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 - Intel Monahans options:
378 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
380 Defines the Monahans run mode to oscillator
381 ratio. Valid values are 8, 16, 24, 31. The core
382 frequency is this value multiplied by 13 MHz.
384 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
386 Defines the Monahans turbo mode to oscillator
387 ratio. Valid values are 1 (default if undefined) and
388 2. The core frequency as calculated above is multiplied
392 CONFIG_SYS_INIT_SP_OFFSET
394 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
395 pointer. This is needed for the temporary stack before
398 CONFIG_SYS_MIPS_CACHE_MODE
400 Cache operation mode for the MIPS CPU.
401 See also arch/mips/include/asm/mipsregs.h.
403 CONF_CM_CACHABLE_NO_WA
406 CONF_CM_CACHABLE_NONCOHERENT
410 CONF_CM_CACHABLE_ACCELERATED
412 CONFIG_SYS_XWAY_EBU_BOOTCFG
414 Special option for Lantiq XWAY SoCs for booting from NOR flash.
415 See also arch/mips/cpu/mips32/start.S.
417 CONFIG_XWAY_SWAP_BYTES
419 Enable compilation of tools/xway-swap-bytes needed for Lantiq
420 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
421 be swapped if a flash programmer is used.
424 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
426 Select high exception vectors of the ARM core, e.g., do not
427 clear the V bit of the c1 register of CP15.
429 - Linux Kernel Interface:
432 U-Boot stores all clock information in Hz
433 internally. For binary compatibility with older Linux
434 kernels (which expect the clocks passed in the
435 bd_info data to be in MHz) the environment variable
436 "clocks_in_mhz" can be defined so that U-Boot
437 converts clock data to MHZ before passing it to the
439 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
440 "clocks_in_mhz=1" is automatically included in the
443 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
445 When transferring memsize parameter to linux, some versions
446 expect it to be in bytes, others in MB.
447 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
451 New kernel versions are expecting firmware settings to be
452 passed using flattened device trees (based on open firmware
456 * New libfdt-based support
457 * Adds the "fdt" command
458 * The bootm command automatically updates the fdt
460 OF_CPU - The proper name of the cpus node (only required for
461 MPC512X and MPC5xxx based boards).
462 OF_SOC - The proper name of the soc node (only required for
463 MPC512X and MPC5xxx based boards).
464 OF_TBCLK - The timebase frequency.
465 OF_STDOUT_PATH - The path to the console device
467 boards with QUICC Engines require OF_QE to set UCC MAC
470 CONFIG_OF_BOARD_SETUP
472 Board code has addition modification that it wants to make
473 to the flat device tree before handing it off to the kernel
477 This define fills in the correct boot CPU in the boot
478 param header, the default value is zero if undefined.
482 U-Boot can detect if an IDE device is present or not.
483 If not, and this new config option is activated, U-Boot
484 removes the ATA node from the DTS before booting Linux,
485 so the Linux IDE driver does not probe the device and
486 crash. This is needed for buggy hardware (uc101) where
487 no pull down resistor is connected to the signal IDE5V_DD7.
489 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
491 This setting is mandatory for all boards that have only one
492 machine type and must be used to specify the machine type
493 number as it appears in the ARM machine registry
494 (see http://www.arm.linux.org.uk/developer/machines/).
495 Only boards that have multiple machine types supported
496 in a single configuration file and the machine type is
497 runtime discoverable, do not have to use this setting.
499 - vxWorks boot parameters:
501 bootvx constructs a valid bootline using the following
502 environments variables: bootfile, ipaddr, serverip, hostname.
503 It loads the vxWorks image pointed bootfile.
505 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
506 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
507 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
508 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
510 CONFIG_SYS_VXWORKS_ADD_PARAMS
512 Add it at the end of the bootline. E.g "u=username pw=secret"
514 Note: If a "bootargs" environment is defined, it will overwride
515 the defaults discussed just above.
517 - Cache Configuration:
518 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
519 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
520 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
522 - Cache Configuration for ARM:
523 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
525 CONFIG_SYS_PL310_BASE - Physical base address of PL310
526 controller register space
531 Define this if you want support for Amba PrimeCell PL010 UARTs.
535 Define this if you want support for Amba PrimeCell PL011 UARTs.
539 If you have Amba PrimeCell PL011 UARTs, set this variable to
540 the clock speed of the UARTs.
544 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
545 define this to a list of base addresses for each (supported)
546 port. See e.g. include/configs/versatile.h
548 CONFIG_PL011_SERIAL_RLCR
550 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
551 have separate receive and transmit line control registers. Set
552 this variable to initialize the extra register.
554 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
556 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
557 boot loader that has already initialized the UART. Define this
558 variable to flush the UART at init time.
562 Depending on board, define exactly one serial port
563 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
564 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
565 console by defining CONFIG_8xx_CONS_NONE
567 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
568 port routines must be defined elsewhere
569 (i.e. serial_init(), serial_getc(), ...)
572 Enables console device for a color framebuffer. Needs following
573 defines (cf. smiLynxEM, i8042)
574 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
576 VIDEO_HW_RECTFILL graphic chip supports
579 VIDEO_HW_BITBLT graphic chip supports
580 bit-blit (cf. smiLynxEM)
581 VIDEO_VISIBLE_COLS visible pixel columns
583 VIDEO_VISIBLE_ROWS visible pixel rows
584 VIDEO_PIXEL_SIZE bytes per pixel
585 VIDEO_DATA_FORMAT graphic data format
586 (0-5, cf. cfb_console.c)
587 VIDEO_FB_ADRS framebuffer address
588 VIDEO_KBD_INIT_FCT keyboard int fct
589 (i.e. i8042_kbd_init())
590 VIDEO_TSTC_FCT test char fct
592 VIDEO_GETC_FCT get char fct
594 CONFIG_CONSOLE_CURSOR cursor drawing on/off
595 (requires blink timer
597 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
598 CONFIG_CONSOLE_TIME display time/date info in
600 (requires CONFIG_CMD_DATE)
601 CONFIG_VIDEO_LOGO display Linux logo in
603 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
604 linux_logo.h for logo.
605 Requires CONFIG_VIDEO_LOGO
606 CONFIG_CONSOLE_EXTRA_INFO
607 additional board info beside
610 When CONFIG_CFB_CONSOLE is defined, video console is
611 default i/o. Serial console can be forced with
612 environment 'console=serial'.
614 When CONFIG_SILENT_CONSOLE is defined, all console
615 messages (by U-Boot and Linux!) can be silenced with
616 the "silent" environment variable. See
617 doc/README.silent for more information.
620 CONFIG_BAUDRATE - in bps
621 Select one of the baudrates listed in
622 CONFIG_SYS_BAUDRATE_TABLE, see below.
623 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
625 - Console Rx buffer length
626 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
627 the maximum receive buffer length for the SMC.
628 This option is actual only for 82xx and 8xx possible.
629 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
630 must be defined, to setup the maximum idle timeout for
633 - Pre-Console Buffer:
634 Prior to the console being initialised (i.e. serial UART
635 initialised etc) all console output is silently discarded.
636 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
637 buffer any console messages prior to the console being
638 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
639 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
640 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
641 bytes are output before the console is initialised, the
642 earlier bytes are discarded.
644 'Sane' compilers will generate smaller code if
645 CONFIG_PRE_CON_BUF_SZ is a power of 2
647 - Pre-console putc():
648 Prior to the console being initialised, console output is
649 normally silently discarded. This can be annoying if a
650 panic() happens in this time.
652 If the CONFIG_PRE_CONSOLE_PUTC option is defined, then
653 U-Boot will call board_pre_console_putc() for each output
654 character in this case, This function should try to output
655 the character if possible, perhaps on all available UARTs
656 (it will need to do this directly, since the console code
657 is not functional yet). Note that if the panic happens
658 early enough, then it is possible that board_init_f()
659 (or even arch_cpu_init() on ARM) has not been called yet.
660 You should init all clocks, GPIOs, etc. that are needed
661 to get the character out. Baud rates will need to default
662 to something sensible.
664 - Safe printf() functions
665 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
666 the printf() functions. These are defined in
667 include/vsprintf.h and include snprintf(), vsnprintf() and
668 so on. Code size increase is approximately 300-500 bytes.
669 If this option is not given then these functions will
670 silently discard their buffer size argument - this means
671 you are not getting any overflow checking in this case.
673 - Boot Delay: CONFIG_BOOTDELAY - in seconds
674 Delay before automatically booting the default image;
675 set to -1 to disable autoboot.
677 See doc/README.autoboot for these options that
678 work with CONFIG_BOOTDELAY. None are required.
679 CONFIG_BOOT_RETRY_TIME
680 CONFIG_BOOT_RETRY_MIN
681 CONFIG_AUTOBOOT_KEYED
682 CONFIG_AUTOBOOT_PROMPT
683 CONFIG_AUTOBOOT_DELAY_STR
684 CONFIG_AUTOBOOT_STOP_STR
685 CONFIG_AUTOBOOT_DELAY_STR2
686 CONFIG_AUTOBOOT_STOP_STR2
687 CONFIG_ZERO_BOOTDELAY_CHECK
688 CONFIG_RESET_TO_RETRY
692 Only needed when CONFIG_BOOTDELAY is enabled;
693 define a command string that is automatically executed
694 when no character is read on the console interface
695 within "Boot Delay" after reset.
698 This can be used to pass arguments to the bootm
699 command. The value of CONFIG_BOOTARGS goes into the
700 environment value "bootargs".
702 CONFIG_RAMBOOT and CONFIG_NFSBOOT
703 The value of these goes into the environment as
704 "ramboot" and "nfsboot" respectively, and can be used
705 as a convenience, when switching between booting from
711 When this option is #defined, the existence of the
712 environment variable "preboot" will be checked
713 immediately before starting the CONFIG_BOOTDELAY
714 countdown and/or running the auto-boot command resp.
715 entering interactive mode.
717 This feature is especially useful when "preboot" is
718 automatically generated or modified. For an example
719 see the LWMON board specific code: here "preboot" is
720 modified when the user holds down a certain
721 combination of keys on the (special) keyboard when
724 - Serial Download Echo Mode:
726 If defined to 1, all characters received during a
727 serial download (using the "loads" command) are
728 echoed back. This might be needed by some terminal
729 emulations (like "cu"), but may as well just take
730 time on others. This setting #define's the initial
731 value of the "loads_echo" environment variable.
733 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
735 Select one of the baudrates listed in
736 CONFIG_SYS_BAUDRATE_TABLE, see below.
739 Monitor commands can be included or excluded
740 from the build by using the #include files
741 "config_cmd_all.h" and #undef'ing unwanted
742 commands, or using "config_cmd_default.h"
743 and augmenting with additional #define's
746 The default command configuration includes all commands
747 except those marked below with a "*".
749 CONFIG_CMD_ASKENV * ask for env variable
750 CONFIG_CMD_BDI bdinfo
751 CONFIG_CMD_BEDBUG * Include BedBug Debugger
752 CONFIG_CMD_BMP * BMP support
753 CONFIG_CMD_BSP * Board specific commands
754 CONFIG_CMD_BOOTD bootd
755 CONFIG_CMD_CACHE * icache, dcache
756 CONFIG_CMD_CONSOLE coninfo
757 CONFIG_CMD_CRC32 * crc32
758 CONFIG_CMD_DATE * support for RTC, date/time...
759 CONFIG_CMD_DHCP * DHCP support
760 CONFIG_CMD_DIAG * Diagnostics
761 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
762 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
763 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
764 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
765 CONFIG_CMD_DTT * Digital Therm and Thermostat
766 CONFIG_CMD_ECHO echo arguments
767 CONFIG_CMD_EDITENV edit env variable
768 CONFIG_CMD_EEPROM * EEPROM read/write support
769 CONFIG_CMD_ELF * bootelf, bootvx
770 CONFIG_CMD_EXPORTENV * export the environment
771 CONFIG_CMD_SAVEENV saveenv
772 CONFIG_CMD_FDC * Floppy Disk Support
773 CONFIG_CMD_FAT * FAT partition support
774 CONFIG_CMD_FDOS * Dos diskette Support
775 CONFIG_CMD_FLASH flinfo, erase, protect
776 CONFIG_CMD_FPGA FPGA device initialization support
777 CONFIG_CMD_GO * the 'go' command (exec code)
778 CONFIG_CMD_GREPENV * search environment
779 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
780 CONFIG_CMD_I2C * I2C serial bus support
781 CONFIG_CMD_IDE * IDE harddisk support
782 CONFIG_CMD_IMI iminfo
783 CONFIG_CMD_IMLS List all found images
784 CONFIG_CMD_IMMAP * IMMR dump support
785 CONFIG_CMD_IMPORTENV * import an environment
786 CONFIG_CMD_IRQ * irqinfo
787 CONFIG_CMD_ITEST Integer/string test of 2 values
788 CONFIG_CMD_JFFS2 * JFFS2 Support
789 CONFIG_CMD_KGDB * kgdb
790 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
791 CONFIG_CMD_LOADB loadb
792 CONFIG_CMD_LOADS loads
793 CONFIG_CMD_MD5SUM print md5 message digest
794 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
795 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
797 CONFIG_CMD_MISC Misc functions like sleep etc
798 CONFIG_CMD_MMC * MMC memory mapped support
799 CONFIG_CMD_MII * MII utility commands
800 CONFIG_CMD_MTDPARTS * MTD partition support
801 CONFIG_CMD_NAND * NAND support
802 CONFIG_CMD_NET bootp, tftpboot, rarpboot
803 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
804 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
805 CONFIG_CMD_PCI * pciinfo
806 CONFIG_CMD_PCMCIA * PCMCIA support
807 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
809 CONFIG_CMD_PORTIO * Port I/O
810 CONFIG_CMD_REGINFO * Register dump
811 CONFIG_CMD_RUN run command in env variable
812 CONFIG_CMD_SAVES * save S record dump
813 CONFIG_CMD_SCSI * SCSI Support
814 CONFIG_CMD_SDRAM * print SDRAM configuration information
815 (requires CONFIG_CMD_I2C)
816 CONFIG_CMD_SETGETDCR Support for DCR Register access
818 CONFIG_CMD_SHA1SUM print sha1 memory digest
819 (requires CONFIG_CMD_MEMORY)
820 CONFIG_CMD_SOURCE "source" command Support
821 CONFIG_CMD_SPI * SPI serial bus support
822 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
823 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
824 CONFIG_CMD_TIME * run command and report execution time
825 CONFIG_CMD_USB * USB support
826 CONFIG_CMD_CDP * Cisco Discover Protocol support
827 CONFIG_CMD_FSL * Microblaze FSL support
830 EXAMPLE: If you want all functions except of network
831 support you can write:
833 #include "config_cmd_all.h"
834 #undef CONFIG_CMD_NET
837 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
839 Note: Don't enable the "icache" and "dcache" commands
840 (configuration option CONFIG_CMD_CACHE) unless you know
841 what you (and your U-Boot users) are doing. Data
842 cache cannot be enabled on systems like the 8xx or
843 8260 (where accesses to the IMMR region must be
844 uncached), and it cannot be disabled on all other
845 systems where we (mis-) use the data cache to hold an
846 initial stack and some data.
849 XXX - this list needs to get updated!
853 If this variable is defined, U-Boot will use a device tree
854 to configure its devices, instead of relying on statically
855 compiled #defines in the board file. This option is
856 experimental and only available on a few boards. The device
857 tree is available in the global data as gd->fdt_blob.
859 U-Boot needs to get its device tree from somewhere. This can
860 be done using one of the two options below:
863 If this variable is defined, U-Boot will embed a device tree
864 binary in its image. This device tree file should be in the
865 board directory and called <soc>-<board>.dts. The binary file
866 is then picked up in board_init_f() and made available through
867 the global data structure as gd->blob.
870 If this variable is defined, U-Boot will build a device tree
871 binary. It will be called u-boot.dtb. Architecture-specific
872 code will locate it at run-time. Generally this works by:
874 cat u-boot.bin u-boot.dtb >image.bin
876 and in fact, U-Boot does this for you, creating a file called
877 u-boot-dtb.bin which is useful in the common case. You can
878 still use the individual files if you need something more
883 If this variable is defined, it enables watchdog
884 support for the SoC. There must be support in the SoC
885 specific code for a watchdog. For the 8xx and 8260
886 CPUs, the SIU Watchdog feature is enabled in the SYPCR
887 register. When supported for a specific SoC is
888 available, then no further board specific code should
892 When using a watchdog circuitry external to the used
893 SoC, then define this variable and provide board
894 specific code for the "hw_watchdog_reset" function.
897 CONFIG_VERSION_VARIABLE
898 If this variable is defined, an environment variable
899 named "ver" is created by U-Boot showing the U-Boot
900 version as printed by the "version" command.
901 This variable is readonly.
905 When CONFIG_CMD_DATE is selected, the type of the RTC
906 has to be selected, too. Define exactly one of the
909 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
910 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
911 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
912 CONFIG_RTC_MC146818 - use MC146818 RTC
913 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
914 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
915 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
916 CONFIG_RTC_DS164x - use Dallas DS164x RTC
917 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
918 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
919 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
920 CONFIG_SYS_RV3029_TCR - enable trickle charger on
923 Note that if the RTC uses I2C, then the I2C interface
924 must also be configured. See I2C Support, below.
927 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
928 CONFIG_PCA953X_INFO - enable pca953x info command
930 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
931 chip-ngpio pairs that tell the PCA953X driver the number of
932 pins supported by a particular chip.
934 Note that if the GPIO device uses I2C, then the I2C interface
935 must also be configured. See I2C Support, below.
939 When CONFIG_TIMESTAMP is selected, the timestamp
940 (date and time) of an image is printed by image
941 commands like bootm or iminfo. This option is
942 automatically enabled when you select CONFIG_CMD_DATE .
945 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
946 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
948 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
949 CONFIG_CMD_SCSI) you must configure support for at
950 least one partition type as well.
953 CONFIG_IDE_RESET_ROUTINE - this is defined in several
954 board configurations files but used nowhere!
956 CONFIG_IDE_RESET - is this is defined, IDE Reset will
957 be performed by calling the function
958 ide_set_reset(int reset)
959 which has to be defined in a board specific file
964 Set this to enable ATAPI support.
969 Set this to enable support for disks larger than 137GB
970 Also look at CONFIG_SYS_64BIT_LBA.
971 Whithout these , LBA48 support uses 32bit variables and will 'only'
972 support disks up to 2.1TB.
974 CONFIG_SYS_64BIT_LBA:
975 When enabled, makes the IDE subsystem use 64bit sector addresses.
979 At the moment only there is only support for the
980 SYM53C8XX SCSI controller; define
981 CONFIG_SCSI_SYM53C8XX to enable it.
983 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
984 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
985 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
986 maximum numbers of LUNs, SCSI ID's and target
988 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
990 - NETWORK Support (PCI):
992 Support for Intel 8254x/8257x gigabit chips.
995 Utility code for direct access to the SPI bus on Intel 8257x.
996 This does not do anything useful unless you set at least one
997 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
999 CONFIG_E1000_SPI_GENERIC
1000 Allow generic access to the SPI bus on the Intel 8257x, for
1001 example with the "sspi" command.
1004 Management command for E1000 devices. When used on devices
1005 with SPI support you can reprogram the EEPROM from U-Boot.
1007 CONFIG_E1000_FALLBACK_MAC
1008 default MAC for empty EEPROM after production.
1011 Support for Intel 82557/82559/82559ER chips.
1012 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1013 write routine for first time initialisation.
1016 Support for Digital 2114x chips.
1017 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1018 modem chip initialisation (KS8761/QS6611).
1021 Support for National dp83815 chips.
1024 Support for National dp8382[01] gigabit chips.
1026 - NETWORK Support (other):
1028 CONFIG_DRIVER_AT91EMAC
1029 Support for AT91RM9200 EMAC.
1032 Define this to use reduced MII inteface
1034 CONFIG_DRIVER_AT91EMAC_QUIET
1035 If this defined, the driver is quiet.
1036 The driver doen't show link status messages.
1038 CONFIG_CALXEDA_XGMAC
1039 Support for the Calxeda XGMAC device
1041 CONFIG_DRIVER_LAN91C96
1042 Support for SMSC's LAN91C96 chips.
1044 CONFIG_LAN91C96_BASE
1045 Define this to hold the physical address
1046 of the LAN91C96's I/O space
1048 CONFIG_LAN91C96_USE_32_BIT
1049 Define this to enable 32 bit addressing
1051 CONFIG_DRIVER_SMC91111
1052 Support for SMSC's LAN91C111 chip
1054 CONFIG_SMC91111_BASE
1055 Define this to hold the physical address
1056 of the device (I/O space)
1058 CONFIG_SMC_USE_32_BIT
1059 Define this if data bus is 32 bits
1061 CONFIG_SMC_USE_IOFUNCS
1062 Define this to use i/o functions instead of macros
1063 (some hardware wont work with macros)
1065 CONFIG_DRIVER_TI_EMAC
1066 Support for davinci emac
1068 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1069 Define this if you have more then 3 PHYs.
1072 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1074 CONFIG_FTGMAC100_EGIGA
1075 Define this to use GE link update with gigabit PHY.
1076 Define this if FTGMAC100 is connected to gigabit PHY.
1077 If your system has 10/100 PHY only, it might not occur
1078 wrong behavior. Because PHY usually return timeout or
1079 useless data when polling gigabit status and gigabit
1080 control registers. This behavior won't affect the
1081 correctnessof 10/100 link speed update.
1084 Support for SMSC's LAN911x and LAN921x chips
1087 Define this to hold the physical address
1088 of the device (I/O space)
1090 CONFIG_SMC911X_32_BIT
1091 Define this if data bus is 32 bits
1093 CONFIG_SMC911X_16_BIT
1094 Define this if data bus is 16 bits. If your processor
1095 automatically converts one 32 bit word to two 16 bit
1096 words you may also try CONFIG_SMC911X_32_BIT.
1099 Support for Renesas on-chip Ethernet controller
1101 CONFIG_SH_ETHER_USE_PORT
1102 Define the number of ports to be used
1104 CONFIG_SH_ETHER_PHY_ADDR
1105 Define the ETH PHY's address
1107 CONFIG_SH_ETHER_CACHE_WRITEBACK
1108 If this option is set, the driver enables cache flush.
1111 CONFIG_GENERIC_LPC_TPM
1112 Support for generic parallel port TPM devices. Only one device
1113 per system is supported at this time.
1115 CONFIG_TPM_TIS_BASE_ADDRESS
1116 Base address where the generic TPM device is mapped
1117 to. Contemporary x86 systems usually map it at
1121 At the moment only the UHCI host controller is
1122 supported (PIP405, MIP405, MPC5200); define
1123 CONFIG_USB_UHCI to enable it.
1124 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1125 and define CONFIG_USB_STORAGE to enable the USB
1128 Supported are USB Keyboards and USB Floppy drives
1130 MPC5200 USB requires additional defines:
1132 for 528 MHz Clock: 0x0001bbbb
1136 for differential drivers: 0x00001000
1137 for single ended drivers: 0x00005000
1138 for differential drivers on PSC3: 0x00000100
1139 for single ended drivers on PSC3: 0x00004100
1140 CONFIG_SYS_USB_EVENT_POLL
1141 May be defined to allow interrupt polling
1142 instead of using asynchronous interrupts
1145 Define the below if you wish to use the USB console.
1146 Once firmware is rebuilt from a serial console issue the
1147 command "setenv stdin usbtty; setenv stdout usbtty" and
1148 attach your USB cable. The Unix command "dmesg" should print
1149 it has found a new device. The environment variable usbtty
1150 can be set to gserial or cdc_acm to enable your device to
1151 appear to a USB host as a Linux gserial device or a
1152 Common Device Class Abstract Control Model serial device.
1153 If you select usbtty = gserial you should be able to enumerate
1155 # modprobe usbserial vendor=0xVendorID product=0xProductID
1156 else if using cdc_acm, simply setting the environment
1157 variable usbtty to be cdc_acm should suffice. The following
1158 might be defined in YourBoardName.h
1161 Define this to build a UDC device
1164 Define this to have a tty type of device available to
1165 talk to the UDC device
1167 CONFIG_SYS_CONSOLE_IS_IN_ENV
1168 Define this if you want stdin, stdout &/or stderr to
1172 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1173 Derive USB clock from external clock "blah"
1174 - CONFIG_SYS_USB_EXTC_CLK 0x02
1176 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1177 Derive USB clock from brgclk
1178 - CONFIG_SYS_USB_BRG_CLK 0x04
1180 If you have a USB-IF assigned VendorID then you may wish to
1181 define your own vendor specific values either in BoardName.h
1182 or directly in usbd_vendor_info.h. If you don't define
1183 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1184 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1185 should pretend to be a Linux device to it's target host.
1187 CONFIG_USBD_MANUFACTURER
1188 Define this string as the name of your company for
1189 - CONFIG_USBD_MANUFACTURER "my company"
1191 CONFIG_USBD_PRODUCT_NAME
1192 Define this string as the name of your product
1193 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1195 CONFIG_USBD_VENDORID
1196 Define this as your assigned Vendor ID from the USB
1197 Implementors Forum. This *must* be a genuine Vendor ID
1198 to avoid polluting the USB namespace.
1199 - CONFIG_USBD_VENDORID 0xFFFF
1201 CONFIG_USBD_PRODUCTID
1202 Define this as the unique Product ID
1204 - CONFIG_USBD_PRODUCTID 0xFFFF
1206 - ULPI Layer Support:
1207 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1208 the generic ULPI layer. The generic layer accesses the ULPI PHY
1209 via the platform viewport, so you need both the genric layer and
1210 the viewport enabled. Currently only Chipidea/ARC based
1211 viewport is supported.
1212 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1213 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1216 The MMC controller on the Intel PXA is supported. To
1217 enable this define CONFIG_MMC. The MMC can be
1218 accessed from the boot prompt by mapping the device
1219 to physical memory similar to flash. Command line is
1220 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1221 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1224 Support for Renesas on-chip MMCIF controller
1226 CONFIG_SH_MMCIF_ADDR
1227 Define the base address of MMCIF registers
1230 Define the clock frequency for MMCIF
1232 - Journaling Flash filesystem support:
1233 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1234 CONFIG_JFFS2_NAND_DEV
1235 Define these for a default partition on a NAND device
1237 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1238 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1239 Define these for a default partition on a NOR device
1241 CONFIG_SYS_JFFS_CUSTOM_PART
1242 Define this to create an own partition. You have to provide a
1243 function struct part_info* jffs2_part_info(int part_num)
1245 If you define only one JFFS2 partition you may also want to
1246 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1247 to disable the command chpart. This is the default when you
1248 have not defined a custom partition
1250 - FAT(File Allocation Table) filesystem write function support:
1252 Support for saving memory data as a file
1253 in FAT formatted partition
1258 Define this to enable standard (PC-Style) keyboard
1262 Standard PC keyboard driver with US (is default) and
1263 GERMAN key layout (switch via environment 'keymap=de') support.
1264 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1265 for cfb_console. Supports cursor blinking.
1270 Define this to enable video support (for output to
1273 CONFIG_VIDEO_CT69000
1275 Enable Chips & Technologies 69000 Video chip
1277 CONFIG_VIDEO_SMI_LYNXEM
1278 Enable Silicon Motion SMI 712/710/810 Video chip. The
1279 video output is selected via environment 'videoout'
1280 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1283 For the CT69000 and SMI_LYNXEM drivers, videomode is
1284 selected via environment 'videomode'. Two different ways
1286 - "videomode=num" 'num' is a standard LiLo mode numbers.
1287 Following standard modes are supported (* is default):
1289 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1290 -------------+---------------------------------------------
1291 8 bits | 0x301* 0x303 0x305 0x161 0x307
1292 15 bits | 0x310 0x313 0x316 0x162 0x319
1293 16 bits | 0x311 0x314 0x317 0x163 0x31A
1294 24 bits | 0x312 0x315 0x318 ? 0x31B
1295 -------------+---------------------------------------------
1296 (i.e. setenv videomode 317; saveenv; reset;)
1298 - "videomode=bootargs" all the video parameters are parsed
1299 from the bootargs. (See drivers/video/videomodes.c)
1302 CONFIG_VIDEO_SED13806
1303 Enable Epson SED13806 driver. This driver supports 8bpp
1304 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1305 or CONFIG_VIDEO_SED13806_16BPP
1308 Enable the Freescale DIU video driver. Reference boards for
1309 SOCs that have a DIU should define this macro to enable DIU
1310 support, and should also define these other macros:
1316 CONFIG_VIDEO_SW_CURSOR
1317 CONFIG_VGA_AS_SINGLE_DEVICE
1319 CONFIG_VIDEO_BMP_LOGO
1321 The DIU driver will look for the 'video-mode' environment
1322 variable, and if defined, enable the DIU as a console during
1323 boot. See the documentation file README.video for a
1324 description of this variable.
1329 Define this to enable a custom keyboard support.
1330 This simply calls drv_keyboard_init() which must be
1331 defined in your board-specific files.
1332 The only board using this so far is RBC823.
1334 - LCD Support: CONFIG_LCD
1336 Define this to enable LCD support (for output to LCD
1337 display); also select one of the supported displays
1338 by defining one of these:
1342 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1344 CONFIG_NEC_NL6448AC33:
1346 NEC NL6448AC33-18. Active, color, single scan.
1348 CONFIG_NEC_NL6448BC20
1350 NEC NL6448BC20-08. 6.5", 640x480.
1351 Active, color, single scan.
1353 CONFIG_NEC_NL6448BC33_54
1355 NEC NL6448BC33-54. 10.4", 640x480.
1356 Active, color, single scan.
1360 Sharp 320x240. Active, color, single scan.
1361 It isn't 16x9, and I am not sure what it is.
1363 CONFIG_SHARP_LQ64D341
1365 Sharp LQ64D341 display, 640x480.
1366 Active, color, single scan.
1370 HLD1045 display, 640x480.
1371 Active, color, single scan.
1375 Optrex CBL50840-2 NF-FW 99 22 M5
1377 Hitachi LMG6912RPFC-00T
1381 320x240. Black & white.
1383 Normally display is black on white background; define
1384 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1386 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1388 If this option is set, the environment is checked for
1389 a variable "splashimage". If found, the usual display
1390 of logo, copyright and system information on the LCD
1391 is suppressed and the BMP image at the address
1392 specified in "splashimage" is loaded instead. The
1393 console is redirected to the "nulldev", too. This
1394 allows for a "silent" boot where a splash screen is
1395 loaded very quickly after power-on.
1397 CONFIG_SPLASH_SCREEN_ALIGN
1399 If this option is set the splash image can be freely positioned
1400 on the screen. Environment variable "splashpos" specifies the
1401 position as "x,y". If a positive number is given it is used as
1402 number of pixel from left/top. If a negative number is given it
1403 is used as number of pixel from right/bottom. You can also
1404 specify 'm' for centering the image.
1407 setenv splashpos m,m
1408 => image at center of screen
1410 setenv splashpos 30,20
1411 => image at x = 30 and y = 20
1413 setenv splashpos -10,m
1414 => vertically centered image
1415 at x = dspWidth - bmpWidth - 9
1417 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1419 If this option is set, additionally to standard BMP
1420 images, gzipped BMP images can be displayed via the
1421 splashscreen support or the bmp command.
1423 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1425 If this option is set, 8-bit RLE compressed BMP images
1426 can be displayed via the splashscreen support or the
1429 - Compression support:
1432 If this option is set, support for bzip2 compressed
1433 images is included. If not, only uncompressed and gzip
1434 compressed images are supported.
1436 NOTE: the bzip2 algorithm requires a lot of RAM, so
1437 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1442 If this option is set, support for lzma compressed
1445 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1446 requires an amount of dynamic memory that is given by the
1449 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1451 Where lc and lp stand for, respectively, Literal context bits
1452 and Literal pos bits.
1454 This value is upper-bounded by 14MB in the worst case. Anyway,
1455 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1456 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1457 a very small buffer.
1459 Use the lzmainfo tool to determinate the lc and lp values and
1460 then calculate the amount of needed dynamic memory (ensuring
1461 the appropriate CONFIG_SYS_MALLOC_LEN value).
1466 The address of PHY on MII bus.
1468 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1470 The clock frequency of the MII bus
1474 If this option is set, support for speed/duplex
1475 detection of gigabit PHY is included.
1477 CONFIG_PHY_RESET_DELAY
1479 Some PHY like Intel LXT971A need extra delay after
1480 reset before any MII register access is possible.
1481 For such PHY, set this option to the usec delay
1482 required. (minimum 300usec for LXT971A)
1484 CONFIG_PHY_CMD_DELAY (ppc4xx)
1486 Some PHY like Intel LXT971A need extra delay after
1487 command issued before MII status register can be read
1497 Define a default value for Ethernet address to use
1498 for the respective Ethernet interface, in case this
1499 is not determined automatically.
1504 Define a default value for the IP address to use for
1505 the default Ethernet interface, in case this is not
1506 determined through e.g. bootp.
1507 (Environment variable "ipaddr")
1509 - Server IP address:
1512 Defines a default value for the IP address of a TFTP
1513 server to contact when using the "tftboot" command.
1514 (Environment variable "serverip")
1516 CONFIG_KEEP_SERVERADDR
1518 Keeps the server's MAC address, in the env 'serveraddr'
1519 for passing to bootargs (like Linux's netconsole option)
1521 - Gateway IP address:
1524 Defines a default value for the IP address of the
1525 default router where packets to other networks are
1527 (Environment variable "gatewayip")
1532 Defines a default value for the subnet mask (or
1533 routing prefix) which is used to determine if an IP
1534 address belongs to the local subnet or needs to be
1535 forwarded through a router.
1536 (Environment variable "netmask")
1538 - Multicast TFTP Mode:
1541 Defines whether you want to support multicast TFTP as per
1542 rfc-2090; for example to work with atftp. Lets lots of targets
1543 tftp down the same boot image concurrently. Note: the Ethernet
1544 driver in use must provide a function: mcast() to join/leave a
1547 - BOOTP Recovery Mode:
1548 CONFIG_BOOTP_RANDOM_DELAY
1550 If you have many targets in a network that try to
1551 boot using BOOTP, you may want to avoid that all
1552 systems send out BOOTP requests at precisely the same
1553 moment (which would happen for instance at recovery
1554 from a power failure, when all systems will try to
1555 boot, thus flooding the BOOTP server. Defining
1556 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1557 inserted before sending out BOOTP requests. The
1558 following delays are inserted then:
1560 1st BOOTP request: delay 0 ... 1 sec
1561 2nd BOOTP request: delay 0 ... 2 sec
1562 3rd BOOTP request: delay 0 ... 4 sec
1564 BOOTP requests: delay 0 ... 8 sec
1566 - DHCP Advanced Options:
1567 You can fine tune the DHCP functionality by defining
1568 CONFIG_BOOTP_* symbols:
1570 CONFIG_BOOTP_SUBNETMASK
1571 CONFIG_BOOTP_GATEWAY
1572 CONFIG_BOOTP_HOSTNAME
1573 CONFIG_BOOTP_NISDOMAIN
1574 CONFIG_BOOTP_BOOTPATH
1575 CONFIG_BOOTP_BOOTFILESIZE
1578 CONFIG_BOOTP_SEND_HOSTNAME
1579 CONFIG_BOOTP_NTPSERVER
1580 CONFIG_BOOTP_TIMEOFFSET
1581 CONFIG_BOOTP_VENDOREX
1583 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1584 environment variable, not the BOOTP server.
1586 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1587 serverip from a DHCP server, it is possible that more
1588 than one DNS serverip is offered to the client.
1589 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1590 serverip will be stored in the additional environment
1591 variable "dnsip2". The first DNS serverip is always
1592 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1595 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1596 to do a dynamic update of a DNS server. To do this, they
1597 need the hostname of the DHCP requester.
1598 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1599 of the "hostname" environment variable is passed as
1600 option 12 to the DHCP server.
1602 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1604 A 32bit value in microseconds for a delay between
1605 receiving a "DHCP Offer" and sending the "DHCP Request".
1606 This fixes a problem with certain DHCP servers that don't
1607 respond 100% of the time to a "DHCP request". E.g. On an
1608 AT91RM9200 processor running at 180MHz, this delay needed
1609 to be *at least* 15,000 usec before a Windows Server 2003
1610 DHCP server would reply 100% of the time. I recommend at
1611 least 50,000 usec to be safe. The alternative is to hope
1612 that one of the retries will be successful but note that
1613 the DHCP timeout and retry process takes a longer than
1617 CONFIG_CDP_DEVICE_ID
1619 The device id used in CDP trigger frames.
1621 CONFIG_CDP_DEVICE_ID_PREFIX
1623 A two character string which is prefixed to the MAC address
1628 A printf format string which contains the ascii name of
1629 the port. Normally is set to "eth%d" which sets
1630 eth0 for the first Ethernet, eth1 for the second etc.
1632 CONFIG_CDP_CAPABILITIES
1634 A 32bit integer which indicates the device capabilities;
1635 0x00000010 for a normal host which does not forwards.
1639 An ascii string containing the version of the software.
1643 An ascii string containing the name of the platform.
1647 A 32bit integer sent on the trigger.
1649 CONFIG_CDP_POWER_CONSUMPTION
1651 A 16bit integer containing the power consumption of the
1652 device in .1 of milliwatts.
1654 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1656 A byte containing the id of the VLAN.
1658 - Status LED: CONFIG_STATUS_LED
1660 Several configurations allow to display the current
1661 status using a LED. For instance, the LED will blink
1662 fast while running U-Boot code, stop blinking as
1663 soon as a reply to a BOOTP request was received, and
1664 start blinking slow once the Linux kernel is running
1665 (supported by a status LED driver in the Linux
1666 kernel). Defining CONFIG_STATUS_LED enables this
1669 - CAN Support: CONFIG_CAN_DRIVER
1671 Defining CONFIG_CAN_DRIVER enables CAN driver support
1672 on those systems that support this (optional)
1673 feature, like the TQM8xxL modules.
1675 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1677 These enable I2C serial bus commands. Defining either of
1678 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1679 include the appropriate I2C driver for the selected CPU.
1681 This will allow you to use i2c commands at the u-boot
1682 command line (as long as you set CONFIG_CMD_I2C in
1683 CONFIG_COMMANDS) and communicate with i2c based realtime
1684 clock chips. See common/cmd_i2c.c for a description of the
1685 command line interface.
1687 CONFIG_HARD_I2C selects a hardware I2C controller.
1689 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1690 bit-banging) driver instead of CPM or similar hardware
1693 There are several other quantities that must also be
1694 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1696 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1697 to be the frequency (in Hz) at which you wish your i2c bus
1698 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1699 the CPU's i2c node address).
1701 Now, the u-boot i2c code for the mpc8xx
1702 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1703 and so its address should therefore be cleared to 0 (See,
1704 eg, MPC823e User's Manual p.16-473). So, set
1705 CONFIG_SYS_I2C_SLAVE to 0.
1707 CONFIG_SYS_I2C_INIT_MPC5XXX
1709 When a board is reset during an i2c bus transfer
1710 chips might think that the current transfer is still
1711 in progress. Reset the slave devices by sending start
1712 commands until the slave device responds.
1714 That's all that's required for CONFIG_HARD_I2C.
1716 If you use the software i2c interface (CONFIG_SOFT_I2C)
1717 then the following macros need to be defined (examples are
1718 from include/configs/lwmon.h):
1722 (Optional). Any commands necessary to enable the I2C
1723 controller or configure ports.
1725 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1729 (Only for MPC8260 CPU). The I/O port to use (the code
1730 assumes both bits are on the same port). Valid values
1731 are 0..3 for ports A..D.
1735 The code necessary to make the I2C data line active
1736 (driven). If the data line is open collector, this
1739 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1743 The code necessary to make the I2C data line tri-stated
1744 (inactive). If the data line is open collector, this
1747 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1751 Code that returns TRUE if the I2C data line is high,
1754 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1758 If <bit> is TRUE, sets the I2C data line high. If it
1759 is FALSE, it clears it (low).
1761 eg: #define I2C_SDA(bit) \
1762 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1763 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1767 If <bit> is TRUE, sets the I2C clock line high. If it
1768 is FALSE, it clears it (low).
1770 eg: #define I2C_SCL(bit) \
1771 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1772 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1776 This delay is invoked four times per clock cycle so this
1777 controls the rate of data transfer. The data rate thus
1778 is 1 / (I2C_DELAY * 4). Often defined to be something
1781 #define I2C_DELAY udelay(2)
1783 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1785 If your arch supports the generic GPIO framework (asm/gpio.h),
1786 then you may alternatively define the two GPIOs that are to be
1787 used as SCL / SDA. Any of the previous I2C_xxx macros will
1788 have GPIO-based defaults assigned to them as appropriate.
1790 You should define these to the GPIO value as given directly to
1791 the generic GPIO functions.
1793 CONFIG_SYS_I2C_INIT_BOARD
1795 When a board is reset during an i2c bus transfer
1796 chips might think that the current transfer is still
1797 in progress. On some boards it is possible to access
1798 the i2c SCLK line directly, either by using the
1799 processor pin as a GPIO or by having a second pin
1800 connected to the bus. If this option is defined a
1801 custom i2c_init_board() routine in boards/xxx/board.c
1802 is run early in the boot sequence.
1804 CONFIG_SYS_I2C_BOARD_LATE_INIT
1806 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1807 defined a custom i2c_board_late_init() routine in
1808 boards/xxx/board.c is run AFTER the operations in i2c_init()
1809 is completed. This callpoint can be used to unreset i2c bus
1810 using CPU i2c controller register accesses for CPUs whose i2c
1811 controller provide such a method. It is called at the end of
1812 i2c_init() to allow i2c_init operations to setup the i2c bus
1813 controller on the CPU (e.g. setting bus speed & slave address).
1815 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1817 This option enables configuration of bi_iic_fast[] flags
1818 in u-boot bd_info structure based on u-boot environment
1819 variable "i2cfast". (see also i2cfast)
1821 CONFIG_I2C_MULTI_BUS
1823 This option allows the use of multiple I2C buses, each of which
1824 must have a controller. At any point in time, only one bus is
1825 active. To switch to a different bus, use the 'i2c dev' command.
1826 Note that bus numbering is zero-based.
1828 CONFIG_SYS_I2C_NOPROBES
1830 This option specifies a list of I2C devices that will be skipped
1831 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1832 is set, specify a list of bus-device pairs. Otherwise, specify
1833 a 1D array of device addresses
1836 #undef CONFIG_I2C_MULTI_BUS
1837 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1839 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1841 #define CONFIG_I2C_MULTI_BUS
1842 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1844 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1846 CONFIG_SYS_SPD_BUS_NUM
1848 If defined, then this indicates the I2C bus number for DDR SPD.
1849 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1851 CONFIG_SYS_RTC_BUS_NUM
1853 If defined, then this indicates the I2C bus number for the RTC.
1854 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1856 CONFIG_SYS_DTT_BUS_NUM
1858 If defined, then this indicates the I2C bus number for the DTT.
1859 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1861 CONFIG_SYS_I2C_DTT_ADDR:
1863 If defined, specifies the I2C address of the DTT device.
1864 If not defined, then U-Boot uses predefined value for
1865 specified DTT device.
1869 Define this option if you want to use Freescale's I2C driver in
1870 drivers/i2c/fsl_i2c.c.
1874 Define this option if you have I2C devices reached over 1 .. n
1875 I2C Muxes like the pca9544a. This option addes a new I2C
1876 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1877 new I2C Bus to the existing I2C Busses. If you select the
1878 new Bus with "i2c dev", u-bbot sends first the commandos for
1879 the muxes to activate this new "bus".
1881 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1885 Adding a new I2C Bus reached over 2 pca9544a muxes
1886 The First mux with address 70 and channel 6
1887 The Second mux with address 71 and channel 4
1889 => i2c bus pca9544a:70:6:pca9544a:71:4
1891 Use the "i2c bus" command without parameter, to get a list
1892 of I2C Busses with muxes:
1895 Busses reached over muxes:
1897 reached over Mux(es):
1900 reached over Mux(es):
1905 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1906 u-boot first sends the command to the mux@70 to enable
1907 channel 6, and then the command to the mux@71 to enable
1910 After that, you can use the "normal" i2c commands as
1911 usual to communicate with your I2C devices behind
1914 This option is actually implemented for the bitbanging
1915 algorithm in common/soft_i2c.c and for the Hardware I2C
1916 Bus on the MPC8260. But it should be not so difficult
1917 to add this option to other architectures.
1919 CONFIG_SOFT_I2C_READ_REPEATED_START
1921 defining this will force the i2c_read() function in
1922 the soft_i2c driver to perform an I2C repeated start
1923 between writing the address pointer and reading the
1924 data. If this define is omitted the default behaviour
1925 of doing a stop-start sequence will be used. Most I2C
1926 devices can use either method, but some require one or
1929 - SPI Support: CONFIG_SPI
1931 Enables SPI driver (so far only tested with
1932 SPI EEPROM, also an instance works with Crystal A/D and
1933 D/As on the SACSng board)
1937 Enables the driver for SPI controller on SuperH. Currently
1938 only SH7757 is supported.
1942 Enables extended (16-bit) SPI EEPROM addressing.
1943 (symmetrical to CONFIG_I2C_X)
1947 Enables a software (bit-bang) SPI driver rather than
1948 using hardware support. This is a general purpose
1949 driver that only requires three general I/O port pins
1950 (two outputs, one input) to function. If this is
1951 defined, the board configuration must define several
1952 SPI configuration items (port pins to use, etc). For
1953 an example, see include/configs/sacsng.h.
1957 Enables a hardware SPI driver for general-purpose reads
1958 and writes. As with CONFIG_SOFT_SPI, the board configuration
1959 must define a list of chip-select function pointers.
1960 Currently supported on some MPC8xxx processors. For an
1961 example, see include/configs/mpc8349emds.h.
1965 Enables the driver for the SPI controllers on i.MX and MXC
1966 SoCs. Currently i.MX31/35/51 are supported.
1968 - FPGA Support: CONFIG_FPGA
1970 Enables FPGA subsystem.
1972 CONFIG_FPGA_<vendor>
1974 Enables support for specific chip vendors.
1977 CONFIG_FPGA_<family>
1979 Enables support for FPGA family.
1980 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1984 Specify the number of FPGA devices to support.
1986 CONFIG_SYS_FPGA_PROG_FEEDBACK
1988 Enable printing of hash marks during FPGA configuration.
1990 CONFIG_SYS_FPGA_CHECK_BUSY
1992 Enable checks on FPGA configuration interface busy
1993 status by the configuration function. This option
1994 will require a board or device specific function to
1999 If defined, a function that provides delays in the FPGA
2000 configuration driver.
2002 CONFIG_SYS_FPGA_CHECK_CTRLC
2003 Allow Control-C to interrupt FPGA configuration
2005 CONFIG_SYS_FPGA_CHECK_ERROR
2007 Check for configuration errors during FPGA bitfile
2008 loading. For example, abort during Virtex II
2009 configuration if the INIT_B line goes low (which
2010 indicated a CRC error).
2012 CONFIG_SYS_FPGA_WAIT_INIT
2014 Maximum time to wait for the INIT_B line to deassert
2015 after PROB_B has been deasserted during a Virtex II
2016 FPGA configuration sequence. The default time is 500
2019 CONFIG_SYS_FPGA_WAIT_BUSY
2021 Maximum time to wait for BUSY to deassert during
2022 Virtex II FPGA configuration. The default is 5 ms.
2024 CONFIG_SYS_FPGA_WAIT_CONFIG
2026 Time to wait after FPGA configuration. The default is
2029 - Configuration Management:
2032 If defined, this string will be added to the U-Boot
2033 version information (U_BOOT_VERSION)
2035 - Vendor Parameter Protection:
2037 U-Boot considers the values of the environment
2038 variables "serial#" (Board Serial Number) and
2039 "ethaddr" (Ethernet Address) to be parameters that
2040 are set once by the board vendor / manufacturer, and
2041 protects these variables from casual modification by
2042 the user. Once set, these variables are read-only,
2043 and write or delete attempts are rejected. You can
2044 change this behaviour:
2046 If CONFIG_ENV_OVERWRITE is #defined in your config
2047 file, the write protection for vendor parameters is
2048 completely disabled. Anybody can change or delete
2051 Alternatively, if you #define _both_ CONFIG_ETHADDR
2052 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2053 Ethernet address is installed in the environment,
2054 which can be changed exactly ONCE by the user. [The
2055 serial# is unaffected by this, i. e. it remains
2061 Define this variable to enable the reservation of
2062 "protected RAM", i. e. RAM which is not overwritten
2063 by U-Boot. Define CONFIG_PRAM to hold the number of
2064 kB you want to reserve for pRAM. You can overwrite
2065 this default value by defining an environment
2066 variable "pram" to the number of kB you want to
2067 reserve. Note that the board info structure will
2068 still show the full amount of RAM. If pRAM is
2069 reserved, a new environment variable "mem" will
2070 automatically be defined to hold the amount of
2071 remaining RAM in a form that can be passed as boot
2072 argument to Linux, for instance like that:
2074 setenv bootargs ... mem=\${mem}
2077 This way you can tell Linux not to use this memory,
2078 either, which results in a memory region that will
2079 not be affected by reboots.
2081 *WARNING* If your board configuration uses automatic
2082 detection of the RAM size, you must make sure that
2083 this memory test is non-destructive. So far, the
2084 following board configurations are known to be
2087 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2088 HERMES, IP860, RPXlite, LWMON, LANTEC,
2094 Define this variable to stop the system in case of a
2095 fatal error, so that you have to reset it manually.
2096 This is probably NOT a good idea for an embedded
2097 system where you want the system to reboot
2098 automatically as fast as possible, but it may be
2099 useful during development since you can try to debug
2100 the conditions that lead to the situation.
2102 CONFIG_NET_RETRY_COUNT
2104 This variable defines the number of retries for
2105 network operations like ARP, RARP, TFTP, or BOOTP
2106 before giving up the operation. If not defined, a
2107 default value of 5 is used.
2111 Timeout waiting for an ARP reply in milliseconds.
2113 - Command Interpreter:
2114 CONFIG_AUTO_COMPLETE
2116 Enable auto completion of commands using TAB.
2118 Note that this feature has NOT been implemented yet
2119 for the "hush" shell.
2122 CONFIG_SYS_HUSH_PARSER
2124 Define this variable to enable the "hush" shell (from
2125 Busybox) as command line interpreter, thus enabling
2126 powerful command line syntax like
2127 if...then...else...fi conditionals or `&&' and '||'
2128 constructs ("shell scripts").
2130 If undefined, you get the old, much simpler behaviour
2131 with a somewhat smaller memory footprint.
2134 CONFIG_SYS_PROMPT_HUSH_PS2
2136 This defines the secondary prompt string, which is
2137 printed when the command interpreter needs more input
2138 to complete a command. Usually "> ".
2142 In the current implementation, the local variables
2143 space and global environment variables space are
2144 separated. Local variables are those you define by
2145 simply typing `name=value'. To access a local
2146 variable later on, you have write `$name' or
2147 `${name}'; to execute the contents of a variable
2148 directly type `$name' at the command prompt.
2150 Global environment variables are those you use
2151 setenv/printenv to work with. To run a command stored
2152 in such a variable, you need to use the run command,
2153 and you must not use the '$' sign to access them.
2155 To store commands and special characters in a
2156 variable, please use double quotation marks
2157 surrounding the whole text of the variable, instead
2158 of the backslashes before semicolons and special
2161 - Commandline Editing and History:
2162 CONFIG_CMDLINE_EDITING
2164 Enable editing and History functions for interactive
2165 commandline input operations
2167 - Default Environment:
2168 CONFIG_EXTRA_ENV_SETTINGS
2170 Define this to contain any number of null terminated
2171 strings (variable = value pairs) that will be part of
2172 the default environment compiled into the boot image.
2174 For example, place something like this in your
2175 board's config file:
2177 #define CONFIG_EXTRA_ENV_SETTINGS \
2181 Warning: This method is based on knowledge about the
2182 internal format how the environment is stored by the
2183 U-Boot code. This is NOT an official, exported
2184 interface! Although it is unlikely that this format
2185 will change soon, there is no guarantee either.
2186 You better know what you are doing here.
2188 Note: overly (ab)use of the default environment is
2189 discouraged. Make sure to check other ways to preset
2190 the environment like the "source" command or the
2193 - DataFlash Support:
2194 CONFIG_HAS_DATAFLASH
2196 Defining this option enables DataFlash features and
2197 allows to read/write in Dataflash via the standard
2200 - SystemACE Support:
2203 Adding this option adds support for Xilinx SystemACE
2204 chips attached via some sort of local bus. The address
2205 of the chip must also be defined in the
2206 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2208 #define CONFIG_SYSTEMACE
2209 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2211 When SystemACE support is added, the "ace" device type
2212 becomes available to the fat commands, i.e. fatls.
2214 - TFTP Fixed UDP Port:
2217 If this is defined, the environment variable tftpsrcp
2218 is used to supply the TFTP UDP source port value.
2219 If tftpsrcp isn't defined, the normal pseudo-random port
2220 number generator is used.
2222 Also, the environment variable tftpdstp is used to supply
2223 the TFTP UDP destination port value. If tftpdstp isn't
2224 defined, the normal port 69 is used.
2226 The purpose for tftpsrcp is to allow a TFTP server to
2227 blindly start the TFTP transfer using the pre-configured
2228 target IP address and UDP port. This has the effect of
2229 "punching through" the (Windows XP) firewall, allowing
2230 the remainder of the TFTP transfer to proceed normally.
2231 A better solution is to properly configure the firewall,
2232 but sometimes that is not allowed.
2234 - Show boot progress:
2235 CONFIG_SHOW_BOOT_PROGRESS
2237 Defining this option allows to add some board-
2238 specific code (calling a user-provided function
2239 "show_boot_progress(int)") that enables you to show
2240 the system's boot progress on some display (for
2241 example, some LED's) on your board. At the moment,
2242 the following checkpoints are implemented:
2244 Legacy uImage format:
2247 1 common/cmd_bootm.c before attempting to boot an image
2248 -1 common/cmd_bootm.c Image header has bad magic number
2249 2 common/cmd_bootm.c Image header has correct magic number
2250 -2 common/cmd_bootm.c Image header has bad checksum
2251 3 common/cmd_bootm.c Image header has correct checksum
2252 -3 common/cmd_bootm.c Image data has bad checksum
2253 4 common/cmd_bootm.c Image data has correct checksum
2254 -4 common/cmd_bootm.c Image is for unsupported architecture
2255 5 common/cmd_bootm.c Architecture check OK
2256 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2257 6 common/cmd_bootm.c Image Type check OK
2258 -6 common/cmd_bootm.c gunzip uncompression error
2259 -7 common/cmd_bootm.c Unimplemented compression type
2260 7 common/cmd_bootm.c Uncompression OK
2261 8 common/cmd_bootm.c No uncompress/copy overwrite error
2262 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2264 9 common/image.c Start initial ramdisk verification
2265 -10 common/image.c Ramdisk header has bad magic number
2266 -11 common/image.c Ramdisk header has bad checksum
2267 10 common/image.c Ramdisk header is OK
2268 -12 common/image.c Ramdisk data has bad checksum
2269 11 common/image.c Ramdisk data has correct checksum
2270 12 common/image.c Ramdisk verification complete, start loading
2271 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2272 13 common/image.c Start multifile image verification
2273 14 common/image.c No initial ramdisk, no multifile, continue.
2275 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2277 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2278 -31 post/post.c POST test failed, detected by post_output_backlog()
2279 -32 post/post.c POST test failed, detected by post_run_single()
2281 34 common/cmd_doc.c before loading a Image from a DOC device
2282 -35 common/cmd_doc.c Bad usage of "doc" command
2283 35 common/cmd_doc.c correct usage of "doc" command
2284 -36 common/cmd_doc.c No boot device
2285 36 common/cmd_doc.c correct boot device
2286 -37 common/cmd_doc.c Unknown Chip ID on boot device
2287 37 common/cmd_doc.c correct chip ID found, device available
2288 -38 common/cmd_doc.c Read Error on boot device
2289 38 common/cmd_doc.c reading Image header from DOC device OK
2290 -39 common/cmd_doc.c Image header has bad magic number
2291 39 common/cmd_doc.c Image header has correct magic number
2292 -40 common/cmd_doc.c Error reading Image from DOC device
2293 40 common/cmd_doc.c Image header has correct magic number
2294 41 common/cmd_ide.c before loading a Image from a IDE device
2295 -42 common/cmd_ide.c Bad usage of "ide" command
2296 42 common/cmd_ide.c correct usage of "ide" command
2297 -43 common/cmd_ide.c No boot device
2298 43 common/cmd_ide.c boot device found
2299 -44 common/cmd_ide.c Device not available
2300 44 common/cmd_ide.c Device available
2301 -45 common/cmd_ide.c wrong partition selected
2302 45 common/cmd_ide.c partition selected
2303 -46 common/cmd_ide.c Unknown partition table
2304 46 common/cmd_ide.c valid partition table found
2305 -47 common/cmd_ide.c Invalid partition type
2306 47 common/cmd_ide.c correct partition type
2307 -48 common/cmd_ide.c Error reading Image Header on boot device
2308 48 common/cmd_ide.c reading Image Header from IDE device OK
2309 -49 common/cmd_ide.c Image header has bad magic number
2310 49 common/cmd_ide.c Image header has correct magic number
2311 -50 common/cmd_ide.c Image header has bad checksum
2312 50 common/cmd_ide.c Image header has correct checksum
2313 -51 common/cmd_ide.c Error reading Image from IDE device
2314 51 common/cmd_ide.c reading Image from IDE device OK
2315 52 common/cmd_nand.c before loading a Image from a NAND device
2316 -53 common/cmd_nand.c Bad usage of "nand" command
2317 53 common/cmd_nand.c correct usage of "nand" command
2318 -54 common/cmd_nand.c No boot device
2319 54 common/cmd_nand.c boot device found
2320 -55 common/cmd_nand.c Unknown Chip ID on boot device
2321 55 common/cmd_nand.c correct chip ID found, device available
2322 -56 common/cmd_nand.c Error reading Image Header on boot device
2323 56 common/cmd_nand.c reading Image Header from NAND device OK
2324 -57 common/cmd_nand.c Image header has bad magic number
2325 57 common/cmd_nand.c Image header has correct magic number
2326 -58 common/cmd_nand.c Error reading Image from NAND device
2327 58 common/cmd_nand.c reading Image from NAND device OK
2329 -60 common/env_common.c Environment has a bad CRC, using default
2331 64 net/eth.c starting with Ethernet configuration.
2332 -64 net/eth.c no Ethernet found.
2333 65 net/eth.c Ethernet found.
2335 -80 common/cmd_net.c usage wrong
2336 80 common/cmd_net.c before calling NetLoop()
2337 -81 common/cmd_net.c some error in NetLoop() occurred
2338 81 common/cmd_net.c NetLoop() back without error
2339 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2340 82 common/cmd_net.c trying automatic boot
2341 83 common/cmd_net.c running "source" command
2342 -83 common/cmd_net.c some error in automatic boot or "source" command
2343 84 common/cmd_net.c end without errors
2348 100 common/cmd_bootm.c Kernel FIT Image has correct format
2349 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2350 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2351 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2352 102 common/cmd_bootm.c Kernel unit name specified
2353 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2354 103 common/cmd_bootm.c Found configuration node
2355 104 common/cmd_bootm.c Got kernel subimage node offset
2356 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2357 105 common/cmd_bootm.c Kernel subimage hash verification OK
2358 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2359 106 common/cmd_bootm.c Architecture check OK
2360 -106 common/cmd_bootm.c Kernel subimage has wrong type
2361 107 common/cmd_bootm.c Kernel subimage type OK
2362 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2363 108 common/cmd_bootm.c Got kernel subimage data/size
2364 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2365 -109 common/cmd_bootm.c Can't get kernel subimage type
2366 -110 common/cmd_bootm.c Can't get kernel subimage comp
2367 -111 common/cmd_bootm.c Can't get kernel subimage os
2368 -112 common/cmd_bootm.c Can't get kernel subimage load address
2369 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2371 120 common/image.c Start initial ramdisk verification
2372 -120 common/image.c Ramdisk FIT image has incorrect format
2373 121 common/image.c Ramdisk FIT image has correct format
2374 122 common/image.c No ramdisk subimage unit name, using configuration
2375 -122 common/image.c Can't get configuration for ramdisk subimage
2376 123 common/image.c Ramdisk unit name specified
2377 -124 common/image.c Can't get ramdisk subimage node offset
2378 125 common/image.c Got ramdisk subimage node offset
2379 -125 common/image.c Ramdisk subimage hash verification failed
2380 126 common/image.c Ramdisk subimage hash verification OK
2381 -126 common/image.c Ramdisk subimage for unsupported architecture
2382 127 common/image.c Architecture check OK
2383 -127 common/image.c Can't get ramdisk subimage data/size
2384 128 common/image.c Got ramdisk subimage data/size
2385 129 common/image.c Can't get ramdisk load address
2386 -129 common/image.c Got ramdisk load address
2388 -130 common/cmd_doc.c Incorrect FIT image format
2389 131 common/cmd_doc.c FIT image format OK
2391 -140 common/cmd_ide.c Incorrect FIT image format
2392 141 common/cmd_ide.c FIT image format OK
2394 -150 common/cmd_nand.c Incorrect FIT image format
2395 151 common/cmd_nand.c FIT image format OK
2397 - Standalone program support:
2398 CONFIG_STANDALONE_LOAD_ADDR
2400 This option defines a board specific value for the
2401 address where standalone program gets loaded, thus
2402 overwriting the architecture dependent default
2405 - Frame Buffer Address:
2408 Define CONFIG_FB_ADDR if you want to use specific
2409 address for frame buffer.
2410 Then system will reserve the frame buffer address to
2411 defined address instead of lcd_setmem (this function
2412 grabs the memory for frame buffer by panel's size).
2414 Please see board_init_f function.
2416 - Automatic software updates via TFTP server
2418 CONFIG_UPDATE_TFTP_CNT_MAX
2419 CONFIG_UPDATE_TFTP_MSEC_MAX
2421 These options enable and control the auto-update feature;
2422 for a more detailed description refer to doc/README.update.
2424 - MTD Support (mtdparts command, UBI support)
2427 Adds the MTD device infrastructure from the Linux kernel.
2428 Needed for mtdparts command support.
2430 CONFIG_MTD_PARTITIONS
2432 Adds the MTD partitioning infrastructure from the Linux
2433 kernel. Needed for UBI support.
2437 Enable building of SPL globally.
2439 CONFIG_SPL_TEXT_BASE
2440 TEXT_BASE for linking the SPL binary.
2443 LDSCRIPT for linking the SPL binary.
2445 CONFIG_SPL_LIBCOMMON_SUPPORT
2446 Support for common/libcommon.o in SPL binary
2448 CONFIG_SPL_LIBDISK_SUPPORT
2449 Support for disk/libdisk.o in SPL binary
2451 CONFIG_SPL_I2C_SUPPORT
2452 Support for drivers/i2c/libi2c.o in SPL binary
2454 CONFIG_SPL_GPIO_SUPPORT
2455 Support for drivers/gpio/libgpio.o in SPL binary
2457 CONFIG_SPL_MMC_SUPPORT
2458 Support for drivers/mmc/libmmc.o in SPL binary
2460 CONFIG_SPL_SERIAL_SUPPORT
2461 Support for drivers/serial/libserial.o in SPL binary
2463 CONFIG_SPL_SPI_FLASH_SUPPORT
2464 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2466 CONFIG_SPL_SPI_SUPPORT
2467 Support for drivers/spi/libspi.o in SPL binary
2469 CONFIG_SPL_FAT_SUPPORT
2470 Support for fs/fat/libfat.o in SPL binary
2472 CONFIG_SPL_LIBGENERIC_SUPPORT
2473 Support for lib/libgeneric.o in SPL binary
2478 [so far only for SMDK2400 boards]
2480 - Modem support enable:
2481 CONFIG_MODEM_SUPPORT
2483 - RTS/CTS Flow control enable:
2486 - Modem debug support:
2487 CONFIG_MODEM_SUPPORT_DEBUG
2489 Enables debugging stuff (char screen[1024], dbg())
2490 for modem support. Useful only with BDI2000.
2492 - Interrupt support (PPC):
2494 There are common interrupt_init() and timer_interrupt()
2495 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2496 for CPU specific initialization. interrupt_init_cpu()
2497 should set decrementer_count to appropriate value. If
2498 CPU resets decrementer automatically after interrupt
2499 (ppc4xx) it should set decrementer_count to zero.
2500 timer_interrupt() calls timer_interrupt_cpu() for CPU
2501 specific handling. If board has watchdog / status_led
2502 / other_activity_monitor it works automatically from
2503 general timer_interrupt().
2507 In the target system modem support is enabled when a
2508 specific key (key combination) is pressed during
2509 power-on. Otherwise U-Boot will boot normally
2510 (autoboot). The key_pressed() function is called from
2511 board_init(). Currently key_pressed() is a dummy
2512 function, returning 1 and thus enabling modem
2515 If there are no modem init strings in the
2516 environment, U-Boot proceed to autoboot; the
2517 previous output (banner, info printfs) will be
2520 See also: doc/README.Modem
2522 Board initialization settings:
2523 ------------------------------
2525 During Initialization u-boot calls a number of board specific functions
2526 to allow the preparation of board specific prerequisites, e.g. pin setup
2527 before drivers are initialized. To enable these callbacks the
2528 following configuration macros have to be defined. Currently this is
2529 architecture specific, so please check arch/your_architecture/lib/board.c
2530 typically in board_init_f() and board_init_r().
2532 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2533 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2534 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2535 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2537 Configuration Settings:
2538 -----------------------
2540 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2541 undefine this when you're short of memory.
2543 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2544 width of the commands listed in the 'help' command output.
2546 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2547 prompt for user input.
2549 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2551 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2553 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2555 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2556 the application (usually a Linux kernel) when it is
2559 - CONFIG_SYS_BAUDRATE_TABLE:
2560 List of legal baudrate settings for this board.
2562 - CONFIG_SYS_CONSOLE_INFO_QUIET
2563 Suppress display of console information at boot.
2565 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2566 If the board specific function
2567 extern int overwrite_console (void);
2568 returns 1, the stdin, stderr and stdout are switched to the
2569 serial port, else the settings in the environment are used.
2571 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2572 Enable the call to overwrite_console().
2574 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2575 Enable overwrite of previous console environment settings.
2577 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2578 Begin and End addresses of the area used by the
2581 - CONFIG_SYS_ALT_MEMTEST:
2582 Enable an alternate, more extensive memory test.
2584 - CONFIG_SYS_MEMTEST_SCRATCH:
2585 Scratch address used by the alternate memory test
2586 You only need to set this if address zero isn't writeable
2588 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2589 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2590 this specified memory area will get subtracted from the top
2591 (end) of RAM and won't get "touched" at all by U-Boot. By
2592 fixing up gd->ram_size the Linux kernel should gets passed
2593 the now "corrected" memory size and won't touch it either.
2594 This should work for arch/ppc and arch/powerpc. Only Linux
2595 board ports in arch/powerpc with bootwrapper support that
2596 recalculate the memory size from the SDRAM controller setup
2597 will have to get fixed in Linux additionally.
2599 This option can be used as a workaround for the 440EPx/GRx
2600 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2603 WARNING: Please make sure that this value is a multiple of
2604 the Linux page size (normally 4k). If this is not the case,
2605 then the end address of the Linux memory will be located at a
2606 non page size aligned address and this could cause major
2609 - CONFIG_SYS_TFTP_LOADADDR:
2610 Default load address for network file downloads
2612 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2613 Enable temporary baudrate change while serial download
2615 - CONFIG_SYS_SDRAM_BASE:
2616 Physical start address of SDRAM. _Must_ be 0 here.
2618 - CONFIG_SYS_MBIO_BASE:
2619 Physical start address of Motherboard I/O (if using a
2622 - CONFIG_SYS_FLASH_BASE:
2623 Physical start address of Flash memory.
2625 - CONFIG_SYS_MONITOR_BASE:
2626 Physical start address of boot monitor code (set by
2627 make config files to be same as the text base address
2628 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2629 CONFIG_SYS_FLASH_BASE when booting from flash.
2631 - CONFIG_SYS_MONITOR_LEN:
2632 Size of memory reserved for monitor code, used to
2633 determine _at_compile_time_ (!) if the environment is
2634 embedded within the U-Boot image, or in a separate
2637 - CONFIG_SYS_MALLOC_LEN:
2638 Size of DRAM reserved for malloc() use.
2640 - CONFIG_SYS_BOOTM_LEN:
2641 Normally compressed uImages are limited to an
2642 uncompressed size of 8 MBytes. If this is not enough,
2643 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2644 to adjust this setting to your needs.
2646 - CONFIG_SYS_BOOTMAPSZ:
2647 Maximum size of memory mapped by the startup code of
2648 the Linux kernel; all data that must be processed by
2649 the Linux kernel (bd_info, boot arguments, FDT blob if
2650 used) must be put below this limit, unless "bootm_low"
2651 enviroment variable is defined and non-zero. In such case
2652 all data for the Linux kernel must be between "bootm_low"
2653 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2654 variable "bootm_mapsize" will override the value of
2655 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2656 then the value in "bootm_size" will be used instead.
2658 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2659 Enable initrd_high functionality. If defined then the
2660 initrd_high feature is enabled and the bootm ramdisk subcommand
2663 - CONFIG_SYS_BOOT_GET_CMDLINE:
2664 Enables allocating and saving kernel cmdline in space between
2665 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2667 - CONFIG_SYS_BOOT_GET_KBD:
2668 Enables allocating and saving a kernel copy of the bd_info in
2669 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2671 - CONFIG_SYS_MAX_FLASH_BANKS:
2672 Max number of Flash memory banks
2674 - CONFIG_SYS_MAX_FLASH_SECT:
2675 Max number of sectors on a Flash chip
2677 - CONFIG_SYS_FLASH_ERASE_TOUT:
2678 Timeout for Flash erase operations (in ms)
2680 - CONFIG_SYS_FLASH_WRITE_TOUT:
2681 Timeout for Flash write operations (in ms)
2683 - CONFIG_SYS_FLASH_LOCK_TOUT
2684 Timeout for Flash set sector lock bit operation (in ms)
2686 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2687 Timeout for Flash clear lock bits operation (in ms)
2689 - CONFIG_SYS_FLASH_PROTECTION
2690 If defined, hardware flash sectors protection is used
2691 instead of U-Boot software protection.
2693 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2695 Enable TFTP transfers directly to flash memory;
2696 without this option such a download has to be
2697 performed in two steps: (1) download to RAM, and (2)
2698 copy from RAM to flash.
2700 The two-step approach is usually more reliable, since
2701 you can check if the download worked before you erase
2702 the flash, but in some situations (when system RAM is
2703 too limited to allow for a temporary copy of the
2704 downloaded image) this option may be very useful.
2706 - CONFIG_SYS_FLASH_CFI:
2707 Define if the flash driver uses extra elements in the
2708 common flash structure for storing flash geometry.
2710 - CONFIG_FLASH_CFI_DRIVER
2711 This option also enables the building of the cfi_flash driver
2712 in the drivers directory
2714 - CONFIG_FLASH_CFI_MTD
2715 This option enables the building of the cfi_mtd driver
2716 in the drivers directory. The driver exports CFI flash
2719 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2720 Use buffered writes to flash.
2722 - CONFIG_FLASH_SPANSION_S29WS_N
2723 s29ws-n MirrorBit flash has non-standard addresses for buffered
2726 - CONFIG_SYS_FLASH_QUIET_TEST
2727 If this option is defined, the common CFI flash doesn't
2728 print it's warning upon not recognized FLASH banks. This
2729 is useful, if some of the configured banks are only
2730 optionally available.
2732 - CONFIG_FLASH_SHOW_PROGRESS
2733 If defined (must be an integer), print out countdown
2734 digits and dots. Recommended value: 45 (9..1) for 80
2735 column displays, 15 (3..1) for 40 column displays.
2737 - CONFIG_SYS_RX_ETH_BUFFER:
2738 Defines the number of Ethernet receive buffers. On some
2739 Ethernet controllers it is recommended to set this value
2740 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2741 buffers can be full shortly after enabling the interface
2742 on high Ethernet traffic.
2743 Defaults to 4 if not defined.
2745 - CONFIG_ENV_MAX_ENTRIES
2747 Maximum number of entries in the hash table that is used
2748 internally to store the environment settings. The default
2749 setting is supposed to be generous and should work in most
2750 cases. This setting can be used to tune behaviour; see
2751 lib/hashtable.c for details.
2753 The following definitions that deal with the placement and management
2754 of environment data (variable area); in general, we support the
2755 following configurations:
2757 - CONFIG_BUILD_ENVCRC:
2759 Builds up envcrc with the target environment so that external utils
2760 may easily extract it and embed it in final U-Boot images.
2762 - CONFIG_ENV_IS_IN_FLASH:
2764 Define this if the environment is in flash memory.
2766 a) The environment occupies one whole flash sector, which is
2767 "embedded" in the text segment with the U-Boot code. This
2768 happens usually with "bottom boot sector" or "top boot
2769 sector" type flash chips, which have several smaller
2770 sectors at the start or the end. For instance, such a
2771 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2772 such a case you would place the environment in one of the
2773 4 kB sectors - with U-Boot code before and after it. With
2774 "top boot sector" type flash chips, you would put the
2775 environment in one of the last sectors, leaving a gap
2776 between U-Boot and the environment.
2778 - CONFIG_ENV_OFFSET:
2780 Offset of environment data (variable area) to the
2781 beginning of flash memory; for instance, with bottom boot
2782 type flash chips the second sector can be used: the offset
2783 for this sector is given here.
2785 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2789 This is just another way to specify the start address of
2790 the flash sector containing the environment (instead of
2793 - CONFIG_ENV_SECT_SIZE:
2795 Size of the sector containing the environment.
2798 b) Sometimes flash chips have few, equal sized, BIG sectors.
2799 In such a case you don't want to spend a whole sector for
2804 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2805 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2806 of this flash sector for the environment. This saves
2807 memory for the RAM copy of the environment.
2809 It may also save flash memory if you decide to use this
2810 when your environment is "embedded" within U-Boot code,
2811 since then the remainder of the flash sector could be used
2812 for U-Boot code. It should be pointed out that this is
2813 STRONGLY DISCOURAGED from a robustness point of view:
2814 updating the environment in flash makes it always
2815 necessary to erase the WHOLE sector. If something goes
2816 wrong before the contents has been restored from a copy in
2817 RAM, your target system will be dead.
2819 - CONFIG_ENV_ADDR_REDUND
2820 CONFIG_ENV_SIZE_REDUND
2822 These settings describe a second storage area used to hold
2823 a redundant copy of the environment data, so that there is
2824 a valid backup copy in case there is a power failure during
2825 a "saveenv" operation.
2827 BE CAREFUL! Any changes to the flash layout, and some changes to the
2828 source code will make it necessary to adapt <board>/u-boot.lds*
2832 - CONFIG_ENV_IS_IN_NVRAM:
2834 Define this if you have some non-volatile memory device
2835 (NVRAM, battery buffered SRAM) which you want to use for the
2841 These two #defines are used to determine the memory area you
2842 want to use for environment. It is assumed that this memory
2843 can just be read and written to, without any special
2846 BE CAREFUL! The first access to the environment happens quite early
2847 in U-Boot initalization (when we try to get the setting of for the
2848 console baudrate). You *MUST* have mapped your NVRAM area then, or
2851 Please note that even with NVRAM we still use a copy of the
2852 environment in RAM: we could work on NVRAM directly, but we want to
2853 keep settings there always unmodified except somebody uses "saveenv"
2854 to save the current settings.
2857 - CONFIG_ENV_IS_IN_EEPROM:
2859 Use this if you have an EEPROM or similar serial access
2860 device and a driver for it.
2862 - CONFIG_ENV_OFFSET:
2865 These two #defines specify the offset and size of the
2866 environment area within the total memory of your EEPROM.
2868 - CONFIG_SYS_I2C_EEPROM_ADDR:
2869 If defined, specified the chip address of the EEPROM device.
2870 The default address is zero.
2872 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2873 If defined, the number of bits used to address bytes in a
2874 single page in the EEPROM device. A 64 byte page, for example
2875 would require six bits.
2877 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2878 If defined, the number of milliseconds to delay between
2879 page writes. The default is zero milliseconds.
2881 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2882 The length in bytes of the EEPROM memory array address. Note
2883 that this is NOT the chip address length!
2885 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2886 EEPROM chips that implement "address overflow" are ones
2887 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2888 address and the extra bits end up in the "chip address" bit
2889 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2892 Note that we consider the length of the address field to
2893 still be one byte because the extra address bits are hidden
2894 in the chip address.
2896 - CONFIG_SYS_EEPROM_SIZE:
2897 The size in bytes of the EEPROM device.
2899 - CONFIG_ENV_EEPROM_IS_ON_I2C
2900 define this, if you have I2C and SPI activated, and your
2901 EEPROM, which holds the environment, is on the I2C bus.
2903 - CONFIG_I2C_ENV_EEPROM_BUS
2904 if you have an Environment on an EEPROM reached over
2905 I2C muxes, you can define here, how to reach this
2906 EEPROM. For example:
2908 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2910 EEPROM which holds the environment, is reached over
2911 a pca9547 i2c mux with address 0x70, channel 3.
2913 - CONFIG_ENV_IS_IN_DATAFLASH:
2915 Define this if you have a DataFlash memory device which you
2916 want to use for the environment.
2918 - CONFIG_ENV_OFFSET:
2922 These three #defines specify the offset and size of the
2923 environment area within the total memory of your DataFlash placed
2924 at the specified address.
2926 - CONFIG_ENV_IS_IN_NAND:
2928 Define this if you have a NAND device which you want to use
2929 for the environment.
2931 - CONFIG_ENV_OFFSET:
2934 These two #defines specify the offset and size of the environment
2935 area within the first NAND device. CONFIG_ENV_OFFSET must be
2936 aligned to an erase block boundary.
2938 - CONFIG_ENV_OFFSET_REDUND (optional):
2940 This setting describes a second storage area of CONFIG_ENV_SIZE
2941 size used to hold a redundant copy of the environment data, so
2942 that there is a valid backup copy in case there is a power failure
2943 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2944 aligned to an erase block boundary.
2946 - CONFIG_ENV_RANGE (optional):
2948 Specifies the length of the region in which the environment
2949 can be written. This should be a multiple of the NAND device's
2950 block size. Specifying a range with more erase blocks than
2951 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2952 the range to be avoided.
2954 - CONFIG_ENV_OFFSET_OOB (optional):
2956 Enables support for dynamically retrieving the offset of the
2957 environment from block zero's out-of-band data. The
2958 "nand env.oob" command can be used to record this offset.
2959 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2960 using CONFIG_ENV_OFFSET_OOB.
2962 - CONFIG_NAND_ENV_DST
2964 Defines address in RAM to which the nand_spl code should copy the
2965 environment. If redundant environment is used, it will be copied to
2966 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2968 - CONFIG_SYS_SPI_INIT_OFFSET
2970 Defines offset to the initial SPI buffer area in DPRAM. The
2971 area is used at an early stage (ROM part) if the environment
2972 is configured to reside in the SPI EEPROM: We need a 520 byte
2973 scratch DPRAM area. It is used between the two initialization
2974 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2975 to be a good choice since it makes it far enough from the
2976 start of the data area as well as from the stack pointer.
2978 Please note that the environment is read-only until the monitor
2979 has been relocated to RAM and a RAM copy of the environment has been
2980 created; also, when using EEPROM you will have to use getenv_f()
2981 until then to read environment variables.
2983 The environment is protected by a CRC32 checksum. Before the monitor
2984 is relocated into RAM, as a result of a bad CRC you will be working
2985 with the compiled-in default environment - *silently*!!! [This is
2986 necessary, because the first environment variable we need is the
2987 "baudrate" setting for the console - if we have a bad CRC, we don't
2988 have any device yet where we could complain.]
2990 Note: once the monitor has been relocated, then it will complain if
2991 the default environment is used; a new CRC is computed as soon as you
2992 use the "saveenv" command to store a valid environment.
2994 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2995 Echo the inverted Ethernet link state to the fault LED.
2997 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2998 also needs to be defined.
3000 - CONFIG_SYS_FAULT_MII_ADDR:
3001 MII address of the PHY to check for the Ethernet link state.
3003 - CONFIG_NS16550_MIN_FUNCTIONS:
3004 Define this if you desire to only have use of the NS16550_init
3005 and NS16550_putc functions for the serial driver located at
3006 drivers/serial/ns16550.c. This option is useful for saving
3007 space for already greatly restricted images, including but not
3008 limited to NAND_SPL configurations.
3010 Low Level (hardware related) configuration options:
3011 ---------------------------------------------------
3013 - CONFIG_SYS_CACHELINE_SIZE:
3014 Cache Line Size of the CPU.
3016 - CONFIG_SYS_DEFAULT_IMMR:
3017 Default address of the IMMR after system reset.
3019 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3020 and RPXsuper) to be able to adjust the position of
3021 the IMMR register after a reset.
3023 - CONFIG_SYS_CCSRBAR_DEFAULT:
3024 Default (power-on reset) physical address of CCSR on Freescale
3027 - CONFIG_SYS_CCSRBAR:
3028 Virtual address of CCSR. On a 32-bit build, this is typically
3029 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3031 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3032 for cross-platform code that uses that macro instead.
3034 - CONFIG_SYS_CCSRBAR_PHYS:
3035 Physical address of CCSR. CCSR can be relocated to a new
3036 physical address, if desired. In this case, this macro should
3037 be set to that address. Otherwise, it should be set to the
3038 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3039 is typically relocated on 36-bit builds. It is recommended
3040 that this macro be defined via the _HIGH and _LOW macros:
3042 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3043 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3045 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3046 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3047 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3048 used in assembly code, so it must not contain typecasts or
3049 integer size suffixes (e.g. "ULL").
3051 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3052 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3053 used in assembly code, so it must not contain typecasts or
3054 integer size suffixes (e.g. "ULL").
3056 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3057 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3058 forced to a value that ensures that CCSR is not relocated.
3060 - Floppy Disk Support:
3061 CONFIG_SYS_FDC_DRIVE_NUMBER
3063 the default drive number (default value 0)
3065 CONFIG_SYS_ISA_IO_STRIDE
3067 defines the spacing between FDC chipset registers
3070 CONFIG_SYS_ISA_IO_OFFSET
3072 defines the offset of register from address. It
3073 depends on which part of the data bus is connected to
3074 the FDC chipset. (default value 0)
3076 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3077 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3080 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3081 fdc_hw_init() is called at the beginning of the FDC
3082 setup. fdc_hw_init() must be provided by the board
3083 source code. It is used to make hardware dependant
3087 Most IDE controllers were designed to be connected with PCI
3088 interface. Only few of them were designed for AHB interface.
3089 When software is doing ATA command and data transfer to
3090 IDE devices through IDE-AHB controller, some additional
3091 registers accessing to these kind of IDE-AHB controller
3094 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3095 DO NOT CHANGE unless you know exactly what you're
3096 doing! (11-4) [MPC8xx/82xx systems only]
3098 - CONFIG_SYS_INIT_RAM_ADDR:
3100 Start address of memory area that can be used for
3101 initial data and stack; please note that this must be
3102 writable memory that is working WITHOUT special
3103 initialization, i. e. you CANNOT use normal RAM which
3104 will become available only after programming the
3105 memory controller and running certain initialization
3108 U-Boot uses the following memory types:
3109 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3110 - MPC824X: data cache
3111 - PPC4xx: data cache
3113 - CONFIG_SYS_GBL_DATA_OFFSET:
3115 Offset of the initial data structure in the memory
3116 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3117 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3118 data is located at the end of the available space
3119 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3120 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3121 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3122 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3125 On the MPC824X (or other systems that use the data
3126 cache for initial memory) the address chosen for
3127 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3128 point to an otherwise UNUSED address space between
3129 the top of RAM and the start of the PCI space.
3131 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3133 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3135 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3137 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3139 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3141 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3143 - CONFIG_SYS_OR_TIMING_SDRAM:
3146 - CONFIG_SYS_MAMR_PTA:
3147 periodic timer for refresh
3149 - CONFIG_SYS_DER: Debug Event Register (37-47)
3151 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3152 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3153 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3154 CONFIG_SYS_BR1_PRELIM:
3155 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3157 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3158 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3159 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3160 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3162 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3163 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3164 Machine Mode Register and Memory Periodic Timer
3165 Prescaler definitions (SDRAM timing)
3167 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3168 enable I2C microcode relocation patch (MPC8xx);
3169 define relocation offset in DPRAM [DSP2]
3171 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3172 enable SMC microcode relocation patch (MPC8xx);
3173 define relocation offset in DPRAM [SMC1]
3175 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3176 enable SPI microcode relocation patch (MPC8xx);
3177 define relocation offset in DPRAM [SCC4]
3179 - CONFIG_SYS_USE_OSCCLK:
3180 Use OSCM clock mode on MBX8xx board. Be careful,
3181 wrong setting might damage your board. Read
3182 doc/README.MBX before setting this variable!
3184 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3185 Offset of the bootmode word in DPRAM used by post
3186 (Power On Self Tests). This definition overrides
3187 #define'd default value in commproc.h resp.
3190 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3191 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3192 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3193 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3194 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3195 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3196 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3197 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3198 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3200 - CONFIG_PCI_DISABLE_PCIE:
3201 Disable PCI-Express on systems where it is supported but not
3205 Chip has SRIO or not
3208 Board has SRIO 1 port available
3211 Board has SRIO 2 port available
3213 - CONFIG_SYS_SRIOn_MEM_VIRT:
3214 Virtual Address of SRIO port 'n' memory region
3216 - CONFIG_SYS_SRIOn_MEM_PHYS:
3217 Physical Address of SRIO port 'n' memory region
3219 - CONFIG_SYS_SRIOn_MEM_SIZE:
3220 Size of SRIO port 'n' memory region
3222 - CONFIG_SYS_NDFC_16
3223 Defined to tell the NDFC that the NAND chip is using a
3226 - CONFIG_SYS_NDFC_EBC0_CFG
3227 Sets the EBC0_CFG register for the NDFC. If not defined
3228 a default value will be used.
3231 Get DDR timing information from an I2C EEPROM. Common
3232 with pluggable memory modules such as SODIMMs
3235 I2C address of the SPD EEPROM
3237 - CONFIG_SYS_SPD_BUS_NUM
3238 If SPD EEPROM is on an I2C bus other than the first
3239 one, specify here. Note that the value must resolve
3240 to something your driver can deal with.
3242 - CONFIG_SYS_DDR_RAW_TIMING
3243 Get DDR timing information from other than SPD. Common with
3244 soldered DDR chips onboard without SPD. DDR raw timing
3245 parameters are extracted from datasheet and hard-coded into
3246 header files or board specific files.
3248 - CONFIG_FSL_DDR_INTERACTIVE
3249 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3251 - CONFIG_SYS_83XX_DDR_USES_CS0
3252 Only for 83xx systems. If specified, then DDR should
3253 be configured using CS0 and CS1 instead of CS2 and CS3.
3255 - CONFIG_ETHER_ON_FEC[12]
3256 Define to enable FEC[12] on a 8xx series processor.
3258 - CONFIG_FEC[12]_PHY
3259 Define to the hardcoded PHY address which corresponds
3260 to the given FEC; i. e.
3261 #define CONFIG_FEC1_PHY 4
3262 means that the PHY with address 4 is connected to FEC1
3264 When set to -1, means to probe for first available.
3266 - CONFIG_FEC[12]_PHY_NORXERR
3267 The PHY does not have a RXERR line (RMII only).
3268 (so program the FEC to ignore it).
3271 Enable RMII mode for all FECs.
3272 Note that this is a global option, we can't
3273 have one FEC in standard MII mode and another in RMII mode.
3275 - CONFIG_CRC32_VERIFY
3276 Add a verify option to the crc32 command.
3279 => crc32 -v <address> <count> <crc32>
3281 Where address/count indicate a memory area
3282 and crc32 is the correct crc32 which the
3286 Add the "loopw" memory command. This only takes effect if
3287 the memory commands are activated globally (CONFIG_CMD_MEM).
3290 Add the "mdc" and "mwc" memory commands. These are cyclic
3295 This command will print 4 bytes (10,11,12,13) each 500 ms.
3297 => mwc.l 100 12345678 10
3298 This command will write 12345678 to address 100 all 10 ms.
3300 This only takes effect if the memory commands are activated
3301 globally (CONFIG_CMD_MEM).
3303 - CONFIG_SKIP_LOWLEVEL_INIT
3304 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3305 low level initializations (like setting up the memory
3306 controller) are omitted and/or U-Boot does not
3307 relocate itself into RAM.
3309 Normally this variable MUST NOT be defined. The only
3310 exception is when U-Boot is loaded (to RAM) by some
3311 other boot loader or by a debugger which performs
3312 these initializations itself.
3315 Modifies the behaviour of start.S when compiling a loader
3316 that is executed before the actual U-Boot. E.g. when
3317 compiling a NAND SPL.
3319 - CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3320 define this, if you want to read first the oob data
3321 and then the data. This is used for example on
3324 - CONFIG_USE_ARCH_MEMCPY
3325 CONFIG_USE_ARCH_MEMSET
3326 If these options are used a optimized version of memcpy/memset will
3327 be used if available. These functions may be faster under some
3328 conditions but may increase the binary size.
3330 Freescale QE/FMAN Firmware Support:
3331 -----------------------------------
3333 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3334 loading of "firmware", which is encoded in the QE firmware binary format.
3335 This firmware often needs to be loaded during U-Boot booting, so macros
3336 are used to identify the storage device (NOR flash, SPI, etc) and the address
3339 - CONFIG_SYS_QE_FMAN_FW_ADDR
3340 The address in the storage device where the firmware is located. The
3341 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3344 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3345 The maximum possible size of the firmware. The firmware binary format
3346 has a field that specifies the actual size of the firmware, but it
3347 might not be possible to read any part of the firmware unless some
3348 local storage is allocated to hold the entire firmware first.
3350 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3351 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3352 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3353 virtual address in NOR flash.
3355 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3356 Specifies that QE/FMAN firmware is located in NAND flash.
3357 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3359 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3360 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3361 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3363 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3364 Specifies that QE/FMAN firmware is located on the primary SPI
3365 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3368 Building the Software:
3369 ======================
3371 Building U-Boot has been tested in several native build environments
3372 and in many different cross environments. Of course we cannot support
3373 all possibly existing versions of cross development tools in all
3374 (potentially obsolete) versions. In case of tool chain problems we
3375 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3376 which is extensively used to build and test U-Boot.
3378 If you are not using a native environment, it is assumed that you
3379 have GNU cross compiling tools available in your path. In this case,
3380 you must set the environment variable CROSS_COMPILE in your shell.
3381 Note that no changes to the Makefile or any other source files are
3382 necessary. For example using the ELDK on a 4xx CPU, please enter:
3384 $ CROSS_COMPILE=ppc_4xx-
3385 $ export CROSS_COMPILE
3387 Note: If you wish to generate Windows versions of the utilities in
3388 the tools directory you can use the MinGW toolchain
3389 (http://www.mingw.org). Set your HOST tools to the MinGW
3390 toolchain and execute 'make tools'. For example:
3392 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3394 Binaries such as tools/mkimage.exe will be created which can
3395 be executed on computers running Windows.
3397 U-Boot is intended to be simple to build. After installing the
3398 sources you must configure U-Boot for one specific board type. This
3403 where "NAME_config" is the name of one of the existing configu-
3404 rations; see the main Makefile for supported names.
3406 Note: for some board special configuration names may exist; check if
3407 additional information is available from the board vendor; for
3408 instance, the TQM823L systems are available without (standard)
3409 or with LCD support. You can select such additional "features"
3410 when choosing the configuration, i. e.
3413 - will configure for a plain TQM823L, i. e. no LCD support
3415 make TQM823L_LCD_config
3416 - will configure for a TQM823L with U-Boot console on LCD
3421 Finally, type "make all", and you should get some working U-Boot
3422 images ready for download to / installation on your system:
3424 - "u-boot.bin" is a raw binary image
3425 - "u-boot" is an image in ELF binary format
3426 - "u-boot.srec" is in Motorola S-Record format
3428 By default the build is performed locally and the objects are saved
3429 in the source directory. One of the two methods can be used to change
3430 this behavior and build U-Boot to some external directory:
3432 1. Add O= to the make command line invocations:
3434 make O=/tmp/build distclean
3435 make O=/tmp/build NAME_config
3436 make O=/tmp/build all
3438 2. Set environment variable BUILD_DIR to point to the desired location:
3440 export BUILD_DIR=/tmp/build
3445 Note that the command line "O=" setting overrides the BUILD_DIR environment
3449 Please be aware that the Makefiles assume you are using GNU make, so
3450 for instance on NetBSD you might need to use "gmake" instead of
3454 If the system board that you have is not listed, then you will need
3455 to port U-Boot to your hardware platform. To do this, follow these
3458 1. Add a new configuration option for your board to the toplevel
3459 "Makefile" and to the "MAKEALL" script, using the existing
3460 entries as examples. Note that here and at many other places
3461 boards and other names are listed in alphabetical sort order. Please
3463 2. Create a new directory to hold your board specific code. Add any
3464 files you need. In your board directory, you will need at least
3465 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3466 3. Create a new configuration file "include/configs/<board>.h" for
3468 3. If you're porting U-Boot to a new CPU, then also create a new
3469 directory to hold your CPU specific code. Add any files you need.
3470 4. Run "make <board>_config" with your new name.
3471 5. Type "make", and you should get a working "u-boot.srec" file
3472 to be installed on your target system.
3473 6. Debug and solve any problems that might arise.
3474 [Of course, this last step is much harder than it sounds.]
3477 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3478 ==============================================================
3480 If you have modified U-Boot sources (for instance added a new board
3481 or support for new devices, a new CPU, etc.) you are expected to
3482 provide feedback to the other developers. The feedback normally takes
3483 the form of a "patch", i. e. a context diff against a certain (latest
3484 official or latest in the git repository) version of U-Boot sources.
3486 But before you submit such a patch, please verify that your modifi-
3487 cation did not break existing code. At least make sure that *ALL* of
3488 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3489 just run the "MAKEALL" script, which will configure and build U-Boot
3490 for ALL supported system. Be warned, this will take a while. You can
3491 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3492 environment variable to the script, i. e. to use the ELDK cross tools
3495 CROSS_COMPILE=ppc_8xx- MAKEALL
3497 or to build on a native PowerPC system you can type
3499 CROSS_COMPILE=' ' MAKEALL
3501 When using the MAKEALL script, the default behaviour is to build
3502 U-Boot in the source directory. This location can be changed by
3503 setting the BUILD_DIR environment variable. Also, for each target
3504 built, the MAKEALL script saves two log files (<target>.ERR and
3505 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3506 location can be changed by setting the MAKEALL_LOGDIR environment
3507 variable. For example:
3509 export BUILD_DIR=/tmp/build
3510 export MAKEALL_LOGDIR=/tmp/log
3511 CROSS_COMPILE=ppc_8xx- MAKEALL
3513 With the above settings build objects are saved in the /tmp/build,
3514 log files are saved in the /tmp/log and the source tree remains clean
3515 during the whole build process.
3518 See also "U-Boot Porting Guide" below.
3521 Monitor Commands - Overview:
3522 ============================
3524 go - start application at address 'addr'
3525 run - run commands in an environment variable
3526 bootm - boot application image from memory
3527 bootp - boot image via network using BootP/TFTP protocol
3528 tftpboot- boot image via network using TFTP protocol
3529 and env variables "ipaddr" and "serverip"
3530 (and eventually "gatewayip")
3531 tftpput - upload a file via network using TFTP protocol
3532 rarpboot- boot image via network using RARP/TFTP protocol
3533 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3534 loads - load S-Record file over serial line
3535 loadb - load binary file over serial line (kermit mode)
3537 mm - memory modify (auto-incrementing)
3538 nm - memory modify (constant address)
3539 mw - memory write (fill)
3541 cmp - memory compare
3542 crc32 - checksum calculation
3543 i2c - I2C sub-system
3544 sspi - SPI utility commands
3545 base - print or set address offset
3546 printenv- print environment variables
3547 setenv - set environment variables
3548 saveenv - save environment variables to persistent storage
3549 protect - enable or disable FLASH write protection
3550 erase - erase FLASH memory
3551 flinfo - print FLASH memory information
3552 bdinfo - print Board Info structure
3553 iminfo - print header information for application image
3554 coninfo - print console devices and informations
3555 ide - IDE sub-system
3556 loop - infinite loop on address range
3557 loopw - infinite write loop on address range
3558 mtest - simple RAM test
3559 icache - enable or disable instruction cache
3560 dcache - enable or disable data cache
3561 reset - Perform RESET of the CPU
3562 echo - echo args to console
3563 version - print monitor version
3564 help - print online help
3565 ? - alias for 'help'
3568 Monitor Commands - Detailed Description:
3569 ========================================
3573 For now: just type "help <command>".
3576 Environment Variables:
3577 ======================
3579 U-Boot supports user configuration using Environment Variables which
3580 can be made persistent by saving to Flash memory.
3582 Environment Variables are set using "setenv", printed using
3583 "printenv", and saved to Flash using "saveenv". Using "setenv"
3584 without a value can be used to delete a variable from the
3585 environment. As long as you don't save the environment you are
3586 working with an in-memory copy. In case the Flash area containing the
3587 environment is erased by accident, a default environment is provided.
3589 Some configuration options can be set using Environment Variables.
3591 List of environment variables (most likely not complete):
3593 baudrate - see CONFIG_BAUDRATE
3595 bootdelay - see CONFIG_BOOTDELAY
3597 bootcmd - see CONFIG_BOOTCOMMAND
3599 bootargs - Boot arguments when booting an RTOS image
3601 bootfile - Name of the image to load with TFTP
3603 bootm_low - Memory range available for image processing in the bootm
3604 command can be restricted. This variable is given as
3605 a hexadecimal number and defines lowest address allowed
3606 for use by the bootm command. See also "bootm_size"
3607 environment variable. Address defined by "bootm_low" is
3608 also the base of the initial memory mapping for the Linux
3609 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3612 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3613 This variable is given as a hexadecimal number and it
3614 defines the size of the memory region starting at base
3615 address bootm_low that is accessible by the Linux kernel
3616 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3617 as the default value if it is defined, and bootm_size is
3620 bootm_size - Memory range available for image processing in the bootm
3621 command can be restricted. This variable is given as
3622 a hexadecimal number and defines the size of the region
3623 allowed for use by the bootm command. See also "bootm_low"
3624 environment variable.
3626 updatefile - Location of the software update file on a TFTP server, used
3627 by the automatic software update feature. Please refer to
3628 documentation in doc/README.update for more details.
3630 autoload - if set to "no" (any string beginning with 'n'),
3631 "bootp" will just load perform a lookup of the
3632 configuration from the BOOTP server, but not try to
3633 load any image using TFTP
3635 autostart - if set to "yes", an image loaded using the "bootp",
3636 "rarpboot", "tftpboot" or "diskboot" commands will
3637 be automatically started (by internally calling
3640 If set to "no", a standalone image passed to the
3641 "bootm" command will be copied to the load address
3642 (and eventually uncompressed), but NOT be started.
3643 This can be used to load and uncompress arbitrary
3646 fdt_high - if set this restricts the maximum address that the
3647 flattened device tree will be copied into upon boot.
3648 If this is set to the special value 0xFFFFFFFF then
3649 the fdt will not be copied at all on boot. For this
3650 to work it must reside in writable memory, have
3651 sufficient padding on the end of it for u-boot to
3652 add the information it needs into it, and the memory
3653 must be accessible by the kernel.
3655 fdtcontroladdr- if set this is the address of the control flattened
3656 device tree used by U-Boot when CONFIG_OF_CONTROL is
3659 i2cfast - (PPC405GP|PPC405EP only)
3660 if set to 'y' configures Linux I2C driver for fast
3661 mode (400kHZ). This environment variable is used in
3662 initialization code. So, for changes to be effective
3663 it must be saved and board must be reset.
3665 initrd_high - restrict positioning of initrd images:
3666 If this variable is not set, initrd images will be
3667 copied to the highest possible address in RAM; this
3668 is usually what you want since it allows for
3669 maximum initrd size. If for some reason you want to
3670 make sure that the initrd image is loaded below the
3671 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3672 variable to a value of "no" or "off" or "0".
3673 Alternatively, you can set it to a maximum upper
3674 address to use (U-Boot will still check that it
3675 does not overwrite the U-Boot stack and data).
3677 For instance, when you have a system with 16 MB
3678 RAM, and want to reserve 4 MB from use by Linux,
3679 you can do this by adding "mem=12M" to the value of
3680 the "bootargs" variable. However, now you must make
3681 sure that the initrd image is placed in the first
3682 12 MB as well - this can be done with
3684 setenv initrd_high 00c00000
3686 If you set initrd_high to 0xFFFFFFFF, this is an
3687 indication to U-Boot that all addresses are legal
3688 for the Linux kernel, including addresses in flash
3689 memory. In this case U-Boot will NOT COPY the
3690 ramdisk at all. This may be useful to reduce the
3691 boot time on your system, but requires that this
3692 feature is supported by your Linux kernel.
3694 ipaddr - IP address; needed for tftpboot command
3696 loadaddr - Default load address for commands like "bootp",
3697 "rarpboot", "tftpboot", "loadb" or "diskboot"
3699 loads_echo - see CONFIG_LOADS_ECHO
3701 serverip - TFTP server IP address; needed for tftpboot command
3703 bootretry - see CONFIG_BOOT_RETRY_TIME
3705 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3707 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3709 ethprime - controls which interface is used first.
3711 ethact - controls which interface is currently active.
3712 For example you can do the following
3714 => setenv ethact FEC
3715 => ping 192.168.0.1 # traffic sent on FEC
3716 => setenv ethact SCC
3717 => ping 10.0.0.1 # traffic sent on SCC
3719 ethrotate - When set to "no" U-Boot does not go through all
3720 available network interfaces.
3721 It just stays at the currently selected interface.
3723 netretry - When set to "no" each network operation will
3724 either succeed or fail without retrying.
3725 When set to "once" the network operation will
3726 fail when all the available network interfaces
3727 are tried once without success.
3728 Useful on scripts which control the retry operation
3731 npe_ucode - set load address for the NPE microcode
3733 tftpsrcport - If this is set, the value is used for TFTP's
3736 tftpdstport - If this is set, the value is used for TFTP's UDP
3737 destination port instead of the Well Know Port 69.
3739 tftpblocksize - Block size to use for TFTP transfers; if not set,
3740 we use the TFTP server's default block size
3742 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3743 seconds, minimum value is 1000 = 1 second). Defines
3744 when a packet is considered to be lost so it has to
3745 be retransmitted. The default is 5000 = 5 seconds.
3746 Lowering this value may make downloads succeed
3747 faster in networks with high packet loss rates or
3748 with unreliable TFTP servers.
3750 vlan - When set to a value < 4095 the traffic over
3751 Ethernet is encapsulated/received over 802.1q
3754 The following image location variables contain the location of images
3755 used in booting. The "Image" column gives the role of the image and is
3756 not an environment variable name. The other columns are environment
3757 variable names. "File Name" gives the name of the file on a TFTP
3758 server, "RAM Address" gives the location in RAM the image will be
3759 loaded to, and "Flash Location" gives the image's address in NOR
3760 flash or offset in NAND flash.
3762 *Note* - these variables don't have to be defined for all boards, some
3763 boards currenlty use other variables for these purposes, and some
3764 boards use these variables for other purposes.
3766 Image File Name RAM Address Flash Location
3767 ----- --------- ----------- --------------
3768 u-boot u-boot u-boot_addr_r u-boot_addr
3769 Linux kernel bootfile kernel_addr_r kernel_addr
3770 device tree blob fdtfile fdt_addr_r fdt_addr
3771 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3773 The following environment variables may be used and automatically
3774 updated by the network boot commands ("bootp" and "rarpboot"),
3775 depending the information provided by your boot server:
3777 bootfile - see above
3778 dnsip - IP address of your Domain Name Server
3779 dnsip2 - IP address of your secondary Domain Name Server
3780 gatewayip - IP address of the Gateway (Router) to use
3781 hostname - Target hostname
3783 netmask - Subnet Mask
3784 rootpath - Pathname of the root filesystem on the NFS server
3785 serverip - see above
3788 There are two special Environment Variables:
3790 serial# - contains hardware identification information such
3791 as type string and/or serial number
3792 ethaddr - Ethernet address
3794 These variables can be set only once (usually during manufacturing of
3795 the board). U-Boot refuses to delete or overwrite these variables
3796 once they have been set once.
3799 Further special Environment Variables:
3801 ver - Contains the U-Boot version string as printed
3802 with the "version" command. This variable is
3803 readonly (see CONFIG_VERSION_VARIABLE).
3806 Please note that changes to some configuration parameters may take
3807 only effect after the next boot (yes, that's just like Windoze :-).
3810 Command Line Parsing:
3811 =====================
3813 There are two different command line parsers available with U-Boot:
3814 the old "simple" one, and the much more powerful "hush" shell:
3816 Old, simple command line parser:
3817 --------------------------------
3819 - supports environment variables (through setenv / saveenv commands)
3820 - several commands on one line, separated by ';'
3821 - variable substitution using "... ${name} ..." syntax
3822 - special characters ('$', ';') can be escaped by prefixing with '\',
3824 setenv bootcmd bootm \${address}
3825 - You can also escape text by enclosing in single apostrophes, for example:
3826 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3831 - similar to Bourne shell, with control structures like
3832 if...then...else...fi, for...do...done; while...do...done,
3833 until...do...done, ...
3834 - supports environment ("global") variables (through setenv / saveenv
3835 commands) and local shell variables (through standard shell syntax
3836 "name=value"); only environment variables can be used with "run"
3842 (1) If a command line (or an environment variable executed by a "run"
3843 command) contains several commands separated by semicolon, and
3844 one of these commands fails, then the remaining commands will be
3847 (2) If you execute several variables with one call to run (i. e.
3848 calling run with a list of variables as arguments), any failing
3849 command will cause "run" to terminate, i. e. the remaining
3850 variables are not executed.
3852 Note for Redundant Ethernet Interfaces:
3853 =======================================
3855 Some boards come with redundant Ethernet interfaces; U-Boot supports
3856 such configurations and is capable of automatic selection of a
3857 "working" interface when needed. MAC assignment works as follows:
3859 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3860 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3861 "eth1addr" (=>eth1), "eth2addr", ...
3863 If the network interface stores some valid MAC address (for instance
3864 in SROM), this is used as default address if there is NO correspon-
3865 ding setting in the environment; if the corresponding environment
3866 variable is set, this overrides the settings in the card; that means:
3868 o If the SROM has a valid MAC address, and there is no address in the
3869 environment, the SROM's address is used.
3871 o If there is no valid address in the SROM, and a definition in the
3872 environment exists, then the value from the environment variable is
3875 o If both the SROM and the environment contain a MAC address, and
3876 both addresses are the same, this MAC address is used.
3878 o If both the SROM and the environment contain a MAC address, and the
3879 addresses differ, the value from the environment is used and a
3882 o If neither SROM nor the environment contain a MAC address, an error
3885 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3886 will be programmed into hardware as part of the initialization process. This
3887 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3888 The naming convention is as follows:
3889 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3894 U-Boot is capable of booting (and performing other auxiliary operations on)
3895 images in two formats:
3897 New uImage format (FIT)
3898 -----------------------
3900 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3901 to Flattened Device Tree). It allows the use of images with multiple
3902 components (several kernels, ramdisks, etc.), with contents protected by
3903 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3909 Old image format is based on binary files which can be basically anything,
3910 preceded by a special header; see the definitions in include/image.h for
3911 details; basically, the header defines the following image properties:
3913 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3914 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3915 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3916 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3918 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3919 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3920 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3921 * Compression Type (uncompressed, gzip, bzip2)
3927 The header is marked by a special Magic Number, and both the header
3928 and the data portions of the image are secured against corruption by
3935 Although U-Boot should support any OS or standalone application
3936 easily, the main focus has always been on Linux during the design of
3939 U-Boot includes many features that so far have been part of some
3940 special "boot loader" code within the Linux kernel. Also, any
3941 "initrd" images to be used are no longer part of one big Linux image;
3942 instead, kernel and "initrd" are separate images. This implementation
3943 serves several purposes:
3945 - the same features can be used for other OS or standalone
3946 applications (for instance: using compressed images to reduce the
3947 Flash memory footprint)
3949 - it becomes much easier to port new Linux kernel versions because
3950 lots of low-level, hardware dependent stuff are done by U-Boot
3952 - the same Linux kernel image can now be used with different "initrd"
3953 images; of course this also means that different kernel images can
3954 be run with the same "initrd". This makes testing easier (you don't
3955 have to build a new "zImage.initrd" Linux image when you just
3956 change a file in your "initrd"). Also, a field-upgrade of the
3957 software is easier now.
3963 Porting Linux to U-Boot based systems:
3964 ---------------------------------------
3966 U-Boot cannot save you from doing all the necessary modifications to
3967 configure the Linux device drivers for use with your target hardware
3968 (no, we don't intend to provide a full virtual machine interface to
3971 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3973 Just make sure your machine specific header file (for instance
3974 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3975 Information structure as we define in include/asm-<arch>/u-boot.h,
3976 and make sure that your definition of IMAP_ADDR uses the same value
3977 as your U-Boot configuration in CONFIG_SYS_IMMR.
3980 Configuring the Linux kernel:
3981 -----------------------------
3983 No specific requirements for U-Boot. Make sure you have some root
3984 device (initial ramdisk, NFS) for your target system.
3987 Building a Linux Image:
3988 -----------------------
3990 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3991 not used. If you use recent kernel source, a new build target
3992 "uImage" will exist which automatically builds an image usable by
3993 U-Boot. Most older kernels also have support for a "pImage" target,
3994 which was introduced for our predecessor project PPCBoot and uses a
3995 100% compatible format.
4004 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4005 encapsulate a compressed Linux kernel image with header information,
4006 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4008 * build a standard "vmlinux" kernel image (in ELF binary format):
4010 * convert the kernel into a raw binary image:
4012 ${CROSS_COMPILE}-objcopy -O binary \
4013 -R .note -R .comment \
4014 -S vmlinux linux.bin
4016 * compress the binary image:
4020 * package compressed binary image for U-Boot:
4022 mkimage -A ppc -O linux -T kernel -C gzip \
4023 -a 0 -e 0 -n "Linux Kernel Image" \
4024 -d linux.bin.gz uImage
4027 The "mkimage" tool can also be used to create ramdisk images for use
4028 with U-Boot, either separated from the Linux kernel image, or
4029 combined into one file. "mkimage" encapsulates the images with a 64
4030 byte header containing information about target architecture,
4031 operating system, image type, compression method, entry points, time
4032 stamp, CRC32 checksums, etc.
4034 "mkimage" can be called in two ways: to verify existing images and
4035 print the header information, or to build new images.
4037 In the first form (with "-l" option) mkimage lists the information
4038 contained in the header of an existing U-Boot image; this includes
4039 checksum verification:
4041 tools/mkimage -l image
4042 -l ==> list image header information
4044 The second form (with "-d" option) is used to build a U-Boot image
4045 from a "data file" which is used as image payload:
4047 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4048 -n name -d data_file image
4049 -A ==> set architecture to 'arch'
4050 -O ==> set operating system to 'os'
4051 -T ==> set image type to 'type'
4052 -C ==> set compression type 'comp'
4053 -a ==> set load address to 'addr' (hex)
4054 -e ==> set entry point to 'ep' (hex)
4055 -n ==> set image name to 'name'
4056 -d ==> use image data from 'datafile'
4058 Right now, all Linux kernels for PowerPC systems use the same load
4059 address (0x00000000), but the entry point address depends on the
4062 - 2.2.x kernels have the entry point at 0x0000000C,
4063 - 2.3.x and later kernels have the entry point at 0x00000000.
4065 So a typical call to build a U-Boot image would read:
4067 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4068 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4069 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4070 > examples/uImage.TQM850L
4071 Image Name: 2.4.4 kernel for TQM850L
4072 Created: Wed Jul 19 02:34:59 2000
4073 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4074 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4075 Load Address: 0x00000000
4076 Entry Point: 0x00000000
4078 To verify the contents of the image (or check for corruption):
4080 -> tools/mkimage -l examples/uImage.TQM850L
4081 Image Name: 2.4.4 kernel for TQM850L
4082 Created: Wed Jul 19 02:34:59 2000
4083 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4084 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4085 Load Address: 0x00000000
4086 Entry Point: 0x00000000
4088 NOTE: for embedded systems where boot time is critical you can trade
4089 speed for memory and install an UNCOMPRESSED image instead: this
4090 needs more space in Flash, but boots much faster since it does not
4091 need to be uncompressed:
4093 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4094 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4095 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4096 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4097 > examples/uImage.TQM850L-uncompressed
4098 Image Name: 2.4.4 kernel for TQM850L
4099 Created: Wed Jul 19 02:34:59 2000
4100 Image Type: PowerPC Linux Kernel Image (uncompressed)
4101 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4102 Load Address: 0x00000000
4103 Entry Point: 0x00000000
4106 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4107 when your kernel is intended to use an initial ramdisk:
4109 -> tools/mkimage -n 'Simple Ramdisk Image' \
4110 > -A ppc -O linux -T ramdisk -C gzip \
4111 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4112 Image Name: Simple Ramdisk Image
4113 Created: Wed Jan 12 14:01:50 2000
4114 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4115 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4116 Load Address: 0x00000000
4117 Entry Point: 0x00000000
4120 Installing a Linux Image:
4121 -------------------------
4123 To downloading a U-Boot image over the serial (console) interface,
4124 you must convert the image to S-Record format:
4126 objcopy -I binary -O srec examples/image examples/image.srec
4128 The 'objcopy' does not understand the information in the U-Boot
4129 image header, so the resulting S-Record file will be relative to
4130 address 0x00000000. To load it to a given address, you need to
4131 specify the target address as 'offset' parameter with the 'loads'
4134 Example: install the image to address 0x40100000 (which on the
4135 TQM8xxL is in the first Flash bank):
4137 => erase 40100000 401FFFFF
4143 ## Ready for S-Record download ...
4144 ~>examples/image.srec
4145 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4147 15989 15990 15991 15992
4148 [file transfer complete]
4150 ## Start Addr = 0x00000000
4153 You can check the success of the download using the 'iminfo' command;
4154 this includes a checksum verification so you can be sure no data
4155 corruption happened:
4159 ## Checking Image at 40100000 ...
4160 Image Name: 2.2.13 for initrd on TQM850L
4161 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4162 Data Size: 335725 Bytes = 327 kB = 0 MB
4163 Load Address: 00000000
4164 Entry Point: 0000000c
4165 Verifying Checksum ... OK
4171 The "bootm" command is used to boot an application that is stored in
4172 memory (RAM or Flash). In case of a Linux kernel image, the contents
4173 of the "bootargs" environment variable is passed to the kernel as
4174 parameters. You can check and modify this variable using the
4175 "printenv" and "setenv" commands:
4178 => printenv bootargs
4179 bootargs=root=/dev/ram
4181 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4183 => printenv bootargs
4184 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4187 ## Booting Linux kernel at 40020000 ...
4188 Image Name: 2.2.13 for NFS on TQM850L
4189 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4190 Data Size: 381681 Bytes = 372 kB = 0 MB
4191 Load Address: 00000000
4192 Entry Point: 0000000c
4193 Verifying Checksum ... OK
4194 Uncompressing Kernel Image ... OK
4195 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
4196 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4197 time_init: decrementer frequency = 187500000/60
4198 Calibrating delay loop... 49.77 BogoMIPS
4199 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4202 If you want to boot a Linux kernel with initial RAM disk, you pass
4203 the memory addresses of both the kernel and the initrd image (PPBCOOT
4204 format!) to the "bootm" command:
4206 => imi 40100000 40200000
4208 ## Checking Image at 40100000 ...
4209 Image Name: 2.2.13 for initrd on TQM850L
4210 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4211 Data Size: 335725 Bytes = 327 kB = 0 MB
4212 Load Address: 00000000
4213 Entry Point: 0000000c
4214 Verifying Checksum ... OK
4216 ## Checking Image at 40200000 ...
4217 Image Name: Simple Ramdisk Image
4218 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4219 Data Size: 566530 Bytes = 553 kB = 0 MB
4220 Load Address: 00000000
4221 Entry Point: 00000000
4222 Verifying Checksum ... OK
4224 => bootm 40100000 40200000
4225 ## Booting Linux kernel at 40100000 ...
4226 Image Name: 2.2.13 for initrd on TQM850L
4227 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4228 Data Size: 335725 Bytes = 327 kB = 0 MB
4229 Load Address: 00000000
4230 Entry Point: 0000000c
4231 Verifying Checksum ... OK
4232 Uncompressing Kernel Image ... OK
4233 ## Loading RAMDisk Image at 40200000 ...
4234 Image Name: Simple Ramdisk Image
4235 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4236 Data Size: 566530 Bytes = 553 kB = 0 MB
4237 Load Address: 00000000
4238 Entry Point: 00000000
4239 Verifying Checksum ... OK
4240 Loading Ramdisk ... OK
4241 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
4242 Boot arguments: root=/dev/ram
4243 time_init: decrementer frequency = 187500000/60
4244 Calibrating delay loop... 49.77 BogoMIPS
4246 RAMDISK: Compressed image found at block 0
4247 VFS: Mounted root (ext2 filesystem).
4251 Boot Linux and pass a flat device tree:
4254 First, U-Boot must be compiled with the appropriate defines. See the section
4255 titled "Linux Kernel Interface" above for a more in depth explanation. The
4256 following is an example of how to start a kernel and pass an updated
4262 oft=oftrees/mpc8540ads.dtb
4263 => tftp $oftaddr $oft
4264 Speed: 1000, full duplex
4266 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4267 Filename 'oftrees/mpc8540ads.dtb'.
4268 Load address: 0x300000
4271 Bytes transferred = 4106 (100a hex)
4272 => tftp $loadaddr $bootfile
4273 Speed: 1000, full duplex
4275 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4277 Load address: 0x200000
4278 Loading:############
4280 Bytes transferred = 1029407 (fb51f hex)
4285 => bootm $loadaddr - $oftaddr
4286 ## Booting image at 00200000 ...
4287 Image Name: Linux-2.6.17-dirty
4288 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4289 Data Size: 1029343 Bytes = 1005.2 kB
4290 Load Address: 00000000
4291 Entry Point: 00000000
4292 Verifying Checksum ... OK
4293 Uncompressing Kernel Image ... OK
4294 Booting using flat device tree at 0x300000
4295 Using MPC85xx ADS machine description
4296 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4300 More About U-Boot Image Types:
4301 ------------------------------
4303 U-Boot supports the following image types:
4305 "Standalone Programs" are directly runnable in the environment
4306 provided by U-Boot; it is expected that (if they behave
4307 well) you can continue to work in U-Boot after return from
4308 the Standalone Program.
4309 "OS Kernel Images" are usually images of some Embedded OS which
4310 will take over control completely. Usually these programs
4311 will install their own set of exception handlers, device
4312 drivers, set up the MMU, etc. - this means, that you cannot
4313 expect to re-enter U-Boot except by resetting the CPU.
4314 "RAMDisk Images" are more or less just data blocks, and their
4315 parameters (address, size) are passed to an OS kernel that is
4317 "Multi-File Images" contain several images, typically an OS
4318 (Linux) kernel image and one or more data images like
4319 RAMDisks. This construct is useful for instance when you want
4320 to boot over the network using BOOTP etc., where the boot
4321 server provides just a single image file, but you want to get
4322 for instance an OS kernel and a RAMDisk image.
4324 "Multi-File Images" start with a list of image sizes, each
4325 image size (in bytes) specified by an "uint32_t" in network
4326 byte order. This list is terminated by an "(uint32_t)0".
4327 Immediately after the terminating 0 follow the images, one by
4328 one, all aligned on "uint32_t" boundaries (size rounded up to
4329 a multiple of 4 bytes).
4331 "Firmware Images" are binary images containing firmware (like
4332 U-Boot or FPGA images) which usually will be programmed to
4335 "Script files" are command sequences that will be executed by
4336 U-Boot's command interpreter; this feature is especially
4337 useful when you configure U-Boot to use a real shell (hush)
4338 as command interpreter.
4344 One of the features of U-Boot is that you can dynamically load and
4345 run "standalone" applications, which can use some resources of
4346 U-Boot like console I/O functions or interrupt services.
4348 Two simple examples are included with the sources:
4353 'examples/hello_world.c' contains a small "Hello World" Demo
4354 application; it is automatically compiled when you build U-Boot.
4355 It's configured to run at address 0x00040004, so you can play with it
4359 ## Ready for S-Record download ...
4360 ~>examples/hello_world.srec
4361 1 2 3 4 5 6 7 8 9 10 11 ...
4362 [file transfer complete]
4364 ## Start Addr = 0x00040004
4366 => go 40004 Hello World! This is a test.
4367 ## Starting application at 0x00040004 ...
4378 Hit any key to exit ...
4380 ## Application terminated, rc = 0x0
4382 Another example, which demonstrates how to register a CPM interrupt
4383 handler with the U-Boot code, can be found in 'examples/timer.c'.
4384 Here, a CPM timer is set up to generate an interrupt every second.
4385 The interrupt service routine is trivial, just printing a '.'
4386 character, but this is just a demo program. The application can be
4387 controlled by the following keys:
4389 ? - print current values og the CPM Timer registers
4390 b - enable interrupts and start timer
4391 e - stop timer and disable interrupts
4392 q - quit application
4395 ## Ready for S-Record download ...
4396 ~>examples/timer.srec
4397 1 2 3 4 5 6 7 8 9 10 11 ...
4398 [file transfer complete]
4400 ## Start Addr = 0x00040004
4403 ## Starting application at 0x00040004 ...
4406 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4409 [q, b, e, ?] Set interval 1000000 us
4412 [q, b, e, ?] ........
4413 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4416 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4419 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4422 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4424 [q, b, e, ?] ...Stopping timer
4426 [q, b, e, ?] ## Application terminated, rc = 0x0
4432 Over time, many people have reported problems when trying to use the
4433 "minicom" terminal emulation program for serial download. I (wd)
4434 consider minicom to be broken, and recommend not to use it. Under
4435 Unix, I recommend to use C-Kermit for general purpose use (and
4436 especially for kermit binary protocol download ("loadb" command), and
4437 use "cu" for S-Record download ("loads" command).
4439 Nevertheless, if you absolutely want to use it try adding this
4440 configuration to your "File transfer protocols" section:
4442 Name Program Name U/D FullScr IO-Red. Multi
4443 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4444 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4450 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4451 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4453 Building requires a cross environment; it is known to work on
4454 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4455 need gmake since the Makefiles are not compatible with BSD make).
4456 Note that the cross-powerpc package does not install include files;
4457 attempting to build U-Boot will fail because <machine/ansi.h> is
4458 missing. This file has to be installed and patched manually:
4460 # cd /usr/pkg/cross/powerpc-netbsd/include
4462 # ln -s powerpc machine
4463 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4464 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4466 Native builds *don't* work due to incompatibilities between native
4467 and U-Boot include files.
4469 Booting assumes that (the first part of) the image booted is a
4470 stage-2 loader which in turn loads and then invokes the kernel
4471 proper. Loader sources will eventually appear in the NetBSD source
4472 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4473 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4476 Implementation Internals:
4477 =========================
4479 The following is not intended to be a complete description of every
4480 implementation detail. However, it should help to understand the
4481 inner workings of U-Boot and make it easier to port it to custom
4485 Initial Stack, Global Data:
4486 ---------------------------
4488 The implementation of U-Boot is complicated by the fact that U-Boot
4489 starts running out of ROM (flash memory), usually without access to
4490 system RAM (because the memory controller is not initialized yet).
4491 This means that we don't have writable Data or BSS segments, and BSS
4492 is not initialized as zero. To be able to get a C environment working
4493 at all, we have to allocate at least a minimal stack. Implementation
4494 options for this are defined and restricted by the CPU used: Some CPU
4495 models provide on-chip memory (like the IMMR area on MPC8xx and
4496 MPC826x processors), on others (parts of) the data cache can be
4497 locked as (mis-) used as memory, etc.
4499 Chris Hallinan posted a good summary of these issues to the
4500 U-Boot mailing list:
4502 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4503 From: "Chris Hallinan" <clh@net1plus.com>
4504 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4507 Correct me if I'm wrong, folks, but the way I understand it
4508 is this: Using DCACHE as initial RAM for Stack, etc, does not
4509 require any physical RAM backing up the cache. The cleverness
4510 is that the cache is being used as a temporary supply of
4511 necessary storage before the SDRAM controller is setup. It's
4512 beyond the scope of this list to explain the details, but you
4513 can see how this works by studying the cache architecture and
4514 operation in the architecture and processor-specific manuals.
4516 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4517 is another option for the system designer to use as an
4518 initial stack/RAM area prior to SDRAM being available. Either
4519 option should work for you. Using CS 4 should be fine if your
4520 board designers haven't used it for something that would
4521 cause you grief during the initial boot! It is frequently not
4524 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4525 with your processor/board/system design. The default value
4526 you will find in any recent u-boot distribution in
4527 walnut.h should work for you. I'd set it to a value larger
4528 than your SDRAM module. If you have a 64MB SDRAM module, set
4529 it above 400_0000. Just make sure your board has no resources
4530 that are supposed to respond to that address! That code in
4531 start.S has been around a while and should work as is when
4532 you get the config right.
4537 It is essential to remember this, since it has some impact on the C
4538 code for the initialization procedures:
4540 * Initialized global data (data segment) is read-only. Do not attempt
4543 * Do not use any uninitialized global data (or implicitely initialized
4544 as zero data - BSS segment) at all - this is undefined, initiali-
4545 zation is performed later (when relocating to RAM).
4547 * Stack space is very limited. Avoid big data buffers or things like
4550 Having only the stack as writable memory limits means we cannot use
4551 normal global data to share information beween the code. But it
4552 turned out that the implementation of U-Boot can be greatly
4553 simplified by making a global data structure (gd_t) available to all
4554 functions. We could pass a pointer to this data as argument to _all_
4555 functions, but this would bloat the code. Instead we use a feature of
4556 the GCC compiler (Global Register Variables) to share the data: we
4557 place a pointer (gd) to the global data into a register which we
4558 reserve for this purpose.
4560 When choosing a register for such a purpose we are restricted by the
4561 relevant (E)ABI specifications for the current architecture, and by
4562 GCC's implementation.
4564 For PowerPC, the following registers have specific use:
4566 R2: reserved for system use
4567 R3-R4: parameter passing and return values
4568 R5-R10: parameter passing
4569 R13: small data area pointer
4573 (U-Boot also uses R12 as internal GOT pointer. r12
4574 is a volatile register so r12 needs to be reset when
4575 going back and forth between asm and C)
4577 ==> U-Boot will use R2 to hold a pointer to the global data
4579 Note: on PPC, we could use a static initializer (since the
4580 address of the global data structure is known at compile time),
4581 but it turned out that reserving a register results in somewhat
4582 smaller code - although the code savings are not that big (on
4583 average for all boards 752 bytes for the whole U-Boot image,
4584 624 text + 127 data).
4586 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4587 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4589 ==> U-Boot will use P3 to hold a pointer to the global data
4591 On ARM, the following registers are used:
4593 R0: function argument word/integer result
4594 R1-R3: function argument word
4596 R10: stack limit (used only if stack checking if enabled)
4597 R11: argument (frame) pointer
4598 R12: temporary workspace
4601 R15: program counter
4603 ==> U-Boot will use R8 to hold a pointer to the global data
4605 On Nios II, the ABI is documented here:
4606 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4608 ==> U-Boot will use gp to hold a pointer to the global data
4610 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4611 to access small data sections, so gp is free.
4613 On NDS32, the following registers are used:
4615 R0-R1: argument/return
4617 R15: temporary register for assembler
4618 R16: trampoline register
4619 R28: frame pointer (FP)
4620 R29: global pointer (GP)
4621 R30: link register (LP)
4622 R31: stack pointer (SP)
4623 PC: program counter (PC)
4625 ==> U-Boot will use R10 to hold a pointer to the global data
4627 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4628 or current versions of GCC may "optimize" the code too much.
4633 U-Boot runs in system state and uses physical addresses, i.e. the
4634 MMU is not used either for address mapping nor for memory protection.
4636 The available memory is mapped to fixed addresses using the memory
4637 controller. In this process, a contiguous block is formed for each
4638 memory type (Flash, SDRAM, SRAM), even when it consists of several
4639 physical memory banks.
4641 U-Boot is installed in the first 128 kB of the first Flash bank (on
4642 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4643 booting and sizing and initializing DRAM, the code relocates itself
4644 to the upper end of DRAM. Immediately below the U-Boot code some
4645 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4646 configuration setting]. Below that, a structure with global Board
4647 Info data is placed, followed by the stack (growing downward).
4649 Additionally, some exception handler code is copied to the low 8 kB
4650 of DRAM (0x00000000 ... 0x00001FFF).
4652 So a typical memory configuration with 16 MB of DRAM could look like
4655 0x0000 0000 Exception Vector code
4658 0x0000 2000 Free for Application Use
4664 0x00FB FF20 Monitor Stack (Growing downward)
4665 0x00FB FFAC Board Info Data and permanent copy of global data
4666 0x00FC 0000 Malloc Arena
4669 0x00FE 0000 RAM Copy of Monitor Code
4670 ... eventually: LCD or video framebuffer
4671 ... eventually: pRAM (Protected RAM - unchanged by reset)
4672 0x00FF FFFF [End of RAM]
4675 System Initialization:
4676 ----------------------
4678 In the reset configuration, U-Boot starts at the reset entry point
4679 (on most PowerPC systems at address 0x00000100). Because of the reset
4680 configuration for CS0# this is a mirror of the onboard Flash memory.
4681 To be able to re-map memory U-Boot then jumps to its link address.
4682 To be able to implement the initialization code in C, a (small!)
4683 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4684 which provide such a feature like MPC8xx or MPC8260), or in a locked
4685 part of the data cache. After that, U-Boot initializes the CPU core,
4686 the caches and the SIU.
4688 Next, all (potentially) available memory banks are mapped using a
4689 preliminary mapping. For example, we put them on 512 MB boundaries
4690 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4691 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4692 programmed for SDRAM access. Using the temporary configuration, a
4693 simple memory test is run that determines the size of the SDRAM
4696 When there is more than one SDRAM bank, and the banks are of
4697 different size, the largest is mapped first. For equal size, the first
4698 bank (CS2#) is mapped first. The first mapping is always for address
4699 0x00000000, with any additional banks following immediately to create
4700 contiguous memory starting from 0.
4702 Then, the monitor installs itself at the upper end of the SDRAM area
4703 and allocates memory for use by malloc() and for the global Board
4704 Info data; also, the exception vector code is copied to the low RAM
4705 pages, and the final stack is set up.
4707 Only after this relocation will you have a "normal" C environment;
4708 until that you are restricted in several ways, mostly because you are
4709 running from ROM, and because the code will have to be relocated to a
4713 U-Boot Porting Guide:
4714 ----------------------
4716 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4720 int main(int argc, char *argv[])
4722 sighandler_t no_more_time;
4724 signal(SIGALRM, no_more_time);
4725 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4727 if (available_money > available_manpower) {
4728 Pay consultant to port U-Boot;
4732 Download latest U-Boot source;
4734 Subscribe to u-boot mailing list;
4737 email("Hi, I am new to U-Boot, how do I get started?");
4740 Read the README file in the top level directory;
4741 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4742 Read applicable doc/*.README;
4743 Read the source, Luke;
4744 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4747 if (available_money > toLocalCurrency ($2500))
4750 Add a lot of aggravation and time;
4752 if (a similar board exists) { /* hopefully... */
4753 cp -a board/<similar> board/<myboard>
4754 cp include/configs/<similar>.h include/configs/<myboard>.h
4756 Create your own board support subdirectory;
4757 Create your own board include/configs/<myboard>.h file;
4759 Edit new board/<myboard> files
4760 Edit new include/configs/<myboard>.h
4765 Add / modify source code;
4769 email("Hi, I am having problems...");
4771 Send patch file to the U-Boot email list;
4772 if (reasonable critiques)
4773 Incorporate improvements from email list code review;
4775 Defend code as written;
4781 void no_more_time (int sig)
4790 All contributions to U-Boot should conform to the Linux kernel
4791 coding style; see the file "Documentation/CodingStyle" and the script
4792 "scripts/Lindent" in your Linux kernel source directory.
4794 Source files originating from a different project (for example the
4795 MTD subsystem) are generally exempt from these guidelines and are not
4796 reformated to ease subsequent migration to newer versions of those
4799 Please note that U-Boot is implemented in C (and to some small parts in
4800 Assembler); no C++ is used, so please do not use C++ style comments (//)
4803 Please also stick to the following formatting rules:
4804 - remove any trailing white space
4805 - use TAB characters for indentation and vertical alignment, not spaces
4806 - make sure NOT to use DOS '\r\n' line feeds
4807 - do not add more than 2 consecutive empty lines to source files
4808 - do not add trailing empty lines to source files
4810 Submissions which do not conform to the standards may be returned
4811 with a request to reformat the changes.
4817 Since the number of patches for U-Boot is growing, we need to
4818 establish some rules. Submissions which do not conform to these rules
4819 may be rejected, even when they contain important and valuable stuff.
4821 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4823 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4824 see http://lists.denx.de/mailman/listinfo/u-boot
4826 When you send a patch, please include the following information with
4829 * For bug fixes: a description of the bug and how your patch fixes
4830 this bug. Please try to include a way of demonstrating that the
4831 patch actually fixes something.
4833 * For new features: a description of the feature and your
4836 * A CHANGELOG entry as plaintext (separate from the patch)
4838 * For major contributions, your entry to the CREDITS file
4840 * When you add support for a new board, don't forget to add this
4841 board to the MAINTAINERS file, too.
4843 * If your patch adds new configuration options, don't forget to
4844 document these in the README file.
4846 * The patch itself. If you are using git (which is *strongly*
4847 recommended) you can easily generate the patch using the
4848 "git format-patch". If you then use "git send-email" to send it to
4849 the U-Boot mailing list, you will avoid most of the common problems
4850 with some other mail clients.
4852 If you cannot use git, use "diff -purN OLD NEW". If your version of
4853 diff does not support these options, then get the latest version of
4856 The current directory when running this command shall be the parent
4857 directory of the U-Boot source tree (i. e. please make sure that
4858 your patch includes sufficient directory information for the
4861 We prefer patches as plain text. MIME attachments are discouraged,
4862 and compressed attachments must not be used.
4864 * If one logical set of modifications affects or creates several
4865 files, all these changes shall be submitted in a SINGLE patch file.
4867 * Changesets that contain different, unrelated modifications shall be
4868 submitted as SEPARATE patches, one patch per changeset.
4873 * Before sending the patch, run the MAKEALL script on your patched
4874 source tree and make sure that no errors or warnings are reported
4875 for any of the boards.
4877 * Keep your modifications to the necessary minimum: A patch
4878 containing several unrelated changes or arbitrary reformats will be
4879 returned with a request to re-formatting / split it.
4881 * If you modify existing code, make sure that your new code does not
4882 add to the memory footprint of the code ;-) Small is beautiful!
4883 When adding new features, these should compile conditionally only
4884 (using #ifdef), and the resulting code with the new feature
4885 disabled must not need more memory than the old code without your
4888 * Remember that there is a size limit of 100 kB per message on the
4889 u-boot mailing list. Bigger patches will be moderated. If they are
4890 reasonable and not too big, they will be acknowledged. But patches
4891 bigger than the size limit should be avoided.