2 # (C) Copyright 2000 - 2005
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port.
60 In case you have questions about, problems with or contributions for
61 U-Boot you should send a message to the U-Boot mailing list at
62 <u-boot-users@lists.sourceforge.net>. There is also an archive of
63 previous traffic on the mailing list - please search the archive
64 before asking FAQ's. Please see
65 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
71 - start from 8xxrom sources
72 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
74 - make it easier to add custom boards
75 - make it possible to add other [PowerPC] CPUs
76 - extend functions, especially:
77 * Provide extended interface to Linux boot loader
80 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
81 - create ARMBoot project (http://sourceforge.net/projects/armboot)
82 - add other CPU families (starting with ARM)
83 - create U-Boot project (http://sourceforge.net/projects/u-boot)
89 The "official" name of this project is "Das U-Boot". The spelling
90 "U-Boot" shall be used in all written text (documentation, comments
91 in source files etc.). Example:
93 This is the README file for the U-Boot project.
95 File names etc. shall be based on the string "u-boot". Examples:
97 include/asm-ppc/u-boot.h
99 #include <asm/u-boot.h>
101 Variable names, preprocessor constants etc. shall be either based on
102 the string "u_boot" or on "U_BOOT". Example:
104 U_BOOT_VERSION u_boot_logo
105 IH_OS_U_BOOT u_boot_hush_start
111 U-Boot uses a 3 level version number containing a version, a
112 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
113 sub-version "34", and patchlevel "4".
115 The patchlevel is used to indicate certain stages of development
116 between released versions, i. e. officially released versions of
117 U-Boot will always have a patchlevel of "0".
123 - board Board dependent files
124 - common Misc architecture independent functions
125 - cpu CPU specific files
126 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
127 - arm720t Files specific to ARM 720 CPUs
128 - arm920t Files specific to ARM 920 CPUs
129 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
130 - imx Files specific to Freescale MC9328 i.MX CPUs
131 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
132 - arm925t Files specific to ARM 925 CPUs
133 - arm926ejs Files specific to ARM 926 CPUs
134 - arm1136 Files specific to ARM 1136 CPUs
135 - at32ap Files specific to Atmel AVR32 AP CPUs
136 - i386 Files specific to i386 CPUs
137 - ixp Files specific to Intel XScale IXP CPUs
138 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
139 - mips Files specific to MIPS CPUs
140 - mpc5xx Files specific to Freescale MPC5xx CPUs
141 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
142 - mpc8xx Files specific to Freescale MPC8xx CPUs
143 - mpc8220 Files specific to Freescale MPC8220 CPUs
144 - mpc824x Files specific to Freescale MPC824x CPUs
145 - mpc8260 Files specific to Freescale MPC8260 CPUs
146 - mpc85xx Files specific to Freescale MPC85xx CPUs
147 - nios Files specific to Altera NIOS CPUs
148 - nios2 Files specific to Altera Nios-II CPUs
149 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
150 - pxa Files specific to Intel XScale PXA CPUs
151 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
152 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
153 - disk Code for disk drive partition handling
154 - doc Documentation (don't expect too much)
155 - drivers Commonly used device drivers
156 - dtt Digital Thermometer and Thermostat drivers
157 - examples Example code for standalone applications, etc.
158 - include Header Files
159 - lib_arm Files generic to ARM architecture
160 - lib_avr32 Files generic to AVR32 architecture
161 - lib_generic Files generic to all architectures
162 - lib_i386 Files generic to i386 architecture
163 - lib_m68k Files generic to m68k architecture
164 - lib_mips Files generic to MIPS architecture
165 - lib_nios Files generic to NIOS architecture
166 - lib_ppc Files generic to PowerPC architecture
167 - net Networking code
168 - post Power On Self Test
169 - rtc Real Time Clock drivers
170 - tools Tools to build S-Record or U-Boot images, etc.
172 Software Configuration:
173 =======================
175 Configuration is usually done using C preprocessor defines; the
176 rationale behind that is to avoid dead code whenever possible.
178 There are two classes of configuration variables:
180 * Configuration _OPTIONS_:
181 These are selectable by the user and have names beginning with
184 * Configuration _SETTINGS_:
185 These depend on the hardware etc. and should not be meddled with if
186 you don't know what you're doing; they have names beginning with
189 Later we will add a configuration tool - probably similar to or even
190 identical to what's used for the Linux kernel. Right now, we have to
191 do the configuration by hand, which means creating some symbolic
192 links and editing some configuration files. We use the TQM8xxL boards
196 Selection of Processor Architecture and Board Type:
197 ---------------------------------------------------
199 For all supported boards there are ready-to-use default
200 configurations available; just type "make <board_name>_config".
202 Example: For a TQM823L module type:
207 For the Cogent platform, you need to specify the cpu type as well;
208 e.g. "make cogent_mpc8xx_config". And also configure the cogent
209 directory according to the instructions in cogent/README.
212 Configuration Options:
213 ----------------------
215 Configuration depends on the combination of board and CPU type; all
216 such information is kept in a configuration file
217 "include/configs/<board_name>.h".
219 Example: For a TQM823L module, all configuration settings are in
220 "include/configs/TQM823L.h".
223 Many of the options are named exactly as the corresponding Linux
224 kernel configuration options. The intention is to make it easier to
225 build a config tool - later.
228 The following options need to be configured:
230 - CPU Type: Define exactly one of
234 CONFIG_MPC823, CONFIG_MPC850, CONFIG_MPC855, CONFIG_MPC860
237 or CONFIG_MPC824X, CONFIG_MPC8260
253 MicroBlaze based CPUs:
254 ----------------------
258 ----------------------
262 ----------------------
265 - Board Type: Define exactly one of
267 PowerPC based boards:
268 ---------------------
270 CONFIG_ADCIOP CONFIG_FPS860L CONFIG_OXC
271 CONFIG_ADS860 CONFIG_GEN860T CONFIG_PCI405
272 CONFIG_AMX860 CONFIG_GENIETV CONFIG_PCIPPC2
273 CONFIG_AP1000 CONFIG_GTH CONFIG_PCIPPC6
274 CONFIG_AR405 CONFIG_gw8260 CONFIG_pcu_e
275 CONFIG_BAB7xx CONFIG_hermes CONFIG_PIP405
276 CONFIG_BC3450 CONFIG_hymod CONFIG_PM826
277 CONFIG_c2mon CONFIG_IAD210 CONFIG_ppmc8260
278 CONFIG_CANBT CONFIG_ICU862 CONFIG_QS823
279 CONFIG_CCM CONFIG_IP860 CONFIG_QS850
280 CONFIG_CMI CONFIG_IPHASE4539 CONFIG_QS860T
281 CONFIG_cogent_mpc8260 CONFIG_IVML24 CONFIG_RBC823
282 CONFIG_cogent_mpc8xx CONFIG_IVML24_128 CONFIG_RPXClassic
283 CONFIG_CPCI405 CONFIG_IVML24_256 CONFIG_RPXlite
284 CONFIG_CPCI4052 CONFIG_IVMS8 CONFIG_RPXsuper
285 CONFIG_CPCIISER4 CONFIG_IVMS8_128 CONFIG_rsdproto
286 CONFIG_CPU86 CONFIG_IVMS8_256 CONFIG_sacsng
287 CONFIG_CRAYL1 CONFIG_JSE CONFIG_Sandpoint8240
288 CONFIG_CSB272 CONFIG_LANTEC CONFIG_Sandpoint8245
289 CONFIG_CU824 CONFIG_LITE5200B CONFIG_sbc8260
290 CONFIG_DASA_SIM CONFIG_lwmon CONFIG_sbc8560
291 CONFIG_DB64360 CONFIG_MBX CONFIG_SM850
292 CONFIG_DB64460 CONFIG_MBX860T CONFIG_SPD823TS
293 CONFIG_DU405 CONFIG_MHPC CONFIG_STXGP3
294 CONFIG_DUET_ADS CONFIG_MIP405 CONFIG_SXNI855T
295 CONFIG_EBONY CONFIG_MOUSSE CONFIG_TQM823L
296 CONFIG_ELPPC CONFIG_MPC8260ADS CONFIG_TQM8260
297 CONFIG_ELPT860 CONFIG_MPC8540ADS CONFIG_TQM850L
298 CONFIG_ep8260 CONFIG_MPC8540EVAL CONFIG_TQM855L
299 CONFIG_ERIC CONFIG_MPC8560ADS CONFIG_TQM860L
300 CONFIG_ESTEEM192E CONFIG_MUSENKI CONFIG_TTTech
301 CONFIG_ETX094 CONFIG_MVS1 CONFIG_UTX8245
302 CONFIG_EVB64260 CONFIG_NETPHONE CONFIG_V37
303 CONFIG_FADS823 CONFIG_NETTA CONFIG_W7OLMC
304 CONFIG_FADS850SAR CONFIG_NETVIA CONFIG_W7OLMG
305 CONFIG_FADS860T CONFIG_NX823 CONFIG_WALNUT
306 CONFIG_FLAGADM CONFIG_OCRTC CONFIG_ZPC1900
307 CONFIG_FPS850L CONFIG_ORSG CONFIG_ZUMA
312 CONFIG_ARMADILLO, CONFIG_AT91RM9200DK, CONFIG_CERF250,
313 CONFIG_CSB637, CONFIG_DELTA, CONFIG_DNP1110,
314 CONFIG_EP7312, CONFIG_H2_OMAP1610, CONFIG_HHP_CRADLE,
315 CONFIG_IMPA7, CONFIG_INNOVATOROMAP1510, CONFIG_INNOVATOROMAP1610,
316 CONFIG_KB9202, CONFIG_LART, CONFIG_LPD7A400,
317 CONFIG_LUBBOCK, CONFIG_OSK_OMAP5912, CONFIG_OMAP2420H4,
318 CONFIG_PLEB2, CONFIG_SHANNON, CONFIG_P2_OMAP730,
319 CONFIG_SMDK2400, CONFIG_SMDK2410, CONFIG_TRAB,
322 MicroBlaze based boards:
323 ------------------------
328 ------------------------
330 CONFIG_PCI5441 CONFIG_PK1C20
331 CONFIG_EP1C20 CONFIG_EP1S10 CONFIG_EP1S40
338 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
339 Define exactly one of
343 - CPU Module Type: (if CONFIG_COGENT is defined)
344 Define exactly one of
346 --- FIXME --- not tested yet:
347 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
348 CONFIG_CMA287_23, CONFIG_CMA287_50
350 - Motherboard Type: (if CONFIG_COGENT is defined)
351 Define exactly one of
352 CONFIG_CMA101, CONFIG_CMA102
354 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
355 Define one or more of
358 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
359 Define one or more of
360 CONFIG_LCD_HEARTBEAT - update a character position on
361 the lcd display every second with
364 - Board flavour: (if CONFIG_MPC8260ADS is defined)
367 CFG_8260ADS - original MPC8260ADS
368 CFG_8266ADS - MPC8266ADS
369 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
370 CFG_8272ADS - MPC8272ADS
372 - MPC824X Family Member (if CONFIG_MPC824X is defined)
373 Define exactly one of
374 CONFIG_MPC8240, CONFIG_MPC8245
376 - 8xx CPU Options: (if using an MPC8xx cpu)
377 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
378 get_gclk_freq() cannot work
379 e.g. if there is no 32KHz
380 reference PIT/RTC clock
381 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
384 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
387 CONFIG_8xx_CPUCLK_DEFAULT
388 See doc/README.MPC866
392 Define this to measure the actual CPU clock instead
393 of relying on the correctness of the configured
394 values. Mostly useful for board bringup to make sure
395 the PLL is locked at the intended frequency. Note
396 that this requires a (stable) reference clock (32 kHz
397 RTC clock or CFG_8XX_XIN)
399 - Intel Monahans options:
400 CFG_MONAHANS_RUN_MODE_OSC_RATIO
402 Defines the Monahans run mode to oscillator
403 ratio. Valid values are 8, 16, 24, 31. The core
404 frequency is this value multiplied by 13 MHz.
406 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
408 Defines the Monahans turbo mode to oscillator
409 ratio. Valid values are 1 (default if undefined) and
410 2. The core frequency as calculated above is multiplied
413 - Linux Kernel Interface:
416 U-Boot stores all clock information in Hz
417 internally. For binary compatibility with older Linux
418 kernels (which expect the clocks passed in the
419 bd_info data to be in MHz) the environment variable
420 "clocks_in_mhz" can be defined so that U-Boot
421 converts clock data to MHZ before passing it to the
423 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
424 "clocks_in_mhz=1" is automatically included in the
427 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
429 When transfering memsize parameter to linux, some versions
430 expect it to be in bytes, others in MB.
431 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
435 New kernel versions are expecting firmware settings to be
436 passed using flat open firmware trees.
437 The environment variable "disable_of", when set, disables this
440 CONFIG_OF_FLAT_TREE_MAX_SIZE
442 The maximum size of the constructed OF tree.
444 OF_CPU - The proper name of the cpus node.
445 OF_SOC - The proper name of the soc node.
446 OF_TBCLK - The timebase frequency.
447 OF_STDOUT_PATH - The path to the console device
451 The resulting flat device tree will have a copy of the bd_t.
452 Space should be pre-allocated in the dts for the bd_t.
454 CONFIG_OF_HAS_UBOOT_ENV
456 The resulting flat device tree will have a copy of u-boot's
457 environment variables
459 CONFIG_OF_BOARD_SETUP
461 Board code has addition modification that it wants to make
462 to the flat device tree before handing it off to the kernel
466 This define fills in the correct boot cpu in the boot
467 param header, the default value is zero if undefined.
472 Define this if you want support for Amba PrimeCell PL010 UARTs.
476 Define this if you want support for Amba PrimeCell PL011 UARTs.
480 If you have Amba PrimeCell PL011 UARTs, set this variable to
481 the clock speed of the UARTs.
485 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
486 define this to a list of base addresses for each (supported)
487 port. See e.g. include/configs/versatile.h
491 Depending on board, define exactly one serial port
492 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
493 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
494 console by defining CONFIG_8xx_CONS_NONE
496 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
497 port routines must be defined elsewhere
498 (i.e. serial_init(), serial_getc(), ...)
501 Enables console device for a color framebuffer. Needs following
502 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
503 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
505 VIDEO_HW_RECTFILL graphic chip supports
508 VIDEO_HW_BITBLT graphic chip supports
509 bit-blit (cf. smiLynxEM)
510 VIDEO_VISIBLE_COLS visible pixel columns
512 VIDEO_VISIBLE_ROWS visible pixel rows
513 VIDEO_PIXEL_SIZE bytes per pixel
514 VIDEO_DATA_FORMAT graphic data format
515 (0-5, cf. cfb_console.c)
516 VIDEO_FB_ADRS framebuffer address
517 VIDEO_KBD_INIT_FCT keyboard int fct
518 (i.e. i8042_kbd_init())
519 VIDEO_TSTC_FCT test char fct
521 VIDEO_GETC_FCT get char fct
523 CONFIG_CONSOLE_CURSOR cursor drawing on/off
524 (requires blink timer
526 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
527 CONFIG_CONSOLE_TIME display time/date info in
529 (requires CFG_CMD_DATE)
530 CONFIG_VIDEO_LOGO display Linux logo in
532 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
533 linux_logo.h for logo.
534 Requires CONFIG_VIDEO_LOGO
535 CONFIG_CONSOLE_EXTRA_INFO
536 addional board info beside
539 When CONFIG_CFB_CONSOLE is defined, video console is
540 default i/o. Serial console can be forced with
541 environment 'console=serial'.
543 When CONFIG_SILENT_CONSOLE is defined, all console
544 messages (by U-Boot and Linux!) can be silenced with
545 the "silent" environment variable. See
546 doc/README.silent for more information.
549 CONFIG_BAUDRATE - in bps
550 Select one of the baudrates listed in
551 CFG_BAUDRATE_TABLE, see below.
552 CFG_BRGCLK_PRESCALE, baudrate prescale
554 - Interrupt driven serial port input:
555 CONFIG_SERIAL_SOFTWARE_FIFO
558 Use an interrupt handler for receiving data on the
559 serial port. It also enables using hardware handshake
560 (RTS/CTS) and UART's built-in FIFO. Set the number of
561 bytes the interrupt driven input buffer should have.
563 Leave undefined to disable this feature, including
564 disable the buffer and hardware handshake.
566 - Console UART Number:
570 If defined internal UART1 (and not UART0) is used
571 as default U-Boot console.
573 - Boot Delay: CONFIG_BOOTDELAY - in seconds
574 Delay before automatically booting the default image;
575 set to -1 to disable autoboot.
577 See doc/README.autoboot for these options that
578 work with CONFIG_BOOTDELAY. None are required.
579 CONFIG_BOOT_RETRY_TIME
580 CONFIG_BOOT_RETRY_MIN
581 CONFIG_AUTOBOOT_KEYED
582 CONFIG_AUTOBOOT_PROMPT
583 CONFIG_AUTOBOOT_DELAY_STR
584 CONFIG_AUTOBOOT_STOP_STR
585 CONFIG_AUTOBOOT_DELAY_STR2
586 CONFIG_AUTOBOOT_STOP_STR2
587 CONFIG_ZERO_BOOTDELAY_CHECK
588 CONFIG_RESET_TO_RETRY
592 Only needed when CONFIG_BOOTDELAY is enabled;
593 define a command string that is automatically executed
594 when no character is read on the console interface
595 within "Boot Delay" after reset.
598 This can be used to pass arguments to the bootm
599 command. The value of CONFIG_BOOTARGS goes into the
600 environment value "bootargs".
602 CONFIG_RAMBOOT and CONFIG_NFSBOOT
603 The value of these goes into the environment as
604 "ramboot" and "nfsboot" respectively, and can be used
605 as a convenience, when switching between booting from
611 When this option is #defined, the existence of the
612 environment variable "preboot" will be checked
613 immediately before starting the CONFIG_BOOTDELAY
614 countdown and/or running the auto-boot command resp.
615 entering interactive mode.
617 This feature is especially useful when "preboot" is
618 automatically generated or modified. For an example
619 see the LWMON board specific code: here "preboot" is
620 modified when the user holds down a certain
621 combination of keys on the (special) keyboard when
624 - Serial Download Echo Mode:
626 If defined to 1, all characters received during a
627 serial download (using the "loads" command) are
628 echoed back. This might be needed by some terminal
629 emulations (like "cu"), but may as well just take
630 time on others. This setting #define's the initial
631 value of the "loads_echo" environment variable.
633 - Kgdb Serial Baudrate: (if CFG_CMD_KGDB is defined)
635 Select one of the baudrates listed in
636 CFG_BAUDRATE_TABLE, see below.
640 Most monitor functions can be selected (or
641 de-selected) by adjusting the definition of
642 CONFIG_COMMANDS; to select individual functions,
643 #define CONFIG_COMMANDS by "OR"ing any of the
646 #define enables commands:
647 -------------------------
648 CFG_CMD_ASKENV * ask for env variable
649 CFG_CMD_AUTOSCRIPT Autoscript Support
651 CFG_CMD_BEDBUG * Include BedBug Debugger
652 CFG_CMD_BMP * BMP support
653 CFG_CMD_BSP * Board specific commands
655 CFG_CMD_CACHE * icache, dcache
656 CFG_CMD_CONSOLE coninfo
657 CFG_CMD_DATE * support for RTC, date/time...
658 CFG_CMD_DHCP * DHCP support
659 CFG_CMD_DIAG * Diagnostics
660 CFG_CMD_DOC * Disk-On-Chip Support
661 CFG_CMD_DTT * Digital Therm and Thermostat
662 CFG_CMD_ECHO echo arguments
663 CFG_CMD_EEPROM * EEPROM read/write support
664 CFG_CMD_ELF * bootelf, bootvx
666 CFG_CMD_FDC * Floppy Disk Support
667 CFG_CMD_FAT * FAT partition support
668 CFG_CMD_FDOS * Dos diskette Support
669 CFG_CMD_FLASH flinfo, erase, protect
670 CFG_CMD_FPGA FPGA device initialization support
671 CFG_CMD_HWFLOW * RTS/CTS hw flow control
672 CFG_CMD_I2C * I2C serial bus support
673 CFG_CMD_IDE * IDE harddisk support
675 CFG_CMD_IMLS List all found images
676 CFG_CMD_IMMAP * IMMR dump support
677 CFG_CMD_IRQ * irqinfo
678 CFG_CMD_ITEST Integer/string test of 2 values
679 CFG_CMD_JFFS2 * JFFS2 Support
683 CFG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
685 CFG_CMD_MISC Misc functions like sleep etc
686 CFG_CMD_MMC * MMC memory mapped support
687 CFG_CMD_MII * MII utility commands
688 CFG_CMD_NAND * NAND support
689 CFG_CMD_NET bootp, tftpboot, rarpboot
690 CFG_CMD_PCI * pciinfo
691 CFG_CMD_PCMCIA * PCMCIA support
692 CFG_CMD_PING * send ICMP ECHO_REQUEST to network host
693 CFG_CMD_PORTIO * Port I/O
694 CFG_CMD_REGINFO * Register dump
695 CFG_CMD_RUN run command in env variable
696 CFG_CMD_SAVES * save S record dump
697 CFG_CMD_SCSI * SCSI Support
698 CFG_CMD_SDRAM * print SDRAM configuration information
699 (requires CFG_CMD_I2C)
700 CFG_CMD_SETGETDCR Support for DCR Register access (4xx only)
701 CFG_CMD_SPI * SPI serial bus support
702 CFG_CMD_USB * USB support
703 CFG_CMD_VFD * VFD support (TRAB)
704 CFG_CMD_BSP * Board SPecific functions
705 CFG_CMD_CDP * Cisco Discover Protocol support
706 -----------------------------------------------
709 CONFIG_CMD_DFL Default configuration; at the moment
710 this is includes all commands, except
711 the ones marked with "*" in the list
714 If you don't define CONFIG_COMMANDS it defaults to
715 CONFIG_CMD_DFL in include/cmd_confdefs.h. A board can
716 override the default settings in the respective
719 EXAMPLE: If you want all functions except of network
720 support you can write:
722 #define CONFIG_COMMANDS (CFG_CMD_ALL & ~CFG_CMD_NET)
725 Note: Don't enable the "icache" and "dcache" commands
726 (configuration option CFG_CMD_CACHE) unless you know
727 what you (and your U-Boot users) are doing. Data
728 cache cannot be enabled on systems like the 8xx or
729 8260 (where accesses to the IMMR region must be
730 uncached), and it cannot be disabled on all other
731 systems where we (mis-) use the data cache to hold an
732 initial stack and some data.
735 XXX - this list needs to get updated!
739 If this variable is defined, it enables watchdog
740 support. There must be support in the platform specific
741 code for a watchdog. For the 8xx and 8260 CPUs, the
742 SIU Watchdog feature is enabled in the SYPCR
746 CONFIG_VERSION_VARIABLE
747 If this variable is defined, an environment variable
748 named "ver" is created by U-Boot showing the U-Boot
749 version as printed by the "version" command.
750 This variable is readonly.
754 When CFG_CMD_DATE is selected, the type of the RTC
755 has to be selected, too. Define exactly one of the
758 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
759 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
760 CONFIG_RTC_MC146818 - use MC146818 RTC
761 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
762 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
763 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
764 CONFIG_RTC_DS164x - use Dallas DS164x RTC
765 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
767 Note that if the RTC uses I2C, then the I2C interface
768 must also be configured. See I2C Support, below.
772 When CONFIG_TIMESTAMP is selected, the timestamp
773 (date and time) of an image is printed by image
774 commands like bootm or iminfo. This option is
775 automatically enabled when you select CFG_CMD_DATE .
778 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
779 and/or CONFIG_ISO_PARTITION
781 If IDE or SCSI support is enabled (CFG_CMD_IDE or
782 CFG_CMD_SCSI) you must configure support for at least
783 one partition type as well.
786 CONFIG_IDE_RESET_ROUTINE - this is defined in several
787 board configurations files but used nowhere!
789 CONFIG_IDE_RESET - is this is defined, IDE Reset will
790 be performed by calling the function
791 ide_set_reset(int reset)
792 which has to be defined in a board specific file
797 Set this to enable ATAPI support.
802 Set this to enable support for disks larger than 137GB
803 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
804 Whithout these , LBA48 support uses 32bit variables and will 'only'
805 support disks up to 2.1TB.
808 When enabled, makes the IDE subsystem use 64bit sector addresses.
812 At the moment only there is only support for the
813 SYM53C8XX SCSI controller; define
814 CONFIG_SCSI_SYM53C8XX to enable it.
816 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
817 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
818 CFG_SCSI_MAX_LUN] can be adjusted to define the
819 maximum numbers of LUNs, SCSI ID's and target
821 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
823 - NETWORK Support (PCI):
825 Support for Intel 8254x gigabit chips.
828 Support for Intel 82557/82559/82559ER chips.
829 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
830 write routine for first time initialisation.
833 Support for Digital 2114x chips.
834 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
835 modem chip initialisation (KS8761/QS6611).
838 Support for National dp83815 chips.
841 Support for National dp8382[01] gigabit chips.
843 - NETWORK Support (other):
845 CONFIG_DRIVER_LAN91C96
846 Support for SMSC's LAN91C96 chips.
849 Define this to hold the physical address
850 of the LAN91C96's I/O space
852 CONFIG_LAN91C96_USE_32_BIT
853 Define this to enable 32 bit addressing
855 CONFIG_DRIVER_SMC91111
856 Support for SMSC's LAN91C111 chip
859 Define this to hold the physical address
860 of the device (I/O space)
862 CONFIG_SMC_USE_32_BIT
863 Define this if data bus is 32 bits
865 CONFIG_SMC_USE_IOFUNCS
866 Define this to use i/o functions instead of macros
867 (some hardware wont work with macros)
870 At the moment only the UHCI host controller is
871 supported (PIP405, MIP405, MPC5200); define
872 CONFIG_USB_UHCI to enable it.
873 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
874 and define CONFIG_USB_STORAGE to enable the USB
877 Supported are USB Keyboards and USB Floppy drives
879 MPC5200 USB requires additional defines:
881 for 528 MHz Clock: 0x0001bbbb
883 for differential drivers: 0x00001000
884 for single ended drivers: 0x00005000
888 The MMC controller on the Intel PXA is supported. To
889 enable this define CONFIG_MMC. The MMC can be
890 accessed from the boot prompt by mapping the device
891 to physical memory similar to flash. Command line is
892 enabled with CFG_CMD_MMC. The MMC driver also works with
893 the FAT fs. This is enabled with CFG_CMD_FAT.
895 - Journaling Flash filesystem support:
896 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
897 CONFIG_JFFS2_NAND_DEV
898 Define these for a default partition on a NAND device
900 CFG_JFFS2_FIRST_SECTOR,
901 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
902 Define these for a default partition on a NOR device
905 Define this to create an own partition. You have to provide a
906 function struct part_info* jffs2_part_info(int part_num)
908 If you define only one JFFS2 partition you may also want to
909 #define CFG_JFFS_SINGLE_PART 1
910 to disable the command chpart. This is the default when you
911 have not defined a custom partition
916 Define this to enable standard (PC-Style) keyboard
920 Standard PC keyboard driver with US (is default) and
921 GERMAN key layout (switch via environment 'keymap=de') support.
922 Export function i8042_kbd_init, i8042_tstc and i8042_getc
923 for cfb_console. Supports cursor blinking.
928 Define this to enable video support (for output to
933 Enable Chips & Technologies 69000 Video chip
935 CONFIG_VIDEO_SMI_LYNXEM
936 Enable Silicon Motion SMI 712/710/810 Video chip. The
937 video output is selected via environment 'videoout'
938 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
941 For the CT69000 and SMI_LYNXEM drivers, videomode is
942 selected via environment 'videomode'. Two diferent ways
944 - "videomode=num" 'num' is a standard LiLo mode numbers.
945 Following standard modes are supported (* is default):
947 Colors 640x480 800x600 1024x768 1152x864 1280x1024
948 -------------+---------------------------------------------
949 8 bits | 0x301* 0x303 0x305 0x161 0x307
950 15 bits | 0x310 0x313 0x316 0x162 0x319
951 16 bits | 0x311 0x314 0x317 0x163 0x31A
952 24 bits | 0x312 0x315 0x318 ? 0x31B
953 -------------+---------------------------------------------
954 (i.e. setenv videomode 317; saveenv; reset;)
956 - "videomode=bootargs" all the video parameters are parsed
957 from the bootargs. (See drivers/videomodes.c)
960 CONFIG_VIDEO_SED13806
961 Enable Epson SED13806 driver. This driver supports 8bpp
962 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
963 or CONFIG_VIDEO_SED13806_16BPP
968 Define this to enable a custom keyboard support.
969 This simply calls drv_keyboard_init() which must be
970 defined in your board-specific files.
971 The only board using this so far is RBC823.
973 - LCD Support: CONFIG_LCD
975 Define this to enable LCD support (for output to LCD
976 display); also select one of the supported displays
977 by defining one of these:
979 CONFIG_NEC_NL6448AC33:
981 NEC NL6448AC33-18. Active, color, single scan.
983 CONFIG_NEC_NL6448BC20
985 NEC NL6448BC20-08. 6.5", 640x480.
986 Active, color, single scan.
988 CONFIG_NEC_NL6448BC33_54
990 NEC NL6448BC33-54. 10.4", 640x480.
991 Active, color, single scan.
995 Sharp 320x240. Active, color, single scan.
996 It isn't 16x9, and I am not sure what it is.
998 CONFIG_SHARP_LQ64D341
1000 Sharp LQ64D341 display, 640x480.
1001 Active, color, single scan.
1005 HLD1045 display, 640x480.
1006 Active, color, single scan.
1010 Optrex CBL50840-2 NF-FW 99 22 M5
1012 Hitachi LMG6912RPFC-00T
1016 320x240. Black & white.
1018 Normally display is black on white background; define
1019 CFG_WHITE_ON_BLACK to get it inverted.
1021 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1023 If this option is set, the environment is checked for
1024 a variable "splashimage". If found, the usual display
1025 of logo, copyright and system information on the LCD
1026 is suppressed and the BMP image at the address
1027 specified in "splashimage" is loaded instead. The
1028 console is redirected to the "nulldev", too. This
1029 allows for a "silent" boot where a splash screen is
1030 loaded very quickly after power-on.
1032 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1034 If this option is set, additionally to standard BMP
1035 images, gzipped BMP images can be displayed via the
1036 splashscreen support or the bmp command.
1038 - Compression support:
1041 If this option is set, support for bzip2 compressed
1042 images is included. If not, only uncompressed and gzip
1043 compressed images are supported.
1045 NOTE: the bzip2 algorithm requires a lot of RAM, so
1046 the malloc area (as defined by CFG_MALLOC_LEN) should
1052 The address of PHY on MII bus.
1054 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1056 The clock frequency of the MII bus
1060 If this option is set, support for speed/duplex
1061 detection of Gigabit PHY is included.
1063 CONFIG_PHY_RESET_DELAY
1065 Some PHY like Intel LXT971A need extra delay after
1066 reset before any MII register access is possible.
1067 For such PHY, set this option to the usec delay
1068 required. (minimum 300usec for LXT971A)
1070 CONFIG_PHY_CMD_DELAY (ppc4xx)
1072 Some PHY like Intel LXT971A need extra delay after
1073 command issued before MII status register can be read
1080 Define a default value for ethernet address to use
1081 for the respective ethernet interface, in case this
1082 is not determined automatically.
1087 Define a default value for the IP address to use for
1088 the default ethernet interface, in case this is not
1089 determined through e.g. bootp.
1091 - Server IP address:
1094 Defines a default value for theIP address of a TFTP
1095 server to contact when using the "tftboot" command.
1097 - BOOTP Recovery Mode:
1098 CONFIG_BOOTP_RANDOM_DELAY
1100 If you have many targets in a network that try to
1101 boot using BOOTP, you may want to avoid that all
1102 systems send out BOOTP requests at precisely the same
1103 moment (which would happen for instance at recovery
1104 from a power failure, when all systems will try to
1105 boot, thus flooding the BOOTP server. Defining
1106 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1107 inserted before sending out BOOTP requests. The
1108 following delays are insterted then:
1110 1st BOOTP request: delay 0 ... 1 sec
1111 2nd BOOTP request: delay 0 ... 2 sec
1112 3rd BOOTP request: delay 0 ... 4 sec
1114 BOOTP requests: delay 0 ... 8 sec
1116 - DHCP Advanced Options:
1119 You can fine tune the DHCP functionality by adding
1120 these flags to the CONFIG_BOOTP_MASK define:
1122 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1123 serverip from a DHCP server, it is possible that more
1124 than one DNS serverip is offered to the client.
1125 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1126 serverip will be stored in the additional environment
1127 variable "dnsip2". The first DNS serverip is always
1128 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1129 is added to the CONFIG_BOOTP_MASK.
1131 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1132 to do a dynamic update of a DNS server. To do this, they
1133 need the hostname of the DHCP requester.
1134 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1135 CONFIG_BOOTP_MASK, the content of the "hostname"
1136 environment variable is passed as option 12 to
1140 CONFIG_CDP_DEVICE_ID
1142 The device id used in CDP trigger frames.
1144 CONFIG_CDP_DEVICE_ID_PREFIX
1146 A two character string which is prefixed to the MAC address
1151 A printf format string which contains the ascii name of
1152 the port. Normally is set to "eth%d" which sets
1153 eth0 for the first ethernet, eth1 for the second etc.
1155 CONFIG_CDP_CAPABILITIES
1157 A 32bit integer which indicates the device capabilities;
1158 0x00000010 for a normal host which does not forwards.
1162 An ascii string containing the version of the software.
1166 An ascii string containing the name of the platform.
1170 A 32bit integer sent on the trigger.
1172 CONFIG_CDP_POWER_CONSUMPTION
1174 A 16bit integer containing the power consumption of the
1175 device in .1 of milliwatts.
1177 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1179 A byte containing the id of the VLAN.
1181 - Status LED: CONFIG_STATUS_LED
1183 Several configurations allow to display the current
1184 status using a LED. For instance, the LED will blink
1185 fast while running U-Boot code, stop blinking as
1186 soon as a reply to a BOOTP request was received, and
1187 start blinking slow once the Linux kernel is running
1188 (supported by a status LED driver in the Linux
1189 kernel). Defining CONFIG_STATUS_LED enables this
1192 - CAN Support: CONFIG_CAN_DRIVER
1194 Defining CONFIG_CAN_DRIVER enables CAN driver support
1195 on those systems that support this (optional)
1196 feature, like the TQM8xxL modules.
1198 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1200 These enable I2C serial bus commands. Defining either of
1201 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1202 include the appropriate I2C driver for the selected cpu.
1204 This will allow you to use i2c commands at the u-boot
1205 command line (as long as you set CFG_CMD_I2C in
1206 CONFIG_COMMANDS) and communicate with i2c based realtime
1207 clock chips. See common/cmd_i2c.c for a description of the
1208 command line interface.
1210 CONFIG_I2C_CMD_TREE is a recommended option that places
1211 all I2C commands under a single 'i2c' root command. The
1212 older 'imm', 'imd', 'iprobe' etc. commands are considered
1213 deprecated and may disappear in the future.
1215 CONFIG_HARD_I2C selects a hardware I2C controller.
1217 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1218 bit-banging) driver instead of CPM or similar hardware
1221 There are several other quantities that must also be
1222 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1224 In both cases you will need to define CFG_I2C_SPEED
1225 to be the frequency (in Hz) at which you wish your i2c bus
1226 to run and CFG_I2C_SLAVE to be the address of this node (ie
1227 the cpu's i2c node address).
1229 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1230 sets the cpu up as a master node and so its address should
1231 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1232 p.16-473). So, set CFG_I2C_SLAVE to 0.
1234 That's all that's required for CONFIG_HARD_I2C.
1236 If you use the software i2c interface (CONFIG_SOFT_I2C)
1237 then the following macros need to be defined (examples are
1238 from include/configs/lwmon.h):
1242 (Optional). Any commands necessary to enable the I2C
1243 controller or configure ports.
1245 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1249 (Only for MPC8260 CPU). The I/O port to use (the code
1250 assumes both bits are on the same port). Valid values
1251 are 0..3 for ports A..D.
1255 The code necessary to make the I2C data line active
1256 (driven). If the data line is open collector, this
1259 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1263 The code necessary to make the I2C data line tri-stated
1264 (inactive). If the data line is open collector, this
1267 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1271 Code that returns TRUE if the I2C data line is high,
1274 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1278 If <bit> is TRUE, sets the I2C data line high. If it
1279 is FALSE, it clears it (low).
1281 eg: #define I2C_SDA(bit) \
1282 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1283 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1287 If <bit> is TRUE, sets the I2C clock line high. If it
1288 is FALSE, it clears it (low).
1290 eg: #define I2C_SCL(bit) \
1291 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1292 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1296 This delay is invoked four times per clock cycle so this
1297 controls the rate of data transfer. The data rate thus
1298 is 1 / (I2C_DELAY * 4). Often defined to be something
1301 #define I2C_DELAY udelay(2)
1305 When a board is reset during an i2c bus transfer
1306 chips might think that the current transfer is still
1307 in progress. On some boards it is possible to access
1308 the i2c SCLK line directly, either by using the
1309 processor pin as a GPIO or by having a second pin
1310 connected to the bus. If this option is defined a
1311 custom i2c_init_board() routine in boards/xxx/board.c
1312 is run early in the boot sequence.
1314 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1316 This option enables configuration of bi_iic_fast[] flags
1317 in u-boot bd_info structure based on u-boot environment
1318 variable "i2cfast". (see also i2cfast)
1320 CONFIG_I2C_MULTI_BUS
1322 This option allows the use of multiple I2C buses, each of which
1323 must have a controller. At any point in time, only one bus is
1324 active. To switch to a different bus, use the 'i2c dev' command.
1325 Note that bus numbering is zero-based.
1329 This option specifies a list of I2C devices that will be skipped
1330 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1331 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1332 pairs. Otherwise, specify a 1D array of device addresses
1335 #undef CONFIG_I2C_MULTI_BUS
1336 #define CFG_I2C_NOPROBES {0x50,0x68}
1338 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1340 #define CONFIG_I2C_MULTI_BUS
1341 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1343 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1347 If defined, then this indicates the I2C bus number for DDR SPD.
1348 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1352 Define this option if you want to use Freescale's I2C driver in
1356 - SPI Support: CONFIG_SPI
1358 Enables SPI driver (so far only tested with
1359 SPI EEPROM, also an instance works with Crystal A/D and
1360 D/As on the SACSng board)
1364 Enables extended (16-bit) SPI EEPROM addressing.
1365 (symmetrical to CONFIG_I2C_X)
1369 Enables a software (bit-bang) SPI driver rather than
1370 using hardware support. This is a general purpose
1371 driver that only requires three general I/O port pins
1372 (two outputs, one input) to function. If this is
1373 defined, the board configuration must define several
1374 SPI configuration items (port pins to use, etc). For
1375 an example, see include/configs/sacsng.h.
1377 - FPGA Support: CONFIG_FPGA_COUNT
1379 Specify the number of FPGA devices to support.
1383 Used to specify the types of FPGA devices. For example,
1384 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1386 CFG_FPGA_PROG_FEEDBACK
1388 Enable printing of hash marks during FPGA configuration.
1392 Enable checks on FPGA configuration interface busy
1393 status by the configuration function. This option
1394 will require a board or device specific function to
1399 If defined, a function that provides delays in the FPGA
1400 configuration driver.
1402 CFG_FPGA_CHECK_CTRLC
1403 Allow Control-C to interrupt FPGA configuration
1405 CFG_FPGA_CHECK_ERROR
1407 Check for configuration errors during FPGA bitfile
1408 loading. For example, abort during Virtex II
1409 configuration if the INIT_B line goes low (which
1410 indicated a CRC error).
1414 Maximum time to wait for the INIT_B line to deassert
1415 after PROB_B has been deasserted during a Virtex II
1416 FPGA configuration sequence. The default time is 500
1421 Maximum time to wait for BUSY to deassert during
1422 Virtex II FPGA configuration. The default is 5 mS.
1424 CFG_FPGA_WAIT_CONFIG
1426 Time to wait after FPGA configuration. The default is
1429 - Configuration Management:
1432 If defined, this string will be added to the U-Boot
1433 version information (U_BOOT_VERSION)
1435 - Vendor Parameter Protection:
1437 U-Boot considers the values of the environment
1438 variables "serial#" (Board Serial Number) and
1439 "ethaddr" (Ethernet Address) to be parameters that
1440 are set once by the board vendor / manufacturer, and
1441 protects these variables from casual modification by
1442 the user. Once set, these variables are read-only,
1443 and write or delete attempts are rejected. You can
1444 change this behviour:
1446 If CONFIG_ENV_OVERWRITE is #defined in your config
1447 file, the write protection for vendor parameters is
1448 completely disabled. Anybody can change or delete
1451 Alternatively, if you #define _both_ CONFIG_ETHADDR
1452 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1453 ethernet address is installed in the environment,
1454 which can be changed exactly ONCE by the user. [The
1455 serial# is unaffected by this, i. e. it remains
1461 Define this variable to enable the reservation of
1462 "protected RAM", i. e. RAM which is not overwritten
1463 by U-Boot. Define CONFIG_PRAM to hold the number of
1464 kB you want to reserve for pRAM. You can overwrite
1465 this default value by defining an environment
1466 variable "pram" to the number of kB you want to
1467 reserve. Note that the board info structure will
1468 still show the full amount of RAM. If pRAM is
1469 reserved, a new environment variable "mem" will
1470 automatically be defined to hold the amount of
1471 remaining RAM in a form that can be passed as boot
1472 argument to Linux, for instance like that:
1474 setenv bootargs ... mem=\${mem}
1477 This way you can tell Linux not to use this memory,
1478 either, which results in a memory region that will
1479 not be affected by reboots.
1481 *WARNING* If your board configuration uses automatic
1482 detection of the RAM size, you must make sure that
1483 this memory test is non-destructive. So far, the
1484 following board configurations are known to be
1487 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1488 HERMES, IP860, RPXlite, LWMON, LANTEC,
1489 PCU_E, FLAGADM, TQM8260
1494 Define this variable to stop the system in case of a
1495 fatal error, so that you have to reset it manually.
1496 This is probably NOT a good idea for an embedded
1497 system where you want to system to reboot
1498 automatically as fast as possible, but it may be
1499 useful during development since you can try to debug
1500 the conditions that lead to the situation.
1502 CONFIG_NET_RETRY_COUNT
1504 This variable defines the number of retries for
1505 network operations like ARP, RARP, TFTP, or BOOTP
1506 before giving up the operation. If not defined, a
1507 default value of 5 is used.
1509 - Command Interpreter:
1510 CONFIG_AUTO_COMPLETE
1512 Enable auto completion of commands using TAB.
1514 Note that this feature has NOT been implemented yet
1515 for the "hush" shell.
1520 Define this variable to enable the "hush" shell (from
1521 Busybox) as command line interpreter, thus enabling
1522 powerful command line syntax like
1523 if...then...else...fi conditionals or `&&' and '||'
1524 constructs ("shell scripts").
1526 If undefined, you get the old, much simpler behaviour
1527 with a somewhat smaller memory footprint.
1532 This defines the secondary prompt string, which is
1533 printed when the command interpreter needs more input
1534 to complete a command. Usually "> ".
1538 In the current implementation, the local variables
1539 space and global environment variables space are
1540 separated. Local variables are those you define by
1541 simply typing `name=value'. To access a local
1542 variable later on, you have write `$name' or
1543 `${name}'; to execute the contents of a variable
1544 directly type `$name' at the command prompt.
1546 Global environment variables are those you use
1547 setenv/printenv to work with. To run a command stored
1548 in such a variable, you need to use the run command,
1549 and you must not use the '$' sign to access them.
1551 To store commands and special characters in a
1552 variable, please use double quotation marks
1553 surrounding the whole text of the variable, instead
1554 of the backslashes before semicolons and special
1557 - Commandline Editing and History:
1558 CONFIG_CMDLINE_EDITING
1560 Enable editiong and History functions for interactive
1561 commandline input operations
1563 - Default Environment:
1564 CONFIG_EXTRA_ENV_SETTINGS
1566 Define this to contain any number of null terminated
1567 strings (variable = value pairs) that will be part of
1568 the default environment compiled into the boot image.
1570 For example, place something like this in your
1571 board's config file:
1573 #define CONFIG_EXTRA_ENV_SETTINGS \
1577 Warning: This method is based on knowledge about the
1578 internal format how the environment is stored by the
1579 U-Boot code. This is NOT an official, exported
1580 interface! Although it is unlikely that this format
1581 will change soon, there is no guarantee either.
1582 You better know what you are doing here.
1584 Note: overly (ab)use of the default environment is
1585 discouraged. Make sure to check other ways to preset
1586 the environment like the autoscript function or the
1589 - DataFlash Support:
1590 CONFIG_HAS_DATAFLASH
1592 Defining this option enables DataFlash features and
1593 allows to read/write in Dataflash via the standard
1596 - SystemACE Support:
1599 Adding this option adds support for Xilinx SystemACE
1600 chips attached via some sort of local bus. The address
1601 of the chip must alsh be defined in the
1602 CFG_SYSTEMACE_BASE macro. For example:
1604 #define CONFIG_SYSTEMACE
1605 #define CFG_SYSTEMACE_BASE 0xf0000000
1607 When SystemACE support is added, the "ace" device type
1608 becomes available to the fat commands, i.e. fatls.
1610 - TFTP Fixed UDP Port:
1613 If this is defined, the environment variable tftpsrcp
1614 is used to supply the TFTP UDP source port value.
1615 If tftpsrcp isn't defined, the normal pseudo-random port
1616 number generator is used.
1618 Also, the environment variable tftpdstp is used to supply
1619 the TFTP UDP destination port value. If tftpdstp isn't
1620 defined, the normal port 69 is used.
1622 The purpose for tftpsrcp is to allow a TFTP server to
1623 blindly start the TFTP transfer using the pre-configured
1624 target IP address and UDP port. This has the effect of
1625 "punching through" the (Windows XP) firewall, allowing
1626 the remainder of the TFTP transfer to proceed normally.
1627 A better solution is to properly configure the firewall,
1628 but sometimes that is not allowed.
1630 - Show boot progress:
1631 CONFIG_SHOW_BOOT_PROGRESS
1633 Defining this option allows to add some board-
1634 specific code (calling a user-provided function
1635 "show_boot_progress(int)") that enables you to show
1636 the system's boot progress on some display (for
1637 example, some LED's) on your board. At the moment,
1638 the following checkpoints are implemented:
1641 1 common/cmd_bootm.c before attempting to boot an image
1642 -1 common/cmd_bootm.c Image header has bad magic number
1643 2 common/cmd_bootm.c Image header has correct magic number
1644 -2 common/cmd_bootm.c Image header has bad checksum
1645 3 common/cmd_bootm.c Image header has correct checksum
1646 -3 common/cmd_bootm.c Image data has bad checksum
1647 4 common/cmd_bootm.c Image data has correct checksum
1648 -4 common/cmd_bootm.c Image is for unsupported architecture
1649 5 common/cmd_bootm.c Architecture check OK
1650 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1651 6 common/cmd_bootm.c Image Type check OK
1652 -6 common/cmd_bootm.c gunzip uncompression error
1653 -7 common/cmd_bootm.c Unimplemented compression type
1654 7 common/cmd_bootm.c Uncompression OK
1655 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1656 8 common/cmd_bootm.c Image Type check OK
1657 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1658 9 common/cmd_bootm.c Start initial ramdisk verification
1659 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1660 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1661 10 common/cmd_bootm.c Ramdisk header is OK
1662 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1663 11 common/cmd_bootm.c Ramdisk data has correct checksum
1664 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1665 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1666 13 common/cmd_bootm.c Start multifile image verification
1667 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1668 15 common/cmd_bootm.c All preparation done, transferring control to OS
1670 -30 lib_ppc/board.c Fatal error, hang the system
1671 -31 post/post.c POST test failed, detected by post_output_backlog()
1672 -32 post/post.c POST test failed, detected by post_run_single()
1674 -1 common/cmd_doc.c Bad usage of "doc" command
1675 -1 common/cmd_doc.c No boot device
1676 -1 common/cmd_doc.c Unknown Chip ID on boot device
1677 -1 common/cmd_doc.c Read Error on boot device
1678 -1 common/cmd_doc.c Image header has bad magic number
1680 -1 common/cmd_ide.c Bad usage of "ide" command
1681 -1 common/cmd_ide.c No boot device
1682 -1 common/cmd_ide.c Unknown boot device
1683 -1 common/cmd_ide.c Unknown partition table
1684 -1 common/cmd_ide.c Invalid partition type
1685 -1 common/cmd_ide.c Read Error on boot device
1686 -1 common/cmd_ide.c Image header has bad magic number
1688 -1 common/cmd_nand.c Bad usage of "nand" command
1689 -1 common/cmd_nand.c No boot device
1690 -1 common/cmd_nand.c Unknown Chip ID on boot device
1691 -1 common/cmd_nand.c Read Error on boot device
1692 -1 common/cmd_nand.c Image header has bad magic number
1694 -1 common/env_common.c Environment has a bad CRC, using default
1700 [so far only for SMDK2400 and TRAB boards]
1702 - Modem support endable:
1703 CONFIG_MODEM_SUPPORT
1705 - RTS/CTS Flow control enable:
1708 - Modem debug support:
1709 CONFIG_MODEM_SUPPORT_DEBUG
1711 Enables debugging stuff (char screen[1024], dbg())
1712 for modem support. Useful only with BDI2000.
1714 - Interrupt support (PPC):
1716 There are common interrupt_init() and timer_interrupt()
1717 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1718 for cpu specific initialization. interrupt_init_cpu()
1719 should set decrementer_count to appropriate value. If
1720 cpu resets decrementer automatically after interrupt
1721 (ppc4xx) it should set decrementer_count to zero.
1722 timer_interrupt() calls timer_interrupt_cpu() for cpu
1723 specific handling. If board has watchdog / status_led
1724 / other_activity_monitor it works automatically from
1725 general timer_interrupt().
1729 In the target system modem support is enabled when a
1730 specific key (key combination) is pressed during
1731 power-on. Otherwise U-Boot will boot normally
1732 (autoboot). The key_pressed() fuction is called from
1733 board_init(). Currently key_pressed() is a dummy
1734 function, returning 1 and thus enabling modem
1737 If there are no modem init strings in the
1738 environment, U-Boot proceed to autoboot; the
1739 previous output (banner, info printfs) will be
1742 See also: doc/README.Modem
1745 Configuration Settings:
1746 -----------------------
1748 - CFG_LONGHELP: Defined when you want long help messages included;
1749 undefine this when you're short of memory.
1751 - CFG_PROMPT: This is what U-Boot prints on the console to
1752 prompt for user input.
1754 - CFG_CBSIZE: Buffer size for input from the Console
1756 - CFG_PBSIZE: Buffer size for Console output
1758 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1760 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1761 the application (usually a Linux kernel) when it is
1764 - CFG_BAUDRATE_TABLE:
1765 List of legal baudrate settings for this board.
1767 - CFG_CONSOLE_INFO_QUIET
1768 Suppress display of console information at boot.
1770 - CFG_CONSOLE_IS_IN_ENV
1771 If the board specific function
1772 extern int overwrite_console (void);
1773 returns 1, the stdin, stderr and stdout are switched to the
1774 serial port, else the settings in the environment are used.
1776 - CFG_CONSOLE_OVERWRITE_ROUTINE
1777 Enable the call to overwrite_console().
1779 - CFG_CONSOLE_ENV_OVERWRITE
1780 Enable overwrite of previous console environment settings.
1782 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1783 Begin and End addresses of the area used by the
1787 Enable an alternate, more extensive memory test.
1789 - CFG_MEMTEST_SCRATCH:
1790 Scratch address used by the alternate memory test
1791 You only need to set this if address zero isn't writeable
1793 - CFG_TFTP_LOADADDR:
1794 Default load address for network file downloads
1796 - CFG_LOADS_BAUD_CHANGE:
1797 Enable temporary baudrate change while serial download
1800 Physical start address of SDRAM. _Must_ be 0 here.
1803 Physical start address of Motherboard I/O (if using a
1807 Physical start address of Flash memory.
1810 Physical start address of boot monitor code (set by
1811 make config files to be same as the text base address
1812 (TEXT_BASE) used when linking) - same as
1813 CFG_FLASH_BASE when booting from flash.
1816 Size of memory reserved for monitor code, used to
1817 determine _at_compile_time_ (!) if the environment is
1818 embedded within the U-Boot image, or in a separate
1822 Size of DRAM reserved for malloc() use.
1825 Normally compressed uImages are limited to an
1826 uncompressed size of 8 MBytes. If this is not enough,
1827 you can define CFG_BOOTM_LEN in your board config file
1828 to adjust this setting to your needs.
1831 Maximum size of memory mapped by the startup code of
1832 the Linux kernel; all data that must be processed by
1833 the Linux kernel (bd_info, boot arguments, eventually
1834 initrd image) must be put below this limit.
1836 - CFG_MAX_FLASH_BANKS:
1837 Max number of Flash memory banks
1839 - CFG_MAX_FLASH_SECT:
1840 Max number of sectors on a Flash chip
1842 - CFG_FLASH_ERASE_TOUT:
1843 Timeout for Flash erase operations (in ms)
1845 - CFG_FLASH_WRITE_TOUT:
1846 Timeout for Flash write operations (in ms)
1848 - CFG_FLASH_LOCK_TOUT
1849 Timeout for Flash set sector lock bit operation (in ms)
1851 - CFG_FLASH_UNLOCK_TOUT
1852 Timeout for Flash clear lock bits operation (in ms)
1854 - CFG_FLASH_PROTECTION
1855 If defined, hardware flash sectors protection is used
1856 instead of U-Boot software protection.
1858 - CFG_DIRECT_FLASH_TFTP:
1860 Enable TFTP transfers directly to flash memory;
1861 without this option such a download has to be
1862 performed in two steps: (1) download to RAM, and (2)
1863 copy from RAM to flash.
1865 The two-step approach is usually more reliable, since
1866 you can check if the download worked before you erase
1867 the flash, but in some situations (when sytem RAM is
1868 too limited to allow for a tempory copy of the
1869 downloaded image) this option may be very useful.
1872 Define if the flash driver uses extra elements in the
1873 common flash structure for storing flash geometry.
1875 - CFG_FLASH_CFI_DRIVER
1876 This option also enables the building of the cfi_flash driver
1877 in the drivers directory
1879 - CFG_FLASH_QUIET_TEST
1880 If this option is defined, the common CFI flash doesn't
1881 print it's warning upon not recognized FLASH banks. This
1882 is useful, if some of the configured banks are only
1883 optionally available.
1885 - CFG_RX_ETH_BUFFER:
1886 Defines the number of ethernet receive buffers. On some
1887 ethernet controllers it is recommended to set this value
1888 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1889 buffers can be full shortly after enabling the interface
1890 on high ethernet traffic.
1891 Defaults to 4 if not defined.
1893 The following definitions that deal with the placement and management
1894 of environment data (variable area); in general, we support the
1895 following configurations:
1897 - CFG_ENV_IS_IN_FLASH:
1899 Define this if the environment is in flash memory.
1901 a) The environment occupies one whole flash sector, which is
1902 "embedded" in the text segment with the U-Boot code. This
1903 happens usually with "bottom boot sector" or "top boot
1904 sector" type flash chips, which have several smaller
1905 sectors at the start or the end. For instance, such a
1906 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1907 such a case you would place the environment in one of the
1908 4 kB sectors - with U-Boot code before and after it. With
1909 "top boot sector" type flash chips, you would put the
1910 environment in one of the last sectors, leaving a gap
1911 between U-Boot and the environment.
1915 Offset of environment data (variable area) to the
1916 beginning of flash memory; for instance, with bottom boot
1917 type flash chips the second sector can be used: the offset
1918 for this sector is given here.
1920 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1924 This is just another way to specify the start address of
1925 the flash sector containing the environment (instead of
1928 - CFG_ENV_SECT_SIZE:
1930 Size of the sector containing the environment.
1933 b) Sometimes flash chips have few, equal sized, BIG sectors.
1934 In such a case you don't want to spend a whole sector for
1939 If you use this in combination with CFG_ENV_IS_IN_FLASH
1940 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1941 of this flash sector for the environment. This saves
1942 memory for the RAM copy of the environment.
1944 It may also save flash memory if you decide to use this
1945 when your environment is "embedded" within U-Boot code,
1946 since then the remainder of the flash sector could be used
1947 for U-Boot code. It should be pointed out that this is
1948 STRONGLY DISCOURAGED from a robustness point of view:
1949 updating the environment in flash makes it always
1950 necessary to erase the WHOLE sector. If something goes
1951 wrong before the contents has been restored from a copy in
1952 RAM, your target system will be dead.
1954 - CFG_ENV_ADDR_REDUND
1957 These settings describe a second storage area used to hold
1958 a redundand copy of the environment data, so that there is
1959 a valid backup copy in case there is a power failure during
1960 a "saveenv" operation.
1962 BE CAREFUL! Any changes to the flash layout, and some changes to the
1963 source code will make it necessary to adapt <board>/u-boot.lds*
1967 - CFG_ENV_IS_IN_NVRAM:
1969 Define this if you have some non-volatile memory device
1970 (NVRAM, battery buffered SRAM) which you want to use for the
1976 These two #defines are used to determin the memory area you
1977 want to use for environment. It is assumed that this memory
1978 can just be read and written to, without any special
1981 BE CAREFUL! The first access to the environment happens quite early
1982 in U-Boot initalization (when we try to get the setting of for the
1983 console baudrate). You *MUST* have mappend your NVRAM area then, or
1986 Please note that even with NVRAM we still use a copy of the
1987 environment in RAM: we could work on NVRAM directly, but we want to
1988 keep settings there always unmodified except somebody uses "saveenv"
1989 to save the current settings.
1992 - CFG_ENV_IS_IN_EEPROM:
1994 Use this if you have an EEPROM or similar serial access
1995 device and a driver for it.
2000 These two #defines specify the offset and size of the
2001 environment area within the total memory of your EEPROM.
2003 - CFG_I2C_EEPROM_ADDR:
2004 If defined, specified the chip address of the EEPROM device.
2005 The default address is zero.
2007 - CFG_EEPROM_PAGE_WRITE_BITS:
2008 If defined, the number of bits used to address bytes in a
2009 single page in the EEPROM device. A 64 byte page, for example
2010 would require six bits.
2012 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2013 If defined, the number of milliseconds to delay between
2014 page writes. The default is zero milliseconds.
2016 - CFG_I2C_EEPROM_ADDR_LEN:
2017 The length in bytes of the EEPROM memory array address. Note
2018 that this is NOT the chip address length!
2020 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2021 EEPROM chips that implement "address overflow" are ones
2022 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2023 address and the extra bits end up in the "chip address" bit
2024 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2027 Note that we consider the length of the address field to
2028 still be one byte because the extra address bits are hidden
2029 in the chip address.
2032 The size in bytes of the EEPROM device.
2035 - CFG_ENV_IS_IN_DATAFLASH:
2037 Define this if you have a DataFlash memory device which you
2038 want to use for the environment.
2044 These three #defines specify the offset and size of the
2045 environment area within the total memory of your DataFlash placed
2046 at the specified address.
2048 - CFG_ENV_IS_IN_NAND:
2050 Define this if you have a NAND device which you want to use
2051 for the environment.
2056 These two #defines specify the offset and size of the environment
2057 area within the first NAND device.
2059 - CFG_ENV_OFFSET_REDUND
2061 This setting describes a second storage area of CFG_ENV_SIZE
2062 size used to hold a redundant copy of the environment data,
2063 so that there is a valid backup copy in case there is a
2064 power failure during a "saveenv" operation.
2066 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2067 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2068 the NAND devices block size.
2070 - CFG_SPI_INIT_OFFSET
2072 Defines offset to the initial SPI buffer area in DPRAM. The
2073 area is used at an early stage (ROM part) if the environment
2074 is configured to reside in the SPI EEPROM: We need a 520 byte
2075 scratch DPRAM area. It is used between the two initialization
2076 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2077 to be a good choice since it makes it far enough from the
2078 start of the data area as well as from the stack pointer.
2080 Please note that the environment is read-only as long as the monitor
2081 has been relocated to RAM and a RAM copy of the environment has been
2082 created; also, when using EEPROM you will have to use getenv_r()
2083 until then to read environment variables.
2085 The environment is protected by a CRC32 checksum. Before the monitor
2086 is relocated into RAM, as a result of a bad CRC you will be working
2087 with the compiled-in default environment - *silently*!!! [This is
2088 necessary, because the first environment variable we need is the
2089 "baudrate" setting for the console - if we have a bad CRC, we don't
2090 have any device yet where we could complain.]
2092 Note: once the monitor has been relocated, then it will complain if
2093 the default environment is used; a new CRC is computed as soon as you
2094 use the "saveenv" command to store a valid environment.
2096 - CFG_FAULT_ECHO_LINK_DOWN:
2097 Echo the inverted Ethernet link state to the fault LED.
2099 Note: If this option is active, then CFG_FAULT_MII_ADDR
2100 also needs to be defined.
2102 - CFG_FAULT_MII_ADDR:
2103 MII address of the PHY to check for the Ethernet link state.
2105 - CFG_64BIT_VSPRINTF:
2106 Makes vsprintf (and all *printf functions) support printing
2107 of 64bit values by using the L quantifier
2109 - CFG_64BIT_STRTOUL:
2110 Adds simple_strtoull that returns a 64bit value
2112 Low Level (hardware related) configuration options:
2113 ---------------------------------------------------
2115 - CFG_CACHELINE_SIZE:
2116 Cache Line Size of the CPU.
2119 Default address of the IMMR after system reset.
2121 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2122 and RPXsuper) to be able to adjust the position of
2123 the IMMR register after a reset.
2125 - Floppy Disk Support:
2126 CFG_FDC_DRIVE_NUMBER
2128 the default drive number (default value 0)
2132 defines the spacing between fdc chipset registers
2137 defines the offset of register from address. It
2138 depends on which part of the data bus is connected to
2139 the fdc chipset. (default value 0)
2141 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2142 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2145 if CFG_FDC_HW_INIT is defined, then the function
2146 fdc_hw_init() is called at the beginning of the FDC
2147 setup. fdc_hw_init() must be provided by the board
2148 source code. It is used to make hardware dependant
2151 - CFG_IMMR: Physical address of the Internal Memory.
2152 DO NOT CHANGE unless you know exactly what you're
2153 doing! (11-4) [MPC8xx/82xx systems only]
2155 - CFG_INIT_RAM_ADDR:
2157 Start address of memory area that can be used for
2158 initial data and stack; please note that this must be
2159 writable memory that is working WITHOUT special
2160 initialization, i. e. you CANNOT use normal RAM which
2161 will become available only after programming the
2162 memory controller and running certain initialization
2165 U-Boot uses the following memory types:
2166 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2167 - MPC824X: data cache
2168 - PPC4xx: data cache
2170 - CFG_GBL_DATA_OFFSET:
2172 Offset of the initial data structure in the memory
2173 area defined by CFG_INIT_RAM_ADDR. Usually
2174 CFG_GBL_DATA_OFFSET is chosen such that the initial
2175 data is located at the end of the available space
2176 (sometimes written as (CFG_INIT_RAM_END -
2177 CFG_INIT_DATA_SIZE), and the initial stack is just
2178 below that area (growing from (CFG_INIT_RAM_ADDR +
2179 CFG_GBL_DATA_OFFSET) downward.
2182 On the MPC824X (or other systems that use the data
2183 cache for initial memory) the address chosen for
2184 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2185 point to an otherwise UNUSED address space between
2186 the top of RAM and the start of the PCI space.
2188 - CFG_SIUMCR: SIU Module Configuration (11-6)
2190 - CFG_SYPCR: System Protection Control (11-9)
2192 - CFG_TBSCR: Time Base Status and Control (11-26)
2194 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2196 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2198 - CFG_SCCR: System Clock and reset Control Register (15-27)
2200 - CFG_OR_TIMING_SDRAM:
2204 periodic timer for refresh
2206 - CFG_DER: Debug Event Register (37-47)
2208 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2209 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2210 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2212 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2214 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2215 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2216 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2217 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2219 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2220 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2221 Machine Mode Register and Memory Periodic Timer
2222 Prescaler definitions (SDRAM timing)
2224 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2225 enable I2C microcode relocation patch (MPC8xx);
2226 define relocation offset in DPRAM [DSP2]
2228 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2229 enable SPI microcode relocation patch (MPC8xx);
2230 define relocation offset in DPRAM [SCC4]
2233 Use OSCM clock mode on MBX8xx board. Be careful,
2234 wrong setting might damage your board. Read
2235 doc/README.MBX before setting this variable!
2237 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2238 Offset of the bootmode word in DPRAM used by post
2239 (Power On Self Tests). This definition overrides
2240 #define'd default value in commproc.h resp.
2243 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2244 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2245 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2246 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2247 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2248 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2249 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2250 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2251 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2254 Get DDR timing information from an I2C EEPROM. Common with pluggable
2255 memory modules such as SODIMMs
2257 I2C address of the SPD EEPROM
2260 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2261 Note that the value must resolve to something your driver can deal with.
2263 - CFG_83XX_DDR_USES_CS0
2264 Only for 83xx systems. If specified, then DDR should be configured
2265 using CS0 and CS1 instead of CS2 and CS3.
2267 - CFG_83XX_DDR_USES_CS0
2268 Only for 83xx systems. If specified, then DDR should be configured
2269 using CS0 and CS1 instead of CS2 and CS3.
2271 - CONFIG_ETHER_ON_FEC[12]
2272 Define to enable FEC[12] on a 8xx series processor.
2274 - CONFIG_FEC[12]_PHY
2275 Define to the hardcoded PHY address which corresponds
2276 to the given FEC; i. e.
2277 #define CONFIG_FEC1_PHY 4
2278 means that the PHY with address 4 is connected to FEC1
2280 When set to -1, means to probe for first available.
2282 - CONFIG_FEC[12]_PHY_NORXERR
2283 The PHY does not have a RXERR line (RMII only).
2284 (so program the FEC to ignore it).
2287 Enable RMII mode for all FECs.
2288 Note that this is a global option, we can't
2289 have one FEC in standard MII mode and another in RMII mode.
2291 - CONFIG_CRC32_VERIFY
2292 Add a verify option to the crc32 command.
2295 => crc32 -v <address> <count> <crc32>
2297 Where address/count indicate a memory area
2298 and crc32 is the correct crc32 which the
2302 Add the "loopw" memory command. This only takes effect if
2303 the memory commands are activated globally (CFG_CMD_MEM).
2306 Add the "mdc" and "mwc" memory commands. These are cyclic
2311 This command will print 4 bytes (10,11,12,13) each 500 ms.
2313 => mwc.l 100 12345678 10
2314 This command will write 12345678 to address 100 all 10 ms.
2316 This only takes effect if the memory commands are activated
2317 globally (CFG_CMD_MEM).
2319 - CONFIG_SKIP_LOWLEVEL_INIT
2320 - CONFIG_SKIP_RELOCATE_UBOOT
2322 [ARM only] If these variables are defined, then
2323 certain low level initializations (like setting up
2324 the memory controller) are omitted and/or U-Boot does
2325 not relocate itself into RAM.
2326 Normally these variables MUST NOT be defined. The
2327 only exception is when U-Boot is loaded (to RAM) by
2328 some other boot loader or by a debugger which
2329 performs these intializations itself.
2332 Building the Software:
2333 ======================
2335 Building U-Boot has been tested in native PPC environments (on a
2336 PowerBook G3 running LinuxPPC 2000) and in cross environments
2337 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2340 If you are not using a native PPC environment, it is assumed that you
2341 have the GNU cross compiling tools available in your path and named
2342 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2343 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2344 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2347 CROSS_COMPILE = ppc_4xx-
2350 U-Boot is intended to be simple to build. After installing the
2351 sources you must configure U-Boot for one specific board type. This
2356 where "NAME_config" is the name of one of the existing
2357 configurations; the following names are supported:
2359 ADCIOP_config FPS860L_config omap730p2_config
2360 ADS860_config GEN860T_config pcu_e_config
2362 AR405_config GENIETV_config PIP405_config
2363 at91rm9200dk_config GTH_config QS823_config
2364 CANBT_config hermes_config QS850_config
2365 cmi_mpc5xx_config hymod_config QS860T_config
2366 cogent_common_config IP860_config RPXlite_config
2367 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2368 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2369 CPCI405_config JSE_config rsdproto_config
2370 CPCIISER4_config LANTEC_config Sandpoint8240_config
2371 csb272_config lwmon_config sbc8260_config
2372 CU824_config MBX860T_config sbc8560_33_config
2373 DUET_ADS_config MBX_config sbc8560_66_config
2374 EBONY_config MPC8260ADS_config SM850_config
2375 ELPT860_config MPC8540ADS_config SPD823TS_config
2376 ESTEEM192E_config MPC8540EVAL_config stxgp3_config
2377 ETX094_config MPC8560ADS_config SXNI855T_config
2378 FADS823_config NETVIA_config TQM823L_config
2379 FADS850SAR_config omap1510inn_config TQM850L_config
2380 FADS860T_config omap1610h2_config TQM855L_config
2381 FPS850L_config omap1610inn_config TQM860L_config
2382 omap5912osk_config walnut_config
2383 omap2420h4_config Yukon8220_config
2386 Note: for some board special configuration names may exist; check if
2387 additional information is available from the board vendor; for
2388 instance, the TQM823L systems are available without (standard)
2389 or with LCD support. You can select such additional "features"
2390 when chosing the configuration, i. e.
2393 - will configure for a plain TQM823L, i. e. no LCD support
2395 make TQM823L_LCD_config
2396 - will configure for a TQM823L with U-Boot console on LCD
2401 Finally, type "make all", and you should get some working U-Boot
2402 images ready for download to / installation on your system:
2404 - "u-boot.bin" is a raw binary image
2405 - "u-boot" is an image in ELF binary format
2406 - "u-boot.srec" is in Motorola S-Record format
2408 By default the build is performed locally and the objects are saved
2409 in the source directory. One of the two methods can be used to change
2410 this behavior and build U-Boot to some external directory:
2412 1. Add O= to the make command line invocations:
2414 make O=/tmp/build distclean
2415 make O=/tmp/build NAME_config
2416 make O=/tmp/build all
2418 2. Set environment variable BUILD_DIR to point to the desired location:
2420 export BUILD_DIR=/tmp/build
2425 Note that the command line "O=" setting overrides the BUILD_DIR environment
2429 Please be aware that the Makefiles assume you are using GNU make, so
2430 for instance on NetBSD you might need to use "gmake" instead of
2434 If the system board that you have is not listed, then you will need
2435 to port U-Boot to your hardware platform. To do this, follow these
2438 1. Add a new configuration option for your board to the toplevel
2439 "Makefile" and to the "MAKEALL" script, using the existing
2440 entries as examples. Note that here and at many other places
2441 boards and other names are listed in alphabetical sort order. Please
2443 2. Create a new directory to hold your board specific code. Add any
2444 files you need. In your board directory, you will need at least
2445 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2446 3. Create a new configuration file "include/configs/<board>.h" for
2448 3. If you're porting U-Boot to a new CPU, then also create a new
2449 directory to hold your CPU specific code. Add any files you need.
2450 4. Run "make <board>_config" with your new name.
2451 5. Type "make", and you should get a working "u-boot.srec" file
2452 to be installed on your target system.
2453 6. Debug and solve any problems that might arise.
2454 [Of course, this last step is much harder than it sounds.]
2457 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2458 ==============================================================
2460 If you have modified U-Boot sources (for instance added a new board
2461 or support for new devices, a new CPU, etc.) you are expected to
2462 provide feedback to the other developers. The feedback normally takes
2463 the form of a "patch", i. e. a context diff against a certain (latest
2464 official or latest in CVS) version of U-Boot sources.
2466 But before you submit such a patch, please verify that your modifi-
2467 cation did not break existing code. At least make sure that *ALL* of
2468 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2469 just run the "MAKEALL" script, which will configure and build U-Boot
2470 for ALL supported system. Be warned, this will take a while. You can
2471 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2472 environment variable to the script, i. e. to use the cross tools from
2473 MontaVista's Hard Hat Linux you can type
2475 CROSS_COMPILE=ppc_8xx- MAKEALL
2477 or to build on a native PowerPC system you can type
2479 CROSS_COMPILE=' ' MAKEALL
2481 When using the MAKEALL script, the default behaviour is to build U-Boot
2482 in the source directory. This location can be changed by setting the
2483 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2484 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2485 <source dir>/LOG directory. This default location can be changed by
2486 setting the MAKEALL_LOGDIR environment variable. For example:
2488 export BUILD_DIR=/tmp/build
2489 export MAKEALL_LOGDIR=/tmp/log
2490 CROSS_COMPILE=ppc_8xx- MAKEALL
2492 With the above settings build objects are saved in the /tmp/build, log
2493 files are saved in the /tmp/log and the source tree remains clean during
2494 the whole build process.
2497 See also "U-Boot Porting Guide" below.
2500 Monitor Commands - Overview:
2501 ============================
2503 go - start application at address 'addr'
2504 run - run commands in an environment variable
2505 bootm - boot application image from memory
2506 bootp - boot image via network using BootP/TFTP protocol
2507 tftpboot- boot image via network using TFTP protocol
2508 and env variables "ipaddr" and "serverip"
2509 (and eventually "gatewayip")
2510 rarpboot- boot image via network using RARP/TFTP protocol
2511 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2512 loads - load S-Record file over serial line
2513 loadb - load binary file over serial line (kermit mode)
2515 mm - memory modify (auto-incrementing)
2516 nm - memory modify (constant address)
2517 mw - memory write (fill)
2519 cmp - memory compare
2520 crc32 - checksum calculation
2521 imd - i2c memory display
2522 imm - i2c memory modify (auto-incrementing)
2523 inm - i2c memory modify (constant address)
2524 imw - i2c memory write (fill)
2525 icrc32 - i2c checksum calculation
2526 iprobe - probe to discover valid I2C chip addresses
2527 iloop - infinite loop on address range
2528 isdram - print SDRAM configuration information
2529 sspi - SPI utility commands
2530 base - print or set address offset
2531 printenv- print environment variables
2532 setenv - set environment variables
2533 saveenv - save environment variables to persistent storage
2534 protect - enable or disable FLASH write protection
2535 erase - erase FLASH memory
2536 flinfo - print FLASH memory information
2537 bdinfo - print Board Info structure
2538 iminfo - print header information for application image
2539 coninfo - print console devices and informations
2540 ide - IDE sub-system
2541 loop - infinite loop on address range
2542 loopw - infinite write loop on address range
2543 mtest - simple RAM test
2544 icache - enable or disable instruction cache
2545 dcache - enable or disable data cache
2546 reset - Perform RESET of the CPU
2547 echo - echo args to console
2548 version - print monitor version
2549 help - print online help
2550 ? - alias for 'help'
2553 Monitor Commands - Detailed Description:
2554 ========================================
2558 For now: just type "help <command>".
2561 Environment Variables:
2562 ======================
2564 U-Boot supports user configuration using Environment Variables which
2565 can be made persistent by saving to Flash memory.
2567 Environment Variables are set using "setenv", printed using
2568 "printenv", and saved to Flash using "saveenv". Using "setenv"
2569 without a value can be used to delete a variable from the
2570 environment. As long as you don't save the environment you are
2571 working with an in-memory copy. In case the Flash area containing the
2572 environment is erased by accident, a default environment is provided.
2574 Some configuration options can be set using Environment Variables:
2576 baudrate - see CONFIG_BAUDRATE
2578 bootdelay - see CONFIG_BOOTDELAY
2580 bootcmd - see CONFIG_BOOTCOMMAND
2582 bootargs - Boot arguments when booting an RTOS image
2584 bootfile - Name of the image to load with TFTP
2586 autoload - if set to "no" (any string beginning with 'n'),
2587 "bootp" will just load perform a lookup of the
2588 configuration from the BOOTP server, but not try to
2589 load any image using TFTP
2591 autostart - if set to "yes", an image loaded using the "bootp",
2592 "rarpboot", "tftpboot" or "diskboot" commands will
2593 be automatically started (by internally calling
2596 If set to "no", a standalone image passed to the
2597 "bootm" command will be copied to the load address
2598 (and eventually uncompressed), but NOT be started.
2599 This can be used to load and uncompress arbitrary
2602 i2cfast - (PPC405GP|PPC405EP only)
2603 if set to 'y' configures Linux I2C driver for fast
2604 mode (400kHZ). This environment variable is used in
2605 initialization code. So, for changes to be effective
2606 it must be saved and board must be reset.
2608 initrd_high - restrict positioning of initrd images:
2609 If this variable is not set, initrd images will be
2610 copied to the highest possible address in RAM; this
2611 is usually what you want since it allows for
2612 maximum initrd size. If for some reason you want to
2613 make sure that the initrd image is loaded below the
2614 CFG_BOOTMAPSZ limit, you can set this environment
2615 variable to a value of "no" or "off" or "0".
2616 Alternatively, you can set it to a maximum upper
2617 address to use (U-Boot will still check that it
2618 does not overwrite the U-Boot stack and data).
2620 For instance, when you have a system with 16 MB
2621 RAM, and want to reserve 4 MB from use by Linux,
2622 you can do this by adding "mem=12M" to the value of
2623 the "bootargs" variable. However, now you must make
2624 sure that the initrd image is placed in the first
2625 12 MB as well - this can be done with
2627 setenv initrd_high 00c00000
2629 If you set initrd_high to 0xFFFFFFFF, this is an
2630 indication to U-Boot that all addresses are legal
2631 for the Linux kernel, including addresses in flash
2632 memory. In this case U-Boot will NOT COPY the
2633 ramdisk at all. This may be useful to reduce the
2634 boot time on your system, but requires that this
2635 feature is supported by your Linux kernel.
2637 ipaddr - IP address; needed for tftpboot command
2639 loadaddr - Default load address for commands like "bootp",
2640 "rarpboot", "tftpboot", "loadb" or "diskboot"
2642 loads_echo - see CONFIG_LOADS_ECHO
2644 serverip - TFTP server IP address; needed for tftpboot command
2646 bootretry - see CONFIG_BOOT_RETRY_TIME
2648 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2650 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2652 ethprime - When CONFIG_NET_MULTI is enabled controls which
2653 interface is used first.
2655 ethact - When CONFIG_NET_MULTI is enabled controls which
2656 interface is currently active. For example you
2657 can do the following
2659 => setenv ethact FEC ETHERNET
2660 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2661 => setenv ethact SCC ETHERNET
2662 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2664 netretry - When set to "no" each network operation will
2665 either succeed or fail without retrying.
2666 When set to "once" the network operation will
2667 fail when all the available network interfaces
2668 are tried once without success.
2669 Useful on scripts which control the retry operation
2672 tftpsrcport - If this is set, the value is used for TFTP's
2675 tftpdstport - If this is set, the value is used for TFTP's UDP
2676 destination port instead of the Well Know Port 69.
2678 vlan - When set to a value < 4095 the traffic over
2679 ethernet is encapsulated/received over 802.1q
2682 The following environment variables may be used and automatically
2683 updated by the network boot commands ("bootp" and "rarpboot"),
2684 depending the information provided by your boot server:
2686 bootfile - see above
2687 dnsip - IP address of your Domain Name Server
2688 dnsip2 - IP address of your secondary Domain Name Server
2689 gatewayip - IP address of the Gateway (Router) to use
2690 hostname - Target hostname
2692 netmask - Subnet Mask
2693 rootpath - Pathname of the root filesystem on the NFS server
2694 serverip - see above
2697 There are two special Environment Variables:
2699 serial# - contains hardware identification information such
2700 as type string and/or serial number
2701 ethaddr - Ethernet address
2703 These variables can be set only once (usually during manufacturing of
2704 the board). U-Boot refuses to delete or overwrite these variables
2705 once they have been set once.
2708 Further special Environment Variables:
2710 ver - Contains the U-Boot version string as printed
2711 with the "version" command. This variable is
2712 readonly (see CONFIG_VERSION_VARIABLE).
2715 Please note that changes to some configuration parameters may take
2716 only effect after the next boot (yes, that's just like Windoze :-).
2719 Command Line Parsing:
2720 =====================
2722 There are two different command line parsers available with U-Boot:
2723 the old "simple" one, and the much more powerful "hush" shell:
2725 Old, simple command line parser:
2726 --------------------------------
2728 - supports environment variables (through setenv / saveenv commands)
2729 - several commands on one line, separated by ';'
2730 - variable substitution using "... ${name} ..." syntax
2731 - special characters ('$', ';') can be escaped by prefixing with '\',
2733 setenv bootcmd bootm \${address}
2734 - You can also escape text by enclosing in single apostrophes, for example:
2735 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2740 - similar to Bourne shell, with control structures like
2741 if...then...else...fi, for...do...done; while...do...done,
2742 until...do...done, ...
2743 - supports environment ("global") variables (through setenv / saveenv
2744 commands) and local shell variables (through standard shell syntax
2745 "name=value"); only environment variables can be used with "run"
2751 (1) If a command line (or an environment variable executed by a "run"
2752 command) contains several commands separated by semicolon, and
2753 one of these commands fails, then the remaining commands will be
2756 (2) If you execute several variables with one call to run (i. e.
2757 calling run with a list af variables as arguments), any failing
2758 command will cause "run" to terminate, i. e. the remaining
2759 variables are not executed.
2761 Note for Redundant Ethernet Interfaces:
2762 =======================================
2764 Some boards come with redundant ethernet interfaces; U-Boot supports
2765 such configurations and is capable of automatic selection of a
2766 "working" interface when needed. MAC assignment works as follows:
2768 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2769 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2770 "eth1addr" (=>eth1), "eth2addr", ...
2772 If the network interface stores some valid MAC address (for instance
2773 in SROM), this is used as default address if there is NO correspon-
2774 ding setting in the environment; if the corresponding environment
2775 variable is set, this overrides the settings in the card; that means:
2777 o If the SROM has a valid MAC address, and there is no address in the
2778 environment, the SROM's address is used.
2780 o If there is no valid address in the SROM, and a definition in the
2781 environment exists, then the value from the environment variable is
2784 o If both the SROM and the environment contain a MAC address, and
2785 both addresses are the same, this MAC address is used.
2787 o If both the SROM and the environment contain a MAC address, and the
2788 addresses differ, the value from the environment is used and a
2791 o If neither SROM nor the environment contain a MAC address, an error
2798 The "boot" commands of this monitor operate on "image" files which
2799 can be basicly anything, preceeded by a special header; see the
2800 definitions in include/image.h for details; basicly, the header
2801 defines the following image properties:
2803 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2804 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2805 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2806 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2807 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2808 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2809 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2810 * Compression Type (uncompressed, gzip, bzip2)
2816 The header is marked by a special Magic Number, and both the header
2817 and the data portions of the image are secured against corruption by
2824 Although U-Boot should support any OS or standalone application
2825 easily, the main focus has always been on Linux during the design of
2828 U-Boot includes many features that so far have been part of some
2829 special "boot loader" code within the Linux kernel. Also, any
2830 "initrd" images to be used are no longer part of one big Linux image;
2831 instead, kernel and "initrd" are separate images. This implementation
2832 serves several purposes:
2834 - the same features can be used for other OS or standalone
2835 applications (for instance: using compressed images to reduce the
2836 Flash memory footprint)
2838 - it becomes much easier to port new Linux kernel versions because
2839 lots of low-level, hardware dependent stuff are done by U-Boot
2841 - the same Linux kernel image can now be used with different "initrd"
2842 images; of course this also means that different kernel images can
2843 be run with the same "initrd". This makes testing easier (you don't
2844 have to build a new "zImage.initrd" Linux image when you just
2845 change a file in your "initrd"). Also, a field-upgrade of the
2846 software is easier now.
2852 Porting Linux to U-Boot based systems:
2853 ---------------------------------------
2855 U-Boot cannot save you from doing all the necessary modifications to
2856 configure the Linux device drivers for use with your target hardware
2857 (no, we don't intend to provide a full virtual machine interface to
2860 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2862 Just make sure your machine specific header file (for instance
2863 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2864 Information structure as we define in include/u-boot.h, and make
2865 sure that your definition of IMAP_ADDR uses the same value as your
2866 U-Boot configuration in CFG_IMMR.
2869 Configuring the Linux kernel:
2870 -----------------------------
2872 No specific requirements for U-Boot. Make sure you have some root
2873 device (initial ramdisk, NFS) for your target system.
2876 Building a Linux Image:
2877 -----------------------
2879 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2880 not used. If you use recent kernel source, a new build target
2881 "uImage" will exist which automatically builds an image usable by
2882 U-Boot. Most older kernels also have support for a "pImage" target,
2883 which was introduced for our predecessor project PPCBoot and uses a
2884 100% compatible format.
2893 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2894 encapsulate a compressed Linux kernel image with header information,
2895 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2897 * build a standard "vmlinux" kernel image (in ELF binary format):
2899 * convert the kernel into a raw binary image:
2901 ${CROSS_COMPILE}-objcopy -O binary \
2902 -R .note -R .comment \
2903 -S vmlinux linux.bin
2905 * compress the binary image:
2909 * package compressed binary image for U-Boot:
2911 mkimage -A ppc -O linux -T kernel -C gzip \
2912 -a 0 -e 0 -n "Linux Kernel Image" \
2913 -d linux.bin.gz uImage
2916 The "mkimage" tool can also be used to create ramdisk images for use
2917 with U-Boot, either separated from the Linux kernel image, or
2918 combined into one file. "mkimage" encapsulates the images with a 64
2919 byte header containing information about target architecture,
2920 operating system, image type, compression method, entry points, time
2921 stamp, CRC32 checksums, etc.
2923 "mkimage" can be called in two ways: to verify existing images and
2924 print the header information, or to build new images.
2926 In the first form (with "-l" option) mkimage lists the information
2927 contained in the header of an existing U-Boot image; this includes
2928 checksum verification:
2930 tools/mkimage -l image
2931 -l ==> list image header information
2933 The second form (with "-d" option) is used to build a U-Boot image
2934 from a "data file" which is used as image payload:
2936 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2937 -n name -d data_file image
2938 -A ==> set architecture to 'arch'
2939 -O ==> set operating system to 'os'
2940 -T ==> set image type to 'type'
2941 -C ==> set compression type 'comp'
2942 -a ==> set load address to 'addr' (hex)
2943 -e ==> set entry point to 'ep' (hex)
2944 -n ==> set image name to 'name'
2945 -d ==> use image data from 'datafile'
2947 Right now, all Linux kernels for PowerPC systems use the same load
2948 address (0x00000000), but the entry point address depends on the
2951 - 2.2.x kernels have the entry point at 0x0000000C,
2952 - 2.3.x and later kernels have the entry point at 0x00000000.
2954 So a typical call to build a U-Boot image would read:
2956 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2957 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2958 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2959 > examples/uImage.TQM850L
2960 Image Name: 2.4.4 kernel for TQM850L
2961 Created: Wed Jul 19 02:34:59 2000
2962 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2963 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2964 Load Address: 0x00000000
2965 Entry Point: 0x00000000
2967 To verify the contents of the image (or check for corruption):
2969 -> tools/mkimage -l examples/uImage.TQM850L
2970 Image Name: 2.4.4 kernel for TQM850L
2971 Created: Wed Jul 19 02:34:59 2000
2972 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2973 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2974 Load Address: 0x00000000
2975 Entry Point: 0x00000000
2977 NOTE: for embedded systems where boot time is critical you can trade
2978 speed for memory and install an UNCOMPRESSED image instead: this
2979 needs more space in Flash, but boots much faster since it does not
2980 need to be uncompressed:
2982 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2983 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2984 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2985 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2986 > examples/uImage.TQM850L-uncompressed
2987 Image Name: 2.4.4 kernel for TQM850L
2988 Created: Wed Jul 19 02:34:59 2000
2989 Image Type: PowerPC Linux Kernel Image (uncompressed)
2990 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2991 Load Address: 0x00000000
2992 Entry Point: 0x00000000
2995 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2996 when your kernel is intended to use an initial ramdisk:
2998 -> tools/mkimage -n 'Simple Ramdisk Image' \
2999 > -A ppc -O linux -T ramdisk -C gzip \
3000 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3001 Image Name: Simple Ramdisk Image
3002 Created: Wed Jan 12 14:01:50 2000
3003 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3004 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3005 Load Address: 0x00000000
3006 Entry Point: 0x00000000
3009 Installing a Linux Image:
3010 -------------------------
3012 To downloading a U-Boot image over the serial (console) interface,
3013 you must convert the image to S-Record format:
3015 objcopy -I binary -O srec examples/image examples/image.srec
3017 The 'objcopy' does not understand the information in the U-Boot
3018 image header, so the resulting S-Record file will be relative to
3019 address 0x00000000. To load it to a given address, you need to
3020 specify the target address as 'offset' parameter with the 'loads'
3023 Example: install the image to address 0x40100000 (which on the
3024 TQM8xxL is in the first Flash bank):
3026 => erase 40100000 401FFFFF
3032 ## Ready for S-Record download ...
3033 ~>examples/image.srec
3034 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3036 15989 15990 15991 15992
3037 [file transfer complete]
3039 ## Start Addr = 0x00000000
3042 You can check the success of the download using the 'iminfo' command;
3043 this includes a checksum verification so you can be sure no data
3044 corruption happened:
3048 ## Checking Image at 40100000 ...
3049 Image Name: 2.2.13 for initrd on TQM850L
3050 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3051 Data Size: 335725 Bytes = 327 kB = 0 MB
3052 Load Address: 00000000
3053 Entry Point: 0000000c
3054 Verifying Checksum ... OK
3060 The "bootm" command is used to boot an application that is stored in
3061 memory (RAM or Flash). In case of a Linux kernel image, the contents
3062 of the "bootargs" environment variable is passed to the kernel as
3063 parameters. You can check and modify this variable using the
3064 "printenv" and "setenv" commands:
3067 => printenv bootargs
3068 bootargs=root=/dev/ram
3070 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3072 => printenv bootargs
3073 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3076 ## Booting Linux kernel at 40020000 ...
3077 Image Name: 2.2.13 for NFS on TQM850L
3078 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3079 Data Size: 381681 Bytes = 372 kB = 0 MB
3080 Load Address: 00000000
3081 Entry Point: 0000000c
3082 Verifying Checksum ... OK
3083 Uncompressing Kernel Image ... OK
3084 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
3085 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3086 time_init: decrementer frequency = 187500000/60
3087 Calibrating delay loop... 49.77 BogoMIPS
3088 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3091 If you want to boot a Linux kernel with initial ram disk, you pass
3092 the memory addresses of both the kernel and the initrd image (PPBCOOT
3093 format!) to the "bootm" command:
3095 => imi 40100000 40200000
3097 ## Checking Image at 40100000 ...
3098 Image Name: 2.2.13 for initrd on TQM850L
3099 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3100 Data Size: 335725 Bytes = 327 kB = 0 MB
3101 Load Address: 00000000
3102 Entry Point: 0000000c
3103 Verifying Checksum ... OK
3105 ## Checking Image at 40200000 ...
3106 Image Name: Simple Ramdisk Image
3107 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3108 Data Size: 566530 Bytes = 553 kB = 0 MB
3109 Load Address: 00000000
3110 Entry Point: 00000000
3111 Verifying Checksum ... OK
3113 => bootm 40100000 40200000
3114 ## Booting Linux kernel at 40100000 ...
3115 Image Name: 2.2.13 for initrd on TQM850L
3116 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3117 Data Size: 335725 Bytes = 327 kB = 0 MB
3118 Load Address: 00000000
3119 Entry Point: 0000000c
3120 Verifying Checksum ... OK
3121 Uncompressing Kernel Image ... OK
3122 ## Loading RAMDisk Image at 40200000 ...
3123 Image Name: Simple Ramdisk Image
3124 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3125 Data Size: 566530 Bytes = 553 kB = 0 MB
3126 Load Address: 00000000
3127 Entry Point: 00000000
3128 Verifying Checksum ... OK
3129 Loading Ramdisk ... OK
3130 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
3131 Boot arguments: root=/dev/ram
3132 time_init: decrementer frequency = 187500000/60
3133 Calibrating delay loop... 49.77 BogoMIPS
3135 RAMDISK: Compressed image found at block 0
3136 VFS: Mounted root (ext2 filesystem).
3140 Boot Linux and pass a flat device tree:
3143 First, U-Boot must be compiled with the appropriate defines. See the section
3144 titled "Linux Kernel Interface" above for a more in depth explanation. The
3145 following is an example of how to start a kernel and pass an updated
3151 oft=oftrees/mpc8540ads.dtb
3152 => tftp $oftaddr $oft
3153 Speed: 1000, full duplex
3155 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3156 Filename 'oftrees/mpc8540ads.dtb'.
3157 Load address: 0x300000
3160 Bytes transferred = 4106 (100a hex)
3161 => tftp $loadaddr $bootfile
3162 Speed: 1000, full duplex
3164 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3166 Load address: 0x200000
3167 Loading:############
3169 Bytes transferred = 1029407 (fb51f hex)
3174 => bootm $loadaddr - $oftaddr
3175 ## Booting image at 00200000 ...
3176 Image Name: Linux-2.6.17-dirty
3177 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3178 Data Size: 1029343 Bytes = 1005.2 kB
3179 Load Address: 00000000
3180 Entry Point: 00000000
3181 Verifying Checksum ... OK
3182 Uncompressing Kernel Image ... OK
3183 Booting using flat device tree at 0x300000
3184 Using MPC85xx ADS machine description
3185 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3189 More About U-Boot Image Types:
3190 ------------------------------
3192 U-Boot supports the following image types:
3194 "Standalone Programs" are directly runnable in the environment
3195 provided by U-Boot; it is expected that (if they behave
3196 well) you can continue to work in U-Boot after return from
3197 the Standalone Program.
3198 "OS Kernel Images" are usually images of some Embedded OS which
3199 will take over control completely. Usually these programs
3200 will install their own set of exception handlers, device
3201 drivers, set up the MMU, etc. - this means, that you cannot
3202 expect to re-enter U-Boot except by resetting the CPU.
3203 "RAMDisk Images" are more or less just data blocks, and their
3204 parameters (address, size) are passed to an OS kernel that is
3206 "Multi-File Images" contain several images, typically an OS
3207 (Linux) kernel image and one or more data images like
3208 RAMDisks. This construct is useful for instance when you want
3209 to boot over the network using BOOTP etc., where the boot
3210 server provides just a single image file, but you want to get
3211 for instance an OS kernel and a RAMDisk image.
3213 "Multi-File Images" start with a list of image sizes, each
3214 image size (in bytes) specified by an "uint32_t" in network
3215 byte order. This list is terminated by an "(uint32_t)0".
3216 Immediately after the terminating 0 follow the images, one by
3217 one, all aligned on "uint32_t" boundaries (size rounded up to
3218 a multiple of 4 bytes).
3220 "Firmware Images" are binary images containing firmware (like
3221 U-Boot or FPGA images) which usually will be programmed to
3224 "Script files" are command sequences that will be executed by
3225 U-Boot's command interpreter; this feature is especially
3226 useful when you configure U-Boot to use a real shell (hush)
3227 as command interpreter.
3233 One of the features of U-Boot is that you can dynamically load and
3234 run "standalone" applications, which can use some resources of
3235 U-Boot like console I/O functions or interrupt services.
3237 Two simple examples are included with the sources:
3242 'examples/hello_world.c' contains a small "Hello World" Demo
3243 application; it is automatically compiled when you build U-Boot.
3244 It's configured to run at address 0x00040004, so you can play with it
3248 ## Ready for S-Record download ...
3249 ~>examples/hello_world.srec
3250 1 2 3 4 5 6 7 8 9 10 11 ...
3251 [file transfer complete]
3253 ## Start Addr = 0x00040004
3255 => go 40004 Hello World! This is a test.
3256 ## Starting application at 0x00040004 ...
3267 Hit any key to exit ...
3269 ## Application terminated, rc = 0x0
3271 Another example, which demonstrates how to register a CPM interrupt
3272 handler with the U-Boot code, can be found in 'examples/timer.c'.
3273 Here, a CPM timer is set up to generate an interrupt every second.
3274 The interrupt service routine is trivial, just printing a '.'
3275 character, but this is just a demo program. The application can be
3276 controlled by the following keys:
3278 ? - print current values og the CPM Timer registers
3279 b - enable interrupts and start timer
3280 e - stop timer and disable interrupts
3281 q - quit application
3284 ## Ready for S-Record download ...
3285 ~>examples/timer.srec
3286 1 2 3 4 5 6 7 8 9 10 11 ...
3287 [file transfer complete]
3289 ## Start Addr = 0x00040004
3292 ## Starting application at 0x00040004 ...
3295 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3298 [q, b, e, ?] Set interval 1000000 us
3301 [q, b, e, ?] ........
3302 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3305 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3308 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3311 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3313 [q, b, e, ?] ...Stopping timer
3315 [q, b, e, ?] ## Application terminated, rc = 0x0
3321 Over time, many people have reported problems when trying to use the
3322 "minicom" terminal emulation program for serial download. I (wd)
3323 consider minicom to be broken, and recommend not to use it. Under
3324 Unix, I recommend to use C-Kermit for general purpose use (and
3325 especially for kermit binary protocol download ("loadb" command), and
3326 use "cu" for S-Record download ("loads" command).
3328 Nevertheless, if you absolutely want to use it try adding this
3329 configuration to your "File transfer protocols" section:
3331 Name Program Name U/D FullScr IO-Red. Multi
3332 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3333 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3339 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3340 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3342 Building requires a cross environment; it is known to work on
3343 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3344 need gmake since the Makefiles are not compatible with BSD make).
3345 Note that the cross-powerpc package does not install include files;
3346 attempting to build U-Boot will fail because <machine/ansi.h> is
3347 missing. This file has to be installed and patched manually:
3349 # cd /usr/pkg/cross/powerpc-netbsd/include
3351 # ln -s powerpc machine
3352 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3353 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3355 Native builds *don't* work due to incompatibilities between native
3356 and U-Boot include files.
3358 Booting assumes that (the first part of) the image booted is a
3359 stage-2 loader which in turn loads and then invokes the kernel
3360 proper. Loader sources will eventually appear in the NetBSD source
3361 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3362 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3365 Implementation Internals:
3366 =========================
3368 The following is not intended to be a complete description of every
3369 implementation detail. However, it should help to understand the
3370 inner workings of U-Boot and make it easier to port it to custom
3374 Initial Stack, Global Data:
3375 ---------------------------
3377 The implementation of U-Boot is complicated by the fact that U-Boot
3378 starts running out of ROM (flash memory), usually without access to
3379 system RAM (because the memory controller is not initialized yet).
3380 This means that we don't have writable Data or BSS segments, and BSS
3381 is not initialized as zero. To be able to get a C environment working
3382 at all, we have to allocate at least a minimal stack. Implementation
3383 options for this are defined and restricted by the CPU used: Some CPU
3384 models provide on-chip memory (like the IMMR area on MPC8xx and
3385 MPC826x processors), on others (parts of) the data cache can be
3386 locked as (mis-) used as memory, etc.
3388 Chris Hallinan posted a good summary of these issues to the
3389 u-boot-users mailing list:
3391 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3392 From: "Chris Hallinan" <clh@net1plus.com>
3393 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3396 Correct me if I'm wrong, folks, but the way I understand it
3397 is this: Using DCACHE as initial RAM for Stack, etc, does not
3398 require any physical RAM backing up the cache. The cleverness
3399 is that the cache is being used as a temporary supply of
3400 necessary storage before the SDRAM controller is setup. It's
3401 beyond the scope of this list to expain the details, but you
3402 can see how this works by studying the cache architecture and
3403 operation in the architecture and processor-specific manuals.
3405 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3406 is another option for the system designer to use as an
3407 initial stack/ram area prior to SDRAM being available. Either
3408 option should work for you. Using CS 4 should be fine if your
3409 board designers haven't used it for something that would
3410 cause you grief during the initial boot! It is frequently not
3413 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3414 with your processor/board/system design. The default value
3415 you will find in any recent u-boot distribution in
3416 walnut.h should work for you. I'd set it to a value larger
3417 than your SDRAM module. If you have a 64MB SDRAM module, set
3418 it above 400_0000. Just make sure your board has no resources
3419 that are supposed to respond to that address! That code in
3420 start.S has been around a while and should work as is when
3421 you get the config right.
3426 It is essential to remember this, since it has some impact on the C
3427 code for the initialization procedures:
3429 * Initialized global data (data segment) is read-only. Do not attempt
3432 * Do not use any unitialized global data (or implicitely initialized
3433 as zero data - BSS segment) at all - this is undefined, initiali-
3434 zation is performed later (when relocating to RAM).
3436 * Stack space is very limited. Avoid big data buffers or things like
3439 Having only the stack as writable memory limits means we cannot use
3440 normal global data to share information beween the code. But it
3441 turned out that the implementation of U-Boot can be greatly
3442 simplified by making a global data structure (gd_t) available to all
3443 functions. We could pass a pointer to this data as argument to _all_
3444 functions, but this would bloat the code. Instead we use a feature of
3445 the GCC compiler (Global Register Variables) to share the data: we
3446 place a pointer (gd) to the global data into a register which we
3447 reserve for this purpose.
3449 When choosing a register for such a purpose we are restricted by the
3450 relevant (E)ABI specifications for the current architecture, and by
3451 GCC's implementation.
3453 For PowerPC, the following registers have specific use:
3456 R3-R4: parameter passing and return values
3457 R5-R10: parameter passing
3458 R13: small data area pointer
3462 (U-Boot also uses R14 as internal GOT pointer.)
3464 ==> U-Boot will use R29 to hold a pointer to the global data
3466 Note: on PPC, we could use a static initializer (since the
3467 address of the global data structure is known at compile time),
3468 but it turned out that reserving a register results in somewhat
3469 smaller code - although the code savings are not that big (on
3470 average for all boards 752 bytes for the whole U-Boot image,
3471 624 text + 127 data).
3473 On ARM, the following registers are used:
3475 R0: function argument word/integer result
3476 R1-R3: function argument word
3478 R10: stack limit (used only if stack checking if enabled)
3479 R11: argument (frame) pointer
3480 R12: temporary workspace
3483 R15: program counter
3485 ==> U-Boot will use R8 to hold a pointer to the global data
3487 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3488 or current versions of GCC may "optimize" the code too much.
3493 U-Boot runs in system state and uses physical addresses, i.e. the
3494 MMU is not used either for address mapping nor for memory protection.
3496 The available memory is mapped to fixed addresses using the memory
3497 controller. In this process, a contiguous block is formed for each
3498 memory type (Flash, SDRAM, SRAM), even when it consists of several
3499 physical memory banks.
3501 U-Boot is installed in the first 128 kB of the first Flash bank (on
3502 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3503 booting and sizing and initializing DRAM, the code relocates itself
3504 to the upper end of DRAM. Immediately below the U-Boot code some
3505 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3506 configuration setting]. Below that, a structure with global Board
3507 Info data is placed, followed by the stack (growing downward).
3509 Additionally, some exception handler code is copied to the low 8 kB
3510 of DRAM (0x00000000 ... 0x00001FFF).
3512 So a typical memory configuration with 16 MB of DRAM could look like
3515 0x0000 0000 Exception Vector code
3518 0x0000 2000 Free for Application Use
3524 0x00FB FF20 Monitor Stack (Growing downward)
3525 0x00FB FFAC Board Info Data and permanent copy of global data
3526 0x00FC 0000 Malloc Arena
3529 0x00FE 0000 RAM Copy of Monitor Code
3530 ... eventually: LCD or video framebuffer
3531 ... eventually: pRAM (Protected RAM - unchanged by reset)
3532 0x00FF FFFF [End of RAM]
3535 System Initialization:
3536 ----------------------
3538 In the reset configuration, U-Boot starts at the reset entry point
3539 (on most PowerPC systens at address 0x00000100). Because of the reset
3540 configuration for CS0# this is a mirror of the onboard Flash memory.
3541 To be able to re-map memory U-Boot then jumps to its link address.
3542 To be able to implement the initialization code in C, a (small!)
3543 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3544 which provide such a feature like MPC8xx or MPC8260), or in a locked
3545 part of the data cache. After that, U-Boot initializes the CPU core,
3546 the caches and the SIU.
3548 Next, all (potentially) available memory banks are mapped using a
3549 preliminary mapping. For example, we put them on 512 MB boundaries
3550 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3551 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3552 programmed for SDRAM access. Using the temporary configuration, a
3553 simple memory test is run that determines the size of the SDRAM
3556 When there is more than one SDRAM bank, and the banks are of
3557 different size, the largest is mapped first. For equal size, the first
3558 bank (CS2#) is mapped first. The first mapping is always for address
3559 0x00000000, with any additional banks following immediately to create
3560 contiguous memory starting from 0.
3562 Then, the monitor installs itself at the upper end of the SDRAM area
3563 and allocates memory for use by malloc() and for the global Board
3564 Info data; also, the exception vector code is copied to the low RAM
3565 pages, and the final stack is set up.
3567 Only after this relocation will you have a "normal" C environment;
3568 until that you are restricted in several ways, mostly because you are
3569 running from ROM, and because the code will have to be relocated to a
3573 U-Boot Porting Guide:
3574 ----------------------
3576 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3580 int main (int argc, char *argv[])
3582 sighandler_t no_more_time;
3584 signal (SIGALRM, no_more_time);
3585 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3587 if (available_money > available_manpower) {
3588 pay consultant to port U-Boot;
3592 Download latest U-Boot source;
3594 Subscribe to u-boot-users mailing list;
3597 email ("Hi, I am new to U-Boot, how do I get started?");
3601 Read the README file in the top level directory;
3602 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3603 Read the source, Luke;
3606 if (available_money > toLocalCurrency ($2500)) {
3609 Add a lot of aggravation and time;
3612 Create your own board support subdirectory;
3614 Create your own board config file;
3618 Add / modify source code;
3622 email ("Hi, I am having problems...");
3624 Send patch file to Wolfgang;
3629 void no_more_time (int sig)
3638 All contributions to U-Boot should conform to the Linux kernel
3639 coding style; see the file "Documentation/CodingStyle" and the script
3640 "scripts/Lindent" in your Linux kernel source directory. In sources
3641 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3642 spaces before parameters to function calls) is actually used.
3644 Source files originating from a different project (for example the
3645 MTD subsystem) are generally exempt from these guidelines and are not
3646 reformated to ease subsequent migration to newer versions of those
3649 Please note that U-Boot is implemented in C (and to some small parts in
3650 Assembler); no C++ is used, so please do not use C++ style comments (//)
3653 Please also stick to the following formatting rules:
3654 - remove any trailing white space
3655 - use TAB characters for indentation, not spaces
3656 - make sure NOT to use DOS '\r\n' line feeds
3657 - do not add more than 2 empty lines to source files
3658 - do not add trailing empty lines to source files
3660 Submissions which do not conform to the standards may be returned
3661 with a request to reformat the changes.
3667 Since the number of patches for U-Boot is growing, we need to
3668 establish some rules. Submissions which do not conform to these rules
3669 may be rejected, even when they contain important and valuable stuff.
3671 Patches shall be sent to the u-boot-users mailing list.
3673 When you send a patch, please include the following information with
3676 * For bug fixes: a description of the bug and how your patch fixes
3677 this bug. Please try to include a way of demonstrating that the
3678 patch actually fixes something.
3680 * For new features: a description of the feature and your
3683 * A CHANGELOG entry as plaintext (separate from the patch)
3685 * For major contributions, your entry to the CREDITS file
3687 * When you add support for a new board, don't forget to add this
3688 board to the MAKEALL script, too.
3690 * If your patch adds new configuration options, don't forget to
3691 document these in the README file.
3693 * The patch itself. If you are accessing the CVS repository use "cvs
3694 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3695 version of diff does not support these options, then get the latest
3696 version of GNU diff.
3698 The current directory when running this command shall be the top
3699 level directory of the U-Boot source tree, or it's parent directory
3700 (i. e. please make sure that your patch includes sufficient
3701 directory information for the affected files).
3703 We accept patches as plain text, MIME attachments or as uuencoded
3706 * If one logical set of modifications affects or creates several
3707 files, all these changes shall be submitted in a SINGLE patch file.
3709 * Changesets that contain different, unrelated modifications shall be
3710 submitted as SEPARATE patches, one patch per changeset.
3715 * Before sending the patch, run the MAKEALL script on your patched
3716 source tree and make sure that no errors or warnings are reported
3717 for any of the boards.
3719 * Keep your modifications to the necessary minimum: A patch
3720 containing several unrelated changes or arbitrary reformats will be
3721 returned with a request to re-formatting / split it.
3723 * If you modify existing code, make sure that your new code does not
3724 add to the memory footprint of the code ;-) Small is beautiful!
3725 When adding new features, these should compile conditionally only
3726 (using #ifdef), and the resulting code with the new feature
3727 disabled must not need more memory than the old code without your
3730 * Remember that there is a size limit of 40 kB per message on the
3731 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob