2 # (C) Copyright 2000 - 2004
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 dependent files
123 - common Misc architecture independent functions
124 - cpu CPU specific files
125 - 74xx_7xx Files specific to Motorola MPC74xx and 7xx CPUs
126 - arm720t Files specific to ARM 720 CPUs
127 - arm920t Files specific to ARM 920 CPUs
128 - arm925t Files specific to ARM 925 CPUs
129 - arm926ejs Files specific to ARM 926 CPUs
130 - at91rm9200 Files specific to Atmel AT91RM9200 CPUs
131 - i386 Files specific to i386 CPUs
132 - ixp Files specific to Intel XScale IXP CPUs
133 - mcf52x2 Files specific to Motorola ColdFire MCF52x2 CPUs
134 - mips Files specific to MIPS CPUs
135 - mpc5xx Files specific to Motorola MPC5xx CPUs
136 - mpc5xxx Files specific to Motorola MPC5xxx CPUs
137 - mpc8xx Files specific to Motorola MPC8xx CPUs
138 - mpc824x Files specific to Motorola MPC824x CPUs
139 - mpc8260 Files specific to Motorola MPC8260 CPUs
140 - mpc85xx Files specific to Motorola MPC85xx CPUs
141 - nios Files specific to Altera NIOS CPUs
142 - ppc4xx Files specific to IBM PowerPC 4xx CPUs
143 - pxa Files specific to Intel XScale PXA CPUs
144 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
145 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
146 - disk Code for disk drive partition handling
147 - doc Documentation (don't expect too much)
148 - drivers Commonly used device drivers
149 - dtt Digital Thermometer and Thermostat drivers
150 - examples Example code for standalone applications, etc.
151 - include Header Files
152 - lib_arm Files generic to ARM architecture
153 - lib_generic Files generic to all architectures
154 - lib_i386 Files generic to i386 architecture
155 - lib_m68k Files generic to m68k architecture
156 - lib_mips Files generic to MIPS architecture
157 - lib_nios Files generic to NIOS architecture
158 - lib_ppc Files generic to PowerPC architecture
159 - net Networking code
160 - post Power On Self Test
161 - rtc Real Time Clock drivers
162 - tools Tools to build S-Record or U-Boot images, etc.
164 Software Configuration:
165 =======================
167 Configuration is usually done using C preprocessor defines; the
168 rationale behind that is to avoid dead code whenever possible.
170 There are two classes of configuration variables:
172 * Configuration _OPTIONS_:
173 These are selectable by the user and have names beginning with
176 * Configuration _SETTINGS_:
177 These depend on the hardware etc. and should not be meddled with if
178 you don't know what you're doing; they have names beginning with
181 Later we will add a configuration tool - probably similar to or even
182 identical to what's used for the Linux kernel. Right now, we have to
183 do the configuration by hand, which means creating some symbolic
184 links and editing some configuration files. We use the TQM8xxL boards
188 Selection of Processor Architecture and Board Type:
189 ---------------------------------------------------
191 For all supported boards there are ready-to-use default
192 configurations available; just type "make <board_name>_config".
194 Example: For a TQM823L module type:
199 For the Cogent platform, you need to specify the cpu type as well;
200 e.g. "make cogent_mpc8xx_config". And also configure the cogent
201 directory according to the instructions in cogent/README.
204 Configuration Options:
205 ----------------------
207 Configuration depends on the combination of board and CPU type; all
208 such information is kept in a configuration file
209 "include/configs/<board_name>.h".
211 Example: For a TQM823L module, all configuration settings are in
212 "include/configs/TQM823L.h".
215 Many of the options are named exactly as the corresponding Linux
216 kernel configuration options. The intention is to make it easier to
217 build a config tool - later.
220 The following options need to be configured:
222 - CPU Type: Define exactly one of
226 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
228 or CONFIG_MPC824X, CONFIG_MPC8260
244 - Board Type: Define exactly one of
246 PowerPC based boards:
247 ---------------------
249 CONFIG_ADCIOP, CONFIG_ICU862 CONFIG_RPXsuper,
250 CONFIG_ADS860, CONFIG_IP860, CONFIG_SM850,
251 CONFIG_AMX860, CONFIG_IPHASE4539, CONFIG_SPD823TS,
252 CONFIG_AR405, CONFIG_IVML24, CONFIG_SXNI855T,
253 CONFIG_BAB7xx, CONFIG_IVML24_128, CONFIG_Sandpoint8240,
254 CONFIG_CANBT, CONFIG_IVML24_256, CONFIG_Sandpoint8245,
255 CONFIG_CCM, CONFIG_IVMS8, CONFIG_TQM823L,
256 CONFIG_CPCI405, CONFIG_IVMS8_128, CONFIG_TQM850L,
257 CONFIG_CPCI4052, CONFIG_IVMS8_256, CONFIG_TQM855L,
258 CONFIG_CPCIISER4, CONFIG_LANTEC, CONFIG_TQM860L,
259 CONFIG_CPU86, CONFIG_MBX, CONFIG_TQM8260,
260 CONFIG_CRAYL1, CONFIG_MBX860T, CONFIG_TTTech,
261 CONFIG_CU824, CONFIG_MHPC, CONFIG_UTX8245,
262 CONFIG_DASA_SIM, CONFIG_MIP405, CONFIG_W7OLMC,
263 CONFIG_DU405, CONFIG_MOUSSE, CONFIG_W7OLMG,
264 CONFIG_ELPPC, CONFIG_MPC8260ADS, CONFIG_WALNUT405,
265 CONFIG_ERIC, CONFIG_MUSENKI, CONFIG_ZUMA,
266 CONFIG_ESTEEM192E, CONFIG_MVS1, CONFIG_c2mon,
267 CONFIG_ETX094, CONFIG_NX823, CONFIG_cogent_mpc8260,
268 CONFIG_EVB64260, CONFIG_OCRTC, CONFIG_cogent_mpc8xx,
269 CONFIG_FADS823, CONFIG_ORSG, CONFIG_ep8260,
270 CONFIG_FADS850SAR, CONFIG_OXC, CONFIG_gw8260,
271 CONFIG_FADS860T, CONFIG_PCI405, CONFIG_hermes,
272 CONFIG_FLAGADM, CONFIG_PCIPPC2, CONFIG_hymod,
273 CONFIG_FPS850L, CONFIG_PCIPPC6, CONFIG_lwmon,
274 CONFIG_GEN860T, CONFIG_PIP405, CONFIG_pcu_e,
275 CONFIG_GENIETV, CONFIG_PM826, CONFIG_ppmc8260,
276 CONFIG_GTH, CONFIG_RPXClassic, CONFIG_rsdproto,
277 CONFIG_IAD210, CONFIG_RPXlite, CONFIG_sbc8260,
278 CONFIG_EBONY, CONFIG_sacsng, CONFIG_FPS860L,
279 CONFIG_V37, CONFIG_ELPT860, CONFIG_CMI,
280 CONFIG_NETVIA, CONFIG_RBC823, CONFIG_ZPC1900,
281 CONFIG_MPC8540ADS, CONFIG_MPC8560ADS, CONFIG_QS850,
282 CONFIG_QS823, CONFIG_QS860T, CONFIG_DB64360,
283 CONFIG_DB64460, CONFIG_DUET_ADS
288 CONFIG_HHP_CRADLE, CONFIG_DNP1110, CONFIG_EP7312,
289 CONFIG_IMPA7, CONFIG_LART, CONFIG_LUBBOCK,
290 CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
291 CONFIG_H2_OMAP1610, CONFIG_SHANNON, CONFIG_SMDK2400,
292 CONFIG_SMDK2410, CONFIG_TRAB, CONFIG_VCMA9,
296 - CPU Module Type: (if CONFIG_COGENT is defined)
297 Define exactly one of
299 --- FIXME --- not tested yet:
300 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
301 CONFIG_CMA287_23, CONFIG_CMA287_50
303 - Motherboard Type: (if CONFIG_COGENT is defined)
304 Define exactly one of
305 CONFIG_CMA101, CONFIG_CMA102
307 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
308 Define one or more of
311 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
312 Define one or more of
313 CONFIG_LCD_HEARTBEAT - update a character position on
314 the lcd display every second with
317 - Board flavour: (if CONFIG_MPC8260ADS is defined)
320 CFG_8260ADS - original MPC8260ADS
321 CFG_8266ADS - MPC8266ADS
322 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
325 - MPC824X Family Member (if CONFIG_MPC824X is defined)
326 Define exactly one of
327 CONFIG_MPC8240, CONFIG_MPC8245
329 - 8xx CPU Options: (if using an MPC8xx cpu)
330 Define one or more of
331 CONFIG_8xx_GCLK_FREQ - if get_gclk_freq() cannot work
332 e.g. if there is no 32KHz
333 reference PIT/RTC clock
335 - 859/866 CPU options: (if using a MPC859 or MPC866 CPU):
339 CFG_866_CPUCLK_DEFAULT
340 See doc/README.MPC866
344 Define this to measure the actual CPU clock instead
345 of relying on the correctness of the configured
346 values. Mostly useful for board bringup to make sure
347 the PLL is locked at the intended frequency. Note
348 that this requires a (stable) reference clock (32 kHz
351 - Linux Kernel Interface:
354 U-Boot stores all clock information in Hz
355 internally. For binary compatibility with older Linux
356 kernels (which expect the clocks passed in the
357 bd_info data to be in MHz) the environment variable
358 "clocks_in_mhz" can be defined so that U-Boot
359 converts clock data to MHZ before passing it to the
361 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
362 "clocks_in_mhz=1" is automatically included in the
365 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
367 When transfering memsize parameter to linux, some versions
368 expect it to be in bytes, others in MB.
369 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
372 Depending on board, define exactly one serial port
373 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
374 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
375 console by defining CONFIG_8xx_CONS_NONE
377 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
378 port routines must be defined elsewhere
379 (i.e. serial_init(), serial_getc(), ...)
382 Enables console device for a color framebuffer. Needs following
383 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
384 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
386 VIDEO_HW_RECTFILL graphic chip supports
389 VIDEO_HW_BITBLT graphic chip supports
390 bit-blit (cf. smiLynxEM)
391 VIDEO_VISIBLE_COLS visible pixel columns
393 VIDEO_VISIBLE_ROWS visible pixel rows
394 VIDEO_PIXEL_SIZE bytes per pixel
395 VIDEO_DATA_FORMAT graphic data format
396 (0-5, cf. cfb_console.c)
397 VIDEO_FB_ADRS framebuffer address
398 VIDEO_KBD_INIT_FCT keyboard int fct
399 (i.e. i8042_kbd_init())
400 VIDEO_TSTC_FCT test char fct
402 VIDEO_GETC_FCT get char fct
404 CONFIG_CONSOLE_CURSOR cursor drawing on/off
405 (requires blink timer
407 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
408 CONFIG_CONSOLE_TIME display time/date info in
410 (requires CFG_CMD_DATE)
411 CONFIG_VIDEO_LOGO display Linux logo in
413 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
414 linux_logo.h for logo.
415 Requires CONFIG_VIDEO_LOGO
416 CONFIG_CONSOLE_EXTRA_INFO
417 addional board info beside
420 When CONFIG_CFB_CONSOLE is defined, video console is
421 default i/o. Serial console can be forced with
422 environment 'console=serial'.
424 When CONFIG_SILENT_CONSOLE is defined, all console
425 messages (by U-Boot and Linux!) can be silenced with
426 the "silent" environment variable. See
427 doc/README.silent for more information.
430 CONFIG_BAUDRATE - in bps
431 Select one of the baudrates listed in
432 CFG_BAUDRATE_TABLE, see below.
433 CFG_BRGCLK_PRESCALE, baudrate prescale
435 - Interrupt driven serial port input:
436 CONFIG_SERIAL_SOFTWARE_FIFO
439 Use an interrupt handler for receiving data on the
440 serial port. It also enables using hardware handshake
441 (RTS/CTS) and UART's built-in FIFO. Set the number of
442 bytes the interrupt driven input buffer should have.
444 Set to 0 to disable this feature (this is the default).
445 This will also disable hardware handshake.
447 - Console UART Number:
451 If defined internal UART1 (and not UART0) is used
452 as default U-Boot console.
454 - Boot Delay: CONFIG_BOOTDELAY - in seconds
455 Delay before automatically booting the default image;
456 set to -1 to disable autoboot.
458 See doc/README.autoboot for these options that
459 work with CONFIG_BOOTDELAY. None are required.
460 CONFIG_BOOT_RETRY_TIME
461 CONFIG_BOOT_RETRY_MIN
462 CONFIG_AUTOBOOT_KEYED
463 CONFIG_AUTOBOOT_PROMPT
464 CONFIG_AUTOBOOT_DELAY_STR
465 CONFIG_AUTOBOOT_STOP_STR
466 CONFIG_AUTOBOOT_DELAY_STR2
467 CONFIG_AUTOBOOT_STOP_STR2
468 CONFIG_ZERO_BOOTDELAY_CHECK
469 CONFIG_RESET_TO_RETRY
473 Only needed when CONFIG_BOOTDELAY is enabled;
474 define a command string that is automatically executed
475 when no character is read on the console interface
476 within "Boot Delay" after reset.
479 This can be used to pass arguments to the bootm
480 command. The value of CONFIG_BOOTARGS goes into the
481 environment value "bootargs".
483 CONFIG_RAMBOOT and CONFIG_NFSBOOT
484 The value of these goes into the environment as
485 "ramboot" and "nfsboot" respectively, and can be used
486 as a convenience, when switching between booting from
492 When this option is #defined, the existence of the
493 environment variable "preboot" will be checked
494 immediately before starting the CONFIG_BOOTDELAY
495 countdown and/or running the auto-boot command resp.
496 entering interactive mode.
498 This feature is especially useful when "preboot" is
499 automatically generated or modified. For an example
500 see the LWMON board specific code: here "preboot" is
501 modified when the user holds down a certain
502 combination of keys on the (special) keyboard when
505 - Serial Download Echo Mode:
507 If defined to 1, all characters received during a
508 serial download (using the "loads" command) are
509 echoed back. This might be needed by some terminal
510 emulations (like "cu"), but may as well just take
511 time on others. This setting #define's the initial
512 value of the "loads_echo" environment variable.
514 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
516 Select one of the baudrates listed in
517 CFG_BAUDRATE_TABLE, see below.
521 Most monitor functions can be selected (or
522 de-selected) by adjusting the definition of
523 CONFIG_COMMANDS; to select individual functions,
524 #define CONFIG_COMMANDS by "OR"ing any of the
527 #define enables commands:
528 -------------------------
529 CFG_CMD_ASKENV * ask for env variable
530 CFG_CMD_AUTOSCRIPT Autoscript Support
532 CFG_CMD_BEDBUG Include BedBug Debugger
533 CFG_CMD_BMP * BMP support
535 CFG_CMD_CACHE icache, dcache
536 CFG_CMD_CONSOLE coninfo
537 CFG_CMD_DATE * support for RTC, date/time...
538 CFG_CMD_DHCP DHCP support
539 CFG_CMD_DIAG * Diagnostics
540 CFG_CMD_DOC * Disk-On-Chip Support
541 CFG_CMD_DTT Digital Therm and Thermostat
542 CFG_CMD_ECHO * echo arguments
543 CFG_CMD_EEPROM * EEPROM read/write support
544 CFG_CMD_ELF bootelf, bootvx
546 CFG_CMD_FDC * Floppy Disk Support
547 CFG_CMD_FAT FAT partition support
548 CFG_CMD_FDOS * Dos diskette Support
549 CFG_CMD_FLASH flinfo, erase, protect
550 CFG_CMD_FPGA FPGA device initialization support
551 CFG_CMD_HWFLOW * RTS/CTS hw flow control
552 CFG_CMD_I2C * I2C serial bus support
553 CFG_CMD_IDE * IDE harddisk support
555 CFG_CMD_IMLS List all found images
556 CFG_CMD_IMMAP * IMMR dump support
557 CFG_CMD_IRQ * irqinfo
558 CFG_CMD_ITEST * Integer/string test of 2 values
559 CFG_CMD_JFFS2 * JFFS2 Support
563 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
565 CFG_CMD_MISC Misc functions like sleep etc
566 CFG_CMD_MMC MMC memory mapped support
567 CFG_CMD_MII MII utility commands
568 CFG_CMD_NAND * NAND support
569 CFG_CMD_NET bootp, tftpboot, rarpboot
570 CFG_CMD_PCI * pciinfo
571 CFG_CMD_PCMCIA * PCMCIA support
572 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
573 CFG_CMD_PORTIO * Port I/O
574 CFG_CMD_REGINFO * Register dump
575 CFG_CMD_RUN run command in env variable
576 CFG_CMD_SAVES save S record dump
577 CFG_CMD_SCSI * SCSI Support
578 CFG_CMD_SDRAM * print SDRAM configuration information
579 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
580 CFG_CMD_SPI * SPI serial bus support
581 CFG_CMD_USB * USB support
582 CFG_CMD_VFD * VFD support (TRAB)
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 be 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_DS1338 - use Maxim, Inc. DS1338 RTC
642 CONFIG_RTC_DS164x - use Dallas DS164x RTC
644 Note that if the RTC uses I2C, then the I2C interface
645 must also be configured. See I2C Support, below.
649 When CONFIG_TIMESTAMP is selected, the timestamp
650 (date and time) of an image is printed by image
651 commands like bootm or iminfo. This option is
652 automatically enabled when you select CFG_CMD_DATE .
655 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
656 and/or CONFIG_ISO_PARTITION
658 If IDE or SCSI support is enabled (CFG_CMD_IDE or
659 CFG_CMD_SCSI) you must configure support for at least
660 one partition type as well.
663 CONFIG_IDE_RESET_ROUTINE - this is defined in several
664 board configurations files but used nowhere!
666 CONFIG_IDE_RESET - is this is defined, IDE Reset will
667 be performed by calling the function
668 ide_set_reset(int reset)
669 which has to be defined in a board specific file
674 Set this to enable ATAPI support.
679 Set this to enable support for disks larger than 137GB
680 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
681 Whithout these , LBA48 support uses 32bit variables and will 'only'
682 support disks up to 2.1TB.
685 When enabled, makes the IDE subsystem use 64bit sector addresses.
689 At the moment only there is only support for the
690 SYM53C8XX SCSI controller; define
691 CONFIG_SCSI_SYM53C8XX to enable it.
693 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
694 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
695 CFG_SCSI_MAX_LUN] can be adjusted to define the
696 maximum numbers of LUNs, SCSI ID's and target
698 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
700 - NETWORK Support (PCI):
702 Support for Intel 8254x gigabit chips.
705 Support for Intel 82557/82559/82559ER chips.
706 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
707 write routine for first time initialisation.
710 Support for Digital 2114x chips.
711 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
712 modem chip initialisation (KS8761/QS6611).
715 Support for National dp83815 chips.
718 Support for National dp8382[01] gigabit chips.
720 - NETWORK Support (other):
722 CONFIG_DRIVER_LAN91C96
723 Support for SMSC's LAN91C96 chips.
726 Define this to hold the physical address
727 of the LAN91C96's I/O space
729 CONFIG_LAN91C96_USE_32_BIT
730 Define this to enable 32 bit addressing
733 At the moment only the UHCI host controller is
734 supported (PIP405, MIP405, MPC5200); define
735 CONFIG_USB_UHCI to enable it.
736 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
737 end define CONFIG_USB_STORAGE to enable the USB
740 Supported are USB Keyboards and USB Floppy drives
742 MPC5200 USB requires additional defines:
744 for 528 MHz Clock: 0x0001bbbb
746 for differential drivers: 0x00001000
747 for single ended drivers: 0x00005000
751 The MMC controller on the Intel PXA is supported. To
752 enable this define CONFIG_MMC. The MMC can be
753 accessed from the boot prompt by mapping the device
754 to physical memory similar to flash. Command line is
755 enabled with CFG_CMD_MMC. The MMC driver also works with
756 the FAT fs. This is enabled with CFG_CMD_FAT.
761 Define this to enable standard (PC-Style) keyboard
765 Standard PC keyboard driver with US (is default) and
766 GERMAN key layout (switch via environment 'keymap=de') support.
767 Export function i8042_kbd_init, i8042_tstc and i8042_getc
768 for cfb_console. Supports cursor blinking.
773 Define this to enable video support (for output to
778 Enable Chips & Technologies 69000 Video chip
780 CONFIG_VIDEO_SMI_LYNXEM
781 Enable Silicon Motion SMI 712/710/810 Video chip
782 Videomode are selected via environment 'videomode' with
783 standard LiLo mode numbers.
784 Following modes are supported (* is default):
786 800x600 1024x768 1280x1024
787 256 (8bit) 303* 305 307
788 65536 (16bit) 314 317 31a
789 16,7 Mill (24bit) 315 318 31b
790 (i.e. setenv videomode 317; saveenv; reset;)
792 CONFIG_VIDEO_SED13806
793 Enable Epson SED13806 driver. This driver supports 8bpp
794 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
795 or CONFIG_VIDEO_SED13806_16BPP
800 Define this to enable a custom keyboard support.
801 This simply calls drv_keyboard_init() which must be
802 defined in your board-specific files.
803 The only board using this so far is RBC823.
805 - LCD Support: CONFIG_LCD
807 Define this to enable LCD support (for output to LCD
808 display); also select one of the supported displays
809 by defining one of these:
811 CONFIG_NEC_NL6448AC33:
813 NEC NL6448AC33-18. Active, color, single scan.
815 CONFIG_NEC_NL6448BC20
817 NEC NL6448BC20-08. 6.5", 640x480.
818 Active, color, single scan.
820 CONFIG_NEC_NL6448BC33_54
822 NEC NL6448BC33-54. 10.4", 640x480.
823 Active, color, single scan.
827 Sharp 320x240. Active, color, single scan.
828 It isn't 16x9, and I am not sure what it is.
830 CONFIG_SHARP_LQ64D341
832 Sharp LQ64D341 display, 640x480.
833 Active, color, single scan.
837 HLD1045 display, 640x480.
838 Active, color, single scan.
842 Optrex CBL50840-2 NF-FW 99 22 M5
844 Hitachi LMG6912RPFC-00T
848 320x240. Black & white.
850 Normally display is black on white background; define
851 CFG_WHITE_ON_BLACK to get it inverted.
853 - Splash Screen Support: CONFIG_SPLASH_SCREEN
855 If this option is set, the environment is checked for
856 a variable "splashimage". If found, the usual display
857 of logo, copyright and system information on the LCD
858 is supressed and the BMP image at the address
859 specified in "splashimage" is loaded instead. The
860 console is redirected to the "nulldev", too. This
861 allows for a "silent" boot where a splash screen is
862 loaded very quickly after power-on.
864 - Compression support:
867 If this option is set, support for bzip2 compressed
868 images is included. If not, only uncompressed and gzip
869 compressed images are supported.
871 NOTE: the bzip2 algorithm requires a lot of RAM, so
872 the malloc area (as defined by CFG_MALLOC_LEN) should
880 Define a default value for ethernet address to use
881 for the respective ethernet interface, in case this
882 is not determined automatically.
887 Define a default value for the IP address to use for
888 the default ethernet interface, in case this is not
889 determined through e.g. bootp.
894 Defines a default value for theIP address of a TFTP
895 server to contact when using the "tftboot" command.
897 - BOOTP Recovery Mode:
898 CONFIG_BOOTP_RANDOM_DELAY
900 If you have many targets in a network that try to
901 boot using BOOTP, you may want to avoid that all
902 systems send out BOOTP requests at precisely the same
903 moment (which would happen for instance at recovery
904 from a power failure, when all systems will try to
905 boot, thus flooding the BOOTP server. Defining
906 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
907 inserted before sending out BOOTP requests. The
908 following delays are insterted then:
910 1st BOOTP request: delay 0 ... 1 sec
911 2nd BOOTP request: delay 0 ... 2 sec
912 3rd BOOTP request: delay 0 ... 4 sec
914 BOOTP requests: delay 0 ... 8 sec
916 - DHCP Advanced Options:
919 You can fine tune the DHCP functionality by adding
920 these flags to the CONFIG_BOOTP_MASK define:
922 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
923 serverip from a DHCP server, it is possible that more
924 than one DNS serverip is offered to the client.
925 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
926 serverip will be stored in the additional environment
927 variable "dnsip2". The first DNS serverip is always
928 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
929 is added to the CONFIG_BOOTP_MASK.
931 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
932 to do a dynamic update of a DNS server. To do this, they
933 need the hostname of the DHCP requester.
934 If CONFIG_BOOP_SEND_HOSTNAME is added to the
935 CONFIG_BOOTP_MASK, the content of the "hostname"
936 environment variable is passed as option 12 to
939 - Status LED: CONFIG_STATUS_LED
941 Several configurations allow to display the current
942 status using a LED. For instance, the LED will blink
943 fast while running U-Boot code, stop blinking as
944 soon as a reply to a BOOTP request was received, and
945 start blinking slow once the Linux kernel is running
946 (supported by a status LED driver in the Linux
947 kernel). Defining CONFIG_STATUS_LED enables this
950 - CAN Support: CONFIG_CAN_DRIVER
952 Defining CONFIG_CAN_DRIVER enables CAN driver support
953 on those systems that support this (optional)
954 feature, like the TQM8xxL modules.
956 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
958 These enable I2C serial bus commands. Defining either of
959 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
960 include the appropriate I2C driver for the selected cpu.
962 This will allow you to use i2c commands at the u-boot
963 command line (as long as you set CFG_CMD_I2C in
964 CONFIG_COMMANDS) and communicate with i2c based realtime
965 clock chips. See common/cmd_i2c.c for a description of the
966 command line interface.
968 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
970 CONFIG_SOFT_I2C configures u-boot to use a software (aka
971 bit-banging) driver instead of CPM or similar hardware
974 There are several other quantities that must also be
975 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
977 In both cases you will need to define CFG_I2C_SPEED
978 to be the frequency (in Hz) at which you wish your i2c bus
979 to run and CFG_I2C_SLAVE to be the address of this node (ie
980 the cpu's i2c node address).
982 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
983 sets the cpu up as a master node and so its address should
984 therefore be cleared to 0 (See, eg, MPC823e User's Manual
985 p.16-473). So, set CFG_I2C_SLAVE to 0.
987 That's all that's required for CONFIG_HARD_I2C.
989 If you use the software i2c interface (CONFIG_SOFT_I2C)
990 then the following macros need to be defined (examples are
991 from include/configs/lwmon.h):
995 (Optional). Any commands necessary to enable the I2C
996 controller or configure ports.
998 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1002 (Only for MPC8260 CPU). The I/O port to use (the code
1003 assumes both bits are on the same port). Valid values
1004 are 0..3 for ports A..D.
1008 The code necessary to make the I2C data line active
1009 (driven). If the data line is open collector, this
1012 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1016 The code necessary to make the I2C data line tri-stated
1017 (inactive). If the data line is open collector, this
1020 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1024 Code that returns TRUE if the I2C data line is high,
1027 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1031 If <bit> is TRUE, sets the I2C data line high. If it
1032 is FALSE, it clears it (low).
1034 eg: #define I2C_SDA(bit) \
1035 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1036 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1040 If <bit> is TRUE, sets the I2C clock line high. If it
1041 is FALSE, it clears it (low).
1043 eg: #define I2C_SCL(bit) \
1044 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1045 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1049 This delay is invoked four times per clock cycle so this
1050 controls the rate of data transfer. The data rate thus
1051 is 1 / (I2C_DELAY * 4). Often defined to be something
1054 #define I2C_DELAY udelay(2)
1058 When a board is reset during an i2c bus transfer
1059 chips might think that the current transfer is still
1060 in progress. On some boards it is possible to access
1061 the i2c SCLK line directly, either by using the
1062 processor pin as a GPIO or by having a second pin
1063 connected to the bus. If this option is defined a
1064 custom i2c_init_board() routine in boards/xxx/board.c
1065 is run early in the boot sequence.
1067 - SPI Support: CONFIG_SPI
1069 Enables SPI driver (so far only tested with
1070 SPI EEPROM, also an instance works with Crystal A/D and
1071 D/As on the SACSng board)
1075 Enables extended (16-bit) SPI EEPROM addressing.
1076 (symmetrical to CONFIG_I2C_X)
1080 Enables a software (bit-bang) SPI driver rather than
1081 using hardware support. This is a general purpose
1082 driver that only requires three general I/O port pins
1083 (two outputs, one input) to function. If this is
1084 defined, the board configuration must define several
1085 SPI configuration items (port pins to use, etc). For
1086 an example, see include/configs/sacsng.h.
1088 - FPGA Support: CONFIG_FPGA_COUNT
1090 Specify the number of FPGA devices to support.
1094 Used to specify the types of FPGA devices. For example,
1095 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1097 CFG_FPGA_PROG_FEEDBACK
1099 Enable printing of hash marks during FPGA configuration.
1103 Enable checks on FPGA configuration interface busy
1104 status by the configuration function. This option
1105 will require a board or device specific function to
1110 If defined, a function that provides delays in the FPGA
1111 configuration driver.
1113 CFG_FPGA_CHECK_CTRLC
1114 Allow Control-C to interrupt FPGA configuration
1116 CFG_FPGA_CHECK_ERROR
1118 Check for configuration errors during FPGA bitfile
1119 loading. For example, abort during Virtex II
1120 configuration if the INIT_B line goes low (which
1121 indicated a CRC error).
1125 Maximum time to wait for the INIT_B line to deassert
1126 after PROB_B has been deasserted during a Virtex II
1127 FPGA configuration sequence. The default time is 500
1132 Maximum time to wait for BUSY to deassert during
1133 Virtex II FPGA configuration. The default is 5 mS.
1135 CFG_FPGA_WAIT_CONFIG
1137 Time to wait after FPGA configuration. The default is
1140 - Configuration Management:
1143 If defined, this string will be added to the U-Boot
1144 version information (U_BOOT_VERSION)
1146 - Vendor Parameter Protection:
1148 U-Boot considers the values of the environment
1149 variables "serial#" (Board Serial Number) and
1150 "ethaddr" (Ethernet Address) to be parameters that
1151 are set once by the board vendor / manufacturer, and
1152 protects these variables from casual modification by
1153 the user. Once set, these variables are read-only,
1154 and write or delete attempts are rejected. You can
1155 change this behviour:
1157 If CONFIG_ENV_OVERWRITE is #defined in your config
1158 file, the write protection for vendor parameters is
1159 completely disabled. Anybody can change or delete
1162 Alternatively, if you #define _both_ CONFIG_ETHADDR
1163 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1164 ethernet address is installed in the environment,
1165 which can be changed exactly ONCE by the user. [The
1166 serial# is unaffected by this, i. e. it remains
1172 Define this variable to enable the reservation of
1173 "protected RAM", i. e. RAM which is not overwritten
1174 by U-Boot. Define CONFIG_PRAM to hold the number of
1175 kB you want to reserve for pRAM. You can overwrite
1176 this default value by defining an environment
1177 variable "pram" to the number of kB you want to
1178 reserve. Note that the board info structure will
1179 still show the full amount of RAM. If pRAM is
1180 reserved, a new environment variable "mem" will
1181 automatically be defined to hold the amount of
1182 remaining RAM in a form that can be passed as boot
1183 argument to Linux, for instance like that:
1185 setenv bootargs ... mem=\$(mem)
1188 This way you can tell Linux not to use this memory,
1189 either, which results in a memory region that will
1190 not be affected by reboots.
1192 *WARNING* If your board configuration uses automatic
1193 detection of the RAM size, you must make sure that
1194 this memory test is non-destructive. So far, the
1195 following board configurations are known to be
1198 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1199 HERMES, IP860, RPXlite, LWMON, LANTEC,
1200 PCU_E, FLAGADM, TQM8260
1205 Define this variable to stop the system in case of a
1206 fatal error, so that you have to reset it manually.
1207 This is probably NOT a good idea for an embedded
1208 system where you want to system to reboot
1209 automatically as fast as possible, but it may be
1210 useful during development since you can try to debug
1211 the conditions that lead to the situation.
1213 CONFIG_NET_RETRY_COUNT
1215 This variable defines the number of retries for
1216 network operations like ARP, RARP, TFTP, or BOOTP
1217 before giving up the operation. If not defined, a
1218 default value of 5 is used.
1220 - Command Interpreter:
1223 Define this variable to enable the "hush" shell (from
1224 Busybox) as command line interpreter, thus enabling
1225 powerful command line syntax like
1226 if...then...else...fi conditionals or `&&' and '||'
1227 constructs ("shell scripts").
1229 If undefined, you get the old, much simpler behaviour
1230 with a somewhat smaller memory footprint.
1235 This defines the secondary prompt string, which is
1236 printed when the command interpreter needs more input
1237 to complete a command. Usually "> ".
1241 In the current implementation, the local variables
1242 space and global environment variables space are
1243 separated. Local variables are those you define by
1244 simply typing `name=value'. To access a local
1245 variable later on, you have write `$name' or
1246 `${name}'; to execute the contents of a variable
1247 directly type `$name' at the command prompt.
1249 Global environment variables are those you use
1250 setenv/printenv to work with. To run a command stored
1251 in such a variable, you need to use the run command,
1252 and you must not use the '$' sign to access them.
1254 To store commands and special characters in a
1255 variable, please use double quotation marks
1256 surrounding the whole text of the variable, instead
1257 of the backslashes before semicolons and special
1260 - Default Environment:
1261 CONFIG_EXTRA_ENV_SETTINGS
1263 Define this to contain any number of null terminated
1264 strings (variable = value pairs) that will be part of
1265 the default environment compiled into the boot image.
1267 For example, place something like this in your
1268 board's config file:
1270 #define CONFIG_EXTRA_ENV_SETTINGS \
1274 Warning: This method is based on knowledge about the
1275 internal format how the environment is stored by the
1276 U-Boot code. This is NOT an official, exported
1277 interface! Although it is unlikely that this format
1278 will change soon, there is no guarantee either.
1279 You better know what you are doing here.
1281 Note: overly (ab)use of the default environment is
1282 discouraged. Make sure to check other ways to preset
1283 the environment like the autoscript function or the
1286 - DataFlash Support:
1287 CONFIG_HAS_DATAFLASH
1289 Defining this option enables DataFlash features and
1290 allows to read/write in Dataflash via the standard
1293 - SystemACE Support:
1296 Adding this option adds support for Xilinx SystemACE
1297 chips attached via some sort of local bus. The address
1298 of the chip must alsh be defined in the
1299 CFG_SYSTEMACE_BASE macro. For example:
1301 #define CONFIG_SYSTEMACE
1302 #define CFG_SYSTEMACE_BASE 0xf0000000
1304 When SystemACE support is added, the "ace" device type
1305 becomes available to the fat commands, i.e. fatls.
1307 - Show boot progress:
1308 CONFIG_SHOW_BOOT_PROGRESS
1310 Defining this option allows to add some board-
1311 specific code (calling a user-provided function
1312 "show_boot_progress(int)") that enables you to show
1313 the system's boot progress on some display (for
1314 example, some LED's) on your board. At the moment,
1315 the following checkpoints are implemented:
1318 1 common/cmd_bootm.c before attempting to boot an image
1319 -1 common/cmd_bootm.c Image header has bad magic number
1320 2 common/cmd_bootm.c Image header has correct magic number
1321 -2 common/cmd_bootm.c Image header has bad checksum
1322 3 common/cmd_bootm.c Image header has correct checksum
1323 -3 common/cmd_bootm.c Image data has bad checksum
1324 4 common/cmd_bootm.c Image data has correct checksum
1325 -4 common/cmd_bootm.c Image is for unsupported architecture
1326 5 common/cmd_bootm.c Architecture check OK
1327 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1328 6 common/cmd_bootm.c Image Type check OK
1329 -6 common/cmd_bootm.c gunzip uncompression error
1330 -7 common/cmd_bootm.c Unimplemented compression type
1331 7 common/cmd_bootm.c Uncompression OK
1332 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1333 8 common/cmd_bootm.c Image Type check OK
1334 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1335 9 common/cmd_bootm.c Start initial ramdisk verification
1336 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1337 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1338 10 common/cmd_bootm.c Ramdisk header is OK
1339 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1340 11 common/cmd_bootm.c Ramdisk data has correct checksum
1341 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1342 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1343 13 common/cmd_bootm.c Start multifile image verification
1344 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1345 15 common/cmd_bootm.c All preparation done, transferring control to OS
1347 -30 lib_ppc/board.c Fatal error, hang the system
1348 -31 post/post.c POST test failed, detected by post_output_backlog()
1349 -32 post/post.c POST test failed, detected by post_run_single()
1351 -1 common/cmd_doc.c Bad usage of "doc" command
1352 -1 common/cmd_doc.c No boot device
1353 -1 common/cmd_doc.c Unknown Chip ID on boot device
1354 -1 common/cmd_doc.c Read Error on boot device
1355 -1 common/cmd_doc.c Image header has bad magic number
1357 -1 common/cmd_ide.c Bad usage of "ide" command
1358 -1 common/cmd_ide.c No boot device
1359 -1 common/cmd_ide.c Unknown boot device
1360 -1 common/cmd_ide.c Unknown partition table
1361 -1 common/cmd_ide.c Invalid partition type
1362 -1 common/cmd_ide.c Read Error on boot device
1363 -1 common/cmd_ide.c Image header has bad magic number
1365 -1 common/cmd_nand.c Bad usage of "nand" command
1366 -1 common/cmd_nand.c No boot device
1367 -1 common/cmd_nand.c Unknown Chip ID on boot device
1368 -1 common/cmd_nand.c Read Error on boot device
1369 -1 common/cmd_nand.c Image header has bad magic number
1371 -1 common/env_common.c Environment has a bad CRC, using default
1377 [so far only for SMDK2400 and TRAB boards]
1379 - Modem support endable:
1380 CONFIG_MODEM_SUPPORT
1382 - RTS/CTS Flow control enable:
1385 - Modem debug support:
1386 CONFIG_MODEM_SUPPORT_DEBUG
1388 Enables debugging stuff (char screen[1024], dbg())
1389 for modem support. Useful only with BDI2000.
1391 - Interrupt support (PPC):
1393 There are common interrupt_init() and timer_interrupt()
1394 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1395 for cpu specific initialization. interrupt_init_cpu()
1396 should set decrementer_count to appropriate value. If
1397 cpu resets decrementer automatically after interrupt
1398 (ppc4xx) it should set decrementer_count to zero.
1399 timer_interrupt() calls timer_interrupt_cpu() for cpu
1400 specific handling. If board has watchdog / status_led
1401 / other_activity_monitor it works automatically from
1402 general timer_interrupt().
1406 In the target system modem support is enabled when a
1407 specific key (key combination) is pressed during
1408 power-on. Otherwise U-Boot will boot normally
1409 (autoboot). The key_pressed() fuction is called from
1410 board_init(). Currently key_pressed() is a dummy
1411 function, returning 1 and thus enabling modem
1414 If there are no modem init strings in the
1415 environment, U-Boot proceed to autoboot; the
1416 previous output (banner, info printfs) will be
1419 See also: doc/README.Modem
1422 Configuration Settings:
1423 -----------------------
1425 - CFG_LONGHELP: Defined when you want long help messages included;
1426 undefine this when you're short of memory.
1428 - CFG_PROMPT: This is what U-Boot prints on the console to
1429 prompt for user input.
1431 - CFG_CBSIZE: Buffer size for input from the Console
1433 - CFG_PBSIZE: Buffer size for Console output
1435 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1437 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1438 the application (usually a Linux kernel) when it is
1441 - CFG_BAUDRATE_TABLE:
1442 List of legal baudrate settings for this board.
1444 - CFG_CONSOLE_INFO_QUIET
1445 Suppress display of console information at boot.
1447 - CFG_CONSOLE_IS_IN_ENV
1448 If the board specific function
1449 extern int overwrite_console (void);
1450 returns 1, the stdin, stderr and stdout are switched to the
1451 serial port, else the settings in the environment are used.
1453 - CFG_CONSOLE_OVERWRITE_ROUTINE
1454 Enable the call to overwrite_console().
1456 - CFG_CONSOLE_ENV_OVERWRITE
1457 Enable overwrite of previous console environment settings.
1459 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1460 Begin and End addresses of the area used by the
1464 Enable an alternate, more extensive memory test.
1466 - CFG_MEMTEST_SCRATCH:
1467 Scratch address used by the alternate memory test
1468 You only need to set this if address zero isn't writeable
1470 - CFG_TFTP_LOADADDR:
1471 Default load address for network file downloads
1473 - CFG_LOADS_BAUD_CHANGE:
1474 Enable temporary baudrate change while serial download
1477 Physical start address of SDRAM. _Must_ be 0 here.
1480 Physical start address of Motherboard I/O (if using a
1484 Physical start address of Flash memory.
1487 Physical start address of boot monitor code (set by
1488 make config files to be same as the text base address
1489 (TEXT_BASE) used when linking) - same as
1490 CFG_FLASH_BASE when booting from flash.
1493 Size of memory reserved for monitor code, used to
1494 determine _at_compile_time_ (!) if the environment is
1495 embedded within the U-Boot image, or in a separate
1499 Size of DRAM reserved for malloc() use.
1502 Maximum size of memory mapped by the startup code of
1503 the Linux kernel; all data that must be processed by
1504 the Linux kernel (bd_info, boot arguments, eventually
1505 initrd image) must be put below this limit.
1507 - CFG_MAX_FLASH_BANKS:
1508 Max number of Flash memory banks
1510 - CFG_MAX_FLASH_SECT:
1511 Max number of sectors on a Flash chip
1513 - CFG_FLASH_ERASE_TOUT:
1514 Timeout for Flash erase operations (in ms)
1516 - CFG_FLASH_WRITE_TOUT:
1517 Timeout for Flash write operations (in ms)
1519 - CFG_FLASH_LOCK_TOUT
1520 Timeout for Flash set sector lock bit operation (in ms)
1522 - CFG_FLASH_UNLOCK_TOUT
1523 Timeout for Flash clear lock bits operation (in ms)
1525 - CFG_FLASH_PROTECTION
1526 If defined, hardware flash sectors protection is used
1527 instead of U-Boot software protection.
1529 - CFG_DIRECT_FLASH_TFTP:
1531 Enable TFTP transfers directly to flash memory;
1532 without this option such a download has to be
1533 performed in two steps: (1) download to RAM, and (2)
1534 copy from RAM to flash.
1536 The two-step approach is usually more reliable, since
1537 you can check if the download worked before you erase
1538 the flash, but in some situations (when sytem RAM is
1539 too limited to allow for a tempory copy of the
1540 downloaded image) this option may be very useful.
1543 Define if the flash driver uses extra elements in the
1544 common flash structure for storing flash geometry.
1546 - CFG_FLASH_CFI_DRIVER
1547 This option also enables the building of the cfi_flash driver
1548 in the drivers directory
1550 - CFG_RX_ETH_BUFFER:
1551 Defines the number of ethernet receive buffers. On some
1552 ethernet controllers it is recommended to set this value
1553 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1554 buffers can be full shortly after enabling the interface
1555 on high ethernet traffic.
1556 Defaults to 4 if not defined.
1558 The following definitions that deal with the placement and management
1559 of environment data (variable area); in general, we support the
1560 following configurations:
1562 - CFG_ENV_IS_IN_FLASH:
1564 Define this if the environment is in flash memory.
1566 a) The environment occupies one whole flash sector, which is
1567 "embedded" in the text segment with the U-Boot code. This
1568 happens usually with "bottom boot sector" or "top boot
1569 sector" type flash chips, which have several smaller
1570 sectors at the start or the end. For instance, such a
1571 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1572 such a case you would place the environment in one of the
1573 4 kB sectors - with U-Boot code before and after it. With
1574 "top boot sector" type flash chips, you would put the
1575 environment in one of the last sectors, leaving a gap
1576 between U-Boot and the environment.
1580 Offset of environment data (variable area) to the
1581 beginning of flash memory; for instance, with bottom boot
1582 type flash chips the second sector can be used: the offset
1583 for this sector is given here.
1585 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1589 This is just another way to specify the start address of
1590 the flash sector containing the environment (instead of
1593 - CFG_ENV_SECT_SIZE:
1595 Size of the sector containing the environment.
1598 b) Sometimes flash chips have few, equal sized, BIG sectors.
1599 In such a case you don't want to spend a whole sector for
1604 If you use this in combination with CFG_ENV_IS_IN_FLASH
1605 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1606 of this flash sector for the environment. This saves
1607 memory for the RAM copy of the environment.
1609 It may also save flash memory if you decide to use this
1610 when your environment is "embedded" within U-Boot code,
1611 since then the remainder of the flash sector could be used
1612 for U-Boot code. It should be pointed out that this is
1613 STRONGLY DISCOURAGED from a robustness point of view:
1614 updating the environment in flash makes it always
1615 necessary to erase the WHOLE sector. If something goes
1616 wrong before the contents has been restored from a copy in
1617 RAM, your target system will be dead.
1619 - CFG_ENV_ADDR_REDUND
1622 These settings describe a second storage area used to hold
1623 a redundand copy of the environment data, so that there is
1624 a valid backup copy in case there is a power failure during
1625 a "saveenv" operation.
1627 BE CAREFUL! Any changes to the flash layout, and some changes to the
1628 source code will make it necessary to adapt <board>/u-boot.lds*
1632 - CFG_ENV_IS_IN_NVRAM:
1634 Define this if you have some non-volatile memory device
1635 (NVRAM, battery buffered SRAM) which you want to use for the
1641 These two #defines are used to determin the memory area you
1642 want to use for environment. It is assumed that this memory
1643 can just be read and written to, without any special
1646 BE CAREFUL! The first access to the environment happens quite early
1647 in U-Boot initalization (when we try to get the setting of for the
1648 console baudrate). You *MUST* have mappend your NVRAM area then, or
1651 Please note that even with NVRAM we still use a copy of the
1652 environment in RAM: we could work on NVRAM directly, but we want to
1653 keep settings there always unmodified except somebody uses "saveenv"
1654 to save the current settings.
1657 - CFG_ENV_IS_IN_EEPROM:
1659 Use this if you have an EEPROM or similar serial access
1660 device and a driver for it.
1665 These two #defines specify the offset and size of the
1666 environment area within the total memory of your EEPROM.
1668 - CFG_I2C_EEPROM_ADDR:
1669 If defined, specified the chip address of the EEPROM device.
1670 The default address is zero.
1672 - CFG_EEPROM_PAGE_WRITE_BITS:
1673 If defined, the number of bits used to address bytes in a
1674 single page in the EEPROM device. A 64 byte page, for example
1675 would require six bits.
1677 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1678 If defined, the number of milliseconds to delay between
1679 page writes. The default is zero milliseconds.
1681 - CFG_I2C_EEPROM_ADDR_LEN:
1682 The length in bytes of the EEPROM memory array address. Note
1683 that this is NOT the chip address length!
1686 The size in bytes of the EEPROM device.
1689 - CFG_ENV_IS_IN_DATAFLASH:
1691 Define this if you have a DataFlash memory device which you
1692 want to use for the environment.
1698 These three #defines specify the offset and size of the
1699 environment area within the total memory of your DataFlash placed
1700 at the specified address.
1703 - CFG_SPI_INIT_OFFSET
1705 Defines offset to the initial SPI buffer area in DPRAM. The
1706 area is used at an early stage (ROM part) if the environment
1707 is configured to reside in the SPI EEPROM: We need a 520 byte
1708 scratch DPRAM area. It is used between the two initialization
1709 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1710 to be a good choice since it makes it far enough from the
1711 start of the data area as well as from the stack pointer.
1713 Please note that the environment is read-only as long as the monitor
1714 has been relocated to RAM and a RAM copy of the environment has been
1715 created; also, when using EEPROM you will have to use getenv_r()
1716 until then to read environment variables.
1718 The environment is protected by a CRC32 checksum. Before the monitor
1719 is relocated into RAM, as a result of a bad CRC you will be working
1720 with the compiled-in default environment - *silently*!!! [This is
1721 necessary, because the first environment variable we need is the
1722 "baudrate" setting for the console - if we have a bad CRC, we don't
1723 have any device yet where we could complain.]
1725 Note: once the monitor has been relocated, then it will complain if
1726 the default environment is used; a new CRC is computed as soon as you
1727 use the "saveenv" command to store a valid environment.
1729 - CFG_FAULT_ECHO_LINK_DOWN:
1730 Echo the inverted Ethernet link state to the fault LED.
1732 Note: If this option is active, then CFG_FAULT_MII_ADDR
1733 also needs to be defined.
1735 - CFG_FAULT_MII_ADDR:
1736 MII address of the PHY to check for the Ethernet link state.
1738 - CFG_64BIT_VSPRINTF:
1739 Makes vsprintf (and all *printf functions) support printing
1740 of 64bit values by using the L quantifier
1742 - CFG_64BIT_STRTOUL:
1743 Adds simple_strtoull that returns a 64bit value
1745 Low Level (hardware related) configuration options:
1746 ---------------------------------------------------
1748 - CFG_CACHELINE_SIZE:
1749 Cache Line Size of the CPU.
1752 Default address of the IMMR after system reset.
1754 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1755 and RPXsuper) to be able to adjust the position of
1756 the IMMR register after a reset.
1758 - Floppy Disk Support:
1759 CFG_FDC_DRIVE_NUMBER
1761 the default drive number (default value 0)
1765 defines the spacing between fdc chipset registers
1770 defines the offset of register from address. It
1771 depends on which part of the data bus is connected to
1772 the fdc chipset. (default value 0)
1774 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1775 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1778 if CFG_FDC_HW_INIT is defined, then the function
1779 fdc_hw_init() is called at the beginning of the FDC
1780 setup. fdc_hw_init() must be provided by the board
1781 source code. It is used to make hardware dependant
1784 - CFG_IMMR: Physical address of the Internal Memory Mapped
1785 Register; DO NOT CHANGE! (11-4)
1786 [MPC8xx systems only]
1788 - CFG_INIT_RAM_ADDR:
1790 Start address of memory area that can be used for
1791 initial data and stack; please note that this must be
1792 writable memory that is working WITHOUT special
1793 initialization, i. e. you CANNOT use normal RAM which
1794 will become available only after programming the
1795 memory controller and running certain initialization
1798 U-Boot uses the following memory types:
1799 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1800 - MPC824X: data cache
1801 - PPC4xx: data cache
1803 - CFG_GBL_DATA_OFFSET:
1805 Offset of the initial data structure in the memory
1806 area defined by CFG_INIT_RAM_ADDR. Usually
1807 CFG_GBL_DATA_OFFSET is chosen such that the initial
1808 data is located at the end of the available space
1809 (sometimes written as (CFG_INIT_RAM_END -
1810 CFG_INIT_DATA_SIZE), and the initial stack is just
1811 below that area (growing from (CFG_INIT_RAM_ADDR +
1812 CFG_GBL_DATA_OFFSET) downward.
1815 On the MPC824X (or other systems that use the data
1816 cache for initial memory) the address chosen for
1817 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1818 point to an otherwise UNUSED address space between
1819 the top of RAM and the start of the PCI space.
1821 - CFG_SIUMCR: SIU Module Configuration (11-6)
1823 - CFG_SYPCR: System Protection Control (11-9)
1825 - CFG_TBSCR: Time Base Status and Control (11-26)
1827 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1829 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1831 - CFG_SCCR: System Clock and reset Control Register (15-27)
1833 - CFG_OR_TIMING_SDRAM:
1837 periodic timer for refresh
1839 - CFG_DER: Debug Event Register (37-47)
1841 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1842 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1843 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1845 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1847 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1848 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1849 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1850 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1852 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1853 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1854 Machine Mode Register and Memory Periodic Timer
1855 Prescaler definitions (SDRAM timing)
1857 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1858 enable I2C microcode relocation patch (MPC8xx);
1859 define relocation offset in DPRAM [DSP2]
1861 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1862 enable SPI microcode relocation patch (MPC8xx);
1863 define relocation offset in DPRAM [SCC4]
1866 Use OSCM clock mode on MBX8xx board. Be careful,
1867 wrong setting might damage your board. Read
1868 doc/README.MBX before setting this variable!
1870 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1871 Offset of the bootmode word in DPRAM used by post
1872 (Power On Self Tests). This definition overrides
1873 #define'd default value in commproc.h resp.
1876 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1877 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1878 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1879 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1880 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1881 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1882 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1883 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1884 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1886 Building the Software:
1887 ======================
1889 Building U-Boot has been tested in native PPC environments (on a
1890 PowerBook G3 running LinuxPPC 2000) and in cross environments
1891 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1894 If you are not using a native PPC environment, it is assumed that you
1895 have the GNU cross compiling tools available in your path and named
1896 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1897 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1898 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1901 CROSS_COMPILE = ppc_4xx-
1904 U-Boot is intended to be simple to build. After installing the
1905 sources you must configure U-Boot for one specific board type. This
1910 where "NAME_config" is the name of one of the existing
1911 configurations; the following names are supported:
1913 ADCIOP_config GTH_config TQM850L_config
1914 ADS860_config IP860_config TQM855L_config
1915 AR405_config IVML24_config TQM860L_config
1916 CANBT_config IVMS8_config WALNUT405_config
1917 CPCI405_config LANTEC_config cogent_common_config
1918 CPCIISER4_config MBX_config cogent_mpc8260_config
1919 CU824_config MBX860T_config cogent_mpc8xx_config
1920 ESTEEM192E_config RPXlite_config hermes_config
1921 ETX094_config RPXsuper_config hymod_config
1922 FADS823_config SM850_config lwmon_config
1923 FADS850SAR_config SPD823TS_config pcu_e_config
1924 FADS860T_config SXNI855T_config rsdproto_config
1925 FPS850L_config Sandpoint8240_config sbc8260_config
1926 GENIETV_config TQM823L_config PIP405_config
1927 GEN860T_config EBONY_config FPS860L_config
1928 ELPT860_config cmi_mpc5xx_config NETVIA_config
1929 at91rm9200dk_config omap1510inn_config MPC8260ADS_config
1930 omap1610inn_config ZPC1900_config MPC8540ADS_config
1931 MPC8560ADS_config QS850_config QS823_config
1932 QS860T_config DUET_ADS_config omap1610h2_config
1934 Note: for some board special configuration names may exist; check if
1935 additional information is available from the board vendor; for
1936 instance, the TQM8xxL systems run normally at 50 MHz and use a
1937 SCC for 10baseT ethernet; there are also systems with 80 MHz
1938 CPU clock, and an optional Fast Ethernet module is available
1939 for CPU's with FEC. You can select such additional "features"
1940 when chosing the configuration, i. e.
1943 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1945 make TQM860L_FEC_config
1946 - will configure for a TQM860L at 50MHz with FEC for ethernet
1948 make TQM860L_80MHz_config
1949 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1952 make TQM860L_FEC_80MHz_config
1953 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1955 make TQM823L_LCD_config
1956 - will configure for a TQM823L with U-Boot console on LCD
1958 make TQM823L_LCD_80MHz_config
1959 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1964 Finally, type "make all", and you should get some working U-Boot
1965 images ready for download to / installation on your system:
1967 - "u-boot.bin" is a raw binary image
1968 - "u-boot" is an image in ELF binary format
1969 - "u-boot.srec" is in Motorola S-Record format
1972 Please be aware that the Makefiles assume you are using GNU make, so
1973 for instance on NetBSD you might need to use "gmake" instead of
1977 If the system board that you have is not listed, then you will need
1978 to port U-Boot to your hardware platform. To do this, follow these
1981 1. Add a new configuration option for your board to the toplevel
1982 "Makefile" and to the "MAKEALL" script, using the existing
1983 entries as examples. Note that here and at many other places
1984 boards and other names are listed in alphabetical sort order. Please
1986 2. Create a new directory to hold your board specific code. Add any
1987 files you need. In your board directory, you will need at least
1988 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1989 3. Create a new configuration file "include/configs/<board>.h" for
1991 3. If you're porting U-Boot to a new CPU, then also create a new
1992 directory to hold your CPU specific code. Add any files you need.
1993 4. Run "make <board>_config" with your new name.
1994 5. Type "make", and you should get a working "u-boot.srec" file
1995 to be installed on your target system.
1996 6. Debug and solve any problems that might arise.
1997 [Of course, this last step is much harder than it sounds.]
2000 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2001 ==============================================================
2003 If you have modified U-Boot sources (for instance added a new board
2004 or support for new devices, a new CPU, etc.) you are expected to
2005 provide feedback to the other developers. The feedback normally takes
2006 the form of a "patch", i. e. a context diff against a certain (latest
2007 official or latest in CVS) version of U-Boot sources.
2009 But before you submit such a patch, please verify that your modifi-
2010 cation did not break existing code. At least make sure that *ALL* of
2011 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2012 just run the "MAKEALL" script, which will configure and build U-Boot
2013 for ALL supported system. Be warned, this will take a while. You can
2014 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2015 environment variable to the script, i. e. to use the cross tools from
2016 MontaVista's Hard Hat Linux you can type
2018 CROSS_COMPILE=ppc_8xx- MAKEALL
2020 or to build on a native PowerPC system you can type
2022 CROSS_COMPILE=' ' MAKEALL
2024 See also "U-Boot Porting Guide" below.
2027 Monitor Commands - Overview:
2028 ============================
2030 go - start application at address 'addr'
2031 run - run commands in an environment variable
2032 bootm - boot application image from memory
2033 bootp - boot image via network using BootP/TFTP protocol
2034 tftpboot- boot image via network using TFTP protocol
2035 and env variables "ipaddr" and "serverip"
2036 (and eventually "gatewayip")
2037 rarpboot- boot image via network using RARP/TFTP protocol
2038 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2039 loads - load S-Record file over serial line
2040 loadb - load binary file over serial line (kermit mode)
2042 mm - memory modify (auto-incrementing)
2043 nm - memory modify (constant address)
2044 mw - memory write (fill)
2046 cmp - memory compare
2047 crc32 - checksum calculation
2048 imd - i2c memory display
2049 imm - i2c memory modify (auto-incrementing)
2050 inm - i2c memory modify (constant address)
2051 imw - i2c memory write (fill)
2052 icrc32 - i2c checksum calculation
2053 iprobe - probe to discover valid I2C chip addresses
2054 iloop - infinite loop on address range
2055 isdram - print SDRAM configuration information
2056 sspi - SPI utility commands
2057 base - print or set address offset
2058 printenv- print environment variables
2059 setenv - set environment variables
2060 saveenv - save environment variables to persistent storage
2061 protect - enable or disable FLASH write protection
2062 erase - erase FLASH memory
2063 flinfo - print FLASH memory information
2064 bdinfo - print Board Info structure
2065 iminfo - print header information for application image
2066 coninfo - print console devices and informations
2067 ide - IDE sub-system
2068 loop - infinite loop on address range
2069 mtest - simple RAM test
2070 icache - enable or disable instruction cache
2071 dcache - enable or disable data cache
2072 reset - Perform RESET of the CPU
2073 echo - echo args to console
2074 version - print monitor version
2075 help - print online help
2076 ? - alias for 'help'
2079 Monitor Commands - Detailed Description:
2080 ========================================
2084 For now: just type "help <command>".
2087 Environment Variables:
2088 ======================
2090 U-Boot supports user configuration using Environment Variables which
2091 can be made persistent by saving to Flash memory.
2093 Environment Variables are set using "setenv", printed using
2094 "printenv", and saved to Flash using "saveenv". Using "setenv"
2095 without a value can be used to delete a variable from the
2096 environment. As long as you don't save the environment you are
2097 working with an in-memory copy. In case the Flash area containing the
2098 environment is erased by accident, a default environment is provided.
2100 Some configuration options can be set using Environment Variables:
2102 baudrate - see CONFIG_BAUDRATE
2104 bootdelay - see CONFIG_BOOTDELAY
2106 bootcmd - see CONFIG_BOOTCOMMAND
2108 bootargs - Boot arguments when booting an RTOS image
2110 bootfile - Name of the image to load with TFTP
2112 autoload - if set to "no" (any string beginning with 'n'),
2113 "bootp" will just load perform a lookup of the
2114 configuration from the BOOTP server, but not try to
2115 load any image using TFTP
2117 autostart - if set to "yes", an image loaded using the "bootp",
2118 "rarpboot", "tftpboot" or "diskboot" commands will
2119 be automatically started (by internally calling
2122 If set to "no", a standalone image passed to the
2123 "bootm" command will be copied to the load address
2124 (and eventually uncompressed), but NOT be started.
2125 This can be used to load and uncompress arbitrary
2128 initrd_high - restrict positioning of initrd images:
2129 If this variable is not set, initrd images will be
2130 copied to the highest possible address in RAM; this
2131 is usually what you want since it allows for
2132 maximum initrd size. If for some reason you want to
2133 make sure that the initrd image is loaded below the
2134 CFG_BOOTMAPSZ limit, you can set this environment
2135 variable to a value of "no" or "off" or "0".
2136 Alternatively, you can set it to a maximum upper
2137 address to use (U-Boot will still check that it
2138 does not overwrite the U-Boot stack and data).
2140 For instance, when you have a system with 16 MB
2141 RAM, and want to reserve 4 MB from use by Linux,
2142 you can do this by adding "mem=12M" to the value of
2143 the "bootargs" variable. However, now you must make
2144 sure that the initrd image is placed in the first
2145 12 MB as well - this can be done with
2147 setenv initrd_high 00c00000
2149 If you set initrd_high to 0xFFFFFFFF, this is an
2150 indication to U-Boot that all addresses are legal
2151 for the Linux kernel, including addresses in flash
2152 memory. In this case U-Boot will NOT COPY the
2153 ramdisk at all. This may be useful to reduce the
2154 boot time on your system, but requires that this
2155 feature is supported by your Linux kernel.
2157 ipaddr - IP address; needed for tftpboot command
2159 loadaddr - Default load address for commands like "bootp",
2160 "rarpboot", "tftpboot", "loadb" or "diskboot"
2162 loads_echo - see CONFIG_LOADS_ECHO
2164 serverip - TFTP server IP address; needed for tftpboot command
2166 bootretry - see CONFIG_BOOT_RETRY_TIME
2168 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2170 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2173 The following environment variables may be used and automatically
2174 updated by the network boot commands ("bootp" and "rarpboot"),
2175 depending the information provided by your boot server:
2177 bootfile - see above
2178 dnsip - IP address of your Domain Name Server
2179 dnsip2 - IP address of your secondary Domain Name Server
2180 gatewayip - IP address of the Gateway (Router) to use
2181 hostname - Target hostname
2183 netmask - Subnet Mask
2184 rootpath - Pathname of the root filesystem on the NFS server
2185 serverip - see above
2188 There are two special Environment Variables:
2190 serial# - contains hardware identification information such
2191 as type string and/or serial number
2192 ethaddr - Ethernet address
2194 These variables can be set only once (usually during manufacturing of
2195 the board). U-Boot refuses to delete or overwrite these variables
2196 once they have been set once.
2199 Further special Environment Variables:
2201 ver - Contains the U-Boot version string as printed
2202 with the "version" command. This variable is
2203 readonly (see CONFIG_VERSION_VARIABLE).
2206 Please note that changes to some configuration parameters may take
2207 only effect after the next boot (yes, that's just like Windoze :-).
2210 Command Line Parsing:
2211 =====================
2213 There are two different command line parsers available with U-Boot:
2214 the old "simple" one, and the much more powerful "hush" shell:
2216 Old, simple command line parser:
2217 --------------------------------
2219 - supports environment variables (through setenv / saveenv commands)
2220 - several commands on one line, separated by ';'
2221 - variable substitution using "... $(name) ..." syntax
2222 - special characters ('$', ';') can be escaped by prefixing with '\',
2224 setenv bootcmd bootm \$(address)
2225 - You can also escape text by enclosing in single apostrophes, for example:
2226 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2231 - similar to Bourne shell, with control structures like
2232 if...then...else...fi, for...do...done; while...do...done,
2233 until...do...done, ...
2234 - supports environment ("global") variables (through setenv / saveenv
2235 commands) and local shell variables (through standard shell syntax
2236 "name=value"); only environment variables can be used with "run"
2242 (1) If a command line (or an environment variable executed by a "run"
2243 command) contains several commands separated by semicolon, and
2244 one of these commands fails, then the remaining commands will be
2247 (2) If you execute several variables with one call to run (i. e.
2248 calling run with a list af variables as arguments), any failing
2249 command will cause "run" to terminate, i. e. the remaining
2250 variables are not executed.
2252 Note for Redundant Ethernet Interfaces:
2253 =======================================
2255 Some boards come with redundant ethernet interfaces; U-Boot supports
2256 such configurations and is capable of automatic selection of a
2257 "working" interface when needed. MAC assignment works as follows:
2259 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2260 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2261 "eth1addr" (=>eth1), "eth2addr", ...
2263 If the network interface stores some valid MAC address (for instance
2264 in SROM), this is used as default address if there is NO correspon-
2265 ding setting in the environment; if the corresponding environment
2266 variable is set, this overrides the settings in the card; that means:
2268 o If the SROM has a valid MAC address, and there is no address in the
2269 environment, the SROM's address is used.
2271 o If there is no valid address in the SROM, and a definition in the
2272 environment exists, then the value from the environment variable is
2275 o If both the SROM and the environment contain a MAC address, and
2276 both addresses are the same, this MAC address is used.
2278 o If both the SROM and the environment contain a MAC address, and the
2279 addresses differ, the value from the environment is used and a
2282 o If neither SROM nor the environment contain a MAC address, an error
2289 The "boot" commands of this monitor operate on "image" files which
2290 can be basicly anything, preceeded by a special header; see the
2291 definitions in include/image.h for details; basicly, the header
2292 defines the following image properties:
2294 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2295 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2296 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2297 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2298 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2299 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2300 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC).
2301 * Compression Type (uncompressed, gzip, bzip2)
2307 The header is marked by a special Magic Number, and both the header
2308 and the data portions of the image are secured against corruption by
2315 Although U-Boot should support any OS or standalone application
2316 easily, the main focus has always been on Linux during the design of
2319 U-Boot includes many features that so far have been part of some
2320 special "boot loader" code within the Linux kernel. Also, any
2321 "initrd" images to be used are no longer part of one big Linux image;
2322 instead, kernel and "initrd" are separate images. This implementation
2323 serves several purposes:
2325 - the same features can be used for other OS or standalone
2326 applications (for instance: using compressed images to reduce the
2327 Flash memory footprint)
2329 - it becomes much easier to port new Linux kernel versions because
2330 lots of low-level, hardware dependent stuff are done by U-Boot
2332 - the same Linux kernel image can now be used with different "initrd"
2333 images; of course this also means that different kernel images can
2334 be run with the same "initrd". This makes testing easier (you don't
2335 have to build a new "zImage.initrd" Linux image when you just
2336 change a file in your "initrd"). Also, a field-upgrade of the
2337 software is easier now.
2343 Porting Linux to U-Boot based systems:
2344 ---------------------------------------
2346 U-Boot cannot save you from doing all the necessary modifications to
2347 configure the Linux device drivers for use with your target hardware
2348 (no, we don't intend to provide a full virtual machine interface to
2351 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2353 Just make sure your machine specific header file (for instance
2354 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2355 Information structure as we define in include/u-boot.h, and make
2356 sure that your definition of IMAP_ADDR uses the same value as your
2357 U-Boot configuration in CFG_IMMR.
2360 Configuring the Linux kernel:
2361 -----------------------------
2363 No specific requirements for U-Boot. Make sure you have some root
2364 device (initial ramdisk, NFS) for your target system.
2367 Building a Linux Image:
2368 -----------------------
2370 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2371 not used. If you use recent kernel source, a new build target
2372 "uImage" will exist which automatically builds an image usable by
2373 U-Boot. Most older kernels also have support for a "pImage" target,
2374 which was introduced for our predecessor project PPCBoot and uses a
2375 100% compatible format.
2384 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2385 encapsulate a compressed Linux kernel image with header information,
2386 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2388 * build a standard "vmlinux" kernel image (in ELF binary format):
2390 * convert the kernel into a raw binary image:
2392 ${CROSS_COMPILE}-objcopy -O binary \
2393 -R .note -R .comment \
2394 -S vmlinux linux.bin
2396 * compress the binary image:
2400 * package compressed binary image for U-Boot:
2402 mkimage -A ppc -O linux -T kernel -C gzip \
2403 -a 0 -e 0 -n "Linux Kernel Image" \
2404 -d linux.bin.gz uImage
2407 The "mkimage" tool can also be used to create ramdisk images for use
2408 with U-Boot, either separated from the Linux kernel image, or
2409 combined into one file. "mkimage" encapsulates the images with a 64
2410 byte header containing information about target architecture,
2411 operating system, image type, compression method, entry points, time
2412 stamp, CRC32 checksums, etc.
2414 "mkimage" can be called in two ways: to verify existing images and
2415 print the header information, or to build new images.
2417 In the first form (with "-l" option) mkimage lists the information
2418 contained in the header of an existing U-Boot image; this includes
2419 checksum verification:
2421 tools/mkimage -l image
2422 -l ==> list image header information
2424 The second form (with "-d" option) is used to build a U-Boot image
2425 from a "data file" which is used as image payload:
2427 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2428 -n name -d data_file image
2429 -A ==> set architecture to 'arch'
2430 -O ==> set operating system to 'os'
2431 -T ==> set image type to 'type'
2432 -C ==> set compression type 'comp'
2433 -a ==> set load address to 'addr' (hex)
2434 -e ==> set entry point to 'ep' (hex)
2435 -n ==> set image name to 'name'
2436 -d ==> use image data from 'datafile'
2438 Right now, all Linux kernels use the same load address (0x00000000),
2439 but the entry point address depends on the kernel version:
2441 - 2.2.x kernels have the entry point at 0x0000000C,
2442 - 2.3.x and later kernels have the entry point at 0x00000000.
2444 So a typical call to build a U-Boot image would read:
2446 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2447 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2448 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2449 > examples/uImage.TQM850L
2450 Image Name: 2.4.4 kernel for TQM850L
2451 Created: Wed Jul 19 02:34:59 2000
2452 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2453 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2454 Load Address: 0x00000000
2455 Entry Point: 0x00000000
2457 To verify the contents of the image (or check for corruption):
2459 -> tools/mkimage -l examples/uImage.TQM850L
2460 Image Name: 2.4.4 kernel for TQM850L
2461 Created: Wed Jul 19 02:34:59 2000
2462 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2463 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2464 Load Address: 0x00000000
2465 Entry Point: 0x00000000
2467 NOTE: for embedded systems where boot time is critical you can trade
2468 speed for memory and install an UNCOMPRESSED image instead: this
2469 needs more space in Flash, but boots much faster since it does not
2470 need to be uncompressed:
2472 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2473 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2474 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2475 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2476 > examples/uImage.TQM850L-uncompressed
2477 Image Name: 2.4.4 kernel for TQM850L
2478 Created: Wed Jul 19 02:34:59 2000
2479 Image Type: PowerPC Linux Kernel Image (uncompressed)
2480 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2481 Load Address: 0x00000000
2482 Entry Point: 0x00000000
2485 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2486 when your kernel is intended to use an initial ramdisk:
2488 -> tools/mkimage -n 'Simple Ramdisk Image' \
2489 > -A ppc -O linux -T ramdisk -C gzip \
2490 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2491 Image Name: Simple Ramdisk Image
2492 Created: Wed Jan 12 14:01:50 2000
2493 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2494 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2495 Load Address: 0x00000000
2496 Entry Point: 0x00000000
2499 Installing a Linux Image:
2500 -------------------------
2502 To downloading a U-Boot image over the serial (console) interface,
2503 you must convert the image to S-Record format:
2505 objcopy -I binary -O srec examples/image examples/image.srec
2507 The 'objcopy' does not understand the information in the U-Boot
2508 image header, so the resulting S-Record file will be relative to
2509 address 0x00000000. To load it to a given address, you need to
2510 specify the target address as 'offset' parameter with the 'loads'
2513 Example: install the image to address 0x40100000 (which on the
2514 TQM8xxL is in the first Flash bank):
2516 => erase 40100000 401FFFFF
2522 ## Ready for S-Record download ...
2523 ~>examples/image.srec
2524 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2526 15989 15990 15991 15992
2527 [file transfer complete]
2529 ## Start Addr = 0x00000000
2532 You can check the success of the download using the 'iminfo' command;
2533 this includes a checksum verification so you can be sure no data
2534 corruption happened:
2538 ## Checking Image at 40100000 ...
2539 Image Name: 2.2.13 for initrd on TQM850L
2540 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2541 Data Size: 335725 Bytes = 327 kB = 0 MB
2542 Load Address: 00000000
2543 Entry Point: 0000000c
2544 Verifying Checksum ... OK
2550 The "bootm" command is used to boot an application that is stored in
2551 memory (RAM or Flash). In case of a Linux kernel image, the contents
2552 of the "bootargs" environment variable is passed to the kernel as
2553 parameters. You can check and modify this variable using the
2554 "printenv" and "setenv" commands:
2557 => printenv bootargs
2558 bootargs=root=/dev/ram
2560 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2562 => printenv bootargs
2563 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2566 ## Booting Linux kernel at 40020000 ...
2567 Image Name: 2.2.13 for NFS on TQM850L
2568 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2569 Data Size: 381681 Bytes = 372 kB = 0 MB
2570 Load Address: 00000000
2571 Entry Point: 0000000c
2572 Verifying Checksum ... OK
2573 Uncompressing Kernel Image ... OK
2574 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
2575 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2576 time_init: decrementer frequency = 187500000/60
2577 Calibrating delay loop... 49.77 BogoMIPS
2578 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2581 If you want to boot a Linux kernel with initial ram disk, you pass
2582 the memory addresses of both the kernel and the initrd image (PPBCOOT
2583 format!) to the "bootm" command:
2585 => imi 40100000 40200000
2587 ## Checking Image at 40100000 ...
2588 Image Name: 2.2.13 for initrd on TQM850L
2589 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2590 Data Size: 335725 Bytes = 327 kB = 0 MB
2591 Load Address: 00000000
2592 Entry Point: 0000000c
2593 Verifying Checksum ... OK
2595 ## Checking Image at 40200000 ...
2596 Image Name: Simple Ramdisk Image
2597 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2598 Data Size: 566530 Bytes = 553 kB = 0 MB
2599 Load Address: 00000000
2600 Entry Point: 00000000
2601 Verifying Checksum ... OK
2603 => bootm 40100000 40200000
2604 ## Booting Linux kernel at 40100000 ...
2605 Image Name: 2.2.13 for initrd on TQM850L
2606 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2607 Data Size: 335725 Bytes = 327 kB = 0 MB
2608 Load Address: 00000000
2609 Entry Point: 0000000c
2610 Verifying Checksum ... OK
2611 Uncompressing Kernel Image ... OK
2612 ## Loading RAMDisk Image at 40200000 ...
2613 Image Name: Simple Ramdisk Image
2614 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2615 Data Size: 566530 Bytes = 553 kB = 0 MB
2616 Load Address: 00000000
2617 Entry Point: 00000000
2618 Verifying Checksum ... OK
2619 Loading Ramdisk ... OK
2620 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
2621 Boot arguments: root=/dev/ram
2622 time_init: decrementer frequency = 187500000/60
2623 Calibrating delay loop... 49.77 BogoMIPS
2625 RAMDISK: Compressed image found at block 0
2626 VFS: Mounted root (ext2 filesystem).
2630 More About U-Boot Image Types:
2631 ------------------------------
2633 U-Boot supports the following image types:
2635 "Standalone Programs" are directly runnable in the environment
2636 provided by U-Boot; it is expected that (if they behave
2637 well) you can continue to work in U-Boot after return from
2638 the Standalone Program.
2639 "OS Kernel Images" are usually images of some Embedded OS which
2640 will take over control completely. Usually these programs
2641 will install their own set of exception handlers, device
2642 drivers, set up the MMU, etc. - this means, that you cannot
2643 expect to re-enter U-Boot except by resetting the CPU.
2644 "RAMDisk Images" are more or less just data blocks, and their
2645 parameters (address, size) are passed to an OS kernel that is
2647 "Multi-File Images" contain several images, typically an OS
2648 (Linux) kernel image and one or more data images like
2649 RAMDisks. This construct is useful for instance when you want
2650 to boot over the network using BOOTP etc., where the boot
2651 server provides just a single image file, but you want to get
2652 for instance an OS kernel and a RAMDisk image.
2654 "Multi-File Images" start with a list of image sizes, each
2655 image size (in bytes) specified by an "uint32_t" in network
2656 byte order. This list is terminated by an "(uint32_t)0".
2657 Immediately after the terminating 0 follow the images, one by
2658 one, all aligned on "uint32_t" boundaries (size rounded up to
2659 a multiple of 4 bytes).
2661 "Firmware Images" are binary images containing firmware (like
2662 U-Boot or FPGA images) which usually will be programmed to
2665 "Script files" are command sequences that will be executed by
2666 U-Boot's command interpreter; this feature is especially
2667 useful when you configure U-Boot to use a real shell (hush)
2668 as command interpreter.
2674 One of the features of U-Boot is that you can dynamically load and
2675 run "standalone" applications, which can use some resources of
2676 U-Boot like console I/O functions or interrupt services.
2678 Two simple examples are included with the sources:
2683 'examples/hello_world.c' contains a small "Hello World" Demo
2684 application; it is automatically compiled when you build U-Boot.
2685 It's configured to run at address 0x00040004, so you can play with it
2689 ## Ready for S-Record download ...
2690 ~>examples/hello_world.srec
2691 1 2 3 4 5 6 7 8 9 10 11 ...
2692 [file transfer complete]
2694 ## Start Addr = 0x00040004
2696 => go 40004 Hello World! This is a test.
2697 ## Starting application at 0x00040004 ...
2708 Hit any key to exit ...
2710 ## Application terminated, rc = 0x0
2712 Another example, which demonstrates how to register a CPM interrupt
2713 handler with the U-Boot code, can be found in 'examples/timer.c'.
2714 Here, a CPM timer is set up to generate an interrupt every second.
2715 The interrupt service routine is trivial, just printing a '.'
2716 character, but this is just a demo program. The application can be
2717 controlled by the following keys:
2719 ? - print current values og the CPM Timer registers
2720 b - enable interrupts and start timer
2721 e - stop timer and disable interrupts
2722 q - quit application
2725 ## Ready for S-Record download ...
2726 ~>examples/timer.srec
2727 1 2 3 4 5 6 7 8 9 10 11 ...
2728 [file transfer complete]
2730 ## Start Addr = 0x00040004
2733 ## Starting application at 0x00040004 ...
2736 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2739 [q, b, e, ?] Set interval 1000000 us
2742 [q, b, e, ?] ........
2743 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2746 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2749 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2752 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2754 [q, b, e, ?] ...Stopping timer
2756 [q, b, e, ?] ## Application terminated, rc = 0x0
2762 Over time, many people have reported problems when trying to use the
2763 "minicom" terminal emulation program for serial download. I (wd)
2764 consider minicom to be broken, and recommend not to use it. Under
2765 Unix, I recommend to use C-Kermit for general purpose use (and
2766 especially for kermit binary protocol download ("loadb" command), and
2767 use "cu" for S-Record download ("loads" command).
2769 Nevertheless, if you absolutely want to use it try adding this
2770 configuration to your "File transfer protocols" section:
2772 Name Program Name U/D FullScr IO-Red. Multi
2773 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2774 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2780 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2781 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2783 Building requires a cross environment; it is known to work on
2784 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2785 need gmake since the Makefiles are not compatible with BSD make).
2786 Note that the cross-powerpc package does not install include files;
2787 attempting to build U-Boot will fail because <machine/ansi.h> is
2788 missing. This file has to be installed and patched manually:
2790 # cd /usr/pkg/cross/powerpc-netbsd/include
2792 # ln -s powerpc machine
2793 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2794 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2796 Native builds *don't* work due to incompatibilities between native
2797 and U-Boot include files.
2799 Booting assumes that (the first part of) the image booted is a
2800 stage-2 loader which in turn loads and then invokes the kernel
2801 proper. Loader sources will eventually appear in the NetBSD source
2802 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2803 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2807 Implementation Internals:
2808 =========================
2810 The following is not intended to be a complete description of every
2811 implementation detail. However, it should help to understand the
2812 inner workings of U-Boot and make it easier to port it to custom
2816 Initial Stack, Global Data:
2817 ---------------------------
2819 The implementation of U-Boot is complicated by the fact that U-Boot
2820 starts running out of ROM (flash memory), usually without access to
2821 system RAM (because the memory controller is not initialized yet).
2822 This means that we don't have writable Data or BSS segments, and BSS
2823 is not initialized as zero. To be able to get a C environment working
2824 at all, we have to allocate at least a minimal stack. Implementation
2825 options for this are defined and restricted by the CPU used: Some CPU
2826 models provide on-chip memory (like the IMMR area on MPC8xx and
2827 MPC826x processors), on others (parts of) the data cache can be
2828 locked as (mis-) used as memory, etc.
2830 Chris Hallinan posted a good summary of these issues to the
2831 u-boot-users mailing list:
2833 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2834 From: "Chris Hallinan" <clh@net1plus.com>
2835 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2838 Correct me if I'm wrong, folks, but the way I understand it
2839 is this: Using DCACHE as initial RAM for Stack, etc, does not
2840 require any physical RAM backing up the cache. The cleverness
2841 is that the cache is being used as a temporary supply of
2842 necessary storage before the SDRAM controller is setup. It's
2843 beyond the scope of this list to expain the details, but you
2844 can see how this works by studying the cache architecture and
2845 operation in the architecture and processor-specific manuals.
2847 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2848 is another option for the system designer to use as an
2849 initial stack/ram area prior to SDRAM being available. Either
2850 option should work for you. Using CS 4 should be fine if your
2851 board designers haven't used it for something that would
2852 cause you grief during the initial boot! It is frequently not
2855 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2856 with your processor/board/system design. The default value
2857 you will find in any recent u-boot distribution in
2858 Walnut405.h should work for you. I'd set it to a value larger
2859 than your SDRAM module. If you have a 64MB SDRAM module, set
2860 it above 400_0000. Just make sure your board has no resources
2861 that are supposed to respond to that address! That code in
2862 start.S has been around a while and should work as is when
2863 you get the config right.
2868 It is essential to remember this, since it has some impact on the C
2869 code for the initialization procedures:
2871 * Initialized global data (data segment) is read-only. Do not attempt
2874 * Do not use any unitialized global data (or implicitely initialized
2875 as zero data - BSS segment) at all - this is undefined, initiali-
2876 zation is performed later (when relocating to RAM).
2878 * Stack space is very limited. Avoid big data buffers or things like
2881 Having only the stack as writable memory limits means we cannot use
2882 normal global data to share information beween the code. But it
2883 turned out that the implementation of U-Boot can be greatly
2884 simplified by making a global data structure (gd_t) available to all
2885 functions. We could pass a pointer to this data as argument to _all_
2886 functions, but this would bloat the code. Instead we use a feature of
2887 the GCC compiler (Global Register Variables) to share the data: we
2888 place a pointer (gd) to the global data into a register which we
2889 reserve for this purpose.
2891 When choosing a register for such a purpose we are restricted by the
2892 relevant (E)ABI specifications for the current architecture, and by
2893 GCC's implementation.
2895 For PowerPC, the following registers have specific use:
2898 R3-R4: parameter passing and return values
2899 R5-R10: parameter passing
2900 R13: small data area pointer
2904 (U-Boot also uses R14 as internal GOT pointer.)
2906 ==> U-Boot will use R29 to hold a pointer to the global data
2908 Note: on PPC, we could use a static initializer (since the
2909 address of the global data structure is known at compile time),
2910 but it turned out that reserving a register results in somewhat
2911 smaller code - although the code savings are not that big (on
2912 average for all boards 752 bytes for the whole U-Boot image,
2913 624 text + 127 data).
2915 On ARM, the following registers are used:
2917 R0: function argument word/integer result
2918 R1-R3: function argument word
2920 R10: stack limit (used only if stack checking if enabled)
2921 R11: argument (frame) pointer
2922 R12: temporary workspace
2925 R15: program counter
2927 ==> U-Boot will use R8 to hold a pointer to the global data
2933 U-Boot runs in system state and uses physical addresses, i.e. the
2934 MMU is not used either for address mapping nor for memory protection.
2936 The available memory is mapped to fixed addresses using the memory
2937 controller. In this process, a contiguous block is formed for each
2938 memory type (Flash, SDRAM, SRAM), even when it consists of several
2939 physical memory banks.
2941 U-Boot is installed in the first 128 kB of the first Flash bank (on
2942 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2943 booting and sizing and initializing DRAM, the code relocates itself
2944 to the upper end of DRAM. Immediately below the U-Boot code some
2945 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2946 configuration setting]. Below that, a structure with global Board
2947 Info data is placed, followed by the stack (growing downward).
2949 Additionally, some exception handler code is copied to the low 8 kB
2950 of DRAM (0x00000000 ... 0x00001FFF).
2952 So a typical memory configuration with 16 MB of DRAM could look like
2955 0x0000 0000 Exception Vector code
2958 0x0000 2000 Free for Application Use
2964 0x00FB FF20 Monitor Stack (Growing downward)
2965 0x00FB FFAC Board Info Data and permanent copy of global data
2966 0x00FC 0000 Malloc Arena
2969 0x00FE 0000 RAM Copy of Monitor Code
2970 ... eventually: LCD or video framebuffer
2971 ... eventually: pRAM (Protected RAM - unchanged by reset)
2972 0x00FF FFFF [End of RAM]
2975 System Initialization:
2976 ----------------------
2978 In the reset configuration, U-Boot starts at the reset entry point
2979 (on most PowerPC systens at address 0x00000100). Because of the reset
2980 configuration for CS0# this is a mirror of the onboard Flash memory.
2981 To be able to re-map memory U-Boot then jumps to its link address.
2982 To be able to implement the initialization code in C, a (small!)
2983 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2984 which provide such a feature like MPC8xx or MPC8260), or in a locked
2985 part of the data cache. After that, U-Boot initializes the CPU core,
2986 the caches and the SIU.
2988 Next, all (potentially) available memory banks are mapped using a
2989 preliminary mapping. For example, we put them on 512 MB boundaries
2990 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2991 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2992 programmed for SDRAM access. Using the temporary configuration, a
2993 simple memory test is run that determines the size of the SDRAM
2996 When there is more than one SDRAM bank, and the banks are of
2997 different size, the largest is mapped first. For equal size, the first
2998 bank (CS2#) is mapped first. The first mapping is always for address
2999 0x00000000, with any additional banks following immediately to create
3000 contiguous memory starting from 0.
3002 Then, the monitor installs itself at the upper end of the SDRAM area
3003 and allocates memory for use by malloc() and for the global Board
3004 Info data; also, the exception vector code is copied to the low RAM
3005 pages, and the final stack is set up.
3007 Only after this relocation will you have a "normal" C environment;
3008 until that you are restricted in several ways, mostly because you are
3009 running from ROM, and because the code will have to be relocated to a
3013 U-Boot Porting Guide:
3014 ----------------------
3016 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3020 int main (int argc, char *argv[])
3022 sighandler_t no_more_time;
3024 signal (SIGALRM, no_more_time);
3025 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3027 if (available_money > available_manpower) {
3028 pay consultant to port U-Boot;
3032 Download latest U-Boot source;
3034 Subscribe to u-boot-users mailing list;
3037 email ("Hi, I am new to U-Boot, how do I get started?");
3041 Read the README file in the top level directory;
3042 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3043 Read the source, Luke;
3046 if (available_money > toLocalCurrency ($2500)) {
3049 Add a lot of aggravation and time;
3052 Create your own board support subdirectory;
3054 Create your own board config file;
3058 Add / modify source code;
3062 email ("Hi, I am having problems...");
3064 Send patch file to Wolfgang;
3069 void no_more_time (int sig)
3078 All contributions to U-Boot should conform to the Linux kernel
3079 coding style; see the file "Documentation/CodingStyle" in your Linux
3080 kernel source directory.
3082 Please note that U-Boot is implemented in C (and to some small parts
3083 in Assembler); no C++ is used, so please do not use C++ style
3084 comments (//) in your code.
3086 Please also stick to the following formatting rules:
3087 - remove any trailing white space
3088 - use TAB characters for indentation, not spaces
3089 - make sure NOT to use DOS '\r\n' line feeds
3090 - do not add more than 2 empty lines to source files
3091 - do not add trailing empty lines to source files
3093 Submissions which do not conform to the standards may be returned
3094 with a request to reformat the changes.
3100 Since the number of patches for U-Boot is growing, we need to
3101 establish some rules. Submissions which do not conform to these rules
3102 may be rejected, even when they contain important and valuable stuff.
3105 When you send a patch, please include the following information with
3108 * For bug fixes: a description of the bug and how your patch fixes
3109 this bug. Please try to include a way of demonstrating that the
3110 patch actually fixes something.
3112 * For new features: a description of the feature and your
3115 * A CHANGELOG entry as plaintext (separate from the patch)
3117 * For major contributions, your entry to the CREDITS file
3119 * When you add support for a new board, don't forget to add this
3120 board to the MAKEALL script, too.
3122 * If your patch adds new configuration options, don't forget to
3123 document these in the README file.
3125 * The patch itself. If you are accessing the CVS repository use "cvs
3126 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3127 version of diff does not support these options, then get the latest
3128 version of GNU diff.
3130 The current directory when running this command shall be the top
3131 level directory of the U-Boot source tree, or it's parent directory
3132 (i. e. please make sure that your patch includes sufficient
3133 directory information for the affected files).
3135 We accept patches as plain text, MIME attachments or as uuencoded
3138 * If one logical set of modifications affects or creates several
3139 files, all these changes shall be submitted in a SINGLE patch file.
3141 * Changesets that contain different, unrelated modifications shall be
3142 submitted as SEPARATE patches, one patch per changeset.
3147 * Before sending the patch, run the MAKEALL script on your patched
3148 source tree and make sure that no errors or warnings are reported
3149 for any of the boards.
3151 * Keep your modifications to the necessary minimum: A patch
3152 containing several unrelated changes or arbitrary reformats will be
3153 returned with a request to re-formatting / split it.
3155 * If you modify existing code, make sure that your new code does not
3156 add to the memory footprint of the code ;-) Small is beautiful!
3157 When adding new features, these should compile conditionally only
3158 (using #ifdef), and the resulting code with the new feature
3159 disabled must not need more memory than the old code without your
projects / karo-tx-uboot.git / blob