2 # (C) Copyright 2000 - 2009
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. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot@lists.denx.de>. There is also an archive of previous traffic
64 on the mailing list - please search the archive before asking FAQ's.
65 Please see http://lists.denx.de/pipermail/u-boot and
66 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Official releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/U-Boot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 /arch Architecture specific files
142 /arm Files generic to ARM architecture
143 /cpu CPU specific files
144 /arm720t Files specific to ARM 720 CPUs
145 /arm920t Files specific to ARM 920 CPUs
146 /at91rm9200 Files specific to Atmel AT91RM9200 CPU
147 /imx Files specific to Freescale MC9328 i.MX CPUs
148 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
149 /arm925t Files specific to ARM 925 CPUs
150 /arm926ejs Files specific to ARM 926 CPUs
151 /arm1136 Files specific to ARM 1136 CPUs
152 /ixp Files specific to Intel XScale IXP CPUs
153 /pxa Files specific to Intel XScale PXA CPUs
154 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
155 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
156 /lib Architecture specific library files
157 /avr32 Files generic to AVR32 architecture
158 /cpu CPU specific files
159 /lib Architecture specific library files
160 /blackfin Files generic to Analog Devices Blackfin architecture
161 /cpu CPU specific files
162 /lib Architecture specific library files
163 /i386 Files generic to i386 architecture
164 /cpu CPU specific files
165 /lib Architecture specific library files
166 /m68k Files generic to m68k architecture
167 /cpu CPU specific files
168 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
169 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
170 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
171 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
172 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
173 /lib Architecture specific library files
174 /microblaze Files generic to microblaze architecture
175 /cpu CPU specific files
176 /lib Architecture specific library files
177 /mips Files generic to MIPS architecture
178 /cpu CPU specific files
179 /lib Architecture specific library files
180 /nios Files generic to Altera NIOS architecture
181 /cpu CPU specific files
182 /lib Architecture specific library files
183 /nios2 Files generic to Altera NIOS2 architecture
184 /cpu CPU specific files
185 /lib Architecture specific library files
186 /powerpc Files generic to PowerPC architecture
187 /cpu CPU specific files
188 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
189 /mpc5xx Files specific to Freescale MPC5xx CPUs
190 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
191 /mpc8xx Files specific to Freescale MPC8xx CPUs
192 /mpc8220 Files specific to Freescale MPC8220 CPUs
193 /mpc824x Files specific to Freescale MPC824x CPUs
194 /mpc8260 Files specific to Freescale MPC8260 CPUs
195 /mpc85xx Files specific to Freescale MPC85xx CPUs
196 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
197 /lib Architecture specific library files
198 /sh Files generic to SH architecture
199 /cpu CPU specific files
200 /sh2 Files specific to sh2 CPUs
201 /sh3 Files specific to sh3 CPUs
202 /sh4 Files specific to sh4 CPUs
203 /lib Architecture specific library files
204 /sparc Files generic to SPARC architecture
205 /cpu CPU specific files
206 /leon2 Files specific to Gaisler LEON2 SPARC CPU
207 /leon3 Files specific to Gaisler LEON3 SPARC CPU
208 /lib Architecture specific library files
209 /api Machine/arch independent API for external apps
210 /board Board dependent files
211 /common Misc architecture independent functions
212 /disk Code for disk drive partition handling
213 /doc Documentation (don't expect too much)
214 /drivers Commonly used device drivers
215 /examples Example code for standalone applications, etc.
216 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
217 /include Header Files
218 /lib Files generic to all architectures
219 /libfdt Library files to support flattened device trees
220 /lzma Library files to support LZMA decompression
221 /lzo Library files to support LZO decompression
223 /post Power On Self Test
224 /rtc Real Time Clock drivers
225 /tools Tools to build S-Record or U-Boot images, etc.
227 Software Configuration:
228 =======================
230 Configuration is usually done using C preprocessor defines; the
231 rationale behind that is to avoid dead code whenever possible.
233 There are two classes of configuration variables:
235 * Configuration _OPTIONS_:
236 These are selectable by the user and have names beginning with
239 * Configuration _SETTINGS_:
240 These depend on the hardware etc. and should not be meddled with if
241 you don't know what you're doing; they have names beginning with
244 Later we will add a configuration tool - probably similar to or even
245 identical to what's used for the Linux kernel. Right now, we have to
246 do the configuration by hand, which means creating some symbolic
247 links and editing some configuration files. We use the TQM8xxL boards
251 Selection of Processor Architecture and Board Type:
252 ---------------------------------------------------
254 For all supported boards there are ready-to-use default
255 configurations available; just type "make <board_name>_config".
257 Example: For a TQM823L module type:
262 For the Cogent platform, you need to specify the CPU type as well;
263 e.g. "make cogent_mpc8xx_config". And also configure the cogent
264 directory according to the instructions in cogent/README.
267 Configuration Options:
268 ----------------------
270 Configuration depends on the combination of board and CPU type; all
271 such information is kept in a configuration file
272 "include/configs/<board_name>.h".
274 Example: For a TQM823L module, all configuration settings are in
275 "include/configs/TQM823L.h".
278 Many of the options are named exactly as the corresponding Linux
279 kernel configuration options. The intention is to make it easier to
280 build a config tool - later.
283 The following options need to be configured:
285 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
287 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
289 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
290 Define exactly one, e.g. CONFIG_ATSTK1002
292 - CPU Module Type: (if CONFIG_COGENT is defined)
293 Define exactly one of
295 --- FIXME --- not tested yet:
296 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
297 CONFIG_CMA287_23, CONFIG_CMA287_50
299 - Motherboard Type: (if CONFIG_COGENT is defined)
300 Define exactly one of
301 CONFIG_CMA101, CONFIG_CMA102
303 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
304 Define one or more of
307 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
308 Define one or more of
309 CONFIG_LCD_HEARTBEAT - update a character position on
310 the LCD display every second with
313 - Board flavour: (if CONFIG_MPC8260ADS is defined)
316 CONFIG_SYS_8260ADS - original MPC8260ADS
317 CONFIG_SYS_8266ADS - MPC8266ADS
318 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
319 CONFIG_SYS_8272ADS - MPC8272ADS
321 - MPC824X Family Member (if CONFIG_MPC824X is defined)
322 Define exactly one of
323 CONFIG_MPC8240, CONFIG_MPC8245
325 - 8xx CPU Options: (if using an MPC8xx CPU)
326 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
327 get_gclk_freq() cannot work
328 e.g. if there is no 32KHz
329 reference PIT/RTC clock
330 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
333 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
334 CONFIG_SYS_8xx_CPUCLK_MIN
335 CONFIG_SYS_8xx_CPUCLK_MAX
336 CONFIG_8xx_CPUCLK_DEFAULT
337 See doc/README.MPC866
339 CONFIG_SYS_MEASURE_CPUCLK
341 Define this to measure the actual CPU clock instead
342 of relying on the correctness of the configured
343 values. Mostly useful for board bringup to make sure
344 the PLL is locked at the intended frequency. Note
345 that this requires a (stable) reference clock (32 kHz
346 RTC clock or CONFIG_SYS_8XX_XIN)
348 CONFIG_SYS_DELAYED_ICACHE
350 Define this option if you want to enable the
351 ICache only when Code runs from RAM.
353 - Intel Monahans options:
354 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
356 Defines the Monahans run mode to oscillator
357 ratio. Valid values are 8, 16, 24, 31. The core
358 frequency is this value multiplied by 13 MHz.
360 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
362 Defines the Monahans turbo mode to oscillator
363 ratio. Valid values are 1 (default if undefined) and
364 2. The core frequency as calculated above is multiplied
367 - Linux Kernel Interface:
370 U-Boot stores all clock information in Hz
371 internally. For binary compatibility with older Linux
372 kernels (which expect the clocks passed in the
373 bd_info data to be in MHz) the environment variable
374 "clocks_in_mhz" can be defined so that U-Boot
375 converts clock data to MHZ before passing it to the
377 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
378 "clocks_in_mhz=1" is automatically included in the
381 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
383 When transferring memsize parameter to linux, some versions
384 expect it to be in bytes, others in MB.
385 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
389 New kernel versions are expecting firmware settings to be
390 passed using flattened device trees (based on open firmware
394 * New libfdt-based support
395 * Adds the "fdt" command
396 * The bootm command automatically updates the fdt
398 OF_CPU - The proper name of the cpus node (only required for
399 MPC512X and MPC5xxx based boards).
400 OF_SOC - The proper name of the soc node (only required for
401 MPC512X and MPC5xxx based boards).
402 OF_TBCLK - The timebase frequency.
403 OF_STDOUT_PATH - The path to the console device
405 boards with QUICC Engines require OF_QE to set UCC MAC
408 CONFIG_OF_BOARD_SETUP
410 Board code has addition modification that it wants to make
411 to the flat device tree before handing it off to the kernel
415 This define fills in the correct boot CPU in the boot
416 param header, the default value is zero if undefined.
420 U-Boot can detect if an IDE device is present or not.
421 If not, and this new config option is activated, U-Boot
422 removes the ATA node from the DTS before booting Linux,
423 so the Linux IDE driver does not probe the device and
424 crash. This is needed for buggy hardware (uc101) where
425 no pull down resistor is connected to the signal IDE5V_DD7.
427 - vxWorks boot parameters:
429 bootvx constructs a valid bootline using the following
430 environments variables: bootfile, ipaddr, serverip, hostname.
431 It loads the vxWorks image pointed bootfile.
433 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
434 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
435 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
436 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
438 CONFIG_SYS_VXWORKS_ADD_PARAMS
440 Add it at the end of the bootline. E.g "u=username pw=secret"
442 Note: If a "bootargs" environment is defined, it will overwride
443 the defaults discussed just above.
448 Define this if you want support for Amba PrimeCell PL010 UARTs.
452 Define this if you want support for Amba PrimeCell PL011 UARTs.
456 If you have Amba PrimeCell PL011 UARTs, set this variable to
457 the clock speed of the UARTs.
461 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
462 define this to a list of base addresses for each (supported)
463 port. See e.g. include/configs/versatile.h
467 Depending on board, define exactly one serial port
468 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
469 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
470 console by defining CONFIG_8xx_CONS_NONE
472 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
473 port routines must be defined elsewhere
474 (i.e. serial_init(), serial_getc(), ...)
477 Enables console device for a color framebuffer. Needs following
478 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
479 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
481 VIDEO_HW_RECTFILL graphic chip supports
484 VIDEO_HW_BITBLT graphic chip supports
485 bit-blit (cf. smiLynxEM)
486 VIDEO_VISIBLE_COLS visible pixel columns
488 VIDEO_VISIBLE_ROWS visible pixel rows
489 VIDEO_PIXEL_SIZE bytes per pixel
490 VIDEO_DATA_FORMAT graphic data format
491 (0-5, cf. cfb_console.c)
492 VIDEO_FB_ADRS framebuffer address
493 VIDEO_KBD_INIT_FCT keyboard int fct
494 (i.e. i8042_kbd_init())
495 VIDEO_TSTC_FCT test char fct
497 VIDEO_GETC_FCT get char fct
499 CONFIG_CONSOLE_CURSOR cursor drawing on/off
500 (requires blink timer
502 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
503 CONFIG_CONSOLE_TIME display time/date info in
505 (requires CONFIG_CMD_DATE)
506 CONFIG_VIDEO_LOGO display Linux logo in
508 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
509 linux_logo.h for logo.
510 Requires CONFIG_VIDEO_LOGO
511 CONFIG_CONSOLE_EXTRA_INFO
512 additional board info beside
515 When CONFIG_CFB_CONSOLE is defined, video console is
516 default i/o. Serial console can be forced with
517 environment 'console=serial'.
519 When CONFIG_SILENT_CONSOLE is defined, all console
520 messages (by U-Boot and Linux!) can be silenced with
521 the "silent" environment variable. See
522 doc/README.silent for more information.
525 CONFIG_BAUDRATE - in bps
526 Select one of the baudrates listed in
527 CONFIG_SYS_BAUDRATE_TABLE, see below.
528 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
530 - Console Rx buffer length
531 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
532 the maximum receive buffer length for the SMC.
533 This option is actual only for 82xx and 8xx possible.
534 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
535 must be defined, to setup the maximum idle timeout for
538 - Interrupt driven serial port input:
539 CONFIG_SERIAL_SOFTWARE_FIFO
542 Use an interrupt handler for receiving data on the
543 serial port. It also enables using hardware handshake
544 (RTS/CTS) and UART's built-in FIFO. Set the number of
545 bytes the interrupt driven input buffer should have.
547 Leave undefined to disable this feature, including
548 disable the buffer and hardware handshake.
550 - Console UART Number:
554 If defined internal UART1 (and not UART0) is used
555 as default U-Boot console.
557 - Boot Delay: CONFIG_BOOTDELAY - in seconds
558 Delay before automatically booting the default image;
559 set to -1 to disable autoboot.
561 See doc/README.autoboot for these options that
562 work with CONFIG_BOOTDELAY. None are required.
563 CONFIG_BOOT_RETRY_TIME
564 CONFIG_BOOT_RETRY_MIN
565 CONFIG_AUTOBOOT_KEYED
566 CONFIG_AUTOBOOT_PROMPT
567 CONFIG_AUTOBOOT_DELAY_STR
568 CONFIG_AUTOBOOT_STOP_STR
569 CONFIG_AUTOBOOT_DELAY_STR2
570 CONFIG_AUTOBOOT_STOP_STR2
571 CONFIG_ZERO_BOOTDELAY_CHECK
572 CONFIG_RESET_TO_RETRY
576 Only needed when CONFIG_BOOTDELAY is enabled;
577 define a command string that is automatically executed
578 when no character is read on the console interface
579 within "Boot Delay" after reset.
582 This can be used to pass arguments to the bootm
583 command. The value of CONFIG_BOOTARGS goes into the
584 environment value "bootargs".
586 CONFIG_RAMBOOT and CONFIG_NFSBOOT
587 The value of these goes into the environment as
588 "ramboot" and "nfsboot" respectively, and can be used
589 as a convenience, when switching between booting from
595 When this option is #defined, the existence of the
596 environment variable "preboot" will be checked
597 immediately before starting the CONFIG_BOOTDELAY
598 countdown and/or running the auto-boot command resp.
599 entering interactive mode.
601 This feature is especially useful when "preboot" is
602 automatically generated or modified. For an example
603 see the LWMON board specific code: here "preboot" is
604 modified when the user holds down a certain
605 combination of keys on the (special) keyboard when
608 - Serial Download Echo Mode:
610 If defined to 1, all characters received during a
611 serial download (using the "loads" command) are
612 echoed back. This might be needed by some terminal
613 emulations (like "cu"), but may as well just take
614 time on others. This setting #define's the initial
615 value of the "loads_echo" environment variable.
617 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
619 Select one of the baudrates listed in
620 CONFIG_SYS_BAUDRATE_TABLE, see below.
623 Monitor commands can be included or excluded
624 from the build by using the #include files
625 "config_cmd_all.h" and #undef'ing unwanted
626 commands, or using "config_cmd_default.h"
627 and augmenting with additional #define's
630 The default command configuration includes all commands
631 except those marked below with a "*".
633 CONFIG_CMD_ASKENV * ask for env variable
634 CONFIG_CMD_BDI bdinfo
635 CONFIG_CMD_BEDBUG * Include BedBug Debugger
636 CONFIG_CMD_BMP * BMP support
637 CONFIG_CMD_BSP * Board specific commands
638 CONFIG_CMD_BOOTD bootd
639 CONFIG_CMD_CACHE * icache, dcache
640 CONFIG_CMD_CONSOLE coninfo
641 CONFIG_CMD_DATE * support for RTC, date/time...
642 CONFIG_CMD_DHCP * DHCP support
643 CONFIG_CMD_DIAG * Diagnostics
644 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
645 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
646 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
647 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
648 CONFIG_CMD_DTT * Digital Therm and Thermostat
649 CONFIG_CMD_ECHO echo arguments
650 CONFIG_CMD_EDITENV edit env variable
651 CONFIG_CMD_EEPROM * EEPROM read/write support
652 CONFIG_CMD_ELF * bootelf, bootvx
653 CONFIG_CMD_SAVEENV saveenv
654 CONFIG_CMD_FDC * Floppy Disk Support
655 CONFIG_CMD_FAT * FAT partition support
656 CONFIG_CMD_FDOS * Dos diskette Support
657 CONFIG_CMD_FLASH flinfo, erase, protect
658 CONFIG_CMD_FPGA FPGA device initialization support
659 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
660 CONFIG_CMD_I2C * I2C serial bus support
661 CONFIG_CMD_IDE * IDE harddisk support
662 CONFIG_CMD_IMI iminfo
663 CONFIG_CMD_IMLS List all found images
664 CONFIG_CMD_IMMAP * IMMR dump support
665 CONFIG_CMD_IRQ * irqinfo
666 CONFIG_CMD_ITEST Integer/string test of 2 values
667 CONFIG_CMD_JFFS2 * JFFS2 Support
668 CONFIG_CMD_KGDB * kgdb
669 CONFIG_CMD_LOADB loadb
670 CONFIG_CMD_LOADS loads
671 CONFIG_CMD_MD5SUM print md5 message digest
672 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
673 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
675 CONFIG_CMD_MISC Misc functions like sleep etc
676 CONFIG_CMD_MMC * MMC memory mapped support
677 CONFIG_CMD_MII * MII utility commands
678 CONFIG_CMD_MTDPARTS * MTD partition support
679 CONFIG_CMD_NAND * NAND support
680 CONFIG_CMD_NET bootp, tftpboot, rarpboot
681 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
682 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
683 CONFIG_CMD_PCI * pciinfo
684 CONFIG_CMD_PCMCIA * PCMCIA support
685 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
687 CONFIG_CMD_PORTIO * Port I/O
688 CONFIG_CMD_REGINFO * Register dump
689 CONFIG_CMD_RUN run command in env variable
690 CONFIG_CMD_SAVES * save S record dump
691 CONFIG_CMD_SCSI * SCSI Support
692 CONFIG_CMD_SDRAM * print SDRAM configuration information
693 (requires CONFIG_CMD_I2C)
694 CONFIG_CMD_SETGETDCR Support for DCR Register access
696 CONFIG_CMD_SHA1 print sha1 memory digest
697 (requires CONFIG_CMD_MEMORY)
698 CONFIG_CMD_SOURCE "source" command Support
699 CONFIG_CMD_SPI * SPI serial bus support
700 CONFIG_CMD_USB * USB support
701 CONFIG_CMD_VFD * VFD support (TRAB)
702 CONFIG_CMD_CDP * Cisco Discover Protocol support
703 CONFIG_CMD_FSL * Microblaze FSL support
706 EXAMPLE: If you want all functions except of network
707 support you can write:
709 #include "config_cmd_all.h"
710 #undef CONFIG_CMD_NET
713 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
715 Note: Don't enable the "icache" and "dcache" commands
716 (configuration option CONFIG_CMD_CACHE) unless you know
717 what you (and your U-Boot users) are doing. Data
718 cache cannot be enabled on systems like the 8xx or
719 8260 (where accesses to the IMMR region must be
720 uncached), and it cannot be disabled on all other
721 systems where we (mis-) use the data cache to hold an
722 initial stack and some data.
725 XXX - this list needs to get updated!
729 If this variable is defined, it enables watchdog
730 support. There must be support in the platform specific
731 code for a watchdog. For the 8xx and 8260 CPUs, the
732 SIU Watchdog feature is enabled in the SYPCR
736 CONFIG_VERSION_VARIABLE
737 If this variable is defined, an environment variable
738 named "ver" is created by U-Boot showing the U-Boot
739 version as printed by the "version" command.
740 This variable is readonly.
744 When CONFIG_CMD_DATE is selected, the type of the RTC
745 has to be selected, too. Define exactly one of the
748 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
749 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
750 CONFIG_RTC_MC13783 - use MC13783 RTC
751 CONFIG_RTC_MC146818 - use MC146818 RTC
752 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
753 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
754 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
755 CONFIG_RTC_DS164x - use Dallas DS164x RTC
756 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
757 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
758 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
760 Note that if the RTC uses I2C, then the I2C interface
761 must also be configured. See I2C Support, below.
764 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
765 CONFIG_PCA953X_INFO - enable pca953x info command
767 Note that if the GPIO device 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 CONFIG_CMD_DATE .
778 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
779 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
781 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
782 CONFIG_CMD_SCSI) you must configure support for at
783 least 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 CONFIG_SYS_64BIT_LBA.
804 Whithout these , LBA48 support uses 32bit variables and will 'only'
805 support disks up to 2.1TB.
807 CONFIG_SYS_64BIT_LBA:
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 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
817 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
818 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
819 maximum numbers of LUNs, SCSI ID's and target
821 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
823 - NETWORK Support (PCI):
825 Support for Intel 8254x gigabit chips.
827 CONFIG_E1000_FALLBACK_MAC
828 default MAC for empty EEPROM after production.
831 Support for Intel 82557/82559/82559ER chips.
832 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
833 write routine for first time initialisation.
836 Support for Digital 2114x chips.
837 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
838 modem chip initialisation (KS8761/QS6611).
841 Support for National dp83815 chips.
844 Support for National dp8382[01] gigabit chips.
846 - NETWORK Support (other):
848 CONFIG_DRIVER_AT91EMAC
849 Support for AT91RM9200 EMAC.
852 Define this to use reduced MII inteface
854 CONFIG_DRIVER_AT91EMAC_QUIET
855 If this defined, the driver is quiet.
856 The driver doen't show link status messages.
858 CONFIG_DRIVER_LAN91C96
859 Support for SMSC's LAN91C96 chips.
862 Define this to hold the physical address
863 of the LAN91C96's I/O space
865 CONFIG_LAN91C96_USE_32_BIT
866 Define this to enable 32 bit addressing
868 CONFIG_DRIVER_SMC91111
869 Support for SMSC's LAN91C111 chip
872 Define this to hold the physical address
873 of the device (I/O space)
875 CONFIG_SMC_USE_32_BIT
876 Define this if data bus is 32 bits
878 CONFIG_SMC_USE_IOFUNCS
879 Define this to use i/o functions instead of macros
880 (some hardware wont work with macros)
883 Support for SMSC's LAN911x and LAN921x chips
886 Define this to hold the physical address
887 of the device (I/O space)
889 CONFIG_SMC911X_32_BIT
890 Define this if data bus is 32 bits
892 CONFIG_SMC911X_16_BIT
893 Define this if data bus is 16 bits. If your processor
894 automatically converts one 32 bit word to two 16 bit
895 words you may also try CONFIG_SMC911X_32_BIT.
898 At the moment only the UHCI host controller is
899 supported (PIP405, MIP405, MPC5200); define
900 CONFIG_USB_UHCI to enable it.
901 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
902 and define CONFIG_USB_STORAGE to enable the USB
905 Supported are USB Keyboards and USB Floppy drives
907 MPC5200 USB requires additional defines:
909 for 528 MHz Clock: 0x0001bbbb
913 for differential drivers: 0x00001000
914 for single ended drivers: 0x00005000
915 for differential drivers on PSC3: 0x00000100
916 for single ended drivers on PSC3: 0x00004100
917 CONFIG_SYS_USB_EVENT_POLL
918 May be defined to allow interrupt polling
919 instead of using asynchronous interrupts
922 Define the below if you wish to use the USB console.
923 Once firmware is rebuilt from a serial console issue the
924 command "setenv stdin usbtty; setenv stdout usbtty" and
925 attach your USB cable. The Unix command "dmesg" should print
926 it has found a new device. The environment variable usbtty
927 can be set to gserial or cdc_acm to enable your device to
928 appear to a USB host as a Linux gserial device or a
929 Common Device Class Abstract Control Model serial device.
930 If you select usbtty = gserial you should be able to enumerate
932 # modprobe usbserial vendor=0xVendorID product=0xProductID
933 else if using cdc_acm, simply setting the environment
934 variable usbtty to be cdc_acm should suffice. The following
935 might be defined in YourBoardName.h
938 Define this to build a UDC device
941 Define this to have a tty type of device available to
942 talk to the UDC device
944 CONFIG_SYS_CONSOLE_IS_IN_ENV
945 Define this if you want stdin, stdout &/or stderr to
949 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
950 Derive USB clock from external clock "blah"
951 - CONFIG_SYS_USB_EXTC_CLK 0x02
953 CONFIG_SYS_USB_BRG_CLK 0xBLAH
954 Derive USB clock from brgclk
955 - CONFIG_SYS_USB_BRG_CLK 0x04
957 If you have a USB-IF assigned VendorID then you may wish to
958 define your own vendor specific values either in BoardName.h
959 or directly in usbd_vendor_info.h. If you don't define
960 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
961 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
962 should pretend to be a Linux device to it's target host.
964 CONFIG_USBD_MANUFACTURER
965 Define this string as the name of your company for
966 - CONFIG_USBD_MANUFACTURER "my company"
968 CONFIG_USBD_PRODUCT_NAME
969 Define this string as the name of your product
970 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
973 Define this as your assigned Vendor ID from the USB
974 Implementors Forum. This *must* be a genuine Vendor ID
975 to avoid polluting the USB namespace.
976 - CONFIG_USBD_VENDORID 0xFFFF
978 CONFIG_USBD_PRODUCTID
979 Define this as the unique Product ID
981 - CONFIG_USBD_PRODUCTID 0xFFFF
985 The MMC controller on the Intel PXA is supported. To
986 enable this define CONFIG_MMC. The MMC can be
987 accessed from the boot prompt by mapping the device
988 to physical memory similar to flash. Command line is
989 enabled with CONFIG_CMD_MMC. The MMC driver also works with
990 the FAT fs. This is enabled with CONFIG_CMD_FAT.
992 - Journaling Flash filesystem support:
993 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
994 CONFIG_JFFS2_NAND_DEV
995 Define these for a default partition on a NAND device
997 CONFIG_SYS_JFFS2_FIRST_SECTOR,
998 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
999 Define these for a default partition on a NOR device
1001 CONFIG_SYS_JFFS_CUSTOM_PART
1002 Define this to create an own partition. You have to provide a
1003 function struct part_info* jffs2_part_info(int part_num)
1005 If you define only one JFFS2 partition you may also want to
1006 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1007 to disable the command chpart. This is the default when you
1008 have not defined a custom partition
1013 Define this to enable standard (PC-Style) keyboard
1017 Standard PC keyboard driver with US (is default) and
1018 GERMAN key layout (switch via environment 'keymap=de') support.
1019 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1020 for cfb_console. Supports cursor blinking.
1025 Define this to enable video support (for output to
1028 CONFIG_VIDEO_CT69000
1030 Enable Chips & Technologies 69000 Video chip
1032 CONFIG_VIDEO_SMI_LYNXEM
1033 Enable Silicon Motion SMI 712/710/810 Video chip. The
1034 video output is selected via environment 'videoout'
1035 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1038 For the CT69000 and SMI_LYNXEM drivers, videomode is
1039 selected via environment 'videomode'. Two different ways
1041 - "videomode=num" 'num' is a standard LiLo mode numbers.
1042 Following standard modes are supported (* is default):
1044 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1045 -------------+---------------------------------------------
1046 8 bits | 0x301* 0x303 0x305 0x161 0x307
1047 15 bits | 0x310 0x313 0x316 0x162 0x319
1048 16 bits | 0x311 0x314 0x317 0x163 0x31A
1049 24 bits | 0x312 0x315 0x318 ? 0x31B
1050 -------------+---------------------------------------------
1051 (i.e. setenv videomode 317; saveenv; reset;)
1053 - "videomode=bootargs" all the video parameters are parsed
1054 from the bootargs. (See drivers/video/videomodes.c)
1057 CONFIG_VIDEO_SED13806
1058 Enable Epson SED13806 driver. This driver supports 8bpp
1059 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1060 or CONFIG_VIDEO_SED13806_16BPP
1065 Define this to enable a custom keyboard support.
1066 This simply calls drv_keyboard_init() which must be
1067 defined in your board-specific files.
1068 The only board using this so far is RBC823.
1070 - LCD Support: CONFIG_LCD
1072 Define this to enable LCD support (for output to LCD
1073 display); also select one of the supported displays
1074 by defining one of these:
1078 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1080 CONFIG_NEC_NL6448AC33:
1082 NEC NL6448AC33-18. Active, color, single scan.
1084 CONFIG_NEC_NL6448BC20
1086 NEC NL6448BC20-08. 6.5", 640x480.
1087 Active, color, single scan.
1089 CONFIG_NEC_NL6448BC33_54
1091 NEC NL6448BC33-54. 10.4", 640x480.
1092 Active, color, single scan.
1096 Sharp 320x240. Active, color, single scan.
1097 It isn't 16x9, and I am not sure what it is.
1099 CONFIG_SHARP_LQ64D341
1101 Sharp LQ64D341 display, 640x480.
1102 Active, color, single scan.
1106 HLD1045 display, 640x480.
1107 Active, color, single scan.
1111 Optrex CBL50840-2 NF-FW 99 22 M5
1113 Hitachi LMG6912RPFC-00T
1117 320x240. Black & white.
1119 Normally display is black on white background; define
1120 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1122 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1124 If this option is set, the environment is checked for
1125 a variable "splashimage". If found, the usual display
1126 of logo, copyright and system information on the LCD
1127 is suppressed and the BMP image at the address
1128 specified in "splashimage" is loaded instead. The
1129 console is redirected to the "nulldev", too. This
1130 allows for a "silent" boot where a splash screen is
1131 loaded very quickly after power-on.
1133 CONFIG_SPLASH_SCREEN_ALIGN
1135 If this option is set the splash image can be freely positioned
1136 on the screen. Environment variable "splashpos" specifies the
1137 position as "x,y". If a positive number is given it is used as
1138 number of pixel from left/top. If a negative number is given it
1139 is used as number of pixel from right/bottom. You can also
1140 specify 'm' for centering the image.
1143 setenv splashpos m,m
1144 => image at center of screen
1146 setenv splashpos 30,20
1147 => image at x = 30 and y = 20
1149 setenv splashpos -10,m
1150 => vertically centered image
1151 at x = dspWidth - bmpWidth - 9
1153 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1155 If this option is set, additionally to standard BMP
1156 images, gzipped BMP images can be displayed via the
1157 splashscreen support or the bmp command.
1159 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1161 If this option is set, 8-bit RLE compressed BMP images
1162 can be displayed via the splashscreen support or the
1165 - Compression support:
1168 If this option is set, support for bzip2 compressed
1169 images is included. If not, only uncompressed and gzip
1170 compressed images are supported.
1172 NOTE: the bzip2 algorithm requires a lot of RAM, so
1173 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1178 If this option is set, support for lzma compressed
1181 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1182 requires an amount of dynamic memory that is given by the
1185 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1187 Where lc and lp stand for, respectively, Literal context bits
1188 and Literal pos bits.
1190 This value is upper-bounded by 14MB in the worst case. Anyway,
1191 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1192 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1193 a very small buffer.
1195 Use the lzmainfo tool to determinate the lc and lp values and
1196 then calculate the amount of needed dynamic memory (ensuring
1197 the appropriate CONFIG_SYS_MALLOC_LEN value).
1202 The address of PHY on MII bus.
1204 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1206 The clock frequency of the MII bus
1210 If this option is set, support for speed/duplex
1211 detection of gigabit PHY is included.
1213 CONFIG_PHY_RESET_DELAY
1215 Some PHY like Intel LXT971A need extra delay after
1216 reset before any MII register access is possible.
1217 For such PHY, set this option to the usec delay
1218 required. (minimum 300usec for LXT971A)
1220 CONFIG_PHY_CMD_DELAY (ppc4xx)
1222 Some PHY like Intel LXT971A need extra delay after
1223 command issued before MII status register can be read
1233 Define a default value for Ethernet address to use
1234 for the respective Ethernet interface, in case this
1235 is not determined automatically.
1240 Define a default value for the IP address to use for
1241 the default Ethernet interface, in case this is not
1242 determined through e.g. bootp.
1244 - Server IP address:
1247 Defines a default value for the IP address of a TFTP
1248 server to contact when using the "tftboot" command.
1250 CONFIG_KEEP_SERVERADDR
1252 Keeps the server's MAC address, in the env 'serveraddr'
1253 for passing to bootargs (like Linux's netconsole option)
1255 - Multicast TFTP Mode:
1258 Defines whether you want to support multicast TFTP as per
1259 rfc-2090; for example to work with atftp. Lets lots of targets
1260 tftp down the same boot image concurrently. Note: the Ethernet
1261 driver in use must provide a function: mcast() to join/leave a
1264 CONFIG_BOOTP_RANDOM_DELAY
1265 - BOOTP Recovery Mode:
1266 CONFIG_BOOTP_RANDOM_DELAY
1268 If you have many targets in a network that try to
1269 boot using BOOTP, you may want to avoid that all
1270 systems send out BOOTP requests at precisely the same
1271 moment (which would happen for instance at recovery
1272 from a power failure, when all systems will try to
1273 boot, thus flooding the BOOTP server. Defining
1274 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1275 inserted before sending out BOOTP requests. The
1276 following delays are inserted then:
1278 1st BOOTP request: delay 0 ... 1 sec
1279 2nd BOOTP request: delay 0 ... 2 sec
1280 3rd BOOTP request: delay 0 ... 4 sec
1282 BOOTP requests: delay 0 ... 8 sec
1284 - DHCP Advanced Options:
1285 You can fine tune the DHCP functionality by defining
1286 CONFIG_BOOTP_* symbols:
1288 CONFIG_BOOTP_SUBNETMASK
1289 CONFIG_BOOTP_GATEWAY
1290 CONFIG_BOOTP_HOSTNAME
1291 CONFIG_BOOTP_NISDOMAIN
1292 CONFIG_BOOTP_BOOTPATH
1293 CONFIG_BOOTP_BOOTFILESIZE
1296 CONFIG_BOOTP_SEND_HOSTNAME
1297 CONFIG_BOOTP_NTPSERVER
1298 CONFIG_BOOTP_TIMEOFFSET
1299 CONFIG_BOOTP_VENDOREX
1301 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1302 environment variable, not the BOOTP server.
1304 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1305 serverip from a DHCP server, it is possible that more
1306 than one DNS serverip is offered to the client.
1307 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1308 serverip will be stored in the additional environment
1309 variable "dnsip2". The first DNS serverip is always
1310 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1313 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1314 to do a dynamic update of a DNS server. To do this, they
1315 need the hostname of the DHCP requester.
1316 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1317 of the "hostname" environment variable is passed as
1318 option 12 to the DHCP server.
1320 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1322 A 32bit value in microseconds for a delay between
1323 receiving a "DHCP Offer" and sending the "DHCP Request".
1324 This fixes a problem with certain DHCP servers that don't
1325 respond 100% of the time to a "DHCP request". E.g. On an
1326 AT91RM9200 processor running at 180MHz, this delay needed
1327 to be *at least* 15,000 usec before a Windows Server 2003
1328 DHCP server would reply 100% of the time. I recommend at
1329 least 50,000 usec to be safe. The alternative is to hope
1330 that one of the retries will be successful but note that
1331 the DHCP timeout and retry process takes a longer than
1335 CONFIG_CDP_DEVICE_ID
1337 The device id used in CDP trigger frames.
1339 CONFIG_CDP_DEVICE_ID_PREFIX
1341 A two character string which is prefixed to the MAC address
1346 A printf format string which contains the ascii name of
1347 the port. Normally is set to "eth%d" which sets
1348 eth0 for the first Ethernet, eth1 for the second etc.
1350 CONFIG_CDP_CAPABILITIES
1352 A 32bit integer which indicates the device capabilities;
1353 0x00000010 for a normal host which does not forwards.
1357 An ascii string containing the version of the software.
1361 An ascii string containing the name of the platform.
1365 A 32bit integer sent on the trigger.
1367 CONFIG_CDP_POWER_CONSUMPTION
1369 A 16bit integer containing the power consumption of the
1370 device in .1 of milliwatts.
1372 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1374 A byte containing the id of the VLAN.
1376 - Status LED: CONFIG_STATUS_LED
1378 Several configurations allow to display the current
1379 status using a LED. For instance, the LED will blink
1380 fast while running U-Boot code, stop blinking as
1381 soon as a reply to a BOOTP request was received, and
1382 start blinking slow once the Linux kernel is running
1383 (supported by a status LED driver in the Linux
1384 kernel). Defining CONFIG_STATUS_LED enables this
1387 - CAN Support: CONFIG_CAN_DRIVER
1389 Defining CONFIG_CAN_DRIVER enables CAN driver support
1390 on those systems that support this (optional)
1391 feature, like the TQM8xxL modules.
1393 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1395 These enable I2C serial bus commands. Defining either of
1396 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1397 include the appropriate I2C driver for the selected CPU.
1399 This will allow you to use i2c commands at the u-boot
1400 command line (as long as you set CONFIG_CMD_I2C in
1401 CONFIG_COMMANDS) and communicate with i2c based realtime
1402 clock chips. See common/cmd_i2c.c for a description of the
1403 command line interface.
1405 CONFIG_HARD_I2C selects a hardware I2C controller.
1407 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1408 bit-banging) driver instead of CPM or similar hardware
1411 There are several other quantities that must also be
1412 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1414 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1415 to be the frequency (in Hz) at which you wish your i2c bus
1416 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1417 the CPU's i2c node address).
1419 Now, the u-boot i2c code for the mpc8xx
1420 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1421 and so its address should therefore be cleared to 0 (See,
1422 eg, MPC823e User's Manual p.16-473). So, set
1423 CONFIG_SYS_I2C_SLAVE to 0.
1425 CONFIG_SYS_I2C_INIT_MPC5XXX
1427 When a board is reset during an i2c bus transfer
1428 chips might think that the current transfer is still
1429 in progress. Reset the slave devices by sending start
1430 commands until the slave device responds.
1432 That's all that's required for CONFIG_HARD_I2C.
1434 If you use the software i2c interface (CONFIG_SOFT_I2C)
1435 then the following macros need to be defined (examples are
1436 from include/configs/lwmon.h):
1440 (Optional). Any commands necessary to enable the I2C
1441 controller or configure ports.
1443 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1447 (Only for MPC8260 CPU). The I/O port to use (the code
1448 assumes both bits are on the same port). Valid values
1449 are 0..3 for ports A..D.
1453 The code necessary to make the I2C data line active
1454 (driven). If the data line is open collector, this
1457 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1461 The code necessary to make the I2C data line tri-stated
1462 (inactive). If the data line is open collector, this
1465 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1469 Code that returns TRUE if the I2C data line is high,
1472 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1476 If <bit> is TRUE, sets the I2C data line high. If it
1477 is FALSE, it clears it (low).
1479 eg: #define I2C_SDA(bit) \
1480 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1481 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1485 If <bit> is TRUE, sets the I2C clock line high. If it
1486 is FALSE, it clears it (low).
1488 eg: #define I2C_SCL(bit) \
1489 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1490 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1494 This delay is invoked four times per clock cycle so this
1495 controls the rate of data transfer. The data rate thus
1496 is 1 / (I2C_DELAY * 4). Often defined to be something
1499 #define I2C_DELAY udelay(2)
1501 CONFIG_SYS_I2C_INIT_BOARD
1503 When a board is reset during an i2c bus transfer
1504 chips might think that the current transfer is still
1505 in progress. On some boards it is possible to access
1506 the i2c SCLK line directly, either by using the
1507 processor pin as a GPIO or by having a second pin
1508 connected to the bus. If this option is defined a
1509 custom i2c_init_board() routine in boards/xxx/board.c
1510 is run early in the boot sequence.
1512 CONFIG_SYS_I2C_BOARD_LATE_INIT
1514 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1515 defined a custom i2c_board_late_init() routine in
1516 boards/xxx/board.c is run AFTER the operations in i2c_init()
1517 is completed. This callpoint can be used to unreset i2c bus
1518 using CPU i2c controller register accesses for CPUs whose i2c
1519 controller provide such a method. It is called at the end of
1520 i2c_init() to allow i2c_init operations to setup the i2c bus
1521 controller on the CPU (e.g. setting bus speed & slave address).
1523 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1525 This option enables configuration of bi_iic_fast[] flags
1526 in u-boot bd_info structure based on u-boot environment
1527 variable "i2cfast". (see also i2cfast)
1529 CONFIG_I2C_MULTI_BUS
1531 This option allows the use of multiple I2C buses, each of which
1532 must have a controller. At any point in time, only one bus is
1533 active. To switch to a different bus, use the 'i2c dev' command.
1534 Note that bus numbering is zero-based.
1536 CONFIG_SYS_I2C_NOPROBES
1538 This option specifies a list of I2C devices that will be skipped
1539 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1540 is set, specify a list of bus-device pairs. Otherwise, specify
1541 a 1D array of device addresses
1544 #undef CONFIG_I2C_MULTI_BUS
1545 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1547 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1549 #define CONFIG_I2C_MULTI_BUS
1550 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1552 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1554 CONFIG_SYS_SPD_BUS_NUM
1556 If defined, then this indicates the I2C bus number for DDR SPD.
1557 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1559 CONFIG_SYS_RTC_BUS_NUM
1561 If defined, then this indicates the I2C bus number for the RTC.
1562 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1564 CONFIG_SYS_DTT_BUS_NUM
1566 If defined, then this indicates the I2C bus number for the DTT.
1567 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1569 CONFIG_SYS_I2C_DTT_ADDR:
1571 If defined, specifies the I2C address of the DTT device.
1572 If not defined, then U-Boot uses predefined value for
1573 specified DTT device.
1577 Define this option if you want to use Freescale's I2C driver in
1578 drivers/i2c/fsl_i2c.c.
1582 Define this option if you have I2C devices reached over 1 .. n
1583 I2C Muxes like the pca9544a. This option addes a new I2C
1584 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1585 new I2C Bus to the existing I2C Busses. If you select the
1586 new Bus with "i2c dev", u-bbot sends first the commandos for
1587 the muxes to activate this new "bus".
1589 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1593 Adding a new I2C Bus reached over 2 pca9544a muxes
1594 The First mux with address 70 and channel 6
1595 The Second mux with address 71 and channel 4
1597 => i2c bus pca9544a:70:6:pca9544a:71:4
1599 Use the "i2c bus" command without parameter, to get a list
1600 of I2C Busses with muxes:
1603 Busses reached over muxes:
1605 reached over Mux(es):
1608 reached over Mux(es):
1613 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1614 u-boot sends First the Commando to the mux@70 to enable
1615 channel 6, and then the Commando to the mux@71 to enable
1618 After that, you can use the "normal" i2c commands as
1619 usual, to communicate with your I2C devices behind
1622 This option is actually implemented for the bitbanging
1623 algorithm in common/soft_i2c.c and for the Hardware I2C
1624 Bus on the MPC8260. But it should be not so difficult
1625 to add this option to other architectures.
1627 CONFIG_SOFT_I2C_READ_REPEATED_START
1629 defining this will force the i2c_read() function in
1630 the soft_i2c driver to perform an I2C repeated start
1631 between writing the address pointer and reading the
1632 data. If this define is omitted the default behaviour
1633 of doing a stop-start sequence will be used. Most I2C
1634 devices can use either method, but some require one or
1637 - SPI Support: CONFIG_SPI
1639 Enables SPI driver (so far only tested with
1640 SPI EEPROM, also an instance works with Crystal A/D and
1641 D/As on the SACSng board)
1645 Enables extended (16-bit) SPI EEPROM addressing.
1646 (symmetrical to CONFIG_I2C_X)
1650 Enables a software (bit-bang) SPI driver rather than
1651 using hardware support. This is a general purpose
1652 driver that only requires three general I/O port pins
1653 (two outputs, one input) to function. If this is
1654 defined, the board configuration must define several
1655 SPI configuration items (port pins to use, etc). For
1656 an example, see include/configs/sacsng.h.
1660 Enables a hardware SPI driver for general-purpose reads
1661 and writes. As with CONFIG_SOFT_SPI, the board configuration
1662 must define a list of chip-select function pointers.
1663 Currently supported on some MPC8xxx processors. For an
1664 example, see include/configs/mpc8349emds.h.
1668 Enables the driver for the SPI controllers on i.MX and MXC
1669 SoCs. Currently only i.MX31 is supported.
1671 - FPGA Support: CONFIG_FPGA
1673 Enables FPGA subsystem.
1675 CONFIG_FPGA_<vendor>
1677 Enables support for specific chip vendors.
1680 CONFIG_FPGA_<family>
1682 Enables support for FPGA family.
1683 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1687 Specify the number of FPGA devices to support.
1689 CONFIG_SYS_FPGA_PROG_FEEDBACK
1691 Enable printing of hash marks during FPGA configuration.
1693 CONFIG_SYS_FPGA_CHECK_BUSY
1695 Enable checks on FPGA configuration interface busy
1696 status by the configuration function. This option
1697 will require a board or device specific function to
1702 If defined, a function that provides delays in the FPGA
1703 configuration driver.
1705 CONFIG_SYS_FPGA_CHECK_CTRLC
1706 Allow Control-C to interrupt FPGA configuration
1708 CONFIG_SYS_FPGA_CHECK_ERROR
1710 Check for configuration errors during FPGA bitfile
1711 loading. For example, abort during Virtex II
1712 configuration if the INIT_B line goes low (which
1713 indicated a CRC error).
1715 CONFIG_SYS_FPGA_WAIT_INIT
1717 Maximum time to wait for the INIT_B line to deassert
1718 after PROB_B has been deasserted during a Virtex II
1719 FPGA configuration sequence. The default time is 500
1722 CONFIG_SYS_FPGA_WAIT_BUSY
1724 Maximum time to wait for BUSY to deassert during
1725 Virtex II FPGA configuration. The default is 5 ms.
1727 CONFIG_SYS_FPGA_WAIT_CONFIG
1729 Time to wait after FPGA configuration. The default is
1732 - Configuration Management:
1735 If defined, this string will be added to the U-Boot
1736 version information (U_BOOT_VERSION)
1738 - Vendor Parameter Protection:
1740 U-Boot considers the values of the environment
1741 variables "serial#" (Board Serial Number) and
1742 "ethaddr" (Ethernet Address) to be parameters that
1743 are set once by the board vendor / manufacturer, and
1744 protects these variables from casual modification by
1745 the user. Once set, these variables are read-only,
1746 and write or delete attempts are rejected. You can
1747 change this behaviour:
1749 If CONFIG_ENV_OVERWRITE is #defined in your config
1750 file, the write protection for vendor parameters is
1751 completely disabled. Anybody can change or delete
1754 Alternatively, if you #define _both_ CONFIG_ETHADDR
1755 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1756 Ethernet address is installed in the environment,
1757 which can be changed exactly ONCE by the user. [The
1758 serial# is unaffected by this, i. e. it remains
1764 Define this variable to enable the reservation of
1765 "protected RAM", i. e. RAM which is not overwritten
1766 by U-Boot. Define CONFIG_PRAM to hold the number of
1767 kB you want to reserve for pRAM. You can overwrite
1768 this default value by defining an environment
1769 variable "pram" to the number of kB you want to
1770 reserve. Note that the board info structure will
1771 still show the full amount of RAM. If pRAM is
1772 reserved, a new environment variable "mem" will
1773 automatically be defined to hold the amount of
1774 remaining RAM in a form that can be passed as boot
1775 argument to Linux, for instance like that:
1777 setenv bootargs ... mem=\${mem}
1780 This way you can tell Linux not to use this memory,
1781 either, which results in a memory region that will
1782 not be affected by reboots.
1784 *WARNING* If your board configuration uses automatic
1785 detection of the RAM size, you must make sure that
1786 this memory test is non-destructive. So far, the
1787 following board configurations are known to be
1790 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1791 HERMES, IP860, RPXlite, LWMON, LANTEC,
1792 PCU_E, FLAGADM, TQM8260
1797 Define this variable to stop the system in case of a
1798 fatal error, so that you have to reset it manually.
1799 This is probably NOT a good idea for an embedded
1800 system where you want the system to reboot
1801 automatically as fast as possible, but it may be
1802 useful during development since you can try to debug
1803 the conditions that lead to the situation.
1805 CONFIG_NET_RETRY_COUNT
1807 This variable defines the number of retries for
1808 network operations like ARP, RARP, TFTP, or BOOTP
1809 before giving up the operation. If not defined, a
1810 default value of 5 is used.
1814 Timeout waiting for an ARP reply in milliseconds.
1816 - Command Interpreter:
1817 CONFIG_AUTO_COMPLETE
1819 Enable auto completion of commands using TAB.
1821 Note that this feature has NOT been implemented yet
1822 for the "hush" shell.
1825 CONFIG_SYS_HUSH_PARSER
1827 Define this variable to enable the "hush" shell (from
1828 Busybox) as command line interpreter, thus enabling
1829 powerful command line syntax like
1830 if...then...else...fi conditionals or `&&' and '||'
1831 constructs ("shell scripts").
1833 If undefined, you get the old, much simpler behaviour
1834 with a somewhat smaller memory footprint.
1837 CONFIG_SYS_PROMPT_HUSH_PS2
1839 This defines the secondary prompt string, which is
1840 printed when the command interpreter needs more input
1841 to complete a command. Usually "> ".
1845 In the current implementation, the local variables
1846 space and global environment variables space are
1847 separated. Local variables are those you define by
1848 simply typing `name=value'. To access a local
1849 variable later on, you have write `$name' or
1850 `${name}'; to execute the contents of a variable
1851 directly type `$name' at the command prompt.
1853 Global environment variables are those you use
1854 setenv/printenv to work with. To run a command stored
1855 in such a variable, you need to use the run command,
1856 and you must not use the '$' sign to access them.
1858 To store commands and special characters in a
1859 variable, please use double quotation marks
1860 surrounding the whole text of the variable, instead
1861 of the backslashes before semicolons and special
1864 - Commandline Editing and History:
1865 CONFIG_CMDLINE_EDITING
1867 Enable editing and History functions for interactive
1868 commandline input operations
1870 - Default Environment:
1871 CONFIG_EXTRA_ENV_SETTINGS
1873 Define this to contain any number of null terminated
1874 strings (variable = value pairs) that will be part of
1875 the default environment compiled into the boot image.
1877 For example, place something like this in your
1878 board's config file:
1880 #define CONFIG_EXTRA_ENV_SETTINGS \
1884 Warning: This method is based on knowledge about the
1885 internal format how the environment is stored by the
1886 U-Boot code. This is NOT an official, exported
1887 interface! Although it is unlikely that this format
1888 will change soon, there is no guarantee either.
1889 You better know what you are doing here.
1891 Note: overly (ab)use of the default environment is
1892 discouraged. Make sure to check other ways to preset
1893 the environment like the "source" command or the
1896 - DataFlash Support:
1897 CONFIG_HAS_DATAFLASH
1899 Defining this option enables DataFlash features and
1900 allows to read/write in Dataflash via the standard
1903 - SystemACE Support:
1906 Adding this option adds support for Xilinx SystemACE
1907 chips attached via some sort of local bus. The address
1908 of the chip must also be defined in the
1909 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
1911 #define CONFIG_SYSTEMACE
1912 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
1914 When SystemACE support is added, the "ace" device type
1915 becomes available to the fat commands, i.e. fatls.
1917 - TFTP Fixed UDP Port:
1920 If this is defined, the environment variable tftpsrcp
1921 is used to supply the TFTP UDP source port value.
1922 If tftpsrcp isn't defined, the normal pseudo-random port
1923 number generator is used.
1925 Also, the environment variable tftpdstp is used to supply
1926 the TFTP UDP destination port value. If tftpdstp isn't
1927 defined, the normal port 69 is used.
1929 The purpose for tftpsrcp is to allow a TFTP server to
1930 blindly start the TFTP transfer using the pre-configured
1931 target IP address and UDP port. This has the effect of
1932 "punching through" the (Windows XP) firewall, allowing
1933 the remainder of the TFTP transfer to proceed normally.
1934 A better solution is to properly configure the firewall,
1935 but sometimes that is not allowed.
1937 - Show boot progress:
1938 CONFIG_SHOW_BOOT_PROGRESS
1940 Defining this option allows to add some board-
1941 specific code (calling a user-provided function
1942 "show_boot_progress(int)") that enables you to show
1943 the system's boot progress on some display (for
1944 example, some LED's) on your board. At the moment,
1945 the following checkpoints are implemented:
1947 Legacy uImage format:
1950 1 common/cmd_bootm.c before attempting to boot an image
1951 -1 common/cmd_bootm.c Image header has bad magic number
1952 2 common/cmd_bootm.c Image header has correct magic number
1953 -2 common/cmd_bootm.c Image header has bad checksum
1954 3 common/cmd_bootm.c Image header has correct checksum
1955 -3 common/cmd_bootm.c Image data has bad checksum
1956 4 common/cmd_bootm.c Image data has correct checksum
1957 -4 common/cmd_bootm.c Image is for unsupported architecture
1958 5 common/cmd_bootm.c Architecture check OK
1959 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1960 6 common/cmd_bootm.c Image Type check OK
1961 -6 common/cmd_bootm.c gunzip uncompression error
1962 -7 common/cmd_bootm.c Unimplemented compression type
1963 7 common/cmd_bootm.c Uncompression OK
1964 8 common/cmd_bootm.c No uncompress/copy overwrite error
1965 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1967 9 common/image.c Start initial ramdisk verification
1968 -10 common/image.c Ramdisk header has bad magic number
1969 -11 common/image.c Ramdisk header has bad checksum
1970 10 common/image.c Ramdisk header is OK
1971 -12 common/image.c Ramdisk data has bad checksum
1972 11 common/image.c Ramdisk data has correct checksum
1973 12 common/image.c Ramdisk verification complete, start loading
1974 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
1975 13 common/image.c Start multifile image verification
1976 14 common/image.c No initial ramdisk, no multifile, continue.
1978 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
1980 -30 arch/powerpc/lib/board.c Fatal error, hang the system
1981 -31 post/post.c POST test failed, detected by post_output_backlog()
1982 -32 post/post.c POST test failed, detected by post_run_single()
1984 34 common/cmd_doc.c before loading a Image from a DOC device
1985 -35 common/cmd_doc.c Bad usage of "doc" command
1986 35 common/cmd_doc.c correct usage of "doc" command
1987 -36 common/cmd_doc.c No boot device
1988 36 common/cmd_doc.c correct boot device
1989 -37 common/cmd_doc.c Unknown Chip ID on boot device
1990 37 common/cmd_doc.c correct chip ID found, device available
1991 -38 common/cmd_doc.c Read Error on boot device
1992 38 common/cmd_doc.c reading Image header from DOC device OK
1993 -39 common/cmd_doc.c Image header has bad magic number
1994 39 common/cmd_doc.c Image header has correct magic number
1995 -40 common/cmd_doc.c Error reading Image from DOC device
1996 40 common/cmd_doc.c Image header has correct magic number
1997 41 common/cmd_ide.c before loading a Image from a IDE device
1998 -42 common/cmd_ide.c Bad usage of "ide" command
1999 42 common/cmd_ide.c correct usage of "ide" command
2000 -43 common/cmd_ide.c No boot device
2001 43 common/cmd_ide.c boot device found
2002 -44 common/cmd_ide.c Device not available
2003 44 common/cmd_ide.c Device available
2004 -45 common/cmd_ide.c wrong partition selected
2005 45 common/cmd_ide.c partition selected
2006 -46 common/cmd_ide.c Unknown partition table
2007 46 common/cmd_ide.c valid partition table found
2008 -47 common/cmd_ide.c Invalid partition type
2009 47 common/cmd_ide.c correct partition type
2010 -48 common/cmd_ide.c Error reading Image Header on boot device
2011 48 common/cmd_ide.c reading Image Header from IDE device OK
2012 -49 common/cmd_ide.c Image header has bad magic number
2013 49 common/cmd_ide.c Image header has correct magic number
2014 -50 common/cmd_ide.c Image header has bad checksum
2015 50 common/cmd_ide.c Image header has correct checksum
2016 -51 common/cmd_ide.c Error reading Image from IDE device
2017 51 common/cmd_ide.c reading Image from IDE device OK
2018 52 common/cmd_nand.c before loading a Image from a NAND device
2019 -53 common/cmd_nand.c Bad usage of "nand" command
2020 53 common/cmd_nand.c correct usage of "nand" command
2021 -54 common/cmd_nand.c No boot device
2022 54 common/cmd_nand.c boot device found
2023 -55 common/cmd_nand.c Unknown Chip ID on boot device
2024 55 common/cmd_nand.c correct chip ID found, device available
2025 -56 common/cmd_nand.c Error reading Image Header on boot device
2026 56 common/cmd_nand.c reading Image Header from NAND device OK
2027 -57 common/cmd_nand.c Image header has bad magic number
2028 57 common/cmd_nand.c Image header has correct magic number
2029 -58 common/cmd_nand.c Error reading Image from NAND device
2030 58 common/cmd_nand.c reading Image from NAND device OK
2032 -60 common/env_common.c Environment has a bad CRC, using default
2034 64 net/eth.c starting with Ethernet configuration.
2035 -64 net/eth.c no Ethernet found.
2036 65 net/eth.c Ethernet found.
2038 -80 common/cmd_net.c usage wrong
2039 80 common/cmd_net.c before calling NetLoop()
2040 -81 common/cmd_net.c some error in NetLoop() occurred
2041 81 common/cmd_net.c NetLoop() back without error
2042 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2043 82 common/cmd_net.c trying automatic boot
2044 83 common/cmd_net.c running "source" command
2045 -83 common/cmd_net.c some error in automatic boot or "source" command
2046 84 common/cmd_net.c end without errors
2051 100 common/cmd_bootm.c Kernel FIT Image has correct format
2052 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2053 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2054 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2055 102 common/cmd_bootm.c Kernel unit name specified
2056 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2057 103 common/cmd_bootm.c Found configuration node
2058 104 common/cmd_bootm.c Got kernel subimage node offset
2059 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2060 105 common/cmd_bootm.c Kernel subimage hash verification OK
2061 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2062 106 common/cmd_bootm.c Architecture check OK
2063 -106 common/cmd_bootm.c Kernel subimage has wrong type
2064 107 common/cmd_bootm.c Kernel subimage type OK
2065 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2066 108 common/cmd_bootm.c Got kernel subimage data/size
2067 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2068 -109 common/cmd_bootm.c Can't get kernel subimage type
2069 -110 common/cmd_bootm.c Can't get kernel subimage comp
2070 -111 common/cmd_bootm.c Can't get kernel subimage os
2071 -112 common/cmd_bootm.c Can't get kernel subimage load address
2072 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2074 120 common/image.c Start initial ramdisk verification
2075 -120 common/image.c Ramdisk FIT image has incorrect format
2076 121 common/image.c Ramdisk FIT image has correct format
2077 122 common/image.c No ramdisk subimage unit name, using configuration
2078 -122 common/image.c Can't get configuration for ramdisk subimage
2079 123 common/image.c Ramdisk unit name specified
2080 -124 common/image.c Can't get ramdisk subimage node offset
2081 125 common/image.c Got ramdisk subimage node offset
2082 -125 common/image.c Ramdisk subimage hash verification failed
2083 126 common/image.c Ramdisk subimage hash verification OK
2084 -126 common/image.c Ramdisk subimage for unsupported architecture
2085 127 common/image.c Architecture check OK
2086 -127 common/image.c Can't get ramdisk subimage data/size
2087 128 common/image.c Got ramdisk subimage data/size
2088 129 common/image.c Can't get ramdisk load address
2089 -129 common/image.c Got ramdisk load address
2091 -130 common/cmd_doc.c Incorrect FIT image format
2092 131 common/cmd_doc.c FIT image format OK
2094 -140 common/cmd_ide.c Incorrect FIT image format
2095 141 common/cmd_ide.c FIT image format OK
2097 -150 common/cmd_nand.c Incorrect FIT image format
2098 151 common/cmd_nand.c FIT image format OK
2100 - Automatic software updates via TFTP server
2102 CONFIG_UPDATE_TFTP_CNT_MAX
2103 CONFIG_UPDATE_TFTP_MSEC_MAX
2105 These options enable and control the auto-update feature;
2106 for a more detailed description refer to doc/README.update.
2108 - MTD Support (mtdparts command, UBI support)
2111 Adds the MTD device infrastructure from the Linux kernel.
2112 Needed for mtdparts command support.
2114 CONFIG_MTD_PARTITIONS
2116 Adds the MTD partitioning infrastructure from the Linux
2117 kernel. Needed for UBI support.
2123 [so far only for SMDK2400 and TRAB boards]
2125 - Modem support enable:
2126 CONFIG_MODEM_SUPPORT
2128 - RTS/CTS Flow control enable:
2131 - Modem debug support:
2132 CONFIG_MODEM_SUPPORT_DEBUG
2134 Enables debugging stuff (char screen[1024], dbg())
2135 for modem support. Useful only with BDI2000.
2137 - Interrupt support (PPC):
2139 There are common interrupt_init() and timer_interrupt()
2140 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2141 for CPU specific initialization. interrupt_init_cpu()
2142 should set decrementer_count to appropriate value. If
2143 CPU resets decrementer automatically after interrupt
2144 (ppc4xx) it should set decrementer_count to zero.
2145 timer_interrupt() calls timer_interrupt_cpu() for CPU
2146 specific handling. If board has watchdog / status_led
2147 / other_activity_monitor it works automatically from
2148 general timer_interrupt().
2152 In the target system modem support is enabled when a
2153 specific key (key combination) is pressed during
2154 power-on. Otherwise U-Boot will boot normally
2155 (autoboot). The key_pressed() function is called from
2156 board_init(). Currently key_pressed() is a dummy
2157 function, returning 1 and thus enabling modem
2160 If there are no modem init strings in the
2161 environment, U-Boot proceed to autoboot; the
2162 previous output (banner, info printfs) will be
2165 See also: doc/README.Modem
2168 Configuration Settings:
2169 -----------------------
2171 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2172 undefine this when you're short of memory.
2174 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2175 width of the commands listed in the 'help' command output.
2177 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2178 prompt for user input.
2180 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2182 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2184 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2186 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2187 the application (usually a Linux kernel) when it is
2190 - CONFIG_SYS_BAUDRATE_TABLE:
2191 List of legal baudrate settings for this board.
2193 - CONFIG_SYS_CONSOLE_INFO_QUIET
2194 Suppress display of console information at boot.
2196 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2197 If the board specific function
2198 extern int overwrite_console (void);
2199 returns 1, the stdin, stderr and stdout are switched to the
2200 serial port, else the settings in the environment are used.
2202 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2203 Enable the call to overwrite_console().
2205 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2206 Enable overwrite of previous console environment settings.
2208 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2209 Begin and End addresses of the area used by the
2212 - CONFIG_SYS_ALT_MEMTEST:
2213 Enable an alternate, more extensive memory test.
2215 - CONFIG_SYS_MEMTEST_SCRATCH:
2216 Scratch address used by the alternate memory test
2217 You only need to set this if address zero isn't writeable
2219 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2220 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2221 this specified memory area will get subtracted from the top
2222 (end) of RAM and won't get "touched" at all by U-Boot. By
2223 fixing up gd->ram_size the Linux kernel should gets passed
2224 the now "corrected" memory size and won't touch it either.
2225 This should work for arch/ppc and arch/powerpc. Only Linux
2226 board ports in arch/powerpc with bootwrapper support that
2227 recalculate the memory size from the SDRAM controller setup
2228 will have to get fixed in Linux additionally.
2230 This option can be used as a workaround for the 440EPx/GRx
2231 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2234 WARNING: Please make sure that this value is a multiple of
2235 the Linux page size (normally 4k). If this is not the case,
2236 then the end address of the Linux memory will be located at a
2237 non page size aligned address and this could cause major
2240 - CONFIG_SYS_TFTP_LOADADDR:
2241 Default load address for network file downloads
2243 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2244 Enable temporary baudrate change while serial download
2246 - CONFIG_SYS_SDRAM_BASE:
2247 Physical start address of SDRAM. _Must_ be 0 here.
2249 - CONFIG_SYS_MBIO_BASE:
2250 Physical start address of Motherboard I/O (if using a
2253 - CONFIG_SYS_FLASH_BASE:
2254 Physical start address of Flash memory.
2256 - CONFIG_SYS_MONITOR_BASE:
2257 Physical start address of boot monitor code (set by
2258 make config files to be same as the text base address
2259 (TEXT_BASE) used when linking) - same as
2260 CONFIG_SYS_FLASH_BASE when booting from flash.
2262 - CONFIG_SYS_MONITOR_LEN:
2263 Size of memory reserved for monitor code, used to
2264 determine _at_compile_time_ (!) if the environment is
2265 embedded within the U-Boot image, or in a separate
2268 - CONFIG_SYS_MALLOC_LEN:
2269 Size of DRAM reserved for malloc() use.
2271 - CONFIG_SYS_BOOTM_LEN:
2272 Normally compressed uImages are limited to an
2273 uncompressed size of 8 MBytes. If this is not enough,
2274 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2275 to adjust this setting to your needs.
2277 - CONFIG_SYS_BOOTMAPSZ:
2278 Maximum size of memory mapped by the startup code of
2279 the Linux kernel; all data that must be processed by
2280 the Linux kernel (bd_info, boot arguments, FDT blob if
2281 used) must be put below this limit, unless "bootm_low"
2282 enviroment variable is defined and non-zero. In such case
2283 all data for the Linux kernel must be between "bootm_low"
2284 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.
2286 - CONFIG_SYS_MAX_FLASH_BANKS:
2287 Max number of Flash memory banks
2289 - CONFIG_SYS_MAX_FLASH_SECT:
2290 Max number of sectors on a Flash chip
2292 - CONFIG_SYS_FLASH_ERASE_TOUT:
2293 Timeout for Flash erase operations (in ms)
2295 - CONFIG_SYS_FLASH_WRITE_TOUT:
2296 Timeout for Flash write operations (in ms)
2298 - CONFIG_SYS_FLASH_LOCK_TOUT
2299 Timeout for Flash set sector lock bit operation (in ms)
2301 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2302 Timeout for Flash clear lock bits operation (in ms)
2304 - CONFIG_SYS_FLASH_PROTECTION
2305 If defined, hardware flash sectors protection is used
2306 instead of U-Boot software protection.
2308 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2310 Enable TFTP transfers directly to flash memory;
2311 without this option such a download has to be
2312 performed in two steps: (1) download to RAM, and (2)
2313 copy from RAM to flash.
2315 The two-step approach is usually more reliable, since
2316 you can check if the download worked before you erase
2317 the flash, but in some situations (when system RAM is
2318 too limited to allow for a temporary copy of the
2319 downloaded image) this option may be very useful.
2321 - CONFIG_SYS_FLASH_CFI:
2322 Define if the flash driver uses extra elements in the
2323 common flash structure for storing flash geometry.
2325 - CONFIG_FLASH_CFI_DRIVER
2326 This option also enables the building of the cfi_flash driver
2327 in the drivers directory
2329 - CONFIG_FLASH_CFI_MTD
2330 This option enables the building of the cfi_mtd driver
2331 in the drivers directory. The driver exports CFI flash
2334 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2335 Use buffered writes to flash.
2337 - CONFIG_FLASH_SPANSION_S29WS_N
2338 s29ws-n MirrorBit flash has non-standard addresses for buffered
2341 - CONFIG_SYS_FLASH_QUIET_TEST
2342 If this option is defined, the common CFI flash doesn't
2343 print it's warning upon not recognized FLASH banks. This
2344 is useful, if some of the configured banks are only
2345 optionally available.
2347 - CONFIG_FLASH_SHOW_PROGRESS
2348 If defined (must be an integer), print out countdown
2349 digits and dots. Recommended value: 45 (9..1) for 80
2350 column displays, 15 (3..1) for 40 column displays.
2352 - CONFIG_SYS_RX_ETH_BUFFER:
2353 Defines the number of Ethernet receive buffers. On some
2354 Ethernet controllers it is recommended to set this value
2355 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2356 buffers can be full shortly after enabling the interface
2357 on high Ethernet traffic.
2358 Defaults to 4 if not defined.
2360 The following definitions that deal with the placement and management
2361 of environment data (variable area); in general, we support the
2362 following configurations:
2364 - CONFIG_ENV_IS_IN_FLASH:
2366 Define this if the environment is in flash memory.
2368 a) The environment occupies one whole flash sector, which is
2369 "embedded" in the text segment with the U-Boot code. This
2370 happens usually with "bottom boot sector" or "top boot
2371 sector" type flash chips, which have several smaller
2372 sectors at the start or the end. For instance, such a
2373 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2374 such a case you would place the environment in one of the
2375 4 kB sectors - with U-Boot code before and after it. With
2376 "top boot sector" type flash chips, you would put the
2377 environment in one of the last sectors, leaving a gap
2378 between U-Boot and the environment.
2380 - CONFIG_ENV_OFFSET:
2382 Offset of environment data (variable area) to the
2383 beginning of flash memory; for instance, with bottom boot
2384 type flash chips the second sector can be used: the offset
2385 for this sector is given here.
2387 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2391 This is just another way to specify the start address of
2392 the flash sector containing the environment (instead of
2395 - CONFIG_ENV_SECT_SIZE:
2397 Size of the sector containing the environment.
2400 b) Sometimes flash chips have few, equal sized, BIG sectors.
2401 In such a case you don't want to spend a whole sector for
2406 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2407 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2408 of this flash sector for the environment. This saves
2409 memory for the RAM copy of the environment.
2411 It may also save flash memory if you decide to use this
2412 when your environment is "embedded" within U-Boot code,
2413 since then the remainder of the flash sector could be used
2414 for U-Boot code. It should be pointed out that this is
2415 STRONGLY DISCOURAGED from a robustness point of view:
2416 updating the environment in flash makes it always
2417 necessary to erase the WHOLE sector. If something goes
2418 wrong before the contents has been restored from a copy in
2419 RAM, your target system will be dead.
2421 - CONFIG_ENV_ADDR_REDUND
2422 CONFIG_ENV_SIZE_REDUND
2424 These settings describe a second storage area used to hold
2425 a redundant copy of the environment data, so that there is
2426 a valid backup copy in case there is a power failure during
2427 a "saveenv" operation.
2429 BE CAREFUL! Any changes to the flash layout, and some changes to the
2430 source code will make it necessary to adapt <board>/u-boot.lds*
2434 - CONFIG_ENV_IS_IN_NVRAM:
2436 Define this if you have some non-volatile memory device
2437 (NVRAM, battery buffered SRAM) which you want to use for the
2443 These two #defines are used to determine the memory area you
2444 want to use for environment. It is assumed that this memory
2445 can just be read and written to, without any special
2448 BE CAREFUL! The first access to the environment happens quite early
2449 in U-Boot initalization (when we try to get the setting of for the
2450 console baudrate). You *MUST* have mapped your NVRAM area then, or
2453 Please note that even with NVRAM we still use a copy of the
2454 environment in RAM: we could work on NVRAM directly, but we want to
2455 keep settings there always unmodified except somebody uses "saveenv"
2456 to save the current settings.
2459 - CONFIG_ENV_IS_IN_EEPROM:
2461 Use this if you have an EEPROM or similar serial access
2462 device and a driver for it.
2464 - CONFIG_ENV_OFFSET:
2467 These two #defines specify the offset and size of the
2468 environment area within the total memory of your EEPROM.
2470 - CONFIG_SYS_I2C_EEPROM_ADDR:
2471 If defined, specified the chip address of the EEPROM device.
2472 The default address is zero.
2474 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2475 If defined, the number of bits used to address bytes in a
2476 single page in the EEPROM device. A 64 byte page, for example
2477 would require six bits.
2479 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2480 If defined, the number of milliseconds to delay between
2481 page writes. The default is zero milliseconds.
2483 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2484 The length in bytes of the EEPROM memory array address. Note
2485 that this is NOT the chip address length!
2487 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2488 EEPROM chips that implement "address overflow" are ones
2489 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2490 address and the extra bits end up in the "chip address" bit
2491 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2494 Note that we consider the length of the address field to
2495 still be one byte because the extra address bits are hidden
2496 in the chip address.
2498 - CONFIG_SYS_EEPROM_SIZE:
2499 The size in bytes of the EEPROM device.
2501 - CONFIG_ENV_EEPROM_IS_ON_I2C
2502 define this, if you have I2C and SPI activated, and your
2503 EEPROM, which holds the environment, is on the I2C bus.
2505 - CONFIG_I2C_ENV_EEPROM_BUS
2506 if you have an Environment on an EEPROM reached over
2507 I2C muxes, you can define here, how to reach this
2508 EEPROM. For example:
2510 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2512 EEPROM which holds the environment, is reached over
2513 a pca9547 i2c mux with address 0x70, channel 3.
2515 - CONFIG_ENV_IS_IN_DATAFLASH:
2517 Define this if you have a DataFlash memory device which you
2518 want to use for the environment.
2520 - CONFIG_ENV_OFFSET:
2524 These three #defines specify the offset and size of the
2525 environment area within the total memory of your DataFlash placed
2526 at the specified address.
2528 - CONFIG_ENV_IS_IN_NAND:
2530 Define this if you have a NAND device which you want to use
2531 for the environment.
2533 - CONFIG_ENV_OFFSET:
2536 These two #defines specify the offset and size of the environment
2537 area within the first NAND device.
2539 - CONFIG_ENV_OFFSET_REDUND
2541 This setting describes a second storage area of CONFIG_ENV_SIZE
2542 size used to hold a redundant copy of the environment data,
2543 so that there is a valid backup copy in case there is a
2544 power failure during a "saveenv" operation.
2546 Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
2547 to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
2548 the NAND devices block size.
2550 - CONFIG_NAND_ENV_DST
2552 Defines address in RAM to which the nand_spl code should copy the
2553 environment. If redundant environment is used, it will be copied to
2554 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2556 - CONFIG_SYS_SPI_INIT_OFFSET
2558 Defines offset to the initial SPI buffer area in DPRAM. The
2559 area is used at an early stage (ROM part) if the environment
2560 is configured to reside in the SPI EEPROM: We need a 520 byte
2561 scratch DPRAM area. It is used between the two initialization
2562 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2563 to be a good choice since it makes it far enough from the
2564 start of the data area as well as from the stack pointer.
2566 Please note that the environment is read-only until the monitor
2567 has been relocated to RAM and a RAM copy of the environment has been
2568 created; also, when using EEPROM you will have to use getenv_r()
2569 until then to read environment variables.
2571 The environment is protected by a CRC32 checksum. Before the monitor
2572 is relocated into RAM, as a result of a bad CRC you will be working
2573 with the compiled-in default environment - *silently*!!! [This is
2574 necessary, because the first environment variable we need is the
2575 "baudrate" setting for the console - if we have a bad CRC, we don't
2576 have any device yet where we could complain.]
2578 Note: once the monitor has been relocated, then it will complain if
2579 the default environment is used; a new CRC is computed as soon as you
2580 use the "saveenv" command to store a valid environment.
2582 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2583 Echo the inverted Ethernet link state to the fault LED.
2585 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2586 also needs to be defined.
2588 - CONFIG_SYS_FAULT_MII_ADDR:
2589 MII address of the PHY to check for the Ethernet link state.
2591 - CONFIG_NS16550_MIN_FUNCTIONS:
2592 Define this if you desire to only have use of the NS16550_init
2593 and NS16550_putc functions for the serial driver located at
2594 drivers/serial/ns16550.c. This option is useful for saving
2595 space for already greatly restricted images, including but not
2596 limited to NAND_SPL configurations.
2598 Low Level (hardware related) configuration options:
2599 ---------------------------------------------------
2601 - CONFIG_SYS_CACHELINE_SIZE:
2602 Cache Line Size of the CPU.
2604 - CONFIG_SYS_DEFAULT_IMMR:
2605 Default address of the IMMR after system reset.
2607 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2608 and RPXsuper) to be able to adjust the position of
2609 the IMMR register after a reset.
2611 - Floppy Disk Support:
2612 CONFIG_SYS_FDC_DRIVE_NUMBER
2614 the default drive number (default value 0)
2616 CONFIG_SYS_ISA_IO_STRIDE
2618 defines the spacing between FDC chipset registers
2621 CONFIG_SYS_ISA_IO_OFFSET
2623 defines the offset of register from address. It
2624 depends on which part of the data bus is connected to
2625 the FDC chipset. (default value 0)
2627 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2628 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2631 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2632 fdc_hw_init() is called at the beginning of the FDC
2633 setup. fdc_hw_init() must be provided by the board
2634 source code. It is used to make hardware dependant
2637 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
2638 DO NOT CHANGE unless you know exactly what you're
2639 doing! (11-4) [MPC8xx/82xx systems only]
2641 - CONFIG_SYS_INIT_RAM_ADDR:
2643 Start address of memory area that can be used for
2644 initial data and stack; please note that this must be
2645 writable memory that is working WITHOUT special
2646 initialization, i. e. you CANNOT use normal RAM which
2647 will become available only after programming the
2648 memory controller and running certain initialization
2651 U-Boot uses the following memory types:
2652 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2653 - MPC824X: data cache
2654 - PPC4xx: data cache
2656 - CONFIG_SYS_GBL_DATA_OFFSET:
2658 Offset of the initial data structure in the memory
2659 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
2660 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
2661 data is located at the end of the available space
2662 (sometimes written as (CONFIG_SYS_INIT_RAM_END -
2663 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
2664 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
2665 CONFIG_SYS_GBL_DATA_OFFSET) downward.
2668 On the MPC824X (or other systems that use the data
2669 cache for initial memory) the address chosen for
2670 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
2671 point to an otherwise UNUSED address space between
2672 the top of RAM and the start of the PCI space.
2674 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
2676 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
2678 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
2680 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
2682 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2684 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
2686 - CONFIG_SYS_OR_TIMING_SDRAM:
2689 - CONFIG_SYS_MAMR_PTA:
2690 periodic timer for refresh
2692 - CONFIG_SYS_DER: Debug Event Register (37-47)
2694 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
2695 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
2696 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
2697 CONFIG_SYS_BR1_PRELIM:
2698 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2700 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2701 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
2702 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
2703 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2705 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
2706 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
2707 Machine Mode Register and Memory Periodic Timer
2708 Prescaler definitions (SDRAM timing)
2710 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
2711 enable I2C microcode relocation patch (MPC8xx);
2712 define relocation offset in DPRAM [DSP2]
2714 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
2715 enable SMC microcode relocation patch (MPC8xx);
2716 define relocation offset in DPRAM [SMC1]
2718 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
2719 enable SPI microcode relocation patch (MPC8xx);
2720 define relocation offset in DPRAM [SCC4]
2722 - CONFIG_SYS_USE_OSCCLK:
2723 Use OSCM clock mode on MBX8xx board. Be careful,
2724 wrong setting might damage your board. Read
2725 doc/README.MBX before setting this variable!
2727 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2728 Offset of the bootmode word in DPRAM used by post
2729 (Power On Self Tests). This definition overrides
2730 #define'd default value in commproc.h resp.
2733 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
2734 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
2735 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
2736 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
2737 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2738 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
2739 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
2740 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
2741 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
2743 - CONFIG_PCI_DISABLE_PCIE:
2744 Disable PCI-Express on systems where it is supported but not
2748 Get DDR timing information from an I2C EEPROM. Common
2749 with pluggable memory modules such as SODIMMs
2752 I2C address of the SPD EEPROM
2754 - CONFIG_SYS_SPD_BUS_NUM
2755 If SPD EEPROM is on an I2C bus other than the first
2756 one, specify here. Note that the value must resolve
2757 to something your driver can deal with.
2759 - CONFIG_SYS_83XX_DDR_USES_CS0
2760 Only for 83xx systems. If specified, then DDR should
2761 be configured using CS0 and CS1 instead of CS2 and CS3.
2763 - CONFIG_ETHER_ON_FEC[12]
2764 Define to enable FEC[12] on a 8xx series processor.
2766 - CONFIG_FEC[12]_PHY
2767 Define to the hardcoded PHY address which corresponds
2768 to the given FEC; i. e.
2769 #define CONFIG_FEC1_PHY 4
2770 means that the PHY with address 4 is connected to FEC1
2772 When set to -1, means to probe for first available.
2774 - CONFIG_FEC[12]_PHY_NORXERR
2775 The PHY does not have a RXERR line (RMII only).
2776 (so program the FEC to ignore it).
2779 Enable RMII mode for all FECs.
2780 Note that this is a global option, we can't
2781 have one FEC in standard MII mode and another in RMII mode.
2783 - CONFIG_CRC32_VERIFY
2784 Add a verify option to the crc32 command.
2787 => crc32 -v <address> <count> <crc32>
2789 Where address/count indicate a memory area
2790 and crc32 is the correct crc32 which the
2794 Add the "loopw" memory command. This only takes effect if
2795 the memory commands are activated globally (CONFIG_CMD_MEM).
2798 Add the "mdc" and "mwc" memory commands. These are cyclic
2803 This command will print 4 bytes (10,11,12,13) each 500 ms.
2805 => mwc.l 100 12345678 10
2806 This command will write 12345678 to address 100 all 10 ms.
2808 This only takes effect if the memory commands are activated
2809 globally (CONFIG_CMD_MEM).
2811 - CONFIG_SKIP_LOWLEVEL_INIT
2812 - CONFIG_SKIP_RELOCATE_UBOOT
2814 [ARM only] If these variables are defined, then
2815 certain low level initializations (like setting up
2816 the memory controller) are omitted and/or U-Boot does
2817 not relocate itself into RAM.
2818 Normally these variables MUST NOT be defined. The
2819 only exception is when U-Boot is loaded (to RAM) by
2820 some other boot loader or by a debugger which
2821 performs these initializations itself.
2825 Modifies the behaviour of start.S when compiling a loader
2826 that is executed before the actual U-Boot. E.g. when
2827 compiling a NAND SPL.
2829 Building the Software:
2830 ======================
2832 Building U-Boot has been tested in several native build environments
2833 and in many different cross environments. Of course we cannot support
2834 all possibly existing versions of cross development tools in all
2835 (potentially obsolete) versions. In case of tool chain problems we
2836 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2837 which is extensively used to build and test U-Boot.
2839 If you are not using a native environment, it is assumed that you
2840 have GNU cross compiling tools available in your path. In this case,
2841 you must set the environment variable CROSS_COMPILE in your shell.
2842 Note that no changes to the Makefile or any other source files are
2843 necessary. For example using the ELDK on a 4xx CPU, please enter:
2845 $ CROSS_COMPILE=ppc_4xx-
2846 $ export CROSS_COMPILE
2848 Note: If you wish to generate Windows versions of the utilities in
2849 the tools directory you can use the MinGW toolchain
2850 (http://www.mingw.org). Set your HOST tools to the MinGW
2851 toolchain and execute 'make tools'. For example:
2853 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
2855 Binaries such as tools/mkimage.exe will be created which can
2856 be executed on computers running Windows.
2858 U-Boot is intended to be simple to build. After installing the
2859 sources you must configure U-Boot for one specific board type. This
2864 where "NAME_config" is the name of one of the existing configu-
2865 rations; see the main Makefile for supported names.
2867 Note: for some board special configuration names may exist; check if
2868 additional information is available from the board vendor; for
2869 instance, the TQM823L systems are available without (standard)
2870 or with LCD support. You can select such additional "features"
2871 when choosing the configuration, i. e.
2874 - will configure for a plain TQM823L, i. e. no LCD support
2876 make TQM823L_LCD_config
2877 - will configure for a TQM823L with U-Boot console on LCD
2882 Finally, type "make all", and you should get some working U-Boot
2883 images ready for download to / installation on your system:
2885 - "u-boot.bin" is a raw binary image
2886 - "u-boot" is an image in ELF binary format
2887 - "u-boot.srec" is in Motorola S-Record format
2889 By default the build is performed locally and the objects are saved
2890 in the source directory. One of the two methods can be used to change
2891 this behavior and build U-Boot to some external directory:
2893 1. Add O= to the make command line invocations:
2895 make O=/tmp/build distclean
2896 make O=/tmp/build NAME_config
2897 make O=/tmp/build all
2899 2. Set environment variable BUILD_DIR to point to the desired location:
2901 export BUILD_DIR=/tmp/build
2906 Note that the command line "O=" setting overrides the BUILD_DIR environment
2910 Please be aware that the Makefiles assume you are using GNU make, so
2911 for instance on NetBSD you might need to use "gmake" instead of
2915 If the system board that you have is not listed, then you will need
2916 to port U-Boot to your hardware platform. To do this, follow these
2919 1. Add a new configuration option for your board to the toplevel
2920 "Makefile" and to the "MAKEALL" script, using the existing
2921 entries as examples. Note that here and at many other places
2922 boards and other names are listed in alphabetical sort order. Please
2924 2. Create a new directory to hold your board specific code. Add any
2925 files you need. In your board directory, you will need at least
2926 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2927 3. Create a new configuration file "include/configs/<board>.h" for
2929 3. If you're porting U-Boot to a new CPU, then also create a new
2930 directory to hold your CPU specific code. Add any files you need.
2931 4. Run "make <board>_config" with your new name.
2932 5. Type "make", and you should get a working "u-boot.srec" file
2933 to be installed on your target system.
2934 6. Debug and solve any problems that might arise.
2935 [Of course, this last step is much harder than it sounds.]
2938 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2939 ==============================================================
2941 If you have modified U-Boot sources (for instance added a new board
2942 or support for new devices, a new CPU, etc.) you are expected to
2943 provide feedback to the other developers. The feedback normally takes
2944 the form of a "patch", i. e. a context diff against a certain (latest
2945 official or latest in the git repository) version of U-Boot sources.
2947 But before you submit such a patch, please verify that your modifi-
2948 cation did not break existing code. At least make sure that *ALL* of
2949 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2950 just run the "MAKEALL" script, which will configure and build U-Boot
2951 for ALL supported system. Be warned, this will take a while. You can
2952 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2953 environment variable to the script, i. e. to use the ELDK cross tools
2956 CROSS_COMPILE=ppc_8xx- MAKEALL
2958 or to build on a native PowerPC system you can type
2960 CROSS_COMPILE=' ' MAKEALL
2962 When using the MAKEALL script, the default behaviour is to build
2963 U-Boot in the source directory. This location can be changed by
2964 setting the BUILD_DIR environment variable. Also, for each target
2965 built, the MAKEALL script saves two log files (<target>.ERR and
2966 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2967 location can be changed by setting the MAKEALL_LOGDIR environment
2968 variable. For example:
2970 export BUILD_DIR=/tmp/build
2971 export MAKEALL_LOGDIR=/tmp/log
2972 CROSS_COMPILE=ppc_8xx- MAKEALL
2974 With the above settings build objects are saved in the /tmp/build,
2975 log files are saved in the /tmp/log and the source tree remains clean
2976 during the whole build process.
2979 See also "U-Boot Porting Guide" below.
2982 Monitor Commands - Overview:
2983 ============================
2985 go - start application at address 'addr'
2986 run - run commands in an environment variable
2987 bootm - boot application image from memory
2988 bootp - boot image via network using BootP/TFTP protocol
2989 tftpboot- boot image via network using TFTP protocol
2990 and env variables "ipaddr" and "serverip"
2991 (and eventually "gatewayip")
2992 rarpboot- boot image via network using RARP/TFTP protocol
2993 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2994 loads - load S-Record file over serial line
2995 loadb - load binary file over serial line (kermit mode)
2997 mm - memory modify (auto-incrementing)
2998 nm - memory modify (constant address)
2999 mw - memory write (fill)
3001 cmp - memory compare
3002 crc32 - checksum calculation
3003 i2c - I2C sub-system
3004 sspi - SPI utility commands
3005 base - print or set address offset
3006 printenv- print environment variables
3007 setenv - set environment variables
3008 saveenv - save environment variables to persistent storage
3009 protect - enable or disable FLASH write protection
3010 erase - erase FLASH memory
3011 flinfo - print FLASH memory information
3012 bdinfo - print Board Info structure
3013 iminfo - print header information for application image
3014 coninfo - print console devices and informations
3015 ide - IDE sub-system
3016 loop - infinite loop on address range
3017 loopw - infinite write loop on address range
3018 mtest - simple RAM test
3019 icache - enable or disable instruction cache
3020 dcache - enable or disable data cache
3021 reset - Perform RESET of the CPU
3022 echo - echo args to console
3023 version - print monitor version
3024 help - print online help
3025 ? - alias for 'help'
3028 Monitor Commands - Detailed Description:
3029 ========================================
3033 For now: just type "help <command>".
3036 Environment Variables:
3037 ======================
3039 U-Boot supports user configuration using Environment Variables which
3040 can be made persistent by saving to Flash memory.
3042 Environment Variables are set using "setenv", printed using
3043 "printenv", and saved to Flash using "saveenv". Using "setenv"
3044 without a value can be used to delete a variable from the
3045 environment. As long as you don't save the environment you are
3046 working with an in-memory copy. In case the Flash area containing the
3047 environment is erased by accident, a default environment is provided.
3049 Some configuration options can be set using Environment Variables.
3051 List of environment variables (most likely not complete):
3053 baudrate - see CONFIG_BAUDRATE
3055 bootdelay - see CONFIG_BOOTDELAY
3057 bootcmd - see CONFIG_BOOTCOMMAND
3059 bootargs - Boot arguments when booting an RTOS image
3061 bootfile - Name of the image to load with TFTP
3063 bootm_low - Memory range available for image processing in the bootm
3064 command can be restricted. This variable is given as
3065 a hexadecimal number and defines lowest address allowed
3066 for use by the bootm command. See also "bootm_size"
3067 environment variable. Address defined by "bootm_low" is
3068 also the base of the initial memory mapping for the Linux
3069 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ.
3071 bootm_size - Memory range available for image processing in the bootm
3072 command can be restricted. This variable is given as
3073 a hexadecimal number and defines the size of the region
3074 allowed for use by the bootm command. See also "bootm_low"
3075 environment variable.
3077 updatefile - Location of the software update file on a TFTP server, used
3078 by the automatic software update feature. Please refer to
3079 documentation in doc/README.update for more details.
3081 autoload - if set to "no" (any string beginning with 'n'),
3082 "bootp" will just load perform a lookup of the
3083 configuration from the BOOTP server, but not try to
3084 load any image using TFTP
3086 autostart - if set to "yes", an image loaded using the "bootp",
3087 "rarpboot", "tftpboot" or "diskboot" commands will
3088 be automatically started (by internally calling
3091 If set to "no", a standalone image passed to the
3092 "bootm" command will be copied to the load address
3093 (and eventually uncompressed), but NOT be started.
3094 This can be used to load and uncompress arbitrary
3097 i2cfast - (PPC405GP|PPC405EP only)
3098 if set to 'y' configures Linux I2C driver for fast
3099 mode (400kHZ). This environment variable is used in
3100 initialization code. So, for changes to be effective
3101 it must be saved and board must be reset.
3103 initrd_high - restrict positioning of initrd images:
3104 If this variable is not set, initrd images will be
3105 copied to the highest possible address in RAM; this
3106 is usually what you want since it allows for
3107 maximum initrd size. If for some reason you want to
3108 make sure that the initrd image is loaded below the
3109 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3110 variable to a value of "no" or "off" or "0".
3111 Alternatively, you can set it to a maximum upper
3112 address to use (U-Boot will still check that it
3113 does not overwrite the U-Boot stack and data).
3115 For instance, when you have a system with 16 MB
3116 RAM, and want to reserve 4 MB from use by Linux,
3117 you can do this by adding "mem=12M" to the value of
3118 the "bootargs" variable. However, now you must make
3119 sure that the initrd image is placed in the first
3120 12 MB as well - this can be done with
3122 setenv initrd_high 00c00000
3124 If you set initrd_high to 0xFFFFFFFF, this is an
3125 indication to U-Boot that all addresses are legal
3126 for the Linux kernel, including addresses in flash
3127 memory. In this case U-Boot will NOT COPY the
3128 ramdisk at all. This may be useful to reduce the
3129 boot time on your system, but requires that this
3130 feature is supported by your Linux kernel.
3132 ipaddr - IP address; needed for tftpboot command
3134 loadaddr - Default load address for commands like "bootp",
3135 "rarpboot", "tftpboot", "loadb" or "diskboot"
3137 loads_echo - see CONFIG_LOADS_ECHO
3139 serverip - TFTP server IP address; needed for tftpboot command
3141 bootretry - see CONFIG_BOOT_RETRY_TIME
3143 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3145 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3147 ethprime - When CONFIG_NET_MULTI is enabled controls which
3148 interface is used first.
3150 ethact - When CONFIG_NET_MULTI is enabled controls which
3151 interface is currently active. For example you
3152 can do the following
3154 => setenv ethact FEC ETHERNET
3155 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
3156 => setenv ethact SCC ETHERNET
3157 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
3159 ethrotate - When set to "no" U-Boot does not go through all
3160 available network interfaces.
3161 It just stays at the currently selected interface.
3163 netretry - When set to "no" each network operation will
3164 either succeed or fail without retrying.
3165 When set to "once" the network operation will
3166 fail when all the available network interfaces
3167 are tried once without success.
3168 Useful on scripts which control the retry operation
3171 npe_ucode - set load address for the NPE microcode
3173 tftpsrcport - If this is set, the value is used for TFTP's
3176 tftpdstport - If this is set, the value is used for TFTP's UDP
3177 destination port instead of the Well Know Port 69.
3179 tftpblocksize - Block size to use for TFTP transfers; if not set,
3180 we use the TFTP server's default block size
3182 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3183 seconds, minimum value is 1000 = 1 second). Defines
3184 when a packet is considered to be lost so it has to
3185 be retransmitted. The default is 5000 = 5 seconds.
3186 Lowering this value may make downloads succeed
3187 faster in networks with high packet loss rates or
3188 with unreliable TFTP servers.
3190 vlan - When set to a value < 4095 the traffic over
3191 Ethernet is encapsulated/received over 802.1q
3194 The following environment variables may be used and automatically
3195 updated by the network boot commands ("bootp" and "rarpboot"),
3196 depending the information provided by your boot server:
3198 bootfile - see above
3199 dnsip - IP address of your Domain Name Server
3200 dnsip2 - IP address of your secondary Domain Name Server
3201 gatewayip - IP address of the Gateway (Router) to use
3202 hostname - Target hostname
3204 netmask - Subnet Mask
3205 rootpath - Pathname of the root filesystem on the NFS server
3206 serverip - see above
3209 There are two special Environment Variables:
3211 serial# - contains hardware identification information such
3212 as type string and/or serial number
3213 ethaddr - Ethernet address
3215 These variables can be set only once (usually during manufacturing of
3216 the board). U-Boot refuses to delete or overwrite these variables
3217 once they have been set once.
3220 Further special Environment Variables:
3222 ver - Contains the U-Boot version string as printed
3223 with the "version" command. This variable is
3224 readonly (see CONFIG_VERSION_VARIABLE).
3227 Please note that changes to some configuration parameters may take
3228 only effect after the next boot (yes, that's just like Windoze :-).
3231 Command Line Parsing:
3232 =====================
3234 There are two different command line parsers available with U-Boot:
3235 the old "simple" one, and the much more powerful "hush" shell:
3237 Old, simple command line parser:
3238 --------------------------------
3240 - supports environment variables (through setenv / saveenv commands)
3241 - several commands on one line, separated by ';'
3242 - variable substitution using "... ${name} ..." syntax
3243 - special characters ('$', ';') can be escaped by prefixing with '\',
3245 setenv bootcmd bootm \${address}
3246 - You can also escape text by enclosing in single apostrophes, for example:
3247 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3252 - similar to Bourne shell, with control structures like
3253 if...then...else...fi, for...do...done; while...do...done,
3254 until...do...done, ...
3255 - supports environment ("global") variables (through setenv / saveenv
3256 commands) and local shell variables (through standard shell syntax
3257 "name=value"); only environment variables can be used with "run"
3263 (1) If a command line (or an environment variable executed by a "run"
3264 command) contains several commands separated by semicolon, and
3265 one of these commands fails, then the remaining commands will be
3268 (2) If you execute several variables with one call to run (i. e.
3269 calling run with a list of variables as arguments), any failing
3270 command will cause "run" to terminate, i. e. the remaining
3271 variables are not executed.
3273 Note for Redundant Ethernet Interfaces:
3274 =======================================
3276 Some boards come with redundant Ethernet interfaces; U-Boot supports
3277 such configurations and is capable of automatic selection of a
3278 "working" interface when needed. MAC assignment works as follows:
3280 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3281 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3282 "eth1addr" (=>eth1), "eth2addr", ...
3284 If the network interface stores some valid MAC address (for instance
3285 in SROM), this is used as default address if there is NO correspon-
3286 ding setting in the environment; if the corresponding environment
3287 variable is set, this overrides the settings in the card; that means:
3289 o If the SROM has a valid MAC address, and there is no address in the
3290 environment, the SROM's address is used.
3292 o If there is no valid address in the SROM, and a definition in the
3293 environment exists, then the value from the environment variable is
3296 o If both the SROM and the environment contain a MAC address, and
3297 both addresses are the same, this MAC address is used.
3299 o If both the SROM and the environment contain a MAC address, and the
3300 addresses differ, the value from the environment is used and a
3303 o If neither SROM nor the environment contain a MAC address, an error
3310 U-Boot is capable of booting (and performing other auxiliary operations on)
3311 images in two formats:
3313 New uImage format (FIT)
3314 -----------------------
3316 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3317 to Flattened Device Tree). It allows the use of images with multiple
3318 components (several kernels, ramdisks, etc.), with contents protected by
3319 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3325 Old image format is based on binary files which can be basically anything,
3326 preceded by a special header; see the definitions in include/image.h for
3327 details; basically, the header defines the following image properties:
3329 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3330 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3331 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3332 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3334 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3335 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3336 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3337 * Compression Type (uncompressed, gzip, bzip2)
3343 The header is marked by a special Magic Number, and both the header
3344 and the data portions of the image are secured against corruption by
3351 Although U-Boot should support any OS or standalone application
3352 easily, the main focus has always been on Linux during the design of
3355 U-Boot includes many features that so far have been part of some
3356 special "boot loader" code within the Linux kernel. Also, any
3357 "initrd" images to be used are no longer part of one big Linux image;
3358 instead, kernel and "initrd" are separate images. This implementation
3359 serves several purposes:
3361 - the same features can be used for other OS or standalone
3362 applications (for instance: using compressed images to reduce the
3363 Flash memory footprint)
3365 - it becomes much easier to port new Linux kernel versions because
3366 lots of low-level, hardware dependent stuff are done by U-Boot
3368 - the same Linux kernel image can now be used with different "initrd"
3369 images; of course this also means that different kernel images can
3370 be run with the same "initrd". This makes testing easier (you don't
3371 have to build a new "zImage.initrd" Linux image when you just
3372 change a file in your "initrd"). Also, a field-upgrade of the
3373 software is easier now.
3379 Porting Linux to U-Boot based systems:
3380 ---------------------------------------
3382 U-Boot cannot save you from doing all the necessary modifications to
3383 configure the Linux device drivers for use with your target hardware
3384 (no, we don't intend to provide a full virtual machine interface to
3387 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3389 Just make sure your machine specific header file (for instance
3390 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3391 Information structure as we define in include/asm-<arch>/u-boot.h,
3392 and make sure that your definition of IMAP_ADDR uses the same value
3393 as your U-Boot configuration in CONFIG_SYS_IMMR.
3396 Configuring the Linux kernel:
3397 -----------------------------
3399 No specific requirements for U-Boot. Make sure you have some root
3400 device (initial ramdisk, NFS) for your target system.
3403 Building a Linux Image:
3404 -----------------------
3406 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3407 not used. If you use recent kernel source, a new build target
3408 "uImage" will exist which automatically builds an image usable by
3409 U-Boot. Most older kernels also have support for a "pImage" target,
3410 which was introduced for our predecessor project PPCBoot and uses a
3411 100% compatible format.
3420 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3421 encapsulate a compressed Linux kernel image with header information,
3422 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3424 * build a standard "vmlinux" kernel image (in ELF binary format):
3426 * convert the kernel into a raw binary image:
3428 ${CROSS_COMPILE}-objcopy -O binary \
3429 -R .note -R .comment \
3430 -S vmlinux linux.bin
3432 * compress the binary image:
3436 * package compressed binary image for U-Boot:
3438 mkimage -A ppc -O linux -T kernel -C gzip \
3439 -a 0 -e 0 -n "Linux Kernel Image" \
3440 -d linux.bin.gz uImage
3443 The "mkimage" tool can also be used to create ramdisk images for use
3444 with U-Boot, either separated from the Linux kernel image, or
3445 combined into one file. "mkimage" encapsulates the images with a 64
3446 byte header containing information about target architecture,
3447 operating system, image type, compression method, entry points, time
3448 stamp, CRC32 checksums, etc.
3450 "mkimage" can be called in two ways: to verify existing images and
3451 print the header information, or to build new images.
3453 In the first form (with "-l" option) mkimage lists the information
3454 contained in the header of an existing U-Boot image; this includes
3455 checksum verification:
3457 tools/mkimage -l image
3458 -l ==> list image header information
3460 The second form (with "-d" option) is used to build a U-Boot image
3461 from a "data file" which is used as image payload:
3463 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3464 -n name -d data_file image
3465 -A ==> set architecture to 'arch'
3466 -O ==> set operating system to 'os'
3467 -T ==> set image type to 'type'
3468 -C ==> set compression type 'comp'
3469 -a ==> set load address to 'addr' (hex)
3470 -e ==> set entry point to 'ep' (hex)
3471 -n ==> set image name to 'name'
3472 -d ==> use image data from 'datafile'
3474 Right now, all Linux kernels for PowerPC systems use the same load
3475 address (0x00000000), but the entry point address depends on the
3478 - 2.2.x kernels have the entry point at 0x0000000C,
3479 - 2.3.x and later kernels have the entry point at 0x00000000.
3481 So a typical call to build a U-Boot image would read:
3483 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3484 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3485 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3486 > examples/uImage.TQM850L
3487 Image Name: 2.4.4 kernel for TQM850L
3488 Created: Wed Jul 19 02:34:59 2000
3489 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3490 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3491 Load Address: 0x00000000
3492 Entry Point: 0x00000000
3494 To verify the contents of the image (or check for corruption):
3496 -> tools/mkimage -l examples/uImage.TQM850L
3497 Image Name: 2.4.4 kernel for TQM850L
3498 Created: Wed Jul 19 02:34:59 2000
3499 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3500 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3501 Load Address: 0x00000000
3502 Entry Point: 0x00000000
3504 NOTE: for embedded systems where boot time is critical you can trade
3505 speed for memory and install an UNCOMPRESSED image instead: this
3506 needs more space in Flash, but boots much faster since it does not
3507 need to be uncompressed:
3509 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3510 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3511 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3512 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3513 > examples/uImage.TQM850L-uncompressed
3514 Image Name: 2.4.4 kernel for TQM850L
3515 Created: Wed Jul 19 02:34:59 2000
3516 Image Type: PowerPC Linux Kernel Image (uncompressed)
3517 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3518 Load Address: 0x00000000
3519 Entry Point: 0x00000000
3522 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3523 when your kernel is intended to use an initial ramdisk:
3525 -> tools/mkimage -n 'Simple Ramdisk Image' \
3526 > -A ppc -O linux -T ramdisk -C gzip \
3527 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3528 Image Name: Simple Ramdisk Image
3529 Created: Wed Jan 12 14:01:50 2000
3530 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3531 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3532 Load Address: 0x00000000
3533 Entry Point: 0x00000000
3536 Installing a Linux Image:
3537 -------------------------
3539 To downloading a U-Boot image over the serial (console) interface,
3540 you must convert the image to S-Record format:
3542 objcopy -I binary -O srec examples/image examples/image.srec
3544 The 'objcopy' does not understand the information in the U-Boot
3545 image header, so the resulting S-Record file will be relative to
3546 address 0x00000000. To load it to a given address, you need to
3547 specify the target address as 'offset' parameter with the 'loads'
3550 Example: install the image to address 0x40100000 (which on the
3551 TQM8xxL is in the first Flash bank):
3553 => erase 40100000 401FFFFF
3559 ## Ready for S-Record download ...
3560 ~>examples/image.srec
3561 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3563 15989 15990 15991 15992
3564 [file transfer complete]
3566 ## Start Addr = 0x00000000
3569 You can check the success of the download using the 'iminfo' command;
3570 this includes a checksum verification so you can be sure no data
3571 corruption happened:
3575 ## Checking Image at 40100000 ...
3576 Image Name: 2.2.13 for initrd on TQM850L
3577 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3578 Data Size: 335725 Bytes = 327 kB = 0 MB
3579 Load Address: 00000000
3580 Entry Point: 0000000c
3581 Verifying Checksum ... OK
3587 The "bootm" command is used to boot an application that is stored in
3588 memory (RAM or Flash). In case of a Linux kernel image, the contents
3589 of the "bootargs" environment variable is passed to the kernel as
3590 parameters. You can check and modify this variable using the
3591 "printenv" and "setenv" commands:
3594 => printenv bootargs
3595 bootargs=root=/dev/ram
3597 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3599 => printenv bootargs
3600 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3603 ## Booting Linux kernel at 40020000 ...
3604 Image Name: 2.2.13 for NFS on TQM850L
3605 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3606 Data Size: 381681 Bytes = 372 kB = 0 MB
3607 Load Address: 00000000
3608 Entry Point: 0000000c
3609 Verifying Checksum ... OK
3610 Uncompressing Kernel Image ... OK
3611 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
3612 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3613 time_init: decrementer frequency = 187500000/60
3614 Calibrating delay loop... 49.77 BogoMIPS
3615 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3618 If you want to boot a Linux kernel with initial RAM disk, you pass
3619 the memory addresses of both the kernel and the initrd image (PPBCOOT
3620 format!) to the "bootm" command:
3622 => imi 40100000 40200000
3624 ## Checking Image at 40100000 ...
3625 Image Name: 2.2.13 for initrd on TQM850L
3626 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3627 Data Size: 335725 Bytes = 327 kB = 0 MB
3628 Load Address: 00000000
3629 Entry Point: 0000000c
3630 Verifying Checksum ... OK
3632 ## Checking Image at 40200000 ...
3633 Image Name: Simple Ramdisk Image
3634 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3635 Data Size: 566530 Bytes = 553 kB = 0 MB
3636 Load Address: 00000000
3637 Entry Point: 00000000
3638 Verifying Checksum ... OK
3640 => bootm 40100000 40200000
3641 ## Booting Linux kernel at 40100000 ...
3642 Image Name: 2.2.13 for initrd on TQM850L
3643 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3644 Data Size: 335725 Bytes = 327 kB = 0 MB
3645 Load Address: 00000000
3646 Entry Point: 0000000c
3647 Verifying Checksum ... OK
3648 Uncompressing Kernel Image ... OK
3649 ## Loading RAMDisk Image at 40200000 ...
3650 Image Name: Simple Ramdisk Image
3651 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3652 Data Size: 566530 Bytes = 553 kB = 0 MB
3653 Load Address: 00000000
3654 Entry Point: 00000000
3655 Verifying Checksum ... OK
3656 Loading Ramdisk ... OK
3657 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
3658 Boot arguments: root=/dev/ram
3659 time_init: decrementer frequency = 187500000/60
3660 Calibrating delay loop... 49.77 BogoMIPS
3662 RAMDISK: Compressed image found at block 0
3663 VFS: Mounted root (ext2 filesystem).
3667 Boot Linux and pass a flat device tree:
3670 First, U-Boot must be compiled with the appropriate defines. See the section
3671 titled "Linux Kernel Interface" above for a more in depth explanation. The
3672 following is an example of how to start a kernel and pass an updated
3678 oft=oftrees/mpc8540ads.dtb
3679 => tftp $oftaddr $oft
3680 Speed: 1000, full duplex
3682 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3683 Filename 'oftrees/mpc8540ads.dtb'.
3684 Load address: 0x300000
3687 Bytes transferred = 4106 (100a hex)
3688 => tftp $loadaddr $bootfile
3689 Speed: 1000, full duplex
3691 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3693 Load address: 0x200000
3694 Loading:############
3696 Bytes transferred = 1029407 (fb51f hex)
3701 => bootm $loadaddr - $oftaddr
3702 ## Booting image at 00200000 ...
3703 Image Name: Linux-2.6.17-dirty
3704 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3705 Data Size: 1029343 Bytes = 1005.2 kB
3706 Load Address: 00000000
3707 Entry Point: 00000000
3708 Verifying Checksum ... OK
3709 Uncompressing Kernel Image ... OK
3710 Booting using flat device tree at 0x300000
3711 Using MPC85xx ADS machine description
3712 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3716 More About U-Boot Image Types:
3717 ------------------------------
3719 U-Boot supports the following image types:
3721 "Standalone Programs" are directly runnable in the environment
3722 provided by U-Boot; it is expected that (if they behave
3723 well) you can continue to work in U-Boot after return from
3724 the Standalone Program.
3725 "OS Kernel Images" are usually images of some Embedded OS which
3726 will take over control completely. Usually these programs
3727 will install their own set of exception handlers, device
3728 drivers, set up the MMU, etc. - this means, that you cannot
3729 expect to re-enter U-Boot except by resetting the CPU.
3730 "RAMDisk Images" are more or less just data blocks, and their
3731 parameters (address, size) are passed to an OS kernel that is
3733 "Multi-File Images" contain several images, typically an OS
3734 (Linux) kernel image and one or more data images like
3735 RAMDisks. This construct is useful for instance when you want
3736 to boot over the network using BOOTP etc., where the boot
3737 server provides just a single image file, but you want to get
3738 for instance an OS kernel and a RAMDisk image.
3740 "Multi-File Images" start with a list of image sizes, each
3741 image size (in bytes) specified by an "uint32_t" in network
3742 byte order. This list is terminated by an "(uint32_t)0".
3743 Immediately after the terminating 0 follow the images, one by
3744 one, all aligned on "uint32_t" boundaries (size rounded up to
3745 a multiple of 4 bytes).
3747 "Firmware Images" are binary images containing firmware (like
3748 U-Boot or FPGA images) which usually will be programmed to
3751 "Script files" are command sequences that will be executed by
3752 U-Boot's command interpreter; this feature is especially
3753 useful when you configure U-Boot to use a real shell (hush)
3754 as command interpreter.
3760 One of the features of U-Boot is that you can dynamically load and
3761 run "standalone" applications, which can use some resources of
3762 U-Boot like console I/O functions or interrupt services.
3764 Two simple examples are included with the sources:
3769 'examples/hello_world.c' contains a small "Hello World" Demo
3770 application; it is automatically compiled when you build U-Boot.
3771 It's configured to run at address 0x00040004, so you can play with it
3775 ## Ready for S-Record download ...
3776 ~>examples/hello_world.srec
3777 1 2 3 4 5 6 7 8 9 10 11 ...
3778 [file transfer complete]
3780 ## Start Addr = 0x00040004
3782 => go 40004 Hello World! This is a test.
3783 ## Starting application at 0x00040004 ...
3794 Hit any key to exit ...
3796 ## Application terminated, rc = 0x0
3798 Another example, which demonstrates how to register a CPM interrupt
3799 handler with the U-Boot code, can be found in 'examples/timer.c'.
3800 Here, a CPM timer is set up to generate an interrupt every second.
3801 The interrupt service routine is trivial, just printing a '.'
3802 character, but this is just a demo program. The application can be
3803 controlled by the following keys:
3805 ? - print current values og the CPM Timer registers
3806 b - enable interrupts and start timer
3807 e - stop timer and disable interrupts
3808 q - quit application
3811 ## Ready for S-Record download ...
3812 ~>examples/timer.srec
3813 1 2 3 4 5 6 7 8 9 10 11 ...
3814 [file transfer complete]
3816 ## Start Addr = 0x00040004
3819 ## Starting application at 0x00040004 ...
3822 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3825 [q, b, e, ?] Set interval 1000000 us
3828 [q, b, e, ?] ........
3829 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3832 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3835 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3838 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3840 [q, b, e, ?] ...Stopping timer
3842 [q, b, e, ?] ## Application terminated, rc = 0x0
3848 Over time, many people have reported problems when trying to use the
3849 "minicom" terminal emulation program for serial download. I (wd)
3850 consider minicom to be broken, and recommend not to use it. Under
3851 Unix, I recommend to use C-Kermit for general purpose use (and
3852 especially for kermit binary protocol download ("loadb" command), and
3853 use "cu" for S-Record download ("loads" command).
3855 Nevertheless, if you absolutely want to use it try adding this
3856 configuration to your "File transfer protocols" section:
3858 Name Program Name U/D FullScr IO-Red. Multi
3859 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3860 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3866 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3867 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3869 Building requires a cross environment; it is known to work on
3870 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3871 need gmake since the Makefiles are not compatible with BSD make).
3872 Note that the cross-powerpc package does not install include files;
3873 attempting to build U-Boot will fail because <machine/ansi.h> is
3874 missing. This file has to be installed and patched manually:
3876 # cd /usr/pkg/cross/powerpc-netbsd/include
3878 # ln -s powerpc machine
3879 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3880 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3882 Native builds *don't* work due to incompatibilities between native
3883 and U-Boot include files.
3885 Booting assumes that (the first part of) the image booted is a
3886 stage-2 loader which in turn loads and then invokes the kernel
3887 proper. Loader sources will eventually appear in the NetBSD source
3888 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3889 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3892 Implementation Internals:
3893 =========================
3895 The following is not intended to be a complete description of every
3896 implementation detail. However, it should help to understand the
3897 inner workings of U-Boot and make it easier to port it to custom
3901 Initial Stack, Global Data:
3902 ---------------------------
3904 The implementation of U-Boot is complicated by the fact that U-Boot
3905 starts running out of ROM (flash memory), usually without access to
3906 system RAM (because the memory controller is not initialized yet).
3907 This means that we don't have writable Data or BSS segments, and BSS
3908 is not initialized as zero. To be able to get a C environment working
3909 at all, we have to allocate at least a minimal stack. Implementation
3910 options for this are defined and restricted by the CPU used: Some CPU
3911 models provide on-chip memory (like the IMMR area on MPC8xx and
3912 MPC826x processors), on others (parts of) the data cache can be
3913 locked as (mis-) used as memory, etc.
3915 Chris Hallinan posted a good summary of these issues to the
3916 U-Boot mailing list:
3918 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3919 From: "Chris Hallinan" <clh@net1plus.com>
3920 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3923 Correct me if I'm wrong, folks, but the way I understand it
3924 is this: Using DCACHE as initial RAM for Stack, etc, does not
3925 require any physical RAM backing up the cache. The cleverness
3926 is that the cache is being used as a temporary supply of
3927 necessary storage before the SDRAM controller is setup. It's
3928 beyond the scope of this list to explain the details, but you
3929 can see how this works by studying the cache architecture and
3930 operation in the architecture and processor-specific manuals.
3932 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3933 is another option for the system designer to use as an
3934 initial stack/RAM area prior to SDRAM being available. Either
3935 option should work for you. Using CS 4 should be fine if your
3936 board designers haven't used it for something that would
3937 cause you grief during the initial boot! It is frequently not
3940 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
3941 with your processor/board/system design. The default value
3942 you will find in any recent u-boot distribution in
3943 walnut.h should work for you. I'd set it to a value larger
3944 than your SDRAM module. If you have a 64MB SDRAM module, set
3945 it above 400_0000. Just make sure your board has no resources
3946 that are supposed to respond to that address! That code in
3947 start.S has been around a while and should work as is when
3948 you get the config right.
3953 It is essential to remember this, since it has some impact on the C
3954 code for the initialization procedures:
3956 * Initialized global data (data segment) is read-only. Do not attempt
3959 * Do not use any uninitialized global data (or implicitely initialized
3960 as zero data - BSS segment) at all - this is undefined, initiali-
3961 zation is performed later (when relocating to RAM).
3963 * Stack space is very limited. Avoid big data buffers or things like
3966 Having only the stack as writable memory limits means we cannot use
3967 normal global data to share information beween the code. But it
3968 turned out that the implementation of U-Boot can be greatly
3969 simplified by making a global data structure (gd_t) available to all
3970 functions. We could pass a pointer to this data as argument to _all_
3971 functions, but this would bloat the code. Instead we use a feature of
3972 the GCC compiler (Global Register Variables) to share the data: we
3973 place a pointer (gd) to the global data into a register which we
3974 reserve for this purpose.
3976 When choosing a register for such a purpose we are restricted by the
3977 relevant (E)ABI specifications for the current architecture, and by
3978 GCC's implementation.
3980 For PowerPC, the following registers have specific use:
3982 R2: reserved for system use
3983 R3-R4: parameter passing and return values
3984 R5-R10: parameter passing
3985 R13: small data area pointer
3989 (U-Boot also uses R12 as internal GOT pointer. r12
3990 is a volatile register so r12 needs to be reset when
3991 going back and forth between asm and C)
3993 ==> U-Boot will use R2 to hold a pointer to the global data
3995 Note: on PPC, we could use a static initializer (since the
3996 address of the global data structure is known at compile time),
3997 but it turned out that reserving a register results in somewhat
3998 smaller code - although the code savings are not that big (on
3999 average for all boards 752 bytes for the whole U-Boot image,
4000 624 text + 127 data).
4002 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4003 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4005 ==> U-Boot will use P3 to hold a pointer to the global data
4007 On ARM, the following registers are used:
4009 R0: function argument word/integer result
4010 R1-R3: function argument word
4012 R10: stack limit (used only if stack checking if enabled)
4013 R11: argument (frame) pointer
4014 R12: temporary workspace
4017 R15: program counter
4019 ==> U-Boot will use R8 to hold a pointer to the global data
4021 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4022 or current versions of GCC may "optimize" the code too much.
4027 U-Boot runs in system state and uses physical addresses, i.e. the
4028 MMU is not used either for address mapping nor for memory protection.
4030 The available memory is mapped to fixed addresses using the memory
4031 controller. In this process, a contiguous block is formed for each
4032 memory type (Flash, SDRAM, SRAM), even when it consists of several
4033 physical memory banks.
4035 U-Boot is installed in the first 128 kB of the first Flash bank (on
4036 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4037 booting and sizing and initializing DRAM, the code relocates itself
4038 to the upper end of DRAM. Immediately below the U-Boot code some
4039 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4040 configuration setting]. Below that, a structure with global Board
4041 Info data is placed, followed by the stack (growing downward).
4043 Additionally, some exception handler code is copied to the low 8 kB
4044 of DRAM (0x00000000 ... 0x00001FFF).
4046 So a typical memory configuration with 16 MB of DRAM could look like
4049 0x0000 0000 Exception Vector code
4052 0x0000 2000 Free for Application Use
4058 0x00FB FF20 Monitor Stack (Growing downward)
4059 0x00FB FFAC Board Info Data and permanent copy of global data
4060 0x00FC 0000 Malloc Arena
4063 0x00FE 0000 RAM Copy of Monitor Code
4064 ... eventually: LCD or video framebuffer
4065 ... eventually: pRAM (Protected RAM - unchanged by reset)
4066 0x00FF FFFF [End of RAM]
4069 System Initialization:
4070 ----------------------
4072 In the reset configuration, U-Boot starts at the reset entry point
4073 (on most PowerPC systems at address 0x00000100). Because of the reset
4074 configuration for CS0# this is a mirror of the onboard Flash memory.
4075 To be able to re-map memory U-Boot then jumps to its link address.
4076 To be able to implement the initialization code in C, a (small!)
4077 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4078 which provide such a feature like MPC8xx or MPC8260), or in a locked
4079 part of the data cache. After that, U-Boot initializes the CPU core,
4080 the caches and the SIU.
4082 Next, all (potentially) available memory banks are mapped using a
4083 preliminary mapping. For example, we put them on 512 MB boundaries
4084 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4085 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4086 programmed for SDRAM access. Using the temporary configuration, a
4087 simple memory test is run that determines the size of the SDRAM
4090 When there is more than one SDRAM bank, and the banks are of
4091 different size, the largest is mapped first. For equal size, the first
4092 bank (CS2#) is mapped first. The first mapping is always for address
4093 0x00000000, with any additional banks following immediately to create
4094 contiguous memory starting from 0.
4096 Then, the monitor installs itself at the upper end of the SDRAM area
4097 and allocates memory for use by malloc() and for the global Board
4098 Info data; also, the exception vector code is copied to the low RAM
4099 pages, and the final stack is set up.
4101 Only after this relocation will you have a "normal" C environment;
4102 until that you are restricted in several ways, mostly because you are
4103 running from ROM, and because the code will have to be relocated to a
4107 U-Boot Porting Guide:
4108 ----------------------
4110 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4114 int main(int argc, char *argv[])
4116 sighandler_t no_more_time;
4118 signal(SIGALRM, no_more_time);
4119 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4121 if (available_money > available_manpower) {
4122 Pay consultant to port U-Boot;
4126 Download latest U-Boot source;
4128 Subscribe to u-boot mailing list;
4131 email("Hi, I am new to U-Boot, how do I get started?");
4134 Read the README file in the top level directory;
4135 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4136 Read applicable doc/*.README;
4137 Read the source, Luke;
4138 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4141 if (available_money > toLocalCurrency ($2500))
4144 Add a lot of aggravation and time;
4146 if (a similar board exists) { /* hopefully... */
4147 cp -a board/<similar> board/<myboard>
4148 cp include/configs/<similar>.h include/configs/<myboard>.h
4150 Create your own board support subdirectory;
4151 Create your own board include/configs/<myboard>.h file;
4153 Edit new board/<myboard> files
4154 Edit new include/configs/<myboard>.h
4159 Add / modify source code;
4163 email("Hi, I am having problems...");
4165 Send patch file to the U-Boot email list;
4166 if (reasonable critiques)
4167 Incorporate improvements from email list code review;
4169 Defend code as written;
4175 void no_more_time (int sig)
4184 All contributions to U-Boot should conform to the Linux kernel
4185 coding style; see the file "Documentation/CodingStyle" and the script
4186 "scripts/Lindent" in your Linux kernel source directory. In sources
4187 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
4188 spaces before parameters to function calls) is actually used.
4190 Source files originating from a different project (for example the
4191 MTD subsystem) are generally exempt from these guidelines and are not
4192 reformated to ease subsequent migration to newer versions of those
4195 Please note that U-Boot is implemented in C (and to some small parts in
4196 Assembler); no C++ is used, so please do not use C++ style comments (//)
4199 Please also stick to the following formatting rules:
4200 - remove any trailing white space
4201 - use TAB characters for indentation, not spaces
4202 - make sure NOT to use DOS '\r\n' line feeds
4203 - do not add more than 2 empty lines to source files
4204 - do not add trailing empty lines to source files
4206 Submissions which do not conform to the standards may be returned
4207 with a request to reformat the changes.
4213 Since the number of patches for U-Boot is growing, we need to
4214 establish some rules. Submissions which do not conform to these rules
4215 may be rejected, even when they contain important and valuable stuff.
4217 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4219 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4220 see http://lists.denx.de/mailman/listinfo/u-boot
4222 When you send a patch, please include the following information with
4225 * For bug fixes: a description of the bug and how your patch fixes
4226 this bug. Please try to include a way of demonstrating that the
4227 patch actually fixes something.
4229 * For new features: a description of the feature and your
4232 * A CHANGELOG entry as plaintext (separate from the patch)
4234 * For major contributions, your entry to the CREDITS file
4236 * When you add support for a new board, don't forget to add this
4237 board to the MAKEALL script, too.
4239 * If your patch adds new configuration options, don't forget to
4240 document these in the README file.
4242 * The patch itself. If you are using git (which is *strongly*
4243 recommended) you can easily generate the patch using the
4244 "git-format-patch". If you then use "git-send-email" to send it to
4245 the U-Boot mailing list, you will avoid most of the common problems
4246 with some other mail clients.
4248 If you cannot use git, use "diff -purN OLD NEW". If your version of
4249 diff does not support these options, then get the latest version of
4252 The current directory when running this command shall be the parent
4253 directory of the U-Boot source tree (i. e. please make sure that
4254 your patch includes sufficient directory information for the
4257 We prefer patches as plain text. MIME attachments are discouraged,
4258 and compressed attachments must not be used.
4260 * If one logical set of modifications affects or creates several
4261 files, all these changes shall be submitted in a SINGLE patch file.
4263 * Changesets that contain different, unrelated modifications shall be
4264 submitted as SEPARATE patches, one patch per changeset.
4269 * Before sending the patch, run the MAKEALL script on your patched
4270 source tree and make sure that no errors or warnings are reported
4271 for any of the boards.
4273 * Keep your modifications to the necessary minimum: A patch
4274 containing several unrelated changes or arbitrary reformats will be
4275 returned with a request to re-formatting / split it.
4277 * If you modify existing code, make sure that your new code does not
4278 add to the memory footprint of the code ;-) Small is beautiful!
4279 When adding new features, these should compile conditionally only
4280 (using #ifdef), and the resulting code with the new feature
4281 disabled must not need more memory than the old code without your
4284 * Remember that there is a size limit of 100 kB per message on the
4285 u-boot mailing list. Bigger patches will be moderated. If they are
4286 reasonable and not too big, they will be acknowledged. But patches
4287 bigger than the size limit should be avoided.
projects / karo-tx-uboot.git / blob