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 If defined, then this indicates the I2C bus number for the RTC.
1353 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1357 If defined, then this indicates the I2C bus number for the DTT.
1358 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1362 Define this option if you want to use Freescale's I2C driver in
1366 - SPI Support: CONFIG_SPI
1368 Enables SPI driver (so far only tested with
1369 SPI EEPROM, also an instance works with Crystal A/D and
1370 D/As on the SACSng board)
1374 Enables extended (16-bit) SPI EEPROM addressing.
1375 (symmetrical to CONFIG_I2C_X)
1379 Enables a software (bit-bang) SPI driver rather than
1380 using hardware support. This is a general purpose
1381 driver that only requires three general I/O port pins
1382 (two outputs, one input) to function. If this is
1383 defined, the board configuration must define several
1384 SPI configuration items (port pins to use, etc). For
1385 an example, see include/configs/sacsng.h.
1387 - FPGA Support: CONFIG_FPGA_COUNT
1389 Specify the number of FPGA devices to support.
1393 Used to specify the types of FPGA devices. For example,
1394 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1396 CFG_FPGA_PROG_FEEDBACK
1398 Enable printing of hash marks during FPGA configuration.
1402 Enable checks on FPGA configuration interface busy
1403 status by the configuration function. This option
1404 will require a board or device specific function to
1409 If defined, a function that provides delays in the FPGA
1410 configuration driver.
1412 CFG_FPGA_CHECK_CTRLC
1413 Allow Control-C to interrupt FPGA configuration
1415 CFG_FPGA_CHECK_ERROR
1417 Check for configuration errors during FPGA bitfile
1418 loading. For example, abort during Virtex II
1419 configuration if the INIT_B line goes low (which
1420 indicated a CRC error).
1424 Maximum time to wait for the INIT_B line to deassert
1425 after PROB_B has been deasserted during a Virtex II
1426 FPGA configuration sequence. The default time is 500
1431 Maximum time to wait for BUSY to deassert during
1432 Virtex II FPGA configuration. The default is 5 mS.
1434 CFG_FPGA_WAIT_CONFIG
1436 Time to wait after FPGA configuration. The default is
1439 - Configuration Management:
1442 If defined, this string will be added to the U-Boot
1443 version information (U_BOOT_VERSION)
1445 - Vendor Parameter Protection:
1447 U-Boot considers the values of the environment
1448 variables "serial#" (Board Serial Number) and
1449 "ethaddr" (Ethernet Address) to be parameters that
1450 are set once by the board vendor / manufacturer, and
1451 protects these variables from casual modification by
1452 the user. Once set, these variables are read-only,
1453 and write or delete attempts are rejected. You can
1454 change this behviour:
1456 If CONFIG_ENV_OVERWRITE is #defined in your config
1457 file, the write protection for vendor parameters is
1458 completely disabled. Anybody can change or delete
1461 Alternatively, if you #define _both_ CONFIG_ETHADDR
1462 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1463 ethernet address is installed in the environment,
1464 which can be changed exactly ONCE by the user. [The
1465 serial# is unaffected by this, i. e. it remains
1471 Define this variable to enable the reservation of
1472 "protected RAM", i. e. RAM which is not overwritten
1473 by U-Boot. Define CONFIG_PRAM to hold the number of
1474 kB you want to reserve for pRAM. You can overwrite
1475 this default value by defining an environment
1476 variable "pram" to the number of kB you want to
1477 reserve. Note that the board info structure will
1478 still show the full amount of RAM. If pRAM is
1479 reserved, a new environment variable "mem" will
1480 automatically be defined to hold the amount of
1481 remaining RAM in a form that can be passed as boot
1482 argument to Linux, for instance like that:
1484 setenv bootargs ... mem=\${mem}
1487 This way you can tell Linux not to use this memory,
1488 either, which results in a memory region that will
1489 not be affected by reboots.
1491 *WARNING* If your board configuration uses automatic
1492 detection of the RAM size, you must make sure that
1493 this memory test is non-destructive. So far, the
1494 following board configurations are known to be
1497 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1498 HERMES, IP860, RPXlite, LWMON, LANTEC,
1499 PCU_E, FLAGADM, TQM8260
1504 Define this variable to stop the system in case of a
1505 fatal error, so that you have to reset it manually.
1506 This is probably NOT a good idea for an embedded
1507 system where you want to system to reboot
1508 automatically as fast as possible, but it may be
1509 useful during development since you can try to debug
1510 the conditions that lead to the situation.
1512 CONFIG_NET_RETRY_COUNT
1514 This variable defines the number of retries for
1515 network operations like ARP, RARP, TFTP, or BOOTP
1516 before giving up the operation. If not defined, a
1517 default value of 5 is used.
1519 - Command Interpreter:
1520 CONFIG_AUTO_COMPLETE
1522 Enable auto completion of commands using TAB.
1524 Note that this feature has NOT been implemented yet
1525 for the "hush" shell.
1530 Define this variable to enable the "hush" shell (from
1531 Busybox) as command line interpreter, thus enabling
1532 powerful command line syntax like
1533 if...then...else...fi conditionals or `&&' and '||'
1534 constructs ("shell scripts").
1536 If undefined, you get the old, much simpler behaviour
1537 with a somewhat smaller memory footprint.
1542 This defines the secondary prompt string, which is
1543 printed when the command interpreter needs more input
1544 to complete a command. Usually "> ".
1548 In the current implementation, the local variables
1549 space and global environment variables space are
1550 separated. Local variables are those you define by
1551 simply typing `name=value'. To access a local
1552 variable later on, you have write `$name' or
1553 `${name}'; to execute the contents of a variable
1554 directly type `$name' at the command prompt.
1556 Global environment variables are those you use
1557 setenv/printenv to work with. To run a command stored
1558 in such a variable, you need to use the run command,
1559 and you must not use the '$' sign to access them.
1561 To store commands and special characters in a
1562 variable, please use double quotation marks
1563 surrounding the whole text of the variable, instead
1564 of the backslashes before semicolons and special
1567 - Commandline Editing and History:
1568 CONFIG_CMDLINE_EDITING
1570 Enable editiong and History functions for interactive
1571 commandline input operations
1573 - Default Environment:
1574 CONFIG_EXTRA_ENV_SETTINGS
1576 Define this to contain any number of null terminated
1577 strings (variable = value pairs) that will be part of
1578 the default environment compiled into the boot image.
1580 For example, place something like this in your
1581 board's config file:
1583 #define CONFIG_EXTRA_ENV_SETTINGS \
1587 Warning: This method is based on knowledge about the
1588 internal format how the environment is stored by the
1589 U-Boot code. This is NOT an official, exported
1590 interface! Although it is unlikely that this format
1591 will change soon, there is no guarantee either.
1592 You better know what you are doing here.
1594 Note: overly (ab)use of the default environment is
1595 discouraged. Make sure to check other ways to preset
1596 the environment like the autoscript function or the
1599 - DataFlash Support:
1600 CONFIG_HAS_DATAFLASH
1602 Defining this option enables DataFlash features and
1603 allows to read/write in Dataflash via the standard
1606 - SystemACE Support:
1609 Adding this option adds support for Xilinx SystemACE
1610 chips attached via some sort of local bus. The address
1611 of the chip must alsh be defined in the
1612 CFG_SYSTEMACE_BASE macro. For example:
1614 #define CONFIG_SYSTEMACE
1615 #define CFG_SYSTEMACE_BASE 0xf0000000
1617 When SystemACE support is added, the "ace" device type
1618 becomes available to the fat commands, i.e. fatls.
1620 - TFTP Fixed UDP Port:
1623 If this is defined, the environment variable tftpsrcp
1624 is used to supply the TFTP UDP source port value.
1625 If tftpsrcp isn't defined, the normal pseudo-random port
1626 number generator is used.
1628 Also, the environment variable tftpdstp is used to supply
1629 the TFTP UDP destination port value. If tftpdstp isn't
1630 defined, the normal port 69 is used.
1632 The purpose for tftpsrcp is to allow a TFTP server to
1633 blindly start the TFTP transfer using the pre-configured
1634 target IP address and UDP port. This has the effect of
1635 "punching through" the (Windows XP) firewall, allowing
1636 the remainder of the TFTP transfer to proceed normally.
1637 A better solution is to properly configure the firewall,
1638 but sometimes that is not allowed.
1640 - Show boot progress:
1641 CONFIG_SHOW_BOOT_PROGRESS
1643 Defining this option allows to add some board-
1644 specific code (calling a user-provided function
1645 "show_boot_progress(int)") that enables you to show
1646 the system's boot progress on some display (for
1647 example, some LED's) on your board. At the moment,
1648 the following checkpoints are implemented:
1651 1 common/cmd_bootm.c before attempting to boot an image
1652 -1 common/cmd_bootm.c Image header has bad magic number
1653 2 common/cmd_bootm.c Image header has correct magic number
1654 -2 common/cmd_bootm.c Image header has bad checksum
1655 3 common/cmd_bootm.c Image header has correct checksum
1656 -3 common/cmd_bootm.c Image data has bad checksum
1657 4 common/cmd_bootm.c Image data has correct checksum
1658 -4 common/cmd_bootm.c Image is for unsupported architecture
1659 5 common/cmd_bootm.c Architecture check OK
1660 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1661 6 common/cmd_bootm.c Image Type check OK
1662 -6 common/cmd_bootm.c gunzip uncompression error
1663 -7 common/cmd_bootm.c Unimplemented compression type
1664 7 common/cmd_bootm.c Uncompression OK
1665 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1666 8 common/cmd_bootm.c Image Type check OK
1667 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1668 9 common/cmd_bootm.c Start initial ramdisk verification
1669 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1670 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1671 10 common/cmd_bootm.c Ramdisk header is OK
1672 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1673 11 common/cmd_bootm.c Ramdisk data has correct checksum
1674 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1675 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1676 13 common/cmd_bootm.c Start multifile image verification
1677 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1678 15 common/cmd_bootm.c All preparation done, transferring control to OS
1680 -30 lib_ppc/board.c Fatal error, hang the system
1681 -31 post/post.c POST test failed, detected by post_output_backlog()
1682 -32 post/post.c POST test failed, detected by post_run_single()
1684 -1 common/cmd_doc.c Bad usage of "doc" command
1685 -1 common/cmd_doc.c No boot device
1686 -1 common/cmd_doc.c Unknown Chip ID on boot device
1687 -1 common/cmd_doc.c Read Error on boot device
1688 -1 common/cmd_doc.c Image header has bad magic number
1690 -1 common/cmd_ide.c Bad usage of "ide" command
1691 -1 common/cmd_ide.c No boot device
1692 -1 common/cmd_ide.c Unknown boot device
1693 -1 common/cmd_ide.c Unknown partition table
1694 -1 common/cmd_ide.c Invalid partition type
1695 -1 common/cmd_ide.c Read Error on boot device
1696 -1 common/cmd_ide.c Image header has bad magic number
1698 -1 common/cmd_nand.c Bad usage of "nand" command
1699 -1 common/cmd_nand.c No boot device
1700 -1 common/cmd_nand.c Unknown Chip ID on boot device
1701 -1 common/cmd_nand.c Read Error on boot device
1702 -1 common/cmd_nand.c Image header has bad magic number
1704 -1 common/env_common.c Environment has a bad CRC, using default
1710 [so far only for SMDK2400 and TRAB boards]
1712 - Modem support endable:
1713 CONFIG_MODEM_SUPPORT
1715 - RTS/CTS Flow control enable:
1718 - Modem debug support:
1719 CONFIG_MODEM_SUPPORT_DEBUG
1721 Enables debugging stuff (char screen[1024], dbg())
1722 for modem support. Useful only with BDI2000.
1724 - Interrupt support (PPC):
1726 There are common interrupt_init() and timer_interrupt()
1727 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1728 for cpu specific initialization. interrupt_init_cpu()
1729 should set decrementer_count to appropriate value. If
1730 cpu resets decrementer automatically after interrupt
1731 (ppc4xx) it should set decrementer_count to zero.
1732 timer_interrupt() calls timer_interrupt_cpu() for cpu
1733 specific handling. If board has watchdog / status_led
1734 / other_activity_monitor it works automatically from
1735 general timer_interrupt().
1739 In the target system modem support is enabled when a
1740 specific key (key combination) is pressed during
1741 power-on. Otherwise U-Boot will boot normally
1742 (autoboot). The key_pressed() fuction is called from
1743 board_init(). Currently key_pressed() is a dummy
1744 function, returning 1 and thus enabling modem
1747 If there are no modem init strings in the
1748 environment, U-Boot proceed to autoboot; the
1749 previous output (banner, info printfs) will be
1752 See also: doc/README.Modem
1755 Configuration Settings:
1756 -----------------------
1758 - CFG_LONGHELP: Defined when you want long help messages included;
1759 undefine this when you're short of memory.
1761 - CFG_PROMPT: This is what U-Boot prints on the console to
1762 prompt for user input.
1764 - CFG_CBSIZE: Buffer size for input from the Console
1766 - CFG_PBSIZE: Buffer size for Console output
1768 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1770 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1771 the application (usually a Linux kernel) when it is
1774 - CFG_BAUDRATE_TABLE:
1775 List of legal baudrate settings for this board.
1777 - CFG_CONSOLE_INFO_QUIET
1778 Suppress display of console information at boot.
1780 - CFG_CONSOLE_IS_IN_ENV
1781 If the board specific function
1782 extern int overwrite_console (void);
1783 returns 1, the stdin, stderr and stdout are switched to the
1784 serial port, else the settings in the environment are used.
1786 - CFG_CONSOLE_OVERWRITE_ROUTINE
1787 Enable the call to overwrite_console().
1789 - CFG_CONSOLE_ENV_OVERWRITE
1790 Enable overwrite of previous console environment settings.
1792 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1793 Begin and End addresses of the area used by the
1797 Enable an alternate, more extensive memory test.
1799 - CFG_MEMTEST_SCRATCH:
1800 Scratch address used by the alternate memory test
1801 You only need to set this if address zero isn't writeable
1803 - CFG_TFTP_LOADADDR:
1804 Default load address for network file downloads
1806 - CFG_LOADS_BAUD_CHANGE:
1807 Enable temporary baudrate change while serial download
1810 Physical start address of SDRAM. _Must_ be 0 here.
1813 Physical start address of Motherboard I/O (if using a
1817 Physical start address of Flash memory.
1820 Physical start address of boot monitor code (set by
1821 make config files to be same as the text base address
1822 (TEXT_BASE) used when linking) - same as
1823 CFG_FLASH_BASE when booting from flash.
1826 Size of memory reserved for monitor code, used to
1827 determine _at_compile_time_ (!) if the environment is
1828 embedded within the U-Boot image, or in a separate
1832 Size of DRAM reserved for malloc() use.
1835 Normally compressed uImages are limited to an
1836 uncompressed size of 8 MBytes. If this is not enough,
1837 you can define CFG_BOOTM_LEN in your board config file
1838 to adjust this setting to your needs.
1841 Maximum size of memory mapped by the startup code of
1842 the Linux kernel; all data that must be processed by
1843 the Linux kernel (bd_info, boot arguments, eventually
1844 initrd image) must be put below this limit.
1846 - CFG_MAX_FLASH_BANKS:
1847 Max number of Flash memory banks
1849 - CFG_MAX_FLASH_SECT:
1850 Max number of sectors on a Flash chip
1852 - CFG_FLASH_ERASE_TOUT:
1853 Timeout for Flash erase operations (in ms)
1855 - CFG_FLASH_WRITE_TOUT:
1856 Timeout for Flash write operations (in ms)
1858 - CFG_FLASH_LOCK_TOUT
1859 Timeout for Flash set sector lock bit operation (in ms)
1861 - CFG_FLASH_UNLOCK_TOUT
1862 Timeout for Flash clear lock bits operation (in ms)
1864 - CFG_FLASH_PROTECTION
1865 If defined, hardware flash sectors protection is used
1866 instead of U-Boot software protection.
1868 - CFG_DIRECT_FLASH_TFTP:
1870 Enable TFTP transfers directly to flash memory;
1871 without this option such a download has to be
1872 performed in two steps: (1) download to RAM, and (2)
1873 copy from RAM to flash.
1875 The two-step approach is usually more reliable, since
1876 you can check if the download worked before you erase
1877 the flash, but in some situations (when sytem RAM is
1878 too limited to allow for a tempory copy of the
1879 downloaded image) this option may be very useful.
1882 Define if the flash driver uses extra elements in the
1883 common flash structure for storing flash geometry.
1885 - CFG_FLASH_CFI_DRIVER
1886 This option also enables the building of the cfi_flash driver
1887 in the drivers directory
1889 - CFG_FLASH_QUIET_TEST
1890 If this option is defined, the common CFI flash doesn't
1891 print it's warning upon not recognized FLASH banks. This
1892 is useful, if some of the configured banks are only
1893 optionally available.
1895 - CFG_RX_ETH_BUFFER:
1896 Defines the number of ethernet receive buffers. On some
1897 ethernet controllers it is recommended to set this value
1898 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1899 buffers can be full shortly after enabling the interface
1900 on high ethernet traffic.
1901 Defaults to 4 if not defined.
1903 The following definitions that deal with the placement and management
1904 of environment data (variable area); in general, we support the
1905 following configurations:
1907 - CFG_ENV_IS_IN_FLASH:
1909 Define this if the environment is in flash memory.
1911 a) The environment occupies one whole flash sector, which is
1912 "embedded" in the text segment with the U-Boot code. This
1913 happens usually with "bottom boot sector" or "top boot
1914 sector" type flash chips, which have several smaller
1915 sectors at the start or the end. For instance, such a
1916 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1917 such a case you would place the environment in one of the
1918 4 kB sectors - with U-Boot code before and after it. With
1919 "top boot sector" type flash chips, you would put the
1920 environment in one of the last sectors, leaving a gap
1921 between U-Boot and the environment.
1925 Offset of environment data (variable area) to the
1926 beginning of flash memory; for instance, with bottom boot
1927 type flash chips the second sector can be used: the offset
1928 for this sector is given here.
1930 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1934 This is just another way to specify the start address of
1935 the flash sector containing the environment (instead of
1938 - CFG_ENV_SECT_SIZE:
1940 Size of the sector containing the environment.
1943 b) Sometimes flash chips have few, equal sized, BIG sectors.
1944 In such a case you don't want to spend a whole sector for
1949 If you use this in combination with CFG_ENV_IS_IN_FLASH
1950 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1951 of this flash sector for the environment. This saves
1952 memory for the RAM copy of the environment.
1954 It may also save flash memory if you decide to use this
1955 when your environment is "embedded" within U-Boot code,
1956 since then the remainder of the flash sector could be used
1957 for U-Boot code. It should be pointed out that this is
1958 STRONGLY DISCOURAGED from a robustness point of view:
1959 updating the environment in flash makes it always
1960 necessary to erase the WHOLE sector. If something goes
1961 wrong before the contents has been restored from a copy in
1962 RAM, your target system will be dead.
1964 - CFG_ENV_ADDR_REDUND
1967 These settings describe a second storage area used to hold
1968 a redundand copy of the environment data, so that there is
1969 a valid backup copy in case there is a power failure during
1970 a "saveenv" operation.
1972 BE CAREFUL! Any changes to the flash layout, and some changes to the
1973 source code will make it necessary to adapt <board>/u-boot.lds*
1977 - CFG_ENV_IS_IN_NVRAM:
1979 Define this if you have some non-volatile memory device
1980 (NVRAM, battery buffered SRAM) which you want to use for the
1986 These two #defines are used to determin the memory area you
1987 want to use for environment. It is assumed that this memory
1988 can just be read and written to, without any special
1991 BE CAREFUL! The first access to the environment happens quite early
1992 in U-Boot initalization (when we try to get the setting of for the
1993 console baudrate). You *MUST* have mappend your NVRAM area then, or
1996 Please note that even with NVRAM we still use a copy of the
1997 environment in RAM: we could work on NVRAM directly, but we want to
1998 keep settings there always unmodified except somebody uses "saveenv"
1999 to save the current settings.
2002 - CFG_ENV_IS_IN_EEPROM:
2004 Use this if you have an EEPROM or similar serial access
2005 device and a driver for it.
2010 These two #defines specify the offset and size of the
2011 environment area within the total memory of your EEPROM.
2013 - CFG_I2C_EEPROM_ADDR:
2014 If defined, specified the chip address of the EEPROM device.
2015 The default address is zero.
2017 - CFG_EEPROM_PAGE_WRITE_BITS:
2018 If defined, the number of bits used to address bytes in a
2019 single page in the EEPROM device. A 64 byte page, for example
2020 would require six bits.
2022 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2023 If defined, the number of milliseconds to delay between
2024 page writes. The default is zero milliseconds.
2026 - CFG_I2C_EEPROM_ADDR_LEN:
2027 The length in bytes of the EEPROM memory array address. Note
2028 that this is NOT the chip address length!
2030 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2031 EEPROM chips that implement "address overflow" are ones
2032 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2033 address and the extra bits end up in the "chip address" bit
2034 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2037 Note that we consider the length of the address field to
2038 still be one byte because the extra address bits are hidden
2039 in the chip address.
2042 The size in bytes of the EEPROM device.
2045 - CFG_ENV_IS_IN_DATAFLASH:
2047 Define this if you have a DataFlash memory device which you
2048 want to use for the environment.
2054 These three #defines specify the offset and size of the
2055 environment area within the total memory of your DataFlash placed
2056 at the specified address.
2058 - CFG_ENV_IS_IN_NAND:
2060 Define this if you have a NAND device which you want to use
2061 for the environment.
2066 These two #defines specify the offset and size of the environment
2067 area within the first NAND device.
2069 - CFG_ENV_OFFSET_REDUND
2071 This setting describes a second storage area of CFG_ENV_SIZE
2072 size used to hold a redundant copy of the environment data,
2073 so that there is a valid backup copy in case there is a
2074 power failure during a "saveenv" operation.
2076 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2077 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2078 the NAND devices block size.
2080 - CFG_SPI_INIT_OFFSET
2082 Defines offset to the initial SPI buffer area in DPRAM. The
2083 area is used at an early stage (ROM part) if the environment
2084 is configured to reside in the SPI EEPROM: We need a 520 byte
2085 scratch DPRAM area. It is used between the two initialization
2086 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2087 to be a good choice since it makes it far enough from the
2088 start of the data area as well as from the stack pointer.
2090 Please note that the environment is read-only as long as the monitor
2091 has been relocated to RAM and a RAM copy of the environment has been
2092 created; also, when using EEPROM you will have to use getenv_r()
2093 until then to read environment variables.
2095 The environment is protected by a CRC32 checksum. Before the monitor
2096 is relocated into RAM, as a result of a bad CRC you will be working
2097 with the compiled-in default environment - *silently*!!! [This is
2098 necessary, because the first environment variable we need is the
2099 "baudrate" setting for the console - if we have a bad CRC, we don't
2100 have any device yet where we could complain.]
2102 Note: once the monitor has been relocated, then it will complain if
2103 the default environment is used; a new CRC is computed as soon as you
2104 use the "saveenv" command to store a valid environment.
2106 - CFG_FAULT_ECHO_LINK_DOWN:
2107 Echo the inverted Ethernet link state to the fault LED.
2109 Note: If this option is active, then CFG_FAULT_MII_ADDR
2110 also needs to be defined.
2112 - CFG_FAULT_MII_ADDR:
2113 MII address of the PHY to check for the Ethernet link state.
2115 - CFG_64BIT_VSPRINTF:
2116 Makes vsprintf (and all *printf functions) support printing
2117 of 64bit values by using the L quantifier
2119 - CFG_64BIT_STRTOUL:
2120 Adds simple_strtoull that returns a 64bit value
2122 Low Level (hardware related) configuration options:
2123 ---------------------------------------------------
2125 - CFG_CACHELINE_SIZE:
2126 Cache Line Size of the CPU.
2129 Default address of the IMMR after system reset.
2131 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2132 and RPXsuper) to be able to adjust the position of
2133 the IMMR register after a reset.
2135 - Floppy Disk Support:
2136 CFG_FDC_DRIVE_NUMBER
2138 the default drive number (default value 0)
2142 defines the spacing between fdc chipset registers
2147 defines the offset of register from address. It
2148 depends on which part of the data bus is connected to
2149 the fdc chipset. (default value 0)
2151 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2152 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2155 if CFG_FDC_HW_INIT is defined, then the function
2156 fdc_hw_init() is called at the beginning of the FDC
2157 setup. fdc_hw_init() must be provided by the board
2158 source code. It is used to make hardware dependant
2161 - CFG_IMMR: Physical address of the Internal Memory.
2162 DO NOT CHANGE unless you know exactly what you're
2163 doing! (11-4) [MPC8xx/82xx systems only]
2165 - CFG_INIT_RAM_ADDR:
2167 Start address of memory area that can be used for
2168 initial data and stack; please note that this must be
2169 writable memory that is working WITHOUT special
2170 initialization, i. e. you CANNOT use normal RAM which
2171 will become available only after programming the
2172 memory controller and running certain initialization
2175 U-Boot uses the following memory types:
2176 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2177 - MPC824X: data cache
2178 - PPC4xx: data cache
2180 - CFG_GBL_DATA_OFFSET:
2182 Offset of the initial data structure in the memory
2183 area defined by CFG_INIT_RAM_ADDR. Usually
2184 CFG_GBL_DATA_OFFSET is chosen such that the initial
2185 data is located at the end of the available space
2186 (sometimes written as (CFG_INIT_RAM_END -
2187 CFG_INIT_DATA_SIZE), and the initial stack is just
2188 below that area (growing from (CFG_INIT_RAM_ADDR +
2189 CFG_GBL_DATA_OFFSET) downward.
2192 On the MPC824X (or other systems that use the data
2193 cache for initial memory) the address chosen for
2194 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2195 point to an otherwise UNUSED address space between
2196 the top of RAM and the start of the PCI space.
2198 - CFG_SIUMCR: SIU Module Configuration (11-6)
2200 - CFG_SYPCR: System Protection Control (11-9)
2202 - CFG_TBSCR: Time Base Status and Control (11-26)
2204 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2206 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2208 - CFG_SCCR: System Clock and reset Control Register (15-27)
2210 - CFG_OR_TIMING_SDRAM:
2214 periodic timer for refresh
2216 - CFG_DER: Debug Event Register (37-47)
2218 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2219 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2220 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2222 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2224 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2225 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2226 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2227 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2229 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2230 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2231 Machine Mode Register and Memory Periodic Timer
2232 Prescaler definitions (SDRAM timing)
2234 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2235 enable I2C microcode relocation patch (MPC8xx);
2236 define relocation offset in DPRAM [DSP2]
2238 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2239 enable SPI microcode relocation patch (MPC8xx);
2240 define relocation offset in DPRAM [SCC4]
2243 Use OSCM clock mode on MBX8xx board. Be careful,
2244 wrong setting might damage your board. Read
2245 doc/README.MBX before setting this variable!
2247 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2248 Offset of the bootmode word in DPRAM used by post
2249 (Power On Self Tests). This definition overrides
2250 #define'd default value in commproc.h resp.
2253 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2254 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2255 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2256 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2257 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2258 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2259 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2260 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2261 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2264 Get DDR timing information from an I2C EEPROM. Common with pluggable
2265 memory modules such as SODIMMs
2267 I2C address of the SPD EEPROM
2270 If SPD EEPROM is on an I2C bus other than the first one, specify here.
2271 Note that the value must resolve to something your driver can deal with.
2273 - CFG_83XX_DDR_USES_CS0
2274 Only for 83xx systems. If specified, then DDR should be configured
2275 using CS0 and CS1 instead of CS2 and CS3.
2277 - CFG_83XX_DDR_USES_CS0
2278 Only for 83xx systems. If specified, then DDR should be configured
2279 using CS0 and CS1 instead of CS2 and CS3.
2281 - CONFIG_ETHER_ON_FEC[12]
2282 Define to enable FEC[12] on a 8xx series processor.
2284 - CONFIG_FEC[12]_PHY
2285 Define to the hardcoded PHY address which corresponds
2286 to the given FEC; i. e.
2287 #define CONFIG_FEC1_PHY 4
2288 means that the PHY with address 4 is connected to FEC1
2290 When set to -1, means to probe for first available.
2292 - CONFIG_FEC[12]_PHY_NORXERR
2293 The PHY does not have a RXERR line (RMII only).
2294 (so program the FEC to ignore it).
2297 Enable RMII mode for all FECs.
2298 Note that this is a global option, we can't
2299 have one FEC in standard MII mode and another in RMII mode.
2301 - CONFIG_CRC32_VERIFY
2302 Add a verify option to the crc32 command.
2305 => crc32 -v <address> <count> <crc32>
2307 Where address/count indicate a memory area
2308 and crc32 is the correct crc32 which the
2312 Add the "loopw" memory command. This only takes effect if
2313 the memory commands are activated globally (CFG_CMD_MEM).
2316 Add the "mdc" and "mwc" memory commands. These are cyclic
2321 This command will print 4 bytes (10,11,12,13) each 500 ms.
2323 => mwc.l 100 12345678 10
2324 This command will write 12345678 to address 100 all 10 ms.
2326 This only takes effect if the memory commands are activated
2327 globally (CFG_CMD_MEM).
2329 - CONFIG_SKIP_LOWLEVEL_INIT
2330 - CONFIG_SKIP_RELOCATE_UBOOT
2332 [ARM only] If these variables are defined, then
2333 certain low level initializations (like setting up
2334 the memory controller) are omitted and/or U-Boot does
2335 not relocate itself into RAM.
2336 Normally these variables MUST NOT be defined. The
2337 only exception is when U-Boot is loaded (to RAM) by
2338 some other boot loader or by a debugger which
2339 performs these intializations itself.
2342 Building the Software:
2343 ======================
2345 Building U-Boot has been tested in native PPC environments (on a
2346 PowerBook G3 running LinuxPPC 2000) and in cross environments
2347 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2350 If you are not using a native PPC environment, it is assumed that you
2351 have the GNU cross compiling tools available in your path and named
2352 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2353 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2354 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2357 CROSS_COMPILE = ppc_4xx-
2360 U-Boot is intended to be simple to build. After installing the
2361 sources you must configure U-Boot for one specific board type. This
2366 where "NAME_config" is the name of one of the existing
2367 configurations; the following names are supported:
2369 ADCIOP_config FPS860L_config omap730p2_config
2370 ADS860_config GEN860T_config pcu_e_config
2372 AR405_config GENIETV_config PIP405_config
2373 at91rm9200dk_config GTH_config QS823_config
2374 CANBT_config hermes_config QS850_config
2375 cmi_mpc5xx_config hymod_config QS860T_config
2376 cogent_common_config IP860_config RPXlite_config
2377 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2378 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2379 CPCI405_config JSE_config rsdproto_config
2380 CPCIISER4_config LANTEC_config Sandpoint8240_config
2381 csb272_config lwmon_config sbc8260_config
2382 CU824_config MBX860T_config sbc8560_33_config
2383 DUET_ADS_config MBX_config sbc8560_66_config
2384 EBONY_config MPC8260ADS_config SM850_config
2385 ELPT860_config MPC8540ADS_config SPD823TS_config
2386 ESTEEM192E_config MPC8540EVAL_config stxgp3_config
2387 ETX094_config MPC8560ADS_config SXNI855T_config
2388 FADS823_config NETVIA_config TQM823L_config
2389 FADS850SAR_config omap1510inn_config TQM850L_config
2390 FADS860T_config omap1610h2_config TQM855L_config
2391 FPS850L_config omap1610inn_config TQM860L_config
2392 omap5912osk_config walnut_config
2393 omap2420h4_config Yukon8220_config
2396 Note: for some board special configuration names may exist; check if
2397 additional information is available from the board vendor; for
2398 instance, the TQM823L systems are available without (standard)
2399 or with LCD support. You can select such additional "features"
2400 when chosing the configuration, i. e.
2403 - will configure for a plain TQM823L, i. e. no LCD support
2405 make TQM823L_LCD_config
2406 - will configure for a TQM823L with U-Boot console on LCD
2411 Finally, type "make all", and you should get some working U-Boot
2412 images ready for download to / installation on your system:
2414 - "u-boot.bin" is a raw binary image
2415 - "u-boot" is an image in ELF binary format
2416 - "u-boot.srec" is in Motorola S-Record format
2418 By default the build is performed locally and the objects are saved
2419 in the source directory. One of the two methods can be used to change
2420 this behavior and build U-Boot to some external directory:
2422 1. Add O= to the make command line invocations:
2424 make O=/tmp/build distclean
2425 make O=/tmp/build NAME_config
2426 make O=/tmp/build all
2428 2. Set environment variable BUILD_DIR to point to the desired location:
2430 export BUILD_DIR=/tmp/build
2435 Note that the command line "O=" setting overrides the BUILD_DIR environment
2439 Please be aware that the Makefiles assume you are using GNU make, so
2440 for instance on NetBSD you might need to use "gmake" instead of
2444 If the system board that you have is not listed, then you will need
2445 to port U-Boot to your hardware platform. To do this, follow these
2448 1. Add a new configuration option for your board to the toplevel
2449 "Makefile" and to the "MAKEALL" script, using the existing
2450 entries as examples. Note that here and at many other places
2451 boards and other names are listed in alphabetical sort order. Please
2453 2. Create a new directory to hold your board specific code. Add any
2454 files you need. In your board directory, you will need at least
2455 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2456 3. Create a new configuration file "include/configs/<board>.h" for
2458 3. If you're porting U-Boot to a new CPU, then also create a new
2459 directory to hold your CPU specific code. Add any files you need.
2460 4. Run "make <board>_config" with your new name.
2461 5. Type "make", and you should get a working "u-boot.srec" file
2462 to be installed on your target system.
2463 6. Debug and solve any problems that might arise.
2464 [Of course, this last step is much harder than it sounds.]
2467 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2468 ==============================================================
2470 If you have modified U-Boot sources (for instance added a new board
2471 or support for new devices, a new CPU, etc.) you are expected to
2472 provide feedback to the other developers. The feedback normally takes
2473 the form of a "patch", i. e. a context diff against a certain (latest
2474 official or latest in CVS) version of U-Boot sources.
2476 But before you submit such a patch, please verify that your modifi-
2477 cation did not break existing code. At least make sure that *ALL* of
2478 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2479 just run the "MAKEALL" script, which will configure and build U-Boot
2480 for ALL supported system. Be warned, this will take a while. You can
2481 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2482 environment variable to the script, i. e. to use the cross tools from
2483 MontaVista's Hard Hat Linux you can type
2485 CROSS_COMPILE=ppc_8xx- MAKEALL
2487 or to build on a native PowerPC system you can type
2489 CROSS_COMPILE=' ' MAKEALL
2491 When using the MAKEALL script, the default behaviour is to build U-Boot
2492 in the source directory. This location can be changed by setting the
2493 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2494 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2495 <source dir>/LOG directory. This default location can be changed by
2496 setting the MAKEALL_LOGDIR environment variable. For example:
2498 export BUILD_DIR=/tmp/build
2499 export MAKEALL_LOGDIR=/tmp/log
2500 CROSS_COMPILE=ppc_8xx- MAKEALL
2502 With the above settings build objects are saved in the /tmp/build, log
2503 files are saved in the /tmp/log and the source tree remains clean during
2504 the whole build process.
2507 See also "U-Boot Porting Guide" below.
2510 Monitor Commands - Overview:
2511 ============================
2513 go - start application at address 'addr'
2514 run - run commands in an environment variable
2515 bootm - boot application image from memory
2516 bootp - boot image via network using BootP/TFTP protocol
2517 tftpboot- boot image via network using TFTP protocol
2518 and env variables "ipaddr" and "serverip"
2519 (and eventually "gatewayip")
2520 rarpboot- boot image via network using RARP/TFTP protocol
2521 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2522 loads - load S-Record file over serial line
2523 loadb - load binary file over serial line (kermit mode)
2525 mm - memory modify (auto-incrementing)
2526 nm - memory modify (constant address)
2527 mw - memory write (fill)
2529 cmp - memory compare
2530 crc32 - checksum calculation
2531 imd - i2c memory display
2532 imm - i2c memory modify (auto-incrementing)
2533 inm - i2c memory modify (constant address)
2534 imw - i2c memory write (fill)
2535 icrc32 - i2c checksum calculation
2536 iprobe - probe to discover valid I2C chip addresses
2537 iloop - infinite loop on address range
2538 isdram - print SDRAM configuration information
2539 sspi - SPI utility commands
2540 base - print or set address offset
2541 printenv- print environment variables
2542 setenv - set environment variables
2543 saveenv - save environment variables to persistent storage
2544 protect - enable or disable FLASH write protection
2545 erase - erase FLASH memory
2546 flinfo - print FLASH memory information
2547 bdinfo - print Board Info structure
2548 iminfo - print header information for application image
2549 coninfo - print console devices and informations
2550 ide - IDE sub-system
2551 loop - infinite loop on address range
2552 loopw - infinite write loop on address range
2553 mtest - simple RAM test
2554 icache - enable or disable instruction cache
2555 dcache - enable or disable data cache
2556 reset - Perform RESET of the CPU
2557 echo - echo args to console
2558 version - print monitor version
2559 help - print online help
2560 ? - alias for 'help'
2563 Monitor Commands - Detailed Description:
2564 ========================================
2568 For now: just type "help <command>".
2571 Environment Variables:
2572 ======================
2574 U-Boot supports user configuration using Environment Variables which
2575 can be made persistent by saving to Flash memory.
2577 Environment Variables are set using "setenv", printed using
2578 "printenv", and saved to Flash using "saveenv". Using "setenv"
2579 without a value can be used to delete a variable from the
2580 environment. As long as you don't save the environment you are
2581 working with an in-memory copy. In case the Flash area containing the
2582 environment is erased by accident, a default environment is provided.
2584 Some configuration options can be set using Environment Variables:
2586 baudrate - see CONFIG_BAUDRATE
2588 bootdelay - see CONFIG_BOOTDELAY
2590 bootcmd - see CONFIG_BOOTCOMMAND
2592 bootargs - Boot arguments when booting an RTOS image
2594 bootfile - Name of the image to load with TFTP
2596 autoload - if set to "no" (any string beginning with 'n'),
2597 "bootp" will just load perform a lookup of the
2598 configuration from the BOOTP server, but not try to
2599 load any image using TFTP
2601 autostart - if set to "yes", an image loaded using the "bootp",
2602 "rarpboot", "tftpboot" or "diskboot" commands will
2603 be automatically started (by internally calling
2606 If set to "no", a standalone image passed to the
2607 "bootm" command will be copied to the load address
2608 (and eventually uncompressed), but NOT be started.
2609 This can be used to load and uncompress arbitrary
2612 i2cfast - (PPC405GP|PPC405EP only)
2613 if set to 'y' configures Linux I2C driver for fast
2614 mode (400kHZ). This environment variable is used in
2615 initialization code. So, for changes to be effective
2616 it must be saved and board must be reset.
2618 initrd_high - restrict positioning of initrd images:
2619 If this variable is not set, initrd images will be
2620 copied to the highest possible address in RAM; this
2621 is usually what you want since it allows for
2622 maximum initrd size. If for some reason you want to
2623 make sure that the initrd image is loaded below the
2624 CFG_BOOTMAPSZ limit, you can set this environment
2625 variable to a value of "no" or "off" or "0".
2626 Alternatively, you can set it to a maximum upper
2627 address to use (U-Boot will still check that it
2628 does not overwrite the U-Boot stack and data).
2630 For instance, when you have a system with 16 MB
2631 RAM, and want to reserve 4 MB from use by Linux,
2632 you can do this by adding "mem=12M" to the value of
2633 the "bootargs" variable. However, now you must make
2634 sure that the initrd image is placed in the first
2635 12 MB as well - this can be done with
2637 setenv initrd_high 00c00000
2639 If you set initrd_high to 0xFFFFFFFF, this is an
2640 indication to U-Boot that all addresses are legal
2641 for the Linux kernel, including addresses in flash
2642 memory. In this case U-Boot will NOT COPY the
2643 ramdisk at all. This may be useful to reduce the
2644 boot time on your system, but requires that this
2645 feature is supported by your Linux kernel.
2647 ipaddr - IP address; needed for tftpboot command
2649 loadaddr - Default load address for commands like "bootp",
2650 "rarpboot", "tftpboot", "loadb" or "diskboot"
2652 loads_echo - see CONFIG_LOADS_ECHO
2654 serverip - TFTP server IP address; needed for tftpboot command
2656 bootretry - see CONFIG_BOOT_RETRY_TIME
2658 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2660 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2662 ethprime - When CONFIG_NET_MULTI is enabled controls which
2663 interface is used first.
2665 ethact - When CONFIG_NET_MULTI is enabled controls which
2666 interface is currently active. For example you
2667 can do the following
2669 => setenv ethact FEC ETHERNET
2670 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2671 => setenv ethact SCC ETHERNET
2672 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2674 netretry - When set to "no" each network operation will
2675 either succeed or fail without retrying.
2676 When set to "once" the network operation will
2677 fail when all the available network interfaces
2678 are tried once without success.
2679 Useful on scripts which control the retry operation
2682 tftpsrcport - If this is set, the value is used for TFTP's
2685 tftpdstport - If this is set, the value is used for TFTP's UDP
2686 destination port instead of the Well Know Port 69.
2688 vlan - When set to a value < 4095 the traffic over
2689 ethernet is encapsulated/received over 802.1q
2692 The following environment variables may be used and automatically
2693 updated by the network boot commands ("bootp" and "rarpboot"),
2694 depending the information provided by your boot server:
2696 bootfile - see above
2697 dnsip - IP address of your Domain Name Server
2698 dnsip2 - IP address of your secondary Domain Name Server
2699 gatewayip - IP address of the Gateway (Router) to use
2700 hostname - Target hostname
2702 netmask - Subnet Mask
2703 rootpath - Pathname of the root filesystem on the NFS server
2704 serverip - see above
2707 There are two special Environment Variables:
2709 serial# - contains hardware identification information such
2710 as type string and/or serial number
2711 ethaddr - Ethernet address
2713 These variables can be set only once (usually during manufacturing of
2714 the board). U-Boot refuses to delete or overwrite these variables
2715 once they have been set once.
2718 Further special Environment Variables:
2720 ver - Contains the U-Boot version string as printed
2721 with the "version" command. This variable is
2722 readonly (see CONFIG_VERSION_VARIABLE).
2725 Please note that changes to some configuration parameters may take
2726 only effect after the next boot (yes, that's just like Windoze :-).
2729 Command Line Parsing:
2730 =====================
2732 There are two different command line parsers available with U-Boot:
2733 the old "simple" one, and the much more powerful "hush" shell:
2735 Old, simple command line parser:
2736 --------------------------------
2738 - supports environment variables (through setenv / saveenv commands)
2739 - several commands on one line, separated by ';'
2740 - variable substitution using "... ${name} ..." syntax
2741 - special characters ('$', ';') can be escaped by prefixing with '\',
2743 setenv bootcmd bootm \${address}
2744 - You can also escape text by enclosing in single apostrophes, for example:
2745 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2750 - similar to Bourne shell, with control structures like
2751 if...then...else...fi, for...do...done; while...do...done,
2752 until...do...done, ...
2753 - supports environment ("global") variables (through setenv / saveenv
2754 commands) and local shell variables (through standard shell syntax
2755 "name=value"); only environment variables can be used with "run"
2761 (1) If a command line (or an environment variable executed by a "run"
2762 command) contains several commands separated by semicolon, and
2763 one of these commands fails, then the remaining commands will be
2766 (2) If you execute several variables with one call to run (i. e.
2767 calling run with a list af variables as arguments), any failing
2768 command will cause "run" to terminate, i. e. the remaining
2769 variables are not executed.
2771 Note for Redundant Ethernet Interfaces:
2772 =======================================
2774 Some boards come with redundant ethernet interfaces; U-Boot supports
2775 such configurations and is capable of automatic selection of a
2776 "working" interface when needed. MAC assignment works as follows:
2778 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2779 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2780 "eth1addr" (=>eth1), "eth2addr", ...
2782 If the network interface stores some valid MAC address (for instance
2783 in SROM), this is used as default address if there is NO correspon-
2784 ding setting in the environment; if the corresponding environment
2785 variable is set, this overrides the settings in the card; that means:
2787 o If the SROM has a valid MAC address, and there is no address in the
2788 environment, the SROM's address is used.
2790 o If there is no valid address in the SROM, and a definition in the
2791 environment exists, then the value from the environment variable is
2794 o If both the SROM and the environment contain a MAC address, and
2795 both addresses are the same, this MAC address is used.
2797 o If both the SROM and the environment contain a MAC address, and the
2798 addresses differ, the value from the environment is used and a
2801 o If neither SROM nor the environment contain a MAC address, an error
2808 The "boot" commands of this monitor operate on "image" files which
2809 can be basicly anything, preceeded by a special header; see the
2810 definitions in include/image.h for details; basicly, the header
2811 defines the following image properties:
2813 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2814 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2815 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2816 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2817 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2818 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2819 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2820 * Compression Type (uncompressed, gzip, bzip2)
2826 The header is marked by a special Magic Number, and both the header
2827 and the data portions of the image are secured against corruption by
2834 Although U-Boot should support any OS or standalone application
2835 easily, the main focus has always been on Linux during the design of
2838 U-Boot includes many features that so far have been part of some
2839 special "boot loader" code within the Linux kernel. Also, any
2840 "initrd" images to be used are no longer part of one big Linux image;
2841 instead, kernel and "initrd" are separate images. This implementation
2842 serves several purposes:
2844 - the same features can be used for other OS or standalone
2845 applications (for instance: using compressed images to reduce the
2846 Flash memory footprint)
2848 - it becomes much easier to port new Linux kernel versions because
2849 lots of low-level, hardware dependent stuff are done by U-Boot
2851 - the same Linux kernel image can now be used with different "initrd"
2852 images; of course this also means that different kernel images can
2853 be run with the same "initrd". This makes testing easier (you don't
2854 have to build a new "zImage.initrd" Linux image when you just
2855 change a file in your "initrd"). Also, a field-upgrade of the
2856 software is easier now.
2862 Porting Linux to U-Boot based systems:
2863 ---------------------------------------
2865 U-Boot cannot save you from doing all the necessary modifications to
2866 configure the Linux device drivers for use with your target hardware
2867 (no, we don't intend to provide a full virtual machine interface to
2870 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2872 Just make sure your machine specific header file (for instance
2873 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2874 Information structure as we define in include/u-boot.h, and make
2875 sure that your definition of IMAP_ADDR uses the same value as your
2876 U-Boot configuration in CFG_IMMR.
2879 Configuring the Linux kernel:
2880 -----------------------------
2882 No specific requirements for U-Boot. Make sure you have some root
2883 device (initial ramdisk, NFS) for your target system.
2886 Building a Linux Image:
2887 -----------------------
2889 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2890 not used. If you use recent kernel source, a new build target
2891 "uImage" will exist which automatically builds an image usable by
2892 U-Boot. Most older kernels also have support for a "pImage" target,
2893 which was introduced for our predecessor project PPCBoot and uses a
2894 100% compatible format.
2903 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2904 encapsulate a compressed Linux kernel image with header information,
2905 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2907 * build a standard "vmlinux" kernel image (in ELF binary format):
2909 * convert the kernel into a raw binary image:
2911 ${CROSS_COMPILE}-objcopy -O binary \
2912 -R .note -R .comment \
2913 -S vmlinux linux.bin
2915 * compress the binary image:
2919 * package compressed binary image for U-Boot:
2921 mkimage -A ppc -O linux -T kernel -C gzip \
2922 -a 0 -e 0 -n "Linux Kernel Image" \
2923 -d linux.bin.gz uImage
2926 The "mkimage" tool can also be used to create ramdisk images for use
2927 with U-Boot, either separated from the Linux kernel image, or
2928 combined into one file. "mkimage" encapsulates the images with a 64
2929 byte header containing information about target architecture,
2930 operating system, image type, compression method, entry points, time
2931 stamp, CRC32 checksums, etc.
2933 "mkimage" can be called in two ways: to verify existing images and
2934 print the header information, or to build new images.
2936 In the first form (with "-l" option) mkimage lists the information
2937 contained in the header of an existing U-Boot image; this includes
2938 checksum verification:
2940 tools/mkimage -l image
2941 -l ==> list image header information
2943 The second form (with "-d" option) is used to build a U-Boot image
2944 from a "data file" which is used as image payload:
2946 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2947 -n name -d data_file image
2948 -A ==> set architecture to 'arch'
2949 -O ==> set operating system to 'os'
2950 -T ==> set image type to 'type'
2951 -C ==> set compression type 'comp'
2952 -a ==> set load address to 'addr' (hex)
2953 -e ==> set entry point to 'ep' (hex)
2954 -n ==> set image name to 'name'
2955 -d ==> use image data from 'datafile'
2957 Right now, all Linux kernels for PowerPC systems use the same load
2958 address (0x00000000), but the entry point address depends on the
2961 - 2.2.x kernels have the entry point at 0x0000000C,
2962 - 2.3.x and later kernels have the entry point at 0x00000000.
2964 So a typical call to build a U-Boot image would read:
2966 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2967 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2968 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2969 > 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 To verify the contents of the image (or check for corruption):
2979 -> tools/mkimage -l examples/uImage.TQM850L
2980 Image Name: 2.4.4 kernel for TQM850L
2981 Created: Wed Jul 19 02:34:59 2000
2982 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2983 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2984 Load Address: 0x00000000
2985 Entry Point: 0x00000000
2987 NOTE: for embedded systems where boot time is critical you can trade
2988 speed for memory and install an UNCOMPRESSED image instead: this
2989 needs more space in Flash, but boots much faster since it does not
2990 need to be uncompressed:
2992 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2993 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2994 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2995 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2996 > examples/uImage.TQM850L-uncompressed
2997 Image Name: 2.4.4 kernel for TQM850L
2998 Created: Wed Jul 19 02:34:59 2000
2999 Image Type: PowerPC Linux Kernel Image (uncompressed)
3000 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3001 Load Address: 0x00000000
3002 Entry Point: 0x00000000
3005 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3006 when your kernel is intended to use an initial ramdisk:
3008 -> tools/mkimage -n 'Simple Ramdisk Image' \
3009 > -A ppc -O linux -T ramdisk -C gzip \
3010 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3011 Image Name: Simple Ramdisk Image
3012 Created: Wed Jan 12 14:01:50 2000
3013 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3014 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3015 Load Address: 0x00000000
3016 Entry Point: 0x00000000
3019 Installing a Linux Image:
3020 -------------------------
3022 To downloading a U-Boot image over the serial (console) interface,
3023 you must convert the image to S-Record format:
3025 objcopy -I binary -O srec examples/image examples/image.srec
3027 The 'objcopy' does not understand the information in the U-Boot
3028 image header, so the resulting S-Record file will be relative to
3029 address 0x00000000. To load it to a given address, you need to
3030 specify the target address as 'offset' parameter with the 'loads'
3033 Example: install the image to address 0x40100000 (which on the
3034 TQM8xxL is in the first Flash bank):
3036 => erase 40100000 401FFFFF
3042 ## Ready for S-Record download ...
3043 ~>examples/image.srec
3044 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3046 15989 15990 15991 15992
3047 [file transfer complete]
3049 ## Start Addr = 0x00000000
3052 You can check the success of the download using the 'iminfo' command;
3053 this includes a checksum verification so you can be sure no data
3054 corruption happened:
3058 ## Checking Image at 40100000 ...
3059 Image Name: 2.2.13 for initrd on TQM850L
3060 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3061 Data Size: 335725 Bytes = 327 kB = 0 MB
3062 Load Address: 00000000
3063 Entry Point: 0000000c
3064 Verifying Checksum ... OK
3070 The "bootm" command is used to boot an application that is stored in
3071 memory (RAM or Flash). In case of a Linux kernel image, the contents
3072 of the "bootargs" environment variable is passed to the kernel as
3073 parameters. You can check and modify this variable using the
3074 "printenv" and "setenv" commands:
3077 => printenv bootargs
3078 bootargs=root=/dev/ram
3080 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3082 => printenv bootargs
3083 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3086 ## Booting Linux kernel at 40020000 ...
3087 Image Name: 2.2.13 for NFS on TQM850L
3088 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3089 Data Size: 381681 Bytes = 372 kB = 0 MB
3090 Load Address: 00000000
3091 Entry Point: 0000000c
3092 Verifying Checksum ... OK
3093 Uncompressing Kernel Image ... OK
3094 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
3095 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3096 time_init: decrementer frequency = 187500000/60
3097 Calibrating delay loop... 49.77 BogoMIPS
3098 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3101 If you want to boot a Linux kernel with initial ram disk, you pass
3102 the memory addresses of both the kernel and the initrd image (PPBCOOT
3103 format!) to the "bootm" command:
3105 => imi 40100000 40200000
3107 ## Checking Image at 40100000 ...
3108 Image Name: 2.2.13 for initrd on TQM850L
3109 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3110 Data Size: 335725 Bytes = 327 kB = 0 MB
3111 Load Address: 00000000
3112 Entry Point: 0000000c
3113 Verifying Checksum ... OK
3115 ## Checking Image at 40200000 ...
3116 Image Name: Simple Ramdisk Image
3117 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3118 Data Size: 566530 Bytes = 553 kB = 0 MB
3119 Load Address: 00000000
3120 Entry Point: 00000000
3121 Verifying Checksum ... OK
3123 => bootm 40100000 40200000
3124 ## Booting Linux kernel at 40100000 ...
3125 Image Name: 2.2.13 for initrd on TQM850L
3126 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3127 Data Size: 335725 Bytes = 327 kB = 0 MB
3128 Load Address: 00000000
3129 Entry Point: 0000000c
3130 Verifying Checksum ... OK
3131 Uncompressing Kernel Image ... OK
3132 ## Loading RAMDisk Image at 40200000 ...
3133 Image Name: Simple Ramdisk Image
3134 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3135 Data Size: 566530 Bytes = 553 kB = 0 MB
3136 Load Address: 00000000
3137 Entry Point: 00000000
3138 Verifying Checksum ... OK
3139 Loading Ramdisk ... OK
3140 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
3141 Boot arguments: root=/dev/ram
3142 time_init: decrementer frequency = 187500000/60
3143 Calibrating delay loop... 49.77 BogoMIPS
3145 RAMDISK: Compressed image found at block 0
3146 VFS: Mounted root (ext2 filesystem).
3150 Boot Linux and pass a flat device tree:
3153 First, U-Boot must be compiled with the appropriate defines. See the section
3154 titled "Linux Kernel Interface" above for a more in depth explanation. The
3155 following is an example of how to start a kernel and pass an updated
3161 oft=oftrees/mpc8540ads.dtb
3162 => tftp $oftaddr $oft
3163 Speed: 1000, full duplex
3165 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3166 Filename 'oftrees/mpc8540ads.dtb'.
3167 Load address: 0x300000
3170 Bytes transferred = 4106 (100a hex)
3171 => tftp $loadaddr $bootfile
3172 Speed: 1000, full duplex
3174 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3176 Load address: 0x200000
3177 Loading:############
3179 Bytes transferred = 1029407 (fb51f hex)
3184 => bootm $loadaddr - $oftaddr
3185 ## Booting image at 00200000 ...
3186 Image Name: Linux-2.6.17-dirty
3187 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3188 Data Size: 1029343 Bytes = 1005.2 kB
3189 Load Address: 00000000
3190 Entry Point: 00000000
3191 Verifying Checksum ... OK
3192 Uncompressing Kernel Image ... OK
3193 Booting using flat device tree at 0x300000
3194 Using MPC85xx ADS machine description
3195 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3199 More About U-Boot Image Types:
3200 ------------------------------
3202 U-Boot supports the following image types:
3204 "Standalone Programs" are directly runnable in the environment
3205 provided by U-Boot; it is expected that (if they behave
3206 well) you can continue to work in U-Boot after return from
3207 the Standalone Program.
3208 "OS Kernel Images" are usually images of some Embedded OS which
3209 will take over control completely. Usually these programs
3210 will install their own set of exception handlers, device
3211 drivers, set up the MMU, etc. - this means, that you cannot
3212 expect to re-enter U-Boot except by resetting the CPU.
3213 "RAMDisk Images" are more or less just data blocks, and their
3214 parameters (address, size) are passed to an OS kernel that is
3216 "Multi-File Images" contain several images, typically an OS
3217 (Linux) kernel image and one or more data images like
3218 RAMDisks. This construct is useful for instance when you want
3219 to boot over the network using BOOTP etc., where the boot
3220 server provides just a single image file, but you want to get
3221 for instance an OS kernel and a RAMDisk image.
3223 "Multi-File Images" start with a list of image sizes, each
3224 image size (in bytes) specified by an "uint32_t" in network
3225 byte order. This list is terminated by an "(uint32_t)0".
3226 Immediately after the terminating 0 follow the images, one by
3227 one, all aligned on "uint32_t" boundaries (size rounded up to
3228 a multiple of 4 bytes).
3230 "Firmware Images" are binary images containing firmware (like
3231 U-Boot or FPGA images) which usually will be programmed to
3234 "Script files" are command sequences that will be executed by
3235 U-Boot's command interpreter; this feature is especially
3236 useful when you configure U-Boot to use a real shell (hush)
3237 as command interpreter.
3243 One of the features of U-Boot is that you can dynamically load and
3244 run "standalone" applications, which can use some resources of
3245 U-Boot like console I/O functions or interrupt services.
3247 Two simple examples are included with the sources:
3252 'examples/hello_world.c' contains a small "Hello World" Demo
3253 application; it is automatically compiled when you build U-Boot.
3254 It's configured to run at address 0x00040004, so you can play with it
3258 ## Ready for S-Record download ...
3259 ~>examples/hello_world.srec
3260 1 2 3 4 5 6 7 8 9 10 11 ...
3261 [file transfer complete]
3263 ## Start Addr = 0x00040004
3265 => go 40004 Hello World! This is a test.
3266 ## Starting application at 0x00040004 ...
3277 Hit any key to exit ...
3279 ## Application terminated, rc = 0x0
3281 Another example, which demonstrates how to register a CPM interrupt
3282 handler with the U-Boot code, can be found in 'examples/timer.c'.
3283 Here, a CPM timer is set up to generate an interrupt every second.
3284 The interrupt service routine is trivial, just printing a '.'
3285 character, but this is just a demo program. The application can be
3286 controlled by the following keys:
3288 ? - print current values og the CPM Timer registers
3289 b - enable interrupts and start timer
3290 e - stop timer and disable interrupts
3291 q - quit application
3294 ## Ready for S-Record download ...
3295 ~>examples/timer.srec
3296 1 2 3 4 5 6 7 8 9 10 11 ...
3297 [file transfer complete]
3299 ## Start Addr = 0x00040004
3302 ## Starting application at 0x00040004 ...
3305 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3308 [q, b, e, ?] Set interval 1000000 us
3311 [q, b, e, ?] ........
3312 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3315 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3318 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3321 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3323 [q, b, e, ?] ...Stopping timer
3325 [q, b, e, ?] ## Application terminated, rc = 0x0
3331 Over time, many people have reported problems when trying to use the
3332 "minicom" terminal emulation program for serial download. I (wd)
3333 consider minicom to be broken, and recommend not to use it. Under
3334 Unix, I recommend to use C-Kermit for general purpose use (and
3335 especially for kermit binary protocol download ("loadb" command), and
3336 use "cu" for S-Record download ("loads" command).
3338 Nevertheless, if you absolutely want to use it try adding this
3339 configuration to your "File transfer protocols" section:
3341 Name Program Name U/D FullScr IO-Red. Multi
3342 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3343 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3349 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3350 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3352 Building requires a cross environment; it is known to work on
3353 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3354 need gmake since the Makefiles are not compatible with BSD make).
3355 Note that the cross-powerpc package does not install include files;
3356 attempting to build U-Boot will fail because <machine/ansi.h> is
3357 missing. This file has to be installed and patched manually:
3359 # cd /usr/pkg/cross/powerpc-netbsd/include
3361 # ln -s powerpc machine
3362 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3363 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3365 Native builds *don't* work due to incompatibilities between native
3366 and U-Boot include files.
3368 Booting assumes that (the first part of) the image booted is a
3369 stage-2 loader which in turn loads and then invokes the kernel
3370 proper. Loader sources will eventually appear in the NetBSD source
3371 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3372 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3375 Implementation Internals:
3376 =========================
3378 The following is not intended to be a complete description of every
3379 implementation detail. However, it should help to understand the
3380 inner workings of U-Boot and make it easier to port it to custom
3384 Initial Stack, Global Data:
3385 ---------------------------
3387 The implementation of U-Boot is complicated by the fact that U-Boot
3388 starts running out of ROM (flash memory), usually without access to
3389 system RAM (because the memory controller is not initialized yet).
3390 This means that we don't have writable Data or BSS segments, and BSS
3391 is not initialized as zero. To be able to get a C environment working
3392 at all, we have to allocate at least a minimal stack. Implementation
3393 options for this are defined and restricted by the CPU used: Some CPU
3394 models provide on-chip memory (like the IMMR area on MPC8xx and
3395 MPC826x processors), on others (parts of) the data cache can be
3396 locked as (mis-) used as memory, etc.
3398 Chris Hallinan posted a good summary of these issues to the
3399 u-boot-users mailing list:
3401 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3402 From: "Chris Hallinan" <clh@net1plus.com>
3403 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3406 Correct me if I'm wrong, folks, but the way I understand it
3407 is this: Using DCACHE as initial RAM for Stack, etc, does not
3408 require any physical RAM backing up the cache. The cleverness
3409 is that the cache is being used as a temporary supply of
3410 necessary storage before the SDRAM controller is setup. It's
3411 beyond the scope of this list to expain the details, but you
3412 can see how this works by studying the cache architecture and
3413 operation in the architecture and processor-specific manuals.
3415 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3416 is another option for the system designer to use as an
3417 initial stack/ram area prior to SDRAM being available. Either
3418 option should work for you. Using CS 4 should be fine if your
3419 board designers haven't used it for something that would
3420 cause you grief during the initial boot! It is frequently not
3423 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3424 with your processor/board/system design. The default value
3425 you will find in any recent u-boot distribution in
3426 walnut.h should work for you. I'd set it to a value larger
3427 than your SDRAM module. If you have a 64MB SDRAM module, set
3428 it above 400_0000. Just make sure your board has no resources
3429 that are supposed to respond to that address! That code in
3430 start.S has been around a while and should work as is when
3431 you get the config right.
3436 It is essential to remember this, since it has some impact on the C
3437 code for the initialization procedures:
3439 * Initialized global data (data segment) is read-only. Do not attempt
3442 * Do not use any unitialized global data (or implicitely initialized
3443 as zero data - BSS segment) at all - this is undefined, initiali-
3444 zation is performed later (when relocating to RAM).
3446 * Stack space is very limited. Avoid big data buffers or things like
3449 Having only the stack as writable memory limits means we cannot use
3450 normal global data to share information beween the code. But it
3451 turned out that the implementation of U-Boot can be greatly
3452 simplified by making a global data structure (gd_t) available to all
3453 functions. We could pass a pointer to this data as argument to _all_
3454 functions, but this would bloat the code. Instead we use a feature of
3455 the GCC compiler (Global Register Variables) to share the data: we
3456 place a pointer (gd) to the global data into a register which we
3457 reserve for this purpose.
3459 When choosing a register for such a purpose we are restricted by the
3460 relevant (E)ABI specifications for the current architecture, and by
3461 GCC's implementation.
3463 For PowerPC, the following registers have specific use:
3466 R3-R4: parameter passing and return values
3467 R5-R10: parameter passing
3468 R13: small data area pointer
3472 (U-Boot also uses R14 as internal GOT pointer.)
3474 ==> U-Boot will use R29 to hold a pointer to the global data
3476 Note: on PPC, we could use a static initializer (since the
3477 address of the global data structure is known at compile time),
3478 but it turned out that reserving a register results in somewhat
3479 smaller code - although the code savings are not that big (on
3480 average for all boards 752 bytes for the whole U-Boot image,
3481 624 text + 127 data).
3483 On ARM, the following registers are used:
3485 R0: function argument word/integer result
3486 R1-R3: function argument word
3488 R10: stack limit (used only if stack checking if enabled)
3489 R11: argument (frame) pointer
3490 R12: temporary workspace
3493 R15: program counter
3495 ==> U-Boot will use R8 to hold a pointer to the global data
3497 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3498 or current versions of GCC may "optimize" the code too much.
3503 U-Boot runs in system state and uses physical addresses, i.e. the
3504 MMU is not used either for address mapping nor for memory protection.
3506 The available memory is mapped to fixed addresses using the memory
3507 controller. In this process, a contiguous block is formed for each
3508 memory type (Flash, SDRAM, SRAM), even when it consists of several
3509 physical memory banks.
3511 U-Boot is installed in the first 128 kB of the first Flash bank (on
3512 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3513 booting and sizing and initializing DRAM, the code relocates itself
3514 to the upper end of DRAM. Immediately below the U-Boot code some
3515 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3516 configuration setting]. Below that, a structure with global Board
3517 Info data is placed, followed by the stack (growing downward).
3519 Additionally, some exception handler code is copied to the low 8 kB
3520 of DRAM (0x00000000 ... 0x00001FFF).
3522 So a typical memory configuration with 16 MB of DRAM could look like
3525 0x0000 0000 Exception Vector code
3528 0x0000 2000 Free for Application Use
3534 0x00FB FF20 Monitor Stack (Growing downward)
3535 0x00FB FFAC Board Info Data and permanent copy of global data
3536 0x00FC 0000 Malloc Arena
3539 0x00FE 0000 RAM Copy of Monitor Code
3540 ... eventually: LCD or video framebuffer
3541 ... eventually: pRAM (Protected RAM - unchanged by reset)
3542 0x00FF FFFF [End of RAM]
3545 System Initialization:
3546 ----------------------
3548 In the reset configuration, U-Boot starts at the reset entry point
3549 (on most PowerPC systens at address 0x00000100). Because of the reset
3550 configuration for CS0# this is a mirror of the onboard Flash memory.
3551 To be able to re-map memory U-Boot then jumps to its link address.
3552 To be able to implement the initialization code in C, a (small!)
3553 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3554 which provide such a feature like MPC8xx or MPC8260), or in a locked
3555 part of the data cache. After that, U-Boot initializes the CPU core,
3556 the caches and the SIU.
3558 Next, all (potentially) available memory banks are mapped using a
3559 preliminary mapping. For example, we put them on 512 MB boundaries
3560 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3561 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3562 programmed for SDRAM access. Using the temporary configuration, a
3563 simple memory test is run that determines the size of the SDRAM
3566 When there is more than one SDRAM bank, and the banks are of
3567 different size, the largest is mapped first. For equal size, the first
3568 bank (CS2#) is mapped first. The first mapping is always for address
3569 0x00000000, with any additional banks following immediately to create
3570 contiguous memory starting from 0.
3572 Then, the monitor installs itself at the upper end of the SDRAM area
3573 and allocates memory for use by malloc() and for the global Board
3574 Info data; also, the exception vector code is copied to the low RAM
3575 pages, and the final stack is set up.
3577 Only after this relocation will you have a "normal" C environment;
3578 until that you are restricted in several ways, mostly because you are
3579 running from ROM, and because the code will have to be relocated to a
3583 U-Boot Porting Guide:
3584 ----------------------
3586 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3590 int main (int argc, char *argv[])
3592 sighandler_t no_more_time;
3594 signal (SIGALRM, no_more_time);
3595 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3597 if (available_money > available_manpower) {
3598 pay consultant to port U-Boot;
3602 Download latest U-Boot source;
3604 Subscribe to u-boot-users mailing list;
3607 email ("Hi, I am new to U-Boot, how do I get started?");
3611 Read the README file in the top level directory;
3612 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3613 Read the source, Luke;
3616 if (available_money > toLocalCurrency ($2500)) {
3619 Add a lot of aggravation and time;
3622 Create your own board support subdirectory;
3624 Create your own board config file;
3628 Add / modify source code;
3632 email ("Hi, I am having problems...");
3634 Send patch file to Wolfgang;
3639 void no_more_time (int sig)
3648 All contributions to U-Boot should conform to the Linux kernel
3649 coding style; see the file "Documentation/CodingStyle" and the script
3650 "scripts/Lindent" in your Linux kernel source directory. In sources
3651 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3652 spaces before parameters to function calls) is actually used.
3654 Source files originating from a different project (for example the
3655 MTD subsystem) are generally exempt from these guidelines and are not
3656 reformated to ease subsequent migration to newer versions of those
3659 Please note that U-Boot is implemented in C (and to some small parts in
3660 Assembler); no C++ is used, so please do not use C++ style comments (//)
3663 Please also stick to the following formatting rules:
3664 - remove any trailing white space
3665 - use TAB characters for indentation, not spaces
3666 - make sure NOT to use DOS '\r\n' line feeds
3667 - do not add more than 2 empty lines to source files
3668 - do not add trailing empty lines to source files
3670 Submissions which do not conform to the standards may be returned
3671 with a request to reformat the changes.
3677 Since the number of patches for U-Boot is growing, we need to
3678 establish some rules. Submissions which do not conform to these rules
3679 may be rejected, even when they contain important and valuable stuff.
3681 Patches shall be sent to the u-boot-users mailing list.
3683 When you send a patch, please include the following information with
3686 * For bug fixes: a description of the bug and how your patch fixes
3687 this bug. Please try to include a way of demonstrating that the
3688 patch actually fixes something.
3690 * For new features: a description of the feature and your
3693 * A CHANGELOG entry as plaintext (separate from the patch)
3695 * For major contributions, your entry to the CREDITS file
3697 * When you add support for a new board, don't forget to add this
3698 board to the MAKEALL script, too.
3700 * If your patch adds new configuration options, don't forget to
3701 document these in the README file.
3703 * The patch itself. If you are accessing the CVS repository use "cvs
3704 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3705 version of diff does not support these options, then get the latest
3706 version of GNU diff.
3708 The current directory when running this command shall be the top
3709 level directory of the U-Boot source tree, or it's parent directory
3710 (i. e. please make sure that your patch includes sufficient
3711 directory information for the affected files).
3713 We accept patches as plain text, MIME attachments or as uuencoded
3716 * If one logical set of modifications affects or creates several
3717 files, all these changes shall be submitted in a SINGLE patch file.
3719 * Changesets that contain different, unrelated modifications shall be
3720 submitted as SEPARATE patches, one patch per changeset.
3725 * Before sending the patch, run the MAKEALL script on your patched
3726 source tree and make sure that no errors or warnings are reported
3727 for any of the boards.
3729 * Keep your modifications to the necessary minimum: A patch
3730 containing several unrelated changes or arbitrary reformats will be
3731 returned with a request to re-formatting / split it.
3733 * If you modify existing code, make sure that your new code does not
3734 add to the memory footprint of the code ;-) Small is beautiful!
3735 When adding new features, these should compile conditionally only
3736 (using #ifdef), and the resulting code with the new feature
3737 disabled must not need more memory than the old code without your
3740 * Remember that there is a size limit of 40 kB per message on the
3741 u-boot-users mailing list. Compression may help.
projects / platform / kernel / u-boot.git / blob