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 CONFIG_SYS_PPC_E500_DEBUG_TLB
379 Enables a temporary TLB entry to be used during boot to work
380 around limitations in e500v1 and e500v2 external debugger
381 support. This reduces the portions of the boot code where
382 breakpoints and single stepping do not work. The value of this
383 symbol should be set to the TLB1 entry to be used for this
386 - Generic CPU options:
387 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
389 Defines the endianess of the CPU. Implementation of those
390 values is arch specific.
392 - Intel Monahans options:
393 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
395 Defines the Monahans run mode to oscillator
396 ratio. Valid values are 8, 16, 24, 31. The core
397 frequency is this value multiplied by 13 MHz.
399 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
401 Defines the Monahans turbo mode to oscillator
402 ratio. Valid values are 1 (default if undefined) and
403 2. The core frequency as calculated above is multiplied
407 CONFIG_SYS_INIT_SP_OFFSET
409 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
410 pointer. This is needed for the temporary stack before
413 CONFIG_SYS_MIPS_CACHE_MODE
415 Cache operation mode for the MIPS CPU.
416 See also arch/mips/include/asm/mipsregs.h.
418 CONF_CM_CACHABLE_NO_WA
421 CONF_CM_CACHABLE_NONCOHERENT
425 CONF_CM_CACHABLE_ACCELERATED
427 CONFIG_SYS_XWAY_EBU_BOOTCFG
429 Special option for Lantiq XWAY SoCs for booting from NOR flash.
430 See also arch/mips/cpu/mips32/start.S.
432 CONFIG_XWAY_SWAP_BYTES
434 Enable compilation of tools/xway-swap-bytes needed for Lantiq
435 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
436 be swapped if a flash programmer is used.
439 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
441 Select high exception vectors of the ARM core, e.g., do not
442 clear the V bit of the c1 register of CP15.
444 CONFIG_SYS_THUMB_BUILD
446 Use this flag to build U-Boot using the Thumb instruction
447 set for ARM architectures. Thumb instruction set provides
448 better code density. For ARM architectures that support
449 Thumb2 this flag will result in Thumb2 code generated by
452 - Linux Kernel Interface:
455 U-Boot stores all clock information in Hz
456 internally. For binary compatibility with older Linux
457 kernels (which expect the clocks passed in the
458 bd_info data to be in MHz) the environment variable
459 "clocks_in_mhz" can be defined so that U-Boot
460 converts clock data to MHZ before passing it to the
462 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
463 "clocks_in_mhz=1" is automatically included in the
466 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
468 When transferring memsize parameter to linux, some versions
469 expect it to be in bytes, others in MB.
470 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
474 New kernel versions are expecting firmware settings to be
475 passed using flattened device trees (based on open firmware
479 * New libfdt-based support
480 * Adds the "fdt" command
481 * The bootm command automatically updates the fdt
483 OF_CPU - The proper name of the cpus node (only required for
484 MPC512X and MPC5xxx based boards).
485 OF_SOC - The proper name of the soc node (only required for
486 MPC512X and MPC5xxx based boards).
487 OF_TBCLK - The timebase frequency.
488 OF_STDOUT_PATH - The path to the console device
490 boards with QUICC Engines require OF_QE to set UCC MAC
493 CONFIG_OF_BOARD_SETUP
495 Board code has addition modification that it wants to make
496 to the flat device tree before handing it off to the kernel
500 This define fills in the correct boot CPU in the boot
501 param header, the default value is zero if undefined.
505 U-Boot can detect if an IDE device is present or not.
506 If not, and this new config option is activated, U-Boot
507 removes the ATA node from the DTS before booting Linux,
508 so the Linux IDE driver does not probe the device and
509 crash. This is needed for buggy hardware (uc101) where
510 no pull down resistor is connected to the signal IDE5V_DD7.
512 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
514 This setting is mandatory for all boards that have only one
515 machine type and must be used to specify the machine type
516 number as it appears in the ARM machine registry
517 (see http://www.arm.linux.org.uk/developer/machines/).
518 Only boards that have multiple machine types supported
519 in a single configuration file and the machine type is
520 runtime discoverable, do not have to use this setting.
522 - vxWorks boot parameters:
524 bootvx constructs a valid bootline using the following
525 environments variables: bootfile, ipaddr, serverip, hostname.
526 It loads the vxWorks image pointed bootfile.
528 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
529 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
530 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
531 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
533 CONFIG_SYS_VXWORKS_ADD_PARAMS
535 Add it at the end of the bootline. E.g "u=username pw=secret"
537 Note: If a "bootargs" environment is defined, it will overwride
538 the defaults discussed just above.
540 - Cache Configuration:
541 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
542 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
543 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
545 - Cache Configuration for ARM:
546 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
548 CONFIG_SYS_PL310_BASE - Physical base address of PL310
549 controller register space
554 Define this if you want support for Amba PrimeCell PL010 UARTs.
558 Define this if you want support for Amba PrimeCell PL011 UARTs.
562 If you have Amba PrimeCell PL011 UARTs, set this variable to
563 the clock speed of the UARTs.
567 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
568 define this to a list of base addresses for each (supported)
569 port. See e.g. include/configs/versatile.h
571 CONFIG_PL011_SERIAL_RLCR
573 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
574 have separate receive and transmit line control registers. Set
575 this variable to initialize the extra register.
577 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
579 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
580 boot loader that has already initialized the UART. Define this
581 variable to flush the UART at init time.
585 Depending on board, define exactly one serial port
586 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
587 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
588 console by defining CONFIG_8xx_CONS_NONE
590 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
591 port routines must be defined elsewhere
592 (i.e. serial_init(), serial_getc(), ...)
595 Enables console device for a color framebuffer. Needs following
596 defines (cf. smiLynxEM, i8042)
597 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
599 VIDEO_HW_RECTFILL graphic chip supports
602 VIDEO_HW_BITBLT graphic chip supports
603 bit-blit (cf. smiLynxEM)
604 VIDEO_VISIBLE_COLS visible pixel columns
606 VIDEO_VISIBLE_ROWS visible pixel rows
607 VIDEO_PIXEL_SIZE bytes per pixel
608 VIDEO_DATA_FORMAT graphic data format
609 (0-5, cf. cfb_console.c)
610 VIDEO_FB_ADRS framebuffer address
611 VIDEO_KBD_INIT_FCT keyboard int fct
612 (i.e. i8042_kbd_init())
613 VIDEO_TSTC_FCT test char fct
615 VIDEO_GETC_FCT get char fct
617 CONFIG_CONSOLE_CURSOR cursor drawing on/off
618 (requires blink timer
620 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
621 CONFIG_CONSOLE_TIME display time/date info in
623 (requires CONFIG_CMD_DATE)
624 CONFIG_VIDEO_LOGO display Linux logo in
626 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
627 linux_logo.h for logo.
628 Requires CONFIG_VIDEO_LOGO
629 CONFIG_CONSOLE_EXTRA_INFO
630 additional board info beside
633 When CONFIG_CFB_CONSOLE is defined, video console is
634 default i/o. Serial console can be forced with
635 environment 'console=serial'.
637 When CONFIG_SILENT_CONSOLE is defined, all console
638 messages (by U-Boot and Linux!) can be silenced with
639 the "silent" environment variable. See
640 doc/README.silent for more information.
643 CONFIG_BAUDRATE - in bps
644 Select one of the baudrates listed in
645 CONFIG_SYS_BAUDRATE_TABLE, see below.
646 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
648 - Console Rx buffer length
649 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
650 the maximum receive buffer length for the SMC.
651 This option is actual only for 82xx and 8xx possible.
652 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
653 must be defined, to setup the maximum idle timeout for
656 - Pre-Console Buffer:
657 Prior to the console being initialised (i.e. serial UART
658 initialised etc) all console output is silently discarded.
659 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
660 buffer any console messages prior to the console being
661 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
662 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
663 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
664 bytes are output before the console is initialised, the
665 earlier bytes are discarded.
667 'Sane' compilers will generate smaller code if
668 CONFIG_PRE_CON_BUF_SZ is a power of 2
670 - Safe printf() functions
671 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
672 the printf() functions. These are defined in
673 include/vsprintf.h and include snprintf(), vsnprintf() and
674 so on. Code size increase is approximately 300-500 bytes.
675 If this option is not given then these functions will
676 silently discard their buffer size argument - this means
677 you are not getting any overflow checking in this case.
679 - Boot Delay: CONFIG_BOOTDELAY - in seconds
680 Delay before automatically booting the default image;
681 set to -1 to disable autoboot.
683 See doc/README.autoboot for these options that
684 work with CONFIG_BOOTDELAY. None are required.
685 CONFIG_BOOT_RETRY_TIME
686 CONFIG_BOOT_RETRY_MIN
687 CONFIG_AUTOBOOT_KEYED
688 CONFIG_AUTOBOOT_PROMPT
689 CONFIG_AUTOBOOT_DELAY_STR
690 CONFIG_AUTOBOOT_STOP_STR
691 CONFIG_AUTOBOOT_DELAY_STR2
692 CONFIG_AUTOBOOT_STOP_STR2
693 CONFIG_ZERO_BOOTDELAY_CHECK
694 CONFIG_RESET_TO_RETRY
698 Only needed when CONFIG_BOOTDELAY is enabled;
699 define a command string that is automatically executed
700 when no character is read on the console interface
701 within "Boot Delay" after reset.
704 This can be used to pass arguments to the bootm
705 command. The value of CONFIG_BOOTARGS goes into the
706 environment value "bootargs".
708 CONFIG_RAMBOOT and CONFIG_NFSBOOT
709 The value of these goes into the environment as
710 "ramboot" and "nfsboot" respectively, and can be used
711 as a convenience, when switching between booting from
717 When this option is #defined, the existence of the
718 environment variable "preboot" will be checked
719 immediately before starting the CONFIG_BOOTDELAY
720 countdown and/or running the auto-boot command resp.
721 entering interactive mode.
723 This feature is especially useful when "preboot" is
724 automatically generated or modified. For an example
725 see the LWMON board specific code: here "preboot" is
726 modified when the user holds down a certain
727 combination of keys on the (special) keyboard when
730 - Serial Download Echo Mode:
732 If defined to 1, all characters received during a
733 serial download (using the "loads" command) are
734 echoed back. This might be needed by some terminal
735 emulations (like "cu"), but may as well just take
736 time on others. This setting #define's the initial
737 value of the "loads_echo" environment variable.
739 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
741 Select one of the baudrates listed in
742 CONFIG_SYS_BAUDRATE_TABLE, see below.
745 Monitor commands can be included or excluded
746 from the build by using the #include files
747 "config_cmd_all.h" and #undef'ing unwanted
748 commands, or using "config_cmd_default.h"
749 and augmenting with additional #define's
752 The default command configuration includes all commands
753 except those marked below with a "*".
755 CONFIG_CMD_ASKENV * ask for env variable
756 CONFIG_CMD_BDI bdinfo
757 CONFIG_CMD_BEDBUG * Include BedBug Debugger
758 CONFIG_CMD_BMP * BMP support
759 CONFIG_CMD_BSP * Board specific commands
760 CONFIG_CMD_BOOTD bootd
761 CONFIG_CMD_CACHE * icache, dcache
762 CONFIG_CMD_CONSOLE coninfo
763 CONFIG_CMD_CRC32 * crc32
764 CONFIG_CMD_DATE * support for RTC, date/time...
765 CONFIG_CMD_DHCP * DHCP support
766 CONFIG_CMD_DIAG * Diagnostics
767 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
768 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
769 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
770 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
771 CONFIG_CMD_DTT * Digital Therm and Thermostat
772 CONFIG_CMD_ECHO echo arguments
773 CONFIG_CMD_EDITENV edit env variable
774 CONFIG_CMD_EEPROM * EEPROM read/write support
775 CONFIG_CMD_ELF * bootelf, bootvx
776 CONFIG_CMD_EXPORTENV * export the environment
777 CONFIG_CMD_SAVEENV saveenv
778 CONFIG_CMD_FDC * Floppy Disk Support
779 CONFIG_CMD_FAT * FAT partition support
780 CONFIG_CMD_FDOS * Dos diskette Support
781 CONFIG_CMD_FLASH flinfo, erase, protect
782 CONFIG_CMD_FPGA FPGA device initialization support
783 CONFIG_CMD_GO * the 'go' command (exec code)
784 CONFIG_CMD_GREPENV * search environment
785 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
786 CONFIG_CMD_I2C * I2C serial bus support
787 CONFIG_CMD_IDE * IDE harddisk support
788 CONFIG_CMD_IMI iminfo
789 CONFIG_CMD_IMLS List all found images
790 CONFIG_CMD_IMMAP * IMMR dump support
791 CONFIG_CMD_IMPORTENV * import an environment
792 CONFIG_CMD_IRQ * irqinfo
793 CONFIG_CMD_ITEST Integer/string test of 2 values
794 CONFIG_CMD_JFFS2 * JFFS2 Support
795 CONFIG_CMD_KGDB * kgdb
796 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
797 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
799 CONFIG_CMD_LOADB loadb
800 CONFIG_CMD_LOADS loads
801 CONFIG_CMD_MD5SUM print md5 message digest
802 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
803 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
805 CONFIG_CMD_MISC Misc functions like sleep etc
806 CONFIG_CMD_MMC * MMC memory mapped support
807 CONFIG_CMD_MII * MII utility commands
808 CONFIG_CMD_MTDPARTS * MTD partition support
809 CONFIG_CMD_NAND * NAND support
810 CONFIG_CMD_NET bootp, tftpboot, rarpboot
811 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
812 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
813 CONFIG_CMD_PCI * pciinfo
814 CONFIG_CMD_PCMCIA * PCMCIA support
815 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
817 CONFIG_CMD_PORTIO * Port I/O
818 CONFIG_CMD_REGINFO * Register dump
819 CONFIG_CMD_RUN run command in env variable
820 CONFIG_CMD_SAVES * save S record dump
821 CONFIG_CMD_SCSI * SCSI Support
822 CONFIG_CMD_SDRAM * print SDRAM configuration information
823 (requires CONFIG_CMD_I2C)
824 CONFIG_CMD_SETGETDCR Support for DCR Register access
826 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
827 CONFIG_CMD_SHA1SUM print sha1 memory digest
828 (requires CONFIG_CMD_MEMORY)
829 CONFIG_CMD_SOURCE "source" command Support
830 CONFIG_CMD_SPI * SPI serial bus support
831 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
832 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
833 CONFIG_CMD_TIME * run command and report execution time
834 CONFIG_CMD_USB * USB support
835 CONFIG_CMD_CDP * Cisco Discover Protocol support
836 CONFIG_CMD_MFSL * Microblaze FSL support
839 EXAMPLE: If you want all functions except of network
840 support you can write:
842 #include "config_cmd_all.h"
843 #undef CONFIG_CMD_NET
846 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
848 Note: Don't enable the "icache" and "dcache" commands
849 (configuration option CONFIG_CMD_CACHE) unless you know
850 what you (and your U-Boot users) are doing. Data
851 cache cannot be enabled on systems like the 8xx or
852 8260 (where accesses to the IMMR region must be
853 uncached), and it cannot be disabled on all other
854 systems where we (mis-) use the data cache to hold an
855 initial stack and some data.
858 XXX - this list needs to get updated!
862 If this variable is defined, U-Boot will use a device tree
863 to configure its devices, instead of relying on statically
864 compiled #defines in the board file. This option is
865 experimental and only available on a few boards. The device
866 tree is available in the global data as gd->fdt_blob.
868 U-Boot needs to get its device tree from somewhere. This can
869 be done using one of the two options below:
872 If this variable is defined, U-Boot will embed a device tree
873 binary in its image. This device tree file should be in the
874 board directory and called <soc>-<board>.dts. The binary file
875 is then picked up in board_init_f() and made available through
876 the global data structure as gd->blob.
879 If this variable is defined, U-Boot will build a device tree
880 binary. It will be called u-boot.dtb. Architecture-specific
881 code will locate it at run-time. Generally this works by:
883 cat u-boot.bin u-boot.dtb >image.bin
885 and in fact, U-Boot does this for you, creating a file called
886 u-boot-dtb.bin which is useful in the common case. You can
887 still use the individual files if you need something more
892 If this variable is defined, it enables watchdog
893 support for the SoC. There must be support in the SoC
894 specific code for a watchdog. For the 8xx and 8260
895 CPUs, the SIU Watchdog feature is enabled in the SYPCR
896 register. When supported for a specific SoC is
897 available, then no further board specific code should
901 When using a watchdog circuitry external to the used
902 SoC, then define this variable and provide board
903 specific code for the "hw_watchdog_reset" function.
906 CONFIG_VERSION_VARIABLE
907 If this variable is defined, an environment variable
908 named "ver" is created by U-Boot showing the U-Boot
909 version as printed by the "version" command.
910 This variable is readonly.
914 When CONFIG_CMD_DATE is selected, the type of the RTC
915 has to be selected, too. Define exactly one of the
918 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
919 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
920 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
921 CONFIG_RTC_MC146818 - use MC146818 RTC
922 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
923 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
924 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
925 CONFIG_RTC_DS164x - use Dallas DS164x RTC
926 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
927 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
928 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
929 CONFIG_SYS_RV3029_TCR - enable trickle charger on
932 Note that if the RTC uses I2C, then the I2C interface
933 must also be configured. See I2C Support, below.
936 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
937 CONFIG_PCA953X_INFO - enable pca953x info command
939 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
940 chip-ngpio pairs that tell the PCA953X driver the number of
941 pins supported by a particular chip.
943 Note that if the GPIO device uses I2C, then the I2C interface
944 must also be configured. See I2C Support, below.
948 When CONFIG_TIMESTAMP is selected, the timestamp
949 (date and time) of an image is printed by image
950 commands like bootm or iminfo. This option is
951 automatically enabled when you select CONFIG_CMD_DATE .
954 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
955 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
957 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
958 CONFIG_CMD_SCSI) you must configure support for at
959 least one partition type as well.
962 CONFIG_IDE_RESET_ROUTINE - this is defined in several
963 board configurations files but used nowhere!
965 CONFIG_IDE_RESET - is this is defined, IDE Reset will
966 be performed by calling the function
967 ide_set_reset(int reset)
968 which has to be defined in a board specific file
973 Set this to enable ATAPI support.
978 Set this to enable support for disks larger than 137GB
979 Also look at CONFIG_SYS_64BIT_LBA.
980 Whithout these , LBA48 support uses 32bit variables and will 'only'
981 support disks up to 2.1TB.
983 CONFIG_SYS_64BIT_LBA:
984 When enabled, makes the IDE subsystem use 64bit sector addresses.
988 At the moment only there is only support for the
989 SYM53C8XX SCSI controller; define
990 CONFIG_SCSI_SYM53C8XX to enable it.
992 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
993 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
994 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
995 maximum numbers of LUNs, SCSI ID's and target
997 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
999 - NETWORK Support (PCI):
1001 Support for Intel 8254x/8257x gigabit chips.
1004 Utility code for direct access to the SPI bus on Intel 8257x.
1005 This does not do anything useful unless you set at least one
1006 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1008 CONFIG_E1000_SPI_GENERIC
1009 Allow generic access to the SPI bus on the Intel 8257x, for
1010 example with the "sspi" command.
1013 Management command for E1000 devices. When used on devices
1014 with SPI support you can reprogram the EEPROM from U-Boot.
1016 CONFIG_E1000_FALLBACK_MAC
1017 default MAC for empty EEPROM after production.
1020 Support for Intel 82557/82559/82559ER chips.
1021 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1022 write routine for first time initialisation.
1025 Support for Digital 2114x chips.
1026 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1027 modem chip initialisation (KS8761/QS6611).
1030 Support for National dp83815 chips.
1033 Support for National dp8382[01] gigabit chips.
1035 - NETWORK Support (other):
1037 CONFIG_DRIVER_AT91EMAC
1038 Support for AT91RM9200 EMAC.
1041 Define this to use reduced MII inteface
1043 CONFIG_DRIVER_AT91EMAC_QUIET
1044 If this defined, the driver is quiet.
1045 The driver doen't show link status messages.
1047 CONFIG_CALXEDA_XGMAC
1048 Support for the Calxeda XGMAC device
1050 CONFIG_DRIVER_LAN91C96
1051 Support for SMSC's LAN91C96 chips.
1053 CONFIG_LAN91C96_BASE
1054 Define this to hold the physical address
1055 of the LAN91C96's I/O space
1057 CONFIG_LAN91C96_USE_32_BIT
1058 Define this to enable 32 bit addressing
1060 CONFIG_DRIVER_SMC91111
1061 Support for SMSC's LAN91C111 chip
1063 CONFIG_SMC91111_BASE
1064 Define this to hold the physical address
1065 of the device (I/O space)
1067 CONFIG_SMC_USE_32_BIT
1068 Define this if data bus is 32 bits
1070 CONFIG_SMC_USE_IOFUNCS
1071 Define this to use i/o functions instead of macros
1072 (some hardware wont work with macros)
1074 CONFIG_DRIVER_TI_EMAC
1075 Support for davinci emac
1077 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1078 Define this if you have more then 3 PHYs.
1081 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1083 CONFIG_FTGMAC100_EGIGA
1084 Define this to use GE link update with gigabit PHY.
1085 Define this if FTGMAC100 is connected to gigabit PHY.
1086 If your system has 10/100 PHY only, it might not occur
1087 wrong behavior. Because PHY usually return timeout or
1088 useless data when polling gigabit status and gigabit
1089 control registers. This behavior won't affect the
1090 correctnessof 10/100 link speed update.
1093 Support for SMSC's LAN911x and LAN921x chips
1096 Define this to hold the physical address
1097 of the device (I/O space)
1099 CONFIG_SMC911X_32_BIT
1100 Define this if data bus is 32 bits
1102 CONFIG_SMC911X_16_BIT
1103 Define this if data bus is 16 bits. If your processor
1104 automatically converts one 32 bit word to two 16 bit
1105 words you may also try CONFIG_SMC911X_32_BIT.
1108 Support for Renesas on-chip Ethernet controller
1110 CONFIG_SH_ETHER_USE_PORT
1111 Define the number of ports to be used
1113 CONFIG_SH_ETHER_PHY_ADDR
1114 Define the ETH PHY's address
1116 CONFIG_SH_ETHER_CACHE_WRITEBACK
1117 If this option is set, the driver enables cache flush.
1120 CONFIG_GENERIC_LPC_TPM
1121 Support for generic parallel port TPM devices. Only one device
1122 per system is supported at this time.
1124 CONFIG_TPM_TIS_BASE_ADDRESS
1125 Base address where the generic TPM device is mapped
1126 to. Contemporary x86 systems usually map it at
1130 At the moment only the UHCI host controller is
1131 supported (PIP405, MIP405, MPC5200); define
1132 CONFIG_USB_UHCI to enable it.
1133 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1134 and define CONFIG_USB_STORAGE to enable the USB
1137 Supported are USB Keyboards and USB Floppy drives
1139 MPC5200 USB requires additional defines:
1141 for 528 MHz Clock: 0x0001bbbb
1145 for differential drivers: 0x00001000
1146 for single ended drivers: 0x00005000
1147 for differential drivers on PSC3: 0x00000100
1148 for single ended drivers on PSC3: 0x00004100
1149 CONFIG_SYS_USB_EVENT_POLL
1150 May be defined to allow interrupt polling
1151 instead of using asynchronous interrupts
1153 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1154 txfilltuning field in the EHCI controller on reset.
1157 Define the below if you wish to use the USB console.
1158 Once firmware is rebuilt from a serial console issue the
1159 command "setenv stdin usbtty; setenv stdout usbtty" and
1160 attach your USB cable. The Unix command "dmesg" should print
1161 it has found a new device. The environment variable usbtty
1162 can be set to gserial or cdc_acm to enable your device to
1163 appear to a USB host as a Linux gserial device or a
1164 Common Device Class Abstract Control Model serial device.
1165 If you select usbtty = gserial you should be able to enumerate
1167 # modprobe usbserial vendor=0xVendorID product=0xProductID
1168 else if using cdc_acm, simply setting the environment
1169 variable usbtty to be cdc_acm should suffice. The following
1170 might be defined in YourBoardName.h
1173 Define this to build a UDC device
1176 Define this to have a tty type of device available to
1177 talk to the UDC device
1180 Define this to enable the high speed support for usb
1181 device and usbtty. If this feature is enabled, a routine
1182 int is_usbd_high_speed(void)
1183 also needs to be defined by the driver to dynamically poll
1184 whether the enumeration has succeded at high speed or full
1187 CONFIG_SYS_CONSOLE_IS_IN_ENV
1188 Define this if you want stdin, stdout &/or stderr to
1192 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1193 Derive USB clock from external clock "blah"
1194 - CONFIG_SYS_USB_EXTC_CLK 0x02
1196 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1197 Derive USB clock from brgclk
1198 - CONFIG_SYS_USB_BRG_CLK 0x04
1200 If you have a USB-IF assigned VendorID then you may wish to
1201 define your own vendor specific values either in BoardName.h
1202 or directly in usbd_vendor_info.h. If you don't define
1203 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1204 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1205 should pretend to be a Linux device to it's target host.
1207 CONFIG_USBD_MANUFACTURER
1208 Define this string as the name of your company for
1209 - CONFIG_USBD_MANUFACTURER "my company"
1211 CONFIG_USBD_PRODUCT_NAME
1212 Define this string as the name of your product
1213 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1215 CONFIG_USBD_VENDORID
1216 Define this as your assigned Vendor ID from the USB
1217 Implementors Forum. This *must* be a genuine Vendor ID
1218 to avoid polluting the USB namespace.
1219 - CONFIG_USBD_VENDORID 0xFFFF
1221 CONFIG_USBD_PRODUCTID
1222 Define this as the unique Product ID
1224 - CONFIG_USBD_PRODUCTID 0xFFFF
1226 - ULPI Layer Support:
1227 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1228 the generic ULPI layer. The generic layer accesses the ULPI PHY
1229 via the platform viewport, so you need both the genric layer and
1230 the viewport enabled. Currently only Chipidea/ARC based
1231 viewport is supported.
1232 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1233 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1236 The MMC controller on the Intel PXA is supported. To
1237 enable this define CONFIG_MMC. The MMC can be
1238 accessed from the boot prompt by mapping the device
1239 to physical memory similar to flash. Command line is
1240 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1241 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1244 Support for Renesas on-chip MMCIF controller
1246 CONFIG_SH_MMCIF_ADDR
1247 Define the base address of MMCIF registers
1250 Define the clock frequency for MMCIF
1252 - Journaling Flash filesystem support:
1253 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1254 CONFIG_JFFS2_NAND_DEV
1255 Define these for a default partition on a NAND device
1257 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1258 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1259 Define these for a default partition on a NOR device
1261 CONFIG_SYS_JFFS_CUSTOM_PART
1262 Define this to create an own partition. You have to provide a
1263 function struct part_info* jffs2_part_info(int part_num)
1265 If you define only one JFFS2 partition you may also want to
1266 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1267 to disable the command chpart. This is the default when you
1268 have not defined a custom partition
1270 - FAT(File Allocation Table) filesystem write function support:
1273 Define this to enable support for saving memory data as a
1274 file in FAT formatted partition.
1276 This will also enable the command "fatwrite" enabling the
1277 user to write files to FAT.
1282 Define this to enable standard (PC-Style) keyboard
1286 Standard PC keyboard driver with US (is default) and
1287 GERMAN key layout (switch via environment 'keymap=de') support.
1288 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1289 for cfb_console. Supports cursor blinking.
1294 Define this to enable video support (for output to
1297 CONFIG_VIDEO_CT69000
1299 Enable Chips & Technologies 69000 Video chip
1301 CONFIG_VIDEO_SMI_LYNXEM
1302 Enable Silicon Motion SMI 712/710/810 Video chip. The
1303 video output is selected via environment 'videoout'
1304 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1307 For the CT69000 and SMI_LYNXEM drivers, videomode is
1308 selected via environment 'videomode'. Two different ways
1310 - "videomode=num" 'num' is a standard LiLo mode numbers.
1311 Following standard modes are supported (* is default):
1313 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1314 -------------+---------------------------------------------
1315 8 bits | 0x301* 0x303 0x305 0x161 0x307
1316 15 bits | 0x310 0x313 0x316 0x162 0x319
1317 16 bits | 0x311 0x314 0x317 0x163 0x31A
1318 24 bits | 0x312 0x315 0x318 ? 0x31B
1319 -------------+---------------------------------------------
1320 (i.e. setenv videomode 317; saveenv; reset;)
1322 - "videomode=bootargs" all the video parameters are parsed
1323 from the bootargs. (See drivers/video/videomodes.c)
1326 CONFIG_VIDEO_SED13806
1327 Enable Epson SED13806 driver. This driver supports 8bpp
1328 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1329 or CONFIG_VIDEO_SED13806_16BPP
1332 Enable the Freescale DIU video driver. Reference boards for
1333 SOCs that have a DIU should define this macro to enable DIU
1334 support, and should also define these other macros:
1340 CONFIG_VIDEO_SW_CURSOR
1341 CONFIG_VGA_AS_SINGLE_DEVICE
1343 CONFIG_VIDEO_BMP_LOGO
1345 The DIU driver will look for the 'video-mode' environment
1346 variable, and if defined, enable the DIU as a console during
1347 boot. See the documentation file README.video for a
1348 description of this variable.
1353 Define this to enable a custom keyboard support.
1354 This simply calls drv_keyboard_init() which must be
1355 defined in your board-specific files.
1356 The only board using this so far is RBC823.
1358 - LCD Support: CONFIG_LCD
1360 Define this to enable LCD support (for output to LCD
1361 display); also select one of the supported displays
1362 by defining one of these:
1366 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1368 CONFIG_NEC_NL6448AC33:
1370 NEC NL6448AC33-18. Active, color, single scan.
1372 CONFIG_NEC_NL6448BC20
1374 NEC NL6448BC20-08. 6.5", 640x480.
1375 Active, color, single scan.
1377 CONFIG_NEC_NL6448BC33_54
1379 NEC NL6448BC33-54. 10.4", 640x480.
1380 Active, color, single scan.
1384 Sharp 320x240. Active, color, single scan.
1385 It isn't 16x9, and I am not sure what it is.
1387 CONFIG_SHARP_LQ64D341
1389 Sharp LQ64D341 display, 640x480.
1390 Active, color, single scan.
1394 HLD1045 display, 640x480.
1395 Active, color, single scan.
1399 Optrex CBL50840-2 NF-FW 99 22 M5
1401 Hitachi LMG6912RPFC-00T
1405 320x240. Black & white.
1407 Normally display is black on white background; define
1408 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1410 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1412 If this option is set, the environment is checked for
1413 a variable "splashimage". If found, the usual display
1414 of logo, copyright and system information on the LCD
1415 is suppressed and the BMP image at the address
1416 specified in "splashimage" is loaded instead. The
1417 console is redirected to the "nulldev", too. This
1418 allows for a "silent" boot where a splash screen is
1419 loaded very quickly after power-on.
1421 CONFIG_SPLASH_SCREEN_ALIGN
1423 If this option is set the splash image can be freely positioned
1424 on the screen. Environment variable "splashpos" specifies the
1425 position as "x,y". If a positive number is given it is used as
1426 number of pixel from left/top. If a negative number is given it
1427 is used as number of pixel from right/bottom. You can also
1428 specify 'm' for centering the image.
1431 setenv splashpos m,m
1432 => image at center of screen
1434 setenv splashpos 30,20
1435 => image at x = 30 and y = 20
1437 setenv splashpos -10,m
1438 => vertically centered image
1439 at x = dspWidth - bmpWidth - 9
1441 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1443 If this option is set, additionally to standard BMP
1444 images, gzipped BMP images can be displayed via the
1445 splashscreen support or the bmp command.
1447 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1449 If this option is set, 8-bit RLE compressed BMP images
1450 can be displayed via the splashscreen support or the
1453 - Compression support:
1456 If this option is set, support for bzip2 compressed
1457 images is included. If not, only uncompressed and gzip
1458 compressed images are supported.
1460 NOTE: the bzip2 algorithm requires a lot of RAM, so
1461 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1466 If this option is set, support for lzma compressed
1469 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1470 requires an amount of dynamic memory that is given by the
1473 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1475 Where lc and lp stand for, respectively, Literal context bits
1476 and Literal pos bits.
1478 This value is upper-bounded by 14MB in the worst case. Anyway,
1479 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1480 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1481 a very small buffer.
1483 Use the lzmainfo tool to determinate the lc and lp values and
1484 then calculate the amount of needed dynamic memory (ensuring
1485 the appropriate CONFIG_SYS_MALLOC_LEN value).
1490 The address of PHY on MII bus.
1492 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1494 The clock frequency of the MII bus
1498 If this option is set, support for speed/duplex
1499 detection of gigabit PHY is included.
1501 CONFIG_PHY_RESET_DELAY
1503 Some PHY like Intel LXT971A need extra delay after
1504 reset before any MII register access is possible.
1505 For such PHY, set this option to the usec delay
1506 required. (minimum 300usec for LXT971A)
1508 CONFIG_PHY_CMD_DELAY (ppc4xx)
1510 Some PHY like Intel LXT971A need extra delay after
1511 command issued before MII status register can be read
1521 Define a default value for Ethernet address to use
1522 for the respective Ethernet interface, in case this
1523 is not determined automatically.
1528 Define a default value for the IP address to use for
1529 the default Ethernet interface, in case this is not
1530 determined through e.g. bootp.
1531 (Environment variable "ipaddr")
1533 - Server IP address:
1536 Defines a default value for the IP address of a TFTP
1537 server to contact when using the "tftboot" command.
1538 (Environment variable "serverip")
1540 CONFIG_KEEP_SERVERADDR
1542 Keeps the server's MAC address, in the env 'serveraddr'
1543 for passing to bootargs (like Linux's netconsole option)
1545 - Gateway IP address:
1548 Defines a default value for the IP address of the
1549 default router where packets to other networks are
1551 (Environment variable "gatewayip")
1556 Defines a default value for the subnet mask (or
1557 routing prefix) which is used to determine if an IP
1558 address belongs to the local subnet or needs to be
1559 forwarded through a router.
1560 (Environment variable "netmask")
1562 - Multicast TFTP Mode:
1565 Defines whether you want to support multicast TFTP as per
1566 rfc-2090; for example to work with atftp. Lets lots of targets
1567 tftp down the same boot image concurrently. Note: the Ethernet
1568 driver in use must provide a function: mcast() to join/leave a
1571 - BOOTP Recovery Mode:
1572 CONFIG_BOOTP_RANDOM_DELAY
1574 If you have many targets in a network that try to
1575 boot using BOOTP, you may want to avoid that all
1576 systems send out BOOTP requests at precisely the same
1577 moment (which would happen for instance at recovery
1578 from a power failure, when all systems will try to
1579 boot, thus flooding the BOOTP server. Defining
1580 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1581 inserted before sending out BOOTP requests. The
1582 following delays are inserted then:
1584 1st BOOTP request: delay 0 ... 1 sec
1585 2nd BOOTP request: delay 0 ... 2 sec
1586 3rd BOOTP request: delay 0 ... 4 sec
1588 BOOTP requests: delay 0 ... 8 sec
1590 - DHCP Advanced Options:
1591 You can fine tune the DHCP functionality by defining
1592 CONFIG_BOOTP_* symbols:
1594 CONFIG_BOOTP_SUBNETMASK
1595 CONFIG_BOOTP_GATEWAY
1596 CONFIG_BOOTP_HOSTNAME
1597 CONFIG_BOOTP_NISDOMAIN
1598 CONFIG_BOOTP_BOOTPATH
1599 CONFIG_BOOTP_BOOTFILESIZE
1602 CONFIG_BOOTP_SEND_HOSTNAME
1603 CONFIG_BOOTP_NTPSERVER
1604 CONFIG_BOOTP_TIMEOFFSET
1605 CONFIG_BOOTP_VENDOREX
1606 CONFIG_BOOTP_MAY_FAIL
1608 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1609 environment variable, not the BOOTP server.
1611 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1612 after the configured retry count, the call will fail
1613 instead of starting over. This can be used to fail over
1614 to Link-local IP address configuration if the DHCP server
1617 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1618 serverip from a DHCP server, it is possible that more
1619 than one DNS serverip is offered to the client.
1620 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1621 serverip will be stored in the additional environment
1622 variable "dnsip2". The first DNS serverip is always
1623 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1626 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1627 to do a dynamic update of a DNS server. To do this, they
1628 need the hostname of the DHCP requester.
1629 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1630 of the "hostname" environment variable is passed as
1631 option 12 to the DHCP server.
1633 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1635 A 32bit value in microseconds for a delay between
1636 receiving a "DHCP Offer" and sending the "DHCP Request".
1637 This fixes a problem with certain DHCP servers that don't
1638 respond 100% of the time to a "DHCP request". E.g. On an
1639 AT91RM9200 processor running at 180MHz, this delay needed
1640 to be *at least* 15,000 usec before a Windows Server 2003
1641 DHCP server would reply 100% of the time. I recommend at
1642 least 50,000 usec to be safe. The alternative is to hope
1643 that one of the retries will be successful but note that
1644 the DHCP timeout and retry process takes a longer than
1647 - Link-local IP address negotiation:
1648 Negotiate with other link-local clients on the local network
1649 for an address that doesn't require explicit configuration.
1650 This is especially useful if a DHCP server cannot be guaranteed
1651 to exist in all environments that the device must operate.
1653 See doc/README.link-local for more information.
1656 CONFIG_CDP_DEVICE_ID
1658 The device id used in CDP trigger frames.
1660 CONFIG_CDP_DEVICE_ID_PREFIX
1662 A two character string which is prefixed to the MAC address
1667 A printf format string which contains the ascii name of
1668 the port. Normally is set to "eth%d" which sets
1669 eth0 for the first Ethernet, eth1 for the second etc.
1671 CONFIG_CDP_CAPABILITIES
1673 A 32bit integer which indicates the device capabilities;
1674 0x00000010 for a normal host which does not forwards.
1678 An ascii string containing the version of the software.
1682 An ascii string containing the name of the platform.
1686 A 32bit integer sent on the trigger.
1688 CONFIG_CDP_POWER_CONSUMPTION
1690 A 16bit integer containing the power consumption of the
1691 device in .1 of milliwatts.
1693 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1695 A byte containing the id of the VLAN.
1697 - Status LED: CONFIG_STATUS_LED
1699 Several configurations allow to display the current
1700 status using a LED. For instance, the LED will blink
1701 fast while running U-Boot code, stop blinking as
1702 soon as a reply to a BOOTP request was received, and
1703 start blinking slow once the Linux kernel is running
1704 (supported by a status LED driver in the Linux
1705 kernel). Defining CONFIG_STATUS_LED enables this
1708 - CAN Support: CONFIG_CAN_DRIVER
1710 Defining CONFIG_CAN_DRIVER enables CAN driver support
1711 on those systems that support this (optional)
1712 feature, like the TQM8xxL modules.
1714 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1716 These enable I2C serial bus commands. Defining either of
1717 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1718 include the appropriate I2C driver for the selected CPU.
1720 This will allow you to use i2c commands at the u-boot
1721 command line (as long as you set CONFIG_CMD_I2C in
1722 CONFIG_COMMANDS) and communicate with i2c based realtime
1723 clock chips. See common/cmd_i2c.c for a description of the
1724 command line interface.
1726 CONFIG_HARD_I2C selects a hardware I2C controller.
1728 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1729 bit-banging) driver instead of CPM or similar hardware
1732 There are several other quantities that must also be
1733 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1735 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1736 to be the frequency (in Hz) at which you wish your i2c bus
1737 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1738 the CPU's i2c node address).
1740 Now, the u-boot i2c code for the mpc8xx
1741 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1742 and so its address should therefore be cleared to 0 (See,
1743 eg, MPC823e User's Manual p.16-473). So, set
1744 CONFIG_SYS_I2C_SLAVE to 0.
1746 CONFIG_SYS_I2C_INIT_MPC5XXX
1748 When a board is reset during an i2c bus transfer
1749 chips might think that the current transfer is still
1750 in progress. Reset the slave devices by sending start
1751 commands until the slave device responds.
1753 That's all that's required for CONFIG_HARD_I2C.
1755 If you use the software i2c interface (CONFIG_SOFT_I2C)
1756 then the following macros need to be defined (examples are
1757 from include/configs/lwmon.h):
1761 (Optional). Any commands necessary to enable the I2C
1762 controller or configure ports.
1764 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1768 (Only for MPC8260 CPU). The I/O port to use (the code
1769 assumes both bits are on the same port). Valid values
1770 are 0..3 for ports A..D.
1774 The code necessary to make the I2C data line active
1775 (driven). If the data line is open collector, this
1778 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1782 The code necessary to make the I2C data line tri-stated
1783 (inactive). If the data line is open collector, this
1786 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1790 Code that returns TRUE if the I2C data line is high,
1793 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1797 If <bit> is TRUE, sets the I2C data line high. If it
1798 is FALSE, it clears it (low).
1800 eg: #define I2C_SDA(bit) \
1801 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1802 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1806 If <bit> is TRUE, sets the I2C clock line high. If it
1807 is FALSE, it clears it (low).
1809 eg: #define I2C_SCL(bit) \
1810 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1811 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1815 This delay is invoked four times per clock cycle so this
1816 controls the rate of data transfer. The data rate thus
1817 is 1 / (I2C_DELAY * 4). Often defined to be something
1820 #define I2C_DELAY udelay(2)
1822 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1824 If your arch supports the generic GPIO framework (asm/gpio.h),
1825 then you may alternatively define the two GPIOs that are to be
1826 used as SCL / SDA. Any of the previous I2C_xxx macros will
1827 have GPIO-based defaults assigned to them as appropriate.
1829 You should define these to the GPIO value as given directly to
1830 the generic GPIO functions.
1832 CONFIG_SYS_I2C_INIT_BOARD
1834 When a board is reset during an i2c bus transfer
1835 chips might think that the current transfer is still
1836 in progress. On some boards it is possible to access
1837 the i2c SCLK line directly, either by using the
1838 processor pin as a GPIO or by having a second pin
1839 connected to the bus. If this option is defined a
1840 custom i2c_init_board() routine in boards/xxx/board.c
1841 is run early in the boot sequence.
1843 CONFIG_SYS_I2C_BOARD_LATE_INIT
1845 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1846 defined a custom i2c_board_late_init() routine in
1847 boards/xxx/board.c is run AFTER the operations in i2c_init()
1848 is completed. This callpoint can be used to unreset i2c bus
1849 using CPU i2c controller register accesses for CPUs whose i2c
1850 controller provide such a method. It is called at the end of
1851 i2c_init() to allow i2c_init operations to setup the i2c bus
1852 controller on the CPU (e.g. setting bus speed & slave address).
1854 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1856 This option enables configuration of bi_iic_fast[] flags
1857 in u-boot bd_info structure based on u-boot environment
1858 variable "i2cfast". (see also i2cfast)
1860 CONFIG_I2C_MULTI_BUS
1862 This option allows the use of multiple I2C buses, each of which
1863 must have a controller. At any point in time, only one bus is
1864 active. To switch to a different bus, use the 'i2c dev' command.
1865 Note that bus numbering is zero-based.
1867 CONFIG_SYS_I2C_NOPROBES
1869 This option specifies a list of I2C devices that will be skipped
1870 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1871 is set, specify a list of bus-device pairs. Otherwise, specify
1872 a 1D array of device addresses
1875 #undef CONFIG_I2C_MULTI_BUS
1876 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1878 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1880 #define CONFIG_I2C_MULTI_BUS
1881 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1883 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1885 CONFIG_SYS_SPD_BUS_NUM
1887 If defined, then this indicates the I2C bus number for DDR SPD.
1888 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1890 CONFIG_SYS_RTC_BUS_NUM
1892 If defined, then this indicates the I2C bus number for the RTC.
1893 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1895 CONFIG_SYS_DTT_BUS_NUM
1897 If defined, then this indicates the I2C bus number for the DTT.
1898 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1900 CONFIG_SYS_I2C_DTT_ADDR:
1902 If defined, specifies the I2C address of the DTT device.
1903 If not defined, then U-Boot uses predefined value for
1904 specified DTT device.
1908 Define this option if you want to use Freescale's I2C driver in
1909 drivers/i2c/fsl_i2c.c.
1913 Define this option if you have I2C devices reached over 1 .. n
1914 I2C Muxes like the pca9544a. This option addes a new I2C
1915 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1916 new I2C Bus to the existing I2C Busses. If you select the
1917 new Bus with "i2c dev", u-bbot sends first the commandos for
1918 the muxes to activate this new "bus".
1920 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1924 Adding a new I2C Bus reached over 2 pca9544a muxes
1925 The First mux with address 70 and channel 6
1926 The Second mux with address 71 and channel 4
1928 => i2c bus pca9544a:70:6:pca9544a:71:4
1930 Use the "i2c bus" command without parameter, to get a list
1931 of I2C Busses with muxes:
1934 Busses reached over muxes:
1936 reached over Mux(es):
1939 reached over Mux(es):
1944 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1945 u-boot first sends the command to the mux@70 to enable
1946 channel 6, and then the command to the mux@71 to enable
1949 After that, you can use the "normal" i2c commands as
1950 usual to communicate with your I2C devices behind
1953 This option is actually implemented for the bitbanging
1954 algorithm in common/soft_i2c.c and for the Hardware I2C
1955 Bus on the MPC8260. But it should be not so difficult
1956 to add this option to other architectures.
1958 CONFIG_SOFT_I2C_READ_REPEATED_START
1960 defining this will force the i2c_read() function in
1961 the soft_i2c driver to perform an I2C repeated start
1962 between writing the address pointer and reading the
1963 data. If this define is omitted the default behaviour
1964 of doing a stop-start sequence will be used. Most I2C
1965 devices can use either method, but some require one or
1968 - SPI Support: CONFIG_SPI
1970 Enables SPI driver (so far only tested with
1971 SPI EEPROM, also an instance works with Crystal A/D and
1972 D/As on the SACSng board)
1976 Enables the driver for SPI controller on SuperH. Currently
1977 only SH7757 is supported.
1981 Enables extended (16-bit) SPI EEPROM addressing.
1982 (symmetrical to CONFIG_I2C_X)
1986 Enables a software (bit-bang) SPI driver rather than
1987 using hardware support. This is a general purpose
1988 driver that only requires three general I/O port pins
1989 (two outputs, one input) to function. If this is
1990 defined, the board configuration must define several
1991 SPI configuration items (port pins to use, etc). For
1992 an example, see include/configs/sacsng.h.
1996 Enables a hardware SPI driver for general-purpose reads
1997 and writes. As with CONFIG_SOFT_SPI, the board configuration
1998 must define a list of chip-select function pointers.
1999 Currently supported on some MPC8xxx processors. For an
2000 example, see include/configs/mpc8349emds.h.
2004 Enables the driver for the SPI controllers on i.MX and MXC
2005 SoCs. Currently i.MX31/35/51 are supported.
2007 - FPGA Support: CONFIG_FPGA
2009 Enables FPGA subsystem.
2011 CONFIG_FPGA_<vendor>
2013 Enables support for specific chip vendors.
2016 CONFIG_FPGA_<family>
2018 Enables support for FPGA family.
2019 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2023 Specify the number of FPGA devices to support.
2025 CONFIG_SYS_FPGA_PROG_FEEDBACK
2027 Enable printing of hash marks during FPGA configuration.
2029 CONFIG_SYS_FPGA_CHECK_BUSY
2031 Enable checks on FPGA configuration interface busy
2032 status by the configuration function. This option
2033 will require a board or device specific function to
2038 If defined, a function that provides delays in the FPGA
2039 configuration driver.
2041 CONFIG_SYS_FPGA_CHECK_CTRLC
2042 Allow Control-C to interrupt FPGA configuration
2044 CONFIG_SYS_FPGA_CHECK_ERROR
2046 Check for configuration errors during FPGA bitfile
2047 loading. For example, abort during Virtex II
2048 configuration if the INIT_B line goes low (which
2049 indicated a CRC error).
2051 CONFIG_SYS_FPGA_WAIT_INIT
2053 Maximum time to wait for the INIT_B line to deassert
2054 after PROB_B has been deasserted during a Virtex II
2055 FPGA configuration sequence. The default time is 500
2058 CONFIG_SYS_FPGA_WAIT_BUSY
2060 Maximum time to wait for BUSY to deassert during
2061 Virtex II FPGA configuration. The default is 5 ms.
2063 CONFIG_SYS_FPGA_WAIT_CONFIG
2065 Time to wait after FPGA configuration. The default is
2068 - Configuration Management:
2071 If defined, this string will be added to the U-Boot
2072 version information (U_BOOT_VERSION)
2074 - Vendor Parameter Protection:
2076 U-Boot considers the values of the environment
2077 variables "serial#" (Board Serial Number) and
2078 "ethaddr" (Ethernet Address) to be parameters that
2079 are set once by the board vendor / manufacturer, and
2080 protects these variables from casual modification by
2081 the user. Once set, these variables are read-only,
2082 and write or delete attempts are rejected. You can
2083 change this behaviour:
2085 If CONFIG_ENV_OVERWRITE is #defined in your config
2086 file, the write protection for vendor parameters is
2087 completely disabled. Anybody can change or delete
2090 Alternatively, if you #define _both_ CONFIG_ETHADDR
2091 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2092 Ethernet address is installed in the environment,
2093 which can be changed exactly ONCE by the user. [The
2094 serial# is unaffected by this, i. e. it remains
2100 Define this variable to enable the reservation of
2101 "protected RAM", i. e. RAM which is not overwritten
2102 by U-Boot. Define CONFIG_PRAM to hold the number of
2103 kB you want to reserve for pRAM. You can overwrite
2104 this default value by defining an environment
2105 variable "pram" to the number of kB you want to
2106 reserve. Note that the board info structure will
2107 still show the full amount of RAM. If pRAM is
2108 reserved, a new environment variable "mem" will
2109 automatically be defined to hold the amount of
2110 remaining RAM in a form that can be passed as boot
2111 argument to Linux, for instance like that:
2113 setenv bootargs ... mem=\${mem}
2116 This way you can tell Linux not to use this memory,
2117 either, which results in a memory region that will
2118 not be affected by reboots.
2120 *WARNING* If your board configuration uses automatic
2121 detection of the RAM size, you must make sure that
2122 this memory test is non-destructive. So far, the
2123 following board configurations are known to be
2126 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2127 HERMES, IP860, RPXlite, LWMON, LANTEC,
2133 Define this variable to stop the system in case of a
2134 fatal error, so that you have to reset it manually.
2135 This is probably NOT a good idea for an embedded
2136 system where you want the system to reboot
2137 automatically as fast as possible, but it may be
2138 useful during development since you can try to debug
2139 the conditions that lead to the situation.
2141 CONFIG_NET_RETRY_COUNT
2143 This variable defines the number of retries for
2144 network operations like ARP, RARP, TFTP, or BOOTP
2145 before giving up the operation. If not defined, a
2146 default value of 5 is used.
2150 Timeout waiting for an ARP reply in milliseconds.
2152 - Command Interpreter:
2153 CONFIG_AUTO_COMPLETE
2155 Enable auto completion of commands using TAB.
2157 Note that this feature has NOT been implemented yet
2158 for the "hush" shell.
2161 CONFIG_SYS_HUSH_PARSER
2163 Define this variable to enable the "hush" shell (from
2164 Busybox) as command line interpreter, thus enabling
2165 powerful command line syntax like
2166 if...then...else...fi conditionals or `&&' and '||'
2167 constructs ("shell scripts").
2169 If undefined, you get the old, much simpler behaviour
2170 with a somewhat smaller memory footprint.
2173 CONFIG_SYS_PROMPT_HUSH_PS2
2175 This defines the secondary prompt string, which is
2176 printed when the command interpreter needs more input
2177 to complete a command. Usually "> ".
2181 In the current implementation, the local variables
2182 space and global environment variables space are
2183 separated. Local variables are those you define by
2184 simply typing `name=value'. To access a local
2185 variable later on, you have write `$name' or
2186 `${name}'; to execute the contents of a variable
2187 directly type `$name' at the command prompt.
2189 Global environment variables are those you use
2190 setenv/printenv to work with. To run a command stored
2191 in such a variable, you need to use the run command,
2192 and you must not use the '$' sign to access them.
2194 To store commands and special characters in a
2195 variable, please use double quotation marks
2196 surrounding the whole text of the variable, instead
2197 of the backslashes before semicolons and special
2200 - Commandline Editing and History:
2201 CONFIG_CMDLINE_EDITING
2203 Enable editing and History functions for interactive
2204 commandline input operations
2206 - Default Environment:
2207 CONFIG_EXTRA_ENV_SETTINGS
2209 Define this to contain any number of null terminated
2210 strings (variable = value pairs) that will be part of
2211 the default environment compiled into the boot image.
2213 For example, place something like this in your
2214 board's config file:
2216 #define CONFIG_EXTRA_ENV_SETTINGS \
2220 Warning: This method is based on knowledge about the
2221 internal format how the environment is stored by the
2222 U-Boot code. This is NOT an official, exported
2223 interface! Although it is unlikely that this format
2224 will change soon, there is no guarantee either.
2225 You better know what you are doing here.
2227 Note: overly (ab)use of the default environment is
2228 discouraged. Make sure to check other ways to preset
2229 the environment like the "source" command or the
2232 - DataFlash Support:
2233 CONFIG_HAS_DATAFLASH
2235 Defining this option enables DataFlash features and
2236 allows to read/write in Dataflash via the standard
2239 - Serial Flash support
2242 Defining this option enables SPI flash commands
2243 'sf probe/read/write/erase/update'.
2245 Usage requires an initial 'probe' to define the serial
2246 flash parameters, followed by read/write/erase/update
2249 The following defaults may be provided by the platform
2250 to handle the common case when only a single serial
2251 flash is present on the system.
2253 CONFIG_SF_DEFAULT_BUS Bus identifier
2254 CONFIG_SF_DEFAULT_CS Chip-select
2255 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2256 CONFIG_SF_DEFAULT_SPEED in Hz
2258 - SystemACE Support:
2261 Adding this option adds support for Xilinx SystemACE
2262 chips attached via some sort of local bus. The address
2263 of the chip must also be defined in the
2264 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2266 #define CONFIG_SYSTEMACE
2267 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2269 When SystemACE support is added, the "ace" device type
2270 becomes available to the fat commands, i.e. fatls.
2272 - TFTP Fixed UDP Port:
2275 If this is defined, the environment variable tftpsrcp
2276 is used to supply the TFTP UDP source port value.
2277 If tftpsrcp isn't defined, the normal pseudo-random port
2278 number generator is used.
2280 Also, the environment variable tftpdstp is used to supply
2281 the TFTP UDP destination port value. If tftpdstp isn't
2282 defined, the normal port 69 is used.
2284 The purpose for tftpsrcp is to allow a TFTP server to
2285 blindly start the TFTP transfer using the pre-configured
2286 target IP address and UDP port. This has the effect of
2287 "punching through" the (Windows XP) firewall, allowing
2288 the remainder of the TFTP transfer to proceed normally.
2289 A better solution is to properly configure the firewall,
2290 but sometimes that is not allowed.
2292 - Show boot progress:
2293 CONFIG_SHOW_BOOT_PROGRESS
2295 Defining this option allows to add some board-
2296 specific code (calling a user-provided function
2297 "show_boot_progress(int)") that enables you to show
2298 the system's boot progress on some display (for
2299 example, some LED's) on your board. At the moment,
2300 the following checkpoints are implemented:
2302 - Detailed boot stage timing
2304 Define this option to get detailed timing of each stage
2305 of the boot process.
2307 CONFIG_BOOTSTAGE_USER_COUNT
2308 This is the number of available user bootstage records.
2309 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2310 a new ID will be allocated from this stash. If you exceed
2311 the limit, recording will stop.
2313 CONFIG_BOOTSTAGE_REPORT
2314 Define this to print a report before boot, similar to this:
2316 Timer summary in microseconds:
2319 3,575,678 3,575,678 board_init_f start
2320 3,575,695 17 arch_cpu_init A9
2321 3,575,777 82 arch_cpu_init done
2322 3,659,598 83,821 board_init_r start
2323 3,910,375 250,777 main_loop
2324 29,916,167 26,005,792 bootm_start
2325 30,361,327 445,160 start_kernel
2327 Legacy uImage format:
2330 1 common/cmd_bootm.c before attempting to boot an image
2331 -1 common/cmd_bootm.c Image header has bad magic number
2332 2 common/cmd_bootm.c Image header has correct magic number
2333 -2 common/cmd_bootm.c Image header has bad checksum
2334 3 common/cmd_bootm.c Image header has correct checksum
2335 -3 common/cmd_bootm.c Image data has bad checksum
2336 4 common/cmd_bootm.c Image data has correct checksum
2337 -4 common/cmd_bootm.c Image is for unsupported architecture
2338 5 common/cmd_bootm.c Architecture check OK
2339 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2340 6 common/cmd_bootm.c Image Type check OK
2341 -6 common/cmd_bootm.c gunzip uncompression error
2342 -7 common/cmd_bootm.c Unimplemented compression type
2343 7 common/cmd_bootm.c Uncompression OK
2344 8 common/cmd_bootm.c No uncompress/copy overwrite error
2345 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2347 9 common/image.c Start initial ramdisk verification
2348 -10 common/image.c Ramdisk header has bad magic number
2349 -11 common/image.c Ramdisk header has bad checksum
2350 10 common/image.c Ramdisk header is OK
2351 -12 common/image.c Ramdisk data has bad checksum
2352 11 common/image.c Ramdisk data has correct checksum
2353 12 common/image.c Ramdisk verification complete, start loading
2354 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2355 13 common/image.c Start multifile image verification
2356 14 common/image.c No initial ramdisk, no multifile, continue.
2358 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2360 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2361 -31 post/post.c POST test failed, detected by post_output_backlog()
2362 -32 post/post.c POST test failed, detected by post_run_single()
2364 34 common/cmd_doc.c before loading a Image from a DOC device
2365 -35 common/cmd_doc.c Bad usage of "doc" command
2366 35 common/cmd_doc.c correct usage of "doc" command
2367 -36 common/cmd_doc.c No boot device
2368 36 common/cmd_doc.c correct boot device
2369 -37 common/cmd_doc.c Unknown Chip ID on boot device
2370 37 common/cmd_doc.c correct chip ID found, device available
2371 -38 common/cmd_doc.c Read Error on boot device
2372 38 common/cmd_doc.c reading Image header from DOC device OK
2373 -39 common/cmd_doc.c Image header has bad magic number
2374 39 common/cmd_doc.c Image header has correct magic number
2375 -40 common/cmd_doc.c Error reading Image from DOC device
2376 40 common/cmd_doc.c Image header has correct magic number
2377 41 common/cmd_ide.c before loading a Image from a IDE device
2378 -42 common/cmd_ide.c Bad usage of "ide" command
2379 42 common/cmd_ide.c correct usage of "ide" command
2380 -43 common/cmd_ide.c No boot device
2381 43 common/cmd_ide.c boot device found
2382 -44 common/cmd_ide.c Device not available
2383 44 common/cmd_ide.c Device available
2384 -45 common/cmd_ide.c wrong partition selected
2385 45 common/cmd_ide.c partition selected
2386 -46 common/cmd_ide.c Unknown partition table
2387 46 common/cmd_ide.c valid partition table found
2388 -47 common/cmd_ide.c Invalid partition type
2389 47 common/cmd_ide.c correct partition type
2390 -48 common/cmd_ide.c Error reading Image Header on boot device
2391 48 common/cmd_ide.c reading Image Header from IDE device OK
2392 -49 common/cmd_ide.c Image header has bad magic number
2393 49 common/cmd_ide.c Image header has correct magic number
2394 -50 common/cmd_ide.c Image header has bad checksum
2395 50 common/cmd_ide.c Image header has correct checksum
2396 -51 common/cmd_ide.c Error reading Image from IDE device
2397 51 common/cmd_ide.c reading Image from IDE device OK
2398 52 common/cmd_nand.c before loading a Image from a NAND device
2399 -53 common/cmd_nand.c Bad usage of "nand" command
2400 53 common/cmd_nand.c correct usage of "nand" command
2401 -54 common/cmd_nand.c No boot device
2402 54 common/cmd_nand.c boot device found
2403 -55 common/cmd_nand.c Unknown Chip ID on boot device
2404 55 common/cmd_nand.c correct chip ID found, device available
2405 -56 common/cmd_nand.c Error reading Image Header on boot device
2406 56 common/cmd_nand.c reading Image Header from NAND device OK
2407 -57 common/cmd_nand.c Image header has bad magic number
2408 57 common/cmd_nand.c Image header has correct magic number
2409 -58 common/cmd_nand.c Error reading Image from NAND device
2410 58 common/cmd_nand.c reading Image from NAND device OK
2412 -60 common/env_common.c Environment has a bad CRC, using default
2414 64 net/eth.c starting with Ethernet configuration.
2415 -64 net/eth.c no Ethernet found.
2416 65 net/eth.c Ethernet found.
2418 -80 common/cmd_net.c usage wrong
2419 80 common/cmd_net.c before calling NetLoop()
2420 -81 common/cmd_net.c some error in NetLoop() occurred
2421 81 common/cmd_net.c NetLoop() back without error
2422 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2423 82 common/cmd_net.c trying automatic boot
2424 83 common/cmd_net.c running "source" command
2425 -83 common/cmd_net.c some error in automatic boot or "source" command
2426 84 common/cmd_net.c end without errors
2431 100 common/cmd_bootm.c Kernel FIT Image has correct format
2432 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2433 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2434 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2435 102 common/cmd_bootm.c Kernel unit name specified
2436 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2437 103 common/cmd_bootm.c Found configuration node
2438 104 common/cmd_bootm.c Got kernel subimage node offset
2439 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2440 105 common/cmd_bootm.c Kernel subimage hash verification OK
2441 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2442 106 common/cmd_bootm.c Architecture check OK
2443 -106 common/cmd_bootm.c Kernel subimage has wrong type
2444 107 common/cmd_bootm.c Kernel subimage type OK
2445 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2446 108 common/cmd_bootm.c Got kernel subimage data/size
2447 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2448 -109 common/cmd_bootm.c Can't get kernel subimage type
2449 -110 common/cmd_bootm.c Can't get kernel subimage comp
2450 -111 common/cmd_bootm.c Can't get kernel subimage os
2451 -112 common/cmd_bootm.c Can't get kernel subimage load address
2452 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2454 120 common/image.c Start initial ramdisk verification
2455 -120 common/image.c Ramdisk FIT image has incorrect format
2456 121 common/image.c Ramdisk FIT image has correct format
2457 122 common/image.c No ramdisk subimage unit name, using configuration
2458 -122 common/image.c Can't get configuration for ramdisk subimage
2459 123 common/image.c Ramdisk unit name specified
2460 -124 common/image.c Can't get ramdisk subimage node offset
2461 125 common/image.c Got ramdisk subimage node offset
2462 -125 common/image.c Ramdisk subimage hash verification failed
2463 126 common/image.c Ramdisk subimage hash verification OK
2464 -126 common/image.c Ramdisk subimage for unsupported architecture
2465 127 common/image.c Architecture check OK
2466 -127 common/image.c Can't get ramdisk subimage data/size
2467 128 common/image.c Got ramdisk subimage data/size
2468 129 common/image.c Can't get ramdisk load address
2469 -129 common/image.c Got ramdisk load address
2471 -130 common/cmd_doc.c Incorrect FIT image format
2472 131 common/cmd_doc.c FIT image format OK
2474 -140 common/cmd_ide.c Incorrect FIT image format
2475 141 common/cmd_ide.c FIT image format OK
2477 -150 common/cmd_nand.c Incorrect FIT image format
2478 151 common/cmd_nand.c FIT image format OK
2480 - Standalone program support:
2481 CONFIG_STANDALONE_LOAD_ADDR
2483 This option defines a board specific value for the
2484 address where standalone program gets loaded, thus
2485 overwriting the architecture dependent default
2488 - Frame Buffer Address:
2491 Define CONFIG_FB_ADDR if you want to use specific
2492 address for frame buffer.
2493 Then system will reserve the frame buffer address to
2494 defined address instead of lcd_setmem (this function
2495 grabs the memory for frame buffer by panel's size).
2497 Please see board_init_f function.
2499 - Automatic software updates via TFTP server
2501 CONFIG_UPDATE_TFTP_CNT_MAX
2502 CONFIG_UPDATE_TFTP_MSEC_MAX
2504 These options enable and control the auto-update feature;
2505 for a more detailed description refer to doc/README.update.
2507 - MTD Support (mtdparts command, UBI support)
2510 Adds the MTD device infrastructure from the Linux kernel.
2511 Needed for mtdparts command support.
2513 CONFIG_MTD_PARTITIONS
2515 Adds the MTD partitioning infrastructure from the Linux
2516 kernel. Needed for UBI support.
2520 Enable building of SPL globally.
2523 LDSCRIPT for linking the SPL binary.
2526 Maximum binary size (text, data and rodata) of the SPL binary.
2528 CONFIG_SPL_TEXT_BASE
2529 TEXT_BASE for linking the SPL binary.
2531 CONFIG_SPL_BSS_START_ADDR
2532 Link address for the BSS within the SPL binary.
2534 CONFIG_SPL_BSS_MAX_SIZE
2535 Maximum binary size of the BSS section of the SPL binary.
2538 Adress of the start of the stack SPL will use
2540 CONFIG_SYS_SPL_MALLOC_START
2541 Starting address of the malloc pool used in SPL.
2543 CONFIG_SYS_SPL_MALLOC_SIZE
2544 The size of the malloc pool used in SPL.
2546 CONFIG_SPL_LIBCOMMON_SUPPORT
2547 Support for common/libcommon.o in SPL binary
2549 CONFIG_SPL_LIBDISK_SUPPORT
2550 Support for disk/libdisk.o in SPL binary
2552 CONFIG_SPL_I2C_SUPPORT
2553 Support for drivers/i2c/libi2c.o in SPL binary
2555 CONFIG_SPL_GPIO_SUPPORT
2556 Support for drivers/gpio/libgpio.o in SPL binary
2558 CONFIG_SPL_MMC_SUPPORT
2559 Support for drivers/mmc/libmmc.o in SPL binary
2561 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
2562 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
2563 CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
2564 Address, size and partition on the MMC to load U-Boot from
2565 when the MMC is being used in raw mode.
2567 CONFIG_SPL_FAT_SUPPORT
2568 Support for fs/fat/libfat.o in SPL binary
2570 CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
2571 Filename to read to load U-Boot when reading from FAT
2573 CONFIG_SPL_NAND_SIMPLE
2574 Support for drivers/mtd/nand/libnand.o in SPL binary
2576 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2577 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2578 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2579 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2580 CONFIG_SYS_NAND_ECCBYTES
2581 Defines the size and behavior of the NAND that SPL uses
2582 to read U-Boot with CONFIG_SPL_NAND_SIMPLE
2584 CONFIG_SYS_NAND_U_BOOT_OFFS
2585 Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
2588 CONFIG_SYS_NAND_U_BOOT_START
2589 Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
2592 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2593 Define this if you need to first read the OOB and then the
2594 data. This is used for example on davinci plattforms.
2596 CONFIG_SPL_OMAP3_ID_NAND
2597 Support for an OMAP3-specific set of functions to return the
2598 ID and MFR of the first attached NAND chip, if present.
2600 CONFIG_SPL_SERIAL_SUPPORT
2601 Support for drivers/serial/libserial.o in SPL binary
2603 CONFIG_SPL_SPI_FLASH_SUPPORT
2604 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2606 CONFIG_SPL_SPI_SUPPORT
2607 Support for drivers/spi/libspi.o in SPL binary
2609 CONFIG_SPL_LIBGENERIC_SUPPORT
2610 Support for lib/libgeneric.o in SPL binary
2615 [so far only for SMDK2400 boards]
2617 - Modem support enable:
2618 CONFIG_MODEM_SUPPORT
2620 - RTS/CTS Flow control enable:
2623 - Modem debug support:
2624 CONFIG_MODEM_SUPPORT_DEBUG
2626 Enables debugging stuff (char screen[1024], dbg())
2627 for modem support. Useful only with BDI2000.
2629 - Interrupt support (PPC):
2631 There are common interrupt_init() and timer_interrupt()
2632 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2633 for CPU specific initialization. interrupt_init_cpu()
2634 should set decrementer_count to appropriate value. If
2635 CPU resets decrementer automatically after interrupt
2636 (ppc4xx) it should set decrementer_count to zero.
2637 timer_interrupt() calls timer_interrupt_cpu() for CPU
2638 specific handling. If board has watchdog / status_led
2639 / other_activity_monitor it works automatically from
2640 general timer_interrupt().
2644 In the target system modem support is enabled when a
2645 specific key (key combination) is pressed during
2646 power-on. Otherwise U-Boot will boot normally
2647 (autoboot). The key_pressed() function is called from
2648 board_init(). Currently key_pressed() is a dummy
2649 function, returning 1 and thus enabling modem
2652 If there are no modem init strings in the
2653 environment, U-Boot proceed to autoboot; the
2654 previous output (banner, info printfs) will be
2657 See also: doc/README.Modem
2659 Board initialization settings:
2660 ------------------------------
2662 During Initialization u-boot calls a number of board specific functions
2663 to allow the preparation of board specific prerequisites, e.g. pin setup
2664 before drivers are initialized. To enable these callbacks the
2665 following configuration macros have to be defined. Currently this is
2666 architecture specific, so please check arch/your_architecture/lib/board.c
2667 typically in board_init_f() and board_init_r().
2669 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2670 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2671 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2672 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2674 Configuration Settings:
2675 -----------------------
2677 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2678 undefine this when you're short of memory.
2680 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2681 width of the commands listed in the 'help' command output.
2683 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2684 prompt for user input.
2686 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2688 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2690 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2692 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2693 the application (usually a Linux kernel) when it is
2696 - CONFIG_SYS_BAUDRATE_TABLE:
2697 List of legal baudrate settings for this board.
2699 - CONFIG_SYS_CONSOLE_INFO_QUIET
2700 Suppress display of console information at boot.
2702 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2703 If the board specific function
2704 extern int overwrite_console (void);
2705 returns 1, the stdin, stderr and stdout are switched to the
2706 serial port, else the settings in the environment are used.
2708 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2709 Enable the call to overwrite_console().
2711 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2712 Enable overwrite of previous console environment settings.
2714 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2715 Begin and End addresses of the area used by the
2718 - CONFIG_SYS_ALT_MEMTEST:
2719 Enable an alternate, more extensive memory test.
2721 - CONFIG_SYS_MEMTEST_SCRATCH:
2722 Scratch address used by the alternate memory test
2723 You only need to set this if address zero isn't writeable
2725 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2726 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2727 this specified memory area will get subtracted from the top
2728 (end) of RAM and won't get "touched" at all by U-Boot. By
2729 fixing up gd->ram_size the Linux kernel should gets passed
2730 the now "corrected" memory size and won't touch it either.
2731 This should work for arch/ppc and arch/powerpc. Only Linux
2732 board ports in arch/powerpc with bootwrapper support that
2733 recalculate the memory size from the SDRAM controller setup
2734 will have to get fixed in Linux additionally.
2736 This option can be used as a workaround for the 440EPx/GRx
2737 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2740 WARNING: Please make sure that this value is a multiple of
2741 the Linux page size (normally 4k). If this is not the case,
2742 then the end address of the Linux memory will be located at a
2743 non page size aligned address and this could cause major
2746 - CONFIG_SYS_TFTP_LOADADDR:
2747 Default load address for network file downloads
2749 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2750 Enable temporary baudrate change while serial download
2752 - CONFIG_SYS_SDRAM_BASE:
2753 Physical start address of SDRAM. _Must_ be 0 here.
2755 - CONFIG_SYS_MBIO_BASE:
2756 Physical start address of Motherboard I/O (if using a
2759 - CONFIG_SYS_FLASH_BASE:
2760 Physical start address of Flash memory.
2762 - CONFIG_SYS_MONITOR_BASE:
2763 Physical start address of boot monitor code (set by
2764 make config files to be same as the text base address
2765 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2766 CONFIG_SYS_FLASH_BASE when booting from flash.
2768 - CONFIG_SYS_MONITOR_LEN:
2769 Size of memory reserved for monitor code, used to
2770 determine _at_compile_time_ (!) if the environment is
2771 embedded within the U-Boot image, or in a separate
2774 - CONFIG_SYS_MALLOC_LEN:
2775 Size of DRAM reserved for malloc() use.
2777 - CONFIG_SYS_BOOTM_LEN:
2778 Normally compressed uImages are limited to an
2779 uncompressed size of 8 MBytes. If this is not enough,
2780 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2781 to adjust this setting to your needs.
2783 - CONFIG_SYS_BOOTMAPSZ:
2784 Maximum size of memory mapped by the startup code of
2785 the Linux kernel; all data that must be processed by
2786 the Linux kernel (bd_info, boot arguments, FDT blob if
2787 used) must be put below this limit, unless "bootm_low"
2788 enviroment variable is defined and non-zero. In such case
2789 all data for the Linux kernel must be between "bootm_low"
2790 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2791 variable "bootm_mapsize" will override the value of
2792 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2793 then the value in "bootm_size" will be used instead.
2795 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2796 Enable initrd_high functionality. If defined then the
2797 initrd_high feature is enabled and the bootm ramdisk subcommand
2800 - CONFIG_SYS_BOOT_GET_CMDLINE:
2801 Enables allocating and saving kernel cmdline in space between
2802 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2804 - CONFIG_SYS_BOOT_GET_KBD:
2805 Enables allocating and saving a kernel copy of the bd_info in
2806 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2808 - CONFIG_SYS_MAX_FLASH_BANKS:
2809 Max number of Flash memory banks
2811 - CONFIG_SYS_MAX_FLASH_SECT:
2812 Max number of sectors on a Flash chip
2814 - CONFIG_SYS_FLASH_ERASE_TOUT:
2815 Timeout for Flash erase operations (in ms)
2817 - CONFIG_SYS_FLASH_WRITE_TOUT:
2818 Timeout for Flash write operations (in ms)
2820 - CONFIG_SYS_FLASH_LOCK_TOUT
2821 Timeout for Flash set sector lock bit operation (in ms)
2823 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2824 Timeout for Flash clear lock bits operation (in ms)
2826 - CONFIG_SYS_FLASH_PROTECTION
2827 If defined, hardware flash sectors protection is used
2828 instead of U-Boot software protection.
2830 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2832 Enable TFTP transfers directly to flash memory;
2833 without this option such a download has to be
2834 performed in two steps: (1) download to RAM, and (2)
2835 copy from RAM to flash.
2837 The two-step approach is usually more reliable, since
2838 you can check if the download worked before you erase
2839 the flash, but in some situations (when system RAM is
2840 too limited to allow for a temporary copy of the
2841 downloaded image) this option may be very useful.
2843 - CONFIG_SYS_FLASH_CFI:
2844 Define if the flash driver uses extra elements in the
2845 common flash structure for storing flash geometry.
2847 - CONFIG_FLASH_CFI_DRIVER
2848 This option also enables the building of the cfi_flash driver
2849 in the drivers directory
2851 - CONFIG_FLASH_CFI_MTD
2852 This option enables the building of the cfi_mtd driver
2853 in the drivers directory. The driver exports CFI flash
2856 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2857 Use buffered writes to flash.
2859 - CONFIG_FLASH_SPANSION_S29WS_N
2860 s29ws-n MirrorBit flash has non-standard addresses for buffered
2863 - CONFIG_SYS_FLASH_QUIET_TEST
2864 If this option is defined, the common CFI flash doesn't
2865 print it's warning upon not recognized FLASH banks. This
2866 is useful, if some of the configured banks are only
2867 optionally available.
2869 - CONFIG_FLASH_SHOW_PROGRESS
2870 If defined (must be an integer), print out countdown
2871 digits and dots. Recommended value: 45 (9..1) for 80
2872 column displays, 15 (3..1) for 40 column displays.
2874 - CONFIG_SYS_RX_ETH_BUFFER:
2875 Defines the number of Ethernet receive buffers. On some
2876 Ethernet controllers it is recommended to set this value
2877 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2878 buffers can be full shortly after enabling the interface
2879 on high Ethernet traffic.
2880 Defaults to 4 if not defined.
2882 - CONFIG_ENV_MAX_ENTRIES
2884 Maximum number of entries in the hash table that is used
2885 internally to store the environment settings. The default
2886 setting is supposed to be generous and should work in most
2887 cases. This setting can be used to tune behaviour; see
2888 lib/hashtable.c for details.
2890 The following definitions that deal with the placement and management
2891 of environment data (variable area); in general, we support the
2892 following configurations:
2894 - CONFIG_BUILD_ENVCRC:
2896 Builds up envcrc with the target environment so that external utils
2897 may easily extract it and embed it in final U-Boot images.
2899 - CONFIG_ENV_IS_IN_FLASH:
2901 Define this if the environment is in flash memory.
2903 a) The environment occupies one whole flash sector, which is
2904 "embedded" in the text segment with the U-Boot code. This
2905 happens usually with "bottom boot sector" or "top boot
2906 sector" type flash chips, which have several smaller
2907 sectors at the start or the end. For instance, such a
2908 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2909 such a case you would place the environment in one of the
2910 4 kB sectors - with U-Boot code before and after it. With
2911 "top boot sector" type flash chips, you would put the
2912 environment in one of the last sectors, leaving a gap
2913 between U-Boot and the environment.
2915 - CONFIG_ENV_OFFSET:
2917 Offset of environment data (variable area) to the
2918 beginning of flash memory; for instance, with bottom boot
2919 type flash chips the second sector can be used: the offset
2920 for this sector is given here.
2922 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2926 This is just another way to specify the start address of
2927 the flash sector containing the environment (instead of
2930 - CONFIG_ENV_SECT_SIZE:
2932 Size of the sector containing the environment.
2935 b) Sometimes flash chips have few, equal sized, BIG sectors.
2936 In such a case you don't want to spend a whole sector for
2941 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2942 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2943 of this flash sector for the environment. This saves
2944 memory for the RAM copy of the environment.
2946 It may also save flash memory if you decide to use this
2947 when your environment is "embedded" within U-Boot code,
2948 since then the remainder of the flash sector could be used
2949 for U-Boot code. It should be pointed out that this is
2950 STRONGLY DISCOURAGED from a robustness point of view:
2951 updating the environment in flash makes it always
2952 necessary to erase the WHOLE sector. If something goes
2953 wrong before the contents has been restored from a copy in
2954 RAM, your target system will be dead.
2956 - CONFIG_ENV_ADDR_REDUND
2957 CONFIG_ENV_SIZE_REDUND
2959 These settings describe a second storage area used to hold
2960 a redundant copy of the environment data, so that there is
2961 a valid backup copy in case there is a power failure during
2962 a "saveenv" operation.
2964 BE CAREFUL! Any changes to the flash layout, and some changes to the
2965 source code will make it necessary to adapt <board>/u-boot.lds*
2969 - CONFIG_ENV_IS_IN_NVRAM:
2971 Define this if you have some non-volatile memory device
2972 (NVRAM, battery buffered SRAM) which you want to use for the
2978 These two #defines are used to determine the memory area you
2979 want to use for environment. It is assumed that this memory
2980 can just be read and written to, without any special
2983 BE CAREFUL! The first access to the environment happens quite early
2984 in U-Boot initalization (when we try to get the setting of for the
2985 console baudrate). You *MUST* have mapped your NVRAM area then, or
2988 Please note that even with NVRAM we still use a copy of the
2989 environment in RAM: we could work on NVRAM directly, but we want to
2990 keep settings there always unmodified except somebody uses "saveenv"
2991 to save the current settings.
2994 - CONFIG_ENV_IS_IN_EEPROM:
2996 Use this if you have an EEPROM or similar serial access
2997 device and a driver for it.
2999 - CONFIG_ENV_OFFSET:
3002 These two #defines specify the offset and size of the
3003 environment area within the total memory of your EEPROM.
3005 - CONFIG_SYS_I2C_EEPROM_ADDR:
3006 If defined, specified the chip address of the EEPROM device.
3007 The default address is zero.
3009 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3010 If defined, the number of bits used to address bytes in a
3011 single page in the EEPROM device. A 64 byte page, for example
3012 would require six bits.
3014 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3015 If defined, the number of milliseconds to delay between
3016 page writes. The default is zero milliseconds.
3018 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3019 The length in bytes of the EEPROM memory array address. Note
3020 that this is NOT the chip address length!
3022 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3023 EEPROM chips that implement "address overflow" are ones
3024 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3025 address and the extra bits end up in the "chip address" bit
3026 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3029 Note that we consider the length of the address field to
3030 still be one byte because the extra address bits are hidden
3031 in the chip address.
3033 - CONFIG_SYS_EEPROM_SIZE:
3034 The size in bytes of the EEPROM device.
3036 - CONFIG_ENV_EEPROM_IS_ON_I2C
3037 define this, if you have I2C and SPI activated, and your
3038 EEPROM, which holds the environment, is on the I2C bus.
3040 - CONFIG_I2C_ENV_EEPROM_BUS
3041 if you have an Environment on an EEPROM reached over
3042 I2C muxes, you can define here, how to reach this
3043 EEPROM. For example:
3045 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
3047 EEPROM which holds the environment, is reached over
3048 a pca9547 i2c mux with address 0x70, channel 3.
3050 - CONFIG_ENV_IS_IN_DATAFLASH:
3052 Define this if you have a DataFlash memory device which you
3053 want to use for the environment.
3055 - CONFIG_ENV_OFFSET:
3059 These three #defines specify the offset and size of the
3060 environment area within the total memory of your DataFlash placed
3061 at the specified address.
3063 - CONFIG_ENV_IS_IN_REMOTE:
3065 Define this if you have a remote memory space which you
3066 want to use for the local device's environment.
3071 These two #defines specify the address and size of the
3072 environment area within the remote memory space. The
3073 local device can get the environment from remote memory
3074 space by SRIO or other links.
3076 BE CAREFUL! For some special cases, the local device can not use
3077 "saveenv" command. For example, the local device will get the
3078 environment stored in a remote NOR flash by SRIO link, but it can
3079 not erase, write this NOR flash by SRIO interface.
3081 - CONFIG_ENV_IS_IN_NAND:
3083 Define this if you have a NAND device which you want to use
3084 for the environment.
3086 - CONFIG_ENV_OFFSET:
3089 These two #defines specify the offset and size of the environment
3090 area within the first NAND device. CONFIG_ENV_OFFSET must be
3091 aligned to an erase block boundary.
3093 - CONFIG_ENV_OFFSET_REDUND (optional):
3095 This setting describes a second storage area of CONFIG_ENV_SIZE
3096 size used to hold a redundant copy of the environment data, so
3097 that there is a valid backup copy in case there is a power failure
3098 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
3099 aligned to an erase block boundary.
3101 - CONFIG_ENV_RANGE (optional):
3103 Specifies the length of the region in which the environment
3104 can be written. This should be a multiple of the NAND device's
3105 block size. Specifying a range with more erase blocks than
3106 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3107 the range to be avoided.
3109 - CONFIG_ENV_OFFSET_OOB (optional):
3111 Enables support for dynamically retrieving the offset of the
3112 environment from block zero's out-of-band data. The
3113 "nand env.oob" command can be used to record this offset.
3114 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3115 using CONFIG_ENV_OFFSET_OOB.
3117 - CONFIG_NAND_ENV_DST
3119 Defines address in RAM to which the nand_spl code should copy the
3120 environment. If redundant environment is used, it will be copied to
3121 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3123 - CONFIG_SYS_SPI_INIT_OFFSET
3125 Defines offset to the initial SPI buffer area in DPRAM. The
3126 area is used at an early stage (ROM part) if the environment
3127 is configured to reside in the SPI EEPROM: We need a 520 byte
3128 scratch DPRAM area. It is used between the two initialization
3129 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3130 to be a good choice since it makes it far enough from the
3131 start of the data area as well as from the stack pointer.
3133 Please note that the environment is read-only until the monitor
3134 has been relocated to RAM and a RAM copy of the environment has been
3135 created; also, when using EEPROM you will have to use getenv_f()
3136 until then to read environment variables.
3138 The environment is protected by a CRC32 checksum. Before the monitor
3139 is relocated into RAM, as a result of a bad CRC you will be working
3140 with the compiled-in default environment - *silently*!!! [This is
3141 necessary, because the first environment variable we need is the
3142 "baudrate" setting for the console - if we have a bad CRC, we don't
3143 have any device yet where we could complain.]
3145 Note: once the monitor has been relocated, then it will complain if
3146 the default environment is used; a new CRC is computed as soon as you
3147 use the "saveenv" command to store a valid environment.
3149 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3150 Echo the inverted Ethernet link state to the fault LED.
3152 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3153 also needs to be defined.
3155 - CONFIG_SYS_FAULT_MII_ADDR:
3156 MII address of the PHY to check for the Ethernet link state.
3158 - CONFIG_NS16550_MIN_FUNCTIONS:
3159 Define this if you desire to only have use of the NS16550_init
3160 and NS16550_putc functions for the serial driver located at
3161 drivers/serial/ns16550.c. This option is useful for saving
3162 space for already greatly restricted images, including but not
3163 limited to NAND_SPL configurations.
3165 Low Level (hardware related) configuration options:
3166 ---------------------------------------------------
3168 - CONFIG_SYS_CACHELINE_SIZE:
3169 Cache Line Size of the CPU.
3171 - CONFIG_SYS_DEFAULT_IMMR:
3172 Default address of the IMMR after system reset.
3174 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3175 and RPXsuper) to be able to adjust the position of
3176 the IMMR register after a reset.
3178 - CONFIG_SYS_CCSRBAR_DEFAULT:
3179 Default (power-on reset) physical address of CCSR on Freescale
3182 - CONFIG_SYS_CCSRBAR:
3183 Virtual address of CCSR. On a 32-bit build, this is typically
3184 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3186 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3187 for cross-platform code that uses that macro instead.
3189 - CONFIG_SYS_CCSRBAR_PHYS:
3190 Physical address of CCSR. CCSR can be relocated to a new
3191 physical address, if desired. In this case, this macro should
3192 be set to that address. Otherwise, it should be set to the
3193 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3194 is typically relocated on 36-bit builds. It is recommended
3195 that this macro be defined via the _HIGH and _LOW macros:
3197 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3198 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3200 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3201 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3202 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3203 used in assembly code, so it must not contain typecasts or
3204 integer size suffixes (e.g. "ULL").
3206 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3207 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3208 used in assembly code, so it must not contain typecasts or
3209 integer size suffixes (e.g. "ULL").
3211 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3212 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3213 forced to a value that ensures that CCSR is not relocated.
3215 - Floppy Disk Support:
3216 CONFIG_SYS_FDC_DRIVE_NUMBER
3218 the default drive number (default value 0)
3220 CONFIG_SYS_ISA_IO_STRIDE
3222 defines the spacing between FDC chipset registers
3225 CONFIG_SYS_ISA_IO_OFFSET
3227 defines the offset of register from address. It
3228 depends on which part of the data bus is connected to
3229 the FDC chipset. (default value 0)
3231 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3232 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3235 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3236 fdc_hw_init() is called at the beginning of the FDC
3237 setup. fdc_hw_init() must be provided by the board
3238 source code. It is used to make hardware dependant
3242 Most IDE controllers were designed to be connected with PCI
3243 interface. Only few of them were designed for AHB interface.
3244 When software is doing ATA command and data transfer to
3245 IDE devices through IDE-AHB controller, some additional
3246 registers accessing to these kind of IDE-AHB controller
3249 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3250 DO NOT CHANGE unless you know exactly what you're
3251 doing! (11-4) [MPC8xx/82xx systems only]
3253 - CONFIG_SYS_INIT_RAM_ADDR:
3255 Start address of memory area that can be used for
3256 initial data and stack; please note that this must be
3257 writable memory that is working WITHOUT special
3258 initialization, i. e. you CANNOT use normal RAM which
3259 will become available only after programming the
3260 memory controller and running certain initialization
3263 U-Boot uses the following memory types:
3264 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3265 - MPC824X: data cache
3266 - PPC4xx: data cache
3268 - CONFIG_SYS_GBL_DATA_OFFSET:
3270 Offset of the initial data structure in the memory
3271 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3272 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3273 data is located at the end of the available space
3274 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3275 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3276 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3277 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3280 On the MPC824X (or other systems that use the data
3281 cache for initial memory) the address chosen for
3282 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3283 point to an otherwise UNUSED address space between
3284 the top of RAM and the start of the PCI space.
3286 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3288 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3290 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3292 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3294 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3296 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3298 - CONFIG_SYS_OR_TIMING_SDRAM:
3301 - CONFIG_SYS_MAMR_PTA:
3302 periodic timer for refresh
3304 - CONFIG_SYS_DER: Debug Event Register (37-47)
3306 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3307 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3308 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3309 CONFIG_SYS_BR1_PRELIM:
3310 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3312 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3313 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3314 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3315 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3317 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3318 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3319 Machine Mode Register and Memory Periodic Timer
3320 Prescaler definitions (SDRAM timing)
3322 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3323 enable I2C microcode relocation patch (MPC8xx);
3324 define relocation offset in DPRAM [DSP2]
3326 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3327 enable SMC microcode relocation patch (MPC8xx);
3328 define relocation offset in DPRAM [SMC1]
3330 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3331 enable SPI microcode relocation patch (MPC8xx);
3332 define relocation offset in DPRAM [SCC4]
3334 - CONFIG_SYS_USE_OSCCLK:
3335 Use OSCM clock mode on MBX8xx board. Be careful,
3336 wrong setting might damage your board. Read
3337 doc/README.MBX before setting this variable!
3339 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3340 Offset of the bootmode word in DPRAM used by post
3341 (Power On Self Tests). This definition overrides
3342 #define'd default value in commproc.h resp.
3345 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3346 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3347 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3348 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3349 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3350 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3351 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3352 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3353 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3355 - CONFIG_PCI_DISABLE_PCIE:
3356 Disable PCI-Express on systems where it is supported but not
3360 Chip has SRIO or not
3363 Board has SRIO 1 port available
3366 Board has SRIO 2 port available
3368 - CONFIG_SYS_SRIOn_MEM_VIRT:
3369 Virtual Address of SRIO port 'n' memory region
3371 - CONFIG_SYS_SRIOn_MEM_PHYS:
3372 Physical Address of SRIO port 'n' memory region
3374 - CONFIG_SYS_SRIOn_MEM_SIZE:
3375 Size of SRIO port 'n' memory region
3377 - CONFIG_SYS_NDFC_16
3378 Defined to tell the NDFC that the NAND chip is using a
3381 - CONFIG_SYS_NDFC_EBC0_CFG
3382 Sets the EBC0_CFG register for the NDFC. If not defined
3383 a default value will be used.
3386 Get DDR timing information from an I2C EEPROM. Common
3387 with pluggable memory modules such as SODIMMs
3390 I2C address of the SPD EEPROM
3392 - CONFIG_SYS_SPD_BUS_NUM
3393 If SPD EEPROM is on an I2C bus other than the first
3394 one, specify here. Note that the value must resolve
3395 to something your driver can deal with.
3397 - CONFIG_SYS_DDR_RAW_TIMING
3398 Get DDR timing information from other than SPD. Common with
3399 soldered DDR chips onboard without SPD. DDR raw timing
3400 parameters are extracted from datasheet and hard-coded into
3401 header files or board specific files.
3403 - CONFIG_FSL_DDR_INTERACTIVE
3404 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3406 - CONFIG_SYS_83XX_DDR_USES_CS0
3407 Only for 83xx systems. If specified, then DDR should
3408 be configured using CS0 and CS1 instead of CS2 and CS3.
3410 - CONFIG_ETHER_ON_FEC[12]
3411 Define to enable FEC[12] on a 8xx series processor.
3413 - CONFIG_FEC[12]_PHY
3414 Define to the hardcoded PHY address which corresponds
3415 to the given FEC; i. e.
3416 #define CONFIG_FEC1_PHY 4
3417 means that the PHY with address 4 is connected to FEC1
3419 When set to -1, means to probe for first available.
3421 - CONFIG_FEC[12]_PHY_NORXERR
3422 The PHY does not have a RXERR line (RMII only).
3423 (so program the FEC to ignore it).
3426 Enable RMII mode for all FECs.
3427 Note that this is a global option, we can't
3428 have one FEC in standard MII mode and another in RMII mode.
3430 - CONFIG_CRC32_VERIFY
3431 Add a verify option to the crc32 command.
3434 => crc32 -v <address> <count> <crc32>
3436 Where address/count indicate a memory area
3437 and crc32 is the correct crc32 which the
3441 Add the "loopw" memory command. This only takes effect if
3442 the memory commands are activated globally (CONFIG_CMD_MEM).
3445 Add the "mdc" and "mwc" memory commands. These are cyclic
3450 This command will print 4 bytes (10,11,12,13) each 500 ms.
3452 => mwc.l 100 12345678 10
3453 This command will write 12345678 to address 100 all 10 ms.
3455 This only takes effect if the memory commands are activated
3456 globally (CONFIG_CMD_MEM).
3458 - CONFIG_SKIP_LOWLEVEL_INIT
3459 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3460 low level initializations (like setting up the memory
3461 controller) are omitted and/or U-Boot does not
3462 relocate itself into RAM.
3464 Normally this variable MUST NOT be defined. The only
3465 exception is when U-Boot is loaded (to RAM) by some
3466 other boot loader or by a debugger which performs
3467 these initializations itself.
3470 Modifies the behaviour of start.S when compiling a loader
3471 that is executed before the actual U-Boot. E.g. when
3472 compiling a NAND SPL.
3474 - CONFIG_USE_ARCH_MEMCPY
3475 CONFIG_USE_ARCH_MEMSET
3476 If these options are used a optimized version of memcpy/memset will
3477 be used if available. These functions may be faster under some
3478 conditions but may increase the binary size.
3480 Freescale QE/FMAN Firmware Support:
3481 -----------------------------------
3483 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3484 loading of "firmware", which is encoded in the QE firmware binary format.
3485 This firmware often needs to be loaded during U-Boot booting, so macros
3486 are used to identify the storage device (NOR flash, SPI, etc) and the address
3489 - CONFIG_SYS_QE_FMAN_FW_ADDR
3490 The address in the storage device where the firmware is located. The
3491 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3494 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3495 The maximum possible size of the firmware. The firmware binary format
3496 has a field that specifies the actual size of the firmware, but it
3497 might not be possible to read any part of the firmware unless some
3498 local storage is allocated to hold the entire firmware first.
3500 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3501 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3502 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3503 virtual address in NOR flash.
3505 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3506 Specifies that QE/FMAN firmware is located in NAND flash.
3507 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3509 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3510 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3511 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3513 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3514 Specifies that QE/FMAN firmware is located on the primary SPI
3515 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3517 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3518 Specifies that QE/FMAN firmware is located in the remote (master)
3519 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3520 can be mapped from slave TLB->slave LAW->slave SRIO outbound window
3521 ->master inbound window->master LAW->the ucode address in master's
3524 Building the Software:
3525 ======================
3527 Building U-Boot has been tested in several native build environments
3528 and in many different cross environments. Of course we cannot support
3529 all possibly existing versions of cross development tools in all
3530 (potentially obsolete) versions. In case of tool chain problems we
3531 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3532 which is extensively used to build and test U-Boot.
3534 If you are not using a native environment, it is assumed that you
3535 have GNU cross compiling tools available in your path. In this case,
3536 you must set the environment variable CROSS_COMPILE in your shell.
3537 Note that no changes to the Makefile or any other source files are
3538 necessary. For example using the ELDK on a 4xx CPU, please enter:
3540 $ CROSS_COMPILE=ppc_4xx-
3541 $ export CROSS_COMPILE
3543 Note: If you wish to generate Windows versions of the utilities in
3544 the tools directory you can use the MinGW toolchain
3545 (http://www.mingw.org). Set your HOST tools to the MinGW
3546 toolchain and execute 'make tools'. For example:
3548 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3550 Binaries such as tools/mkimage.exe will be created which can
3551 be executed on computers running Windows.
3553 U-Boot is intended to be simple to build. After installing the
3554 sources you must configure U-Boot for one specific board type. This
3559 where "NAME_config" is the name of one of the existing configu-
3560 rations; see boards.cfg for supported names.
3562 Note: for some board special configuration names may exist; check if
3563 additional information is available from the board vendor; for
3564 instance, the TQM823L systems are available without (standard)
3565 or with LCD support. You can select such additional "features"
3566 when choosing the configuration, i. e.
3569 - will configure for a plain TQM823L, i. e. no LCD support
3571 make TQM823L_LCD_config
3572 - will configure for a TQM823L with U-Boot console on LCD
3577 Finally, type "make all", and you should get some working U-Boot
3578 images ready for download to / installation on your system:
3580 - "u-boot.bin" is a raw binary image
3581 - "u-boot" is an image in ELF binary format
3582 - "u-boot.srec" is in Motorola S-Record format
3584 By default the build is performed locally and the objects are saved
3585 in the source directory. One of the two methods can be used to change
3586 this behavior and build U-Boot to some external directory:
3588 1. Add O= to the make command line invocations:
3590 make O=/tmp/build distclean
3591 make O=/tmp/build NAME_config
3592 make O=/tmp/build all
3594 2. Set environment variable BUILD_DIR to point to the desired location:
3596 export BUILD_DIR=/tmp/build
3601 Note that the command line "O=" setting overrides the BUILD_DIR environment
3605 Please be aware that the Makefiles assume you are using GNU make, so
3606 for instance on NetBSD you might need to use "gmake" instead of
3610 If the system board that you have is not listed, then you will need
3611 to port U-Boot to your hardware platform. To do this, follow these
3614 1. Add a new configuration option for your board to the toplevel
3615 "boards.cfg" file, using the existing entries as examples.
3616 Follow the instructions there to keep the boards in order.
3617 2. Create a new directory to hold your board specific code. Add any
3618 files you need. In your board directory, you will need at least
3619 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3620 3. Create a new configuration file "include/configs/<board>.h" for
3622 3. If you're porting U-Boot to a new CPU, then also create a new
3623 directory to hold your CPU specific code. Add any files you need.
3624 4. Run "make <board>_config" with your new name.
3625 5. Type "make", and you should get a working "u-boot.srec" file
3626 to be installed on your target system.
3627 6. Debug and solve any problems that might arise.
3628 [Of course, this last step is much harder than it sounds.]
3631 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3632 ==============================================================
3634 If you have modified U-Boot sources (for instance added a new board
3635 or support for new devices, a new CPU, etc.) you are expected to
3636 provide feedback to the other developers. The feedback normally takes
3637 the form of a "patch", i. e. a context diff against a certain (latest
3638 official or latest in the git repository) version of U-Boot sources.
3640 But before you submit such a patch, please verify that your modifi-
3641 cation did not break existing code. At least make sure that *ALL* of
3642 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3643 just run the "MAKEALL" script, which will configure and build U-Boot
3644 for ALL supported system. Be warned, this will take a while. You can
3645 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3646 environment variable to the script, i. e. to use the ELDK cross tools
3649 CROSS_COMPILE=ppc_8xx- MAKEALL
3651 or to build on a native PowerPC system you can type
3653 CROSS_COMPILE=' ' MAKEALL
3655 When using the MAKEALL script, the default behaviour is to build
3656 U-Boot in the source directory. This location can be changed by
3657 setting the BUILD_DIR environment variable. Also, for each target
3658 built, the MAKEALL script saves two log files (<target>.ERR and
3659 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3660 location can be changed by setting the MAKEALL_LOGDIR environment
3661 variable. For example:
3663 export BUILD_DIR=/tmp/build
3664 export MAKEALL_LOGDIR=/tmp/log
3665 CROSS_COMPILE=ppc_8xx- MAKEALL
3667 With the above settings build objects are saved in the /tmp/build,
3668 log files are saved in the /tmp/log and the source tree remains clean
3669 during the whole build process.
3672 See also "U-Boot Porting Guide" below.
3675 Monitor Commands - Overview:
3676 ============================
3678 go - start application at address 'addr'
3679 run - run commands in an environment variable
3680 bootm - boot application image from memory
3681 bootp - boot image via network using BootP/TFTP protocol
3682 bootz - boot zImage from memory
3683 tftpboot- boot image via network using TFTP protocol
3684 and env variables "ipaddr" and "serverip"
3685 (and eventually "gatewayip")
3686 tftpput - upload a file via network using TFTP protocol
3687 rarpboot- boot image via network using RARP/TFTP protocol
3688 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3689 loads - load S-Record file over serial line
3690 loadb - load binary file over serial line (kermit mode)
3692 mm - memory modify (auto-incrementing)
3693 nm - memory modify (constant address)
3694 mw - memory write (fill)
3696 cmp - memory compare
3697 crc32 - checksum calculation
3698 i2c - I2C sub-system
3699 sspi - SPI utility commands
3700 base - print or set address offset
3701 printenv- print environment variables
3702 setenv - set environment variables
3703 saveenv - save environment variables to persistent storage
3704 protect - enable or disable FLASH write protection
3705 erase - erase FLASH memory
3706 flinfo - print FLASH memory information
3707 bdinfo - print Board Info structure
3708 iminfo - print header information for application image
3709 coninfo - print console devices and informations
3710 ide - IDE sub-system
3711 loop - infinite loop on address range
3712 loopw - infinite write loop on address range
3713 mtest - simple RAM test
3714 icache - enable or disable instruction cache
3715 dcache - enable or disable data cache
3716 reset - Perform RESET of the CPU
3717 echo - echo args to console
3718 version - print monitor version
3719 help - print online help
3720 ? - alias for 'help'
3723 Monitor Commands - Detailed Description:
3724 ========================================
3728 For now: just type "help <command>".
3731 Environment Variables:
3732 ======================
3734 U-Boot supports user configuration using Environment Variables which
3735 can be made persistent by saving to Flash memory.
3737 Environment Variables are set using "setenv", printed using
3738 "printenv", and saved to Flash using "saveenv". Using "setenv"
3739 without a value can be used to delete a variable from the
3740 environment. As long as you don't save the environment you are
3741 working with an in-memory copy. In case the Flash area containing the
3742 environment is erased by accident, a default environment is provided.
3744 Some configuration options can be set using Environment Variables.
3746 List of environment variables (most likely not complete):
3748 baudrate - see CONFIG_BAUDRATE
3750 bootdelay - see CONFIG_BOOTDELAY
3752 bootcmd - see CONFIG_BOOTCOMMAND
3754 bootargs - Boot arguments when booting an RTOS image
3756 bootfile - Name of the image to load with TFTP
3758 bootm_low - Memory range available for image processing in the bootm
3759 command can be restricted. This variable is given as
3760 a hexadecimal number and defines lowest address allowed
3761 for use by the bootm command. See also "bootm_size"
3762 environment variable. Address defined by "bootm_low" is
3763 also the base of the initial memory mapping for the Linux
3764 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3767 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3768 This variable is given as a hexadecimal number and it
3769 defines the size of the memory region starting at base
3770 address bootm_low that is accessible by the Linux kernel
3771 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3772 as the default value if it is defined, and bootm_size is
3775 bootm_size - Memory range available for image processing in the bootm
3776 command can be restricted. This variable is given as
3777 a hexadecimal number and defines the size of the region
3778 allowed for use by the bootm command. See also "bootm_low"
3779 environment variable.
3781 updatefile - Location of the software update file on a TFTP server, used
3782 by the automatic software update feature. Please refer to
3783 documentation in doc/README.update for more details.
3785 autoload - if set to "no" (any string beginning with 'n'),
3786 "bootp" will just load perform a lookup of the
3787 configuration from the BOOTP server, but not try to
3788 load any image using TFTP
3790 autostart - if set to "yes", an image loaded using the "bootp",
3791 "rarpboot", "tftpboot" or "diskboot" commands will
3792 be automatically started (by internally calling
3795 If set to "no", a standalone image passed to the
3796 "bootm" command will be copied to the load address
3797 (and eventually uncompressed), but NOT be started.
3798 This can be used to load and uncompress arbitrary
3801 fdt_high - if set this restricts the maximum address that the
3802 flattened device tree will be copied into upon boot.
3803 For example, if you have a system with 1 GB memory
3804 at physical address 0x10000000, while Linux kernel
3805 only recognizes the first 704 MB as low memory, you
3806 may need to set fdt_high as 0x3C000000 to have the
3807 device tree blob be copied to the maximum address
3808 of the 704 MB low memory, so that Linux kernel can
3809 access it during the boot procedure.
3811 If this is set to the special value 0xFFFFFFFF then
3812 the fdt will not be copied at all on boot. For this
3813 to work it must reside in writable memory, have
3814 sufficient padding on the end of it for u-boot to
3815 add the information it needs into it, and the memory
3816 must be accessible by the kernel.
3818 fdtcontroladdr- if set this is the address of the control flattened
3819 device tree used by U-Boot when CONFIG_OF_CONTROL is
3822 i2cfast - (PPC405GP|PPC405EP only)
3823 if set to 'y' configures Linux I2C driver for fast
3824 mode (400kHZ). This environment variable is used in
3825 initialization code. So, for changes to be effective
3826 it must be saved and board must be reset.
3828 initrd_high - restrict positioning of initrd images:
3829 If this variable is not set, initrd images will be
3830 copied to the highest possible address in RAM; this
3831 is usually what you want since it allows for
3832 maximum initrd size. If for some reason you want to
3833 make sure that the initrd image is loaded below the
3834 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3835 variable to a value of "no" or "off" or "0".
3836 Alternatively, you can set it to a maximum upper
3837 address to use (U-Boot will still check that it
3838 does not overwrite the U-Boot stack and data).
3840 For instance, when you have a system with 16 MB
3841 RAM, and want to reserve 4 MB from use by Linux,
3842 you can do this by adding "mem=12M" to the value of
3843 the "bootargs" variable. However, now you must make
3844 sure that the initrd image is placed in the first
3845 12 MB as well - this can be done with
3847 setenv initrd_high 00c00000
3849 If you set initrd_high to 0xFFFFFFFF, this is an
3850 indication to U-Boot that all addresses are legal
3851 for the Linux kernel, including addresses in flash
3852 memory. In this case U-Boot will NOT COPY the
3853 ramdisk at all. This may be useful to reduce the
3854 boot time on your system, but requires that this
3855 feature is supported by your Linux kernel.
3857 ipaddr - IP address; needed for tftpboot command
3859 loadaddr - Default load address for commands like "bootp",
3860 "rarpboot", "tftpboot", "loadb" or "diskboot"
3862 loads_echo - see CONFIG_LOADS_ECHO
3864 serverip - TFTP server IP address; needed for tftpboot command
3866 bootretry - see CONFIG_BOOT_RETRY_TIME
3868 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3870 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3872 ethprime - controls which interface is used first.
3874 ethact - controls which interface is currently active.
3875 For example you can do the following
3877 => setenv ethact FEC
3878 => ping 192.168.0.1 # traffic sent on FEC
3879 => setenv ethact SCC
3880 => ping 10.0.0.1 # traffic sent on SCC
3882 ethrotate - When set to "no" U-Boot does not go through all
3883 available network interfaces.
3884 It just stays at the currently selected interface.
3886 netretry - When set to "no" each network operation will
3887 either succeed or fail without retrying.
3888 When set to "once" the network operation will
3889 fail when all the available network interfaces
3890 are tried once without success.
3891 Useful on scripts which control the retry operation
3894 npe_ucode - set load address for the NPE microcode
3896 tftpsrcport - If this is set, the value is used for TFTP's
3899 tftpdstport - If this is set, the value is used for TFTP's UDP
3900 destination port instead of the Well Know Port 69.
3902 tftpblocksize - Block size to use for TFTP transfers; if not set,
3903 we use the TFTP server's default block size
3905 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3906 seconds, minimum value is 1000 = 1 second). Defines
3907 when a packet is considered to be lost so it has to
3908 be retransmitted. The default is 5000 = 5 seconds.
3909 Lowering this value may make downloads succeed
3910 faster in networks with high packet loss rates or
3911 with unreliable TFTP servers.
3913 vlan - When set to a value < 4095 the traffic over
3914 Ethernet is encapsulated/received over 802.1q
3917 The following image location variables contain the location of images
3918 used in booting. The "Image" column gives the role of the image and is
3919 not an environment variable name. The other columns are environment
3920 variable names. "File Name" gives the name of the file on a TFTP
3921 server, "RAM Address" gives the location in RAM the image will be
3922 loaded to, and "Flash Location" gives the image's address in NOR
3923 flash or offset in NAND flash.
3925 *Note* - these variables don't have to be defined for all boards, some
3926 boards currenlty use other variables for these purposes, and some
3927 boards use these variables for other purposes.
3929 Image File Name RAM Address Flash Location
3930 ----- --------- ----------- --------------
3931 u-boot u-boot u-boot_addr_r u-boot_addr
3932 Linux kernel bootfile kernel_addr_r kernel_addr
3933 device tree blob fdtfile fdt_addr_r fdt_addr
3934 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3936 The following environment variables may be used and automatically
3937 updated by the network boot commands ("bootp" and "rarpboot"),
3938 depending the information provided by your boot server:
3940 bootfile - see above
3941 dnsip - IP address of your Domain Name Server
3942 dnsip2 - IP address of your secondary Domain Name Server
3943 gatewayip - IP address of the Gateway (Router) to use
3944 hostname - Target hostname
3946 netmask - Subnet Mask
3947 rootpath - Pathname of the root filesystem on the NFS server
3948 serverip - see above
3951 There are two special Environment Variables:
3953 serial# - contains hardware identification information such
3954 as type string and/or serial number
3955 ethaddr - Ethernet address
3957 These variables can be set only once (usually during manufacturing of
3958 the board). U-Boot refuses to delete or overwrite these variables
3959 once they have been set once.
3962 Further special Environment Variables:
3964 ver - Contains the U-Boot version string as printed
3965 with the "version" command. This variable is
3966 readonly (see CONFIG_VERSION_VARIABLE).
3969 Please note that changes to some configuration parameters may take
3970 only effect after the next boot (yes, that's just like Windoze :-).
3973 Command Line Parsing:
3974 =====================
3976 There are two different command line parsers available with U-Boot:
3977 the old "simple" one, and the much more powerful "hush" shell:
3979 Old, simple command line parser:
3980 --------------------------------
3982 - supports environment variables (through setenv / saveenv commands)
3983 - several commands on one line, separated by ';'
3984 - variable substitution using "... ${name} ..." syntax
3985 - special characters ('$', ';') can be escaped by prefixing with '\',
3987 setenv bootcmd bootm \${address}
3988 - You can also escape text by enclosing in single apostrophes, for example:
3989 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3994 - similar to Bourne shell, with control structures like
3995 if...then...else...fi, for...do...done; while...do...done,
3996 until...do...done, ...
3997 - supports environment ("global") variables (through setenv / saveenv
3998 commands) and local shell variables (through standard shell syntax
3999 "name=value"); only environment variables can be used with "run"
4005 (1) If a command line (or an environment variable executed by a "run"
4006 command) contains several commands separated by semicolon, and
4007 one of these commands fails, then the remaining commands will be
4010 (2) If you execute several variables with one call to run (i. e.
4011 calling run with a list of variables as arguments), any failing
4012 command will cause "run" to terminate, i. e. the remaining
4013 variables are not executed.
4015 Note for Redundant Ethernet Interfaces:
4016 =======================================
4018 Some boards come with redundant Ethernet interfaces; U-Boot supports
4019 such configurations and is capable of automatic selection of a
4020 "working" interface when needed. MAC assignment works as follows:
4022 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4023 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4024 "eth1addr" (=>eth1), "eth2addr", ...
4026 If the network interface stores some valid MAC address (for instance
4027 in SROM), this is used as default address if there is NO correspon-
4028 ding setting in the environment; if the corresponding environment
4029 variable is set, this overrides the settings in the card; that means:
4031 o If the SROM has a valid MAC address, and there is no address in the
4032 environment, the SROM's address is used.
4034 o If there is no valid address in the SROM, and a definition in the
4035 environment exists, then the value from the environment variable is
4038 o If both the SROM and the environment contain a MAC address, and
4039 both addresses are the same, this MAC address is used.
4041 o If both the SROM and the environment contain a MAC address, and the
4042 addresses differ, the value from the environment is used and a
4045 o If neither SROM nor the environment contain a MAC address, an error
4048 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4049 will be programmed into hardware as part of the initialization process. This
4050 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4051 The naming convention is as follows:
4052 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4057 U-Boot is capable of booting (and performing other auxiliary operations on)
4058 images in two formats:
4060 New uImage format (FIT)
4061 -----------------------
4063 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4064 to Flattened Device Tree). It allows the use of images with multiple
4065 components (several kernels, ramdisks, etc.), with contents protected by
4066 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4072 Old image format is based on binary files which can be basically anything,
4073 preceded by a special header; see the definitions in include/image.h for
4074 details; basically, the header defines the following image properties:
4076 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4077 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4078 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4079 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4081 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
4082 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4083 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4084 * Compression Type (uncompressed, gzip, bzip2)
4090 The header is marked by a special Magic Number, and both the header
4091 and the data portions of the image are secured against corruption by
4098 Although U-Boot should support any OS or standalone application
4099 easily, the main focus has always been on Linux during the design of
4102 U-Boot includes many features that so far have been part of some
4103 special "boot loader" code within the Linux kernel. Also, any
4104 "initrd" images to be used are no longer part of one big Linux image;
4105 instead, kernel and "initrd" are separate images. This implementation
4106 serves several purposes:
4108 - the same features can be used for other OS or standalone
4109 applications (for instance: using compressed images to reduce the
4110 Flash memory footprint)
4112 - it becomes much easier to port new Linux kernel versions because
4113 lots of low-level, hardware dependent stuff are done by U-Boot
4115 - the same Linux kernel image can now be used with different "initrd"
4116 images; of course this also means that different kernel images can
4117 be run with the same "initrd". This makes testing easier (you don't
4118 have to build a new "zImage.initrd" Linux image when you just
4119 change a file in your "initrd"). Also, a field-upgrade of the
4120 software is easier now.
4126 Porting Linux to U-Boot based systems:
4127 ---------------------------------------
4129 U-Boot cannot save you from doing all the necessary modifications to
4130 configure the Linux device drivers for use with your target hardware
4131 (no, we don't intend to provide a full virtual machine interface to
4134 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4136 Just make sure your machine specific header file (for instance
4137 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4138 Information structure as we define in include/asm-<arch>/u-boot.h,
4139 and make sure that your definition of IMAP_ADDR uses the same value
4140 as your U-Boot configuration in CONFIG_SYS_IMMR.
4143 Configuring the Linux kernel:
4144 -----------------------------
4146 No specific requirements for U-Boot. Make sure you have some root
4147 device (initial ramdisk, NFS) for your target system.
4150 Building a Linux Image:
4151 -----------------------
4153 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4154 not used. If you use recent kernel source, a new build target
4155 "uImage" will exist which automatically builds an image usable by
4156 U-Boot. Most older kernels also have support for a "pImage" target,
4157 which was introduced for our predecessor project PPCBoot and uses a
4158 100% compatible format.
4167 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4168 encapsulate a compressed Linux kernel image with header information,
4169 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4171 * build a standard "vmlinux" kernel image (in ELF binary format):
4173 * convert the kernel into a raw binary image:
4175 ${CROSS_COMPILE}-objcopy -O binary \
4176 -R .note -R .comment \
4177 -S vmlinux linux.bin
4179 * compress the binary image:
4183 * package compressed binary image for U-Boot:
4185 mkimage -A ppc -O linux -T kernel -C gzip \
4186 -a 0 -e 0 -n "Linux Kernel Image" \
4187 -d linux.bin.gz uImage
4190 The "mkimage" tool can also be used to create ramdisk images for use
4191 with U-Boot, either separated from the Linux kernel image, or
4192 combined into one file. "mkimage" encapsulates the images with a 64
4193 byte header containing information about target architecture,
4194 operating system, image type, compression method, entry points, time
4195 stamp, CRC32 checksums, etc.
4197 "mkimage" can be called in two ways: to verify existing images and
4198 print the header information, or to build new images.
4200 In the first form (with "-l" option) mkimage lists the information
4201 contained in the header of an existing U-Boot image; this includes
4202 checksum verification:
4204 tools/mkimage -l image
4205 -l ==> list image header information
4207 The second form (with "-d" option) is used to build a U-Boot image
4208 from a "data file" which is used as image payload:
4210 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4211 -n name -d data_file image
4212 -A ==> set architecture to 'arch'
4213 -O ==> set operating system to 'os'
4214 -T ==> set image type to 'type'
4215 -C ==> set compression type 'comp'
4216 -a ==> set load address to 'addr' (hex)
4217 -e ==> set entry point to 'ep' (hex)
4218 -n ==> set image name to 'name'
4219 -d ==> use image data from 'datafile'
4221 Right now, all Linux kernels for PowerPC systems use the same load
4222 address (0x00000000), but the entry point address depends on the
4225 - 2.2.x kernels have the entry point at 0x0000000C,
4226 - 2.3.x and later kernels have the entry point at 0x00000000.
4228 So a typical call to build a U-Boot image would read:
4230 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4231 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4232 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4233 > examples/uImage.TQM850L
4234 Image Name: 2.4.4 kernel for TQM850L
4235 Created: Wed Jul 19 02:34:59 2000
4236 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4237 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4238 Load Address: 0x00000000
4239 Entry Point: 0x00000000
4241 To verify the contents of the image (or check for corruption):
4243 -> tools/mkimage -l examples/uImage.TQM850L
4244 Image Name: 2.4.4 kernel for TQM850L
4245 Created: Wed Jul 19 02:34:59 2000
4246 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4247 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4248 Load Address: 0x00000000
4249 Entry Point: 0x00000000
4251 NOTE: for embedded systems where boot time is critical you can trade
4252 speed for memory and install an UNCOMPRESSED image instead: this
4253 needs more space in Flash, but boots much faster since it does not
4254 need to be uncompressed:
4256 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4257 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4258 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4259 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4260 > examples/uImage.TQM850L-uncompressed
4261 Image Name: 2.4.4 kernel for TQM850L
4262 Created: Wed Jul 19 02:34:59 2000
4263 Image Type: PowerPC Linux Kernel Image (uncompressed)
4264 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4265 Load Address: 0x00000000
4266 Entry Point: 0x00000000
4269 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4270 when your kernel is intended to use an initial ramdisk:
4272 -> tools/mkimage -n 'Simple Ramdisk Image' \
4273 > -A ppc -O linux -T ramdisk -C gzip \
4274 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4275 Image Name: Simple Ramdisk Image
4276 Created: Wed Jan 12 14:01:50 2000
4277 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4278 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4279 Load Address: 0x00000000
4280 Entry Point: 0x00000000
4283 Installing a Linux Image:
4284 -------------------------
4286 To downloading a U-Boot image over the serial (console) interface,
4287 you must convert the image to S-Record format:
4289 objcopy -I binary -O srec examples/image examples/image.srec
4291 The 'objcopy' does not understand the information in the U-Boot
4292 image header, so the resulting S-Record file will be relative to
4293 address 0x00000000. To load it to a given address, you need to
4294 specify the target address as 'offset' parameter with the 'loads'
4297 Example: install the image to address 0x40100000 (which on the
4298 TQM8xxL is in the first Flash bank):
4300 => erase 40100000 401FFFFF
4306 ## Ready for S-Record download ...
4307 ~>examples/image.srec
4308 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4310 15989 15990 15991 15992
4311 [file transfer complete]
4313 ## Start Addr = 0x00000000
4316 You can check the success of the download using the 'iminfo' command;
4317 this includes a checksum verification so you can be sure no data
4318 corruption happened:
4322 ## Checking Image at 40100000 ...
4323 Image Name: 2.2.13 for initrd on TQM850L
4324 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4325 Data Size: 335725 Bytes = 327 kB = 0 MB
4326 Load Address: 00000000
4327 Entry Point: 0000000c
4328 Verifying Checksum ... OK
4334 The "bootm" command is used to boot an application that is stored in
4335 memory (RAM or Flash). In case of a Linux kernel image, the contents
4336 of the "bootargs" environment variable is passed to the kernel as
4337 parameters. You can check and modify this variable using the
4338 "printenv" and "setenv" commands:
4341 => printenv bootargs
4342 bootargs=root=/dev/ram
4344 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4346 => printenv bootargs
4347 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4350 ## Booting Linux kernel at 40020000 ...
4351 Image Name: 2.2.13 for NFS on TQM850L
4352 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4353 Data Size: 381681 Bytes = 372 kB = 0 MB
4354 Load Address: 00000000
4355 Entry Point: 0000000c
4356 Verifying Checksum ... OK
4357 Uncompressing Kernel Image ... OK
4358 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
4359 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4360 time_init: decrementer frequency = 187500000/60
4361 Calibrating delay loop... 49.77 BogoMIPS
4362 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4365 If you want to boot a Linux kernel with initial RAM disk, you pass
4366 the memory addresses of both the kernel and the initrd image (PPBCOOT
4367 format!) to the "bootm" command:
4369 => imi 40100000 40200000
4371 ## Checking Image at 40100000 ...
4372 Image Name: 2.2.13 for initrd on TQM850L
4373 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4374 Data Size: 335725 Bytes = 327 kB = 0 MB
4375 Load Address: 00000000
4376 Entry Point: 0000000c
4377 Verifying Checksum ... OK
4379 ## Checking Image at 40200000 ...
4380 Image Name: Simple Ramdisk Image
4381 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4382 Data Size: 566530 Bytes = 553 kB = 0 MB
4383 Load Address: 00000000
4384 Entry Point: 00000000
4385 Verifying Checksum ... OK
4387 => bootm 40100000 40200000
4388 ## Booting Linux kernel at 40100000 ...
4389 Image Name: 2.2.13 for initrd on TQM850L
4390 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4391 Data Size: 335725 Bytes = 327 kB = 0 MB
4392 Load Address: 00000000
4393 Entry Point: 0000000c
4394 Verifying Checksum ... OK
4395 Uncompressing Kernel Image ... OK
4396 ## Loading RAMDisk Image at 40200000 ...
4397 Image Name: Simple Ramdisk Image
4398 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4399 Data Size: 566530 Bytes = 553 kB = 0 MB
4400 Load Address: 00000000
4401 Entry Point: 00000000
4402 Verifying Checksum ... OK
4403 Loading Ramdisk ... OK
4404 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
4405 Boot arguments: root=/dev/ram
4406 time_init: decrementer frequency = 187500000/60
4407 Calibrating delay loop... 49.77 BogoMIPS
4409 RAMDISK: Compressed image found at block 0
4410 VFS: Mounted root (ext2 filesystem).
4414 Boot Linux and pass a flat device tree:
4417 First, U-Boot must be compiled with the appropriate defines. See the section
4418 titled "Linux Kernel Interface" above for a more in depth explanation. The
4419 following is an example of how to start a kernel and pass an updated
4425 oft=oftrees/mpc8540ads.dtb
4426 => tftp $oftaddr $oft
4427 Speed: 1000, full duplex
4429 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4430 Filename 'oftrees/mpc8540ads.dtb'.
4431 Load address: 0x300000
4434 Bytes transferred = 4106 (100a hex)
4435 => tftp $loadaddr $bootfile
4436 Speed: 1000, full duplex
4438 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4440 Load address: 0x200000
4441 Loading:############
4443 Bytes transferred = 1029407 (fb51f hex)
4448 => bootm $loadaddr - $oftaddr
4449 ## Booting image at 00200000 ...
4450 Image Name: Linux-2.6.17-dirty
4451 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4452 Data Size: 1029343 Bytes = 1005.2 kB
4453 Load Address: 00000000
4454 Entry Point: 00000000
4455 Verifying Checksum ... OK
4456 Uncompressing Kernel Image ... OK
4457 Booting using flat device tree at 0x300000
4458 Using MPC85xx ADS machine description
4459 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4463 More About U-Boot Image Types:
4464 ------------------------------
4466 U-Boot supports the following image types:
4468 "Standalone Programs" are directly runnable in the environment
4469 provided by U-Boot; it is expected that (if they behave
4470 well) you can continue to work in U-Boot after return from
4471 the Standalone Program.
4472 "OS Kernel Images" are usually images of some Embedded OS which
4473 will take over control completely. Usually these programs
4474 will install their own set of exception handlers, device
4475 drivers, set up the MMU, etc. - this means, that you cannot
4476 expect to re-enter U-Boot except by resetting the CPU.
4477 "RAMDisk Images" are more or less just data blocks, and their
4478 parameters (address, size) are passed to an OS kernel that is
4480 "Multi-File Images" contain several images, typically an OS
4481 (Linux) kernel image and one or more data images like
4482 RAMDisks. This construct is useful for instance when you want
4483 to boot over the network using BOOTP etc., where the boot
4484 server provides just a single image file, but you want to get
4485 for instance an OS kernel and a RAMDisk image.
4487 "Multi-File Images" start with a list of image sizes, each
4488 image size (in bytes) specified by an "uint32_t" in network
4489 byte order. This list is terminated by an "(uint32_t)0".
4490 Immediately after the terminating 0 follow the images, one by
4491 one, all aligned on "uint32_t" boundaries (size rounded up to
4492 a multiple of 4 bytes).
4494 "Firmware Images" are binary images containing firmware (like
4495 U-Boot or FPGA images) which usually will be programmed to
4498 "Script files" are command sequences that will be executed by
4499 U-Boot's command interpreter; this feature is especially
4500 useful when you configure U-Boot to use a real shell (hush)
4501 as command interpreter.
4503 Booting the Linux zImage:
4504 -------------------------
4506 On some platforms, it's possible to boot Linux zImage. This is done
4507 using the "bootz" command. The syntax of "bootz" command is the same
4508 as the syntax of "bootm" command.
4510 Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
4511 kernel with raw initrd images. The syntax is slightly different, the
4512 address of the initrd must be augmented by it's size, in the following
4513 format: "<initrd addres>:<initrd size>".
4519 One of the features of U-Boot is that you can dynamically load and
4520 run "standalone" applications, which can use some resources of
4521 U-Boot like console I/O functions or interrupt services.
4523 Two simple examples are included with the sources:
4528 'examples/hello_world.c' contains a small "Hello World" Demo
4529 application; it is automatically compiled when you build U-Boot.
4530 It's configured to run at address 0x00040004, so you can play with it
4534 ## Ready for S-Record download ...
4535 ~>examples/hello_world.srec
4536 1 2 3 4 5 6 7 8 9 10 11 ...
4537 [file transfer complete]
4539 ## Start Addr = 0x00040004
4541 => go 40004 Hello World! This is a test.
4542 ## Starting application at 0x00040004 ...
4553 Hit any key to exit ...
4555 ## Application terminated, rc = 0x0
4557 Another example, which demonstrates how to register a CPM interrupt
4558 handler with the U-Boot code, can be found in 'examples/timer.c'.
4559 Here, a CPM timer is set up to generate an interrupt every second.
4560 The interrupt service routine is trivial, just printing a '.'
4561 character, but this is just a demo program. The application can be
4562 controlled by the following keys:
4564 ? - print current values og the CPM Timer registers
4565 b - enable interrupts and start timer
4566 e - stop timer and disable interrupts
4567 q - quit application
4570 ## Ready for S-Record download ...
4571 ~>examples/timer.srec
4572 1 2 3 4 5 6 7 8 9 10 11 ...
4573 [file transfer complete]
4575 ## Start Addr = 0x00040004
4578 ## Starting application at 0x00040004 ...
4581 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4584 [q, b, e, ?] Set interval 1000000 us
4587 [q, b, e, ?] ........
4588 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4591 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4594 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4597 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4599 [q, b, e, ?] ...Stopping timer
4601 [q, b, e, ?] ## Application terminated, rc = 0x0
4607 Over time, many people have reported problems when trying to use the
4608 "minicom" terminal emulation program for serial download. I (wd)
4609 consider minicom to be broken, and recommend not to use it. Under
4610 Unix, I recommend to use C-Kermit for general purpose use (and
4611 especially for kermit binary protocol download ("loadb" command), and
4612 use "cu" for S-Record download ("loads" command).
4614 Nevertheless, if you absolutely want to use it try adding this
4615 configuration to your "File transfer protocols" section:
4617 Name Program Name U/D FullScr IO-Red. Multi
4618 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4619 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4625 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4626 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4628 Building requires a cross environment; it is known to work on
4629 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4630 need gmake since the Makefiles are not compatible with BSD make).
4631 Note that the cross-powerpc package does not install include files;
4632 attempting to build U-Boot will fail because <machine/ansi.h> is
4633 missing. This file has to be installed and patched manually:
4635 # cd /usr/pkg/cross/powerpc-netbsd/include
4637 # ln -s powerpc machine
4638 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4639 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4641 Native builds *don't* work due to incompatibilities between native
4642 and U-Boot include files.
4644 Booting assumes that (the first part of) the image booted is a
4645 stage-2 loader which in turn loads and then invokes the kernel
4646 proper. Loader sources will eventually appear in the NetBSD source
4647 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4648 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4651 Implementation Internals:
4652 =========================
4654 The following is not intended to be a complete description of every
4655 implementation detail. However, it should help to understand the
4656 inner workings of U-Boot and make it easier to port it to custom
4660 Initial Stack, Global Data:
4661 ---------------------------
4663 The implementation of U-Boot is complicated by the fact that U-Boot
4664 starts running out of ROM (flash memory), usually without access to
4665 system RAM (because the memory controller is not initialized yet).
4666 This means that we don't have writable Data or BSS segments, and BSS
4667 is not initialized as zero. To be able to get a C environment working
4668 at all, we have to allocate at least a minimal stack. Implementation
4669 options for this are defined and restricted by the CPU used: Some CPU
4670 models provide on-chip memory (like the IMMR area on MPC8xx and
4671 MPC826x processors), on others (parts of) the data cache can be
4672 locked as (mis-) used as memory, etc.
4674 Chris Hallinan posted a good summary of these issues to the
4675 U-Boot mailing list:
4677 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4678 From: "Chris Hallinan" <clh@net1plus.com>
4679 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4682 Correct me if I'm wrong, folks, but the way I understand it
4683 is this: Using DCACHE as initial RAM for Stack, etc, does not
4684 require any physical RAM backing up the cache. The cleverness
4685 is that the cache is being used as a temporary supply of
4686 necessary storage before the SDRAM controller is setup. It's
4687 beyond the scope of this list to explain the details, but you
4688 can see how this works by studying the cache architecture and
4689 operation in the architecture and processor-specific manuals.
4691 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4692 is another option for the system designer to use as an
4693 initial stack/RAM area prior to SDRAM being available. Either
4694 option should work for you. Using CS 4 should be fine if your
4695 board designers haven't used it for something that would
4696 cause you grief during the initial boot! It is frequently not
4699 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4700 with your processor/board/system design. The default value
4701 you will find in any recent u-boot distribution in
4702 walnut.h should work for you. I'd set it to a value larger
4703 than your SDRAM module. If you have a 64MB SDRAM module, set
4704 it above 400_0000. Just make sure your board has no resources
4705 that are supposed to respond to that address! That code in
4706 start.S has been around a while and should work as is when
4707 you get the config right.
4712 It is essential to remember this, since it has some impact on the C
4713 code for the initialization procedures:
4715 * Initialized global data (data segment) is read-only. Do not attempt
4718 * Do not use any uninitialized global data (or implicitely initialized
4719 as zero data - BSS segment) at all - this is undefined, initiali-
4720 zation is performed later (when relocating to RAM).
4722 * Stack space is very limited. Avoid big data buffers or things like
4725 Having only the stack as writable memory limits means we cannot use
4726 normal global data to share information beween the code. But it
4727 turned out that the implementation of U-Boot can be greatly
4728 simplified by making a global data structure (gd_t) available to all
4729 functions. We could pass a pointer to this data as argument to _all_
4730 functions, but this would bloat the code. Instead we use a feature of
4731 the GCC compiler (Global Register Variables) to share the data: we
4732 place a pointer (gd) to the global data into a register which we
4733 reserve for this purpose.
4735 When choosing a register for such a purpose we are restricted by the
4736 relevant (E)ABI specifications for the current architecture, and by
4737 GCC's implementation.
4739 For PowerPC, the following registers have specific use:
4741 R2: reserved for system use
4742 R3-R4: parameter passing and return values
4743 R5-R10: parameter passing
4744 R13: small data area pointer
4748 (U-Boot also uses R12 as internal GOT pointer. r12
4749 is a volatile register so r12 needs to be reset when
4750 going back and forth between asm and C)
4752 ==> U-Boot will use R2 to hold a pointer to the global data
4754 Note: on PPC, we could use a static initializer (since the
4755 address of the global data structure is known at compile time),
4756 but it turned out that reserving a register results in somewhat
4757 smaller code - although the code savings are not that big (on
4758 average for all boards 752 bytes for the whole U-Boot image,
4759 624 text + 127 data).
4761 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4762 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4764 ==> U-Boot will use P3 to hold a pointer to the global data
4766 On ARM, the following registers are used:
4768 R0: function argument word/integer result
4769 R1-R3: function argument word
4771 R10: stack limit (used only if stack checking if enabled)
4772 R11: argument (frame) pointer
4773 R12: temporary workspace
4776 R15: program counter
4778 ==> U-Boot will use R8 to hold a pointer to the global data
4780 On Nios II, the ABI is documented here:
4781 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4783 ==> U-Boot will use gp to hold a pointer to the global data
4785 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4786 to access small data sections, so gp is free.
4788 On NDS32, the following registers are used:
4790 R0-R1: argument/return
4792 R15: temporary register for assembler
4793 R16: trampoline register
4794 R28: frame pointer (FP)
4795 R29: global pointer (GP)
4796 R30: link register (LP)
4797 R31: stack pointer (SP)
4798 PC: program counter (PC)
4800 ==> U-Boot will use R10 to hold a pointer to the global data
4802 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4803 or current versions of GCC may "optimize" the code too much.
4808 U-Boot runs in system state and uses physical addresses, i.e. the
4809 MMU is not used either for address mapping nor for memory protection.
4811 The available memory is mapped to fixed addresses using the memory
4812 controller. In this process, a contiguous block is formed for each
4813 memory type (Flash, SDRAM, SRAM), even when it consists of several
4814 physical memory banks.
4816 U-Boot is installed in the first 128 kB of the first Flash bank (on
4817 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4818 booting and sizing and initializing DRAM, the code relocates itself
4819 to the upper end of DRAM. Immediately below the U-Boot code some
4820 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4821 configuration setting]. Below that, a structure with global Board
4822 Info data is placed, followed by the stack (growing downward).
4824 Additionally, some exception handler code is copied to the low 8 kB
4825 of DRAM (0x00000000 ... 0x00001FFF).
4827 So a typical memory configuration with 16 MB of DRAM could look like
4830 0x0000 0000 Exception Vector code
4833 0x0000 2000 Free for Application Use
4839 0x00FB FF20 Monitor Stack (Growing downward)
4840 0x00FB FFAC Board Info Data and permanent copy of global data
4841 0x00FC 0000 Malloc Arena
4844 0x00FE 0000 RAM Copy of Monitor Code
4845 ... eventually: LCD or video framebuffer
4846 ... eventually: pRAM (Protected RAM - unchanged by reset)
4847 0x00FF FFFF [End of RAM]
4850 System Initialization:
4851 ----------------------
4853 In the reset configuration, U-Boot starts at the reset entry point
4854 (on most PowerPC systems at address 0x00000100). Because of the reset
4855 configuration for CS0# this is a mirror of the onboard Flash memory.
4856 To be able to re-map memory U-Boot then jumps to its link address.
4857 To be able to implement the initialization code in C, a (small!)
4858 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4859 which provide such a feature like MPC8xx or MPC8260), or in a locked
4860 part of the data cache. After that, U-Boot initializes the CPU core,
4861 the caches and the SIU.
4863 Next, all (potentially) available memory banks are mapped using a
4864 preliminary mapping. For example, we put them on 512 MB boundaries
4865 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4866 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4867 programmed for SDRAM access. Using the temporary configuration, a
4868 simple memory test is run that determines the size of the SDRAM
4871 When there is more than one SDRAM bank, and the banks are of
4872 different size, the largest is mapped first. For equal size, the first
4873 bank (CS2#) is mapped first. The first mapping is always for address
4874 0x00000000, with any additional banks following immediately to create
4875 contiguous memory starting from 0.
4877 Then, the monitor installs itself at the upper end of the SDRAM area
4878 and allocates memory for use by malloc() and for the global Board
4879 Info data; also, the exception vector code is copied to the low RAM
4880 pages, and the final stack is set up.
4882 Only after this relocation will you have a "normal" C environment;
4883 until that you are restricted in several ways, mostly because you are
4884 running from ROM, and because the code will have to be relocated to a
4888 U-Boot Porting Guide:
4889 ----------------------
4891 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4895 int main(int argc, char *argv[])
4897 sighandler_t no_more_time;
4899 signal(SIGALRM, no_more_time);
4900 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4902 if (available_money > available_manpower) {
4903 Pay consultant to port U-Boot;
4907 Download latest U-Boot source;
4909 Subscribe to u-boot mailing list;
4912 email("Hi, I am new to U-Boot, how do I get started?");
4915 Read the README file in the top level directory;
4916 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4917 Read applicable doc/*.README;
4918 Read the source, Luke;
4919 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4922 if (available_money > toLocalCurrency ($2500))
4925 Add a lot of aggravation and time;
4927 if (a similar board exists) { /* hopefully... */
4928 cp -a board/<similar> board/<myboard>
4929 cp include/configs/<similar>.h include/configs/<myboard>.h
4931 Create your own board support subdirectory;
4932 Create your own board include/configs/<myboard>.h file;
4934 Edit new board/<myboard> files
4935 Edit new include/configs/<myboard>.h
4940 Add / modify source code;
4944 email("Hi, I am having problems...");
4946 Send patch file to the U-Boot email list;
4947 if (reasonable critiques)
4948 Incorporate improvements from email list code review;
4950 Defend code as written;
4956 void no_more_time (int sig)
4965 All contributions to U-Boot should conform to the Linux kernel
4966 coding style; see the file "Documentation/CodingStyle" and the script
4967 "scripts/Lindent" in your Linux kernel source directory.
4969 Source files originating from a different project (for example the
4970 MTD subsystem) are generally exempt from these guidelines and are not
4971 reformated to ease subsequent migration to newer versions of those
4974 Please note that U-Boot is implemented in C (and to some small parts in
4975 Assembler); no C++ is used, so please do not use C++ style comments (//)
4978 Please also stick to the following formatting rules:
4979 - remove any trailing white space
4980 - use TAB characters for indentation and vertical alignment, not spaces
4981 - make sure NOT to use DOS '\r\n' line feeds
4982 - do not add more than 2 consecutive empty lines to source files
4983 - do not add trailing empty lines to source files
4985 Submissions which do not conform to the standards may be returned
4986 with a request to reformat the changes.
4992 Since the number of patches for U-Boot is growing, we need to
4993 establish some rules. Submissions which do not conform to these rules
4994 may be rejected, even when they contain important and valuable stuff.
4996 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4998 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4999 see http://lists.denx.de/mailman/listinfo/u-boot
5001 When you send a patch, please include the following information with
5004 * For bug fixes: a description of the bug and how your patch fixes
5005 this bug. Please try to include a way of demonstrating that the
5006 patch actually fixes something.
5008 * For new features: a description of the feature and your
5011 * A CHANGELOG entry as plaintext (separate from the patch)
5013 * For major contributions, your entry to the CREDITS file
5015 * When you add support for a new board, don't forget to add this
5016 board to the MAINTAINERS file, too.
5018 * If your patch adds new configuration options, don't forget to
5019 document these in the README file.
5021 * The patch itself. If you are using git (which is *strongly*
5022 recommended) you can easily generate the patch using the
5023 "git format-patch". If you then use "git send-email" to send it to
5024 the U-Boot mailing list, you will avoid most of the common problems
5025 with some other mail clients.
5027 If you cannot use git, use "diff -purN OLD NEW". If your version of
5028 diff does not support these options, then get the latest version of
5031 The current directory when running this command shall be the parent
5032 directory of the U-Boot source tree (i. e. please make sure that
5033 your patch includes sufficient directory information for the
5036 We prefer patches as plain text. MIME attachments are discouraged,
5037 and compressed attachments must not be used.
5039 * If one logical set of modifications affects or creates several
5040 files, all these changes shall be submitted in a SINGLE patch file.
5042 * Changesets that contain different, unrelated modifications shall be
5043 submitted as SEPARATE patches, one patch per changeset.
5048 * Before sending the patch, run the MAKEALL script on your patched
5049 source tree and make sure that no errors or warnings are reported
5050 for any of the boards.
5052 * Keep your modifications to the necessary minimum: A patch
5053 containing several unrelated changes or arbitrary reformats will be
5054 returned with a request to re-formatting / split it.
5056 * If you modify existing code, make sure that your new code does not
5057 add to the memory footprint of the code ;-) Small is beautiful!
5058 When adding new features, these should compile conditionally only
5059 (using #ifdef), and the resulting code with the new feature
5060 disabled must not need more memory than the old code without your
5063 * Remember that there is a size limit of 100 kB per message on the
5064 u-boot mailing list. Bigger patches will be moderated. If they are
5065 reasonable and not too big, they will be acknowledged. But patches
5066 bigger than the size limit should be avoided.