2 # (C) Copyright 2000 - 2011
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 - Boot Delay: CONFIG_BOOTDELAY - in seconds
659 Delay before automatically booting the default image;
660 set to -1 to disable autoboot.
662 See doc/README.autoboot for these options that
663 work with CONFIG_BOOTDELAY. None are required.
664 CONFIG_BOOT_RETRY_TIME
665 CONFIG_BOOT_RETRY_MIN
666 CONFIG_AUTOBOOT_KEYED
667 CONFIG_AUTOBOOT_PROMPT
668 CONFIG_AUTOBOOT_DELAY_STR
669 CONFIG_AUTOBOOT_STOP_STR
670 CONFIG_AUTOBOOT_DELAY_STR2
671 CONFIG_AUTOBOOT_STOP_STR2
672 CONFIG_ZERO_BOOTDELAY_CHECK
673 CONFIG_RESET_TO_RETRY
677 Only needed when CONFIG_BOOTDELAY is enabled;
678 define a command string that is automatically executed
679 when no character is read on the console interface
680 within "Boot Delay" after reset.
683 This can be used to pass arguments to the bootm
684 command. The value of CONFIG_BOOTARGS goes into the
685 environment value "bootargs".
687 CONFIG_RAMBOOT and CONFIG_NFSBOOT
688 The value of these goes into the environment as
689 "ramboot" and "nfsboot" respectively, and can be used
690 as a convenience, when switching between booting from
696 When this option is #defined, the existence of the
697 environment variable "preboot" will be checked
698 immediately before starting the CONFIG_BOOTDELAY
699 countdown and/or running the auto-boot command resp.
700 entering interactive mode.
702 This feature is especially useful when "preboot" is
703 automatically generated or modified. For an example
704 see the LWMON board specific code: here "preboot" is
705 modified when the user holds down a certain
706 combination of keys on the (special) keyboard when
709 - Serial Download Echo Mode:
711 If defined to 1, all characters received during a
712 serial download (using the "loads" command) are
713 echoed back. This might be needed by some terminal
714 emulations (like "cu"), but may as well just take
715 time on others. This setting #define's the initial
716 value of the "loads_echo" environment variable.
718 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
720 Select one of the baudrates listed in
721 CONFIG_SYS_BAUDRATE_TABLE, see below.
724 Monitor commands can be included or excluded
725 from the build by using the #include files
726 "config_cmd_all.h" and #undef'ing unwanted
727 commands, or using "config_cmd_default.h"
728 and augmenting with additional #define's
731 The default command configuration includes all commands
732 except those marked below with a "*".
734 CONFIG_CMD_ASKENV * ask for env variable
735 CONFIG_CMD_BDI bdinfo
736 CONFIG_CMD_BEDBUG * Include BedBug Debugger
737 CONFIG_CMD_BMP * BMP support
738 CONFIG_CMD_BSP * Board specific commands
739 CONFIG_CMD_BOOTD bootd
740 CONFIG_CMD_CACHE * icache, dcache
741 CONFIG_CMD_CONSOLE coninfo
742 CONFIG_CMD_CRC32 * crc32
743 CONFIG_CMD_DATE * support for RTC, date/time...
744 CONFIG_CMD_DHCP * DHCP support
745 CONFIG_CMD_DIAG * Diagnostics
746 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
747 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
748 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
749 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
750 CONFIG_CMD_DTT * Digital Therm and Thermostat
751 CONFIG_CMD_ECHO echo arguments
752 CONFIG_CMD_EDITENV edit env variable
753 CONFIG_CMD_EEPROM * EEPROM read/write support
754 CONFIG_CMD_ELF * bootelf, bootvx
755 CONFIG_CMD_EXPORTENV * export the environment
756 CONFIG_CMD_SAVEENV saveenv
757 CONFIG_CMD_FDC * Floppy Disk Support
758 CONFIG_CMD_FAT * FAT partition support
759 CONFIG_CMD_FDOS * Dos diskette Support
760 CONFIG_CMD_FLASH flinfo, erase, protect
761 CONFIG_CMD_FPGA FPGA device initialization support
762 CONFIG_CMD_GO * the 'go' command (exec code)
763 CONFIG_CMD_GREPENV * search environment
764 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
765 CONFIG_CMD_I2C * I2C serial bus support
766 CONFIG_CMD_IDE * IDE harddisk support
767 CONFIG_CMD_IMI iminfo
768 CONFIG_CMD_IMLS List all found images
769 CONFIG_CMD_IMMAP * IMMR dump support
770 CONFIG_CMD_IMPORTENV * import an environment
771 CONFIG_CMD_IRQ * irqinfo
772 CONFIG_CMD_ITEST Integer/string test of 2 values
773 CONFIG_CMD_JFFS2 * JFFS2 Support
774 CONFIG_CMD_KGDB * kgdb
775 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
776 CONFIG_CMD_LOADB loadb
777 CONFIG_CMD_LOADS loads
778 CONFIG_CMD_MD5SUM print md5 message digest
779 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
780 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
782 CONFIG_CMD_MISC Misc functions like sleep etc
783 CONFIG_CMD_MMC * MMC memory mapped support
784 CONFIG_CMD_MII * MII utility commands
785 CONFIG_CMD_MTDPARTS * MTD partition support
786 CONFIG_CMD_NAND * NAND support
787 CONFIG_CMD_NET bootp, tftpboot, rarpboot
788 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
789 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
790 CONFIG_CMD_PCI * pciinfo
791 CONFIG_CMD_PCMCIA * PCMCIA support
792 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
794 CONFIG_CMD_PORTIO * Port I/O
795 CONFIG_CMD_REGINFO * Register dump
796 CONFIG_CMD_RUN run command in env variable
797 CONFIG_CMD_SAVES * save S record dump
798 CONFIG_CMD_SCSI * SCSI Support
799 CONFIG_CMD_SDRAM * print SDRAM configuration information
800 (requires CONFIG_CMD_I2C)
801 CONFIG_CMD_SETGETDCR Support for DCR Register access
803 CONFIG_CMD_SHA1SUM print sha1 memory digest
804 (requires CONFIG_CMD_MEMORY)
805 CONFIG_CMD_SOURCE "source" command Support
806 CONFIG_CMD_SPI * SPI serial bus support
807 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
808 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
809 CONFIG_CMD_TIME * run command and report execution time
810 CONFIG_CMD_USB * USB support
811 CONFIG_CMD_CDP * Cisco Discover Protocol support
812 CONFIG_CMD_FSL * Microblaze FSL support
815 EXAMPLE: If you want all functions except of network
816 support you can write:
818 #include "config_cmd_all.h"
819 #undef CONFIG_CMD_NET
822 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
824 Note: Don't enable the "icache" and "dcache" commands
825 (configuration option CONFIG_CMD_CACHE) unless you know
826 what you (and your U-Boot users) are doing. Data
827 cache cannot be enabled on systems like the 8xx or
828 8260 (where accesses to the IMMR region must be
829 uncached), and it cannot be disabled on all other
830 systems where we (mis-) use the data cache to hold an
831 initial stack and some data.
834 XXX - this list needs to get updated!
838 If this variable is defined, U-Boot will use a device tree
839 to configure its devices, instead of relying on statically
840 compiled #defines in the board file. This option is
841 experimental and only available on a few boards. The device
842 tree is available in the global data as gd->fdt_blob.
844 U-Boot needs to get its device tree from somewhere. This can
845 be done using one of the two options below:
848 If this variable is defined, U-Boot will embed a device tree
849 binary in its image. This device tree file should be in the
850 board directory and called <soc>-<board>.dts. The binary file
851 is then picked up in board_init_f() and made available through
852 the global data structure as gd->blob.
855 If this variable is defined, U-Boot will build a device tree
856 binary. It will be called u-boot.dtb. Architecture-specific
857 code will locate it at run-time. Generally this works by:
859 cat u-boot.bin u-boot.dtb >image.bin
861 and in fact, U-Boot does this for you, creating a file called
862 u-boot-dtb.bin which is useful in the common case. You can
863 still use the individual files if you need something more
868 If this variable is defined, it enables watchdog
869 support for the SoC. There must be support in the SoC
870 specific code for a watchdog. For the 8xx and 8260
871 CPUs, the SIU Watchdog feature is enabled in the SYPCR
872 register. When supported for a specific SoC is
873 available, then no further board specific code should
877 When using a watchdog circuitry external to the used
878 SoC, then define this variable and provide board
879 specific code for the "hw_watchdog_reset" function.
882 CONFIG_VERSION_VARIABLE
883 If this variable is defined, an environment variable
884 named "ver" is created by U-Boot showing the U-Boot
885 version as printed by the "version" command.
886 This variable is readonly.
890 When CONFIG_CMD_DATE is selected, the type of the RTC
891 has to be selected, too. Define exactly one of the
894 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
895 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
896 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
897 CONFIG_RTC_MC146818 - use MC146818 RTC
898 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
899 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
900 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
901 CONFIG_RTC_DS164x - use Dallas DS164x RTC
902 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
903 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
904 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
905 CONFIG_SYS_RV3029_TCR - enable trickle charger on
908 Note that if the RTC uses I2C, then the I2C interface
909 must also be configured. See I2C Support, below.
912 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
913 CONFIG_PCA953X_INFO - enable pca953x info command
915 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
916 chip-ngpio pairs that tell the PCA953X driver the number of
917 pins supported by a particular chip.
919 Note that if the GPIO device uses I2C, then the I2C interface
920 must also be configured. See I2C Support, below.
924 When CONFIG_TIMESTAMP is selected, the timestamp
925 (date and time) of an image is printed by image
926 commands like bootm or iminfo. This option is
927 automatically enabled when you select CONFIG_CMD_DATE .
930 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
931 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
933 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
934 CONFIG_CMD_SCSI) you must configure support for at
935 least one partition type as well.
938 CONFIG_IDE_RESET_ROUTINE - this is defined in several
939 board configurations files but used nowhere!
941 CONFIG_IDE_RESET - is this is defined, IDE Reset will
942 be performed by calling the function
943 ide_set_reset(int reset)
944 which has to be defined in a board specific file
949 Set this to enable ATAPI support.
954 Set this to enable support for disks larger than 137GB
955 Also look at CONFIG_SYS_64BIT_LBA.
956 Whithout these , LBA48 support uses 32bit variables and will 'only'
957 support disks up to 2.1TB.
959 CONFIG_SYS_64BIT_LBA:
960 When enabled, makes the IDE subsystem use 64bit sector addresses.
964 At the moment only there is only support for the
965 SYM53C8XX SCSI controller; define
966 CONFIG_SCSI_SYM53C8XX to enable it.
968 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
969 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
970 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
971 maximum numbers of LUNs, SCSI ID's and target
973 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
975 - NETWORK Support (PCI):
977 Support for Intel 8254x/8257x gigabit chips.
980 Utility code for direct access to the SPI bus on Intel 8257x.
981 This does not do anything useful unless you set at least one
982 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
984 CONFIG_E1000_SPI_GENERIC
985 Allow generic access to the SPI bus on the Intel 8257x, for
986 example with the "sspi" command.
989 Management command for E1000 devices. When used on devices
990 with SPI support you can reprogram the EEPROM from U-Boot.
992 CONFIG_E1000_FALLBACK_MAC
993 default MAC for empty EEPROM after production.
996 Support for Intel 82557/82559/82559ER chips.
997 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
998 write routine for first time initialisation.
1001 Support for Digital 2114x chips.
1002 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1003 modem chip initialisation (KS8761/QS6611).
1006 Support for National dp83815 chips.
1009 Support for National dp8382[01] gigabit chips.
1011 - NETWORK Support (other):
1013 CONFIG_DRIVER_AT91EMAC
1014 Support for AT91RM9200 EMAC.
1017 Define this to use reduced MII inteface
1019 CONFIG_DRIVER_AT91EMAC_QUIET
1020 If this defined, the driver is quiet.
1021 The driver doen't show link status messages.
1023 CONFIG_DRIVER_LAN91C96
1024 Support for SMSC's LAN91C96 chips.
1026 CONFIG_LAN91C96_BASE
1027 Define this to hold the physical address
1028 of the LAN91C96's I/O space
1030 CONFIG_LAN91C96_USE_32_BIT
1031 Define this to enable 32 bit addressing
1033 CONFIG_DRIVER_SMC91111
1034 Support for SMSC's LAN91C111 chip
1036 CONFIG_SMC91111_BASE
1037 Define this to hold the physical address
1038 of the device (I/O space)
1040 CONFIG_SMC_USE_32_BIT
1041 Define this if data bus is 32 bits
1043 CONFIG_SMC_USE_IOFUNCS
1044 Define this to use i/o functions instead of macros
1045 (some hardware wont work with macros)
1047 CONFIG_DRIVER_TI_EMAC
1048 Support for davinci emac
1050 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1051 Define this if you have more then 3 PHYs.
1054 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1056 CONFIG_FTGMAC100_EGIGA
1057 Define this to use GE link update with gigabit PHY.
1058 Define this if FTGMAC100 is connected to gigabit PHY.
1059 If your system has 10/100 PHY only, it might not occur
1060 wrong behavior. Because PHY usually return timeout or
1061 useless data when polling gigabit status and gigabit
1062 control registers. This behavior won't affect the
1063 correctnessof 10/100 link speed update.
1066 Support for SMSC's LAN911x and LAN921x chips
1069 Define this to hold the physical address
1070 of the device (I/O space)
1072 CONFIG_SMC911X_32_BIT
1073 Define this if data bus is 32 bits
1075 CONFIG_SMC911X_16_BIT
1076 Define this if data bus is 16 bits. If your processor
1077 automatically converts one 32 bit word to two 16 bit
1078 words you may also try CONFIG_SMC911X_32_BIT.
1081 Support for Renesas on-chip Ethernet controller
1083 CONFIG_SH_ETHER_USE_PORT
1084 Define the number of ports to be used
1086 CONFIG_SH_ETHER_PHY_ADDR
1087 Define the ETH PHY's address
1089 CONFIG_SH_ETHER_CACHE_WRITEBACK
1090 If this option is set, the driver enables cache flush.
1093 CONFIG_GENERIC_LPC_TPM
1094 Support for generic parallel port TPM devices. Only one device
1095 per system is supported at this time.
1097 CONFIG_TPM_TIS_BASE_ADDRESS
1098 Base address where the generic TPM device is mapped
1099 to. Contemporary x86 systems usually map it at
1103 At the moment only the UHCI host controller is
1104 supported (PIP405, MIP405, MPC5200); define
1105 CONFIG_USB_UHCI to enable it.
1106 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1107 and define CONFIG_USB_STORAGE to enable the USB
1110 Supported are USB Keyboards and USB Floppy drives
1112 MPC5200 USB requires additional defines:
1114 for 528 MHz Clock: 0x0001bbbb
1118 for differential drivers: 0x00001000
1119 for single ended drivers: 0x00005000
1120 for differential drivers on PSC3: 0x00000100
1121 for single ended drivers on PSC3: 0x00004100
1122 CONFIG_SYS_USB_EVENT_POLL
1123 May be defined to allow interrupt polling
1124 instead of using asynchronous interrupts
1127 Define the below if you wish to use the USB console.
1128 Once firmware is rebuilt from a serial console issue the
1129 command "setenv stdin usbtty; setenv stdout usbtty" and
1130 attach your USB cable. The Unix command "dmesg" should print
1131 it has found a new device. The environment variable usbtty
1132 can be set to gserial or cdc_acm to enable your device to
1133 appear to a USB host as a Linux gserial device or a
1134 Common Device Class Abstract Control Model serial device.
1135 If you select usbtty = gserial you should be able to enumerate
1137 # modprobe usbserial vendor=0xVendorID product=0xProductID
1138 else if using cdc_acm, simply setting the environment
1139 variable usbtty to be cdc_acm should suffice. The following
1140 might be defined in YourBoardName.h
1143 Define this to build a UDC device
1146 Define this to have a tty type of device available to
1147 talk to the UDC device
1149 CONFIG_SYS_CONSOLE_IS_IN_ENV
1150 Define this if you want stdin, stdout &/or stderr to
1154 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1155 Derive USB clock from external clock "blah"
1156 - CONFIG_SYS_USB_EXTC_CLK 0x02
1158 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1159 Derive USB clock from brgclk
1160 - CONFIG_SYS_USB_BRG_CLK 0x04
1162 If you have a USB-IF assigned VendorID then you may wish to
1163 define your own vendor specific values either in BoardName.h
1164 or directly in usbd_vendor_info.h. If you don't define
1165 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1166 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1167 should pretend to be a Linux device to it's target host.
1169 CONFIG_USBD_MANUFACTURER
1170 Define this string as the name of your company for
1171 - CONFIG_USBD_MANUFACTURER "my company"
1173 CONFIG_USBD_PRODUCT_NAME
1174 Define this string as the name of your product
1175 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1177 CONFIG_USBD_VENDORID
1178 Define this as your assigned Vendor ID from the USB
1179 Implementors Forum. This *must* be a genuine Vendor ID
1180 to avoid polluting the USB namespace.
1181 - CONFIG_USBD_VENDORID 0xFFFF
1183 CONFIG_USBD_PRODUCTID
1184 Define this as the unique Product ID
1186 - CONFIG_USBD_PRODUCTID 0xFFFF
1188 - ULPI Layer Support:
1189 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1190 the generic ULPI layer. The generic layer accesses the ULPI PHY
1191 via the platform viewport, so you need both the genric layer and
1192 the viewport enabled. Currently only Chipidea/ARC based
1193 viewport is supported.
1194 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1195 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1198 The MMC controller on the Intel PXA is supported. To
1199 enable this define CONFIG_MMC. The MMC can be
1200 accessed from the boot prompt by mapping the device
1201 to physical memory similar to flash. Command line is
1202 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1203 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1206 Support for Renesas on-chip MMCIF controller
1208 CONFIG_SH_MMCIF_ADDR
1209 Define the base address of MMCIF registers
1212 Define the clock frequency for MMCIF
1214 - Journaling Flash filesystem support:
1215 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1216 CONFIG_JFFS2_NAND_DEV
1217 Define these for a default partition on a NAND device
1219 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1220 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1221 Define these for a default partition on a NOR device
1223 CONFIG_SYS_JFFS_CUSTOM_PART
1224 Define this to create an own partition. You have to provide a
1225 function struct part_info* jffs2_part_info(int part_num)
1227 If you define only one JFFS2 partition you may also want to
1228 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1229 to disable the command chpart. This is the default when you
1230 have not defined a custom partition
1232 - FAT(File Allocation Table) filesystem write function support:
1234 Support for saving memory data as a file
1235 in FAT formatted partition
1240 Define this to enable standard (PC-Style) keyboard
1244 Standard PC keyboard driver with US (is default) and
1245 GERMAN key layout (switch via environment 'keymap=de') support.
1246 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1247 for cfb_console. Supports cursor blinking.
1252 Define this to enable video support (for output to
1255 CONFIG_VIDEO_CT69000
1257 Enable Chips & Technologies 69000 Video chip
1259 CONFIG_VIDEO_SMI_LYNXEM
1260 Enable Silicon Motion SMI 712/710/810 Video chip. The
1261 video output is selected via environment 'videoout'
1262 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1265 For the CT69000 and SMI_LYNXEM drivers, videomode is
1266 selected via environment 'videomode'. Two different ways
1268 - "videomode=num" 'num' is a standard LiLo mode numbers.
1269 Following standard modes are supported (* is default):
1271 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1272 -------------+---------------------------------------------
1273 8 bits | 0x301* 0x303 0x305 0x161 0x307
1274 15 bits | 0x310 0x313 0x316 0x162 0x319
1275 16 bits | 0x311 0x314 0x317 0x163 0x31A
1276 24 bits | 0x312 0x315 0x318 ? 0x31B
1277 -------------+---------------------------------------------
1278 (i.e. setenv videomode 317; saveenv; reset;)
1280 - "videomode=bootargs" all the video parameters are parsed
1281 from the bootargs. (See drivers/video/videomodes.c)
1284 CONFIG_VIDEO_SED13806
1285 Enable Epson SED13806 driver. This driver supports 8bpp
1286 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1287 or CONFIG_VIDEO_SED13806_16BPP
1290 Enable the Freescale DIU video driver. Reference boards for
1291 SOCs that have a DIU should define this macro to enable DIU
1292 support, and should also define these other macros:
1298 CONFIG_VIDEO_SW_CURSOR
1299 CONFIG_VGA_AS_SINGLE_DEVICE
1301 CONFIG_VIDEO_BMP_LOGO
1303 The DIU driver will look for the 'video-mode' environment
1304 variable, and if defined, enable the DIU as a console during
1305 boot. See the documentation file README.video for a
1306 description of this variable.
1311 Define this to enable a custom keyboard support.
1312 This simply calls drv_keyboard_init() which must be
1313 defined in your board-specific files.
1314 The only board using this so far is RBC823.
1316 - LCD Support: CONFIG_LCD
1318 Define this to enable LCD support (for output to LCD
1319 display); also select one of the supported displays
1320 by defining one of these:
1324 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1326 CONFIG_NEC_NL6448AC33:
1328 NEC NL6448AC33-18. Active, color, single scan.
1330 CONFIG_NEC_NL6448BC20
1332 NEC NL6448BC20-08. 6.5", 640x480.
1333 Active, color, single scan.
1335 CONFIG_NEC_NL6448BC33_54
1337 NEC NL6448BC33-54. 10.4", 640x480.
1338 Active, color, single scan.
1342 Sharp 320x240. Active, color, single scan.
1343 It isn't 16x9, and I am not sure what it is.
1345 CONFIG_SHARP_LQ64D341
1347 Sharp LQ64D341 display, 640x480.
1348 Active, color, single scan.
1352 HLD1045 display, 640x480.
1353 Active, color, single scan.
1357 Optrex CBL50840-2 NF-FW 99 22 M5
1359 Hitachi LMG6912RPFC-00T
1363 320x240. Black & white.
1365 Normally display is black on white background; define
1366 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1368 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1370 If this option is set, the environment is checked for
1371 a variable "splashimage". If found, the usual display
1372 of logo, copyright and system information on the LCD
1373 is suppressed and the BMP image at the address
1374 specified in "splashimage" is loaded instead. The
1375 console is redirected to the "nulldev", too. This
1376 allows for a "silent" boot where a splash screen is
1377 loaded very quickly after power-on.
1379 CONFIG_SPLASH_SCREEN_ALIGN
1381 If this option is set the splash image can be freely positioned
1382 on the screen. Environment variable "splashpos" specifies the
1383 position as "x,y". If a positive number is given it is used as
1384 number of pixel from left/top. If a negative number is given it
1385 is used as number of pixel from right/bottom. You can also
1386 specify 'm' for centering the image.
1389 setenv splashpos m,m
1390 => image at center of screen
1392 setenv splashpos 30,20
1393 => image at x = 30 and y = 20
1395 setenv splashpos -10,m
1396 => vertically centered image
1397 at x = dspWidth - bmpWidth - 9
1399 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1401 If this option is set, additionally to standard BMP
1402 images, gzipped BMP images can be displayed via the
1403 splashscreen support or the bmp command.
1405 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1407 If this option is set, 8-bit RLE compressed BMP images
1408 can be displayed via the splashscreen support or the
1411 - Compression support:
1414 If this option is set, support for bzip2 compressed
1415 images is included. If not, only uncompressed and gzip
1416 compressed images are supported.
1418 NOTE: the bzip2 algorithm requires a lot of RAM, so
1419 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1424 If this option is set, support for lzma compressed
1427 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1428 requires an amount of dynamic memory that is given by the
1431 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1433 Where lc and lp stand for, respectively, Literal context bits
1434 and Literal pos bits.
1436 This value is upper-bounded by 14MB in the worst case. Anyway,
1437 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1438 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1439 a very small buffer.
1441 Use the lzmainfo tool to determinate the lc and lp values and
1442 then calculate the amount of needed dynamic memory (ensuring
1443 the appropriate CONFIG_SYS_MALLOC_LEN value).
1448 The address of PHY on MII bus.
1450 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1452 The clock frequency of the MII bus
1456 If this option is set, support for speed/duplex
1457 detection of gigabit PHY is included.
1459 CONFIG_PHY_RESET_DELAY
1461 Some PHY like Intel LXT971A need extra delay after
1462 reset before any MII register access is possible.
1463 For such PHY, set this option to the usec delay
1464 required. (minimum 300usec for LXT971A)
1466 CONFIG_PHY_CMD_DELAY (ppc4xx)
1468 Some PHY like Intel LXT971A need extra delay after
1469 command issued before MII status register can be read
1479 Define a default value for Ethernet address to use
1480 for the respective Ethernet interface, in case this
1481 is not determined automatically.
1486 Define a default value for the IP address to use for
1487 the default Ethernet interface, in case this is not
1488 determined through e.g. bootp.
1489 (Environment variable "ipaddr")
1491 - Server IP address:
1494 Defines a default value for the IP address of a TFTP
1495 server to contact when using the "tftboot" command.
1496 (Environment variable "serverip")
1498 CONFIG_KEEP_SERVERADDR
1500 Keeps the server's MAC address, in the env 'serveraddr'
1501 for passing to bootargs (like Linux's netconsole option)
1503 - Gateway IP address:
1506 Defines a default value for the IP address of the
1507 default router where packets to other networks are
1509 (Environment variable "gatewayip")
1514 Defines a default value for the subnet mask (or
1515 routing prefix) which is used to determine if an IP
1516 address belongs to the local subnet or needs to be
1517 forwarded through a router.
1518 (Environment variable "netmask")
1520 - Multicast TFTP Mode:
1523 Defines whether you want to support multicast TFTP as per
1524 rfc-2090; for example to work with atftp. Lets lots of targets
1525 tftp down the same boot image concurrently. Note: the Ethernet
1526 driver in use must provide a function: mcast() to join/leave a
1529 - BOOTP Recovery Mode:
1530 CONFIG_BOOTP_RANDOM_DELAY
1532 If you have many targets in a network that try to
1533 boot using BOOTP, you may want to avoid that all
1534 systems send out BOOTP requests at precisely the same
1535 moment (which would happen for instance at recovery
1536 from a power failure, when all systems will try to
1537 boot, thus flooding the BOOTP server. Defining
1538 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1539 inserted before sending out BOOTP requests. The
1540 following delays are inserted then:
1542 1st BOOTP request: delay 0 ... 1 sec
1543 2nd BOOTP request: delay 0 ... 2 sec
1544 3rd BOOTP request: delay 0 ... 4 sec
1546 BOOTP requests: delay 0 ... 8 sec
1548 - DHCP Advanced Options:
1549 You can fine tune the DHCP functionality by defining
1550 CONFIG_BOOTP_* symbols:
1552 CONFIG_BOOTP_SUBNETMASK
1553 CONFIG_BOOTP_GATEWAY
1554 CONFIG_BOOTP_HOSTNAME
1555 CONFIG_BOOTP_NISDOMAIN
1556 CONFIG_BOOTP_BOOTPATH
1557 CONFIG_BOOTP_BOOTFILESIZE
1560 CONFIG_BOOTP_SEND_HOSTNAME
1561 CONFIG_BOOTP_NTPSERVER
1562 CONFIG_BOOTP_TIMEOFFSET
1563 CONFIG_BOOTP_VENDOREX
1565 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1566 environment variable, not the BOOTP server.
1568 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1569 serverip from a DHCP server, it is possible that more
1570 than one DNS serverip is offered to the client.
1571 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1572 serverip will be stored in the additional environment
1573 variable "dnsip2". The first DNS serverip is always
1574 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1577 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1578 to do a dynamic update of a DNS server. To do this, they
1579 need the hostname of the DHCP requester.
1580 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1581 of the "hostname" environment variable is passed as
1582 option 12 to the DHCP server.
1584 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1586 A 32bit value in microseconds for a delay between
1587 receiving a "DHCP Offer" and sending the "DHCP Request".
1588 This fixes a problem with certain DHCP servers that don't
1589 respond 100% of the time to a "DHCP request". E.g. On an
1590 AT91RM9200 processor running at 180MHz, this delay needed
1591 to be *at least* 15,000 usec before a Windows Server 2003
1592 DHCP server would reply 100% of the time. I recommend at
1593 least 50,000 usec to be safe. The alternative is to hope
1594 that one of the retries will be successful but note that
1595 the DHCP timeout and retry process takes a longer than
1599 CONFIG_CDP_DEVICE_ID
1601 The device id used in CDP trigger frames.
1603 CONFIG_CDP_DEVICE_ID_PREFIX
1605 A two character string which is prefixed to the MAC address
1610 A printf format string which contains the ascii name of
1611 the port. Normally is set to "eth%d" which sets
1612 eth0 for the first Ethernet, eth1 for the second etc.
1614 CONFIG_CDP_CAPABILITIES
1616 A 32bit integer which indicates the device capabilities;
1617 0x00000010 for a normal host which does not forwards.
1621 An ascii string containing the version of the software.
1625 An ascii string containing the name of the platform.
1629 A 32bit integer sent on the trigger.
1631 CONFIG_CDP_POWER_CONSUMPTION
1633 A 16bit integer containing the power consumption of the
1634 device in .1 of milliwatts.
1636 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1638 A byte containing the id of the VLAN.
1640 - Status LED: CONFIG_STATUS_LED
1642 Several configurations allow to display the current
1643 status using a LED. For instance, the LED will blink
1644 fast while running U-Boot code, stop blinking as
1645 soon as a reply to a BOOTP request was received, and
1646 start blinking slow once the Linux kernel is running
1647 (supported by a status LED driver in the Linux
1648 kernel). Defining CONFIG_STATUS_LED enables this
1651 - CAN Support: CONFIG_CAN_DRIVER
1653 Defining CONFIG_CAN_DRIVER enables CAN driver support
1654 on those systems that support this (optional)
1655 feature, like the TQM8xxL modules.
1657 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1659 These enable I2C serial bus commands. Defining either of
1660 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1661 include the appropriate I2C driver for the selected CPU.
1663 This will allow you to use i2c commands at the u-boot
1664 command line (as long as you set CONFIG_CMD_I2C in
1665 CONFIG_COMMANDS) and communicate with i2c based realtime
1666 clock chips. See common/cmd_i2c.c for a description of the
1667 command line interface.
1669 CONFIG_HARD_I2C selects a hardware I2C controller.
1671 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1672 bit-banging) driver instead of CPM or similar hardware
1675 There are several other quantities that must also be
1676 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1678 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1679 to be the frequency (in Hz) at which you wish your i2c bus
1680 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1681 the CPU's i2c node address).
1683 Now, the u-boot i2c code for the mpc8xx
1684 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1685 and so its address should therefore be cleared to 0 (See,
1686 eg, MPC823e User's Manual p.16-473). So, set
1687 CONFIG_SYS_I2C_SLAVE to 0.
1689 CONFIG_SYS_I2C_INIT_MPC5XXX
1691 When a board is reset during an i2c bus transfer
1692 chips might think that the current transfer is still
1693 in progress. Reset the slave devices by sending start
1694 commands until the slave device responds.
1696 That's all that's required for CONFIG_HARD_I2C.
1698 If you use the software i2c interface (CONFIG_SOFT_I2C)
1699 then the following macros need to be defined (examples are
1700 from include/configs/lwmon.h):
1704 (Optional). Any commands necessary to enable the I2C
1705 controller or configure ports.
1707 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1711 (Only for MPC8260 CPU). The I/O port to use (the code
1712 assumes both bits are on the same port). Valid values
1713 are 0..3 for ports A..D.
1717 The code necessary to make the I2C data line active
1718 (driven). If the data line is open collector, this
1721 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1725 The code necessary to make the I2C data line tri-stated
1726 (inactive). If the data line is open collector, this
1729 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1733 Code that returns TRUE if the I2C data line is high,
1736 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1740 If <bit> is TRUE, sets the I2C data line high. If it
1741 is FALSE, it clears it (low).
1743 eg: #define I2C_SDA(bit) \
1744 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1745 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1749 If <bit> is TRUE, sets the I2C clock line high. If it
1750 is FALSE, it clears it (low).
1752 eg: #define I2C_SCL(bit) \
1753 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1754 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1758 This delay is invoked four times per clock cycle so this
1759 controls the rate of data transfer. The data rate thus
1760 is 1 / (I2C_DELAY * 4). Often defined to be something
1763 #define I2C_DELAY udelay(2)
1765 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1767 If your arch supports the generic GPIO framework (asm/gpio.h),
1768 then you may alternatively define the two GPIOs that are to be
1769 used as SCL / SDA. Any of the previous I2C_xxx macros will
1770 have GPIO-based defaults assigned to them as appropriate.
1772 You should define these to the GPIO value as given directly to
1773 the generic GPIO functions.
1775 CONFIG_SYS_I2C_INIT_BOARD
1777 When a board is reset during an i2c bus transfer
1778 chips might think that the current transfer is still
1779 in progress. On some boards it is possible to access
1780 the i2c SCLK line directly, either by using the
1781 processor pin as a GPIO or by having a second pin
1782 connected to the bus. If this option is defined a
1783 custom i2c_init_board() routine in boards/xxx/board.c
1784 is run early in the boot sequence.
1786 CONFIG_SYS_I2C_BOARD_LATE_INIT
1788 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1789 defined a custom i2c_board_late_init() routine in
1790 boards/xxx/board.c is run AFTER the operations in i2c_init()
1791 is completed. This callpoint can be used to unreset i2c bus
1792 using CPU i2c controller register accesses for CPUs whose i2c
1793 controller provide such a method. It is called at the end of
1794 i2c_init() to allow i2c_init operations to setup the i2c bus
1795 controller on the CPU (e.g. setting bus speed & slave address).
1797 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1799 This option enables configuration of bi_iic_fast[] flags
1800 in u-boot bd_info structure based on u-boot environment
1801 variable "i2cfast". (see also i2cfast)
1803 CONFIG_I2C_MULTI_BUS
1805 This option allows the use of multiple I2C buses, each of which
1806 must have a controller. At any point in time, only one bus is
1807 active. To switch to a different bus, use the 'i2c dev' command.
1808 Note that bus numbering is zero-based.
1810 CONFIG_SYS_I2C_NOPROBES
1812 This option specifies a list of I2C devices that will be skipped
1813 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1814 is set, specify a list of bus-device pairs. Otherwise, specify
1815 a 1D array of device addresses
1818 #undef CONFIG_I2C_MULTI_BUS
1819 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1821 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1823 #define CONFIG_I2C_MULTI_BUS
1824 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1826 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1828 CONFIG_SYS_SPD_BUS_NUM
1830 If defined, then this indicates the I2C bus number for DDR SPD.
1831 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1833 CONFIG_SYS_RTC_BUS_NUM
1835 If defined, then this indicates the I2C bus number for the RTC.
1836 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1838 CONFIG_SYS_DTT_BUS_NUM
1840 If defined, then this indicates the I2C bus number for the DTT.
1841 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1843 CONFIG_SYS_I2C_DTT_ADDR:
1845 If defined, specifies the I2C address of the DTT device.
1846 If not defined, then U-Boot uses predefined value for
1847 specified DTT device.
1851 Define this option if you want to use Freescale's I2C driver in
1852 drivers/i2c/fsl_i2c.c.
1856 Define this option if you have I2C devices reached over 1 .. n
1857 I2C Muxes like the pca9544a. This option addes a new I2C
1858 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1859 new I2C Bus to the existing I2C Busses. If you select the
1860 new Bus with "i2c dev", u-bbot sends first the commandos for
1861 the muxes to activate this new "bus".
1863 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1867 Adding a new I2C Bus reached over 2 pca9544a muxes
1868 The First mux with address 70 and channel 6
1869 The Second mux with address 71 and channel 4
1871 => i2c bus pca9544a:70:6:pca9544a:71:4
1873 Use the "i2c bus" command without parameter, to get a list
1874 of I2C Busses with muxes:
1877 Busses reached over muxes:
1879 reached over Mux(es):
1882 reached over Mux(es):
1887 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1888 u-boot first sends the command to the mux@70 to enable
1889 channel 6, and then the command to the mux@71 to enable
1892 After that, you can use the "normal" i2c commands as
1893 usual to communicate with your I2C devices behind
1896 This option is actually implemented for the bitbanging
1897 algorithm in common/soft_i2c.c and for the Hardware I2C
1898 Bus on the MPC8260. But it should be not so difficult
1899 to add this option to other architectures.
1901 CONFIG_SOFT_I2C_READ_REPEATED_START
1903 defining this will force the i2c_read() function in
1904 the soft_i2c driver to perform an I2C repeated start
1905 between writing the address pointer and reading the
1906 data. If this define is omitted the default behaviour
1907 of doing a stop-start sequence will be used. Most I2C
1908 devices can use either method, but some require one or
1911 - SPI Support: CONFIG_SPI
1913 Enables SPI driver (so far only tested with
1914 SPI EEPROM, also an instance works with Crystal A/D and
1915 D/As on the SACSng board)
1919 Enables the driver for SPI controller on SuperH. Currently
1920 only SH7757 is supported.
1924 Enables extended (16-bit) SPI EEPROM addressing.
1925 (symmetrical to CONFIG_I2C_X)
1929 Enables a software (bit-bang) SPI driver rather than
1930 using hardware support. This is a general purpose
1931 driver that only requires three general I/O port pins
1932 (two outputs, one input) to function. If this is
1933 defined, the board configuration must define several
1934 SPI configuration items (port pins to use, etc). For
1935 an example, see include/configs/sacsng.h.
1939 Enables a hardware SPI driver for general-purpose reads
1940 and writes. As with CONFIG_SOFT_SPI, the board configuration
1941 must define a list of chip-select function pointers.
1942 Currently supported on some MPC8xxx processors. For an
1943 example, see include/configs/mpc8349emds.h.
1947 Enables the driver for the SPI controllers on i.MX and MXC
1948 SoCs. Currently i.MX31/35/51 are supported.
1950 - FPGA Support: CONFIG_FPGA
1952 Enables FPGA subsystem.
1954 CONFIG_FPGA_<vendor>
1956 Enables support for specific chip vendors.
1959 CONFIG_FPGA_<family>
1961 Enables support for FPGA family.
1962 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1966 Specify the number of FPGA devices to support.
1968 CONFIG_SYS_FPGA_PROG_FEEDBACK
1970 Enable printing of hash marks during FPGA configuration.
1972 CONFIG_SYS_FPGA_CHECK_BUSY
1974 Enable checks on FPGA configuration interface busy
1975 status by the configuration function. This option
1976 will require a board or device specific function to
1981 If defined, a function that provides delays in the FPGA
1982 configuration driver.
1984 CONFIG_SYS_FPGA_CHECK_CTRLC
1985 Allow Control-C to interrupt FPGA configuration
1987 CONFIG_SYS_FPGA_CHECK_ERROR
1989 Check for configuration errors during FPGA bitfile
1990 loading. For example, abort during Virtex II
1991 configuration if the INIT_B line goes low (which
1992 indicated a CRC error).
1994 CONFIG_SYS_FPGA_WAIT_INIT
1996 Maximum time to wait for the INIT_B line to deassert
1997 after PROB_B has been deasserted during a Virtex II
1998 FPGA configuration sequence. The default time is 500
2001 CONFIG_SYS_FPGA_WAIT_BUSY
2003 Maximum time to wait for BUSY to deassert during
2004 Virtex II FPGA configuration. The default is 5 ms.
2006 CONFIG_SYS_FPGA_WAIT_CONFIG
2008 Time to wait after FPGA configuration. The default is
2011 - Configuration Management:
2014 If defined, this string will be added to the U-Boot
2015 version information (U_BOOT_VERSION)
2017 - Vendor Parameter Protection:
2019 U-Boot considers the values of the environment
2020 variables "serial#" (Board Serial Number) and
2021 "ethaddr" (Ethernet Address) to be parameters that
2022 are set once by the board vendor / manufacturer, and
2023 protects these variables from casual modification by
2024 the user. Once set, these variables are read-only,
2025 and write or delete attempts are rejected. You can
2026 change this behaviour:
2028 If CONFIG_ENV_OVERWRITE is #defined in your config
2029 file, the write protection for vendor parameters is
2030 completely disabled. Anybody can change or delete
2033 Alternatively, if you #define _both_ CONFIG_ETHADDR
2034 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2035 Ethernet address is installed in the environment,
2036 which can be changed exactly ONCE by the user. [The
2037 serial# is unaffected by this, i. e. it remains
2043 Define this variable to enable the reservation of
2044 "protected RAM", i. e. RAM which is not overwritten
2045 by U-Boot. Define CONFIG_PRAM to hold the number of
2046 kB you want to reserve for pRAM. You can overwrite
2047 this default value by defining an environment
2048 variable "pram" to the number of kB you want to
2049 reserve. Note that the board info structure will
2050 still show the full amount of RAM. If pRAM is
2051 reserved, a new environment variable "mem" will
2052 automatically be defined to hold the amount of
2053 remaining RAM in a form that can be passed as boot
2054 argument to Linux, for instance like that:
2056 setenv bootargs ... mem=\${mem}
2059 This way you can tell Linux not to use this memory,
2060 either, which results in a memory region that will
2061 not be affected by reboots.
2063 *WARNING* If your board configuration uses automatic
2064 detection of the RAM size, you must make sure that
2065 this memory test is non-destructive. So far, the
2066 following board configurations are known to be
2069 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2070 HERMES, IP860, RPXlite, LWMON, LANTEC,
2076 Define this variable to stop the system in case of a
2077 fatal error, so that you have to reset it manually.
2078 This is probably NOT a good idea for an embedded
2079 system where you want the system to reboot
2080 automatically as fast as possible, but it may be
2081 useful during development since you can try to debug
2082 the conditions that lead to the situation.
2084 CONFIG_NET_RETRY_COUNT
2086 This variable defines the number of retries for
2087 network operations like ARP, RARP, TFTP, or BOOTP
2088 before giving up the operation. If not defined, a
2089 default value of 5 is used.
2093 Timeout waiting for an ARP reply in milliseconds.
2095 - Command Interpreter:
2096 CONFIG_AUTO_COMPLETE
2098 Enable auto completion of commands using TAB.
2100 Note that this feature has NOT been implemented yet
2101 for the "hush" shell.
2104 CONFIG_SYS_HUSH_PARSER
2106 Define this variable to enable the "hush" shell (from
2107 Busybox) as command line interpreter, thus enabling
2108 powerful command line syntax like
2109 if...then...else...fi conditionals or `&&' and '||'
2110 constructs ("shell scripts").
2112 If undefined, you get the old, much simpler behaviour
2113 with a somewhat smaller memory footprint.
2116 CONFIG_SYS_PROMPT_HUSH_PS2
2118 This defines the secondary prompt string, which is
2119 printed when the command interpreter needs more input
2120 to complete a command. Usually "> ".
2124 In the current implementation, the local variables
2125 space and global environment variables space are
2126 separated. Local variables are those you define by
2127 simply typing `name=value'. To access a local
2128 variable later on, you have write `$name' or
2129 `${name}'; to execute the contents of a variable
2130 directly type `$name' at the command prompt.
2132 Global environment variables are those you use
2133 setenv/printenv to work with. To run a command stored
2134 in such a variable, you need to use the run command,
2135 and you must not use the '$' sign to access them.
2137 To store commands and special characters in a
2138 variable, please use double quotation marks
2139 surrounding the whole text of the variable, instead
2140 of the backslashes before semicolons and special
2143 - Commandline Editing and History:
2144 CONFIG_CMDLINE_EDITING
2146 Enable editing and History functions for interactive
2147 commandline input operations
2149 - Default Environment:
2150 CONFIG_EXTRA_ENV_SETTINGS
2152 Define this to contain any number of null terminated
2153 strings (variable = value pairs) that will be part of
2154 the default environment compiled into the boot image.
2156 For example, place something like this in your
2157 board's config file:
2159 #define CONFIG_EXTRA_ENV_SETTINGS \
2163 Warning: This method is based on knowledge about the
2164 internal format how the environment is stored by the
2165 U-Boot code. This is NOT an official, exported
2166 interface! Although it is unlikely that this format
2167 will change soon, there is no guarantee either.
2168 You better know what you are doing here.
2170 Note: overly (ab)use of the default environment is
2171 discouraged. Make sure to check other ways to preset
2172 the environment like the "source" command or the
2175 - DataFlash Support:
2176 CONFIG_HAS_DATAFLASH
2178 Defining this option enables DataFlash features and
2179 allows to read/write in Dataflash via the standard
2182 - SystemACE Support:
2185 Adding this option adds support for Xilinx SystemACE
2186 chips attached via some sort of local bus. The address
2187 of the chip must also be defined in the
2188 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2190 #define CONFIG_SYSTEMACE
2191 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2193 When SystemACE support is added, the "ace" device type
2194 becomes available to the fat commands, i.e. fatls.
2196 - TFTP Fixed UDP Port:
2199 If this is defined, the environment variable tftpsrcp
2200 is used to supply the TFTP UDP source port value.
2201 If tftpsrcp isn't defined, the normal pseudo-random port
2202 number generator is used.
2204 Also, the environment variable tftpdstp is used to supply
2205 the TFTP UDP destination port value. If tftpdstp isn't
2206 defined, the normal port 69 is used.
2208 The purpose for tftpsrcp is to allow a TFTP server to
2209 blindly start the TFTP transfer using the pre-configured
2210 target IP address and UDP port. This has the effect of
2211 "punching through" the (Windows XP) firewall, allowing
2212 the remainder of the TFTP transfer to proceed normally.
2213 A better solution is to properly configure the firewall,
2214 but sometimes that is not allowed.
2216 - Show boot progress:
2217 CONFIG_SHOW_BOOT_PROGRESS
2219 Defining this option allows to add some board-
2220 specific code (calling a user-provided function
2221 "show_boot_progress(int)") that enables you to show
2222 the system's boot progress on some display (for
2223 example, some LED's) on your board. At the moment,
2224 the following checkpoints are implemented:
2226 Legacy uImage format:
2229 1 common/cmd_bootm.c before attempting to boot an image
2230 -1 common/cmd_bootm.c Image header has bad magic number
2231 2 common/cmd_bootm.c Image header has correct magic number
2232 -2 common/cmd_bootm.c Image header has bad checksum
2233 3 common/cmd_bootm.c Image header has correct checksum
2234 -3 common/cmd_bootm.c Image data has bad checksum
2235 4 common/cmd_bootm.c Image data has correct checksum
2236 -4 common/cmd_bootm.c Image is for unsupported architecture
2237 5 common/cmd_bootm.c Architecture check OK
2238 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2239 6 common/cmd_bootm.c Image Type check OK
2240 -6 common/cmd_bootm.c gunzip uncompression error
2241 -7 common/cmd_bootm.c Unimplemented compression type
2242 7 common/cmd_bootm.c Uncompression OK
2243 8 common/cmd_bootm.c No uncompress/copy overwrite error
2244 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2246 9 common/image.c Start initial ramdisk verification
2247 -10 common/image.c Ramdisk header has bad magic number
2248 -11 common/image.c Ramdisk header has bad checksum
2249 10 common/image.c Ramdisk header is OK
2250 -12 common/image.c Ramdisk data has bad checksum
2251 11 common/image.c Ramdisk data has correct checksum
2252 12 common/image.c Ramdisk verification complete, start loading
2253 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2254 13 common/image.c Start multifile image verification
2255 14 common/image.c No initial ramdisk, no multifile, continue.
2257 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2259 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2260 -31 post/post.c POST test failed, detected by post_output_backlog()
2261 -32 post/post.c POST test failed, detected by post_run_single()
2263 34 common/cmd_doc.c before loading a Image from a DOC device
2264 -35 common/cmd_doc.c Bad usage of "doc" command
2265 35 common/cmd_doc.c correct usage of "doc" command
2266 -36 common/cmd_doc.c No boot device
2267 36 common/cmd_doc.c correct boot device
2268 -37 common/cmd_doc.c Unknown Chip ID on boot device
2269 37 common/cmd_doc.c correct chip ID found, device available
2270 -38 common/cmd_doc.c Read Error on boot device
2271 38 common/cmd_doc.c reading Image header from DOC device OK
2272 -39 common/cmd_doc.c Image header has bad magic number
2273 39 common/cmd_doc.c Image header has correct magic number
2274 -40 common/cmd_doc.c Error reading Image from DOC device
2275 40 common/cmd_doc.c Image header has correct magic number
2276 41 common/cmd_ide.c before loading a Image from a IDE device
2277 -42 common/cmd_ide.c Bad usage of "ide" command
2278 42 common/cmd_ide.c correct usage of "ide" command
2279 -43 common/cmd_ide.c No boot device
2280 43 common/cmd_ide.c boot device found
2281 -44 common/cmd_ide.c Device not available
2282 44 common/cmd_ide.c Device available
2283 -45 common/cmd_ide.c wrong partition selected
2284 45 common/cmd_ide.c partition selected
2285 -46 common/cmd_ide.c Unknown partition table
2286 46 common/cmd_ide.c valid partition table found
2287 -47 common/cmd_ide.c Invalid partition type
2288 47 common/cmd_ide.c correct partition type
2289 -48 common/cmd_ide.c Error reading Image Header on boot device
2290 48 common/cmd_ide.c reading Image Header from IDE device OK
2291 -49 common/cmd_ide.c Image header has bad magic number
2292 49 common/cmd_ide.c Image header has correct magic number
2293 -50 common/cmd_ide.c Image header has bad checksum
2294 50 common/cmd_ide.c Image header has correct checksum
2295 -51 common/cmd_ide.c Error reading Image from IDE device
2296 51 common/cmd_ide.c reading Image from IDE device OK
2297 52 common/cmd_nand.c before loading a Image from a NAND device
2298 -53 common/cmd_nand.c Bad usage of "nand" command
2299 53 common/cmd_nand.c correct usage of "nand" command
2300 -54 common/cmd_nand.c No boot device
2301 54 common/cmd_nand.c boot device found
2302 -55 common/cmd_nand.c Unknown Chip ID on boot device
2303 55 common/cmd_nand.c correct chip ID found, device available
2304 -56 common/cmd_nand.c Error reading Image Header on boot device
2305 56 common/cmd_nand.c reading Image Header from NAND device OK
2306 -57 common/cmd_nand.c Image header has bad magic number
2307 57 common/cmd_nand.c Image header has correct magic number
2308 -58 common/cmd_nand.c Error reading Image from NAND device
2309 58 common/cmd_nand.c reading Image from NAND device OK
2311 -60 common/env_common.c Environment has a bad CRC, using default
2313 64 net/eth.c starting with Ethernet configuration.
2314 -64 net/eth.c no Ethernet found.
2315 65 net/eth.c Ethernet found.
2317 -80 common/cmd_net.c usage wrong
2318 80 common/cmd_net.c before calling NetLoop()
2319 -81 common/cmd_net.c some error in NetLoop() occurred
2320 81 common/cmd_net.c NetLoop() back without error
2321 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2322 82 common/cmd_net.c trying automatic boot
2323 83 common/cmd_net.c running "source" command
2324 -83 common/cmd_net.c some error in automatic boot or "source" command
2325 84 common/cmd_net.c end without errors
2330 100 common/cmd_bootm.c Kernel FIT Image has correct format
2331 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2332 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2333 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2334 102 common/cmd_bootm.c Kernel unit name specified
2335 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2336 103 common/cmd_bootm.c Found configuration node
2337 104 common/cmd_bootm.c Got kernel subimage node offset
2338 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2339 105 common/cmd_bootm.c Kernel subimage hash verification OK
2340 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2341 106 common/cmd_bootm.c Architecture check OK
2342 -106 common/cmd_bootm.c Kernel subimage has wrong type
2343 107 common/cmd_bootm.c Kernel subimage type OK
2344 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2345 108 common/cmd_bootm.c Got kernel subimage data/size
2346 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2347 -109 common/cmd_bootm.c Can't get kernel subimage type
2348 -110 common/cmd_bootm.c Can't get kernel subimage comp
2349 -111 common/cmd_bootm.c Can't get kernel subimage os
2350 -112 common/cmd_bootm.c Can't get kernel subimage load address
2351 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2353 120 common/image.c Start initial ramdisk verification
2354 -120 common/image.c Ramdisk FIT image has incorrect format
2355 121 common/image.c Ramdisk FIT image has correct format
2356 122 common/image.c No ramdisk subimage unit name, using configuration
2357 -122 common/image.c Can't get configuration for ramdisk subimage
2358 123 common/image.c Ramdisk unit name specified
2359 -124 common/image.c Can't get ramdisk subimage node offset
2360 125 common/image.c Got ramdisk subimage node offset
2361 -125 common/image.c Ramdisk subimage hash verification failed
2362 126 common/image.c Ramdisk subimage hash verification OK
2363 -126 common/image.c Ramdisk subimage for unsupported architecture
2364 127 common/image.c Architecture check OK
2365 -127 common/image.c Can't get ramdisk subimage data/size
2366 128 common/image.c Got ramdisk subimage data/size
2367 129 common/image.c Can't get ramdisk load address
2368 -129 common/image.c Got ramdisk load address
2370 -130 common/cmd_doc.c Incorrect FIT image format
2371 131 common/cmd_doc.c FIT image format OK
2373 -140 common/cmd_ide.c Incorrect FIT image format
2374 141 common/cmd_ide.c FIT image format OK
2376 -150 common/cmd_nand.c Incorrect FIT image format
2377 151 common/cmd_nand.c FIT image format OK
2379 - Standalone program support:
2380 CONFIG_STANDALONE_LOAD_ADDR
2382 This option defines a board specific value for the
2383 address where standalone program gets loaded, thus
2384 overwriting the architecture dependent default
2387 - Frame Buffer Address:
2390 Define CONFIG_FB_ADDR if you want to use specific
2391 address for frame buffer.
2392 Then system will reserve the frame buffer address to
2393 defined address instead of lcd_setmem (this function
2394 grabs the memory for frame buffer by panel's size).
2396 Please see board_init_f function.
2398 - Automatic software updates via TFTP server
2400 CONFIG_UPDATE_TFTP_CNT_MAX
2401 CONFIG_UPDATE_TFTP_MSEC_MAX
2403 These options enable and control the auto-update feature;
2404 for a more detailed description refer to doc/README.update.
2406 - MTD Support (mtdparts command, UBI support)
2409 Adds the MTD device infrastructure from the Linux kernel.
2410 Needed for mtdparts command support.
2412 CONFIG_MTD_PARTITIONS
2414 Adds the MTD partitioning infrastructure from the Linux
2415 kernel. Needed for UBI support.
2419 Enable building of SPL globally.
2421 CONFIG_SPL_TEXT_BASE
2422 TEXT_BASE for linking the SPL binary.
2425 LDSCRIPT for linking the SPL binary.
2427 CONFIG_SPL_LIBCOMMON_SUPPORT
2428 Support for common/libcommon.o in SPL binary
2430 CONFIG_SPL_LIBDISK_SUPPORT
2431 Support for disk/libdisk.o in SPL binary
2433 CONFIG_SPL_I2C_SUPPORT
2434 Support for drivers/i2c/libi2c.o in SPL binary
2436 CONFIG_SPL_GPIO_SUPPORT
2437 Support for drivers/gpio/libgpio.o in SPL binary
2439 CONFIG_SPL_MMC_SUPPORT
2440 Support for drivers/mmc/libmmc.o in SPL binary
2442 CONFIG_SPL_SERIAL_SUPPORT
2443 Support for drivers/serial/libserial.o in SPL binary
2445 CONFIG_SPL_SPI_FLASH_SUPPORT
2446 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2448 CONFIG_SPL_SPI_SUPPORT
2449 Support for drivers/spi/libspi.o in SPL binary
2451 CONFIG_SPL_FAT_SUPPORT
2452 Support for fs/fat/libfat.o in SPL binary
2454 CONFIG_SPL_LIBGENERIC_SUPPORT
2455 Support for lib/libgeneric.o in SPL binary
2460 [so far only for SMDK2400 boards]
2462 - Modem support enable:
2463 CONFIG_MODEM_SUPPORT
2465 - RTS/CTS Flow control enable:
2468 - Modem debug support:
2469 CONFIG_MODEM_SUPPORT_DEBUG
2471 Enables debugging stuff (char screen[1024], dbg())
2472 for modem support. Useful only with BDI2000.
2474 - Interrupt support (PPC):
2476 There are common interrupt_init() and timer_interrupt()
2477 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2478 for CPU specific initialization. interrupt_init_cpu()
2479 should set decrementer_count to appropriate value. If
2480 CPU resets decrementer automatically after interrupt
2481 (ppc4xx) it should set decrementer_count to zero.
2482 timer_interrupt() calls timer_interrupt_cpu() for CPU
2483 specific handling. If board has watchdog / status_led
2484 / other_activity_monitor it works automatically from
2485 general timer_interrupt().
2489 In the target system modem support is enabled when a
2490 specific key (key combination) is pressed during
2491 power-on. Otherwise U-Boot will boot normally
2492 (autoboot). The key_pressed() function is called from
2493 board_init(). Currently key_pressed() is a dummy
2494 function, returning 1 and thus enabling modem
2497 If there are no modem init strings in the
2498 environment, U-Boot proceed to autoboot; the
2499 previous output (banner, info printfs) will be
2502 See also: doc/README.Modem
2504 Board initialization settings:
2505 ------------------------------
2507 During Initialization u-boot calls a number of board specific functions
2508 to allow the preparation of board specific prerequisites, e.g. pin setup
2509 before drivers are initialized. To enable these callbacks the
2510 following configuration macros have to be defined. Currently this is
2511 architecture specific, so please check arch/your_architecture/lib/board.c
2512 typically in board_init_f() and board_init_r().
2514 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2515 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2516 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2517 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2519 Configuration Settings:
2520 -----------------------
2522 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2523 undefine this when you're short of memory.
2525 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2526 width of the commands listed in the 'help' command output.
2528 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2529 prompt for user input.
2531 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2533 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2535 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2537 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2538 the application (usually a Linux kernel) when it is
2541 - CONFIG_SYS_BAUDRATE_TABLE:
2542 List of legal baudrate settings for this board.
2544 - CONFIG_SYS_CONSOLE_INFO_QUIET
2545 Suppress display of console information at boot.
2547 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2548 If the board specific function
2549 extern int overwrite_console (void);
2550 returns 1, the stdin, stderr and stdout are switched to the
2551 serial port, else the settings in the environment are used.
2553 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2554 Enable the call to overwrite_console().
2556 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2557 Enable overwrite of previous console environment settings.
2559 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2560 Begin and End addresses of the area used by the
2563 - CONFIG_SYS_ALT_MEMTEST:
2564 Enable an alternate, more extensive memory test.
2566 - CONFIG_SYS_MEMTEST_SCRATCH:
2567 Scratch address used by the alternate memory test
2568 You only need to set this if address zero isn't writeable
2570 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2571 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2572 this specified memory area will get subtracted from the top
2573 (end) of RAM and won't get "touched" at all by U-Boot. By
2574 fixing up gd->ram_size the Linux kernel should gets passed
2575 the now "corrected" memory size and won't touch it either.
2576 This should work for arch/ppc and arch/powerpc. Only Linux
2577 board ports in arch/powerpc with bootwrapper support that
2578 recalculate the memory size from the SDRAM controller setup
2579 will have to get fixed in Linux additionally.
2581 This option can be used as a workaround for the 440EPx/GRx
2582 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2585 WARNING: Please make sure that this value is a multiple of
2586 the Linux page size (normally 4k). If this is not the case,
2587 then the end address of the Linux memory will be located at a
2588 non page size aligned address and this could cause major
2591 - CONFIG_SYS_TFTP_LOADADDR:
2592 Default load address for network file downloads
2594 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2595 Enable temporary baudrate change while serial download
2597 - CONFIG_SYS_SDRAM_BASE:
2598 Physical start address of SDRAM. _Must_ be 0 here.
2600 - CONFIG_SYS_MBIO_BASE:
2601 Physical start address of Motherboard I/O (if using a
2604 - CONFIG_SYS_FLASH_BASE:
2605 Physical start address of Flash memory.
2607 - CONFIG_SYS_MONITOR_BASE:
2608 Physical start address of boot monitor code (set by
2609 make config files to be same as the text base address
2610 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2611 CONFIG_SYS_FLASH_BASE when booting from flash.
2613 - CONFIG_SYS_MONITOR_LEN:
2614 Size of memory reserved for monitor code, used to
2615 determine _at_compile_time_ (!) if the environment is
2616 embedded within the U-Boot image, or in a separate
2619 - CONFIG_SYS_MALLOC_LEN:
2620 Size of DRAM reserved for malloc() use.
2622 - CONFIG_SYS_BOOTM_LEN:
2623 Normally compressed uImages are limited to an
2624 uncompressed size of 8 MBytes. If this is not enough,
2625 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2626 to adjust this setting to your needs.
2628 - CONFIG_SYS_BOOTMAPSZ:
2629 Maximum size of memory mapped by the startup code of
2630 the Linux kernel; all data that must be processed by
2631 the Linux kernel (bd_info, boot arguments, FDT blob if
2632 used) must be put below this limit, unless "bootm_low"
2633 enviroment variable is defined and non-zero. In such case
2634 all data for the Linux kernel must be between "bootm_low"
2635 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2636 variable "bootm_mapsize" will override the value of
2637 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2638 then the value in "bootm_size" will be used instead.
2640 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2641 Enable initrd_high functionality. If defined then the
2642 initrd_high feature is enabled and the bootm ramdisk subcommand
2645 - CONFIG_SYS_BOOT_GET_CMDLINE:
2646 Enables allocating and saving kernel cmdline in space between
2647 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2649 - CONFIG_SYS_BOOT_GET_KBD:
2650 Enables allocating and saving a kernel copy of the bd_info in
2651 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2653 - CONFIG_SYS_MAX_FLASH_BANKS:
2654 Max number of Flash memory banks
2656 - CONFIG_SYS_MAX_FLASH_SECT:
2657 Max number of sectors on a Flash chip
2659 - CONFIG_SYS_FLASH_ERASE_TOUT:
2660 Timeout for Flash erase operations (in ms)
2662 - CONFIG_SYS_FLASH_WRITE_TOUT:
2663 Timeout for Flash write operations (in ms)
2665 - CONFIG_SYS_FLASH_LOCK_TOUT
2666 Timeout for Flash set sector lock bit operation (in ms)
2668 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2669 Timeout for Flash clear lock bits operation (in ms)
2671 - CONFIG_SYS_FLASH_PROTECTION
2672 If defined, hardware flash sectors protection is used
2673 instead of U-Boot software protection.
2675 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2677 Enable TFTP transfers directly to flash memory;
2678 without this option such a download has to be
2679 performed in two steps: (1) download to RAM, and (2)
2680 copy from RAM to flash.
2682 The two-step approach is usually more reliable, since
2683 you can check if the download worked before you erase
2684 the flash, but in some situations (when system RAM is
2685 too limited to allow for a temporary copy of the
2686 downloaded image) this option may be very useful.
2688 - CONFIG_SYS_FLASH_CFI:
2689 Define if the flash driver uses extra elements in the
2690 common flash structure for storing flash geometry.
2692 - CONFIG_FLASH_CFI_DRIVER
2693 This option also enables the building of the cfi_flash driver
2694 in the drivers directory
2696 - CONFIG_FLASH_CFI_MTD
2697 This option enables the building of the cfi_mtd driver
2698 in the drivers directory. The driver exports CFI flash
2701 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2702 Use buffered writes to flash.
2704 - CONFIG_FLASH_SPANSION_S29WS_N
2705 s29ws-n MirrorBit flash has non-standard addresses for buffered
2708 - CONFIG_SYS_FLASH_QUIET_TEST
2709 If this option is defined, the common CFI flash doesn't
2710 print it's warning upon not recognized FLASH banks. This
2711 is useful, if some of the configured banks are only
2712 optionally available.
2714 - CONFIG_FLASH_SHOW_PROGRESS
2715 If defined (must be an integer), print out countdown
2716 digits and dots. Recommended value: 45 (9..1) for 80
2717 column displays, 15 (3..1) for 40 column displays.
2719 - CONFIG_SYS_RX_ETH_BUFFER:
2720 Defines the number of Ethernet receive buffers. On some
2721 Ethernet controllers it is recommended to set this value
2722 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2723 buffers can be full shortly after enabling the interface
2724 on high Ethernet traffic.
2725 Defaults to 4 if not defined.
2727 - CONFIG_ENV_MAX_ENTRIES
2729 Maximum number of entries in the hash table that is used
2730 internally to store the environment settings. The default
2731 setting is supposed to be generous and should work in most
2732 cases. This setting can be used to tune behaviour; see
2733 lib/hashtable.c for details.
2735 The following definitions that deal with the placement and management
2736 of environment data (variable area); in general, we support the
2737 following configurations:
2739 - CONFIG_BUILD_ENVCRC:
2741 Builds up envcrc with the target environment so that external utils
2742 may easily extract it and embed it in final U-Boot images.
2744 - CONFIG_ENV_IS_IN_FLASH:
2746 Define this if the environment is in flash memory.
2748 a) The environment occupies one whole flash sector, which is
2749 "embedded" in the text segment with the U-Boot code. This
2750 happens usually with "bottom boot sector" or "top boot
2751 sector" type flash chips, which have several smaller
2752 sectors at the start or the end. For instance, such a
2753 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2754 such a case you would place the environment in one of the
2755 4 kB sectors - with U-Boot code before and after it. With
2756 "top boot sector" type flash chips, you would put the
2757 environment in one of the last sectors, leaving a gap
2758 between U-Boot and the environment.
2760 - CONFIG_ENV_OFFSET:
2762 Offset of environment data (variable area) to the
2763 beginning of flash memory; for instance, with bottom boot
2764 type flash chips the second sector can be used: the offset
2765 for this sector is given here.
2767 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2771 This is just another way to specify the start address of
2772 the flash sector containing the environment (instead of
2775 - CONFIG_ENV_SECT_SIZE:
2777 Size of the sector containing the environment.
2780 b) Sometimes flash chips have few, equal sized, BIG sectors.
2781 In such a case you don't want to spend a whole sector for
2786 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2787 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2788 of this flash sector for the environment. This saves
2789 memory for the RAM copy of the environment.
2791 It may also save flash memory if you decide to use this
2792 when your environment is "embedded" within U-Boot code,
2793 since then the remainder of the flash sector could be used
2794 for U-Boot code. It should be pointed out that this is
2795 STRONGLY DISCOURAGED from a robustness point of view:
2796 updating the environment in flash makes it always
2797 necessary to erase the WHOLE sector. If something goes
2798 wrong before the contents has been restored from a copy in
2799 RAM, your target system will be dead.
2801 - CONFIG_ENV_ADDR_REDUND
2802 CONFIG_ENV_SIZE_REDUND
2804 These settings describe a second storage area used to hold
2805 a redundant copy of the environment data, so that there is
2806 a valid backup copy in case there is a power failure during
2807 a "saveenv" operation.
2809 BE CAREFUL! Any changes to the flash layout, and some changes to the
2810 source code will make it necessary to adapt <board>/u-boot.lds*
2814 - CONFIG_ENV_IS_IN_NVRAM:
2816 Define this if you have some non-volatile memory device
2817 (NVRAM, battery buffered SRAM) which you want to use for the
2823 These two #defines are used to determine the memory area you
2824 want to use for environment. It is assumed that this memory
2825 can just be read and written to, without any special
2828 BE CAREFUL! The first access to the environment happens quite early
2829 in U-Boot initalization (when we try to get the setting of for the
2830 console baudrate). You *MUST* have mapped your NVRAM area then, or
2833 Please note that even with NVRAM we still use a copy of the
2834 environment in RAM: we could work on NVRAM directly, but we want to
2835 keep settings there always unmodified except somebody uses "saveenv"
2836 to save the current settings.
2839 - CONFIG_ENV_IS_IN_EEPROM:
2841 Use this if you have an EEPROM or similar serial access
2842 device and a driver for it.
2844 - CONFIG_ENV_OFFSET:
2847 These two #defines specify the offset and size of the
2848 environment area within the total memory of your EEPROM.
2850 - CONFIG_SYS_I2C_EEPROM_ADDR:
2851 If defined, specified the chip address of the EEPROM device.
2852 The default address is zero.
2854 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2855 If defined, the number of bits used to address bytes in a
2856 single page in the EEPROM device. A 64 byte page, for example
2857 would require six bits.
2859 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2860 If defined, the number of milliseconds to delay between
2861 page writes. The default is zero milliseconds.
2863 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2864 The length in bytes of the EEPROM memory array address. Note
2865 that this is NOT the chip address length!
2867 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2868 EEPROM chips that implement "address overflow" are ones
2869 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2870 address and the extra bits end up in the "chip address" bit
2871 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2874 Note that we consider the length of the address field to
2875 still be one byte because the extra address bits are hidden
2876 in the chip address.
2878 - CONFIG_SYS_EEPROM_SIZE:
2879 The size in bytes of the EEPROM device.
2881 - CONFIG_ENV_EEPROM_IS_ON_I2C
2882 define this, if you have I2C and SPI activated, and your
2883 EEPROM, which holds the environment, is on the I2C bus.
2885 - CONFIG_I2C_ENV_EEPROM_BUS
2886 if you have an Environment on an EEPROM reached over
2887 I2C muxes, you can define here, how to reach this
2888 EEPROM. For example:
2890 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2892 EEPROM which holds the environment, is reached over
2893 a pca9547 i2c mux with address 0x70, channel 3.
2895 - CONFIG_ENV_IS_IN_DATAFLASH:
2897 Define this if you have a DataFlash memory device which you
2898 want to use for the environment.
2900 - CONFIG_ENV_OFFSET:
2904 These three #defines specify the offset and size of the
2905 environment area within the total memory of your DataFlash placed
2906 at the specified address.
2908 - CONFIG_ENV_IS_IN_NAND:
2910 Define this if you have a NAND device which you want to use
2911 for the environment.
2913 - CONFIG_ENV_OFFSET:
2916 These two #defines specify the offset and size of the environment
2917 area within the first NAND device. CONFIG_ENV_OFFSET must be
2918 aligned to an erase block boundary.
2920 - CONFIG_ENV_OFFSET_REDUND (optional):
2922 This setting describes a second storage area of CONFIG_ENV_SIZE
2923 size used to hold a redundant copy of the environment data, so
2924 that there is a valid backup copy in case there is a power failure
2925 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2926 aligned to an erase block boundary.
2928 - CONFIG_ENV_RANGE (optional):
2930 Specifies the length of the region in which the environment
2931 can be written. This should be a multiple of the NAND device's
2932 block size. Specifying a range with more erase blocks than
2933 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2934 the range to be avoided.
2936 - CONFIG_ENV_OFFSET_OOB (optional):
2938 Enables support for dynamically retrieving the offset of the
2939 environment from block zero's out-of-band data. The
2940 "nand env.oob" command can be used to record this offset.
2941 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2942 using CONFIG_ENV_OFFSET_OOB.
2944 - CONFIG_NAND_ENV_DST
2946 Defines address in RAM to which the nand_spl code should copy the
2947 environment. If redundant environment is used, it will be copied to
2948 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2950 - CONFIG_SYS_SPI_INIT_OFFSET
2952 Defines offset to the initial SPI buffer area in DPRAM. The
2953 area is used at an early stage (ROM part) if the environment
2954 is configured to reside in the SPI EEPROM: We need a 520 byte
2955 scratch DPRAM area. It is used between the two initialization
2956 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2957 to be a good choice since it makes it far enough from the
2958 start of the data area as well as from the stack pointer.
2960 Please note that the environment is read-only until the monitor
2961 has been relocated to RAM and a RAM copy of the environment has been
2962 created; also, when using EEPROM you will have to use getenv_f()
2963 until then to read environment variables.
2965 The environment is protected by a CRC32 checksum. Before the monitor
2966 is relocated into RAM, as a result of a bad CRC you will be working
2967 with the compiled-in default environment - *silently*!!! [This is
2968 necessary, because the first environment variable we need is the
2969 "baudrate" setting for the console - if we have a bad CRC, we don't
2970 have any device yet where we could complain.]
2972 Note: once the monitor has been relocated, then it will complain if
2973 the default environment is used; a new CRC is computed as soon as you
2974 use the "saveenv" command to store a valid environment.
2976 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2977 Echo the inverted Ethernet link state to the fault LED.
2979 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2980 also needs to be defined.
2982 - CONFIG_SYS_FAULT_MII_ADDR:
2983 MII address of the PHY to check for the Ethernet link state.
2985 - CONFIG_NS16550_MIN_FUNCTIONS:
2986 Define this if you desire to only have use of the NS16550_init
2987 and NS16550_putc functions for the serial driver located at
2988 drivers/serial/ns16550.c. This option is useful for saving
2989 space for already greatly restricted images, including but not
2990 limited to NAND_SPL configurations.
2992 Low Level (hardware related) configuration options:
2993 ---------------------------------------------------
2995 - CONFIG_SYS_CACHELINE_SIZE:
2996 Cache Line Size of the CPU.
2998 - CONFIG_SYS_DEFAULT_IMMR:
2999 Default address of the IMMR after system reset.
3001 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
3002 and RPXsuper) to be able to adjust the position of
3003 the IMMR register after a reset.
3005 - CONFIG_SYS_CCSRBAR_DEFAULT:
3006 Default (power-on reset) physical address of CCSR on Freescale
3009 - CONFIG_SYS_CCSRBAR:
3010 Virtual address of CCSR. On a 32-bit build, this is typically
3011 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3013 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
3014 for cross-platform code that uses that macro instead.
3016 - CONFIG_SYS_CCSRBAR_PHYS:
3017 Physical address of CCSR. CCSR can be relocated to a new
3018 physical address, if desired. In this case, this macro should
3019 be set to that address. Otherwise, it should be set to the
3020 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3021 is typically relocated on 36-bit builds. It is recommended
3022 that this macro be defined via the _HIGH and _LOW macros:
3024 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3025 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3027 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3028 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3029 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3030 used in assembly code, so it must not contain typecasts or
3031 integer size suffixes (e.g. "ULL").
3033 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3034 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3035 used in assembly code, so it must not contain typecasts or
3036 integer size suffixes (e.g. "ULL").
3038 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3039 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3040 forced to a value that ensures that CCSR is not relocated.
3042 - Floppy Disk Support:
3043 CONFIG_SYS_FDC_DRIVE_NUMBER
3045 the default drive number (default value 0)
3047 CONFIG_SYS_ISA_IO_STRIDE
3049 defines the spacing between FDC chipset registers
3052 CONFIG_SYS_ISA_IO_OFFSET
3054 defines the offset of register from address. It
3055 depends on which part of the data bus is connected to
3056 the FDC chipset. (default value 0)
3058 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3059 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3062 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3063 fdc_hw_init() is called at the beginning of the FDC
3064 setup. fdc_hw_init() must be provided by the board
3065 source code. It is used to make hardware dependant
3069 Most IDE controllers were designed to be connected with PCI
3070 interface. Only few of them were designed for AHB interface.
3071 When software is doing ATA command and data transfer to
3072 IDE devices through IDE-AHB controller, some additional
3073 registers accessing to these kind of IDE-AHB controller
3076 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3077 DO NOT CHANGE unless you know exactly what you're
3078 doing! (11-4) [MPC8xx/82xx systems only]
3080 - CONFIG_SYS_INIT_RAM_ADDR:
3082 Start address of memory area that can be used for
3083 initial data and stack; please note that this must be
3084 writable memory that is working WITHOUT special
3085 initialization, i. e. you CANNOT use normal RAM which
3086 will become available only after programming the
3087 memory controller and running certain initialization
3090 U-Boot uses the following memory types:
3091 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3092 - MPC824X: data cache
3093 - PPC4xx: data cache
3095 - CONFIG_SYS_GBL_DATA_OFFSET:
3097 Offset of the initial data structure in the memory
3098 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3099 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3100 data is located at the end of the available space
3101 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3102 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3103 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3104 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3107 On the MPC824X (or other systems that use the data
3108 cache for initial memory) the address chosen for
3109 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3110 point to an otherwise UNUSED address space between
3111 the top of RAM and the start of the PCI space.
3113 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3115 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3117 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3119 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3121 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3123 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3125 - CONFIG_SYS_OR_TIMING_SDRAM:
3128 - CONFIG_SYS_MAMR_PTA:
3129 periodic timer for refresh
3131 - CONFIG_SYS_DER: Debug Event Register (37-47)
3133 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3134 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3135 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3136 CONFIG_SYS_BR1_PRELIM:
3137 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3139 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3140 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3141 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3142 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3144 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3145 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3146 Machine Mode Register and Memory Periodic Timer
3147 Prescaler definitions (SDRAM timing)
3149 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3150 enable I2C microcode relocation patch (MPC8xx);
3151 define relocation offset in DPRAM [DSP2]
3153 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3154 enable SMC microcode relocation patch (MPC8xx);
3155 define relocation offset in DPRAM [SMC1]
3157 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3158 enable SPI microcode relocation patch (MPC8xx);
3159 define relocation offset in DPRAM [SCC4]
3161 - CONFIG_SYS_USE_OSCCLK:
3162 Use OSCM clock mode on MBX8xx board. Be careful,
3163 wrong setting might damage your board. Read
3164 doc/README.MBX before setting this variable!
3166 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3167 Offset of the bootmode word in DPRAM used by post
3168 (Power On Self Tests). This definition overrides
3169 #define'd default value in commproc.h resp.
3172 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3173 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3174 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3175 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3176 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3177 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3178 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3179 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3180 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3182 - CONFIG_PCI_DISABLE_PCIE:
3183 Disable PCI-Express on systems where it is supported but not
3187 Chip has SRIO or not
3190 Board has SRIO 1 port available
3193 Board has SRIO 2 port available
3195 - CONFIG_SYS_SRIOn_MEM_VIRT:
3196 Virtual Address of SRIO port 'n' memory region
3198 - CONFIG_SYS_SRIOn_MEM_PHYS:
3199 Physical Address of SRIO port 'n' memory region
3201 - CONFIG_SYS_SRIOn_MEM_SIZE:
3202 Size of SRIO port 'n' memory region
3204 - CONFIG_SYS_NDFC_16
3205 Defined to tell the NDFC that the NAND chip is using a
3208 - CONFIG_SYS_NDFC_EBC0_CFG
3209 Sets the EBC0_CFG register for the NDFC. If not defined
3210 a default value will be used.
3213 Get DDR timing information from an I2C EEPROM. Common
3214 with pluggable memory modules such as SODIMMs
3217 I2C address of the SPD EEPROM
3219 - CONFIG_SYS_SPD_BUS_NUM
3220 If SPD EEPROM is on an I2C bus other than the first
3221 one, specify here. Note that the value must resolve
3222 to something your driver can deal with.
3224 - CONFIG_SYS_DDR_RAW_TIMING
3225 Get DDR timing information from other than SPD. Common with
3226 soldered DDR chips onboard without SPD. DDR raw timing
3227 parameters are extracted from datasheet and hard-coded into
3228 header files or board specific files.
3230 - CONFIG_FSL_DDR_INTERACTIVE
3231 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3233 - CONFIG_SYS_83XX_DDR_USES_CS0
3234 Only for 83xx systems. If specified, then DDR should
3235 be configured using CS0 and CS1 instead of CS2 and CS3.
3237 - CONFIG_ETHER_ON_FEC[12]
3238 Define to enable FEC[12] on a 8xx series processor.
3240 - CONFIG_FEC[12]_PHY
3241 Define to the hardcoded PHY address which corresponds
3242 to the given FEC; i. e.
3243 #define CONFIG_FEC1_PHY 4
3244 means that the PHY with address 4 is connected to FEC1
3246 When set to -1, means to probe for first available.
3248 - CONFIG_FEC[12]_PHY_NORXERR
3249 The PHY does not have a RXERR line (RMII only).
3250 (so program the FEC to ignore it).
3253 Enable RMII mode for all FECs.
3254 Note that this is a global option, we can't
3255 have one FEC in standard MII mode and another in RMII mode.
3257 - CONFIG_CRC32_VERIFY
3258 Add a verify option to the crc32 command.
3261 => crc32 -v <address> <count> <crc32>
3263 Where address/count indicate a memory area
3264 and crc32 is the correct crc32 which the
3268 Add the "loopw" memory command. This only takes effect if
3269 the memory commands are activated globally (CONFIG_CMD_MEM).
3272 Add the "mdc" and "mwc" memory commands. These are cyclic
3277 This command will print 4 bytes (10,11,12,13) each 500 ms.
3279 => mwc.l 100 12345678 10
3280 This command will write 12345678 to address 100 all 10 ms.
3282 This only takes effect if the memory commands are activated
3283 globally (CONFIG_CMD_MEM).
3285 - CONFIG_SKIP_LOWLEVEL_INIT
3286 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3287 low level initializations (like setting up the memory
3288 controller) are omitted and/or U-Boot does not
3289 relocate itself into RAM.
3291 Normally this variable MUST NOT be defined. The only
3292 exception is when U-Boot is loaded (to RAM) by some
3293 other boot loader or by a debugger which performs
3294 these initializations itself.
3297 Modifies the behaviour of start.S when compiling a loader
3298 that is executed before the actual U-Boot. E.g. when
3299 compiling a NAND SPL.
3301 - CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3302 define this, if you want to read first the oob data
3303 and then the data. This is used for example on
3306 - CONFIG_USE_ARCH_MEMCPY
3307 CONFIG_USE_ARCH_MEMSET
3308 If these options are used a optimized version of memcpy/memset will
3309 be used if available. These functions may be faster under some
3310 conditions but may increase the binary size.
3312 Freescale QE/FMAN Firmware Support:
3313 -----------------------------------
3315 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3316 loading of "firmware", which is encoded in the QE firmware binary format.
3317 This firmware often needs to be loaded during U-Boot booting, so macros
3318 are used to identify the storage device (NOR flash, SPI, etc) and the address
3321 - CONFIG_SYS_QE_FMAN_FW_ADDR
3322 The address in the storage device where the firmware is located. The
3323 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3326 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3327 The maximum possible size of the firmware. The firmware binary format
3328 has a field that specifies the actual size of the firmware, but it
3329 might not be possible to read any part of the firmware unless some
3330 local storage is allocated to hold the entire firmware first.
3332 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3333 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3334 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3335 virtual address in NOR flash.
3337 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3338 Specifies that QE/FMAN firmware is located in NAND flash.
3339 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3341 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3342 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3343 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3345 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
3346 Specifies that QE/FMAN firmware is located on the primary SPI
3347 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3350 Building the Software:
3351 ======================
3353 Building U-Boot has been tested in several native build environments
3354 and in many different cross environments. Of course we cannot support
3355 all possibly existing versions of cross development tools in all
3356 (potentially obsolete) versions. In case of tool chain problems we
3357 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3358 which is extensively used to build and test U-Boot.
3360 If you are not using a native environment, it is assumed that you
3361 have GNU cross compiling tools available in your path. In this case,
3362 you must set the environment variable CROSS_COMPILE in your shell.
3363 Note that no changes to the Makefile or any other source files are
3364 necessary. For example using the ELDK on a 4xx CPU, please enter:
3366 $ CROSS_COMPILE=ppc_4xx-
3367 $ export CROSS_COMPILE
3369 Note: If you wish to generate Windows versions of the utilities in
3370 the tools directory you can use the MinGW toolchain
3371 (http://www.mingw.org). Set your HOST tools to the MinGW
3372 toolchain and execute 'make tools'. For example:
3374 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3376 Binaries such as tools/mkimage.exe will be created which can
3377 be executed on computers running Windows.
3379 U-Boot is intended to be simple to build. After installing the
3380 sources you must configure U-Boot for one specific board type. This
3385 where "NAME_config" is the name of one of the existing configu-
3386 rations; see the main Makefile for supported names.
3388 Note: for some board special configuration names may exist; check if
3389 additional information is available from the board vendor; for
3390 instance, the TQM823L systems are available without (standard)
3391 or with LCD support. You can select such additional "features"
3392 when choosing the configuration, i. e.
3395 - will configure for a plain TQM823L, i. e. no LCD support
3397 make TQM823L_LCD_config
3398 - will configure for a TQM823L with U-Boot console on LCD
3403 Finally, type "make all", and you should get some working U-Boot
3404 images ready for download to / installation on your system:
3406 - "u-boot.bin" is a raw binary image
3407 - "u-boot" is an image in ELF binary format
3408 - "u-boot.srec" is in Motorola S-Record format
3410 By default the build is performed locally and the objects are saved
3411 in the source directory. One of the two methods can be used to change
3412 this behavior and build U-Boot to some external directory:
3414 1. Add O= to the make command line invocations:
3416 make O=/tmp/build distclean
3417 make O=/tmp/build NAME_config
3418 make O=/tmp/build all
3420 2. Set environment variable BUILD_DIR to point to the desired location:
3422 export BUILD_DIR=/tmp/build
3427 Note that the command line "O=" setting overrides the BUILD_DIR environment
3431 Please be aware that the Makefiles assume you are using GNU make, so
3432 for instance on NetBSD you might need to use "gmake" instead of
3436 If the system board that you have is not listed, then you will need
3437 to port U-Boot to your hardware platform. To do this, follow these
3440 1. Add a new configuration option for your board to the toplevel
3441 "Makefile" and to the "MAKEALL" script, using the existing
3442 entries as examples. Note that here and at many other places
3443 boards and other names are listed in alphabetical sort order. Please
3445 2. Create a new directory to hold your board specific code. Add any
3446 files you need. In your board directory, you will need at least
3447 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3448 3. Create a new configuration file "include/configs/<board>.h" for
3450 3. If you're porting U-Boot to a new CPU, then also create a new
3451 directory to hold your CPU specific code. Add any files you need.
3452 4. Run "make <board>_config" with your new name.
3453 5. Type "make", and you should get a working "u-boot.srec" file
3454 to be installed on your target system.
3455 6. Debug and solve any problems that might arise.
3456 [Of course, this last step is much harder than it sounds.]
3459 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3460 ==============================================================
3462 If you have modified U-Boot sources (for instance added a new board
3463 or support for new devices, a new CPU, etc.) you are expected to
3464 provide feedback to the other developers. The feedback normally takes
3465 the form of a "patch", i. e. a context diff against a certain (latest
3466 official or latest in the git repository) version of U-Boot sources.
3468 But before you submit such a patch, please verify that your modifi-
3469 cation did not break existing code. At least make sure that *ALL* of
3470 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3471 just run the "MAKEALL" script, which will configure and build U-Boot
3472 for ALL supported system. Be warned, this will take a while. You can
3473 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3474 environment variable to the script, i. e. to use the ELDK cross tools
3477 CROSS_COMPILE=ppc_8xx- MAKEALL
3479 or to build on a native PowerPC system you can type
3481 CROSS_COMPILE=' ' MAKEALL
3483 When using the MAKEALL script, the default behaviour is to build
3484 U-Boot in the source directory. This location can be changed by
3485 setting the BUILD_DIR environment variable. Also, for each target
3486 built, the MAKEALL script saves two log files (<target>.ERR and
3487 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3488 location can be changed by setting the MAKEALL_LOGDIR environment
3489 variable. For example:
3491 export BUILD_DIR=/tmp/build
3492 export MAKEALL_LOGDIR=/tmp/log
3493 CROSS_COMPILE=ppc_8xx- MAKEALL
3495 With the above settings build objects are saved in the /tmp/build,
3496 log files are saved in the /tmp/log and the source tree remains clean
3497 during the whole build process.
3500 See also "U-Boot Porting Guide" below.
3503 Monitor Commands - Overview:
3504 ============================
3506 go - start application at address 'addr'
3507 run - run commands in an environment variable
3508 bootm - boot application image from memory
3509 bootp - boot image via network using BootP/TFTP protocol
3510 tftpboot- boot image via network using TFTP protocol
3511 and env variables "ipaddr" and "serverip"
3512 (and eventually "gatewayip")
3513 tftpput - upload a file via network using TFTP protocol
3514 rarpboot- boot image via network using RARP/TFTP protocol
3515 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3516 loads - load S-Record file over serial line
3517 loadb - load binary file over serial line (kermit mode)
3519 mm - memory modify (auto-incrementing)
3520 nm - memory modify (constant address)
3521 mw - memory write (fill)
3523 cmp - memory compare
3524 crc32 - checksum calculation
3525 i2c - I2C sub-system
3526 sspi - SPI utility commands
3527 base - print or set address offset
3528 printenv- print environment variables
3529 setenv - set environment variables
3530 saveenv - save environment variables to persistent storage
3531 protect - enable or disable FLASH write protection
3532 erase - erase FLASH memory
3533 flinfo - print FLASH memory information
3534 bdinfo - print Board Info structure
3535 iminfo - print header information for application image
3536 coninfo - print console devices and informations
3537 ide - IDE sub-system
3538 loop - infinite loop on address range
3539 loopw - infinite write loop on address range
3540 mtest - simple RAM test
3541 icache - enable or disable instruction cache
3542 dcache - enable or disable data cache
3543 reset - Perform RESET of the CPU
3544 echo - echo args to console
3545 version - print monitor version
3546 help - print online help
3547 ? - alias for 'help'
3550 Monitor Commands - Detailed Description:
3551 ========================================
3555 For now: just type "help <command>".
3558 Environment Variables:
3559 ======================
3561 U-Boot supports user configuration using Environment Variables which
3562 can be made persistent by saving to Flash memory.
3564 Environment Variables are set using "setenv", printed using
3565 "printenv", and saved to Flash using "saveenv". Using "setenv"
3566 without a value can be used to delete a variable from the
3567 environment. As long as you don't save the environment you are
3568 working with an in-memory copy. In case the Flash area containing the
3569 environment is erased by accident, a default environment is provided.
3571 Some configuration options can be set using Environment Variables.
3573 List of environment variables (most likely not complete):
3575 baudrate - see CONFIG_BAUDRATE
3577 bootdelay - see CONFIG_BOOTDELAY
3579 bootcmd - see CONFIG_BOOTCOMMAND
3581 bootargs - Boot arguments when booting an RTOS image
3583 bootfile - Name of the image to load with TFTP
3585 bootm_low - Memory range available for image processing in the bootm
3586 command can be restricted. This variable is given as
3587 a hexadecimal number and defines lowest address allowed
3588 for use by the bootm command. See also "bootm_size"
3589 environment variable. Address defined by "bootm_low" is
3590 also the base of the initial memory mapping for the Linux
3591 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3594 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3595 This variable is given as a hexadecimal number and it
3596 defines the size of the memory region starting at base
3597 address bootm_low that is accessible by the Linux kernel
3598 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3599 as the default value if it is defined, and bootm_size is
3602 bootm_size - Memory range available for image processing in the bootm
3603 command can be restricted. This variable is given as
3604 a hexadecimal number and defines the size of the region
3605 allowed for use by the bootm command. See also "bootm_low"
3606 environment variable.
3608 updatefile - Location of the software update file on a TFTP server, used
3609 by the automatic software update feature. Please refer to
3610 documentation in doc/README.update for more details.
3612 autoload - if set to "no" (any string beginning with 'n'),
3613 "bootp" will just load perform a lookup of the
3614 configuration from the BOOTP server, but not try to
3615 load any image using TFTP
3617 autostart - if set to "yes", an image loaded using the "bootp",
3618 "rarpboot", "tftpboot" or "diskboot" commands will
3619 be automatically started (by internally calling
3622 If set to "no", a standalone image passed to the
3623 "bootm" command will be copied to the load address
3624 (and eventually uncompressed), but NOT be started.
3625 This can be used to load and uncompress arbitrary
3628 fdt_high - if set this restricts the maximum address that the
3629 flattened device tree will be copied into upon boot.
3630 If this is set to the special value 0xFFFFFFFF then
3631 the fdt will not be copied at all on boot. For this
3632 to work it must reside in writable memory, have
3633 sufficient padding on the end of it for u-boot to
3634 add the information it needs into it, and the memory
3635 must be accessible by the kernel.
3637 fdtcontroladdr- if set this is the address of the control flattened
3638 device tree used by U-Boot when CONFIG_OF_CONTROL is
3641 i2cfast - (PPC405GP|PPC405EP only)
3642 if set to 'y' configures Linux I2C driver for fast
3643 mode (400kHZ). This environment variable is used in
3644 initialization code. So, for changes to be effective
3645 it must be saved and board must be reset.
3647 initrd_high - restrict positioning of initrd images:
3648 If this variable is not set, initrd images will be
3649 copied to the highest possible address in RAM; this
3650 is usually what you want since it allows for
3651 maximum initrd size. If for some reason you want to
3652 make sure that the initrd image is loaded below the
3653 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3654 variable to a value of "no" or "off" or "0".
3655 Alternatively, you can set it to a maximum upper
3656 address to use (U-Boot will still check that it
3657 does not overwrite the U-Boot stack and data).
3659 For instance, when you have a system with 16 MB
3660 RAM, and want to reserve 4 MB from use by Linux,
3661 you can do this by adding "mem=12M" to the value of
3662 the "bootargs" variable. However, now you must make
3663 sure that the initrd image is placed in the first
3664 12 MB as well - this can be done with
3666 setenv initrd_high 00c00000
3668 If you set initrd_high to 0xFFFFFFFF, this is an
3669 indication to U-Boot that all addresses are legal
3670 for the Linux kernel, including addresses in flash
3671 memory. In this case U-Boot will NOT COPY the
3672 ramdisk at all. This may be useful to reduce the
3673 boot time on your system, but requires that this
3674 feature is supported by your Linux kernel.
3676 ipaddr - IP address; needed for tftpboot command
3678 loadaddr - Default load address for commands like "bootp",
3679 "rarpboot", "tftpboot", "loadb" or "diskboot"
3681 loads_echo - see CONFIG_LOADS_ECHO
3683 serverip - TFTP server IP address; needed for tftpboot command
3685 bootretry - see CONFIG_BOOT_RETRY_TIME
3687 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3689 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3691 ethprime - controls which interface is used first.
3693 ethact - controls which interface is currently active.
3694 For example you can do the following
3696 => setenv ethact FEC
3697 => ping 192.168.0.1 # traffic sent on FEC
3698 => setenv ethact SCC
3699 => ping 10.0.0.1 # traffic sent on SCC
3701 ethrotate - When set to "no" U-Boot does not go through all
3702 available network interfaces.
3703 It just stays at the currently selected interface.
3705 netretry - When set to "no" each network operation will
3706 either succeed or fail without retrying.
3707 When set to "once" the network operation will
3708 fail when all the available network interfaces
3709 are tried once without success.
3710 Useful on scripts which control the retry operation
3713 npe_ucode - set load address for the NPE microcode
3715 tftpsrcport - If this is set, the value is used for TFTP's
3718 tftpdstport - If this is set, the value is used for TFTP's UDP
3719 destination port instead of the Well Know Port 69.
3721 tftpblocksize - Block size to use for TFTP transfers; if not set,
3722 we use the TFTP server's default block size
3724 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3725 seconds, minimum value is 1000 = 1 second). Defines
3726 when a packet is considered to be lost so it has to
3727 be retransmitted. The default is 5000 = 5 seconds.
3728 Lowering this value may make downloads succeed
3729 faster in networks with high packet loss rates or
3730 with unreliable TFTP servers.
3732 vlan - When set to a value < 4095 the traffic over
3733 Ethernet is encapsulated/received over 802.1q
3736 The following image location variables contain the location of images
3737 used in booting. The "Image" column gives the role of the image and is
3738 not an environment variable name. The other columns are environment
3739 variable names. "File Name" gives the name of the file on a TFTP
3740 server, "RAM Address" gives the location in RAM the image will be
3741 loaded to, and "Flash Location" gives the image's address in NOR
3742 flash or offset in NAND flash.
3744 *Note* - these variables don't have to be defined for all boards, some
3745 boards currenlty use other variables for these purposes, and some
3746 boards use these variables for other purposes.
3748 Image File Name RAM Address Flash Location
3749 ----- --------- ----------- --------------
3750 u-boot u-boot u-boot_addr_r u-boot_addr
3751 Linux kernel bootfile kernel_addr_r kernel_addr
3752 device tree blob fdtfile fdt_addr_r fdt_addr
3753 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3755 The following environment variables may be used and automatically
3756 updated by the network boot commands ("bootp" and "rarpboot"),
3757 depending the information provided by your boot server:
3759 bootfile - see above
3760 dnsip - IP address of your Domain Name Server
3761 dnsip2 - IP address of your secondary Domain Name Server
3762 gatewayip - IP address of the Gateway (Router) to use
3763 hostname - Target hostname
3765 netmask - Subnet Mask
3766 rootpath - Pathname of the root filesystem on the NFS server
3767 serverip - see above
3770 There are two special Environment Variables:
3772 serial# - contains hardware identification information such
3773 as type string and/or serial number
3774 ethaddr - Ethernet address
3776 These variables can be set only once (usually during manufacturing of
3777 the board). U-Boot refuses to delete or overwrite these variables
3778 once they have been set once.
3781 Further special Environment Variables:
3783 ver - Contains the U-Boot version string as printed
3784 with the "version" command. This variable is
3785 readonly (see CONFIG_VERSION_VARIABLE).
3788 Please note that changes to some configuration parameters may take
3789 only effect after the next boot (yes, that's just like Windoze :-).
3792 Command Line Parsing:
3793 =====================
3795 There are two different command line parsers available with U-Boot:
3796 the old "simple" one, and the much more powerful "hush" shell:
3798 Old, simple command line parser:
3799 --------------------------------
3801 - supports environment variables (through setenv / saveenv commands)
3802 - several commands on one line, separated by ';'
3803 - variable substitution using "... ${name} ..." syntax
3804 - special characters ('$', ';') can be escaped by prefixing with '\',
3806 setenv bootcmd bootm \${address}
3807 - You can also escape text by enclosing in single apostrophes, for example:
3808 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3813 - similar to Bourne shell, with control structures like
3814 if...then...else...fi, for...do...done; while...do...done,
3815 until...do...done, ...
3816 - supports environment ("global") variables (through setenv / saveenv
3817 commands) and local shell variables (through standard shell syntax
3818 "name=value"); only environment variables can be used with "run"
3824 (1) If a command line (or an environment variable executed by a "run"
3825 command) contains several commands separated by semicolon, and
3826 one of these commands fails, then the remaining commands will be
3829 (2) If you execute several variables with one call to run (i. e.
3830 calling run with a list of variables as arguments), any failing
3831 command will cause "run" to terminate, i. e. the remaining
3832 variables are not executed.
3834 Note for Redundant Ethernet Interfaces:
3835 =======================================
3837 Some boards come with redundant Ethernet interfaces; U-Boot supports
3838 such configurations and is capable of automatic selection of a
3839 "working" interface when needed. MAC assignment works as follows:
3841 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3842 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3843 "eth1addr" (=>eth1), "eth2addr", ...
3845 If the network interface stores some valid MAC address (for instance
3846 in SROM), this is used as default address if there is NO correspon-
3847 ding setting in the environment; if the corresponding environment
3848 variable is set, this overrides the settings in the card; that means:
3850 o If the SROM has a valid MAC address, and there is no address in the
3851 environment, the SROM's address is used.
3853 o If there is no valid address in the SROM, and a definition in the
3854 environment exists, then the value from the environment variable is
3857 o If both the SROM and the environment contain a MAC address, and
3858 both addresses are the same, this MAC address is used.
3860 o If both the SROM and the environment contain a MAC address, and the
3861 addresses differ, the value from the environment is used and a
3864 o If neither SROM nor the environment contain a MAC address, an error
3867 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3868 will be programmed into hardware as part of the initialization process. This
3869 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3870 The naming convention is as follows:
3871 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3876 U-Boot is capable of booting (and performing other auxiliary operations on)
3877 images in two formats:
3879 New uImage format (FIT)
3880 -----------------------
3882 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3883 to Flattened Device Tree). It allows the use of images with multiple
3884 components (several kernels, ramdisks, etc.), with contents protected by
3885 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3891 Old image format is based on binary files which can be basically anything,
3892 preceded by a special header; see the definitions in include/image.h for
3893 details; basically, the header defines the following image properties:
3895 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3896 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3897 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3898 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3900 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3901 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3902 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3903 * Compression Type (uncompressed, gzip, bzip2)
3909 The header is marked by a special Magic Number, and both the header
3910 and the data portions of the image are secured against corruption by
3917 Although U-Boot should support any OS or standalone application
3918 easily, the main focus has always been on Linux during the design of
3921 U-Boot includes many features that so far have been part of some
3922 special "boot loader" code within the Linux kernel. Also, any
3923 "initrd" images to be used are no longer part of one big Linux image;
3924 instead, kernel and "initrd" are separate images. This implementation
3925 serves several purposes:
3927 - the same features can be used for other OS or standalone
3928 applications (for instance: using compressed images to reduce the
3929 Flash memory footprint)
3931 - it becomes much easier to port new Linux kernel versions because
3932 lots of low-level, hardware dependent stuff are done by U-Boot
3934 - the same Linux kernel image can now be used with different "initrd"
3935 images; of course this also means that different kernel images can
3936 be run with the same "initrd". This makes testing easier (you don't
3937 have to build a new "zImage.initrd" Linux image when you just
3938 change a file in your "initrd"). Also, a field-upgrade of the
3939 software is easier now.
3945 Porting Linux to U-Boot based systems:
3946 ---------------------------------------
3948 U-Boot cannot save you from doing all the necessary modifications to
3949 configure the Linux device drivers for use with your target hardware
3950 (no, we don't intend to provide a full virtual machine interface to
3953 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3955 Just make sure your machine specific header file (for instance
3956 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3957 Information structure as we define in include/asm-<arch>/u-boot.h,
3958 and make sure that your definition of IMAP_ADDR uses the same value
3959 as your U-Boot configuration in CONFIG_SYS_IMMR.
3962 Configuring the Linux kernel:
3963 -----------------------------
3965 No specific requirements for U-Boot. Make sure you have some root
3966 device (initial ramdisk, NFS) for your target system.
3969 Building a Linux Image:
3970 -----------------------
3972 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3973 not used. If you use recent kernel source, a new build target
3974 "uImage" will exist which automatically builds an image usable by
3975 U-Boot. Most older kernels also have support for a "pImage" target,
3976 which was introduced for our predecessor project PPCBoot and uses a
3977 100% compatible format.
3986 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3987 encapsulate a compressed Linux kernel image with header information,
3988 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3990 * build a standard "vmlinux" kernel image (in ELF binary format):
3992 * convert the kernel into a raw binary image:
3994 ${CROSS_COMPILE}-objcopy -O binary \
3995 -R .note -R .comment \
3996 -S vmlinux linux.bin
3998 * compress the binary image:
4002 * package compressed binary image for U-Boot:
4004 mkimage -A ppc -O linux -T kernel -C gzip \
4005 -a 0 -e 0 -n "Linux Kernel Image" \
4006 -d linux.bin.gz uImage
4009 The "mkimage" tool can also be used to create ramdisk images for use
4010 with U-Boot, either separated from the Linux kernel image, or
4011 combined into one file. "mkimage" encapsulates the images with a 64
4012 byte header containing information about target architecture,
4013 operating system, image type, compression method, entry points, time
4014 stamp, CRC32 checksums, etc.
4016 "mkimage" can be called in two ways: to verify existing images and
4017 print the header information, or to build new images.
4019 In the first form (with "-l" option) mkimage lists the information
4020 contained in the header of an existing U-Boot image; this includes
4021 checksum verification:
4023 tools/mkimage -l image
4024 -l ==> list image header information
4026 The second form (with "-d" option) is used to build a U-Boot image
4027 from a "data file" which is used as image payload:
4029 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4030 -n name -d data_file image
4031 -A ==> set architecture to 'arch'
4032 -O ==> set operating system to 'os'
4033 -T ==> set image type to 'type'
4034 -C ==> set compression type 'comp'
4035 -a ==> set load address to 'addr' (hex)
4036 -e ==> set entry point to 'ep' (hex)
4037 -n ==> set image name to 'name'
4038 -d ==> use image data from 'datafile'
4040 Right now, all Linux kernels for PowerPC systems use the same load
4041 address (0x00000000), but the entry point address depends on the
4044 - 2.2.x kernels have the entry point at 0x0000000C,
4045 - 2.3.x and later kernels have the entry point at 0x00000000.
4047 So a typical call to build a U-Boot image would read:
4049 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4050 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4051 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4052 > examples/uImage.TQM850L
4053 Image Name: 2.4.4 kernel for TQM850L
4054 Created: Wed Jul 19 02:34:59 2000
4055 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4056 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4057 Load Address: 0x00000000
4058 Entry Point: 0x00000000
4060 To verify the contents of the image (or check for corruption):
4062 -> tools/mkimage -l examples/uImage.TQM850L
4063 Image Name: 2.4.4 kernel for TQM850L
4064 Created: Wed Jul 19 02:34:59 2000
4065 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4066 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4067 Load Address: 0x00000000
4068 Entry Point: 0x00000000
4070 NOTE: for embedded systems where boot time is critical you can trade
4071 speed for memory and install an UNCOMPRESSED image instead: this
4072 needs more space in Flash, but boots much faster since it does not
4073 need to be uncompressed:
4075 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4076 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4077 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4078 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4079 > examples/uImage.TQM850L-uncompressed
4080 Image Name: 2.4.4 kernel for TQM850L
4081 Created: Wed Jul 19 02:34:59 2000
4082 Image Type: PowerPC Linux Kernel Image (uncompressed)
4083 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4084 Load Address: 0x00000000
4085 Entry Point: 0x00000000
4088 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4089 when your kernel is intended to use an initial ramdisk:
4091 -> tools/mkimage -n 'Simple Ramdisk Image' \
4092 > -A ppc -O linux -T ramdisk -C gzip \
4093 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4094 Image Name: Simple Ramdisk Image
4095 Created: Wed Jan 12 14:01:50 2000
4096 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4097 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4098 Load Address: 0x00000000
4099 Entry Point: 0x00000000
4102 Installing a Linux Image:
4103 -------------------------
4105 To downloading a U-Boot image over the serial (console) interface,
4106 you must convert the image to S-Record format:
4108 objcopy -I binary -O srec examples/image examples/image.srec
4110 The 'objcopy' does not understand the information in the U-Boot
4111 image header, so the resulting S-Record file will be relative to
4112 address 0x00000000. To load it to a given address, you need to
4113 specify the target address as 'offset' parameter with the 'loads'
4116 Example: install the image to address 0x40100000 (which on the
4117 TQM8xxL is in the first Flash bank):
4119 => erase 40100000 401FFFFF
4125 ## Ready for S-Record download ...
4126 ~>examples/image.srec
4127 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4129 15989 15990 15991 15992
4130 [file transfer complete]
4132 ## Start Addr = 0x00000000
4135 You can check the success of the download using the 'iminfo' command;
4136 this includes a checksum verification so you can be sure no data
4137 corruption happened:
4141 ## Checking Image at 40100000 ...
4142 Image Name: 2.2.13 for initrd on TQM850L
4143 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4144 Data Size: 335725 Bytes = 327 kB = 0 MB
4145 Load Address: 00000000
4146 Entry Point: 0000000c
4147 Verifying Checksum ... OK
4153 The "bootm" command is used to boot an application that is stored in
4154 memory (RAM or Flash). In case of a Linux kernel image, the contents
4155 of the "bootargs" environment variable is passed to the kernel as
4156 parameters. You can check and modify this variable using the
4157 "printenv" and "setenv" commands:
4160 => printenv bootargs
4161 bootargs=root=/dev/ram
4163 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4165 => printenv bootargs
4166 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4169 ## Booting Linux kernel at 40020000 ...
4170 Image Name: 2.2.13 for NFS on TQM850L
4171 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4172 Data Size: 381681 Bytes = 372 kB = 0 MB
4173 Load Address: 00000000
4174 Entry Point: 0000000c
4175 Verifying Checksum ... OK
4176 Uncompressing Kernel Image ... OK
4177 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
4178 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4179 time_init: decrementer frequency = 187500000/60
4180 Calibrating delay loop... 49.77 BogoMIPS
4181 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4184 If you want to boot a Linux kernel with initial RAM disk, you pass
4185 the memory addresses of both the kernel and the initrd image (PPBCOOT
4186 format!) to the "bootm" command:
4188 => imi 40100000 40200000
4190 ## Checking Image at 40100000 ...
4191 Image Name: 2.2.13 for initrd on TQM850L
4192 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4193 Data Size: 335725 Bytes = 327 kB = 0 MB
4194 Load Address: 00000000
4195 Entry Point: 0000000c
4196 Verifying Checksum ... OK
4198 ## Checking Image at 40200000 ...
4199 Image Name: Simple Ramdisk Image
4200 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4201 Data Size: 566530 Bytes = 553 kB = 0 MB
4202 Load Address: 00000000
4203 Entry Point: 00000000
4204 Verifying Checksum ... OK
4206 => bootm 40100000 40200000
4207 ## Booting Linux kernel at 40100000 ...
4208 Image Name: 2.2.13 for initrd on TQM850L
4209 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4210 Data Size: 335725 Bytes = 327 kB = 0 MB
4211 Load Address: 00000000
4212 Entry Point: 0000000c
4213 Verifying Checksum ... OK
4214 Uncompressing Kernel Image ... OK
4215 ## Loading RAMDisk Image at 40200000 ...
4216 Image Name: Simple Ramdisk Image
4217 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4218 Data Size: 566530 Bytes = 553 kB = 0 MB
4219 Load Address: 00000000
4220 Entry Point: 00000000
4221 Verifying Checksum ... OK
4222 Loading Ramdisk ... OK
4223 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
4224 Boot arguments: root=/dev/ram
4225 time_init: decrementer frequency = 187500000/60
4226 Calibrating delay loop... 49.77 BogoMIPS
4228 RAMDISK: Compressed image found at block 0
4229 VFS: Mounted root (ext2 filesystem).
4233 Boot Linux and pass a flat device tree:
4236 First, U-Boot must be compiled with the appropriate defines. See the section
4237 titled "Linux Kernel Interface" above for a more in depth explanation. The
4238 following is an example of how to start a kernel and pass an updated
4244 oft=oftrees/mpc8540ads.dtb
4245 => tftp $oftaddr $oft
4246 Speed: 1000, full duplex
4248 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4249 Filename 'oftrees/mpc8540ads.dtb'.
4250 Load address: 0x300000
4253 Bytes transferred = 4106 (100a hex)
4254 => tftp $loadaddr $bootfile
4255 Speed: 1000, full duplex
4257 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4259 Load address: 0x200000
4260 Loading:############
4262 Bytes transferred = 1029407 (fb51f hex)
4267 => bootm $loadaddr - $oftaddr
4268 ## Booting image at 00200000 ...
4269 Image Name: Linux-2.6.17-dirty
4270 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4271 Data Size: 1029343 Bytes = 1005.2 kB
4272 Load Address: 00000000
4273 Entry Point: 00000000
4274 Verifying Checksum ... OK
4275 Uncompressing Kernel Image ... OK
4276 Booting using flat device tree at 0x300000
4277 Using MPC85xx ADS machine description
4278 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4282 More About U-Boot Image Types:
4283 ------------------------------
4285 U-Boot supports the following image types:
4287 "Standalone Programs" are directly runnable in the environment
4288 provided by U-Boot; it is expected that (if they behave
4289 well) you can continue to work in U-Boot after return from
4290 the Standalone Program.
4291 "OS Kernel Images" are usually images of some Embedded OS which
4292 will take over control completely. Usually these programs
4293 will install their own set of exception handlers, device
4294 drivers, set up the MMU, etc. - this means, that you cannot
4295 expect to re-enter U-Boot except by resetting the CPU.
4296 "RAMDisk Images" are more or less just data blocks, and their
4297 parameters (address, size) are passed to an OS kernel that is
4299 "Multi-File Images" contain several images, typically an OS
4300 (Linux) kernel image and one or more data images like
4301 RAMDisks. This construct is useful for instance when you want
4302 to boot over the network using BOOTP etc., where the boot
4303 server provides just a single image file, but you want to get
4304 for instance an OS kernel and a RAMDisk image.
4306 "Multi-File Images" start with a list of image sizes, each
4307 image size (in bytes) specified by an "uint32_t" in network
4308 byte order. This list is terminated by an "(uint32_t)0".
4309 Immediately after the terminating 0 follow the images, one by
4310 one, all aligned on "uint32_t" boundaries (size rounded up to
4311 a multiple of 4 bytes).
4313 "Firmware Images" are binary images containing firmware (like
4314 U-Boot or FPGA images) which usually will be programmed to
4317 "Script files" are command sequences that will be executed by
4318 U-Boot's command interpreter; this feature is especially
4319 useful when you configure U-Boot to use a real shell (hush)
4320 as command interpreter.
4326 One of the features of U-Boot is that you can dynamically load and
4327 run "standalone" applications, which can use some resources of
4328 U-Boot like console I/O functions or interrupt services.
4330 Two simple examples are included with the sources:
4335 'examples/hello_world.c' contains a small "Hello World" Demo
4336 application; it is automatically compiled when you build U-Boot.
4337 It's configured to run at address 0x00040004, so you can play with it
4341 ## Ready for S-Record download ...
4342 ~>examples/hello_world.srec
4343 1 2 3 4 5 6 7 8 9 10 11 ...
4344 [file transfer complete]
4346 ## Start Addr = 0x00040004
4348 => go 40004 Hello World! This is a test.
4349 ## Starting application at 0x00040004 ...
4360 Hit any key to exit ...
4362 ## Application terminated, rc = 0x0
4364 Another example, which demonstrates how to register a CPM interrupt
4365 handler with the U-Boot code, can be found in 'examples/timer.c'.
4366 Here, a CPM timer is set up to generate an interrupt every second.
4367 The interrupt service routine is trivial, just printing a '.'
4368 character, but this is just a demo program. The application can be
4369 controlled by the following keys:
4371 ? - print current values og the CPM Timer registers
4372 b - enable interrupts and start timer
4373 e - stop timer and disable interrupts
4374 q - quit application
4377 ## Ready for S-Record download ...
4378 ~>examples/timer.srec
4379 1 2 3 4 5 6 7 8 9 10 11 ...
4380 [file transfer complete]
4382 ## Start Addr = 0x00040004
4385 ## Starting application at 0x00040004 ...
4388 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4391 [q, b, e, ?] Set interval 1000000 us
4394 [q, b, e, ?] ........
4395 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4398 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4401 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4404 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4406 [q, b, e, ?] ...Stopping timer
4408 [q, b, e, ?] ## Application terminated, rc = 0x0
4414 Over time, many people have reported problems when trying to use the
4415 "minicom" terminal emulation program for serial download. I (wd)
4416 consider minicom to be broken, and recommend not to use it. Under
4417 Unix, I recommend to use C-Kermit for general purpose use (and
4418 especially for kermit binary protocol download ("loadb" command), and
4419 use "cu" for S-Record download ("loads" command).
4421 Nevertheless, if you absolutely want to use it try adding this
4422 configuration to your "File transfer protocols" section:
4424 Name Program Name U/D FullScr IO-Red. Multi
4425 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4426 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4432 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4433 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4435 Building requires a cross environment; it is known to work on
4436 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4437 need gmake since the Makefiles are not compatible with BSD make).
4438 Note that the cross-powerpc package does not install include files;
4439 attempting to build U-Boot will fail because <machine/ansi.h> is
4440 missing. This file has to be installed and patched manually:
4442 # cd /usr/pkg/cross/powerpc-netbsd/include
4444 # ln -s powerpc machine
4445 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4446 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4448 Native builds *don't* work due to incompatibilities between native
4449 and U-Boot include files.
4451 Booting assumes that (the first part of) the image booted is a
4452 stage-2 loader which in turn loads and then invokes the kernel
4453 proper. Loader sources will eventually appear in the NetBSD source
4454 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4455 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4458 Implementation Internals:
4459 =========================
4461 The following is not intended to be a complete description of every
4462 implementation detail. However, it should help to understand the
4463 inner workings of U-Boot and make it easier to port it to custom
4467 Initial Stack, Global Data:
4468 ---------------------------
4470 The implementation of U-Boot is complicated by the fact that U-Boot
4471 starts running out of ROM (flash memory), usually without access to
4472 system RAM (because the memory controller is not initialized yet).
4473 This means that we don't have writable Data or BSS segments, and BSS
4474 is not initialized as zero. To be able to get a C environment working
4475 at all, we have to allocate at least a minimal stack. Implementation
4476 options for this are defined and restricted by the CPU used: Some CPU
4477 models provide on-chip memory (like the IMMR area on MPC8xx and
4478 MPC826x processors), on others (parts of) the data cache can be
4479 locked as (mis-) used as memory, etc.
4481 Chris Hallinan posted a good summary of these issues to the
4482 U-Boot mailing list:
4484 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4485 From: "Chris Hallinan" <clh@net1plus.com>
4486 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4489 Correct me if I'm wrong, folks, but the way I understand it
4490 is this: Using DCACHE as initial RAM for Stack, etc, does not
4491 require any physical RAM backing up the cache. The cleverness
4492 is that the cache is being used as a temporary supply of
4493 necessary storage before the SDRAM controller is setup. It's
4494 beyond the scope of this list to explain the details, but you
4495 can see how this works by studying the cache architecture and
4496 operation in the architecture and processor-specific manuals.
4498 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4499 is another option for the system designer to use as an
4500 initial stack/RAM area prior to SDRAM being available. Either
4501 option should work for you. Using CS 4 should be fine if your
4502 board designers haven't used it for something that would
4503 cause you grief during the initial boot! It is frequently not
4506 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4507 with your processor/board/system design. The default value
4508 you will find in any recent u-boot distribution in
4509 walnut.h should work for you. I'd set it to a value larger
4510 than your SDRAM module. If you have a 64MB SDRAM module, set
4511 it above 400_0000. Just make sure your board has no resources
4512 that are supposed to respond to that address! That code in
4513 start.S has been around a while and should work as is when
4514 you get the config right.
4519 It is essential to remember this, since it has some impact on the C
4520 code for the initialization procedures:
4522 * Initialized global data (data segment) is read-only. Do not attempt
4525 * Do not use any uninitialized global data (or implicitely initialized
4526 as zero data - BSS segment) at all - this is undefined, initiali-
4527 zation is performed later (when relocating to RAM).
4529 * Stack space is very limited. Avoid big data buffers or things like
4532 Having only the stack as writable memory limits means we cannot use
4533 normal global data to share information beween the code. But it
4534 turned out that the implementation of U-Boot can be greatly
4535 simplified by making a global data structure (gd_t) available to all
4536 functions. We could pass a pointer to this data as argument to _all_
4537 functions, but this would bloat the code. Instead we use a feature of
4538 the GCC compiler (Global Register Variables) to share the data: we
4539 place a pointer (gd) to the global data into a register which we
4540 reserve for this purpose.
4542 When choosing a register for such a purpose we are restricted by the
4543 relevant (E)ABI specifications for the current architecture, and by
4544 GCC's implementation.
4546 For PowerPC, the following registers have specific use:
4548 R2: reserved for system use
4549 R3-R4: parameter passing and return values
4550 R5-R10: parameter passing
4551 R13: small data area pointer
4555 (U-Boot also uses R12 as internal GOT pointer. r12
4556 is a volatile register so r12 needs to be reset when
4557 going back and forth between asm and C)
4559 ==> U-Boot will use R2 to hold a pointer to the global data
4561 Note: on PPC, we could use a static initializer (since the
4562 address of the global data structure is known at compile time),
4563 but it turned out that reserving a register results in somewhat
4564 smaller code - although the code savings are not that big (on
4565 average for all boards 752 bytes for the whole U-Boot image,
4566 624 text + 127 data).
4568 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4569 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4571 ==> U-Boot will use P3 to hold a pointer to the global data
4573 On ARM, the following registers are used:
4575 R0: function argument word/integer result
4576 R1-R3: function argument word
4578 R10: stack limit (used only if stack checking if enabled)
4579 R11: argument (frame) pointer
4580 R12: temporary workspace
4583 R15: program counter
4585 ==> U-Boot will use R8 to hold a pointer to the global data
4587 On Nios II, the ABI is documented here:
4588 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4590 ==> U-Boot will use gp to hold a pointer to the global data
4592 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4593 to access small data sections, so gp is free.
4595 On NDS32, the following registers are used:
4597 R0-R1: argument/return
4599 R15: temporary register for assembler
4600 R16: trampoline register
4601 R28: frame pointer (FP)
4602 R29: global pointer (GP)
4603 R30: link register (LP)
4604 R31: stack pointer (SP)
4605 PC: program counter (PC)
4607 ==> U-Boot will use R10 to hold a pointer to the global data
4609 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4610 or current versions of GCC may "optimize" the code too much.
4615 U-Boot runs in system state and uses physical addresses, i.e. the
4616 MMU is not used either for address mapping nor for memory protection.
4618 The available memory is mapped to fixed addresses using the memory
4619 controller. In this process, a contiguous block is formed for each
4620 memory type (Flash, SDRAM, SRAM), even when it consists of several
4621 physical memory banks.
4623 U-Boot is installed in the first 128 kB of the first Flash bank (on
4624 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4625 booting and sizing and initializing DRAM, the code relocates itself
4626 to the upper end of DRAM. Immediately below the U-Boot code some
4627 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4628 configuration setting]. Below that, a structure with global Board
4629 Info data is placed, followed by the stack (growing downward).
4631 Additionally, some exception handler code is copied to the low 8 kB
4632 of DRAM (0x00000000 ... 0x00001FFF).
4634 So a typical memory configuration with 16 MB of DRAM could look like
4637 0x0000 0000 Exception Vector code
4640 0x0000 2000 Free for Application Use
4646 0x00FB FF20 Monitor Stack (Growing downward)
4647 0x00FB FFAC Board Info Data and permanent copy of global data
4648 0x00FC 0000 Malloc Arena
4651 0x00FE 0000 RAM Copy of Monitor Code
4652 ... eventually: LCD or video framebuffer
4653 ... eventually: pRAM (Protected RAM - unchanged by reset)
4654 0x00FF FFFF [End of RAM]
4657 System Initialization:
4658 ----------------------
4660 In the reset configuration, U-Boot starts at the reset entry point
4661 (on most PowerPC systems at address 0x00000100). Because of the reset
4662 configuration for CS0# this is a mirror of the onboard Flash memory.
4663 To be able to re-map memory U-Boot then jumps to its link address.
4664 To be able to implement the initialization code in C, a (small!)
4665 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4666 which provide such a feature like MPC8xx or MPC8260), or in a locked
4667 part of the data cache. After that, U-Boot initializes the CPU core,
4668 the caches and the SIU.
4670 Next, all (potentially) available memory banks are mapped using a
4671 preliminary mapping. For example, we put them on 512 MB boundaries
4672 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4673 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4674 programmed for SDRAM access. Using the temporary configuration, a
4675 simple memory test is run that determines the size of the SDRAM
4678 When there is more than one SDRAM bank, and the banks are of
4679 different size, the largest is mapped first. For equal size, the first
4680 bank (CS2#) is mapped first. The first mapping is always for address
4681 0x00000000, with any additional banks following immediately to create
4682 contiguous memory starting from 0.
4684 Then, the monitor installs itself at the upper end of the SDRAM area
4685 and allocates memory for use by malloc() and for the global Board
4686 Info data; also, the exception vector code is copied to the low RAM
4687 pages, and the final stack is set up.
4689 Only after this relocation will you have a "normal" C environment;
4690 until that you are restricted in several ways, mostly because you are
4691 running from ROM, and because the code will have to be relocated to a
4695 U-Boot Porting Guide:
4696 ----------------------
4698 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4702 int main(int argc, char *argv[])
4704 sighandler_t no_more_time;
4706 signal(SIGALRM, no_more_time);
4707 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4709 if (available_money > available_manpower) {
4710 Pay consultant to port U-Boot;
4714 Download latest U-Boot source;
4716 Subscribe to u-boot mailing list;
4719 email("Hi, I am new to U-Boot, how do I get started?");
4722 Read the README file in the top level directory;
4723 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4724 Read applicable doc/*.README;
4725 Read the source, Luke;
4726 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4729 if (available_money > toLocalCurrency ($2500))
4732 Add a lot of aggravation and time;
4734 if (a similar board exists) { /* hopefully... */
4735 cp -a board/<similar> board/<myboard>
4736 cp include/configs/<similar>.h include/configs/<myboard>.h
4738 Create your own board support subdirectory;
4739 Create your own board include/configs/<myboard>.h file;
4741 Edit new board/<myboard> files
4742 Edit new include/configs/<myboard>.h
4747 Add / modify source code;
4751 email("Hi, I am having problems...");
4753 Send patch file to the U-Boot email list;
4754 if (reasonable critiques)
4755 Incorporate improvements from email list code review;
4757 Defend code as written;
4763 void no_more_time (int sig)
4772 All contributions to U-Boot should conform to the Linux kernel
4773 coding style; see the file "Documentation/CodingStyle" and the script
4774 "scripts/Lindent" in your Linux kernel source directory.
4776 Source files originating from a different project (for example the
4777 MTD subsystem) are generally exempt from these guidelines and are not
4778 reformated to ease subsequent migration to newer versions of those
4781 Please note that U-Boot is implemented in C (and to some small parts in
4782 Assembler); no C++ is used, so please do not use C++ style comments (//)
4785 Please also stick to the following formatting rules:
4786 - remove any trailing white space
4787 - use TAB characters for indentation and vertical alignment, not spaces
4788 - make sure NOT to use DOS '\r\n' line feeds
4789 - do not add more than 2 consecutive empty lines to source files
4790 - do not add trailing empty lines to source files
4792 Submissions which do not conform to the standards may be returned
4793 with a request to reformat the changes.
4799 Since the number of patches for U-Boot is growing, we need to
4800 establish some rules. Submissions which do not conform to these rules
4801 may be rejected, even when they contain important and valuable stuff.
4803 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4805 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4806 see http://lists.denx.de/mailman/listinfo/u-boot
4808 When you send a patch, please include the following information with
4811 * For bug fixes: a description of the bug and how your patch fixes
4812 this bug. Please try to include a way of demonstrating that the
4813 patch actually fixes something.
4815 * For new features: a description of the feature and your
4818 * A CHANGELOG entry as plaintext (separate from the patch)
4820 * For major contributions, your entry to the CREDITS file
4822 * When you add support for a new board, don't forget to add this
4823 board to the MAINTAINERS file, too.
4825 * If your patch adds new configuration options, don't forget to
4826 document these in the README file.
4828 * The patch itself. If you are using git (which is *strongly*
4829 recommended) you can easily generate the patch using the
4830 "git format-patch". If you then use "git send-email" to send it to
4831 the U-Boot mailing list, you will avoid most of the common problems
4832 with some other mail clients.
4834 If you cannot use git, use "diff -purN OLD NEW". If your version of
4835 diff does not support these options, then get the latest version of
4838 The current directory when running this command shall be the parent
4839 directory of the U-Boot source tree (i. e. please make sure that
4840 your patch includes sufficient directory information for the
4843 We prefer patches as plain text. MIME attachments are discouraged,
4844 and compressed attachments must not be used.
4846 * If one logical set of modifications affects or creates several
4847 files, all these changes shall be submitted in a SINGLE patch file.
4849 * Changesets that contain different, unrelated modifications shall be
4850 submitted as SEPARATE patches, one patch per changeset.
4855 * Before sending the patch, run the MAKEALL script on your patched
4856 source tree and make sure that no errors or warnings are reported
4857 for any of the boards.
4859 * Keep your modifications to the necessary minimum: A patch
4860 containing several unrelated changes or arbitrary reformats will be
4861 returned with a request to re-formatting / split it.
4863 * If you modify existing code, make sure that your new code does not
4864 add to the memory footprint of the code ;-) Small is beautiful!
4865 When adding new features, these should compile conditionally only
4866 (using #ifdef), and the resulting code with the new feature
4867 disabled must not need more memory than the old code without your
4870 * Remember that there is a size limit of 100 kB per message on the
4871 u-boot mailing list. Bigger patches will be moderated. If they are
4872 reasonable and not too big, they will be acknowledged. But patches
4873 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob