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
665 Set this to define that instead of a reset Pin, the
666 routine ide_set_reset(int idereset) will be used.
671 Set this to enable ATAPI support.
676 Set this to enable support for disks larger than 137GB
677 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
678 Whithout these , LBA48 support uses 32bit variables and will 'only'
679 support disks up to 2.1TB.
682 When enabled, makes the IDE subsystem use 64bit sector addresses.
686 At the moment only there is only support for the
687 SYM53C8XX SCSI controller; define
688 CONFIG_SCSI_SYM53C8XX to enable it.
690 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
691 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
692 CFG_SCSI_MAX_LUN] can be adjusted to define the
693 maximum numbers of LUNs, SCSI ID's and target
695 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
697 - NETWORK Support (PCI):
699 Support for Intel 8254x gigabit chips.
702 Support for Intel 82557/82559/82559ER chips.
703 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
704 write routine for first time initialisation.
707 Support for Digital 2114x chips.
708 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
709 modem chip initialisation (KS8761/QS6611).
712 Support for National dp83815 chips.
715 Support for National dp8382[01] gigabit chips.
717 - NETWORK Support (other):
719 CONFIG_DRIVER_LAN91C96
720 Support for SMSC's LAN91C96 chips.
723 Define this to hold the physical address
724 of the LAN91C96's I/O space
726 CONFIG_LAN91C96_USE_32_BIT
727 Define this to enable 32 bit addressing
730 At the moment only the UHCI host controller is
731 supported (PIP405, MIP405); define
732 CONFIG_USB_UHCI to enable it.
733 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
734 end define CONFIG_USB_STORAGE to enable the USB
737 Supported are USB Keyboards and USB Floppy drives
741 The MMC controller on the Intel PXA is supported. To
742 enable this define CONFIG_MMC. The MMC can be
743 accessed from the boot prompt by mapping the device
744 to physical memory similar to flash. Command line is
745 enabled with CFG_CMD_MMC. The MMC driver also works with
746 the FAT fs. This is enabled with CFG_CMD_FAT.
751 Define this to enable standard (PC-Style) keyboard
755 Standard PC keyboard driver with US (is default) and
756 GERMAN key layout (switch via environment 'keymap=de') support.
757 Export function i8042_kbd_init, i8042_tstc and i8042_getc
758 for cfb_console. Supports cursor blinking.
763 Define this to enable video support (for output to
768 Enable Chips & Technologies 69000 Video chip
770 CONFIG_VIDEO_SMI_LYNXEM
771 Enable Silicon Motion SMI 712/710/810 Video chip
772 Videomode are selected via environment 'videomode' with
773 standard LiLo mode numbers.
774 Following modes are supported (* is default):
776 800x600 1024x768 1280x1024
777 256 (8bit) 303* 305 307
778 65536 (16bit) 314 317 31a
779 16,7 Mill (24bit) 315 318 31b
780 (i.e. setenv videomode 317; saveenv; reset;)
782 CONFIG_VIDEO_SED13806
783 Enable Epson SED13806 driver. This driver supports 8bpp
784 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
785 or CONFIG_VIDEO_SED13806_16BPP
790 Define this to enable a custom keyboard support.
791 This simply calls drv_keyboard_init() which must be
792 defined in your board-specific files.
793 The only board using this so far is RBC823.
795 - LCD Support: CONFIG_LCD
797 Define this to enable LCD support (for output to LCD
798 display); also select one of the supported displays
799 by defining one of these:
801 CONFIG_NEC_NL6448AC33:
803 NEC NL6448AC33-18. Active, color, single scan.
805 CONFIG_NEC_NL6448BC20
807 NEC NL6448BC20-08. 6.5", 640x480.
808 Active, color, single scan.
810 CONFIG_NEC_NL6448BC33_54
812 NEC NL6448BC33-54. 10.4", 640x480.
813 Active, color, single scan.
817 Sharp 320x240. Active, color, single scan.
818 It isn't 16x9, and I am not sure what it is.
820 CONFIG_SHARP_LQ64D341
822 Sharp LQ64D341 display, 640x480.
823 Active, color, single scan.
827 HLD1045 display, 640x480.
828 Active, color, single scan.
832 Optrex CBL50840-2 NF-FW 99 22 M5
834 Hitachi LMG6912RPFC-00T
838 320x240. Black & white.
840 Normally display is black on white background; define
841 CFG_WHITE_ON_BLACK to get it inverted.
843 - Splash Screen Support: CONFIG_SPLASH_SCREEN
845 If this option is set, the environment is checked for
846 a variable "splashimage". If found, the usual display
847 of logo, copyright and system information on the LCD
848 is supressed and the BMP image at the address
849 specified in "splashimage" is loaded instead. The
850 console is redirected to the "nulldev", too. This
851 allows for a "silent" boot where a splash screen is
852 loaded very quickly after power-on.
854 - Compression support:
857 If this option is set, support for bzip2 compressed
858 images is included. If not, only uncompressed and gzip
859 compressed images are supported.
861 NOTE: the bzip2 algorithm requires a lot of RAM, so
862 the malloc area (as defined by CFG_MALLOC_LEN) should
870 Define a default value for ethernet address to use
871 for the respective ethernet interface, in case this
872 is not determined automatically.
877 Define a default value for the IP address to use for
878 the default ethernet interface, in case this is not
879 determined through e.g. bootp.
884 Defines a default value for theIP address of a TFTP
885 server to contact when using the "tftboot" command.
887 - BOOTP Recovery Mode:
888 CONFIG_BOOTP_RANDOM_DELAY
890 If you have many targets in a network that try to
891 boot using BOOTP, you may want to avoid that all
892 systems send out BOOTP requests at precisely the same
893 moment (which would happen for instance at recovery
894 from a power failure, when all systems will try to
895 boot, thus flooding the BOOTP server. Defining
896 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
897 inserted before sending out BOOTP requests. The
898 following delays are insterted then:
900 1st BOOTP request: delay 0 ... 1 sec
901 2nd BOOTP request: delay 0 ... 2 sec
902 3rd BOOTP request: delay 0 ... 4 sec
904 BOOTP requests: delay 0 ... 8 sec
906 - DHCP Advanced Options:
909 You can fine tune the DHCP functionality by adding
910 these flags to the CONFIG_BOOTP_MASK define:
912 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
913 serverip from a DHCP server, it is possible that more
914 than one DNS serverip is offered to the client.
915 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
916 serverip will be stored in the additional environment
917 variable "dnsip2". The first DNS serverip is always
918 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
919 is added to the CONFIG_BOOTP_MASK.
921 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
922 to do a dynamic update of a DNS server. To do this, they
923 need the hostname of the DHCP requester.
924 If CONFIG_BOOP_SEND_HOSTNAME is added to the
925 CONFIG_BOOTP_MASK, the content of the "hostname"
926 environment variable is passed as option 12 to
929 - Status LED: CONFIG_STATUS_LED
931 Several configurations allow to display the current
932 status using a LED. For instance, the LED will blink
933 fast while running U-Boot code, stop blinking as
934 soon as a reply to a BOOTP request was received, and
935 start blinking slow once the Linux kernel is running
936 (supported by a status LED driver in the Linux
937 kernel). Defining CONFIG_STATUS_LED enables this
940 - CAN Support: CONFIG_CAN_DRIVER
942 Defining CONFIG_CAN_DRIVER enables CAN driver support
943 on those systems that support this (optional)
944 feature, like the TQM8xxL modules.
946 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
948 These enable I2C serial bus commands. Defining either of
949 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
950 include the appropriate I2C driver for the selected cpu.
952 This will allow you to use i2c commands at the u-boot
953 command line (as long as you set CFG_CMD_I2C in
954 CONFIG_COMMANDS) and communicate with i2c based realtime
955 clock chips. See common/cmd_i2c.c for a description of the
956 command line interface.
958 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
960 CONFIG_SOFT_I2C configures u-boot to use a software (aka
961 bit-banging) driver instead of CPM or similar hardware
964 There are several other quantities that must also be
965 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
967 In both cases you will need to define CFG_I2C_SPEED
968 to be the frequency (in Hz) at which you wish your i2c bus
969 to run and CFG_I2C_SLAVE to be the address of this node (ie
970 the cpu's i2c node address).
972 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
973 sets the cpu up as a master node and so its address should
974 therefore be cleared to 0 (See, eg, MPC823e User's Manual
975 p.16-473). So, set CFG_I2C_SLAVE to 0.
977 That's all that's required for CONFIG_HARD_I2C.
979 If you use the software i2c interface (CONFIG_SOFT_I2C)
980 then the following macros need to be defined (examples are
981 from include/configs/lwmon.h):
985 (Optional). Any commands necessary to enable the I2C
986 controller or configure ports.
988 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
992 (Only for MPC8260 CPU). The I/O port to use (the code
993 assumes both bits are on the same port). Valid values
994 are 0..3 for ports A..D.
998 The code necessary to make the I2C data line active
999 (driven). If the data line is open collector, this
1002 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1006 The code necessary to make the I2C data line tri-stated
1007 (inactive). If the data line is open collector, this
1010 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1014 Code that returns TRUE if the I2C data line is high,
1017 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1021 If <bit> is TRUE, sets the I2C data line high. If it
1022 is FALSE, it clears it (low).
1024 eg: #define I2C_SDA(bit) \
1025 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1026 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1030 If <bit> is TRUE, sets the I2C clock line high. If it
1031 is FALSE, it clears it (low).
1033 eg: #define I2C_SCL(bit) \
1034 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1035 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1039 This delay is invoked four times per clock cycle so this
1040 controls the rate of data transfer. The data rate thus
1041 is 1 / (I2C_DELAY * 4). Often defined to be something
1044 #define I2C_DELAY udelay(2)
1048 When a board is reset during an i2c bus transfer
1049 chips might think that the current transfer is still
1050 in progress. On some boards it is possible to access
1051 the i2c SCLK line directly, either by using the
1052 processor pin as a GPIO or by having a second pin
1053 connected to the bus. If this option is defined a
1054 custom i2c_init_board() routine in boards/xxx/board.c
1055 is run early in the boot sequence.
1057 - SPI Support: CONFIG_SPI
1059 Enables SPI driver (so far only tested with
1060 SPI EEPROM, also an instance works with Crystal A/D and
1061 D/As on the SACSng board)
1065 Enables extended (16-bit) SPI EEPROM addressing.
1066 (symmetrical to CONFIG_I2C_X)
1070 Enables a software (bit-bang) SPI driver rather than
1071 using hardware support. This is a general purpose
1072 driver that only requires three general I/O port pins
1073 (two outputs, one input) to function. If this is
1074 defined, the board configuration must define several
1075 SPI configuration items (port pins to use, etc). For
1076 an example, see include/configs/sacsng.h.
1078 - FPGA Support: CONFIG_FPGA_COUNT
1080 Specify the number of FPGA devices to support.
1084 Used to specify the types of FPGA devices. For example,
1085 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1087 CFG_FPGA_PROG_FEEDBACK
1089 Enable printing of hash marks during FPGA configuration.
1093 Enable checks on FPGA configuration interface busy
1094 status by the configuration function. This option
1095 will require a board or device specific function to
1100 If defined, a function that provides delays in the FPGA
1101 configuration driver.
1103 CFG_FPGA_CHECK_CTRLC
1104 Allow Control-C to interrupt FPGA configuration
1106 CFG_FPGA_CHECK_ERROR
1108 Check for configuration errors during FPGA bitfile
1109 loading. For example, abort during Virtex II
1110 configuration if the INIT_B line goes low (which
1111 indicated a CRC error).
1115 Maximum time to wait for the INIT_B line to deassert
1116 after PROB_B has been deasserted during a Virtex II
1117 FPGA configuration sequence. The default time is 500
1122 Maximum time to wait for BUSY to deassert during
1123 Virtex II FPGA configuration. The default is 5 mS.
1125 CFG_FPGA_WAIT_CONFIG
1127 Time to wait after FPGA configuration. The default is
1130 - Configuration Management:
1133 If defined, this string will be added to the U-Boot
1134 version information (U_BOOT_VERSION)
1136 - Vendor Parameter Protection:
1138 U-Boot considers the values of the environment
1139 variables "serial#" (Board Serial Number) and
1140 "ethaddr" (Ethernet Address) to be parameters that
1141 are set once by the board vendor / manufacturer, and
1142 protects these variables from casual modification by
1143 the user. Once set, these variables are read-only,
1144 and write or delete attempts are rejected. You can
1145 change this behviour:
1147 If CONFIG_ENV_OVERWRITE is #defined in your config
1148 file, the write protection for vendor parameters is
1149 completely disabled. Anybody can change or delete
1152 Alternatively, if you #define _both_ CONFIG_ETHADDR
1153 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1154 ethernet address is installed in the environment,
1155 which can be changed exactly ONCE by the user. [The
1156 serial# is unaffected by this, i. e. it remains
1162 Define this variable to enable the reservation of
1163 "protected RAM", i. e. RAM which is not overwritten
1164 by U-Boot. Define CONFIG_PRAM to hold the number of
1165 kB you want to reserve for pRAM. You can overwrite
1166 this default value by defining an environment
1167 variable "pram" to the number of kB you want to
1168 reserve. Note that the board info structure will
1169 still show the full amount of RAM. If pRAM is
1170 reserved, a new environment variable "mem" will
1171 automatically be defined to hold the amount of
1172 remaining RAM in a form that can be passed as boot
1173 argument to Linux, for instance like that:
1175 setenv bootargs ... mem=\$(mem)
1178 This way you can tell Linux not to use this memory,
1179 either, which results in a memory region that will
1180 not be affected by reboots.
1182 *WARNING* If your board configuration uses automatic
1183 detection of the RAM size, you must make sure that
1184 this memory test is non-destructive. So far, the
1185 following board configurations are known to be
1188 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1189 HERMES, IP860, RPXlite, LWMON, LANTEC,
1190 PCU_E, FLAGADM, TQM8260
1195 Define this variable to stop the system in case of a
1196 fatal error, so that you have to reset it manually.
1197 This is probably NOT a good idea for an embedded
1198 system where you want to system to reboot
1199 automatically as fast as possible, but it may be
1200 useful during development since you can try to debug
1201 the conditions that lead to the situation.
1203 CONFIG_NET_RETRY_COUNT
1205 This variable defines the number of retries for
1206 network operations like ARP, RARP, TFTP, or BOOTP
1207 before giving up the operation. If not defined, a
1208 default value of 5 is used.
1210 - Command Interpreter:
1213 Define this variable to enable the "hush" shell (from
1214 Busybox) as command line interpreter, thus enabling
1215 powerful command line syntax like
1216 if...then...else...fi conditionals or `&&' and '||'
1217 constructs ("shell scripts").
1219 If undefined, you get the old, much simpler behaviour
1220 with a somewhat smaller memory footprint.
1225 This defines the secondary prompt string, which is
1226 printed when the command interpreter needs more input
1227 to complete a command. Usually "> ".
1231 In the current implementation, the local variables
1232 space and global environment variables space are
1233 separated. Local variables are those you define by
1234 simply typing `name=value'. To access a local
1235 variable later on, you have write `$name' or
1236 `${name}'; to execute the contents of a variable
1237 directly type `$name' at the command prompt.
1239 Global environment variables are those you use
1240 setenv/printenv to work with. To run a command stored
1241 in such a variable, you need to use the run command,
1242 and you must not use the '$' sign to access them.
1244 To store commands and special characters in a
1245 variable, please use double quotation marks
1246 surrounding the whole text of the variable, instead
1247 of the backslashes before semicolons and special
1250 - Default Environment:
1251 CONFIG_EXTRA_ENV_SETTINGS
1253 Define this to contain any number of null terminated
1254 strings (variable = value pairs) that will be part of
1255 the default environment compiled into the boot image.
1257 For example, place something like this in your
1258 board's config file:
1260 #define CONFIG_EXTRA_ENV_SETTINGS \
1264 Warning: This method is based on knowledge about the
1265 internal format how the environment is stored by the
1266 U-Boot code. This is NOT an official, exported
1267 interface! Although it is unlikely that this format
1268 will change soon, there is no guarantee either.
1269 You better know what you are doing here.
1271 Note: overly (ab)use of the default environment is
1272 discouraged. Make sure to check other ways to preset
1273 the environment like the autoscript function or the
1276 - DataFlash Support:
1277 CONFIG_HAS_DATAFLASH
1279 Defining this option enables DataFlash features and
1280 allows to read/write in Dataflash via the standard
1283 - SystemACE Support:
1286 Adding this option adds support for Xilinx SystemACE
1287 chips attached via some sort of local bus. The address
1288 of the chip must alsh be defined in the
1289 CFG_SYSTEMACE_BASE macro. For example:
1291 #define CONFIG_SYSTEMACE
1292 #define CFG_SYSTEMACE_BASE 0xf0000000
1294 When SystemACE support is added, the "ace" device type
1295 becomes available to the fat commands, i.e. fatls.
1297 - Show boot progress:
1298 CONFIG_SHOW_BOOT_PROGRESS
1300 Defining this option allows to add some board-
1301 specific code (calling a user-provided function
1302 "show_boot_progress(int)") that enables you to show
1303 the system's boot progress on some display (for
1304 example, some LED's) on your board. At the moment,
1305 the following checkpoints are implemented:
1308 1 common/cmd_bootm.c before attempting to boot an image
1309 -1 common/cmd_bootm.c Image header has bad magic number
1310 2 common/cmd_bootm.c Image header has correct magic number
1311 -2 common/cmd_bootm.c Image header has bad checksum
1312 3 common/cmd_bootm.c Image header has correct checksum
1313 -3 common/cmd_bootm.c Image data has bad checksum
1314 4 common/cmd_bootm.c Image data has correct checksum
1315 -4 common/cmd_bootm.c Image is for unsupported architecture
1316 5 common/cmd_bootm.c Architecture check OK
1317 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1318 6 common/cmd_bootm.c Image Type check OK
1319 -6 common/cmd_bootm.c gunzip uncompression error
1320 -7 common/cmd_bootm.c Unimplemented compression type
1321 7 common/cmd_bootm.c Uncompression OK
1322 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1323 8 common/cmd_bootm.c Image Type check OK
1324 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1325 9 common/cmd_bootm.c Start initial ramdisk verification
1326 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1327 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1328 10 common/cmd_bootm.c Ramdisk header is OK
1329 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1330 11 common/cmd_bootm.c Ramdisk data has correct checksum
1331 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1332 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1333 13 common/cmd_bootm.c Start multifile image verification
1334 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1335 15 common/cmd_bootm.c All preparation done, transferring control to OS
1337 -30 lib_ppc/board.c Fatal error, hang the system
1338 -31 post/post.c POST test failed, detected by post_output_backlog()
1339 -32 post/post.c POST test failed, detected by post_run_single()
1341 -1 common/cmd_doc.c Bad usage of "doc" command
1342 -1 common/cmd_doc.c No boot device
1343 -1 common/cmd_doc.c Unknown Chip ID on boot device
1344 -1 common/cmd_doc.c Read Error on boot device
1345 -1 common/cmd_doc.c Image header has bad magic number
1347 -1 common/cmd_ide.c Bad usage of "ide" command
1348 -1 common/cmd_ide.c No boot device
1349 -1 common/cmd_ide.c Unknown boot device
1350 -1 common/cmd_ide.c Unknown partition table
1351 -1 common/cmd_ide.c Invalid partition type
1352 -1 common/cmd_ide.c Read Error on boot device
1353 -1 common/cmd_ide.c Image header has bad magic number
1355 -1 common/cmd_nand.c Bad usage of "nand" command
1356 -1 common/cmd_nand.c No boot device
1357 -1 common/cmd_nand.c Unknown Chip ID on boot device
1358 -1 common/cmd_nand.c Read Error on boot device
1359 -1 common/cmd_nand.c Image header has bad magic number
1361 -1 common/env_common.c Environment has a bad CRC, using default
1367 [so far only for SMDK2400 and TRAB boards]
1369 - Modem support endable:
1370 CONFIG_MODEM_SUPPORT
1372 - RTS/CTS Flow control enable:
1375 - Modem debug support:
1376 CONFIG_MODEM_SUPPORT_DEBUG
1378 Enables debugging stuff (char screen[1024], dbg())
1379 for modem support. Useful only with BDI2000.
1381 - Interrupt support (PPC):
1383 There are common interrupt_init() and timer_interrupt()
1384 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1385 for cpu specific initialization. interrupt_init_cpu()
1386 should set decrementer_count to appropriate value. If
1387 cpu resets decrementer automatically after interrupt
1388 (ppc4xx) it should set decrementer_count to zero.
1389 timer_interrupt() calls timer_interrupt_cpu() for cpu
1390 specific handling. If board has watchdog / status_led
1391 / other_activity_monitor it works automatically from
1392 general timer_interrupt().
1396 In the target system modem support is enabled when a
1397 specific key (key combination) is pressed during
1398 power-on. Otherwise U-Boot will boot normally
1399 (autoboot). The key_pressed() fuction is called from
1400 board_init(). Currently key_pressed() is a dummy
1401 function, returning 1 and thus enabling modem
1404 If there are no modem init strings in the
1405 environment, U-Boot proceed to autoboot; the
1406 previous output (banner, info printfs) will be
1409 See also: doc/README.Modem
1412 Configuration Settings:
1413 -----------------------
1415 - CFG_LONGHELP: Defined when you want long help messages included;
1416 undefine this when you're short of memory.
1418 - CFG_PROMPT: This is what U-Boot prints on the console to
1419 prompt for user input.
1421 - CFG_CBSIZE: Buffer size for input from the Console
1423 - CFG_PBSIZE: Buffer size for Console output
1425 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1427 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1428 the application (usually a Linux kernel) when it is
1431 - CFG_BAUDRATE_TABLE:
1432 List of legal baudrate settings for this board.
1434 - CFG_CONSOLE_INFO_QUIET
1435 Suppress display of console information at boot.
1437 - CFG_CONSOLE_IS_IN_ENV
1438 If the board specific function
1439 extern int overwrite_console (void);
1440 returns 1, the stdin, stderr and stdout are switched to the
1441 serial port, else the settings in the environment are used.
1443 - CFG_CONSOLE_OVERWRITE_ROUTINE
1444 Enable the call to overwrite_console().
1446 - CFG_CONSOLE_ENV_OVERWRITE
1447 Enable overwrite of previous console environment settings.
1449 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1450 Begin and End addresses of the area used by the
1454 Enable an alternate, more extensive memory test.
1456 - CFG_MEMTEST_SCRATCH:
1457 Scratch address used by the alternate memory test
1458 You only need to set this if address zero isn't writeable
1460 - CFG_TFTP_LOADADDR:
1461 Default load address for network file downloads
1463 - CFG_LOADS_BAUD_CHANGE:
1464 Enable temporary baudrate change while serial download
1467 Physical start address of SDRAM. _Must_ be 0 here.
1470 Physical start address of Motherboard I/O (if using a
1474 Physical start address of Flash memory.
1477 Physical start address of boot monitor code (set by
1478 make config files to be same as the text base address
1479 (TEXT_BASE) used when linking) - same as
1480 CFG_FLASH_BASE when booting from flash.
1483 Size of memory reserved for monitor code, used to
1484 determine _at_compile_time_ (!) if the environment is
1485 embedded within the U-Boot image, or in a separate
1489 Size of DRAM reserved for malloc() use.
1492 Maximum size of memory mapped by the startup code of
1493 the Linux kernel; all data that must be processed by
1494 the Linux kernel (bd_info, boot arguments, eventually
1495 initrd image) must be put below this limit.
1497 - CFG_MAX_FLASH_BANKS:
1498 Max number of Flash memory banks
1500 - CFG_MAX_FLASH_SECT:
1501 Max number of sectors on a Flash chip
1503 - CFG_FLASH_ERASE_TOUT:
1504 Timeout for Flash erase operations (in ms)
1506 - CFG_FLASH_WRITE_TOUT:
1507 Timeout for Flash write operations (in ms)
1509 - CFG_FLASH_LOCK_TOUT
1510 Timeout for Flash set sector lock bit operation (in ms)
1512 - CFG_FLASH_UNLOCK_TOUT
1513 Timeout for Flash clear lock bits operation (in ms)
1515 - CFG_FLASH_PROTECTION
1516 If defined, hardware flash sectors protection is used
1517 instead of U-Boot software protection.
1519 - CFG_DIRECT_FLASH_TFTP:
1521 Enable TFTP transfers directly to flash memory;
1522 without this option such a download has to be
1523 performed in two steps: (1) download to RAM, and (2)
1524 copy from RAM to flash.
1526 The two-step approach is usually more reliable, since
1527 you can check if the download worked before you erase
1528 the flash, but in some situations (when sytem RAM is
1529 too limited to allow for a tempory copy of the
1530 downloaded image) this option may be very useful.
1533 Define if the flash driver uses extra elements in the
1534 common flash structure for storing flash geometry.
1536 - CFG_FLASH_CFI_DRIVER
1537 This option also enables the building of the cfi_flash driver
1538 in the drivers directory
1540 - CFG_RX_ETH_BUFFER:
1541 Defines the number of ethernet receive buffers. On some
1542 ethernet controllers it is recommended to set this value
1543 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1544 buffers can be full shortly after enabling the interface
1545 on high ethernet traffic.
1546 Defaults to 4 if not defined.
1548 The following definitions that deal with the placement and management
1549 of environment data (variable area); in general, we support the
1550 following configurations:
1552 - CFG_ENV_IS_IN_FLASH:
1554 Define this if the environment is in flash memory.
1556 a) The environment occupies one whole flash sector, which is
1557 "embedded" in the text segment with the U-Boot code. This
1558 happens usually with "bottom boot sector" or "top boot
1559 sector" type flash chips, which have several smaller
1560 sectors at the start or the end. For instance, such a
1561 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1562 such a case you would place the environment in one of the
1563 4 kB sectors - with U-Boot code before and after it. With
1564 "top boot sector" type flash chips, you would put the
1565 environment in one of the last sectors, leaving a gap
1566 between U-Boot and the environment.
1570 Offset of environment data (variable area) to the
1571 beginning of flash memory; for instance, with bottom boot
1572 type flash chips the second sector can be used: the offset
1573 for this sector is given here.
1575 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1579 This is just another way to specify the start address of
1580 the flash sector containing the environment (instead of
1583 - CFG_ENV_SECT_SIZE:
1585 Size of the sector containing the environment.
1588 b) Sometimes flash chips have few, equal sized, BIG sectors.
1589 In such a case you don't want to spend a whole sector for
1594 If you use this in combination with CFG_ENV_IS_IN_FLASH
1595 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1596 of this flash sector for the environment. This saves
1597 memory for the RAM copy of the environment.
1599 It may also save flash memory if you decide to use this
1600 when your environment is "embedded" within U-Boot code,
1601 since then the remainder of the flash sector could be used
1602 for U-Boot code. It should be pointed out that this is
1603 STRONGLY DISCOURAGED from a robustness point of view:
1604 updating the environment in flash makes it always
1605 necessary to erase the WHOLE sector. If something goes
1606 wrong before the contents has been restored from a copy in
1607 RAM, your target system will be dead.
1609 - CFG_ENV_ADDR_REDUND
1612 These settings describe a second storage area used to hold
1613 a redundand copy of the environment data, so that there is
1614 a valid backup copy in case there is a power failure during
1615 a "saveenv" operation.
1617 BE CAREFUL! Any changes to the flash layout, and some changes to the
1618 source code will make it necessary to adapt <board>/u-boot.lds*
1622 - CFG_ENV_IS_IN_NVRAM:
1624 Define this if you have some non-volatile memory device
1625 (NVRAM, battery buffered SRAM) which you want to use for the
1631 These two #defines are used to determin the memory area you
1632 want to use for environment. It is assumed that this memory
1633 can just be read and written to, without any special
1636 BE CAREFUL! The first access to the environment happens quite early
1637 in U-Boot initalization (when we try to get the setting of for the
1638 console baudrate). You *MUST* have mappend your NVRAM area then, or
1641 Please note that even with NVRAM we still use a copy of the
1642 environment in RAM: we could work on NVRAM directly, but we want to
1643 keep settings there always unmodified except somebody uses "saveenv"
1644 to save the current settings.
1647 - CFG_ENV_IS_IN_EEPROM:
1649 Use this if you have an EEPROM or similar serial access
1650 device and a driver for it.
1655 These two #defines specify the offset and size of the
1656 environment area within the total memory of your EEPROM.
1658 - CFG_I2C_EEPROM_ADDR:
1659 If defined, specified the chip address of the EEPROM device.
1660 The default address is zero.
1662 - CFG_EEPROM_PAGE_WRITE_BITS:
1663 If defined, the number of bits used to address bytes in a
1664 single page in the EEPROM device. A 64 byte page, for example
1665 would require six bits.
1667 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
1668 If defined, the number of milliseconds to delay between
1669 page writes. The default is zero milliseconds.
1671 - CFG_I2C_EEPROM_ADDR_LEN:
1672 The length in bytes of the EEPROM memory array address. Note
1673 that this is NOT the chip address length!
1676 The size in bytes of the EEPROM device.
1679 - CFG_ENV_IS_IN_DATAFLASH:
1681 Define this if you have a DataFlash memory device which you
1682 want to use for the environment.
1688 These three #defines specify the offset and size of the
1689 environment area within the total memory of your DataFlash placed
1690 at the specified address.
1693 - CFG_SPI_INIT_OFFSET
1695 Defines offset to the initial SPI buffer area in DPRAM. The
1696 area is used at an early stage (ROM part) if the environment
1697 is configured to reside in the SPI EEPROM: We need a 520 byte
1698 scratch DPRAM area. It is used between the two initialization
1699 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
1700 to be a good choice since it makes it far enough from the
1701 start of the data area as well as from the stack pointer.
1703 Please note that the environment is read-only as long as the monitor
1704 has been relocated to RAM and a RAM copy of the environment has been
1705 created; also, when using EEPROM you will have to use getenv_r()
1706 until then to read environment variables.
1708 The environment is protected by a CRC32 checksum. Before the monitor
1709 is relocated into RAM, as a result of a bad CRC you will be working
1710 with the compiled-in default environment - *silently*!!! [This is
1711 necessary, because the first environment variable we need is the
1712 "baudrate" setting for the console - if we have a bad CRC, we don't
1713 have any device yet where we could complain.]
1715 Note: once the monitor has been relocated, then it will complain if
1716 the default environment is used; a new CRC is computed as soon as you
1717 use the "saveenv" command to store a valid environment.
1719 - CFG_FAULT_ECHO_LINK_DOWN:
1720 Echo the inverted Ethernet link state to the fault LED.
1722 Note: If this option is active, then CFG_FAULT_MII_ADDR
1723 also needs to be defined.
1725 - CFG_FAULT_MII_ADDR:
1726 MII address of the PHY to check for the Ethernet link state.
1728 - CFG_64BIT_VSPRINTF:
1729 Makes vsprintf (and all *printf functions) support printing
1730 of 64bit values by using the L quantifier
1732 - CFG_64BIT_STRTOUL:
1733 Adds simple_strtoull that returns a 64bit value
1735 Low Level (hardware related) configuration options:
1736 ---------------------------------------------------
1738 - CFG_CACHELINE_SIZE:
1739 Cache Line Size of the CPU.
1742 Default address of the IMMR after system reset.
1744 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
1745 and RPXsuper) to be able to adjust the position of
1746 the IMMR register after a reset.
1748 - Floppy Disk Support:
1749 CFG_FDC_DRIVE_NUMBER
1751 the default drive number (default value 0)
1755 defines the spacing between fdc chipset registers
1760 defines the offset of register from address. It
1761 depends on which part of the data bus is connected to
1762 the fdc chipset. (default value 0)
1764 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
1765 CFG_FDC_DRIVE_NUMBER are undefined, they take their
1768 if CFG_FDC_HW_INIT is defined, then the function
1769 fdc_hw_init() is called at the beginning of the FDC
1770 setup. fdc_hw_init() must be provided by the board
1771 source code. It is used to make hardware dependant
1774 - CFG_IMMR: Physical address of the Internal Memory Mapped
1775 Register; DO NOT CHANGE! (11-4)
1776 [MPC8xx systems only]
1778 - CFG_INIT_RAM_ADDR:
1780 Start address of memory area that can be used for
1781 initial data and stack; please note that this must be
1782 writable memory that is working WITHOUT special
1783 initialization, i. e. you CANNOT use normal RAM which
1784 will become available only after programming the
1785 memory controller and running certain initialization
1788 U-Boot uses the following memory types:
1789 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
1790 - MPC824X: data cache
1791 - PPC4xx: data cache
1793 - CFG_GBL_DATA_OFFSET:
1795 Offset of the initial data structure in the memory
1796 area defined by CFG_INIT_RAM_ADDR. Usually
1797 CFG_GBL_DATA_OFFSET is chosen such that the initial
1798 data is located at the end of the available space
1799 (sometimes written as (CFG_INIT_RAM_END -
1800 CFG_INIT_DATA_SIZE), and the initial stack is just
1801 below that area (growing from (CFG_INIT_RAM_ADDR +
1802 CFG_GBL_DATA_OFFSET) downward.
1805 On the MPC824X (or other systems that use the data
1806 cache for initial memory) the address chosen for
1807 CFG_INIT_RAM_ADDR is basically arbitrary - it must
1808 point to an otherwise UNUSED address space between
1809 the top of RAM and the start of the PCI space.
1811 - CFG_SIUMCR: SIU Module Configuration (11-6)
1813 - CFG_SYPCR: System Protection Control (11-9)
1815 - CFG_TBSCR: Time Base Status and Control (11-26)
1817 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
1819 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
1821 - CFG_SCCR: System Clock and reset Control Register (15-27)
1823 - CFG_OR_TIMING_SDRAM:
1827 periodic timer for refresh
1829 - CFG_DER: Debug Event Register (37-47)
1831 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
1832 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
1833 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
1835 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
1837 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
1838 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
1839 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
1840 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
1842 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
1843 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
1844 Machine Mode Register and Memory Periodic Timer
1845 Prescaler definitions (SDRAM timing)
1847 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
1848 enable I2C microcode relocation patch (MPC8xx);
1849 define relocation offset in DPRAM [DSP2]
1851 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
1852 enable SPI microcode relocation patch (MPC8xx);
1853 define relocation offset in DPRAM [SCC4]
1856 Use OSCM clock mode on MBX8xx board. Be careful,
1857 wrong setting might damage your board. Read
1858 doc/README.MBX before setting this variable!
1860 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
1861 Offset of the bootmode word in DPRAM used by post
1862 (Power On Self Tests). This definition overrides
1863 #define'd default value in commproc.h resp.
1866 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
1867 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
1868 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
1869 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
1870 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
1871 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
1872 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
1873 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
1874 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
1876 Building the Software:
1877 ======================
1879 Building U-Boot has been tested in native PPC environments (on a
1880 PowerBook G3 running LinuxPPC 2000) and in cross environments
1881 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
1884 If you are not using a native PPC environment, it is assumed that you
1885 have the GNU cross compiling tools available in your path and named
1886 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
1887 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
1888 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
1891 CROSS_COMPILE = ppc_4xx-
1894 U-Boot is intended to be simple to build. After installing the
1895 sources you must configure U-Boot for one specific board type. This
1900 where "NAME_config" is the name of one of the existing
1901 configurations; the following names are supported:
1903 ADCIOP_config GTH_config TQM850L_config
1904 ADS860_config IP860_config TQM855L_config
1905 AR405_config IVML24_config TQM860L_config
1906 CANBT_config IVMS8_config WALNUT405_config
1907 CPCI405_config LANTEC_config cogent_common_config
1908 CPCIISER4_config MBX_config cogent_mpc8260_config
1909 CU824_config MBX860T_config cogent_mpc8xx_config
1910 ESTEEM192E_config RPXlite_config hermes_config
1911 ETX094_config RPXsuper_config hymod_config
1912 FADS823_config SM850_config lwmon_config
1913 FADS850SAR_config SPD823TS_config pcu_e_config
1914 FADS860T_config SXNI855T_config rsdproto_config
1915 FPS850L_config Sandpoint8240_config sbc8260_config
1916 GENIETV_config TQM823L_config PIP405_config
1917 GEN860T_config EBONY_config FPS860L_config
1918 ELPT860_config cmi_mpc5xx_config NETVIA_config
1919 at91rm9200dk_config omap1510inn_config MPC8260ADS_config
1920 omap1610inn_config ZPC1900_config MPC8540ADS_config
1921 MPC8560ADS_config QS850_config QS823_config
1922 QS860T_config DUET_ADS_config omap1610h2_config
1924 Note: for some board special configuration names may exist; check if
1925 additional information is available from the board vendor; for
1926 instance, the TQM8xxL systems run normally at 50 MHz and use a
1927 SCC for 10baseT ethernet; there are also systems with 80 MHz
1928 CPU clock, and an optional Fast Ethernet module is available
1929 for CPU's with FEC. You can select such additional "features"
1930 when chosing the configuration, i. e.
1933 - will configure for a plain TQM860L, i. e. 50MHz, no FEC
1935 make TQM860L_FEC_config
1936 - will configure for a TQM860L at 50MHz with FEC for ethernet
1938 make TQM860L_80MHz_config
1939 - will configure for a TQM860L at 80 MHz, with normal 10baseT
1942 make TQM860L_FEC_80MHz_config
1943 - will configure for a TQM860L at 80 MHz with FEC for ethernet
1945 make TQM823L_LCD_config
1946 - will configure for a TQM823L with U-Boot console on LCD
1948 make TQM823L_LCD_80MHz_config
1949 - will configure for a TQM823L at 80 MHz with U-Boot console on LCD
1954 Finally, type "make all", and you should get some working U-Boot
1955 images ready for download to / installation on your system:
1957 - "u-boot.bin" is a raw binary image
1958 - "u-boot" is an image in ELF binary format
1959 - "u-boot.srec" is in Motorola S-Record format
1962 Please be aware that the Makefiles assume you are using GNU make, so
1963 for instance on NetBSD you might need to use "gmake" instead of
1967 If the system board that you have is not listed, then you will need
1968 to port U-Boot to your hardware platform. To do this, follow these
1971 1. Add a new configuration option for your board to the toplevel
1972 "Makefile" and to the "MAKEALL" script, using the existing
1973 entries as examples. Note that here and at many other places
1974 boards and other names are listed in alphabetical sort order. Please
1976 2. Create a new directory to hold your board specific code. Add any
1977 files you need. In your board directory, you will need at least
1978 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
1979 3. Create a new configuration file "include/configs/<board>.h" for
1981 3. If you're porting U-Boot to a new CPU, then also create a new
1982 directory to hold your CPU specific code. Add any files you need.
1983 4. Run "make <board>_config" with your new name.
1984 5. Type "make", and you should get a working "u-boot.srec" file
1985 to be installed on your target system.
1986 6. Debug and solve any problems that might arise.
1987 [Of course, this last step is much harder than it sounds.]
1990 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
1991 ==============================================================
1993 If you have modified U-Boot sources (for instance added a new board
1994 or support for new devices, a new CPU, etc.) you are expected to
1995 provide feedback to the other developers. The feedback normally takes
1996 the form of a "patch", i. e. a context diff against a certain (latest
1997 official or latest in CVS) version of U-Boot sources.
1999 But before you submit such a patch, please verify that your modifi-
2000 cation did not break existing code. At least make sure that *ALL* of
2001 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2002 just run the "MAKEALL" script, which will configure and build U-Boot
2003 for ALL supported system. Be warned, this will take a while. You can
2004 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2005 environment variable to the script, i. e. to use the cross tools from
2006 MontaVista's Hard Hat Linux you can type
2008 CROSS_COMPILE=ppc_8xx- MAKEALL
2010 or to build on a native PowerPC system you can type
2012 CROSS_COMPILE=' ' MAKEALL
2014 See also "U-Boot Porting Guide" below.
2017 Monitor Commands - Overview:
2018 ============================
2020 go - start application at address 'addr'
2021 run - run commands in an environment variable
2022 bootm - boot application image from memory
2023 bootp - boot image via network using BootP/TFTP protocol
2024 tftpboot- boot image via network using TFTP protocol
2025 and env variables "ipaddr" and "serverip"
2026 (and eventually "gatewayip")
2027 rarpboot- boot image via network using RARP/TFTP protocol
2028 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2029 loads - load S-Record file over serial line
2030 loadb - load binary file over serial line (kermit mode)
2032 mm - memory modify (auto-incrementing)
2033 nm - memory modify (constant address)
2034 mw - memory write (fill)
2036 cmp - memory compare
2037 crc32 - checksum calculation
2038 imd - i2c memory display
2039 imm - i2c memory modify (auto-incrementing)
2040 inm - i2c memory modify (constant address)
2041 imw - i2c memory write (fill)
2042 icrc32 - i2c checksum calculation
2043 iprobe - probe to discover valid I2C chip addresses
2044 iloop - infinite loop on address range
2045 isdram - print SDRAM configuration information
2046 sspi - SPI utility commands
2047 base - print or set address offset
2048 printenv- print environment variables
2049 setenv - set environment variables
2050 saveenv - save environment variables to persistent storage
2051 protect - enable or disable FLASH write protection
2052 erase - erase FLASH memory
2053 flinfo - print FLASH memory information
2054 bdinfo - print Board Info structure
2055 iminfo - print header information for application image
2056 coninfo - print console devices and informations
2057 ide - IDE sub-system
2058 loop - infinite loop on address range
2059 mtest - simple RAM test
2060 icache - enable or disable instruction cache
2061 dcache - enable or disable data cache
2062 reset - Perform RESET of the CPU
2063 echo - echo args to console
2064 version - print monitor version
2065 help - print online help
2066 ? - alias for 'help'
2069 Monitor Commands - Detailed Description:
2070 ========================================
2074 For now: just type "help <command>".
2077 Environment Variables:
2078 ======================
2080 U-Boot supports user configuration using Environment Variables which
2081 can be made persistent by saving to Flash memory.
2083 Environment Variables are set using "setenv", printed using
2084 "printenv", and saved to Flash using "saveenv". Using "setenv"
2085 without a value can be used to delete a variable from the
2086 environment. As long as you don't save the environment you are
2087 working with an in-memory copy. In case the Flash area containing the
2088 environment is erased by accident, a default environment is provided.
2090 Some configuration options can be set using Environment Variables:
2092 baudrate - see CONFIG_BAUDRATE
2094 bootdelay - see CONFIG_BOOTDELAY
2096 bootcmd - see CONFIG_BOOTCOMMAND
2098 bootargs - Boot arguments when booting an RTOS image
2100 bootfile - Name of the image to load with TFTP
2102 autoload - if set to "no" (any string beginning with 'n'),
2103 "bootp" will just load perform a lookup of the
2104 configuration from the BOOTP server, but not try to
2105 load any image using TFTP
2107 autostart - if set to "yes", an image loaded using the "bootp",
2108 "rarpboot", "tftpboot" or "diskboot" commands will
2109 be automatically started (by internally calling
2112 If set to "no", a standalone image passed to the
2113 "bootm" command will be copied to the load address
2114 (and eventually uncompressed), but NOT be started.
2115 This can be used to load and uncompress arbitrary
2118 initrd_high - restrict positioning of initrd images:
2119 If this variable is not set, initrd images will be
2120 copied to the highest possible address in RAM; this
2121 is usually what you want since it allows for
2122 maximum initrd size. If for some reason you want to
2123 make sure that the initrd image is loaded below the
2124 CFG_BOOTMAPSZ limit, you can set this environment
2125 variable to a value of "no" or "off" or "0".
2126 Alternatively, you can set it to a maximum upper
2127 address to use (U-Boot will still check that it
2128 does not overwrite the U-Boot stack and data).
2130 For instance, when you have a system with 16 MB
2131 RAM, and want to reserve 4 MB from use by Linux,
2132 you can do this by adding "mem=12M" to the value of
2133 the "bootargs" variable. However, now you must make
2134 sure that the initrd image is placed in the first
2135 12 MB as well - this can be done with
2137 setenv initrd_high 00c00000
2139 If you set initrd_high to 0xFFFFFFFF, this is an
2140 indication to U-Boot that all addresses are legal
2141 for the Linux kernel, including addresses in flash
2142 memory. In this case U-Boot will NOT COPY the
2143 ramdisk at all. This may be useful to reduce the
2144 boot time on your system, but requires that this
2145 feature is supported by your Linux kernel.
2147 ipaddr - IP address; needed for tftpboot command
2149 loadaddr - Default load address for commands like "bootp",
2150 "rarpboot", "tftpboot", "loadb" or "diskboot"
2152 loads_echo - see CONFIG_LOADS_ECHO
2154 serverip - TFTP server IP address; needed for tftpboot command
2156 bootretry - see CONFIG_BOOT_RETRY_TIME
2158 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2160 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2163 The following environment variables may be used and automatically
2164 updated by the network boot commands ("bootp" and "rarpboot"),
2165 depending the information provided by your boot server:
2167 bootfile - see above
2168 dnsip - IP address of your Domain Name Server
2169 dnsip2 - IP address of your secondary Domain Name Server
2170 gatewayip - IP address of the Gateway (Router) to use
2171 hostname - Target hostname
2173 netmask - Subnet Mask
2174 rootpath - Pathname of the root filesystem on the NFS server
2175 serverip - see above
2178 There are two special Environment Variables:
2180 serial# - contains hardware identification information such
2181 as type string and/or serial number
2182 ethaddr - Ethernet address
2184 These variables can be set only once (usually during manufacturing of
2185 the board). U-Boot refuses to delete or overwrite these variables
2186 once they have been set once.
2189 Further special Environment Variables:
2191 ver - Contains the U-Boot version string as printed
2192 with the "version" command. This variable is
2193 readonly (see CONFIG_VERSION_VARIABLE).
2196 Please note that changes to some configuration parameters may take
2197 only effect after the next boot (yes, that's just like Windoze :-).
2200 Command Line Parsing:
2201 =====================
2203 There are two different command line parsers available with U-Boot:
2204 the old "simple" one, and the much more powerful "hush" shell:
2206 Old, simple command line parser:
2207 --------------------------------
2209 - supports environment variables (through setenv / saveenv commands)
2210 - several commands on one line, separated by ';'
2211 - variable substitution using "... $(name) ..." syntax
2212 - special characters ('$', ';') can be escaped by prefixing with '\',
2214 setenv bootcmd bootm \$(address)
2215 - You can also escape text by enclosing in single apostrophes, for example:
2216 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2221 - similar to Bourne shell, with control structures like
2222 if...then...else...fi, for...do...done; while...do...done,
2223 until...do...done, ...
2224 - supports environment ("global") variables (through setenv / saveenv
2225 commands) and local shell variables (through standard shell syntax
2226 "name=value"); only environment variables can be used with "run"
2232 (1) If a command line (or an environment variable executed by a "run"
2233 command) contains several commands separated by semicolon, and
2234 one of these commands fails, then the remaining commands will be
2237 (2) If you execute several variables with one call to run (i. e.
2238 calling run with a list af variables as arguments), any failing
2239 command will cause "run" to terminate, i. e. the remaining
2240 variables are not executed.
2242 Note for Redundant Ethernet Interfaces:
2243 =======================================
2245 Some boards come with redundant ethernet interfaces; U-Boot supports
2246 such configurations and is capable of automatic selection of a
2247 "working" interface when needed. MAC assignment works as follows:
2249 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2250 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2251 "eth1addr" (=>eth1), "eth2addr", ...
2253 If the network interface stores some valid MAC address (for instance
2254 in SROM), this is used as default address if there is NO correspon-
2255 ding setting in the environment; if the corresponding environment
2256 variable is set, this overrides the settings in the card; that means:
2258 o If the SROM has a valid MAC address, and there is no address in the
2259 environment, the SROM's address is used.
2261 o If there is no valid address in the SROM, and a definition in the
2262 environment exists, then the value from the environment variable is
2265 o If both the SROM and the environment contain a MAC address, and
2266 both addresses are the same, this MAC address is used.
2268 o If both the SROM and the environment contain a MAC address, and the
2269 addresses differ, the value from the environment is used and a
2272 o If neither SROM nor the environment contain a MAC address, an error
2279 The "boot" commands of this monitor operate on "image" files which
2280 can be basicly anything, preceeded by a special header; see the
2281 definitions in include/image.h for details; basicly, the header
2282 defines the following image properties:
2284 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2285 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2286 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2287 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2288 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
2289 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2290 Currently supported: ARM, Intel x86, MIPS, NIOS, PowerPC).
2291 * Compression Type (uncompressed, gzip, bzip2)
2297 The header is marked by a special Magic Number, and both the header
2298 and the data portions of the image are secured against corruption by
2305 Although U-Boot should support any OS or standalone application
2306 easily, the main focus has always been on Linux during the design of
2309 U-Boot includes many features that so far have been part of some
2310 special "boot loader" code within the Linux kernel. Also, any
2311 "initrd" images to be used are no longer part of one big Linux image;
2312 instead, kernel and "initrd" are separate images. This implementation
2313 serves several purposes:
2315 - the same features can be used for other OS or standalone
2316 applications (for instance: using compressed images to reduce the
2317 Flash memory footprint)
2319 - it becomes much easier to port new Linux kernel versions because
2320 lots of low-level, hardware dependent stuff are done by U-Boot
2322 - the same Linux kernel image can now be used with different "initrd"
2323 images; of course this also means that different kernel images can
2324 be run with the same "initrd". This makes testing easier (you don't
2325 have to build a new "zImage.initrd" Linux image when you just
2326 change a file in your "initrd"). Also, a field-upgrade of the
2327 software is easier now.
2333 Porting Linux to U-Boot based systems:
2334 ---------------------------------------
2336 U-Boot cannot save you from doing all the necessary modifications to
2337 configure the Linux device drivers for use with your target hardware
2338 (no, we don't intend to provide a full virtual machine interface to
2341 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2343 Just make sure your machine specific header file (for instance
2344 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2345 Information structure as we define in include/u-boot.h, and make
2346 sure that your definition of IMAP_ADDR uses the same value as your
2347 U-Boot configuration in CFG_IMMR.
2350 Configuring the Linux kernel:
2351 -----------------------------
2353 No specific requirements for U-Boot. Make sure you have some root
2354 device (initial ramdisk, NFS) for your target system.
2357 Building a Linux Image:
2358 -----------------------
2360 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2361 not used. If you use recent kernel source, a new build target
2362 "uImage" will exist which automatically builds an image usable by
2363 U-Boot. Most older kernels also have support for a "pImage" target,
2364 which was introduced for our predecessor project PPCBoot and uses a
2365 100% compatible format.
2374 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2375 encapsulate a compressed Linux kernel image with header information,
2376 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2378 * build a standard "vmlinux" kernel image (in ELF binary format):
2380 * convert the kernel into a raw binary image:
2382 ${CROSS_COMPILE}-objcopy -O binary \
2383 -R .note -R .comment \
2384 -S vmlinux linux.bin
2386 * compress the binary image:
2390 * package compressed binary image for U-Boot:
2392 mkimage -A ppc -O linux -T kernel -C gzip \
2393 -a 0 -e 0 -n "Linux Kernel Image" \
2394 -d linux.bin.gz uImage
2397 The "mkimage" tool can also be used to create ramdisk images for use
2398 with U-Boot, either separated from the Linux kernel image, or
2399 combined into one file. "mkimage" encapsulates the images with a 64
2400 byte header containing information about target architecture,
2401 operating system, image type, compression method, entry points, time
2402 stamp, CRC32 checksums, etc.
2404 "mkimage" can be called in two ways: to verify existing images and
2405 print the header information, or to build new images.
2407 In the first form (with "-l" option) mkimage lists the information
2408 contained in the header of an existing U-Boot image; this includes
2409 checksum verification:
2411 tools/mkimage -l image
2412 -l ==> list image header information
2414 The second form (with "-d" option) is used to build a U-Boot image
2415 from a "data file" which is used as image payload:
2417 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2418 -n name -d data_file image
2419 -A ==> set architecture to 'arch'
2420 -O ==> set operating system to 'os'
2421 -T ==> set image type to 'type'
2422 -C ==> set compression type 'comp'
2423 -a ==> set load address to 'addr' (hex)
2424 -e ==> set entry point to 'ep' (hex)
2425 -n ==> set image name to 'name'
2426 -d ==> use image data from 'datafile'
2428 Right now, all Linux kernels use the same load address (0x00000000),
2429 but the entry point address depends on the kernel version:
2431 - 2.2.x kernels have the entry point at 0x0000000C,
2432 - 2.3.x and later kernels have the entry point at 0x00000000.
2434 So a typical call to build a U-Boot image would read:
2436 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2437 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2438 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2439 > examples/uImage.TQM850L
2440 Image Name: 2.4.4 kernel for TQM850L
2441 Created: Wed Jul 19 02:34:59 2000
2442 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2443 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2444 Load Address: 0x00000000
2445 Entry Point: 0x00000000
2447 To verify the contents of the image (or check for corruption):
2449 -> tools/mkimage -l 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 NOTE: for embedded systems where boot time is critical you can trade
2458 speed for memory and install an UNCOMPRESSED image instead: this
2459 needs more space in Flash, but boots much faster since it does not
2460 need to be uncompressed:
2462 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2463 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2464 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2465 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2466 > examples/uImage.TQM850L-uncompressed
2467 Image Name: 2.4.4 kernel for TQM850L
2468 Created: Wed Jul 19 02:34:59 2000
2469 Image Type: PowerPC Linux Kernel Image (uncompressed)
2470 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2471 Load Address: 0x00000000
2472 Entry Point: 0x00000000
2475 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2476 when your kernel is intended to use an initial ramdisk:
2478 -> tools/mkimage -n 'Simple Ramdisk Image' \
2479 > -A ppc -O linux -T ramdisk -C gzip \
2480 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
2481 Image Name: Simple Ramdisk Image
2482 Created: Wed Jan 12 14:01:50 2000
2483 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2484 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
2485 Load Address: 0x00000000
2486 Entry Point: 0x00000000
2489 Installing a Linux Image:
2490 -------------------------
2492 To downloading a U-Boot image over the serial (console) interface,
2493 you must convert the image to S-Record format:
2495 objcopy -I binary -O srec examples/image examples/image.srec
2497 The 'objcopy' does not understand the information in the U-Boot
2498 image header, so the resulting S-Record file will be relative to
2499 address 0x00000000. To load it to a given address, you need to
2500 specify the target address as 'offset' parameter with the 'loads'
2503 Example: install the image to address 0x40100000 (which on the
2504 TQM8xxL is in the first Flash bank):
2506 => erase 40100000 401FFFFF
2512 ## Ready for S-Record download ...
2513 ~>examples/image.srec
2514 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
2516 15989 15990 15991 15992
2517 [file transfer complete]
2519 ## Start Addr = 0x00000000
2522 You can check the success of the download using the 'iminfo' command;
2523 this includes a checksum verification so you can be sure no data
2524 corruption happened:
2528 ## Checking Image at 40100000 ...
2529 Image Name: 2.2.13 for initrd on TQM850L
2530 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2531 Data Size: 335725 Bytes = 327 kB = 0 MB
2532 Load Address: 00000000
2533 Entry Point: 0000000c
2534 Verifying Checksum ... OK
2540 The "bootm" command is used to boot an application that is stored in
2541 memory (RAM or Flash). In case of a Linux kernel image, the contents
2542 of the "bootargs" environment variable is passed to the kernel as
2543 parameters. You can check and modify this variable using the
2544 "printenv" and "setenv" commands:
2547 => printenv bootargs
2548 bootargs=root=/dev/ram
2550 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2552 => printenv bootargs
2553 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2556 ## Booting Linux kernel at 40020000 ...
2557 Image Name: 2.2.13 for NFS on TQM850L
2558 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2559 Data Size: 381681 Bytes = 372 kB = 0 MB
2560 Load Address: 00000000
2561 Entry Point: 0000000c
2562 Verifying Checksum ... OK
2563 Uncompressing Kernel Image ... OK
2564 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
2565 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
2566 time_init: decrementer frequency = 187500000/60
2567 Calibrating delay loop... 49.77 BogoMIPS
2568 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
2571 If you want to boot a Linux kernel with initial ram disk, you pass
2572 the memory addresses of both the kernel and the initrd image (PPBCOOT
2573 format!) to the "bootm" command:
2575 => imi 40100000 40200000
2577 ## Checking Image at 40100000 ...
2578 Image Name: 2.2.13 for initrd on TQM850L
2579 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2580 Data Size: 335725 Bytes = 327 kB = 0 MB
2581 Load Address: 00000000
2582 Entry Point: 0000000c
2583 Verifying Checksum ... OK
2585 ## Checking Image at 40200000 ...
2586 Image Name: Simple Ramdisk Image
2587 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2588 Data Size: 566530 Bytes = 553 kB = 0 MB
2589 Load Address: 00000000
2590 Entry Point: 00000000
2591 Verifying Checksum ... OK
2593 => bootm 40100000 40200000
2594 ## Booting Linux kernel at 40100000 ...
2595 Image Name: 2.2.13 for initrd on TQM850L
2596 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2597 Data Size: 335725 Bytes = 327 kB = 0 MB
2598 Load Address: 00000000
2599 Entry Point: 0000000c
2600 Verifying Checksum ... OK
2601 Uncompressing Kernel Image ... OK
2602 ## Loading RAMDisk Image at 40200000 ...
2603 Image Name: Simple Ramdisk Image
2604 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
2605 Data Size: 566530 Bytes = 553 kB = 0 MB
2606 Load Address: 00000000
2607 Entry Point: 00000000
2608 Verifying Checksum ... OK
2609 Loading Ramdisk ... OK
2610 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
2611 Boot arguments: root=/dev/ram
2612 time_init: decrementer frequency = 187500000/60
2613 Calibrating delay loop... 49.77 BogoMIPS
2615 RAMDISK: Compressed image found at block 0
2616 VFS: Mounted root (ext2 filesystem).
2620 More About U-Boot Image Types:
2621 ------------------------------
2623 U-Boot supports the following image types:
2625 "Standalone Programs" are directly runnable in the environment
2626 provided by U-Boot; it is expected that (if they behave
2627 well) you can continue to work in U-Boot after return from
2628 the Standalone Program.
2629 "OS Kernel Images" are usually images of some Embedded OS which
2630 will take over control completely. Usually these programs
2631 will install their own set of exception handlers, device
2632 drivers, set up the MMU, etc. - this means, that you cannot
2633 expect to re-enter U-Boot except by resetting the CPU.
2634 "RAMDisk Images" are more or less just data blocks, and their
2635 parameters (address, size) are passed to an OS kernel that is
2637 "Multi-File Images" contain several images, typically an OS
2638 (Linux) kernel image and one or more data images like
2639 RAMDisks. This construct is useful for instance when you want
2640 to boot over the network using BOOTP etc., where the boot
2641 server provides just a single image file, but you want to get
2642 for instance an OS kernel and a RAMDisk image.
2644 "Multi-File Images" start with a list of image sizes, each
2645 image size (in bytes) specified by an "uint32_t" in network
2646 byte order. This list is terminated by an "(uint32_t)0".
2647 Immediately after the terminating 0 follow the images, one by
2648 one, all aligned on "uint32_t" boundaries (size rounded up to
2649 a multiple of 4 bytes).
2651 "Firmware Images" are binary images containing firmware (like
2652 U-Boot or FPGA images) which usually will be programmed to
2655 "Script files" are command sequences that will be executed by
2656 U-Boot's command interpreter; this feature is especially
2657 useful when you configure U-Boot to use a real shell (hush)
2658 as command interpreter.
2664 One of the features of U-Boot is that you can dynamically load and
2665 run "standalone" applications, which can use some resources of
2666 U-Boot like console I/O functions or interrupt services.
2668 Two simple examples are included with the sources:
2673 'examples/hello_world.c' contains a small "Hello World" Demo
2674 application; it is automatically compiled when you build U-Boot.
2675 It's configured to run at address 0x00040004, so you can play with it
2679 ## Ready for S-Record download ...
2680 ~>examples/hello_world.srec
2681 1 2 3 4 5 6 7 8 9 10 11 ...
2682 [file transfer complete]
2684 ## Start Addr = 0x00040004
2686 => go 40004 Hello World! This is a test.
2687 ## Starting application at 0x00040004 ...
2698 Hit any key to exit ...
2700 ## Application terminated, rc = 0x0
2702 Another example, which demonstrates how to register a CPM interrupt
2703 handler with the U-Boot code, can be found in 'examples/timer.c'.
2704 Here, a CPM timer is set up to generate an interrupt every second.
2705 The interrupt service routine is trivial, just printing a '.'
2706 character, but this is just a demo program. The application can be
2707 controlled by the following keys:
2709 ? - print current values og the CPM Timer registers
2710 b - enable interrupts and start timer
2711 e - stop timer and disable interrupts
2712 q - quit application
2715 ## Ready for S-Record download ...
2716 ~>examples/timer.srec
2717 1 2 3 4 5 6 7 8 9 10 11 ...
2718 [file transfer complete]
2720 ## Start Addr = 0x00040004
2723 ## Starting application at 0x00040004 ...
2726 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
2729 [q, b, e, ?] Set interval 1000000 us
2732 [q, b, e, ?] ........
2733 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
2736 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
2739 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
2742 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
2744 [q, b, e, ?] ...Stopping timer
2746 [q, b, e, ?] ## Application terminated, rc = 0x0
2752 Over time, many people have reported problems when trying to use the
2753 "minicom" terminal emulation program for serial download. I (wd)
2754 consider minicom to be broken, and recommend not to use it. Under
2755 Unix, I recommend to use C-Kermit for general purpose use (and
2756 especially for kermit binary protocol download ("loadb" command), and
2757 use "cu" for S-Record download ("loads" command).
2759 Nevertheless, if you absolutely want to use it try adding this
2760 configuration to your "File transfer protocols" section:
2762 Name Program Name U/D FullScr IO-Red. Multi
2763 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
2764 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
2770 Starting at version 0.9.2, U-Boot supports NetBSD both as host
2771 (build U-Boot) and target system (boots NetBSD/mpc8xx).
2773 Building requires a cross environment; it is known to work on
2774 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
2775 need gmake since the Makefiles are not compatible with BSD make).
2776 Note that the cross-powerpc package does not install include files;
2777 attempting to build U-Boot will fail because <machine/ansi.h> is
2778 missing. This file has to be installed and patched manually:
2780 # cd /usr/pkg/cross/powerpc-netbsd/include
2782 # ln -s powerpc machine
2783 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
2784 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
2786 Native builds *don't* work due to incompatibilities between native
2787 and U-Boot include files.
2789 Booting assumes that (the first part of) the image booted is a
2790 stage-2 loader which in turn loads and then invokes the kernel
2791 proper. Loader sources will eventually appear in the NetBSD source
2792 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
2793 meantime, send mail to bruno@exet-ag.de and/or wd@denx.de for
2797 Implementation Internals:
2798 =========================
2800 The following is not intended to be a complete description of every
2801 implementation detail. However, it should help to understand the
2802 inner workings of U-Boot and make it easier to port it to custom
2806 Initial Stack, Global Data:
2807 ---------------------------
2809 The implementation of U-Boot is complicated by the fact that U-Boot
2810 starts running out of ROM (flash memory), usually without access to
2811 system RAM (because the memory controller is not initialized yet).
2812 This means that we don't have writable Data or BSS segments, and BSS
2813 is not initialized as zero. To be able to get a C environment working
2814 at all, we have to allocate at least a minimal stack. Implementation
2815 options for this are defined and restricted by the CPU used: Some CPU
2816 models provide on-chip memory (like the IMMR area on MPC8xx and
2817 MPC826x processors), on others (parts of) the data cache can be
2818 locked as (mis-) used as memory, etc.
2820 Chris Hallinan posted a good summary of these issues to the
2821 u-boot-users mailing list:
2823 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
2824 From: "Chris Hallinan" <clh@net1plus.com>
2825 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
2828 Correct me if I'm wrong, folks, but the way I understand it
2829 is this: Using DCACHE as initial RAM for Stack, etc, does not
2830 require any physical RAM backing up the cache. The cleverness
2831 is that the cache is being used as a temporary supply of
2832 necessary storage before the SDRAM controller is setup. It's
2833 beyond the scope of this list to expain the details, but you
2834 can see how this works by studying the cache architecture and
2835 operation in the architecture and processor-specific manuals.
2837 OCM is On Chip Memory, which I believe the 405GP has 4K. It
2838 is another option for the system designer to use as an
2839 initial stack/ram area prior to SDRAM being available. Either
2840 option should work for you. Using CS 4 should be fine if your
2841 board designers haven't used it for something that would
2842 cause you grief during the initial boot! It is frequently not
2845 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
2846 with your processor/board/system design. The default value
2847 you will find in any recent u-boot distribution in
2848 Walnut405.h should work for you. I'd set it to a value larger
2849 than your SDRAM module. If you have a 64MB SDRAM module, set
2850 it above 400_0000. Just make sure your board has no resources
2851 that are supposed to respond to that address! That code in
2852 start.S has been around a while and should work as is when
2853 you get the config right.
2858 It is essential to remember this, since it has some impact on the C
2859 code for the initialization procedures:
2861 * Initialized global data (data segment) is read-only. Do not attempt
2864 * Do not use any unitialized global data (or implicitely initialized
2865 as zero data - BSS segment) at all - this is undefined, initiali-
2866 zation is performed later (when relocating to RAM).
2868 * Stack space is very limited. Avoid big data buffers or things like
2871 Having only the stack as writable memory limits means we cannot use
2872 normal global data to share information beween the code. But it
2873 turned out that the implementation of U-Boot can be greatly
2874 simplified by making a global data structure (gd_t) available to all
2875 functions. We could pass a pointer to this data as argument to _all_
2876 functions, but this would bloat the code. Instead we use a feature of
2877 the GCC compiler (Global Register Variables) to share the data: we
2878 place a pointer (gd) to the global data into a register which we
2879 reserve for this purpose.
2881 When choosing a register for such a purpose we are restricted by the
2882 relevant (E)ABI specifications for the current architecture, and by
2883 GCC's implementation.
2885 For PowerPC, the following registers have specific use:
2888 R3-R4: parameter passing and return values
2889 R5-R10: parameter passing
2890 R13: small data area pointer
2894 (U-Boot also uses R14 as internal GOT pointer.)
2896 ==> U-Boot will use R29 to hold a pointer to the global data
2898 Note: on PPC, we could use a static initializer (since the
2899 address of the global data structure is known at compile time),
2900 but it turned out that reserving a register results in somewhat
2901 smaller code - although the code savings are not that big (on
2902 average for all boards 752 bytes for the whole U-Boot image,
2903 624 text + 127 data).
2905 On ARM, the following registers are used:
2907 R0: function argument word/integer result
2908 R1-R3: function argument word
2910 R10: stack limit (used only if stack checking if enabled)
2911 R11: argument (frame) pointer
2912 R12: temporary workspace
2915 R15: program counter
2917 ==> U-Boot will use R8 to hold a pointer to the global data
2923 U-Boot runs in system state and uses physical addresses, i.e. the
2924 MMU is not used either for address mapping nor for memory protection.
2926 The available memory is mapped to fixed addresses using the memory
2927 controller. In this process, a contiguous block is formed for each
2928 memory type (Flash, SDRAM, SRAM), even when it consists of several
2929 physical memory banks.
2931 U-Boot is installed in the first 128 kB of the first Flash bank (on
2932 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
2933 booting and sizing and initializing DRAM, the code relocates itself
2934 to the upper end of DRAM. Immediately below the U-Boot code some
2935 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
2936 configuration setting]. Below that, a structure with global Board
2937 Info data is placed, followed by the stack (growing downward).
2939 Additionally, some exception handler code is copied to the low 8 kB
2940 of DRAM (0x00000000 ... 0x00001FFF).
2942 So a typical memory configuration with 16 MB of DRAM could look like
2945 0x0000 0000 Exception Vector code
2948 0x0000 2000 Free for Application Use
2954 0x00FB FF20 Monitor Stack (Growing downward)
2955 0x00FB FFAC Board Info Data and permanent copy of global data
2956 0x00FC 0000 Malloc Arena
2959 0x00FE 0000 RAM Copy of Monitor Code
2960 ... eventually: LCD or video framebuffer
2961 ... eventually: pRAM (Protected RAM - unchanged by reset)
2962 0x00FF FFFF [End of RAM]
2965 System Initialization:
2966 ----------------------
2968 In the reset configuration, U-Boot starts at the reset entry point
2969 (on most PowerPC systens at address 0x00000100). Because of the reset
2970 configuration for CS0# this is a mirror of the onboard Flash memory.
2971 To be able to re-map memory U-Boot then jumps to its link address.
2972 To be able to implement the initialization code in C, a (small!)
2973 initial stack is set up in the internal Dual Ported RAM (in case CPUs
2974 which provide such a feature like MPC8xx or MPC8260), or in a locked
2975 part of the data cache. After that, U-Boot initializes the CPU core,
2976 the caches and the SIU.
2978 Next, all (potentially) available memory banks are mapped using a
2979 preliminary mapping. For example, we put them on 512 MB boundaries
2980 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
2981 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
2982 programmed for SDRAM access. Using the temporary configuration, a
2983 simple memory test is run that determines the size of the SDRAM
2986 When there is more than one SDRAM bank, and the banks are of
2987 different size, the largest is mapped first. For equal size, the first
2988 bank (CS2#) is mapped first. The first mapping is always for address
2989 0x00000000, with any additional banks following immediately to create
2990 contiguous memory starting from 0.
2992 Then, the monitor installs itself at the upper end of the SDRAM area
2993 and allocates memory for use by malloc() and for the global Board
2994 Info data; also, the exception vector code is copied to the low RAM
2995 pages, and the final stack is set up.
2997 Only after this relocation will you have a "normal" C environment;
2998 until that you are restricted in several ways, mostly because you are
2999 running from ROM, and because the code will have to be relocated to a
3003 U-Boot Porting Guide:
3004 ----------------------
3006 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3010 int main (int argc, char *argv[])
3012 sighandler_t no_more_time;
3014 signal (SIGALRM, no_more_time);
3015 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3017 if (available_money > available_manpower) {
3018 pay consultant to port U-Boot;
3022 Download latest U-Boot source;
3024 Subscribe to u-boot-users mailing list;
3027 email ("Hi, I am new to U-Boot, how do I get started?");
3031 Read the README file in the top level directory;
3032 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3033 Read the source, Luke;
3036 if (available_money > toLocalCurrency ($2500)) {
3039 Add a lot of aggravation and time;
3042 Create your own board support subdirectory;
3044 Create your own board config file;
3048 Add / modify source code;
3052 email ("Hi, I am having problems...");
3054 Send patch file to Wolfgang;
3059 void no_more_time (int sig)
3068 All contributions to U-Boot should conform to the Linux kernel
3069 coding style; see the file "Documentation/CodingStyle" in your Linux
3070 kernel source directory.
3072 Please note that U-Boot is implemented in C (and to some small parts
3073 in Assembler); no C++ is used, so please do not use C++ style
3074 comments (//) in your code.
3076 Please also stick to the following formatting rules:
3077 - remove any trailing white space
3078 - use TAB characters for indentation, not spaces
3079 - make sure NOT to use DOS '\r\n' line feeds
3080 - do not add more than 2 empty lines to source files
3081 - do not add trailing empty lines to source files
3083 Submissions which do not conform to the standards may be returned
3084 with a request to reformat the changes.
3090 Since the number of patches for U-Boot is growing, we need to
3091 establish some rules. Submissions which do not conform to these rules
3092 may be rejected, even when they contain important and valuable stuff.
3095 When you send a patch, please include the following information with
3098 * For bug fixes: a description of the bug and how your patch fixes
3099 this bug. Please try to include a way of demonstrating that the
3100 patch actually fixes something.
3102 * For new features: a description of the feature and your
3105 * A CHANGELOG entry as plaintext (separate from the patch)
3107 * For major contributions, your entry to the CREDITS file
3109 * When you add support for a new board, don't forget to add this
3110 board to the MAKEALL script, too.
3112 * If your patch adds new configuration options, don't forget to
3113 document these in the README file.
3115 * The patch itself. If you are accessing the CVS repository use "cvs
3116 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3117 version of diff does not support these options, then get the latest
3118 version of GNU diff.
3120 The current directory when running this command shall be the top
3121 level directory of the U-Boot source tree, or it's parent directory
3122 (i. e. please make sure that your patch includes sufficient
3123 directory information for the affected files).
3125 We accept patches as plain text, MIME attachments or as uuencoded
3128 * If one logical set of modifications affects or creates several
3129 files, all these changes shall be submitted in a SINGLE patch file.
3131 * Changesets that contain different, unrelated modifications shall be
3132 submitted as SEPARATE patches, one patch per changeset.
3137 * Before sending the patch, run the MAKEALL script on your patched
3138 source tree and make sure that no errors or warnings are reported
3139 for any of the boards.
3141 * Keep your modifications to the necessary minimum: A patch
3142 containing several unrelated changes or arbitrary reformats will be
3143 returned with a request to re-formatting / split it.
3145 * If you modify existing code, make sure that your new code does not
3146 add to the memory footprint of the code ;-) Small is beautiful!
3147 When adding new features, these should compile conditionally only
3148 (using #ifdef), and the resulting code with the new feature
3149 disabled must not need more memory than the old code without your
projects / platform / kernel / u-boot.git / blob