2 # (C) Copyright 2000 - 2012
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 Starting with the release in October 2008, the names of the releases
130 were changed from numerical release numbers without deeper meaning
131 into a time stamp based numbering. Regular releases are identified by
132 names consisting of the calendar year and month of the release date.
133 Additional fields (if present) indicate release candidates or bug fix
134 releases in "stable" maintenance trees.
137 U-Boot v2009.11 - Release November 2009
138 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
139 U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
145 /arch Architecture specific files
146 /arm Files generic to ARM architecture
147 /cpu CPU specific files
148 /arm720t Files specific to ARM 720 CPUs
149 /arm920t Files specific to ARM 920 CPUs
150 /at91 Files specific to Atmel AT91RM9200 CPU
151 /imx Files specific to Freescale MC9328 i.MX CPUs
152 /s3c24x0 Files specific to Samsung S3C24X0 CPUs
153 /arm925t Files specific to ARM 925 CPUs
154 /arm926ejs Files specific to ARM 926 CPUs
155 /arm1136 Files specific to ARM 1136 CPUs
156 /ixp Files specific to Intel XScale IXP CPUs
157 /pxa Files specific to Intel XScale PXA CPUs
158 /s3c44b0 Files specific to Samsung S3C44B0 CPUs
159 /sa1100 Files specific to Intel StrongARM SA1100 CPUs
160 /lib Architecture specific library files
161 /avr32 Files generic to AVR32 architecture
162 /cpu CPU specific files
163 /lib Architecture specific library files
164 /blackfin Files generic to Analog Devices Blackfin architecture
165 /cpu CPU specific files
166 /lib Architecture specific library files
167 /x86 Files generic to x86 architecture
168 /cpu CPU specific files
169 /lib Architecture specific library files
170 /m68k Files generic to m68k architecture
171 /cpu CPU specific files
172 /mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
173 /mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
174 /mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
175 /mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
176 /mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
177 /lib Architecture specific library files
178 /microblaze Files generic to microblaze architecture
179 /cpu CPU specific files
180 /lib Architecture specific library files
181 /mips Files generic to MIPS architecture
182 /cpu CPU specific files
183 /mips32 Files specific to MIPS32 CPUs
184 /xburst Files specific to Ingenic XBurst CPUs
185 /lib Architecture specific library files
186 /nds32 Files generic to NDS32 architecture
187 /cpu CPU specific files
188 /n1213 Files specific to Andes Technology N1213 CPUs
189 /lib Architecture specific library files
190 /nios2 Files generic to Altera NIOS2 architecture
191 /cpu CPU specific files
192 /lib Architecture specific library files
193 /powerpc Files generic to PowerPC architecture
194 /cpu CPU specific files
195 /74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
196 /mpc5xx Files specific to Freescale MPC5xx CPUs
197 /mpc5xxx Files specific to Freescale MPC5xxx CPUs
198 /mpc8xx Files specific to Freescale MPC8xx CPUs
199 /mpc8220 Files specific to Freescale MPC8220 CPUs
200 /mpc824x Files specific to Freescale MPC824x CPUs
201 /mpc8260 Files specific to Freescale MPC8260 CPUs
202 /mpc85xx Files specific to Freescale MPC85xx CPUs
203 /ppc4xx Files specific to AMCC PowerPC 4xx CPUs
204 /lib Architecture specific library files
205 /sh Files generic to SH architecture
206 /cpu CPU specific files
207 /sh2 Files specific to sh2 CPUs
208 /sh3 Files specific to sh3 CPUs
209 /sh4 Files specific to sh4 CPUs
210 /lib Architecture specific library files
211 /sparc Files generic to SPARC architecture
212 /cpu CPU specific files
213 /leon2 Files specific to Gaisler LEON2 SPARC CPU
214 /leon3 Files specific to Gaisler LEON3 SPARC CPU
215 /lib Architecture specific library files
216 /api Machine/arch independent API for external apps
217 /board Board dependent files
218 /common Misc architecture independent functions
219 /disk Code for disk drive partition handling
220 /doc Documentation (don't expect too much)
221 /drivers Commonly used device drivers
222 /examples Example code for standalone applications, etc.
223 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
224 /include Header Files
225 /lib Files generic to all architectures
226 /libfdt Library files to support flattened device trees
227 /lzma Library files to support LZMA decompression
228 /lzo Library files to support LZO decompression
230 /post Power On Self Test
231 /rtc Real Time Clock drivers
232 /tools Tools to build S-Record or U-Boot images, etc.
234 Software Configuration:
235 =======================
237 Configuration is usually done using C preprocessor defines; the
238 rationale behind that is to avoid dead code whenever possible.
240 There are two classes of configuration variables:
242 * Configuration _OPTIONS_:
243 These are selectable by the user and have names beginning with
246 * Configuration _SETTINGS_:
247 These depend on the hardware etc. and should not be meddled with if
248 you don't know what you're doing; they have names beginning with
251 Later we will add a configuration tool - probably similar to or even
252 identical to what's used for the Linux kernel. Right now, we have to
253 do the configuration by hand, which means creating some symbolic
254 links and editing some configuration files. We use the TQM8xxL boards
258 Selection of Processor Architecture and Board Type:
259 ---------------------------------------------------
261 For all supported boards there are ready-to-use default
262 configurations available; just type "make <board_name>_config".
264 Example: For a TQM823L module type:
269 For the Cogent platform, you need to specify the CPU type as well;
270 e.g. "make cogent_mpc8xx_config". And also configure the cogent
271 directory according to the instructions in cogent/README.
274 Configuration Options:
275 ----------------------
277 Configuration depends on the combination of board and CPU type; all
278 such information is kept in a configuration file
279 "include/configs/<board_name>.h".
281 Example: For a TQM823L module, all configuration settings are in
282 "include/configs/TQM823L.h".
285 Many of the options are named exactly as the corresponding Linux
286 kernel configuration options. The intention is to make it easier to
287 build a config tool - later.
290 The following options need to be configured:
292 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
294 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
296 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
297 Define exactly one, e.g. CONFIG_ATSTK1002
299 - CPU Module Type: (if CONFIG_COGENT is defined)
300 Define exactly one of
302 --- FIXME --- not tested yet:
303 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
304 CONFIG_CMA287_23, CONFIG_CMA287_50
306 - Motherboard Type: (if CONFIG_COGENT is defined)
307 Define exactly one of
308 CONFIG_CMA101, CONFIG_CMA102
310 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
311 Define one or more of
314 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
315 Define one or more of
316 CONFIG_LCD_HEARTBEAT - update a character position on
317 the LCD display every second with
320 - Board flavour: (if CONFIG_MPC8260ADS is defined)
323 CONFIG_SYS_8260ADS - original MPC8260ADS
324 CONFIG_SYS_8266ADS - MPC8266ADS
325 CONFIG_SYS_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
326 CONFIG_SYS_8272ADS - MPC8272ADS
328 - Marvell Family Member
329 CONFIG_SYS_MVFS - define it if you want to enable
330 multiple fs option at one time
331 for marvell soc family
333 - MPC824X Family Member (if CONFIG_MPC824X is defined)
334 Define exactly one of
335 CONFIG_MPC8240, CONFIG_MPC8245
337 - 8xx CPU Options: (if using an MPC8xx CPU)
338 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
339 get_gclk_freq() cannot work
340 e.g. if there is no 32KHz
341 reference PIT/RTC clock
342 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
345 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
346 CONFIG_SYS_8xx_CPUCLK_MIN
347 CONFIG_SYS_8xx_CPUCLK_MAX
348 CONFIG_8xx_CPUCLK_DEFAULT
349 See doc/README.MPC866
351 CONFIG_SYS_MEASURE_CPUCLK
353 Define this to measure the actual CPU clock instead
354 of relying on the correctness of the configured
355 values. Mostly useful for board bringup to make sure
356 the PLL is locked at the intended frequency. Note
357 that this requires a (stable) reference clock (32 kHz
358 RTC clock or CONFIG_SYS_8XX_XIN)
360 CONFIG_SYS_DELAYED_ICACHE
362 Define this option if you want to enable the
363 ICache only when Code runs from RAM.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 - Generic CPU options:
378 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
380 Defines the endianess of the CPU. Implementation of those
381 values is arch specific.
383 - Intel Monahans options:
384 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
386 Defines the Monahans run mode to oscillator
387 ratio. Valid values are 8, 16, 24, 31. The core
388 frequency is this value multiplied by 13 MHz.
390 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
392 Defines the Monahans turbo mode to oscillator
393 ratio. Valid values are 1 (default if undefined) and
394 2. The core frequency as calculated above is multiplied
398 CONFIG_SYS_INIT_SP_OFFSET
400 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
401 pointer. This is needed for the temporary stack before
404 CONFIG_SYS_MIPS_CACHE_MODE
406 Cache operation mode for the MIPS CPU.
407 See also arch/mips/include/asm/mipsregs.h.
409 CONF_CM_CACHABLE_NO_WA
412 CONF_CM_CACHABLE_NONCOHERENT
416 CONF_CM_CACHABLE_ACCELERATED
418 CONFIG_SYS_XWAY_EBU_BOOTCFG
420 Special option for Lantiq XWAY SoCs for booting from NOR flash.
421 See also arch/mips/cpu/mips32/start.S.
423 CONFIG_XWAY_SWAP_BYTES
425 Enable compilation of tools/xway-swap-bytes needed for Lantiq
426 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
427 be swapped if a flash programmer is used.
430 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
432 Select high exception vectors of the ARM core, e.g., do not
433 clear the V bit of the c1 register of CP15.
435 CONFIG_SYS_THUMB_BUILD
437 Use this flag to build U-Boot using the Thumb instruction
438 set for ARM architectures. Thumb instruction set provides
439 better code density. For ARM architectures that support
440 Thumb2 this flag will result in Thumb2 code generated by
443 - Linux Kernel Interface:
446 U-Boot stores all clock information in Hz
447 internally. For binary compatibility with older Linux
448 kernels (which expect the clocks passed in the
449 bd_info data to be in MHz) the environment variable
450 "clocks_in_mhz" can be defined so that U-Boot
451 converts clock data to MHZ before passing it to the
453 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
454 "clocks_in_mhz=1" is automatically included in the
457 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
459 When transferring memsize parameter to linux, some versions
460 expect it to be in bytes, others in MB.
461 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
465 New kernel versions are expecting firmware settings to be
466 passed using flattened device trees (based on open firmware
470 * New libfdt-based support
471 * Adds the "fdt" command
472 * The bootm command automatically updates the fdt
474 OF_CPU - The proper name of the cpus node (only required for
475 MPC512X and MPC5xxx based boards).
476 OF_SOC - The proper name of the soc node (only required for
477 MPC512X and MPC5xxx based boards).
478 OF_TBCLK - The timebase frequency.
479 OF_STDOUT_PATH - The path to the console device
481 boards with QUICC Engines require OF_QE to set UCC MAC
484 CONFIG_OF_BOARD_SETUP
486 Board code has addition modification that it wants to make
487 to the flat device tree before handing it off to the kernel
491 This define fills in the correct boot CPU in the boot
492 param header, the default value is zero if undefined.
496 U-Boot can detect if an IDE device is present or not.
497 If not, and this new config option is activated, U-Boot
498 removes the ATA node from the DTS before booting Linux,
499 so the Linux IDE driver does not probe the device and
500 crash. This is needed for buggy hardware (uc101) where
501 no pull down resistor is connected to the signal IDE5V_DD7.
503 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
505 This setting is mandatory for all boards that have only one
506 machine type and must be used to specify the machine type
507 number as it appears in the ARM machine registry
508 (see http://www.arm.linux.org.uk/developer/machines/).
509 Only boards that have multiple machine types supported
510 in a single configuration file and the machine type is
511 runtime discoverable, do not have to use this setting.
513 - vxWorks boot parameters:
515 bootvx constructs a valid bootline using the following
516 environments variables: bootfile, ipaddr, serverip, hostname.
517 It loads the vxWorks image pointed bootfile.
519 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
520 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
521 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
522 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
524 CONFIG_SYS_VXWORKS_ADD_PARAMS
526 Add it at the end of the bootline. E.g "u=username pw=secret"
528 Note: If a "bootargs" environment is defined, it will overwride
529 the defaults discussed just above.
531 - Cache Configuration:
532 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
533 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
534 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
536 - Cache Configuration for ARM:
537 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
539 CONFIG_SYS_PL310_BASE - Physical base address of PL310
540 controller register space
545 Define this if you want support for Amba PrimeCell PL010 UARTs.
549 Define this if you want support for Amba PrimeCell PL011 UARTs.
553 If you have Amba PrimeCell PL011 UARTs, set this variable to
554 the clock speed of the UARTs.
558 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
559 define this to a list of base addresses for each (supported)
560 port. See e.g. include/configs/versatile.h
562 CONFIG_PL011_SERIAL_RLCR
564 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
565 have separate receive and transmit line control registers. Set
566 this variable to initialize the extra register.
568 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
570 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
571 boot loader that has already initialized the UART. Define this
572 variable to flush the UART at init time.
576 Depending on board, define exactly one serial port
577 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
578 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
579 console by defining CONFIG_8xx_CONS_NONE
581 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
582 port routines must be defined elsewhere
583 (i.e. serial_init(), serial_getc(), ...)
586 Enables console device for a color framebuffer. Needs following
587 defines (cf. smiLynxEM, i8042)
588 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
590 VIDEO_HW_RECTFILL graphic chip supports
593 VIDEO_HW_BITBLT graphic chip supports
594 bit-blit (cf. smiLynxEM)
595 VIDEO_VISIBLE_COLS visible pixel columns
597 VIDEO_VISIBLE_ROWS visible pixel rows
598 VIDEO_PIXEL_SIZE bytes per pixel
599 VIDEO_DATA_FORMAT graphic data format
600 (0-5, cf. cfb_console.c)
601 VIDEO_FB_ADRS framebuffer address
602 VIDEO_KBD_INIT_FCT keyboard int fct
603 (i.e. i8042_kbd_init())
604 VIDEO_TSTC_FCT test char fct
606 VIDEO_GETC_FCT get char fct
608 CONFIG_CONSOLE_CURSOR cursor drawing on/off
609 (requires blink timer
611 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
612 CONFIG_CONSOLE_TIME display time/date info in
614 (requires CONFIG_CMD_DATE)
615 CONFIG_VIDEO_LOGO display Linux logo in
617 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
618 linux_logo.h for logo.
619 Requires CONFIG_VIDEO_LOGO
620 CONFIG_CONSOLE_EXTRA_INFO
621 additional board info beside
624 When CONFIG_CFB_CONSOLE is defined, video console is
625 default i/o. Serial console can be forced with
626 environment 'console=serial'.
628 When CONFIG_SILENT_CONSOLE is defined, all console
629 messages (by U-Boot and Linux!) can be silenced with
630 the "silent" environment variable. See
631 doc/README.silent for more information.
634 CONFIG_BAUDRATE - in bps
635 Select one of the baudrates listed in
636 CONFIG_SYS_BAUDRATE_TABLE, see below.
637 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
639 - Console Rx buffer length
640 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
641 the maximum receive buffer length for the SMC.
642 This option is actual only for 82xx and 8xx possible.
643 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
644 must be defined, to setup the maximum idle timeout for
647 - Pre-Console Buffer:
648 Prior to the console being initialised (i.e. serial UART
649 initialised etc) all console output is silently discarded.
650 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
651 buffer any console messages prior to the console being
652 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
653 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
654 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
655 bytes are output before the console is initialised, the
656 earlier bytes are discarded.
658 'Sane' compilers will generate smaller code if
659 CONFIG_PRE_CON_BUF_SZ is a power of 2
661 - Safe printf() functions
662 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
663 the printf() functions. These are defined in
664 include/vsprintf.h and include snprintf(), vsnprintf() and
665 so on. Code size increase is approximately 300-500 bytes.
666 If this option is not given then these functions will
667 silently discard their buffer size argument - this means
668 you are not getting any overflow checking in this case.
670 - Boot Delay: CONFIG_BOOTDELAY - in seconds
671 Delay before automatically booting the default image;
672 set to -1 to disable autoboot.
674 See doc/README.autoboot for these options that
675 work with CONFIG_BOOTDELAY. None are required.
676 CONFIG_BOOT_RETRY_TIME
677 CONFIG_BOOT_RETRY_MIN
678 CONFIG_AUTOBOOT_KEYED
679 CONFIG_AUTOBOOT_PROMPT
680 CONFIG_AUTOBOOT_DELAY_STR
681 CONFIG_AUTOBOOT_STOP_STR
682 CONFIG_AUTOBOOT_DELAY_STR2
683 CONFIG_AUTOBOOT_STOP_STR2
684 CONFIG_ZERO_BOOTDELAY_CHECK
685 CONFIG_RESET_TO_RETRY
689 Only needed when CONFIG_BOOTDELAY is enabled;
690 define a command string that is automatically executed
691 when no character is read on the console interface
692 within "Boot Delay" after reset.
695 This can be used to pass arguments to the bootm
696 command. The value of CONFIG_BOOTARGS goes into the
697 environment value "bootargs".
699 CONFIG_RAMBOOT and CONFIG_NFSBOOT
700 The value of these goes into the environment as
701 "ramboot" and "nfsboot" respectively, and can be used
702 as a convenience, when switching between booting from
708 When this option is #defined, the existence of the
709 environment variable "preboot" will be checked
710 immediately before starting the CONFIG_BOOTDELAY
711 countdown and/or running the auto-boot command resp.
712 entering interactive mode.
714 This feature is especially useful when "preboot" is
715 automatically generated or modified. For an example
716 see the LWMON board specific code: here "preboot" is
717 modified when the user holds down a certain
718 combination of keys on the (special) keyboard when
721 - Serial Download Echo Mode:
723 If defined to 1, all characters received during a
724 serial download (using the "loads" command) are
725 echoed back. This might be needed by some terminal
726 emulations (like "cu"), but may as well just take
727 time on others. This setting #define's the initial
728 value of the "loads_echo" environment variable.
730 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
732 Select one of the baudrates listed in
733 CONFIG_SYS_BAUDRATE_TABLE, see below.
736 Monitor commands can be included or excluded
737 from the build by using the #include files
738 "config_cmd_all.h" and #undef'ing unwanted
739 commands, or using "config_cmd_default.h"
740 and augmenting with additional #define's
743 The default command configuration includes all commands
744 except those marked below with a "*".
746 CONFIG_CMD_ASKENV * ask for env variable
747 CONFIG_CMD_BDI bdinfo
748 CONFIG_CMD_BEDBUG * Include BedBug Debugger
749 CONFIG_CMD_BMP * BMP support
750 CONFIG_CMD_BSP * Board specific commands
751 CONFIG_CMD_BOOTD bootd
752 CONFIG_CMD_CACHE * icache, dcache
753 CONFIG_CMD_CONSOLE coninfo
754 CONFIG_CMD_CRC32 * crc32
755 CONFIG_CMD_DATE * support for RTC, date/time...
756 CONFIG_CMD_DHCP * DHCP support
757 CONFIG_CMD_DIAG * Diagnostics
758 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
759 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
760 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
761 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
762 CONFIG_CMD_DTT * Digital Therm and Thermostat
763 CONFIG_CMD_ECHO echo arguments
764 CONFIG_CMD_EDITENV edit env variable
765 CONFIG_CMD_EEPROM * EEPROM read/write support
766 CONFIG_CMD_ELF * bootelf, bootvx
767 CONFIG_CMD_EXPORTENV * export the environment
768 CONFIG_CMD_SAVEENV saveenv
769 CONFIG_CMD_FDC * Floppy Disk Support
770 CONFIG_CMD_FAT * FAT partition support
771 CONFIG_CMD_FDOS * Dos diskette Support
772 CONFIG_CMD_FLASH flinfo, erase, protect
773 CONFIG_CMD_FPGA FPGA device initialization support
774 CONFIG_CMD_GO * the 'go' command (exec code)
775 CONFIG_CMD_GREPENV * search environment
776 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
777 CONFIG_CMD_I2C * I2C serial bus support
778 CONFIG_CMD_IDE * IDE harddisk support
779 CONFIG_CMD_IMI iminfo
780 CONFIG_CMD_IMLS List all found images
781 CONFIG_CMD_IMMAP * IMMR dump support
782 CONFIG_CMD_IMPORTENV * import an environment
783 CONFIG_CMD_IRQ * irqinfo
784 CONFIG_CMD_ITEST Integer/string test of 2 values
785 CONFIG_CMD_JFFS2 * JFFS2 Support
786 CONFIG_CMD_KGDB * kgdb
787 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
788 CONFIG_CMD_LOADB loadb
789 CONFIG_CMD_LOADS loads
790 CONFIG_CMD_MD5SUM print md5 message digest
791 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
792 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
794 CONFIG_CMD_MISC Misc functions like sleep etc
795 CONFIG_CMD_MMC * MMC memory mapped support
796 CONFIG_CMD_MII * MII utility commands
797 CONFIG_CMD_MTDPARTS * MTD partition support
798 CONFIG_CMD_NAND * NAND support
799 CONFIG_CMD_NET bootp, tftpboot, rarpboot
800 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
801 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
802 CONFIG_CMD_PCI * pciinfo
803 CONFIG_CMD_PCMCIA * PCMCIA support
804 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
806 CONFIG_CMD_PORTIO * Port I/O
807 CONFIG_CMD_REGINFO * Register dump
808 CONFIG_CMD_RUN run command in env variable
809 CONFIG_CMD_SAVES * save S record dump
810 CONFIG_CMD_SCSI * SCSI Support
811 CONFIG_CMD_SDRAM * print SDRAM configuration information
812 (requires CONFIG_CMD_I2C)
813 CONFIG_CMD_SETGETDCR Support for DCR Register access
815 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
816 CONFIG_CMD_SHA1SUM print sha1 memory digest
817 (requires CONFIG_CMD_MEMORY)
818 CONFIG_CMD_SOURCE "source" command Support
819 CONFIG_CMD_SPI * SPI serial bus support
820 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
821 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
822 CONFIG_CMD_TIME * run command and report execution time
823 CONFIG_CMD_USB * USB support
824 CONFIG_CMD_CDP * Cisco Discover Protocol support
825 CONFIG_CMD_MFSL * Microblaze FSL support
828 EXAMPLE: If you want all functions except of network
829 support you can write:
831 #include "config_cmd_all.h"
832 #undef CONFIG_CMD_NET
835 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
837 Note: Don't enable the "icache" and "dcache" commands
838 (configuration option CONFIG_CMD_CACHE) unless you know
839 what you (and your U-Boot users) are doing. Data
840 cache cannot be enabled on systems like the 8xx or
841 8260 (where accesses to the IMMR region must be
842 uncached), and it cannot be disabled on all other
843 systems where we (mis-) use the data cache to hold an
844 initial stack and some data.
847 XXX - this list needs to get updated!
851 If this variable is defined, U-Boot will use a device tree
852 to configure its devices, instead of relying on statically
853 compiled #defines in the board file. This option is
854 experimental and only available on a few boards. The device
855 tree is available in the global data as gd->fdt_blob.
857 U-Boot needs to get its device tree from somewhere. This can
858 be done using one of the two options below:
861 If this variable is defined, U-Boot will embed a device tree
862 binary in its image. This device tree file should be in the
863 board directory and called <soc>-<board>.dts. The binary file
864 is then picked up in board_init_f() and made available through
865 the global data structure as gd->blob.
868 If this variable is defined, U-Boot will build a device tree
869 binary. It will be called u-boot.dtb. Architecture-specific
870 code will locate it at run-time. Generally this works by:
872 cat u-boot.bin u-boot.dtb >image.bin
874 and in fact, U-Boot does this for you, creating a file called
875 u-boot-dtb.bin which is useful in the common case. You can
876 still use the individual files if you need something more
881 If this variable is defined, it enables watchdog
882 support for the SoC. There must be support in the SoC
883 specific code for a watchdog. For the 8xx and 8260
884 CPUs, the SIU Watchdog feature is enabled in the SYPCR
885 register. When supported for a specific SoC is
886 available, then no further board specific code should
890 When using a watchdog circuitry external to the used
891 SoC, then define this variable and provide board
892 specific code for the "hw_watchdog_reset" function.
895 CONFIG_VERSION_VARIABLE
896 If this variable is defined, an environment variable
897 named "ver" is created by U-Boot showing the U-Boot
898 version as printed by the "version" command.
899 This variable is readonly.
903 When CONFIG_CMD_DATE is selected, the type of the RTC
904 has to be selected, too. Define exactly one of the
907 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
908 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
909 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
910 CONFIG_RTC_MC146818 - use MC146818 RTC
911 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
912 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
913 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
914 CONFIG_RTC_DS164x - use Dallas DS164x RTC
915 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
916 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
917 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
918 CONFIG_SYS_RV3029_TCR - enable trickle charger on
921 Note that if the RTC uses I2C, then the I2C interface
922 must also be configured. See I2C Support, below.
925 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
926 CONFIG_PCA953X_INFO - enable pca953x info command
928 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
929 chip-ngpio pairs that tell the PCA953X driver the number of
930 pins supported by a particular chip.
932 Note that if the GPIO device uses I2C, then the I2C interface
933 must also be configured. See I2C Support, below.
937 When CONFIG_TIMESTAMP is selected, the timestamp
938 (date and time) of an image is printed by image
939 commands like bootm or iminfo. This option is
940 automatically enabled when you select CONFIG_CMD_DATE .
943 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
944 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
946 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
947 CONFIG_CMD_SCSI) you must configure support for at
948 least one partition type as well.
951 CONFIG_IDE_RESET_ROUTINE - this is defined in several
952 board configurations files but used nowhere!
954 CONFIG_IDE_RESET - is this is defined, IDE Reset will
955 be performed by calling the function
956 ide_set_reset(int reset)
957 which has to be defined in a board specific file
962 Set this to enable ATAPI support.
967 Set this to enable support for disks larger than 137GB
968 Also look at CONFIG_SYS_64BIT_LBA.
969 Whithout these , LBA48 support uses 32bit variables and will 'only'
970 support disks up to 2.1TB.
972 CONFIG_SYS_64BIT_LBA:
973 When enabled, makes the IDE subsystem use 64bit sector addresses.
977 At the moment only there is only support for the
978 SYM53C8XX SCSI controller; define
979 CONFIG_SCSI_SYM53C8XX to enable it.
981 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
982 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
983 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
984 maximum numbers of LUNs, SCSI ID's and target
986 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
988 - NETWORK Support (PCI):
990 Support for Intel 8254x/8257x gigabit chips.
993 Utility code for direct access to the SPI bus on Intel 8257x.
994 This does not do anything useful unless you set at least one
995 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
997 CONFIG_E1000_SPI_GENERIC
998 Allow generic access to the SPI bus on the Intel 8257x, for
999 example with the "sspi" command.
1002 Management command for E1000 devices. When used on devices
1003 with SPI support you can reprogram the EEPROM from U-Boot.
1005 CONFIG_E1000_FALLBACK_MAC
1006 default MAC for empty EEPROM after production.
1009 Support for Intel 82557/82559/82559ER chips.
1010 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1011 write routine for first time initialisation.
1014 Support for Digital 2114x chips.
1015 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1016 modem chip initialisation (KS8761/QS6611).
1019 Support for National dp83815 chips.
1022 Support for National dp8382[01] gigabit chips.
1024 - NETWORK Support (other):
1026 CONFIG_DRIVER_AT91EMAC
1027 Support for AT91RM9200 EMAC.
1030 Define this to use reduced MII inteface
1032 CONFIG_DRIVER_AT91EMAC_QUIET
1033 If this defined, the driver is quiet.
1034 The driver doen't show link status messages.
1036 CONFIG_CALXEDA_XGMAC
1037 Support for the Calxeda XGMAC device
1039 CONFIG_DRIVER_LAN91C96
1040 Support for SMSC's LAN91C96 chips.
1042 CONFIG_LAN91C96_BASE
1043 Define this to hold the physical address
1044 of the LAN91C96's I/O space
1046 CONFIG_LAN91C96_USE_32_BIT
1047 Define this to enable 32 bit addressing
1049 CONFIG_DRIVER_SMC91111
1050 Support for SMSC's LAN91C111 chip
1052 CONFIG_SMC91111_BASE
1053 Define this to hold the physical address
1054 of the device (I/O space)
1056 CONFIG_SMC_USE_32_BIT
1057 Define this if data bus is 32 bits
1059 CONFIG_SMC_USE_IOFUNCS
1060 Define this to use i/o functions instead of macros
1061 (some hardware wont work with macros)
1063 CONFIG_DRIVER_TI_EMAC
1064 Support for davinci emac
1066 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1067 Define this if you have more then 3 PHYs.
1070 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1072 CONFIG_FTGMAC100_EGIGA
1073 Define this to use GE link update with gigabit PHY.
1074 Define this if FTGMAC100 is connected to gigabit PHY.
1075 If your system has 10/100 PHY only, it might not occur
1076 wrong behavior. Because PHY usually return timeout or
1077 useless data when polling gigabit status and gigabit
1078 control registers. This behavior won't affect the
1079 correctnessof 10/100 link speed update.
1082 Support for SMSC's LAN911x and LAN921x chips
1085 Define this to hold the physical address
1086 of the device (I/O space)
1088 CONFIG_SMC911X_32_BIT
1089 Define this if data bus is 32 bits
1091 CONFIG_SMC911X_16_BIT
1092 Define this if data bus is 16 bits. If your processor
1093 automatically converts one 32 bit word to two 16 bit
1094 words you may also try CONFIG_SMC911X_32_BIT.
1097 Support for Renesas on-chip Ethernet controller
1099 CONFIG_SH_ETHER_USE_PORT
1100 Define the number of ports to be used
1102 CONFIG_SH_ETHER_PHY_ADDR
1103 Define the ETH PHY's address
1105 CONFIG_SH_ETHER_CACHE_WRITEBACK
1106 If this option is set, the driver enables cache flush.
1109 CONFIG_GENERIC_LPC_TPM
1110 Support for generic parallel port TPM devices. Only one device
1111 per system is supported at this time.
1113 CONFIG_TPM_TIS_BASE_ADDRESS
1114 Base address where the generic TPM device is mapped
1115 to. Contemporary x86 systems usually map it at
1119 At the moment only the UHCI host controller is
1120 supported (PIP405, MIP405, MPC5200); define
1121 CONFIG_USB_UHCI to enable it.
1122 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1123 and define CONFIG_USB_STORAGE to enable the USB
1126 Supported are USB Keyboards and USB Floppy drives
1128 MPC5200 USB requires additional defines:
1130 for 528 MHz Clock: 0x0001bbbb
1134 for differential drivers: 0x00001000
1135 for single ended drivers: 0x00005000
1136 for differential drivers on PSC3: 0x00000100
1137 for single ended drivers on PSC3: 0x00004100
1138 CONFIG_SYS_USB_EVENT_POLL
1139 May be defined to allow interrupt polling
1140 instead of using asynchronous interrupts
1142 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1143 txfilltuning field in the EHCI controller on reset.
1146 Define the below if you wish to use the USB console.
1147 Once firmware is rebuilt from a serial console issue the
1148 command "setenv stdin usbtty; setenv stdout usbtty" and
1149 attach your USB cable. The Unix command "dmesg" should print
1150 it has found a new device. The environment variable usbtty
1151 can be set to gserial or cdc_acm to enable your device to
1152 appear to a USB host as a Linux gserial device or a
1153 Common Device Class Abstract Control Model serial device.
1154 If you select usbtty = gserial you should be able to enumerate
1156 # modprobe usbserial vendor=0xVendorID product=0xProductID
1157 else if using cdc_acm, simply setting the environment
1158 variable usbtty to be cdc_acm should suffice. The following
1159 might be defined in YourBoardName.h
1162 Define this to build a UDC device
1165 Define this to have a tty type of device available to
1166 talk to the UDC device
1169 Define this to enable the high speed support for usb
1170 device and usbtty. If this feature is enabled, a routine
1171 int is_usbd_high_speed(void)
1172 also needs to be defined by the driver to dynamically poll
1173 whether the enumeration has succeded at high speed or full
1176 CONFIG_SYS_CONSOLE_IS_IN_ENV
1177 Define this if you want stdin, stdout &/or stderr to
1181 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1182 Derive USB clock from external clock "blah"
1183 - CONFIG_SYS_USB_EXTC_CLK 0x02
1185 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1186 Derive USB clock from brgclk
1187 - CONFIG_SYS_USB_BRG_CLK 0x04
1189 If you have a USB-IF assigned VendorID then you may wish to
1190 define your own vendor specific values either in BoardName.h
1191 or directly in usbd_vendor_info.h. If you don't define
1192 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1193 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1194 should pretend to be a Linux device to it's target host.
1196 CONFIG_USBD_MANUFACTURER
1197 Define this string as the name of your company for
1198 - CONFIG_USBD_MANUFACTURER "my company"
1200 CONFIG_USBD_PRODUCT_NAME
1201 Define this string as the name of your product
1202 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1204 CONFIG_USBD_VENDORID
1205 Define this as your assigned Vendor ID from the USB
1206 Implementors Forum. This *must* be a genuine Vendor ID
1207 to avoid polluting the USB namespace.
1208 - CONFIG_USBD_VENDORID 0xFFFF
1210 CONFIG_USBD_PRODUCTID
1211 Define this as the unique Product ID
1213 - CONFIG_USBD_PRODUCTID 0xFFFF
1215 - ULPI Layer Support:
1216 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1217 the generic ULPI layer. The generic layer accesses the ULPI PHY
1218 via the platform viewport, so you need both the genric layer and
1219 the viewport enabled. Currently only Chipidea/ARC based
1220 viewport is supported.
1221 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1222 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1225 The MMC controller on the Intel PXA is supported. To
1226 enable this define CONFIG_MMC. The MMC can be
1227 accessed from the boot prompt by mapping the device
1228 to physical memory similar to flash. Command line is
1229 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1230 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1233 Support for Renesas on-chip MMCIF controller
1235 CONFIG_SH_MMCIF_ADDR
1236 Define the base address of MMCIF registers
1239 Define the clock frequency for MMCIF
1241 - Journaling Flash filesystem support:
1242 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1243 CONFIG_JFFS2_NAND_DEV
1244 Define these for a default partition on a NAND device
1246 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1247 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1248 Define these for a default partition on a NOR device
1250 CONFIG_SYS_JFFS_CUSTOM_PART
1251 Define this to create an own partition. You have to provide a
1252 function struct part_info* jffs2_part_info(int part_num)
1254 If you define only one JFFS2 partition you may also want to
1255 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1256 to disable the command chpart. This is the default when you
1257 have not defined a custom partition
1259 - FAT(File Allocation Table) filesystem write function support:
1262 Define this to enable support for saving memory data as a
1263 file in FAT formatted partition.
1265 This will also enable the command "fatwrite" enabling the
1266 user to write files to FAT.
1271 Define this to enable standard (PC-Style) keyboard
1275 Standard PC keyboard driver with US (is default) and
1276 GERMAN key layout (switch via environment 'keymap=de') support.
1277 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1278 for cfb_console. Supports cursor blinking.
1283 Define this to enable video support (for output to
1286 CONFIG_VIDEO_CT69000
1288 Enable Chips & Technologies 69000 Video chip
1290 CONFIG_VIDEO_SMI_LYNXEM
1291 Enable Silicon Motion SMI 712/710/810 Video chip. The
1292 video output is selected via environment 'videoout'
1293 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1296 For the CT69000 and SMI_LYNXEM drivers, videomode is
1297 selected via environment 'videomode'. Two different ways
1299 - "videomode=num" 'num' is a standard LiLo mode numbers.
1300 Following standard modes are supported (* is default):
1302 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1303 -------------+---------------------------------------------
1304 8 bits | 0x301* 0x303 0x305 0x161 0x307
1305 15 bits | 0x310 0x313 0x316 0x162 0x319
1306 16 bits | 0x311 0x314 0x317 0x163 0x31A
1307 24 bits | 0x312 0x315 0x318 ? 0x31B
1308 -------------+---------------------------------------------
1309 (i.e. setenv videomode 317; saveenv; reset;)
1311 - "videomode=bootargs" all the video parameters are parsed
1312 from the bootargs. (See drivers/video/videomodes.c)
1315 CONFIG_VIDEO_SED13806
1316 Enable Epson SED13806 driver. This driver supports 8bpp
1317 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1318 or CONFIG_VIDEO_SED13806_16BPP
1321 Enable the Freescale DIU video driver. Reference boards for
1322 SOCs that have a DIU should define this macro to enable DIU
1323 support, and should also define these other macros:
1329 CONFIG_VIDEO_SW_CURSOR
1330 CONFIG_VGA_AS_SINGLE_DEVICE
1332 CONFIG_VIDEO_BMP_LOGO
1334 The DIU driver will look for the 'video-mode' environment
1335 variable, and if defined, enable the DIU as a console during
1336 boot. See the documentation file README.video for a
1337 description of this variable.
1342 Define this to enable a custom keyboard support.
1343 This simply calls drv_keyboard_init() which must be
1344 defined in your board-specific files.
1345 The only board using this so far is RBC823.
1347 - LCD Support: CONFIG_LCD
1349 Define this to enable LCD support (for output to LCD
1350 display); also select one of the supported displays
1351 by defining one of these:
1355 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1357 CONFIG_NEC_NL6448AC33:
1359 NEC NL6448AC33-18. Active, color, single scan.
1361 CONFIG_NEC_NL6448BC20
1363 NEC NL6448BC20-08. 6.5", 640x480.
1364 Active, color, single scan.
1366 CONFIG_NEC_NL6448BC33_54
1368 NEC NL6448BC33-54. 10.4", 640x480.
1369 Active, color, single scan.
1373 Sharp 320x240. Active, color, single scan.
1374 It isn't 16x9, and I am not sure what it is.
1376 CONFIG_SHARP_LQ64D341
1378 Sharp LQ64D341 display, 640x480.
1379 Active, color, single scan.
1383 HLD1045 display, 640x480.
1384 Active, color, single scan.
1388 Optrex CBL50840-2 NF-FW 99 22 M5
1390 Hitachi LMG6912RPFC-00T
1394 320x240. Black & white.
1396 Normally display is black on white background; define
1397 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1399 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1401 If this option is set, the environment is checked for
1402 a variable "splashimage". If found, the usual display
1403 of logo, copyright and system information on the LCD
1404 is suppressed and the BMP image at the address
1405 specified in "splashimage" is loaded instead. The
1406 console is redirected to the "nulldev", too. This
1407 allows for a "silent" boot where a splash screen is
1408 loaded very quickly after power-on.
1410 CONFIG_SPLASH_SCREEN_ALIGN
1412 If this option is set the splash image can be freely positioned
1413 on the screen. Environment variable "splashpos" specifies the
1414 position as "x,y". If a positive number is given it is used as
1415 number of pixel from left/top. If a negative number is given it
1416 is used as number of pixel from right/bottom. You can also
1417 specify 'm' for centering the image.
1420 setenv splashpos m,m
1421 => image at center of screen
1423 setenv splashpos 30,20
1424 => image at x = 30 and y = 20
1426 setenv splashpos -10,m
1427 => vertically centered image
1428 at x = dspWidth - bmpWidth - 9
1430 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1432 If this option is set, additionally to standard BMP
1433 images, gzipped BMP images can be displayed via the
1434 splashscreen support or the bmp command.
1436 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1438 If this option is set, 8-bit RLE compressed BMP images
1439 can be displayed via the splashscreen support or the
1442 - Compression support:
1445 If this option is set, support for bzip2 compressed
1446 images is included. If not, only uncompressed and gzip
1447 compressed images are supported.
1449 NOTE: the bzip2 algorithm requires a lot of RAM, so
1450 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1455 If this option is set, support for lzma compressed
1458 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1459 requires an amount of dynamic memory that is given by the
1462 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1464 Where lc and lp stand for, respectively, Literal context bits
1465 and Literal pos bits.
1467 This value is upper-bounded by 14MB in the worst case. Anyway,
1468 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1469 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1470 a very small buffer.
1472 Use the lzmainfo tool to determinate the lc and lp values and
1473 then calculate the amount of needed dynamic memory (ensuring
1474 the appropriate CONFIG_SYS_MALLOC_LEN value).
1479 The address of PHY on MII bus.
1481 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1483 The clock frequency of the MII bus
1487 If this option is set, support for speed/duplex
1488 detection of gigabit PHY is included.
1490 CONFIG_PHY_RESET_DELAY
1492 Some PHY like Intel LXT971A need extra delay after
1493 reset before any MII register access is possible.
1494 For such PHY, set this option to the usec delay
1495 required. (minimum 300usec for LXT971A)
1497 CONFIG_PHY_CMD_DELAY (ppc4xx)
1499 Some PHY like Intel LXT971A need extra delay after
1500 command issued before MII status register can be read
1510 Define a default value for Ethernet address to use
1511 for the respective Ethernet interface, in case this
1512 is not determined automatically.
1517 Define a default value for the IP address to use for
1518 the default Ethernet interface, in case this is not
1519 determined through e.g. bootp.
1520 (Environment variable "ipaddr")
1522 - Server IP address:
1525 Defines a default value for the IP address of a TFTP
1526 server to contact when using the "tftboot" command.
1527 (Environment variable "serverip")
1529 CONFIG_KEEP_SERVERADDR
1531 Keeps the server's MAC address, in the env 'serveraddr'
1532 for passing to bootargs (like Linux's netconsole option)
1534 - Gateway IP address:
1537 Defines a default value for the IP address of the
1538 default router where packets to other networks are
1540 (Environment variable "gatewayip")
1545 Defines a default value for the subnet mask (or
1546 routing prefix) which is used to determine if an IP
1547 address belongs to the local subnet or needs to be
1548 forwarded through a router.
1549 (Environment variable "netmask")
1551 - Multicast TFTP Mode:
1554 Defines whether you want to support multicast TFTP as per
1555 rfc-2090; for example to work with atftp. Lets lots of targets
1556 tftp down the same boot image concurrently. Note: the Ethernet
1557 driver in use must provide a function: mcast() to join/leave a
1560 - BOOTP Recovery Mode:
1561 CONFIG_BOOTP_RANDOM_DELAY
1563 If you have many targets in a network that try to
1564 boot using BOOTP, you may want to avoid that all
1565 systems send out BOOTP requests at precisely the same
1566 moment (which would happen for instance at recovery
1567 from a power failure, when all systems will try to
1568 boot, thus flooding the BOOTP server. Defining
1569 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1570 inserted before sending out BOOTP requests. The
1571 following delays are inserted then:
1573 1st BOOTP request: delay 0 ... 1 sec
1574 2nd BOOTP request: delay 0 ... 2 sec
1575 3rd BOOTP request: delay 0 ... 4 sec
1577 BOOTP requests: delay 0 ... 8 sec
1579 - DHCP Advanced Options:
1580 You can fine tune the DHCP functionality by defining
1581 CONFIG_BOOTP_* symbols:
1583 CONFIG_BOOTP_SUBNETMASK
1584 CONFIG_BOOTP_GATEWAY
1585 CONFIG_BOOTP_HOSTNAME
1586 CONFIG_BOOTP_NISDOMAIN
1587 CONFIG_BOOTP_BOOTPATH
1588 CONFIG_BOOTP_BOOTFILESIZE
1591 CONFIG_BOOTP_SEND_HOSTNAME
1592 CONFIG_BOOTP_NTPSERVER
1593 CONFIG_BOOTP_TIMEOFFSET
1594 CONFIG_BOOTP_VENDOREX
1595 CONFIG_BOOTP_MAY_FAIL
1597 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1598 environment variable, not the BOOTP server.
1600 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1601 after the configured retry count, the call will fail
1602 instead of starting over. This can be used to fail over
1603 to Link-local IP address configuration if the DHCP server
1606 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1607 serverip from a DHCP server, it is possible that more
1608 than one DNS serverip is offered to the client.
1609 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1610 serverip will be stored in the additional environment
1611 variable "dnsip2". The first DNS serverip is always
1612 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1615 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1616 to do a dynamic update of a DNS server. To do this, they
1617 need the hostname of the DHCP requester.
1618 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1619 of the "hostname" environment variable is passed as
1620 option 12 to the DHCP server.
1622 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1624 A 32bit value in microseconds for a delay between
1625 receiving a "DHCP Offer" and sending the "DHCP Request".
1626 This fixes a problem with certain DHCP servers that don't
1627 respond 100% of the time to a "DHCP request". E.g. On an
1628 AT91RM9200 processor running at 180MHz, this delay needed
1629 to be *at least* 15,000 usec before a Windows Server 2003
1630 DHCP server would reply 100% of the time. I recommend at
1631 least 50,000 usec to be safe. The alternative is to hope
1632 that one of the retries will be successful but note that
1633 the DHCP timeout and retry process takes a longer than
1637 CONFIG_CDP_DEVICE_ID
1639 The device id used in CDP trigger frames.
1641 CONFIG_CDP_DEVICE_ID_PREFIX
1643 A two character string which is prefixed to the MAC address
1648 A printf format string which contains the ascii name of
1649 the port. Normally is set to "eth%d" which sets
1650 eth0 for the first Ethernet, eth1 for the second etc.
1652 CONFIG_CDP_CAPABILITIES
1654 A 32bit integer which indicates the device capabilities;
1655 0x00000010 for a normal host which does not forwards.
1659 An ascii string containing the version of the software.
1663 An ascii string containing the name of the platform.
1667 A 32bit integer sent on the trigger.
1669 CONFIG_CDP_POWER_CONSUMPTION
1671 A 16bit integer containing the power consumption of the
1672 device in .1 of milliwatts.
1674 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1676 A byte containing the id of the VLAN.
1678 - Status LED: CONFIG_STATUS_LED
1680 Several configurations allow to display the current
1681 status using a LED. For instance, the LED will blink
1682 fast while running U-Boot code, stop blinking as
1683 soon as a reply to a BOOTP request was received, and
1684 start blinking slow once the Linux kernel is running
1685 (supported by a status LED driver in the Linux
1686 kernel). Defining CONFIG_STATUS_LED enables this
1689 - CAN Support: CONFIG_CAN_DRIVER
1691 Defining CONFIG_CAN_DRIVER enables CAN driver support
1692 on those systems that support this (optional)
1693 feature, like the TQM8xxL modules.
1695 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1697 These enable I2C serial bus commands. Defining either of
1698 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1699 include the appropriate I2C driver for the selected CPU.
1701 This will allow you to use i2c commands at the u-boot
1702 command line (as long as you set CONFIG_CMD_I2C in
1703 CONFIG_COMMANDS) and communicate with i2c based realtime
1704 clock chips. See common/cmd_i2c.c for a description of the
1705 command line interface.
1707 CONFIG_HARD_I2C selects a hardware I2C controller.
1709 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1710 bit-banging) driver instead of CPM or similar hardware
1713 There are several other quantities that must also be
1714 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1716 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1717 to be the frequency (in Hz) at which you wish your i2c bus
1718 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1719 the CPU's i2c node address).
1721 Now, the u-boot i2c code for the mpc8xx
1722 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1723 and so its address should therefore be cleared to 0 (See,
1724 eg, MPC823e User's Manual p.16-473). So, set
1725 CONFIG_SYS_I2C_SLAVE to 0.
1727 CONFIG_SYS_I2C_INIT_MPC5XXX
1729 When a board is reset during an i2c bus transfer
1730 chips might think that the current transfer is still
1731 in progress. Reset the slave devices by sending start
1732 commands until the slave device responds.
1734 That's all that's required for CONFIG_HARD_I2C.
1736 If you use the software i2c interface (CONFIG_SOFT_I2C)
1737 then the following macros need to be defined (examples are
1738 from include/configs/lwmon.h):
1742 (Optional). Any commands necessary to enable the I2C
1743 controller or configure ports.
1745 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1749 (Only for MPC8260 CPU). The I/O port to use (the code
1750 assumes both bits are on the same port). Valid values
1751 are 0..3 for ports A..D.
1755 The code necessary to make the I2C data line active
1756 (driven). If the data line is open collector, this
1759 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1763 The code necessary to make the I2C data line tri-stated
1764 (inactive). If the data line is open collector, this
1767 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1771 Code that returns TRUE if the I2C data line is high,
1774 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1778 If <bit> is TRUE, sets the I2C data line high. If it
1779 is FALSE, it clears it (low).
1781 eg: #define I2C_SDA(bit) \
1782 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1783 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1787 If <bit> is TRUE, sets the I2C clock line high. If it
1788 is FALSE, it clears it (low).
1790 eg: #define I2C_SCL(bit) \
1791 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1792 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1796 This delay is invoked four times per clock cycle so this
1797 controls the rate of data transfer. The data rate thus
1798 is 1 / (I2C_DELAY * 4). Often defined to be something
1801 #define I2C_DELAY udelay(2)
1803 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1805 If your arch supports the generic GPIO framework (asm/gpio.h),
1806 then you may alternatively define the two GPIOs that are to be
1807 used as SCL / SDA. Any of the previous I2C_xxx macros will
1808 have GPIO-based defaults assigned to them as appropriate.
1810 You should define these to the GPIO value as given directly to
1811 the generic GPIO functions.
1813 CONFIG_SYS_I2C_INIT_BOARD
1815 When a board is reset during an i2c bus transfer
1816 chips might think that the current transfer is still
1817 in progress. On some boards it is possible to access
1818 the i2c SCLK line directly, either by using the
1819 processor pin as a GPIO or by having a second pin
1820 connected to the bus. If this option is defined a
1821 custom i2c_init_board() routine in boards/xxx/board.c
1822 is run early in the boot sequence.
1824 CONFIG_SYS_I2C_BOARD_LATE_INIT
1826 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1827 defined a custom i2c_board_late_init() routine in
1828 boards/xxx/board.c is run AFTER the operations in i2c_init()
1829 is completed. This callpoint can be used to unreset i2c bus
1830 using CPU i2c controller register accesses for CPUs whose i2c
1831 controller provide such a method. It is called at the end of
1832 i2c_init() to allow i2c_init operations to setup the i2c bus
1833 controller on the CPU (e.g. setting bus speed & slave address).
1835 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1837 This option enables configuration of bi_iic_fast[] flags
1838 in u-boot bd_info structure based on u-boot environment
1839 variable "i2cfast". (see also i2cfast)
1841 CONFIG_I2C_MULTI_BUS
1843 This option allows the use of multiple I2C buses, each of which
1844 must have a controller. At any point in time, only one bus is
1845 active. To switch to a different bus, use the 'i2c dev' command.
1846 Note that bus numbering is zero-based.
1848 CONFIG_SYS_I2C_NOPROBES
1850 This option specifies a list of I2C devices that will be skipped
1851 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1852 is set, specify a list of bus-device pairs. Otherwise, specify
1853 a 1D array of device addresses
1856 #undef CONFIG_I2C_MULTI_BUS
1857 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1859 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1861 #define CONFIG_I2C_MULTI_BUS
1862 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1864 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1866 CONFIG_SYS_SPD_BUS_NUM
1868 If defined, then this indicates the I2C bus number for DDR SPD.
1869 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1871 CONFIG_SYS_RTC_BUS_NUM
1873 If defined, then this indicates the I2C bus number for the RTC.
1874 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1876 CONFIG_SYS_DTT_BUS_NUM
1878 If defined, then this indicates the I2C bus number for the DTT.
1879 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1881 CONFIG_SYS_I2C_DTT_ADDR:
1883 If defined, specifies the I2C address of the DTT device.
1884 If not defined, then U-Boot uses predefined value for
1885 specified DTT device.
1889 Define this option if you want to use Freescale's I2C driver in
1890 drivers/i2c/fsl_i2c.c.
1894 Define this option if you have I2C devices reached over 1 .. n
1895 I2C Muxes like the pca9544a. This option addes a new I2C
1896 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1897 new I2C Bus to the existing I2C Busses. If you select the
1898 new Bus with "i2c dev", u-bbot sends first the commandos for
1899 the muxes to activate this new "bus".
1901 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1905 Adding a new I2C Bus reached over 2 pca9544a muxes
1906 The First mux with address 70 and channel 6
1907 The Second mux with address 71 and channel 4
1909 => i2c bus pca9544a:70:6:pca9544a:71:4
1911 Use the "i2c bus" command without parameter, to get a list
1912 of I2C Busses with muxes:
1915 Busses reached over muxes:
1917 reached over Mux(es):
1920 reached over Mux(es):
1925 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1926 u-boot first sends the command to the mux@70 to enable
1927 channel 6, and then the command to the mux@71 to enable
1930 After that, you can use the "normal" i2c commands as
1931 usual to communicate with your I2C devices behind
1934 This option is actually implemented for the bitbanging
1935 algorithm in common/soft_i2c.c and for the Hardware I2C
1936 Bus on the MPC8260. But it should be not so difficult
1937 to add this option to other architectures.
1939 CONFIG_SOFT_I2C_READ_REPEATED_START
1941 defining this will force the i2c_read() function in
1942 the soft_i2c driver to perform an I2C repeated start
1943 between writing the address pointer and reading the
1944 data. If this define is omitted the default behaviour
1945 of doing a stop-start sequence will be used. Most I2C
1946 devices can use either method, but some require one or
1949 - SPI Support: CONFIG_SPI
1951 Enables SPI driver (so far only tested with
1952 SPI EEPROM, also an instance works with Crystal A/D and
1953 D/As on the SACSng board)
1957 Enables the driver for SPI controller on SuperH. Currently
1958 only SH7757 is supported.
1962 Enables extended (16-bit) SPI EEPROM addressing.
1963 (symmetrical to CONFIG_I2C_X)
1967 Enables a software (bit-bang) SPI driver rather than
1968 using hardware support. This is a general purpose
1969 driver that only requires three general I/O port pins
1970 (two outputs, one input) to function. If this is
1971 defined, the board configuration must define several
1972 SPI configuration items (port pins to use, etc). For
1973 an example, see include/configs/sacsng.h.
1977 Enables a hardware SPI driver for general-purpose reads
1978 and writes. As with CONFIG_SOFT_SPI, the board configuration
1979 must define a list of chip-select function pointers.
1980 Currently supported on some MPC8xxx processors. For an
1981 example, see include/configs/mpc8349emds.h.
1985 Enables the driver for the SPI controllers on i.MX and MXC
1986 SoCs. Currently i.MX31/35/51 are supported.
1988 - FPGA Support: CONFIG_FPGA
1990 Enables FPGA subsystem.
1992 CONFIG_FPGA_<vendor>
1994 Enables support for specific chip vendors.
1997 CONFIG_FPGA_<family>
1999 Enables support for FPGA family.
2000 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2004 Specify the number of FPGA devices to support.
2006 CONFIG_SYS_FPGA_PROG_FEEDBACK
2008 Enable printing of hash marks during FPGA configuration.
2010 CONFIG_SYS_FPGA_CHECK_BUSY
2012 Enable checks on FPGA configuration interface busy
2013 status by the configuration function. This option
2014 will require a board or device specific function to
2019 If defined, a function that provides delays in the FPGA
2020 configuration driver.
2022 CONFIG_SYS_FPGA_CHECK_CTRLC
2023 Allow Control-C to interrupt FPGA configuration
2025 CONFIG_SYS_FPGA_CHECK_ERROR
2027 Check for configuration errors during FPGA bitfile
2028 loading. For example, abort during Virtex II
2029 configuration if the INIT_B line goes low (which
2030 indicated a CRC error).
2032 CONFIG_SYS_FPGA_WAIT_INIT
2034 Maximum time to wait for the INIT_B line to deassert
2035 after PROB_B has been deasserted during a Virtex II
2036 FPGA configuration sequence. The default time is 500
2039 CONFIG_SYS_FPGA_WAIT_BUSY
2041 Maximum time to wait for BUSY to deassert during
2042 Virtex II FPGA configuration. The default is 5 ms.
2044 CONFIG_SYS_FPGA_WAIT_CONFIG
2046 Time to wait after FPGA configuration. The default is
2049 - Configuration Management:
2052 If defined, this string will be added to the U-Boot
2053 version information (U_BOOT_VERSION)
2055 - Vendor Parameter Protection:
2057 U-Boot considers the values of the environment
2058 variables "serial#" (Board Serial Number) and
2059 "ethaddr" (Ethernet Address) to be parameters that
2060 are set once by the board vendor / manufacturer, and
2061 protects these variables from casual modification by
2062 the user. Once set, these variables are read-only,
2063 and write or delete attempts are rejected. You can
2064 change this behaviour:
2066 If CONFIG_ENV_OVERWRITE is #defined in your config
2067 file, the write protection for vendor parameters is
2068 completely disabled. Anybody can change or delete
2071 Alternatively, if you #define _both_ CONFIG_ETHADDR
2072 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2073 Ethernet address is installed in the environment,
2074 which can be changed exactly ONCE by the user. [The
2075 serial# is unaffected by this, i. e. it remains
2081 Define this variable to enable the reservation of
2082 "protected RAM", i. e. RAM which is not overwritten
2083 by U-Boot. Define CONFIG_PRAM to hold the number of
2084 kB you want to reserve for pRAM. You can overwrite
2085 this default value by defining an environment
2086 variable "pram" to the number of kB you want to
2087 reserve. Note that the board info structure will
2088 still show the full amount of RAM. If pRAM is
2089 reserved, a new environment variable "mem" will
2090 automatically be defined to hold the amount of
2091 remaining RAM in a form that can be passed as boot
2092 argument to Linux, for instance like that:
2094 setenv bootargs ... mem=\${mem}
2097 This way you can tell Linux not to use this memory,
2098 either, which results in a memory region that will
2099 not be affected by reboots.
2101 *WARNING* If your board configuration uses automatic
2102 detection of the RAM size, you must make sure that
2103 this memory test is non-destructive. So far, the
2104 following board configurations are known to be
2107 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2108 HERMES, IP860, RPXlite, LWMON, LANTEC,
2114 Define this variable to stop the system in case of a
2115 fatal error, so that you have to reset it manually.
2116 This is probably NOT a good idea for an embedded
2117 system where you want the system to reboot
2118 automatically as fast as possible, but it may be
2119 useful during development since you can try to debug
2120 the conditions that lead to the situation.
2122 CONFIG_NET_RETRY_COUNT
2124 This variable defines the number of retries for
2125 network operations like ARP, RARP, TFTP, or BOOTP
2126 before giving up the operation. If not defined, a
2127 default value of 5 is used.
2131 Timeout waiting for an ARP reply in milliseconds.
2133 - Command Interpreter:
2134 CONFIG_AUTO_COMPLETE
2136 Enable auto completion of commands using TAB.
2138 Note that this feature has NOT been implemented yet
2139 for the "hush" shell.
2142 CONFIG_SYS_HUSH_PARSER
2144 Define this variable to enable the "hush" shell (from
2145 Busybox) as command line interpreter, thus enabling
2146 powerful command line syntax like
2147 if...then...else...fi conditionals or `&&' and '||'
2148 constructs ("shell scripts").
2150 If undefined, you get the old, much simpler behaviour
2151 with a somewhat smaller memory footprint.
2154 CONFIG_SYS_PROMPT_HUSH_PS2
2156 This defines the secondary prompt string, which is
2157 printed when the command interpreter needs more input
2158 to complete a command. Usually "> ".
2162 In the current implementation, the local variables
2163 space and global environment variables space are
2164 separated. Local variables are those you define by
2165 simply typing `name=value'. To access a local
2166 variable later on, you have write `$name' or
2167 `${name}'; to execute the contents of a variable
2168 directly type `$name' at the command prompt.
2170 Global environment variables are those you use
2171 setenv/printenv to work with. To run a command stored
2172 in such a variable, you need to use the run command,
2173 and you must not use the '$' sign to access them.
2175 To store commands and special characters in a
2176 variable, please use double quotation marks
2177 surrounding the whole text of the variable, instead
2178 of the backslashes before semicolons and special
2181 - Commandline Editing and History:
2182 CONFIG_CMDLINE_EDITING
2184 Enable editing and History functions for interactive
2185 commandline input operations
2187 - Default Environment:
2188 CONFIG_EXTRA_ENV_SETTINGS
2190 Define this to contain any number of null terminated
2191 strings (variable = value pairs) that will be part of
2192 the default environment compiled into the boot image.
2194 For example, place something like this in your
2195 board's config file:
2197 #define CONFIG_EXTRA_ENV_SETTINGS \
2201 Warning: This method is based on knowledge about the
2202 internal format how the environment is stored by the
2203 U-Boot code. This is NOT an official, exported
2204 interface! Although it is unlikely that this format
2205 will change soon, there is no guarantee either.
2206 You better know what you are doing here.
2208 Note: overly (ab)use of the default environment is
2209 discouraged. Make sure to check other ways to preset
2210 the environment like the "source" command or the
2213 - DataFlash Support:
2214 CONFIG_HAS_DATAFLASH
2216 Defining this option enables DataFlash features and
2217 allows to read/write in Dataflash via the standard
2220 - Serial Flash support
2223 Defining this option enables SPI flash commands
2224 'sf probe/read/write/erase/update'.
2226 Usage requires an initial 'probe' to define the serial
2227 flash parameters, followed by read/write/erase/update
2230 The following defaults may be provided by the platform
2231 to handle the common case when only a single serial
2232 flash is present on the system.
2234 CONFIG_SF_DEFAULT_BUS Bus identifier
2235 CONFIG_SF_DEFAULT_CS Chip-select
2236 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2237 CONFIG_SF_DEFAULT_SPEED in Hz
2239 - SystemACE Support:
2242 Adding this option adds support for Xilinx SystemACE
2243 chips attached via some sort of local bus. The address
2244 of the chip must also be defined in the
2245 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2247 #define CONFIG_SYSTEMACE
2248 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2250 When SystemACE support is added, the "ace" device type
2251 becomes available to the fat commands, i.e. fatls.
2253 - TFTP Fixed UDP Port:
2256 If this is defined, the environment variable tftpsrcp
2257 is used to supply the TFTP UDP source port value.
2258 If tftpsrcp isn't defined, the normal pseudo-random port
2259 number generator is used.
2261 Also, the environment variable tftpdstp is used to supply
2262 the TFTP UDP destination port value. If tftpdstp isn't
2263 defined, the normal port 69 is used.
2265 The purpose for tftpsrcp is to allow a TFTP server to
2266 blindly start the TFTP transfer using the pre-configured
2267 target IP address and UDP port. This has the effect of
2268 "punching through" the (Windows XP) firewall, allowing
2269 the remainder of the TFTP transfer to proceed normally.
2270 A better solution is to properly configure the firewall,
2271 but sometimes that is not allowed.
2273 - Show boot progress:
2274 CONFIG_SHOW_BOOT_PROGRESS
2276 Defining this option allows to add some board-
2277 specific code (calling a user-provided function
2278 "show_boot_progress(int)") that enables you to show
2279 the system's boot progress on some display (for
2280 example, some LED's) on your board. At the moment,
2281 the following checkpoints are implemented:
2283 - Detailed boot stage timing
2285 Define this option to get detailed timing of each stage
2286 of the boot process.
2288 CONFIG_BOOTSTAGE_USER_COUNT
2289 This is the number of available user bootstage records.
2290 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2291 a new ID will be allocated from this stash. If you exceed
2292 the limit, recording will stop.
2294 CONFIG_BOOTSTAGE_REPORT
2295 Define this to print a report before boot, similar to this:
2297 Timer summary in microseconds:
2300 3,575,678 3,575,678 board_init_f start
2301 3,575,695 17 arch_cpu_init A9
2302 3,575,777 82 arch_cpu_init done
2303 3,659,598 83,821 board_init_r start
2304 3,910,375 250,777 main_loop
2305 29,916,167 26,005,792 bootm_start
2306 30,361,327 445,160 start_kernel
2308 Legacy uImage format:
2311 1 common/cmd_bootm.c before attempting to boot an image
2312 -1 common/cmd_bootm.c Image header has bad magic number
2313 2 common/cmd_bootm.c Image header has correct magic number
2314 -2 common/cmd_bootm.c Image header has bad checksum
2315 3 common/cmd_bootm.c Image header has correct checksum
2316 -3 common/cmd_bootm.c Image data has bad checksum
2317 4 common/cmd_bootm.c Image data has correct checksum
2318 -4 common/cmd_bootm.c Image is for unsupported architecture
2319 5 common/cmd_bootm.c Architecture check OK
2320 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2321 6 common/cmd_bootm.c Image Type check OK
2322 -6 common/cmd_bootm.c gunzip uncompression error
2323 -7 common/cmd_bootm.c Unimplemented compression type
2324 7 common/cmd_bootm.c Uncompression OK
2325 8 common/cmd_bootm.c No uncompress/copy overwrite error
2326 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2328 9 common/image.c Start initial ramdisk verification
2329 -10 common/image.c Ramdisk header has bad magic number
2330 -11 common/image.c Ramdisk header has bad checksum
2331 10 common/image.c Ramdisk header is OK
2332 -12 common/image.c Ramdisk data has bad checksum
2333 11 common/image.c Ramdisk data has correct checksum
2334 12 common/image.c Ramdisk verification complete, start loading
2335 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2336 13 common/image.c Start multifile image verification
2337 14 common/image.c No initial ramdisk, no multifile, continue.
2339 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2341 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2342 -31 post/post.c POST test failed, detected by post_output_backlog()
2343 -32 post/post.c POST test failed, detected by post_run_single()
2345 34 common/cmd_doc.c before loading a Image from a DOC device
2346 -35 common/cmd_doc.c Bad usage of "doc" command
2347 35 common/cmd_doc.c correct usage of "doc" command
2348 -36 common/cmd_doc.c No boot device
2349 36 common/cmd_doc.c correct boot device
2350 -37 common/cmd_doc.c Unknown Chip ID on boot device
2351 37 common/cmd_doc.c correct chip ID found, device available
2352 -38 common/cmd_doc.c Read Error on boot device
2353 38 common/cmd_doc.c reading Image header from DOC device OK
2354 -39 common/cmd_doc.c Image header has bad magic number
2355 39 common/cmd_doc.c Image header has correct magic number
2356 -40 common/cmd_doc.c Error reading Image from DOC device
2357 40 common/cmd_doc.c Image header has correct magic number
2358 41 common/cmd_ide.c before loading a Image from a IDE device
2359 -42 common/cmd_ide.c Bad usage of "ide" command
2360 42 common/cmd_ide.c correct usage of "ide" command
2361 -43 common/cmd_ide.c No boot device
2362 43 common/cmd_ide.c boot device found
2363 -44 common/cmd_ide.c Device not available
2364 44 common/cmd_ide.c Device available
2365 -45 common/cmd_ide.c wrong partition selected
2366 45 common/cmd_ide.c partition selected
2367 -46 common/cmd_ide.c Unknown partition table
2368 46 common/cmd_ide.c valid partition table found
2369 -47 common/cmd_ide.c Invalid partition type
2370 47 common/cmd_ide.c correct partition type
2371 -48 common/cmd_ide.c Error reading Image Header on boot device
2372 48 common/cmd_ide.c reading Image Header from IDE device OK
2373 -49 common/cmd_ide.c Image header has bad magic number
2374 49 common/cmd_ide.c Image header has correct magic number
2375 -50 common/cmd_ide.c Image header has bad checksum
2376 50 common/cmd_ide.c Image header has correct checksum
2377 -51 common/cmd_ide.c Error reading Image from IDE device
2378 51 common/cmd_ide.c reading Image from IDE device OK
2379 52 common/cmd_nand.c before loading a Image from a NAND device
2380 -53 common/cmd_nand.c Bad usage of "nand" command
2381 53 common/cmd_nand.c correct usage of "nand" command
2382 -54 common/cmd_nand.c No boot device
2383 54 common/cmd_nand.c boot device found
2384 -55 common/cmd_nand.c Unknown Chip ID on boot device
2385 55 common/cmd_nand.c correct chip ID found, device available
2386 -56 common/cmd_nand.c Error reading Image Header on boot device
2387 56 common/cmd_nand.c reading Image Header from NAND device OK
2388 -57 common/cmd_nand.c Image header has bad magic number
2389 57 common/cmd_nand.c Image header has correct magic number
2390 -58 common/cmd_nand.c Error reading Image from NAND device
2391 58 common/cmd_nand.c reading Image from NAND device OK
2393 -60 common/env_common.c Environment has a bad CRC, using default
2395 64 net/eth.c starting with Ethernet configuration.
2396 -64 net/eth.c no Ethernet found.
2397 65 net/eth.c Ethernet found.
2399 -80 common/cmd_net.c usage wrong
2400 80 common/cmd_net.c before calling NetLoop()
2401 -81 common/cmd_net.c some error in NetLoop() occurred
2402 81 common/cmd_net.c NetLoop() back without error
2403 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2404 82 common/cmd_net.c trying automatic boot
2405 83 common/cmd_net.c running "source" command
2406 -83 common/cmd_net.c some error in automatic boot or "source" command
2407 84 common/cmd_net.c end without errors
2412 100 common/cmd_bootm.c Kernel FIT Image has correct format
2413 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2414 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2415 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2416 102 common/cmd_bootm.c Kernel unit name specified
2417 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2418 103 common/cmd_bootm.c Found configuration node
2419 104 common/cmd_bootm.c Got kernel subimage node offset
2420 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2421 105 common/cmd_bootm.c Kernel subimage hash verification OK
2422 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2423 106 common/cmd_bootm.c Architecture check OK
2424 -106 common/cmd_bootm.c Kernel subimage has wrong type
2425 107 common/cmd_bootm.c Kernel subimage type OK
2426 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2427 108 common/cmd_bootm.c Got kernel subimage data/size
2428 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2429 -109 common/cmd_bootm.c Can't get kernel subimage type
2430 -110 common/cmd_bootm.c Can't get kernel subimage comp
2431 -111 common/cmd_bootm.c Can't get kernel subimage os
2432 -112 common/cmd_bootm.c Can't get kernel subimage load address
2433 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2435 120 common/image.c Start initial ramdisk verification
2436 -120 common/image.c Ramdisk FIT image has incorrect format
2437 121 common/image.c Ramdisk FIT image has correct format
2438 122 common/image.c No ramdisk subimage unit name, using configuration
2439 -122 common/image.c Can't get configuration for ramdisk subimage
2440 123 common/image.c Ramdisk unit name specified
2441 -124 common/image.c Can't get ramdisk subimage node offset
2442 125 common/image.c Got ramdisk subimage node offset
2443 -125 common/image.c Ramdisk subimage hash verification failed
2444 126 common/image.c Ramdisk subimage hash verification OK
2445 -126 common/image.c Ramdisk subimage for unsupported architecture
2446 127 common/image.c Architecture check OK
2447 -127 common/image.c Can't get ramdisk subimage data/size
2448 128 common/image.c Got ramdisk subimage data/size
2449 129 common/image.c Can't get ramdisk load address
2450 -129 common/image.c Got ramdisk load address
2452 -130 common/cmd_doc.c Incorrect FIT image format
2453 131 common/cmd_doc.c FIT image format OK
2455 -140 common/cmd_ide.c Incorrect FIT image format
2456 141 common/cmd_ide.c FIT image format OK
2458 -150 common/cmd_nand.c Incorrect FIT image format
2459 151 common/cmd_nand.c FIT image format OK
2461 - Standalone program support:
2462 CONFIG_STANDALONE_LOAD_ADDR
2464 This option defines a board specific value for the
2465 address where standalone program gets loaded, thus
2466 overwriting the architecture dependent default
2469 - Frame Buffer Address:
2472 Define CONFIG_FB_ADDR if you want to use specific
2473 address for frame buffer.
2474 Then system will reserve the frame buffer address to
2475 defined address instead of lcd_setmem (this function
2476 grabs the memory for frame buffer by panel's size).
2478 Please see board_init_f function.
2480 - Automatic software updates via TFTP server
2482 CONFIG_UPDATE_TFTP_CNT_MAX
2483 CONFIG_UPDATE_TFTP_MSEC_MAX
2485 These options enable and control the auto-update feature;
2486 for a more detailed description refer to doc/README.update.
2488 - MTD Support (mtdparts command, UBI support)
2491 Adds the MTD device infrastructure from the Linux kernel.
2492 Needed for mtdparts command support.
2494 CONFIG_MTD_PARTITIONS
2496 Adds the MTD partitioning infrastructure from the Linux
2497 kernel. Needed for UBI support.
2501 Enable building of SPL globally.
2504 LDSCRIPT for linking the SPL binary.
2507 Maximum binary size (text, data and rodata) of the SPL binary.
2509 CONFIG_SPL_TEXT_BASE
2510 TEXT_BASE for linking the SPL binary.
2512 CONFIG_SPL_BSS_START_ADDR
2513 Link address for the BSS within the SPL binary.
2515 CONFIG_SPL_BSS_MAX_SIZE
2516 Maximum binary size of the BSS section of the SPL binary.
2519 Adress of the start of the stack SPL will use
2521 CONFIG_SYS_SPL_MALLOC_START
2522 Starting address of the malloc pool used in SPL.
2524 CONFIG_SYS_SPL_MALLOC_SIZE
2525 The size of the malloc pool used in SPL.
2527 CONFIG_SPL_LIBCOMMON_SUPPORT
2528 Support for common/libcommon.o in SPL binary
2530 CONFIG_SPL_LIBDISK_SUPPORT
2531 Support for disk/libdisk.o in SPL binary
2533 CONFIG_SPL_I2C_SUPPORT
2534 Support for drivers/i2c/libi2c.o in SPL binary
2536 CONFIG_SPL_GPIO_SUPPORT
2537 Support for drivers/gpio/libgpio.o in SPL binary
2539 CONFIG_SPL_MMC_SUPPORT
2540 Support for drivers/mmc/libmmc.o in SPL binary
2542 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2543 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2544 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2545 Address, size and partition on the MMC to load U-Boot from
2546 when the MMC is being used in raw mode.
2548 CONFIG_SPL_FAT_SUPPORT
2549 Support for fs/fat/libfat.o in SPL binary
2551 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2552 Filename to read to load U-Boot when reading from FAT
2554 CONFIG_SPL_NAND_SIMPLE
2555 Support for drivers/mtd/nand/libnand.o in SPL binary
2557 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2558 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2559 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2560 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2561 CONFIG_SYS_NAND_ECCBYTES
2562 Defines the size and behavior of the NAND that SPL uses
2563 to read U-Boot with CONFIG_SPL_NAND_SIMPLE
2565 CONFIG_SYS_NAND_U_BOOT_OFFS
2566 Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
2569 CONFIG_SYS_NAND_U_BOOT_START
2570 Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
2573 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2574 Define this if you need to first read the OOB and then the
2575 data. This is used for example on davinci plattforms.
2577 CONFIG_SPL_OMAP3_ID_NAND
2578 Support for an OMAP3-specific set of functions to return the
2579 ID and MFR of the first attached NAND chip, if present.
2581 CONFIG_SPL_SERIAL_SUPPORT
2582 Support for drivers/serial/libserial.o in SPL binary
2584 CONFIG_SPL_SPI_FLASH_SUPPORT
2585 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2587 CONFIG_SPL_SPI_SUPPORT
2588 Support for drivers/spi/libspi.o in SPL binary
2590 CONFIG_SPL_LIBGENERIC_SUPPORT
2591 Support for lib/libgeneric.o in SPL binary
2596 [so far only for SMDK2400 boards]
2598 - Modem support enable:
2599 CONFIG_MODEM_SUPPORT
2601 - RTS/CTS Flow control enable:
2604 - Modem debug support:
2605 CONFIG_MODEM_SUPPORT_DEBUG
2607 Enables debugging stuff (char screen[1024], dbg())
2608 for modem support. Useful only with BDI2000.
2610 - Interrupt support (PPC):
2612 There are common interrupt_init() and timer_interrupt()
2613 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2614 for CPU specific initialization. interrupt_init_cpu()
2615 should set decrementer_count to appropriate value. If
2616 CPU resets decrementer automatically after interrupt
2617 (ppc4xx) it should set decrementer_count to zero.
2618 timer_interrupt() calls timer_interrupt_cpu() for CPU
2619 specific handling. If board has watchdog / status_led
2620 / other_activity_monitor it works automatically from
2621 general timer_interrupt().
2625 In the target system modem support is enabled when a
2626 specific key (key combination) is pressed during
2627 power-on. Otherwise U-Boot will boot normally
2628 (autoboot). The key_pressed() function is called from
2629 board_init(). Currently key_pressed() is a dummy
2630 function, returning 1 and thus enabling modem
2633 If there are no modem init strings in the
2634 environment, U-Boot proceed to autoboot; the
2635 previous output (banner, info printfs) will be
2638 See also: doc/README.Modem
2640 Board initialization settings:
2641 ------------------------------
2643 During Initialization u-boot calls a number of board specific functions
2644 to allow the preparation of board specific prerequisites, e.g. pin setup
2645 before drivers are initialized. To enable these callbacks the
2646 following configuration macros have to be defined. Currently this is
2647 architecture specific, so please check arch/your_architecture/lib/board.c
2648 typically in board_init_f() and board_init_r().
2650 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2651 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2652 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2653 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2655 Configuration Settings:
2656 -----------------------
2658 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2659 undefine this when you're short of memory.
2661 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2662 width of the commands listed in the 'help' command output.
2664 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2665 prompt for user input.
2667 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2669 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2671 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2673 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2674 the application (usually a Linux kernel) when it is
2677 - CONFIG_SYS_BAUDRATE_TABLE:
2678 List of legal baudrate settings for this board.
2680 - CONFIG_SYS_CONSOLE_INFO_QUIET
2681 Suppress display of console information at boot.
2683 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2684 If the board specific function
2685 extern int overwrite_console (void);
2686 returns 1, the stdin, stderr and stdout are switched to the
2687 serial port, else the settings in the environment are used.
2689 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2690 Enable the call to overwrite_console().
2692 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2693 Enable overwrite of previous console environment settings.
2695 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2696 Begin and End addresses of the area used by the
2699 - CONFIG_SYS_ALT_MEMTEST:
2700 Enable an alternate, more extensive memory test.
2702 - CONFIG_SYS_MEMTEST_SCRATCH:
2703 Scratch address used by the alternate memory test
2704 You only need to set this if address zero isn't writeable
2706 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2707 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2708 this specified memory area will get subtracted from the top
2709 (end) of RAM and won't get "touched" at all by U-Boot. By
2710 fixing up gd->ram_size the Linux kernel should gets passed
2711 the now "corrected" memory size and won't touch it either.
2712 This should work for arch/ppc and arch/powerpc. Only Linux
2713 board ports in arch/powerpc with bootwrapper support that
2714 recalculate the memory size from the SDRAM controller setup
2715 will have to get fixed in Linux additionally.
2717 This option can be used as a workaround for the 440EPx/GRx
2718 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2721 WARNING: Please make sure that this value is a multiple of
2722 the Linux page size (normally 4k). If this is not the case,
2723 then the end address of the Linux memory will be located at a
2724 non page size aligned address and this could cause major
2727 - CONFIG_SYS_TFTP_LOADADDR:
2728 Default load address for network file downloads
2730 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2731 Enable temporary baudrate change while serial download
2733 - CONFIG_SYS_SDRAM_BASE:
2734 Physical start address of SDRAM. _Must_ be 0 here.
2736 - CONFIG_SYS_MBIO_BASE:
2737 Physical start address of Motherboard I/O (if using a
2740 - CONFIG_SYS_FLASH_BASE:
2741 Physical start address of Flash memory.
2743 - CONFIG_SYS_MONITOR_BASE:
2744 Physical start address of boot monitor code (set by
2745 make config files to be same as the text base address
2746 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2747 CONFIG_SYS_FLASH_BASE when booting from flash.
2749 - CONFIG_SYS_MONITOR_LEN:
2750 Size of memory reserved for monitor code, used to
2751 determine _at_compile_time_ (!) if the environment is
2752 embedded within the U-Boot image, or in a separate
2755 - CONFIG_SYS_MALLOC_LEN:
2756 Size of DRAM reserved for malloc() use.
2758 - CONFIG_SYS_BOOTM_LEN:
2759 Normally compressed uImages are limited to an
2760 uncompressed size of 8 MBytes. If this is not enough,
2761 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2762 to adjust this setting to your needs.
2764 - CONFIG_SYS_BOOTMAPSZ:
2765 Maximum size of memory mapped by the startup code of
2766 the Linux kernel; all data that must be processed by
2767 the Linux kernel (bd_info, boot arguments, FDT blob if
2768 used) must be put below this limit, unless "bootm_low"
2769 enviroment variable is defined and non-zero. In such case
2770 all data for the Linux kernel must be between "bootm_low"
2771 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2772 variable "bootm_mapsize" will override the value of
2773 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2774 then the value in "bootm_size" will be used instead.
2776 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2777 Enable initrd_high functionality. If defined then the
2778 initrd_high feature is enabled and the bootm ramdisk subcommand
2781 - CONFIG_SYS_BOOT_GET_CMDLINE:
2782 Enables allocating and saving kernel cmdline in space between
2783 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2785 - CONFIG_SYS_BOOT_GET_KBD:
2786 Enables allocating and saving a kernel copy of the bd_info in
2787 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2789 - CONFIG_SYS_MAX_FLASH_BANKS:
2790 Max number of Flash memory banks
2792 - CONFIG_SYS_MAX_FLASH_SECT:
2793 Max number of sectors on a Flash chip
2795 - CONFIG_SYS_FLASH_ERASE_TOUT:
2796 Timeout for Flash erase operations (in ms)
2798 - CONFIG_SYS_FLASH_WRITE_TOUT:
2799 Timeout for Flash write operations (in ms)
2801 - CONFIG_SYS_FLASH_LOCK_TOUT
2802 Timeout for Flash set sector lock bit operation (in ms)
2804 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2805 Timeout for Flash clear lock bits operation (in ms)
2807 - CONFIG_SYS_FLASH_PROTECTION
2808 If defined, hardware flash sectors protection is used
2809 instead of U-Boot software protection.
2811 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2813 Enable TFTP transfers directly to flash memory;
2814 without this option such a download has to be
2815 performed in two steps: (1) download to RAM, and (2)
2816 copy from RAM to flash.
2818 The two-step approach is usually more reliable, since
2819 you can check if the download worked before you erase
2820 the flash, but in some situations (when system RAM is
2821 too limited to allow for a temporary copy of the
2822 downloaded image) this option may be very useful.
2824 - CONFIG_SYS_FLASH_CFI:
2825 Define if the flash driver uses extra elements in the
2826 common flash structure for storing flash geometry.
2828 - CONFIG_FLASH_CFI_DRIVER
2829 This option also enables the building of the cfi_flash driver
2830 in the drivers directory
2832 - CONFIG_FLASH_CFI_MTD
2833 This option enables the building of the cfi_mtd driver
2834 in the drivers directory. The driver exports CFI flash
2837 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2838 Use buffered writes to flash.
2840 - CONFIG_FLASH_SPANSION_S29WS_N
2841 s29ws-n MirrorBit flash has non-standard addresses for buffered
2844 - CONFIG_SYS_FLASH_QUIET_TEST
2845 If this option is defined, the common CFI flash doesn't
2846 print it's warning upon not recognized FLASH banks. This
2847 is useful, if some of the configured banks are only
2848 optionally available.
2850 - CONFIG_FLASH_SHOW_PROGRESS
2851 If defined (must be an integer), print out countdown
2852 digits and dots. Recommended value: 45 (9..1) for 80
2853 column displays, 15 (3..1) for 40 column displays.
2855 - CONFIG_SYS_RX_ETH_BUFFER:
2856 Defines the number of Ethernet receive buffers. On some
2857 Ethernet controllers it is recommended to set this value
2858 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2859 buffers can be full shortly after enabling the interface
2860 on high Ethernet traffic.
2861 Defaults to 4 if not defined.
2863 - CONFIG_ENV_MAX_ENTRIES
2865 Maximum number of entries in the hash table that is used
2866 internally to store the environment settings. The default
2867 setting is supposed to be generous and should work in most
2868 cases. This setting can be used to tune behaviour; see
2869 lib/hashtable.c for details.
2871 The following definitions that deal with the placement and management
2872 of environment data (variable area); in general, we support the
2873 following configurations:
2875 - CONFIG_BUILD_ENVCRC:
2877 Builds up envcrc with the target environment so that external utils
2878 may easily extract it and embed it in final U-Boot images.
2880 - CONFIG_ENV_IS_IN_FLASH:
2882 Define this if the environment is in flash memory.
2884 a) The environment occupies one whole flash sector, which is
2885 "embedded" in the text segment with the U-Boot code. This
2886 happens usually with "bottom boot sector" or "top boot
2887 sector" type flash chips, which have several smaller
2888 sectors at the start or the end. For instance, such a
2889 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2890 such a case you would place the environment in one of the
2891 4 kB sectors - with U-Boot code before and after it. With
2892 "top boot sector" type flash chips, you would put the
2893 environment in one of the last sectors, leaving a gap
2894 between U-Boot and the environment.
2896 - CONFIG_ENV_OFFSET:
2898 Offset of environment data (variable area) to the
2899 beginning of flash memory; for instance, with bottom boot
2900 type flash chips the second sector can be used: the offset
2901 for this sector is given here.
2903 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2907 This is just another way to specify the start address of
2908 the flash sector containing the environment (instead of
2911 - CONFIG_ENV_SECT_SIZE:
2913 Size of the sector containing the environment.
2916 b) Sometimes flash chips have few, equal sized, BIG sectors.
2917 In such a case you don't want to spend a whole sector for
2922 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2923 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2924 of this flash sector for the environment. This saves
2925 memory for the RAM copy of the environment.
2927 It may also save flash memory if you decide to use this
2928 when your environment is "embedded" within U-Boot code,
2929 since then the remainder of the flash sector could be used
2930 for U-Boot code. It should be pointed out that this is
2931 STRONGLY DISCOURAGED from a robustness point of view:
2932 updating the environment in flash makes it always
2933 necessary to erase the WHOLE sector. If something goes
2934 wrong before the contents has been restored from a copy in
2935 RAM, your target system will be dead.
2937 - CONFIG_ENV_ADDR_REDUND
2938 CONFIG_ENV_SIZE_REDUND
2940 These settings describe a second storage area used to hold
2941 a redundant copy of the environment data, so that there is
2942 a valid backup copy in case there is a power failure during
2943 a "saveenv" operation.
2945 BE CAREFUL! Any changes to the flash layout, and some changes to the
2946 source code will make it necessary to adapt <board>/u-boot.lds*
2950 - CONFIG_ENV_IS_IN_NVRAM:
2952 Define this if you have some non-volatile memory device
2953 (NVRAM, battery buffered SRAM) which you want to use for the
2959 These two #defines are used to determine the memory area you
2960 want to use for environment. It is assumed that this memory
2961 can just be read and written to, without any special
2964 BE CAREFUL! The first access to the environment happens quite early
2965 in U-Boot initalization (when we try to get the setting of for the
2966 console baudrate). You *MUST* have mapped your NVRAM area then, or
2969 Please note that even with NVRAM we still use a copy of the
2970 environment in RAM: we could work on NVRAM directly, but we want to
2971 keep settings there always unmodified except somebody uses "saveenv"
2972 to save the current settings.
2975 - CONFIG_ENV_IS_IN_EEPROM:
2977 Use this if you have an EEPROM or similar serial access
2978 device and a driver for it.
2980 - CONFIG_ENV_OFFSET:
2983 These two #defines specify the offset and size of the
2984 environment area within the total memory of your EEPROM.
2986 - CONFIG_SYS_I2C_EEPROM_ADDR:
2987 If defined, specified the chip address of the EEPROM device.
2988 The default address is zero.
2990 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2991 If defined, the number of bits used to address bytes in a
2992 single page in the EEPROM device. A 64 byte page, for example
2993 would require six bits.
2995 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2996 If defined, the number of milliseconds to delay between
2997 page writes. The default is zero milliseconds.
2999 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3000 The length in bytes of the EEPROM memory array address. Note
3001 that this is NOT the chip address length!
3003 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3004 EEPROM chips that implement "address overflow" are ones
3005 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3006 address and the extra bits end up in the "chip address" bit
3007 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3010 Note that we consider the length of the address field to
3011 still be one byte because the extra address bits are hidden
3012 in the chip address.
3014 - CONFIG_SYS_EEPROM_SIZE:
3015 The size in bytes of the EEPROM device.
3017 - CONFIG_ENV_EEPROM_IS_ON_I2C
3018 define this, if you have I2C and SPI activated, and your
3019 EEPROM, which holds the environment, is on the I2C bus.
3021 - CONFIG_I2C_ENV_EEPROM_BUS
3022 if you have an Environment on an EEPROM reached over
3023 I2C muxes, you can define here, how to reach this
3024 EEPROM. For example:
3026 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3028 EEPROM which holds the environment, is reached over
3029 a pca9547 i2c mux with address 0x70, channel 3.
3031 - CONFIG_ENV_IS_IN_DATAFLASH:
3033 Define this if you have a DataFlash memory device which you
3034 want to use for the environment.
3036 - CONFIG_ENV_OFFSET:
3040 These three #defines specify the offset and size of the
3041 environment area within the total memory of your DataFlash placed
3042 at the specified address.
3044 - CONFIG_ENV_IS_IN_REMOTE:
3046 Define this if you have a remote memory space which you
3047 want to use for the local device's environment.
3052 These two #defines specify the address and size of the
3053 environment area within the remote memory space. The
3054 local device can get the environment from remote memory
3055 space by SRIO or other links.
3057 BE CAREFUL! For some special cases, the local device can not use
3058 "saveenv" command. For example, the local device will get the
3059 environment stored in a remote NOR flash by SRIO link, but it can
3060 not erase, write this NOR flash by SRIO interface.
3062 - CONFIG_ENV_IS_IN_NAND:
3064 Define this if you have a NAND device which you want to use
3065 for the environment.
3067 - CONFIG_ENV_OFFSET:
3070 These two #defines specify the offset and size of the environment
3071 area within the first NAND device. CONFIG_ENV_OFFSET must be
3072 aligned to an erase block boundary.
3074 - CONFIG_ENV_OFFSET_REDUND (optional):
3076 This setting describes a second storage area of CONFIG_ENV_SIZE
3077 size used to hold a redundant copy of the environment data, so
3078 that there is a valid backup copy in case there is a power failure
3079 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3080 aligned to an erase block boundary.
3082 - CONFIG_ENV_RANGE (optional):
3084 Specifies the length of the region in which the environment
3085 can be written. This should be a multiple of the NAND device's
3086 block size. Specifying a range with more erase blocks than
3087 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3088 the range to be avoided.
3090 - CONFIG_ENV_OFFSET_OOB (optional):
3092 Enables support for dynamically retrieving the offset of the
3093 environment from block zero's out-of-band data. The
3094 "nand env.oob" command can be used to record this offset.
3095 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3096 using CONFIG_ENV_OFFSET_OOB.
3098 - CONFIG_NAND_ENV_DST
3100 Defines address in RAM to which the nand_spl code should copy the
3101 environment. If redundant environment is used, it will be copied to
3102 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3104 - CONFIG_SYS_SPI_INIT_OFFSET
3106 Defines offset to the initial SPI buffer area in DPRAM. The
3107 area is used at an early stage (ROM part) if the environment
3108 is configured to reside in the SPI EEPROM: We need a 520 byte
3109 scratch DPRAM area. It is used between the two initialization
3110 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3111 to be a good choice since it makes it far enough from the
3112 start of the data area as well as from the stack pointer.
3114 Please note that the environment is read-only until the monitor
3115 has been relocated to RAM and a RAM copy of the environment has been
3116 created; also, when using EEPROM you will have to use getenv_f()
3117 until then to read environment variables.
3119 The environment is protected by a CRC32 checksum. Before the monitor
3120 is relocated into RAM, as a result of a bad CRC you will be working
3121 with the compiled-in default environment - *silently*!!! [This is
3122 necessary, because the first environment variable we need is the
3123 "baudrate" setting for the console - if we have a bad CRC, we don't
3124 have any device yet where we could complain.]
3126 Note: once the monitor has been relocated, then it will complain if
3127 the default environment is used; a new CRC is computed as soon as you
3128 use the "saveenv" command to store a valid environment.
3130 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3131 Echo the inverted Ethernet link state to the fault LED.
3133 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3134 also needs to be defined.
3136 - CONFIG_SYS_FAULT_MII_ADDR:
3137 MII address of the PHY to check for the Ethernet link state.
3139 - CONFIG_NS16550_MIN_FUNCTIONS:
3140 Define this if you desire to only have use of the NS16550_init
3141 and NS16550_putc functions for the serial driver located at
3142 drivers/serial/ns16550.c. This option is useful for saving
3143 space for already greatly restricted images, including but not
3144 limited to NAND_SPL configurations.
3146 Low Level (hardware related) configuration options:
3147 ---------------------------------------------------
3149 - CONFIG_SYS_CACHELINE_SIZE:
3150 Cache Line Size of the CPU.
3152 - CONFIG_SYS_DEFAULT_IMMR:
3153 Default address of the IMMR after system reset.
3155 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3156 and RPXsuper) to be able to adjust the position of
3157 the IMMR register after a reset.
3159 - CONFIG_SYS_CCSRBAR_DEFAULT:
3160 Default (power-on reset) physical address of CCSR on Freescale
3163 - CONFIG_SYS_CCSRBAR:
3164 Virtual address of CCSR. On a 32-bit build, this is typically
3165 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3167 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3168 for cross-platform code that uses that macro instead.
3170 - CONFIG_SYS_CCSRBAR_PHYS:
3171 Physical address of CCSR. CCSR can be relocated to a new
3172 physical address, if desired. In this case, this macro should
3173 be set to that address. Otherwise, it should be set to the
3174 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3175 is typically relocated on 36-bit builds. It is recommended
3176 that this macro be defined via the _HIGH and _LOW macros:
3178 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3179 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3181 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3182 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3183 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3184 used in assembly code, so it must not contain typecasts or
3185 integer size suffixes (e.g. "ULL").
3187 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3188 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3189 used in assembly code, so it must not contain typecasts or
3190 integer size suffixes (e.g. "ULL").
3192 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3193 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3194 forced to a value that ensures that CCSR is not relocated.
3196 - Floppy Disk Support:
3197 CONFIG_SYS_FDC_DRIVE_NUMBER
3199 the default drive number (default value 0)
3201 CONFIG_SYS_ISA_IO_STRIDE
3203 defines the spacing between FDC chipset registers
3206 CONFIG_SYS_ISA_IO_OFFSET
3208 defines the offset of register from address. It
3209 depends on which part of the data bus is connected to
3210 the FDC chipset. (default value 0)
3212 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3213 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3216 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3217 fdc_hw_init() is called at the beginning of the FDC
3218 setup. fdc_hw_init() must be provided by the board
3219 source code. It is used to make hardware dependant
3223 Most IDE controllers were designed to be connected with PCI
3224 interface. Only few of them were designed for AHB interface.
3225 When software is doing ATA command and data transfer to
3226 IDE devices through IDE-AHB controller, some additional
3227 registers accessing to these kind of IDE-AHB controller
3230 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3231 DO NOT CHANGE unless you know exactly what you're
3232 doing! (11-4) [MPC8xx/82xx systems only]
3234 - CONFIG_SYS_INIT_RAM_ADDR:
3236 Start address of memory area that can be used for
3237 initial data and stack; please note that this must be
3238 writable memory that is working WITHOUT special
3239 initialization, i. e. you CANNOT use normal RAM which
3240 will become available only after programming the
3241 memory controller and running certain initialization
3244 U-Boot uses the following memory types:
3245 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3246 - MPC824X: data cache
3247 - PPC4xx: data cache
3249 - CONFIG_SYS_GBL_DATA_OFFSET:
3251 Offset of the initial data structure in the memory
3252 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3253 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3254 data is located at the end of the available space
3255 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3256 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3257 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3258 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3261 On the MPC824X (or other systems that use the data
3262 cache for initial memory) the address chosen for
3263 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3264 point to an otherwise UNUSED address space between
3265 the top of RAM and the start of the PCI space.
3267 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3269 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3271 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3273 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3275 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3277 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3279 - CONFIG_SYS_OR_TIMING_SDRAM:
3282 - CONFIG_SYS_MAMR_PTA:
3283 periodic timer for refresh
3285 - CONFIG_SYS_DER: Debug Event Register (37-47)
3287 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3288 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3289 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3290 CONFIG_SYS_BR1_PRELIM:
3291 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3293 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3294 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3295 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3296 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3298 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3299 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3300 Machine Mode Register and Memory Periodic Timer
3301 Prescaler definitions (SDRAM timing)
3303 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3304 enable I2C microcode relocation patch (MPC8xx);
3305 define relocation offset in DPRAM [DSP2]
3307 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3308 enable SMC microcode relocation patch (MPC8xx);
3309 define relocation offset in DPRAM [SMC1]
3311 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3312 enable SPI microcode relocation patch (MPC8xx);
3313 define relocation offset in DPRAM [SCC4]
3315 - CONFIG_SYS_USE_OSCCLK:
3316 Use OSCM clock mode on MBX8xx board. Be careful,
3317 wrong setting might damage your board. Read
3318 doc/README.MBX before setting this variable!
3320 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3321 Offset of the bootmode word in DPRAM used by post
3322 (Power On Self Tests). This definition overrides
3323 #define'd default value in commproc.h resp.
3326 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3327 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3328 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3329 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3330 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3331 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3332 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3333 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3334 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3336 - CONFIG_PCI_DISABLE_PCIE:
3337 Disable PCI-Express on systems where it is supported but not
3341 Chip has SRIO or not
3344 Board has SRIO 1 port available
3347 Board has SRIO 2 port available
3349 - CONFIG_SYS_SRIOn_MEM_VIRT:
3350 Virtual Address of SRIO port 'n' memory region
3352 - CONFIG_SYS_SRIOn_MEM_PHYS:
3353 Physical Address of SRIO port 'n' memory region
3355 - CONFIG_SYS_SRIOn_MEM_SIZE:
3356 Size of SRIO port 'n' memory region
3358 - CONFIG_SYS_NDFC_16
3359 Defined to tell the NDFC that the NAND chip is using a
3362 - CONFIG_SYS_NDFC_EBC0_CFG
3363 Sets the EBC0_CFG register for the NDFC. If not defined
3364 a default value will be used.
3367 Get DDR timing information from an I2C EEPROM. Common
3368 with pluggable memory modules such as SODIMMs
3371 I2C address of the SPD EEPROM
3373 - CONFIG_SYS_SPD_BUS_NUM
3374 If SPD EEPROM is on an I2C bus other than the first
3375 one, specify here. Note that the value must resolve
3376 to something your driver can deal with.
3378 - CONFIG_SYS_DDR_RAW_TIMING
3379 Get DDR timing information from other than SPD. Common with
3380 soldered DDR chips onboard without SPD. DDR raw timing
3381 parameters are extracted from datasheet and hard-coded into
3382 header files or board specific files.
3384 - CONFIG_FSL_DDR_INTERACTIVE
3385 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3387 - CONFIG_SYS_83XX_DDR_USES_CS0
3388 Only for 83xx systems. If specified, then DDR should
3389 be configured using CS0 and CS1 instead of CS2 and CS3.
3391 - CONFIG_ETHER_ON_FEC[12]
3392 Define to enable FEC[12] on a 8xx series processor.
3394 - CONFIG_FEC[12]_PHY
3395 Define to the hardcoded PHY address which corresponds
3396 to the given FEC; i. e.
3397 #define CONFIG_FEC1_PHY 4
3398 means that the PHY with address 4 is connected to FEC1
3400 When set to -1, means to probe for first available.
3402 - CONFIG_FEC[12]_PHY_NORXERR
3403 The PHY does not have a RXERR line (RMII only).
3404 (so program the FEC to ignore it).
3407 Enable RMII mode for all FECs.
3408 Note that this is a global option, we can't
3409 have one FEC in standard MII mode and another in RMII mode.
3411 - CONFIG_CRC32_VERIFY
3412 Add a verify option to the crc32 command.
3415 => crc32 -v <address> <count> <crc32>
3417 Where address/count indicate a memory area
3418 and crc32 is the correct crc32 which the
3422 Add the "loopw" memory command. This only takes effect if
3423 the memory commands are activated globally (CONFIG_CMD_MEM).
3426 Add the "mdc" and "mwc" memory commands. These are cyclic
3431 This command will print 4 bytes (10,11,12,13) each 500 ms.
3433 => mwc.l 100 12345678 10
3434 This command will write 12345678 to address 100 all 10 ms.
3436 This only takes effect if the memory commands are activated
3437 globally (CONFIG_CMD_MEM).
3439 - CONFIG_SKIP_LOWLEVEL_INIT
3440 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3441 low level initializations (like setting up the memory
3442 controller) are omitted and/or U-Boot does not
3443 relocate itself into RAM.
3445 Normally this variable MUST NOT be defined. The only
3446 exception is when U-Boot is loaded (to RAM) by some
3447 other boot loader or by a debugger which performs
3448 these initializations itself.
3451 Modifies the behaviour of start.S when compiling a loader
3452 that is executed before the actual U-Boot. E.g. when
3453 compiling a NAND SPL.
3455 - CONFIG_USE_ARCH_MEMCPY
3456 CONFIG_USE_ARCH_MEMSET
3457 If these options are used a optimized version of memcpy/memset will
3458 be used if available. These functions may be faster under some
3459 conditions but may increase the binary size.
3461 Freescale QE/FMAN Firmware Support:
3462 -----------------------------------
3464 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3465 loading of "firmware", which is encoded in the QE firmware binary format.
3466 This firmware often needs to be loaded during U-Boot booting, so macros
3467 are used to identify the storage device (NOR flash, SPI, etc) and the address
3470 - CONFIG_SYS_QE_FMAN_FW_ADDR
3471 The address in the storage device where the firmware is located. The
3472 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3475 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3476 The maximum possible size of the firmware. The firmware binary format
3477 has a field that specifies the actual size of the firmware, but it
3478 might not be possible to read any part of the firmware unless some
3479 local storage is allocated to hold the entire firmware first.
3481 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3482 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3483 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3484 virtual address in NOR flash.
3486 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3487 Specifies that QE/FMAN firmware is located in NAND flash.
3488 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3490 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3491 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3492 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3494 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3495 Specifies that QE/FMAN firmware is located on the primary SPI
3496 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3498 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3499 Specifies that QE/FMAN firmware is located in the remote (master)
3500 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3501 can be mapped from slave TLB->slave LAW->slave SRIO outbound window
3502 ->master inbound window->master LAW->the ucode address in master's
3505 Building the Software:
3506 ======================
3508 Building U-Boot has been tested in several native build environments
3509 and in many different cross environments. Of course we cannot support
3510 all possibly existing versions of cross development tools in all
3511 (potentially obsolete) versions. In case of tool chain problems we
3512 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3513 which is extensively used to build and test U-Boot.
3515 If you are not using a native environment, it is assumed that you
3516 have GNU cross compiling tools available in your path. In this case,
3517 you must set the environment variable CROSS_COMPILE in your shell.
3518 Note that no changes to the Makefile or any other source files are
3519 necessary. For example using the ELDK on a 4xx CPU, please enter:
3521 $ CROSS_COMPILE=ppc_4xx-
3522 $ export CROSS_COMPILE
3524 Note: If you wish to generate Windows versions of the utilities in
3525 the tools directory you can use the MinGW toolchain
3526 (http://www.mingw.org). Set your HOST tools to the MinGW
3527 toolchain and execute 'make tools'. For example:
3529 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3531 Binaries such as tools/mkimage.exe will be created which can
3532 be executed on computers running Windows.
3534 U-Boot is intended to be simple to build. After installing the
3535 sources you must configure U-Boot for one specific board type. This
3540 where "NAME_config" is the name of one of the existing configu-
3541 rations; see boards.cfg for supported names.
3543 Note: for some board special configuration names may exist; check if
3544 additional information is available from the board vendor; for
3545 instance, the TQM823L systems are available without (standard)
3546 or with LCD support. You can select such additional "features"
3547 when choosing the configuration, i. e.
3550 - will configure for a plain TQM823L, i. e. no LCD support
3552 make TQM823L_LCD_config
3553 - will configure for a TQM823L with U-Boot console on LCD
3558 Finally, type "make all", and you should get some working U-Boot
3559 images ready for download to / installation on your system:
3561 - "u-boot.bin" is a raw binary image
3562 - "u-boot" is an image in ELF binary format
3563 - "u-boot.srec" is in Motorola S-Record format
3565 By default the build is performed locally and the objects are saved
3566 in the source directory. One of the two methods can be used to change
3567 this behavior and build U-Boot to some external directory:
3569 1. Add O= to the make command line invocations:
3571 make O=/tmp/build distclean
3572 make O=/tmp/build NAME_config
3573 make O=/tmp/build all
3575 2. Set environment variable BUILD_DIR to point to the desired location:
3577 export BUILD_DIR=/tmp/build
3582 Note that the command line "O=" setting overrides the BUILD_DIR environment
3586 Please be aware that the Makefiles assume you are using GNU make, so
3587 for instance on NetBSD you might need to use "gmake" instead of
3591 If the system board that you have is not listed, then you will need
3592 to port U-Boot to your hardware platform. To do this, follow these
3595 1. Add a new configuration option for your board to the toplevel
3596 "boards.cfg" file, using the existing entries as examples.
3597 Follow the instructions there to keep the boards in order.
3598 2. Create a new directory to hold your board specific code. Add any
3599 files you need. In your board directory, you will need at least
3600 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3601 3. Create a new configuration file "include/configs/<board>.h" for
3603 3. If you're porting U-Boot to a new CPU, then also create a new
3604 directory to hold your CPU specific code. Add any files you need.
3605 4. Run "make <board>_config" with your new name.
3606 5. Type "make", and you should get a working "u-boot.srec" file
3607 to be installed on your target system.
3608 6. Debug and solve any problems that might arise.
3609 [Of course, this last step is much harder than it sounds.]
3612 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3613 ==============================================================
3615 If you have modified U-Boot sources (for instance added a new board
3616 or support for new devices, a new CPU, etc.) you are expected to
3617 provide feedback to the other developers. The feedback normally takes
3618 the form of a "patch", i. e. a context diff against a certain (latest
3619 official or latest in the git repository) version of U-Boot sources.
3621 But before you submit such a patch, please verify that your modifi-
3622 cation did not break existing code. At least make sure that *ALL* of
3623 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3624 just run the "MAKEALL" script, which will configure and build U-Boot
3625 for ALL supported system. Be warned, this will take a while. You can
3626 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3627 environment variable to the script, i. e. to use the ELDK cross tools
3630 CROSS_COMPILE=ppc_8xx- MAKEALL
3632 or to build on a native PowerPC system you can type
3634 CROSS_COMPILE=' ' MAKEALL
3636 When using the MAKEALL script, the default behaviour is to build
3637 U-Boot in the source directory. This location can be changed by
3638 setting the BUILD_DIR environment variable. Also, for each target
3639 built, the MAKEALL script saves two log files (<target>.ERR and
3640 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3641 location can be changed by setting the MAKEALL_LOGDIR environment
3642 variable. For example:
3644 export BUILD_DIR=/tmp/build
3645 export MAKEALL_LOGDIR=/tmp/log
3646 CROSS_COMPILE=ppc_8xx- MAKEALL
3648 With the above settings build objects are saved in the /tmp/build,
3649 log files are saved in the /tmp/log and the source tree remains clean
3650 during the whole build process.
3653 See also "U-Boot Porting Guide" below.
3656 Monitor Commands - Overview:
3657 ============================
3659 go - start application at address 'addr'
3660 run - run commands in an environment variable
3661 bootm - boot application image from memory
3662 bootp - boot image via network using BootP/TFTP protocol
3663 bootz - boot zImage from memory
3664 tftpboot- boot image via network using TFTP protocol
3665 and env variables "ipaddr" and "serverip"
3666 (and eventually "gatewayip")
3667 tftpput - upload a file via network using TFTP protocol
3668 rarpboot- boot image via network using RARP/TFTP protocol
3669 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3670 loads - load S-Record file over serial line
3671 loadb - load binary file over serial line (kermit mode)
3673 mm - memory modify (auto-incrementing)
3674 nm - memory modify (constant address)
3675 mw - memory write (fill)
3677 cmp - memory compare
3678 crc32 - checksum calculation
3679 i2c - I2C sub-system
3680 sspi - SPI utility commands
3681 base - print or set address offset
3682 printenv- print environment variables
3683 setenv - set environment variables
3684 saveenv - save environment variables to persistent storage
3685 protect - enable or disable FLASH write protection
3686 erase - erase FLASH memory
3687 flinfo - print FLASH memory information
3688 bdinfo - print Board Info structure
3689 iminfo - print header information for application image
3690 coninfo - print console devices and informations
3691 ide - IDE sub-system
3692 loop - infinite loop on address range
3693 loopw - infinite write loop on address range
3694 mtest - simple RAM test
3695 icache - enable or disable instruction cache
3696 dcache - enable or disable data cache
3697 reset - Perform RESET of the CPU
3698 echo - echo args to console
3699 version - print monitor version
3700 help - print online help
3701 ? - alias for 'help'
3704 Monitor Commands - Detailed Description:
3705 ========================================
3709 For now: just type "help <command>".
3712 Environment Variables:
3713 ======================
3715 U-Boot supports user configuration using Environment Variables which
3716 can be made persistent by saving to Flash memory.
3718 Environment Variables are set using "setenv", printed using
3719 "printenv", and saved to Flash using "saveenv". Using "setenv"
3720 without a value can be used to delete a variable from the
3721 environment. As long as you don't save the environment you are
3722 working with an in-memory copy. In case the Flash area containing the
3723 environment is erased by accident, a default environment is provided.
3725 Some configuration options can be set using Environment Variables.
3727 List of environment variables (most likely not complete):
3729 baudrate - see CONFIG_BAUDRATE
3731 bootdelay - see CONFIG_BOOTDELAY
3733 bootcmd - see CONFIG_BOOTCOMMAND
3735 bootargs - Boot arguments when booting an RTOS image
3737 bootfile - Name of the image to load with TFTP
3739 bootm_low - Memory range available for image processing in the bootm
3740 command can be restricted. This variable is given as
3741 a hexadecimal number and defines lowest address allowed
3742 for use by the bootm command. See also "bootm_size"
3743 environment variable. Address defined by "bootm_low" is
3744 also the base of the initial memory mapping for the Linux
3745 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3748 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3749 This variable is given as a hexadecimal number and it
3750 defines the size of the memory region starting at base
3751 address bootm_low that is accessible by the Linux kernel
3752 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3753 as the default value if it is defined, and bootm_size is
3756 bootm_size - Memory range available for image processing in the bootm
3757 command can be restricted. This variable is given as
3758 a hexadecimal number and defines the size of the region
3759 allowed for use by the bootm command. See also "bootm_low"
3760 environment variable.
3762 updatefile - Location of the software update file on a TFTP server, used
3763 by the automatic software update feature. Please refer to
3764 documentation in doc/README.update for more details.
3766 autoload - if set to "no" (any string beginning with 'n'),
3767 "bootp" will just load perform a lookup of the
3768 configuration from the BOOTP server, but not try to
3769 load any image using TFTP
3771 autostart - if set to "yes", an image loaded using the "bootp",
3772 "rarpboot", "tftpboot" or "diskboot" commands will
3773 be automatically started (by internally calling
3776 If set to "no", a standalone image passed to the
3777 "bootm" command will be copied to the load address
3778 (and eventually uncompressed), but NOT be started.
3779 This can be used to load and uncompress arbitrary
3782 fdt_high - if set this restricts the maximum address that the
3783 flattened device tree will be copied into upon boot.
3784 For example, if you have a system with 1 GB memory
3785 at physical address 0x10000000, while Linux kernel
3786 only recognizes the first 704 MB as low memory, you
3787 may need to set fdt_high as 0x3C000000 to have the
3788 device tree blob be copied to the maximum address
3789 of the 704 MB low memory, so that Linux kernel can
3790 access it during the boot procedure.
3792 If this is set to the special value 0xFFFFFFFF then
3793 the fdt will not be copied at all on boot. For this
3794 to work it must reside in writable memory, have
3795 sufficient padding on the end of it for u-boot to
3796 add the information it needs into it, and the memory
3797 must be accessible by the kernel.
3799 fdtcontroladdr- if set this is the address of the control flattened
3800 device tree used by U-Boot when CONFIG_OF_CONTROL is
3803 i2cfast - (PPC405GP|PPC405EP only)
3804 if set to 'y' configures Linux I2C driver for fast
3805 mode (400kHZ). This environment variable is used in
3806 initialization code. So, for changes to be effective
3807 it must be saved and board must be reset.
3809 initrd_high - restrict positioning of initrd images:
3810 If this variable is not set, initrd images will be
3811 copied to the highest possible address in RAM; this
3812 is usually what you want since it allows for
3813 maximum initrd size. If for some reason you want to
3814 make sure that the initrd image is loaded below the
3815 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3816 variable to a value of "no" or "off" or "0".
3817 Alternatively, you can set it to a maximum upper
3818 address to use (U-Boot will still check that it
3819 does not overwrite the U-Boot stack and data).
3821 For instance, when you have a system with 16 MB
3822 RAM, and want to reserve 4 MB from use by Linux,
3823 you can do this by adding "mem=12M" to the value of
3824 the "bootargs" variable. However, now you must make
3825 sure that the initrd image is placed in the first
3826 12 MB as well - this can be done with
3828 setenv initrd_high 00c00000
3830 If you set initrd_high to 0xFFFFFFFF, this is an
3831 indication to U-Boot that all addresses are legal
3832 for the Linux kernel, including addresses in flash
3833 memory. In this case U-Boot will NOT COPY the
3834 ramdisk at all. This may be useful to reduce the
3835 boot time on your system, but requires that this
3836 feature is supported by your Linux kernel.
3838 ipaddr - IP address; needed for tftpboot command
3840 loadaddr - Default load address for commands like "bootp",
3841 "rarpboot", "tftpboot", "loadb" or "diskboot"
3843 loads_echo - see CONFIG_LOADS_ECHO
3845 serverip - TFTP server IP address; needed for tftpboot command
3847 bootretry - see CONFIG_BOOT_RETRY_TIME
3849 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3851 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3853 ethprime - controls which interface is used first.
3855 ethact - controls which interface is currently active.
3856 For example you can do the following
3858 => setenv ethact FEC
3859 => ping 192.168.0.1 # traffic sent on FEC
3860 => setenv ethact SCC
3861 => ping 10.0.0.1 # traffic sent on SCC
3863 ethrotate - When set to "no" U-Boot does not go through all
3864 available network interfaces.
3865 It just stays at the currently selected interface.
3867 netretry - When set to "no" each network operation will
3868 either succeed or fail without retrying.
3869 When set to "once" the network operation will
3870 fail when all the available network interfaces
3871 are tried once without success.
3872 Useful on scripts which control the retry operation
3875 npe_ucode - set load address for the NPE microcode
3877 tftpsrcport - If this is set, the value is used for TFTP's
3880 tftpdstport - If this is set, the value is used for TFTP's UDP
3881 destination port instead of the Well Know Port 69.
3883 tftpblocksize - Block size to use for TFTP transfers; if not set,
3884 we use the TFTP server's default block size
3886 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3887 seconds, minimum value is 1000 = 1 second). Defines
3888 when a packet is considered to be lost so it has to
3889 be retransmitted. The default is 5000 = 5 seconds.
3890 Lowering this value may make downloads succeed
3891 faster in networks with high packet loss rates or
3892 with unreliable TFTP servers.
3894 vlan - When set to a value < 4095 the traffic over
3895 Ethernet is encapsulated/received over 802.1q
3898 The following image location variables contain the location of images
3899 used in booting. The "Image" column gives the role of the image and is
3900 not an environment variable name. The other columns are environment
3901 variable names. "File Name" gives the name of the file on a TFTP
3902 server, "RAM Address" gives the location in RAM the image will be
3903 loaded to, and "Flash Location" gives the image's address in NOR
3904 flash or offset in NAND flash.
3906 *Note* - these variables don't have to be defined for all boards, some
3907 boards currenlty use other variables for these purposes, and some
3908 boards use these variables for other purposes.
3910 Image File Name RAM Address Flash Location
3911 ----- --------- ----------- --------------
3912 u-boot u-boot u-boot_addr_r u-boot_addr
3913 Linux kernel bootfile kernel_addr_r kernel_addr
3914 device tree blob fdtfile fdt_addr_r fdt_addr
3915 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3917 The following environment variables may be used and automatically
3918 updated by the network boot commands ("bootp" and "rarpboot"),
3919 depending the information provided by your boot server:
3921 bootfile - see above
3922 dnsip - IP address of your Domain Name Server
3923 dnsip2 - IP address of your secondary Domain Name Server
3924 gatewayip - IP address of the Gateway (Router) to use
3925 hostname - Target hostname
3927 netmask - Subnet Mask
3928 rootpath - Pathname of the root filesystem on the NFS server
3929 serverip - see above
3932 There are two special Environment Variables:
3934 serial# - contains hardware identification information such
3935 as type string and/or serial number
3936 ethaddr - Ethernet address
3938 These variables can be set only once (usually during manufacturing of
3939 the board). U-Boot refuses to delete or overwrite these variables
3940 once they have been set once.
3943 Further special Environment Variables:
3945 ver - Contains the U-Boot version string as printed
3946 with the "version" command. This variable is
3947 readonly (see CONFIG_VERSION_VARIABLE).
3950 Please note that changes to some configuration parameters may take
3951 only effect after the next boot (yes, that's just like Windoze :-).
3954 Command Line Parsing:
3955 =====================
3957 There are two different command line parsers available with U-Boot:
3958 the old "simple" one, and the much more powerful "hush" shell:
3960 Old, simple command line parser:
3961 --------------------------------
3963 - supports environment variables (through setenv / saveenv commands)
3964 - several commands on one line, separated by ';'
3965 - variable substitution using "... ${name} ..." syntax
3966 - special characters ('$', ';') can be escaped by prefixing with '\',
3968 setenv bootcmd bootm \${address}
3969 - You can also escape text by enclosing in single apostrophes, for example:
3970 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3975 - similar to Bourne shell, with control structures like
3976 if...then...else...fi, for...do...done; while...do...done,
3977 until...do...done, ...
3978 - supports environment ("global") variables (through setenv / saveenv
3979 commands) and local shell variables (through standard shell syntax
3980 "name=value"); only environment variables can be used with "run"
3986 (1) If a command line (or an environment variable executed by a "run"
3987 command) contains several commands separated by semicolon, and
3988 one of these commands fails, then the remaining commands will be
3991 (2) If you execute several variables with one call to run (i. e.
3992 calling run with a list of variables as arguments), any failing
3993 command will cause "run" to terminate, i. e. the remaining
3994 variables are not executed.
3996 Note for Redundant Ethernet Interfaces:
3997 =======================================
3999 Some boards come with redundant Ethernet interfaces; U-Boot supports
4000 such configurations and is capable of automatic selection of a
4001 "working" interface when needed. MAC assignment works as follows:
4003 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4004 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4005 "eth1addr" (=>eth1), "eth2addr", ...
4007 If the network interface stores some valid MAC address (for instance
4008 in SROM), this is used as default address if there is NO correspon-
4009 ding setting in the environment; if the corresponding environment
4010 variable is set, this overrides the settings in the card; that means:
4012 o If the SROM has a valid MAC address, and there is no address in the
4013 environment, the SROM's address is used.
4015 o If there is no valid address in the SROM, and a definition in the
4016 environment exists, then the value from the environment variable is
4019 o If both the SROM and the environment contain a MAC address, and
4020 both addresses are the same, this MAC address is used.
4022 o If both the SROM and the environment contain a MAC address, and the
4023 addresses differ, the value from the environment is used and a
4026 o If neither SROM nor the environment contain a MAC address, an error
4029 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4030 will be programmed into hardware as part of the initialization process. This
4031 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4032 The naming convention is as follows:
4033 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4038 U-Boot is capable of booting (and performing other auxiliary operations on)
4039 images in two formats:
4041 New uImage format (FIT)
4042 -----------------------
4044 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4045 to Flattened Device Tree). It allows the use of images with multiple
4046 components (several kernels, ramdisks, etc.), with contents protected by
4047 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4053 Old image format is based on binary files which can be basically anything,
4054 preceded by a special header; see the definitions in include/image.h for
4055 details; basically, the header defines the following image properties:
4057 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4058 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4059 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4060 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4062 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4063 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4064 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4065 * Compression Type (uncompressed, gzip, bzip2)
4071 The header is marked by a special Magic Number, and both the header
4072 and the data portions of the image are secured against corruption by
4079 Although U-Boot should support any OS or standalone application
4080 easily, the main focus has always been on Linux during the design of
4083 U-Boot includes many features that so far have been part of some
4084 special "boot loader" code within the Linux kernel. Also, any
4085 "initrd" images to be used are no longer part of one big Linux image;
4086 instead, kernel and "initrd" are separate images. This implementation
4087 serves several purposes:
4089 - the same features can be used for other OS or standalone
4090 applications (for instance: using compressed images to reduce the
4091 Flash memory footprint)
4093 - it becomes much easier to port new Linux kernel versions because
4094 lots of low-level, hardware dependent stuff are done by U-Boot
4096 - the same Linux kernel image can now be used with different "initrd"
4097 images; of course this also means that different kernel images can
4098 be run with the same "initrd". This makes testing easier (you don't
4099 have to build a new "zImage.initrd" Linux image when you just
4100 change a file in your "initrd"). Also, a field-upgrade of the
4101 software is easier now.
4107 Porting Linux to U-Boot based systems:
4108 ---------------------------------------
4110 U-Boot cannot save you from doing all the necessary modifications to
4111 configure the Linux device drivers for use with your target hardware
4112 (no, we don't intend to provide a full virtual machine interface to
4115 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4117 Just make sure your machine specific header file (for instance
4118 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4119 Information structure as we define in include/asm-<arch>/u-boot.h,
4120 and make sure that your definition of IMAP_ADDR uses the same value
4121 as your U-Boot configuration in CONFIG_SYS_IMMR.
4124 Configuring the Linux kernel:
4125 -----------------------------
4127 No specific requirements for U-Boot. Make sure you have some root
4128 device (initial ramdisk, NFS) for your target system.
4131 Building a Linux Image:
4132 -----------------------
4134 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4135 not used. If you use recent kernel source, a new build target
4136 "uImage" will exist which automatically builds an image usable by
4137 U-Boot. Most older kernels also have support for a "pImage" target,
4138 which was introduced for our predecessor project PPCBoot and uses a
4139 100% compatible format.
4148 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4149 encapsulate a compressed Linux kernel image with header information,
4150 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4152 * build a standard "vmlinux" kernel image (in ELF binary format):
4154 * convert the kernel into a raw binary image:
4156 ${CROSS_COMPILE}-objcopy -O binary \
4157 -R .note -R .comment \
4158 -S vmlinux linux.bin
4160 * compress the binary image:
4164 * package compressed binary image for U-Boot:
4166 mkimage -A ppc -O linux -T kernel -C gzip \
4167 -a 0 -e 0 -n "Linux Kernel Image" \
4168 -d linux.bin.gz uImage
4171 The "mkimage" tool can also be used to create ramdisk images for use
4172 with U-Boot, either separated from the Linux kernel image, or
4173 combined into one file. "mkimage" encapsulates the images with a 64
4174 byte header containing information about target architecture,
4175 operating system, image type, compression method, entry points, time
4176 stamp, CRC32 checksums, etc.
4178 "mkimage" can be called in two ways: to verify existing images and
4179 print the header information, or to build new images.
4181 In the first form (with "-l" option) mkimage lists the information
4182 contained in the header of an existing U-Boot image; this includes
4183 checksum verification:
4185 tools/mkimage -l image
4186 -l ==> list image header information
4188 The second form (with "-d" option) is used to build a U-Boot image
4189 from a "data file" which is used as image payload:
4191 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4192 -n name -d data_file image
4193 -A ==> set architecture to 'arch'
4194 -O ==> set operating system to 'os'
4195 -T ==> set image type to 'type'
4196 -C ==> set compression type 'comp'
4197 -a ==> set load address to 'addr' (hex)
4198 -e ==> set entry point to 'ep' (hex)
4199 -n ==> set image name to 'name'
4200 -d ==> use image data from 'datafile'
4202 Right now, all Linux kernels for PowerPC systems use the same load
4203 address (0x00000000), but the entry point address depends on the
4206 - 2.2.x kernels have the entry point at 0x0000000C,
4207 - 2.3.x and later kernels have the entry point at 0x00000000.
4209 So a typical call to build a U-Boot image would read:
4211 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4212 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4213 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4214 > examples/uImage.TQM850L
4215 Image Name: 2.4.4 kernel for TQM850L
4216 Created: Wed Jul 19 02:34:59 2000
4217 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4218 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4219 Load Address: 0x00000000
4220 Entry Point: 0x00000000
4222 To verify the contents of the image (or check for corruption):
4224 -> tools/mkimage -l examples/uImage.TQM850L
4225 Image Name: 2.4.4 kernel for TQM850L
4226 Created: Wed Jul 19 02:34:59 2000
4227 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4228 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4229 Load Address: 0x00000000
4230 Entry Point: 0x00000000
4232 NOTE: for embedded systems where boot time is critical you can trade
4233 speed for memory and install an UNCOMPRESSED image instead: this
4234 needs more space in Flash, but boots much faster since it does not
4235 need to be uncompressed:
4237 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4238 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4239 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4240 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4241 > examples/uImage.TQM850L-uncompressed
4242 Image Name: 2.4.4 kernel for TQM850L
4243 Created: Wed Jul 19 02:34:59 2000
4244 Image Type: PowerPC Linux Kernel Image (uncompressed)
4245 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4246 Load Address: 0x00000000
4247 Entry Point: 0x00000000
4250 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4251 when your kernel is intended to use an initial ramdisk:
4253 -> tools/mkimage -n 'Simple Ramdisk Image' \
4254 > -A ppc -O linux -T ramdisk -C gzip \
4255 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4256 Image Name: Simple Ramdisk Image
4257 Created: Wed Jan 12 14:01:50 2000
4258 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4259 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4260 Load Address: 0x00000000
4261 Entry Point: 0x00000000
4264 Installing a Linux Image:
4265 -------------------------
4267 To downloading a U-Boot image over the serial (console) interface,
4268 you must convert the image to S-Record format:
4270 objcopy -I binary -O srec examples/image examples/image.srec
4272 The 'objcopy' does not understand the information in the U-Boot
4273 image header, so the resulting S-Record file will be relative to
4274 address 0x00000000. To load it to a given address, you need to
4275 specify the target address as 'offset' parameter with the 'loads'
4278 Example: install the image to address 0x40100000 (which on the
4279 TQM8xxL is in the first Flash bank):
4281 => erase 40100000 401FFFFF
4287 ## Ready for S-Record download ...
4288 ~>examples/image.srec
4289 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4291 15989 15990 15991 15992
4292 [file transfer complete]
4294 ## Start Addr = 0x00000000
4297 You can check the success of the download using the 'iminfo' command;
4298 this includes a checksum verification so you can be sure no data
4299 corruption happened:
4303 ## Checking Image at 40100000 ...
4304 Image Name: 2.2.13 for initrd on TQM850L
4305 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4306 Data Size: 335725 Bytes = 327 kB = 0 MB
4307 Load Address: 00000000
4308 Entry Point: 0000000c
4309 Verifying Checksum ... OK
4315 The "bootm" command is used to boot an application that is stored in
4316 memory (RAM or Flash). In case of a Linux kernel image, the contents
4317 of the "bootargs" environment variable is passed to the kernel as
4318 parameters. You can check and modify this variable using the
4319 "printenv" and "setenv" commands:
4322 => printenv bootargs
4323 bootargs=root=/dev/ram
4325 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4327 => printenv bootargs
4328 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4331 ## Booting Linux kernel at 40020000 ...
4332 Image Name: 2.2.13 for NFS on TQM850L
4333 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4334 Data Size: 381681 Bytes = 372 kB = 0 MB
4335 Load Address: 00000000
4336 Entry Point: 0000000c
4337 Verifying Checksum ... OK
4338 Uncompressing Kernel Image ... OK
4339 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
4340 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4341 time_init: decrementer frequency = 187500000/60
4342 Calibrating delay loop... 49.77 BogoMIPS
4343 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4346 If you want to boot a Linux kernel with initial RAM disk, you pass
4347 the memory addresses of both the kernel and the initrd image (PPBCOOT
4348 format!) to the "bootm" command:
4350 => imi 40100000 40200000
4352 ## Checking Image at 40100000 ...
4353 Image Name: 2.2.13 for initrd on TQM850L
4354 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4355 Data Size: 335725 Bytes = 327 kB = 0 MB
4356 Load Address: 00000000
4357 Entry Point: 0000000c
4358 Verifying Checksum ... OK
4360 ## Checking Image at 40200000 ...
4361 Image Name: Simple Ramdisk Image
4362 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4363 Data Size: 566530 Bytes = 553 kB = 0 MB
4364 Load Address: 00000000
4365 Entry Point: 00000000
4366 Verifying Checksum ... OK
4368 => bootm 40100000 40200000
4369 ## Booting Linux kernel at 40100000 ...
4370 Image Name: 2.2.13 for initrd on TQM850L
4371 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4372 Data Size: 335725 Bytes = 327 kB = 0 MB
4373 Load Address: 00000000
4374 Entry Point: 0000000c
4375 Verifying Checksum ... OK
4376 Uncompressing Kernel Image ... OK
4377 ## Loading RAMDisk Image at 40200000 ...
4378 Image Name: Simple Ramdisk Image
4379 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4380 Data Size: 566530 Bytes = 553 kB = 0 MB
4381 Load Address: 00000000
4382 Entry Point: 00000000
4383 Verifying Checksum ... OK
4384 Loading Ramdisk ... OK
4385 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
4386 Boot arguments: root=/dev/ram
4387 time_init: decrementer frequency = 187500000/60
4388 Calibrating delay loop... 49.77 BogoMIPS
4390 RAMDISK: Compressed image found at block 0
4391 VFS: Mounted root (ext2 filesystem).
4395 Boot Linux and pass a flat device tree:
4398 First, U-Boot must be compiled with the appropriate defines. See the section
4399 titled "Linux Kernel Interface" above for a more in depth explanation. The
4400 following is an example of how to start a kernel and pass an updated
4406 oft=oftrees/mpc8540ads.dtb
4407 => tftp $oftaddr $oft
4408 Speed: 1000, full duplex
4410 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4411 Filename 'oftrees/mpc8540ads.dtb'.
4412 Load address: 0x300000
4415 Bytes transferred = 4106 (100a hex)
4416 => tftp $loadaddr $bootfile
4417 Speed: 1000, full duplex
4419 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4421 Load address: 0x200000
4422 Loading:############
4424 Bytes transferred = 1029407 (fb51f hex)
4429 => bootm $loadaddr - $oftaddr
4430 ## Booting image at 00200000 ...
4431 Image Name: Linux-2.6.17-dirty
4432 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4433 Data Size: 1029343 Bytes = 1005.2 kB
4434 Load Address: 00000000
4435 Entry Point: 00000000
4436 Verifying Checksum ... OK
4437 Uncompressing Kernel Image ... OK
4438 Booting using flat device tree at 0x300000
4439 Using MPC85xx ADS machine description
4440 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4444 More About U-Boot Image Types:
4445 ------------------------------
4447 U-Boot supports the following image types:
4449 "Standalone Programs" are directly runnable in the environment
4450 provided by U-Boot; it is expected that (if they behave
4451 well) you can continue to work in U-Boot after return from
4452 the Standalone Program.
4453 "OS Kernel Images" are usually images of some Embedded OS which
4454 will take over control completely. Usually these programs
4455 will install their own set of exception handlers, device
4456 drivers, set up the MMU, etc. - this means, that you cannot
4457 expect to re-enter U-Boot except by resetting the CPU.
4458 "RAMDisk Images" are more or less just data blocks, and their
4459 parameters (address, size) are passed to an OS kernel that is
4461 "Multi-File Images" contain several images, typically an OS
4462 (Linux) kernel image and one or more data images like
4463 RAMDisks. This construct is useful for instance when you want
4464 to boot over the network using BOOTP etc., where the boot
4465 server provides just a single image file, but you want to get
4466 for instance an OS kernel and a RAMDisk image.
4468 "Multi-File Images" start with a list of image sizes, each
4469 image size (in bytes) specified by an "uint32_t" in network
4470 byte order. This list is terminated by an "(uint32_t)0".
4471 Immediately after the terminating 0 follow the images, one by
4472 one, all aligned on "uint32_t" boundaries (size rounded up to
4473 a multiple of 4 bytes).
4475 "Firmware Images" are binary images containing firmware (like
4476 U-Boot or FPGA images) which usually will be programmed to
4479 "Script files" are command sequences that will be executed by
4480 U-Boot's command interpreter; this feature is especially
4481 useful when you configure U-Boot to use a real shell (hush)
4482 as command interpreter.
4484 Booting the Linux zImage:
4485 -------------------------
4487 On some platforms, it's possible to boot Linux zImage. This is done
4488 using the "bootz" command. The syntax of "bootz" command is the same
4489 as the syntax of "bootm" command.
4491 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4492 kernel with raw initrd images. The syntax is slightly different, the
4493 address of the initrd must be augmented by it's size, in the following
4494 format: "<initrd addres>:<initrd size>".
4500 One of the features of U-Boot is that you can dynamically load and
4501 run "standalone" applications, which can use some resources of
4502 U-Boot like console I/O functions or interrupt services.
4504 Two simple examples are included with the sources:
4509 'examples/hello_world.c' contains a small "Hello World" Demo
4510 application; it is automatically compiled when you build U-Boot.
4511 It's configured to run at address 0x00040004, so you can play with it
4515 ## Ready for S-Record download ...
4516 ~>examples/hello_world.srec
4517 1 2 3 4 5 6 7 8 9 10 11 ...
4518 [file transfer complete]
4520 ## Start Addr = 0x00040004
4522 => go 40004 Hello World! This is a test.
4523 ## Starting application at 0x00040004 ...
4534 Hit any key to exit ...
4536 ## Application terminated, rc = 0x0
4538 Another example, which demonstrates how to register a CPM interrupt
4539 handler with the U-Boot code, can be found in 'examples/timer.c'.
4540 Here, a CPM timer is set up to generate an interrupt every second.
4541 The interrupt service routine is trivial, just printing a '.'
4542 character, but this is just a demo program. The application can be
4543 controlled by the following keys:
4545 ? - print current values og the CPM Timer registers
4546 b - enable interrupts and start timer
4547 e - stop timer and disable interrupts
4548 q - quit application
4551 ## Ready for S-Record download ...
4552 ~>examples/timer.srec
4553 1 2 3 4 5 6 7 8 9 10 11 ...
4554 [file transfer complete]
4556 ## Start Addr = 0x00040004
4559 ## Starting application at 0x00040004 ...
4562 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4565 [q, b, e, ?] Set interval 1000000 us
4568 [q, b, e, ?] ........
4569 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4572 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4575 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4578 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4580 [q, b, e, ?] ...Stopping timer
4582 [q, b, e, ?] ## Application terminated, rc = 0x0
4588 Over time, many people have reported problems when trying to use the
4589 "minicom" terminal emulation program for serial download. I (wd)
4590 consider minicom to be broken, and recommend not to use it. Under
4591 Unix, I recommend to use C-Kermit for general purpose use (and
4592 especially for kermit binary protocol download ("loadb" command), and
4593 use "cu" for S-Record download ("loads" command).
4595 Nevertheless, if you absolutely want to use it try adding this
4596 configuration to your "File transfer protocols" section:
4598 Name Program Name U/D FullScr IO-Red. Multi
4599 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4600 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4606 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4607 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4609 Building requires a cross environment; it is known to work on
4610 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4611 need gmake since the Makefiles are not compatible with BSD make).
4612 Note that the cross-powerpc package does not install include files;
4613 attempting to build U-Boot will fail because <machine/ansi.h> is
4614 missing. This file has to be installed and patched manually:
4616 # cd /usr/pkg/cross/powerpc-netbsd/include
4618 # ln -s powerpc machine
4619 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4620 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4622 Native builds *don't* work due to incompatibilities between native
4623 and U-Boot include files.
4625 Booting assumes that (the first part of) the image booted is a
4626 stage-2 loader which in turn loads and then invokes the kernel
4627 proper. Loader sources will eventually appear in the NetBSD source
4628 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4629 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4632 Implementation Internals:
4633 =========================
4635 The following is not intended to be a complete description of every
4636 implementation detail. However, it should help to understand the
4637 inner workings of U-Boot and make it easier to port it to custom
4641 Initial Stack, Global Data:
4642 ---------------------------
4644 The implementation of U-Boot is complicated by the fact that U-Boot
4645 starts running out of ROM (flash memory), usually without access to
4646 system RAM (because the memory controller is not initialized yet).
4647 This means that we don't have writable Data or BSS segments, and BSS
4648 is not initialized as zero. To be able to get a C environment working
4649 at all, we have to allocate at least a minimal stack. Implementation
4650 options for this are defined and restricted by the CPU used: Some CPU
4651 models provide on-chip memory (like the IMMR area on MPC8xx and
4652 MPC826x processors), on others (parts of) the data cache can be
4653 locked as (mis-) used as memory, etc.
4655 Chris Hallinan posted a good summary of these issues to the
4656 U-Boot mailing list:
4658 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4659 From: "Chris Hallinan" <clh@net1plus.com>
4660 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4663 Correct me if I'm wrong, folks, but the way I understand it
4664 is this: Using DCACHE as initial RAM for Stack, etc, does not
4665 require any physical RAM backing up the cache. The cleverness
4666 is that the cache is being used as a temporary supply of
4667 necessary storage before the SDRAM controller is setup. It's
4668 beyond the scope of this list to explain the details, but you
4669 can see how this works by studying the cache architecture and
4670 operation in the architecture and processor-specific manuals.
4672 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4673 is another option for the system designer to use as an
4674 initial stack/RAM area prior to SDRAM being available. Either
4675 option should work for you. Using CS 4 should be fine if your
4676 board designers haven't used it for something that would
4677 cause you grief during the initial boot! It is frequently not
4680 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4681 with your processor/board/system design. The default value
4682 you will find in any recent u-boot distribution in
4683 walnut.h should work for you. I'd set it to a value larger
4684 than your SDRAM module. If you have a 64MB SDRAM module, set
4685 it above 400_0000. Just make sure your board has no resources
4686 that are supposed to respond to that address! That code in
4687 start.S has been around a while and should work as is when
4688 you get the config right.
4693 It is essential to remember this, since it has some impact on the C
4694 code for the initialization procedures:
4696 * Initialized global data (data segment) is read-only. Do not attempt
4699 * Do not use any uninitialized global data (or implicitely initialized
4700 as zero data - BSS segment) at all - this is undefined, initiali-
4701 zation is performed later (when relocating to RAM).
4703 * Stack space is very limited. Avoid big data buffers or things like
4706 Having only the stack as writable memory limits means we cannot use
4707 normal global data to share information beween the code. But it
4708 turned out that the implementation of U-Boot can be greatly
4709 simplified by making a global data structure (gd_t) available to all
4710 functions. We could pass a pointer to this data as argument to _all_
4711 functions, but this would bloat the code. Instead we use a feature of
4712 the GCC compiler (Global Register Variables) to share the data: we
4713 place a pointer (gd) to the global data into a register which we
4714 reserve for this purpose.
4716 When choosing a register for such a purpose we are restricted by the
4717 relevant (E)ABI specifications for the current architecture, and by
4718 GCC's implementation.
4720 For PowerPC, the following registers have specific use:
4722 R2: reserved for system use
4723 R3-R4: parameter passing and return values
4724 R5-R10: parameter passing
4725 R13: small data area pointer
4729 (U-Boot also uses R12 as internal GOT pointer. r12
4730 is a volatile register so r12 needs to be reset when
4731 going back and forth between asm and C)
4733 ==> U-Boot will use R2 to hold a pointer to the global data
4735 Note: on PPC, we could use a static initializer (since the
4736 address of the global data structure is known at compile time),
4737 but it turned out that reserving a register results in somewhat
4738 smaller code - although the code savings are not that big (on
4739 average for all boards 752 bytes for the whole U-Boot image,
4740 624 text + 127 data).
4742 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4743 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4745 ==> U-Boot will use P3 to hold a pointer to the global data
4747 On ARM, the following registers are used:
4749 R0: function argument word/integer result
4750 R1-R3: function argument word
4752 R10: stack limit (used only if stack checking if enabled)
4753 R11: argument (frame) pointer
4754 R12: temporary workspace
4757 R15: program counter
4759 ==> U-Boot will use R8 to hold a pointer to the global data
4761 On Nios II, the ABI is documented here:
4762 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4764 ==> U-Boot will use gp to hold a pointer to the global data
4766 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4767 to access small data sections, so gp is free.
4769 On NDS32, the following registers are used:
4771 R0-R1: argument/return
4773 R15: temporary register for assembler
4774 R16: trampoline register
4775 R28: frame pointer (FP)
4776 R29: global pointer (GP)
4777 R30: link register (LP)
4778 R31: stack pointer (SP)
4779 PC: program counter (PC)
4781 ==> U-Boot will use R10 to hold a pointer to the global data
4783 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4784 or current versions of GCC may "optimize" the code too much.
4789 U-Boot runs in system state and uses physical addresses, i.e. the
4790 MMU is not used either for address mapping nor for memory protection.
4792 The available memory is mapped to fixed addresses using the memory
4793 controller. In this process, a contiguous block is formed for each
4794 memory type (Flash, SDRAM, SRAM), even when it consists of several
4795 physical memory banks.
4797 U-Boot is installed in the first 128 kB of the first Flash bank (on
4798 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4799 booting and sizing and initializing DRAM, the code relocates itself
4800 to the upper end of DRAM. Immediately below the U-Boot code some
4801 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4802 configuration setting]. Below that, a structure with global Board
4803 Info data is placed, followed by the stack (growing downward).
4805 Additionally, some exception handler code is copied to the low 8 kB
4806 of DRAM (0x00000000 ... 0x00001FFF).
4808 So a typical memory configuration with 16 MB of DRAM could look like
4811 0x0000 0000 Exception Vector code
4814 0x0000 2000 Free for Application Use
4820 0x00FB FF20 Monitor Stack (Growing downward)
4821 0x00FB FFAC Board Info Data and permanent copy of global data
4822 0x00FC 0000 Malloc Arena
4825 0x00FE 0000 RAM Copy of Monitor Code
4826 ... eventually: LCD or video framebuffer
4827 ... eventually: pRAM (Protected RAM - unchanged by reset)
4828 0x00FF FFFF [End of RAM]
4831 System Initialization:
4832 ----------------------
4834 In the reset configuration, U-Boot starts at the reset entry point
4835 (on most PowerPC systems at address 0x00000100). Because of the reset
4836 configuration for CS0# this is a mirror of the onboard Flash memory.
4837 To be able to re-map memory U-Boot then jumps to its link address.
4838 To be able to implement the initialization code in C, a (small!)
4839 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4840 which provide such a feature like MPC8xx or MPC8260), or in a locked
4841 part of the data cache. After that, U-Boot initializes the CPU core,
4842 the caches and the SIU.
4844 Next, all (potentially) available memory banks are mapped using a
4845 preliminary mapping. For example, we put them on 512 MB boundaries
4846 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4847 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4848 programmed for SDRAM access. Using the temporary configuration, a
4849 simple memory test is run that determines the size of the SDRAM
4852 When there is more than one SDRAM bank, and the banks are of
4853 different size, the largest is mapped first. For equal size, the first
4854 bank (CS2#) is mapped first. The first mapping is always for address
4855 0x00000000, with any additional banks following immediately to create
4856 contiguous memory starting from 0.
4858 Then, the monitor installs itself at the upper end of the SDRAM area
4859 and allocates memory for use by malloc() and for the global Board
4860 Info data; also, the exception vector code is copied to the low RAM
4861 pages, and the final stack is set up.
4863 Only after this relocation will you have a "normal" C environment;
4864 until that you are restricted in several ways, mostly because you are
4865 running from ROM, and because the code will have to be relocated to a
4869 U-Boot Porting Guide:
4870 ----------------------
4872 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4876 int main(int argc, char *argv[])
4878 sighandler_t no_more_time;
4880 signal(SIGALRM, no_more_time);
4881 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4883 if (available_money > available_manpower) {
4884 Pay consultant to port U-Boot;
4888 Download latest U-Boot source;
4890 Subscribe to u-boot mailing list;
4893 email("Hi, I am new to U-Boot, how do I get started?");
4896 Read the README file in the top level directory;
4897 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4898 Read applicable doc/*.README;
4899 Read the source, Luke;
4900 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4903 if (available_money > toLocalCurrency ($2500))
4906 Add a lot of aggravation and time;
4908 if (a similar board exists) { /* hopefully... */
4909 cp -a board/<similar> board/<myboard>
4910 cp include/configs/<similar>.h include/configs/<myboard>.h
4912 Create your own board support subdirectory;
4913 Create your own board include/configs/<myboard>.h file;
4915 Edit new board/<myboard> files
4916 Edit new include/configs/<myboard>.h
4921 Add / modify source code;
4925 email("Hi, I am having problems...");
4927 Send patch file to the U-Boot email list;
4928 if (reasonable critiques)
4929 Incorporate improvements from email list code review;
4931 Defend code as written;
4937 void no_more_time (int sig)
4946 All contributions to U-Boot should conform to the Linux kernel
4947 coding style; see the file "Documentation/CodingStyle" and the script
4948 "scripts/Lindent" in your Linux kernel source directory.
4950 Source files originating from a different project (for example the
4951 MTD subsystem) are generally exempt from these guidelines and are not
4952 reformated to ease subsequent migration to newer versions of those
4955 Please note that U-Boot is implemented in C (and to some small parts in
4956 Assembler); no C++ is used, so please do not use C++ style comments (//)
4959 Please also stick to the following formatting rules:
4960 - remove any trailing white space
4961 - use TAB characters for indentation and vertical alignment, not spaces
4962 - make sure NOT to use DOS '\r\n' line feeds
4963 - do not add more than 2 consecutive empty lines to source files
4964 - do not add trailing empty lines to source files
4966 Submissions which do not conform to the standards may be returned
4967 with a request to reformat the changes.
4973 Since the number of patches for U-Boot is growing, we need to
4974 establish some rules. Submissions which do not conform to these rules
4975 may be rejected, even when they contain important and valuable stuff.
4977 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4979 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4980 see http://lists.denx.de/mailman/listinfo/u-boot
4982 When you send a patch, please include the following information with
4985 * For bug fixes: a description of the bug and how your patch fixes
4986 this bug. Please try to include a way of demonstrating that the
4987 patch actually fixes something.
4989 * For new features: a description of the feature and your
4992 * A CHANGELOG entry as plaintext (separate from the patch)
4994 * For major contributions, your entry to the CREDITS file
4996 * When you add support for a new board, don't forget to add this
4997 board to the MAINTAINERS file, too.
4999 * If your patch adds new configuration options, don't forget to
5000 document these in the README file.
5002 * The patch itself. If you are using git (which is *strongly*
5003 recommended) you can easily generate the patch using the
5004 "git format-patch". If you then use "git send-email" to send it to
5005 the U-Boot mailing list, you will avoid most of the common problems
5006 with some other mail clients.
5008 If you cannot use git, use "diff -purN OLD NEW". If your version of
5009 diff does not support these options, then get the latest version of
5012 The current directory when running this command shall be the parent
5013 directory of the U-Boot source tree (i. e. please make sure that
5014 your patch includes sufficient directory information for the
5017 We prefer patches as plain text. MIME attachments are discouraged,
5018 and compressed attachments must not be used.
5020 * If one logical set of modifications affects or creates several
5021 files, all these changes shall be submitted in a SINGLE patch file.
5023 * Changesets that contain different, unrelated modifications shall be
5024 submitted as SEPARATE patches, one patch per changeset.
5029 * Before sending the patch, run the MAKEALL script on your patched
5030 source tree and make sure that no errors or warnings are reported
5031 for any of the boards.
5033 * Keep your modifications to the necessary minimum: A patch
5034 containing several unrelated changes or arbitrary reformats will be
5035 returned with a request to re-formatting / split it.
5037 * If you modify existing code, make sure that your new code does not
5038 add to the memory footprint of the code ;-) Small is beautiful!
5039 When adding new features, these should compile conditionally only
5040 (using #ifdef), and the resulting code with the new feature
5041 disabled must not need more memory than the old code without your
5044 * Remember that there is a size limit of 100 kB per message on the
5045 u-boot mailing list. Bigger patches will be moderated. If they are
5046 reasonable and not too big, they will be acknowledged. But patches
5047 bigger than the size limit should be avoided.