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 - Safe printf() functions
648 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
649 the printf() functions. These are defined in
650 include/vsprintf.h and include snprintf(), vsnprintf() and
651 so on. Code size increase is approximately 300-500 bytes.
652 If this option is not given then these functions will
653 silently discard their buffer size argument - this means
654 you are not getting any overflow checking in this case.
656 - Boot Delay: CONFIG_BOOTDELAY - in seconds
657 Delay before automatically booting the default image;
658 set to -1 to disable autoboot.
660 See doc/README.autoboot for these options that
661 work with CONFIG_BOOTDELAY. None are required.
662 CONFIG_BOOT_RETRY_TIME
663 CONFIG_BOOT_RETRY_MIN
664 CONFIG_AUTOBOOT_KEYED
665 CONFIG_AUTOBOOT_PROMPT
666 CONFIG_AUTOBOOT_DELAY_STR
667 CONFIG_AUTOBOOT_STOP_STR
668 CONFIG_AUTOBOOT_DELAY_STR2
669 CONFIG_AUTOBOOT_STOP_STR2
670 CONFIG_ZERO_BOOTDELAY_CHECK
671 CONFIG_RESET_TO_RETRY
675 Only needed when CONFIG_BOOTDELAY is enabled;
676 define a command string that is automatically executed
677 when no character is read on the console interface
678 within "Boot Delay" after reset.
681 This can be used to pass arguments to the bootm
682 command. The value of CONFIG_BOOTARGS goes into the
683 environment value "bootargs".
685 CONFIG_RAMBOOT and CONFIG_NFSBOOT
686 The value of these goes into the environment as
687 "ramboot" and "nfsboot" respectively, and can be used
688 as a convenience, when switching between booting from
694 When this option is #defined, the existence of the
695 environment variable "preboot" will be checked
696 immediately before starting the CONFIG_BOOTDELAY
697 countdown and/or running the auto-boot command resp.
698 entering interactive mode.
700 This feature is especially useful when "preboot" is
701 automatically generated or modified. For an example
702 see the LWMON board specific code: here "preboot" is
703 modified when the user holds down a certain
704 combination of keys on the (special) keyboard when
707 - Serial Download Echo Mode:
709 If defined to 1, all characters received during a
710 serial download (using the "loads" command) are
711 echoed back. This might be needed by some terminal
712 emulations (like "cu"), but may as well just take
713 time on others. This setting #define's the initial
714 value of the "loads_echo" environment variable.
716 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
718 Select one of the baudrates listed in
719 CONFIG_SYS_BAUDRATE_TABLE, see below.
722 Monitor commands can be included or excluded
723 from the build by using the #include files
724 "config_cmd_all.h" and #undef'ing unwanted
725 commands, or using "config_cmd_default.h"
726 and augmenting with additional #define's
729 The default command configuration includes all commands
730 except those marked below with a "*".
732 CONFIG_CMD_ASKENV * ask for env variable
733 CONFIG_CMD_BDI bdinfo
734 CONFIG_CMD_BEDBUG * Include BedBug Debugger
735 CONFIG_CMD_BMP * BMP support
736 CONFIG_CMD_BSP * Board specific commands
737 CONFIG_CMD_BOOTD bootd
738 CONFIG_CMD_CACHE * icache, dcache
739 CONFIG_CMD_CONSOLE coninfo
740 CONFIG_CMD_CRC32 * crc32
741 CONFIG_CMD_DATE * support for RTC, date/time...
742 CONFIG_CMD_DHCP * DHCP support
743 CONFIG_CMD_DIAG * Diagnostics
744 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
745 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
746 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
747 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
748 CONFIG_CMD_DTT * Digital Therm and Thermostat
749 CONFIG_CMD_ECHO echo arguments
750 CONFIG_CMD_EDITENV edit env variable
751 CONFIG_CMD_EEPROM * EEPROM read/write support
752 CONFIG_CMD_ELF * bootelf, bootvx
753 CONFIG_CMD_EXPORTENV * export the environment
754 CONFIG_CMD_SAVEENV saveenv
755 CONFIG_CMD_FDC * Floppy Disk Support
756 CONFIG_CMD_FAT * FAT partition support
757 CONFIG_CMD_FDOS * Dos diskette Support
758 CONFIG_CMD_FLASH flinfo, erase, protect
759 CONFIG_CMD_FPGA FPGA device initialization support
760 CONFIG_CMD_GO * the 'go' command (exec code)
761 CONFIG_CMD_GREPENV * search environment
762 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
763 CONFIG_CMD_I2C * I2C serial bus support
764 CONFIG_CMD_IDE * IDE harddisk support
765 CONFIG_CMD_IMI iminfo
766 CONFIG_CMD_IMLS List all found images
767 CONFIG_CMD_IMMAP * IMMR dump support
768 CONFIG_CMD_IMPORTENV * import an environment
769 CONFIG_CMD_IRQ * irqinfo
770 CONFIG_CMD_ITEST Integer/string test of 2 values
771 CONFIG_CMD_JFFS2 * JFFS2 Support
772 CONFIG_CMD_KGDB * kgdb
773 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
774 CONFIG_CMD_LOADB loadb
775 CONFIG_CMD_LOADS loads
776 CONFIG_CMD_MD5SUM print md5 message digest
777 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
778 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
780 CONFIG_CMD_MISC Misc functions like sleep etc
781 CONFIG_CMD_MMC * MMC memory mapped support
782 CONFIG_CMD_MII * MII utility commands
783 CONFIG_CMD_MTDPARTS * MTD partition support
784 CONFIG_CMD_NAND * NAND support
785 CONFIG_CMD_NET bootp, tftpboot, rarpboot
786 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
787 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
788 CONFIG_CMD_PCI * pciinfo
789 CONFIG_CMD_PCMCIA * PCMCIA support
790 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
792 CONFIG_CMD_PORTIO * Port I/O
793 CONFIG_CMD_REGINFO * Register dump
794 CONFIG_CMD_RUN run command in env variable
795 CONFIG_CMD_SAVES * save S record dump
796 CONFIG_CMD_SCSI * SCSI Support
797 CONFIG_CMD_SDRAM * print SDRAM configuration information
798 (requires CONFIG_CMD_I2C)
799 CONFIG_CMD_SETGETDCR Support for DCR Register access
801 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
802 CONFIG_CMD_SHA1SUM print sha1 memory digest
803 (requires CONFIG_CMD_MEMORY)
804 CONFIG_CMD_SOURCE "source" command Support
805 CONFIG_CMD_SPI * SPI serial bus support
806 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
807 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
808 CONFIG_CMD_TIME * run command and report execution time
809 CONFIG_CMD_USB * USB support
810 CONFIG_CMD_CDP * Cisco Discover Protocol support
811 CONFIG_CMD_FSL * Microblaze FSL support
814 EXAMPLE: If you want all functions except of network
815 support you can write:
817 #include "config_cmd_all.h"
818 #undef CONFIG_CMD_NET
821 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
823 Note: Don't enable the "icache" and "dcache" commands
824 (configuration option CONFIG_CMD_CACHE) unless you know
825 what you (and your U-Boot users) are doing. Data
826 cache cannot be enabled on systems like the 8xx or
827 8260 (where accesses to the IMMR region must be
828 uncached), and it cannot be disabled on all other
829 systems where we (mis-) use the data cache to hold an
830 initial stack and some data.
833 XXX - this list needs to get updated!
837 If this variable is defined, U-Boot will use a device tree
838 to configure its devices, instead of relying on statically
839 compiled #defines in the board file. This option is
840 experimental and only available on a few boards. The device
841 tree is available in the global data as gd->fdt_blob.
843 U-Boot needs to get its device tree from somewhere. This can
844 be done using one of the two options below:
847 If this variable is defined, U-Boot will embed a device tree
848 binary in its image. This device tree file should be in the
849 board directory and called <soc>-<board>.dts. The binary file
850 is then picked up in board_init_f() and made available through
851 the global data structure as gd->blob.
854 If this variable is defined, U-Boot will build a device tree
855 binary. It will be called u-boot.dtb. Architecture-specific
856 code will locate it at run-time. Generally this works by:
858 cat u-boot.bin u-boot.dtb >image.bin
860 and in fact, U-Boot does this for you, creating a file called
861 u-boot-dtb.bin which is useful in the common case. You can
862 still use the individual files if you need something more
867 If this variable is defined, it enables watchdog
868 support for the SoC. There must be support in the SoC
869 specific code for a watchdog. For the 8xx and 8260
870 CPUs, the SIU Watchdog feature is enabled in the SYPCR
871 register. When supported for a specific SoC is
872 available, then no further board specific code should
876 When using a watchdog circuitry external to the used
877 SoC, then define this variable and provide board
878 specific code for the "hw_watchdog_reset" function.
881 CONFIG_VERSION_VARIABLE
882 If this variable is defined, an environment variable
883 named "ver" is created by U-Boot showing the U-Boot
884 version as printed by the "version" command.
885 This variable is readonly.
889 When CONFIG_CMD_DATE is selected, the type of the RTC
890 has to be selected, too. Define exactly one of the
893 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
894 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
895 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
896 CONFIG_RTC_MC146818 - use MC146818 RTC
897 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
898 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
899 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
900 CONFIG_RTC_DS164x - use Dallas DS164x RTC
901 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
902 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
903 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
904 CONFIG_SYS_RV3029_TCR - enable trickle charger on
907 Note that if the RTC uses I2C, then the I2C interface
908 must also be configured. See I2C Support, below.
911 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
912 CONFIG_PCA953X_INFO - enable pca953x info command
914 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
915 chip-ngpio pairs that tell the PCA953X driver the number of
916 pins supported by a particular chip.
918 Note that if the GPIO device uses I2C, then the I2C interface
919 must also be configured. See I2C Support, below.
923 When CONFIG_TIMESTAMP is selected, the timestamp
924 (date and time) of an image is printed by image
925 commands like bootm or iminfo. This option is
926 automatically enabled when you select CONFIG_CMD_DATE .
929 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
930 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
932 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
933 CONFIG_CMD_SCSI) you must configure support for at
934 least one partition type as well.
937 CONFIG_IDE_RESET_ROUTINE - this is defined in several
938 board configurations files but used nowhere!
940 CONFIG_IDE_RESET - is this is defined, IDE Reset will
941 be performed by calling the function
942 ide_set_reset(int reset)
943 which has to be defined in a board specific file
948 Set this to enable ATAPI support.
953 Set this to enable support for disks larger than 137GB
954 Also look at CONFIG_SYS_64BIT_LBA.
955 Whithout these , LBA48 support uses 32bit variables and will 'only'
956 support disks up to 2.1TB.
958 CONFIG_SYS_64BIT_LBA:
959 When enabled, makes the IDE subsystem use 64bit sector addresses.
963 At the moment only there is only support for the
964 SYM53C8XX SCSI controller; define
965 CONFIG_SCSI_SYM53C8XX to enable it.
967 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
968 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
969 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
970 maximum numbers of LUNs, SCSI ID's and target
972 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
974 - NETWORK Support (PCI):
976 Support for Intel 8254x/8257x gigabit chips.
979 Utility code for direct access to the SPI bus on Intel 8257x.
980 This does not do anything useful unless you set at least one
981 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
983 CONFIG_E1000_SPI_GENERIC
984 Allow generic access to the SPI bus on the Intel 8257x, for
985 example with the "sspi" command.
988 Management command for E1000 devices. When used on devices
989 with SPI support you can reprogram the EEPROM from U-Boot.
991 CONFIG_E1000_FALLBACK_MAC
992 default MAC for empty EEPROM after production.
995 Support for Intel 82557/82559/82559ER chips.
996 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
997 write routine for first time initialisation.
1000 Support for Digital 2114x chips.
1001 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1002 modem chip initialisation (KS8761/QS6611).
1005 Support for National dp83815 chips.
1008 Support for National dp8382[01] gigabit chips.
1010 - NETWORK Support (other):
1012 CONFIG_DRIVER_AT91EMAC
1013 Support for AT91RM9200 EMAC.
1016 Define this to use reduced MII inteface
1018 CONFIG_DRIVER_AT91EMAC_QUIET
1019 If this defined, the driver is quiet.
1020 The driver doen't show link status messages.
1022 CONFIG_CALXEDA_XGMAC
1023 Support for the Calxeda XGMAC device
1025 CONFIG_DRIVER_LAN91C96
1026 Support for SMSC's LAN91C96 chips.
1028 CONFIG_LAN91C96_BASE
1029 Define this to hold the physical address
1030 of the LAN91C96's I/O space
1032 CONFIG_LAN91C96_USE_32_BIT
1033 Define this to enable 32 bit addressing
1035 CONFIG_DRIVER_SMC91111
1036 Support for SMSC's LAN91C111 chip
1038 CONFIG_SMC91111_BASE
1039 Define this to hold the physical address
1040 of the device (I/O space)
1042 CONFIG_SMC_USE_32_BIT
1043 Define this if data bus is 32 bits
1045 CONFIG_SMC_USE_IOFUNCS
1046 Define this to use i/o functions instead of macros
1047 (some hardware wont work with macros)
1049 CONFIG_DRIVER_TI_EMAC
1050 Support for davinci emac
1052 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1053 Define this if you have more then 3 PHYs.
1056 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1058 CONFIG_FTGMAC100_EGIGA
1059 Define this to use GE link update with gigabit PHY.
1060 Define this if FTGMAC100 is connected to gigabit PHY.
1061 If your system has 10/100 PHY only, it might not occur
1062 wrong behavior. Because PHY usually return timeout or
1063 useless data when polling gigabit status and gigabit
1064 control registers. This behavior won't affect the
1065 correctnessof 10/100 link speed update.
1068 Support for SMSC's LAN911x and LAN921x chips
1071 Define this to hold the physical address
1072 of the device (I/O space)
1074 CONFIG_SMC911X_32_BIT
1075 Define this if data bus is 32 bits
1077 CONFIG_SMC911X_16_BIT
1078 Define this if data bus is 16 bits. If your processor
1079 automatically converts one 32 bit word to two 16 bit
1080 words you may also try CONFIG_SMC911X_32_BIT.
1083 Support for Renesas on-chip Ethernet controller
1085 CONFIG_SH_ETHER_USE_PORT
1086 Define the number of ports to be used
1088 CONFIG_SH_ETHER_PHY_ADDR
1089 Define the ETH PHY's address
1091 CONFIG_SH_ETHER_CACHE_WRITEBACK
1092 If this option is set, the driver enables cache flush.
1095 CONFIG_GENERIC_LPC_TPM
1096 Support for generic parallel port TPM devices. Only one device
1097 per system is supported at this time.
1099 CONFIG_TPM_TIS_BASE_ADDRESS
1100 Base address where the generic TPM device is mapped
1101 to. Contemporary x86 systems usually map it at
1105 At the moment only the UHCI host controller is
1106 supported (PIP405, MIP405, MPC5200); define
1107 CONFIG_USB_UHCI to enable it.
1108 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1109 and define CONFIG_USB_STORAGE to enable the USB
1112 Supported are USB Keyboards and USB Floppy drives
1114 MPC5200 USB requires additional defines:
1116 for 528 MHz Clock: 0x0001bbbb
1120 for differential drivers: 0x00001000
1121 for single ended drivers: 0x00005000
1122 for differential drivers on PSC3: 0x00000100
1123 for single ended drivers on PSC3: 0x00004100
1124 CONFIG_SYS_USB_EVENT_POLL
1125 May be defined to allow interrupt polling
1126 instead of using asynchronous interrupts
1129 Define the below if you wish to use the USB console.
1130 Once firmware is rebuilt from a serial console issue the
1131 command "setenv stdin usbtty; setenv stdout usbtty" and
1132 attach your USB cable. The Unix command "dmesg" should print
1133 it has found a new device. The environment variable usbtty
1134 can be set to gserial or cdc_acm to enable your device to
1135 appear to a USB host as a Linux gserial device or a
1136 Common Device Class Abstract Control Model serial device.
1137 If you select usbtty = gserial you should be able to enumerate
1139 # modprobe usbserial vendor=0xVendorID product=0xProductID
1140 else if using cdc_acm, simply setting the environment
1141 variable usbtty to be cdc_acm should suffice. The following
1142 might be defined in YourBoardName.h
1145 Define this to build a UDC device
1148 Define this to have a tty type of device available to
1149 talk to the UDC device
1152 Define this to enable the high speed support for usb
1153 device and usbtty. If this feature is enabled, a routine
1154 int is_usbd_high_speed(void)
1155 also needs to be defined by the driver to dynamically poll
1156 whether the enumeration has succeded at high speed or full
1159 CONFIG_SYS_CONSOLE_IS_IN_ENV
1160 Define this if you want stdin, stdout &/or stderr to
1164 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1165 Derive USB clock from external clock "blah"
1166 - CONFIG_SYS_USB_EXTC_CLK 0x02
1168 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1169 Derive USB clock from brgclk
1170 - CONFIG_SYS_USB_BRG_CLK 0x04
1172 If you have a USB-IF assigned VendorID then you may wish to
1173 define your own vendor specific values either in BoardName.h
1174 or directly in usbd_vendor_info.h. If you don't define
1175 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1176 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1177 should pretend to be a Linux device to it's target host.
1179 CONFIG_USBD_MANUFACTURER
1180 Define this string as the name of your company for
1181 - CONFIG_USBD_MANUFACTURER "my company"
1183 CONFIG_USBD_PRODUCT_NAME
1184 Define this string as the name of your product
1185 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1187 CONFIG_USBD_VENDORID
1188 Define this as your assigned Vendor ID from the USB
1189 Implementors Forum. This *must* be a genuine Vendor ID
1190 to avoid polluting the USB namespace.
1191 - CONFIG_USBD_VENDORID 0xFFFF
1193 CONFIG_USBD_PRODUCTID
1194 Define this as the unique Product ID
1196 - CONFIG_USBD_PRODUCTID 0xFFFF
1198 - ULPI Layer Support:
1199 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1200 the generic ULPI layer. The generic layer accesses the ULPI PHY
1201 via the platform viewport, so you need both the genric layer and
1202 the viewport enabled. Currently only Chipidea/ARC based
1203 viewport is supported.
1204 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1205 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1208 The MMC controller on the Intel PXA is supported. To
1209 enable this define CONFIG_MMC. The MMC can be
1210 accessed from the boot prompt by mapping the device
1211 to physical memory similar to flash. Command line is
1212 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1213 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1216 Support for Renesas on-chip MMCIF controller
1218 CONFIG_SH_MMCIF_ADDR
1219 Define the base address of MMCIF registers
1222 Define the clock frequency for MMCIF
1224 - Journaling Flash filesystem support:
1225 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1226 CONFIG_JFFS2_NAND_DEV
1227 Define these for a default partition on a NAND device
1229 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1230 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1231 Define these for a default partition on a NOR device
1233 CONFIG_SYS_JFFS_CUSTOM_PART
1234 Define this to create an own partition. You have to provide a
1235 function struct part_info* jffs2_part_info(int part_num)
1237 If you define only one JFFS2 partition you may also want to
1238 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1239 to disable the command chpart. This is the default when you
1240 have not defined a custom partition
1242 - FAT(File Allocation Table) filesystem write function support:
1244 Support for saving memory data as a file
1245 in FAT formatted partition
1250 Define this to enable standard (PC-Style) keyboard
1254 Standard PC keyboard driver with US (is default) and
1255 GERMAN key layout (switch via environment 'keymap=de') support.
1256 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1257 for cfb_console. Supports cursor blinking.
1262 Define this to enable video support (for output to
1265 CONFIG_VIDEO_CT69000
1267 Enable Chips & Technologies 69000 Video chip
1269 CONFIG_VIDEO_SMI_LYNXEM
1270 Enable Silicon Motion SMI 712/710/810 Video chip. The
1271 video output is selected via environment 'videoout'
1272 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1275 For the CT69000 and SMI_LYNXEM drivers, videomode is
1276 selected via environment 'videomode'. Two different ways
1278 - "videomode=num" 'num' is a standard LiLo mode numbers.
1279 Following standard modes are supported (* is default):
1281 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1282 -------------+---------------------------------------------
1283 8 bits | 0x301* 0x303 0x305 0x161 0x307
1284 15 bits | 0x310 0x313 0x316 0x162 0x319
1285 16 bits | 0x311 0x314 0x317 0x163 0x31A
1286 24 bits | 0x312 0x315 0x318 ? 0x31B
1287 -------------+---------------------------------------------
1288 (i.e. setenv videomode 317; saveenv; reset;)
1290 - "videomode=bootargs" all the video parameters are parsed
1291 from the bootargs. (See drivers/video/videomodes.c)
1294 CONFIG_VIDEO_SED13806
1295 Enable Epson SED13806 driver. This driver supports 8bpp
1296 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1297 or CONFIG_VIDEO_SED13806_16BPP
1300 Enable the Freescale DIU video driver. Reference boards for
1301 SOCs that have a DIU should define this macro to enable DIU
1302 support, and should also define these other macros:
1308 CONFIG_VIDEO_SW_CURSOR
1309 CONFIG_VGA_AS_SINGLE_DEVICE
1311 CONFIG_VIDEO_BMP_LOGO
1313 The DIU driver will look for the 'video-mode' environment
1314 variable, and if defined, enable the DIU as a console during
1315 boot. See the documentation file README.video for a
1316 description of this variable.
1321 Define this to enable a custom keyboard support.
1322 This simply calls drv_keyboard_init() which must be
1323 defined in your board-specific files.
1324 The only board using this so far is RBC823.
1326 - LCD Support: CONFIG_LCD
1328 Define this to enable LCD support (for output to LCD
1329 display); also select one of the supported displays
1330 by defining one of these:
1334 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1336 CONFIG_NEC_NL6448AC33:
1338 NEC NL6448AC33-18. Active, color, single scan.
1340 CONFIG_NEC_NL6448BC20
1342 NEC NL6448BC20-08. 6.5", 640x480.
1343 Active, color, single scan.
1345 CONFIG_NEC_NL6448BC33_54
1347 NEC NL6448BC33-54. 10.4", 640x480.
1348 Active, color, single scan.
1352 Sharp 320x240. Active, color, single scan.
1353 It isn't 16x9, and I am not sure what it is.
1355 CONFIG_SHARP_LQ64D341
1357 Sharp LQ64D341 display, 640x480.
1358 Active, color, single scan.
1362 HLD1045 display, 640x480.
1363 Active, color, single scan.
1367 Optrex CBL50840-2 NF-FW 99 22 M5
1369 Hitachi LMG6912RPFC-00T
1373 320x240. Black & white.
1375 Normally display is black on white background; define
1376 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1378 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1380 If this option is set, the environment is checked for
1381 a variable "splashimage". If found, the usual display
1382 of logo, copyright and system information on the LCD
1383 is suppressed and the BMP image at the address
1384 specified in "splashimage" is loaded instead. The
1385 console is redirected to the "nulldev", too. This
1386 allows for a "silent" boot where a splash screen is
1387 loaded very quickly after power-on.
1389 CONFIG_SPLASH_SCREEN_ALIGN
1391 If this option is set the splash image can be freely positioned
1392 on the screen. Environment variable "splashpos" specifies the
1393 position as "x,y". If a positive number is given it is used as
1394 number of pixel from left/top. If a negative number is given it
1395 is used as number of pixel from right/bottom. You can also
1396 specify 'm' for centering the image.
1399 setenv splashpos m,m
1400 => image at center of screen
1402 setenv splashpos 30,20
1403 => image at x = 30 and y = 20
1405 setenv splashpos -10,m
1406 => vertically centered image
1407 at x = dspWidth - bmpWidth - 9
1409 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1411 If this option is set, additionally to standard BMP
1412 images, gzipped BMP images can be displayed via the
1413 splashscreen support or the bmp command.
1415 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1417 If this option is set, 8-bit RLE compressed BMP images
1418 can be displayed via the splashscreen support or the
1421 - Compression support:
1424 If this option is set, support for bzip2 compressed
1425 images is included. If not, only uncompressed and gzip
1426 compressed images are supported.
1428 NOTE: the bzip2 algorithm requires a lot of RAM, so
1429 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1434 If this option is set, support for lzma compressed
1437 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1438 requires an amount of dynamic memory that is given by the
1441 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1443 Where lc and lp stand for, respectively, Literal context bits
1444 and Literal pos bits.
1446 This value is upper-bounded by 14MB in the worst case. Anyway,
1447 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1448 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1449 a very small buffer.
1451 Use the lzmainfo tool to determinate the lc and lp values and
1452 then calculate the amount of needed dynamic memory (ensuring
1453 the appropriate CONFIG_SYS_MALLOC_LEN value).
1458 The address of PHY on MII bus.
1460 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1462 The clock frequency of the MII bus
1466 If this option is set, support for speed/duplex
1467 detection of gigabit PHY is included.
1469 CONFIG_PHY_RESET_DELAY
1471 Some PHY like Intel LXT971A need extra delay after
1472 reset before any MII register access is possible.
1473 For such PHY, set this option to the usec delay
1474 required. (minimum 300usec for LXT971A)
1476 CONFIG_PHY_CMD_DELAY (ppc4xx)
1478 Some PHY like Intel LXT971A need extra delay after
1479 command issued before MII status register can be read
1489 Define a default value for Ethernet address to use
1490 for the respective Ethernet interface, in case this
1491 is not determined automatically.
1496 Define a default value for the IP address to use for
1497 the default Ethernet interface, in case this is not
1498 determined through e.g. bootp.
1499 (Environment variable "ipaddr")
1501 - Server IP address:
1504 Defines a default value for the IP address of a TFTP
1505 server to contact when using the "tftboot" command.
1506 (Environment variable "serverip")
1508 CONFIG_KEEP_SERVERADDR
1510 Keeps the server's MAC address, in the env 'serveraddr'
1511 for passing to bootargs (like Linux's netconsole option)
1513 - Gateway IP address:
1516 Defines a default value for the IP address of the
1517 default router where packets to other networks are
1519 (Environment variable "gatewayip")
1524 Defines a default value for the subnet mask (or
1525 routing prefix) which is used to determine if an IP
1526 address belongs to the local subnet or needs to be
1527 forwarded through a router.
1528 (Environment variable "netmask")
1530 - Multicast TFTP Mode:
1533 Defines whether you want to support multicast TFTP as per
1534 rfc-2090; for example to work with atftp. Lets lots of targets
1535 tftp down the same boot image concurrently. Note: the Ethernet
1536 driver in use must provide a function: mcast() to join/leave a
1539 - BOOTP Recovery Mode:
1540 CONFIG_BOOTP_RANDOM_DELAY
1542 If you have many targets in a network that try to
1543 boot using BOOTP, you may want to avoid that all
1544 systems send out BOOTP requests at precisely the same
1545 moment (which would happen for instance at recovery
1546 from a power failure, when all systems will try to
1547 boot, thus flooding the BOOTP server. Defining
1548 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1549 inserted before sending out BOOTP requests. The
1550 following delays are inserted then:
1552 1st BOOTP request: delay 0 ... 1 sec
1553 2nd BOOTP request: delay 0 ... 2 sec
1554 3rd BOOTP request: delay 0 ... 4 sec
1556 BOOTP requests: delay 0 ... 8 sec
1558 - DHCP Advanced Options:
1559 You can fine tune the DHCP functionality by defining
1560 CONFIG_BOOTP_* symbols:
1562 CONFIG_BOOTP_SUBNETMASK
1563 CONFIG_BOOTP_GATEWAY
1564 CONFIG_BOOTP_HOSTNAME
1565 CONFIG_BOOTP_NISDOMAIN
1566 CONFIG_BOOTP_BOOTPATH
1567 CONFIG_BOOTP_BOOTFILESIZE
1570 CONFIG_BOOTP_SEND_HOSTNAME
1571 CONFIG_BOOTP_NTPSERVER
1572 CONFIG_BOOTP_TIMEOFFSET
1573 CONFIG_BOOTP_VENDOREX
1575 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1576 environment variable, not the BOOTP server.
1578 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1579 serverip from a DHCP server, it is possible that more
1580 than one DNS serverip is offered to the client.
1581 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1582 serverip will be stored in the additional environment
1583 variable "dnsip2". The first DNS serverip is always
1584 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1587 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1588 to do a dynamic update of a DNS server. To do this, they
1589 need the hostname of the DHCP requester.
1590 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1591 of the "hostname" environment variable is passed as
1592 option 12 to the DHCP server.
1594 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1596 A 32bit value in microseconds for a delay between
1597 receiving a "DHCP Offer" and sending the "DHCP Request".
1598 This fixes a problem with certain DHCP servers that don't
1599 respond 100% of the time to a "DHCP request". E.g. On an
1600 AT91RM9200 processor running at 180MHz, this delay needed
1601 to be *at least* 15,000 usec before a Windows Server 2003
1602 DHCP server would reply 100% of the time. I recommend at
1603 least 50,000 usec to be safe. The alternative is to hope
1604 that one of the retries will be successful but note that
1605 the DHCP timeout and retry process takes a longer than
1609 CONFIG_CDP_DEVICE_ID
1611 The device id used in CDP trigger frames.
1613 CONFIG_CDP_DEVICE_ID_PREFIX
1615 A two character string which is prefixed to the MAC address
1620 A printf format string which contains the ascii name of
1621 the port. Normally is set to "eth%d" which sets
1622 eth0 for the first Ethernet, eth1 for the second etc.
1624 CONFIG_CDP_CAPABILITIES
1626 A 32bit integer which indicates the device capabilities;
1627 0x00000010 for a normal host which does not forwards.
1631 An ascii string containing the version of the software.
1635 An ascii string containing the name of the platform.
1639 A 32bit integer sent on the trigger.
1641 CONFIG_CDP_POWER_CONSUMPTION
1643 A 16bit integer containing the power consumption of the
1644 device in .1 of milliwatts.
1646 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1648 A byte containing the id of the VLAN.
1650 - Status LED: CONFIG_STATUS_LED
1652 Several configurations allow to display the current
1653 status using a LED. For instance, the LED will blink
1654 fast while running U-Boot code, stop blinking as
1655 soon as a reply to a BOOTP request was received, and
1656 start blinking slow once the Linux kernel is running
1657 (supported by a status LED driver in the Linux
1658 kernel). Defining CONFIG_STATUS_LED enables this
1661 - CAN Support: CONFIG_CAN_DRIVER
1663 Defining CONFIG_CAN_DRIVER enables CAN driver support
1664 on those systems that support this (optional)
1665 feature, like the TQM8xxL modules.
1667 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1669 These enable I2C serial bus commands. Defining either of
1670 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1671 include the appropriate I2C driver for the selected CPU.
1673 This will allow you to use i2c commands at the u-boot
1674 command line (as long as you set CONFIG_CMD_I2C in
1675 CONFIG_COMMANDS) and communicate with i2c based realtime
1676 clock chips. See common/cmd_i2c.c for a description of the
1677 command line interface.
1679 CONFIG_HARD_I2C selects a hardware I2C controller.
1681 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1682 bit-banging) driver instead of CPM or similar hardware
1685 There are several other quantities that must also be
1686 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1688 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1689 to be the frequency (in Hz) at which you wish your i2c bus
1690 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1691 the CPU's i2c node address).
1693 Now, the u-boot i2c code for the mpc8xx
1694 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1695 and so its address should therefore be cleared to 0 (See,
1696 eg, MPC823e User's Manual p.16-473). So, set
1697 CONFIG_SYS_I2C_SLAVE to 0.
1699 CONFIG_SYS_I2C_INIT_MPC5XXX
1701 When a board is reset during an i2c bus transfer
1702 chips might think that the current transfer is still
1703 in progress. Reset the slave devices by sending start
1704 commands until the slave device responds.
1706 That's all that's required for CONFIG_HARD_I2C.
1708 If you use the software i2c interface (CONFIG_SOFT_I2C)
1709 then the following macros need to be defined (examples are
1710 from include/configs/lwmon.h):
1714 (Optional). Any commands necessary to enable the I2C
1715 controller or configure ports.
1717 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1721 (Only for MPC8260 CPU). The I/O port to use (the code
1722 assumes both bits are on the same port). Valid values
1723 are 0..3 for ports A..D.
1727 The code necessary to make the I2C data line active
1728 (driven). If the data line is open collector, this
1731 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1735 The code necessary to make the I2C data line tri-stated
1736 (inactive). If the data line is open collector, this
1739 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1743 Code that returns TRUE if the I2C data line is high,
1746 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1750 If <bit> is TRUE, sets the I2C data line high. If it
1751 is FALSE, it clears it (low).
1753 eg: #define I2C_SDA(bit) \
1754 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1755 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1759 If <bit> is TRUE, sets the I2C clock line high. If it
1760 is FALSE, it clears it (low).
1762 eg: #define I2C_SCL(bit) \
1763 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1764 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1768 This delay is invoked four times per clock cycle so this
1769 controls the rate of data transfer. The data rate thus
1770 is 1 / (I2C_DELAY * 4). Often defined to be something
1773 #define I2C_DELAY udelay(2)
1775 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1777 If your arch supports the generic GPIO framework (asm/gpio.h),
1778 then you may alternatively define the two GPIOs that are to be
1779 used as SCL / SDA. Any of the previous I2C_xxx macros will
1780 have GPIO-based defaults assigned to them as appropriate.
1782 You should define these to the GPIO value as given directly to
1783 the generic GPIO functions.
1785 CONFIG_SYS_I2C_INIT_BOARD
1787 When a board is reset during an i2c bus transfer
1788 chips might think that the current transfer is still
1789 in progress. On some boards it is possible to access
1790 the i2c SCLK line directly, either by using the
1791 processor pin as a GPIO or by having a second pin
1792 connected to the bus. If this option is defined a
1793 custom i2c_init_board() routine in boards/xxx/board.c
1794 is run early in the boot sequence.
1796 CONFIG_SYS_I2C_BOARD_LATE_INIT
1798 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1799 defined a custom i2c_board_late_init() routine in
1800 boards/xxx/board.c is run AFTER the operations in i2c_init()
1801 is completed. This callpoint can be used to unreset i2c bus
1802 using CPU i2c controller register accesses for CPUs whose i2c
1803 controller provide such a method. It is called at the end of
1804 i2c_init() to allow i2c_init operations to setup the i2c bus
1805 controller on the CPU (e.g. setting bus speed & slave address).
1807 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1809 This option enables configuration of bi_iic_fast[] flags
1810 in u-boot bd_info structure based on u-boot environment
1811 variable "i2cfast". (see also i2cfast)
1813 CONFIG_I2C_MULTI_BUS
1815 This option allows the use of multiple I2C buses, each of which
1816 must have a controller. At any point in time, only one bus is
1817 active. To switch to a different bus, use the 'i2c dev' command.
1818 Note that bus numbering is zero-based.
1820 CONFIG_SYS_I2C_NOPROBES
1822 This option specifies a list of I2C devices that will be skipped
1823 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1824 is set, specify a list of bus-device pairs. Otherwise, specify
1825 a 1D array of device addresses
1828 #undef CONFIG_I2C_MULTI_BUS
1829 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1831 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1833 #define CONFIG_I2C_MULTI_BUS
1834 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1836 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1838 CONFIG_SYS_SPD_BUS_NUM
1840 If defined, then this indicates the I2C bus number for DDR SPD.
1841 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1843 CONFIG_SYS_RTC_BUS_NUM
1845 If defined, then this indicates the I2C bus number for the RTC.
1846 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1848 CONFIG_SYS_DTT_BUS_NUM
1850 If defined, then this indicates the I2C bus number for the DTT.
1851 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1853 CONFIG_SYS_I2C_DTT_ADDR:
1855 If defined, specifies the I2C address of the DTT device.
1856 If not defined, then U-Boot uses predefined value for
1857 specified DTT device.
1861 Define this option if you want to use Freescale's I2C driver in
1862 drivers/i2c/fsl_i2c.c.
1866 Define this option if you have I2C devices reached over 1 .. n
1867 I2C Muxes like the pca9544a. This option addes a new I2C
1868 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1869 new I2C Bus to the existing I2C Busses. If you select the
1870 new Bus with "i2c dev", u-bbot sends first the commandos for
1871 the muxes to activate this new "bus".
1873 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1877 Adding a new I2C Bus reached over 2 pca9544a muxes
1878 The First mux with address 70 and channel 6
1879 The Second mux with address 71 and channel 4
1881 => i2c bus pca9544a:70:6:pca9544a:71:4
1883 Use the "i2c bus" command without parameter, to get a list
1884 of I2C Busses with muxes:
1887 Busses reached over muxes:
1889 reached over Mux(es):
1892 reached over Mux(es):
1897 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1898 u-boot first sends the command to the mux@70 to enable
1899 channel 6, and then the command to the mux@71 to enable
1902 After that, you can use the "normal" i2c commands as
1903 usual to communicate with your I2C devices behind
1906 This option is actually implemented for the bitbanging
1907 algorithm in common/soft_i2c.c and for the Hardware I2C
1908 Bus on the MPC8260. But it should be not so difficult
1909 to add this option to other architectures.
1911 CONFIG_SOFT_I2C_READ_REPEATED_START
1913 defining this will force the i2c_read() function in
1914 the soft_i2c driver to perform an I2C repeated start
1915 between writing the address pointer and reading the
1916 data. If this define is omitted the default behaviour
1917 of doing a stop-start sequence will be used. Most I2C
1918 devices can use either method, but some require one or
1921 - SPI Support: CONFIG_SPI
1923 Enables SPI driver (so far only tested with
1924 SPI EEPROM, also an instance works with Crystal A/D and
1925 D/As on the SACSng board)
1929 Enables the driver for SPI controller on SuperH. Currently
1930 only SH7757 is supported.
1934 Enables extended (16-bit) SPI EEPROM addressing.
1935 (symmetrical to CONFIG_I2C_X)
1939 Enables a software (bit-bang) SPI driver rather than
1940 using hardware support. This is a general purpose
1941 driver that only requires three general I/O port pins
1942 (two outputs, one input) to function. If this is
1943 defined, the board configuration must define several
1944 SPI configuration items (port pins to use, etc). For
1945 an example, see include/configs/sacsng.h.
1949 Enables a hardware SPI driver for general-purpose reads
1950 and writes. As with CONFIG_SOFT_SPI, the board configuration
1951 must define a list of chip-select function pointers.
1952 Currently supported on some MPC8xxx processors. For an
1953 example, see include/configs/mpc8349emds.h.
1957 Enables the driver for the SPI controllers on i.MX and MXC
1958 SoCs. Currently i.MX31/35/51 are supported.
1960 - FPGA Support: CONFIG_FPGA
1962 Enables FPGA subsystem.
1964 CONFIG_FPGA_<vendor>
1966 Enables support for specific chip vendors.
1969 CONFIG_FPGA_<family>
1971 Enables support for FPGA family.
1972 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1976 Specify the number of FPGA devices to support.
1978 CONFIG_SYS_FPGA_PROG_FEEDBACK
1980 Enable printing of hash marks during FPGA configuration.
1982 CONFIG_SYS_FPGA_CHECK_BUSY
1984 Enable checks on FPGA configuration interface busy
1985 status by the configuration function. This option
1986 will require a board or device specific function to
1991 If defined, a function that provides delays in the FPGA
1992 configuration driver.
1994 CONFIG_SYS_FPGA_CHECK_CTRLC
1995 Allow Control-C to interrupt FPGA configuration
1997 CONFIG_SYS_FPGA_CHECK_ERROR
1999 Check for configuration errors during FPGA bitfile
2000 loading. For example, abort during Virtex II
2001 configuration if the INIT_B line goes low (which
2002 indicated a CRC error).
2004 CONFIG_SYS_FPGA_WAIT_INIT
2006 Maximum time to wait for the INIT_B line to deassert
2007 after PROB_B has been deasserted during a Virtex II
2008 FPGA configuration sequence. The default time is 500
2011 CONFIG_SYS_FPGA_WAIT_BUSY
2013 Maximum time to wait for BUSY to deassert during
2014 Virtex II FPGA configuration. The default is 5 ms.
2016 CONFIG_SYS_FPGA_WAIT_CONFIG
2018 Time to wait after FPGA configuration. The default is
2021 - Configuration Management:
2024 If defined, this string will be added to the U-Boot
2025 version information (U_BOOT_VERSION)
2027 - Vendor Parameter Protection:
2029 U-Boot considers the values of the environment
2030 variables "serial#" (Board Serial Number) and
2031 "ethaddr" (Ethernet Address) to be parameters that
2032 are set once by the board vendor / manufacturer, and
2033 protects these variables from casual modification by
2034 the user. Once set, these variables are read-only,
2035 and write or delete attempts are rejected. You can
2036 change this behaviour:
2038 If CONFIG_ENV_OVERWRITE is #defined in your config
2039 file, the write protection for vendor parameters is
2040 completely disabled. Anybody can change or delete
2043 Alternatively, if you #define _both_ CONFIG_ETHADDR
2044 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2045 Ethernet address is installed in the environment,
2046 which can be changed exactly ONCE by the user. [The
2047 serial# is unaffected by this, i. e. it remains
2053 Define this variable to enable the reservation of
2054 "protected RAM", i. e. RAM which is not overwritten
2055 by U-Boot. Define CONFIG_PRAM to hold the number of
2056 kB you want to reserve for pRAM. You can overwrite
2057 this default value by defining an environment
2058 variable "pram" to the number of kB you want to
2059 reserve. Note that the board info structure will
2060 still show the full amount of RAM. If pRAM is
2061 reserved, a new environment variable "mem" will
2062 automatically be defined to hold the amount of
2063 remaining RAM in a form that can be passed as boot
2064 argument to Linux, for instance like that:
2066 setenv bootargs ... mem=\${mem}
2069 This way you can tell Linux not to use this memory,
2070 either, which results in a memory region that will
2071 not be affected by reboots.
2073 *WARNING* If your board configuration uses automatic
2074 detection of the RAM size, you must make sure that
2075 this memory test is non-destructive. So far, the
2076 following board configurations are known to be
2079 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2080 HERMES, IP860, RPXlite, LWMON, LANTEC,
2086 Define this variable to stop the system in case of a
2087 fatal error, so that you have to reset it manually.
2088 This is probably NOT a good idea for an embedded
2089 system where you want the system to reboot
2090 automatically as fast as possible, but it may be
2091 useful during development since you can try to debug
2092 the conditions that lead to the situation.
2094 CONFIG_NET_RETRY_COUNT
2096 This variable defines the number of retries for
2097 network operations like ARP, RARP, TFTP, or BOOTP
2098 before giving up the operation. If not defined, a
2099 default value of 5 is used.
2103 Timeout waiting for an ARP reply in milliseconds.
2105 - Command Interpreter:
2106 CONFIG_AUTO_COMPLETE
2108 Enable auto completion of commands using TAB.
2110 Note that this feature has NOT been implemented yet
2111 for the "hush" shell.
2114 CONFIG_SYS_HUSH_PARSER
2116 Define this variable to enable the "hush" shell (from
2117 Busybox) as command line interpreter, thus enabling
2118 powerful command line syntax like
2119 if...then...else...fi conditionals or `&&' and '||'
2120 constructs ("shell scripts").
2122 If undefined, you get the old, much simpler behaviour
2123 with a somewhat smaller memory footprint.
2126 CONFIG_SYS_PROMPT_HUSH_PS2
2128 This defines the secondary prompt string, which is
2129 printed when the command interpreter needs more input
2130 to complete a command. Usually "> ".
2134 In the current implementation, the local variables
2135 space and global environment variables space are
2136 separated. Local variables are those you define by
2137 simply typing `name=value'. To access a local
2138 variable later on, you have write `$name' or
2139 `${name}'; to execute the contents of a variable
2140 directly type `$name' at the command prompt.
2142 Global environment variables are those you use
2143 setenv/printenv to work with. To run a command stored
2144 in such a variable, you need to use the run command,
2145 and you must not use the '$' sign to access them.
2147 To store commands and special characters in a
2148 variable, please use double quotation marks
2149 surrounding the whole text of the variable, instead
2150 of the backslashes before semicolons and special
2153 - Commandline Editing and History:
2154 CONFIG_CMDLINE_EDITING
2156 Enable editing and History functions for interactive
2157 commandline input operations
2159 - Default Environment:
2160 CONFIG_EXTRA_ENV_SETTINGS
2162 Define this to contain any number of null terminated
2163 strings (variable = value pairs) that will be part of
2164 the default environment compiled into the boot image.
2166 For example, place something like this in your
2167 board's config file:
2169 #define CONFIG_EXTRA_ENV_SETTINGS \
2173 Warning: This method is based on knowledge about the
2174 internal format how the environment is stored by the
2175 U-Boot code. This is NOT an official, exported
2176 interface! Although it is unlikely that this format
2177 will change soon, there is no guarantee either.
2178 You better know what you are doing here.
2180 Note: overly (ab)use of the default environment is
2181 discouraged. Make sure to check other ways to preset
2182 the environment like the "source" command or the
2185 - DataFlash Support:
2186 CONFIG_HAS_DATAFLASH
2188 Defining this option enables DataFlash features and
2189 allows to read/write in Dataflash via the standard
2192 - Serial Flash support
2195 Defining this option enables SPI flash commands
2196 'sf probe/read/write/erase/update'.
2198 Usage requires an initial 'probe' to define the serial
2199 flash parameters, followed by read/write/erase/update
2202 The following defaults may be provided by the platform
2203 to handle the common case when only a single serial
2204 flash is present on the system.
2206 CONFIG_SF_DEFAULT_BUS Bus identifier
2207 CONFIG_SF_DEFAULT_CS Chip-select
2208 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2209 CONFIG_SF_DEFAULT_SPEED in Hz
2211 - SystemACE Support:
2214 Adding this option adds support for Xilinx SystemACE
2215 chips attached via some sort of local bus. The address
2216 of the chip must also be defined in the
2217 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2219 #define CONFIG_SYSTEMACE
2220 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2222 When SystemACE support is added, the "ace" device type
2223 becomes available to the fat commands, i.e. fatls.
2225 - TFTP Fixed UDP Port:
2228 If this is defined, the environment variable tftpsrcp
2229 is used to supply the TFTP UDP source port value.
2230 If tftpsrcp isn't defined, the normal pseudo-random port
2231 number generator is used.
2233 Also, the environment variable tftpdstp is used to supply
2234 the TFTP UDP destination port value. If tftpdstp isn't
2235 defined, the normal port 69 is used.
2237 The purpose for tftpsrcp is to allow a TFTP server to
2238 blindly start the TFTP transfer using the pre-configured
2239 target IP address and UDP port. This has the effect of
2240 "punching through" the (Windows XP) firewall, allowing
2241 the remainder of the TFTP transfer to proceed normally.
2242 A better solution is to properly configure the firewall,
2243 but sometimes that is not allowed.
2245 - Show boot progress:
2246 CONFIG_SHOW_BOOT_PROGRESS
2248 Defining this option allows to add some board-
2249 specific code (calling a user-provided function
2250 "show_boot_progress(int)") that enables you to show
2251 the system's boot progress on some display (for
2252 example, some LED's) on your board. At the moment,
2253 the following checkpoints are implemented:
2255 - Detailed boot stage timing
2257 Define this option to get detailed timing of each stage
2258 of the boot process.
2260 CONFIG_BOOTSTAGE_USER_COUNT
2261 This is the number of available user bootstage records.
2262 Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
2263 a new ID will be allocated from this stash. If you exceed
2264 the limit, recording will stop.
2266 CONFIG_BOOTSTAGE_REPORT
2267 Define this to print a report before boot, similar to this:
2269 Timer summary in microseconds:
2272 3,575,678 3,575,678 board_init_f start
2273 3,575,695 17 arch_cpu_init A9
2274 3,575,777 82 arch_cpu_init done
2275 3,659,598 83,821 board_init_r start
2276 3,910,375 250,777 main_loop
2277 29,916,167 26,005,792 bootm_start
2278 30,361,327 445,160 start_kernel
2280 Legacy uImage format:
2283 1 common/cmd_bootm.c before attempting to boot an image
2284 -1 common/cmd_bootm.c Image header has bad magic number
2285 2 common/cmd_bootm.c Image header has correct magic number
2286 -2 common/cmd_bootm.c Image header has bad checksum
2287 3 common/cmd_bootm.c Image header has correct checksum
2288 -3 common/cmd_bootm.c Image data has bad checksum
2289 4 common/cmd_bootm.c Image data has correct checksum
2290 -4 common/cmd_bootm.c Image is for unsupported architecture
2291 5 common/cmd_bootm.c Architecture check OK
2292 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2293 6 common/cmd_bootm.c Image Type check OK
2294 -6 common/cmd_bootm.c gunzip uncompression error
2295 -7 common/cmd_bootm.c Unimplemented compression type
2296 7 common/cmd_bootm.c Uncompression OK
2297 8 common/cmd_bootm.c No uncompress/copy overwrite error
2298 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2300 9 common/image.c Start initial ramdisk verification
2301 -10 common/image.c Ramdisk header has bad magic number
2302 -11 common/image.c Ramdisk header has bad checksum
2303 10 common/image.c Ramdisk header is OK
2304 -12 common/image.c Ramdisk data has bad checksum
2305 11 common/image.c Ramdisk data has correct checksum
2306 12 common/image.c Ramdisk verification complete, start loading
2307 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2308 13 common/image.c Start multifile image verification
2309 14 common/image.c No initial ramdisk, no multifile, continue.
2311 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2313 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2314 -31 post/post.c POST test failed, detected by post_output_backlog()
2315 -32 post/post.c POST test failed, detected by post_run_single()
2317 34 common/cmd_doc.c before loading a Image from a DOC device
2318 -35 common/cmd_doc.c Bad usage of "doc" command
2319 35 common/cmd_doc.c correct usage of "doc" command
2320 -36 common/cmd_doc.c No boot device
2321 36 common/cmd_doc.c correct boot device
2322 -37 common/cmd_doc.c Unknown Chip ID on boot device
2323 37 common/cmd_doc.c correct chip ID found, device available
2324 -38 common/cmd_doc.c Read Error on boot device
2325 38 common/cmd_doc.c reading Image header from DOC device OK
2326 -39 common/cmd_doc.c Image header has bad magic number
2327 39 common/cmd_doc.c Image header has correct magic number
2328 -40 common/cmd_doc.c Error reading Image from DOC device
2329 40 common/cmd_doc.c Image header has correct magic number
2330 41 common/cmd_ide.c before loading a Image from a IDE device
2331 -42 common/cmd_ide.c Bad usage of "ide" command
2332 42 common/cmd_ide.c correct usage of "ide" command
2333 -43 common/cmd_ide.c No boot device
2334 43 common/cmd_ide.c boot device found
2335 -44 common/cmd_ide.c Device not available
2336 44 common/cmd_ide.c Device available
2337 -45 common/cmd_ide.c wrong partition selected
2338 45 common/cmd_ide.c partition selected
2339 -46 common/cmd_ide.c Unknown partition table
2340 46 common/cmd_ide.c valid partition table found
2341 -47 common/cmd_ide.c Invalid partition type
2342 47 common/cmd_ide.c correct partition type
2343 -48 common/cmd_ide.c Error reading Image Header on boot device
2344 48 common/cmd_ide.c reading Image Header from IDE device OK
2345 -49 common/cmd_ide.c Image header has bad magic number
2346 49 common/cmd_ide.c Image header has correct magic number
2347 -50 common/cmd_ide.c Image header has bad checksum
2348 50 common/cmd_ide.c Image header has correct checksum
2349 -51 common/cmd_ide.c Error reading Image from IDE device
2350 51 common/cmd_ide.c reading Image from IDE device OK
2351 52 common/cmd_nand.c before loading a Image from a NAND device
2352 -53 common/cmd_nand.c Bad usage of "nand" command
2353 53 common/cmd_nand.c correct usage of "nand" command
2354 -54 common/cmd_nand.c No boot device
2355 54 common/cmd_nand.c boot device found
2356 -55 common/cmd_nand.c Unknown Chip ID on boot device
2357 55 common/cmd_nand.c correct chip ID found, device available
2358 -56 common/cmd_nand.c Error reading Image Header on boot device
2359 56 common/cmd_nand.c reading Image Header from NAND device OK
2360 -57 common/cmd_nand.c Image header has bad magic number
2361 57 common/cmd_nand.c Image header has correct magic number
2362 -58 common/cmd_nand.c Error reading Image from NAND device
2363 58 common/cmd_nand.c reading Image from NAND device OK
2365 -60 common/env_common.c Environment has a bad CRC, using default
2367 64 net/eth.c starting with Ethernet configuration.
2368 -64 net/eth.c no Ethernet found.
2369 65 net/eth.c Ethernet found.
2371 -80 common/cmd_net.c usage wrong
2372 80 common/cmd_net.c before calling NetLoop()
2373 -81 common/cmd_net.c some error in NetLoop() occurred
2374 81 common/cmd_net.c NetLoop() back without error
2375 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2376 82 common/cmd_net.c trying automatic boot
2377 83 common/cmd_net.c running "source" command
2378 -83 common/cmd_net.c some error in automatic boot or "source" command
2379 84 common/cmd_net.c end without errors
2384 100 common/cmd_bootm.c Kernel FIT Image has correct format
2385 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2386 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2387 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2388 102 common/cmd_bootm.c Kernel unit name specified
2389 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2390 103 common/cmd_bootm.c Found configuration node
2391 104 common/cmd_bootm.c Got kernel subimage node offset
2392 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2393 105 common/cmd_bootm.c Kernel subimage hash verification OK
2394 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2395 106 common/cmd_bootm.c Architecture check OK
2396 -106 common/cmd_bootm.c Kernel subimage has wrong type
2397 107 common/cmd_bootm.c Kernel subimage type OK
2398 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2399 108 common/cmd_bootm.c Got kernel subimage data/size
2400 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2401 -109 common/cmd_bootm.c Can't get kernel subimage type
2402 -110 common/cmd_bootm.c Can't get kernel subimage comp
2403 -111 common/cmd_bootm.c Can't get kernel subimage os
2404 -112 common/cmd_bootm.c Can't get kernel subimage load address
2405 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2407 120 common/image.c Start initial ramdisk verification
2408 -120 common/image.c Ramdisk FIT image has incorrect format
2409 121 common/image.c Ramdisk FIT image has correct format
2410 122 common/image.c No ramdisk subimage unit name, using configuration
2411 -122 common/image.c Can't get configuration for ramdisk subimage
2412 123 common/image.c Ramdisk unit name specified
2413 -124 common/image.c Can't get ramdisk subimage node offset
2414 125 common/image.c Got ramdisk subimage node offset
2415 -125 common/image.c Ramdisk subimage hash verification failed
2416 126 common/image.c Ramdisk subimage hash verification OK
2417 -126 common/image.c Ramdisk subimage for unsupported architecture
2418 127 common/image.c Architecture check OK
2419 -127 common/image.c Can't get ramdisk subimage data/size
2420 128 common/image.c Got ramdisk subimage data/size
2421 129 common/image.c Can't get ramdisk load address
2422 -129 common/image.c Got ramdisk load address
2424 -130 common/cmd_doc.c Incorrect FIT image format
2425 131 common/cmd_doc.c FIT image format OK
2427 -140 common/cmd_ide.c Incorrect FIT image format
2428 141 common/cmd_ide.c FIT image format OK
2430 -150 common/cmd_nand.c Incorrect FIT image format
2431 151 common/cmd_nand.c FIT image format OK
2433 - Standalone program support:
2434 CONFIG_STANDALONE_LOAD_ADDR
2436 This option defines a board specific value for the
2437 address where standalone program gets loaded, thus
2438 overwriting the architecture dependent default
2441 - Frame Buffer Address:
2444 Define CONFIG_FB_ADDR if you want to use specific
2445 address for frame buffer.
2446 Then system will reserve the frame buffer address to
2447 defined address instead of lcd_setmem (this function
2448 grabs the memory for frame buffer by panel's size).
2450 Please see board_init_f function.
2452 - Automatic software updates via TFTP server
2454 CONFIG_UPDATE_TFTP_CNT_MAX
2455 CONFIG_UPDATE_TFTP_MSEC_MAX
2457 These options enable and control the auto-update feature;
2458 for a more detailed description refer to doc/README.update.
2460 - MTD Support (mtdparts command, UBI support)
2463 Adds the MTD device infrastructure from the Linux kernel.
2464 Needed for mtdparts command support.
2466 CONFIG_MTD_PARTITIONS
2468 Adds the MTD partitioning infrastructure from the Linux
2469 kernel. Needed for UBI support.
2473 Enable building of SPL globally.
2475 CONFIG_SPL_TEXT_BASE
2476 TEXT_BASE for linking the SPL binary.
2479 LDSCRIPT for linking the SPL binary.
2481 CONFIG_SPL_LIBCOMMON_SUPPORT
2482 Support for common/libcommon.o in SPL binary
2484 CONFIG_SPL_LIBDISK_SUPPORT
2485 Support for disk/libdisk.o in SPL binary
2487 CONFIG_SPL_I2C_SUPPORT
2488 Support for drivers/i2c/libi2c.o in SPL binary
2490 CONFIG_SPL_GPIO_SUPPORT
2491 Support for drivers/gpio/libgpio.o in SPL binary
2493 CONFIG_SPL_MMC_SUPPORT
2494 Support for drivers/mmc/libmmc.o in SPL binary
2496 CONFIG_SPL_SERIAL_SUPPORT
2497 Support for drivers/serial/libserial.o in SPL binary
2499 CONFIG_SPL_SPI_FLASH_SUPPORT
2500 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2502 CONFIG_SPL_SPI_SUPPORT
2503 Support for drivers/spi/libspi.o in SPL binary
2505 CONFIG_SPL_FAT_SUPPORT
2506 Support for fs/fat/libfat.o in SPL binary
2508 CONFIG_SPL_LIBGENERIC_SUPPORT
2509 Support for lib/libgeneric.o in SPL binary
2514 [so far only for SMDK2400 boards]
2516 - Modem support enable:
2517 CONFIG_MODEM_SUPPORT
2519 - RTS/CTS Flow control enable:
2522 - Modem debug support:
2523 CONFIG_MODEM_SUPPORT_DEBUG
2525 Enables debugging stuff (char screen[1024], dbg())
2526 for modem support. Useful only with BDI2000.
2528 - Interrupt support (PPC):
2530 There are common interrupt_init() and timer_interrupt()
2531 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2532 for CPU specific initialization. interrupt_init_cpu()
2533 should set decrementer_count to appropriate value. If
2534 CPU resets decrementer automatically after interrupt
2535 (ppc4xx) it should set decrementer_count to zero.
2536 timer_interrupt() calls timer_interrupt_cpu() for CPU
2537 specific handling. If board has watchdog / status_led
2538 / other_activity_monitor it works automatically from
2539 general timer_interrupt().
2543 In the target system modem support is enabled when a
2544 specific key (key combination) is pressed during
2545 power-on. Otherwise U-Boot will boot normally
2546 (autoboot). The key_pressed() function is called from
2547 board_init(). Currently key_pressed() is a dummy
2548 function, returning 1 and thus enabling modem
2551 If there are no modem init strings in the
2552 environment, U-Boot proceed to autoboot; the
2553 previous output (banner, info printfs) will be
2556 See also: doc/README.Modem
2558 Board initialization settings:
2559 ------------------------------
2561 During Initialization u-boot calls a number of board specific functions
2562 to allow the preparation of board specific prerequisites, e.g. pin setup
2563 before drivers are initialized. To enable these callbacks the
2564 following configuration macros have to be defined. Currently this is
2565 architecture specific, so please check arch/your_architecture/lib/board.c
2566 typically in board_init_f() and board_init_r().
2568 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2569 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2570 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2571 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2573 Configuration Settings:
2574 -----------------------
2576 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2577 undefine this when you're short of memory.
2579 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2580 width of the commands listed in the 'help' command output.
2582 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2583 prompt for user input.
2585 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2587 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2589 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2591 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2592 the application (usually a Linux kernel) when it is
2595 - CONFIG_SYS_BAUDRATE_TABLE:
2596 List of legal baudrate settings for this board.
2598 - CONFIG_SYS_CONSOLE_INFO_QUIET
2599 Suppress display of console information at boot.
2601 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2602 If the board specific function
2603 extern int overwrite_console (void);
2604 returns 1, the stdin, stderr and stdout are switched to the
2605 serial port, else the settings in the environment are used.
2607 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2608 Enable the call to overwrite_console().
2610 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2611 Enable overwrite of previous console environment settings.
2613 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2614 Begin and End addresses of the area used by the
2617 - CONFIG_SYS_ALT_MEMTEST:
2618 Enable an alternate, more extensive memory test.
2620 - CONFIG_SYS_MEMTEST_SCRATCH:
2621 Scratch address used by the alternate memory test
2622 You only need to set this if address zero isn't writeable
2624 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2625 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2626 this specified memory area will get subtracted from the top
2627 (end) of RAM and won't get "touched" at all by U-Boot. By
2628 fixing up gd->ram_size the Linux kernel should gets passed
2629 the now "corrected" memory size and won't touch it either.
2630 This should work for arch/ppc and arch/powerpc. Only Linux
2631 board ports in arch/powerpc with bootwrapper support that
2632 recalculate the memory size from the SDRAM controller setup
2633 will have to get fixed in Linux additionally.
2635 This option can be used as a workaround for the 440EPx/GRx
2636 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2639 WARNING: Please make sure that this value is a multiple of
2640 the Linux page size (normally 4k). If this is not the case,
2641 then the end address of the Linux memory will be located at a
2642 non page size aligned address and this could cause major
2645 - CONFIG_SYS_TFTP_LOADADDR:
2646 Default load address for network file downloads
2648 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2649 Enable temporary baudrate change while serial download
2651 - CONFIG_SYS_SDRAM_BASE:
2652 Physical start address of SDRAM. _Must_ be 0 here.
2654 - CONFIG_SYS_MBIO_BASE:
2655 Physical start address of Motherboard I/O (if using a
2658 - CONFIG_SYS_FLASH_BASE:
2659 Physical start address of Flash memory.
2661 - CONFIG_SYS_MONITOR_BASE:
2662 Physical start address of boot monitor code (set by
2663 make config files to be same as the text base address
2664 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2665 CONFIG_SYS_FLASH_BASE when booting from flash.
2667 - CONFIG_SYS_MONITOR_LEN:
2668 Size of memory reserved for monitor code, used to
2669 determine _at_compile_time_ (!) if the environment is
2670 embedded within the U-Boot image, or in a separate
2673 - CONFIG_SYS_MALLOC_LEN:
2674 Size of DRAM reserved for malloc() use.
2676 - CONFIG_SYS_BOOTM_LEN:
2677 Normally compressed uImages are limited to an
2678 uncompressed size of 8 MBytes. If this is not enough,
2679 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2680 to adjust this setting to your needs.
2682 - CONFIG_SYS_BOOTMAPSZ:
2683 Maximum size of memory mapped by the startup code of
2684 the Linux kernel; all data that must be processed by
2685 the Linux kernel (bd_info, boot arguments, FDT blob if
2686 used) must be put below this limit, unless "bootm_low"
2687 enviroment variable is defined and non-zero. In such case
2688 all data for the Linux kernel must be between "bootm_low"
2689 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2690 variable "bootm_mapsize" will override the value of
2691 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2692 then the value in "bootm_size" will be used instead.
2694 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2695 Enable initrd_high functionality. If defined then the
2696 initrd_high feature is enabled and the bootm ramdisk subcommand
2699 - CONFIG_SYS_BOOT_GET_CMDLINE:
2700 Enables allocating and saving kernel cmdline in space between
2701 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2703 - CONFIG_SYS_BOOT_GET_KBD:
2704 Enables allocating and saving a kernel copy of the bd_info in
2705 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2707 - CONFIG_SYS_MAX_FLASH_BANKS:
2708 Max number of Flash memory banks
2710 - CONFIG_SYS_MAX_FLASH_SECT:
2711 Max number of sectors on a Flash chip
2713 - CONFIG_SYS_FLASH_ERASE_TOUT:
2714 Timeout for Flash erase operations (in ms)
2716 - CONFIG_SYS_FLASH_WRITE_TOUT:
2717 Timeout for Flash write operations (in ms)
2719 - CONFIG_SYS_FLASH_LOCK_TOUT
2720 Timeout for Flash set sector lock bit operation (in ms)
2722 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2723 Timeout for Flash clear lock bits operation (in ms)
2725 - CONFIG_SYS_FLASH_PROTECTION
2726 If defined, hardware flash sectors protection is used
2727 instead of U-Boot software protection.
2729 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2731 Enable TFTP transfers directly to flash memory;
2732 without this option such a download has to be
2733 performed in two steps: (1) download to RAM, and (2)
2734 copy from RAM to flash.
2736 The two-step approach is usually more reliable, since
2737 you can check if the download worked before you erase
2738 the flash, but in some situations (when system RAM is
2739 too limited to allow for a temporary copy of the
2740 downloaded image) this option may be very useful.
2742 - CONFIG_SYS_FLASH_CFI:
2743 Define if the flash driver uses extra elements in the
2744 common flash structure for storing flash geometry.
2746 - CONFIG_FLASH_CFI_DRIVER
2747 This option also enables the building of the cfi_flash driver
2748 in the drivers directory
2750 - CONFIG_FLASH_CFI_MTD
2751 This option enables the building of the cfi_mtd driver
2752 in the drivers directory. The driver exports CFI flash
2755 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2756 Use buffered writes to flash.
2758 - CONFIG_FLASH_SPANSION_S29WS_N
2759 s29ws-n MirrorBit flash has non-standard addresses for buffered
2762 - CONFIG_SYS_FLASH_QUIET_TEST
2763 If this option is defined, the common CFI flash doesn't
2764 print it's warning upon not recognized FLASH banks. This
2765 is useful, if some of the configured banks are only
2766 optionally available.
2768 - CONFIG_FLASH_SHOW_PROGRESS
2769 If defined (must be an integer), print out countdown
2770 digits and dots. Recommended value: 45 (9..1) for 80
2771 column displays, 15 (3..1) for 40 column displays.
2773 - CONFIG_SYS_RX_ETH_BUFFER:
2774 Defines the number of Ethernet receive buffers. On some
2775 Ethernet controllers it is recommended to set this value
2776 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2777 buffers can be full shortly after enabling the interface
2778 on high Ethernet traffic.
2779 Defaults to 4 if not defined.
2781 - CONFIG_ENV_MAX_ENTRIES
2783 Maximum number of entries in the hash table that is used
2784 internally to store the environment settings. The default
2785 setting is supposed to be generous and should work in most
2786 cases. This setting can be used to tune behaviour; see
2787 lib/hashtable.c for details.
2789 The following definitions that deal with the placement and management
2790 of environment data (variable area); in general, we support the
2791 following configurations:
2793 - CONFIG_BUILD_ENVCRC:
2795 Builds up envcrc with the target environment so that external utils
2796 may easily extract it and embed it in final U-Boot images.
2798 - CONFIG_ENV_IS_IN_FLASH:
2800 Define this if the environment is in flash memory.
2802 a) The environment occupies one whole flash sector, which is
2803 "embedded" in the text segment with the U-Boot code. This
2804 happens usually with "bottom boot sector" or "top boot
2805 sector" type flash chips, which have several smaller
2806 sectors at the start or the end. For instance, such a
2807 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2808 such a case you would place the environment in one of the
2809 4 kB sectors - with U-Boot code before and after it. With
2810 "top boot sector" type flash chips, you would put the
2811 environment in one of the last sectors, leaving a gap
2812 between U-Boot and the environment.
2814 - CONFIG_ENV_OFFSET:
2816 Offset of environment data (variable area) to the
2817 beginning of flash memory; for instance, with bottom boot
2818 type flash chips the second sector can be used: the offset
2819 for this sector is given here.
2821 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2825 This is just another way to specify the start address of
2826 the flash sector containing the environment (instead of
2829 - CONFIG_ENV_SECT_SIZE:
2831 Size of the sector containing the environment.
2834 b) Sometimes flash chips have few, equal sized, BIG sectors.
2835 In such a case you don't want to spend a whole sector for
2840 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2841 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2842 of this flash sector for the environment. This saves
2843 memory for the RAM copy of the environment.
2845 It may also save flash memory if you decide to use this
2846 when your environment is "embedded" within U-Boot code,
2847 since then the remainder of the flash sector could be used
2848 for U-Boot code. It should be pointed out that this is
2849 STRONGLY DISCOURAGED from a robustness point of view:
2850 updating the environment in flash makes it always
2851 necessary to erase the WHOLE sector. If something goes
2852 wrong before the contents has been restored from a copy in
2853 RAM, your target system will be dead.
2855 - CONFIG_ENV_ADDR_REDUND
2856 CONFIG_ENV_SIZE_REDUND
2858 These settings describe a second storage area used to hold
2859 a redundant copy of the environment data, so that there is
2860 a valid backup copy in case there is a power failure during
2861 a "saveenv" operation.
2863 BE CAREFUL! Any changes to the flash layout, and some changes to the
2864 source code will make it necessary to adapt <board>/u-boot.lds*
2868 - CONFIG_ENV_IS_IN_NVRAM:
2870 Define this if you have some non-volatile memory device
2871 (NVRAM, battery buffered SRAM) which you want to use for the
2877 These two #defines are used to determine the memory area you
2878 want to use for environment. It is assumed that this memory
2879 can just be read and written to, without any special
2882 BE CAREFUL! The first access to the environment happens quite early
2883 in U-Boot initalization (when we try to get the setting of for the
2884 console baudrate). You *MUST* have mapped your NVRAM area then, or
2887 Please note that even with NVRAM we still use a copy of the
2888 environment in RAM: we could work on NVRAM directly, but we want to
2889 keep settings there always unmodified except somebody uses "saveenv"
2890 to save the current settings.
2893 - CONFIG_ENV_IS_IN_EEPROM:
2895 Use this if you have an EEPROM or similar serial access
2896 device and a driver for it.
2898 - CONFIG_ENV_OFFSET:
2901 These two #defines specify the offset and size of the
2902 environment area within the total memory of your EEPROM.
2904 - CONFIG_SYS_I2C_EEPROM_ADDR:
2905 If defined, specified the chip address of the EEPROM device.
2906 The default address is zero.
2908 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2909 If defined, the number of bits used to address bytes in a
2910 single page in the EEPROM device. A 64 byte page, for example
2911 would require six bits.
2913 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2914 If defined, the number of milliseconds to delay between
2915 page writes. The default is zero milliseconds.
2917 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2918 The length in bytes of the EEPROM memory array address. Note
2919 that this is NOT the chip address length!
2921 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2922 EEPROM chips that implement "address overflow" are ones
2923 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2924 address and the extra bits end up in the "chip address" bit
2925 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2928 Note that we consider the length of the address field to
2929 still be one byte because the extra address bits are hidden
2930 in the chip address.
2932 - CONFIG_SYS_EEPROM_SIZE:
2933 The size in bytes of the EEPROM device.
2935 - CONFIG_ENV_EEPROM_IS_ON_I2C
2936 define this, if you have I2C and SPI activated, and your
2937 EEPROM, which holds the environment, is on the I2C bus.
2939 - CONFIG_I2C_ENV_EEPROM_BUS
2940 if you have an Environment on an EEPROM reached over
2941 I2C muxes, you can define here, how to reach this
2942 EEPROM. For example:
2944 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2946 EEPROM which holds the environment, is reached over
2947 a pca9547 i2c mux with address 0x70, channel 3.
2949 - CONFIG_ENV_IS_IN_DATAFLASH:
2951 Define this if you have a DataFlash memory device which you
2952 want to use for the environment.
2954 - CONFIG_ENV_OFFSET:
2958 These three #defines specify the offset and size of the
2959 environment area within the total memory of your DataFlash placed
2960 at the specified address.
2962 - CONFIG_ENV_IS_IN_NAND:
2964 Define this if you have a NAND device which you want to use
2965 for the environment.
2967 - CONFIG_ENV_OFFSET:
2970 These two #defines specify the offset and size of the environment
2971 area within the first NAND device. CONFIG_ENV_OFFSET must be
2972 aligned to an erase block boundary.
2974 - CONFIG_ENV_OFFSET_REDUND (optional):
2976 This setting describes a second storage area of CONFIG_ENV_SIZE
2977 size used to hold a redundant copy of the environment data, so
2978 that there is a valid backup copy in case there is a power failure
2979 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2980 aligned to an erase block boundary.
2982 - CONFIG_ENV_RANGE (optional):
2984 Specifies the length of the region in which the environment
2985 can be written. This should be a multiple of the NAND device's
2986 block size. Specifying a range with more erase blocks than
2987 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2988 the range to be avoided.
2990 - CONFIG_ENV_OFFSET_OOB (optional):
2992 Enables support for dynamically retrieving the offset of the
2993 environment from block zero's out-of-band data. The
2994 "nand env.oob" command can be used to record this offset.
2995 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2996 using CONFIG_ENV_OFFSET_OOB.
2998 - CONFIG_NAND_ENV_DST
3000 Defines address in RAM to which the nand_spl code should copy the
3001 environment. If redundant environment is used, it will be copied to
3002 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3004 - CONFIG_SYS_SPI_INIT_OFFSET
3006 Defines offset to the initial SPI buffer area in DPRAM. The
3007 area is used at an early stage (ROM part) if the environment
3008 is configured to reside in the SPI EEPROM: We need a 520 byte
3009 scratch DPRAM area. It is used between the two initialization
3010 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3011 to be a good choice since it makes it far enough from the
3012 start of the data area as well as from the stack pointer.
3014 Please note that the environment is read-only until the monitor
3015 has been relocated to RAM and a RAM copy of the environment has been
3016 created; also, when using EEPROM you will have to use getenv_f()
3017 until then to read environment variables.
3019 The environment is protected by a CRC32 checksum. Before the monitor
3020 is relocated into RAM, as a result of a bad CRC you will be working
3021 with the compiled-in default environment - *silently*!!! [This is
3022 necessary, because the first environment variable we need is the
3023 "baudrate" setting for the console - if we have a bad CRC, we don't
3024 have any device yet where we could complain.]
3026 Note: once the monitor has been relocated, then it will complain if
3027 the default environment is used; a new CRC is computed as soon as you
3028 use the "saveenv" command to store a valid environment.
3030 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3031 Echo the inverted Ethernet link state to the fault LED.
3033 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3034 also needs to be defined.
3036 - CONFIG_SYS_FAULT_MII_ADDR:
3037 MII address of the PHY to check for the Ethernet link state.
3039 - CONFIG_NS16550_MIN_FUNCTIONS:
3040 Define this if you desire to only have use of the NS16550_init
3041 and NS16550_putc functions for the serial driver located at
3042 drivers/serial/ns16550.c. This option is useful for saving
3043 space for already greatly restricted images, including but not
3044 limited to NAND_SPL configurations.
3046 Low Level (hardware related) configuration options:
3047 ---------------------------------------------------
3049 - CONFIG_SYS_CACHELINE_SIZE:
3050 Cache Line Size of the CPU.
3052 - CONFIG_SYS_DEFAULT_IMMR:
3053 Default address of the IMMR after system reset.
3055 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3056 and RPXsuper) to be able to adjust the position of
3057 the IMMR register after a reset.
3059 - CONFIG_SYS_CCSRBAR_DEFAULT:
3060 Default (power-on reset) physical address of CCSR on Freescale
3063 - CONFIG_SYS_CCSRBAR:
3064 Virtual address of CCSR. On a 32-bit build, this is typically
3065 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3067 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3068 for cross-platform code that uses that macro instead.
3070 - CONFIG_SYS_CCSRBAR_PHYS:
3071 Physical address of CCSR. CCSR can be relocated to a new
3072 physical address, if desired. In this case, this macro should
3073 be set to that address. Otherwise, it should be set to the
3074 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3075 is typically relocated on 36-bit builds. It is recommended
3076 that this macro be defined via the _HIGH and _LOW macros:
3078 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3079 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3081 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3082 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3083 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3084 used in assembly code, so it must not contain typecasts or
3085 integer size suffixes (e.g. "ULL").
3087 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3088 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3089 used in assembly code, so it must not contain typecasts or
3090 integer size suffixes (e.g. "ULL").
3092 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3093 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3094 forced to a value that ensures that CCSR is not relocated.
3096 - Floppy Disk Support:
3097 CONFIG_SYS_FDC_DRIVE_NUMBER
3099 the default drive number (default value 0)
3101 CONFIG_SYS_ISA_IO_STRIDE
3103 defines the spacing between FDC chipset registers
3106 CONFIG_SYS_ISA_IO_OFFSET
3108 defines the offset of register from address. It
3109 depends on which part of the data bus is connected to
3110 the FDC chipset. (default value 0)
3112 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3113 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3116 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3117 fdc_hw_init() is called at the beginning of the FDC
3118 setup. fdc_hw_init() must be provided by the board
3119 source code. It is used to make hardware dependant
3123 Most IDE controllers were designed to be connected with PCI
3124 interface. Only few of them were designed for AHB interface.
3125 When software is doing ATA command and data transfer to
3126 IDE devices through IDE-AHB controller, some additional
3127 registers accessing to these kind of IDE-AHB controller
3130 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3131 DO NOT CHANGE unless you know exactly what you're
3132 doing! (11-4) [MPC8xx/82xx systems only]
3134 - CONFIG_SYS_INIT_RAM_ADDR:
3136 Start address of memory area that can be used for
3137 initial data and stack; please note that this must be
3138 writable memory that is working WITHOUT special
3139 initialization, i. e. you CANNOT use normal RAM which
3140 will become available only after programming the
3141 memory controller and running certain initialization
3144 U-Boot uses the following memory types:
3145 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3146 - MPC824X: data cache
3147 - PPC4xx: data cache
3149 - CONFIG_SYS_GBL_DATA_OFFSET:
3151 Offset of the initial data structure in the memory
3152 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3153 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3154 data is located at the end of the available space
3155 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3156 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3157 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3158 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3161 On the MPC824X (or other systems that use the data
3162 cache for initial memory) the address chosen for
3163 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3164 point to an otherwise UNUSED address space between
3165 the top of RAM and the start of the PCI space.
3167 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3169 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3171 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3173 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3175 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3177 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3179 - CONFIG_SYS_OR_TIMING_SDRAM:
3182 - CONFIG_SYS_MAMR_PTA:
3183 periodic timer for refresh
3185 - CONFIG_SYS_DER: Debug Event Register (37-47)
3187 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3188 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3189 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3190 CONFIG_SYS_BR1_PRELIM:
3191 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3193 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3194 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3195 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3196 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3198 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3199 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3200 Machine Mode Register and Memory Periodic Timer
3201 Prescaler definitions (SDRAM timing)
3203 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3204 enable I2C microcode relocation patch (MPC8xx);
3205 define relocation offset in DPRAM [DSP2]
3207 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3208 enable SMC microcode relocation patch (MPC8xx);
3209 define relocation offset in DPRAM [SMC1]
3211 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3212 enable SPI microcode relocation patch (MPC8xx);
3213 define relocation offset in DPRAM [SCC4]
3215 - CONFIG_SYS_USE_OSCCLK:
3216 Use OSCM clock mode on MBX8xx board. Be careful,
3217 wrong setting might damage your board. Read
3218 doc/README.MBX before setting this variable!
3220 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3221 Offset of the bootmode word in DPRAM used by post
3222 (Power On Self Tests). This definition overrides
3223 #define'd default value in commproc.h resp.
3226 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3227 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3228 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3229 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3230 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3231 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3232 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3233 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3234 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3236 - CONFIG_PCI_DISABLE_PCIE:
3237 Disable PCI-Express on systems where it is supported but not
3241 Chip has SRIO or not
3244 Board has SRIO 1 port available
3247 Board has SRIO 2 port available
3249 - CONFIG_SYS_SRIOn_MEM_VIRT:
3250 Virtual Address of SRIO port 'n' memory region
3252 - CONFIG_SYS_SRIOn_MEM_PHYS:
3253 Physical Address of SRIO port 'n' memory region
3255 - CONFIG_SYS_SRIOn_MEM_SIZE:
3256 Size of SRIO port 'n' memory region
3258 - CONFIG_SYS_NDFC_16
3259 Defined to tell the NDFC that the NAND chip is using a
3262 - CONFIG_SYS_NDFC_EBC0_CFG
3263 Sets the EBC0_CFG register for the NDFC. If not defined
3264 a default value will be used.
3267 Get DDR timing information from an I2C EEPROM. Common
3268 with pluggable memory modules such as SODIMMs
3271 I2C address of the SPD EEPROM
3273 - CONFIG_SYS_SPD_BUS_NUM
3274 If SPD EEPROM is on an I2C bus other than the first
3275 one, specify here. Note that the value must resolve
3276 to something your driver can deal with.
3278 - CONFIG_SYS_DDR_RAW_TIMING
3279 Get DDR timing information from other than SPD. Common with
3280 soldered DDR chips onboard without SPD. DDR raw timing
3281 parameters are extracted from datasheet and hard-coded into
3282 header files or board specific files.
3284 - CONFIG_FSL_DDR_INTERACTIVE
3285 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3287 - CONFIG_SYS_83XX_DDR_USES_CS0
3288 Only for 83xx systems. If specified, then DDR should
3289 be configured using CS0 and CS1 instead of CS2 and CS3.
3291 - CONFIG_ETHER_ON_FEC[12]
3292 Define to enable FEC[12] on a 8xx series processor.
3294 - CONFIG_FEC[12]_PHY
3295 Define to the hardcoded PHY address which corresponds
3296 to the given FEC; i. e.
3297 #define CONFIG_FEC1_PHY 4
3298 means that the PHY with address 4 is connected to FEC1
3300 When set to -1, means to probe for first available.
3302 - CONFIG_FEC[12]_PHY_NORXERR
3303 The PHY does not have a RXERR line (RMII only).
3304 (so program the FEC to ignore it).
3307 Enable RMII mode for all FECs.
3308 Note that this is a global option, we can't
3309 have one FEC in standard MII mode and another in RMII mode.
3311 - CONFIG_CRC32_VERIFY
3312 Add a verify option to the crc32 command.
3315 => crc32 -v <address> <count> <crc32>
3317 Where address/count indicate a memory area
3318 and crc32 is the correct crc32 which the
3322 Add the "loopw" memory command. This only takes effect if
3323 the memory commands are activated globally (CONFIG_CMD_MEM).
3326 Add the "mdc" and "mwc" memory commands. These are cyclic
3331 This command will print 4 bytes (10,11,12,13) each 500 ms.
3333 => mwc.l 100 12345678 10
3334 This command will write 12345678 to address 100 all 10 ms.
3336 This only takes effect if the memory commands are activated
3337 globally (CONFIG_CMD_MEM).
3339 - CONFIG_SKIP_LOWLEVEL_INIT
3340 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3341 low level initializations (like setting up the memory
3342 controller) are omitted and/or U-Boot does not
3343 relocate itself into RAM.
3345 Normally this variable MUST NOT be defined. The only
3346 exception is when U-Boot is loaded (to RAM) by some
3347 other boot loader or by a debugger which performs
3348 these initializations itself.
3351 Modifies the behaviour of start.S when compiling a loader
3352 that is executed before the actual U-Boot. E.g. when
3353 compiling a NAND SPL.
3355 - CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3356 define this, if you want to read first the oob data
3357 and then the data. This is used for example on
3360 - CONFIG_USE_ARCH_MEMCPY
3361 CONFIG_USE_ARCH_MEMSET
3362 If these options are used a optimized version of memcpy/memset will
3363 be used if available. These functions may be faster under some
3364 conditions but may increase the binary size.
3366 Freescale QE/FMAN Firmware Support:
3367 -----------------------------------
3369 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3370 loading of "firmware", which is encoded in the QE firmware binary format.
3371 This firmware often needs to be loaded during U-Boot booting, so macros
3372 are used to identify the storage device (NOR flash, SPI, etc) and the address
3375 - CONFIG_SYS_QE_FMAN_FW_ADDR
3376 The address in the storage device where the firmware is located. The
3377 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3380 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3381 The maximum possible size of the firmware. The firmware binary format
3382 has a field that specifies the actual size of the firmware, but it
3383 might not be possible to read any part of the firmware unless some
3384 local storage is allocated to hold the entire firmware first.
3386 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3387 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3388 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3389 virtual address in NOR flash.
3391 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3392 Specifies that QE/FMAN firmware is located in NAND flash.
3393 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3395 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3396 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3397 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3399 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3400 Specifies that QE/FMAN firmware is located on the primary SPI
3401 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3404 Building the Software:
3405 ======================
3407 Building U-Boot has been tested in several native build environments
3408 and in many different cross environments. Of course we cannot support
3409 all possibly existing versions of cross development tools in all
3410 (potentially obsolete) versions. In case of tool chain problems we
3411 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3412 which is extensively used to build and test U-Boot.
3414 If you are not using a native environment, it is assumed that you
3415 have GNU cross compiling tools available in your path. In this case,
3416 you must set the environment variable CROSS_COMPILE in your shell.
3417 Note that no changes to the Makefile or any other source files are
3418 necessary. For example using the ELDK on a 4xx CPU, please enter:
3420 $ CROSS_COMPILE=ppc_4xx-
3421 $ export CROSS_COMPILE
3423 Note: If you wish to generate Windows versions of the utilities in
3424 the tools directory you can use the MinGW toolchain
3425 (http://www.mingw.org). Set your HOST tools to the MinGW
3426 toolchain and execute 'make tools'. For example:
3428 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3430 Binaries such as tools/mkimage.exe will be created which can
3431 be executed on computers running Windows.
3433 U-Boot is intended to be simple to build. After installing the
3434 sources you must configure U-Boot for one specific board type. This
3439 where "NAME_config" is the name of one of the existing configu-
3440 rations; see the main Makefile for supported names.
3442 Note: for some board special configuration names may exist; check if
3443 additional information is available from the board vendor; for
3444 instance, the TQM823L systems are available without (standard)
3445 or with LCD support. You can select such additional "features"
3446 when choosing the configuration, i. e.
3449 - will configure for a plain TQM823L, i. e. no LCD support
3451 make TQM823L_LCD_config
3452 - will configure for a TQM823L with U-Boot console on LCD
3457 Finally, type "make all", and you should get some working U-Boot
3458 images ready for download to / installation on your system:
3460 - "u-boot.bin" is a raw binary image
3461 - "u-boot" is an image in ELF binary format
3462 - "u-boot.srec" is in Motorola S-Record format
3464 By default the build is performed locally and the objects are saved
3465 in the source directory. One of the two methods can be used to change
3466 this behavior and build U-Boot to some external directory:
3468 1. Add O= to the make command line invocations:
3470 make O=/tmp/build distclean
3471 make O=/tmp/build NAME_config
3472 make O=/tmp/build all
3474 2. Set environment variable BUILD_DIR to point to the desired location:
3476 export BUILD_DIR=/tmp/build
3481 Note that the command line "O=" setting overrides the BUILD_DIR environment
3485 Please be aware that the Makefiles assume you are using GNU make, so
3486 for instance on NetBSD you might need to use "gmake" instead of
3490 If the system board that you have is not listed, then you will need
3491 to port U-Boot to your hardware platform. To do this, follow these
3494 1. Add a new configuration option for your board to the toplevel
3495 "Makefile" and to the "MAKEALL" script, using the existing
3496 entries as examples. Note that here and at many other places
3497 boards and other names are listed in alphabetical sort order. Please
3499 2. Create a new directory to hold your board specific code. Add any
3500 files you need. In your board directory, you will need at least
3501 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3502 3. Create a new configuration file "include/configs/<board>.h" for
3504 3. If you're porting U-Boot to a new CPU, then also create a new
3505 directory to hold your CPU specific code. Add any files you need.
3506 4. Run "make <board>_config" with your new name.
3507 5. Type "make", and you should get a working "u-boot.srec" file
3508 to be installed on your target system.
3509 6. Debug and solve any problems that might arise.
3510 [Of course, this last step is much harder than it sounds.]
3513 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3514 ==============================================================
3516 If you have modified U-Boot sources (for instance added a new board
3517 or support for new devices, a new CPU, etc.) you are expected to
3518 provide feedback to the other developers. The feedback normally takes
3519 the form of a "patch", i. e. a context diff against a certain (latest
3520 official or latest in the git repository) version of U-Boot sources.
3522 But before you submit such a patch, please verify that your modifi-
3523 cation did not break existing code. At least make sure that *ALL* of
3524 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3525 just run the "MAKEALL" script, which will configure and build U-Boot
3526 for ALL supported system. Be warned, this will take a while. You can
3527 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3528 environment variable to the script, i. e. to use the ELDK cross tools
3531 CROSS_COMPILE=ppc_8xx- MAKEALL
3533 or to build on a native PowerPC system you can type
3535 CROSS_COMPILE=' ' MAKEALL
3537 When using the MAKEALL script, the default behaviour is to build
3538 U-Boot in the source directory. This location can be changed by
3539 setting the BUILD_DIR environment variable. Also, for each target
3540 built, the MAKEALL script saves two log files (<target>.ERR and
3541 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3542 location can be changed by setting the MAKEALL_LOGDIR environment
3543 variable. For example:
3545 export BUILD_DIR=/tmp/build
3546 export MAKEALL_LOGDIR=/tmp/log
3547 CROSS_COMPILE=ppc_8xx- MAKEALL
3549 With the above settings build objects are saved in the /tmp/build,
3550 log files are saved in the /tmp/log and the source tree remains clean
3551 during the whole build process.
3554 See also "U-Boot Porting Guide" below.
3557 Monitor Commands - Overview:
3558 ============================
3560 go - start application at address 'addr'
3561 run - run commands in an environment variable
3562 bootm - boot application image from memory
3563 bootp - boot image via network using BootP/TFTP protocol
3564 tftpboot- boot image via network using TFTP protocol
3565 and env variables "ipaddr" and "serverip"
3566 (and eventually "gatewayip")
3567 tftpput - upload a file via network using TFTP protocol
3568 rarpboot- boot image via network using RARP/TFTP protocol
3569 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3570 loads - load S-Record file over serial line
3571 loadb - load binary file over serial line (kermit mode)
3573 mm - memory modify (auto-incrementing)
3574 nm - memory modify (constant address)
3575 mw - memory write (fill)
3577 cmp - memory compare
3578 crc32 - checksum calculation
3579 i2c - I2C sub-system
3580 sspi - SPI utility commands
3581 base - print or set address offset
3582 printenv- print environment variables
3583 setenv - set environment variables
3584 saveenv - save environment variables to persistent storage
3585 protect - enable or disable FLASH write protection
3586 erase - erase FLASH memory
3587 flinfo - print FLASH memory information
3588 bdinfo - print Board Info structure
3589 iminfo - print header information for application image
3590 coninfo - print console devices and informations
3591 ide - IDE sub-system
3592 loop - infinite loop on address range
3593 loopw - infinite write loop on address range
3594 mtest - simple RAM test
3595 icache - enable or disable instruction cache
3596 dcache - enable or disable data cache
3597 reset - Perform RESET of the CPU
3598 echo - echo args to console
3599 version - print monitor version
3600 help - print online help
3601 ? - alias for 'help'
3604 Monitor Commands - Detailed Description:
3605 ========================================
3609 For now: just type "help <command>".
3612 Environment Variables:
3613 ======================
3615 U-Boot supports user configuration using Environment Variables which
3616 can be made persistent by saving to Flash memory.
3618 Environment Variables are set using "setenv", printed using
3619 "printenv", and saved to Flash using "saveenv". Using "setenv"
3620 without a value can be used to delete a variable from the
3621 environment. As long as you don't save the environment you are
3622 working with an in-memory copy. In case the Flash area containing the
3623 environment is erased by accident, a default environment is provided.
3625 Some configuration options can be set using Environment Variables.
3627 List of environment variables (most likely not complete):
3629 baudrate - see CONFIG_BAUDRATE
3631 bootdelay - see CONFIG_BOOTDELAY
3633 bootcmd - see CONFIG_BOOTCOMMAND
3635 bootargs - Boot arguments when booting an RTOS image
3637 bootfile - Name of the image to load with TFTP
3639 bootm_low - Memory range available for image processing in the bootm
3640 command can be restricted. This variable is given as
3641 a hexadecimal number and defines lowest address allowed
3642 for use by the bootm command. See also "bootm_size"
3643 environment variable. Address defined by "bootm_low" is
3644 also the base of the initial memory mapping for the Linux
3645 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3648 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3649 This variable is given as a hexadecimal number and it
3650 defines the size of the memory region starting at base
3651 address bootm_low that is accessible by the Linux kernel
3652 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3653 as the default value if it is defined, and bootm_size is
3656 bootm_size - Memory range available for image processing in the bootm
3657 command can be restricted. This variable is given as
3658 a hexadecimal number and defines the size of the region
3659 allowed for use by the bootm command. See also "bootm_low"
3660 environment variable.
3662 updatefile - Location of the software update file on a TFTP server, used
3663 by the automatic software update feature. Please refer to
3664 documentation in doc/README.update for more details.
3666 autoload - if set to "no" (any string beginning with 'n'),
3667 "bootp" will just load perform a lookup of the
3668 configuration from the BOOTP server, but not try to
3669 load any image using TFTP
3671 autostart - if set to "yes", an image loaded using the "bootp",
3672 "rarpboot", "tftpboot" or "diskboot" commands will
3673 be automatically started (by internally calling
3676 If set to "no", a standalone image passed to the
3677 "bootm" command will be copied to the load address
3678 (and eventually uncompressed), but NOT be started.
3679 This can be used to load and uncompress arbitrary
3682 fdt_high - if set this restricts the maximum address that the
3683 flattened device tree will be copied into upon boot.
3684 For example, if you have a system with 1 GB memory
3685 at physical address 0x10000000, while Linux kernel
3686 only recognizes the first 704 MB as low memory, you
3687 may need to set fdt_high as 0x3C000000 to have the
3688 device tree blob be copied to the maximum address
3689 of the 704 MB low memory, so that Linux kernel can
3690 access it during the boot procedure.
3692 If this is set to the special value 0xFFFFFFFF then
3693 the fdt will not be copied at all on boot. For this
3694 to work it must reside in writable memory, have
3695 sufficient padding on the end of it for u-boot to
3696 add the information it needs into it, and the memory
3697 must be accessible by the kernel.
3699 fdtcontroladdr- if set this is the address of the control flattened
3700 device tree used by U-Boot when CONFIG_OF_CONTROL is
3703 i2cfast - (PPC405GP|PPC405EP only)
3704 if set to 'y' configures Linux I2C driver for fast
3705 mode (400kHZ). This environment variable is used in
3706 initialization code. So, for changes to be effective
3707 it must be saved and board must be reset.
3709 initrd_high - restrict positioning of initrd images:
3710 If this variable is not set, initrd images will be
3711 copied to the highest possible address in RAM; this
3712 is usually what you want since it allows for
3713 maximum initrd size. If for some reason you want to
3714 make sure that the initrd image is loaded below the
3715 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3716 variable to a value of "no" or "off" or "0".
3717 Alternatively, you can set it to a maximum upper
3718 address to use (U-Boot will still check that it
3719 does not overwrite the U-Boot stack and data).
3721 For instance, when you have a system with 16 MB
3722 RAM, and want to reserve 4 MB from use by Linux,
3723 you can do this by adding "mem=12M" to the value of
3724 the "bootargs" variable. However, now you must make
3725 sure that the initrd image is placed in the first
3726 12 MB as well - this can be done with
3728 setenv initrd_high 00c00000
3730 If you set initrd_high to 0xFFFFFFFF, this is an
3731 indication to U-Boot that all addresses are legal
3732 for the Linux kernel, including addresses in flash
3733 memory. In this case U-Boot will NOT COPY the
3734 ramdisk at all. This may be useful to reduce the
3735 boot time on your system, but requires that this
3736 feature is supported by your Linux kernel.
3738 ipaddr - IP address; needed for tftpboot command
3740 loadaddr - Default load address for commands like "bootp",
3741 "rarpboot", "tftpboot", "loadb" or "diskboot"
3743 loads_echo - see CONFIG_LOADS_ECHO
3745 serverip - TFTP server IP address; needed for tftpboot command
3747 bootretry - see CONFIG_BOOT_RETRY_TIME
3749 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3751 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3753 ethprime - controls which interface is used first.
3755 ethact - controls which interface is currently active.
3756 For example you can do the following
3758 => setenv ethact FEC
3759 => ping 192.168.0.1 # traffic sent on FEC
3760 => setenv ethact SCC
3761 => ping 10.0.0.1 # traffic sent on SCC
3763 ethrotate - When set to "no" U-Boot does not go through all
3764 available network interfaces.
3765 It just stays at the currently selected interface.
3767 netretry - When set to "no" each network operation will
3768 either succeed or fail without retrying.
3769 When set to "once" the network operation will
3770 fail when all the available network interfaces
3771 are tried once without success.
3772 Useful on scripts which control the retry operation
3775 npe_ucode - set load address for the NPE microcode
3777 tftpsrcport - If this is set, the value is used for TFTP's
3780 tftpdstport - If this is set, the value is used for TFTP's UDP
3781 destination port instead of the Well Know Port 69.
3783 tftpblocksize - Block size to use for TFTP transfers; if not set,
3784 we use the TFTP server's default block size
3786 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3787 seconds, minimum value is 1000 = 1 second). Defines
3788 when a packet is considered to be lost so it has to
3789 be retransmitted. The default is 5000 = 5 seconds.
3790 Lowering this value may make downloads succeed
3791 faster in networks with high packet loss rates or
3792 with unreliable TFTP servers.
3794 vlan - When set to a value < 4095 the traffic over
3795 Ethernet is encapsulated/received over 802.1q
3798 The following image location variables contain the location of images
3799 used in booting. The "Image" column gives the role of the image and is
3800 not an environment variable name. The other columns are environment
3801 variable names. "File Name" gives the name of the file on a TFTP
3802 server, "RAM Address" gives the location in RAM the image will be
3803 loaded to, and "Flash Location" gives the image's address in NOR
3804 flash or offset in NAND flash.
3806 *Note* - these variables don't have to be defined for all boards, some
3807 boards currenlty use other variables for these purposes, and some
3808 boards use these variables for other purposes.
3810 Image File Name RAM Address Flash Location
3811 ----- --------- ----------- --------------
3812 u-boot u-boot u-boot_addr_r u-boot_addr
3813 Linux kernel bootfile kernel_addr_r kernel_addr
3814 device tree blob fdtfile fdt_addr_r fdt_addr
3815 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3817 The following environment variables may be used and automatically
3818 updated by the network boot commands ("bootp" and "rarpboot"),
3819 depending the information provided by your boot server:
3821 bootfile - see above
3822 dnsip - IP address of your Domain Name Server
3823 dnsip2 - IP address of your secondary Domain Name Server
3824 gatewayip - IP address of the Gateway (Router) to use
3825 hostname - Target hostname
3827 netmask - Subnet Mask
3828 rootpath - Pathname of the root filesystem on the NFS server
3829 serverip - see above
3832 There are two special Environment Variables:
3834 serial# - contains hardware identification information such
3835 as type string and/or serial number
3836 ethaddr - Ethernet address
3838 These variables can be set only once (usually during manufacturing of
3839 the board). U-Boot refuses to delete or overwrite these variables
3840 once they have been set once.
3843 Further special Environment Variables:
3845 ver - Contains the U-Boot version string as printed
3846 with the "version" command. This variable is
3847 readonly (see CONFIG_VERSION_VARIABLE).
3850 Please note that changes to some configuration parameters may take
3851 only effect after the next boot (yes, that's just like Windoze :-).
3854 Command Line Parsing:
3855 =====================
3857 There are two different command line parsers available with U-Boot:
3858 the old "simple" one, and the much more powerful "hush" shell:
3860 Old, simple command line parser:
3861 --------------------------------
3863 - supports environment variables (through setenv / saveenv commands)
3864 - several commands on one line, separated by ';'
3865 - variable substitution using "... ${name} ..." syntax
3866 - special characters ('$', ';') can be escaped by prefixing with '\',
3868 setenv bootcmd bootm \${address}
3869 - You can also escape text by enclosing in single apostrophes, for example:
3870 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3875 - similar to Bourne shell, with control structures like
3876 if...then...else...fi, for...do...done; while...do...done,
3877 until...do...done, ...
3878 - supports environment ("global") variables (through setenv / saveenv
3879 commands) and local shell variables (through standard shell syntax
3880 "name=value"); only environment variables can be used with "run"
3886 (1) If a command line (or an environment variable executed by a "run"
3887 command) contains several commands separated by semicolon, and
3888 one of these commands fails, then the remaining commands will be
3891 (2) If you execute several variables with one call to run (i. e.
3892 calling run with a list of variables as arguments), any failing
3893 command will cause "run" to terminate, i. e. the remaining
3894 variables are not executed.
3896 Note for Redundant Ethernet Interfaces:
3897 =======================================
3899 Some boards come with redundant Ethernet interfaces; U-Boot supports
3900 such configurations and is capable of automatic selection of a
3901 "working" interface when needed. MAC assignment works as follows:
3903 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3904 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3905 "eth1addr" (=>eth1), "eth2addr", ...
3907 If the network interface stores some valid MAC address (for instance
3908 in SROM), this is used as default address if there is NO correspon-
3909 ding setting in the environment; if the corresponding environment
3910 variable is set, this overrides the settings in the card; that means:
3912 o If the SROM has a valid MAC address, and there is no address in the
3913 environment, the SROM's address is used.
3915 o If there is no valid address in the SROM, and a definition in the
3916 environment exists, then the value from the environment variable is
3919 o If both the SROM and the environment contain a MAC address, and
3920 both addresses are the same, this MAC address is used.
3922 o If both the SROM and the environment contain a MAC address, and the
3923 addresses differ, the value from the environment is used and a
3926 o If neither SROM nor the environment contain a MAC address, an error
3929 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3930 will be programmed into hardware as part of the initialization process. This
3931 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3932 The naming convention is as follows:
3933 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3938 U-Boot is capable of booting (and performing other auxiliary operations on)
3939 images in two formats:
3941 New uImage format (FIT)
3942 -----------------------
3944 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3945 to Flattened Device Tree). It allows the use of images with multiple
3946 components (several kernels, ramdisks, etc.), with contents protected by
3947 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3953 Old image format is based on binary files which can be basically anything,
3954 preceded by a special header; see the definitions in include/image.h for
3955 details; basically, the header defines the following image properties:
3957 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3958 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3959 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3960 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3962 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3963 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3964 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3965 * Compression Type (uncompressed, gzip, bzip2)
3971 The header is marked by a special Magic Number, and both the header
3972 and the data portions of the image are secured against corruption by
3979 Although U-Boot should support any OS or standalone application
3980 easily, the main focus has always been on Linux during the design of
3983 U-Boot includes many features that so far have been part of some
3984 special "boot loader" code within the Linux kernel. Also, any
3985 "initrd" images to be used are no longer part of one big Linux image;
3986 instead, kernel and "initrd" are separate images. This implementation
3987 serves several purposes:
3989 - the same features can be used for other OS or standalone
3990 applications (for instance: using compressed images to reduce the
3991 Flash memory footprint)
3993 - it becomes much easier to port new Linux kernel versions because
3994 lots of low-level, hardware dependent stuff are done by U-Boot
3996 - the same Linux kernel image can now be used with different "initrd"
3997 images; of course this also means that different kernel images can
3998 be run with the same "initrd". This makes testing easier (you don't
3999 have to build a new "zImage.initrd" Linux image when you just
4000 change a file in your "initrd"). Also, a field-upgrade of the
4001 software is easier now.
4007 Porting Linux to U-Boot based systems:
4008 ---------------------------------------
4010 U-Boot cannot save you from doing all the necessary modifications to
4011 configure the Linux device drivers for use with your target hardware
4012 (no, we don't intend to provide a full virtual machine interface to
4015 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4017 Just make sure your machine specific header file (for instance
4018 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4019 Information structure as we define in include/asm-<arch>/u-boot.h,
4020 and make sure that your definition of IMAP_ADDR uses the same value
4021 as your U-Boot configuration in CONFIG_SYS_IMMR.
4024 Configuring the Linux kernel:
4025 -----------------------------
4027 No specific requirements for U-Boot. Make sure you have some root
4028 device (initial ramdisk, NFS) for your target system.
4031 Building a Linux Image:
4032 -----------------------
4034 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4035 not used. If you use recent kernel source, a new build target
4036 "uImage" will exist which automatically builds an image usable by
4037 U-Boot. Most older kernels also have support for a "pImage" target,
4038 which was introduced for our predecessor project PPCBoot and uses a
4039 100% compatible format.
4048 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4049 encapsulate a compressed Linux kernel image with header information,
4050 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4052 * build a standard "vmlinux" kernel image (in ELF binary format):
4054 * convert the kernel into a raw binary image:
4056 ${CROSS_COMPILE}-objcopy -O binary \
4057 -R .note -R .comment \
4058 -S vmlinux linux.bin
4060 * compress the binary image:
4064 * package compressed binary image for U-Boot:
4066 mkimage -A ppc -O linux -T kernel -C gzip \
4067 -a 0 -e 0 -n "Linux Kernel Image" \
4068 -d linux.bin.gz uImage
4071 The "mkimage" tool can also be used to create ramdisk images for use
4072 with U-Boot, either separated from the Linux kernel image, or
4073 combined into one file. "mkimage" encapsulates the images with a 64
4074 byte header containing information about target architecture,
4075 operating system, image type, compression method, entry points, time
4076 stamp, CRC32 checksums, etc.
4078 "mkimage" can be called in two ways: to verify existing images and
4079 print the header information, or to build new images.
4081 In the first form (with "-l" option) mkimage lists the information
4082 contained in the header of an existing U-Boot image; this includes
4083 checksum verification:
4085 tools/mkimage -l image
4086 -l ==> list image header information
4088 The second form (with "-d" option) is used to build a U-Boot image
4089 from a "data file" which is used as image payload:
4091 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4092 -n name -d data_file image
4093 -A ==> set architecture to 'arch'
4094 -O ==> set operating system to 'os'
4095 -T ==> set image type to 'type'
4096 -C ==> set compression type 'comp'
4097 -a ==> set load address to 'addr' (hex)
4098 -e ==> set entry point to 'ep' (hex)
4099 -n ==> set image name to 'name'
4100 -d ==> use image data from 'datafile'
4102 Right now, all Linux kernels for PowerPC systems use the same load
4103 address (0x00000000), but the entry point address depends on the
4106 - 2.2.x kernels have the entry point at 0x0000000C,
4107 - 2.3.x and later kernels have the entry point at 0x00000000.
4109 So a typical call to build a U-Boot image would read:
4111 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4112 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4113 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4114 > examples/uImage.TQM850L
4115 Image Name: 2.4.4 kernel for TQM850L
4116 Created: Wed Jul 19 02:34:59 2000
4117 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4118 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4119 Load Address: 0x00000000
4120 Entry Point: 0x00000000
4122 To verify the contents of the image (or check for corruption):
4124 -> tools/mkimage -l examples/uImage.TQM850L
4125 Image Name: 2.4.4 kernel for TQM850L
4126 Created: Wed Jul 19 02:34:59 2000
4127 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4128 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4129 Load Address: 0x00000000
4130 Entry Point: 0x00000000
4132 NOTE: for embedded systems where boot time is critical you can trade
4133 speed for memory and install an UNCOMPRESSED image instead: this
4134 needs more space in Flash, but boots much faster since it does not
4135 need to be uncompressed:
4137 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4138 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4139 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4140 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4141 > examples/uImage.TQM850L-uncompressed
4142 Image Name: 2.4.4 kernel for TQM850L
4143 Created: Wed Jul 19 02:34:59 2000
4144 Image Type: PowerPC Linux Kernel Image (uncompressed)
4145 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4146 Load Address: 0x00000000
4147 Entry Point: 0x00000000
4150 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4151 when your kernel is intended to use an initial ramdisk:
4153 -> tools/mkimage -n 'Simple Ramdisk Image' \
4154 > -A ppc -O linux -T ramdisk -C gzip \
4155 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4156 Image Name: Simple Ramdisk Image
4157 Created: Wed Jan 12 14:01:50 2000
4158 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4159 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4160 Load Address: 0x00000000
4161 Entry Point: 0x00000000
4164 Installing a Linux Image:
4165 -------------------------
4167 To downloading a U-Boot image over the serial (console) interface,
4168 you must convert the image to S-Record format:
4170 objcopy -I binary -O srec examples/image examples/image.srec
4172 The 'objcopy' does not understand the information in the U-Boot
4173 image header, so the resulting S-Record file will be relative to
4174 address 0x00000000. To load it to a given address, you need to
4175 specify the target address as 'offset' parameter with the 'loads'
4178 Example: install the image to address 0x40100000 (which on the
4179 TQM8xxL is in the first Flash bank):
4181 => erase 40100000 401FFFFF
4187 ## Ready for S-Record download ...
4188 ~>examples/image.srec
4189 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4191 15989 15990 15991 15992
4192 [file transfer complete]
4194 ## Start Addr = 0x00000000
4197 You can check the success of the download using the 'iminfo' command;
4198 this includes a checksum verification so you can be sure no data
4199 corruption happened:
4203 ## Checking Image at 40100000 ...
4204 Image Name: 2.2.13 for initrd on TQM850L
4205 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4206 Data Size: 335725 Bytes = 327 kB = 0 MB
4207 Load Address: 00000000
4208 Entry Point: 0000000c
4209 Verifying Checksum ... OK
4215 The "bootm" command is used to boot an application that is stored in
4216 memory (RAM or Flash). In case of a Linux kernel image, the contents
4217 of the "bootargs" environment variable is passed to the kernel as
4218 parameters. You can check and modify this variable using the
4219 "printenv" and "setenv" commands:
4222 => printenv bootargs
4223 bootargs=root=/dev/ram
4225 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4227 => printenv bootargs
4228 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4231 ## Booting Linux kernel at 40020000 ...
4232 Image Name: 2.2.13 for NFS on TQM850L
4233 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4234 Data Size: 381681 Bytes = 372 kB = 0 MB
4235 Load Address: 00000000
4236 Entry Point: 0000000c
4237 Verifying Checksum ... OK
4238 Uncompressing Kernel Image ... OK
4239 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
4240 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4241 time_init: decrementer frequency = 187500000/60
4242 Calibrating delay loop... 49.77 BogoMIPS
4243 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4246 If you want to boot a Linux kernel with initial RAM disk, you pass
4247 the memory addresses of both the kernel and the initrd image (PPBCOOT
4248 format!) to the "bootm" command:
4250 => imi 40100000 40200000
4252 ## Checking Image at 40100000 ...
4253 Image Name: 2.2.13 for initrd on TQM850L
4254 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4255 Data Size: 335725 Bytes = 327 kB = 0 MB
4256 Load Address: 00000000
4257 Entry Point: 0000000c
4258 Verifying Checksum ... OK
4260 ## Checking Image at 40200000 ...
4261 Image Name: Simple Ramdisk Image
4262 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4263 Data Size: 566530 Bytes = 553 kB = 0 MB
4264 Load Address: 00000000
4265 Entry Point: 00000000
4266 Verifying Checksum ... OK
4268 => bootm 40100000 40200000
4269 ## Booting Linux kernel at 40100000 ...
4270 Image Name: 2.2.13 for initrd on TQM850L
4271 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4272 Data Size: 335725 Bytes = 327 kB = 0 MB
4273 Load Address: 00000000
4274 Entry Point: 0000000c
4275 Verifying Checksum ... OK
4276 Uncompressing Kernel Image ... OK
4277 ## Loading RAMDisk Image at 40200000 ...
4278 Image Name: Simple Ramdisk Image
4279 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4280 Data Size: 566530 Bytes = 553 kB = 0 MB
4281 Load Address: 00000000
4282 Entry Point: 00000000
4283 Verifying Checksum ... OK
4284 Loading Ramdisk ... OK
4285 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
4286 Boot arguments: root=/dev/ram
4287 time_init: decrementer frequency = 187500000/60
4288 Calibrating delay loop... 49.77 BogoMIPS
4290 RAMDISK: Compressed image found at block 0
4291 VFS: Mounted root (ext2 filesystem).
4295 Boot Linux and pass a flat device tree:
4298 First, U-Boot must be compiled with the appropriate defines. See the section
4299 titled "Linux Kernel Interface" above for a more in depth explanation. The
4300 following is an example of how to start a kernel and pass an updated
4306 oft=oftrees/mpc8540ads.dtb
4307 => tftp $oftaddr $oft
4308 Speed: 1000, full duplex
4310 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4311 Filename 'oftrees/mpc8540ads.dtb'.
4312 Load address: 0x300000
4315 Bytes transferred = 4106 (100a hex)
4316 => tftp $loadaddr $bootfile
4317 Speed: 1000, full duplex
4319 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4321 Load address: 0x200000
4322 Loading:############
4324 Bytes transferred = 1029407 (fb51f hex)
4329 => bootm $loadaddr - $oftaddr
4330 ## Booting image at 00200000 ...
4331 Image Name: Linux-2.6.17-dirty
4332 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4333 Data Size: 1029343 Bytes = 1005.2 kB
4334 Load Address: 00000000
4335 Entry Point: 00000000
4336 Verifying Checksum ... OK
4337 Uncompressing Kernel Image ... OK
4338 Booting using flat device tree at 0x300000
4339 Using MPC85xx ADS machine description
4340 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4344 More About U-Boot Image Types:
4345 ------------------------------
4347 U-Boot supports the following image types:
4349 "Standalone Programs" are directly runnable in the environment
4350 provided by U-Boot; it is expected that (if they behave
4351 well) you can continue to work in U-Boot after return from
4352 the Standalone Program.
4353 "OS Kernel Images" are usually images of some Embedded OS which
4354 will take over control completely. Usually these programs
4355 will install their own set of exception handlers, device
4356 drivers, set up the MMU, etc. - this means, that you cannot
4357 expect to re-enter U-Boot except by resetting the CPU.
4358 "RAMDisk Images" are more or less just data blocks, and their
4359 parameters (address, size) are passed to an OS kernel that is
4361 "Multi-File Images" contain several images, typically an OS
4362 (Linux) kernel image and one or more data images like
4363 RAMDisks. This construct is useful for instance when you want
4364 to boot over the network using BOOTP etc., where the boot
4365 server provides just a single image file, but you want to get
4366 for instance an OS kernel and a RAMDisk image.
4368 "Multi-File Images" start with a list of image sizes, each
4369 image size (in bytes) specified by an "uint32_t" in network
4370 byte order. This list is terminated by an "(uint32_t)0".
4371 Immediately after the terminating 0 follow the images, one by
4372 one, all aligned on "uint32_t" boundaries (size rounded up to
4373 a multiple of 4 bytes).
4375 "Firmware Images" are binary images containing firmware (like
4376 U-Boot or FPGA images) which usually will be programmed to
4379 "Script files" are command sequences that will be executed by
4380 U-Boot's command interpreter; this feature is especially
4381 useful when you configure U-Boot to use a real shell (hush)
4382 as command interpreter.
4388 One of the features of U-Boot is that you can dynamically load and
4389 run "standalone" applications, which can use some resources of
4390 U-Boot like console I/O functions or interrupt services.
4392 Two simple examples are included with the sources:
4397 'examples/hello_world.c' contains a small "Hello World" Demo
4398 application; it is automatically compiled when you build U-Boot.
4399 It's configured to run at address 0x00040004, so you can play with it
4403 ## Ready for S-Record download ...
4404 ~>examples/hello_world.srec
4405 1 2 3 4 5 6 7 8 9 10 11 ...
4406 [file transfer complete]
4408 ## Start Addr = 0x00040004
4410 => go 40004 Hello World! This is a test.
4411 ## Starting application at 0x00040004 ...
4422 Hit any key to exit ...
4424 ## Application terminated, rc = 0x0
4426 Another example, which demonstrates how to register a CPM interrupt
4427 handler with the U-Boot code, can be found in 'examples/timer.c'.
4428 Here, a CPM timer is set up to generate an interrupt every second.
4429 The interrupt service routine is trivial, just printing a '.'
4430 character, but this is just a demo program. The application can be
4431 controlled by the following keys:
4433 ? - print current values og the CPM Timer registers
4434 b - enable interrupts and start timer
4435 e - stop timer and disable interrupts
4436 q - quit application
4439 ## Ready for S-Record download ...
4440 ~>examples/timer.srec
4441 1 2 3 4 5 6 7 8 9 10 11 ...
4442 [file transfer complete]
4444 ## Start Addr = 0x00040004
4447 ## Starting application at 0x00040004 ...
4450 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4453 [q, b, e, ?] Set interval 1000000 us
4456 [q, b, e, ?] ........
4457 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4460 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4463 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4466 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4468 [q, b, e, ?] ...Stopping timer
4470 [q, b, e, ?] ## Application terminated, rc = 0x0
4476 Over time, many people have reported problems when trying to use the
4477 "minicom" terminal emulation program for serial download. I (wd)
4478 consider minicom to be broken, and recommend not to use it. Under
4479 Unix, I recommend to use C-Kermit for general purpose use (and
4480 especially for kermit binary protocol download ("loadb" command), and
4481 use "cu" for S-Record download ("loads" command).
4483 Nevertheless, if you absolutely want to use it try adding this
4484 configuration to your "File transfer protocols" section:
4486 Name Program Name U/D FullScr IO-Red. Multi
4487 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4488 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4494 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4495 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4497 Building requires a cross environment; it is known to work on
4498 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4499 need gmake since the Makefiles are not compatible with BSD make).
4500 Note that the cross-powerpc package does not install include files;
4501 attempting to build U-Boot will fail because <machine/ansi.h> is
4502 missing. This file has to be installed and patched manually:
4504 # cd /usr/pkg/cross/powerpc-netbsd/include
4506 # ln -s powerpc machine
4507 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4508 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4510 Native builds *don't* work due to incompatibilities between native
4511 and U-Boot include files.
4513 Booting assumes that (the first part of) the image booted is a
4514 stage-2 loader which in turn loads and then invokes the kernel
4515 proper. Loader sources will eventually appear in the NetBSD source
4516 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4517 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4520 Implementation Internals:
4521 =========================
4523 The following is not intended to be a complete description of every
4524 implementation detail. However, it should help to understand the
4525 inner workings of U-Boot and make it easier to port it to custom
4529 Initial Stack, Global Data:
4530 ---------------------------
4532 The implementation of U-Boot is complicated by the fact that U-Boot
4533 starts running out of ROM (flash memory), usually without access to
4534 system RAM (because the memory controller is not initialized yet).
4535 This means that we don't have writable Data or BSS segments, and BSS
4536 is not initialized as zero. To be able to get a C environment working
4537 at all, we have to allocate at least a minimal stack. Implementation
4538 options for this are defined and restricted by the CPU used: Some CPU
4539 models provide on-chip memory (like the IMMR area on MPC8xx and
4540 MPC826x processors), on others (parts of) the data cache can be
4541 locked as (mis-) used as memory, etc.
4543 Chris Hallinan posted a good summary of these issues to the
4544 U-Boot mailing list:
4546 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4547 From: "Chris Hallinan" <clh@net1plus.com>
4548 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4551 Correct me if I'm wrong, folks, but the way I understand it
4552 is this: Using DCACHE as initial RAM for Stack, etc, does not
4553 require any physical RAM backing up the cache. The cleverness
4554 is that the cache is being used as a temporary supply of
4555 necessary storage before the SDRAM controller is setup. It's
4556 beyond the scope of this list to explain the details, but you
4557 can see how this works by studying the cache architecture and
4558 operation in the architecture and processor-specific manuals.
4560 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4561 is another option for the system designer to use as an
4562 initial stack/RAM area prior to SDRAM being available. Either
4563 option should work for you. Using CS 4 should be fine if your
4564 board designers haven't used it for something that would
4565 cause you grief during the initial boot! It is frequently not
4568 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4569 with your processor/board/system design. The default value
4570 you will find in any recent u-boot distribution in
4571 walnut.h should work for you. I'd set it to a value larger
4572 than your SDRAM module. If you have a 64MB SDRAM module, set
4573 it above 400_0000. Just make sure your board has no resources
4574 that are supposed to respond to that address! That code in
4575 start.S has been around a while and should work as is when
4576 you get the config right.
4581 It is essential to remember this, since it has some impact on the C
4582 code for the initialization procedures:
4584 * Initialized global data (data segment) is read-only. Do not attempt
4587 * Do not use any uninitialized global data (or implicitely initialized
4588 as zero data - BSS segment) at all - this is undefined, initiali-
4589 zation is performed later (when relocating to RAM).
4591 * Stack space is very limited. Avoid big data buffers or things like
4594 Having only the stack as writable memory limits means we cannot use
4595 normal global data to share information beween the code. But it
4596 turned out that the implementation of U-Boot can be greatly
4597 simplified by making a global data structure (gd_t) available to all
4598 functions. We could pass a pointer to this data as argument to _all_
4599 functions, but this would bloat the code. Instead we use a feature of
4600 the GCC compiler (Global Register Variables) to share the data: we
4601 place a pointer (gd) to the global data into a register which we
4602 reserve for this purpose.
4604 When choosing a register for such a purpose we are restricted by the
4605 relevant (E)ABI specifications for the current architecture, and by
4606 GCC's implementation.
4608 For PowerPC, the following registers have specific use:
4610 R2: reserved for system use
4611 R3-R4: parameter passing and return values
4612 R5-R10: parameter passing
4613 R13: small data area pointer
4617 (U-Boot also uses R12 as internal GOT pointer. r12
4618 is a volatile register so r12 needs to be reset when
4619 going back and forth between asm and C)
4621 ==> U-Boot will use R2 to hold a pointer to the global data
4623 Note: on PPC, we could use a static initializer (since the
4624 address of the global data structure is known at compile time),
4625 but it turned out that reserving a register results in somewhat
4626 smaller code - although the code savings are not that big (on
4627 average for all boards 752 bytes for the whole U-Boot image,
4628 624 text + 127 data).
4630 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4631 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4633 ==> U-Boot will use P3 to hold a pointer to the global data
4635 On ARM, the following registers are used:
4637 R0: function argument word/integer result
4638 R1-R3: function argument word
4640 R10: stack limit (used only if stack checking if enabled)
4641 R11: argument (frame) pointer
4642 R12: temporary workspace
4645 R15: program counter
4647 ==> U-Boot will use R8 to hold a pointer to the global data
4649 On Nios II, the ABI is documented here:
4650 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4652 ==> U-Boot will use gp to hold a pointer to the global data
4654 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4655 to access small data sections, so gp is free.
4657 On NDS32, the following registers are used:
4659 R0-R1: argument/return
4661 R15: temporary register for assembler
4662 R16: trampoline register
4663 R28: frame pointer (FP)
4664 R29: global pointer (GP)
4665 R30: link register (LP)
4666 R31: stack pointer (SP)
4667 PC: program counter (PC)
4669 ==> U-Boot will use R10 to hold a pointer to the global data
4671 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4672 or current versions of GCC may "optimize" the code too much.
4677 U-Boot runs in system state and uses physical addresses, i.e. the
4678 MMU is not used either for address mapping nor for memory protection.
4680 The available memory is mapped to fixed addresses using the memory
4681 controller. In this process, a contiguous block is formed for each
4682 memory type (Flash, SDRAM, SRAM), even when it consists of several
4683 physical memory banks.
4685 U-Boot is installed in the first 128 kB of the first Flash bank (on
4686 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4687 booting and sizing and initializing DRAM, the code relocates itself
4688 to the upper end of DRAM. Immediately below the U-Boot code some
4689 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4690 configuration setting]. Below that, a structure with global Board
4691 Info data is placed, followed by the stack (growing downward).
4693 Additionally, some exception handler code is copied to the low 8 kB
4694 of DRAM (0x00000000 ... 0x00001FFF).
4696 So a typical memory configuration with 16 MB of DRAM could look like
4699 0x0000 0000 Exception Vector code
4702 0x0000 2000 Free for Application Use
4708 0x00FB FF20 Monitor Stack (Growing downward)
4709 0x00FB FFAC Board Info Data and permanent copy of global data
4710 0x00FC 0000 Malloc Arena
4713 0x00FE 0000 RAM Copy of Monitor Code
4714 ... eventually: LCD or video framebuffer
4715 ... eventually: pRAM (Protected RAM - unchanged by reset)
4716 0x00FF FFFF [End of RAM]
4719 System Initialization:
4720 ----------------------
4722 In the reset configuration, U-Boot starts at the reset entry point
4723 (on most PowerPC systems at address 0x00000100). Because of the reset
4724 configuration for CS0# this is a mirror of the onboard Flash memory.
4725 To be able to re-map memory U-Boot then jumps to its link address.
4726 To be able to implement the initialization code in C, a (small!)
4727 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4728 which provide such a feature like MPC8xx or MPC8260), or in a locked
4729 part of the data cache. After that, U-Boot initializes the CPU core,
4730 the caches and the SIU.
4732 Next, all (potentially) available memory banks are mapped using a
4733 preliminary mapping. For example, we put them on 512 MB boundaries
4734 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4735 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4736 programmed for SDRAM access. Using the temporary configuration, a
4737 simple memory test is run that determines the size of the SDRAM
4740 When there is more than one SDRAM bank, and the banks are of
4741 different size, the largest is mapped first. For equal size, the first
4742 bank (CS2#) is mapped first. The first mapping is always for address
4743 0x00000000, with any additional banks following immediately to create
4744 contiguous memory starting from 0.
4746 Then, the monitor installs itself at the upper end of the SDRAM area
4747 and allocates memory for use by malloc() and for the global Board
4748 Info data; also, the exception vector code is copied to the low RAM
4749 pages, and the final stack is set up.
4751 Only after this relocation will you have a "normal" C environment;
4752 until that you are restricted in several ways, mostly because you are
4753 running from ROM, and because the code will have to be relocated to a
4757 U-Boot Porting Guide:
4758 ----------------------
4760 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4764 int main(int argc, char *argv[])
4766 sighandler_t no_more_time;
4768 signal(SIGALRM, no_more_time);
4769 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4771 if (available_money > available_manpower) {
4772 Pay consultant to port U-Boot;
4776 Download latest U-Boot source;
4778 Subscribe to u-boot mailing list;
4781 email("Hi, I am new to U-Boot, how do I get started?");
4784 Read the README file in the top level directory;
4785 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4786 Read applicable doc/*.README;
4787 Read the source, Luke;
4788 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4791 if (available_money > toLocalCurrency ($2500))
4794 Add a lot of aggravation and time;
4796 if (a similar board exists) { /* hopefully... */
4797 cp -a board/<similar> board/<myboard>
4798 cp include/configs/<similar>.h include/configs/<myboard>.h
4800 Create your own board support subdirectory;
4801 Create your own board include/configs/<myboard>.h file;
4803 Edit new board/<myboard> files
4804 Edit new include/configs/<myboard>.h
4809 Add / modify source code;
4813 email("Hi, I am having problems...");
4815 Send patch file to the U-Boot email list;
4816 if (reasonable critiques)
4817 Incorporate improvements from email list code review;
4819 Defend code as written;
4825 void no_more_time (int sig)
4834 All contributions to U-Boot should conform to the Linux kernel
4835 coding style; see the file "Documentation/CodingStyle" and the script
4836 "scripts/Lindent" in your Linux kernel source directory.
4838 Source files originating from a different project (for example the
4839 MTD subsystem) are generally exempt from these guidelines and are not
4840 reformated to ease subsequent migration to newer versions of those
4843 Please note that U-Boot is implemented in C (and to some small parts in
4844 Assembler); no C++ is used, so please do not use C++ style comments (//)
4847 Please also stick to the following formatting rules:
4848 - remove any trailing white space
4849 - use TAB characters for indentation and vertical alignment, not spaces
4850 - make sure NOT to use DOS '\r\n' line feeds
4851 - do not add more than 2 consecutive empty lines to source files
4852 - do not add trailing empty lines to source files
4854 Submissions which do not conform to the standards may be returned
4855 with a request to reformat the changes.
4861 Since the number of patches for U-Boot is growing, we need to
4862 establish some rules. Submissions which do not conform to these rules
4863 may be rejected, even when they contain important and valuable stuff.
4865 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4867 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4868 see http://lists.denx.de/mailman/listinfo/u-boot
4870 When you send a patch, please include the following information with
4873 * For bug fixes: a description of the bug and how your patch fixes
4874 this bug. Please try to include a way of demonstrating that the
4875 patch actually fixes something.
4877 * For new features: a description of the feature and your
4880 * A CHANGELOG entry as plaintext (separate from the patch)
4882 * For major contributions, your entry to the CREDITS file
4884 * When you add support for a new board, don't forget to add this
4885 board to the MAINTAINERS file, too.
4887 * If your patch adds new configuration options, don't forget to
4888 document these in the README file.
4890 * The patch itself. If you are using git (which is *strongly*
4891 recommended) you can easily generate the patch using the
4892 "git format-patch". If you then use "git send-email" to send it to
4893 the U-Boot mailing list, you will avoid most of the common problems
4894 with some other mail clients.
4896 If you cannot use git, use "diff -purN OLD NEW". If your version of
4897 diff does not support these options, then get the latest version of
4900 The current directory when running this command shall be the parent
4901 directory of the U-Boot source tree (i. e. please make sure that
4902 your patch includes sufficient directory information for the
4905 We prefer patches as plain text. MIME attachments are discouraged,
4906 and compressed attachments must not be used.
4908 * If one logical set of modifications affects or creates several
4909 files, all these changes shall be submitted in a SINGLE patch file.
4911 * Changesets that contain different, unrelated modifications shall be
4912 submitted as SEPARATE patches, one patch per changeset.
4917 * Before sending the patch, run the MAKEALL script on your patched
4918 source tree and make sure that no errors or warnings are reported
4919 for any of the boards.
4921 * Keep your modifications to the necessary minimum: A patch
4922 containing several unrelated changes or arbitrary reformats will be
4923 returned with a request to re-formatting / split it.
4925 * If you modify existing code, make sure that your new code does not
4926 add to the memory footprint of the code ;-) Small is beautiful!
4927 When adding new features, these should compile conditionally only
4928 (using #ifdef), and the resulting code with the new feature
4929 disabled must not need more memory than the old code without your
4932 * Remember that there is a size limit of 100 kB per message on the
4933 u-boot mailing list. Bigger patches will be moderated. If they are
4934 reasonable and not too big, they will be acknowledged. But patches
4935 bigger than the size limit should be avoided.