2 # (C) Copyright 2000 - 2002
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 and ARM processors, which can be
29 installed in a boot ROM and used to initialize and test the hardware
30 or to download and run application code.
32 The development of U-Boot is closely related to Linux: some parts of
33 the source code originate in the Linux source tree, we have some
34 header files in common, and special provision has been made to
35 support booting of Linux images.
37 Some attention has been paid to make this software easily
38 configurable and extendable. For instance, all monitor commands are
39 implemented with the same call interface, so that it's very easy to
40 add new commands. Also, instead of permanently adding rarely used
41 code (for instance hardware test utilities) to the monitor, you can
42 load and run it dynamically.
48 In general, all boards for which a configuration option exists in the
49 Makefile have been tested to some extent and can be considered
50 "working". In fact, many of them are used in production systems.
52 In case of problems see the CHANGELOG and CREDITS files to find out
53 who contributed the specific port.
59 In case you have questions about, problems with or contributions for
60 U-Boot you should send a message to the U-Boot mailing list at
61 <u-boot-users@lists.sourceforge.net>. There is also an archive of
62 previous traffic on the mailing list - please search the archive
63 before asking FAQ's. Please see
64 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
70 - start from 8xxrom sources
71 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
73 - make it easier to add custom boards
74 - make it possible to add other [PowerPC] CPUs
75 - extend functions, especially:
76 * Provide extended interface to Linux boot loader
79 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
80 - create ARMBoot project (http://sourceforge.net/projects/armboot)
81 - add other CPU families (starting with ARM)
82 - create U-Boot project (http://sourceforge.net/projects/u-boot)
88 The "official" name of this project is "Das U-Boot". The spelling
89 "U-Boot" shall be used in all written text (documentation, comments
90 in source files etc.). Example:
92 This is the README file for the U-Boot project.
94 File names etc. shall be based on the string "u-boot". Examples:
96 include/asm-ppc/u-boot.h
98 #include <asm/u-boot.h>
100 Variable names, preprocessor constants etc. shall be either based on
101 the string "u_boot" or on "U_BOOT". Example:
103 U_BOOT_VERSION u_boot_logo
104 IH_OS_U_BOOT u_boot_hush_start
110 U-Boot uses a 3 level version number containing a version, a
111 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
112 sub-version "34", and patchlevel "4".
114 The patchlevel is used to indicate certain stages of development
115 between released versions, i. e. officially released versions of
116 U-Boot will always have a patchlevel of "0".
122 - board Board dependend files
123 - common Misc architecture independend functions
124 - cpu CPU specific files
125 - disk Code for disk drive partition handling
126 - doc Documentation (don't expect too much)
127 - drivers Common used device drivers
128 - dtt Digital Thermometer and Thermostat drivers
129 - examples Example code for standalone applications, etc.
130 - include Header Files
131 - disk Harddisk interface code
132 - net Networking code
133 - ppc Files generic to PowerPC architecture
134 - post Power On Self Test
135 - post/arch Symlink to architecture specific Power On Self Test
136 - post/arch-ppc PowerPC architecture specific Power On Self Test
137 - post/cpu/mpc8260 MPC8260 CPU specific Power On Self Test
138 - post/cpu/mpc8xx MPC8xx CPU specific Power On Self Test
139 - rtc Real Time Clock drivers
140 - tools Tools to build S-Record or U-Boot images, etc.
142 - cpu/74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
143 - cpu/mpc5xx Files specific to Motorola MPC5xx CPUs
144 - cpu/mpc8xx Files specific to Motorola MPC8xx CPUs
145 - cpu/mpc824x Files specific to Motorola MPC824x CPUs
146 - cpu/mpc8260 Files specific to Motorola MPC8260 CPU
147 - cpu/ppc4xx Files specific to IBM 4xx CPUs
149 - board/LEOX/ Files specific to boards manufactured by The LEOX team
150 - board/LEOX/elpt860 Files specific to ELPT860 boards
152 Files specific to RPXClassic boards
153 - board/RPXlite Files specific to RPXlite boards
154 - board/c2mon Files specific to c2mon boards
155 - board/cmi Files specific to cmi boards
156 - board/cogent Files specific to Cogent boards
157 (need further configuration)
158 Files specific to CPCIISER4 boards
159 - board/cpu86 Files specific to CPU86 boards
160 - board/cray/ Files specific to boards manufactured by Cray
161 - board/cray/L1 Files specific to L1 boards
162 - board/cu824 Files specific to CU824 boards
163 - board/ebony Files specific to IBM Ebony board
164 - board/eric Files specific to ERIC boards
165 - board/esd/ Files specific to boards manufactured by ESD
166 - board/esd/adciop Files specific to ADCIOP boards
167 - board/esd/ar405 Files specific to AR405 boards
168 - board/esd/canbt Files specific to CANBT boards
169 - board/esd/cpci405 Files specific to CPCI405 boards
170 - board/esd/cpciiser4 Files specific to CPCIISER4 boards
171 - board/esd/common Common files for ESD boards
172 - board/esd/dasa_sim Files specific to DASA_SIM boards
173 - board/esd/du405 Files specific to DU405 boards
174 - board/esd/ocrtc Files specific to OCRTC boards
175 - board/esd/pci405 Files specific to PCI405 boards
177 Files specific to ESTEEM192E boards
178 - board/etx094 Files specific to ETX_094 boards
180 Files specific to EVB64260 boards
181 - board/fads Files specific to FADS boards
182 - board/flagadm Files specific to FLAGADM boards
183 - board/gen860t Files specific to GEN860T and GEN860T_SC boards
184 - board/genietv Files specific to GENIETV boards
185 - board/gth Files specific to GTH boards
186 - board/hermes Files specific to HERMES boards
187 - board/hymod Files specific to HYMOD boards
188 - board/icu862 Files specific to ICU862 boards
189 - board/ip860 Files specific to IP860 boards
191 Files specific to Interphase4539 boards
192 - board/ivm Files specific to IVMS8/IVML24 boards
193 - board/lantec Files specific to LANTEC boards
194 - board/lwmon Files specific to LWMON boards
195 - board/mbx8xx Files specific to MBX boards
197 Files specific to MMPC8260ADS boards
198 - board/mpl/ Files specific to boards manufactured by MPL
199 - board/mpl/common Common files for MPL boards
200 - board/mpl/pip405 Files specific to PIP405 boards
201 - board/mpl/mip405 Files specific to MIP405 boards
202 - board/musenki Files specific to MUSEKNI boards
203 - board/mvs1 Files specific to MVS1 boards
204 - board/nx823 Files specific to NX823 boards
205 - board/oxc Files specific to OXC boards
206 - board/pcippc2 Files specific to PCIPPC2/PCIPPC6 boards
207 - board/pm826 Files specific to PM826 boards
209 Files specific to PPMC8260 boards
211 Files specific to RPXsuper boards
213 Files specific to RSDproto boards
215 Files specific to Sandpoint boards
216 - board/sbc8260 Files specific to SBC8260 boards
217 - board/sacsng Files specific to SACSng boards
218 - board/siemens Files specific to boards manufactured by Siemens AG
219 - board/siemens/CCM Files specific to CCM boards
220 - board/siemens/IAD210 Files specific to IAD210 boards
221 - board/siemens/SCM Files specific to SCM boards
222 - board/siemens/pcu_e Files specific to PCU_E boards
223 - board/sixnet Files specific to SIXNET boards
224 - board/spd8xx Files specific to SPD8xxTS boards
225 - board/tqm8260 Files specific to TQM8260 boards
226 - board/tqm8xx Files specific to TQM8xxL boards
227 - board/w7o Files specific to W7O boards
229 Files specific to Walnut405 boards
230 - board/westel/ Files specific to boards manufactured by Westel Wireless
231 - board/westel/amx860 Files specific to AMX860 boards
232 - board/utx8245 Files specific to UTX8245 boards
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the cpu type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one of
296 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
298 or CONFIG_MPC824X, CONFIG_MPC8260
311 - Board Type: Define exactly one of
313 PowerPC based boards:
314 ---------------------
316 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
317 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
318 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
319 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
320 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
321 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
322 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
323 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
324 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
325 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
326 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
327 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
328 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
329 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
330 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
331 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
332 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
333 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
334 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
335 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
336 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
337 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
338 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
339 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
340 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
341 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
342 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
343 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
344 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
345 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
346 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI
351 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
352 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
353 CONFIG_SHANNON, CONFIG_SMDK2400, CONFIG_SMDK2410,
357 - CPU Module Type: (if CONFIG_COGENT is defined)
358 Define exactly one of
360 --- FIXME --- not tested yet:
361 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
362 CONFIG_CMA287_23, CONFIG_CMA287_50
364 - Motherboard Type: (if CONFIG_COGENT is defined)
365 Define exactly one of
366 CONFIG_CMA101, CONFIG_CMA102
368 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
369 Define one or more of
372 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
373 Define one or more of
374 CONFIG_LCD_HEARTBEAT - update a character position on
375 the lcd display every second with
378 - MPC824X Family Member (if CONFIG_MPC824X is defined)
379 Define exactly one of
380 CONFIG_MPC8240, CONFIG_MPC8245
382 - 8xx CPU Options: (if using an 8xx cpu)
383 Define one or more of
384 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() can not work e.g.
385 no 32KHz reference PIT/RTC clock
390 U-Boot stores all clock information in Hz
391 internally. For binary compatibility with older Linux
392 kernels (which expect the clocks passed in the
393 bd_info data to be in MHz) the environment variable
394 "clocks_in_mhz" can be defined so that U-Boot
395 converts clock data to MHZ before passing it to the
398 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
399 "clocks_in_mhz=1" is automatically included in the
403 Depending on board, define exactly one serial port
404 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
405 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
406 console by defining CONFIG_8xx_CONS_NONE
408 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
409 port routines must be defined elsewhere
410 (i.e. serial_init(), serial_getc(), ...)
413 Enables console device for a color framebuffer. Needs following
414 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
415 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
417 VIDEO_HW_RECTFILL graphic chip supports
420 VIDEO_HW_BITBLT graphic chip supports
421 bit-blit (cf. smiLynxEM)
422 VIDEO_VISIBLE_COLS visible pixel columns
424 VIDEO_VISIBLE_ROWS visible pixel rows
425 VIDEO_PIXEL_SIZE bytes per pixel
426 VIDEO_DATA_FORMAT graphic data format
427 (0-5, cf. cfb_console.c)
428 VIDEO_FB_ADRS framebuffer address
429 VIDEO_KBD_INIT_FCT keyboard int fct
430 (i.e. i8042_kbd_init())
431 VIDEO_TSTC_FCT test char fct
433 VIDEO_GETC_FCT get char fct
435 CONFIG_CONSOLE_CURSOR cursor drawing on/off
436 (requires blink timer
438 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
439 CONFIG_CONSOLE_TIME display time/date info in
441 (requires CFG_CMD_DATE)
442 CONFIG_VIDEO_LOGO display Linux logo in
444 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
445 linux_logo.h for logo.
446 Requires CONFIG_VIDEO_LOGO
447 CONFIG_CONSOLE_EXTRA_INFO
448 addional board info beside
451 When CONFIG_CFB_CONSOLE is defined, video console is
452 default i/o. Serial console can be forced with
453 environment 'console=serial'.
456 CONFIG_BAUDRATE - in bps
457 Select one of the baudrates listed in
458 CFG_BAUDRATE_TABLE, see below.
460 - Interrupt driven serial port input:
461 CONFIG_SERIAL_SOFTWARE_FIFO
464 Use an interrupt handler for receiving data on the
465 serial port. It also enables using hardware handshake
466 (RTS/CTS) and UART's built-in FIFO. Set the number of
467 bytes the interrupt driven input buffer should have.
469 Set to 0 to disable this feature (this is the default).
470 This will also disable hardware handshake.
472 - Boot Delay: CONFIG_BOOTDELAY - in seconds
473 Delay before automatically booting the default image;
474 set to -1 to disable autoboot.
476 See doc/README.autoboot for these options that
477 work with CONFIG_BOOTDELAY. None are required.
478 CONFIG_BOOT_RETRY_TIME
479 CONFIG_BOOT_RETRY_MIN
480 CONFIG_AUTOBOOT_KEYED
481 CONFIG_AUTOBOOT_PROMPT
482 CONFIG_AUTOBOOT_DELAY_STR
483 CONFIG_AUTOBOOT_STOP_STR
484 CONFIG_AUTOBOOT_DELAY_STR2
485 CONFIG_AUTOBOOT_STOP_STR2
486 CONFIG_ZERO_BOOTDELAY_CHECK
487 CONFIG_RESET_TO_RETRY
491 Only needed when CONFIG_BOOTDELAY is enabled;
492 define a command string that is automatically executed
493 when no character is read on the console interface
494 within "Boot Delay" after reset.
497 This can be used to pass arguments to the bootm
498 command. The value of CONFIG_BOOTARGS goes into the
499 environment value "bootargs".
501 CONFIG_RAMBOOT and CONFIG_NFSBOOT
502 The value of these goes into the environment as
503 "ramboot" and "nfsboot" respectively, and can be used
504 as a convenience, when switching between booting from
510 When this option is #defined, the existence of the
511 environment variable "preboot" will be checked
512 immediately before starting the CONFIG_BOOTDELAY
513 countdown and/or running the auto-boot command resp.
514 entering interactive mode.
516 This feature is especially useful when "preboot" is
517 automatically generated or modified. For an example
518 see the LWMON board specific code: here "preboot" is
519 modified when the user holds down a certain
520 combination of keys on the (special) keyboard when
523 - Serial Download Echo Mode:
525 If defined to 1, all characters received during a
526 serial download (using the "loads" command) are
527 echoed back. This might be needed by some terminal
528 emulations (like "cu"), but may as well just take
529 time on others. This setting #define's the initial
530 value of the "loads_echo" environment variable.
532 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
534 Select one of the baudrates listed in
535 CFG_BAUDRATE_TABLE, see below.
539 Most monitor functions can be selected (or
540 de-selected) by adjusting the definition of
541 CONFIG_COMMANDS; to select individual functions,
542 #define CONFIG_COMMANDS by "OR"ing any of the
545 #define enables commands:
546 -------------------------
547 CFG_CMD_ASKENV * ask for env variable
549 CFG_CMD_BEDBUG Include BedBug Debugger
551 CFG_CMD_CACHE icache, dcache
552 CFG_CMD_CONSOLE coninfo
553 CFG_CMD_DATE * support for RTC, date/time...
554 CFG_CMD_DHCP DHCP support
555 CFG_CMD_ECHO * echo arguments
556 CFG_CMD_EEPROM * EEPROM read/write support
557 CFG_CMD_ELF bootelf, bootvx
559 CFG_CMD_FDC * Floppy Disk Support
560 CFG_CMD_FDOS * Dos diskette Support
561 CFG_CMD_FLASH flinfo, erase, protect
562 CFG_CMD_FPGA FPGA device initialization support
563 CFG_CMD_I2C * I2C serial bus support
564 CFG_CMD_IDE * IDE harddisk support
566 CFG_CMD_IMMAP * IMMR dump support
567 CFG_CMD_IRQ * irqinfo
571 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
573 CFG_CMD_MII MII utility commands
574 CFG_CMD_NET bootp, tftpboot, rarpboot
575 CFG_CMD_PCI * pciinfo
576 CFG_CMD_PCMCIA * PCMCIA support
577 CFG_CMD_REGINFO * Register dump
578 CFG_CMD_RUN run command in env variable
579 CFG_CMD_SCSI * SCSI Support
580 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
581 CFG_CMD_SPI * SPI serial bus support
582 CFG_CMD_USB * USB support
583 CFG_CMD_BSP * Board SPecific functions
584 -----------------------------------------------
587 CFG_CMD_DFL Default configuration; at the moment
588 this is includes all commands, except
589 the ones marked with "*" in the list
592 If you don't define CONFIG_COMMANDS it defaults to
593 CFG_CMD_DFL in include/cmd_confdefs.h. A board can
594 override the default settings in the respective
597 EXAMPLE: If you want all functions except of network
598 support you can write:
600 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
603 Note: Don't enable the "icache" and "dcache" commands
604 (configuration option CFG_CMD_CACHE) unless you know
605 what you (and your U-Boot users) are doing. Data
606 cache cannot be enabled on systems like the 8xx or
607 8260 (where accesses to the IMMR region must be
608 uncached), and it cannot be disabled on all other
609 systems where we (mis-) use the data cache to hold an
610 initial stack and some data.
613 XXX - this list needs to get updated!
617 If this variable is defined, it enables watchdog
618 support. There must support in the platform specific
619 code for a watchdog. For the 8xx and 8260 CPUs, the
620 SIU Watchdog feature is enabled in the SYPCR
624 CONFIG_VERSION_VARIABLE
625 If this variable is defined, an environment variable
626 named "ver" is created by U-Boot showing the U-Boot
627 version as printed by the "version" command.
628 This variable is readonly.
632 When CFG_CMD_DATE is selected, the type of the RTC
633 has to be selected, too. Define exactly one of the
636 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
637 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
638 CONFIG_RTC_MC146818 - use MC146818 RTC
639 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
640 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
641 CONFIG_RTC_DS164x - use Dallas DS164x RTC
645 When CONFIG_TIMESTAMP is selected, the timestamp
646 (date and time) of an image is printed by image
647 commands like bootm or iminfo. This option is
648 automatically enabled when you select CFG_CMD_DATE .
651 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
652 and/or CONFIG_ISO_PARTITION
654 If IDE or SCSI support is enabled (CFG_CMD_IDE or
655 CFG_CMD_SCSI) you must configure support for at least
656 one partition type as well.
659 CONFIG_IDE_RESET_ROUTINE
661 Set this to define that instead of a reset Pin, the
662 routine ide_set_reset(int idereset) will be used.
667 Set this to enable ATAPI support.
670 At the moment only there is only support for the
671 SYM53C8XX SCSI controller; define
672 CONFIG_SCSI_SYM53C8XX to enable it.
674 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
675 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
676 CFG_SCSI_MAX_LUN] can be adjusted to define the
677 maximum numbers of LUNs, SCSI ID's and target
679 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
681 - NETWORK Support (PCI):
683 Support for Intel 82557/82559/82559ER chips.
684 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
685 write routine for first time initialisation.
688 Support for Digital 2114x chips.
689 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
690 modem chip initialisation (KS8761/QS6611).
693 Support for National dp83815 chips.
696 Support for National dp8382[01] gigabit chips.
698 - NETWORK Support (other):
700 CONFIG_DRIVER_LAN91C96
701 Support for SMSC's LAN91C96 chips.
704 Define this to hold the physical address
705 of the LAN91C96's I/O space
707 CONFIG_LAN91C96_USE_32_BIT
708 Define this to enable 32 bit addressing
711 At the moment only the UHCI host controller is
712 supported (PIP405, MIP405); define
713 CONFIG_USB_UHCI to enable it.
714 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
715 end define CONFIG_USB_STORAGE to enable the USB
718 Supported are USB Keyboards and USB Floppy drives
724 Define this to enable standard (PC-Style) keyboard
728 Standard PC keyboard driver with US (is default) and
729 GERMAN key layout (switch via environment 'keymap=de') support.
730 Export function i8042_kbd_init, i8042_tstc and i8042_getc
731 for cfb_console. Supports cursor blinking.
736 Define this to enable video support (for output to
741 Enable Chips & Technologies 69000 Video chip
743 CONFIG_VIDEO_SMI_LYNXEM
744 Enable Silicon Motion SMI 712/710/810 Video chip
745 Videomode are selected via environment 'videomode' with
746 standard LiLo mode numbers.
747 Following modes are supported (* is default):
749 800x600 1024x768 1280x1024
750 256 (8bit) 303* 305 307
751 65536 (16bit) 314 317 31a
752 16,7 Mill (24bit) 315 318 31b
753 (i.e. setenv videomode 317; saveenv; reset;)
755 CONFIG_VIDEO_SED13806
756 Enable Epson SED13806 driver. This driver supports 8bpp
757 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
758 or CONFIG_VIDEO_SED13806_16BPP
761 - LCD Support: CONFIG_LCD
763 Define this to enable LCD support (for output to LCD
764 display); also select one of the supported displays
765 by defining one of these:
767 CONFIG_NEC_NL6648AC33:
769 NEC NL6648AC33-18. Active, color, single scan.
771 CONFIG_NEC_NL6648BC20
773 NEC NL6648BC20-08. 6.5", 640x480.
774 Active, color, single scan.
778 Sharp 320x240. Active, color, single scan.
779 It isn't 16x9, and I am not sure what it is.
781 CONFIG_SHARP_LQ64D341
783 Sharp LQ64D341 display, 640x480.
784 Active, color, single scan.
788 HLD1045 display, 640x480.
789 Active, color, single scan.
793 Optrex CBL50840-2 NF-FW 99 22 M5
795 Hitachi LMG6912RPFC-00T
799 320x240. Black & white.
801 Normally display is black on white background; define
802 CFG_WHITE_ON_BLACK to get it inverted.
804 - Spash Screen Support: CONFIG_SPLASH_SCREEN
806 If this option is set, the environment is checked for
807 a variable "splashimage". If found, the usual display
808 of logo, copyright and system information on the LCD
809 is supressed and the BMP image at the address
810 specified in "splashimage" is loaded instead. The
811 console is redirected to the "nulldev", too. This
812 allows for a "silent" boot where a splash screen is
813 loaded very quickly after power-on.
821 Define a default value for ethernet address to use
822 for the respective ethernet interface, in case this
823 is not determined automatically.
828 Define a default value for the IP address to use for
829 the default ethernet interface, in case this is not
830 determined through e.g. bootp.
835 Defines a default value for theIP address of a TFTP
836 server to contact when using the "tftboot" command.
838 - BOOTP Recovery Mode:
839 CONFIG_BOOTP_RANDOM_DELAY
841 If you have many targets in a network that try to
842 boot using BOOTP, you may want to avoid that all
843 systems send out BOOTP requests at precisely the same
844 moment (which would happen for instance at recovery
845 from a power failure, when all systems will try to
846 boot, thus flooding the BOOTP server. Defining
847 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
848 inserted before sending out BOOTP requests. The
849 following delays are insterted then:
851 1st BOOTP request: delay 0 ... 1 sec
852 2nd BOOTP request: delay 0 ... 2 sec
853 3rd BOOTP request: delay 0 ... 4 sec
855 BOOTP requests: delay 0 ... 8 sec
857 - Status LED: CONFIG_STATUS_LED
859 Several configurations allow to display the current
860 status using a LED. For instance, the LED will blink
861 fast while running U-Boot code, stop blinking as
862 soon as a reply to a BOOTP request was received, and
863 start blinking slow once the Linux kernel is running
864 (supported by a status LED driver in the Linux
865 kernel). Defining CONFIG_STATUS_LED enables this
868 - CAN Support: CONFIG_CAN_DRIVER
870 Defining CONFIG_CAN_DRIVER enables CAN driver support
871 on those systems that support this (optional)
872 feature, like the TQM8xxL modules.
874 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
876 Enables I2C serial bus commands. If this is selected,
877 either CONFIG_HARD_I2C or CONFIG_SOFT_I2C must be defined
878 to include the appropriate I2C driver.
880 See also: common/cmd_i2c.c for a description of the
881 command line interface.
886 Selects the CPM hardware driver for I2C.
890 Use software (aka bit-banging) driver instead of CPM
891 or similar hardware support for I2C. This is configured
892 via the following defines.
896 (Optional). Any commands necessary to enable I2C
897 controller or configure ports.
901 (Only for MPC8260 CPU). The I/O port to use (the code
902 assumes both bits are on the same port). Valid values
903 are 0..3 for ports A..D.
907 The code necessary to make the I2C data line active
908 (driven). If the data line is open collector, this
913 The code necessary to make the I2C data line tri-stated
914 (inactive). If the data line is open collector, this
919 Code that returns TRUE if the I2C data line is high,
924 If <bit> is TRUE, sets the I2C data line high. If it
925 is FALSE, it clears it (low).
929 If <bit> is TRUE, sets the I2C clock line high. If it
930 is FALSE, it clears it (low).
934 This delay is invoked four times per clock cycle so this
935 controls the rate of data transfer. The data rate thus
936 is 1 / (I2C_DELAY * 4).
940 When a board is reset during an i2c bus transfer
941 chips might think that the current transfer is still
942 in progress. On some boards it is possible to access
943 the i2c SCLK line directly, either by using the
944 processor pin as a GPIO or by having a second pin
945 connected to the bus. If this option is defined a
946 custom i2c_init_board() routine in boards/xxx/board.c
947 is run early in the boot sequence.
949 - SPI Support: CONFIG_SPI
951 Enables SPI driver (so far only tested with
952 SPI EEPROM, also an instance works with Crystal A/D and
953 D/As on the SACSng board)
957 Enables extended (16-bit) SPI EEPROM addressing.
958 (symmetrical to CONFIG_I2C_X)
962 Enables a software (bit-bang) SPI driver rather than
963 using hardware support. This is a general purpose
964 driver that only requires three general I/O port pins
965 (two outputs, one input) to function. If this is
966 defined, the board configuration must define several
967 SPI configuration items (port pins to use, etc). For
968 an example, see include/configs/sacsng.h.
970 - FPGA Support: CONFIG_FPGA_COUNT
972 Specify the number of FPGA devices to support.
976 Used to specify the types of FPGA devices. For
978 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
980 CFG_FPGA_PROG_FEEDBACK
982 Enable printing of hash marks during FPGA
987 Enable checks on FPGA configuration interface busy
988 status by the configuration function. This option
989 will require a board or device specific function to
994 If defined, a function that provides delays in the
995 FPGA configuration driver.
999 Allow Control-C to interrupt FPGA configuration
1001 CFG_FPGA_CHECK_ERROR
1003 Check for configuration errors during FPGA bitfile
1004 loading. For example, abort during Virtex II
1005 configuration if the INIT_B line goes low (which
1006 indicated a CRC error).
1010 Maximum time to wait for the INIT_B line to deassert
1011 after PROB_B has been deasserted during a Virtex II
1012 FPGA configuration sequence. The default time is 500 mS.
1016 Maximum time to wait for BUSY to deassert during
1017 Virtex II FPGA configuration. The default is 5 mS.
1019 CFG_FPGA_WAIT_CONFIG
1021 Time to wait after FPGA configuration. The default is
1024 - FPGA Support: CONFIG_FPGA_COUNT
1026 Specify the number of FPGA devices to support.
1030 Used to specify the types of FPGA devices. For example,
1031 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1033 CFG_FPGA_PROG_FEEDBACK
1035 Enable printing of hash marks during FPGA configuration.
1039 Enable checks on FPGA configuration interface busy
1040 status by the configuration function. This option
1041 will require a board or device specific function to
1046 If defined, a function that provides delays in the FPGA
1047 configuration driver.
1049 CFG_FPGA_CHECK_CTRLC
1050 Allow Control-C to interrupt FPGA configuration
1052 CFG_FPGA_CHECK_ERROR
1054 Check for configuration errors during FPGA bitfile
1055 loading. For example, abort during Virtex II
1056 configuration if the INIT_B line goes low (which
1057 indicated a CRC error).
1061 Maximum time to wait for the INIT_B line to deassert
1062 after PROB_B has been deasserted during a Virtex II
1063 FPGA configuration sequence. The default time is 500
1068 Maximum time to wait for BUSY to deassert during
1069 Virtex II FPGA configuration. The default is 5 mS.
1071 CFG_FPGA_WAIT_CONFIG
1073 Time to wait after FPGA configuration. The default is
1076 - Configuration Management:
1079 If defined, this string will be added to the U-Boot
1080 version information (U_BOOT_VERSION)
1082 - Vendor Parameter Protection:
1084 U-Boot considers the values of the environment
1085 variables "serial#" (Board Serial Number) and
1086 "ethaddr" (Ethernet Address) to bb parameters that
1087 are set once by the board vendor / manufacturer, and
1088 protects these variables from casual modification by
1089 the user. Once set, these variables are read-only,
1090 and write or delete attempts are rejected. You can
1091 change this behviour:
1093 If CONFIG_ENV_OVERWRITE is #defined in your config
1094 file, the write protection for vendor parameters is
1095 completely disabled. Anybody can change or delete
1098 Alternatively, if you #define _both_ CONFIG_ETHADDR
1099 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1100 ethernet address is installed in the environment,
1101 which can be changed exactly ONCE by the user. [The
1102 serial# is unaffected by this, i. e. it remains
1108 Define this variable to enable the reservation of
1109 "protected RAM", i. e. RAM which is not overwritten
1110 by U-Boot. Define CONFIG_PRAM to hold the number of
1111 kB you want to reserve for pRAM. You can overwrite
1112 this default value by defining an environment
1113 variable "pram" to the number of kB you want to
1114 reserve. Note that the board info structure will
1115 still show the full amount of RAM. If pRAM is
1116 reserved, a new environment variable "mem" will
1117 automatically be defined to hold the amount of
1118 remaining RAM in a form that can be passed as boot
1119 argument to Linux, for instance like that:
1121 setenv bootargs ... mem=\$(mem)
1124 This way you can tell Linux not to use this memory,
1125 either, which results in a memory region that will
1126 not be affected by reboots.
1128 *WARNING* If your board configuration uses automatic
1129 detection of the RAM size, you must make sure that
1130 this memory test is non-destructive. So far, the
1131 following board configurations are known to be
1134 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1135 HERMES, IP860, RPXlite, LWMON, LANTEC,
1136 PCU_E, FLAGADM, TQM8260
1141 Define this variable to stop the system in case of a
1142 fatal error, so that you have to reset it manually.
1143 This is probably NOT a good idea for an embedded
1144 system where you want to system to reboot
1145 automatically as fast as possible, but it may be
1146 useful during development since you can try to debug
1147 the conditions that lead to the situation.
1149 CONFIG_NET_RETRY_COUNT
1151 This variable defines the number of retries for
1152 network operations like ARP, RARP, TFTP, or BOOTP
1153 before giving up the operation. If not defined, a
1154 default value of 5 is used.
1156 - Command Interpreter:
1159 Define this variable to enable the "hush" shell (from
1160 Busybox) as command line interpreter, thus enabling
1161 powerful command line syntax like
1162 if...then...else...fi conditionals or `&&' and '||'
1163 constructs ("shell scripts").
1165 If undefined, you get the old, much simpler behaviour
1166 with a somewhat smaller memory footprint.
1171 This defines the secondary prompt string, which is
1172 printed when the command interpreter needs more input
1173 to complete a command. Usually "> ".
1177 In the current implementation, the local variables
1178 space and global environment variables space are
1179 separated. Local variables are those you define by
1180 simply typing like `name=value'. To access a local
1181 variable later on, you have write `$name' or
1182 `${name}'; variable directly by typing say `$name' at
1185 Global environment variables are those you use
1186 setenv/printenv to work with. To run a command stored
1187 in such a variable, you need to use the run command,
1188 and you must not use the '$' sign to access them.
1190 To store commands and special characters in a
1191 variable, please use double quotation marks
1192 surrounding the whole text of the variable, instead
1193 of the backslashes before semicolons and special
1196 - Default Environment
1197 CONFIG_EXTRA_ENV_SETTINGS
1199 Define this to contain any number of null terminated
1200 strings (variable = value pairs) that will be part of
1201 the default enviroment compiled into the boot image.
1203 For example, place something like this in your
1204 board's config file:
1206 #define CONFIG_EXTRA_ENV_SETTINGS \
1210 Warning: This method is based on knowledge about the
1211 internal format how the environment is stored by the
1212 U-Boot code. This is NOT an official, exported
1213 interface! Although it is unlikely that this format
1214 will change soon, but there is no guarantee either.
1215 You better know what you are doing here.
1217 Note: overly (ab)use of the default environment is
1218 discouraged. Make sure to check other ways to preset
1219 the environment like the autoscript function or the
1222 - Show boot progress
1223 CONFIG_SHOW_BOOT_PROGRESS
1225 Defining this option allows to add some board-
1226 specific code (calling a user-provided function
1227 "show_boot_progress(int)") that enables you to show
1228 the system's boot progress on some display (for
1229 example, some LED's) on your board. At the moment,
1230 the following checkpoints are implemented:
1233 1 common/cmd_bootm.c before attempting to boot an image
1234 -1 common/cmd_bootm.c Image header has bad magic number
1235 2 common/cmd_bootm.c Image header has correct magic number
1236 -2 common/cmd_bootm.c Image header has bad checksum
1237 3 common/cmd_bootm.c Image header has correct checksum
1238 -3 common/cmd_bootm.c Image data has bad checksum
1239 4 common/cmd_bootm.c Image data has correct checksum
1240 -4 common/cmd_bootm.c Image is for unsupported architecture
1241 5 common/cmd_bootm.c Architecture check OK
1242 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1243 6 common/cmd_bootm.c Image Type check OK
1244 -6 common/cmd_bootm.c gunzip uncompression error
1245 -7 common/cmd_bootm.c Unimplemented compression type
1246 7 common/cmd_bootm.c Uncompression OK
1247 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1248 8 common/cmd_bootm.c Image Type check OK
1249 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1250 9 common/cmd_bootm.c Start initial ramdisk verification
1251 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1252 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1253 10 common/cmd_bootm.c Ramdisk header is OK
1254 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1255 11 common/cmd_bootm.c Ramdisk data has correct checksum
1256 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1257 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1258 13 common/cmd_bootm.c Start multifile image verification
1259 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1260 15 common/cmd_bootm.c All preparation done, transferring control to OS
1262 -1 common/cmd_doc.c Bad usage of "doc" command
1263 -1 common/cmd_doc.c No boot device
1264 -1 common/cmd_doc.c Unknown Chip ID on boot device
1265 -1 common/cmd_doc.c Read Error on boot device
1266 -1 common/cmd_doc.c Image header has bad magic number
1268 -1 common/cmd_ide.c Bad usage of "ide" command
1269 -1 common/cmd_ide.c No boot device
1270 -1 common/cmd_ide.c Unknown boot device
1271 -1 common/cmd_ide.c Unknown partition table
1272 -1 common/cmd_ide.c Invalid partition type
1273 -1 common/cmd_ide.c Read Error on boot device
1274 -1 common/cmd_ide.c Image header has bad magic number
1276 -1 common/cmd_nvedit.c Environment not changable, but has bad CRC
1282 [so far only for SMDK2400 and TRAB boards]
1284 - Modem support endable:
1285 CONFIG_MODEM_SUPPORT
1287 - RTS/CTS Flow control enable:
1290 - Modem debug support:
1291 CONFIG_MODEM_SUPPORT_DEBUG
1293 Enables debugging stuff (char screen[1024], dbg())
1294 for modem support. Useful only with BDI2000.
1298 In the target system modem support is enabled when a
1299 specific key (key combination) is pressed during
1300 power-on. Otherwise U-Boot will boot normally
1301 (autoboot). The key_pressed() fuction is called from
1302 board_init(). Currently key_pressed() is a dummy
1303 function, returning 1 and thus enabling modem
1306 If there are no modem init strings in the
1307 environment, U-Boot proceed to autoboot; the
1308 previous output (banner, info printfs) will be
1311 See also: doc/README.Modem
1316 Configuration Settings:
1317 -----------------------
1319 - CFG_LONGHELP: Defined when you want long help messages included;
1320 undefine this when you're short of memory.
1322 - CFG_PROMPT: This is what U-Boot prints on the console to
1323 prompt for user input.
1325 - CFG_CBSIZE: Buffer size for input from the Console
1327 - CFG_PBSIZE: Buffer size for Console output
1329 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1331 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1332 the application (usually a Linux kernel) when it is
1335 - CFG_BAUDRATE_TABLE:
1336 List of legal baudrate settings for this board.
1338 - CFG_CONSOLE_INFO_QUIET
1339 Suppress display of console information at boot.
1341 - CFG_CONSOLE_IS_IN_ENV
1342 If the board specific function
1343 extern int overwrite_console (void);
1344 returns 1, the stdin, stderr and stdout are switched to the
1345 serial port, else the settings in the environment are used.
1347 - CFG_CONSOLE_OVERWRITE_ROUTINE
1348 Enable the call to overwrite_console().
1350 - CFG_CONSOLE_ENV_OVERWRITE
1351 Enable overwrite of previous console environment settings.
1353 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1354 Begin and End addresses of the area used by the
1358 Enable an alternate, more extensive memory test.
1360 - CFG_TFTP_LOADADDR:
1361 Default load address for network file downloads
1363 - CFG_LOADS_BAUD_CHANGE:
1364 Enable temporary baudrate change while serial download
1367 Physical start address of SDRAM. _Must_ be 0 here.
1370 Physical start address of Motherboard I/O (if using a
1374 Physical start address of Flash memory.
1377 Physical start address of boot monitor code (set by
1378 make config files to be same as the text base address
1379 (TEXT_BASE) used when linking) - same as
1380 CFG_FLASH_BASE when booting from flash.
1383 Size of memory reserved for monitor code
1386 Size of DRAM reserved for malloc() use.
1389 Maximum size of memory mapped by the startup code of
1390 the Linux kernel; all data that must be processed by
1391 the Linux kernel (bd_info, boot arguments, eventually
1392 initrd image) must be put below this limit.
1394 - CFG_MAX_FLASH_BANKS:
1395 Max number of Flash memory banks
1397 - CFG_MAX_FLASH_SECT:
1398 Max number of sectors on a Flash chip
1400 - CFG_FLASH_ERASE_TOUT:
1401 Timeout for Flash erase operations (in ms)
1403 - CFG_FLASH_WRITE_TOUT:
1404 Timeout for Flash write operations (in ms)
1406 - CFG_DIRECT_FLASH_TFTP:
1408 Enable TFTP transfers directly to flash memory;
1409 without this option such a download has to be
1410 performed in two steps: (1) download to RAM, and (2)
1411 copy from RAM to flash.
1413 The two-step approach is usually more reliable, since
1414 you can check if the download worked before you erase
1415 the flash, but in some situations (when sytem RAM is
1416 too limited to allow for a tempory copy of the
1417 downloaded image) this option may be very useful.
1420 Define if the flash driver uses extra elements in the
1421 common flash structure for storing flash geometry
1423 The following definitions that deal with the placement and management
1424 of environment data (variable area); in general, we support the
1425 following configurations:
1427 - CFG_ENV_IS_IN_FLASH:
1429 Define this if the environment is in flash memory.
1431 a) The environment occupies one whole flash sector, which is
1432 "embedded" in the text segment with the U-Boot code. This
1433 happens usually with "bottom boot sector" or "top boot
1434 sector" type flash chips, which have several smaller
1435 sectors at the start or the end. For instance, such a
1436 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1437 such a case you would place the environment in one of the
1438 4 kB sectors - with U-Boot code before and after it. With
1439 "top boot sector" type flash chips, you would put the
1440 environment in one of the last sectors, leaving a gap
1441 between U-Boot and the environment.
1445 Offset of environment data (variable area) to the
1446 beginning of flash memory; for instance, with bottom boot
1447 type flash chips the second sector can be used: the offset
1448 for this sector is given here.
1450 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1454 This is just another way to specify the start address of
1455 the flash sector containing the environment (instead of
1458 - CFG_ENV_SECT_SIZE:
1460 Size of the sector containing the environment.
1463 b) Sometimes flash chips have few, equal sized, BIG sectors.
1464 In such a case you don't want to spend a whole sector for
1469 If you use this in combination with CFG_ENV_IS_IN_FLASH
1470 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1471 of this flash sector for the environment. This saves
1472 memory for the RAM copy of the environment.
1474 It may also save flash memory if you decide to use this
1475 when your environment is "embedded" within U-Boot code,
1476 since then the remainder of the flash sector could be used
1477 for U-Boot code. It should be pointed out that this is
1478 STRONGLY DISCOURAGED from a robustness point of view:
1479 updating the environment in flash makes it always
1480 necessary to erase the WHOLE sector. If something goes
1481 wrong before the contents has been restored from a copy in
1482 RAM, your target system will be dead.
1484 - CFG_ENV_ADDR_REDUND
1487 These settings describe a second storage area used to hold
1488 a redundand copy of the environment data, so that there is
1489 a valid backup copy in case there is a power failure during
1490 a "saveenv" operation.
1492 BE CAREFUL! Any changes to the flash layout, and some changes to the
1493 source code will make it necessary to adapt <board>/u-boot.lds*
1497 - CFG_ENV_IS_IN_NVRAM:
1499 Define this if you have some non-volatile memory device
1500 (NVRAM, battery buffered SRAM) which you want to use for the
1506 These two #defines are used to determin the memory area you
1507 want to use for environment. It is assumed that this memory
1508 can just be read and written to, without any special
1511 BE CAREFUL! The first access to the environment happens quite early
1512 in U-Boot initalization (when we try to get the setting of for the
1513 console baudrate). You *MUST* have mappend your NVRAM area then, or
1516 Please note that even with NVRAM we still use a copy of the
1517 environment in RAM: we could work on NVRAM directly, but we want to
1518 keep settings there always unmodified except somebody uses "saveenv"
1519 to save the current settings.
1522 - CFG_ENV_IS_IN_EEPROM:
1524 Use this if you have an EEPROM or similar serial access
1525 device and a driver for it.
1530 These two #defines specify the offset and size of the
1531 environment area within the total memory of your EEPROM.
1533 - CFG_I2C_EEPROM_ADDR:
1534 If defined, specified the chip address of the EEPROM device.
1535 The default address is zero.
1537 - CFG_EEPROM_PAGE_WRITE_BITS:
1538 If defined, the number of bits used to address bytes in a
1539 single page in the EEPROM device. A 64 byte page, for example
1540 would require six bits.
1542 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1543 If defined, the number of milliseconds to delay between
1544 page writes. The default is zero milliseconds.
1546 - CFG_I2C_EEPROM_ADDR_LEN:
1547 The length in bytes of the EEPROM memory array address. Note
1548 that this is NOT the chip address length!
1551 The size in bytes of the EEPROM device.
1554 - CFG_SPI_INIT_OFFSET
1556 Defines offset to the initial SPI buffer area in DPRAM. The
1557 area is used at an early stage (ROM part) if the environment
1558 is configured to reside in the SPI EEPROM: We need a 520 byte
1559 scratch DPRAM area. It is used between the two initialization
1560 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1561 to be a good choice since it makes it far enough from the
1562 start of the data area as well as from the stack pointer.
1564 Please note that the environment is read-only as long as the monitor
1565 has been relocated to RAM and a RAM copy of the environment has been
1566 created; also, when using EEPROM you will have to use getenv_r()
1567 until then to read environment variables.
1569 The environment is protected by a CRC32 checksum. Before the monitor
1570 is relocated into RAM, as a result of a bad CRC you will be working
1571 with the compiled-in default environment - *silently*!!! [This is
1572 necessary, because the first environment variable we need is the
1573 "baudrate" setting for the console - if we have a bad CRC, we don't
1574 have any device yet where we could complain.]
1576 Note: once the monitor has been relocated, then it will complain if
1577 the default environment is used; a new CRC is computed as soon as you
1578 use the "saveenv" command to store a valid environment.
1581 Low Level (hardware related) configuration options:
1582 ---------------------------------------------------
1584 - CFG_CACHELINE_SIZE:
1585 Cache Line Size of the CPU.
1588 Default address of the IMMR after system reset.
1589 Needed on some 8260 systems (MPC8260ADS and RPXsuper)
1590 to be able to adjust the position of the IMMR
1591 register after a reset.
1593 - Floppy Disk Support:
1594 CFG_FDC_DRIVE_NUMBER
1596 the default drive number (default value 0)
1600 defines the spacing between fdc chipset registers
1605 defines the offset of register from address. It
1606 depends on which part of the data bus is connected to
1607 the fdc chipset. (default value 0)
1609 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1610 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1613 if CFG_FDC_HW_INIT is defined, then the function
1614 fdc_hw_init() is called at the beginning of the FDC
1615 setup. fdc_hw_init() must be provided by the board
1616 source code. It is used to make hardware dependant
1619 - CFG_IMMR: Physical address of the Internal Memory Mapped
1620 Register; DO NOT CHANGE! (11-4)
1621 [MPC8xx systems only]
1623 - CFG_INIT_RAM_ADDR:
1625 Start address of memory area tha can be used for
1626 initial data and stack; please note that this must be
1627 writable memory that is working WITHOUT special
1628 initialization, i. e. you CANNOT use normal RAM which
1629 will become available only after programming the
1630 memory controller and running certain initialization
1633 U-Boot uses the following memory types:
1634 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1635 - MPC824X: data cache
1636 - PPC4xx: data cache
1638 - CFG_GBL_DATA_OFFSET:
1640 Offset of the initial data structure in the memory
1641 area defined by CFG_INIT_RAM_ADDR. Usually
1642 CFG_GBL_DATA_OFFSET is chosen such that the initial
1643 data is located at the end of the available space
1644 (sometimes written as (CFG_INIT_RAM_END -
1645 CFG_INIT_DATA_SIZE), and the initial stack is just
1646 below that area (growing from (CFG_INIT_RAM_ADDR +
1647 CFG_GBL_DATA_OFFSET) downward.
1650 On the MPC824X (or other systems that use the data
1651 cache for initial memory) the address chosen for
1652 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1653 point to an otherwise UNUSED address space between
1654 the top of RAM and the start of the PCI space.
1656 - CFG_SIUMCR: SIU Module Configuration (11-6)
1658 - CFG_SYPCR: System Protection Control (11-9)
1660 - CFG_TBSCR: Time Base Status and Control (11-26)
1662 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1664 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1666 - CFG_SCCR: System Clock and reset Control Register (15-27)
1668 - CFG_OR_TIMING_SDRAM:
1672 periodic timer for refresh
1674 - CFG_DER: Debug Event Register (37-47)
1676 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1677 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1678 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1680 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1682 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1683 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1684 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1685 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1687 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1688 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1689 Machine Mode Register and Memory Periodic Timer
1690 Prescaler definitions (SDRAM timing)
1692 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1693 enable I2C microcode relocation patch (MPC8xx);
1694 define relocation offset in DPRAM [DSP2]
1696 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1697 enable SPI microcode relocation patch (MPC8xx);
1698 define relocation offset in DPRAM [SCC4]
1701 Use OSCM clock mode on MBX8xx board. Be careful,
1702 wrong setting might damage your board. Read
1703 doc/README.MBX before setting this variable!
1705 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1706 Offset of the bootmode word in DPRAM used by post
1707 (Power On Self Tests). This definition overrides
1708 #define'd default value in commproc.h resp.
1711 Building the Software:
1712 ======================
1714 Building U-Boot has been tested in native PPC environments (on a
1715 PowerBook G3 running LinuxPPC 2000) and in cross environments
1716 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1719 If you are not using a native PPC environment, it is assumed that you
1720 have the GNU cross compiling tools available in your path and named
1721 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1722 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1723 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1726 CROSS_COMPILE = ppc_4xx-
1729 U-Boot is intended to be simple to build. After installing the
1730 sources you must configure U-Boot for one specific board type. This
1735 where "NAME_config" is the name of one of the existing
1736 configurations; the following names are supported:
1738 ADCIOP_config GTH_config TQM850L_config
1739 ADS860_config IP860_config TQM855L_config
1740 AR405_config IVML24_config TQM860L_config
1741 CANBT_config IVMS8_config WALNUT405_config
1742 CPCI405_config LANTEC_config cogent_common_config
1743 CPCIISER4_config MBX_config cogent_mpc8260_config
1744 CU824_config MBX860T_config cogent_mpc8xx_config
1745 ESTEEM192E_config RPXlite_config hermes_config
1746 ETX094_config RPXsuper_config hymod_config
1747 FADS823_config SM850_config lwmon_config
1748 FADS850SAR_config SPD823TS_config pcu_e_config
1749 FADS860T_config SXNI855T_config rsdproto_config
1750 FPS850L_config Sandpoint8240_config sbc8260_config
1751 GENIETV_config TQM823L_config PIP405_config
1752 GEN860T_config EBONY_config FPS860L_config
1753 ELPT860_config cmi_mpc5xx_config
1755 Note: for some board special configuration names may exist; check if
1756 additional information is available from the board vendor; for
1757 instance, the TQM8xxL systems run normally at 50 MHz and use a
1758 SCC for 10baseT ethernet; there are also systems with 80 MHz
1759 CPU clock, and an optional Fast Ethernet module is available
1760 for CPU's with FEC. You can select such additional "features"
1761 when chosing the configuration, i. e.
1764 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1766 make TQM860L_FEC_config
1767 - will configure for a TQM860L at 50MHz with FEC for ethernet
1769 make TQM860L_80MHz_config
1770 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1773 make TQM860L_FEC_80MHz_config
1774 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1776 make TQM823L_LCD_config
1777 - will configure for a TQM823L with U-Boot console on LCD
1779 make TQM823L_LCD_80MHz_config
1780 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1786 Finally, type "make all", and you should get some working U-Boot
1787 images ready for downlod to / installation on your system:
1789 - "u-boot.bin" is a raw binary image
1790 - "u-boot" is an image in ELF binary format
1791 - "u-boot.srec" is in Motorola S-Record format
1794 Please be aware that the Makefiles assume you are using GNU make, so
1795 for instance on NetBSD you might need to use "gmake" instead of
1799 If the system board that you have is not listed, then you will need
1800 to port U-Boot to your hardware platform. To do this, follow these
1803 1. Add a new configuration option for your board to the toplevel
1804 "Makefile" and to the "MAKEALL" script, using the existing
1805 entries as examples. Note that here and at many other places
1806 boards and other names are listed alphabetically sorted. Please
1808 2. Create a new directory to hold your board specific code. Add any
1809 files you need. In your board directory, you will need at least
1810 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1811 3. Create a new configuration file "include/configs/<board>.h" for
1813 3. If you're porting U-Boot to a new CPU, then also create a new
1814 directory to hold your CPU specific code. Add any files you need.
1815 4. Run "make <board>_config" with your new name.
1816 5. Type "make", and you should get a working "u-boot.srec" file
1817 to be installed on your target system.
1818 6. Debug and solve any problems that might arise.
1819 [Of course, this last step is much harder than it sounds.]
1822 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1823 ==============================================================
1825 If you have modified U-Boot sources (for instance added a new board
1826 or support for new devices, a new CPU, etc.) you are expected to
1827 provide feedback to the other developers. The feedback normally takes
1828 the form of a "patch", i. e. a context diff against a certain (latest
1829 official or latest in CVS) version of U-Boot sources.
1831 But before you submit such a patch, please verify that your modifi-
1832 cation did not break existing code. At least make sure that *ALL* of
1833 the supported boards compile WITHOUT ANY compiler warnings. To do so,
1834 just run the "MAKEALL" script, which will configure and build U-Boot
1835 for ALL supported system. Be warned, this will take a while. You can
1836 select which (cross) compiler to use py passing a `CROSS_COMPILE'
1837 environment variable to the script, i. e. to use the cross tools from
1838 MontaVista's Hard Hat Linux you can type
1840 CROSS_COMPILE=ppc_8xx- MAKEALL
1842 or to build on a native PowerPC system you can type
1844 CROSS_COMPILE=' ' MAKEALL
1846 See also "U-Boot Porting Guide" below.
1850 Monitor Commands - Overview:
1851 ============================
1853 go - start application at address 'addr'
1854 run - run commands in an environment variable
1855 bootm - boot application image from memory
1856 bootp - boot image via network using BootP/TFTP protocol
1857 tftpboot- boot image via network using TFTP protocol
1858 and env variables "ipaddr" and "serverip"
1859 (and eventually "gatewayip")
1860 rarpboot- boot image via network using RARP/TFTP protocol
1861 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
1862 loads - load S-Record file over serial line
1863 loadb - load binary file over serial line (kermit mode)
1865 mm - memory modify (auto-incrementing)
1866 nm - memory modify (constant address)
1867 mw - memory write (fill)
1869 cmp - memory compare
1870 crc32 - checksum calculation
1871 imd - i2c memory display
1872 imm - i2c memory modify (auto-incrementing)
1873 inm - i2c memory modify (constant address)
1874 imw - i2c memory write (fill)
1875 icrc32 - i2c checksum calculation
1876 iprobe - probe to discover valid I2C chip addresses
1877 iloop - infinite loop on address range
1878 isdram - print SDRAM configuration information
1879 sspi - SPI utility commands
1880 base - print or set address offset
1881 printenv- print environment variables
1882 setenv - set environment variables
1883 saveenv - save environment variables to persistent storage
1884 protect - enable or disable FLASH write protection
1885 erase - erase FLASH memory
1886 flinfo - print FLASH memory information
1887 bdinfo - print Board Info structure
1888 iminfo - print header information for application image
1889 coninfo - print console devices and informations
1890 ide - IDE sub-system
1891 loop - infinite loop on address range
1892 mtest - simple RAM test
1893 icache - enable or disable instruction cache
1894 dcache - enable or disable data cache
1895 reset - Perform RESET of the CPU
1896 echo - echo args to console
1897 version - print monitor version
1898 help - print online help
1899 ? - alias for 'help'
1902 Monitor Commands - Detailed Description:
1903 ========================================
1907 For now: just type "help <command>".
1910 Environment Variables:
1911 ======================
1913 U-Boot supports user configuration using Environment Variables which
1914 can be made persistent by saving to Flash memory.
1916 Environment Variables are set using "setenv", printed using
1917 "printenv", and saved to Flash using "saveenv". Using "setenv"
1918 without a value can be used to delete a variable from the
1919 environment. As long as you don't save the environment you are
1920 working with an in-memory copy. In case the Flash area containing the
1921 environment is erased by accident, a default environment is provided.
1923 Some configuration options can be set using Environment Variables:
1925 baudrate - see CONFIG_BAUDRATE
1927 bootdelay - see CONFIG_BOOTDELAY
1929 bootcmd - see CONFIG_BOOTCOMMAND
1931 bootargs - Boot arguments when booting an RTOS image
1933 bootfile - Name of the image to load with TFTP
1935 autoload - if set to "no" (any string beginning with 'n'),
1936 "bootp" will just load perform a lookup of the
1937 configuration from the BOOTP server, but not try to
1938 load any image using TFTP
1940 autostart - if set to "yes", an image loaded using the "bootp",
1941 "rarpboot", "tftpboot" or "diskboot" commands will
1942 be automatically started (by internally calling
1945 If set to "no", a standalone image passed to the
1946 "bootm" command will be copied to the load address
1947 (and eventually uncompressed), but NOT be started.
1948 This can be used to load and uncompress arbitrary
1951 initrd_high - restrict positioning of initrd images:
1952 If this variable is not set, initrd images will be
1953 copied to the highest possible address in RAM; this
1954 is usually what you want since it allows for
1955 maximum initrd size. If for some reason you want to
1956 make sure that the initrd image is loaded below the
1957 CFG_BOOTMAPSZ limit, you can set this environment
1958 variable to a value of "no" or "off" or "0".
1959 Alternatively, you can set it to a maximum upper
1960 address to use (U-Boot will still check that it
1961 does not overwrite the U-Boot stack and data).
1963 For instance, when you have a system with 16 MB
1964 RAM, and want to reseve 4 MB from use by Linux,
1965 you can do this by adding "mem=12M" to the value of
1966 the "bootargs" variable. However, now you must make
1967 sure, that the initrd image is placed in the first
1968 12 MB as well - this can be done with
1970 setenv initrd_high 00c00000
1972 ipaddr - IP address; needed for tftpboot command
1974 loadaddr - Default load address for commands like "bootp",
1975 "rarpboot", "tftpboot", "loadb" or "diskboot"
1977 loads_echo - see CONFIG_LOADS_ECHO
1979 serverip - TFTP server IP address; needed for tftpboot command
1981 bootretry - see CONFIG_BOOT_RETRY_TIME
1983 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
1985 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
1988 The following environment variables may be used and automatically
1989 updated by the network boot commands ("bootp" and "rarpboot"),
1990 depending the information provided by your boot server:
1992 bootfile - see above
1993 dnsip - IP address of your Domain Name Server
1994 gatewayip - IP address of the Gateway (Router) to use
1995 hostname - Target hostname
1997 netmask - Subnet Mask
1998 rootpath - Pathname of the root filesystem on the NFS server
1999 serverip - see above
2002 There are two special Environment Variables:
2004 serial# - contains hardware identification information such
2005 as type string and/or serial number
2006 ethaddr - Ethernet address
2008 These variables can be set only once (usually during manufacturing of
2009 the board). U-Boot refuses to delete or overwrite these variables
2010 once they have been set once.
2013 Further special Environment Variables:
2015 ver - Contains the U-Boot version string as printed
2016 with the "version" command. This variable is
2017 readonly (see CONFIG_VERSION_VARIABLE).
2020 Please note that changes to some configuration parameters may take
2021 only effect after the next boot (yes, that's just like Windoze :-).
2024 Note for Redundant Ethernet Interfaces:
2025 =======================================
2027 Some boards come with redundand ethernet interfaces; U-Boot supports
2028 such configurations and is capable of automatic selection of a
2029 "working" interface when needed. MAC assignemnt works as follows:
2031 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2032 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2033 "eth1addr" (=>eth1), "eth2addr", ...
2035 If the network interface stores some valid MAC address (for instance
2036 in SROM), this is used as default address if there is NO correspon-
2037 ding setting in the environment; if the corresponding environment
2038 variable is set, this overrides the settings in the card; that means:
2040 o If the SROM has a valid MAC address, and there is no address in the
2041 environment, the SROM's address is used.
2043 o If there is no valid address in the SROM, and a definition in the
2044 environment exists, then the value from the environment variable is
2047 o If both the SROM and the environment contain a MAC address, and
2048 both addresses are the same, this MAC address is used.
2050 o If both the SROM and the environment contain a MAC address, and the
2051 addresses differ, the value from the environment is used and a
2054 o If neither SROM nor the environment contain a MAC address, an error
2062 The "boot" commands of this monitor operate on "image" files which
2063 can be basicly anything, preceeded by a special header; see the
2064 definitions in include/image.h for details; basicly, the header
2065 defines the following image properties:
2067 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2068 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2070 Currently supported: Linux, NetBSD, VxWorks, QNX).
2071 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2072 IA64, MIPS, MIPS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2073 Currently supported: PowerPC).
2074 * Compression Type (Provisions for uncompressed, gzip, bzip2;
2075 Currently supported: uncompressed, gzip).
2081 The header is marked by a special Magic Number, and both the header
2082 and the data portions of the image are secured against corruption by
2089 Although U-Boot should support any OS or standalone application
2090 easily, Linux has always been in the focus during the design of
2093 U-Boot includes many features that so far have been part of some
2094 special "boot loader" code within the Linux kernel. Also, any
2095 "initrd" images to be used are no longer part of one big Linux image;
2096 instead, kernel and "initrd" are separate images. This implementation
2097 serves serveral purposes:
2099 - the same features can be used for other OS or standalone
2100 applications (for instance: using compressed images to reduce the
2101 Flash memory footprint)
2103 - it becomes much easier to port new Linux kernel versions because
2104 lots of low-level, hardware dependend stuff are done by U-Boot
2106 - the same Linux kernel image can now be used with different "initrd"
2107 images; of course this also means that different kernel images can
2108 be run with the same "initrd". This makes testing easier (you don't
2109 have to build a new "zImage.initrd" Linux image when you just
2110 change a file in your "initrd"). Also, a field-upgrade of the
2111 software is easier now.
2117 Porting Linux to U-Boot based systems:
2118 ---------------------------------------
2120 U-Boot cannot save you from doing all the necessary modifications to
2121 configure the Linux device drivers for use with your target hardware
2122 (no, we don't intend to provide a full virtual machine interface to
2125 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2127 Just make sure your machine specific header file (for instance
2128 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2129 Information structure as we define in include/u-boot.h, and make
2130 sure that your definition of IMAP_ADDR uses the same value as your
2131 U-Boot configuration in CFG_IMMR.
2134 Configuring the Linux kernel:
2135 -----------------------------
2137 No specific requirements for U-Boot. Make sure you have some root
2138 device (initial ramdisk, NFS) for your target system.
2141 Building a Linux Image:
2142 -----------------------
2144 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2145 not used. If you use recent kernel source, a new build target
2146 "uImage" will exist which automatically builds an image usable by
2147 U-Boot. Most older kernels also have support for a "pImage" target,
2148 which was introduced for our predecessor project PPCBoot and uses a
2149 100% compatible format.
2158 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2159 encapsulate a compressed Linux kernel image with header information,
2160 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2162 * build a standard "vmlinux" kernel image (in ELF binary format):
2164 * convert the kernel into a raw binary image:
2166 ${CROSS_COMPILE}-objcopy -O binary \
2167 -R .note -R .comment \
2168 -S vmlinux linux.bin
2170 * compress the binary image:
2174 * package compressed binary image for U-Boot:
2176 mkimage -A ppc -O linux -T kernel -C gzip \
2177 -a 0 -e 0 -n "Linux Kernel Image" \
2178 -d linux.bin.gz uImage
2181 The "mkimage" tool can also be used to create ramdisk images for use
2182 with U-Boot, either separated from the Linux kernel image, or
2183 combined into one file. "mkimage" encapsulates the images with a 64
2184 byte header containing information about target architecture,
2185 operating system, image type, compression method, entry points, time
2186 stamp, CRC32 checksums, etc.
2188 "mkimage" can be called in two ways: to verify existing images and
2189 print the header information, or to build new images.
2191 In the first form (with "-l" option) mkimage lists the information
2192 contained in the header of an existing U-Boot image; this includes
2193 checksum verification:
2195 tools/mkimage -l image
2196 -l ==> list image header information
2198 The second form (with "-d" option) is used to build a U-Boot image
2199 from a "data file" which is used as image payload:
2201 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2202 -n name -d data_file image
2203 -A ==> set architecture to 'arch'
2204 -O ==> set operating system to 'os'
2205 -T ==> set image type to 'type'
2206 -C ==> set compression type 'comp'
2207 -a ==> set load address to 'addr' (hex)
2208 -e ==> set entry point to 'ep' (hex)
2209 -n ==> set image name to 'name'
2210 -d ==> use image data from 'datafile'
2212 Right now, all Linux kernels use the same load address (0x00000000),
2213 but the entry point address depends on the kernel version:
2215 - 2.2.x kernels have the entry point at 0x0000000C,
2216 - 2.3.x and later kernels have the entry point at 0x00000000.
2218 So a typical call to build a U-Boot image would read:
2220 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2221 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2222 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2223 > examples/uImage.TQM850L
2224 Image Name: 2.4.4 kernel for TQM850L
2225 Created: Wed Jul 19 02:34:59 2000
2226 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2227 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2228 Load Address: 0x00000000
2229 Entry Point: 0x00000000
2231 To verify the contents of the image (or check for corruption):
2233 -> tools/mkimage -l examples/uImage.TQM850L
2234 Image Name: 2.4.4 kernel for TQM850L
2235 Created: Wed Jul 19 02:34:59 2000
2236 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2237 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2238 Load Address: 0x00000000
2239 Entry Point: 0x00000000
2241 NOTE: for embedded systems where boot time is critical you can trade
2242 speed for memory and install an UNCOMPRESSED image instead: this
2243 needs more space in Flash, but boots much faster since it does not
2244 need to be uncompressed:
2246 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2247 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2248 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2249 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2250 > examples/uImage.TQM850L-uncompressed
2251 Image Name: 2.4.4 kernel for TQM850L
2252 Created: Wed Jul 19 02:34:59 2000
2253 Image Type: PowerPC Linux Kernel Image (uncompressed)
2254 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2255 Load Address: 0x00000000
2256 Entry Point: 0x00000000
2259 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2260 when your kernel is intended to use an initial ramdisk:
2262 -> tools/mkimage -n 'Simple Ramdisk Image' \
2263 > -A ppc -O linux -T ramdisk -C gzip \
2264 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2265 Image Name: Simple Ramdisk Image
2266 Created: Wed Jan 12 14:01:50 2000
2267 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2268 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2269 Load Address: 0x00000000
2270 Entry Point: 0x00000000
2273 Installing a Linux Image:
2274 -------------------------
2276 To downloading a U-Boot image over the serial (console) interface,
2277 you must convert the image to S-Record format:
2279 objcopy -I binary -O srec examples/image examples/image.srec
2281 The 'objcopy' does not understand the information in the U-Boot
2282 image header, so the resulting S-Record file will be relative to
2283 address 0x00000000. To load it to a given address, you need to
2284 specify the target address as 'offset' parameter with the 'loads'
2287 Example: install the image to address 0x40100000 (which on the
2288 TQM8xxL is in the first Flash bank):
2290 => erase 40100000 401FFFFF
2296 ## Ready for S-Record download ...
2297 ~>examples/image.srec
2298 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2300 15989 15990 15991 15992
2301 [file transfer complete]
2303 ## Start Addr = 0x00000000
2306 You can check the success of the download using the 'iminfo' command;
2307 this includes a checksum verification so you can be sure no data
2308 corruption happened:
2312 ## Checking Image at 40100000 ...
2313 Image Name: 2.2.13 for initrd on TQM850L
2314 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2315 Data Size: 335725 Bytes = 327 kB = 0 MB
2316 Load Address: 00000000
2317 Entry Point: 0000000c
2318 Verifying Checksum ... OK
2325 The "bootm" command is used to boot an application that is stored in
2326 memory (RAM or Flash). In case of a Linux kernel image, the contents
2327 of the "bootargs" environment variable is passed to the kernel as
2328 parameters. You can check and modify this variable using the
2329 "printenv" and "setenv" commands:
2332 => printenv bootargs
2333 bootargs=root=/dev/ram
2335 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2337 => printenv bootargs
2338 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2341 ## Booting Linux kernel at 40020000 ...
2342 Image Name: 2.2.13 for NFS on TQM850L
2343 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2344 Data Size: 381681 Bytes = 372 kB = 0 MB
2345 Load Address: 00000000
2346 Entry Point: 0000000c
2347 Verifying Checksum ... OK
2348 Uncompressing Kernel Image ... OK
2349 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
2350 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2351 time_init: decrementer frequency = 187500000/60
2352 Calibrating delay loop... 49.77 BogoMIPS
2353 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2356 If you want to boot a Linux kernel with initial ram disk, you pass
2357 the memory addreses of both the kernel and the initrd image (PPBCOOT
2358 format!) to the "bootm" command:
2360 => imi 40100000 40200000
2362 ## Checking Image at 40100000 ...
2363 Image Name: 2.2.13 for initrd on TQM850L
2364 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2365 Data Size: 335725 Bytes = 327 kB = 0 MB
2366 Load Address: 00000000
2367 Entry Point: 0000000c
2368 Verifying Checksum ... OK
2370 ## Checking Image at 40200000 ...
2371 Image Name: Simple Ramdisk Image
2372 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2373 Data Size: 566530 Bytes = 553 kB = 0 MB
2374 Load Address: 00000000
2375 Entry Point: 00000000
2376 Verifying Checksum ... OK
2378 => bootm 40100000 40200000
2379 ## Booting Linux kernel at 40100000 ...
2380 Image Name: 2.2.13 for initrd on TQM850L
2381 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2382 Data Size: 335725 Bytes = 327 kB = 0 MB
2383 Load Address: 00000000
2384 Entry Point: 0000000c
2385 Verifying Checksum ... OK
2386 Uncompressing Kernel Image ... OK
2387 ## Loading RAMDisk Image at 40200000 ...
2388 Image Name: Simple Ramdisk Image
2389 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2390 Data Size: 566530 Bytes = 553 kB = 0 MB
2391 Load Address: 00000000
2392 Entry Point: 00000000
2393 Verifying Checksum ... OK
2394 Loading Ramdisk ... OK
2395 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
2396 Boot arguments: root=/dev/ram
2397 time_init: decrementer frequency = 187500000/60
2398 Calibrating delay loop... 49.77 BogoMIPS
2400 RAMDISK: Compressed image found at block 0
2401 VFS: Mounted root (ext2 filesystem).
2405 More About U-Boot Image Types:
2406 ------------------------------
2408 U-Boot supports the following image types:
2410 "Standalone Programs" are directly runnable in the environment
2411 provided by U-Boot; it is expected that (if they behave
2412 well) you can continue to work in U-Boot after return from
2413 the Standalone Program.
2414 "OS Kernel Images" are usually images of some Embedded OS which
2415 will take over control completely. Usually these programs
2416 will install their own set of exception handlers, device
2417 drivers, set up the MMU, etc. - this means, that you cannot
2418 expect to re-enter U-Boot except by resetting the CPU.
2419 "RAMDisk Images" are more or less just data blocks, and their
2420 parameters (address, size) are passed to an OS kernel that is
2422 "Multi-File Images" contain several images, typically an OS
2423 (Linux) kernel image and one or more data images like
2424 RAMDisks. This construct is useful for instance when you want
2425 to boot over the network using BOOTP etc., where the boot
2426 server provides just a single image file, but you want to get
2427 for instance an OS kernel and a RAMDisk image.
2429 "Multi-File Images" start with a list of image sizes, each
2430 image size (in bytes) specified by an "uint32_t" in network
2431 byte order. This list is terminated by an "(uint32_t)0".
2432 Immediately after the terminating 0 follow the images, one by
2433 one, all aligned on "uint32_t" boundaries (size rounded up to
2434 a multiple of 4 bytes).
2436 "Firmware Images" are binary images containing firmware (like
2437 U-Boot or FPGA images) which usually will be programmed to
2440 "Script files" are command sequences that will be executed by
2441 U-Boot's command interpreter; this feature is especially
2442 useful when you configure U-Boot to use a real shell (hush)
2443 as command interpreter.
2449 One of the features of U-Boot is that you can dynamically load and
2450 run "standalone" applications, which can use some resources of
2451 U-Boot like console I/O functions or interrupt services.
2453 Two simple examples are included with the sources:
2458 'examples/hello_world.c' contains a small "Hello World" Demo
2459 application; it is automatically compiled when you build U-Boot.
2460 It's configured to run at address 0x00040004, so you can play with it
2464 ## Ready for S-Record download ...
2465 ~>examples/hello_world.srec
2466 1 2 3 4 5 6 7 8 9 10 11 ...
2467 [file transfer complete]
2469 ## Start Addr = 0x00040004
2471 => go 40004 Hello World! This is a test.
2472 ## Starting application at 0x00040004 ...
2483 Hit any key to exit ...
2485 ## Application terminated, rc = 0x0
2487 Another example, which demonstrates how to register a CPM interrupt
2488 handler with the U-Boot code, can be found in 'examples/timer.c'.
2489 Here, a CPM timer is set up to generate an interrupt every second.
2490 The interrupt service routine is trivial, just printing a '.'
2491 character, but this is just a demo program. The application can be
2492 controlled by the following keys:
2494 ? - print current values og the CPM Timer registers
2495 b - enable interrupts and start timer
2496 e - stop timer and disable interrupts
2497 q - quit application
2500 ## Ready for S-Record download ...
2501 ~>examples/timer.srec
2502 1 2 3 4 5 6 7 8 9 10 11 ...
2503 [file transfer complete]
2505 ## Start Addr = 0x00040004
2508 ## Starting application at 0x00040004 ...
2511 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2514 [q, b, e, ?] Set interval 1000000 us
2517 [q, b, e, ?] ........
2518 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2521 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2524 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2527 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2529 [q, b, e, ?] ...Stopping timer
2531 [q, b, e, ?] ## Application terminated, rc = 0x0
2538 Over time, many people have reported problems when trying to used the
2539 "minicom" terminal emulation program for serial download. I (wd)
2540 consider minicom to be broken, and recommend not to use it. Under
2541 Unix, I recommend to use CKermit for general purpose use (and
2542 especially for kermit binary protocol download ("loadb" command), and
2543 use "cu" for S-Record download ("loads" command).
2548 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2549 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2551 Building requires a cross environment; it is known to work on
2552 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2553 need gmake since the Makefiles are not compatible with BSD make).
2554 Note that the cross-powerpc package does not install include files;
2555 attempting to build U-Boot will fail because <machine/ansi.h> is
2556 missing. This file has to be installed and patched manually:
2558 # cd /usr/pkg/cross/powerpc-netbsd/include
2560 # ln -s powerpc machine
2561 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2562 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2564 Native builds *don't* work due to incompatibilities between native
2565 and U-Boot include files.
2567 Booting assumes that (the first part of) the image booted is a
2568 stage-2 loader which in turn loads and then invokes the kernel
2569 proper. Loader sources will eventually appear in the NetBSD source
2570 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2571 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2575 Implementation Internals:
2576 =========================
2578 The following is not intended to be a complete description of every
2579 implementation detail. However, it should help to understand the
2580 inner workings of U-Boot and make it easier to port it to custom
2584 Initial Stack, Global Data:
2585 ---------------------------
2587 The implementation of U-Boot is complicated by the fact that U-Boot
2588 starts running out of ROM (flash memory), usually without access to
2589 system RAM (because the memory controller is not initialized yet).
2590 This means that we don't have writable Data or BSS segments, and BSS
2591 is not initialized as zero. To be able to get a C environment working
2592 at all, we have to allocate at least a minimal stack. Implementation
2593 options for this are defined and restricted by the CPU used: Some CPU
2594 models provide on-chip memory (like the IMMR area on MPC8xx and
2595 MPC826x processors), on others (parts of) the data cache can be
2596 locked as (mis-) used as memory, etc.
2598 Chris Hallinan posted a good summy of these issues to the
2599 u-boot-users mailing list:
2601 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2602 From: "Chris Hallinan" <clh@net1plus.com>
2603 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2606 Correct me if I'm wrong, folks, but the way I understand it
2607 is this: Using DCACHE as initial RAM for Stack, etc, does not
2608 require any physical RAM backing up the cache. The cleverness
2609 is that the cache is being used as a temporary supply of
2610 necessary storage before the SDRAM controller is setup. It's
2611 beyond the scope of this list to expain the details, but you
2612 can see how this works by studying the cache architecture and
2613 operation in the architecture and processor-specific manuals.
2615 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2616 is another option for the system designer to use as an
2617 initial stack/ram area prior to SDRAM being available. Either
2618 option should work for you. Using CS 4 should be fine if your
2619 board designers haven't used it for something that would
2620 cause you grief during the initial boot! It is frequently not
2623 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2624 with your processor/board/system design. The default value
2625 you will find in any recent u-boot distribution in
2626 Walnut405.h should work for you. I'd set it to a value larger
2627 than your SDRAM module. If you have a 64MB SDRAM module, set
2628 it above 400_0000. Just make sure your board has no resources
2629 that are supposed to respond to that address! That code in
2630 start.S has been around a while and should work as is when
2631 you get the config right.
2636 It is essential to remember this, since it has some impact on the C
2637 code for the initialization procedures:
2639 * Initialized global data (data segment) is read-only. Do not attempt
2642 * Do not use any unitialized global data (or implicitely initialized
2643 as zero data - BSS segment) at all - this is undefined, initiali-
2644 zation is performed later (when relocationg to RAM).
2646 * Stack space is very limited. Avoid big data buffers or things like
2649 Having only the stack as writable memory limits means we cannot use
2650 normal global data to share information beween the code. But it
2651 turned out that the implementation of U-Boot can be greatly
2652 simplified by making a global data structure (gd_t) available to all
2653 functions. We could pass a pointer to this data as argument to _all_
2654 functions, but this would bloat the code. Instead we use a feature of
2655 the GCC compiler (Global Register Variables) to share the data: we
2656 place a pointer (gd) to the global data into a register which we
2657 reserve for this purpose.
2659 When chosing a register for such a purpose we are restricted by the
2660 relevant (E)ABI specifications for the current architecture, and by
2661 GCC's implementation.
2663 For PowerPC, the following registers have specific use:
2666 R3-R4: parameter passing and return values
2667 R5-R10: parameter passing
2668 R13: small data area pointer
2672 (U-Boot also uses R14 as internal GOT pointer.)
2674 ==> U-Boot will use R29 to hold a pointer to the global data
2676 Note: on PPC, we could use a static initializer (since the
2677 address of the global data structure is known at compile time),
2678 but it turned out that reserving a register results in somewhat
2679 smaller code - although the code savings are not that big (on
2680 average for all boards 752 bytes for the whole U-Boot image,
2681 624 text + 127 data).
2683 On ARM, the following registers are used:
2685 R0: function argument word/integer result
2686 R1-R3: function argument word
2688 R10: stack limit (used only if stack checking if enabled)
2689 R11: argument (frame) pointer
2690 R12: temporary workspace
2693 R15: program counter
2695 ==> U-Boot will use R8 to hold a pointer to the global data
2702 U-Boot runs in system state and uses physical addresses, i.e. the
2703 MMU is not used either for address mapping nor for memory protection.
2705 The available memory is mapped to fixed addresses using the memory
2706 controller. In this process, a contiguous block is formed for each
2707 memory type (Flash, SDRAM, SRAM), even when it consists of several
2708 physical memory banks.
2710 U-Boot is installed in the first 128 kB of the first Flash bank (on
2711 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2712 booting and sizing and initializing DRAM, the code relocates itself
2713 to the upper end of DRAM. Immediately below the U-Boot code some
2714 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2715 configuration setting]. Below that, a structure with global Board
2716 Info data is placed, followed by the stack (growing downward).
2718 Additionally, some exception handler code is copied to the low 8 kB
2719 of DRAM (0x00000000 ... 0x00001FFF).
2721 So a typical memory configuration with 16 MB of DRAM could look like
2724 0x0000 0000 Exception Vector code
2727 0x0000 2000 Free for Application Use
2733 0x00FB FF20 Monitor Stack (Growing downward)
2734 0x00FB FFAC Board Info Data and permanent copy of global data
2735 0x00FC 0000 Malloc Arena
2738 0x00FE 0000 RAM Copy of Monitor Code
2739 ... eventually: LCD or video framebuffer
2740 ... eventually: pRAM (Protected RAM - unchanged by reset)
2741 0x00FF FFFF [End of RAM]
2744 System Initialization:
2745 ----------------------
2747 In the reset configuration, U-Boot starts at the reset entry point
2748 (on most PowerPC systens at address 0x00000100). Because of the reset
2749 configuration for CS0# this is a mirror of the onboard Flash memory.
2750 To be able to re-map memory U-Boot then jumps to it's link address.
2751 To be able to implement the initialization code in C, a (small!)
2752 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2753 which provide such a feature like MPC8xx or MPC8260), or in a locked
2754 part of the data cache. After that, U-Boot initializes the CPU core,
2755 the caches and the SIU.
2757 Next, all (potentially) available memory banks are mapped using a
2758 preliminary mapping. For example, we put them on 512 MB boundaries
2759 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2760 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2761 programmed for SDRAM access. Using the temporary configuration, a
2762 simple memory test is run that determines the size of the SDRAM
2765 When there is more than one SDRAM bank, and the banks are of
2766 different size, the larger is mapped first. For equal size, the first
2767 bank (CS2#) is mapped first. The first mapping is always for address
2768 0x00000000, with any additional banks following immediately to create
2769 contiguous memory starting from 0.
2771 Then, the monitor installs itself at the upper end of the SDRAM area
2772 and allocates memory for use by malloc() and for the global Board
2773 Info data; also, the exception vector code is copied to the low RAM
2774 pages, and the final stack is set up.
2776 Only after this relocation will you have a "normal" C environment;
2777 until that you are restricted in several ways, mostly because you are
2778 running from ROM, and because the code will have to be relocated to a
2782 U-Boot Porting Guide:
2783 ----------------------
2785 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
2789 int main (int argc, char *argv[])
2791 sighandler_t no_more_time;
2793 signal (SIGALRM, no_more_time);
2794 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
2796 if (available_money > available_manpower) {
2797 pay consultant to port U-Boot;
2801 Download latest U-Boot source;
2803 Subscribe to u-boot-users mailing list;
2806 email ("Hi, I am new to U-Boot, how do I get started?");
2810 Read the README file in the top level directory;
2811 Read http://www.denx.de/re/DPLG.html
2812 Read the source, Luke;
2815 if (available_money > toLocalCurrency ($2500)) {
2818 Add a lot of aggravation and time;
2821 Create your own board support subdirectory;
2823 Create your own board config file;
2827 Add / modify source code;
2831 email ("Hi, I am having problems...");
2833 Send patch file to Wolfgang;
2838 void no_more_time (int sig)
2848 All contributions to U-Boot should conform to the Linux kernel
2849 coding style; see the file "Documentation/CodingStyle" in your Linux
2850 kernel source directory.
2852 Please note that U-Boot is implemented in C (and to some small parts
2853 in Assembler); no C++ is used, so please do not use C++ style
2854 comments (//) in your code.
2856 Submissions which do not conform to the standards may be returned
2857 with a request to reformat the changes.
2863 Since the number of patches for U-Boot is growing, we need to
2864 establish some rules. Submissions which do not conform to these rules
2865 may be rejected, even when they contain important and valuable stuff.
2868 When you send a patch, please include the following information with
2871 * For bug fixes: a description of the bug and how your patch fixes
2872 this bug. Please try to include a way of demonstrating that the
2873 patch actually fixes something.
2875 * For new features: a description of the feature and your
2878 * A CHANGELOG entry as plaintext (separate from the patch)
2880 * For major contributions, your entry to the CREDITS file
2882 * When you add support for a new board, don't forget to add this
2883 board to the MAKEALL script, too.
2885 * If your patch adds new configuration options, don't forget to
2886 document these in the README file.
2888 * The patch itself. If you are accessing the CVS repository use "cvs
2889 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
2890 version of diff does not support these options, then get the latest
2891 version of GNU diff.
2893 We accept patches as plain text, MIME attachments or as uuencoded
2898 * Before sending the patch, run the MAKEALL script on your patched
2899 source tree and make sure that no errors or warnings are reported
2900 for any of the boards.
2902 * Keep your modifications to the necessary minimum: A patch
2903 containing several unrelated changes or arbitrary reformats will be
2904 returned with a request to re-formatting / split it.
2906 * If you modify existing code, make sure that your new code does not
2907 add to the memory footprint of the code ;-) Small is beautiful!
2908 When adding new features, these should compile conditionally only
2909 (using #ifdef), and the resulting code with the new feature
2910 disabled must not need more memory than the old code without your
projects / platform / kernel / u-boot.git / blob