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, board/eltec/bab7xx)
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 - Boot Delay: CONFIG_BOOTDELAY - in seconds
642 Delay before automatically booting the default image;
643 set to -1 to disable autoboot.
645 See doc/README.autoboot for these options that
646 work with CONFIG_BOOTDELAY. None are required.
647 CONFIG_BOOT_RETRY_TIME
648 CONFIG_BOOT_RETRY_MIN
649 CONFIG_AUTOBOOT_KEYED
650 CONFIG_AUTOBOOT_PROMPT
651 CONFIG_AUTOBOOT_DELAY_STR
652 CONFIG_AUTOBOOT_STOP_STR
653 CONFIG_AUTOBOOT_DELAY_STR2
654 CONFIG_AUTOBOOT_STOP_STR2
655 CONFIG_ZERO_BOOTDELAY_CHECK
656 CONFIG_RESET_TO_RETRY
660 Only needed when CONFIG_BOOTDELAY is enabled;
661 define a command string that is automatically executed
662 when no character is read on the console interface
663 within "Boot Delay" after reset.
666 This can be used to pass arguments to the bootm
667 command. The value of CONFIG_BOOTARGS goes into the
668 environment value "bootargs".
670 CONFIG_RAMBOOT and CONFIG_NFSBOOT
671 The value of these goes into the environment as
672 "ramboot" and "nfsboot" respectively, and can be used
673 as a convenience, when switching between booting from
679 When this option is #defined, the existence of the
680 environment variable "preboot" will be checked
681 immediately before starting the CONFIG_BOOTDELAY
682 countdown and/or running the auto-boot command resp.
683 entering interactive mode.
685 This feature is especially useful when "preboot" is
686 automatically generated or modified. For an example
687 see the LWMON board specific code: here "preboot" is
688 modified when the user holds down a certain
689 combination of keys on the (special) keyboard when
692 - Serial Download Echo Mode:
694 If defined to 1, all characters received during a
695 serial download (using the "loads" command) are
696 echoed back. This might be needed by some terminal
697 emulations (like "cu"), but may as well just take
698 time on others. This setting #define's the initial
699 value of the "loads_echo" environment variable.
701 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
703 Select one of the baudrates listed in
704 CONFIG_SYS_BAUDRATE_TABLE, see below.
707 Monitor commands can be included or excluded
708 from the build by using the #include files
709 "config_cmd_all.h" and #undef'ing unwanted
710 commands, or using "config_cmd_default.h"
711 and augmenting with additional #define's
714 The default command configuration includes all commands
715 except those marked below with a "*".
717 CONFIG_CMD_ASKENV * ask for env variable
718 CONFIG_CMD_BDI bdinfo
719 CONFIG_CMD_BEDBUG * Include BedBug Debugger
720 CONFIG_CMD_BMP * BMP support
721 CONFIG_CMD_BSP * Board specific commands
722 CONFIG_CMD_BOOTD bootd
723 CONFIG_CMD_CACHE * icache, dcache
724 CONFIG_CMD_CONSOLE coninfo
725 CONFIG_CMD_CRC32 * crc32
726 CONFIG_CMD_DATE * support for RTC, date/time...
727 CONFIG_CMD_DHCP * DHCP support
728 CONFIG_CMD_DIAG * Diagnostics
729 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
730 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
731 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
732 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
733 CONFIG_CMD_DTT * Digital Therm and Thermostat
734 CONFIG_CMD_ECHO echo arguments
735 CONFIG_CMD_EDITENV edit env variable
736 CONFIG_CMD_EEPROM * EEPROM read/write support
737 CONFIG_CMD_ELF * bootelf, bootvx
738 CONFIG_CMD_EXPORTENV * export the environment
739 CONFIG_CMD_SAVEENV saveenv
740 CONFIG_CMD_FDC * Floppy Disk Support
741 CONFIG_CMD_FAT * FAT partition support
742 CONFIG_CMD_FDOS * Dos diskette Support
743 CONFIG_CMD_FLASH flinfo, erase, protect
744 CONFIG_CMD_FPGA FPGA device initialization support
745 CONFIG_CMD_GO * the 'go' command (exec code)
746 CONFIG_CMD_GREPENV * search environment
747 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
748 CONFIG_CMD_I2C * I2C serial bus support
749 CONFIG_CMD_IDE * IDE harddisk support
750 CONFIG_CMD_IMI iminfo
751 CONFIG_CMD_IMLS List all found images
752 CONFIG_CMD_IMMAP * IMMR dump support
753 CONFIG_CMD_IMPORTENV * import an environment
754 CONFIG_CMD_IRQ * irqinfo
755 CONFIG_CMD_ITEST Integer/string test of 2 values
756 CONFIG_CMD_JFFS2 * JFFS2 Support
757 CONFIG_CMD_KGDB * kgdb
758 CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
759 CONFIG_CMD_LOADB loadb
760 CONFIG_CMD_LOADS loads
761 CONFIG_CMD_MD5SUM print md5 message digest
762 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
763 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
765 CONFIG_CMD_MISC Misc functions like sleep etc
766 CONFIG_CMD_MMC * MMC memory mapped support
767 CONFIG_CMD_MII * MII utility commands
768 CONFIG_CMD_MTDPARTS * MTD partition support
769 CONFIG_CMD_NAND * NAND support
770 CONFIG_CMD_NET bootp, tftpboot, rarpboot
771 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
772 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
773 CONFIG_CMD_PCI * pciinfo
774 CONFIG_CMD_PCMCIA * PCMCIA support
775 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
777 CONFIG_CMD_PORTIO * Port I/O
778 CONFIG_CMD_REGINFO * Register dump
779 CONFIG_CMD_RUN run command in env variable
780 CONFIG_CMD_SAVES * save S record dump
781 CONFIG_CMD_SCSI * SCSI Support
782 CONFIG_CMD_SDRAM * print SDRAM configuration information
783 (requires CONFIG_CMD_I2C)
784 CONFIG_CMD_SETGETDCR Support for DCR Register access
786 CONFIG_CMD_SHA1SUM print sha1 memory digest
787 (requires CONFIG_CMD_MEMORY)
788 CONFIG_CMD_SOURCE "source" command Support
789 CONFIG_CMD_SPI * SPI serial bus support
790 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
791 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
792 CONFIG_CMD_TIME * run command and report execution time
793 CONFIG_CMD_USB * USB support
794 CONFIG_CMD_CDP * Cisco Discover Protocol support
795 CONFIG_CMD_FSL * Microblaze FSL support
798 EXAMPLE: If you want all functions except of network
799 support you can write:
801 #include "config_cmd_all.h"
802 #undef CONFIG_CMD_NET
805 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
807 Note: Don't enable the "icache" and "dcache" commands
808 (configuration option CONFIG_CMD_CACHE) unless you know
809 what you (and your U-Boot users) are doing. Data
810 cache cannot be enabled on systems like the 8xx or
811 8260 (where accesses to the IMMR region must be
812 uncached), and it cannot be disabled on all other
813 systems where we (mis-) use the data cache to hold an
814 initial stack and some data.
817 XXX - this list needs to get updated!
821 If this variable is defined, U-Boot will use a device tree
822 to configure its devices, instead of relying on statically
823 compiled #defines in the board file. This option is
824 experimental and only available on a few boards. The device
825 tree is available in the global data as gd->fdt_blob.
827 U-Boot needs to get its device tree from somewhere. This can
828 be done using one of the two options below:
831 If this variable is defined, U-Boot will embed a device tree
832 binary in its image. This device tree file should be in the
833 board directory and called <soc>-<board>.dts. The binary file
834 is then picked up in board_init_f() and made available through
835 the global data structure as gd->blob.
838 If this variable is defined, U-Boot will build a device tree
839 binary. It will be called u-boot.dtb. Architecture-specific
840 code will locate it at run-time. Generally this works by:
842 cat u-boot.bin u-boot.dtb >image.bin
844 and in fact, U-Boot does this for you, creating a file called
845 u-boot-dtb.bin which is useful in the common case. You can
846 still use the individual files if you need something more
851 If this variable is defined, it enables watchdog
852 support for the SoC. There must be support in the SoC
853 specific code for a watchdog. For the 8xx and 8260
854 CPUs, the SIU Watchdog feature is enabled in the SYPCR
855 register. When supported for a specific SoC is
856 available, then no further board specific code should
860 When using a watchdog circuitry external to the used
861 SoC, then define this variable and provide board
862 specific code for the "hw_watchdog_reset" function.
865 CONFIG_VERSION_VARIABLE
866 If this variable is defined, an environment variable
867 named "ver" is created by U-Boot showing the U-Boot
868 version as printed by the "version" command.
869 This variable is readonly.
873 When CONFIG_CMD_DATE is selected, the type of the RTC
874 has to be selected, too. Define exactly one of the
877 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
878 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
879 CONFIG_RTC_MC13783 - use MC13783 RTC
880 CONFIG_RTC_MC146818 - use MC146818 RTC
881 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
882 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
883 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
884 CONFIG_RTC_DS164x - use Dallas DS164x RTC
885 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
886 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
887 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
888 CONFIG_SYS_RV3029_TCR - enable trickle charger on
891 Note that if the RTC uses I2C, then the I2C interface
892 must also be configured. See I2C Support, below.
895 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
896 CONFIG_PCA953X_INFO - enable pca953x info command
898 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
899 chip-ngpio pairs that tell the PCA953X driver the number of
900 pins supported by a particular chip.
902 Note that if the GPIO device uses I2C, then the I2C interface
903 must also be configured. See I2C Support, below.
907 When CONFIG_TIMESTAMP is selected, the timestamp
908 (date and time) of an image is printed by image
909 commands like bootm or iminfo. This option is
910 automatically enabled when you select CONFIG_CMD_DATE .
913 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
914 and/or CONFIG_ISO_PARTITION and/or CONFIG_EFI_PARTITION
916 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
917 CONFIG_CMD_SCSI) you must configure support for at
918 least one partition type as well.
921 CONFIG_IDE_RESET_ROUTINE - this is defined in several
922 board configurations files but used nowhere!
924 CONFIG_IDE_RESET - is this is defined, IDE Reset will
925 be performed by calling the function
926 ide_set_reset(int reset)
927 which has to be defined in a board specific file
932 Set this to enable ATAPI support.
937 Set this to enable support for disks larger than 137GB
938 Also look at CONFIG_SYS_64BIT_LBA.
939 Whithout these , LBA48 support uses 32bit variables and will 'only'
940 support disks up to 2.1TB.
942 CONFIG_SYS_64BIT_LBA:
943 When enabled, makes the IDE subsystem use 64bit sector addresses.
947 At the moment only there is only support for the
948 SYM53C8XX SCSI controller; define
949 CONFIG_SCSI_SYM53C8XX to enable it.
951 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
952 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
953 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
954 maximum numbers of LUNs, SCSI ID's and target
956 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
958 - NETWORK Support (PCI):
960 Support for Intel 8254x gigabit chips.
962 CONFIG_E1000_FALLBACK_MAC
963 default MAC for empty EEPROM after production.
966 Support for Intel 82557/82559/82559ER chips.
967 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
968 write routine for first time initialisation.
971 Support for Digital 2114x chips.
972 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
973 modem chip initialisation (KS8761/QS6611).
976 Support for National dp83815 chips.
979 Support for National dp8382[01] gigabit chips.
981 - NETWORK Support (other):
983 CONFIG_DRIVER_AT91EMAC
984 Support for AT91RM9200 EMAC.
987 Define this to use reduced MII inteface
989 CONFIG_DRIVER_AT91EMAC_QUIET
990 If this defined, the driver is quiet.
991 The driver doen't show link status messages.
993 CONFIG_DRIVER_LAN91C96
994 Support for SMSC's LAN91C96 chips.
997 Define this to hold the physical address
998 of the LAN91C96's I/O space
1000 CONFIG_LAN91C96_USE_32_BIT
1001 Define this to enable 32 bit addressing
1003 CONFIG_DRIVER_SMC91111
1004 Support for SMSC's LAN91C111 chip
1006 CONFIG_SMC91111_BASE
1007 Define this to hold the physical address
1008 of the device (I/O space)
1010 CONFIG_SMC_USE_32_BIT
1011 Define this if data bus is 32 bits
1013 CONFIG_SMC_USE_IOFUNCS
1014 Define this to use i/o functions instead of macros
1015 (some hardware wont work with macros)
1018 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1020 CONFIG_FTGMAC100_EGIGA
1021 Define this to use GE link update with gigabit PHY.
1022 Define this if FTGMAC100 is connected to gigabit PHY.
1023 If your system has 10/100 PHY only, it might not occur
1024 wrong behavior. Because PHY usually return timeout or
1025 useless data when polling gigabit status and gigabit
1026 control registers. This behavior won't affect the
1027 correctnessof 10/100 link speed update.
1030 Support for SMSC's LAN911x and LAN921x chips
1033 Define this to hold the physical address
1034 of the device (I/O space)
1036 CONFIG_SMC911X_32_BIT
1037 Define this if data bus is 32 bits
1039 CONFIG_SMC911X_16_BIT
1040 Define this if data bus is 16 bits. If your processor
1041 automatically converts one 32 bit word to two 16 bit
1042 words you may also try CONFIG_SMC911X_32_BIT.
1045 Support for Renesas on-chip Ethernet controller
1047 CONFIG_SH_ETHER_USE_PORT
1048 Define the number of ports to be used
1050 CONFIG_SH_ETHER_PHY_ADDR
1051 Define the ETH PHY's address
1053 CONFIG_SH_ETHER_CACHE_WRITEBACK
1054 If this option is set, the driver enables cache flush.
1057 At the moment only the UHCI host controller is
1058 supported (PIP405, MIP405, MPC5200); define
1059 CONFIG_USB_UHCI to enable it.
1060 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1061 and define CONFIG_USB_STORAGE to enable the USB
1064 Supported are USB Keyboards and USB Floppy drives
1066 MPC5200 USB requires additional defines:
1068 for 528 MHz Clock: 0x0001bbbb
1072 for differential drivers: 0x00001000
1073 for single ended drivers: 0x00005000
1074 for differential drivers on PSC3: 0x00000100
1075 for single ended drivers on PSC3: 0x00004100
1076 CONFIG_SYS_USB_EVENT_POLL
1077 May be defined to allow interrupt polling
1078 instead of using asynchronous interrupts
1081 Define the below if you wish to use the USB console.
1082 Once firmware is rebuilt from a serial console issue the
1083 command "setenv stdin usbtty; setenv stdout usbtty" and
1084 attach your USB cable. The Unix command "dmesg" should print
1085 it has found a new device. The environment variable usbtty
1086 can be set to gserial or cdc_acm to enable your device to
1087 appear to a USB host as a Linux gserial device or a
1088 Common Device Class Abstract Control Model serial device.
1089 If you select usbtty = gserial you should be able to enumerate
1091 # modprobe usbserial vendor=0xVendorID product=0xProductID
1092 else if using cdc_acm, simply setting the environment
1093 variable usbtty to be cdc_acm should suffice. The following
1094 might be defined in YourBoardName.h
1097 Define this to build a UDC device
1100 Define this to have a tty type of device available to
1101 talk to the UDC device
1103 CONFIG_SYS_CONSOLE_IS_IN_ENV
1104 Define this if you want stdin, stdout &/or stderr to
1108 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1109 Derive USB clock from external clock "blah"
1110 - CONFIG_SYS_USB_EXTC_CLK 0x02
1112 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1113 Derive USB clock from brgclk
1114 - CONFIG_SYS_USB_BRG_CLK 0x04
1116 If you have a USB-IF assigned VendorID then you may wish to
1117 define your own vendor specific values either in BoardName.h
1118 or directly in usbd_vendor_info.h. If you don't define
1119 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1120 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1121 should pretend to be a Linux device to it's target host.
1123 CONFIG_USBD_MANUFACTURER
1124 Define this string as the name of your company for
1125 - CONFIG_USBD_MANUFACTURER "my company"
1127 CONFIG_USBD_PRODUCT_NAME
1128 Define this string as the name of your product
1129 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1131 CONFIG_USBD_VENDORID
1132 Define this as your assigned Vendor ID from the USB
1133 Implementors Forum. This *must* be a genuine Vendor ID
1134 to avoid polluting the USB namespace.
1135 - CONFIG_USBD_VENDORID 0xFFFF
1137 CONFIG_USBD_PRODUCTID
1138 Define this as the unique Product ID
1140 - CONFIG_USBD_PRODUCTID 0xFFFF
1144 The MMC controller on the Intel PXA is supported. To
1145 enable this define CONFIG_MMC. The MMC can be
1146 accessed from the boot prompt by mapping the device
1147 to physical memory similar to flash. Command line is
1148 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1149 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1152 Support for Renesas on-chip MMCIF controller
1154 CONFIG_SH_MMCIF_ADDR
1155 Define the base address of MMCIF registers
1158 Define the clock frequency for MMCIF
1160 - Journaling Flash filesystem support:
1161 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1162 CONFIG_JFFS2_NAND_DEV
1163 Define these for a default partition on a NAND device
1165 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1166 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1167 Define these for a default partition on a NOR device
1169 CONFIG_SYS_JFFS_CUSTOM_PART
1170 Define this to create an own partition. You have to provide a
1171 function struct part_info* jffs2_part_info(int part_num)
1173 If you define only one JFFS2 partition you may also want to
1174 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1175 to disable the command chpart. This is the default when you
1176 have not defined a custom partition
1178 - FAT(File Allocation Table) filesystem write function support:
1180 Support for saving memory data as a file
1181 in FAT formatted partition
1186 Define this to enable standard (PC-Style) keyboard
1190 Standard PC keyboard driver with US (is default) and
1191 GERMAN key layout (switch via environment 'keymap=de') support.
1192 Export function i8042_kbd_init, i8042_tstc and i8042_getc
1193 for cfb_console. Supports cursor blinking.
1198 Define this to enable video support (for output to
1201 CONFIG_VIDEO_CT69000
1203 Enable Chips & Technologies 69000 Video chip
1205 CONFIG_VIDEO_SMI_LYNXEM
1206 Enable Silicon Motion SMI 712/710/810 Video chip. The
1207 video output is selected via environment 'videoout'
1208 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1211 For the CT69000 and SMI_LYNXEM drivers, videomode is
1212 selected via environment 'videomode'. Two different ways
1214 - "videomode=num" 'num' is a standard LiLo mode numbers.
1215 Following standard modes are supported (* is default):
1217 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1218 -------------+---------------------------------------------
1219 8 bits | 0x301* 0x303 0x305 0x161 0x307
1220 15 bits | 0x310 0x313 0x316 0x162 0x319
1221 16 bits | 0x311 0x314 0x317 0x163 0x31A
1222 24 bits | 0x312 0x315 0x318 ? 0x31B
1223 -------------+---------------------------------------------
1224 (i.e. setenv videomode 317; saveenv; reset;)
1226 - "videomode=bootargs" all the video parameters are parsed
1227 from the bootargs. (See drivers/video/videomodes.c)
1230 CONFIG_VIDEO_SED13806
1231 Enable Epson SED13806 driver. This driver supports 8bpp
1232 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1233 or CONFIG_VIDEO_SED13806_16BPP
1236 Enable the Freescale DIU video driver. Reference boards for
1237 SOCs that have a DIU should define this macro to enable DIU
1238 support, and should also define these other macros:
1244 CONFIG_VIDEO_SW_CURSOR
1245 CONFIG_VGA_AS_SINGLE_DEVICE
1247 CONFIG_VIDEO_BMP_LOGO
1249 The DIU driver will look for the 'video-mode' environment
1250 variable, and if defined, enable the DIU as a console during
1251 boot. See the documentation file README.video for a
1252 description of this variable.
1257 Define this to enable a custom keyboard support.
1258 This simply calls drv_keyboard_init() which must be
1259 defined in your board-specific files.
1260 The only board using this so far is RBC823.
1262 - LCD Support: CONFIG_LCD
1264 Define this to enable LCD support (for output to LCD
1265 display); also select one of the supported displays
1266 by defining one of these:
1270 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1272 CONFIG_NEC_NL6448AC33:
1274 NEC NL6448AC33-18. Active, color, single scan.
1276 CONFIG_NEC_NL6448BC20
1278 NEC NL6448BC20-08. 6.5", 640x480.
1279 Active, color, single scan.
1281 CONFIG_NEC_NL6448BC33_54
1283 NEC NL6448BC33-54. 10.4", 640x480.
1284 Active, color, single scan.
1288 Sharp 320x240. Active, color, single scan.
1289 It isn't 16x9, and I am not sure what it is.
1291 CONFIG_SHARP_LQ64D341
1293 Sharp LQ64D341 display, 640x480.
1294 Active, color, single scan.
1298 HLD1045 display, 640x480.
1299 Active, color, single scan.
1303 Optrex CBL50840-2 NF-FW 99 22 M5
1305 Hitachi LMG6912RPFC-00T
1309 320x240. Black & white.
1311 Normally display is black on white background; define
1312 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1314 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1316 If this option is set, the environment is checked for
1317 a variable "splashimage". If found, the usual display
1318 of logo, copyright and system information on the LCD
1319 is suppressed and the BMP image at the address
1320 specified in "splashimage" is loaded instead. The
1321 console is redirected to the "nulldev", too. This
1322 allows for a "silent" boot where a splash screen is
1323 loaded very quickly after power-on.
1325 CONFIG_SPLASH_SCREEN_ALIGN
1327 If this option is set the splash image can be freely positioned
1328 on the screen. Environment variable "splashpos" specifies the
1329 position as "x,y". If a positive number is given it is used as
1330 number of pixel from left/top. If a negative number is given it
1331 is used as number of pixel from right/bottom. You can also
1332 specify 'm' for centering the image.
1335 setenv splashpos m,m
1336 => image at center of screen
1338 setenv splashpos 30,20
1339 => image at x = 30 and y = 20
1341 setenv splashpos -10,m
1342 => vertically centered image
1343 at x = dspWidth - bmpWidth - 9
1345 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1347 If this option is set, additionally to standard BMP
1348 images, gzipped BMP images can be displayed via the
1349 splashscreen support or the bmp command.
1351 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1353 If this option is set, 8-bit RLE compressed BMP images
1354 can be displayed via the splashscreen support or the
1357 - Compression support:
1360 If this option is set, support for bzip2 compressed
1361 images is included. If not, only uncompressed and gzip
1362 compressed images are supported.
1364 NOTE: the bzip2 algorithm requires a lot of RAM, so
1365 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1370 If this option is set, support for lzma compressed
1373 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1374 requires an amount of dynamic memory that is given by the
1377 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1379 Where lc and lp stand for, respectively, Literal context bits
1380 and Literal pos bits.
1382 This value is upper-bounded by 14MB in the worst case. Anyway,
1383 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1384 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1385 a very small buffer.
1387 Use the lzmainfo tool to determinate the lc and lp values and
1388 then calculate the amount of needed dynamic memory (ensuring
1389 the appropriate CONFIG_SYS_MALLOC_LEN value).
1394 The address of PHY on MII bus.
1396 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1398 The clock frequency of the MII bus
1402 If this option is set, support for speed/duplex
1403 detection of gigabit PHY is included.
1405 CONFIG_PHY_RESET_DELAY
1407 Some PHY like Intel LXT971A need extra delay after
1408 reset before any MII register access is possible.
1409 For such PHY, set this option to the usec delay
1410 required. (minimum 300usec for LXT971A)
1412 CONFIG_PHY_CMD_DELAY (ppc4xx)
1414 Some PHY like Intel LXT971A need extra delay after
1415 command issued before MII status register can be read
1425 Define a default value for Ethernet address to use
1426 for the respective Ethernet interface, in case this
1427 is not determined automatically.
1432 Define a default value for the IP address to use for
1433 the default Ethernet interface, in case this is not
1434 determined through e.g. bootp.
1435 (Environment variable "ipaddr")
1437 - Server IP address:
1440 Defines a default value for the IP address of a TFTP
1441 server to contact when using the "tftboot" command.
1442 (Environment variable "serverip")
1444 CONFIG_KEEP_SERVERADDR
1446 Keeps the server's MAC address, in the env 'serveraddr'
1447 for passing to bootargs (like Linux's netconsole option)
1449 - Gateway IP address:
1452 Defines a default value for the IP address of the
1453 default router where packets to other networks are
1455 (Environment variable "gatewayip")
1460 Defines a default value for the subnet mask (or
1461 routing prefix) which is used to determine if an IP
1462 address belongs to the local subnet or needs to be
1463 forwarded through a router.
1464 (Environment variable "netmask")
1466 - Multicast TFTP Mode:
1469 Defines whether you want to support multicast TFTP as per
1470 rfc-2090; for example to work with atftp. Lets lots of targets
1471 tftp down the same boot image concurrently. Note: the Ethernet
1472 driver in use must provide a function: mcast() to join/leave a
1475 - BOOTP Recovery Mode:
1476 CONFIG_BOOTP_RANDOM_DELAY
1478 If you have many targets in a network that try to
1479 boot using BOOTP, you may want to avoid that all
1480 systems send out BOOTP requests at precisely the same
1481 moment (which would happen for instance at recovery
1482 from a power failure, when all systems will try to
1483 boot, thus flooding the BOOTP server. Defining
1484 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1485 inserted before sending out BOOTP requests. The
1486 following delays are inserted then:
1488 1st BOOTP request: delay 0 ... 1 sec
1489 2nd BOOTP request: delay 0 ... 2 sec
1490 3rd BOOTP request: delay 0 ... 4 sec
1492 BOOTP requests: delay 0 ... 8 sec
1494 - DHCP Advanced Options:
1495 You can fine tune the DHCP functionality by defining
1496 CONFIG_BOOTP_* symbols:
1498 CONFIG_BOOTP_SUBNETMASK
1499 CONFIG_BOOTP_GATEWAY
1500 CONFIG_BOOTP_HOSTNAME
1501 CONFIG_BOOTP_NISDOMAIN
1502 CONFIG_BOOTP_BOOTPATH
1503 CONFIG_BOOTP_BOOTFILESIZE
1506 CONFIG_BOOTP_SEND_HOSTNAME
1507 CONFIG_BOOTP_NTPSERVER
1508 CONFIG_BOOTP_TIMEOFFSET
1509 CONFIG_BOOTP_VENDOREX
1511 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1512 environment variable, not the BOOTP server.
1514 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1515 serverip from a DHCP server, it is possible that more
1516 than one DNS serverip is offered to the client.
1517 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1518 serverip will be stored in the additional environment
1519 variable "dnsip2". The first DNS serverip is always
1520 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1523 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1524 to do a dynamic update of a DNS server. To do this, they
1525 need the hostname of the DHCP requester.
1526 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1527 of the "hostname" environment variable is passed as
1528 option 12 to the DHCP server.
1530 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1532 A 32bit value in microseconds for a delay between
1533 receiving a "DHCP Offer" and sending the "DHCP Request".
1534 This fixes a problem with certain DHCP servers that don't
1535 respond 100% of the time to a "DHCP request". E.g. On an
1536 AT91RM9200 processor running at 180MHz, this delay needed
1537 to be *at least* 15,000 usec before a Windows Server 2003
1538 DHCP server would reply 100% of the time. I recommend at
1539 least 50,000 usec to be safe. The alternative is to hope
1540 that one of the retries will be successful but note that
1541 the DHCP timeout and retry process takes a longer than
1545 CONFIG_CDP_DEVICE_ID
1547 The device id used in CDP trigger frames.
1549 CONFIG_CDP_DEVICE_ID_PREFIX
1551 A two character string which is prefixed to the MAC address
1556 A printf format string which contains the ascii name of
1557 the port. Normally is set to "eth%d" which sets
1558 eth0 for the first Ethernet, eth1 for the second etc.
1560 CONFIG_CDP_CAPABILITIES
1562 A 32bit integer which indicates the device capabilities;
1563 0x00000010 for a normal host which does not forwards.
1567 An ascii string containing the version of the software.
1571 An ascii string containing the name of the platform.
1575 A 32bit integer sent on the trigger.
1577 CONFIG_CDP_POWER_CONSUMPTION
1579 A 16bit integer containing the power consumption of the
1580 device in .1 of milliwatts.
1582 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1584 A byte containing the id of the VLAN.
1586 - Status LED: CONFIG_STATUS_LED
1588 Several configurations allow to display the current
1589 status using a LED. For instance, the LED will blink
1590 fast while running U-Boot code, stop blinking as
1591 soon as a reply to a BOOTP request was received, and
1592 start blinking slow once the Linux kernel is running
1593 (supported by a status LED driver in the Linux
1594 kernel). Defining CONFIG_STATUS_LED enables this
1597 - CAN Support: CONFIG_CAN_DRIVER
1599 Defining CONFIG_CAN_DRIVER enables CAN driver support
1600 on those systems that support this (optional)
1601 feature, like the TQM8xxL modules.
1603 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1605 These enable I2C serial bus commands. Defining either of
1606 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1607 include the appropriate I2C driver for the selected CPU.
1609 This will allow you to use i2c commands at the u-boot
1610 command line (as long as you set CONFIG_CMD_I2C in
1611 CONFIG_COMMANDS) and communicate with i2c based realtime
1612 clock chips. See common/cmd_i2c.c for a description of the
1613 command line interface.
1615 CONFIG_HARD_I2C selects a hardware I2C controller.
1617 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1618 bit-banging) driver instead of CPM or similar hardware
1621 There are several other quantities that must also be
1622 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1624 In both cases you will need to define CONFIG_SYS_I2C_SPEED
1625 to be the frequency (in Hz) at which you wish your i2c bus
1626 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
1627 the CPU's i2c node address).
1629 Now, the u-boot i2c code for the mpc8xx
1630 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
1631 and so its address should therefore be cleared to 0 (See,
1632 eg, MPC823e User's Manual p.16-473). So, set
1633 CONFIG_SYS_I2C_SLAVE to 0.
1635 CONFIG_SYS_I2C_INIT_MPC5XXX
1637 When a board is reset during an i2c bus transfer
1638 chips might think that the current transfer is still
1639 in progress. Reset the slave devices by sending start
1640 commands until the slave device responds.
1642 That's all that's required for CONFIG_HARD_I2C.
1644 If you use the software i2c interface (CONFIG_SOFT_I2C)
1645 then the following macros need to be defined (examples are
1646 from include/configs/lwmon.h):
1650 (Optional). Any commands necessary to enable the I2C
1651 controller or configure ports.
1653 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1657 (Only for MPC8260 CPU). The I/O port to use (the code
1658 assumes both bits are on the same port). Valid values
1659 are 0..3 for ports A..D.
1663 The code necessary to make the I2C data line active
1664 (driven). If the data line is open collector, this
1667 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1671 The code necessary to make the I2C data line tri-stated
1672 (inactive). If the data line is open collector, this
1675 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1679 Code that returns TRUE if the I2C data line is high,
1682 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1686 If <bit> is TRUE, sets the I2C data line high. If it
1687 is FALSE, it clears it (low).
1689 eg: #define I2C_SDA(bit) \
1690 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1691 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1695 If <bit> is TRUE, sets the I2C clock line high. If it
1696 is FALSE, it clears it (low).
1698 eg: #define I2C_SCL(bit) \
1699 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1700 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1704 This delay is invoked four times per clock cycle so this
1705 controls the rate of data transfer. The data rate thus
1706 is 1 / (I2C_DELAY * 4). Often defined to be something
1709 #define I2C_DELAY udelay(2)
1711 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1713 If your arch supports the generic GPIO framework (asm/gpio.h),
1714 then you may alternatively define the two GPIOs that are to be
1715 used as SCL / SDA. Any of the previous I2C_xxx macros will
1716 have GPIO-based defaults assigned to them as appropriate.
1718 You should define these to the GPIO value as given directly to
1719 the generic GPIO functions.
1721 CONFIG_SYS_I2C_INIT_BOARD
1723 When a board is reset during an i2c bus transfer
1724 chips might think that the current transfer is still
1725 in progress. On some boards it is possible to access
1726 the i2c SCLK line directly, either by using the
1727 processor pin as a GPIO or by having a second pin
1728 connected to the bus. If this option is defined a
1729 custom i2c_init_board() routine in boards/xxx/board.c
1730 is run early in the boot sequence.
1732 CONFIG_SYS_I2C_BOARD_LATE_INIT
1734 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
1735 defined a custom i2c_board_late_init() routine in
1736 boards/xxx/board.c is run AFTER the operations in i2c_init()
1737 is completed. This callpoint can be used to unreset i2c bus
1738 using CPU i2c controller register accesses for CPUs whose i2c
1739 controller provide such a method. It is called at the end of
1740 i2c_init() to allow i2c_init operations to setup the i2c bus
1741 controller on the CPU (e.g. setting bus speed & slave address).
1743 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1745 This option enables configuration of bi_iic_fast[] flags
1746 in u-boot bd_info structure based on u-boot environment
1747 variable "i2cfast". (see also i2cfast)
1749 CONFIG_I2C_MULTI_BUS
1751 This option allows the use of multiple I2C buses, each of which
1752 must have a controller. At any point in time, only one bus is
1753 active. To switch to a different bus, use the 'i2c dev' command.
1754 Note that bus numbering is zero-based.
1756 CONFIG_SYS_I2C_NOPROBES
1758 This option specifies a list of I2C devices that will be skipped
1759 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1760 is set, specify a list of bus-device pairs. Otherwise, specify
1761 a 1D array of device addresses
1764 #undef CONFIG_I2C_MULTI_BUS
1765 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1767 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1769 #define CONFIG_I2C_MULTI_BUS
1770 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1772 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1774 CONFIG_SYS_SPD_BUS_NUM
1776 If defined, then this indicates the I2C bus number for DDR SPD.
1777 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1779 CONFIG_SYS_RTC_BUS_NUM
1781 If defined, then this indicates the I2C bus number for the RTC.
1782 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1784 CONFIG_SYS_DTT_BUS_NUM
1786 If defined, then this indicates the I2C bus number for the DTT.
1787 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1789 CONFIG_SYS_I2C_DTT_ADDR:
1791 If defined, specifies the I2C address of the DTT device.
1792 If not defined, then U-Boot uses predefined value for
1793 specified DTT device.
1797 Define this option if you want to use Freescale's I2C driver in
1798 drivers/i2c/fsl_i2c.c.
1802 Define this option if you have I2C devices reached over 1 .. n
1803 I2C Muxes like the pca9544a. This option addes a new I2C
1804 Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a
1805 new I2C Bus to the existing I2C Busses. If you select the
1806 new Bus with "i2c dev", u-bbot sends first the commandos for
1807 the muxes to activate this new "bus".
1809 CONFIG_I2C_MULTI_BUS must be also defined, to use this
1813 Adding a new I2C Bus reached over 2 pca9544a muxes
1814 The First mux with address 70 and channel 6
1815 The Second mux with address 71 and channel 4
1817 => i2c bus pca9544a:70:6:pca9544a:71:4
1819 Use the "i2c bus" command without parameter, to get a list
1820 of I2C Busses with muxes:
1823 Busses reached over muxes:
1825 reached over Mux(es):
1828 reached over Mux(es):
1833 If you now switch to the new I2C Bus 3 with "i2c dev 3"
1834 u-boot first sends the command to the mux@70 to enable
1835 channel 6, and then the command to the mux@71 to enable
1838 After that, you can use the "normal" i2c commands as
1839 usual to communicate with your I2C devices behind
1842 This option is actually implemented for the bitbanging
1843 algorithm in common/soft_i2c.c and for the Hardware I2C
1844 Bus on the MPC8260. But it should be not so difficult
1845 to add this option to other architectures.
1847 CONFIG_SOFT_I2C_READ_REPEATED_START
1849 defining this will force the i2c_read() function in
1850 the soft_i2c driver to perform an I2C repeated start
1851 between writing the address pointer and reading the
1852 data. If this define is omitted the default behaviour
1853 of doing a stop-start sequence will be used. Most I2C
1854 devices can use either method, but some require one or
1857 - SPI Support: CONFIG_SPI
1859 Enables SPI driver (so far only tested with
1860 SPI EEPROM, also an instance works with Crystal A/D and
1861 D/As on the SACSng board)
1865 Enables the driver for SPI controller on SuperH. Currently
1866 only SH7757 is supported.
1870 Enables extended (16-bit) SPI EEPROM addressing.
1871 (symmetrical to CONFIG_I2C_X)
1875 Enables a software (bit-bang) SPI driver rather than
1876 using hardware support. This is a general purpose
1877 driver that only requires three general I/O port pins
1878 (two outputs, one input) to function. If this is
1879 defined, the board configuration must define several
1880 SPI configuration items (port pins to use, etc). For
1881 an example, see include/configs/sacsng.h.
1885 Enables a hardware SPI driver for general-purpose reads
1886 and writes. As with CONFIG_SOFT_SPI, the board configuration
1887 must define a list of chip-select function pointers.
1888 Currently supported on some MPC8xxx processors. For an
1889 example, see include/configs/mpc8349emds.h.
1893 Enables the driver for the SPI controllers on i.MX and MXC
1894 SoCs. Currently only i.MX31 is supported.
1896 - FPGA Support: CONFIG_FPGA
1898 Enables FPGA subsystem.
1900 CONFIG_FPGA_<vendor>
1902 Enables support for specific chip vendors.
1905 CONFIG_FPGA_<family>
1907 Enables support for FPGA family.
1908 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1912 Specify the number of FPGA devices to support.
1914 CONFIG_SYS_FPGA_PROG_FEEDBACK
1916 Enable printing of hash marks during FPGA configuration.
1918 CONFIG_SYS_FPGA_CHECK_BUSY
1920 Enable checks on FPGA configuration interface busy
1921 status by the configuration function. This option
1922 will require a board or device specific function to
1927 If defined, a function that provides delays in the FPGA
1928 configuration driver.
1930 CONFIG_SYS_FPGA_CHECK_CTRLC
1931 Allow Control-C to interrupt FPGA configuration
1933 CONFIG_SYS_FPGA_CHECK_ERROR
1935 Check for configuration errors during FPGA bitfile
1936 loading. For example, abort during Virtex II
1937 configuration if the INIT_B line goes low (which
1938 indicated a CRC error).
1940 CONFIG_SYS_FPGA_WAIT_INIT
1942 Maximum time to wait for the INIT_B line to deassert
1943 after PROB_B has been deasserted during a Virtex II
1944 FPGA configuration sequence. The default time is 500
1947 CONFIG_SYS_FPGA_WAIT_BUSY
1949 Maximum time to wait for BUSY to deassert during
1950 Virtex II FPGA configuration. The default is 5 ms.
1952 CONFIG_SYS_FPGA_WAIT_CONFIG
1954 Time to wait after FPGA configuration. The default is
1957 - Configuration Management:
1960 If defined, this string will be added to the U-Boot
1961 version information (U_BOOT_VERSION)
1963 - Vendor Parameter Protection:
1965 U-Boot considers the values of the environment
1966 variables "serial#" (Board Serial Number) and
1967 "ethaddr" (Ethernet Address) to be parameters that
1968 are set once by the board vendor / manufacturer, and
1969 protects these variables from casual modification by
1970 the user. Once set, these variables are read-only,
1971 and write or delete attempts are rejected. You can
1972 change this behaviour:
1974 If CONFIG_ENV_OVERWRITE is #defined in your config
1975 file, the write protection for vendor parameters is
1976 completely disabled. Anybody can change or delete
1979 Alternatively, if you #define _both_ CONFIG_ETHADDR
1980 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1981 Ethernet address is installed in the environment,
1982 which can be changed exactly ONCE by the user. [The
1983 serial# is unaffected by this, i. e. it remains
1989 Define this variable to enable the reservation of
1990 "protected RAM", i. e. RAM which is not overwritten
1991 by U-Boot. Define CONFIG_PRAM to hold the number of
1992 kB you want to reserve for pRAM. You can overwrite
1993 this default value by defining an environment
1994 variable "pram" to the number of kB you want to
1995 reserve. Note that the board info structure will
1996 still show the full amount of RAM. If pRAM is
1997 reserved, a new environment variable "mem" will
1998 automatically be defined to hold the amount of
1999 remaining RAM in a form that can be passed as boot
2000 argument to Linux, for instance like that:
2002 setenv bootargs ... mem=\${mem}
2005 This way you can tell Linux not to use this memory,
2006 either, which results in a memory region that will
2007 not be affected by reboots.
2009 *WARNING* If your board configuration uses automatic
2010 detection of the RAM size, you must make sure that
2011 this memory test is non-destructive. So far, the
2012 following board configurations are known to be
2015 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
2016 HERMES, IP860, RPXlite, LWMON, LANTEC,
2022 Define this variable to stop the system in case of a
2023 fatal error, so that you have to reset it manually.
2024 This is probably NOT a good idea for an embedded
2025 system where you want the system to reboot
2026 automatically as fast as possible, but it may be
2027 useful during development since you can try to debug
2028 the conditions that lead to the situation.
2030 CONFIG_NET_RETRY_COUNT
2032 This variable defines the number of retries for
2033 network operations like ARP, RARP, TFTP, or BOOTP
2034 before giving up the operation. If not defined, a
2035 default value of 5 is used.
2039 Timeout waiting for an ARP reply in milliseconds.
2041 - Command Interpreter:
2042 CONFIG_AUTO_COMPLETE
2044 Enable auto completion of commands using TAB.
2046 Note that this feature has NOT been implemented yet
2047 for the "hush" shell.
2050 CONFIG_SYS_HUSH_PARSER
2052 Define this variable to enable the "hush" shell (from
2053 Busybox) as command line interpreter, thus enabling
2054 powerful command line syntax like
2055 if...then...else...fi conditionals or `&&' and '||'
2056 constructs ("shell scripts").
2058 If undefined, you get the old, much simpler behaviour
2059 with a somewhat smaller memory footprint.
2062 CONFIG_SYS_PROMPT_HUSH_PS2
2064 This defines the secondary prompt string, which is
2065 printed when the command interpreter needs more input
2066 to complete a command. Usually "> ".
2070 In the current implementation, the local variables
2071 space and global environment variables space are
2072 separated. Local variables are those you define by
2073 simply typing `name=value'. To access a local
2074 variable later on, you have write `$name' or
2075 `${name}'; to execute the contents of a variable
2076 directly type `$name' at the command prompt.
2078 Global environment variables are those you use
2079 setenv/printenv to work with. To run a command stored
2080 in such a variable, you need to use the run command,
2081 and you must not use the '$' sign to access them.
2083 To store commands and special characters in a
2084 variable, please use double quotation marks
2085 surrounding the whole text of the variable, instead
2086 of the backslashes before semicolons and special
2089 - Commandline Editing and History:
2090 CONFIG_CMDLINE_EDITING
2092 Enable editing and History functions for interactive
2093 commandline input operations
2095 - Default Environment:
2096 CONFIG_EXTRA_ENV_SETTINGS
2098 Define this to contain any number of null terminated
2099 strings (variable = value pairs) that will be part of
2100 the default environment compiled into the boot image.
2102 For example, place something like this in your
2103 board's config file:
2105 #define CONFIG_EXTRA_ENV_SETTINGS \
2109 Warning: This method is based on knowledge about the
2110 internal format how the environment is stored by the
2111 U-Boot code. This is NOT an official, exported
2112 interface! Although it is unlikely that this format
2113 will change soon, there is no guarantee either.
2114 You better know what you are doing here.
2116 Note: overly (ab)use of the default environment is
2117 discouraged. Make sure to check other ways to preset
2118 the environment like the "source" command or the
2121 - DataFlash Support:
2122 CONFIG_HAS_DATAFLASH
2124 Defining this option enables DataFlash features and
2125 allows to read/write in Dataflash via the standard
2128 - SystemACE Support:
2131 Adding this option adds support for Xilinx SystemACE
2132 chips attached via some sort of local bus. The address
2133 of the chip must also be defined in the
2134 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2136 #define CONFIG_SYSTEMACE
2137 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2139 When SystemACE support is added, the "ace" device type
2140 becomes available to the fat commands, i.e. fatls.
2142 - TFTP Fixed UDP Port:
2145 If this is defined, the environment variable tftpsrcp
2146 is used to supply the TFTP UDP source port value.
2147 If tftpsrcp isn't defined, the normal pseudo-random port
2148 number generator is used.
2150 Also, the environment variable tftpdstp is used to supply
2151 the TFTP UDP destination port value. If tftpdstp isn't
2152 defined, the normal port 69 is used.
2154 The purpose for tftpsrcp is to allow a TFTP server to
2155 blindly start the TFTP transfer using the pre-configured
2156 target IP address and UDP port. This has the effect of
2157 "punching through" the (Windows XP) firewall, allowing
2158 the remainder of the TFTP transfer to proceed normally.
2159 A better solution is to properly configure the firewall,
2160 but sometimes that is not allowed.
2162 - Show boot progress:
2163 CONFIG_SHOW_BOOT_PROGRESS
2165 Defining this option allows to add some board-
2166 specific code (calling a user-provided function
2167 "show_boot_progress(int)") that enables you to show
2168 the system's boot progress on some display (for
2169 example, some LED's) on your board. At the moment,
2170 the following checkpoints are implemented:
2172 Legacy uImage format:
2175 1 common/cmd_bootm.c before attempting to boot an image
2176 -1 common/cmd_bootm.c Image header has bad magic number
2177 2 common/cmd_bootm.c Image header has correct magic number
2178 -2 common/cmd_bootm.c Image header has bad checksum
2179 3 common/cmd_bootm.c Image header has correct checksum
2180 -3 common/cmd_bootm.c Image data has bad checksum
2181 4 common/cmd_bootm.c Image data has correct checksum
2182 -4 common/cmd_bootm.c Image is for unsupported architecture
2183 5 common/cmd_bootm.c Architecture check OK
2184 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2185 6 common/cmd_bootm.c Image Type check OK
2186 -6 common/cmd_bootm.c gunzip uncompression error
2187 -7 common/cmd_bootm.c Unimplemented compression type
2188 7 common/cmd_bootm.c Uncompression OK
2189 8 common/cmd_bootm.c No uncompress/copy overwrite error
2190 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2192 9 common/image.c Start initial ramdisk verification
2193 -10 common/image.c Ramdisk header has bad magic number
2194 -11 common/image.c Ramdisk header has bad checksum
2195 10 common/image.c Ramdisk header is OK
2196 -12 common/image.c Ramdisk data has bad checksum
2197 11 common/image.c Ramdisk data has correct checksum
2198 12 common/image.c Ramdisk verification complete, start loading
2199 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2200 13 common/image.c Start multifile image verification
2201 14 common/image.c No initial ramdisk, no multifile, continue.
2203 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2205 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2206 -31 post/post.c POST test failed, detected by post_output_backlog()
2207 -32 post/post.c POST test failed, detected by post_run_single()
2209 34 common/cmd_doc.c before loading a Image from a DOC device
2210 -35 common/cmd_doc.c Bad usage of "doc" command
2211 35 common/cmd_doc.c correct usage of "doc" command
2212 -36 common/cmd_doc.c No boot device
2213 36 common/cmd_doc.c correct boot device
2214 -37 common/cmd_doc.c Unknown Chip ID on boot device
2215 37 common/cmd_doc.c correct chip ID found, device available
2216 -38 common/cmd_doc.c Read Error on boot device
2217 38 common/cmd_doc.c reading Image header from DOC device OK
2218 -39 common/cmd_doc.c Image header has bad magic number
2219 39 common/cmd_doc.c Image header has correct magic number
2220 -40 common/cmd_doc.c Error reading Image from DOC device
2221 40 common/cmd_doc.c Image header has correct magic number
2222 41 common/cmd_ide.c before loading a Image from a IDE device
2223 -42 common/cmd_ide.c Bad usage of "ide" command
2224 42 common/cmd_ide.c correct usage of "ide" command
2225 -43 common/cmd_ide.c No boot device
2226 43 common/cmd_ide.c boot device found
2227 -44 common/cmd_ide.c Device not available
2228 44 common/cmd_ide.c Device available
2229 -45 common/cmd_ide.c wrong partition selected
2230 45 common/cmd_ide.c partition selected
2231 -46 common/cmd_ide.c Unknown partition table
2232 46 common/cmd_ide.c valid partition table found
2233 -47 common/cmd_ide.c Invalid partition type
2234 47 common/cmd_ide.c correct partition type
2235 -48 common/cmd_ide.c Error reading Image Header on boot device
2236 48 common/cmd_ide.c reading Image Header from IDE device OK
2237 -49 common/cmd_ide.c Image header has bad magic number
2238 49 common/cmd_ide.c Image header has correct magic number
2239 -50 common/cmd_ide.c Image header has bad checksum
2240 50 common/cmd_ide.c Image header has correct checksum
2241 -51 common/cmd_ide.c Error reading Image from IDE device
2242 51 common/cmd_ide.c reading Image from IDE device OK
2243 52 common/cmd_nand.c before loading a Image from a NAND device
2244 -53 common/cmd_nand.c Bad usage of "nand" command
2245 53 common/cmd_nand.c correct usage of "nand" command
2246 -54 common/cmd_nand.c No boot device
2247 54 common/cmd_nand.c boot device found
2248 -55 common/cmd_nand.c Unknown Chip ID on boot device
2249 55 common/cmd_nand.c correct chip ID found, device available
2250 -56 common/cmd_nand.c Error reading Image Header on boot device
2251 56 common/cmd_nand.c reading Image Header from NAND device OK
2252 -57 common/cmd_nand.c Image header has bad magic number
2253 57 common/cmd_nand.c Image header has correct magic number
2254 -58 common/cmd_nand.c Error reading Image from NAND device
2255 58 common/cmd_nand.c reading Image from NAND device OK
2257 -60 common/env_common.c Environment has a bad CRC, using default
2259 64 net/eth.c starting with Ethernet configuration.
2260 -64 net/eth.c no Ethernet found.
2261 65 net/eth.c Ethernet found.
2263 -80 common/cmd_net.c usage wrong
2264 80 common/cmd_net.c before calling NetLoop()
2265 -81 common/cmd_net.c some error in NetLoop() occurred
2266 81 common/cmd_net.c NetLoop() back without error
2267 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2268 82 common/cmd_net.c trying automatic boot
2269 83 common/cmd_net.c running "source" command
2270 -83 common/cmd_net.c some error in automatic boot or "source" command
2271 84 common/cmd_net.c end without errors
2276 100 common/cmd_bootm.c Kernel FIT Image has correct format
2277 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2278 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2279 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2280 102 common/cmd_bootm.c Kernel unit name specified
2281 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2282 103 common/cmd_bootm.c Found configuration node
2283 104 common/cmd_bootm.c Got kernel subimage node offset
2284 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2285 105 common/cmd_bootm.c Kernel subimage hash verification OK
2286 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2287 106 common/cmd_bootm.c Architecture check OK
2288 -106 common/cmd_bootm.c Kernel subimage has wrong type
2289 107 common/cmd_bootm.c Kernel subimage type OK
2290 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2291 108 common/cmd_bootm.c Got kernel subimage data/size
2292 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2293 -109 common/cmd_bootm.c Can't get kernel subimage type
2294 -110 common/cmd_bootm.c Can't get kernel subimage comp
2295 -111 common/cmd_bootm.c Can't get kernel subimage os
2296 -112 common/cmd_bootm.c Can't get kernel subimage load address
2297 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2299 120 common/image.c Start initial ramdisk verification
2300 -120 common/image.c Ramdisk FIT image has incorrect format
2301 121 common/image.c Ramdisk FIT image has correct format
2302 122 common/image.c No ramdisk subimage unit name, using configuration
2303 -122 common/image.c Can't get configuration for ramdisk subimage
2304 123 common/image.c Ramdisk unit name specified
2305 -124 common/image.c Can't get ramdisk subimage node offset
2306 125 common/image.c Got ramdisk subimage node offset
2307 -125 common/image.c Ramdisk subimage hash verification failed
2308 126 common/image.c Ramdisk subimage hash verification OK
2309 -126 common/image.c Ramdisk subimage for unsupported architecture
2310 127 common/image.c Architecture check OK
2311 -127 common/image.c Can't get ramdisk subimage data/size
2312 128 common/image.c Got ramdisk subimage data/size
2313 129 common/image.c Can't get ramdisk load address
2314 -129 common/image.c Got ramdisk load address
2316 -130 common/cmd_doc.c Incorrect FIT image format
2317 131 common/cmd_doc.c FIT image format OK
2319 -140 common/cmd_ide.c Incorrect FIT image format
2320 141 common/cmd_ide.c FIT image format OK
2322 -150 common/cmd_nand.c Incorrect FIT image format
2323 151 common/cmd_nand.c FIT image format OK
2325 - Standalone program support:
2326 CONFIG_STANDALONE_LOAD_ADDR
2328 This option defines a board specific value for the
2329 address where standalone program gets loaded, thus
2330 overwriting the architecture dependent default
2333 - Frame Buffer Address:
2336 Define CONFIG_FB_ADDR if you want to use specific
2337 address for frame buffer.
2338 Then system will reserve the frame buffer address to
2339 defined address instead of lcd_setmem (this function
2340 grabs the memory for frame buffer by panel's size).
2342 Please see board_init_f function.
2344 - Automatic software updates via TFTP server
2346 CONFIG_UPDATE_TFTP_CNT_MAX
2347 CONFIG_UPDATE_TFTP_MSEC_MAX
2349 These options enable and control the auto-update feature;
2350 for a more detailed description refer to doc/README.update.
2352 - MTD Support (mtdparts command, UBI support)
2355 Adds the MTD device infrastructure from the Linux kernel.
2356 Needed for mtdparts command support.
2358 CONFIG_MTD_PARTITIONS
2360 Adds the MTD partitioning infrastructure from the Linux
2361 kernel. Needed for UBI support.
2365 Enable building of SPL globally.
2367 CONFIG_SPL_TEXT_BASE
2368 TEXT_BASE for linking the SPL binary.
2371 LDSCRIPT for linking the SPL binary.
2373 CONFIG_SPL_LIBCOMMON_SUPPORT
2374 Support for common/libcommon.o in SPL binary
2376 CONFIG_SPL_LIBDISK_SUPPORT
2377 Support for disk/libdisk.o in SPL binary
2379 CONFIG_SPL_I2C_SUPPORT
2380 Support for drivers/i2c/libi2c.o in SPL binary
2382 CONFIG_SPL_GPIO_SUPPORT
2383 Support for drivers/gpio/libgpio.o in SPL binary
2385 CONFIG_SPL_MMC_SUPPORT
2386 Support for drivers/mmc/libmmc.o in SPL binary
2388 CONFIG_SPL_SERIAL_SUPPORT
2389 Support for drivers/serial/libserial.o in SPL binary
2391 CONFIG_SPL_SPI_FLASH_SUPPORT
2392 Support for drivers/mtd/spi/libspi_flash.o in SPL binary
2394 CONFIG_SPL_SPI_SUPPORT
2395 Support for drivers/spi/libspi.o in SPL binary
2397 CONFIG_SPL_FAT_SUPPORT
2398 Support for fs/fat/libfat.o in SPL binary
2400 CONFIG_SPL_LIBGENERIC_SUPPORT
2401 Support for lib/libgeneric.o in SPL binary
2406 [so far only for SMDK2400 boards]
2408 - Modem support enable:
2409 CONFIG_MODEM_SUPPORT
2411 - RTS/CTS Flow control enable:
2414 - Modem debug support:
2415 CONFIG_MODEM_SUPPORT_DEBUG
2417 Enables debugging stuff (char screen[1024], dbg())
2418 for modem support. Useful only with BDI2000.
2420 - Interrupt support (PPC):
2422 There are common interrupt_init() and timer_interrupt()
2423 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2424 for CPU specific initialization. interrupt_init_cpu()
2425 should set decrementer_count to appropriate value. If
2426 CPU resets decrementer automatically after interrupt
2427 (ppc4xx) it should set decrementer_count to zero.
2428 timer_interrupt() calls timer_interrupt_cpu() for CPU
2429 specific handling. If board has watchdog / status_led
2430 / other_activity_monitor it works automatically from
2431 general timer_interrupt().
2435 In the target system modem support is enabled when a
2436 specific key (key combination) is pressed during
2437 power-on. Otherwise U-Boot will boot normally
2438 (autoboot). The key_pressed() function is called from
2439 board_init(). Currently key_pressed() is a dummy
2440 function, returning 1 and thus enabling modem
2443 If there are no modem init strings in the
2444 environment, U-Boot proceed to autoboot; the
2445 previous output (banner, info printfs) will be
2448 See also: doc/README.Modem
2451 Configuration Settings:
2452 -----------------------
2454 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2455 undefine this when you're short of memory.
2457 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2458 width of the commands listed in the 'help' command output.
2460 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2461 prompt for user input.
2463 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2465 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2467 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2469 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2470 the application (usually a Linux kernel) when it is
2473 - CONFIG_SYS_BAUDRATE_TABLE:
2474 List of legal baudrate settings for this board.
2476 - CONFIG_SYS_CONSOLE_INFO_QUIET
2477 Suppress display of console information at boot.
2479 - CONFIG_SYS_CONSOLE_IS_IN_ENV
2480 If the board specific function
2481 extern int overwrite_console (void);
2482 returns 1, the stdin, stderr and stdout are switched to the
2483 serial port, else the settings in the environment are used.
2485 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
2486 Enable the call to overwrite_console().
2488 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
2489 Enable overwrite of previous console environment settings.
2491 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2492 Begin and End addresses of the area used by the
2495 - CONFIG_SYS_ALT_MEMTEST:
2496 Enable an alternate, more extensive memory test.
2498 - CONFIG_SYS_MEMTEST_SCRATCH:
2499 Scratch address used by the alternate memory test
2500 You only need to set this if address zero isn't writeable
2502 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
2503 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2504 this specified memory area will get subtracted from the top
2505 (end) of RAM and won't get "touched" at all by U-Boot. By
2506 fixing up gd->ram_size the Linux kernel should gets passed
2507 the now "corrected" memory size and won't touch it either.
2508 This should work for arch/ppc and arch/powerpc. Only Linux
2509 board ports in arch/powerpc with bootwrapper support that
2510 recalculate the memory size from the SDRAM controller setup
2511 will have to get fixed in Linux additionally.
2513 This option can be used as a workaround for the 440EPx/GRx
2514 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2517 WARNING: Please make sure that this value is a multiple of
2518 the Linux page size (normally 4k). If this is not the case,
2519 then the end address of the Linux memory will be located at a
2520 non page size aligned address and this could cause major
2523 - CONFIG_SYS_TFTP_LOADADDR:
2524 Default load address for network file downloads
2526 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2527 Enable temporary baudrate change while serial download
2529 - CONFIG_SYS_SDRAM_BASE:
2530 Physical start address of SDRAM. _Must_ be 0 here.
2532 - CONFIG_SYS_MBIO_BASE:
2533 Physical start address of Motherboard I/O (if using a
2536 - CONFIG_SYS_FLASH_BASE:
2537 Physical start address of Flash memory.
2539 - CONFIG_SYS_MONITOR_BASE:
2540 Physical start address of boot monitor code (set by
2541 make config files to be same as the text base address
2542 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2543 CONFIG_SYS_FLASH_BASE when booting from flash.
2545 - CONFIG_SYS_MONITOR_LEN:
2546 Size of memory reserved for monitor code, used to
2547 determine _at_compile_time_ (!) if the environment is
2548 embedded within the U-Boot image, or in a separate
2551 - CONFIG_SYS_MALLOC_LEN:
2552 Size of DRAM reserved for malloc() use.
2554 - CONFIG_SYS_BOOTM_LEN:
2555 Normally compressed uImages are limited to an
2556 uncompressed size of 8 MBytes. If this is not enough,
2557 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2558 to adjust this setting to your needs.
2560 - CONFIG_SYS_BOOTMAPSZ:
2561 Maximum size of memory mapped by the startup code of
2562 the Linux kernel; all data that must be processed by
2563 the Linux kernel (bd_info, boot arguments, FDT blob if
2564 used) must be put below this limit, unless "bootm_low"
2565 enviroment variable is defined and non-zero. In such case
2566 all data for the Linux kernel must be between "bootm_low"
2567 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2568 variable "bootm_mapsize" will override the value of
2569 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2570 then the value in "bootm_size" will be used instead.
2572 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2573 Enable initrd_high functionality. If defined then the
2574 initrd_high feature is enabled and the bootm ramdisk subcommand
2577 - CONFIG_SYS_BOOT_GET_CMDLINE:
2578 Enables allocating and saving kernel cmdline in space between
2579 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2581 - CONFIG_SYS_BOOT_GET_KBD:
2582 Enables allocating and saving a kernel copy of the bd_info in
2583 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2585 - CONFIG_SYS_MAX_FLASH_BANKS:
2586 Max number of Flash memory banks
2588 - CONFIG_SYS_MAX_FLASH_SECT:
2589 Max number of sectors on a Flash chip
2591 - CONFIG_SYS_FLASH_ERASE_TOUT:
2592 Timeout for Flash erase operations (in ms)
2594 - CONFIG_SYS_FLASH_WRITE_TOUT:
2595 Timeout for Flash write operations (in ms)
2597 - CONFIG_SYS_FLASH_LOCK_TOUT
2598 Timeout for Flash set sector lock bit operation (in ms)
2600 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2601 Timeout for Flash clear lock bits operation (in ms)
2603 - CONFIG_SYS_FLASH_PROTECTION
2604 If defined, hardware flash sectors protection is used
2605 instead of U-Boot software protection.
2607 - CONFIG_SYS_DIRECT_FLASH_TFTP:
2609 Enable TFTP transfers directly to flash memory;
2610 without this option such a download has to be
2611 performed in two steps: (1) download to RAM, and (2)
2612 copy from RAM to flash.
2614 The two-step approach is usually more reliable, since
2615 you can check if the download worked before you erase
2616 the flash, but in some situations (when system RAM is
2617 too limited to allow for a temporary copy of the
2618 downloaded image) this option may be very useful.
2620 - CONFIG_SYS_FLASH_CFI:
2621 Define if the flash driver uses extra elements in the
2622 common flash structure for storing flash geometry.
2624 - CONFIG_FLASH_CFI_DRIVER
2625 This option also enables the building of the cfi_flash driver
2626 in the drivers directory
2628 - CONFIG_FLASH_CFI_MTD
2629 This option enables the building of the cfi_mtd driver
2630 in the drivers directory. The driver exports CFI flash
2633 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
2634 Use buffered writes to flash.
2636 - CONFIG_FLASH_SPANSION_S29WS_N
2637 s29ws-n MirrorBit flash has non-standard addresses for buffered
2640 - CONFIG_SYS_FLASH_QUIET_TEST
2641 If this option is defined, the common CFI flash doesn't
2642 print it's warning upon not recognized FLASH banks. This
2643 is useful, if some of the configured banks are only
2644 optionally available.
2646 - CONFIG_FLASH_SHOW_PROGRESS
2647 If defined (must be an integer), print out countdown
2648 digits and dots. Recommended value: 45 (9..1) for 80
2649 column displays, 15 (3..1) for 40 column displays.
2651 - CONFIG_SYS_RX_ETH_BUFFER:
2652 Defines the number of Ethernet receive buffers. On some
2653 Ethernet controllers it is recommended to set this value
2654 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2655 buffers can be full shortly after enabling the interface
2656 on high Ethernet traffic.
2657 Defaults to 4 if not defined.
2659 - CONFIG_ENV_MAX_ENTRIES
2661 Maximum number of entries in the hash table that is used
2662 internally to store the environment settings. The default
2663 setting is supposed to be generous and should work in most
2664 cases. This setting can be used to tune behaviour; see
2665 lib/hashtable.c for details.
2667 The following definitions that deal with the placement and management
2668 of environment data (variable area); in general, we support the
2669 following configurations:
2671 - CONFIG_BUILD_ENVCRC:
2673 Builds up envcrc with the target environment so that external utils
2674 may easily extract it and embed it in final U-Boot images.
2676 - CONFIG_ENV_IS_IN_FLASH:
2678 Define this if the environment is in flash memory.
2680 a) The environment occupies one whole flash sector, which is
2681 "embedded" in the text segment with the U-Boot code. This
2682 happens usually with "bottom boot sector" or "top boot
2683 sector" type flash chips, which have several smaller
2684 sectors at the start or the end. For instance, such a
2685 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2686 such a case you would place the environment in one of the
2687 4 kB sectors - with U-Boot code before and after it. With
2688 "top boot sector" type flash chips, you would put the
2689 environment in one of the last sectors, leaving a gap
2690 between U-Boot and the environment.
2692 - CONFIG_ENV_OFFSET:
2694 Offset of environment data (variable area) to the
2695 beginning of flash memory; for instance, with bottom boot
2696 type flash chips the second sector can be used: the offset
2697 for this sector is given here.
2699 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
2703 This is just another way to specify the start address of
2704 the flash sector containing the environment (instead of
2707 - CONFIG_ENV_SECT_SIZE:
2709 Size of the sector containing the environment.
2712 b) Sometimes flash chips have few, equal sized, BIG sectors.
2713 In such a case you don't want to spend a whole sector for
2718 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
2719 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
2720 of this flash sector for the environment. This saves
2721 memory for the RAM copy of the environment.
2723 It may also save flash memory if you decide to use this
2724 when your environment is "embedded" within U-Boot code,
2725 since then the remainder of the flash sector could be used
2726 for U-Boot code. It should be pointed out that this is
2727 STRONGLY DISCOURAGED from a robustness point of view:
2728 updating the environment in flash makes it always
2729 necessary to erase the WHOLE sector. If something goes
2730 wrong before the contents has been restored from a copy in
2731 RAM, your target system will be dead.
2733 - CONFIG_ENV_ADDR_REDUND
2734 CONFIG_ENV_SIZE_REDUND
2736 These settings describe a second storage area used to hold
2737 a redundant copy of the environment data, so that there is
2738 a valid backup copy in case there is a power failure during
2739 a "saveenv" operation.
2741 BE CAREFUL! Any changes to the flash layout, and some changes to the
2742 source code will make it necessary to adapt <board>/u-boot.lds*
2746 - CONFIG_ENV_IS_IN_NVRAM:
2748 Define this if you have some non-volatile memory device
2749 (NVRAM, battery buffered SRAM) which you want to use for the
2755 These two #defines are used to determine the memory area you
2756 want to use for environment. It is assumed that this memory
2757 can just be read and written to, without any special
2760 BE CAREFUL! The first access to the environment happens quite early
2761 in U-Boot initalization (when we try to get the setting of for the
2762 console baudrate). You *MUST* have mapped your NVRAM area then, or
2765 Please note that even with NVRAM we still use a copy of the
2766 environment in RAM: we could work on NVRAM directly, but we want to
2767 keep settings there always unmodified except somebody uses "saveenv"
2768 to save the current settings.
2771 - CONFIG_ENV_IS_IN_EEPROM:
2773 Use this if you have an EEPROM or similar serial access
2774 device and a driver for it.
2776 - CONFIG_ENV_OFFSET:
2779 These two #defines specify the offset and size of the
2780 environment area within the total memory of your EEPROM.
2782 - CONFIG_SYS_I2C_EEPROM_ADDR:
2783 If defined, specified the chip address of the EEPROM device.
2784 The default address is zero.
2786 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
2787 If defined, the number of bits used to address bytes in a
2788 single page in the EEPROM device. A 64 byte page, for example
2789 would require six bits.
2791 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
2792 If defined, the number of milliseconds to delay between
2793 page writes. The default is zero milliseconds.
2795 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
2796 The length in bytes of the EEPROM memory array address. Note
2797 that this is NOT the chip address length!
2799 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
2800 EEPROM chips that implement "address overflow" are ones
2801 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2802 address and the extra bits end up in the "chip address" bit
2803 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2806 Note that we consider the length of the address field to
2807 still be one byte because the extra address bits are hidden
2808 in the chip address.
2810 - CONFIG_SYS_EEPROM_SIZE:
2811 The size in bytes of the EEPROM device.
2813 - CONFIG_ENV_EEPROM_IS_ON_I2C
2814 define this, if you have I2C and SPI activated, and your
2815 EEPROM, which holds the environment, is on the I2C bus.
2817 - CONFIG_I2C_ENV_EEPROM_BUS
2818 if you have an Environment on an EEPROM reached over
2819 I2C muxes, you can define here, how to reach this
2820 EEPROM. For example:
2822 #define CONFIG_I2C_ENV_EEPROM_BUS "pca9547:70:d\0"
2824 EEPROM which holds the environment, is reached over
2825 a pca9547 i2c mux with address 0x70, channel 3.
2827 - CONFIG_ENV_IS_IN_DATAFLASH:
2829 Define this if you have a DataFlash memory device which you
2830 want to use for the environment.
2832 - CONFIG_ENV_OFFSET:
2836 These three #defines specify the offset and size of the
2837 environment area within the total memory of your DataFlash placed
2838 at the specified address.
2840 - CONFIG_ENV_IS_IN_NAND:
2842 Define this if you have a NAND device which you want to use
2843 for the environment.
2845 - CONFIG_ENV_OFFSET:
2848 These two #defines specify the offset and size of the environment
2849 area within the first NAND device. CONFIG_ENV_OFFSET must be
2850 aligned to an erase block boundary.
2852 - CONFIG_ENV_OFFSET_REDUND (optional):
2854 This setting describes a second storage area of CONFIG_ENV_SIZE
2855 size used to hold a redundant copy of the environment data, so
2856 that there is a valid backup copy in case there is a power failure
2857 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
2858 aligned to an erase block boundary.
2860 - CONFIG_ENV_RANGE (optional):
2862 Specifies the length of the region in which the environment
2863 can be written. This should be a multiple of the NAND device's
2864 block size. Specifying a range with more erase blocks than
2865 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
2866 the range to be avoided.
2868 - CONFIG_ENV_OFFSET_OOB (optional):
2870 Enables support for dynamically retrieving the offset of the
2871 environment from block zero's out-of-band data. The
2872 "nand env.oob" command can be used to record this offset.
2873 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
2874 using CONFIG_ENV_OFFSET_OOB.
2876 - CONFIG_NAND_ENV_DST
2878 Defines address in RAM to which the nand_spl code should copy the
2879 environment. If redundant environment is used, it will be copied to
2880 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
2882 - CONFIG_SYS_SPI_INIT_OFFSET
2884 Defines offset to the initial SPI buffer area in DPRAM. The
2885 area is used at an early stage (ROM part) if the environment
2886 is configured to reside in the SPI EEPROM: We need a 520 byte
2887 scratch DPRAM area. It is used between the two initialization
2888 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2889 to be a good choice since it makes it far enough from the
2890 start of the data area as well as from the stack pointer.
2892 Please note that the environment is read-only until the monitor
2893 has been relocated to RAM and a RAM copy of the environment has been
2894 created; also, when using EEPROM you will have to use getenv_f()
2895 until then to read environment variables.
2897 The environment is protected by a CRC32 checksum. Before the monitor
2898 is relocated into RAM, as a result of a bad CRC you will be working
2899 with the compiled-in default environment - *silently*!!! [This is
2900 necessary, because the first environment variable we need is the
2901 "baudrate" setting for the console - if we have a bad CRC, we don't
2902 have any device yet where we could complain.]
2904 Note: once the monitor has been relocated, then it will complain if
2905 the default environment is used; a new CRC is computed as soon as you
2906 use the "saveenv" command to store a valid environment.
2908 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
2909 Echo the inverted Ethernet link state to the fault LED.
2911 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
2912 also needs to be defined.
2914 - CONFIG_SYS_FAULT_MII_ADDR:
2915 MII address of the PHY to check for the Ethernet link state.
2917 - CONFIG_NS16550_MIN_FUNCTIONS:
2918 Define this if you desire to only have use of the NS16550_init
2919 and NS16550_putc functions for the serial driver located at
2920 drivers/serial/ns16550.c. This option is useful for saving
2921 space for already greatly restricted images, including but not
2922 limited to NAND_SPL configurations.
2924 Low Level (hardware related) configuration options:
2925 ---------------------------------------------------
2927 - CONFIG_SYS_CACHELINE_SIZE:
2928 Cache Line Size of the CPU.
2930 - CONFIG_SYS_DEFAULT_IMMR:
2931 Default address of the IMMR after system reset.
2933 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2934 and RPXsuper) to be able to adjust the position of
2935 the IMMR register after a reset.
2937 - CONFIG_SYS_CCSRBAR_DEFAULT:
2938 Default (power-on reset) physical address of CCSR on Freescale
2941 - CONFIG_SYS_CCSRBAR:
2942 Virtual address of CCSR. On a 32-bit build, this is typically
2943 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
2945 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
2946 for cross-platform code that uses that macro instead.
2948 - CONFIG_SYS_CCSRBAR_PHYS:
2949 Physical address of CCSR. CCSR can be relocated to a new
2950 physical address, if desired. In this case, this macro should
2951 be set to that address. Otherwise, it should be set to the
2952 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
2953 is typically relocated on 36-bit builds. It is recommended
2954 that this macro be defined via the _HIGH and _LOW macros:
2956 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
2957 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
2959 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
2960 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
2961 either 0 (32-bit build) or 0xF (36-bit build). This macro is
2962 used in assembly code, so it must not contain typecasts or
2963 integer size suffixes (e.g. "ULL").
2965 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
2966 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
2967 used in assembly code, so it must not contain typecasts or
2968 integer size suffixes (e.g. "ULL").
2970 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
2971 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
2972 forced to a value that ensures that CCSR is not relocated.
2974 - Floppy Disk Support:
2975 CONFIG_SYS_FDC_DRIVE_NUMBER
2977 the default drive number (default value 0)
2979 CONFIG_SYS_ISA_IO_STRIDE
2981 defines the spacing between FDC chipset registers
2984 CONFIG_SYS_ISA_IO_OFFSET
2986 defines the offset of register from address. It
2987 depends on which part of the data bus is connected to
2988 the FDC chipset. (default value 0)
2990 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
2991 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
2994 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
2995 fdc_hw_init() is called at the beginning of the FDC
2996 setup. fdc_hw_init() must be provided by the board
2997 source code. It is used to make hardware dependant
3001 Most IDE controllers were designed to be connected with PCI
3002 interface. Only few of them were designed for AHB interface.
3003 When software is doing ATA command and data transfer to
3004 IDE devices through IDE-AHB controller, some additional
3005 registers accessing to these kind of IDE-AHB controller
3008 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3009 DO NOT CHANGE unless you know exactly what you're
3010 doing! (11-4) [MPC8xx/82xx systems only]
3012 - CONFIG_SYS_INIT_RAM_ADDR:
3014 Start address of memory area that can be used for
3015 initial data and stack; please note that this must be
3016 writable memory that is working WITHOUT special
3017 initialization, i. e. you CANNOT use normal RAM which
3018 will become available only after programming the
3019 memory controller and running certain initialization
3022 U-Boot uses the following memory types:
3023 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
3024 - MPC824X: data cache
3025 - PPC4xx: data cache
3027 - CONFIG_SYS_GBL_DATA_OFFSET:
3029 Offset of the initial data structure in the memory
3030 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3031 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3032 data is located at the end of the available space
3033 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3034 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
3035 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3036 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3039 On the MPC824X (or other systems that use the data
3040 cache for initial memory) the address chosen for
3041 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3042 point to an otherwise UNUSED address space between
3043 the top of RAM and the start of the PCI space.
3045 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
3047 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
3049 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
3051 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
3053 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
3055 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3057 - CONFIG_SYS_OR_TIMING_SDRAM:
3060 - CONFIG_SYS_MAMR_PTA:
3061 periodic timer for refresh
3063 - CONFIG_SYS_DER: Debug Event Register (37-47)
3065 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3066 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3067 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3068 CONFIG_SYS_BR1_PRELIM:
3069 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3071 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3072 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3073 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3074 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3076 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
3077 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
3078 Machine Mode Register and Memory Periodic Timer
3079 Prescaler definitions (SDRAM timing)
3081 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
3082 enable I2C microcode relocation patch (MPC8xx);
3083 define relocation offset in DPRAM [DSP2]
3085 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
3086 enable SMC microcode relocation patch (MPC8xx);
3087 define relocation offset in DPRAM [SMC1]
3089 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
3090 enable SPI microcode relocation patch (MPC8xx);
3091 define relocation offset in DPRAM [SCC4]
3093 - CONFIG_SYS_USE_OSCCLK:
3094 Use OSCM clock mode on MBX8xx board. Be careful,
3095 wrong setting might damage your board. Read
3096 doc/README.MBX before setting this variable!
3098 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
3099 Offset of the bootmode word in DPRAM used by post
3100 (Power On Self Tests). This definition overrides
3101 #define'd default value in commproc.h resp.
3104 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
3105 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
3106 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
3107 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
3108 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
3109 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
3110 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
3111 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
3112 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
3114 - CONFIG_PCI_DISABLE_PCIE:
3115 Disable PCI-Express on systems where it is supported but not
3119 Chip has SRIO or not
3122 Board has SRIO 1 port available
3125 Board has SRIO 2 port available
3127 - CONFIG_SYS_SRIOn_MEM_VIRT:
3128 Virtual Address of SRIO port 'n' memory region
3130 - CONFIG_SYS_SRIOn_MEM_PHYS:
3131 Physical Address of SRIO port 'n' memory region
3133 - CONFIG_SYS_SRIOn_MEM_SIZE:
3134 Size of SRIO port 'n' memory region
3136 - CONFIG_SYS_NDFC_16
3137 Defined to tell the NDFC that the NAND chip is using a
3140 - CONFIG_SYS_NDFC_EBC0_CFG
3141 Sets the EBC0_CFG register for the NDFC. If not defined
3142 a default value will be used.
3145 Get DDR timing information from an I2C EEPROM. Common
3146 with pluggable memory modules such as SODIMMs
3149 I2C address of the SPD EEPROM
3151 - CONFIG_SYS_SPD_BUS_NUM
3152 If SPD EEPROM is on an I2C bus other than the first
3153 one, specify here. Note that the value must resolve
3154 to something your driver can deal with.
3156 - CONFIG_SYS_DDR_RAW_TIMING
3157 Get DDR timing information from other than SPD. Common with
3158 soldered DDR chips onboard without SPD. DDR raw timing
3159 parameters are extracted from datasheet and hard-coded into
3160 header files or board specific files.
3162 - CONFIG_FSL_DDR_INTERACTIVE
3163 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3165 - CONFIG_SYS_83XX_DDR_USES_CS0
3166 Only for 83xx systems. If specified, then DDR should
3167 be configured using CS0 and CS1 instead of CS2 and CS3.
3169 - CONFIG_ETHER_ON_FEC[12]
3170 Define to enable FEC[12] on a 8xx series processor.
3172 - CONFIG_FEC[12]_PHY
3173 Define to the hardcoded PHY address which corresponds
3174 to the given FEC; i. e.
3175 #define CONFIG_FEC1_PHY 4
3176 means that the PHY with address 4 is connected to FEC1
3178 When set to -1, means to probe for first available.
3180 - CONFIG_FEC[12]_PHY_NORXERR
3181 The PHY does not have a RXERR line (RMII only).
3182 (so program the FEC to ignore it).
3185 Enable RMII mode for all FECs.
3186 Note that this is a global option, we can't
3187 have one FEC in standard MII mode and another in RMII mode.
3189 - CONFIG_CRC32_VERIFY
3190 Add a verify option to the crc32 command.
3193 => crc32 -v <address> <count> <crc32>
3195 Where address/count indicate a memory area
3196 and crc32 is the correct crc32 which the
3200 Add the "loopw" memory command. This only takes effect if
3201 the memory commands are activated globally (CONFIG_CMD_MEM).
3204 Add the "mdc" and "mwc" memory commands. These are cyclic
3209 This command will print 4 bytes (10,11,12,13) each 500 ms.
3211 => mwc.l 100 12345678 10
3212 This command will write 12345678 to address 100 all 10 ms.
3214 This only takes effect if the memory commands are activated
3215 globally (CONFIG_CMD_MEM).
3217 - CONFIG_SKIP_LOWLEVEL_INIT
3218 [ARM, NDS32, MIPS only] If this variable is defined, then certain
3219 low level initializations (like setting up the memory
3220 controller) are omitted and/or U-Boot does not
3221 relocate itself into RAM.
3223 Normally this variable MUST NOT be defined. The only
3224 exception is when U-Boot is loaded (to RAM) by some
3225 other boot loader or by a debugger which performs
3226 these initializations itself.
3229 Modifies the behaviour of start.S when compiling a loader
3230 that is executed before the actual U-Boot. E.g. when
3231 compiling a NAND SPL.
3233 - CONFIG_USE_ARCH_MEMCPY
3234 CONFIG_USE_ARCH_MEMSET
3235 If these options are used a optimized version of memcpy/memset will
3236 be used if available. These functions may be faster under some
3237 conditions but may increase the binary size.
3239 Building the Software:
3240 ======================
3242 Building U-Boot has been tested in several native build environments
3243 and in many different cross environments. Of course we cannot support
3244 all possibly existing versions of cross development tools in all
3245 (potentially obsolete) versions. In case of tool chain problems we
3246 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3247 which is extensively used to build and test U-Boot.
3249 If you are not using a native environment, it is assumed that you
3250 have GNU cross compiling tools available in your path. In this case,
3251 you must set the environment variable CROSS_COMPILE in your shell.
3252 Note that no changes to the Makefile or any other source files are
3253 necessary. For example using the ELDK on a 4xx CPU, please enter:
3255 $ CROSS_COMPILE=ppc_4xx-
3256 $ export CROSS_COMPILE
3258 Note: If you wish to generate Windows versions of the utilities in
3259 the tools directory you can use the MinGW toolchain
3260 (http://www.mingw.org). Set your HOST tools to the MinGW
3261 toolchain and execute 'make tools'. For example:
3263 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3265 Binaries such as tools/mkimage.exe will be created which can
3266 be executed on computers running Windows.
3268 U-Boot is intended to be simple to build. After installing the
3269 sources you must configure U-Boot for one specific board type. This
3274 where "NAME_config" is the name of one of the existing configu-
3275 rations; see the main Makefile for supported names.
3277 Note: for some board special configuration names may exist; check if
3278 additional information is available from the board vendor; for
3279 instance, the TQM823L systems are available without (standard)
3280 or with LCD support. You can select such additional "features"
3281 when choosing the configuration, i. e.
3284 - will configure for a plain TQM823L, i. e. no LCD support
3286 make TQM823L_LCD_config
3287 - will configure for a TQM823L with U-Boot console on LCD
3292 Finally, type "make all", and you should get some working U-Boot
3293 images ready for download to / installation on your system:
3295 - "u-boot.bin" is a raw binary image
3296 - "u-boot" is an image in ELF binary format
3297 - "u-boot.srec" is in Motorola S-Record format
3299 By default the build is performed locally and the objects are saved
3300 in the source directory. One of the two methods can be used to change
3301 this behavior and build U-Boot to some external directory:
3303 1. Add O= to the make command line invocations:
3305 make O=/tmp/build distclean
3306 make O=/tmp/build NAME_config
3307 make O=/tmp/build all
3309 2. Set environment variable BUILD_DIR to point to the desired location:
3311 export BUILD_DIR=/tmp/build
3316 Note that the command line "O=" setting overrides the BUILD_DIR environment
3320 Please be aware that the Makefiles assume you are using GNU make, so
3321 for instance on NetBSD you might need to use "gmake" instead of
3325 If the system board that you have is not listed, then you will need
3326 to port U-Boot to your hardware platform. To do this, follow these
3329 1. Add a new configuration option for your board to the toplevel
3330 "Makefile" and to the "MAKEALL" script, using the existing
3331 entries as examples. Note that here and at many other places
3332 boards and other names are listed in alphabetical sort order. Please
3334 2. Create a new directory to hold your board specific code. Add any
3335 files you need. In your board directory, you will need at least
3336 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
3337 3. Create a new configuration file "include/configs/<board>.h" for
3339 3. If you're porting U-Boot to a new CPU, then also create a new
3340 directory to hold your CPU specific code. Add any files you need.
3341 4. Run "make <board>_config" with your new name.
3342 5. Type "make", and you should get a working "u-boot.srec" file
3343 to be installed on your target system.
3344 6. Debug and solve any problems that might arise.
3345 [Of course, this last step is much harder than it sounds.]
3348 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3349 ==============================================================
3351 If you have modified U-Boot sources (for instance added a new board
3352 or support for new devices, a new CPU, etc.) you are expected to
3353 provide feedback to the other developers. The feedback normally takes
3354 the form of a "patch", i. e. a context diff against a certain (latest
3355 official or latest in the git repository) version of U-Boot sources.
3357 But before you submit such a patch, please verify that your modifi-
3358 cation did not break existing code. At least make sure that *ALL* of
3359 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3360 just run the "MAKEALL" script, which will configure and build U-Boot
3361 for ALL supported system. Be warned, this will take a while. You can
3362 select which (cross) compiler to use by passing a `CROSS_COMPILE'
3363 environment variable to the script, i. e. to use the ELDK cross tools
3366 CROSS_COMPILE=ppc_8xx- MAKEALL
3368 or to build on a native PowerPC system you can type
3370 CROSS_COMPILE=' ' MAKEALL
3372 When using the MAKEALL script, the default behaviour is to build
3373 U-Boot in the source directory. This location can be changed by
3374 setting the BUILD_DIR environment variable. Also, for each target
3375 built, the MAKEALL script saves two log files (<target>.ERR and
3376 <target>.MAKEALL) in the <source dir>/LOG directory. This default
3377 location can be changed by setting the MAKEALL_LOGDIR environment
3378 variable. For example:
3380 export BUILD_DIR=/tmp/build
3381 export MAKEALL_LOGDIR=/tmp/log
3382 CROSS_COMPILE=ppc_8xx- MAKEALL
3384 With the above settings build objects are saved in the /tmp/build,
3385 log files are saved in the /tmp/log and the source tree remains clean
3386 during the whole build process.
3389 See also "U-Boot Porting Guide" below.
3392 Monitor Commands - Overview:
3393 ============================
3395 go - start application at address 'addr'
3396 run - run commands in an environment variable
3397 bootm - boot application image from memory
3398 bootp - boot image via network using BootP/TFTP protocol
3399 tftpboot- boot image via network using TFTP protocol
3400 and env variables "ipaddr" and "serverip"
3401 (and eventually "gatewayip")
3402 tftpput - upload a file via network using TFTP protocol
3403 rarpboot- boot image via network using RARP/TFTP protocol
3404 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3405 loads - load S-Record file over serial line
3406 loadb - load binary file over serial line (kermit mode)
3408 mm - memory modify (auto-incrementing)
3409 nm - memory modify (constant address)
3410 mw - memory write (fill)
3412 cmp - memory compare
3413 crc32 - checksum calculation
3414 i2c - I2C sub-system
3415 sspi - SPI utility commands
3416 base - print or set address offset
3417 printenv- print environment variables
3418 setenv - set environment variables
3419 saveenv - save environment variables to persistent storage
3420 protect - enable or disable FLASH write protection
3421 erase - erase FLASH memory
3422 flinfo - print FLASH memory information
3423 bdinfo - print Board Info structure
3424 iminfo - print header information for application image
3425 coninfo - print console devices and informations
3426 ide - IDE sub-system
3427 loop - infinite loop on address range
3428 loopw - infinite write loop on address range
3429 mtest - simple RAM test
3430 icache - enable or disable instruction cache
3431 dcache - enable or disable data cache
3432 reset - Perform RESET of the CPU
3433 echo - echo args to console
3434 version - print monitor version
3435 help - print online help
3436 ? - alias for 'help'
3439 Monitor Commands - Detailed Description:
3440 ========================================
3444 For now: just type "help <command>".
3447 Environment Variables:
3448 ======================
3450 U-Boot supports user configuration using Environment Variables which
3451 can be made persistent by saving to Flash memory.
3453 Environment Variables are set using "setenv", printed using
3454 "printenv", and saved to Flash using "saveenv". Using "setenv"
3455 without a value can be used to delete a variable from the
3456 environment. As long as you don't save the environment you are
3457 working with an in-memory copy. In case the Flash area containing the
3458 environment is erased by accident, a default environment is provided.
3460 Some configuration options can be set using Environment Variables.
3462 List of environment variables (most likely not complete):
3464 baudrate - see CONFIG_BAUDRATE
3466 bootdelay - see CONFIG_BOOTDELAY
3468 bootcmd - see CONFIG_BOOTCOMMAND
3470 bootargs - Boot arguments when booting an RTOS image
3472 bootfile - Name of the image to load with TFTP
3474 bootm_low - Memory range available for image processing in the bootm
3475 command can be restricted. This variable is given as
3476 a hexadecimal number and defines lowest address allowed
3477 for use by the bootm command. See also "bootm_size"
3478 environment variable. Address defined by "bootm_low" is
3479 also the base of the initial memory mapping for the Linux
3480 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3483 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3484 This variable is given as a hexadecimal number and it
3485 defines the size of the memory region starting at base
3486 address bootm_low that is accessible by the Linux kernel
3487 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3488 as the default value if it is defined, and bootm_size is
3491 bootm_size - Memory range available for image processing in the bootm
3492 command can be restricted. This variable is given as
3493 a hexadecimal number and defines the size of the region
3494 allowed for use by the bootm command. See also "bootm_low"
3495 environment variable.
3497 updatefile - Location of the software update file on a TFTP server, used
3498 by the automatic software update feature. Please refer to
3499 documentation in doc/README.update for more details.
3501 autoload - if set to "no" (any string beginning with 'n'),
3502 "bootp" will just load perform a lookup of the
3503 configuration from the BOOTP server, but not try to
3504 load any image using TFTP
3506 autostart - if set to "yes", an image loaded using the "bootp",
3507 "rarpboot", "tftpboot" or "diskboot" commands will
3508 be automatically started (by internally calling
3511 If set to "no", a standalone image passed to the
3512 "bootm" command will be copied to the load address
3513 (and eventually uncompressed), but NOT be started.
3514 This can be used to load and uncompress arbitrary
3517 fdt_high - if set this restricts the maximum address that the
3518 flattened device tree will be copied into upon boot.
3519 If this is set to the special value 0xFFFFFFFF then
3520 the fdt will not be copied at all on boot. For this
3521 to work it must reside in writable memory, have
3522 sufficient padding on the end of it for u-boot to
3523 add the information it needs into it, and the memory
3524 must be accessible by the kernel.
3526 fdtcontroladdr- if set this is the address of the control flattened
3527 device tree used by U-Boot when CONFIG_OF_CONTROL is
3530 i2cfast - (PPC405GP|PPC405EP only)
3531 if set to 'y' configures Linux I2C driver for fast
3532 mode (400kHZ). This environment variable is used in
3533 initialization code. So, for changes to be effective
3534 it must be saved and board must be reset.
3536 initrd_high - restrict positioning of initrd images:
3537 If this variable is not set, initrd images will be
3538 copied to the highest possible address in RAM; this
3539 is usually what you want since it allows for
3540 maximum initrd size. If for some reason you want to
3541 make sure that the initrd image is loaded below the
3542 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3543 variable to a value of "no" or "off" or "0".
3544 Alternatively, you can set it to a maximum upper
3545 address to use (U-Boot will still check that it
3546 does not overwrite the U-Boot stack and data).
3548 For instance, when you have a system with 16 MB
3549 RAM, and want to reserve 4 MB from use by Linux,
3550 you can do this by adding "mem=12M" to the value of
3551 the "bootargs" variable. However, now you must make
3552 sure that the initrd image is placed in the first
3553 12 MB as well - this can be done with
3555 setenv initrd_high 00c00000
3557 If you set initrd_high to 0xFFFFFFFF, this is an
3558 indication to U-Boot that all addresses are legal
3559 for the Linux kernel, including addresses in flash
3560 memory. In this case U-Boot will NOT COPY the
3561 ramdisk at all. This may be useful to reduce the
3562 boot time on your system, but requires that this
3563 feature is supported by your Linux kernel.
3565 ipaddr - IP address; needed for tftpboot command
3567 loadaddr - Default load address for commands like "bootp",
3568 "rarpboot", "tftpboot", "loadb" or "diskboot"
3570 loads_echo - see CONFIG_LOADS_ECHO
3572 serverip - TFTP server IP address; needed for tftpboot command
3574 bootretry - see CONFIG_BOOT_RETRY_TIME
3576 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3578 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3580 ethprime - controls which interface is used first.
3582 ethact - controls which interface is currently active.
3583 For example you can do the following
3585 => setenv ethact FEC
3586 => ping 192.168.0.1 # traffic sent on FEC
3587 => setenv ethact SCC
3588 => ping 10.0.0.1 # traffic sent on SCC
3590 ethrotate - When set to "no" U-Boot does not go through all
3591 available network interfaces.
3592 It just stays at the currently selected interface.
3594 netretry - When set to "no" each network operation will
3595 either succeed or fail without retrying.
3596 When set to "once" the network operation will
3597 fail when all the available network interfaces
3598 are tried once without success.
3599 Useful on scripts which control the retry operation
3602 npe_ucode - set load address for the NPE microcode
3604 tftpsrcport - If this is set, the value is used for TFTP's
3607 tftpdstport - If this is set, the value is used for TFTP's UDP
3608 destination port instead of the Well Know Port 69.
3610 tftpblocksize - Block size to use for TFTP transfers; if not set,
3611 we use the TFTP server's default block size
3613 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3614 seconds, minimum value is 1000 = 1 second). Defines
3615 when a packet is considered to be lost so it has to
3616 be retransmitted. The default is 5000 = 5 seconds.
3617 Lowering this value may make downloads succeed
3618 faster in networks with high packet loss rates or
3619 with unreliable TFTP servers.
3621 vlan - When set to a value < 4095 the traffic over
3622 Ethernet is encapsulated/received over 802.1q
3625 The following image location variables contain the location of images
3626 used in booting. The "Image" column gives the role of the image and is
3627 not an environment variable name. The other columns are environment
3628 variable names. "File Name" gives the name of the file on a TFTP
3629 server, "RAM Address" gives the location in RAM the image will be
3630 loaded to, and "Flash Location" gives the image's address in NOR
3631 flash or offset in NAND flash.
3633 *Note* - these variables don't have to be defined for all boards, some
3634 boards currenlty use other variables for these purposes, and some
3635 boards use these variables for other purposes.
3637 Image File Name RAM Address Flash Location
3638 ----- --------- ----------- --------------
3639 u-boot u-boot u-boot_addr_r u-boot_addr
3640 Linux kernel bootfile kernel_addr_r kernel_addr
3641 device tree blob fdtfile fdt_addr_r fdt_addr
3642 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3644 The following environment variables may be used and automatically
3645 updated by the network boot commands ("bootp" and "rarpboot"),
3646 depending the information provided by your boot server:
3648 bootfile - see above
3649 dnsip - IP address of your Domain Name Server
3650 dnsip2 - IP address of your secondary Domain Name Server
3651 gatewayip - IP address of the Gateway (Router) to use
3652 hostname - Target hostname
3654 netmask - Subnet Mask
3655 rootpath - Pathname of the root filesystem on the NFS server
3656 serverip - see above
3659 There are two special Environment Variables:
3661 serial# - contains hardware identification information such
3662 as type string and/or serial number
3663 ethaddr - Ethernet address
3665 These variables can be set only once (usually during manufacturing of
3666 the board). U-Boot refuses to delete or overwrite these variables
3667 once they have been set once.
3670 Further special Environment Variables:
3672 ver - Contains the U-Boot version string as printed
3673 with the "version" command. This variable is
3674 readonly (see CONFIG_VERSION_VARIABLE).
3677 Please note that changes to some configuration parameters may take
3678 only effect after the next boot (yes, that's just like Windoze :-).
3681 Command Line Parsing:
3682 =====================
3684 There are two different command line parsers available with U-Boot:
3685 the old "simple" one, and the much more powerful "hush" shell:
3687 Old, simple command line parser:
3688 --------------------------------
3690 - supports environment variables (through setenv / saveenv commands)
3691 - several commands on one line, separated by ';'
3692 - variable substitution using "... ${name} ..." syntax
3693 - special characters ('$', ';') can be escaped by prefixing with '\',
3695 setenv bootcmd bootm \${address}
3696 - You can also escape text by enclosing in single apostrophes, for example:
3697 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
3702 - similar to Bourne shell, with control structures like
3703 if...then...else...fi, for...do...done; while...do...done,
3704 until...do...done, ...
3705 - supports environment ("global") variables (through setenv / saveenv
3706 commands) and local shell variables (through standard shell syntax
3707 "name=value"); only environment variables can be used with "run"
3713 (1) If a command line (or an environment variable executed by a "run"
3714 command) contains several commands separated by semicolon, and
3715 one of these commands fails, then the remaining commands will be
3718 (2) If you execute several variables with one call to run (i. e.
3719 calling run with a list of variables as arguments), any failing
3720 command will cause "run" to terminate, i. e. the remaining
3721 variables are not executed.
3723 Note for Redundant Ethernet Interfaces:
3724 =======================================
3726 Some boards come with redundant Ethernet interfaces; U-Boot supports
3727 such configurations and is capable of automatic selection of a
3728 "working" interface when needed. MAC assignment works as follows:
3730 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
3731 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
3732 "eth1addr" (=>eth1), "eth2addr", ...
3734 If the network interface stores some valid MAC address (for instance
3735 in SROM), this is used as default address if there is NO correspon-
3736 ding setting in the environment; if the corresponding environment
3737 variable is set, this overrides the settings in the card; that means:
3739 o If the SROM has a valid MAC address, and there is no address in the
3740 environment, the SROM's address is used.
3742 o If there is no valid address in the SROM, and a definition in the
3743 environment exists, then the value from the environment variable is
3746 o If both the SROM and the environment contain a MAC address, and
3747 both addresses are the same, this MAC address is used.
3749 o If both the SROM and the environment contain a MAC address, and the
3750 addresses differ, the value from the environment is used and a
3753 o If neither SROM nor the environment contain a MAC address, an error
3756 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
3757 will be programmed into hardware as part of the initialization process. This
3758 may be skipped by setting the appropriate 'ethmacskip' environment variable.
3759 The naming convention is as follows:
3760 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
3765 U-Boot is capable of booting (and performing other auxiliary operations on)
3766 images in two formats:
3768 New uImage format (FIT)
3769 -----------------------
3771 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3772 to Flattened Device Tree). It allows the use of images with multiple
3773 components (several kernels, ramdisks, etc.), with contents protected by
3774 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3780 Old image format is based on binary files which can be basically anything,
3781 preceded by a special header; see the definitions in include/image.h for
3782 details; basically, the header defines the following image properties:
3784 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3785 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3786 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
3787 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
3789 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3790 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3791 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
3792 * Compression Type (uncompressed, gzip, bzip2)
3798 The header is marked by a special Magic Number, and both the header
3799 and the data portions of the image are secured against corruption by
3806 Although U-Boot should support any OS or standalone application
3807 easily, the main focus has always been on Linux during the design of
3810 U-Boot includes many features that so far have been part of some
3811 special "boot loader" code within the Linux kernel. Also, any
3812 "initrd" images to be used are no longer part of one big Linux image;
3813 instead, kernel and "initrd" are separate images. This implementation
3814 serves several purposes:
3816 - the same features can be used for other OS or standalone
3817 applications (for instance: using compressed images to reduce the
3818 Flash memory footprint)
3820 - it becomes much easier to port new Linux kernel versions because
3821 lots of low-level, hardware dependent stuff are done by U-Boot
3823 - the same Linux kernel image can now be used with different "initrd"
3824 images; of course this also means that different kernel images can
3825 be run with the same "initrd". This makes testing easier (you don't
3826 have to build a new "zImage.initrd" Linux image when you just
3827 change a file in your "initrd"). Also, a field-upgrade of the
3828 software is easier now.
3834 Porting Linux to U-Boot based systems:
3835 ---------------------------------------
3837 U-Boot cannot save you from doing all the necessary modifications to
3838 configure the Linux device drivers for use with your target hardware
3839 (no, we don't intend to provide a full virtual machine interface to
3842 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
3844 Just make sure your machine specific header file (for instance
3845 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3846 Information structure as we define in include/asm-<arch>/u-boot.h,
3847 and make sure that your definition of IMAP_ADDR uses the same value
3848 as your U-Boot configuration in CONFIG_SYS_IMMR.
3851 Configuring the Linux kernel:
3852 -----------------------------
3854 No specific requirements for U-Boot. Make sure you have some root
3855 device (initial ramdisk, NFS) for your target system.
3858 Building a Linux Image:
3859 -----------------------
3861 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3862 not used. If you use recent kernel source, a new build target
3863 "uImage" will exist which automatically builds an image usable by
3864 U-Boot. Most older kernels also have support for a "pImage" target,
3865 which was introduced for our predecessor project PPCBoot and uses a
3866 100% compatible format.
3875 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3876 encapsulate a compressed Linux kernel image with header information,
3877 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3879 * build a standard "vmlinux" kernel image (in ELF binary format):
3881 * convert the kernel into a raw binary image:
3883 ${CROSS_COMPILE}-objcopy -O binary \
3884 -R .note -R .comment \
3885 -S vmlinux linux.bin
3887 * compress the binary image:
3891 * package compressed binary image for U-Boot:
3893 mkimage -A ppc -O linux -T kernel -C gzip \
3894 -a 0 -e 0 -n "Linux Kernel Image" \
3895 -d linux.bin.gz uImage
3898 The "mkimage" tool can also be used to create ramdisk images for use
3899 with U-Boot, either separated from the Linux kernel image, or
3900 combined into one file. "mkimage" encapsulates the images with a 64
3901 byte header containing information about target architecture,
3902 operating system, image type, compression method, entry points, time
3903 stamp, CRC32 checksums, etc.
3905 "mkimage" can be called in two ways: to verify existing images and
3906 print the header information, or to build new images.
3908 In the first form (with "-l" option) mkimage lists the information
3909 contained in the header of an existing U-Boot image; this includes
3910 checksum verification:
3912 tools/mkimage -l image
3913 -l ==> list image header information
3915 The second form (with "-d" option) is used to build a U-Boot image
3916 from a "data file" which is used as image payload:
3918 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3919 -n name -d data_file image
3920 -A ==> set architecture to 'arch'
3921 -O ==> set operating system to 'os'
3922 -T ==> set image type to 'type'
3923 -C ==> set compression type 'comp'
3924 -a ==> set load address to 'addr' (hex)
3925 -e ==> set entry point to 'ep' (hex)
3926 -n ==> set image name to 'name'
3927 -d ==> use image data from 'datafile'
3929 Right now, all Linux kernels for PowerPC systems use the same load
3930 address (0x00000000), but the entry point address depends on the
3933 - 2.2.x kernels have the entry point at 0x0000000C,
3934 - 2.3.x and later kernels have the entry point at 0x00000000.
3936 So a typical call to build a U-Boot image would read:
3938 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3939 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3940 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
3941 > examples/uImage.TQM850L
3942 Image Name: 2.4.4 kernel for TQM850L
3943 Created: Wed Jul 19 02:34:59 2000
3944 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3945 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3946 Load Address: 0x00000000
3947 Entry Point: 0x00000000
3949 To verify the contents of the image (or check for corruption):
3951 -> tools/mkimage -l examples/uImage.TQM850L
3952 Image Name: 2.4.4 kernel for TQM850L
3953 Created: Wed Jul 19 02:34:59 2000
3954 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3955 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3956 Load Address: 0x00000000
3957 Entry Point: 0x00000000
3959 NOTE: for embedded systems where boot time is critical you can trade
3960 speed for memory and install an UNCOMPRESSED image instead: this
3961 needs more space in Flash, but boots much faster since it does not
3962 need to be uncompressed:
3964 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
3965 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3966 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3967 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
3968 > examples/uImage.TQM850L-uncompressed
3969 Image Name: 2.4.4 kernel for TQM850L
3970 Created: Wed Jul 19 02:34:59 2000
3971 Image Type: PowerPC Linux Kernel Image (uncompressed)
3972 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3973 Load Address: 0x00000000
3974 Entry Point: 0x00000000
3977 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3978 when your kernel is intended to use an initial ramdisk:
3980 -> tools/mkimage -n 'Simple Ramdisk Image' \
3981 > -A ppc -O linux -T ramdisk -C gzip \
3982 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3983 Image Name: Simple Ramdisk Image
3984 Created: Wed Jan 12 14:01:50 2000
3985 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3986 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3987 Load Address: 0x00000000
3988 Entry Point: 0x00000000
3991 Installing a Linux Image:
3992 -------------------------
3994 To downloading a U-Boot image over the serial (console) interface,
3995 you must convert the image to S-Record format:
3997 objcopy -I binary -O srec examples/image examples/image.srec
3999 The 'objcopy' does not understand the information in the U-Boot
4000 image header, so the resulting S-Record file will be relative to
4001 address 0x00000000. To load it to a given address, you need to
4002 specify the target address as 'offset' parameter with the 'loads'
4005 Example: install the image to address 0x40100000 (which on the
4006 TQM8xxL is in the first Flash bank):
4008 => erase 40100000 401FFFFF
4014 ## Ready for S-Record download ...
4015 ~>examples/image.srec
4016 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4018 15989 15990 15991 15992
4019 [file transfer complete]
4021 ## Start Addr = 0x00000000
4024 You can check the success of the download using the 'iminfo' command;
4025 this includes a checksum verification so you can be sure no data
4026 corruption happened:
4030 ## Checking Image at 40100000 ...
4031 Image Name: 2.2.13 for initrd on TQM850L
4032 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4033 Data Size: 335725 Bytes = 327 kB = 0 MB
4034 Load Address: 00000000
4035 Entry Point: 0000000c
4036 Verifying Checksum ... OK
4042 The "bootm" command is used to boot an application that is stored in
4043 memory (RAM or Flash). In case of a Linux kernel image, the contents
4044 of the "bootargs" environment variable is passed to the kernel as
4045 parameters. You can check and modify this variable using the
4046 "printenv" and "setenv" commands:
4049 => printenv bootargs
4050 bootargs=root=/dev/ram
4052 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4054 => printenv bootargs
4055 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4058 ## Booting Linux kernel at 40020000 ...
4059 Image Name: 2.2.13 for NFS on TQM850L
4060 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4061 Data Size: 381681 Bytes = 372 kB = 0 MB
4062 Load Address: 00000000
4063 Entry Point: 0000000c
4064 Verifying Checksum ... OK
4065 Uncompressing Kernel Image ... OK
4066 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
4067 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4068 time_init: decrementer frequency = 187500000/60
4069 Calibrating delay loop... 49.77 BogoMIPS
4070 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4073 If you want to boot a Linux kernel with initial RAM disk, you pass
4074 the memory addresses of both the kernel and the initrd image (PPBCOOT
4075 format!) to the "bootm" command:
4077 => imi 40100000 40200000
4079 ## Checking Image at 40100000 ...
4080 Image Name: 2.2.13 for initrd on TQM850L
4081 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4082 Data Size: 335725 Bytes = 327 kB = 0 MB
4083 Load Address: 00000000
4084 Entry Point: 0000000c
4085 Verifying Checksum ... OK
4087 ## Checking Image at 40200000 ...
4088 Image Name: Simple Ramdisk Image
4089 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4090 Data Size: 566530 Bytes = 553 kB = 0 MB
4091 Load Address: 00000000
4092 Entry Point: 00000000
4093 Verifying Checksum ... OK
4095 => bootm 40100000 40200000
4096 ## Booting Linux kernel at 40100000 ...
4097 Image Name: 2.2.13 for initrd on TQM850L
4098 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4099 Data Size: 335725 Bytes = 327 kB = 0 MB
4100 Load Address: 00000000
4101 Entry Point: 0000000c
4102 Verifying Checksum ... OK
4103 Uncompressing Kernel Image ... OK
4104 ## Loading RAMDisk Image at 40200000 ...
4105 Image Name: Simple Ramdisk Image
4106 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4107 Data Size: 566530 Bytes = 553 kB = 0 MB
4108 Load Address: 00000000
4109 Entry Point: 00000000
4110 Verifying Checksum ... OK
4111 Loading Ramdisk ... OK
4112 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
4113 Boot arguments: root=/dev/ram
4114 time_init: decrementer frequency = 187500000/60
4115 Calibrating delay loop... 49.77 BogoMIPS
4117 RAMDISK: Compressed image found at block 0
4118 VFS: Mounted root (ext2 filesystem).
4122 Boot Linux and pass a flat device tree:
4125 First, U-Boot must be compiled with the appropriate defines. See the section
4126 titled "Linux Kernel Interface" above for a more in depth explanation. The
4127 following is an example of how to start a kernel and pass an updated
4133 oft=oftrees/mpc8540ads.dtb
4134 => tftp $oftaddr $oft
4135 Speed: 1000, full duplex
4137 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4138 Filename 'oftrees/mpc8540ads.dtb'.
4139 Load address: 0x300000
4142 Bytes transferred = 4106 (100a hex)
4143 => tftp $loadaddr $bootfile
4144 Speed: 1000, full duplex
4146 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4148 Load address: 0x200000
4149 Loading:############
4151 Bytes transferred = 1029407 (fb51f hex)
4156 => bootm $loadaddr - $oftaddr
4157 ## Booting image at 00200000 ...
4158 Image Name: Linux-2.6.17-dirty
4159 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4160 Data Size: 1029343 Bytes = 1005.2 kB
4161 Load Address: 00000000
4162 Entry Point: 00000000
4163 Verifying Checksum ... OK
4164 Uncompressing Kernel Image ... OK
4165 Booting using flat device tree at 0x300000
4166 Using MPC85xx ADS machine description
4167 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4171 More About U-Boot Image Types:
4172 ------------------------------
4174 U-Boot supports the following image types:
4176 "Standalone Programs" are directly runnable in the environment
4177 provided by U-Boot; it is expected that (if they behave
4178 well) you can continue to work in U-Boot after return from
4179 the Standalone Program.
4180 "OS Kernel Images" are usually images of some Embedded OS which
4181 will take over control completely. Usually these programs
4182 will install their own set of exception handlers, device
4183 drivers, set up the MMU, etc. - this means, that you cannot
4184 expect to re-enter U-Boot except by resetting the CPU.
4185 "RAMDisk Images" are more or less just data blocks, and their
4186 parameters (address, size) are passed to an OS kernel that is
4188 "Multi-File Images" contain several images, typically an OS
4189 (Linux) kernel image and one or more data images like
4190 RAMDisks. This construct is useful for instance when you want
4191 to boot over the network using BOOTP etc., where the boot
4192 server provides just a single image file, but you want to get
4193 for instance an OS kernel and a RAMDisk image.
4195 "Multi-File Images" start with a list of image sizes, each
4196 image size (in bytes) specified by an "uint32_t" in network
4197 byte order. This list is terminated by an "(uint32_t)0".
4198 Immediately after the terminating 0 follow the images, one by
4199 one, all aligned on "uint32_t" boundaries (size rounded up to
4200 a multiple of 4 bytes).
4202 "Firmware Images" are binary images containing firmware (like
4203 U-Boot or FPGA images) which usually will be programmed to
4206 "Script files" are command sequences that will be executed by
4207 U-Boot's command interpreter; this feature is especially
4208 useful when you configure U-Boot to use a real shell (hush)
4209 as command interpreter.
4215 One of the features of U-Boot is that you can dynamically load and
4216 run "standalone" applications, which can use some resources of
4217 U-Boot like console I/O functions or interrupt services.
4219 Two simple examples are included with the sources:
4224 'examples/hello_world.c' contains a small "Hello World" Demo
4225 application; it is automatically compiled when you build U-Boot.
4226 It's configured to run at address 0x00040004, so you can play with it
4230 ## Ready for S-Record download ...
4231 ~>examples/hello_world.srec
4232 1 2 3 4 5 6 7 8 9 10 11 ...
4233 [file transfer complete]
4235 ## Start Addr = 0x00040004
4237 => go 40004 Hello World! This is a test.
4238 ## Starting application at 0x00040004 ...
4249 Hit any key to exit ...
4251 ## Application terminated, rc = 0x0
4253 Another example, which demonstrates how to register a CPM interrupt
4254 handler with the U-Boot code, can be found in 'examples/timer.c'.
4255 Here, a CPM timer is set up to generate an interrupt every second.
4256 The interrupt service routine is trivial, just printing a '.'
4257 character, but this is just a demo program. The application can be
4258 controlled by the following keys:
4260 ? - print current values og the CPM Timer registers
4261 b - enable interrupts and start timer
4262 e - stop timer and disable interrupts
4263 q - quit application
4266 ## Ready for S-Record download ...
4267 ~>examples/timer.srec
4268 1 2 3 4 5 6 7 8 9 10 11 ...
4269 [file transfer complete]
4271 ## Start Addr = 0x00040004
4274 ## Starting application at 0x00040004 ...
4277 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4280 [q, b, e, ?] Set interval 1000000 us
4283 [q, b, e, ?] ........
4284 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4287 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4290 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4293 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4295 [q, b, e, ?] ...Stopping timer
4297 [q, b, e, ?] ## Application terminated, rc = 0x0
4303 Over time, many people have reported problems when trying to use the
4304 "minicom" terminal emulation program for serial download. I (wd)
4305 consider minicom to be broken, and recommend not to use it. Under
4306 Unix, I recommend to use C-Kermit for general purpose use (and
4307 especially for kermit binary protocol download ("loadb" command), and
4308 use "cu" for S-Record download ("loads" command).
4310 Nevertheless, if you absolutely want to use it try adding this
4311 configuration to your "File transfer protocols" section:
4313 Name Program Name U/D FullScr IO-Red. Multi
4314 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4315 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4321 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4322 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4324 Building requires a cross environment; it is known to work on
4325 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4326 need gmake since the Makefiles are not compatible with BSD make).
4327 Note that the cross-powerpc package does not install include files;
4328 attempting to build U-Boot will fail because <machine/ansi.h> is
4329 missing. This file has to be installed and patched manually:
4331 # cd /usr/pkg/cross/powerpc-netbsd/include
4333 # ln -s powerpc machine
4334 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4335 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4337 Native builds *don't* work due to incompatibilities between native
4338 and U-Boot include files.
4340 Booting assumes that (the first part of) the image booted is a
4341 stage-2 loader which in turn loads and then invokes the kernel
4342 proper. Loader sources will eventually appear in the NetBSD source
4343 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4344 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4347 Implementation Internals:
4348 =========================
4350 The following is not intended to be a complete description of every
4351 implementation detail. However, it should help to understand the
4352 inner workings of U-Boot and make it easier to port it to custom
4356 Initial Stack, Global Data:
4357 ---------------------------
4359 The implementation of U-Boot is complicated by the fact that U-Boot
4360 starts running out of ROM (flash memory), usually without access to
4361 system RAM (because the memory controller is not initialized yet).
4362 This means that we don't have writable Data or BSS segments, and BSS
4363 is not initialized as zero. To be able to get a C environment working
4364 at all, we have to allocate at least a minimal stack. Implementation
4365 options for this are defined and restricted by the CPU used: Some CPU
4366 models provide on-chip memory (like the IMMR area on MPC8xx and
4367 MPC826x processors), on others (parts of) the data cache can be
4368 locked as (mis-) used as memory, etc.
4370 Chris Hallinan posted a good summary of these issues to the
4371 U-Boot mailing list:
4373 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4374 From: "Chris Hallinan" <clh@net1plus.com>
4375 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4378 Correct me if I'm wrong, folks, but the way I understand it
4379 is this: Using DCACHE as initial RAM for Stack, etc, does not
4380 require any physical RAM backing up the cache. The cleverness
4381 is that the cache is being used as a temporary supply of
4382 necessary storage before the SDRAM controller is setup. It's
4383 beyond the scope of this list to explain the details, but you
4384 can see how this works by studying the cache architecture and
4385 operation in the architecture and processor-specific manuals.
4387 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4388 is another option for the system designer to use as an
4389 initial stack/RAM area prior to SDRAM being available. Either
4390 option should work for you. Using CS 4 should be fine if your
4391 board designers haven't used it for something that would
4392 cause you grief during the initial boot! It is frequently not
4395 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4396 with your processor/board/system design. The default value
4397 you will find in any recent u-boot distribution in
4398 walnut.h should work for you. I'd set it to a value larger
4399 than your SDRAM module. If you have a 64MB SDRAM module, set
4400 it above 400_0000. Just make sure your board has no resources
4401 that are supposed to respond to that address! That code in
4402 start.S has been around a while and should work as is when
4403 you get the config right.
4408 It is essential to remember this, since it has some impact on the C
4409 code for the initialization procedures:
4411 * Initialized global data (data segment) is read-only. Do not attempt
4414 * Do not use any uninitialized global data (or implicitely initialized
4415 as zero data - BSS segment) at all - this is undefined, initiali-
4416 zation is performed later (when relocating to RAM).
4418 * Stack space is very limited. Avoid big data buffers or things like
4421 Having only the stack as writable memory limits means we cannot use
4422 normal global data to share information beween the code. But it
4423 turned out that the implementation of U-Boot can be greatly
4424 simplified by making a global data structure (gd_t) available to all
4425 functions. We could pass a pointer to this data as argument to _all_
4426 functions, but this would bloat the code. Instead we use a feature of
4427 the GCC compiler (Global Register Variables) to share the data: we
4428 place a pointer (gd) to the global data into a register which we
4429 reserve for this purpose.
4431 When choosing a register for such a purpose we are restricted by the
4432 relevant (E)ABI specifications for the current architecture, and by
4433 GCC's implementation.
4435 For PowerPC, the following registers have specific use:
4437 R2: reserved for system use
4438 R3-R4: parameter passing and return values
4439 R5-R10: parameter passing
4440 R13: small data area pointer
4444 (U-Boot also uses R12 as internal GOT pointer. r12
4445 is a volatile register so r12 needs to be reset when
4446 going back and forth between asm and C)
4448 ==> U-Boot will use R2 to hold a pointer to the global data
4450 Note: on PPC, we could use a static initializer (since the
4451 address of the global data structure is known at compile time),
4452 but it turned out that reserving a register results in somewhat
4453 smaller code - although the code savings are not that big (on
4454 average for all boards 752 bytes for the whole U-Boot image,
4455 624 text + 127 data).
4457 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
4458 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
4460 ==> U-Boot will use P3 to hold a pointer to the global data
4462 On ARM, the following registers are used:
4464 R0: function argument word/integer result
4465 R1-R3: function argument word
4467 R10: stack limit (used only if stack checking if enabled)
4468 R11: argument (frame) pointer
4469 R12: temporary workspace
4472 R15: program counter
4474 ==> U-Boot will use R8 to hold a pointer to the global data
4476 On Nios II, the ABI is documented here:
4477 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4479 ==> U-Boot will use gp to hold a pointer to the global data
4481 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4482 to access small data sections, so gp is free.
4484 On NDS32, the following registers are used:
4486 R0-R1: argument/return
4488 R15: temporary register for assembler
4489 R16: trampoline register
4490 R28: frame pointer (FP)
4491 R29: global pointer (GP)
4492 R30: link register (LP)
4493 R31: stack pointer (SP)
4494 PC: program counter (PC)
4496 ==> U-Boot will use R10 to hold a pointer to the global data
4498 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4499 or current versions of GCC may "optimize" the code too much.
4504 U-Boot runs in system state and uses physical addresses, i.e. the
4505 MMU is not used either for address mapping nor for memory protection.
4507 The available memory is mapped to fixed addresses using the memory
4508 controller. In this process, a contiguous block is formed for each
4509 memory type (Flash, SDRAM, SRAM), even when it consists of several
4510 physical memory banks.
4512 U-Boot is installed in the first 128 kB of the first Flash bank (on
4513 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4514 booting and sizing and initializing DRAM, the code relocates itself
4515 to the upper end of DRAM. Immediately below the U-Boot code some
4516 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4517 configuration setting]. Below that, a structure with global Board
4518 Info data is placed, followed by the stack (growing downward).
4520 Additionally, some exception handler code is copied to the low 8 kB
4521 of DRAM (0x00000000 ... 0x00001FFF).
4523 So a typical memory configuration with 16 MB of DRAM could look like
4526 0x0000 0000 Exception Vector code
4529 0x0000 2000 Free for Application Use
4535 0x00FB FF20 Monitor Stack (Growing downward)
4536 0x00FB FFAC Board Info Data and permanent copy of global data
4537 0x00FC 0000 Malloc Arena
4540 0x00FE 0000 RAM Copy of Monitor Code
4541 ... eventually: LCD or video framebuffer
4542 ... eventually: pRAM (Protected RAM - unchanged by reset)
4543 0x00FF FFFF [End of RAM]
4546 System Initialization:
4547 ----------------------
4549 In the reset configuration, U-Boot starts at the reset entry point
4550 (on most PowerPC systems at address 0x00000100). Because of the reset
4551 configuration for CS0# this is a mirror of the onboard Flash memory.
4552 To be able to re-map memory U-Boot then jumps to its link address.
4553 To be able to implement the initialization code in C, a (small!)
4554 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4555 which provide such a feature like MPC8xx or MPC8260), or in a locked
4556 part of the data cache. After that, U-Boot initializes the CPU core,
4557 the caches and the SIU.
4559 Next, all (potentially) available memory banks are mapped using a
4560 preliminary mapping. For example, we put them on 512 MB boundaries
4561 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4562 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4563 programmed for SDRAM access. Using the temporary configuration, a
4564 simple memory test is run that determines the size of the SDRAM
4567 When there is more than one SDRAM bank, and the banks are of
4568 different size, the largest is mapped first. For equal size, the first
4569 bank (CS2#) is mapped first. The first mapping is always for address
4570 0x00000000, with any additional banks following immediately to create
4571 contiguous memory starting from 0.
4573 Then, the monitor installs itself at the upper end of the SDRAM area
4574 and allocates memory for use by malloc() and for the global Board
4575 Info data; also, the exception vector code is copied to the low RAM
4576 pages, and the final stack is set up.
4578 Only after this relocation will you have a "normal" C environment;
4579 until that you are restricted in several ways, mostly because you are
4580 running from ROM, and because the code will have to be relocated to a
4584 U-Boot Porting Guide:
4585 ----------------------
4587 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
4591 int main(int argc, char *argv[])
4593 sighandler_t no_more_time;
4595 signal(SIGALRM, no_more_time);
4596 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
4598 if (available_money > available_manpower) {
4599 Pay consultant to port U-Boot;
4603 Download latest U-Boot source;
4605 Subscribe to u-boot mailing list;
4608 email("Hi, I am new to U-Boot, how do I get started?");
4611 Read the README file in the top level directory;
4612 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
4613 Read applicable doc/*.README;
4614 Read the source, Luke;
4615 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
4618 if (available_money > toLocalCurrency ($2500))
4621 Add a lot of aggravation and time;
4623 if (a similar board exists) { /* hopefully... */
4624 cp -a board/<similar> board/<myboard>
4625 cp include/configs/<similar>.h include/configs/<myboard>.h
4627 Create your own board support subdirectory;
4628 Create your own board include/configs/<myboard>.h file;
4630 Edit new board/<myboard> files
4631 Edit new include/configs/<myboard>.h
4636 Add / modify source code;
4640 email("Hi, I am having problems...");
4642 Send patch file to the U-Boot email list;
4643 if (reasonable critiques)
4644 Incorporate improvements from email list code review;
4646 Defend code as written;
4652 void no_more_time (int sig)
4661 All contributions to U-Boot should conform to the Linux kernel
4662 coding style; see the file "Documentation/CodingStyle" and the script
4663 "scripts/Lindent" in your Linux kernel source directory.
4665 Source files originating from a different project (for example the
4666 MTD subsystem) are generally exempt from these guidelines and are not
4667 reformated to ease subsequent migration to newer versions of those
4670 Please note that U-Boot is implemented in C (and to some small parts in
4671 Assembler); no C++ is used, so please do not use C++ style comments (//)
4674 Please also stick to the following formatting rules:
4675 - remove any trailing white space
4676 - use TAB characters for indentation and vertical alignment, not spaces
4677 - make sure NOT to use DOS '\r\n' line feeds
4678 - do not add more than 2 consecutive empty lines to source files
4679 - do not add trailing empty lines to source files
4681 Submissions which do not conform to the standards may be returned
4682 with a request to reformat the changes.
4688 Since the number of patches for U-Boot is growing, we need to
4689 establish some rules. Submissions which do not conform to these rules
4690 may be rejected, even when they contain important and valuable stuff.
4692 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
4694 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
4695 see http://lists.denx.de/mailman/listinfo/u-boot
4697 When you send a patch, please include the following information with
4700 * For bug fixes: a description of the bug and how your patch fixes
4701 this bug. Please try to include a way of demonstrating that the
4702 patch actually fixes something.
4704 * For new features: a description of the feature and your
4707 * A CHANGELOG entry as plaintext (separate from the patch)
4709 * For major contributions, your entry to the CREDITS file
4711 * When you add support for a new board, don't forget to add this
4712 board to the MAINTAINERS file, too.
4714 * If your patch adds new configuration options, don't forget to
4715 document these in the README file.
4717 * The patch itself. If you are using git (which is *strongly*
4718 recommended) you can easily generate the patch using the
4719 "git format-patch". If you then use "git send-email" to send it to
4720 the U-Boot mailing list, you will avoid most of the common problems
4721 with some other mail clients.
4723 If you cannot use git, use "diff -purN OLD NEW". If your version of
4724 diff does not support these options, then get the latest version of
4727 The current directory when running this command shall be the parent
4728 directory of the U-Boot source tree (i. e. please make sure that
4729 your patch includes sufficient directory information for the
4732 We prefer patches as plain text. MIME attachments are discouraged,
4733 and compressed attachments must not be used.
4735 * If one logical set of modifications affects or creates several
4736 files, all these changes shall be submitted in a SINGLE patch file.
4738 * Changesets that contain different, unrelated modifications shall be
4739 submitted as SEPARATE patches, one patch per changeset.
4744 * Before sending the patch, run the MAKEALL script on your patched
4745 source tree and make sure that no errors or warnings are reported
4746 for any of the boards.
4748 * Keep your modifications to the necessary minimum: A patch
4749 containing several unrelated changes or arbitrary reformats will be
4750 returned with a request to re-formatting / split it.
4752 * If you modify existing code, make sure that your new code does not
4753 add to the memory footprint of the code ;-) Small is beautiful!
4754 When adding new features, these should compile conditionally only
4755 (using #ifdef), and the resulting code with the new feature
4756 disabled must not need more memory than the old code without your
4759 * Remember that there is a size limit of 100 kB per message on the
4760 u-boot mailing list. Bigger patches will be moderated. If they are
4761 reasonable and not too big, they will be acknowledged. But patches
4762 bigger than the size limit should be avoided.