 level directory of the U-Boot source tree, or it's parent directory
3518 (i. e. please make sure that your patch includes sufficient
3519 directory information for the affected files).
3521 We accept patches as plain text, MIME attachments or as uuencoded
3524 * If one logical set of modifications affects or creates several
3525 files, all these changes shall be submitted in a SINGLE patch file.
3527 * Changesets that contain different, unrelated modifications shall be
3528 submitted as SEPARATE patches, one patch per changeset.
3533 * Before sending the patch, run the MAKEALL script on your patched
3534 source tree and make sure that no errors or warnings are reported
3535 for any of the boards.
3537 * Keep your modifications to the necessary minimum: A patch
3538 containing several unrelated changes or arbitrary reformats will be
3539 returned with a request to re-formatting / split it.
3541 * If you modify existing code, make sure that your new code does not
3542 add to the memory footprint of the code ;-) Small is beautiful!
3543 When adding new features, these should compile conditionally only
3544 (using #ifdef), and the resulting code with the new feature
3545 disabled must not need more memory than the old code without your
3548 * Remember that there is a size limit of 40 kB per message on the
3549 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob