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
887 Define the below if you wish to use the USB console.
888 Once firmware is rebuilt from a serial console issue the
889 command "setenv stdin usbtty; setenv stdout usbtty" and
890 attach your usb cable. The Unix command "dmesg" should print
891 it has found a new device. The environment variable usbtty
892 can be set to gserial or cdc_acm to enable your device to
893 appear to a USB host as a Linux gserial device or a
894 Common Device Class Abstract Control Model serial device.
895 If you select usbtty = gserial you should be able to enumerate
897 # modprobe usbserial vendor=0xVendorID product=0xProductID
898 else if using cdc_acm, simply setting the environment
899 variable usbtty to be cdc_acm should suffice. The following
900 might be defined in YourBoardName.h
903 Define this to build a UDC device
906 Define this to have a tty type of device available to
907 talk to the UDC device
909 CFG_CONSOLE_IS_IN_ENV
910 Define this if you want stdin, stdout &/or stderr to
914 CFG_USB_EXTC_CLK 0xBLAH
915 Derive USB clock from external clock "blah"
916 - CFG_USB_EXTC_CLK 0x02
918 CFG_USB_BRG_CLK 0xBLAH
919 Derive USB clock from brgclk
920 - CFG_USB_BRG_CLK 0x04
922 If you have a USB-IF assigned VendorID then you may wish to
923 define your own vendor specific values either in BoardName.h
924 or directly in usbd_vendor_info.h. If you don't define
925 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
926 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
927 should pretend to be a Linux device to it's target host.
929 CONFIG_USBD_MANUFACTURER
930 Define this string as the name of your company for
931 - CONFIG_USBD_MANUFACTURER "my company"
933 CONFIG_USBD_PRODUCT_NAME
934 Define this string as the name of your product
935 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
938 Define this as your assigned Vendor ID from the USB
939 Implementors Forum. This *must* be a genuine Vendor ID
940 to avoid polluting the USB namespace.
941 - CONFIG_USBD_VENDORID 0xFFFF
943 CONFIG_USBD_PRODUCTID
944 Define this as the unique Product ID
946 - CONFIG_USBD_PRODUCTID 0xFFFF
950 The MMC controller on the Intel PXA is supported. To
951 enable this define CONFIG_MMC. The MMC can be
952 accessed from the boot prompt by mapping the device
953 to physical memory similar to flash. Command line is
954 enabled with CFG_CMD_MMC. The MMC driver also works with
955 the FAT fs. This is enabled with CFG_CMD_FAT.
957 - Journaling Flash filesystem support:
958 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
959 CONFIG_JFFS2_NAND_DEV
960 Define these for a default partition on a NAND device
962 CFG_JFFS2_FIRST_SECTOR,
963 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
964 Define these for a default partition on a NOR device
967 Define this to create an own partition. You have to provide a
968 function struct part_info* jffs2_part_info(int part_num)
970 If you define only one JFFS2 partition you may also want to
971 #define CFG_JFFS_SINGLE_PART 1
972 to disable the command chpart. This is the default when you
973 have not defined a custom partition
978 Define this to enable standard (PC-Style) keyboard
982 Standard PC keyboard driver with US (is default) and
983 GERMAN key layout (switch via environment 'keymap=de') support.
984 Export function i8042_kbd_init, i8042_tstc and i8042_getc
985 for cfb_console. Supports cursor blinking.
990 Define this to enable video support (for output to
995 Enable Chips & Technologies 69000 Video chip
997 CONFIG_VIDEO_SMI_LYNXEM
998 Enable Silicon Motion SMI 712/710/810 Video chip. The
999 video output is selected via environment 'videoout'
1000 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1003 For the CT69000 and SMI_LYNXEM drivers, videomode is
1004 selected via environment 'videomode'. Two diferent ways
1006 - "videomode=num" 'num' is a standard LiLo mode numbers.
1007 Following standard modes are supported (* is default):
1009 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1010 -------------+---------------------------------------------
1011 8 bits | 0x301* 0x303 0x305 0x161 0x307
1012 15 bits | 0x310 0x313 0x316 0x162 0x319
1013 16 bits | 0x311 0x314 0x317 0x163 0x31A
1014 24 bits | 0x312 0x315 0x318 ? 0x31B
1015 -------------+---------------------------------------------
1016 (i.e. setenv videomode 317; saveenv; reset;)
1018 - "videomode=bootargs" all the video parameters are parsed
1019 from the bootargs. (See drivers/videomodes.c)
1022 CONFIG_VIDEO_SED13806
1023 Enable Epson SED13806 driver. This driver supports 8bpp
1024 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1025 or CONFIG_VIDEO_SED13806_16BPP
1030 Define this to enable a custom keyboard support.
1031 This simply calls drv_keyboard_init() which must be
1032 defined in your board-specific files.
1033 The only board using this so far is RBC823.
1035 - LCD Support: CONFIG_LCD
1037 Define this to enable LCD support (for output to LCD
1038 display); also select one of the supported displays
1039 by defining one of these:
1041 CONFIG_NEC_NL6448AC33:
1043 NEC NL6448AC33-18. Active, color, single scan.
1045 CONFIG_NEC_NL6448BC20
1047 NEC NL6448BC20-08. 6.5", 640x480.
1048 Active, color, single scan.
1050 CONFIG_NEC_NL6448BC33_54
1052 NEC NL6448BC33-54. 10.4", 640x480.
1053 Active, color, single scan.
1057 Sharp 320x240. Active, color, single scan.
1058 It isn't 16x9, and I am not sure what it is.
1060 CONFIG_SHARP_LQ64D341
1062 Sharp LQ64D341 display, 640x480.
1063 Active, color, single scan.
1067 HLD1045 display, 640x480.
1068 Active, color, single scan.
1072 Optrex CBL50840-2 NF-FW 99 22 M5
1074 Hitachi LMG6912RPFC-00T
1078 320x240. Black & white.
1080 Normally display is black on white background; define
1081 CFG_WHITE_ON_BLACK to get it inverted.
1083 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1085 If this option is set, the environment is checked for
1086 a variable "splashimage". If found, the usual display
1087 of logo, copyright and system information on the LCD
1088 is suppressed and the BMP image at the address
1089 specified in "splashimage" is loaded instead. The
1090 console is redirected to the "nulldev", too. This
1091 allows for a "silent" boot where a splash screen is
1092 loaded very quickly after power-on.
1094 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1096 If this option is set, additionally to standard BMP
1097 images, gzipped BMP images can be displayed via the
1098 splashscreen support or the bmp command.
1100 - Compression support:
1103 If this option is set, support for bzip2 compressed
1104 images is included. If not, only uncompressed and gzip
1105 compressed images are supported.
1107 NOTE: the bzip2 algorithm requires a lot of RAM, so
1108 the malloc area (as defined by CFG_MALLOC_LEN) should
1114 The address of PHY on MII bus.
1116 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1118 The clock frequency of the MII bus
1122 If this option is set, support for speed/duplex
1123 detection of Gigabit PHY is included.
1125 CONFIG_PHY_RESET_DELAY
1127 Some PHY like Intel LXT971A need extra delay after
1128 reset before any MII register access is possible.
1129 For such PHY, set this option to the usec delay
1130 required. (minimum 300usec for LXT971A)
1132 CONFIG_PHY_CMD_DELAY (ppc4xx)
1134 Some PHY like Intel LXT971A need extra delay after
1135 command issued before MII status register can be read
1142 Define a default value for ethernet address to use
1143 for the respective ethernet interface, in case this
1144 is not determined automatically.
1149 Define a default value for the IP address to use for
1150 the default ethernet interface, in case this is not
1151 determined through e.g. bootp.
1153 - Server IP address:
1156 Defines a default value for theIP address of a TFTP
1157 server to contact when using the "tftboot" command.
1159 - BOOTP Recovery Mode:
1160 CONFIG_BOOTP_RANDOM_DELAY
1162 If you have many targets in a network that try to
1163 boot using BOOTP, you may want to avoid that all
1164 systems send out BOOTP requests at precisely the same
1165 moment (which would happen for instance at recovery
1166 from a power failure, when all systems will try to
1167 boot, thus flooding the BOOTP server. Defining
1168 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1169 inserted before sending out BOOTP requests. The
1170 following delays are insterted then:
1172 1st BOOTP request: delay 0 ... 1 sec
1173 2nd BOOTP request: delay 0 ... 2 sec
1174 3rd BOOTP request: delay 0 ... 4 sec
1176 BOOTP requests: delay 0 ... 8 sec
1178 - DHCP Advanced Options:
1181 You can fine tune the DHCP functionality by adding
1182 these flags to the CONFIG_BOOTP_MASK define:
1184 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1185 serverip from a DHCP server, it is possible that more
1186 than one DNS serverip is offered to the client.
1187 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1188 serverip will be stored in the additional environment
1189 variable "dnsip2". The first DNS serverip is always
1190 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1191 is added to the CONFIG_BOOTP_MASK.
1193 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1194 to do a dynamic update of a DNS server. To do this, they
1195 need the hostname of the DHCP requester.
1196 If CONFIG_BOOP_SEND_HOSTNAME is added to the
1197 CONFIG_BOOTP_MASK, the content of the "hostname"
1198 environment variable is passed as option 12 to
1202 CONFIG_CDP_DEVICE_ID
1204 The device id used in CDP trigger frames.
1206 CONFIG_CDP_DEVICE_ID_PREFIX
1208 A two character string which is prefixed to the MAC address
1213 A printf format string which contains the ascii name of
1214 the port. Normally is set to "eth%d" which sets
1215 eth0 for the first ethernet, eth1 for the second etc.
1217 CONFIG_CDP_CAPABILITIES
1219 A 32bit integer which indicates the device capabilities;
1220 0x00000010 for a normal host which does not forwards.
1224 An ascii string containing the version of the software.
1228 An ascii string containing the name of the platform.
1232 A 32bit integer sent on the trigger.
1234 CONFIG_CDP_POWER_CONSUMPTION
1236 A 16bit integer containing the power consumption of the
1237 device in .1 of milliwatts.
1239 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1241 A byte containing the id of the VLAN.
1243 - Status LED: CONFIG_STATUS_LED
1245 Several configurations allow to display the current
1246 status using a LED. For instance, the LED will blink
1247 fast while running U-Boot code, stop blinking as
1248 soon as a reply to a BOOTP request was received, and
1249 start blinking slow once the Linux kernel is running
1250 (supported by a status LED driver in the Linux
1251 kernel). Defining CONFIG_STATUS_LED enables this
1254 - CAN Support: CONFIG_CAN_DRIVER
1256 Defining CONFIG_CAN_DRIVER enables CAN driver support
1257 on those systems that support this (optional)
1258 feature, like the TQM8xxL modules.
1260 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1262 These enable I2C serial bus commands. Defining either of
1263 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1264 include the appropriate I2C driver for the selected cpu.
1266 This will allow you to use i2c commands at the u-boot
1267 command line (as long as you set CFG_CMD_I2C in
1268 CONFIG_COMMANDS) and communicate with i2c based realtime
1269 clock chips. See common/cmd_i2c.c for a description of the
1270 command line interface.
1272 CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
1274 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1275 bit-banging) driver instead of CPM or similar hardware
1278 There are several other quantities that must also be
1279 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1281 In both cases you will need to define CFG_I2C_SPEED
1282 to be the frequency (in Hz) at which you wish your i2c bus
1283 to run and CFG_I2C_SLAVE to be the address of this node (ie
1284 the cpu's i2c node address).
1286 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1287 sets the cpu up as a master node and so its address should
1288 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1289 p.16-473). So, set CFG_I2C_SLAVE to 0.
1291 That's all that's required for CONFIG_HARD_I2C.
1293 If you use the software i2c interface (CONFIG_SOFT_I2C)
1294 then the following macros need to be defined (examples are
1295 from include/configs/lwmon.h):
1299 (Optional). Any commands necessary to enable the I2C
1300 controller or configure ports.
1302 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1306 (Only for MPC8260 CPU). The I/O port to use (the code
1307 assumes both bits are on the same port). Valid values
1308 are 0..3 for ports A..D.
1312 The code necessary to make the I2C data line active
1313 (driven). If the data line is open collector, this
1316 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1320 The code necessary to make the I2C data line tri-stated
1321 (inactive). If the data line is open collector, this
1324 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1328 Code that returns TRUE if the I2C data line is high,
1331 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1335 If <bit> is TRUE, sets the I2C data line high. If it
1336 is FALSE, it clears it (low).
1338 eg: #define I2C_SDA(bit) \
1339 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1340 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1344 If <bit> is TRUE, sets the I2C clock line high. If it
1345 is FALSE, it clears it (low).
1347 eg: #define I2C_SCL(bit) \
1348 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1349 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1353 This delay is invoked four times per clock cycle so this
1354 controls the rate of data transfer. The data rate thus
1355 is 1 / (I2C_DELAY * 4). Often defined to be something
1358 #define I2C_DELAY udelay(2)
1362 When a board is reset during an i2c bus transfer
1363 chips might think that the current transfer is still
1364 in progress. On some boards it is possible to access
1365 the i2c SCLK line directly, either by using the
1366 processor pin as a GPIO or by having a second pin
1367 connected to the bus. If this option is defined a
1368 custom i2c_init_board() routine in boards/xxx/board.c
1369 is run early in the boot sequence.
1371 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1373 This option enables configuration of bi_iic_fast[] flags
1374 in u-boot bd_info structure based on u-boot environment
1375 variable "i2cfast". (see also i2cfast)
1377 - SPI Support: CONFIG_SPI
1379 Enables SPI driver (so far only tested with
1380 SPI EEPROM, also an instance works with Crystal A/D and
1381 D/As on the SACSng board)
1385 Enables extended (16-bit) SPI EEPROM addressing.
1386 (symmetrical to CONFIG_I2C_X)
1390 Enables a software (bit-bang) SPI driver rather than
1391 using hardware support. This is a general purpose
1392 driver that only requires three general I/O port pins
1393 (two outputs, one input) to function. If this is
1394 defined, the board configuration must define several
1395 SPI configuration items (port pins to use, etc). For
1396 an example, see include/configs/sacsng.h.
1398 - FPGA Support: CONFIG_FPGA_COUNT
1400 Specify the number of FPGA devices to support.
1404 Used to specify the types of FPGA devices. For example,
1405 #define CONFIG_FPGA CFG_XILINX_VIRTEX2
1407 CFG_FPGA_PROG_FEEDBACK
1409 Enable printing of hash marks during FPGA configuration.
1413 Enable checks on FPGA configuration interface busy
1414 status by the configuration function. This option
1415 will require a board or device specific function to
1420 If defined, a function that provides delays in the FPGA
1421 configuration driver.
1423 CFG_FPGA_CHECK_CTRLC
1424 Allow Control-C to interrupt FPGA configuration
1426 CFG_FPGA_CHECK_ERROR
1428 Check for configuration errors during FPGA bitfile
1429 loading. For example, abort during Virtex II
1430 configuration if the INIT_B line goes low (which
1431 indicated a CRC error).
1435 Maximum time to wait for the INIT_B line to deassert
1436 after PROB_B has been deasserted during a Virtex II
1437 FPGA configuration sequence. The default time is 500
1442 Maximum time to wait for BUSY to deassert during
1443 Virtex II FPGA configuration. The default is 5 mS.
1445 CFG_FPGA_WAIT_CONFIG
1447 Time to wait after FPGA configuration. The default is
1450 - Configuration Management:
1453 If defined, this string will be added to the U-Boot
1454 version information (U_BOOT_VERSION)
1456 - Vendor Parameter Protection:
1458 U-Boot considers the values of the environment
1459 variables "serial#" (Board Serial Number) and
1460 "ethaddr" (Ethernet Address) to be parameters that
1461 are set once by the board vendor / manufacturer, and
1462 protects these variables from casual modification by
1463 the user. Once set, these variables are read-only,
1464 and write or delete attempts are rejected. You can
1465 change this behviour:
1467 If CONFIG_ENV_OVERWRITE is #defined in your config
1468 file, the write protection for vendor parameters is
1469 completely disabled. Anybody can change or delete
1472 Alternatively, if you #define _both_ CONFIG_ETHADDR
1473 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1474 ethernet address is installed in the environment,
1475 which can be changed exactly ONCE by the user. [The
1476 serial# is unaffected by this, i. e. it remains
1482 Define this variable to enable the reservation of
1483 "protected RAM", i. e. RAM which is not overwritten
1484 by U-Boot. Define CONFIG_PRAM to hold the number of
1485 kB you want to reserve for pRAM. You can overwrite
1486 this default value by defining an environment
1487 variable "pram" to the number of kB you want to
1488 reserve. Note that the board info structure will
1489 still show the full amount of RAM. If pRAM is
1490 reserved, a new environment variable "mem" will
1491 automatically be defined to hold the amount of
1492 remaining RAM in a form that can be passed as boot
1493 argument to Linux, for instance like that:
1495 setenv bootargs ... mem=\${mem}
1498 This way you can tell Linux not to use this memory,
1499 either, which results in a memory region that will
1500 not be affected by reboots.
1502 *WARNING* If your board configuration uses automatic
1503 detection of the RAM size, you must make sure that
1504 this memory test is non-destructive. So far, the
1505 following board configurations are known to be
1508 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1509 HERMES, IP860, RPXlite, LWMON, LANTEC,
1510 PCU_E, FLAGADM, TQM8260
1515 Define this variable to stop the system in case of a
1516 fatal error, so that you have to reset it manually.
1517 This is probably NOT a good idea for an embedded
1518 system where you want to system to reboot
1519 automatically as fast as possible, but it may be
1520 useful during development since you can try to debug
1521 the conditions that lead to the situation.
1523 CONFIG_NET_RETRY_COUNT
1525 This variable defines the number of retries for
1526 network operations like ARP, RARP, TFTP, or BOOTP
1527 before giving up the operation. If not defined, a
1528 default value of 5 is used.
1530 - Command Interpreter:
1531 CONFIG_AUTO_COMPLETE
1533 Enable auto completion of commands using TAB.
1535 Note that this feature has NOT been implemented yet
1536 for the "hush" shell.
1541 Define this variable to enable the "hush" shell (from
1542 Busybox) as command line interpreter, thus enabling
1543 powerful command line syntax like
1544 if...then...else...fi conditionals or `&&' and '||'
1545 constructs ("shell scripts").
1547 If undefined, you get the old, much simpler behaviour
1548 with a somewhat smaller memory footprint.
1553 This defines the secondary prompt string, which is
1554 printed when the command interpreter needs more input
1555 to complete a command. Usually "> ".
1559 In the current implementation, the local variables
1560 space and global environment variables space are
1561 separated. Local variables are those you define by
1562 simply typing `name=value'. To access a local
1563 variable later on, you have write `$name' or
1564 `${name}'; to execute the contents of a variable
1565 directly type `$name' at the command prompt.
1567 Global environment variables are those you use
1568 setenv/printenv to work with. To run a command stored
1569 in such a variable, you need to use the run command,
1570 and you must not use the '$' sign to access them.
1572 To store commands and special characters in a
1573 variable, please use double quotation marks
1574 surrounding the whole text of the variable, instead
1575 of the backslashes before semicolons and special
1578 - Commandline Editing and History:
1579 CONFIG_CMDLINE_EDITING
1581 Enable editiong and History functions for interactive
1582 commandline input operations
1584 - Default Environment:
1585 CONFIG_EXTRA_ENV_SETTINGS
1587 Define this to contain any number of null terminated
1588 strings (variable = value pairs) that will be part of
1589 the default environment compiled into the boot image.
1591 For example, place something like this in your
1592 board's config file:
1594 #define CONFIG_EXTRA_ENV_SETTINGS \
1598 Warning: This method is based on knowledge about the
1599 internal format how the environment is stored by the
1600 U-Boot code. This is NOT an official, exported
1601 interface! Although it is unlikely that this format
1602 will change soon, there is no guarantee either.
1603 You better know what you are doing here.
1605 Note: overly (ab)use of the default environment is
1606 discouraged. Make sure to check other ways to preset
1607 the environment like the autoscript function or the
1610 - DataFlash Support:
1611 CONFIG_HAS_DATAFLASH
1613 Defining this option enables DataFlash features and
1614 allows to read/write in Dataflash via the standard
1617 - SystemACE Support:
1620 Adding this option adds support for Xilinx SystemACE
1621 chips attached via some sort of local bus. The address
1622 of the chip must alsh be defined in the
1623 CFG_SYSTEMACE_BASE macro. For example:
1625 #define CONFIG_SYSTEMACE
1626 #define CFG_SYSTEMACE_BASE 0xf0000000
1628 When SystemACE support is added, the "ace" device type
1629 becomes available to the fat commands, i.e. fatls.
1631 - TFTP Fixed UDP Port:
1634 If this is defined, the environment variable tftpsrcp
1635 is used to supply the TFTP UDP source port value.
1636 If tftpsrcp isn't defined, the normal pseudo-random port
1637 number generator is used.
1639 Also, the environment variable tftpdstp is used to supply
1640 the TFTP UDP destination port value. If tftpdstp isn't
1641 defined, the normal port 69 is used.
1643 The purpose for tftpsrcp is to allow a TFTP server to
1644 blindly start the TFTP transfer using the pre-configured
1645 target IP address and UDP port. This has the effect of
1646 "punching through" the (Windows XP) firewall, allowing
1647 the remainder of the TFTP transfer to proceed normally.
1648 A better solution is to properly configure the firewall,
1649 but sometimes that is not allowed.
1651 - Show boot progress:
1652 CONFIG_SHOW_BOOT_PROGRESS
1654 Defining this option allows to add some board-
1655 specific code (calling a user-provided function
1656 "show_boot_progress(int)") that enables you to show
1657 the system's boot progress on some display (for
1658 example, some LED's) on your board. At the moment,
1659 the following checkpoints are implemented:
1662 1 common/cmd_bootm.c before attempting to boot an image
1663 -1 common/cmd_bootm.c Image header has bad magic number
1664 2 common/cmd_bootm.c Image header has correct magic number
1665 -2 common/cmd_bootm.c Image header has bad checksum
1666 3 common/cmd_bootm.c Image header has correct checksum
1667 -3 common/cmd_bootm.c Image data has bad checksum
1668 4 common/cmd_bootm.c Image data has correct checksum
1669 -4 common/cmd_bootm.c Image is for unsupported architecture
1670 5 common/cmd_bootm.c Architecture check OK
1671 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1672 6 common/cmd_bootm.c Image Type check OK
1673 -6 common/cmd_bootm.c gunzip uncompression error
1674 -7 common/cmd_bootm.c Unimplemented compression type
1675 7 common/cmd_bootm.c Uncompression OK
1676 -8 common/cmd_bootm.c Wrong Image Type (not kernel, multi, standalone)
1677 8 common/cmd_bootm.c Image Type check OK
1678 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1679 9 common/cmd_bootm.c Start initial ramdisk verification
1680 -10 common/cmd_bootm.c Ramdisk header has bad magic number
1681 -11 common/cmd_bootm.c Ramdisk header has bad checksum
1682 10 common/cmd_bootm.c Ramdisk header is OK
1683 -12 common/cmd_bootm.c Ramdisk data has bad checksum
1684 11 common/cmd_bootm.c Ramdisk data has correct checksum
1685 12 common/cmd_bootm.c Ramdisk verification complete, start loading
1686 -13 common/cmd_bootm.c Wrong Image Type (not PPC Linux Ramdisk)
1687 13 common/cmd_bootm.c Start multifile image verification
1688 14 common/cmd_bootm.c No initial ramdisk, no multifile, continue.
1689 15 common/cmd_bootm.c All preparation done, transferring control to OS
1691 -30 lib_ppc/board.c Fatal error, hang the system
1692 -31 post/post.c POST test failed, detected by post_output_backlog()
1693 -32 post/post.c POST test failed, detected by post_run_single()
1695 -1 common/cmd_doc.c Bad usage of "doc" command
1696 -1 common/cmd_doc.c No boot device
1697 -1 common/cmd_doc.c Unknown Chip ID on boot device
1698 -1 common/cmd_doc.c Read Error on boot device
1699 -1 common/cmd_doc.c Image header has bad magic number
1701 -1 common/cmd_ide.c Bad usage of "ide" command
1702 -1 common/cmd_ide.c No boot device
1703 -1 common/cmd_ide.c Unknown boot device
1704 -1 common/cmd_ide.c Unknown partition table
1705 -1 common/cmd_ide.c Invalid partition type
1706 -1 common/cmd_ide.c Read Error on boot device
1707 -1 common/cmd_ide.c Image header has bad magic number
1709 -1 common/cmd_nand.c Bad usage of "nand" command
1710 -1 common/cmd_nand.c No boot device
1711 -1 common/cmd_nand.c Unknown Chip ID on boot device
1712 -1 common/cmd_nand.c Read Error on boot device
1713 -1 common/cmd_nand.c Image header has bad magic number
1715 -1 common/env_common.c Environment has a bad CRC, using default
1721 [so far only for SMDK2400 and TRAB boards]
1723 - Modem support endable:
1724 CONFIG_MODEM_SUPPORT
1726 - RTS/CTS Flow control enable:
1729 - Modem debug support:
1730 CONFIG_MODEM_SUPPORT_DEBUG
1732 Enables debugging stuff (char screen[1024], dbg())
1733 for modem support. Useful only with BDI2000.
1735 - Interrupt support (PPC):
1737 There are common interrupt_init() and timer_interrupt()
1738 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1739 for cpu specific initialization. interrupt_init_cpu()
1740 should set decrementer_count to appropriate value. If
1741 cpu resets decrementer automatically after interrupt
1742 (ppc4xx) it should set decrementer_count to zero.
1743 timer_interrupt() calls timer_interrupt_cpu() for cpu
1744 specific handling. If board has watchdog / status_led
1745 / other_activity_monitor it works automatically from
1746 general timer_interrupt().
1750 In the target system modem support is enabled when a
1751 specific key (key combination) is pressed during
1752 power-on. Otherwise U-Boot will boot normally
1753 (autoboot). The key_pressed() fuction is called from
1754 board_init(). Currently key_pressed() is a dummy
1755 function, returning 1 and thus enabling modem
1758 If there are no modem init strings in the
1759 environment, U-Boot proceed to autoboot; the
1760 previous output (banner, info printfs) will be
1763 See also: doc/README.Modem
1766 Configuration Settings:
1767 -----------------------
1769 - CFG_LONGHELP: Defined when you want long help messages included;
1770 undefine this when you're short of memory.
1772 - CFG_PROMPT: This is what U-Boot prints on the console to
1773 prompt for user input.
1775 - CFG_CBSIZE: Buffer size for input from the Console
1777 - CFG_PBSIZE: Buffer size for Console output
1779 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1781 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1782 the application (usually a Linux kernel) when it is
1785 - CFG_BAUDRATE_TABLE:
1786 List of legal baudrate settings for this board.
1788 - CFG_CONSOLE_INFO_QUIET
1789 Suppress display of console information at boot.
1791 - CFG_CONSOLE_IS_IN_ENV
1792 If the board specific function
1793 extern int overwrite_console (void);
1794 returns 1, the stdin, stderr and stdout are switched to the
1795 serial port, else the settings in the environment are used.
1797 - CFG_CONSOLE_OVERWRITE_ROUTINE
1798 Enable the call to overwrite_console().
1800 - CFG_CONSOLE_ENV_OVERWRITE
1801 Enable overwrite of previous console environment settings.
1803 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1804 Begin and End addresses of the area used by the
1808 Enable an alternate, more extensive memory test.
1810 - CFG_MEMTEST_SCRATCH:
1811 Scratch address used by the alternate memory test
1812 You only need to set this if address zero isn't writeable
1814 - CFG_TFTP_LOADADDR:
1815 Default load address for network file downloads
1817 - CFG_LOADS_BAUD_CHANGE:
1818 Enable temporary baudrate change while serial download
1821 Physical start address of SDRAM. _Must_ be 0 here.
1824 Physical start address of Motherboard I/O (if using a
1828 Physical start address of Flash memory.
1831 Physical start address of boot monitor code (set by
1832 make config files to be same as the text base address
1833 (TEXT_BASE) used when linking) - same as
1834 CFG_FLASH_BASE when booting from flash.
1837 Size of memory reserved for monitor code, used to
1838 determine _at_compile_time_ (!) if the environment is
1839 embedded within the U-Boot image, or in a separate
1843 Size of DRAM reserved for malloc() use.
1846 Normally compressed uImages are limited to an
1847 uncompressed size of 8 MBytes. If this is not enough,
1848 you can define CFG_BOOTM_LEN in your board config file
1849 to adjust this setting to your needs.
1852 Maximum size of memory mapped by the startup code of
1853 the Linux kernel; all data that must be processed by
1854 the Linux kernel (bd_info, boot arguments, eventually
1855 initrd image) must be put below this limit.
1857 - CFG_MAX_FLASH_BANKS:
1858 Max number of Flash memory banks
1860 - CFG_MAX_FLASH_SECT:
1861 Max number of sectors on a Flash chip
1863 - CFG_FLASH_ERASE_TOUT:
1864 Timeout for Flash erase operations (in ms)
1866 - CFG_FLASH_WRITE_TOUT:
1867 Timeout for Flash write operations (in ms)
1869 - CFG_FLASH_LOCK_TOUT
1870 Timeout for Flash set sector lock bit operation (in ms)
1872 - CFG_FLASH_UNLOCK_TOUT
1873 Timeout for Flash clear lock bits operation (in ms)
1875 - CFG_FLASH_PROTECTION
1876 If defined, hardware flash sectors protection is used
1877 instead of U-Boot software protection.
1879 - CFG_DIRECT_FLASH_TFTP:
1881 Enable TFTP transfers directly to flash memory;
1882 without this option such a download has to be
1883 performed in two steps: (1) download to RAM, and (2)
1884 copy from RAM to flash.
1886 The two-step approach is usually more reliable, since
1887 you can check if the download worked before you erase
1888 the flash, but in some situations (when sytem RAM is
1889 too limited to allow for a tempory copy of the
1890 downloaded image) this option may be very useful.
1893 Define if the flash driver uses extra elements in the
1894 common flash structure for storing flash geometry.
1896 - CFG_FLASH_CFI_DRIVER
1897 This option also enables the building of the cfi_flash driver
1898 in the drivers directory
1900 - CFG_FLASH_QUIET_TEST
1901 If this option is defined, the common CFI flash doesn't
1902 print it's warning upon not recognized FLASH banks. This
1903 is useful, if some of the configured banks are only
1904 optionally available.
1906 - CFG_RX_ETH_BUFFER:
1907 Defines the number of ethernet receive buffers. On some
1908 ethernet controllers it is recommended to set this value
1909 to 8 or even higher (EEPRO100 or 405 EMAC), since all
1910 buffers can be full shortly after enabling the interface
1911 on high ethernet traffic.
1912 Defaults to 4 if not defined.
1914 The following definitions that deal with the placement and management
1915 of environment data (variable area); in general, we support the
1916 following configurations:
1918 - CFG_ENV_IS_IN_FLASH:
1920 Define this if the environment is in flash memory.
1922 a) The environment occupies one whole flash sector, which is
1923 "embedded" in the text segment with the U-Boot code. This
1924 happens usually with "bottom boot sector" or "top boot
1925 sector" type flash chips, which have several smaller
1926 sectors at the start or the end. For instance, such a
1927 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
1928 such a case you would place the environment in one of the
1929 4 kB sectors - with U-Boot code before and after it. With
1930 "top boot sector" type flash chips, you would put the
1931 environment in one of the last sectors, leaving a gap
1932 between U-Boot and the environment.
1936 Offset of environment data (variable area) to the
1937 beginning of flash memory; for instance, with bottom boot
1938 type flash chips the second sector can be used: the offset
1939 for this sector is given here.
1941 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
1945 This is just another way to specify the start address of
1946 the flash sector containing the environment (instead of
1949 - CFG_ENV_SECT_SIZE:
1951 Size of the sector containing the environment.
1954 b) Sometimes flash chips have few, equal sized, BIG sectors.
1955 In such a case you don't want to spend a whole sector for
1960 If you use this in combination with CFG_ENV_IS_IN_FLASH
1961 and CFG_ENV_SECT_SIZE, you can specify to use only a part
1962 of this flash sector for the environment. This saves
1963 memory for the RAM copy of the environment.
1965 It may also save flash memory if you decide to use this
1966 when your environment is "embedded" within U-Boot code,
1967 since then the remainder of the flash sector could be used
1968 for U-Boot code. It should be pointed out that this is
1969 STRONGLY DISCOURAGED from a robustness point of view:
1970 updating the environment in flash makes it always
1971 necessary to erase the WHOLE sector. If something goes
1972 wrong before the contents has been restored from a copy in
1973 RAM, your target system will be dead.
1975 - CFG_ENV_ADDR_REDUND
1978 These settings describe a second storage area used to hold
1979 a redundand copy of the environment data, so that there is
1980 a valid backup copy in case there is a power failure during
1981 a "saveenv" operation.
1983 BE CAREFUL! Any changes to the flash layout, and some changes to the
1984 source code will make it necessary to adapt <board>/u-boot.lds*
1988 - CFG_ENV_IS_IN_NVRAM:
1990 Define this if you have some non-volatile memory device
1991 (NVRAM, battery buffered SRAM) which you want to use for the
1997 These two #defines are used to determin the memory area you
1998 want to use for environment. It is assumed that this memory
1999 can just be read and written to, without any special
2002 BE CAREFUL! The first access to the environment happens quite early
2003 in U-Boot initalization (when we try to get the setting of for the
2004 console baudrate). You *MUST* have mappend your NVRAM area then, or
2007 Please note that even with NVRAM we still use a copy of the
2008 environment in RAM: we could work on NVRAM directly, but we want to
2009 keep settings there always unmodified except somebody uses "saveenv"
2010 to save the current settings.
2013 - CFG_ENV_IS_IN_EEPROM:
2015 Use this if you have an EEPROM or similar serial access
2016 device and a driver for it.
2021 These two #defines specify the offset and size of the
2022 environment area within the total memory of your EEPROM.
2024 - CFG_I2C_EEPROM_ADDR:
2025 If defined, specified the chip address of the EEPROM device.
2026 The default address is zero.
2028 - CFG_EEPROM_PAGE_WRITE_BITS:
2029 If defined, the number of bits used to address bytes in a
2030 single page in the EEPROM device. A 64 byte page, for example
2031 would require six bits.
2033 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2034 If defined, the number of milliseconds to delay between
2035 page writes. The default is zero milliseconds.
2037 - CFG_I2C_EEPROM_ADDR_LEN:
2038 The length in bytes of the EEPROM memory array address. Note
2039 that this is NOT the chip address length!
2041 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2042 EEPROM chips that implement "address overflow" are ones
2043 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2044 address and the extra bits end up in the "chip address" bit
2045 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2048 Note that we consider the length of the address field to
2049 still be one byte because the extra address bits are hidden
2050 in the chip address.
2053 The size in bytes of the EEPROM device.
2056 - CFG_ENV_IS_IN_DATAFLASH:
2058 Define this if you have a DataFlash memory device which you
2059 want to use for the environment.
2065 These three #defines specify the offset and size of the
2066 environment area within the total memory of your DataFlash placed
2067 at the specified address.
2069 - CFG_ENV_IS_IN_NAND:
2071 Define this if you have a NAND device which you want to use
2072 for the environment.
2077 These two #defines specify the offset and size of the environment
2078 area within the first NAND device.
2080 - CFG_ENV_OFFSET_REDUND
2082 This setting describes a second storage area of CFG_ENV_SIZE
2083 size used to hold a redundant copy of the environment data,
2084 so that there is a valid backup copy in case there is a
2085 power failure during a "saveenv" operation.
2087 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2088 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2089 the NAND devices block size.
2091 - CFG_SPI_INIT_OFFSET
2093 Defines offset to the initial SPI buffer area in DPRAM. The
2094 area is used at an early stage (ROM part) if the environment
2095 is configured to reside in the SPI EEPROM: We need a 520 byte
2096 scratch DPRAM area. It is used between the two initialization
2097 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2098 to be a good choice since it makes it far enough from the
2099 start of the data area as well as from the stack pointer.
2101 Please note that the environment is read-only as long as the monitor
2102 has been relocated to RAM and a RAM copy of the environment has been
2103 created; also, when using EEPROM you will have to use getenv_r()
2104 until then to read environment variables.
2106 The environment is protected by a CRC32 checksum. Before the monitor
2107 is relocated into RAM, as a result of a bad CRC you will be working
2108 with the compiled-in default environment - *silently*!!! [This is
2109 necessary, because the first environment variable we need is the
2110 "baudrate" setting for the console - if we have a bad CRC, we don't
2111 have any device yet where we could complain.]
2113 Note: once the monitor has been relocated, then it will complain if
2114 the default environment is used; a new CRC is computed as soon as you
2115 use the "saveenv" command to store a valid environment.
2117 - CFG_FAULT_ECHO_LINK_DOWN:
2118 Echo the inverted Ethernet link state to the fault LED.
2120 Note: If this option is active, then CFG_FAULT_MII_ADDR
2121 also needs to be defined.
2123 - CFG_FAULT_MII_ADDR:
2124 MII address of the PHY to check for the Ethernet link state.
2126 - CFG_64BIT_VSPRINTF:
2127 Makes vsprintf (and all *printf functions) support printing
2128 of 64bit values by using the L quantifier
2130 - CFG_64BIT_STRTOUL:
2131 Adds simple_strtoull that returns a 64bit value
2133 Low Level (hardware related) configuration options:
2134 ---------------------------------------------------
2136 - CFG_CACHELINE_SIZE:
2137 Cache Line Size of the CPU.
2140 Default address of the IMMR after system reset.
2142 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2143 and RPXsuper) to be able to adjust the position of
2144 the IMMR register after a reset.
2146 - Floppy Disk Support:
2147 CFG_FDC_DRIVE_NUMBER
2149 the default drive number (default value 0)
2153 defines the spacing between fdc chipset registers
2158 defines the offset of register from address. It
2159 depends on which part of the data bus is connected to
2160 the fdc chipset. (default value 0)
2162 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2163 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2166 if CFG_FDC_HW_INIT is defined, then the function
2167 fdc_hw_init() is called at the beginning of the FDC
2168 setup. fdc_hw_init() must be provided by the board
2169 source code. It is used to make hardware dependant
2172 - CFG_IMMR: Physical address of the Internal Memory.
2173 DO NOT CHANGE unless you know exactly what you're
2174 doing! (11-4) [MPC8xx/82xx systems only]
2176 - CFG_INIT_RAM_ADDR:
2178 Start address of memory area that can be used for
2179 initial data and stack; please note that this must be
2180 writable memory that is working WITHOUT special
2181 initialization, i. e. you CANNOT use normal RAM which
2182 will become available only after programming the
2183 memory controller and running certain initialization
2186 U-Boot uses the following memory types:
2187 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2188 - MPC824X: data cache
2189 - PPC4xx: data cache
2191 - CFG_GBL_DATA_OFFSET:
2193 Offset of the initial data structure in the memory
2194 area defined by CFG_INIT_RAM_ADDR. Usually
2195 CFG_GBL_DATA_OFFSET is chosen such that the initial
2196 data is located at the end of the available space
2197 (sometimes written as (CFG_INIT_RAM_END -
2198 CFG_INIT_DATA_SIZE), and the initial stack is just
2199 below that area (growing from (CFG_INIT_RAM_ADDR +
2200 CFG_GBL_DATA_OFFSET) downward.
2203 On the MPC824X (or other systems that use the data
2204 cache for initial memory) the address chosen for
2205 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2206 point to an otherwise UNUSED address space between
2207 the top of RAM and the start of the PCI space.
2209 - CFG_SIUMCR: SIU Module Configuration (11-6)
2211 - CFG_SYPCR: System Protection Control (11-9)
2213 - CFG_TBSCR: Time Base Status and Control (11-26)
2215 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2217 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2219 - CFG_SCCR: System Clock and reset Control Register (15-27)
2221 - CFG_OR_TIMING_SDRAM:
2225 periodic timer for refresh
2227 - CFG_DER: Debug Event Register (37-47)
2229 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2230 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2231 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2233 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2235 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2236 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2237 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2238 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2240 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2241 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2242 Machine Mode Register and Memory Periodic Timer
2243 Prescaler definitions (SDRAM timing)
2245 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2246 enable I2C microcode relocation patch (MPC8xx);
2247 define relocation offset in DPRAM [DSP2]
2249 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2250 enable SPI microcode relocation patch (MPC8xx);
2251 define relocation offset in DPRAM [SCC4]
2254 Use OSCM clock mode on MBX8xx board. Be careful,
2255 wrong setting might damage your board. Read
2256 doc/README.MBX before setting this variable!
2258 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2259 Offset of the bootmode word in DPRAM used by post
2260 (Power On Self Tests). This definition overrides
2261 #define'd default value in commproc.h resp.
2264 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2265 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2266 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2267 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2268 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2269 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2270 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2271 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2272 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2274 - CONFIG_ETHER_ON_FEC[12]
2275 Define to enable FEC[12] on a 8xx series processor.
2277 - CONFIG_FEC[12]_PHY
2278 Define to the hardcoded PHY address which corresponds
2279 to the given FEC; i. e.
2280 #define CONFIG_FEC1_PHY 4
2281 means that the PHY with address 4 is connected to FEC1
2283 When set to -1, means to probe for first available.
2285 - CONFIG_FEC[12]_PHY_NORXERR
2286 The PHY does not have a RXERR line (RMII only).
2287 (so program the FEC to ignore it).
2290 Enable RMII mode for all FECs.
2291 Note that this is a global option, we can't
2292 have one FEC in standard MII mode and another in RMII mode.
2294 - CONFIG_CRC32_VERIFY
2295 Add a verify option to the crc32 command.
2298 => crc32 -v <address> <count> <crc32>
2300 Where address/count indicate a memory area
2301 and crc32 is the correct crc32 which the
2305 Add the "loopw" memory command. This only takes effect if
2306 the memory commands are activated globally (CFG_CMD_MEM).
2309 Add the "mdc" and "mwc" memory commands. These are cyclic
2314 This command will print 4 bytes (10,11,12,13) each 500 ms.
2316 => mwc.l 100 12345678 10
2317 This command will write 12345678 to address 100 all 10 ms.
2319 This only takes effect if the memory commands are activated
2320 globally (CFG_CMD_MEM).
2322 - CONFIG_SKIP_LOWLEVEL_INIT
2323 - CONFIG_SKIP_RELOCATE_UBOOT
2325 [ARM only] If these variables are defined, then
2326 certain low level initializations (like setting up
2327 the memory controller) are omitted and/or U-Boot does
2328 not relocate itself into RAM.
2329 Normally these variables MUST NOT be defined. The
2330 only exception is when U-Boot is loaded (to RAM) by
2331 some other boot loader or by a debugger which
2332 performs these intializations itself.
2335 Building the Software:
2336 ======================
2338 Building U-Boot has been tested in native PPC environments (on a
2339 PowerBook G3 running LinuxPPC 2000) and in cross environments
2340 (running RedHat 6.x and 7.x Linux on x86, Solaris 2.6 on a SPARC, and
2343 If you are not using a native PPC environment, it is assumed that you
2344 have the GNU cross compiling tools available in your path and named
2345 with a prefix of "powerpc-linux-". If this is not the case, (e.g. if
2346 you are using Monta Vista's Hard Hat Linux CDK 1.2) you must change
2347 the definition of CROSS_COMPILE in Makefile. For HHL on a 4xx CPU,
2350 CROSS_COMPILE = ppc_4xx-
2353 U-Boot is intended to be simple to build. After installing the
2354 sources you must configure U-Boot for one specific board type. This
2359 where "NAME_config" is the name of one of the existing
2360 configurations; the following names are supported:
2362 ADCIOP_config FPS860L_config omap730p2_config
2363 ADS860_config GEN860T_config pcu_e_config
2365 AR405_config GENIETV_config PIP405_config
2366 at91rm9200dk_config GTH_config QS823_config
2367 CANBT_config hermes_config QS850_config
2368 cmi_mpc5xx_config hymod_config QS860T_config
2369 cogent_common_config IP860_config RPXlite_config
2370 cogent_mpc8260_config IVML24_config RPXlite_DW_config
2371 cogent_mpc8xx_config IVMS8_config RPXsuper_config
2372 CPCI405_config JSE_config rsdproto_config
2373 CPCIISER4_config LANTEC_config Sandpoint8240_config
2374 csb272_config lwmon_config sbc8260_config
2375 CU824_config MBX860T_config sbc8560_33_config
2376 DUET_ADS_config MBX_config sbc8560_66_config
2377 EBONY_config MPC8260ADS_config SM850_config
2378 ELPT860_config MPC8540ADS_config SPD823TS_config
2379 ESTEEM192E_config MPC8540EVAL_config stxgp3_config
2380 ETX094_config MPC8560ADS_config SXNI855T_config
2381 FADS823_config NETVIA_config TQM823L_config
2382 FADS850SAR_config omap1510inn_config TQM850L_config
2383 FADS860T_config omap1610h2_config TQM855L_config
2384 FPS850L_config omap1610inn_config TQM860L_config
2385 omap5912osk_config walnut_config
2386 omap2420h4_config Yukon8220_config
2389 Note: for some board special configuration names may exist; check if
2390 additional information is available from the board vendor; for
2391 instance, the TQM823L systems are available without (standard)
2392 or with LCD support. You can select such additional "features"
2393 when chosing the configuration, i. e.
2396 - will configure for a plain TQM823L, i. e. no LCD support
2398 make TQM823L_LCD_config
2399 - will configure for a TQM823L with U-Boot console on LCD
2404 Finally, type "make all", and you should get some working U-Boot
2405 images ready for download to / installation on your system:
2407 - "u-boot.bin" is a raw binary image
2408 - "u-boot" is an image in ELF binary format
2409 - "u-boot.srec" is in Motorola S-Record format
2411 By default the build is performed locally and the objects are saved
2412 in the source directory. One of the two methods can be used to change
2413 this behavior and build U-Boot to some external directory:
2415 1. Add O= to the make command line invocations:
2417 make O=/tmp/build distclean
2418 make O=/tmp/build NAME_config
2419 make O=/tmp/build all
2421 2. Set environment variable BUILD_DIR to point to the desired location:
2423 export BUILD_DIR=/tmp/build
2428 Note that the command line "O=" setting overrides the BUILD_DIR environment
2432 Please be aware that the Makefiles assume you are using GNU make, so
2433 for instance on NetBSD you might need to use "gmake" instead of
2437 If the system board that you have is not listed, then you will need
2438 to port U-Boot to your hardware platform. To do this, follow these
2441 1. Add a new configuration option for your board to the toplevel
2442 "Makefile" and to the "MAKEALL" script, using the existing
2443 entries as examples. Note that here and at many other places
2444 boards and other names are listed in alphabetical sort order. Please
2446 2. Create a new directory to hold your board specific code. Add any
2447 files you need. In your board directory, you will need at least
2448 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2449 3. Create a new configuration file "include/configs/<board>.h" for
2451 3. If you're porting U-Boot to a new CPU, then also create a new
2452 directory to hold your CPU specific code. Add any files you need.
2453 4. Run "make <board>_config" with your new name.
2454 5. Type "make", and you should get a working "u-boot.srec" file
2455 to be installed on your target system.
2456 6. Debug and solve any problems that might arise.
2457 [Of course, this last step is much harder than it sounds.]
2460 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2461 ==============================================================
2463 If you have modified U-Boot sources (for instance added a new board
2464 or support for new devices, a new CPU, etc.) you are expected to
2465 provide feedback to the other developers. The feedback normally takes
2466 the form of a "patch", i. e. a context diff against a certain (latest
2467 official or latest in CVS) version of U-Boot sources.
2469 But before you submit such a patch, please verify that your modifi-
2470 cation did not break existing code. At least make sure that *ALL* of
2471 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2472 just run the "MAKEALL" script, which will configure and build U-Boot
2473 for ALL supported system. Be warned, this will take a while. You can
2474 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2475 environment variable to the script, i. e. to use the cross tools from
2476 MontaVista's Hard Hat Linux you can type
2478 CROSS_COMPILE=ppc_8xx- MAKEALL
2480 or to build on a native PowerPC system you can type
2482 CROSS_COMPILE=' ' MAKEALL
2484 When using the MAKEALL script, the default behaviour is to build U-Boot
2485 in the source directory. This location can be changed by setting the
2486 BUILD_DIR environment variable. Also, for each target built, the MAKEALL
2487 script saves two log files (<target>.ERR and <target>.MAKEALL) in the
2488 <source dir>/LOG directory. This default location can be changed by
2489 setting the MAKEALL_LOGDIR environment variable. For example:
2491 export BUILD_DIR=/tmp/build
2492 export MAKEALL_LOGDIR=/tmp/log
2493 CROSS_COMPILE=ppc_8xx- MAKEALL
2495 With the above settings build objects are saved in the /tmp/build, log
2496 files are saved in the /tmp/log and the source tree remains clean during
2497 the whole build process.
2500 See also "U-Boot Porting Guide" below.
2503 Monitor Commands - Overview:
2504 ============================
2506 go - start application at address 'addr'
2507 run - run commands in an environment variable
2508 bootm - boot application image from memory
2509 bootp - boot image via network using BootP/TFTP protocol
2510 tftpboot- boot image via network using TFTP protocol
2511 and env variables "ipaddr" and "serverip"
2512 (and eventually "gatewayip")
2513 rarpboot- boot image via network using RARP/TFTP protocol
2514 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2515 loads - load S-Record file over serial line
2516 loadb - load binary file over serial line (kermit mode)
2518 mm - memory modify (auto-incrementing)
2519 nm - memory modify (constant address)
2520 mw - memory write (fill)
2522 cmp - memory compare
2523 crc32 - checksum calculation
2524 imd - i2c memory display
2525 imm - i2c memory modify (auto-incrementing)
2526 inm - i2c memory modify (constant address)
2527 imw - i2c memory write (fill)
2528 icrc32 - i2c checksum calculation
2529 iprobe - probe to discover valid I2C chip addresses
2530 iloop - infinite loop on address range
2531 isdram - print SDRAM configuration information
2532 sspi - SPI utility commands
2533 base - print or set address offset
2534 printenv- print environment variables
2535 setenv - set environment variables
2536 saveenv - save environment variables to persistent storage
2537 protect - enable or disable FLASH write protection
2538 erase - erase FLASH memory
2539 flinfo - print FLASH memory information
2540 bdinfo - print Board Info structure
2541 iminfo - print header information for application image
2542 coninfo - print console devices and informations
2543 ide - IDE sub-system
2544 loop - infinite loop on address range
2545 loopw - infinite write loop on address range
2546 mtest - simple RAM test
2547 icache - enable or disable instruction cache
2548 dcache - enable or disable data cache
2549 reset - Perform RESET of the CPU
2550 echo - echo args to console
2551 version - print monitor version
2552 help - print online help
2553 ? - alias for 'help'
2556 Monitor Commands - Detailed Description:
2557 ========================================
2561 For now: just type "help <command>".
2564 Environment Variables:
2565 ======================
2567 U-Boot supports user configuration using Environment Variables which
2568 can be made persistent by saving to Flash memory.
2570 Environment Variables are set using "setenv", printed using
2571 "printenv", and saved to Flash using "saveenv". Using "setenv"
2572 without a value can be used to delete a variable from the
2573 environment. As long as you don't save the environment you are
2574 working with an in-memory copy. In case the Flash area containing the
2575 environment is erased by accident, a default environment is provided.
2577 Some configuration options can be set using Environment Variables:
2579 baudrate - see CONFIG_BAUDRATE
2581 bootdelay - see CONFIG_BOOTDELAY
2583 bootcmd - see CONFIG_BOOTCOMMAND
2585 bootargs - Boot arguments when booting an RTOS image
2587 bootfile - Name of the image to load with TFTP
2589 autoload - if set to "no" (any string beginning with 'n'),
2590 "bootp" will just load perform a lookup of the
2591 configuration from the BOOTP server, but not try to
2592 load any image using TFTP
2594 autostart - if set to "yes", an image loaded using the "bootp",
2595 "rarpboot", "tftpboot" or "diskboot" commands will
2596 be automatically started (by internally calling
2599 If set to "no", a standalone image passed to the
2600 "bootm" command will be copied to the load address
2601 (and eventually uncompressed), but NOT be started.
2602 This can be used to load and uncompress arbitrary
2605 i2cfast - (PPC405GP|PPC405EP only)
2606 if set to 'y' configures Linux I2C driver for fast
2607 mode (400kHZ). This environment variable is used in
2608 initialization code. So, for changes to be effective
2609 it must be saved and board must be reset.
2611 initrd_high - restrict positioning of initrd images:
2612 If this variable is not set, initrd images will be
2613 copied to the highest possible address in RAM; this
2614 is usually what you want since it allows for
2615 maximum initrd size. If for some reason you want to
2616 make sure that the initrd image is loaded below the
2617 CFG_BOOTMAPSZ limit, you can set this environment
2618 variable to a value of "no" or "off" or "0".
2619 Alternatively, you can set it to a maximum upper
2620 address to use (U-Boot will still check that it
2621 does not overwrite the U-Boot stack and data).
2623 For instance, when you have a system with 16 MB
2624 RAM, and want to reserve 4 MB from use by Linux,
2625 you can do this by adding "mem=12M" to the value of
2626 the "bootargs" variable. However, now you must make
2627 sure that the initrd image is placed in the first
2628 12 MB as well - this can be done with
2630 setenv initrd_high 00c00000
2632 If you set initrd_high to 0xFFFFFFFF, this is an
2633 indication to U-Boot that all addresses are legal
2634 for the Linux kernel, including addresses in flash
2635 memory. In this case U-Boot will NOT COPY the
2636 ramdisk at all. This may be useful to reduce the
2637 boot time on your system, but requires that this
2638 feature is supported by your Linux kernel.
2640 ipaddr - IP address; needed for tftpboot command
2642 loadaddr - Default load address for commands like "bootp",
2643 "rarpboot", "tftpboot", "loadb" or "diskboot"
2645 loads_echo - see CONFIG_LOADS_ECHO
2647 serverip - TFTP server IP address; needed for tftpboot command
2649 bootretry - see CONFIG_BOOT_RETRY_TIME
2651 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2653 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2655 ethprime - When CONFIG_NET_MULTI is enabled controls which
2656 interface is used first.
2658 ethact - When CONFIG_NET_MULTI is enabled controls which
2659 interface is currently active. For example you
2660 can do the following
2662 => setenv ethact FEC ETHERNET
2663 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2664 => setenv ethact SCC ETHERNET
2665 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2667 netretry - When set to "no" each network operation will
2668 either succeed or fail without retrying.
2669 When set to "once" the network operation will
2670 fail when all the available network interfaces
2671 are tried once without success.
2672 Useful on scripts which control the retry operation
2675 tftpsrcport - If this is set, the value is used for TFTP's
2678 tftpdstport - If this is set, the value is used for TFTP's UDP
2679 destination port instead of the Well Know Port 69.
2681 vlan - When set to a value < 4095 the traffic over
2682 ethernet is encapsulated/received over 802.1q
2685 The following environment variables may be used and automatically
2686 updated by the network boot commands ("bootp" and "rarpboot"),
2687 depending the information provided by your boot server:
2689 bootfile - see above
2690 dnsip - IP address of your Domain Name Server
2691 dnsip2 - IP address of your secondary Domain Name Server
2692 gatewayip - IP address of the Gateway (Router) to use
2693 hostname - Target hostname
2695 netmask - Subnet Mask
2696 rootpath - Pathname of the root filesystem on the NFS server
2697 serverip - see above
2700 There are two special Environment Variables:
2702 serial# - contains hardware identification information such
2703 as type string and/or serial number
2704 ethaddr - Ethernet address
2706 These variables can be set only once (usually during manufacturing of
2707 the board). U-Boot refuses to delete or overwrite these variables
2708 once they have been set once.
2711 Further special Environment Variables:
2713 ver - Contains the U-Boot version string as printed
2714 with the "version" command. This variable is
2715 readonly (see CONFIG_VERSION_VARIABLE).
2718 Please note that changes to some configuration parameters may take
2719 only effect after the next boot (yes, that's just like Windoze :-).
2722 Command Line Parsing:
2723 =====================
2725 There are two different command line parsers available with U-Boot:
2726 the old "simple" one, and the much more powerful "hush" shell:
2728 Old, simple command line parser:
2729 --------------------------------
2731 - supports environment variables (through setenv / saveenv commands)
2732 - several commands on one line, separated by ';'
2733 - variable substitution using "... ${name} ..." syntax
2734 - special characters ('$', ';') can be escaped by prefixing with '\',
2736 setenv bootcmd bootm \${address}
2737 - You can also escape text by enclosing in single apostrophes, for example:
2738 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2743 - similar to Bourne shell, with control structures like
2744 if...then...else...fi, for...do...done; while...do...done,
2745 until...do...done, ...
2746 - supports environment ("global") variables (through setenv / saveenv
2747 commands) and local shell variables (through standard shell syntax
2748 "name=value"); only environment variables can be used with "run"
2754 (1) If a command line (or an environment variable executed by a "run"
2755 command) contains several commands separated by semicolon, and
2756 one of these commands fails, then the remaining commands will be
2759 (2) If you execute several variables with one call to run (i. e.
2760 calling run with a list af variables as arguments), any failing
2761 command will cause "run" to terminate, i. e. the remaining
2762 variables are not executed.
2764 Note for Redundant Ethernet Interfaces:
2765 =======================================
2767 Some boards come with redundant ethernet interfaces; U-Boot supports
2768 such configurations and is capable of automatic selection of a
2769 "working" interface when needed. MAC assignment works as follows:
2771 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2772 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2773 "eth1addr" (=>eth1), "eth2addr", ...
2775 If the network interface stores some valid MAC address (for instance
2776 in SROM), this is used as default address if there is NO correspon-
2777 ding setting in the environment; if the corresponding environment
2778 variable is set, this overrides the settings in the card; that means:
2780 o If the SROM has a valid MAC address, and there is no address in the
2781 environment, the SROM's address is used.
2783 o If there is no valid address in the SROM, and a definition in the
2784 environment exists, then the value from the environment variable is
2787 o If both the SROM and the environment contain a MAC address, and
2788 both addresses are the same, this MAC address is used.
2790 o If both the SROM and the environment contain a MAC address, and the
2791 addresses differ, the value from the environment is used and a
2794 o If neither SROM nor the environment contain a MAC address, an error
2801 The "boot" commands of this monitor operate on "image" files which
2802 can be basicly anything, preceeded by a special header; see the
2803 definitions in include/image.h for details; basicly, the header
2804 defines the following image properties:
2806 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
2807 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
2808 LynxOS, pSOS, QNX, RTEMS, ARTOS;
2809 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
2810 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
2811 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
2812 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
2813 * Compression Type (uncompressed, gzip, bzip2)
2819 The header is marked by a special Magic Number, and both the header
2820 and the data portions of the image are secured against corruption by
2827 Although U-Boot should support any OS or standalone application
2828 easily, the main focus has always been on Linux during the design of
2831 U-Boot includes many features that so far have been part of some
2832 special "boot loader" code within the Linux kernel. Also, any
2833 "initrd" images to be used are no longer part of one big Linux image;
2834 instead, kernel and "initrd" are separate images. This implementation
2835 serves several purposes:
2837 - the same features can be used for other OS or standalone
2838 applications (for instance: using compressed images to reduce the
2839 Flash memory footprint)
2841 - it becomes much easier to port new Linux kernel versions because
2842 lots of low-level, hardware dependent stuff are done by U-Boot
2844 - the same Linux kernel image can now be used with different "initrd"
2845 images; of course this also means that different kernel images can
2846 be run with the same "initrd". This makes testing easier (you don't
2847 have to build a new "zImage.initrd" Linux image when you just
2848 change a file in your "initrd"). Also, a field-upgrade of the
2849 software is easier now.
2855 Porting Linux to U-Boot based systems:
2856 ---------------------------------------
2858 U-Boot cannot save you from doing all the necessary modifications to
2859 configure the Linux device drivers for use with your target hardware
2860 (no, we don't intend to provide a full virtual machine interface to
2863 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
2865 Just make sure your machine specific header file (for instance
2866 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
2867 Information structure as we define in include/u-boot.h, and make
2868 sure that your definition of IMAP_ADDR uses the same value as your
2869 U-Boot configuration in CFG_IMMR.
2872 Configuring the Linux kernel:
2873 -----------------------------
2875 No specific requirements for U-Boot. Make sure you have some root
2876 device (initial ramdisk, NFS) for your target system.
2879 Building a Linux Image:
2880 -----------------------
2882 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
2883 not used. If you use recent kernel source, a new build target
2884 "uImage" will exist which automatically builds an image usable by
2885 U-Boot. Most older kernels also have support for a "pImage" target,
2886 which was introduced for our predecessor project PPCBoot and uses a
2887 100% compatible format.
2896 The "uImage" build target uses a special tool (in 'tools/mkimage') to
2897 encapsulate a compressed Linux kernel image with header information,
2898 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
2900 * build a standard "vmlinux" kernel image (in ELF binary format):
2902 * convert the kernel into a raw binary image:
2904 ${CROSS_COMPILE}-objcopy -O binary \
2905 -R .note -R .comment \
2906 -S vmlinux linux.bin
2908 * compress the binary image:
2912 * package compressed binary image for U-Boot:
2914 mkimage -A ppc -O linux -T kernel -C gzip \
2915 -a 0 -e 0 -n "Linux Kernel Image" \
2916 -d linux.bin.gz uImage
2919 The "mkimage" tool can also be used to create ramdisk images for use
2920 with U-Boot, either separated from the Linux kernel image, or
2921 combined into one file. "mkimage" encapsulates the images with a 64
2922 byte header containing information about target architecture,
2923 operating system, image type, compression method, entry points, time
2924 stamp, CRC32 checksums, etc.
2926 "mkimage" can be called in two ways: to verify existing images and
2927 print the header information, or to build new images.
2929 In the first form (with "-l" option) mkimage lists the information
2930 contained in the header of an existing U-Boot image; this includes
2931 checksum verification:
2933 tools/mkimage -l image
2934 -l ==> list image header information
2936 The second form (with "-d" option) is used to build a U-Boot image
2937 from a "data file" which is used as image payload:
2939 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
2940 -n name -d data_file image
2941 -A ==> set architecture to 'arch'
2942 -O ==> set operating system to 'os'
2943 -T ==> set image type to 'type'
2944 -C ==> set compression type 'comp'
2945 -a ==> set load address to 'addr' (hex)
2946 -e ==> set entry point to 'ep' (hex)
2947 -n ==> set image name to 'name'
2948 -d ==> use image data from 'datafile'
2950 Right now, all Linux kernels for PowerPC systems use the same load
2951 address (0x00000000), but the entry point address depends on the
2954 - 2.2.x kernels have the entry point at 0x0000000C,
2955 - 2.3.x and later kernels have the entry point at 0x00000000.
2957 So a typical call to build a U-Boot image would read:
2959 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2960 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
2961 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
2962 > examples/uImage.TQM850L
2963 Image Name: 2.4.4 kernel for TQM850L
2964 Created: Wed Jul 19 02:34:59 2000
2965 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2966 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2967 Load Address: 0x00000000
2968 Entry Point: 0x00000000
2970 To verify the contents of the image (or check for corruption):
2972 -> tools/mkimage -l examples/uImage.TQM850L
2973 Image Name: 2.4.4 kernel for TQM850L
2974 Created: Wed Jul 19 02:34:59 2000
2975 Image Type: PowerPC Linux Kernel Image (gzip compressed)
2976 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
2977 Load Address: 0x00000000
2978 Entry Point: 0x00000000
2980 NOTE: for embedded systems where boot time is critical you can trade
2981 speed for memory and install an UNCOMPRESSED image instead: this
2982 needs more space in Flash, but boots much faster since it does not
2983 need to be uncompressed:
2985 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
2986 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
2987 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
2988 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
2989 > examples/uImage.TQM850L-uncompressed
2990 Image Name: 2.4.4 kernel for TQM850L
2991 Created: Wed Jul 19 02:34:59 2000
2992 Image Type: PowerPC Linux Kernel Image (uncompressed)
2993 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
2994 Load Address: 0x00000000
2995 Entry Point: 0x00000000
2998 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
2999 when your kernel is intended to use an initial ramdisk:
3001 -> tools/mkimage -n 'Simple Ramdisk Image' \
3002 > -A ppc -O linux -T ramdisk -C gzip \
3003 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3004 Image Name: Simple Ramdisk Image
3005 Created: Wed Jan 12 14:01:50 2000
3006 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3007 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3008 Load Address: 0x00000000
3009 Entry Point: 0x00000000
3012 Installing a Linux Image:
3013 -------------------------
3015 To downloading a U-Boot image over the serial (console) interface,
3016 you must convert the image to S-Record format:
3018 objcopy -I binary -O srec examples/image examples/image.srec
3020 The 'objcopy' does not understand the information in the U-Boot
3021 image header, so the resulting S-Record file will be relative to
3022 address 0x00000000. To load it to a given address, you need to
3023 specify the target address as 'offset' parameter with the 'loads'
3026 Example: install the image to address 0x40100000 (which on the
3027 TQM8xxL is in the first Flash bank):
3029 => erase 40100000 401FFFFF
3035 ## Ready for S-Record download ...
3036 ~>examples/image.srec
3037 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3039 15989 15990 15991 15992
3040 [file transfer complete]
3042 ## Start Addr = 0x00000000
3045 You can check the success of the download using the 'iminfo' command;
3046 this includes a checksum verification so you can be sure no data
3047 corruption happened:
3051 ## Checking Image at 40100000 ...
3052 Image Name: 2.2.13 for initrd on TQM850L
3053 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3054 Data Size: 335725 Bytes = 327 kB = 0 MB
3055 Load Address: 00000000
3056 Entry Point: 0000000c
3057 Verifying Checksum ... OK
3063 The "bootm" command is used to boot an application that is stored in
3064 memory (RAM or Flash). In case of a Linux kernel image, the contents
3065 of the "bootargs" environment variable is passed to the kernel as
3066 parameters. You can check and modify this variable using the
3067 "printenv" and "setenv" commands:
3070 => printenv bootargs
3071 bootargs=root=/dev/ram
3073 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3075 => printenv bootargs
3076 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3079 ## Booting Linux kernel at 40020000 ...
3080 Image Name: 2.2.13 for NFS on TQM850L
3081 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3082 Data Size: 381681 Bytes = 372 kB = 0 MB
3083 Load Address: 00000000
3084 Entry Point: 0000000c
3085 Verifying Checksum ... OK
3086 Uncompressing Kernel Image ... OK
3087 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
3088 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3089 time_init: decrementer frequency = 187500000/60
3090 Calibrating delay loop... 49.77 BogoMIPS
3091 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3094 If you want to boot a Linux kernel with initial ram disk, you pass
3095 the memory addresses of both the kernel and the initrd image (PPBCOOT
3096 format!) to the "bootm" command:
3098 => imi 40100000 40200000
3100 ## Checking Image at 40100000 ...
3101 Image Name: 2.2.13 for initrd on TQM850L
3102 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3103 Data Size: 335725 Bytes = 327 kB = 0 MB
3104 Load Address: 00000000
3105 Entry Point: 0000000c
3106 Verifying Checksum ... OK
3108 ## Checking Image at 40200000 ...
3109 Image Name: Simple Ramdisk Image
3110 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3111 Data Size: 566530 Bytes = 553 kB = 0 MB
3112 Load Address: 00000000
3113 Entry Point: 00000000
3114 Verifying Checksum ... OK
3116 => bootm 40100000 40200000
3117 ## Booting Linux kernel at 40100000 ...
3118 Image Name: 2.2.13 for initrd on TQM850L
3119 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3120 Data Size: 335725 Bytes = 327 kB = 0 MB
3121 Load Address: 00000000
3122 Entry Point: 0000000c
3123 Verifying Checksum ... OK
3124 Uncompressing Kernel Image ... OK
3125 ## Loading RAMDisk Image at 40200000 ...
3126 Image Name: Simple Ramdisk Image
3127 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3128 Data Size: 566530 Bytes = 553 kB = 0 MB
3129 Load Address: 00000000
3130 Entry Point: 00000000
3131 Verifying Checksum ... OK
3132 Loading Ramdisk ... OK
3133 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
3134 Boot arguments: root=/dev/ram
3135 time_init: decrementer frequency = 187500000/60
3136 Calibrating delay loop... 49.77 BogoMIPS
3138 RAMDISK: Compressed image found at block 0
3139 VFS: Mounted root (ext2 filesystem).
3143 Boot Linux and pass a flat device tree:
3146 First, U-Boot must be compiled with the appropriate defines. See the section
3147 titled "Linux Kernel Interface" above for a more in depth explanation. The
3148 following is an example of how to start a kernel and pass an updated
3154 oft=oftrees/mpc8540ads.dtb
3155 => tftp $oftaddr $oft
3156 Speed: 1000, full duplex
3158 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3159 Filename 'oftrees/mpc8540ads.dtb'.
3160 Load address: 0x300000
3163 Bytes transferred = 4106 (100a hex)
3164 => tftp $loadaddr $bootfile
3165 Speed: 1000, full duplex
3167 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3169 Load address: 0x200000
3170 Loading:############
3172 Bytes transferred = 1029407 (fb51f hex)
3177 => bootm $loadaddr - $oftaddr
3178 ## Booting image at 00200000 ...
3179 Image Name: Linux-2.6.17-dirty
3180 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3181 Data Size: 1029343 Bytes = 1005.2 kB
3182 Load Address: 00000000
3183 Entry Point: 00000000
3184 Verifying Checksum ... OK
3185 Uncompressing Kernel Image ... OK
3186 Booting using flat device tree at 0x300000
3187 Using MPC85xx ADS machine description
3188 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3192 More About U-Boot Image Types:
3193 ------------------------------
3195 U-Boot supports the following image types:
3197 "Standalone Programs" are directly runnable in the environment
3198 provided by U-Boot; it is expected that (if they behave
3199 well) you can continue to work in U-Boot after return from
3200 the Standalone Program.
3201 "OS Kernel Images" are usually images of some Embedded OS which
3202 will take over control completely. Usually these programs
3203 will install their own set of exception handlers, device
3204 drivers, set up the MMU, etc. - this means, that you cannot
3205 expect to re-enter U-Boot except by resetting the CPU.
3206 "RAMDisk Images" are more or less just data blocks, and their
3207 parameters (address, size) are passed to an OS kernel that is
3209 "Multi-File Images" contain several images, typically an OS
3210 (Linux) kernel image and one or more data images like
3211 RAMDisks. This construct is useful for instance when you want
3212 to boot over the network using BOOTP etc., where the boot
3213 server provides just a single image file, but you want to get
3214 for instance an OS kernel and a RAMDisk image.
3216 "Multi-File Images" start with a list of image sizes, each
3217 image size (in bytes) specified by an "uint32_t" in network
3218 byte order. This list is terminated by an "(uint32_t)0".
3219 Immediately after the terminating 0 follow the images, one by
3220 one, all aligned on "uint32_t" boundaries (size rounded up to
3221 a multiple of 4 bytes).
3223 "Firmware Images" are binary images containing firmware (like
3224 U-Boot or FPGA images) which usually will be programmed to
3227 "Script files" are command sequences that will be executed by
3228 U-Boot's command interpreter; this feature is especially
3229 useful when you configure U-Boot to use a real shell (hush)
3230 as command interpreter.
3236 One of the features of U-Boot is that you can dynamically load and
3237 run "standalone" applications, which can use some resources of
3238 U-Boot like console I/O functions or interrupt services.
3240 Two simple examples are included with the sources:
3245 'examples/hello_world.c' contains a small "Hello World" Demo
3246 application; it is automatically compiled when you build U-Boot.
3247 It's configured to run at address 0x00040004, so you can play with it
3251 ## Ready for S-Record download ...
3252 ~>examples/hello_world.srec
3253 1 2 3 4 5 6 7 8 9 10 11 ...
3254 [file transfer complete]
3256 ## Start Addr = 0x00040004
3258 => go 40004 Hello World! This is a test.
3259 ## Starting application at 0x00040004 ...
3270 Hit any key to exit ...
3272 ## Application terminated, rc = 0x0
3274 Another example, which demonstrates how to register a CPM interrupt
3275 handler with the U-Boot code, can be found in 'examples/timer.c'.
3276 Here, a CPM timer is set up to generate an interrupt every second.
3277 The interrupt service routine is trivial, just printing a '.'
3278 character, but this is just a demo program. The application can be
3279 controlled by the following keys:
3281 ? - print current values og the CPM Timer registers
3282 b - enable interrupts and start timer
3283 e - stop timer and disable interrupts
3284 q - quit application
3287 ## Ready for S-Record download ...
3288 ~>examples/timer.srec
3289 1 2 3 4 5 6 7 8 9 10 11 ...
3290 [file transfer complete]
3292 ## Start Addr = 0x00040004
3295 ## Starting application at 0x00040004 ...
3298 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3301 [q, b, e, ?] Set interval 1000000 us
3304 [q, b, e, ?] ........
3305 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3308 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3311 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3314 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3316 [q, b, e, ?] ...Stopping timer
3318 [q, b, e, ?] ## Application terminated, rc = 0x0
3324 Over time, many people have reported problems when trying to use the
3325 "minicom" terminal emulation program for serial download. I (wd)
3326 consider minicom to be broken, and recommend not to use it. Under
3327 Unix, I recommend to use C-Kermit for general purpose use (and
3328 especially for kermit binary protocol download ("loadb" command), and
3329 use "cu" for S-Record download ("loads" command).
3331 Nevertheless, if you absolutely want to use it try adding this
3332 configuration to your "File transfer protocols" section:
3334 Name Program Name U/D FullScr IO-Red. Multi
3335 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3336 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3342 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3343 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3345 Building requires a cross environment; it is known to work on
3346 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3347 need gmake since the Makefiles are not compatible with BSD make).
3348 Note that the cross-powerpc package does not install include files;
3349 attempting to build U-Boot will fail because <machine/ansi.h> is
3350 missing. This file has to be installed and patched manually:
3352 # cd /usr/pkg/cross/powerpc-netbsd/include
3354 # ln -s powerpc machine
3355 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3356 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3358 Native builds *don't* work due to incompatibilities between native
3359 and U-Boot include files.
3361 Booting assumes that (the first part of) the image booted is a
3362 stage-2 loader which in turn loads and then invokes the kernel
3363 proper. Loader sources will eventually appear in the NetBSD source
3364 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3365 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3368 Implementation Internals:
3369 =========================
3371 The following is not intended to be a complete description of every
3372 implementation detail. However, it should help to understand the
3373 inner workings of U-Boot and make it easier to port it to custom
3377 Initial Stack, Global Data:
3378 ---------------------------
3380 The implementation of U-Boot is complicated by the fact that U-Boot
3381 starts running out of ROM (flash memory), usually without access to
3382 system RAM (because the memory controller is not initialized yet).
3383 This means that we don't have writable Data or BSS segments, and BSS
3384 is not initialized as zero. To be able to get a C environment working
3385 at all, we have to allocate at least a minimal stack. Implementation
3386 options for this are defined and restricted by the CPU used: Some CPU
3387 models provide on-chip memory (like the IMMR area on MPC8xx and
3388 MPC826x processors), on others (parts of) the data cache can be
3389 locked as (mis-) used as memory, etc.
3391 Chris Hallinan posted a good summary of these issues to the
3392 u-boot-users mailing list:
3394 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3395 From: "Chris Hallinan" <clh@net1plus.com>
3396 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3399 Correct me if I'm wrong, folks, but the way I understand it
3400 is this: Using DCACHE as initial RAM for Stack, etc, does not
3401 require any physical RAM backing up the cache. The cleverness
3402 is that the cache is being used as a temporary supply of
3403 necessary storage before the SDRAM controller is setup. It's
3404 beyond the scope of this list to expain the details, but you
3405 can see how this works by studying the cache architecture and
3406 operation in the architecture and processor-specific manuals.
3408 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3409 is another option for the system designer to use as an
3410 initial stack/ram area prior to SDRAM being available. Either
3411 option should work for you. Using CS 4 should be fine if your
3412 board designers haven't used it for something that would
3413 cause you grief during the initial boot! It is frequently not
3416 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3417 with your processor/board/system design. The default value
3418 you will find in any recent u-boot distribution in
3419 walnut.h should work for you. I'd set it to a value larger
3420 than your SDRAM module. If you have a 64MB SDRAM module, set
3421 it above 400_0000. Just make sure your board has no resources
3422 that are supposed to respond to that address! That code in
3423 start.S has been around a while and should work as is when
3424 you get the config right.
3429 It is essential to remember this, since it has some impact on the C
3430 code for the initialization procedures:
3432 * Initialized global data (data segment) is read-only. Do not attempt
3435 * Do not use any unitialized global data (or implicitely initialized
3436 as zero data - BSS segment) at all - this is undefined, initiali-
3437 zation is performed later (when relocating to RAM).
3439 * Stack space is very limited. Avoid big data buffers or things like
3442 Having only the stack as writable memory limits means we cannot use
3443 normal global data to share information beween the code. But it
3444 turned out that the implementation of U-Boot can be greatly
3445 simplified by making a global data structure (gd_t) available to all
3446 functions. We could pass a pointer to this data as argument to _all_
3447 functions, but this would bloat the code. Instead we use a feature of
3448 the GCC compiler (Global Register Variables) to share the data: we
3449 place a pointer (gd) to the global data into a register which we
3450 reserve for this purpose.
3452 When choosing a register for such a purpose we are restricted by the
3453 relevant (E)ABI specifications for the current architecture, and by
3454 GCC's implementation.
3456 For PowerPC, the following registers have specific use:
3459 R3-R4: parameter passing and return values
3460 R5-R10: parameter passing
3461 R13: small data area pointer
3465 (U-Boot also uses R14 as internal GOT pointer.)
3467 ==> U-Boot will use R29 to hold a pointer to the global data
3469 Note: on PPC, we could use a static initializer (since the
3470 address of the global data structure is known at compile time),
3471 but it turned out that reserving a register results in somewhat
3472 smaller code - although the code savings are not that big (on
3473 average for all boards 752 bytes for the whole U-Boot image,
3474 624 text + 127 data).
3476 On ARM, the following registers are used:
3478 R0: function argument word/integer result
3479 R1-R3: function argument word
3481 R10: stack limit (used only if stack checking if enabled)
3482 R11: argument (frame) pointer
3483 R12: temporary workspace
3486 R15: program counter
3488 ==> U-Boot will use R8 to hold a pointer to the global data
3490 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3491 or current versions of GCC may "optimize" the code too much.
3496 U-Boot runs in system state and uses physical addresses, i.e. the
3497 MMU is not used either for address mapping nor for memory protection.
3499 The available memory is mapped to fixed addresses using the memory
3500 controller. In this process, a contiguous block is formed for each
3501 memory type (Flash, SDRAM, SRAM), even when it consists of several
3502 physical memory banks.
3504 U-Boot is installed in the first 128 kB of the first Flash bank (on
3505 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3506 booting and sizing and initializing DRAM, the code relocates itself
3507 to the upper end of DRAM. Immediately below the U-Boot code some
3508 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3509 configuration setting]. Below that, a structure with global Board
3510 Info data is placed, followed by the stack (growing downward).
3512 Additionally, some exception handler code is copied to the low 8 kB
3513 of DRAM (0x00000000 ... 0x00001FFF).
3515 So a typical memory configuration with 16 MB of DRAM could look like
3518 0x0000 0000 Exception Vector code
3521 0x0000 2000 Free for Application Use
3527 0x00FB FF20 Monitor Stack (Growing downward)
3528 0x00FB FFAC Board Info Data and permanent copy of global data
3529 0x00FC 0000 Malloc Arena
3532 0x00FE 0000 RAM Copy of Monitor Code
3533 ... eventually: LCD or video framebuffer
3534 ... eventually: pRAM (Protected RAM - unchanged by reset)
3535 0x00FF FFFF [End of RAM]
3538 System Initialization:
3539 ----------------------
3541 In the reset configuration, U-Boot starts at the reset entry point
3542 (on most PowerPC systens at address 0x00000100). Because of the reset
3543 configuration for CS0# this is a mirror of the onboard Flash memory.
3544 To be able to re-map memory U-Boot then jumps to its link address.
3545 To be able to implement the initialization code in C, a (small!)
3546 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3547 which provide such a feature like MPC8xx or MPC8260), or in a locked
3548 part of the data cache. After that, U-Boot initializes the CPU core,
3549 the caches and the SIU.
3551 Next, all (potentially) available memory banks are mapped using a
3552 preliminary mapping. For example, we put them on 512 MB boundaries
3553 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3554 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3555 programmed for SDRAM access. Using the temporary configuration, a
3556 simple memory test is run that determines the size of the SDRAM
3559 When there is more than one SDRAM bank, and the banks are of
3560 different size, the largest is mapped first. For equal size, the first
3561 bank (CS2#) is mapped first. The first mapping is always for address
3562 0x00000000, with any additional banks following immediately to create
3563 contiguous memory starting from 0.
3565 Then, the monitor installs itself at the upper end of the SDRAM area
3566 and allocates memory for use by malloc() and for the global Board
3567 Info data; also, the exception vector code is copied to the low RAM
3568 pages, and the final stack is set up.
3570 Only after this relocation will you have a "normal" C environment;
3571 until that you are restricted in several ways, mostly because you are
3572 running from ROM, and because the code will have to be relocated to a
3576 U-Boot Porting Guide:
3577 ----------------------
3579 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3583 int main (int argc, char *argv[])
3585 sighandler_t no_more_time;
3587 signal (SIGALRM, no_more_time);
3588 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3590 if (available_money > available_manpower) {
3591 pay consultant to port U-Boot;
3595 Download latest U-Boot source;
3597 Subscribe to u-boot-users mailing list;
3600 email ("Hi, I am new to U-Boot, how do I get started?");
3604 Read the README file in the top level directory;
3605 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3606 Read the source, Luke;
3609 if (available_money > toLocalCurrency ($2500)) {
3612 Add a lot of aggravation and time;
3615 Create your own board support subdirectory;
3617 Create your own board config file;
3621 Add / modify source code;
3625 email ("Hi, I am having problems...");
3627 Send patch file to Wolfgang;
3632 void no_more_time (int sig)
3641 All contributions to U-Boot should conform to the Linux kernel
3642 coding style; see the file "Documentation/CodingStyle" and the script
3643 "scripts/Lindent" in your Linux kernel source directory. In sources
3644 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3645 spaces before parameters to function calls) is actually used.
3647 Source files originating from a different project (for example the
3648 MTD subsystem) are generally exempt from these guidelines and are not
3649 reformated to ease subsequent migration to newer versions of those
3652 Please note that U-Boot is implemented in C (and to some small parts in
3653 Assembler); no C++ is used, so please do not use C++ style comments (//)
3656 Please also stick to the following formatting rules:
3657 - remove any trailing white space
3658 - use TAB characters for indentation, not spaces
3659 - make sure NOT to use DOS '\r\n' line feeds
3660 - do not add more than 2 empty lines to source files
3661 - do not add trailing empty lines to source files
3663 Submissions which do not conform to the standards may be returned
3664 with a request to reformat the changes.
3670 Since the number of patches for U-Boot is growing, we need to
3671 establish some rules. Submissions which do not conform to these rules
3672 may be rejected, even when they contain important and valuable stuff.
3674 Patches shall be sent to the u-boot-users mailing list.
3676 When you send a patch, please include the following information with
3679 * For bug fixes: a description of the bug and how your patch fixes
3680 this bug. Please try to include a way of demonstrating that the
3681 patch actually fixes something.
3683 * For new features: a description of the feature and your
3686 * A CHANGELOG entry as plaintext (separate from the patch)
3688 * For major contributions, your entry to the CREDITS file
3690 * When you add support for a new board, don't forget to add this
3691 board to the MAKEALL script, too.
3693 * If your patch adds new configuration options, don't forget to
3694 document these in the README file.
3696 * The patch itself. If you are accessing the CVS repository use "cvs
3697 update; cvs diff -puRN"; else, use "diff -purN OLD NEW". If your
3698 version of diff does not support these options, then get the latest
3699 version of GNU diff.
3701 The current directory when running this command shall be the top
3702 level directory of the U-Boot source tree, or it's parent directory
3703 (i. e. please make sure that your patch includes sufficient
3704 directory information for the affected files).
3706 We accept patches as plain text, MIME attachments or as uuencoded
3709 * If one logical set of modifications affects or creates several
3710 files, all these changes shall be submitted in a SINGLE patch file.
3712 * Changesets that contain different, unrelated modifications shall be
3713 submitted as SEPARATE patches, one patch per changeset.
3718 * Before sending the patch, run the MAKEALL script on your patched
3719 source tree and make sure that no errors or warnings are reported
3720 for any of the boards.
3722 * Keep your modifications to the necessary minimum: A patch
3723 containing several unrelated changes or arbitrary reformats will be
3724 returned with a request to re-formatting / split it.
3726 * If you modify existing code, make sure that your new code does not
3727 add to the memory footprint of the code ;-) Small is beautiful!
3728 When adding new features, these should compile conditionally only
3729 (using #ifdef), and the resulting code with the new feature
3730 disabled must not need more memory than the old code without your
3733 * Remember that there is a size limit of 40 kB per message on the
3734 u-boot-users mailing list. Compression may help.
projects / oweals / u-boot.git / blob