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.
423 - Linux Kernel Interface:
426 U-Boot stores all clock information in Hz
427 internally. For binary compatibility with older Linux
428 kernels (which expect the clocks passed in the
429 bd_info data to be in MHz) the environment variable
430 "clocks_in_mhz" can be defined so that U-Boot
431 converts clock data to MHZ before passing it to the
433 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
434 "clocks_in_mhz=1" is automatically included in the
437 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
439 When transferring memsize parameter to linux, some versions
440 expect it to be in bytes, others in MB.
441 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
445 New kernel versions are expecting firmware settings to be
446 passed using flattened device trees (based on open firmware
450 * New libfdt-based support
451 * Adds the "fdt" command
452 * The bootm command automatically updates the fdt
454 OF_CPU - The proper name of the cpus node (only required for
455 MPC512X and MPC5xxx based boards).
456 OF_SOC - The proper name of the soc node (only required for
457 MPC512X and MPC5xxx based boards).
458 OF_TBCLK - The timebase frequency.
459 OF_STDOUT_PATH - The path to the console device
461 boards with QUICC Engines require OF_QE to set UCC MAC
464 CONFIG_OF_BOARD_SETUP
466 Board code has addition modification that it wants to make
467 to the flat device tree before handing it off to the kernel
471 This define fills in the correct boot CPU in the boot
472 param header, the default value is zero if undefined.
476 U-Boot can detect if an IDE device is present or not.
477 If not, and this new config option is activated, U-Boot
478 removes the ATA node from the DTS before booting Linux,
479 so the Linux IDE driver does not probe the device and
480 crash. This is needed for buggy hardware (uc101) where
481 no pull down resistor is connected to the signal IDE5V_DD7.
483 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
485 This setting is mandatory for all boards that have only one
486 machine type and must be used to specify the machine type
487 number as it appears in the ARM machine registry
488 (see http://www.arm.linux.org.uk/developer/machines/).
489 Only boards that have multiple machine types supported
490 in a single configuration file and the machine type is
491 runtime discoverable, do not have to use this setting.
493 - vxWorks boot parameters:
495 bootvx constructs a valid bootline using the following
496 environments variables: bootfile, ipaddr, serverip, hostname.
497 It loads the vxWorks image pointed bootfile.
499 CONFIG_SYS_VXWORKS_BOOT_DEVICE - The vxworks device name
500 CONFIG_SYS_VXWORKS_MAC_PTR - Ethernet 6 byte MA -address
501 CONFIG_SYS_VXWORKS_SERVERNAME - Name of the server
502 CONFIG_SYS_VXWORKS_BOOT_ADDR - Address of boot parameters
504 CONFIG_SYS_VXWORKS_ADD_PARAMS
506 Add it at the end of the bootline. E.g "u=username pw=secret"
508 Note: If a "bootargs" environment is defined, it will overwride
509 the defaults discussed just above.
511 - Cache Configuration:
512 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
513 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
514 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
516 - Cache Configuration for ARM:
517 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
519 CONFIG_SYS_PL310_BASE - Physical base address of PL310
520 controller register space
525 Define this if you want support for Amba PrimeCell PL010 UARTs.
529 Define this if you want support for Amba PrimeCell PL011 UARTs.
533 If you have Amba PrimeCell PL011 UARTs, set this variable to
534 the clock speed of the UARTs.
538 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
539 define this to a list of base addresses for each (supported)
540 port. See e.g. include/configs/versatile.h
542 CONFIG_PL011_SERIAL_RLCR
544 Some vendor versions of PL011 serial ports (e.g. ST-Ericsson U8500)
545 have separate receive and transmit line control registers. Set
546 this variable to initialize the extra register.
548 CONFIG_PL011_SERIAL_FLUSH_ON_INIT
550 On some platforms (e.g. U8500) U-Boot is loaded by a second stage
551 boot loader that has already initialized the UART. Define this
552 variable to flush the UART at init time.
556 Depending on board, define exactly one serial port
557 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
558 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
559 console by defining CONFIG_8xx_CONS_NONE
561 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
562 port routines must be defined elsewhere
563 (i.e. serial_init(), serial_getc(), ...)
566 Enables console device for a color framebuffer. Needs following
567 defines (cf. smiLynxEM, i8042)
568 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
570 VIDEO_HW_RECTFILL graphic chip supports
573 VIDEO_HW_BITBLT graphic chip supports
574 bit-blit (cf. smiLynxEM)
575 VIDEO_VISIBLE_COLS visible pixel columns
577 VIDEO_VISIBLE_ROWS visible pixel rows
578 VIDEO_PIXEL_SIZE bytes per pixel
579 VIDEO_DATA_FORMAT graphic data format
580 (0-5, cf. cfb_console.c)
581 VIDEO_FB_ADRS framebuffer address
582 VIDEO_KBD_INIT_FCT keyboard int fct
583 (i.e. i8042_kbd_init())
584 VIDEO_TSTC_FCT test char fct
586 VIDEO_GETC_FCT get char fct
588 CONFIG_CONSOLE_CURSOR cursor drawing on/off
589 (requires blink timer
591 CONFIG_SYS_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
592 CONFIG_CONSOLE_TIME display time/date info in
594 (requires CONFIG_CMD_DATE)
595 CONFIG_VIDEO_LOGO display Linux logo in
597 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
598 linux_logo.h for logo.
599 Requires CONFIG_VIDEO_LOGO
600 CONFIG_CONSOLE_EXTRA_INFO
601 additional board info beside
604 When CONFIG_CFB_CONSOLE is defined, video console is
605 default i/o. Serial console can be forced with
606 environment 'console=serial'.
608 When CONFIG_SILENT_CONSOLE is defined, all console
609 messages (by U-Boot and Linux!) can be silenced with
610 the "silent" environment variable. See
611 doc/README.silent for more information.
614 CONFIG_BAUDRATE - in bps
615 Select one of the baudrates listed in
616 CONFIG_SYS_BAUDRATE_TABLE, see below.
617 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
619 - Console Rx buffer length
620 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
621 the maximum receive buffer length for the SMC.
622 This option is actual only for 82xx and 8xx possible.
623 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
624 must be defined, to setup the maximum idle timeout for
627 - Pre-Console Buffer:
628 Prior to the console being initialised (i.e. serial UART
629 initialised etc) all console output is silently discarded.
630 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
631 buffer any console messages prior to the console being
632 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
633 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
634 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
635 bytes are output before the console is initialised, the
636 earlier bytes are discarded.
638 'Sane' compilers will generate smaller code if
639 CONFIG_PRE_CON_BUF_SZ is a power of 2
641 - Pre-console putc():
642 Prior to the console being initialised, console output is
643 normally silently discarded. This can be annoying if a
644 panic() happens in this time.
646 If the CONFIG_PRE_CONSOLE_PUTC option is defined, then
647 U-Boot will call board_pre_console_putc() for each output
648 character in this case, This function should try to output
649 the character if possible, perhaps on all available UARTs
650 (it will need to do this directly, since the console code
651 is not functional yet). Note that if the panic happens
652 early enough, then it is possible that board_init_f()
653 (or even arch_cpu_init() on ARM) has not been called yet.
654 You should init all clocks, GPIOs, etc. that are needed
655 to get the character out. Baud rates will need to default
656 to something sensible.
658 - Safe printf() functions
659 Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
660 the printf() functions. These are defined in
661 include/vsprintf.h and include snprintf(), vsnprintf() and
662 so on. Code size increase is approximately 300-500 bytes.
663 If this option is not given then these functions will
664 silently discard their buffer size argument - this means
665 you are not getting any overflow checking in this case.
667 - Boot Delay: CONFIG_BOOTDELAY - in seconds
668 Delay before automatically booting the default image;
669 set to -1 to disable autoboot.
671 See doc/README.autoboot for these options that
672 work with CONFIG_BOOTDELAY. None are required.
673 CONFIG_BOOT_RETRY_TIME
674 CONFIG_BOOT_RETRY_MIN
675 CONFIG_AUTOBOOT_KEYED
676 CONFIG_AUTOBOOT_PROMPT
677 CONFIG_AUTOBOOT_DELAY_STR
678 CONFIG_AUTOBOOT_STOP_STR
679 CONFIG_AUTOBOOT_DELAY_STR2
680 CONFIG_AUTOBOOT_STOP_STR2
681 CONFIG_ZERO_BOOTDELAY_CHECK
682 CONFIG_RESET_TO_RETRY
686 Only needed when CONFIG_BOOTDELAY is enabled;
687 define a command string that is automatically executed
688 when no character is read on the console interface
689 within "Boot Delay" after reset.
692 This can be used to pass arguments to the bootm
693 command. The value of CONFIG_BOOTARGS goes into the
694 environment value "bootargs".
696 CONFIG_RAMBOOT and CONFIG_NFSBOOT
697 The value of these goes into the environment as
698 "ramboot" and "nfsboot" respectively, and can be used
699 as a convenience, when switching between booting from
705 When this option is #defined, the existence of the
706 environment variable "preboot" will be checked
707 immediately before starting the CONFIG_BOOTDELAY
708 countdown and/or running the auto-boot command resp.
709 entering interactive mode.
711 This feature is especially useful when "preboot" is
712 automatically generated or modified. For an example
713 see the LWMON board specific code: here "preboot" is
714 modified when the user holds down a certain
715 combination of keys on the (special) keyboard when
718 - Serial Download Echo Mode:
720 If defined to 1, all characters received during a
721 serial download (using the "loads" command) are
722 echoed back. This might be needed by some terminal
723 emulations (like "cu"), but may as well just take
724 time on others. This setting #define's the initial
725 value of the "loads_echo" environment variable.
727 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
729 Select one of the baudrates listed in
730 CONFIG_SYS_BAUDRATE_TABLE, see below.
733 Monitor commands can be included or excluded
734 from the build by using the #include files
735 "config_cmd_all.h" and #undef'ing unwanted
736 commands, or using "config_cmd_default.h"
737 and augmenting with additional #define's
740 The default command configuration includes all commands
741 except those marked below with a "*".
743 CONFIG_CMD_ASKENV * ask for env variable
744 CONFIG_CMD_BDI bdinfo
745 CONFIG_CMD_BEDBUG * Include BedBug Debugger
746 CONFIG_CMD_BMP * BMP support
747 CONFIG_CMD_BSP * Board specific commands
748 CONFIG_CMD_BOOTD bootd
749 CONFIG_CMD_CACHE * icache, dcache
750 CONFIG_CMD_CONSOLE coninfo
751 CONFIG_CMD_CRC32 * crc32
752 CONFIG_CMD_DATE * support for RTC, date/time...
753 CONFIG_CMD_DHCP * DHCP support
754 CONFIG_CMD_DIAG * Diagnostics
755 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
756 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
757 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
758 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
759 CONFIG_CMD_DTT * Digital Therm and Thermostat
760 CONFIG_CMD_ECHO echo arguments
761 CONFIG_CMD_EDITENV edit env variable
762 CONFIG_CMD_EEPROM * EEPROM read/write support
763 CONFIG_CMD_ELF * bootelf, bootvx
764 CONFIG_CMD_EXPORTENV * export the environment
765 CONFIG_CMD_SAVEENV saveenv
766 CONFIG_CMD_FDC * Floppy Disk Support
767 CONFIG_CMD_FAT * FAT partition support
768 CONFIG_CMD_FDOS * Dos diskette Support
769 CONFIG_CMD_FLASH flinfo, erase, protect
770 CONFIG_CMD_FPGA FPGA device initialization support
771 CONFIG_CMD_GO * the 'go' command (exec code)
772 CONFIG_CMD_GREPENV * search environment
773 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
774 CONFIG_CMD_I2C * I2C serial bus support
775 CONFIG_CMD_IDE * IDE harddisk support
776 CONFIG_CMD_IMI iminfo
777 CONFIG_CMD_IMLS List all found images
778 CONFIG_CMD_IMMAP * IMMR dump support
779 CONFIG_CMD_IMPORTENV * import an environment
780 CONFIG_CMD_IRQ * irqinfo
781 CONFIG_CMD_ITEST Integer/string test of 2 values
782 CONFIG_CMD_JFFS2 * JFFS2 Support
783 CONFIG_CMD_KGDB * kgdb
784 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
785 CONFIG_CMD_LOADB loadb
786 CONFIG_CMD_LOADS loads
787 CONFIG_CMD_MD5SUM print md5 message digest
788 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
789 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
791 CONFIG_CMD_MISC Misc functions like sleep etc
792 CONFIG_CMD_MMC * MMC memory mapped support
793 CONFIG_CMD_MII * MII utility commands
794 CONFIG_CMD_MTDPARTS * MTD partition support
795 CONFIG_CMD_NAND * NAND support
796 CONFIG_CMD_NET bootp, tftpboot, rarpboot
797 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
798 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
799 CONFIG_CMD_PCI * pciinfo
800 CONFIG_CMD_PCMCIA * PCMCIA support
801 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
803 CONFIG_CMD_PORTIO * Port I/O
804 CONFIG_CMD_REGINFO * Register dump
805 CONFIG_CMD_RUN run command in env variable
806 CONFIG_CMD_SAVES * save S record dump
807 CONFIG_CMD_SCSI * SCSI Support
808 CONFIG_CMD_SDRAM * print SDRAM configuration information
809 (requires CONFIG_CMD_I2C)
810 CONFIG_CMD_SETGETDCR Support for DCR Register access
812 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
813 CONFIG_CMD_SHA1SUM print sha1 memory digest
814 (requires CONFIG_CMD_MEMORY)
815 CONFIG_CMD_SOURCE "source" command Support
816 CONFIG_CMD_SPI * SPI serial bus support
817 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
818 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
819 CONFIG_CMD_TIME * run command and report execution time
820 CONFIG_CMD_USB * USB support
821 CONFIG_CMD_CDP * Cisco Discover Protocol support
822 CONFIG_CMD_FSL * Microblaze FSL support
825 EXAMPLE: If you want all functions except of network
826 support you can write:
828 #include "config_cmd_all.h"
829 #undef CONFIG_CMD_NET
832 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
834 Note: Don't enable the "icache" and "dcache" commands
835 (configuration option CONFIG_CMD_CACHE) unless you know
836 what you (and your U-Boot users) are doing. Data
837 cache cannot be enabled on systems like the 8xx or
838 8260 (where accesses to the IMMR region must be
839 uncached), and it cannot be disabled on all other
840 systems where we (mis-) use the data cache to hold an
841 initial stack and some data.
844 XXX - this list needs to get updated!
848 If this variable is defined, U-Boot will use a device tree
849 to configure its devices, instead of relying on statically
850 compiled #defines in the board file. This option is
851 experimental and only available on a few boards. The device
852 tree is available in the global data as gd->fdt_blob.
854 U-Boot needs to get its device tree from somewhere. This can
855 be done using one of the two options below:
858 If this variable is defined, U-Boot will embed a device tree
859 binary in its image. This device tree file should be in the
860 board directory and called <soc>-<board>.dts. The binary file
861 is then picked up in board_init_f() and made available through
862 the global data structure as gd->blob.
865 If this variable is defined, U-Boot will build a device tree
866 binary. It will be called u-boot.dtb. Architecture-specific
867 code will locate it at run-time. Generally this works by:
869 cat u-boot.bin u-boot.dtb >image.bin
871 and in fact, U-Boot does this for you, creating a file called
872 u-boot-dtb.bin which is useful in the common case. You can
873 still use the individual files if you need something more
878 If this variable is defined, it enables watchdog
879 support for the SoC. There must be support in the SoC
880 specific code for a watchdog. For the 8xx and 8260
881 CPUs, the SIU Watchdog feature is enabled in the SYPCR
882 register. When supported for a specific SoC is
883 available, then no further board specific code should
887 When using a watchdog circuitry external to the used
888 SoC, then define this variable and provide board
889 specific code for the "hw_watchdog_reset" function.
892 CONFIG_VERSION_VARIABLE
893 If this variable is defined, an environment variable
894 named "ver" is created by U-Boot showing the U-Boot
895 version as printed by the "version" command.
896 This variable is readonly.
900 When CONFIG_CMD_DATE is selected, the type of the RTC
901 has to be selected, too. Define exactly one of the
904 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
905 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
906 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
907 CONFIG_RTC_MC146818 - use MC146818 RTC
908 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
909 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
910 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
911 CONFIG_RTC_DS164x - use Dallas DS164x RTC
912 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
913 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
914 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
915 CONFIG_SYS_RV3029_TCR - enable trickle charger on
918 Note that if the RTC uses I2C, then the I2C interface
919 must also be configured. See I2C Support, below.
922 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
923 CONFIG_PCA953X_INFO - enable pca953x info command
925 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
926 chip-ngpio pairs that tell the PCA953X driver the number of
927 pins supported by a particular chip.
929 Note that if the GPIO device uses I2C, then the I2C interface
930 must also be configured. See I2C Support, below.
934 When CONFIG_TIMESTAMP is selected, the timestamp
935 (date and time) of an image is printed by image
936 commands like bootm or iminfo. This option is
937 automatically enabled when you select CONFIG_CMD_DATE .
940 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
941 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
943 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
944 CONFIG_CMD_SCSI) you must configure support for at
945 least one partition type as well.
948 CONFIG_IDE_RESET_ROUTINE - this is defined in several
949 board configurations files but used nowhere!
951 CONFIG_IDE_RESET - is this is defined, IDE Reset will
952 be performed by calling the function
953 ide_set_reset(int reset)
954 which has to be defined in a board specific file
959 Set this to enable ATAPI support.
964 Set this to enable support for disks larger than 137GB
965 Also look at CONFIG_SYS_64BIT_LBA.
966 Whithout these , LBA48 support uses 32bit variables and will 'only'
967 support disks up to 2.1TB.
969 CONFIG_SYS_64BIT_LBA:
970 When enabled, makes the IDE subsystem use 64bit sector addresses.
974 At the moment only there is only support for the
975 SYM53C8XX SCSI controller; define
976 CONFIG_SCSI_SYM53C8XX to enable it.
978 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
979 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
980 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
981 maximum numbers of LUNs, SCSI ID's and target
983 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
985 - NETWORK Support (PCI):
987 Support for Intel 8254x/8257x gigabit chips.
990 Utility code for direct access to the SPI bus on Intel 8257x.
991 This does not do anything useful unless you set at least one
992 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
994 CONFIG_E1000_SPI_GENERIC
995 Allow generic access to the SPI bus on the Intel 8257x, for
996 example with the "sspi" command.
999 Management command for E1000 devices. When used on devices
1000 with SPI support you can reprogram the EEPROM from U-Boot.
1002 CONFIG_E1000_FALLBACK_MAC
1003 default MAC for empty EEPROM after production.
1006 Support for Intel 82557/82559/82559ER chips.
1007 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1008 write routine for first time initialisation.
1011 Support for Digital 2114x chips.
1012 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1013 modem chip initialisation (KS8761/QS6611).
1016 Support for National dp83815 chips.
1019 Support for National dp8382[01] gigabit chips.
1021 - NETWORK Support (other):
1023 CONFIG_DRIVER_AT91EMAC
1024 Support for AT91RM9200 EMAC.
1027 Define this to use reduced MII inteface
1029 CONFIG_DRIVER_AT91EMAC_QUIET
1030 If this defined, the driver is quiet.
1031 The driver doen't show link status messages.
1033 CONFIG_CALXEDA_XGMAC
1034 Support for the Calxeda XGMAC device
1036 CONFIG_DRIVER_LAN91C96
1037 Support for SMSC's LAN91C96 chips.
1039 CONFIG_LAN91C96_BASE
1040 Define this to hold the physical address
1041 of the LAN91C96's I/O space
1043 CONFIG_LAN91C96_USE_32_BIT
1044 Define this to enable 32 bit addressing
1046 CONFIG_DRIVER_SMC91111
1047 Support for SMSC's LAN91C111 chip
1049 CONFIG_SMC91111_BASE
1050 Define this to hold the physical address
1051 of the device (I/O space)
1053 CONFIG_SMC_USE_32_BIT
1054 Define this if data bus is 32 bits
1056 CONFIG_SMC_USE_IOFUNCS
1057 Define this to use i/o functions instead of macros
1058 (some hardware wont work with macros)
1060 CONFIG_DRIVER_TI_EMAC
1061 Support for davinci emac
1063 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1064 Define this if you have more then 3 PHYs.
1067 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1069 CONFIG_FTGMAC100_EGIGA
1070 Define this to use GE link update with gigabit PHY.
1071 Define this if FTGMAC100 is connected to gigabit PHY.
1072 If your system has 10/100 PHY only, it might not occur
1073 wrong behavior. Because PHY usually return timeout or
1074 useless data when polling gigabit status and gigabit
1075 control registers. This behavior won't affect the
1076 correctnessof 10/100 link speed update.
1079 Support for SMSC's LAN911x and LAN921x chips
1082 Define this to hold the physical address
1083 of the device (I/O space)
1085 CONFIG_SMC911X_32_BIT
1086 Define this if data bus is 32 bits
1088 CONFIG_SMC911X_16_BIT
1089 Define this if data bus is 16 bits. If your processor
1090 automatically converts one 32 bit word to two 16 bit
1091 words you may also try CONFIG_SMC911X_32_BIT.
1094 Support for Renesas on-chip Ethernet controller
1096 CONFIG_SH_ETHER_USE_PORT
1097 Define the number of ports to be used
1099 CONFIG_SH_ETHER_PHY_ADDR
1100 Define the ETH PHY's address
1102 CONFIG_SH_ETHER_CACHE_WRITEBACK
1103 If this option is set, the driver enables cache flush.
1106 CONFIG_GENERIC_LPC_TPM
1107 Support for generic parallel port TPM devices. Only one device
1108 per system is supported at this time.
1110 CONFIG_TPM_TIS_BASE_ADDRESS
1111 Base address where the generic TPM device is mapped
1112 to. Contemporary x86 systems usually map it at
1116 At the moment only the UHCI host controller is
1117 supported (PIP405, MIP405, MPC5200); define
1118 CONFIG_USB_UHCI to enable it.
1119 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1120 and define CONFIG_USB_STORAGE to enable the USB
1123 Supported are USB Keyboards and USB Floppy drives
1125 MPC5200 USB requires additional defines:
1127 for 528 MHz Clock: 0x0001bbbb
1131 for differential drivers: 0x00001000
1132 for single ended drivers: 0x00005000
1133 for differential drivers on PSC3: 0x00000100
1134 for single ended drivers on PSC3: 0x00004100
1135 CONFIG_SYS_USB_EVENT_POLL
1136 May be defined to allow interrupt polling
1137 instead of using asynchronous interrupts
1140 Define the below if you wish to use the USB console.
1141 Once firmware is rebuilt from a serial console issue the
1142 command "setenv stdin usbtty; setenv stdout usbtty" and
1143 attach your USB cable. The Unix command "dmesg" should print
1144 it has found a new device. The environment variable usbtty
1145 can be set to gserial or cdc_acm to enable your device to
1146 appear to a USB host as a Linux gserial device or a
1147 Common Device Class Abstract Control Model serial device.
1148 If you select usbtty = gserial you should be able to enumerate
1150 # modprobe usbserial vendor=0xVendorID product=0xProductID
1151 else if using cdc_acm, simply setting the environment
1152 variable usbtty to be cdc_acm should suffice. The following
1153 might be defined in YourBoardName.h
1156 Define this to build a UDC device
1159 Define this to have a tty type of device available to
1160 talk to the UDC device
1162 CONFIG_SYS_CONSOLE_IS_IN_ENV
1163 Define this if you want stdin, stdout &/or stderr to
1167 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1168 Derive USB clock from external clock "blah"
1169 - CONFIG_SYS_USB_EXTC_CLK 0x02
1171 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1172 Derive USB clock from brgclk
1173 - CONFIG_SYS_USB_BRG_CLK 0x04
1175 If you have a USB-IF assigned VendorID then you may wish to
1176 define your own vendor specific values either in BoardName.h
1177 or directly in usbd_vendor_info.h. If you don't define
1178 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1179 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1180 should pretend to be a Linux device to it's target host.
1182 CONFIG_USBD_MANUFACTURER
1183 Define this string as the name of your company for
1184 - CONFIG_USBD_MANUFACTURER "my company"
1186 CONFIG_USBD_PRODUCT_NAME
1187 Define this string as the name of your product
1188 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1190 CONFIG_USBD_VENDORID
1191 Define this as your assigned Vendor ID from the USB
1192 Implementors Forum. This *must* be a genuine Vendor ID
1193 to avoid polluting the USB namespace.
1194 - CONFIG_USBD_VENDORID 0xFFFF
1196 CONFIG_USBD_PRODUCTID
1197 Define this as the unique Product ID
1199 - CONFIG_USBD_PRODUCTID 0xFFFF
1201 - ULPI Layer Support:
1202 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1203 the generic ULPI layer. The generic layer accesses the ULPI PHY
1204 via the platform viewport, so you need both the genric layer and
1205 the viewport enabled. Currently only Chipidea/ARC based
1206 viewport is supported.
1207 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1208 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1211 The MMC controller on the Intel PXA is supported. To
1212 enable this define CONFIG_MMC. The MMC can be
1213 accessed from the boot prompt by mapping the device
1214 to physical memory similar to flash. Command line is
1215 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1216 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1219 Support for Renesas on-chip MMCIF controller
1221 CONFIG_SH_MMCIF_ADDR
1222 Define the base address of MMCIF registers
1225 Define the clock frequency for MMCIF
1227 - Journaling Flash filesystem support:
1228 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1229 CONFIG_JFFS2_NAND_DEV
1230 Define these for a default partition on a NAND device
1232 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1233 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1234 Define these for a default partition on a NOR device
1236 CONFIG_SYS_JFFS_CUSTOM_PART
1237 Define this to create an own partition. You have to provide a
1238 function struct part_info* jffs2_part_info(int part_num)
1240 If you define only one JFFS2 partition you may also want to
1241 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1242 to disable the command chpart. This is the default when you
1243 have not defined a custom partition
1245 - FAT(File Allocation Table) filesystem write function support:
1247 Support for saving memory data as a file
1248 in FAT formatted partition
1253 Define this to enable standard (PC-Style) keyboard
1257 Standard PC keyboard driver with US (is default) and
1258 GERMAN key layout (switch via environment 'keymap=de') support.
1259 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1260 for cfb_console. Supports cursor blinking.
1265 Define this to enable video support (for output to
1268 CONFIG_VIDEO_CT69000
1270 Enable Chips & Technologies 69000 Video chip
1272 CONFIG_VIDEO_SMI_LYNXEM
1273 Enable Silicon Motion SMI 712/710/810 Video chip. The
1274 video output is selected via environment 'videoout'
1275 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1278 For the CT69000 and SMI_LYNXEM drivers, videomode is
1279 selected via environment 'videomode'. Two different ways
1281 - "videomode=num" 'num' is a standard LiLo mode numbers.
1282 Following standard modes are supported (* is default):
1284 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1285 -------------+---------------------------------------------
1286 8 bits | 0x301* 0x303 0x305 0x161 0x307
1287 15 bits | 0x310 0x313 0x316 0x162 0x319
1288 16 bits | 0x311 0x314 0x317 0x163 0x31A
1289 24 bits | 0x312 0x315 0x318 ? 0x31B
1290 -------------+---------------------------------------------
1291 (i.e. setenv videomode 317; saveenv; reset;)
1293 - "videomode=bootargs" all the video parameters are parsed
1294 from the bootargs. (See drivers/video/videomodes.c)
1297 CONFIG_VIDEO_SED13806
1298 Enable Epson SED13806 driver. This driver supports 8bpp
1299 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1300 or CONFIG_VIDEO_SED13806_16BPP
1303 Enable the Freescale DIU video driver. Reference boards for
1304 SOCs that have a DIU should define this macro to enable DIU
1305 support, and should also define these other macros:
1311 CONFIG_VIDEO_SW_CURSOR
1312 CONFIG_VGA_AS_SINGLE_DEVICE
1314 CONFIG_VIDEO_BMP_LOGO
1316 The DIU driver will look for the 'video-mode' environment
1317 variable, and if defined, enable the DIU as a console during
1318 boot. See the documentation file README.video for a
1319 description of this variable.
1324 Define this to enable a custom keyboard support.
1325 This simply calls drv_keyboard_init() which must be
1326 defined in your board-specific files.
1327 The only board using this so far is RBC823.
1329 - LCD Support: CONFIG_LCD
1331 Define this to enable LCD support (for output to LCD
1332 display); also select one of the supported displays
1333 by defining one of these:
1337 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1339 CONFIG_NEC_NL6448AC33:
1341 NEC NL6448AC33-18. Active, color, single scan.
1343 CONFIG_NEC_NL6448BC20
1345 NEC NL6448BC20-08. 6.5", 640x480.
1346 Active, color, single scan.
1348 CONFIG_NEC_NL6448BC33_54
1350 NEC NL6448BC33-54. 10.4", 640x480.
1351 Active, color, single scan.
1355 Sharp 320x240. Active, color, single scan.
1356 It isn't 16x9, and I am not sure what it is.
1358 CONFIG_SHARP_LQ64D341
1360 Sharp LQ64D341 display, 640x480.
1361 Active, color, single scan.
1365 HLD1045 display, 640x480.
1366 Active, color, single scan.
1370 Optrex CBL50840-2 NF-FW 99 22 M5
1372 Hitachi LMG6912RPFC-00T
1376 320x240. Black & white.
1378 Normally display is black on white background; define
1379 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1381 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1383 If this option is set, the environment is checked for
1384 a variable "splashimage". If found, the usual display
1385 of logo, copyright and system information on the LCD
1386 is suppressed and the BMP image at the address
1387 specified in "splashimage" is loaded instead. The
1388 console is redirected to the "nulldev", too. This
1389 allows for a "silent" boot where a splash screen is
1390 loaded very quickly after power-on.
1392 CONFIG_SPLASH_SCREEN_ALIGN
1394 If this option is set the splash image can be freely positioned
1395 on the screen. Environment variable "splashpos" specifies the
1396 position as "x,y". If a positive number is given it is used as
1397 number of pixel from left/top. If a negative number is given it
1398 is used as number of pixel from right/bottom. You can also
1399 specify 'm' for centering the image.
1402 setenv splashpos m,m
1403 => image at center of screen
1405 setenv splashpos 30,20
1406 => image at x = 30 and y = 20
1408 setenv splashpos -10,m
1409 => vertically centered image
1410 at x = dspWidth - bmpWidth - 9
1412 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1414 If this option is set, additionally to standard BMP
1415 images, gzipped BMP images can be displayed via the
1416 splashscreen support or the bmp command.
1418 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1420 If this option is set, 8-bit RLE compressed BMP images
1421 can be displayed via the splashscreen support or the
1424 - Compression support:
1427 If this option is set, support for bzip2 compressed
1428 images is included. If not, only uncompressed and gzip
1429 compressed images are supported.
1431 NOTE: the bzip2 algorithm requires a lot of RAM, so
1432 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1437 If this option is set, support for lzma compressed
1440 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1441 requires an amount of dynamic memory that is given by the
1444 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1446 Where lc and lp stand for, respectively, Literal context bits
1447 and Literal pos bits.
1449 This value is upper-bounded by 14MB in the worst case. Anyway,
1450 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1451 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1452 a very small buffer.
1454 Use the lzmainfo tool to determinate the lc and lp values and
1455 then calculate the amount of needed dynamic memory (ensuring
1456 the appropriate CONFIG_SYS_MALLOC_LEN value).
1461 The address of PHY on MII bus.
1463 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1465 The clock frequency of the MII bus
1469 If this option is set, support for speed/duplex
1470 detection of gigabit PHY is included.
1472 CONFIG_PHY_RESET_DELAY
1474 Some PHY like Intel LXT971A need extra delay after
1475 reset before any MII register access is possible.
1476 For such PHY, set this option to the usec delay
1477 required. (minimum 300usec for LXT971A)
1479 CONFIG_PHY_CMD_DELAY (ppc4xx)
1481 Some PHY like Intel LXT971A need extra delay after
1482 command issued before MII status register can be read
1492 Define a default value for Ethernet address to use
1493 for the respective Ethernet interface, in case this
1494 is not determined automatically.
1499 Define a default value for the IP address to use for
1500 the default Ethernet interface, in case this is not
1501 determined through e.g. bootp.
1502 (Environment variable "ipaddr")
1504 - Server IP address:
1507 Defines a default value for the IP address of a TFTP
1508 server to contact when using the "tftboot" command.
1509 (Environment variable "serverip")
1511 CONFIG_KEEP_SERVERADDR
1513 Keeps the server's MAC address, in the env 'serveraddr'
1514 for passing to bootargs (like Linux's netconsole option)
1516 - Gateway IP address:
1519 Defines a default value for the IP address of the
1520 default router where packets to other networks are
1522 (Environment variable "gatewayip")
1527 Defines a default value for the subnet mask (or
1528 routing prefix) which is used to determine if an IP
1529 address belongs to the local subnet or needs to be
1530 forwarded through a router.
1531 (Environment variable "netmask")
1533 - Multicast TFTP Mode:
1536 Defines whether you want to support multicast TFTP as per
1537 rfc-2090; for example to work with atftp. Lets lots of targets
1538 tftp down the same boot image concurrently. Note: the Ethernet
1539 driver in use must provide a function: mcast() to join/leave a
1542 - BOOTP Recovery Mode:
1543 CONFIG_BOOTP_RANDOM_DELAY
1545 If you have many targets in a network that try to
1546 boot using BOOTP, you may want to avoid that all
1547 systems send out BOOTP requests at precisely the same
1548 moment (which would happen for instance at recovery
1549 from a power failure, when all systems will try to
1550 boot, thus flooding the BOOTP server. Defining
1551 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1552 inserted before sending out BOOTP requests. The
1553 following delays are inserted then:
1555 1st BOOTP request: delay 0 ... 1 sec
1556 2nd BOOTP request: delay 0 ... 2 sec
1557 3rd BOOTP request: delay 0 ... 4 sec
1559 BOOTP requests: delay 0 ... 8 sec
1561 - DHCP Advanced Options:
1562 You can fine tune the DHCP functionality by defining
1563 CONFIG_BOOTP_* symbols:
1565 CONFIG_BOOTP_SUBNETMASK
1566 CONFIG_BOOTP_GATEWAY
1567 CONFIG_BOOTP_HOSTNAME
1568 CONFIG_BOOTP_NISDOMAIN
1569 CONFIG_BOOTP_BOOTPATH
1570 CONFIG_BOOTP_BOOTFILESIZE
1573 CONFIG_BOOTP_SEND_HOSTNAME
1574 CONFIG_BOOTP_NTPSERVER
1575 CONFIG_BOOTP_TIMEOFFSET
1576 CONFIG_BOOTP_VENDOREX
1578 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1579 environment variable, not the BOOTP server.
1581 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1582 serverip from a DHCP server, it is possible that more
1583 than one DNS serverip is offered to the client.
1584 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1585 serverip will be stored in the additional environment
1586 variable "dnsip2". The first DNS serverip is always
1587 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1590 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1591 to do a dynamic update of a DNS server. To do this, they
1592 need the hostname of the DHCP requester.
1593 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1594 of the "hostname" environment variable is passed as
1595 option 12 to the DHCP server.
1597 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1599 A 32bit value in microseconds for a delay between
1600 receiving a "DHCP Offer" and sending the "DHCP Request".
1601 This fixes a problem with certain DHCP servers that don't
1602 respond 100% of the time to a "DHCP request". E.g. On an
1603 AT91RM9200 processor running at 180MHz, this delay needed
1604 to be *at least* 15,000 usec before a Windows Server 2003
1605 DHCP server would reply 100% of the time. I recommend at
1606 least 50,000 usec to be safe. The alternative is to hope
1607 that one of the retries will be successful but note that
1608 the DHCP timeout and retry process takes a longer than
1612 CONFIG_CDP_DEVICE_ID
1614 The device id used in CDP trigger frames.
1616 CONFIG_CDP_DEVICE_ID_PREFIX
1618 A two character string which is prefixed to the MAC address
1623 A printf format string which contains the ascii name of
1624 the port. Normally is set to "eth%d" which sets
1625 eth0 for the first Ethernet, eth1 for the second etc.
1627 CONFIG_CDP_CAPABILITIES
1629 A 32bit integer which indicates the device capabilities;
1630 0x00000010 for a normal host which does not forwards.
1634 An ascii string containing the version of the software.
1638 An ascii string containing the name of the platform.
1642 A 32bit integer sent on the trigger.
1644 CONFIG_CDP_POWER_CONSUMPTION
1646 A 16bit integer containing the power consumption of the
1647 device in .1 of milliwatts.
1649 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1651 A byte containing the id of the VLAN.
1653 - Status LED: CONFIG_STATUS_LED
1655 Several configurations allow to display the current
1656 status using a LED. For instance, the LED will blink
1657 fast while running U-Boot code, stop blinking as
1658 soon as a reply to a BOOTP request was received, and
1659 start blinking slow once the Linux kernel is running
1660 (supported by a status LED driver in the Linux
1661 kernel). Defining CONFIG_STATUS_LED enables this
1664 - CAN Support: CONFIG_CAN_DRIVER
1666 Defining CONFIG_CAN_DRIVER enables CAN driver support
1667 on those systems that support this (optional)
1668 feature, like the TQM8xxL modules.
1670 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1672 These enable I2C serial bus commands. Defining either of
1673 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1674 include the appropriate I2C driver for the selected CPU.
1676 This will allow you to use i2c commands at the u-boot
1677 command line (as long as you set CONFIG_CMD_I2C in
1678 CONFIG_COMMANDS) and communicate with i2c based realtime
1679 clock chips. See common/cmd_i2c.c for a description of the
1680 command line interface.
1682 CONFIG_HARD_I2C selects a hardware I2C controller.
1684 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1685 bit-banging) driver instead of CPM or similar hardware
1688 There are several other quantities that must also be
1689 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1691 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1692 to be the frequency (in Hz) at which you wish your i2c bus
1693 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1694 the CPU's i2c node address).
1696 Now, the u-boot i2c code for the mpc8xx
1697 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1698 and so its address should therefore be cleared to 0 (See,
1699 eg, MPC823e User's Manual p.16-473). So, set
1700 CONFIG_SYS_I2C_SLAVE to 0.
1702 CONFIG_SYS_I2C_INIT_MPC5XXX
1704 When a board is reset during an i2c bus transfer
1705 chips might think that the current transfer is still
1706 in progress. Reset the slave devices by sending start
1707 commands until the slave device responds.
1709 That's all that's required for CONFIG_HARD_I2C.
1711 If you use the software i2c interface (CONFIG_SOFT_I2C)
1712 then the following macros need to be defined (examples are
1713 from include/configs/lwmon.h):
1717 (Optional). Any commands necessary to enable the I2C
1718 controller or configure ports.
1720 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1724 (Only for MPC8260 CPU). The I/O port to use (the code
1725 assumes both bits are on the same port). Valid values
1726 are 0..3 for ports A..D.
1730 The code necessary to make the I2C data line active
1731 (driven). If the data line is open collector, this
1734 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1738 The code necessary to make the I2C data line tri-stated
1739 (inactive). If the data line is open collector, this
1742 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1746 Code that returns TRUE if the I2C data line is high,
1749 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1753 If <bit> is TRUE, sets the I2C data line high. If it
1754 is FALSE, it clears it (low).
1756 eg: #define I2C_SDA(bit) \
1757 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1758 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1762 If <bit> is TRUE, sets the I2C clock line high. If it
1763 is FALSE, it clears it (low).
1765 eg: #define I2C_SCL(bit) \
1766 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1767 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1771 This delay is invoked four times per clock cycle so this
1772 controls the rate of data transfer. The data rate thus
1773 is 1 / (I2C_DELAY * 4). Often defined to be something
1776 #define I2C_DELAY udelay(2)
1778 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1780 If your arch supports the generic GPIO framework (asm/gpio.h),
1781 then you may alternatively define the two GPIOs that are to be
1782 used as SCL / SDA. Any of the previous I2C_xxx macros will
1783 have GPIO-based defaults assigned to them as appropriate.
1785 You should define these to the GPIO value as given directly to
1786 the generic GPIO functions.
1788 CONFIG_SYS_I2C_INIT_BOARD
1790 When a board is reset during an i2c bus transfer
1791 chips might think that the current transfer is still
1792 in progress. On some boards it is possible to access
1793 the i2c SCLK line directly, either by using the
1794 processor pin as a GPIO or by having a second pin
1795 connected to the bus. If this option is defined a
1796 custom i2c_init_board() routine in boards/xxx/board.c
1797 is run early in the boot sequence.
1799 CONFIG_SYS_I2C_BOARD_LATE_INIT
1801 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1802 defined a custom i2c_board_late_init() routine in
1803 boards/xxx/board.c is run AFTER the operations in i2c_init()
1804 is completed. This callpoint can be used to unreset i2c bus
1805 using CPU i2c controller register accesses for CPUs whose i2c
1806 controller provide such a method. It is called at the end of
1807 i2c_init() to allow i2c_init operations to setup the i2c bus
1808 controller on the CPU (e.g. setting bus speed & slave address).
1810 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1812 This option enables configuration of bi_iic_fast[] flags
1813 in u-boot bd_info structure based on u-boot environment
1814 variable "i2cfast". (see also i2cfast)
1816 CONFIG_I2C_MULTI_BUS
1818 This option allows the use of multiple I2C buses, each of which
1819 must have a controller. At any point in time, only one bus is
1820 active. To switch to a different bus, use the 'i2c dev' command.
1821 Note that bus numbering is zero-based.
1823 CONFIG_SYS_I2C_NOPROBES
1825 This option specifies a list of I2C devices that will be skipped
1826 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1827 is set, specify a list of bus-device pairs. Otherwise, specify
1828 a 1D array of device addresses
1831 #undef CONFIG_I2C_MULTI_BUS
1832 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1834 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1836 #define CONFIG_I2C_MULTI_BUS
1837 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1839 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1841 CONFIG_SYS_SPD_BUS_NUM
1843 If defined, then this indicates the I2C bus number for DDR SPD.
1844 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1846 CONFIG_SYS_RTC_BUS_NUM
1848 If defined, then this indicates the I2C bus number for the RTC.
1849 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1851 CONFIG_SYS_DTT_BUS_NUM
1853 If defined, then this indicates the I2C bus number for the DTT.
1854 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1856 CONFIG_SYS_I2C_DTT_ADDR:
1858 If defined, specifies the I2C address of the DTT device.
1859 If not defined, then U-Boot uses predefined value for
1860 specified DTT device.
1864 Define this option if you want to use Freescale's I2C driver in
1865 drivers/i2c/fsl_i2c.c.
1869 Define this option if you have I2C devices reached over 1 .. n
1870 I2C Muxes like the pca9544a. This option addes a new I2C
1871 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1872 new I2C Bus to the existing I2C Busses. If you select the
1873 new Bus with "i2c dev", u-bbot sends first the commandos for
1874 the muxes to activate this new "bus".
1876 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1880 Adding a new I2C Bus reached over 2 pca9544a muxes
1881 The First mux with address 70 and channel 6
1882 The Second mux with address 71 and channel 4
1884 => i2c bus pca9544a:70:6:pca9544a:71:4
1886 Use the "i2c bus" command without parameter, to get a list
1887 of I2C Busses with muxes:
1890 Busses reached over muxes:
1892 reached over Mux(es):
1895 reached over Mux(es):
1900 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1901 u-boot first sends the command to the mux@70 to enable
1902 channel 6, and then the command to the mux@71 to enable
1905 After that, you can use the "normal" i2c commands as
1906 usual to communicate with your I2C devices behind
1909 This option is actually implemented for the bitbanging
1910 algorithm in common/soft_i2c.c and for the Hardware I2C
1911 Bus on the MPC8260. But it should be not so difficult
1912 to add this option to other architectures.
1914 CONFIG_SOFT_I2C_READ_REPEATED_START
1916 defining this will force the i2c_read() function in
1917 the soft_i2c driver to perform an I2C repeated start
1918 between writing the address pointer and reading the
1919 data. If this define is omitted the default behaviour
1920 of doing a stop-start sequence will be used. Most I2C
1921 devices can use either method, but some require one or
1924 - SPI Support: CONFIG_SPI
1926 Enables SPI driver (so far only tested with
1927 SPI EEPROM, also an instance works with Crystal A/D and
1928 D/As on the SACSng board)
1932 Enables the driver for SPI controller on SuperH. Currently
1933 only SH7757 is supported.
1937 Enables extended (16-bit) SPI EEPROM addressing.
1938 (symmetrical to CONFIG_I2C_X)
1942 Enables a software (bit-bang) SPI driver rather than
1943 using hardware support. This is a general purpose
1944 driver that only requires three general I/O port pins
1945 (two outputs, one input) to function. If this is
1946 defined, the board configuration must define several
1947 SPI configuration items (port pins to use, etc). For
1948 an example, see include/configs/sacsng.h.
1952 Enables a hardware SPI driver for general-purpose reads
1953 and writes. As with CONFIG_SOFT_SPI, the board configuration
1954 must define a list of chip-select function pointers.
1955 Currently supported on some MPC8xxx processors. For an
1956 example, see include/configs/mpc8349emds.h.
1960 Enables the driver for the SPI controllers on i.MX and MXC
1961 SoCs. Currently i.MX31/35/51 are supported.
1963 - FPGA Support: CONFIG_FPGA
1965 Enables FPGA subsystem.
1967 CONFIG_FPGA_<vendor>
1969 Enables support for specific chip vendors.
1972 CONFIG_FPGA_<family>
1974 Enables support for FPGA family.
1975 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1979 Specify the number of FPGA devices to support.
1981 CONFIG_SYS_FPGA_PROG_FEEDBACK
1983 Enable printing of hash marks during FPGA configuration.
1985 CONFIG_SYS_FPGA_CHECK_BUSY
1987 Enable checks on FPGA configuration interface busy
1988 status by the configuration function. This option
1989 will require a board or device specific function to
1994 If defined, a function that provides delays in the FPGA
1995 configuration driver.
1997 CONFIG_SYS_FPGA_CHECK_CTRLC
1998 Allow Control-C to interrupt FPGA configuration
2000 CONFIG_SYS_FPGA_CHECK_ERROR
2002 Check for configuration errors during FPGA bitfile
2003 loading. For example, abort during Virtex II
2004 configuration if the INIT_B line goes low (which
2005 indicated a CRC error).
2007 CONFIG_SYS_FPGA_WAIT_INIT
2009 Maximum time to wait for the INIT_B line to deassert
2010 after PROB_B has been deasserted during a Virtex II
2011 FPGA configuration sequence. The default time is 500
2014 CONFIG_SYS_FPGA_WAIT_BUSY
2016 Maximum time to wait for BUSY to deassert during
2017 Virtex II FPGA configuration. The default is 5 ms.
2019 CONFIG_SYS_FPGA_WAIT_CONFIG
2021 Time to wait after FPGA configuration. The default is
2024 - Configuration Management:
2027 If defined, this string will be added to the U-Boot
2028 version information (U_BOOT_VERSION)
2030 - Vendor Parameter Protection:
2032 U-Boot considers the values of the environment
2033 variables "serial#" (Board Serial Number) and
2034 "ethaddr" (Ethernet Address) to be parameters that
2035 are set once by the board vendor / manufacturer, and
2036 protects these variables from casual modification by
2037 the user. Once set, these variables are read-only,
2038 and write or delete attempts are rejected. You can
2039 change this behaviour:
2041 If CONFIG_ENV_OVERWRITE is #defined in your config
2042 file, the write protection for vendor parameters is
2043 completely disabled. Anybody can change or delete
2046 Alternatively, if you #define _both_ CONFIG_ETHADDR
2047 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2048 Ethernet address is installed in the environment,
2049 which can be changed exactly ONCE by the user. [The
2050 serial# is unaffected by this, i. e. it remains
2056 Define this variable to enable the reservation of
2057 "protected RAM", i. e. RAM which is not overwritten
2058 by U-Boot. Define CONFIG_PRAM to hold the number of
2059 kB you want to reserve for pRAM. You can overwrite
2060 this default value by defining an environment
2061 variable "pram" to the number of kB you want to
2062 reserve. Note that the board info structure will
2063 still show the full amount of RAM. If pRAM is
2064 reserved, a new environment variable "mem" will
2065 automatically be defined to hold the amount of
2066 remaining RAM in a form that can be passed as boot
2067 argument to Linux, for instance like that:
2069 setenv bootargs ... mem=\${mem}
2072 This way you can tell Linux not to use this memory,
2073 either, which results in a memory region that will
2074 not be affected by reboots.
2076 *WARNING* If your board configuration uses automatic
2077 detection of the RAM size, you must make sure that
2078 this memory test is non-destructive. So far, the
2079 following board configurations are known to be
2082 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2083 HERMES, IP860, RPXlite, LWMON, LANTEC,
2089 Define this variable to stop the system in case of a
2090 fatal error, so that you have to reset it manually.
2091 This is probably NOT a good idea for an embedded
2092 system where you want the system to reboot
2093 automatically as fast as possible, but it may be
2094 useful during development since you can try to debug
2095 the conditions that lead to the situation.
2097 CONFIG_NET_RETRY_COUNT
2099 This variable defines the number of retries for
2100 network operations like ARP, RARP, TFTP, or BOOTP
2101 before giving up the operation. If not defined, a
2102 default value of 5 is used.
2106 Timeout waiting for an ARP reply in milliseconds.
2108 - Command Interpreter:
2109 CONFIG_AUTO_COMPLETE
2111 Enable auto completion of commands using TAB.
2113 Note that this feature has NOT been implemented yet
2114 for the "hush" shell.
2117 CONFIG_SYS_HUSH_PARSER
2119 Define this variable to enable the "hush" shell (from
2120 Busybox) as command line interpreter, thus enabling
2121 powerful command line syntax like
2122 if...then...else...fi conditionals or `&&' and '||'
2123 constructs ("shell scripts").
2125 If undefined, you get the old, much simpler behaviour
2126 with a somewhat smaller memory footprint.
2129 CONFIG_SYS_PROMPT_HUSH_PS2
2131 This defines the secondary prompt string, which is
2132 printed when the command interpreter needs more input
2133 to complete a command. Usually "> ".
2137 In the current implementation, the local variables
2138 space and global environment variables space are
2139 separated. Local variables are those you define by
2140 simply typing `name=value'. To access a local
2141 variable later on, you have write `$name' or
2142 `${name}'; to execute the contents of a variable
2143 directly type `$name' at the command prompt.
2145 Global environment variables are those you use
2146 setenv/printenv to work with. To run a command stored
2147 in such a variable, you need to use the run command,
2148 and you must not use the '$' sign to access them.
2150 To store commands and special characters in a
2151 variable, please use double quotation marks
2152 surrounding the whole text of the variable, instead
2153 of the backslashes before semicolons and special
2156 - Commandline Editing and History:
2157 CONFIG_CMDLINE_EDITING
2159 Enable editing and History functions for interactive
2160 commandline input operations
2162 - Default Environment:
2163 CONFIG_EXTRA_ENV_SETTINGS
2165 Define this to contain any number of null terminated
2166 strings (variable = value pairs) that will be part of
2167 the default environment compiled into the boot image.
2169 For example, place something like this in your
2170 board's config file:
2172 #define CONFIG_EXTRA_ENV_SETTINGS \
2176 Warning: This method is based on knowledge about the
2177 internal format how the environment is stored by the
2178 U-Boot code. This is NOT an official, exported
2179 interface! Although it is unlikely that this format
2180 will change soon, there is no guarantee either.
2181 You better know what you are doing here.
2183 Note: overly (ab)use of the default environment is
2184 discouraged. Make sure to check other ways to preset
2185 the environment like the "source" command or the
2188 - DataFlash Support:
2189 CONFIG_HAS_DATAFLASH
2191 Defining this option enables DataFlash features and
2192 allows to read/write in Dataflash via the standard
2195 - Serial Flash support
2198 Defining this option enables SPI flash commands
2199 'sf probe/read/write/erase/update'.
2201 Usage requires an initial 'probe' to define the serial
2202 flash parameters, followed by read/write/erase/update
2205 The following defaults may be provided by the platform
2206 to handle the common case when only a single serial
2207 flash is present on the system.
2209 CONFIG_SF_DEFAULT_BUS Bus identifier
2210 CONFIG_SF_DEFAULT_CS Chip-select
2211 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2212 CONFIG_SF_DEFAULT_SPEED in Hz
2214 - SystemACE Support:
2217 Adding this option adds support for Xilinx SystemACE
2218 chips attached via some sort of local bus. The address
2219 of the chip must also be defined in the
2220 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2222 #define CONFIG_SYSTEMACE
2223 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2225 When SystemACE support is added, the "ace" device type
2226 becomes available to the fat commands, i.e. fatls.
2228 - TFTP Fixed UDP Port:
2231 If this is defined, the environment variable tftpsrcp
2232 is used to supply the TFTP UDP source port value.
2233 If tftpsrcp isn't defined, the normal pseudo-random port
2234 number generator is used.
2236 Also, the environment variable tftpdstp is used to supply
2237 the TFTP UDP destination port value. If tftpdstp isn't
2238 defined, the normal port 69 is used.
2240 The purpose for tftpsrcp is to allow a TFTP server to
2241 blindly start the TFTP transfer using the pre-configured
2242 target IP address and UDP port. This has the effect of
2243 "punching through" the (Windows XP) firewall, allowing
2244 the remainder of the TFTP transfer to proceed normally.
2245 A better solution is to properly configure the firewall,
2246 but sometimes that is not allowed.
2248 - Show boot progress:
2249 CONFIG_SHOW_BOOT_PROGRESS
2251 Defining this option allows to add some board-
2252 specific code (calling a user-provided function
2253 "show_boot_progress(int)") that enables you to show
2254 the system's boot progress on some display (for
2255 example, some LED's) on your board. At the moment,
2256 the following checkpoints are implemented:
2258 Legacy uImage format:
2261 1 common/cmd_bootm.c before attempting to boot an image
2262 -1 common/cmd_bootm.c Image header has bad magic number
2263 2 common/cmd_bootm.c Image header has correct magic number
2264 -2 common/cmd_bootm.c Image header has bad checksum
2265 3 common/cmd_bootm.c Image header has correct checksum
2266 -3 common/cmd_bootm.c Image data has bad checksum
2267 4 common/cmd_bootm.c Image data has correct checksum
2268 -4 common/cmd_bootm.c Image is for unsupported architecture
2269 5 common/cmd_bootm.c Architecture check OK
2270 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2271 6 common/cmd_bootm.c Image Type check OK
2272 -6 common/cmd_bootm.c gunzip uncompression error
2273 -7 common/cmd_bootm.c Unimplemented compression type
2274 7 common/cmd_bootm.c Uncompression OK
2275 8 common/cmd_bootm.c No uncompress/copy overwrite error
2276 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2278 9 common/image.c Start initial ramdisk verification
2279 -10 common/image.c Ramdisk header has bad magic number
2280 -11 common/image.c Ramdisk header has bad checksum
2281 10 common/image.c Ramdisk header is OK
2282 -12 common/image.c Ramdisk data has bad checksum
2283 11 common/image.c Ramdisk data has correct checksum
2284 12 common/image.c Ramdisk verification complete, start loading
2285 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2286 13 common/image.c Start multifile image verification
2287 14 common/image.c No initial ramdisk, no multifile, continue.
2289 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2291 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2292 -31 post/post.c POST test failed, detected by post_output_backlog()
2293 -32 post/post.c POST test failed, detected by post_run_single()
2295 34 common/cmd_doc.c before loading a Image from a DOC device
2296 -35 common/cmd_doc.c Bad usage of "doc" command
2297 35 common/cmd_doc.c correct usage of "doc" command
2298 -36 common/cmd_doc.c No boot device
2299 36 common/cmd_doc.c correct boot device
2300 -37 common/cmd_doc.c Unknown Chip ID on boot device
2301 37 common/cmd_doc.c correct chip ID found, device available
2302 -38 common/cmd_doc.c Read Error on boot device
2303 38 common/cmd_doc.c reading Image header from DOC device OK
2304 -39 common/cmd_doc.c Image header has bad magic number
2305 39 common/cmd_doc.c Image header has correct magic number
2306 -40 common/cmd_doc.c Error reading Image from DOC device
2307 40 common/cmd_doc.c Image header has correct magic number
2308 41 common/cmd_ide.c before loading a Image from a IDE device
2309 -42 common/cmd_ide.c Bad usage of "ide" command
2310 42 common/cmd_ide.c correct usage of "ide" command
2311 -43 common/cmd_ide.c No boot device
2312 43 common/cmd_ide.c boot device found
2313 -44 common/cmd_ide.c Device not available
2314 44 common/cmd_ide.c Device available
2315 -45 common/cmd_ide.c wrong partition selected
2316 45 common/cmd_ide.c partition selected
2317 -46 common/cmd_ide.c Unknown partition table
2318 46 common/cmd_ide.c valid partition table found
2319 -47 common/cmd_ide.c Invalid partition type
2320 47 common/cmd_ide.c correct partition type
2321 -48 common/cmd_ide.c Error reading Image Header on boot device
2322 48 common/cmd_ide.c reading Image Header from IDE device OK
2323 -49 common/cmd_ide.c Image header has bad magic number
2324 49 common/cmd_ide.c Image header has correct magic number
2325 -50 common/cmd_ide.c Image header has bad checksum
2326 50 common/cmd_ide.c Image header has correct checksum
2327 -51 common/cmd_ide.c Error reading Image from IDE device
2328 51 common/cmd_ide.c reading Image from IDE device OK
2329 52 common/cmd_nand.c before loading a Image from a NAND device
2330 -53 common/cmd_nand.c Bad usage of "nand" command
2331 53 common/cmd_nand.c correct usage of "nand" command
2332 -54 common/cmd_nand.c No boot device
2333 54 common/cmd_nand.c boot device found
2334 -55 common/cmd_nand.c Unknown Chip ID on boot device
2335 55 common/cmd_nand.c correct chip ID found, device available
2336 -56 common/cmd_nand.c Error reading Image Header on boot device
2337 56 common/cmd_nand.c reading Image Header from NAND device OK
2338 -57 common/cmd_nand.c Image header has bad magic number
2339 57 common/cmd_nand.c Image header has correct magic number
2340 -58 common/cmd_nand.c Error reading Image from NAND device
2341 58 common/cmd_nand.c reading Image from NAND device OK
2343 -60 common/env_common.c Environment has a bad CRC, using default
2345 64 net/eth.c starting with Ethernet configuration.
2346 -64 net/eth.c no Ethernet found.
2347 65 net/eth.c Ethernet found.
2349 -80 common/cmd_net.c usage wrong
2350 80 common/cmd_net.c before calling NetLoop()
2351 -81 common/cmd_net.c some error in NetLoop() occurred
2352 81 common/cmd_net.c NetLoop() back without error
2353 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2354 82 common/cmd_net.c trying automatic boot
2355 83 common/cmd_net.c running "source" command
2356 -83 common/cmd_net.c some error in automatic boot or "source" command
2357 84 common/cmd_net.c end without errors
2362 100 common/cmd_bootm.c Kernel FIT Image has correct format
2363 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2364 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2365 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2366 102 common/cmd_bootm.c Kernel unit name specified
2367 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2368 103 common/cmd_bootm.c Found configuration node
2369 104 common/cmd_bootm.c Got kernel subimage node offset
2370 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2371 105 common/cmd_bootm.c Kernel subimage hash verification OK
2372 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2373 106 common/cmd_bootm.c Architecture check OK
2374 -106 common/cmd_bootm.c Kernel subimage has wrong type
2375 107 common/cmd_bootm.c Kernel subimage type OK
2376 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2377 108 common/cmd_bootm.c Got kernel subimage data/size
2378 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2379 -109 common/cmd_bootm.c Can't get kernel subimage type
2380 -110 common/cmd_bootm.c Can't get kernel subimage comp
2381 -111 common/cmd_bootm.c Can't get kernel subimage os
2382 -112 common/cmd_bootm.c Can't get kernel subimage load address
2383 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2385 120 common/image.c Start initial ramdisk verification
2386 -120 common/image.c Ramdisk FIT image has incorrect format
2387 121 common/image.c Ramdisk FIT image has correct format
2388 122 common/image.c No ramdisk subimage unit name, using configuration
2389 -122 common/image.c Can't get configuration for ramdisk subimage
2390 123 common/image.c Ramdisk unit name specified
2391 -124 common/image.c Can't get ramdisk subimage node offset
2392 125 common/image.c Got ramdisk subimage node offset
2393 -125 common/image.c Ramdisk subimage hash verification failed
2394 126 common/image.c Ramdisk subimage hash verification OK
2395 -126 common/image.c Ramdisk subimage for unsupported architecture
2396 127 common/image.c Architecture check OK
2397 -127 common/image.c Can't get ramdisk subimage data/size
2398 128 common/image.c Got ramdisk subimage data/size
2399 129 common/image.c Can't get ramdisk load address
2400 -129 common/image.c Got ramdisk load address
2402 -130 common/cmd_doc.c Incorrect FIT image format
2403 131 common/cmd_doc.c FIT image format OK
2405 -140 common/cmd_ide.c Incorrect FIT image format
2406 141 common/cmd_ide.c FIT image format OK
2408 -150 common/cmd_nand.c Incorrect FIT image format
2409 151 common/cmd_nand.c FIT image format OK
2411 - Standalone program support:
2412 CONFIG_STANDALONE_LOAD_ADDR
2414 This option defines a board specific value for the
2415 address where standalone program gets loaded, thus
2416 overwriting the architecture dependent default
2419 - Frame Buffer Address:
2422 Define CONFIG_FB_ADDR if you want to use specific
2423 address for frame buffer.
2424 Then system will reserve the frame buffer address to
2425 defined address instead of lcd_setmem (this function
2426 grabs the memory for frame buffer by panel's size).
2428 Please see board_init_f function.
2430 - Automatic software updates via TFTP server
2432 CONFIG_UPDATE_TFTP_CNT_MAX
2433 CONFIG_UPDATE_TFTP_MSEC_MAX
2435 These options enable and control the auto-update feature;
2436 for a more detailed description refer to doc/README.update.
2438 - MTD Support (mtdparts command, UBI support)
2441 Adds the MTD device infrastructure from the Linux kernel.
2442 Needed for mtdparts command support.
2444 CONFIG_MTD_PARTITIONS
2446 Adds the MTD partitioning infrastructure from the Linux
2447 kernel. Needed for UBI support.
2451 Enable building of SPL globally.
2453 CONFIG_SPL_TEXT_BASE
2454 TEXT_BASE for linking the SPL binary.
2457 LDSCRIPT for linking the SPL binary.
2459 CONFIG_SPL_LIBCOMMON_SUPPORT
2460 Support for common/libcommon.o in SPL binary
2462 CONFIG_SPL_LIBDISK_SUPPORT
2463 Support for disk/libdisk.o in SPL binary
2465 CONFIG_SPL_I2C_SUPPORT
2466 Support for drivers/i2c/libi2c.o in SPL binary
2468 CONFIG_SPL_GPIO_SUPPORT
2469 Support for drivers/gpio/libgpio.o in SPL binary
2471 CONFIG_SPL_MMC_SUPPORT
2472 Support for drivers/mmc/libmmc.o in SPL binary
2474 CONFIG_SPL_SERIAL_SUPPORT
2475 Support for drivers/serial/libserial.o in SPL binary
2477 CONFIG_SPL_SPI_FLASH_SUPPORT
2478 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2480 CONFIG_SPL_SPI_SUPPORT
2481 Support for drivers/spi/libspi.o in SPL binary
2483 CONFIG_SPL_FAT_SUPPORT
2484 Support for fs/fat/libfat.o in SPL binary
2486 CONFIG_SPL_LIBGENERIC_SUPPORT
2487 Support for lib/libgeneric.o in SPL binary
2492 [so far only for SMDK2400 boards]
2494 - Modem support enable:
2495 CONFIG_MODEM_SUPPORT
2497 - RTS/CTS Flow control enable:
2500 - Modem debug support:
2501 CONFIG_MODEM_SUPPORT_DEBUG
2503 Enables debugging stuff (char screen[1024], dbg())
2504 for modem support. Useful only with BDI2000.
2506 - Interrupt support (PPC):
2508 There are common interrupt_init() and timer_interrupt()
2509 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2510 for CPU specific initialization. interrupt_init_cpu()
2511 should set decrementer_count to appropriate value. If
2512 CPU resets decrementer automatically after interrupt
2513 (ppc4xx) it should set decrementer_count to zero.
2514 timer_interrupt() calls timer_interrupt_cpu() for CPU
2515 specific handling. If board has watchdog / status_led
2516 / other_activity_monitor it works automatically from
2517 general timer_interrupt().
2521 In the target system modem support is enabled when a
2522 specific key (key combination) is pressed during
2523 power-on. Otherwise U-Boot will boot normally
2524 (autoboot). The key_pressed() function is called from
2525 board_init(). Currently key_pressed() is a dummy
2526 function, returning 1 and thus enabling modem
2529 If there are no modem init strings in the
2530 environment, U-Boot proceed to autoboot; the
2531 previous output (banner, info printfs) will be
2534 See also: doc/README.Modem
2536 Board initialization settings:
2537 ------------------------------
2539 During Initialization u-boot calls a number of board specific functions
2540 to allow the preparation of board specific prerequisites, e.g. pin setup
2541 before drivers are initialized. To enable these callbacks the
2542 following configuration macros have to be defined. Currently this is
2543 architecture specific, so please check arch/your_architecture/lib/board.c
2544 typically in board_init_f() and board_init_r().
2546 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2547 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2548 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2549 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2551 Configuration Settings:
2552 -----------------------
2554 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2555 undefine this when you're short of memory.
2557 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2558 width of the commands listed in the 'help' command output.
2560 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2561 prompt for user input.
2563 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2565 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2567 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2569 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2570 the application (usually a Linux kernel) when it is
2573 - CONFIG_SYS_BAUDRATE_TABLE:
2574 List of legal baudrate settings for this board.
2576 - CONFIG_SYS_CONSOLE_INFO_QUIET
2577 Suppress display of console information at boot.
2579 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2580 If the board specific function
2581 extern int overwrite_console (void);
2582 returns 1, the stdin, stderr and stdout are switched to the
2583 serial port, else the settings in the environment are used.
2585 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2586 Enable the call to overwrite_console().
2588 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2589 Enable overwrite of previous console environment settings.
2591 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2592 Begin and End addresses of the area used by the
2595 - CONFIG_SYS_ALT_MEMTEST:
2596 Enable an alternate, more extensive memory test.
2598 - CONFIG_SYS_MEMTEST_SCRATCH:
2599 Scratch address used by the alternate memory test
2600 You only need to set this if address zero isn't writeable
2602 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2603 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2604 this specified memory area will get subtracted from the top
2605 (end) of RAM and won't get "touched" at all by U-Boot. By
2606 fixing up gd->ram_size the Linux kernel should gets passed
2607 the now "corrected" memory size and won't touch it either.
2608 This should work for arch/ppc and arch/powerpc. Only Linux
2609 board ports in arch/powerpc with bootwrapper support that
2610 recalculate the memory size from the SDRAM controller setup
2611 will have to get fixed in Linux additionally.
2613 This option can be used as a workaround for the 440EPx/GRx
2614 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2617 WARNING: Please make sure that this value is a multiple of
2618 the Linux page size (normally 4k). If this is not the case,
2619 then the end address of the Linux memory will be located at a
2620 non page size aligned address and this could cause major
2623 - CONFIG_SYS_TFTP_LOADADDR:
2624 Default load address for network file downloads
2626 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2627 Enable temporary baudrate change while serial download
2629 - CONFIG_SYS_SDRAM_BASE:
2630 Physical start address of SDRAM. _Must_ be 0 here.
2632 - CONFIG_SYS_MBIO_BASE:
2633 Physical start address of Motherboard I/O (if using a
2636 - CONFIG_SYS_FLASH_BASE:
2637 Physical start address of Flash memory.
2639 - CONFIG_SYS_MONITOR_BASE:
2640 Physical start address of boot monitor code (set by
2641 make config files to be same as the text base address
2642 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2643 CONFIG_SYS_FLASH_BASE when booting from flash.
2645 - CONFIG_SYS_MONITOR_LEN:
2646 Size of memory reserved for monitor code, used to
2647 determine _at_compile_time_ (!) if the environment is
2648 embedded within the U-Boot image, or in a separate
2651 - CONFIG_SYS_MALLOC_LEN:
2652 Size of DRAM reserved for malloc() use.
2654 - CONFIG_SYS_BOOTM_LEN:
2655 Normally compressed uImages are limited to an
2656 uncompressed size of 8 MBytes. If this is not enough,
2657 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2658 to adjust this setting to your needs.
2660 - CONFIG_SYS_BOOTMAPSZ:
2661 Maximum size of memory mapped by the startup code of
2662 the Linux kernel; all data that must be processed by
2663 the Linux kernel (bd_info, boot arguments, FDT blob if
2664 used) must be put below this limit, unless "bootm_low"
2665 enviroment variable is defined and non-zero. In such case
2666 all data for the Linux kernel must be between "bootm_low"
2667 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2668 variable "bootm_mapsize" will override the value of
2669 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2670 then the value in "bootm_size" will be used instead.
2672 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2673 Enable initrd_high functionality. If defined then the
2674 initrd_high feature is enabled and the bootm ramdisk subcommand
2677 - CONFIG_SYS_BOOT_GET_CMDLINE:
2678 Enables allocating and saving kernel cmdline in space between
2679 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2681 - CONFIG_SYS_BOOT_GET_KBD:
2682 Enables allocating and saving a kernel copy of the bd_info in
2683 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2685 - CONFIG_SYS_MAX_FLASH_BANKS:
2686 Max number of Flash memory banks
2688 - CONFIG_SYS_MAX_FLASH_SECT:
2689 Max number of sectors on a Flash chip
2691 - CONFIG_SYS_FLASH_ERASE_TOUT:
2692 Timeout for Flash erase operations (in ms)
2694 - CONFIG_SYS_FLASH_WRITE_TOUT:
2695 Timeout for Flash write operations (in ms)
2697 - CONFIG_SYS_FLASH_LOCK_TOUT
2698 Timeout for Flash set sector lock bit operation (in ms)
2700 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2701 Timeout for Flash clear lock bits operation (in ms)
2703 - CONFIG_SYS_FLASH_PROTECTION
2704 If defined, hardware flash sectors protection is used
2705 instead of U-Boot software protection.
2707 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2709 Enable TFTP transfers directly to flash memory;
2710 without this option such a download has to be
2711 performed in two steps: (1) download to RAM, and (2)
2712 copy from RAM to flash.
2714 The two-step approach is usually more reliable, since
2715 you can check if the download worked before you erase
2716 the flash, but in some situations (when system RAM is
2717 too limited to allow for a temporary copy of the
2718 downloaded image) this option may be very useful.
2720 - CONFIG_SYS_FLASH_CFI:
2721 Define if the flash driver uses extra elements in the
2722 common flash structure for storing flash geometry.
2724 - CONFIG_FLASH_CFI_DRIVER
2725 This option also enables the building of the cfi_flash driver
2726 in the drivers directory
2728 - CONFIG_FLASH_CFI_MTD
2729 This option enables the building of the cfi_mtd driver
2730 in the drivers directory. The driver exports CFI flash
2733 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2734 Use buffered writes to flash.
2736 - CONFIG_FLASH_SPANSION_S29WS_N
2737 s29ws-n MirrorBit flash has non-standard addresses for buffered
2740 - CONFIG_SYS_FLASH_QUIET_TEST
2741 If this option is defined, the common CFI flash doesn't
2742 print it's warning upon not recognized FLASH banks. This
2743 is useful, if some of the configured banks are only
2744 optionally available.
2746 - CONFIG_FLASH_SHOW_PROGRESS
2747 If defined (must be an integer), print out countdown
2748 digits and dots. Recommended value: 45 (9..1) for 80
2749 column displays, 15 (3..1) for 40 column displays.
2751 - CONFIG_SYS_RX_ETH_BUFFER:
2752 Defines the number of Ethernet receive buffers. On some
2753 Ethernet controllers it is recommended to set this value
2754 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2755 buffers can be full shortly after enabling the interface
2756 on high Ethernet traffic.
2757 Defaults to 4 if not defined.
2759 - CONFIG_ENV_MAX_ENTRIES
2761 Maximum number of entries in the hash table that is used
2762 internally to store the environment settings. The default
2763 setting is supposed to be generous and should work in most
2764 cases. This setting can be used to tune behaviour; see
2765 lib/hashtable.c for details.
2767 The following definitions that deal with the placement and management
2768 of environment data (variable area); in general, we support the
2769 following configurations:
2771 - CONFIG_BUILD_ENVCRC:
2773 Builds up envcrc with the target environment so that external utils
2774 may easily extract it and embed it in final U-Boot images.
2776 - CONFIG_ENV_IS_IN_FLASH:
2778 Define this if the environment is in flash memory.
2780 a) The environment occupies one whole flash sector, which is
2781 "embedded" in the text segment with the U-Boot code. This
2782 happens usually with "bottom boot sector" or "top boot
2783 sector" type flash chips, which have several smaller
2784 sectors at the start or the end. For instance, such a
2785 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2786 such a case you would place the environment in one of the
2787 4 kB sectors - with U-Boot code before and after it. With
2788 "top boot sector" type flash chips, you would put the
2789 environment in one of the last sectors, leaving a gap
2790 between U-Boot and the environment.
2792 - CONFIG_ENV_OFFSET:
2794 Offset of environment data (variable area) to the
2795 beginning of flash memory; for instance, with bottom boot
2796 type flash chips the second sector can be used: the offset
2797 for this sector is given here.
2799 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2803 This is just another way to specify the start address of
2804 the flash sector containing the environment (instead of
2807 - CONFIG_ENV_SECT_SIZE:
2809 Size of the sector containing the environment.
2812 b) Sometimes flash chips have few, equal sized, BIG sectors.
2813 In such a case you don't want to spend a whole sector for
2818 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2819 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2820 of this flash sector for the environment. This saves
2821 memory for the RAM copy of the environment.
2823 It may also save flash memory if you decide to use this
2824 when your environment is "embedded" within U-Boot code,
2825 since then the remainder of the flash sector could be used
2826 for U-Boot code. It should be pointed out that this is
2827 STRONGLY DISCOURAGED from a robustness point of view:
2828 updating the environment in flash makes it always
2829 necessary to erase the WHOLE sector. If something goes
2830 wrong before the contents has been restored from a copy in
2831 RAM, your target system will be dead.
2833 - CONFIG_ENV_ADDR_REDUND
2834 CONFIG_ENV_SIZE_REDUND
2836 These settings describe a second storage area used to hold
2837 a redundant copy of the environment data, so that there is
2838 a valid backup copy in case there is a power failure during
2839 a "saveenv" operation.
2841 BE CAREFUL! Any changes to the flash layout, and some changes to the
2842 source code will make it necessary to adapt <board>/u-boot.lds*
2846 - CONFIG_ENV_IS_IN_NVRAM:
2848 Define this if you have some non-volatile memory device
2849 (NVRAM, battery buffered SRAM) which you want to use for the
2855 These two #defines are used to determine the memory area you
2856 want to use for environment. It is assumed that this memory
2857 can just be read and written to, without any special
2860 BE CAREFUL! The first access to the environment happens quite early
2861 in U-Boot initalization (when we try to get the setting of for the
2862 console baudrate). You *MUST* have mapped your NVRAM area then, or
2865 Please note that even with NVRAM we still use a copy of the
2866 environment in RAM: we could work on NVRAM directly, but we want to
2867 keep settings there always unmodified except somebody uses "saveenv"
2868 to save the current settings.
2871 - CONFIG_ENV_IS_IN_EEPROM:
2873 Use this if you have an EEPROM or similar serial access
2874 device and a driver for it.
2876 - CONFIG_ENV_OFFSET:
2879 These two #defines specify the offset and size of the
2880 environment area within the total memory of your EEPROM.
2882 - CONFIG_SYS_I2C_EEPROM_ADDR:
2883 If defined, specified the chip address of the EEPROM device.
2884 The default address is zero.
2886 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2887 If defined, the number of bits used to address bytes in a
2888 single page in the EEPROM device. A 64 byte page, for example
2889 would require six bits.
2891 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2892 If defined, the number of milliseconds to delay between
2893 page writes. The default is zero milliseconds.
2895 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2896 The length in bytes of the EEPROM memory array address. Note
2897 that this is NOT the chip address length!
2899 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2900 EEPROM chips that implement "address overflow" are ones
2901 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2902 address and the extra bits end up in the "chip address" bit
2903 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2906 Note that we consider the length of the address field to
2907 still be one byte because the extra address bits are hidden
2908 in the chip address.
2910 - CONFIG_SYS_EEPROM_SIZE:
2911 The size in bytes of the EEPROM device.
2913 - CONFIG_ENV_EEPROM_IS_ON_I2C
2914 define this, if you have I2C and SPI activated, and your
2915 EEPROM, which holds the environment, is on the I2C bus.
2917 - CONFIG_I2C_ENV_EEPROM_BUS
2918 if you have an Environment on an EEPROM reached over
2919 I2C muxes, you can define here, how to reach this
2920 EEPROM. For example:
2922 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2924 EEPROM which holds the environment, is reached over
2925 a pca9547 i2c mux with address 0x70, channel 3.
2927 - CONFIG_ENV_IS_IN_DATAFLASH:
2929 Define this if you have a DataFlash memory device which you
2930 want to use for the environment.
2932 - CONFIG_ENV_OFFSET:
2936 These three #defines specify the offset and size of the
2937 environment area within the total memory of your DataFlash placed
2938 at the specified address.
2940 - CONFIG_ENV_IS_IN_NAND:
2942 Define this if you have a NAND device which you want to use
2943 for the environment.
2945 - CONFIG_ENV_OFFSET:
2948 These two #defines specify the offset and size of the environment
2949 area within the first NAND device. CONFIG_ENV_OFFSET must be
2950 aligned to an erase block boundary.
2952 - CONFIG_ENV_OFFSET_REDUND (optional):
2954 This setting describes a second storage area of CONFIG_ENV_SIZE
2955 size used to hold a redundant copy of the environment data, so
2956 that there is a valid backup copy in case there is a power failure
2957 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2958 aligned to an erase block boundary.
2960 - CONFIG_ENV_RANGE (optional):
2962 Specifies the length of the region in which the environment
2963 can be written. This should be a multiple of the NAND device's
2964 block size. Specifying a range with more erase blocks than
2965 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2966 the range to be avoided.
2968 - CONFIG_ENV_OFFSET_OOB (optional):
2970 Enables support for dynamically retrieving the offset of the
2971 environment from block zero's out-of-band data. The
2972 "nand env.oob" command can be used to record this offset.
2973 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2974 using CONFIG_ENV_OFFSET_OOB.
2976 - CONFIG_NAND_ENV_DST
2978 Defines address in RAM to which the nand_spl code should copy the
2979 environment. If redundant environment is used, it will be copied to
2980 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2982 - CONFIG_SYS_SPI_INIT_OFFSET
2984 Defines offset to the initial SPI buffer area in DPRAM. The
2985 area is used at an early stage (ROM part) if the environment
2986 is configured to reside in the SPI EEPROM: We need a 520 byte
2987 scratch DPRAM area. It is used between the two initialization
2988 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2989 to be a good choice since it makes it far enough from the
2990 start of the data area as well as from the stack pointer.
2992 Please note that the environment is read-only until the monitor
2993 has been relocated to RAM and a RAM copy of the environment has been
2994 created; also, when using EEPROM you will have to use getenv_f()
2995 until then to read environment variables.
2997 The environment is protected by a CRC32 checksum. Before the monitor
2998 is relocated into RAM, as a result of a bad CRC you will be working
2999 with the compiled-in default environment - *silently*!!! [This is
3000 necessary, because the first environment variable we need is the
3001 "baudrate" setting for the console - if we have a bad CRC, we don't
3002 have any device yet where we could complain.]
3004 Note: once the monitor has been relocated, then it will complain if
3005 the default environment is used; a new CRC is computed as soon as you
3006 use the "saveenv" command to store a valid environment.
3008 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3009 Echo the inverted Ethernet link state to the fault LED.
3011 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3012 also needs to be defined.
3014 - CONFIG_SYS_FAULT_MII_ADDR:
3015 MII address of the PHY to check for the Ethernet link state.
3017 - CONFIG_NS16550_MIN_FUNCTIONS:
3018 Define this if you desire to only have use of the NS16550_init
3019 and NS16550_putc functions for the serial driver located at
3020 drivers/serial/ns16550.c. This option is useful for saving
3021 space for already greatly restricted images, including but not
3022 limited to NAND_SPL configurations.
3024 Low Level (hardware related) configuration options:
3025 ---------------------------------------------------
3027 - CONFIG_SYS_CACHELINE_SIZE:
3028 Cache Line Size of the CPU.
3030 - CONFIG_SYS_DEFAULT_IMMR:
3031 Default address of the IMMR after system reset.
3033 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3034 and RPXsuper) to be able to adjust the position of
3035 the IMMR register after a reset.
3037 - CONFIG_SYS_CCSRBAR_DEFAULT:
3038 Default (power-on reset) physical address of CCSR on Freescale
3041 - CONFIG_SYS_CCSRBAR:
3042 Virtual address of CCSR. On a 32-bit build, this is typically
3043 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3045 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3046 for cross-platform code that uses that macro instead.
3048 - CONFIG_SYS_CCSRBAR_PHYS:
3049 Physical address of CCSR. CCSR can be relocated to a new
3050 physical address, if desired. In this case, this macro should
3051 be set to that address. Otherwise, it should be set to the
3052 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3053 is typically relocated on 36-bit builds. It is recommended
3054 that this macro be defined via the _HIGH and _LOW macros:
3056 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3057 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3059 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3060 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3061 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3062 used in assembly code, so it must not contain typecasts or
3063 integer size suffixes (e.g. "ULL").
3065 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3066 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3067 used in assembly code, so it must not contain typecasts or
3068 integer size suffixes (e.g. "ULL").
3070 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3071 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3072 forced to a value that ensures that CCSR is not relocated.
3074 - Floppy Disk Support:
3075 CONFIG_SYS_FDC_DRIVE_NUMBER
3077 the default drive number (default value 0)
3079 CONFIG_SYS_ISA_IO_STRIDE
3081 defines the spacing between FDC chipset registers
3084 CONFIG_SYS_ISA_IO_OFFSET
3086 defines the offset of register from address. It
3087 depends on which part of the data bus is connected to
3088 the FDC chipset. (default value 0)
3090 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3091 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3094 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3095 fdc_hw_init() is called at the beginning of the FDC
3096 setup. fdc_hw_init() must be provided by the board
3097 source code. It is used to make hardware dependant
3101 Most IDE controllers were designed to be connected with PCI
3102 interface. Only few of them were designed for AHB interface.
3103 When software is doing ATA command and data transfer to
3104 IDE devices through IDE-AHB controller, some additional
3105 registers accessing to these kind of IDE-AHB controller
3108 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3109 DO NOT CHANGE unless you know exactly what you're
3110 doing! (11-4) [MPC8xx/82xx systems only]
3112 - CONFIG_SYS_INIT_RAM_ADDR:
3114 Start address of memory area that can be used for
3115 initial data and stack; please note that this must be
3116 writable memory that is working WITHOUT special
3117 initialization, i. e. you CANNOT use normal RAM which
3118 will become available only after programming the
3119 memory controller and running certain initialization
3122 U-Boot uses the following memory types:
3123 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3124 - MPC824X: data cache
3125 - PPC4xx: data cache
3127 - CONFIG_SYS_GBL_DATA_OFFSET:
3129 Offset of the initial data structure in the memory
3130 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3131 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3132 data is located at the end of the available space
3133 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3134 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3135 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3136 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3139 On the MPC824X (or other systems that use the data
3140 cache for initial memory) the address chosen for
3141 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3142 point to an otherwise UNUSED address space between
3143 the top of RAM and the start of the PCI space.
3145 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3147 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3149 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3151 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3153 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3155 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3157 - CONFIG_SYS_OR_TIMING_SDRAM:
3160 - CONFIG_SYS_MAMR_PTA:
3161 periodic timer for refresh
3163 - CONFIG_SYS_DER: Debug Event Register (37-47)
3165 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3166 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3167 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3168 CONFIG_SYS_BR1_PRELIM:
3169 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3171 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3172 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3173 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3174 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3176 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3177 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3178 Machine Mode Register and Memory Periodic Timer
3179 Prescaler definitions (SDRAM timing)
3181 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3182 enable I2C microcode relocation patch (MPC8xx);
3183 define relocation offset in DPRAM [DSP2]
3185 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3186 enable SMC microcode relocation patch (MPC8xx);
3187 define relocation offset in DPRAM [SMC1]
3189 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3190 enable SPI microcode relocation patch (MPC8xx);
3191 define relocation offset in DPRAM [SCC4]
3193 - CONFIG_SYS_USE_OSCCLK:
3194 Use OSCM clock mode on MBX8xx board. Be careful,
3195 wrong setting might damage your board. Read
3196 doc/README.MBX before setting this variable!
3198 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3199 Offset of the bootmode word in DPRAM used by post
3200 (Power On Self Tests). This definition overrides
3201 #define'd default value in commproc.h resp.
3204 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3205 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3206 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3207 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3208 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3209 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3210 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3211 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3212 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3214 - CONFIG_PCI_DISABLE_PCIE:
3215 Disable PCI-Express on systems where it is supported but not
3219 Chip has SRIO or not
3222 Board has SRIO 1 port available
3225 Board has SRIO 2 port available
3227 - CONFIG_SYS_SRIOn_MEM_VIRT:
3228 Virtual Address of SRIO port 'n' memory region
3230 - CONFIG_SYS_SRIOn_MEM_PHYS:
3231 Physical Address of SRIO port 'n' memory region
3233 - CONFIG_SYS_SRIOn_MEM_SIZE:
3234 Size of SRIO port 'n' memory region
3236 - CONFIG_SYS_NDFC_16
3237 Defined to tell the NDFC that the NAND chip is using a
3240 - CONFIG_SYS_NDFC_EBC0_CFG
3241 Sets the EBC0_CFG register for the NDFC. If not defined
3242 a default value will be used.
3245 Get DDR timing information from an I2C EEPROM. Common
3246 with pluggable memory modules such as SODIMMs
3249 I2C address of the SPD EEPROM
3251 - CONFIG_SYS_SPD_BUS_NUM
3252 If SPD EEPROM is on an I2C bus other than the first
3253 one, specify here. Note that the value must resolve
3254 to something your driver can deal with.
3256 - CONFIG_SYS_DDR_RAW_TIMING
3257 Get DDR timing information from other than SPD. Common with
3258 soldered DDR chips onboard without SPD. DDR raw timing
3259 parameters are extracted from datasheet and hard-coded into
3260 header files or board specific files.
3262 - CONFIG_FSL_DDR_INTERACTIVE
3263 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3265 - CONFIG_SYS_83XX_DDR_USES_CS0
3266 Only for 83xx systems. If specified, then DDR should
3267 be configured using CS0 and CS1 instead of CS2 and CS3.
3269 - CONFIG_ETHER_ON_FEC[12]
3270 Define to enable FEC[12] on a 8xx series processor.
3272 - CONFIG_FEC[12]_PHY
3273 Define to the hardcoded PHY address which corresponds
3274 to the given FEC; i. e.
3275 #define CONFIG_FEC1_PHY 4
3276 means that the PHY with address 4 is connected to FEC1
3278 When set to -1, means to probe for first available.
3280 - CONFIG_FEC[12]_PHY_NORXERR
3281 The PHY does not have a RXERR line (RMII only).
3282 (so program the FEC to ignore it).
3285 Enable RMII mode for all FECs.
3286 Note that this is a global option, we can't
3287 have one FEC in standard MII mode and another in RMII mode.
3289 - CONFIG_CRC32_VERIFY
3290 Add a verify option to the crc32 command.
3293 => crc32 -v <address> <count> <crc32>
3295 Where address/count indicate a memory area
3296 and crc32 is the correct crc32 which the
3300 Add the "loopw" memory command. This only takes effect if
3301 the memory commands are activated globally (CONFIG_CMD_MEM).
3304 Add the "mdc" and "mwc" memory commands. These are cyclic
3309 This command will print 4 bytes (10,11,12,13) each 500 ms.
3311 => mwc.l 100 12345678 10
3312 This command will write 12345678 to address 100 all 10 ms.
3314 This only takes effect if the memory commands are activated
3315 globally (CONFIG_CMD_MEM).
3317 - CONFIG_SKIP_LOWLEVEL_INIT
3318 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3319 low level initializations (like setting up the memory
3320 controller) are omitted and/or U-Boot does not
3321 relocate itself into RAM.
3323 Normally this variable MUST NOT be defined. The only
3324 exception is when U-Boot is loaded (to RAM) by some
3325 other boot loader or by a debugger which performs
3326 these initializations itself.
3329 Modifies the behaviour of start.S when compiling a loader
3330 that is executed before the actual U-Boot. E.g. when
3331 compiling a NAND SPL.
3333 - CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3334 define this, if you want to read first the oob data
3335 and then the data. This is used for example on
3338 - CONFIG_USE_ARCH_MEMCPY
3339 CONFIG_USE_ARCH_MEMSET
3340 If these options are used a optimized version of memcpy/memset will
3341 be used if available. These functions may be faster under some
3342 conditions but may increase the binary size.
3344 Freescale QE/FMAN Firmware Support:
3345 -----------------------------------
3347 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3348 loading of "firmware", which is encoded in the QE firmware binary format.
3349 This firmware often needs to be loaded during U-Boot booting, so macros
3350 are used to identify the storage device (NOR flash, SPI, etc) and the address
3353 - CONFIG_SYS_QE_FMAN_FW_ADDR
3354 The address in the storage device where the firmware is located. The
3355 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3358 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3359 The maximum possible size of the firmware. The firmware binary format
3360 has a field that specifies the actual size of the firmware, but it
3361 might not be possible to read any part of the firmware unless some
3362 local storage is allocated to hold the entire firmware first.
3364 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3365 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3366 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3367 virtual address in NOR flash.
3369 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3370 Specifies that QE/FMAN firmware is located in NAND flash.
3371 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3373 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3374 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3375 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3377 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3378 Specifies that QE/FMAN firmware is located on the primary SPI
3379 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3382 Building the Software:
3383 ======================
3385 Building U-Boot has been tested in several native build environments
3386 and in many different cross environments. Of course we cannot support
3387 all possibly existing versions of cross development tools in all
3388 (potentially obsolete) versions. In case of tool chain problems we
3389 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3390 which is extensively used to build and test U-Boot.
3392 If you are not using a native environment, it is assumed that you
3393 have GNU cross compiling tools available in your path. In this case,
3394 you must set the environment variable CROSS_COMPILE in your shell.
3395 Note that no changes to the Makefile or any other source files are
3396 necessary. For example using the ELDK on a 4xx CPU, please enter:
3398 $ CROSS_COMPILE=ppc_4xx-
3399 $ export CROSS_COMPILE
3401 Note: If you wish to generate Windows versions of the utilities in
3402 the tools directory you can use the MinGW toolchain
3403 (http://www.mingw.org). Set your HOST tools to the MinGW
3404 toolchain and execute 'make tools'. For example:
3406 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3408 Binaries such as tools/mkimage.exe will be created which can
3409 be executed on computers running Windows.
3411 U-Boot is intended to be simple to build. After installing the
3412 sources you must configure U-Boot for one specific board type. This
3417 where "NAME_config" is the name of one of the existing configu-
3418 rations; see the main Makefile for supported names.
3420 Note: for some board special configuration names may exist; check if
3421 additional information is available from the board vendor; for
3422 instance, the TQM823L systems are available without (standard)
3423 or with LCD support. You can select such additional "features"
3424 when choosing the configuration, i. e.
3427 - will configure for a plain TQM823L, i. e. no LCD support
3429 make TQM823L_LCD_config
3430 - will configure for a TQM823L with U-Boot console on LCD
3435 Finally, type "make all", and you should get some working U-Boot
3436 images ready for download to / installation on your system:
3438 - "u-boot.bin" is a raw binary image
3439 - "u-boot" is an image in ELF binary format
3440 - "u-boot.srec" is in Motorola S-Record format
3442 By default the build is performed locally and the objects are saved
3443 in the source directory. One of the two methods can be used to change
3444 this behavior and build U-Boot to some external directory:
3446 1. Add O= to the make command line invocations:
3448 make O=/tmp/build distclean
3449 make O=/tmp/build NAME_config
3450 make O=/tmp/build all
3452 2. Set environment variable BUILD_DIR to point to the desired location:
3454 export BUILD_DIR=/tmp/build
3459 Note that the command line "O=" setting overrides the BUILD_DIR environment
3463 Please be aware that the Makefiles assume you are using GNU make, so
3464 for instance on NetBSD you might need to use "gmake" instead of
3468 If the system board that you have is not listed, then you will need
3469 to port U-Boot to your hardware platform. To do this, follow these
3472 1. Add a new configuration option for your board to the toplevel
3473 "Makefile" and to the "MAKEALL" script, using the existing
3474 entries as examples. Note that here and at many other places
3475 boards and other names are listed in alphabetical sort order. Please
3477 2. Create a new directory to hold your board specific code. Add any
3478 files you need. In your board directory, you will need at least
3479 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3480 3. Create a new configuration file "include/configs/<board>.h" for
3482 3. If you're porting U-Boot to a new CPU, then also create a new
3483 directory to hold your CPU specific code. Add any files you need.
3484 4. Run "make <board>_config" with your new name.
3485 5. Type "make", and you should get a working "u-boot.srec" file
3486 to be installed on your target system.
3487 6. Debug and solve any problems that might arise.
3488 [Of course, this last step is much harder than it sounds.]
3491 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3492 ==============================================================
3494 If you have modified U-Boot sources (for instance added a new board
3495 or support for new devices, a new CPU, etc.) you are expected to
3496 provide feedback to the other developers. The feedback normally takes
3497 the form of a "patch", i. e. a context diff against a certain (latest
3498 official or latest in the git repository) version of U-Boot sources.
3500 But before you submit such a patch, please verify that your modifi-
3501 cation did not break existing code. At least make sure that *ALL* of
3502 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3503 just run the "MAKEALL" script, which will configure and build U-Boot
3504 for ALL supported system. Be warned, this will take a while. You can
3505 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3506 environment variable to the script, i. e. to use the ELDK cross tools
3509 CROSS_COMPILE=ppc_8xx- MAKEALL
3511 or to build on a native PowerPC system you can type
3513 CROSS_COMPILE=' ' MAKEALL
3515 When using the MAKEALL script, the default behaviour is to build
3516 U-Boot in the source directory. This location can be changed by
3517 setting the BUILD_DIR environment variable. Also, for each target
3518 built, the MAKEALL script saves two log files (<target>.ERR and
3519 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3520 location can be changed by setting the MAKEALL_LOGDIR environment
3521 variable. For example:
3523 export BUILD_DIR=/tmp/build
3524 export MAKEALL_LOGDIR=/tmp/log
3525 CROSS_COMPILE=ppc_8xx- MAKEALL
3527 With the above settings build objects are saved in the /tmp/build,
3528 log files are saved in the /tmp/log and the source tree remains clean
3529 during the whole build process.
3532 See also "U-Boot Porting Guide" below.
3535 Monitor Commands - Overview:
3536 ============================
3538 go - start application at address 'addr'
3539 run - run commands in an environment variable
3540 bootm - boot application image from memory
3541 bootp - boot image via network using BootP/TFTP protocol
3542 tftpboot- boot image via network using TFTP protocol
3543 and env variables "ipaddr" and "serverip"
3544 (and eventually "gatewayip")
3545 tftpput - upload a file via network using TFTP protocol
3546 rarpboot- boot image via network using RARP/TFTP protocol
3547 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3548 loads - load S-Record file over serial line
3549 loadb - load binary file over serial line (kermit mode)
3551 mm - memory modify (auto-incrementing)
3552 nm - memory modify (constant address)
3553 mw - memory write (fill)
3555 cmp - memory compare
3556 crc32 - checksum calculation
3557 i2c - I2C sub-system
3558 sspi - SPI utility commands
3559 base - print or set address offset
3560 printenv- print environment variables
3561 setenv - set environment variables
3562 saveenv - save environment variables to persistent storage
3563 protect - enable or disable FLASH write protection
3564 erase - erase FLASH memory
3565 flinfo - print FLASH memory information
3566 bdinfo - print Board Info structure
3567 iminfo - print header information for application image
3568 coninfo - print console devices and informations
3569 ide - IDE sub-system
3570 loop - infinite loop on address range
3571 loopw - infinite write loop on address range
3572 mtest - simple RAM test
3573 icache - enable or disable instruction cache
3574 dcache - enable or disable data cache
3575 reset - Perform RESET of the CPU
3576 echo - echo args to console
3577 version - print monitor version
3578 help - print online help
3579 ? - alias for 'help'
3582 Monitor Commands - Detailed Description:
3583 ========================================
3587 For now: just type "help <command>".
3590 Environment Variables:
3591 ======================
3593 U-Boot supports user configuration using Environment Variables which
3594 can be made persistent by saving to Flash memory.
3596 Environment Variables are set using "setenv", printed using
3597 "printenv", and saved to Flash using "saveenv". Using "setenv"
3598 without a value can be used to delete a variable from the
3599 environment. As long as you don't save the environment you are
3600 working with an in-memory copy. In case the Flash area containing the
3601 environment is erased by accident, a default environment is provided.
3603 Some configuration options can be set using Environment Variables.
3605 List of environment variables (most likely not complete):
3607 baudrate - see CONFIG_BAUDRATE
3609 bootdelay - see CONFIG_BOOTDELAY
3611 bootcmd - see CONFIG_BOOTCOMMAND
3613 bootargs - Boot arguments when booting an RTOS image
3615 bootfile - Name of the image to load with TFTP
3617 bootm_low - Memory range available for image processing in the bootm
3618 command can be restricted. This variable is given as
3619 a hexadecimal number and defines lowest address allowed
3620 for use by the bootm command. See also "bootm_size"
3621 environment variable. Address defined by "bootm_low" is
3622 also the base of the initial memory mapping for the Linux
3623 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3626 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3627 This variable is given as a hexadecimal number and it
3628 defines the size of the memory region starting at base
3629 address bootm_low that is accessible by the Linux kernel
3630 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3631 as the default value if it is defined, and bootm_size is
3634 bootm_size - Memory range available for image processing in the bootm
3635 command can be restricted. This variable is given as
3636 a hexadecimal number and defines the size of the region
3637 allowed for use by the bootm command. See also "bootm_low"
3638 environment variable.
3640 updatefile - Location of the software update file on a TFTP server, used
3641 by the automatic software update feature. Please refer to
3642 documentation in doc/README.update for more details.
3644 autoload - if set to "no" (any string beginning with 'n'),
3645 "bootp" will just load perform a lookup of the
3646 configuration from the BOOTP server, but not try to
3647 load any image using TFTP
3649 autostart - if set to "yes", an image loaded using the "bootp",
3650 "rarpboot", "tftpboot" or "diskboot" commands will
3651 be automatically started (by internally calling
3654 If set to "no", a standalone image passed to the
3655 "bootm" command will be copied to the load address
3656 (and eventually uncompressed), but NOT be started.
3657 This can be used to load and uncompress arbitrary
3660 fdt_high - if set this restricts the maximum address that the
3661 flattened device tree will be copied into upon boot.
3662 If this is set to the special value 0xFFFFFFFF then
3663 the fdt will not be copied at all on boot. For this
3664 to work it must reside in writable memory, have
3665 sufficient padding on the end of it for u-boot to
3666 add the information it needs into it, and the memory
3667 must be accessible by the kernel.
3669 fdtcontroladdr- if set this is the address of the control flattened
3670 device tree used by U-Boot when CONFIG_OF_CONTROL is
3673 i2cfast - (PPC405GP|PPC405EP only)
3674 if set to 'y' configures Linux I2C driver for fast
3675 mode (400kHZ). This environment variable is used in
3676 initialization code. So, for changes to be effective
3677 it must be saved and board must be reset.
3679 initrd_high - restrict positioning of initrd images:
3680 If this variable is not set, initrd images will be
3681 copied to the highest possible address in RAM; this
3682 is usually what you want since it allows for
3683 maximum initrd size. If for some reason you want to
3684 make sure that the initrd image is loaded below the
3685 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3686 variable to a value of "no" or "off" or "0".
3687 Alternatively, you can set it to a maximum upper
3688 address to use (U-Boot will still check that it
3689 does not overwrite the U-Boot stack and data).
3691 For instance, when you have a system with 16 MB
3692 RAM, and want to reserve 4 MB from use by Linux,
3693 you can do this by adding "mem=12M" to the value of
3694 the "bootargs" variable. However, now you must make
3695 sure that the initrd image is placed in the first
3696 12 MB as well - this can be done with
3698 setenv initrd_high 00c00000
3700 If you set initrd_high to 0xFFFFFFFF, this is an
3701 indication to U-Boot that all addresses are legal
3702 for the Linux kernel, including addresses in flash
3703 memory. In this case U-Boot will NOT COPY the
3704 ramdisk at all. This may be useful to reduce the
3705 boot time on your system, but requires that this
3706 feature is supported by your Linux kernel.
3708 ipaddr - IP address; needed for tftpboot command
3710 loadaddr - Default load address for commands like "bootp",
3711 "rarpboot", "tftpboot", "loadb" or "diskboot"
3713 loads_echo - see CONFIG_LOADS_ECHO
3715 serverip - TFTP server IP address; needed for tftpboot command
3717 bootretry - see CONFIG_BOOT_RETRY_TIME
3719 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3721 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3723 ethprime - controls which interface is used first.
3725 ethact - controls which interface is currently active.
3726 For example you can do the following
3728 => setenv ethact FEC
3729 => ping 192.168.0.1 # traffic sent on FEC
3730 => setenv ethact SCC
3731 => ping 10.0.0.1 # traffic sent on SCC
3733 ethrotate - When set to "no" U-Boot does not go through all
3734 available network interfaces.
3735 It just stays at the currently selected interface.
3737 netretry - When set to "no" each network operation will
3738 either succeed or fail without retrying.
3739 When set to "once" the network operation will
3740 fail when all the available network interfaces
3741 are tried once without success.
3742 Useful on scripts which control the retry operation
3745 npe_ucode - set load address for the NPE microcode
3747 tftpsrcport - If this is set, the value is used for TFTP's
3750 tftpdstport - If this is set, the value is used for TFTP's UDP
3751 destination port instead of the Well Know Port 69.
3753 tftpblocksize - Block size to use for TFTP transfers; if not set,
3754 we use the TFTP server's default block size
3756 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3757 seconds, minimum value is 1000 = 1 second). Defines
3758 when a packet is considered to be lost so it has to
3759 be retransmitted. The default is 5000 = 5 seconds.
3760 Lowering this value may make downloads succeed
3761 faster in networks with high packet loss rates or
3762 with unreliable TFTP servers.
3764 vlan - When set to a value < 4095 the traffic over
3765 Ethernet is encapsulated/received over 802.1q
3768 The following image location variables contain the location of images
3769 used in booting. The "Image" column gives the role of the image and is
3770 not an environment variable name. The other columns are environment
3771 variable names. "File Name" gives the name of the file on a TFTP
3772 server, "RAM Address" gives the location in RAM the image will be
3773 loaded to, and "Flash Location" gives the image's address in NOR
3774 flash or offset in NAND flash.
3776 *Note* - these variables don't have to be defined for all boards, some
3777 boards currenlty use other variables for these purposes, and some
3778 boards use these variables for other purposes.
3780 Image File Name RAM Address Flash Location
3781 ----- --------- ----------- --------------
3782 u-boot u-boot u-boot_addr_r u-boot_addr
3783 Linux kernel bootfile kernel_addr_r kernel_addr
3784 device tree blob fdtfile fdt_addr_r fdt_addr
3785 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3787 The following environment variables may be used and automatically
3788 updated by the network boot commands ("bootp" and "rarpboot"),
3789 depending the information provided by your boot server:
3791 bootfile - see above
3792 dnsip - IP address of your Domain Name Server
3793 dnsip2 - IP address of your secondary Domain Name Server
3794 gatewayip - IP address of the Gateway (Router) to use
3795 hostname - Target hostname
3797 netmask - Subnet Mask
3798 rootpath - Pathname of the root filesystem on the NFS server
3799 serverip - see above
3802 There are two special Environment Variables:
3804 serial# - contains hardware identification information such
3805 as type string and/or serial number
3806 ethaddr - Ethernet address
3808 These variables can be set only once (usually during manufacturing of
3809 the board). U-Boot refuses to delete or overwrite these variables
3810 once they have been set once.
3813 Further special Environment Variables:
3815 ver - Contains the U-Boot version string as printed
3816 with the "version" command. This variable is
3817 readonly (see CONFIG_VERSION_VARIABLE).
3820 Please note that changes to some configuration parameters may take
3821 only effect after the next boot (yes, that's just like Windoze :-).
3824 Command Line Parsing:
3825 =====================
3827 There are two different command line parsers available with U-Boot:
3828 the old "simple" one, and the much more powerful "hush" shell:
3830 Old, simple command line parser:
3831 --------------------------------
3833 - supports environment variables (through setenv / saveenv commands)
3834 - several commands on one line, separated by ';'
3835 - variable substitution using "... ${name} ..." syntax
3836 - special characters ('$', ';') can be escaped by prefixing with '\',
3838 setenv bootcmd bootm \${address}
3839 - You can also escape text by enclosing in single apostrophes, for example:
3840 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3845 - similar to Bourne shell, with control structures like
3846 if...then...else...fi, for...do...done; while...do...done,
3847 until...do...done, ...
3848 - supports environment ("global") variables (through setenv / saveenv
3849 commands) and local shell variables (through standard shell syntax
3850 "name=value"); only environment variables can be used with "run"
3856 (1) If a command line (or an environment variable executed by a "run"
3857 command) contains several commands separated by semicolon, and
3858 one of these commands fails, then the remaining commands will be
3861 (2) If you execute several variables with one call to run (i. e.
3862 calling run with a list of variables as arguments), any failing
3863 command will cause "run" to terminate, i. e. the remaining
3864 variables are not executed.
3866 Note for Redundant Ethernet Interfaces:
3867 =======================================
3869 Some boards come with redundant Ethernet interfaces; U-Boot supports
3870 such configurations and is capable of automatic selection of a
3871 "working" interface when needed. MAC assignment works as follows:
3873 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3874 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3875 "eth1addr" (=>eth1), "eth2addr", ...
3877 If the network interface stores some valid MAC address (for instance
3878 in SROM), this is used as default address if there is NO correspon-
3879 ding setting in the environment; if the corresponding environment
3880 variable is set, this overrides the settings in the card; that means:
3882 o If the SROM has a valid MAC address, and there is no address in the
3883 environment, the SROM's address is used.
3885 o If there is no valid address in the SROM, and a definition in the
3886 environment exists, then the value from the environment variable is
3889 o If both the SROM and the environment contain a MAC address, and
3890 both addresses are the same, this MAC address is used.
3892 o If both the SROM and the environment contain a MAC address, and the
3893 addresses differ, the value from the environment is used and a
3896 o If neither SROM nor the environment contain a MAC address, an error
3899 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3900 will be programmed into hardware as part of the initialization process. This
3901 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3902 The naming convention is as follows:
3903 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3908 U-Boot is capable of booting (and performing other auxiliary operations on)
3909 images in two formats:
3911 New uImage format (FIT)
3912 -----------------------
3914 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3915 to Flattened Device Tree). It allows the use of images with multiple
3916 components (several kernels, ramdisks, etc.), with contents protected by
3917 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3923 Old image format is based on binary files which can be basically anything,
3924 preceded by a special header; see the definitions in include/image.h for
3925 details; basically, the header defines the following image properties:
3927 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3928 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3929 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3930 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3932 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3933 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3934 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3935 * Compression Type (uncompressed, gzip, bzip2)
3941 The header is marked by a special Magic Number, and both the header
3942 and the data portions of the image are secured against corruption by
3949 Although U-Boot should support any OS or standalone application
3950 easily, the main focus has always been on Linux during the design of
3953 U-Boot includes many features that so far have been part of some
3954 special "boot loader" code within the Linux kernel. Also, any
3955 "initrd" images to be used are no longer part of one big Linux image;
3956 instead, kernel and "initrd" are separate images. This implementation
3957 serves several purposes:
3959 - the same features can be used for other OS or standalone
3960 applications (for instance: using compressed images to reduce the
3961 Flash memory footprint)
3963 - it becomes much easier to port new Linux kernel versions because
3964 lots of low-level, hardware dependent stuff are done by U-Boot
3966 - the same Linux kernel image can now be used with different "initrd"
3967 images; of course this also means that different kernel images can
3968 be run with the same "initrd". This makes testing easier (you don't
3969 have to build a new "zImage.initrd" Linux image when you just
3970 change a file in your "initrd"). Also, a field-upgrade of the
3971 software is easier now.
3977 Porting Linux to U-Boot based systems:
3978 ---------------------------------------
3980 U-Boot cannot save you from doing all the necessary modifications to
3981 configure the Linux device drivers for use with your target hardware
3982 (no, we don't intend to provide a full virtual machine interface to
3985 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3987 Just make sure your machine specific header file (for instance
3988 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3989 Information structure as we define in include/asm-<arch>/u-boot.h,
3990 and make sure that your definition of IMAP_ADDR uses the same value
3991 as your U-Boot configuration in CONFIG_SYS_IMMR.
3994 Configuring the Linux kernel:
3995 -----------------------------
3997 No specific requirements for U-Boot. Make sure you have some root
3998 device (initial ramdisk, NFS) for your target system.
4001 Building a Linux Image:
4002 -----------------------
4004 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4005 not used. If you use recent kernel source, a new build target
4006 "uImage" will exist which automatically builds an image usable by
4007 U-Boot. Most older kernels also have support for a "pImage" target,
4008 which was introduced for our predecessor project PPCBoot and uses a
4009 100% compatible format.
4018 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4019 encapsulate a compressed Linux kernel image with header information,
4020 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4022 * build a standard "vmlinux" kernel image (in ELF binary format):
4024 * convert the kernel into a raw binary image:
4026 ${CROSS_COMPILE}-objcopy -O binary \
4027 -R .note -R .comment \
4028 -S vmlinux linux.bin
4030 * compress the binary image:
4034 * package compressed binary image for U-Boot:
4036 mkimage -A ppc -O linux -T kernel -C gzip \
4037 -a 0 -e 0 -n "Linux Kernel Image" \
4038 -d linux.bin.gz uImage
4041 The "mkimage" tool can also be used to create ramdisk images for use
4042 with U-Boot, either separated from the Linux kernel image, or
4043 combined into one file. "mkimage" encapsulates the images with a 64
4044 byte header containing information about target architecture,
4045 operating system, image type, compression method, entry points, time
4046 stamp, CRC32 checksums, etc.
4048 "mkimage" can be called in two ways: to verify existing images and
4049 print the header information, or to build new images.
4051 In the first form (with "-l" option) mkimage lists the information
4052 contained in the header of an existing U-Boot image; this includes
4053 checksum verification:
4055 tools/mkimage -l image
4056 -l ==> list image header information
4058 The second form (with "-d" option) is used to build a U-Boot image
4059 from a "data file" which is used as image payload:
4061 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4062 -n name -d data_file image
4063 -A ==> set architecture to 'arch'
4064 -O ==> set operating system to 'os'
4065 -T ==> set image type to 'type'
4066 -C ==> set compression type 'comp'
4067 -a ==> set load address to 'addr' (hex)
4068 -e ==> set entry point to 'ep' (hex)
4069 -n ==> set image name to 'name'
4070 -d ==> use image data from 'datafile'
4072 Right now, all Linux kernels for PowerPC systems use the same load
4073 address (0x00000000), but the entry point address depends on the
4076 - 2.2.x kernels have the entry point at 0x0000000C,
4077 - 2.3.x and later kernels have the entry point at 0x00000000.
4079 So a typical call to build a U-Boot image would read:
4081 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4082 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4083 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4084 > examples/uImage.TQM850L
4085 Image Name: 2.4.4 kernel for TQM850L
4086 Created: Wed Jul 19 02:34:59 2000
4087 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4088 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4089 Load Address: 0x00000000
4090 Entry Point: 0x00000000
4092 To verify the contents of the image (or check for corruption):
4094 -> tools/mkimage -l examples/uImage.TQM850L
4095 Image Name: 2.4.4 kernel for TQM850L
4096 Created: Wed Jul 19 02:34:59 2000
4097 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4098 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4099 Load Address: 0x00000000
4100 Entry Point: 0x00000000
4102 NOTE: for embedded systems where boot time is critical you can trade
4103 speed for memory and install an UNCOMPRESSED image instead: this
4104 needs more space in Flash, but boots much faster since it does not
4105 need to be uncompressed:
4107 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4108 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4109 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4110 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4111 > examples/uImage.TQM850L-uncompressed
4112 Image Name: 2.4.4 kernel for TQM850L
4113 Created: Wed Jul 19 02:34:59 2000
4114 Image Type: PowerPC Linux Kernel Image (uncompressed)
4115 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4116 Load Address: 0x00000000
4117 Entry Point: 0x00000000
4120 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4121 when your kernel is intended to use an initial ramdisk:
4123 -> tools/mkimage -n 'Simple Ramdisk Image' \
4124 > -A ppc -O linux -T ramdisk -C gzip \
4125 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4126 Image Name: Simple Ramdisk Image
4127 Created: Wed Jan 12 14:01:50 2000
4128 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4129 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4130 Load Address: 0x00000000
4131 Entry Point: 0x00000000
4134 Installing a Linux Image:
4135 -------------------------
4137 To downloading a U-Boot image over the serial (console) interface,
4138 you must convert the image to S-Record format:
4140 objcopy -I binary -O srec examples/image examples/image.srec
4142 The 'objcopy' does not understand the information in the U-Boot
4143 image header, so the resulting S-Record file will be relative to
4144 address 0x00000000. To load it to a given address, you need to
4145 specify the target address as 'offset' parameter with the 'loads'
4148 Example: install the image to address 0x40100000 (which on the
4149 TQM8xxL is in the first Flash bank):
4151 => erase 40100000 401FFFFF
4157 ## Ready for S-Record download ...
4158 ~>examples/image.srec
4159 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4161 15989 15990 15991 15992
4162 [file transfer complete]
4164 ## Start Addr = 0x00000000
4167 You can check the success of the download using the 'iminfo' command;
4168 this includes a checksum verification so you can be sure no data
4169 corruption happened:
4173 ## Checking Image at 40100000 ...
4174 Image Name: 2.2.13 for initrd on TQM850L
4175 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4176 Data Size: 335725 Bytes = 327 kB = 0 MB
4177 Load Address: 00000000
4178 Entry Point: 0000000c
4179 Verifying Checksum ... OK
4185 The "bootm" command is used to boot an application that is stored in
4186 memory (RAM or Flash). In case of a Linux kernel image, the contents
4187 of the "bootargs" environment variable is passed to the kernel as
4188 parameters. You can check and modify this variable using the
4189 "printenv" and "setenv" commands:
4192 => printenv bootargs
4193 bootargs=root=/dev/ram
4195 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4197 => printenv bootargs
4198 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4201 ## Booting Linux kernel at 40020000 ...
4202 Image Name: 2.2.13 for NFS on TQM850L
4203 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4204 Data Size: 381681 Bytes = 372 kB = 0 MB
4205 Load Address: 00000000
4206 Entry Point: 0000000c
4207 Verifying Checksum ... OK
4208 Uncompressing Kernel Image ... OK
4209 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
4210 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4211 time_init: decrementer frequency = 187500000/60
4212 Calibrating delay loop... 49.77 BogoMIPS
4213 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4216 If you want to boot a Linux kernel with initial RAM disk, you pass
4217 the memory addresses of both the kernel and the initrd image (PPBCOOT
4218 format!) to the "bootm" command:
4220 => imi 40100000 40200000
4222 ## Checking Image at 40100000 ...
4223 Image Name: 2.2.13 for initrd on TQM850L
4224 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4225 Data Size: 335725 Bytes = 327 kB = 0 MB
4226 Load Address: 00000000
4227 Entry Point: 0000000c
4228 Verifying Checksum ... OK
4230 ## Checking Image at 40200000 ...
4231 Image Name: Simple Ramdisk Image
4232 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4233 Data Size: 566530 Bytes = 553 kB = 0 MB
4234 Load Address: 00000000
4235 Entry Point: 00000000
4236 Verifying Checksum ... OK
4238 => bootm 40100000 40200000
4239 ## Booting Linux kernel at 40100000 ...
4240 Image Name: 2.2.13 for initrd on TQM850L
4241 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4242 Data Size: 335725 Bytes = 327 kB = 0 MB
4243 Load Address: 00000000
4244 Entry Point: 0000000c
4245 Verifying Checksum ... OK
4246 Uncompressing Kernel Image ... OK
4247 ## Loading RAMDisk Image at 40200000 ...
4248 Image Name: Simple Ramdisk Image
4249 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4250 Data Size: 566530 Bytes = 553 kB = 0 MB
4251 Load Address: 00000000
4252 Entry Point: 00000000
4253 Verifying Checksum ... OK
4254 Loading Ramdisk ... OK
4255 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
4256 Boot arguments: root=/dev/ram
4257 time_init: decrementer frequency = 187500000/60
4258 Calibrating delay loop... 49.77 BogoMIPS
4260 RAMDISK: Compressed image found at block 0
4261 VFS: Mounted root (ext2 filesystem).
4265 Boot Linux and pass a flat device tree:
4268 First, U-Boot must be compiled with the appropriate defines. See the section
4269 titled "Linux Kernel Interface" above for a more in depth explanation. The
4270 following is an example of how to start a kernel and pass an updated
4276 oft=oftrees/mpc8540ads.dtb
4277 => tftp $oftaddr $oft
4278 Speed: 1000, full duplex
4280 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4281 Filename 'oftrees/mpc8540ads.dtb'.
4282 Load address: 0x300000
4285 Bytes transferred = 4106 (100a hex)
4286 => tftp $loadaddr $bootfile
4287 Speed: 1000, full duplex
4289 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4291 Load address: 0x200000
4292 Loading:############
4294 Bytes transferred = 1029407 (fb51f hex)
4299 => bootm $loadaddr - $oftaddr
4300 ## Booting image at 00200000 ...
4301 Image Name: Linux-2.6.17-dirty
4302 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4303 Data Size: 1029343 Bytes = 1005.2 kB
4304 Load Address: 00000000
4305 Entry Point: 00000000
4306 Verifying Checksum ... OK
4307 Uncompressing Kernel Image ... OK
4308 Booting using flat device tree at 0x300000
4309 Using MPC85xx ADS machine description
4310 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4314 More About U-Boot Image Types:
4315 ------------------------------
4317 U-Boot supports the following image types:
4319 "Standalone Programs" are directly runnable in the environment
4320 provided by U-Boot; it is expected that (if they behave
4321 well) you can continue to work in U-Boot after return from
4322 the Standalone Program.
4323 "OS Kernel Images" are usually images of some Embedded OS which
4324 will take over control completely. Usually these programs
4325 will install their own set of exception handlers, device
4326 drivers, set up the MMU, etc. - this means, that you cannot
4327 expect to re-enter U-Boot except by resetting the CPU.
4328 "RAMDisk Images" are more or less just data blocks, and their
4329 parameters (address, size) are passed to an OS kernel that is
4331 "Multi-File Images" contain several images, typically an OS
4332 (Linux) kernel image and one or more data images like
4333 RAMDisks. This construct is useful for instance when you want
4334 to boot over the network using BOOTP etc., where the boot
4335 server provides just a single image file, but you want to get
4336 for instance an OS kernel and a RAMDisk image.
4338 "Multi-File Images" start with a list of image sizes, each
4339 image size (in bytes) specified by an "uint32_t" in network
4340 byte order. This list is terminated by an "(uint32_t)0".
4341 Immediately after the terminating 0 follow the images, one by
4342 one, all aligned on "uint32_t" boundaries (size rounded up to
4343 a multiple of 4 bytes).
4345 "Firmware Images" are binary images containing firmware (like
4346 U-Boot or FPGA images) which usually will be programmed to
4349 "Script files" are command sequences that will be executed by
4350 U-Boot's command interpreter; this feature is especially
4351 useful when you configure U-Boot to use a real shell (hush)
4352 as command interpreter.
4358 One of the features of U-Boot is that you can dynamically load and
4359 run "standalone" applications, which can use some resources of
4360 U-Boot like console I/O functions or interrupt services.
4362 Two simple examples are included with the sources:
4367 'examples/hello_world.c' contains a small "Hello World" Demo
4368 application; it is automatically compiled when you build U-Boot.
4369 It's configured to run at address 0x00040004, so you can play with it
4373 ## Ready for S-Record download ...
4374 ~>examples/hello_world.srec
4375 1 2 3 4 5 6 7 8 9 10 11 ...
4376 [file transfer complete]
4378 ## Start Addr = 0x00040004
4380 => go 40004 Hello World! This is a test.
4381 ## Starting application at 0x00040004 ...
4392 Hit any key to exit ...
4394 ## Application terminated, rc = 0x0
4396 Another example, which demonstrates how to register a CPM interrupt
4397 handler with the U-Boot code, can be found in 'examples/timer.c'.
4398 Here, a CPM timer is set up to generate an interrupt every second.
4399 The interrupt service routine is trivial, just printing a '.'
4400 character, but this is just a demo program. The application can be
4401 controlled by the following keys:
4403 ? - print current values og the CPM Timer registers
4404 b - enable interrupts and start timer
4405 e - stop timer and disable interrupts
4406 q - quit application
4409 ## Ready for S-Record download ...
4410 ~>examples/timer.srec
4411 1 2 3 4 5 6 7 8 9 10 11 ...
4412 [file transfer complete]
4414 ## Start Addr = 0x00040004
4417 ## Starting application at 0x00040004 ...
4420 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4423 [q, b, e, ?] Set interval 1000000 us
4426 [q, b, e, ?] ........
4427 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4430 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4433 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4436 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4438 [q, b, e, ?] ...Stopping timer
4440 [q, b, e, ?] ## Application terminated, rc = 0x0
4446 Over time, many people have reported problems when trying to use the
4447 "minicom" terminal emulation program for serial download. I (wd)
4448 consider minicom to be broken, and recommend not to use it. Under
4449 Unix, I recommend to use C-Kermit for general purpose use (and
4450 especially for kermit binary protocol download ("loadb" command), and
4451 use "cu" for S-Record download ("loads" command).
4453 Nevertheless, if you absolutely want to use it try adding this
4454 configuration to your "File transfer protocols" section:
4456 Name Program Name U/D FullScr IO-Red. Multi
4457 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4458 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4464 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4465 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4467 Building requires a cross environment; it is known to work on
4468 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4469 need gmake since the Makefiles are not compatible with BSD make).
4470 Note that the cross-powerpc package does not install include files;
4471 attempting to build U-Boot will fail because <machine/ansi.h> is
4472 missing. This file has to be installed and patched manually:
4474 # cd /usr/pkg/cross/powerpc-netbsd/include
4476 # ln -s powerpc machine
4477 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4478 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4480 Native builds *don't* work due to incompatibilities between native
4481 and U-Boot include files.
4483 Booting assumes that (the first part of) the image booted is a
4484 stage-2 loader which in turn loads and then invokes the kernel
4485 proper. Loader sources will eventually appear in the NetBSD source
4486 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4487 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4490 Implementation Internals:
4491 =========================
4493 The following is not intended to be a complete description of every
4494 implementation detail. However, it should help to understand the
4495 inner workings of U-Boot and make it easier to port it to custom
4499 Initial Stack, Global Data:
4500 ---------------------------
4502 The implementation of U-Boot is complicated by the fact that U-Boot
4503 starts running out of ROM (flash memory), usually without access to
4504 system RAM (because the memory controller is not initialized yet).
4505 This means that we don't have writable Data or BSS segments, and BSS
4506 is not initialized as zero. To be able to get a C environment working
4507 at all, we have to allocate at least a minimal stack. Implementation
4508 options for this are defined and restricted by the CPU used: Some CPU
4509 models provide on-chip memory (like the IMMR area on MPC8xx and
4510 MPC826x processors), on others (parts of) the data cache can be
4511 locked as (mis-) used as memory, etc.
4513 Chris Hallinan posted a good summary of these issues to the
4514 U-Boot mailing list:
4516 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4517 From: "Chris Hallinan" <clh@net1plus.com>
4518 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4521 Correct me if I'm wrong, folks, but the way I understand it
4522 is this: Using DCACHE as initial RAM for Stack, etc, does not
4523 require any physical RAM backing up the cache. The cleverness
4524 is that the cache is being used as a temporary supply of
4525 necessary storage before the SDRAM controller is setup. It's
4526 beyond the scope of this list to explain the details, but you
4527 can see how this works by studying the cache architecture and
4528 operation in the architecture and processor-specific manuals.
4530 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4531 is another option for the system designer to use as an
4532 initial stack/RAM area prior to SDRAM being available. Either
4533 option should work for you. Using CS 4 should be fine if your
4534 board designers haven't used it for something that would
4535 cause you grief during the initial boot! It is frequently not
4538 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4539 with your processor/board/system design. The default value
4540 you will find in any recent u-boot distribution in
4541 walnut.h should work for you. I'd set it to a value larger
4542 than your SDRAM module. If you have a 64MB SDRAM module, set
4543 it above 400_0000. Just make sure your board has no resources
4544 that are supposed to respond to that address! That code in
4545 start.S has been around a while and should work as is when
4546 you get the config right.
4551 It is essential to remember this, since it has some impact on the C
4552 code for the initialization procedures:
4554 * Initialized global data (data segment) is read-only. Do not attempt
4557 * Do not use any uninitialized global data (or implicitely initialized
4558 as zero data - BSS segment) at all - this is undefined, initiali-
4559 zation is performed later (when relocating to RAM).
4561 * Stack space is very limited. Avoid big data buffers or things like
4564 Having only the stack as writable memory limits means we cannot use
4565 normal global data to share information beween the code. But it
4566 turned out that the implementation of U-Boot can be greatly
4567 simplified by making a global data structure (gd_t) available to all
4568 functions. We could pass a pointer to this data as argument to _all_
4569 functions, but this would bloat the code. Instead we use a feature of
4570 the GCC compiler (Global Register Variables) to share the data: we
4571 place a pointer (gd) to the global data into a register which we
4572 reserve for this purpose.
4574 When choosing a register for such a purpose we are restricted by the
4575 relevant (E)ABI specifications for the current architecture, and by
4576 GCC's implementation.
4578 For PowerPC, the following registers have specific use:
4580 R2: reserved for system use
4581 R3-R4: parameter passing and return values
4582 R5-R10: parameter passing
4583 R13: small data area pointer
4587 (U-Boot also uses R12 as internal GOT pointer. r12
4588 is a volatile register so r12 needs to be reset when
4589 going back and forth between asm and C)
4591 ==> U-Boot will use R2 to hold a pointer to the global data
4593 Note: on PPC, we could use a static initializer (since the
4594 address of the global data structure is known at compile time),
4595 but it turned out that reserving a register results in somewhat
4596 smaller code - although the code savings are not that big (on
4597 average for all boards 752 bytes for the whole U-Boot image,
4598 624 text + 127 data).
4600 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4601 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4603 ==> U-Boot will use P3 to hold a pointer to the global data
4605 On ARM, the following registers are used:
4607 R0: function argument word/integer result
4608 R1-R3: function argument word
4610 R10: stack limit (used only if stack checking if enabled)
4611 R11: argument (frame) pointer
4612 R12: temporary workspace
4615 R15: program counter
4617 ==> U-Boot will use R8 to hold a pointer to the global data
4619 On Nios II, the ABI is documented here:
4620 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4622 ==> U-Boot will use gp to hold a pointer to the global data
4624 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4625 to access small data sections, so gp is free.
4627 On NDS32, the following registers are used:
4629 R0-R1: argument/return
4631 R15: temporary register for assembler
4632 R16: trampoline register
4633 R28: frame pointer (FP)
4634 R29: global pointer (GP)
4635 R30: link register (LP)
4636 R31: stack pointer (SP)
4637 PC: program counter (PC)
4639 ==> U-Boot will use R10 to hold a pointer to the global data
4641 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4642 or current versions of GCC may "optimize" the code too much.
4647 U-Boot runs in system state and uses physical addresses, i.e. the
4648 MMU is not used either for address mapping nor for memory protection.
4650 The available memory is mapped to fixed addresses using the memory
4651 controller. In this process, a contiguous block is formed for each
4652 memory type (Flash, SDRAM, SRAM), even when it consists of several
4653 physical memory banks.
4655 U-Boot is installed in the first 128 kB of the first Flash bank (on
4656 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4657 booting and sizing and initializing DRAM, the code relocates itself
4658 to the upper end of DRAM. Immediately below the U-Boot code some
4659 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4660 configuration setting]. Below that, a structure with global Board
4661 Info data is placed, followed by the stack (growing downward).
4663 Additionally, some exception handler code is copied to the low 8 kB
4664 of DRAM (0x00000000 ... 0x00001FFF).
4666 So a typical memory configuration with 16 MB of DRAM could look like
4669 0x0000 0000 Exception Vector code
4672 0x0000 2000 Free for Application Use
4678 0x00FB FF20 Monitor Stack (Growing downward)
4679 0x00FB FFAC Board Info Data and permanent copy of global data
4680 0x00FC 0000 Malloc Arena
4683 0x00FE 0000 RAM Copy of Monitor Code
4684 ... eventually: LCD or video framebuffer
4685 ... eventually: pRAM (Protected RAM - unchanged by reset)
4686 0x00FF FFFF [End of RAM]
4689 System Initialization:
4690 ----------------------
4692 In the reset configuration, U-Boot starts at the reset entry point
4693 (on most PowerPC systems at address 0x00000100). Because of the reset
4694 configuration for CS0# this is a mirror of the onboard Flash memory.
4695 To be able to re-map memory U-Boot then jumps to its link address.
4696 To be able to implement the initialization code in C, a (small!)
4697 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4698 which provide such a feature like MPC8xx or MPC8260), or in a locked
4699 part of the data cache. After that, U-Boot initializes the CPU core,
4700 the caches and the SIU.
4702 Next, all (potentially) available memory banks are mapped using a
4703 preliminary mapping. For example, we put them on 512 MB boundaries
4704 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4705 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4706 programmed for SDRAM access. Using the temporary configuration, a
4707 simple memory test is run that determines the size of the SDRAM
4710 When there is more than one SDRAM bank, and the banks are of
4711 different size, the largest is mapped first. For equal size, the first
4712 bank (CS2#) is mapped first. The first mapping is always for address
4713 0x00000000, with any additional banks following immediately to create
4714 contiguous memory starting from 0.
4716 Then, the monitor installs itself at the upper end of the SDRAM area
4717 and allocates memory for use by malloc() and for the global Board
4718 Info data; also, the exception vector code is copied to the low RAM
4719 pages, and the final stack is set up.
4721 Only after this relocation will you have a "normal" C environment;
4722 until that you are restricted in several ways, mostly because you are
4723 running from ROM, and because the code will have to be relocated to a
4727 U-Boot Porting Guide:
4728 ----------------------
4730 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4734 int main(int argc, char *argv[])
4736 sighandler_t no_more_time;
4738 signal(SIGALRM, no_more_time);
4739 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4741 if (available_money > available_manpower) {
4742 Pay consultant to port U-Boot;
4746 Download latest U-Boot source;
4748 Subscribe to u-boot mailing list;
4751 email("Hi, I am new to U-Boot, how do I get started?");
4754 Read the README file in the top level directory;
4755 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4756 Read applicable doc/*.README;
4757 Read the source, Luke;
4758 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4761 if (available_money > toLocalCurrency ($2500))
4764 Add a lot of aggravation and time;
4766 if (a similar board exists) { /* hopefully... */
4767 cp -a board/<similar> board/<myboard>
4768 cp include/configs/<similar>.h include/configs/<myboard>.h
4770 Create your own board support subdirectory;
4771 Create your own board include/configs/<myboard>.h file;
4773 Edit new board/<myboard> files
4774 Edit new include/configs/<myboard>.h
4779 Add / modify source code;
4783 email("Hi, I am having problems...");
4785 Send patch file to the U-Boot email list;
4786 if (reasonable critiques)
4787 Incorporate improvements from email list code review;
4789 Defend code as written;
4795 void no_more_time (int sig)
4804 All contributions to U-Boot should conform to the Linux kernel
4805 coding style; see the file "Documentation/CodingStyle" and the script
4806 "scripts/Lindent" in your Linux kernel source directory.
4808 Source files originating from a different project (for example the
4809 MTD subsystem) are generally exempt from these guidelines and are not
4810 reformated to ease subsequent migration to newer versions of those
4813 Please note that U-Boot is implemented in C (and to some small parts in
4814 Assembler); no C++ is used, so please do not use C++ style comments (//)
4817 Please also stick to the following formatting rules:
4818 - remove any trailing white space
4819 - use TAB characters for indentation and vertical alignment, not spaces
4820 - make sure NOT to use DOS '\r\n' line feeds
4821 - do not add more than 2 consecutive empty lines to source files
4822 - do not add trailing empty lines to source files
4824 Submissions which do not conform to the standards may be returned
4825 with a request to reformat the changes.
4831 Since the number of patches for U-Boot is growing, we need to
4832 establish some rules. Submissions which do not conform to these rules
4833 may be rejected, even when they contain important and valuable stuff.
4835 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4837 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4838 see http://lists.denx.de/mailman/listinfo/u-boot
4840 When you send a patch, please include the following information with
4843 * For bug fixes: a description of the bug and how your patch fixes
4844 this bug. Please try to include a way of demonstrating that the
4845 patch actually fixes something.
4847 * For new features: a description of the feature and your
4850 * A CHANGELOG entry as plaintext (separate from the patch)
4852 * For major contributions, your entry to the CREDITS file
4854 * When you add support for a new board, don't forget to add this
4855 board to the MAINTAINERS file, too.
4857 * If your patch adds new configuration options, don't forget to
4858 document these in the README file.
4860 * The patch itself. If you are using git (which is *strongly*
4861 recommended) you can easily generate the patch using the
4862 "git format-patch". If you then use "git send-email" to send it to
4863 the U-Boot mailing list, you will avoid most of the common problems
4864 with some other mail clients.
4866 If you cannot use git, use "diff -purN OLD NEW". If your version of
4867 diff does not support these options, then get the latest version of
4870 The current directory when running this command shall be the parent
4871 directory of the U-Boot source tree (i. e. please make sure that
4872 your patch includes sufficient directory information for the
4875 We prefer patches as plain text. MIME attachments are discouraged,
4876 and compressed attachments must not be used.
4878 * If one logical set of modifications affects or creates several
4879 files, all these changes shall be submitted in a SINGLE patch file.
4881 * Changesets that contain different, unrelated modifications shall be
4882 submitted as SEPARATE patches, one patch per changeset.
4887 * Before sending the patch, run the MAKEALL script on your patched
4888 source tree and make sure that no errors or warnings are reported
4889 for any of the boards.
4891 * Keep your modifications to the necessary minimum: A patch
4892 containing several unrelated changes or arbitrary reformats will be
4893 returned with a request to re-formatting / split it.
4895 * If you modify existing code, make sure that your new code does not
4896 add to the memory footprint of the code ;-) Small is beautiful!
4897 When adding new features, these should compile conditionally only
4898 (using #ifdef), and the resulting code with the new feature
4899 disabled must not need more memory than the old code without your
4902 * Remember that there is a size limit of 100 kB per message on the
4903 u-boot mailing list. Bigger patches will be moderated. If they are
4904 reasonable and not too big, they will be acknowledged. But patches
4905 bigger than the size limit should be avoided.